Note: Descriptions are shown in the official language in which they were submitted.
WO 2023/277935
PCT/US2021/049200
POLYMER FOAM ARTICLES AND METHODS OF MAKING POLYMER
FOAMS
BACKGROUND
1.0011 Foamed polymer articles are widely employed in the industry due to the
highly
desirable attribute of providing high strength associate with solid polymer
articles, while
also delivering a reduction of density and therefore in the amount of polymer
used to
form an article of a selected volume. Additionally, the industry enjoys the
benefits
provided by the reduction in the weight of a foamed article compared with its
solid
counterpart, while still obtaining the benefits of strength, toughness, impact
resistance,
etc. delivered by the polymer itself.
1.0021 The industry has thus developed several now-conventional methods to
entrain gas
into thermoplastic polymers to make such foam articles. To mold a foamed
thermoplastic
polymer article using a gas, commercial guidelines and industrial practice
employ a melt
mixing apparatus operable to maintain a pressure to limit expansion of a gas
in the
interior of the apparatus while melt mixing the gas or a source of a gas with
the
thermoplastic polymer, further at a temperature above a melt temperature of
the
thermoplastic polymer. Such processes and apparatuses are designed to minimize
formation of pneumatoceles, or pockets of gas, that would otherwise form by
expansion
of the gas in the molten thermoplastic polymer. Thus, while residing within
and disposed
within the melt mixing apparatus, a thermoplastic polymer may include a source
of a gas
or the gas itself dissolved or dispersed therein, while including no
pneumatoceles or
substantially no pneumatoceles. A mixture of molten thermoplastic polymer and
a gas
that is at or above the temperature at which it would form pneumatoceles at
atmospheric
pressure, while including no pneumatoceles or substantially no pneumatoceles
may be
referred to as a molten pneumatic mixture. The temperature at which the gas,
or
pneumatogen, would form pneumatoceles in the molten pneumatic mixture at
atmospheric pressure may be referred to as the critical temperature. Melt
mixing
apparatuses well known in the art are thus designed and adapted to make and
dispense
molten pneumatic mixtures. Further, such apparatuses arc suitable to make
molten
pneumatic mixtures by adding a nascent, latent, or potential gas that is
released at a
characteristic temperature or that forms by exothermic or endothermic chemical
reaction
at a characteristic temperature. The critical temperature of a nascent,
latent, or potential
1
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
Ras is the temperature at which the reaction occurs or a gas is released into
the
thermoplastic polymer. All such materials and processes are well understood
and melt
mixing apparatuses of varying design are widely available commercially for
this purpose.
Melt mixing apparatuses commonly employed are single screw or twin screws
extruders
modified to have a pressurized chamber at the distal end of the screw to
receive a set
amount, or "shot" of a molten pneumatic mixture that travels during mixing by
operation
of the screw to urge the molten pneumatic mixture toward the pressurized
chamber.
[003] Upon building up the set amount or shot in the pressurized chamber, the
molten
pneumatic mixture is dispensed from the melt mixing apparatus and is directed
by fluidly
connected tubes, pipes, etc. into the cavity of a mold that obtains a desired
shape.
Dispensing is generally carried out to maximize the amount of foaming
(pneumatocele
formation) that occurs in the mold cavity by release of the pressure while the
thermoplastic polymer is still molten. The expanded foam in the cavity is then
cooled to
result in a foamed article. Foamed parts molded using this methodology are
referred to in
the art as injection molded foam parts. The techniques are generally limited
in scope to
make parts having thicknesses of about 2 cm or less.
[004] Injection molding processes employing pneumatogen sources to induce a
foam
structure in molded parts can be understood from a recent peer-reviewed
journal article
by Bociaga et al., "The influence of foaming agent addition, talc filler
content, and
injection velocity on selected properties, surface state, and structure of
polypropylene
injection molded parts." Cellular Polymers 2020, 39(1) 3-30. In this
publication the
process conditions typically employed for molding of standard injection molded
ISO test
bars of 4.1 mm thickness were systematically changed to create 16 different
combinations of the process settings and formulation variables (concentration
of
pneumatogen source, filler content, injection velocity, injection time, hold
time, and hold
pressure). The authors teach that manipulating the process and formulation
produces
some changes in the foam structure in the resulting foam parts, but all the
variables
produced parts having a "skin layer", which is a term of art to describe a
highly
characteristic region near the surface of an injection molded foam article
that is free or
substantially free of pneumatoceles.
[005] Inspection of the surface of an injection molded foamed article, and of
the area
extending about 500 microns beneath the surface in any direction, reveals a
solid
thermoplastic region - that is, the regions is free of pneumatoceles or
substantially free of
2
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
pneumatoceles. Foam parts arising from injection moldin.g in accordance with
conventional injection molding processes include the skin layer feature.
Additionally, the
skin layer of most such parts is significantly thicker than 500 p.m and may be
1 mm,
2mm, 3 mm, or even thicker depending on the methods, apparatuses, and
materials
employed.
1006.1 In order to make large foamed parts (such as pallets or wheelbarrow
bodies, for
example), the conventional processes above are insufficient because the large
mold
cavities induce an excess pressure drop as the molten pneumatic mixture flows
and
expands during tilling of the mold, and the pneumatoceles may form but then
coalesce or
leak from the viscous polymer flow during filling. Thus, in some cases of
"structural
Foam" molding, multiple nozzles are used simultaneously to fill large or thick
mold
cavities quickly. In other cases significant backpressure may be applied
within the mold
cavity to prevent pnetunatocele formation during filling; release of pressure
after filling
the mold operates to allow pneumatocele formation substantially within the
mold cavity.
Both approaches are often used in a single process.
10071 However, the foregoing structural foam molding processes do not solve a
problem
that has effectively blocked the industry from developing very large parts. As
is well
understood, areas near the surface of a molten mass will cool more rapidly
than the
interior thereof, and a cooling gradient of temperature develops within the
mass. The
cooling rate at points deepest within the mass are the slowest. In terms of
large mold
cavities filled with a mass of molten polymer or pneumatic mixture, an
interior region of
the mass may cool so slowly that viscous flow of the thermoplastic allows
pneumatocele
coalescence, forming large polymer-free pockets and disrupting the intended
continuous
polymer matrix defining such foams. This effect may be exacerbated by
shrinkage of
polymer volume as it cools to a temperature below a melt transition thereof.
For large
foamed parts, this effect can even lead to complete collapse of the foam
structure in the
interior of the part.
10081 The combined strength and density reduction associated with foamed
articles is
not realized without a continuous polymer matrix throughout the part. Foamed
parts
having large polymer-free areas or voids compromise the structural integrity
of the part,
which makes such parts unfit for its intended use. These severe technical
issues have
limited the industrial application of polymer foams to many otherwise highly
useful and
beneficial applications. Accordingly, there is an ongoing need to provide
improved
3
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
methods for making foamed articles, particularly large or thick foamed
articles. There is
an ongoing need to obtain parts having a continuous foam structure throughout.
There is
a particular need to obtain parts having a thickness greater than 2 cm and
having a
continuous foam structure throughout. There is an ongoing need in the industry
to
address such needs using conventional apparatuses and materials.
SUMMARY OF THE INVENTION
10091 Described herein is a method of making a molten polymer foam. The method
includes: adding a thermoplastic polymer and a pneumatogen source to an
extruder;
heating and mixing the thermoplastic polymer and pneumatogen source in the
extruder
under a pressure to form a molten pneumatic mixture, wherein the temperature
of the
molten pneumatic mixture exceeds the critical temperature of the pneumatogen
source;
collecting an amount of the molten pneumatic mixture in a collection area of
the extruder;
defining an expansion volume in the collection area to cause a pressure to
drop
(depressurization) in the collection area; allowing an expansion period of
time to elapse
after the defining; and dispensing a molten polymer foam from the collection
area. In
embodiments, the expansion volume is selected to provide between 10% and 300%
of the
total expected molten foam volume in the collection area, further wherein the
rate of
depressurization (that is, the rate of defining the pressure drop) is at least
0.01 GPa/s, in
embodiments 0.1 GPa/s or greater; and in some embodiments is 1.0 GPais or even
greater, such as up to 5.0 GPa/s. Depressurization rates of greater than 0.01
GPa/s are
referred to herein as "rapid depressurization". In some such embodiments,
rapid
depressurization is coupled with a high backpressure, wherein backpressure is
the amount
of pressure required e.g. in the collection area or in one or more additional
areas of the
apparatus used to carry out the depressurization, such as in a barrel area of
an injection
molding machine to initiate the depressurization, further wherein "high
backpressure"
means a backpressure of 500 kPa or greater, such as a backpressure of 500 kPa
and as
high as 25 MPa, further as limited by the injection molding machine employed
to carry
out the depressurization.
100101 By using the methods described herein, further employing rapid
depressurization
of the molten pneumatic mixture in the collection area, in embodiments further
employing high backpressure to initiate the rapid depressurization, a
stabilized molten
polymer foam is obtained that is capable of forming polymer foam articles
having a shape
4
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
and volume sufficient to accommodate a theoretical 20 cm ¨ 1000 cm. diameter
sphere in
at least one location in the interior thereof, and are further characterized
as having a
continuous thermoplastic polymer matrix defining a plurality of pneurnatoceles
throughout the entirety of the article, and total article volumes of 1000 cm3
and greater,
2000 cm3or greater, 3000 cm3or greater, 4000 cm3or greater, or 5000 cm3or
greater, or
2000 cm' to 5000 cm' or even greater. In some such embodiments, a surface
region
extending 500 microns from the surface of the article comprises compressed
pnetimatoceles throughout the entirety thereof.
100111 We have further found that by employing rapid depressurization of the
collection
area, in embodiments further employing high backpressure, an expansion period
between
0 seconds 5 seconds may be employed to obtain polymer foam articles
characterized as
having a continuous thermoplastic polymer matrix defining a plurality of
pneumatoceles
throughout the entirety of the article. We have further found that by
employing rapid
depressurization, in embodiments further employing high backpressure, an
expansion
period of between 600 seconds and 20(X) seconds or even longer can be
achieved. The
molten pneumatic mixture is undisturbed or substantially undisturbed during
the
expansion period.
100121 In some embodiments, the molten pneumatic mixture is subjected to 1 to
5 cycles
of pressurization followed by depressurization (obtaining a pressure drop),
prior to
dispensing the molten polymer foam from the collection area.
100131 In embodiments the dispensing is dispensing to a forming element; in
some
embodiments the forming element is a mold. In embodiments there is a fluid
connection
between the collection area of the extruder and the mold. In embodiments, the
dispensing
is an unimpeded flow of the molten polymer foam. In some embodiments, the
dispensing
is dispensing a linear flow of molten polymer foam. In embodiments, the molten
polymer foam contacts the mold and partially, substantially, or completely
fills the mold
cavity.
100141 In embodiments the method further comprises cooling the dispensed
molten
polymer foam to a temperature below a melt transition of the thermoplastic
polymer. In
embodiments, one or more additional materials to the extruder, wherein the one
or more
materials are selected from colorants, stabilizers, brighteners, nucleating
agents, fibers,
particulates, and fillers. In embodiments the pneurnatogen source is a
pneumatogen and
the addition is a pressurized addition. In other embodiments the pnetunatogen
source
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
comprises a bicarbonate, a polycarboxylic acid or a salt or ester thereof, or
a mixture
thereof.
100151 Also disclosed herein is a polymer foam article made in using the
methods,
materials, and apparatuses described herein. In embodiments, the polymer foam
article
has a foam structure throughout the entirety thereof characterized as a
continuous
polymer matrix defining a plurality of pncumatoccles therein. In embodiments,
a surface
region of a polymer foam article comprises compressed pneumatoceles. In
embodiments,
the surface region is the region extending 500 microns from the surface of the
article.
100161 Also disclosed herein are thermoplastic polymer foam articles, the
article having a
foam structure throughout the entirety thereof that is a continuous polymer
matrix
defining a plurality of pneumatoceles therein, further wherein a surface
region of the
article comprises compressed pneumatoceles. In some embodiments, the surface
region
is the region of the article extending 500 microns from the surface thereof.
In some
embodiments, the article comprises compressed pneumatoceles more than 500
microns
from the surface thereof
100171 In embodiments, the polymer foam article comprises a shape and a volume
wherein a sphere having a diameter of 2 cm or more would fit within the
polymer foam
article in at least one location, without protruding from the surface. In some
such
embodiments, the polymer foam article further includes one or more locations
wherein a
sphere having a diameter of 2 cm would not fit within the polymer foam
article, and
would protrude from the surface. In embodiments the polymer foam article has a
volume
of more than 1000 cm.3, 1000 cm3 to 5000 cm3, 2000 cm3 to 5000 cm3 or even
more than
5000 cm'. In embodiments, the polymer foam article has a shape and a volume
wherein
at least one (theoretical) sphere having a diameter between 2 cm and 1000 cm,
such as
between 20 cm and 1000 cm, would fit within the polymer foam article in at
least one
location, without protruding from the surface of the article. In embodiments,
the polymer
foam article comprises a volume of more than 2000 cm3 and a shape and a volume
wherein a sphere having a diameter of 2 cm or more would fit within the
polymer foam
article in at least one location, without protruding from the surface. In
embodiments, the
polymer foam article comprises a volume between 2000 cm3 and 5000 cm3 and a
shape
and volume wherein a sphere having a diameter of at least 20 cm would fit
within the
polymer foam article in at least one location, without protruding from the
surface. In
embodiments, the polymer foam article further comprises a volume of more than
5000
6
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
cm' and a shape wherein a sphere having a diameter of 20 cm to 1000 cm would
fit
within the polymer foam article in at least one location, without protruding
from the
surface. In embodiments, the polymer foam article comprises a shape wherein
one sphere
having a diameter of 20 cm to 1000 cm would fit within the polymer foam
article in at
least one location, without protruding from the surface; in other embodiments,
the
polymer foam article has a shape wherein two spheres having a diameter of 20
cm to
1000 cm would fit within the polymer foam article without protruding from the
surface.
In still other embodiments, the polymer foam article has a shape wherein three
or more
spheres having a diameter of 20 cm to 1000 cm would fit within the polymer
foam article
without protruding from the surface.
100181 In embodiments, materials used to make the polymer foam articles are
not
particularly limited and include thermoplastic polymers selected from
polyolefins,
polyamides, polyimides, polyesters, polycarbonates, poly (lactic acid)s ,
acrylonitrile-
butadiene-styrene copolymers, polystyrenes, polyurethanes, polyvinyl
chlorides,
copolymers of tetrafluoroethylene, polyethersulfones, polyacetals,
polyaramids,
polyphenylene oxides, polybutylenes, polybutadienes, polyacrylates and
methacryates,
ionomeric polymers, poly ether-amide block copolymers, polyaryletherkeytones,
polysulfones, polyphenylene sulfides, polyamide-imide copolymers,
poly(butylene
succinate)s, cellulosics, polysaccharides, and copolymers, alloys, admixtures,
and blends
thereof. In some embodiments, the thermoplastic polymer is a mixed plastic
waste
stream. The continuous polymer matrix optionally further includes one or more
additional materials selected from colorants, stabilizers, brighteners,
nucleating agents,
fibers, particulates, and fillers.
100191 We have found that the polymer foam articles formed using the foregoing
processes are 100% recyclable by subsequent melt molding processes. The
polymer
foam articles made in accordance with the methods described herein, may be
recycled
using the methods described herein. Thus, in embodiments, a first polymer foam
article
in accordance with any of the embodiments described herein, and formed in
accordance
with any of the methods described herein, is also a source of thermoplastic
polymer for
forming a second polymer foam article in accordance with the methods described
herein.
In such embodiments, the first polymer foam article is a recycled material
feedstock
when used to make a second polymer foam article.
7
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
100201 Other objects and features will be in part apparent and in part pointed
out
hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
100211 FIGS. 1A-1B illustrate a melt mixing apparatus useful for carrying out
the
methods described herein.
100221 FIG. 2-1 is a photographic image of a part molded according to the
standard foam
molding process as described in Example 1.
100231 FIG. 2-2 is a photographic image of a part molded according to a molten-
foam
injection molding (MFIM) process as described in Example 1.
100241 FIG. 2-3 is a photographic image of a piece cut from the part made
according to
the standard foam molding process as described in Example 1.
100251 FIG. 2-4 is a photographic image of a piece cut from the part made
according to
the MFIM process as described in Example I.
100261 FIG. 2-5 is a photographic image of a piece cut from the part made
according to
the standard foam molding process as described in Example I.
100271 FIG.. 2-6 is a photographic image of a piece cut from the part made
according to
the WW1 process as described in Example I.
100281 FIG. 3A is a photographic image of a cross section of Part A made
according to a
standard foam molding process and cut into two pieces to reveal a cross
section, as
described in Example 2.
100291 FIG. 3B is a photographic image of a cross section of Part B made
according to an
MFIM process and cut into two pieces to reveal a cross section, as described
in Example
2.
100301 FIG. 4A is a photographic image of a cross section of Part C made
according to
an MFIM process and cut into two pieces to reveal a cross section, as
described in
Example 2.
100311 FIG. 4B is a photographic image of a cross section of Part D made
according to a
standard foarn molding process and cut into two pieces to reveal a cross
section, as
described in Example 2.
100321 FIG.. 5 is a graph including plots of part density versus decompression
volume for
various decompression times for Trial B as described in Example 3.
100331 FIG. 6 is a graph including plots of strain versus time for parts made
in Trials A,
B, and C as described in Example 4.
8
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
100341 FIG. 7 shows photographic images of views in different aspects of Parts
A, B, and
C as described in Example 4.
[0035] FIG. 8 shows photographic images views of cross sections of Part A',
B', C', and
D' as described in Example 4.
100361 FIG. 9 is a drawing of two parts as described in Example 5.
100371 FIG. 10 is an isometric image of a tomography scan of the first part
made
according to an MFIM process as described in Example 6.
[0038] FIG. Ii is an image of the cross section plane shown in FIG. 10 as
described in
Example 6.
100391 FIG. 12 is a graph including plots of average cell size and cell count
against cell
circularity for the first part made as described in Example 6.
[0040] FIG. 13 is drawing of an X-ray tomographic image of a cross section of
a second
(spherical) part as described in Example 6.
100411 FIG. 14 is a graph including plots of average cell size and cell count
against cell
circularity for the second (spherical) part made as described in Example 6.
100421 FIG.. 15 is a micrograph of a fracture surface of a fractured three-
inch diameter
composite sphere made according to an MFIM process, as described in Example 7.
100431 FIG. 16 is an image a micrograph of a fracture surface of a fractured
three-inch
diameter composite sphere made according to an MFIM process, as described in
Example
7.
100441 FIG. 17 is an image a micrograph of a fracture surface of a fractured
three-inch
diameter composite sphere made according to an MFIM process, as described in
Example
7.
100451 FIG. 18 is an image a micrograph of a fracture surface of a fractured
three-inch
diameter composite sphere made according to an MFIM process, as described in
Example
7.
[0046] FIG. 19 shows micrograph images of cross sections from ISO bar parts
made
according to standard foam molding process runs 10, 11, 14, and 15, as
described in
Example 8.
[0047] FIG.. 20 shows micrograph images of cross sections from ISO bar parts
made
according to MFIM process runs 9, 10, 15, and 16, as described in Example 8.
9
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
100481 FIG. 21 shows a micrograph of a cross section of an ISO bar part made
according
to the MFIM process of Run 9 and stress-strain plots of replicate parts made
according to
the MFIM process of Run 9, as described in Example 8.
100491 FIG. 22 includes a micrograph of a cross section of an ISO bar part
made
according to the standard foam molding process of Run 10 and stress-strain
plots of
replicate parts made according to the standard foam molding process of Run 10,
as
described in Example 8.
100501 FIG. 23 includes two images from X-ray tomography of an ISO bar part
made
according to the standard foam molding process of Run 15, as described in
Example 8.
100511 FIG. 24 includes two images from X-ray tomography of an ISO bar part
made
according to the MFIM process of Run 9, as described in Example 8.
100521 FIG. 25 is an image from an. X-ray scan of a large tensile bar part
made according
to an MFIM process, as described in Example 9.
100531 FIG. 26 includes cross sections of eight large tensile bar parts made
according to
MFIM processes, as described in Example 9.
100541 FIG. 27 is an X-ray tomography image of a large tensile bar part made
according
to an MFIM process, as described in Example 9.
100551 FIG. 28 includes a series of X-ray tomographic images at different
depths within a
tensile bar part made according to an MFIM process and a series of images at
different
depths within a tensile bar part made according to a standard foam molding
process, as
described in Example 10.
100561 FIG. 29 is a graph including a plot of cell count versus depth for the
tensile bar
part made according to an MFIM process and a plot of cell count versus depth
for the
tensile bar part made according to a standard foam molding process, as
described in
Example 10.
100571 FIG. 30 is a graph including a plot of cell circularity versus depth
for the tensile
bar part made according to an MFIM process and a plot of cell circularity
versus depth
for the tensile bar part made according to a standard foam molding process, as
described
in Example 10.
100581 FIG. 31 is a graph including a plot of cell size versus depth for the
tensile bar part
made according to an MFIM process and a plot of cell size versus depth for the
tensile
bar part made according to a standard foam molding process, as described in
Example 10.
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
100591 FIG. 32 is a photograph of Sample 20 made according to a reverse MFIM
process,
as described in Example 12.
100601 FIG. 33 is a photograph of Sample 10 made according to an MFIM process,
as
described in Example 12.
100611 FIG. 34 is a photograph showing a cross section of Sample 20 made
according to
a reverse MFIM process, as described in Example 12.
100621 FIG. 35 is a photograph showing a cross section of Sample 10 made
according to
an MFIM process, as described in Example 12.
100631 FIG. 36 is a plot of cell count versus depth (distance from surface)
for Sample 10
(MFIM) and Sample 20 (Reverse MFIM) as described in Example 12.
100641 FIG. 37 is a plot of cell size versus depth (distance from surface) for
Sample 10
(MFIM) and Sample 20 (Reverse MFIM) as described in Example 12.
100651 FIG. 38 is a graph including a plot of averaged stress versus strain
for Sample 10
(MFIM) and a plot for Sample 20 (Reverse MFIM) from compression modulus
measurements, as described in Example 12.
100661 FIG.. 39 is a graph including a plot of averaged stress versus strain
for Sample 10
(MFIM) and a plot for Sample 20 (Reverse MFIM) from flexural modulus
measurements,
as described in Example 12.
100671 FIG. 40 is a graph of plots of stress versus strain from compression
modulus
measurements made of three metallocene polyethylene (mPE) materials of
different
densities and made according to MFIM processes, as described in Example 14.
100681 FIG. 41 illustrates a mold configuration useful for carrying out the
methods
described herein.
100691 FIG. 42 is a photograph showing a part. Part 111, made without a
decompression
step, as described in Example 15.
100701 FIG. 43 is a part, Part 87, made according to an MFIM process as
described in
Example 15.
100711 FIG. 44 is a plot of injection pressure against barrel volume for the
molding
processes of Part 111 and the molding process of Part 87 as described in
Example 15.
100721 FIG.. 45 is a photograph of a cross section of Part 16A as described in
Example
16.
100731 FIG. 46 is a photograph of a cross section of Part 16AR as described in
Example
16.
11
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
100741 FIG. 47 is a photograph of a cross section of Part 16B as described in
Example
16.
100751 FIG. 48 is a photograph of a cross section of Part I6BR as described in
Example
16.
100761 FIG. 49 is a photograph of a cross section of Part 16C as described in
Example
16.
100771 FIG. 50 is a photograph of a cross section of Part 16CR as described in
Example
16.
100781 FIG. 51 is a photograph of a cross section of Part 16D as described in
Example
16.
100791 FIG. 52 is a photograph of a cross section of Part 16DR as described in
Example
16.
100801 FIG. 53 is a photograph of a cross section of Part 16E as described in
Example 16.
100811 FIG. 54 is a photograph of a cross section of Part 16ER as described in
Example
16.
100821 FIG.. 55 is a photograph of Part 1 made using no decompression, as
described in
Example 17.
100831 FIG. 56 is a photograph of a cross section of Part 2 made with a
decompression
time of 0.5 seconds, as described in Example 17.
100841 FIG. 57 is a photograph of a cross section of Part 3 made with a
decompression
time of 7 seconds, as described in Example 17.
100851 FIG. 58 is a photograph of a cross section of Part 1 after sectioning,
as described
in Example 18.
100861 FIG. 59 is a photograph of a cross section of Part 2 after sectioning,
as described
in Example 18.
100871 FIG. 60 shows a photograph of three brick parts made, as described in
Example
19, with one decompression step, three decompression steps, and five
decompression
steps.
100881 FIG. 61 shows magnified images of three brick parts made, as described
in
Example 19, with one decompression step, three decompression steps, and five
decompression steps.
12
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
100891 FIG. 62 is a plot of compressive strength. versus compressive strain
measured for
three parts made as described in Example 19, using one decompression step,
three
decompression steps, and five decompression steps.
[0090] FIG. 63 is a graphical representation of the force at peak measured
during stress-
strain tests of three parts made as described in Example .19, using one
decompression
step, three decompression steps, and five decompression steps.
100911 FIG. 64 is a graphical representation of the energy at peak measured
during stress-
strain tests of three parts made as described in Example 19, using one
decompression
step, three decompression steps, and five decompression steps.
100921 FIG. 65 shows a photograph of a cross section of a spherical SURLY-
1'4(TM) part
after sectioning and a magnified image of the cross section close to the
spherical surface
of the part, as described in Example 20.
100931 FIG. 66 shows a photograph of a cross section of a spherical
polyethylene part
after sectioning and a magnified image of the cross section close to the
spherical surface
of the part, as described in Example 20.
100941 FIG. 67 is a photograph of the two parts made as described in Example
21.
[0095] FIG 68 is a photographic image of the fourth part, molded using a
decompression
time of 10 seconds after applying a depressurization rate of 0.0009 GPa/sec,
as described
in Example 17.
100961 FIG. 691s a photographic image of the fifth part, molded using a
depressurization
rate of 0.0629 GPa/sec, as described in Example 17.
100971 FIG. 70 is a photograph of a sectioned block, Block 45 of 60, made as
described
in Example 22.
100981 FIG. 71 is a photograph of a sectioned block, Block 27 of 60, made as
described
in Example 22.
[0099] FIG. 72 is a photograph of a sectioned block. Block 60 of 60, made as
described
in Example 22.
1001001 FIG. 73 is a photograph of a fort built with bricks
made as described in
Example 22.
[00101] FIG. 74 shows photographic images of cross sections
of parts made
from 0%, 25%, 50%, and 100% recycled plastic, and on the right magnified
images of the
cross sections for parts made from 0% and 100% recycled material, as described
in
Example 23.
13
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1001021 Corresponding reference characters indicate
corresponding parts
throughout the drawings.
DETAILED DESCRIPTION
1001031 Although the present disclosure provides references
to preferred
embodiments, persons skilled in the art will recognize that changes may be
made in form
and detail without departing from the spirit and scope of the invention.
Various
embodiments will be described in detail with reference to the drawings,
wherein like
reference numerals represent like parts and assemblies throughout the several
views.
Reference to various embodiments does not limit the scope of the claims
attached hereto.
Additionally, any examples set forth in this specification are not intended to
be limiting
and merely set forth some of the many possible embodiments for the appended
claims.
1001041 Unless otherwise defined, all technical and
scientific terms used herein
have the same meaning as commonly understood by one of ordinary skill in the
art. In
case of conflict, the present document, including definitions, will control.
Preferred
methods and materials are described below, although methods and materials
similar or
equivalent to those described herein can be used in practice or testing of the
present
invention. All publications, patent applications, patents and other references
mentioned
herein are incorporated by reference in their entirety. The materials,
methods, and
examples disclosed herein are illustrative only and not intended to be
limiting.
1001051 As used herein, "polymer matrix", including
"continuous polymer
matrix", "thermoplastic polymer matrix", "molten polymer matrix" and like
terms refer
to a continuous solid or molten thermoplastic polymer phase or an amount of a
solid or
molten thermoplastic polymer defining a continuous phase.
1001061 As used herein, "molten mixture" means a molten
thermoplastic
polymer or mixture of molten thermoplastic polymers, optionally including one
or more
additional materials mixed with the molten thermoplastic polymer or mixture
thereof.
1001071 As used herein, "molten pneumatic mixture" means a
mixture of a
thermoplastic polymer and a pneumatogen. source, wherein the polymer is at a
temperature above a melt temperature thereof and the temperature of the
mixture exceeds
the critical temperature of the pneumatogen source, further wherein the
mixture is
characterized as having no pneumatoceles or substantially no pneumatoceles.
The molten
pneumatic mixture is present under a pressure sufficient to prevent
pneumatocele
14
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
formation, or substantially prevent pneumatocele formation, or cause the
pneumatogen
source to be dissolved or dispersed within the thermoplastic polymer either as
a gas or a
supercritical liquid. "Substantially prevent pneumatocele formation",
"substantially no
pneumatoceles" and like terms with respect to a molten pneumatic mixture means
that
while pressure conditions may be used to prevent pneumatocele formation in a
molten
mixture, defects, wearing of parts, and the like in processing equipment may
cause
unintentional pressure loss that does not interfere overall with obtaining and
maintaining
a pressurized molten mixture.
1001081 As used herein, "fi)am", "polymer foam",
thermoplastic polymer
foam", "molten foam", "molten polymer foam" and similar terms refer generally
to a
continuous polymer matrix defining a plurality of pneumatoce.les as a
discontinuous
phase dispersed therein.
1001091 As used herein, the term "pneumatocele" means a
discrete void
defined by and surrounded by a continuous thermoplastic polymer matrix.
1001101 As used herein, the term "pneumatogen" means a
gaseous compound
capable of defining a pneumatocele within a molten thermoplastic polymer
matrix.
[001111 As used herein, the term "critical temperature"
means the temperature
at which a pneumatogen source produces a pneumatogen at atmospheric pressure.
1001121 As used herein, the term "pneumatogen source" refers
to a latent,
potential, or nascent pneumatogen, added to or present within a thermoplastic
polymer
matrix, such as dissolved in the matrix and/or present as a supercritical
fluid therein; or in
the form. of an organic compound that produces a pneumatogen by a chemical
reaction; or
a combination of these; or wherein the pneumatogen source is a pneumatogen,
becomes a
pneumatogen, or produces a pneumatogen at a critical temperature
characteristic of the
pneumatogen source.
1001131 As used herein, the term "rapid depressurization" means a pressure
drop that
occurs at a rate of greater than 0.01 GPa/s, such as 0.01 GPa/s to 5 GPa/s.
[001141 As used herein, the term "high backpressure" means a backpressure of
500
kPa or greater, such as a backpressure of 500 kPa to 25 MPa, further wherein.
backpressure is the threshold amount of pressure required e.g. in the
collection area or
throughout the barrel of an injection molding machine that initiates
depressurization.
1001151 The terms "comprise(s)," "include(s)," "having,"
"has," "can,"
"contain(s)," and variants thereof, as used herein, are intended to be open-
ended
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
transitional phrases, terms, or words that do not preclude the possibility of
additional acts
or structures. The singular forms "a," "and" and "the" include plural
references unless the
context clearly dictates otherwise. The present disclosure also contemplates
other
embodiments "comprising," "consisting of and "consisting essentially of," the
embodiments or elements presented herein, whether explicitly set forth or not.
100116j As used herein, the term "optional" or "optionally"
means that the
subsequently described event or circumstance may but need not occur, and that
the
description includes instances where the event or circumstance occurs and
instances in
which it does not.
1001171 As used herein, the term "about" modifying, for
example, the quantity
of an ingredient in a composition, concentration, volume, process temperature,
process
time, yield, flow rate, pressure, and like values, and ranges thereof,
employed in
describing the embodiments of the disclosure, refers to variation in the
numerical
quantity that can occur, for example, through typical measuring and handling
procedures
used for making compounds, compositions, concentrates or use formulations;
through
inadvertent error in these procedures; through differences in the manufacture,
source, or
purity of starting materials or ingredients used to carry out the methods, and
like
proximate considerations. The term "about" also encompasses amounts that
differ due to
aging of a formulation with a particular initial concentration or mixture, and
amounts that
differ due to mixing or processing a formulation with a particular initial
concentration or
mixture. Where modified by the term "about" the claims appended hereto include
equivalents to these quantities. Further, where "about" is employed to
describe a range
of values, for example "about 1 to 5" the recitation means "1 to 5" and "about
1 to about
5" and "1 to about 5" and "about Ito 5" unless specifically limited by
context.
1001181 As used herein, the term "substantially" means
"consisting essentially
of', as that term is construed in U.S. patent law, and includes "consisting
of' as that term
is construed in U.S. patent law. For example, a composition that is
"substantially free" of
a specified compound or material may be free of that compound or material, or
may have
a minor amount of that compound or material present., such as through
unintended
contamination, side reactions, or incomplete purification. A "minor amount"
may be a
trace, an unmeasurable amount, an amount that does not interfere with a value
or
property, or some other amount as provided in context. A composition that has
"substantially only" a provided list of components may consist of only those
components,
16
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
or have a trace amount of some other component present, or have one or more
additional
components that do not materially affect the properties of the composition.
Additionally,
"substantially" modifying, for example, the type or quantity of an ingredient
in a
composition, a property, a measurable quantity, a method, a value, or a range,
employed
in describing the embodiments of the disclosure, refers to a variation that
does not affect
the overall recited composition, property, quantity, method, value, or range
thereof in a
manner that negates an intended composition, property, quantity, method,
value, or range.
Where modified by the term "substantially" the claims appended hereto include
equivalents according to this definition.
1001191 As used herein, any recited ranges of values
contemplate all values
within the range and are to be construed as support for claims reciting any
sub-ranges
having endpoints which are real number values within the recited range. By way
of a
hypothetical illustrative example, a disclosure in this specification of a
range of from Ito
shall be considered to support claims to any of the following ranges: 1-5; 1-
4; 1-3; 1-2;
2-5; 2-4; 2-3; 3-5; 3-4; and 4-5.
1001201 In embodiments disclosed herein, a method of
extruding a molten
polymer foam comprises, consists essentially of, or consists of adding a
thermoplastic
polymer and a pneumatogen source to an inlet situated on a first end of an
extruder;
heating and mixing the thermoplastic polymer and the pneumatogen source in the
extruder to form a molten pneumatic mixture, wherein the temperature of the
molten
pneumatic mixture exceeds the critical temperature of the pneumatogen source;
collecting
an. amount of the molten pneumatic mixture in a barrel region of the extruder
located
proximal to a second end of the extruder; forming an expansion volume in the
barrel
region, wherein the forming causes a pressure to drop in the barrel region;
allowing a
period of time to elapse after the pressure drop; and dispensing a molten
polymer foam
from the extruder.
1001.211 In embodiments, the extruder is any machine
designed and adapted for
melting, mixing, and dispensing thermoplastic polymers and mixtures thereof,
optionally
with one or more additional materials such as fillers, nucleating agents,
diluents,
stabilizers, brighteners, and the like; and further wherein the extruder
includes a
collection area for a collecting a mass of mixed, molten material and further
is capable of
forming an expansion volume in the collection area that is coupled with a
pressure drop.
Extruders are well known in the industry and are broadly used for melting,
mixing, and
17
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
manipulating molten thermoplastic polymers. In embodiments, the extruder is
adapted
and designed for melting, mixing, and dispensing a mixture of a thermoplastic
polymer
and a pneumatogen source. Such extruders are adapted to obtain molten
pneumatic
mixtures under a pressure sufficient to prevent or substantially prevent
pneumatocele
formation in the molten pneumatic mixture.
100122j In embodiments, extruders useful to carry out the
present methods
include an interior volume, referred to in the art as the 'barrel" of the
extruder, designed
and adapted for receiving a solid thermoplastic polymer, further for carrying
out the
melting and mixing thereof In embodiments, the extruder defines an interior
volume
designed for receiving a solid thermoplastic polymer and a pneumatogen or a
pneumatogen source, further for carrying out the melting of at least the
polymer and for
mixing the pneumatogen or pneumatogen source with the molten polymer to obtain
a
molten pneumatic mixture. In embodiments the extruder further includes a
collection
area for a collecting a mass of a molten pneumatic mixture material. In
embodiments the
extruder further includes means of forming an. expansion volume in. the
collection area
that is coupled with a pressure drop.
1001231 in embodiments, the extruder is an injection
molding machine. in
embodiments, the extruder is a SODICK" molding machine sold by Plustech Inc.
of
Schaumburg, IL. In embodiments, the extruder includes either one or two
members
known in the art as "screws" disposed within the interior volume, known in the
art as a
"barrel". In embodiments, the screws have a right circular cylindrical shape
overall, and
further include one or more protruding thread members referred to as
"flights". in some
embodiments the extruder is a single screw extruder, defined as including one
screw
movably disposed within the barrel for rotation of the cylinder around the
axis thereof,
for lateral movement of the cylinder along the axis thereof, or a combined
movement
comprising both rotation and lateral movement. In other embodiments the
extruder is a
twin screw extruder, defined as including two screws movably disposed within
the barrel
in substantially parallel and proximal relationship with respect to each
other, further
where each screw is movably disposed within the barrel for rotation of the
cylinder
around the axis thereof, for lateral movement of the cylinder along the axis
thereof, or a
combined movement comprising both rotation and lateral movement. The screws of
a
twin screw extruder are further arranged so that the action of the screws when
turned in
18
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
counter-rotating fashion define a designed mixing and transportation pattern
of a molten
thermoplastic polymer disposed within the barrel.
1001241 In embodiments, the extruder is further adapted and
designed to
receive a solid thermoplastic polymer. In embodiments, the barrel of the
extruder is
further adapted and designed to receive a solid thermoplastic polymer by
including an
inlet situated near a first end of the extruder and adapted to add a solid
thermoplastic
polymer to the barrel. The solid thermoplastic polymer is added to the inlet
in any
suitable format, for example beads, pellets, powders, ribbons, or blocks,
which are all
familiar formats to those of skill. In embodiments, the extruder includes
second, third, or
even fourth or higher numbers of inlets designed and adapted for adding or
introducing
one or more additional materials comprising one or more solids, liquids, or
gases to the
interior volume of the extruder, further for mixing the one or more additional
materials
with the thermoplastic polymer. The interior volume of the extruder is adapted
for
receiving, containing, and melting a thermoplastic polymer and optionally one
or more
additional materials; and subjecting the thermoplastic polymer and the
optional one or
more additional materials to heat, shear and mixing to form a molten mixture,
while
contemporaneously transporting the molten mixture in a direction generally
proceeding
from the first end thereof to a second end thereof. In embodiments where the
extruder is
a single screw extruder or a twin screw extruder, the shear, mixing, and
transportation is
accomplished by rotating the screw or counter-rotating two screws.
1001251 In embodiments the extruder interior volume, or a
portion thereof, is
surrounded or partly surrounded by one or more heat sources. Heat sources
suitably
adapted for heating the interior volume of an extruder include; in various
embodiments,
heated water jackets, heated oil jackets, electrical resistance heaters, open
or jacketed
flames, or another heat source. The heat source is operable to raise a
temperature in the
interior volume of the extruder. The temperature is suitably selected by the
operator for
melting a thermoplastic polymer and/or maintaining a desired temperature
within a
portion of the interior volume of the extruder. In embodiments, an extruder is
adapted to
include more than one heat source, wherein the heat sources are independently
operable
to enable one of skill to provide a range of temperature "zones" within the
interior
volume. Additional temperature zones may be included in some extruders in
association
with adding one or more materials to an inlet thereof or dispensing one more
materials
from an. outlet thereof. In embodiments, temperatures within the one or more
19
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
temperature zones are set by the operator for increased control and
optimization of
melting, mixing, shearing, and transportation of the thermoplastic polymer and
optionally
one or more additional materials.
1001261 The extruder is conventionally designed and adapted
to apply and
maintain a pressure within the interior volume thereof during the heating,
mixing and
transportation of a molten mixture. In embodiments, the extruder is designed
and
adapted to apply and maintain a first pressure within the interior volume or
barrel during
the beating, mixing and transportation of a molten mixture. In embodiments,
the pressure
inside the barrel during the heating, mixing and transportation of a molten
pneumatic
mixture is sufficient to prevent or substantially prevent leakage of molten
pneumatic
mixture from the barrel. In embodiments, the pressure within the barrel is
sufficient to
prevent a molten pneumatic mixture from developing pneumatoceles when a
temperature
within the barrel exceeds the critical temperature of the pneurnatogen source.
In
embodiments, the pressure within the barrel is substantially sufficient to
prevent a molten
pneumatic mixture from. developing pneumatoceles when a temperature within the
barrel.
exceeds the critical temperature of the pneumatogen source. In such
embodiments
described in this paragraph, "substantially" refers to inadvertent leaking of
material or
inadvertent loss of pressure from the barrel due to manufacture, age, or
manner of use of
the extruder and/or the screw as is familiar to one of skill. Further in such
embodiments
"substantially" in the context of "sufficient to prevent a molten pneumatic
mixture from
developing pneumatoceles", means that a small percentage, such as up to 10% of
the
pneumatogen may inadvertently form pneumatoceles while the pressure is
maintained on
a molten pneumatic mixture; but that it is the goal of the operator to
maintain sufficient
pressure to prevent pneumatoceles from forming.
1001271 In embodiments, the barrel of the extruder includes
a collection area
for collecting an amount of a molten mixture in preparation for dispensing the
molten
mixture from the extruder. The mass of the molten mixture is selected by the
user. In
embodiments, the molten mixture is a molten pneumatic mixture. In such
embodiments,
the term of art used to describe the collecting of a mass of a molten
pneumatic mixture in
a collection area of the barrel of the extruder is referred to as "building a
shot". As will
be understood by one skilled in the art of injection molding, to build a shot,
a mass of a
molten pneumatic mixture is collected by transporting the molten pneumatic
mixture
from the first end toward the second end of the extruder ¨ that is, toward and
into the
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
collection area - by the rotation of the screw or screws (or another mixing
element) and
by further allowing the molten pneumatic mixture to accumulate in the
collection area
until the entirety of the desired mass of molten pneumatic mixture is
collected and is
disposed in the collection area of the barrel. The collection area is situated
between the
screw or screws and the second end of the extruder. In some embodiments the
collection
area is in pressurized communication with the remainder of the barrel, while
in other
embodiments the collection area is pressurably isolated relative to the
remainder of the
barrel, for example by providing an o-ring, check ring, or other sealing
mechanism
annularly disposed around the screw or screws to seal or prcssurably isolate
the collection
area from the extruder barrel.
1001281 In conventional injection molding to form
thermoplastic polymer
foams, a mass of molten pneumatic mixture, or "shot", is collected or "built"
in the
collection area by transporting the molten pneumatic mixture toward and into
the
collection area by the rotation of the screw or screws (or another mixing
element). A
shot is said to be built when the entire selected mass of molten pneumatic
mixture is
disposed within the collection area. One of skill will appreciate that the
foregoing
description of melt mixing apparatuses, such as the mechanical elements and
features of
an extruder or other melt mixing apparatus, and further the foregoing
description of
methods of making and collecting molten pneumatic mixtures in a shot, is in
accord with
conventional apparatuses and methods of using such apparatuses to make molten
pneumatic mixtures and to build shots thereof.
1001291 In accord with these known methods and apparatuses,
a shot of molten
pneumatic mixture is conventionally prevented or substantially prevented from
developing pneumatoceles while present in the barrel, including during the
mixing,
heating, transporting, and collecting and further while disposed within the
collection area.
Conventionally, when a desired shot is collected in the collection area, a
nozzle, gate,
door, or other movable barrier situated between the collection area and an
outlet situated
on the second end of the ex-truder (in some embodiments a shut-off nozzle, as
will be
recognized by one of skill in the art of injection molding) is opened,
providing fluid
connection from the barrel to the outlet to dispense the shot from the
extruder. In some
embodiments when the gate or door is opened, a mechanical plunger is applied
to urge
the molten pneumatic mixture from the barrel and through the outlet. hi
embodiments
the extruder screw or screws are suitably employed in a lateral plunging
movement in a
21
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
direction toward the second end of the extruder, which in turn urges the
molten
pneumatic mixture from the collection area of the barrel and through the
outlet.
1001301 We have found that after building a shot of a molten
pneumatic
mixture in the collection area of an extruder, it is advantageous to form,
provide, or
define an expansion volume in the collection area of the extruder, wherein the
defining is
accompanied by a pressure drop in the collection area; allowing a period of
time to pass
after the defining, referred to herein as the expansion period; and dispensing
the shot
from the extruder after the expansion period. The shot in such embodiments is
dispensed
in the form of a molten polymer foam. In embodiments, the expansion volume is
defined
proximal to the shot disposed within the collection area of the extruder. In
embodiments,
the shot is not mixed or subjected to applied shear or extension while the
expansion
volume is in the process of being defined. In embodiments, the shot is not
transported
during the expansion period. In embodiments, the shot is allowed to stand, or
reside,
undisturbed or substantially undisturbed in the collection area during the
expansion
period. In any of the foregoing embodiments, the shot may be heated during the
expansion period; however, in some embodiments, no heat is added to the shot
during the
expansion period.
1001311 After the expansion period has elapsed or passed, a
molten polymer
foam may be dispensed from the second end of the extruder. The molten polymer
foam
includes a plurality of pneumatoceles. Without being limited by theory, we
believe that
the pneumatoceles form when the molten pneumatic mixture is subjected to the
expanded
volume and accompanying pressure drop (second pressure). In accord with known
principles of physics, the formation of the pneumatoceles is likely caused by
the defining
of the expanded volume and concomitant pressure drop in the collection area of
the
barrel, together with the expansion period in which the pneumatoceles form by
action of
the pneum.atogen. In some embodiments, defining the expansion volume after
building
the shot results in superior properties attributable to the molten polymer
foam that is
dispensed. Stated differently, we have found that fomiing a molten pneumatic
mixture
under pressure, followed by lowering the pressure and concomitantly forming a
defined
volume prior to dispensing the mixture (such as into a mold cavity), results
in a molten
polymer foam that upon cooling provides solidified polymer foam articles
having
unexpected and highly beneficial physical properties.
22
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1001321 We have discovered that molten polymer foams
dispensed from the
extruder in accord with the foregoing methods obtain significant technical
benefits.
These benefits are observed in the solidified polymer foams that result from
cooling the
molten polymer foam to a temperature below a melt transition temperature of
the
thermoplastic polymer. The structure of articles made using the molten polymer
foam
dispensed from an extruder after the expansion period is different both
macroscopically
and microscopically from polymer foams made by conventional methods; and
exhibit
superior properties suitable for structural members, for example. The polymer
foam
articles made using the methods, apparatuses, and materials described herein
that are
characterized as having a continuous thermoplastic matrix throughout the
entirety
thereof, and a plurality of pneumatoceles distributed throughout the entirety
of the
polymer foam article. This characterization is true for articles having a
shape and a
volume wherein a sphere having a diameter of 2 cm would fit within the polymer
foam
article in at least one location, without protruding from the surface. 'fills
characterization
is true for articles having a shape and a volume wherein a sphere having a
diameter of 2
cm would fit within the polymer foam article in at least one location, without
protruding
from the surface; fuither wherein the article has a total volume greater than
1000 cm',
greater than 2000 cm' , between 2000 cm' and 5000 cm', or even more than 5000
cm'.
1001331 In embodiments, the defining of the expansion volume
in a single
screw extruder is suitably achieved by moving the screw laterally toward a
first end of
the extruder and away from the collection area of the extruder where the shot
is collected.
In embodiments, the defining of th.e expansion volume in a twin screw extruder
is
achieved by moving both screws laterally toward a first end of the extruder
and away
from the region of the extruder where the shot is collected. The lateral
moving is
optionally accompanied by rotation of the screw or screws. That is, the one or
two
screws may be rotated during the lateral moving or the rotation m.ay be
stopped during
the lateral moving. It will be appreciated that the defming of the expansion
volume by
lateral movement of the one or two screws is advantageously selected by the
operator of
an extruder to provide a selected expansion volume. That is, the distance of
the lateral
movement of the screw or screws is suitably selected by the operator to define
the
selected expansion volume.
1001341 Accordingly, in embodiments, the expansion volume is
targeted by the
operator to add sufficient volume to the collection area to accommodate the
total
23
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
expected molten polymer foam volume; or som.e percentage of thereof The total
theoretical molten polymer foam volume of a shot may be calculated based on
the
amount of thermoplastic polymer and pneumatogen source plus any additional
materials
added to build the shot, further assuming all of the pneumatogen source will
contribute to
formation of pneumatoceles in the molten polymer foam to be obtained. The
total
expected molten polymer foam volume is the theoretical molten polymer foam
volume,
minus the expected amount of pneumatogen source dissolved in the polymer at
the
selected pressure (and therefore not contributing to pneumatoceles). Those of
skill will
understand that industrially obtained pneumatogen sources arc supplied with
information
suitable to calculate the total expected molten polymer foam volume based on
the amount
of pneumatogen source added to make the shot, and other processing conditions.
Solubility of the pneumatogen in the polymer should be taken into account, as
well as the
applied pressure during processing. In embodiments, the expansion volume is
the
difference between the shot volume and the expected molten polymer foam
volume. In
embodiments, the expansion volume is targeted to provide between 10% and 300%
of the
total expected molten polymer foam volume in the collection area, for example
between
15% and 300%; or between 20% and 300%, or between 25% and 300%, or between 30%
and 300%, or between 35% and 300%, or between 40% and 300%, or between 45% and
300%, or between 50% and 300%, or between 55% and 300%, or between 60% and
300%, or between 65% and 300%, or between 70% and 300%, or between 75% and
300%, or between 80% and 300%, or between 85% and 300%, or between 90% and
300%, or between 100% and 300%, or between 100% and 200%, or between 200% and
300%, or 100% to 105% or 100% to 110% or 100% to 115% or 100% to 120% or 105%
to 110% or 110% to 115% or 115% to 120% or 120% to 125% or 120% to 150% or
150% to 200% or 200% to 250% or 250% to 300%, or between 10% and 95%, or
between 10% and 90%, or between 10% and 85%, or between 10% and 80%, or
between
10% and 75%, or between 10% and 70%, or between 10% and 65%, or between 10%
and
60%; or between 10% and 55%, or between 10% and 50%, or between 10% and 45%,
or
between 10% and 40%, or between 10% and 35%, or between 10% and 30%, or
between
10% and 25%, or between 10% and 20%, or between 10% and 15%, or between 15%
and
20%, or between 20% and 25%, or between 25% and 30%, or between 30% and 35%,
or
between 35% and 40%, or between 40% and 45%, or between 45% and 50%, or
between
50% and 55%, or between 55% and. 60%, or between 60% and 65%, or between 65%
and
24
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
70%, or between 70% and 75%, or between 75% and 80%, or between 80% and 85%,
or
between 85% and 90%, or between 90% and 95%, or between 95% and 100% of the
difference between the shot volume and the expected molten polymer foam
volume.
[00135] In other embodiments, the expansion volume is targeted
to provide
between 0.1% and 10% of the total expected molten polymer foam volume in the
collection area, for example between 0.2% and 10%, or between 0.5% and 10%, or
between 1.0% and 10%, or between 1.5% and 10%, or between 2% and 10%, or
between
2.5% and 10%, or between 3% and .10%, or between 3.5% and .100%, or between 4%
and
10%, or between 4.5% and 10%, or between 5% and 10%, or between 6% and 10%, or
between 7% and 100%, or between 8% and 10%, or between 9% and 10%, or between
1% and 9%, or between 1% and 8%, or between 1% and 7%, or between 1% and 6%,
or
between 1% and 5%, or between I% and 4.5%, or between 1% and 4%, or between 1%
and 3.5%, or between 1% and 3%, or between 1% and 2.5%, or between 1% and 2%,
or
between 1% and 1.5%, or between 1.5% and 2%, or between 2% and 2.5%, or
between
2.5% and 3%, or between 3% and 3.5%, or between 3.5% and 4%, or between 4% and
4.5%, or between 4.5% and 5%, or between 5% and 6%, or between 6% and 7%, or
between 7% and 8%, or between 8% and 9%, or between 9% and 10% of the
difference
between the shot volume and the expected molten polymer foam volume.
[00136] After the expansion volume is defined, in some
embodiments a period
of time is allowed to pass, or elapse, prior to dispensing the molten polymer
foam from
the extruder. In embodiments the period of time is referred to as the
expansion period.
In some embodiments, during the expansion period no mixing, transporting,
shearing, or
other physical manipulation or additional volume changes are carried out
within the
collection area during the expansion period. Instead, in such embodiments the
shot is
allowed to stand within collection area during the expansion period. At the
end of the
expansion period, a molten polymer foam is dispensed from the extruder outlet.
In
embodiments, the molten polymer foam is dispensed into a mold cavity, and the
molten
polymer foam is cooled to a temperature below a melt transition of the
thermoplastic
polymer to obtain a solidified polymer foam article.
[00137] In embodiments, the expansion period is selected by
the operator to be
about 5 seconds to 600 seconds, depending on the mass of the sample,
pneumatogen
source and amount, and any additional materials present in the shot. In
embodiments, the
expansion period is 5 seconds to 600 seconds, or 5 seconds to 500 seconds, or
5 seconds
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
to 400 seconds, or 5 seconds to 300 seconds, or 20 seconds to 600 seconds, or
20 seconds
to 500 seconds, or 20 seconds to 400 seconds, or 20 seconds to 300 seconds, or
10
seconds to 200 seconds, or 20 seconds to 200 seconds, or 30 seconds to 200
seconds, or
40 seconds to 200 seconds, or 50 seconds to 200 seconds, or 5 seconds to 190
seconds, or
seconds to 180 seconds, or 5 seconds to 170 seconds, or 5 seconds to 160
seconds, or 5
seconds to 150 seconds, or 5 seconds to 140 seconds, or 5 seconds to 130
seconds, or 5
seconds to 120 seconds, or 5 seconds to 110 seconds, or 5 seconds to 100
seconds, or 5
seconds to 90 seconds, or 5 seconds to 80 seconds, or 5 seconds to 70 seconds,
or 5
seconds to 60 seconds, or 5 seconds to 50 seconds, or 5 seconds to 40 seconds,
or 5
seconds to 30 seconds, or 5 seconds to 20 seconds, or 5 seconds to 10 seconds,
or 10
seconds to 15 seconds, or 15 seconds to 20 seconds, or 20 seconds to 25
seconds, or 25
seconds to 30 seconds, or 30 seconds to 35 seconds, or 35 seconds to 40
seconds, or 40
seconds to 45 seconds, or 45 seconds to 50 seconds, or 50 seconds to 55
seconds, or 55
seconds to 60 seconds, or 60 seconds to 70 seconds, or 70 seconds to 80
seconds, or 80
seconds to 90 seconds, or 90 seconds to 100 seconds, or 100 seconds to 110
seconds, or
110 seconds to 120 seconds, or 120 seconds to 130 seconds, or 130 seconds to
140
seconds, or 140 seconds to 150 seconds, or 150 seconds to 160 seconds, or 160
seconds
to 170 seconds, or 170 seconds to 180 seconds, or 180 seconds to 190 seconds,
or 190
seconds to 200 seconds, or 200 seconds to 250 seconds, 250 seconds to 300
seconds, or
300 seconds to 350 seconds, or 350 seconds to 400 seconds, or 400 seconds to
450
seconds, or 450 seconds to 500 seconds, or 500 seconds to 550 seconds, or 550
seconds
to 600 seconds.
1001381 Additionally, we have found that expansion periods
such as 600
seconds to 2000 seconds or even longer, may be suitably selected by the
opemtor
depending on the mass of the sample, pneumatogen source and amount, and any
additional materials present in the shot. That is, even a very long residence
time in the
collection area --- 30 minutes or even longer - does not result in any
deleterious effects to
the molten pneumatic mixture or to the solidified polymer foams that result
after
dispensing and cooling the polymer foam. This result is unexpected, since the
molten
polymer foam has been allowed an expansion volume, and thus pneumatoceles have
formed and are dispersed within the molten, flowable polymer. One of skill
would not
expect the molten polymer foam to remain molten and undisturbed under reduced
pressure for up to 30 minutes or even longer, without significant migration of
26
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
pneumatoceles from the molten material, and concomitant loss of the continuous
polymer
matrix defining a plurality of pneumatoceles dispersed throughout the entirety
of the
resulting polymer foam articles.
1001.391 In embodiments, by using the methods described herein, and employing
rapid
depressurization of the molten pneumatic mixture in the collection area, and
in
embodiments further employing high backpressure to initiate the rapid
depressurization, a
molten polymer foam is obtained that requires no expansion period (expansion
period of
0 seconds) or requires only an expansion period of 0.1 second to 5 seconds,
such as 0-1
second, 1-2 seconds, 2-3 seconds, 3-4 seconds, or 4-5 seconds to provide a
molten
polymer foam capable of forming the polymer foam articles described herein. In
an
injection molding machine, this means that depressurization may be immediately
followed by dispensing the molten polymer foam. Thus, when using rapid
depressurization, the expansion period is selected by the operator to be about
5 seconds to
0 seconds, depending on the mass of the sample, pneumatogen source and amount,
and
any additional materials present in the shot. In embodiments, the expansion
period is 5
seconds to 0.2 seconds, or 5 seconds to 0.3 seconds, or 5 seconds to 0.4
seconds, or 5
seconds to 0.5 seconds, or 5 seconds to 0.6 seconds, or 5 seconds to 0.7
seconds, or 5
seconds to 0.8 seconds, or 5 seconds to 0.9 seconds, or 5 seconds to 1
seconds, or 5
seconds to 2 seconds, or 5 seconds to 3 seconds, or 5 seconds to 4 seconds, or
0.1 seconds
to 4 seconds, or 0.1 seconds to 3 seconds, or 0.1 seconds to 2 seconds, or 0.1
seconds to 1
second, or 1 second to 2 seconds, or 2 seconds to 3 seconds, or 3 seconds to 4
seconds, or
4 seconds to 5 seconds. Example 17 demonstrates an exemplary but nonlimiting
expansion period of 0.5 seconds. This expansion period is sufficient to result
in a
polymer foam article having a continuous polymer matrix defining a plurality
of
pneumatoceles dispersed throughout the entirety of the article, as shown in
FIG. 56.
1001401 Collectively, the depressurization at the selected depressurization
rate to
provide a pressure drop, followed by maintaining the reduced pressure for a
selected
period, may be referred to as a "depressurization step". Unexpectedly, we have
found
that the rate of depressurization is inversely related to the expansion period
required to
obtain a molten polymer foam that in turn provides a polymer foam article when
applied
to a forming element as described in any of the embodiments herein.
Specifically, we
have found that by applying rapid depressurization, an expansion time of 0
seconds to 5
seconds may be suitably selected. That is, by depressurizing the molten
pneumatic
27
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
mixture in the collection area at a rate of 0.01 GPais to 5.0 (Pais or higher,
in some
embodiments no expansion period is required in order to form a molten polymer
foam
that is dispensed to a forming element to provide a polymer foam article
having a shape
and volume sufficient to accommodate a theoretical 20 cm ¨ 1000 em diameter
sphere in
at least one location in the interior thereof, without protruding from the
surface. In some
such embodiments, rapid depressurization is coupled with a high backpressure
required to
initiate the depressurization, such as a backpressure of greater than 500 kPa,
such as a
backpressure of 500 kPa to 25 MPa or even higher, to obtain a very large
volume
polymer foam article. The polymer foam articles having a shape and volume
sufficient to
accommodate a theoretical 20 cm 1000 cm diameter sphere in at least one
location in
the interior thereof are further characterized as having a continuous
thermoplastic
polymer matrix defining a plurality of pneumatoceles throughout the entirety
of the
article. In some such embodiments, a surface region extending 500 microns from
the
surface of the article comprises compressed pneumatoceles throughout the
entirety
thereof.
1001411 In some embodiments, a depressurization step is
followed by one or more
additional pressurization/depressurization steps, for example 1 to 5 cycles of
pressurization followed by depressurization. A pressurization step is carried
out by
reducing the volume in the collection area proximal to the molten pneumatic
mixture,
wherein the reduced volume results in a pressure increase (pressurization).
The pressure
increase is then maintained for a pressurization period of less than one
second prior to
carrying out a second depressurization step. Additionally, the rate of
pressurization in a
pressurization step is selected to be 0.0059 GPa/sor more . That is, in
embodiments, the
rate of the defining of a reduced volume in the collection area, causing a
pressure
increase in the collection area, is 0.0059 GPa/s or more.
1001421 Thus, in embodiments, one or more
pressurization/depressurization
cycles are suitably carried out prior to dispensing a molten polymer foam from
the
collection area. For example, collecting a shot in the collection area under a
pressure is a
first pressurization step, and the first pressurization step is followed by a
first
depressurization step to complete a first pressurization/depressurization
cycle. In some
embodiments, a molten polymer foam is dispensed from the collection area after
a first
pressurization cycle. In other embodiments, a second pressurization step is
carried out
followed by a second depressurization step, to complete a second
28
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
pressurization/depressurization cycle. Third, fourth., or fifth.
pressurization/depressurization cycles may be further carried out before
dispensing a
molten polymer foam from the collection area. In Example 19, a single
pressurization/depressurization cycle is compared to 3 and 5
pressurization/depressurization cycles and resulting polymer foam articles are
described.
100143j In each of the 1 to 5
pressurization/depressurization cycles, each
pressurization cycle includes an individually selected reduced volume (or
applied
pressure) in the collection area as well as pressurization rate and
pressurization time, in
accordance with the foregoing parameters for pressurization. Additionally, in
each of the
1 to 5 pressurization/depressurization cycles, each depressurization cycle
includes an
individually selected expanded volume (or reduced pressure), expansion
(depressurization) rate, and expansion period in accordance with the foregoing
parameters for depressurization. In this manner, a customized
pressurization/depressurization profile may be suitably determined by the
operator to
achieve optimal results for forming a polymer foam article as described below.
Thus, in
some embodiments, a molten pneumatic mixture is subjected to 1 to 5 cycles of
pressurization/depressurization, prior to dispensing the molten polymer foam
from the
collection area, further wherein each step in each cycle may be individually
customized
for pressure change, rate of pressure change, and period of maintaining the
pressure
change, in order to provide an optimized volume/time or pressure/time profile
within the
collection area.
1001441 Using any of the foregoing methods results in
formation of a molten
polymer foam that obtains several significant technical benefits, described in
sections
below, when the molten polymer foam is cooled to a temperature below a melt
temperature of the thermoplastic polymer to yield a solidified polymer foam.
The
polymer foam articles are generally characterized as monolithic articles
having a
continuous polymer matrix defining a plurality of pneumatoceles dispersed
throughout
the entirety of the article. In embodiments the polymer foam articles are
particularly
characterized as having a continuous polymer matrix defining a plurality of
pneumatoceles dispersed in a surface region of the article, wherein the
surface region is
defined as the area of the article between the article surface (the polymer
foam-air
interface) and a distance 500 microns interior from the surface.
29
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
14:101451 A representative embodiment of an apparatus usefully
employed to carry
out the foregoing methods is shown in FIG. IA. FIG. IA is a schematic diagram
of an
exemplary single screw injection molding apparatus 20 in accordance with
disclosed
embodiments herein, that is useful to perfonn the methods described herein to
make
molten polymer foams and polymer foam articles also disclosed herein. As shown
in
FIG. IA, injection molding system 20 includes barrel 21, attached to motor or
drive
section 24 and mold section 26. Barrel 21 includes first end 21a, second end 2
lb, and
defines hollow interior barrel portion 22. Barrel portion 22 further defines
nozzle 36
proximal to barrel second end 21b. Screw 30 is disposed within barrel portion
22 and
comprises screw tip portion 34. Screw 30 is operably coupled to the motor
section 24 for
rotation of screw 30 around the central axis thereof; or for lateral movement
indicated by
arrow Z. Lateral movement of screw 30 may be in a direction generally from
barrel first
end 21a toward barrel second end 2lb; or in a direction from barrel second end
2 lb
toward barrel first end 21a. Lateral movement of screw 30 in either direction
is
optionally further coupled with rotational movement. Screw 30 further includes
one or
more flights 31 which are mixing elements for mixing and transporting
materials present
within barrel portion 22 generally from barrel first end 21a toward barrel
second end 21b.
Screw 30 is disposed within barrel portion 22 in pressurably sealed
relationship therein,
to enable pressures in excess of atmospheric pressure to be maintained within
barrel
portion 22, by screw flights 31 within the barrel 21 and further by situation
of check
valve 32. Shutoff valve 37 is connected to barrel 21 near second end 20b, and
is operable
to control a fluid connection, a pressurized connection, or both between
nozzle 36 and
mold section 26. Check valve 32 disposed within barrel portion 22 and
surrounding
screw 30 is operable to prevent backpressure from urging materials residing in
barrel
portion 22 toward barrel first end 21a and thus provides a pressurably sealed;
fluidly
sealed, or pressurably fluidly sealed relationship between shutoff valve 37
and check
valve 32.
1001461 Further with regard to FIG. IA, mold section 26
includes two mold
sections 38 as shown. Mold sections 38 are removably joined together to define
cavity
39. In some embodiments, one or more of the mold sections 38 are movable to
allow for
ejection of a solidified polymer foam article therefrom. In some embodiments,
the mold
sections 38 are situated in touching relation to each other; in other
embodiments mold
sections 28 are spaced apart by a gap.
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1001471 In embodiments, the methods disclosed herein are
suitably carried out
using an apparatus such as system 20 shown in FIGS. 1A-1B. In FIG. IA, a
selected
mass of mixture 42A comprising a selected amount of thermoplastic polymer,
pneumatogen source, and optionally one or more additional materials is added
to barrel
section 22 through inlet 28, as indicated by arrow A. In some embodiments,
th.e
pneumatogen source is a pneurnatogen and inlet 28 or another inlet (not shown)
is a gas
inlet in pressurized connection with barrel section 22; and the pneumatogen is
added to
the gas inlet at a selected pressure, while non-gaseous materials are added to
inlet 28.
During addition of mixture 42A to barrel portion 22 through inlet 28, motor 24
is
operable to rotate screw 30. The rotation of screw 30 transports and mixes the
mixture
42A to the screw tip 34. A heat source (not shown) is suitably employed to add
heat to
mixture 42A within the barrel portion 22. Motor 24 rotates screw 30 to
transport mixture
42A present in barrel portion 22 in a direction generally proceeding from
first end 21a of
barrel 21 towards second end 21b, until reaching screw tip 34. Additionally,
the rotation
of screw 30 provides mixing of mixture 42A during the transportation. As
mixture 42A
is transported and mixed by rotation of screw 30, heating elements or heating
bands (not
shown) proximal to barrel portion 22 operate to heat mixture 42A. Multiple
heating
zones may be present proximal to barrel portion 22 to vary the temperature
inside barrel
portion 22 between first end 21a and second end 2 lb of barrel 21. During
transportation,
screw 30 rotating within barrel portion 22 is operable to mix mixture 42A; and
heat is
added to the mixture as it is transported, thereby raising the temperature of
the mixture
above a melting point of the thermoplastic polymer to transform mixture 42A
into molten
pneumatic mixture 42B at least by reaching second end 21b of barrel 21.
Additionally,
disposition of screw 30 within barrel portion 22, further wherein flights 31
are in contact
with barrel 21 during rotation of screw 30; combined with check valve 32,
shutoff valve
37 in a closed position, or both provides a pressurably sealed relationship
within barrel
portion 22 whereby the molten pneumatic mixture 42B is present in barrel
portion 22
under a pressure in excess of atmospheric pressure. The pressure within barrel
portion 22
is sufficient to prevent or substantially prevent pneumatocele formation, even
if the
pneumatogen source is above its critical temperature.
1001481 Further, rotation of screw 30 operates to transport
the pressurized molten
pneumatic mixture toward screw tip 34, transporting or building up a selected
mass of
pressurized molten pneumatic mixture 42B within a collection area 40 of barrel
portion
31
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
22. Collection area 40 is defined as the region within the volume of barrel
portion 22
extending between check valve 32 and shutoff valve 37 in FIG. IA, further as a
region of
barrel portion 22 situated along X distance of barrel 21. A selected mass or
"shot" of
pressurized molten pneumatic mixture 42B is collected, or built up, in
collection area 40
of barrel portion 22. Pressure within the collection area 40 is sufficient to
prevent or
substantially prevent pneumatoc;ele formation in the molten pneumatic mixture.
In
embodiments, the shot substantially fills collection area 40.
1001491 Building the shot of molten pneumatic mixture 42B is
achieved using
conventional methods familiar to those of skill. Conventional and known
'variations in
methods and materials employed to build a shot for injection molding are
encompassed
by the methods described herein. Once a shot is built, it may be subjected to
the methods
disclosed herein to obtain all the technical benefits disclosed herein with
respect to
forming polymer foams and polymer foam articles. For example, to form a shot,
methods
such the MUCELL,e; high-pressure process employed by Trexel Inc. of
Wilmington, MA
are suitably employed, wherein addition of pnemnatogen source as a gas
directly to an.
extruder with pressurized mixing to prevent or substantially prevent
pneumatocele
formation is followed by shot collection. Various patent art and trade
publications further
describe specialized melt mixing and conveying designs for obtaining molten
pneumatic
mixtures and forming a shot, such as specialized screw designs for mixing and
backflow
patterns and the like; any of these may be usefully employed in conjunction
with the
foregoing shot formation methods and apparatuses to form a shot as described
herein and
collect the shot under a pressure within a collection area of a melt mixing
apparatus.
1001501 Once a shot is formed and collected in a collection
area, an expansion
volume is defined therein, further wherein the expansion is accompanied by a
drop in a
pressure in the collection area and proximal to the shot. In embodiments, the
pressure
drop is accomplished at a rate of 0.01 GPais or more. Accordingly, FIG. IA
depicts a
molten pneumatic mixture apparatus 20 wherein screw 30 is positioned to
collect a shot
of in collection area 40. The shot includes the selected mass of molten
pneumatic
mixture 428 and is disposed under a pressure within collection area 40. At
this stage of
the process, further relative to FIG. IA, FIG. I B depicts apparatus 20
wherein screw 30 is
positioned to define an expansion volume 44 within collection area 40. In
somewhat
more detail, FIG. 1B shows screw 30 in a position resulting from lateral
movement of
screw 30 toward barrel first end 21a; that is, screw 30 is retracted in FIG.
1B relative to
32
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
FIG. IA. Retraction and the resulting partial displacement of screw 30 from
collection
area 40 defines an expansion volume 44 within collection area 40 and further
causes a
pressure to drop within collection area 40. In some embodiments, screw 30 is
retracted
from collection area 40 at a rate that causes a rapid depressurization within
collection
area 40, such as 0.01 GPa/sec or greater. In some embodiments, rotation of
screw 30 is
halted before the retracting. In some embodiments, rotation of screw 30 is
halted during
the retracting, or after the retracting is completed. The retraction distance
of screw 30,
that is, the distance of lateral movement of screw 30 toward barrel first end
21.a is
selected by the operator to provide a suitable expansion volume 44.
1001511 In some embodiments represented in FIG. 1B, expansion
volume 44 is
selected by the operator to provide collection area 40 having a total volume
that matches
the total expected molten polymer foam volume of the shot; in such
embodiments, the
total volume in collection area 40 after adding expansion volume 44 is the
total expected
molten polymer foam volume of the molten pneumatic mixture 42B of FIG. 1B. In
other
embodiments, expansion volume 44 is selected by the operator to provide
collection area
40 having a total volume that is a percentage of the total expected molten
polymer foam
volume of a molten pneumatic mixture or shot residing in collection area 40;
that is, the
total volume in collection area 40 after adding expansion volume 44 equals
about 50% to
120% of the total expected molten polymer foam volume. In some embodiments,
expansion volume is set to provide a total volume in the collection area to
accommodate
100% of the total expected molten polymer foam volume.
1001521 After retracting screw 30 to define expansion volume 44 as shown in
FIG. 1B,
a period of time, referred to as the "expansion period" is allowed to elapse
or pass while
the shot is held within collection area 40 as shown in FIG. 1B, specifically
wherein
collection area 40 includes expansion volume 44. The expansion period is
selected by an
operator to be between 0 seconds and 2000 seconds. In embodiments, during the
expansion period the shot is allowed to stand undisturbed or substantially
undisturbed
within collection area 40. In embodiments, "undisturbed" means that the shot
is not
subjected to any processes causing mixing, shearing, or transporting (flow) of
the shot
during the expansion period. In embodiments, "substantially undisturbed" means
that the
shot is not purposefully perturbed by mixing, shearing, or transporting
processes carried
out during the expansion period but e.g. heat differentials, leakage, and
other
33
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
manufacturing issues may lead to inadvertent stress or strain to the shot
residing in the
collection area during the expansion period.
1001531 We have found that by retracting the screw 30 at a rapid rate, a rapid
rate of
depressurization rate can be achieved, for example at least 0.01 GPa/s, such
as 0.1 GPa/s
to 5 GPa/s, or higher than 5 GPa/s depending on the apparatus employed and
variables
such as mass of molten polymer in the collection area 40, amount of
pneumatogen or
pneumatogen source mixed with or dissolved in the molten polymer, and the
like. In
embodiments, rapid depressurization is coupled with a high backpressure
required to
initiate the depressurization, such as a backpressure of greater than 500 kPa,
such as a
backpressure of 500 kPa to 25 NI-Pa or even higher. After rapid
depressurization, the
molten polymer foam is dispensed to a forming element, such as a mold, and
cooled; or it
is repressurized/depressurized for one or more additional cycles prior to
dispensing to a
forming element and cooled; and the resulting polymer foam articles are
further
characterized as having a continuous thermoplastic polymer matrix defining a
plurality of
pneumatoceles throughout the entirety of the article. In some such
embodiments, a
surface region extending 500 microns from the surface of the article comprises
compressed pneumatoceles throughout the entirety thereof.
1001541 When further employed in conjunction with the methods described herein
for
forming a molten polymer foam, rapid pressure drop (depressurization),
optionally
coupled with high backpressure in an injection molding machine, provides
several
unexpected advantages.
1001551 First, rapid depressurization, optionally coupled with high
backpressure in an.
injection molding machine, enables formation of very large volume polymer foam
articles of nearly unlimited size and volume to be formed. Thus, polymer foam
articles
having a shape and volume sufficient to accommodate a theoretical 20 cm ¨ 1000
cm
diameter sphere in at least one location in the interior thereof, without
protruding from
the surface: or even larger articles are suitably formed using rapid
depressurization and
optionally high backpressure. The volume and dimensions achievable using rapid
depressurization are limited only by the amount of molten polymer that can be
collected
and machine limitations in introducing the pressure drop. The polymer foam
articles
having a shape and volume sufficient to accommodate a theoretical 20 cm ¨ 1000
cm
diameter sphere in at least one location in the interior thereof are further
characterized as
having a continuous thermoplastic polymer matrix defining a plurality of
pneumatoceles
34
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
throughout the entirety of the article. In some such embodiments, a surface
region
extending 500 microns from the surface of the article comprises compressed
pneumatoceles throughout the entirety thereof.
1001.561 Second, rapid depressurization, optionally coupled with high
backpressure in
an injection molding machine, allows an expansion period of 0 seconds to 5
seconds to be
selected, while still enabling formation of polymer foam articles having a
shape and
volume sufficient to accommodate a theoretical sphere having a diameter of at
least 2 cm
and as much as 1000 cm or more, in at least one location in the interior
thereof, without
protruding from the surface. The selection of an expansion period of 0 seconds
to 5
seconds is based on the type of thermoplastic polymer type used, amount of
pneumatogen
or prieumatogen source, and other specific and individual considerations of
the operator
in forming a polymer foam article in accord with the methods disclosed herein.
Rapid
depressurization; particularly when used concomitant with high backpressure,
provides a
stabilized molten polymer foam that does not require an expansion period, or
requires
only a very short expansion period, to obtain a molded polymer foam article
further
characterized as having a continuous thermoplastic polymer matrix defining a
plurality of
pneumatoceles throughout the entirety of the article. In some such
embodiments, a
surface region extending 500 microns from the surface of the article comprises
compressed pneumatoceles throughout the entirety thereof.
I00157j Third, rapid depressurization, optionally coupled with high
backpressure in an
injection molding machine, allows an expansion period of 600 seconds to 2000
seconds
to be selected, while still enabling formation of polymer foam articles having
a shape and
volume sufficient to accommodate a theoretical sphere having a diameter of at
least 2 cm
and as much as 1000 cm or more, in at least one location in the interior
thereof, without
protruding from the surface. Rapid depressurization, particularly when used
concomitant
with high backpressure, provides a stabilized molten polymer foam that can
withstand 30
minutes or more of residence time inside an injection molding machine and
still be
dispensed to a forming element to obtain a molded polymer foam article further
characterized as having a continuous thermoplastic polymer matrix defining a
plurality of
pneumatoceles throughout the entirety of the article. In some such
embodiments, a
surface region extending 500 microns from the surface of the article comprises
compressed pneumatoceles throughout the entirety thereof.
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1001581 Thus, a stabilized molten polymer foam is formed by using the methods
described herein, specifically where rapid depressurization is employed. The
stability of
the molten polymer foam is increased further, when employing an injection
molding
apparatus or machine such as the apparatus shown. in FIGS. 1.A-IB, by coupling
rapid
depressurization with high backpressure to initiate the depressurization. The
stability of
the molten polymer foam is evidenced by the surprising results that very large
articles can
be formed in a forming element; that the expansion period may be shortened or
excluded;
and also that a very long expansion period does not cause the stabilized
molten polymer
foam to collapse during the subsequent dispensing, molding, and cooling.
[00159] After the expansion period has elapsed, nozzle shutoff valve 37 as
shown in
FIG. 1B is opened and a molten polymer foam is dispensed from barrel 22. In
embodiments as shown in FIGS. IA-1B, the molten polymer foam flows into cavity
39.
The dispensing may be pressurized dispensing by mechanical means such as
plunging
using lateral movement of the screw, or by applying a pressurized gas to the
collection
area, but applying pressure is not necessary to dispense the molten polymer
foam in. som.e
embodiments. In embodiments, pressure at nozzle 36 as shown in FIGS I A-IB
during
dispensing of the molten polymer foam is 1 psi (about 7 kPa) to 20 psi (about
138 kPa) in
excess of gravity, such as, without adding external sources of pressure such
as by
plunging the molten polymer foam using additional lateral movement of the
screw 30
toward barrel second end 2Ib in FIGS. 1A-1B. In embodiments, the dispensing is
accomplished by maintaining fluid connection between nozzle 36 and cavity 39.
In some
such embodiments the fluid connection is further a pressurized connection. In
embodiments, pressure at nozzle 36 as shown in FIGS 1A-IB during dispensing of
the
molten polymer foam, also referred to as injection pressure, is about 500 kPa
to 500 MPa;
such as I MPa to 400 MPa, or 2 MPa to 300 MPa, or 3 MPa to 200 MPa, or 500 kPa
to 1
.MPa, I .MPa to 10 MPa., 10 .MPa to 50 MPa., 50 .MPa to 100 MPa, 100 MPa to
200 .MPa,
or 200 MPa to 500 MPa, for example by laterally urging screw 30 toward barrel
second
end 21b in FIGS. I A-1B or by applying another source of pressure, such as an
applied
gas pressure.
[00160] Alternatively, after retracting screw 30 as shown in FIG. 1B, and
maintaining
the position of screw 30 for an expansion period, screw 30 is urged back
towards barrel
second end 211); that is, screw 30 is returned partially or completely to the
position shown
in FIG. IA. in a pressurization step, which reduces the volume in collection
area 40 and
36
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
pressurizes the molten pneumatic mixture. The reduced volume within collection
area 40
causes a pressure to increase within collection area 40. In some embodiments,
rotation of
screw 30 is halted before the pressurization. In some embodiments, rotation of
screw 30
is halted during the pressurization, or after the pressurization is completed.
The
pressurization distance of screw 30, that is, the distance of lateral movement
of screw 30
toward barrel second end 2 lb is selected by the operator to provide a
suitable volume and
pressure. After a selected pressurization period, the operator may select
dispensing of the
molten pneumatic mixture, or may select one or more additional
pressurization/depressurization cycles prior to the dispensing.
1001611 In embodiments such as the foregoing where 1 to 5 pressurization/
depressurization cycles are employed, the operator may select the rates of
pressurization
and depressurization in addition to volume/pressure and the time of
maintaining the
pressurization or depressurization. Additionally, the operator may suitably
select rapid
depressurization; high backpressure, or both for each one or more of the
depressurization
steps of th.e one or more cycles.
1001621 Once disposed within cavity 39 defined by mold portions 38 shown in
FIGS.
1A-1B, the molten polymer foam is cooled or allowed to cool until it reaches a
temperature below a melt transition of the thermoplastic polymer, such as the
temperature
present in ambient conditions of the surrounding environment. In some
embodiments
where an expansion volume is set to provide a total volume in the collection
area that is
less than 100% of the total expected molten polymer foam volume, pneumatoceles
may
continue to nucleate and/or develop (grow in size) after the molten polymer
foam is
dispensed and before the temperature cools sufficiently to reach a melt
transition
temperature of the thermoplastic polymer. Cooling of the molten polymer foam
is
accomplished using conventional methods for cooling of injection molded
articles and
includes immersing the mold in a liquid coolant having a set temperature, or
spraying the
mold with a liquid coolant, such as liquid water: impinging an air stream onto
the mold;
ambient air cooling; and the like without limitation.
1001631 In an alternate embodiment of the foregoing methods, apparatus 20
configured
as shown in FIG. 1B is employed to form a molten polymer foam. FIG. 1B shows
screw
30 in a position resulting from lateral movement of screw 30 toward barrel
first end 21a;
that is, screw 30 is retracted in FIG. 1B relative to FIG. 1A. Retraction and
the resulting
partial displacement of screw 30 from collection area 40 defines an expansion
volume 44
37
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
within collection area 40 and further causes a pressure to drop within
collection area 40.
Apparatus 20 configuration as shown in FIG. 1B is employed to mix, heat, and
transport
molten pneumatic mixture 42B toward second end 21b of barrel 21 in
substantially the
same way as described above. Additionally, disposition of screw 30 within
barrel portion
22, further wherein flights 31 are in contact with barrel 21 during rotation
of screw 30;
combined with check valve 32, shutoff valve 37 in a closed position, or both
provides a
pressurably sealed relationship within barrel portion 22 whereby the molten
pneumatic
mixture 42B is present in barrel portion 22 under a pressure in excess of
atmospheric
pressure. The pressure within barrel portion 22 is sufficient to prevent or
substantially
prevent pneumatocele formation, even if the pneumatogen source is above its
critical
temperature. However, in this alternative embodiment the molten pnetunatic
mixture is
transported through check valve 32 and into collection area 40 further
appended by the
expansion volume 44.
1001641 Further in the alternate embodiment above, apparatus 20 in the
configuration
shown in FIG. 1B is employed to mix, heat, and transport molten pneumatic
mixture 42B
toward second end 21b of barrel 21; and then screw 30 is urged toward first
end 21a of
barrel 21 to pressurize the molten pneumatic mixture residing in collection
area 40.
Pressurization is following by rapid depressurization, optionally employed
with a high
backpressure, to obtain a stabilized polymer foam as described above
1001651 It is an advantage of the presently disclosed methods that
conventional
materials and apparatuses for extrusion and injection molding are useful for
carrying out
the methods. No specialized equipment or material requirements arc needed to
carry out
the disclosed methods. Thus, any thermoplastic polymer or in ixture thereof
that is useful
for injection molding and/or for forming polymer foams, is usefully combined
with any
industrially useful pneutnatogen source using conventional technology such as
a standard
injection molding apparatus, optionally together with one or more additional
materials as
selected by the operator of the apparatus.
1001661 In embodiments, thermoplastic polymers useful in conjunction with the
methods, apparatuses, and articles described herein include any thermoplastics
or
mixtures thereof that are known in the industry to be useful for injection
molding, or
injection molding of polymer foam articles; and mixtures of such polymers.
Useful
polymers are characterized as having a melt flow viscosity suitable for use in
injection
molding, such as in shot formation. As such, the thermoplastic polymers may
include a
38
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
degree of crossliakine that is themioreversible or that does not otherwise
prevent a
sufficient viscous melt flow for injection molding processes.
1001671 In embodiments, thermoplastic polymers useful in conjunction with the
methods, apparatuses, and articles described herein include olefiaic polymers
such as
polyethylene, polypropylene, poly a-olefins and various copolymers and
branchedicrosslinkcd variations thereof including but not limited to low
density
polyethylene (LDPE), high density polyethylene (HDPE), linear low density
polyethylene (LLDPE), thermoplastic polyolefin elastomer (TPE), ultra-high
molecular
weight polyethylene (UHMWPE), and the like; polyamidcs (PA), polyimides (P1),
polyesters such as polyester terepthalate (PET) and polybutyene terepthalate
(PBT),
polyhydroxyalkanoates (PHA) such as polyhydroxybutyrate (PHB), polycarbonates
(PC),
poly (lactic acid)s (PLA), acrylonitrile-butadiene-styrene copolymers (ABS),
polystyrenes, polyurethanes including thermoplastic polyurethane elastomers
(PU. TPU),
polycaprolactones, polyvinyl chlorides (PVC), copolymers of
tetrafluoroetliylene,
polyetbersulfones (PES), polyacetals, polyaramids, polyphenylen.e oxides
(PPO),
polybutylenes, polybutadienes, polyacrylates and methacryates (acrylics),
ionomeric
polymers (SURLYNe and similar ionically functionalized olefin copolymers),
poly
ether-amide block copolymers (PEBA.Xst), polyaryletherkeytones (PAEK),
polysulfones,
polyphenylene sulfides (PPS), polyamide-imide copolymers, poly(butylene
succinate)s,
cellulosics, polysaccharides, and copolymers, alloys, admixtures, and blends
thereof are
usefully employed in conjunction with the methods described herein, without
limitation.
1001681 Regarding unlimited use of polymer blends and mixtures, we have found
mixed stream recycled plastics are useful in embodiments as the thermoplastic
polymer.
Thus in embodiments ocean waste plastics are mixed streams of polymeric waste
harvested from oceans and beaches, and having exemplary content of 10%- 90%
polyolefin content, 10%-90% PET content, 1%-25% polystyrene content, and 1% to
50%
unknown polymer content. Such mixed plastic streams and waste plastic streams,
not
limited to those collected from oceans and beaches, are similarly usefully to
form molten
polymer foams and polymer foam articles using the methods and apparatuses
described
herein. Example 11 shows the use of a mixed stream ocean waste plastic source
having
20% recycled content.
1001691 Further, we have found that the polymer foam articles made in
accordance
with the methods described herein may be recycled using the methods described
herein.
39
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
That is, in embodiments, a first polymer foam article in accordance with any
of the
embodiments described herein, and formed in accordance with any of the methods
described herein, is also a source of thermoplastic polymer for forming a
second polymer
foam article in accordance with the methods described herein. In embodiments,
the
polymer foam articles described herein are suitably recycled employing any of
the
methods described herein for making a polymer foam article. Thus, a polymer
foam
article may be recycled, for example, by simply grinding a first polymer foam
article
made in accordance with the methods described herein, or otherwise dividing it
into
pieces of suitable size for direct use in a melt mixing apparatus; and
applying the divided
first polymer foam article to a melt mixing apparatus. The melt mixing
apparatus may be
an injection molding machine or an extruder. Where the melt mixing apparatus
is an
injection molding machine, a second polymer foam article may be formed by
carrying out
any of the methods described herein for forming a polymer foam article,
employing the
divided first polymer foam article as the feedstock or source of polymer. In
this manner,
mixed feedstocks may also be used, such as mixed sources of divided polymer
foam
articles (different thermoplastics, additives, and the like); or mixtures of
divided polymer
foam articles with other plastic materials such as virgin or used plastic
sources.
1001701 The foregoing recyclability of the polymer foam articles is observed
over a
range of polymeric materials including but not limited to low-density
polyethylene
(LDPE), high-density polyethylene (11DPE), polypropylene (PP), high-impact
polystyrene (HIPS), polyethylene terephthalate (PET), polybutylene
terephthalate (Pal),
polyanaide (PA), thermoplastic polyurethane (TPU), and thermoplastic olefin
(TP0). The
recyclability is observed for single component polymer foams, blends of
polymers with
additives including any of the additives listed herein, and mixtures and
blends of two or
more polymers. Example 16 exemplifies this surprising and unexpected outcome.
Due
to the difficulty of using 100% recycled thermoplastic materials for processes
such as
extrusion and injection molding, the plastics industry typically supplies
mixed plastic
waste streams for industrial recycling use, and thus recycled plastic articles
often include
only a fraction of recycled materials mixed with virgin plastics, such as
between 10% and
50% recycled plastic by weight or by volume. However, using the methods
described
herein, 100% recycled plastic material may be used to make the polymer foam
articles
described herein. Further, 100% virgin thermoplastics may be used to make the
polymer
foam articles described herein, as well as mixtures of recycled and virgin
material
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
feedstocks. and the polymer foam articles formed from these feedstocks are
100%
recyclable in a subsequent injection molding or extrusion process.
[00171] Pneumatogen sources are widely available in the industry and
conditions
usefiil to deploy pneumatogens during melt mixing are well understood and
broadly
reported. Accordingly, any pneumatogen source useful for injection molding,
reaction
injection molding, or other methods of making of polymer foams, is useful
herein to form
the molten polymer foams and solidified polymer foam articles in accordance
with the
methods, apparatuses, and polymer foam articles described herein. Pneumatogens
useful
in connection with the methods and apparatuses described herein include air,
CO2, and
N2, either as encapsulated within a thermoplastic in the form of beads,
pellets, and the
like or in latent form, wherein a chemical reaction generates CO2 or N2 when
heated
within the melt mixing apparatus. Such chemical reactions are suitably
exothermic or
endothermic without limitation regarding their use in conjunction with the
methods and
apparatuses disclosed herein. Suitable pneumatogen sources include sodium
bicarbonate,
compounds based on a polycarboxylic acid such as citric acid, or a salt or
ester thereof
such as sodium citrate or the trimethyl ester of sodium citrate; mixtures of
sodium
bicarbonate with a polycarboxylic acid such as citric acid; sulfonyl
hydrazides including
p-toluene sulfonyl hydmzide (p-TSH) and 4,4'-oxybis-(benzenesulfonyl
hydrazide)
(OBSH), pure and modified azodicarbonamides, semicarbazides, tetrazoles, and
diazinones. In any of the foregoing, the pneumatogen source is optionally
further
encapsulated in a carrier resin designed to melt during the heating, mixing,
and collection
of a shot.
1001721 In embodiments, useful pneumatogen sources include commercially
available
compositions such as HYDROCEROL BIH 70, HYDROCEROL BIH CF-40-T, or
HYDROCEROL X.H-901, all available from Clariant AG of Switzerland; FCX 7301,
available from RIP Company of Winona, MN; FCX 27314, available from RTP
Company of Winona, MN; CELOGEN 780, available from CelChem LLC of Naples,
FL; ACTAFOAM 780, available from Galata Chemicals of Southbury, CT;
ACTAFOAM AZ available from Galata Chemicals of Southbury, CT; ORGATER
MB.BA.20, available from ADEKA Polymer Additives Europe of Mulhouse, France;
ENDEX 1750Tm, available from Endex International of Rockford, IL; and
FOAMAZOLTm 57, available from Bergen International of East Rutherford, NJ.
41
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
100173] in some embodiments, the pneumatogen source is a pneumatogen, wherein
the
pneumatogen is applied as a gas to a melt mixing apparatus, such as an
apparatus similar
to the extruder shown in FIGS 1A-1B. In such embodiments the gas is caused to
dissolve
within the thermoplastic polymer by direct pressurized addition to and mixing
within the
melt mixing apparatus. In some embodiments the gas becomes a supercritical
fluid by
pressurization, either prior to or contemporaneously with dissolution into the
molten
thermoplastic polymer. Applying a pneumatogen directly to an injection molding
apparatus is referred to industrially as the MUCELL process, as employed by
Trexel
Inc. of Wilmington, DE. Specialized equipment is required for this process,
such as a
regulated, pressurized fluid connection from a gas reservoir (tank, cylinder
etc.) to the
inlet of an extruder apparatus to form a pressurized relationship with the
barrel as the
thermoplastic polymer is also added to the barrel and melted. Where such
specialized
equipment is available, a pneumatogen is usefully employed as the pneumatogen
source
in conjunction with the methods described he by direct application of the
pneumatogen to the thermoplastic polymer and one or more additional materials
to form
a molten pneumatic mixture.
[001741 The pneumatogen source is added to the thermoplastic polymer, and any
optionally one or more additional materials, in an amount that targets a
selected density
reduction of the thermoplastic polymer, in accordance with conventional art
associated
with desirable polymer foam density and operation of pneumatogens and
pneumatogen
sources to form thermoplastic polymer foams. The amount of the pneumatogen
source
added to th.c thermoplastic polymer is not particularly limited; accordingly,
we have
found that up to 85% density reduction is achieved without the use of polymer
or glass
bubbles or the like, to provide a polymer foam article having the unique and
surprising
characteristics reported below and further having a targeted density reduction
of up to
85%. As used herein, "density reduction" means a percent mass reduction in a
polymer
foam article compared to the same article without adding a pneumatogen
(source) to
make the article (that is, a polymer article excluding or substantially
excluding
pneumatoceles). Thus, in embodiments the molten polymer foarn.s and the
polymer foam.
articles described herein suitably exclude glass or polymer bubbles, while
providing a
selected density reduction of up to 85%, for example 30% to 85%, such as 35%
to 85%,
40% to 85%, 45% to 85%, 50% to 85%, 55% to 85%, 60% to 85%, 65% to 85%, 70% to
85%, 75% to 85%, 30% to 35%, 35% to 40%, 40% to 50%, 50% to 55%, 55% to 60%,
42
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
60% to 65%, 65% to 70%, 70% to 75%, 75%, to 80%, or 80% to 85%. Including
glass or
polymer bubbles further extends the available density reduction of a polymer
foam article
made in accord with the methods herein. In some embodiments greater than 85%
density
reduction may be achieved.
[001751 The polymer foam articles benefitting from the density reduction
nonetheless
are characterized as having a continuous polymer matrix throughout with
pneumatoccles
dispersed therein, including molded articles having a shape and a volume
wherein a
theoretical sphere, such as a glass or metal ball or marble, having a diameter
of 2 cm
would fit within the polymer foam article in at least one location, without
protruding
from the surface. In embodiments, the polymer foam articles have a shape and a
volume
wherein a sphere having a diameter of 2 cm - 1000 cm or more would fit within
the
polymer foam article in at least one location, without protruding from the
surface. In
embodiments, the polymer foam articles have a shape and a volume wherein a
sphere
having a diameter of 2 cm - 1000 cm would fit within the polymer foam article
in at least
one location, without protruding from the surface and further have a total
article volume
greater than 1000 cm', a volume of at least 2000 cm', a volume between 1000
cm' to
5000 cm3, a volume between 2000 cm' to 5000 cm', or a volume of more than 5000
cm'.
The shape of the polymer foam article is not limited and may generally be
cuboid,
spheroid, toroid, or any other shape desired.
1001761 As mentioned above, the amount of the pneumatogen source added to the
thermoplastic polymer is not particularly limited; accordingly, we have found
that up
85% of the total volume of a polymer foam article comprises pneumatoceles. The
total
volume of the pnetunatoceles as a percent of the total volume of the polymer
foam article
is referred to as the -void fraction" of the article; thus, void fraction of
up to about 85% is
achieved without including polymer or glass bubbles or the like, to provide a
polymer
foam article having the unique and surprising characteristics reported below
and further
having a targeted void fraction of up to 85% of the volume of the polymer foam
article.
Thus, in embodiments the molten polymer foams and the polymer foam articles
described
herein suitably exclude glass or polymer bubbles, while providing a void
fraction of up to
85%, for example 5% to 85%, such as 10% to 85%, 15% to 85%, 20% to 85%, 25% to
85%, 30% to 85%, 35% to 85%, 40% to 85%, 45% to 85%, 50% to 85%, 55% to 85%,
60% to 85%, 65% to 85%, 70% to 85%, 75% to 80%, 80% to 85%, 5% to 10%, 10% to
15%, 15% to 20%, 20% to 25%, 25% to 30%, 30% to 35%, 35% to 40%, 40% to 50%,
43
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
50% to 55%, 55% to 60%, 60% to 65%, 65% to 70%, 70% to 75%, 75% to 80%, or 80%
to 85%. Including glass or polymer bubbles further extends the available void
fraction of
a polymer foam article made in accord with the methods herein. In some
embodiments
greater than 85% void fraction may be achieved. The polymer foam articles
having 85%
void fraction are nonetheless are characterized as having a continuous polymer
matrix
throughout with pneumatoceles dispersed therein, including molded articles
having a
shape and a volume wherein a sphere having a diameter of 2 cm ¨ 1000 cm would
fit
within the polymer foam article in at least one location, without protruding
from the
surface and further have a total article volume greater than 1000 cm", a
volume of 2000
cm' or more, a volume between 1000 cm' to 5000 cm3, a volume between 1000 cm'
and5000 cm3., or between 12000 cm3 and5000 cm3, or a volume greater than 5000
cm3.
1001.771 In some embodiments, the thermoplastic polymer and a pneumatogen
source
arc admixed prior to applying the admixture to a melt mixing apparatus for
heating and
mixing. In other embodiments, the thermoplastic polymer and a. pneumatogen
source are
added separately to a melt mixing apparatus, such as by two different inlets
or ports
available for adding materials to the melt mixing apparatus. In still other
embodiments,
a solid mixture including both a thermoplastic polymer and a pneumatogen
source are
added as a single input to a melt mixing apparatus for heating and mixing.
100178i In embodiments, one or more additional materials are included or added
to a
melt mixing apparatus along with the thermoplastic polymer and pneumatogen
source;
such additional materials are suitably mixed or admixed with the thermoplastic
polymer,
the pneumatogen source, or both; or the one or more additional materials are
added
separately, such as by in individual port or inlet to a melt mixing apparatus.
Examples of
suitable additional materials include colorants (dyes and pigments),
stabilizers,
brighteners, nucleating agents, fibers, particulates, and fillers. Specific
examples of some
suitable materials include talc, titanium dioxide, glass bubbles or beads,
thermoplastic
polymer particles, fibers, beads, or bubbles, and thermoset polymer particles,
fibers,
beads, or bubbles. Additional examples of suitable materials include fibers
such as glass
fibers, carbon fibers, cellulose fibers and fibers including cellulose,
natural fibers such as
cotton or wool fibers, and synthetic fibers such as polyester, polyarnide, or
ararnid fibers;
and including microfibers, nanofibers, crimped fibers, shredded or chopped
fibers, phase-
separated mixed fibers such as bicomponent fibers including any of the
foregoing
mentioned polymers, and thermosets formed from any of the foregoing polymers.
44
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
Further examples of suitable additional materials are waste materials, further
shredded or
chopped as appropriate and including woven or nonwoven fabrics, cloth, or
paper; sand,
gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates;
and other
biological, organic, and mineral waste streams and mixed streams thereof.
Further
examples of suitable additional materials are minerals such as calcium
carbonate and
dolomite, clays such as montmorillonite, sepiolite, and bentonite, micas,
wollastonite,
hydromagnesite/huntite mixtures, synthetic minerals, silica agglomerates or
colloids,
aluminum hydroxide, alumina-silica composite colloids and particulates,
Halloysite
nanotubes, magnesium hydroxide, basic magnesium carbonate, precipitated
calcium
carbonate, and antimony oxide. Further examples of suitable additional
materials include
carbonaceous fillers such as graphite, graphene, graphene quantum dots, carbon
nanotubes, and C60 buckeyballs. Further examples of suitable additional
materials
include thermally conductive fillers such as boronitride (BN) and surface-
treated BN.
1001791 In embodiments, one or more additional materials are included or added
to a
melt mixing apparatus along with the thermoplastic polymer and pneumatogen
source in
an amount of about 0.1% to 50% of the mass of the thermoplastic polymer, for
example
0.1% to 45%, 0.1% to 40%, 0.1% to 35%, 0.1% to 30%, 0. I% to 25%, 0.1% to 20%,
0.1% to 15%, 0.1% to 10%, 0.1% to 9%, 0.1% to 8%, 0.1% to 7%, 0.1% to 6%, 0.1%
to
5%, 0..1% to 4%, 0.1% to 3%, 0.1% to 2%, 0..1% to 1%, 1% to 50%, 2% to 50%, 3%
to
50%, 4% to 50%, 5% to 50%, 6% to 50%, 7% to 50%, 8% to 50%, 9% to 50%, 10% to
50%, 11% to 50%, 12% to 50%, 13% to 50%, 14% to 50%, 15% to 50%, 20% to 50%,
25% to 50%, 30% to 50%, 35% to 50%, 40% to 50%, 45% to 50%, 0.1% to 2%, 2% to
5%, 5% to 10%, 10% to 15%, 15% to 20%, 20% to 25%, 25% to 30%, 30% to 35%, 35%
to 40%, 40% to 45%, or 45% to 50% of the mass of thermoplastic polymer added
to the
melt mixing apparatus to form a shot.
1001.801 Accordingly, in melt mixing apparatuses that are not extruders, it
will be
understood by one of skill that the following method will result in a molten
polymer foam
possessing the significant technical benefits described in sections below. A
method of
forming and collecting a molten polymer foam includes the following: heating
and
mixing a thermoplastic polymer and a pneumatogen source to form a molten
pneumatic
mixture, wherein the temperature of the molten pneumatic mixture exceeds the
critical
temperature of the pnetunatogen source and a pressure applied to molten
pneumatic
mixture is sufficient to substantially prevent formation of pneumatoceles;
collecting a
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
selected amount of the molten pneumatic mixture in a collection area; defining
an
expansion volume in the collection area proximal to the molten pneumatic
mixture that
results in a pressure drop; maintaining the expansion volume for an expansion
period of
time; and collecting a molten polymer foam from the collection area. In
embodiments,
the molten pneumatic mixture is undisturbed or substantially undisturbed
during the
expansion period. In embodiments, defining the expansion volume is
accomplished at a
rapid rate of depressurization (that is, the rate of defining the pressure
drop) which is at
least 0.01 GPa/s, in embodiments 0.1 GPa/s or greater; and in some embodiments
is 1.0
OPa/s or even greater, such as up to 5.0 GPa/s; or 0.01 GPa/s to 5.0 GPa/s, or
or 0.1
GPais to 5.0 GPa/s, or 1 GPa/s to 5.0 GPa/s, or 0.01 GPa/s to .0 GPa/s, or
0.01 GPa/s to
3.0 GPa/s, or 0.01 GPa/s to 2.0 GPa/s, or 0.01 GPa/s to 1.0 GPa/s, or 0.01
GPa/s to 0,1
GPa/s, or 0.1 GPa/s to .1.0 GPais, or 1.0 GPa/s to 2.0 GPa/s, or 2.0 GPals to
3.0 GPa/s, or
3.0 GPa/s to 4.0 GPa/s, or 4.0 GPa/s to 5.0 GPa/s. In some such embodiments,
rapid
depressurization is coupled with a high backpressure, that is, a backpressure
of 500 kPa
or greater, such as a backpressure of 500 kPa to 25 MPa, or 1 MPa to 25 MPa,
or 2 MPa
to 25 MPa, or 3 MPa to 25 MPa, or 4 MPa to 25 MPa, or 5 MPa to 25 MPa, or 6
MPa to
25 MPa., or 7 MPa to 25 MPa, or 8 MPa to 25 MPa, or 9 MPa to 2 MPa, or 10 MPa
to 25
MPa, or 500 kPa to 20 MPa, or 500 kPa to 15 MPa, or 500 kPa to 12 MPa, or 500
kPa to
MPa, or 500 kPa to 9 MPa, or 500 kPa to 8 MPa, or 500 kPa to 7 MPa, or 500 kPa
to 6
MPa, or 500 kPa to 5 MPa, or 500 kPa to 4 MPa, or 500 kPa to 3 MPa, or 500 kPa
to 2
MPa, or 500 kPa to 1 MPa, or 1 MPa to 5 MPa, or 5 MPa to 10 MPa.
1001811 In embodiments, by using the methods described herein, and employing
rapid
depressurization of the molten pneumatic. mixture in the collection area, and
in
embodiments further employing high backpressure to initiate the rapid
depressurization, a
stabilized molten polymer foam is obtained that requires no expansion period
or requires
a shortened expansion period of 0 to 5 seconds such as 0-1 second, 1-2
seconds, 2-3
seconds, 3-4 seconds, or 4-5 seconds to provide a molten polymer foam capable
of
forming the polymer foam articles described herein, including articles having
a shape and
a volume wherein a sphere having a diameter of 2 cm. ¨ 1000 cm, that is,
including 20 cm
and above, would fit within the polymer foam article in at least one location,
without
protruding from the surface; and further have a total article volume greater
than 1000
cm3, a volume of 2000 cm3 or more, or a volume between 1000 cm3 and 5000 cm3,
between 2000 cm3 and 5000 cm3, or a volume greater than 5000 cm3.
46
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1001821 In some embodiments, collecting the molten polymer foam includes
applying
the molten polymer foam to a cavity defined by a mold; and cooling the molten
polymer
foam below a melt temperature of the thermoplastic polymer to obtain a polymer
foam
article. In embodiments where the molten polymer foam is applied to the cavity
of a
mold, the cooled polymer foam article obtains the shape and dimensions of the
mold,
further wherein polymer foam is characterized as a continuous polymer matrix
having
pneumatoceles distributed throughout the entirety of the article. In
embodiments, the
molten polymer foam is applied to a mold cavity by allowing the molten polymer
foam to
flow and enter a mold cavity by gravitational force; in some such embodiments
the flow
is unimpeded and is allowed to fall into an open cavity. In other embodiments,
the
molten polymer foam is applied under pressurized flow to a forming element. In
embodiments the molten polymer foam is delivered to a mold cavity by fluid
connection
thereto from a nozzle or other means of delivery of molten polymer foam from a
collection area of a melt mixing apparatus.
1001831 For example, in embodiments, an extruder is adapted and designed to
dispense
a molten mixture from an outlet into a forming element, which is a mold
defining a cavity
therein, and designed and adapted to receive a molten polymer mixture, such as
a molten
pneumatic mixture. In embodiments the forming element is a mold configured and
adapted to receive a molten thermoplastic polymer dispensed from an outlet,
further
wherein a mold is characterized as generally defining a void or cavity having
the selected
shape and dimensions of a desired article.
1001841 In embodiments, dispensing from an. extruder is accomplished by
mechanical.
plunging, by applying a gaseous pressure from within the barrel of the
extruder, or a
combination thereof. In other embodiments, an outlet, valve, gate, nozzle, or
door to the
collection area is simply opened after the expansion period has passed, and
the molten
polymer foam is allowed to flow unimpeded through the outlet; the molten flow
is then
directed to a cooling or other processing apparatus, or the molten flow is
allowed to pour
into a forming element. In other embodiments, the forming element is fluidly
connected
to the outlet and is further designed and adapted to be filled with a molten
mixture so that
the molten mixture obtains a selected shape when cooled and solidified. In
some
embodiments, the forming element is fluidly cormected to the extruder outlet
such that a
pressure is maintained between the collection area, the outlet, and the
forming element or
mold. Any conventional thermoplastic molding or forming process associated
with
47
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
injection molding of polymer articles, such as polymer foam articles, is
suitably
employed to mold the molten polymer foams described herein.
[00185] In some embodiments, the molten polymer foam is allowed to flow
unimpeded through the outlet, or is plunged under a pressure from the outlet
without
further impedance of flow, the molten flow eventually impinges on a surface,
such as a
surface generally perpendicular to the direction of the molten flow. We have
observed
that the flow under such circumstances then obtains a generally cylindrical
(coiling) and
planar (folding) pattern during continued molten flow, such as reported by
Batty and
Bridson, "Accurate Viscous Free Surfaces for Buckling, Coiling, and Rotating
Liquids"
Symposium on Computer Animation , Dublin, July 2008.
[00186] In embodiments, the molten polymer foam is dispensed into a mold
cavity,
followed by cooling the molten polymer foam to a temperature below a melt
transition of
the thermoplastic polymer, to obtain a solidified polymer foam article. In
embodiments,
the molten polymer foam is allowed to flow, or is "poured" unimpeded from the
outlet of
a melt mixing apparatus and into a mold that is configured as an open
container. In
embodiments the open container mold is completely filled with molten polymer
foam; in
other embodiments the open container mold is partially filled with molten
polymer foam.
In other embodiments, the molten polymer foam is dispensed by plunging, or
urging the
screw of the extruder laterally in a direction toward the nozzle.
[00187] During the dispensing of the molten polymer foam into a mold cavity,
the
molten polymer foam flows into the mold cavity and contacts the cavity
surface, and then
proceeds to fill the mold cavity. In embodiments, the dispensing includes
partially filling
the mold cavity with molten polymer foam, wherein 50% or less of the mold
cavity
volume is occupied by the molten polymer foam, such as 1% to 50%, or 5% to
50%, or
10% to 50%, or 20% to 50%, or 30% to 50%, or 40% to 50%, or 1% to 40%, or 1%
to
30%, or 1% to 20%, or 1% to 10%, or 1% to 5% of the mold cavity volume is
occupied
by the molten polymer foam after the dispensing. In other embodiments the
dispensing
includes substantially filling the mold cavity with molten polymer foam,
wherein 50% to
99.9% of the mold cavity volume is occupied by the molten polymer foam, such
as 50%
to 99.5%, or 50% to 99%, or 50% to 98%, or 50% to 97%, or 50% to 96%, or 50%
to
95%, or 95% to 99.9%, or 96% to 99.9%, or 97% to 99.9%, or 98% to 99.9%, or
99% to
99.9%, or 99.5% to 99.9% of the mold cavity volume is filled with the molten
polymer
foam after the dispensing. In still other embodiments, the dispensing includes
48
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
completely filling the mold cavity with molten polymer foam, wherein 100% of
the mold
cavity is occupied by the molten polymer foam after the dispensing.
[001881 In some embodiments related to the molten flow described above, a
coiled
molten flow substantially free of shear, or a substantially linear molten flow
is provided
by fluid connection between the outlet of the extruder and into a mold cavity.
In some
such embodiments, the molten flow may obtain a coiled molten flow, either by
impinging
on a perpendicular surface thereof or by flowing down a substantially vertical
wall or side
of a mold cavity and collecting at the bottom of the mold cavity. A schematic
representation of one such an embodiment is shown in FIG. 4 L which shows a
variation
of the extruder of FIGS 1A-1B wherein mold 26 of apparatus 20 is situated on a
substantially horizontal surface 100. In reference to elements as shown in
FIGS. IA -18,
there is no shutoff valve 37 at distal end 21b of barrel 21; instead, in FIG.
41, collection
area 40 extends to a mold valve 137 situated proximal to mold cavity 39
defined within
mold 26. Thus, mold valve 137 is operable to define collection area 40, or to
provide an
outlet for dispensing a molten polymer foam to mold cavity 39 via a
substantially linear
horizontal flow 110. Mold valve 137 is situated a height IT above horizontal
surface 100,
and a height H2 above the floor or bottom 120 of mold 26 as situated on
horizontal
surface 100. In reference to FIG. 41, mold valve 137 is selectively opened to
provide
fluid connection between collection area 40 and mold cavity 39. Thus, mold
valve 137 is
selectively opened to provide a substantially linear horizontal flow 110 of
molten
polymer foam entering mold cavity 39. Upon entering mold cavity 39, the linear
flow
flows downward over the distance H2, and in some embodiments obtains a coiled
molten
flow as it proceeds to fill mold cavity 39. Other related variations of the
methods and
apparatuses are contemplated to provide a coiled molten flow as described
herein.
1001891 In embodiments, upon cooling and removing a polymer foam article from
an
open container or a mold situated such as shown in FIG. 41, the coiling and
folding flow
pattern is visible at the surface of the article. An example of such a visible
flow pattern
may be seen in e.g. FIGS. 2-2 and 2-4. Upon cryogenic fracturing and
microscopic
inspection of the interior of polymer foam articles formed using the coiled
and folding
flow, the interior of the article is free of or substantially free of flow
patterns, interfaces,
or other evidence of coils and folds. For example, cryogenic fracturing of
such polymer
foam articles does not result in fracturing at any discernible interface
between coils and
folds; and both macroscopic and microscopic inspection of the interior of such
polymer
49
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
foam articles obtains a homogeneous appearance with respect to flow patterns.
The
physical properties of such polymer foam articles are consistent with the
physical
properties obtained by subjecting the molten polymer foam to a directed fluid
flow, via
fluid connection between an outlet of a melt mixing apparatus and a mold, or
subjecting
the molten polymer foam to pressurized directed fluid flow.
100190j In some embodiments, the methods herein include partially,
substantially, or
completely filling a mold with the molten polymer foam formed in accordance
with the
foregoing described methods, then cooling the molten polymer foam to form a
solidified
polymer foam; and in embodiments further removing the solidified polymer foam
article
from the mold. in embodiments, the molten polymer foam is a stabilized molten
polymer
Foam, hi embodiments, the cooling is cooling to a temperature below a melt
transition of
the thermoplastic polymer. In embodiments, the cooling is cooling to a
temperature in
equilibrium with the ambient temperature of the surrounding environment. In
some
embodiments the mold further includes one or more vents for pressure
equalization in the
mold during filling thereof with molten polymer foam, but in other embodiments
no vents
are present. After cooling, a polymer foam article may be removed from the
mold for
further modification or use.
[001911 In some embodiments, after the cooling of the molten polymer foam to
form a
solidified polymer foam article, and removal of the polymer foam article from
the mold,
the polymer foam continues to expand after removal of the polymer foam article
from the
mold. That is, the polymer foam article expands after removal of the article
from the
mold, and the density of the article decreases as a result of the post-mold
expansion.
[001921 In accord with any of the fbregoing description, Table I provides
useful but
non-limiting examples of processing conditions employed to make a molten
polymer
foam using a conventional single screw extruder type reaction injection
molding
apparatus, further by employing one or more representative thermoplastic
polymers and a
citric acid-based pneumatogen source as indicated.
1001931 Table I . Representative thermoplastic polymers and conditions useful
for
making and molding molten polymer foams.
CA 03223228 2023- 12- 18
WO 2023/277935 PCT/1J52021/049200
, ................
I ............................................................................
----
.si..
.: 11
.1.4
I , , R . P 4 '4; '' 2 Z :-...t ..
!:.Ã Ã 4. .,== ft, se. Si :=:: F". W.
.....t. ,...4. 4g, ,... .7.=:: ':...... ( N,
..,', 2...." I .=',
i17-1 =.;<,
.0:
. .
.õ,.
.04 ... ¨
0 ...g
= 4,--, m ,th r= t ", e-: i...1 t- 4 .--
'.:' r's
,;-
7-I
.., e.
g I
................................. i
i 4 .......................................
i
;
A ii -0
rt i :.--=::. I k =if,..$ 0, .': ...::. ::0, -5.,.
.., :ff: :Ft,. -, ,-, ..: ..,
n ..., =ti. ..... cp:
r..N OD. i SO gif
C4
1
S ................................ 4 .. 4 ....................................
I
Ib
ES
A c,3 ...: :::: ," .... õ ..õ. .... _ ,., =.,C =ft
Ci= ...... v...; = ' ...,... 2.4
tir,
E 1
.4
I a ''' ...,
1 ___________________________________ .............._ -== I.
..
-4.
el-
Va
.1 ...V
11 1.:: .F el =,.t. ,. -r -4.
te ... ... _ r .., ,= .-: = =.::: <.;.
di
* to V 4 To
4 ....... tb, A
k ¨
r... ==== :...: C.. 1,..?
r = , ,,
.-,
1... 4 c..1
get -..' 7,,'F. fr:
sa...= ft;. ,i,..
4
..,
___________________________________________________________________ i _
:-V * A .-z s2 =,-, f..1 .s. ¨ ¨ ..:-.4 -,...,-; sn. a e-..--:: 4*
t ..g= .......
..., .....
= gt.
a.. ________ -
a ,
.....,
ii
.....
e
"i ze
I
CS 2
A t=-= 4. = r V
t IT :a
a"
4.-
V
11 t... m 1 1
.i.., I I 1 g = =,':-.: if- 1 :v.. .. 7.; 1 r- Z.,
os
43
Lit
___________________________________________________ - ¨ .. I ..............
I
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1001941 In embodiments, the dimensions of molds usefully employed to form the
polymer foam articles made using the methods, and materials disclosed herein
include
molds that define cavities that may be filled by a single shot of molten
polymer foam, or
a series of cavities that may be filled by a single shot of molten polymer
foam. As such,
the size of the mold cavity is limited only by the size of the shot that can
be built in the
melt mixing apparatus employed by the user. Representative mold cavities
having
volumes of up to I x10 cm' are useful for making large parts such as
automobile cabin or
exterior parts, I-beam construction parts, and other large plastic items
suitably employing
a polymer foam. Further, the shape of the mold cavities are not particularly
limited and
may be complicated in terms of overall shape and even surface patterns and
features, for
example shapes recognizable as dumbbells, tableware, ornamental globes with
raised
geographical features, human or animal or insect shapes, framework or
encasement
shapes for framing or encasing e.g. electronic articles, appliances,
automobiles, and the
like, shapes for later disposing and fitting screws, bolts, and other non-
thermoplastic
items into or through the polymer foam article; and the like are all suitable
mold shapes
for molding a polymer foam article as described herein. in some embodiments
the cavity
includes a thickness gradient of up to 300% as to one or more regions of the
cavity.
1001951 In accord with any of the foregoing description, Table 2 provides
useful but
non-limiting examples of mold cavity volumes and dimensions of molds useful to
mold
the molten polymer foams, either by pressurized flow or by unimpeded flow of
the
molten polymer foam. into the mold. Additionally, larger mold volumes, such as
up to
100,000 cm' or larger are useful where shot mass is suitably increased.
[001961 Table 2. Representative mold cavity volumes and dimensions useful to
mold
the molten polymer foams.
Part Cavity Volume (cc)
3" diameter sphere 231.00
6" diameter sphere 1,856.66
9" diameter sphere 6,243.47
18" diameter sphere 50,038.52
'buck Body 4,771.10
[buck 1-lead 812.80
12"x12"xl." Plate 2,359.74
4"x4"x2" Brick 545.69
52
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
õ _____________________________________________
k1-"x1-" Block 1.091.38
1-
r__ -------------------------------
ii2i 2" x 12" Block _IF . 28,316.84
117"x41xl" Plate ______________ ,114.32
[11"x4"x2" Plate _____________________________________ 1,442.06
2"x2"x0.5" Plate 32.77
2"N2"x2" Block 131.10
2.625"x5.625"x1" Plate 241.97
11"x I"x2" Plate 32.77
1001971 Any the methods, processes, uses, machines, apparatuses, or individual
features thereof described above are freely combinable with each other to form
polymer
foams and polymer foam articles having unique and surprising characteristics.
Thus, in
embodiments, a polymer foam article is formed using the foregoing described
methods,
materials, and apparatuses. The polymer foam article is a discrete, monolithic
object
made by forming or molding a molten polymer foam in accordance with any of the
methods and materials disclosed above as well as variations thereof which are
combinable in any part and in any manner to form a molten polymer foam as
described
above.
1001981 Accordingly, terminology used to refer to the methods, materials, and
apparatuses in the foregoing discussion are used below to refer to articles
made using one
or more methods, materials, and apparatuses encompassed in the foregoing
discussion.
1001991 In embodiments, any combination of the foregoing methods results in
formation of a polymer foam article comprising, consisting essentially of, or
consisting of
a continuous thermoplastic polymer matrix defining a plurality of
pneumatoccles. The
continuous thermoplastic polymer matrix comprises, consists of, or consists
essentially of
a solid thermoplastic polymer, that is, the thermoplastic polymer is present
at a
temperature below a melt transition thereof. In embodiments, the continuous
thermoplastic polymer matrix further includes one or more additional materials
dispersed
in the solid thermoplastic polymer.
1002001 The polymer foam articles obtain density reductions, based on the
density of
the thermoplastic polymer and any other materials added to form the polymer
foam, of a
selected percent based on the amount of pneumatogen source added to the shot.
In
embodiments, a density reduction of 30%, 40%, 50%, 60%, 70% and even up to 80%
to
85% density reduction, as selected by the user. In embodiments, up to 85%
density
53
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
reduction is achieved solely by the presence of pneumatoceles distributed
discontinuously
in the polymer matrix. In embodiments, the polymer foam articles exclude
hollow
particulates such as polymer or glass bubbles added to the shot prior to
forming the
polymer foam article using the methods and apparatuses described herein.
1002011 Further in conjunction with reduced density, as mentioned above the
polymer
foam articles herein arc characterized as having a continuous thermoplastic
polymer
matrix throughout the entirety thereof or substantially throughout the
entirety thereof.
We have found that very large polymer foam articles may be suitably formed
from the
molten polymer foams disclosed herein to include a continuous polymer matrix
defining
a plurality of pneumatoceles. "Large polymer foam articles" are those having a
shape
and a volume wherein a sphere having a diameter of 20 cm would fit within the
article in
at least one location, without protruding from the surface. In some
embodiments, a
"large polymer foam article" has a shape and a volume wherein a sphere having
a
diameter of 20 cm would fit within the polymer foam article in at least one
location,
without protruding from. the surface, and further has a total volume of 1000
cm3 or more,
for example 2000 cm3 or more, 3000 cm3 or more, 4000 cm3 or more, or 5000 cm3
or
more, or any volume between 1000 cm' and 5000 cml; or between 2000 CIT13 and
5000
cm3 and including volumes up to 10,000 cm3, up to 20,000 cm3, up to 50,000
cm3, or
even up to 100,000 cm3 or greater.
1002021 Large polymer foam articles may be suitably formed from stabilized
molten
polymer foam to include a continuous polymer matrix defining a plurality of
pneumatoceles throughout the entirety thereof. The volume of the article is
limited only
by the size of the mold cavity and the size of the shot that can be collected
in the melt
mixing apparatus. In embodiments, a large article is formed from a single shot
dispensed
from a single outlet of a melt mixing apparatus, that is, without splitting of
the molten
polymer foam flow to multiple simultaneous distribution pipes, nozzles, or
other methods
of directing multiple molten streams simultaneously into a single mold cavity.
1002031 Additionally, we have found that thick polymer foam articles may be
suitably
formed to include a continuous polymer matrix defining a plurality of
pneumatoceles.
Thickness as used herein refers to straight line distance through the interior
of a polymer
foam article between any two points on the surface thereof. "Thick" articles
are defined
as having a thickness of 2 cm or more, such as 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8
cm, 9 cm,
cm, 15 cm, 20 cm, 25 cm, 30 cm, 35 cm, 40 cm., 45 cm., or even 50 cm or more.
In
54
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
some embodiments, a polymer foam article is formed using the methods and
materials
described herein that is characterized as being both large and thick, further
wherein the
large, thick polymer foam article is nonetheless characterized as having a
continuous
polymer matrix defining a plurality of pneumatoceles throughout the article.
In
embodiments, a large, thick article is formed from a single shot dispensed
from a single
outlet of a melt mixing apparatus, that is, without splitting of the molten
polymer foam
flow to multiple simultaneous distribution pipes, nozzles, or other methods of
directing
multiple molten streams simultaneously into a single mold cavity.
1002041 In embodiments, the polymer foam articles formed using the methods
described herein have a shape and a volume wherein a (theoretical) sphere
having a
diameter of 2 cm would fit within the polymer foam article in at least one
location,
without protruding from the surface of the article. In some embodiments, the
polymer
foam articles include a shape and a volume wherein a (theoretical) sphere
having a
diameter of greater than 2 cm would fit within the polymer foam article in at
least one
location, without protruding from the surface of the article. In embodiments,
the polymer
foam articles have a shape and a volume wherein a (theoretical) sphere having
a diameter
of 2 cm to 1000 cm would fit within the polymer foam article in at least one
location,
without protruding from the surface of the article; for example, in one or
more
embodiments, a (theoretical) sphere having a diameter of 3 cm, 4 cm, 5 cm, 6
cm, 7 cm, 8
cm, 9 cm, 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, 15 cm, 16 cm, 17 cm, 18 cm, 19
cm, 20
cm, 25 cm, 30 cm, 35 cm, 40 cm, 45 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, 100
cm,
200 cm, 300 cm, 400 cm, 500 cm, 600 cm, 700 cm, 800 cm, 900, 1000 cm, 3 cm-4
cm., 5
cm-6 cm, 7 cm-8 cm, 9 cin-10 cm, 11 cm-12 cm, 13 cm-14 cm, 15 cm-16 cm, 17 cm-
18
cm, 19 cm-20 cm, 20 cm-25 cm, 25 cm-30 cm, 30 cm-35 cm, 35 cm-40 cm, 40 cm-45
cm, 45 cm-50 cm, 50 cm-60 cm, 60cm-70 cm, 70 cm-80 cm, 80 cm-90 cm, 90 cm-100
cm., 100 cm-200 cm, 200 cm-300 cm, 300 cm-400 cm, 400 cm.-500 cm., 500 cm-600
cm,
600 cm-700 cm, 700 cm-800 cm, 800 cm-900, or even 900 cm-1000 cm would fit
within
the polymer foam article in at least one location, without protruding from the
surface of
the article. In embodiments, the polymer foam articles formed using the
methods
described herein have a shape and a volume wherein two or more (theoretical)
spheres
having a diameter of 2 cm would fit within the polymer foam article without
overlapping,
and without any of the spheres protruding from the surface of the article. For
example, 2,
3, 4, 5, 6, 7, 8, 9, 10, 10-15, 15-20, 20-25, 25-30, 30-35, 35-40,40- 45, 45-
50, 50-55, 55-
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
60, 60-65, 65-70, 70-75, 75-80, 80-85, 85-90. 90-95, 95-100, 100-200, 200-300,
300-400,
400-500, 500-1000, 1000-1500, 1500-2000, or even more than 2000, 2 cm spheres
would
fit within the polymer foam article without overlapping, and without
protruding from the
surface of the article.
1002051 In some embodiments where the polymer foam articles have a shape and a
volume wherein a (theoretical) sphere having a diameter of 2 cm would fit
within the
polymer foam article in at least one location without protruding from the
surface of the
article, the polymer foam article further includes one or more locations
wherein a
(theoretical) sphere having a diameter of 2 cm would not fit, such that the
theoretical
sphere placed in such a location would protrude from the surface of the
article. Such
articles are shown in FIGS. 2-2, 32, and 33. FIG. 2-2 shows a polymer foam
article made
in accord with Example 1: a molded 6 inch (15.2 cm) diameter sphere having a
cylindrical feature attached, wherein the diameter of the cylindrical feature
varies
between 6.25 mm and 10.40 mm, depending on where the cylinder is measured. The
cylindrical feature integrally connected with the sphere in FIG. 2-2 has a
diameter smaller
than 2 cm, and accordingly would not accommodate a 2 cm diameter theoretical
sphere
therein, without the sphere protruding from the cylinder surface. Likewise
FIGS. 32 and
33 show a polymer foam article made in accord with Example 12: a molded 9 inch
(22.9
cm) diameter sphere having a cylindrical feature attached, wherein the
diameter of the
cylindrical feature varies between 5.64 mm and 8.99 mm, depending on where the
cylinder is measured. The cylindrical features integrally connected to the
spheres in
FIGS 32 and 33 have a diameter smaller than 2 cm, and accordingly would not
accommodate a theoretical 2 cm diameter sphere without the sphere protruding
from the
cylinder surface.
1002061 In particular, we have found that obtaining a rapid depressurization
rate, that
is, depressurization rate of at least 0.01 GPa/s to 5 GPa/s, further in
conjunction with the
methods described herein for forming a molten polymer foam, provide the
unexpected
advantage of enabling very large volume polymer foam articles to be formed,
that is,
polymer foam articles having a shape and volume sufficient to accommodate a
theoretical
20 cm --- 1000 cm diameter sphere in at least one location in the interior
thereof, without
protruding from the surface. In some such embodiments, rapid depressurization
is
coupled with a high backpressure required to initiate the depressurization,
such as a
backpressure of greater than 500 kPa, such as a backpressure of 500 kPa to 500
MPa or
56
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
even higher, to obtain a very large volume polymer foam. article. The polymer
foam
articles having a shape and volume sufficient to accommodate a theoretical 20
cm ¨ 1000
cm diameter sphere in at least one location in the interior thereof are
further characterized
as having a continuous thermoplastic polymer matrix defining a plurality of
pneumatoceles throughout the entirety of the article. In some such
embodiments, a
surface region extending 500 microns from the surface of the article comprises
compressed pneumatoceles throughout the entirety thereof.
1002071 An exemplary but non-limiting very large polymer foam article is
demonstrated in Example 22 and shown in FIG. 73, wherein a solid rectangular
cuboid
polymer foam article having a volume of about 17,000 cm3 is formed, further
wherein the
article would fit two theoretical 20 cm diameter spheres in the interior
thereof without
either of the spheres protruding from the surface of the article.
1002081 The manufacture of large, thick, or large and thick polymer foam
articles is
problematic in the industry due to the cooling gradient of the molten foam
after it is
dispensed into a cavity having such dimensions. The interior of such articles
tends to
cool very slowly, and some of the thermoplastic polymer disposed in the mold
cavity
may remain above a melt temperature thereof, allowing significant coalescence
of
pneumatoceles to occur before the thermoplastic solidifies (reaches a
temperature below
a melt transition thereof). In sharp contrast, we have found that large
articles, thick
articles, and large, thick articles are suitably formed using the methods,
materials, and
apparatuses disclosed herein, further wherein the formed polymer foam article
is
characterized by a continuous polymer matrix having pneumatoceles distributed
throughout the article. The slower-cooling interior of larger articles show
minimal or no
evidence of pneumatocele coalescence during cooling. The pneumatoceles remain
intact
or substantially intact during cooling of the molten polymer foam and do not
coalesce
during cooling, resulting in a continuous polymer matrix regardless of size,
thickness, or
volume of the polymer foam article formed.
1002091 This feature of the polymer foam articles described herein is
surprising and
unexpected: the methods of the prior art result in. foams that tend to undergo
pneumatocele coalescence during cooling. Accordingly, a molten polymer foam of
the
conventional art; situated in the interior volume of a mold, may cool so
slowly that
pneumatoceles are able to completely coalesce, and consequently the interior
of a large or
thick article formed using conventional polymer foaming methods may obtain
very large
57
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
Raps or even a completely collapsed structure in the interior thereof. In
sharp contrast,
the molten polymer foams formed according to the present methods do not
undergo
substantial pneumatocele coalescence or collapse of the continuous polymer
matrix
during cooling of molten polymer foam. Accordingly, large and thick polymer
foam
articles with a continuous polymer matrix throughout are achieved using the
methods,
materials, and apparatuses described herein.
1002101 The continuous polymer matrix, as a structural feature of the polymer
foamed
articles in accord with the foregoing methods, apparatuses, and materials is
characterized
as present throughout the entirety of the polymer foamed article, including
the surface
region thereof The surface region may be suitably characterized as the
interior area of a
polymer foam article that is 500 microns or less from the surface. The surface
region as
defined herein is a portion of the area of a foamed article conventionally
referred to the
"skin layer", which is a region free or pneumatoceles or substantially free of
pneumatoceles in polymer foam articles made using conventional methods.
Conventionally formed foam articles include a skin, layer that is at least as
thick as the
surface region, that is, 500 microns thick; but often the skin layer is much
thicker and
may proceed as far as 1 mm, 1.5 mm, 2 mm, 2.5 mm, even 3 mm from the surface
of the
article. However, the polymer foam articles formed using the presently
disclosed
methods obtain a true foam structure from the surface thereof and throughout
the entire
thickness and volume thereof. In embodiments, microscopic inspection reveals
evidence
of pneurnatoceles on the surface of the polymer foam articles formed using the
conditions, processes, and materials disclosed herein Accordingly, the methods
disclosed
herein obtain unexpected results in terms of the continuous nature of the
polymer matrix
structure throughout the entirety of the polymer foam article, in any
direction, and in
every region thereof including within the interior of very large and/or thick
polymer foam
articles and also at the surface and in the surface region of the article.
10021.11 The Examples below include analyses of the surface region of multiple
polymer foam articles made using the methods disclosed herein and that exhibit
this
continuous foam structure. Macroscopically, a polymer foam article made using
the
methods disclosed herein may appear to have a skin layer: that is, the surface
region of
the article can appear to be different from the interior region of the
article. However, we
have found that in sharp contrast to a skin layer characterized by the absence
of
pneumatoceles, the surface regions of polymer foam articles made by the
present
58
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
methods include a plurality of compressed pneumatoceles. Macroscopically the
compressed pneumatoceles create an appearance suggesting a skin layer;
however,
microscopic inspection reveals that the visually apparent difference arises
from a
"flattened" or compressed disposition of the continuous polymer matrix near
the surface
of the article.
100212j Thus, for example as seen in FIGS. 17 and FIG. 18, there is a gradual
transition from spherical to compressed pneumatoceles moving towards the
surface of
polymer foam article formed by employing the conditions, processes, and
materials
disclosed herein. Thus, in embodiments, a surface region of a polymer foamed
article
made using the methods disclosed herein includes a plurality of compressed
pneumatoceles. In embodiments, the compressed pneumatoceles are present in the
surface region of a polymer foam article made using the methods disclosed
herein. In
some such embodiments, compressed pneumatoceles are present within an interior
area
of a polymer foam article that is 500 microns or less from the surface. In
some such
embodiments, compressed pneumatoceles are present within an interior area of a
polymer
foam article that is as far as 2 cm from the surface. Compressed pneumatoceles
are
defined as pneumatoceles having a circularity of less than 1, wherein a
circularity value
of zero represents a completely non-spherical pneumatocele, and a value of 1
represents a
perfectly spherical pneumatocele. In embodiments, pneumatoceles having
circularity of
less than 0.9 are observed in the surface region of foamed polymer articles,
further
wherein 10% to 90%, or 10% to 80%, or 10% to 70%, or 10% to 60%, or 10% to
50%, or
10% to 40%, or 10% to 30%, or 10% to 20%, or 20% to 80%, or 20% to 70%, or 20%
to
60%, or 20% to 50%, or 20% to 40%, or 20% to 30%, or 30% to 70%, or 30% to
60%, or
30% to 50%, or 30% to 40% of the pneumatoceles in the surface region have a
circularity
of 0.9 or less. In embodiments, an average circularity in the surface region
of the foamed
polymer articles is 0.70 to 0.95, such as 0.75 to 0.95, or 0.80 to 0.95, or
0.85 to 0.95, or
0.90 to 0.95, or 0.70 to 0.90, or 0.70 to 0.85, or 0.70 to 0.80, or 0.70 to
0.75, or 0.70 to
0.75, or 0.75 to 0.80, or 0.80 to 0.85, or 0.85 to 0.90, or 0.90 to 0.95.
1002131 In embodiments, compressed pneumatoceles are present in a polymer foam
article more than 500 microns from the surface thereof. For example, in
embodiments,
compressed pneumatoceles are present up ID 1 mm from the surface of a polymer
foam
article, or up to 2 mm, 3 mm, 4 mm, 5 mm, 6 nun, 7 nun, 8 nun, 1 cm, or more
from the
surface thereof. In some embodiments the region of compressed pneumatoceles in
the
59
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
polymer foam article corresponds to 0.01% to 70% of the total volume of the
article, for
example 0.1% to 70%, or 0.5% to 70%, or 1% to 70%, or 2% to 70%, or 3% to 70%,
or
4% to 70%, or 5% to 70%, or 6% to 70%, or 7% to 70%, or 8% to 70%, or 9% to
70%, or
10% to 70%, or 15% to 70%, or 20% to 70%, or 30% to 70%, or 40% to 70%, or 50%
to
70%, or 60% to 70%, or 0.01% to 60%, or 0.01% to 60%, or 0.01% to 50%, or
0.01% to
40%, or 0.01% to 30%, or 0.01% to 20%, or 0.01% in 10%, or 0.01% to 9%, or
0.01% to
8%, or 0.01% to 7%, or 0.01% to 6%, or 0.01% to 5%, or 0.01% to 4%, or 0.01%
to 3%õ
or 0.01% to 2%, or 0.01% to 1%, or 0.01% to 0.1% of the total volume of the
article.
1002141 FIGS. 12 and 14 shows a plot of average pneumatocelc size and average
pneumatocele count versus average pneumatocele circularity for two polymer
foam
articles made using the presently disclosed methods. Quantitative analysis of
pneumatocele size and distribution reveals an inverse relationship between the
average
pneumatocele size and pneumatocele circularity, and an inverse relationship
between the
average pneumatocele size and the number of pneumatoceles.
1002151 FIG. 18 additionally shows visual evidence that pneumatoceles are
present to
the surface of the polymer foam articles formed using the methods, materials,
and
apparatuses as described herein. FIG. 18 additionally shows visual evidence
that a
plurality of compressed pneumatoceles are present substantially 500 microns
from the
surface of the polymer foam articles formed using the methods, materials, and
apparatuses as described herein. In this sense, the polymer foam articles
presently
disclosed obtain a significant difference from foam articles of the prior art.
While the
"skin layer", or first 500 microns of thickness of a foam article made by
conventional
processes include no pneumatoceles or substantially no pneurnatoceles, it is a
feature of
the prior art foam articles generally that the pneumatoceles are spherical
wherever they
are located. Thus, at the thickness in a conventional foam article where
pnetunatoceles
are observed, they are generally spherical, having circularity near or about
1.
Compressed pneumatoceles are not formed using conventional methodology to make
foamed articles, and therefore no distribution of pneurnatocele circularity is
observed in
such conventional foam articles. Further, pneumatoceles are not even formed in
the first
500 microns thickness of a foam article made by conventional processes, so no
comparisons regarding pneumatoceles can be drawn as to the surface region of
the
foamed polymer articles as described herein and the foamed articles made using
conventional injection molding methods.
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1002161 Further, conditions, processes, and materials disclosed herein are
suitably
optimized to form polymer foam articles having different physical properties
depending
on the targeted end use or application. For example, the density of a polymer
foam
article is suitably varied as a function of expansion volume. By lowering the
expansion
volume, the density of the resulting polymer foam article is decreased in a
generally
linear fashion, for example as shown in FIG. 5. Also as can be seen from FIG.
5,
increasing the expansion period of time causes a denser polymer foam article
to form.
Such conditions and other variables, all within the scope of the conditions,
methods, and
materials disclosed herein are suitably used to vary the physical properties
of the polymer
foam articles that result.
1002171 In one variation of conditions, processes, and materials disclosed
herein, a
molten polymer foam is suitably dispensed by splitting the flow of molten
polymer foam
into 2, 3, 4, or more pathways heading to multiple molds or mold sections to
form
multiple polymer foam articles from a single shot. In another variation of
conditions,
processes, and materials disclosed herein, two shots are used to fill a single
mold,
wherein the first shot is different from the second shot in terms of the
thermoplastic
polymer content or ratio of mixed polymers, the pneurnatogen source, the one
or more
additional materials optionally included, density, void fraction, depth of the
region of
compressed pneumatoceles, or some other material or physical property
difference.
1002181 In another variation of conditions, processes, and materials disclosed
herein, a
polymer foam article made using the methods disclosed herein was subjected to
fastener
pull out testing according to ASTM D6117. The polymer foam articles obtain
superior
pull out strength over foam articles made using conventional foaming methods.
Further,
the polymer foam articles formed using the materials, methods, and apparatuses
disclosed
herein require no pre-drilling, tapping or engineering of the fastener
location.
10021.91 In yet another variation of conditions, processes, and materials
disclosed
herein, a polymer foam article made using the methods disclosed herein was
subjected to
ballistic testing. Using the guidance of National Institute of Justice (NH)
"Ballistic
Resistance of Body Armor NIJ Standard-0101.06", a series of 3 inch thick
polymer foam
articles were formed from poly ether-amide block copolymers (PEBAX*), linear
low
density polyethylene (LLDPE), and polypropylene using a citric acid based
pneutnatogen
source. Polymer foam articles made using all three of these thermoplastic
polymers were
61
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
found to stop .22 LR handgun bullets, passing NIJ Level I; and were found to
stop 9mm
LUGER handgun bullet, passing NU Levels II and IIA.
1002201 EXPERIMENTAL SECTION
1002211 The following examples are intended to further illustrate this
invention and
are not intended to limit the scope of the invention in any manner. Examples I
and 11
were conducted on an Engel Duo 550 Ton injection molding machine (available
from
Engel Machinery Inc. of York, PA, USA.). Examples 2-4 were conducted on a Van
Dom
300 injection molding machine (available from Van Dom Dernag of Strongsville,
Ohio,
USA). Unless otherwise indicated, the remaining examples were conducted on an
Engel
Victory 340 Ton injection molding machine (available from Engel Machinery Inc.
of
York, PA, USA).
1002221 In the Examples herein, "cc" means "cubic centimeter" or "cubic
centimeters"
(cm3), "sec" means "second" or "seconds".
Standard foam molding and MFIM
1002231 In the Examples herein, two direct injection expanded foam molding
techniques were employed termed herein "standard foam molding" and "molten
foam
injection-molding" ("MFIM").
1002241 In standard foam molding, the following general procedure was used: A)
A
mixture was prepared by blending a polymer (which may be in the form of
pellets,
powder, beads, granules and the like) with a foaming agent (blowing agent) and
any other
additives such as a filler. The mixture was introduced to the injection unit,
and the
rotating injection unit screw moved the mixture forward in the injection unit
barrel, thus
forming a heated fluid material in accordance with normal injection molding
processes.
B) A set volume of the material was dosed to the front of the barrel of the
injection unit
by rotation of the screw, thus moving the set volume from the feed zone to the
front of
the screw. During this feed step, the screw was rotated to translate the
melted mixture
forward into the space in the barrel between the screw and the nozzle,,
thereby providing
the set volume. C) The melted mixture was injected into the mold cavity by
forward
translation of the screw and/or rotation of the screw.
1002251 In the molten foam injection-molding (MFIM) process, the following
general
procedure was used: A) A mixture was prepared by blending a polymer (which may
be
in the form of nurdles, pellets, powder, beads, granules and the like) with a
chemical
62
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
foaming agent, and any other additives such as a filler. The mixture was
introduced to
the injection unit, and the rotating injection unit screw moved the material
forward in the
injection unit barrel, thus forming a heated fluid material in accordance with
normal
injection molding processes. B) A set volume of the material was dosed to the
front of
the barrel of the injection unit by rotation of the screw, thus moving the set
volume from
the feed zone to the front of the screw. During this feed step, the screw was
rotated to
move the material between the screw and the nozzle, thereby providing the set
volume.
C) Once the material had been moved to the front of the screw, in a step
termed herein
"decompression", the screw was moved backwards away from the nozzle without or
substantially without rotation so as to avoid moving more of the material to
the front of
the screw. Unless otherwise noted, the decompression rate, that is, the rate
of
depressurization, is 0.006 GPa or less.
1002261 A space free of the mixture between the screw and the nozzle was
created
within the barrel, the intentional space having a volume termed herein
"decompression
volume". D) The material sat in the bairel between the screw and the nozzle
for a period
of time, termed herein the "decompression time". During the decompression
time, the
material foamed due to a pressure drop created by the space added in step (C).
E) The
molten foam was injected into the mold cavity by forward translation of the
screw and/or
rotation of the screw.
Example I
1002271 Two parts were foam molded using a blend of low-density polyethylene
blended with 2% by weight Hydrocerol Bin 70 foaming agent available from
Clariant
AG of Mutteriz, Switzerland. Molding was conducted using an Engel Duo 550 Ton
injection molding machine (available from Engel Machinery Inc. of York, PA,
USA).
The mold cavity was (approximately) spherical in shape of diameter six inches
(15.24
cm). A first part was molded using a standard foam molding process, and a
second part
was molded using an MFIM process. An aluminum mold having a cold sprue and
runner
system feeding a 6-inch diameter sphere cavity was employed for both parts.
The melt
delivery system for each part was the same, as were most of the processing
conditions.
The process settings for the MFIM process and standard foam molding processes
used as
a control are detailed in TABLE 3. From each process, parts were made of
approximately equivalent mass.
63
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 3: Settings for Example 1; Equivalent mass study
Standard Foam
Molding Process MFIM
Barrel temperatures ( C) 182 / 182 / 182 / 174 / 163 / 154 /161
/ 121 /49
Mold temperature (*C) 10
Injection speed (cc/s) 655.5
Back pressure (kPa) 17237
Decompression (cc)
1 164
Screw speed (cm/sec) 15.24
Cooling time (sec) 160
Hold time (sec) 30
Hold pressure (kPa) 8961
Shot weight (g) 328.9 331.9
1002281 The first and second parts were photographed. FIG. 2-1 is a
photographic
image of the first part, molded using the standard foam molding process. As
seen in the
image, the standard foam process did not yield a part that filled the mold
cavity, and the
part did not match the shape of the spherical cavity of the mold.
1002291 FIG. 2-2 is a photographic image of the second part, molded using the
MFIM
process. As seen in the image, the MFIM process yielded a part that entirely
or
substantially filled the spherical mold cavity and the part matched or
substantially
matched the shape of the spherical cavity of the mold.
1002301 The first part molded using the standard foam molding process was cut
into
two pieces. FIGs 2-3 and 2-5 are photographic images of one of the pieces of
the part
made according to the standard foam molding process. As seen in the images,
the first
part contained a large hollow cavity.
1002311 The second part molded according to the MFIM process was cut into two
pieces. FIGs 2-4 and 2-6 are photographic images of one of the pieces of the
second part.
As seen in the images, the second part lacked the large hollow cavity of the
standard
foam process part. The MFIM part had a cell structure throughout.
64
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
Example 2
1002321 Two parts were formed by foam injection molding, a Part A in
accordance
with a standard foam molding process, and a Part B in accordance with an MFIM
process. In both processes, LDPE/talc pellets were dry-blended with foaming
agent and
mixed during loading into the molding machine.
1002331 For Part B, a mixture of low-density polyethylene (LDPE), talc, and
Hydrocerol BIH 70 was formed and fed into a Van Dom 300 injection molding
machine to provide a polymer shot inside the barrel. After the shot
accumulated in the
front of the screw, the screw was translated backwards away from the injection
nozzle
without rotation in accordance with the MF1M method to create a space between
the
screw and the nozzle, the space having a decompression volume. Then, the
mixture
foamed into the space prior to injection into the mold.
1002341 The same procedure was used for Part A except that after the shot
accumulated in front of the screw, the screw was not backed away from the
nozzle, i.e.
decompression volume was zero. The shot was metered to fill the mold cavity
under
standard foam molding conditions with a target of 10% weight reduction
relative to solid
part.
1002351 TABLES 4-7 below show the polymer, mold, machine, and
processing
settings used in Example 2.
TABLE 4: Material Corn position
Weight %
Polymer: LDPE 82 %
Filler: Talc 15 %
Foaming agent: Hvdrocerolg BIN 70 3 %
TABLE 5: Baseline Mold Parameters
Block Mold (2x4x4 inch)
A.STM Mold
(5.08x 10.16x 10.16 cm)
Mold cavity volume (cc) 524.39
Sprue Volume (cc) 17.39
Total Volume (cc) 541.78
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 6: Common Settings for Producing "Zero
Decompression" and MFIM Parts
Barrel Temperatures ( C) 154118511771166
Mold Temperature ( C) 20
Back pressure (kPa) 0
Screw Speed (rpm.) 165
Screw Rotate Delay time (sec) 100
Hold time (sec) 10
Injection Velocity (cc/sec) 394
TABLE 7: Independent Settings
Shot Details Part A Part B
___________________________________________________________________ 1
Polymer mass (g) 456.2 189.4
Polymer volume in barrel (cc) 486.3 162.12
Decompression volume (cc) 0 231.57
Total molten shot size (cc) 486.297 393.69
Cooling time (sec) 800 160
1002361 Each of Parts A and B was cut in half to reveal a cross section. FIG.
3A and
FIG. 3B show the resulting cross sections of Part A and Part B respectively.
As shown in
FIG. 3A, Part A had a thick outer region extending nearly 0.8 inches (20.3 mm)
from the
surface, indicating that more than 50% of the molded part was completely
solid. The
density of Part A was 0.84 Wm.
1002371 FIG. 3B shows a cross section of Part B molded according to the MFIM
process using the settings shown in TABLE 4 and TABLE 5. As seen in FIG. 38,
Part B
had a foam structure that includes a distribution of cell sizes and shapes. A
solid,
unfoaraed outer region is nearly absent from Part B. The density of Patt B was
0.35 g/cc.
1002381 A sphere cavity mold was used to form a further two parts, Part C and
Part D,
by foam injection molding. The same mixture composition of LDPE, talc,
Hydrocerol
BIH 70 was used to form Parts C and D. Part C was made by the MFIM process,
Part D
by the standard foam molding process. Both processes produced a spherical or
approximately spherical part having a six inch (15.24 cm) diameter. Parts C
and D were
cut through the middle (widest part) into two pieces to expose a cross section
of the part.
66
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
FIG. 4A is a photographic image of a cross section of Part C made by the MFIM
process
(471 g, required cooling time 160 seconds). FIG. 4B is a photographic image of
the cross
section of Part D molded using standard foaming process targets (1360 g,
required
cooling time 800 seconds).
1002391 Similar results were obtained as with the block mold. Part C made
according
to the MFIM process showed cells throughout the part, whereas Part D made
according to
the standard foam molding process showed a region adjacent to the outer
surface of the
part that was free or substantially free of cells ("solid"). Part C was less
dense than Part
D.
Example 3
1002401 In Example 3, block parts were molded using the MFIM process at
various
decompression volumes (Trial A) and various decompression volumes and
decompression times (Trial B).
1002411 TABLES 8-10 show the material composition, mold geometry information,
and processing settings used for Trials A and B.
TABLE 8: Material Composition
Weight %
Polymer: LDI'E 82 %
Filler: ¨Talc 15 X)
Foaming agent: Hydrocerol B1H 70 3 %
TABLE 9: Baseline Mold Parameters
Block Mold (2x2x2 inch)
ASTM Mold
(5.08 x 5.08 x 5.08 cm)
Mold Cavity Volume (cc) 132.74
Spree Volume (cc) 17.39
-
Total Volume (cc) 150.13
1002421 Composite LDPE/talc pellets were mixed with foaming agent just prior
to
molding.
1002431 Trial A.
67
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1002441 In Trial A, all variables were held constant except the volume ratio
of polymer
to decompression volume (empty space) in the barrel prior to injection. The
settings for
each sample run of Trial A are shown in TABLE 10:
TABLE 10: Settings for Trial A
Sample Sample Sample Sample Sample --
1 2 3 4 5
Barrel 1711185 17111851 17111851
17111851 17111851
Temperatures CC) 1771166 1771166 1771166
1771166 1771166
=
Mold
21 /1 21 21 21
Temperature ( C)
injection
4137 4137 413 7 4137 4137
Pressure (kPa)
Back pressure (kPa) 0 0 0 0
Decompression volume (cc) 0 7.7 15.4 23.2
30.1
Screw Speed (rpm) 165 165 165 165
165
Overall
76.5 76.5 76.5 76.5 76.5
cycle time (sec)
Shot Size (cc) 92.62 84.91 77.19 69.47
61.75
Decompression time (sec) 20 20 20 20 20
1002451 The volume of molten foam injected into the polymer cavity was
constant, but
the density of the molten foam was a function of the polymer
shot/decompression volume
ratio. The polymer shot/decompression volumes were varied giving parts with
weight
and density as shown in TABLE 11:
68
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE ii: Trial A Part Weights and Densities
Polymer Shot
Total
as a Percentage
Polymer Molten
Decompression of Total Decompr- Part
Part
Volume Foam
Sample Volume in Volume ession time
Weight Density
in Barrel Shot
Barrel (cc) (Polymer + (sec)
(g/cc)
(cc) Volume
Decompression
(cc)
Volume)
1 92 0 92 100% 20 94.1
0.71
2 85 7 92 92% 20 90.4
0.68
3 77 15 92 ¨ 83%
20 86.0 0.65
4 69 23 92 75% 20 81.8
0.62
62 30 92 67% 20 76.1 0.58
1002461 The results in TABLE 11 indicate that by decreasing the mass and
volume of
polymer in the molten foam shot with a commensurate increases in decompression
voltune, the density of the resultant part can be varied.
1002471 Trial B
1002481 In Trial B, five moldings under the same conditions as Trial A were
conducted
three times; once with a decompression time 20 seconds (same as Trial A), once
with a
decompression time of 70 seconds, and once a decompression time of 120
seconds. The
resultant foam-molded parts were weighed and th.e density calculated using the
volume of the mold cavity. The part density was plotted as a function of
decompression
volume for each of the three decompression times. The plots are shown in FIG.
5. As
seen in FIG. 5, part density varied as a function of decompression volume.
Further, as
shown in FIG. 5, the greater the decompression time, the denser the part.
Example 4
1002491 In Example 4, two series of trials were run using the MFIM process,
Series I
and Series II. In Series 1, a constant injection speed was used but mold close
height was
varied. In Series 11, mold close height was increased with increasing
injection speed. In
Series 11, all conditions were kept constant except injection speed (cc/sec)
and mold close
69
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
height. In the trials, LDPE/talc pellets were dry blended with the foaming
agent and
mixed during loading into the molding machine.
1002501 TABLES 12-13 below show the material composition of the injected blend
and the base mold configuration used for the trials.
TABLE 12: Material Composition
Weight %
Polymer: LDPE 82 %
Filler: Talc 15 %
Foaming agent: Hydrocerol BIH 70 3 %
TABLE 1.3: Baseline Mold Parameters
Block Mold (2x4x4 inch)
A.STM Mold
(5.08x 10.16x 1Ø16 cm)
Mold cavity volume (cc) 524.39
Sprue Volume (cc) 17.39
Total Volume (cc) 541.78
1002511 Series I
1002521 In Series', an injection velocity of 394 cubic centimeters per second
was
used, and three trials were run, Trial A with a mold close height of 1.02 mm.
producing
Part A; Trial B with a mold close height of 0.76 mm producing Part B, and
Trial C with a
mold close height of 0.51 mm producing Part C. The settings for the Series I
trials are
shown in TABLE 14:
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 14: Settings
Barrel Temperatures ( C) 154118511771166
Mold Temperature ( C) 20
injection Speed (cc/sec) 394
Back pressure (kPa) 0
Screw Speed (rpm) 165
Screw Rotate Delay Time (sec) 100
Hold Pressure (kPa) 0
Hold Time (sec) 10
Fill Time (sec) 1.78
Mold Close Height (nun) 1.02, 0.76, 0.51
1002531 During each molding cycle (each of Trial A, Trial B, and Trial C), a
strain
gauge (Kistler Surface Strain Sensor Type 9232A. available from Kistler
Holding AG.
Winterthur. Switzerland) was mounted just above or inside the molding cavity.
The
strain sensor contained two piezoelectric sensors that measured the strain of
the
aluminum cavity as a function of time during the molding cycle. The strain
measurement
was used as an indirect measure of the force acting on the surface of the mold
cavity
resulting from the injection of molten foam and any subsequent additional
foaming that
occurred within the mold cavity. The cavity strain measurements are shown in
FIG. 6 for
Trial A, 1.02 mm gap height (line A); Trial B. 0.76 mm mold close height (line
B): and
Trial C, 0.51 mm mold close height (line C). In FIG. 6 the strain (unit
extension per unit
length) is plotted versus time in seconds. The strain curves indicate that the
pressure was
higher in Trial C than in Trial B and Trial B was higher than in Trial A.
1002541 FIG. 7 includes photographic images showing a side view, a top view,
an
oblique view, and a bottom view of Parts A, B, and C. Parts A and 13 showed
evidence of
collapse, as the parts did not sufficiently match the mold cavity shape. Part
A showed
more collapse than Part B. Part C was more fully formed than either of Parts A
and B in
that the edges of Part C were better defined, and Part C conformed better to
the mold
cavity shape, and the interior of the part appeared more homogenous.
1002551 It was believed that parts could partially collapse in the cavity
during molding
if sufficient pressure is not supplied to stabilize the foam in the cavity
during
solidification. Accordingly, in Series II the mold was closed more tightly at
slower
71
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
injection rates in order to maintain sufficient pressure to prevent collapse
of the part
during molding.
1002561 Series II
1002571 In Series II the gap between mold halves, the mold close height, was
systematically decreased as the injection rate was decreased. The molding
conditions
used were the same as those in Series I except that the injection rates and
mold close
heights used were those as shown in TABLE 15:
TABLE 15: Series II
Trial Injection Rate (cc/sec) Mold Close Height (mm)
A' 394 +0.51 (gap)
B' 317 0.21 (gap)
C' 162 -0.26 (pressure)
fl 85 -0.51 (pressure)
1002581 Four parts were produced in Trials A', W, C', and D', Parts A', B',
C', and D'
respectively.
1002591 Each of Parts A', B' C' and D' was cut into two, and the cross section
photographed. The photographic images are shown in FIG. 8. In order to produce
a part
that did not collapse before solidification, the mold halves had to be
increasingly closed,
as shown in TABLE 15, until they were actually being pressed together (as
indicated by
negative dimension).
1002601 Parts A', B' C', and D' showed no evidence of collapse, had well
defined
edges and surfaces, and appeared fairly unifonn. Accordingly, parts were made
using the
MFIM process using drastically different injection rates by controlling the
pressure
within the cavity during injection, e.g. by varying mold close height.
Example 5
1002611 In Example 5, the same LDPE composite material as Examples 1-3 was
used
in a non-standard two cavity mold with molding parameters as shown in TABLES
16-18.
72
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 16: Material Composition
Weight %
Polymer: LDPE 82 %
Filler: Talc 15 %
Foaming agent: Hydrocerolg BIH 70 3 %
LDPEfrale pellets dry blended with foaming agent and
mixed during loading into molding machine.
TABLE 17: Baseline Mold Parameters
Total Mold Cavity Volume (cc) 1232
Spnie & Runner Volume (cc) 18
Single Mold Cavity Volume (cc) 607
73
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 1.8: Machine Setpoints and Niold Details
Shot size (cc) 555.7
Decompression volume (cc) 463.1
Decompression time (s) 160
Pack Volume Time (sec) 0.00
Pack Volume Speed (cm/sec) 0.00
Hold Press (kPa) 0.00
Hold Time (sec) 10.00
Back Pressure (kPa) 0.00
Cushion (cm) 0.00
Cooling Time (sec) 180.00
Sprite Break (cm) 2.54 (Stack)
Sprite Volume (cc) 18
Barrel Temperatures ("C) 163118511771166
Mold Temperature ( C) 26.7
Injection Velocity (cc/sec) 394
Screw Speed (rpm) 1 65
Screw Rotate Delay lime (sec) 20
Fill Time (sec) 2.383
1002621 Example 5 produced the parts 51 shown in FIG. 9. During injection the
molten foam melt entered through the sprue 52 and split off into two separate
channels to
fill the parts 51 substantially simultaneously. Accordingly, the MFIM process
could be
used to form parts by splitting the melt into multiple pathways in the mold.
Example 6
1002631 A first part was molded using a formulation of 15 wt.% talc / 85 wt%
polycarbonate composite was blended with 3 wt.% Hydrocerole XH-901 prior to
loading
into the injection molding machine. The first part was formed using the MFIM
process.
Process details are provided in TABLES 19 and 20. The part was made using a
4x2x2
block mold (5.08 x 10.16 x 10.16 cm) with a mold cavity volume of 524.4 cc and
a sprue
volume of 17.4 cc. The sprue was cut from the part, and the part was then
subject to X-
74
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
ray tomography to quantify the cellular structure formed within the 5.08 x
10.16 x 10.16
cm geometry.
TABLE 19: Material Composition
Weight %
Polymer: Polyearbonate 82 %
Filler: Talc 15 "A)
Foaming Agent: Hydrocerol(k. 3 %
901
TABLE 20: Settings
Barrel Temperatures ( C) 28812821277126012321204
Nozzle Temperature ( C) 288
Feed Throat Temperature ( C) 65.5
Mold Temperaturo 32
Injection Speed (ce/s) 655.48
Specific Back Pressure (kPa) 6,895
Polymer Shot Size (cc) 139
Decompression Size (cc) 90
Total Molten Foam Shot Size (cc) 229
Screw Speed (cm/sec) 7.6.2
Screw Rotate Delay Time (sec) 40
Appx. Decompression Time (sec) 80
Hold Pressure (kPa.) 0
Hold Time (sec) 0
Cooling Time (sec) 120
Clamp Force (kN) 267
1002641 X-Ray tomography was carried out using a Zeiss Metrotom 800 130 kV
Imaging system (available from Carl Zeiss AG of Oberkochen, Germany). The
instrument measured the attenuation of the X-ray radiation due to the
component
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
geometry and the density of the material used. The column data were calculated
using
the Feldkamp reconstruction algorithm, a standard technique for the industry.
The
instrument had a flat panel detector of 1536 x 1920 pixels for an ultimate
resolution of
3.5 pm under the conditions of this measurement.
1002651 An isometric image of a full Zeiss 3D Tomography scan of the first
part is
shown in FIG. 10, with the solid polymer fraction shown as transparent, the
cells shaded
for visualization, and the cutting plane A-A for single cross-section
indicated. FIG. 11 is
a single-plane cross section A-A selected from the X-ray data with a threshold
analysis
applied to allow for discrete cell identification and subsequent quantitative
analysis.
1002661 The circularity of the cross-sections of the cells was obtained. The
circularity
of these cross sections was used as a measure of the sphericity of the cells.
Accordingly,
circularity and sphericity are used interchangeably in the Examples.
Quantitative
analysis shown in FIG. 12 revealed a cell distribution of both counts and
average size as a
function of the circularity of each cell. A circularity value of zero
represents a
completely non-spherical cell., and a value of I represents a perfectly
spherical cell. The
data showed a distribution of cell sizes and shapes. With the exception of the
most
deformed cells (indicated by 0.1-0.2 on the circularity scale), there was an
inverse
relationship between the average cell size and the number of cells of a given
circularity.
Further, there is an inverse relationship between the average cell size and
the number of
cells.
1002671 Using an MFIM process, a second, spherical, part of diameter of six
inches
(15.24 cm) was molded from. low-density polyethylene (LDPE) using the polymer
formulation and processing parameters as outlined in TABLE 21 and TABLE 22.
The
LDPE/talc pellets were dry blended with the foaming agent, HydroceroKR) BIH 70
and
mixed during loading into the molding machine.
TABLE 21: Material Composition
Weight %
Polymer: LDPE 82 %
Filler Talc 15%
Foaming Agent: Hydrocerol BIH-70 3%
76
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
FABLE 22: Settings
Barrel Temperatures ( C) 18211741171117111661135
Nozzle Temperature ( C) 182
Feed Throat Temperature ( C) 54
Mold Temperature ( C) 21
Injection Speed (cc/sec) 655.5
Specific Rack Pressure (kPa) 6895
Polymer Shot Size (cc) 574
Decompression Size (cc) 1475
Total Molten Foam Shot Size (cc) 2048
Screw Speed (cm/sec) 15.24
Screw Rotate Delay Time (sec) 60
Appx. Decompression Time (sec) 100
Hold Pressure (kPa) 0
Hold Time (sec)
Cooling Time (sec) 160
Clamp Force (kN) 178
1 _______________________________________________________________________
1002681 FIG. 13 is an x-ray tomographic image of a cross section of the
sphere. As
seen in FIG. 13, the outer region contained a plethora of smaller cell sizes
with larger
cells in the central region.
1002691 FIG. 14 shows a plot of average cell size and average cell count
versus
average cell circularity and reveals an inverse relationship between the
average cell size
and the circularity and an inverse relationship between the average cell size
and the
number of cells.
Example 7
1002701 An MFIM process was used to mold an LDPE composite sphere (92 wt. %
polymer, 5 wt. % talc, and 3 wt. % Hydrocerole BIH 70) with a diameter of
three inches
(7.62 cm) and the resulting foam cell structure detailed in FIGs 15-18.
Molding
conditions are provided in TABLE 23. The part was molded on an Engel Victoiy
340
Ton injection molding press in a custom designed, water cooled aluminum mold.
'Ihe
voltune of the mold cavity was 15.38 in3(252 cc), the shot size was 5 in3 (82
cc), and the
77
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
decompression volume in the barrel was 5 in3 (82 cc). The decompression time
was 77
seconds. The molded part weight was 80.31 g, yielding a final part density of
0.32 glee.
TABLE 23: Machine Setpoints and Mold Details
Pack Volume Time (sec) 0.00
Pack Volume Speed (cm/sec) 0.00
Hold Press (kPa) 0.00
Hold Time (sec) 0.00
Cushion (cm) 0.00
Cooling Time (sec) 120.00
Sprue Break (cm) 2.54 (Stack)
Sprite Volume (cc) 18
Mold Cavity Volume (cc) 252
Barrel Temperatures ( C) 180117411661160
Mold Temperature ( C) 13
Injection Speed (cm/sec) 51
Back Pressure (kPa) 689.5
Screw Speed (cm/sec) 30.5
Screw Rotate Delay Time (sec) 40
Fill Time (sec) 2.38
Clamp Force (kN) 98
1002711 After removal from the mold, the part was aged in ambient
conditions for 24
hours, then scored and submerged in liquid nitrogen for two minutes. After
removal from
the liquid nitrogen, the sphere was fractured along the scored surface line
and the fracture
surface was imaged using an environmental scanning electron microscope (ESEM)
(FEI
Quanta FEG 650). The images shown in FIGs 15-18 are micrographs at various
magnifications taken of the fracture surface of the sphere part using a large
field detector,
5.0 kV and 40 Pa of pressure.
1002721 The white box in FIG. 15 indicates the area detailed in FIG. 16. The
white
box in FIG. 16 indicates the area detailed in FIG. 17.
78
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
[002731 In FIG. 17, the cells to the left of the image are larger and
relatively spherical,
whereas those cells to the right side of the photograph appear progressively
flattened as
they approach the surface of the sphere.
1002741 The image in FIG. 18 details the area indicated by the white box in
FIG. 17.
As seen in FIG. 18, there is a gradual transition from spherical to
"flattened" or
compressed cells moving towards the surface of the part.
Example 8
1002751 To establish the baseline differences between parts of standard
thickness
manufactured under standard foam molding conditions, a recently published
study of
standard foam injection molding (Paultkiewicz etal., Cellular Polymers 39, 3-
30 (2020))
was used to establish a molding parameter baseline using a 16-run statistical
analysis
designed experimental (DOE) approach. Material (standard molding grade
polypropylene with 0 wt%, 10 wt%, and 20 wt.% talc; and 0 wt%, 1 wt%, and 2
wt% of
1-13,7drocerol BIH 70 (foaming agent)) was compounded to specifications
outlined in the
publication in order to closely mimic the baseline study. The study was
designed to
investigate the influence of foaming agent concentration, talc content, and
process
conditions on selected propeities of injection molded foam paits. A standard
ISO tensile
bar mold having cavity dimensions of 4.1 mm in thickness, 10 mm width in the
gauge
length, and 170 mm in length was used. No special venting was developed for
the ISO
bar mold. After ensuring that the injection molding machine, material
formulations, and
process window were able to replicate results published by Paultkiewicz etal.,
a second
study was carried out using process variables specific to MEW, specifically
decompression volume and decompression time, while pressure and holding time
(important variables in the published study) were set to a constant value of
zero kN and
zero seconds respectively.
1002761 The molding was completed using an Engel Victory 340 Ton machine
equipped with water cooling. The constant and variable process conditions that
were
used are shown in TABLE 24 for both the "standard" foam molding process and
the
MFIM molding process.
79
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE: 24: Constant Machine Setpoints and Mold Details
Standard Molding MFIM Moldino
Variable Settings
Designed Experiment Variable Low / Med / High levels
Foaming agent content (ba) (wt
0 / 1 / 2 0 / 1
/ 2
%)
Talc content (ta) (wt %) 0/ 10 / 20 0/ 10 / 20
Injection Velocity (cc/sec) 34.4 / 54.6 / 74.6 34.4 / 54.6 /
74.6
Hold Pressure (kPa) 75840 / 19995 0
Hold time (sec) 2 / 20 0
Decompression Volume (cc) 0 / 7.4 / 14.7
Decompression Time (sec) 15
Constant Settings
Cooling Time (sec) 20
Mold Temp ( C) 20
Injection Temp (T) 210
Specific Backpressure (kPa) 6895
Cooling Time (sec) 20.00
Barrel Temperatures (T) 210 /
210 / 210 / 177 / 163 / 149 / 38
Shot size (in3) 44.2 29.5
___________________________________________________________________________ 1
1002771 The designed study required 16 combinations of processing
conditions/polymer formulation (16 runs) for each of the standard molding and
MFIM
molding studies. Multiple replicates were conducted of each run, producing
replicate
parts for each run. TABLE 25 outlines the variation between runs in both the
standard
and MFTM designed runs. The runs were conducted in a random order to avoid
bias.
The L/T ratio for the ISO tensile bar is 40.5.
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 25
Molten Foam Injection Molding Process Standard Foam Molding
Process
Foaming Talc Hold Foaming Talc
Run Decompression Run
agent loading pressure agent loading
# volume (cc) #
(0/0) (wt%) (liPa) (Vo) (wt%)
I 0 0 0 1 75842 0 0
...._
z. , 14.7 0 0 2 75842 0 0
3 0 0 20 ." 75842 0 20
4 14.7 0 20 4 75842 0 20
7.4 I 0 10 5 75842 0 10
6 7.4 1 ¨1 0 6 19995 1 0
7 7.4 1 20 7 19995 1 20
8 0 1 10 8 19995 1 10
9 14.7 1 10 9 19995 1 10
7.4 1 10 10 19995 1 10
11 7.4 1 10 11 19995 1 10
' 12 ' 0 -, 0 12 19995 2 0
13 14.7 ,
0 13 19995 2 0
14 0 1 70 14 19995 2 20
14.7 2 20 15 19995 2 20
............................. , ....
16 7.4 1 ___ 20 16 19995 2 10
1002781 After molding 32 unique process combinations of the two 16-run DOE
studies, five samples of each series were mechanically tested for tensile
strength and the
fracture surface imaged after fracture. A representative selection of ISO bar
cross
sections from Runs 10, 11, 14, and 15 of the standard foam molding process are
shown in
FIG. 19 and a representative selection of ISO bar cross-sections from Runs 9,
10, 15, and
16 of the MFIM process are shown in FIG. 20.
1002791 Differences between the standard foam molding technique as adopted
from
recent literature and the MF1M process arc apparent when examining the cross-
section
images. The structure in the standard process bars consist of relatively few,
but well
defined, spherical cells flanked ou all sides by a thick region of polymer
lacking cells.
The cross-section images obtained from the standard foam molding process are
in good
81
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
agreement with those in the publication by Paultkiewicz et al. and are
representative of
the current industry standard. In contrast, the typical cross sections of the
MFIM molded
ISO bars display a cell structure with more asymmetric, deformed cells.
1002801 The cells in the MFIM cross-section also proceed to the region
adjacent to the
surface in almost all cases, similar to previous examples described herein,
and despite
being a much thinner part with a much larger L/T ratio (40.5) than previously
described.
The results clearly indicate that the adoption of the decompression step in
MFIM, in
combination with eliminating the standard foam molding process variables of
hold
pressure and time, results in a significantly different cell structure in
molded parts.
1002811 Tensile tests of five replicate parts from MFIM Run 9 were run. FIG.
21
shows a representative cross section and a series of stress/strain plots for
the five parts
tested from MFIM Run 9.
1002821 Tensile tests of five replicate parts from Run 10 made using the
standard foam
molding process were run. FIG. 22 shows a representative cross section and a
series of
stress/strain plots for the five parts tested from standard foam process Run
10.
1002831 The average tensile strength of the five parts from MFIM Run 9 was
less than
that of the average of the five parts from standard foam molding process Run
10.
However, the MFIM parts showed a greater strain (elongation) at break.
1002841 More cells were visible in the cross section of the MFIM part from Run
9 (102
cells) than in the standard foam molding process part from Run 10 (19 cells).
1002851 X-ray tomography scans (completed under conditions described in
Example
5) were completed for a randomly selected replicate part from Run 15 of the
standard
foam molding process (shown in FIG. 23) and for a randomly selected replicate
part
produced during Run 9 of the MFIM process (shown in FIG. 24). Both FIG. 23 and
FIG.
24 show a "top" view, taken at 50% depth and a "side" view, also taken at 50%
depth.
1002861 In the developed cell structure of the standard foam molding process
ISO bar
(FIG. 23), cells were circular in shape and the regions adjacent to the
surface of the bar
lacked cells.
1002871 in contrast, the ISO bar produced via the MFIM process as shown. in
FIG. 24
includes a high population of elongated cells and cells are found in the
region adjacent to
the surface of the part.
82
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
Example 9
1002881 To explore the dependence of final cell structure on MFIM processing
conditions, eight tensile bars of LDPE were molded using the MF1M process on
an Engel
Victory 340 Ton injection molding machine. The mold included an aluminum
material
modified tensile bar cavity having dimensions of 24 cm in length, a thickness
of 2.54 cm,
and a variable width with gauge length of 6 cm and a gauge width of 2.54 cm
tapering to
flanges of 3.5 cm in width. The large tensile bar was fed from a cold sprue
and runner
system through a gate 1.0 cm in diameter. The material formulations consisted
of LDPE
with or without talc, always containing 2 wt % foaming agent Clariantl-
lydroccrolt B111
70. The melt temperature was set to the profile detailed in TABLE 26, and
residence
time in the barrel was 13 minutes before building a shot for injection. After
building the
shot, the screw was retracted to give a decompression volume of either 4.0
cubic inches
(66 cc) or 6.0 cubic inches (98 cc) and the LDPE foaming agent mixture was
allowed to
foam for either 15 or 45 seconds into the empty barrel space prior to
injection. The study
was completed for both unfilled LDPE and 15% talc filled LDPE. Detailed
process
conditions are shown in TABLE 26.
83
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 26: Constant Machine Setpoints and Mold Details for NIFIN1 or
Large Test Bar
Designed Experiment Variable Low / High levels
Talc Content (wt 0 / 15
Decompression Volume (dv) (cc) 66/ 98
Decompression Time (dt) (see) 15 / 45
Constant Settings
Foaming Agent Content (v. t %) 2
Cooling Time (sec) 60
Mold Temp ( C) 10
Injection Temp ( C) 182
Injection Velocity (cc/sec) 328
Specific Back Pressure (kPa) 6895
Cooling Time (sec) 60.0
Barrel Temperatures ( C) 210 / 210 / 210 / 177 / 163 /
149 / 38
Shot Size (cc) 98
Clamp Force (kN) 89
1002891 FIG. 25 shows an X-ray scan of one of the parts from this study,
showing the
overall shape, of each part.
1002901 FIG. 26 depicts a cross section of each test bar molded in the study,
cut from
the middle of the gauge length, with the variable parameters indicated. The
sample set
includes two primary groups: samples made with talc and samples made without
talc. In
FIG. 26, the sample set on the left depicts those parts made without talc.
These parts
display a smaller cell structure in the core of the part, and the integrity of
the developed
cell structure is largely unaffected by the changes in decompression ratio and
decompression time, indicating the decompression ratios and times were all
within an.
acceptable range.
1002911 The sample set on the right depicts those bars containing 15 wt% talc.
Some
smearing on the part surfaces resulted from knife damage on the low-modulus
LDPE and
is not representative of part quality. The cell structure in the talc parts
was consistently
larger, and the circularity of the cells was slightly lower than the talc-free
equivalents.
84
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1002921 An X-ray tomography image was taken of a cross section from the major
surface alxiut 50% into the MFIM part made with 15% talc, 6 in' (98 cc)
decompression
volume, and 15 seconds decompression time. The image is shown in FIG. 27.
Example 10
100293j A tensile bar part was made using a standard foam molding process from
LUPE loaded with 15 wt% talc, and 2 wt% Hydrocerol BIE. 70 using processing
parameters as described for Example 9, but without the decompression step of
the MFIM
process. This standard foam molding part was compared with the MF.1.M. part
made with
15% talc, 6 irr3 (98 cc) decompression volume, and 15 seconds decompression
time from
Example 9. Using methods as described in Example 6, X-ray tomography images
were
taken of a central portion of each of the parts (MFIM molding and standard
foam
molding) at a variety of depths from a major surface. Cross section images
were also
recorded. The images are shown in FIG. 28.
1002941 X-ray tomographic analysis of cell count, cell circularity, and
average cell size
(longest dimension of cell) was performed on the images of each tensile bar
part (MFIM
and standard process materials) at each depth from the major surface. Cell
count, cell
circularity, and average cell size were each plotted against depth of the
cross section; and
the respective plots are shown in FIGs 29-31 respectively.
1002951 As shown in FIG. 29, cell count was higher in the MFIM molded part at
all
depths. As seen throughout the Examples and Figures, the part molded using the
standard foam. molding process appears to have no or substantially no cells in
the region
or "skin" adjacent to the surface, e.g. in about the first 2.5 mm of depth
from the major
surface, whereas cells are present in the part molded using the MFIM process
within the
region between about 2.5 mm below the surface and the surface.
1002961 As shown in FIG. 30, in general cell circularity was greater in the
standard
foam molding process sample than in the MFIM-molded part except towards the
middle
of the TvIFIM part, where circularity was also high in the MFIM molded sample.
1002971 As shown. in FIG. 31, cell size was generally larger for the standard
foam
molded tensile bar part, but fell off rapidly to zero in the regions proximal
the outer
surfaces (e.g. within 2.5 mm of the surface). In contrast, v11 size was more
uniform
through the depth of the MFIM-molded part, and cells continued right to the
surface.
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1002981 The same trends are seen by visual examination of the cross sections
shown in
FIG. 28. Within 2.5 mm of any outer surface, the standard foam molded part
appears to
lack cells, whereas cells are visible up to the outer surface in the MF1M
part.
Example 11
1002991 A large sample of recovered ocean plastic was analyzed using
differential
scanning calorimetry and was estimated to consist of approximately 85 wt% of
HDPE,
with the balance comprising polypropylene and contaminants.
1003001 Two parts were successfully molded from the ocean plastic using an
MF1M
process, a 4"x4"x2" brick and a sphere of 15.24 cm diameter. Molding was
conducted
using an Engel Duo 550 Ton injection molding machine (available from Engel
Machinery Inc. of York, PA, USA). Both parts were center-gated and filled by a
viscous
coil-folding flow.
1003011 Processing parameters and characteristics of the resulting part are
listed in
TABLE 27 and TABLE 28 respectively:
TABLE 27
+I 6" Sphere 4"x4"x2"
Brick
Mat:Alai Ocean Plastic Ocean
Plastic
Machine Engel Duo 550 Ton Engel Duo
550 Ton
Decompression volume (cc) 819
295
Decompression time (sec) 340 60
Foaming agent Bill 70 (wt %) 3 3
Cooling Time (sec) 1 400
120
Mold Temp ( C) 35 38
injection Temp ( C) 204
204
Injection Velocity (cc/sec) 655
787
Specific Back Pressure (kPa) 6895
13790
Barrel Temperatures ( C)
204 / 191 / 177 / 163 / 149 / 107 / 54
Shot size (cc) 1229
279
Clamp Force (kN) 445
445
Hold Time (s) 0
Hold Pressure (kPa)
0
86
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 28
Part Characteristics 6" Sphere Brick
Part Weight (a) 921.6 253.2
Volume (without runner) (cc) 1856 524.3
Part Density (glee) 0.496 0.482
Example 12
1003021 A sphere of nine inches (22.86 cm) in diameter, "Sample
10", was molded
using the MF1M process described herein. Further, a second sphere of nine
inches (22.86
cm) in diameter, Sample 20, was molded using a variant process. The variant
process,
termed herein "reverse MFIM" process was as follows:
1003031 A) A mixture was prepared by blending a polymer (which may be in the
form
of pellets, powder, beads, granules, and the like) with a chemical foaming
agent, and any
other additives such as a filler. The mixture was introduced to the injection
unit, and the
rotating injection unit screw moved the material forward in the injection
molding
machine barrel, thus forming a heated fluid material in accordance with normal
injection
molding processes. B) The screw was moved backwards towards the hopper,
creating an.
intentional space between the screw and the nozzle within the barrel. C) A set
volume of
the material was dosed to the front of the barrel of the injection unit by
rotation of the
screw, thus moving the set 'volume from the feed zone to the front of the
screw and into
the intentional space created in step B. During this feed step, the screw was
rotated to
move melted material to the space in the barrel between the screw and the
nozzle, thereby
providing the set volume. However, the set volume occupied only part of the
intentional
space, thereby providing volume for the shot to foam and expand, the
decompression
volume. D) The material sat in the barrel between the screw and the nozzle for
a period
of time, termed herein the "decompression time". During the decompression
time, the
material expanded due to foaming to fill or partially fill the space created
in step (B). E)
The molten foam was injected into the mold cavity by forward translation of
the screw
and/or rotation of the screw.
1003041 Thus the regular and reverse MF1M processes differed from each other
in that
in the MF1M process, the screw was rotated to introduce the shot to the front
of the barrel
before the screw was translated backwards to allow for a decompression space;
whereas
in the reverse process the screw was translated backwards to allow for a
decompression
87
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
space before the screw was rotated to introduce the shot of material into the
intentionally
created space.
1003051 Sample 10 and Sample 20 were both molded of virgin LDPE containing 2%
Hydrocerolg BIH 70, 2% talc, and 1% yellow colorant. Molding was carried out
on the
Engel Duo 550 Ton injection molding machine (available from Engel Machinery
Inc. of
York, PA, USA). The mold was a spherical cavity within an aluminum mold fed by
a
cold runner and sprue.
1003061 The processing parameters are shown in TABLE 29:
TABLE 29
Sample 10 Sample 20
Process Method MFIM Reverse MFIM
Shot Size (cc) 1639 1762
Decompression Volume (cc) 1475 1475
Batter (cc) 3114 3236
Shot to Decompression Volume
10:9 10:9
Ratio
Cooling Time (sec) 300 300
Screw Rotation Delay Time (sec) 140 140
Metering Performance (cc/sec) 32.8 32.8
Decompression Speed (cc/sec) 164 164
Approximate Decompression Time
101 106
(sec)
Clamp Force (kN) 89 89
Specific Back Pressure (kPa) 6895 6895
Injection Pressure (kPa) 52476 53827
Injection Speed (cc/sec) 655 655
¨ -
Screw Speed (cm/sec) 75.24 15.25
=
Mold Temperature ( C) 10 10
Shot Weight (g) 1334 1335
1903071 The density of the parts, both Sample 10 and Sample 20, was 0.214 Wee
with
a density reduction in both cases of 77%.
88
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1003081 A photograph of Sample 20 is shown in FIG. 32 and of Sample 10 in FIG.
33,
with each spherical part mounted on a stand. As can be seen in the Figures,
Sample 20
made using the "reverse MFIM process" exhibited an uneven surface, whereas the
surface of Sample 10 made using the MFIM process was much more even. Average
wrinkle depth was estimated using optical microscopy and X-ray tomography. The
average wrinkle depth was measured at less than 50 microns for Sample 10, but
565
microns for Sample 20.
1003091 Each of Sample 10 and Sample 20 was cut into half to provide a cross
section
at the maximum diameter. The cross section of the four pieces was
photographed. One
half of Sample 20 made by the reverse MFIM method is shown in shown in FIG. 34
and
one half of Sample 10 is shown in FIG. 35. Close examination of the edge
showed that in
Sample 10 and Sample 20, cells were found right up to the surface, e.g. within
2.5 mm of
the surface, unlike parts produced elsewhere in the Examples by the standard
foam
method.
1003101 X-ray tomography was performed on the first inch of depth. of a sample
of
Sample 10 and of Sample 20, and using methods described for Example 6, cell
count and
cell size was measured for different distances from the surface of each
sample. Plots are
given in FIG. 36 and 37, wherein "MFIM" refers to Sample 10 and "Reverse MFIM"
refers to Sample 20.
100311j Two further sphere parts, Parts 6 and 7, were prepared under the same
conditions and with the same poly,mer/talc/colorantifoaming agent mix as
Sample 10, i.e.
by the MFIM method. Five cuboid parts, each approximately 2 inches by 2 inches
by 1
inch, were cut from each of Parts 6 and 7, and compression modulus (stress
versus strain)
was tested. The average stress versus the average strain (MFIM method) was
plotted and
is shown in FIG. 38.
10031.21 Two fiuther sphere parts, Parts 22 and 24, were prepared under the
same
conditions and with the same polymer/talc/colorant/foaming agent mix as Sample
20.
Five cuboid parts, each approximately 2 inches by 2 inches by 1 inch (about
5.1 cm by
5.1 cm. by 5.1 cm), were cut from each of Parts 22 and 24, and compression
modulus
(stress versus strain) was tested. The average stress versus the average
strain (reverse
MFIM method) was plotted and is also shown in FIG. 38. as seen in FIG. 38, the
compression moduli of the parts made by the MFIM process (average of Parts 6
and 7)
and the parts made by the reverse MFIM process (average of Parts 22 and 24)
are similar.
89
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1003131 Five strips were cut from each of Parts 6 and 7 (MFIM) and 22 and 24
(reverse MFIM). Each strip was approximately 1 inch by 1 inch by 8 inches. The
flexural modulus (stress versus strain) was tested for all of the strips, and
the results
averaged for the ten MFIM-produced strips and the results averaged for the ten
reverse
MFIM strips. The results are plotted in FIG. 39.
Example 13
1003141 Parts were fabricated using MFIM methods as described
herein, of various
shapes and materials as shown in TABLE 30. The parts were cross sectioned. In
all
cases, a region proximal the surfaces included cells of lower size, but moving
away from
a surface, cell size increased. The region of reduced cell size closer to the
surfaces
transitioncd to a larger cell size further from. the surface. While the
transition was
gradual and so there was no a distinct layer of smaller size and a distinct
layer of larger
size, using microscopy the relative areas of the region of smaller or
"compressed" cells
and the region of larger cells was estimated by eye and confirmed by light
microscopy,
and is shown in TABLE 30. While the numbers are only estimates, examination of
the
images showed that the depth of the region and the percent area that was
occupied by
"compressed" cells varied widely, perhaps depending on part shape, material,
and/or run
conditions.
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 30
Sphere diameter Estimated Percent of Estimated Percent of
Material Filler
(inches) Core Compressed
Zone
LDPE 3 in Sphere 91%
9%
LDPE 15% Talc 1 3 in Sphere 80%
20%
Nylon 6 15% Talc r 3 in Sphere 85%
15%
LDPE 15% Talc 6 in Sphere 87%
13%
LDPE - 6 in Sphere 85%
15%
High-Impact
15% Talc 61n Sphere 85%
15%
Polystyrene
Geometry Estimated Percent of Estimated Percent
of
Material Filler
(inches) Core Compressed
Zone
Metallocene
4x4x2 66% 34%
Polyethylene
High-Impact
15% Talc 4x4x2 53% 47%
Polystyrene
ABS 20% Talc I 4x4x2 71% 29%
Estimated Percet) i: Of Estimated Percent of
Material Filler Geometry
Core Compressed
Zone
Large Tensile
LDPE 54% 46%
Bar
Large Tensile
LDPE 15% Talc 73% 27%
Bar
Estimated Percent of Estimated Percent of
Material Filler Geometry
Core Compressed
Zone
Polypropylene 10% Talc ISO Tensile Bar 65% 35%
Example 14
1003151 A first part was molded using a formulation of 98 wt.% metallocene
polyethylene was blended with 2 wt.% Hydrocerole BIH 70 prior to loading into
the
injection molding machine. The first part was formed using the MFIM process.
Process
details are provided in TABLE 31 and TABLE 32. The part was made using a
2"x4"x4"
91
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
block mold (5.08 x 10.16 x 10.16 cm) with a mold cavity volume of 524.4 cc and
a sprue
volume of 17.4 cc. The sprue was cut from the part, and the part was then
subject to
compression load testing to quantify the compressive strength properties of
the cellular
structure formed within the 2"x4"x4" geometry.
TABLE 31.: Material Composition
Weight %
Polymer: Metallocene Polyethylene 98 %
Foaming Agent: Hydrocerol BIH 70 2 %
TABLE 32: Settings
Barrel Temperatures (_ C) 20411931 1881188 i 177
[16611661
Nozzle Temperature ( C) 204
--------------- Feed Throat Temperature ( C) 49
Mold Temperature ( C) 55
Injection Speed (eels) 655.48
Specific Back Pressure (kPa) 10,342
Polymer Shot Size (cc) 245.8 / 327 7 / 409.7
Decompression Size (cc) (for samples 360.5 /
163.9 / 81.9
A/B/C)
Screw Speed (cm/see) 7 62
Screw Rotate Delay Time (sec) 100 7 i() 7 ]()
Appx. Decompression Time (sec)
Hold Pressure (kPa) 0 --
1003161 Compression testing was carried out on an Instron Universal Testing
System
(available from lnstron USA, Norwood, Massachusetts, USA). Each molded foam
block
was placed between the testing platens and stabilized within an environmental
chamber at
30 C for five minutes prior to testing. The instrument was equipped with a
250 kN load
cell. The compression test rate was 5 mm/min.
1003171 Results showed a compressive modulus was 19 MPa for sample A (0.37
glee),
39 MPa for sample B (0.45 g/cc) and 55 MPa for sample C (0.57 glee). As shown
in
FIG. 40, the compressive strength of metallocene polyethylene (mPE) blocks
increases
with increasing density.
92
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
Example 15
1003181 Two sample parts, Part 87 and Part 111, were foam molded using a blend
of
low-density polyethylene with 2.5 wt % Hydrocerol BIH 70 foaming agent
(available
from Clariant AG of Muttenz, Switzerland). Molding was conducted using an
Engel
Victory 160 Ton injection molding machine (available from Engel Machinery Inc.
of
York, PA, USA). The mold included a cylindrical cavity of 6.35 cm diameter and
5.715
cm height, for a total volume of 180.33 cm3. An aluminum mold having a cold
sprue and
runner system feeding the described cylinder shape was employed for both
parts. The
melt delivery system for each part was the same, and the only process set-
point differing
between the two parts was the decompression volume.
1003191 The process settings used to produce each part are detailed in TABLE
33. A
first part (Part 87) was molded using the MFIM process with 10 seconds of
calculated
decompression time and a decompression volume of 65.55 cc. A second part (Part
111)
was molded under the same conditions, but while a period of 10 seconds for
decompression was allowed, as with Part 87, the screw was not translated
backwards to
allow a decompression volume. Accordingly, the decompression volume was 0 cc.
TABLE 33: Settings, Part 87 and Part 111
Part 87 Part 11.1
Barrel Temperatures ( C) 182.2 I 182.2 182.2 1182.2 1 148.91
137.8 1 37.8
Mold Temperature ( C) 10
Injection Speed (cc/s) 327.7
Back Pressure (kPa) 6R95
Decompression Time (see) 10
Decompression Volume (cc) 65.55 0
Decompression Rate (eels) 163.9
Depressurization Rate (GPaisec) 0.0145
Cushion 0.5
Cooling Time (sec) 160
Shot Volume (cc) 53.3
Final Part Weight (g) 48.4 34.5
93
CA 03223226 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1003201 Both Part 87 and Part I ii were photographed. FIG. 42 is a
photographic
image of Part ii 1 molded using no decompression step. As seen in the image,
the
process without the decompression step did not yield a part that filled the
mold cavity,
and the part did not match the shape of the cylindrical cavity of the mold.
1003211 FIG. 43 is a photographic image of Part 87 molded using a
decompression
volume of 69.55 cc. As seen in the image, the molding process using a
decompression
volume of 69.55 cc yielded a part that entirely or substantially filled the
cylindrical mold
cavity, and the part matched or substantially matched the shape of the
cylindrical cavity
of the mold.
100322J During the molding processes used to create Part 87 and Part 111, the
hydraulic ram pressure and barrel volume in front of the screw (i.e. between
then screw
and the nozzle) were displayed in readouts on the injection molding machine.
The
hydraulic ram pressure was recorded as a function of barrel volume as the
injection
progressed.
1003231 The injection pressure (or specific injection pressure) was calculated
by
multiplying the measured hydraulic pressure of the rain by the machine
intensification
ratio, which for the Engle Victory 160 Ton molding machine is 7.222. The
intensification ratio is a geometric factor to calculate the pressure
amplification due to
geometric differences between the hydraulic ram and the tip of the injection
molding
screw at the molten polymer interface. The injection pressure was plotted
against barrel
volume as displayed in FIG. 44 for the molding processes of both Parts 111 and
87.
1003241 Referring to the plot for Part 1 I 1 in FIG. 44, as expected an
immediate
pressure increase was observed as the barrel volume between the nozzle and the
screw
(i.e. in front of the screw) was decreased to less than the shot volume of
about 53 cc by
translation of the screw towards the nozzle. A final injection pressure of
approximately
65 MPa at the nozzle was achieved with approximately 20 cc of molten polymer
mixture
remaining in the barrel.
1003251 Considering Part 87, a shot of 53.3 cc was built and then a
decompression
volume of 65.5 cc was added to the shot for a total possible shot volume of
118.8 cm3.
Referring to the plot for Part 87, as the screw was translated towards the
nozzle, the
pressure initially began to build when the barrel volume in front of the screw
was about
90 cc. Then the pressure climbed slowly until the barrel volume was just above
70 cc,
when the pressure began to climb rapidly, achieving an equilibrium pressure
after the
94
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
barrel volume was reduced below 53 cc. The pressure/volume profile for the
molding
process of Part 87 was very different from that for the molding process of
Part 111. In
particular, the onset of rapid pressure rise (at a barrel volume of about 73
cc) for Part 87
was at a greater volume than that of onset of rapid pressure rise for Part 111
(at about 53
cc). The difference between these "onset volumes" suggests a higher volume of
shot for
Part 87 before injection into the mold due to expansion of the shot by foaming
thereof
into the decompression volume within the barrel. Accordingly, the extra volume
is
labeled "Barrel Foaming" to reflect this possibility.
Exaxnnle 16
1003261 Two spherical foam molded parts, Part 16A and Part 168, were
separately
made, each from a mixture of virgin low density polyethylene (85 parts by
weight) and
talc (15 parts by weight) using the MFIM process. Each of Parts 16A and 168
was cut
through the middle (widest part) into two pieces to expose a cross section of
the part, and
a photograph taken of the cross section.
1003271 A further two parts, Part I6C and 16D, were made from a mixture of
virgin
low density polyethylene (85 parts by weight) and talc (15 parts by weight)
using the
MFIM process. However, Parts 16C and 16D were made using a reduced clamp force
when compared with the process used to make Parts 16A and 168. Each of Parts
16C
and 16D was cut through the middle (widest part) into two pieces to expose a
cross
section of the part, and a photograph taken of the cross section.
1003281 A further part, Part 16E, was made from a mixture of virgin low
density
polyethylene (85 parts by weight) and talc (15 parts by weight) using the MFIM
process.
Part 16E differed from Parts 16A and 16B in using a different decompression
ratio (the
ratio between the shot volume and the decompression volume). Part 16E was cut
through
the middle (widest part) into two pieces to expose a cross section of the
part, and a
photograph taken of the cross section.
1003291 Each of Parts 16A, 16B, 16C, 16D, and 16E was ground by adding it to a
RAPID Granulator Open-Hearted 400-60 (available from RAPID Granulator AB of
Bredaryd, Sweden), which produced a regrind in the form of flakes. The regrind
from
each of Parts 16A, 16B, 16C, 16D, and 16E was then used as feedstock for
injection
molding to make a new spherical foamed part, 16AR, 16BR, 16CR, 16DR, and 16ER
respectively.
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1003301 Each of Parts 16ARõ 1.6BR, 16CR, 16DRõ and 16ER was cut through the
middle (widest part) into two pieces to expose a cross section of the part,
and a
photograph taken of the cross section.
1003311 Screw rotate delay time for all foam molding processes was 40 seconds.
Other process settings used to produce the parts are detailed in TABLE 34.
Virgin refers
to fresh mixture of virgin low density polyethylene (85 parts by weight) and
talc (15 parts
by weight).
TABLE 34: Settings, Parts 16A-16E and 16AR-16ER
Shot Decomp- Cooling Approximate Clamp
Run Feed-
Part volume ression tim.e decompression force
type stock
(cc) volume (cc) (sec) time (sec) (kN)
Virgin 16A. 655 655 100 60
448
Regrind
16AR 655 655 160 120 448
of 16A
Baseline
Virgin 1613 623 655 100 60
448
Regrind
168R 655 655 160 120
448
of 16B
Virgin 16C 623 655 160 120
, 199
Regrind
Reduced 16CR 655 655 160
120 I 199
of 16C
clamp
Virgin 16D 623 655 160 120
199
force __________________
Regrind
16DR 655 655 160 120
100
of 16D
Reduced Virgin 16E 541 737 160 12-6 448
decomp-
Regrind
ression 16ER 574 655 160 120
100
of 16E
ratio
1003321 FIG. 45 is the photograph of a cross section of Part 16A, FIG. 46 of
Part
16AR, FIG. 47 of Part 16B, FIG. 48 of Part 16BR, FIG. 49 of a cross section of
Part 16C,
FIG. 50 of Part 16CR, FIG. 51 of Part 16D, FIG. 52 of Part 16DR, FIG. 53 of
Part 16E,
and FIG. 54 is the photograph of a cross section of Part 16ER. FIGS. 45-54
collectively
96
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
show that each of MFIM-molded Parts 1.6A, 16B, 16C, 16D, and 1.6E was
successfully
recycled into a further MFIM-molded part; Parts 16AR, 16BR., 16CR, 16DR, and
16ER
respectively.
1003331 A variety of further articles was made using the MFIM process from a
variety
of virgin thermoplastic resins including low-density polyethylene (LDPE), high-
density
polyethylene (HDPE), polypropylene (PP), high-impact polystyrene (HIPS),
polyethylene
terephthalate (PET), polybutylene terephthalate (PBT), polyamide (PA),
thermoplastic
polyurethane (TPU), and thermoplastic olefin (TP0). These further polymer foam
articles were all successfully recycled by regrinding as described in this
example and
using the reground material as feedstock in a further MFIM process, further as
demonstrated in FIGS. 45-54. The polymer foam articles made by recycling are
referred
to as formed from recycled material feedstock. This Example shows that
recycled
polymer foam articles are successfully formed from 100% recycled material
feedstock by
using the MFIM process. Further in this Example, all the polymer foam articles
formed
using the MFIM process are recyclable and therefore also constitute potential
recyclable
material feedstocks.
Example 17
1003341 Five parts were foam molded using a blend of low-density polyethylene
blended with 2% by weight Hydrocerole BTH 70 foaming agent. Molding was
conducted using an Engel Duo 340 Ton injection molding machine (available from
Engel
Machinery Inc. of York, PA, USA). The mold cavity was approximately spherical
in
shape with a diameter of six inches (15.24 cm). A first part was molded using
an MFIM
process without decompression, a second part with 0.5 seconds of calculated
decompression time and decompression volume of 164 cc, and a third with 7
seconds of
decompression time, decompression volume of 164 cc. The backpressure was set
to 6895
kPa and the third process employed a depressurization rate of 0.0059 GPaisec.
The
fourth and fifth parts were molded with nearly two orders of magnitude
difference in
depressurization rates employed.
1003351 An aluminum mold having a cold sprue and runner system feeding a 6-
inch
diameter sphere cavity was employed for all five parts. The melt delivery
system for
each part was the same, as were most of the processing conditions. The process
settings
used to produce each part are detailed in TABLE 35.
97
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 35: Varied decompression time
Part 1 Part 2 Part 3 Part 4
Part 5
Decompression Time
0 0.5 7 10 10
(sec)
Barrel Temperatures (V) 182 / 182 / 182 / 174 / 163/ 154 / 161
/ 121 / 49
Mold Temperature ( C) 10
=
Injection Speed (cc/s) 655.5 ¨ 164
164
Back Pressure (kPa) 6895 689.5 ! 6895
Decompression Volume
0 164 16.4
(cc)
Decompression Rate
163.9 262
(cc/s)
Depressurization Rate
0.0059 0.0009 I .0629
(GPa/sec)
Cooling Time (sec) 200
Shot Volume (cc) 508 500
Part Weight (g) 348.0 376.8 378.4 337.3
343.5
1003361 Each of the five parts was photographed. FIG. 55 is a photographic
image of
the part molded using no decompression. As seen in the image, the process
without
decompression did not yield a part that filled the mold cavity, and the part
did not match
the shape of the spherical cavity of the mold.
1003371 FIG. 56 is a photographic image of the second part, molded using a
decompression time of 0.5 seconds after applying a depressurization rate of
0.0059
GPaisec. As seen in the image, the molding process using 0.5 seconds of
decompression
time yielded a part that entirely or substantially filled the spherical mold
cavity and the
part matched or substantially matched the shape of the spherical cavity of the
mold.
100338j FIG. 57 is a photographic image of the third part, molded using a
decompression time of 7 seconds after applying a depressurization rate of
0.0059
GPa/sec. As seen in the image, the molding process using 7 seconds of
decompression
time yielded a part that entirely or substantially filled the spherical mold
cavity and the
part matched or substantially matched the shape of the spherical cavity of the
mold.
98
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1003391 FIG 68 is a photographic image of the fourth part, molded using a
decompression time of 10 seconds after applying a depressurization rate of
0.0009
GPa/sec. As seen in the image, the molding process using a low
depressurization rate of
0.0009 GPa/sec did not yield a part that substantially filled the mold cavity,
though the
part substantially matched the spherical shape of the mold.
100340j FIG 69 is a photographic image of the fifth part, molded using a
depressurization rate of 0.0629 GPa/sec. As seen in the image, the molding
process using
the stated conditions yielded a part that substantially filled the spherical
mold cavity and
the part matched or substantially matched the shape of the spherical cavity of
the mold.
Example 18
1003411 Two parts were foam molded using a blend of low-density polyethylene
blended with 2% by weight Hydrocerole BTH 70 foaming agent (available from
Clariant
AG of Muttenz, Switzerland). Molding was conducted using an Engel Duo 340 Ton
injection molding machine (available from Engel Machinery Inc. of Yorlc, PA,
USA).
The mold cavity was approximately spherical in shape of diameter six inches
(15.24 cm).
A first part was molded using an MFTM process with 100 psi (689 kPa) of back
pressure
and a decompression rate of 1 cubic inch per second (16.4 cc/s). Back pressure
may be
set by the operator. Decompression rate is determined by the speed of lateral
movement
of the screw away from the collection area of the injection molding machine,
which may
be set by the operator. A second part was molded using 1000 psi (6895 kPa) of
back
pressure and a decompression rate of 16 cubic inches per second (292 cc/sec).
An
aluminum mold having a cold sprue and runner system feeding a 6-inch diameter
sphere
cavity was employed for both parts. The melt delivery system for each part was
the
same, as were most of the processing conditions. The process settings used to
produce
each part are detailed in TABLE 36.
99
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
Table 36: Varied decompression rate
Part! Part 2
Decompression Rate (eels) 16.4 292
Barrel Temperatures ( C) 182/182/182/ 174 /163 /154/161/121/49
Mold Temperature ( C) 10 10
Injection Speed (eels) 165
Back Pressure (kPa) 689 6895
Decompression Volume (cc) 16.4
Depressurization rate
0.0001 0.1049
(GPa/sec)
Cooling Time (sec) 200
Shot Volume (cc) 500
Part Weight (tx.) 330.48 334.47
1003421 Each of the two parts was photographed. FIG. 58 is a photographic
image of
Part 1, molded using a back pressure of 689 kPa, and a decompression rate of
16.4 cc/sec.
As seen in the image, this molding process did not yield a part that filled
the mold cavity
substantially, and the part did not match the shape of the spherical cavity of
the mold.
1003431 FIG. 59 is a photographic image of Part 2, molded using a back
pressure of
6895 kPa and a decompression rate of 0.001 GPa/s. As seen in the image, the
molding
process utilizing a rapid decompression rate of 292 cc/sec, coupled with
backpressure of
1000 psi (6895 kPa) yielded a part that entirely or substantially filled the
spherical mold
cavity and the part matched or substantially matched the shape of the
spherical cavity of
the mold.
Example 19
1003441 A mixture of 98.5 parts by weight of post-industrial polypropylene in
the form
of granules and 1.5 parts by weight of foaming agent (Hydrocerol( BIB 70,
available
from Clariant AG of Muttenz, Switzerland) was foam molded using the MFIM
process
with a 2.25 x 3.875 x 8 inch (5.7 x 9.8 x 20.3 cm) mold cavity to produce a
2.25 x 3.875
x 8 inch (5.7 x 9.8 x 20.3 cm) brick. Three separate such foam molding
processes, 19-
1D, 19-3D, and 19-5D, were performed to produce three polymer foam bricks.
100
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
(003451 Processes 19-1D, 19-3D, and 19-5D were performed in the same manner
using many of the same processing conditions, except for the number of
decompression
steps. Further, the cooling time of the shot before decompression was adjusted
to
maintain the same shot residence time in. the barrel in all three runs:
multiple
decompression steps would have led to a longer cycle residence time of the
shot in the
barrel for a larger number of decompression steps. In addition, the shot
volume for each
run was adjusted to produce three bricks of as similar weight to each other as
possible.
1003461 Process 19-ID was an MFIM process with one decompression step, in
which
after the shot was introduced to the front of the barrel (between the nozzle
and the screw)
and left for a cooling adjustment period, the screw was translated backward
(away from
the nozzle) to provide a decompression volume for ten seconds (decompression
time).
Immediately after the decompression step, the screw was translated forwards
(toward the
nozzle) to inject the shot into the mold.
1003471 Process 19-3D was performed in a similar manner, except that the screw
was
translated backward from a pre-translation position to provide the
decompression volume
for ten seconds (decompression time), and then translated forward to the pre-
translation
position; then backward for a second time to again provide the decompression
volume for
ten seconds decompression time, then translated forward to the pre-translation
position;
and then backward for a third time and left for a decompression time of ten
seconds
before injection. Accordingly, run 19-3D had .three decompression steps
instead of the
single decompression step of run 19-1D.
[003481 Process I9-5D was performed in a similar manner as run 19-3D, except
that
five ten-second decompression steps were performed.
1003491 Several runs of each process were carried out to produce brick parts
by each
process type. Parameters for the three process types are shown in TABLE 37:
101
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 37: Varied number of decompression steps
Run 19-1D I 19-3D 19-5D
Barrel Temperatures ('C)
204 / 204 / 204 1193 /182 / 171 /38
Decompression Volume (cc) 163.87
Mold Temperature ( C) 10
Clamp Force (kN) 996
Decompression Time (see) 10
Specific Back Pressure (MPa) 6.89
Depressurization Rate (GPa/see) 0.0059
Injection Speed (cc/s) 163.87
Shot Volume (cc) 537.50 540.77 557.16
Cooling Time (scc) 330 315
300
Cycle time (min:sec) 5:46
1003501 A brick from each process type was cut into two halves of 1 x 4 x 8
inch (2.5
x 10.2 x 20.3 cm), and the 4 inch x 8 inch cross section of each was
photographed. The
photographs arc displayed in FIG. 60. Parts molded with five decompression
steps
showed larger voids near the area where the melt enters the cavity.
1003511 In addition, photographs were taken in side aspect of the surface of
each cross
sectioned brick at a magnification of 12x. The images show the cross-section
face of
each molded brick, and the original outer surface and edge can also be seen.
The
photographs are displayed in FIG. 61. Each brick showed cells within 500
micrometers
of the surface.
1003521 One half of a brick from each process type was subject to compression
testing.
Compression testing using a modified ASTM D1621 standard test was carried out
on an
Instron Universal Testing System (available from Instron USA, Norwood,
Massachusetts,
USA). Each molded foam block was placed between the testing platens and
stabilized
within an. environmental chamber at 30 'C for five minutes prior to testing.
The
instrument was equipped with a 250 kN load cell. The compression test rate was
5
mm/min.
1003531 Plots of compressive strength versus compressive strain for bricks
from each
process type are shown in FIG. 62. Bricks made by all three processes had a
similar
102
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
maximum compressive strength of about 5.2 MPa. It was noted that the brick
tested for
five the 19-5D process has a large void near the gate.
1003541 One half of a brick from each process type was subject to impact
testing using
an Instron Drop Tower (available from. Instron USA, Norwood, Massachusetts,
USA).
Parts from each process type were tested three times along the center of the
part for an
average maximum force and energy reading. Test results for force at peak are
shown in
FIG. 63 and energy at peak are shown in FIG. 64. The maximum force recorded
for all
three process types was similar, and the average was 3228 N. The maximum
energy
recorded for all three process types was also very similar and the average was
6.2 J.
1003551 In general, no significant differences were observed in the
compressive
strength, impact force, and impact energy for parts resulting from a process
including
only one decompression step, only three decompression steps, and only five
decompression steps. Mechanical properties were very similar, and all three
process
types resulted in parts with cells within 500 microns of the surface of the
part.
Example 20
1003561 The objective of the present example was to make parts having a higher
void
fraction than those previously made using the MFIM process. Two parts were
made; a
foam-molded sphere of 8.25 cm diameter made from a SURIXNTM ionomer (available
from the Dow Chemical Company, of Midland, Michigan, USA) incorporating 4% by
weight Hydrocerol 131H 70 foaming agent (available from Clariant AG of
Muttenz,
Switzerland), and a foam.-molded sphere of approximately six-inch diameter
(approximately 15.2 cm) of a blend of 90 parts by weight low-density
polyethylene and
parts by weight of high-density polyethylene incorporating 3% by weight of the
Bill
70 foaming agent.
1003571 Processing variables were adjusted to achieve high void fractions.
Processing
parameters used to mold the SURLYN sphere into a 7.62 cm diameter spherical
cavity by
an .MFIM process are displayed in TABLE 38 and those for the 15.24 cm diameter
polyethylene sphere in TABLE 39. It is noted that the SURLYN sphere solidified
and
was removed from the mold, and further expansion during cooling resulted in a
sphere
larger than the cavity used to mold the sphere.
103
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 38: High void-fraction SURLYNT" sphere
Process Variable Value
Units
Melt Tem pe r atu re 160116011601160 1601149149
Mold Temperature 12.8
C
Shot Volume 98.3
cc
Clamp Force 294
kN
Decompression Time 70 sec
Specific Back Pressure 6.9
fv1Pa
Blowing Agent 4
Injection Speed 327.7
cc/sec
TABLE 39: High void-fraction polyethylene sphere
Process Variable Value
Units
Melt Temperature 1821182118211821182 171138
'C
Mold Temperature 12.8
C
..... _
Shot Volume 409 7
cc
Clamp Force 294
kN
Decompression Time 10 sec
Specific Back Pressure 6.9 rv1Pa
Blowing Agent 3
=
Injection Speed 409.7
cc/sec
1003581 Each part was cut into two halves, and the cross section colored with
a black
marker pen. A photograph was taken of the cross section. Then a 25x magnified
image
was produced of the cross section close to the surface.
104
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
1003591 The photograph and magnified image of the SURLYN sphere are shown in
FIG. 65.
1003601 The photograph and magnified image of the polyethylene sphere are
shown in
FIG. 66.
1003611 The images confirmed a cell structure across the cross section
including
within 500 microns of the surface of the sphere.
1003621 Each sphere was weighed and the void fraction calculated as follows:
The
equation for the density of a foamed part (Pr) is described in Equation 1:
P f = Equation!,
where M is the mass of the foamed part and V is the volume of the foamed part.
1003631 The void fraction equation is described in Equation 2:
Vf
P1 ¨ 1Equation 2,
Ppolymer
where ppoirn, is the density of the material.
1003641 The part density and void fraction data are set forth in TABLE 40:
TABLE 40: Densities and Void Fraction Data
SURLYN Part LDPE/HDPE Part
Part Weight (g) 1 63.6 281.2
Sphere Diameter
8.25 14.34
(cm)
Sphere Volume (cc) 293.65 1544.96
Sphere Density
0.22 0.18
(g/cc)
Polymer density
0.97 0.92
(g/cc)
Void Fraction (%) 77.7 80.3
Example 21
1003651 An objective of the present example was to demonstrate
that an article
could be made by an MFIM process in which the mold was only partially filled.
1003661 Two flowerpots were molded from low-density
polyethylene (comprising
1.5% by weight Hydrocerol B1.1-1 70 foaming agent, available from Clariant AG
of
105
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
Muttenz, Switzerland) using an MFIM process by foam injection into a mold
having a
mold cavity of volume 10860.20 cc. Run SF produced a flowerpot by filling or
substantially filling the mold cavity. A second run, Run PF, was performed
with a lower
shot volume and lower decompression volume in order to only partially fill the
mold
cavity and produce a partially filled part.
100367j The MFIM mold parameters were the same for the two
runs except for the
shot volume and the decompression volume. The parameters (settings) for the
two runs
are displayed in TABLE 41:
Table 41: Partially and Substantially Filling a mold
Run SF PF
Shot Volume (cc) 7046.44 3523.22
Decompression Volume (cc) 819.35 409.68
Decompression Rate (cc/s) 163.87
Barrel Temperatures ( C) 182 / 182 / 174 / 174 / 160 /160
/49
Mold Temperature (CC) 18.3
Specific Back Pressure (M Pa) 6.9
Injection Speed (cc 573.547
Clamp Force (kN) 981
Cooling Time (sec) 500
Transfer Position (cm) 7.62
Resulting Part Volume (cc) 10083.87 1 5204.60
1003681 The volumes of the two flowerpot parts were measured using a 3-
dimensional
scanning arm, a FARO Quantum ScariArm (available from FARO of Lake Mary, FL,
USA). The resulting part volumes are shown in TABLE 41. The two parts are
shown in
FIG. 67 with the part from Run SF on the left and the part from Run. PF on the
right. The
results of this example demonstrate that a partially full mold can generate a
part by the
MFIM process. The volume of the part from the partially filled mold was
approximately
half that of the part made from the substantially filled mold, yet still had
the critical
characteristics of a flowerpot, viz, the part had structural integrity and no
holes.
106
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
Example 22
1003691 60 blocks were made from high-impact polystyrene including 0376% by
weight of Hydrocerol BIH 70 foaming agent (available from Clariant AG of
Muttenz,
Switzerland) using the MFIM process. Each block was cuboid in shape and had
dimensions of approximately 20 cm by 20 cm by 40 cm. The processing parameters
used
to make the blocks are set forth in TABLE 42:
T.A REX 42: Settings
Barrel Temperatures ( C) 1 7 1 / 171 / 149/ 149 / 149
/ 138
Nozzle Temperature ( C)
171
Nozzle 1
Nozzle Temperature ( C)
1 7
Nozzle 2
Feedthroat temperature ( C) 49
Shot Size (cc) 10651.62
Decompression Volume (cc) 819.36
Cooling Time (scc) 600
Screw Rotate Delay Time (sec) 300
Metering Performance (cc/sec) 40.97
Decompression Speed (cc/sec) 163.87
Appx. Decompression Time (sec) 35
Clamp Force (kN) 996.4
Specific Back Pressure (MPa) i 6.89
Injection Pressure (MPa) 129.14
Injection Speed (eels) 983.23
Screw Speed (m/sec) 0.15
Mold Temperature ("C) 12.78
1003701 A hot sprue and runner system fed the mold:
temperatures of the hot sprue
and runner system arc displayed in TABLE 43.
107
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 43: Hot Sprue and Mold Temperatures
Tip 1 ('IC) 216
Tip 2 CC) 216
Tip 3 CC) 216
Tip 4 ( C) 216
Manifold bottom ( C) 193
Manifold Top ( C) 193
Inlet CC) 193
Gate 1 CC) 216
Gate 2 CC) 216
Gate 3 CC) 216
Gate 4 CC) 216
1903711 The average actual block dimensions for the 60 blocks were 20.005
0.114
cm by 19.964 0.659 cm by 40.066 0.061 cm.
1003721 Three of the 60 blocks were taken. Block 45, Block 27, and Block 60.
Each
block was cut into 16 sub-blocks, which were stacked and photographed to show
the
foam structure of the block in cross-section. A photograph of the sub-blocks
from Block
45 is shown in FIG. 70, the sub-blocks from Block 27 in FIG. 71, and the sub-
blocks
from Block 60 in FIG. 72.
1003731 A photograph of a fort built from the MFIM foam blocks is shown in
FIG. 73.
1003741 Cinder blocks with three channels were also made from high-impact
polystyrene.
1003751 Other materials successfully used to make cinder blocks included
polypropylene, polypropylene filled with 20% by weight glass fiber, and
recycled
polypropylene.
1003761 Other materials successfully used to make solid blocks were
polypropylene
filled with 20% by weight of glass fiber and polypropylene filled with 10% by
weight of
glass fiber.
108
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
Example 23
1003771 In the present example, an MF1M process was used to make blocks from
post-
industrial reground polypropylene.
1003781 Post industrial regrind (P.I.R..) in the form of flakes was obtained
from
Engineered Plastics LLC of Erie, PA, USA. The P.1.R. had a melt index of
between 8
and 12, and was of mixed colors. The P.I.R. flakes were made from scrap
laundry
detergent lids and other scrap polypropylene items.
1003791 The flakes were combined with 2 weight percent of green olefin color
and
were then pelletized (reground) using a twin-screw extruder.
1003801 Four plastic compositions were made having 0%, 25%, 50%, and 100% by
weight of the pelletized P.I.R., 2% by weight of weight Ilydrocerol* Bill 70
foaming
agent, and the remainder being virgin polypropylene.
1003811 Each of the four compositions was used to mold a brick on an Engel Duo
340
Ton injection molding machine (available from. Engel Machinery Inc. of York,
PA, USA)
using a mold having a cuboid cavity of 5.715 cm by 9.842 cm by 20.32 cm. A
total of 60
bricks was molded from the polypropylene made of 100% by weight P.I.R.
1003821 Process parameters for the MFIM process are shown in TABLE 44:
TABLE 44: Settings
Weight injectio
Shot Cooling Hold Hold Clamp
percent Decompression n speed
Volume Time Pressur Time Force
of Volume (cm) (cm3/se
(cm') (sec) e (kPa) (sec)
(kN)
P.I.R. c)
0 565 32.8 300 246 0 1
996
2,5 549 32.8 300 246 0 1
996
50 541 32.8 300 246 0 1
996
100 533 32.8 300 246 0 1
996
1003831 Four bricks, one made from of each composition, were cut to reveal a
cross
section and the foam structure of the brick. The four cross sections were
photographed,
and the photographs are shown in FIG. 74 along with magnified views of a cross
section
from a brick made from 100% virgin polypropylene and a cross section of a
brick made
109
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
from 100% P.I.R. The average internal cell size appeared to increase with
increasing
P.I.R. content.
Example 24
1003841 Two parts were foam molded using a blend of low-density polyethylene
blended with 2.5% by weight Hydrocerol 131H 70 foaming agent (available from
Clariant AG of Muttenz, Switzerland). Molding was conducted using an Engel
Victory
160 Ton injection molding machine (available from Engel Machinery. Inc. of
York, PA,
USA). The mold included a cylindrical cavity of 6.35 cm diameter and 5.717 cm
height
for a total volume of 180.33 em3. An aluminum mold having a cold sprue and
runner
system feeding the described cylinder shape was employed for both parts. The
melt
delivery system. for each part was the same, and the only process set-point
differing
between the two parts was the decompression time.
1003851 The process settings used to produce each part are detailed in TABLE
45. A
first part (Part 119) was molded using an MFIM process with 1800 seconds of
calculated
decompression time and a decompression volume of 14.75 cc. A second part (part
120)
was molded using an MF1.114 process with 0 seconds of calculated decompression
time.
The screw was not translated backwards to allow a decompression volume.
Accordingly,
the decompression volume was 0 cc.
110
CA 03223228 2023- 12- 18
WO 2023/277935
PCT/US2021/049200
TABLE 45: Settings, Part 119 and Part /20
Part 119 Part 120
Barrel Temperatures ( C) 182.2 1 182.2 1182.2 1 182.2 1
148.9 1 137.8 1 37.8
Mold Temperature ( C) 10
Injection Speed (eels) 327.7
Back Pressure (kPa) 6895
Decompression Time (sec) 1800 0
Decompression Volume (cc) 14.75 0
Decompression Rate (cc/0 163.9
____________________________________ =
Depressurization Rate (GPa/s) 0.0654
Cooling Time (sec) 1952 152
Shot Volume (cc) 65.55
Final Part Weight (g) 48.19 34.74
1003861 Part
119, formed using the molding process having a decompression
volume of 14.75 cc and a decompression time of 1800 seconds, was completely
filled out
and the shape of the part matched the shape of the mold cavity.
1003871 Part 120, formed using the process with no decompression tiin,e did
not yield
a part that filled the mold cavity. The part was sunken. in around the molded
flat portion
of the cylinder shape, and the part did not match the shape of the cavity of
the mold.
111
CA 03223228 2023- 12- 18
