Note: Descriptions are shown in the official language in which they were submitted.
670
mis invention relates to porous polymer structures
and a method of preparing the same. More particularly, this
invention relates to microporous polymer structures that may
be readily prepared and are characterized by relatively homo-
geneous, three-dimensional, cellular microstructures and to a
unique, facile process for preparing microporous polymer
structures.
Several widely differing techniques have been pre-
viously developed for preparing microporous polymer struc-
tures. Such techniques range from what is termed, in the art,classical phase inversion, to nuclear bombardment, to incor-
poration of microporous solid particles in a substrate which
are subsequently leached out, to sintering microporous
particles together in some fashion. Prior efforts in the field
have entailed still other techniques as well as innummerable
variations of what may be considered as the classical or basic
techniques.
m e interest in microporous polymer products has
been engendered by the numerous potential applications for
materials of this type. mese potential applications are
well knwon and range from ink pads, or the like, to leather-
like breathable sheets, to filter media. Yet, with all of the
potential applications, the commercial usage has been rela-
tively modest. And, the techniques being commercially uti-
lized have various limitations which do not allow the versa-
tility required to expand the applications to reach the po-
tential market for microporous products.
As mentioned, some commercially available micro-
porous polymer products are made by a nuclear bombardment
technique. Such a technique is capable of achieving a rather
narrow pore size distribution, however, the pore volume must
l~Z~670
be relatively low (i.e. - less than about 10% void space) to
insure that the polymer will not be degraded during prepara-
tion. Many polymers cannot be utilized in such a technique
due to the lack of the ability of the polymer to etch. Still
further, the technique requires that a relatively thin sheet
or film of the polymer be used and considerable expertise
must be employed in carrying out the procedure to avoid
"double tracking", which results in the formation of oversized
pores.
Classical phase inversion has also been commercial-
ly utilized to form microporous polymers from cellulose ace-
tate and certain other polymers. Classical phase inversion
has been reviewed in great detail by R.E. Kesting in SYNTHETIC
POLYMERIC MEMBRANES, McGraw-Hill, 1971. In particular at
page 117 of said reference it is explicitly stated that
classical phase inversion involves the use of at least three
components, a polymer, a solvent for said polymer and a non-
solvent for said polymer.
Reference may also be made to U.S. Patent No.
3,945,926 which teaches the formation of polycarbonate resin
membranes from a casting solution containing the resin, a sol-
vent, and a swelling agent and/or a nonsolvent. It is stated
at lines 42-47, column 15, of said patent that in the complete
absence of a swelling agent phase inversion usually does not
occur and that with low concentrations of swelling agents,
structures possessing closed cells are encountered.
From the foregoing discussion it is quite apparent
that classical phase inversion requires the use of a solvent
for the system at room temperature so that many other useful
polymers cannot be substituted for the polymers such as cellu-
lose acetate. Also from the process standpoint, the classical
)670
phase inversion process will generally be restricted to the
formation of films due to the large amount of solvent used in
the preparation of solutions which must be subsequently ex-
tracted. It is also apparent that classical phase inversion
requires a relatively high degree of process control to obtain
structures of desired configuration. Thus the relative con-
centrations of solvent, nonsolvent, and swelling agent must
be critically controlled, as discussed in column 14-16 of
U.S. Patent No. 3,945,926. Conversely, to alter the number,
size, and homogeneity of the resultant structure, one must
modify the aforementioned parameters by trial-and-error.
Other commercially available microporous polymers
are made by sintering microporous particles of polymers rang-
ing from high density polyethylene to polyvinylidene fluoride.
However, it is difficult with such a technique to obtain a
product with the narrow pore size distribution required for
many applications.
A still further general technique which has been
the subject of considerable prior effort involves heating a
polymer with various liquids to form a dispersion or solution
and thereafter cooling, followed by removal of the liquid
with a solvent or the like. This type of process is disclosed
in the following United States patents which are only repre-
sentative and not cumulative: 3,607,793; 3,378,507, 3,310,505,
3,748,287, 3,536,796, 3,308,073, and 3,812,224. It is not
believed that the foregoing technique has been utilized com-
mercially to any significant extent, if at all, probably due
to the lack of economic feasibility of the particular pro-
cesses which have previously been developed. Also, the
prior processes do not allow the preparation of microporous
polymers which combine relatively homogeneous microcellular
11'~,~670
.
structures with the pore size and pore size distributions
which are typically desired.
With respect to the microporous polymers obtained
by prior art techniques, no process known heretofore has been
capable of yielding isotropic olefinic or oxidation polymers
which have the major portion of pore sizes in the range of
about 0.1 to about 5 microns while having a relatively
narrow pore size distribution, thus exhibiting a high degree
of pore size uniformity throughout a sample thereof. Some
', 10 prior art olefinic or oxidation polymers have had pore sizes
in the foregoing range, but without a relatively narrow
pore size distribution, thus making such materials without
significant value in application areas, such as filtration,
which require a high degree of selectivity. Furthermore, prior
microporous olefinic or oxidation polymers which may be con-
sidered to have relatively narrow pore size distributions have
had absolute pore sizes which are outside the aforementioned
range, usually having substantially smaller pore sizes, for
use in application areas such as ultra-filtration. Finally,
some prior art olefinic polymers have had pore sizes in the
foregoing range and what may be considered to be relatively
narrow pore size distributions. However, such materials
have been made by use of techniques, such as stretching which
impart a high degree of orientation to the resultant anisotro-
pic material, rendering it undesirable for many application
areas. There thus has existed a need for microporous olefinic
and oxidation polymers having a pore size in a range of from
about 0.1 to about 5 microns and characterized as having a
relatively narrow isotropic pore size distribution.
A1SQ, a major drawback of many microporous polymers
available heretofore has been the low flow rate of such poly-
0670
mers when used in structures such as microfiltration membranes.
One of the major reasons for such low flow rates is the typi-
cally low void volume of many such polymers. Thus, perhaps
20 percent of the polymer structure, or less, may be "void"
volume through which a filtrate may flow, the remaining 80
percent of the structure being the polymer resin which forms
the microporous structure. Thus, there has also existed a
need for microporous polymers having a high degree of void
volume, especially with respect to olefinic polymers.
The Japanese patent disclosure number 105293/75
published on August 19, 1975,discloses a highly advantageous
method for converting a particular type of liquid amine anti-
static agent to a material which behaves as a solid. The ad-
vantages in processing which result are real and significant.
It would be similarly beneficial to be able to convert other
useful functional liquids such as flame retardants and the
like to materials which behave as solids.
It is accordingly an object of the present invention
to provide microporous polymer products chaxacterized by
relative homogeneity and narrow pore size distributions.
Another object is to provide a facile process which
allows the economic production of microporous polymers.
A still further object lies in the provision of a
process for making microporous polymer products, which has
applicability to a wide number of useful thermoplastic poly-
mers. A related and more specific object is to provide such
a process which is capable of readily forming microporous po-
lymers from any synthetic thermoplastic polymer including
polyolefins, condensation polymers and oxidation polymers.
Yet another object of this invention is to provide
microporous polymers in structures ranging from thin films to
.. . ..
liZ~670
; relatively thick blocks. A related object is to provide the
ability to form microporous polymers in intricate shapes.
A further object is to provide the conversion of
functional liquids to materials which possess the character-
istics of a solid.
In accordance with the invention, there is provided
an isotropic microporous polymer structure comprising a syn-
thetic thermoplastic polymer selected from the group consist-
ing of olefinic polymers, oxidation polymers, and blends
thereof. The polymer structure has an average pore diameter
of from about 0.1 to about 5 microns and an S value of from
about 1 to about 10.
Other objects and advantages of the present inven-
tion will become apparent from the following discussion, and
from the drawings, in which:
Figure 1 is a graph of temperature vs. concentration
for a hypothetical polymer-liquid system, setting forth the
binodial and spinodal curves, and illustrating the concentra-
tion necessary to achieve the microporous polymers and to
practice the process of the present invention
Figure lA is a graph of temperature vs. concentra-
tion similar to that of Figure 1, but also including the
freezing point depression phase line;
Figure 2 is a photomicrograph, at 55X amplification,
showing the macrostructure of a polypropylene microporous
polymer of the present invention with about a 75 per cent
void volume,
Figures 3 through 5 are photomicrographs of the
microporous polypropylene structure of Figure 2 at, respective-
ly, 550X, 2200X and 5500X amplification, and illustrate a
homogeneous cellular structure;
llZ(~670
Figures 6 through 10 are photomicrographs at, res-
pectively, 1325X, l550X, 1620X, 1450X and 1250X amplification
of additional microporous polypropylene structures and show
the modifications in the structure as the void space is
reduced from 90%, to 70%, to 60%, to 40%, and to 20%, res-
pectively;
Figures 11 through 13 are photomicrographs at, res-
-6a-
3670
pectively, 2000X, 2050X and 1950X amplification of still fur-
ther microporous polypropylene structures of the present in-
vention and illustrate the decreasing cell size as the poly-
propylene content is increased from the 10% by weight level
in Figure 11, to 20%, and to 30%, in Figures 12 and 13, res-
pectively,
Figures 14 through 17 are photomicrographs at, res-
pectively, 250X, 2500X, 2500X and 2475X amplification of
microporous low density polyethylene structures of the present
invention, Figures 14 and 15 showing the macro- and micro-
structure of a microporous polymer containing 20% by weight
polyethylene and Figures 16 and 17 showing the microstructure
with 40% and 70% polyethylene respectively,
Figures 18 and 19 are photomicrographs at, respect-
ively, 2100X and 2000X amplification of microporous high den-
sity polyethylene structures of the present invention and il-
luætrate the structures at 30% and 70% by weight polyethylene,
respectively.
Figures 20 and 21 are photomicrographs, at, respect-
ively, 2550X and 2575X amplification of microporous SBR poly-
mers of the present invention and show a homogeneous cellular
structure,
Figure 22 is a photomicrograph at 2400X amplifica-
tion of a microporous methylpentene polymer,
Figures 23 and 24 are photomicrographs at, respect-
ively, 255X and 2550X amplification of a microporous ethylene-
acrylic acid copolymer
Figure 25 is a photomicrograph at 2500X amplifica-
tion of a microporous polymer formed from a polyphenylene
oxide-polystyrene blend,
Figure 26 is a photomicrograph at 2050X amplifica-
llZ06~0
tion and illustrates a polystyrene microporous polymer;
Figure 27 is a photomicrograph at 2000X amplifica-
tion and showing a polyvinylchloride microporous polymer,
Figures 28 and 29 are photomicrographs at 2000X am-
plification of low density polyethylene microporous polymers
and showing the partial masking of the basic structure by the
"foliage" mode structure:
Figures 30 to 33 are mercury intrusion curves of
microporous polypropylene structures of the present invention
and illustrating the narrow pore diameter distribution which
is characteristic of the polymers of the instant invention;
Figures 34 to 40 are mercury intrusion curves of
commercial microporous products including "Celgard"* poly-
propylene (Fig. 34), "Amerace* A20" and "Amerace*A30" poly-
vinyl chloride (Figs. 35 and 36 respectively), "Porex" poly-
propylene (Fig. 37), "Millipore* BDWP 29300" cellulose ace-
tate (Fig. 38), "Gelman TCM-200" cellulose triacetate and
"Gelman Acropor WA" acrylonitrile-polyvinyl chloride copoly-
mer (Figs. 39 and 40 respectively),
Figures 41 through 43 are mercury intrusion curves
of microporous structures made in accordance with U.S.
3,378,507, using polyethylene (Figs. 41 and 42) and poly-
propylene (Fig. 43),
Figure 44 is a mercury intrusion curve of a poly-
ethylene microporous material made in accordance with U.S.
3,310,505,
Figures 45 to 46 are photomicrographs of a porous
polyethylene product prepared by duplicating Example 2 of
3,378,507 using an injection molding technique, Fig. 45
(240X amplification) showing the macrostructure and FigO 46
* Trade Mark
6~0
(2400X amplification) showing the microstructure,
Figures 47 to 48 are photomicrographs of a porous
polyethylene product prepared by duplicating Example 2 of
U.S. 3,378,507 using a compression molding technique, Fig.
47 (195X amplification3 showing the macrostructure and Fig.
48 (2000X amplification) showing the microstructure,
Figures 49 to 50 are photomicrographs of a porous
polypropylene product prepared by duplicating Example 2 of
U.S. 3,378,507 using an in]ection molding technique, Fig. 49
(195X amplification) showing the macrostructure and Fig. 50
(2000X amplification) showing the microstructure,
Figures 51 to 52 are photomicrographs of a porous
polypropylene product prepared by duplicating Example 2 of
U.S. 3,378,507 using a compression molding technique, Fig. 51
(206X amplification) showing the macrostructure and Fig. 52
(2000X amplification) showing the microstructure, and
Figures 53 to 54 are photomicrographs of a porous
polyethylene product prepared by duplicating Example 2 of
U.S. 3,310,505, Fig. 53 (205 amplification) showing the macro-
structure and Fig. 54 (200X amplification) showing the micro-
structure:
Figure 55 shows a melt curve and a crystallization
curve for a polypropylene and quinoline polymer/liquid system;
Figure 56 shows a melt curve and several crystalli-
zation curves for a polypropylene and N,N bis(2-hydroxyethyl~
tallow-amine polymer/liquid system,
Figure 57 shows a melt curve and a crystallization
curve for a polypropylene and dioctyl phthalate polymer/liquid
system, demonstrating a system which is not within the scope
of the present invention,
Figure 58 shows the phase diagram for a low molecu-
lar weight polyethylene and diphenyl ether polymer/liquid
l~Z~67~
system, determined at cooling and heating rates of 1C/minute,
Figure 59 shows several melt and crystallization cur-
ves for a low molecular weight polyethylene and diphenyl ether
polymer/liquid system;
Figure 60 shows a glass transition curve for a low
molecular weight polystyrene and 1-dodecanol polymer/liquid
system,
Figure 61 is a photomicrograph at 5000X amplifica-
tion of a 70 per cent void microporous cellular structure of
the present invention, made from polymethylmethacrylate,
Figure 62 shows melt and crystallization curves for
a Nylon 11 and tetramethylene sulfone polymer/liquid system,
Figure 63 is a photomicrograph at 2000X amplifica-
tion of a 70 per cent void microporous cellular structure of
the present invention, made from Nylon 11;
Figure 64 is a photomicrograph at 2000X amplifica-
tion of a 70 per cent void microporous cellular structure of
the present invention, made from polycarbonate,
Figure 65 is a photomicrograph at 2000X amplifica-
tion of a 70 per cent void microporous cellular structure of
the present invention, made from polyphenylene oxide,
Figures 66 and 67 are photomicrographs at 2000X am-
plification of a 60 per cent void and a 75 per cent void, res-
pectively, microporous non-cellular structure of the present
invention, made from polypropylene,
Figures 68 and 69 are, respectively, mercury intru-
sion curves of a 60 per cent void and a 75 per cent void non-
cellular microporous polypropylene structure within the scope
of the present invention,
Figure 70 is a graphical representation of the unique
microporous cellular structures of the present invention as
compared to certain prior art compositions.
--10--
llZ0670
While the invention is susceptible of various modifi-
cations and alternative forms, there will be herein described
in detail the preferred embodiments. It is to be understood,
however, that it is not intended to limit the invention to
the specific forms disclosed. On the contrary, it is intended
to cover all modifications and alternative forms falling with-
in the spirit and scope of the invention as expressed in the
appended claims.
It has now been discovered that any synthetic
thermoplastic polymer may be rendered microporous by first
heating said polymer and a compatible liquid, discussed
hereinbelow, to a temperature and for a time sufficient to form
a homogeneous solution. me so formed solution is then allow-
ed to assume a desired shape and subsequently cooled in said
shape at-a rate and to a temperature sufficient so that
thermodynamic non-equilibrium liquid-liquid phase separation
is initiated. As the solution is cooled in the desired shape,
no mixing or other shear force is applied while the solution
is undergoing the cooling. ~he cooling is continued so that a
solid results. The solid needs only to attain sufficient
mechanical integrity to allow it to be handled, without caus-
ing physical degradation. Finally, at least a substantial
portion of the compatible liquid is removed from the resulting
solid to form the desired microporous polymer.
Certain novel microporous olefinic and oxidation
polymers of the present invention are characterized by a
narrow pore size distribution, as determined by mercury intru-
sion porosimetry. ~he narrow pore size distribution may be
analytically expressed in terms of a sharpness function "S"
which is explained in detail hereinbelow. me "S" values of
the olefinic and oxidation polymer of the present invention
--11--
;
670
range from about 1 to about 10. Also, said polymers of the
present invention are characterized by average pore sizes
which range from about 0.10 to about 5 microns about 0.2 to
about 1 micron being preferred. Furthermore, such microporous
products are substantially isotropic, and thus have essential-
ly the same cross-sectional configuration when analyzed along
any spatial plane.
In another aspect of the present invention the
method of preparing microporous polymers is performed so that
a mixture comprising a synthetic thermoplastic polymer, es-
pecially a polyolefin, an ethylene-acrylic acid copolymer,
a polyphenylene oxide-polystyrene blend, or a blend of one or
more of the foregoing polymers, and a compatible liquid is
heated to a temperature and for a time sufficient to form a
homogeneous solution. The solution is then cooled, thus
forming at substantially the same time a plurality of liquid
droplets of substantially the same size. me cooling is then
continued to solidify the polymer and at least a substantial
portion of the liquid is removed from the resulting solid to
form the desired cellular polymer structure.
The foregoing method will result in microporous
polymer products characterized by a cellular, three-dimension-
al, void microstructure, i.e. - a series of enclosed cells
having substantially spherical shapes and pores or passage-
ways interconnecting adjacent cells. me basic structure is
relatively homogeneous with the cells being uniformly spaced
throughout the three dimensions, and the interconnecting pores
have diameters which are relatively narrow in size distribu-
tion as measured by mercury intrusion. For ease of reference,
microporous polymers having such a structure will be referred
to as "cellular".
ll'~S7~
A related aspect of this invention provides novel
microporous polymer products which behave as solids and con-
tain relatively large amounts of functionally useful liquids
such as, for example, polymer additives including flame re-
tardants and the like. In this fashion, useful liquids may
obtain the processing advantages of a solid material which
may be used directly, as for example, in a master batch.
Such products may be formed directly by using a functional
liquid as the compatible liquid and not carrying out the re-
moval of the compatible liquid or indirectly by either re-
loading the microporous polymer after the removal of the com-
patible liquid or displacing the compatible liquid before
removal to incorporate the functional liquid.
Broadly, the practice of the process of the instant
invention involves heating the desired polymer with an appro-
priate compatible liquid to form a homogeneous solution, cool-
ing said solution in an appropriate manner to form a solid
material and subsequently extracting the liquid to form a
microporous material.~ The considerations involved in prac-
ticing the instant invention will be described in detail here-
inbelow.
As indicated, the present invention surprisingly
affords a technique for rendering any synthetic thermoplastic
polymer microporous. Thus, the process of the present inven-
tion applies to olefinic polymers, condensations polymers, and
oxidation polymers.
Exemplary of the useful non-acrylic polyolefins are
low density polyethylene, high density polyethylene, poly-
propylene, polystyrene, polyvinylchloride, acrylonitrile-
butadiene-styrene terpolymers, styrene-acrylonitrile copoly-
mers, styrene butadiene copolymers, poly ~4-methyl-pentene-1),
-13-
11'~(~6 ~'0
~'
polybutylene, polyvinylidene chloride, polyvinyl butyral,
chlorinated polyethylene, ethylene-vinyl acetate copolymers, -
polyvinyl acetate, and polyvinyl alcohol.
Useful acrylic polyolefins include polymethyl-
methacrylate, polymethyl-acrylate, ethylene-acrylic acid co-
polymers, and ethylene-acrylic acid metal salt copolymers.
Polyphenylene oxide is representative of the oxida-
tion polymers which may be utilized. The useful condensa-
tion polymers include polyethylene terephthalate, polybutylene
terephthalate, Nylon 6, Nylon 11, Nylon 13, ~ylon 66, poly-
carbonates and polysulfone.
Thus, to practice the present invention one need
only first choose the synthetic thermoplastic polymer which is
to be rendered microporous. Having selected the polymer, the :
next procedure is the selection of the appropriate compatible
liquid and the relative amounts of polymer and liquid to be
utilized. Of course blends of one or more polymers may be
utilized in the practice of the present invention. Function-
ally, the polymer and liquid are heated with stirring up to
the temperature required to form a clear, homogeneous solu-
tion. If a solution cannot be formed at any liquid concen-
tration, then the liquid is inappropriate and cannot be
utilized with that particular polymer.
Because of the selectivity, absolute predictability
for predetermining the operability of a particular liquid
with a particular polymer is not possible. However, some use-
ful general guidelines can be set forth. Thus when the poly-
mer involved is non-polar, non-polar liquids with similar
solubility parameters at the solution temperature are more
likely to be useful. When such parameters are not available,
one may refer to the more readily available room temperature
solubility parameters, for general guidance. Similarly, with
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llZ~670
polar polymers, polar organic liquids with similar solubility
parameters should be initially examined. Also, the relative
polarity or non-polarity of the liquid should be matched with
the relative polarity or non-polarity of the polymer. In ad-
dition, with hydrophobic polymers, useful liquids will typic-
ally have little or no water solubility. On the other hand,
polymers which tend to be hydrophilic will generally require
a liquid having some water solubility.
With respect to appropriate liquids, particular
species of various types of organic compounds have been found
useful, including aliphatic and aromatic acids, aliphatic,
aromatic and cyclic alcohols, aldehydes, primary and secondary
amines, aromatic and ethoxylated amines, diamines, amides,
esters and diesters, ethers, ketones and various hydrocarbons
and heterocycles. It should, however, be noted that the con-
cept is quite selective. Thus, for example, not all saturated
aliphatic acids will be useful, and, further, not all liquids
useful for high density polyethylene will necessarily be use-
ful for, as an example, polystyrene.
As will be appreciated, the useful proportions of
polymer and liquid for any particular system can readily be
developed from an evaluation of the parameters which will be
discussed subsequently.
Where blends of one or more polymers are used, as
should be understood, useful liquids must typically be oper-
able with all of the polymers included. It may however be
possible for the polymer blend to have characteristics such
that the liquid need not be operable with all polymers used.
As one example, where one or more polymeric constituents are
present in such relatively small amounts as to not signifi-
cantly affect the properties of the blend, the liquid employed
~lZ0670
need only be cperable with the principal polymer or polymers.
Also, while most useful materials are liquids at
ambient temperatures, materials which are solid at room tem-
perature may be employed so long as solutions can be formed
with the polymer at elevated temperatures and the material
does not interfere with the formation of the microporous
structure. More specifically, a solid material may be used
so long as phase separation occurs by liquid-liquid separa-
tion rather than liquid-solid separation during the cooling
step which will hereinafter be discussed. The amount of li-
quid used can be, in general, varied from about 10 to about
90%.
As presently discussed any synthetic thermoplastic
polymer may be employed so long as the liquid selected forms
a solution with the polymer and the concentration yields a
continuous polymer phase upon separation during cooling, as
will be discussed in more detail hereinafter. So that one may
appreciate the range of operable polymer and liquid systems,
a brief summary of some of such systems may be useful.
In forming microporous polymers from polypropylene,
alcohols such as 2-benzylamino-1-propanoi and 3-phenyl-1-
propanol, aldehydes such as salicylaldehyde: amides such as
N,N-diethyl-m-toluamide, amines such as N-hexyl diethanolamine,
N-behenyl diethanol amine, N-coco-diethanolamine, benzyl amine,
N,N-bis-~ -hydroxyethyl cyclohexyl amine, diphenyl amine and
1,12 - diamino dodecane; esters such as methyl benzoate,
benzyl benzoate, phenyl salicylate, methyl salicylate and
dibutyl phthalate, and ethers such as diphenyl ether, 4-
bromo-diphenyl ether and dibenzyl ether have been found use-
ful. In addition, halocarbons such as 1,1,2,2-tetrabromo-
ethane and hydrocarbons such as trans-stilbene and other
-16-
l~Z~6t70
alkyl/aryl phosphites are also useful as are ketones such as
methyl nonyl ketone.
In forming microporous polymers from high density
polyethylene, a saturated aliphatic acid such as decanoic
acid, primary saturated alcohols such as decyl alcohol, and
l-dodecanol, secondary alcohols such as 2-undecanol and 6-
undecanol, ethoxylated amines such as N-lauryldiethanolamine,
aromatic amines such as N,N-diethylaniline, diesters such as
dibutyl sebacate and dihexyl sebacate and ethers such as di-
phenyl ether and benzyl ether have been found useful. Otheruseful liquids include halogenated compounds such as octa-
bromodiphenyl, hexabromobenzene and hexabromocyclodecane,
hydrocarbons such as l-hexadecane, diphenylmethane and naph-
thalene, aromatic compounds such as acetophenonone and other
organic compounds such as alkyl/aryl phosphites, and quino-
line and ketones such as methylnonyl ketone.
To form microporous polymers from low density poly-
ethylene, the following liquids have been found useful: satur-
ated aliphatic acids including hexanoic acid, caprylic acid,
decanoic acid, undecanoic acid, lauric acid, myristic acid,
palmitic acid and stearic acid, unsaturated aliphatic acids
including oleic acid and erucic acid, aromatic acids including
benzoic acid, phenyl stearic acid, polystearic acid and
xylyl behenic acid and other acids including branched car-
boxylic acids of average chain lengths of 6, 9, and 11 car-
bons, tall oil acids and rosin acid, primary saturated alco-
hols including l-octanol, nonyl alcohol, decyl alcohol, 1-
decanol, l-dodecanol, tridecyl alcohol, cetyl alcohol and
l-heptadecanol, primary unsaturated alcohols including un-
decylenyl alcohol and oleyl alcohol, secondary alcohols in-
cluding 2-octanol, 2-undecanol, dinonyl carbinol and diun-
decyl carbinol and aromatic alcohols including l-phenyl
-17-
llZ~6~0
ethanol, l-phenyl~l-pentanol, nonyl phenol, phenyl-stearyl
alcohol.and l-napthol. Other useful hydroxyl-containing
compounds include polyoxyethylene ethers of oleyl alcohol
and a polypropylene glycol having a number average molecular
weight of about 400. Still further useful liquids include
cyclic alcohols such as 4, _-butyl cyclohexanol and menthol,
alkehydes including salicyl aldehyde, primary amines such as
octylamine, tetradecylamine and hexadecylamine, secondary
amines such as bis-(l-ethyl-3-methyl pentyl~ amine and
ethoxylated amines including ~-lauryl diethanolamine, ~-tallow
diethanol-amine, ~-stearyl diethanolamine and N-coco diethanol-
amine.
Additional useful liquids comprise aromatic amines
including ~-sec-butylaniline, dodecylaniline, ~,N-dimethyl-
aniline, N,N-diethylaniline, ~-toluidine, N-ethyl-o-toluidine,-
diphenylamine and aminodiphenylmethane, diamines including
~-erucyl-1,3-propane diamine and 1,8-diamino-p-menthane, other
amines including branched tetramines and cyclododecylamine,
amides including cocoamide, hydrogenated tallow amide, octa-
decylamide, eruciamide, N,N-diethyl toluamide and N-trimethylol-
propane stearamide, saturated aliphatic esters including
methyl caprylate, ethyl laurate, isopropyl myristate, ethyl
palmitate, isopropyl palmitate, methyl stearate, isobutyl
stearate and tridecyl stearate, unsaturated esters including
stearyl acrylate, butyl undecylenate and butyl oleate, alkoxy
esters including butoxyethyl stearate and butoxyethyl oleate,
aromatic esters including vinyl p~enyl stearate, isobutyl
phenyl stearate, tridecyl phenyl stearate, methyl benzoate,
ethyl benzoate, butyl benzoate, benzyl benzoate, phenyl laur-
ate, phenyl salicylate, methyl salicylate and benzyl acetateand diesters including dimethyl phenylene distearate, diethyl
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11'~g~61~0
phthalate, dibutyl phthalate, di-iso-octyl phthalate, di-
capryl adipate, dibutyl sebacate, dihexyl sebacate, di-iso-
octyl sebacate, dicapryl sebacate and dioctyl maleate. Yet
other useful liquids comprise polyethylene glycol esters in-
cluding polyethylene glycol (having a number of average
molecular weight of about 400), diphenylstearate, polyhydro-
xylic esters including castor oil (triglyceride), glycerol
monostearate, glycerol monooleate, glycerol distearate glycerol
dioleate and trimethylol propane monophenylstearate, ethers
including diphenyl ether and benzyl ether, halogenated com-
pounds including hexachlorocyclopentadiene, octabromobiphenyl,
decabromodiphenyl oxide and 4-bromodiphenyl ether, hydrocarbons
including l-nonene, 2-nonene, 2-undecene, 2-heptadecene, 2-
nonadecene, 3-eicosene, 9-nonadecene, diphenylmethane, tri-
phenylmethane and trans-stilbene, aliphatic ketones including
2-heptanone, methyl nonyl ketone, 6-undecanone, methylundecyl
ketone, 6-tridecanone, 8-pentadecanone, ll-pentadecanone, 2-
heptadecanone, 8-heptadecanone, methyl heptadecyl ketone, di-
nonyl ketone and distearyl ketone, aromatic ketones including
acetophenone and benzophenone and other ketones including
xanthone. Still further useful liquids comprise phosphorous
compounds including trixylenyl phosphate, polysiloxanes, Muget
hyacinth (An Merigenaebler, Inc), Terpineol Prime No. 1 (Gi-
vaudan-Delawanna, Inc), Bath Oil Fragrance No. 5864 K (In-
ternational Flavor & Fragrance, Inc), Phosclere* P315C
(organophosphite), Phosclere P576 (organophosphite), styren-
ated nonyl phenol, quinoline and quinalidine.
To form microporous polymer products with polystyrene,
useful liquids include tris-halogenated propylphosphate, aryl/
alkyl phosphites, 1,1,2,2, tetrabromoethane, tribromoneo-
* Trade Mark
--19--
l~Z0670
pentylalcohol, 40% Voranol* C.P. 3000 polyol and tribromoneo-
pentyl alcohol 60%, tris- ~-chloroethylphosphate, tris (1,3-
dichloroisopropyl) phosphate, tri-(dichloropropyl) phosphate,
dichlorobenzene, and l-dodecanol.
In forming microporous polymers using polyvinyl
chloride, useful liquids comprise aromatic alcohols including
methoxy benzyl alcohol, 2-benzylamino-1-propanol, and other
hydroxyl-containing liquids including 1,3-dichloro-2-propanol.
Still other useful liquids comprise halogenated compounds in-
cluding Firemaster* T33P (tetrabromophthalic diester), andaromatic hydrocarbons including trans-stilbene.
In addition, in accordance with the present inven-
tion, microporous products have been made from other polymers
and copolymers and blends. mus, to form microporous products
from styrene-butadiene copolymers, useful liquids include decyl-
alcohol, ~-tallow diethanol amine, ~-coco diethanol amine and
diphenyl amine. Useful liquids for forming microporous poly-
mers from ethylene-acrylic acid copolymer salts include N-
tallow diethanolamine, ~-coco diethanolamine, dibutyl phthalate
and diphenyl ether. Microporous polymer products using high
impact polystyrene can be formed by employing as liquids, hexa-
bromobiphenyl and alkyl/aryl phosphites. With "Noryl"* poly-
phenylene oxide-polystyrene blends (General Electric Company),
microporous polymers can be made utilizing ~-coco diethanol
amine, ~-tallow diethanol-amine, diphenylamine, dibutyl phtha-
late and hexabromophenol. Microporous polymers from blends of
low density polyethylene and chlorinated polyethylene can be
made by utilizing l-dodecanol, diphenyl ether and N-tallow di-
ethanolamine. Utilizing l-dodecanol as the liquid, microporous
polymer products can be made from the following blends: poly-
* Trade Mark
-20-
~lZV670
propylene-chlorinated polyethylene, high density polyethylene-
chlorinated polyethylene, high density polyethylene-polyvinyl
chloride and high density polyethylene and acrylonitrile-
butadiene-styrene ~ABS) terpolymers. To form microporous
products from polymethyl-methacrylate, 1-4,butanediol and
lauric acid have been found to be useful. Microporous Nylon
11 may be made utilizing ethylene carbonate, 1,2-propylene
carbonate, or tetramethylene sulfone. Also, menthol may be
utilized to form microporous products from polycarbonate.
The determination of the amount of the liquid used is
obtained by reference to the binodial and spinodial curves
for the system, illustrative curves being set forth in Fig. 1.
As shown therein, Tm represents the maximum temperature of
the binodial curve (i.e. - the maximum temperature of the
system at which binodial decomposition will take place), T
represents the upper critical solution temperature (i.e. - the
maximum temperature at which spinodal decomposition will take
place), ~m represents the polymer concentration at Tm~ ~c
denotes the critical concentration and ~x represents the
polymer concentration of the system needed to obtain the
unique microporous polymer structures of the present inven-
tion. meoretically, ~m and ~ should be virtually identical;
however, as is known, due to molecular weight distributions
of commercially available polymers, ~c may be about 5% by
weight or so greater than the value of ~m~ To form the
unique microporous polymers of the present invention, the poly-
mer concentration utilized for a particular system ~x' must be
greater than ~c If the polymer concentration is less than
~c~ the phase separation which will occur as the system is
cooled will constitute a continuous liquid phase with a dis-
continuous polymer phase. On the other hand, utilizing the
-21-
l~a67v
proper polymer concentration will insure that the continuous
phase, which will be formed upon cooling to the phase sepa-
ration temperature, will be the polymer phase, as is required
to obtain the unique microcellular structures of the present
invention. Likewise, as will be apparent, the formation of
a continuous polymer phase upon phase separation requires that
a solution be initially formed. When the process of the pre-
sent invention is not followed and a dispersion is initially
formed, the resulting microporous product is similar to that
achieved by sintering together polymer particles.
Accordingly, as will be appreciated, the applicable
polymer concentration or amount of liquid which may be uti-
lized, will vary with each system. Suitable phase diagram
curves for several systems have already been developed. How-
ever, if an appropriate curve is not available, this can be
readily developed by known techniques. For example, a suit-
able technique is set forth in Smolders, van Aartsen and
Steenbergen, Kolloid - Z. u. Z. Polymere, 243, 14 (1971).
A more general graph of temperature vs. concentra-
tion for a hypothetical polymer-liquid system is given by
Fig. lA. me portion of the curve from ~ to ~ represents
thermodynamic equilibrium liquid - liquid phase separation.
The portion of the curve from ~ to ~ represents equilibrium
liquid-solid phase separation, which will be recognized as
the normal freezing point depression curve of a hypothetical
liquid-polymer system. me upper shaded area represents an
upper liquid~liquid immiscibility which may be present in some
systems. me dotted line represents the lowering of crystal-
lization temperature as a consequence of cooling at a rate
sufficient to achieve thermodynamic non-equilibrium liquid-
liquid phase separation. ~he flat portion of the crystalliza-
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112~6~70
tion vs. composition curve defines a useable composition range
which is a function of the cooling rate employed, as will be
discussed in more detail.
Thus, for any given cooling rate, one may plot the
crystallization temperature vs. percentage resin or compatible
liquid and in such a manner determine the liquid/polymer con-
centration ranges which will yield the desirable microporous
structures at the given cooling rate. For crystalline poly-
mers, the determination of the useable concentration range via
the plotting of the aforementioned crystallization curve is a
viable alternative to determining a phase diagram, as shown in
Fig. 1. As an example of the foregoing, one may refer to
Fig. 55 which is a plot of temperature vs. polymer/liquid
concentration showing the melt curve at a heating rate of
16C per minute, and crystallization curve for polypropylene
and quinoline over a broad concentration range. As may be
seen by reference to the crystallization curve, at a cooling
rate of 16C per minute, the appropriate concentration range
extends from about 20 percent polypropylene to about 70 per-
cent polypropylene.
Fig. 56 is a graph of temperature versus polymer/liquid composition for polypropylene and ~,N-bis (2-hydroxy-
ethyl) tallowamine. The upper curve is a plot of the melt
curve at a heating rate of 16C per minute. The lower curves,
in descending order, are plots of the crystallization curves
at cooling rates of 8C, 16C, 32C, and 64C, per minute.
The curves demonstrate two concurrent phenomena which occur
when the cooling rate is increased. First, the flat portion
of the curve demonstrating a relative stable temperature of
crystallization across a broad concentration range, is lower-
ed with increased cooling rate showing that the faster the
rate of cooling, the lower the actual crystallization tem-
-23-
~12~670
perature.
The second observable phenomenon is the change in
the slope of the crystallization curve which occurs with chan-
ges in the rate of cooling. Thus, it appears that the flat
region of the crystallization curve is expanded when the
cooling rate is increased. Accordingly, one may assume that
by increasing the rate of cooling, one may correspondingly
increase the operable concentration range for forming the
microporous structures of the present invention and for
practicing the processes of the instant invention. From the
foregoing it is apparent that to determine the operable con-
centration ranges for a given system, one need only prepare
a few representative concentrations of polymer/liquid and
cool the same at some desired rate. After the crystalliza-
tion temperatures have been plotted, the operable range of
concentrations will be quite apparent.
Fig. 57 is a graph of temperature versus polymer/
liquid concentration for polypropylene and dioctyl phthalate.
The upper curve represents the melt curve for the system over
a range of concentrations and the lower curve represents the
crystallization curve over the same concentration range. As
the crystallization curve does not exhibit any flat region
over which the crystallization temperature remains substantial-
ly constant for a range of concentrations, one would not ex-
pect the polypropylene/dioctyl phthalate system to be capable
of forming microporous structures, and, indeed, it does not.
To appreciate the excellent correlation between the
phase diagram method of determining operable concentration ran-
ges of polymer and liquid and the crystallization method of
making such a determination, one may refer to Figs. 58 and 59.
Fig. 58 is a phase diagram for a low molecular weight poly-
-24-
112(~670
ethylene and diphenyl ether polymer/liquid system, determined
by a conventional light scattering technique utilizing a
thermally controlled vessel. From the phase diagram of Fig.
58, it appears that Tm is at about 135C and ~m is at about
7 percent polymer. Furthermore, it is apparent that at about
45 percent polymer concentration, the cloud point curve inter-
sects the freezing point depression curve, thus indicating an
operable concentration range of about 7 percent polymer to
about 45 percent polymer.
One may compare the operable range determined from
Fig. 58 to the range determinable from Fig. 59 which shows
melt curves of the same system at heating rates of 8C and
16C/minute and crystallization curves for said system at
cooling rates of 8C and 16C/minute. From the crystalliza-
tion curves it appears that the substantially flat portion
thereof extends from somewhat below 10 per cent polymer con-
centration to approximately 42-45 per cent polymer, depending
on the cooling rate. Thus, the results obtained from the
crystallization curves agree surprisingly well with the re-
sults obtained from the cloud point phase diagram.
For non-crystalline polymers it is believed that
one may refer to a temperature vs. concentration plot of the
glass transition temperature, as an alternative to referring
to a phase diagram such as that of Fig. 1. Thus, Fig. 60 is
a graph of temperature vs. concentration for the glass transi-
tion temperature of low molecular weight polystyrene, supplied
by Pennsylvania Industrial Chemical Corporation under the
designation Piccolastic* D-125, and l-dodecanol, at various
concentration levels.
From Fig. 60 it is apparent that from about 8 per-
* Trade Mark
-25-
~lZU670
cent polymer to about 50 percent polymer, the glass transi-
tion temperature for the polystyrene/l-dodecanol is essential-
ly constant. It has therefore been proposed that the concen-
trations along the substantially flat portion of the glass
transition curve would be operable in the practice of the
instant invention, analogous to the flat portion of the
crystallization curves previously discussed. It thus appears
that a viable alternative to determining the phase diagram
for non-crystalline polymer systems is to determine the glass
transition curve and to operate in the substantially flat
region of such a curve.
In all of the foregoing Figs., the crystallization
temperatures were determined with a DSC-2, differential scan-
ning calorimeter, manufactured by Perkin-Elmer, or comparable
equipment. Further effects of cooling rates as the practice
on the present invention will be discussed hereinbelow.
After one has chosen the desired synthetic thermo-
plastic polymer, the compatible liquid and the potentially
operable concentration range, one needs to choose, for example,
the actual concentration of polymer and liquid which will be
utilized. In addition to considering, for example, the
theoretically possible concentration range, other functional
considerations should be employed in determining the propor-
tions used for a particular system. mus, insofar as the
maximum amount of liquid which should be utilized is concerned,
the resulting strength characteristics must be taken into
account. More particularly, the amount of liquid used should
accordingly allow the resulting microporous structure to have
sufficient minimum "handling strength" to avoid collapse of
the m~croporous or cellular structure. On the other hand,
the selection of the maximum amount of resin, viscosity limi-
6~70
tations of the particular equipment utilized may dictate thetolerable maximum polymer or resin content. Moreover, the
amount of polymer used should not be so great as to result
in closing off the cells or other areas of microporosity.
The relative amount of liquid used will also, to
some extent, be dependent upon the desired effective size of
the microporosity, as, for example, the particular cell and
pore size requirements for the ultimate application involved.
Thus, for example, the average cell and pore size tend to
increase somewhat with increasing liquid content.
In any event, the utility of a liquid and the oper-
able concentration thereof, for a particular polymer, can be
readily determined by experimentally using the liquid as has
been described.
The parameters previously discussed should, of
course, be followed. Indeed, as should be appreciated, blends
of two or more liquids can be used, and the utility of a par-
ticular blend can be ascertained as described herein. Also,
while a particular blend may be useful, one or more of the
liquids may conceivably be unsuitable individually.
As may be appreciated, the particular amount of
liquid employed will likewise be often dictated by the par-
ticular end use application. As illustrative examples of spe-
cific examples, utilizing high density polyethylene and N,~-
bis(2-hydroxyethyl) tallowamine, useful microporous products
can be made by utilizing, by weight, from about 30 to about
90% amine, 30 to 70 being preferred. With low density poly-
ethylene and the same amine, the amount of liquid can useful-
ly be varied within the range from about 20 to 90%, 20 to 80
being preferred. In contrast, when diphenylether is used as
the liquid, useful low density polyethylene systems contain no
-27-
llZ~670
more than about 80% of the liquid, a maximum of about 60% being
preferred. When l-hexadecene is used with low density poly-
ethylene, amounts up to about 90% or more may be readily uti-
lized. When polypropylene is used with the tallowamine
previously described, the amine may be suitably employed in
amounts of from about 10 to 90%, with a maximum amount of no
more than about 85% being preferred. With polystyrene and 1-
dodecanol, the concentration of the alcohol can vary from about
20 to about 90%, with from about 30 to about 70% being pre-
ferred. When styrene-butadiene copolymers are employed, the
amine content may range from about 20 to about 90%. When a
decanol and styrene-butadiene copolymer (i.e. -SBR) system is
used, the liquid content can suitably vary from about 40 to
about 90%, with diphenylamine, the liquid content is suitable
within the range of from about 50 to about 80%. When micro-
porous polymers are formed from the amine and an ethylene-
acrylic acid copolymer, the liquid content may vary within the
range of from about 30 to about 70%, with diphenyl ether, the
liquid content may vary from about 10 to about 90%, as is the
case when dibutylphthalate is used as the solvent.
Following the formation of the solution, the same
may then be processed to provide any desired shape or configu-
ration. In general, and depending upon the particular system
involved, the thickness of the article can vary from a thin
film of about 1 mil. or less up to a relatively thick block of
thickness of about 2 1/2 inches or even more. me ability to
form blocks thus allows the microporous material to be proces-
sed into any desired intricate shape, as by using conventional
extrusion, injection molding or other related techniques. The
practical considerations involved in determining the range of
thicknesses which can be made from a particular system include
-28-
llZC~670
the rate of viscosity build-up which the system undergoes as it
cools. Generally, the higher the viscosity, the thicker the
structure can be. The structure can accordingly be of any
thickness so long as gross phase separation does not occur,
i.e. - 2 discernible layers become visually apparent.
It will be appreciated that if liquid-liquid phase
separation is allowed to take place under thermodynamic
equilibrium conditions the result will be a complete separa-
tion into two distinct layers. One layer consisting of molten
polymer containing the soluable amount of liquid and a liquid
layer containing the soluable amount of polymer in the liquid.
This condition is represented by the binodial line in the
phase diagram in Figs. 1 and lA. It is apparent that a limi-
tation as to the size of object which may be prepared is
governed by the heat transfer characteristics of the compo-
sition for if the object is thick enough and the heat trans-
fer is poor enough the rate of cooling in the center of the
object may be slow enough to approach thermodynamic equili-
brium conditions and result in a distinct layer phase separa-
tion as previously described.
Increased thicknesses may also be achieved by theaddition of minor amounts of thixotropic materials. For ex-
ample, the addition of commercially available colloidal sili-
ca prior to cooling significantly increases useful thicknesses
yet does not adversely affect the characteristic microporous
structure. The particular amounts to be used can be readily
determined.
As is apparent from the above discussion, regard-
less of the type of processing (e.g. - casting into a film or
the like), the solution must be cooled down to form what
behaves as, and appears as, a solid. The resulting material
-29-
ll'Z~670
should have sufficient integrity so that it will not crumble
upon handling, as in one's hand. A further test to ascertain
whether the requisite system possesses the desired structure
is to employ a solvent for the liquid employed but not for the
polymer. If the material disintegrates, the system employed
did not satisfy the necessary criteria.
The rate of cooling of the solution may be varied
within wide limits. Indeed, in the usual case, no external
cooling need be employed, and it is satisfactory merely to,
for example, cast a film by pouring the hot liquid system onto
a metallic surface heated to a temperature which allows the
drawing of the film or, alternatively, forming a block by
pouring onto a substrate at ambient conditions.
~ he rate of cooling, as previously discussed must
be sufficiently fast so that the liquid-liquid phase separa-
tion does not occur under thermodynamic equilibrium conditions.
` Furthermore, the rate of cooling may have substantial effect
upon the resultant microporous structure. For many polymer/
- liquid systems,if the rate of cooling is sufficiently slow,
but still satisfying the aforementioned criteria, then the
; liquid-liquid phase separation will result at substantially
the same time in the formation of a plurality of liquid drop-
lets of substantially the same size. If the cooling rate is
such that the plurality of liquid droplets does form, as long
as all other conditions discussed herein have been satisfied,
the resultant microporous polymer will have the cellular micro-
structure, as previously defined.
In general, it is believed that the unique struc-
tures of the microporous polymers of the present invention are
obtained by cooling the liquid system to a temperature below
the binodial curve, as shown in Fig. 1, so that liquid-liquid
-30-
~lZ~670
phase separation is initiated. At this state, nuclei will
begin to form, consisting principally of pure solvent. When
the rate of cooling is such that the cellular microstructure
results, it is also believed that as each such nucleus con-
tinues to grow, it becomes surrounded by a polymer-rich region
which increases in thickness as it becomes depleted of liquid.
Eventually, this polymer-rich region resembles a skin or film
covering the growing droplet of solvent. As the polymer-rich
region continues to thicken, the diffusion of additional sol-
vent through the skin decreases, and the growth of the liquiddroplet correspondingly decreases until it effectively stops,
the liquid droplet having reached its maximum size. At this
point, the formation of a new nucleus is more probable than
continued growth of the large solvent droplet. However, to
achieve this mode of growth, it is necessary that nucleation
be initiated by spinodal decomposition rather than by binodial
decomposition.
The cooling is thus carried out in such a fashion as
to form at substantially the same time a plurality of liquid
droplets of substantially the same size in a continuous poly-
mer phase~ If this decomposition mode does not take place, the
cellular structure will not result. The-appropriate decompo-
sition mode is achieved, in general, by employing conditions
which insure that the system does not achieve thermodynamic
equilibrium until at least the nucleation or droplet growth
has been initiated. Process-wise, this can be accomplished
by merely allowing the system to cool without subjecting it
to mixing or other shear forces. The time parameter may also
be significant where relatively thick blocks are being formed,
making more rapid cooling desirable in such instances.
Within the range over which cooling results in the
-31-
l:lZU6~70
formation of a plurality of liquid droplets, there is a general
indication that the rate of cooling may affect the size of the
resulting cells, wit~ increasing rates of cooling resulting in
smaller cells. In this connection, it has been observed that
an increase in the cooling rate from about 8C./rninute will
apparently result in decreasing the cell size in half for a
polypropylene microporous polymer. Accordingly, external cool-
ing may be utilized, if desired, to control the ultimate cell
and pore size, as will be discussed in more detail.
The manner in which the interconnecting passageways
or pores are formed in the cellular structure is not fully
understood. However, and while the applicant does not wish
to be bound by any particular theory there are various possible
mechanisms that serve to explain this phenomenon, each of which
is consistent with the concept described herein. The formation
of the pores may accordingly be due to thermal shrinkage of
the polymer phase upon cooling, the liquid solvent droplets
behaving as incompressible spheres when the solvent has a
smaller expansion coefficient than the polymer. Alternatively,
and as has been pointed out, even after the solvent droplets
have reached their maximum siæe, the polymer-rich phase will
still contain some residual solvent and vice versa. When the
system continues to cool, additional phase separation may ac-
cordingly occur. The residual solvent in the polymer-rich
skin can therefore diffuse to the solvent droplet, reducing
the volume of the polymer-rich skin and increasing the volume
of the solvent droplet. Conceptually, this may weaken the
polymer skin: and the volume increase of the solvent or liquid
phase may result in internal pressure which is capable of
bursting through the polymer skin, connecting adjacent solvent
droplets. Related to this last mechanism, the polymer may
-32-
670
redistribute itself into a more compact state as the residual
liquid migrates out of the polymer skin, as by crystallization
when this type of polymer is employed. In such a situation,
the resulting polymer skin would likely shrink and have im-
perfections or apertures, likely located in the areas of par-
ticular weakness. The weakest areas would, it can be expected,
be located between adjacent liquid droplets, and, in such a
situation, the apertures would form between adjacent liquid
droplets and result in the interconnection of the solvent
droplets. At any rate, and regardless of the mechanism, the
interconnecting pores or passageways inherently result when
the process is carried out as has been described herein.
An alternative explanation of the mechanism by which
the pores are formed is based on the "Marangoni effect", which
has been discussed i~ Marangoni, C, Nuovo Cimento [2], 5-6.239
(1871, [3], 3,97,193 (1878) and Marangoni, C. Ann. Phys. L~z.
(1871), 143,337. me Marangoni effect has been utilized to
explain the phenomenon occurring when alcoholic beverages
spontaneously reflux off the sides of drinking glasses, parti-
cularly,the mechanism occuring when a condensed droplet flowsback into the bulk of the liquid. The fluid of the droplet
first penetrates that of the bulk, followed by the rapid re-
treat of part of the fluid back into the droplet. It has been
hypothesized that a similar physical phenomenon is occurring
with the liquid droplets which have formed as a result of the
liquid-liquid phase separation. Thus, one droplet may encoun-
ter another and the fluid of one may penetrate/that of the
other, followed by rapid separation of the two droplets, per-
haps then leaving a portion of the liquid connecting the two
droplets and forming the basis for the interconnecting pores
of the cellular structure. For a more recent discussion of
-33-
~lZ~6~0
the Marangoni effect, one may refer to Charles & Mason, J.
Colloid Sc:, 15, 236-267 (1960).
If the cooling of the homogeneous solution occurs at
a sufficiently fast rate, liquid-liquid phase separation may
occur under non-equilibrium thermodynamic conditions, but
substantial solidification of the polymer may occur so rapidly
that essentially no nuclea~ion and subsequent growth may
occur. In such an instance there will be no formation of a
plurality of liquid droplets and the resulting microporous
polymer will not have the distinct cellular structure.
mus, under some circumstances it is possible to ob-
tain different microporous structures by use of exceptionally
high cooling rates. For example, when a solution of 75 parts
of N,N-bis(2-hydroxyethyl) tallowamine and 25 parts of poly-
propylene is cooled at rates varying from about 5C to about
1350C per minute, the cellular microstructure results. The
main effect of different cooling rates in the foregoing range
on the composition is the alteration of the absolute cell
size. Where cooling rates of about 2000C/minute are achieved,
the microstructures take on, for example, a fine lacey, non-
cellular appearance~ When a solution of 60 parts of N,N-
bis(2-hydroxyethyl) tallowamine and 40 parts of polypropylene
are treated in the same fashion, cooling rates in excess of
2000C per minute must be achieved before the lacey non-
cellular structure is obtained.
To investigate the effect of cooling system rate on
the cell size of the cellular structure and to investigate
the rate of cooling necessary for transition from production
of the cellular structure to production of a structure having
no distinct cells, various concentration of polypropylene
and N,N-bis(2-hydroxyethyl) tallowamine were prepared as
-34-
~Z~6710
homogeneous solutions. To accomplish such an investigation,
the DSC-2, previously discussed, was utilized in conjunction
with standard X-ray equipment, and a scanning electron micro-
scope. As the DSC-2 is capable of a maximum cooling rate of
about 80C/minute, a thermal gradient bar was also utilized.
me thermal gradient bar was a brass bar which was capable of
having a temperature differential of greater than 2000C
across its one meter length, upon which samples could be
placed.
An infrared camera was utilized to determine the tem-
peratures of the samples by first focusing the camera on a
pan which was placed in the closest of the ten bar sites to
a temperature of 110C, as measured with a thermocouple. m e
camera emissivity control was then adjusted until the camera
temperature readout agreed with the thermocouple reading.
For any given run, the camera was focused on a loca-
tion at which a given pan containing the sample solution was to
cool. me pan with the sample was then placed on the thermal
gradient bar for two minutes. As the pan was removed from
the bar to be placed in the field of the camera, a stopwatch
was started. As soon as the camera indicated that the pan
was at a temperature of 110C, the stopwatch was stopped and
the time recorded. mus, the determined cooling rates were
based on the time needed for the sample to cool over a tem-
perature range of approximately 100C.
It was found that the controlling limitation on the
rate of cooling was not the amount of material being cooled.
It was noted that although heavier samples cooled more slowly
than light ones, the silicon oil which was used on the bottom
of the pan for thermal conductivity between the pan and bar
has significant influence on the rate of cooling. mus the
-35-
~lZ~6~0
highest cooling rates were obtained by placing a pan without
any silicon oil on an ice cube and the slowest cooling rates
were obtained with a pan having a heavy coating of silicon
oil which was placed onto a piece of paper.
Five samples of polypropylene were prepared contain-
ing from 0 percent N,N-bis(2-hydroxyethyl) tallowamine to 80
percent of said amine, for use in investigating the effect of
cooling rate on the resultant structures. Approximately 5
milligrams of each of said samples were heated on the DSC-2
10 inside of sealed pans at 40C per minute to a holding temper-
ature of 175C for the sample containing 20 percent poly-
propylene, 230C for the sample containing 40 percent poly-
propylene, 245C for the sample containing 60 percent poly-
propylene, 265C for the sample containing 80 percent poly-
propylene and 250C for the 100 percent polypropylene.
Each of the samples were heated to and maintained
at the appropriate holding temperature for five minutes
prior to being cooled. After the samples were cooled at the
desired cooling rate, the ~,N-bis(2-hydroxyethyl) tallowamine
20 was extracted from the sample with methanol and the sample an
analyzed. The results of the study are summarized in TABLE I
showing the size-s of the cells in microns, in the resulting
compositions. All cell sizes were determined by making
measurements from the respective scanning electron micro-
graphs.
--3~--
l~'Z0670
TABLE I
Cooling Rate 5C/Min. 20C/Min. 40C/Min. 80C/Min.
Composition
0% Amine None( ) None( ) None(l) None( )
20% Amine 0 5(2) 0 5(2) None( ) None(3)
40% Amine 2.5~ ) 2 o(4) 2.o(4) o 7(5)
60% Amine 4.0 3.0 2.0 1.5(6)
80% Amine 0.5 4,0 3.0 3 o(6)
(1) Some irregular holes present
(2) Approximation of largest cell size
(3) Porosity probably too small to measure
(4) Some small cells present at 1/10 size of larger
cells
(5) Additional cells present too small to measure
(6) Some formation of non-cellular structure
An additional cooling rate study was conducted
utilizing samples of 20 percent polypropylene and 80 percent
N,N-bis(2-hydroxyethyl) tallowamine on the thermal gradient
bar. Five of such samples were cooled at various rates from
a melt temperature of 210C and the results are summarized in
TABLE II, showing the sizes of the cells in microns, the same
procedure being utilized as for obtaining the data for TABLE
I.
TABLE II
Cooling Rate 200C 870C/Min. 1350C/Min. 1700C/Min.
Composition
80% Amine 0.5-3 0.5-1.5 1.5-2.5 Non-cellular
From TABLES I and II it is apparent that for increas-
ing cooling rates, the size of the cells in the resulting com-
positions decrease, in general. Furthermore, with respect tothe polymer/liquid system comprised of 20 percent polypropyl-
l:lZ~670
ene and 80 percent N,~-bis(2-hydroxyethyl) tallowamine, it is
apparent that at a cooling rate between about 1350C per minute
and 1700C per minute a transition is completed in the nature
of the resultant polymer from essentially cellular to non-
cellular. Such a transition in the resultant structure cor-
responds to the fact that the polymer becomes substantially
solidified after liquid-liquid phase separation has been ini-
tiated but prior to the formation of a plurality of liquid
droplets, as previously discussed.
Additionally five samples of 40 percent polypropyl-
ene and 60 percent N,N-bis(2-hydroxyethyl) tallowamine were
prepared and cooled at rates from 690C per minute to over
7000C per minute, from melt temperatures of 235C, in
accordance with the procedure discussed previously. It was
determined that for such a concentration of polypropylene
and said amine, the transition from cellular to non-cellular
occurs at about 2000C per minute.
Finally, to investigate the crystallinity of struc-
tures prepared over a range of cooling rates, three samples
of 20 percent polypropylene and 80 percent ~,~-bis(2-hydroxy-
ethyl) tallowamine were prepared and cooled at rates of 20C,
1900C and 6500C per minute. From the DSC-2 data for such
; samples it was determined that the degree of crystallinity in
the three sample~ was essentially equivalent. mus it appears
that variations in the cooling rate have no significant effect
upon the degree of crystallinity of the resulting structures.
Howe~er, it was determined that as the rate of cooling was
; significantly increased, the crystals which were produced
became less perfect, as expected.
Having formed the homogeneous solution of polymer
and liquid and having cooled the solution in an appropriate
-38-
llZ~670
manner to produce a material having suitable handling strength,
the microporous product may be thereafter formed by removing
the liquid by, for example, extracting with any suitable sol-
vent for the liquid which is, likewise, quite obviously, a
non-solvent for the polymer in the system. The relative mis-
cibility or solubility of the liquid in the solvent being
employed will, in part, determine the effectiveness in terms
of the time required for extraction. Also, if desired, the
extracting or leaching operation can be carried out at an
elevated temperature below the softening point of the polymer
to lessen the time requirements. Illustrative examples of
useful solvents include isopropanol, methylethyl ketone,
tetrahydrofuran, ethanol and heptane.
The time required will vary, depending upon the
liquid employed, the temperature used and the degree of ex-
traction required. More particularly, in some instance, it
may be unnecessary to extract 100% of the liquid used in the
system and minor amounts may be tolerated, the amount which
can be tolerated being dependent upon the requirements of the
intended end-use application. The time required may accord-
ingly vary anywhere in the range of from several minutes or
perhaps less to more than 24 hours or even more, depending
upon many factors, including the sample thickness.
Removal of the liquid can also be achieved by other
known techniques. Illustrative examples of other useful
removal techniques include evaporation, sublimation and dis-
placement.
It should be noted in addition, when using conven-
tional liquid extraction techniques, the cellular microporous
polymer structures of the present invention may exhibit re-
lease of a li~uid contained in the structure in a fashion
-39-
670
which approaches zero order, i.e., the rate of release may
be essentially constant after, perhaps, an initial period at
a high release rate. In other words, the rate of release may
be independent of the amount of the liquid that has been
released thus, the rate at which the liquid is extracted
after, for example, three-fourths of the liquid has been re-
moved from the structure is approximately the same as when
the structure was one-half filled with liquid. An example of
such a system exhibiting an essentially constant release rate
is the extraction of N,~-bis(2-hydroxyethyl) tallowamine from
polypropylene with isopropanol as the extractant. Also, in
any situation, there probably will be an initial induction
period before the rate of release becomes identifiable. When
release of a liquid is allowed to proceed by evaporation, the
rate of release tends to be first order.
When the cooling of the polymer/liquid solution oc-
curs such that the plurality of liquid droplets form as pre-
viously discussed, and the liquid removed therefrom, the
resulting microporous product forms a relatively homogeneous
cellular structure comprising, on the microscale, a series of
substantially spherical, enclosed microcells distributed subs-
tantially uniformly throughout the structure. Adjacent cells
are interconnected by smaller pores or passageways. This
basic structure can be seen from the photomicrographs of Figs.
4 and 5. It should be appreciated that the individual cells
are, in fact, enclosed but appear open in the photomicro-
-- graphs due to the fracturing involved in the sample prepar-
ation for taking the photomicrographs. On a macroscale, at
least for the crystalline polymers, the structure appears to
have planes similar to the fracture planes along the edges of
crystal growth (see Fig. 2) and, as can be seen from Fig. 3,
-40-
670
is coral-like in appearance. The cellular microstructure may
further be analogized to zeolite clay structures, which con-
tain definite "chamber" and "portal" regions. The cells cor-
respond to the larger chamber areas of zeolite structures while
the pores correspond to the portal regions.
In general, in the cellular structure the average
diameter of the cells will vary from about 1/2 micron to about
100 microns, about 1/2 to about 50 microns being more typical
whereas the average diameter of the pores or interconnecting
passageways appears to be typically about a magnitude smaller.
Thus, for example, if the cell diameter in a microporous poly-
mer structure of the present invention is about 1 micron, the
average diameter of the pore or interconnecting passageway
will be about 0.1 micron. As has been pointed out previously,
the cell diameter and also the diameter of the pore or pas-
sageway will be dependent upon the particular polymer-liquid
system involved, the rate of cooling and the relative amounts
of polymer and liquid utilized. However, a broad range of
cell to pore ratios are possible, as,for example, from about
2:1 to about 200:1, typically, from about 5:1 to about 40:1.
As can be seen from the several Figures, it may be
considered that some of the exemplary cellular microporous
polymer products do not possess the unique microcellular
structure which has been described herein. It must, however,
be appreciated that this structure can, in some instances, be
masked by additional modifications resulting from the particu-
lar liquid or polymer involved or the relative amounts em-
ployed. This masking may be in whole or in part, ranging from
small polymer particles attached to the walls of the cells
to gross "foliage-type" polymer build-ups which, in the mi-
crographs, tend to completely mask the basic structure. mus,
-41-
}6~iO
for example, and as can be seen from Figs. 21 and 25, small
polymer balls are adhered to the cell cavities of the struc-
tures. This additional formation can be understood by refer-
ence to the nucleation and growth concept previously described.
Thus, in systems with extremely high solvent or liquid con-
tent, the maximum cavity size will typically be comparatively
large. This likewise means that the time required for the
cavity or droplet to reach its maximum size will similarly
be increased. During this time, it is possible for additional
nuclei to form nearby. Two or more nuclei may then come into
contact with one another prior to each reaching its maximum
size. In such instances, the resulting cellular structure
has less integrity and somewhat less regularity than the
basic structure previously described. Moreover, even after
the liquid droplets have reached maximum size, depending
upon the system involved, the solvent or liquid phase may
still contain some amount of residual polymer or vice
versa. In such situations, as the system continues to cool,
some additional residual phase separation may occur. When
the residual polymer simply separates out of solution,
spheres of polymer can form as shown in Figs. 21 and 25.
On the other hand, if the residual polymer diffuses to the
polymer skin, the walls will appear fuzzy and irregular,
thus providing the "foliage-type" structure. This "foliage-
type" structure may only partially mask the basic structure,
as seen in Figs. 28 and 29 or it may wholly mask the struc-
ture as shown in Fig. 6.
The "foliage-type" structure is also more prone to
occur with certain polymers. Thus, the microporous low den-
sity polyethylene structures, perhaps due to the solubilityor the like of the polyethylene in the particular liquids
-42-
)670
employed, typically provide this sort of structure. This
can be observed from Fig. 14. Further, when the levels of
liquid employed are extremely high, this will also occur with
polymers such as polypropylene which otherwise exhibit the
basic structure. This can be readily observed by contrast-
ing the "foliage-type" structure of the microporous product
of Fig. 6 with the basic structure of Fig. 8 in which the
polymer content is 40% by weight comparison to the 10% poly-
propylene in the structure illustrated in Fig. 6.
For most applications, it is preferred to utilize
a system which results in the formation of the basic cellular
structure. The relative homogeneity and regularity of this
structure provides predictable results, such as are required
in filtration applications. However, the foliage-type struc-
ture may be more desirable where relatively high surface area
structures are desired such as in ion exchange or various ad-
sorptive processes.
As can be likewise observed, some of the structures
have small holes or apertures in the walls of the cells. This
phenomenon can also be understood by reference to the nuclea-
tion and growth concept. Thus, in a section of the system
in which a few spatially associated liquid droplets have al-
ready reached their maximum size, each droplet will be enclosed
by a polymer-rich skin. However, in some instances, some
solvent may be trapped between the enclosed droplets but
cannot continue its migration to the larger droplets due to
impenetrability of the skins. Accordingly, in such instances,
a nucleus of the liquid may form and grow, resulting in small
cavity embedded adjacent to the larger droplets. After ex-
traction of the liquid, the smaller droplets will appear asa small hole or aperture. This can be observed in the micro-
-43-
llZ~670
porous structures shown in Figs. 11-12 and 20.
Another interesting characteristic of the cellular
structures of the present invention relates to the surface
area of such structures.
The theoretical surface area of the cellular micro-
porous structure consisting of interconnected spherical cavi-
ties of about 5 microns in diameter is approximately 2-4 sq
meters/gm. It has been found that microporous polymers pro-
duced by the instant invention need not be limited to the
lQ theoretical limit of surface area. Determination of surface
area by the B.E.T. method described in Brunauer, S., Emmet,
P.H., and Teller, E. "The Adsorption of Gases in Multimolecu-
lar Layers" J. Am. Chem. Soc., 60,, 309,-16 (1938), has shown
surface areas far in excess of the theoretical model which is
not related to the void space, as shown in TABLE III, for
microporous polymers made from polypropylene and ~,N-bis(2-
hydroxyethyl) tallowamine.
TABLE III
/0 VOID SPECIFIC SURFACE AREA
2089.7 96.2 m2/gm
72.7 95.5
60.1 98.0
50.5 99.8
28.9 88.5
Surface area may be reduced by careful annealing ofthe microporous polymer without affecting the basic structure.
Microporous polypropylene prepared at 75% void space using
N,N-bis(2-hydroxyethyl) tallowamine as the liquid component
was extracted and dried at temperatures not exceeding room
temperature and subsequently heated to affect the surface
-44-
llZ~6710
area. The initial surface area was 96.9 m /gm. After eleven
40 minute heat periods at 62C, the surface area fell to 66
m2/gm. Further heating at 60C for an additional 66 hours
decreased the surface area to 5104 m2/gm. Treatment of ano-
ther sample at 90C for 52 hours decreased the surface area
from 96.9 to 33.7 m2/gm. me microporous structure was not
significantly changed when examined by scanning electron mi-
croscopy. mese results are summarized in Table IV.
TABLE IV
TreatmentSurface area (m /gm) % Change
none 96.9
eleven, 40 min.
treatments at 62C 66.0 32%
Above plus 66 hours
at 60C 51.4 47%
52 hours at 90C 33.7 65%
It should be quite apparent that one of the unique
features of the cellular structures of the present invention
relates to the ~xistence of both distinct, substantially
spherical, enclosed microcells which are uniformly distributed
throughout the structure and distinct pores which interconnect
said cells, said pores being of a smaller diameter than said
cells. Furthermore, said cells and interconnecting pores
have essentially no spatial orientation, and may be classified
as being isotropic. mus there is no preferred direction, as
for example, for flow of a liquid through the structure. This
is-in marked contrast to prior art materials which do not
exhibit such a cellular structure. Many prior art systems
have a non-descript structure which lacks any structural con-
figuration capable of definition. It is therefore quitesurprising that a microporous structure can be made having
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llZU670
such a degree of uniformity, which may be especially desirable
for many applications needing highly uniform materials.
The cellular structure may be defined in terms of
the ratio of the average diameter of the cells ("C") to the
diameter of the pores ("P"). Thus, the C/P ratio as previous-
ly discussed may vary from about 2 to about 200, about 5 to
about 100 being typical and about 5 to about 40 being even
more typical. Such a C/P ratio distinguishes the cellular
structure of the present invention from any previous prior art
microporous polymeric product. As there is no known prior art
synthetic thermoplastic polymeric structure having distinct
cells and pores, all such prior art materials must be consi-
dered to have a cell to pore ratio of 1.
Another means of characterizing the cellular struc-
tures of the present invention is by a sharpness Factor, "S".
m e S factor is determined by analyzing a mercury intrusion
curve for the given structure. All mercury intrusion data
discussed in this application was determined by use of a
Micrsmeritics Mercury Penetration Porosimeter, Model 910
series. The S value is defined as the ratio of the pressure
at which 85 percent of the mercury penetrated to the pressure
at which 15 percent of the mercury penetrated. mis ratio is
a direct indication of the variation in pore diameter across
the central 70 percent of the pores in any given sample, as
pore diameter is equal to 176.8 divided by the pressure in
p.s.i.
The S value, then, is a ratio of the diameter of
the pores at which 15 percent of the mercury has intruded to
the diameter of the pores at which 85 percent of the mercury
has intruded. me range for 1 to 15 percent and 85 to 100
percent of mercury intrusion is ignored in determining the S
-46-
6~0
factor. me range from 0 to 15 percent is ignored as pene-
tration in this range may be due to cracks introduced into the
material as a result of the freeze-fracturing to which the
material was subjected prior to performing the mercury in-
trusion study. Also, the range from 85 to 100 percent is
ignored as data in such a range may be due to compression of
the sample rather than to actual penetration of the mercury
into the pores.
Characteristic of the narrow range of pore size
exhibited by the composition of the present invention, the
usual S value for such structures is in the range of from
about 1 to about 30, about 2 to about 20 being typical and
about 2 to about 10 being more typical.
me average size of the cells in the structure range
from about 0.5 to about 100 microns, from about 1 to about 30
microns being typical, from about 1 to about 20 microns being
more typical. As indicated the cell size may vary depending
on the particular resin and compatible liquid utilized, the
ratio of polymer to liquid, and the cooling rate employed to
form the particular microporous polymer. me same variable
will also have an effect upon the average size of the pores in
the resulting structure, which usually varies from about 0.05
to about 10 microns from about 0.1 to about 5 microns being
typical, and from about 0.1 to about 1.0 micron being more
typical. All references to a cell and/or pore size through-
out this application, relate to the average diameter of such
cell or pore, in microns, unless otherwise stated.
By determining the foregoing factors, cell size,
pore size, and S, for the cellular microporous polymers of
the present invention, one may concisely define the cellular
microporous polymers of the present invention. A particularly
-47-
11'~(~670
useful means of so defining the polymers in terms of the log
of the cell to pore ratio ("log C/P") and the log of the ratio
of the sharpness function S to the cell size ("log S/C").
Accordingly, the cellular microporous polymers of the present
invention have a log C/P of from about 0.2 to about 2.4 and
a log S/C of from about - 1.4 to about 1.0, more usually, said
polymers have a log C/P of from about 0.6 to about 2.2 and a
log S/C of from about - 0.6 to about 0.4.
The non-cellular structure of the present invention
which results from the cooling of the homogeneous solution at
such a rate that the polymer substantially solidifies prior to
the formation of the plurality of liquid droplets, may be cha-
racterized primarily with respect to the narrow pore size dis-
tribution of the material in conjunction with the actual pore
size and the spatial uniformity of the structure.
Particularly, the non-cellular microporous polymers
may be characterized by a sharpness function, S, as previously
described with respect to the cellular structures. The S
values exhibited by the non-cellular structure range from about
1 to about 30, about 1 to about 10 being preferred and about 6
to about 9 being more preferred. H~wever, when the pore size
of the material ranges from about 0.2 to about 5 microns, the
S value will range from about 5 to about 10 and will typically
range from about 5 to about 10.~ Such S values for olefinic and
oxidation polymers having microporosity of such a size has been
unknown heretofore, except in the case of highly oriented, thin
films made by a stretching technique. As previously indicated,
the porous polymers of the present invention are substantially
isotropic. Thus a cross-section of the polymers taken along
any spatial plane will reveal essentially the same structural
features.
-48-
}670
The pore sizes of the non-cellular structures of
the present invention are usually in the range from about 0.05
to about 5 microns, from about 0.1 to about 5 microns being
typical, and from about 0.2 to 1.0 micron being more typical.
It is apparent that a surprising feature of the pre-
sent invention is the ability to produce isotropic microporous
structures from olefinic and oxidation polymers, with the
structures having porosity in the range from about 0.2 to
about 5 microns and a sharpness value from about 1 to about
10. It is especially surprising that such structures may be
made in the form, not only of thin films, but also in the form
of blocks and intricate shapes.
When forming a film or block by pouring onto a
substrate such as metal plate, for example, the surface of the
microporous polymer structure of the present invention which
is in contact with the plate will comprise a surface skin that
is non-cellular. The other surface, in contrast, is typically
predominantly open. me thickness of the skin will vary some-
what in accordance with the particular system as well as the
particular process parameters employed. ~owever, typically,
the thickness of the skin is approximately equal to the thick-
ness of a single cell wall. Depending upon the particular
conditions, the skin may range from one which is wholly im-
pervious to the passage of liquids to one exhibiting some
degree of liquid porosity.
If a solely cellular structure is desired for the
ultimate application, the surface skin may be removed by any
of several techniques. Ac illustrative examples, the skin
could be removed by employing any one of several mechanical
means such as abrading, puncturing the skin with needles or
fracturing the skin by passing the film or other structure
-49-
liZ(~670
through differential speed rollers. Alternatively, the skin
could be removed by microtoming. The skin may also be removed
by chemical means, i.e. - by brief contact with a suitable sol-
vent for the polymer.
For example, when a solution of polypropylene in
N,N-bis(2-hydroxyethyl) tallowamine i5 continuously extruded
as a thin film onto an endless stainless steel belt conveyor,
application of a small amount of liquid solvent upon the belt
immediately prior to the solution application zone will ef-
fectively remove the surface formed at the solution-steel in-
terface. Useful liquids are materials such as isoparaffinic
hydrocarbons, decane, decalin, xylene and mixtures such as
xylene-isopropanol and decalin-isopropanol.
However, for some end use applications, the presence
of the skin will not only not be a detriment but will be a
necessary component. For example, as is known, ultrafiltration
or other membrane-type applications utilize a thin, liquid im-
penetrable film. Accordingly, in such applications, the micro-
porous portion of the structure of the present invention would
have particular utility as a support for the surface skin
which would be functioning membrane in such applications.
Wholly cellular structures can also be directly prepared by
various techniques. mus, for example, the polymer-liquid
system could be extruded into air or a liquid medium such as,
for example, hexane.
me microporous polymer structures of the present
invention, as has been previously discussed, have cell and
pore diameters with extremely narrow size distributions which
are indicative of the unique structures and their relative
homogeneity. The narrow size distribution of the pore dia-
meters is apparent from mercury intrusion data, as can be seen
-50-
67~
from Figs. 30-33. The same general distribution is obtained
regardless of whether the structure is in the form of a film
(Figs. 30-32) or a block (Fig. 33). The characteristic pore
size distribution of the microporous structure of the present
invention is in marked contrast to the sign ficantly broader
pore size distributions of prior microporous polymer products
achieved by prior processes, such as, for example, those set
forth in U.S. patents 3,310,505 and 3,378,507, as will be
discussed in greater detail in connection with the Examples.
For any of the microporous polymers made in accord-
ance with the present invention, the particular end use appli-
cation will typically determine the amount of void space and
pore size requirements. For example, for prefilter applica-
tions, the pore size will typically be above 0.5 microns while,
in ultrafiltration, the pore sizes should be less than about
0.1 micron.
In applications where the microporous structure
serves, in effect, as a receptacle for a functionally useful
liquid strength considerations dictate the amount of void space
where controlled release of the contained functional liquid is
involved. Similarly, in such cases, the pore size will be dic-
tated by the rate of release desired, smaller pore sizes tend-
ing to provide slower rates of release.
Where the microporous structure is to be utilized
to convert a liquid polymer additive such as a flame retard-
ant to a solid, some minimum strength is generally desired;
but, consistent with this minimum, it will typically be desired
to utilize as much liquid as possible since the polymer serves
merely as a receptacle or carrier.
From the foregoing discussions it should be appre-
ciated that in accordance with one aspect of the present in-
-51-
llza67lD
vention, microporous products containing a functionally use-
ful liquid such as polymer additive (e.g. - flame retardant)
may be prepared which behave,as, and may be processed as, a
solid. To this end, the resulting microporous polymer may be
reloaded with the desired functional liquid. This can be ac-
complished by conventional absorption techniques, and the
amount of liquid taken up will be essentially the same as the
amount of liquid used in forming the microporous polymer in
the first instance. Any useful organic liquid may be employed
so long as, of course, the liquid is not a solvent for the
polymer, or otherwise attacks or degrades, the polymer at the
working temperature. me microporous products containing the
functionally useful liquid may be formed from or by using
microporous polymers having either the cellular or non-cellu-
lar structure, as the matrix in which the liquid is incor-
porated.
Similarly, such microporous products can be prepared
by a displacement technique. In accordance w~th this embodi-
ment, the microporous polymer intermediate is first prepared,
and the liquid is then displaced, whether with the desired
functionally useful liquid or with an intermediate displacing
liquid. In either case, rather than extracting the liquid
used in forming the microporous polymer intermediate, the
displacement is carried out by conventional pressure or va-
cuum displacement or infusion techniques. Any functional or
intermediate displacing liquid may be used which could be
used as an extracting liquid to form the microporous polymer,
i.e. - is a non-solvent for the polymer yet has some solu-
bility or miscibility with the liquid being displaced. As
is apparent, minor amounts of the displaced liquid or liquids
may remain following displacement. The requirement of the
-52-
112(~6~'0
end use will typically dictate the extent of the displacement
desired, thus, amounts of about 1 to about 10% by weight may
be tolerated in some applications. If required, multiple dis-
placements and/or using liquids that can be readily removed
by evaporation allows removal of essentially all of the liquid
or liquids being displaced, i.e. - less than about 0.03 or so
weight per cent of residual liquid can be achieved. From the
economic standpoint, it will generally be desirable to utilize
a displacing liquid which has a boiling point sufficiently
different from the liquid being displaced to allow recovery and
reuse. For this reason, it may be desirable to utilize an
intermediate displacing liquid.
As may also be apparent from the foregoing examples
of useful polymer-liquid systems, a further method of prepar-
- ing a polymer-functionally useful liquid material involves
utilizing the microporous polymer intermediate without fur-
ther processing since numerous functionally useful liquids
have been found to be operable as the compatible liquid with
particular polymers to form the solid microporous polymer
intermediate. Thus, intermediates which behave as solids
can be directly made with liquids useful as lubricants,
surfactants, slip agents, moth repellents, pesticides, plas-
ticizers, medicinals, fuel additives, polishing agents, sta-
bilizers, insect and animal repellents, fragrances, flame
retardants, antioxidants, odor masking agents, antifogging
agents, perfumes and the like. For example, with low den-
sity polyethylene,useful intermediates containing a lubricant
or a plasticizer may be provided by employing either an ali-
phatic or aromatic ester having eight or more carbon atoms
or a nonaromatic hydrocarbon having nine or more carbon atoms.
Useful products containing a surfactant and/or wetting agent
-53-
67~D
may be formed with low density polyethylene by using a poly-
ethoxylated aliphatic amine having eight or more carbon atoms
or a nonionic surfactant. With polypropylene, surfactant -
containing intermediates can be provided by utilizing di-
ethoxylated aliphatic amines having eight or more carbon atoms.
Polypropylene intermediates containing slip agents may be
prepared by using a phenylmethyl polysiloxane while low density
polyethylene slip agent intermediates are formed by employ-
ing an aliphatic amide having twelve to twenty-two carbon
atoms. Low density polyethylene fuel additive intermediates
may be prepared by utilizing an aliphatic amine having eight
or more carbon atoms or an aliphatic dimethyl tertiary amine
having twelve or more carbon atoms. The tertiary amines may
also form useful additive intermediates with methylpentene
polymers. High and low density polyethylene intermèdiates
containing a stabilizer can be formed by using an alkyl aryl
phosphite.
Intermediates of low density polyethylene including
an antifogging agent may be provided by utilizing the glycerol
mono or diester of a long chain fatty acid having at least
ten carbon atoms. Intermediates having flame retardants in-
corporated therein may be prepared with high and low density
polyethylene, polypropylene, and a polyphenylene oxide -
polystyrene blend by using a polyhalogenated aromatic hydro-
carbon having at least four halogen atoms per molecule. Use-
ful materials should, of course, be liquid at the phase sepa-
ration temperature as described herein. Other systems which
have been found useful will be identified in connection with
the Examples presented hereinafter.
Furthermore, for polypropylene, high density poly-
ethylene and low density polyethylene, certain classes of
-54-
llZ~670
ketones which have been found to be especially useful as
animal repellants may be employed generally in the practice
of the present invention. Such ketones may include saturated
aliphatic ketones having from 7 to 19 carbon atoms, unsatura-
ted aliphatic ketones having from 7 to 13 carbon atoms, 4-t-
amyl cyclohexanone, and 4-t-butyl cyclohexanone.
me following Examples are presented to more fully
explain the present invention and are merely illustrative of
the present invention and are not intended as a limitation
upon the scope thereof. Unless otherwise indicated, all
parts and percentages are by weight.
me porous polymer intermediates and the micropo-
rous polymers described in the Examples presented hereinafter
were prepared according to the following procedure:
A. Porous Polymer Intermediates:
The porous polymer intermediates are formed by ad-
mixing a polymer and a compatible liquid, heating the mix-
ture to a temperature which is usually near or above the
softening temperature of the resin such that homogeneous
solution is formed, and then cooling the solution without
subjecting it to mixing or other shear forces to ~orm a
macroscopically solid homogeneous mass. When solid blocks
of the intermediates are to be formed, the homogeneous solu-
tion is allowed to assume a desired shape by pouring it into
an appropriate receptacle, which is usually made of metal or
glass, and the solution allowed to cool under ambient room
conditions, unless otherwise noted. me rate of cooling under
room temperature conditions will vary, depending on items such
as sample thickness and composition, but will usually be in
the range of from about 10 to about 20C per minute. me
receptacle is typically cylindrical in shape with a diameter
-55-
9 ~Z~670
of from about 0.75 to about 2.5 inches and the solution is
typically poured to a depth of from about 0.25 to about 2.0
inches. When films of the intermediates are formed, the
homogeneous solution is poured onto a metal plate w~ich is
heated to a temperature sufficient to allow the drawing of the
solution into a thin film. The metal plate is then placed
into contact with a dry ice bath to rapidly cool the film
below its solidification temperature.
B. Porous Polymer:
me microporous polymer is formed by extracting the
compatible liquid used to form the porous polymer intermediate,
typically by repetitively washing the intermediates in a sol-
vent such as isopropanol or methylethyl ketone, then drying
the solid microporous mass.
EXAMPLES
The following examples and tables illustrate some
of the various polymer/compatible liquid combinations which
are useful in forming the porous polymer intermediates of
this invention and various prior art or commercially available
microporous products. Solid blocks of the intermediates were
formed for all of the exemplified combinations and, when so
indicated in a table, thin films of the intermediate were
also formed, using the procedure described above. As indi-
cated in the following tables, many of the intermediate com-
positions were used to form the microporous polymers of this
invention, by using a suitable solvent to extract the compa-
tible liquid from the intermediate composition, and subse-
quently removing said solvent, as by evaporation.
Many of the compatible liquids which are illus-
trated in the following examples are, as indicated in thetables, functional liquids which are useful not only as
-56-
11;~C~6~0
compatible liquids but also as flame retardants, slip agents,
and the like. Ihus, the intermediate compositions which are
formed with such functional liquids are useful as solid poly-
mer additives and the like, as well as intermediates in the
formation of porous polymers. me functional liquids which
appear in the following examples are indicated to be such by
the presence of one or more of the following symbols under
column "Type of Functional Liquid": AF (Antifogging Agent),
AO (Antioxidant); AR (Animal Repellant), FA (Fuel Additive),
FG ~ragrance), FR (Flame Retardant), IR (Insect Repellant),
L (Lubricant), M (Medicinal), MR (Moth Repellant), OM (Odor
Masking Agent), P (Plasticizer), PA (Polishing Agent),
PE (Pesticide) PF (Perfume), S (Slip Agent), SF (Surfactant),
and ST (Stabilizer).
- EXAMPLES 1 to 27
Examples 1 through 27 in Table V illustrate the form-
ation of homogeneous porous polymer intermediates, in the
form of cylindrical blocks having a radius of about 1.25
inches and a depth of about 2 inches, from high density poly-
ethylene t"HDPE") and the compatible liquids found to be use-
ful, using the standard preparation procedure. The high den-
sity polyethylene was supplied by Allied Chemical under the
designation Plaskon * AA 55-003, having a melt index of 0.3g/
10 minutes and a density of 0.954g/cc. Many of the exempli-
fied intermediates were extracted to form porous polymers, as
indlcated in the Table.
The details of preparation and the type of
functionally useful liquid noted are set forth in Table V:
* Trade Mark
670
TABLE V
~IDPE
Type of
Functional
Ex. No. Liquid Type and Liquid ~/~ Liq. C. Liquid
Saturated Aliphatic Acids
1 decanoic acid* 75 230
Primary Saturated Alcohols
2 decyl alcohol* 75 220 PF
3 l-dodecanol* 75 220 ---
Secondary Alcohols
4 2-undecanol* 75 220 ---
6-undeconal* 75 230 ---
Aromatic Amines
6 N,N diethylaniline* 75 230 ---
Diesters
7 dibutyl sebacate* 70 220 L, P
8 dihexyl sebacate* 70 220 L, P
Ethers
9 diphenyl ether 75 220 PF
benzyl ether* 70 220 PF
Haloqenated
11 hexabromobenzene 70 250 FR
12 hexabromobiphenyl 75 200 FR
13 hexabromocyclodecane 70 250 FR
14 hexachlorocyclopentadiene 70 200 FR
octabromobiphenyl 70 280 FR
Terminally Double Bonded
Hydrocarbons
16 l-hexadecene* 75 220 ---
* The liquid was extracted from the solid.
-58-
11~0670
TABLE V (continued)
HDPE Type of
Functional
EX. No. Liquid Type and Liquid /O Liq. C. Liquid
Aromatic Hydrocarbons
17 diphenylmethane* 75 220 OM
18 naphthalene* 70 230 MR
Aromatic Ketones
19 acetophenone 75 200 PF
Aromatic Esters
butyl benzoate* 75 200 L, P
Miscellaneous
21 N,N-bis(2-hydroxyethyl)
tallowamine (1) * 70 250 ---
22 dodecylamine* 75 220 ---
23 N-hydrogenated tallow-
diethanol amine 50 240 SF
2~ Firemaster BP-6 (2) 75 200 ---
Phosclere P315C* (3) 75 220 ST
26 Quinoline 70 240 M
27 dicocoamine (4) 75 220 ---
* The liquid was extracted from the solid.
(1) A permanent internal antistatic agent having the following
properties was used: Boiling Point 1 mm Hg, C., 215-220,
Specific Gravity 90F., 0.896, Viscosity, SSU, 90F., 476.
(2) Michigan Chemical Corporation's trademark for its hexa-
bromobiphenyl, a flame retardant having the following
properties was used: Softening Point, C., 72, Density,
25C, g/ml, 2.57, Viscosity, cps, 260-360 (Brookfield
No. 3 spindle at 110C.).
-59-
llZ~670
TABLE VI
LDPE
Type of
Functional
Ex. ~o.(l) Liquid Type and Liquid % Liq. C. Liquid
Aliphatic Saturated Acids
28 caprylic acid* 70 210 ---
29 decanoic acid* 70 190 ---
hexanoic acid* 70 190 ---
31 lauric acid* 70 220 ---
32 myristic acid* 70 189 ---
33 palmitic acid* 70 186 ---
34 stearic acid* 70 222 ---
undecanoic acid* 70 203 ---
Unsaturated Aliphatic Acids
36 erucic acid (2)* 70 219 ---
37 oleic acid* 70 214 PA
Aromatic Acids
38 phenyl stearic acid* 70 214 ---
39 xylyl behenic acid* 70 180 ---
M~scellaneous Acids
Acintol FA2(Tall Oil Acids)(3)* 70 204 ---
* The liquid was extracted from the solid.
(1) Union Carbide Company's Bakelite** polyethylene having the
following properties was used: Density, g/cm3, 0.922; Melt
Index, g/10 min., 21.
(2) This is an acid with a density of 0.8602 g/cc and a melting
point of 33-34C.
(3) Arizona Chemical Company's trademark for a mixture of fatty
acids. The composition and physical properties are: Fatty
Acid Composition (98.2% of total); Linoleic, ~on-conjugated,
%, 6; Oleic, %, 47, Saturated, %, 3; Other Fatty acids, %,
8; Specific Gravity, 25/25~C., 0.898; Viscosity, SSU,
100F., 94.
** Trademark
-60-
670
~.,
TABLE VI (continued) .
LDPE Type of -
Functional
Ex. ~o. Liquid Type and Liquid % Liq. C. Liquid
Miscellaneous Acids (continued) .
41 olefin acid L-6* 70 206 --- .
42 olefin acid L-9* 70 186 ---
43 olefin acid L-ll* 70 203 ---
44 Rosin acid* 70 262 ---
tolylstearic acid 70 183 ---
Primary Saturated Alcohols ~
46 cetyl alcohol* 70 176 --- :
47 decyl alcohol* 70 220 PF :
48 l-dodecanol* 75 200 ---
49 l-heptadecanol* 70 168 --- .
- 50 nonyl alcohol* 70 174 PF
51 l-octanol* 70 178 ---
52 oleyl alcohol* 70 206 FA
53 tridecyl alcohol 70 240 ---
54 l-undecanol* 70 184 -~-
undecylenyl alcohol* 70 199 ---
Secondary Alcohols
56 dinonyl carbinol* 70 201 PF
57 diundecyl carbinol 70 226 ---
58 2-octanol 70 174
59 2-undecanol* 70 205 --- ~:
Aromatic Alcohols
l-phenylethanol* 70 184 PF
61 l-phenyl-l-pentanol 70 196 ---
62 phenyl stearyl alcohol* 70 206 ---
63 nonyl phenol* 70 220 SF, PE
-
* The liquid was extracted from the solid.
-61-
l~Z0670
TABLE VI (continued)
LDPE Type of
Functional
Ex. ~o. Liquid Type and Liquid /O Liq. C. Liquid
Cyclic Alcohols
64 4-t-butyl cyclohexanol* 70 190 PE
menthol* 70 206 PF
Other -OH Containin~ Compounds
66 Neodol-25 (1)* 70 180 ---
67 polyoxyethylene ether of
oleyl alcohol (2) 70 268 SF
68 polypropylene glycol-425* (3) 70 --- SF
Aldehydes
69 salicylaldehyde* 70 188 PF
Primary Amin_s
dimethyldodecylamine 70 200 FA
71 hexadecylamine* 70 207 FA
72 octylamine* 70 172 FA
73 tetradecylamine* 70 186 FA
Secondary Amines
74 bis(l-ethyl-3-methyl pentyl)
amine* 70 190 ---
:
* ~he liquid was extracted from the solid.
(1) Shell Chemical Company's trademark for its synthetic fatty
alcohol of 12-15 carbon atoms.
(2) Croda, Inc.'s, Volpo 3 surfactant having the following
properties was used: Acid Value, max., 2.0, Haze Pt., 1%
aq. soln., insoluble, HLB value, calculated, 6.6, Iodine
Value, Wijs, 57-62 pH of 3% aq. soln., 6-7, hydroxyl
value, 135-150.
(3) Union Carbide Company's trademark for its glycol having the
following properties: Apparent Specific Gravity, 20/20 C.,
1.009, Avg. hydroxyl number, mg. KOH/g, 265, Acid ~umber,
mg KOH per g sample, max., 0.2, pH at 25C. in 10:6 iso-
propanol water soln., 4.5-6.5.
-~2-
6710
TABLE VI (continued)
LDPE Type of
Functional
EX. No. Liquid Type and Liquid /O Liq. C. Liquid
Tertiary Amines
N,N-dimethylsoya-amine* (1) 70 198 FA
76 N,~-dimethyltallowamine* (2) 70 209 FA
Ethoxvlated Amines
77 N-stearyl diethanol amine 75 210 SF, AF
Aromatic Amines
78 aminodiphenylmethane 70 236 ---
79 N-sec-butylaniline 70 196 ---
N,N-diethylaniline* 70 --- ---
81 N,N-dimethylaniline* 70 169 ---
82 diphenylamine 70 186 A0, PE
- 83 dodecylaniline* 70 204 ---
84 phenylstearyl amine* 70 205 ---
N-ethyl-o-toluidine* 70 182 ---
86 p-toluidine* 70 184 ---
Diamines
87 1,8-diamino-p-menthane 70 188 ---
88 N-erucyl-1,3-propane* diamine 70 220 ---
Miscellaneous Amines
branched tetramine L-PS (3) 70 242 ---
cyclododecylamine* 70 159 ---
* The liquid was extracted from the solid.
(1) A tertiary amine having the following properties was used:
Cloud point, F., ASTM 100, Specific Gravity, 25/4C.,
0.813; Viscosity, SSU, at 25C., 59.3.
30 (2) A tertiary amine having the following properties was used:
Melting Range, F., 28 to 41, Cloud Point, F., 60, Speci-
fic Gravity, 25/4C., 0.803, Viscosity, SSU, 25C., 47.
(3) N-phenylstearo -1, 5, 9, 13 azatridecane.
-63-
l~Z~670
TABLE VI (continued)
LDPE Type of
Functional
Ex. No. Liquid Type and Liquid /O Liq. C. Liquid
Amides
91 cocoamide* (1) 70 245 ---
92 N,N-diethyltoluamide 70 262 IR
93 erucamide* (2) 70 250 L, P
94 hydrogenated tallowamide* 70 250 L, P
octadecylamide (3) 70 260 L, P
96 N-trimethylolpropane
stearamide 70 255 L, P
Aliphatic Saturated Esters
97 ethyl laurate* 70 175 ---
98 ethyl palmitate* 70 171 ---
99 isobutyl stearate* 70 194 L
100 isopropyl myristate* 70 192 ---
101 isopropyl palmitate* 70 285 ---
102 methyl caprylate 70 182 ---
103 methyl stearate* 70 195 ---
104 tridecyl stearate 70 202 L
Aliphatic Unsaturated Esters
105 butyloleate* 70 196 L
106 butylundecylenate* 70 205 ---
107 stearylacrylate* 70 205 ~--
* The liquid was extracted from the solid.
(1) An aliphatic amide having the following properties was used:
Appearance, Flake.; Flash Point, C., Approx., 174; Fire
Point, C., Approx., 1~5.
(2) An amide having the following properties was used: Specific
Gravity, .88; Melting Pt., C., 99-109, Flash Pt., C.,
225,
(3) Octadecylamide having the following properties was used:
Appearance, Flake; Flash Point, C., Approx., 225, Fire
Point, C., Approx., 250.
-64-
llZ0670
TABLE VI (continued)
LDPE Type of
Functional
Ex. No. Liquid Type and Liquid /O Liq. C. Liquid
Alkoxy Esters
108 butoxyethyl oleate* 70 200 ---
109 butoxyethyl stearate* 70 205 ---
Aromatic Esters
110 benzylacetate 70 198 -~-
111 benzylbenzoate* 70 242 L, P
112 butylbenzoate* 70 178 L, P
113 ethylbenzoate* 70 200 L, P
114 isobutylphenylstearate* 70 178 L, P
115 methylbenzoate* 70 170 L, P
116 methylsalicylate* 70 200 L, P, PF
117 phenyllaurate* 70 205 L, P
118 phenylsalicylate 70 211 L, P, M, F
119 tridecylphenylstearate* 70 215 L, P
120 vinylphenylstearate* 70 225 L, P
Diesters
121 dibutylphthalate* 70 290 L, P
122 dibutyl sebacate* 70 238 L, P
123 dicapryl adipate 70 204 L, P
124 dicapryl phthalate 70 204 ---
125 dicapryl sebacate 70 206 L, P
126 diethylphthalate* 70 280 IR
127 dihexylsebacate 70 226 --~
128 dimethylphenylene distearate * 70 208 ---
129 dioctyl maleate 70 220 ---
130 di-iso-octyl phthalate 70 212 ---
131 di-iso-octyl sebacate 70 238 ---
* The liquid was extracted from the solid.
-65-
~(16~0
TABLE VI (continued)
LDPE
Type of
Functional
Ex. No. Liquid Type and Liquid % Liq. C. Liquid
Esters-Polyethylene Glycol
132 PEG 400 diphenylstearate 70 326 ---
Polyhydroxylic Esters
133 castor oil 70 270 ---
134 glycerol dioleate * (1) 70 230 AF
135 glycerol distearate * (2~ 70 201 AF
136 glycerol monooleate * (3) 70 232 AF
137 glycerol monophenylstearate 70 268 ---
138 glycerol monostearate * (4) 70 211 AF
139 trimethylolpropane mono-
phenylstearate 70 260 ---
Ethers
140 dibenzylether* 70 189 PF
141 diphenylether* 75 200 ---
* The liquid was extracted from the solid.
(1) A glycerol ester having the following properties was used,
Flash Point, COC, F., 520, Freezing Point, C., 0, Visco-
sity at 25C., cp, 90, Specific Gravity 25/20C., 0.923-
0.929.
(2) A solid with a melting point of 29.1C.
(3) A glycerol ester having the following properties was used
Specific Gravity, 0.94-0.953; Flash Point, COC, F., 435,
Freezing Point, C., 20, Viscosity at 25C., cp, 204.
(4) A glycerol ester having the following pro~erties was used,
Form at 25C., Flakes, Flash Point, COC, F., 410, Melting
Point, C., 56.5-58.5.
-66-
11~0671~
TABLE VI (continued)
LDPE
Type of
Functional
Ex. ~o. Liquid Type and Liquid /O Liq. C. Liquid
Haloqenated Ethers
142 4-bromodiphenylether* 70 180 FR
143 FR 300 BA (1) 70 314 FR
144 hexachlorocyclopentadiene* 70 196 PE, FR
145 octabromobiphenyl* 70 290 FR
Terminal Double Bond ~ydrocarbon
146 l-nonene* 70 174 L
Internal Double Bond HYdrocarbon
147 3-eicosene* 70 204 ---
148 2-heptadecene* 70 222 ---
149 2-nonadecene* 70 214 ---
150 9-nonadecene* 70 199 ---
151 2-nonene* 70 144 L
152 2-undecene 70 196 ---
Aromatic Hydrocarbons
153 diphenylmethane 75 200 PF
154 trans-stilbene* 70 218 ---
155 triphenylmethane 70 225 __A
Aliphatic Ketones
156 dinonylketone* 70 206 ---
157 distearylketone* 70 238 ---
158 2-heptadecanone 70 205 ---
* The liquid was extracted from the solid.
(1) DOw Chemical Company's trademark for its decabromodiphenyl
oxide fire retardant having the following properties was
used: Bromine, %, 81-83, Melting Point, min. 285C., Decom-
position Temp., DTA, 425C.
~1~06710
TABLE VI (continued)
LDPE
Type of
Functional
EX. No. Liquid Type and Liquid % Liq. ~C. Liquid
Aliphatic Ketones (continued)
lS9 8-heptadecanone* 70 183 ----
160 2-heptanone* 70 152 ---
161 methylheptadecylketone* 70 225 ---
162 methylnonyl ketone* 70 170 AR
163 methylpentadecyl ketone* 70 210 AR
164 methylundecyl ketone70 205 ---
165 2-nonadecanone 70 214 ---
166 10-nonadecanone 70 194 ---
167 8-pentadecanone* 70 178 ---
168 ll-pentadecanone* 70 262 ---
169 2-tridecanone* 70 168 ---
170 6-tridecanone* 70 205 ---
171 6-undecanone* 70 188 ---
Aromatic Ketones
172 acetophenone* 70 190 PF
173 benzophenone 70 245 PF
Miscellaneous Ketones
174 9-xanthone* 70 220 PE
Phosphorous Compounds
175 trixylenyl phosphate*70 304 FR
Miscellaneous
176 N,N-bis(2-hydroxyethyl)
tallowamine - 70 210 ---
177 bath oil fragrance No. 5864K 70 183 FG
* me liquid was extracted from the solid.
-68-
11~0671U
TABLE VI (continued)
LDPE
Type of
Functional
Ex. No. Liquid Type and Liquid /O Liq. C. Liquid
Miscellaneous (continued)
178 EC-53 Styrenated nonyl
phenol (l)* 70 191 A0
179 Mineral oil 50 200 L
180 Muget hyacinth 70 178 FG
181 Phosclere P315C* 70 200 ---
182 Phosclere P576 (2)* 70 210 A0
183 Quinalidine 70 173 ---
184 Quinoline* 70 230 ---
185 Terpineol Prime No. 1 70 194 M, F
186 Firemaster BP-6 75 200 FR
187 benzylalcohol/l-
heptadecanol (50/50)* 70 204 ---
188 benzylalcohol/l-
heptadecanol (75/25)* 70 194 ___
* The liquid was extracted from the solid.
(1) Akzo Chemie Nv.'s trademark for its styrenated hindered
phenol
(2) Akzo Chemie Nv.'s styrenated hindered phenol.
Photomicrographs of the porous polymers of Examples
38 and 122 are illustrated in Figs. 28 and 29, respectively.
The photomicrographs, at 2000X amplification, show the cel-
lular structure with a significant amount of "foliage" uni-
formly present throughout the samples.
EXAMPLES 189 to 193
Examples 189 through 193 in Table VII illustrate the
formation of homogeneous porous polymer intermediates, by
pouring the solution into a glass dish to form cylindridal
blocks having a radius of about 1.75 inches and a depth of
-69-
l~Z~670
about 0.25 inch, except where indicated, from "~oryl" polymer
and the compatible liquids found to be ùseful, using the stan-
dard preparation procedure. In the indicated instances, the
microporous polymer was likewise prepared.
The details of preparation and the type of function-
ally useful liquid noted are set forth in Table VII:
TABLE VII
Type of
Functional
10Ex. ~o.(l) Liquid Type and Liquid /O Liq. C. Liquid
Aromatic Amine
189 diphenylamine 75 195 PE, A0
Diester
190 dibutylphthalate 75 210 L
Haloqenated Hydrocarbon
191 hexabromobiphenyl (2) 70 315 FR
Miscellaneous
192 ~,N-bis(2-hydroxyethyl)
tallowamine* 75 250 ---
- 20 193 N,N-bis(2-hydroxyethyl)
tallowamine 90 300 ---
:
(1) General Electric Company's "Noryl", a blend of polyphenyl-
ene oxide condensation polymer with polystyrene, having the
following properties was used: Specific Gravity, 73F.,
1.06, Tensile Strength, psi. at 73F., 9,600, Elongation
at break, % at 73F., 60, Tensile Modulus, psi. at 73 F.,
355,000, nad Rockwell Hardness, ~119.
(2) The "Noryl" microporous polymers formed with hexabromo bi-
phenyl and N,N-bis(2-hydroxyethyl) tallowamine were poured
to depths of 0.5 inch.
A photomicrograph of the microporous polymer of
Example 192 is illustrated in Fig. 25. The photomicrograph,
at 2500X amplification, shows the microcellular structure with
spherical resin deposits on the walls of the cells.
EXAMPLES 194 to 236
Examples 194 through 236 in Table VIII illustrate the
formation of homogeneous porous polymer intermediates, in the
-70-
llZ~670
form of cylindrical blocks having a radius of about 1.25 inches
and a depth of about 0.5 inch, from polypropylene ~"PP") and
the compatible liquids found to be useful, using the standard
preparation procedure. In addition, in the indicated examples,
blocks of about 6 inches in depth and/or thin films were made.
Also, as indicated, the microporous polymer was prepared.
me details of preparation and the type of function-
ally useful liquid noted are set forth in Table VIII:
TABLE VIII
PP
Type of
Functional
Ex. ~o.(l) Liquid Type and Liquid /O Liq. C. Liquid
Unsaturated Acid
194 10-undecenoic acid* 70 260 M
Alcohols
195 2-benzylamino-1-propanol70 260 ---
196 Ionol CP* 70 160 A0
197 3-phenyl-1-propanol 75 230 - -
198 salicylaldehyde ~70 185 PF
Amides -
199 N,~-diethyl-m-toluamide 75 240 IR
200 aminodiphenylmethane* 70 230 ---
201 benzylamine* 70 160 ---
202 ~-butylaniline 75 200 ---
203 1,12-diaminododecane* 70 180 ---
204 1,8-diaminooctane 70 180 ---
* The liquid was extracted from the solid.
-71-
llZ(~670
TABLE VIII (continued)
PP
Type of
Functional
Ex~ No.(l) Liquid Type and Liquid /O Liq. C. Liquid
Amides (continued)
205 dibenzylamine* 75 200 ---
206 N,N-diethanolhexylamine* 75 260 ---
207 N,N-diethanoloctylamine* 75 250 ---
208 N,N-bis-~ -hydroxyethyl
cyclohexylamine 75 280 ---
209 N,N-bis-(2-hydroxyethyl)
hexylamine 75 260 ---
210 N,N bis-(2-hydroxyethyl)
octylamine 75 260 ---
* me liquid was extracted from the solid.
(1) Phillips Petroleum Company's "Marlex"**polypropylene having
the following properties was used: Density, g/cm3, 0.908,
Melt Flow, g/10 min. Melting Point, F., 340, Tensile
Strength at yield, psi, 2"/min., 5000, Hardness Shore D, 73.
** Trade Mark
-72-
112(:~670
TABLE VIII (continued)
PP
Type of
Functional Thin
Ex. No. Liquid Type and Liquid % Liq. C. Liquid Film
Esters
211 benzylacetate* 75 200 ~
212 benzylbenzoate* 75 235 L, P, PF ---
213 butylbenzoate 75 190 L, P ---
214 dibutylphthalate* 75 230 L, P yes
215 methylbenzoate 70 190 L, P, PF ---
216 methylsalicylate* 75 215 L, P, PF ---
217 phenylsalicylate* 70 240 P ---
Ethers
218 dibenzylether 75 210 PF ---
219 diphenylether* 75 200 PF yes
Halocarbons
220 4-bromodiphenylether* 70 200 FR ---
221 1,1,2,2 tetrabromoethane* 70 180 FR ---
222 1,1, 2, 2 tetrabromoethane* 90 180 FR ---
Ketones
223 benzylacetone 70 200 --- ---
224 methylnonylketone 75 180 --- ---
* me liquid was extracted from the solid.
llZ~6~0
TABLE VIII (continued)
-
Type of
Functional Thin
Ex. No. Liquid Type and Liquid /O Liq. C. Liquid Film
Miscellaneous
225 N,N-bis(2-hydroxyethyl)
tallowamine* (1) & (2) 75 200 --- yes
226 N,N-bis(2-hydroxyethyl)
cocoamine (2) 75 180 --- ---
227 butylated hydroxy toluene 70 160 A0 ---
22~3 D.C. 550 Silicone Fluid (3) 50 260 S, L ---
229 D.C. 556 Silicone Fluid* 70 190 S, L ---
230 EC-53 75 210 --- ---
231 N-hydrogenated rapeseed di-
ethanol amine* 75 210 SF ---
232 N-hydrogenated tallow di-
ethanol amine - 75 225 SF ---
233 Firemaster BP-6 75 200 FR ---
234 NBC oil 75 190 --~
235 Quinaldine* 70 200 --~ ---
236 Quinoline* 75 220 M ---
-
* The liquid was extracted from the solid.
(1) A block of about 6 inches in depth was also prepared.
(2) A permanent internal antistatic agent, having the following
physical properties was used: Boiling Point, lmm ~Ig, C.,
170, Viscosity, SSU, 90F, 367.
(3) Dow Corning's trade mark for its phenylmethyl polysiloxane
having the following properties was used: Viscosity 115CS
and serviceable from -40 to 450F. in open systems, and to
600F. in closed systems.
Photomicrographs of the porous polymer of Example 225
are illustrated in Figs. 2 through 5. Ihe photomicrographs of
Figs. 2 and 3, at 55X and 550X amplification, respectively,
show the macro structure of the microporous polymer. The
photomicrographs of Figs. 4 and 5, at 2,200X and 5,500X ampli-
fication, respectively, show the microcellular structure of
-74-
llza67~
the polymer as well as the interconnecting pores.
EXAMPLES 237 to 243
Examples 237 through 243 in Table IX illustrate the
formation of homogeneous porous polymer intermediates, in the
form of cylindrical blocks having a radius of about 1.25 in-
ches and a depth of about 0.5 inch, from polyvinylchloride
("PVC") and the compatible liquids found to be useful, using
the standard preparation procedure. Many of the exemplified
intermediates were extracted to form porous polymers, as in-
dicated in the Table.
The details of preparation and the type of function-
ally useful liquid noted are set forth in Table IX:
-75-
llZ~671D
TABLE IX
PVC
Type of
Functional
Ex. No.(l) Liquid Type and Liquid /O Liq. C. Liquid
Aromatic Alcohols
237 4-methoxybenzyl-alcohol 70 150 PF
Other -(OH) Containin~ Compounds
238 1-3,-dichloro-2-propanol* 70 170 ---
239 menthol* 70 180 PF
240 10-undecene-1-ol* 70 204-
210 ---
Haloqenated
241 Firemaster T33P* (2) 70 165 FR
242 Firemaster T13P* (3) 70 175 FR
Aromatic Hydrocarbons
243 trans-stilbene 70 190 ---
* me liquid was extracted from the solid.
(1) me polyvinylchloride used was of dispersion grade made by
American Hoechst, having an inherent viscosity of 1.20, a
density of 1.40 and bulk density of 20.25 pounds per cubic
foot.
(2) Michigan Chemical Corporation's trademark for its tris
(1,3-dichloroisopropyl) phosphate fire retardant having the
following properties: Chlorine content, theoretical, %,
49.1; Phosphorous content, theoretical, %, 7.2, Boiling
Point, 4mm Hg, abs. C., 200 (decomposes at 200C.), Re-
fractive Index, 1.50.9, Viscosity, Brookfield, 73F.,
Centipoises, 2120.
Structure: ~ (ClCh2)2CHO~3 P-0
(3) Michigan Chemical Corporation's trademark for its tris-
halogenated propylphosphate flame retardant having the fol-
lowing properties: Specific Gravity, at 25 C./25C., 1.88,
Viscosity, at 25C., centistokes, 1928, Refractive Index,
1.540, pH, 6.4, Chlorine, %, 18.9, Bromine, %, 42.5, Phos-
phorous, %, 5.5.
A photomicrograph of the porous polymer of Example
242 is illustrated in Fig. 27. me photomicrograph, at 2000X
amplification, shows the extremely small cell size of this
microporous polymer in contrast to the cell structure exempli-
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fied by Figs. 7, 13, 18, 20, and 24, wherein the cell size is
larger and more readily observable at a comparable magnifica-
tion. The photomicrograph also shows the presence of a large
amount of resin masking the basic cell structure.
EXAMPLES 244 to 255
Examples 244 through 255 in Table X illustrate the for-
mation of homogeneous porous polymer intermediates, in the form
of cylindrical blocks having a radius of about 1.25 inches and
a depth of about 2.0 inches, from methylpentene ("MPP") polymer
and the compatible liquids found to be useful, using the stand-
ard preparation procedure. Many of the exemplified interme-
diates were extracted to form porous polymers, as indicated in
the Table.
The details of preparation and the type of function-
ally useful liquid noted are set forth in Table X:
~1~0670
TABLE X
MPP
Type of
Functional
Ex. No.(l) Liquid Type and Liquid % Liq. C. Liquid
Saturated Aliphatic Acid
244 decanoic acid* 75 230 ---
Saturated Alcohols
245 l-dodecanol* 75 230 ---
246 2-undecanol* 75 230 ---
247 6-undecanol* 75 230 ---
Amine
248 dodecylamine 75 230 FA
Esters
249 butylbenzoate* 75 210 L, P, PF
250 dihexylsebacate* - 70 220 L, P
Ethers
251 dibenzylether* 70 230 PF
_
* The liquid was extracted from the solid.
0 (1) Mitsui's methylpentene polymer having the following proper-
ties was used: Density, g.cc, 0.835, Melting Point C.,
235, Tensile Strength at Break, kg/cm2, 230, Elongation at
Break %, 30, Rockwell Hardness, R, 85.
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TABLE X (continued)
MPP
Type of
Functional
Ex. No. Liquid Type and Liquid /O Liq. C. Liquid
Hydrocarbons
252 l-hexadecene* 75 220 ---
253 naphthalene* 70 240 MR
Miscellaneous
254 EC-53* 75 230 A0
255 Phosclere P315C* 75 250 ---
-
* me liquid was extracted from the solid.
A photomicrograph of the porous polymer of Example 253
is illustrated in Fig. 22. The photomicrograph, at 2400X am-
plification, shows the extremely flattened cell walls, as com-
parable to the configuration observed in Fig. 14.
EXAMPLES 256 to 266
Examples 256 through 266 in Table XI illustrate the
formation of homogeneous porous polymer intermediates, in the
form of cylindrical blocks having a radius of about 1.25 inches
and a depth of about 0.5 inch, from polystyrene ("PS") and the
compatible liquids found to be useful, using the standard
preparation procedure. All of the exemplified intermediates
were extracted to form porous polymers.
The details of preparation and the type of functional-
ly useful liquid noted are set forth in Table XI.
TABLE XI
Type of
Functional
Ex. No.(l) Liquid Type and Liquid /O Liq. C. Liquid
256 Firemaster T-13P 70 250 FR
257 hexabromobiphenyl 70 260 FR
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TABLE XI (continued)
Type of
Functional
EX. No.(l) Liquid Type and Liquid % Liq. C. Liquid
258 Phosclere P315C 70 270 ---
259 Phosclere P576 70 285 A0
260 tribromoneopentylalcohol 70 210 FR
261 FR 2249 (2) 70 240 FR
262 Fyrol CEF (3) 70 250 FR
263 Firemaster T33P (4) 70 210 FR
264 Fyrol FR 2 (5) 70 240 FR
265 dichlorobenzene 80 160 MR, FR
266 l-dodecanol 75 --- ---
(1) Monsanto Chemical Company's "Lustrex" polystyrene having the
following physical properties was used: Impact Strength, ft.
lb./in notch (Inj. molded), 0.40, Tensile Strength, psi,
7500, Elongation, %, 2.5, Elastic Modulus, psi, XID5, 4.5,
Deflection Temp., under load 264, psi, F., 200, Specific
Gravity, 1.05, Rockwell Hardness, M-75, Melt Flow, g/10
min., 4.5.
(2) Dow Chemical Corporation's trademark for its fire retardant
having composition and properties: Tribromoneopentyl alco-
hol, 60%; Voranol CP. 3000 polyol, 40%, Bromine, %, 43,
hydroxyl No. 130, Viscosity, cps, 25C. (approx.) 1600,
Density, gm/cc, 1.45.
(3) Stauffer Chemical Company's trademark for its tris- -chloro-
ethyl phosphate fire retardant having the following proper-
ties: Boiling Point, at 0.5 mm Hg abs., C, 145, at 760 mm
Hg abs., C., decomposes, Chlorine content, wt. %, 36.7,
Phosphorous content, wt. %, 10.8, Refractive Index at 20C.,
1,4745; Viscosity, cps at 73F. (22.8C.), 40.
(4) Michigan Chemical Corporation's trademark for its tris(l,3-
dichloroisopropyl phosphate) fire retardant having the fol-
lowing properties: Chlorine content, theoretical, %, 49.1,
Phosphorous content, theoretical, %, 7.2, Boiling Point,
4 mm Hg abs., C, 200 (decomposes at 200C.), Refractive
Index, 1.5019, Viscosity, Brookfield, 73F., Centipoises,
2120.
Structure: ~ (ClCH2)2CH0]3 P-0
(5) Stauffer Chemical Company's trademark for its tris (di-
chloropropyl) phosphate flame retardant additive having the
following properties: Melting Point, F, Approx., 80, Re-
fractive Index nd at 25C., 1.5019, Viscosity, Brookfield
at 22.8C., cps, 2120.
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a670
A photomicrograph o~ the microporous polymer of Exam-
ple 260 is illustrated in Fig. 26. Although the cells are
small compared to the cells illustrated in Figs. 4, 7, 13, 18,
and 25, the basic microcellular structure is present.
EXAM2LE 267
This example illustrates the formation of a homogeneous
porous polymer intermediate from 30% high impact polystyrene
(1) and 70% hexabromobiphenyl, using the standard preparation
procedure and heating the mixture to 280C. me polymer inter-
mediate thus formed was about 2.5 inches in diameter and about0.5 inch in depth. me hexabromobiphenyl is useful as a flame
retardant and the porous intermediate is useful as a solid
flame retardant additive.
EXAMæLE 268 ~^
This example illustrates the formation of a homogeneous
porous polymer intermediate from 25% acrylonitrile-butadiene-
styrene terpolymer(2) and 75% diphenylamine, using the standard
preparation procedure and heating the mixture to 220C. The
polymer intermediate thus formed was about 2.5 inches in diame-
ter and about 2 inches in depth. m e microporous polymer wasformed by extracting the diphenylamine. me diphenylamine is
useful as a pesticide and antioxidant and the porous polymer
intermediate has the same utility.
(1) Union Carbide Company's "Bakelite" polystyrene for injection
molding having the following properties was used: Tensile
Strength, psi., (1/8" thick) 5000, ultimate elongation (1/8"
thick) 25, Tensile modulus, psi., (1/8" thick) 380,000,
Rockwell hardness (1/4 x 1/2 x 5") 90, Specific Gravity,
natural 1.04.
0 (2) Uniroyal's Kralastic* ABS polymer having the following pro-
perties was used: Specific Gravity, 1.07, impact strength
(1/8" Bar Sample), Izod ~otched, 73F., ft. lbs,/in. notch,
1.3-1.9, Tensile Strength, psi., 8,800, and Rockwell Hard-
ness, R, 118.
* Trademark
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EXAMPLES 269 and 270
The homogeneous porous polymer intermediates were
formed from 25% chlorinated polyethylene thermoplastic supplied
by Dow, having a melt viscosity of 15 poise, 8 percent crystal-
linity, and containing 36 per cent chlorine and 75% N,N-bis(2-
hydroxyethyl) tallowamine (Example 270) and 75% chlorinated
polyethylene thermoplastic and 25% l-dodecanol (Example 271),
using the standard preparation procedure and heating to 220C.
me porous polymer intermediates were about 2.5 inches in dia-
meter and about 2 inches in depth.
EXAMPLE 271
The homogeneous porous polymer intermediate was formed
using the standard preparation procedure and heating to 210C.
from 25% chlorinated polyethylene elastomer, as used in Example
271 and 75% diphenylether. The porous polymer intermediates
were about 2.5 inches in diameter and about 2 inches in depth.
The diphenylether is useful as a perfume and the intermediate
is also useful in perfumes.
EXAMPLES 272 to 275
Examples 272 through 275 in Table XII illustrate the
formation of homogeneous porous polymer intermediates, in the
form of cylindrical blocks having a radius of about 1.25 inches
and a depth of about 0.5 inch from styrene-butadiene ("SBR")
rubber (1) and the compatible liquids found to be useful using
the standard preparation procedure. In addition to the cyl n-
drical blocks, as indicated, thin films were also formed.
The details of preparation and the type of functional-
ly useful liquid noted are set forth in Table XII:
(1) Shell Chemical Company's Kraton* SBR polymer having the
following properties was used: Tensile Strength, psi.,
3100-4600, Elongation at Break, 880-1300, and Rockwell
hardness, Shore A, 35-70.
* Trademark
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670
TABLE XII
SBR
Type of
Functional ~hin
Ex. No. Liquid Type and Liquid/O Liq. C. Liquid Film
272 N,N-bis(2-hydroxyethyl)
tallow amine 80 195 --- yes
273 decanol* 70 190 PF yes
274 diphenylamine 70 200-
210 PE, A0 yes
275 diphenylether 70 195 PF yes
* The liquid was extracted from the solid
EXAMPLES 276 to 278
Examples 276 through 278 in Table XIII illustrate the
formation of homogeneous porous polymer intermediates, in the
form of cylindrical blocks having a radius of 1.25 inches and
~a depth of about 0.5 inch from "Surlyn" (1) and the compatible
liquids found to be useful, using the standard preparation pro-
cedure. In addition to the cylindrical blocks, as indicated,
thin films were also formed. Two of the exemplified interme-
diates were extracted to form porous polymers, as indicated in
the Table.
The details of preparation and the type of functional-
ly useful liquid noted are set forth in TABLE XIII:
(1) E. I. du Pont de Nemour's "Surlyn"* ionomer resin 1652, lot
number 115478, having the following properties was used:
Density, g/cc, 0.939, Melt Flow Index, decigm./min., 4.4;
Tensile Strength, psi., 2850, Yield Strength, psi., 1870,
Elongation, %, 580.
3Q * Trademark
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T~BLE XIII
SURLYN
Type of
Functional min
Ex. No.(l) Liquid Type and Liquid % Liq. C. Liquid Film
276 N,~-bis(2-hydroxyethyl)
tallowamine 70 190 --- yes
195
277 diphenylether* 70 200 PF yes
278 dibutylphthalate 70 195 L yes
.
* me liquid was extracted from the solid.
Photomicrographs of the porous polymer of Example 277
are illustrated in Figs. 23 and 24. Fig. 23, at 255X amplifi-
cation, shows the macrostructure of the polymer. Fig. 24, at
2550X amplification, illustrates the microcellular structure of
the polymer with slight "foliage" and relatively thick cell
walls, as compared with, for example, Fig. 25.
EXAMPLE 279
me homogeneous porous polymer intermediate was formed,
using the standard preparation procedure and heating to 200C.,
from a high density polyethylene-chlorinated polyethylene
blend, equal parts, and 75% l-dodecanol. The porous polymer
intermediate was cast in a film having a thic~ness of about
20 to 25 mils. me HDPE and CPE were utilized in previous
Examples.
EXAMPLE 280
me homogeneous porous polymer intermediate was formed,
using the standard preparation procedure and heating to 200C.,
from a high density polyethylene-polyvinylchloride blend, equal
parts, and 75% l-dodecanol. me intermediate thus formed was
about 2 inches in depth and about 2.5 inches in diameter. The
HDPE and PVC were as utilized in previous Examples.
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0670
EXAMPLE 281
The homogeneous porous polymer intermediate was formed,
usiny the standard preparation procedure and heating to 200C.,
from a high density polyethylene/acrylonitrile-butadiene-sty-
rene terpolymer blend, equal parts, and 75% l-dodecanol. The
intermediate thus formed was about 2 inches in depth and about
2.5 inches in diameter. The HDPE and ABS were as utilized in
previous Examples.
EXAMPLES 282 to 285
Examples 282 through 285 in Table XIV illustrate the
formation of homogeneous porous polymer intermediates, in the
form of cylindrical blocks having a radius of 1.25 inches and
a depth of about 2 inches, from low density polyethylene/
chlorinated polyethylene blend, equal parts, and the compatible
liquids found to be useful, using the standard preparation pro-
cedure. In Example 283, the aforementioned method was employed,
but the intermediate was cast into a film having a thickness of
about 20 to 25 mils~ The LDPE and CPE were as utilized in pre-
vious Examples.
The details of preparation and the type of functional-
ly useful liquid noted are set forth in Table XIV:
TABLE XIV
Type of
Functional
Ex. No. Liquid Type and Liquid % Liq. C. Liquid
282 l-dodecanol 75 200 ---
283 diphenylether 75 200 PF
284 diphenylether 50 200 PF
285 N,N-bis(2-hydroxyethyl)
tallowamine 75 200 ---
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EXAMPLES 286 and 287
The homogeneous porous polymer intermediates were
formed from a low density polyethylene/polypropylene blend,
equal parts, and 75% N,N-bis (2-hydroxyethyl) tallowamine
(Example 286) and low density polyethylene/polypropylene blend,
equal parts, and 50% N,N-bis (2-hydroxyethyl) tallowamine (Ex-
ample 287) using the standard preparation procedure and heating
to 220C. for Example 286 and to 270C. for Example 288. Both
porous polymer intermediates were about 2.5 inches in diameter
and about 2 inches in depth. m e LDPE and PP were as utilized
in previous Examples.
EXAMPLE 288
The homogeneous porous polymer intermediate was formed,
using the standard preparation procedure and heating to 200C.,
from 50% N,N-bis(2-hydroxyethyl) tallowamine and 50% polypropyl-
ene/polystyrene blend (25 parts polypropylene). The porous poly-
mer intermediates were about 2.5 inches in diameter and about
2 inches in depth. The PP and PS were as utilized in previous
Examples.
EXAMPLE 289
The homogeneous porous polymer intermediate was formed,
using the standard preparation procedure and heating to 200C.,
from 75% l-dodecanol and a polypropylene/chlorinated polyethyl-
ene blend, equal parts. The porous polymer intermediate was
about 2.5 inches in diameter and about 0.5 inch in depth. The
PP and CPE were as utilized in previous Exampl~s.
EXAMPLES 290 to 300
Examples 290 through 300 illustrate the polymer-com-
patible liquid concentration range useful for the formation of
a homogeneous porous polymer intermediate from high density
polyethylene and N,N-bis(2-hydroxyethyl) tallowamine. In each
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~12~)670
Example the intermediates were about 2 inches in depth and
about 2.5 inches in diameter. The HDPE was as utilized in
previous Examples.
me details of preparation and any physical charac-
teristics noted are set forth in Table XV:
TABLE XV
EX. No. % Liq. C. Remarks
290 95 275 very weak; no solid integrity;
not operable
291 90 --- very greasy' liquid leaching out,
upper liquid limit was exceeded
292 80 250 greasy
293 75 220 greasy
294 70 250 hard solid
295 65 220 ---
296 60 250 hard solid
297 55 220 ---
298 50 240-260 hard solid
299 40 260 hard solid
300 30 200 hard solid
A photomicrograph of the porous polymer of Example
300 is illustrated in Fig. 19, at 2000X amplification. me
cells are not clearly visible at this amplification. Fig. 19
can be compared to Fig. 17, at 2475X amplification, wherein
the cell sizes are also very small at a similar polymer con-
centration of 70%.
EX~MPLES 301 to 311
These examples illustrate the polymer-compatible
liquid concentration range useful for the formation of a homo-
geneous porous polymer intermediate from low density poly-
ethylene and N,~-bis(2-hydroxyethyl) tallowamine. In each
example the intermediate was about 0.5 inch in depth and about
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13670
2.5 inches in diameter. ~he LDPE was as utilized in previous
Examples.
The details of preparation and any physical charac-
teristics noted are set forth in Table XVI:
TABLE XVI
Ex . No . % Liq . C . Remarks
301 95 275 very weak, no solid integrity;
not operable
302 90 240 very greasy, liquid leaching out,
upper liquid limit was exceeded
303 80 260 hard solid
304 75 210 hard solid
305 70 210 hard solid
306 66 200 hard solid
307 60 280 hard solid
308 50 280-290 hard solid
309 40 285 hard solid
310 30 285 hard solid
311 20 280-300 hard solid
Photomicrographs of the porous polymers of Examples
303, 307 and 310 are illustrated in Figs~ 14-15 (at 250X and
2500X amplification, respectively), 16 (at 2500X amplifica-
tion), and 17 (at 2475X amplification), respectively. me
Figures show the decreasing cell size, from very large (Fig.
15, 20% polymer) to very small (Fig. 17, 70% polymer), with
increasing polymer content. me relatively flattened cell
walls of the 20% polymer, Example 303, are similar to the
methyl pentene polymer ~Fig. 22) and are observable in Fig. 14.
Fiq. 15 is an enlargement showing part of a cell wall illus-
trated in Fig. 14. The microcellular structure of the porous
polymer is observable in Fig. 16.
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670
EXAMPLES 312 to 316
Examples 312 to 316 illustrate the polymer-compatible
liquid concentration range useful for the formation of a homo-
geneous porous polymer intermediate from low density poly-
ethylene and diphenylether. In each example the intermediate
was about 0.5 inch in depth and about 2.5 inches in diameter.
The LDPE was as utilized in previous Examples.
The details of preparation and any physical charac-
teristics noted are set forth in Table XVII:
TABLE XVII
Ex. No. % Liq~ C. Remarks
312 90 185 very greasy, no solid integrity,
not operable
313 80 185 very greasy' near upper liquid
limit but still operable
314 75 200 wet, strong
315 70 190-200 slightly greasy
316 60 200 hard solid
EXAMPLES 317 to 321
Examples 317 to 321 illustrate the polymer-compatible
liquid concentration range useful for the formation of a homo-
geneous porous polymer intermediate from low density poly-
ethylene and l-hexadecene. In each Example the intermediate
was about 2 inches in depth and about 2.5 inches in diameter.
The LDPE was as utilized in previous Examples.
The details of preparation and any physical charac-
teristics noted are set forth in Table XVIII:
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TABLE XVIII
Ex. No. /O Liq. C. Remarks
317 90 180 good strength
318 80 180 little strength, operable
319 75 200 little strength, operable
320 70 177 ---
321 50 180 good strength
EXAMPLES 322 to 334
These examples illustrate the polymer-liquid concen-
tration range useful for the formation of a homogeneous porouspolymer intermediate from polypropylene and N,N-bis(2-hydroxy-
ethyl) tallowamine. In each example the intermediate was
about 0.5 inch in depth and 2.5 inches in diameter. In addi-
tion, as indicated, films were made. The PP was as utilized
in previous examples.
The details of preparation and any physical charac-
teristics noted are set forth in Table XIX:
TABLE XIX
Ex. No. /O Liq. C. Remarks Thin Film
322 90 200 quite wet yes
323 85 200 --- ---
324 80 200 strong yes
325 75 180 dry and hard yes
326 70 200 --- yes
327 65 210 --- ---
328 60 210 --- yes
329 50 200 --- yes
330 40 210 --- yes
331 36.8 175 white-crystalline ---
332 25 180 --- ---
333 20 180 --- yes
334 15 180 --- ---
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Photomicrographs of Examples 322, 326, 328, 330 and
333 are illustrated in Figs. 6 through 10, respectively (at
1325X, 1550X, 1620X, 1450X, and 1250X amplification, respect-
ively). me extre~ne foliage of the 10% polymer microporous
polymer is shown by Fig. 6, yet the microcellular structure is
still maintained. These Figures illustrate the decreasing
cell size as the amount of polymer is increased. However, the
microcellular structure is present in each example despite
-the small cell size.
EXAMPLES 335 to 337
The examples illustrate the polymer-compatible liquid
concentration range useful for the formation of a homogeneous
porous polymer intermediate from polypropylene and diphenyl-
ether. In each example the intermediate was about 0.5 inch in
depth and about 2.5 inches in diameter. In addition, as indi-
cated, thin films were also made. m e PP was a utilized in
previous examples.
The details of preparation and any physical charac-
teristics noted are set forth in Table XX:
TABLE XX
Ex. No. %/O Liq. C. Thin Film
335 90 200 yes
336 80 200 yes
337 70 200 yes
-
Photomicrographs of the porous polymer of Examples
35, 336 and 337 are illustrated in Fig. 11 (2000X amplifica-
tion), 12 (2059X amplification and 13 (1950X amplification).
me Figures illustrate that as the polymer concentration is
increased, the pore size decreases, Fig. 11 illustrates the
smooth cell walls, while Figs. 12 and 13 illustrate the cells
and connecting pores. In each of the Figures, the micro-
--91--
~lZ06~0
cellular structure is present.
EXAMPLES 338 to 346
m ese examples illustrate the polymer-compatible li-
quid concentration range useful for the formation of a homo-
geneous porous polymer intermediate from styrene-butadiene
rubber and N,N-bis(2-hydroxyethyl) tallowamine. In each ex-
ample the intermediate was about 0.5 inch in depth and 2.5
inches in diameter. In addition, as indicated, thin films
were made. me SBR was as utilized in previous Examples.
me details of preparation and any physical charac-
teristics noted are set forth in Table XXI:
TABLE XXI
Ex. No. /O Liq. C. Remarks Thin Film
338 90 200 weak, beyond the yes
upper liquid limit
339 80 195 rubbery yes
340 75 195 rubbery yes
341 70 195 rubbery yes
342 60 200 rubbery yes
343 50 not reported rubbery yes
344 40 not reported rubbery yes
345 30 not reported rubbery yes
346 20 not reported yes
Photomicrographs for the styrene-butadiene rubber
microporous polymer of Examples 339 and 340 are illustrated in
Figs. 20 (2550X amplification) and 21 (2575X amplification).
me Figures illustrate the microcellular structure of the
microporous polymers. Fig. 21 also shows the presence of
spherical polymer deposits on the cell walls.
EXAMPLES 347 to 352
Examples 347 through 352 illustrate the polymer-
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6'7(~
compatible liquid concentration range useful for the formation
of a homoqeneous porous pclymer intermediate from styrene-
butadiene rubber and decanol. In each Example the interme-
diate was about 0.5 inch in depth and 2.5 inches in diameter.
In addition, as indicated, thin films were made. The SBR was
as utilized in previous examples.
me details of preparation and any physical charac-
teristics noted are set forth in Table XXII:
TABLE XXII
Ex. No. /O Liq. Temp., C. Remarks min Film
347 90not reported beyond upper liquid
limit, not operable ---
348 80 190 rubbery yes
349 70 190 rubbery yes
350 60 190 rubbery yes
351 50 190 rubbery yes
352 40not reported rubbery ---
-
TABLE XXIII
Ex. No. /O Liq. ''C. Remarks
353 80 not reported ---
354 70 200-210 ---
355 60 215 ---
356 50 200-210 ---
.
EXAMPLES 357 to 361
Examples 357 through 361 illustrate the polymer-com-
patible liquid concentration range useful for the formation of
a homogeneous porous polymer intermediate from a "Surlyn" resin
as utilized in previous Examples and N,~-bis(hydroxyethyl)
tallowamine. In each Example the intermediate was about 0.5
inch in depth and 2.5 inches in diameter. In addition, as
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indicated, thin films were made.
The details of preparation and any physical charac-
teristics noted are set forth in Table XXIV:
TABLE XXIV
Ex. No. /O Liq. C. Thin Films
357 70 190-195 yes
358 60 190 yes
359 50 not reported yes
360 40 not reported yes
361 30 not reported yes
.
EXAMPLES 362 to 370
These examples illustrate the polymer-compatible li-
quid concentration range useful for the formation of a homo-
geneous porous polymer intermediate from a "Surlyn" resin as
utilized in previous Examples and diphenylether. In each ex-
ample the intermediate was about 0.5 inch in depth and about
2.5 inches in diameter. In addition, as indicated, thin films
were made.
The details of preparation and any physical charac-
teristics noted are set forth in Table XXV:
TABLE XXV
Ex. No. % Liq. C. Thin Films
362 90 207 yes
363 80 190 yes
364 70 200 yes
365 60 185 yes
- 366 50 not reported yes
367 40 not reported ---
368 30 not reported ---
369 20 not reported ---
370 10 not reported ---
,
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~za670
EXAMPLES 371 to 379
-
Examples 371 through 379 illustrate the polymer-compa-
tible liquid concentration range useful for the formation of a
homogeneous porous polymer intermediate from a "Surlyn" resin
as utilized in previous Examples and dibutylphthalate. In each
Example the intermediate was about 0.5 inch in depth and about
2.5 inches in diameter.
The details of preparation and any physical charac-
teristics noted are set forth in Table XXVI:
TABLE XXVI
Ex. No. /O Liq. C. Remarks
371 90 220 ---
372 80 208 ---
373 70 195 ___
374 60 200 ---
375 50 200 ___
376 40 not reported ---
377 30 not reported ---
378 20 not reported ---
379 10 not reported ---
.
PRIOR ART EXAMPLES 380-384
EXAMPLES 380 to 384
Examples 380 to 384 are reproductions of various prior
art compositions which are shown to have a physical structure
different from that of the present invention.
EXAMPLE 380
A porous polymer was prepared in accordance with the
process of Example 1 of U.S, Patent ~o. 3,378,507, as modified
to obtain a product with some physical integrity and to uti-
lize a soap as the water-soluble anionic surfactant, in place
of sodium bis(2-ethylhexyl) sulfosuccinate.
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0670
In a Brabender-Plasti-Corder internally heated blender,
33 1/2 parts by weight of Exxon Chemical Corporation type LD 606
polyethylene and 66 2/3 part of Ivory* soap flakes were mixed
at a machine temperature of about 350F., until a homogeneous
blend was formed. me material was then compression molded with
a rubber type mold having a 2.5 inch by 5.0 inch cavity of a
depth of 20 mils., at a temperature of about 350F. and a pres-
sure of 36,000 pounds per square inch. The resulting sample
was continuously washed for about three days in a slow flowing
stream of tap water and then sequentially washed by immersion
in eight distilled water baths, each for a period of about one
hour. me resulting sample still retained some soap and had
poor handling properties.
Figs. 47 and 48 are photomicrographs of the product
of Example 380, at 195X and 2,000X amplification, respectively.
It is apparent that the product is relatively non-uniform
polymeric structure having neither distinct cellular cavities
not interconnecting pores_
EXAMPLE 381
A porous polymer was prepared in accordance with the
process of Example 2, sample D, of U.S. Patent No. 3,378,507,
as modified to obtain a sample having some handling strength.
In a Brabender-Plasti-Corder internally heated blender,
75 parts of Ivory soap flakes and 25 parts of Exxon Chemical
Corporation type LD 606 polyethylene were mixed at a machine
temperature of about 350F. and a sample temperature of about
330F. until a homogeneous blend was formed. The material was
then injection-molded in a one-ounce Watson-Stillman injection
molding machine having a mold cavity diameter of two inches
and a depth of 20 mils. The resulting sample was continuously
washed for about three days in a slowly flowing stream of tap
* Trade Mark
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llZU~ 70
water and then sequentially washed by immersion in eight dis-
tilled water baths, each for a period of about one hour. m e
resulting sample still retained some soap.
Figs. 45 and 46 are photomicrographs of the product of
Example 381, at 240X and 2400X amplification, respectively.
me product of this example does not have the typical cellular
structure of the present invention, as is apparent from the
photomicrographs.
EXAMPLE 382
In accordance with the process of Example 3, sample A,
of U.S. Patent No. 3,378,507, a porous polymer was prepared.
In a Brabender-Plasti-Corder internally heated blender,
25 parts of Novamont Corporation type F300 8~19 polypropylene
and 75 parts of Ivory soap flakes were mixed at a machine tem-
perature of about 330F. until a homogeneous blend was formed.
The material was then compression molded with a rubber type
mold. me resulting sample was found to have very little
strength. A portion of the resulting sample was continuously
washed for about three days in a slowly flowing stream of tap
water and then sequentially washed by immersion in eight dis-
tilled water baths, each for a period of about one hour. me
washed product was found to have extremely poor handling cha-
racteristics.
Figs. 51 and 52 are photomicrographs of the product of
Example 382 at 206X and 2000X amplification, respectively. me
photomicrographs show that the product does not have the cel-
lular structure of the present invention.
EXAMPLE 383
me process of Example 3, sample A, of U.S. Patent
No. 3,378,507 was modified to obtain a product having improved
handling strength.
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llZ067~
On an open two roll rubber mill, manufactured by the
Bolling Company, 25 parts of Novamont Corporation type F300
8Nl9 polypropylene and 75 parts of Ivory soap flakes were
mixed for about ten minutes at a temperature of about 350F.
until a homogeneous blend was formed. The material was then
injection molded with a one-ounce Watson-Stillman injection
molding machine having a mold cavity diameter of two inches and
a depth of 20 mils. The resulting sample was continuously
washed for about three days in a slowly flowing stream of
tap water and then sequentially washed by immersion in eight
distilled water baths, each for a period of about one hour.
The resulting sample still retained some soap. The resulting
product was found to be stronger than the product of Example
382.
Figs. 49 and 50 are photomicrographs of the product of
Example 383 at 195X and 2000X amplification, respectively. The
irregular shapes shown by the photomicrographs are readily
distinguishable from the structure of the present invention.
EXAMPLE 384
A porous polymer was prepared in accordance with Exam-
ple II of U.S. Patent No. 3,310,505, as modified to obtain a
more homogeneous mixing of the materials.
In a Brabender-Plasti-Corder internally heated blender,
40 parts of Exxon Chemical Corporation type LD 606 polyethylene
and 60 parts of Rohm and Haas Corporation polymethylmethacry-
late were mixed, for about 10 minutes, at a machine tempera-
ture of about 350F. until a homogeneous blend was formed. The
material was then sheeted on a cold mill and subsequently com-
pression molded using a heated four-inch circular die with
a depth of 20 mils. and 30 tons of pressure for about ten
minutes. The resulting composition was extracted for 48 hours
with acetone in a large Soxlet extractor.
-98-
~Z~
Figs. 53 and 54 are photomicrographs of the product of
Example 384 at 205X and 2000X amplification, respectively.
me non-uniform structure shown by the photomicrographs is
easily distinguished from the uniform structure of the present
invention.
PHYSIC~L CHARACTERIZATION OF
EXAMPLES 225 and 358
,
To obtain a quantitative understanding of the homoge-
neous structure of the present invention, certain samples of
the microporous material and certain prior art samples were
analyzed on an Aminco mercury intrusion porosimeter. Figs.
30 and 31 are mercury intrusion curves of the one-half inch
block of Example 225 which was made with 25 per cent polypropyl-
ene and 75 per cent N,N-bis(2-hydroxyethyl) tallowamine, and
Fig. 32 is a mercury intrusion curve of the 6 inch block of
Example 225. A11 mercury intrusion curves are shown on a
semi-log graph with the equivalent pore sizes shown on the
log scale abscissa. Figs. 30 through 32 show the typical
narrow distribution of pore sizes in the composition of the
instant invention. It was determined that the one-half inch
sample of Example 225 has a void space of about 76 per cent
and an average pore size of about 0.5 micron and the 6 inch
block has a void space of about 72 per cent and an average
pore size of about 0.6 micron.
Fig. 33 is a mercury intrusion curve of the product of
Example 358 which was made with 40 per cent polypropylene
and 60 per cent N,N-bis(2-hydroxyethyl) tallowamine. Fig. 33
shows that the sample has the typical narrow pore size distri-
bution. It was determined that the sample had a void space of
about 60 per cent and an average pore size of about 0.15
micron.
_99 _
~lZ~670
It is readily apparent that the compositions of this
invention have such pore size distributions that at least 80
per cent of the pores present in the composition fall within
no more than one decade on the abscissa of the mercury intru-
sion curve. The pore size distribution of the composition may
thus be characterized as "narrow".
PHYSICAL CHARACTERIZATION OF
PRIOR ART COMMERCIAL COMPOSITIO~S
EXAMPLE 385
The composition of this example is commercially avail-
able Celgard 3501 microporous polypropylene, manufactured by
Celanese. Fig. 34 is a mercury intrusion curve of the sample
showing a large population of pores in the range of 70 to 0.3
microns. The sample was determined to have a void space of
about 35 per cent and an average pore size of about 0.15
microns.
EXAMPLE 386
me composition of this example is commercially avail-
able A-20 microporous polyvinylchloride, manufactured by Ame-
race. Fig. 35 is a mercury intrusion curve o the sample andshows a very broad pore size distribution. The sample was
determined to have a void space of about 75 per cent and an
average pore size of about 0.16 microns.
EXAMPLE 387
The composition of this example is commercially avail-
able A-30 microporous polyvinylchloride and manufactured by
Amerace. Fig. 36 is a mercury intrusion curve of the sample
and shows a very wide pore size distribution. me sample was
determined to have a void space of about 80 percent and an
average pore size of about 0.2 microns.
EXAMPLE 388
me composition of this example is commercially avail-
--1 00--
~ 6~
able Porex microporous polypropylene. Fig. 37 is a mercuryintrusion curve of the sample showing a very broad distribu-
tion of extremely small cells as well as a distribution of
very large cells. The sample was determined to have a void
space of about 12 per cent and an average pore size of about
one micron.
EXAMPLE 389
The composition of this example is commercially avail-
able Millipore BDWP 29300 microporous polyvinylchloride. Fig.
38 is a mercury intrusion curve of the sample showing a rela-
tively narrow distribution in the range of 0.5 to 2 microns as
well as a number of cells smaller than about 0.5 micron. m e
sample was determined to have a void space of about 72 per cent
and an average pore size of about 1.5 microns.
EXAMPLE 390
The composition of this example is commercially avail-
able Metricel TCM-200 microporous cellulose triacetate manufac-
tured by Gelman. Fig. 39 is a mercury intrusion curve of the
sample showing a broad pore size distribution up to about 0.1
micron. The sample was determined to have a void space of
about 82 per cent and an average pore size of about 0.2 micron.
EXAMPLE 391
The composition of this example is commercially avail-
able Acropor WA microporous acrylonitrile-polyvinylchloride co-
polymer manufactured by Gelman. Fig. 40 is a mercury intrusion
curve of the sample showing a broad pore size distribution. The
sample was determined to have a void space of about 64 per cent
and an average pore size of about 1.5 microns.
PHYSICAL CHARACTERIZATIO~ OF PRIOR ART
EXAMPLES 380 to 384
The products of prior art Examples 380 to 384 were
--101--
0670
also analyzed by mercury intrusion. Figs. 41-43 are mercury in-
trusion curves showing the broad pore size distribution of the
products of Examples 381, 380, and 383, respectively. Fig. 44
is a mercury intrusion curve for the product of Example 384,
showing a population of pores in the range of 45 to 80 microns
as well as a number of extremely small pores. The products of
Examples 380, 381, 383, and 384 were determined to have void
spaces of about 54, 46, 54, and 29 per cent and average pore
sizes of about 0.8, 1.1, 0.56, and 70 microns, respectively.
EXAMPLES 392 to 399
These examples illustrate the polymer/compatible liquid
concentration range useful for the formation of homogeneous
porous polymer intermediates from polymethylmethacrylate and
1,4-butane diol using the standard preparation procedure. In
each example the intermediate formed was about 0.5 inches in
depth and about 2.5 inches in diameter. The polymethylmetha-
crylate was supplied by Rohm and Haas under the designation
Plexiglas Acrylic Plastic Molding Powder, lot number 386,491.
me details of preparation are set forth in Table XXVII:
TABLE XXVII
EXAMPLE NO. /O LIQUID TEMP., C.
392 90 215
393 85 225
394 80 225
- 395 70 210
396 60 229
397 50 230
398 40 229
399 30 225
30The 1,4-butanediol was removed from the product of
Example 395 and the resultant structure was determined to be
--102--
~6;70
the cellular structure of the present invention, as may be seen
from Fig. 61 which shows the microporous product at 5000X am-
plification. ~he same polymer/liquid system as that of Example
394 was also cooled at rates up to 4000C per minute and still
produced the cellular structure of the present invention.
EXAMPLE 400
~ he porous polymer intermediate was prepared using the
standard preparation procedure and heating 30 per cent poly-
methylmethacrylate, as utilized in the previous examples, and
70 per cent lauric acid to 175C and cooling to form the porous
polymer intermediate. me lauric acid was removed from the
resultant intermediate to form the microporous cellular struc-
ture of the present invention.
EXAMPLE 401
The porous polymer intermediate was prepared using the
standard preparation procedure and heating 30 per cent Nylon
11, supplied by Aldrich Chemical Company, and 70 per cent ethyl-
ene carbonate to a temperature of 218C and then cooling the
resultant solution to form the porous polymer intermediate.
me ethylene carbonate was removed from the intermediate and
the resultant microporous polymer was determined to have the
cellular structure of the present invention.
EXAMPLE 402
e porous polymer intermediate was prepared using
the standard preparation procedure and heating 30 per cent
Nylon 11, as utilized in the previous example, and 70 per cent
1,2-propylene carbonate was removed from the intermediate and
the resultant microporous polymer was determined to have the
cellular structure of the present invention.
EXAMPLES 403-422
Examples 403-422 demonstrate the formation of the
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porous polymer intermediates from polymer/liquid systems con-
taining various amounts of Nylon 11, as utilized in previous
Examples, and tetramethylene sulfone, supplied by Shell under
the designation Sulfone W, and containing approximately 2.5
per cent water. The various concentrations were cooled at
various rates and from various solution temperatures, as indi-
cated in Table XXVIII, which also demonstrates that increased
cooling rates and increased concentration of the polymer cause
the resulting cell sizes to decrease, in general.
TABLE XXVIII
Cooling Rate Cell Size
Ex. No. /O Li~. T CC/Min. (Microns)
403 90 195 20 10
404 80 198 5 15
405 80 198 20 14
406 80 198 40 9
407 80 198 80 5.5
408 70 200 5 11
409 70 200 20 5
410 70 200 40 6.5
411 70 200 80 6.5
412 60 205 5 5.
413 60 205 20 4.5
414 60 205 40 4
415 60 205 80 3.5
416 50 210 20 3
417 50 210 40 1.5
418 50 210 80 2
419 60 212 20 ---
420 70 215 20 ---
421 80 217 20 ---
422 90 220 20 ---
-104-
The foregoing Table XXVIII also demonstrates that at
concentrations from 40 per cent to 10 per cent liquid, there
is no resulting visible porosity, for the system cooled at 20C
per minute. Such results are entirely anticipated as may be
seen by referring to Fig. 62 which shows the melt curve for the
~ylon ll/tetramethylene Sulfone concentration range, as well as
the crystallization curves at the various rates of cooling. It
is apparent from Fig. 62 that at 20C/minute cooling rate, the
system containing 40% liquid does not fall within the substan-
tially flat portion of the crystallization curve and thuswould not be expected to form the desired microporous structure.
Fig~ 63 is a photomicrograph at 2000X amplification of Example
409 showing the typical cellular structure of Examples 403-418.
EXAMPLE 423
The porous polymer intermediate was prepared by using
the standard preparation procedure and heating 30 per cent poly-
carbonate supplied by General Electric under the designation
Lexan* and 70 per cent menthol to a temperature of 206C and
cooling to form the porous polymer intermediate. The menthol
was extracted and a cellular microporous structure resulted as
shown in Fig. 64, which is a photomicrograph of the product of
this Example at 2000X amplification.
EXAMPLE 424
m is example demonstrates the formation of the micro-
porous cellular structure of the present invention from poly-
2,6-dimethyl-1,4-phenylene oxide, supplied by Scientific Poly-
mer Products, commonly referred to as polyphenylene oxide.
me homogeneous microporous polymer intermediate was made from
30 percent of said polyphenylene oxide and 70 percent ~,~-bis-
(2-hydroxyethyl) tallowamine which was heated to a solution
* Trade Mark
-105-
l~Z~)670
.
temperature of 275C and the intermediate was formed using
the standard preparation procedure. The liquid was removed
from the intermediate and the cellular structure of the present
invention resulted, as may be seen from Fig. 65 which is a
photomicrograph of the product of this Example at 2000X am-
plification.
EXAMPLE 425
mis Example demonstrates the formation of the non-
cellular product of this invention by cooling a homogeneous
solution of 40 percent polypropylene, as utilized in the pre-
vious Examples, and 60 percent dibutyl phthalate. The solu-
tion was extruded onto a chilled belt at a thickness of about
10 mils and the cooling rate was in excess of 2,400C. A
quantity of dispersol was applied to the surface of the belt at
a point prior to the solution being extruded thereon. The li-
quid was removed from the resultant film and a non-cellular
microporous product resulted, as may be seen from Fig. 65
which is a photomicrograph of the product of this Example at
2000X amplification.
EXAMPLE 426
This Example demonstrates the formation of the non-
cellular product of this invention by cooling a homogeneous
solution of 25 percent polypropylene, as utilized in previous
examples, and 75 percent N,N-bis(2-hydroxyethyl) tallowamine
in the same manner as that of Example 425. m e liquid was
removed from the resultant film and a non-cellular microporous
product resulted, as may be seen from Fig. 67 which is a photo-
micrograph of the product of this Example at 2000X amplifica-
tion.
m e products of Examples 425 and 426 were analyzed by
mercury intrusion porosimetry and their respective intrusion
-106-
~2~i'~
curves are shown in Figs. 68 and 69. It is apparent that both
products have generally narrow pore size distributions, but
the product of Example 426 demonstratés a much narrower distri-
bution than the product of Example 425. Thus, the product of
Example 425 has a calculated S value of 24.4 whereas the pro-
duct of Example 426 has a calculated S value of only 8.8. me
average pore size of Example 425 is, however, very small, 0.096
microns, whereas the average pore size of the product of Exam-
ple 426 is 0.589.
To quantitatively demonstrate the uniqueness of the
cellular compositions of the present invention, a number of such
microporous products were prepared in accordance with the
standard preparation procedure and the details relating there-
to are summarized in Examples 427-457 in Table XXIX. me
products of said Examples were analyzed by mercury intrusion
porosity to determine their respective average pore diameter
and the S value and by scanning electron microscopy to deter-
mine their average cell size, S. me result of such analysis
are shown in Table XXX.
TABLE XXIX
Solution
Ex. No. PolYmer Liauid % Void Temp. C.
427 polypropylene N,N-bist2-hydroxy-
ethyl) tallowamine 75 180
428 polypropylene N,N-bis(2-hycroxy-
ethyl) tallowamine 60 210
429 polypropylene diphenylether 90 200
430 polypropylene diphenylether 80 200
431 polypropylene diphenylether 70 200
432 polypropylene 1,8-diaminooctane 70 180
433 polypropylene phenylsalicylate 70 240
434 polypropylene 4-bromodiphenylether 70 200
435 polypropylene tetrabromoethane 90 180
-107-
:~C~'7V
TABLE XXIX (continued)
-
Solution
Ex. No. Polymer Liquid/O Void Temp. C
436 polypropylene N-octyldiethanol-
amine 75 ---
437 polypropylene N-hexyldiethanol-
amine 75 260
438polypropylene salicylaldehyde 70 185
439low density
polyethylene hexanoic acid 70 190
440 low density
polyethylene l-octanol 70 178
441 low density
polyethylene dibutyl sebacate 70 238
442 low density
polyethylene Phosclere EC-53 70 191
443 low density
polyethylene dicapryl adipate 70 204
444 low density
polyethylene diisooctyl phthalate 70 204
44S low density
polyethylene dibutyl phthalate 70 290
446 high density N,N-bis(2-hydroxy
polyethylene ethyl) tallowamine 80 250
447 polystyrene l-dodecanol 75 220
448 polystyrene 1,3-bis(4-piperidine)
propane 70 186
449 polystyrene diphenylamine 70 235
450 polystyrene N-hexyldiethanol-
amine 75 260
451 polystyrene Phosclere P315C 70 270
452 polymethyl-
methacrylate 1,4-butanediol 70 ---
453 polymethyl-
methacrylate 1,4-butanediol 85 ---
454 Surlyn diphenylether 70 185-207
455 Surlyn dibutyl phthalate 70 195
456 Noryl N,N-bis(2-hydroxy-
ethyl) tallowamine 75 250
; 40 457 Nylon 11ethylene carbonate 70 ---
_108-
~1;Z06~0
TABLE XXX
Ex. No. _ P C/P S loq C/P loq S/C
427 5.0 0.520 9.6 2.86 0.982 -0.243
428 3.18 0.112 28.4 5.0 1.45 0.197
429 22.5 11.6 1.94 4.52 0.288 -0.697
430 6.49 0.285 22.8 27.1 1.36 0.621
431 6.72 0.136 49.4 7.01 1.69 0.0183
432 13.0 0.498 26.1 2.36 1.42 -0.741
433 13.8 0.272 50.7 4.29 1.71 -0.507
434 3.35 0.137 24.5 5.25 1.39 0.195
435 15.4 0.804 19.2 5.13 1.28 -0.477
436 16.6 0.850 19.5 2.52 1.29 -0.819
437 20.0 0.631 31.7 2.51 1.50 -0.901
438 7.9 0.105 75.2 3.22 1.88 -0.390
439 7.5 1.16 6.47 8.62 0.811 0.0604
- 440 6.8 1.00 6.8 3.53 0.833 0.285
441 5.85 0.636 9.20 6.07 0.964 0.0160
442 3.40 0.512 6.64 5.30 0.822 0.193
443 5.0 0.871 5.74 8.21 0.759 0.215
444 4.75 0.631 7.53 3.54 0.877 -0.128
445 7.8 1.18 6.61 3.82 0.820 -0.310
446 34.5 0.696 49.6 4.34 1.70 -0.900
447 28.2 1.88 15.0 3.40 1.18 -0.919
448 1.08 0.0737 14.7 2.87 1.17 0.424
449 6.65 0.631 10.5 63.5 1.02 0.980
450 7.4 0.164 45.1 3.74 1.65 -0.296
451 1.4 0.151 9.27 2.26 0.967 0.208
452 9.2 0.201 45.8 3.68 1.66 -0.398
453 114 10.3 11.1 5.19 1.05 -1.34
454 6.8 0.631 10.8 2.13 1.03 -0.504
455 5.6 0.769 7.28 2.09 0.862 -0.428
456 19.0 0.179 106 2.74 2.03 -0.841
457 5.8 0.372 15.6 7.56 1.19 0.112
- 109 -
;'70
TABLE XXXI
Ex. No. Prior Art Description Polymer Type
458 Celgard 3501 polypropylene .45g Amerace A-30 polyvinylchloride
460 Porex polypropylene
461 Millipore EG cellulosic
462 Metricel GA~8 cellulosic
463 Sartorius SM 12807 polyvinylchloride
464 Millipore HAWP cellulosic
465 Millipore G5WP 04700 cellulosic
466 Millipore VMWP 04700 cellulosic
467 Amicon 5UM05 cellulosic
468 Celgard 2400 polypropylene
469 Millipore SMWP 04700 polyvinylchloride
470 Celgard 2400 polypropylene
471 Product of Example 381 polyethylene
472 Product of Example 380 polyethylene
473 Product of Example 383 polypropylene
474 Product of Example 384 polyethylene
--110--
TABLE XXXI I
Ex No . C S 1 oq S /C
458 0.04* 2.32 1.76
459 0.3 138 2.66
460 186 2.41 -1.89
461 0.2* 26.3 1.85
462 0.2* 9.14 1.66
463 0.2* 31.5 2.2
464 0.8* 2.94 0.565
10 465 0.22* 1.64 0.872
466 0.05* 5.37 2.03
467 2.10** 61.8 1.79
468 0~02* 5.08 2.40
469 5* 1.55 -0.509
470 0.04* 5.64 2.15
471 1.1** 11.5 1.019
472 0.8** 17.5 1.34
473 0.56 16.8 1.477
474 70 1.34 -1.718
. .
* From company product information
** From mercury intrusion
The data contained in Tables XXIX through XXXII is sum-
marized in Fig. 70 which is a plot of the log S/C vs. log C/P.
From Fig. 70 it is apparent that the cellular structure of the
present invention may be defined at having a log C/P of from
about 0.2 to about 2.4 and a log S/C of from about -1.4 to
about 1.0, and more usually said polymer will have a log C/P
of from about 0.-6 to about 2.2 and a log S/C of from about
-0.6 to about 0.4.
Ihus, as has been seen, the present invention provides
a facile method for preparing microporous polymers any synthetic
thermoplastic polymer in widely varying thicknesses and shapes.
--111--
~ ~oti~o
~he microporous polymers may possess a unique microcellular
configuration and are in any event characterized by pore dia-
meters with relatively narrow size distribution. These struc-
tures are formed by first selecting a liquid that is compatible
with a polymer, i.e. - forms a homogeneous solution with the
polymer and can be removed from the polymer after cooling and
then selecting the amount of the liquid and carrying out the
cooling of the solution in a fashion which insures that the
desired microporous polymer configuration will result.
As can be also seen, the present invention also provides
microporous polymer products which contain relatively large
amounts of functionally useful liquids such as a polymer addi-
tive and behave as a solid. These products may be advantageous-
ly utilized in a variety of applications such as, for example,
in masterbatching.
~ his application is a division of Canadian Patent
Application Ser. No. 285,080 filed on August 19, 1977.
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