Note: Descriptions are shown in the official language in which they were submitted.
CA 02340555 2005-03-29
A PROCESS FOR MANUFACTURING A. FLOOR COVERING
HAVING A FOAMED BACKING FORMED FROM
g RECYCLED POLYMERIC MATERIAL
Background and Field of the Invention
The present invention relates to recycling and reclaiming waste polymeric
material, and forming an article therefrom, and more particularly forming a
floor
covering utilizing the recycled and reclaimed waste polymeric material. .
There has been an increased interest in recycling, reclaiming and
reutilizing waste and scrap material, and particularly waste thermoplastic
polymeric material from a variety of sources. The recycling of most mixtures
of
thermoplastic scrap material is limited by the incompatibility of the various
rage iyv.
different kinds of thermoplastic and non-thermoplaslic material present in the
CA 02340555 2001-03-12
scrap. For example, the various thermoplastic resins are often insoluble in
each
other resulting in a heterogeneous mixture in which each type of resin forms a
dispersed phase in the other. This often adversely affects the mechanical
properties (e.g. tensile and impact strength) and aesthetic properties of any
articles formed from such a mixture.
One suggestion to overcome this problem is to sort the scrap material
based on the specific thermoplastic material present. Such sorting, however,
is
often impractical from both a technical and economic standpoint. Thus, various
other solutions have been proposed with respect to recycling waste polymeric
material. For example, U.S. Patent No. 4,250,222 to Mavel et al. proposes
coarsely grinding a mixture of two or more mutually incompatible thermoplastic
resins, incorporating into the coarsely ground thermoplastic resin mixture,
through the application of heat and pressure, from about 5 to about 25 parts
of
weight of a fibrous material, and forming the resin/fiber mass into an
article.
U.S. Patent No. 4,968,462 to Levasseur proposes shredding or granulating
polymeric waste, drying the material to a water content of not more than 8% by
weight, preheating the material to a temperature of 80°C to
160°C, kneading at a
temperature of 120°C to 250°C and injection molding or extruding
the material to
form a product such as a fence post.
Processes for recycling floor covering have also been desired inasmuch
as a particularly large amount of scrap material is generated during the
manufacture of floor covering. For example, in the manufacture of tufted
carpet,
the tufted carpet may have nylon pile secured in a primary backing of a woven
polypropylene fabric, which has a secondary vinyl plastic backing. The pile,
the
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primary backing and secondary backing are typically each a thermoplastic
having
different characteristics.
Specific to recycling carpet, U.S. patent No. 4,028,159 to Norris proposes
a process for reclaiming selvedge formed during manufacturing. The process
comprises heating the selvedge in air to a temperature above the melting
points
of the resins to melt and degrade the resins; separating melted resin from
solid
residue to reclaim meltable resin from the selvedge; and utilizing the
reclaimed
resins as a substitute for at least a portion of the high molecular weight
resins in
an adhesive mixture in subsequent carpet production.
U.S. Patent No. 4,158,645 to Benkowski et al. proposes applying a
shearing force (e.g., using a Banbury mixer) to tear the fabric fibers into
lengths
no greater than about 0.25 inch. This forms a mixture of thermoplastic-resin
and
short lengths of fabric fibers. The resulting mixture is subjected to heat and
pressure, such as by a drop mill and thus banded. After the mixture is banded,
it
can be calendared onto a web of fabric to form a finished reinforced sheet or
extruded into various continuous forms such as sheets or strips. The process
is
described as being particularly useful as applied to scrap polyvinyl chloride
sheet
material reinforced with cotton fabric.
These processes of recycling or reclaiming scrap material, however, are
not entirely successful and have not found widespread usage because of
economic infeasibility and limitations on the types of article, which can be
made.
Thus, it is among the objects of the invention to provide an improved process
of
recycling, reclaiming, and reutilizing scrap material, and particularly
thermoplastic
scrap material from the manufacture of floor covering or the subsequent
removal
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of the floor covering after installation.
It is another object of the present invention to provide a new floor covering
using the recycled and reclaimed scrap material. This new floor covering would
include both carpet tiles and roll goods of either woven or tufted
construction of
varying widths having a secondary backing comprised primarily of the recycled,
reclaimed scrap material. The secondary backing could be made of a continuous
solid phase material or a reduced density discontinuous phase where air or
another dissimilar material is incorporated. The secondary backing could have
a
pressure sensitive adhesive layer for removably attaching the new floor
covering
to a floor.
It is yet another object of the present invention to provide a method of
manufacturing a floor covering having a reduced density secondary backing
formed from recycled and reclaimed scrap polymeric material.
A further object of the present application is to provide an article of
manufacture made from an improved process of recycling, reclaiming,
reutilizing
and extruding scrap material, and particularly thermoplastic scrap material
from
the manufacture of floor covering or the subsequent removal of the floor
covering
after installation.
Another object of the present application is to provide building materials,
car parking stops, highway guardrail offset blocks, mats, sea walls, sound
barrier
walls and other similar products made from the recycled and reclaimed scrap
material. Other objects and advantages of this invention will become apparent
from the following description taken in connection with the accompanying
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drawings wherein are set forth, by way of illustration and example, certain
embodiments of this invention.
Summary of the Invention
These and other objects and advantages of the present invention are
accomplished by an extrusion process for recycling waste polymeric material
comprising a mixture of waste polymeric material wherein the waste polymeric
material may include from about 0 to 40 percent aliphatic polyamide or other
materials; granulating the chopped mixture into fragments at least an order of
magnitude smaller than the size of the waste polymeric material; densifying
the
granulated chopped mixture into fragments having a more uniform and solid
consistency; and extruding the densified granulated mixture at a temperature
of
less than the temperature at which the components of the waste material
decompose for making various articles of manufacture. The process of the
present invention can also include a profile extrusion process that utilizes
cooling
water for cooling the extruded material to form a desired profile shape, a
conveyor gripping motor for pulling the cooled extruded material into a
cutting
section for cutting the cooled extruded material into a desired size for
making
various articles of manufacture.
The present invention also provides for a floor covering. The floor covering
described herein includes, but is not limited to, a carpet or tile having
textile fibers
defining a fibrous upper face which are tufted into a primary backing or a
woven
fibrous upper face and a secondary backing permanently adhered to the lower
surface of the primary backing of the tufted articles or to the lower surface
of the
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woven article, the secondary backing comprising a matrix formed by an
extrusion
recycling process that includes the steps of granulating a coarsely chopped
mixture of waste polymer material including, but not limited to, 0 to 40
percent
aliphatic polyamide material, densifying the granulated chopped mixture into
fragments having a more uniform and solid consistency, extruding the densified
granulated mixture at a temperature of less than the temperature at which the
components of the waste material decompose and calendering the extruded
granulated material to provide the secondary backing layer for a carpet or a
tile.
A low density discontinuous phase secondary backing layer can be achieved by
the incorporation of an activated chemical blowing agent mixture or by the
incorporation of a variety of lower density materials along with the densified
granulated chopped mixture.
In an illustrative embodiment of the present invention, a process for
manufacturing a backing material for a floor covering comprises chopping a
mixture of waste polymeric material wherein the waste polymeric material has
about 0.1 to 40 percent aliphatic polyamide material having a predetermined
melting temperature. The chopped mixture is granulated into fragments that are
smaller than the original size of the waste polymeric material. The process
further
comprises the steps of densifying the granulated mixture into pelletized waste
polymeric material and mixing the waste polymeric material with a blowing
agent
having a predetermined decomposition temperature. The mixed waste polymeric
material and blowing agent are then extruded at a temperature less than the
melting temperature of the majority of the aliphatic polyamide material and
less
than the decomposition temperature of the blowing agent to form an extrudate.
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The extrudate is then calendered to form a backing sheet. The backing sheet is
then adhered to the floor covering. The process also comprises the step of
heating the backing sheet to a temperature above the decomposition
temperature of the blowing agent, thereby causing the backing sheet to expand
to form a cushioned backing layer.
Other useful products including, but not limited to, building materials, car
parking stops and highway guardrail offset blocks are also provided. The
process
for producing these useful products, which are made from the densified
recycled
and reclaimed scrap materials, may include the use of a profile extrusion
process
and linear low-density polyethylene (LLDPE) or similar material. The extruded
waste material is fed through an extrusion die, which can contain the shape of
the desired article of manufacture to further define the final shape of the
article of
manufacture, is cooled by means of a continuous chilled water bath and upon
exiting the chilled water bath is cut while in motion to the desired length or
width.
Further mechanical processing specific to the final article of manufacture,
such
as planing, sawing, or drilling may be desired.
Brief Description of the Drawings
Some of the objects and advantages of the invention having been stated,
other objects will appear as the description proceeds when taken in
conjunction
with the accompanying drawings in which:
Figure 1 is a diagrammatic view of the process for making products in
accordance with the present invention.
Figure 2 is a diagrammatic view of a process for making products in
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accordance with the present invention by profile extrusion.
Figure 3 is a front, plan view of a die exit plate of the profile extruder
shown in Figure 2.
Figure 4a and 4b are side and front views of a sizing die used in the
profile extruder shown in Figure 2.
Figure 5 is a perspective view of an industrial block flooring in accordance
with the present invention.
Figure 6 is a perspective view of a parking stop in accordance with the
present invention.
Figure 7 is an enlarged cross-sectional view of a floor covering in
accordance with the present invention.
Figure 8 is an enlarged cross-sectional view of an alternate embodiment
of a floor covering in accordance with the present invention.
Figure 9 is an enlarged cross-sectional view of a second alternate
embodiment of a floor covering in accordance with the present invention.
Figure 10 is an enlarged cross-sectional view of a floor covering having a
cushioned secondary backing in accordance with the present invention.
Detailed Description of the Preferred Embodiment
While the present invention will be described more fully hereinafter with
reference to the accompanying drawings in which particular embodiments of the
invention are shown, it is to be understood at the outset that persons of
skill in
the appropriate arts may modify the invention here described while still
achieving
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the favorable results of this invention. Accordingly, the description which
follows
is to be understood as being a broad, teaching disclosure directed to persons
of
skill in the appropriate arts, and not as limiting upon the present invention.
A preferred form of the process is illustrated in Figure 1 wherein waste
polymeric material (scrap) 15, such as carpet remnants or carpet tiles, is
delivered to a guillotine chopper 20. The waste polymeric material 15
typically
comprises a wide variety of thermoplastic material generated during the
manufacture of floor coverings and generated in the disposal of used floor
coverings. Typical thermoplastic materials that may be present include
aliphatic
polyamides, polyolefins (e.g., polyethylene and polypropylene), polymers based
on vinyl monomers (e.g., vinyl chloride and vinyl esters such as vinyl
acetate),
polymers based on acrylic monomers (e.g., acrylic acid, methyl acrylic acid,
esters of these acids, and acrylonitrile), other thermoplastic polymers, and
blends
and copolymers thereof. The aliphatic polyamides that are present in the
material
15 can range in the amount of about 0 to 40 percent of the total amount of
material 15, but are normally approximately 12% of the total amount of
material
15. The aliphatic polyamides add strength (stability) to the resulting
recycled
material 66, such that the aliphatic polyamides increase the tear resistance
and
breaking strength and decrease the elongation and shrinkage of the resulting
recycled material 66. The term "aliphatic polyamide polymer" used herein and
throughout the specification may include, but is not limited to, long-chain
polymeric or copolymeric amide which has recurring amide groups as an integral
part of the main polymer or copolymer chain, which may be in the form of a
fiber.
Examples of aliphatic polyamides can include nylon 6 or poly (c~-caprolactam);
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nylon 66 or poly (hexamethylenedia mine-adipic acid) amide; poly .
(hexamethylenediamine-sebacic acid) amide or nylon 610; and the like. The
mixture that is used to produce the resulting recycled material 66 is designed
to
produce an article of manufacture that has flexible properties such that the
article
can be rolled or unrolled at room temperature and at colder temperatures.
The guillotine chopper 20 is any conventional guillotine chopper that
coarsely chops the waste polymer material into 3/4 to 1 inch in width
portions. A
suitable guillotine chopper is Model CT-60 available from Pieret, Inc. The
. chopped mixture 26a, which is free of most metal, is transported, for
example, via
conveyer belts 25 and 26 to a granulator 40, which grinds the one inch
portions
. into fragments at least an order of magnitude smaller than the original size
of
waste polymeric material. Typically this is about 3/8 inch and smaller. A
suitable
granulaior is Model 24-1 available from Cumberland Company.
The granulated mixture 40a is transported to a densifier 41. The densifier
41 is designed to heat, melt, and form or compact solid smaller pieces of the
granulated mixture 40a such chat the extruder 50 can produce a more uniform
blend of the resulting recycled material 66. The densifier 41 increases the
density
of the granulated mixture 40a to form densified material 42 that will be fed
to the
exlruder 50. With the use of the densifier 41, such as a
PlaslcompactomPeNetizer T'~'
Model No. CV50, manufactured by HERBOLD ZERKLEINERUNGSTECHNIK
GmbH, the density of the granulated material 40a is increased such that the
output of the extruder 50 is increased from approximately 1,000 Ibs. per hour
to
approximately 4,000 to 6,000 Ibs. per hour. The densifier 41 blends the
granulated material 40a, which can be in the form of a fluffy, fibrous
material with
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solid polymeric particles to form the densified material 42 which is in the
shape of
semi-uniform pellets. The densifier 41 has an approximate volume densification
ratio of 2:1 (original granulated material to densified material volume).
Optionally, if a finer material is required, the densified, pelletized
material
42 can be sent via a conveyor to a cryogenic grinder (not shown) that uses
liquid.
nitrogen to freeze and grind the densified, pelletized material 42 to foml a
hard
cryogenically ground material that is fed into the extruder 50. The ground
material is made up of particles that are typically on the order of 0.01-0.20
inches in diameter. These particles may be screened to remove particles lager
than a desired limit.
Cryogenic grinding may also be used as an alternative to or as a
precedent step to the densification of the granulated material 40a. Under this
alternative, the granulated mixture 40a can be sent via a conveyor 26 to a
cryogenic grinder (not shown). The cryogenically ground material can then be
sent either to the densitier 41 or to the extruder 50.
The densified material 42 and/or the cryogenically ground material 42A is
transported via air in a conduit 43 to a Gaylord loading station 45 and/or to
a silo
46. If desired, fines, dust and/or fibers can be removed and separated from
the
densified material 42 and/or the cryogenically ground material;
The densified material 42 and/or the cryogenically ground material is
then conveyed to the extruder hopper 55 which feeds the extruder 50.
Additional
recycled material such as granulated waste PVC may be added to the waste
polymeric material 42 or the cryogenically ground material in the hopper.
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A suitable extruder is Model 2DS-K 57M32 or ZSK-170 M 1750 10 G, both
available from Werner & Pfleiderer. The extruder 50 includes a control means
53
(e.g., a motor gearbox) and a feeder 55 that is connected to the silo 46 and
to
additional feeding tubes for accepting different materials. A metal detection
station, such as a magnet, is located at the entrance of the feeder 55.
Control
means 53 is provided to insure that the extruder 50 and feeder 55 act
cooperatively to maintain a constant feed condition throughout the conveying
zone to a zone comprising one or more kneading zones (not shown). The fed
materials then pass through an extruder barrel 57 including a degassing or a
vacuum zone and then through a pumping zone which forces the materials
through a die 58. The pumping zone functions to develop sufficient throughput
without creating intolerable back pressures and torque in the preceding zones
or
on the thrust bearings of the extruder 50. The extruder is operated at a
temperature selected to not exceed the temperature at which the largest
portion
of polymer based vinyl monomers and blends and copolymers thereof of the
waste material decompose, which is about 200°C (390°F to
400°F). The extruder
is also preferably operated at a temperature less than the melting temperature
of
the majority of the aliphatic polyamide material. As discussed in more detail
below, if the fed materials include a blowing agent for foaming the resulting
article, the extruder must be operated at a temperature below the
decomposition
temperature of the blowing agent. Typically, the extruder 50 is operated such
that
a melt temperature of 300°F to 390°F is maintained as the
extruded blend 59
exits the die 58. The extruded blend 59 can pass through a metal detector 60
before being transported to a calender 61, where it is formed into a sheet of
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recycled material 66 and then cooled at a cooling station 63. The cooled
recycled
material 66 may be accumulated by an accumulator 65 and then rolled up at a
collection station 67. The resulting recycled material 66 can be calendered to
form a backing layer for a floor covering that is flexible and can be rolled
or easily
handled or moved. Alternatively, a sheet may be formed using a sheet die
attachment in combination wish the extruder 59 or a second extruder. If a
sheet
die is used, it is preferred that the recycled materiel 66 be formed from
powdered
waste polymeric material that has been cryoground in order to avoid clogging
of
the die.
Accordingly, exemplary articles of manufacture include secondary
backings for floor coverings, components of other building material, such as
sound barriers, roofing materials and the like.
The recycled material 66 can be reduced in density (i.e., foamed) by the
addition of a chemical blowing agent, which when decomposed expands to form
gas-filled cavities within the material. The reduction in density results in a
foamed
recycled material having cushioning properties. Such properties are are
particularly advantageous when the foamed material is used as a backing
layer for a floor covering.
The resulting recycled material with cushion properties 66A is produced by
adding a chemical blowing agent to the recycled material 66 and other
additives
into the feeder 55. Feeder 55 supplies these materials to the extruder 50..,A
pelletized azodicarbonamide blowing agent such as Blo-Foam PMA 50 TM from Rit
Chem Company, Inc. can be used. The pellet is composed of 50 % azo blowing
agent (ADC 1200 grade) and 50 % PVC and is therefore 50 % active. The
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average particle size of the blowing agent is 5 microns, which correlates to
the
average diameter of the circular particle. The optimum particle size is
approximately 3 to 4 microns. The decomposition temperature of the active azo
ingredient, ADC 1200 is approximately 195° to 220° C
(383° to 428° F), however,
the effective decomposition temperature of the activated azodicarbonamide of
the pellet ranges from 175° to 185° C (347° to
365° F). Other blowing agents
having decomposition temperatures as low as 325°F may be used as long
as the
extrusion temperature is lower than the decomposition temperature. The gas
volume resulting from decomposition of the azodicarbonamide is in the range of
85 to 115 mUgram of azodicarbonamide. The blowing agent decomposes (i.e., is
activated) at its corresponding decomposition temperature and releases gas.
This release of gas produces a cell or gas pocket (referenced in Figurel0 as
256) in the recycled material having cushion properties in the form of
a.bubble,
cavity or void. Blowing agents can be added in liquid, powder or pellet form.
Typical addition levels range from approximately 0.1 to 5% (wtlwt) - based on
the percent "active" azodicarbonamide. The addition level is preferably in a
range
of approximately 0.5-2.0% (or 0.25-1.0% active).
Other alternate chemical blowing agents include, but are not limi#ed to, p-
toluene sulfonyl semicarbizide or p,p oxybis benzene sulfonyl hydrazide(OBSH).
The activation or decomposition race of the blowing agent can be altered
through
the use of an activator. Suitable activators for azodicarbonamide blowing
agents
include, but are not limited to, transition metal salts, particularly those of
feed,
cadmium and zinc or organometallic complexes such as zinc oxides, zinc
stearate, or barium stearate. Although dependent on the composition and
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activation characteristics of the blowing agent, activators aqe typically
added at
approximately a 1 to 1 ratio of activator to blowing agent.
Prior to or during extrusion, it is necessary to thoroughly mix the blowing
agent and/or activator with the recycled material 66 or reduced density
recycled
S material and other additives in order to obtain a uniform dispersion. A
uniform
mixture is essential to ensure cells or gas pockets exist uniformly in the
sheet.
This in turn ensures that he resulting sheet with be of uniform thickness. In
order
to achieve a fine cell structure, it is preferred that fibrous material be
removed
from the recycled material or reduced to non-fibrous or powder-like
proportions.
Fibrous material may be removed from waste polymeric material through an
elutriation process. It has been found, however, that a fine cell structure
can be
produced by cryogenic grinding of the densified palletized ma#erial to form a
fine
powder, which is then mixed with the blowing agent in the feeder 55.
The melt temperature of the reduced density recycled material ~in the
1S extruder 50 is kept below the decomposition temperature of the blowing
agent so
Thai the blowing agent in the reduced density recycled material will not be
activated during extrusion. After extrusion, the reduced density recycled
material
66A, is conveyed by conveyor to the calender 61 where it is formed into a
sheet.
Once a sheet is formed, the sheet is heated above the decomposition
20 temperature of the blowing agent causing it to release gas and form ceNs or
gas
pockets 256 in the reduced density recycled material 66A. The cells 256 reduce
the density and increase the thickness of the sheet. For example, at a blowing
agent level of approximately 0.5% (0.25% active), a sheet made from reduced
density recycled material 66A can reach a thickness after activation that is
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approximately 2 to.3 times its original thickness. A sheet produced from
reduced
density recycled material is reduced in density from approximately 85 Ibslft3
at 35 mils thickness to approximately 27 Ibs/ft3 at 110 mils thickness. An
ideal
density for a commercial carpet backing ranges from approximately 18 Ibs/ft3
to
28 Ibs/ft3~ The density chosen within this range is application specific. For
example, in applications where considerable rolling traffic is prevalent a
higher
density in the upper end of the range is preferred.
In order for a carpet backing to be considered a cushion, it must be
comprised of "cells'° or air spaces 256. The cells 256 of the cushion
must be'
intentional, individual, non-connecting and gas tight for the structure of the
cushion to be considered closed-cell. Additionally, the cells 256 must be
incorporated into a flexible polymer matrix. This structure provides a
cushioning
effect by allowing the carpet backing to compress under an external load and
recover when the load is removed.
A reduced density recycled material can also be achieved by the
incorporation of other materials having a lower-density than recycled material
66
into the extruder 50 through the feeder 55. The incorporation of a recycled
or,
waste material having a lower density would be desired due to the positive
environmental impact. This may include, but is not limited to, materials
having a
lower density than the recycled material 66 such as ethylene vinyl acetate,
polyethylene, wood flour and the shells of crustaceans having a chitinous or
calcareous and chitinous exoskeleton. Lower density materials may include
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those that contain air such as coarsely ground thermoset foam, or hollow
microspheres.
Another method that can be used to form a low density material involves
the:ase of direct gas injection during the extrusion of the recycled material
66
or reduced density recycled material. In this method supercritical carbon
dioxide
or other similar working fluid is injected into the material and allowed to
expand
immediately after extrusion to form a foamed sheet material.
After a sheet is formed from the recycled material 66 or the reduced
density recycled material, it can be fused by lamination to a carpet product
to form a backing layer. In the case of the reduced density material, this can
be accomplished either before or after the sheet has been foamed through heat
activation of the blowing agent. If the sheet is to be adhered to the carpet
after
foaming, the seep of activating the blowing agent may be accomplished by
heating the calendered sheet to the decomposition temperature. Alternatively,
the sheet can be healed to the decomposition temperature substantially
simultaneously with the calendering operation. Similarly, if the sheet is
formed
using a sheet die attachment on an extruder, the extruder can be operated at a
temperature chat causes the blowing agent to be activated during extrusion.
After
expansion is complete, the sheet is heat laminated to the back of the carpet
product. As an alternative to an adhered backing, a foamed sheet formed from
the recycled material 66 or the reduced density recycled material could also
so
be used as a separate pad or cushion for placement underneath carpeting.
The above methods can provide a suitable floor covering backing material.
It has been found, however, that under certain conditions, it is difficult to
maintain
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the dimensional stability of a free-standing foamed sheet during the expansion
process. Therefore, in one embodiment of the present invention, a sheet formed
from recycled material 66 or reduced density recycled material and a blowing
agent is adhered to a carpet back prior to activation of the blowing agent:
This is
accomplished by heating one side of the sheet to a temperature sufficient to
adhere the sheet to the carpet but insufficient to activate the blowing agent.
Alternately, the sheet may be adhered to the carpet back immediately after
forming as for example when a sheet die/extruder combination is used. The
carpet with the sheet backing is then placed on a belt with the carpet face
facing
downward. It is then fed into an oven to heat the sheet backing to a
temperature
1p sufficient to decompose and activate the blowing agent. The backed carpet
then
passes out of the oven for cooling. Because the recycled backing sheet is
adhered to the carpet, it tends to retain its dimensional stability during
expansion
and through the cooling process.
Referring now to Figures 2 and 3, an alternate embodiment of the process
15 illustrated in Figure 1 is shown wherein the extruder 50 has an extruder
die 100
with a die exit place 105 that has an opening wish a rectangular shape 106,
but
can have different shapes, including, but not be limited to, a trapezoid
shape, a
square shape, circular or conical shapes, etc. The densified material 42
and/or
the cryogenically ground material 42A is conveyed to the extruder 50 and exits
20 the exlruder 50 through the die exit plate 105 as an extruded blend 110
that has
acquired the shape 106 of the die exit plate 105. The extruded blend 110 is
pushed info a sizing die 115, shown in Figures 4a and 4b, located witJ~in a
sizing
cooling section 120 that may be connected to a water cooling section 130. The
sizing die 115 is positioned adjacent to the die exit plale 105, but allows
the
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extruded blend 110 to air cool prior to entering the sizing die 115. The
sizing die
115 has an opening 125 with the same shape 106 as the opening in the die exit
plate 105, and has an extension 126 that is approximately 18 inches long that
also has the same shape 106 of the die exit plate 105.
The extruded blend 110 travels through the sizing cooling section 120 into
the water cooling section 130, which is approximately 60 feet long. At the far
end
of the water cooling section 130 is a conveyor pulling motor 135 that grips
and
pulls the extruded blend 110 through the water cooling section 130. Chilled
water
is circulated through the sizing cooling section 120 and the water cooling
section
130. The chilled water enters the sizing cooling section 120 at approximately
38°F and exits the water cooling section 130 at approximately
62°F. The water is
then sent to a heat exchanger unit (not shown) for recooling the water before
the
water is recycled back into the sizing cooling section 120 and the water
cooling
section 130. The conveyor pulling motor 135 grips and pulls the extruded
material 110 through the water cooling section 130 at a rate of approximately
4.8
feet per minute. The extruded material 110 enters the sizing cooling section
120
at a temperature of approximately 330°F to 340° F, and exits the
water cooling
section 130 at a temperature of approximately 180°F or less. By cooling
the
extruded blend 110 to 180°F or less, the extruded blend 110 is able to
maintain
the shape 106 acquired from the die exit plate 105 and the sizing die 115.
The conveyor pulling motor 135 pulls and conveys the extruded blend 110
through the use of conveyors 136 into a rotating circular saw 141 that cuts
the
extruded blend 110 into pieces 150 which are approximately six feet in length
that can be used as a building material. The pieces 150 can be conveyed
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through conveyors 151 to a planar saw 152 to adjust the acquired shape of the
extruded blend 110, The pieces 150 are then conveyed to a stacking station 160
for stacking the pieces 150. The pieces 150 can then be cut into smaller
pieces
155, as shown in Figure 5, for use as building material that when connected
together can form, for example, a block floor covering 156.
Alternatively, the pieces 150 can have holes 159 drilled into the ends of
the pieces 150 at the drill press station (not shown) to form parking stop
strips
165, as shown in Figure 6, prior to being stacked. The pieces 150 can still be
used as parking stop strips 165 without having any drilled holes 158.
Referring now to Figures 1 and 7, articles that can be made from the
process described and illustrated in Figure 1, include a floor covering 170
(e.g. a
pile carpet or a mat). As shown in Figure 7, tufted pile yams 180 are looped
through a primary backing 182, and extend upwardly therefrom. The backcoating
181 is an adhesive coating that fixes the pile yarns 180 in place in the
primary
backing 182. A secondary backing 184, which is made from the recycled material
66 or the reduced density recycled material, is then adhered to the primary
backing 182. This may be done using the backcoating 181 or another adhesive
or by heal lamination. The primary backing 182 may be formed by weaving
synthetic fibers, such as polypropylene, polyethylene, nylon, or polyester,
for
example, or may be a nonwoven construction utilizing one or more of these
thermoplastic polymers. As is conventional, the. pile yarns 180 may be cut to
form
cut pile iufils as illustrated in Figure 7, or may form loops as shown in
Figure 8.
The backcoating 181 may be comprised of any suitable polymer
compound. Typically, the backcoaiing 1'81 is comprised of either a polymer
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CA 02340555 2005-03-29
emulsion polymerization product or a polymer plastisol compound. The
backcoating 181 is cured on the textile material by heating or drying or in
any
way reacting the backcoating 181 to cure, cross link or fuse it to the textile
material. An exemplary emulsion polymerization product includes a
polyvinylidene chloride or ethylene vinyl copolymer wNh at least one acrylic
monomer. Standard acrylic monomers include, for example, acrylic acid, methyl
acrylic acid, esters of these acids, or acrylonitrile. Alternatively, the
backcoating
181 may comprise conventional thermoplastic polymers which are applied to the
carpet by hot melt coating techniques known in the art.
To bond the secondary backing 184 to the backcoating 181, additional
heat is applied to both the secondary backing 184 and the backcoating 181
before pressing the two layers together. The secondary backing 184 is
contacted
with the backcoating 181. The temperature is sufficient to partially melt the
contacting surfaces of both the backcoating 181 and the secondary backing 184
IS thereby bonding the secondary backing 184 to the backcoating 181 forming an
integral structure, such as described in U.S. Patent Nos. 3,560,284 and
3,695,987 to Wisotzky, As discussed above, the secondary backing 184 can be
made from the reduced density resulting recycled material, which provided for
cushioned properties. If the reduced density secondary backing layer includes
a
flowing agent, the secondary backing layer may be adhered to the backcoating
either before or after it has been expanded by activation of the blowing
agent.
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A second embodiment of a floor covering utilizing the resulting recycled
material 66 is shown in Figure 8. A floor covering 190, which may be formed in
the shape of a tile or a mat, is shown having looped pile yarns 180 tufted or
.
looped through a primary backing 191 and extending upwardly therefrom. As is
conventional, the pile yarns 180 may be curio form cut pile tufts as
illustrated in
Figure 7. A backcoating 192, which is an adhesive coating, is used to fix the
pile
yarns 180 in place in the primary. backing 191. A stabilizing reinforcement
layer
195 and a fusion coat or plastisol adhesive layer 196 are located between the
backcoating 192 and a secondary backing 194. The~econdary backing 194 can
be made from the resulting recycled material 66 or the reduced density
recycled
material. The fusion coat or plastisol adhesive layer 196 and the secondary
backing 194 are heated before being pressed together to form the floor
covering
190. If a reduced density secondary' backing layer including a blowing agent
is
used, the secondary backing layer may be adhered-either before or after 'tt
has
been expanded by activation of the blowing agent. Adhered onto the bottom
surface of the secondary backing 194 is an aqueous, pressure sensitive
oleophobic adhesive layer 197, as set forth in U.S. Patent No. 4,849,267 for a
Foam Backed Carpet with Adhesive Surface and Method of Installing Same;
The '267 Patent is owned by the assignee of the present invention. It will be
understood by those having ordinary skill in the art that other adhesives may
also
be used. A releasable cover or liner 198 may be removable attached to the
adhesive layer 197.
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Additionally,, some carpet remnants, especially carpet tiles contain
fiberglass reinforcement material. In recycling the .carpet remnants and/or
carpet
tiles as scraps 15, the fiberglass, through the above-mentioned chopping and
grinding process, is reduced to small pieces. The round, short, cylindrical
pieces
of fiberglass may plate out onto or be located on the surface allowing the
possibility for release when handling the resulting recycled material 66. The
oleophobic adhesive layer 197 encapsulates any fiberglass fibers on the
surface
of the resulting recycled material 66, now the secondary backing 194.
The oleophobic adhesive layer 197 also accelerates equilibrium of
moisture regain in the hydrophillic components of the secondary backing 194.
The extrusion process and/or the heating process results in a near bone dry
condition of the hydrophillic components. The oleophobic adhesive layer 197
reintroduces moisture info the resulting recycled material 66, which is now
the
secondary backing 194. The forced drying of the oleophobic adhesive layer '197
once applied to the secondary backing 194 additionally improves the resulting
stability of the floor covering 190. The use of an oleophobic adhesive layer
197
and releasable cover 198 can be applied to the secondary backing 184 of the
floor covering 170. Also, the secondary backing t 94 can be made from the
recycled material that has a reduced density layer which provided for
cushioning properties. The floor coverings 170 and 190 pan be formed in the
shape of a tile.
Another embodiment of a floor covering utili2ing the resulting recycled
material 66 would be similar to chat shown in Figure 8, except that the layer
1 96
could be made directly from the resulting recycled material 66. This makes
layer
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196 now become the secondary backing layer and eliminates the need to have
the backing layer 7 94. As previously discussed, the oleophobic adhesive layer
197, which would be placed against the layer 196, accelerates the equilibrium
of
moisture gain in the hydrophillic components of the resulting recycled
material
66, which now is the layer 196.
Referring now to Figure 9; a woven floor covering 220, which may be in
the shape of a tile, is shown. The woven floor covering 220 is shown
having a woven carpet Layer 225, a resin composition 230, a backing layer 235,
and optionally a releasable oleophobic adhesive layer 236 with a releasable
cover 237. The woven carpet layer 225 is formed by weaving warp yarns 238 and
weft yarns 239 to provide a decorative face surface. The backing layer 235 can
be made from the resulting recycling niaterial 66. The oleophobic adhesive
layer
236, as discussed above, is used to encapsulate fiberglass on the surface of
the
backing layer 235 and accelerate the equilibrium of moisture gain in the
hydrophillic components of the resulting recycled material 66, which is now
the
backing layer 235.
Referring now to Figure 10, a cushioned floor covering 245 .is shown. The
20 cushioned floor covering may be in the shape of a tile or a rolled carpet.
The
cushioned floor covering 245 is shown having pile yarns 260 that are looped
through a primary backing 250 and extending upwardly therefrom. The pile yarns
260 are then cut. Alternatively, the pile yarns 260 do not have to be cut, as
shown in Figure 8. A backcoating 252, which is an adhesive coating, fixes the
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pile yarns 260 in the primary backing 250. A secondary backing 255, which is
made from the reduced density resulting recycled material 66A and provides for
cushioning properties, is adhered to the primary backing 250 using the
backcoating 252. If the recycled material 66A includes a blowing agent, the
secondary backing may be adhered either before or after expansion due to
activation of the blowing agent. The secondary backing 255 has air pockets or
cavities 256 formed within the backing layer. An oleophobic adhesive layer 265
and a releasable cover 270 may be adhered to the secondary backing 255.
Summary
The above-described processes and the articles utilizing the same provide
for the recycling of waste polymeric material that can include from 0 to 40%
aliphatic polyamide material and vinyl monomer and copolymer components. The
waste material is granulated and densified wherein the chopped mixture is
formed into pelletized fragments for extruding at a melt temperature range of
approximately 300° to 380°F. Articles, such as floor coverings,
can be made
utilizing the recycled article of manufacture. The waste material may be mixed
with a blowing agent prior to extrusion. Upon activation of the blowing agent,
the
material expands to provide a lower density article.
It is to be understood that while certain forms of this invention have been
illustrated and described, the invention is not limited thereto, except
insofar as
such limitations are included in the following claims.
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