U.S. patent application number 16/409599 was filed with the patent office on 2019-08-29 for systems for manufacturing bulked continuous filament from recycled pet.
The applicant listed for this patent is Aladdin Manufacturing Corporation. Invention is credited to Thomas R. Clark.
Application Number | 20190263022 16/409599 |
Document ID | / |
Family ID | 66170408 |
Filed Date | 2019-08-29 |
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United States Patent
Application |
20190263022 |
Kind Code |
A1 |
Clark; Thomas R. |
August 29, 2019 |
SYSTEMS FOR MANUFACTURING BULKED CONTINUOUS FILAMENT FROM RECYCLED
PET
Abstract
A system for manufacturing bulked continuous carpet filament
that is adapted for providing a polymer melt and dividing the
polymer melt into a plurality of streams (e.g., at least six or
eight streams) to increase a surface area of the polymer melt. The
plurality of streams is then exposed to a pressure that is below
approximately 5 millibars. The streams are then recombined into a
single polymer stream and formed into bulked continuous carpet
filament. In various embodiments, an extruder, such as a
multi-screw extruder, is used to divide the polymer melt into the
plurality of streams.
Inventors: |
Clark; Thomas R.;
(Chattanooga, TN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Aladdin Manufacturing Corporation |
Calhoun |
GA |
US |
|
|
Family ID: |
66170408 |
Appl. No.: |
16/409599 |
Filed: |
May 10, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16220733 |
Dec 14, 2018 |
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16409599 |
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15419955 |
Jan 30, 2017 |
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16220733 |
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15396143 |
Dec 30, 2016 |
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15419955 |
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13892713 |
May 13, 2013 |
9550338 |
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15396143 |
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13721955 |
Dec 20, 2012 |
8597553 |
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13892713 |
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61654016 |
May 31, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29B 2013/005 20130101;
B29K 2105/26 20130101; B29B 2017/0244 20130101; B29C 48/43
20190201; B29K 2067/003 20130101; B29B 13/02 20130101; B29B
2017/0289 20130101; B29L 2031/7158 20130101; B29B 2017/0268
20130101; B29C 48/05 20190201; B29C 48/70 20190201; B29C 2948/922
20190201; B29B 2017/0484 20130101; B29C 48/144 20190201; B29C
48/2552 20190201; B29B 2017/0279 20130101; C08J 11/06 20130101;
B29B 2017/0241 20130101; B29C 2948/92695 20190201; B29B 2017/0015
20130101; B29C 48/92 20190201; Y02W 30/62 20150501; B29B 2013/002
20130101; B29C 48/385 20190201; B29C 2948/92876 20190201; H05K
999/99 20130101; B29C 48/255 20190201; B29C 48/44 20190201; B01D
29/0095 20130101; D01F 6/62 20130101; B29C 48/425 20190201; B29C
48/766 20190201; B29B 17/00 20130101; B29B 17/0042 20130101; B29B
17/02 20130101; B29B 2017/0224 20130101; B29K 2105/0067 20130101;
B29B 13/06 20130101; B29C 48/435 20190201; C08J 11/04 20130101;
D01D 5/00 20130101; B29C 2948/92514 20190201; B29C 2948/92752
20190201; B29D 99/0078 20130101; D01D 1/103 20130101; B29C 48/277
20190201; B29C 48/38 20190201; C08J 2367/02 20130101; Y02P 20/143
20151101; D01D 5/08 20130101; B29C 48/40 20190201; D01D 1/106
20130101; D10B 2503/04 20130101; B29B 17/0412 20130101 |
International
Class: |
B29B 17/02 20060101
B29B017/02; B29D 99/00 20060101 B29D099/00; C08J 11/06 20060101
C08J011/06; D01D 5/00 20060101 D01D005/00; C08J 11/04 20060101
C08J011/04; D01D 1/10 20060101 D01D001/10; D01F 6/62 20060101
D01F006/62; B29B 17/00 20060101 B29B017/00; B01D 29/00 20060101
B01D029/00; D01D 5/08 20060101 D01D005/08; B29C 48/255 20060101
B29C048/255; B29C 48/43 20060101 B29C048/43; B29C 48/70 20060101
B29C048/70; B29C 48/44 20060101 B29C048/44; B29C 48/76 20060101
B29C048/76; B29C 48/435 20060101 B29C048/435; B29C 48/425 20060101
B29C048/425; B29C 48/385 20060101 B29C048/385; B29C 48/14 20060101
B29C048/14; B29C 48/92 20060101 B29C048/92; B29C 48/38 20060101
B29C048/38; B29C 48/05 20060101 B29C048/05 |
Claims
1. A manufacturing system for manufacturing bulked continuous
carpet filament, the system comprising: a first extruder section
that is adapted to advance a polymer melt towards a second extruder
section, the second extruder section being adapted to separate the
polymer melt into at least eight streams of polymer melt so that
the at least eight streams of polymer melt pass through an interior
portion of a chamber; a pressure regulation system that is adapted
to maintain a chamber pressure within the interior portion of the
chamber between about 0 millibars and about 5 millibars as the at
least eight streams of polymer melt pass through the interior
portion of the chamber; a third extruder section that is adapted to
receive the at least eight streams of polymer after the at least
eight streams of polymer have been exposed to the chamber pressure
of between about 0 millibars and about 5 millibars and to convey
polymer from the at least eight streams of polymer relative to the
chamber; and a spinning machine that is adapted to receive the
polymer that has been conveyed by the third extruder section and to
form the conveyed polymer into bulked continuous carpet
filament.
2. The manufacturing system of claim 1, wherein the second extruder
section comprises the chamber.
3. The manufacturing system of claim 1, wherein the system is
adapted so that the at least eight streams of polymer melt are
simultaneously exposed to the chamber pressure of between about 0
millibars and about 5 millibars as the at least eight streams of
polymer melt pass through the interior portion of the chamber.
4. The manufacturing system of claim 3, wherein the system is
adapted to facilitate advancement of each of the eight streams of
polymer melt as they pass through the interior portion of the
chamber and are simultaneously exposed to the chamber pressure of
between about 0 millibars and about 5 millibars.
5. The manufacturing system of claim 1, wherein the pressure
regulation system is adapted to maintain a chamber pressure within
the interior portion of the chamber below about 1.5 millibars as
the at least eight streams of polymer melt pass through the
interior portion of the chamber.
6. The manufacturing system of claim 1, wherein the pressure
regulation system is adapted to maintain a chamber pressure within
the interior portion of the chamber between about 0.5 millibars and
5 millibars as the at least eight streams of polymer melt pass
through the interior portion of the chamber.
7. The manufacturing system of claim 1, wherein the pressure
regulation system is adapted to maintain a chamber pressure within
the interior portion of the chamber between about 0.5 millibars and
1.2 millibars as the at least eight streams of polymer melt pass
through the interior portion of the chamber.
8. The manufacturing system of claim 1, wherein the third extruder
section comprises a single screw extruder.
9. The manufacturing system of claim 1, wherein the third extruder
section is adapted to form the at least eight streams of polymer
into a single polymer stream.
10. The manufacturing system of claim 9, wherein the manufacturing
system is adapted for: measuring an intrinsic viscosity of the
single polymer stream; and in response to determining that the
intrinsic viscosity of the single polymer stream is below a
predetermined level, substantially automatically lowering the
chamber pressure in order to achieve a higher intrinsic viscosity
within the polymer melt.
11. The manufacturing system of claim 1, wherein the polymer melt
is derived, at least in part, from polyethylene terephthalate (PET)
flakes that are derived from recycled PET.
12. The manufacturing system of claim 11, wherein the recycled PET
comprises post-consumer, recycled PET bottles.
13. The manufacturing system of claim 1, wherein: the first
extruder section is a first extrusion means; the second extruder
section is a second extrusion means; the pressure regulation system
is a pressure regulation means; the third extruder section is a
third extrusion means; and the spinning machine is a spinning
means.
14. The manufacturing system of claim 1, wherein the at least eight
streams of polymer melt travel along respective paths that are
substantially parallel to each other as the at least eight streams
pass through the interior portion of the chamber and are exposed to
the chamber pressure within the interior portion of the chamber of
between about 0 millibars and about 5 millibars.
15. A manufacturing system for manufacturing bulked continuous
carpet filament, the system comprising: a chamber defining an
interior portion; a vacuum system that is adapted to maintain a
chamber pressure within the interior portion of the chamber below
about 5 millibars as at least eight streams of polymer melt pass
through the interior portion of the chamber along substantially
parallel paths, thereby exposing at least a respective portion of
each of the at least eight streams to the chamber pressure of below
about 5 millibars; an extruder that is positioned to receive
polymer from the at least eight streams after the at least eight
streams pass through the interior portion of the chamber as the
interior portion of the chamber is maintained below about 5
millibars, and to advance the received polymer toward a spinning
machine that is adapted to form the received polymer into bulked
continuous carpet filament; and the spinning machine that is
adapted to form the received polymer into bulked continuous carpet
filament.
16. The manufacturing system of claim 15, wherein the system is
adapted so that the at least eight streams of polymer melt are
simultaneously exposed to a pressure within the chamber of below
about 1.5 millibars as the at least eight streams of polymer melt
pass through the interior portion of the chamber.
17. The manufacturing system of claim 15, wherein the system is
adapted so that the at least eight streams of polymer melt are
simultaneously exposed to a pressure within the chamber of between
about 0.5 millibars and about 1.2 millibars as the at least eight
streams of polymer melt pass through the interior portion of the
chamber.
18. The manufacturing system of claim 15, wherein the extruder is
adapted to form the at least eight streams of polymer into a single
polymer stream after the respective portions of each of the at
least eight streams of polymer melt are exposed to the chamber
pressure of below about 5 millibars.
19. The manufacturing system of claim 18, wherein the manufacturing
system is adapted for: measuring an intrinsic viscosity of the
single polymer stream; and in response to determining that the
intrinsic viscosity of the single polymer stream is below a
predetermined level, substantially automatically lowering the
chamber pressure in order to achieve a higher intrinsic viscosity
within the polymer melt.
20. The manufacturing system of claim 15, wherein the manufacturing
system is adapted to form the at least eight streams of polymer
into a single polymer stream after the respective portions of each
of the at least eight streams of polymer melt are exposed to the
chamber pressure of below about 5 millibars; determining an
intrinsic viscosity of the single polymer stream; and in response
to determining that the intrinsic viscosity of the single polymer
stream is below a predetermined level, lowering the chamber
pressure in a substantially automated manner via a
computer-controlled feedback control loop.
21. A system for manufacturing bulked continuous carpet filament,
the system comprising: an extruder adapted to receive a plurality
of polymer flakes and melt the plurality of polymer flakes to
create a polymer melt; a chamber adapted to receive the polymer
melt from the extruder and separate the polymer melt into at least
eight streams at an entry portion of the chamber and to recombine
the at least eight streams into a single polymer stream at an exit
portion of the chamber; a pressure regulation system adapted to
reduce a chamber pressure within the chamber to between about 0
millibars and about 5 millibars; and a spinning machine adapted to
receive the single polymer stream from the chamber and to form the
single polymer stream into bulked continuous carpet filament.
22. The system of claim 21, wherein the plurality of polymer flakes
comprises colored PET flakes derived from recycled PET bottles.
23. The system of claim 21, further comprising: a color management
system adapted to determine a color of the single polymer stream
and substantially automatically adjust an amount of one or more
color concentrates added to the plurality of polymer flakes or the
single polymer stream based at least in part on the determined
color of the single polymer stream.
24. The system of claim 21, further comprising an intrinsic
viscosity management system adapted to determine an intrinsic
viscosity of the single polymer stream, and in response to
determining the viscosity, adjusting the chamber pressure until the
single polymer stream comprises a desired intrinsic viscosity.
25. A manufacturing system for manufacturing carpet filament, the
system comprising: (A) a washing section that is adapted for
washing a group of polymer flakes, the group of flakes comprising a
first plurality of flakes that consist essentially of PET and a
second plurality of flakes that do not consist essentially of PET;
(B) a purifying section that is adapted for: (1) after the group of
polymer flakes is washed by the washing section: (a) scanning the
washed group of polymer flakes to identify the first plurality of
flakes; and (b) separating the first plurality of flakes from the
second plurality of flakes; (2) melting the first plurality of
flakes to produce a polymer melt; (3) extruding the polymer melt
into at least 6 different streams of polymer melt; (4) removing one
or more volatile organic compounds from the at least 6 different
streams of polymer melt by simultaneously exposing at least a
respective portion of each of the at least 6 different streams of
polymer melt to a pressure of below about 5 millibars; and (C) a
bulked continuous filament forming section that is adapted for,
after the at least 6 different streams of polymer melt are exposed
to a pressure of below about 5 millibars, forming polymer from the
at least 6 different streams of polymer melt into bulked continuous
carpet filament.
26. The manufacturing system of claim 25, wherein removing one or
more volatile organic compounds from the at least 6 different
streams of polymer melt comprises exposing at least a respective
portion of each of the at least 6 different streams of polymer melt
to a pressure of between about 0.5 millibars and about 1.2
millibars.
27. The manufacturing system of claim 25, wherein removing one or
more volatile organic compounds from the at least 6 different
streams of polymer melt comprises exposing at least a respective
portion of each of the at least 6 different streams of polymer melt
to a pressure of between about 0 millibars and about 1.5
millibars.
28. The manufacturing system of claim 25, wherein the manufacturing
system is further adapted to combine the at least 6 different
extrusion streams into a single stream of polymer melt before
forming polymer from the at least 6 extrusion streams into bulked
continuous carpet filament.
29. The manufacturing system of claim 25, wherein the system
comprises a multi-screw extruder for extruding the polymer melt
into the at least 6 different streams of polymer melt.
30. The manufacturing system of claim 25, wherein the manufacturing
system is adapted for: forming the at least six streams of polymer
into a single polymer stream after the respective portions of each
of the at least six streams of polymer melt are exposed to the
pressure of below about 5 millibars; determining an intrinsic
viscosity of the single polymer stream; and in response to
determining that the intrinsic viscosity of the single polymer
stream is below a predetermined level, lowering the pressure in the
chamber in a substantially automated manner via a
computer-controlled feedback control loop.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 16/220,733, filed Dec. 14, 2018, entitled "Methods For
Manufacturing Bulked Continuous Filament from Recycled PET", which
is a continuation-in-part of U.S. patent application Ser. No.
15/419,955, filed Jan. 30, 2017, entitled "Methods For
Manufacturing Bulked Continuous Filament from Colored Recycled
PET", which is a continuation-in-part of U.S. patent application
Ser. No. 15/396,143, filed Dec. 30, 2016, entitled "Systems And
Methods For Manufacturing Bulked Continuous Filament", which is a
continuation of U.S. patent application Ser. No. 13/892,713, filed
May 13, 2013, entitled "Systems and Methods for Manufacturing
Bulked Continuous Filament", now U.S. Pat. No. 9,550,338, issued
Jan. 24, 2017, which is a divisional of U.S. patent application
Ser. No. 13/721,955, filed Dec. 20, 2012, entitled "Systems and
Methods for Manufacturing Bulked Continuous Filament", now U.S.
Pat. No. 8,597,553, issued Dec. 3, 2013, which claimed priority
from U.S. Provisional Patent Application No. 61/654,016, filed May
31, 2012, entitled "Systems and Methods for Manufacturing Bulked
Continuous Fiber," all of which are hereby incorporated herein by
reference in their entirety.
BACKGROUND
[0002] Because pure virgin PET polymer is more expensive than
recycled PET polymer, and because of the environmental benefits
associated with using recycled polymer, it would be desirable to be
able to produce bulked continuous carpet filament, and other items,
from 100% recycled PET polymer (e.g., PET polymer from
post-consumer PET bottles).
SUMMARY
[0003] A manufacturing system for manufacturing bulked continuous
carpet filament, according to various embodiments, comprises: (1) a
first extruder section that is adapted to advance a polymer melt
towards a second extruder section, the second extruder section
being adapted to separate the polymer melt into at least eight
streams of polymer melt so that the at least eight streams of
polymer melt pass through an interior portion of a chamber; (2) a
pressure regulation system that is adapted to maintain a chamber
pressure within the interior portion of the chamber between about 0
millibars and about 5 millibars as the at least eight streams of
polymer melt pass through the interior portion of the chamber; (3)
a third extruder section that is adapted to receive the at least
eight streams of polymer after the at least eight streams of
polymer have been exposed to the chamber pressure of between about
0 millibars and about 5 millibars and to convey polymer from the at
least eight streams of polymer relative to the chamber; and (4) a
spinning machine that is adapted to receive the polymer that has
been conveyed by the third extruder section and to form the
conveyed polymer into bulked continuous carpet filament.
[0004] A manufacturing system for manufacturing bulked continuous
carpet filament, according to various embodiments, comprises: (1) a
chamber defining an interior portion; (2) a vacuum system that is
adapted to maintain a chamber pressure within the interior portion
of the chamber below about 5 millibars as at least eight streams of
polymer melt pass through the interior portion of the chamber along
substantially parallel paths, thereby exposing at least a
respective portion of each of the at least eight streams to the
chamber pressure of below about 5 millibars; (3) an extruder that
is positioned to receive polymer from the at least eight streams
after the at least eight streams pass through the interior portion
of the chamber as the interior portion of the chamber is maintained
below about 5 millibars, and to advance the received polymer toward
a spinning machine that is adapted to form the received polymer
into bulked continuous carpet filament; and (4) the spinning
machine that is adapted to form the received polymer into bulked
continuous carpet filament.
[0005] A system for manufacturing bulked continuous carpet
filament, according to various embodiments, comprises: (1) an
extruder adapted to receive a plurality of polymer flakes and melt
the plurality of polymer flakes to create a polymer melt; (2) a
chamber adapted to receive the polymer melt from the extruder and
separate the polymer melt into at least eight streams at an entry
portion of the chamber and to recombine the at least eight streams
into a single polymer stream at an exit portion of the chamber; (3)
a pressure regulation system adapted to reduce a chamber pressure
within the chamber to between about 0 millibars and about 5
millibars; and (4) a spinning machine adapted to receive the single
polymer stream from the chamber and to form the single polymer
stream into bulked continuous carpet filament.
[0006] A manufacturing system for manufacturing carpet filament,
according to various embodiments, comprises: (A) a washing section
that is adapted for washing a group of polymer flakes, the group of
flakes comprising a first plurality of flakes that consist
essentially of PET and a second plurality of flakes that do not
consist essentially of PET; (B) a purifying section that is adapted
for: (1) after the group of polymer flakes is washed by the washing
section: (a) scanning the washed group of polymer flakes to
identify the first plurality of flakes; and (b) separating the
first plurality of flakes from the second plurality of flakes; (2)
melting the first plurality of flakes to produce a polymer melt;
(3) extruding the polymer melt into at least 6 different streams of
polymer melt; and (4) removing one or more volatile organic
compounds from the at least 6 different streams of polymer melt by
simultaneously exposing at least a respective portion of each of
the at least 6 different streams of polymer melt to a pressure of
below about 5 millibars; and (C) a bulked continuous filament
forming section that is adapted for, after the at least 6 different
streams of polymer melt are exposed to a pressure of below about 5
millibars, forming polymer from the at least 6 different streams of
polymer melt into bulked continuous carpet filament.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Having described various embodiments in general terms,
reference will now be made to the accompanying drawings, which are
not necessarily drawn to scale, and wherein:
[0008] FIG. 1 depicts a process flow, according to a particular
embodiment, for manufacturing bulked continuous carpet
filament.
[0009] FIG. 2 is a perspective view of an exemplary MRS extruder
that is suitable for use in the process of FIG. 1.
[0010] FIG. 3 is a cross-sectional view of an exemplary MRS section
of the MRS extruder of FIG. 2.
[0011] FIG. 4 depicts a process flow depicting the flow of polymer
through an MRS extruder and filtration system according to a
particular embodiment.
[0012] FIG. 5 is a high-level flow chart of a method, according to
various embodiments, of manufacturing bulked continuous carpet
filament.
DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS
[0013] Various embodiments will now be described in greater detail.
It should be understood that the invention may be embodied in many
different forms and should not be construed as limited to the
embodiments set forth herein. Rather, these embodiments are
provided so that this disclosure will be thorough and complete, and
will fully convey the scope of the invention to those skilled in
the art. Like numbers refer to like elements throughout.
I. Overview
[0014] New processes for making fiber from recycled polymer (e.g.,
recycled PET polymer) are described below. In various embodiments,
this new process: (1) is more effective than earlier processes in
removing contaminates and water from the recycled polymer; and/or
(2) does not require the polymer to be melted and cooled as many
times as in earlier processes. In at least one embodiment, the
improved process results in a recycled PET polymer having a polymer
quality that is high enough that the PET polymer may be used in
producing bulked continuous carpet filament from 100% recycled PET
content (e.g., 100% from PET obtained from previously used PET
bottles). In particular embodiments, the recycled PET polymer has
an intrinsic viscosity of at least about 0.79 dL/g (e.g., of
between about 0.79 dL/g and about 1.00 dL/g).
II. More Detailed Discussion
[0015] A BCF (bulked continuous filament) manufacturing process,
according to a particular embodiment, may comprise three steps: (1)
preparing flakes of PET polymer from post-consumer bottles for use
in the process; (2) passing the flakes through an extruder that
melts the flakes and purifies the resulting PET polymer; and (3)
feeding the purified polymer into a spinning machine that turns the
polymer into filament for use in manufacturing carpets. These three
steps are described in greater detail below.
Step 1: Preparing Flakes of PET Polymer from Post-Consumer
Bottles
[0016] In a particular embodiment, the step of preparing flakes of
PET polymer from post-consumer bottles comprises: (A) sorting
post-consumer PET bottles and grinding the bottles into flakes; (B)
washing the flakes; and (C) identifying and removing any impurities
or impure flakes.
[0017] A. Sorting Post-Consumer PET Bottles and Grinding the
Bottles into Flakes
[0018] In particular embodiments, bales of clear and mixed colored
recycled post-consumer (e.g., "curbside") PET bottles (or other
containers) obtained from various recycling facilities make-up the
post-consumer PET containers for use in the process. In other
embodiments, the source of the post-consumer PET containers may be
returned `deposit` bottles (e.g., PET bottles whose price includes
a deposit that is returned to a customer when the customer returns
the bottle after consuming the bottle's contents). The curbside or
returned "post-consumer" or "recycled" containers may contain a
small level of non-PET contaminates. The contaminants in the
containers may include, for example, non-PET polymeric contaminants
(e.g., PVC, PLA, PP, PE, PS, PA, etc.), metal (e.g., ferrous and
non-ferrous metal), paper, cardboard, sand, glass or other unwanted
materials that may find their way into the collection of recycled
PET. The non-PET contaminants may be removed from the desired PET
components, for example, through one or more of the various
processes described below.
[0019] In particular embodiments, smaller components and debris
(e.g., components and debris greater than 2 inches in size) are
removed from the whole bottles via a rotating trammel. Various
metal removal magnets and eddy current systems may be incorporated
into the process to remove any metal contaminants. Near Infra-Red
optical sorting equipment such as the NRT Multi Sort IR machine
from Bulk Handling Systems Company of Eugene, Oreg., or the Spyder
IR machine from National Recovery Technologies of Nashville, Tenn.,
may be utilized to remove any loose polymeric contaminants that may
be mixed in with the PET flakes (e.g., PVC, PLA, PP, PE, PS, and
PA). Additionally, automated X-ray sorting equipment such as a
VINYLCYCLE machine from National Recovery Technologies of
Nashville, Tenn. may be utilized to remove remaining PVC
contaminants.
[0020] In particular embodiments, a binary segregation of the clear
materials from the colored materials is achieved using automated
color sorting equipment equipped with a camera detection system
(e.g., a Multisort ES machine from National Recovery Technologies
of Nashville, Tenn.). In various embodiments, manual sorters are
stationed at various points on the line to remove contaminants not
removed by the sorter and any colored bottles. In particular
embodiments, the sorted material is taken through a granulation
step (e.g., using a 50B Granulator machine from Cumberland
Engineering Corporation of New Berlin, Wis.) to size reduce (e.g.,
grind) the bottles down to a size of less than one half of an inch.
In various embodiments, the bottle labels are removed from the
resultant "dirty flake" (e.g., the PET flakes formed during the
granulation step) via an air separation system prior to entering
the wash process.
[0021] B. Washing the Flakes
[0022] In particular embodiments, the "dirty flake" is then mixed
into a series of wash tanks. As part of the wash process, in
various embodiments, an aqueous density separation is utilized to
separate any olefin bottle caps (which may, for example, be present
in the "dirty flake" as remnants from recycled PET bottles) from
the higher specific gravity PET flakes. In particular embodiments,
the flakes are washed in a heated caustic bath to about 190 degrees
Fahrenheit. In particular embodiments, the caustic bath is
maintained at a concentration of between about 0.6% and about 1.2%
sodium hydroxide. In various embodiments, soap surfactants as well
as defoaming agents are added to the caustic bath, for example, to
further increase the separation and cleaning of the flakes. A
double rinse system then washes the caustic from the flakes.
[0023] In various embodiments, the flake is centrifugally dewatered
and then dried with hot air to at least substantially remove any
surface moisture. The resultant "clean flake" is then processed
through an electrostatic separation system (e.g., an electrostatic
separator from Carpco, Inc. of Jacksonville, Fla.) and a flake
metal detection system (e.g., an MSS Metal Sorting System) to
further remove any metal contaminants that remain in the flake. In
particular embodiments, an air separation step removes any
remaining label from the clean flake. In various embodiments, the
flake is then taken through a flake color sorting step (e.g., using
an OPTIMIX machine from TSM Control Systems of Dundalk, Ireland) to
remove any remaining color contaminants remaining in the flake. In
various embodiments, an electro-optical flake sorter based at least
in part on Raman technology (e.g., a Powersort 200 from Unisensor
Sensorsysteme GmbH of Karlsruhe, Germany) performs the final
polymer separation to remove any non-PET polymers remaining in the
flake. This step may also further remove any remaining metal
contaminants and color contaminants.
[0024] In various embodiments, the combination of these steps
delivers substantially clean (e.g., clean) PET bottle flake
comprising less than about 50 parts per million PVC (e.g., 25 ppm
PVC) and less than about 15 parts per million metals for use in the
downstream extrusion process described below.
[0025] C. Identifying and Removing Impurities and Impure Flakes
[0026] In particular embodiments, after the flakes are washed, they
are fed down a conveyor and scanned with a high-speed laser system
300. In various embodiments, particular lasers that make up the
high-speed laser system 300 are configured to detect the presence
of particular contaminates (e.g., PVC or Aluminum). Flakes that are
identified as not consisting essentially of PET may be blown from
the main stream of flakes with air jets. In various embodiments,
the resulting level of non-PET flakes is less than 25 ppm.
[0027] In various embodiments, the system is adapted to ensure that
the PET polymer being processed into filament is substantially free
of water (e.g., entirely free of water). In a particular
embodiment, the flakes are placed into a pre-conditioner for
between about 20 and about 40 minutes (e.g., about 30 minutes)
during which the pre-conditioner blows the surface water off of the
flakes. In particular embodiments, interstitial water remains
within the flakes. In various embodiments, these "wet" flakes
(e.g., flakes comprising interstitial water) may then be fed into
an extruder (e.g., as described in Step 2 below), which includes a
vacuum setup designed to remove--among other things--the
interstitial water that remains present in the flakes following the
quick-drying process described above.
[0028] Step 2: Using an Extrusion System to Melt and Purify PET
Flakes
[0029] In particular embodiments, an extruder is used to turn the
wet flakes described above into a molten recycled PET polymer and
to perform a number of purification processes to prepare the
polymer to be turned into BCF for carpet. As noted above, in
various embodiments, after STEP 1 is complete, the recycled PET
polymer flakes are wet (e.g., surface water is substantially
removed (e.g., fully removed) from the flakes, but interstitial
water remains in the flakes). In particular embodiments, these wet
flakes are fed into a Multiple Rotating Screw ("MRS") extruder 400.
In other embodiments, the wet flakes are fed into any other
suitable extruder (e.g., a twin screw extruder, a multiple screw
extruder, a planetary extruder, or any other suitable extrusion
system). An exemplary MRS Extruder 400 is shown in FIGS. 2 and 3. A
particular example of such an MRS extruder is described in U.S.
Published Patent Application 2005/0047267, entitled "Extruder for
Producing Molten Plastic Materials", which was published on Mar. 3,
2005, and which is hereby incorporated herein by reference.
[0030] As may be understood from this figure, in particular
embodiments, the MRS extruder includes a first single-screw
extruder section 410 for feeding material into an MRS section 420
and a second single-screw extruder section 440 for transporting
material away from the MRS section.
[0031] In various embodiments, the wet flakes are fed directly into
the MRS extruder 400 substantially immediately (e.g., immediately)
following the washing step described above (e.g., without drying
the flakes or allowing the flakes to dry). In particular
embodiments, a system that feeds the wet flakes directly into the
MRS Extruder 400 substantially immediately (e.g., immediately)
following the washing step described above may consume about 20%
less energy than a system that substantially fully pre-dries the
flakes before extrusion (e.g., a system that pre-dries the flakes
by passing hot air over the wet flakes for a prolonged period of
time). In various embodiments, a system that feeds the wet flakes
directly into the MRS Extruder 400 substantially immediately (e.g.,
immediately) following the washing step described above avoids the
need to wait a period of time (e.g., up to eight hours) generally
required to fully dry the flakes (e.g., remove all of the surface
and interstitial water from the flakes).
[0032] FIG. 4 depicts a process flow that illustrates the various
processes performed by the MRS Extruder 400 in a particular
embodiment. In the embodiment shown in this figure, the wet flakes
are first fed through the MRS extruder's first single-screw
extruder section 410, which may, for example, generate sufficient
heat (e.g., via shearing) to at least substantially melt (e.g.,
melt) the wet flakes.
[0033] In the embodiment shown in this figure, the system is
further configured to add a Solution Dye Color Concentrate 415 to
the flakes (e.g., wet flakes) before feeding the flakes into the
first singe-screw extruder section 410. In particular embodiments,
the Solution Dye Color Concentrate 415 may include any suitable
color concentrate, which may, for example, result in a particular
color of polymer fiber following extrusion. In particular
embodiments, the color concentrate may comprise pelletized color
concentrate as well as a carrier resin which may, for example, bind
the colorant to the polymer. In various embodiments, adding color
concentrate to the flakes prior to extrusion may result in polymer
filament that is at least partially impregnated (e.g., impregnated)
with a color pigment. In particular embodiments, carpet produced
from solution dyed filament may be highly resistant to color loss
through fading from sunlight, ozone, harsh cleaning agents such as
bleach, or other factors.
[0034] In various embodiments, the system is configured to adjust
an amount of Solution Dye Color Concentrate 415 to add to the
flakes prior to feeding the flakes thought the first single-screw
extruder section 410. In particular embodiments, the system is
configured to add between about two percent and about three percent
color concentrate by mass to the polymer flake. In other
embodiments, the system is configured to between about zero percent
and about three percent color concentrate by mass. In still other
embodiments, the system is configured to add up to about six
percent color concentrate by mass to the polymer flake prior to
extrusion. In some embodiments, the system is configured to add
between about one percent and three percent color concentrate by
mass to the polymer flake. In still other embodiments, the system
is configured to add any suitable ratio of color concentrate to
polymer flake in order to achieve a particular color of molten
polymer (and ultimately polymer fiber) following extrusion.
[0035] Although in the embodiment shown in this figure, the
Solution Dye Color Concentrate 415 is depicted as added to the
polymer flake prior to feeding the flake through the first
single-screw extruder section 410, it should be understood that in
other embodiments, the Solution Dye Color Concentrate 15 may be
added during any other suitable phase of the process described in
this document. For example, in various embodiments, the system is
configured to add the Solution Dye Color Concentrate 415 following
extrusion of the polymer flake by the first single-screw extruder
section 410 but prior to feeding the resultant polymer melt through
the extruder's MRS section 420 discussed below. In still other
embodiments, the system may add the Solution Dye Color Concentrate
415 after the flake has passed through the MRS extruder's MRS
section 420 prior to passing the polymer melt through the second
single screw section 440 discussed below. In still other
embodiments, they system may add the Solution dye Color Concentrate
415 while the flakes and/or polymer melt are being extruded in the
first single-screw extruder section 410, MRS Section 420, second
single screw section 440, or at any other suitable phase of the
process. In still other embodiments, the system may add the
Solution Dye Color Concentrate 415 during one or more (e.g., a
plurality) of the phases of the process described herein (e.g., the
system may add some Solution Dye Color Concentrate 415 to the
polymer flake prior to passing the flake through the single-screw
extruder section 410 and some additional solution Dye Color
Concentrate 415 following extrusion through the MRS Section
420).
[0036] Following the addition of the color concentrate and
extrusion by the first single-screw extruder section 410, the
resultant polymer melt (e.g., comprising the melted flakes and
color concentrate), in various embodiments, is then fed into the
extruder's MRS section 420, in which the extruder separates the
melt flow into a plurality of different streams (e.g., 4, 6, 8, or
more streams) through a plurality of open chambers. FIG. 3 shows a
detailed cutaway view of an MRS Section 420 according to a
particular embodiment. In particular embodiments, such as the
embodiment shown in this figure, the MRS Section 420 separates the
melt flow into eight different streams, which are subsequently fed
through eight satellite screws 425A-H. As may be understood from
FIG. 2, in particular embodiments, these satellite screws are
substantially parallel (e.g., parallel) to one other and to a
primary screw axis of the MRS Machine 400.
[0037] In the MRS section 420, in various embodiments, the
satellite screws 425A-H may, for example, rotate faster than (e.g.,
about four times faster than) in previous systems. As shown in FIG.
3, in particular embodiments: (1) the satellite screws 425A-H are
arranged within a single screw drum 428 that is mounted to rotate
about its central axis; and (2) the satellite screws 425A-H are
configured to rotate in a direction that is opposite to the
direction in which the single screw drum rotates 428. In various
other embodiments, the satellite screws 425A-H and the single screw
drum 428 rotate in the same direction. In particular embodiments,
the rotation of the satellite screws 425A-H is driven by a ring
gear. Also, in various embodiments, the single screw drum 428
rotates about four times faster than each individual satellite
screw 425A-H. In certain embodiments, the satellite screws 425A-H
rotate at substantially similar (e.g., the same) speeds.
[0038] In various embodiments, as may be understood from FIG. 4,
the satellite screws 425A-H are housed within respective extruder
barrels, which may, for example be about 30% open to the outer
chamber of the MRS section 420. In particular embodiments, the
rotation of the satellite screws 425A-H and single screw drum 428
increases the surface exchange of the polymer melt (e.g., exposes
more surface area of the melted polymer to the open chamber than in
previous systems). In various embodiments, the MRS section 420
creates a melt surface area that is, for example, between about
twenty and about thirty times greater than the melt surface area
created by a co-rotating twin screw extruder. In a particular
embodiment, the MRS section 420 creates a melt surface area that
is, for example, about twenty five times greater than the melt
surface area created by a co-rotating twin screw extruder.
[0039] In various embodiments, the MRS extruder's MRS Section 420
is fitted with a Vacuum Pump 430 that is attached to a vacuum
attachment portion 422 of the MRS section 420 so that the Vacuum
Pump 430 is in communication with the interior of the MRS section
via a suitable opening 424 in the MRS section's housing. In still
other embodiments, the MRS Section 420 is fitted with a series of
Vacuum Pumps. In particular embodiments, the Vacuum Pump 430 is
configured to reduce the pressure within the interior of the MRS
Section 420 to a pressure that is between about 0.5 millibars and
about 5 millibars. In particular embodiments, the Vacuum Pump 430
is configured to reduce the pressure in the MRS Section 420 to less
than about 1.5 millibars (e.g., about 1 millibar or less). The
low-pressure vacuum created by the Vacuum Pump 430 in the MRS
Section 420 may remove, for example: (1) volatile organics present
in the melted polymer as the melted polymer passes through the MRS
Section 420; and/or (2) at least a portion of any interstitial
water that was present in the wet flakes when the wet flakes
entered the MRS Extruder 400. In various embodiments, the
low-pressure vacuum removes substantially all (e.g., all) of the
water and contaminants from the polymer stream.
[0040] In a particular example, the Vacuum Pump 430 comprises three
mechanical lobe vacuum pumps (e.g., arranged in series) to reduce
the pressure in the chamber to a suitable level (e.g., to a
pressure of about 1.0 millibar). In other embodiments, rather than
the three mechanical lobe vacuum pump arrangement discussed above,
the Vacuum Pump 430 includes a jet vacuum pump fit to the MRS
extruder. In various embodiments, the jet vacuum pump is configured
to achieve about 1 millibar of pressure in the interior of the MRS
section 420 and about the same results described above regarding a
resulting intrinsic viscosity of the polymer melt. In various
embodiments, using a jet vacuum pump can be advantageous because
jet vacuum pumps are steam powered and therefore substantially
self-cleaning (e.g., self-cleaning), thereby reducing the
maintenance required in comparison to mechanical lobe pumps (which
may, for example, require repeated cleaning due to volatiles coming
off and condensing on the lobes of the pump). In a particular
embodiment, the Vacuum Pump 430 is a jet vacuum pump is made by
Arpuma GmbH of Bergheim, Germany.
[0041] In particular embodiments, after the molten polymer is run
through the multi-stream MRS Section 420, the streams of molten
polymer are recombined and flow into the MRS extruder's second
single screw section 440. In various embodiments, the single stream
of molten polymer is next run through a filtration system 450 that
includes at least one filter. In a particular embodiment, the
filtration system 450 includes two levels of filtration (e.g., a 40
micron screen filter followed by a 25 micron screen filter).
Although, in various embodiments, water and volatile organic
impurities are removed during the vacuum process as discussed
above, particulate contaminates such as, for example, aluminum
particles, sand, dirt, and other contaminants may remain in the
polymer melt. Thus, this filtration step may be advantageous in
removing particulate contaminates (e.g., particulate contaminates
that were not removed in the MRS Section 420).
[0042] In particular embodiments, a viscosity sensor 460 (see FIG.
4) is used to sense the melt viscosity of the molten polymer stream
following its passage through the filtration system 450. In various
embodiments, the viscosity sensor 460, measures the melt viscosity
of the stream, for example, by measuring the stream's pressure drop
across a known area. In particular embodiments, in response to
measuring an intrinsic viscosity of the stream that is below a
predetermined level (e.g., below about 0.8 g/dL), the system may:
(1) discard the portion of the stream with low intrinsic viscosity;
and/or (2) lower the pressure in the MRS Section 420 in order to
achieve a higher intrinsic viscosity in the polymer melt. In
particular embodiments, decreasing the pressure in the MRS Section
420 is executed in a substantially automated manner (e.g.,
automatically) using the viscosity sensor in a computer-controlled
feedback control loop with the vacuum section 430.
[0043] In particular embodiments, removing the water and
contaminates from the polymer improves the intrinsic viscosity of
the recycled PET polymer by allowing polymer chains in the polymer
to reconnect and extend the chain length. In particular
embodiments, following its passage through the MRS Section 420 with
its attached Vacuum Pump 430, the recycled polymer melt has an
intrinsic viscosity of at least about 0.79 dL/g (e.g., of between
about 0.79 dL/g and about 1.00 dL/g). In particular embodiments,
passage through the low pressure MRS Section 420 purifies the
recycled polymer melt (e.g., by removing the contaminants and
interstitial water) and makes the recycled polymer substantially
structurally similar to (e.g., structurally the same as) pure
virgin PET polymer. In particular embodiments, the water removed by
the vacuum includes both water from the wash water used to clean
the recycled PET bottles as described above, as well as from
unreacted water generated by the melting of the PET polymer in the
single screw heater 410 (e.g., interstitial water). In particular
embodiments, the majority of water present in the polymer is wash
water, but some percentage may be unreacted water.
[0044] Returning to FIG. 4, in particular embodiments, a Color
Sensor 470 is used to determine a color of the resultant polymer
melt. In various embodiments, the Color Sensor 470 comprises one or
more spectrographs configured to separate light shone through the
polymer melt into a frequency spectrum to determine the color of
the polymer melt. In still other embodiments, the Color Sensor 470
comprises one or more cameras or other suitable imaging devices
configured to determine a color of the resultant polymer melt. In
particular embodiments, in response to determining that the color
of the polymer melt is a color other than a desired color (e.g.,
the polymer melt is lighter than desired, darker than desired, a
color other than the desired color, etc.) the system may: (1)
discard the portion of the stream with the incorrect color; and/or
(2) adjust an amount of Solution Dye Color Concentrate 415 that is
added to the flake and/or the polymer melt upstream in order to
adjust a color of the resultant polymer melt. In particular
embodiments, adjusting the amount of Solution Dye Color Concentrate
415 is executed in a substantially automated manner (e.g.,
automatically) using the Color Sensor 470 in a computer-controlled
feedback control loop.
[0045] In particular embodiments, the resulting polymer is a
recycled PET polymer (e.g., obtained 100% from post-consumer PET
products, such as PET bottles or containers) having a polymer
quality that is suitable for use in producing PET carpet filament
using substantially only (e.g., only) PET from recycled PET
products.
Step 3: Purified PET Polymer Fed into Spinning Machine to be Turned
into Carpet Yarn
[0046] In particular embodiments, after the recycled PET polymer
has been extruded and purified by the above-described extrusion
process, the resulting molten recycled PET polymer is fed directly
into a BCF (or "spinning") machine 500 that is configured to turn
the molten polymer into bulked continuous filament. For example, in
various embodiments, the output of the MRS extruder 400 is
connected substantially directly (e.g., directly) to the input of
the spinning machine 500 so that molten polymer from the extruder
is fed directly into the spinning machine 500. This process may be
advantageous because molten polymer may, in certain embodiments,
not need to be cooled into pellets after extrusion (as it would
need to be if the recycled polymer were being mixed with virgin PET
polymer). In particular embodiments, not cooling the recycled
molten polymer into pellets serves to avoid potential chain
scission in the polymer that might lower the polymer's intrinsic
viscosity.
[0047] In particular embodiments, the spinning machine 500 extrudes
molten polymer through small holes in a spinneret in order to
produce carpet yarn filament from the polymer. In particular
embodiments, the molten recycled PET polymer cools after leaving
the spinneret. The carpet yarn is then taken up by rollers and
ultimately turned into filaments that are used to produce carpet.
In various embodiments, the carpet yarn produced by the spinning
machine 500 may have a tenacity between about 3 gram-force per unit
denier (gf/den) and about 9 gf/den. In particular embodiments, the
resulting carpet yarn has a tenacity of at least about 3
gf/den.
[0048] In particular embodiments, the spinning machine 500 used in
the process described above is the Sytec One spinning machine
manufactured by Oerlika Neumag of Neumuenster, Germany. The Sytec
One machine may be especially adapted for hard-to-run fibers, such
as nylon or solution-dyed fibers, where the filaments are prone to
breakage during processing. In various embodiments, the Sytec One
machine keeps the runs downstream of the spinneret as straight as
possible, uses only one threadline, and is designed to be quick to
rethread when there are filament breaks.
[0049] Although the example described above describes using the
Sytec One spinning machine to produce carpet yarn filament from the
polymer, it should be understood that any other suitable spinning
machine may be used. Such spinning machines may include, for
example, any suitable one-threadline or three-threadline spinning
machine made by Oerlika Neumag of Neumuenster, Germany or any other
company.
[0050] In various embodiments, the improved strength of the
recycled PET polymer generated using the process above allows it to
be run at higher speeds through the spinning machine 500 than would
be possible using pure virgin PET polymer. This may allow for
higher processing speeds than are possible when using virgin PET
polymer.
Summary of Exemplary Process
[0051] FIG. 5 provides a high-level summary of various embodiments
of the method of manufacturing bulked continuous filament described
above. As shown in the figure, the method begins at Step 602, where
recycled PET bottles are ground into a group of flakes. Next, at
Step 604, the group of flakes is washed to remove contaminants from
the flakes' respective outer surfaces. Next, at Step 606, the group
of flakes is scanned (e.g., using one or more of the methods
discussed above) to identify impurities, including impure flakes.
These impurities, and impure flakes, are then removed from the
group of flakes.
[0052] Next, at Step 608, the group of flakes is passed through an
MRS extruder while maintaining the pressure within an MRS portion
of the extruder below about 1.5 millibars. At Step 610, the
resulting polymer melt is passed through at least one filter having
a micron rating of less than about 50 microns. Finally, at Step
612, the recycled polymer is formed into bulked continuous carpet
filament, which may be used in producing carpet. The method then
ends at Step 614.
ALTERNATIVE EMBODIMENTS
[0053] In particular embodiments, the system may comprise
alternative components or perform alternative processes in order to
produce substantially continuous BCF from 100% recycled PET, or
other recycled polymer. Exemplary alternatives are discussed
below.
[0054] Non-MRS Extrusion System
[0055] In particular embodiments, the process may utilize a polymer
flow extrusion system other than the MRS Extruder described above.
The alternative extrusion system may include for example, a twin
screw extruder, a multiple screw extruder, a planetary extruder, or
any other suitable extrusion system. In a particular embodiment,
the process may include a plurality of any combination of any
suitable conical screw extruders (e.g., four twin screw extruders,
three multiple screw extruders, etc.).
[0056] Making Carpet Yarn from 100% Recycled Carpet
[0057] In particular embodiments, the process described above may
be adapted for processing and preparing old carpet (or any other
suitable post-consumer product) to produce new carpet yarn
comprising 100% recycled carpet. In such embodiments, the process
begins by grinding and washing recycled carpet rather than recycled
PET bottles. In various embodiments where old carpet is converted
into new carpet yarn comprising 100% recycled carpet, the process
may comprise additional steps to remove additional materials or
impurities that may be present in recycled carpet that may not be
present in recycled PET bottles (e.g., carpet backing, adhesive,
etc.).
[0058] Other Sources of Recycled PET
[0059] In various embodiments, the process described above is
adapted for processing recycled PET from any suitable source (e.g.,
sources other than recycled bottles or carpet) to produce new
carpet yarn comprising 100% recycled PET.
The Use of a Crystallizer as Part of BCF Process
[0060] In various embodiments, the process for producing recycled
BCF may further include a crystallizing step that utilizes one or
more PET crystallizers. In particular embodiments, the system is
configured to perform the crystallization step on the ground flakes
prior to running the flakes through the one or more extruders
(e.g., single screw extruder, MRS extruder, etc.). In particular
embodiments, the PET crystallizer comprises a housing, a hopper
screw (e.g., an auger) disposed at least partially within the
housing, a stirring apparatus, one or more heating elements, and
one or more blowers.
[0061] Hopper Screw
[0062] In particular embodiments, the hopper screw comprises any
suitable screw conveyor (e.g., such as an Archimedes' screw) for
moving liquid or granular materials (e.g., such as PET flakes). In
various embodiments, the hopper screw comprises a substantially
cylindrical shaft and a helical screw blade disposed along at least
a portion of the cylindrical shaft. In particular embodiments, the
substantially cylindrical shaft is configured to rotate the screw
blade, causing that hopper screw to move material (e.g., the PET
flakes) along the cylindrical shaft and into the crystallizer
housing. In other embodiments, the hopper screw comprises any other
suitable screw conveyer such as, for example, a shaftless spiral.
In embodiments in which the hopper screw comprises a shaftless
spiral, the shaftless spiral may be substantially fixed at one end
and free at the other end and configured to be driven at the fixed
end. In various embodiments, the hopper screw is disposed at least
partially within the crystallizer housing.
[0063] In various embodiments, the hopper screw is configured to
feed PET flakes into the crystallizer. In various embodiments, the
PET crystallizer is configured to feed the PET flakes into the
crystallizer using the hopper screw relatively slowly.
[0064] One or More Heating Elements
[0065] In various embodiments, the crystallizer comprises one or
more heating elements for raising a temperature within the
crystallizer. In particular embodiments, the one or more heating
elements comprise one or more electric heating elements, one or
more gas-fired heating elements, or any other suitable heating
elements. In some embodiments, the one or more heating elements may
be substantially electrically powered. In various embodiments, the
one or more heating elements comprise one or more infra-red heating
elements. In other embodiments, the one or more heating elements
may utilize natural gas such, for example, propane. In particular
embodiments, the one or more heating elements are configured to
raise a temperature within the crystallizer to between about 100
degrees Fahrenheit and about 180 degrees Fahrenheit. In still other
embodiments, the one or more heating elements are configured to
raise a temperature within the crystallizer to between about 100
degrees Celsius and 180 degrees Celsius. In some embodiments, the
one or more heating elements are configured to maintain a
temperature within the crystallizer that is substantially about a
maximum crystallization temperature of PET. In particular
embodiments, the maximum crystallization temperature of PET is
between about 140 degrees Celsius and about 230 degrees
Celsius.
[0066] One or More Blowers
[0067] In various embodiments, the crystallizer further comprises
one or more blowers configured to blow air over the flakes as the
flakes passes through the crystallizer. In particular embodiments,
the one or more blowers comprise any suitable blowers for moving
air substantially across a surface area of the flakes as the flakes
pass through the crystallizer. For example, in some embodiments,
the one or more blowers comprise one or more suitable fans or other
suitable mechanisms for moving air. In various embodiments, the one
or more blowers are configured to blow air that has been at least
partially heated by the one or more heating elements. In particular
embodiments, the one or more blowers are configured to blow air
having a temperature of at least about 140 degree Fahrenheit. In
another particular embodiments, the one or more blowers are
configured to blow air having a temperature of at least about 140
degree Celsius. In other embodiments, the one or more blowers are
configured to maintain the temperature in the crystallizer between
about 140 degrees Fahrenheit and about 180 degrees Fahrenheit. In
some embodiments, the one or more blowers are configured to blow
hot air from a bottom portion of the crystallizer and draw air from
an upper portion of the crystallizer.
[0068] Stirring Apparatus
[0069] In various embodiments, the crystallizer comprises a
stirring apparatus that comprises any suitable apparatus for
stirring the PET flakes while the PET flakes are passing through
the crystallizer. In various embodiments, the stirring apparatus
may be operated, for example, by any suitable gear motor. In a
particular embodiment, the stirring apparatus comprises a suitable
rod or other suitable mechanism mounted to rotate, or otherwise
stir the PET flakes as the PET flakes are passing through the
crystallizer. In other embodiments, the stirring apparatus may
comprise any suitable tumbler, which may, for example, comprise a
drum mounted to rotate via the gear motor such that the PET flakes
are at least partially stirred and/or agitated while the PET flakes
are within the drum. In still other embodiments, the stirring
apparatus comprises one or more screws and/or augers configured to
rotate and stir the PET flakes. In particular embodiments, the
stirring apparatus comprises the hopper screw.
[0070] As may be understood from this disclosure, the stirring
apparatus is configured to agitate or stir the PET flakes as the
one or more blowers blow air heated by the one or more heating
elements across the PET flakes. In particular embodiments, the
stirring apparatus is configured to at least partially reduce
agglomeration (e.g., sticking or clumping of the flake) while the
flake is at least partially crystallizing in the crystallizer.
[0071] In particular embodiments, the crystallizer at least
partially dries the surface of the PET flakes. In various
embodiments, the PET crystallizer is configured to reduce a
moisture content of the PET flakes to about 50 ppm. In other
embodiments the PET crystallizer is configured to reduce a moisture
content of the PET flakes to between about 30 and about 50 ppm.
[0072] In various embodiments, the use of drier flakes may enable
the system to run the flakes through the MRS extruder more slowly,
which may allow for higher pressure within the MRS extruder during
extrusion (e.g., may enable the system to maintain a higher
pressure within the MRS extruder, rather than very low pressure).
In various embodiments of the process, the pressure regulation
system may be configured to maintain a pressure within the MRS
extruder of between about 0 millibars and about 25 millibars. In
particular embodiments, such as embodiments in which the PET flakes
have been run through a crystallizer before being extruded in the
MRS extruder, the pressure regulation system may be configured to
maintain a pressure within the MRS extruder of between about 0 and
about 18 millibars. In other embodiments, the pressure regulation
system may be configured to maintain a pressure within the MRS
extruder between about 0 and about 12 millibars. In still other
embodiments, the pressure regulation system may be configured to
maintain a pressure within the MRS extruder between about 0 and
about 8 millibars. In still other embodiments, the pressure
regulation system may be configured to maintain a pressure within
the MRS extruder between about 5 millibars and about 10 millibars.
In particular embodiments, the pressure regulation system may be
configured to maintain a pressure within the MRS extruder at about
5 millibars, about 6 millibars, about 7 millibars, about 8
millibars, about 9 millibars, or about any suitable pressure
between about 0 millibars and about 25 millibars.
[0073] In particular embodiments, the crystallizer causes the
flakes to at least partially reduce in size, which may, for
example, reduce a potential for the flakes to stick together. In
particular embodiments, the crystallizer may particularly reduce
stickiness of larger flakes, which may, for example, include flakes
comprising portions of the ground PET bottles which may be thicker
than other portions of the PET bottles (e.g., flakes ground from a
threaded portion of the PET bottle on which a cap would typically
be screwed).
Use of Curbside Recycling v. Deposit Bottles in Process
[0074] In various embodiments, the system is configured to utilize
recycled PET of varying quality in the process described above. For
example, in various embodiments, the system is configured to
produce bulked continuous carpet filament from PET derived from PET
bottles sourced from curbside recycling sources (e.g., PET bottles
that were collected as part of a general bulk recycling program or
other recycling source) as well as deposit PET bottles (e.g.,
bottles returned as part of a deposit program). In various
embodiments, Curbside recycled bottles may require more thorough
processing in order to produce bulked continuous filament, as
curbside recycled PET bottles may be mixed in with and otherwise
include contaminants such as, for example: other recyclable goods
(e.g., paper, other plastics, etc.), garbage, and other non-PET
bottle items due to imperfect sorting of recycled goods or for any
other reason. Deposit PET bottles may include PET bottles with
fewer unwanted contaminants due in part because deposit PET bottles
may be collected separately from other recyclable or disposable
goods.
[0075] In various embodiments, curbside recycled PET bottles
acquired during particular times of year may include more
impurities and other contaminants than at other times of the year.
For example, curbside recycled PET bottles collected during summer
months may comprise a higher percentage of clear PET bottles (e.g.,
water bottles) at least in part due to additional water consumption
during summer months.
[0076] In various embodiments, the system described above may be
configured to adjust particular components of the process based at
least in part on the source of recycled PET being used to produce
the bulked continuous carpet filament. For example, because deposit
PET bottles include fewer impurities that need to be removed during
the initial cleaning and sorting phases of the process, the
pressure regulation system may be configured to maintain a pressure
within the MRS extruder that is higher than a pressure that it
would be configured to maintain for PET flake derived from curbside
recycled PET bottles. In a particular embodiment, the pressure
regulation system may be configured to maintain a pressure within
the MRS extruder of between about 0 millibars and about 12
millibars when flakes derived from deposit PET bottles are passing
through the MRS extruder. In still other embodiments, the pressure
regulation system may be configured to maintain a pressure within
the MRS extruder of between about 5 millibars and about 10
millibars in such instances.
[0077] In various embodiments, the system is configured to
determine a suitable pressure at which to maintain the pressure
within the MRS extruder based at least in part on the source of the
recycled PET. In other embodiments, the system is configured to
omit one or more of the steps above or include one or more
additional steps to the steps described above based at least in
part on the source of the recycled PET.
The Use of Colored PET and Color Additives
[0078] In various embodiments, systems for manufacturing recycled
bulked continuous filament described above may utilize colored
(non-clear) post-consumer PET bottles (e.g., or other containers)
in addition to the clear PET bottles described elsewhere herein.
For example, in particular embodiments, the system may utilize
blue, green, amber or any other suitable colored bottles in the
production of recycled BCF (e.g., rather than removing
substantially all of the colored PET from the recycled PET in the
initial stages of the process). In certain embodiments, the process
includes one or more additional steps that include, for example,
adding one or more color additives (e.g., one or more solution dye
color concentrates), which may, for example, dilute a discoloration
of the resulting recycled fiber caused by using colored PET in the
recycling process.
[0079] Flake Color Ratios
[0080] In various embodiments, the PET bottles used in the
production of recycled BCF may include particular percentages of
clear and colored bottles (e.g., by volume, by mass, etc.). For
example, in particular embodiments, recycled BCF may be produced
using at least about 80% (e.g., 80%) clear bottles and no more than
about 20% (e.g., 20%) colored bottles. In particular embodiments,
the colored bottles that the system uses along with clear bottles
to produce the recycled BCF may include only recycled bottles of a
particular color (e.g., only green bottles, only blue bottles, only
amber bottles, etc.). In particular embodiments, the system may be
configured to use bottles of a particular shade of a particular
color. For example, in various embodiments, the system may be
configured to utilize lighter blue bottles (e.g., bottles of a
particular light shade of blue) but not to use darker blue bottles.
In still other embodiments, the system may be configured to use any
suitable colored bottles (e.g., or other sources of recycled PET)
in any suitable ratio.
[0081] In various embodiments, the process may utilize between
about 6.5 percent (e.g., 6.5 percent) and about nine percent (e.g.,
nine percent) colored PET with the remainder being clear PET. In
other embodiments, the process may use between about six and about
ten percent colored PET. In still other embodiments, the process
may use up to about ten percent colored PET with balance
substantially clear PET. In still other embodiments, the process
may utilize between about one percent colored PET and about ten
percent colored PET with balance substantially clear PET. In other
embodiments, the process may use any other suitable ratio of
colored recycled PET to clear recycled PET.
Use of Colored Flake Based on Desired Carpet Color
[0082] In various embodiments, an amount of non-clear PET bottles
used in the process may be based at least in part on a color of
carpet into which the recycled BCF produced by the process will
ultimately be made. For example, for darker carpets, the recycled
BCF used in their creation may be produced using a higher
percentage of colored (e.g., non-clear) PET bottles. In various
embodiments, the use of a higher percentage of colored PET bottles
may result in darker recycled BCF filament, which may, for example,
be unsuitable for the production of particular colored carpets
(e.g., lighter carpets). Carpets which will ultimately be dyed in
darker colors (e.g., or solution dyed into a darker color) may be
more suitable for production using recycled BCF produced at least
partially from colored PET bottles. For example, the production of
recycled BCF for use in brown carpets may utilize at least a
particular amount of amber PET bottles in the recycling process
(e.g., 20% amber and 80% clear, or any other suitable ratio).
[0083] In a particular example, the system may use 2% or less of
non-clear PET bottles in the process when producing relatively
light-colored BCF. This may help to reduce or eliminate the need to
use offsetting color concentrate (as discussed in greater detail
below) to achieve the desired light-colored BCF.
[0084] In certain situations, it may be advantageous to use high
percentages of non-clear PET bottles since doing so may reduce the
amount of solution dye needed to achieve the desired color. For
example, it may be advantageous to use over about 80%, over about
90%, over about 95%, or about 100% non-clear PET in using the
process to produce certain dark-colored (or other colored) recycled
BCF. For example, in various embodiments, it may be advantageous to
use over 95% non-clear PET in producing dark-green recycled BCF
since doing so may reduce the amount of solution dye needed to
attain the desired dark-green color.
[0085] In various embodiments, it may be acceptable to use the
percentages of non-clear PET that are commonly available in
purchased lots of curbside recycled bottles. Such percentages
typically range from between about 6.5% to 9.5% non-clear PET. In
particular situations, where such ranges are acceptable, the system
is adapted not to sort non-clear PET from clear PET. Rather,
non-clear and clear PET are processed and used together. However,
non-PET polymers may be separated from the mix and discarded as
described above.
[0086] Use of Offsetting Color Concentrate with Colored PET
[0087] In particular embodiments, the system is configured to use
any suitable solution dyeing technique to at least partially offset
(e.g., substantially offset) any discoloration of the BCF filament
resulting from the above process when utilizing colored recycled
PET. In various embodiments, the system is configured to add a
color concentrate to polymer flakes prior to extrusion (e.g., or to
polymer melt during or after extrusion) in order to at least
partially offset a coloration of the resultant filament due to the
use of colored recycled PET. In particular embodiments, the color
concentrate may include any suitable color concentrate, which may,
for example, result in a particular color of polymer fiber (e.g.,
bulked continuous filament) following extrusion. In various
embodiments, adding color concentrate to the flakes prior to
extrusion may result in polymer filament that is at least partially
impregnated (e.g., impregnated) with a color pigment. In various
embodiments, the impregnated color pigment may offset any
discoloration of the resulting fiber that may have resulted due to
the use of colored recycled PET in the extrusion process. In
particular embodiments, carpet produced from solution dyed filament
may be highly resistant to color loss through fading from sunlight,
ozone, harsh cleaning agents such as bleach, or other factors.
[0088] In various embodiments, the color concentrate includes any
suitable dispersion of color in a compatible carrier. In some
embodiments, color concentrates are designed so that, when added to
a natural resin (e.g., PET) in a set proportion, they color the
resin substantially evenly (e.g., evenly) to match a desired color.
In some embodiments, the color may comprise mixtures of pigments,
which may, for example, include particles of insoluble colored
material, in the resin. In other embodiments, color concentrates
may include one or more polymer-soluble dyes that are suitable
alone or in combination with one or more pigments.
[0089] In particular embodiments, the system is configured to add
between about two percent (e.g., two percent) and about three
percent (e.g., three percent) color concentrate by mass to the
polymer flake. In other embodiments, the system is configured to
add between about zero percent (e.g., zero percent) and about three
percent (e.g., three percent) color concentrate by mass or volume.
In still other embodiments, the system is configured to add up to
about six percent (e.g., six percent) color concentrate by mass to
the polymer flake prior to extrusion. In some embodiments, the
system is configured to add between about one percent (e.g., one
percent) and about three percent (e.g., three percent) color
concentrate by mass to the polymer flake. In still other
embodiments, the system is configured to add any suitable ratio of
color concentrate to polymer flake in order to achieve a particular
color of molten polymer (and ultimately polymer fiber) following
extrusion.
[0090] FIG. 4 depicts an embodiment in which color concentrate is
added to the polymer flake (e.g., mix of colored and clear PET
flake) prior to feeding the flake through the first single-screw
extruder section 410. It should be understood that, in other
embodiments, the color concentrate may be added during any other
suitable phase of the process described in this document. For
example, in various embodiments, such as any of the examples
discussed above, the system may be configured to add the color
concentrate following extrusion of the polymer flake by the first
single-screw extruder section 410 but prior to feeding the
resultant polymer melt through the extruder's MRS section 420
discussed herein. In still other embodiments, the system may add
the color concentrate after the flake has passed through the MRS
extruder's MRS section 420 prior to passing the polymer melt
through the second single screw section 440 discussed herein. In
still other embodiments, the system may add the color concentrate
while the flakes and/or polymer melt are being extruded in the
first single-screw extruder section 410, MRS Section 420, second
single screw section 440, or at any other suitable phase of the
process. In still other embodiments, the system may add the color
concentrate during one or more (e.g., a plurality) of the phases of
the process described herein (e.g., the system may add some color
concentrate to the polymer flake prior to passing the flake through
the single-screw extruder section 410 and some additional solution
color concentrate following extrusion through the MRS Section
420).
[0091] In various embodiments, the use of a color concentrate at
least partially masks any coloration of the resulting in a bulked
continuous filament created using the above process using colored
recycled PET. In such embodiments, the resulting bulked continuous
filament may have a color that is substantially similar to a color
of bulked continuous filament produced using substantially only
substantially clear (e.g., clear) recycled PET and a color
concentrate.
[0092] Substantially Automated Solution Dyeing
[0093] In various embodiments, the system is configured to
substantially automatically adjust an amount of color concentrate
added to the polymer flake and/or polymer melt in order to produce
a desired color of BCF filament. In various other embodiments, the
system is configured to substantially automatically determine an
amount of color concentrate to add to the colored PET to
sufficiently offset the color of the colored PET. In such
embodiments, the system may, for example, use a suitable feedback
loop that includes: (1) determining a color of bulked continuous
filament produced by the process; (2) determining whether the color
is acceptable (e.g., the color is determined to be a particular
target color and/or the color is determined to meet one or more
pre-determined color guidelines); and (3) substantially
automatically adjusting an amount of color concentrate being added
to the colored PET upstream based at least in part on the
determined color (whether the determined color is acceptable
according to one or more pre-determined color guidelines). In
particular embodiments, the system is adapted to automatically
adjust an amount of color concentrate being added to the colored
(non-clear) PET to assure that it is sufficient for the resulting
colored PET to satisfy the one or more pre-determined color
guidelines.
[0094] Non-Solution Dyeing to Mask Colored PET in Resultant
Filament
[0095] In various embodiments, the process may utilize any suitable
dyeing technique other than the solution dyeing technique described
above to at least partially mask a coloration of the filament
produced using the recycled BCF process described herein with
colored recycled PET. For example, in various embodiments, the
process may utilize any suitable skein dyeing technique, any
suitable continuous dyeing technique, any suitable space dyeing
technique, any suitable beck dyeing technique, or any other
suitable dyeing technique or suitable combination of dyeing
techniques.
[0096] Mixing of PTT with PET to Increase Dyeability
[0097] In various embodiments, such as embodiments in which the
process includes adding one or more solution dyes to recycled PET
that includes colored PET, the process may include adding
polytrimethylene terephthalate (PTT) (or any other suitable
additive) to the PET prior to extrusion, during extrusion, along
with the color concentrate, separately from the color concentrate,
or at any other suitable time. In various embodiments, the mixture
of PTT (or other additive) and PET may have an enhanced dyeability
compared to PET that has not been mixed with PTT. In particular
embodiments, the process includes using a mixture of between about
five percent (e.g., five percent) and about fourteen percent (e.g.,
fourteen percent) PTT (or other additive) in the mixture by mass or
volume. In other embodiments, the process includes using a mixture
of between about six percent (e.g., six percent) and about ten
percent (e.g., ten percent) PTT (or other additive) in the mixture
by mass or volume. In still other embodiments, the process includes
adding up to about fourteen percent (e.g., fourteen percent) PTT
(or other additive) by volume or mass (e.g., between about zero
percent and about fourteen percent PTT). In various embodiments,
the addition of PTT (or other additive) to the PET may reduce a
cost of dyeing the resulting fiber.
[0098] In various embodiments, the process may utilize virgin PTT.
In still other embodiments, the process may utilize recycled PTT.
In some embodiments, PTT may be recycled from any suitable source
such as, for example, recycled PTT carpet, recycled food
containers, and/or other suitable PTT products. In various
embodiments, the PTT may include recycled PTT recovered (e.g.,
recycled) using the process described herein.
[0099] In various embodiments, the above process may be suitable
for recycling PTT for use in mixing the recycled PTT (or other
suitable additive) with PET to improve dyeability of the PET due to
the similar chemical composition of PTT and PET. The resulting
combination may have a higher durability and resilience than
conventional polyesters (e.g., PET). In particular embodiments, PTT
is particularly useful in the production of carpet due to PTT's
stain-resistant qualities. PTT carpets may, for example, at least
generally maintain their original appearance through simple
vacuuming and hot water extraction. This may, for example, result
in a longer lifespan of carpet produced with PTT. In particular
embodiments, PTT is substantially hydrophobic, which may contribute
to PTT carpet's stain resistance. In various embodiments, PTT
carpeting is also substantially soft (e.g., to the touch). PTT
carpet's softness may result from, for example, a lack of
topically-applied chemicals for stain protection due to PTT's
inherent hydrophobic tendencies. It should be understood, based on
the above discussion, that any suitable additive may be used in
place of, or in addition to, PTT in the examples discussed
above.
[0100] Addition of Dye Enhancers
[0101] In various embodiments, such as embodiments in which the
process includes adding one or more dye enhancers to recycled PET
that includes non-clear PET, the process may include adding DEG (or
any other suitable dye enhancer) to the PET prior to extrusion,
during extrusion, along with color concentrate, separately from
color concentrate, or at any other suitable time. In various
embodiments, the mixture of the dye enhancer and PET may have an
enhanced dyeability compared to PET that has not been mixed with
the dye enhancer. In particular embodiments, the process includes
using a mixture of between about zero percent (e.g., zero percent)
and about five percent (e.g., five percent) dye enhancer (e.g.,
DEG) in the mixture by mass or volume. In certain embodiments, the
process includes using a mixture of between about one percent
(e.g., one percent) and about two percent (e.g., two percent) dye
enhancer (e.g., DEG) in the mixture by mass or volume.
CONCLUSION
[0102] Many modifications and other embodiments of the invention
will come to mind to one skilled in the art to which this invention
pertains having the benefit of the teachings presented in the
foregoing descriptions and the associated drawings. For example,
although the vacuum system discussed above is described as being
configured to maintain the pressure in the open chambers of the MRS
extruder to about 1 mbar, in other embodiments, the vacuum system
may be adapted to maintain the pressure in the open chambers of the
MRS extruder at pressures greater than, or less than, 1 mbar. For
example, the vacuum system may be adapted to maintain this pressure
at between about 0.5 mbar and about 12 mbar.
[0103] Similarly, although various embodiments of the systems
described above may be adapted to produce carpet filament from
substantially only recycled PET (so the resulting carpet filament
would comprise, consist of, and/or consist essentially of recycled
PET), in other embodiments, the system may be adapted to produce
carpet filament from a combination of recycled PET and virgin PET.
The resulting carpet filament may, for example, comprise, consist
of, and/or consist essentially of between about 80% and about 100%
recycled PET, and between about 0% and about 20% virgin PET.
[0104] Furthermore, it should be understood that when ratios of
polymers are discussed herein (e.g., as a percentage) such as a
ratio of colored recycled PET to clear recycled PET, color
concentrate to polymer flake, etc., the percentages may include a
percentage by volume, a percentage by mass, a percentage by weight,
or any other suitable relative measure.
[0105] Also, while various embodiments are discussed above in
regard to producing carpet filament from PET, similar techniques
may be used to produce carpet filament from other polymers.
Similarly, while various embodiments are discussed above in regard
to producing carpet filament from PET, similar techniques may be
used to produce other products from PET or other polymers.
[0106] In addition, it should be understood that various
embodiments may omit any of the steps described above or add
additional steps.
[0107] In light of the above, it is to be understood that the
invention is not to be limited to the specific embodiments
disclosed and that modifications and other embodiments are intended
to be included within the scope of the appended claims. Although
specific terms are employed herein, they are used in a generic and
descriptive sense only and not for the purposes of limitation.
* * * * *