Methods for manufacturing bulked continuous filament

Patent metadata

Field	Value
Publication number	US-10647046-B2
Application number	US-201816213694-A
Country	US
Kind code	B2
Filing date	Dec 7, 2018
Priority date	May 31, 2012
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

A method of manufacturing bulked continuous carpet filament which, in various embodiments, comprises: (A) grinding recycled PET bottles into a group of flakes; (B) washing the flakes; (C) identifying and removing impurities, including impure flakes, from the group of flakes; (D) passing the flakes through a PET crystallizer; (E) passing the group of flakes through an MRS extruder while maintaining the pressure within the MRS portion of the MRS extruder below about 18 millibars; (F) passing the resulting polymer melt through at least one filter having a micron rating of less than about 50 microns; and (G) forming the recycled polymer into bulked continuous carpet filament that consists essentially of recycled PET.

First claim

What is claimed is:

1. A method of manufacturing bulked continuous carpet filament, the method comprising:
(A) washing a plurality of flakes of recycled PET;
(B) providing a PET crystallizer;
(C) after the step of washing the first plurality of flakes, passing the plurality of flakes of recycled PET through the PET crystallizer to at least partially dry the plurality of flakes of recycled PET;
(D) at least partially melting the plurality of flakes into a polymer melt;
(E) providing a multi-rotating screw (MRS) extruder comprising:
an MRS Section comprising:
a plurality of satellite screws, each of the plurality of satellite screws being at least partially housed within a respective extruder barrel and mounted to rotate about its respective central axis; and a satellite screw extruder support system that is adapted to orbitally rotate each of the plurality of satellite screws about a main axis as each of the plurality of satellite screws rotate about its respective central axis, the main axis being substantially parallel to each respective central axis;
a first single-screw extruder section comprising a first single extruder screw for melting the plurality of flakes of recycled PET to form a polymer melt and feeding the polymer melt into the MRS section;
a second single-screw extruder section comprising a second single extruder screw for transporting the polymer melt away from the MRS section; and
a vacuum pump in communication with the MRS section that is adapted to maintain a pressure within the MRS Section below a pressure of about 25 millibars as the polymer melt passes through the MRS Section;

(F) using the vacuum to reduce a pressure within the MRS Section to below about 25 millibars;
(G) after the step of passing the plurality of flakes through the PET crystallizer and while maintaining the pressure within the MRS Section below about 25 millibars, passing the polymer melt through the MRS Section so that at least a portion of the polymer melt passes through each respective extruder barrel; and
(H) after the step of passing the polymer melt through the MRS extruder, forming the polymer melt into bulked continuous carpet filament.

2. The method of claim 1 , wherein washing the plurality of flakes of recycled PET comprises mixing the plurality of flakes of recycled PET in a series of wash tanks.

3. The method of claim 1 , wherein washing the plurality of flakes of recycled PET comprises washing the plurality of flakes in a heated caustic bath.

4. The method of claim 3 , wherein washing the plurality of flakes of recycled PET in the heated caustic bath comprises washing the plurality of flakes of recycled PET in the heated caustic bath to about 190 degrees Fahrenheit.

5. The method of claim 1 , wherein washing the plurality of flakes of recycled PET comprises washing the plurality of flakes of recycled PET to remove at least a portion of one or more contaminants from a surface of the plurality of flakes.

6. The method of claim 1 , further comprising, before the step of washing the plurality of flakes, grinding a plurality of recycled PET bottles into the plurality of flakes of recycled PET.

7. The method of claim 6 , wherein washing the plurality of flakes of recycled PET comprises using aqueous density separation to separate remnants of bottle caps from the plurality of recycled PET bottles from the plurality of flakes of recycled PET.

8. A method of manufacturing bulked continuous carpet filament from 100% recycled PET, the method comprising:
(A) providing a PET crystallizer;
(B) passing the plurality of flakes of recycled PET through the PET crystallizer to at least partially dry the plurality of flakes of recycled PET;
(C) at least partially melting the plurality of flakes into a polymer melt;
(D) providing a multi-rotating screw (MRS) extruder comprising:
an MRS Section comprising:
a plurality of satellite screws, each of the plurality of satellite screws being at least partially housed within a respective extruder barrel and mounted to rotate about its respective central axis; and a satellite screw extruder support system that is adapted to orbitally rotate each of the plurality of satellite screws about a main axis as each of the plurality of satellite screws rotate about its respective central axis, the main axis being substantially parallel to each respective central axis;
a first single-screw extruder section comprising a first single extruder screw for melting the plurality of flakes of recycled PET to form a polymer melt and feeding the polymer melt into the MRS section;
a second single-screw extruder section comprising a second single extruder screw for transporting the polymer melt away from the MRS section; and
a vacuum pump in communication with the MRS section that is adapted to maintain a pressure within the MRS Section below a pressure of about 25 millibars as the polymer melt passes through the MRS Section;

(E) using the vacuum to reduce a pressure within the MRS Section to below about 25 millibars;
(F) after the step of passing the plurality of flakes through the PET crystallizer and while maintaining the pressure within the MRS Section below about 25 millibars, passing the polymer melt through the MRS Section so that at least a portion of the polymer melt passes through each respective extruder barrel; and
(G) after the step of passing the polymer melt through the MRS extruder, forming the polymer melt into bulked continuous carpet filament from 100% recycled PET and 0% virgin PET.

9. The method of claim 8 , further comprising, before the step of passing the plurality of flakes of recycled PET through the PET crystallizer, washing the plurality of flakes of recycled PET.

10. The method of claim 9 , further comprising, before the step of washing the plurality of flakes, grinding a plurality of recycled PET bottles into the plurality of flakes of recycled PET.

11. The method of claim 10 , wherein washing the plurality of flakes of recycled PET comprises washing the plurality of flakes of recycled PET to remove at least a portion of one or more contaminants from a surface of the plurality of flakes.

12. The method of claim 8 , wherein the crystallizer comprises:
a hopper screw configured to feed the plurality of flakes of recycled PET into the crystallizer; and
a blower configured to blow hot air over the plurality of flakes of recycled PET as the plurality of flakes of recycled PET pass through the crystallizer.

13. The method of claim 8 , wherein the crystallizer is configured to maintain a temperature of between about 140 degrees Celsius and about 180 degrees Celsius within the crystallizer.

14. A method of manufacturing bulked continuous carpet filament, the method comprising:
(A) providing a PET crystallizer;
(B) passing the plurality of flakes of recycled PET through the PET crystallizer to at least partially dry the plurality of flakes of recycled PET;
(C) at least partially melting the plurality of flakes into a polymer melt;
(D) providing a multi-rotating screw (MRS) extruder comprising:
an MRS Section comprising:
a plurality of satellite screws, each of the plurality of satellite screws being at least partially housed within a respective extruder barrel and mounted to rotate about its respective central axis; and a satellite screw extruder support system that is adapted to orbitally rotate each of the plurality of satellite screws about a main axis as each of the plurality of satellite screws rotate about its respective central axis, the main axis being substantially parallel to each respective central axis;
a first single-screw extruder section comprising a first sing

Assignees

• Aladdin Mfg Corp

Inventors

• Clark Thomas R

Classifications

• B29C48/43

  Ring extruders · CPC title

• B29C48/05 Primary

  Filamentary, e.g. strands · CPC title

• B29C48/385

  using two or more serially arranged screws in separate barrels · CPC title

• B29C48/38

  using two or more serially arranged screws in the same barrel · CPC title

• D01D1/103

  De-aerating · CPC title