Methods for manufacturing bulked continuous filament

1. A method of manufacturing bulked continuous carpet filament, the method comprising:

(A) washing a plurality of flakes comprising recycled PET;

(B) providing a PET crystallizer;

(C) after the step of washing the plurality of flakes comprising recycled PET, passing at least a portion of the plurality of flakes comprising recycled PET through the PET crystallizer to at least partially dry a surface of the plurality of flakes comprising recycled PET;

(D) providing an expanded surface area extruder, wherein the expanded surface area extruder defines an expanded surface area extruder inlet and an expanded surface area extruder outlet and comprises:

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;

(E) providing a pressure regulation system configured to reduce a pressure within at least a portion of the expanded surface area extruder below about 25 mbar;

(F) providing a spinning machine defining a spinning machine inlet, wherein the spinning machine inlet is operatively coupled to the expanded surface area extruder outlet;

(G) using the pressure regulation system to reduce the pressure within the at least a portion of the expanded surface area extruder below about 25 mbar;

(H) after passing the plurality of flakes comprising recycled PET through the PET crystallizer, passing the plurality of flakes comprising PET flakes through the expanded surface area extruder via the expanded surface area extruder inlet to at least partially melt the plurality of flakes to form a polymer melt such that at least a portion of the polymer melt passes through each the respective satellite screw; and

(I) substantially immediately after passing the plurality of flakes through the expanded surface area extruder, using the spinning machine to form the polymer melt into bulked continuous carpet filament.

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

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

4. The method of claim 3 , wherein the heated caustic bath is maintained at a concentration of between about 0.6% sodium hydroxide and about 1.2% sodium hydroxide.

5. The method of claim 1 , wherein washing the plurality of flakes comprising recycled PET comprises washing the plurality of flakes comprising 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 5 , wherein:

the plurality of flakes comprise:

a first plurality of flakes that consist essentially of PET; and

a second plurality of flakes that do not consist essentially of PET;

the method further comprises, after the step of washing the plurality of flakes:

(i) scanning the washed group of flakes to identify the second plurality of flakes; and

(ii) separating the second plurality of flakes from the first plurality of flakes; and

passing at least a portion of the plurality of flakes comprising recycled PET through the PET crystallizer comprises passing the first plurality of flakes through the PET crystallizer.

7. The method of claim 1 , further comprising grinding a plurality of recycled PET bottles into the plurality of flakes comprising recycled PET.

8. A method of manufacturing bulked continuous carpet filament, the method comprising:

(A) providing a PET crystallizer;

(B) passing a plurality of flakes comprising recycled PET through the PET crystallizer to at least partially dry a surface of the plurality of flakes comprising recycled PET;

(C) providing an expanded surface area extruder, wherein the expanded surface area extruder defines an expanded surface area extruder inlet and an expanded surface area extruder outlet and comprises:

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;

(D) providing a pressure regulation system configured to reduce a pressure within at least a portion of the expanded surface area extruder below about 25 mbar;

(E) providing a spinning machine defining a spinning machine inlet, wherein the spinning machine inlet is operatively coupled to the expanded surface area extruder outlet;

(F) using the pressure regulation system to reduce the pressure within the at least a portion of the expanded surface area extruder below about 25 mbar;

(G) after passing the plurality of flakes comprising recycled PET through the PET crystallizer, passing the plurality of flakes comprising PET flakes through the expanded surface area extruder via the expanded surface area extruder inlet to at least partially melt the plurality of flakes to form a polymer melt such that at least a portion of the polymer melt passes through each the respective satellite screw; and

(H) substantially immediately after passing the plurality of flakes through the expanded surface area extruder, using the spinning machine to form the polymer melt into bulked continuous carpet filament.

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

10. The method of claim 9 , wherein washing the plurality of flakes comprising recycled PET comprises washing the plurality of flakes comprising recycled PET to remove at least a portion of one or more contaminants from a surface of the plurality of flakes.

11. 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 comprising recycled PET.

12. The method of claim 11 , wherein washing the plurality of flakes comprises using aqueous density separation to separate remnants of bottle caps from the plurality of recycled PET bottles from the plurality of flakes comprising recycled PET.

13. The method of claim 8 , wherein the method comprises manufacturing bulked continuous carpet filament from 100% recycled PET.

14. A method of manufacturing bulked continuous carpet filament, the method comprising:

(A) providing a PET crystallizer;

(B) passing a plurality of flakes comprising recycled PET through the PET crystallizer to at least partially dry a surface of the plurality of flakes comprising recycled PET;

(C) providing an expanded surface area extruder, wherein the expanded surface area extruder defines an expanded surface area extruder inlet and an expanded surface area extruder outlet and comprises:

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;

(D) providing a pressure regulation system configured to reduce a pressure within at least a portion of the expanded surface area extruder below about 25 mbar;

(E) providing a spinning machine defining a spinning machine inlet, wherein the spinning machine inlet is operatively coupled to the expanded surface area extruder outlet;

(F) using the pressure regulation system to reduce the pressure within the at least a portion of the expanded surface area extruder below about 25 mbar;

(G) after passing the plurality of flakes comprising recycled PET through the PET crystallizer, passing the plurality of flakes comprising PET flakes through the expanded surface area extruder via the expanded surface area extruder inlet to at least partially melt the plurality of flakes to form a polymer melt such that at least a portion of the polymer melt passes through each the respective satellite screw;

(H) after passing the plurality of flakes through the expanded surface area extruder, filtering the polymer melt through at least one filter; and

(I) substantially immediately after passing the plurality of flakes through the expanded surface area extruder and filtering the polymer melt through the at least one filter, using the spinning machine to form the polymer melt into bulked continuous carpet filament.

15. The method of claim 14 , wherein the at least one filter has a micron rating of less than about 50 microns.

16. The method of claim 14 , further comprising, before the step of passing the plurality of flakes comprising recycled PET through the PET crystallizer, washing the plurality of flakes.

17. The method of claim 16 , further comprising, before the step of washing the plurality of flakes, grinding a plurality of recycled PET bottles into the plurality of flakes comprising recycled PET.

18. The method of claim 14 , wherein the method comprises manufacturing bulked continuous carpet filament from 100% recycled PET.

19. The method of claim 18 , wherein manufacturing bulked continuous carpet filament from 100% recycled PET substantially immediately after extruding the recycled PET comprises spinning the polymer melt into bulked continuous carpet filament without substantially cooling the polymer melt.

20. The method of claim 14 , wherein the at least one filter comprises a 40 micron screen filter followed by a 25 micron screen filter.