Systems and methods for manufacturing bulked continuous filament

• US 8,597,553 B1
• Filed: 12/20/2012
• Issued: 12/03/2013
• Est. Priority Date: 05/31/2012
• Status: Active Grant

• Current Assignee: Aladdin Manufacturing Corporation (Mohawk Industries Incorporated)
• Original Assignee: Mohawk Industries Incorporated
• Inventors: Clark, Thomas
• Primary Examiner(s): Tentoni, Leo B
• Application Number:
  US13/721,955
• Publication Number:
  US 20130324692A1
• Time in Patent Office: 348 Days
• Field of Search: 264/40.1, 264/101, 264/102, 264/169, 264/211.22, 264/211.23
• US Class Current: 264/40.1
• CPC Class Codes: B01D 29/0095 Flat filtering elements B01D25/12, B01D25/26 take precedence
• CPC Class Codes: B07C 2501/0036 Sorting out metallic particles
• CPC Class Codes: B29B 17/00 Recovery of plastics or other constituents of waste material containing plastics; volume reduction of waste plastics, e.g. by mechanical compacting or melting disposal of solid waste B09B; chemical recovery C08J11/00
• CPC Class Codes: B29B 17/02 Separating plastics from other materials
• CPC Class Codes: B29B 2013/002 Extracting undesirable residual components, e.g. solvents, unreacted monomers, from material to be moulded
• CPC Class Codes: B29B 2013/005 Degassing undesirable residual components, e.g. gases, unreacted monomers, from material to be moulded
• CPC Class Codes: B29B 2017/0015 Washing, rinsing
• CPC Class Codes: B29B 2017/0203 Separating plastics from plastics
• CPC Class Codes: B29B 2017/0224 Screens, sieves
• CPC Class Codes: B29B 7/427 with independently driven screws rotating about the same axis, e.g. oscillating axially; with axially oscillating screws B29B7/423 takes precedence
• CPC Class Codes: B29B 7/485 with three or more shafts provided with screws
• CPC Class Codes: B29B 7/486 with screws surrounded by a casing provided with grooves or cavities
• CPC Class Codes: B29B 7/726 Measuring properties of mixture, e.g. temperature or density B29B7/724 takes precedence
• CPC Class Codes: B29B 7/7466 Combinations of similar mixers
• CPC Class Codes: B29C 2791/003 Making articles of indefinite length B29C53/48 takes precedence
• CPC Class Codes: B29C 2791/006 Using vacuum
• CPC Class Codes: B29C 2948/922 Viscosity; Melt flow index [MFI]; Molecular weight
• CPC Class Codes: B29C 2948/9238 Feeding, melting, plasticising or pumping zones, e.g. the melt itself
• CPC Class Codes: B29C 2948/9239 Screw or gear
• CPC Class Codes: B29C 2948/92514 Pressure
• CPC Class Codes: B29C 2948/92876 : Feeding, melting, plasticising or pumping zones, e.g. the melt itself
• CPC Class Codes: B29C 37/006 : Degassing moulding material or draining off gas during moulding venting means in moulds B29C33/10
• CPC Class Codes: B29C 48/05 : Filamentary, e.g. strands
• CPC Class Codes: B29C 48/144 : at the plasticising zone
• CPC Class Codes: B29C 48/145 : at a venting zone
• CPC Class Codes: B29C 48/255 : Flow control means, e.g. valves flow dividers B29C48/695
• CPC Class Codes: B29C 48/2552 : provided in the feeding, melting, plasticising or pumping zone, e.g. screw, barrel, gear-pump or ram
• CPC Class Codes: B29C 48/38 : using two or more serially arranged screws in the same barrel
• CPC Class Codes: B29C 48/385 : using two or more serially arranged screws in separate barrels
• CPC Class Codes: B29C 48/40 : using two or more parallel screws or at least two parallel non-intermeshing screws, e.g. twin screw extruders
• CPC Class Codes: B29C 48/425 : using three or more screws serially arranged screws B29C48/38, B29C48/385
• CPC Class Codes: B29C 48/43 : Ring extruders
• CPC Class Codes: B29C 48/435 : Sub-screws
• CPC Class Codes: B29C 48/44 : Planetary screws
• CPC Class Codes: B29C 48/70 : comprising means for dividing, distributing and recombining melt flows
• CPC Class Codes: B29C 48/765 : in the extruder apparatus
• CPC Class Codes: B29C 48/766 : in screw extruders
• CPC Class Codes: B29C 48/767 : through a degassing opening of a barrel
• CPC Class Codes: B29C 48/92 : Measuring, controlling or regulating
• CPC Class Codes: B29D 99/0078 : Producing filamentary materials
• CPC Class Codes: B29K 2067/003 : PET, i.e. poylethylene terephthalate
• CPC Class Codes: B29K 2105/0067 : Melt
• CPC Class Codes: B29K 2105/26 : Scrap or recycled material
• CPC Class Codes: C08J 11/04 : of polymers
• CPC Class Codes: C08J 11/06 : without chemical reactions
• CPC Class Codes: C08J 2367/02 : Polyesters derived from dicarboxylic acids and dihydroxy compounds; C08J2367/06 takes precedence
• CPC Class Codes: D01D 1/103 : De-aerating
• CPC Class Codes: D01D 1/106 : Filtering
• CPC Class Codes: D01D 5/00 : Formation of filaments, threads, or the like
• CPC Class Codes: D01D 5/08 : Melt spinning methods D01D5/0023 takes precedence
• CPC Class Codes: D01F 6/62 : from polyesters
• CPC Class Codes: D10B 2503/04 : Floor or wall coverings; Carpets
• CPC Class Codes: Y02P 20/143 : the feedstock being recycled material, e.g. plastics
• CPC Class Codes: Y02W 30/62 : Plastics recycling; Rubber recycling
• CPC Class Codes: Y02W 30/64 : Paper recycling

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 group of flakes through an MRS extruder while maintaining the pressure within the MRS portion of the MRS extruder below about 1.5 millibars; (E) passing the resulting polymer melt through at least one filter having a micron rating of less than about 50 microns; and (F) forming the recycled polymer into bulked continuous carpet filament that consists essentially of recycled PET.

Claims

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

(A) providing a multi-screw extruder that comprises;

(i) a first satellite screw extruder, said first satellite screw extruder comprising a first satellite screw that is mounted to rotate about a central axis of said first satellite screw;

(ii) a second satellite screw extruder, said second satellite screw extruder comprising a second satellite screw that is mounted to rotate about a central axis of said second satellite screw; and

(iii) a pressure regulation system that is adapted to maintain a pressure within said first and second satellite screw extruders between about 0 millibars and about 1.8 millibars;

(B) using said pressure regulation system to reduce a pressure within said first and second satellite screw extruders to between about 0 millibars and about 1.8 millibars;

(C) while maintaining said pressure within said first and second satellite screw extruders between about 0 millibars and about 1.8 millibars, passing a melt comprising recycled polymer through said multi-screw extruder so that;

(1) a first portion of said melt passes through said first satellite screw extruder, and (2) a second portion of said melt passes through said second satellite screw extruder; and

(D) after said step of passing said melt of recycled polymer through said multi-screw extruder, forming said recycled polymer into bulked continuous carpet filament.

2. The method of claim 1, wherein said multi-screw extruder comprises a satellite screw extruder support system that is adapted to rotate said first and second satellite screws about a main axis, said main axis being substantially parallel to both:

(a) said central axis of said first satellite screw; and

(b) said central axis of said second satellite screw.

3. The method of claim 2, wherein said step of passing said melt of recycled polymer through said multi-screw extruder occurs while said first and second satellite screw extruders are orbitally rotating about said main axis.

4. The method of claim 1, wherein said step of using said pressure regulation system to reduce a pressure within said first and second satellite screw extruders to between about 0 millibars and about 1.8 millibars comprises using said pressure regulation system to reduce a pressure of said first and second satellite screw extruders to between about 0 millibars and about 1.0 millibar.

5. The method of claim 4, wherein said pressure regulation system comprises a jet vacuum pump.

6. The method of claim 2, wherein:

said satellite screw extruder support system comprises a drum that is adapted to rotate about said main axis;

said drum defines a first screw barrel having a central axis that is substantially parallel to said main axis;

said drum defines a second screw barrel having a central axis that is substantially parallel to said main axis;

said first satellite screw is rotatably mounted within said first screw barrel; and

said second satellite screw is rotatably mounted within said second screw barrel.

7. The method of claim 2, wherein

said extruder comprises a third satellite screw extruder, said third satellite screw extruder comprising a third satellite screw that is mounted to rotate about a central axis of said third satellite screw;

said pressure regulation system is adapted to maintain a pressure within said third satellite screw extruder between a pressure of about 0 millibars and about 2 millibars;

said satellite screw extruder support system is adapted to rotate said third satellite screw about said main axis;

said main axis is substantially parallel to said central axis of said third satellite screw; and

said step of passing said melt of recycled polymer through said multi-screw extruder comprises passing a third portion of said melt through said third satellite screw extruder.

8. The method of claim 1, wherein:

said extruder is a first extruder; and

said method further comprises;

passing a plurality of flakes of recycled PET through a second extruder; and

while passing said plurality of flakes through said second extruder, using said second extruder to heat said plurality of flakes to a temperature that is sufficient to at least substantially melt said plurality of flakes to form said polymer melt.

9. The method of claim 8, wherein said method further comprises:

before said step of passing said plurality of flakes through said second extruder;

washing said plurality of flakes;

scanning said washed plurality of flakes to identify any of said plurality of flakes that comprise material other than PET; and

removing at least one of said identified flakes that comprise material other than PET.

10. The method of claim 1, wherein, after said step of passing said melt of recycled polymer through said multi-screw extruder, said polymer melt has an intrinsic viscosity of between about 0.79 dL/g and about 1.00 dL/g.

11. The method of claim 1, further comprising, after said step of passing said melt of recycled polymer through said multi-screw extruder, passing said polymer melt though at least one filter having a micron rating of less than about 25 microns.

12. The method of claim 1, wherein said step of forming said recycled polymer into bulked continuous carpet filament comprises spinning said polymer melt to form said bulked continuous carpet filament.

13. The method of claim 1, further comprising, before said step of forming said recycled polymer into bulked continuous carpet filament:

using a viscosity sensor to determine whether an intrinsic viscosity of at least a portion of recycled polymer is within a pre-determined range; and

in response to determining said intrinsic viscosity is not within a predetermined range, adjusting said pressure regulation system to lower said internal pressure of said extruder.

14. A method of manufacturing carpet filament comprising the steps of:

(A) washing a group of polymer flakes to remove at least a portion of one or more contaminants from a surface of said flakes, said 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) after said step of washing said first plurality of flakes;

(i) scanning said washed group of flakes to identify said second plurality of flakes,

(ii) separating said second plurality of flakes from said first plurality of flakes;

(C) melting said second plurality of flakes to produce a polymer melt;

(D) providing an extruder that extrudes material in a plurality of different extrusion streams;

(E) reducing a pressure within said extruder to between about 0 millibars and about 1.5 millibars;

(F) while maintaining said pressure within said extruder between about 0 millibars and about 1.5 millibars, passing said polymer melt through said extruder so that said polymer melt is divided into a plurality of extrusion streams, each having a pressure between about 0 millibars and about 1.5 millibars;

(G) after passing said polymer melt through said extruder, filtering said polymer melt through at least one filter; and

(H) after passing said polymer melt through said filter, forming said recycled polymer into bulked continuous carpet filament.

15. The method of claim 14, wherein said extruder comprises:

(A) a first satellite screw extruder, said first satellite screw extruder comprising a first satellite screw that is mounted to rotate about a central axis of said first satellite screw;

(B) a second satellite screw extruder, said second satellite screw extruder comprising a second satellite screw that is mounted to rotate about a central axis of said second satellite screw;

(C) a pressure regulation system that is adapted to maintain a pressure within said first and second satellite screw extruders between a pressure of about 0 millibars and about 1.5 millibars as said polymer melt passes through said first and second screw extruders; and

(D) a satellite screw extruder support system that is adapted to orbitally rotate said first and second satellite screws about a main axis as said polymer melt passes through said first and second screw extruders, said main axis being substantially parallel to both;

(1) said central axis of said first satellite screw; and

(2) said central axis of said second satellite screw.

16. The method of claim 15, wherein said pressure regulation system is configured to lower said pressure within said extruder to between about 0 millibars and about 1.3 millibars.

17. The method of claim 15, wherein said at least one filter comprises:

a first filter having a micron rating of less than about 50 microns; and

a second filter having a micron rating of less than about 30 microns.