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.

We claim: 
     
         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.