Methods for manufacturing bulked continuous filament
A method of recycling a PET-containing material comprises: (1) providing a polymer crystallizer comprising at least one heating element, and at least one blower; (2) providing an MRS extruder having an MRS section comprising a plurality of satellite screws; (3) providing a vacuum pump in fluid communication with the MRS section; (4) grinding and washing the PET-containing material; (5) heating the PET-containing material in the crystallizer to at least partially dry the PET-containing material; (6) shearing the PET-containing material in the MRS extruder to produce a PET-containing melt; (7) increasing a surface area of the PET-containing melt by distributing the PET-containing melt across a plurality of satellite screws in the MRS extruder; (8) drawing off vapors from the PET-containing melt by reducing the pressure in the MRS section with the vacuum pump; (9) collating the PET-containing melt in the MRS extruder; and (10) extruding a recycled PET-containing material.
1. A method of recycling a PET-containing material, comprising:
providing a polymer crystallizer comprising at least one heating element, and at least one blower;
providing a multi-rotating screw (MRS) extruder having 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;
providing a vacuum pump in fluid communication with the MRS section;
grinding and washing the PET-containing material;
heating the PET-containing material in the crystallizer to at least partially dry the PET-containing material;
shearing the PET-containing material in the MRS extruder to produce a PET-containing melt;
increasing a surface area of the PET-containing melt by distributing the PET-containing melt across the plurality of satellite screws in the MRS extruder;
drawing off vapors from the PET-containing melt by reducing the pressure in the MRS section with the vacuum pump;
collating the PET-containing melt in the MRS extruder; and
extruding a recycled PET-containing material, the PET-containing material is either old carpet or recycled PET bottles.
2. The method of claim 1 , wherein the pressure is reduced to between 0 and 25 millibars.
3. The method of claim 1 , wherein the vapors from the PET-containing melt comprise moisture from interstitial water and volatile organic impurities.
4. The method of claim 3 , wherein the moisture from the interstitial water and volatile organic impurities in the PET-containing melt is reduced to below about 50 ppm.
5. The method of claim 1 , wherein the vacuum pump is a jet vacuum pump.
6. A method of purifying a PET polymer, comprising:
grinding and washing a PET-containing material;
heating the PET-containing material in a crystallizer to at least partially dry the PET-containing material, wherein the crystallizer comprises at least one heating element, and at least one blower;
melting the PET-containing material in an MRS extruder, wherein the MRS extruder 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, a viscosity monitor, and a pressure regulation system;
increasing a surface area of the melted PET-containing material by distributing the PET-containing material across the plurality of satellite screws in the MRS extruder;
monitoring a viscosity of the melted PET-containing material within the MRS extruder;
regulating a pressure within the MRS extruder with the pressure regulation system in response to an intrinsic viscosity of the PET-containing melt;
filtering the melted PET-containing material through a filter; and
extruding a purified PET polymer, wherein the PET-containing material is either old carpet or recycled PET bottles.
7. The method of claim 6 , wherein the pressure is reduced to between 0 and 25 millibars.
8. The method of claim 6 , wherein the pressure regulation system comprises a vacuum pump.
9. The method of claim 8 , wherein the vacuum pump is a jet vacuum pump.
10. The method of claim 6 , wherein the at least one heating element is configured to maintain a temperature within the crystallizer to between about 100 degrees Fahrenheit and about 180 degrees Fahrenheit.
11. The method of claim 6 , wherein the at least one heating element is configured to maintain a temperature within the crystallizer to between about 100 degrees Celsius and 180 degrees Celsius.
12. The method of claim 6 , wherein the filter comprises a 40 micron screen filter followed by a 25 micron screen filter.