Methods for manufacturing bulked continuous filament

  • US 10,647,046 B2
  • Filed: 12/07/2018
  • Issued: 05/12/2020
  • Est. Priority Date: 05/31/2012
  • Status: Active Grant
First Claim
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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.

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