Methods for manufacturing bulked continuous filament

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.