A method of manufacturing bulked continuous carpet filament which, in various embodiments, comprises: (A) washing a plurality of flakes of recycled PET; (B) providing a PET crystallizer; (C) after the step of washing the plurality of flakes, passing the plurality of flakes of recycled PET through the PET crystallizer; (D) at least partially melting the plurality of flakes into a polymer melt; (E) providing a multi-rotating screw (MRS) extruder having an MRS section; and a vacuum pump in communication with the MRS section; (F) using the vacuum pump to reduce a pressure within the MRS Section; (G) after the step of passing the plurality of flakes through the PET crystallizer, passing the polymer melt through the MRS Section; and (H) after the step of passing the polymer melt through the MRS extruder, forming the polymer melt into bulked continuous carpet filament.

A multi-shaft kneading machine includes a channel and two screws rotatable around first axes of rotation. A pair of gate rods sandwich the two screws and are rotatable around second axes of rotation. Each of the pair of gate rods has two recess parts that form respective spaces through which the two screws penetrate. Each of the pair of gate rods has a first contact surface, which comes into surface contact with a screw when a gate rod is rotated to a minimum degree-of-opening position. Large diameter parts are fitted into the groove of the cylinder, and a small diameter part have a radius of curvature equal to half a distance between two second axes of rotation and smaller than a radius of curvature of the large diameter parts. The small diameter parts of the pair of gate rods are in contact with each other.

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 flakes through a PET crystallizer; (E) passing the group of flakes through an MRS extruder while maintaining the pressure within the MRS portion of the MRS extruder below about 18 millibars; (F) passing the resulting polymer melt through at least one filter having a micron rating of less than about 50 microns; and (G) forming the recycled polymer into bulked continuous carpet filament that consists essentially of recycled PET.

There is provided with a screw that is inserted into a cylinder an inside of which a material is loaded, and is rotatably supported in both end portions on an upstream side and a downstream side, or in an end portion on the upstream side, in the cylinder; a first kneading blade including a plurality of first blades that are helically provided on the screw and send the material toward the downstream side with rotation of the screw; and a second kneading blade including a second blade that is helically provided on the screw and returns the material, which is sent toward the downstream side by the first kneading blade, toward the upstream side, the number of blades in the second blade being smaller than the number of blades in the first blade.

The present disclosure provides an extruder that includes: at least one screw that extends along an axial direction, the screw including a downstream end positioned downstream in a conveying direction of raw material that is conveyed along the axial direction in accordance with rotation of the screw; a housing that houses the screw; and at least one axial support that axially supports the downstream end of the screw, the axial support including at least one rectifier plate.

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 flakes through a PET crystallizer; (E) passing the group of flakes through an MRS extruder while maintaining the pressure within the MRS portion of the MRS extruder below about 18 millibars; (F) passing the resulting polymer melt through at least one filter having a micron rating of less than about 50 microns; and (G) forming the recycled polymer into bulked continuous carpet filament that consists essentially of recycled PET.

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 flakes through a PET crystallizer; (E) passing the group of flakes through an MRS extruder while maintaining the pressure within the MRS portion of the MRS extruder below about 18 millibars; (F) passing the resulting polymer melt through at least one filter having a micron rating of less than about 50 microns; and (G) forming the recycled polymer into bulked continuous carpet filament that consists essentially of recycled PET.

A system for extrusion of material, for example chopped waste plastic, comprises a treatment device (101) for extruding the material and a feeder device (102) comprising a screw conveyor (103) for supplying the material to the treatment device. A screw element (104) of the screw conveyor has: a) a conical profile so that a diameter of the screw element decreases in a moving direction of the material and/or b) a thread-pitch decreasing in the moving direction of the material and/or c) an axial thickness of a screw thread crest increasing in the moving direction. The conical profile of the screw element and/or the thread-pitch decreasing in the moving direction and/or the axial thickness of the screw thread crest increasing in the moving direction improve the ability of the screw conveyor to compact the material and thereby to supply a sufficiently uniform material flow to the treatment device.

A multi-shaft kneading machine includes a channel and two screws rotatable around first axes of rotation. A pair of gate rods sandwich the two screws and are rotatable around second axes of rotation. Each of the pair of gate rods has two recess parts that form respective spaces through which the two screws penetrate. Each of the pair of gate rods has a first contact surface, which comes into surface contact with a screw when a gate rod is rotated to a minimum degree-of-opening position. Large diameter parts are fitted into the groove of the cylinder, and a small diameter part have a radius of curvature equal to half a distance between two second axes of rotation and smaller than a radius of curvature of the large diameter parts. The small diameter parts of the pair of gate rods are in contact with each other.

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.