One embodiment provides a twin-screw extruder which is used to knead materials and has excellent productivity. The twin-screw extruder includes screws. The screws include double thread screws in which first screw portions engage with each other. Ratio D1/C of external diameter D1 of the first screw portion to a shaft distance C ranges from 1.25 to 1.40. The screws further include triple thread screws in which third screw portions engage with each other. Ratio D3/C of external diameter D3 of the third screw portion to the shaft distance C ranges from 1.05 to 1.10. External diameter D2 of a second screw portion decreases gradually from the first screw portion toward the third screw portion.

A method for manufacturing bulked continuous carpet filament, the method comprising: (1) reducing a chamber pressure within a chamber to below about 5 millibars; (2) after reducing the chamber pressure to below about 5 millibars, providing a polymer melt to the chamber; (3) separating the polymer melt into at least eight streams; (4) while the at least eight streams of the polymer melt are within the chamber, exposing the at least eight streams of the polymer melt to the chamber pressure of below about 5 millibars; (5) after exposing the at least eight streams of the polymer melt to the chamber pressure of below about 5 millibars, recombining the at least eight streams into a single polymer stream; and (6) forming polymer from the single polymer stream into bulked continuous carpet filament.

A method of manufacturing bulked continuous carpet filament that includes providing a polymer melt and separating the polymer melt from the extruder into at least eight streams. The multiple streams are exposed to a chamber pressure within a chamber that is below approximately 5 millibars. The streams are recombined into a single polymer stream and formed into bulked continuous carpet filament.

A planetary extruder for producing and processing polymers includes a degassing section. The extruder includes a housing and a bushing arranged therein. The bushing has an internal toothing with a pitch diameter and a root circle. An externally toothed central spindle is arranged within the housing. Planetary spindles rotate about the central spindle between the central spindle and the bushing. A heat transfer fluid is guided through fluid channels which extend helically along an outer surface of the bushing and guide the heat transfer fluid axially. A degassing opening is provided to which a negative pressure is applied for degassing. A minimum radial thickness (t) of the bushing between the root circle of the internal toothing on an inside of the bushing and a bottom of the fluid channels on an outside of the bushing is selected based on the pitch diameter (d) of the internal toothing.

Pressure-sensitive adhesive (PSA) strips, configured or adapted for the residue-free and non-destructive removal by which by substantially expanding it in the plane of adhesion, are provided. The PSA strips comprise at least one adhesive compound layer consisting of a PSA compound, constituted by vinyl aromatic block copolymers and one or more adhesive resins, at least 75 wt.-% (relative to the total amount of resin) of a resin being selected that has a DACP (diacetone alcohol cloud point) of greater than 20 C., and a softening point (ring & ball) of greater than or equal to 70 C., and the PSA compound has being foamed.

Systems for manufacturing bulked continuous carpet filament from polymer, where the systems are configured for: (1) melting polymer (e.g., derived from post-consumer PET bottles) to create a first single stream of polymer melt; (2) separating the first single stream of polymer melt into multiple streams of polymer melt; (3) exposing the multiple streams of polymer melt to a pressure of between about 0 millibars and about 5 millibars; (4) allowing the multiple streams of polymer melt to fall into a receiving section of a melt processing unit; (5) recombining the multiple streams of polymer melt into a second single stream of polymer melt; and (6) providing the second single stream of polymer melt to one or more spinning machines that are configured to form the second single stream of polymer melt into bulked continuous carpet filament.

A method of manufacturing bulked continuous carpet filament from polytrimethylene terephthalate (PTT) with polyethylene terephthalate (PET) comprises: (1) splitting the PTT stream extruded from the primary extruder into a number of polymer streams, each of the plurality of polymer streams having an associated spinning machine; (2) adding a colorant to each split polymer stream; (3) adding PET to the extruded polymer stream downstream of the primary extruder; (4) using one or more static mixing assemblies for each split polymer stream to substantially uniformly mix each split polymer stream and its respective colorant and PET; and (5) spinning each polymer stream with its substantially uniformly mixed colorant and any additives into BCF using the respective spinning machine.

A method of manufacturing bulked continuous carpet filament from a plurality of polymer flakes comprises: (1) providing an extruder; (2) melting and purifying the plurality of polymer flakes into a polymer stream using the extruder; (3) providing a static mixing assembly downstream of the extruder; (4) adding a first liquid colorant to a center of the polymer stream at a first location before the static mixing assembly or along a length of the static mixing assembly; (5) adding a second liquid colorant to the polymer stream at a second location before the static mixing assembly or along a length of the static mixing assembly; (6) using the static mixing assembly to mix the polymer stream with the first and second liquid colorant to create a colored polymer stream; and (7) forming the colored polymer stream into bulked continuous carpet filament.

A method of manufacturing bulked continuous carpet filament that includes providing a polymer melt and separating the polymer melt from the extruder into at least eight streams. The multiple streams are exposed to a chamber pressure within a chamber that is below approximately 25 millibars, or another predetermined pressure. The streams are recombined into a single polymer stream. Polymer from the polymer stream is then formed into bulked continuous carpet filament.

A system comprising: (1) a grinding unit configured to receive and grind recycled PET bottles into a group of polymer flakes comprising up to about ten percent colored polymer flakes and balance substantially clear polymer flakes; (2) a washing unit configured to wash the group of polymer flakes; and (3) an extruder configured to extrude material in a plurality of different extrusion streams. The extruder may be further configured to: (1) receive a concentrate-polymer mixture comprising a mixture of the polymer flakes and a color concentrate; (2) melt the concentrate-polymer mixture to produce a polymer melt; (3) reduce a pressure within the extruder; and (4) pass the polymer melt through the extruder so that the polymer melt is divided into the plurality of extrusion streams. The system may then filter the polymer melt through at least one filter and form the polymer melt into bulked continuous carpet filament.