A screw includes a screw main body, a conveyance portion conveying a raw material, and a passage provided in the screw main body. The passage includes a first passage element, a second passage element, and a third passage element. The screw main body has a plurality of cylindrical bodies arranged in an axial direction of the rotating shaft. At least a portion of the conveyance portion is formed on outer peripheral surfaces of the cylindrical bodies adjacent to each other, and the passage is formed in the cylindrical body so as to cross over between the adjacent cylindrical bodies.

A compounding extruder includes a melting section having a first cylindrical tube having a first inlet to receive a propylene polymer and a first outlet to discharge a first melt composition and a first screw arranged in the first cylindrical tube and having a first length, a first outer screw diameter Do1 and a first inner screw diameter to convey the propylene polymer and to the first outlet and a mixing section comprising a second cylindrical tube having a second inlet to receive, the first melt composition from the first outlet, an end having a second outlet and a side inlet between the second inlet and the second outlet to receive a further component, and a second screw arranged in the second cylindrical to convey the first melt composition and the further component to the second outlet, wherein Do1 is 0.82 to 1.2×Do2.

A compounding extruder includes a melting section having a first cylindrical tube having a first inlet to receive a propylene polymer and a first outlet to discharge a first melt composition and a first screw arranged in the first cylindrical tube and having a first length, a first outer screw diameter Do1 and a first inner screw diameter to convey the propylene polymer and to the first outlet and a mixing section comprising a second cylindrical tube having a second inlet to receive, the first melt composition from the first outlet, an end having a second outlet and a side inlet between the second inlet and the second outlet to receive a further component, and a second screw arranged in the second cylindrical to convey the first melt composition and the further component to the second outlet, wherein Do1 is 0.82 to 1.2×Do2.

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.

A device for producing a dyed plastic melt and an undyed plastic melt includes a multi-shaft screw extruder, a first metering installation, a second metering installation, and a control installation for selecting between a first operating mode for producing the dyed plastic melt and a second operating mode for producing the undyed plastic melt. The first metering installation serves for feeding an undyed plastic material through a first infeed opening into a housing of the multi-shaft screw extruder, and the second metering installation serves for feeding at least one color granulate through a second infeed opening into the housing. The plastic material is fed exclusively by way of the first infeed opening such that residual color granulate or dyeing agent contained therein, respectively, which is still located in the second metering installation or in the region of the second infeed opening does not contaminate the undyed plastic melt.

A device for producing a dyed plastic melt and an undyed plastic melt includes a multi-shaft screw extruder, a first metering installation, a second metering installation, and a control installation for selecting between a first operating mode for producing the dyed plastic melt and a second operating mode for producing the undyed plastic melt. The first metering installation serves for feeding an undyed plastic material through a first infeed opening into a housing of the multi-shaft screw extruder, and the second metering installation serves for feeding at least one color granulate through a second infeed opening into the housing. The plastic material is fed exclusively by way of the first infeed opening such that residual color granulate or dyeing agent contained therein, respectively, which is still located in the second metering installation or in the region of the second infeed opening does not contaminate the undyed plastic melt.

An extruder screw includes a screw body. The screw body is rotated about an axis parallel to a direction of conveyance of a raw material. A conveyance portion having a flight is provided on the outer peripheral surface of the screw body. The flight is configured to convey the raw material along the axis of the screw body when the screw body is rotated. A passage for permitting the raw material fed by the flight to pass therethrough to the outer peripheral surface of the screw body is provided in the screw body in a position deviated from the axis of the screw body.

An extruder screw includes a screw body. The screw body is rotated about an axis parallel to a direction of conveyance of a raw material. A conveyance portion having a flight is provided on the outer peripheral surface of the screw body. The flight is configured to convey the raw material along the axis of the screw body when the screw body is rotated. A passage for permitting the raw material fed by the flight to pass therethrough to the outer peripheral surface of the screw body is provided in the screw body in a position deviated from the axis of the screw body.

An extruder includes a screw for extruder provided with a screw element for kneading a raw material, and a barrel including a cylinder portion in which the screw is inserted so as to be rotatable. A plurality of screw elements identical with the screw element are provided in a longitudinal direction of the screw under a certain rule. The barrel is integrated by combining a plurality of barrel blocks blocked. Each of the plurality of barrel blocks is configured in accordance with a length of the screw element provided in the longitudinal direction of the screw.

An extruder includes a screw for extruder provided with a screw element for kneading a raw material, and a barrel including a cylinder portion in which the screw is inserted so as to be rotatable. A plurality of screw elements identical with the screw element are provided in a longitudinal direction of the screw under a certain rule. The barrel is integrated by combining a plurality of barrel blocks blocked. Each of the plurality of barrel blocks is configured in accordance with a length of the screw element provided in the longitudinal direction of the screw.