An extruder screw for plasticizing at least one plastic or plastic mixture, including a melting zone, a shaft zone and a mixing zone arranged between the melting zone and the shaft zone, wherein a conveying flight is formed in the melting zone and in the shaft zone, which extends helically along a longitudinal axis of the screw, wherein a conveying flight of the melting zone ends at an end of the melting zone towards the mixing zone and a conveying flight of the shaft zone begins at an end towards the mixing zone. A flight depth of the melting zone continuously decreases along the longitudinal axis of the screw to the mixing zone. Further, an extrusion device having the extruder screw and to a method for plasticizing at least one plastic or plastic mixture.

A producing method for producing a foam-molded product by using a plasticizing cylinder having, from an upstream side in the following order: a plasticization zone, a flow rate adjusting zone and a starvation zone, the producing method includes: plasticizing and melting a thermoplastic resin into a molten resin in the plasticization zone; adjusting a flow rate of the molten resin in the flow rate adjusting zone; allowing the molten resin to be in a starved state in the starvation zone; introducing a pressurized fluid containing the physical foaming agent having a fixed pressure into the starvation zone so as to retain the starvation zone at the fixed pressure; bringing the molten resin in the starved state in contact with the pressurized fluid in the starvation zone in a state in which the starvation zone is retained at the fixed pressure; and molding the molten resin into the foam-molded product.

A producing method for producing a foam-molded product by using a plasticizing cylinder having, from an upstream side in the following order: a plasticization zone, a flow rate adjusting zone and a starvation zone, the producing method includes: plasticizing and melting a thermoplastic resin into a molten resin in the plasticization zone; adjusting a flow rate of the molten resin in the flow rate adjusting zone; allowing the molten resin to be in a starved state in the starvation zone; introducing a pressurized fluid containing the physical foaming agent having a fixed pressure into the starvation zone so as to retain the starvation zone at the fixed pressure; bringing the molten resin in the starved state in contact with the pressurized fluid in the starvation zone in a state in which the starvation zone is retained at the fixed pressure; and molding the molten resin into the foam-molded product.

The method for manufacturing a foamed product uses a manufacturing apparatus having a plasticizing cylinder in which an introduction port for introducing a physical blowing agent into a starvation zone is formed, and an introduction speed adjustment container connected to the introduction port, wherein the manufacturing method comprises: turning a thermoplastic resin into a molten resin; introducing the physical blowing agent at a predetermined pressure into the starvation zone through the introduction speed adjustment container and maintaining the starvation zone at a predetermined pressure; setting the molten resin to a starved state; bringing the molten resin in the starved state and the pressurized fluid into contact with each other; and molding the molten resin into a foamed product. The maximum value of the inner diameter of the introduction speed adjustment container is larger than the inner diameter of the introduction port.

An extruder screw for the plasticizing of at least one plastic material or a plastic material mixture, with a melting zone, a wave zone and a mixing zone arranged between the melting zone and the wave zone, wherein a conveying web extending in a helix-like manner along a screw longitudinal axis is formed in the melting zone and in the wave zone, wherein a conveying web of the melting zone terminates at an end of the melting zone facing the mixing zone, and a conveying web of the wave zone begins at an end facing the mixing zone. The application also relates to an extrusion device with this extruder screw, and a method for plasticizing at least one plastic material or a plastic material mixture.

A method for directly preparing a foamed polylactic acid (PLA) product from a PLA melt includes PLA melt preparation, feeding, and two-stage extrusion. In the two-stage extrusion, a pressure at an outlet of a first-stage twin-screw extruder is 15 MPa to 17 MPa, a PLA melt is fed at a rate of 250 kg/h, a foaming additive is fed at a rate of 7.5 kg/h to 10 kg/h, and a foaming gas is fed at a rate of 2.8 L/h to 7.5 L/h. The method can ensure both foamability and quality of a material and reduce more than ⅓ of energy consumption; and an obtained product has an adjustable foaming rate of 3 to 25, a crystallinity of 40.3% to 48.5%, a tensile strength of 8.7 MPa to 19.6 MPa, and an apparent density of 0.05 g/cm.sup.3 to 0.4 g/cm.sup.3.

An extruder screw for plasticizing at least one plastic or plastic mixture, including a melting zone, a shaft zone and a mixing zone arranged between the melting zone and the shaft zone, wherein a conveying flight is formed in the melting zone and in the shaft zone, which extends helically along a longitudinal axis of the screw, wherein a conveying flight of the melting zone ends at an end of the melting zone towards the mixing zone and a conveying flight of the shaft zone begins at an end towards the mixing zone. A flight depth of the melting zone continuously decreases along the longitudinal axis of the screw to the mixing zone. Further, an extrusion device having the extruder screw and to a method for plasticizing at least one plastic or plastic mixture.

A method for producing a rubber member according to the present invention includes the steps of: supplying a rubber composition to a cylinder provided in an extruder; extruding the rubber composition to a downstream side of the cylinder while kneading the rubber composition in an internal space of the cylinder that includes a plurality of protruding members protruding from an inner wall surface of the cylinder; compressing the rubber composition at least once in the step of extruding the rubber composition to the downstream side; discharging a gas generated from the compressed rubber composition to outside of the cylinder; discharging, through a discharge outlet of the cylinder, the rubber composition after the gas has been generated; and molding the rubber composition that has been discharged through the discharge outlet into a predetermined rubber member shape.

An extruder screw for the plasticizing of at least one plastic material or a plastic material mixture, with a melting zone, a wave zone and a mixing zone arranged between the melting zone and the wave zone, wherein a conveying web extending in a helix-like manner along a screw longitudinal axis is formed in the melting zone and in the wave zone, wherein a conveying web of the melting zone terminates at an end of the melting zone facing the mixing zone, and a conveying web of the wave zone begins at an end facing the mixing zone. The application also relates to an extrusion device with this extruder screw, and a method for plasticizing at least one plastic material or a plastic material mixture.

To provide a rubber extruder capable of efficiently removing volatile components in unvulcanized rubber without decreasing productivity of the unvulcanized rubber. The rubber extruder 1 is for extruding the unvulcanized rubber (G) while kneading. It includes a barrel 2 having an input port 5 for introducing the unvulcanized rubber (G) and a discharge port 6 for discharging the unvulcanized rubber (G), a screw 3, which is arranged in the barrel 2, for extruding the unvulcanized rubber (G), and a vent 4 for sucking out air in the barrel 2. The screw 3 has a dam portion 7 which locally controls an extrusion amount of the unvulcanized rubber (G), a first screw portion 8 defined between the input port 5 and the dam portion 7, and a second screw portion 9 defined between the dam portion 7 and the discharge port 6. An effective screw length (L1) of the first screw portion 8 is 50% or more of a total effective screw length (L) of the screw 3.