At a part of the screw main body at which the kneading portion is provided, conveyance portions, a barrier portion and a path are provided at a plurality of places. At least one of the places, the path is provided inside the screw main body, and includes an entrance and an exit. The entrance is opened in such a manner that the raw material whose pressure is enhanced by being restricted in conveyance by the barrier portion flows into the entrance. The path is formed in such a manner that the raw material flowing into the path from the entrance flows toward the exit in a direction opposite to the direction of conveyance.

A kneading method includes conveying a raw material along a conveyance path; and increasing the raw material in pressure by restricting a conveyer from conveying the raw material by a barrier, causing the raw material with an increased pressure to flow into a passage from an inlet located at the conveyer, circulating the raw material having flowed into the passage to an outlet in the same direction as the conveying direction of the conveyer, and causing the raw material having circulated in the passage to flow out from the outlet to the outer circumference of a screw body. The raw material includes a polypropylene-based resin composition containing polypropylene and olefin rubber.

A conveyance portion, a barrier portion, and a path are provided at places of a portion of a screw main body in which a kneading portion is provided. In at least one of the places, an entrance is opened to cause raw materials, conveyance of which is limited by a barrier portion to increase pressure on the raw materials, to flow in. The raw materials flowing in from the entrance flow through the path in the opposite direction to a conveyance direction of the conveyance portion. An exit is opened in an outer circumferential surface of the screw main body at a position outside the conveyance portion in which the entrance is opened.

Method for manufacturing a composite material, comprising the following steps: a) plasticizing a binder in an extruder, wherein the binder comprises a polymer; b) providing a mixture of a cellulosic material and a hydrophobic agent dissolved and/or dispersed in a liquid carrier; c) mechanically shearing and drying the mixture in an extruder whereby liquid is at least partly extracted from the mixture or is not present in liquid form anymore; and d) blending the dried mixture with the plasticized binder.

A method for manufacturing a heat resistant resin composition having superior dispersibility of maleimide-based copolymer, the method including: a melt-kneading step to melt and knead a maleimide-based copolymer (A) and at least one resin (B) selected from the group consisting of ABS resin, ASA resin, AES resin, and SAN resin with an extruder; wherein: a ratio of a melt viscosity of the maleimide-based copolymer (A) with respect to a melt viscosity of the resin (B) obtained with a shear rate of 120/sec and a cylinder temperature of a kneading unit of the extruder is 1.0 or higher and lower than 3.4, is provided.

An extruder screw includes a screw main body, conveyance portions, barrier portions, and paths. The raw materials, the conveyance of which is limited by the barrier portions, flow in from the entrance. The raw materials flowing in from the entrance flow through the paths in an opposite direction to a conveyance direction of the conveyance portions. The exit is opened in the outer circumferential surface of the screw main body at a position on an upstream side in the conveyance direction in the conveyance portions in which the entrance is opened.

An extruder screw for a multi-screw extruder, having an intake and metering section. A rotor body has an enlarged diameter relative to the intake and metering section and has a plurality of satellite screws positioned on the outer periphery of the rotor body at least over part of the length thereof. A cone and an adjoining drive zone are formed between the intake and metering section and the rotor body, in which drive zone the satellite screws each engage via a drive pinion in an external toothing on the rotor body or in an internal toothing on a stator ring or in the inner wall of an extruder housing. At least one peripherally closed flow channel is formed, which flow channel extends from an inlet opening on the cone to an outlet opening located downstream of the drive pinions in the direction of flow.

A conveyance portion, a barrier portion, and a path are provided at places of a portion of a screw main body in which a kneading portion is provided. In at least one of the places, an entrance is opened to cause raw materials, conveyance of which is limited by a barrier portion to increase pressure on the raw materials, to flow in. The raw materials flowing in from the entrance flow through the path in the opposite direction to a conveyance direction of the conveyance portion. An exit is opened in an outer circumferential surface of the screw main body at a position outside the conveyance portion in which the entrance is opened.

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 mixing and extrusion machine (10) for the manufacture of rubber mixtures has a mixer with a converging conical twin screw (12) with a fixed frame (14) that supports sleeves (16). Two screws (18), being mounted at an angle, are mounted in the mixer (12) so as to move in translational movement between an opening (22) arranged upstream and an outlet (25) arranged downstream of the sleeves, so that the thread tips of each screw contact tangentially the surfaces of the opposite screw so that the screws remain substantially in contact with each other when the screws rotate at an angle and at a center distance that facilitates self-cleaning. The screw threads maintain tangential contact with the inner surfaces of the sleeves, thus preventing the retention of mixing material on these surfaces.