A method and apparatus for a reciprocating kneader. A primary rotational gear is attached to a gear box primary shaft and rotates in concert therewith and engages a secondary rotational gear. The primary rotational gear drive provides a primary source of rotation for a kneading screw and for the secondary gear as a secondary source of rotation. An adjustable eccentric is coupled to the secondary oscillation gear and rotates in concert therewith for reciprocation motion.

A screw has a spiral blade for extruding and kneading a high-silica plastic elastomer containing not less than 100 phr of silica. The screw has a first section located on the most downstream side in the extrusion direction and provided with a barrier extending between the adjacent spiral blade threads, while inclining with respect to the screw axial direction. The length of the barrier is 1.5 to 3.0 times the lead length of the spiral blade in the first section. The height of the barrier is 2 to 10 mm lower than the height of the spiral blade. The barrier thickness is 0.9 to 3.0 times the height difference between the spiral blade and barrier.

A mixing section for an extrusion screw comprises a shaft having at least one set of spaced-apart cuspidate shaft teeth, with the shaft teeth extending radially outwardly from a root of the shaft. Each of the shaft teeth comprises a flank face and a rake face opposite the flank face, with the tooth transitioning between the flank face and the rake face at an outermost cusp. Some embodiments have one or more longitudinally extending, longitudinally spaced series of annular sets of circumferentially spaced shaft teeth. Some embodiments have one or more helically extending series of spaced-apart cuspidate shaft teeth. The mixing section may be received in a mixing section barrel to form a mixing portion of a screw extruder.

The extruder includes: a cylinder having a first end portion and a second end portion respectively formed at two ends of the cylinder in an axial direction, and an ejection port formed in the first end portion; a screw including a shaft that is configured to rotate within the cylinder, and a screw blade that is provided on an outer circumferential surface of the shaft; a supplier that is attached to the second end portion side of the cylinder and is configured to supply a kneading target to an inside of the cylinder; and a plurality of protruding members that protrude from an inner wall surface of the cylinder.

Provided is a water absorbent resin that is useful to sanitary materials such as a disposable diaper, a sanitary napkin, and a blood absorbent for medical use each having a higher liquid permeability and a higher water absorbing speed. Further provided is a water absorbent resin powder that is useful to sanitary materials such as a disposable diaper, a sanitary napkin, and a blood absorbent for medical use each having a smaller amount of return of a liquid and a higher heat retaining property. A gel grinding device to be used to produce a water absorbent resin, includes: a screw; a feed opening; an extrusion opening; a porous plate; and a barrel, the screw including: a rotating shaft; and a flight, and the screw satisfying at least one of specific parameters.

A worm shaft for a mixing and kneading machine in particular for continuous preparation processes, comprising a shaft rod, on the circumferential surface of which blade elements are arranged which are spaced apart from one another and which extend outward from the circumferential surface of the shaft rod, wherein the blade elements are arranged on the shaft rod, at least in one section extending in the axial direction of the worm shaft, in three rows extending in the axial direction of the worm shaft, wherein at least one of the blade elements of one of the rows is different from one of the blade elements of one of the other rows, and/or the rows of blade elements, viewed in cross-section of the shaft rod, are distributed irregularly over the circumference defined by the outer circumferential surface of the shaft rod, and wherein the angular distance between the midpoints M of the outer circumferential surfaces of the blade elements on the circumferential surface of the shaft rod of adjacent rows differs between at least two of the three rows of the at least other two rows, and including wherein, for example, each of the blade elements of the at least one section extending in the axial direction of the worm shaft has a longitudinal extension which extends in an angle of 45 to 135 to the axial direction of the worm shaft.

Disclosed is a device for processing plastic materials, having a shredding unit, a conveying unit having a screw (7), and an extruder, having at least one extruder screw (11), adjoining the screw, wherein the central longitudinal axis (3) of the screw (7) is oriented at an angle to the central longitudinal axis (10) of the extruder screw (11), in particular at an angle of 80 to 100, preferably 90, and the longitudinal axis (3) of the screw (7) is offset with respect to the longitudinal axis (10) of the extruder screw (11) by an offset (v) in the direction of the direction of rotation (12) of the extruder screw (11) at or in the region of the discharge opening (8) or the intake opening (16) of the conveying unit.

An improved rubber composition having improved extrudate properties and exhibiting superior tolerance to aging when subject to multi-step mixing process and in particular to a mixing process where the rubber composition is mixed in a first mixer, cooled by passing between a pair of cylinders, then mixed in a second mixer, the composition comprised of a disulfide silane.