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 increased in absorbency of a liquid and in 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 barrel including a return preventing member provided on an inner surface thereof, and the return preventing member satisfying at least one of specific parameters.

A method of recycling a mixed plastic waste comprising plastics having different melting temperatures includes conveying the mixed plastic waste through an extruder such that at least some of the higher melting point plastic is passes through the extruder without melting and is present in the extrudate as solid material.

A gear box for a reciprocating kneader. A primary rotational gear is attached to a gear box primary shaft and rotates in concert therewith. A secondary rotational gear is engaged with the primary rotation gear and rotates therewith. A secondary shaft is attached to the secondary rotational gear and rotates therewith. A primary oscillation gear is attached to the gear box primary shaft and rotates therewith. A secondary oscillation gear is rotationally engaged with the primary oscillation gear and rotates on the secondary shaft. An eccentric is coupled to the secondary oscillation gear and rotates in concert therewith. A yoke is engaged with the eccentric and oscillates on an axis perpendicular to the secondary shaft in response to the lobe. The gearbox secondary shaft moves along its axis in concert with yoke oscillation. A housing is pivotally attached to the yoke and pivotally attached to a casing at a casing.

A screw for a plasticating apparatus has one or more helical flights. A portion of the screw has a plurality of advancing grooves arranged in a noncontinuous helix cut in the screw. The advancing grooves are dimensioned to receive material therein as the material is conveyed through the barrel. The screw has a plurality of noncontinuous cross-cut grooves traversing one or more of the advancing grooves. The cross-cut grooves have a second helix angle greater than the first helix angle and less than ninety degrees; and/or one or more of the cross-cut grooves have a third helix angle of about ninety degrees.

Provided is a material supply device that supplies a material to a plasticizing unit, the plasticizing unit being configured to plasticize the material to generate a plasticized material, the material supply device including: a housing having an inlet through which the material is fed into the plasticizing unit, and accommodating the material; and a rotary member provided above the inlet in the housing and configured to rotate around a rotation shaft intersecting a vertical direction. The material is accommodated above the rotary member in the housing, and the material is intermittently supplied to the inlet by the rotation of the rotary member.

A mixer apparatus for the treatment of a polymer material to generate the Maxwell effect therein, at a rotor-stator interface in a mixer. The mixer comprises an alternating series of stators and rotors arranged along an elongated driveshaft supported within an elongated housing. The stators and rotors each having at least one helically arranged channel extending from an upstream end of the stator to an end location near the downstream end of that stator, those helically arranged channels preferably are arranged on the surface of the bore extending through the stator. A further generally radially directed channel from the end location of that helically arranged channel to a peripheral surface discharge at the downstream end of that stator is arranged to supply the polymer passing therethrough, to the upstream end of an adjacent rotor having a plurality of helically directed channels arranged on its outer periphery, those channels being inclined radially outwardly and of tapered dimension from an upstream end to a widened downstream end.

A method for producing a densified material includes: obtaining a film including at least one first layer of plastic material and one second layer with a composition distinct from the first layer, the first layer having a first melting temperature, or obtaining pieces of such a film; compressing the obtained film or the obtained pieces of film through at least one die of at least one extruder, and obtaining a profile of densified material, the extruder including at least one rotary endless screw pushing the obtained film or pieces of film along a screw axis; and optionally cutting the profile in order to obtain granules of densified material, the compression step being carried out at a maximum compression temperature for the obtained film or pieces of film, the maximum compression temperature being less than the first melting temperature. Also disclosed are installation and use of the densified material.

A screw for a plasticating apparatus has one or more helical flights. A portion of the screw has a plurality of advancing grooves arranged in a noncontinuous helix cut in the screw. The advancing grooves are dimensioned to receive material therein as the material is conveyed through the barrel. The screw has a plurality of noncontinuous cross-cut grooves traversing one or more of the advancing grooves. The cross-cut grooves have a second helix angle greater than the first helix angle and less than ninety degrees; and/or one or more of the cross-cut grooves have a third helix angle of about ninety degrees.

A method for producing a foam-molded product uses a producing apparatus including a plasticizing cylinder. The plasticizing cylinder has a plasticization zone, a starvation zone, and an introducing port which is formed in the plasticizing cylinder and via which a physical foaming agent is introduced into the starvation zone. The method includes: plasticizing and melting a thermoplastic resin into a molten resin in the plasticization zone; introducing a pressurized fluid containing the physical foaming agent having a fixed pressure into the starvation zone; allowing the molten resin to be in the starved state in the starvation zone; bringing the molten resin in the starved state into contact with the pressurized fluid having the fixed pressure in the starvation zone; and molding the molten resin into the foam-molded product. At least one pressure boosting part is provided in the starvation zone.

An mixing section for an extrusion screw has an inlet end and an outlet end as well as alternating wiping lands and barrier lands. The wiping lands have a greater helix angle than the barrier lands. The wiping lands and the barrier lands define inlet channels which narrow toward the outlet end and outlet channels which widen toward the outlet end. A helical pattern of mixing channels is cut into the wiping lands and the barrier lands. The mixing channels may be oriented generally at approximately right angles to the wiping lands and the barrier lands. A portion of the extrudate encounters the inside wall surfaces of the mixing channels and changes direction which improves the mixing of the extrudate.