An extruder comprising a housing having an inner recess; in which an extruder screw having a helical extruder screw flight is rotatably mounted. The outer diameter of the extruder screw is subdivided into a diameter start region, diameter central region, and diameter end region, wherein the diameter central region has a larger outer diameter than the other diameter regions, and a conical transition is formed in each case between regions at different diameters, and wherein at least one degassing zone formed in the diameter central region said degassing zone having a housing recess from which at least one suction opening extends to an outer side of the housing. The flow channel formed between the extruder screw shaft core and the inner wall of the housing recess is an annular expansion nozzle, wherein the outer diameter of the extruder screw flight is constant and the radial flow channel height increases.

An extruder for the viscosity-increasing preparation of meltable polymers, wherein an extruder screw with at least one helical extruder screw flight is positioned in a housing having an inner housing recess. A diameter central region has a larger outer diameter than at least one of the other diameter regions, and a conical transition is formed in each case between regions of different diameters. Two degassing zones are provided in the diameter central region, each of which has at least one associated suction opening in the housing, one degassing zone being designed in the region of the satellite screws and an additional degassing zone being designed upstream thereof in the flow direction. The thread depth of the screw threads, formed between the extruder screw flights is greater in both degassing zones than in at least one sealing and compression section formed therebetween.

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.

An extruder configured to extrude a solid raw material containing moisture includes a barrel, a hopper, a discharge port, and a slot portion, through which the inside and outside of the barrel communicate each other, is provided between the discharge port and the hopper; a screw, and a heater mounted on the barrel to heat the raw material. Raw material introduced into the barrel through the hopper is heated by the heater while being transferred within the barrel through the screw. A kneading zone, in which raw materials transferred by the screw threads are compressed, is formed on the screw. Since the raw material is melted within the barrel, a heating temperature of the heater and an axial rotation speed of the screw are controlled so that a sealing membrane that shields an inner transverse section of the barrel is formed from the liquid raw material in the kneading zone.

A conveyance portion, a barrier portion, and a path are provided at places of a screw main body in which a kneading portion is provided. In 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 to urge the raw materials having the conveyance limited by the barrier portion to increase pressure on the raw materials, to flow in the entrance. The raw materials flowing from the entrance flow through the path in the same direction as a conveyance direction of the conveyance portion.

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.

An extruder is disclosed including: a barrel; and a screw provided with a helical groove; wherein the screw comprises a dewatering portion comprising a first portion, and a second portion at a location downstream from the first portion; wherein, at the dewatering portion, clearance between the groove and the barrel decreases as one proceeds downstream; and wherein clearance reduction ratio at the first portion is greater than clearance reduction ratio at the second portion.

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.

An extruder screw conveying raw materials while kneading them includes a screw main body, conveyance portions, barrier portions, and paths. The conveyance portions convey the raw materials in an axial direction. The paths each include an entrance and an exit. 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 the same direction as a conveyance direction of the conveyance portions. The exit is opened in the outer circumferential surface of the screw main body at a position outside the conveyance portions in which the entrance is opened.

The present invention refers to the to the reuse of waste materials based on synthetic resins and, more specifically refers to the reuse of disposable diapers, plastic packaging (PVC, PP, PET, and so on), for the production of raw material for extrusion, lamination, injection and rotational molding processes, among others. The invention consists of a system comprising a chopper, a mill for homogenization of particle size, a disk compactor employing frictional heating between a fixed disk and a rotating disk and cooling means by circulation of cold water inside said discs.