An extruder and a long fiber thermoplastic (LFT) extrusion member manufactured thereby, and the extruder uses the LFT as a raw material to produce LFT extrusion members such as LFT sheets, pipes and profiles by a continuous extrusion molding process. The structural improvement of the extruder screw, including the screw body having three different thread groove deep sections, in sequence, a feed section, a compression section and a metering section, so that the LFT extrusion member produced by the extruder has high strength, high stiffness, high dimensional stability, low warpage and resistance to creep.

An extruder and a long fiber thermoplastic (LFT) extrusion member manufactured thereby, and the extruder uses the LFT as a raw material to produce LFT extrusion members such as LFT sheets, pipes and profiles by a continuous extrusion molding process. The structural improvement of the extruder screw, including the screw body having three different thread groove deep sections, in sequence, a feed section, a compression section and a metering section, so that the LFT extrusion member produced by the extruder has high strength, high stiffness, high dimensional stability, low warpage and resistance to creep.

A counter-rotating differential speed extrusion device includes a barrel and a screw mechanism in the barrel comprising a first and second screws. A crest diameter and a root diameter of the first screw are respectively meshed with that of the second screw; the first and second screws counter-rotate in differential speeds at a fixed rotation speed ratio; at least one first intermediate circular arc structure with a trend consistent with that of the crest diameter and the root diameter of the first screw is provided between the root diameter and the crest diameter of the first screw, a second intermediate circular arc structure tangent to the first intermediate circular arc structure and having a trend consistent with that of the root diameter and the crest diameter of the second screw is provided between the root diameter and the crest diameter of the second screw.

A counter-rotating differential speed extrusion device includes a barrel and a screw mechanism in the barrel comprising a first and second screws. A crest diameter and a root diameter of the first screw are respectively meshed with that of the second screw; the first and second screws counter-rotate in differential speeds at a fixed rotation speed ratio; at least one first intermediate circular arc structure with a trend consistent with that of the crest diameter and the root diameter of the first screw is provided between the root diameter and the crest diameter of the first screw, a second intermediate circular arc structure tangent to the first intermediate circular arc structure and having a trend consistent with that of the root diameter and the crest diameter of the second screw is provided between the root diameter and the crest diameter of the second screw.

A self-cleaning extruding apparatus with two co-rotating screws and the method thereof are provided here. Said apparatus is comprised of a screw mechanism, a barrel (1), a feeding port (10), a venting port (11), and a discharge port (12). Said screw mechanism is comprised of the first screw with one tip (3) and the second screw with two tips (4). There is a baffle in the channel of the first screw and the baffle's height is lower than that of the screw flight. The baffle will cause hyperbolic perturbation in the shape of a ‘figure 8’ flow pattern above the top of the baffle. The first and second screws rotate at the same speed and touch each other at all times, thereby achieving a self-cleaning function.

The baffle will generate chaotic mixing in the screw channel caused by the hyperbolic perturbation. Topological chaos is also introduced into the screw channel by the mechanism ‘one part divided into two parts, then two parts converging into one part, and then one part divided into two parts once more’. Each of the screws in the present invention uses an asymmetrical flow channel geometrical shape, such that a periodic action like ‘compression—expansion—further compression—expansion further’ works. The above three enhancement mechanisms work together to efficiently accelerate melting and mixing.

The invention relates to a process for extruding plastic compositions. The process in particular relates to the conveying, kneading and/or mixing of plastic compositions, in particular of polymer melts and mixtures of polymer melts, above all thermoplastics and elastomers, particularly preferably polycarbonate and polycarbonate blends, also with the incorporation of other substances such as for example solids, liquids, gases or other polymers or other polymer blends.

A 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.

A plasticating screw is proposed, with a screw channel, which runs spirally around a screw core, is laterally delimited by a flight (1), (2) and has flow elements (3), (4) that are distributed over its longitudinal direction, extend transversely over the screw channel and comprise a deep section (5) and a compression section (6), rising radially in the longitudinal direction. In order to design a plasticating screw of the type mentioned at the beginning in such a way that its length is reduced and good melting characteristics can be achieved even with little energy input, it is proposed that the compression section (6) forms at least one run-up surface (7), which is inclined towards the flight (1), (2) and is adjoined in the longitudinal direction by a plateau (8) for forming the flow.

A plasticating screw is proposed, with a screw channel, which runs spirally around a screw core, is laterally delimited by a flight (1), (2) and has flow elements (3), (4) that are distributed over its longitudinal direction, extend transversely over the screw channel and comprise a deep section (5) and a compression section (6), rising radially in the longitudinal direction. In order to design a plasticating screw of the type mentioned at the beginning in such a way that its length is reduced and good melting characteristics can be achieved even with little energy input, it is proposed that the compression section (6) forms at least one run-up surface (7), which is inclined towards the flight (1), (2) and is adjoined in the longitudinal direction by a plateau (8) for forming the flow.

The present invention relates to a multishaft extruder having screw shafts that rotate in the same sense and at the same speed, wherein these screw shafts each have at least one region having a special arrangement of screw elements, wherein the screw elements have an asymmetrical cross-sectional screw profile. In this case, these in each case at least one regions are situated directly opposite on directly adjacent screw shafts. The present invention also provides for the use of the extruder of the invention for processing or production of plastic or viscoelastic masses.