Improvements in the extrusion of thermohardenable materials are achieved by cooling the material in the initial zone of the extruder and reducing residence time by use of a prescribed length to diameter ratio and screw speed, particularly useful for intermittent application during robotically controlled mass production.

Improvements in the extrusion of thermohardenable materials are achieved by cooling the material in the initial zone of the extruder and reducing residence time by use of a prescribed length to diameter ratio and screw speed, particularly useful for intermittent application during robotically controlled mass production.

The invention relates to a process for devulcanizing a vulcanized rubber mixture, comprising the following steps: A) providing or producing a vulcanized rubber mixture, B) comminuting the vulcanized rubber mixture to a granular material composed of vulcanized rubber particles, where the vulcanized rubber particles have a maximum particle diameter of 100 mm, C) extruding the vulcanized rubber particles produced in step B) in a twin-screw extruder at a shear rate of less than 100 s.sup.−1, where the temperature of the vulcanized rubber particles during extrusion is less than 200° C., to give a devulcanized rubber mixture having a temperature above 100° C., D) cooling the devulcanized rubber mixture in a further kneading unit, so as to give a devulcanized rubber mixture having a temperature in the range from 50° C. to 100° C. The invention further relates to an apparatus for performing the process and to the use of the apparatus for devulcanization of a vulcanized rubber mixture.

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.

It is provided an extruder for a system for the additive manufacture of freely formable metal parts with or without a supporting structure by means of an extrusion method from a composite material, which is arranged on a three-dimensionally movable kinematic mechanism, with a building platform. The extruder consists of a housing and a screw arranged in the housing. The extruder is provided with a mechanical drive for the composite material to be extruded, with an exchangeable nozzle, arranged on the housing, and the housing is connected to the mechanical drive by way of suitable means for transporting the composite material.

It is provided an extruder for a system for the additive manufacture of freely formable metal parts with or without a supporting structure by means of an extrusion method from a composite material, which is arranged on a three-dimensionally movable kinematic mechanism, with a building platform. The extruder consists of a housing and a screw arranged in the housing. The extruder is provided with a mechanical drive for the composite material to be extruded, with an exchangeable nozzle, arranged on the housing, and the housing is connected to the mechanical drive by way of suitable means for transporting the composite material.

The present invention discloses a method for preparing high-melt-strength polylactide resin by two-step reaction, which comprises the following steps: mixing polylactide resin and GMA to obtain a premix; mixing multifunctional reactive monomer, a peroxide initiator and organic solvent to obtain a monomer mixture; and adding the premix and the monomer mixture into a screw extruder in sections, after melting, blending, extruding, cooling, pelletizing and drying to obtain a high melt strength polylactide resin. The method of the present invention has a simple production process, can be adapted to large-scale industrial production, the graft modification reaction is rapid and controllable, and the obtained product is safe without residue and high in purity. The high-melt-strength polylactide resin has a low melt flow index, high complex viscosity and storage modulus, and is a green polymer material with wide application prospects.

A planetary extruder for producing and processing polymers includes a degassing section. The extruder includes a housing and a bushing arranged therein. The bushing has an internal toothing with a pitch diameter and a root circle. An externally toothed central spindle is arranged within the housing. Planetary spindles rotate about the central spindle between the central spindle and the bushing. A heat transfer fluid is guided through fluid channels which extend helically along an outer surface of the bushing and guide the heat transfer fluid axially. A degassing opening is provided to which a negative pressure is applied for degassing. A minimum radial thickness (t) of the bushing between the root circle of the internal toothing on an inside of the bushing and a bottom of the fluid channels on an outside of the bushing is selected based on the pitch diameter (d) of the internal toothing.

A planetary extruder for producing and processing polymers includes a degassing section. The extruder includes a housing and a bushing arranged therein. The bushing has an internal toothing with a pitch diameter and a root circle. An externally toothed central spindle is arranged within the housing. Planetary spindles rotate about the central spindle between the central spindle and the bushing. A heat transfer fluid is guided through fluid channels which extend helically along an outer surface of the bushing and guide the heat transfer fluid axially. A degassing opening is provided to which a negative pressure is applied for degassing. A minimum radial thickness (t) of the bushing between the root circle of the internal toothing on an inside of the bushing and a bottom of the fluid channels on an outside of the bushing is selected based on the pitch diameter (d) of the internal toothing.

The present invention relates to a method for continuously manufacturing UHMWPE products comprising:—providing a counter-rotating twin-screw extruder;—feeding UHMWPE powder into a hopper of said counter-rotating twin-screw extruder;—transporting said UHMWPE powder from said hopper through said counter-rotating twin-screw extruder to an outlet of said counter-rotating twin-screw extruder;—further transporting said UHMWPE powder from said outlet of said counter-rotating twin-screw extruder to an entrance of a heat-controlled tooling system for defining the shape of UHMWPE products;—withdrawing said UHMWPE products from an outlet of said heat-controlled tooling system.