A method of continuously manufacturing a cured membrane includes continuously compounding and mixing a vulcanizable rubber composition in a mixing extruder while continuously removing gasses from the vulcanizable rubber composition during mixing with a vacuum. The vulcanizable rubber composition may be continuously extruded to form an extrudate, which may be continuously calendered to form a green membrane. The green membrane may be continuously cured, such as by a hot air conveyor curing system, to form a cured membrane.

A method of continuously manufacturing a cured membrane includes continuously compounding and mixing a vulcanizable rubber composition in a mixing extruder while continuously removing gasses from the vulcanizable rubber composition during mixing with a vacuum. The vulcanizable rubber composition may be continuously extruded to form an extrudate, which may be continuously calendered to form a green membrane. The green membrane may be continuously cured, such as by a hot air conveyor curing system, to form a cured membrane.

An element for a counter-rotating twin screw processor is disclosed. The element has an axial bore for mounting on a screw shaft of the processor. The element or a portion of the element comprises a continuous self-wiping flight helically formed thereon. Further, the element comprises one or more lobes with a lobe profile that is defined in a radial plane of the element and is provided by a functionally continuous curve obtained by combining a first curve to a second curve. The second curve is a mirror-image of the first curve about a radial axis passing through a central axis of the element and one of two extreme points of the first curve. The first curve is represented by a mathematical expression.

Processes for decrosslinking crosslinked plastic and devulcanizing vulcanized rubber include advancing such materials through single screw or twin screw extruders including special ultrasonic treatment zones wherein threadless shaft (single screw) or shafts (twin screw) rotate under an ultrasonic horn having a distal end aligned with the shaft or shafts and being shaped complimentary thereto. Special arcuate (single screw) or double-arcuate ultrasonic treatment flow paths confine the materials to flow under the horn where the material is subjected to ultrasonic waves to decrosslink the material, in the case of crosslinked plastic, or devulcanize the material, in the case of vulcanized rubber, with the extrudate leaving the die as a continuous stream or rope as is typical of virgin plastic or rubber.

Processes for decrosslinking crosslinked plastic and devulcanizing vulcanized rubber include advancing such materials through single screw or twin screw extruders including special ultrasonic treatment zones wherein threadless shaft (single screw) or shafts (twin screw) rotate under an ultrasonic horn having a distal end aligned with the shaft or shafts and being shaped complimentary thereto. Special arcuate (single screw) or double-arcuate ultrasonic treatment flow paths confine the materials to flow under the horn where the material is subjected to ultrasonic waves to decrosslink the material, in the case of crosslinked plastic, or devulcanize the material, in the case of vulcanized rubber, with the extrudate leaving the die as a continuous stream or rope as is typical of virgin plastic or rubber.

A continuous kneading device (1) includes a pair of kneading rotors (3), being capable of increasing mesh between the kneading rotors (3) while suppressing a kneading load applied to the kneading rotors (3). The continuous kneading device (1) includes a barrel (2) and a pair of kneading rotors (3) housed in the barrel (2) and rotating in mesh in directions different from each other. Each kneading rotor (3) includes a plurality of kneading flights (11, 15) for kneading a material supplied into the barrel (2). The kneading flights (11, 15) and respective portions of the barrel (2) housing the kneading flights (11, 15) respectively configure a plurality of kneading sections aligned axially of the kneading rotors (3). The material is fed axially from the upstream kneading section to the downstream kneading section to be sequentially kneaded. The kneading flight (15) constituting the downstream kneading section has a rotational outer diameter (D2) larger than a rotational outer diameter (D1) of the kneading flight (11) constituting the upstream kneading section.

A method for extruding thermoplastic molding compounds, the production of thermoplastic molding compounds taking place in a screw machine with mechanical dewatering, and impact-modified molding compounds or polymer blends which contain impact-modified thermoplastic materials that were produced by means of the method according to the invention.

A method for the improved extrusion of polyethylene polymers comprising passing polyethylene through a single stage, twin screw extruder comprising a solid polymer conveying zone, a polymer melting zone, a dispersive mixing zone, and a distributive mixing/pumping zone, in which the throughput and screw speed are optimized to reduce the number of gels present, ensure complete polymer melting within the polymer melting zone, and to minimize polymer degradation.

The present invention relates to a process for the production of a panel for floor or wad coverings comprising the steps of mixing and homogenising raw materials, thereby obtaining a dryblend, extruding said dryblend, thereby obtaining one or more thermoplastic layers, laminating the afore-mentioned thermoplastic layers, thereby obtaining a laminate, and profiling said laminate, thereby obtaining a panel for floor or wall coverings, wherein at least one thermoplastic layer is extruded by means of a co-rotating twin-screw extruder with pressure element.

The invention describes a method for the manufacture of a plasticised polyvinyl alcohol polymer mixture, the method comprising the steps of: introducing a polyvinyl alcohol polymer comprising at least 98 wt % polyvinyl alcohol or a blend of the polymer into a mixing reactor; wherein the mixing reactor comprises a blending chamber having a primary inlet, a primary outlet and at least two inter-engaging components extending between the primary inlet and primary outlet, the components being arranged to apply a shearing force to the polymer while the polymer is conveyed by the components from the inlet through a reaction zone to the outlet; one or more secondary inlets located downstream from the primary inlet for introducing reactants comprising a processing agent and a plasticiser to the chamber to form a reaction mixture; wherein the blending chamber comprises a plurality of heated regions arranged so that the mixture is subjected to a controlled temperature profile; a secondary outlet located between the reaction zone and primary outlet arranged to allow removal of processing agent from the chamber; reacting a reaction mixture comprising the processing agent, plasticiser and polymer in the reaction zone to form plasticised polymer; wherein when the processing agent is water the amounts of water is from 3 wt % to 18 wt %; and allowing the plasticised polymer to pass from the primary outlet.