The invention relates to novel screw elements for multi-screw extruders with screw profiles co-rotating in pairs and being fully self-wiping in pairs, to the use of the screw elements in multi-screw extruders and to a process for extruding plastic compositions.

A wearing body or bushing having an axial twin borehole for receiving a twin screw for extruding meltable material, in particular plastic. In order to avoid cracking and to save material, the wearing body has a radial cross section with an outer contour, which is convexly curved over the entire circumference and is in the form of an oval, and with first and second axes of symmetry, which run perpendicularly to one another and define a point of intersection which lies on the extrusion axis. The width of the oval on the first axis of symmetry is greater than the height of the oval on the second axis of symmetry.

The present invention relates to screw elements with novel, tightly intermeshing, self-cleaning, co-rotating screw profiles for multishaft screw machines with pairs of co-rotating and fully abrading screw shafts, to the use of these screw elements in multishaft screw machines and to a method of generating these screw elements.

Disclosed herein are ethylene-based polymers having low densities and narrow molecular weight distributions, but high melt strengths for blown film processing. Such polymers can be produced by peroxide-treating a metallocene-catalyzed resin.

The present invention relates to a process for devolatilising polymer-containing media such as, in particular, polymer melts, polymer solutions and dispersions and also devolatilisation apparatuses for carrying out the abovementioned process.

A wax melt blank is produced with an extrusion process and intended to later be cut to length into individual wax melts. The wax melt blank includes at least about fifty percent by weight of wax, a fragrance, and up to about fifty percent by weight of a filler. The wax, the fragrance, and the filler are homogeneously dispersed within the wax melt blank.

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.

The present invention relates to new screw elements for multi-screw extruders with pairs of co-rotating and fully wiping screws.

An extruder is disclosed, and more particularly, to an integrated single screw extruder and a twin screw extruder for mixing, compounding, kneading and/or extruding of materials. The integrated extruder includes a first barrel assembly and a second barrel assembly. The integrated extruder further includes a first screw having a first threaded portion and a second threaded portion. The first threaded portion is housed within the first barrel assembly and is configured to provide upstream material processing. The second threaded portion is housed within the second barrel assembly and is configured to provide downstream material processing. The integrated extruder further includes a second screw having a non-threaded shaft portion and a threaded portion. The threaded portion of the second screw is housed within the second barrel assembly and is configured to provide the downstream material processing with the second threaded portion of the first screw.