A continuous process for making a pressure-sensitive adhesive is disclosed. A mixture comprising natural rubber having a Mooney viscosity of 85 to 100, a tackifier, a filler, and 0.1 to 5 wt. % of an added C.sub.12-C.sub.24 fatty acid based on the amount of mixture is masticated in a first section of a single- or twin-screw extruder. Mastication of the mixture continues in at least one subsequent extruder section in the presence of additional tackifier. The product is a homogeneous, reduced-viscosity pressure-sensitive adhesive. The minor proportion of added C.sub.12-C.sub.24 fatty acid aids mastication of the rubber and enables high throughput without addition of peptizers. Duct tapes made from the adhesives display improved adhesion to steel, better adhesion bond strength, and enhanced seven-day clean removability from even difficult substrates such as marble or ceramic tile.

A composite material and method of producing a composite material for use in fabrication, building and construction is disclosed. A composition as disclosed herein comprises a high proportion of particulate waste material dispersed in a matrix of thermoplastic polymer and wax. A method of producing a composite material comprises melt mixing thermoplastic polymer and wax with a particulate material, thereby dispersing the particulate material in a melt mixture of the composite material.

A method for obtaining and applying a sealing gasket element on a slide-valve sliding in a cavity of an apparatus for the recirculation and mixing of chemically reactive polymeric components, comprises the steps of: obtaining from an elastic-plastic material a precursor element of the seal element, with a grid structure having a reticular shape; positioning the precursor element around the slide-valve; exerting on the precursor element, through temporary clamping elements, a radial compression and contraction action to insert it and couple it to one or more housing seats provided on the slide-valve so as to obtain the seal element well coupled to the latter; progressively removing the clamping elements to sequentially release successive parts of the gasket element and gradually free the slide-valve to gradually introduce the parts of the slide-valve—freed in succession—in the housing cavity allowing the sealing gasket element to gradually expand radially due to the elastic return by adhering tightly to the inner surface of the same housing cavity. The special equipment for fitting the sealing gasket element on the slide-valve and the so obtained recirculation and mixing apparatus is also described.

In a method for reprocessing plastic waste material, in embodiments PET waste material, the plastic waste material is dried by a flash dryer in a conveying line and then fed into a multi-shaft screw machine. In the multi-shaft screw machine, the dried plastic waste material is reprocessed. Pre-drying enables simple, energy-efficient, economical, reliable and effective reprocessing.

In a method for reprocessing plastic waste material, in embodiments PET waste material, the plastic waste material is dried by a flash dryer in a conveying line and then fed into a multi-shaft screw machine. In the multi-shaft screw machine, the dried plastic waste material is reprocessed. Pre-drying enables simple, energy-efficient, economical, reliable and effective reprocessing.

Included is a homogeneous sheet, which excludes polyvinylchloride. The sheet includes a polyurethane, a synthetic rubber blend, and a filler. The synthetic rubber blend may include a pre-mix of a synthetic rubber and white oil.

An extruder system for degassing a mixture, comprising a first extruder, a second extruder arranged downstream of the first extruder and a transfer zone formed between these extruders, characterized by a pressure regulating device which can regulate the pressure at the outlet of the first extruder.

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 into a granulate of vulcanized rubber particles, C) extruding the vulcanized rubber particles produced in step B) in a twin-screw extruder to form a devulcanized rubber mixture, wherein, during the extruding in step C) at least one regeneration reagent is added to the extruded rubber particles, wherein the regeneration reagent comprises at least one silane, at least one plasticizer, at least one aging stabilizer or mixtures thereof. The invention also comprises an apparatus for performing the method and the uses of the apparatus, and a rubber mixture and also a pneumatic vehicle tyre or a technical rubber article comprising a component composed of the rubber mixture.

An extruder is provided with: a screw rotationally driven about the axis by a first motor; a barrel having a screw hole into which the screw is inserted and a de-airing port configured to discharge air inside the screw hole; a filter configured such that a part thereof faces the de-airing port of the barrel; and a filter-driving mechanism configured to move the filter to shift the part of the filter facing the de-airing port.

An extruder is provided with: a screw rotationally driven about the axis by a first motor; a barrel having a screw hole into which the screw is inserted and a de-airing port configured to discharge air inside the screw hole; a filter configured such that a part thereof faces the de-airing port of the barrel; and a filter-driving mechanism configured to move the filter to shift the part of the filter facing the de-airing port.