A single-screw extruder for conveying and plasticizing a meltable material, including a screw and a heated cylinder, wherein the screw is rotatably held in the heated cylinder, the screw has a core and a helical main flight, which is at a first distance from the internal wall of the cylinder, a region of a transition zone and a melting zone has at least two successive, non-overlapping barrier portions, and a cylinder-side outside flight surface of one or more overflow flights is chamfered in full or in part over a flight width such that a conical gap that gets narrower in an overflow direction is formed between the internal wall of the cylinder and the cylinder-side outside flight surface.

A screw has a spiral blade for extruding and kneading a high-silica plastic elastomer containing not less than 100 phr of silica. The screw has a first section located on the most downstream side in the extrusion direction and provided with a barrier extending between the adjacent spiral blade threads, while inclining with respect to the screw axial direction. The length of the barrier is 1.5 to 3.0 times the lead length of the spiral blade in the first section. The height of the barrier is 2 to 10 mm lower than the height of the spiral blade. The barrier thickness is 0.9 to 3.0 times the height difference between the spiral blade and barrier.

A screw has a spiral blade for extruding and kneading a high-silica plastic elastomer containing not less than 100 phr of silica. The screw has a first section located on the most downstream side in the extrusion direction and provided with a barrier extending between the adjacent spiral blade threads, while inclining with respect to the screw axial direction. The length of the barrier is 1.5 to 3.0 times the lead length of the spiral blade in the first section. The height of the barrier is 2 to 10 mm lower than the height of the spiral blade. The barrier thickness is 0.9 to 3.0 times the height difference between the spiral blade and barrier.

A continuous cycle system for moulding single objects from plastic material, including: an extruder including a cylinder extending along a longitudinal axis (L), a screw rotating inside the cylinder about the longitudinal axis (L), the screw having a core and a thread externally coupled to the core and heaters coupled to the cylinder; a moulding machine, configured to receive as input the flow of liquid plastic material from the extruder and including a plurality of moulds, each having a first and a second half mould movable relative to each other between an open position and a closed position.

A screw with a spiral blade for extruding a plastic elastomer while kneading the plastic elastomer, the screw includes a kneading region where the spiral blade is provided with cutout portions being configured to pass pins, and a plasticizing region being arranged on a downstream side in an extrusion direction of the kneading region. The plasticizing region includes a barrier extending between portions adjacently in the extrusion direction of the spiral blade.

A screw with a spiral blade for extruding a plastic elastomer while kneading the plastic elastomer, the screw includes a kneading region where the spiral blade is provided with cutout portions being configured to pass pins, and a plasticizing region being arranged on a downstream side in an extrusion direction of the kneading region. The plasticizing region includes a barrier extending between portions adjacently in the extrusion direction of the spiral blade.

The extruder includes: a cylinder having a first end portion and a second end portion respectively formed at two ends of the cylinder in an axial direction, and an ejection port formed in the first end portion; a screw including a shaft that is configured to rotate within the cylinder, and a screw blade that is provided on an outer circumferential surface of the shaft; a supplier that is attached to the second end portion side of the cylinder and is configured to supply a kneading target to an inside of the cylinder; and a plurality of protruding members that protrude from an inner wall surface of the cylinder.

Lower discharge temperatures and improved flow rates are obtained for the processing of meltable, solid crosslinkable compositions comprising a polymer, e.g., polyethylene, and a peroxide, in a single barrel extruder by equipping the extruder with an energy transfer (ET) screw that comprises: (1) an ET section with a distance averaged ET section depth of 8.0% to 10% of the extruder barrel internal diameter, and (2) a metering section with a metering section depth of 6.0% to 8% of the extruder barrel internal diameter.

Lower discharge temperatures and improved flow rates are obtained for the processing of meltable, solid crosslinkable compositions comprising a polymer, e.g., polyethylene, and a peroxide, in a single barrel extruder by equipping the extruder with an energy transfer (ET) screw that comprises: (1) an ET section with a distance averaged ET section depth of 8.0% to 10% of the extruder barrel internal diameter, and (2) a metering section with a metering section depth of 6.0% to 8% of the extruder barrel internal diameter.

Lower discharge temperatures and improved flow rates are obtained for the processing of meltable, solid crosslinkable compositions comprising a polymer, e.g., polyethylene, and a peroxide, in a single barrel extruder by equipping the extruder with an energy transfer (ET) screw that comprises: (1) an ET section with a distance averaged ET section depth of 8.0% to 10% of the extruder barrel internal diameter, and (2) a metering section with a metering section depth of 6.0% to 8% of the extruder barrel internal diameter.