Methods for extrusion of polyolefins (110) that utilize melt temperature to control molecular weight and also reduce gels. Disclosed herein is an example method for controlling polymer chain scission in an extrusion system (100), comprising: melting a polyolefin resin (110) in extruder (102) at a first melt temperature to form a first melt (112); passing the first melt (112) through a screen pack (106); forming the first melt 112) into a first polyolefin product (116, 118); melting additional polyolefin resin (110) of the same grade in the extruder (102) at a second melt temperature to form a second melt (112), wherein the second melt temperature differs from the first melt temperature by 5° C. or more to control chain scission in the extruder (102); passing the second melt (112) through the screen pack (106); and forming the second melt (112) into a second polyolefin product (116, 118).

The present invention relates to a method for changing material in an extrusion device comprising at least two supply devices for supplying feedstock for an extruder, comprising the following steps: identifying a change request for changing the material in the extrusion device, preparing the supply devices for changing the material, separating at least two supply devices from the feed of feedstock to the extruder, discharging feedstock from the separated supply devices, filling subsequent material into the empty supply devices.

Provided is a production apparatus capable of producing a flexible tube whose hardness is naturally varied along the length direction thereof. This mixing valve includes: a first valve configured to distribute a first resin to a resin supply path and a resin discharge path; and a second valve configured to distribute a second resin to the resin supply path and the resin discharge path. In the mixing valve, the mixing proportion between the first resin and the second resin is increased or decreased in association with molding of the flexible tube, by changing a distribution ratio of the first resin in the first valve and a distribution ratio of the second resin in the second valve while keeping constant the total of the supply mounts of the first resin and the second resin supplied to a die.

The invention relates to a process for the production of articles, exemplarily a plastic article, by means of an extruder (1) to which a first plastic composition of a first main component and at least one associated minor component is supplied from a first group of dosing stations (21, 24). According to the invention, during the production time of a first production order there is prepared a second group of dosing stations (31, 33) at the extruder for a second production order for which a second plastic composition of a second main component and at least one associated minor component that is different from the first plastic composition has to be supplied to the extruder. After completion of the first production order it is reset to the second production order by terminating the supply of the first plastic composition by closing a first shut-off device (8) and starting the supply of the second plastic composition by opening a second shut-off device (8′).

A melt processing plant is provided that includes a melt charger for charging a processing head, in particular a pelletizing head, with melt, in which a diverter valve for discharging the melt during a starting and/or retooling phase is associated to the melt charger upstream of the processing head. A splitter divides the discharged melt into melt portions with the melt channels of the splitter head having at least one step-like cross-sectional enlargement of their inflow portion, a cross-sectional shape different from the outlet cross-section of the discharge channel, and an open orifice region out of the splitter.

The present invention relates to an overturning device (10) for overturning a molten material (200) in a melt channel (110) comprising a melt inlet (20) and a melt outlet (30) wherein between the melt inlet (20) and the melt outlet (30) at least one melt guidance means (40) is assembled for a rearrangement of the molten material (200) from the center (22) of the melt inlet (20) to the edge (34) of the melt outlet (30) and for rearrangement of the molten material (200) from the edge (24) of the melt inlet (20) into the center (32) of the melt outlet (30).

The present invention relates to an overturning device (10) for overturning a molten material (200) in a melt channel (110) comprising a melt inlet (20) and a melt outlet (30), wherein between the melt inlet (20) and the melt outlet (30) at least a melt guiding means (40) is assembled for a rearrangement of the molten material (200) from the centre (22) of the melt inlet (20) to the edge (34) of the melt outlet (30) and for a rearrangement of the molten material (200) from the edge (24) of the melt inlet (20) into the centre (32) of the melt outlet (30).

The present invention relates to an overturning device (10) for overturning a molten material (200) in a melt channel (110) comprising a melt inlet (20) and a melt outlet (30), wherein between the melt inlet (20) and the melt outlet (30) at least one melt guiding means (40) is assembled for a rearrangement of molten material (200) from the centre (22) of the melt inlet (20) to the edge (34) of the melt outlet (30) and for a rearrangement of molten material (200) from the edge (24) of the melt inlet (20) into the centre (32) of the melt outlet (30).

The present invention relates to an overturning device (10) for overturning a molten material (200) in a melt channel (110) comprising a melt inlet (20) and a melt outlet (30), wherein between the melt inlet (20) and the melt outlet (30) at least a melt guidance means (40) is assembled for a rearrangement of molten material (200) from the centre (22) of the melt inlet (20) at the edge (34) of the melt outlet (30) and for a rearrangement of molten material (200) from the edge (24) of the melt inlet (20) in the centre (32) of the melt outlet (30).

The present invention relates to an overturning device (10) for overturning a molten material (200) in a melt channel (110) comprising a melt inlet (20) and a melt outlet (30), wherein between the melt inlet (20) and the melt outlet (30) at least a melt guidance means (40) is assembled for a rearrangement of molten material (200) from the centre (22) of the melt inlet (20) to the edge (34) of the melt outlet (30) and for a rearrangement of molten material (200) from the edge (24) of the melt inlet (20) into the centre (32) of the melt outlet (30).