Abstract: A method for processing polycondensates, wherein the material in the form of granules or recyclate is processed to form a melt, the method including the following steps: a) feeding the material into a vacuum lock where the material is held below atmospheric pressure; b) conveying the material from the vacuum lock into a first extruder having a filling region and a feed zone that are held below atmospheric pressure, wherein the material is at least partially melted in the first extruder; c) conveying the melted material from the first extruder into a second, twin-screw extruder with two screws that turn in the opposite direction. The second extruder has at least one degassing zone and a metering zone that follows in the conveying direction. The melted material is degassed in the degassing zone and the melted material is pressurized in the metering zone and is output out of the second extruder.

Abstract: A plasticating screw is proposed, with a screw channel, which runs spirally around a screw core, is laterally delimited by a flight (1), (2) and has flow elements (3), (4) that are distributed over its longitudinal direction, extend transversely over the screw channel and comprise a deep section (5) and a compression section (6), rising radially in the longitudinal direction. In order to design a plasticating screw of the type mentioned at the beginning in such a way that its length is reduced and good melting characteristics can be achieved even with little energy input, it is proposed that the compression section (6) forms at least one run-up surface (7), which is inclined towards the flight (1), (2) and is adjoined in the longitudinal direction by a plateau (8) for forming the flow.

Abstract: A plasticating screw is proposed, with a screw channel, which runs spirally around a screw core, is laterally delimited by a flight (1), (2) and has flow elements (3), (4) that are distributed over its longitudinal direction, extend transversely over the screw channel and comprise a deep section (5) and a compression section (6), rising radially in the longitudinal direction. In order to design a plasticating screw of the type mentioned at the beginning in such a way that its length is reduced and good melting characteristics can be achieved even with little energy input, it is proposed that the compression section (6) forms at least one run-up surface (7), which is inclined towards the flight (1), (2) and is adjoined in the longitudinal direction by a plateau (8) for forming the flow.

Abstract: The invention relates to a measuring nozzle for determining the extensional viscosity of polymer melts during their processing, comprising a flow channel which has a rectangular cross-section and which has a transitional section (3) between an inlet section (1) and an outlet section (2) with respective constant cross-section, which transitional section tapers hyperbolically in the flow direction (8) between two mutually opposite channel walls (6 and 7).

Abstract: The invention relates to a measuring nozzle for determining the extensional viscosity of polymer melts during their processing, comprising a flow channel which has a rectangular cross-section and which has a transitional section (3) between an inlet section (1) and an outlet section (2) with respective constant cross-section, which transitional section tapers hyperbolically in the flow direction (8) between two mutually opposite channel walls (6 and 7).