VERFAHREN ZUR EXTRUSION EINES GEMISCHES

摘要

The extruder screw(2) has an internal bore(9) for temperature control fluid extending from the feed zone to the metering zone. Temperatures in the feed zone are held below the melting range of the thermoplastic with the lower melting point. In the metering zone the screw is heated to a temperature between the melting points of the two thermoplastics. Screw(2) temperatures in the feed zone are 20-60 degreesC and in the output zone 95-100 degreesC. The screw bore is divided into two chambers(9a,9b), the first extending from the feed zone to the first third of the melting zone and the second extending onwards to the metering zone. Temperature control fluids are heated in separate units. Both thermoplastics are preferably fed as granules, though pellets and powder are also possible.