Method and apparatus for manufacturing thermoplastic foam profiles.

摘要

In a process for mfg. a foamed thermoplastic elastomer (TPE) profile the polymer granular are extruded and at a melt temp. of 180 degrees C and 100-120 bar pressure just prior to a first high shear zone, 5 wt.% of H2O is injected into the barrel. The mixture is then subjected to one or more high shearing stages. In a mixing section between the high shear zones the mixture is intensively mixed and further mixing occurs in a mixing zone after the second shearing stage. Following temp. adjustment the mixture is extruded via a profiled die, foamed and cooled. Process appts. comprises an extruder with a granulate melting zone and shearing and homogenising zones. The shearing zone has two high shear screw secretions with a spacing 1-4 times screw dia. and forming the intensive mixing zone which includes a toothed rim . The homogenising zone included toothed discs perpendicular to the melt flow direction. A water injection valve enters the barrel prior to the first intensive shear section.