PRODUCTION OF HARDWEARING AND SHOCK-RESISTANT EXTRUDATES OF ULTRA-HIGH MOLECULAR WEIGHT POLYETHYLENE AND APPARATUS FOR THIS PURPOSE

摘要

For the production of extrudates of ultra-high molecular weight polyethylene, finely divided polyethylene or polyethylene powder is introduced into the cooled feed zone of a single-screw extruder and compressed therein, melted in a transport zone of the extruder and discharge with shaping of the extrudate and cooling. The polyethylene is processed in the transport zone using a velocity gradient of from 50 to 1,000 sec-1 in the radial play between the screw and the extruder barrel, heated to 180 DEG -280 DEG C. and then transferred to a screw-free zone in which final shaping of the extrudate is effected.