MANUFACTURE FOR ANTI-WEAR, SHOCK- RESISTANT EXTRUDED ITEM OF SUPER MOLECULAR WEIGHT POLYETHYLENE AND APPARATUS THEREFOR

摘要

PURPOSE: To obtain a high production speed by a single-screw extruder by heating a powder of ultra-high mol.wt. polyethylene to a specific temp. range in the feed zone of an extruder to form an extrusion molded object and cooling the surface temp. of the molded object so as to make the same lower than specific temp. CONSTITUTION: A fine particulate powder of ultra-high mol.wt. polyethylene (UHMW- PE) having a standiger structural unit index of about 800-3,500 cm3 /g is fed to the cooled feed zone of a single-screw extruder and heated to a temp. of 180-280 deg.C while compressed in the feed zone 6 of the extruder to be transferred to a screw-free zone 7 to form an extrusion molded object and this molded object is cooled so that the surface temp. thereof becomes lower than 150 deg.C. The shearing force controlled between the screw 3 and barrel 1 of the feed zone of the extruder is applied to OHMW-PE. It is most pref. to set a speed gradient to 50-1,000 s-1 corresponding to the kind and output of OHMW-PE to be treated. By this constitution, the stable feed characteristics and high feed efficiency, for example, of 25% or more of the extruder can be realized.