ULTRAHIGH-MOLECULAR POLYETHYLENE SHEET AND PRODUCTION THEREOF.

摘要

An ultra high-molecular polyethylene sheet which is 100-300 micron thick and is prepd. by press-moulding a starting polyethylene (1) into a sheet. The polyethylene (1) is an ultra-high molecular polyethylene with a viscosity-average molecular wt. lying between 30,000 and 2,000,000 (preferred 800,000-1,500,000). (1) can be a mixt. of one or more high-molecular and low-molecular polyethylene. (1) Pref. contains inorganic materials. The polyethylene sheet has a fine uneven surface and is produced by press-moulding the starting polyethylene (1) using a screw presser. The screw-presser has an L/D ratio of 20-40 (where L is the length of flight and D is the diameter of the screw) and a coat hanger open angle of 120-170 deg.. The press-moulding sheet is rolled out along one axis with a compression ratio of 1.2-2.0. The screw comprises a feed zone, a compression zone and a metering zone.