ULTRAHIGH-MOLECULAR-WEIGHT POLYETHYLENE MOLDING AND ITS PRODUCTION

摘要

PURPOSE:To obtain an ultrahigh-molecular-weight polyethylene molding excellent in resistances to heat and chipping abrasion (abrasion resistance) and useful as a sliding member by specifying its gel fraction. CONSTITUTION:The molding having a gel fraction of 10-70% and obtained by irradiating an ultrahigh-molecular-weight polyethylene molding with electron beams in a dosage of 2-20 Mrad. The polythylene is a polyethylene having an average molecular weight of 1000000 or above and an intrinsic viscosity [eta]of 6.5dl/g or above as measured in decalin at 135 deg.C. In order to lessen the dosage of electron beams and to heighten the cross-linking concentration, it is possible to add a polyfunctional monomer as a cross-linking promoter to the starting molding materials. The irradiation with electron beams is effective for also a molding made from a mixture of an ultrahigh-molecular-weight polyethylene, a lubricant and a reinforcement.