MOLECULARLY ORIENTED MOLDED BODY OF ULTRA-HIGH- MOLECULAR-WEIGHT ETHYLENE/ALPHA-OLEFIN COPOLYMER

摘要

Disclosed is a molecularly oriented molded body of an ultra-high-molecular-weight ethylene/.alpha.-olefin copolymer having an intrinsic viscosity (?) of at least 5 d?/g and such a content of an .alpha.-olefin having at least 3 carbon atoms that the number of molecules of the .alpha.-olefin is 0.1 to 15 on the average per 1000 carbon atoms, wherein the molded body shows at least two crystal fusion endothermic peaks when the measurement is conducted in the restraint state by using a differential scanning calorimeter, the molded body has at least one crystal fusion endothermic peak (Tp) at a temperature higher by at least 20.degree.C than the inherent crystal fusion temperature (Tm) of the ultra-high-molecular-weight ethylene/.alpha.-olefin copolymer determined as the main fusion endothermic peak at the time of the second elevation of the temperature, and the quantity of heat based on said crystal fusion endothermic peak (Tp) is at least 15% based on the total fusion heat quantity.