MOLECULARLY ORIENTED MOLDED PRODUCT OF ULTRAHIGH-MOLECULAR WEIGHT ETHYLENE-ALPHA-OLEFIN COPOLYMER

摘要

PURPOSE:To obtain a molecularly oriented molded product of the titled copolymer, having a specific intrinsic viscosity and alpha-olefin comonomer content, plural and high endothermic peaks of crystal melting within a higher temperature region, excellent heat and creep resistance and useful as industrial textile materials, etc. CONSTITUTION:Ethylene and two or more alpha-olefins are polymerized as a slurry in n-decane as a polymerization solvent using a Ziegler based catalyst to provide a copolymer, which is then melt spun and drawn to afford the aimed molecularly oriented molded product having =5dl/g intrinsic viscosity [eta], average 0.1-15 alpha-olefin content based on 1,000 carbon atoms, propylene, butene-1, etc., as the first comonomer and =4C alpha-olefin as the rest comonomers, =2 endothermic peaks of crystal melting when measured in a restricted state thereof using a differential scanning calorimeter, =1 main endothermic peaks (Tp) of crystal melting at a temperature 20 deg.c higher than the original crystal melting temperature (Tm) obtained as the main endothermic peak of melting in the second heating and =15% quantity of heat based on the Tp for the total heat quantity of melting.