Stretch molded article of ultra high molecular weight ethylene / α-olefin copolymer having high breaking energy and method for preparing the same

摘要

PURPOSE:To obtain the titled formed article having high breaking energy and strength from a high-concentration dope in high efficiency, by extruding a dope of a specific ultra-high molecular weight ethylene.alpha-olefin copolymer in flowing state and drawing the extrudate by a specific method. CONSTITUTION:A dope is produced by compounding 85-20pts.wt. of a diluent to 15-80pts.wt. of an ultra-high molecular weight ethylene.alpha-olefin copolymer having an intrinsic viscosity [eta] of =5dl/g and containing 0.2-5mol.% of =4C alpha-olefins. The dope is extruded through a nozzle of a forming die at a temperature capable of maintaining the fluid state. The extrudate is taken up at a draft ratio of =3 and the ultra-high molecular weight ethylene.alpha-olefin copolymer is crystallized. The obtained preparatorily drawn and oriented product is drawn at a draw ratio of =3 to obtain the objective formed article having an orientation degree of =0.93 (calculated from the half value weight of X-ray diffraction pattern) and a breaking energy of =80J/g (determined as an integrated value of the breaking point of a stress-strain curve).