| 摘要 |
PURPOSE:To obtain an amorphous polyolefin film having especially excellent optical properties, dimensional stability and mechanical strength by compounding an amorphous polyolefin polymer having high molecular weight with a specific amount of an amorphous polyolefin polymer having low molecular weight. CONSTITUTION:The objective film having a thermal shrinkage of <=0.5% (100 deg.C, 30min), a thermal shrinkage difference between longitudinal and lateral directions of <=0.1%, a birefringence of <=0.005 and an impact strength of >=1.1 kg.cm/mm<2> can be produced by compounding (A) one or more kinds of amorphous polyolefin polymer selected from hydrogenation product of ring-opened polymer of dicyclopentadiene, hydrogenation product of a copolymer of dicyclopentadiene and ethylene, etc., and having high molecular weight (the number-average molecular weight is 35,000-70,000, preferably 40,000-60,000) and (B) an amorphous polyolefin polymer having essentially the same structure as the component A and having low molecular weight (the number-average molecular weight is 10,000-32,000) at a weight ratio (A:B) of 99:1 to 40:60, preferably 95:5 to 40:60 and extrusion molding the mixture in molten state. |
