| 摘要 |
PURPOSE:A finely porous, uniform, thin, and high-strength film having a large number of fine through holes with a narrow distribution, by drawing ultra-high- molecular-weight olefin gel in a high draw ratio. CONSTITUTION:A finely porous membrane consisting of an alpha-olefin polymer having >=5X10<5>, preferably 1X10<6>-15X10<6> alpha-olefin polymer, having through holes with 0.01-1mum average pore diameter and 30-90% void, stretched twice, preferably 5-20 times, drawn <=10 times, preferably 25-200 times in face draw ratio. Polypropylene is used as the alpha-olefin. Gel molded from a solution of the alpha-olefin polymer is subjected to solvent removal treatment, the alpha-olefin polymer carried in the gelatinous molded article is adjusted to a fixed amount and the molded article is drawn, to remove the remaining solvent. The amount of the solvent removed from the gelatinous molded article is at least 10wt%, and the amount of the alpha-olefin polymer contained in the gelatinous molded article is 10-90wt%. |
