| 摘要 |
A porous thermoplastic resin film (15) has micropores formed from a three-dimensional network made of trunk fibrils extending in one direction, and branch fibrils through which trunk fibrils are connected to one another. Density of branch fibrils is higher than that of trunk fibrils. Average pore diameter and radius of micropores satisfy a predetermined relation. A porous thermoplastic resin film has micropores formed from a three-dimensional network made of trunk fibrils extending in one direction, and branch fibrils through which trunk fibrils are connected to one another. The density of branch fibrils is higher than that of trunk fibrils. Average pore diameter (d) (in Microm) of micropores determined by bubble-point method ASTM F316-86 and radius (r) (in Microm) of micropores determined by mercury porosimetry JIS K1150 satisfy the relationship 1.2 = 2r/d = 1.7. |
