| 摘要 |
PROBLEM TO BE SOLVED: To freely and simply manufacture a porous film having a desired average pore diameter only by changing a stretching temperature without affecting performance other than pore diameters. SOLUTION: In a method for manufacturing the porous film including a process in which a composition containing a thermoplastic resin and a plasticizer, after being melted, kneaded, and dispersed uniformly, is cooled and solidified into a molding, the plasticizer is removed to form a porous molding, and the porous molding is stretched, after a porous film of an average pore diameter d1 is produced by stretching the porous molding a specified temperature, a stretching temperature when a porous film of an average pore diameter d2 is produced is selected so that the coefficient of a degree of freedom defined by the average pore diameter and the stretching temperature is within a specified range. |
