| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a laminate fine porous film, which can obtain the laminate fine porous film excellent in balance of a good gas permeability and a film-thickness uniformity even if a strain velocity in a hot stretching process is increased. SOLUTION: The method of manufacturing the laminate fine porous film (wherein T<SB>mB</SB>represents a melting point (°C) of a resin composition B) includes the following processes (1) and (2): (1) a cold stretching process of cold stretching a laminate having a film A constituted by a resin composition A and a film B constituted by a resin composition B having a lower melting point than that of the resin composition A at least in one direction 1.05-2.0 times in a state of holding≥-20°C and≤(T<SB>mB</SB>-60)°C, and (2) a hot stretching process of hot stretching the laminate cold-stretched in the process (1) at least in one direction at the strain velocity≥100%/min and≤1,000%/min,≥1.05 times and≤5.0 times in a state of holding≥(T<SB>mB</SB>-60)°C and <(T<SB>mB</SB>-30)°C. COPYRIGHT: (C)2010,JPO&INPIT |
