| 摘要 |
PROBLEM TO BE SOLVED: To provide a microporous polyolefin film having a high mechanical strength and a high film breaking resistance. SOLUTION: The microporous polyolefin film is characterized in that it has a film thickness of 2-60 μm, a piercing strength of 0.07-0.50 N/μm, a machine direction (MD) modulus/transverse direction (TD) modulus ratio (MD modulus/TD modulus) ratio of 3-20, a surface roughness (Ra) of the film of 0.3-0.6 μm, and a film thickness change under hot press conditions of a temperature of 70°C, a pressure of 2 MPa, and a time of 30 sec is larger by at least 0.5 μm than the surface roughness (Ra) of the film before the hot press. COPYRIGHT: (C)2009,JPO&INPIT |
