| 摘要 |
PROBLEM TO BE SOLVED: To provide a porous film which, through the control of the crosslinked structure and the shrinkage force, has a high film strength at room temperature and even at a high temperature has excellent film rupture resistance, and provide its use. SOLUTION: The porous film, formed when a resin composition containing a polyolefin is crosslinked, has a needle piercing strength of≥2.5 [N/24μm] and a peak value of the shrinkage force per unit cross-sectional area in the temperature range above the shut-down temperature. When the peak value is regarded as the shrinkage force of the porous film, the relationship between the gel fraction measured in boiling xylene and the above shrinkage force is≥0.4 in terms of the value of the gel fraction [%]/the shrinkage force [N/cm<SP>2</SP>]. COPYRIGHT: (C)2008,JPO&INPIT |
