| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an improved multi-layered microporous films used as a battery separator membrane, which shows an increase in mixed penetration strength, while maintaining low shrinkage values and Gurley numbers in a desirable range. <P>SOLUTION: A multi-layer microporous battery separator membrane comprises: a high molecular weight polypropylene layer having a melt flow index (MFI) of 1.2 or less measured in the layer; a polyethylene layer; and a high molecular weight polypropylene layer having a melt flow index of 1.2 or less measured in the layer. The multi-layer microporous battery separator membrane is formed by a dry stretch process, and has a thickness of 25 μ or less and a porosity of 37% or less while maintaining a Gurley number of 13-25 seconds. <P>COPYRIGHT: (C)2013,JPO&INPIT |
