| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve separator characteristics of a layered microporous film including a base material made of a nonwoven fabric. <P>SOLUTION: A layered microporous film including a surface layer containing a resin material and an inorganic particle on at least one surface of a base material made of a nonwoven fabric is adjusted so that the coefficient of thickness fluctuation of film thickness represented by a standard deviation is 2.5% or less. The adjustment is performed by subjecting the layered microporous film to pressure treatment from at least one surface of the surface layer. The pressure treatment is, for example, calendering treatment, and the layered microporous film can be obtained by setting a pressing force in the calendering treatment at 20 kgf/cm or more and 200 kgf/cm or less in linear pressure. <P>COPYRIGHT: (C)2012,JPO&INPIT |
