| abstract |
It has been difficult to form a porous layer having a uniform thickness on a polyolefin microporous membrane having a wide width and a thin film by conventional coating techniques. The present invention provides a polyolefin microporous membrane suitable for forming a porous layer having less unevenness in thickness and a separator for a battery suitable for increasing the capacity of a battery. The width of the F25 value in the width direction is 1 MPa or less, the thickness is 3 占 퐉 or more, less than 7 占 퐉, and the width is 100 mm or more (here, the F25 value is a load when a test piece is stretched by 25% Value divided by the cross-sectional area of the specimen) |