abstract |
Polyolefin microporous membrane with a length of 1000 m or more, which is suitable for forming a porous layer with less uneven thickness, and the fluctuation of the F25 value in the longitudinal direction is 1 MPa or less (here, the F25 value means that the test piece was stretched by 25% using a tensile tester. It represents the value obtained by dividing the load value at the time of the test piece by the cross-sectional area) |