| abstract |
In the present invention, in the polyolefin microporous membrane having a porosity of 45% to 85%, the maximum pore size is 0.1 µm to 0.23 µm, the MD modulus is set to 400 MPa to 2000 MPa, and the MD modulus / TD modulus ratio is set to 1.5 to 9, Provided is a polyolefin microporous membrane which easily absorbs distortion when compressed and has excellent permeability and excellent insulation even after compression.n n n Polyolefin microporous membrane, nonaqueous electrolyte secondary battery, MD elastic modulus, TD elastic modulus |