Aromatic polyamide porous film, method for producing aromatic polyamide porous film, and secondary battery

摘要

The problem addressed by this invention is to provide an aromatic polyamide porous film excellent in the capability of being thinned and capable of easily exhibiting stable porosity properties even if it is used for a long period of time at high temperature. This invention can be achieved by an aromatic polyamide porous film that contains an aromatic polyamide as a main component and is such that when an atomic force microscope is used to measure a range of S µm 2 at least on one surface, the sectional area S(10) µm 2 obtained at a depth of 10 nm from the surface and the sectional area S(20) µm 2 obtained at a depth of 20 nm from the surface satisfy the following formulae simultaneously. 0.01 ‰ S 10 / S ‰ 0.3 5 ‰ S ( 20 ) / S 10 ‰ 20