| abstract |
(57) Abstract: A porous film which has high ion permeability and can easily hold a non-aqueous electrolyte, particularly a polymer electrolyte containing a polymer electrolyte, and a method for producing the same. A separator for a non-aqueous electrolyte battery comprising a porous film, and a non-aqueous electrolyte battery using the separator. An ultrahigh molecular weight polyolefin resin having a weight average molecular weight of 5 × 10 5 or more and a particle diameter of 0.001 to 10 μm are provided. m, and having a surface pore size of 0.01 to 1 μm. m, a porous film having a cut surface pore diameter in the thickness direction of 0.1 to 10 μm and a ratio of surface pore diameter / cut surface hole diameter in the thickness direction smaller than 0.2, and containing an ultrahigh molecular weight polyolefin resin, a solvent and particles. A step of melt-kneading the resin composition to be formed, a step of forming the obtained melt-kneaded product into a sheet, A step of performing rolling and stretching of the obtained sheet-like molded product, A method for producing the porous film, comprising a step of removing a solvent by a solvent removal treatment. |