abstract |
In the present invention, a porous membrane for use in a secondary battery, which contains non-conductive particles and a water-soluble polymer, uses as a water-soluble polymer a copolymer that contains 15 to 50% by weight of an ethylene-unsaturated carboxylic acid monomer unit, 30 to 80% by weight of a (meth) acrylic acid ester monomer unit, and 0.5 to 10% by weight of a fluorine-containing (meth) acrylic acid ester monomer unit. |