POROUS MEMBRANE FOR SECONDARY BATTERY, SEPARATOR FOR SECONDARY BATTERY, AND SECONDARY BATTERY

In a porous membrane for a secondary battery including non-conductive particles and a water-soluble polymer, as the water-soluble polymer, a copolymer including 15% to 50% by weight of an ethylenically 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 is used.