| abstract |
Provided is a nonaqueous secondary battery separator having a porous substrate, and, formed on at least one surface of the porous substrate, an adhesive porous layer which contains a polyvinylidene fluoride resin (A) and a polyvinylidene fluoride resin (B) described below.n(1) The polyvinylidene fluoride resin (A) is selected from a group consisting of vinylidene fluoride homopolymers with a weight-average molecular weight of 600,000-2,500,000, and vinylidene fluoride copolymers with a weight-average molecular weight of 600,000-2,500,000 which contain vinylidene fluoride-derived structural units and hexafluoropropylene-derived structural units, the content of hexafluoropropylene-derived structural units accounting for 1.5 mol% or less of all total structural units.n(2) The polyvinylidene fluoride resin (B) contains vinylidene fluoride-derived structural units and hexafluoropropylene-derived structural units, wherein the content of hexafluoropropylene-derived structural units accounts for greater than 1.5 mol% of all structural units. |