| 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 (1) a polyvinylidene fluoride resin (A) and (2) a polyvinylidene fluoride resin (B) described below. (1) The polyvinylidene fluoride resin (A) is selected from a group consisting of vinylidene fluoride homopolymers, and vinylidene fluoride copolymers 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. (2) This polyvinylidene fluoride resin (B) is selected from vinylidene fluoride copolymers which contain vinylidene fluoride-derived structural units and hexafluoropropylene-derived structural units, with the content of hexafluoropropylene-derived structural units accounting for greater than 1.5 mol% of all structural units, and with a weight-average molecular weight of 300,000-2,500,000. |