REACTIVE-POLYMER-CARRYING POROUS FILM AND PROCESS FOR PRODUCING THE SAME

摘要

A reactive-polymer-carrying porous film that enables production of a battery having satisfactory adhesion between electrode and separator, having low internal resistance and excelling in high rate performance, and that after battery production, itself is free from fusion or film breakage in high-temperature environment and functions as a separator of low thermal shrinkage; and a process for producing a battery with the use of the same. There is provided a reactive-polymer-carrying porous film for battery separator, characterized in that a porous film, as a base material, exhibiting a temperature of = 200°C, the temperature being one, when using a penetration probe type thermomechanical analyzer, a probe of 1 mm diameter under a load of 70 g is put on the porous film and while heating the porous film from room temperature at a temperature raising rate of 2°C/min, the thickness thereof is measured, exhibited at a reduction of the thickness of the porous film to 1/2 of that at the putting of the probe carries a reactive polymer, the reactive polymer obtained by copolymerizing a crosslinkable monomer having at least one reactive group selected from among 3-oxetanyl and epoxy in each molecule with a crosslinkable monomer having a reactive group capable of reaction with isocyanate to thereby obtain a crosslinkable polymer and reacting the crosslinkable polymer with a polyisocyanate so as to effect partial crosslinking.