VARNISH, POROUS POLYIMIDE FILM PRODUCED USING SAID VARNISH, AND METHOD FOR PRODUCING SAID FILM

摘要

The purpose of the present invention is to provide a production method which enables the production of a homogeneous and highly dense porous polyimide film and a separator equipped with the porous polyimide film by removing resin microparticles from a polyimide film containing the resin microparticles by thermal decomposition. A method for producing a porous polyimide film according to the present invention comprises: a baking step of baking an unbaked composite film comprising a polyamic acid or polyimide, resin microparticles and a condensing agent at a temperature that is lower than the decomposition temperature of the resin microparticles to produce a polyimide-(resin microparticle) composite film; and a microparticle removal step of removing the resin microparticles from the polyimide-(resin microparticle) composite film.