VARNISH FOR POROUS POLYIMIDE FILM PRODUCTION AND METHOD FOR PRODUCING POROUS POLYIMIDE FILM USING SAME

摘要

Provided are a varnish for porous polyimide film production which provides unsintered composite films which are less likely to have an island-in-sea structure, and a method for producing a porous polyimide film using the same. The varnish for porous polyimide film production according to the present invention comprises a resin including polyamic acid and/or polyimide, fine particles, and a solvent, and has a fine particle content of not less than 65% by volume relative to the total of the resin and the fine particles and a viscosity at 25ºC of not less than 550 mPa·s. Preferably, the varnish for porous polyimide film production further comprises a dispersant. The method for producing a porous polyimide film according to the present invention comprises: an unsintered composite film formation step of forming an unsintered composite film using the varnish for porous polyimide film production; a sintering step of sintering the unsintered composite film, thereby forming a polyimide-fine particle composite film; and a fine particle removal step of removing the fine particles from the polyimide-fine particle composite film.