| abstract |
A heat-resistant film comprising at least any one of a polybenzazole, aramid, and polyamide-imide, which is produced by sandwiching a polymer solution between at least two supports, forming the solution into a thin film by means of rolls, a slit, or a press, introducing the film to a coagulating bath, and removing the supports in the coagulating bath to coagulate the film; and a composite ion-exchange membrane comprising a composite layer comprising the film impregnated with an ion-exchange resin and, formed on each side of the composite layer, a surface layer which comprises an ion-exchange resin and includes no porous film. The heat-resistant film is excellent in all of heat resistance, mechanical strength, surface smoothness, and interlaminar peeling resistance and, in particular, has micropores. The composite ion-exchange membrane, which employs this heat-resistant film, has excellent ion conductivity. |