PROCESS FOR PRODUCTION OF COMPOSITE POROUS FILM

摘要

A process for producing a composite porous film is provided to produce a non-aqueous secondary battery separator with good handling properties at low cost, therefore the ion permeability, adhesion with electrodes and electrolyte solution retention can be strictly controlled. A process for production of a composite porous film composed of an organic polymer compound surrounding a porous support comprises: coating both sides of a porous support(1) with a solution (dope) of an organic polymer compound and a water-soluble organic solvent using a coating apparatus; subsequently subjecting it to an air gap step and conveying the coated porous support into a coagulating bath(4) containing a coagulating solution consisting of water or a mixture of water with the same solvent as the organic solvent; immersing the porous support in the coagulating bath so that the coated film on both surfaces of the coated porous support contacts directly with the coagulating bath for coagulation, and then washing and drying it.