Electrically neutral nonpermselective porous membrane

Claim 1

An electrically neutral nonpermselective porous membrane suitable for use in an electrodeposition system which exhibits a comparative acid removal number of from about 250 to 400 milli equivalents which comprises a woven fabric substrate having coated thereon a mixture of a binder material and a non-ion exchangeable inert porous filler material in a filler to binder weight ratio of 0.8:1 to 5:1, wherein the binder comprises at least one material selected from the group consisting of polyvinylchloride, polyvinylidene chloride, polyvinylidene fluoride, polyvinyl acetate, cellulose acetate, polyacrylonitrile, acrylic polymers and stryene polymers; and the filler comprises at least one material selected from the group consisting of macroporous crosslinked styrene based polymers, gel type crosslinked styrene based polymers, wood, starch, sugar, flour, natural gum, gelatin, and cellulose, with the porosity of said filler material forming a plurality of random paths which pass through the thickness of the membrane, with said membrane being capable of transmitting negatively and positively charged ions between the electrodes in an electrodeposition painting operation and at the same time capable of preventing backflow of the electrolytes between the electrode chambers.