| 摘要 |
1320658 Ion exchange membrane RHONE POULENC SA 15 Feb 1972 [15 Feb 1971] 6938/72 Heading B1X [Also in Division B5] Screen-reinforced heterogeneous ion-exchange membranes are prepared by casting a solution or suspension of an ion-exchange resin and a binder material on to a flexible support film, evaporating the solvent, placing a composite so formed on either side of a reinforcing screen, hot-pressing the assembly and removing the support films. In a modification, two composites are hot-pressed together and the support films are removed to form a unitary layer, to each side of which a reinforcing screen is applied; a composite is then applied to the exposed face of each screen and the assembly is treated as above. The ion-exchange resin may be a styrene-divinylbenzene copolymer which has been chloromethylated and aminated, or which contains sulphonic acid groups. The binder may be a vinyl chloride polymer, e.g. a homopolymer, or a copolymer with a vinyl ester of a C 1 -C 6 acid or an alkyl maleate or fumarate; exemplified co-monomers are butyl maleate and vinyl acetate-maleic acid. The screen may be a woven polyvinyl chloride, copoly (vinylchloride-vinylidene chloride), polyethylene, polypropylene, polyamide, polyethylene terephthalate, glass or metal fabric, or a net or non-woven fabric. The support film is preferably polyethylene terephthalate, but may be polyvinyl alcohol, polyamide, polyimide or cellulose. |
