# US 4,396,727 A · Cation exchange membrane and process for producing the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,396,727 A - Document ID: US4396727A - Status: Granted - Kind: A - Application number: 06/318,979 - Filed: 1981-11-09 - Granted: 1983-08-02 - Earliest claimed: 1980-11-17 - Assignees: Japan Atomic Energy Research Institute; Chlorine Engineers Corp., Ltd. - Inventors: Isao Ishigaki; Jiro Okamoto; Hiroyuki Harada - Web page: https://patentgrep.com/patent/US4396727A ## CPC - C08J 5/225: {containing fluorine} - C08F 255/02: on to polymers of olefins having two or three carbon atoms - C08F 259/08: on to polymers containing fluorine - C08J 2327/12: containing fluorine atoms - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS ## Abstract A uniform cation exchange membrane having a certain fluorovinyl sulfonic acid monomer grafted onto a certain high-molecular substrate film which exhibits small electrical resistance and great physical strength is herein disclosed. ## Claims ### Claim 1 A cation exchange membrane having a fluorovinyl sulfonic acid monomer grafted onto a high-molecular substrate film having a monomer of the formula: ##STR4## (wherein X is hydrogen, fluorine or CH.sub.3, and Y is hydrogen or fluorine) as a monomer unit. ### Claim 2 (depends on 1) A cation exchange membrane according to claim 1 wherein the fluorovinyl sulfonic acid monomer has the formula: CF.sub.2 .dbd.CF--CF.sub.2).sub.n SO.sub.2 Z (wherein n is 0 or 2, and Z is fluorine, hydroxyl group, NH.sub.2, ONH.sub.4 or OM, M being an alkali metal). ### Claim 3 (depends on 1) A cation exchange membrane according to claim 1 wherein the fluorovinyl sulfonic acid monomer has the formula: R.sub.1 --CF.dbd.CF-SO.sub.2 Z (wherein R.sub.1 is fluorine or a perfluoroalkyl group having 1 to 5 carbon atoms). ### Claim 4 (depends on 1) A cation exchange membrane according to claim 1 wherein the fluorovinyl sulfonic acid monomer has the formula: ##STR5## (wherein R.sub.2 is fluorine or a perfluoroalkyl group having 1 to 5 carbon atoms). ### Claim 5 (depends on 1) A cation exchange membrane according to claim 1 wherein the fluorovinyl sulfonic acid monomer has the formula: ##STR6## (wherein R.sub.3 is fluorine or CH.sub.3 ; R.sub.4 is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms; and l is an integer of 1 to 3). ### Claim 6 (depends on 1) A cation exchange membrane according to claim 1 wherein the fluorovinyl sulfonic acid monomer has the formula: ##STR7## (wherein R.sub.5 is fluorine or CH.sub.3 ; R.sub.6 is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms; and k is an integer of 1 to 3). ### Claim 7 (depends on 1) A cation exchange membrane according to claim 1 wherein the high-molecular substrate film is supported by a reinforcing material. ### Claim 8 A process for producing a cation exchange membrane wherein a high-molecular substrate film having a monomer of the formula: CH.sub.2 .dbd.CXY (wherein X is hydrogen, fluorine or CH.sub.3 ; and Y is hydrogen or fluorine) as a monomer unit is exposed to ionizing radiation, and then the substrate film is brought into contact with a solution of a fluorovinyl sulfonic acid monomer so as to graft the fluorovinyl sulfonic acid monomer onto the substrate film. ### Claim 9 (depends on 8) A process according to claim 8 wherein the dose of ionizing radiation is from 0.5 to 50 Mrad. ### Claim 10 (depends on 8) A process according to claim 8 wherein the substrate film is exposed to the ionizing radiation in the presence of an inert gas. ### Claim 11 (depends on 8) A process according to claim 8 wherein the exposed substrate film is brought into contact with the solution of fluorovinyl sulfonic acid monomer in the presence of a solvent which is miscible with said monomer. ### Claim 12 A process for producing a cation exchange membrane wherein a high-molecular substrate film having a monomer of the formula: CH.sub.2 .dbd.CXY (wherein X is hydrogen, fluorine or CH.sub.3 ; and Y is hydrogen or fluorine) as a monomer unit is brought into contact with a solution of a fluorovinyl sulfonic acid monomer, and then the mixture is exposed to ionizing radiation to give a total dose of 0.5 to 20 Mrad so as to graft the fluorovinyl sulfonic acid monomer onto the substrate film. ### Claim 13 (depends on 1) A process according to claim 1 wherein the substrate film is exposed to the ionizing radiation in the presence of an inert gas. ### Claim 14 (depends on 13) A process according to the claim 13 wherein the substrate film is brought into contact with the solution of fluorovinyl sulfonic acid monomer in the presence of a solvent that is miscible with said monomer. ### Claim 15 A process for producing a cation exchange membrane wherein a high-molecular substrate film having a monomer of the formula: CH.sub.2 .dbd.CXY (wherein X is hydrogen, fluorine or CH.sub.3 ; Y is hydrogen or fluorine) as a monomer unit is exposed to ionizing radiation to give a total dose of 0.5 to 20 Mrad, the substrate film is then brought into contact with a solution of a fluorovinyl sulfonic acid monomer, and the substrate film is further exposed to ionizing radiation to give a total dose of 0.5 to 20 Mrad so as to graft the fluorovinyl sulfonic acid monomer onto the substrate film. ### Claim 16 (depends on 15) A process according to claim 15 wherein the substrate film given the first dose of ionizing radiation is brought into contact with the solution of fluorovinyl sulfonic acid monomer in the presence of a solvent that is miscible with said monomer. ### Claim 17 (depends on 15) A process according to claim 15 wherein the substrate film is exposed to ionizing radiation in the presence of an inert gas. ### Claim 18 (depends on 1) A cation exchange membrane according to claim 1 of a polymer having repeating units ##STR8## and wherein said fluorovinyl sulfonic acid monomer is uniformly grafted thereto throughout said polymer.