# US 2021/0198397 A1 · Method for producing pellets, pellets and ion exchange film > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0198397 A1 - Document ID: US20210198397A1 - Status: Published application - Kind: A1 - Application number: 17/194,998 - Filed: 2021-03-08 - Published: 2021-07-01 - Earliest claimed: 2018-09-14 - Assignees: AGC Inc. - Applicants: AGC Inc. - Inventors: Hiromitsu KUSANO - Web page: https://patentgrep.com/patent/US20210198397A1 ## CPC - C08F 214/182: {Monomers containing fluorine not covered by the groups C08F214/20 - C08F214/28} - B29B 9/06: in the form of filamentary material, e.g. combined with extrusion - B29B 9/12: characterised by structure or composition - B29B 9/16: Auxiliary treatment of granules - B29C 48/86: at the nozzle zone - C08F 8/12: Hydrolysis - C08F 8/44: Preparation of metal salts or ammonium salts - C08F 214/262: {with fluorinated vinyl ethers} - C08F 216/1408: {Monomers containing halogen} - C08F 216/1475: {Monomers containing sulfur and oxygen} - C08J 3/12: Powdering or granulating - C08J 5/2237: {containing fluorine} - C25B 13/08: based on organic materials - B29K 2027/16: {PVDF, i.e. polyvinylidene fluoride} - B29K 2027/18: PTFE, i.e. polytetrafluoroethylene {, e.g. ePTFE, i.e. expanded polytetrafluoroethylene} - C08J 2327/12: containing fluorine atoms - C08J 2327/18: Homopolymers or copolymers of tetrafluoroethylene - C08J 2333/16: Homopolymers or copolymers of esters containing halogen atoms - Y02E 60/50: Fuel cells - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - 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) - C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract To provide a method for producing pellets from which an ion exchange membrane excellent in stability of the electrolysis voltage can be formed, pellets, and an ion exchange membrane. The method for producing pellets of the present invention is a method for producing pellets, which comprises extruding a melt containing a fluorinated polymer having groups convertible to ion exchange groups from a die of a melt-extruder to obtain a strand containing the fluorinated polymer, and cutting the strand to obtain pellets containing the fluorinated polymer, wherein the temperature of the die when the melt containing the fluorinated polymer is extruded from the die is less than 200° C., and when the groups convertible to ion exchange groups of the fluorinated polymer are converted to ion exchange groups, the ion exchange capacity of the resulting fluorinated polymer is at least 1.1 milliequivalent/g dry resin. ## Claims ### Claim 1 A method for producing pellets, which comprises extruding a melt containing a fluorinated polymer having groups convertible to ion exchange groups from a die of a melt-extruder to obtain a strand containing the fluorinated polymer, and cutting the strand to obtain pellets containing the fluorinated polymer, wherein the temperature of the die when the melt containing the fluorinated polymer is extruded from the die is less than 200° C., and when the groups convertible to ion exchange groups of the fluorinated polymer are converted to ion exchange groups, the ion exchange capacity of the resulting fluorinated polymer is at least 1.1 milliequivalent/g dry resin. ### Claim 2 (depends on 1) The method for producing pellets according to claim 1, wherein the strand is cut to obtain pellets containing the fluorinated polymer having a light transmittance of from 30 to 60%. ### Claim 3 (depends on 1) The method for producing pellets according to claim 1, wherein when the groups convertible to ion exchange groups of the fluorinated polymer are converted to ion exchange groups, the ion exchange capacity of the resulting fluorinated polymer is at most 2.00 milliequivalent/g dry resin. ### Claim 4 (depends on 1) The method for producing pellets according to claim 1, wherein the groups convertible to ion exchange groups are groups convertible to carboxylic acid functional groups or groups convertible to sulfonic acid functional groups. ### Claim 5 (depends on 1) The method for producing pellets according to claim 1, wherein the fluorinated polymer having groups convertible to ion exchange groups is a copolymer of a fluorinated olefin and a monomer represented by the following formula (1): CF2═CF—(O)p—(CF2)q—(CF2CFX)r—(O)s—(CF2)t—(CF2CFX′)u-A1 Formula (1): wherein X and X′ are each independently a fluorine atom or a trifluoromethyl group, Al is a group convertible to a carboxylic acid functional group, p is an integer of 0 or 1, q is an integer of from 0 to 12, r is an integer of from 0 to 3, s is an integer of from 0 or 1, t is an integer of from 0 to 12, and u is an integer of from 0 to 3, provided that 1≤p+s, and 1≤r+u. ### Claim 6 (depends on 1) The method for producing pellets according to claim 1, wherein the fluorinated polymer having groups convertible to ion exchange groups is a copolymer of a fluorinated olefin and a monomer represented by the following formula (2): CF2═CF-L-(A)n Formula (2): wherein L is a n+1 valent perfluorinated hydrocarbon group which may contain an oxygen atom, n is 1 or 2, and A is a group convertible to a sulfonic acid functional group. ### Claim 7 (depends on 6) The method for producing pellets according to claim 6, wherein the monomer represented by the formula (2) is a compound represented by the formula (2-1), a compound represented by the formula (2-2) or a compound represented by the formula (2-3): wherein Rf1 is a perfluoroalkylene group which may contain an oxygen atom between carbon atoms, Rf2 is a single bond or a perfluoroalkylene group which may contain an oxygen atom between carbon atoms, and A is as defined for the formula (2). ### Claim 8 (depends on 1) The method for producing pellets according to claim 1 wherein the pellets are used for producing an ion-exchange membrane. ### Claim 9 Pellets containing a fluorinated polymer having groups convertible to ion exchange groups, wherein when the groups convertible to ion exchange groups of the fluorinated polymer are converted to ion exchange groups, the ion exchange capacity of the resulting fluorinated polymer is at least 1.1 milliequivalent/g dry resin, and the pellets have a light transmittance of from 30 to 60%. ### Claim 10 (depends on 9) The pellets according to claim 9, wherein the groups convertible to ion exchange groups are groups convertible to carboxylic acid functional groups or groups convertible to sulfonic acid functional groups. ### Claim 11 (depends on 9) The pellets according to claim 9, to be used for producing an ion exchange membrane. ### Claim 12 (depends on 9) An ion exchange membrane formed by using the pellets as defined in claim 9. ### Claim 13 (depends on 12) The ion exchange membrane according to claim 12, which has a membrane thickness of from 30 to 180 μm. ### Claim 14 (depends on 12) The ion exchange membrane according to claim 12, to be used for electrolysis of aqueous alkali chloride.