# US 12,009,555 B2 · Radical-curable seal member for fuel cell > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,009,555 B2 - Document ID: US12009555B2 - Status: Granted - Kind: B2 - Application number: 17/344,918 - Filed: 2021-06-10 - Published: 2021-10-07 - Granted: 2024-06-11 - Earliest claimed: 2019-08-28 - Assignees: Sumitomo Riko Company Limited - Applicants: Sumitomo Riko Company Limited - Inventors: Shota Taniguchi; Yasunori Nimura; Kenji Yamamoto - Web page: https://patentgrep.com/patent/US12009555B2 ## CPC - C08F 290/046: {Polymers of unsaturated carboxylic acids or derivatives thereof} - H01M 8/0284: Organic resins; Organic polymers - C08F 265/06: Polymerisation of acrylate or methacrylate esters on to polymers thereof - C08K 3/36: Silica - C08K 5/103: with polyalcohols - C08K 9/06: with silicon-containing compounds - C09K 3/10: {Materials in mouldable or extrudable form} for sealing or packing joints or covers (filling pastes C09D5/34) - H01M 8/0276: Sealing means characterised by their form (H01M8/0273 takes precedence) - H01M 8/0282: Inorganic material - H01M 8/1004: characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence) - H01M 2008/1095: {Fuel cells with polymeric electrolytes} - Y02E 60/50: Fuel cells - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A radical-curable seal member for fuel cell 4 having a glass transition temperature of −40° C. or lower made from a crosslinked product of a radical-curable composition containing (A) (Meth)acrylic polymer having a (meth)acryloyl group at a molecular chain end, (B) Monofunctional (meth)acrylic monomer, (C) Polyfunctional (meth)acrylic monomer and (D) Radical polymerization initiator, wherein the radical-curable composition contains 20 to 90 weight parts of component (B), 1 to 10 weight parts of component (C), 0.01 to 10 weight parts of component (D) with respect to 100 weight parts of component (A), a weight ratio [(B)/(C)] of the component (B) with respect to the component (C) being 4 to 24, and a content [(C)/{(A)+(B)+(C)}] of the component (C) with respect to a total of 100 wt % of the component (A), the component (B), and the component (C) being 1 to 7 wt %. ## Claims ### Claim 1 A radical-curable seal member for fuel cell, comprising a crosslinked product of a radical-curable composition and having a glass transition temperature (Tg) of −40° C. or lower, wherein the radical-curable composition comprises: (A) (Meth)acrylic polymer having a (meth)acryloyl group at a molecular chain end, (B) Monofunctional (meth)acrylic monomer, (C) Polyfunctional (meth)acrylic monomer, and (D) Radical polymerization initiator, wherein the radical-curable composition contains 20 to 90 weight parts of the component (B), 1 to 10 weight parts of the component (C), and 0.01 to 10 weight parts of the component (D) with respect to 100 weight parts of the component (A), and a weight ratio [(B)/(C)] of the component (B) with respect to the component (C) is 4 to 24, and a content [(C)/{(A)+(B)+(C)}] of the component (C) with respect to a total of 100 wt % of the component (A), the component (B), and the component (C) is 1 to 7 wt %. ### Claim 2 (depends on 1) The radical-curable seal member for fuel cell according to claim 1, wherein a glass transition temperature (Tg) of the component (B) is −40° C. or lower. ### Claim 3 (depends on 1) The radical-curable seal member for fuel cell according to claim 1, wherein the component (B) is at least one selected from a group consisting of 2-ethylhexyl acrylate, n-butyl acrylate, nonyl acrylate, isodecyl acrylate, and n-octyl acrylate. ### Claim 4 (depends on 1) The radical-curable seal member for fuel cell according to claim 1, wherein a number average molecular weight (Mn) of the component (A) is 5,000 to 100,000. ### Claim 5 (depends on 1) The radical-curable seal member for fuel cell according to claim 1, wherein the component (A) is a copolymer composed of an acrylic acid ester monomer having an ester group having 2 to 14 carbon atoms, or a copolymer composed of a methacrylic acid ester monomer having an ester group having 8 to 14 carbon atoms. ### Claim 6 (depends on 1) The radical-curable seal member for fuel cell according to claim 1, wherein the component (A) is a copolymer composed of n-butyl acrylate and 2-ethylhexyl acrylate. ### Claim 7 (depends on 6) The radical-curable seal member for fuel cell according to claim 6, wherein a copolymerization ratio of the copolymer (n-butyl acrylate:2-ethylhexyl acrylate) is 40 to 60:60 to 40. ### Claim 8 (depends on 1) The radical-curable seal member for fuel cell according to claim 1, wherein the component (C) is at least one selected from a group consisting of 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate and pentaerythritol acrylate-based compounds. ### Claim 9 (depends on 1) The radical-curable seal member for fuel cell according to claim 1, further comprising silica. ### Claim 10 (depends on 9) The radical-curable seal member for fuel cell according to claim 9, wherein the silica is at least one selected from a group consisting of dimethylsilylated silica, trimethylsilylated silica, octylsilylated silica, and methacrylsilylated silica. ### Claim 11 (depends on 1) The radical-curable seal member for fuel cell according to claim 1, wherein the radical-curable composition is an ultraviolet curable composition. ### Claim 12 (depends on 1) The radical-curable seal member for fuel cell according to claim 1, wherein the radical-curable seal member for fuel cell is a film-like seal member. ### Claim 13 (depends on 12) The radical-curable seal member for fuel cell according to claim 12, wherein a thickness of the film-like seal member is 50 to 1,000 μm.