# US 11,309,136 B2 · Electrolyte solution for electrolytic capacitor and electrolytic capacitor utilizing said electrolyte solution > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,309,136 B2 - Document ID: US11309136B2 - Status: Granted - Kind: B2 - Application number: 16/075,992 - Filed: 2017-02-08 - Published: 2021-06-24 - Granted: 2022-04-19 - Earliest claimed: 2016-02-08 - Assignees: Sanyo Chemical Industries, Ltd. - Applicants: Sanyo Chemical Industries, Ltd. - Inventors: Fumiyuki Tanabe; Takahiro Shiba; Yoshihiko Akazawa; Takao Mukai - Web page: https://patentgrep.com/patent/US11309136B2 ## CPC - H01G 9/035: Liquid electrolytes, e.g. impregnating materials (H01G11/54 takes precedence) - H01G 9/145: Liquid electrolytic capacitors (H01G11/00 takes precedence) - H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10) ## Abstract The purpose of the present invention is to provide an electrolyte solution for an electrolytic capacitor which has high withstand voltage. The electrolyte solution for an electrolytic capacitor that is used contains: an organic solvent; an acrylic polymer which has hydroxy group and/or carboxy group; and an electrolyte. A concentration of hydroxy groups included in the organic solvent is 10 mmol/g or less with respect to the weight of the organic solvent. ## Claims ### Claim 1 An electrolyte solution for an electrolytic capacitor comprising a solvent containing an organic solvent, an acrylic polymer having hydroxy group and/or carboxy group, and an electrolyte, wherein a concentration of hydroxy groups included in the organic solvent is 10 mmol/g or less with respect to the weight of the organic solvent, a glass transition temperature of the acrylic polymer having hydroxy group and/or carboxy group is −80° C. to 56° C., and the acrylic polymer is a polymer that includes a monomer having (meth)acryloyl group and hydroxy group as essential constituent monomers. ### Claim 2 (depends on 1) The electrolyte solution for an electrolytic capacitor according to claim 1, wherein the acrylic polymer further comprises a monomer having (meth)acryloyl group and carboxy group as essential constituent monomers. ### Claim 3 (depends on 2) The electrolyte solution for an electrolytic capacitor according to claim 2, wherein the monomer having (meth)acryloyl group and carboxy group is at least one monomer selected from the group consisting of an adduct obtained by adding an acid anhydride having 4 to 10 carbon atoms to the monomer having (meth)acryloyl group and hydroxy group, an adduct obtained by adding 1 to 5 mol of a lactone having 2 to 12 carbon atoms to (meth)acrylic acid, and (meth)acrylic acid. ### Claim 4 (depends on 2) The electrolyte solution for an electrolytic capacitor according to claim 2, wherein a proportion of the total number of moles of the monomer having (meth)acryloyl group and hydroxy group and the monomer having (meth)acryloyl group and carboxy group to the total number of moles of constituent monomers of the acrylic polymer is 0.5 to 100 mol %. ### Claim 5 (depends on 1) The electrolyte solution for an electrolytic capacitor according to claim 1, wherein the monomer having (meth)acryloyl group and hydroxy group is at least one monomer selected from the group consisting of a hydroxyalkyl (meth)acrylate having 4 to 12 carbon atoms, an adduct obtained by adding 1 to 5 mol of a lactone having 2 to 12 carbon atoms to the hydroxyalkyl (meth)acrylate having 4 to 12 carbon atoms, and an adduct obtained by adding alkylene oxide having 2 to 10 carbon atoms to the hydroxyalkyl (meth)acrylate having 4 to 12 carbon atoms. ### Claim 6 (depends on 1) The electrolyte solution for an electrolytic capacitor according to claim 1, wherein a weight proportion of the acrylic polymer to the total weight of the electrolyte solution for an electrolytic capacitor is 0.5 to 40 weight %. ### Claim 7 (depends on 1) The electrolyte solution for an electrolytic capacitor according to claim 1, wherein an absolute value of a difference between a solubility parameter of the acrylic polymer having hydroxy group and/or carboxy group and a solubility parameter of the solvent is 0.1 to 5.0. ### Claim 8 (depends on 1) The electrolyte solution for an electrolytic capacitor according to claim 1, wherein the organic solvent is a lactone solvent and/or a sulfone solvent. ### Claim 9 (depends on 1) The electrolyte solution for an electrolytic capacitor according to claim 1, wherein the organic solvent is γ-butyrolactone. ### Claim 10 (depends on 1) The electrolyte solution for an electrolytic capacitor according to claim 1, wherein the electrolyte solution for an electrolytic capacitor contains water and a weight proportion of water to the total weight of the electrolyte solution for an electrolytic capacitor is 0.01 to 5 weight %. ### Claim 11 (depends on 1) The electrolyte solution for an electrolytic capacitor according to claim 1, further comprising boric acid and/or a borate ester. ### Claim 12 (depends on 11) The electrolyte solution for an electrolytic capacitor according to claim 11, wherein a proportion of the total weight of the boric acid and the borate ester to the total weight of the electrolyte solution for an electrolytic capacitor is 0.1 to 10 weight %. ### Claim 13 (depends on 1) An electrolytic capacitor, comprising an anode, a cathode, and a separator disposed between the anode and the cathode, wherein the electrolyte solution according to claim 1 is impregnated into the separator.