# US 10,501,608 B2 · Rubber composition for tire tread > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,501,608 B2 - Document ID: US10501608B2 - Status: Granted - Kind: B2 - Application number: 15/561,971 - Filed: 2015-03-26 - Published: 2018-05-10 - Granted: 2019-12-10 - Earliest claimed: 2015-03-26 - Assignees: The Yokohama Rubber Co., Ltd. - Applicants: The Yokohama Rubber Co., LTD. - Inventors: Masaki Sato - Web page: https://patentgrep.com/patent/US10501608B2 ## CPC - C08L 9/00: Compositions of homopolymers or copolymers of conjugated diene hydrocarbons - B60C 1/00: Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition - B60C 1/0016: {Compositions of the tread} - B60C 11/0008: {characterised by the tread rubber} - C08J 3/22: using masterbatch techniques - C08J 3/226: {using a polymer as a carrier} - C08J 9/0061: {characterized by the use of several polymeric components} - C08J 9/32: from compositions containing microballoons, e.g. syntactic foams - C08K 3/36: Silica - C08K 5/14: Peroxides - C08K 9/10: Encapsulated ingredients - C08L 7/00: Compositions of natural rubber - C08L 15/00: Compositions of rubber derivatives (C08L11/00, C08L13/00 take precedence) - C08L 83/04: Polysiloxanes - C08J 2201/024: Preparation or use of a blowing agent concentrate, i.e. masterbatch in a foamable composition - C08J 2201/026: Crosslinking before of after foaming - C08J 2203/22: Expandable microspheres, e.g. Expancel® - C08J 2307/00: Characterised by the use of natural rubber - C08J 2309/00: Characterised by the use of homopolymers or copolymers of conjugated diene hydrocarbons - C08J 2383/04: Polysiloxanes - C08J 2483/04: Polysiloxanes - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES - 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) - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) ## Abstract Provided is a rubber composition for tire treads containing a diene rubber, from 1 to 20 parts by weight of a silica containing millable silicone rubber compound, and from 0.2 to 20 parts by weight of thermally expandable microcapsules, per 100 parts by weight of the diene rubber. A rubber hardness of the millable silicone rubber compound is from 10 to 50. ## Claims ### Claim 1 A rubber composition for a tire tread, wherein the rubber composition comprises: a diene rubber comprising natural rubbers and/or butadiene rubbers, from 1 to 20 parts by weight of a millable silicone rubber compound and from 0.2 to 20 parts by weight of a thermally expandable microcapsule having a structure in which a thermally expandable substance in encapsulated in a shell material formed from a thermoplastic resin, per 100 parts by weight of the diene rubber, the millable silicone rubber compound containing silica, and a rubber hardness of the millable silicone rubber compound being from 10 to 50. ### Claim 2 (depends on 1) The rubber composition for a tire tread according to claim 1, wherein a weight ratio (X/Y) of a compounded amount (X) of the millable silicone rubber compound to a compounded amount (Y) of the thermally expandable microcapsule is from 20/80 to 90/10. ### Claim 3 (depends on 1) The rubber composition for a tire tread according to claim 1, wherein the composition further comprises a peroxide-based cross-linking agent. ### Claim 4 (depends on 1) The rubber composition for a tire tread according to claim 1, wherein the rubber hardness of the millable silicone rubber compound is from 5 to 40 lower than a rubber hardness of a base rubber excluding the millable silicone rubber compound and the thermally expandable microcapsule from the rubber composition. ### Claim 5 (depends on 1) A method of producing the rubber composition for a tire tread described in claim 1, the method comprising: preparing a master batch by mixing the millable silicone rubber compound and the thermally expandable microcapsule in advance, and mixing the master batch and the diene rubber. ### Claim 6 (depends on 5) The method of producing the rubber composition for a tire tread according to claim 5, wherein the master batch further contains a peroxide-based cross-linking agent. ### Claim 7 (depends on 1) A studless tire comprising a tread portion formed from the rubber composition for a tire tread described in claim 1. ### Claim 8 (depends on 2) The rubber composition for a tire tread according to claim 2, further comprising a peroxide-based cross-linking agent. ### Claim 9 (depends on 8) The rubber composition for a tire tread according to claim 8, wherein the rubber hardness of the millable silicone rubber compound is from 5 to 40 lower than a rubber hardness of a base rubber excluding the millable silicone rubber compound and the thermally expandable microcapsule from the rubber composition. ### Claim 10 (depends on 9) A method of producing the rubber composition for a tire tread described in claim 9, the method comprising: preparing a master batch by mixing the millable silicone rubber compound and the thermally expandable microcapsule in advance, and mixing the master batch and the diene rubber. ### Claim 11 (depends on 10) The method of producing the rubber composition for a tire tread according to claim 10, wherein the master batch further contains a peroxide-based cross-linking agent. ### Claim 12 (depends on 9) A studless tire comprising a tread portion formed from the rubber composition for a tire tread described in claim 9. ### Claim 13 (depends on 1) The rubber composition for a tire tread according to claim 1, wherein the rubber composition is a studless tire tread rubber composition.