# US 11,077,711 B2 · Rubber composition and pneumatic tire > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,077,711 B2 - Document ID: US11077711B2 - Status: Granted - Kind: B2 - Application number: 15/571,257 - Filed: 2016-04-22 - Published: 2018-05-17 - Granted: 2021-08-03 - Earliest claimed: 2015-05-01 - Assignees: The Yokohama Rubber Co., Ltd.; National University Corporation Kyoto Institute of Technology - Applicants: The Yokohama Rubber Co., LTD.; National University Corporation Kyoto Institute Of Technology - Inventors: Wataru Sakai; Takuma Arikawa; Ryosuke Sakai; Yu Shinke; Yuko Sekine; Fumito Yatsuyanagi - Web page: https://patentgrep.com/patent/US11077711B2 ## CPC - B60C 1/0016: {Compositions of the tread} - B60C 1/00: Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition - C08K 3/04: Carbon - C08K 3/36: Silica - C08L 7/00: Compositions of natural rubber - C08L 9/06: Copolymers with styrene - C08L 91/00: Compositions of oils, fats or waxes; Compositions of derivatives thereof - B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) ## Abstract A rubber composition of the present technology is a rubber composition including a diene rubber and a filler; the diene rubber containing at least a styrene-butadiene copolymer; a radical generation index of the styrene-butadiene copolymer being not greater than 1.0 and being smaller than a value Y calculated by Equation (1): Y=−0.0186×(SV mass %+vinyl unit mol %)+1.5. ## Claims ### Claim 1 A rubber composition comprising a diene rubber and a filler; the diene rubber containing a styrene-butadiene copolymer and a natural rubber, wherein the content of the styrene-butadiene copolymer is not less than 40 mass % and less than 50 mass % of the total mass of the diene rubber; a radical generation index of the styrene-butadiene copolymer being not greater than 1.0 and being smaller than a value Y calculated from an equation:Y=−0.0186×(SV mass %+vinyl unit mol %)+1.5 where the radical generation index is an index representation of a radical concentration using the radical concentration of a copolymer having a molar ratio of styrene units/1,2 vinyl units/1,4 trans units/1,4 cis units of 13/14/15/58 as a 1.0 reference value; and “SV mass %” in the equation is a mass % of a partial structure where a styrene single chain having one styrene unit and a vinyl single chain having one vinyl unit are directly linked relative to an amount of bonded styrene of the styrene-butadiene copolymer, and “vinyl unit mol %” in the equation is a mol % of vinyl units when a total of styrene units, 1,2 vinyl units, 1,4 trans units, and 1,4 cis units in the styrene-butadiene copolymer is defined as 100 mol %, and wherein the styrene single chain content having one styrene unit is not greater than 30 mass % of the amount of bonded styrene in the styrene-butadiene copolymer. ### Claim 2 (depends on 1) The rubber composition according to claim 1, wherein the styrene-butadiene copolymer has an amount of bonded styrene of not greater than 25 mol % and a vinyl unit content of not less than 30 mol %. ### Claim 3 (depends on 2) The rubber composition according to claim 2, wherein a partial structure content in which a styrene single chain having one styrene unit and a vinyl single chain having one vinyl unit are directly linked is not greater than 10 mass % of the amount of bonded styrene in the styrene-butadiene copolymer. ### Claim 4 (depends on 3) The rubber composition according to claim 3, wherein the filler is silica and/or carbon black. ### Claim 5 (depends on 2) The rubber composition according to claim 2, wherein the filler is silica and/or carbon black. ### Claim 6 (depends on 1) The rubber composition according to claim 1, wherein a partial structure content in which a styrene single chain having one styrene unit and a vinyl single chain having one vinyl unit are directly linked is not greater than 10 mass % of the amount of bonded styrene in the styrene-butadiene copolymer. ### Claim 7 (depends on 6) The rubber composition according to claim 6, wherein the filler is silica and/or carbon black. ### Claim 8 (depends on 1) The rubber composition according to claim 1, wherein the filler is silica and/or carbon black. ### Claim 9 (depends on 1) The rubber composition according to claim 1, wherein the content of the styrene-butadiene copolymer is less than 45 mass % of the total mass of the diene rubber. ### Claim 10 (depends on 1) The rubber composition according to claim 1, wherein the content of the natural rubber is greater than the content of the styrene-butadiene copolymer in the total mass of the diene rubber. ### Claim 11 (depends on 1) The rubber composition according to claim 1, wherein the content of the styrene-butadiene copolymer is not less than 47 mass % and less than 50 mass % of the total mass of the diene rubber. ### Claim 12 (depends on 1) A pneumatic tire comprising the rubber composition described in claim 1. ### Claim 13 (depends on 2) A pneumatic tire comprising the rubber composition described in claim 2. ### Claim 14 (depends on 3) A pneumatic tire comprising the rubber composition described in claim 3. ### Claim 15 (depends on 4) A pneumatic tire comprising the rubber composition described in claim 4. ### Claim 16 (depends on 5) A pneumatic tire comprising the rubber composition described in claim 5. ### Claim 17 (depends on 6) A pneumatic tire comprising the rubber composition described in claim 6. ### Claim 18 (depends on 7) A pneumatic tire comprising the rubber composition described in claim 7. ### Claim 19 (depends on 8) A pneumatic tire comprising the rubber composition described in claim 8.