US 11,787,923 B2
Rubber composition for tire and pneumatic tire
Hiroki Sugimoto, Hiratsuka (JP); Shuichi Nakano, Hiratsuka (JP); and Makoto Ashiura, Hiratsuka (JP)
Assigned to The Yokohama Rubber Co., LTD., Tokyo (JP)
Appl. No. 16/77,405
Filed by The Yokohama Rubber Co., LTD., Tokyo (JP)
PCT Filed Feb. 8, 2017, PCT No. PCT/JP2017/004523
§ 371(c)(1), (2) Date Aug. 10, 2018,
PCT Pub. No. WO2017/138553, PCT Pub. Date Aug. 17, 2017.
Claims priority of application No. 2016-025224 (JP), filed on Feb. 12, 2016.
Prior Publication US 2021/0171746 A1, Jun. 10, 2021
Int. Cl. C08L 9/06 (2006.01); B60C 1/00 (2006.01); C08L 23/22 (2006.01); C08L 25/00 (2006.01); C08L 83/04 (2006.01); C08K 3/36 (2006.01); C08K 5/40 (2006.01)
CPC C08L 9/06 (2013.01) [B60C 1/0016 (2013.01); C08L 23/22 (2013.01); C08L 25/00 (2013.01); C08L 83/04 (2013.01); C08K 3/36 (2013.01); C08K 5/40 (2013.01); C08K 2201/006 (2013.01)] 11 Claims
 
1. A rubber composition for a tire comprising diene rubber, silica, and a silane coupling agent, wherein
the diene rubber comprises not less than 10 mass % of a specific conjugated diene rubber represented by Formula (1), and comprising a polymer block A comprising a structural unit based on a monomer and comprising isoprene and a structural unit based on a monomer and comprising aromatic vinyl, a polymer block B comprising a structural unit based on a monomer and comprising 1,3-butadiene, and a polymer block C comprising a polyorganosiloxane;
the diene rubber comprises butadiene rubber having a linearity index value from 120 to 150;
a mass ratio of the structural unit based on a monomer and comprising isoprene to the structural unit based on a monomer and comprising aromatic vinyl, the structural unit based on a monomer and comprising isoprene/the structural unit based on a monomer and comprising aromatic vinyl, in the polymer block A is from 80/20 to 95/5, and a formula weight of the polymer block A is from 500 to 15,000;
a CTAB adsorption specific surface area of the silica is from 180 to 250 m2/g;
the silane coupling agent is a silane coupling agent represented by Formula (2);
the polyorganosiloxane is a polyorganosiloxane represented by Formula (3); and
a vinyl bond content in the specific conjugated diene rubber is from 20 to 35 mass %:
A-B-C  Formula (1)
where A represents the polymer block A, B represents the polymer block B, and C represents the polymer block C;
(CpH2p+1)t(CpH2p+1O)3−t—Si—CqH2q—S—C(O)—CrH2r+1  Formula (2)
where p represents an integer from 1 to 3, q represents an integer from 1 to 3, r represents an integer from 1 to 15, and t represents an integer from 0 to 2; and

OG Complex Work Unit Chemistry
where R1 to R8 are each an alkyl group having from 1 to 6 carbons or an aryl group having from 6 to 12 carbons, and are optionally identical to or different from one another; X1 and X4 are each any group selected from the group consisting of an alkyl group having from 1 to 6 carbons, an aryl group having from 6 to 12 carbons, an alkoxy group having from 1 to 5 carbons, and an epoxy group-containing group having from 4 to 12 carbons, and are optionally identical to or different from one another; X2 is an alkoxy group having from 1 to 5 carbons or an epoxy group-containing group having from 4 to 12 carbons, and when a plurality of the X2 are present, the plurality of X2 are optionally identical to or different from one another; X3 is a group containing from 2 to 20 repeating alkylene glycol units, and when a plurality of the X3 are present, the plurality of X3 are optionally identical to or different from one another; and m is an integer from 3 to 200, n is an integer from 0 to 200, and k is an integer from 0 to 200.