Rubber composition for use in tire treads
View Patent ↗A rubber composition in which from 80 to 150 parts by weight of carbon black having a nitrogen adsorption specific surface area of from 200 to 400 m 2 /g is compounded per 100 parts by weight of styrene-butadiene rubber including from 60% to 100% by weight of solution-polymerized styrene-butadiene rubber S-SBR1 and from 40% to 0% by weight of solution-polymerized styrene-butadiene rubber S-SBR2 to result in a total of 100% by weight, the styrene quantity of the S-SBR1 being from 30% to 38% by weight, the vinyl quantity of the S-SBR1 being from 60% to 80% by weight, the glass transition temperature of the S-SBR1 being from −20° C. to −5° C., the weight-average molecular weight of the S-SBR1 being from 1,000,000 to 1,800,000, the glass transition temperature of the S-SBR2 being not less than −30° C. and less than −20° C., and the weight-average molecular weight of the S-SBR2 being from 1,000,000 to 1,800,000.
1. A rubber composition for use in tire treads, comprising from 80 to 150 parts by weight of carbon black having a nitrogen adsorption specific surface area of from 200 to 400 m 2 /g being compounded per 100 parts by weight of styrene-butadiene rubber including from 60% to 100% by weight of solution-polymerized styrene-butadiene rubber S-SBR1 and from 40% to 0% by weight of solution-polymerized styrene-butadiene rubber S-SBR2 so as to result in a total of 100% by weight, a styrene quantity of the S-SBR1 being from 30% to 38% by weight, a vinyl quantity of the S-SBR1 being from 62% to 80% by weight, a glass transition temperature of the S-SBR1 being from −20° C. to −5° C., a weight-average molecular weight of the S-SBR1 being from 1,000,000 to 1,800,000, a glass transition temperature of the S-SBR2 being not less than −30° C. and less than −20° C., and a weight-average molecular weight of the S-SBR2 being from 1,000,000 to 1,800,000.
2. The rubber composition for use in tire treads according to claim 1 , wherein the content of S-SBR1 in 100% by weight of the styrene-butadiene rubber is from 70% to 100% by weight.
3. The rubber composition for use in tire treads according to claim 1 , wherein the styrene quantity of the S-SBR1 is from 32% to 37% by weight.
4. The rubber composition for use in tire treads according to claim 1 , wherein the vinyl quantity of the S-SBR1 is from 62% to 70% by weight.
5. The rubber composition for use in tire treads according to claim 1 , wherein the glass transition temperature of the S-SBR1 is from −18° C. to −7° C.
6. The rubber composition for use in tire treads according to claim 1 , wherein the weight-average molecular weight of the S-SBR1 is from 1,200,000 to 1,600,000.
7. The rubber composition for use in tire treads according to claim 1 , wherein the content of S-SBR2 in 100% by weight of the styrene-butadiene rubber is from 30% to 0% by weight.
8. The rubber composition for use in tire treads according to claim 1 , wherein the glass transition temperature of the S-SBR2 is not less than −28° C. and less than −22° C.
9. The rubber composition for use in tire treads according to claim 1 , wherein the weight-average molecular weight of the S-SBR2 being from 1,100,000 to 1,500,000.
10. The rubber composition for use in tire treads according to claim 1 , wherein from 10 to 50 parts by weight of aromatic modified terpene resin is compounded per 100 parts by weight of the styrene-butadiene rubber.
11. The rubber composition for use in tire treads according to claim 10 , wherein from 0.2 to 5 parts by weight of a cyclic polysulfide expressed by formula (I) below is compounded per 100 parts by weight of the styrene-butadiene rubber:
wherein R is a substituted or unsubstituted alkylene group having from 4 to 8 carbons, or a substituted or unsubstituted oxyalkylene group having from 4 to 8 carbons; x is a number averaging from 3 to 5; and n is an integer from 1 to 5.
12. The rubber composition for use in tire treads according to claim 1 , wherein from 20 to 45 parts by weight of aromatic modified terpene resin is compounded per 100 parts by weight of the styrene-butadiene rubber.
13. The rubber composition for use in tire treads according to claim 12 , wherein the aromatic modified terpene resin comprises a styrene modified terpene resin having a softening point of from 70° C. to 160° C.
14. The rubber composition for use in tire treads according to claim 1 , wherein from 0.2 to 5 parts by weight of a cyclic polysulfide expressed by formula (I) below is compounded per 100 parts by weight of the styrene-butadiene rubber:
wherein R is a substituted or unsubstituted alkylene group having from 4 to 8 carbons, or a substituted or unsubstituted oxyalkylene group having from 4 to 8 carbons; and x is a number averaging from 3 to 5; and n is an integer from 1 to 5.
15. The rubber composition for use in tire treads according to claim 1 , comprising from 90 to 140 parts by weight of the carbon black having a nitrogen adsorption specific surface area of from 250 to 390 m 2 /g.
16. The rubber composition for use in tire treads according to claim 1 , further comprising a filler selected from one or more of the group consisting of:
silica, clay, mica, talc, calcium carbonate, aluminum hydroxide, aluminum oxide, and titanium oxide.
17. A pneumatic tire, comprising the rubber composition for use in tire treads described in claim 1 .
18. A pneumatic tire, comprising the rubber composition for use in tire treads described in claim 10 .
19. A pneumatic tire, comprising the rubber composition for use in tire treads described in claim 14 .
20. A pneumatic tire, comprising the rubber composition for use in tire treads described in claim 11 .