Rubber composition for a tire tread and pneumatic tire using the same
View Patent ↗A rubber composition for a tire tread including a diene rubber component and silica and carbon black, and a pneumatic tire provided with a tread manufactured from this rubber composition, the diene rubber component including: (A) from 30 to 80 mass % of a hydroxy group-containing aromatic vinyl-conjugated diene copolymer including from 20 to 30 mass % of aromatic vinyl units and from 0.1 to 10 mass % of isoprene units, and having an amount of vinyl bonds in a conjugated diene part from 40 to 60 mol %; (B) from 10 to 50 mass % of a high-cis butadiene rubber having an amount of 90 mol % or more of cis-1,4 bonds; and (C) from 10 to 50 mass % of natural rubber; wherein a total amount of the silica and the carbon black is from 90 to 150 parts by mass per 100 parts by mass of the diene rubber component.
1. A rubber composition for a tire tread comprising a diene rubber component and silica and carbon black, the diene rubber component comprising:
(A) from 30 to 80 mass % of a hydroxy group-containing aromatic vinyl-conjugated diene copolymer comprising from 20 to 30 mass % of aromatic vinyl units and from 0.1 to 10 mass % of isoprene units, and having an amount of vinyl bonds in a conjugated diene part from 40 to 60 mol %;
(B) from 10 to 50 mass % of a high-cis butadiene rubber having an amount of 90 mol % or more of cis-1,4 bonds; and
(C) from 10 to 50 mass % of natural rubber;
wherein a total amount of silica and carbon black is from 90 to 150 parts by mass per 100 parts by mass of the diene rubber component, and
wherein the high-cis butadiene rubber (B) is obtained by blending a high molecular weight butadiene rubber having a weight-average molecular weight of from 5.0×10 5 to 1.0×10 6 and a low molecular weight butadiene rubber having a weight-average molecular weight of from 6.0×10 3 to 6.0×10 4 in a solvent; and an amount of the low molecular weight butadiene rubber included is from 20 to 40 mass %.
2. The rubber composition for a tire tread according to claim 1 , wherein, following vulcanization, the rubber composition for a tire tread has a glass transition temperature in a range from −60° C. to −40° C.
3. The rubber composition for a tire tread according to claim 1 , wherein following vulcanization, the rubber composition for a tire tread has a durometer hardness of from 55 to 68 at 20° C.
4. A pneumatic tire provided with a tread manufactured from the rubber composition for a tire tread according to claim 1 .
5. The pneumatic tire according to claim 4 , wherein the pneumatic tire is a winter use tire.
6. The rubber composition for a tire tread according to claim 1 , wherein the carbon black has an ability to adsorb an amount of dibutyl phthalate from 70 m 2 /g to 150 m 2 /g.
7. The rubber composition for a tire tread according to claim 6 , wherein the carbon black has an ability to adsorb an amount of dibutyl phthalate from 80 m 2 /g to 140 m 2 /g.
8. The rubber composition for a tire tread pneumatic tire according to claim 1 , wherein the silica comprises 70 to 100 parts by mass per 100 parts by mass of the diene rubber component.
9. The rubber composition for a tire tread according to claim 1 , wherein the high-cis butadiene rubber comprises an amount of 95 mol % or more of cis-1,4 bonds.
10. The rubber composition for a tire tread according to claim 1 , wherein the high-cis butadiene rubber (B) is obtained by blending a high molecular weight butadiene rubber having a weight-average molecular weight of from 5.5×10 5 to 9.0×10 5 and a low molecular weight butadiene rubber having a weight-average molecular weight of from 6.0×10 3 to 6.0×10 4 in a solvent; and an amount of the low molecular weight butadiene rubber included is from 20 to 40 mass %.
11. The rubber composition for a tire tread according to claim 1 , wherein the high-cis butadiene rubber (B) is obtained by blending a high molecular weight butadiene rubber having a weight-average molecular weight of from 5.0×10 5 to 1.0×10 6 and a low molecular weight butadiene rubber having a weight-average molecular weight of from 1.0×10 4 to 5.0×10 4 in a solvent; and an amount of the low molecular weight butadiene rubber included is from 20 to 40 mass %.
12. The rubber composition for a tire tread according to claim 1 , wherein the high-cis butadiene rubber (B) is obtained by blending a high molecular weight butadiene rubber having a weight-average molecular weight of from 5.0×10 5 to 1.0×10 6 and a low molecular weight butadiene rubber having a weight-average molecular weight of from 6.0×10 3 to 6.0×10 4 in a solvent; and an amount of the low molecular weight butadiene rubber included is from 25 to 35 mass %.
13. The rubber composition for a tire tread according to claim 1 , wherein the silica comprises a wet silica having hydrous silicic acid as a main component.
14. The rubber composition for a tire tread according to claim 1 , wherein a nitrogen specific surface area of the silica comprises from 100 m 2 /g to 200 m 2 /g.
15. The rubber composition for a tire tread according to claim 14 , wherein the nitrogen specific surface area of the silica comprises from 110 m 2 /g to 180 m 2 /g.
16. The rubber composition for a tire tread according to claim 1 , wherein the carbon black comprises furnace black.
17. The rubber composition for a tire tread according to claim 1 , wherein a nitrogen specific surface area of the carbon black comprises from 70 m 2 /g to 150 m 2 /g.
18. The rubber composition for a tire tread according to claim 17 , wherein the nitrogen specific surface area of the carbon black comprises from 80 m 2 /g to 140 m 2 /g.
19. The rubber composition for a tire tread according to claim 1 , wherein the total amount of silica and carbon black is from 100 to 140 parts by mass per 100 parts by mass of the diene rubber component.