Rubber composition and heavy-duty tire using same

Abstract

The present invention discloses a rubber composition, wherein, relative to 100 parts by mass of a rubber component containing 50% or more of an isoprene-based rubber, the combined amount of carbon black and silica is 40-65 parts by mass, and the combined amount of silica and a resin is 30 parts by mass or less; the ratio of silica to the resin is 1:9 to 9:1; and formulae (1) and (2) are satisfied. Formula (1): 2.0°C ≤ T1-T0 ≤ 7.0°C (where T1 denotes the temperature at the peak of the tan δ curve for the rubber composition; and T0 denotes the temperature at the peak of the tan δ curve for a rubber composition without the resin). Formula (2): 0.55 ≤ P1-P100 ≤ 0.90 (wherein P1 denotes the peak tan δ value in the tan δ curve for the rubber composition; and P100 denotes the tan δ value of the rubber composition at 100°C).

Claims

1. A rubber composition containing an isoprene-based rubber component, carbon black, silica, and resin, wherein the isoprene-based rubber accounts for 50 parts by mass or more of 100 parts by mass of the rubber component, the total amount of carbon black and silica is 40 to 65 parts by mass per 100 parts by mass of the rubber component, the total amount of silica and resin is 30 parts by mass or less per 100 parts by mass of the rubber component, the ratio of silica to resin is 1:9 to 9:1 as the former:latter (mass ratio), and satisfies the following formulas (1) and (2). 2.0℃≦T １ -T ０ ≤7.0℃ (1) 0.55 ≤P １ -P １００ ≦0.90 (2) In formula (1), T １ This is the peak temperature of the tanδ curve of the rubber composition, and T ０ P is the peak temperature of the tanδ curve of the rubber composition when the resin is removed from the rubber composition. In formula (2), P １ This is the tanδ value at the peak of the tanδ curve of the rubber composition, and P １００ This is the tanδ value of the rubber composition at 100°C.

2. The rubber composition according to claim 1, characterized in that the glass transition temperature of the rubber component is -55°C or lower.

3. The rubber composition according to claim 1, which satisfies the following formula (3). (P １００ −P ０ ) × MW ≤ 25 (3) In formula (3), P １００ is the tan δ value of the rubber composition at 100°C, and P ０ is the tan δ value of the rubber composition at 100°C when the resin is removed from the rubber composition, and MW is the weight average molecular weight of the resin.

4. The rubber composition according to claim 1, characterized in that 0.1 to 10 parts by mass of a processing aid is further added to 100 parts by mass of the rubber component.

5. The rubber composition according to claim 1, characterized in that the resin is selected from terpene resins, rosin resins, petroleum resins, phenolic resins, xylene resins, styrene resins, dicyclopentadiene resins, hydrogenated styrene resins, and hydrogenated dicyclopentadiene resins.

6. The rubber composition according to claim 1, characterized in that the weight-average molecular weight (MW) of the resin is 300 to 2000.

7. A heavy-duty tire comprising the rubber composition described in claim 1 in the tire tread.

8. A heavy-duty tire according to claim 5, having a plurality of circumferential main grooves extending in the circumferential direction of the tire, and at least three rows of land sections partitioned by the circumferential main grooves, wherein the tire tread width is W and the width of the outermost row of land sections in the tire width direction is Wsh, and the following formula (4) is satisfied: 0.15 ≤ Wsh / W ≤ 0.27 (4) 9. The heavy-duty tire according to claim 5, characterized in that when the tread gauge at the tread center portion located in the center of the tire width direction is Gcc, the following formula (5) is satisfied: 12.0 mm ≤ Gcc ≤ 30.0 mm (5)

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