Tire rubber composition and tire

Abstract

The problem is solved by a tire rubber composition characterized by comprising a rubber component, a filler, and syndiotactic 1,2-polybutadiene, wherein: the rubber component includes cyclopentene and a copolymer with a norbornene-based compound represented by general formula (1) (in the formula, R1-R4 each independently represent a hydrogen atom, a C1-C20 hydrocarbon group, or a substituent containing a halogen atom, a silicon atom, an oxygen atom, or a nitrogen atom, R2 and R3 may be bonded to each other to form a ring, and m is an integer of 0–2.); and the syndiotactic 1,2-polybutadiene has a crystal content of 7–40 J / g and a number-average molecular weight of 3.0 × 104 or more.

Claims

1. The material comprises a rubber component, a filler, and syndiotactic 1,2-polybutadiene, wherein the rubber component is cyclopentene and the following general formula (1): [In the formula, R １ ~R ４ Each of these independently represents a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a substituent containing a halogen atom, a silicon atom, an oxygen atom, or a nitrogen atom, and R ２ and R ３ The compounds may bond to each other to form a ring, and m is an integer from 0 to 2. The compound contains a copolymer with a norbornene compound represented by [ ], and the syndiotactic 1,2-polybutadiene has a crystalline weight of 7 to 40 J / g and a number-average molecular weight of 3.0 × 10 ４ A rubber composition for tires, characterized by the above.

2. The tire rubber composition according to claim 1, wherein the content of the copolymer of cyclopentene and norbornene compound is 20 to 90 parts by mass per 100 parts by mass of the rubber component.

3. The rubber composition for tires according to claim 1, wherein the copolymer of cyclopentene and norbornene compound has a weight-average molecular weight (Mw) of 200,000 to 1,000,000.

4. The tire rubber composition according to claim 1, wherein the norbornene compound represented by the general formula (1) above is 2-norbornene and / or dicyclopentadiene.

5. The tire rubber composition according to claim 1, wherein the copolymer of cyclopentene and norbornene compound has a content of cyclopentene-derived structural units of 20 to 75% by mass.

6. The tire rubber composition according to claim 4, wherein the copolymer of cyclopentene and norbornene compound has a content of dicyclopentadiene-derived structural units of 10 to 60% by mass.

7. The tire rubber composition according to claim 1, wherein the rubber component further comprises isoprene backbone rubber and / or butadiene rubber.

8. The syndiotactic 1,2-polybutadiene has a number-average molecular weight of 5.0 × 10⁻⁶ ４ ~50.0 x 10 ４ The tire rubber composition according to claim 1.

9. The tire rubber composition according to claim 1, wherein the syndiotactic 1,2-polybutadiene has a degree of crystallinity of 15 to 60%.

10. The tire rubber composition according to claim 1, wherein the syndiotactic 1,2-polybutadiene has a melting point of 100 to 160°C.

11. The tire rubber composition according to claim 1, wherein the syndiotactic 1,2-polybutadiene has a 1,2-bond content of 80% by mass or more.

12. The tire rubber composition according to claim 1, wherein the syndiotactic 1,2-polybutadiene has a syndiotacticity of 60% or more in the 1,2-bonding.

13. The tire rubber composition according to claim 1, wherein the content of the syndiotactic 1,2-polybutadiene is 1 to 40 parts by mass per 100 parts by mass of the rubber component.

14. The tire rubber composition according to claim 1, comprising carbon black as the filler.

15. The tire rubber composition according to claim 14, wherein the carbon black content is 5 to 80 parts by mass per 100 parts by mass of the rubber component.

16. A tire characterized by comprising the tire rubber composition described in any one of claims 1 to 15.

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