Rubber composition and pneumatic tire
A rubber composition comprising, per 100 parts by mass of a total amount of a rubber component, 0.1 to 10 parts by mass of a compound represented by the following general formula (1): wherein at least one of R 1 to R 5 is an —OH group or an —OCH 3 group and others are each an —H group or a hydrocarbon group having 1 to 20 carbon atoms, A is an unsaturated bond or an alkylene group having 1 to 20 carbon atoms and optionally having an —H group, a —CH 3 group, an —NH 2 group, an —O— group, or an —OH group, n is an integer of 0 to 10, and B is a —COOH group, an —OH group, or an ═O group and optionally forms a ring structure with adjacent R 1 or R 5 .
1 . A pneumatic tire comprising a rubber part containing a vulcanized rubber of a rubber composition consisting of, per 100 parts by mass of a total amount of a rubber component, 0.1 to 10 parts by mass of a compound represented by the following general formula (1):
wherein at least one of R 1 to R 5 is an —OH group or an —OCH 3 group and others are each an —H group or a hydrocarbon group having 1 to 20 carbon atoms, A is an unsaturated bond or an alkylene group having 1 to 20 carbon atoms and optionally having an —H group, a —CH 3 group, an —NH 2 group, an —O— group, or an —OH group, n is an integer of 0 to 10, and B is a —COOH group, an —OH group, or an ═O group and optionally forms a ring structure with adjacent R 1 or R 5 , wherein the compound represented by the general formula (1) is at least one of 3,4-dihydroxycinnamic acid and 3,4-dimethoxycinnamic acid, and an amount of at least one of 3,4-dihydroxycinnamic acid and 3,4-dimethoxycinnamic acid is 1 to 10 phr, and optionally carbon black, silica, a vulcanizing agent, a vulcanizing accelerator, an antiaging agent other than the compound represented by Formula (1), stearic acid, a softener and a processing aid.
2 . The pneumatic tire according to claim 1 , wherein the compound represented by the general formula (1) is a naturally occurring compound.
3 . The pneumatic tire according to claim 1 , wherein the antiaging agent other than the compound represented by Formula (1) is selected from the group consisting of an aromatic amine-based antiaging agent, an amine-ketone-based antiaging agent, a monophenol-based antiaging agent, a bisphenol-based antiaging agent, a polyphenol-based antiaging agent, a dithiocarbamic acid salt-based antiaging agent, and a thiourea-based antiaging agent.
4 . The pneumatic tire according to claim 1 , wherein the vulcanizing agent is sulfur.
5 . The pneumatic tire according to claim 1 , wherein the vulcanizing accelerator is selected from the group consisting of a sulfenamide-based vulcanization accelerator, a thiuram-based vulcanization accelerator, a thiazole-based vulcanization accelerator, a thiourea-based vulcanization accelerator, a guanidine-based vulcanization accelerator, and a dithiocarbamate-based vulcanization accelerator.