Abstract: The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in hardness over time. The present invention relates to a rubber composition containing a copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber composition having a heat aging resistance index defined by equation (1) of 10 or less.

Abstract: The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in complex modulus E* over time. The present invention relates to rubber compositions containing at least one copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber compositions having a heat aging resistance index defined by equation (1) of 27 or less.

Abstract: The present invention provides pneumatic tires which have reduced changes in hardness over time and which provide improved abrasion resistance while ensuring good durability. The present invention relates to a pneumatic tire formed from a rubber composition, the rubber composition containing: a rubber component including a hydrogenated copolymer containing a structural unit derived from an aromatic vinyl compound and a structural unit derived from a conjugated diene compound; and a liquid polymer having a number average molecular weight of 2,500 to 500,000, the hydrogenated copolymer being present in an amount of 80% by mass or less based on 100% by mass of the rubber component, the liquid polymer being present in an amount of 1 to 50 parts by mass per 100 parts by mass of the rubber component.

Abstract: The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in tan ? over time. The present invention relates to rubber compositions containing at least one copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber compositions having a heat aging resistance index defined by equation (1) of 2.0 or less.

Abstract: A triazine ring-containing polymer having a high refractive index and a low birefringence, and being capable of being subjected to injection molding, wherein the polymer having a repeating unit of *-[A-B-]-*, including a structural unit A derived from a triazinedithiol compound, and a structural unit B including an aromatic hydrocarbon group; and a thermoplastic resin, a thermoplastic article, and an optical part including the polymer.

Abstract: The di(meth)acrylate compound of the present disclosure is represented by the following formula (1): wherein Z1a and Z1b each represent an arene ring, R1a and R1b each represent a substituent, k1 and k2 each denote an integer of not less than 0, m1 and m2 each denote an integer of 0 to 4, and at least one of m1 and m2 denotes 1 or more, R2a and R2b each represent a substituent, n1 and n2 each denote an integer of 0 to 4, m1+n1 and m2+n2 each denote 4 or less, A1a and A1b each represent a straight- or branched-chain alkylene group, A2a and A2b each represent a straight- or branched-chain alkylene group, p1 and p2 each denote an integer of not less than 0, and R3a and R3b each represent a hydrogen atom or a methyl group. The di(meth)acrylate compound is a novel compound having a high refractive index.

Abstract: Provided are a rubber composition which provides a self-healing rubber with improved strength and wet grip performance, and a pneumatic tire including the rubber composition. The present disclosure relates to a rubber composition containing a rubber component having a functional group containing a cationic functional group and/or an anionic functional group, a filler capable of generating a charge paired with the functional group, and sulfur.

Abstract: The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in tan ? over time. The present invention relates to rubber compositions containing at least one copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber compositions having a heat aging resistance index defined by equation (1) of 2.0 or less.

Abstract: The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in complex modulus E* over time. The present invention relates to rubber compositions containing at least one copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber compositions having a heat aging resistance index defined by equation (1) of 27 or less.

Abstract: The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in hardness over time. The present invention relates to a rubber composition containing a copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber composition having a heat aging resistance index defined by equation (1) of 10 or less.

Abstract: The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in tan ? peak temperature over time. The present invention relates to rubber compositions containing at least one copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber compositions having a heat aging resistance index defined by equation (1) of 0.45 or less.

Abstract: The present invention provides pneumatic tires which have reduced changes in hardness over time and which provide improved abrasion resistance while ensuring good durability. The present invention relates to a pneumatic tire formed from a rubber composition, the rubber composition containing: a rubber component including a hydrogenated copolymer containing a structural unit derived from an aromatic vinyl compound and a structural unit derived from a conjugated diene compound; and a liquid polymer having a number average molecular weight of 2,500 to 500,000, the hydrogenated copolymer being present in an amount of 80% by mass or less based on 100% by mass of the rubber component, the liquid polymer being present in an amount of 1 to 50 parts by mass per 100 parts by mass of the rubber component.