Rubber composition for tires, and pneumatic tire
The present invention provides a rubber composition for tires which can improve crack resistance, ozone resistance, discoloration resistance, and tire appearance while maintaining a good balance between them, and also provides a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition for tires, containing a rubber component having a combined content of polybutadiene rubber, natural rubber, and polyisoprene rubber of 80% by mass or more per 100% by mass of the rubber component, the rubber composition containing, per 100 parts by mass of the rubber component: 0.1 to 8.0 parts by mass of polyether (A) having a glycol ether content of 80% by mass or more and a HLB of 3.5 to 19.0, the polyether (A) excluding Pluronic nonionic surfactants; 2 to 70 parts by mass of carbon black; and 0.3 to 7.0 parts by mass of an antioxidant.
1. A pneumatic tire, comprising a tire component, said tire component being formed from a rubber composition, said rubber composition comprising a rubber component having a combined content of polybutadiene rubber, natural rubber, and polyisoprene rubber of 80% by mass or more per 100% by mass of the rubber component,
the rubber composition comprising, per 100 parts by mass of the rubber component:
0.1 to 8.0 parts by mass of a polyether (A) having a glycol ether content of 80% by mass or more and a HLB of 3.5 to 19.0, the polyether (A) excluding Pluronic nonionic surfactants;
2 to 70 parts by mass of carbon black; and
0.3 to 7.0 parts by mass of an antioxidant,
wherein the polyether (A) is represented by R 1 —O—(R 2 —O) n —R 3 or R 4 —{O—(R 2 —O) n —R 1 } m ,
wherein R 1 represents a hydrogen atom;
wherein each R 2 is the same as or different from each other and represents a C2-C10 divalent aliphatic hydrocarbon or divalent alicyclic hydrocarbon group in which a hydrogen atom bound to a carbon atom is optionally replaced with an aromatic hydrocarbon group;
wherein R 3 represents a C1-C20 aliphatic hydrocarbon, alicyclic hydrocarbon, aromatic hydrocarbon, or alkanoyl group in which a hydrogen atom bound to a carbon atom is optionally replaced with an aromatic hydrocarbon group;
wherein R 4 represents a residue that is compound (a) having three or more hydroxyl groups from which the hydroxyl groups are removed; and
wherein n and m represent integers which are not limited as long as the HLB and the glycol ether content fall within the respective ranges indicated above.
2. The pneumatic tire according to claim 1 ,
wherein the polyether (A) has a number average molecular weight of 1,500 to 50,000.
3. The pneumatic tire according to claim 1 ,
wherein the polyether (A) has a HLB of 4.0 to 17.5.
4. The pneumatic tire according to claim 1 ,
wherein the polyether (A) has a number average molecular weight of 2,000 to 40,000.
5. The pneumatic tire according to claim 1 ,
wherein the tire component is at least one of a sidewall, clinch, or wing.
6. The pneumatic tire according to claim 2 ,
wherein the polyether (A) has a HLB of 4.0 to 17.5.
7. The pneumatic tire according to claim 2 ,
wherein the polyether (A) has a number average molecular weight of 2,000 to 40,000.
8. The pneumatic tire according to claim 3 ,
wherein the polyether (A) has a number average molecular weight of 2,000 to 40,000.