Tire member, hydrogenated conjugated diene polymer, and polymer composition
Provided is a tire member which is satisfactory in low fuel consumption performance and exhibits higher strength and more excellent abrasion resistance as compared with conventional ones. The tire member is a tire member obtained by subjecting a composition containing a hydrogenated conjugated diene polymer and a crosslinking agent to a crosslinking treatment, wherein the hydrogenated conjugated diene polymer is a hydrogenated product of a conjugated diene polymer that has a structural unit derived from butadiene and has a functional group at one end or both ends and the functional group is one or more groups selected from the group consisting of an amino group, an imino group, a pyridyl group, a phosphino group, a thiol group, and a hydrocarbyloxysilyl group.
1. A tire member obtained by subjecting a composition comprising a hydrogenated conjugated diene polymer and a crosslinking agent to a crosslinking treatment,
wherein the hydrogenated conjugated diene polymer is a hydrogenated product of a conjugated diene polymer which comprises: a structural unit derived from butadiene; a structural unit derived from styrene; and a functional group attached at one end or both ends of the conjugated diene polymer, the functional group being one or more groups selected from the group consisting of an amino group, an imino group, a pyridyl group, a phosphino group, a thiol group, and a hydrocarbyloxysilyl group; and
wherein the hydrogenation rate of the structural unit derived from butadiene of the hydrogenated conjugated diene polymer is 90% or more.
2. The tire member according to claim 1 , wherein the hydrogenated conjugated diene polymer comprises a structure represented by the following general formula (1-1) as a structure containing the functional group at the end(s):
wherein A 4 is a functional group which has one or more atoms selected from the group consisting of N, P, and S and in which a part or all of the one or more atoms are optionally protected with a hydrocarbylsiliy group and the atom bonding to R 5 is N, P, or S; R 3 is a hydrocarbyl group and n is 0 to 2; R 5 is a hydrocarbylene group; R 6 is a hydrogen atom or a hydrocarbyl group; and R 3 's and R 6 's existing in plurality are each the same or different.
3. The tire member according to claim 1 , wherein, in the hydrogenated conjugated diene polymer, a chain composed of the structural units derived from styrene ranging in an amount of 8 or more units is contained in a ratio of 10% by mass or less relative to the whole of the structural units derived from styrene.
4. The tire member according to claim 1 , wherein the hydrogenated conjugated diene polymer comprises a structural unit derived from a conjugated diene compound other than butadiene.
5. The tire member according to claim 4 , wherein the conjugated diene compound other than butadiene is isoprene.
6. The tire member according to claim 1 , wherein the hydrogenated conjugated diene polymer is a hydrogenated product of a polymer obtained by polymerizing monomers including 50 to 90 parts by mass of butadiene, 10 to 50 parts by mass of styrene, and 0 to 40 parts by mass of a conjugated diene compound other than butadiene.
7. The tire member according to claim 1 , wherein 1,2-vinyl content in the structural unit derived from butadiene in the conjugated diene polymer obtained by polymerizing monomer(s) including butadiene is from 5 to 70%.
8. The tire member according to claim 1 , wherein the hydrogenated conjugated diene polymer comprises a polyisoprene block.
9. The tire member according to claim 8 , wherein the ratio of 1,4-bond/3,4-bond of the polyisoprene block ranges from 60/40 to 98/2.
10. The tire member according to claim 1 , wherein the composition further comprises one or more selected from silica and carbon black.
11. The tire member according to claim 1 , wherein the tire member is a tread.
12. The tire member according to claim 1 , wherein the tire member is a side wall.
13. A hydrogenated conjugated diene polymer, which is a hydrogenated product of a conjugated diene polymer, comprising: a polymer block which comprises a structural unit derived from butadiene and a structural unit derived from styrene; a polyisoprene block at one end or both end of the polymer block; and a functional group attached at one end or both ends of the polymer chain of the conjugated diene polymer, the functional group being at least one group selected from the group consisting of an amino group, an imino group, a pyridyl group, a phosphino group, a thiol group, and a hydrocarbyloxysilyl group;
wherein the hydrogenation rate of the structural unit derived from butadiene of the hydrogenated conjugated diene polymer is 90% or more.
14. The hydrogenated conjugated diene polymer according to claim 13 , wherein the hydrogenated conjugated diene polymer comprises a structure represented by the following general formula (1-1) as a structure containing the functional group at the end(s) of the polymer chain:
wherein A 4 is a functional group which has one or more atoms selected from the group consisting of N, P, and S and in which a part or all of the one or more atoms are optionally protected with a hydrocarbylsiliy group and the atom bonding to R 5 is N, P, or S; R 3 is a hydrocarbyl group and n is 0 to 2; R 5 is a hydrocarbylene group; R 6 is a hydrogen atom or a hydrocarbyl group; and R 3 's and R 6 's existing in plurality are each the same or different.
15. The hydrogenated conjugated diene polymer according to claim 13 , wherein a chain composed of the structural units derived from styrene ranging in an amount of 8 or more units is contained in a ratio of 10% by mass or less relative to the whole of the structural units derived from styrene.
16. The hydrogenated conjugated diene polymer according to claim 13 , wherein the hydrogenated conjugated diene polymer is a hydrogenated product of a polymer obtained by polymerizing monomers including 50 to 90 parts by mass of butadiene, 10 to 50 parts by mass of styrene, and 0 to 40 parts by mass of a conjugated diene compound other than butadiene.
17. The hydrogenated conjugated diene polymer according to claim 13 , wherein 1,2-vinyl content in the structural unit derived from butadiene in the conjugated diene polymer obtained by polymerizing monomer(s) including butadiene is from 5 to 70%.
18. The hydrogenated conjugated diene polymer according to claim 13 , wherein the ratio of 1,4-bond/3,4-bond of the polyisoprene block is from 60/40 to 98/2.
19. A polymer composition for tire member formation, comprising: the hydrogenated conjugated diene polymer according to claim 13 ; and a crosslinking agent.
20. The tire member according to claim 1 , wherein conjugated diene polymer comprises a polymer block which comprises the structural unit derived from butadiene and the structural unit derived from styrene, and further comprises a polyisoprene block at one end or both end of the polymer block.