Rubber composition, crosslinked product, and tire
A rubber composition contains: (A) a polymer having a carbon-carbon unsaturated bond and exhibiting a value α of 0.6 or more as obtained by the following formula (i): α=( p +(0.5× r ))/( p+q +(0.5× r )+ s ) (i) wherein p, q, r, and s are the proportions by mole of structural units represented by the following formulae (1), (2), (3), and (4), respectively in the polymer: and (B) modified silica.
1. A rubber composition, comprising:
(A) a polymer comprising a carbon-carbon unsaturated bond and exhibiting a value α of 0.6 or more as obtained by formula (i):
α=( p +(0.5× r ))/{ p+q +(0.5× r )+ s ) (i),
p, q, r, and s being proportions by mole of structural units of formulae (1), (2), (3), and (4), respectively in the polymer:
and
(B) modified silica
wherein the polymer (A) also exhibits a value β of 0.6 or less as obtained by formula (ii):
β=( p+q )/( p+q +(0.5× r )+ s ) (ii),
p, q, r, and s having the same meanings as in formula (i).
2. The composition of claim 1 , wherein the polymer (A) exhibits a value β in a range of from 0.17 to 0.58 as obtained by the formula (ii).
3. The composition of claim 1 , wherein the modified silica (B) has at least one group selected from the group consisting of an amino group, an amido group, a carboxy group, a hydrocarbyloxycarbonyl group, a mercapto group, and a (poly)sulfide group.
4. The composition of claim 1 , wherein the polymer (A) has an average ethylene chain length in a range of from 2 to 20, and
wherein a mass ratio of the amount Ma of the polymer (A) to the amount Mb of the modified silica (B), Ma/Mb, is in a range of from 0.4 to 1.5.
5. The composition of claim 1 , further comprising:
a rubber component different from the polymer (A),
wherein an amount of the polymer (A) is 30 mass % or more, relative to total rubber components in the rubber composition.
6. The composition of claim 1 , wherein the polymer (A) further comprises a structural unit derived from an aromatic vinyl compound.
7. The composition of claim 1 , wherein the polymer (A) is obtained by a process comprising reacting a conjugated diene-based polymer having an active terminal and a compound having a functional group capable of reacting with the active terminal and a functional group that interacts with silica.
8. A crosslinked product, obtained through crosslinking of the rubber composition of claim 1 .
9. A tire, comprising:
a tread; and
a sidewall,
wherein the tread, the sidewall, or both comprise the crosslinked product of claim 8 .
10. The composition of claim 1 , wherein the modified silica (B) comprises an amino group, an amido group, a carboxy group, a hydrocarbyloxycarbonyl group, a mercapto group, and/or a (poly)sulfide group.
11. A rubber composition, comprising:
(A) a polymer comprising a carbon-carbon unsaturated bond and exhibiting a value α of 0.6 or more as obtained by formula (i):
α=( p +(0.5× r ))/( p+q +(0.5× r )+ s ) (i),
p, q, r, and s being proportions by mole of structural units of formulae (1), (2), (3), and (4), respectively in the polymer:
and
(B) modified silica,
wherein the polymer (A) has an average ethylene chain length in a range of from 2 to 20, and
wherein a mass ratio of the amount Ma of the polymer (A) to the amount Mb of the modified silica (B), Ma/Mb, is in a range of from 0.4 to 1.5.
12. The composition of claim 11 , wherein the polymer (A) also exhibits a value β in a range of from 0.6 or less as obtained by formula (ii):
β=( p+q )/( p+q +(0.5× r )+ s ) (ii),
wherein p, q, r, and s have the same meanings as defined in the formula (i).
13. The composition of claim 11 , wherein the modified silica (B) has at least one group selected from the group consisting of an amino group, an amido group, a carboxy group, a hydrocarbyloxycarbonyl group, a mercapto group, and a (poly)sulfide group.
14. The composition of claim 11 , wherein the modified silica (B) comprises an amino group, an amido group, a carboxy group, a hydrocarbyloxycarbonyl group, a mercapto group, and/or a (poly)sulfide group.
15. The composition of claim 11 , further comprising:
a rubber component different from the polymer (A),
wherein an amount of the polymer (A) is 30 mass % or more, relative to total rubber components in the rubber composition.
16. The composition of claim 11 , wherein the polymer (A) further comprises a structural unit derived from an aromatic vinyl compound.
17. The composition of claim 11 , wherein the polymer (A) is obtained by a process comprising reacting a conjugated diene-based polymer having an active terminal and a compound having a functional group capable of reacting with the active terminal and a functional group that interacts with silica.
18. A crosslinked product, obtained through crosslinking of the rubber composition of claim 11 .
19. A tire, comprising:
a tread; and
a sidewall,
wherein the tread, the sidewall, or both comprises the crosslinked product of claim 18 .
20. The composition of claim 4 , wherein the average ethylene chain length of the polymer (A) is in a range of from 2.2 to 15, and
wherein the mass ratio, Ma/Mb, is in a range of from 0.6 to 1.5.