Modified conjugated diene polymer, and polymer composition containing said polymer

1. A modified conjugated diene polymer including a structural unit derived from a compound represented by formula (1) and a structural unit derived from a conjugated diene

wherein in formula (1),

α and β represent integers such that 1≤α≤5, 1≤β≤5 and 2≤α+β≤6 are satisfied,

n represents 0 or 1,

(i) when n is 0,

R 11 , R 12 , R 13 , R 16 , R 17 and R 18 each independently represent a hydrocarbyl group, substituted amino group, hydroxy group or hydrocarbyloxy group,

from among R 11 , R 12 , R 13 , R 16 , R 17 and R 18 , at least two are substituted amino groups and at least one is a hydroxy group or hydrocarbyloxy group,

two groups selected from among R 11 , R 12 , R 13 , R 16 , R 17 and R 18 are optionally bonded either directly or indirectly at positions where a hydrogen atom has been removed from each group,

R 15 represents an (α+β)-valent group resulting from removal of (α+β) hydrogen atoms from a hydrocarbon,

(ii) when n is 1,

R 11 , R 12 , R 13 , R 16 , R 17 and R 18 each independently represent a hydrocarbyl group, substituted amino group, hydroxy group or hydrocarbyloxy group,

R 14 represents:

(a) a group resulting from removal of two hydrogen atoms from a hydrocarbon with an amino group or substituted amino group,

(b) a group resulting from removal of two hydrogen atoms from a hydrocarbon with a substituent including a heteroatom other than a nitrogen atom, or

(c) a hydrocarbylene group,

when R 14 is (a) a group resulting from removal of two hydrogen atoms from a hydrocarbon with an amino group or substituted amino group, from among R 11 , R 12 , R 13 , R 16 , R 17 and R 18 , at least one is a substituted amino group and at least one is a hydroxy group or hydrocarbyloxy group,

when R 14 is (b) a group resulting from removal of two hydrogen atoms from a hydrocarbon with a substituent including a heteroatom other than a nitrogen atom, or (c) a hydrocarbylene group, from among R 11 , R 12 , R 13 , R 16 , R 17 and R 18 , at least two are substituted amino groups and at least one is a hydroxy group or hydrocarbyloxy group,

at least two groups from among R 11 , R 12 , R 13 , R 14 , R 16 , R 17 and R 18 are optionally bonded either directly or indirectly at positions where a hydrogen atom has been removed from each group, and

R 15 represents an (α+β)-valent group resulting from removal of (α+β) hydrogen atoms from a hydrocarbon,

wherein the modified conjugated diene polymer has a molecular chain which is a conjugated diene polymer including a structural unit derived from the conjugated diene, and the structural unit derived from the compound represented by formula (1) is chemically bound to one or both ends of the molecular chain of the modified conjugated diene polymer or is chemically bound as a side chain on the molecular chain of the modified conjugated diene polymer.

2. The modified conjugated diene polymer according to claim 1 , wherein in formula (1), n is 0, α is 1, β is 1 and R 15 is a hydrocarbylene group of 1 to 20 carbon atoms.

3. A modified conjugated diene polymer according to claim 1 , wherein the compound represented by formula (1) is at least one kind of compound selected from the group consisting of 2-(bis(diethylamino)methylsilyl)-1-(dimethoxymethylsilyl)ethane and 2-(bis(diethylamino)methylsilyl)-1-(trimethoxysilyl)ethane, respectively.

4. A modified conjugated diene polymer composition containing the modified conjugated diene polymer according to claim 1 and a reinforcing agent, wherein the content of the reinforcing agent is 10 parts by mass or greater and 150 parts by mass or lower, with respect to 100 parts by mass of the modified conjugated diene polymer.

5. A tire including the modified conjugated diene polymer composition according to claim 4 , or its vulcanizate.