Conjugated diene polymer, conjugated diene polymer composition, and method for producing conjugated diene polymer

1. A conjugated diene polymer comprising a conjugated diene-based constituent unit and a constituent unit of formula (I), at least one terminus of the polymer being modified by a compound which is a carboxylic acid amide compound of formula (III) as defined below,

wherein X 1 , X 2 , and X 3 independently denote a group of formula (Ia), a hydroxy group, a hydrocarbyl group, or a substituted hydrocarbyl group, and at least one of X 1 , X 2 , and X 3 is a hydroxy group or a group of formula (Ia),

wherein R 1 and R 2 independently denote a hydrocarbyl group having 1 to 6 carbon atoms, a substituted hydrocarbyl group having 1 to 6 carbon atoms, a silyl group, or a substituted silyl group, and R 1 and R 2 may be bonded so as to form, together with the nitrogen atom, a ring structure,

wherein R 31 denotes a hydrogen atom, a hydrocarbyl group having 1 to 10 carbon atoms, a substituted hydrocarbyl group having 1 to 10 carbon atoms, or a heterocyclic group having a nitrogen atom and/or an oxygen atom as a heteroatom, R 32 and R 33 independently denote a group having 1 to 10 carbon atoms, which may have at least one atom selected from the atomic group consisting of a nitrogen atom, an oxygen atom, and a silicon atom, R 32 and R 33 may be bonded so as to form, together with the nitrogen atom, a ring structure, and R 32 and R 33 may be a single group bonded to the nitrogen via a double bond, or

at least one compound selected from the compound group consisting of a compound of formula (IVa) and a compound of formula (IVb):

wherein m denotes an integer of 0 to 10, and R 41 and R 42 independently denote a hydrocarbyl group having 1 to 20 carbon atoms or a substituted hydrocarbyl group having 1 to 20 carbon atoms,

wherein n denotes an integer of 0 to 10, and R 43 denotes a hydrocarbyl group having 1 to 20 carbon atoms or a substituted hydrocarbyl group having 1 to 20 carbon atoms, or

at least one compound selected from the compound group consisting of a compound of formula (IVc) and a compound of formula (IVd):

wherein r denotes an integer of 1 or 2, Y 1 denotes a nitrogen atom-containing group as a substituent on the benzene ring, and when there are a plurality of Y 1 s, the plurality of Y 1 s may be identical to or different from each other,

wherein s denotes an integer of 1 or 2, t denotes an integer of 0 to 2, Y 2 and Y 3 denote nitrogen atom-containing groups as substituents on the benzene rings, when there are a plurality of Y 2 s the plurality of Y 2 s may be identical to or different from each other, and when there are a plurality of Y 3 s the plurality of Y 3 s may be identical to or different from each other.

2. The polymer according to claim 1 , wherein R 1 and R 2 in formula (Ia) are hydrocarbyl groups having 1 to 6 carbon atoms.

3. The polymer according to claim 1 , wherein two of X 1 , X 2 , and X 3 in formula (I) are groups of formula (Ia) or hydroxy groups.

4. The polymer according to claim 1 , wherein the vinyl bond content of the conjugated diene polymer, with the content of the conjugated diene-based constituent unit as 100 mole %, is not less than 20 mole % and not more than 70 mole %.

5. A conjugated diene polymer composition comprising the polymer according to claim 1 and a filler.

6. The composition according to claim 5 , wherein the filler content is 10 to 150 parts by weight per 100 parts by weight of the conjugated diene polymer content.

7. A method for producing a conjugated diene polymer, comprising steps A and B:

step A: polymerizing monomers comprising a conjugated diene and a vinyl compound of formula (VI) in a hydrocarbon solvent in the presence of an alkali metal catalyst to produce a polymer having an alkali metal originating from the catalyst at at least one terminus of a polymer chain comprising a conjugated diene-based monomer unit and a monomer unit based on the vinyl compound of formula (VI),

wherein X 4 , X 5 , and X 6 independently denote a group of formula (VIa), a hydrocarbyl group, or a substituted hydrocarbyl group, and at least one of X 4 , X 5 , and X 6 is a group of formula (VIa),

wherein R 3 and R 4 independently denote a hydrocarbyl group having 1 to 6 carbon atoms, a substituted hydrocarbyl group having 1 to 6 carbon atoms, a silyl group, or a substituted silyl group, and R 3 and R 4 may be bonded so as to form, together with the nitrogen atom, a ring structure, and

step B: reacting the resulting polymer in step A with a compound which is a carboxylic acid amide compound of formula (III) as defined below,

wherein R 31 denotes a hydrogen atom, a hydrocarbyl group having 1 to 10 carbon atoms, a substituted hydrocarbyl group having 1 to 10 carbon atoms, or a heterocyclic group having a nitrogen atom and/or an oxygen atom as a heteroatom, R 32 and R 33 independently denote a group having 1 to 10 carbon atoms, which may have at least one atom selected from the atomic group consisting of a nitrogen atom, an oxygen atom, and a silicon atom, R 32 and R 33 may be bonded so as to form, together with the nitrogen atom, a ring structure, and R 32 and R 33 may be a single group bonded to the nitrogen via a double bond, or

at least one compound selected from the compound group consisting of a compound of formula (IVa) and a compound of formula (IVb):

wherein m denotes an integer of 0 to 10, and R 41 and R 42 independently denote a hydrocarbyl group having 1 to 20 carbon atoms or a substituted hydrocarbyl group having 1 to 20 carbon atoms,

wherein n denotes an integer of 0 to 10, and R 43 denotes a hydrocarbyl group having 1 to 20 carbon atoms or a substituted hydrocarbyl group having 1 to 20 carbon atoms, or at least one compound selected from the compound group consisting of a compound of formula (IVc) and a compound of formula (IVd):

wherein r denotes an integer of 1 or 2, Y 1 denotes a nitrogen atom-containing group as a substituent on the benzene ring, and when there are a plurality of Y 1 s, the plurality of Y 1 s may be identical to or different from each other,

wherein s denotes an integer of 1 or 2, t denotes an integer of 0 to 2, Y 2 and Y 3 denote nitrogen atom-containing groups as substituents on the benzene rings, when there are a plurality of Y 2 s the plurality of Y 2 s may be identical to or different from each other, and when there are a plurality of Y 3 s the plurality of Y 3 s may be identical to or different from each other.

8. The method according to claim 7 , wherein R 3 and R 4 in formula (VIa) are hydrocarbyl groups having 1 to 6 carbon atoms.

9. The method according to claim 7 , wherein two of X 4 , X 5 , and X 6 of formula (VI) are groups of formula (VIa).