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

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 X4, X5, and X6 independently denote a group of formula (VIa), a hydrocarbyl group, or a substituted hydrocarbyl group, and at least one of X4, X5, and X6 is a group of formula (VIa),
• wherein R3 and R4 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 R3 and R4 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 R31 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, R32 and R33 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, R32 and R33 may be bonded so as to form, together with the nitrogen atom, a ring structure, and R32 and R33 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 R41 and R42 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 R43 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, Y1 denotes a nitrogen atom-containing group as a substituent on the benzene ring, and when there are a plurality of Y1s, the plurality of Y1s 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, Y2 and Y3 denote nitrogen atom-containing groups as substituents on the benzene rings, when there are a plurality of Y2s the plurality of Y2s may be identical to or different from each other, and when there are a plurality of Y3s the plurality of Y3s may be identical to or different from each other.