Conjugated diene polymer rubber, and conjugated diene polymer rubber composition

A method for producing a conjugated diene polymer rubber,

• the conjugated diene polymer rubber comprising component (A) and component (B) below, the component (A) having a content, with the total amount of the component (A) and the component (B) as 100% by weight, of from 5 to 90% by weight, and the component (B) having a content of from 95 to 10% by weight,
• wherein the component (A) is produced by a process comprising steps A and B:
• step A:
• copolymerizing a monomer component including a conjugated diene and a vinyl monomer represented by formula (X) below in a hydrocarbon solvent in the presence of an alkali metal catalyst,
• wherein X1, X2, and X3 denote an optionally substituted hydrocarbyl group or a group represented by formula (Xa) below, and at least one of X1, X2, and X3 is a group represented by formula (Xa) below,
• wherein R′ and R″ denote a hydrocarbyl group having 1 to 6 carbon atoms that may contain at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom, and a silicon atom, a silyl group, a substituted silyl group, or a divalent group having 2 to 12 carbon atoms in which R′ and R″ are bonded to each other, and * represents a bonding position, and
• step B:
• reacting the resulting polymer in step A with a carbonyl group- and substituted amino group-containing compound, and
• wherein the component (B) is produced by a process comprising steps C and D:
• step C:
• copolymerizing a monomer component including a conjugated diene and a vinyl monomer represented by formula (X) above in a hydrocarbon solvent in the presence of an alkali metal catalyst, and
• step D:
• reacting the resulting polymer in step C with a compound represented by formula (IIa) below,
• (R21O)mSi(R22A)nR234-m-n (IIa)
• wherein m denotes a number from 1 to 3, n denotes a number from 1 to 3, m+n is from 2 to 4, R21 and R23 denote a hydrocarbyl group, R22 denotes a hydrocarbylene group, A denotes a substituted amino group or an optionally substituted hydrocarbyloxy group, when there are a plurality of R21s the plurality of R21s may be identical to or different from each other, when there are a plurality of R22s the plurality of R22s may be identical to or different from each other, when there are a plurality of R23s the plurality of R23s may be identical to or different from each other, and when there are a plurality of As the plurality of As may be identical to or different from each other.