Method of production of conjugated diene rubber
Production of a conjugated diene rubber includes polymerizing isoprene or a monomer mixture containing isoprene and an aromatic vinyl monomer in an inert solvent by using a polymerization initiator so as to form a polymer block (A) having an active end, mixing the polymer block (A) having an active end and 1,3-butadiene or a monomer mixture containing 1,3-butadiene and an aromatic vinyl monomer to continue a polymerization reaction so as to obtain a conjugated diene polymer chain having an active end and containing a polymer block (A) and a polymer block (B), and reacting a compound represented by the following general formula (1) with the active end of the conjugated diene polymer chain having an active end:
1. A method of production of a conjugated diene rubber comprising
a step of polymerizing isoprene or a monomer mixture containing isoprene and an aromatic vinyl monomer in an inert solvent by using a polymerization initiator so as to form a polymer block (A) having an active end and containing 80 to 100 wt % of isoprene monomer units and 0 to 20 wt % of aromatic vinyl monomer units,
a step of mixing the polymer block (A) having an active end and 1,3-butadiene or a monomer mixture containing 1,3-butadiene and an aromatic vinyl monomer to continue a polymerization reaction and forming a polymer block (B) having an active end and containing 50 to 100 wt % of 1,3-butadiene monomer units and 0 to 50 wt % of aromatic vinyl monomer units as a continuation of the polymer block (A) so as to obtain a conjugated diene polymer chain having an active end, and
a step of reacting a compound represented by the following general formula (1) with the active end of the conjugated diene polymer chain having an active end:
wherein, in the general formula (1), X 1 represents a functional group selected from a hydrocarbyloxy group, halogen group, and hydroxyl group, R 1 represents a substituted or unsubstituted hydrocarbon group, each of R 2 and R 3 independently represents a substituted or unsubstituted hydrocarbon group, R 2 and R 3 may bond with each other to form a ring structure together with the nitrogen atom represented by “N” in the general formula (1), and, when forming the ring structure, R 2 and R 3 may form a ring structure together with a hetero atom other than the nitrogen atom represented by the “N” in addition to the nitrogen atom represented by the “N”, “r” is an integer of 0 to 2.
2. The method of production of a conjugated diene rubber according to claim 1 further comprising, after obtaining the conjugated diene polymer chain having an active end, a step of reacting part of the active ends with a tin halide, silicon halide, or compound represented by the general formula (2):
(X 2 3 M-R 4 -M X 2 ) 3 (2)
wherein, in the general formula (2), R 4 represents a substituted or unsubstituted bivalent hydrocarbon group, X 2 represents a halogen group, and M represents a silicon atom or tin atom.
3. The method of production of a conjugated diene rubber according to claim 1 wherein in the conjugated diene polymer chain having an active end, a weight ratio of the polymer block (A) and polymer block (B) is, by (weight of polymer block (A))/(weight of polymer block (B)), 0.001 to 0.1.
4. The method of production of a conjugated diene rubber according to claim 1 wherein, in the general formula (1), R 2 and R 3 bond with each other to form a piperazine ring structure together with the nitrogen atom represented by the “N” in the general formula (1).
5. A conjugated diene rubber obtained by the method of production according to claim 1 .
6. A rubber composition comprising 100 parts by weight of a rubber component containing the conjugated diene rubber according to claim 5 and 10 to 200 parts by weight of silica.
7. The rubber composition according to claim 6 further comprising a cross-linking agent.
8. A cross-linked rubber obtained by cross-linking the rubber composition according to claim 7 .
9. A tire including the cross-linked rubber according to claim 8 .