| abstract |
A diene rubber (A) having a weight average molecular weight (Mw) of 100,000 to 3,000,000, an Mw/number average molecular weight (Mn) ratio of 1.30 to 2.50, and an Mw/peak top molecular weight (Mp) ratio 0.70 to 1.30. A rubber composition comprising the diene rubber (A) and a diene rubber (B) having an Mw of 2,000 to 90,0000 and/or an oil extender for rubber has good processability and can give a rubber vulcanizate having high tensile strength and good abrasion resistance. The diene rubber (A) is produced by conducting a living polymerization of diene monomer in a hydrocarbon solvent; adding a polymerization stopper to a polymerization mixture at a conversion of 5 to 98% to deactivate 10 to 90% by mole of active terminals present as of the initiation of polymerization; and finally adding a polymerization stopper to completely terminate the polymerization reaction. |