CONJUGATED DIENE RUBBER COMPOSITIONS, PROCESS FOR PRODUCTION OF THE SAME AND PRODUCTS OF CROSSLINKING THEREOF

A conjugated diene rubber composition comprising (A) 5-95 wt.% of a conjugated diene rubber having a structure such that at least three conjugated diene polymer chains are bonded together through a specific polyorganosiloxane having groups containing alkylene glycol repeating units and (B) 95-5 wt.% of a conjugated diene rubber having reacted with a compound having in the molecule a functional group selected from >C=O, >C=S, amino, imino, epoxy, pyridyl, alkoxyl and halogeno. This rubber composition gives, when silica is incorporated therein, a vulcanizable rubber composition having good processability and giving a rubber vulcanizate exhibiting sufficiently reduced heat build up, and having good wet-grip property and good abrasion resistance.