Diene elastomer compositions

摘要

Disclosed is a diene elastomer composition especially suitable as tread rubber of tires which has low rolling resistance and high wet grip in combination. This elastomer composition contains a rubber material comprising an elastomeric polymer component of a butadiene polymer and/or a styrene-butadiene copolymer and a rubbery component. The elastomeric polymer is produced by using an organolithium compound as a polymerization initiator, and has a long chain end concentration (LCEC) of 1.5 or less as defined by the following formula: <IMAGE> wherein alpha : total number of terminal groups in long chain molecules per polymer, &upbar& M: a value obtained from intrinsic viscosity of the polymer as measured in toluene at 30 DEG C. by the following formulas: &upbar& M=70,660 x[ eta ]1.282 for styrene-butadiene copolymer, &upbar& M=79,167 x[ eta ]1.443 for butadiene polymer, beta i: weight fraction of component i when &upbar& M=( &upbar& M)i.