Abstract: A composition for tires containing at least 30% star shaped random styrene-butadiene copolymer obtained by solution polymerization, having a styrene content of less than 20% and more than 10% and a vinyl content of less than 50% and more than 40%, the composition value X of said copolymers being in a range of 26 to 39 obtained by using the equation; ##EQU1## wherein BR is the butadiene component, the glass transition temperature being a single one below -50.degree. C. and lower than estimated glass transition temperature following Gordon-Taylor equation by 5.degree. to 10.degree. C. and a cured composition showing loss modulus of lower than 1.times.10.sup.-7 dyn/cm.sup.2 and a ratio of rolling resistance to wet grip being smaller than 0.82.

Abstract: A carcass rubber composition for tires comprising a polymer blend of diene synthetic elastomer and natural rubber. Said diene synthetic elastomer contains a solution polymerization star shaped SBR, preferably, in the ratio of 20-50 percent. 1, 2 structure in the butadiene unit is preferably less than 50 percent. The styrene content is preferably 10-20 percent.

Abstract: An automotive tire tread having a low rolling resistance including a cap tread rubber and a base tread rubber wherein the value of the loss tangent of the cap tread rubber is not more than 0.24 and the value of the resilience of the cap tread rubber is more than 60%. In addition, the value of the loss tangent of the base tread rubber should be less than that of the cap tread rubber.

Abstract: A rubber composition for a side wall of tires comprising a polymer blend of 20-100 parts by weight of solution polymerization star shaped SBR and 80-0 parts by weight of natural rubber and/or diene synthetic rubber. The glass transition temperature (Tg) of said star shaped SBR is preferably less than -50.degree. C. Styrene content in said star shaped SBR is preferably less than 20% parts by weight.

Abstract: A functional liquid for use as a heat transfer medium, anti-freezing liquid, insulating oil or the like, comprising at least one of dicyclopentylalkylbenzenes as the base.