Abstract: A process is provided for making improved rubbery vulcanizates wherein rubbery polymer is mixed with silica or silica and carbon black, polyfunctional polysulphide silane compound and sulphur-based vulcanizaiton agents and the mixture is vulcanized, the rubber polymer is a polymer having two or three domains or a mixture of a polymer having two or three domains and one of polybutadiene, styrene-butadiene polymer or natural rubber or a mixture of polybutadiene and natural rubber.

Abstract: Rubber compositions for use in tire tread compounds comprise co-vulcanizable blends of high 1,2 (vinyl) content polybutadiene of high molecular weight and high cis-1,4-poly-butadiene of high molecular weight. The blends show a high degree of homogeneity, so that they act effectively as a single polymer, and exhibit a substantial absence of a glass transition temperature. Both of the polymers in the composition should have a relatively high weight average molecular weight. The relative amounts of the two polymers are such as to obtain a 1,2-group content in the blend of from 35-65 percent (i.e. from 35-65 percent of the polymer units are in the 1,2-configuration). The blend may be compounded with conventional compounding ingredients for curing purposes, and optionally with additional polymers as natural rubber and/or SBR. The vulcanizates of the compositions exhibit a superior and unexpected balance of resilience, traction and wear properties.

Abstract: Elastomeric compositions containing EPDM elastomers are provided, the vulcanizates of which show substantially improved adhesion properties with good dynamic ozone resistance, superior aged fatigue life and high resilience. The EPDM used is of high molecular weight and has a non-conjugated diene content of at least 6 weight percent preferably at least 7.5%. The composition also contains highly unsaturated elastomers, such as natural rubber and polybutadiene, as the additional elastomeric components.