| abstract |
The present invention is directed to rubbery polymers, such as polybutadiene rubber or styrene-butadiene rubber, that contain tin coupling agents and provide desirable dispersion of carbon black in rubber compounds, such as for use in tire treads. The tin coupling agents are defined by the general formulas (I) (X 3 Sn) 2 O or (II) (X 3 Sn)O-(CH 2 ) n -O(X 3 Sn), wherein X is a halogen and n is 1 to 20. A method of rubbery polymer synthesis, in one embodiment, involves mixing anionically polymerizable conjugated diene monomers with optional vinyl aromatic and an anionic-polymerization initiator, i.e., an organolithium compound, to form a mixture of living polymers. A tin coupling agent is added to the mixture of living polymers effecting polymerization conditions to form the tin coupled rubbery polymer. |