| abstract |
The present invention is directed to an amine containing catalyst system for synthesizing rubbery polymers, such as polybutadiene rubber and styrene-butadiene rubber, having a high trans microstructure. The catalyst system, in one embodiment, includes (a) an organolithium compound, (b) a group IIa metal salt, (c) an organoaluminum compound, and (d) an amine compound which can be selected from (1) a heterocyclic aromatic compound which includes a ring structure with one or more nitrogen atoms as part of the ring; (2) a heterocyclic non-aromatic compound which includes a ring structure with two or more nitrogen atoms as part of the ring; (3) an aromatic compound including a ring structure substituted with at least one amine and at least one polar functionality containing group selected from a carboxyl group or a hydroxyl group; (4) a bicyclic chelating diamine compound; or (5) an aliphatic amine which includes a C 5 -C 20 alkyl group. |