CATALYST COMPOSITION

摘要

A catalyst composition for use in the polymerization of a conjugated diene or the copolymerization of a conjugated diene with an aromatic vinyl compound, which comprises (A) a metallocene-type complex of a rare earth metal compound (a samarium complex, etc.) and (B) an ionic compound comprising a non-coordinating anion and a non-coordinating cation (triphenylcarbonium tetrakis(pentafluorophenyl)borate, etc.) and/or an aluminoxane. The catalyst is useful for producing a polymer which has a microstructure having a high cis-1,4 structure content and has a narrow molecular-weight distribution.