摘要 |
A process for producing a conjugated diene polymer, characterized by polymerizing at least one conjugated diene with a catalyst consisting of (A) a reaction product of a Lewis base and a carboxylate of a rare earth element of the lanthanum series represented by Ln(R1CO2)3 wherein Ln is a rare earth element of the lanthanum series having an atomic number of 57 to 71 and R1 is a hydrocarbon substituent having 1 to 20 carbon atoms, (B) an organic aluminum compound represented by AlR2R3R4 wherein R2, R3 and R4, which may be identical or different, represent hydrogen atoms or hydrocarbon substituents having 1 to 8 carbon atoms, excluding the case where all of R2, R3 and R4 are hydrogen atoms at the same time, and (C) an (alkyl)aluminum halide represented by AlXnR53-n wherein X is Cl, Br, F or I; R5 is a hydrocarbon substituent having 1 to 8 carbon atoms; and n has a value of 1, 1.5, 2 or 3, or consisting of these (A), (B) and (C) components and (D) a conjugated diene. A polymer obtained by said process has a high cis-1,4-configuration content and is excellent in physical properties of vulcanizate.
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