| abstract |
PROBLEM TO BE SOLVED: To provide an efficient method for producing a coupling type butadiene polymer having a high 1,4-cis content and a coupling type conjugated diene polymer. SOLUTION: (I) A cis-bond unit in a butadiene unit is 50% or more, and a number average molecular weight (Mn) is 1,000 to 1. Butadiene-based polymer of 0,000,000 (II) A coupling type polymer comprising 100 to 10 parts by weight of a polymer to which at least two molecules of the polymer (I) are coupled. After polymerizing a conjugated diene monomer in the presence of a catalyst in which a group IV transition metal compound having a cyclopentadienyl skeleton and a cocatalyst are brought into contact with each other under conditions satisfying the following two formulas: , Contact with a terminal modifier. -100 <T <80 0.017 <t <6000exp (-0.0921T) t: Contact time (min), T: Contact temperature (° C). |