PURPOSE: To obtain the titled polymer having a high elasticity at a low cost with catalysts of no toxicity and corrosiveness, by polymerizing 1,3-butadiene in a solvent containing halogen in the presence of a specific cis-1,4-polymerization catalyst, and then in the presence of a 1,2-syndiotactic polymerization catalyst in two stages.
CONSTITUTION: 1,3-Butadiene is polymerized in a halogenated hydrocarbon, e.g. methylene chloride, in the presence of a cis-1,4-polymerization catalyst consisting of (A) a cobalt compound, e.g. cobalt octoate, (B) an organoaluminum compound, e.g. triethylaluminum, expressed by the formula AlR3 (R is alkyl) and (C) water in an amount of 0.25W1.5mol/mol the component (B) in the first stage and then in the presence of a 1,2-syndiotactic polymerization catalyst containing at least the components (A) and (B) in the second stage to give the aimed polymer.
GOTOU KOUHEI
SHIMOZATO YASUYUKI
SEKINE KAZUO
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