Production of a new type of butadiene polymer

1,139,431. Stereoblock polybutadienes. BADISCHE ANILIN- & SODA-FABRIK A.G. 13 May, 1966 [15 May, 1965], No. 21258/66. Heading C3P. Stereoblock polymers of butadiene are made by reacting (1) a catalyst containing hydrocarbon solution of uncrosslinked polybutadiene made by polymerizing butadiene with a catalyst comprising a compound of a transition metal of Groups IV to VIII of the Mendeleeff Periodic System and an alkyl metal compound until the polymer has a K-value of from 20 to 80, with (a) a similar solution of uncrosslinked polybutadiene of different configuration, until the resulting polymer has a K-value of 90 to 120. At least one of the solutions may contain unreacted butadiene. The solutions (1) and (2) are preferably effected below 0‹ C., and the reaction between - 5‹ and + 30‹ C. The specification contains numerous examples of catalysts which give rise to polybutadienes of different and opposite configurations. The polymers may be vulcanized.