Method for polymerizing conjugated diolefins (dienes) with catalysts based on cobalt compounds in the presence of vinylaromatic solvents

A process for the polymerisation of conjugated diolefins comprising polymerizing conjugated diolefins in the presence of,

• catalysts consisting of,
• (a) cobalt compounds,
• (b) organoaluminum compounds, and
• (c) modifiers comprising at least one Lewis base which contains as a donor atom at least one element selected from Groups Vb and VIb of the periodic system of the elements,
• as well as in the presence of vinyl aromatic compounds,
• wherein the polymerization is performed at temperatures of −30° C. to +80° C.;
• the molar ratio of components (a):(b):(c) is in the range from 1:10-1000:0.1-100;
• the quantity of component (a) of the catalyst used is 1 μmol. to 10 mmol., relative to 100 g of the monomers used;
• and the quantity of vinyl aromatic compounds is 10 g to 2000 g, relative to 100 g of the monomers used.