FIELD: chemistry.
SUBSTANCE: present invention relates to a catalyst system based on at least a metallocene based on a rare-earth metal, having as a ligand a molecule consisting of two groups, selected from a group consisting of cyclopentadienyl groups substituted in at least 2 and 5 positions, substituted fluorenyl groups, an unsubstituted fluorenyl group and indenyl groups, substituted in at least 2 position, and which are connected by a bridge.
EFFECT: catalyst system enables to obtain copolymers of ethylene and 1,3-butadiene containing cyclic units having 6 carbon atoms, with the introduction of a butadiene monomer in the form of a trans-1,4-link in the copolymer, which is more than 50 mol % of vinyl (1,2), 1,4- and cyclic links.
21 cl, 5 ex, 5 tbl
