FIELD: chemistry.
SUBSTANCE: described is a catalytic composition for polymerising propylene or mixture of propylene with one or more copolymerisable comonomers, where the said catalytic composition contains one or more Ziegler-Natta procatalyst compositions, containing one or more compounds of transition metals and one or more monoesters; one or more cocatalysts, containing aluminium; and a mixture of two or more different selectivity controlling agents (SCA), where the said SCA mixture contains (i) 70 to 98 mol % of one or more esters of one or more aromatic monocarboxylic acids or their substituted derivatives and (ii) 30 to 2 mol % of one or more alkoxysilaned compounds, containing one or more 5-member cyclic groups, optionally containing one or more group 14, 15 or 16 heteroatoms. Described also is a method of polymerising propylene or mixture of propylene and one or more copolymerisable comonomers in the presence of the composition given above.
EFFECT: Ziegler-Natta catalytic composition with improved property of controlling rate of polymerisation and duration of the process, reduced formation of polymer agglomerates.
20 cl, 2 dwg, 2 tbl, 20 ex
