Catalyst component comprising magnesium, titanium, a halogen and an electron donor, its preparation and use

摘要

Process for preparing an olefin polymerisation catalyst component comprising magnesium halide, titanium halide and a carboxylic acid ester electron donor, in which the precursors of its constituents are reacted in solution from which the component is eventually precipitated, this precipitation being accompanied by co-precipitation of one or more oligoesters of the carboxylic acid formed in a controlled manner. The component is employed, together with an organometallic co-catalyst, for polymerisation of C2-C10 alpha -olefins.