KATALYTKOMPONENT FOER ZIEGLER-NATTA KATALYTER OCH FOERFARANDE FOER POLYMERISERING AV -OLEFINER

A catalyst component for use in unsupported Ziegler-Natta catalyst compositions for the polymerization of $g(a)-olefins having at least 3 carbon atoms. The catalyst component is obtained by treating an organomagnesium compound without chlorine with solid silane compounds containing one or two hydroxyl groups and then with titanium halide compounds. The treatment of organomagnesium compound is carried out by first treating with the solid silane compound in a temperature of 60-110C and thereafter with titanium halide compound optionally together with an electron donor compound. An unsupported catalyst composition, which comprises the above mentioned catalyst component together with a cocatalyst and optionally an external donor compound and a process for polymerization of $g(a)-olefins containing at least 3 carbon atoms with the use of the catalyst component are also claimed.