CATALYST FOR THE POLYMERIZATION OF OLEFINS

摘要

The present invention relates to catalysts systems for the polymerization of ethylene and its mixtures with olefins CH2=CHR, wherein R is an alkyl, cycloalkyl or aryl radical having 1-12 carbon atoms, comprising (A) a solid catalyst component comprising Ti, Mg, halogen, and optionally an electron donor compound in a donor/Ti molar ratio lower than 1, (B) an aluminum alkyl compound and (C) a silicon compound of formula RImSi(ORII)n in which RI is C1 -C20 alkyl group, RII is a secondary or tertiary alkyl group or a cycloalkyl having from 3 to 20 carbon atoms, m is an integer ranging from 0 to 3, and n is (4-m). The catalyst of the invention is suitably used in (co)polymerization processes of ethylene to prepare (co)polymers having narrow Molecular Weight Distribution (MWD) and high activity.