Patent ID: 6147024
Filing Date: 2000-11-14
Classification: C08F,Y02P

Abstract:
A catalyst system for the polymerization and copolymerization of olefins comprising:(a) a conventional Ziegler-Natta catalyst component comprising a solid catalyst component obtained by (i) suspending a dialkoxy magnesium in an aromatic hydrocarbon that is liquid at normal temperatures, (ii) contacting the dialkoxy magnesium with a titanium halide and further (iii) contacting the resulting composition a second time with the titanium halide, and contacting the dialkoxy magnesium with a diester of an aromatic dicarboxylic acid at some point during the treatment with the titanium halide in (ii);(b) a mixture of two electron donors wherein one electron donor is diisopropyldimethoxysilane, di-t-butyldimethoxysilane or dicyclopentyldimethoxysilane and the other electron donor is cyclohexylmethyldimethoxysilane in a molar ratio of from about 1:3 to about 3:1 of the second to the first; and(c) triethylaluminum as a co-catalyst, wherein the Si/Ti molar ratio is about 2.