| 摘要 |
A process for polymerizing one or more (alpha)-olefins of up to 10 carbon atoms which comprises contacting the one or more (alpha)-olefin under polymerization conditions with a catalyst system comprising: (a) a titanium halide-containing magnesium, titanium, halide and polycarboxylic acid containing a pro-catalyst component wherein the component is obtained by contacting a magnesium compound of the formula MgR'R", wherein R' and R" are, independently, alkoxide group, aryloxide group or halogen, with a halogenated tetravalent titanium compound in the presence of a halohydrocarbon and a polycarboxylic acid ester electron donor, (b) an organo-aluminum cocatalyst component, and (c) an organosilane selectivity control agent represented by general formula (I), wherein R1 and R2 are, independently, alkyl groups containing from 1 to 12 carbon atoms; aryl groups containing from 1 to 12 carbon atoms, alkaryl groups containing from 1 to 12 carbon atoms, aralkyl groups containing from 1 to 12 carbon atoms, hydrocarbyloxy groups containing 1 to 12 carbon atoms or halogen; and R3 and R4 are hydrocarbyloxy groups containing from 2 to 12 carbon atoms. The process affords high catalyst productivity and produces polymer products having improved polymer properties such as broad molecular weight distribution, and high stiffness while retaining low oligomer content. |
