| abstract |
The present invention relates to the field of olefin polymerization catalysts, in particular, to a catalyst system for olefin polymerization, a prepolymerized catalyst composition for olefin polymerization, and their application in olefin polymerization. The catalyst system contains: a solid catalyst component, the solid catalyst component contains a titanium compound, a magnesium compound and an internal electron donor; an alkyl aluminum compound; and an external electron donor; the internal electron donor contains an aromatic carboxylate compound, The external electron donor contains the mixture of the lactone compound shown in formula I and the silane compound, the present invention adopts the lactone compound and the silane compound as the external electron donor, the alkyl aluminum as the cocatalyst, and the aromatic carboxyl compound. The acid ester compound is used in conjunction with the solid catalyst component of the internal electron donor. When this catalyst system is used for olefin polymerization, it not only has high catalytic stereospecificity, but also has good hydrogen adjustment sensitivity and improved copolymerization ability. |