CYCLIC ORGANOSILICON COMPOUNDS AS ELECTRON DONORS IN ZEIGLER-NATTA CATALYST SYSTEMS FOR PRODUCING PROPYLENE POLYMER HAVING HIGH MELT-FLOWABILITY

摘要

PROBLEM TO BE SOLVED: To provide novel cyclic organosilicon compounds, and a method for using the same as a component of catalysts for olefins polymerization.SOLUTION: The cyclic organosilicon compounds having a structure represented by the following general formula and a method for using the compounds as a component of catalysts for producing propylene polymer having a very high melt-flowability are disclosed. The cyclic organosilicon compounds are employed as external electron donors in Ziegler-Natta catalyst systems to dramatically improve the hydrogen response, and therefore the catalyst systems can be used to prepare a polymer having high melt-flowability and high isotacticity at high yield.