POLYPROPYLENE FORMING CATALYSTS

摘要

Catalysts for the polymerization of alpha-olefins which comprise the reaction product of: a) an Al-alkyl compound; b) a silicon compound containing at least one Si-OR or Si-OCOR or Si-NR2 bond, R being a hydrocarbyl radical; c) a solid comprising as essential support, a Mg dihalide in active form and supported therein a Ti halide or a halo-Ti-alcoholate and a particular type of electron donor compound.