Process for preparing a Ziegler-Natta catalyst

摘要

The present invention relates to a process for preparation of a catalyst of Ziegler-Natta type comprising a refractory oxide support. The process comprises the following stages: (a) and (b) contacting the support in the course of two separate stages with a dialkylmagnesium and with an organoaluminium compound in any order, (c) contacting the product resulting from (a) and (b) with an organic halogen compound, and (d) contacting the solid resulting from (c) with at least one tetravalent titanium compound. The invention also relates to an olefin polymerization process using the catalyst. The resulting polymers have an improved bulk density.