PROCESS FOR POLYMERIZATION OR COPOLYMERIZATION OF ALPHA-OLEFINS USING MODIFIED ZIEGLER-NATTA CATALYST

摘要

The present invention relates to a process for the polymerisation or copolymerisation of alpha-olefins in the presence of a Ziegler-Natta catalyst system comprising on the one hand a catalyst solid comprising compounds of halogens, transition metals of Groups IV, V, VI of the Periodic Table of Elements, magnesium and optionally aluminum, free from a metal/carbon bond and on the other hand a catalyst consisting of organometallic compounds of metals of Group II or III of the said Table. This process is characterised in that before its use in polymerisation or copolymerisation, the catalyst solid is treated by water in a given quantity, this treatment making it possible to improve the conditions for obtaining polymers, particularly in a process of polymerisation or copolymerisation in the gas phase.