A PROCESS FOR THE PREPARATION OF AN ETHYLENE COPOLYMER

摘要

The invention relates to a process for the preparation of an ethylene copolymer by polymerizing ethylene and at least one alpha-olefin in the presence of a chromium-containing catalyst and a diluent. In the first step of the polymerization ethylene and/or propylene and optionally at least one alpha-olefin comprising 3 to 12 carbon atoms are polymerized with a chromium containing catalyst in an inert diluent in the absence of an alkyl-containing promoter and in a second step, after 2-650 grams of polymer per gram of catalyst have been produced in the first step, the polymerization of ethylene and alpha-olefin takes place in the presence of an alkyl-containing promoter.