CATALYST SYSTEMS FOR OLEFIN POLYMERIZATION BASED ON METALLOCENE COMPLEXES AND OLIGOALKYLALUMINATES WITH STERICALLY HINDERED ALKYL GROUPS AS COCATALYSTS

摘要

The invention relates to catalyst compositions for olefin polymerization comprising metallocene complexes and novel cocatalysts belonging to the group of oligoalkylaluminates with sterically hindered alkyl groups, such as a triphenylmethyl group. These cocatalysts are produced by two alternative synthetic methods, either by reacting methylalumoxane with a sterically hindered carbinol such as triphenyl carbinol; or in two-step processes comprising first reacting trimethylaluminum with said carbinol and then reacting the products of the first step with water. Catalyst systems containing these cocatalysts and metallocene complexes are active in polymerization and copolymerization reactions of ethylene and alpha-olefins.