SUPPORTED SINGLE-SITE CATALYSTS USEFUL FOR OLEFIN POLYMERIZATION.

摘要

A method for making supported single-site catalysts useful for olefin polymerization is disclosed. An organometallic complex that contains a nitrogen-functional heterocyclic ligand is first prepared and reacted with an alumoxane. This product is then combined, preferably with high-intensity mixing, with a slurry of inorganic support, followed by solvent removal to give a supported catalyst. By introducing the alumoxane at the right time during preparation, and by judicious selection and chemical treatment of the inorganic support, one can make catalysts with high activity and good ageing properties. The supported catalysts give olefin polymers with a favorable balance of physical properties, including low density, narrow molecular weight distribution, good melt-flow properties, and high bulk density.