Powder catalyst composition and process for polymerizing olefins with the use thereof

摘要

The present invention provides a powder catalyst composition for producing by gas-phase polymerization olefin polymers having excellent polymer qualities and good particle properties in a high yield. The powder catalyst composition comprises fine particles of the following Component (B) coated with the following Component (A), and is characterized in that the ratio of the Component (A) to the Component (B) based on percent by weight ranges from 5:50 to 95:50: Component (A): an inorganic compound in the form of fine particles having an average particle diameter of 0,003-1 mu m and mainly comprising an inorganic oxide, and Component (B): a solution or dispersion in a hydrocarbon of the following Sub-components (i) and (ii): Sub-component (i): a compound of a transition metal belonging to the IVB group of the Periodic Table, and Sub-component (ii): an alumoxane, a Lewis acid, or an ionic compound which can convert the Sub-component (i) upon reaction therewith into a cation. A process for polymerizing an olefin with use of the composition is also disclosed.