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AssigneeBP Chemicals Limited
InventorsJean-Claude Bailly, Philippe Bres, Christine Chabrand, Erick Daire
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The present invention relates to a solid catalyst suitable for polymerizing olefins in a heterogeneous process, the catalyst consisting of spheroidal particles having a narrow particle size distribution and comprising (i) a support containing magnesium dichloride and an electron-donor free from labile hydrogen, (ii) a zirconium metallocene, and (iii) optionally an organoaluminium compound which is an aluminoxane preferably. The solid catalyst may be used in the form of a prepolymer comprising a polyethylene or a copolymer of ethylene and an active zirconium metallocene catalyst essentially consisting of atoms of Zr, Mg, Cl and Al, preferably in the form of spheriodal particles. The solid catalyst or the prepolymer may be used for producing polyethylene or copolymer of ethylene having from 0.5 to 20 ppm of zr and a molecular weight distribution from 2 to 5, in the form of a powder having a bulk density from 0.3 to 0.55 g/cm.sup.3, preferably consisting of spheroidal particles.
Solid catalyst suitable for a heterogeneous process for polymerizing one or more olefins, the solid catalyst consisting of spheroidal particles having a mass-average diameter, Dm, of 10 to 100 microns and a particle size distribution such that the ratio of Dm to the number-average diameter Dn, of the particles is not higher than 3, catalyst comprising:
Prepolymer particles comprising (i) polyethylene or copolymer of ethylene with up to 10% by weight of at least one C3 to C8 alpha-olefin and (ii) and active catalyst for a further (co-) polymerization of olefins, said catalyst essentially based on a zirconium metallocene and containing atoms of zirconium, magnesium, chlorine and aluminum, in a quantity such that the prepolymer contains from 1.0 to 500 g of polyethylene or copolymer of ethylene per millimole of zirconium and the atomic ratio Al/Zr is from 10 to 1000.
Dependencies are inferred from the claim text.