Borealis Technology Oy

Borealis A/s

Klaus-Joachim Jens

Richard Blom

Ivar Martin Dahl

Arild Follestad

Svein Staal Eggen

Mats Tilset

Mark H Voges

Morten Fr&oslash;seth

A catalyst system for the polymerization of ethylene, comprising a particulate inorganic oxide supporting a chromium oxide being in a reduced oxidation state and a metallocene compound having the formula Cp ZrR&prime;R&Prime;, wherein each Cp, being equal or different, is an unsubstituted or substituted cyclopentadienyl compound, and R&prime; and R&prime;, independent of each other, are selected from the group comprising alkyls having 1 to 6 carbon atoms, unsubstituted or substituted benzyl, and phenoxy substituted with alkyls having 1 to 6 carbon atoms; or R&prime; or R&Prime; may be a halide. The catalyst system is prepared by a method comprising the steps of calcining the support, joining onto the surface of the support a chronium-organic compound, subjecting the obtained catalyst precursor to oxidizing conditions to obtain the chromium in an oxidized state, reducing the oxidized chromium to obtain a main part thereof in a bivalent oxidation state, and contacting the reduced catalyst with the metallocene compound.

Catalyst system for ethylene polymerizations

The invention relates to the use of cyclic carbene-&eegr;-ligand complexes for catalysis of olefin polymerization.

Catalyst for the polymerization of olefins

A process for the polymerization of ethylene and optionally &agr;-olefins to form ethylene homopolymer or copolymers having a broad molecular weight distribution, comprising polymerization of 100-80 wt. % of ethylene and 0-20 wt. % of comonomer in the presence of two independent, simultaneously present catalysts A and B, wherein catalyst A, deposited on an inorganic support, comprises chromium in a predominantly oxidant state of 2 and catalyst B comprises a bis-cyclopentadienyl chromium compound reacted with an inorganic support.

Process for producing polyethylenes having a broad molecular weight distribution, and a catalyst system used thereby

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Langesund, Norway

Klaus-Joachim Jens