Bp Chemicals Limited

Ineos Europe Limited

Michael John Taylor

Sergio Mastroianni

Brian Stephen Kimberley

Grant Berent Jacobsen

Christel Marie-Claude Mealares

Ian M Munro

An improved method for the preparation of a supported polymerisation catalyst system comprises the combination of (i) a porous support (ii) a polymerisable monomer, (iii) a polymerisation catalyst, and (iv) a cocatalyst, characterised in that the polymerisable monomer is added to the porous support before addition of one or both of the polymerisation catalyst and the cocatalyst. The preferred polymerisation catalyst is a metallocene complex and the preferred porous support is silica. The resultant supported catalysts are stable over long periods of time. The supported catalyst are particularly suitable for use in the gas phase.

Supported polymerisation catalysts

A method for the preparation of a supported transition metal catalyst system which includes the steps of: (i) mixing together in a suitable solvent (a) an aluminoxane and (b) an ionic activator containing a cation and an anion, wherein the anion has at least one substituent containing a moiety having an active hydrogen, (ii) addition of the mixture from step (i) to a support material, and (iii) addition of a transition metal compound in a suitable solvent. The use of tetraisobutylaluminoxane as the aluminoxane results in a more stable activity profile and improved polymer properties in particular melt strength.

Supported ionic metallocene catalyst systems may be prepared by a method comprising the following steps: i) mixing together in a suitable solvent: a) an organometallic compound, and b) an ionic activator comprising a cation and an anion; ii) addition of the mixture from step (i) to a support material; iii) addition of a metallocene complex in a suitable solvent; iv) further addition of an organometallic compound in a suitable solvent; and v) removal of the solvent. The preferred supported catalysts comprise a constrained geometry metallocene complex for example (t-butylamido)(tetramethyl-&rarr; -cyclopentadienyl) dimethyl silanetitanium-&rarr; -1,3-pentadiene and are particularly suitable for the polymerisation of ethylene or the copolymerisation of ethylene and &agr;-olefins having from 3 to 10 carbons in the gas phase. The supported metallocene catalysts of the present invention show improved productivity compared to supported ionic metallocene catalyst systems of the prior art particularly when used in the gas phase.

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Middlesex, United Kingdom

Michael John Taylor