Abstract: A process for the polymerisation of olefin monomers selected from (a) ethylene, (b) propylene (c) mixtures of ethylene and propylene and (d) mixtures of (a), (b) or (c) with one or more other alpha-olefins is performed in a polymerisation reactor in the presence of a supported polymerisation catalyst characterised in that prior to injection into the reactor said supported polymerisation catalyst in the form of a powder is contacted with an inert hydrocarbon liquid in a quantity sufficient to maintain said catalyst in powder form. The preferred inert hydrocarbon liquid is hexane. The supported polymerisation catalyst is preferably a supported metallocene catalyst. According to the process of the prescrit invention the level of fines associated with the polymer products is reduced in particular the level of fines having a diameter<125 ?m and microfines of diameter<50 ?m.

Abstract: A process for the polymerisation of olefin monomers selected from (a) ethylene, (b) propylene (c) mixtures of ethylene and propylene and (d) mixtures of (a), (b) or (c) with one or more other alpha-olefins is performed in a polymerisation reactor in the presence of a supported polymerisation catalyst characterised in that prior to injection into the reactor said supported polymerisation catalyst in the form of a powder is contacted with an inert hydrocarbon liquid in a quantity sufficient to maintain said catalyst in powder form. The preferred inert hydrocarbon liquid is hexane. The supported polymerisation catalyst is preferably a supported metallocene catalyst. According to the process of the prescrit invention the level of fines associated with the polymer products is reduced in particular the level of fines having a diameter<125 ?m and microfines of diameter<50 ?m.

Abstract: A novel process for the preparation of a supported transition metal catalyst system said method comprises the steps of: (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, and (iii) addition of a transition metal compound in a suitable solvent, characterised in that the molar ratio of organometallic compound (a) to ionic activator (b) in step (i) is in the range 0.1 to 2.0. By use of the reduced molar ratio of the organometallic compound to the ionic activator in step (i) better reproducibilty of the catalyst may be achieved as well as higher activities. In addition polymer properties may be improved for example higher melt strength resulting in better product performance. The preferred transition metal compounds are metallocenes.