Abstract: The invention relates to a process for the preparation of a polymer from ethylene, an .alpha.-olefine and optionally a diene, according to which these monomers are polymerized under the influence of a metallocene catalyst, the polymerization taking place in the presence of a catalyst comprising a specific 2-indenyl metallocene, resulting in a bimodal, elastomeric polymer with a molecular weight distribution of more than 3.5, under such reaction conditions that the amount of water in the polymerization medium is smaller than 0.5 ppm.The invention also relates to polymers with a specific branching index.

Abstract: The present invention relates to a catalyst and a process for the preparation of an olefin polymer, which catalyst comprises a transition metal component and an organometal component. The transition metal component comprises a transition metal atom onto which an imidoaryl ligand is bound.More specifically the transition metal is vanadium or titanium.

Abstract: A process is disclosed for preparing a titanium catalyst component useful for homopolymerizing 1-alkenes and for copolymerizing 1-alkenes with each other and/or with ethylene, consisting essentially in grinding a titanium halide compound/electron-donor complex with a magnesium aluminum halide obtained by precipitation from an organic solvent.In the process the ground product is first washed with a washing liquid containing a solvent for the aluminum halide/electron-donor complex which forms during the grinding process and by preference at least one alcohol, the molar ratio between alcohol and titanium in the ground product ranging between 50:1 and 1:20, and then the washed product is exposed to a liquid titanium halide compound.With this procedure, it is possible to obtain a titanium component which imparts to the polymerization catalyst an excellent stereospecificity along with a very high activity, and with which it is possible to obtain polymers, e.g.