Process for the preparation of homopolymers of ethene and copolymers of ethene with higher alpha -monoolefins by means of a Ziegler catalyst system

The invention relates to the homopolymerization and copolymerization of ethene by means of a Ziegler catalyst system comprising (1) a transition-metal catalyst component, (2) an organoaluminium catalyst component and (3) optionally an organohalogen catalyst component, characterized in that (1) is the solid-phase product (VI) obtained by (1.1) first combining (1.1.1) an inorganic oxidic material (I) as support substance and (1.1.2) a solution (II) of (IIa) a certain oxahydrocarbon and (IIb) a mixture of (IIb1) a vanadium trichloride/alcohol complex, (IIb2) a titanium trihalide or titanium trihalide/alcohol complex and optionally (IIb3) a zirconium tetrahalide, with formation of a dispersion (III), evaporating the latter with formation of a solid-phase intermediate (IV), and (1.2) then (1.2.1) combining the intermediate (IV) from (1.1) and (1.2.2) a particular dissolved aluminium component (V) with formation of a dispersion, where the solid-phase product (VI) obtained as the dispersed material is the transition-metal catalyst component (1).