Abstract: A multilayer composite plastics material, containing at least one layer (A), which consists, to an extent of least 90 wt %, based on the total weight of this layer, of ethylene homopolymers or copolymers, at least one barrier layer (B), which substantially consists of polybutylene terephthalate, and also, if desired, layers of adhesion promoter (C) serving to improve the adhesion between these layers.

Abstract: A transition-metal catalyst component for a Ziegler catalyst system, obtainable by1) mixing an inorganic, oxidic carrier with a transition-metal starting component in an organic solvent,2) removing the solvent by evaporation,3) mixing the solid-phase intermediate from step (2) with3.1) an organoaluminum catalyst component of the formula AlR.sub.m X.sub.3-m, whereR is a C.sub.1 - to C.sub.18 -hydrocarbon radical,m is from 1 to 3, andX is OR, chlorine, bromine or hydrogen, and3.2) an organic carboxylate or an organosilicon compound or a mixture thereof in an organic solvent, and4) if desired, isolating the solid-phase intermediate by filtration, washing and drying,and the use thereof for the homopolymerization or copolymerization of ethene are described.

Abstract: A transition-metal catalyst component for a Ziegler catalyst system, obtainable by1) mixing, in a solvent, an inorganic, oxidic carrier with1.1) a vanadium trihalide/alcohol complex of the formula VY.sub.3 nZ-OH, whereY is chlorine or bromine,N is from 1 to 6, andZ is a monovalent, saturated, aliphatic or araliphatic hydrocarbon radical having not more than 10 carbon atoms, and1.2) a titanium trihalide or a titanium trihalide/aluminum trihalide complex, where the halogen can be chlorine and/or bromine, or a titanium trihalide complex of the formula TiY.sub.3. nZ-OH or a mixture thereof, whereY is chlorine or bromine,n is from 1 to 6, andZ is a monovalent, saturated, aliphatic or araliphatic hydrocarbon radical having not more than 10 carbon atoms or a mixture thereof, and1.3) a zirconium tetrahalide, where the halogen can be chlorine and/or bromine,2) removing the solvent by evaporation,3) mixing the solid-phase intermediate from step (2) with3.1) an organoaluminum catalyst component of the formula AlR.sub.

Abstract: A transition-metal catalyst component for a Ziegler catalyst system, obtainable by1) mixing, in a solvent, an inorganic, oxidic carrier with1.1) a vanadium trihalide alcohol complex of the formula VY.sub.3.nZ--OH, whereY is chlorine or bromine,n is from 1 to 6, andZ is a monovalent, saturated, aliphatic, aromatic or araliphatic hydrocarbon radical having not more than 10 carbon atoms, and1.2) a titanium halide or a titanium trihalide/aluminum trihalide complex, where the halogen can be chlorine and/or bromine, or a titanium trihalide complex of the formula TiY.sub.3.nZ--OH or mixtures thereof, whereY is chlorine or bromine,n is from 1 to 6, andZ is a monovalent, saturated, aliphatic, aromatic or araliphatic hydrocarbon radical having not more than 10 carbon atoms, and1.3) a compound of the formula BX.sub.n Y.sub.m R.sub.p or SiX.sub.n Y.sub.m R.sub.q or mixtures thereof, whereX is OR,Y is chlorine, bromine or hydrogen, andR is a C.sub.1 - to C.sub.