Catalyst systems for the polymerization of C¶2¶-bis C¶1¶¶0¶-alk-1-enes

Catalyst systems for polymerising C2 to C10-alk-1-enes contain as active components (a) a metallocene complex having the general formula (I), in which the substituents and indexes have the following meaning: M stands for a metal of the secondary group III, IV or V of the periodic table or for a metal from the group of the lanthanides; X stand for halogen, hydrogen, C1- to C10-alkyl, C3- to C10-cycloalkyl, C6- to C15-aryl, alkylaryl with 7 to 15 C atoms or -OR , in which R stands for C1 to C1 to C10-alkyl, C6- to C15-aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroalkyl or fluoroaryl having each 1 to 10 C atoms in the alkyl residue and 6 to 20 C atoms in the aryl residue; n stands for the valency of M, less the number two; R to R stand for hydrogen, C1 to C10-alkyl, C3- to C10-cycloalkyl, which in turn can carry a C1- to C10-alkyl as substituent, C6- to C15-aryl or arylalkyl, whereas if required two adjacent residues may also stand together for cyclic groups having 4 to 15 C atoms, or Si(R )3, in which R stands for C1- to C10-alkyl, C6- to C15-aryl or C3- to C10-cycloalkyl; y , y stand for CH2, C(R )2, Si(R )2, Ge(R )2 or Sn(R )2, in which R stands for C1- to C10-alkyl, C6- to C15-aryl, C3- to C10-cycloalkyl, alkylaryl or Si(R )3, in which R stands for C1- to C10-alkyl, C6- to C15-aryl, C3- to C10-cycloalkyl or alkylaryl; as well as (b) an open-chain or cyclic alumoxane compound having the general formula (II) or (III), in which R stands for a C1- to C4-alkyl group and m is an integer between 5 and 30.