Polyolefins prepared with metallocene catalysts having 2-substituted indenyl type ligands

摘要

The novel metallocenes of the formula Iin which, preferably, M1 is Zr or Hf, R1 and R2 are alkyl or halogen, R3 and R4 are hydrogen, R5 and R6 are alkyl or haloalkyl, -(CR8R9)m-R7-(CR8R9)n- is a single- or multi-membered chain in which R7 may also be a (substituted) hetero atom, m+n is zero or 1, and R10 is hydrogen, form, together with aluminoxanes as cocatalysts, a very effective catalyst system for the preparation of polyolefins or high stereospecificity and high melting point. Polyolefins with unique or improved properties are obtained by polymerizing an olefin in the presence of a metallocene combined with a cocatalyst, wherein the metallocene is preferably a zirconocene or a hafnocene, and the Zr or Hf central atom is coordinated with two ligands which are derivatives of 2-substituted indenyl nuclei and which are substituted with at least one and up to four groups (e.g. aliphatic or aromatic groups) on the six-member rings of the indenyl nuclei. The indenyl nuclei are optionally substituted at the 3-position and are joined by a 1,1'-bridge of the formula -(CR8R9)m-R7-(CR8R9)n-, which is a single- or multi-membered chain in which R7 can also be a (substituted) hetero atom, m and n are identical or different and are zero, 1, or 2, and m+n is zero, 1, or 2.