Catalyst system for producing polyethylene copolymers in a high temperature solution polymerization process

Abstract

Catalyst system for producing ethylene copolymers in a high temperature solution process, the catalyst system comprising (i) a metallocene complex of formula (I) wherein M is Hf X is a sigma ligand, L is a bridge of the formula —SiR—, wherein each Ris independently a C-C-hydrocarbyl, tri(C-C-alkyl)silyl, C-C-aryl, C-C-arylalkyl or C-C-alkylaryl n is 0, 1 or 2 Rand Rare the same or can be different and can be a linear or branched C-C-alkyl group, Rand Rare the same or are different and are a CH—Rgroup, with Rbeing H or linear or branched C-C-alkyl group Rand Rare the same or are different and can be H or a linear or branched C-C-alkyl group or a OR group, wherein R is a C-C-alkyl group Rand Rare the same or are different and can be H or a C(R)group, with Rbeing the same or different and Rcan be H or a linear or branched C-C-alkyl group or Rand Rand/or Rand Rtaken together form an unsubstituted 4-7 membered ring condensed to the benzene ring of the indenyl moiety, and Rand Rcan be the same or are different and can be H or a linear or branched C-C-alkyl group (ii) an aluminoxane cocatalyst and/or (iii) a boron containing cocatalyst and (iv) optionally an aluminum alkyl compound.