Polymerisation catalysts
OwnerRichard Henry Weatherheadinventor
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Abstract
A catalyst system suitable for preparing substantially terminally unsaturated atactic polymers or copolymers of α-olefins having a number average molecular weight in the range 300-500,000 comprises: A) a metallocene complex; and B) a cocatalyst comprising: i) an aluminoxane; and ii) a Group III metal alkyl compound having at least 2 carbon atoms. The use of the Group III metal compound allows for a reduction in the aluminoxane content in the cocatalyst. Preferred metallocenes are those having alkyl substitution on the cyclopentadienyl rings and the preferred Group III metal alkyl compound is triisobutyl aluminum.
Claims17
A catalyst system suitable for use in the preparation of substantially terminally unsaturated atactic polymers or copolymers of α-olefins having a number average molecular weight in the range 300-500,000 said catalyst system comprising
- (A) a metallocene of formula:
- [RmCpH(5-m)][RnCpH(5-n)]M(Z)Y
- wherein
- CpH is a cyclopentadienyl ligand,
- each R represents an alkyl or an aryl substituent on the CpH ligand or two R's may be joined together to form a ring, or the Rs in each Cp group when taken together represents an Si or C bridging group linking two CpH groups wherein said Si or C group may itself be substituted by hydrogen atoms or C1-C3 alkyl groups,
- M is a metal selected from hafnium, zirconium and titanium,
- Z and Y are selected from hydrogen, halide, a trifluoromethane sulphonate, a 1,3-diketone, a β-ketoester, an alkyl or an aryl group and may be the same or different,
- each of m and n is the same or different and has a value of 0 to 5, and
- (B) a cocatalyst comprising (i) an aluminoxane and (ii) a Group III metal alkyl compound having at least 2 carbon atoms.
Dependencies are inferred from the claim text.