Supported metallocene catalyst system giving narrow molecular weight distribution in alkene polymerisation

摘要

Catalyst systems for the polymerisation of 2-12C alk-1-enes contain (a) an inorganic support (I), (b) metallocene complex(es) (II), (c) compound(s) (III) forming metallocenium ions, and optionally (d) organometallic compound(s) (IV) of alkali(ne earth) and/or group IIIB metal(s). (I) is an inorganic oxide with a pH of 1-6, which has pores and channels, the macroscopic volume fraction of which comprises 5-30% of the total particle. Also claimed are (i) preparation of alk-1-ene polymers using the catalyst systems; and (ii) the polymers per se. Polymerisation of 2-12C alk-1-enes, especially propylene or ethylene, is carried out at -50-300 deg C and 0.5-3000 bar, preferably in liquid monomers or in the gas phase. Prepolymerisation in suspension or in liquid monomers may be carried out first.