Patent ID: 7271226

Claim:
A process for the polymerisation of olefin monomers, comprising polymerising an olefin monomer selected from the group consisting of (a) ethylene, (b) propylene, (c) mixtures of ethylene and propylene, and (d) mixtures of (a), (b), or (c) with one or more other alpha-olefins in a polymerisation reactor in the presence of a catalyst system including (a) a polymerisation catalyst, (b) an ionic activator having a cation and an anion, wherein the anion has at least one substituent comprising a moiety having an active hydrogen, and (c) an organometallic compound of a Group IIIB metal having at least one unit of formula: M—O—R or M—O—M where M is the Group IIIB metal and R is a hydrocarbyl group, wherein an activated catalyst component including the polymerisation catalyst (a) and the ionic activator (b) is first prepared, dried and then the organometallic compound (c) is premixed with said dried activated catalyst component as a separate component before the resulting mixture is added to the reactor as the catalyst system.