consisting of c 1 20 hydrocarbyl radicals and q is from 3 to 50 in the aluminum activator preferably r 12 is a c 1 4 alkyl radical preferably a methyl radical and q is from 10 to 40 optionally a hindered phenol may be used in conjunction with the aluminoxane to provide a molar ratio of al hindered phenol from 2 1 to 5 1 if the hindered phenol is present generally the molar ratio of al hindered phenol if it is present is from 3 25 1 to 4 50 1 preferably the phenol is substituted in the 2 4 and 6 position by a c 2 6 alkyl radical desirably the hindered phenol is 2 6 di tert butyl 4 ethyl phenol the aluminum compounds aluminoxanes and optionally hindered phenol are typically used as activators in substantial molar excess compared to the total amount of metal in the catalysts e g group 4 transition metal in the phosphinimine catalyst aluminum total metal in the catalyst molar ratios may range from 10 1 to 10 000 1 preferably 10 1 to 500 1 most preferably from 50 1 to 150 1 especially from 90 1 to 120 1 typically the loading of the aluminoxane compound may range from 10 up to 60 weight preferably from 15 to 50 weight most preferably from 20 to 40 weight based on the weight of the calcined support impregnated with metal salt the aluminoxane is added to the support in the form of a hydrocarbyl solution typically at a 5 to 30 weight solution preferably an 8 to 12 weight solution most preferably a 9 to 10 weight solution suitable hydrocarbon solvents include.