Process for obtaining a catalytic system for the polymerization of alpha-olefins in suspension, in gas phase at low and high temperature or in a mass at high pressure and high or low temperature

摘要

These catalytic systems are particularly suitable for the polymerization of alpha -olefins containing from 2 to 20 carbon atoms, as well as for the copolymerization of ethylene with alpha -olefins containing from 3 to 20 carbon atoms, diene and cycloalkenes. The catalysts can be used in processes wherein the catalyst is suspended in a solvent, in processes in gas phase as well as in mass polymerization processes at high temperatures and pressures. The catalytic system is characterized by the mixture of two components A and B. The component A (catalyst) is formed by a properly functionalized inorganic porous oxide, by organo aluminium compound and by an organometallic compound of a metal of the groups 3, 4, 5 and 6 of the periodic table. The functionalization of the inorganic oxide consists in the introduction of functional groups to be used to strongly fix the organoaluminium compound and the organometallic compund. The component B or co-catalyst which is used for the activation of the catalyst is composed of organoaluminium compounds, perfluorinated derivatives of boron or a mixture thereof. The catalytic system prepared according to the present invention, have the advantage of strongly fixing the active components to the inorganic support, thus avoiding their migration in the polymerization medium. In this way a good control of the morphology of the distribution of the particle sizes and of the molecular weight of the obtained polymers is reached. Moreover these catalytic systems show a high activity in the polymerization reaction, high ratios between catalyst-co-catalyst being unnecessary, since polymers with low contamination levels are obtained.