Process for the preparation of 1-olefin polymers
AssigneeHoechst Aktiengesellschaft
InventorsAndreas Winter, Walter Spaleck
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Abstract
In the case of Ziegler catalysts based on a metallocene as the transition metal component and an aluminoxane as the activator, preactivation of the metallocene with the aluminoxane results in a considerable increase in the activity of the catalyst system. Furthermore, 1-olefin polymers of a high degree of isotacticity and having compact, spherical particles, a very narrow particle size distribution and a high bulk density are obtained by means of a catalyst system of this type.
Claims7
In a process for the preparation of a 1-olefin polymer by polymerizing a 1-olefin of the formula R--CH.dbd.CH.sub.2 in which R is an alkyl group having 1 to 28 carbon atoms or copolymerizing these olefins together with ethylene at a temperature from -60.degree. to 200.degree. C., under a pressure of 0.5 to 60 bar, in solution, in suspension or in the gas phase and in the presence of a catalyst consisting essentially of a transition metal component containing metallocene and an aluminoxane of formulae IV or V as second component wherein the transition metal component has been preactivated in aluminoxane of the formula IV ##STR15## for the linear type and/or of the formula V ##STR16## for the cyclic type, R.sup.17 in the formulae IV and V being a C.sub.1 -C.sub.6 -alkyl group and p being an integer from 2 to 50, the process comprising
- a) dissolving the metallocene in a solution of aluminoxane in an inert hydrocarbon to form a preactivation solution;
- b) allowing the preactivation solution to stand for 5 minutes to 100 hours at a temperature of -78.degree. C. to 100.degree. C.;
- and
- c) stirring the alminoxane together with the liquid phase in the polymerization before the metallocene is added to the polymerization system.
Dependencies are inferred from the claim text.