Manufacture of poly (.alpha.-olefins)

Abstract

A process for the manufacture of poly(.alpha.-olefins) by polymerization of .alpha.-olefins using a catalyst system comprising (1) a titanium-containing component of (1.1) a substance of the formula TiCl.sub.3 . 1/3 AlCl.sub.3 and (1.2) an organic electron donor containing phosphorus atoms and/or nitrogen atoms, ground together with said substance (1.1), and (2) an aluminum-containing component of a substance of formula Al(C.sub.n H.sub.2 ..sub.n.sub.+1).sub.3 or Al(C.sub.n H.sub.2..sub.n.sub.+1).sub.2 Cl, where n is an integer of from 2 to 6. The characteristic feature is that the catalyst system used is one in which the component (1.1) has been ground with component (1.2) without the use of auxiliaries or additives in a vibratory ball mill using specific steel balls and a specific grinding acceleration over a specific period of time at a temperature which is just below that at which the particles in the ground material begin to agglomerate. The advantage of this process is that the efficiency of the catalyst system is very high and/or poly(.alpha.-olefins) are obtained which have a particularly large fraction which is insoluble in boiling n-heptane.