CATALYTIC POLYMERISATION OF OLEFINS

1. A process for the preparation of homopolymers and copolymers of C2 -alpha-monoolefins, at from 20 to 160 degrees C, under a pressure of from 1 to 100 bar, by means of a Ziegler-Natta catalyst system comprising (1) a titanium-III component, in the preparation of which (1.1) a titanium-containing compound (a) of the formula TiCl3 .nAlCl3 , where n is a number from 0.01 to 1, and (1.2) an ester (b), which contains a total of from 2 to 34 carbon atoms and has the formula R**1 -O-CO-R**2 or see diagramm : EP0041139,P12,F2 where R**1 is (I) alkyl of 1 to 16 carbon atoms or (II) phenylalkyl of a total of 7 to 23 carbon atoms, in which up to 5 hydrogen atoms of the phenyl radical can be substituted by alkyl of 1 to 4 carbon atoms, and R**2 is (I) hydrogen, (II) alkyl of 1 to 18 carbon atoms, (III) phenylalkyl of a total of 7 to 23 carbon atoms, in which up to 5 hydrogen atoms of the phenyl radical can be substituted by alkyl having 1 to 4 carbon atoms, (IV) phenyl or (V) alkylphenyl of a total of 7 to 23 carbon atoms, in which up to 5 hydrogen atoms of the phenyl radical can be substituted by alkyl of 1 to 4 carbon atoms, are subjected to a milling treatment, wherein (A) a vibratory ball mill having a milling acceleration of from 30 to 80 m . sec**-2 is used, (B) the mill is first charged with the titanium-containing compound (a) and - if desired - is run at from -50 to +100 degrees C for a period of from 0.5 to 100 hours in the absence of a diluent, thereafter (C) the amount of the ester (b) which corresponds to a molar ratio of titanium in the titanium-containing compound (a) : ester (b) of from 1:1.5 to 1:0.01 is added at a rate of 0.01-200 ml/min per 2.5 kg of titanium-containing compound (a), continuously or in small portions, and in the absence of a diluent, whilst milling the mixture at from -50 to +80 degrees C, thereupon (D) the material is kept for a period of from 1 to 120 hours at from +15 to +100 degrees C whilst being milled, following this (E) - if desired - the product obtained from (D) is milled further for a period of from 0.5 to 60 minutes at from -50 to +5 degrees C in the absence of a diluent, then (F) - if desired, and advantageously - the product obtained from (D) or (E) is kept for a period of from 0.25 to 300 hours at from +20 to +150 degrees C without being milled, and thereafter (G) - if desired - the product obtained from (F) is milled again, for a period of from 0.5 to 60 minutes, at from -50 to +5% C, in the absence of a diluent, (