Hoechst Aktiengesellschaft

Ludwig B Ohm

Rainer Lecht

Werner Breuers

A particularly uniform Ziegler catalyst in the form of spherical particles is obtained by using shock waves instead of a stirrer for the thorough mixing of the reactants. By means of this highly active catalyst based on a magnesium dialkyl, it is possible to obtain polymers in the form of spherical particles in the polymerization of alpha-olefins. A further advantage of the catalyst according to the invention is its high activity, which is such that only very small amounts of the catalyst are required for the polymerization. The residual content of titanium and/or zirconium in the polymers prepared according to the invention is less than 10 ppm. By virtue of its good responsiveness to hydrogen, the catalyst is suitable for the preparation of polymers with a broad bimodal molar mass distribution, particularly in two-stage processes. The replacement of sulfur-containing electron donors such as diethyl sulfite with alcohols such as ethanol has the effect of reducing the odor nuisance and increasing the number of possible uses of the polymer. Considerable simplifications and advantages in handling, drying and processing are achieved as a result of the spherical shape of the particles and the very good flowability of the polymers and copolymers which is associated therewith.

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Hattersheim, Germany

Ludwig B Ohm