MANUFACTURE OF PROPENE MONOPOLYMER AND COPOLYMER BY ZIEGLER-NATTA CATALYST SYSTEM

Polymers of propylene are prepared by means of a Ziegler-Natta catalyst system comprising (1) a titanium component based on a finely divided, shaping silica gel and containing a benzenecarboxylic acid derivative in addition to titanium, magnesium and chlorine, (2) an aluminium component and (3) a silane component, characterised in that a titanium component (1) is used which is obtained by (1.1) first (I) preparing a support from (Ia) a silica gel, (Ib) an organomagnesium compound and (Ic) a gaseous chlorinating agent by (1.1.1) first reacting (Ia) with (Ib), (1.1.2) then passing (Ic) into the product from (1.1.1) and isolating (I), (1.2) then preparing a solid-phase intermediate from (I), (II) an alkanol, (III) titanium tetrachloride and (IV) a phthalic acid derivative by (1.2.1) first reacting (I) with (II), (1.2.2) subsequently introducing (III) into the product from (1.2.1), with the proviso that (IV) is also introduced during (1.2.1) and/or (1.2.2), (1.3) then extracting the solid-phase product from (1.2) with titanium tetrachloride, and (1.4) finally washing the solid-phase product from (1.3) with a liquid hydrocarbon.