Process for the preparation of homopolymers and copolymers from propylene by means of a Ziegler-Natta catalyst system

摘要

The invention relates to the preparation of polymers from propylene by means of a Ziegler-Natta catalyst system comprising (1) a titanium component which contains titanium, magnesium, chlorine and a benzenecarboxylic acid derivative, (2) an aluminium component and (3) a silane component, characterised in that (1) is obtained by (1.1) first reacting (1.1.1) titanium tetrachloride, (1.1.2) an MgCl2-alcohol complex and (1.1.3) a phthalic acid derivative with one another under certain conditions, (1.2) then extracting the solid intermediate obtained from (1.1) with titanium tetrachloride until the solid which remains has become significantly higher in magnesium content, and (1.3) finally washing the solid remaining in (1.2) with an alkane.