Process for producing propylene block copolymers

摘要

A propylene block copolymer having a high impact resistance is prepared without the generation of finely divided particles or the adhesion to the reactor, which propylene block copolymer having a weight ratio of 5/95-70/30 (process (1)/process (2)) is obtained by carrying out the particular polymerization processes (1) and (2) in this sequence under the action of the catalyst comprising the following A and B. A: particular transition metal compound. B: an alumoxane, the reaction product of an alkylboronic acid with an organoAl, a Lewis acid or ionic compound. Process (1): process for copolymerizing propylene and a specified comonomer in a ratio of 0/100-80/20. Process (2): process for producing a propylene polymer having a specified comonomer in an amount of 10% by weight or less.