| abstract |
The invention provides a process for producingnpolypropylene and/or random copolymers of propylene type usingna stereoregular catalyst which comprises a titanium-containingnsolid catalyst component (A), an organoaluminumncompound (B) and if required an organosilicon compound (C),nwhereinn [I] before carrying out homopolymerization of propylene ornrandom copolymerization of propylene with an α-olefin other.nthan propylene, the above component (A), an organoaluminumncompound (B') and if required an organosilicon compound (C')nare used, and a small amount of propylene or ethylene and/ornan α-olefin of 4 - 20 carbon atoms for pre-activation treatmentnis supplied to the above component (A), and [II] a catalyst which is prepared by adding an organosiliconncompound (C") to the pre-activated stereoregular catalyst inna molar ratio of 0.1 - 50 as Si/Ti, is used to producenpolypropylene (propylene homopolymer) or propylene randomncopolymers (propylene-α-olefin random copolymers) with lessernformation of lump and string-like irregular shape polymers. |