| 摘要 |
Process for the preparation of a polypropylene in a sequential polymerization process comprising at least three reactors connected in series, wherein the polymerization takes place in the presence of a Ziegler-Natta catalyst, said Ziegler-Natta catalyst comprises * a pro-catalyst comprising a compound of a transition metal (TM), a compound of a metal which metal is selected from one of the groups 1 to 3 of the periodic table (IUPAC), and an internal electron donor, * a co-catalyst (Co), and * an external donor (ED), wherein further the mol-ratio of co-catalyst (Co) to external donor (ED) [Co/ED] is in the range of above 12 to below 25, and the mol-ratio of co-catalyst (Co) to transition metal (TM) [Co/TM] is in the range of above 100 to below 200. |
