| abstract |
A gas-phase process for the homo or copolymerization of propylene with other olefins, carried out in the presence of a catalyst system comprising: (a) a solid catalyst component comprising Mg, Ti, halogen, an electron donor selected from 1.3-diethers and an olefin polymer in a specific amount; (b) an aluminum alkyl compound and (c) an external electron donor compound selected from specific classes; said components (a) and (c) being employed in amounts such that the Al/(ED) molar ratio ranges from 2 to 200. The process is capable to give polypropylene product having good morphological properties, high stereoregularity, and capable to show self- extinguishing properties such that the negative effects caused by the fine catalyst particle polymerization can be selectively solved or mitigated. |