Some peculiar aspects of a new catalyst for propene polymerization

An investigation was carried out on the preparation of highly disordered samples of MgCl2 (in delta -form), starting from different Mg-alkyls and chlorinating agents. Successively we studied which kind of silica carrier had to be preferred and which treatment was strictly' necessary to achieve a qualified catalyst precursor showing outstanding performance. Different routes were investigated to support the active, disordered MgCl2 on the silica carrier and then some following ways to complete the catalyst. The final result of this investigation was the synthesis of a catalyst showing the best performance with reference to the parameters of use in every polymerization process. It has to be e.g. mentioned: — high yield, referred to the residual content of Mg, Ti and Cl; — no activity decrease when operating at a very high hydrogen concentration; — possibility to polymerize also at elevated temperatures; — very high isotactic index and stereoregular structure, as measured by the NMR technique; — possibility to reach high MFR (Melt Flow Rate) (up to 400 g IPP/10 min at 230°C, 2,16 kg, ASTM D 1238L); — outstanding morphology and flowability.