Patent ID: 6875826

Claim:
A process for preparing linear high melt strength propylene homopolymers and copolymers, comprising the steps of subjecting propylene and optionally other olefins to polymerization in a plurality of polymerization reactors connected in series wherein said reactors are selected from the group consisting of loop reactors and gas phase reactors and wherein said reactors comprise at least one loop reactor and at least one gas phase reactor, employing different amounts of hydrogen as a molar mass modifier in at least two of the reactors, and carrying out the polymerization reaction in the presence of a catalyst system which catalyzes the formation of a high molar mass polymerization product having a MFR 2 of less than 0.1 g/10 ml and a low or medium molar mass polymerization product having a MFR 2 of more than 0.5 g/10 min, wherein the second polymerization product is fed into a third reactor and propylene is subjected to a third polymerization reaction to produce a third polymerization product.