Process for producing a polypropylene homo- or copolymer

Process for the production of a polypropylene homo- or copolymer, the process comprising the steps of

• a) prepolymerising propylene in a first reactor in the presence of hydrogen and a metallocene catalyst yielding a first polypropylene homo- or copolymer fraction, wherein a ratio of the feed of hydrogen to the feed of propylene is in the range of 0.01 to 0.08 mol/kmol, and wherein the temperature in the first reactor is from 15 to 29° C.,
• b) transferring the first polypropylene homo- or copolymer fraction to a second reactor,
• c) polymerising in the second reactor propylene in the presence of the first polypropylene homo- or copolymer fraction, yielding a second polypropylene homo- or copolymer fraction, wherein a residence time in the second reactor is from 10 to 40 min,
• d) withdrawing the polypropylene homo- or copolymer comprising the first and the second polypropylene homo- or copolymer fraction from the second reactor or transferring the polypropylene homo- or copolymer to a third reactor,
• wherein metallocene catalyst comprises a metallocene complex, and the metallocene complex is an organometallic compound (C), the organometallic compound (C) has the following formula (Ia):
• wherein
• “M” is Zr or Hf;
• each “X” is a σ-ligand;
• each “L” is an optionally substituted cyclopentadienyl, indenyl or tetrahydroindenyl;
• “R” is SiMe2 bridging group linking said organic ligands (L);
• “n” is 0 or 1, preferably 1.