| 摘要 |
<p>The present invention relates to a process for the preparation of a propylene homo-or copolymer, comprising the following steps: (i) feeding propylene and hydrogen, and optionally one or more comonomers, to a reactor R1, wherein the hydrogen is fed to the reactor R1 in a periodically varying amount, (ii) preparing a first fraction of the propylene homo-or copolymer in the reactor R1 in the presence of a catalyst, (iii) transferring the first fraction to a reactor R2, and (iv) preparing a second fraction of the propylene homo-or copolymer in the reactor R2, wherein the melt flow rate MFR(2.16 kg, 230°C) of the propylene homo-or copolymer is higher than the melt flow rate MFR(2.16 kg, 230°C) of the first fraction.</p> |
