Method to produce very stiff polypropylene
US8557917B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 6, 2009 |
| Grant date | Oct 15, 2013 |
| Priority date | — |
| Expiry date | Apr 18, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F2400/02
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.