Multistep process for preparing polyolefins having high melt strength
US6573343B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 15, 2001 |
| Grant date | Jun 3, 2003 |
| Priority date | — |
| Expiry date | Jun 15, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S526/905
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Olefin polymers are prepared in a plurality of polymerization stages, optionally in a plurality of polymerization reactors, in the presence of hydrogen and an olefin polymerization multisite catalyst, preferably a dualsite catalyst, having at least catalytic sites A and B, site A capable of yielding polymers of different molecular weights and differing MFR2 or MFR21 depending on the concentration of hydrogen in the polymerization reactor and site B capable of yielding polymers of certain molecular weight and MFR2 or MFR21 depending on the concentration of hydrogen in the polymerization reactor where the ratio between MFR2 or MFR21 of polymers produced by site B at two different selected hydrogen concentrations is less than ten and the ratio between MFR2 or MFR21 of polymers produced by site A at the same hydrogen concentrations is more than 50.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.