Polymerization process
US6921798B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 2003 |
| Grant date | Jul 26, 2005 |
| Priority date | — |
| Expiry date | Jun 6, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F210/16
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Polymerization processes are disclosed for producing polyethylene having a target density and improved environmental stress resistance. Ethylene and optionally one or more α-olefin comonomers, supported chromium catalyst, and metal alkyl cocatalyst are contacted to produce polyethylene. The density of the polyethylene is determined, and the concentration of cocatalyst is adjusted in response to a deviation between the density of the polyethylene and the target density. The catalyst and cocatalyst can be fed separately into the reactor, or can be co-fed, eliminating the need to pre-contact the catalyst and cocatalyst prior to introducing them into the reactor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.