Process for the polymerisation of ethylene or the copolymerisation of ethylene and alpha-olefins in a fluidised bed in the presence of a chromium based catalyst
US4910271A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1985 |
| Grant date | Mar 20, 1990 |
| Priority date | — |
| Expiry date | Sep 16, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2998
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The present invention relates to a process for the polymerisation of ethylene or copolymerisation of ethylene and at least one other alpha-olefin, in the gas phase in a fluidised bed reactor, in the presence of a catalyst comprising chromium compounds associated with a granular support comprising a refractory oxide and activated by thermal treatment, which process is characterised in that the catalyst is used in the form of active particles of prepolymer, obtained by bringing the said catalyst in contact with ethylene, alone, or in a mixture with at least one higher alpha-olefin, in such a way that the prepolymer contains from 4.times.10.sup.-5 to 3 milligram atoms of chromium in the catalyst per gram.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.