Prepolymers of olefins containing a chromiumoxide and a granular refractory oxide support
US5165998A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 2, 1990 |
| Grant date | Nov 24, 1992 |
| Priority date | — |
| Expiry date | Jan 2, 2010 |
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 polymerization of ethylene or copolymerization of ethylene and at least one other alpha-olefin, in the gas phase in a fluidized 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 characterized 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.