Process for the gas-phase polymerization of olefins
US6228956A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | May 8, 2001 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F210/16
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Process for the gas-phase polymerization of olefins of the formula CH.sub.2.dbd.CHR where R is hydrogen or an alkyl or aryl radical with 1 to 8 carbon atoms carried out in one or more reactors having a fluidized or mechanically agitated bed, using a catalyst obtained by reaction of a titanium halide or haloalcoholate and optionally an electron-donor compound supported on an active Mg-dihalide with an Al-trialkyl compound and optionally an electron-donor compound, comprising the steps of: PA1 a) contacting the catalyst components in the absence of polymerizable olefin or optionally in the presence of said olefin in an amount to from up to 3 g per g of solid catalyst component; PA1 b) prepolymerizing propylene or mixtures of propylene with ethylene or an alpha-olefin to form a propylene polymer having an insolubility in xylene of at least 60% by weight, in an amount of from 5 g of polymer per g of solid catalyst component to 10% by weight of the final catalyst yield; and PA1 c) polymerizing one or more CH.sub.2.dbd.CHR olefins in the gas phase in the presence of the prepolymer-catalyst system obtained in b), while maintaining in the gas phase an alkane in a molar concentration with r…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.