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US5066736A
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Gas-phase alpha-olefin polymerization process in the presence of an activity retarder
Assignee: BP Chemicals Ltd
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Filing: 1989-09-05
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Granted: 1991-11-19
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Expires: 2009-09-05
Abstract
Abstract A process for the continuous polymerization of one or more alpha-olefins with a transition metal catalyst, in a reactor having a fluidized and/or mechanically stirred bed, in which a very small amount of an activity retarder, generally less than 0.1 ppm, is introduced continuously into the reactor at a flow rate which is varied with time so as to keep substantially constant either the polymerization rate or the content of transition metal in the polymer produced. Suitable activity retarders include polymerization inhibitors such as, for example, oxygen, alcohols, carbon monoxide and carbon dioxide and electron donor compounds such as amides and ethers.
Inventors
- 👤 Andre Dumain
- 👤 Jean Engel
- 👤 Laszlo Havas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:25
CPC Classifications
C; C08; C08F; C08F2/00; C08F10/00; Y; Y10; Y10S; Y10S526/00; Y10S526/901
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
146 words
A process for the continuous gas phase polymerization of one or more alpha-olefins in a reactor having a fluidized and/or mechanically stirred bed which comprises polymerizing at least one alpha-olefin in the presence of a catalyst based on a transition metal belonging to Groups IV, V or VI of the Periodic Table of elements and continuously introducing into the reactor a very small amount of an activity retarder so that the amount of activity retarder in the gaseous mixture circulating in the reactor is less than 0.1 part per million by weight, said activity retarder being introduced at a flow rate which is varied in time in response to the polymerization rate or in response to the content of the transition metal in the polymer product so as to keep substantially constant either the polymerization rate or the content of transition metal in the polymer product.
Claim 2
Dependent Claim
146 words
A process for the continuous gas phase polymerization of one or more alpha-olefins in a reactor having a fluidized and/or mechanically stirred bed which comprises polymerizing at least one alpha-olefin in the presence of a catalyst based on a transition metal belonging to Groups IV, V or VI of the Periodic Table of elements and continuously introducing into the reactor a very small amount of an activity retarder so that the amount of activity retarder in the gaseous mixture circulating in the reactor is less than 0.1 part per million by weight, said activity retarder being introduced at a flow rate which is varied in time in response to the polymerization rate or in response to the content of the transition metal in the polymer product so as to keep substantially constant either the polymerization rate or the content of transition metal in the polymer product.
Claim 3
Dependent Claim
46 words
Process according to claim 1, characterised in that the activity retarder is introduced into the reactor in an amount such that the molar ratio of the amount of activity retarder introduced to the amount of the alpha-olefin(s) introduced is from 10 -8 to 10 -5 .
Claim 4
Dependent Claim
19 words
Process according to claim 1, characterised in that the activity retarder is selected from polymerization inhibitors and electron-donor compounds.
Claim 5
Dependent Claim
33 words
Process according to claim 3, characterised in that the polymerization inhibitor is selected from carbon monoxide, carbon dioxide, carbon disulphide, carbon oxysulphide, nitrogen oxides and peroxides, alcohols, thiols, aldehydes, ketones, oxygen and water.
Claim 6
Dependent Claim
24 words
Process according to claim 3, characterised in that the electron donor compound is selected from amines, amides, phosphines, sulphoxides, sulphones, esters, ethers and thioethers.
Claim 7
Dependent Claim
26 words
Process according to claim 1, characterised in that the catalyst is a catalyst of the Ziegler-Natta type based on magnesium, halogen, titanium and/or vanadium and/or zirconium.
Claim 8
Dependent Claim
31 words
Process according to claim 1, characterised in that the catalyst is based on chromium oxide combined with a granular support based on a refractory oxide and activated by a heat treatment.
Claim 9
Dependent Claim
17 words
Process according to claim 1, characterised in that the alpha-olefin(s) contain from 2 to 8 carbon atoms.
Claim 10
Dependent Claim
30 words
Process according to claim 1, characterised in that the polymerisation is carried out at a pressure from 0.5 to 5 MPa and at a temperature from 0° to 135° C.
Claim 11
Dependent Claim
20 words
A process according to claim 1, wherein the gas phase polymerization is carried out while maintaining substantially constant operating conditions.
Claim 12
Dependent Claim
17 words
A process according to claim 6 wherein the activity retarder is oxygen, dimethyl formamide or carbon dioxide.
Claim 13
Dependent Claim
16 words
A process according to claim 7 wherein the activity retarder is carbon monoxide, oxygen, or water.
Claim 14
Dependent Claim
18 words
A process as defined in claim 6 or 7 wherein the activity retarder is oxygen or an amide.
Claim 15
Dependent Claim
16 words
A process as defined in claim 6 wherein the activity retarder is oxygen or dimethyl formamide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-11-18 | 1995-05-20 | 1995-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-18 | 1999-05-20 | 1999-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-18 | 2003-05-20 | 2003-11-19 | $7700.00 | Window Closed / Lapsed |