EP0359444A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Gas-phase alpha-olefin polymerization process in the presence of an activity retarder
Assignee: BP Chemicals Ltd
•
Filing: 1989-08-31
•
Granted: —
•
Expires: 2009-08-31
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
- 👤 Laszlo Havas
- 👤 Jean Engel
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 17:35
CPC Classifications
C; C08; C08F; C08F2/00; C08F10/00; Y; Y10; Y10S; Y10S526/00; Y10S526/901
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
115 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, with the aid of a catalyst and of an activity retarder, characterised in that the polymerization is carried out by bringing a catalyst based on a transition metal belonging to groups IV, V or VI of the Periodic Classification of the elements into contact with the alpha-olefin(s) and a very small amount of the activity retarder which 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.
Claim 2
Dependent Claim
115 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, with the aid of a catalyst and of an activity retarder, characterised in that the polymerization is carried out by bringing a catalyst based on a transition metal belonging to groups IV, V or VI of the Periodic Classification of the elements into contact with the alpha-olefin(s) and a very small amount of the activity retarder which 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.
Claim 3
Dependent Claim
43 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 10⁵.
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
29 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.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.