US4093795A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-stage isolation of high pressure polyethylene
Assignee: BASF SE
•
Filing: 1976-05-19
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Granted: 1978-06-06
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Expires: 1996-05-19
Abstract
Abstract A process for the manufacture of ethylene polymers by high pressure polymerization of ethylene, if desired mixed with other compounds copolymerizable with ethylene, and isolation of the reaction product in a multi-stage isolation zone. The molecular weight of the ethylene polymer can be varied by varying the temperature prevailing in the isolation zone. The isolation zone preferably consists of two stages, with a higher pressure prevailing in the first stage than in the second stage.
Inventors
- 👤 Oskar Buechner
- 👤 Gottfried Schlichthaerle
- 👤 Friedrich Urban
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:09
CPC Classifications
C; C08; C08F; C08F10/00; C08F10/02; C08F110/00; C08F110/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
152 words
A process for the manufacture of ethylene polymers by homopolymerization of ethylene or copolymerization of ethylene with other monomers which are copolymerizable with ethylene, in a polymerization zone at pressures of from 500 to 5,000 bars and at from 50° to 450° C, followed by isolation of the resulting polymer from the reaction mixture in a two-stage isolation zone at pressures in the first stage of the isolation zone of from 100 to 500 bars and in the second stage of the isolation zone of from 1 to 10 bars and at from 100° to 400° C, with mean product residence times of from 0.5 to 60 minutes in the different stages of the isolation zone, wherein the improvement comprises varying the temperature in the isolation zone to control the molecular weight of the ethylene polymer the temperature being raised to decrease the molecular weight and lowered to increase the molecular weight.
Claim 2
Dependent Claim
152 words
A process for the manufacture of ethylene polymers by homopolymerization of ethylene or copolymerization of ethylene with other monomers which are copolymerizable with ethylene, in a polymerization zone at pressures of from 500 to 5,000 bars and at from 50° to 450° C, followed by isolation of the resulting polymer from the reaction mixture in a two-stage isolation zone at pressures in the first stage of the isolation zone of from 100 to 500 bars and in the second stage of the isolation zone of from 1 to 10 bars and at from 100° to 400° C, with mean product residence times of from 0.5 to 60 minutes in the different stages of the isolation zone, wherein the improvement comprises varying the temperature in the isolation zone to control the molecular weight of the ethylene polymer the temperature being raised to decrease the molecular weight and lowered to increase the molecular weight.
Claim 3
Dependent Claim
25 words
A process as set forth in claim 1, wherein the temperature is varied in the first stage and is kept constant in the second stage.
Claim 4
Dependent Claim
25 words
A process as set forth in claim 1, wherein the temperature is kept constant in the first stage and is varied in the second stage.
Claim 5
Dependent Claim
19 words
A process as set forth in claim 1, wherein the temperature is raised in the first and second stage.
Claim 6
Dependent Claim
21 words
A process as set forth in claim 1, wherein the temperature is lowered in the first and in the second stage.
Claim 7
Dependent Claim
34 words
A process as set forth in claim 1, wherein the temperature in the isolation zone is varied to compensate for disturbances in the polymerization zone, whereby the molecular weight of the product remains constant.
References Cited (Backward Citations)
US2646425A
Cited
US3412080A
Cited
US3336281A
Cited
US3132120A
Cited
US3201365A
Cited
US3736305A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-05 | 1981-12-05 | 1982-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-05 | 1985-12-05 | 1986-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-05 | 1989-12-05 | 1990-06-06 | $7700.00 | Window Closed / Lapsed |