Patent US4692290A successfully refreshed from Google Patents.
US4692290A
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Process for devolatilizing molten oxymethylene polymer
Assignee: Celanese Corp
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Filing: 1985-11-12
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Granted: 1987-09-08
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Expires: 2005-11-12
Abstract
Abstract A process is provided for removing volatile materials from a molten oxymethylene polymer, according to which the molten polymer is passed through a rotating disk polymer processor having at least three stages; a first devolatilization stage, then a stabilization stage and then a second devolatilization stage. The molten polymer in the first devolatilization stage is maintained at a temperature above its melting point in the temperature range of from about 160° C. to about 220° C. and at a vapor space pressure of from about 0.1 to about 300 Torr. The polymer in the stabilization stage is maintained in the molten state at a temperature of from 160° C. to about 220° C. The polymer in the second devolatilization stage is maintained in the molten state at a temperature of from about 160° C. to about 190° C. and at a vapor space pressure of from about 0.1 to about 100 Torr.
Inventors
- 👤 Douglas W. Steele
- 👤 George S. Nash
- 👤 John W. Dorsey
- 👤 Ronald S. Christy
- 👤 Timothy L. Burns
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:00
CPC Classifications
B; B29; B29B; B29B7/00; B29B7/80; B29B7/82; B01; B01D; B01D19/00; B01D19/0042; B01D19/0052; C; C08; C08G; C08G2/00; C08G2/28; Y; Y10; Y10S; Y10S264/00; Y10S264/78; Y10S525/00; Y10S525/927
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
150 words
A process for removing volatile materials from a molten oxymethylene polymer, comprising passing the molten polymer through a rotating disk polymer processor having at least three stages, the three stages comprising in sequence a first devolatilization stage, a stabilization stage and a last devolatilization stage, the molten polymer in the first devolatilization stage being maintained at a temperature above its melting point in the temperature range of from about 160° C. to about 220° C. and at a vapor space pressure of from about 0.1 to about 300 Torr, the polymer in the stabilization stage being maintained in the molten state at a temperature of from 160° C. to about 220° C., the polymer in the last devolatilization stage being maintained in the molten state at a temperature of from about 160° C. to 190° C. and at a vapor space pressure of from about 0.1 to about 100 Torr.
Claim 2
Dependent Claim
150 words
A process for removing volatile materials from a molten oxymethylene polymer, comprising passing the molten polymer through a rotating disk polymer processor having at least three stages, the three stages comprising in sequence a first devolatilization stage, a stabilization stage and a last devolatilization stage, the molten polymer in the first devolatilization stage being maintained at a temperature above its melting point in the temperature range of from about 160° C. to about 220° C. and at a vapor space pressure of from about 0.1 to about 300 Torr, the polymer in the stabilization stage being maintained in the molten state at a temperature of from 160° C. to about 220° C., the polymer in the last devolatilization stage being maintained in the molten state at a temperature of from about 160° C. to 190° C. and at a vapor space pressure of from about 0.1 to about 100 Torr.
Claim 3
Dependent Claim
41 words
The process of claim 1 further including passing the molten oxymethylene polymer through a feed stage prior to the first devolatilization stage, and, after the last devolatilization stage, passing said molten polymer through a holding stage, and then a pumping stage.
Claim 4
Dependent Claim
34 words
The process of claim 2 further including passing the molten oxymethylene polymer through a second devolatilization stage, and then a second stabilization stage, prior to the last devolatilization stage and before the holding stage.
Claim 5
Dependent Claim
41 words
The-process of claim 3 wherein the molten polymer in the second devolatilization stage is maintained at a temperature of from about 160° C. to about 220° C. and at a vapor space pressure of from about 0.1 to about 100 Torr.
Claim 6
Dependent Claim
27 words
The process of claim 4 wherein the vapor space pressure in the second devolatilization stage is maintained in the range from about 0.1 to about 50 Torr.
Claim 7
Dependent Claim
27 words
The process of claim 4 wherein the vapor space pressure in the second devolatilization stage is maintained in the range from about 0.1 to about 20 Torr.
Claim 8
Dependent Claim
24 words
The process of claim 1 wherein the vapor space pressure in the first devolatilization stage is maintained at about 1 to about 100 Torr.
Claim 9
Dependent Claim
26 words
The process of claim 1 wherein the vapor space pressure in the stabilization stage is maintained in the range from about 500 to about 2000 Torr.
Claim 10
Dependent Claim
27 words
The process of claim 1 wherein the vapor space pressure in the last devolatilization stage is maintained in the range from about 0.1 to about 50 Torr.
Claim 11
Dependent Claim
27 words
The process of claim 1 wherein the vapor space pressure in the last devolatilization stage is maintained in the range from about 0.1 to about 20 Torr.
Claim 12
Dependent Claim
26 words
The process of claim 1 wherein the temperature in the last devolatilization stage is within the range of from about 160° C. to about 175° C.
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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) | 1990-09-07 | 1991-03-09 | 1991-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-09-07 | 1995-03-09 | 1995-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-09-07 | 1999-03-09 | 1999-09-08 | $7700.00 | Window Closed / Lapsed |