US4142040A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Processing polyesters to minimize acetaldehyde formation
Assignee: Graham Packaging Plastic Products Inc
•
Filing: 1978-04-21
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Granted: 1979-02-27
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Expires: 1998-04-21
Abstract
Abstract During thermal processing of saturated polyesters in the molten state gaseous oxygen is excluded and as a result acetaldehyde formation is minimized.
Inventors
- 👤 Saleh A. Jabarin
- 👤 Elizabeth A. Lewis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 01:54
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/88; B; B29; B29C; B29C45/00; B29C45/0001; B29C45/17; B29C45/1701; B29C48/00; B29C48/022; B29C48/25; B29C48/285; B29C48/29; C08G63/78; B29C48/03; B29C48/09; B29K; B29K2067/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
76 words
In a process for physically processing at elevated temperatures a molten molding grade saturated polyester having ##STR7## in its backbone, the improvement which comprises minimizing acetaldehyde formation by excluding essentially all gaseous elemental oxygen from contact with said polymer including the step of purging oxygen-containing gases from the atmosphere in contact with said polyester by means of an inert gas, before raising the temperature of said polyester to the molten condition and physically working said polyester.
Claim 2
Dependent Claim
76 words
In a process for physically processing at elevated temperatures a molten molding grade saturated polyester having ##STR7## in its backbone, the improvement which comprises minimizing acetaldehyde formation by excluding essentially all gaseous elemental oxygen from contact with said polymer including the step of purging oxygen-containing gases from the atmosphere in contact with said polyester by means of an inert gas, before raising the temperature of said polyester to the molten condition and physically working said polyester.
Claim 3
Dependent Claim
18 words
The improvement of claim 1 wherein the physical processing of said polyester comprises extrusion in a screw extruder.
Claim 4
Dependent Claim
89 words
In a process for physically processing at elevated temperatures a molten molding grade poly(ethylene terephthalate) resin having in the polymer backbone a major weight portion of ethylene terephthalate units of the structure ##STR8## the improvement which comprises minimizing acetaldehyde formation by excluding essentially all gaseous elemental oxygen from contact with said polymer including the step of purging oxygen-containing gases from the atmosphere in contact with said polyester by means of an inert gas, before raising the temperature of said polyester to the molten condition and physically working said polyester.
Claim 5
Dependent Claim
89 words
In a process for physically processing at elevated temperatures a molten molding grade poly(ethylene terephthalate) resin having in the polymer backbone a major weight portion of ethylene terephthalate units of the structure ##STR8## the improvement which comprises minimizing acetaldehyde formation by excluding essentially all gaseous elemental oxygen from contact with said polymer including the step of purging oxygen-containing gases from the atmosphere in contact with said polyester by means of an inert gas, before raising the temperature of said polyester to the molten condition and physically working said polyester.
Claim 6
Dependent Claim
18 words
The improvement of claim 1 wherein the physical processing of said resin comprises extrusion in a screw extruder.
References Cited (Backward Citations)
US3846377A
Cited
US4072663A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-02-26 | 1982-08-28 | 1983-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-26 | 1986-08-28 | 1987-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-26 | 1990-08-28 | 1991-02-27 | $7700.00 | Window Closed / Lapsed |