US4230819A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Eliminating acetaldehyde from crystalline polyethylene terephthalate resin
Assignee: Shell USA Inc
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Filing: 1979-04-13
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Granted: 1980-10-28
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Expires: 1999-04-13
Abstract
Abstract The invention relates to the removal of acetaldehyde from crystalline polyethylene terephthalate granules by passing a dry inert gas through a bed of resin at a temperature of 170 DEG C. to 250 DEG C. for a time sufficient to remove the aldehydes.
Inventors
- 👤 Jack D. Hauenstein
- 👤 Thomas E. Broderick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:46
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/88; C08G63/90
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
49 words
The method of removing acetaldehyde from crystalline polyethylene terephthalate resin which comprises passing a dry inert gas through a bed of said resin at a temperature of from about 170° C. to about 250° C. in an amount sufficient to remove acetaldehyde and other degradation products from said resin.
Claim 2
Independent Claim
49 words
The method of removing acetaldehyde from crystalline polyethylene terephthalate resin which comprises passing a dry inert gas through a bed of said resin at a temperature of from about 170° C. to about 250° C. in an amount sufficient to remove acetaldehyde and other degradation products from said resin.
Claim 3
Dependent Claim
13 words
The method of claim 1 in which the gas used is dry air.
Claim 4
Dependent Claim
13 words
The method of claim 1 in which the gased used is dry nitrogen.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-28 | 1984-04-28 | 1984-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-28 | 1988-04-28 | 1988-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-28 | 1992-04-28 | 1992-10-28 | $7700.00 | Window Closed / Lapsed |