US5051528A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery process for ethylene glycol and dimethylterephthalate
Assignee: Eastman Kodak Co
•
Filing: 1990-04-24
•
Granted: 1991-09-24
•
Expires: 2010-04-24
Abstract
Abstract A method of recovering ethylene glycol and dimethyl terephthalate from scrap polyethylene terephthalate resins by dissolving the scrap in oligomers of the same monomers and passing methanol through the solution.
Inventors
- 👤 Andrius A. Naujokas
- 👤 Kevin M. Ryan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:58
CPC Classifications
C; C07; C07C; C07C67/00; C07C67/03
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
40 words
A method of recovering ethylene glycol and dimethylterephthalate from polyethyleneterephthalate polyesters which comprises dissolving scrap polyester in oligomers of ethylene glycol and terephthalic acid or dimethyl terephthalate, passing super-heated methanol through the solution and recovering the ethylene glycol and dimethylterephthalate.
Claim 2
Independent Claim
40 words
A method of recovering ethylene glycol and dimethylterephthalate from polyethyleneterephthalate polyesters which comprises dissolving scrap polyester in oligomers of ethylene glycol and terephthalic acid or dimethyl terephthalate, passing super-heated methanol through the solution and recovering the ethylene glycol and dimethylterephthalate.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein the process is conducted under atmospheric pressure.
Claim 4
Dependent Claim
25 words
The process of claim 1 wherein the scrap is heated to a temperature of from about 20° to 270° C. during the contact with methanol.
Claim 5
Dependent Claim
16 words
The method of claim 1 wherein an excess quantity of methanol is passed through the solution.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein the ethylene glycol and dimethylterephthalate are recovered by distillation.
References Cited (Backward Citations)
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US3488298A
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Cited
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Cited
US4578502A
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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) | 1994-09-23 | 1995-03-25 | 1995-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-23 | 1999-03-25 | 1999-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-23 | 2003-03-25 | 2003-09-24 | $7700.00 | Window Closed / Lapsed |