Patent US4128535A successfully refreshed from Google Patents.
US4128535A
Expired / Lapsed
US
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Method for reducing color formation in polyesters
Assignee: EIDP Inc
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Filing: 1977-09-19
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Granted: 1978-12-05
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Expires: 1997-09-19
Abstract
Abstract Color formation in a polyester formed of a saturated acid, a glycol and 1,4-butanediol can be reduced if, during preparation of the polyester, a reaction mass is first formed of the acid and the glycol and the butanediol is then added to the reaction mass after the acid-glycol reaction is practically complete.
Inventors
- 👤 Melvin C. Baker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:00
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/02; C08G63/12; C08G63/16
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
83 words
In the preparation of a polyester wherein adipic acid, glutaric acid or succinic acid or mixtures thereof; ethylene glycol, propylene glycol or mixtures thereof; and 1,4-butanediol are brought together under conditions suitable for condensation polymerization, a method for reducing undesirable color formation in the polyester product, the method consisting essentially of first forming a reaction mass of the acid and the glycol and then adding the butanediol to the reaction mass after the reaction between the acid and the glycol is practically complete.
Claim 2
Dependent Claim
83 words
In the preparation of a polyester wherein adipic acid, glutaric acid or succinic acid or mixtures thereof; ethylene glycol, propylene glycol or mixtures thereof; and 1,4-butanediol are brought together under conditions suitable for condensation polymerization, a method for reducing undesirable color formation in the polyester product, the method consisting essentially of first forming a reaction mass of the acid and the glycol and then adding the butanediol to the reaction mass after the reaction between the acid and the glycol is practically complete.
Claim 3
Dependent Claim
17 words
The method of claim 1, wherein the polyester is formed of adipic acid, ethylene glycol and 1,4-butanediol.
Claim 4
Dependent Claim
18 words
The method of claim 2 wherein the acid, glycol and 1,4-butanediol are used in mol ratios of 1/1.1-1.3/0.35-0.5.
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) | 1981-12-04 | 1982-06-05 | 1982-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-04 | 1986-06-05 | 1986-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-04 | 1990-06-05 | 1990-12-05 | $7700.00 | Window Closed / Lapsed |