US4287332A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for improving the chemical resistance of aromatic polyesters
Assignee: Eastman Chemical Co
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Filing: 1979-11-19
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Granted: 1981-09-01
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Expires: 1999-11-19
Abstract
Abstract Provess for improving the chemical resistance of copolyesters derived from aromatic dicarboxylic acids, certain substituted aromatic diols and, optionally, aromatic hydroxy acids. The process involves treating shaped objects made from the aromatic polyesters by subjecting them to a temperature sufficient to raise the surface temperature thereof to at least 275° C. and preferably 300° C. in air or other oxygen-containing atmospheres.
Inventors
- 👤 Winston J. Jackson, Jr.
- 👤 Herbert F. Kuhfuss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:23
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/88
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
135 words
Process for improving the chemical resistance of shaped objects made from aromatic polyesters, the process comprising providing a shaped object formed from a copolyester derived from aromatic dicarboxylic acids, aromatic diols, optionally aromatic hydroxy acids, and at least 5 mole percent based on all repeating units of a substituted aromatic diol containing at least one substituent selected from the group of chlorine atoms, bromine atoms, alkyl groups containing one to three carbon atoms, alkoxy groups containing one to three carbon atoms and tolyl, and subjecting said shaped object to a temperature of at least 275° C. in an oxygen-containing atmosphere to raise the surface temperature of said shaped object to at least 275° C. and maintaining said surface temperature for a period sufficient to effect modification of said surface to improve its resistance to solvents.
Claim 2
Dependent Claim
135 words
Process for improving the chemical resistance of shaped objects made from aromatic polyesters, the process comprising providing a shaped object formed from a copolyester derived from aromatic dicarboxylic acids, aromatic diols, optionally aromatic hydroxy acids, and at least 5 mole percent based on all repeating units of a substituted aromatic diol containing at least one substituent selected from the group of chlorine atoms, bromine atoms, alkyl groups containing one to three carbon atoms, alkoxy groups containing one to three carbon atoms and tolyl, and subjecting said shaped object to a temperature of at least 275° C. in an oxygen-containing atmosphere to raise the surface temperature of said shaped object to at least 275° C. and maintaining said surface temperature for a period sufficient to effect modification of said surface to improve its resistance to solvents.
Claim 3
Dependent Claim
7 words
Product of the process of claim 1.
Claim 4
Dependent Claim
20 words
Process of claim 1 wherein the surface temperature of said shaped object is raised to about 300° C. or more.
Claim 5
Dependent Claim
7 words
Product of the process of claim 3.
References Cited (Backward Citations)
US3637595A
Cited
US3975487A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-31 | 1985-03-02 | 1985-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-31 | 1989-03-02 | 1989-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-31 | 1993-03-02 | 1993-09-01 | $7700.00 | Window Closed / Lapsed |