US3684766A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for enhancing the inherent viscosity of bisphenol polyesters
Assignee: Eastman Kodak Co
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Filing: 1970-02-16
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Granted: 1972-08-15
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Expires: 1990-02-16
Abstract
Abstract A bisphenol polyester with an inherent viscosity of at least about 0.5 is produced by the steps of (1) preparing a bisphenol polyester with an inherent viscosity of at least about 0.1, (2) comminuting the prepared polyester (3) contacting the comminuted polyester with a crystallizing agent, and (4) heating the crystallized polyester in the presence of an inert gas to increase the inherent viscosity to at least 0.5. Preferably a copolyester of bisphenol A, terephthalic and isophthalic acid is used and the heating step is accomplished by fluidizing the crystallized polymer in the same vessel as used for crystallization.
Inventors
- 👤 Winston J Jackson Jr
- 👤 Herbert F Kuhfuss
- 👤 John R Caldwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:35
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/02; C08G63/12; C08G63/16; C08G63/18; C08G63/19; C08G63/88
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
134 words
a bisphenol diester of a bisphenol and a monocarboxylic acid containing from one to eight carbon atoms; B. crystallizing the comminuted polyester by contacting at a temperature of from about room temperature to 150* C. with a crystallizing agent having a boiling point from about 40*-300*C. and a solubility parameter from about 8-12 and selected from the group consisting of nonhalogenated ketones, non-halogenated aliphatic carboxylic acids, non-halogenated esters of carbonic and carboxylic acid and non-halogenated aromatic hydrocarbons having one to 15 carbon atoms; C heating the resulting crystallized polyester particles at a temperature of said particles while passing an inert gas therethrough to increase the inherent viscosity of the polyester to at least about 0.5 as determined at 25* C in 60/40 parts by weight of phenol/tetrachloroethane at a concentration of 0.25 g/100 ml.
Claim 2
Dependent Claim
123 words
The process of claim 1 wherein The monocarboxylic acid is selected from the group consisting of formic, acetic, propionic, butyric and benzoic acid and mixtures thereof, the dicarboxylic acid is selected from the group consisting of terephthalic acid, isophthalic acid, 5-tert-butylisophthalic acid, diphenic acid, 4,4''-methylenedibenzoic acid, 4,4''-oxydibenzoic acid, 4,4''-sulfonyl-dibenzoic acid, naphthalenedicarboxylic acids, chloroterephthalic acid, dichlorotere-phthalic acid, and mixtures thereof, the bisphenol is selected from the group consisting of 4,4''-isopropylidenediphenol, 4,4''-thiodiphenol, 4,4''-dihydroxybiphenyl, 4,4''-oxydiphenol, 4,4''-methylenediphenol, 4, 4''-dihydroxybiphenyl, 4,4''-(2-norbornylidene)-diphenol, 4,4''-isopropylidenebis(2,6hydroquinone, resorcinol, and naphthalenediols and mixtures thereof, and the crystallizing agent has a solubility parameter from about 8-12 and is selected from the group consisting of nonhalogenated ketones, nonhalogenated aliphatic carboxylic acids, nonhalogenated esters of carbonic and carboxylic acid and nonhalogenated aromatic hydrocarbons having 1-15 carbon atoms.
Claim 3
Dependent Claim
95 words
Process according to claim 1 wherein said polyester is prepared from about 65 mole percent terephthalic acid and about 35 mole percent isophthalic acid based on the total moles of dicarboxylic acid, and 4,4''-isopropylidenediphenol; the crystallizing agent is acetic acid which is contacted with the comminuted polyester at a temperature of at least about 80* C; the crystallized polyester is fluidized by said inert gas and is heated to within a temperature range of about 25*-270* C; the contact with the crystallizing agent and the fluidizing and heating all occuring within the same processing zone.
Claim 4
Dependent Claim
28 words
Process of claim 1 wherein the contacting with the crystallizing agent and the heating in the presence of an inert gas take place within the same processing zone.
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) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |