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US3669937A
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US
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Process for the production of polyimides
Assignee: Bayer AG
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Filing: 1969-03-26
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Granted: 1972-06-13
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Expires: 1989-03-26
Abstract
Abstract Process for the production of polyimides by reaction of a urea and a cyclic dicarboxylic acid anhydride containing at least one additional functional group capable of condensation or addition.
Inventors
- 👤 Wilfried Zecher
- 👤 Rudolf Merten
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:58
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
99 words
a cyclic dicarboxylic acid anhydride containing at least one additional functional group capable of condensation or addition selected from the group consisting of cyclic dicarboxylic acid anhydride, carboxylic acid and carboxylic acid ester groups; at a temperature of from -20* to +450* C in the presence of an organic solvent selected from the group consisting of hydrocarbons, halogenated hydrocarbons, phenols, esters, ketones, ethers, substituted amines, sulfoxides, sulfones and mixtures thereof in which said resulting high molecular weight polyimide contains recurring imide groups, the N-atom of which is derived from the N-atom in a urea group of said urea reactant.
Claim 2
Dependent Claim
19 words
The process of claim 1 wherein the reaction is carried out at a temperature of 20* to 350* C.
Claim 3
Dependent Claim
22 words
The process of claim 1 wherein said urea comprises the reaction product of a diisocyanate with a diamine, an aminoalcohol or water.
Claim 4
Dependent Claim
41 words
The process of claim 1 wherein said urea comprises the reaction product of an isocyanate selected from the group consisting of diphenylmethane-4,4''-diisocyanate and hexamethylene diisocyanate; with an amine selected from the group consisting of 4,4''-diamino diphenylmethane, hexamethylene diamine and a aminoethanol.
Claim 5
Dependent Claim
28 words
The process of claim 1 wherein said cyclic dicarboxylic acid anhydride is selected from the group consisting of trimellitic acid anhydride, pyromellitic acid dianhydride and azo-bis-4,4''-phthalic acid anhydride.
References Cited (Backward Citations)
US3300420A
Cited
US3317480A
Cited
US3314923A
Cited
US3493540A
Cited
BE672985A
Cited
US3489696A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |