US3607838A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing polyimides in glycol
Assignee: Individual
•
Filing: 1970-01-28
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Granted: 1971-09-21
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Expires: 1990-01-28
Abstract
Abstract The present invention relates to a process for producing polyimides in which both the formation of intermediate products, the polyamide acids, and also the formation of polyimides, for example, at two different temperatures, are carried out in glycol, and recovery of the pure polyimides follows through filtration and drying.
Inventors
- 👤 Jorg Strickrodt
- 👤 Ullrich Konig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:51
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1028
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
23 words
The process of claim 1 wherein the heating in step (c) is carried out at a temperature in the range of 145*-175* C.
Claim 2
Dependent Claim
24 words
The process of claim 1 wherein the recovered polyimide particles from step (d) are freed of glycol solvent by passing through steam under pressure.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |