Patent EP0202951A2 successfully refreshed from Google Patents.
Patent US3624050A successfully refreshed from Google Patents.
US3624050A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing polyimides via polyamide acids without use of solvents
Assignee: Individual
•
Filing: 1970-01-28
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Granted: 1971-11-30
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Expires: 1990-01-28
Abstract
Abstract Process for producing polyimides by treating a dianhydride and a diprimary amine at a temperature in the range of 20* C. to 120* C. in the absence of a solvent and with continuous mixing to form a polyamide acid and converting the polyamide acid to the corresponding polyimide by heating the polyamide acid at a temperature in the range of 0 to 20* above the maximum temperature difference shown by the polyamide acid under differential thermal analysis.
Inventors
- 👤 Jorg Strickrodt
- 👤 Ullrich Konig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:41
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1075; C08G73/1082; C08G73/1003; C08G73/1007; C08G73/1028
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
44 words
The process of claim 1 wherein the polyamide acid is converted to the corresponding polyimide by heating the polyamide acid at a temperature in the range of 0* to 20* above the maximum temperature difference shown by the polyamide acid under differential thermal analysis.
Claim 2
Dependent Claim
26 words
The process of claim 1 wherein the grain sizes of the starting materials for production of the polyamide acid are not greater than about 0.8 mm.
Claim 3
Dependent Claim
17 words
The process of claim 1 wherein said temperature is between about 20* C. and about 120* C.
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) | 1974-11-29 | 1975-05-31 | 1975-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-29 | 1979-05-31 | 1979-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-29 | 1983-05-31 | 1983-11-30 | $7700.00 | Window Closed / Lapsed |