Patent US3554935A successfully refreshed from Google Patents.
US3554935A
Expired / Lapsed
US
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Polyimide foams
Assignee: Monsanto Co
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Filing: 1968-03-12
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Granted: 1971-01-12
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Expires: 1988-03-12
Abstract
Abstract DISCLOSED HEREIN ARE POLYIMIDE FOAMS PREPARED FROM A MIXTURE OF (1) AN A-STAGED POLYIMIDE RESIN FORMING COMPOSITION HAVING A VOLATILE CONTENT OF AT LEAST 9% BY WEIGHT, AND (2) A B-STAGED POLYIMIDE RESIN HAVING A VOLATILE CONTENT OF LESS THAN 9% BY WEIGHT. THE MIXTURE IS HEATED TO AT LEAST THAT TEMPERATURE WHERE FOAMING OCCURS CONTEMPORANEOUSLY WITH THE POLYMERIZATION OF THE A-STAGED SYSTEM, TO FORM A POLYIMIDE FOAM HAVING A DENSITY UP TO 70 LBS./CU. FT.
Inventors
- 👤 Edmund C Knapp
- 👤 Albert H Markhart
- 👤 Irving Serlin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:33
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/02; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08J2379/00; C08J2379/04; C08J2379/08; Y; Y10; Y10S; Y10S525/00; Y10S525/928
Claims Analysis
Total Claims: 0
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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) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |