Patent US3719640A successfully refreshed from Google Patents.
US3719640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Poly(amide-imide)polymers having recurring diketopiperazine groups
Assignee: Honeywell International Inc
•
Filing: 1971-07-21
•
Granted: 1973-03-06
•
Expires: 1991-07-21
Abstract
Abstract NOVEL LINEAR POLYMERS CONTAINING RECURRING DIKETOPIPERAZINE GROUPS ARE PREPARED BY POLYMERIZING THE SALT OF A DIAMINE AND A NITRILOTRICARBOXYLIC ACID HAVING THE FORMULA HOOCRN(CH2COOH)2 WHEREIN R IS A PHENYLENE OR ALKYLENE RADICAL. THE POLYMERS CONTAIN QUATERNIZABLE TERTIARY NITROGEN ATOMS WHICH IMPART VALUABLE PROPERTIES TO THE POLYMERS. THE POLYMERS MAY BE FORMED INTO FIBERS, FILMS AND SHAPED ARTICLES, AND MAY BE BLENDED WITH OTHER POLYMERS TO IMPROVE THEIR PROPERTIES.
Inventors
- 👤 L Lee
- 👤 S Hirsch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:32
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/14; C08G69/00; C08G69/48; Y; Y10; Y10S; Y10S525/00; Y10S525/917
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1976-03-05 | 1976-09-04 | 1977-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-05 | 1980-09-04 | 1981-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-05 | 1984-09-04 | 1985-03-06 | $7700.00 | Window Closed / Lapsed |