Patent US3988374A successfully refreshed from Google Patents.
US3988374A
Expired / Lapsed
US
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Polyamide-imides
Assignee: BP Corp North America Inc
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Filing: 1971-09-21
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Granted: 1976-10-26
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Expires: 1991-09-21
Abstract
Abstract A series of polyamide-imides which are both tractable and soluble in polar solvents as well as stable at high temperatures has been prepared by the condensation polymerization of aromatic diamines or oligomers containing oxygen, sulfone, and optionally alkylidene linkages with trimellitic acid, trimellitic acid anhydride or trimellitic anhydride acid chloride.
Inventors
- 👤 George L. Brode
- 👤 James H. Kawakami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:04
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/14
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
6 words
An amine having the formula: ##SPC34##
Claim 2
Dependent Claim
6 words
An amine having the formula: ##SPC34##
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) | 1979-10-26 | 1980-04-26 | 1980-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-26 | 1984-04-26 | 1984-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-26 | 1988-04-26 | 1988-10-26 | $7700.00 | Window Closed / Lapsed |