US3926913A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low temperature curing polyimides
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1974-02-15
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Granted: 1975-12-16
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Expires: 1994-02-15
Abstract
Abstract A low temperature curing, linear polyimide is produced by substituting diaminostilbene not in excess of 50 mole percent for the primary diamine in the polyimide backbone chain, and upon curing in the presence of a free radical producing catalyst, and optionally, an ethylenically terminated cross-linking agent, a high performance, thermosetting polyimide is formed.
Inventors
- 👤 Robert J Jones
- 👤 Howard N Cassey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:58
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/12; C08G73/121; C08G73/122
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
114 words
A PROCESS FOR THE PREPARATION OF A LOWER TEMPERATURE CURING POLYIMIDE COMPRISING: A. BLENDING AN ORGANIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF DISNHYDRIDE AND TETRAACID AND A FREE RADICAL CATALYST WITH DIAMINOSTILBENE NOT IN EXCESS OF 50 MOLE PERCENT AND THE REMAINDER A NITROGEN COMPOUND SELECTED FROM THE GROUP CONSISTING OF ORGANIC DIISOCYANATE AND ORGANIC PRIMARY DISMINES WHEREBY A MIXTURE OF AN AMIDEACID WITH THE CATALYST DISPERSED THERETHROUGH IS FORMED; B. SUBSEQUENTLY HEATING THE MIXTURE IN A TEMPERATURE RANGE OF FRM 150* TO 200*C TO IMIDIZE SAID AMIDE-ACID FULLY; AND C. HEATING SAID IMIDE-CATALYST IN A TEMPERATURE RANGE OF FROM 150* TO 250*C TO ACTIVATE SAID CATALYST WHEREBY A COMPLIANT POLYIMIDE IS FORMED.
Claim 2
Dependent Claim
114 words
A PROCESS FOR THE PREPARATION OF A LOWER TEMPERATURE CURING POLYIMIDE COMPRISING: A. BLENDING AN ORGANIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF DISNHYDRIDE AND TETRAACID AND A FREE RADICAL CATALYST WITH DIAMINOSTILBENE NOT IN EXCESS OF 50 MOLE PERCENT AND THE REMAINDER A NITROGEN COMPOUND SELECTED FROM THE GROUP CONSISTING OF ORGANIC DIISOCYANATE AND ORGANIC PRIMARY DISMINES WHEREBY A MIXTURE OF AN AMIDEACID WITH THE CATALYST DISPERSED THERETHROUGH IS FORMED; B. SUBSEQUENTLY HEATING THE MIXTURE IN A TEMPERATURE RANGE OF FRM 150* TO 200*C TO IMIDIZE SAID AMIDE-ACID FULLY; AND C. HEATING SAID IMIDE-CATALYST IN A TEMPERATURE RANGE OF FROM 150* TO 250*C TO ACTIVATE SAID CATALYST WHEREBY A COMPLIANT POLYIMIDE IS FORMED.
Claim 3
Dependent Claim
16 words
A process according to claim 1 wherein said catalyst is added after said amide-acid is formed.
Claim 4
Dependent Claim
42 words
A process according to claim 1 wherein a cross-linking agent having terminally positioned ethylene substituents selected from the group consisting of olefins, bis(male)-imides, divinylbenzene, and fluoro-substituted divinylbenzene is blended into the initial mixture in amounts up to equal molar with said diaminostilbene.
Claim 5
Dependent Claim
20 words
A process according to claim 1 wherein said organic compound has the structural formula selected from the group consisting of
Claim 6
Dependent Claim
33 words
A process according to claim 1 wherein said organic primary diamine has the structural formula of H2N - R1 - NH2 wherein R1 is a difunctional radical selected from the group consisting of
Claim 7
Dependent Claim
31 words
A process according to claim 1 wherein said organic diisocyanate has the structural formula O C N-R8-N C O wherein R8 is a difunctional radical selected from the group consisting of
Claim 8
Dependent Claim
15 words
A process according to claim 1 wherein said free radical catalyst is an organic peroxide.
Claim 9
Dependent Claim
20 words
A process according to claim 1 wherein said diaminostilbene is present in amounts ranging from 10 to 20 mole percent.
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) | 1978-12-15 | 1979-06-16 | 1979-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-15 | 1983-06-16 | 1983-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-15 | 1987-06-16 | 1987-12-16 | $7700.00 | Window Closed / Lapsed |