Patent US4645824A successfully refreshed from Google Patents.
US4645824A
Expired / Lapsed
US
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Method of preparing high molecular weight polyimide, product and use
Assignee: Raytheon Co
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Filing: 1985-11-25
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Granted: 1987-02-24
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Expires: 2005-11-25
Abstract
Abstract A solvent polycondensation process of preparing polyimides of high molecular weight from dianhydrides and relatively unreactive diamines, where the reaction is carried out in a cresol as a solvent.
Inventors
- 👤 Abraham L. Landis
- 👤 Arthur B. Naselow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:02
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1039; C08G73/1003; C08G73/1007; C08G73/1028; C08G73/1032
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
65 words
In a process for reacting substantially equal molar proportions of a first reactant which is 2,2-bis(3-aminophenyl)hexafluoropropane or 2,2-bis(4-aminophenyl)hexafluropropane with a second reactant which is 4,4'-hexafluoroisopropylidene[bis(phthalic anhydride)] in a solvent for said reactants to prepare a polyimide having the recurring structural unit: ##STR9## wherein R is: ##STR10## the improvement which comprises using as said solvent, a solvent comprising cresol, said polyimide being soluble in said solvent.
Claim 2
Dependent Claim
65 words
In a process for reacting substantially equal molar proportions of a first reactant which is 2,2-bis(3-aminophenyl)hexafluoropropane or 2,2-bis(4-aminophenyl)hexafluropropane with a second reactant which is 4,4'-hexafluoroisopropylidene[bis(phthalic anhydride)] in a solvent for said reactants to prepare a polyimide having the recurring structural unit: ##STR9## wherein R is: ##STR10## the improvement which comprises using as said solvent, a solvent comprising cresol, said polyimide being soluble in said solvent.
Claim 3
Dependent Claim
23 words
The process of claim 1 wherein said reaction is carried out to form said polyimide having a molecular weight of at least 10,000.
Claim 4
Dependent Claim
23 words
The process of claim 1 wherein said reaction is carried out to form said polyimide having a molecular weight of at least 25,000.
Claim 5
Dependent Claim
14 words
The process of claim 1, 2, or 3 wherein said first reactant is 2,2-bis(3-aminophenyl)hexafluoropropane.
Claim 6
Dependent Claim
14 words
The process of claim 1, 2, or 3 wherein said solvent is essentially meta-cresol.
Claim 7
Dependent Claim
11 words
The process of claim 4 wherein said solvent is essentially meta-cresol.
Claim 8
Dependent Claim
18 words
The process of claim 1, 2, or 3 wherein said solvent is meta-cresol, ortho-cresol or a mixture thereof.
Claim 9
Dependent Claim
15 words
The process of claim 4 wherein said solvent is meta-cresol, ortho-cresol, or a mixture thereof.
Claim 10
Dependent Claim
25 words
The process of claim 1, 2, or 3 wherein said solvent is meta-cresol, ortho-cresol, mixtures thereof or a mixture of meta-cresol and/or ortho-cresol with para-cresol.
Claim 11
Dependent Claim
22 words
The process of claim 4 wherein said solvent is meta-cresol, ortho-cresol, mixtures thereof, or a mixture of meta-cresol and/or ortho-cresol with para-cresol.
Claim 12
Dependent Claim
20 words
The process of claim 1, 2, or 3 wherein said solvent comprises up to 95% by volume of a cosolvent.
Claim 13
Dependent Claim
28 words
The process of claim 1, 2, or 3 wherein said polyimide is isolated from said solvent, dissolved in a casting solvent and cast into a free-standing manipulatable film.
Claim 14
Dependent Claim
29 words
A polyimide having the recurring repeating unit: ##STR11## where R is: ##STR12## said polyimide having been prepared by the process of claim 1, followed by recovery from said solvent.
Claim 15
Dependent Claim
43 words
The process of claim 1, 2, or 3 wherein after completion of said reaction, said polyimide is isolated from said solvent, dispersed in a lacquer and said lacquer is applied to a substrate to form a coating of said polyimide on said substrate.
Claim 16
Dependent Claim
27 words
A substrate having at least a portion of its surface covered by a protective polyimide film, said film having been applied by the process of claim 14.
References Cited (Backward Citations)
US4542257A
Cited
US4569988A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-23 | 1990-08-25 | 1991-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-23 | 1994-08-25 | 1995-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-23 | 1998-08-25 | 1999-02-24 | $7700.00 | Window Closed / Lapsed |