US4094862A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing thermoplastic aromatic polyimides
Assignee: National Aeronautics and Space Administration
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Filing: 1975-03-28
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Granted: 1978-06-13
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Expires: 1995-03-28
Abstract
Abstract A method of preparing insoluble thermoplastic aromatic polyimides having uniquely low softening temperatures by reacting, in a suitable solvent, an aromatic dianhydride and a meta-substituted aromatic diamine.
Inventors
- 👤 Vernon L. Bell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:06
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1028; C08G73/1057; C08G73/1064; C08G73/1067; C08G73/1071
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
168 words
A method for preparing insoluble thermoplastic aromatic polyimide film having uniquely low softening temperatures by reacting, in a suitable inert solvent, (a) an aromatic dianhydride with the structural formula ##STR5## where R is an aromatic tetravalent radical, with (b) a diamine of the structural formula ##STR6## where one or both of the amine groups is located in a meta position on the phenylene ring to the function Z, Z connects the two phenylene rings and is selected from the group consisting of ##STR7## R 2 being selected from the alkyl and aryl group, wherein the diamine-dianhydride reaction produces a viscous polymer solution and including the further step of making a film from this viscous solution, drying the film at ambient room temperatures for 4-16 hours, further drying the film in an air circulating oven for 1 hour at 100° C., and heating and maintaining the film to the temperature and range of 200° - 225° C. for at least 2 hours to effect imidization of the polymer film.
Claim 2
Independent Claim
168 words
A method for preparing insoluble thermoplastic aromatic polyimide film having uniquely low softening temperatures by reacting, in a suitable inert solvent, (a) an aromatic dianhydride with the structural formula ##STR5## where R is an aromatic tetravalent radical, with (b) a diamine of the structural formula ##STR6## where one or both of the amine groups is located in a meta position on the phenylene ring to the function Z, Z connects the two phenylene rings and is selected from the group consisting of ##STR7## R 2 being selected from the alkyl and aryl group, wherein the diamine-dianhydride reaction produces a viscous polymer solution and including the further step of making a film from this viscous solution, drying the film at ambient room temperatures for 4-16 hours, further drying the film in an air circulating oven for 1 hour at 100° C., and heating and maintaining the film to the temperature and range of 200° - 225° C. for at least 2 hours to effect imidization of the polymer film.
Claim 3
Dependent Claim
36 words
The method of claim 1 and including the further step of subjecting the polymer to a temperature in the range of 250°-300° C. to further cure the polymer to a glass transition temperature above 250° C.
Claim 4
Dependent Claim
30 words
The method of claim 1 wherein the aromatic dianhydride is 3,3',4,4'-benzophenone tetracarboxylic dianhydride and the diamine is selected from a group consisting of 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminodiphenyl methane, and 3,4'-diaminodiphenyl methane.
Claim 5
Dependent Claim
49 words
The method of claim 1 including the further steps of shaping an article from the polymer and curing this article in the temperature range of 250°-400° C. for at least an hour whereby the shaped article will be cured to thereby retain its shape at temperatures below 250° C.
Claim 6
Dependent Claim
32 words
The method of claim 1 wherein the aromatic dianhydride is selected from the group consisting of pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride, bis(3,4-dicarboxyphenyl) ether dianhydride, bis(3,4-dicarboxyphenyl) sulfone dianhydride and bis(3,4-dicarboxylphenyl) methane dianhydride.
Claim 7
Dependent Claim
24 words
The method of claim 1 wherein the diamine is selected from the group consisting of: 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenyl ether, and 3,4'-diaminodiphenyl ether.
References Cited (Backward Citations)
US3179614A
Cited
US3666709A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-12 | 1981-12-12 | 1982-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-12 | 1985-12-12 | 1986-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-12 | 1989-12-12 | 1990-06-13 | $7700.00 | Window Closed / Lapsed |