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Patent US4166170A successfully refreshed from Google Patents.
US4166170A
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Mixed diamines for lower melting addition polyimide preparation and utilization
Assignee: National Aeronautics and Space Administration
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Filing: 1977-10-06
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Granted: 1979-08-28
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Expires: 1997-10-06
Abstract
Abstract A novel addition polyimide based on the use of liquid monomers wherein the essentially solventless prepreg produced therefrom retains good drape, tack and other mechanical properties.
Inventors
- 👤 Terry L. St. Clair
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:00
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1028; C08G73/1075; C08G73/1082
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
53 words
A liquid composition of matter consisting essentially of an equimolar mixture of benzophenonetetracarboxylic acid diahydride and norbornene dicarboxylic acid anhydride reacted at 75°-80° C. in an excess of ethanol and thereafter cooled to room temperature and mixed with a mixture of the isomers of methylenedianilines in the following percentages: o,o'--MDA--3.20% o,p'--MDA--15.70% p,p'--MDA--66.00% ##STR6##
Claim 2
Dependent Claim
53 words
A liquid composition of matter consisting essentially of an equimolar mixture of benzophenonetetracarboxylic acid diahydride and norbornene dicarboxylic acid anhydride reacted at 75°-80° C. in an excess of ethanol and thereafter cooled to room temperature and mixed with a mixture of the isomers of methylenedianilines in the following percentages: o,o'--MDA--3.20% o,p'--MDA--15.70% p,p'--MDA--66.00% ##STR6##
Claim 3
Dependent Claim
21 words
A composition of matter as in claim 1 wherein the average molecular weight for the mixture of methylene dianilines is 234.
Claim 4
Independent Claim
88 words
A method for preparing a novel addition type polyimide comprising the steps of reacting equimolar quantities of benzophenonetetracarboxylic acid dianhydride and norbornene diacarboxylic acid anhydride in an excess of absolute ethanol while heating to 50°-60° C. until solution occurs, cooling the resulting solution of ethylesters to room temperature and adding the cooled solution to a vessel containing an equimolar solution of mixed dianilines, stirring the combined solution for approximately one hour to obtain a homogeneous ester-acid polyimide prepolmer adaptable for "hot-melt" prepreg applications as a liguid resin system.
Claim 5
Independent Claim
88 words
A method for preparing a novel addition type polyimide comprising the steps of reacting equimolar quantities of benzophenonetetracarboxylic acid dianhydride and norbornene diacarboxylic acid anhydride in an excess of absolute ethanol while heating to 50°-60° C. until solution occurs, cooling the resulting solution of ethylesters to room temperature and adding the cooled solution to a vessel containing an equimolar solution of mixed dianilines, stirring the combined solution for approximately one hour to obtain a homogeneous ester-acid polyimide prepolmer adaptable for "hot-melt" prepreg applications as a liguid resin system.
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) | 1982-08-27 | 1983-02-26 | 1983-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-27 | 1987-02-26 | 1987-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-27 | 1991-02-26 | 1991-08-28 | $7700.00 | Window Closed / Lapsed |