US4980389A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyetherimide foam precursors and foams having improved physical properties and methods of making them
Assignee: Irbit Research and Consulting AG
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Filing: 1990-04-03
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Granted: 1990-12-25
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Expires: 2010-04-03
Abstract
Abstract A method of making polyetherimide foam precursors and flexible polyetherimide foams having improved specific tensile strength, resistance to high temperatures and flame, low density and flexibility at both high and cryogenic temperatures. 4,4'-oxydiphthalic anhydride (ODPA) is reacted with an alcohol to produce a diester, which is then reacted with a suitable monomeric polyamine such as meta phenylene diamine to produce a precursor. This material is dried to a solid block or powder. Upon heating, foaming occurs, resulting in a fine celled white friable mass. The foam is cured by heating for a suitable period and is ready for use.
Inventors
- 👤 Francis U. Hill
- 👤 Paul F. Schoenzart
- 👤 Werner P. Frank
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:32
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1067; C08G73/1071; C08G73/1046; C08G73/1053
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
79 words
The method of making a polyimide foam precursor which comprises the steps of: converting 4,4'-oxydiphthalic anhydride and corresponding isomers by reaction with a C 1 -C 7 -alcohol in a suitable solvent to the corresponding ester derivatives of 4,4'-oxydiphthalic acid and corresponding isomers; reacting said ester derivatives with a polyamine in a suitable solvent at a temperature ranging from about ambient temperature to about 50° C.; and removing the solvent at least partially to obtain the polyimide foam precursor.
Claim 2
Independent Claim
79 words
The method of making a polyimide foam precursor which comprises the steps of: converting 4,4'-oxydiphthalic anhydride and corresponding isomers by reaction with a C 1 -C 7 -alcohol in a suitable solvent to the corresponding ester derivatives of 4,4'-oxydiphthalic acid and corresponding isomers; reacting said ester derivatives with a polyamine in a suitable solvent at a temperature ranging from about ambient temperature to about 50° C.; and removing the solvent at least partially to obtain the polyimide foam precursor.
Claim 3
Dependent Claim
21 words
The method according to claim 1 wherein said C 1 -C 7 -alcohol and mixtures thereof are used as a solvent.
Claim 4
Dependent Claim
19 words
The method according to claim 2 wherein the reaction is carried out at reflux temperatures until reaction is complete.
Claim 5
Dependent Claim
12 words
The method according to claim 1 wherein said polyamine is a diamine.
Claim 6
Dependent Claim
20 words
The method according to claim 4 wherein substantially equimolar quantities of 4,4'-oxydiphthalic anhydride and corresponding isomers and diamine are used.
Claim 7
Dependent Claim
30 words
The method according to claim 1 wherein said polyamine is selected from the group consisting of p- and m-phenylene diamines, methylene dianilines, oxydianilines, biphenyle diamines, toluene diamine and mixtures thereof.
Claim 8
Dependent Claim
45 words
The method according to claim 1 including the further step of adding to the solution of said precursor in said solvent a suitable quantity of an additive selected from the group consisting of surfactants, fillers, finely divided reinforcing materials, ultraviolet absorbers, hardeners and mixtures thereof.
Claim 9
Dependent Claim
26 words
The method according to claim 1 wherein said precursor is dried to a thick liquid, then cooled to room temperature, whereupon a solid mass is produced.
Claim 10
Dependent Claim
16 words
The method according to claim 1 wherein said precursor is dried to a finally divided powder.
Claim 11
Dependent Claim
9 words
A polyimide foam precursor obtained according to claim 1.
Claim 12
Dependent Claim
65 words
The method of making a resilient, high specific tensile strength, low density, cured, white coloured polyimide foam product which comprises the steps of: heating the polyimide foam precursor according to claim 10 to a temperature sufficient to cause spontaneous foaming; and heating the resulting foam to a temperature of from about 250° to 300° C. for a period sufficient to substantially fully cure the polyimide.
Claim 13
Dependent Claim
9 words
The polyimide foam product obtained according to claim 11.
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) | 1993-12-24 | 1994-06-25 | 1994-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-24 | 1998-06-25 | 1998-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-24 | 2002-06-25 | 2002-12-25 | $7700.00 | Window Closed / Lapsed |