US4546115A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyimide compositions and foams and methods of making same
Assignee: IMI-TECH Corp ELK GROVE ILL A CORP OF
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Filing: 1985-02-25
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Granted: 1985-10-08
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Expires: 2005-02-25
Abstract
Abstract Methods of making modified polyimide compositions and the resulting compositions. A polyimide forming material is prepared by treating an aromatic dianhydride with an esterifying solvent, then adding a suitable diamine. In order to obtain a foam which is non-friable and resistant to repeated compressive forces, the selected diamine must contain an aliphatic moiety in the chain. This material is dried to a powder or film. A foam is produced by heating the material to reaction temperature for a period sufficient to produce a stable foam. The material melts, then spontaneously expands into a foam which becomes self supporting and cures to a resilient, flexible non-friable foam.
Inventors
- 👤 John Gagliani
- 👤 John V. Long
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:03
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/02; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1025; C08G73/1028; C08G73/1032; C08J2379/00; C08J2379/04; C08J2379/08
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
116 words
In the method of making a polyimide precursor composition suitable for use in the manufacture of non-friable polyimide foams, which comprises the steps of esterifying an aromatic dianhydride with an esterifying solvent of produce a half-ester and reacting said half-ester with a diamine to produce a polyimide precursor composition; the improvement wherein: said diamine consists of a mixture of at least one aromatic-aliphatic diamine and from 0.1 to 50 mole % of at least one aliphatic diamine; said aromatic-aliphatic diamine having the general formula: ##STR2## wherein x is a positive integer from 1 to 20; and said aliphatic diamine has the general formula: H.sub.2 N═(CH.sub.2).sub.y ═NH.sub.2 wherein y is a positive integer from 2 to 12.
Claim 2
Dependent Claim
116 words
In the method of making a polyimide precursor composition suitable for use in the manufacture of non-friable polyimide foams, which comprises the steps of esterifying an aromatic dianhydride with an esterifying solvent of produce a half-ester and reacting said half-ester with a diamine to produce a polyimide precursor composition; the improvement wherein: said diamine consists of a mixture of at least one aromatic-aliphatic diamine and from 0.1 to 50 mole % of at least one aliphatic diamine; said aromatic-aliphatic diamine having the general formula: ##STR2## wherein x is a positive integer from 1 to 20; and said aliphatic diamine has the general formula: H.sub.2 N═(CH.sub.2).sub.y ═NH.sub.2 wherein y is a positive integer from 2 to 12.
Claim 3
Dependent Claim
25 words
The improvement according to claim 1 further including the steps of drying said polyimide precursor composition and pulverizing the resulting dry material to a powder.
Claim 4
Dependent Claim
36 words
The improvement according to claim 2 further including the step of heating said powder to cause melting and foaming of said powder as the polymerization reaction is completed whereby a resilient, non-friable, flame resistant foam results.
Claim 5
Dependent Claim
35 words
The improvement according to claim 3 wherein said heating is accomplished in an oven heated to a temperature of from about 120° to 320° C. for a period of from about 10 to 60 minutes.
Claim 6
Dependent Claim
18 words
The improvement according to claim 3 wherein said heating is accomplished by exposing the powder to microwave energy.
Claim 7
Dependent Claim
40 words
The improvement according to claim 1 wherein said solvent is either an aliphatic alcohol having up to 7 carbon atoms, or an aromatic alcohol, or either alcohol with either a halogen or amino substitution, or a mixture of such alcohols.
Claim 8
Dependent Claim
21 words
The improvement according to claim 6 wherein said aromatic-aliphatic diamine is 4,4'-diamino diphenyl methane and said aliphatic diamine is 1,6-diamino hexane.
Claim 9
Dependent Claim
19 words
The improvement according to claim 1 further including the step of drying said polyimide precursor composition by spray drying.
Claim 10
Dependent Claim
16 words
The improvement according to claim 1 wherein "x" is a positive integer from 1 to 3.
Claim 11
Dependent Claim
20 words
The improvement according to claim 1 wherein the NH 2 radicals are each in the meta rather than para position.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-07 | 1989-04-08 | 1989-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-07 | 1993-04-08 | 1993-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-07 | 1997-04-08 | 1997-10-08 | $7700.00 | Window Closed / Lapsed |