US4355120A
Expired / Lapsed
US
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Polyimide foams
Assignee: I M L Corp A CORP OF
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Filing: 1981-12-07
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Granted: 1982-10-19
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Expires: 2001-12-07
Abstract
Abstract Copolyimide foams derived from a diester of 3,3',4,4'-benzophenonetetracarboxylic acid, an aromatic diamine, and a heterocyclic diamine. A molar concentration of the heterocyclic diamine approaching but not exceeding 0.42 is employed. This results in a flexible foam with a homogeneous cellular structure and a reduced compression set loss.
Inventors
- 👤 John Gagliani
- 👤 Raymond Lee
- 👤 Usman A. K. Sorathia
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:04
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/02; C08J3/00; C08J3/28; C08L; C08L79/00; C08L79/04; C08L79/08; C08J2379/00; C08J2379/04; C08J2379/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
73 words
A polyimide foam precursor which is a resinoid obtained by combining at least one alkyl ester of 3,3',4,4'-benzophenonetetracarboxylic acid; a meta- or para-substituted aromatic diamine which is free of aliphatic moieties; and a heterocyclic diamine, said ester(s) and said diamines being present in concentrations such that the imide forming functionalities are substantially equimolar, and the molar ratio of heterocylic diamine to tetracarboxylic acid diester being in the range of about 0.4-0.42 to 1.0.
Claim 2
Dependent Claim
73 words
A polyimide foam precursor which is a resinoid obtained by combining at least one alkyl ester of 3,3',4,4'-benzophenonetetracarboxylic acid; a meta- or para-substituted aromatic diamine which is free of aliphatic moieties; and a heterocyclic diamine, said ester(s) and said diamines being present in concentrations such that the imide forming functionalities are substantially equimolar, and the molar ratio of heterocylic diamine to tetracarboxylic acid diester being in the range of about 0.4-0.42 to 1.0.
Claim 3
Dependent Claim
30 words
A polyimide foam precursor as defined in either of the preceding claims 1 or 2 which also contains from about 0.00625 to about 0.05 weight percent of an effective surfactant.
Claim 4
Dependent Claim
29 words
A polyimide foam precursor as defined in either of the preceding claims 1 or 2 in which the heterocyclic diamine is 2,6-diaminopyridine and the aromatic diamine is p,p'-methylene dianiline.
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) | 1985-10-18 | 1986-04-19 | 1986-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-10-18 | 1990-04-19 | 1990-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-10-18 | 1994-04-19 | 1994-10-19 | $7700.00 | Window Closed / Lapsed |