US4506038A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Development of polyimide foams with blowing agents
Assignee: I M L Corp A CORP OF
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Filing: 1982-12-03
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Granted: 1985-03-19
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Expires: 2002-12-03
Abstract
Abstract A method of preparing a polyimide foam which includes the steps of: preparing, foaming, and curing a precursor containing at least one alkyl ester of 3,3'4,4'-benzophenonetetracarboxylic acid; a meta- or para-substituted aromatic diamine; a heterocyclic diamine; an aliphatic diamine; and a solid blowing agent. The blowing agent is added to said precursor in a concentration which is sufficient to effect at least one of the following attributes of the foam: cell size, proportion of open cells, cell density, and indentation load deflection.
Inventors
- 👤 John Gagliani
- 👤 Usman A. K. Sorathia
- 👤 Raymond Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:08
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/06; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1046; C08G73/105; C08G73/1057; C08G73/1064; C08G73/1067; C08G73/1085; C08L; C08L79/00; C08L79/04; C08L79/08; C08J2379/00; C08J2379/04; C08J2379/08
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
85 words
A method of preparing a polyimide foam which includes the steps of: preparing, foaming, and curing a solvent-free precursor consisting essentially of at least one alkyl ester of 3,3'4,4'-benzophenonetetracarboxylic acid; a meta- or para-substituted aromatic diamine; a heterocyclic diamine; an aliphatic diamine; and a solid blowing agent, said blowing agent being present in said precursor in a concentration which is sufficient to affect at least one of the following attributes of the foam: cell size, proportion of open cells, cell density, and identation load deflection.
Claim 2
Independent Claim
85 words
A method of preparing a polyimide foam which includes the steps of: preparing, foaming, and curing a solvent-free precursor consisting essentially of at least one alkyl ester of 3,3'4,4'-benzophenonetetracarboxylic acid; a meta- or para-substituted aromatic diamine; a heterocyclic diamine; an aliphatic diamine; and a solid blowing agent, said blowing agent being present in said precursor in a concentration which is sufficient to affect at least one of the following attributes of the foam: cell size, proportion of open cells, cell density, and identation load deflection.
Claim 3
Dependent Claim
39 words
A method of preparing a polyimide foam as defined in claim 1 wherein the 3,3'4,4'-benzophenonetetracarboxylic acid ester and the diamine constituents are present in said diamine, ester solution in amounts such that the imide forming functionalities are substantially equimolar.
Claim 4
Dependent Claim
47 words
A method of preparing a polyimide foam as defined in claim 1 wherein the heterocyclic and aromatic diamines are selected from the group consisting of: 2,6-diaminopyridine 3,5-diaminopyridine 3,3'-diaminodiphenyl sulfone 4,4'-diaminodiphenyl sulfone 4,4'-diaminodiphenyl sulfide 3,3'-diaminodiphenyl ether 4,4'-diaminodiphenyl ether meta-phenylene diamine para-phenylene diamine p,p'-methylene dianiline 2,6-diamino toluene 2,4-diamino toluene.
Claim 5
Dependent Claim
42 words
A method of preparing a polyimide foam as defined in claim 1 in which the diamine, ester solution contains from 0.05 to 0.3 mole of aliphatic diamine and from 0.1 to 0.3 mole of heterocyclic diamine per mole of 3,3'4,4'-benzophenonetetracarboxylic acid ester.
Claim 6
Dependent Claim
28 words
A method of preparing a polyimide foam as defined in claim 1 wherein the aliphatic diamine, in the diamine ester solution has from three to twelve carbon atoms.
Claim 7
Dependent Claim
34 words
A method of preparing a polyimide foam as defined in claim 1 wherein the aliphatic diamine in the diamine, ester solution has the formula ##STR3## where the x is on the order of 2.6.
Claim 8
Dependent Claim
38 words
A method of preparing a polyimide foam as defined in claim 1 wherein said solid blowing agent is present in said precursor in a concentration of not more than ten percent based on the weight of the precursor.
Claim 9
Dependent Claim
35 words
A method of preparing a polyimide foam as defined in claim 7 wherein said blowing agent is present in said precursor in a concentration of about 2.5 percent based on the weight of the precursor.
Claim 10
Dependent Claim
43 words
A method of preparing a polyimide foam as defined in claim 1 wherein the solid blowing agent is one of the following: toluene sulfonyl hydrazide p,p'-oxybis(benzenesulfonyl hydrazide) azodicarbonamide p-toluenesulfonyl semicarbazide hydrazole dicarboxylate sodium bicarbonate benzene sulfonyl hydrazide sodium borate boric acid benzoic acid.
Claim 11
Dependent Claim
28 words
A method of preparing a polyimide foam as defined in claim 5 wherein the aliphatic diamine is selected from the group consisting of: 1,3-diaminopropane; 1,4-diaminobutane 1,6-diaminohexane 1,8-diaminooctane 1,12-diaminododecane.
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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) | 1988-03-18 | 1988-09-17 | 1989-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-18 | 1992-09-17 | 1993-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-18 | 1996-09-17 | 1997-03-19 | $7700.00 | Window Closed / Lapsed |