US4241114A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyimides
Assignee: I M L Corp A CORP OF DE
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Filing: 1980-02-15
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Granted: 1980-12-23
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Expires: 2000-02-15
Abstract
Abstract Polyimide foams derived from mixtures of aromatic diamines and partial esters of a benzophenonetetracarboxylic acid. The precursors are converted into polyimide foams by the application of heat; and the foams are then compressed, yielding dense, rigid, and structurally strong, intumescent materials.
Inventors
- 👤 John Gagliani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:15
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/0085; C08J9/36; C08J2379/00; C08J2379/04; C08J2379/08; Y; Y10; Y10S; Y10S521/00; Y10S521/918
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
113 words
A process of making an artifact composed in part of a rigid, intumescent, polyimide foam which comprises the steps of: preparing a resinous precursor by forming a composition which is essentially a stoichiometric mixture of aromatic diamine and tetracarboxylic acid ester constituents and dispersing a filler composed of particulate solids in said composition; applying said precursor to a substrate; then heating said precursor to a temperature in the range of 210°-315° C. to produce a polyimide foam; and then heating said foam under a pressure in the range of 3-20 psig and at a temperature in the range of 230°-315° C. for a time sufficient to produce a permanent set in said foam.
Claim 2
Dependent Claim
113 words
A process of making an artifact composed in part of a rigid, intumescent, polyimide foam which comprises the steps of: preparing a resinous precursor by forming a composition which is essentially a stoichiometric mixture of aromatic diamine and tetracarboxylic acid ester constituents and dispersing a filler composed of particulate solids in said composition; applying said precursor to a substrate; then heating said precursor to a temperature in the range of 210°-315° C. to produce a polyimide foam; and then heating said foam under a pressure in the range of 3-20 psig and at a temperature in the range of 230°-315° C. for a time sufficient to produce a permanent set in said foam.
Claim 3
Dependent Claim
32 words
A process as defined in claim 1 wherein, in heating the foam under pressure, it is maintained at a temperature approximating the highest temperature reached in converting the precursor to the foam.
Claim 4
Dependent Claim
31 words
A process as defined in claim 1 in which the foam is heated under pressure in a press and in which said press is preheated prior to processing the foam therein.
Claim 5
Dependent Claim
24 words
A process as defined in claim 1 in which the foam is heated under pressure for a period ranging from 3 to 10 minutes.
Claim 6
Dependent Claim
51 words
A process as defined in claim 1 in which any tetracarboxylic acid ester present in the precursor is a C 1 -C 3 ester of 3,3', 4,4'-benzophenonetetracarboxylic acid and the diamines are selected from the group consisting of 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, meta-phenylenediamine, para-phenylenediamine, 2,6-diaminopyridine, and 3,5-diaminopyridine.
Claim 7
Dependent Claim
60 words
A process as defined in claim 1 together with the step of adding to the precursor before it is foamed from 0.1 to one part, based on the weight of the ester and diamine constituents, of a surfactant which is effective to control the pore size and/or cellular structure of the foam into which said precursor is to be converted.
Claim 8
Dependent Claim
41 words
A process as defined in claim 1 in which the tetracarboxylic acid ester constituent comprises at least one C 1 -C 3 diester of 3,3',4,4'-benzophenonetetracarboxylic acid. cm 8. A process as defined in claim 1 wherein the filler comprises graphite fibers.
Claim 9
Dependent Claim
13 words
A process as defined in claim 1 wherein the filler comprises graphite fibers.
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) | 1983-12-23 | 1984-06-23 | 1984-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-23 | 1988-06-23 | 1988-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-23 | 1992-06-23 | 1992-12-23 | $7700.00 | Window Closed / Lapsed |