US5066684A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low density microcellular foams
Assignee: United States Department of Energy
•
Filing: 1990-06-08
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Granted: 1991-11-19
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Expires: 2010-06-08
Abstract
Abstract Disclosed is a process of producing microcellular foam which comprises the steps of: (a) selecting a multifunctional epoxy oligomer resin; (b) mixing said epoxy resin with a non-reactive diluent to form a resin-diluent mixture; (c) forming a diluent containing cross-linked epoxy gel from said resin-diluent mixture; (d) replacing said diluent with a solvent therefore; (e) replacing said solvent with liquid carbon dioxide; and (f) vaporizing off said liquid carbon dioxide under supercritical conditions, whereby a foam having a density in the range of 35-150 mg/cc and cell diameters less than about 1 mu m is produced. Also disclosed are the foams produced by the process.
Inventors
- 👤 James D. LeMay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:34
CPC Classifications
G; G21; G21B; G21B1/00; G21B1/11; G21B1/19; C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/122; C08J9/36; C08J9/365; C08J2363/00; Y; Y02; Y02E; Y02E30/00; Y02E30/10
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
87 words
A process for preparing low density foam material which comprises: (a) mixing a multifunctional epoxy oligomer resin with a non-reactive diluent to form a resin-diluent mixture; (b) forming a diluent containing cross-linked epoxy gel from said resin-diluent mixture; (c) replacing said diluent with a solvent therefore; (d) replacing said solvent with liquid carbon dioxide; and (e) vaporizing off said liquid carbon dioxide under supercritical conditions, whereby a foam having a density in the range of 35-150 mg/cc and cell diameters less than about 1 μm is produced.
Claim 2
Dependent Claim
87 words
A process for preparing low density foam material which comprises: (a) mixing a multifunctional epoxy oligomer resin with a non-reactive diluent to form a resin-diluent mixture; (b) forming a diluent containing cross-linked epoxy gel from said resin-diluent mixture; (c) replacing said diluent with a solvent therefore; (d) replacing said solvent with liquid carbon dioxide; and (e) vaporizing off said liquid carbon dioxide under supercritical conditions, whereby a foam having a density in the range of 35-150 mg/cc and cell diameters less than about 1 μm is produced.
Claim 3
Dependent Claim
22 words
The process of claim 1 wherein said diluent containing cross-linked epoxy gel is formed by cross-linking said resin-diluent mixture with a co-monomer.
Claim 4
Dependent Claim
25 words
The process of claim 1 wherein said diluent containing cross-linked epoxy gel is formed by homopolymerizing said resin-diluent mixture in the presence of a catalyst.
Claim 5
Dependent Claim
19 words
The process of claim 1 wherein said epoxy polymer has the formula: ##STR2## wherein n is at least 1.
Claim 6
Dependent Claim
24 words
The process of claim 1 wherein said non-reactive diluent is selected from the group consisting of chlorobenzene, dimethyl formamide, benzyl alcohol and mixtures thereof.
Claim 7
Dependent Claim
12 words
The process of claim 3 wherein said catalyst is a tertiary amine.
Claim 8
Dependent Claim
25 words
The process of claim 1 wherein said carbon dioxide is vaporized by heating said gel in a pressure vessel to a temperature above 31° C.
Claim 9
Dependent Claim
12 words
The process of claim 6 wherein said catalyst is benzyldimethylmine or 1,4-diazobycyclo[2.2.2]octane.
Claim 10
Dependent Claim
11 words
The process of claim 1 wherein said cross-linking co-monomer is 4,4'-diaminophenylmethane.
Claim 11
Dependent Claim
21 words
The process of claim 1 wherein said epoxy polymer of (c) is subject to a solvent exchange in a solvent therefor.
Claim 12
Dependent Claim
10 words
The process of claim 10 wherein said solvent is acetone.
Claim 13
Dependent Claim
20 words
The process of claim 1 wherein said liquid carbon dioxide is maintained under pressure at 14° C. and 900 psi.
Claim 14
Dependent Claim
18 words
The process of claim 1 wherein after step (e) the foam produced is further post-cured at elevated temperatures.
References Cited (Backward Citations)
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Cited
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Cited
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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) | 1994-11-18 | 1995-05-20 | 1995-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-18 | 1999-05-20 | 1999-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-18 | 2003-05-20 | 2003-11-19 | $7700.00 | Window Closed / Lapsed |