US5500450A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultra-low density microcellular polymer foam and method
Assignee: ENERGY DEPARTMENT OF United States,
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Filing: 1995-04-05
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Granted: 1996-03-19
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Expires: 2015-04-05
Abstract
Abstract An ultra-low density, microcellular open-celled polymer foam and a method for making such foam. A polymer is dissolved in a heated solution consisting essentially of at least one solvent for the dissolution of the polymer in the heated solution and the phase inversion of the dissolved polymer to a liquid gel upon sufficient cooling of the heated solution. The heated solution is contained in a containment means provided with a nucleating promoting means having a relatively rough surface formed of fixed nucleating sites. The heated solution is cooled for a period of time sufficient to form a liquid gel of the polymer by phase inversion. From the gel, a porous foam having a density of less than about 12.0 mg/cm3 and open porosity provided by well interconnected strut morphology is formed.
Inventors
- 👤 Ronald F. Simandl
- 👤 John D. Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:39
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
179 words
A method for making an ultra-low density, microcellular open-celled polymer from a member selected from the group consisting of an acetate end capped polyacetal and a (4-methyl-1-pentene)polymer foam, comprising the steps of: a) dissolving a polymer in a heated solution consisting essentially of at least one solvent for the dissolution of said polymer in said heated solution and the phase inversion of said dissolved polymer to a liquid gel upon sufficient cooling of said heated solution; b) containing said heated solution including said dissolved polymer in a containment means provided with a nucleating promoting means having a relatively rough surface formed of fixed nucleating sites wherein said nucleating sites are in the range of from about 0.1 microns to 400 microns; c) cooling said heated solution in said containment means for a period of time sufficient to form said liquid gel of said polymer by phase inversion; and d) forming a porous foam from said liquid gel, said porous foam having a density of less than about 12.0 mg/cm 3 and open porosity provided by well interconnected strut morphology.
Claim 2
Independent Claim
179 words
A method for making an ultra-low density, microcellular open-celled polymer from a member selected from the group consisting of an acetate end capped polyacetal and a (4-methyl-1-pentene)polymer foam, comprising the steps of: a) dissolving a polymer in a heated solution consisting essentially of at least one solvent for the dissolution of said polymer in said heated solution and the phase inversion of said dissolved polymer to a liquid gel upon sufficient cooling of said heated solution; b) containing said heated solution including said dissolved polymer in a containment means provided with a nucleating promoting means having a relatively rough surface formed of fixed nucleating sites wherein said nucleating sites are in the range of from about 0.1 microns to 400 microns; c) cooling said heated solution in said containment means for a period of time sufficient to form said liquid gel of said polymer by phase inversion; and d) forming a porous foam from said liquid gel, said porous foam having a density of less than about 12.0 mg/cm 3 and open porosity provided by well interconnected strut morphology.
Claim 3
Dependent Claim
25 words
The method as in claim 1, wherein said at least one solvent is selected from the group consisting of naphthalene, durene, cyclohexanol, and mixtures thereof.
Claim 4
Dependent Claim
26 words
The method as in claim 2, wherein said heated solution comprises about 0.20 to 1.0 wt. % polymer and about 99.8 to 99.0 wt. % solvent.
Claim 5
Dependent Claim
25 words
The method as in claim 3, wherein said heated solution is at a temperature in the range of from about 100° C. to 160° C.
Claim 6
Dependent Claim
13 words
The method as in claim 4, wherein said containment means comprises a vessel.
Claim 7
Dependent Claim
11 words
The method as in claim 5, wherein said polymer is poly(4-methyl-1-pentene).
Claim 8
Dependent Claim
88 words
The method as in claim 6, wherein said step of forming said porous foam from said liquid gel comprises quenching said liquid gel in said vessel under a pressure of about 50 psi and a temperature of about 0° C. for a period of time sufficient to form a solid wax from said liquid gel and removing said at least one solvent from said wax by vacuum sublimation to form a porous foam having a density in the range of from about 3.25 to 4.30 mg/cm 3 .
Claim 9
Dependent Claim
19 words
The method as in claim 7, wherein said nucleating promoting means is a perforated metal liner within said vessel.
Claim 10
Dependent Claim
19 words
The method as in claim 7, wherein said nucleating promoting means is a matted paper liner within said vessel.
Claim 11
Dependent Claim
19 words
The method as in claim 7, wherein said nucleating promoting means is an abrasive paper liner within said vessel.
Claim 12
Dependent Claim
21 words
The method as in claim 7, wherein said nucleating promoting means is an aluminum oxide polishing film liner within said vessel.
Claim 13
Dependent Claim
13 words
The method as in claim 5, wherein said polymer is acetate end-capped polyacetal.
Claim 14
Dependent Claim
71 words
The method as in claim 12, wherein the step of forming said porous foam from said liquid gel comprises removing said at least one solvent from said gel by exchanging said at least one solvent with a supercritically extractable solvent therefore and extracting this last mentioned solvent with supercritical carbon dioxide to form a porous foam having a density in the range of from about 7.80 to 12.0 mg/cm 3 .
Claim 15
Dependent Claim
19 words
The method as in claim 13, wherein said nucleating promoting means is a perforated metal liner within said vessel.
Claim 16
Dependent Claim
19 words
The method as in claim 13, wherein said nucleating promoting means is a matted paper liner within said vessel.
Claim 17
Dependent Claim
19 words
The method as in claim 13, wherein said nucleating promoting means is an abrasive paper liner within said vessel.
Claim 18
Dependent Claim
21 words
The method as in claim 13, wherein said nucleating promoting means is an aluminum oxide polishing film liner within said vessel.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1999-03-19 | 1999-09-18 | 2000-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-03-19 | 2003-09-18 | 2004-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-03-19 | 2007-09-18 | 2008-03-19 | $7700.00 | Window Closed / Lapsed |