Patent US1146615A successfully refreshed from Google Patents.
US4522753A
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US
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Method for preserving porosity in porous materials
Assignee: Massachusetts Institute of Technology
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Filing: 1981-07-29
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Granted: 1985-06-11
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Expires: 2001-07-29
Abstract
Abstract A method for preserving the porosity of porous materials is disclosed. In this method, the porous material is subjected to elevated temperature and vacuum conditions to thereby produce a dimensionally-stable, non-collapsible porous material.
Inventors
- 👤 Ioannis V. Yannas
- 👤 John F. Burke
- 👤 Peter J. Stasikelis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 08:09
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28; A; A61; A61F; A61F13/00; A61F13/01; A61F13/01008; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/425; A61L17/00; A61L17/06; A61L17/08; A61L27/00; A61L27/14; A61L27/22; A61L27/24; A61F2013/00089; A61F2013/00246; A61F2013/00255; A61F2013/00361; A61F2013/00727; A61F2013/00731; A61F2013/0074; A61F2013/00855; A61F2013/00863; A61F2310/00; A61F2310/00005; A61F2310/00365; C08J2201/00; C08J2201/04; C08J2201/048; C08J2389/00; Y; Y10; Y10S; Y10S602/00; Y10S602/90
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
138 words
A method of producing dimensionally-stable, non-collapsible highly porous foams based upon insoluble protein-based material, comprising: a. forming a liquid dispersion of said insoluble protein-based material; b. quickly freezing said dispersion to form frozen liquid particles; c. subliming said frozen liquid particles to produce a highly porous foam; d. subjecting said highly porous foam to an elevated temperature of from about 80° C. to about 180° C. and vacuum of from about 1 mtorr to just below atmospheric pressure, said temperature and vacuum conditions being sufficient to stabilize said highly porous foam so that its porosity is preserved when it is contacted with a liquid solution of a chemical crosslinking agent, and, e. subjecting said stabilized highly porous foam to a liquid solution of a chemical crosslinking agent so as to produce a dimensionally-stable, non-collapsible highly porous foam material.
Claim 2
Independent Claim
138 words
A method of producing dimensionally-stable, non-collapsible highly porous foams based upon insoluble protein-based material, comprising: a. forming a liquid dispersion of said insoluble protein-based material; b. quickly freezing said dispersion to form frozen liquid particles; c. subliming said frozen liquid particles to produce a highly porous foam; d. subjecting said highly porous foam to an elevated temperature of from about 80° C. to about 180° C. and vacuum of from about 1 mtorr to just below atmospheric pressure, said temperature and vacuum conditions being sufficient to stabilize said highly porous foam so that its porosity is preserved when it is contacted with a liquid solution of a chemical crosslinking agent, and, e. subjecting said stabilized highly porous foam to a liquid solution of a chemical crosslinking agent so as to produce a dimensionally-stable, non-collapsible highly porous foam material.
Claim 3
Dependent Claim
13 words
A method of claim 1 wherein said liquid dispersion comprises an aqueous dispersion.
Claim 4
Dependent Claim
16 words
A method of claim 2 wherein said insoluble protein-based material comprises a crosslinked collagen-mucopoly-saccharide composite material.
Claim 5
Dependent Claim
13 words
A method of claim 2 wherein said insoluble protein-based material comprises ground leather.
Claim 6
Dependent Claim
19 words
A method of claim 3 wherein said highly porous foam comprises a foam of greater than about 95% porosity.
Claim 7
Dependent Claim
12 words
A highly porous foam material produced by the method of claim 1.
Claim 8
Dependent Claim
12 words
A highly porous foam material produced by the method of claim 5.
Claim 9
Dependent Claim
110 words
In the production of a multi-layer membrane having a first layer formed from a protein-based polymer and a second layer comprising a moisture transmission control layer, the improvement wherein said first layer comprises a highly porous foam material based upon insoluble protein-based material having a porosity of greater than about 95% which has been subjected to an elevated temperature of from about 80° C. to about 180° C. and vacuum of from about 1 mtorr to just below atmospheric pressure in order to preserve its porosity and subsequently contacted with an aqueous solution of a chemical crosslinking agent to to cause said highly porous foam to become dimensionally-stable and non-collapsible.
Claim 10
Dependent Claim
110 words
In the production of a multi-layer membrane having a first layer formed from a protein-based polymer and a second layer comprising a moisture transmission control layer, the improvement wherein said first layer comprises a highly porous foam material based upon insoluble protein-based material having a porosity of greater than about 95% which has been subjected to an elevated temperature of from about 80° C. to about 180° C. and vacuum of from about 1 mtorr to just below atmospheric pressure in order to preserve its porosity and subsequently contacted with an aqueous solution of a chemical crosslinking agent to to cause said highly porous foam to become dimensionally-stable and non-collapsible.
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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) | 1988-06-10 | 1988-12-10 | 1989-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-10 | 1992-12-10 | 1993-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-10 | 1996-12-10 | 1997-06-11 | $7700.00 | Window Closed / Lapsed |