US5422377A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microporous polymer films and methods of their production
Assignee: National Technology and Engineering Solutions of Sandia LLC
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Filing: 1994-04-06
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Granted: 1995-06-06
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Expires: 2014-04-06
Abstract
Abstract A process for producing thin microporous polymeric films for a variety of uses. The process utilizes a dense gas (liquified gas or supercritical fluid) selected to combine with a solvent-containing polymeric film so that the solvent is dissolved in the dense gas, the polymer is substantially insoluble in the dense gas, and two phases are formed. A microporous film is obtained by removal of a dense gas-solvent phase.
Inventors
- 👤 James H. Aubert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:08
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28; B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0023; B01D67/003; B01D2323/00; B01D2323/10; B01D2323/219; B01D2323/225; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/54
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
122 words
Process for preparing a thin microporous foam film, the process comprising: (a) forming a film of a solution, said solution comprising an organic polymer, selected from the polymers having glass transition or crystallization temperature above about 20° C., dissolved in a first solvent; (b) contacting, under a predetermined pressure, said film with a foam-forming agent which is a dense gas that is a solvent for said first solvent and wherein said organic polymer is substantially insoluble; (c) allowing the film to separate into two phases: a polymer-rich phase and a solvent-rich phase comprising the first solvent and the foam-forming agent; and (d) obtaining a microporous foam film from the polymer-rich phase by modifying temperature or pressure conditions to remove the solvent-rich phase.
Claim 2
Dependent Claim
122 words
Process for preparing a thin microporous foam film, the process comprising: (a) forming a film of a solution, said solution comprising an organic polymer, selected from the polymers having glass transition or crystallization temperature above about 20° C., dissolved in a first solvent; (b) contacting, under a predetermined pressure, said film with a foam-forming agent which is a dense gas that is a solvent for said first solvent and wherein said organic polymer is substantially insoluble; (c) allowing the film to separate into two phases: a polymer-rich phase and a solvent-rich phase comprising the first solvent and the foam-forming agent; and (d) obtaining a microporous foam film from the polymer-rich phase by modifying temperature or pressure conditions to remove the solvent-rich phase.
Claim 3
Dependent Claim
32 words
The process of claim 1, wherein said contacting with a foam-forming agent comprises contacting with a dense gas selected from the group consisting of carbon dioxide, nitrogen, ethane, ethylene, propane, and propylene.
Claim 4
Dependent Claim
20 words
The process of claim 1, wherein said contacting under predetermined pressure comprises contacting with carbon dioxide in a supercritical state.
Claim 5
Dependent Claim
39 words
The process of claim 1, wherein said organic polymer is selected from the group consisting of polystyrene, polyurethane, polyethylene, polypropylene, poly(4-methyl-1-pentene), polyimide, polyamic acid, polylactic acid, polyglycolic acid, copolymers of lactic and glycolic acids, poly(epsilon-caprolactone), polyorthoesters, polyanhydrides, and poly(alphahydroxyesters).
Claim 6
Dependent Claim
25 words
The process of claim 1, wherein said forming of a film comprises forming a film of thickness ranging from about 1 to about 1,000 microns.
References Cited (Backward Citations)
US3852388A
Cited
US4818254A
Cited
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) | 1998-06-05 | 1998-12-05 | 1999-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-06-05 | 2002-12-05 | 2003-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-06-05 | 2006-12-05 | 2007-06-06 | $7700.00 | Window Closed / Lapsed |