US4272467A
Expired / Lapsed
US
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Method for producing an essentially gas and liquid impermeable low density, closed-cell, microcellular polyparabanic acid article
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1978-01-03
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Granted: 1981-06-09
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Expires: 1998-01-03
Abstract
Abstract Highly useful novel microcellular polymeric structures, especially films and fibers, are prepared from certain solid polymers. Aromatic polysulfones, polyimides, polyhydantoins, polyamides and polyparabanic acid are the preferred ones for the novel structures of the invention.
Inventors
- 👤 Burnett H. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:01
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28; B; B29; B29C; B29C67/00; B29C67/20; B29C67/202; C08J2201/00; C08J2201/04; C08J2201/054; C08J2201/0542; C08J2201/0544
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
107 words
A method of producing an essentially gas and liquid impermeable, low density, closed-celled, microcellular article of polyparabanic acid which comprises in combination the steps of: (a) forming a polymer solution of polyparabanic acid and a dipolar, aprotic solvent; (b) casting said polymer solution onto a suitable surface to form an intermediate stage structure in any suitable prearranged configuration or extruding a fiber; (c) exposing said resulting structure or fiber to a non-solvent atmosphere of high humidity thereby precipitating said polymer in the presence of the non-solvent atmosphere; (d) drying said precipitated polymer thereby forming microcellular polyparabanic acid; and (e) recovering said shaped microcellular article of polyparabanic acid.
Claim 2
Independent Claim
107 words
A method of producing an essentially gas and liquid impermeable, low density, closed-celled, microcellular article of polyparabanic acid which comprises in combination the steps of: (a) forming a polymer solution of polyparabanic acid and a dipolar, aprotic solvent; (b) casting said polymer solution onto a suitable surface to form an intermediate stage structure in any suitable prearranged configuration or extruding a fiber; (c) exposing said resulting structure or fiber to a non-solvent atmosphere of high humidity thereby precipitating said polymer in the presence of the non-solvent atmosphere; (d) drying said precipitated polymer thereby forming microcellular polyparabanic acid; and (e) recovering said shaped microcellular article of polyparabanic acid.
Claim 3
Dependent Claim
16 words
The method according to claim 1 wherein the non-solvent is water and the solvent is dimethylformamide.
Claim 4
Dependent Claim
14 words
The method according to claim 1 wherein said polymer is an aromatic polyparabanic acid.
Claim 5
Dependent Claim
13 words
The method according to claim 3 wherein said aromatic polyparabanic acid is poly[1,4-phenylenemethylene-1,4-phenylene-1,3-(imidazolidine-2,4,5-trione)].
Claim 6
Independent Claim
110 words
A method of producing an essentially gas and liquid impermeable, low density, closed-celled, microcellular article of polyparabanic acid which comprises in combination the steps of: (a) forming a polymer solution of polyparabanic acid and a dipolar, aprotic solvent; (b) casting said polymer solution onto a suitable surface to form an intermediate stage structure in any suitable prearranged configuration or extruding a fiber; (c) partially drying the casted polymer solution; (d) exposing said resulting structure or fiber to a non-solvent thereby precipitating said polymer in the presence of said non solvent; (e) drying said precipitated polymer thereby forming microcellular polyparabanic acid; and (f) recovering said shaped microcellular article of polyparabanic acid.
Claim 7
Independent Claim
110 words
A method of producing an essentially gas and liquid impermeable, low density, closed-celled, microcellular article of polyparabanic acid which comprises in combination the steps of: (a) forming a polymer solution of polyparabanic acid and a dipolar, aprotic solvent; (b) casting said polymer solution onto a suitable surface to form an intermediate stage structure in any suitable prearranged configuration or extruding a fiber; (c) partially drying the casted polymer solution; (d) exposing said resulting structure or fiber to a non-solvent thereby precipitating said polymer in the presence of said non solvent; (e) drying said precipitated polymer thereby forming microcellular polyparabanic acid; and (f) recovering said shaped microcellular article of polyparabanic acid.
Claim 8
Dependent Claim
11 words
A method according to claim 5 wherein said non-solvent is water.
Claim 9
Dependent Claim
11 words
A method according to claim 5 wherein said solvent is dimethylformamide.
Claim 10
Dependent Claim
15 words
A method according to claim 5 wherein said polyparabanic acid is an aromatic polyparabanic acid.
Claim 11
Dependent Claim
13 words
The method according to claim 8 wherein said aromatic polyparabanic acid is poly[1,4-phenylenemethylene-1,4-phenylene-1,3-(imidazolidine-2,4,5-trione)].
Claim 12
Dependent Claim
26 words
A method according to claim 5 wherein said suitable surface is a surface to which it is intended that the resulting article will become permanently bonded.
Claim 13
Dependent Claim
11 words
A method according to claim 10 wherein said substrate is metallic.
Claim 14
Dependent Claim
11 words
A method according to claim 10 wherein said substrate is copper.
Claim 15
Dependent Claim
11 words
A method according to claim 10 wherein the substrate is glass.
Claim 16
Dependent Claim
11 words
A method according to claim 10 wherein the substrate is ceramic.
Claim 17
Dependent Claim
13 words
A method according to claim 10 wherein said substrate is a porous article.
Claim 18
Dependent Claim
12 words
A method according to claim 5 wherein said article is a film.
Claim 19
Dependent Claim
19 words
A method according to claim 16 wherein said film is from about 1 mil to about 20 mils thick.
Claim 20
Dependent Claim
22 words
A method according to claim 16 wherein the cell diameters are in the range from about 0.1 micron to about 10 microns.
Claim 21
Dependent Claim
24 words
A method in accordance with claim 18 wherein the cell diameters are in the range of from about 0.1 micron to about 5 microns.
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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) | 1984-06-08 | 1984-12-08 | 1985-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-08 | 1988-12-08 | 1989-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-08 | 1992-12-08 | 1993-06-09 | $7700.00 | Window Closed / Lapsed |