Patent US4032309A successfully refreshed from Google Patents.
US4032309A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of microporous polycarbonate resin membranes
Assignee: General Electric Co
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Filing: 1976-04-16
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Granted: 1977-06-28
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Expires: 1996-04-16
Abstract
Abstract A casting process is set forth for the preparation of microporous membranes from polycarbonate resin material. The polycarbonate resin is dissolved in an organic casting solvent to produce a solution stable at room temperature. The solution is cast as a thin film on a smooth substrate and is permitted to desolvate for at least a few seconds. Film and substrate are immersed in a bath characterized by the capabilities for swelling the polycarbonate resin, and for dissolving the first solvent, while not dissolving the polycarbonate resin. After formation of the film is initiated, the film and substrate are removed from the quenching bath and the film is either water-washed or air dried to attain the full mechanical strength thereof.
Inventors
- 👤 Robert M. Salemme
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:05
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28; B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0009; B01D67/0011; B01D67/0016; B01D67/00165; B01D71/00; B01D71/06; B01D71/50; B01D2323/00; B01D2323/12; C08J2369/00
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
170 words
A method for the preparation of porous polycarbonate resin membranes comprising the steps of: (a) preparing a casting solution at room temperature consisting of polycarbonate resin material and a casting solvent composed of one or more good solvents, said casting solution being stable at room temperature, (b) casting a layer of the casting solution so formed on a smooth, clean surface of supporting means, (c) permitting desolvation to occur for a predetermined time interval from said layer, (d) immersing said layer and supporting means in a quenching bath liquid, said quenching bath liquid having the capabilities for dissolving said casting solvent and for causing swelling of the polycarbonate resin content of said layer while being a non-solvent for the polycarbonate resin, said immersion step initiating formation of a microporous membrane by entry of the quenching bath liquid into said layer and exit of casting solvent therefrom, (e) removing said microporous membrane from said quenching bath and (f) removing the remaining casting solvent and quenching bath liquid from said microporous membrane.
Claim 2
Independent Claim
170 words
A method for the preparation of porous polycarbonate resin membranes comprising the steps of: (a) preparing a casting solution at room temperature consisting of polycarbonate resin material and a casting solvent composed of one or more good solvents, said casting solution being stable at room temperature, (b) casting a layer of the casting solution so formed on a smooth, clean surface of supporting means, (c) permitting desolvation to occur for a predetermined time interval from said layer, (d) immersing said layer and supporting means in a quenching bath liquid, said quenching bath liquid having the capabilities for dissolving said casting solvent and for causing swelling of the polycarbonate resin content of said layer while being a non-solvent for the polycarbonate resin, said immersion step initiating formation of a microporous membrane by entry of the quenching bath liquid into said layer and exit of casting solvent therefrom, (e) removing said microporous membrane from said quenching bath and (f) removing the remaining casting solvent and quenching bath liquid from said microporous membrane.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein the casting solvent is chloroform.
Claim 4
Dependent Claim
17 words
The method of claim 2 wherein the quenching bath liquid is a mixture of methanol and dimethylformamide.
Claim 5
Dependent Claim
15 words
The method of claim 3 wherein the methanol and dimethylformamide are mixed in equal volumes.
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein the quenching bath liquid is a mixture of methanol and dimethylformamide.
Claim 7
Dependent Claim
12 words
The method of claim 1 wherein the quenching bath liquid is acetone.
Claim 8
Dependent Claim
17 words
The method of claim 1 wherein the quenching bath liquid is a mixture of methanol and toluene.
Claim 9
Dependent Claim
17 words
The method of claim 1 wherein the quenching bath liquid is a mixture of methanol and dioxane.
Claim 10
Dependent Claim
23 words
The method of claim 1 wherein the remaining casting solvent and quenching bath liquid is removed from the membrane in a water bath.
Claim 11
Dependent Claim
21 words
The method of claim 1 wherein the remaining casting solvent and quenching bath liquid is removed from the membrane by evaporation.
Claim 12
Dependent Claim
13 words
The method of claim 1 wherein a non-aqueous quenching bath liquid is employed.
Claim 13
Dependent Claim
14 words
The substantially isotropic microporous polycarbonate resin membrane produced by the process of claim 1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-27 | 1980-12-27 | 1981-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-27 | 1984-12-27 | 1985-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-27 | 1988-12-27 | 1989-06-28 | $7700.00 | Window Closed / Lapsed |