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US4269713A
Expired / Lapsed
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Ethylene-vinyl alcohol copolymer membrane and a method for producing the same
Assignee: Kuraray Co Ltd
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Filing: 1979-08-31
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Granted: 1981-05-26
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Expires: 1999-08-31
Abstract
Abstract There is described an ethylene-vinyl alcohol copolymer membrane comprising at least a skin layer on its surface and a porous layer supporting the skin layer. The porous layer, when the membrane is observed in the dry state with an electron microscope, contains vacuoles or voids, which present a mono- or multi-layer structure and have straight-line lengths corresponding to 20-99% of the whole thickness of the membrane. In addition, the polymer portion of the porous layer has micropores with an average pore diameter of 0.1-5 microns and the membrane has a porosity of 60-90%.
Inventors
- 👤 Shuzo Yamashita
- 👤 Syuji Kawai
- 👤 Hirokuni Tanii
- 👤 Koichi Takakura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:55
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0009; B01D67/0016; B01D67/00165; B01D69/00; B01D69/02; B01D69/08; B01D71/00; B01D71/06; B01D71/38; B01D71/381; B01D2323/00; B01D2323/12; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2973; Y10T428/2975
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
94 words
An ethylene-vinyl alcohol copolymer membrane comprising at least a skin layer on the surface thereof and a porous layer supporting said skin layer, wherein said porous layer, when said membrane is observed in the dry state with an electron microscope, comprises a plurality of vacuoles or voids, which present a mono- or multi-layer structure, with an average straight-line length corresponding to 20-99% of the whole thickness of the membrane, and the polymer portion of said porous layer comprises micropores with an average diameter of 0.1-5 microns, and said membrane has a porosity of 60-90%.
Claim 2
Dependent Claim
94 words
An ethylene-vinyl alcohol copolymer membrane comprising at least a skin layer on the surface thereof and a porous layer supporting said skin layer, wherein said porous layer, when said membrane is observed in the dry state with an electron microscope, comprises a plurality of vacuoles or voids, which present a mono- or multi-layer structure, with an average straight-line length corresponding to 20-99% of the whole thickness of the membrane, and the polymer portion of said porous layer comprises micropores with an average diameter of 0.1-5 microns, and said membrane has a porosity of 60-90%.
Claim 3
Dependent Claim
14 words
A membrane as claimed in claim 1, wherein said membrane is a flat membrane.
Claim 4
Dependent Claim
72 words
A flat membrane as claimed in claim 2, produced by a process which comprises dissolving an ethylene-vinyl alcohol copolymer in a solvent consisting essentially of at least one compound selected from the group consisting of dimethyl sulfoxide, dimethylacetamide, N-methylpyrrolidone and pyrrolidone to a polymer concentration, C, of 10-40% by weight, and coagulating the resulting solution in an aqueous coagulation bath, at a coagulation bath temperature, T°C., which satisfies the following relation: ##EQU8##
Claim 5
Dependent Claim
15 words
A membrane as claimed in claim 1, wherein said membrane is a hollow first membrane.
Claim 6
Dependent Claim
90 words
A membrane as claimed in claim 4, produced by a process which comprises dissolving an ethylene-vinyl alcohol copolymer in a solvent consisting essentially of at least one compound selected from the group consisting of dimethyl sulfoxide, dimethylacetamide, N-methylpyrrolidone and pyrrolidone, to a polymer concentration, C, of 10-40% by weight, extruding the resulting polymer solution through an annular nozzle into a coagulation bath while introducing a noncoagulating fluid through the central aperture of said nozzle, and coagulating the fiber at a coagulation bath temperature, T°C., which satisfies the following relation: ##EQU9##
Claim 7
Dependent Claim
111 words
A membrane as claimed in claim 4, produced by a process which comprises dissolving an ethylene-vinyl alcohol copolymer in a solvent consisting essentially of at least one compound selected from the group consisting of dimethyl sulfoxide, dimethylacetamide, N-methylpyrrolidone and pyrrolidone to a polymer concentration, C, of 15-40% by weight, extruding the resulting polymer solution through an annular nozzle into a gaseous atmosphere while introducing a coagulating liquid through the central aperture of said nozzle, passing the spun fiber through said gaseous atmosphere so that the fiber is subjected to 0.5-20 times of drafting, and coagulating the same in a coagulation bath at a coagulation temperature, T°C., satisfying the following relation: ##EQU10##
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) | 1984-05-25 | 1984-11-24 | 1985-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-25 | 1988-11-24 | 1989-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-25 | 1992-11-24 | 1993-05-26 | $7700.00 | Window Closed / Lapsed |