US4020230A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microporous polyethylene hollow fibers and process of preparing them
Assignee: Dow Chemical Co
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Filing: 1975-10-03
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Granted: 1977-04-26
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Expires: 1995-10-03
Abstract
Abstract Normally hydrophobic, polyethylene hollow fibers having contiguous microporosity are prepared by extruding a heated solution of a polyethylene and an ester from a hollow fiber spinnerette, simultaneously cooling and drawing the forming fibers to a ratio of up to 40 to 1, drawing the gelled fibers to an overall ratio of from about 1.5/1 to 800/1 and then removing the ester. The maximum pore radius ranges up to about 50A, and the fibers have gas permeabilities approaching 10 - 2 cc (STP) per cm 2 per second per cm. Hg. transmembrane pressure differential. A significant increase in permeability over polyethylene hollow fibers made according to the teachings of the prior art is achieved.
Inventors
- 👤 Robert D. Mahoney
- 👤 Stephen E. Schneider
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:31
CPC Classifications
D; D01; D01D; D01D5/00; D01D5/24; B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0023; B01D67/0025; B01D67/0027; B01D67/003; B01D69/00; B01D69/08; B01D71/00; B01D71/06; B01D71/26; B01D71/261; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2973; Y10T428/2975
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
40 words
A microporous hollow fiber in which the porosity is contiguous, the O 2 gas permeability is at least 2×10.sup. -5 cc (STP) per cm 2 per second per cm Hg. transmembrane pressure differential and said fiber consists essentially of polyethylene.
Claim 2
Dependent Claim
40 words
A microporous hollow fiber in which the porosity is contiguous, the O 2 gas permeability is at least 2×10.sup. -5 cc (STP) per cm 2 per second per cm Hg. transmembrane pressure differential and said fiber consists essentially of polyethylene.
Claim 3
Dependent Claim
30 words
A fiber of claim 1 having an oxygen gas permeability of at least 1×10.sup. -3 cc per cm 2 of membrane area per second per cm Hg. transmembrane pressure differential.
Claim 4
Dependent Claim
19 words
A fiber of claim 2 having an oxygen gas permeability, as therein defined, of at least 2×10.sup. -3 .
Claim 5
Dependent Claim
20 words
A fiber as in claim 1, of which 10 weight percent or less is derived from olefins other than ethylene.
References Cited (Backward Citations)
US3423491A
Cited
US3798185A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-25 | 1980-10-25 | 1981-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-25 | 1984-10-25 | 1985-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-25 | 1988-10-25 | 1989-04-26 | $7700.00 | Window Closed / Lapsed |