US3622526A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water vapor permeable porous sheet structures and process therefor
Assignee: Bayer AG
•
Filing: 1967-12-07
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Granted: 1971-11-23
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Expires: 1987-12-07
Abstract
Abstract Water-permeable porous sheet structures are prepared by adding an inorganic filler which has a shaken volume of from 3 to 20 cc. per gram into a solution of a polyurethane urea and then treating the polyurethane-urea solution with a nonsolvent which is miscible with the solvent and shaping the solution to form a water-permeable porous sheet structure with removal of the solvent and the nonsolvent.
Inventors
- 👤 Bruno Zorn
- 👤 Harald Oertel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 16:14
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28; B; B32; B32B; B32B27/00; C08K; C08K3/00; C08K3/01; C08K3/013; D; D06; D06N; D06N3/00; D06N3/0056; D06N3/0063; C08J2375/00; C08J2375/04; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
23 words
The process of claim 1 wherein the finely divided inorganic filler has a shaken volume of from 6 to 20 cc. per gram.
Claim 2
Dependent Claim
20 words
The process of claim 1 wherein said solution of film-forming polyurethane-urea is prepared in dimethyl-formamide and said nonsolvent is water.
Claim 3
Dependent Claim
20 words
The process of claim 1 wherein said inorganic filler is silicic acid, calcium silicate, aluminum silicate, activated charcoal, or kieselguhr.
Claim 4
Dependent Claim
9 words
Microporous sheet structures prepared by the process of claim
Claim 5
Dependent Claim
93 words
The microporous sheet structure of claim 5 having a melting point on the Kofler bench of at least 150* C., a tensile strength of at least about 100 kg./cm.2, an elongation at break of at least 200 percent, an elastic modulus of at least 1 kg./cm.2 on the first elongation by 20 percent and at least 5 kg./cm.2 on elongation by 100 percent, and a molecular weight which corresponds to an inherent viscosity of at least 0.5 when 1 gram of the polymer is dissolved at 20* C. in 100 ml. of hexamethylphosphoramide.
References Cited (Backward Citations)
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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) | 1974-11-22 | 1975-05-24 | 1975-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-22 | 1979-05-24 | 1979-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-22 | 1983-05-24 | 1983-11-23 | $7700.00 | Window Closed / Lapsed |