US4090010A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water vapor permeable microporous sheet materials and their method of manufacture
Assignee: Porvair PLC
•
Filing: 1973-06-11
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Granted: 1978-05-16
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Expires: 1993-06-11
Abstract
Abstract There is disclosed a process in which both non-solvent e.g., water and filler particles e.g., microscopic sodium chloride are added in certain proportions to a polymer solution e.g., polyurethane in dimethylformamide preferably at elevated temperature and coagulated by immersion in non-solvent. This results in a more rapid coagulation time than when solvent or filler alone are used and also results in a microporous product of improved properties and novel pore structure.
Inventors
- 👤 Eric Albert Warwicker
- 👤 David Price
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:29
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28; D; D06; D06N; D06N3/00; D06N3/0043; D06N3/0052; C08J2375/00; Y; Y10; Y10S; Y10S428/00; Y10S428/904; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249978; Y10T428/249979
Claims Analysis
Total Claims: 0
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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) | 1981-05-15 | 1981-11-14 | 1982-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-15 | 1985-11-14 | 1986-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-15 | 1989-11-14 | 1990-05-16 | $7700.00 | Window Closed / Lapsed |