US3791997A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water vapor permeable flexible sheet materials
Assignee: Porvair PLC
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Filing: 1970-11-19
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Granted: 1974-02-12
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Expires: 1990-11-19
Abstract
Abstract IN A METHOD OF MAKING WATER VAPOR PERMEABLE FLEXIBLE SHEET MATERIALS, WHICH FIND USES AS REPLACEMENTS FOR LEATHER, WHICH INCLUDED TWO SUPERIMPOSED LAYERS, A SUBSTRATE LAYER IS FORMED OF A LAYER OF A MIXTURE OF POWDERED REMOVABLE FILTER DISPENSED THROUGH A POLYMER SOLUTION IN WHICH ADHERES TO A TEMPORARY BACKER, AND BEFORE THE SOLVENT IS REMOVED A TOP COAT OF A SIMILAR MIXTURE IS FORMED ON THE SUBSTRATE LAYER, THE POLYMER IS COAGULATED AND THE FILLER LEACHED OUT FROM BOTH LAYERS BY SUITABLE LIQUID TREATMENT, THE TWO SUPERIMPOSED LAYERS ARE DRIED AND STRIPPED AS ONE LAYER FROM THE SUPPORTS.
Inventors
- 👤 G Hathorn
- 👤 V Cunningham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:29
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/26; Y; Y10; Y10S; Y10S264/00; Y10S264/13; Y10S264/62; Y10S264/77; Y10S428/00; Y10S428/904; Y10S521/00; Y10S521/918
Claims Analysis
Total Claims: 0
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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) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |