US3823212A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of collagen fiber fabrics in the form of felt-like membranes or sponge-like layers
Assignee: Carl Freudenberg KG
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Filing: 1971-05-28
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Granted: 1974-07-09
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Expires: 1991-05-28
Abstract
Abstract PRODUCTION OF FELT-LIKE MEMBRANE OR SPONGE-LIKE LAYERS OF COLLAGEN FIBERS BY DECOMPSING SKIN/OR TENDONS OR OTHER ANIMAL CONNECTIVE TISSUES RICH IN COLLAGEN UNDER ALKALINE AND/OR ACID CONDITIONS; MECHANICALLY COMMINUTING THE DECOMPOSITION PRODUCT; SUSPENDING THE COMMINUTED COLLAGEN STOCK OBTAIN IN WATER TO FORM A HOMOGENEOUS COLLAGEN SLURRY; ADDING A TANNING OR CROSS-LINKING AGENT TO THE SLURRY; FOAMING THE COLLAGEN SLURRY; FREEZING THE FOAMED COLLAGEN SLURRY SO OBTAINED IN THE FORM OF A LAYER AT -5 TO -40* C.; INCUBATING THE FROZEN SLURRY FOR 1 TO 30 DAYS; AND THEN FREEING THE BULK OF THE WATER THEREFROM BY SIMPLE MECHANICAL SQUEEZING AND.OR EVAPORATIVE DRYING.
Inventors
- 👤 M Chvapil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 16:25
CPC Classifications
A; A61; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/44; A61L15/22; A61L15/32; A61L15/325; A61L15/40; A61L15/425; C; C08; C08L; C08L89/00; C08L89/04; C08L89/06; A61L2300/00; A61L2300/40; A61L2300/402; A61L2300/404; A61L2300/406; A61L2300/418; A61L2300/42; Y; Y10; Y10S; Y10S128/00; Y10S128/08
Claims Analysis
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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) | 1977-07-08 | 1978-01-07 | 1978-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-08 | 1982-01-07 | 1982-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-08 | 1986-01-07 | 1986-07-09 | $7700.00 | Window Closed / Lapsed |