US3637642A
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Process for dissolving insoluble collagen employing a mixture of an alkali metal hydroxide an alkali metal sulfate and an amine
Assignee: Nihon Hikaku KK
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Filing: 1970-03-20
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Granted: 1972-01-25
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Expires: 1990-03-20
Abstract
Abstract A PROCESS FOR DISSOLVING INSOLUBLE COLLAGEN IN AN AQUEOUS MEDIUM IN WHICH INSOLUBLE COLLAGEN IS TREATED WITH AN AQUEOUS SOLUTION CONTAINING ALKALI METAL HYDROXIDE, ALKALI METAL SULFATE AND A SMALL AMOUNT OF A LOWER PRIMARY OR SECONDARY AMINE AND THEN, AFTER DESALTING, TREATED WITH AN AICD SOLUTION OF A PH LESS THAN 4.0.
Inventors
- 👤 Tadahiko Fujii
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 19:37
CPC Classifications
C; C09; C09H; C09H3/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-24 | 1975-07-26 | 1976-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-24 | 1979-07-26 | 1980-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-24 | 1983-07-26 | 1984-01-25 | $7700.00 | Window Closed / Lapsed |