Patent US2639221A successfully refreshed from Google Patents.
US2639221A
Expired / Lapsed
US
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Noncaking sodium and potassium hydroxide for photographic developer powders
Assignee: Eastman Kodak Co
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Filing: 1952-06-26
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Granted: 1953-05-19
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Expires: 1972-06-26
Abstract
No abstract record available.
Inventors
- 👤 Richard W Henn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:34
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/264; G03C5/265; C; C01; C01D; C01D1/00; C01D1/04; C01D1/44
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
20 words
THE METHOD OF REDUCING THE HYDROSCOPIC PROPERTIES OF SODIUM AND POTASSIUM HYDROXIDE WHICH COMPRISES COATING THE HYDROXIDE WITH PHTHALIC ANHYDRIDE.
Claim 2
Independent Claim
20 words
THE METHOD OF REDUCING THE HYDROSCOPIC PROPERTIES OF SODIUM AND POTASSIUM HYDROXIDE WHICH COMPRISES COATING THE HYDROXIDE WITH PHTHALIC ANHYDRIDE.
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) | 1956-05-18 | 1956-11-17 | 1957-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-05-18 | 1960-11-17 | 1961-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-05-18 | 1964-11-17 | 1965-05-19 | $7700.00 | Window Closed / Lapsed |