Patent US3663538A successfully refreshed from Google Patents.
US3663538A
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Cationic derivatives of 4,4' - bis-(s-triazinylamino)-stilbene -2,2'-disulfonic acid,process for the preparation thereof and application as optical brighteners
Assignee: Hoechst AG
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Filing: 1969-07-07
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Granted: 1972-05-16
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Expires: 1989-07-07
Abstract
Abstract CATIONIC COMPOUNDS OF THE 4,4'' - BIS (S - TRIAZINYLAMINO) - SILBENE - 2,2'' / DISULFONIC ACID SERIES ARE USEFUL AS OPTICAL BRIGHTENERS FOR FIBROUS MATERIALS, ESPECIALLY CELLULOSE MATERIALS. THESE BRIGHTENERS ARE COMPATIBLE WITH CATIONIC AUXILIARIES AND OPERATIVE WHEN WORKING AT LOW PH VALUES AND THUS CAPABLE OF APPLICATION TOGETHER WITH CATION-ACTIVE LAUNDRY REFINING AGENTS OR CREASE-RESISTANT FINISHING AGENTS. THEY ARE, FURTHERMORE, USEFUL FOR BRIGHTENING PAPER PULPS OR PAPER COATINGS.
Inventors
- 👤 Karl Heinz Lebkucher
- 👤 Ehrenfried Nischwitz
- 👤 Erich Schinzel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:16
CPC Classifications
C; C07; C07D; C07D251/00; C07D251/02; C07D251/12; C07D251/26; C07D251/40; C07D251/54; C07D251/68; C11; C11D; C11D1/00; D; D06; D06L; D06L4/00; D06L4/60
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) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |