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Patent US3684774A successfully refreshed from Google Patents.
US3684774A
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Hydantoins and polyhydantoins containing carboxylic acid functions
Assignee: Bayer AG
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Filing: 1970-01-28
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Granted: 1972-08-15
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Expires: 1990-01-28
Abstract
Abstract Hydantoin oligomers and polymers are produced by reacting polyglycine esters with an isocyanate of the formula OCN - R'''''' (CO - Z)n, wherein R'''''' is a hydrocarbon radical, Z is an alkoxy or aroxy radical and n is an integer from 1 to 4. In this reaction di- or polyisocyanates may be used additionally.
Inventors
- 👤 Rudolf Merten
- 👤 Gerhard Dieter Wolf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:37
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/0605; C08G73/0616; C08G18/00; C08G18/06; C08G18/28; C08G18/30; C08G18/38; C08G18/3819; C08G18/3821
Claims Analysis
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |