US3271364A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of preparing polycarbonates
Assignee: Gevaert Photo Producten NV
•
Filing: 1962-08-27
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Granted: 1966-09-06
•
Expires: 1982-08-27
Abstract
No abstract record available.
Inventors
- 👤 Conix Andre Jan
- 👤 Dohmen Leonard Marie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:58
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/04; C08G64/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
40 words
PROCESS FOR THE PREPARATION OF POLYCARBONATES COMPRISING REACTING A DIHALOGENFORMATE OF A DIPHENOL WITH AN ALKALI METAL HYDROXIDE, SAID HYDROXIDE BEING PRESENT IN AN AMOUNT HAVING A MOLAR RATIO TO THE AMOUNT OF SAID DIHALOGENOFORMATE OF AT LEAST ABOUT 4:1.
Claim 2
Dependent Claim
40 words
PROCESS FOR THE PREPARATION OF POLYCARBONATES COMPRISING REACTING A DIHALOGENFORMATE OF A DIPHENOL WITH AN ALKALI METAL HYDROXIDE, SAID HYDROXIDE BEING PRESENT IN AN AMOUNT HAVING A MOLAR RATIO TO THE AMOUNT OF SAID DIHALOGENOFORMATE OF AT LEAST ABOUT 4:1.
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) | 1969-09-05 | 1970-03-07 | 1970-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-09-05 | 1974-03-07 | 1974-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-09-05 | 1978-03-07 | 1978-09-06 | $7700.00 | Window Closed / Lapsed |