Patent US3248416A successfully refreshed from Google Patents.
US3248416A
Expired / Lapsed
US
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Method of preparing high molecular weight polycarbonates
Assignee: PPG Industries Inc
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Filing: 1963-01-16
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Granted: 1966-04-26
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Expires: 1983-01-16
Abstract
No abstract record available.
Inventors
- 👤 Henry C Stevens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:18
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/40; C08G18/42; C08G18/44; C08G64/00; C08G64/20; C08G64/30
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
110 words
A METHOD OF PREPARING A HIGH MOLECULAR WEIGHT POLYCARBONATE WHICH COMPRISES HEATING WITH BASE CATALYST PRESENT A MIXTURE OF A CYCLIC CARBONATE HAVING 3 TO 6 CARBON ATOMS SELECTED FROM THE GROUP CONSISTING OF ALKYLCENE AND VINYLENE CARBONATES AND AN ALKYLENE 1,2 EPOXIDE CONTAINING UP TO 6 CARBON ATOMS WITH FROM 0.01 TO 0.2 MOLE OF A DIHYDRIC ALCOHOL OF THE FORMULA HO-R-OH WHEREIN R IS A RADICAL SELECTED FROM THE GROUP CONSISTING OF ALKYLENE AND POLYALKYTNE ETHER RADICALS HAVING UP TO 10 CARBON ATOMS AND UP TO 4 ETHER LINKAGES PER MOLE OF CARBONATE TO ABOVE 100*C., AND BELOW A TEMPERATURE AT WHICH SUBSTANTIAL RUPTURE OF THE POLYCARBONATE OCCURS.
Claim 2
Independent Claim
110 words
A METHOD OF PREPARING A HIGH MOLECULAR WEIGHT POLYCARBONATE WHICH COMPRISES HEATING WITH BASE CATALYST PRESENT A MIXTURE OF A CYCLIC CARBONATE HAVING 3 TO 6 CARBON ATOMS SELECTED FROM THE GROUP CONSISTING OF ALKYLCENE AND VINYLENE CARBONATES AND AN ALKYLENE 1,2 EPOXIDE CONTAINING UP TO 6 CARBON ATOMS WITH FROM 0.01 TO 0.2 MOLE OF A DIHYDRIC ALCOHOL OF THE FORMULA HO-R-OH WHEREIN R IS A RADICAL SELECTED FROM THE GROUP CONSISTING OF ALKYLENE AND POLYALKYTNE ETHER RADICALS HAVING UP TO 10 CARBON ATOMS AND UP TO 4 ETHER LINKAGES PER MOLE OF CARBONATE TO ABOVE 100*C., AND BELOW A TEMPERATURE AT WHICH SUBSTANTIAL RUPTURE OF THE POLYCARBONATE OCCURS.
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) | 1969-04-25 | 1969-10-25 | 1970-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-04-25 | 1973-10-25 | 1974-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-04-25 | 1977-10-25 | 1978-04-26 | $7700.00 | Window Closed / Lapsed |