Patent US3567813A successfully refreshed from Google Patents.
US3567813A
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Process for preparing color and melt viscosity stable polycarbonate resins
Assignee: General Electric Co
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Filing: 1968-07-11
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Granted: 1971-03-02
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Expires: 1988-07-11
Abstract
Abstract A PROCESS FOR PREPARING AN AROMATIC CARBONATE POLYMER HAVING EXCELLENT RESISTANCE TO THERMAL DISCOLORATION AND THERMAL DEGRADATION, WHICH PROCESS INVOLVES INCORPORATING 0.1-5.0 WEIGHT PERCENT OF WATER, BASED ON THE WEIGHT OF THE TOTAL COMPOSITION WITH THE AROMATIC CARBONATE POLYMER, AND THEN EXTRUDING THE MIXTURE THROUGH A HEATED, VACUUM VENTED EXTRUDER. A VACUUM IS APPLIED TO THE MIXTURE WHILE IN THE MOLTEN STATE.
Inventors
- 👤 John J Keane
- 👤 John M Tome
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 02:31
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/40; B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/50; B29C48/76; B29C48/03; B29C48/04; B29C48/05; B29C48/07; B29C48/08; B29C48/09; B29C48/10
Claims Analysis
Total Claims: 0
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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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |