Patent US3173891A successfully refreshed from Google Patents.
US3173891A
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Polycarbonate process
Assignee: Union Carbide Corp
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Filing: 1960-10-10
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Granted: 1965-03-16
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Expires: 1980-10-10
Abstract
No abstract record available.
Inventors
- 👤 John S Fry
- 👤 Wynstra John
- 👤 Wendell W Moyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:38
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/20; C08G64/22; C08G64/24
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
72 words
IN A PROCESS FOR PREPARING A SUBSTANTIALLY LINEAR, THERMOPLASTIC POLYCARBONATE RESIN WHICH INCLUDES THE STEPS OF REACTNG A DIHYDRIC PHENOL WITH PHOSGENE AND AN ALKALI METAL HYDROXIDE IN AN AMOUNT SUFFICIENT TO IMPART TO THE REACTION SYSTEM A PH VALUE BETWEEN ABOUT 10.5 AND 11.8, THE IMPROVEMENT WHICH COMPRISES CONDUCTING SAID REACTION IN CONTACT WITH A BODYING CATALYST-CHAIN GROWTH TERMINATOR COMPOSITION CONSISTING ESSENTIALLY OF P-PHENYLPHENOL AND A TRIALKYLAMINE HAVING THE GENERAL FORMULA
Claim 2
Dependent Claim
72 words
IN A PROCESS FOR PREPARING A SUBSTANTIALLY LINEAR, THERMOPLASTIC POLYCARBONATE RESIN WHICH INCLUDES THE STEPS OF REACTNG A DIHYDRIC PHENOL WITH PHOSGENE AND AN ALKALI METAL HYDROXIDE IN AN AMOUNT SUFFICIENT TO IMPART TO THE REACTION SYSTEM A PH VALUE BETWEEN ABOUT 10.5 AND 11.8, THE IMPROVEMENT WHICH COMPRISES CONDUCTING SAID REACTION IN CONTACT WITH A BODYING CATALYST-CHAIN GROWTH TERMINATOR COMPOSITION CONSISTING ESSENTIALLY OF P-PHENYLPHENOL AND A TRIALKYLAMINE HAVING THE GENERAL FORMULA
References Cited (Backward Citations)
US2970131A
Cited
US2964797A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-03-15 | 1968-09-14 | 1969-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-03-15 | 1972-09-14 | 1973-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-03-15 | 1976-09-14 | 1977-03-16 | $7700.00 | Window Closed / Lapsed |