US3267075A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing polycarbonates
Assignee: Bayer AG
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Filing: 1962-12-20
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Granted: 1966-08-16
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Expires: 1982-12-20
Abstract
No abstract record available.
Inventors
- 👤 Schnell Hermann
- 👤 Bottenbruch Ludwig
- 👤 Lotter Hans Georg
- 👤 Schwarz Helmut
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:27
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/40
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
120 words
A PROCESS FOR REDUCING THE RESIDUAL CONTENT OF VOLATILIZABLE IMPURITIES OF A CRUDE POLYCARBONATE MIX WHICH COMPRISES HEATING A POLYCARBONATE SOLUTION OF FROM ABOUT 2 TO ABOUT 40 PERCENT BY WEIGHT OF POLYCARBONATE TO AT LEAST THE BOILING POINT OF THE SOLVENT IN SAID POLYCARBONATE SOLUTION, THEREBY VOLATILIZING A PORTION OF SAID SOLVENT, ADDING TO THE REMAINING POLYCARBONATE MIX AT LEAST ONE MATERIAL SUBSTANTIALLY CHEMICALLY INERT TO THE POLYCARBONATE MIX, AND INERT MATERIAL HAVING A BOILING POINT DIFFERENT FROM THE SOLVENT IN SAID MIX AND BELOW THE DECOMPOSITION TEMPERATURE OF THE POLYCARBONATE IN SAID MIX, HEATING THE RESULTING MIXTURE TO AT LEAST THE MELTING POINT OF THE POLYCARBONATE IN SAID CRUDE MIX AND THEREAFTER RECOVERING THE RESULTING SUBSTANTIALLY PURE POLYCARBONATE.
Claim 2
Dependent Claim
120 words
A PROCESS FOR REDUCING THE RESIDUAL CONTENT OF VOLATILIZABLE IMPURITIES OF A CRUDE POLYCARBONATE MIX WHICH COMPRISES HEATING A POLYCARBONATE SOLUTION OF FROM ABOUT 2 TO ABOUT 40 PERCENT BY WEIGHT OF POLYCARBONATE TO AT LEAST THE BOILING POINT OF THE SOLVENT IN SAID POLYCARBONATE SOLUTION, THEREBY VOLATILIZING A PORTION OF SAID SOLVENT, ADDING TO THE REMAINING POLYCARBONATE MIX AT LEAST ONE MATERIAL SUBSTANTIALLY CHEMICALLY INERT TO THE POLYCARBONATE MIX, AND INERT MATERIAL HAVING A BOILING POINT DIFFERENT FROM THE SOLVENT IN SAID MIX AND BELOW THE DECOMPOSITION TEMPERATURE OF THE POLYCARBONATE IN SAID MIX, HEATING THE RESULTING MIXTURE TO AT LEAST THE MELTING POINT OF THE POLYCARBONATE IN SAID CRUDE MIX AND THEREAFTER RECOVERING THE RESULTING SUBSTANTIALLY PURE POLYCARBONATE.
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) | 1969-08-15 | 1970-02-14 | 1970-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-08-15 | 1974-02-14 | 1974-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-08-15 | 1978-02-14 | 1978-08-16 | $7700.00 | Window Closed / Lapsed |