US4873314A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of polycarbonate solutions
Assignee: Bayer AG
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Filing: 1988-02-18
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Granted: 1989-10-10
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Expires: 2008-02-18
Abstract
Abstract The invention relates to a process for the production of solutions of polycarbonates in organic inert solvents which is characterized in that from 2.5 ppm to 100 ppm phosphorous acid, based on the weight of the diphenol used for polycarbonate production, are added to the emulsion of the two phases obtainable by the known two-phase interfacial process and the emulsion is worked up in known manner.
Inventors
- 👤 Klaus Berg
- 👤 Karsten-Josef Idel
- 👤 Ulrich Grigo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 00:48
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/02; C08J3/09; C08G; C08G64/00; C08G64/40; C08J2369/00
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
71 words
In the process for preparing a thermoplastic aromatic polycarbonate resin by the condensation of diphenols in the two phase interfacial process the improvement comprising adding to the aqueous emulsion of the polycarbonate thus produced 2.5 to 100 ppm of phosphorus acid said adding being before said emulsion is separated, said acid remaining in the aqueous phase of said process and said ppm being relative to the weight of diphenols thus condensed.
Claim 2
Dependent Claim
71 words
In the process for preparing a thermoplastic aromatic polycarbonate resin by the condensation of diphenols in the two phase interfacial process the improvement comprising adding to the aqueous emulsion of the polycarbonate thus produced 2.5 to 100 ppm of phosphorus acid said adding being before said emulsion is separated, said acid remaining in the aqueous phase of said process and said ppm being relative to the weight of diphenols thus condensed.
Claim 3
Dependent Claim
19 words
The improvement of claim 1 wherein said phosphorus acid is added in an amount of 5 to 10 ppm.
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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) | 1992-10-09 | 1993-04-10 | 1993-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-09 | 1997-04-10 | 1997-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-09 | 2001-04-10 | 2001-10-10 | $7700.00 | Window Closed / Lapsed |