Patent US4115358A successfully refreshed from Google Patents.
US4115358A
Expired / Lapsed
US
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Process for preparing aromatic carbonate polymers
Assignee: General Electric Co
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Filing: 1976-09-03
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Granted: 1978-09-19
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Expires: 1996-09-03
Abstract
Abstract A process for preparing a polycarbonate, which polycarbonate has improved resistance to thermal degradation and improved impact resistance and consists of reacting at least 70 weight percent of a stoichiometric amount of a carbonate precursor such as phosgene with a dihydric phenol such as bisphenol-A while simultaneously adding to the reaction medium an alkali metal hydroxide such as sodium hydroxide to maintain a pH of 6.0 to about 10.0. The pH is then raised to 11.0 by adding sufficient alkali metal hydroxide.
Inventors
- 👤 Jorgen H. Vestergaard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:17
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/20; C08G64/22; C08G64/24
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
116 words
A process of preparing a carbonate polymer having improved resistance to thermal degradation and improved impact resistance, which process consists of (a) mixing 2,2 bis(4-hydroxyphenyl) propane in an aqueous medium with a solvent for the carbonate polymer, a molecular weight regulator and a catalyst, (b) adding 70-95 weight percent of the stoichiometric quantity of a carbonate precursor with the 2,2 bis(4-hydroxyphenyl) propane while adding, simultaneously with the carbonate precursor, sufficient alkali metal hydroxide to maintain a pH of 6.0 to about 10.0 and (c) adding sufficient alkali metal hydroxide solution to raise the pH to at least 11.0 and (d) maintaining said pH while reacting the remaining amount of the stoichiometric quantity of the carbonate precursor.
Claim 2
Dependent Claim
116 words
A process of preparing a carbonate polymer having improved resistance to thermal degradation and improved impact resistance, which process consists of (a) mixing 2,2 bis(4-hydroxyphenyl) propane in an aqueous medium with a solvent for the carbonate polymer, a molecular weight regulator and a catalyst, (b) adding 70-95 weight percent of the stoichiometric quantity of a carbonate precursor with the 2,2 bis(4-hydroxyphenyl) propane while adding, simultaneously with the carbonate precursor, sufficient alkali metal hydroxide to maintain a pH of 6.0 to about 10.0 and (c) adding sufficient alkali metal hydroxide solution to raise the pH to at least 11.0 and (d) maintaining said pH while reacting the remaining amount of the stoichiometric quantity of the carbonate precursor.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein the carbonate precursor is carbonyl chloride.
Claim 4
Dependent Claim
14 words
The process of claim 1 wherein the alkali metal hydroxide solution is sodium hydroxide.
Claim 5
Dependent Claim
10 words
The process of claim 1 wherein the catalyst is triethylamine.
Claim 6
Dependent Claim
42 words
The process of claim 1 wherein 100 percent of the stoichiometric quantity of the carbonate precursor is added while maintaining the pH at 6.0 to about 10.0 and then adding sufficient alkali metal hydroxide to raise the pH to at least 11.0.
References Cited (Backward Citations)
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Cited
US3386954A
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US3248366A
Cited
US3410823A
Cited
US3466260A
Cited
US3468846A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-18 | 1982-03-20 | 1982-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-18 | 1986-03-20 | 1986-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-18 | 1990-03-20 | 1990-09-19 | $7700.00 | Window Closed / Lapsed |