Patent US3639381A successfully refreshed from Google Patents.
US3943101A
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Process for preparing polycarbonates with a metal chelating agent
Assignee: General Electric Co
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Filing: 1974-05-31
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Granted: 1976-03-09
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Expires: 1994-05-31
Abstract
Abstract An improved process for preparing a color stable polycarbonate by carrying out the reaction in the presence of an additive. The additive employed herein is gluconic acid or its alkali metal salts.
Inventors
- 👤 Jorgen H. Vestergaard
- 👤 Gary W. Ragsdale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:11
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/20; C08G64/22; C08G64/24
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
48 words
In a process for preparing a color stable aromatic carbonate polymer by reacting a dihydric phenol and an alkali metal hydroxide with a carbonate precursor, the improvement which comprises carrying out the reaction in the presence of a stabilizing amount of gluconic acid or its alkali metal salts.
Claim 2
Dependent Claim
48 words
In a process for preparing a color stable aromatic carbonate polymer by reacting a dihydric phenol and an alkali metal hydroxide with a carbonate precursor, the improvement which comprises carrying out the reaction in the presence of a stabilizing amount of gluconic acid or its alkali metal salts.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein the dihydric phenol is 2,2-bis(4-hydroxyphenyl) propane.
Claim 4
Dependent Claim
11 words
The process of claim 1 wherein the carbonate precursor is phosgene.
Claim 5
Dependent Claim
20 words
The process of claim 1 wherein a polyfunctional organic compound is reacted with the dihydric phenol and the carbonate precursor.
Claim 6
Dependent Claim
13 words
The process of claim 4 wherein the polyfunctional organic compound is diphenolic acid.
Claim 7
Dependent Claim
15 words
The process of claim 1 wherein the dihydric phenol is a halogen substituted dihydric phenol.
Claim 8
Dependent Claim
13 words
The process of claim 6 wherein the halogen substituted dihydric phenol is tetrabromobisphenol-A.
Claim 9
Dependent Claim
21 words
The process of claim 1 wherein the dihydric phenol is a combination of dihydric phenol and a halogen substituted dihydric phenol.
Claim 10
Dependent Claim
13 words
The process of claim 1 wherein the alkali metal hydroxide is sodium hydroxide.
Claim 11
Dependent Claim
16 words
The process of claim 1 wherein the alkali metal salt of gluconic acid is sodium gluconate.
Claim 12
Dependent Claim
33 words
The process of claim 1 wherein the stabilizing amount of gluconic acid or its alkali metal salts is from about 0.1 to about 2.0 weight percent based on the weight of dihydric phenol.
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) | 1979-03-09 | 1979-09-08 | 1980-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-09 | 1983-09-08 | 1984-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-09 | 1987-09-08 | 1988-03-09 | $7700.00 | Window Closed / Lapsed |