US4864011A
Expired / Lapsed
US
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Method of preparing an aromatic polycarbonate with phenolic chloroformate chain stopper
Assignee: General Electric Co
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Filing: 1987-09-18
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Granted: 1989-09-05
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Expires: 2007-09-18
Abstract
Abstract The invention relates to a method of preparing aromatic polycarbonate according to the two-phase interface process. The molecular weight is controlled by the addition of a chain stopper. The use of a phenolic chloroformate as a chain stopper leads to a polycarbonate having a low content of volatile constituents.
Inventors
- 👤 Jan Bussink
- 👤 Hugo G. E. Ingelbrecht
- 👤 Vinayak Vaishnav
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:16
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/20; C08G64/22; C08G64/24; C08G64/04; C08G64/06; C08G64/14
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
112 words
A method of preparing an aromatic polycarbonate comprising reacting a carbonate precursor with a diphenol in the presence of a chainstopper according to the phase boundary process wherein the chainstopper is a compound of the formula ##STR2## wherein R is an alkyl radical or an aryl radical having 1-12 carbon atoms or a hydrogen atom and n is a whole number from 0-5 inclusive with the proviso that when n is other than zero and R is an alkyl radical, then the chain stopper is added to the reaction mixture after 20 to 80 percent of the quantity of carbonate precursor to be added totally has been added to the reaction mixture.
Claim 2
Independent Claim
112 words
A method of preparing an aromatic polycarbonate comprising reacting a carbonate precursor with a diphenol in the presence of a chainstopper according to the phase boundary process wherein the chainstopper is a compound of the formula ##STR2## wherein R is an alkyl radical or an aryl radical having 1-12 carbon atoms or a hydrogen atom and n is a whole number from 0-5 inclusive with the proviso that when n is other than zero and R is an alkyl radical, then the chain stopper is added to the reaction mixture after 20 to 80 percent of the quantity of carbonate precursor to be added totally has been added to the reaction mixture.
Claim 3
Dependent Claim
38 words
A method as claimed in claim 1, characterised in that the chain stopper is added to the reaction mixture after 20-80% of the quantity of carbonate precursor to be added totally have been added to the reaction mixture.
Claim 4
Dependent Claim
21 words
A method as claimed in claim 1, wherein the quantity of chainstopper is 2-7 mole % based on moles of diphenol.
References Cited (Backward Citations)
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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) | 1992-09-04 | 1993-03-06 | 1993-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-04 | 1997-03-06 | 1997-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-04 | 2001-03-06 | 2001-09-05 | $7700.00 | Window Closed / Lapsed |