Claims
- 1. In a process for the preparation of (co)polycarbonate by polycondensing a dihydroxy compound with a carbonic diester, the improvement which comprises (1) a first step conducted by feeding said dihydroxy compound, carbonic diester and a transesterification catalyst into a first reactor, the surface area which is made of a material containing iron in an amount of 20% by weight or less, wherein the temperature is maintained from 60.degree. to 300.degree. C. and the pressure is maintained at normal pressure to 0.1 Torr; and the molar ratio of carbonic diester to dihydroxy compound is 1.01 to 1.05 mol, to form a prepolymer; (2) a second step which comprises melt-polycondensing said prepolymer in a second reactor, the surface area which is made of a material containing iron in an amount greater than 20% by weight, in the presence of a catalyst selected from the group consisting of a boric acid salt or a nitrogen containing basic compound, wherein the second step is conducted at a temperature of from 200.degree. to 310.degree. C., a pressure of up to 10 Torr and such as to limit the phenols to 10,000 ppm or below.
- 2. The process for the preparation of a (co)polycarbonate by transesterification according to claim 1, wherein the prepolymer obtained in the first step contains a monohydric compound in an amount of 10 ppm or above, and the (co)polycarbonate obtained in the second step contains a monohydric compound in an amount of 10,000 ppm or below.
- 3. A (co)polycarbonate prepared by the process according to claim 1.
Priority Claims (1)
Number |
Date |
Country |
Kind |
5-89917 |
Apr 1993 |
JPX |
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Parent Case Info
This is a division of Ser. No. 08/229,292, filed Apr. 18, 1994, which is a continuation-in-part of Ser. No. 08/222,478, filed Apr. 1, 1994, now abandoned.
Foreign Referenced Citations (4)
Number |
Date |
Country |
55-142025 |
Jun 1980 |
JPX |
2153923 |
Jun 1990 |
JPX |
472327 |
Mar 1992 |
JPX |
488017 |
Mar 1992 |
JPX |
Divisions (1)
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Number |
Date |
Country |
Parent |
229292 |
Apr 1994 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
222478 |
Apr 1994 |
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