Patent ID: 6605686
Filing Date: 2003-08-12
Classification: C08G

Abstract:
A method of keeping a mixture of an aromatic dihydroxy compound and a carbonic acid diester, comprising keeping a mixture consisting essentially of an aromatic dihydroxy compound and a carbonic acid diester in a molten state under the condition that the melt keeping parameter (A0) defined by the following equation (1):A0=âˆ’7.88+0.179Ã—log C0+3.354Ã—log T0+0.0078Ã—U0+0.0017&tgr;0â€ƒâ€ƒ(1) wherein C0 is the content (ppm) of oxygen in the atmosphere of a storage tank, T0 is the temperature (Â° C.) of the molten mixture in the storage tank, U0 is a temperature difference (Â° C.) between the heating medium of the storage tank and the molten mixture, and &tgr;0 is the average residence time (hr) of the molten mixture in the storage tank, is 0 or less.