Patent ID: 6753405
Filing Date: 2004-06-22
Classification: C08G

Abstract:
A process for the preparation of a copolycarbonate comprising transesterifying in the melt at least one diaryl carbonate with a mixture containing35 to 60 mol % of compounds of the formula (I): â€ƒwherein R1 to R4 independently of one another represent H, C1-C4-alkyl, phenyl, substituted phenyl or halogen, and 65 to 40 mol %, of compounds of the formula (II): â€ƒwherein R5 to R8 independently of one another are H, CH3, Cl or Br and X is C1-C5-alkylene, C2-C5-alkylidene, C5-C6-cycloalkylene or C5-C10-cycloalkylidene, said %, both occurrences being relative to the total molar amount of (I) and (II), characterized in that a final temperature of 270 to 330Â° C. is reached within less than 40 minutes after the starting temperature of 220 to 240Â° C.