Patent ID: 6037437
Filing Date: 2000-03-14
Classification: C08G

Abstract:
In a method for producing an aromatic polycarbonate which comprises subjecting to a transesterification polymerization reaction at least one polymerizable material selected from the group consisting of:a molten monomer mixture of an aromatic dihydroxy compound and a diaryl carbonate, anda molten prepolymer obtained by reacting an aromatic dihydroxy compound with a diaryl carbonate,said transesterification polymerization reaction being performed in two or more polymerizers which are connected through a pipeline system toward an outlet for a final aromatic polycarbonate product, wherein said pipeline system comprises two or more pipes through which a molten aromatic polycarbonate having a number average molecular weight increased by said transesterification polymerization reaction is passed while contacting an inner wall of the pipes,wherein at least one of said polymerizers is used for producing an aromatic polycarbonate having a number average molecular weight of less than 2,500 and at least one remaining polymerizer is used for producing an aromatic polycarbonate having a number average molecular weight of 2,500 or more, andwherein at least one of said pipes is used for passing the aromatic polycarbonate having a number average molecular weight of less than 2,500 in a molten state and at least one remaining pipe is used for passing the aromatic polycarbonate having a number average molecular weight of 2,500 or more in a molten state,the method comprises passing a molten aromatic polycarbonate having a number average molecular weight of less than 2,500 through at least one of said pipes at a velocity of 0.05 m/sec. or more and passing a molten aromatic polycarbonate having a number average molecular weight of 2,500 or more through at least one remaining pipe at a velocity of 0.005 m/sec. or more.