PURPOSE:To obtain a high-molecular weight polycarbonate having narrow molecular weight distribution and excellent thermal stability by subjecting a bishydroxy compound and a bisaryl carbonate to melt polycondensation in the presence of a catalyst of phosphorus compound. CONSTITUTION:A bishydroxy compound [e.g. bis-(4-hydroxyphenyl)methane, etc.] is blended with a bisaryl carbonate (e.g. diphenyl carbonate) in a ratio of 1:1-1.1 (molecular ratio) and subjected to melt polycondensation in the presence of preferably 100-5,000ppm (based on bishydroxy compound) of a catalyst of phosphorus compound (e.g. triphenyl phosphate) of the formula (R1 to R3 are 1-25C alkyl, 6-25C aryl, 1-25C alkyloxy or 6-25C aryloxy) to give the objective polycarbonate.

PROBLEM TO BE SOLVED: To decrease the initial coloration of a polycarbonate by concentrating an org. solvent soln. of a polycarbonate prepolymer to precipitate primary particles, subiecting a slurry soln. of the primary particles to wet extrusion granulation or compression molding granulation, and subiecting the resultant granules to solid phase polymn. SOLUTION: A melt mixture of an arom. dihydroxyl compd. (e.g. bisphenol A) and a carbonic diester (e.g. diphenyl carbonate) is subjected to thermal reaction in the presence of a polymn. catalyst to give a polycarbonate prepolymer having a viscosity average mol.wt. of 3,000-50,000. The prepolymer is thermally dissolved in a solvent wherein the solubility of the prepolymer is 0.1-5wt.%, and the soln. is allowed to cool to give a slurry soln. with a concn. of 1-70wt.%. A precipitate is separated from the slurry soln. and dried to give a powder with an average size of 5-100μm, which is granulated with a wet extrusion granulater. The resultant granules having an average size of 0. 3-5 mm and a specific surface area of 1-100m /g are charged into a reactor and subjected to solid phase polymn. at 180-280 deg.C under an N2 -gas flow to give a polycarbonate hardly exhibiting initial coloration.

Method for producing polycarbonate

Citations

Production of polycarbonate

Related Papers (5)

Bisphenol copolymerization polycarbonate and electrophotographic sensitized material using the same

Polycyanoaryl ether and production thereof

Aromatic polycarbonate terpolymer

Alicyclic polycarbonate and its production

Phenolic compound, epoxy compound and resin composition containing the same