Thermoplastic aromatic polycarbonate prodn. - by interfacial method in two consecutive reactors with partial recirculation of aq. phase for direction formation and maintenance of oil-in-water emulsion

摘要

Prodn. of thermoplastic aromatic polycarbonates (I) by interfacial condensation of COCl2, diphenols (II), chains stoppers and opt. branching agents involves phosgenation of an aq. alkali salt soln. (III) contg. (II) in the presence of water-immiscible solvent(s) (IV) for (I) and the oligomers at pH 8-14, using polycondensation catalysts (V) and Z consecutive reactors. When reaction is complete, the aq. reaction phase (VI) is partly recycled to the phosgenation reactor with the raw materials, in such an amt. that an oil-in-water emulsion forms directly and is maintained throughout the entire reaction time in both reactors. USE/ADVANTAGE - (I) are useful for making films, fibres, panels and other mouldings used in the electrical and building sectors, e.g. lamp housings, optical lenses and compact discs, esp. optical and audio discs. (I) with constant and reproducible mol.wt. can be produced very economically.