Patent ID: 9683078
Date: 2017-06-20
CPC Classifications: C08G

Claim:
1. A method for preparing a branched polycarbonate via a continuous two-phase phosgenation interfacial process, comprising the steps of: a) dissolving a branching agent into an aqueous solution of alkali metal hydroxide to form a first aqueous phase, then conducting a pre-reaction between the first aqueous phase and phosgene in the existence of an inert organic solvent to prepare a prepolymer; wherein the mole ratio of the phosgene to the phenolic hydroxyl group of the branching agent is from 0.1:1 to 2:1; b) dissolving a bisphenol into an aqueous solution of alkali metal hydroxide to form a second aqueous phase, then conducting a reaction among the prepolymer prepared by step a), the second aqueous phase and phosgene in the existence of an inert organic solvent to prepare a branched polycarbonate oligomer; and c) adding an end capping agent and a catalyst into the oligomer prepared by step b) to carry out the chain extension and end capping reaction to obtain a solution of a high molecular weight branched polycarbonate, and finally obtaining the branched polycarbonate by separating and purifying.