Method for preparing polycarbonate

Abstract

The invention relates to a method for preparing polycarbonate. The method utilizes an interface method, and comprises the steps of: mixing alkaline aqueous solution of one or more dihydroxy aromatic hydrocarbons and organic solution of carbonyl chloride(phosgene); controlling the pH value to be between 9 and 12.5 in the whole process; and performing an interfacial polymerization reaction of a phenol chain terminator, the dihydroxy aromatic hydrocarbons and the phosgene in the presence of a catalyst, namely an amphiphilic block copolymer to prepare the polycarbonate. The method utilizes the amphiphilic block copolymer as the catalyst for preparing the polycarbonate by the interface method, which can increase the utilization rate of the carbonyl chloride, reduce the consumption of the carbonyl chloride, and improve the utilization rate of bisphenol; the catalyst can promote the rapid transformation of chloroformate and obtain a polycarbonate product with low inclusion amount of dihydroxy aromatic compounds; and no phenol precipitations are precipitated after a wastewater phase is acidified, and a catalyst material can be treated and recovered by adopting a conventional method.

Description

technical field [0001] The invention relates to the field of polymer material preparation, in particular to a method for preparing polycarbonate, wherein an amphiphilic block copolymer is used as a phase transfer catalyst and a condensation catalyst. Background technique [0002] Polycarbonate (Polycarbonate, PC) is a high-performance polymer material, widely used as an engineering plastic in the fields of automobiles, electrical appliances, construction and household appliances. [0003] The industrial production of polycarbonate is mainly carried out by the interface method, that is, the alkaline aqueous solution of one or several dihydroxy aromatic hydrocarbons is mixed with the organic solution of carbonyl chloride (phosgene) and then subjected to photochemical reaction to form a prepolymer. , adding a molecular weight terminator or branching agent, catalyst, etc., for interfacial polymerization to generate polycarbonate. Although practice has proved that organic tertia...

AI Technical Summary

Problems solved by technology

In recent years, for example, described in U.S. Patent No. 5,391,692, it has been found that phase transfer catalysts quaternary ammonium halides and quaternary phosphorus halides can replace tertiary amines as catalysts for polycarbonate interfacial preparation methods, thereby increasing the phosgene Utilization, however, the use of these catalysts also inhibits the conversion of chloroformate-terminated intermediate polymers into useful species, such as end- or hydroxyl-terminated polycarbonates, while generating concomitant chloroformate-terminated end product

Since the presence of chloroformate-terminated species is generally undesirable in polycarbonate products, the use of quaternary ammonium halides and quaternary phosphorus halides as catalysts, although able to improve phosgene utilization, has not been widely adopted on an industrial scale. use

[0005] U.S. Patent No. 5,519,105 and U.S. No. 5,510,449 disclose that the combined use of phase transfer catalysts and tertiary amines can increase the effective utilization rate of carbonyl chloride, and simultaneously improve the conversion rate of chloroformate-terminated polymers into useful products, However, the combined use of the two catalysts has its disadvantages, such as the production system including the need to use two independent processes for recovering the catalyst

Images