KR960041228A - Method of producing polycarbonate - Google Patents

Abstract

The present invention relates to a method for producing polycarbonate, which comprises reacting an alkali metal salt of diphenol in an aqueous phase with a phosgene in an organic phase according to a two-phase interfacial condensation method to obtain an oligomer, wherein (1) the reaction product is dissolved but water is dissolved. Contacting an organic phase containing an inert organic solvent which does not have an inert organic solvent with an aqueous phase containing water, diphenols and alkali metal hydroxides under emulsification conditions to generate an emulsion, and (2) limiting the emulsion under phosgene and condensation reaction conditions. It provides a process for producing a polycarbonate, characterized in that it comprises a step of obtaining an oligomer by contacting under mixing conditions weaker than the emulsification conditions.

By the above process, a polycarbonate excellent in color and small in color change after melt molding can be obtained.

Description

Method of producing polycarbonate

Since this is an open matter, no full text was included.

1 is a plan view of a reaction field used to practice the present invention. 2 is a plan view of a reaction apparatus of another embodiment used to practice the present invention.

Claims (9)

A method for producing a polycarbonate comprising reacting an alkali metal salt of diphenol in an aqueous phase with a phosgene in an organic phase according to a two-phase interfacial condensation method to obtain an oligomer, wherein (1) an inert that dissolves the reaction product but does not dissolve water. Contacting an organic phase containing an organic solvent with an aqueous phase containing water, diphenols and alkali metal hydroxides under emulsification conditions to form an emulsion, and (2) making the emulsion weaker than the emulsification conditions under condensation with phosgene. Method of producing a polycarbonate, characterized in that it comprises a step of obtaining an oligomer by contacting under mixed conditions. The method for producing a polycarbonate according to claim 1, wherein the number of wavers We is 1 × 10 ⁴ or more as the emulsification condition of the step (1), and (2) the number of wavers We is less than 1 × 10 ⁴ as the conditions of the step. The method for producing a polycarbonate according to claim 1, wherein P / qRK of the following general formula is at least 200 as the fixed emulsification condition of (1) and P / q of the following general formula is less than 200 as the mixing condition of the process of (2). _{P / q = N p · ρ} · n 3 · d 5 / (g · q) (㎏ · m / ℓ) Where N _p is a constant, 0.8 in the tank mixer, 2.31 in the tubular mixer, ρ is the specific gravity (kg / m 3), n is the rotational speed (rps) of the stirrer, and d is the blade diameter (m) of the stirrer. Where g is gravitational acceleration (m / sec ² ) and q is flow rate (l / sec). The process according to any one of claims 1 to 3, characterized in that the production of an emulsion is carried out in the presence of at least one chain stopper and / or at least one polycondensation catalyst. The process according to claim 1, wherein the production of the emulsion is carried out in a dynamic mixer (mechanical emulsifier) and / or in a static mixer. The method according to any one of claims 1 to 5, wherein the contact with phosgene is carried out at a pressure of 0 to 10 kg / cm 3 G and a temperature of 80 ° C or lower. The process according to claim 1, wherein the contact with the phosgene is carried out in a piston flow reactor. A method for producing a polycarbonate comprising reacting an alkali metal salt of diphenol in an aqueous phase with a phosgene in an organic phase according to a two-phase interfacial condensation method to obtain an oligomer, wherein (1) an inert that dissolves the reaction product but does not dissolve water. An organic phase containing an organic solvent and an aqueous phase containing water, diphenols and alkali metal hydroxides are contacted under emulsification conditions to form an emulsion, and (2) mixing the emulsion with phosgene weaker than the emulsification conditions under condensation reaction conditions. Contacting under conditions to obtain an oligomer, wherein the emulsified state is maintained until the alkali metal salt of diphenol in the aqueous phase is lost. A method for producing a polycarbonate comprising reacting an alkali metal salt of diphenol in an aqueous phase with a phosgene in an organic phase according to a two-phase interfacial condensation method to obtain an oligomer, wherein (1) an inert that dissolves the reaction product but does not dissolve water. Contacting an organic phase containing an organic solvent with an aqueous phase containing water, diphenols and alkali metal hydroxides under emulsification conditions to produce an emulsion, (2) making the emulsion weaker than emulsification conditions under the condensation reaction conditions with phosgene. Contacting under mixed conditions to obtain an oligomer at which time the emulsion is emulsified in the emulsion until the alkali metal salt of diphenol in the aqueous phase is lost; and (3) the organic phase in which such oligomer is dissolved is separated from the aqueous phase and, if necessary, Water and alkali metal hydroxides simultaneously with additional amounts of inert organic solvents Method for producing a polycarbonate, comprising the step of obtaining a polycarbonate by contacting with an aqueous phase containing a polycondensation reaction conditions. ※ Note: The disclosure is based on the initial application.