Method for continuously preparing makrolon by phosgene interface polycondensation

Abstract

The invention relates to the technical field of the preparation of makrolon, in particular to the technical field of the continuous preparation of the makrolon by interface polycondensation. The continuous synthesis of the makrolon resin can be completed by a photochemical reactor, an oligomerization kettle and two polycondensation kettles. The method comprises the following steps of: leading bisphenol sodium salt solution, phosgene and organic solvent to pass through the photochemical reactor to generate makrolon prepolymer; charging the makrolon prepolymer into the oligomerization kettle to stop the photochemical reaction by controlling the temperature, and to obtain the makrolon prepolymer with homogeneous quality; mixing the homogeneous prepolymer, the blocking agent, the secondary sodium hydroxide and the catalyst to enter into the first polycondensation kettle to start the polycondensation, wherein the polycondensation is an exothermic reaction, cooling by a polycondensation kettle jacket, and controlling the polycondensation temperature to be lower than the boiling point of the organic solvent; and curing the material by the second polycondensation kettle to obtain a makrolon product. The method is simple in makrolon synthesis equipment, stable in product quality and small in molecular weight fluctuation.

Description

technical field [0001] The invention relates to the technical field of polycarbonate preparation, in particular to the technical field of continuous polycarbonate preparation by phosgene interfacial polycondensation method. Background technique [0002] Polycarbonate (PC), is an amorphous, tasteless, odorless, non-toxic, transparent thermoplastic polymer with excellent mechanical, optical and electrical properties such as transparency, high hardness, heat resistance, wear resistance, and UV resistance. It is widely used in many fields such as machinery, medical equipment, electronic appliances, communication equipment, aviation, auto parts, etc. It is one of the six major engineering plastics in modern industry. [0003] The polycarbonate manufacturers in the world are mainly companies from the United States, Germany and Japan. Among them, General Electric Company of the United States, Bayer Company of Germany, Dow Chemical Company of the United States, Teijin Chemical Compa...

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Problems solved by technology

[0011] Chinese patent application number 201010126768.5 discloses a method for preparing polycarbonate by a continuous two-phase interface method. In this method, an alkali metal solution containing polyphenols is mixed with 5-20% of the total amount of phosgene and an organic solvent to obtain an initial emulsion. , and then mix the above emulsion with the remaining phosgene and a certain amount of organic solvent to prepare polycarbonate prepolymer emulsion, and finally obtain polycarbonate resin through capping and coupling reaction, which can improve the conversion of monomer rate, but the stability of the obtained emulsion is poor, and the composition is easy to fluctuate, which eventually leads to fluctuations in the quality of polycarbonate products

The method firstly mixes bisphenol compound and alkali metal hydroxide aqueous solution to form a water phase, and mixes phosgene with an inert organic solvent to form an organic phase; reaction; after the photochemical reaction is completed, the end-capping reaction and coupling reaction are carried out in sequence, and polycarbonate is finally separated. This method improves the reaction efficiency of phosgene and sodium phenolate, shortens the phosgenation reaction and the entire polycondensation reaction time , but this method will cause the temperature of the material to rise sharply and the pressure of the system to increase during the phosgenation reaction, which will accelerate the hydrolysis rate of the chloroformate group, thereby increasing the consumption of phosgene

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