METHOD OF PREPARING WHOLLY AROMATIC POLYESTER

摘要

Provided is a method of preparing a polyester resin suitable for electronic parts having its inherent mechanical strength and heat resistance, in which the amount of byproduct gas generated form molded articles is reduced. That is, provided is a method of preparing wholly aromatic polyester including: mixing monomers, introducing the mixed monomers into a reactor having a rectangular or trapezoidal plate type stirring impeller, and polymerizing the introduced monomers through esterification with a power per unit volume of 10 ~ 60 kW/m³, wherein a length (L) to diameter (D) ratio of the stirring impeller is 1 ~ 3 : 1, and a distance between the bottom of the reactor and a lower portion of the stirring impeller is 1/100 ~ 1/15 times of the diameter (D); b) pulverizing the obtained polymer; and c) solid state polymerizing the pulverized polymer. Provided is also a method of preparing wholly aromatic polyester having excellent heat resistant properties in which byproduct is effectively discharged by controlling a heating rate and reaction holding time between the weight loss initiating temperature and the melting point of a low molecular weight polymer generated in a melt polymerization in a solid state polymerization, adhesion does not occur, and discoloration due to heating does not occur. Provided is also a method of preparing a high heat resistant liquid crystal polyester resin composition having improved fluidity and used to form optical pick up parts, etc. by mixing a resin mixture including liquid crystal polyester resin A and liquid crystal polyester resin B, with a fiber and/or flake inorganic filler, wherein the difference of the melting points between liquid crystal polyester resin A and liquid crystal polyester resin B is in a certain range.