METHOD FOR PRODUCING COPOLYMERIZED POLYESTER RESIN

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a copolymerized polyester resin having excellent color tone and resistant to discoloration in molten state by copolymerizing a phenylenedioxydiacetic acid as a dicarboxylic acid component to impart gas barrierness to the polymer. SOLUTION: The copolymerized polyester resin is produced by carrying out the esterification reaction or thransesterification reaction of a dicarboxylic acid component composed mainly of terephthalic acid and containing a phenylenedioxydiacetic acid as a copolymerizing component and a diol component composed mainly of ethylene glycol and subjecting the product to polycondensation reaction in the presence of a polycondensation catalyst and a phosphorus compound. A 20-120 C organic phosphite compound is used as the phosphorous compound.