POLYESTER RESIN AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide polytrimethylene naphthalate resin which can solve the easy breakableness of polytrimethylene naphthalate and can be used for molded articles or sheets formed by injection molding methods or extrusion molding methods. SOLUTION: This polyester resin is characterized in that a compound having three or more ester-forming functional groups in the molecule is copolymerized in a polyester containing trimethylene-2,6-naphthalate units as main repeating units. And the method for producing the polyester resin from a bifunctional carboxylic acid consisting mainly of 2,6-naphthalenedicarboxylic acid and/or its ester-forming derivative and/or the ester-forming derivative of the bifunctional carboxylic acid and a glycol consisting mainly of trimethylene glycol is characterized by performing the polycondensation reaction in the presence of a compound having three or more ester-forming functional groups in the molecule.