Method for preparing polyester copolymer containing amide link

Abstract

A method for preparing polyester copolymer containing amide link, which can reduce the phase separation of a polyester component and an amide component by improving the compatibility therebetween is disclosed. The method for preparing polyester copolymer comprises the step of polymerizing macrocyclic polyester oligomer and cyclic amide monomer. Wherein, it is preferable that the macrocyclic polyester oligomer is obtained by reacting bis(hydroxyalkyl)ester with dicarboxylic acid chloride in the presence of unhindered amine, and the bis(hydroxyalkyl)ester is obtained by. depolymerizing polyester. resin. Also, lit is preferable that the cyclic amide monomer is E-caprolactam having a cyclic structure and having 2 or more carbon atoms, and the amount of the macrocyclic polyester oligomer is 5 to 99% by weight with respect to total amount of the macrocyclic polyester oligomer and the cyclic amide monomer.

Dependencies are inferred from the claim text.