LOW SPECIFIC-GRAVITY POLYESTER RESIN

摘要

PROBLEM TO BE SOLVED: To provide a low specific-gravity polyester resin, easy in separating from PET in the recycling process. SOLUTION: This polyester polymer has terephthalic acid as a main carboxylic acid component and a compound expressed by chemical formula (1) and/or (2), as a diol component, wherein a grass transition temperature of this polyester is above 40 deg.C, and the density thereof is below 1.10 g/cm3.