Amorphous copolyesters containing monomers derived from bisphenols

Amorphous copolyesters based on combinations of ethylene glycol (EG) and 1,4-cyclohexane-dimethanol (CHDM) as diols with terephthalic acid have excellent properties, such as toughness, clarity, and chemical resistance and are well known commercial polymers. Several different hydoxyethoxylated bisphenols were copolymerized into the backbone of these amorphous copolyesters in order to raise the glass transition temperature (T-g). The incorporation of bis[4-(2-hydroxyethoxy)phenyl]sulfone (SEO-2) into the amorphous copolyester backbone led to significant Tg increase and improvement in resistance to lipids. Melt viscosity and other mechanical and physical properties were unchanged by the addition of SEO-2.