The present invention provides water-soluble or water-dispersible polyester resins prepared by depolymerizing a terephthalate plastic material in an alcoholysis/glycolysis reaction, and re-polymerizing the product by reacting with a polybasic acid and/or anhydride. The polyester resins of the invention contain 70% to 95% by weight of the terephthalate material, based on the total weight of the composition. The polyester resins of the present invention are useful as dispersants, for example in pigment preparations, and as binders in let-down varnishes, inks, coatings, etc, and as adhesion promoters in aqueous-based inks.