Water-soluble or dispersible polyester resins made from terephthalate plastic materials useful as dispersant resins for inks

A method of preparing a water-soluble or water-dispersible polyester resin composition comprising subjecting a terephthalate polymer to a glycolysis/alcoholysis reaction, and re-polymerization reaction;

• wherein said glycolysis/alcoholysis reaction comprises reacting:
• (A) 73% to 95% by weight of at least one terephthalate polymer, based on the total weight of the composition;
• and
• (B) 0.5% to 30% by weight of at least one mono-, bi-, or higher-valent alcohol or oxyalkylated alcohol, based on the total weight of the composition;
• in order to get a reaction mixture;
• wherein the OH equivalents from the alcohol are less than the OH equivalents from the terephthalate polymer;
• and
• wherein said re-polymerization comprises adding to the reaction mixture:
• (C) 0.5% to 30% by weight of at least one polybasic carboxylic acid and/or anhydride, based on total weight of the composition;
• wherein the addition of the polybasic acid and/or anhydride is done either:
• i) sequentially, wherein all of the polybasic acid or anhydride is added to the reaction mixture after the glycolysis reaction has run for about 30 to 200 minutes, and/or the mixture exhibits a 15-minute clear peel, and/or the glycolysis reaction is run until there is essentially no reflux;
• or
• ii) essentially sequentially, wherein a portion of the polybasic acid and/or anhydride is added to the reaction mixture in the beginning at the same time as the terephthalate polymer and alcohol, with the remainder of the polybasic acid and/or anhydride being added:
• a) after the glycolysis reaction has run for about 30 to 200 minutes;
• and/or
• b) after the reaction mixture exhibits a 15-minute clear peel;
• and/or
• c) after the glycolysis reaction is run until there is essentially no reflux;
• wherein the ratio of the polybasic acid and/or anhydride added at the beginning of the reaction to the polybasic acid added after the glycolysis reaction has run for about 30 to 200 minutes, and/or the mixture exhibits a 15-minute clear peel, and/or the glycolysis reaction is run until there is essentially no reflux is 1:99 to 99:1;
• wherein the polyester resin has an acid value greater than 50 mg KOH/g;
• and
• wherein the polyester resin has a glass transition temperature (Tg) equal to or greater than 40° C.