PET-BASED PES Russian patent published in 2023 - IPC C08G63/52 C08G63/54 C08L67/06 C08F222/06 C07C39/08 

FIELD: chemical industry.

SUBSTANCE: polyester resin based on polyethylene terephthalate and a method for producing polyester resin. The synthesis of polyester resin based on polyethylene terephthalate is carried out at the following ratio of components in parts by weight: polyethylene terephthalate - 23.00-28.00; propylene glycol - 23.00-28.00; zinc acetate - 0.50-2.50; maleic anhydride - 14.00-16.50; hydroquinone - 0.03-0.08; styrene - 30.00-35.00. As sources of ethylene glycol and terephthalic anhydride, glycolysis products of polyethylene terephthalate in propylene glycol are used. Zinc acetate is used as a glycolysis catalyst. Maleic anhydride is used as a reagent responsible for the reactivity of the finished resin. Hydroquinone is used as a stabilizer. Glycolysis is carried out in the presence of a zinc acetate catalyst for 6 hours at a temperature of 210±2°C, then the reaction mixture is cooled to 70-90°C, maleic anhydride is introduced into the reaction mixture and heated to 130°C is maintained for 1 hour, followed by an increase in temperature to 180°C and exposure for 1 hour, using a direct refrigerator, water and unreacted reagents are distilled off and the acid number of the mixture is adjusted to 35 mg/g and hydroquinone is introduced into the mixture, the temperature of the mixture is lowered to 90-100°C and the reaction mixture is mixed with styrene.

EFFECT: obtaining terephthalic polyester resins with increased chemical resistance by relatively inexpensive methods using waste recycled plastics based on polyethylene terephthalate.

3 cl, 2 tbl, 3 ex