The invention discloses a method for preparing copolyesters and polyesters in a degassing device. The copolyesters and polyesters are at least partially composed of 1,4-butanedicarboxylate units. The method is characterized in that crude polyester products are degassed under a pressure of 5 to 300 mbar with the addition of 0.1 wt% to 5 wt% entrainers based on the total mass of raw materials.
Area Code: DE
Application Number: CN201980069681.8
