POLYESTER AND METHOD FOR PREPARING SUCH A POLYESTER

摘要

A polyester, including ethylene 2,5-furandicarboxylate units, has an intrinsic viscosity of at least 0.45 d L/g, and has a relative content of carboxylic acid end groups, expressed as the fraction of the molar amount of carboxylic acid end groups divided by the sum of the molar amounts of hydroxyl end groups and carboxylic acid end groups in the range of 0.10 to 0.70. The polyester can be prepared with a method wherein a starting mixture comprising 2,5-furandicarboxylic acid and ethylene glycol is subjected to esterification and subsequent polycondensation at reduced pressure when the molar ratio of 2,5-furandicarboxylic acid to ethylene glycol in the starting mixture is 1:1.01 to 1:1.15, where water, that is formed during the reaction between 2,5-furandicarboxylic acid and ethylene glycol, and some ethylene glycol are removed in a distillation system, and where ethylene glycol that is removed with water, is separated from water and at least partly recycled.

主权项

1. A polyester comprising ethylene 2,5-furandicarboxylate units, which polyester has an intrinsic viscosity of at least 0.45 dL/g, and which polyester has a relative content of carboxylic acid end groups, expressed as the fraction of the molar amount of carboxylic acid end groups divided by the sum of the molar amounts of hydroxyl end groups and carboxylic acid end groups, in the range of 0.10 to 0.70.