| abstract |
1. Process for the discontinuous production of thermoplastic, high molecular weight copolyesters.n n n 2.1 While it is known in the production of poly-1,4-butylene terephthalate to reuse the distillate obtained during the polycondensation, this measure is unknown in the production of copolyesters. There is therefore a need to also use this resource-saving and economical measure in the production of copolyesters.n n n 2.2 The invention describes a process for the production of thermoplastic, high molecular weight copolyesters by transesterification, esterification and polycondensation of the starting components in the presence of a catalyst in the melt with the exclusion of oxygen, 5 to 30% by weight of the pure diol component being obtained by the polycondensation Diol (mixture) is replaced and the non-pretreated distillate containing the diol (mixture) is returned to the esterification. |