Continuous production of thermoplastic polyesters, includes a polycondensation step in which the partial pressure of the volatile reaction products is higher at the start of polycondensation than at the end

摘要

Continuous production of a thermoplastic polyester, comprises: (a) (trans)esterifying a dicarboxylic acid (ester) with a diol; and (b) polycondensing the resulting prepolymer. Step (b) is performed in such a way that the partial pressure of the volatile reaction products is higher at the start of polycondensation than at the end. An Independent claim is also included for apparatus for carrying out the process, comprising a cylindrical reaction vessel with a prepolymer inlet at one end and a polymer outlet at the other end; a mixing and transport device with an axis coaxial with the reaction vessel; and means for ensuring that the partial pressure of volatile reaction products is higher at the inlet end than at the outlet end.