Method for continuous production of polyesters or copolyesters

A process of producing polyesters and copolyesters by continuous esterification of dicarboxylic esters and diols or by continuous transesterification of dicarboxylic esters with diols in n reaction pressure stages (2, 4, 32, 34, 36) connected in series., wherein the pressure existing in the first reaction pressure stage (2, 32), which is higher as compared to the remaining reaction pressure stages (4, 34, 36), successively decreases from reaction pressure stage to reaction pressure stage, the combined vapor flows of the individual reaction pressure stages ate introduced into a rectifying column (12, 47) and rectified, and the diol component obtained at the bottom of the rectifying column is recirculated at least to the first reaction pressure stage, characterized in that at least the last reaction pressure stage has a vacuum, the pressure in the rectifying column (12, 47) is larger than in the last reaction pressure stage, and the vapors discharged from the last reaction pressure stage are condensed to the pressure existing in the rectifying column.