Process for the preparation of polyester polyols

摘要

The invention relates to a process for the preparation of polyesters with a terminal alcohol functional group, of medium molecular weight and a very low residual content of carboxylic acid functional group, through the polycondensation of dicarboxylic acids or anhydrides with diols and triols. The polycondensation reaction is catalysed by organometallic compounds of tin or titanium and is performed in a semi-continuous reactor with a fractionating column under reduced pressure of inert gas and under minimum reflux conditions compatible with the stoichiometry. The process according to this invention can be used to reduce production times for polyesters by more than 30% in comparison with the processes in the state of the art.