US Patent 7598339 Method for removing residual monomers from polyoxymethylenes

A process for removing residual monomers from polyoxymethylene homo- or copolymers, comprising the following process steps:a) the residual monomers are removed in gaseous form as vapors from the polymer in a devolatilization apparatus,b) the residual monomer vapors are removed through a vapor pipe,c) the residual monomers are condensed from the vapors in a condensation apparatus at from 1.09 to 102.4 bar and from 102 to 230° C., the temperature not falling below 102° C. at any point of the condensation apparatus, and those surfaces of the condensation apparatus which come into contact with the vapors being coated with a liquid film of condensed residual monomers.