Patent ID: 7598339

Claim:
A process for removing unconverted residual monomers from polyoxymethylene homo- or copolymers, comprising the following process steps: a) the residual monomers are removed in gaseous form as vapors at a temperature of from 70 to 300° C. and a pressure of from 0.005 to 50 bar from the polymer in a devolatilization apparatus, b) the residual monomer vapors are removed through a vapor pipe, the vapor temperature being kept above the boiling point, from 130 and 220° C., c) the gaseous residual monomers are condensed from the vapors in a condensation apparatus, wherein in step c), the condensation apparatus is operated at a pressure of from 2.0 to 5 bar and a temperature of from 120 to 135° C., and wherein those surfaces of the condensation apparatus which come into contact with the vapors are coated with a liquid film which comprises condensed residual monomers.