Method of and apparatus for manufacturing formed bodies from synthetic,linear,high molecular weight polyamides of low monomer content

摘要

Polycaprolactam is purified to a monomer content of not more than 3% by extraction under pressure with a non-solvent for the polymer at a temperature above the normal boiling point of the non-solvent and the melting point of the polymer, the non-solvent being removed by de-gassing. Specified non-solvents are water or mixtures of water and alcohol or ketones, or ketones. The purification may be a step in a continuous polymerization process and is stated to be operable for polyamides generally. In the example polycaprolactam is purified to an extractables content of 0.5%.