Method of continuously producing polyamide 6 using recycled lactam

Abstract

The invention concerns a method of continuously producing polyamide 6 using recycled lactam from extraction and melt-demonomerizing stages. According to the invention, the cyclic oligomers present in the recycled lactam owing to the addition of .epsilon.-caprolactam (fresh lactam) are dissolved in the lactam as a function of the concentration of the oligomers in the product in use, at a dissolution temperature of between 120.degree. C. and 180.degree. C. The solution is then passed to a treatment, the solution preferably being introduced into a closed system and hydrolyzed in the fusible phase under pressure, at water contents of between 3 and 15% and temperatures ranging from 220 to 280.degree. C. With a constant low water content being set, the melt is then fed to the polymerization process in a further pressure stage incorporating a gas chamber (polymerizator).

Dependencies are inferred from the claim text.