BigPatents India

The present invention relates to a process for continuous extraction of chips or flakes of polycaprolactam or of copolyamides of caprolactam and further polyamide forming starting materials in an essentially vertical extraction column using an aqueous extractant, which comprises using an extraction column that is divided into two zones and performing an extraction with a recirculating 15-40% strength by weight aqueous .epsilon.-caprolactam solution in the first zone and then with countercurrent water in the second zone, wherein the first zone of the extraction column has a larger diameter than the second zone and wherein the transition from the first zone to the second zone is equipped with a flow barrier.