Process for continuous extraction of polyamide particles in an essentially vertical extraction column using an aqueous extraction agent

摘要

"PROCESS FOR CONTINUOUS EXTRACTION OF POLYAMIDE PARTICLES IN AN ESSENTIALLY VERTICAL EXTRACTION COLUMN USING A WATER EXTRACTION AGENT". a process for continuous extraction of polyamide particles is revealed, from a circulating solution in a vertical extraction column, subdivided into two zones. The polyamide is treated in the first zone with an aqueous solution of sym -caprolactam with 15-40% by weight of sym -caprolactam as an extraction agent of 100 to 140 198 C, and water is used in a second zone as an extraction agent at a temperature of 5-40 198 C lower. The process provides polyamides with a low monomer and oligomer content, enough to be economically extracted.