Continuous process for the hydrolytic production of polycaprolactam by tempering unextracted granular polymer material with moist inert gas

Claim 1

In a process for the hydrolytic polymerization of caprolactam into polycaprolactam in the presence of a chain regulator, the improvement comprising: (a) employing, during said polymerization, a chain regulator selected from the group consisting of (i) alkylammonium carboxylates and (ii) hexamethylenediamine/monocarboxylic acid mixtures wherein the mole ratio of hexamethylenediamine to monocarboxylic acid is from about 0.5:1 to about 1.1:1, to form crude polycaprolactam; (b) preparing granules from the crude, unextracted polycaprolactam thus produced; and (c) tempering said granules at a temperature of from about 130° C. to about 200° C. for a period of from 8 to about 100 hours in a stream of inert gas containing from 2 to about 15 weight percent water; whereby the granules thus tempered exhibit a higher polymer relative viscosity and lower extractables content than the crude unextracted granules while maintaining stable relative viscosity, amino end groups, and dyeability under extrusion conditions.