Preparation of nylon 66 polymers from 1,8-diazacyclotetradecane-2,7-dione

A process for the production of nylon 66 polymer or copolymer from 1,8-diazacyclotetradecane-2,7-dione which comprises (a) forming a reaction mixture containing 10 to 90 parts by weight 1,8-diazacyclotetradecane-2,7-dione and a complementary amount of at least one member of the group consisting of the salt of adipic acid and hexamethylenediamine, and epsilon-caprolactam, (b) heating said mixture under a pressure greater than atmospheric pressure, (c) slowly lowering the pressure to atmospheric pressure while increasing the temperature to about 275 degrees C., (d) maintaining the temperature at about 275 degrees C. and at a pressure no more than atmospheric pressure until polymer having a relative viscosity of at least about 25 is obtained, where relative viscosity is measured at 25 degrees C. in a solution of 8.4% by weight polymer in formic acid containing 10% by weight water.