TWO-STAGE HYDROLYSIS PROCESS FOR POLYMERIZATION OF NYLON 6

摘要

TWO-STAGE HYDROLYSIS PROCESS FOR POLYMERIZATION OF NYLON 6 A two-stage hydrolysis process for polymerizing epsilon-caprolactam is disclosed comprising a first stage from a temperature of about 180.degree.C. - 260.degree.C., a pressure of 20 to 150 psig, for a period of about 0.5 to 4 hours, then before equilibrium conditions are reached a second stage at a temperature of about 200.degree.C. - 260.degree.C., a pressure of about 100 - 900 Torr for a period of about 2 to 15 hours, while continuously removing most of the water so that water is removed both during hydrolyzation and during the subsequent polycondensation, whereby the cyclic dimer content of the shaped polymer article is below 0.2 percent by weight.