Polyamide prepolymer, polyamide, and process for producing these

摘要

A mixture substantially comprising caprolactam and water is heated for at most 30 minutes to obtain a polyamide prepolymer having an amino end group content of at least 0.1 mmol/g and a cyclic oligomer content of at most 0.6% by weight. An aqueous solution of caprolactam having a water content of from 2 to 20% by weight is heated under pressure at a temperature of from 200 to 330° C. for 1 to 30 minutes to obtain a polyamide prepolymer having an amino group content of at least 0.1 mmol/g and a cyclic oligomer content of at most 0.6% by weight.