Patent ID: 10000607

Abstract:
A polyamide resin is produced through polycondensation by melt-kneading a polyamide oligomer having a relative viscosity of from 1.1 to 1.3 and a water content of 3% by mass or less in a cylinder (S) of an extruder. The extruder includes open vents (OV1) and (OV2) and vacuum vents (V1) and (V2). The open vent (OV1) is arranged near a supply port (A3), e.g., above the supply port (A3), and a pressure-decreasing element (Y) is arranged on an upstream side with respect to positions of the vacuum vents (V1) and (V2). In addition, the open vent (OV2) is arranged in a preceding area (OA) and is brought into a pressurized state.