This invention discloses a production process for high-viscosity nylon 6 through devolatilization and viscosity enhancement. Raw materials including caprolactam, ring-opening agent, and molecular weight regulator are thoroughly mixed. The mixture undergoes preheating, pre-polymerization, and post-polymerization to produce low-viscosity Grade I nylon 6 melt. This melt then enters a high-efficiency devolatilization self-cleaning reactor for viscosity enhancement and devolatilization treatment. followed by continuous devolatilization in a devolatilization twin-screw extruder to obtain a high-viscosity Grade II nylon 6 melt with a relative viscosity exceeding 3.8. The melt is then pelletized, dried, and cooled to yield the final product. This process effectively resolves the discharge and conveying difficulties associated with producing high-viscosity nylon 6 in post-polymerization towers. The resulting Class II nylon 6 melt contains extractable matter below 0.5 wt%, eliminating the need for extraction. Direct pelletization and drying are achievable, significantly reducing material and energy consumption caused by hot water extraction and solid-phase viscosity enhancement. This lowers production costs and achieves higher added value.
Country Code: CN
Application Number: CN202310157132.4
