Nylon-6

Abstract

Caprolactam and process water (up to 10 percent) are charged to an autoclave reactor. The vessel is purged with nitrogen, heated to 2100C and is pressurised to a maximum of 18 bar when polymerisation occurs. The pressure is maintained by bleeding steam. When the temperature rises to 270-280'C, the pressure is reduced to atmospheric after about 1 hour. Pressure is reduced to below atmospheric (at the same temperature' when the unreacted monomers and oligomers (cyclotriamide etc) are removed. The polymer product is finally removed by pressurising the vessel with nitrogen and extruding the polymer from the autoclave base. The polymer is quenched with water and cut into chips.