METHOD FOR MANUFACTURING POLY(HEXAMETHYLENE ADIPAMIDE) FROM MONOMETHYLADIPATE AND HEXAMETHYLENEDIAMINE

摘要

An improved method for manufacturing poly(hexamethylene adipamide), i.e. nylon 6,6, by reacting monomethyl adipate with hexamethylenediamine in an approximately equimolar ratio in the presence of water at a temperature of 100 to 165 ~C while simultaneous distilling off of a stoichiometric amount of methanol. The resulting aqueous intermediate product is then heated to 200 to 260 ~C while distilling off substantially all water at a pressure of 150 to 250 psig (1.03 x 106 to 1.72 x 106 Pa) followed by reducing the pressure to atmospheric pressure and increasing the temperature to 270 to 280 ~C to polycondense the distillate residue. Such a process is useful in producing high purity commercial grade poly(hexamethylene adipamide) that advantageously avoids problems caused by N-methylation of the polyamide.