The foaming modified melamine-formaldehyde (MF) resin was prepared by using formaldehyde solution and paraformaldehyde with the mass ratio of 1 : 1, a certain amount of melamine and the modifiers (polyethylene glycol 200, caprolactam, diethylene glycol, glycol) under certain reaction conditions, then the MF foam plastic was prepared at 80℃. Taking the solid content, viscosity, storage life of the resin and the apparent density of the foam as indicators, the preparation parameters and formulations of the MF resin are optimized by orthogona...