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 orthogonal experiments design with the reaction temperature,pH value, mole ratios of formaldehyde to melamine (F/M),the types of the modifiers and their contents as affecting factors. Based on the optimization result of orthogonal experiments,the single factor experiments for changing F/M and improving reaction temperature are taken and the optimization preparation parameters and formulations of the resin were obtained as follow:reaction temperature is 90℃,pH=9.0,F/M=2.8,the content of caprolactam is 14.0% of melamine mass. Under the optimized preparation parameters and formulations,the viscosity of the prepared MF resin is 1 547.5 mPa·s,the solid content is 70.5%,the storage time is 76 h,and the foaming preporties of the MF foam plastic is good and the apparent density of the MF foam plastic is 32.76 kg/m3.%将甲醛溶液和多聚甲醛按质量比1:1与一定量的三聚氰胺、改性剂(聚乙二醇200、己内酰胺、一缩二乙二醇、乙二醇)在一定的反应条件下制得可发性改性三聚氰胺–甲醛(MF)树脂,并在80℃下对其进行发泡制备泡沫塑料.采用正交实验考察了反应温度、pH值、甲醛/三聚氰胺物质的量之比(F/M)、改性剂种类及其用量对改性MF树脂固含量、黏度、储存期以及泡沫塑料表观密度的影响,在此基础上通过改变F/M、提高反应温度等单因素实验确定了制备可发性改性MF树脂的适宜优化工艺及配方,即反应温度90℃,pH=9,F/M=2.8,改性剂己内酰胺用量为三聚氰胺质量的14%.在优化工艺及配方下得到的改性MF树脂溶液黏度为1 547.5 mPa·s,固含量为70.5%,储存期76 h,改性MF树脂发泡性能优良,发泡后泡沫塑料的表观密度为32.76 kg/m3.
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