双氰胺/环氧粉末涂料的研究

Study on dicyandiamide/epoxy powder coating

以E-12环氧树脂为基础树脂、双氰胺(Dicy)为固化剂、2-甲基咪唑(2-MI)为促进剂,并配以其他助剂,经熔融共混制备出双氰胺/环氧粉末涂料。考察双氰胺、2-甲基咪唑用量对固化反应、涂膜附着力及耐冲击性的影响,并确定了两者的较佳用量。利用非等温差示扫描量热法研究了环氧/双氰胺/2-甲基咪唑体系的固化反应,并通过动力学分析得出了理论固化温度等固化动力学参数。在此基础上,根据实验得到了较好的固化时间和固化温度。另外,根据Kissinger和Crane方程拟合了固化反应动力学方程。结果表明,涂膜附着力及耐冲击性随着双氰胺及2-甲基咪唑用量增加先提高后减小。双氰胺、2-甲基咪唑用量分别为环氧树脂用量的4.00%、0.40%时,体系固化温度较低,130.00°C下固化30 min所得涂膜综合性能最好。

A series of epoxy powder coatings were prepared by melt blending method with epoxy resins as matrix, dicyandiamide （Dicy） as curing agent, 2-rnethyl imidazole （2-MI） as accelerant, and other additives. The effects of the amounts of Dicy and 2-MI on curing reaction as well as the adhesion and impact resistance of the films were examined and the optimal conditions were determined. The curing reaction of epoxy/Dicy/2-MI system was studied using non- isothermal differential scanning calorimetry. The parameters of curing reaction such as theoretical curing temperature were obtained through kinetic analysis. On the basis of this as well as experiments, the optimal curing time and curing temperature were obtained. The kinetic equation was fitted based on Kissinger and Crane equations. The results indicated that the adhesion and impact resistance of the films are increased initially and then decreased with increasing amount of Dicy and 2-MI. The powder coating containing 4.00% Dicy and 0.40% 2-MI （based on the mass of epoxy resin） has a rather low curing temperature and their cured films present the best performance after curing at 130.00℃ for 30 min.