一种Co/Ca复合催干水性醇酸树脂防腐涂料的制备

Preparation of waterborne alkyd resin anticorrosive coating by Co/Ca composite drying

以氢氧化高钴[Co(OH)3]和Ca(OH)2为原料混合形成Co/Ca复合催干体系,制备水性醇酸树脂防腐涂料。结果表明:该涂料的表干时间小于8h,实干时间小于24h,挥发性有机物含量(VOC)较低,小于37g/L,远低于标准300g/L的要求,耐水性及耐盐水性好,工程应用效果理想;机理分析表明,当用氨水调节pH为8.5左右时,Co3+和氨水形成Co3+(NH3)6络合物,在涂膜形成后,氨水挥发,Co3+被释放,与水性醇酸树脂中的脂肪酸根阴离子基团(Ln-)结合,发生催干反应,形成ConL3缔合物;Ca(OH)2中的OH-生成水,在涂膜干燥过程中挥发离去,Ca2+与Ln-形成CanL2缔合物,从而起到对水性醇酸树脂的辅助催干。

A waterborne alkyd resin anticorrosive coating was prepared by Co/Ca composite drying system,which formed by Co(OH)3 and Ca(OH)2.The results showed that the surface drying time of the coating was less than 8 h,and the dry time of that was less than 24 h.The Volatile Organic Content(VOC)was low,which was only 37 g/L and far below the standard requirements of 300 g/L.Its water resistance and salt water resistance was good,and the effect of engineering application was ideal.The mechanism analysis showed that when the pH was about 8.5 adjusted by ammonia water,there was a Co3+(NH3)6 complex that formed by Co3+and ammonia.After the coating film formed,the ammonia was volatilized and Co3+was released.Co3+was combined with the fatty acid anion group(Ln-)in the waterborne alkyd resin to cause a reaction and form a ConL3 associate.In Ca(OH)2 solution,the OH-formed water that evaporated and left during the drying process of the coating film.Ca2+was combined with Ln-to form a CanL2 associate to act as an auxiliary drying of the waterborne alkyd resin.