阴极电泳涂料用树脂乳液的合成及泳透力研究

Synthesis and Throwing Power of Resin for Cathodic Electrodepostion Coatings

以低相对分子质量液体环氧树脂和双酚A为原料制备扩链环氧树脂,经有机胺胺化后,添加封闭型异氰酸酯固化剂,酸中和后,去离子水乳化制备阴极电泳涂料用乳液。对扩链环氧树脂的合成条件进行探讨,将阴极电泳涂料乳液与专用色浆配套,研究扩链环氧树脂的相对分子质量、酸性中和剂种类、沉积电压对阴极电泳涂料泳透力的影响。研究结果表明,扩链环氧树脂的最佳合成工艺条件为催化剂N,N-二甲基苄胺的用量为2‰、反应温度为140℃、反应时间为1.5 h,傅里叶红外光谱仪测试表明树脂合成成功。泳透力测试结果表明,要提高阴极电泳涂料的泳透力,扩链环氧树脂的相对分子质量范围在1 000-1 600,酸中和时选择酸性较强的酸,沉积电压宜适当提高。

The synthesis of emulsion for cathodic electrodeposition(CED) coatings using chain-extended epoxy resins, blocked polyisocyanate crosslinking agent and acid, etc. wherein the chainextended epoxy resins were prepared by liquid epoxy resin and bisphenol A. the synthesis conditions of the chain-extended epoxy resins are discussed. The effects of resin molecular weight, acid type and deposition voltage on throwing power of CED coatings were studied. The results show that the optimal synthesis conditions for the chain-extended epoxy resins are 2‰ N,N-dimethylbenzylamine,140 ℃ reaction temperature, and 1.5 h reaction time. The result from Fourier infrared spectrometer test indicates that the chain-extended epoxy resins are successfully synthesized. In order to improve the throwing power of CED coatings, the molecular weight of the chain-extended epoxy resins should be 1,000-1,600, meanwhile, the strong acid and high deposition voltage should be conducted.