自愈合微胶囊在电泳涂料中的应用

目的提高阴极电泳涂料漆膜在受到外力损伤时的自愈合能力。方法采用原位聚合法,以KH-550改性环氧树脂为囊芯,以密胺树脂添加脲醛树脂为囊壁,形成耐化学性好和粒径小的微胶囊,并加入到阴极电泳涂料中,从而增加漆膜在受到外力损伤后的自愈合能力。通过偏光显微镜、SEM对微胶囊的粒径和形貌进行了表征,通过铅笔硬度测试、附着力测试、粗糙度测试、耐盐雾试验,分别评价了电泳漆膜的硬度、附着力、粗糙度、漆膜耐蚀性。结果在阴极电泳涂料中加入微胶囊后,槽液性能指标未受影响,漆膜物理机械性能基本未受影响,粗糙度由0.174变为0.201,标准磷化板在1000 h的NSS后,划叉处明显要好于普通漆膜的防腐性。结论以KH-550改性环氧树脂为囊芯,以密胺树脂添加脲醛树脂为囊壁的微胶囊,加入阴极电泳涂料后,有效提高了漆膜在受到外力损伤后的自愈合能力。

Application of Microcapsule as Self-healing Materials in Electrophoretic Coating

The work aims to improve the self-healing capability of cathodic electrophoretic coating subject to external damage. Microcapsules were prepared with melamine resin containing urea formaldehyde resin as shell material, and modified epoxy resin (KH-550) as core material by virtue of in situ polymerization. The microcapsules of good tolerance and small grain size were formed and added to the cathodic electrophoretic coating, so as to increase self-healing capability of the coating. The particle size and morphology of the microcapsules were characterized by means of polarizing microscope (PM) and scanning electron microscope (SEM). Hardness, adhesion, roughness and corrosion resistance of coating were evaluated by virtue of pencil hardness test, adhesion test, roughness test and salt spray test. The performance indices of bath solution as well as physical and mechanical properties of the coating were not affected when microcapsules were added to the cathodic electrophoretic coating. Roughness of the coating increased from 0.174 to 0.201, corrosion resistance at the cross was better than that of ordinary paint film after NSS 1000 h test on standard phosphating plate. Self healing ability of the coating subject to external damage can be increased effectively provided that cathodic electrophoretic coating is added to microcapsules prepared with melamine resin containing urea formaldehyde resin as shell material and modified epoxy resin (KH-550) as core material.