货车用水溶性预涂底漆工艺试验研究

Test Study of Manufacturability for Water-soluble Pretreated Primer for Wagons

针对溶剂型预涂底漆在货车用钢材涂装过程中大量挥发性有机化合物(VOC)排入大气中,经常发生VOC排放超标,给大气环境带来污染的问题,提出采用VOC含量比较低的水溶性预涂底漆。由于目前还没有统一的铁路货车用水溶性预涂底漆产品标准,导致各生产企业水溶性预涂底漆的产品性能及工艺性各不相同。因此,经过调研比较后选定某水溶性预涂底漆,对其喷涂、切割、折弯和焊接工艺性进行试验,并根据试验结果调整预涂底漆配比和喷涂工艺参数。对调整后的水溶性预涂底漆进行小批量试用,其干燥时间、附着力和漆膜厚度等参数基本满足要求。指出当环境温度低于5℃或相对湿度高于70%时,喷涂前需预热钢材;温度低于20℃或相对湿度高于70%时,喷涂后需烘烤;当遇到钢材表面锈蚀严重或有油污等杂质时,需清除干净后才能喷涂水溶性预涂底漆,否则影响漆膜质量。

A great quantity of volatile organic compounds (VOC) coming from solvent-type pretreated primers are released to the atmosphere during painting,thus leads to VOC emission exceeding the allowed figure. This brings a pollution issue to the atmospheric environment. Therefore,the article proposes to apply a water-soluble pretreated primer containing relative low VOC instead. Since there is no unified standards available for water-soluble pretreated primers used for railway wagons,the product performance and manufacturability of different water-soluble pretreat. ed primer manufacturers are varied. Therefore,upon investigations and comparisons,the water-soluble pretreated primer of a manufacturer is selected,sprayed,cut,bent and welded,then with a manufacturability test carried out. According to the test results,the proportioning of pretreated primer and the technological parameters for spray coating are adjusted. The adjusted water-soluble pretreated primer is tried out in a small batch,with its drying dura. tion,adhesion,film thickness and other parameters generally meeting the requirements. Finally,the article propos. es to preheat the steel when the ambient temperature is lower than 5 ℃ or the relative humidity is higher than 70%;to dry after spray coating when the temperature is lower than 20 ℃ or the relative humidity is higher than 70% eliminate the corrosion,oil stain and other impurities before spraying the water-soluble pretreated primer when the steel sur. face is gravely eroded or oil stain and other impurities exist,otherwise,the film quality will be affected.