汽车高装饰性涂层在国内典型气候中的耐候性表现及分析

目的选择合适的试验条件和方法提高汽车涂层的耐候性。方法对比世界公认的汽车环境试验基准站的气候条件,分析国内环境试验站进行自然曝晒试验的条件,进一步分析人工加速老化试验和户外自然曝晒试验之间的规律性和相关性,分析不同底材相同涂层的耐候性表现,提出了对汽车高装饰性清漆及涂层的耐候性质量控制的建议。结果在失光率方面,人工加速老化试验3000 h与琼海(湿热)和敦煌(干热)地带自然曝晒12及15个月的结果的相关性较差(均小于0.8),与江津(酸雨)和漠河(寒冷)地带自然曝晒12及15个月的结果均出现负相关性,数据波动较大。结论对于考核汽车高装饰性涂层的清漆,人工老化试验建议3000~5000 h。自然曝晒试验至少应选择干热和湿热两个地域,时间至少为2年。由于汽车产品的特殊性,进行人工加速老化试验时需重点关注:1试验条件的选择;2试验过程要强化水分子对涂层的渗透作用;3试验要模拟昼夜温差变化。

Weather Resistance and Analysis of Automobile Decorative Coating in Typical Domestic Climate

The work aims to improve weather resistance of automobile coatings by selecting appropriate test conditions and methods. Universally accepted environmental benchmark test stand conditions were compared, natural exposure test conditions of domestic environment experimental station were analyzed, regularity and correlation between artificial accelerated aging test and natural outdoor exposure test were further analyzed, weather resistance of same coating with different substrates, and sug-gestions on quality control of high automobile decorative varnish and coating were proposed. In terms of light lost rate, 3000 h artificial accelerated aging test had poor correlation with 12 & 15 months natural exposure in Qionghai (damp and hot) and Dunhuang (dry and hot) (both<0.8), and negative correlation with 12 and 15 months natural exposure in Jiangjin (acid) and Mohe (cold) with great fluctuation data. 3000~5000 hours artificial aging test is recommended to inspect automobile decorative coating varnish. At least two damp and hot as well as dry and hot zones are selected for natural exposure test to be conducted for at least 2 years. Due to particularity of automobile products, the artificial accelerated aging test shall focus on: (1) selection of test conditions; (2) strengthening permeation of water molecules to coating, humidity control and guarantee the moisture content in the coating in the coating during the test; (3) simulating day and night temperature difference change.