新型光稳定剂产品应用于水性醇酸涂料的研究

醇酸树脂普遍应用于工业涂料,其暴露在自然太阳光时,容易造成外观上颜色的变化和涂层劣化与粉化,目前这层保护主要是添加紫外线吸收剂(UVA)和酸性系统使用受阻胺光稳定剂(N-OR HALS)来达成。由于环保趋势,水性醇酸涂料已发展成为解决有关一般常用传统高VOC溶剂型涂料,它能够有效减少或不使用溶剂的优点,而环保型涂料所遭遇的挑战之一,是需要光安定剂来保护涂料预防光劣化产生。先针对2种不同类型水性受阻胺光稳定剂N-R HALS(高碱性)和N-OR HALS(弱碱性)混合水性醇酸涂料测试,试验结果显示:N-OR HALS适用于水性醇酸涂料系统。本文主要是有关于应用试验设计(DOE)试验手法,根据实验室人工加速老化试验结果显示,增加水性紫外线吸收剂Eversorb AQ6和水性受阻胺光稳定剂(NOR-HALS)Eversorb AQ5在水性涂料中的有效浓度,可以增强相对的保护效果,试验数据显示膜厚对减缓黄变影响而言也是显著因子,但效果不如添加水性光稳定剂产品有效。

Study on Applications of Novel Light Stabilizers Used for Waterborne Alkyd Coatings

Alkyd resin is widely used in industrial coatings. Despite the advantages of these properties there is one major drawback with using alkyd resins. Discoloration and coating film degradation and chalking may occur over a relatively short period when alkyds are exposed to Ultra Violet （UV） light radiation from natural sunlight. The clear coat containing UV absorbers and light stabilizers （N-OR HALS） is commonly applied to the surface for protection. Waterborne alkyd coatings-the green coatings - have been developed to replace conventional alkyd coatings without VOC emissions. It could be a challenge when light stabilizers are re- quired to protect coatings to UV degradation.This paper is a comparison study of two different waterborne light stabilizers which are N-R and N-OR HALS mixed with waterborne alkyd coating. N-R HALS is high basic and N-OR HALS is weak basic. According to our test, N-OR HALS is suitable to use in waterborne acidic alkyd coating. Design of Experiment （DOE） was used in this study. Eversorb AQ6 is waterborne UV absorber and Eversorb AQ5 is N-OR HALS that was investigated in this model. The results confirmed that by increasing the concentration of Eversorb AQ5 and Eversorb AQ6 in the top coat can effhctively protect from UV light degradation. Furthermore, data also showed that by increasing the coating thickness, the weatherability of coating can＇t also be improved to some degrees.