Dirt pick-up is a long-standing issue for exterior architectural coatings. Dirt pick-up resistance (DPR) is highly sought by end users, and significant resources have been committed by paint manufacturers to improve it. The task is complicated by the multitude of regional and local factors such as seasonal weather, intensity of economic activity, or atmospheric particle burden. Typically, paint manufacturers try to control DPR via careful selection of additives and formula optimization. Testing the new formulas in real time is long and, therefore, there is a clear need for a faster and more reliable test that takes into account the key elements of the dirt pick-up mechanism: particle transport, adhesion, and release to/from the surface. Our team has developed an accelerated test that focuses on thermally driven adhesion and takes a fraction of the time necessary for outdoor exposure testing. The test correlates well with early outdoor exposure results when formulation parameters are controlled and when there are moderate-to-large performance differences among paint formulas. The test was used to improve the accelerated DPR of a paint formula, which subsequently was verified against real-time outdoor exposure in three geographic regions with different climates and airborne particulate pollution levels.

沾污是室外建筑涂料的一个长期问题。耐沾污性 (DPR) 受到最终用户的高度追捧，油漆制造商已投入大量资源来改进它。由于季节性天气、经济活动强度或大气颗粒负荷等多种区域和地方因素，这项任务变得复杂。通常，涂料制造商试图通过仔细选择添加剂和优化配方来控制 DPR。实时测试新配方的时间很长，因此，显然需要一种更快、更可靠的测试，该测试考虑到灰尘拾取机制的关键要素：颗粒传输、粘附和释放到/从表面。我们的团队开发了一种加速测试，专注于热驱动附着力，只需花费户外暴露测试所需时间的一小部分。当配方参数受到控制并且涂料配方之间存在中到大的性能差异时，该测试与早期户外暴露结果相关性很好。该测试用于提高涂料配方的加速 DPR，随后在具有不同气候和空气颗粒污染水平的三个地理区域进行了实时户外暴露验证。