Accelerated test method for dirt pick-up resistance
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 optimisation. 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.
A team of researchers 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. 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.
The study has been published in Journal of Coatings Technology and Research, Volume 18, 2021.