Investigation of the relationship between measured paint properties and leveling

 
The interplay of a variety of physical influences forms the surface structure of a painted film, e.g., the superposition of droplets during spray application, the surface tension-driven leveling and changing rheological properties in the leveling phase. The presentation shows a method to predict the leveling behavior from measured paint properties using a numerical simulation program. Since the method considers thixotropy and viscoelasticity simultaneously, it is applicable to all commercial liquid paints. Latest ideas, how to consider evaporation and crosslinking in the simulations, are presented. By using the method the number of application experiments during paint development is reduced and raw materials can be chosen more specifically than in the past. In particular, the program reveals how the rheological properties must be changed in order to control the proportion of long-wave and short-wave structures. Finally, special phenomena such as airflow and Marangoni effect with/without leveling additives are studied.