Looking beyond the obvious - morphology optimization of architectural paint

 
Most of us come in contact with a broad variety of Architectural Coatings every day - either in our own home environment or as exterior coatings on buildings. They typically fulfill various requirements regarding appearance as well as protective properties. Appearance requirements e.g., cover a broad variety of target gloss levels - as well as colors or haptic impression. During the last years, there is strong interest in very low gloss values - which is challenging to achieve especially concerning the 85° levels. One key lever can be the optimization of particle packages in e.g. wall paint formulations. Experimental data easily leads to the learning that interactions are complex, and it is difficult to foresee results when formulations are altered. Modern tools like 3D laser scanning microscopes allow us to assess surface morphology and topography in a time efficient way and a catalogue of surface morphology data helps to enhance understanding of component interactions. Since there are multiple parameters which can be varied like particle shape or size, this enhanced understanding speeds up formulation development. When it comes to haptic effects, topography is not the only determining factor, but chemical nature also plays a strong role - modified siloxanes, for example, can efficiently finetune surface slip. Thus, tribology assessment can be a very valuable addition to topography to understand 'touch and feel' results as well as 'scuff' resistance differences. The term scuff resistance is typically used to describe the properties of a wall paints related to wear marks e.g. from furniture or personal belongings coming in contact with the wall coating - limited resistance can easily destroy the appearance of a painted wall in daily use. Enhanced structural insights are also very helpful regarding mechanical resistance optimization. For low gloss formulations, often there is a huge challenge in avoiding so called 'burnishing' defect - which is the change (increase) in gloss after a wall paint is touched or wiped to remove some stains. Optimization of particle packages has a significant impact on mechanical robustness of wall paint formulations and microscopic analysis also helps to enhance understanding of mode of action. Since wall paints often need to fulfill a complex package of requirements, use of results from all mentioned areas can help to tailor the formulation and performance profile; examples will be shown during the presentation.