Siliconized acrylic dispersion binder extending the aesthetics & durability of façade coatings

 
Exterior thermal insulation composite systems (ETICS) are expected to have a long service-lifetime to compensate installation costs with gains through energy savings. The durability of the ETICS system is strongly affected by defects introduced through unfavorable moisture management. Moisture management is defined as balancing the water resistance and the "breathability" of the façade (Heilen & Künzel-Theory). The combination of silicone resin with acrylic dispersion binders has gained popularity due to their favorable moisture management properties. In these coatings, part of the acrylic binder is replaced with silicone resin to increase water-vapor permeability, while maintaining low capillary water absorption. This adaptation, however, leads usually to other limitations in the plaster or paint formulation, such as mechanical stability or longevity of façade appearance. We present technical challenges and investigations that led to the development of a new silane modified acrylic binder for extended durability of exterior coatings, specifically for ETICS application.