A new tool to maximize the value of specialized TiO2 grade for flat paints

 
Hiding power is the primary benefit that TiO2 provides to paint by scattering the visible light, but as the distance between two TiO2 particles decreases, the particle scattering efficiency reduces significantly (Figure 1). This phenomenon is well understood and defined as the "crowding" effect. This explains the lower TiO2 efficiency at high TiO2 concentrations. Alternatively, spacing the TiO2 under crowding conditions will result in an increase in TiO2 efficiency and consequently hiding power. One way to create spacing is encapsulating the TiO2 particles in a thick layer, providing the necessary sterical hindrance. This can be realized by depositing engineered silica and alumina on the pigment surfaces to envelop them with a porous and voluminous coating (Figure 2). This thick coating functions as spacer keeping the TiO2 particles separated from one another, minimizing the overlap of TiO2 scattering volumes and improving the TiO2 scattering strength. These highly treated (HT) pigments have typically higher oil absorption than universal TiO2 grades, and this decreases significantly the critical Pigment Volume Concentration (cPVC).