Colour change in exterior wall paints

 
The main reason of colour change is the increase in optically active boundary surfaces during weathering. A simple formulation principle can be derived from this effect: To delay the time at which an increase in optically active boundary surfaces sets in. The titanium dioxide pigments in the formulation play a key role. A highly weatherresistance TiO2 is a basic prerequisite. But it works only in combination with other premium raw materials. The first are hard, non-tacky, highly weather-resistant polymerdispersions. Also the use of extenders, which should be as inert as possible. The type of formulation is another critical factor. Paints formulated above the CPVC show a tendency of fine colour pigment particles leaching. Only the knowledge of all this numerous factors influencing colour change will help to increase sustainability by supporting longer renovation intervalls.