Thermo-analytical characterization of pigmented waterborne basecoats

Modern waterborne basecoats contain a high degree of pigments to fulfill the wanted high brilliance and optical effects. Different kinds of pigment systems (color, pearl-effect, aluminum flakes) in a model binder matrix were investigated by Dynamic Mechanical Analysis (DMA) measurements at different pigment volume concentrations (PVC). To get more detailed information concerning the pigment binder interaction partially the binder system and the surface modification of pigments were varied. The results were correlated to technological tests (stone chip, adhesion). It can be shown, that special effects in waterbome basecoats like influences of resins or pigment-binder interaction can be investigated by means of DMA in a quite effective way. Thus it is possible to optimize one layer in a coating system in terms of its mechanical properties by reformulating the binder matrix and by a suitable surface treatment of the pigments.