Photo stable pigment containing composition

Abstract From the Canadian patent

Abstract, Paints and coatings involving semiconducting pigments such as titanium dioxide generally degrade because of oxidation of the binder by reactants that are photochemically produced on the pigment surface and, because of direct binder oxidation by charges that are photogenerated in the pigment. In titanium dioxide, this interaction is substantially reduced by avoiding reduced species and by introducing into the titanium dioxide trap states where photogenerated electron-hole pairs recombine by processes such as prolonged milling. Through these expedients a substantial increase, in the stability of the pigment containing composition is obtained.