Tailoring TiO2 Treatment Chemistry To Achieve Desired Performance Properties
Although properties are listed separately, there is some influence of one upon the other.
TiO2 pigment properties are determined by the base pigment and finishing process. The base pigment is affected by the manufacturing process, the crystal structure, the particle size distribution and the additives during manufacture. The pigment produced in both the chloride and sulfate processes is also agglomerated during particle size development. Usually milling steps take place during the finishing process to produce a pigment with the best possible particle size. Finishing also includes an inorganic treatment and, for many pigment grades, an organic treatment step. During inorganic treatment, pigment properties are affected not only by the amounts of the various chemicals but also by the conditions under which the treatment is deposited. Temperature, pH, deposition rate, source chemicals and other factors can influence the morphology or crystal structure of the treatment layers. The morphology of the treatment layers can, in turn, have an effect on the final properties of the pigment.