Weathering – the property of polymer compositions to resist the destructive action of sunlight, rain, frost, snow, wind and other weather factors (such as gas and dust polluting the lower atmosphere). Surface treatment is needed to increase resilience. Inorganic (Al2O3, SiO2) increases the resistance of the particles of titanium dioxide to acid exposure, which may lead to the destruction of the pigment particles. Organic treatment improves the distribution of pigment particles in the bulk composition. Of special note is Titanium Dioxide 99.999% high purity grades 05/07 (TU-B-09-01-640-84), which is used in as a standard of purity, in the manufacture of optically transparent glass in fiber optics, electronics for piezoelectric ceramics, in the medical industry, etc. This is a particularly pure chemical substance, obtained by thermal hydrolysis. Technology of production of titanium dioxide pigments of titanium dioxide exists in two forms – anatase and rutile, and produced by two technological schemes: the chlorine and sulphate ways.
Both, anatase and rutile titanium dioxide may be produced in any way. Sulfate method was introduced in the industry in 1931, for the production of anatase form of titanium dioxide, and later, in 1941 – rutile. In this method, ore containing titanium (ilmenite, etc.) is dissolved in sulfuric acid, forming a solution of sulphate of titanium, iron and other metals. Then, in a series of chemical reactions, which include chemical recovery, purification, precipitation, washing and calcification, forming a core of titanium dioxide with the required particle size.