Titanium Dioxide UV Absorption

The main difference between ultrafine and pigmentary titanium dioxide is their crystal size. The crystal size of pigmentary titanium dioxide is about 200 nm and that of ultrafine titanium dioxide is about 20 nm. The optical properties of these two titanium dioxides are different.

The 200 nm crystals scatter visible light most efficiently, imparting good hiding power, whereas small, 20 nm crystals of ultrafine titanium dioxide scatter and reflect UV-light effectively and transmit visible wavelengths, which is why ultrafine titanium dioxide is transparent. To be useable in effect pigment or UV-absorber applications, ultrafine titanium dioxide must have a crystal size and crystal size distribution within exacting tolerances. Only then the best transparency will be achieved.

UV-TITAN is composed of both spherical and needle shape crystals, of which the later imparts the best transparency. The smaller the crystal size the lower the wavelength of the maximum UV-absorption.