Particle size and size distribution have great influence on whiteness and hiding power of tio2
The particle size and size distribution of tio2 will have an effect on the whiteness. The particle shape of titanium dioxide requires a smooth profile without edges and corners because the angular surface weakens the reflection of light. The particle size should be controlled between 0.2 and 0.4 μm. That is equivalent to half of the wavelength range of visible light (0.4 ~ 0.7μm), so as to obtain high light scattering ability, making its color appear whiter.
When the particle size is less than 0.1 μm, the crystal is transparent; when the particle size is too large, even if a small amount (0.1% to 2%) of large particles having a particle size of 0.5 μm or more is contained in the product, the particles will be reduced in light. Scattering power can have a very detrimental effect on pigment properties. For the particle size distribution, it is required to be uniform and the distribution band should be narrow.
