Titanium dioxide, also known as titanium(IV) or titania, is a
simple inorganic compound produced as a pure white powder with the chemical
formula TiO2. Generally, it is available in two main crystal forms, which are
rutile and anatase. Anatase is economical, easily dispersed in water based
systems, and a perfect opacifyer. Untreated titanium dioxide (anatase) has TiO2
with a refractive index of 2.55. However, it is not commonly used in exterior
(weather exposed) paint applications except for highway paints.
The sulphur process can produce TiO2 in both
forms, anatase and rutile.
1. Dissolving the raw material containing the titanium dioxide
in concentrated sulfuric acid
2. Precipitation of hydrous titanium dioxide from the acidic
solution by dilution and boiling (hydrolysis)
3. Leaching out of contaminants
4. Calcination (particle size increase) at temperatures of
5. Purification and subsequent coating of the pigment with
organic and inorganic oxides.
Paint and Coating
Titanium dioxide is one of the most widely
used white pigments because of its brightness and very high refractive index
(n=2.7), in which only a few other materials surpass it.
Titanium dioxide is an effective opacifier in powder form in
paper industry. It is employed as a pigment to provide whiteness and opacity of
paper products. Opacity is improved by optimal sizing of the titanium dioxide
particles. In addition to these effects a limited colour change is possible in
certain formulations depending on how and at which angle the finished product
is illuminated and have the thickness of the oxide layer in the pigment
In cosmetic and skin care products,
titanium dioxide is used both as a pigment and a thickener. In almost every
sunscreen with a physical blocker, titanium dioxide is found because of its
high refractive index, its strong UV light absorbing capabilities and its
resistance to discolouration under ultraviolet light. This advantage
enhances its stability and ability to protect the skin from ultraviolet light.
Sunscreens designed for infants or people with sensitive skin are often based
on titanium dioxide and/or zinc oxide, as these mineral UV blockers are less
likely to cause skin irritation than chemical UV absorber ingredients, such as
This pigment is used extensively in
plastics and other applications for its UV resistant properties where it acts
as a UV absorber, efficiently transforming destructive UV light energy into
TiO2 is also an effective
opacifier in powder form, where it is employed as a pigment to provide
whiteness and opacity to products such as paints, coatings, plastics, papers,
inks, foods, medicines as well as most toothpaste.