A Comprehensive Understanding of 'TiO2 Pigment Durability'
Coatings manufacturers consume nearly three million tonnes of TiO2 pigments globally every year - a clear indication of the importance of this opacifying pigment to this industry. This reflects the unsurpassed ability of TiO2 to uniformly scatter white light without absorption (which would lead to color). Virtually all coatings, except those that are clear or black, take advantage of the opacity of TiO2 as the primary or, in many cases, the only provider of hiding power. TiO2 pigments have a rich history in the coatings industry - a history that goes back over 70 years - and are certain to maintain dominance for the foreseeable future since there are no known not-in-kind replacements that approach the opacity of TiO2.
While the benefits that TiO2 pigments bring to coatings are significant, there are some situations where TiO2 can be harmful to important properties of the final paint film. Perhaps the most familiar example of this to many paint formulators - particularly those who work in the industrial and/or OEM finishes - is the detrimental effect of TiO2 on paint durability. This effect, commonly referred to as "TiO2 durability" (which is actually a misnomer, since the TiO2 itself is completely durable - and hence the quotation marks in the title of this paper), is well recognized in the coatings industry. What is less well understood is that TiO2 affects paint durability in a number of ways, both good and bad. In this paper we review the many ways that TiO2 can affect paint durability, and how the interplay ultimately determines the longevity of a paint film.