Carnegie Mellon Logo

Improving the Fabrication Process for the Titanium Oxide Pigment Industry

Photo

Article Posted On 3/21/2016

In the United States alone, the titanium oxide pigment industry was valued at $4.4 billion in 2014. Titanium oxide pigments are ubiquitous; they provide the opaque white color in all paints, including lacquers and varnishes. They are used to add whiteness to papers, plastics, food, medicines and most toothpastes. And, they are used as a pigment and a sunscreen agent in cosmetic and skin care products. For most of these applications, however, a stable nano-coating on the pigment particles is essential for the pigment to function properly.

With PITA funding, Bethlehem-based Material Complexions, Inc. and Lehigh University researchers partnered to study the problem of "chalking" that often occurs when titania is exposed to sunlight or other UV sources, which causes the paint or coatings to degrade. This form of degradation is avoided by coating the particles with an impervious shell. They looked, specifically, at the stability of a particular coating material: silicon dioxide or silica, which is one of the most abundant materials on earth, found in sands, rocks and soil. Also, the most attractive coatings are based on oxides of aluminum and silicon. However, these coatings, which are generally in nanoscale, are not thermodynamically stable and often do not have very strong adherence to the pigment particles.

What the team found is that a particular formulation containing oxides of silicon and calcium was stable under the experimental conditions in the lab. Their work has also provided a framework for designing and fabricating such coating materials on titania for specific applications, rather than relying on the less efficient "trial and error" strategies that have typically been employed in this process.

Material Complexions, Inc., a material diagnosis and development company that was spun-off from Lehigh University specifically to speed up the commercialization of its applied research on grain boundary complexions, will apply the findings of this investigation to its continuing efforts to develop better performing and cost effective nano-materials.