For the last century, titanium dioxide (TiO2) remains the immutable material in paint and coatings. Naturally occurring, finite, and without a synthetic substitute, its opacifying effects are irreplaceable (whiteness and refractive index value). Paradoxically, these same benefits produce negative outcomes in both economy and environment through high cost in formula and carbon footprint intensity. Rooted in traditional formulaic solutions unable to control the effect of diminishing returns that TiO2 inherently yields, chemists can only load so much before the benefit-to-cost ratio becomes untenable.
An article in PCI from January 7, 2022 by Dr. Michael Diebold, a former Research and Technical Fellow at Dupont and Chemours, emphasizes this inherent behavioral truth; “The opacity benefit of TiO2 decreases as TiO2 levels increase, and there is an upper limit where adding too much TiO2 can even become detrimental to the overall light scattering power of the paint. In such cases, the only way to achieve complete opacity is to increase the thickness of the paint film.”