Titanium dioxide (TiO2) is used in a variety of personal care products, including sunscreens, pressed powders, and loose powders, as a UV filter or whitening agent. In lotions and creams (dermal exposure), it is not a risk for adverse health effects. However, when titanium dioxide is inhalable—as it may be when in powder form—it is considered a possible carcinogen by the International Agency for Research on Cancer.Titanium dioxide nanoparticles do not appear to confer any unique health hazards.
In addition to consistency, manufacturers must also consider the cost implications of buff percentage. Higher levels of coating on titanium dioxide particles can increase production costs, as more coating materials are required. However, a lower buff percentage may lead to a lower quality product that does not meet the needs of customers. Balancing the cost and quality considerations of buff percentage is a key challenge for manufacturers in the titanium dioxide industry.
Zinc oxide. Zinc oxide is a popular cross-linking agent for rubber and for various resins. It is essential in the formulation of solvent-borne polychloroprene adhesives. Furthermore, zinc oxide is a good UV stabilizer, has biocidal activity and has a relatively high refractive index (2.0) which makes it an efficient white pigment. Some typical properties are: density 5.6 g/cm3; particle size 0.036-3 μm; oil absorption 10–20 g/100 g; specific surface area 10–45 m2/g. Zinc oxide is produced by reaction of the metal in the vapour state with oxygen. Zinc oxide is nonporous and is quite pure. Thus, the high surface area of some grades is due to the small particle size of zinc oxide. Some grades, especially for use in the rubber industry, are surface modified by deposition of 0.2-0.4% of stearic acid, propionic acid, or light oil [47].