Discussion on the use of nano materials continues unabated in the cosmetics world and in the media and the success of “microfine” titanium dioxide in sun-care has been overshadowed by concerns over the safety of nano particles. SCCS Opinion on Nano-TiO2 (22 July 2013 - SCCS/1516/13) has declared that Nano-TiO2 applied topically as UV-Filter is safe at a maximum use concentration of 25% in cosmetics, however some defined specifications have to be fulfilled, including:
•Purity of 99.5%
•Composition: rutile TiO2, or rutile form with max 15% anatase TiO2
•Photo-stable in formulations
•Low photo-catalytic activity (max 10% compared to non-coated or non-doped reference)
Unlike many competitive products, DSM’s highly successful microfine titanium dioxide sold as PARSOL® TX is greater than 99.5% purity in the rutile form and meets all the criteria required by the SCCS opinion. This allows formulators to use it with confidence in its safety and its outstanding performance as the inorganic UV-B filter of choice. (It also has some activity in the UV-A spectrum so useful in boosting UV-A rating!)
Extensive laboratory testing and formulating with PARSOL® TX shows that it is very easy to disperse in the oil phase of the emulsions, even with low shear, due to its highly hydrophobic surface treatment. This same surface treatment also almost guarantees that it will not react with other “sensitive” components of the formulation such as Parsol 1789 (BMDBM) which can commonly occur with some aluminium treated titanium dioxides, resulting in crystal formation and reduction in UV-A performance. The unique surface on PARSOL® TX treatment even allows compatibility with polyacrylate thickeners such as Acrylates/C10-30 Alkyl Acrylate Crosspolymer, to allow production of gel formulations.