Abstract
Young ladies in their 20s, as the representative age group, have a strong wish for a foundation that can provide a beautiful finish with natural skin-transparency and can allow the finish to last longer. In response to this wish, we have attempted to develop an ideal powder material that can yield the dual function described above. Based on the fundamental knowledge of the physiological and optical characteristics of human bare skin, we designed an optimal microstructure for powder with an ideal optical character. A hybrid powder, which is interference-pearl type TiO2/mica powder covered with a fiber-type ZnO by a morphologically controlled technology, was synthesized. The powder has a dual function. As a physico-chemical function, the powder can absorb and solidify sebum with its nano-scale fiber-type ZnO (diameter: approximately 50nm) of which the microstructure is controlled at the crystalline level. As an optical character, the powder can reflect a diffuse interference red light with is generated from the microstructure of the powder surface. A foundation containing the powder (8w/w%) can maintain the initial natural finishing with a beautiful transparency and give a dryrefreshing feeling for a significant period of time through its physico-chemical ability to absorb and solidify sebum on the skin. Since this new hybrid powder provides an optical character and a useful physico-chemical character, it has proven to be a valuable cosmetic ingredient of base-makeup products.
