Abstract
Because of the concern of many consumers, it is important to study make-up deterioration, which is a phenomenon in which foundation falls into wrinkles with time. Nevertheless, few studies on that deterioration have been carried out so far. Aiming for development of a base make-up preventing the deterioration, we investigated in the following three steps. In the first study, from a survey and visual observation of ladies'faces, we clarified the mechanism of the deterioration around the smile lines, which was caused by two factors,“coming-off”and“agglomeration”of the powders in the foundation after wetting with sebum and being moved into wrinkles by facial movements. In the second investigation, based on the above-mentioned mechanism, we reproduced the deterioration in vitro and developed a method of quantitative evaluation of“agglomeration”and“coming-off”of the powders in the foundation by using histogram analysis. In the third study, using this method, we evaluated various cosmetic raw materials and found a superior combination of elastic polymer and high molecular weight silicone. By using this combination, we formulated the make-up base. This make-up base was confirmed to be long-lasting around smile lines.
