(115b) Study on Frictional Property of Powder for Cosmetics

Having a pleasant feel is one of the most essential factors in cosmetics. There are many kind of physical properties which create a favorite feeling when touched, but at first we decided to pay our attention to the frictional property of powder. A new type of the friction tester for powder cosmetics was proposed.The principle of this tester is measurement of the tension force for a single fiber or a wire during sliding in the compressed powder bed (single-wire-sliding-type tester). The friction characteristics represented as the relationship between the pressure of powder bed and the tension force was measured easily using relatively small amount of sample. The sensitivity, reproducibility of data and high resolving power for this tester were confirmed by measuring the cosmetics powder materials. As an application, the evaluation of the smooth feeling for powders was demonstrated comparing with the result of human sense. The frictional property of cosmetics materials like flake powder can be evaluated.