Development of Long-Lasting Lipstick through the Molecular Design of a Novel Cross-Linked Silicone Resin

<p>One of the most effective techniques to improve the color transfer resistance of lipsticks has been to use a film-forming resin in combination with a volatile oil that covers the lips with a hard film. However, color retention is difficult because the film is brittle and easily peels off. Additionally, it tends to cause a dry feeling when the volatile oil evaporates from the lips. In this study, we have developed a novel silicone resin for use in lipstick products with a greatly enhanced flexibility and hardness that is impossible to achieve through a combination of conventional silicone resins. To assess the performance of our new silicone resin, its flexibility, hardness, and curing process were compared against those of conventional silicone resins. In addition, the effects of the molecular weight and structure of the developed silicone resin were also evaluated. Results showed that our silicone resin forms a very uniform film with a high hardness and flexibility compared to a conventional film. In addition, its molecular weight and crosslink density are shown to be important for improving the curing rate. In order to confirm the usefulness of the developed silicone resin, we prepared a formulation and conducted a color transfer resistance test, color retention test, and 12-hour long-lasting test. Results revealed that the formulation shows extremely high color transfer resistance and color retention. In addition, we performed a dry feeling evaluation and a shrinkage evaluation in which the formulation using our developed silicone resin was compared against a formulation using conventional film-forming agent combinations. Results revealed that the newly developed product had no film shrinkage and a significantly reduced dry feeling.</p>