Cosmetics contain many types of powders. For example, pigments used in makeup cosmetics mainly control visible light, and UV scattering agents used in UV-preventing cosmetics mainly control ultraviolet light. In addition, powder is used for body odor prevention and skin care.
The surfaces of such powders can be designed in order to provide and improve both these individual and composite effects.
Furthermore, since powders are often dispersed in cosmetic emulsification systems, the surface is designed to be hydrophilic / hydrophobic and dispersed in the desired phase to improve the feeling of use and makeup durability.
In this review, the outline of the surface treatment method of powder used in cosmetics and specific examples of surface design are reported.
Ultrafine particles have recently been expanded to cover many applications and industries. For practical use of ultrafine particles, the control of dispersion is one of the important factors because those particles tend to aggregate spontaneously. Since secondary aggregations sometimes induce unfavorable property changes, the authors have been applying high-speed mixing processes as one of the approaches to eliminate unfavorable aggregations of particles. We show here the recent examples of the applications of a thin-film spinning mixer for the preparation of monodispersed aqueous dispersions together with examples of the improvement of dispersion stability and light scattering properties.
Estimation of the fine particle dispersion in polymer composites is an important technique for developing novel functional materials. In this paper, a statistical model on fine particle dispersion in suspension systems is introduced. The model was developed from Usui's model based on the population balance of the fine particle clusters. The new model can be applied to suspensions by considering the size distribution of clusters in a flow field. The computational load is as low as for computational fluid dynamic methods. Thus, it is a promising method for actual process systems.
Ballpoint pens are very familiar products in people’s lives. Moreover, in recent years, their range has become larger and more gorgeous than before. These ballpoint pens have evolved with features and functions depending on the intended use and their various performances stimulate user preferences. They now have a choice of various ballpoint pens to suit their use.
In this review, I will explain the basic principles, structure, type, and evolutionary process of the ballpoint pens that we use. Furthermore I will introduce the “smooth oil-based ballpoint pen” that has evolved in recent years and explain why this product was able to demonstrate innovative performance compared to other ballpoint pen products.