Sanyo Chemical Industries has developed Soliemer, a particle emulsifier for cosmetics that exhibits excellent formulation stability despite the absence of surfactants and provides a non-sticky smooth texture without creak. Soliemer is its original spherical silica with optimized size, shape, and surface modification. It improves the sensory perception of creakiness that has been a challenge to overcome with conventional Pickering emulsifiers and Soliemer provides highly stable emulsions with a smooth texture and excellent sensory.

Emulsification is a process in which one liquid is dispersed as small spherical droplets into another immiscible liquid, such as oil and water. Their uniformly dispersed state is called emulsion. The substance that acts at the interface of these two liquids to reduce the interfacial tension and create an emulsion is called an emulsifier. Many cosmetics such as milky lotions and creams, are made using with emulsification technology. Surfactants are commonly used as emulsifiers, but the use of the surfactants in cosmetic products may cause adverse effects, such as negative sensory sanitation of slimy feel and/or characteristic odor, and makeup-comes-off due to moisture such as perspiration. In addition, there are restrictions on the type of surfactant that can be used to obtain stable emulsions, depending on the type of oil.

On the other hand, Pickering emulsification is known as a useful emulsification method to overcome the above problems by using solid particles as emulsifiers without using a surfactant. Emulsions obtained by Pickering emulsification are more stable than those obtained by surfactant emulsification and are less likely to separate after emulsification. However, since cosmetic emulsions are usually very complex multi-component mixtures, even with Pickering emulsification, emulsification and post-emulsification stability in cosmetic formulations have sometimes been poor due to the influence of oil types and cosmetic ingredients. In addition, because the Pickering emulsifier is a solid particle, cosmetics using it have a powdery or creaky feel. Furthermore, there were handling difficulties due to the very fine particle size and uneven powder flowability of conventional Pickering emulsifiers.

Sanyo Chemical has developed a unique Pickering emulsifier Soliemer, a submicron size spherical silica whose size, shape, and surface structure are precisely controlled by utilising our expertise in surface control technology, to overcome the problems of creakiness and handling. Normally, it is difficult to obtain stable emulsions with particles of this size, but we have succeeded in obtaining stable emulsions by finding an optimal emulsification method for cosmetic formulations in addition to a surface treatment method for spherical silica. Soliemer is not easily affected by oil types or cosmetic ingredients and can maintain a stable emulsion for a long period of time in a relatively wide range of cosmetic formulations.

With these features, we believe that Soliemer can play an important role in a variety of cosmetic formulations to meet customer needs.