Fine particles can be obtained with high pressure emulsification device. Combination of this device and the formulation technology to decrease interfacial tension between oil and water makes it possible to refine the oil particles dispersed in water to 1/30 to 1/500 (minimum size: 30nm) of the ordinary emulsion size. This technology achieves transparent liquid lotion having the same formulation as that of moisturizing rich cream.

This is the photograph of the emulsions of almost the same formulation. The left one with white appearance was the emulsion prepared by conventional method while the middle one of exactly the same formulation as the left one was manufactured by a high pressure emulsification device. The right one with transparent appearance of most suitable formulation was prepared by high pressure emulsification device with creatively devised order of addition.

This technology makes emulsion transparent and remarkably reduces its viscosity. Due to this, we can completely control the appearance and viscosity of the emulsions with the same water/oil ratio.

Shiseido developed an “O/W/O type” emulsification technology in which even finer oil particles are engulfed by water surrounded by an outer oil phase, and put it into a product. Such emulsification is called “multiple emulsification”. We developed this technology by focusing on the fact that the stability increases when unstable pharmaceutical agents are contained in the oil particles located in the innermost part. For preparation, an O/W emulsion, in which oil particles of a very fine size are used, is emulsified into another oil phase. This technology achieved unique characteristics including the texture that dramatically changes upon application to skin.

従In the past, water droplets were easily coalesced and maintaining stability was difficult in W/O emulsification where oil surrounds water. Shiseido conducted screening on various surfactants. As a result, we discovered that we can stabilize a large amount of water particles (maximum 97%) in a small amount of oil if we use a surfactant that forms “Bicontinuous Cubic Liquid Crystals” by blending it with water, and we named this emulsification “Hyper internal phase W/O emulsion”. This formulation produces the light texture without the unique oiliness and stickiness of W/O emulsification as well as effect for maintaining moisture and flexibility of the skin.

Thickeners including water soluble polymer are often used in cosmetics. Their functions are as follows and their properties are very important.

The point for achieving highly thickening effect from microgels is to prepare as small particles as possible. In order to achieve this, we decided to obtain superfine water-swellable microgels using inverse microemulsion polymerization.
In the 3 ingredient system of water-oil-nonionic surfactant, O/W emulsion and W/O emulsion are formed at low temperature and high temperature (border line: phase inversion temperature, PIT) respectively. On the other hand, interfacial tension reduces up to the limit around the PIT; therefore, even with mild stirring condition, extremely superfine emulsion is automatically generated. This method which utilizes this phase as a polymerization is called inverse microemulsion polymerization method.