抄録
In this study, a microemulsion (ME) phase containing silicone oil was prepared, and its detergency was investigated. Decamethyl cyclopentasiloxane (DC), a good solvent for silicone soils, was combined with cosmetic grade alkyl type surfactant, polyoxyethylene (8 mol) glyceryl monoisostearate (PGMI), and ethanol aqueous solution to prepare the ME phase. The relationship between the structure of the surfactant aggregate and detergency of cosmetic soils containing silicone resin was investigated. The ethanol concentration dependence on the solubilization of DC (ME region) was similar to that of typical temperature dependence of hydrocarbon in nonionic surfactant aqueous solution. On the other hand, the solubilization behavior of DC differed from that of polar oil cetyl isooctanoate (CIO), which can be attributed to the miscibility with the alkyl type surfactant and the site for the solubilization in the micelle. Detergency of the cosmetic soils in a series of the ME solution indicated clear improvement with increasing aggregation number of the surfactant. From the results, it was shown that preparation of ME with large aggregation number such as bicontinuous phase containing DC could provide a good solution for cleansing silicone soils.
