Characteristics of polyglycerin copolymer type nonionic surfactants as cosmetic emulsifiers

Poly (glycerin) randam copolymer type nonionic surfactant was synthesized from fatty alcohol, tetrahydrofuran, and glycidol under Lewis acid catalyst. To investigate the usefulness of this type of nonionic surfactant as an emulsifier in cosmetics, the emulsifying properties were compared with poly (oxyethylene) alkyl ether. The HLB-values of the copolymers ranged from 7 to 30. This is the first nonionic surfactant that HLB-value cover untill 30. By using phase diagrams the reasons why the HLB-values of RnTxGy exceeded 20 were discussed. A lamellar liquid crystalline phase and O/W emulsions are formed by the addition of water to a W/O microemulsion in the RnTxGy system; whereas a W/O emulsion is formed by the addition of water to the W/O micromulsion in the RnEOx system. This difference of the solution behavior is the reason that RnTxGy gives a high HLB-value and fine O/W emulsions. The dermal and eye irritation levels of RnTxGy are lower than those of RnEOx. We conclude that RnTxGy is useful as an emulsifier for cosmetics. Contributed and accepted in the Journal of the Society of Cosmetic Chemists.