Abstract
The concentrations of surfactant and oil, emulsifying method, and interfacial tention were examined as the possible factors affecting the stability of liquid petrolatum-water emulsions stabilized with mixed surfactants of sorbitan monolaurate and polyoxyethylene sorbitan monolaurate in its relation to hydrophile-lypophile balance (HLB) value. The so-called "optimum HLB value" is obtained by the water phase separation test. This is closely related to the particle size and flow properties, but has little or no relation to the properties of interfacial film. On the other hand, oil phase separation test can be considered to evaluate the coalescence of oil droplets in relation to the properties of interfacial film. Change in the surfactant composition affected oil phase separation in relation to the interfacial tention. The conventional screening method for emulsifying agants by the HLB concept was criticized on the basis of the present investigation.
