Abstract: In this work,the application of rheological properties in the production process of O/W-based emulsion cosmetics has been studied.The macroscopic rheological properties and micro-rheological properties of the emulsion system under different emulsifying time were tested to obtain the time required for the mass production to reach the emulsion endpoint.The results show that with the increase of emulsifying time,the investigated O/W system presents weaker thixotropy and viscoelasticity,lower elasticity index (EI) values,lower macroscopic viscosity index (MVI) values and higher solid-liquid balance (SLB) values.When the emulsifying time is more than 10 min,the rheological parameters of the system no longer change with the increase of time,indicating that the system reaches the emulsion endpoint.In the determination of the emulsion endpoint,the micro-rheological properties obtained by dynamic light scattering theory are consistent with the macroscopic rheological properties obtained by conventional mechanical methods.Moreover,the micro-rheometer possesses the advantages of fast testing speed,high accuracy,small sample amount and no damage to samples,which is expected to expand the application in the production process of O/W-based emulsion.

Key words: cosmetics, O/W-based emulsion, rheology, micro-rheology, emulsion