Pressure-sensitive adhesives(PSAs) are made by combining a tackifier dispersion and a natural or synthetic rubber latex. During the process of making the dispersion, a mixture of resins and rosin acids is melted, and it initially forms a water-in-oil emulsion. Water is then added continuously with constant agitation, the emulsion inverts to an oil-in-water system having micron-sized droplets. More water is then added to attain the desired concentration. To better understand the current process, we have developed an instrumented mixer and monitoring techniques to record as many process variables as possible; these include electrical resistance of the emulsion, agitator rotational speed, power consumption of the mixer and the flow rate of feeding water. In this paper, we identify all the factors which may influence the properties of the final product. On the one hand, our experiments show that the rpm of the outer impeller significantly affects the properties of the final product. On the other hand, the rotation direction of the two impellers and the rate of water addition after phase inversion do not influence the properties of the emulsion In addition, we find that increasing the speed of agitation does not necessarily lead to a smaller average dispersed phase size. On-line measurements show that when phase inversion is about to occur, power consumption of both impellers increases and then gradually decreases after phase inversion. These data indicate that the viscosity of the system reaches a maximum at the point of phase inversion. This finding appears to be in agreement with the published literature. Additionally, experiment data also show a large change in electrical resistance near phase inversion. Implications of all these results are discussed in the presentation.