Experimental design was used to study the interactions of selected low cost emulsifier components and thus identify a crop oil concentrate emulsifier blend having optimum performance and low cost. For this study, the mixture variables included: nonylphenol + 6 EO, nonylphenol +10 EO, tall oil fatty aid (TOFA), and paraffinic petroleum oil. Water, although not an independent variable, was included as a coupling agent. The responses measured were number of phases, emulsion stability in soft water, emulsion stability in hard water, and emulsion stability in 2.5% ammonium sulfate solution, all at ambient temperature.
Using experimental design software, it is possible to visualize the interrelationships of the four components for each test condition, making it possible to predict the performance of any composition within the design space. After analyzing the response surface contour maps of the four-dimensional design space, we find that it is possible to formulate a crop oil concentrate that is single phase, offers very good emulsion performance in soft and hard water, and performs moderately well when tank mixed with ammonium sulfate solution. Coupling the performance data with a simple cost calculation, the formulator can select a composition that maximizes performance while at the same time minimizing cost.