Measurement of drying rate of water-based coat with two volatile components by the temperature-change method

A commercial acrylic emulsion paint with added ethanol was prepared as a model paint with two volatile components. A convective batch-drying experiment of the model paint coated on an iron plate base was performed, and the temperature and weight changes of the coat were measured simultaneously. Basic equations of the temperature-change method derived for the volatile single-component system proposed previously by the authors were extended to give equations for two volatile components. Drying rates of water and ethanol of the coated model paint were successfully obtained by substitution of the temperature and weight changes of the coat into the extended equations. The method proposed in this study for measuring the drying rates of two volatile components is convenient in obviating the need for composition analysis of the drying vapor or drying coat. However, its use is restricted to cases in which the weight change of the drying sample can be measured successively with low air speed and air temperature, and cannot be applied directly to a system of three volatile components.