Viscoelasticity of Water/Isopropanol/Alkyd Resin Emulsions

During the lithographic process, the emulsification of the Fountain Solution in the Ink can produce drastic modifications of the viscoelastic properties of the latter. We decided to limit our preliminary studies on simple systems based on water-in-typical vehicles and characterize the resulting emulsions through classical viscoelastic parameters derived from measurements between 0.1 and 1000 Hz. The mechanism of relaxation of the water droplets is readily observed and correlated with the radius of the droplets and the interfacial tension. The introduction of inclusions of water in the oil matrix enhance the elasticity of the emulsion at low frequencies. The effect of volumic fraction of the water phase and of the presence of surfactants in the emulsion are also studied. The experimental results are compared with a theoretical model of the rheological behavior of emulsions.