Pigment dispersion: II

Any resin-solvent-pigment combination that can give a stable dispersion shows a minimum in the curve. Let us consider the significance of the minimum. To the right of the minimum, the viscosity of the external phase is increasing because the concentration of resin is increasing. As can be seen from equation (3), if h^sub e^ increases and the viscosity stays constant, then V^sup e^^sub i^. must decrease; that is, the amount of vehicle required per unit of pigment must increase.