The Effect of Pigment Concentration and Particle Size Distribution on the Rheological Behavior of Lithography Inks

In this research, a lithography ink formulation based on the Maleic and Alkyd resin has been prepared and its rheological parameters such as viscosity vs. shear rate, thixotropy cycle, storage and loss modules and dynamic viscosity were studied. It was observed that viscosity values augmented severely by increasing the pigments concentration and reducing the particle size distribution. Time dependence thixotropy values were significant in samples containing small particle size and high pigment concentration. Structural networking and association of carbon black particles as well as particle-particle and particle-binder interaction are reasons for this behavior. Storage and loss modules were increased with reduction of particle size and/or increasing of pigment concentration. Besides, the differences between dynamic parameters in low frequencieswere obvious. J. Color Sci. Tech. 4(2010), 91-103© Institute for Color Science and Technology.