Surface Treatment of Pigment Red 3 Using Surface Sulfonating Method and Study its Properties in Water Based Flexography Inks

In this research, pigment red 3 was treated using sulfonation method. The untreated organic pigments have low surface free energy. With this treating method the surface free energy of pigment increases. The aim of this study is surface modification of pigment red 3. The treated pigment showed very good dispersibility and dispersion stability in aqueous media. The dispersion of these particles in organic polar media are stable and without aggregation. After treating, the polarity of particles increased, show manifest dispersability in polar media. Parameters such as time, temperature, solvent/pigment ratio, acid/pigment ratio were considered as independent parameters at taguchi method. For obtaining standard array, for each parameter four levels were considered. The proffer array with taguchi method was L16. After the design of experiment, the treated and untreated pigments were formulated in water based flexography ink. In order to assess the inherent and application properties of treated pigments and selecting the suitable samples, examinations such as pH, fineness, rate of dispersion, gloss, tinting strength and chroma were performed. Also according to the results of analysis of variance, the effect of each independent parameter on studied properties was considered. J. Color Sci. Tech. 7(2013), 93-102©. Institute for Color Science and Technology.