The invention relates to a preparation method for special
pigment for aqueous
printing ink. The method comprises the following steps of: (1), preparing diazotization liquid by a diazotization process for later use; (2), preparing
coupling fluid; and (3),
coupling, namely a, adding the diazotization liquid into the
coupling fluid at the flow speed of 25 minutes, and controlling the pH value to be 10 and the temperature to be below 15 DEG C; b, continuing stirring for one hour and adding
rosin fluid; c, reacting for 60 minutes and then adding 60 kilograms of 95 percent
anhydrous calcium chloride; and d, raising the temperature to 85 DEG C after one hour, adding 40 kilograms of
strontium nitrate dissolved with water with the temperature of 70 DEG C, raising the temperature to 90 DEG C, regulating the pH value to be 6 to 6.5 by using
aluminum sulphate fluid, adding 7 kilograms of dissolved
rosin amine, stirring for 60 minutes, and filtrating, rinsing,
drying and crushing. The method has the advantages of use of aqueous
solvent, simple process and low cost. Furthermore, the environmentally-friendly aqueous
printing ink has low
mammalian toxicity, no
pollution, good flocculability, and good stability in an
aqueous medium.