The invention discloses a preparation method of a
pigment used for nitrocotton
solvent ink, which comprises the following steps: beating 800 parts of water, 98 parts of
hydrochloric acid and 60 parts of 3,3'-dichlorobenzidine, adding 132 parts of
sodium nitrite solution at the temperature below -3 DEG C, stirring at the temperature of 0 DEG C, regulating the end point with
sulfamic acid until KI
starch test paper is slightly blue, and adding
activated carbon and
red oil solution to obtain a solution I; adding 19.4 parts of
acetic acid and 2-60 parts of 12-hydroxy
ammonium stearate in 350 parts of water, heating to be transparent, regulating water to reduce the temperature, and filtering the solution into a
coupling tank; dissolving 136 parts of
sodium hydroxide and 102 parts of AAMX in 800 parts of water to be transparent to obtain a solution II; adding the solution II into an
acetic acid solution for anti-acidification, and stopping acid eduction when the pH is 4.8 to obtain a solution III; combining the solution II and the solution I into the solution III to couple for 50-60 minutes, convecting and adding
convection alkali when the pH is 4.5 until
coupling is ended, raising the temperature to 95 DEG C, adding 200 parts of
sodium hydroxide, adding 5-52.5 parts of
rosin solution, adding 100 parts of
hydrochloric acid, regulating the pH to 5, adding 2-30 parts of WB-101, stirring, reducing the temperature below 60 DEG C, filtering by pressing, flushing, and
drying to obtain the
pigment used for nitrocotton
solvent ink. The nitrocotton
solvent ink prepared from the
pigment used for solvent ink has low
viscosity, high gloss, high transparency and high strength.