Preparation method of organic pigment easy to disperse in plastic

The invention relates to a preparation method of an organic pigment easy to disperse in plastic. The method comprises: pulping and dispersing an organic pigment filter cake in water to generate slurry with high solid content and mass fraction of 15-30%; adding a surfactant, mixing, and grinding by a sand mill to reduce the particle size of pigment particles to be less than 200 nm, wherein the diameter of a medium used by the sand mill is 0.2-0.8 mm, and the addition amount of the surfactant is 5-15% of the mass of the pigment; and carrying out spray drying on the dispersed slurry to prepare loose organic pigment dry powder. According to the invention, the coloring strength of the product obtained by the invention is increased by 18-28% in plastic detection. during plastic processing, the filter pressing value of the product is less than 0.4FPVbar/g, and the filter pressing value, obtained by a conventional method, of the product is more than 1FPVbar/g. The pigment developed by the invention is very suitable f