Organic pigments are insoluble organic substances, which are usually added to the substrate in a highly dispersed state to color the substrate. The fundamental difference between it and dyes is that dyes can be dissolved in the dyeing medium used, while pigments are neither soluble in the medium in which they are used nor in the colored substrate. Many pigments and dyes have the same chemical structure. Different use methods can transform them into each other. For example, some vat dyes and sulfide vat dyes can be used as fiber dyes if they are reduced to leucosomes; If not reduced, it can be used as pigment for advanced ink. Organic pigments are widely used in inks, paints, coatings, raw pulp coloring of synthetic fibers, pigment printing of fabrics, coloring of plastics, rubber and leather, among which the use of ink pigments is the largest. The output of organic pigments accounts for about a quarter of the total output of dyes.
Classification by structure
(1) Azo pigments account for 59%
(2) Phthalocyanine pigment accounts for 24%
(3) Triarylmethane pigment accounts for 8%
(4) Special pigments account for 6%
(5) Polycyclic pigments account for 3%