Organic pigments are insoluble organic compounds that are usually added to the substrate in a highly dispersed state to color the substrate. It is fundamentally different from dyes in that dyes are soluble in the dyeing medium used, whereas pigments are neither soluble in the medium in which they are used nor in the substrate in which they are colored. Many pigments and dyes are consistent in chemical structure, using different methods, can make them convert to each other, such as some VAT dyes and sulfide VAT dyes, if its reduction into cryptochrome, can be used as fiber dyes; If not reduced, can be used as pigment for advanced ink. Organic pigments are widely used in ink, paint, coatings, synthetic fiber pulp coloring, as well as fabric paint printing, plastic and rubber, leather coloring, among which ink pigment use the largest. The production of organic pigments accounts for about a quarter of the total production of dyes.
Physical property
Organic pigments have bright colors and strong coloring power. No toxicity, but some varieties of light resistance, heat resistance, solvent resistance and migration resistance is often inferior to inorganic pigments.
The variety of colors is endless and colorful, but there is a certain internal relationship between the various colors, each color can be determined by three parameters, namely hue, brightness and saturation. Hue is the characteristic that color differs from each other, which is determined by the chromatographic composition of the light source and the perception of the human eye produced by the wavelength emitted by the surface of the object. It can distinguish the characteristics of red, yellow, green, blue, purple and so on. Brightness, also known as brightness, is the characteristic value that represents the change of brightness degree of the object surface; By comparing the lightness of various colors, colors are divided into bright and dark. Saturation, also known as chrominance, is the characteristic value indicating the intensity of an object’s surface color, which distinguishes between bright and dark colors. Hue, lightness, and saturation form a solid, and using these three to build a scale, we can measure color numerically. There are many colors in nature, but the most basic are red, yellow and blue, which are called primary colors.
Classification by structure
(1) Azo pigment accounted for 59%
(2) Phthalocyanine pigment accounted for 24%
(3) Triaromatic methane pigment accounted for 8%
(4) Special pigments accounted for 6%
(5) Polycyclic pigment accounted for 3%