Classification of organic pigments
How to classify organic pigments? Pigments made from colored organic compounds are referred to as organic pigments. Refers to a class of pigments made from organic compounds that have color and other properties of a range of pigments. Pigment properties include lightfastness, water immersion resistance, acid resistance, alkali resistance, organic solvent resistance, heat resistance, crystal stability, dispersibility and hiding power. The difference between an organic pigment and a dye is that it has no affinity with the object to be colored, and only the organic pigment adheres to the surface of the object by an adhesive or a film-forming substance, or is mixed inside the object to color the object. The intermediates, production equipment and synthesis processes required for their production are similar to the production of dyes, so organic pigments are often produced in the dye industry. Compared with general inorganic pigments, organic pigments generally have high tinting strength. The particles are easy to be ground and dispersed, are not easy to precipitate, and have bright colors, but are poor in light fastness, heat resistance and weather resistance. Organic pigments are commonly used for coloring materials such as inks, coatings, rubber products, plastic products, stationery, and building materials.
Classified by structure: (1) azo pigments accounted for 59% (2) phthalocyanine pigments accounted for 24% (3) triarylmethane pigments accounted for 8% (4) special pigments accounted for 6% (5) polycyclic pigments accounted for 3%
The organic pigments have bright colors and strong tinting strength; the density is small and non-toxic, but some varieties are often inferior to inorganic pigments in light resistance, heat resistance, solvent resistance and migration resistance. The variety of colors varies endlessly and colorfully, but there is a certain intrinsic connection between the colors. Each color can be determined by three parameters, namely hue, lightness and saturation.
Hue is a feature in which colors are distinguished from each other, and is determined by the chromatographic composition of the light source and the sensation of the wavelength emitted by the surface of the object to the human eye, and distinguishes characteristics such as red, yellow, green, blue, and purple. Brightness, also known as brightness, is a characteristic value that indicates the degree of change in the surface of an object. By comparing the brightness of various colors, the color has a distinction between this and darkness.