There are many types of organic pigments, and there are many ways to classify them. The more commonly used taxonomies are:
1. Classification according to different chromatograms, so that the pigments are divided into: yellow, orange, red, purple, brown, blue, green pigments, etc .;
2. Classified according to the functionality of the pigment, so that the pigment is divided into: ordinary pigments, fluorescent pigments, pearlescent pigments, color-changing pigments, etc .;
3. According to the application object, the pigments are classified into: paints and coatings, inks, plastics and rubbers, cosmetics, etc.
4. According to the color body of the pigment molecule, the pigment can be roughly divided into two categories: azo pigments and non-azo pigments.
1. Azo pigments
In this type of pigment, it can be further classified according to the number of azo groups contained in the pigment molecule, or the structural characteristics of the diazo component and the coupling component.
1. Monoazo yellow and orange pigments
Monoazo yellow and orange pigments mean that the pigment molecule contains only one azo group and their chromatograms are yellow and orange. The coupling components that make up such pigments are mainly acetoacetanilide and its derivatives and pyrazolone Its derivatives.
The manufacturing process of monoazo yellow and orange pigments is relatively simple, many varieties, and most have good light fastness, but due to their small molecular weight and other reasons, their solvent resistance and migration resistance are not ideal. Monoazo yellow and orange pigments are mainly used for general quality air-drying paints, latex paints, printing inks and office supplies. Typical varieties are Hansa Yellow 10G (C.I. Pigment Yellow 3)
2. Disazo pigment
The disazo pigment refers to a pigment containing two azo groups in the pigment molecule. The production process of this kind of pigment is relatively complicated. The color spectrum is yellow, orange and red. Their light fastness is not ideal, but their solvent resistance and migration resistance are better. Mainly used in general quality printing inks and plastics, less used in coatings. Typical varieties are benzidine yellow (C.I. Pigment Yellow 12)
3. Naphthol series pigments
From the chemical structure point of view, naphthol series pigments also belong to monoazo pigments, but they use naphthol as the coupling component and the chromatography is mainly orange and red. In order to distinguish them from yellow and orange monoazo pigments, It is classified as -naphthol series pigment. Their light fastness, solvent resistance and migration resistance are all ideal, but they are not resistant to alkalis. The production process is as easy as the general meaning of monoazo pigments, and is mainly used for paints that require higher light fastness. And paint. Typical varieties are toluidine red (C.I. Pigment Red 3)
4. Naphthol AS series pigments
Naphthol AS series pigments refer to pigments with naphthol AS and its derivatives as coupling components in the pigment molecule. The production difficulty of this kind of pigment is slightly higher than that of general monoazo pigments, and the chromatography includes yellow, orange, red, purple sauce, magenta, brown and purple. Their light fastness, solvent resistance and migration resistance are generally used mainly for printing inks and paints. Typical varieties are Evergreen Red FR (C.I. Pigment Red 2)
5. Azo lake pigments
The precursor of this kind of pigment is a water-soluble dye, which contains sulfonic acid groups and carboxylic acid groups in the molecule, and forms a water-insoluble pigment through the action of a precipitant. The precipitants used are mainly inorganic acids, inorganic salts and carriers. The production of these pigments is as easy as that of ordinary monoazo pigments, and the chromatography is mainly yellow and red. Their light fastness, solvent resistance and migration resistance are generally used in printing inks. Typical varieties are golden red C (C.I. Pigment Red 53: 1).
6. Benzimidazolone pigment
The benzimidazolone pigment derives its name from the contained 5-amidobenzimidazolone group.
Benzimidazolone organic pigments are a class of high-performance organic pigments. Although they are azo pigments in terms of chemical classification, their application performance and various fastnesses cannot be compared with other azo pigments. The color of benzimidazolone pigments is very firm and suitable for most industrial sectors. Because of the price / performance ratio, they are mainly used in high-end occasions, such as: original car topcoat and repair paint, high-rise building exterior wall paint and high-end plastic products. The typical varieties are Yonggu Yellow S3G (C.I. Pigment Yellow 154).
7. Azo condensation pigment
The molecular structure of these pigments looks like ordinary disazo pigments, but they are formed by the condensation of two monoazo pigments containing carboxylic acid groups through a binary aromatic amine. The production process of such pigments is relatively complicated, and the chromatography is mainly yellow and red. Their light fastness, solvent resistance and migration resistance are very good. They are mainly used for the coloring of the stock solutions of plastics and synthetic fibers. Typical varieties are Gumei Deyellow 3G (C.I. Pigment Yellow 93).
8. Metal complex pigment
Such pigments are complexes of azo compounds and azepine compounds with transition metals, and the number of varieties that have been commercially produced is small. Before complexing with metal ions, the color of such azo compounds and azamethine compounds is relatively bright, but once complexed with metal ions, the color of the resulting metal complex pigment is much darker. The advantage of complexing is to give azo compounds and azamethine compounds high light fastness and weather fastness. The transition metals used in the existing pigments are mainly nickel, cobalt, copper and iron, and their chromatograms are mostly yellow, orange and green. They are mainly used for automotive paints and automotive paints that require high light fastness and weather fastness Other coatings. Typical varieties are C.I. Pigment Yellow 150.
2. Non-azo pigments
Non-azo pigments generally refer to polycyclic or fused ring pigments. Such pigments are generally high-grade pigments with high application fastness, mainly used in high-grade occasions. In addition to phthalocyanine pigments, their manufacturing process is quite complex and the production cost is high.
1. Phthalocyanine pigment
Phthalocyanine itself is a macrocyclic compound and does not contain metallic elements. Typical varieties are phthalocyanine blue B (C.I. Pigment Blue 15).
2. Quinacridone pigments
The chemical structure of quinacridone pigment is tetrahydroquinoline diacridone, but it is traditionally called quinacridone. Although the molecular weight of quinacridone pigments is much smaller than phthalocyanine pigments, they have high light fastness and weather fastness like the latter. Because their chromatograms are mainly red and purple, they are commercially available. It is often called phthalocyanine red.
3. Thioindigo pigments
This type of pigment has high light fastness, weather fastness and heat stability. Their production process is not very complicated. The color spectrum is mainly red and purple, which is often used in automotive paints and high-end plastic products. Because they are less toxic to the human body, they can also be used as food colors. Typical varieties are Cosmetic Pink RC01 (C.I. Pigment Red 181)
4. Anthraquinone pigment
Anthraquinone pigments refer to a class of pigments that contain anthraquinone structures in their molecules or use anthraquinone as a starting material. They are also a class of older compounds that were originally used as vat dyes. They have a very strong color and a wide chromatographic range, but the production process is so complicated that the production cost is very high. Due to the price / performance ratio, not all anthraquinone vat dyes can be used as organic pigments.
The typical varieties of anthrapyrimidine pigments are C.I. Pigment Yellow 108
Typical species of indanthrone pigment are C.I. Pigment Blue 60
The typical varieties of pyrene anthrone pigments are C.I. Pigment Orange 40
The typical varieties of dibenzopyrene dione pigments are C.I. Pigment Red 168
5. Dioxazine pigment
The precursor of this kind of pigment is triphenyldioxazine, which itself is orange and has no value as a pigment. Its 9,10-dichloro derivative can be used as a purple pigment after pigmentation. There are few existing dioxazine pigment varieties, and the most typical variety is Yonggu Violet RL (C.I. Pigment Violet 23). The pigment is resistant to almost all organic solvents, so it can be used in many application media and has good fastness. The basic hue of the pigment is red light purple, and the blue light color can also be obtained through special pigmentation treatment. Its coloring power is particularly high in almost all application media, and only a small amount can give a satisfactory color depth.
3. Aromatic methane pigments
The product of three hydrogens on methane replaced by three aromatic rings is called triarylmethane. To be precise, triarylmethane used as a pigment is actually a cationic compound, and at least two of the three aromatic rings carry amino groups (or substituted amino groups). This type of compound is also relatively old, there are two types, one is in the form of an internal salt, that is, the molecule contains a sulfonic acid group, which forms an internal salt with the parent cation; the other is a salt formed by the parent cation and a complex anion. They are characterized by very bright colors and very high tinting strength, but the fastness of each item is not very good. The color spectrum is blue and green, which are mainly used for printing inks. Typical varieties are Light Blue R (C.I. Pigment Blue 61) and C.I. Pigment Violet 3.
1,4-pyrrolopyrrole dione pigment
1,4-Pyrrolopyrrole dione pigment (ie DPP pigment) is the most influential new color body pigment in recent years. It is a new type of high-performance organic pigment developed by Ciba in 1983. , The production difficulty is higher. DPP pigments are cross-conjugated hair color systems, and the chromatograms are mainly bright orange and red. They have high light fastness, weather fastness and heat stability, but they are not resistant to alkalis. It is often used alone or mixed with other pigments to prepare automotive paints. The typical varieties are DPP red (C.I. Pigment Red 255).
Quinophthalone pigments
Quinophthalone itself is an older compound, but it has not been used as a pigment for a long time. This type of pigment has very good light fastness, weather fastness, heat resistance, solvent resistance and migration resistance. The shade is mainly yellow, and the color is very bright. It is mainly used to modulate the coloring of automotive paints and plastic products. The typical variety is CI Pigment Yellow 138.