Лако-красочные материалы — производство

Monoazo pigments are obtained by coupling a diazonium salt of a substituted aromatic amine with a suitable coupling agent. Acetoa — cetic arylides are used as coupling agents to yield a range of yellow pigments generically known as arylamide yellow, while b-naphthol is used for orange and red pigments generically known as b-naph- thol red. Another important group of pigments, an extension of the b-naphthol red pigments, use arylides of 2-hydroxy-3-naphthoic acid as coupling agents and are known as naphthol AS pigments. Most monoazo pigments have poor heat stability along with poor sol­vent and migration resistance that limit their applications. They are used extensively in alkyd-based architectural coatings, in emulsion paints and in printing inks. Typical examples are Pigment Yellow 1, 3, 73, 74 and 98, Pigment Orange 5, Pigment Red 3, 4 and 6 and Pig­ment Red 2, 12, 23 and 112. Some examples are shown in Figure 3.9.