Pigment Red 49:1 CAS #1103-38-4

Some of its physical and chemical properties are as follows:
Color: neutral red Molecular weight: 822.16 Molecular formula: C_{40} H_{26} N_{4} O_{8} S_{2}・Ba Oil absorption (ml/100g): 40-65pH: 7.7-8.7
In terms of fastness performance, it has the following characteristics:
Light resistance: 4 Heat resistance: 180°C Water resistance: 4 Oil resistance: 3 Acid resistance: 4 Alkali resistance: 2
This pigment is suitable for ink coloring, especially for publishing gravure ink; the dosage form is suitable for water-based ink. It is a red powder with a yellow luster, insoluble in water and ethanol, and is commonly used in inks, iron printing, leather, rubber, plastics and watercolor pigments.
Its preparation method is usually based on 2-naphthylamine-1-sulfonic acid as the raw material, after diazotization, it is coupled with 2-naphthol in an alkaline solution, and barium chloride (or calcium) is added to obtain it. The specific steps include the preparation of diazo liquid, the preparation of coupling liquid, coupling reaction, lake reaction and post-treatment. In some preparation methods, a specific second diazo component, a second coupling component, a nonionic surfactant, a pigment modifier, etc. are added to improve the performance of the pigment, such as reducing viscosity, improving tinting strength and glossiness, etc.