What is the color index of Acid Yellow 73?

Acid Yellow 73, also known as Food Yellow 4 in some regions, is a synthetic organic compound commonly used as an acid dye. As a reliable supplier of Acid Yellow 73, I am often asked about its color index. In this blog post, I will delve into the concept of color index, specifically focusing on Acid Yellow 73, and also touch upon its properties, applications, and comparison with other acid dyes.

Understanding the Color Index

The Color Index (CI) is a standardized system jointly maintained by the Society of Dyers and Colourists (SDC) in the United Kingdom and the American Association of Textile Chemists and Colorists (AATCC). It is a comprehensive database that assigns unique numbers to dyes, pigments, and fluorescent brightening agents. These numbers serve as a universal reference for identifying and classifying colorants based on their chemical structure and application method.

The Color Index number of a dye consists of two parts: a generic name and a numerical identifier. For example, Acid Yellow 73 is the generic name, and the number 73 indicates its specific position within the acid yellow dye category. The generic name provides information about the dye's application class (in this case, acid dyes) and color (yellow). Acid dyes are typically used for dyeing protein fibers such as wool, silk, and nylon, as well as some synthetic fibers.

Color Index of Acid Yellow 73

The Color Index number for Acid Yellow 73 is CI 45350. This number is crucial for several reasons. Firstly, it allows manufacturers, researchers, and users to accurately identify and specify the dye they are working with. When ordering Acid Yellow 73, suppliers and customers can refer to the CI number to ensure they are getting the correct product. Secondly, the CI number provides valuable information about the dye's chemical structure and properties. By referring to the Color Index database, one can access data on the dye's solubility, fastness properties, and spectral characteristics.

Acid Yellow 73 is a monoazo dye with a bright yellow color. Its chemical structure consists of a diazo component and a coupling component, which are linked by an azo group (-N=N-). The presence of sulfonic acid groups (-SO₃H) in the molecule makes it water-soluble and suitable for use in aqueous dyeing systems.

Properties of Acid Yellow 73

• Color and Shade: Acid Yellow 73 imparts a vivid yellow color to the substrate. The shade can vary slightly depending on the dyeing conditions, such as pH, temperature, and the type of fiber being dyed. It is known for its good tinctorial strength, which means that a relatively small amount of dye can produce a deep and intense color.
• Solubility: As mentioned earlier, Acid Yellow 73 is highly soluble in water due to the presence of sulfonic acid groups. This solubility makes it easy to prepare dye solutions and ensures uniform dyeing of the substrate.
• Fastness Properties: Fastness refers to the ability of a dye to resist fading or bleeding under various conditions. Acid Yellow 73 generally exhibits good fastness to light, washing, and perspiration. However, its fastness properties can be influenced by factors such as the type of fiber, dyeing method, and after-treatment.

Applications of Acid Yellow 73

• Textile Industry: Acid Yellow 73 is widely used in the textile industry for dyeing wool, silk, and nylon fibers. It can be applied using various dyeing methods, including exhaust dyeing, continuous dyeing, and printing. The dye produces bright and attractive colors on these fibers, making them suitable for a wide range of textile products, such as clothing, upholstery, and carpets.
• Food Industry: In some countries, Acid Yellow 73 is approved for use as a food coloring agent. It is used to impart a yellow color to food products such as beverages, confectionery, and dairy products. However, the use of food dyes is strictly regulated to ensure consumer safety.
• Other Applications: Acid Yellow 73 can also be used in other industries, such as the paper, leather, and cosmetic industries. In the paper industry, it is used for dyeing paper pulp and surface coating. In the leather industry, it is used for dyeing leather goods. In the cosmetic industry, it is used in the formulation of makeup products, such as lipsticks and eyeshadows.

Comparison with Other Acid Dyes

To better understand Acid Yellow 73, it is useful to compare it with other acid dyes. Here are some examples of other acid dyes and their characteristics:

• Acid Blue 9: Also known as Brilliant Blue FCF, Acid Blue 9 is a synthetic organic compound with a bright blue color. It is commonly used in the food, pharmaceutical, and cosmetic industries. Compared to Acid Yellow 73, Acid Blue 9 has a different chemical structure and color, which makes it suitable for different applications.
• Acid Red 92: Acid Red 92 is a synthetic red dye that is widely used in the textile and food industries. It has good fastness properties and can produce a deep and intense red color. In contrast, Acid Yellow 73 produces a yellow color, and its fastness properties may vary depending on the application.
• Acid Blue 7: Acid Blue 7 is another acid dye with a blue color. It is used for dyeing wool, silk, and nylon fibers. Like Acid Yellow 73, it is water-soluble and has good tinctorial strength. However, its chemical structure and spectral characteristics are different from those of Acid Yellow 73.

Quality Assurance and Supply

As a supplier of Acid Yellow 73, we are committed to providing high-quality products that meet the strictest industry standards. Our Acid Yellow 73 is manufactured using advanced production processes and undergoes rigorous quality control tests to ensure its purity, color strength, and fastness properties. We also offer customized solutions to meet the specific needs of our customers.

If you are interested in purchasing Acid Yellow 73 or have any questions about our products, please feel free to contact us. Our experienced sales team will be happy to assist you with your inquiries and provide you with detailed product information and pricing. We look forward to establishing long-term business relationships with you and helping you achieve your coloring goals.

References

• Society of Dyers and Colourists. (n.d.). The Color Index. Retrieved from [SDC Website]
• American Association of Textile Chemists and Colorists. (n.d.). Color Index. Retrieved from [AATCC Website]
• Colour Index International. (n.d.). Acid Yellow 73. Retrieved from [CI International Database]