Direct Red 28 is a synthetic dye belonging to the class of direct dyes. It is also known by other names such as Direct Scarlet 4BS and C.I. 16255. Here are the properties of Direct Red 28:

1. Chemical Structure: Direct Red 28 has a complex chemical structure containing azo and azine chromophores. Its chemical formula is C20H12N4Na2O7S2.

2. Color and Appearance: Direct Red 28 is a water-soluble dye and usually appears as a red powder or fine crystals. It provides a vibrant red color.

3. Solubility: Direct Red 28 is highly soluble in water and forms clear to slightly colored solutions. It has limited solubility in organic solvents.

4. Stability: Direct Red 28 exhibits good lightfastness and is generally stable when exposed to light. However, its stability can vary depending on the specific formulation, concentration, and application. It may have limited resistance to fading and color change in certain conditions.

5. Application: Direct Red 28 is widely used as a dye in various industries, including textiles, paper, leather, and cosmetics. It is commonly employed for coloration of fabrics, yarns, fibers, and paper products. In cosmetics, it may be used in products like hair dyes and makeup.

6. Toxicity: Direct Red 28 is considered to have low acute toxicity. However, as with any chemical substance, it is important to handle it with proper precautions and adhere to safety guidelines provided by the manufacturer.

7. Regulation: The production, use, and handling of Direct Red 28 may be subject to specific regulations and guidelines established by regulatory authorities, such as the FDA (Food and Drug Administration) or REACH (Registration, Evaluation, Authorization and Restriction of Chemicals). These regulations aim to ensure the safe use and handling of the dye, particularly in applications that involve direct contact with the skin or ingestion.