TAN 420C is primarily utilized in the textile industry as a dyeing assistant. It enhances the dye uptake on fabrics, ensuring vibrant and uniform coloration. This chemical is particularly effective in improving the fastness properties of dyes, making the colors more resistant to washing, light, and friction. Additionally, TAN 420C is used in the treatment of synthetic fibers, where it helps in achieving better dye penetration and consistency. Its application also extends to the leather industry, where it aids in the dyeing process to produce high-quality, evenly colored leather products. Overall, TAN 420C plays a crucial role in ensuring efficient and effective dyeing processes across various materials.