Life Sciences

The dyeing of leather is a chemically complex and commercially critical process of applying color to leather substrates by controlled adsorption, diffusion, and fixation. There are a number of types of dye commonly used in the leather industry: acid dyes, basic dyes, direct dyes, metal complex dyes, sulfur dyes, pre-metalized dyes, and reactive dyes. Each type of dye is used in specific types of leather for specific end-use requirements.
Acid dyes (anionic) are widely used in chromium-tanned leathers for their bright colors and deep penetration. In contrast, basic dyes (cationic) are more suitable for vegetable-tanned leather due to their affinity for the anionic sites in the leather matrix. However, they generally exhibit poor light and rubbing fastness.

Direct dyes color leather without mordants; however, they tend to remain on the surface rather than penetrating into the substrate and therefore often have poor lightfastness. Metal complex dyes (commonly chromium-based) are widely used in high-end leather and fur products for their excellent fastness and their soft, lustrous appearance. Sulfur dyes and pre-metalized dyes give deeper tones but have poor lightfastness. Reactive dyes provide covalent bonding with collagen fibers and have excellent wash and lightfastness but are not compatible with chromium-tanned leathers.

Created: 02 Aug 2025 08:08:23 AM
Last edited: 02 Aug 2025 08:08:23 AM