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Sardar Chemical Industries Limited is the manufacturer for acid dyes in Pakistan Since 1989. Acid dyes are a class of synthetic dyes widely used in the leather industry for coloring various types of leather, especially chrome-tanned hides. These dyes are water-soluble and typically contain sulfonic acid groups, which allow them to bind effectively to the positively charged amino groups present in leather proteins. In leather processing, acid dyes are preferred due to their brilliant shades, high color fastness, and ease of application. They penetrate well into the leather fibers, resulting in uniform coloration. The dyeing process usually takes place after tanning and neutralization, where the leather pH is adjusted to enhance dye uptake. The use of acid dyes also allows for a wide range of vibrant and subtle color tones, which are essential for fashion and upholstery leathers. However, careful control of dyeing parameters such as pH, temperature, and dye concentration is essential to achieve consistent results and avoid issues like poor fixation or uneven coloring. Additionally, environmental concerns regarding dye effluents have led to stricter regulations, prompting the leather industry to adopt cleaner dyeing technologies and more eco-friendly formulations.
Wide Color Range: From subtle pastels to vivid tones.
Good Fastness: Especially with metal complex types.
Economical: Efficient dye uptake with minimal waste.
Shifting toward eco-friendly acid dyes with lower toxicity.
Green Chemistry: Leather dyes remains effective and responsible.
Consistent Results: When process parameters are well-controlled.
Pre-treatment: After tanning and neutralization, the leather is adjusted to the required pH level, usually between 4.0 and 5.5.
Dye Application: Acid dyes are applied in aqueous solution, often with auxiliaries that aid in penetration and leveling.
Fixation: The dye is fixed onto the leather fibers through electrostatic interaction and sometimes enhanced with fixatives.
Drying and Finishing: Once dyed, the leather is dried and treated further to meet the final specifications (gloss, softness, waterproofing, etc.).
