Vegetable Tanning Extract Powder is a concentrated natural tannin material derived from plant sources such as quebracho, chestnut, or mimosa. It serves as the primary tanning agent in vegetable tanning processes, converting raw hides into durable leather through polyphenol cross-linking with collagen fibers. This material produces firm, breathable leather with distinctive natural characteristics, commonly used for saddlery, footwear soles, and artisanal goods. The powder form allows for precise formulation control and efficient storage and transportation in industrial settings. Key parameters include tannin content (55–65% by weight, ISO 14088), moisture content (5–8%, ISO 4684), pH (3.5–4.5 in 10% solution, ISO 4045), particle size (100–200 mesh, ISO 2591-1), bulk density (0.5–0.7 g/cm³, ISO 697), solubility temperature (60–80°C), tannin content on dry basis (60–70%, ISO 14088), insoluble ash (≤2%, ISO 4047), sulfated ash (≤5%, ISO 4047), heavy metals as Pb (≤10 mg/kg, ISO 17072-1), storage temperature (5–30°C), shelf life (24 months), and packaging (25 kg multi-layer kraft paper bags with PE liner). These values are reference ranges for directory purposes and must be verified with the supplier for specific batches. The material is intended for use in industrial leather processing; users should confirm that the product meets their specific application requirements and applicable standards.
Tannins penetrate the hide collagen matrix and form hydrogen bonds and hydrophobic interactions, stabilizing the protein structure against decay. The polyphenolic compounds in the extract bind to collagen fibers, cross-linking them and increasing hydrothermal stability. This process transforms raw hides into leather that is resistant to microbial attack and heat. The effectiveness depends on tannin concentration, pH, temperature, and penetration time. Proper dissolution and pH adjustment are critical for optimal uptake. The powder must be fully dissolved in water at the recommended temperature range to ensure uniform tannin distribution. Insufficient penetration or incorrect pH can lead to incomplete tanning, resulting in leather that is prone to putrefaction or lacks firmness. Over-tanning may cause excessive shrinkage or stiffness. The process is typically carried out in drums or pits, with gradual addition of the extract to avoid surface precipitation.
