China Leather Auxiliaries Suppliers - Tanning, Finishing, and Coating Products from Leading Factory

This stage transforms raw hides into storable, tanned "naked hides," primarily removing impurities and restoring the hide to its natural state.

• Immersion Auxiliaries Contain surfactants and preservatives. They help dry, salted raw hides quickly and evenly absorb water to soften them, restoring them to a fresh hide state, while preventing bacterial growth that could lead to rotting.
• Degreasing Agents The main component is surfactant. For hides with high fat content (such as pigskin and sheepskin), it efficiently emulsifies and removes the oils within the hide, ensuring smooth penetration of subsequent chemical materials.
• Lime / Depilatory Agents Typically a combination of sulfides and lime. Responsible for removing hair and epidermis, and appropriately swelling and loosening the leather fibers to prepare for subsequent cutting and separating of collagen fibers.

This is the most crucial step, using tanning agents to transform perishable "hide" into stable and durable "leather."

• Mineral Tanning Agents The most commonly used is chrome tanning agent, which imparts excellent softness, resistance to damp heat, and fullness to leather.
• Synthetic / Vegetable Tanning Agents Such as phenolic synthetic tanning agents or vegetable tannins. They can be used alone (to produce heavy leather), but are more often used in combination with chrome tanning agents as retanning agents to adjust the fullness, grain density, and hand feel of the leather.
• New Environmentally Friendly Tanning Agents Chrome-free/formaldehyde-free tanning agents have become a research hotspot. For example, tanning agents developed using hyperbranched polymers not only effectively tan (making the leather shrinkage temperature >75℃) but also possess good biodegradability.

The tanned leather is still relatively dry. This stage mainly involves "moisturizing" and "shaping" the leather.

• Natural Oil Processings Such as sulfated castor oil (Taikoo oil), succulent fish oil, etc. Used to lubricate leather fibers, giving the leather a soft, full feel and a certain degree of water resistance and breathability.
• Synthetic Fatliquoring Agents More stable, such as phosphate esters and bound fatliquoring agents.
• Functional Fatliquoring Agents Such as silicone-modified fatliquoring agents, which can give leather a silky smooth feel and excellent resistance to yellowing.
• Retanning Agents / Fillers Used before and after fatliquoring, such as acrylic resin retanning agents, to fill the fiber gaps in soft areas of the leather, making the thickness and feel of the entire piece of leather more uniform, while also enhancing the leather's abrasion resistance and strength.

This stage involves "dressing up" and "coating" the dried leather surface to cover imperfections and give it the final color, shine, and feel.

• Film-forming Agents Such as water-based polyurethane and acrylic resin emulsions — the main components of the coating, forming a thin film that adheres to the leather surface.
• Coloring Agents Dyes or pigment pastes responsible for giving the leather the desired color.
• Hand Feel Agents Such as amino polyether modified silicone oil emulsions — adjust the smoothness, waxiness, or oiliness of the leather surface, improving tactile quality.
• Leveling Agents & Thickeners Help the coating spread evenly during drying, preventing brush marks or orange peel texture; thickeners adjust viscosity to suit spraying and roller coating methods.
• Defoamer Eliminates air bubbles generated during mixing and application of the coating slurry, preventing defects such as pinholes in the coating.
• Crosslinking Agent / Fixer Improves the coating's resistance to wet rubbing, dry rubbing, and solvents, resulting in stronger color and coating adhesion.