CAUSTIC SODA APPLICATION IN LEATHER INDUSTRY

Hossein Moshiri

Caustic soda, or sodium hydroxide (NaOH), is a highly versatile and extensively utilized chemical compound, with a notable role in the leather sector. The leather industry relies heavily on caustic soda for various purposes, including the preparation of hides and skins, as well as leather finishing.

First step

In the first place, caustic soda finds its application in the initial phase of leather preparation, commonly referred to as beamhouse operations. In this particular procedure, the hides and skins undergo treatment with a caustic soda solution in order to eliminate hair, dirt, and grease. Caustic soda acts as a powerful alkaline agent, dissolving these impurities and facilitating their removal. This is a crucial step as it ensures the cleanliness and quality of the leather.

Deliming

Moreover, caustic soda plays a crucial role in the deliming and bating process. Deliming involves the removal of lime (calcium hydroxide) from the hides and skins after they have undergone the initial beamhouse treatment. Caustic soda is used to neutralize the lime, forming a soluble salt that can be easily washed away. This step is essential as excess lime can hinder the subsequent processing of leather.

Removal of non=fibrous components

Furthermore, bating is an important process that involves the removal of the remaining non-fibrous components from the hides and skins. Caustic soda is used to create an alkaline environment, which aids in the loosening and removal of these substances. This process enhances the softness, flexibility, and uniformity of the leather, making it more suitable for further treatment.

Leather finishing

In addition to the preparation of hides and skins, caustic soda finds application in leather finishing. Leather finishing involves multiple processes, including the removal of natural oils and fats, dyeing, and the application of various finishes and coatings. Caustic soda is used in the degreasing process, where it effectively removes the residual oils and fats from the tanned leather. This step is crucial for achieving a consistent and even dye penetration.

pH adjusting

Moreover, caustic soda is used as a pH adjuster in various dyeing processes. It helps in maintaining the optimal pH levels required for dye fixation and color development. Furthermore, caustic soda can also be used to treat and neutralize certain chemicals used in leather finishing, ensuring safe and consistent results.

In conclusion, caustic soda is a vital chemical compound in the leather industry. Its applications range from the initial preparation of hides and skins to the finishing processes. Caustic soda’s alkaline properties make it an effective and versatile agent for the removal of impurities, deliming, bating, degreasing, and pH adjustment. It contributes significantly to the production of high-quality leather, ensuring desirable characteristics such as cleanliness, softness, and uniformity. Without caustic soda, the leather industry would face numerous challenges in achieving the desired outcomes in terms of product quality and performance.