What are the Processes Involved in Manufacturing Leather Products?

The leather industry in India is the oldest manufacturing industry. This industry focuses on employment generation and provides jobs to approximately 4.4 million people. With consistent high export earnings, this industry is one of India’s top 10 forex earners.

India is among the best locations for the leather industry because raw materials are available here in abundance. Around 11% of the world’s goat and sheep population and 20% of the world’s buffalo and cattle population exist in India, which serve as an essential raw material in this industry.

Process of Making Leather

Processing leather requires high accuracy to make products of the best finish. The process begins with animal hide and ends with leather pieces to make various products like bags, belts, furniture, shoes, wallets and other clothing. The whole unit comprises various processes which are as follows:

• Raw material: This is the first step, and it starts by extracting hide from animals like pigs, sheep, goats, and crocodiles. The hide is a common byproduct of the dairy industry. In this step, the skin and flesh are removed from the animal at the earliest because the material dries very quickly.
• Preservation: Preserving the material is crucial as it dries out very quickly. To preserve the material, a dehydrating process includes dry salting, air-drying, and pickling the material with salts and acids.
• Soaking: In this process, the hide is soaked in water for multiple hours to days to remove the salts and dirt from it and regain softness.
• Liming: The animal hide comprises some hairs that need to be removed. In this process, the hide is soaked in water and lime for one to two days to make it softer. 
• Fleshing: In this step, the hide is passed through a machine where extra flesh is removed, and several layers of the hide are created as different layers manufacture different products. The highest quality leather products are made from the upper part of the hide, and the lower part is used to make cheap leather. 
• Deliming: This process ensures that alkali is neutralised in the pelt, which avoids any changes in the PH because a difference in the PH level could distort the tissues.
• Bating: It is the process under which various enzymes are used to remove the lime and residual components. This process ensures that the pelt is ready for further processes.
• Pickling: For the tanning process, the pelt is required in a weakly acidic state. Hence, pickling is performed. In contrast, strong pickling solutions are useful when necessary to preserve and transport the pelt.
• Degreasing: Some water-based systems can be used to remove excess greases such as oils and natural fats from the hide.
• Tanning: The tanning process involves converting the proteins of the animal hide into a stable material by stopping decomposition and protecting the hide. Through this process, the inflexible hide is transformed into a flexible one. Depending upon the end-use of the leather, different tanning processes and materials are used. Below are some methods used in tanning in leather products manufacturing:

1.Chrome tanning: It is the most widely used tanning process, which involves soaking the animal skin or hide in tubs containing acidic salts and chromium tanning agents. Once the skin absorbs the chromium salts, the acidity is reduced. After the hide is tanned with chromium salts, the wet hide gets a pale blue colour. This is why they are also called ‘wet blue hides’. 

2.Vegetable tanning: This type of tanning has been used since ancient times. It takes longer to tan hide with this process than chrome tanning. It involves the use of tannins present in the barks and leaves of the trees. After the preparation phase, the animal skin is put into the tanning pit, where they are soaked in drums containing tanning solutions of varying strengths. For two to three months, the tanners move the animal hide from one drum to another to help the tanning agents get into the skin, imparting a distinct appearance to the hide. 

• Dyeing:   The dyeing process provides several leather colours that meet the current fashion requirements. Numerous dyeing methods are used, such as spraying, brush dyeing, drum dyeing and staining. Grease and blended oils are also used to give strength and softness to the leather.
• Finishing:  The last stage of leather making is finishing. At this stage, it is ensured that the leather is flexible and supple and has a glossy finish. A spray is applied to the leather to give a final touch. Several types of spray provide different finishing.

Conclusion

The leather industry in India is the oldest manufacturing industry and employs around 4.4 million people. The leather-making process requires high accuracy to make products of the best finish. Several steps need to be followed to make leather, including raw materials, preservation, soaking, liming, fleshing, tanning, and a lot more. Tanning is of several types: chrome tanning, vegetable tanning, and synthetic tanning.

The last process is finishing which ensures the glossy finish and flexibility of the leather, and a  spray is also applied to it to give the final touch.