How is Leather Made?

How is Leather Made?

Brief Background of Leather Production

Leather is a versatile and durable material used for centuries in various industries. From fashion to interiors, leather is prized for its unique properties and elegance. But have you ever wondered how leather is made? Leather is made through tanning, which involves treating animal hides or skins to preserve and transform them into a durable material. 

Leather production is a long technical process that must be followed precisely and carefully to produce high-quality leather with the same finish consistently. The process will start with the animal hide or skin, ending the journey to a piece of leather ready to be made into bags, clothing, or any other leather product. 

Leading Countries in Leather Production

Suppose you are wondering what countries are leading in leather production. Geographically, Asia Pacific is currently the largest market for leather and products with leather materials. Recently, this region has generated the highest revenue globally for leather goods. 

Brazil is the second largest leather producer in the world. Brazil’s leather industry produces more than 2.4 billion square feet each year. Leather production in Brazil mainly consists of lightweight leather produced from cattle. Leather produced from cattle in Brazil accounts for approximately 1.8 billion square feet per year, making it the largest contributor to Brazil’s leather industry.

Another is Italy, home to 300 upholstery and fashion leather tanneries. Northern Italian tanneries at Arzignano produce interior leather, while Santa Croce is famous for its fashionable leather. Europe’s mild climate and strict beef industry standards ensure ideal conditions for raw leather. Leather is a byproduct of the meat and hide industries that would otherwise go to waste and is transformed into a valuable and sustainable product.

Increased spending on personal goods due to growing fashion consciousness is one of the main reasons for the growth of this market. Rising customer purchasing power, changing lifestyles, and increasing smartphone penetration contribute to market growth. Let’s explore the fascinating process of making leather.

1. Preparation of Raw Materials

Leather can be made from the skin of almost any animal, including pigs, sheep, goats, and crocodiles. However, the most commonly used type of leather is a cow. Considered a byproduct of the meat and dairy industries, leathermaking uses hides that would otherwise be destroyed. Instead, making leather transforms the animal’s skin into a beautiful, valuable material that lasts decades.

Preparing the animals’ hides and skin involves five steps.

  1. Soaking: The hides or skins are washed and placed in water to remove dirt, blood, and other impurities. This process also makes the coats softer for the next stage.
  2. Liming: The hides or skins are soaked with lime or other alkaline substances to remove the hair, flesh, and fat. This process can take several days, stirring the hides in large vats of lime and water.
  3. Deliming: When the liming process is complete, the hides are washed to remove excess lime and other chemicals.
  4. Bating: The hides are treated with enzymes to soften further and prepare them for tanning.
  5. Pickling: The hides are treated with salt and acid to help preserve and prepare them for tanning.

2. Tanning

Tanning is the core process that transforms the hides into leather. It is a critical stage in leather manufacturing and requires specialized knowledge and equipment to produce high-quality leather products. Primary tanning changes pre-tanned hides into leather by preserving and preventing the decomposition of the leather. The hides are put into a tanning barrel with a chromium salt solution or vegetable tanning agent and roasted for 8 hours. 

Salt and tanning agents preserve the leather and soften it. This highly sophisticated device continuously heats the tanning solution, thus providing the best possible penetration into the skin. The fatty alcohol is then supplemented with natural cow’s oil to give the leather durability and softness. 

Several tanning methods include vegetable, chromium, combination, and synthetic tanning. 

Vegetable tanning uses natural plant extracts and produces stiff, sturdy leather, often used in belts and saddles. The most commonly used vegetable materials are chestnut, mimosa, and bark. 

Chromium tanning uses chromium salts and is faster, resulting in softer and more pliable leather, often used for garments and upholstery.

Combination tanning combines chromium and vegetable tanning, resulting in a full-bodied, soft, and supple leather.

Synthetic tanning involves synthetic chemicals and is less common than the other methods.

The tanning process involves several stages, including:

  1. Pre-tanning:This is the pre-treating stage for the hides with a solution of salt and acid to prepare them for the tanning process.
  2. Tanning:The hides are soaked with the tanning agent, penetrating the fibers and making the leather durable and resistant to decay.
  3. Neutralizing:The hides are washed to remove any excess tanning agent and restore the pH balance.
  4. Finishing:The tanned leather is then finished with various processes, including dyeing, buffing, and coating with waxes or oils, to enhance its appearance, texture, and durability.

3. Re-Tanning

After tanning, the hides are treated to neutralize any remaining chemicals. Re-tanning is then done to change the leather’s physical properties depending on its end use. The leather is re-tanned with chromium salts, vegetable materials, or a combination of both, giving it a unique feel or texture. The leather is again placed in the washing machine to remove excess moisture. The interfaces are sorted and stored again.

4. Dyeing

Leather can be dyed to achieve beautiful colors. Fat liquoring involves adding oils and emollients to make the leather soft, supple, and moisture-resistant. This can range from browns and blacks with leather to bright and bold colors. Each color is meticulously created using an exact computer program, with which it is possible to achieve consistent color every time.

These are the steps involved in the dyeing process:

  1. Preparation: The leather is cleaned, and any finishing agents or coatings are removed to prepare it for dyeing.
  2. Coloring: The dye is applied to the leather using various methods, such as spraying, immersion dyeing, or hand painting. The type of dye used can vary, such as acid dyes, direct dyes, or reactive dyes.
  3. Penetration: The leather is allowed to absorb the dye, and the dye penetrates the fibers to create a permanent color.
  4. Fixation: The leather is treated with a fixative, heat, to set the dye and ensure it does not bleed or fade.
  5. Finishing: The dyed leather is finished with various processes, including buffing, polishing, and coating with waxes or oils, to enhance its appearance, texture, and durability.

5. Finishing

Once the dyeing process is complete, the final step in leather production is finishing. This involves applying various treatments and finishes to the leather to enhance its appearance and performance. These treatments can include dyeing, embossing, and buffing. The finishing protects the surface and can be easier to clean. 

The finishing stage is critical to creating high-quality leather products that meet the desired appearance, texture, and durability standards. The techniques used for finishing vary depending on the type of leather and the intended use of the finished product. Here are some of the techniques experts use in this stage:

  1. Buffing: The surface of the leather is sanded to create an even and smother texture. This also helps to remove any imperfections or blemishes.
  2. Embossing: The leather is stamped with a pattern or design to create a textured surface. This is done using a heat press or rollers with engraved designs.
  3. Coating: A protective coating, such as wax or oil, is applied to the leather to increase its resistance to water, stains, and scratches. This can also enhance the leather’s appearance and give it a glossy or matte finish.
  4. Dyeing: As mentioned earlier, dyeing can also be done at the finishing stage to enhance the leather’s color and appearance.
  5. Polishing: The leather is polished to create a shiny surface and to remove any marks or scratches.
  6. Edge finishing: The edges of the leather, such as those on belts or bags, are finished with various techniques, such as burnishing, painting, or beveling, to give them a smooth and even appearance.

6. Final Inspection

Leather undergoes rigorous quality checks to meet the desired texture, color, and durability standards. Different tests are performed to ensure high-quality control. These tests include stain, abrasion, fading, and dimensional stability. Once the leather has been inspected, it is tested to ensure it exceeds all expected quality specifications.

Conclusion

Leather can be used for various products, including clothing, shoes, bags, furniture, and automotive upholstery. Its process involves complex and intricate stages crucial in creating high-quality leather. So, if you are holding a leather bag or wearing a leather jacket now, take a moment to scrutinize and appreciate the craftsmanship and precise skill of making this timeless material.