Tanning is the process of preparing or processing skins/ hides into leather utilizing tannic acid. The uncooked collagen fibres of the pelt are reworked into a stable materials that won’t rot. The principal distinction between uncooked hides and tanned hides is that raw hides dry out to form a hard, rigid material that when re-wetted (or wetted back) putrefies, while tanned materials dries out to a flexible kind that does not turn into putrid when wetted back. The tanning process significantly improves the natural qualities of the leather akin to its dimensional stability, abrasion resistance, chemical and heat resistance, its resistance to repeated cycles of wetting and drying.
Significance of Tanning
1. It protects the leather from being dehydrated- The tanning processes at all times be sure that the leather maintains its inside moisture.
2. It protects the leather from decaying when subjected to water- Chemical therapy of leather which is part of the tanning process prevents the leather from going bad because of rotting.
3. It makes the leather porous- Working on the leather via the tanning processes opens up the leather in order that it turns into ethereal and absorbent.
4. It significantly improves the tensile energy of the leather- Tanning builds up resilience within the leather. This makes the leather resist all kinds of climate conditions.
5. It enhances the flexibility of the leather- Tanning makes the leather supple and soft bettering its workability and moulding qualities. This makes it straightforward to be utilized within the manufacturing of leather articles.
Kinds of Tanning Processes
1. Vegetable-tanning: This tanning process involves the usage of tannins and other ingredients found in vegetable matter derived from wood and plants. Examples embrace chestnut, oak, redoul, tanoak, hemlock, quebracho, mangrove, wattle (acacia), and myrobalan. It’s supple and brown in colour, with the exact shade depending on the combination of chemicals and the color of the skin. It is the solely form of leather suitable to be used in leather carving or stamping.
Vegetable-tanned leather is not stable in water; it tends to discolour, and if left to soak and then dried will cause it to shrink, render it less supple, and harder. In scorching water, it’ll shrink drastically and partly gelatinize, changing into rigid and ultimately brittle.
2. Chrome-tanning: This tanning process was invented in 1858. It’s the most generally used tanning process today. It entails the usage of chromium sulfate and different salts ofchromium. It’s more supple and pliable than vegetable-tanned leather and does not discolour or lose form as drastically in water as vegetable-tanned. It is also referred to as wet-blue for its color derived from the chromium. More esoteric colors are doable using chrome tanning.
3. Mineral Tanning: In mineral tanning, the pelts are soaked in mineral substances normally the salts of chromium, aluminum and zinconium.
4. Oil Tanning: In this tanning process, the pelts are soaked in sure fish oils which tend to supply a very supple, soft and pliable leather like chamois.
5. Mixture tanning: This is a tanning method that mixes two or more of the above tanning methods discussed. Largely, it’s a mixture of vegetable tanned leather and chemical tanning. The pelts are first tanned using the chrome tanning technique and is later re-tanned utilizing the vegetable tanning process. A blend of tanning techniques is deliberately carried out to achieve a very supple leather. Also, leather that is to receive a finishing approach because of its last use sometimes goes by the combination tanning process.