Tanning is the process of getting ready or processing skins/ hides into leather using tannic acid. The raw collagen fibres of the pelt are transformed into a stable material that will not rot. The principal distinction between uncooked hides and tanned hides is that raw hides dry out to form a hard, inflexible material that when re-wetted (or wetted back) putrefies, while tanned materials dries out to a flexible kind that doesn’t develop into putrid when wetted back. The tanning process significantly improves the natural qualities of the leather comparable to its dimensional stability, abrasion resistance, chemical and warmth resistance, its resistance to repeated cycles of wetting and drying.
Significance of Tanning
1. It protects the leather from being dehydrated- The tanning processes always be certain that the leather maintains its inside moisture.
2. It protects the leather from decaying when subjected to water- Chemical remedy of leather which is a part of the tanning process prevents the leather from going bad because of rotting.
3. It makes the leather porous- Working on the leather through the tanning processes opens up the leather in order that it turns into airy and absorbent.
4. It vastly improves the tensile energy of the leather- Tanning builds up resilience in the leather. This makes the leather resist every kind of climate conditions.
5. It enhances the pliability 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 production of leather articles.
Sorts of Tanning Processes
1. Vegetable-tanning: This tanning process entails the usage of tannins and other ingredients found in vegetable matter derived from wood and plants. Examples embody chestnut, oak, redoul, tanoak, hemlock, quebracho, mangrove, wattle (acacia), and myrobalan. It’s supple and brown in colour, with the exact shade relying on the combination of chemical substances and the color of the skin. It’s the solely form of leather suitable for use in leather carving or stamping.
Vegetable-tanned leather is not stable in water; it tends to discolour, and if left to soak after which dried will cause it to shrink, render it less supple, and harder. In scorching water, it will shrink drastically and partly gelatinize, changing into rigid and finally brittle.
2. Chrome-tanning: This tanning process was invented in 1858. It’s the most generally used tanning process today. It entails using chromium sulfate and different salts ofchromium. It is more supple and pliable than vegetable-tanned leather and doesn’t discolour or lose shape as drastically in water as vegetable tanned leather-tanned. Additionally it is often called wet-blue for its color derived from the chromium. More esoteric colors are possible utilizing 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 have a tendency to provide a really supple, soft and pliable leather like chamois.
5. Combination tanning: This is a tanning technique that mixes or more of the above tanning methods discussed. Principally, it is a mixture of vegetable and chemical tanning. The pelts are first tanned using the chrome tanning method and is later re-tanned utilizing the vegetable tanning process. A blend of two tanning methods is deliberately carried out to achieve a very supple leather. Additionally, leather that’s to obtain a finishing technique because of its last use typically goes via the combination tanning process.