Tanning is the process of making ready or processing skins/ hides into leather utilizing tannic acid. The uncooked collagen fibres of the pelt are transformed right into a stable material that will not rot. The principal difference between uncooked hides and tanned hides is that raw hides dry out to type a hard, inflexible material that when re-wetted (or wetted back) putrefies, while tanned material dries out to a flexible kind that doesn’t develop into putrid when wetted back. The tanning process significantly improves the pure qualities of the leather equivalent to its dimensional stability, abrasion resistance, chemical and warmth resistance, its resistance to repeated cycles of wetting and drying.
Importance of Tanning
1. It protects the leather from being dehydrated- The tanning processes always make sure that the leather maintains its internal moisture.
2. It protects the leather from decaying when subjected to water- Chemical treatment of leather which is part of the tanning process prevents the leather from going bad on account of rotting.
3. It makes the leather porous- Working on the leather via the tanning processes opens up the leather hides in order that it turns into airy and absorbent.
4. It significantly improves the tensile strength of the leather- Tanning builds up resilience within the leather. This makes the leather resist all types of weather conditions.
5. It enhances the flexibleness of the leather- Tanning makes the leather supple and soft improving 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 use of tannins and different ingredients found in vegetable matter derived from wood and plants. Examples embody chestnut, oak, redoul, tanoak, hemlock, quebracho, mangrove, wattle (acacia), and myrobalan. It is supple and brown in color, with the precise shade depending on the combination of chemical substances and the colour of the skin. It is 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 and then dried will cause it to shrink, render it less supple, and harder. In hot water, it would shrink drastically and partly gelatinize, changing into inflexible and eventually brittle.
2. Chrome-tanning: This tanning process was invented in 1858. It is the most generally used tanning process today. It involves the use of chromium sulfate and other salts ofchromium. It is more supple and pliable than vegetable-tanned leather and does not discolour or lose shape as drastically in water as vegetable-tanned. It’s also often called wet-blue for its color derived from the chromium. More esoteric colours are potential using chrome tanning.
3. Mineral Tanning: In mineral tanning, the pelts are soaked in mineral substances usually the salts of chromium, aluminum and zinconium.
4. Oil Tanning: In this tanning process, the pelts are soaked in certain fish oils which tend to supply a very supple, soft and pliable leather like chamois.
5. Combination tanning: This is a tanning technique that combines two or more of the above tanning strategies discussed. Principally, it is a combination of vegetable and chemical tanning. The pelts are first tanned using the chrome tanning method and is later re-tanned using the vegetable tanning process. A blend of two tanning techniques is deliberately done to achieve a really supple leather. Also, leather that’s to obtain a finishing method because of its ultimate use typically goes by means of the combination tanning process.