Tanning is the process of making ready or processing skins/ hides into leather utilizing tannic acid. The raw collagen fibres of the pelt are transformed right into a stable materials that will not rot. The principal difference between raw hides and tanned hides is that uncooked hides dry out to kind a hard, inflexible materials that when re-wetted (or wetted back) putrefies, while tanned materials dries out to a flexible form that does not become putrid when wetted back. The tanning process significantly improves the pure 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 make sure that the leather maintains its interior moisture.
2. It protects the leather from decaying when subjected to water- Chemical therapy 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- Engaged on the leather by way of the tanning processes opens up the leather so that it becomes airy and absorbent.
4. It vastly 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 flexibility of the organic leather– Tanning makes the leather supple and soft improving its workability and moulding qualities. This makes it straightforward to be utilized in the production of leather articles.
Sorts of Tanning Processes
1. Vegetable-tanning: This tanning process includes using 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 colour, with the precise shade relying on the combination of chemical substances and the colour of the skin. It is the only type of leather suitable for use in leather carving or stamping.
Vegetable-tanned leather is just 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 should shrink drastically and partly gelatinize, turning into inflexible and finally brittle.
2. Chrome-tanning: This tanning process was invented in 1858. It is the most generally used tanning process today. It includes using chromium sulfate and other 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. Additionally it is generally known as moist-blue for its colour derived from the chromium. More esoteric colors are potential 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 certain fish oils which have a tendency to supply a very supple, soft and pliable leather like chamois.
5. Combination tanning: This is a tanning method that combines two 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 using the vegetable tanning process. A mix of two tanning techniques is deliberately performed to achieve a very supple leather. Also, leather that is to obtain a finishing technique because of its closing use typically goes by the combination tanning process.