Tanning is the process of getting 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 won’t rot. The principal distinction between uncooked hides and tanned hides is that raw hides dry out to type a hard, inflexible materials that when re-wetted (or wetted back) putrefies, while tanned material dries out to a flexible kind that doesn’t change into putrid when wetted back. The tanning process significantly improves the natural qualities of the leather similar 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 at all times be sure that the leather maintains its internal 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 as a result 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 strength of the leather- Tanning builds up resilience within the leather. This makes the full grain leather resist all kinds of climate conditions.
5. It enhances the flexibleness of the leather- Tanning makes the leather supple and soft bettering its workability and moulding qualities. This makes it easy to be utilized within the manufacturing of leather articles.
Sorts of Tanning Processes
1. Vegetable-tanning: This tanning process includes the use of tannins and different ingredients present 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 color, with the precise shade depending on the combination of chemicals and the color of the skin. It’s the solely form of leather suitable to be used in leather carving or stamping.
Vegetable-tanned leather will not be 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 hot water, it will shrink drastically and partly gelatinize, changing into inflexible and eventually brittle.
2. Chrome-tanning: This tanning process was invented in 1858. It’s the most widely used tanning process today. It includes the use 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’s also often known as wet-blue for its color derived from the chromium. More esoteric colors are attainable 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 provide a very supple, soft and pliable leather like chamois.
5. Mixture tanning: This is a tanning approach that combines two or more of the above tanning strategies discussed. Largely, it’s 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 mix of tanning techniques is deliberately carried out to achieve a really supple leather. Also, leather that’s to obtain a finishing approach because of its last use generally goes through the combination tanning process.