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 History
Even prehistoric man had developed primitive methods of treating hides and and skins so that they could be used for clothing. Although at first the raw hides were dried and preserved by smoking, man soon discovered the tanning effect of certain barks and woods
Soaking
The hides and skins lose a good deal of their natural moisture as a result of the curing process. The main object of soaking therefore, is to restore the lost moisture so that the chemical treatments that follow will achieve optimum results
Liming
The following objective s are acheived in the liming process:
Unhairing - to remove the epidermic layer and to loosen the hair,Removal of intertibrillary proteins(cementing substances), Swelling of fiber bundles into individual fibers and splitting of fibers into into fibrils,and To remove the natural fats in leather by saponification
Deliming
The alkaline chemicals used in the liming process are still present in relatively large amounts in two forms. a)partly as free alkali and b)partly as chemically combined with collagen. Now that their utility is served, they should be removed. Free alkali which is soluble in water is removed partially bywashing the pelts in water. After washing, chemically combined alkali is removed by neutralising it.
Bating
The main object of bating is to make the grain surface clean, smooth and fine and give the finished leather its soft, pliable and stretchy feel.
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Sheep
Pickling
Delimed and bated pelts are no subjected to a PICKLING process. The first object is to condition the pelts for chrome tanning; the other to preserve delimed; and bated pelts either for tanning at a later stage or for export.
Tanning
The next step in the leather-making process after pickling is tanning-or the conversion of putrescible animal skins or hides into a stable commercial product-leather
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Neutralisation
TThe process of de-acidification of chrome leather is known as Neutralisation. The basic chrome salt bound by hide protein in a wet condition hydrolyses and liberates further quantity of acid, getting itself more basic and fixing on to the hide fibers more firmly....
Fatliqour
The history of Leather-the need, the origin, the trends, the improvement,
Dyeing
The history of Leather-the need, the origin, the trends, the improvement,
Finishing
The history of Leather-the need, the origin, the trends, the improvement,
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