Leather Manufacturing - The Art of Making Fine Leather

People have been producing and using leather since the dawn of civilization. In previous times, leather figured significantly in developing technologies and mechanics. Since, the creation of synthetic materials, leather is most often found in the aesthetic realms of fashion.

Leather manufacturing can basically be classified into three different stages: the preparatory stage, the tanning and the crusting stages. The preparatory stage is simply where the animal skin is made clean and fresh of hair. This may sound to be trivial, but this holds a lot of importance in reality as the accuracy of the tanning depends heavily on this. The more neat and cleansed the skin at this stage, the more efficient will be the process of tanning.

Processes such as removing hair cutting, splitting, fleshing, degreasing, bleaching and bating are involved in the preparatory stage.

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Tanning is the crucial stage of the entire Leather Manufacturing process. It involves treating the skin with chromium or chromium sulphate. Though, another important reason for tanning is to renovate the protein of the skin into something more stable so that it can be effortlessly used in an array of applications. Thus tanned skin enjoys a huge advantage over the raw skin – the latter becomes decomposed when wetted or re-wetted, while the former does not.

After treating with Chromium, the color of the skin becomes pale blue and so the material at this step is called ‘wet blue’. After the pickling process is over, the pH of the skin is usually between 2.8 and 3.2, signifying that the skin still is highly acidic in character. After treatment with Chromium or its compounds, the material is then drenched in tanning liquor, which is set aside in a big drum. The drum is generally capable of rotating about a fixed axle so that the liquor can soak the entire skin material uniformly.

The worker then has to check frequently to see if the material is getting rightly soaked or not by cutting through the material and observing the level of infiltration. Subsequently, the skin goes through a route called basification, which is purely done to augment the alkalinity of the material up to 3.8 and 4.2. This process facilitates the leather to become more hydrothermally stable and its shrinkage resistance temperature also increases significantly.

Finally, a process called crusting involves mainly the wetting, drying, softening, coloring and neutralizing, etc. The manufacturing methods vary according to the types of leather, such as aniline, chamois, full grain, top grain etc.