How Is Leather Made?
Leather is admittedly the most in demand material in the fashion and furniture industry, sought after for its timeless elegance and superior durability. Leather enthusiasts consider as valuable investment their wide collection of exquisite leather home furnishings, ready-to-wear garments, footwear, bags and purses, travel items, sports and fashion accessories, and leather jewelries! The most widely used leather garments by far are the ageless Leather Coats and Jackets, causing quite a craze among the young and old alike. Indeed, Leather wear exudes a distinctive fashion statement but have you ever wondered how this material is made? Of course, everybody knows leather comes from animal hide but most people never really looked into the process involved which converts raw animal hide into the leather we all fancy.
The process of making leather is generally known as Tanning. Actually the manufacturing process of leather involves three major stages, namely, Preparatory Stage, Tanning Stage, and the Crusting Stage. The first stage is where the soaking, liming, un-hairing, fleshing, splitting, bating, degreasing, frizzing, and pickling take place. In the second stage, the actual tanning takes place using several methods, the choice of which is essentially dependent on the end application of the finished leather. Here are several methods to give you a clearer understanding:
Vegetable Tanning: This tanning method uses Tannin, a type of polyphenol astringent chemical where the method got its name. Other ingredients found in vegetable matter, tree bark and similar sources are used as well. Vegetable-tanned leather is the only form of leather appropriate for leather-carving or stamping (giving a three-dimensional appearance). One downside of vegetable-tanned leather is that it tends to discolor if soaked in water and will shrink if in hot water.
Mineral Tanning: This tanning method uses Chromium or Chromium Sulfate. Unlike vegetable-tanned leather, the product of this method does not discolor when soaked in water. It is more supple and pliable and is also referred to as “wet-blue”, the color derived from Chromium. Another mineral used under this method is Glutaraldehyde or Oxazolidine known as Aldehyde Tanning and is referred to as “wet-white” due to its pale color. It is commonly used in automobiles and infant shoes. Chamois falls under this category.
Tawing: This tanning method uses Alum and Aluminium salts, mixed with other proteins like flour and egg yolk. Technically, Alum-Tanned leather is not considered tanned as the resulting material will decay if soaked in water for some time.
Brain Tanning: This tanning method is rather tedious involving a labor-intensive process using emulsified oils of animal brains. Brain-tanned leather is exceptionally soft and can be washed.
In the final stage of the leather manufacturing process, the Crusting Stage, the hide is thinned, re-tanned and lubricated. It may likewise undergo wetting back, neutralization, re-tanning, dyeing drying, conditioning, and buffing. In certain instances, a fourth stage is necessary for particular types of leather where the materials are applied with a surface coating. This is otherwise referred to as the Finishing. In the finishing operations, the leather is oiled, brushed, buffed, sprayed, roller coated, polished, embossed, ironed, combed or glazed. The finished Leather is now in its finest form, ready to be made into various leather products.
