Leather processing cycle: intermediate phase

In our last article we started to tell you about the leather processing cycle, stopping at the tanned leather, which in our case by carrying out a chrome tanning takes the name of wet blue.

Below we will give you further information on the steps that come after the tanning phase and therefore on the first characterizing transformations made on the leather, depending on the final product to be made.

At this point, the wet blue leather is processed using drums, first for retanning, through which the leather absorbs further tanning and filling substances to give it the desired degree of softness, resistance and structure.
Secondly for dyeing, dipping it in a solution of hot water and dye, based on the desired shade.
And finally for the fattening, with which the characteristics of softness, fullness and hydrophobicity are given to the leather. For this process, oils and fats of organic (animal or vegetable) or inorganic (synthetic and mineral) origin can be used.

Termite these phases, the leather is subjected to drying, to reduce the water content soaked in it.
This process can be done in several ways, including:

• under-vacuum, the hides are introduced one at a time into a machine equipped with large heated stainless steel plates to obtain a double effect of heating and decompression on them

• nailing, which consists in spreading the hides on a frame manually or semi-automatically depending on the machinery used and then nailing them with special pliers along the frame, which will then be transported to the dryer for drying

• chain, the hides are placed in large drying racks usually positioned under the roof of the building, in a well-ventilated department to allow excess moisture present both on the surface of the leather and inside the leather to evaporate in a completely natural way

The result is a product called crust, which now has important structural properties such as water repellency, impermeability to gases, resistance to heat and abrasion.

At this point all that remains is to improve the appearance, moving on to the last finishing phase, where all the desired characteristics of color, brightness, flexibility and touch will be given to the leather.

But we will tell you this in the next article …
Continue to follow us to discover the last phase of the leather processing cycle !!!

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