The leather that arrives in the tanners, besides having the characteristics of animal, it’s at its natural stage, and therefore, passing of the days of putrefaction.To be able to be worked and preserved raw leather it must necessarily be “tanned” with chemical and mechanical processes on the one hand and with the aid of animal or vegetable origin substances on the other.The treatment of the leather is a procedure very ancient, which dates back to prehistoric times when leathers were used for shelter from weather elements.Still the tanning business is carried out in the traditional way, even though large industries and tanneries use large machines and more specific chemicals.
The tanning process could be synthesized in five phases: preservation, riviera, tanning, post tanning, finishing touch.
PRELIMINARY STAGE OR PRESERVATION
After the animal skinning, the raw leather it is treated with salt to preserve it from bacterial action, during the transport to the tannery. For the treatment of raw leather with salt, it’s used ordinary sea salt, that penetrates the leather to help eliminate some of the water.
In the preliminary phase to the salting, follows the drying, to eliminate the most water possible from the leather, so as to preserve it from the attack of microorganisms and bacteria.
Three main phases, characterize the tanning process:
This is a preparatory stage, where the leather is prepared for tanning.
The name of this phase it remained unchanged, whereas in ancient times, the preparatory activities were carried out for convenience on the river bank.
In Riviera processing is done: revive, liming, fleshing and splitting.
This phase is the core of the leather working. It's a chemical operation which transforms the leather in perishable into an unalterable material.
The tanning process consists of soaking the leather with chemical or vegetable substances that prevent the decomposition without altering the flexibility and the structure.This process is done by putting the leather in a wooden container that rolls.
Here the tanned products eliminate the raw fibres, making the product more durable, softer and especially more resistant for the following processes.
There are different types of tanning:
POST TANNING PHASE:
After tanning, is the following, all the treatments that allow improvement of the leather usable and saleable.
At this stage the leather acquires the characteristics of brightness, colour and appearance you want and it can be mechanical or chemical type.
The mechanical it can be done in different ways:
This technique is used when you want a surface with movement and the flower is evident, this way the leather acquires softness and resistance.
The chemical finishing, instead, consists of coating the surface of the leather with a film, more or less thick, synthetic or natural dyes or paints. These aspects, together with the definition of leather trimmings, are mastered during the ironing and finishing stage.
At this point, before the leather is delivered to the masters, in the tanneries, are done quality controls: for the characteristics of the surface, thickness, as well as physical-chemical test on the basis of national and international standards.
After this analysis of the treatment process and preservation of the leather, you just need to watch the video made by FeniceCareSystem, where you can see concretely which are the processes the leather undergoes, in order to be preserved and processed. GOOD VISION!
Video La lavorazione della pelle e del cuoio : https://www.youtube.com/watch?v=hJyOtb84ctI
* foto di Shafiqbrothers