In preparation for leather finishing in tanneries, leather drying and leather conditioning are both delicate and crucial activities to obtain a perfectly workable product.
Both stages focus on leather moisture and air humidity control: specifically, leather drying is needed to eliminate the excess water, while conditioning is necessary to re-hydrate the leather as well as to stabilize the chemical products used in retanning and sometimes finishing.
As most leather making steps, drying and conditioning come with a few difficulties tanneries have to deal with: first of all, the loss of quality and area yield of the leather.
But is it possible to define a balance between leather drying and leather conditioning parameters, in order to get the best quality and the most quantity of the finished leather?
The leather drying process
Leather drying is a decisive step in giving specific chemical and physical properties to the product. It can take place in drying tunnels by controlling the environment temperature and humidity.
Different leather drying methods directly influence the surface area of the product, a crucial aspect for tanneries: obtaining as much usable area of leather as possible means making the best use of the product in both commercial and sustainability terms.
As a hydrophilic material, leather inevitably tends to shrink in the absence of water. This is even more problematic in leathers produced with different tannages to chrome tanning, like vegetable tanning, wet white or sustainable tanning agents which are becoming increasingly popular and necessary.
If not carried out properly, leather drying can cause serious aesthetic damages and an excessive reduction of area yield, worsening the overall leather quality: these are some of the major obstacles that R&D leather drying laboratories are still trying to solve.
The leather conditioning process
Similarly, leather conditioning is a fundamental process in order to preserve the most area yield of the finished leather. The main goal of leather conditioning is to rebalance the moisture lost during drying, in order to increase leather’s quality and resistance.
A leather conditioning machinery can reintroduce water by managing the temperature and humidity of the working environment. But leather conditioning is also influenced by other factors like seasonality, climate and even geographic latitude, which tannery equipment and leather processing machines are often unable to manage.
In leather finishing and conditioning, the main goal of tanneries is to achieve the complete standardization in leather production and to guarantee the best final result.
To improve leather production’s reproducibility, leather preconditioning is a technique that may be used to better control the humidity in which the leather is stored. However, this method is often not compatible with industrial leather production practices.
Leather drying and conditioning: techniques, challenges and opportunities
Leather drying and conditioning has been known for a long time in the tanning industry, as have the many parameters of leather processing used in tanneries, that are often handed down through generations or discovered through empirical tests.
At the same time, however, obtaining the best qualitative and quantitative result in leather processing remains one of the many challenges to face. Some common techniques are:
Longer leather drying periods at lower temperatures;
Leather preconditioning phases;
Specific leather retanning treatments.
However, it is not always possible to apply them.
Consequently, Fratelli Carlessi undertook a study together with the Institute of Creative Leather Technology of Northampton, to study these phenomena and develop new leather drying and conditioning systems to transform the whole tanning industry.
MCC and CRC systems: achieving maximum leather yield and quality
MCC and CRC are our most modern leather drying and conditioning systems. Versatile and automated, CRC and MCC machineries for tanneries can achieve uniform and repeatable results, regardless of leather volumes or types.
By combining an independent cells system with a sophisticated air flow control, it is possible to process leather in a short time by alternating cycles of preconditioning, drying and conditioning at low temperatures, reducing working time and energy consumption.
Processing all types of leathers: leathers with smooth or pebbled grain, chrome-tanned or metal-free, of different batches and with different characteristics;
Automation of leather preconditioning, drying and conditioning cycles;
Reduced times and consumption in leather drying compared to traditional systems;
Reproducibility of leather processing to get the most area yield and quality;
Independency from variables such as seasonality, environment and latitude.
The balance between leather drying and leather conditioning lies in innovative solutions and technologies, capable of giving tanneries the total control of leather processing, in order to obtian the maximum quality and surface yield possibile.