Fabrication |
Drying |
On the setting-out machine, the sides are flattened and stretched out on the grain side by a setting-out cylinder with blunt blades.
So, the leather surface becomes smoother and more even.
12. Vacuum dryer
During vacuum drying, the sides are placed with the grain side down on a plate with a temperature of 40° centigrade.
Under the influence of a vacuum, the leather is further dehumidified.
The leathers are slightly dried, and the fibers are fixed by doing so.
13. Hang Dry
The leathers are not yet fully dried.
The last drying process is carried out by hang drying.
Here, any remaining moisture in the leathers evaporates.
Chemical reactions in the hide now have enough time to take place, and the moisture within the hide has time to spread evenly.
By removing moisture, the chemicals added before connect better with the skin fibers. This raises the fastness and later gives the leather a more comfortable feel.
The energy needed for the drying process is taken from the waste heat generated by other processes – ensuring that there are no unnecessary CO2 emissions.
The energy needed for the drying process is taken from the waste heat generated by other processes - ensuring that there are no unnecessary CO2 emissions.
In contrast to the general trend in the leather industry, hang drying is given a lot of time at the Heinen tannery - because high-quality leather has to ripen.
The natural structure of the hide needs time to adjust to the different processes that have been carried out.
Just like wine ageing in a bottle, freshly tanned leather needs a time to rest.
Feel, technical, and visual characteristics are improved.
14. Damping
After the leathers have been dried, they are dampened once again, since the water is needed as
”fibre lubrication” for the next production step.
Because the leathers have been given water-repellant characteristics, dampening the leather is not easy.
The leathers need to sweat under a clingwrap; thereby, fragmented water steam diffuses into the gaps within the leather.
