Synthetic tanning general
In addition to chrome tanning and vegetable tanning, there is a third method used to preserve leather: synthetic tanning. This tanning process uses artificially produced (i.e., synthetic) substances that are not naturally occurring. These tanning agents are as diverse in number as their uses, with the most important being formaldehyde, glutaraldehyde, phenols, and acrylates.
Synthetic tanning agents then and now
After its invention in 1911, this process met with high demand, especially during wartime, when tanning agents and tanning materials were in short supply. Today, synthetic tanning agents are produced from aromatic products using proprietary processes, which is why they are often referred to as aromatic syntans. Their popularity in the chemical industry is on a par with that of vegetable tanning agents. Approximately 200,000 tons of synthetic tanning agents are produced annually.
Properties of synthetically tanned leather
"Wet white" is the name given to synthetically tanned leather due to its light color when it is still wet and undyed immediately after tanning. This type of leather is often used for car seats, for example. The disadvantage: synthetically tanned leather is particularly sensitive to moisture and heat. If it comes into contact with liquid, it absorbs into the leather. In combination with heat, this often causes the soft material to harden or shrink.
Synthetic retanning
Synthetic tanning is therefore rarely performed in isolation, but usually in combination with vegetable tanning or chrome tanning. In the synthetic retanning of leather tanned with chrome salts, the synthetic tanning agents fill the otherwise empty or light leather.
Additional sources (accessed 05.12.2018):
- leder-info(dot)de/index.php/Synthetische_Gerbung
- lederzentrum(dot)de/wiki/index.php/Synthetische_Gerbung
- softart-leder-shop(dot)de/btc/leder-lexikon/begriff/synthetische+tanbung
- lederpedia(dot)de/lederherstellung/tanning/tanning_with_synthetic_tanning_agents
