Tanning General
Fish oil tanning is a type of fat tanning in which leather is tanned using animal oil. The resulting leather is also called chamois leather. Sheep and lambskins, in particular, are often tanned with fish oil (fish oil). The fish oil used usually comes from cod, less frequently from seals or whales. Fish and aquatic mammals contain a high concentration of unsaturated acids in their fatty substances, which combine with oxygen (oxidation) and produce the tanning effect. This effect is lacking in the fats of land animals, which is why tanning with these animal fats is referred to as "false tanning."
Process and phases of tanning
Hides tanned using blubber are called chamois leather. Unlike the preservation of oil-cured leather, the production of chamois leather takes significantly longer, approximately 6-9 months. The process consists of two phases. In the first phase, the hide is drummed in a barrel of blubber oil. This is followed by the drying phase, during which the blubber bonds with the leather fiber. The two phases are repeated alternately. After oxidation, the excess fat is washed out using soda water.
Properties of chamois leather
Tanning can be performed either alone (genuine chamois) or in a combination tanning process (new chamois). New chamois leather is pre-tanned with formaldehyde and post-tanned with tannin. Important properties of chamois leather include its softness, ease of cleaning, absorbency, and temperature resistance up to 70°C. Chamois-tanned leather has a dark brown color after the tanning process, which is often bleached with hydrogen peroxide.
Use of chamois leather
Not only sheepskins and goatskins, but also wild animals are tanned with blubber oil. If the grain layer is removed from deer or stag hides, the finished product is suede. Chamois leather from red deer is primarily used for traditional clothing or gloves. Chamois-tanned leather is also used in orthopedics, where it is characterized by its washability, sweat resistance, and softness. This type of leather is also often used as chamois leather and for cleaning purposes.
Additional sources (accessed 07.12.2018):
- oeko-fair(dot)de/clever-consumption/clothes-decoration/leather/production6/tanning/fat-tanning
- de(dot)wikipedia(dot)org/wiki/S%C3%A4mixed leather
- lederzentrum(dot)de/wiki/index.php/S%C3%A4mischleder
