tannins

Tannins General

Tanning agents, or chemically known as polyhydroxy compounds, are characterized by their ability to alter the properties of protein structures, causing them to become cross-linked. The proteins denature and, as a result, lose their original functions in animal hides. The result is hard-wearing, durable leather. The preservation of leather using various tanning agents has been practiced since the early Middle Ages.

Tanning agents Gusti Leather

Effects of tannins

In addition to preservation, tanning agents have other positive effects on the finished leather. After tanning, the hides have increased temperature tolerance and reduced swelling capacity. The denaturation of the protein chains also causes the hides to dehydrate, causing them to shrink and become firmer.
Tannins are divided into two different classes: natural (vegetable) tannins and artificial tannins.

Tanning agents-Gusti-Leather5c18ccfb1cff8

Natural tannins

Tanning with animal-based, fatty tanning agents such as tallow, marrow, brain, or oil to preserve the leather. However, this type of tanning does not always produce leather-like results.
Tannins are secondary plant substances and are only produced in certain cell types. We find tannins in a wide variety of trees, shrubs, herbs, fruits, and nuts. They serve as a defense against predators because they bind and precipitate proteins. This can lead to kidney, liver, and stomach upsets, or even death, in affected animals. Tannins are generally harmless to humans.

Natural tanning agents Gusti Leather

Artificial tanning agents

The class of artificial tanning agents includes synthetic and mineral tanning agents. Minerals such as iron, zirconium, aluminum, or trivalent chromium salts are used for tanning. Synthetic substances with a tanning effect include aldehydes (formaldehyde, glutaraldehyde), syntans, and polymers (resins based on acrylates and polyurethanes).

Artificial tanning agents Gusti Leather

Applications of tanning agents in leather production

Today, chromium salts are primarily used for leather tanning for most clothing and shoe uppers. Tanning with vegetable tanning agents is used for belts, soles, and riding leather. Synthetic tanning agents are used in the production of leather car seats. Tanning with fats and oils is used for window and traditional costume leather.

Use of tannins