Combination tanning

Combination tanning General

Among other factors and steps in the leather production process, the type of tanning primarily determines the final properties of the leather. By combining different tanning methods, desired properties can be enhanced or reduced. The success of combination tanning or mixed tanning depends on the correct order in which the different tanning agents are applied to the hide. Attention must also be paid to the speed and quantity with which the subsequent tanning agents are absorbed into the leather.

Combination tanning Mixed tanning Gusti Leather

Types of mixed tanning

Possible types of combination tanning are:

Vegetable tanning + subsequent chrome tanning = semi-chrome
Chrome tanning + subsequent vegetable tanning = retanned chrome leather
Mineral tanning with formaldehyde + subsequent tanning with lye = combined tanning with lye

For example, the tanner labels the finished tanned leather with the addition “4% chromium + 22% vegetable tanning agent”.

Mixed tanning Combination tanning Gusti Leather

Retanned chrome leather

Probably the most popular form of mixed tanning is the retanning of chrome leather with vegetable tanning agents. The goal of this combination is to combine the positive properties of chrome tanning (strength, heat resistance, dyeability) with the positive properties of vegetable tanning (embossability, fullness). To achieve consistently good results, the chrome-tanned leather must be deacidified before retanning.
Retanned chrome leather is used in industry primarily as shoe upper leather, clothing leather and waterproof leather.

Retanned leather

Semi-chrome leather

Re-chroming vegetable-tanned leather is another form of mixed tanning. The goal of retanning is to improve color, softness, and heat resistance. This combination tanning process is primarily used for apparel leather to achieve a softer, fuller feel. Semi-chrome leather has better abrasion resistance, which is why it is often used in sole leather production.

Semi-chrome leather