What is the difference between vegetable tanned and chrome tanned leather?

Tanning is an important method in leather
processing, in which vegetable tanning and chrome tanning are the main two processing technologies. From the process of leather treatment, it can be
roughly divided into two kinds. One is the leather tanned from animal skin with
vegetable tannin (astringent), which is called vegetable tanned leather. The
other is a kind of leather material made by tanning animal skin with chemical
adjustment, which is called chrome tanned leather.

Vegetable tanning

Vegetable tanning is to put the raw leather
into a large vat. The main feature of vegetable tanning is that it contains
tannic acid solution elements. Collagen, as we know it, is mainly a kind of
leather produced by the combination and action of a substance from plants. Due
to the requirements of commercial purposes, many tannins are extracted from the
bark or wood layer of some trees that have passed through oak and white
hardwood.

In the process of transferring raw leather
from one VAT to another, the tannic acid solution required will be continuously
enhanced, and in general, tannic acid solution will be used for soaking for a
period of time, such as several weeks. After rinsing, a natural oil can be used
to soak and dry the leather.

Characteristics of vegetable tanned
leather and suitable types of works

Vegetable tanned leather is characterized
by its strong plasticity, firmness and wear resistance. Vegetable tanned
leather has dense fiber tissue and good toughness. The trimming opening can be
directly exposed. After polishing, it will turn dark and show luster (with the
increase of time, the color will become darker with the increase of light).
Vegetable tanned leather will become soft when it is wet. In this state, you
can make modeling at will. And as long as the vegetable tanning material is
dry, it can maintain this shape all the time.Vegetable tanned leather is a kind of stiff
leather material, which is very suitable for making strong and stylish works.
It is widely used in the production of men’s leather goods.

Characteristics of chrome tanned leather
and suitable types of works

At first, the raw material skin can be
pickled in a solution with salt and sulfuric acid for a period of time. After
the solution has completely penetrated into the raw leather, slowly pour in
chromium sulfate, then slowly inject sodium bicarbonate, and then slowly reduce
the acidity of the solution, so that the collagen can react with the chromium
in the solution, and then tanning the raw leather we finally get. It takes an
extra night to remove the water from the raw materials, and it takes an
additional night to tanning.The biggest feature of chrome tanned
leather is that it is soft and elastic, not easy to leave scars and creases,
and not easy to shape in production. Chrome tanned leather cannot show
beautiful texture even after being polished, so it is usually decorated by
dyeing or hidden inside by internal sewing. However, the color and pattern of
chrome tanned leather are more diverse than vegetable tanned leather.Chrome tanned leather is most suitable for
making works that will deform with the loaded items, such as tote bag. This
effect is not achieved by vegetable tanned leather materials. Moreover, because
most chrome tanned leather feels relatively soft, it is very suitable for
making gentle works loved by women.