What is leather?
Leather is an animal skin that has been denatured and is not perishable, which is obtained through physical and chemical processing such as dehairing and tanning. Leather is composed of natural protein fibers woven tightly in a three-dimensional space. There is a special grain layer on the surface, which has natural grain and luster, and feels comfortable.
In the process of human evolution, it was discovered that some plant juices or mineral oils have certain tanning properties on leather, and the raw material hides are more breathable and antiseptic through the immersion of the juice. So that the board has physical and chemical properties such as softness, tear resistance, and bending resistance. The leather of this period really possessed the characteristics of leather products. And this kind of juice is called a tanning agent. The tanning agents that formed stable tanning agents during the development of the leather industry in the middle of the last century can be roughly divided into the following three categories:
1. Vegetable tanning agent: mainly tannin extract, used for industrial leather or bottom leather.
2. Mineral tanning agents: mainly chromium salts and aluminum salts, used in various civilian leathers. Such as clothing.
3. Organic tanning agents: mainly formaldehyde, glutaraldehyde, etc., used for fur fur and various fine miscellaneous skins.