Vegetable tanning leather is made of vegetable tanning agent. Vegetable tannin mainly uses vegetable tannin and vegetable tannin. Vegetable tannin is a kind of polyphenol compound which can make leather change from tannin and plant polyphenol.
Vegetable tanning is rich in tannin (tannin > 8%), and has the use value of leather, dried, leaves, fruits, etc. known as vegetable tannins. Among them, the extraction liquid obtained by extracting tannin from vegetable tannin with water is called tannin extract after further treatment. Therefore, vegetable tanning leather tanned by vegetable tanning agent is also called tannin extract. Bark, wood, shell and leaves of plant kingdom are all tannin extract raw materials.