Leather is made from animal skins processed by a series of physical and chemical methods. The process of making leather from raw hides (the original skins peeled off from animals) is called tanning.

Tanning is a relatively complex process with a relatively long cycle. Generally, the tanning process is divided into three stages: preparation stage, tanning stage, and finishing stage.

(1) Main processes in the preparation stage

The main processes include soaking, meat removal, hair removal, liming, degreasing, softening, and pickling. The main role of the preparation stage is to remove some ingredients from the raw leather that are not beneficial to tanning, such as fur, blood stains, fat, and some soluble proteins. The collagen fibers of the original skin are loosened and softened to facilitate subsequent processing.

(2) Tanning stage

The main processes include pre tanning, tanning, and retanning. This stage is a key stage in tanning,

Through the tanning process, the structure of collagen fibers has undergone a change, namely, from raw leather (raw leather) to leather that can be stored for a long time and has functional uses.

(3) Finishing stage

The main processes include chipping, neutralization, dyeing, fatliquoring, drying, spreading, buffing, finishing, and embossing. This stage mainly involves finishing the tanned leather to obtain different designs and colors of leather. For example, leather with different colors and patterns is obtained through dyeing, finishing, and embossing, and leather with different thicknesses and softness is obtained through shaving, fatliquoring, and filling.