How is fresh raw cowhide processed into genuine leather after depilation and glycolysis?

These are fresh leathers that will be made into top-grade leathers. Before being sent to the leather processing factory, slaughterhouses usually add salt and dry them many times according to the requirements of the factory, so as to inhibit the proliferation of bacteria in fur and affect the quality of hides.

First of all, before kneading the hides, workers should first put all the hides into a stirring tank for hair removal and shearing to remove the fishy smell, redundant cortical fibers and soluble protein, then put them into a mixed solution containing sulfuric acid and salt for cleaning until the PH value in the hides can better absorb the flexible diaphragm, and then transfer them to a drum with gears for continuous rotation for six hours. In this process, leather will become soft and elastic under the softness of rocks, and its color will turn blue and white. Next, the workers will put the blue leather into a roller and roll it repeatedly.

Secondly, this process will not only squeeze out the excess water absorbed by the rawhide when kneading dough, but also peel and delaminate the rawhide at the same time until each rawhide is pressed into a uniform thickness, and then transferred to another mixing barrel to be dyed in different colors according to the requirements of customers. Because the leather has lost most of the oil components before tanning, in order to make the leather more flexible, workers will add different proportions of oil according to different leathers in this process.

Third, next, in order to avoid excessive shrinkage of leather during drying, workers will first coat the dyed leather with a solution of oily starch mixed with water, then stick them on the glass, and then scrape them continuously to make the leather adhere to the glass smoothly. Finally, they will be sent to the dryer to bake for five hours. Before the leathers are completely dried, they can be put into roll coater and sprayed with a wear-resistant and texture-improving coating. After the coating on the surface is dried, the leather surface is softened and polished repeatedly by a special hot rolling mill, which can not only polish the leather, but also make the leather more soft and elastic. Finally, after passing the quality tests such as tensile strength, silk resistance and heat resistance, they can be packaged and sent to major garment factories to make exquisite leather shoes or high-grade leather garments.