Preparation method of wet-white leather

Abstract

A preparation method of wet-white leather comprises the following steps: regulating pH of naked leather to a value which is close to an isoelectric point of the leather, and then squeezing water; adding the leather after water is squeezed in a sealing device, adding anhydrous ethanol of which the weight is 2-4 times that of the leather and dehydrating, rotating for 5-240 min and then recycling bath lotion; repeating dehydrating operation for 2-4 times; then preparing a mixed solution of which the polarity is higher than ethanol, dehydrating for 1-3 times, rotating for 30-600 min and then recycling the bath lotion, wherein the use amount of the mixed solution every time is 100-400% of the weight of the leather; and finally, adding an acetone solution of which the weight is 100-400% of the weight of the leather, rotating for 5-240 min and then taking out the leather so as to obtain the wet-white leather, wherein the water content of the leather is lower than 10%. A solvent polarity increasing step-by-step dehydrating mode is adopted, the preparation method is not affected by the original state or thickness of the naked leather, water on the surface of the naked leather and water in the naked leather can be slowly and uniformly replaced out, and therefore, the wet-white leather which has a porous fiber structure and is good in physical and mechanical properties is obtained.

Description

technical field [0001] The invention belongs to the field of leather tanning, and in particular relates to a preparation method of wet white leather. Background technique [0002] Bare hide refers to the raw animal hide that has been removed from the hair, epidermis and subcutaneous tissue, leaving only the dermis, ready for further processing. Bare hides generally include raw hides after the liming process and before the tanning process, such as delimed hides, softened hides, pickled hides, etc. Tanning is the qualitative change process of treating bare leather with tanning agents to turn it into leather, and this tanning effect must be irreversible. The tanned leather has certain moisture and heat resistance stability, certain formability, good air permeability and bending resistance, and has good use value. Different tanning methods are produced by using different tanning agents to obtain the tanned leather. For example, leather tanned with chrome tanning agent is call...

AI Technical Summary

Problems solved by technology

But for the thicker areas such as the buttocks, if you use acetone to dehydrate directly, the surface will be dehydrated too quickly, and the water inside the skin will not be easily removed, so that the dehydration effect will not be good.

Second, if acetone dehydrates too quickly, it is easy to make fiber bundles, fibers, and fibrils shrink too quickly during the dehydration process, reduce the pore structure of the fiber structure, and directly affect the physical and mechanical properties of the leather.

Third, the state of bare skin is different, resulting in the difference in water content and hydrophilicity of bare skin, which directly affects the effect of acetone dehydration

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