Tanning method by using improved-structure chromium-free retanning agent

Abstract

The invention relates to a tanning method by using an improved-structure chromium-free retanning agent, belonging to the technical field of leather treatment. In order to overcome the defects of severe chromium pollution, low shrinkage temperature and low setting point in the retanning process, the invention provides a tanning method by using an improved-structure chromium-free retanning agent. The method comprises the following steps: adding shaving leather into a rotating drum, adding 100-150 wt% of water, regulating the temperature to 25-30 DEG C, adding 1.5-2.0 wt% of coordination polymerization inhibitor, and rotating for 10-30 minutes; regulating the pH value of the bath to at most 3.5, and rotating for 60-90 minutes; adding 1.0-2.0 wt% of tanning-assisting tannin, and rotating for 90-120 minutes; adding a non-chromium metal composite tanning agent and 0.2-0.4 wt% of alkali extractor to perform alkali extraction; and heating to 38-40 DEG C to perform treatment, and carrying out after-treatment to obtain the finished leather product. The tanning agent has the advantages of high setting point and high shrinkage temperature; and the method effectively controls the total chromium content in the wastewater and sludge.

Description

technical field [0001] The invention relates to a chrome-free retanning agent leather-making method with an improved structure, belonging to the technical field of leather treatment. Background technique [0002] In the modern leather industry, chrome tanning agent is a kind of metal salt tanning agent with the most outstanding application performance, which is widely used and occupies a dominant position in the leather industry. However, as we all know, chromium is a heavy metal that will cause environmental pollution. It is difficult to degrade by general biochemical methods and usually accumulates in the environment. Long-term uncontrolled discharge will cause water pollution, affect the growth of aquatic organisms and microorganisms, and destroy the ecological balance. , which is not conducive to self-purification of water bodies; moreover, although trivalent chromium is used for leather tanning, there is a potential danger of generating highly toxic hexavalent chromium ...

AI Technical Summary

Problems solved by technology

Although the use of aldehyde tanning agents mainly uses aldehydes and their modified products, which has little environmental pollution and can be salt-free and non-pickling, but there are shortcomings such as coarse grain, scale, and free formaldehyde; and synthetic tanning Although the shrinkage temperature of the tanning agent is high, it lacks softness and fullness, and the style of the leather is limited. The high content of aldehyde in the wastewater affects the biochemical treatment, and the matching between the two and the chrome tanning process is slightly poor, and the development of supporting materials needs to be strengthened; The shrinkage temperature of leather treated with non-chrome metal compound tanning agent is relatively high, and it has a good match with a complete set of tanning process and materials based on the chrome tanning method. The disadvantage is that the precipitation point of the tanning agent is low