Chromium-free dyeing method for leather

By using a combination of specific dyes and additives, the pH value is regulated and the step-by-step addition of formic acid is solved, the deep permeability, uniformity and environmental protection problems in chromium-free dyeing technology are achieved, and efficient chromium-free leather dyeing is achieved to meet industrial requirements.

CN120331037APending Publication Date: 2025-07-18LIRONG SHOES SHENZHEN CO LTD
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Patent Information

Application Number
CN202510673318.4
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-05-23
Publication Date
2025-07-18

AI Technical Summary

Technical Problem

The existing chrome-free dyeing technology is difficult to meet the industrial requirements of deep permeability, uniformity, color fastness and environmental protection at the same time, and there are problems such as poor permeability of dyes, weak binding strength, poor auxiliary compatibility and unstable dyeing process.

Method used

Azo-β-ketone main dye and anthraquinone-amino acid copolymerization and dispersion dye are used, combined with permeation synergistic agent, saturation lifting agent and uniform dyeing agent, and formic acid is added step by regulating the pH value of the dye bath solution and adding formic acid in steps to promote uniform penetration of the dye and fix it on the leather fibers. A neutralizing additives are used to improve the fiber affinity, and EDTA-2Na and weak anionic surfactant are added to remove metal ions.

Benefits of technology

It achieves the deep uniform penetration of dyes and high color fastness in the leather, reduces dye spots and color flowers, and has no chromium ions in the wastewater, complies with environmentally friendly emission standards, and improves dyeing quality and environmentally friendly performance.

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Abstract

The invention relates to the technical field of leather dyeing, and discloses a chromium-free dyeing method for leather, which comprises the following steps: adding 30-35 DEG C deionized water and crust leather into a rotary drum, adding 1.5% of sodium formate, 0.6% of sodium bicarbonate and 0.2% of neutralizing aid, adjusting the pH value to 5.3-5.5, rolling for 60 minutes, and draining; intermittently washing the leather for 2-4 times by using deionized water at 60-65 DEG C; cooling to 30-33 DEG C, sequentially adding 0.3% of ammonia water, 1% of a permeation synergist, 6% of a main dye, 2% of a saturation improver, 2% of a disperse dye and 0.6% of a leveling agent, and carrying out roll dyeing; adding 0.3% formic acid in four times, rolling for 10-20 minutes each time, adjusting the pH value, and continuously rolling for 30 minutes; and finally, washing twice with deionized water, and discharging from the drum after 8-12 minutes. The method realizes deep and uniform penetration of the dye, has high color fastness, is chromium-free and environment-friendly, and significantly improves the leather dyeing quality and environmental protection performance.
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