Chrome-free metal composite tanning agent and preparation method thereof

Abstract

The invention discloses a chromate-free metal composite tanning agent, comprising the following ingredients: 27.5-37.5 wt% of tetravalent zircon salt, 2.0-5.0 wt% of trivalent aluminium salt, 2.5-10.0 wt% of 15-45 wt% tetravalent titanium salt, 2.5-7.5 wt% of La-Ce mixed chlorinated rare earth, 0-2.5 wt% of antifreezing agent, and 55-60 wt% of water, wherein, the tetravalent zircon salt is selected from zirconium sulfate, zirconium nitrate or zirconium chloride, the trivalent aluminium salt is selected from aluminium sulfate, aluminium chloride, aluminum potassium sulfate or aluminium ammonium sulfate, the tetravalent titanium salt is selected from titanyl sulfate, titanium sulfate or ammonium titanyl sulfate complex salt, the antifreezing agent is glycol, and the water is deionized water. The invention also discloses a preparation method of the chrome-free metal composite tanning agent. The chrome-free metal composite tanning agent has the advantages of good comprehensive properties, simple production technology, and environmentally friendly; and the preparation method is simple without special devices.

Description

technical field [0001] The invention belongs to the field of leather tanning, and relates to a leather tanning agent used in the leather tanning process and a preparation method thereof, in particular to a non-chrome metal compound tanning agent and a preparation method thereof. Background technique [0002] Tanning is the most important process in the tanning process. [0003] Since Knapp researched and invented the chrome tanning method in 1858, especially since Dennis invented the one-bath chrome tanning method in 1893, because of its simple operation, easy control, and high moisture and heat resistance and stability of the finished leather, it has been widely used in the leather industry. Widely used and dominant. After more than one hundred years of development, the modern tanning industry has formed a complete set of tanning process system based on chrome tanning. However, the chromium utilization rate of the conventional chrome tanning method is only 65%-75%, and a ...

AI Technical Summary

Problems solved by technology

However, there are many deficiencies in aldehyde tanned leather. Aldehydes have been proven to be carcinogenic substances. The use of aldehyde tanning agents often leads to excessive aldehyde content in finished leather.

In addition, if a large amount of aldehyde tanning agents are used in the process of tanning, it will cause great harm to the health of operators. At the same time, aldehydes are biological inhibitors, which are not conducive to the biochemical treatment of sewage and are harmful to the environment.

Therefore, the chrome-free tanning method based on aldehydes and their modified products is difficult to be widely promoted in the leather industry

[0007] Organic phosphorus tanning agents, such as tetrakis hydroxymethyl phosphonium sulfate, the tanned leather has the advantages of soft, plump, bright color, etc., but the disadvantages are also quite obvious

The main disadvantages are: ①It is produced by the reaction of sulfuric acid, formaldehyde and phosphine, and there is a problem of formaldehyde release after use; ②The shrinkage temperature of tanned leather is low, and the maximum does not exceed 85°C; The process and materials are specially adjusted, which complicates the production process; ④ The binding rate with leather is 90% to 95%, and the remaining part is discharged with wastewater, which will cause organic phosphorus pollution to the water body

The disadvantage is that the shrinkage temperature of tanned leather is low (generally around 75°C), it is not washable, and it is easy to fade after soaking in water, making the leather stiff

However, if zirconium tanning agent, aluminum tanning agent, titanium tanning agent and rare earth metal salt are used alone, the performance of leather is not good. Reasonable matching of zirconium tanning agent, aluminum tanning agent, titanium tanning agent and rare earth metal salt makes full use of their respective advantages. It is expected to develop a chrome-free tanning agent that meets environmental requirements and has comprehensive properties close to chrome tanning agents.

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