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A salt-free and pickling-free animal skin chrome tanning method based on the synergistic effect of complex ligands

A synergistic, animal skin technology, applied in the fields of leather chemical industry and leather clean production, can solve the problems of difficult penetration of tanning agents, high price of aromatic sulfonic acid, and inability to improve the degree of chromium crosslinking, so as to avoid the use of neutral salt , achieve direct recycling, significant market acceptability effect

Active Publication Date: 2021-08-13
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the price of aromatic sulfonic acid is higher, the consumption is larger, and it is difficult to be effectively applied and popularized; and the molecular weight of aromatic sulfonic acid is relatively large, and it has certain hydrophobicity, so it is difficult to penetrate evenly in the animal skin, resulting in a decline in the uniformity of chrome tanning; On the one hand, the use of aromatic sulfonic acid alone cannot improve the degree of cross-linking formed by chromium between collagen fibers, and also affects the properties of leather
[0005] In recent years, the non-pickling chrome tanning technology (CN1348994A) has been developed. This method is to directly chrome tan the softened animal skins at a higher pH value (higher than 7) without pickling, avoiding the use of neutral salts. However, it is necessary to use low-alkalinity and high-enveloped chromium powder. For thicker hides, there may be problems such as difficulty in penetrating the tanning agent and the risk of soreness in the center of the hide. Difficulty of Direct Recycling of Waste Liquid and Recovery of Chromium in Waste Liquid

Method used

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  • A salt-free and pickling-free animal skin chrome tanning method based on the synergistic effect of complex ligands
  • A salt-free and pickling-free animal skin chrome tanning method based on the synergistic effect of complex ligands

Examples

Experimental program
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Effect test

Embodiment 1

[0029] Example 1—Clean chrome tanning of cow sofa leather

[0030] The dairy cowhide used as tanning is processed through soaking, dehairing, liming, deliming, and softening processes, and then proceeds to the following two steps.

[0031] (1) Soften bare skin with polychromium ligand treatment

[0032] After soaking, dehairing, liming, deliming, and softening processes, 100kg of dairy cowhide is put into the drum, 50kg of water is added, the temperature is adjusted to 22°C, and 1.8 kg, rotated for 3 hours, the ligand penetrates evenly in the softened bare skin, and the pH value of the bath is controlled at 4.5.

[0033] (2) Pretreatment animal skin chrome tanning

[0034] Add Chromosal B (a basicity of 33%, Cr 2 o 3 Content is 26% chrome tanning agent (Lanxess company) 4.5kg, rotate 180 minutes, after chrome tanning agent has penetrated into skin completely, add 60 ℃ hot water 150kg, bath liquid temperature is 40 ℃, continue to rotate 3 hours, The pH of the bath was stab...

Embodiment 2

[0038] Example 2—Salt-free chrome high absorption chrome tanning of cattle shoe upper leather

[0039] The yellow cowhide used for tanning is processed by soaking in water, dehairing, liming, deliming, and softening, and then proceeds to the following two steps.

[0040] (1) Soften bare skin with polychromium ligand treatment

[0041]After soaking, dehairing, liming, deliming and softening processes, the dairy cow hide is 100kg in terms of the weight of gray hide, put it into the drum, add 40kg of water, adjust the temperature to 20°C, and add polychromium ligand composite material 1.2 kg, rotated for 4 hours, and then intermittently rotated for a total of 10 hours, the composite material was completely and evenly penetrated into the softened bare skin, and the pH value of the bath was controlled at 5.0.

[0042] (2) Chrome tanned

[0043] Add 3.0 kg of DowellorGHL (an electrolyte-resistant fatliquor, Sichuan Dawei Technology Co., Ltd.), rotate for 0.5 hours, add ChromosalB ...

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Abstract

The invention provides a salt-free and non-pickling animal skin chrome tanning method based on the synergistic effect of complex chromium ligands. The feature of this method is to use a variety of ligands with gradient differences in coordination ability with hydrated chromium ions to treat and soften animal skins, effectively control the hydrolysis and polymerization rate of chromium complexes during the chrome tanning process, without pickling operation, and without using Chrome tanning is carried out under the condition of neutral salt and masking agent to realize salt-free and high absorption chrome tanning. The invention solves the problem that under the condition of high pH value, it is difficult to balance the rapid penetration and high-efficiency combination of chromium in animal skin and the degree of chromium crosslinking between collagen fibers is difficult to control, which affects the performance of leather; compared with conventional chrome tanning methods, it can The process operation is simplified, the chromium absorption rate is increased to over 95%, the chromium concentration in the waste liquid is reduced to below 100mg / L, the chrome tanning waste liquid can be efficiently and directly recycled, the generation of chromium-containing sludge is reduced by more than 80%, and the leather has better Softness and fullness. The invention significantly improves the leather-forming performance of salt-free high-absorption chrome tanning.

Description

technical field [0001] The invention relates to animal skin processing technology, in particular to a chromium crosslinking strength control between collagen fibers and a salt-free chromium high-absorption chrome tanning method under high pH value conditions in leather or fur production, which belongs to the field of leather clean production and also belongs to leather In the field of chemical technology, it is suitable for the tanning process of all animal skins. Background technique [0002] At present, more than 85% of the leather is chrome tanned leather, and for a long time, chrome tanning will still be the main leather tanning technology; but chromium is a heavy metal, and its emission is strictly controlled. The chromium absorption rate in the conventional "pickling-mask-chrome tanning" technology widely used at present is only 65%-75%, and a large amount of neutral salt is required, resulting in the concentration of chromium and chloride ions remaining in the waste l...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C14C3/06
Inventor 张春晓彭必雨贾欣驹虞德胜夏聪
Owner SICHUAN UNIV
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