Tanning agent-free tanning method

A technology of tanning agent and polar organic solvent, applied in the field of leather making, can solve the problems of non-recyclability, unfavorable industrialization, solvent discharge, etc., and achieve the effects of improving the efficiency of tanning, reducing the cost of tanning, and shortening the tanning time.

Active Publication Date: 2021-08-17
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, polar organic solvents after dehydration have a high water content and cannot be reused for dehydration of pelts, thus causing problems of low solvent utilization and solvent emissions
On the other hand, the existing tanning agent-free tanning technology uses in-situ hydrolysis to enhance the surface roughness of dehydrated hides to achieve hydrophobic treatment. This technology requires accurate control of the degree of in-situ hydrolysis, which is not conducive to industrialization

Method used

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  • Tanning agent-free tanning method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Tanning-free tanning:

[0046] Dehydrate the bare hide (cowhide) in absolute ethanol (6.0 times the weight of the bare hide) for 90 minutes, add molecular sieve activation powder (3A) (3.5 times the weight of the bare hide) and dehydrate for 120 minutes to obtain the dehydrated hide. Adopt Karl Fischer method to measure its moisture content to be 2.95%;

[0047] Dry the dehydrated skin to obtain the skin base, and the softness of the skin base measured according to GB / T 39371-2020 is 4.69 mm, as shown in Table 3;

[0048] Weigh silicon dioxide (10% of the weight of the skin) and disperse it in absolute ethanol (10 times the weight of the skin) to form a suspension, then filter the above suspension onto the surface of the skin, dry it and place Soak in 10 wt% PDMS solution (8.0 times the weight of the skin) for 5.0 min to complete the hydrophobic treatment;

[0049] Tanning agent-free leather is obtained after drying the above-mentioned skin base that has completed the...

Embodiment 2

[0061] The molecular sieve recovered in Example 1 and ethanol are used to form a molecular sieve-polar organic solvent composite dehydration medium for reuse in the tanning agent-free tanning of this embodiment:

[0062] Put the bare hide (cowhide) into recovered ethanol (6.0 times the weight of the bare hide) for dehydration for 90 minutes, add the recovered molecular sieve activation powder (3A) (3.5 times the weight of the bare hide) and dehydrate for 120 minutes to obtain dehydrated Skin, adopting Karl Fischer method to measure its water content is 3.24%;

[0063] Dry the dehydrated skin to obtain the skin base, and measure the softness of the skin base to be 4.52 mm, as shown in Table 3;

[0064] Weigh silicon dioxide (10% of the weight of the skin) and disperse it in absolute ethanol (10 times the weight of the skin) to form a suspension, then filter the above suspension onto the surface of the skin, dry it and place Soak in 10 wt% PDMS solution (8.0 times the weight of...

Embodiment 3

[0069] Dehydrate the bare hide (cowhide) in absolute ethanol (4.0 times the weight of the bare hide) for 60 minutes, add molecular sieve activation powder (3A) (2.0 times the weight of the bare hide) and dehydrate for 60 minutes to obtain the dehydrated hide. Adopt Karl Fischer method to measure its moisture content to be 3.48%;

[0070] Drying the dehydrated skin to obtain the skin base;

[0071] Weigh titanium dioxide (8.0% of the weight of the skin) and disperse it in absolute ethanol (12 times the weight of the skin) to form a suspension, then filter the above suspension onto the surface of the skin, dry it and place it at 10 Soak in wt% PDMS solution (5.0 times the weight of the skin) for 30 minutes to complete the hydrophobic treatment;

[0072] The leather without tanning agent was dried after the hydrophobic treatment was completed. The mechanical performance parameters of the tanning agent-free leather prepared in this example are shown in Table 2, the tear force is ...

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Abstract

The invention belongs to the technical field of tanning, and discloses a tanning agent-free tanning method. Firstly, a molecular sieve-polar organic solvent composite dehydration medium is used for carrying out controllable dehydration on naked skins; and then, the tanning-agent-free leather is prepared by increasing the surface roughness of the leather blank and reducing the surface energy of the leather blank. No metal or non-metal tanning agent is used, and the method has the advantage of being environmentally friendly; according to the invention, distribution balance of water between the pelt and the polar organic solvent is broken, multi-medium self-driven directional controllable dehydration of water in the pelt from the raw hide to the polar organic solvent and then from the polar organic solvent to the molecular sieve is realized, and continuous controllable removal of water in the raw hide is promoted. The problems that when a pure polar organic solvent is used for dehydrating the bare leather, the dehydration efficiency is low, bath changing dehydration is needed for multiple times, organic waste liquid is difficult to recycle and the like are effectively solved, a molecular sieve-polar organic solvent dehydration system is easy to recycle and can be circularly used for controllable dehydration of the bare leather for multiple times, and a brand-new clean leather making technology is provided.

Description

technical field [0001] The invention relates to the technical field of leather making, in particular to a method for making leather without tanning agents. Background technique [0002] Chrome tanning has always been dominant in the tanning industry (Yao Q, Chen H, Jiao Q, et al. Hydroxyl‐Terminated Dendrimer Acting as a High Exhaustion Agent for ChromeTanning[J]. ChemistrySelect, 2018, 3(4): 1032-1039. Ding W, Cheng Y, Wang Y, et al. Chrome-reduced combination tanning for cleaner dyed sheep furprocessing[J]. Journal of the American Leather Chemists Association, 2015,110(11): 363-371.) . However, chrome tanning requires the use of large amounts of chromium salts, sulfates, and chlorides. At the same time, trivalent chromium Cr(Ⅲ) has the risk of being oxidized to hexavalent chromium Cr(Ⅵ) during neutralization, fatliquoring, dyeing and other post-tanning processes and storage (Tang Y, Zhou J, Zeng Y, et al. Effect of leather chemicals on Cr(III) removal from post tanning ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C14C1/00C14B1/58C14C9/00
CPCC14C1/00C14B1/58C14C9/00C14C11/003C14C13/00C14C9/02C09D183/04
Inventor 黄鑫黄亚文石碧
Owner SICHUAN UNIV
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