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Acid-free chromic tanning agent and its prepn

A technology of acid chrome tanning agent and chrome tanning agent, which is applied in the field of chrome tanning agent and its preparation, which can solve the problems of many influencing factors, the decrease of leather strength, and easy occurrence of loose surface, etc., and achieve the effect of solving penetration and combination

Inactive Publication Date: 2004-03-17
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] 1. Because the acid used in general pickling will make the bare leather swell, which is not conducive to the penetration of chrome tanning agent, but also seriously damages the collagen fiber of the skin and reduces the strength of the leather. Therefore, it is necessary to add a large amount of neutral during pickling. salt, such as sodium chloride, to inhibit swelling
The neutral salt will dehydrate the bare leather and cause the leather to be flat and thin. At the same time, the addition of a large amount of salt will cause Cl - environmental pollution
[0004] 2. The operation of the traditional pickling tanning process is complicated and there are many influencing factors. For example, because the bare skin is soaked in acid, the alkali must be lifted in the later stage of tanning, and the alkali lifting operation is too fast, which will cause rough blue leather surface and chrome spots. question
[0005] 3. During the pickling process, many acid-soluble and salt-soluble proteins in the skin collagen will be lost, making the finished leather, especially cowhide and sheepskin shoe upper leather, prone to loose surface
[0006] 4. Pickling generally takes 2 to 24 hours, which increases the entire pickling and tanning process cycle
However, this modification method has a complex reaction system, high production cost, and is only suitable for tanning of thinner skins such as sheepskin.

Method used

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  • Acid-free chromic tanning agent and its prepn
  • Acid-free chromic tanning agent and its prepn

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Dissolve 100 parts of sodium dichromate with 200 parts of water in a reactor with a stirrer, a thermometer and a condenser, then add 90 parts of concentrated sulfuric acid and naphthalene sulfonic acid in turn, the amount of naphthalene sulfonic acid and Cr 2 O 3 The molar ratio is 0.4:1, and the temperature is stirred to slightly boil; 25 parts of sugar are dissolved in 50 parts of water, and the reduced chromium compound is added dropwise within 30 minutes, while the reaction solution is still kept slightly boiling; Sodium formate is dissolved in 80 parts of water, the amount of sodium phthalate is the same as that of Cr 2 O 3 The molar ratio of the tanning agent is 1.5:1, and the dropwise addition is completed in 40 minutes, and then reacted at a temperature of 50 DEG C for 4 hours to obtain a liquid product of a non-pickling chrome tanning agent.

Embodiment 2

[0032] Dissolve 100 parts of potassium dichromate with 200 parts of water in a reactor with a stirrer, a thermometer and a condenser, then add 100 parts of concentrated sulfuric acid and benzenesulfonic acid in turn, the amount of benzenesulfonic acid and Cr 2 O 3 The molar ratio of 0.8:1 is 0.8: 1, and the temperature is stirred to slightly boil; then 20 parts of sugar are dissolved in 40 parts of water, and the reduced chromium compound is added dropwise within 40 minutes, while the reaction solution is still kept slightly boiling; Dissolve with 120 parts of water, the amount of sodium acetate and Cr 2 O 3 The molar ratio of the tanning agent is 1.0:1, and the dropwise addition is completed in 30 minutes, and then reacted at a temperature of 60 DEG C for 3 hours to obtain a liquid product of a non-pickling chrome tanning agent.

Embodiment 3

[0034] Dissolve 100 parts of sodium dichromate with 200 parts of water in a reactor with a stirrer, a thermometer and a condenser, then add 110 parts of concentrated sulfuric acid and naphthalenesulfonic acid in turn, the amount of naphthalenesulfonic acid and Cr 2 O 3 The molar ratio is 1.6:1, and the temperature is stirred to slightly boil; then 25 parts of sugar are dissolved in 50 parts of water, and the reduced chromium compound is added dropwise within 50 minutes, while the reaction solution is still kept slightly boiling; Dissolved in 160 parts of water, the dosage of sodium formate and Cr 2 O 3 The molar ratio of the chrome tanning agent is 0.5:1, and the dropwise addition is completed in 50 minutes, and then reacted at a temperature of 70 DEG C for 2 hours to obtain a liquid product of a non-pickling chrome tanning agent.

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Abstract

This invention relates to a nonacid-soaked chrome tanning agent and its preparation method. The said tanning agent would not occur deposition within 1h when its pH value is not larger than 3.2 and the pH value of environment is not less than 8; this not only makes the chrome tanning agent successfully permeate in the softened make hide with pH value of 7.5 round, but also wound not make it become macromolecule too early, and so the contradiation of permeation and combination in tanning is solved to make the naked hide not be acid-socked, and therefor, it has lowered cost, simple process, shortened period and environment pollution prevented.

Description

1. Technical field [0001] The invention belongs to the technical field of leather chemical industry, and in particular relates to a chrome tanning agent which can be used for tanning without pickling after softening bare hides and a preparation method thereof. 2. Background technology [0002] At present, most of the chrome tanning agents used in tanning production are based on the premise of tanning that the bare hide must be soaked in acid after softening. The purpose of pickling is to inhibit the dissociation of carboxyl groups of skin collagen, and the second is to hinder the hydrolysis and polymerization of chromium complexes under the condition of high pH on the surface of the bare skin, so as to facilitate the penetration of tanning agents into the skin and make the tanning proceed smoothly. Therefore, if the bare leather is not subjected to pickling treatment, the surface will be over-tanned or the chrome will be unevenly distributed in the leather, which will lead t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C14C3/06
Inventor 陈武勇陈占光
Owner SICHUAN UNIV