Ammonium salt-free and boric acid-free leather deashing agent

A deliming agent and ammonium-free technology, applied in leather surface treatment, small raw hide/big raw hide/leather/fur treatment, small raw hide/large raw hide/leather skin/fur chemical treatment, etc., can solve cushioning or penetration Poor performance, reducing the effect of biological treatment of wastewater, etc., to achieve the effects of easy operation and control, realization of resource utilization, and reduction of ammonia nitrogen pollution

Pending Publication Date: 2019-02-26
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The deliming agent can solve ammonium salt deliming will produce a large amount of irritating ammonia gas and high concentration ammonia nitrogen wastewater, boric acid deliming will reduce the biological treatment effect of wastewater, acetic acid, citric acid, succinic acid, carbon dioxide, magnesium salt, esters, etc. The technical problem of poor pH buffering or permeability of existing cleaning and deliming agents

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] In parts by weight, put 100 parts of chopped gray skin scraps, 100 parts of water and 2 parts of acetic acid in the reactor, adjust the temperature to 35°C, react for 1.5h, filter and collect the gray skin scraps, add 250 parts 8mol / L hydrochloric acid, adjust the temperature to 110°C, hydrolyze for 8 hours, filter and collect the filtrate, deacidify the filtrate and decolorize it with activated carbon, and finally adjust the pH of the filtrate to 5~6 to obtain a liquid deliming agent, or dry the liquid deliming agent Afterwards, solid deliming agent is obtained;

[0024] The relative molecular mass of the deliming agent is 196g / mol;

[0025]Put the liming bare hide into the drum, add 100wt% water and 4wt% deliming agent (based on solid content) based on the mass of the liming bare hide, adjust the temperature to 32°C, and rotate for 60 minutes to obtain the delimed bare hide. Skin.

Embodiment 2

[0038] In parts by weight, put 100 parts of chromium-containing waste leather scraps, 150 parts of water, 5 parts of sodium hydroxide and 1 part of magnesium oxide in a reactor, adjust the temperature to 90 ° C, hydrolyze for 6 hours, filter and collect the filtrate, and finally Adjust the pH of the filtrate to 5-6 to obtain a liquid deliming agent, or dry the liquid deliming agent to obtain a solid deliming agent;

[0039] The relative molecular mass of the deliming agent is 1058g / mol;

[0040] Put the liming bare hide into the drum, add 200wt% water and 8wt% deliming agent (based on solid content) based on the mass of the liming bare hide, adjust the temperature to 35°C, and rotate for 30 minutes to obtain the delimed bare hide. Skin.

Embodiment 3

[0042] In parts by weight, put 100 parts of unhaired, washed and chopped raw hides and 300 parts of water in the reactor, adjust the pH to 8, add 3 parts of trypsin, adjust the temperature to 37 ° C, and hydrolyze for 3 hours. Then adjust the pH to 6.5, add 1.5 parts of protamex protease, adjust the temperature to 50°C, hydrolyze for 6 hours, raise the temperature to 80°C, inactivate the enzyme for 15 minutes, filter and collect the filtrate, and finally adjust the pH of the filtrate to 5~6 to obtain liquid deliming agent, or dry the liquid deliming agent to obtain a solid deliming agent;

[0043] The relative molecular mass of the deliming agent is 1912g / mol;

[0044] Put the liming bare hide into the drum, add 50wt% water based on the mass of the liming bare hide and 1.5wt% deliming agent (based on solid content) to adjust the temperature to 25°C, turn it for 20 minutes and then adjust it to intermittent Rotate, and the total time is 120min to obtain the delimed bare hide. ...

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PUM

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Abstract

The invention discloses an ammonium salt-free and boric acid-free leather deashing agent. The ammonium salt-free and boric acid-free leather deashing agent is characterized by being a low-relative molecular mass hydrolysate obtained through deep hydrolysis of collagen as a raw material under a suitable condition. The ammonium salt-free and boric acid-free leather deashing agent can form a buffering system with the pH of 8-9 together with ash alkali in ash leather, and quickly permeates into the ash leather to obtain soft deashed naked leather. The ammonium salt-free and boric acid-free leatherdeashing agent can solve the technical problems that a lot of irritating ammonia gas and high-concentration ammonia nitrogen wastewater are produced during ammonium salt deashing, the biological treatment effect of wastewater is reduced during boric acid deashing, and the existing ammonium salt-free and boric acid-free deashing agent has poor pH buffering and permeability, and is an environment-friendly, easily-controlled-operation, economical and practical deashing agent.

Description

technical field [0001] The invention relates to an ammonium-salt-free and boric-acid-free leather deliming agent, which belongs to the field of raw hide deliming. Background technique [0002] Deliming is an important process accompanied by liming in the tanning preparation section. Its main purpose is to remove the ash and alkali in the liming bare hide, reduce the pH of the gray hide, and basically eliminate the swelling of the gray hide. Create suitable conditions for the smooth progress of subsequent processes. Ammonium salts (ammonium sulfate and ammonium chloride) have the advantages of good pH buffering, fast penetration and low price, and are the most commonly used deliming agents in tanning enterprises. However, deliming with ammonium salts will not only release a large amount of ammonia gas with a strong pungent smell, endangering the health of operators, but also greatly increase the ammonia nitrogen content of tanning wastewater. Due to the difficulty and high ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C14C11/00
CPCC14C11/00
Inventor 曾运航雷超石碧王亚楠周建飞
Owner SICHUAN UNIV
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