阅读说明：本技术 一种含铬磺甲基化双酚s的水溶性合成鞣剂的制备方法 (Preparation method of water-soluble synthetic tanning agent containing chromium sulfomethylated bisphenol S ) 是由 陈治军 陈杰 王晓颖 陈祖武 彭必雨 于 2020-07-21 设计创作，主要内容包括：本发明提供了一种含铬磺甲基化双酚S的水溶性合成鞣剂的制备方法,是以小分子乙醇为溶剂,水为分散剂将双酚S溶解分散在水中,再按一定比例甲醛和亚硫酸盐的作用下进行缩合,得到磺甲基化砜类合成鞣剂,然后采用有机酸进行中和,与铬粉按一定比例复配得到。应用本发明的特点是该砜类含铬合成鞣剂有利于提高皮革对铬的吸收,避免直接铬复鞣,降低了制革废液甚至污泥中的铬含量,给污泥有效处理带来了机会,符合清洁化生产。检测证明该砜类含铬合成鞣剂复鞣的成革在增厚率、柔软度、物理力学性能等方面表现出良好的性能。(The invention provides a preparation method of a water-soluble synthetic tanning agent containing chromium sulfomethylated bisphenol S, which is prepared by dissolving and dispersing bisphenol S in water by using micromolecular ethanol as a solvent and water as a dispersing agent, condensing under the action of formaldehyde and sulfite according to a certain proportion to obtain a sulfomethylated sulfone synthetic tanning agent, neutralizing by using organic acid, and compounding with chromium powder according to a certain proportion. The application of the invention is characterized in that the sulfone chromium-containing synthetic tanning agent is beneficial to improving the absorption of leather to chromium, avoiding direct chromium retanning, reducing the chromium content in tanning waste liquid and even sludge, bringing an opportunity for effectively treating the sludge and conforming to clean production. Detection proves that the finished leather retanned by the chromium-containing sulfone synthetic tanning agent has good performances in the aspects of thickening rate, softness, physical and mechanical properties and the like.)

1. A preparation method of water-soluble synthetic tanning agent containing chromium sulfomethylated bisphenol S is characterized by comprising the following steps: adding 1 mol of bisphenol S (4, 4' -sulfonyl diphenol) into a three-necked flask with a stirrer and a thermometer, adding 0.2 mol of micromolecule alcohol, adding appropriate amount of water, heating to 50 ℃, stirring for 20min, further stirring and adding 1.2-1.5 mol of sulfite and 1.2-1.5 mol of formaldehyde, stirring for 20min to mix uniformly, slowly adding 10% sodium hydroxide to adjust the pH to 11.5-12.0, heating to 105-110 ℃, continuously reacting to a light yellow turbid solution, continuously preserving the temperature for 2-4 h, cooling to 60 ℃, adjusting the pH to 6.5-7.0 with acetic acid, adjusting the pH to 3.5-4.0 with organic acid, continuously stirring until the solution is transparent, adding 1.0-1.5 mol of chromium sulfate hexahydrate solid, supplementing water and stirring for 1-1.5 h to obtain a blue chromium-containing sulfomethylated bisphenol S synthetic tanning agent solution with the solid content of 40-45% and the pH of 3.2-3.4.

2. The method for preparing the water-soluble synthetic tanning agent containing chromium sulfomethylated bisphenol S as claimed in claim 1, wherein: the micromolecular alcohol is ethylene glycol, propylene glycol or butanediol.

3. The method for preparing the water-soluble synthetic tanning agent containing chromium sulfomethylated bisphenol S as claimed in claim 1, wherein: the sulfite is sodium sulfite, sodium bisulfite or sodium metabisulfite.

4. The method for preparing the water-soluble synthetic tanning agent containing chromium sulfomethylated bisphenol S as claimed in claim 1, wherein: the organic acid is 2-hydroxypropionic acid, 3-hydroxypropionic acid or 2, 3-dihydroxypropionic acid.

5. The method for preparing the water-soluble synthetic tanning agent containing chromium sulfomethylated bisphenol S as claimed in claim 1, wherein: the solid content of the product is constant weight substance at 105 ℃.

Technical Field

The invention relates to a special synthetic tanning agent for leather in the field of fine chemical engineering, in particular to a preparation method of a water-soluble synthetic tanning agent containing chromium sulfomethylated bisphenol S.

Background

Currently, in the leather industry, chrome tanning agents are still the first choice of tanning agent materials, whether main tanning or retanning. The reason is that the chrome tanning agent can obtain excellent performances of softness, fullness, high strength, good wet and heat resistance stability and the like compared with other tanning agents. However, in the conventional tanning process, the absorption of the chrome tanning agent is incomplete (generally only 65-75%), and particularly, the unabsorbed chrome is discharged in the retanning process of wet blue leather, so that the chrome content of wet dyeing and finishing waste liquid is increased and the treatment is difficult. Under the current situation that environmental protection and environmental concern are emphasized, the reduction of the consumption or emission of chromium becomes the main trend of tanning.

So far, the commercial metal complex tanning agent is not uncommon, is a synthetic tanning agent with special characteristics in a tanning process, mainly takes the functions of the synthetic tanning agent as well as has the function of metal salt. The application of the chromium metal complex synthetic tanning agent can use a small amount of chromium salt to obviously improve the plump and compact functions of the synthetic tanning agent. Although the compound containing phenolic hydroxyl and the chromium salt can generate coordination, the structure of the synthetic tanning agent and the strength of the metal complex and the function improvement of the final tanning agent have important significance. The good coordination effect can increase the molecular mass of the metal complex tanning agent, and the mutual stability of the two monomers is enhanced. The significance of this stability is that the heat resistance, light resistance and wash-out resistance in leather of the metal complex tanning agent are significantly improved or enhanced.

Disclosure of Invention

The invention provides a method for preparing water-soluble synthetic tanning agent containing chromium sulfomethylated bisphenol S, which is characterized in that a sulfomethylated structure is formed by sulfonation of bisphenol S after formaldehyde substitution to obtain water solubility, and a complex is formed by some added micromolecular organic acid and chromium ions according to a certain proportion, so that the structural stability is increased. Bisphenol a syntans and related metal complexes are important materials for tanning white leather and for enhancing leather plumpness. However, according to REACH regulations, bisphenol a has been used as a banned substance, thereby necessitating the development of bisphenol S tanning agents.

The invention relates to a method for preparing water-soluble synthetic tanning agent containing chromium sulfomethylated bisphenol S, which comprises the steps of adding 1 mol of bisphenol S (4, 4' -sulfonyl diphenol) into a three-necked bottle with a stirrer and a thermometer, adding 0.2 mol of micromolecular alcohol, adding a proper amount of water, heating to 50 ℃, stirring for 20min, further stirring, adding 1.2-1.5 mol of sulfite and 1.2-1.5 mol of formaldehyde, stirring for 20min, uniformly mixing and dissolving, slowly adding 10% sodium hydroxide to adjust the pH value to 11.5-12.0, heating to 105-110 ℃, continuously reacting until the mixture is light yellow turbid liquid solution, continuously preserving the heat for 2-4 h, cooling to 60 ℃, adjusting the pH value to 6.5-7.0 by using acetic acid, adjusting the pH value to 3.5-4.0 by using organic acid, continuously stirring until the solution is transparent, adding 1.0-1.5 mol of chromium sulfate hexahydrate solid, supplementing water and stirring for 1-1.5 h to obtain a lake blue chromium-containing sulfomethylated bisphenol S synthetic tanning agent solution with the solid content of 40-45% and the pH value of 3.2-3.4.

In the present invention: the micromolecular alcohol is ethylene glycol, propylene glycol or butanediol.

In the present invention: the sulfite is sodium sulfite, sodium bisulfite or sodium metabisulfite.

In the present invention: the organic acid is 2-hydroxypropionic acid, 3-hydroxypropionic acid or 2, 3-dihydroxypropionic acid.

In the present invention: the solid content of the product is constant weight substance at 105 ℃.

The invention has the beneficial effects that: the invention utilizes the tanning agent to carry out retanning, can effectively reduce the use of the chrome tanning agent in chrome retanning, greatly reduces the generation of chrome waste liquid, and lightens the pressure of tanning industry on environmental pollution; in addition, there are two distinct advantages to using sulfomethylation instead of sulfonation under acidic conditions as is commonly used: firstly, neutral salt generated by neutralization after sulfonation synthesis is reduced, so that the salt content of the wastewater is reduced, and the wastewater treatability is improved; and secondly, the methylene is connected with the sulfonate to improve the water solubility, so that the reduction of the tanning property of the bisphenol S can be reduced to the greatest extent, and the retanning function and the tanning compactness are improved. The problem of reduced tanning property caused by direct sulfonation of benzene ring is solved.

Drawings

FIG. 1 is a schematic of the structure of a metal complex.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

Adding 1 mol of bisphenol S (4, 4' -sulfonyl diphenol) into a three-necked flask with a stirrer and a thermometer, adding 0.2 mol of ethylene glycol, adding a proper amount of water, heating to 50 ℃, stirring for 20min, uniformly mixing, adding 1.2 mol of sodium bisulfite and 1.3 mol of formaldehyde, stirring for 20min, uniformly mixing, slowly adding 10% of sodium hydroxide to adjust the pH value to 11.5, heating to 105 ℃, keeping the temperature for 2h, cooling to 60 ℃, adjusting the pH value to 7.0 with acetic acid, adjusting the pH value to 3.5 with 2-hydroxypropionic acid, continuously stirring until the solution is transparent, adding 1.2 mol of chromium sulfate hexahydrate solid, supplementing water, and stirring for 1.5h to obtain a lake blue sulfochromium-containing methylated bisphenol S synthetic tanning agent solution with the solid content of 40-45% and the pH value of 3.2-3.4.

Example 2

Adding 1 mol of bisphenol S (4, 4' -sulfonyl diphenol) into a three-necked flask with a stirrer and a thermometer, adding 0.2 mol of propylene glycol, adding a proper amount of water, heating to 50 ℃, stirring for 20min, adding 1.2 mol of sodium sulfite and 1.2 mol of formaldehyde, stirring for 20min, slowly adding 10% of sodium hydroxide to adjust the pH value to 12.0, heating to 110 ℃, keeping the temperature for 2h, cooling to 60 ℃, adjusting the pH value to 7.0 with acetic acid, adjusting the pH value to 3.5 with 3-hydroxypropionic acid, continuously stirring until the solution is transparent, adding 1.0 mol of chromium sulfate hexahydrate solid, supplementing water, and stirring for 1.5h to obtain a lake blue sulfomethylated bisphenol S synthetic tanning agent solution containing 40-45% of solid and 3.2-3.4 of pH.

Example 3

Adding 1 mol of bisphenol S (4, 4' -sulfonyl diphenol) into a three-necked flask with a stirrer and a thermometer, adding 0.2 mol of propylene glycol, adding a proper amount of water, heating to 50 ℃, stirring for 20min, adding 1.5 mol of sodium sulfite and 1.2 mol of formaldehyde, stirring for 20min, slowly adding 10% of sodium hydroxide to adjust the pH value to 11.5, heating to 110 ℃, keeping the temperature for 2h, cooling to 60 ℃, adjusting the pH value to 7.0 with acetic acid, adjusting the pH value to 3.5 with 2, 3-dihydroxypropionic acid, continuously stirring until the solution is transparent, adding 1.0 mol of chromium sulfate hexahydrate solid, supplementing water, and stirring for 1.5h to obtain a lake blue chromium-containing sulfomethylated bisphenol S synthetic tanning agent solution with the solid content of 40-45% and the pH value of 3.2-3.4.

Example 4

Adding 1 mol of bisphenol S (4, 4' -sulfonyl diphenol) into a three-necked flask with a stirrer and a thermometer, adding 0.2 mol of propylene glycol, adding a proper amount of water, heating to 50 ℃, stirring for 20min, adding 1.2 mol of sodium metabisulfite and 1.2 mol of formaldehyde, stirring for 20min, slowly adding 10% of sodium hydroxide to adjust the pH value to 12.0, heating to 105 ℃, keeping the temperature for 2h, cooling to 60 ℃, adjusting the pH value to 7.0 with acetic acid, adjusting the pH value to 3.5 with 2, 3-dihydroxypropionic acid, continuously stirring until the solution is transparent, adding 1.5 mol of chromium sulfate hexahydrate solid, supplementing water, and stirring for 1.5h to obtain a lake chromium-containing sulfomethylated bisphenol S synthetic tanning agent solution with the solid content of 40-45% and the pH value of 3.2-3.4.

Examples of the applications

The usage amount of the chrome-containing sulfomethylated bisphenol S synthetic tanning agent is 15.0 percent of the weight of the blue wet leather, the processing is carried out according to the conventional blue wet finishing process, the chrome content of the waste liquid after retanning is measured, and the result is shown in table 1; the physical and mechanical strengths of the finished leather, such as thickness, softness, tensile strength, and tear strength, were measured according to national standards for shoe upper leather, and the results are shown in table 2.

TABLE 1 chromium content and absorption in retanning waste liquors

Scheme(s)	Amount/% of	Chromium content/g.L-1	Absorption rate/%)
				Chromium powder	4	1.34	63.3
Example 1	12	0.75	80.1
				Example 2	15	0.81	81.4
Example 3	15	0.83	81.6
				Example 4	10	0.91	80.7

TABLE 2 physical and mechanical Properties of finished leather

Scheme(s)	Thickness/mm	Tensile strength/MPa	Tear Strength/(N/mm)	Bursting strength/(N/mm)	Softness/mm
						Chromium powder	1.39	18.1	45.3	359	7.85
Example 1	1.54	20.4	48.7	364	8.80
						Example 2	1.52	21.7	49.3	367	8.78
Example 3	1.56	20.9	48.9	363	8.83
						Example 4	1.50	21.1	49.0	365	8.76

The application result of the material of the invention has the following advantages:

1) according to two indexes of chromium content in the retanning wastewater and chromium absorption rate in retanning, the method has the advantages of improving the chromium absorption of leather, reducing the chromium content in the tannery waste liquid and meeting the requirement of clean production;

2) according to the invention, different organic acids are used for neutralization to form different organic acid salt masking agents, so that the absorption of the leather to chromium is promoted;

3) the finished leather retanned by the material shows good performances in the aspects of thickening rate, softness, physical and mechanical properties and the like, and has excellent retanning effect;

4) the product has larger molecular weight, and the direct rotation time of the rotary drum is 120min when in use. The total time of retanning and alkali extraction of the chromium salt is approximate.

While the invention has been described in terms of its preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.