JPS6040478B2 - Manufacturing method of chromium-aluminum tanning agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a chromo-aluminum pigment.

Currently, as is well known, various types of mirror agents have been proposed and used, but chromium lacquer and varnish lacquer are the most widely used. Chromium sulfates have been used for a long time because of their excellent retrieval effects, and various basic chromium sulfates are known that differ in basicity and chromium content. However, some drawbacks have been pointed out even with such effective chromium admixtures in line with the demands of the times.One of them is that chromium in chromium leather sludge in drainage water has become large due to tightening of pollution regulations in recent years. This has become a problem, and treatments and countermeasures are required, and various studies are being conducted.

To counter this, '1' is the so-called recycling method in which chromium-containing wastewater is returned to the chrome tanning process.

[2- A so-called highly adsorbent chromium granule method that uses a chromium powder that improves chromium adsorption.

■ A method of using the minimum necessary amount of chromium in combination with other lacquers has been proposed, and has been partially implemented.

Second, since it is a chromium compound, it retains the coloring of the leather due to trivalent chromium, which poses a problem in the dyeability of the leather.

In view of these problems, aluminum lacquers, zirconium lacquers, etc. that do not use any chromium compounds have been proposed, but they have not been replaced due to their inferior selection effects. Therefore, among the above-mentioned methods [3], chromium-aluminum based agents are currently being used. One of them was developed in Poland, and is said to be a reaction product of sodium dichromate, aluminum sulfate, sodium bisulfite + formic acid (salt), but the reaction system is extremely complex. There are many problems such as the difficulty in stabilizing the quality and the fact that part of the sodium bisulfite decomposes during the reaction, making it difficult to reduce the hexavalent chromium and adjust the basicity. On the other hand, a method for producing a ternary fin agent of zirconium-aluminum-chromium has been proposed (Japanese Patent Publication No. 471/1983). Among these, an aluminum-chromium mixture is described as a precursor, but since aluminum is present in a larger amount than chrominium, not only is hydroxide likely to be generated during its production, but
The effect of this in and of itself cannot be expected.

In view of the above-mentioned facts, the present invention has researched the effect of chromium-aluminum compounds and found that the effect of chromium-aluminum compounds in a specific ratio is no different from that of chromium alone. It was completed.

That is, the gist of the present invention is that the weight ratio is 0.7.
A chromium-aluminum-based compound characterized by neutralizing with an alkali agent an acidic mixed aqueous solution consisting of a chromium sulfate-containing material, an aluminum salt, and a carboxyl compound in the range of Cr203/A203Mi3 to make it highly basic. This is related to the manufacturing method of the drug.

In the present invention, chromium sulfate-containing substances are referred to as chromium sulfate, basic chromium sulfate, or their sulfate-containing substances, but industrially, sodium dichromate aqueous solution is reduced organically or inorganically in the presence or absence of carboxylic acid. Basic chromium sulfate produced by reduction reaction with an agent is suitable. Next, the aluminum salt is mainly aluminum sulfate, but basic aluminum sulfate, aluminum chloride, basic aluminum chloride, etc. may also be used as necessary.

In addition, as is well known, carboxylic acid compounds are used as masking agents for OH groups during highly basic formation.
For example, formic acid, acetic acid, oxalic acid, succinic acid, glutaric acid,
Examples include adipic acid, phthalic acid, tartaric acid, citric acid, and lactic acid, and they may also be alkali metal salts, alkali metal salts, or ammonium salts, and at least one or two or more of them are selected and used as appropriate. .

Further, the alkaline agent is not particularly limited as long as it neutralizes each of the above-mentioned chemicals to make them highly basic, but for example, caustic alkali, alkali carbonate, alkali bicarbonate, or sodium aluminate can be used.

Among these, alkali bicarbonate is particularly preferred because it is preferable for operation to use an alkaline agent that is as mild as possible.
In the present invention, the above-mentioned chemicals are mixed and reacted in an aqueous solution to produce a demulcent, and the weight ratio of the chromium sulfate-containing substance and the aluminum salt is 0.7 Cr203/A203.
It is essential to set it within the range of 3S3.

The reason for this is that when the value is less than about 0.7, the amount of aluminum in the liquid increases, and even if the masking effect of the carboxylic acid compound is relied upon during basification, aluminum hydroxide is likely to be formed during operation. At the same time that basification cannot be obtained, the manufacturing process becomes extremely laborious, and the resulting product has the unavoidable problem that its performance decreases more than compensating for the drawbacks of chromium. on the other hand, about 3
This is because, if it exceeds 100%, the advantages based on the addition of aluminum will not be obtained so much, and it will not be substantially different from conventional chromium repellents. In addition, the amount of carboxyl acid compound used as a masking agent depends on the desired set basicity, and also varies depending on its type and the quantitative relationship between aluminum and chromium, but in many cases Cr203 10A Part 2
The amount is in the range of 0.3 to 2.5 mol per 0.03.

In this way, a chromium sulfate-containing substance, an aluminum salt, and a carboxylic acid compound are mixed into an aqueous solution in an appropriately set ratio,
Next, the mixture is gradually neutralized with an alkaline agent at room temperature to 80° C. under mixing conditions to make it highly basic. Then,
After the addition of the alkali IJ agent is completed, the mixture is continued to mature for a while, and if necessary, after being filtered, it is spray-dried by a conventional method to form a product into granules.

The particle size of the product is preferably about 40 mesh, which can be dissolved in cold water, but is not limited thereto. In many cases, the composition of the chromium-aluminum type detergent obtained by the present invention is as follows (wt%) (However, as a carboxylic acid compound, HC
(Representatively shown as OONa): Cr203: 2-25%
Preferably 8-20% A203: 2-25% Preferably 5-16% HCOONa: 1-15% Preferably 6-15% However, Cr203/A2Q: 0.7
-3 preferably 0.8-2 Basicity: 20-55% preferably 28-50%.

The chromium-aluminum saddle agent of the present invention thus obtained improves the heat resistance of grass tanned using aluminum only, and also reduces the chromium in wastewater by at least 1/2 of the conventional method.
It has the effect of significantly reducing the chromium contamination load by reducing the amount of chromium contamination to less than 100%, and has various advantages as listed below.

'11 The amount of chromium used can be reduced, reducing the amount of chromium in wastewater. '2l A leather that has the characteristics of both chrome and aluminum leather, that is, its heat resistance is almost the same as chrome leather tanned leather, and the color tone of the tanned leather is less whitish than that of chrome leather tanned leather. Becomes good.

[3] The final result of the technique is a tanned leather that is flexible, has good grain fineness, and has excellent dyeability.

The method of using the chromium-aluminum thickening agent obtained in the present invention is basically no different from that of ordinary chromium thickening agents, and the tanning work is not complicated at all.

The present invention will be specifically explained below with reference to Examples, Comparative Examples, and Test Examples.

Example 1 2563k of water was added to a glass-lined reaction vessel equipped with a thermometer and a rope scaler.
g Basic chromium sulfate 1000k
9 (Nippon Kagaku Kogyo ■ Neochrome ■) Aluminum sulfate 1007k9 (solid A 2
(S04) 357%) Sodium formate
240k9 (powder HCOONa 95%) was taken, added to 60qo, and stirred for 60 minutes.

To this mixture, 282 k9 of bicarbonate of soda was gradually added over 12 μm intervals. At this time, no gel formation was observed and the base could be made highly basic. After the addition, the mixture was filtered in a conventional manner and then dried with Akebono to obtain granular product 2114k9. Product composition is C'2
03 12. Weight%Aso2
〃HCOONa
l0.7 〃Na2S0
The basicity was 422.4 and the basicity was 333, and the water disintegration property was very good.

Example 2 In the same reaction vessel as in Example 1, add 2600 ml of water.
9 basic chromium sulfate 1000k
9 (Nippon Kagaku Kogyo ■ Neochrome ■) Aluminum sulfate 1007k9 (solid A 2
(S04) 357%) Sodium acetate
140k9 (Powder Cucumber COONa Satoshi.5%)
They searched for 60 qo and had a 60 minute rope romp.

Add 120k9 of bicarbonate soda 282k9 to this mixture.
It was added gradually between two females. At this time, no gel formation was observed. After the addition, the mixture was filtered in a conventional manner and then dried to obtain a granular product 2030k9. Product composition is Cr
203 12.5% by weight A〆2〇3 84″C ratio CO
ONa 6.7 〃Na2S04
234″ basicity
33.3, and the water solubility was very good.

Example 3 Water 2750k9 in the same reaction vessel as Example 1
Basic chromium sulfate 1000k9
(Nippon Kagaku Kogyo ■ Neochrome ■) Aluminum sulfate
1007kg (solid A2 (S)
04) 357%) Sodium formate
Searching for 240k9 (powder HCOONa95%),
The mixture was poured into 6p0 and stirred for 60 minutes.

Add 6 parts of bicarbonate of soda to this mixture so that the basicity is 50%.
61k9 was added gradually in 12 flour increments. At this time, no gel formation was observed. After the addition, the mixture was filtered in an oven according to a conventional method and then dried in a fog to obtain 2,307 kg of granular product. Product composition is C [203 11. Weight%A 203 7-4 〃H
COONa 9.8 〃N
a2S04 30.8
The basicity was 50.0.

Comparative Example 1 6287k water in the same reaction vessel as Example 1
9 basic chromium sulfate 1000k
9 (Nippon Kagaku Kogyo ■ Neochrome ■) Aluminum sulfate 3020k9 (solid A2)
(S04) 357%) Sodium formate
240 kg (powdered HCOONa 95%) was taken, added to 60q0, and mixed with a powder for 60 minutes.

The Cr203/A203 ratio at this raw material blending ratio is 0.5
Met. When sodium bicarbonate 1507k9 was gradually added to this mixed solution so that the basicity was 50%, a gel formed before the addition was completed and it was not possible to commercialize the product.

Comparative Example 2 Water 1697k9 in the same reaction vessel as Example 1
Basic chromium sulfate 1000k9
(Nippon Kagaku Kogyo ■ Neochrome ■) Aluminum sulfate
377k9 (solid A evening 2 (S)
Q) 357%) Sodium formate
Search for 60 [9 (powder HCOONa95%),
The mixture was heated to 6,000 ℃ and mixed with 6 powders of Fumata Azusa.

The Cr203/A2Q ratio at this raw material blending ratio was 4. When 185k9 of sodium bicarbonate was added to this mixed solution and the mixture was basified to a basicity of 33.3%, a granular product having the following composition was obtained without generation of gel. C et al.03
18. Weight%A203
4-5 〃HCOONa
4.0 〃N also S04
23.1 Basicity
333 However, the tanning performance of this product was not very different from Test Example 1 below and was not distinctive.

Test Example 1 8 parts by weight and 10 parts by weight of a commercially available basic chromium sulfate admixture agent (Cr203 25.5%, basicity 33.3%) were used for 10 parts by weight of pickled peel (light steer). enemy pm
Soot production was carried out in the usual manner in a drum.

The Cr203 content, heat shrinkage temperature, and Cr2Q content of the tanning wastewater obtained as a result were as follows.
Experimental site. 1 2 Addition amount of chromium agent 8 parts by weight 10″ rear leather C03 content 4.50% 5.
66″ Heat shrinkage temperature 110℃ 1
19″ tanning wastewater C et al.03 containing group 0
．． Spot % 0.67'' The Cr203 content and heat shrinkage temperature were measured in accordance with the JIS K655 grass test method.

Test Example 2 8 parts by weight and 1 part by weight of the chromium-aluminum based repellent produced in Example 1 were used for the same acid-soaked peel 10 as in Test Example 1, and the same method as in Test Example 1 was used. The product was manufactured.

The C03 content of Sunflower obtained as a result, A203
The content, heat shrinkage temperature, and Cr203 content of tanning waste water were as follows. Experiment M. 3
4 Chromium-aluminum-based adhesion agent 8 parts by weight 10"
Tanned leather Cr203 content 2.89%
3.39″A evening 203 〃 1
．． 46〃 1.75″ Heat shrinkage temperature
108qo 118″ Tanning waste water C 03 content
0.07% 0.12″ Test Example 1
When compared with '11, the heat shrinkage temperature is about the same.

■ Cr203 content in tanning wastewater has been reduced to 1/5.

'31 It is clear that the coloring caused by trivalent chromium on the leather becomes lighter and the dyeability is good.

Claims (1)

[Claims] 1 Weight ratio 0.7≦Cr_2O_3/Al_2O_3≦
3. A method for producing a chromium-aluminum tanning agent, which comprises neutralizing an acidic mixed aqueous solution consisting of a chromium sulfate-containing substance, an aluminum salt, and a carboxylic acid compound with an alkaline agent to make it highly basic. 2. The method for producing a chromium-aluminum tanning agent according to claim 1, wherein the chromium sulfate-containing material is a basic chromium sulfate-containing material produced by reducing sodium dichromate. 3. The method for producing a chromium-aluminum tanning agent according to claim 1, wherein the aluminum is aluminum sulfate. 4. The method for producing a chromium-aluminum tanning agent according to claim 1, wherein the alkaline agent is sodium bicarbonate.