CS220723B1 - A method of making a tanning aid - Google Patents

Abstract

The invention relates to the chemical production of tanning auxiliaries used for tanning leather. It solves the problem of producing a special agent for tanning leather. Its use results in greater utilization of mineral tanning agents, especially chromium salts, which are toxic in wastewater. The essence of the invention lies in the fact that a condensate is prepared from phenolic raw materials and it is further sulfonated in an alkaline environment using salts of sulfurous acid and formaldehyde and further neutralized using inorganic and organic acids that are capable of forming complexes with chromium. Partial neutralization is carried out by adding magnesium salts. The invention can be used in all chemical plants producing tanning auxiliaries and the product in all tanneries performing mineral or combined tanning of leather.

Description

The present invention relates to the manufacture of a tanning aid (KPP) for improving the use of chromium compounds in tanning and filling agents.

The KPP production methods used so far make it possible to prepare tanning and bleaching tanning agents or substances which improve the utilization of chromium compounds in tanning. Basic magnesium salts such as magnesium carbonate, oxide or magnesium hydroxide added to tanning baths are most commonly used to improve chromium utilization. These substances gradually dissolve and are carried out by gradual basification of the astounding compounds. To improve the utilization of chromium compounds, naphthalene sulfoacid condensates are used which are applied prior to tanning with chromium salts according to U.S. Pat. AO 180 994 and AO 188 577.

The disadvantage of all these postuipes is that the application of the magnesium compounds sometimes leads to an uneven tanning of the leather accompanied by the formation of harder stains, and in all cases, a filler must be used which does not improve chromium depletion.

The known processes for the production of fillers and bleaching agents prepare a mixed condensate of phenolic raw materials sulfonated with sulfuric acid salts and formaldehyde, e.g. AO 176,386.

Correction of the properties to achieve a greater filling effect can be accomplished by the addition of urea, formaldehyde, sulfuric acid salts and the subsequent addition of aluminum salts.

Some of the disadvantages of the processes used hitherto are eliminated by the process according to the invention, where the improved properties are achieved by neutralizing the alkaline sulfonation mixture with magnesium salts in a molar ratio to phenol C 'of 0.5 to 0.5: 1 in the presence of complexes with trivalent chromium salts. These are especially sulfuric acid, naphthalenesulfoacids, condensed naphthalenesulfoacids, oxalic acid, formic acid or acetic acid, as well as a mixture of organic acids falling off during the paraffin oxidation and the like. The pH of the resulting product is in the range of 3.0 to 6.0.

The preparations thus prepared can be applied both before the tanning itself and after tanning directly into the spent bath. On an operational scale, bath exhaustion can be achieved such that the residual chromium content is at most 0.2 g / l and the resulting leather is light and well filled.

The process according to the invention is illustrated by the following examples, which are only a few of the many possible variants.

Example 1

Into a reaction vessel equipped with a stirrer and a quantity of heating and cooling, submit

1950 hm. parts of phenol and 50 wt. parts of sulfuric acid 96%. Adjust the temperature to 50 degrees Celsius and gradually add 116Q. % of formaldehyde 36%. We maintain the temperature between 60 and 70 ° C. The total condensation time is 120 minutes. The reaction mixture was separated into two layers. Add 500 wt. parts of water, 2000 wt. parts of crystalline sodium sulfite (50%) and add 670 parts of 36% formaldehyde over a period of 20 minutes while heating. Maintain the temperature at 95 to 100 ° C for at least 3 hours. The resulting resin must be soluble in a 2% sulfuric acid solution. Add 200 wt. parts of urea and 274 wt. of formaldehyde 36% and heated at 60 ° C for 30 minutes.

Add a solution of 53 wt. parts of oxalic acid and 46 wt. parts of crystalline magnesium sulfate in 200 wt. parts of water. PH value 0.5 wt. solution of dry matter in distilled water is 3.7. The resulting product is used in the liquid state or spray dried.

Example 2

1330 wt. parts of technical mixture of divalent phenols with the following composition:

water neutral oils vacuum pitch phenol cresols xylenols pyrocatechin methylpyrocatechin methylpyrocatechin

11.6%

3.1% 2.9% 4.0% 3.3%

31.2%

15.2% 28.5% wt.

wt.

wt.

wt.

wt.

wt.

wt.

wt.

T000 wt. parts of crystalline sodium sulfite (50%), adjust the temperature to 50 ° C and gradually add 915 wt. parts of formaldehyde and heat to boiling. Boil for 30 minutes and then add a solution of 200 wt. parts of aluminum sulfate and 740 wt. parts of magnesium sulfate dissolved in 1000 wt. parts of water. Neutralization is completed by 130 masses. parts of sulfuric acid 96%. The resulting product is dried in a spray dryer.

The invention can be used in all synthetic tanning plants as well as in other chemical plants and the resulting product in all tanneries.

Example 1 a d 3

All operations are carried out in a facility capable of working the clearing in a dynamic way. The weight data are calculated in% of the weight of the wort - pigskin, treated by splitting to a thickness of 1.2 mm. Holina prepared by conventional means scrambles flow of water at 35 to 38 ^Q C.

220

Descaling

200% water% ammonium sulfate

0.4% mordant (protease)

0.05% dispersant (Etoxone) and after 0.5 hour movement

0.5% ammonium sulfate and after 3 hours of movement

1.2% formic acid hr movement, then bath sie them

Washing - flow 15 min

Conditioning and tanning

50% water 25 ° C% condensate of phenolic raw materials as described

Claims (2)

Process for the production of a tanner's auxiliary composition based on mixed condensates from monovalent and divalent phenols, their homologs or mixtures of these raw materials, sulfonated with sulfuric acid. their salts and aldehydes, preferably formaldehyde, possibly treated with urea and formaldehyde, which treatment may be carried out in the presence of salts of sulfuric acid or sulfur23 1% interchangeable tannic 6 hours movement 4% basic chromium salt with 26% by weight, θ2θ3 5% condensate of phenolic raw materials as described 30 min movement, still in the morning The waste bath contains 0.19% CraOs / L, the boiling test complies 100% water 30 ° C 0.1% sodium bicarbonate 2 hours movement, the leather is thrown on a tanner's goat, after embedding it is sprinkled and further neutralized and treated according to the normal procedure. Aluminum, characterized in that the neutralization of the alkali sulphonation mixture is carried out with magnesium salts in a molar ratio to phenol of 0.06 to 0.5: 1, in the presence of inorganic and organic acids capable of binding complex with salts of trivalent chromium, preferably sulfuric acid, oxalic acid, phthalic acid, formic acid or acetic acid, to a pH of 3.0 to 6.0.