CS272112B1 - A method of making a combined tanner - Google Patents

Abstract

Production of a combined tanning agent by mineralization of condensates of naphthalene mono-, di- and trisulfonic acids using trivalent chromium salts such as hydroxide, sulfates, chloride or alum in an amount of 3 to 15% by weight of chromium oxide based on the dry matter of the product. The above process can be used in the production of tanning auxiliaries.

Description

The present invention relates to a process for the production of a tanning aid with the combined action of a synthetic tanning aid and chromium salts.

The tanning aids used to accelerate tanning of leather or tanning of chromium salts use, in addition to the basic raw material, which is a condensate of naphthalene mono-, di- and trisulphonic acids, also decalcified sulphite extracts, up to a maximum of 25% by weight. dry weight of the condensate of naphthalene mono-, di- and trisulphonic acids, or sulfinic extracts modified by heating to 80 to 130 ^° C and oxidation of decalcified or unweighted sulfinic leachate in an amount of 35 to 400% by weight of dry matter of modified sulfinic extracts to dry matter of naphthalene sulfoic acid condensate. At the same time, a maximum of 30% by weight of tannins produced by condensation of phenols, sulfonated phenols and bethanaphthol sulfonate can be added. All these preparations of other preparations in the stated amount modify the properties of the basic condensate of naphthalene sulfoic acids. With the current shortage of raw materials made from naphthalene, the production of these tanning aids is also limited. The addition of weak organic acids, such as formic acid, acetic acid, propionic acid, sialic acid, and many others, is also used to improve the properties of these compositions. These acids are also deficient and expensive.

Some of the disadvantages of the production methods used hitherto are eliminated by the production process according to the invention, which consists in the heat treatment of condensates of naphthalene mono, di- and trisulfonic acids or their mixtures and formaldehyde in an acidic medium for 30 to 120 minutes at a temperature of 50 to 120 minutes. 100 ° C, with the addition of chromium salts of the general formula

Cr (OH) _n (SO ₄ ) _{(3n) / 2} 'or Cr (OH) _n Cl. x HgO, where M can be Na mono-, di- and trisulfone chromium sulfates. Addition% wt. Cr ₂ 0j.

, where n = 0 to 3 or with salts of the type MCr (SO ₄ ) ₂ · or K or NH 4. Alternatively, the condensation of naphthalene acids, or mixtures thereof, with formaldehyde in the presence of chromium salts is such that the dry matter of the product contains 3 to

Inorganic acids or alkalis are added to the mixture thus obtained in such an amount that the theoretical basicity of the chromium salts contained in the product is 75 ° of Schorlemmer.

The prepared product can be applied in a liquid state or it can be dried, for example, in a spray dryer. Substances which gradually weigh acidity in an amount of up to 10% by weight, per dry matter of the product, can be added to the dried product. Optionally, the substance can be dried before basification and the resulting powder can be mixed with solids gradually weighing acidity in an amount of up to 10% by weight, to the dry matter of the product.

This tanning preparation can be used in all tanning operations in which chromium tanning preparations are used.

The process according to the invention is illustrated by the following examples, which are several of the many possible variants of use.

and

CS 272112 Bl

Example 1

In a reaction vessel equipped with a stirrer, a reflux condenser and the possibility of heating and cooling, we present 3,210 parts by weight of naphthalene mono-, di- and trisulfonic acid condensate or a mixture thereof with formaldehyde, add 471 parts by weight of sulfuric acid and gradually add 1,331 parts, parts of waste chromium hydroxide. Do not dilute the mixture with 1 * 500 parts by weight of water and stir at boiling point for 60 minutes. The pH value of 0.5% by weight of the dry product solution of the finished product must be in the range of 2.8 to 3.3. The theoretical basicity of the chromium salts contained in the product is 33 ° Schorlemmer (corresponding to the formula CrOHSO 2). Dry the finished product in a spray dryer.

Example 2

Into a reaction vessel equipped with a stirrer, a reflux condenser and the possibility of heating and cooling, 1,300 parts by weight of a solid mixture of naphthalene mono-, di- and trisulfonic acids or a mixture thereof with a dry matter content of 95% by weight, with an acid number of 345, and 160 parts by weight are introduced. , parts by weight of 10 wt. The reaction mixture begins to boil and after the addition of formaldehyde is complete, heat to a temperature of 110-115 ° C for a further 3 hours. We cool to a temperature of 60 [deg.] C. and, while constantly cooling, add 400 wt.%, Parts of water and 820 wt., Parts of sodium hydroxide, 40% by weight. The pH of the 0.5% w / w dry product solution is in the range of 3.2 to 3.6. Dry the finished product in a spray dryer.

Example 3

The raw materials are introduced into the reaction vessel as in Example 1. After reaching a temperature of 80 DEG C., 2,600 parts by weight, parts of chromium chloride with a dry matter content of 48% by weight, are metered in successively. Heat the mixture to boiling and stir for 90 minutes. The pH value of 0.5% by weight of dry matter is adjusted to 2.8 to 3.2 with sodium hydroxide.

Example 4

We add 3,210 parts by weight of naphthalene mono-, di- and trisulfonic acid condensate to the reaction vessel, add 230 parts by weight of sulfuric acid and 300 parts by weight of formic acid and gradually add 1,500 parts by weight of chromium alum. The mixture is diluted with 1,000 parts by weight of water and stirred at 100 DEG C. for 90 minutes. The pH of the 0.5% w / w dry matter solution of the product is adjusted to soda in the range of 3.0 to 3.3.

Claims (1)

OBJECT OF THE INVENTION Process for the preparation of a combined tanning agent from naphthalene mono-, di- and tri-sulfonic acids, or mixtures thereof, prepared by condensation with formaldehyde in an acidic medium, characterized in that the condensates are heat-treated at a temperature of 50 to 100 ° C for 30 to or Cr (OH) _n Cl (, _ _n ), or K ⁺ or NH 4, in inorganic acids 120 minutes with chromium salts of the general formula Cr (OH) _n (30 $) ^ _ _n / ₂ , where n = 0 to 3, or with salts of the type MCr (SO ₄ ) ₂ · xH ₂ 0, where M is Na ⁺ amount 3 to 15 wt. Cr ^ -j to the dry matter of the product, and alkalis are added in such an amount that the theoretical basicity of the chromium salts contained in the product is up to 75 ° Schorlemmer.