EP0007555B1 - Application of water-insoluble aluminium silicates to the manufacture of leather - Google Patents

Description

The invention relates to the use of water-insoluble, preferably water-containing aluminum silicates of the general formula (Kat _{2 / n} O) _{X. A)} , ₀₃ . (SiO ₂ ) y,
in the cat an alkali metal ion and / or a divalent and / or a trivalent cation, n a number from 1-3, x a number from 0.5-1.8, y a number from 0.8-50, preferably 1, 3-20 mean, with a particle size of 0.1 µ to 5 mm, which have a calcium binding capacity of 0-200 mg Cao / g of anhydrous active substance, in connection with carboxylic acids containing ester and / or urethane and / or amide groups in leather production .

One of the most current problems in leather production is the partial or complete replacement of auxiliaries that heavily pollute the wastewater of the factories. In addition to degreasing and pre-tanning pimples, this is particularly the case when tanning fur skins and leather. In addition to the tanning agents, other auxiliaries such as solvents and degreasing agents, tensides, electrolytes, phosphates, neutralizing agents etc. are used in the processes of leather production.

From US-A-2359472 the production of solid compositions having a tanning effect is known, the Na-AI silicates precipitated as tanning agents with a ratio of Al _z 0 ₃ : Si0 ₂ such as 1.2-1.5, and a ratio of Na ₂ 0: AI ₂ 0 _{3 have} no greater than 1.5. To avoid difficulties in the acidic medium, organic compounds capable of hydrogen bonding, such as certain esters, amides, alcohols, ketones or phosphoric acid esters, are added to the composition. The composition is applied dissolved in acid.

FR-A-2354383 claims a process for tanning hides and / or leather, using a tanning agent and at least one carboxylic acid which has an ester and / or urethane and / or amide function.

The aim of the invention is to improve the known tanning processes, in particular the use of chemicals and the wastewater load in leather production are to be reduced. For this purpose, according to the invention, certain aluminum silicates are used in combination with carboxylic acids containing ester and / or urethane and / or amide groups, which allow a considerable reduction in the auxiliaries commonly used, in particular chromium tanning agents, and, as a result of their ecological safety, lead to a substantial improvement in the wastewater situation .

By far the most important type of tanning is chrome tanning. It is based on the formation of an azide complex and the agglomeration of the basic chromium salts with the carboxyl groups of the collagen.

In addition, other basic metal salts such as those of iron, aluminum, zircon, titanium and silicon have tanning properties. In practice, however, only certain aluminum and zirconium salts have been used as combination tanning agents. Silicon compounds are practically not used because the starting materials, usually special water glasses, are difficult to handle in the acidic tanning medium. In addition, the leather quality, especially after aging, is usually inadequate, since hardening, a brittle feel and loss of tear resistance can occur.

• Durch eine Verminderung der Menge an Chromgerbstoffen sowie eine sehr hohe Chrom-Auszehrung der Gerbbrühen, wobei eine Reduzierung des Restchromgehaltes der Flotten bis auf 0,2 g/I Chromoxid zu erzielen ist, wird eine erhebliche Entlastung der Abwässer der Gerbereien erreicht. Bereits der alleinige Einsatz der Aluminiumsilikate bringt eine beachtliche Reduzierung des Restchromgehaltes der Flotten, die aber durch die Kombination der Aluminiumsilikate mit den ester- und/oder urethan- und/oder amidgruppenhaltige Carbonsäuren noch wesentlich verbessert werden kann. Diese hohe Chromauszehrung der Gerbbrühen bringt neben der Entlastung der Abwässer zusätzlich einen wirtschaftlicheren Einsatz der Chromgebstoffe.

The use of aluminum silicates in combination with carboxylic acids containing ester and / or urethane and / or amide groups, particularly in the case of chrome tanning or combination tanning with chrome, aluminum and silicon tanning agents, leads to the following advantages:

• By reducing the amount of chromium tannins and a very high chromium consumption of the tannins, whereby the residual chromium content of the liquors can be reduced to 0.2 g / l chromium oxide, the wastewater from the tanneries is considerably relieved. Even the sole use of aluminum silicates brings about a considerable reduction in the residual chromium content of the liquors, but this can be significantly improved by combining the aluminum silicates with the carboxylic acids containing ester and / or urethane and / or amide groups. This high chromium exhaustion of the tannins not only relieves the wastewater, but also makes the chromium substances more economical to use.

The penetration and distribution of the combination tanning agents in the skin is increased, the disadvantages of the usual silicon tanning agents being avoided, since the aluminum silicates in the acidic medium present in the tanning process have pH values of around 3-4.5 to form aluminum salts and polymeric silicas dissolve finest distribution.

In combination tanning, the aluminum silicates are self-dulling due to their own acid consumption. It is therefore not necessary to use additional blunting agents. The tanning liquor shows improved stability when dulling and the tanning of the skins is increased. Overall, the process control for tanning becomes more flexible and safer.

In summary, it can be stated that when the certain aluminum silicates according to the invention are used in combination with carboxylic acids containing ester and / or urethane and / or amide groups, better leather quality, an improvement in the economy of the chrome tanning process and a reduction in the environmental impact are achieved.

The ester and / or urethane and / or amide Group-containing carboxylic acids can be used together with the aluminum silicates in the chrome tanning of leather. Advantageously, however, the carboxylic acids mentioned can already be added in the strongly acidic pimple, that is, before the actual tanning begins, since this achieves a high chromium content in the leather with a particularly uniform distribution.

Suitable ester or urethane and / or amide group-containing carboxylic acids to be used according to the invention are those which have molecular weights of about 170-30000, preferably 310-10000 and have at least 2 carboxyl groups per molecule.

erhalten. Das Molgewicht der resultierenden Produkte beträgt im allgemeinen mehr als 170 und weniger als 100000; die Substanzen enthalten mindestens 2 COOH-Gruppen.The products to be used for the process according to the invention can be prepared by processes known per se (cf., for example, BE Müller, Houben-Weyl, “Methods of Organic Chemistry”, Vol. XIV / 2, 1963, p. 16 ff). The carboxy-containing products are accordingly by reacting compounds containing hydroxyl and / or amino groups in a molar ratio

receive. The molecular weight of the resulting products is generally more than 170 and less than 100,000; the substances contain at least 2 COOH groups.

Since these compounds never clearly condense to the theoretically calculable products during polycondensation, the formation of even higher molecular weight products cannot be ruled out.

However, products which are more than 90% in the molecular weight range 170-30000 and particularly preferably in the range 310-10000 are preferred.

• X-COOH

wobei

• X für folgende Reste stehen kann:
  
  
  
• in diesen Formeln bedeuten
• a und b ganze Zahlen von 0 bis 100, bevorzugt von 1 bis 20.
• k und ganze Zahlen von 0 bis 6, wobei k und I im allgemeinen weniger als 6 oder gleich 6 ist n ganze Zahl von 0 bis 20
• R - (CH₂)_n-; gegebenenfalls alkylsubstituierter Phenylrest,
• R' - (CH₂)_n-C(CH₃)-.-(^CH ₂)_n-R" R oder R'
• R" ' Rest eines mehrwertigen Alkohols z. B.
• Sorbit, Glycerin, Trimethylolpropan
  
  Als Ausgangssubstanzen eignen sich gegebenenfalls halogenierte Polycarbonsäuren, vorzugsweise Dicarbonsäuren wie z. B. Adipin-, Glutar-, Oxal-, Malon-, Malein-, Terephthalsäure, Phthalsäure, Isophthalsäure, Bernsteinsäure, Fumarsäure, Asparaginsäure, Glutaminsäure.

The resulting substances can e.g. B. with the following general formula:

• X-COOH

in which

• X can represent the following residues:
  
  
  
• mean in these formulas
• a and b are integers from 0 to 100, preferably from 1 to 20.
• k and integers from 0 to 6, where k and I are generally less than 6 or equal to 6 n are integers from 0 to 20
• R - (CH ₂ ) _n -; optionally alkyl-substituted phenyl radical,
• R '- (CH ₂ ) _n -C (CH ₃ ) -.- ( ^CH ₂ ) _n -R "R or R'
• R "'residue of a polyhydric alcohol e.g.
• Sorbitol, glycerin, trimethylolpropane
  
  Halogenated polycarboxylic acids, preferably dicarboxylic acids such as, for. B. adipic, glutaric, oxalic, malonic, maleic, terephthalic acid, phthalic acid, isophthalic acid, succinic acid, fumaric acid, aspartic acid, glutamic acid.

The following substances can be used as the hydroxy compound: alcohols such as alkanols, alkenols, alkynols, diols, polyols, amino alcohols, ether alcohols. Glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, dibutylene glycol, polybutylene glycol, amino ethanol, N-alkyl-diethanolamine, stearyl alcohol, oleyl alcohol, e.g. Related to sorbitol.

Compounds containing amido or urethane groups are also suitable for the process according to the invention. For example, Compounds as used for the production of polyester amides, such as diaminoethane, aminoethanol, diaminopropane, diaminohexane, diaminocyclohexane, diaminodicyclohexylmethane.

Suitable carboxylic acids containing ester, urethane or amide groups are obtained, for example, by reacting in each case 2 mol of adipic acid or terephthalic anhydride or dimethyl malonate with in each case 1 mol of diethylene glycol or dipropylene glycol or 1,6-hexanediol or 1,12-octadecanediol or hexamethylenediamine, or 5 mol of adipic acid or terephthalic anhydride with 3 moles of trimethylolpropane, etc. The polyesters can also continue, for example be reacted with glutaric acid or ammonia. Further examples of suitable compounds can be found in DE-A-2626430, pages 12-17.

The carboxylic acids containing ester, urethane or amide groups can be used with particular advantage together with di- and / or tricarboxylic acids and / or their water-soluble hydrolyzable partial esters in chrome tanning. Examples of such compounds are aliphatic and / or aromatic carbon acids with 2-8 C atoms in the chain, such as succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, aspartic acid, glutamic acid, phthalic acid, terephthalic acid, citric acid. These acids can also be used in the form of their hydrolyzable partial esters, for example with mono- or polyhydric alcohols with 1-6 C atoms, such as methanol, ethanol, n- and isopropanol, butanols, amyl alcohols, ethylene, propylene-butylene glycols, glycerol, Trimethylolpropane, pentaerythritol, sorbitol. The monoesters of di- or trivalent acids are preferred, since they hydrolyze relatively quickly in the acidic medium, for example pickle or tanning liquor.

The aluminum silicates to be used according to the invention are amorphous, crystalline, synthetic and natural products which meet the conditions mentioned above. Of particular importance are the products in which, in the general formula Kat, an alkali metal ion, preferably sodium ion, x is a number from 0.7-1.5, y is a number from 0.8-6, preferably 1.3-4 whose particle size is 0.1 to 25 u, preferably 1-12 u and which have a calcium binding capacity of 20-200 mg CaO / g of anhydrous active substance. The same importance should be attached to the products which correspond to the mentioned ones in the meaning of cat, x, y and the calcium binding capacity and differ only by a particle size of more than 25 µ to 5 mm.

Alkali aluminum silicates of this type can be prepared synthetically in a simple manner, for example by reaction of water-soluble silicates with water-soluble aluminates in the presence of water. For this purpose, aqueous solutions of the starting materials can be mixed with one another or a component present in the solid state can be reacted with the other component present as an aqueous solution. The desired aluminum silicates are also obtained by mixing the two components present in the solid state in the presence of water. Al (CH) ₃ , Al ₂ 0 ₃ or SiO _z can also be reacted with alkali silicate or. Prepare aluminate solutions of alkali aluminum silicates. Finally, substances of this type also form from the melt, but because of the high melting temperatures required and the need to convert the melt into finely divided products, this process appears to be less interesting economically.

The alkali aluminum silicates produced by precipitation or converted into aqueous suspension in a finely divided state by other processes can be converted from the amorphous to the aged or to the crystalline state by heating to temperatures of 50-200 ° C. The amorphous or crystalline alkali aluminum silicate present in aqueous suspension can be separated from the remaining aqueous solution by filtration and at temperatures e.g. Dry 50-800 ° C. Depending on the drying conditions, the product contains more or less bound water. Anhydrous products are obtained at 800 ° C. However, the water-containing products are preferred, especially those obtained when drying at 50-400 ° C., in particular 50-200 ° C. Suitable products can be based on their total weight e.g. Have water contents of approx. 2-30%, mostly approx. 8-27%.

Precipitation conditions can already contribute to the formation of the desired small particle sizes of 1-12 µ, whereby the mixed aluminate and silicate solutions - which can also be fed into the reaction vessel at the same time - are exposed to strong shear forces, e.g. the suspension is stirred intensively. If crystallized alkali aluminum silicates are produced - these are preferably used according to the invention - the formation of large, possibly penetrating crystals is prevented by slowly stirring the crystallizing mass.

Nevertheless, undesirable agglomeration of crystal particles can occur during drying, so that it may be advisable to use these secondary particles in a suitable manner, e.g. B. to remove by wind sighting. Alkaline aluminum silicates obtained in the coarser state, which have been ground to the desired grain size, can also be used. For this purpose, z. B. mills and / or air classifiers or combinations thereof.

in der Kat ein Alkalikation, vorzugsweise ein Natriumkation, darstellt. Es ist vorteilhaft, wenn die Alkalialuminiumsilikat-Kristallite abgerundete Ecken und Kanten aufweisen. Will man die Alkalialuminiumsilikate mit abgerundeten Ecken und Kanten herstellen, so geht man mit Vorteil von einem Ansatz aus, dessen molare Zusammensetzung vorzugsweise im Bereich

liegt,wobei Kat_2ln die oben angegebene Bedeutung hat und insbesondere das Natriumion bedeutet. Dieser Ansatz wird in üblicher Weise zur Kristallisation gebracht. Vorteilhafterweise geschieht dies dadurch, dass man den Ansatz wenigstens ½ Stunde auf 70-120°C, vorzugsweise auf 80-95°C unter Rühren erwärmt. Das kristalline Produkt wird auf einfache Weise durch Abtrennen der flüssigen Phase isoliert. Gegebenenfalls empfiehlt es sich, die Produkte vor der Weiterverarbeitung mit Wasser nachzuwaschen und zu trocknen. Auch beim Arbeiten mit einem Ansatz, dessen Zusammensetzung wenig von der oben angegebenen abweicht, erhält man noch Produkte mit abgerundeten Ecken und Kanten, insbesondere, wenn sich die Abweichung nur auf einen der oben angegebenen vier Konzentrationsparameter bezieht.Preferred products are e.g. B. synthetically produced crystalline alkali aluminum silicates of the composition

in the cat represents an alkaline cation, preferably a sodium cation. It is advantageous if the alkali aluminum silicate crystallites have rounded corners and edges. If you want to produce the alkali aluminum silicates with rounded corners and edges, it is advantageous to start from an approach whose molar composition is preferably in the range

is, where Cat _{2ln has} the meaning given above and in particular means the sodium ion. This approach is brought to crystallization in the usual way. This is advantageously done by heating the batch to 70-120 ° C., preferably to 80-95 ° C., with stirring, for at least ½ hour. The crystalline product is isolated in a simple manner by separating the liquid phase. If necessary, it is advisable to wash and dry the products with water before further processing. Even when working with an approach, the composition of which differs little from that specified above, products with rounded corners and edges are still obtained, especially if the deviation only relates to relates to one of the four concentration parameters given above.

Furthermore, according to the invention it is also possible to use finely divided water-insoluble alkali aluminum silicates which have been precipitated and aged or crystallized in the presence of water-soluble inorganic or organic dispersants. Products of this type are accessible in a technically simpler manner. Suitable water-soluble organic dispersants are surfactants, non-surfactant-like aromatic sulfonic acids and compounds with complex formation capacity for calcium. The dispersants mentioned can be introduced into the reaction mixture in any manner before or during the precipitation, for example presented as a solution or dissolved in the aluminate and / or silicate solution. Particularly good effects are achieved when the dispersant is dissolved in the silicate solution. The amount of the dispersant should be at least 0.05% by weight, preferably 0.1-5% by weight, based on the total amount of precipitation. For aging or crystallization, the precipitate is heated to temperatures of 50-200 ° C. for 1 / 2-24 hours. From the multitude of usable dispersants e.g. Sodium lauryl ether sulfate, sodium polyacrylate, hydroxyethane phosphonate and others to name a few.

Eine weitere Variante der erfindungsgemäss einzusetzenden feinteiligen, wasserunlöslichen AIkalialuminiumsilikate stellen Verbindungen der Formel

dar. Bei der Herstellung derartiger Produkte geht man von einem Ansatz aus, dessen molare Zusammensetzung vorzugsweise im Bereich

liegt. Dieser Ansatz wird in üblicher Weise zur Kristallisation gebracht. Vorteilhafterweise geschieht dies dadurch, dass man den Ansatz unter kräftigem Rühren wenigstens ½ Stunde auf 100-200°C vorzugsweise auf 130-160°C erwärmt. Das kristalline Produkt wird auf einfache Weise durch Abtrennen der flüssigen Phase isoliert. Gegebenenfalls empfiehlt es sich, die Produkte vor der Weiterverarbeitung mit Wasser nachzuwaschen und bei Temperaturen von 20-200°C zu trocknen. Die so getrockneten Produkte enthalten noch gebundenes Wasser. Stellt man die Produkte in der beschriebenen Weise her, so erhält man sehr feine Kristallite, die sich zu kugeligen Partikeln, eventuell zu Hohlkugeln von ca. 1 bis 4 p. Durchmesser zusammenlagern.A particular variant of the crystal structure of the alkali aluminum silicates to be used according to the invention is represented by compounds of the general formula

A further variant of the finely divided, water-insoluble aluminum aluminum silicates to be used according to the invention are compounds of the formula

The manufacture of such products is based on an approach whose molar composition is preferably in the range

lies. This approach is brought to crystallization in the usual way. This is advantageously done by heating the batch to 100-200.degree. C., preferably 130-160.degree. C., with vigorous stirring for at least ½ hour. The crystalline product is isolated in a simple manner by separating the liquid phase. If necessary, we recommend washing the products with water before further processing and drying them at temperatures of 20-200 ° C. The products dried in this way still contain bound water. If the products are produced in the manner described, very fine crystallites are obtained which form spherical particles, possibly hollow spheres of approximately 1 to 4 p. Store the diameter together.

zu, wobei Kat ein Alkalikation, insbesondere ein Natriumkation bedeutet. Die Herstellung der Alkalialuminiumsilikate aus calciniertem Kaolin führt ohne besonderen technischen Aufwand direkt zu einem sehr feinteiligen Produkt. Die hydrothermale Behandlung des zuvor bei 500 bis 800°C calcinierten Kaolins mit wässrigem Alkalihydroxid wird bei 50 bis 100°C durchgeführt. Die dabei stattfindende Kristallisationsreaktion ist im allgemeinen nach 0,5-3 Stunden abgeschlossen.Alkali aluminum silicates which can be produced from calcined (destructured) kaolin by hydrothermal treatment with aqueous alkali hydroxide are also suitable for the use according to the invention. The formula comes to the products

to, where cat is an alkaline cation, in particular a sodium cation. The production of the alkali aluminum silicates from calcined kaolin leads directly to a very finely divided product without any special technical effort. The hydrothermal treatment of the kaolin previously calcined at 500 to 800 ° C with aqueous alkali hydroxide is carried out at 50 to 100 ° C. The crystallization reaction taking place is generally complete after 0.5-3 hours.

Marketed, slurried kaolins mainly consist of the clay mineral kaolinite with the approximate composition AI203 2 Si02. 2 H ₂ 0, which has a layer structure. In order to obtain the alkali aluminum silicates to be used according to the invention by hydrothermal treatment with alkali metal hydroxide, the kaolin must first be destroyed, which is most conveniently carried out by heating the kaolin to temperatures of 500 to 800 ° C. for two to four hours. The x-ray-amorphous water-free metakaolin is formed from the kaolin. In addition to calcining, the kaolin can also be destroyed by mechanical treatment (grinding) or by acid treatment.

The kaolins that can be used as starting material are light powders of great purity; however, their iron content is around 2000 to 10000 ppm. Fe significantly higher than the values from 20 to 100 ppm. Fe in the case of the alkali aluminum silicates produced by precipitation from alkali silicate and alkali aluminate solutions. This higher iron content in the alkali aluminum silicates made from kaolin is not a disadvantage, since the iron in the form of iron oxide is firmly built into the alkali aluminum silicate lattice and is not dissolved out. The hydrothermal exposure of sodium hydroxide to destructured kaolin creates a sodium aluminum silicate with a cubic, faujasite-like structure.

Alkali aluminum silicates which can be used according to the invention can also be prepared from calcined (destructured) kaolin by hydrothermal treatment with aqueous alkali hydroxide with the addition of silicon dioxide or a compound which provides silicon dioxide. The generally obtained mixture of alkali aluminum silicates of different crystal structure consists of very finely divided crystal particles which have a diameter of less than 20 μm and are usually composed 100% of particles smaller than 10 μm. In practice, this conversion of the destructured kaolin is preferably carried out using sodium hydroxide solution and water glass. This creates a sodium aluminum sili kat J, which has several names in the literature, e.g. B. is referred to as molecular sieve 13 X or zeolite NaX (cf. O. Grubner, P. Jiru and M. Rälek, "Molecular Sieves", Berlin 1968, pp. 32, 85-89) when considering the approach to hydrothermal treatment preferably does not stir, possibly introduces low shear energies, and remains at a temperature preferably 10-20 ° C below the boiling temperature (approx. 103 ° C). The sodium aluminum silicate J has a cubic crystal structure similar to the naturally occurring faujasite. The conversion reaction can be influenced in particular by stirring the batch, by elevated temperature (boiling heat at atmospheric pressure or in an autoclave) and higher amounts of silicate, ie by a molar batch ratio Si0 ₂ : Na ₂ 0 of at least 1, in particular 1.0-1.45 be that in addition to or instead of sodium aluminum silicate J, the sodium aluminum silicate F is formed. The sodium aluminum silicate F is referred to in the literature as “zeolite P” or “type B” (cf. DW Breck, “Zeolite Molecular Sieves”, New York 1974, p. 72). The sodium aluminum silicate F has a structure similar to the naturally occurring zeolites Gismondin and Garronit and is in the form of crystallites that appear to be spherical on the outside. In general, the production conditions for sodium aluminum silicate F and for mixtures of J and F are less critical than those for a pure crystal type A.

The types of various alkali aluminum silicates described above can be produced without difficulty in addition to the finely divided form with particle sizes of 0.1-25 μm and also in coarser form with particle sizes of more than 25 μm to 5 mm. This can either be done by omitting the measures that prevent crystal growth or agglomerate formation, or by subsequently converting finely divided products into a granular form in a known manner. The desired particle size can then be adjusted if necessary by grinding and air separation.

Also suitable for the use according to the invention in leather production in combination with carboxylic acids containing ester and / or urethane and / or amide groups are aluminum silicates in which, in the aforementioned formula, Kat is an alkali metal ion and / or a divalent and / or trivalent cation , where Kat consists of at least 20 mol% of alkali metal ions, preferably sodium ions, x a number from 0.7 to 1.5, n a number from 1 to 3, y a number from 0.8 to 6, preferably 1.3 - 4 mean, with a particle size of 0.1 µ to 5 mm and a calcium binding capacity of 20-200 mg CaO / g of anhydrous active substance. In order to prepare aluminum silicates containing divalent or trivalent cations, it is possible in some cases to carry out the reactions mentioned above for the preparation of the alkali aluminum silicates with those aluminates or silicates which already contain corresponding cations in salt form. In general, corresponding aluminum silicates are obtained by ion exchange from alkali aluminum silicates with polyvalent cations, e.g. Calcium, magnesium, zinc or aluminum ions obtained in a known manner.

• 0,8 CaO . 0,2 Na₂O . Al₂O₃ 2 Si02
• 0,4 CaO . 0,5 Na₂O. Al₂O₃ Si02,
• 0,18 MgO . 0,77 Na₂O . Al₂O₃ . 1,9 Si0₂,
• 0,16 MgO . 0,8 Na₂O . Al₂O₃ 2,05 Si0₂,
• 0,11 ZnO . 0,92 Na₂O . Al₂O₃ 2 SiO₂.

Examples of aluminum silicates in which the alkali cations are partially replaced by polyvalent cations, in particular calcium, magnesium or zinc ions, can be given by the following formulas:

• 0.8 CaO. 0.2 Na ₂ O. Al ₂ O ₃ 2 SiO 2
• 0.4 CaO. 0.5 Na ₂ O. Al ₂ O ₃ SiO 2,
• 0.18 MgO. 0.77 Na ₂ O. Al ₂ O ₃ . 1.9 Si0 ₂ ,
• 0.16 MgO. 0.8 Na ₂ O. Al ₂ O ₃ 2.05 Si0 ₂ ,
• 0.11 ZnO. 0.92 Na ₂ O. Al ₂ O ₃ 2 SiO ₂ .

The products contain about 8-27% by weight of water. They can be used in crystalline and amorphous form.

Further aluminum silicates suitable for the use according to the invention are those in which, in the above-mentioned formula, Kat is an alkali metal ion and / or a divalent and / or a trivalent cation, x is a number from 0.5 to 1.8, y is a number from 0, 8-6, preferably 1.3-4, mean with a particle size of 0.1 µ to 5 mm and a calcium binding capacity of 0 to <20 mg CaO / g of anhydrous active substance.

• 1,05 Na₂O . Al₂O₃ 3,8 Si0₂
• Ca-Bindevermögen O mg CaO/g,
• 1,0 Na₂O . Al₂O₃. 2,1 Si0₂
• Ca-Bindevermögen 16 mg CaO/g,
• 0,05 Na₂O . 0,94 CaO . Al₂O₃. 1,92 Si02
• Ca-Bindevermögen <15 mg CaO/g,
• 0,09 Na₂O. 0,82 MgO . Al₂O₃. 2,38 Si0₂
• Ca-Bindevermögen <15 mg CaO/g.

The aluminum silicates in this group include amorphous, crystalline, synthetic and natural products. They can be prepared synthetically in a simple manner, for example by reacting water-soluble silicates with water-soluble aluminates in the presence of water, as has already been described in principle in the above production processes. The following aluminum silicates can be cited as examples of such products:

• 1.05 Na ₂ O. Al ₂ O ₃ 3.8 Si0 ₂
• Ca binding capacity O mg CaO / g,
• 1.0 Na ₂ O. Al ₂ O ₃ . 2.1 Si0 ₂
• Ca binding capacity 16 mg CaO / g,
• 0.05 Na ₂ O. 0.94 CaO. Al ₂ O ₃ . 1.92 Si02
• Ca binding capacity <15 mg CaO / g,
• 0.09 Na ₂ O. 0.82 MgO. Al ₂ O ₃ . 2.38 Si0 ₂
• Ca binding capacity <15 mg CaO / g.

Aluminum silicates can also be used for the use according to the invention in leather production, in which, in the abovementioned formula, Kat has an alkali metal ion and / or a divalent and / or trivalent cation, x a number from 0.5 to 1.8, y a number> 6 to 50, preferably> 6 to 20, with a particle size of 0.1 μ to 5 mm and a calcium binding capacity of 0-200 mg CaO / g of anhydrous active substance.

• 1,3 Na20 Al₂O₃ 13,4 SiO₂
• 0,6 Na₂O . Al₂O₃ 8,3 Si0₂
• 1,1 Na₂O · Al₂O₃. 14,8 SiO₂
• ₁,₅ Na₂O . A1203 12,2 Si0₂
• 1,5 Na₂O . Al₂O₃. 11,8 Si0₂.

Such aluminum silicates can be amorphous or crystalline and of synthetic or natural origin. They can be prepared synthetically in a simple manner, for example by reacting water-soluble silicates with water-soluble aluminates in the presence of water. For this purpose, aqueous solutions of the starting materials mixed together or a component present in the solid state can be reacted with the other component present as an aqueous solution. Polyvalent cations can be introduced by processes known from the literature by exchanging monovalent cations, for example sodium ions, for divalent and trivalent cations such as calcium, magnesium, zinc or aluminum ions. In addition to the cations mentioned, the natural aluminum silicates can also contain other cations in a fluctuating, usually small amount. These include, for example, lithium, potassium, thallium, manganese, cobalt, nickel ions. Quaternary nitrogen compounds, such as, for example, ammonium ions, can also be present in varying amounts as cations in synthetic aluminum silicates. The extent of the loading of the aluminum silicates with the cations mentioned largely depends on the size of the selectivity coefficients. However, those aluminum silicates of the stated general composition are advantageously used in which, in the general formula, Kat represents an alkali metal ion, preferably a sodium ion. Examples of such products can be represented by the following formulas:

• 1.3 Na20 Al ₂ O ₃ 13.4 SiO ₂
• 0.6 Na ₂ O. Al ₂ O ₃ 8.3 Si0 ₂
• 1.1 Na ₂ O.Al ₂ O ₃ . 14.8 SiO ₂
• _{1, 5} Na ₂ O. A1203 12.2 Si0 ₂
• 1.5 Na ₂ O. Al ₂ O ₃ . 11.8 Si0 ₂ .

• Eine Suspension von 2 g Aluminiumsilikat (bezogen auf wasserfreie Aktivsubstanz) in 100 ml destilliertem Wasser wird unter Rühren im Laufe von 8-30 Minuten bei einer Temperatur von 22°C langsam mit 2 ml konzentrierter Ameisensäure versetzt. Bei einem erfindungsgemäss verwendbaren Aluminiumsilikat muss sich nach der Gesamtzugabe der 2 ml Ameisensäure ein pH-Wert der Suspension oberhalb von 2,5, zwischen 2,5 und 5,5, vorzugsweise zwischen 3,5 und 4,5 ergeben. Werden diese pH-Werte bei der Titration erreicht, so liegt ein Aluminiumsilikat vor, das im Hinblick auf sein Säurebindungsvermögen für den erfindungsgemässen Einsatz geeignet ist. Produkte, bei denen nach dieser Methode ein pH-Wert ausserhalb dieses Bereichs gefunden wird, besitzen entweder ein zu niedriges Säurebindevermögen oder eine zu hohe Alkalität und sind im erfindungsgemässen Sinne nicht verwendbar. Für reine Neutralisationszwecke, die nicht Gegenstand vorliegender Erfindung sind, können auch stärker alkalische Aluminiumsilikate zum Einsatz gelangen.

An essential criterion for the usability according to the invention of all of the above-mentioned aluminum silicates is their at least partial acid solubility in the pH range from 2.5 to 5, preferably 3.5 to 4.5. The products that meet this requirement are at least partially dissolved by a solution of 2.5 ml of concentrated formic acid in 100 ml of water. This acid solubility test is carried out in the following way:

• A suspension of 2 g of aluminum silicate (based on anhydrous active substance) in 100 ml of distilled water is slowly mixed with 2 ml of concentrated formic acid over a period of 8-30 minutes at a temperature of 22 ° C. In the case of an aluminum silicate which can be used according to the invention, after the total addition of the 2 ml of formic acid, the pH of the suspension must be above 2.5, between 2.5 and 5.5, preferably between 3.5 and 4.5. If these pH values are reached during the titration, then an aluminum silicate is present which is suitable for the use according to the invention with regard to its acid-binding capacity. Products in which a pH value outside this range is found using this method either have an acid binding capacity which is too low or an alkalinity which is too high and cannot be used in the sense according to the invention. For pure neutralization purposes, which are not the subject of the present invention, more alkaline aluminum silicates can also be used.

• 1 1 einer wässrigen, 0,594 g CaCI₂ (= 300 mg CaO/1 = 30°dH) enthaltenden und mit verdünnter NaOH auf einen pH-Wert von 10 eingestellten Lösung wird mit 1 g Aluminiumsilikat, berechnet als wasserfreies Produkt, versetzt. Dann wird die Suspension 15 Minuten lang bei einer Temperatur von 22°C kräftig gerührt. Nach Abfiltrieren des Aluminiumsilikates bestimmt man die Resthärte x des Filtrates. Daraus errechnet sich das Calciumbindevermögen in mg CaO/g Aluminiumsilikat nach der Formel: (30-x). 10.

The Ca binding capacity can be determined in the following way:

• 1 g of an aqueous solution containing 0.594 g of CaCl ₂ (= 300 mg of CaO / 1 = 30 ° dH) and adjusted to pH 10 with dilute NaOH is mixed with 1 g of aluminum silicate, calculated as an anhydrous product. Then the suspension is stirred vigorously for 15 minutes at a temperature of 22 ° C. After filtering off the aluminum silicate, the residual hardness x of the filtrate is determined. The calcium binding capacity in mg CaO / g aluminum silicate is calculated from the formula: (30-x). 10th

The tanning of fur skins and leather is carried out in the usual way. Pimples and tanning can be combined in a known manner. The leather can then be greased. For chrome tanning, about 1 to 50 g / 1, preferably 15-30 g / l, of aluminum silicate, based on the anhydrous product, are used in the tanning liquor. The ester and / or urethane and / or amide group-containing carboxylic acids are used in the tanning liquor in an amount of 1 to 20 g / l. Reaction products from adipic acid and dipropylene glycol (COOH: OH = 2 1) or reaction products from adipic acid and trimethylolpropane (COOH: OH = 5: 3) are preferred. The addition can also take place in the pimple, the amount is then also about 1 to 20 g / l of liquor. In addition, the usual active ingredients and auxiliary substances, e.g. anionic, cationic or nonionic surfactants, chromium salts etc. are used. In particular, dicarboxylic acids, such as adipic acid or glutaric acid or their monomethyl esters, are additionally used in amounts of 1 to 20 g / l of liquor.

In the process according to the invention, the concentration of the chromium salts in the tanning liquor can be reduced by 25-50% compared to the normal tanning processes.

Manufacture of aluminum silicates

The silicate solution was added to the aluminate solution with vigorous stirring in a 15 liter container. Was stirred with a stirrer with a dispersing disc at 3000 revolutions / min. Both solutions were at room temperature. An X-ray amorphous sodium aluminum silicate formed as the primary precipitation product under an exothermic reaction. After stirring for 10 minutes, the suspension of the precipitate was transferred to a crystallization container, where it remained for 6 hours at 90 ° C. with stirring (250 revolutions / min.) For the purpose of crystallization. After the lye had been suctioned off from the crystal slurry and rinsed with deionized water until the wash water running off had a pH of approximately 10, the filter residue was dried.

The water contents were determined by heating the pre-dried products at 800 ° C for one hour. Washed up to a pH of approx. 10 Beautiful or neutralized and then dry sodium aluminum silicates were then ground in a ball mill. The grain size distribution was determined using a sedimentation balance.

Production conditions for sodium aluminum silicate A: Precipitation:

• 17,7% Na₂O,15,8% AI₂O₃, 66,6% H₂0,
• 0,15 kg Ätznatron,
• 9,420 kg Wasser,
• 2,445 kg einer aus handelsüblichem Wasserglas und leicht alkalilöslicher Kieselsäure frisch hergestellten, 25,8 %igen Natriumsilikatlösung der Zusammensetzung 1 Na₂O 6,0 Si0₂.

2.985 kg of aluminate solution of the composition:

• 17.7% Na ₂ O, 15.8% Al ₂ O ₃ , 66.6% H ₂ 0,
• 0.15 kg caustic soda,
• 9.420 kg water,
• 2.445 kg of a 25.8% strength sodium silicate solution of the composition 1 Na ₂ O 6.0 SiO ₂ freshly prepared from commercially available water glass and slightly alkali-soluble silica.

Crystallization:

6 hours at 90 ° C.

Drying:

24 hours at 100 ° C.

Composition:

0.9 Na ₂ O. 1 Al ₂ O ₃ . 2.04 SiO ₂ . 4.3 H ₂ 0 (= 21.6% H ₂ 0).

Degree of crystallization:

fully crystalline,

Calcium binding capacity:

170 mg CaO / g active substance.

In the particle size distribution determined by sedimentation analysis, the maximum particle size was found to be 2-6 6µ.

Production conditions for sodium aluminum silicate B:

Precipitation:

7.63 kg of an aluminate solution of the composition 13.2% Na ₂ 0; 8.0% Al ₂ O ₃ ; 78.8% H ₂ O; 2.37 kg of a sodium silicate solution of the composition 8.0% Na ₂ 0; 26.9% SiO ₂ ; 65.1% H ₂ O;

Mixing ratio:

3.24 Na ₂ 0; 1.0 Al ₂ O ₃ ; 1.78 Si0 ₂ ; 70.3 H ₂ 0;

Crystallization:

6 hours at 90 ° C;

Drying:

24 hours at 100 ° C;

Composition of the dried product: 0.99 Na ₂ O. 1.00 AI ₂ 0 ₃ . 1.83 Si0 ₂ . 4.0 H ₂ O; (= 20.9% H ₂ O);

Crystal shape:

• mittlerer Partikeldurchmesser: 5,4 µ;

cubic with very rounded corners and edges:

• average particle diameter: 5.4 µ;

Calcium binding capacity:

172 mg CaO / g active substance.

• Fällung:
  • 12,15 kg einer Aluminatlösung der Zusammensetzung 14,5% Na₂O; 5,4%AI₂0₃; 80,1% H₂O;
  • 2,87 kg einer Natriumsilikatlösung der Zusammensetzung 8,0% Na₂O; 26,9% SiO₂; 65,1% H₂O;
• Ansatzverhältnis in Mol:
  • 5,0 Na₂0; 1,0 Al₂O₃; 2,0 Si0₂; 100 H₂0;
• Kristallisation:
  • 1 Stunde bei 90°C;
• Trocknung:
  • Heisszerstäubung einer Suspension des gewaschenen Produktes (pH 10) bei 295°C; Feststoffgehalt der Suspension 46%;
  • Zusammensetzung des getrockneten Produktes: 0,96 Na₂O . 1 Al₂O₃ . 1,96 Si0₂. 4 H₂0;
• Kristallform:
  • kubisch mit stark abgerundeten Ecken und Kanten; Wassergehalt 20,5%
• mittlerer Partikeldurchmesser:
  • 5,4 µ.
• Calciumbindevermögen:
  • 172 mg CaO/g Aktivsubstanz.
• Herstellungsbedingungen für das Kaliumaluminiumsilikat D:
  • Es wurde zunächst das Natriumaluminiumsilikat C hergestellt. Nach Absaugen der Mutterlauge und Waschen der Kristallmasse mit entmineralisiertem Wasser bis zum pH-Wert 10 wurde der Filterrückstand in 6,1 l einer 25%igen KCI-Lösung aufgeschlämmt. Die Suspension wurde kurzzeitig auf 80 - 90°C erhitzt; dann wurde abgekühlt und wider abfiltriert und gewaschen.
• Trocknung:
  • 24 Stunden bei 100 °C;
  • Zusammensetzung des getrockneten Produktes: 0,35 Na₂0 . 0,66 K₂0 . 1,0 Al₂O₃ . 1,96 SiO₂ . 4,3 H₂0; (Wassergehalt 20,3%).

Production conditions for sodium aluminum silicate C:

• Precipitation:
  • 12.15 kg of an aluminate solution of the composition 14.5% Na ₂ O; 5.4% Al ₂ 0 ₃ ; 80.1% H ₂ O;
  • 2.87 kg of a sodium silicate solution of the composition 8.0% Na ₂ O; 26.9% SiO ₂ ; 65.1% H ₂ O;
• Mixing ratio:
  • 5.0 Na ₂ 0; 1.0 Al ₂ O ₃ ; 2.0 Si0 ₂ ; 100 H ₂ 0;
• Crystallization:
  • 1 hour at 90 ° C;
• Drying:
  • Hot atomization of a suspension of the washed product (pH 10) at 295 ° C; Solids content of the suspension 46%;
  • Composition of the dried product: 0.96 Na ₂ O. 1 Al ₂ O ₃ . 1.96 Si0 ₂ . 4 H ₂ 0;
• Crystal shape:
  • cubic with very rounded corners and edges; Water content 20.5%
• average particle diameter:
  • 5.4 µ.
• Calcium binding capacity:
  • 172 mg CaO / g active substance.
• Production conditions for the potassium aluminum silicate D:
  • The sodium aluminum silicate C was first produced. After sucking off the mother liquor and washing the crystal mass with demineralized water up to pH 10, the filter residue was suspended in 6.1 l of a 25% KCI solution. The suspension was briefly heated to 80-90 ° C; then it was cooled and again filtered off and washed.
• Drying:
  • 24 hours at 100 ° C;
  • Composition of the dried product: 0.35 Na ₂ 0. 0.66 K ₂ 0. 1.0 Al ₂ O ₃ . 1.96 SiO ₂ . 4.3 H ₂ 0; (Water content 20.3%).

• Fällung:
  • 0,76 kg Aluminatlösung der Zusammensetzung: 36,0% Na₂0, 59,0% Al₂O₃, 5,0% Wasser; 0,94 kg Ätznatron; 9,49 kg Wasser; 3,94 kg einer handelsüblichen Natriumsilikatlösung der Zusammensetzung:
    • 8,0% Na₂0, 26,9% SiO₂, 65,1% H₂0;
• Kristallisation:
  • 12 Stunden bei 90°C;
• Trocknung:
  • 12 Stunden bei 100°C;
• Zusammensetzung:
  • 0,9 Na₂O . 1 Al₂O₃. 3,1 SiO₂ . 5 H₂0;
• Kristallisationsgrad:
  • voll kristallin.

Production conditions for the sodium aluminum silicate E:

• Precipitation:
  • 0.76 kg aluminate solution of the composition: 36.0% Na ₂ 0, 59.0% Al ₂ O ₃ , 5.0% water; 0.94 kg caustic soda; 9.49 kg water; 3.94 kg of a commercially available sodium silicate solution of the set tongue:
    • 8.0% Na ₂ 0, 26.9% SiO ₂ , 65.1% H ₂ 0;
• Crystallization:
  • 12 hours at 90 ° C;
• Drying:
  • 12 hours at 100 ° C;
• Composition:
  • 0.9 Na ₂ O. 1 Al ₂ O ₃ . 3.1 SiO ₂ . 5 H ₂ 0;
• Degree of crystallization:
  • fully crystalline.

The maximum particle size was 3-6 µ.

• 110 mg CaO/g Aktivsubstanz.

Calcium binding capacity:

• 110 mg CaO / g active substance.

• Fällung:
  • 10,0 kg einer Aluminatlösung der Zusammensetzung: 0,84 kg NaAlO₂ + 0,17 kg NaOH + 1,83 kg H₂O;
  • 7,16 kg einer Natriumsilikatlösung der Zusammensetzung: 8,0% Na₂0, 26,9% SiO₂, 65,1% H₂O;
• Kristallisation:
  • 4Stunden bei 150°C;
• Trocknung:
  • Heisszerstäubung einer 30%igen Suspension des gewaschenen Produktes (pH 10);
  • Zusammensetzung des getrockneten Produktes: 0,98 Na₂0 . 1 Al₂O₃. 4,12 SiO₂ . 4,9 H₂0;
  • Die Partikel besitzen Kugelgestalt; der Kugeldurchmesser beträgt im Durchschnitt etwa 3-6 µ.
• Calciumbindevermögen:
  • 132 mg CaO/g Aktivsubstanz bei 50°C.

Production conditions for sodium aluminum silicate F:

• Precipitation:
  • 10.0 kg of an aluminate solution of the composition: 0.84 kg NaAlO ₂ + 0.17 kg NaOH + 1.83 kg H ₂ O;
  • 7.16 kg of a sodium silicate solution of the composition: 8.0% Na ₂ 0, 26.9% SiO ₂ , 65.1% H ₂ O;
• Crystallization:
  • 4 hours at 150 ° C;
• Drying:
  • Hot atomization of a 30% suspension of the washed product (pH 10);
  • Composition of the dried product: 0.98 Na ₂ 0. 1 Al ₂ O ₃ . 4.12 SiO ₂ . 4.9 H ₂ 0;
  • The particles are spherical in shape; the ball diameter averages around 3-6 µ.
• Calcium binding capacity:
  • 132 mg CaO / g active substance at 50 ° C.

• Fällung:
  • 7,31 kg Aluminat (14,8% Na₂0, 9,2% Al₂O₃, 76,0% H₂0);
  • 2,69 kg Silikat (8,0% Na₂0, 26,9% Si0₂, 65,1% H₂0);
• Ansatzverhältnis in Mol:
  • 3,17 Na₂O,1,0 Al₂O₃,1,82 SiO₂, 62,5 H₂0;
• Kristallisation:
  • 6 Stunden bei 90°C;
  • Zusammensetzung des getrockneten Produktes: 1,11 Na₂0 . 1 Al₂O₃ . 1,89 SiO₂ . 3,1 H₂0 (= 16,4% H₂0);
  • Kristallstruktur:
  • Strukturelle Mischtype im Verhältnis 1 : 1;
• Kristallform:
  • abgerundete Kristallite;
• Mittlerer Partikeldurchmesser:
  • 5,6 µ.
• Calciumbindevermögen:
  • 105 mg CaO/g Aktivsubstanz bei 50°C.

Production conditions for the sodium aluminum silicate G:

• Precipitation:
  • 7.31 kg of aluminate (14.8% Na ₂ 0, 9.2% Al ₂ O ₃ , 76.0% H ₂ 0);
  • 2.69 kg of silicate (8.0% Na ₂ 0, 26.9% Si0 ₂ , 65.1% H ₂ 0);
• Mixing ratio:
  • 3.17 Na ₂ O, 1.0 Al ₂ O ₃ , 1.82 SiO ₂ , 62.5 H ₂ 0;
• Crystallization:
  • 6 hours at 90 ° C;
  • Composition of the dried product: 1.11 Na ₂ 0. 1 Al ₂ O ₃ . 1.89 SiO ₂ . 3.1 H ₂ 0 (= 16.4% H ₂ 0);
  • Crystal structure:
  • Structural mixed types in a ratio of 1: 1;
• Crystal shape:
  • rounded crystallites;
• Average particle diameter:
  • 5.6 µ.
• Calcium binding capacity:
  • 105 mg CaO / g active substance at 50 ° C.

Production conditions for sodium aluminum silicate H made from kaolin:

1. Destruction of kaolin

To activate the natural kaolin, samples of 1 kg were heated to 700 ° C in a fireclay crucible for 3 hours. The crystalline kaolin AI ₂ 0 _{3 changed} . 2 Si0 ₂ . 2 H ₂ 0 in the amorphous metakaolin Al ₂ O ₃ . 2 SiO ₂ µm.

2. Hydrothermal treatment of metakaolin

• Ansatz:
  • 1,65 kg calcinierter Kaolin; 13,35 kg NaOH 10%ig, Vermischen bei Raumtemperatur;
• Kristallisation:
  • 2 Stunden bei 100°C;
• Trocknung:
  • 2 Stunden bei 160°C im Vakuumtrockenschrank;
• Zusammensetzung:
  • 0,88 Na₂0 . 1 Al₂O₃ . 2,14 SiO₂ . 3,5 H₂0 (= 18,1%H₂O);
• Kristallstruktur:
  • Strukturelle Mischtype wie Na-Aluminiumsilikat G, jedoch Verhältnis 8: 2.
• Mittlerer Teilchendurchmesser: 7,0 µ.
• Calciumbindevermögen:
  • 126 mg CaO/g Aktivsubstanz.

Alkali lye was placed in a stirred vessel and the calcined kaolin was stirred in at temperatures between 20 and 100.degree. The suspension was brought to the crystallization temperature of 70 to 100 ° C. with stirring and kept at this temperature until the crystallization process was complete. The mother liquor was then suctioned off and the residue was washed with water until the wash water running off had a pH of 9 to 11. The filter cake was dried and then crushed to a fine powder, or it was ground to remove the agglomerates formed during drying. This grinding process was omitted if the filter residue was processed wet or if the drying was carried out using a spray dryer or a current dryer. The hydrothermal treatment of the calcined kaolin can also be carried out according to a continuous procedure.

• Approach:
  • 1.65 kg calcined kaolin; 13.35 kg NaOH 10%, mixing at room temperature;
• Crystallization:
  • 2 hours at 100 ° C;
• Drying:
  • 2 hours at 160 ° C in a vacuum drying cabinet;
• Composition:
  • 0.88 Na ₂ 0. 1 Al ₂ O ₃ . 2.14 SiO ₂ . 3.5 H ₂ 0 (= 18.1% H ₂ O);
• Crystal structure:
  • Structural mixed types like Na aluminum silicate G, however ratio 8: 2.
• Average particle diameter: 7.0 µ.
• Calcium binding capacity:
  • 126 mg CaO / g active substance.

• Die Destrukturierung des Kaolins und die hydrothermale Behandlung erfolgte in analoger Weise wie bei H angegeben.

Production conditions for sodium aluminum silicate made from kaolin:

• The destructuring of the kaolin and the hydrothermal treatment was carried out in an analogous manner to that given for H.

• Approach:
  • 2.6 kg calcined kaolin,
  • 7.5 kg NaOH 50%, 7.5 kg water glass,
  • 51.5 kg of deionized water, mixing at room temperature;
• Crystallization:
  • 24 hours at 100 ° C, without stirring;
• Drying:
  • 2 hours at 160 ° C in a vacuum drying cabinet;
• Composition:
  • 0.93 Na ₂ O. 1 Al ₂ O ₃ . 3.60 SiO ₂ . 6.8 H ₂ 0 (= 24.6% H ₂ 0);
• Crystal structure:
  • Sodium aluminum silicate J as defined above, cubic crystallites;
  • Average particle diameter: 8.0 µ.
• Calcium binding capacity:
  • 105 mgCaO / g active substance.

• 50 kg des pulverförmigen kristallinen getrockneten Alkalialuminiumsilikats A wurden in einem 300-I-Rührbehälter mit 180 I Wasser aufgeschlämmt und mit 25%iger Salzsäure auf einen pH-Wert von 6 eingestellt. Diese Suspension wurde 40 Minuten lang mässig stark gerührt. Dann trennte man das Alumosilikat auf einem Vakuumfilter ab und wusch den Filterkuchen 3 x mit je 20 1 Wasser aus. Das Alumosilikat wurde in einem Trockenschrank bei 105°C 10 Stunden lang getrocknet.

Production of the sodium aluminum silicate K in granular form:

• 50 kg of the powdery, crystalline, dried alkali aluminum silicate A were slurried in a 300 l stirred tank with 180 l water and adjusted to a pH of 6 using 25% hydrochloric acid. This suspension was moderately stirred for 40 minutes. Then the aluminosilicate was separated off on a vacuum filter and the filter cake was washed 3 times with 20 l of water each time. The aluminosilicate was dried in a drying cabinet at 105 ° C for 10 hours.

This thus dried aluminosilicate was mixed with 10 kg bentonite and 20.1 kg water, which had been adjusted to pH 6 with 25% hydrochloric acid, and in a 100 kg "Lödige" mixer (paddle mixer from Lödige) for 20 minutes. With further mixing, the granulate formation was brought about within a further 8 minutes by the gradual addition of 13.5 kg of further water, likewise adjusted to a pH of 6.

The granules were dried in a drying cabinet at 150 ° C. for 60 minutes and solidified by subsequent heating (15 minutes at 780 ° C.).

To determine the exchange capacity, 1 g of granules was boiled in 500 ml of drinking water at 16 ° dH for 5 minutes. The residual hardness was then determined by titrimetry in a filtered sample of the treated water after cooling.

The calcium binding capacity of the product was 120 mg CaO / g active substance. The grain size was 0.08 to 2 mm. When using an Eirich turbo mixer (plate / turbo mixer from Eirich) the required homogenization and granulation times were shorter. If one proceeded as described above for the production of the sodium aluminum silicate A in the form of granules, the homogenization and the formation of the granules was completed after a total of 5 minutes (instead of after 28 minutes with the paddle mixer). After drying for 15 minutes at 100 ° C. and calcining for 5 minutes at 800 ° C. in a forced air muffle furnace, granules were obtained which had good exchangeability, good hot water resistance and grain strength.

The calcium binding capacity of the product was 110 mg CaO / g active substance. The grain size was 0.08 to 2 mm.

In a corresponding manner, other granules of alkali aluminum silicates with particle sizes of more than 25 μ to 5 mm can be produced if alkali aluminum silicates of types B-J of the main patent are treated in accordance with the above manufacturing instructions.

Production of the aluminum silicate L:

• Zusammensetzung:
  • 0,28 Na₂0 . 0,7 CaO . Al₂O₃ . 1,95 SiO₂ . 4 H₂0
• Ca-Bindevermögen:
  • >20 mg CaO/g Aktivsubstanz.
• Teilchengrösse:
  • mittlerer Teilchendurchmesser 5,8 g.
• Kristallform:
  • A-Type, kristallin.

A product of the composition 0.98 Na ₂ 0 produced in accordance with the specifications for alkali aluminum silicate C. Al ₂ O ₃ . 1.96 SiO ₂ . 4.2 H ₂ 0 was slurried in a solution containing calcium chloride. Sodium was exchanged for calcium under an exothermic reaction. After a reaction time of 15 minutes, the mixture was filtered off and washed. Drying was carried out by hot atomization of a 40% suspension at an atomization temperature of 198-250 ° C. The product obtained had the following characteristics:

• Composition:
  • 0.28 Na ₂ 0. 0.7 CaO. Al ₂ O ₃ . 1.95 SiO ₂ . 4 H ₂ 0
• Ca binding capacity:
  • > 20 mg CaO / g active substance.
• Particle size:
  • average particle diameter 5.8 g.
• Crystal shape:
  • A-type, crystalline.

Production of aluminum silicate M:

• Zusammensetzung:
  • 0,42 Na₂O . 0,47 MgO . Al₂O₃. 2,61 SiO₂. 5,6 H₂0.
• Ca-Bindevermögen:
  • >25 mg CaO/g Aktivsubstanz
• Teilchengrösse:
  • mittlerer Teilchendurchmeser 10,5 µ.

Alumosilicate with the composition 0.89 Na ₂ 0. AI ₂ 0 ₃ . 2.65 Si0 ₂ . 6 H ₂ 0 was slurried in a solution containing magnesium chloride. After a reaction time of 30 minutes at 80-90 ° C., the mixture was filtered off and washed. The drying was carried out as tray drying for 16 hours at 100 ° C. The product obtained had the following key figures:

• Composition:
  • 0.42 Na ₂ O. 0.47 MgO. Al ₂ O ₃ . 2.61 SiO ₂ . 5.6 H ₂ 0.
• Ca binding capacity:
  • > 25 mg CaO / g active substance
• Particle size:
  • average particle diameter 10.5 µ.

Production of aluminum silicate N:

• Zusammensetzung:
  • 0,92 Na₂O . 0,11 ZnO . Al₂O₃ . 1,98 SiO₂ . 6 H₂O.
• Ca-Bindevermögen:
  • 76 mg CaO/g Aktivsubstanz.
• Teilchengrösse:
  • mittlerer Teilchendurchmesser 36 µ.

An X-ray amorphous aluminosilicate with the composition 1.03 Na ₂ O. AI ₂ 0 ₃ . 2.14 SiO ₂ . 5.8 H ₂ O was treated in the manner described for aluminosilicate M in a solution containing zinc sulfate, then washed and dried under mild conditions. The product obtained had the following characteristics:

• Composition:
  • 0.92 Na ₂ O. 0.11 ZnO. Al ₂ O ₃ . 1.98 SiO ₂ . 6 H ₂ O.
• Ca binding capacity:
  • 76 mg CaO / g active substance.
• Particle size:
  • average particle diameter 36 µ.

Production of aluminum silicate O:

50 kg of the aluminosilicate L were slurried in a 300 l stirred tank with 180 l water and adjusted to a pH of 6 using 25% hydrochloric acid. The suspension was stirred moderately vigorously for 40 minutes. The aluminosilicate was then filtered off, washed out several times with water and dried at 105 ° C. for 10 hours. The dried aluminosilicate was mixed with 10 kg of bentonite and 20 l of water, which had been adjusted to a pH of 6 with 25% hydrochloric acid, and homogenized in a 100 kg paddle mixer for 20 minutes. The granules were formed within a further 8 minutes with stirring by gradually adding 13.5 l of water adjusted to a pH of 6. The granulate was dried at 150 ° C. for 60 minutes and solidified by heating to 780 ° C. for 15 minutes. The grain size distribution of the aluminosilicate 0 obtained in this way was 1 to 2 mm.

Production of aluminum silicate P:

• Zusammensetzung:
  • 0,6 Na₂O . 0,24 MgO . 0,83 Al₂O₃ . 2,0 SiO₂ . 4,8 H₂0 und 7% Hexadecyltrimethylammoniumchloride.
• Ca-Bindevermögen:
  • 84 mg CaO/g Aktivsubstanz
• Teilchengrösse:
  • mittlerer Teilchendurchmesser 16 µ (nach Mahlung).

80 g of a 15% strength solution of hexadecyltrimethylammonium chloride and 140 g of a 35% strength sodium silicate (Na ₂ O: SiO ₂ = 1: 3.4), dissolved in 550 ml of deionized water, were placed in a vessel of 1.5 l content . With vigorous mixing, 46 g of sodium aluminate (38% Na ₂ 0, 52% Al ₂ 0 ₃ ) were dissolved in 150 ml of water and immediately 43.9 g of MgSO ₄ . 7 H ₂ 0, dissolved in 100 g of water, added. After stirring for 3 hours, the product formed was filtered off, washed with water and the filter residue was dried at 100 torr and 80 ° C. for 35 hours. The product obtained had the following characteristics:

• Composition:
  • 0.6 Na ₂ O. 0.24 MgO. 0.83 Al ₂ O ₃ . 2.0 SiO ₂ . 4.8 H ₂ 0 and 7% hexadecyltrimethylammoniumchloride.
• Ca binding capacity:
  • 84 mg CaO / g active substance
• Particle size:
  • average particle diameter 16 µ (after grinding).

Production of aluminum silicate Q:

• Zusammensetzung:
  • 0,59 Na₂0 . 1,1 Al₂O₃. 1,98 SiO₂. 4,9 H₂O.
• Ca-Bindevermögen:
  • 56 mg CaO/g Aktivsubstanz.
• Teilchengrösse:
  • mittlererTeilchendurchmesser 50 µ.

142.9 g of 35% sodium silicate (Na ₂ 0: Si0 ₂ = 1: 3.4), dissolved in 507.4 g of water, were placed in a vessel of 1.5 l content and mixed with 48.3 g of sodium aluminate ( 38% Na ₂ 0, 52% Al ₂ 0 ₃ ), dissolved in 150 g of water, with stirring. Then 42.4 g of Al ₂ (SO ₄ ) ₃ . 18 H ₂ 0, dissolved in 100 g of water, was added and, after stirring for 10 minutes, 8 g of 50% strength sodium dodecylbenzenesulfonate were added. After stirring for a further 160 minutes, the suspension was processed further as for aluminosilicate P. The product obtained the composition 1.0 Na ₂ O. A _l O ₃ . 2.1 Si0 ₂ . 4.1 H ₂ 0 with 2.1% sodium dodecylbenzenesulfonate, with a Ca binding capacity of 128 mg CaO / g active substance and an average particle diameter of 19 μ was treated with a dilute aluminum sulfate solution at 60 ° C. for 30 minutes. After filtration, washing and subsequent drying at 80 torr and 100 ° C. for 6 hours, the solid was ground. The product obtained had the following characteristics:

• Composition:
  • 0.59 Na ₂ 0. 1.1 Al ₂ O ₃ . 1.98 SiO ₂ . 4.9 H ₂ O.
• Ca binding capacity:
  • 56 mg CaO / g active substance.
• Particle size:
  • average particle diameter 50 µ.

The production of the aluminum silicates, in which, in the above-mentioned formula, Kat is an alkali metal ion and / or a divalent and / or trivalent cation, x is a number from 0.5 to 1.8, the particle size is 0.1 μ to 5 mm and once y is a number from 0.8 to 6 and the calcium binding capacity is 0 to <20 mg CaO / g and on the other hand y is a number from> 6 to 50 and the calcium binding capacity is 0 to 200 mg CaO / g of anhydrous active substance, can in principle be the same Be done as indicated in the manufacturing processes described above. In addition, some of the products are naturally occurring aluminum silicates.

Production of the aluminum silicate R:

• Zusammensetzung:
  • 1,05 Na₂O . Al₂O₃ . 3,8 SiO₂ .
• Ca-Bindevermögen:
  • 0 mg CaO/g Aktivsubstanz.
• MittlererTeilchendurchmesser:
  • 12,3 µ.

An aluminate solution of the composition 0.84 kg NaAlO ₂ , 0.17 kg NaOH, 1.83 kg H ₂ 0 with 7.16 kg of a sodium silicate solution (8.0% Na ₂ 0, 26, 9% Si0 ₂ , 65.1% H ₂ 0) added. Was stirred with a bar stirrer at 300 revolutions / min. Both solutions were at room temperature. An X-ray amorphous sodium aluminum silicate was formed as the primary precipitation product. After stirring for 10 minutes, the suspension of the precipitate was transferred to a crystallization vessel, where it remained for 8 hours at 150 ° C. with vigorous stirring (500 revolutions / min.) For the purpose of crystallization. After the lye had been suctioned off from the crystal slurry and washed with water until the wash water running off had a pH of approximately 11, an approximately 36% suspension of the washed product was dried by hot atomization. The product obtained, which is a synthetic crystalline zeolite (analcite), had the following characteristics:

• Composition:
  • 1.05 Na ₂ O. Al ₂ O ₃ . 3.8 SiO ₂ .
• Ca binding capacity:
  • 0 mg CaO / g active substance.
• Average particle diameter:
  • 12.3 µ.

Production of aluminum silicate S:

• Zusammensetzung:
  • 1 Na₂O . Al₂O₃. 2,1 SiO₂.
• Ca-Bindevermögen:
  • 16 mg CaO/g Aktivsubstanz
• Mittlerer Teilchendurchmesser:
  • 6,1 µ.

The preparation was carried out analogously to the information given for aluminum silicate R, 6.91 kg of aluminate (18.0% Na ₂ O, 11.2% Al ₂ O ₃ , 70.8% H ₂ O ₎ being used for the precipitation. Crystallization of the precipitate was carried out at 100 ° C for 4 hours. After washing out, the filter cake was dried for 24 hours at 100 ° C. and then crushed into a fine powder. The product obtained, a field spatoid hydrosodalite, had the following characteristics:

• Composition:
  • 1 Na ₂ O. Al ₂ O ₃ . 2.1 SiO ₂ .
• Ca binding capacity:
  • 16 mg CaO / g active substance
• Average particle diameter:
  • 6.1 µ.

Production of the aluminum silicate T:

• Zusammensetzung:
  • 0,05 Na₂O . 0,94 CaO . Al₂O₃ 1,92 Si0₂
• Aktivsubstanzgehalt:
  • 79%
• Ca-Bindevermögen:
  • <15 mg CaO/g Aktivsubstanz

To prepare the aluminum silicate containing calcium ions, the 44% slurry of a crystalline sodium aluminum silicate with the composition 1.05 Na ₂ 0. Al ₂ O ₃ . 1.93 Si0 _{2 implemented} with a concentrated calcium chloride solution. After filtering off the approximately 70% calcium-laden product, this process was repeated at 60 ° C. After drying, the product obtained had the following characteristics:

• Composition:
  • 0.05 Na ₂ O. 0.94 CaO. Al ₂ O ₃ 1.92 Si0 ₂
• Active substance content:
  • 79%
• Ca binding capacity:
  • <15 mg CaO / g active substance

Production of aluminum silicate U:

• Zusammensetzung:
  • 0,09 Na₂0 . 0,82 MgO . Al₂O₃ . 2,38 SiO₃
• Aktivsubstanzgehalt:
  • 78%
• Ca-Bindevermögen:
  • <15 mg CaO/g Aktivsubstanz

To prepare the aluminum silicate containing magnesium ions, a 40% slurry of a crystalline sodium aluminum silicate having the composition 0.92 Na ₂ 0. AI ₂ 0 ₃ . 2.39 Si0 ₂ reacted with a concentrated magnesium sulfate solution at 80-90 ° C for 30 minutes. After filtering off the product loaded with magnesium, the treatment was repeated again. The product obtained had the following characteristics after drying:

• Composition:
  • 0.09 Na ₂ 0. 0.82 MgO. Al ₂ O ₃ . 2.38 SiO ₃
• Active substance content:
  • 78%
• Ca binding capacity:
  • <15 mg CaO / g active substance

Production of aluminum silicate V:

• 1,0 Na₂O . Al₂O . 10 SiO₂ . 6,7 H₂O.

This aluminum silicate is a synthetic zeolite (mordenite) in which, according to the aforementioned formula, y has a value> 6. The production of such aluminum silicates is described in more detail in the monograph by Donald W. Breck, Zeolite, Molecular Sieves, published by John Wiley & Sons, NY. The synthetic mordenite is produced from the reaction components sodium aluminate and silica at temperatures between 265 - 295 ° C for 2-3 days and provides a product with the following composition:

• 1.0 Na ₂ O. Al ₂ O. 10 SiO ₂ . 6.7 H ₂ O.

Other aluminum silicates in which y has a value> 6 according to the aforementioned formula are characterized below by commercially available products.

Aluminum silicate W

Commercial amorphous aluminum silicate, type "Zeolex 23 A" from Huber Corp.

• 1,5 Na₂O . Al₂O₃ 12,2 SiO₂.

Composition:

• 1.5 Na ₂ O. Al ₂ O ₃ 12.2 SiO ₂ .

• 82%.

Active substance content:

• 82%.

• 40 mg CaO/g Aktivsubstanz.

Ca binding capacity:

• 40 mg CaO / g active substance.

Aluminum SilicateX

Commercial amorphous aluminum silicate, type “Zeolex 35 P” from Huber Corp.

• 1,5 Na₂O . Al₂O₃.11,8 Si0₂.

Composition:

• 1.5 Na ₂ O. Al ₂ O ₃ .11.8 Si0 ₂ .

• 82%.

Active substance content:

• 82%.

• 46 mg CaO/g Aktivsubstanz.

Ca binding capacity:

• 46 mg CaO / g active substance.

Aluminum silicateY

Commercial amorphous aluminum silicate type "Silteg P 820" from Degussa.

• 1,1 Na20 . AI₂0₃ . 14,8 Si0₂.

Composition:

• 1.1 Na20. AI ₂ 0 ₃ . 14.8 Si0 ₂ .

• 80%.

Active substance content:

• 80%.

• 36 mg CaO/g Aktivsubstanz.

Ca binding capacity:

• 36 mg CaO / g active substance.

Aluminum silicate Z

Natural zeolite. (Clinoptilolite) as it is extracted in large quantities from the open pit in the western United States.

• 0,6 Na₂0 . AI₂0₃ . 8,3 Si0₂.

Composition:

• 0.6 Na ₂ 0. AI ₂ 0 ₃ . 8.3 Si0 ₂ .

• 86%.

Active substance content:

• 86%.

• 0 mg CaO/gAktivsubstanz.

Ca binding capacity:

• 0 mg CaO / g active substance.

Further examples of natural aluminum silicates which can be used according to the invention and in which y has a value> 6 according to the aforementioned formula are the following commercial products from The Anaconda Comp., Denver, USA:

• Type 1010: molares Verhältnis SiO_2/Al₂O_{3 =} 9,8.
• Type 2020: molares Verhältnis SiO_2/Al₂O₃ = 11,4.
• Type 3030: molares Verhältnis Si0_2/A1₂0₃ = 9,0.
• Type 4040: molares Verhältnis Si0_2/AI₂0_{3 =} 7,4.

Anaconda, natural zeolite

• Type 1010: molar ratio SiO _{2 /} Al ₂ O _{3 =} 9.8.
• Type 2020: molar ratio SiO _{2 /} Al ₂ O ₃ = 11.4.
• Type 3030: molar ratio Si0 _{2 /} A1 ₂ 0 ₃ = 9.0.
• Type 4040: molar ratio Si0 _{2 /} Al ₂ 0 _{3 =} 7.4.

The following examples are intended to explain the subject matter of the invention in more detail, but without restricting it thereto.

Examples example 1 Chrome tanning of furniture leather

• Die Blössen werden mit
• 100% Wasser
• 7% Kochsalz
• bei 20°C im Fass 10 Minuten laufen gelassen. Anschliessend erfolgt ein Zusatz von
• 1,0% Umsetzungsprodukt aus Adipinsäure und Dipropylenglykol (COOH:OH = 2:1)
• 0,5% Schwefelsäure (96%ig), oder Ameisensäure (85%ig)
• und weitere Laufzeit von 2 Stunden. Danach werden die Blössen über Nacht im Bad stehen gelassen (pH 3,8 im Blössenquerschnitt). Nach einer nochmaligen Laufzeit von 30 Minuten erfolgt ohne Flottenwechsel ein Zusatz von
• 2% eines elektrolytbeständigen Fettungsmittels auf Basis sulfitierter natürlicher Öle,
• 1% eines Emulgators auf anionischer Tensidbasis, z.B. Ammoniumsalz eines C₁₂-C₁₈-Alkylsulfats und weitere Laufzeit von 30 Minuten. Danach werden
• 6% eines basischen Chromgerbsalzes, z.B. Chromsal B^®der Firma Bayer AG
• zugegeben und 90 Minuten laufen gelassen. Im Anschluss erfolgt eine Zugabe von
• 3%AluminiumsilikatA,
• wonach nochmals 4 Stunden im Fass behandelt wird. An die Stelle des Aluminiumsilikats A können mit gleich gutem bzw. annähernd gleich gutem Effekt die Aluminiumsilikate B, D, J, K, M, P, treten. Der End-pH-Wert der Flotte beträgt 4,1-4,2. Der Restchromgehalt der Flotte beträgt 0,3 bis 0,9 g/I Chromoxid. Wird die Gerbung nach herkömmlichen Chromgerbverfahren vorgenommen, beträgt der Restchromgehalt dagegen 7-11 g/I Chromoxid.

After a short rinse at 20 ° C, ashed, decalcified and pickled beef bare in the usual way is pickled in the following way (pimples and tanning together):

• The bare are with
• 100% water
• 7% table salt
• Let run at 20 ° C in the barrel for 10 minutes. Then add
• 1.0% reaction product of adipic acid and dipropylene glycol (COOH: OH = 2: 1)
• 0.5% sulfuric acid (96%) or formic acid (85%)
• and another runtime of 2 hours. The pelts are then left overnight in the bath (pH 3.8 in the pelvic cross section). After another run of 30 minutes, without adding a fleet change of
• 2% of an electrolyte-resistant fatliquor based on sulfited natural oils,
• 1% of an anionic surfactant-based emulsifier, for example ammonium salt of a C ₁₂ -C ₁₈ -alkyl sulfate and a further running time of 30 minutes. After that
• 6% of a basic chrome tanning salt, for example Chromsal B ^® from Bayer AG
• added and let run for 90 minutes. Then add
• 3% aluminum silicate A,
• after which another 4 hours in the barrel is treated. Aluminum silicate A can be replaced by aluminum silicate B, D, J, K, M, P, with an equally good or approximately equally good effect. The final pH of the liquor is 4.1-4.2. The residual chromium content of the liquor is 0.3 to 0.9 g / l chromium oxide. If tanning is carried out using conventional chrome tanning processes, the residual chromium content is 7-11 g / l chromium oxide.

The percentages relate to the weight of the pimple and to the weight of the pelvis when tanning.

After completion, cloth-like soft, evenly tanned leather with a chromium content corresponding to 4.0% chromium oxide, based on 0% water content of the leather, is obtained.

Example 2 Chrome tanning of cowhide leather

• Die Blössen werden mit
• 100% Wasser,
• 7% Kochsalz (7,0 Be)
• bei 22°C im Fass 10 Minuten laufen gelassen. Anschliessend erfolgt ein Zusatz von
• 0,7% eines Gemisches technischer aliphatischer Dicarbonsäuren, (im wesentlichen Adipinsäure), 0,7% Schwefelsäure (96%ig)
• und weitere Laufzeit von 2 Stunden. Danach werden die Blössen über Nacht im Bad stehen gelassen (pH 3,7 im Blössenquerschnitt). Nach einer nochmaligen Laufzeit von 30 Minuten erfolgt ohne Flottenwechsel ein Zusatz von
• 5% eines basischen Chromgerbstoffs (Basizität 33% = 1,25% Chromoxid), (z.B. Chromosal B® der Firma Bayer AG),
• Laufzeit 90 Minuten. Im Anschluss erfolgt eine Zugabe von
• 2% Umsetzungsprodukt aus Adipinsäure und Dipropylenglykol (COOH:OH = 2:1)
• Laufzeit 90 Minuten. Danach Zusatz von
• 2,4% Aluminiumsilikat H
• Laufzeit nochmals 90 Minuten unter langsamen Aufheizen auf 35-40 °C.

After a short rinse at 20 ° C, ashed, decalcified and pickled bare bones are treated in the usual way in the following way (pimples and tanning together):

• The bare are with
• 100% water,
• 7% table salt (7.0 Be)
• Allow to run for 10 minutes at 22 ° C in the barrel. Then add
• 0.7% of a mixture of technical aliphatic dicarboxylic acids (essentially adipic acid), 0.7% sulfuric acid (96%)
• and another runtime of 2 hours. The pelts are then left in the bath overnight (pH 3.7 in the pelvic cross section). After another run of 30 minutes, without adding a fleet change of
• 5% of a basic chromium tanning agent (basicity 33% = 1.25% chromium oxide) (e.g. Chromosal B® from Bayer AG),
• Running time 90 minutes. Then add
• 2% reaction product of adipic acid and dipropylene glycol (COOH: OH = 2: 1)
• Running time 90 minutes. Then add
• 2.4% aluminum silicate H
• Running time again 90 minutes with slow heating to 35-40 ° C.

Aluminum silicate H can be replaced by aluminum silicate C, F, L, U, W with an equally good or approximately equally good effect.

The final pH of the liquor is 4.1. The residual chromium content of the broth is 0.33 g / l chromium oxide. In contrast, the residual chromium content in a conventional tanning process is between 7 and 11 g / l chromium oxide.

After completion, you get a soft, full and non-slip upper leather with a chromium content of 4.3% chromium oxide, based on 0% water content of the leather.

Example 3 Manufacture of cowhide leather

• Die Blössen werden mit
• 100% Wasser,
• 7% Kochsalz (7,0 Be)
• zunächst 10 Minuten bei 22°C laufen gelassen, danach unter weiterem Zusatz von
• 0,7% Gemisch technischer aliphatischer Dicarbonsäuren
• 0,7% Schwefelsäure (96%ig)
• noch 2 Stunden im Fass laufen gelassen. Der pH-Wert der Häute liegt zwischen 3,7 bis 3,9. Zusatz von 0,5% Emulgator (Aniontensid) Laufzeit 30 Minuten. Zusatz von
• 5,5% Chromgerbstoff in Form eines handelsüblichen basischen Chromgerbsalzes mit ca. 25% Cr₂0₃ (z.B. Chromosal B®, Bayer AG).
• 0,5% Umsetzungsprodukt aus Adipinsäure und Trimethylolpropan (COOH:OH = 5:3)
• Laufzeit 100 Minuten, danach Zugabe von 3% Aluminiumsilikat P,
• Laufzeit nochmals 90 Minuten, langsam auf 35-40 °C aufheizen. End-pH der Flotte 4,2. Die Leder werden in der Flotte über Nacht stehen gelassen und ab und zu bewegt. An die Stelle des Aluminiumsilikats P können mit gleich gutem bzw. annähernd gleich gutem Effekt die Aluminiumsilikate A, E, G, L, N, R, V treten.

After a short rinse at 20 ° C, washed, decalcified and pickled beef pelts are treated in the usual way in the following manner (pimples and tanning together):

• The bare are with
• 100% water,
• 7% table salt (7.0 Be)
• first run at 22 ° C for 10 minutes, then with the addition of
• 0.7% mixture of technical aliphatic dicarboxylic acids
• 0.7% sulfuric acid (96%)
• left to run for another 2 hours in the barrel. The pH of the skins is between 3.7 and 3.9. Add 0.5% emulsifier (anionic surfactant) running time 30 minutes. Addition of
• 5.5% chrome tanning agent in the form of a commercially available basic chrome tanning salt with approx. 25% Cr ₂ 0 ₃ (eg Chromosal B®, Bayer AG).
• 0.5% reaction product of adipic acid and trimethylolpropane (COOH: OH = 5: 3)
• Running time 100 minutes, then addition of 3% aluminum silicate P,
• Running time again 90 minutes, slowly heat up to 35-40 ° C. Final pH of the fleet 4.2. The leathers are left in the fleet overnight and occasionally moved. The aluminum silicate A, E, G, L, N, R, V can take the place of the aluminum silicate P with an equally good or approximately the same good effect.

The residual chromium content of the liquor is 0.55 g / I chromium oxide compared to a residual chromium content of 7-11 g / I chromium oxide in conventional tanning processes.

After the usual completion, upper leather of normal quality is obtained with a chromium content corresponding to 4.1% chromium oxide, based on 0% water content of the leather.

Example 4 Chrome tanning of cowhide leather

• 100% Wasser,
• 7% Kochsalz (7,0 Be)
• bei 20°C im Fass 10 Minuten laufen gelassen. Anschliessend erfolgt ein Zusatz von
• 0,6% Ameisensäure
• 0,7% Schwefelsäure (96%ig)
• und weitere Laufzeit von 2 Stunden. Danach werden die Blössen über Nacht im Bad stehen gelassen (pH 3,8 im Blössenquerschnitt). Nach einer nochmaligen Laufzeit von 30 Minuten erfolgt ohne Flottenwechsel ein Zusatz von
• 1% eines Emulgators auf anionischer Tensidbasis, z.B. Ammoniumsalz eines C₁₂-C₁₈-Alkylsulfats und weitere Laufzeit von 30 Minuten. Danach werden
• 5% eines basischen Pulverchromgerbstoffes (Basizität 33% = 1,25% Cr_z0₃), z.B. Chromosal B^O der Firma Bayer AG
• zugegeben und 90 Minuten laufen gelassen. Im Anschluss erfolgt eine Zugabe von
• 2,4%Aluminiumsilikat N,
• 2% Umsetzungsprodukt aus Adipinsäure und Dipropylenglykol (COOH:OH = 2:1)
• wonach nochmals 4 Stunden im Fass behandelt wird. Der End-pH-Wert der Flotte beträgt 4,1-4,2. An die Stelle des Aluminiumsilikates N können mit gleich gutem bzw. annähernd gleich gutem Effekt die Aluminiumsilikate U, S, P, K, J, C treten.

After a short rinse at 20 ° C, ashed, decalcified and pickled beef pelts are washed in the usual way in the following manner: The pelts are washed with

• 100% water,
• 7% table salt (7.0 Be)
• Allow to run for 10 minutes at 20 ° C in the barrel. Then add
• 0.6% formic acid
• 0.7% sulfuric acid (96%)
• and another runtime of 2 hours. The pelts are then left overnight in the bath (pH 3.8 in the pelvic cross section). After another run of 30 minutes, without adding a fleet change of
• 1% of an anionic surfactant-based emulsifier, for example ammonium salt of a C ₁₂ -C ₁₈ -alkyl sulfate and a further running time of 30 minutes. After that
• 5% of a basic powder chrome tanning agent (basicity 33% = 1.25% Cr _z 0 ₃ ), for example Chromosal B ^O from Bayer AG
• added and let run for 90 minutes. Then add
• 2.4% aluminum silicate N,
• 2% reaction product of adipic acid and dipropylene glycol (COOH: OH = 2: 1)
• after which another 4 hours in the barrel is treated. The final pH of the liquor is 4.1-4.2. The aluminum silicate N can be replaced by the aluminum silicate U, S, P, K, J, C with an equally good or approximately the same good effect.

The residual chromium content of the broth is 0.2 to 0.3 g / l chromium oxide compared to a residual chromium content of 6-10 g / l chromium oxide with conventional chrome tanning.

After normal completion, cloth-like soft, evenly tanned leather with a chromium content corresponding to 4.2% chromium oxide, based on 0% water content of the leather, is obtained.

Claims (17)

1. The use of water-insoluble, preferably water-containing aluminium silicates corresponding to the following general formula

in which Kat is an alkali metal ion and/or a difunctional and/or trifunctional cation, n is a number of from 1 to 3, x is a number of from 0.5 to 1.8, y is a number of from 0.8 to 50, preferably from 1.3 to 20, having a particle size from 0.1 11m to 5 mm and a calcium binding power of from 0 to 200 mg of CaO/g of anhydrous active substance, in conjunction with carboxylic acids containing ester and/or urethane and/or amide groups in the manufacture of leather.

2. The use claimed in Claim 1, the carboxylic acids having a molecular weight of from 170 to 30,000 and preferably from 310 to 10,000 and containing at least 2 carboxyl groups per molecule.

3. The use claimed in Claims 1 and 2, the carboxylic acids having been obtained by the reaction of di- and/or poly-carboxylic acids with compounds containing hydroxy and/or amino groups in a molar ratio

4. The use claimed in Claims 1 to 3, the carboxylic acids being reaction products of 2 moles of adipic acid and 1 mole of dipropylene glycol or of 5 moles of adipic acid and 3 moles of trimethylol propane.

5. The use claimed in Claims 1 to 4 together with aliphatic and/or aromatic di- and/or tri-carboxylic acids containing 2 to 8 C-atoms in the chain and/or their water-soluble hydrolysable partial esters with mono- or poly-hydric alcohols containing from 1 to 6 C-atoms.

6. The use claimed in Claims 1 to 5, aluminium silicates corresponding to the above formula in which Kat is an alkali metal ion, preferably a sodium ion, x is a number of from 0.7 to 1.5, y is a number of from 0.8 to 6, preferably 1.3 to 4 and which have a particle size of preferably from 1 to 12 µm and a calcium binding power of from 20 to 200 mg of CaO/g of anhydrous active substance being used.

7. The use claimed in Claims 1 to 5, aluminium silicates corresponding to the above formula in which at least 20 mole percent of Kat consists of alkali metal ions, preferably sodium ions, x is a number of from 0.7 to 1.5, y is a number of from 0.8 to 6, preferably from 1.3 to 4 and which have a calcium binding power of from 20 to 200 mg of CaO/g of anhydrous active substance being used.

8. The use claimed in Claims 1 to 5, aluminium silicates corresponding to the above formula in which y is a number of from >6 to 50 and preferably from >6 to 20 being used.

9. The use claimed in Claims 1 to 8, aluminium silicates corresponding to the above formula in which Kat is a sodium ion, an alkaline-earth metal ion, preferably a calcium or magnesium ion, a zinc ion, an aluminium ion or a mixture of these ions being used.

10. The use claimed in Claim 1, aluminium silicates which are at least partly soluble in acids at pH-values in the range from 2.5 to 5 and preferably at pH-values in the range from 3.5 to 4.5 being used.

11. The use claimed in Claim 10, aluminium silicates which have a calcium binding power of from 0 to <20 mg of CaO/g of anhydrous active substance being used.

12. The use claimed in Claims 10 and 11, aluminium silicates which are at least partly dissolved by a solution of 2.5 ml of concentrated formic acid in 100 ml of water being used.

13. The use claimed in Claims 10 to 12, aluminium silicates of which 2 g (based on anhydrous active substance) suspended in 100 ml of distilled water give a pH-value of the suspension above 2.5 on the addition with stirring of 2 ml of concentrated formic acid over a period of 8 to 30 minutes at a temperature of 22°C being used.

14. The use claimed in Claim 13, aluminium silicates which give a pH-value of the suspension of from 2.5 to 5,5 and preferably from 3.5 to 4.5 being used.

15. The use claimed in Claims 1 to 14, the carboxylic acids containing ester and/or urethane and/or amide groups being used in a quantity of from 1 to 20 g/I in the tanning liquor and/or in the pickle.

16. The use claimed in Claims 1 to 15, the aluminium silicates being used in the tanning liquor in a quantity of from 10 to 50 g/I, based on anhydrous product.

17. The use claimed in Claims 1 to 16 in the chrome tanning of leather.