Classifications

• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
  • C14C1/00—Chemical treatment prior to tanning
• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
  • C14C3/00—Tanning; Compositions for tanning
  • C14C3/02—Chemical tanning
• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
  • C14C1/00—Chemical treatment prior to tanning
  • C14C1/08—Deliming; Bating; Pickling; Degreasing
• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
  • C14C3/00—Tanning; Compositions for tanning
  • C14C3/02—Chemical tanning
  • C14C3/04—Mineral tanning
  • C14C3/06—Mineral tanning using chromium compounds

Definitions

• the invention relates to the use of water-insoluble, preferably water-containing aluminum silicates of the general formula. in the cat an alkali metal ion and / or a divalent and / or a trivalent cation, n is a number from 1 to 3, x is a number from 0.5 to 1.8, y is a number from 0, 8 to 50, preferably 1, 3-20 mean, with a particle size of 0.1 ⁇ to 5 mm, which have a calcium binding capacity of 0-200 mg CaO / g of anhydrous active substance, in conjunction with di- and / or tricarboxylic acids and / or their water-soluble hydrolyzable partial esters of leather production.
• tanning fur skins and leather In addition to degreasing and pre-tanning pimples, this is particularly the case when tanning fur skins and leather.
• other auxiliaries such as solvents and degreasing agents, tensides, electrolytes, phosphates, neutralizing agents, etc. are used in the processes of leather production.
• the aim of the invention is to reduce the use of chemicals and waste water in leather production; reduce.
• certain aluminum silicates are used in combination with di- and / or tricarboxylic acids and / or their water-soluble hydrolyzable partial esters, which enable a considerable reduction in the auxiliaries commonly used, in particular chromium tanning agents, and, as a result of their ecological safety, to significantly improve the wastewater situation to lead.
• chrome tanning is based on the formation of an azide complex and the agglomeration of the basic chromium salts with the carboxyl groups of the collagen.
• 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 a pH value of around 3-4.5 to form aluminum salts and polymeric silicas dissolve finest distribution.
• the aluminum silicates are self-dulling due to their own acid consumption.
• additional dulling agents can therefore be used to be dispensed with.
• the tanning liquor shows improved stability when dulling and the tanning of the skins is increased. Overall, the process control in tanning becomes more flexible and safer.
• the di- and / or tricarboxylic acids or their hydrolyzable partial esters can be used together with the aluminum silicates in the chrome tanning of leather.
• the addition of the acids or the partial esters can advantageously already take place in the strongly acidic pimple, that is to say before the actual tanning begins, since this achieves a high chromium content in the leather with a particularly uniform distribution.
• Suitable di- or tricarboxylic acids to be used according to the invention are aliphatic and / or aromatic carboxylic acids having 2 to 8 carbon atoms, such as Succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, aspartic acid, glutamic acid, phthalic acid, terephthalic acid, citric acid.
• hydrolyzable partial esters of these carboxylic acids with mono- or polyhydric alcohols with 1-6 C atoms can also be used in the same way.
• Such alcohols are e.g. B. methanol, ethanol, n- and iso-propanols, butanols, amyl alcohols, ethylene, propylene, butylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol.
• acidic Medium e.g. B. pimple or tanning liquor, hydrolyze relatively quickly.
• the aluminum silicates to be used according to the invention are amorphous, crystalline, synthetic and natural products which meet the conditions mentioned above.
• an alkali metal ion, preferably sodium ion, x is a number from 0.7 to 1.5
• y is a number from 0.8 to 6, preferably 1.3 to 4 whose particle size is 0.1 to 25 ⁇ , preferably 1 - 12 ⁇ , and which have a calcium binding capacity of 20-200 mg Ca0 / 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 ⁇ to 5 mm.
• Such alkali aluminum silicates can be prepared synthetically in a simple manner, for. B. by reaction of water-soluble silicates with water-soluble aluminates in the presence of water.
• 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.
• Alkali aluminum silicates can also be prepared from Al (OH) 3 , Al 2 0 3 or Si0 2 by reaction with alkali silicate or aluminate solutions.
• the alkali aluminum silicates prepared 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 present in aqueous suspension, amorphous or crystalline alkali aluminum silicate can be separated by filtration from the remaining aqueous solution and at temperatures of, for. B. 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, in particular 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 - 22 ⁇ , 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.
• 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 2 / n 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 80-95 ° C., with stirring, for at least 1/2 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 given above, still gives products with rounded corners and edges, especially if the deviation relates only to one of the four concentration parameters given above.
• water-soluble 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.
• 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.
• the precipitation product is heated to temperatures of 50-200 ° C. for 1/2 to 24 hours.
• useful dispersants such as sodium lauryl ether sulfate, sodium polyacrylate, hydroxy relihandiphosphonat and others to name a few.
• 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 represents.
• a further variant of the finely divided, water-insoluble alkali 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 ° C., preferably 130-160 ° C., for at least 1/2 hour, with vigorous stirring.
• 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 assemble into spherical particles, possibly hollow spheres of approximately 1 to 4 ⁇ m in diameter.
• Alkali aluminum silicates which can be prepared 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 Kat is an alkaline application, especially a Sodium cation means.
• 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.
• slurried kaolins consist mainly of the clay mineral kaolinite with the approximate composition Al 2 O 3 . 2 SiO 2 . 2 H 2 0, which has a layer structure.
• the kaolin In order to obtain the alkali aluminum silicates to be used according to the invention by hydrothermal treatment with alkali hydroxide, the kaolin must first be destructured, 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.
• 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, its iron content is around 2,000 to 10,000 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 action of sodium hydroxide on destructured kaolin produces a sodium aluminum silicate with a cubic, faujasite-like structure. / 11
• 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 metal 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 ⁇ m and are usually composed 100% of particles smaller than 10 ⁇ m.
• this conversion of the destructured kaolin is preferably carried out using sodium hydroxide solution and water glass. This creates a sodium aluminum silicate J, which has several names in the literature, e.g. B. is referred to as molecular sieve 13 X or zeolite NaX (see.
• 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 of SiO 2 : Na 2 O 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",
• 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 ⁇ m and also in coarser form with particle sizes of more than 25 ⁇ m 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 g e - wished particle size can be optionally followed by grinding and air classification set.
• Also suitable for the use according to the invention in leather production in combination with di- and / or tricarboxylic acids and / or their water-soluble hydrolyzed partial esters are aluminum silicates in which, in the above 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 ⁇ to 5 mm and a calcium binding capacity of 20-200 mg Ca0 / g of anhydrous active substance.
• 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.
• 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:
• the products contain about 8-27% by weight of water. They can be used in crystalline and amorphous form.
• Aluminum silicates suitable for the use according to the invention are those in which, in the above-mentioned formula Kat, an alkali metal ion and / or a divalent and / or a trivalent cation, x a number from 0.5 to 1.8, y a number from 0, 8-6, preferably 1.3-4, mean with a particle size of 0.1 p to 5 mm and a calcium binding capacity of 0 to ⁇ 20 mg CaO / g of anhydrous active substance.
• 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.
• Aluminum silicates can also be used for the use according to the invention in leather production, in which, in the aforementioned 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, y is a number> 6 to 50, preferably> 6 to 20, with a particle size of 0.1 ⁇ to 5 mm and a calcium binding capacity of 0-200 mg CaO / g of anhydrous active substance.
• 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.
• chrome tanning about 10 to 50 g / l aluminum silicate, based on the anhydrous product, is used in the tanning liquor.
• the di- and tricarboxylic acids or their water-soluble hydrolyzable partial esters are used in the tanning liquor in an amount of 1 to 20 g / l.
• Adipic acid and glutaric acid or their partial esters are preferred.
• the acid can also be added in the pimple, the amount is then also about 1 to 20 g / 1 liquor.
• the usual active ingredients and auxiliary substances e.g. anionic, cationic or nonionic surfactants, chromium salts etc. are used.
• the concentration of chromium salts in the tanning liquor can be reduced by 25-50% compared to the normal tanning processes.
• 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 3,000 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.
• the suspension of the precipitation product 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.
• the lye had been suctioned off from the crystal slurry and washed with deionized water
• the filter residue was dried until the washing water running off had a pH of approx. 10.
• the water contents were determined by heating the pre-dried products at 800 ° C for one hour. The up to the pH of. About 10 washed or neutralized and then dried sodium aluminum silicates were then ground in a ball mill. The grain size distribution was determined using a sedimentation balance.
• the maximum particle size was found to be 3 - 6 ⁇ .
• the sodium aluminum silicate C was first produced. After sucking off the mother liquor and washing the crystal mass with demineralized water to pH 10, the filter residue was suspended in 6.1 l of a 25% KCl solution. The suspension was briefly heated to 80-90 ° C; it was then cooled and filtered off and washed again.
• Alkali lye was placed in a stirred vessel and the calcined kaolin 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 filtered off with suction 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 further 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.
• 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 (blade mixer from Lödige) Homogenized for 20 minutes. With further mixing, the granulate formation was brought about within a further 8 minutes by gradually adding 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.).
• the calcium binding capacity of the product was 120 mg Ca0 / g active substance.
• the grain size was 0.08 to 2 mm.
• 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 g Ca0 / g active substance.
• the grain size was 0.08 to 2 mm.
• alkali aluminum silicates with particle sizes of more than 25 ⁇ 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.
• aluminosilicate L 50 kg were slurried in a 300 l stirred tank with 180 l of water and adjusted to a pH of 6 with 25% hydrochloric acid. The suspension was moderately stirred 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. With stirring, the granulate formation was brought about within a further 8 minutes by gradually adding 13.5 l of water adjusted to a pH of 6. The granules were dried at 150 ° C. for 60 minutes and solidified by heating at 780 ° C. for 15 minutes. The grain size distribution of the alumino-silicate O obtained in this way was 1 to 2 mm.
• the production of the aluminum silicates in which in the above-mentioned formula Kat 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 0.1 ⁇ 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 secondly y is a number from> 6 to 50 and the calcium binding capacity is 0 to 200 mg Ca0 / 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.
• the product obtained which is a synthetic crystalline zeolite (analcite), had the following characteristics:
• This aluminum silicate is a synthetic zeolite (mordenite), in which y has a value> 6 according to the aforementioned formula.
• 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:
• Other aluminum silicates in which y has a value> 6 according to the aforementioned formula are characterized below by commercially available products.
• Natural zeolite (Clinoptilolite), as it is extracted in large quantities in the open-cast mine in the western United States.
• the percentages relate to the weight of the pimple and to the weight of the skin when tanning.
• the aluminum silicate H can be replaced by the above-mentioned aluminum silicates A-G. and J-Z with an equally good or approximately equally good effect.
• the final pH of the liquor is 4.1 - 4.3.
• the residual chromium content of the liquor is 0.2 - 0.9 g / 1 chromium oxide.
• the residual chromium content in a conventional tanning process is between 7 and 11 g / 1 chromium oxide.
• the final pH of the liquor is 4.0 - 4.2.
• the residual chromium content of the liquor is 0.2 - 0.8 g / 1 chromium oxide compared to a residual chromium content of 7 - 11 g / l chromium oxide in conventional tanning processes.
• a soft, non-slip furniture leather of good quality is obtained with a chromium content corresponding to 4.2% chromium oxide, based on 0% water content of the leather.
• the residual chromium content of the liquor is 0.2 - 0.7 g / l chromium oxide compared to a residual chromium content of 7 - 11 g / l chromium oxide in conventional tanning processes.
• the residual chromium content of the liquor is 0.2 - 0.8 g / l chromium oxide compared to a residual chromium content of 7 - 11 g / l chromium oxide with conventional chrome tanning.
• the final pH of the liquor is 4.0 - 4.2.
• the residual chromium content of the liquor is 0.2 - 0.7 g / l chromium oxide compared to a residual chromium content of 7 - 11 g / 1 chromium oxide in conventional tanning processes.
• a soft, non-slip furniture leather of good quality is obtained with a chromium content corresponding to 4.1% chromium oxide, based on 0% water content of the leather.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Silicates, Zeolites, And Molecular Sieves (AREA)
• Treatment And Processing Of Natural Fur Or Leather (AREA)

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• 1978
  • 1978-05-20 DE DE19782822072 patent/DE2822072A1/de not_active Withdrawn
  • 1978-07-11 US US05/923,662 patent/US4221564A/en not_active Expired - Lifetime
• 1979
  • 1979-02-06 CA CA000320963A patent/CA1121109A/fr not_active Expired
  • 1979-02-08 KR KR7900378A patent/KR840002218B1/ko not_active Expired
  • 1979-05-15 TR TR20107A patent/TR20107A/xx unknown
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  • 1979-05-17 HU HU79HE784A patent/HU180777B/hu not_active IP Right Cessation
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