GB1603720A - Creación de Inventos y Patentes con Inteligencia Artificial

GB1603720A – Use of fine-particle water-insoluble alkali metal aluminium silicates in the production of leather
– Google Patents

GB1603720A – Use of fine-particle water-insoluble alkali metal aluminium silicates in the production of leather
– Google Patents
Use of fine-particle water-insoluble alkali metal aluminium silicates in the production of leather

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Publication number
GB1603720A

GB1603720A
GB19469/78A
GB1946978A
GB1603720A
GB 1603720 A
GB1603720 A
GB 1603720A
GB 19469/78 A
GB19469/78 A
GB 19469/78A
GB 1946978 A
GB1946978 A
GB 1946978A
GB 1603720 A
GB1603720 A
GB 1603720A
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United Kingdom
Prior art keywords
tanning
alkali metal
leather
aluminium silicate
water
Prior art date
1977-07-16
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)

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GB19469/78A
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Henkel AG and Co KGaA

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Henkel AG and Co KGaA
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1977-07-16
Filing date
1978-05-15
Publication date
1981-11-25

1978-05-15
Application filed by Henkel AG and Co KGaA
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Henkel AG and Co KGaA

1981-11-25
Publication of GB1603720A
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patent/GB1603720A/en

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legal-status
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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

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

C14C5/00—Degreasing leather

Description

(54) THE USE OF FINE-PARTICULATE WATER
INSOLUBLE ALKALI METAL ALUMINIUM
SILICATES IN THE PRODUCTION OF LEATHER
(71) We, HENKEL KOMMANDITGESELLSCHAFT AUF AKTIEN, a
German company, of 67 Henkelstrasse, 4000 Dusseldorf-Holthausen, Federal
Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to the use of fine particulates, water-insoluble alkali metal aluminium silicates in the production of leather.
One of the most acute problems in the production of leather is the partial or full replacement of auxiliary agents which heavily contaminate the industrial waste waters. This is particularly the case during the degreasing and pre-tanning of smooth pickled skins and when tanning pelts and leather. In these processes, auxiliary agents such as solvents and degreasing agents, surfactants, electrolytes, phosphates, neutralizing agents etc. are used in addition to tanning substances.
By practice of the invention the use of chemicals and the pollution of the waste waters during the production of leather may be reduced. For this purpose and in accordance with the present invention, specific alkali metal aluminium silicates are used which can partially or fully replace the auxiliary agents normally used and which, owing to their ecological harmlessness, lead to a considerable improvement in the state of the waste waters.
The use of alkali alkali aluminium silicates has proved to be advantageous, particularly in the following stages:
A. Degreasing and pre-tanning of smoothed pickled skins
The smoothed pickled skins nowadays frequently used as the starting material for the production of leather are pre-treated with salt and acid and are thus preserved. The pH value of the material in this state is < 2. When performing the degreasing process before the actual tanning operation, it is essential to ensure that damage to the structure of the skin by swelling is avoided. This is generally effected by concentrated salt solutions (60 to 80/by). According to the tanning method, anionic or nonionic surfactants and, possibly, solvents are added to the liquors for the purpose of degreasing. Since the tanning action of polyphosphates has become known, polyphosphates such as hexamethaphosphate are added when softening and degreasing the skin material. Swelling is prevented by the slight tanning action of these polyphosphates. However, the tanning action itself is not sufficiently pronounced to determine the character of the leather in this state of production. The use of alkali metal aluminium silicates in the degreasing and pre-tanning of smoothed pickled hides has, in particular, the following advantages: 1. The risk of the eutrophication of waters, caused by waste waters containing phosphate, is prevented by the saving of phosphates. 2. The use of solvents for the degreasing of the smoothed pickled hides can be partially or fully dispensed with. 3. The alkali metal aluminium silicates have a considerable capacity for binding acid and thus have a de-pickling effect. 4. The formation of troublesome coloured chromium-phosphate complexes during the subsequent chrome tanning operation, known from the use of polyphosphates, is avoided. B. Tanning of pelts and leather By far the most important method of tanning is that of chrome tanning. It is based on the formation of azido complexes and the agglomeration of the basic chromium salts with the carboxyl groups of the collagen. In addition to this, other basic metallic salts such as those of iron, aluminium, zirconium, titanium and silicon also have tanning properties. In practice, however, only specific aluminium and zirconium salts have proved to be successful as combination tannin substances. Silicon compounds are virtually not used, since the starting materials, generally special water glasses, are difficult to handle in an acid tanning medium. In addition, the quality of the leather is generally inadequate, especially after ageing, since hardening, a brittle feel and loss 6f resistance to tearing can occur. e use of alkali metal aluminium silicates leads to the following advantages, particularly in the case of chrome tanning or combination tanning with chromium-, aluminium- and silicon tanning substances: 1. The pollution of the waste waters of the tannery is considerably reduced by reducing the quantity of chrome tanning substances. The chromium content is thereby reduced more than proportionally. When reducing the quantity of chrome by 50 /O in the liquor, the waste waters contain only up to 15% of the conventional quantity compared with pure chrome tanning, as is shown in a publication by Dr. Ing. Siegfried Felten in "Wasser, Luft und Betrieb", Issue 3, 1964. 2. The described disadvantages of silicon tanning substances are avoided, since the alkali metal aluminium silicates in the acid medium (pH 34.5) present during tanning dissolve to form finely distributed sodium salts, aluminium salts and polymeric silicic acids. 3. During combination tanning, the alkali metal aluminium silicates have a self-neutralizing effect owing to their own consumption of acid. Thus, there is no need to use additional neutralizing agents. The tanning action is at the same time enhanced. 4. The alkali metal aluminium silicates, to be used in accordance with the present invention, can be used as neutralizing agents when neutralizing chrome leathers, without the leathers being changed to an unpleasant green colour by polyphosphates. The alkali metal aluminium silicates at the same time act as a masking salt, thereby avoiding the precipitation of highly basic chromium salts. An after-tanning effect is also obtained. 5. Common salt and other electrolytes can be partially or fully dispensed with, so that the waste waters contain only small quantities of electrolytes compared with the conventional method. 6. The alkali metal aluminium silicates can be readily stored and handled without risk. The present invention provides a method for the production of leather from washed and cleaned hides or pelts, in which the washed and cleaned hides or pelts are subsequently contacted with a fine-particulate water-insoluble alkali metal aluminium silicate, preferably containing water, of the general formula (Cat2O).Al2O3.(SiO2), in which Cat represents an alkali metal ion, preferably a sodium ion, x represents a number of from 0.7 to 1.5, y represents a number of from 0.8 to 6, preferably 1.3 to 4, which alkali aluminium silicate has a particle size of from 0.1 to 25y, preferably of from 1 to 12,a, and a calcium binding capacity of 20 to 200 mg CaO/g of anhydrous active substance. The present invention includes said method in which the hides or pelts have been subjected to a treatment to produce smooth pickled skins and said alkali metal aluminium silicate is used in at least one of the stages applied to such smooth pickled skins in the production of leather therefrom. The use of alkali metal aluminium silicates in the washing and cleaning of raw hides or pelts is described and claimed in co-pending application No. 19503/78. Serial No. 1587110. The method according to the present invention is carried out in the highly acidic pH range. The calcium binding capacity is determined by the method given in Examples. The alkali metal aluminium silicates, to be used in accordance with the present invention, can be produced 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 a solid state may be reacted with the other component present in the form of an aqueous solution. The desired aluminium silicates are also obtained by mixing the two components, present in a solid state, in the presence of water. Alkali metal aluminium silicates can also be produced from Al(OH)3, Awl203 or SiO2 by reaction with alkali silicate solutions or aluminate solutions.Finally, substances of this type are also formed from the melt, although, owing to the high melting temperatures required and the necessity of converting the melt into finely distributed products, this method appears to be less interesting from an economic viewpoint. The alkali metal aluminium silicates produced by precipitation, or converted to an aqueous suspension in a finely distributed state by other methods, may be converted from the amorphous state into the aged or the crystalline state by heating to temperatures of from 50 to 2000 C. The amorphous or crystalline alkali metal aluminium silicate, present in an aqueous suspension, can be separated from the remaining aqueous solution by filtration and can be dried at temperatures of, for example, 50 to 8000 C. The product contains a greater or smaller quantity of bound water according to the drying conditions.Anhydrous products are obtained at 800"C. However, the hydrated products are preferred, particularly those which are obtained when drying at 50 to 4000 C, particularly 50 to 2000 C. By way of example, suitable products can have water contents of approximately 2 to 30 /O usually approximately 8 to 27%, relative to their total weight. The precipitation conditions can contribute to the formation of the required small particle sizes of from 1 to 1 2,a, the intermixed aluminate and silicate solutions, which may also be introduced simultaneously into the reaction vessel, being subjected to high shearing forces by, for example, intensively agitating the suspension. When crystallized alkali metal aluminium silicates are ro produced (these are preferably used in accordance with the present invention) the formation of large, possibly interpenetrating crystals is thus prevented by slow agitation of the crystallizing compound. Nevertheless, undesired agglomeration of crystal particles can occur during drying, so that it may be advisable to remove these secondary particles in a suitable manner by, for example, air separators. Alkali metal aluminium silicates obtained in a coarser state, and which have been ground to the desired grain size, can also be used. By way of example, mills and/or air separators, or combinations thereof, are suitable for this purpose. Preferred products are, for example, synthetically produced crystalline alkali metal aluminium silicates of the composition 0.7-1.1 Cat2O.Al2O3.l.3-3.3 SiO2 in which Cat is an alkali cation, preferably a sodium cation. It is advantageous when the alkali metal aluminium silicate crystallites have rounded edges and corners. If it is desired to produce the alkali metal aluminium silicates with rounded corners and edges, it is advantageous to start with a preparation whose molar composition lies preferably in the range 2.5--6.0 Cat2O.AI203.0.95.0 SiO2.60200 H2O wherein Cat2 has the meaning given above and, in particular, signifies the sodium ion. This preparation is crystallized in a conventional manner. Advantageously, this is effected by heating the preparation for at least 1/2 hour to 70 to 1200C, preferably to 80 to 950C, under agitation. The crystalline product is isolated in a simple manner by separating the liquid phase. If required, it is advisable to rewash the products with water, and to dry them, before further processing.Even when working with a preparation whose composition differs slightly from that stated above, one still obtains products having rounded corners and edges, particularly when the difference only relates to one of the four concentration parameters given above. Furthermore, in accordance with the present invention, fine-particulate waterinsoluble alkali metal aluminium silicates may also be used which have been precipitated and aged or crystallized in the presence of water-soluble inorganic or organic dispersing agents. Products of this type are obtainable in a technically simpler manner. Suitable water-soluble organic dispersing agents are surfactants, non-surfactant-like aromatic sulphonic acids and compounds having a complexforming capacity for calcium. The said dispersing agents may be introduced into the reaction mixture in an optional manner before or during precipitation, and, for example, they may be introduced in the form of a solution or they may be dissolved in the aluminate solution and/or silicate solution. Particularly satisfactory effects are obtained when the dispersing agent is dissolved in the silicate solution.The quantity of dispersing agent should be at least 0.05 percent by weight, preferably 0.1 to 5 percent by weight, relative to the total starting solution. The starting solution is heated to temperatures of from 50 to 200"C for 1/2 hour to 24 hours for the purpose of ageing or crystallization. Some of the large number of dispersing agents which may be used are, for example, sodium lauryl ether sulphate, sodium polyacrylate, hydroxyethane diphosphonate, and others. Compounds of the general formula 0.7-1.1 Na2O.AI203. > 2.43.3 SiO2 constitute a special variant, with respect to their crystal structure, of the alkali metal aluminium silicates to be used in accordance with the present invention. The possibility of their use as soaping aids does not differ from that of the other alkali metal aluminium silicates which have been mentioned.
Compounds of the formula 0.7 Na2O.AI203 > 3.35.3 SiO2 constitute a further variant of the fine-particulate, water-insoluble alkali metal aluminium silicates to be used in accordance with the present invention. When producing products of this type, one commences with a preparation whose molar composition lies preferably in the range 2.54.5 NO; Awl203; 3.56.5 SiO2; 50110 H2O
This preparation is crystallized in a conventional manner. Advantageously, this is effected by heating the preparation for at least 1/2 hour to 100 to 2000C, preferably 130 to 1600C, under vlgorous agitation. The crystalline product is isolated in a simple manner by separation of the liquid phase.If required, it is advisable to wash the products with water before further processing and to dry them at temperatures of from 20 to 200″C. The products thus dried still contain bound water. When the products are produced in the manner described, one obtains very fine crystallites which agglomerate to form spherical particles, possibly to form hollow balls having a diameter of approximately 1 to 4,u.
Furthermore, alkali metal aluminium silicates suitable for use in accordance with the present invention are those which can be produced from calcinated (destructured) kaolin by hydrothermal treatment with aqueous alkali hydroxide.
The formula 0.7-1.1 Cat2O.AI203.1.32.4 SiO2.0.55.0 H2O corresponds to the products, Cat signifying an alkali cation, particularly a sodium cation. The production of the alkali metal, aluminium silicates from calcinated kaolin leads, without any special technical expense, directly to a very fineparticulate product. The kaolin, previously calcinated at 500 to 8000 C, is hydrothermally treated with aqueous alkali hydroxide at 50 to 1000C. The crystallization reaction thereby taking place is generally concluded after 0.5 to 3 hours.
Commercially available, elutriated kaolins predominantly comprise the clay mineral kaolinite of the approximate composition Awl203.2 SiO2.2 H2O and which has a layer structure. In order to obtain the alkali metal aluminium silicates, to be used in accordance with the present invention, therefrom by hydrothermal treatment with alkali hydroxide, it is first necessary to destructure the kaolin, this being effected to best advantage by heating the kaolin to temperatures of from 500 to 800″C for two to four hours. The X-ray amorphous anhydrous metakaolin is thereby produced from the kaolin. In addition to destructuring the kaolin by calcination, the kaolin can also be destructured by mechanical treatment (grinding) or by acid treatment.
The kaolins usable as starting materials are light-coloured powders of great purity; of course, their iron content of approximately 2000 to 10,000 ppm Fe is substantially higher than the values of from 20 to 100 ppm Fe in the alkali metal aluminium silicates produced by precipitation from alkali metal silicate and alkali metal aluminate solutions. This higher iron content in the alkali metal aluminium silicates produced from kaolin is not disadvantageous, since the iron is firmly embedded in the form of iron oxide in the alkali metal aluminium silicate lattice and is not dissolved out. A sodium aluminium silicate having a cubic, faujasite-like structure is produced during the hydrothermal action of sodium hydroxide on destructured kaolin.
Alkali metal aluminium silicates, usable in accordance with the present invention, may also be produced from calcinated (destructured) kaolin by hydrothermal treatment with aqueous alkali hydroxide with the addition of silicon dioxide or a compound producing silicon dioxide. The mixture of alkali metal aluminium silicates of differing crystal structure generally obtained thereby comprises very fine-particulate crystal particles having a diameter of less than 20y, and 100% of which usually comprises particles having a diameter of less than 10u.
In practice, this conversion of the destructured kaolin is effected preferably with soda lye and water glass. A sodium aluminium silicate J is thereby produced which is known by several names in the literature, for example, molecular sieve 13 X or zeolite NaX (see O. Grubner, P. Jiru and M. Ralek, «Molecular Sieves», Berlin 1968, pages 32, 85 to 89), when the preparation is preferably not agitated during the hydrothermal treatment, at all events when only low shearing energies are used and the temperature preferably remains at 10 to 200C below the boiling temperature (approximately 1030C). The sodium aluminium silicate J has a cubic crystal structure similar to that of natural faujasite.The conversion reaction may be influenced particularly by agitating the preparation, by elevated temperature (boiling point at normal pressure or in an autoclave) and greater quantities of silicate, that is, by a molar preparation ratio SiO2:Na2O of at least 1, particularly 0.1 to 1.45, such that sodium aluminium silicate F is produced in addition to, or instead of, sodium aluminium silicate J. Sodium aluminium silicate F is designated «zeolite
P» or «type B» in the literature (see D. W. Breck, «Zeolite Molecular Sieves», New
York, 1974, page 72). Sodium aluminium silicate F has a structure similar to the natural zeolites gismondine and garronite and is present in the form of crystallites having an externally spherical appearance.In general, the conditions for producing the sodium aluminium silicate F and for producing mixtures of J and F are less critical than those for a pure crystal type A.
Smoothed pickled skins are degreased and pre-tanned in a known manner, for example, in a tanning vat. The alkali metal aluminium silicates are used preferably in combination with surfactants, particularly anionic and non-ionic surfactants.
Particularly suitable anionic surfactants are higher sulphates or sulphonates having 8 to 18 carbon atoms, such as primary and secondary alkylsulphates, alkylsulphonates or alkylarylsulphonates. Suitable non-ionic surfactants are, for example, the adducts of from 5 to 30 mol of ethylene oxide to higher fatty alcohols, alkylphenols, fatty acids or fatty amines having 8 to 18 carbon atoms. It is advantageous to use the anionic and non-ionic surfactants in the form of a mixture or, alternatively, individually, according to the commodity to be washed. In addition to this, it is possible to add the alkali metai aluminium silicates as separate auxiliary agents to conventional liquors, or to use them combined with a small proportion of acid chromium tanning substances.
In the case of the process in accordance with the present invention, 10 to 50 g/l of surfactants and 10 to 50 gfl of alkali metal aluminium silicate are required.
Furthermore, grease solvents in quantities of from 50 to 100 g/l may be added to assist the grease-dissolving action of the cleaning liquor when degreasing smoothed pickled skins having a high content of fat. Suitable solvents are chosen from the group of petroleum hydrocarbons, hydroaromatics, alkylbenzenes and mineral oils. In general, however, it is possible to dispense with the use of solvents.
The tanning of pelts and leather is also performed in a conventional manner, the known tanning substances, such as vegetable-synthetic tanning substances and chrome tanning substances being used according to the type of leather, with the addition of electrolytes such as common salt, inorganic or organic acids such as sulphuric acid, formic acid or acetic acid. Pickling and tanning can be combined with one another in a conventional manner. The leather can be subsequently aftertanned and greased.
In the tanning processes specified, the quantity of alkali metal aluminium silicate used is 5 to 80 grammes per litre of tanning liquor.
Alkali metal aluminium silicates can also be used to advantage in the neutralizing of the leather, since they decompose in the acid medium with the binding of acid and the formation of alkali- and aluminium salts and polymeric silicic acids. In this case, 2 to 20 of of alkali metal aluminium silicates are required.
The initially mentioned advantages over the conventional processes are obtained by the use, in accordance with the present invention, of fine-particulate water-insoluble alkali metal aluminium silicates. The alkali metal aluminium silicates can be readily converted as dry powders into stable dispersions by stirring them into water or solutions containing dispersing agents, and can be satisfactory used in this form and can be readily diluted with water.
The present invention will now be further illustrated by way of the following
Preparations and Examples in which all percentages are percentages by weight.
Preparations
Production of suitable alkali metal aluminium silicates
The silicate solution was added to the aluminate solution under vigorous agitation in a vessel having a capacity of 15 litres. Agitation was effected at 3000 r.p.m. by means of an agitator having a dispersing disc. The two solutions were at room temperature. An X-ray amorphous sodium aluminium silicate was formed as a primary product of precipitation under exothermic reaction. After agitating for 10 minutes, the suspension of the product of precipitation was transferred to a crystallizer and, for the purpose of crystallization, remained in the crystallizer for 6 hours at 90QC under agitation (250 r.p.m.). The filtration residue was dried after drawing off the liquor from the crystal sludge and washing it with deionized water until the water flowing off had a pH value of approximately 10.Instead of the dried sodium aluminium silicates, the suspension of the crystallization product or the crystal sludge was also used to produce the soaping aids. The water contents were determined by heating the pre-dried products to 800″C for I hour. The sodium aluminium silicates were washed or neutralized to a pH value of approximately 10 and were then dried and were subsequently ground in a ball mill. The grain size distribution was determined by means of a sedimentation balance.
The calcium binding capacity of the aluminium silicates was determined in the following manner:
1 g of aluminium silicate (relative to AS) is added to Il of an aqueous solution containing 0.594 g of CaCI2 (=300 mg Caps=300 dH) and adjusted to a pH value of 10 with diluted NaOH. The suspension is then vigorously agitated for 15 minutes at a temperature of 22″C (-20C). The residual hardness x of the filtrate is determined after filtering-off the aluminium silicate. The calcium binding capacity is calculated therefrom in mg CaO/g AS in accordance with the formula: (30-x).10.
When the calcium binding capacity is determined at higher temperatures, for example at 600C, the values obtained are considerably better than those obtained at 22″C.
Conditions for producing the sodium aluminium silicate A:
Precipitation: 2.985 kg of aluminate solution of the
composition 17.7% Na2O, 15.8fez Al203,
66.6% H2O
0.15 kg of caustic soda
9.420 kg of water
2.445 kg of a 25.8% sodium silicate solution
of the composition 1 Na2O.6.0 SiO2 freshly
prepared from commercially available water
glass and slightly alkali-soluble silicic acid
Crystallization: 6 hours at 90″C Drying: 24 hours at 1000C Composition: 0.9 Na2O.l Awl203.2.04 SiO2.4.3 H2O (=21.6″b 1120) Degree of crystallization: fully crystalline.
Calcium binding capacity: 170 mg Ca/g active substance.
The particle size distribution, determined by sedimentation analysis, resulted in a maximum particle size of 3 to 6,a.
The sodium aluminium silicate A exhibits the following interference lines in the X-ray diffraction graph:
d-values taken with Cu-K, radiation in A
12.4
8.6
7.0
4.1 (+)
3.68 (+)
3.38 (+)
3.26 (+)
2.96 (+)
2.73 (+)
2.60 (+)
It is quite possible that all these interference lines will not appear in the X-ray diffraction graph, particularly when the aluminium silicates have not been fully crystallized.Thus, the d-values which are most important for characterising these types have been indicated with a
Conditions for producing the sodium aluminium silicate B:
Precipitation: 7.63 kg of an aluminate solution of the
composition 13.2% Na2O; 8.0% Awl203; 78.8% H2O;
2.37 kg of a sodium silicate solution of the
composition 8.0% Na2O; 26.9% SiO2; 65.1% H2O; Preparation ratio in mol: 3.24 Na2O; 1.0 Awl203; 1.78 SiO2; 70.3 H2O; Crystallization: 6 hours at 900C;
Drying: 24 hours at 100″C; Composition of the dried 0.99 Na2O.1.00 Awl203.1.83 SiO2 product: .4.0 H2O; (=20.9% H2O) Crystalline form:Cubic with greatly rounded corners and
edges;
Average particle diameter: 5.4,u Calcium binding capacity: 172 mg CaO/g of active substance.
Conditions for producing the sodium aluminium silicate C:
Precipitation: 12.15 kg of an aluminate solution of the
composition 14.5% Na2O; 5.4% Awl203 80.1% H,O; 2.87 kg of a sodium silicate solution of the
composition 8.0% Na2O; 26.9% SiO2; 65.1% H2O; Preparation ratio in mol: 5.0 Na2O; 1.0 Awl203; 2.0 SiO2; 100 H2O; Crystallization: 1 hour at 900C;
Drying: Hot atomization of a suspension of the
washed product (pH 10) at 2950C; 46%
content of solid substances in the
suspension;
Composition of the dried 0.96 Na2O.I Awl203. 1.96 product: SiO2.4 H2O;
Crystalline form:Cubic with greatly rounded corners and
edges; water content 20.5%
Average particle diameter: 5.4y Calcium binding capacity: 172 mg CaO/g of active substance.
Conditions for producing the potassium aluminium silicate D:
The sodium aluminium silicate C was produced in the first instance. After the mother liquor had been drawn off, and the crystalline mass had been washed to the pH value 10 with demineralised water, the filtration residue was suspended in 6.1 1 of a 25% KCI solution. The suspension was heated for a short time to 80 to 90″C, and was then cooled, filtered off again and washed.
Drying: 24 hours at 1000C;
Composition of the dried 0.35 Na2O.0.66 K2O. 1.0 Al2O3.1.96 product: SiO2.4.3 H2O; (water content 20.3%)
Conditions for producing the sodium aluminium silicate E:
Precipitation: 0.76 kg of aluminate solution of the
composition 36.0% Na2O, 59.0 NO of Al2O3, 5.00/, water;
0.94 kg of caustic soda;
9.49 kg of water;
3.94 kg of a commercially available sodium
silicate solution of the composition 8.0%
Na2O, 26.9% SiO2, 65.1% H2O; Crystallization: 12 hours at 900C;
Drying: 12 hours at 1000C; Composition: 0.9 Na2O.l Al2O3.3.1 SiO2.5 H2O; Degree of crystallization: Fully crystalline.
Maximum particle size was: 3 to 6,u.
Calcium binding capacity: 110 mg CaO/g active substance.
The aluminium silicate E exhibits the following interference lines in the X-ray diffraction graph:
d-values, taken with Cu-Ka radiation in A
14.4
8.8
4.4
3.8
2.88
2.79
2.66
Conditions for producing the sodium aluminium silicate F:
Precipitation: 10.0 kg of an aluminate solution of the
composition 0.84 kg NaAlO2+0. 17 kg NaOH+1.83 kg H2O; 7.16 kg of a sodium silicate solution of the
composition 8.0% Na2O, 26.9% SiO2, 65.1 ó H2O; Crystallization: 4 hours at 150″C; Drying: Hot atomization of a 30% suspension of the
washed product (pH 10);
Composition of the dried 0.98 Na2O.l Al203.4.12 SiO2.
product: 4.9 H2O;
The particles are of the average diameter of the balls is spherical shape: 3 to 6,a Calcium binding capacity: 132 mg CaO/g active substance at 50″C.
Conditions for producing the sodium aluminium silicate G:
Precipitation: 7.31 kg of aluminate (14.8% Na2O, 9.2% Awl203, 76.0% H2O); 2.69 kg of silicate (8.0/o Na2O, 26.9% SiO2,
65.1% H2O): Preparation ratio in mol: 3.17 Na2O, 1.0 Awl203, 1.82 SiO2, 62.5 H2O; Crystallization: 6 hours at 900C;
Composition of the dried 1.11 Na2O.I Awl203.1.89 SiO2, product: 3.1 H2O(=16.4% H,O); Crystalline structure: Mixed structural type in the ratio 1:1;
Crystalline form: Rounded crystallites;
Average particle diameter: 5.6,u; Calcium binding capacity: 105 mg CaO/g of active substance at 50 C.
Conditions for producing the sodium aluminium silicate H
produced from kaolin: 1. Destructuring kaolin
In order to activate the natural kaolin, samples of 1 kg were heated to 7000C in a fire-clay crucible for 3 hours. The crystalline kaolin Awl203.2 SiO2.2H2O was thereby converted to the amorphous metakaolin A12O3:2 SiO2.
2. Hydrothermal treatment of the metakaolin
Alkali solution was placed into an agitating vessel and the calcinated kaolin was added under agitation at temperatures between 20 and 100″C. The suspension was brought to the crystallization temperature of 70 to 100″C under agitation, and was maintained at this temperature until the crystallization operation had terminated. The mother liquor was subsequently drawn off and the residue was washed with water until the water draining off had a pH value of from 9 to 11. The filter cake was dried and was subsequently crushed to a fine powder or was ground to remove the agglomerates produced during drying. This grinding process was omitted when the filtration residue was further processed in a wet state, or when the drying operation was Performed by means of a spray drier or a now drier.
Alternatively, the hydrothermal treatment of the calcinated kaolin can be performed in a continuous operation.
Preparation: 1.65 kg of calcinated kaolin 13.35 kg of 10%
NaOH, mixed at room temperature;
Crystallization: 2 hours at 1000C;
Drying: 2 hours at 1600C in a vacuum drying
cabinet;
Composition: 0.88 Na2O.1 Awl203.2.14 SiO2.3.5 H2O (=18.1% H,O); Crystalline structure: Mixed structural type like Na aluminium
silicate G, although in the ratio 8:2;
Average particle diameter: 7.our.
Calcium binding capacity: 126 mg CaO/g active substance.
Conditions for producing the sodium aluminium silicate J produced from kaolin:
The destructuring of the kaolin in the same manner as in the case of the sodium aluminium was effected Preparation: 2.6 kg of calcinated kaolin,
7.5 kg of 50% NaOH,
7.5 kg of water glass,
51.5 kg of deionized water, mixed at room
temperature;
Crystallization: 24 hours at 1000C, without agitation;
Drying: 2 hours at 1600C in a vacuum drying
cabinet;
Composition: 0.93 Na2O.1 Al2O3.3.60 SiO2.6.8 H2O
(=24.6% H2O); Crystalline structure: Sodium aluminium silicate J) in accordance
with above definition, cubic crystallites:
Average particle diameter:
Calcium binding capacity: 105 mg CaO/g active substance.
EXAMPLES
Example 1
Degreasing and pre-tanning of smoothed pickled sheepskins for vegetall tanned lining leather:
Smoothed pickled sheepskins (pH 1.8 in the skin) are fulled for 90 minutes in a vat with 50 /O water 380 C, 3% alkylphenolpolyglycol ether (9.5 EO),
5% Na-AI silicate in accordance with Examples A, B, E, subsequently diluted with 100% of water of 38″C and fulled for a further 60 minutes (pH of the skin 3.8 to 4.0). The liquor is disposed of, and the skins are washed for 15 minutes with water at 350C.
Tanning:
The degreased and pre-tanned skins are fulled for 15 minutes with
100% water 250C, 10% of a synthetic bright- and mild- tanning substance of a commercially
available type, and subsequently fulled for 45 minutes in the same liquor with
4% additive of a commercially available greasing agent resistant to tanning
substance, and tanned for 4 hours with
10% mimosa tanning substance (powder) added jointly
10% quebracho tanning substance (powder)
The leathers are subsequently treated and brightened for 30 minutes in a fresh liquor with 100% of water and 0.5/c of oxalic acid, the pH value being established at approximately 4.1 to 4.2 in the bath.
After the leathers had been rinsed for 10 minutes at 25″C, they were stretched and hang-dried in a conventional manner.
Lining leather of good quality is obtained without the large quantities of ecologically harmful salts or polyphosphates otherwise required when degreasing and pre-tanning.
Example 2
Degreasing and pre-tanning of smoothed pickled sheepskins for
chrome-tanned nappa clothing leather:
The defleshed smoothed pickled skins are degreased and pretanned in the same manner as in Example 1 (pH 3.8 to 4.0 in the skin). The skins are subsequently rinsed at 350C until the liquor flows off in a clear state.
Tannin 100 /O water 250C,
5% of a commercially available synthetic light-tanning substance resistant to
chrome tanning substances,
30 minutes in the vat, subsequent addition of 20% of a commercially available
mild-tanning chrome tanning substance;
Duration of tanning 5 hours (pH approximately 3.8 in the bath);
Leather propped up for 1 to 2 days and subsequently folded.
After-tanning:
200% water 45″C Rinsed for 10 minutes, fresh liquor,
100% water 450C,
3% of a mild-tanning commercially available chrome tanning substance duration 15 minutes,
2% of a greasing agent which is resistant to chrome tanning substance and
resistant to light–45 minutes,
4% of a mild-tanning, neutral auxiliary tanning substance–duration 30
minutes,
pH 4.4 in the bath, subsequent rinsing at 50″C–10 minutes.
Greasing:
150% water 500C, 57% commercially available softening leather-greasing agents, natural or
synthetic, duration 45 minutes.
The leathers are further processed in a conventional manner and hang-dried.
Nappa leather of good quality is obtained in this manner without the otherwise conventional and necessary joint use of common salt or polyphosphate for the purpose of depickling and degreasing.
Example 3
Tanning of sheephides:
Well washed and, if necessary, bleached sheep hides are rinsed for 15 minutes at 35″C in a hide winch.
Pickling and tanning:
Water, 30 to 35″C, liquor ratio 1:20.
60 gfl of common salt,
5 gfl of a commercially available, electrolyte-resistant pelt-greasing agent,
duration 30 minutes,
5 gfl of organic low-molecular acids, such as mixtures of acetic acid and formic
acid, duration 3 hours, left standing in the bath overnight, 4–5 gfl of commercially available pulverulent chrome tanning substance,
7 gfl Na-AI silicate according to Examples A, B, C, duration 3 hours,
subsequently left standing overnight (pH approximately 4.0 in the liquor), subsequently rinsed for 15 minutes, propped up and hang-dried.
Between 1/3 and half the quantity of chrome tanning substance normally used is saved in this manner, whereby the ecologically harmful chromium content in the waste water is reduced to approximately 0.5 gfl without impairing the quality of the sheep hides.
Example 4
Chrome-tanning of neat’s upper leather:
After rinsing for a short time at 20″C, smoothed neat’s skin, which had been lined, decalcified and swollen in a conventional manner, is pickled with:
Joint pickling and tanning: 100% water 20″C, 7% common salt,
duration 10 minutes, subsequent addition of
0.6% formic acid, duration 20 minutes,
0.6% sulphuric acid, duration 2 hours,
left in the bath overnight (pH 3.5 in the smoothed skin),
8% of a commercially available pulverulent chromium tanning substance,
3% Na-AI silicate in accordance with Examples A, C, D,
duration 5 hours (pH approximately 3.8 in the bath).
The tanned leather is propped up overnight, subsequently folded, neutralized, after-tanned and greased. The leathers are subsequently dried and finished in a conventional manner.
In this manner, the chromium tanning substance can be reduced from a normal 10% to less than 8% without a reduction in the quantity of the leathers, wherein the chromium content in the waste water can be reduced from approximately 8 g/l Cr2O3 to less than 1 gfl.
Example 5
Neutralisation of neat’s upper leather:
Prepared in the same manner as in Example 4.
Neutralisation:
Folded leather (pH 3.7 to 4.2)
Rinse for 10 minutes at 350C.
100% water 350C,
0.5 to 1% Na-AI silicate in accordance with Examples B, G, F, duration 30
minutes,
pH in the leather cut 4.5 to 4.7.
Further processing as in Example 4.
In this manner, one obtains a neutralising action together with a certain aftertanning effect, a grain-stabilizing effect being observed.
Example 6
Tanning of white neat’s leathers:
Pre-treatment of the smoothed hides, including decalcification and swelling, was effected in a conventional manner.
JoidVpickling and tanning: 100% water 200C,
7% common salt, duration 10 minutes, 0.zoo formic acid, 15 minutes,
0.7% sulphuric acid, 2 hours.
The smoothed skins remain in the pickling bath (pH 3.2 in the skin cut) overnight.
8% Na-Al silicate in accordance with Examples A, C, D, F in the same bath,
1.5% sulphuric acid, duration 5 hours (pH approximately 4.2 in the bath).
Subsequent propping up and folding.
After-tanning and greasing:
The folded leathers were rinsed for 10 minutes at 400C and treated in a fresh liquor with: 100% water 40″C, 6% of a neutral, mild and light-tanning, synthetic auxiliary tanning substance.
30 minutes duration.
10% of a commercially available fat-liquor which is resistant to electrolyte and
tanning substance and which is suitable for white leathers.
duration 45 minutes.
4% of a commercially available white tanning substance.
duration 30 minutes in the same liquor.
Fresh liquor.
200% water 45″C, 0.3% oxalic acid, duration 15 minutes.
Prop up leather and hang-dry.
Compared with conventional tanning with aluminium tanning substances and white tanning substances, a fuller leather having improved resistance to water, and of commercial quality, is obtained by this combination of Na-AI silicates with white tanning substances.
WHAT WE CLAIM IS:
1. A method for the production of leather from washed and cleaned hides or pelts, in which the washed and cleaned hides or pelts are subsequently contacted with a fine-particulate water-insoluble alkali metal aluminium silicate, preferably containing water, of the general formula: (cat2o)xAl2o3(sio2)+s in which Cat represents an alkali metal ion, x represents a number of from 0.7 to 1.5, y represents a number of from 0.8 to 6, which alkali metal aluminium silicate has a particle size of from 0.1 to 25, and a calcium binding capacity of 20 to 200 mg
CaO/g of anhydrous substance.
2. A method as claimed in claim I in which the hides or pelts have been subjected to a treatment to produce smooth pickled skins and said alkali metal aluminium silicate is used in at least one of the stages applied to such smooth pickled skins in the production of leather therefrom.
3. A method as claimed in claim 1 or 2, in which Cat represents a sodium ion.
4. A method as claimed in any of claims 1 to 3, in which y represents a number of from 1.3 to 4.
5. A method as claimed in any one of claims I to 4, in which the alkali metal aluminium silicate has the general formula: 0.7-1.1 Cat2O.A12O3.l.3-3.3 SiO2.
6. A method as claimed in any one of claims I to 4, in which the alkali metal aluminium silicate is produced from calcinated kaolin and has the general formula:
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (15)

**WARNING** start of CLMS field may overlap end of DESC **. Further processing as in Example 4. In this manner, one obtains a neutralising action together with a certain aftertanning effect, a grain-stabilizing effect being observed. Example 6 Tanning of white neat’s leathers: Pre-treatment of the smoothed hides, including decalcification and swelling, was effected in a conventional manner. JoidVpickling and tanning: 100% water 200C, 7% common salt, duration 10 minutes, 0.zoo formic acid, 15 minutes, 0.7% sulphuric acid, 2 hours. The smoothed skins remain in the pickling bath (pH 3.2 in the skin cut) overnight. 8% Na-Al silicate in accordance with Examples A, C, D, F in the same bath, 1.5% sulphuric acid, duration 5 hours (pH approximately 4.2 in the bath). Subsequent propping up and folding. After-tanning and greasing: The folded leathers were rinsed for 10 minutes at 400C and treated in a fresh liquor with: 100% water 40″C, 6% of a neutral, mild and light-tanning, synthetic auxiliary tanning substance. 30 minutes duration. 10% of a commercially available fat-liquor which is resistant to electrolyte and tanning substance and which is suitable for white leathers. duration 45 minutes. 4% of a commercially available white tanning substance. duration 30 minutes in the same liquor. Fresh liquor. 200% water 45″C, 0.3% oxalic acid, duration 15 minutes. Prop up leather and hang-dry. Compared with conventional tanning with aluminium tanning substances and white tanning substances, a fuller leather having improved resistance to water, and of commercial quality, is obtained by this combination of Na-AI silicates with white tanning substances. WHAT WE CLAIM IS:

1. A method for the production of leather from washed and cleaned hides or pelts, in which the washed and cleaned hides or pelts are subsequently contacted with a fine-particulate water-insoluble alkali metal aluminium silicate, preferably containing water, of the general formula: (cat2o)xAl2o3(sio2)+s in which Cat represents an alkali metal ion, x represents a number of from 0.7 to 1.5, y represents a number of from 0.8 to 6, which alkali metal aluminium silicate has a particle size of from 0.1 to 25, and a calcium binding capacity of 20 to 200 mg
CaO/g of anhydrous substance.

2. A method as claimed in claim I in which the hides or pelts have been subjected to a treatment to produce smooth pickled skins and said alkali metal aluminium silicate is used in at least one of the stages applied to such smooth pickled skins in the production of leather therefrom.

3. A method as claimed in claim 1 or 2, in which Cat represents a sodium ion.

4. A method as claimed in any of claims 1 to 3, in which y represents a number of from 1.3 to 4.

5. A method as claimed in any one of claims I to 4, in which the alkali metal aluminium silicate has the general formula: 0.7-1.1 Cat2O.A12O3.l.3-3.3 SiO2.

6. A method as claimed in any one of claims I to 4, in which the alkali metal aluminium silicate is produced from calcinated kaolin and has the general formula:
0.7-1.1 Cat2O.Al2O3. 1.3-2.4 SiO2.0.5-5.0 1120.

7. A method as claimed in any of claims 1 to 3, in which the alkali metal aluminium silicate has the general formula: 0.7-1.1 Na2O.Al2O3.2.3.3 SiO2.

8. A method as claimed in any of claims 1 to 3, in which the alkali metal aluminium silicate has the general formula: 0.7-1.1 Na2O.Al2O.3.3-5.3 SiO2.

9. A method as claimed in any one of claims I to 8, in which the alkali metal aluminium silicate has a particle size of from 1 to 12y.

10. A method as claimed in any one of claims I to 9, in which the alkali metal aluminium silicate is used for degreasing and pre-tanning of smoothed pickled skins, in admixture with anionic and/or non-ionic surfactants, in quantities of from 10 to 50 gfl of silicate and from 10 to 50 gfl of surfactant.

I I. A method as claimed in any one of claims 1 to 10, in which the alkali aluminium silicate is used, for degreasing and pre-tanning of smoothed pickled skins, in admixture with non-ionic surfactants, said non-ionic surfactants being adducts of 5 to 30 mol of ethylene oxide to higher fatty alcohols, alkylphenols, fatty acids or fatty amines having 8 to 18 carbon atoms.

12. A method as claimed in any one of claims 1 to 9, in which the alkali aluminium silicate is used for tanning and/or after-tanning of pelts and leather, in a quantity of from 5 to 80 gfl and in admixture with chrome tanning substances, synthetic and/or vegetable tanning substances.

13. A method as claimed in any one of claims 1 to 9, in which the alkali aluminium silicate is used, for neutralization of leather after tanning, in a quantity of from 2 to 20 gll.

14. A method for the production of leather substantially as hereinbefore described and with reference to any one of the Examples I to 6.

15. Leather whenever produced by a process in which a fine-particulate, water-insoluble alkali metal aluminium silicate as defined in claim 1 has been used in any stage of the process after the raw hides or pelts have been washed and cleaned.

GB19469/78A
1977-07-16
1978-05-15
Use of fine-particle water-insoluble alkali metal aluminium silicates in the production of leather

Expired

GB1603720A
(en)

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(en)

1977-07-16
1977-07-16

USE OF FINE-PIECE WATER-INSOLUBLE ALKALIAL ALUMINUM SILICATES IN THE MANUFACTURING OF LEATHER

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Use of fine-particle water-insoluble alkali metal aluminium silicates in the production of leather

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GB2368346A
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2000-07-14
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Pittards Plc
An improved process for manufacturing leather

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1986-04-28
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Commw Scient & Ind Res
Process for treating animal hides with fur

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1988-07-06
1990-01-11
Henkel Kgaa

GERB PROCESSES OF HIGH CHROME PERFORMANCE OF GERBFLOTTEN

DE10255095A1
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2002-11-26
2004-06-03
Basf Ag

Process for the manufacture of a semi-finished leather product

DE10345097A1
(en)

2003-09-26
2005-04-21
Basf Ag

Process for the production of leather and semi-finished products and formulations suitable therefor

DE102007051489A1
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2007-10-27
2009-04-30
Isa Industrial Ltd. Guangzhou Tan Tec Leather Ltd.
Classifying leather for its production, comprises measuringly detecting or computing power requirement, water consumption, carbon dioxide production and/or chemical oxygen demand of the production, and arranging production unit of leather

EP2607499A3
(en)

2013-02-14
2013-07-10
Basf Se
Method for producing leather

FR3130846A1
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2021-12-22
2023-06-23
Jacques BOBILLON

TANNING PROCESS AND TANNING COMPOSITION ALLOWING IT TO BE USED

FR3130847A1
(en)

2021-12-22
2023-06-23
Jacques BOBILLON

TANNING PROCESS AND TANNING COMPOSITION ALLOWING IT TO BE USED

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Improvements made to the tanning of hides and skins

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1942-02-25
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Du Pont
Tanning compositions and their manufacture

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1943-04-03
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Improvements in or relating to tanning compositions and processes for tanning

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1954-05-18
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Tanning of hides and skins

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Powder compsn. for treating hides – has tawing and opt. retanning agents absorbed on silica or aluminosilicate

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GB2368346A
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2000-07-14
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Pittards Plc
An improved process for manufacturing leather

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2000-07-14
2004-08-11
Pittards Plc
An improved process for manufacturing leather

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1978-07-12

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1979-03-12

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1980-05-15

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1979-08-15

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