EP0965565A1 - Water-softening tablet - Google Patents

Abstract

Tablets contg. builder substances comprise 2-100 wt.% amorphous, partly crystalline and/or crystalline layered silicates of formula Na2SixO2x+1.yH2O (I), where x=1.9-4 and y=0-20. The water content of the tablets is no more than the maximum theoretical water-binding capacity of the tablet ingredients. Also claimed are: (1) a process for producing tablets as above where the premixes intended for pressing are prepd. by mixing the individual ingredients, at least some of which are pregranulated; (2) a wash process in which at least two tablets as above, with the same or different compsn., are used in a single wash cycle, pref. a base detergent tablet and a water-softening and/or bleaching tablet; and (3) a wash process in which at least one tablet as above is used in a single wash cycle, the tablet(s) being dispensed onto the wash in the washing machine right at the start of the wash cycle. Pref. detergent tablets comprise 5-60 (esp. 10-40)wt.% (I), 0.5-98 wt.% zeolite and/or phosphate (pref. less than 30 wt.% phosphate), up to 40 wt.% anionic surfactants and/or soaps, and up to 20 wt.% nonionic surfactants. Water-softening tablets comprise 20-80 (esp. 30-60)wt.% (I), 0-80 (esp. 10-60)wt.% zeolite and/or phosphate, 0-50 (esp. 2-20) wt.% polycarboxylate, 0-15 (esp. 1-10)wt.% polymeric polycarboxylate, and 0-30 (esp. 2-15)wt.% surfactants and salts. Bleaching tablets comprise 20-80 (esp. 30-60) wt.% (I) and 20-50 (esp. 25-45) wt.% peroxy bleach. (I) may be used together with amorphous silicates of water-glass type.

Description

The invention relates to tablets, preferably tablets which are active in washing or cleaning, in particular water softener tablets or compounds in tablet form for water softeners, which contain silicate builder substances.

Tablets have a number of advantages over powdered agents, such as simple dosing and low packaging volume requirements. Problems arise, however, in that relatively high compression pressures have to be used to achieve adequate dimensional stability and fracture resistance when pressing the powdery components. Because of the high degree of compaction, such tablets often have inadequate disintegration and dissolving properties when used. Additional difficulties arise from the use of nonionic surfactants. According to the teaching of international patent application WO-A-90/02165, these problems can be solved by producing at least two granular components before pressing, the total amount of the anionic surfactants in one component and the main amount of the nonionic surfactants in the other component are included. The anionic surfactant-containing component preferably contains up to 20% by weight of anionic surfactants including the soaps, up to 30% by weight of water-containing zeolite, inorganic salts such as amorphous silicates and carbonates up to 40% by weight, polycarboxylates up to 5% by weight. , Sulfate up to 20 wt .-% and water, which is not bound to the zeolite, to a maximum of 5 wt .-%. The last three statements apply equally to the second component, which also preferably contains up to 15% by weight of nonionic surfactants, up to 20% by weight of water-containing zeolite and up to 10% by weight of soda. Other components, which contain bleaching agents and / or enzymes, for example, are also optionally available.

Tablets containing builder substances and layered sodium silicates are disclosed in European patent application EP 508 934 . This document does not describe water softening tablets.

Detergents which can be compressed into tablets are disclosed in European patent application EP 504 091 . Water softening tablets, the bulk of which is based on silicate, are neither disclosed nor suggested in this document.

Crystalline layered sodium silicates of the formula NaMSi _x O _{2x + 1} .yH ₂ O, where M is sodium or hydrogen, x is a number from 1.9 to 4 and y is a number from 0 to 20 and preferred values for x 2, 3 or 4 are, can substitute phosphates and zeolites. Such crystalline layered silicates are described, for example, in European patent application EP-A-0 164 514 . Preferred crystalline layered silicates are those in which M is sodium and x is 2 or 3. In particular, both β- and δ-sodium disilicate Na ₂ Si ₂ O ₅ .yH ₂ O are preferred, wherein β-sodium disilicate can be obtained, for example, by the method described in international patent application WO-A-91/08171 . β-sodium disilicate is commercially available under the name SKS 7®, δ-sodium disilicate is available under the name SKS 6® (commercial products from Hoechst AG, Federal Republic of Germany). These powders generally have a bulk density of less than 600 g / l and have high fines content, usually more than 30% by weight, with a particle size below 0.1 mm. Since crystalline layered silicates suffer from losses in their action as builders in spray drying detergent-containing slurries, caused by the partial destruction of their crystalline structure, they should preferably be incorporated into detergents or cleaning agents by other process methods. However, due to their high proportion of fine grains and thus their dusty structure, these powders are also unsuitable for use as an admixing component with other granular components of detergents or cleaning agents. When granulating crystalline layered sodium silicates, it should be noted that the strong abrasive properties of these silicates can damage the apparatus. This means on the one hand that the process safety is endangered and additional checks of the mixing and granulating tools are required, but also that the silicate product can be contaminated with traces of metal, in particular traces of heavy metals, due to the material abrasion. For ecological reasons, it is desirable to keep the contamination of the end product as low as possible. It is also known to the person skilled in the art that, for example, the stability of peroxy bleaching agents is adversely affected by heavy metals.

Amorphous alkali metal silicates, in particular those with a molar M ₂ O: SiO ₂ ratio of 1: 1.9 to 1: 4.0, where M preferably represents sodium and / or potassium, can generally be spray-dried, but white the person skilled in the art that the spray drying of slurries which also contain zeolite in addition to the amorphous silicates leads to negative interactions, as a result of which the exchange capacity of the zeolite is reduced and deposits which are difficult to remove can be deposited on the laundry. Granules which have a high proportion of amorphous silicates or pure spray-dried or granulated amorphous silicates, on the other hand, are hygroscopic, so that they have to be specially protected against the ingress of atmospheric moisture during storage.

On the one hand, there was the task of offering an advantageous form of offer for products develop which contain amorphous and / or crystalline silicates. It should be both the process security as well as the stability of the other ingredients, if any the offer form can be increased. In addition, the builder properties should be preserved stay. Another object of the invention was to provide builder substance-containing forms to offer those that are sufficiently soluble or dispersible for the intended purpose are.

This object was achieved in that an offer form with a relatively small specific surface was chosen, which can be produced with little water.

a) 20 bis 80 Gew.-%, vorzugsweise zu 30 bis 60 Gew.-% aus amorphen, teilkristallinen und/oder kristallinen schichtförmigen Natriumsilikaten der Formel Na₂Si_xO_2x+1·yH₂O, worin x eine Zahl von 1,9 bis 4 und y eine Zahl von 0 bis 20 ist und bevorzugte Werte für x 2, 3 oder 4 sind,

b) zu 0 bis 80 Gew.-%, vorzugsweise 5 bis 80 Gew.-% und insbesondere 10 bis 60 Gew.-% aus wasserhaltigem Zeolith und/oder Phosphat,

c) zu 0 bis 50 Gew.-%, vorzugsweise 0,5 bis 30 Gew.-% und insbesondere 2 bis 20 Gew.-% aus Polycarboxylaten,

d) zu 0 bis 15 Gew.-%, vorzugsweise zu 0,5 bis 12 Gew.-% und insbesondere zu 1 bis 10 Gew.-% aus polymeren Polycarboxylaten sowie

e) zu 0 bis 30 Gew.-%, vorzugsweise 0,5 bis 20 Gew.-% und insbesondere zu 2 bis 15 Gew.-% aus Aniontensiden, Niotensiden, alkalisch oder neutral reagierenden anorganischen Salzen oder Mischungen aus diesen besteht,

mit der Maßgabe, daß die Tablette Wasser nur in den Mengen enthält, daß das maximale theoretische Wasserbindevermögen der Inhaltsstoffe nicht überschritten wird.The invention accordingly relates to a water softening tablet containing builder substances which

a) 20 to 80% by weight, preferably 30 to 60% by weight, of amorphous, partially crystalline and / or crystalline layered sodium silicates of the formula Na ₂ Si _x O _{2x + 1} .yH ₂ O, where x is a number from 1 , 9 to 4 and y is a number from 0 to 20 and preferred values for x are 2, 3 or 4,

b) 0 to 80% by weight, preferably 5 to 80% by weight and in particular 10 to 60% by weight, of water-containing zeolite and / or phosphate,

c) 0 to 50% by weight, preferably 0.5 to 30% by weight and in particular 2 to 20% by weight, of polycarboxylates,

d) 0 to 15% by weight, preferably 0.5 to 12% by weight and in particular 1 to 10% by weight of polymeric polycarboxylates and

e) 0 to 30% by weight, preferably 0.5 to 20% by weight and in particular 2 to 15% by weight, of anionic surfactants, nonionic surfactants, alkaline or neutral reacting inorganic salts or mixtures of these,

with the proviso that the tablet contains water only in the amounts that the maximum theoretical water binding capacity of the ingredients is not exceeded.

The maximum theoretical water binding capacity can be based on the one described below Be determined. Some components of the tablets form an accepted one Storage temperature of 15 to 45 ° C stable hydrates. This applies e.g. for zeolite. Components like sodium sulfate and polymeric polycarboxylates, on the other hand, are considered anhydrous Substances are calculated, although it is known that these are usually in granules in hydrated form. Crystalline layered sodium disilicates are also used calculated anhydrous, while amorphous sodium silicates, for example, have a water content can have up to about 22% by weight. The sum of the crystal water shares from the stable hydrates gives the maximum theoretical water content of the invention Tablet. It may even be preferred that the tablet be in an over-dried form is present, i.e. contains less water than the maximum theoretical water binding capacity corresponds to or taken up as stable by the tablet ingredients can be.

The tablets can be produced in such a way that the amorphous, partially crystalline and / or crystalline layered sodium silicates and, if appropriate, all other constituents are mixed with one another in a mixer and the mixture by means of conventional tablet presses, for example eccentric presses, hydraulic presses or rotary presses with pressures in the range of 10 ⁵ to 3 · 10 ⁷ Pa (1 to 300 bar), advantageously in the range from about 5 · 10 ⁵ to 2 · 10 ⁷ Pa (5 to 200 bar) and in particular between 10 ⁶ to 1.5 · 10 ⁷ Pa (10 and 150 bar) pressed. The compression is preferably carried out without the addition of water. In a preferred embodiment of the invention, however, the premixes intended for compression are produced by mixing the individual ingredients, which are present at least in part in pre-assembled form as a granular compound. These include, for example, roller-compacted, crystalline, layered or amorphous sodium disilicates, which have optionally been impregnated with liquid to wax-like components, for example nonionic surfactants. In particular, this enables water-free pre-assembly, which is particularly advantageous. In this way, break-resistant tablets with good breaking strength, which dissolve sufficiently quickly under application conditions, are obtained without any problems. The pressing conditions in the respective case are usually to be optimized for the setting of the desired solubility of the tablet with sufficient strength or hardness of the tablet. It applies in a manner known per se that higher compression pressures reduce the solubility of the tablet. Preferred tablets have a breaking strength of at least 55 N and in particular at least 60 N. Tablets with brewing strengths above 150 N are also possible.

Practically all sensible, manageable design forms come in as the spatial form Consider, as long as they meet the requirements, that the contact to the tabletting apparatus is relatively small during the manufacturing process. Cylindrical ones are preferred Designs with oval or circular cross-section of those given below Art. A tablet produced in this way preferably has a weight of 10 to 120 g, in particular from 20 to 100 g, the diameter of the tablets being customary is less than 100 mm. Preferred detergent tablets have a diameter of maximum 80 mm and in particular from 30 to 80 mm. However, it is also possible and especially preferred with regard to improved solubilities, several, ie use at least 2 tablets with the same or different composition. These tablets preferably have a weight of 10 to 40 g, with a diameter from 20 to 50 mm are preferred. The diameter / height ratio of the tablets should be be optimized so that the least possible abrasion on the vertical walls the tabletting apparatus (high diameter / low height) with sufficient Stability and a not too large surface (small diameter / high height) guaranteed is. Preferred diameter / height ratios of the cylindrical compacts are approximately 0.5: 1 to 10: 1, in particular 1: 1 to 8: 1.

The content of the tablets in amorphous, partially crystalline and / or crystalline layered Sodium silicates can vary in a wide range. In the invention Water softening tablets have an amorphous, partially crystalline and / or crystalline content layered sodium silicates at 20 to 80% by weight and in particular at 30 up to 60% by weight.

Of the crystalline layered sodium silicates, the low-water to anhydrous disilicates are particularly preferred. The preferred amorphous silicates primarily include the known spray-dried water glasses with a Na ₂ O: SiO ₂ weight ratio of 1: 1.9 to 1: 3.35. A preferred embodiment of silicates are silicate-carbonate compounds, for example those according to European patent applications EP-A-0 488 868 and EP-A-0 561 565. Such compounds are sold under the name Nabion 15® (commercial product from Rôhne- Poulenc) commercially available. A particularly preferred embodiment of silicates is, however, those X-ray amorphous silicates as described in the older German patent application DE 44 00 024 . Therefore, tablets are preferred which contain either crystalline layered sodium silicates of the specified type or such X-ray amorphous silicates, or tablets which contain crystalline layered sodium silicates and X-ray amorphous silicates in a weight ratio of 10: 1 to 1:10. Particularly preferred tablets are free of conventional amorphous silicates of the water glass type or contain these amorphous silicates of the water glass type only in combination with crystalline layered sodium silicates and / or X-ray amorphous silicates, the content of amorphous silicates of the water glass type advantageously being 20% by weight. -% and in particular 15 wt .-%, each based on the total amount of silicates present in the tablet, does not exceed.

The tablets can have conventional tabletting aids and disintegrants, if these in the group of (polymeric) polycarboxylates [ingredients c) or d)] or alkaline or neutral reacting inorganic salts [ingredient e)].

Auxiliaries which disintegrate or dissolve are regarded as disintegrants influence positively in the aqueous application phase. These disintegrants can be more inorganic and / or organic in nature. Typical inorganic-based explosives are, for example, swellable layered silicates such as bentonites. Organic explosives can be natural substances or their derivatives based on starch or cellulose. Here can in particular the usual ingredients of detergents or cleaning agents such as Salts of polymeric polyacrylates or polymethacrylates, for example those with a low molecular weight between 1000 and 5000 can be called.

Other examples are acetates or percarbonates. The latter are preferably in tablets containing bleach or used directly in the bleaching tablets. It is usual, to use such disintegrants in amounts of up to about 15% by weight, based on the tablet. Because of the use of water-soluble silicates, it is sufficient for the inventive ones Tablets in most cases, the disintegrant in amounts far below 10 wt .-%, preferably in amounts of up to 5 wt .-% and in particular still use underneath. When using poly (meth) acrylates usually lead Amounts around 1% by weight for very good results.

In contrast to the explosives, tabletting aids ensure better cohesion of the individual powdery or granular components and thus contribute to the stability of the tablet. However, there are quite a number of explosives that also serve as tableting aids or binders. These include, for example liquid to pasty nonionic surfactants at processing temperature.

The explosives and tableting aids are preferably in dry form or in a used in nonionic surfactant or suspended form. An aqueous form of use is less preferred because water is only added in quantities during the process may be; that the maximum theoretical water binding capacity of the tablet ingredients is not exceeded. In a particularly preferred embodiment of the The invention is therefore not an ingredient in the form of an aqueous solution or suspension used and the pressing is carried out without the addition of water.

In a preferred embodiment of the invention, the tablets contain in particular other common builder substances. These include inorganic builder substances such as zeolite and / or phosphates or organic builders such as polycarboxylates and / or polymeric polycarboxylates.

In the water softening tablets according to the invention, 0 to 80% by weight is preferred 5 to 80 wt .-% and in particular 10 to 60 wt .-% of water-containing zeolite and / or phosphate present. Tablets are preferred in which the content of Phosphates preferably to a maximum of 50% by weight and in particular to a maximum of 30 % By weight is limited.

The used, fine crystalline, synthetic and bound water containing zeolite is preferably zeolite NaA in detergent quality. However, zeolite is also suitable NaX as well as mixtures of A, X or P. The zeolite can either be spray dried Powder or as a granular compound, for example up to about 50% by weight other ingredients such as nonionic surfactants, cellulose ethers and / or polymeric polycarboxylates contains, are used. Suitable powdered zeolites have a average particle size of less than 10 µm (volume distribution; measurement method: Coulter Counter) and preferably contain 18 to 22% by weight, in particular 20 to 22% by weight bound water.

In a further preferred embodiment of the invention contain the invention Water softening tablets preferably contain 0 to 50% by weight, in particular 0.5 to 30% by weight and advantageously 2 to 20% by weight of polycarboxylates and additionally preferably 0 to 15% by weight, in particular 0.5 to 12% by weight and advantageously 1 to 10% by weight of polymeric polycarboxylates. To the polycarboxylic acids or the polycarboxylates include in particular those used in the form of their sodium salts Polycarboxylic acids such as citric acid, adipic acid, succinic acid, glutaric acid, Tartaric acid, sugar acids and mixtures of these. Suitable polymeric polycarboxylates are for example the sodium salts of polyacrylic acid or polymethacrylic acid, for example those with a molecular weight of 800 to 150,000 (on acid based). Suitable copolymeric polycarboxylates are, in particular, those of acrylic acid with methacrylic acid and acrylic acid or methacrylic acid with maleic acid. As special copolymers of acrylic acid with maleic acid have proven suitable, the 50 to Contain 90 wt .-% acrylic acid and 50 to 10 wt .-% maleic acid. Your molecular weight, based on free acids, is generally 5000 to 200000, preferably 10,000 to 120,000 and in particular 50,000 to 100,000. Particularly preferred also terpolymeric polycarboxylates, for example those which are salts of the monomers Acrylic acid and maleic acid as well as vinyl alcohol or vinyl alcohol derivatives (P 43 00 772.4) or the monomeric salts of acrylic acid and 2-alkylallylsulfonic acid and Contain sugar derivatives (P 42 21 381.9).

The (co) polymeric polycarboxylates are preferably used either as a powder or as a granular compound. Suitable granular compounds are, for example, those which are known from international patent application WO-A-92/13937 .

Other suitable builder systems are oxidation products of carboxyl-containing polyglucosans and / or their water-soluble salts, as are described, for example, in international patent application WO-A-93/08251 or their preparation, for example, in international patent application WO-A-93/16110 or the older German one Patent application DE 43 30 393 is described.

The water softening tablets according to the invention consist of 0 to 30% by weight, preferably but 0.5 to 20% by weight, and particularly 2 to 15% by weight, from the following mentioned anionic surfactants, nonionic surfactants, alkaline or neutral reacting inorganic Salts or mixtures thereof.

Preferred surfactants of the sulfonate type are C ₉ -C ₁₃ alkylbenzenesulfonates, olefin sulfonates, ie mixtures of alkene and hydroxyalkanesulfonates and disulfonates such as are obtained, for example, from C ₁₂ -C ₁₈ monoolefins with a terminal or internal double bond by sulfonating with gaseous Sulfur trioxide and subsequent alkaline or acidic hydrolysis of the sulfonation products is considered.

Also suitable are alkanesulfonates obtained from C ₁₂ -C ₁₈ alkanes, for example by sulfochlorination or sulfoxidation with subsequent hydrolysis or neutralization.

Also suitable are the esters of α-sulfo fatty acids (ester sulfonates), e.g. the α-sulfonated Methyl ester of hydrogenated coconut, palm kernel or tallow fatty acids.

Other suitable anionic surfactants are sulfonated fatty acid glycerol esters. Among fatty acid glycerol esters the mono-, di- and triesters and their mixtures are to be understood as they are the preparation by esterification by a monoglycerol with 1 to 3 moles of fatty acid or obtained in the transesterification of triglycerides with 0.3 to 2 mol of glycerol. Preferred sulfated fatty acid glycerol esters are the sulfonation products of saturated fatty acids with 6 to 22 carbon atoms, for example caproic acid, caprylic acid, capric acid, Myristic acid, lauric acid, palmitic acid, stearic acid or behenic acid. Go fats and oils, i.e. natural mixtures of different fatty acid glycerol esters off, it is necessary to in the feed products before sulfonation to become saturated with hydrogen to a large extent, i.e. on iodine numbers smaller 5, advantageously less than 2 harden. Typical examples are suitable feedstocks Palm oil, palm kernel oil, palm stearin, olive oil, rapeseed oil, coriander oil, sunflower oil, cottonseed oil, Peanut oil, linseed oil, lard oil or lard. Because of their high natural Proportion of saturated fatty acids, however, it has proven to be particularly advantageous from coconut oil, palm kernel oil or beef tallow. The sulfation of the saturated Fatty acids with 6 to 22 carbon atoms or mixtures of fatty acid glycerol esters with iodine numbers less than 5, the fatty acids with 6 to 22 carbon atoms contain, is preferably carried out by reaction with gaseous sulfur trioxide and subsequent neutralization with aqueous bases, as described in the international patent application WO-A-91/09009 is indicated.

Preferred alk (en) yl sulfates are the sulfuric acid half-esters of the C ₁₂ -C ₁₈ fatty alcohols, for example from coconut oil alcohol, tallow fatty alcohol, lauryl, myristyl, cetyl or stearyl alcohol or the C ₁₀ -C ₂₀ oxo alcohols and those half-esters of secondary alcohols of this chain length . Also preferred are alk (en) yl sulfates of the chain length mentioned which contain a synthetic, straight-chain alkyl radical prepared on a petrochemical basis and which have a degradation behavior analogous to that of the adequate compounds based on oleochemical raw materials. C ₁₆ -C ₁₈ alk (en) yl sulfates are particularly preferred from the point of view of washing technology. It can also be particularly advantageous, and particularly advantageous for machine washing agents, to use C ₁₆ -C ₁₈ alk (en) yl sulfates in combination with lower melting anionic surfactants and in particular with those anionic surfactants which have a lower Krafft point and relatively low ones Washing temperatures of, for example, room temperature to 40 ° C. show a low tendency to crystallize. In a preferred embodiment of the invention, the compositions therefore contain mixtures of short-chain and long-chain fatty alkyl sulfates, preferably mixtures of C ₁₂ -C ₁₄ fatty alkyl sulfates or C ₁₂ -C ₁₈ fatty alkyl sulfates with C ₁₆ -C ₁₈ fatty alkyl sulfates and in particular C ₁₂ -C ₁₆ -Fatty alkyl sulfates with C ₁₆ -C ₁₈ fatty alkyl sulfates. In a further preferred embodiment of the invention, however, not only saturated alkyl sulfates but also unsaturated alkenyl sulfates with an alkenyl chain length of preferably C ₁₆ to C ₂₂ are used. Mixtures of saturated sulfonated fatty alcohols predominantly consisting of C ₁₆ and unsaturated sulfated fatty alcohols predominantly consisting of C ₁₈ are particularly preferred, for example those derived from solid or liquid HD-Ocenol ^(R) fatty alcohol mixtures (commercial product of the applicant) . Weight ratios of alkyl sulfates to alkenyl sulfates from 10: 1 to 1: 2 and in particular from about 5: 1 to 1: 1 are preferred.

The sulfuric acid monoesters of the straight-chain or branched C ₇ -C ₂₁ alcohols ethoxylated with 1 to 6 mol of ethylene oxide, such as 2-methyl-branched C ₉ -C ₁₁ alcohols with an average of 3.5 mol of ethylene oxide (EO) or C ₁₂ - C ₁₈ fatty alcohols with 2 to 4 EO are suitable. Because of their high foaming behavior, they are used in detergents only in relatively small amounts, for example in amounts of 1 to 5% by weight.

Preferred anionic surfactants are also the salts of alkylsulfosuccinic acid, which are also referred to as sulfosuccinates or as sulfosuccinic acid esters and which represent monoesters and / or diesters of sulfosuccinic acid with alcohols, preferably fatty alcohols and in particular ethoxylated fatty alcohols. Preferred sulfosuccinates contain C ₈ to C ₁₈ fatty alcohol residues or mixtures thereof. Particularly preferred sulfosuccinates contain a fatty alcohol residue, which is derived from ethoxylated fatty alcohols, which, when considered to be nonionic surfactants (description see below). Again, sulfosuccinates whose fatty alcohol residues are derived from ethoxylated fatty alcohols with a narrow homolog distribution are particularly preferred. It is also possible to use alk (en) ylsuccinic acid with preferably 8 to 18 carbon atoms in the alk (en) yl chain or salts thereof.

Preferred anionic surfactant mixtures contain combinations of alk (en) yl sulfates, in particular Mixtures of saturated and unsaturated fatty alk (en) yl sulfates, and alkylbenzenesulfonates, sulfonated fatty acid glycerol esters and / or α-sulfofatty acid esters. Especially Mixtures which contain alk (en) yl sulfates as anionic surfactants are preferred and alkylbenzenesulfonates, alk (en) ylsulfates and α-sulfofatty acid methyl esters and / or sulfated Contain fatty acid glycerol esters.

Other suitable anionic surfactants are, in particular, soaps, preferably in amounts of 0.1 to 5% by weight. Suitable are, for example, saturated fatty acid soaps, such as the salts of lauric acid, myristic acid, palmitic acid or stearic acid, and in particular soap mixtures derived from natural fatty acids, for example coconut, palm kernel or tallow fatty acids. In particular, those soap mixtures are preferred which are composed of 50 to 100% by weight of saturated C ₁₂ -C ₂₄ fatty acid soaps and 0 to 50% by weight of oleic acid soap.

The anionic surfactants and soaps can be in the form of their sodium, potassium or ammonium salts and as soluble salts of organic bases, such as mono-, di- or triethanolamine, available. The anionic surfactants are preferably in the form of their sodium or Potassium salts, especially in the form of the sodium salts.

The nonionic surfactants used are preferably alkoxylated, advantageously ethoxylated, in particular primary alcohols having preferably 8 to 18 carbon atoms and an average of 1 to 12 moles of ethylene oxide (EO) per mole of alcohol, in which the alcohol radical can be linear or preferably methyl-branched in the 2-position or may contain linear and methyl-branched radicals in the mixture, as are usually present in oxo alcohol radicals. However, alcohol ethoxylates with linear residues of alcohols of native origin with 12 to 18 carbon atoms, for example from coconut, palm, tallow fat or oleyl alcohol, and an average of 2 to 8 EO per mole of alcohol are particularly preferred. The preferred ethoxylated alcohols include, for example, C ₁₂ -C ₁₄ alcohols with 3 EO or 4 EO, C ₉ -C ₁₁ alcohol with 7 EO, C ₁₃ -C ₁₅ alcohols with 3 EO, 5 EO, 7 EO or 8 EO, C ₁₂ -C ₁₈ alcohols with 3 EO, 5 EO or 7 EO and mixtures thereof, such as mixtures of C ₁₂ -C ₁₄ alcohol with 3 EO and C ₁₂ -C ₁₈ alcohol with 5 EO. The degrees of ethoxylation given represent statistical averages, which can be an integer or a fraction for a specific product. Preferred alcohol ethoxylates have a narrow homolog distribution (narrow range ethoxylates, NRE). In addition to these nonionic surfactants, fatty alcohols with more than 12 EO, for example those up to about 80 EO, can also be used. Examples include tallow fatty alcohol with 14 EO, 25 EO, 30 EO or 40 EO.

In addition, alkyl glycosides of the general formula RO (G) _x can also be used as further nonionic surfactants, in which R denotes a primary straight-chain or methyl-branched, in particular methyl-branched aliphatic radical having 8 to 22, preferably 12 to 18, C atoms and G is the symbol which stands for a glycose unit with 5 or 6 carbon atoms, preferably for glucose. The degree of oligomerization x, which indicates the distribution of monoglycosides and oligoglycosides, is any number between 1 and 10; x is preferably 1.2 to 1.4.

Also nonionic surfactants of the amine oxide type, for example N-cocoalkyl-N, N-dimethylamine oxide and N-tallow alkyl-N, N-dihydroxyethylamine oxide, and the fatty acid alkanolamides can be suitable. The amount of these nonionic surfactants is preferably not more than that of ethoxylated fatty alcohols, especially not more than half of it.

in der R²CO für einen aliphatischen Acylrest mit 6 bis 22 Kohlenstoffatomen, R³ für Wasserstoff, einen Alkyl- oder Hydroxyalkylrest mit 1 bis 4 Kohlenstoffatomen und [Z] für einen linearen oder verzweigten Polyhydroxyalkylrest mit 3 bis 10 Kohlenstoffatomen und 3 bis 10 Hydroxylgruppen steht.Other suitable surfactants are polyhydroxy fatty acid amides of the formula (I),

in the R ² CO for an aliphatic acyl radical having 6 to 22 carbon atoms, R ³ for hydrogen, an alkyl or hydroxyalkyl radical with 1 to 4 carbon atoms and [Z] for a linear or branched polyhydroxyalkyl radical with 3 to 10 carbon atoms and 3 to 10 hydroxyl groups stands.

The tablets contain the nonionic surfactants in a preferred embodiment in amounts up to 20% by weight.

Tools coated with hard plastic, as well as uncoated, supplied tablets with smooth surfaces, so that in most cases on a coating of the Stamp with soft plastic could be dispensed with. However, it is preferred that the pressing tools are made of high-strength material.

Other preferred ingredients are alkaline inorganic salts in water, which are preferably up to 15% by weight in the tablets. To these inorganic alkaline reacting salts include in particular bicarbonates, or carbonates Mixtures of these; alkali carbonate and especially sodium carbonate are preferred used.

Furthermore, the tablets can contain up to 20% by weight of inorganic substances which are neutral in water Contain salts, preferably sulfates and chlorides, especially in the form of their sodium and / or calcium salts. Their content in the tablets is preferably up to about 20% by weight.

Peroxy bleach can be used as a further important ingredient of tablets be mentioned as alkaline or neutral reacting inorganic salts.

Among the compounds which serve as bleaching agents and supply H ₂ O ₂ in water, sodium perborate tetrahydrate and sodium perborate monohydrate are of particular importance. Further bleaching agents which can be used are, for example, sodium percarbonate, peroxypyrophosphates, citrate perhydrates and H ₂ O ₂ -supplying peracid salts or peracids. Peroxy bleaching agents which deliver 10 to 20% active oxygen per mole of component are particularly preferred.

The water softening tablets according to the invention can consist of several sub-components, as described in patent application WO-A-90/02165 . It is therefore preferred that the tablets are produced by mixing at least 2 previously prepared granular powder components and then compressing this mixture, the total amount of the anionic surfactants in one component and 75 to 100% by weight in the other component. % of the total amount of nonionic surfactants is included if these substances are used. Other sub-components can also be used to manufacture the tablets, these can contain bleaching agents in particular.

But it is also possible that the various components do not become one Tablet is compressed, but that tablets are obtained which have several layers, thus have at least 2 layers. It is also possible that these different Layers have different dissolving speeds. This can be advantageous application properties of the tablets result. If, for example, components are contained in the tablets, which mutually negatively influence each other it is possible to integrate the one component in the quick-dissolving layer and the incorporate other components into a slower soluble layer so that the first Component has already reacted when the second goes into solution. In another preferred Embodiment of the invention, a tablet consists of at least three Layers, i.e. two outer and at least one inner layer, at least in One of the inner layers contains a peroxy bleach, the two outer ones However, layers are free of peroxy bleach. Such multilayer tablets have the advantage that they not only have a dispensing chamber or a metering device, which is added to the wash liquor can be used; much more in such cases it is also possible to put the tablet in direct contact with the textiles the machine without bleaching and the like would be feared.

Examples

The tablets of the following examples were prepared in such a way that the corresponding ones were first used Components mixed and then in a hydraulically working Press (company Kürschner, Federal Republic of Germany) for press prints in the range of about 10 to 150 bar were produced.

A tablet was produced from a mixture which contained 5.7% by weight sodium carbonate, 67% by weight SKS-6®, 1% by weight methylhydroxypropyl cellulose, 16% by weight trisodium citrate dihydrate, 8% by weight a terpolymeric salt of acrylic acid, maleic acid and vinyl alcohol, prepared in accordance with the teaching of German patent application DE 43 00 772 and subsequent spray drying of a 38% by weight aqueous solution, 0.72% by weight water, which is made from the raw materials used and not additionally was added, and 0.5 wt .-% sodium sulfate and the rest contained other salts from the raw materials. The tablet had a diameter of 23 mm, a height of 10 mm and a weight of 20 g.

Claims (10)

Water softening tablet containing builder substances, characterized in that they too a) 20 to 80% by weight, preferably 30 to 60% by weight, of amorphous, partially crystalline and / or crystalline layered sodium silicates of the formula Na ₂ Si _x O _{2x + 1} .yH ₂ O, where x is a number from 1 , 9 to 4 and y is a number from 0 to 20 and preferred values for x are 2, 3 or 4, b) 0 to 80% by weight, preferably 5 to 80% by weight and in particular 10 to 60% by weight, of water-containing zeolite and / or phosphate, c) 0 to 50% by weight, preferably 0.5 to 30% by weight and in particular 2 to 20% by weight, of polycarboxylates, d) 0 to 15% by weight, preferably 0.5 to 12% by weight and in particular 1 to 10% by weight of polymeric polycarboxylates and e) 0 to 30% by weight, preferably 0.5 to 20% by weight and in particular 2 to 15% by weight, of anionic surfactants, nonionic surfactants, alkaline or neutral reacting inorganic salts or mixtures of these, with the proviso that the tablet contains water only in the amounts that the maximum theoretical water binding capacity of the ingredients is not exceeded. Tablet according to claim 1, characterized in that it is either crystalline layered sodium silicates or X-ray amorphous silicates or that they are crystalline layered sodium silicates and X-ray amorphous silicates in weight ratio from 10: 1 to 1:10 included. Tablet according to claim 1 or 2, characterized in that it is free from the usual amorphous silicates of the water glass type. Tablet according to claim 1 or 2, characterized in that it is amorphous silicates of the water glass type in combination with crystalline layered sodium silicates and / or X-ray amorphous silicates, the content of amorphous silicates of the water glass type, preferably 20% by weight and in particular 15% by weight, based on the total amount of silicates present in the tablet, not exceeds. Tablet according to one of claims 1 to 4, characterized in that it is over-dried Form is present. Tablet according to one of claims 1 to 5, characterized in that the content of phosphates preferably to a maximum of 50% by weight and in particular to a maximum 30 wt .-% is limited. Process for the preparation of water softening tablets according to one of the claims 1 to 6, characterized in that the premixes provided for compression by mixing the individual ingredients, which are at least partially pre-assembled Form are present as a granular compound. A method according to claim 7, characterized in that the pressing without addition of water. A method according to claim 7 or 8, characterized in that roller compacted Crystalline layered sodium disilicates, which may be mixed with liquid wax-like components, for example impregnated with nonionic surfactants are used as a granular compound. Method according to one of claims 7 to 9, characterized in that before the Pressing at least 2 powdery to granular compounds are produced, the first of which is the total amount of anionic surfactants and the second 75 contains up to 100 wt .-% of the total amount of nonionic surfactants.