CA2324070A1 - Detergent tablets with improved abrasion resistance - Google Patents

Abstract

Compositions containing 60 to 95% by weight of anionic surfactants, 5 to 40% by weight of hydrotropes and 0 to 35% by weight of carrier material(s) provide detergent tablets with increased resistance to impact and friction.

Description

DETERGENT TABLETS WITH IMPROVED ABRASION RESISTANCE
Field of the Invention This invention relates generally to compact shaped bodies having detersive properties. Detersive shaped bodies include, for example, laundry detergent tablets, tablets for dishwashing machines or for cleaning hard surfaces, bleach tablets for use in washing or dishwashing machines, water softening tablets or stain remover tablets. More particularly, the present invention relates to laundry detergent tablets which are used for washing laundry in domestic washing machines and which are referred to in short as detergent tablets.
Background of the Invention Detergent tablets are widely described in the prior-art literature and are enjoying increasing popularity among consumers because they are easy to dose.
Tabletted detergents have a number of advantages over powder-form detergents:
they are easier to dose and handle and, by virtue of their compact structure, have advantages in regard to storage and transportation. As a result, detergent shaped bodies are also comprehensively described in the patent literature. One problem which repeatedly arises in the use of detergent tablets is the inadequate disintegrating and dissolving rate of the tablets under in-use conditions.
Since sufficiently stable, i.e. dimensionally stable and fracture-resistant, tablets can only be produced by applying relatively high pressures, the ingredients of the tablet are heavily compacted so that disintegration of the tablet in the wash liquor is delayed which results in excessively slow release of the active substances in the washing process. The delayed disintegration of the tablets has the further disadvantage that typical detergent tablets cannot be flushed into the washing process from the dispensing compartment of domestic washing machines because the tablets do not disintegrate sufficiently quickly into secondary particles which are small enough to be flushed from the dispensing compartment into the drum of the washing machine. Another problem which occurs with detergent tablets in particular lies in the friability of the tablets and their often inadequate resistance to abrasion. Thus, although sufficiently fracture-resistant, i.e. hard, detergent tablets can be produced, they are often not strong enough to withstand the loads encountered during packaging, transportation and handling, i.e. impact and friction effects, so that broken edges and signs of abrasion spoil the appearance of the tablet or even lead to the complete destruction of its structure.
Many solutions have been developed in the prior art to overcome the dichotomy between hardness, i.e. transportation and handling stability, and easy disintegration of the tablets. One solution known in particular from the field of pharmacy and extended to detergent tablets is to incorporate certain disintegration aids which facilitate the access of water and which swell on contact with water and effervesce or otherwise disintegrate. Other solutions proposed in the patent literature are based on the compression of premixes of certain particle sizes, the separation of individual ingredients from certain other ingredients and the coating of individual ingredients or the entire tablet with binders.
European patent application EP 711 828 (Unilever) describes detergent tablets containing surfactant(s), builders) and a polymer which acts as a binding and disintegration aid. The binders disclosed in this document are said to be solid at room temperature and to be added to the premix to be compressed in the form of a melt. Preferred binders are relatively high molecular weight polyethylene glycols.
The use of slid polyethylene glycols is also described in German patent application DE 197 09 411.2 (Henkel). This document teaches synergistic effects between the ethylene glycols and overdried amorphous silicates.
Solutions to the problem of the friability or abrasion resistance of detergent tablets are disclosed in the prior art, for example in hitherto unpublished German patent application DE 198 41 146.4 (Henkel KGaA). This document teaches adding 0.25 to 10% by weight, based on tablet weight, of one or more non-surfactant, water-soluble liquid binders to the premix to be tabletted.
Although the addition of liquids to tabletting premixes is advantageous because they can be both easily and precisely dosed, it does lead to technical problems and unwanted side effects. On the one hand, tabletting premixes are normally prepared from various powders and granules, so that addition points for liquids involve additional capital investment in plant; on the other hand, a liquid binder sprayed onto the premix is distributed throughout the premix so that larger V

quantities of binder are required. Another problem is that the liquids applied to the premix tend to "exude" during the tabletting process, resulting in caking of the premix on the punches used for tabletting. It has also been found that liquids added to the premix can adversely affect the shelf life of the tablets. In particular, their disintegration properties deteriorate significantly at relatively high storage temperatures with the result that the tablets may no longer disintegrate in a sufficiently short time. If, therefore, the tablets are added from the dispensing compartment, large quantities of detergent remain undissolved after the final rinse cycle.
Summary of the Invention Now, the problem addressed by the present invention was to provide tablets which, for predetermined hardness, would be distinguished by short disintegration times which and, accordingly, could even be flushed into the washing process from the dispensing compartment of commercially available washing machines. In addition to meeting these requirements, the tablets would have increased resistance to impact and friction, i.e. would show improved, i.e.
reduced, friability and would exhibit reduced abrasion behavior. In contrast to the solutions proposed in the prior art, these advantageous tablet properties would be able to be achieved by addition of solids so that dosing, storage and tabletting problems would be minimized.
It has now been found that the addition of special compounds of anionic surfactant(s), hydrotrope(s) and optionally carriers to premixes for detergent tablets leads to tablets which are distinctly more abrasion-resistant and considerably less friable than the hitherto known tablets. The use of the additives mentioned has little or no effect on the fracture hardness. Tabletting problems are also avoided by this addition.
In a first embodiment, the present invention relates to an additive for detergent tablets which may be added to the tablettable premixes in order to improve the physical properties of the tablets. Accordingly, the present invention relates firstly to a composition containing - based on the weight of the additive -a) 60 to 95% by weight of anionic surfactant(s), b) 5 to 40% by weight of hydrotrope(s), c) 0 to 35% by weight of carrier material(s).
The composition according to the invention contains one or more anionic surfactants) as first key constituents. Preferred compositions contain 65 to 90%
by weight, preferably 70 to 85% by weight and more preferably 75 to 80% by weight, based on the weight of the compound, of anionic surfactant(s).
Suitable anionic surfactants are, for example, those of the sulfonate and sulfate type. Suitable surfactants of the sulfonate type are preferably C9_~3 alkyl benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and hydroxyalkane sulfonates, and the disulfonates obtained, for example, from C~2_~$
monoolefins with an internal or terminal double bond by sulfonation with gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of the sulfonation products.
Other suitable surfactants of the sulfonate type are the alkane sulfonates obtained from C~2_~$ alkanes, for example by sulfochlorination or sulfoxidation and subsequent hydrolysis or neutralization. The esters of a-sulfofatty acids (ester sulfonates), for example the a-sulfonated methyl esters of hydrogenated coconut, palm kernel or tallow acids, are also suitable.
Detailed Description of the Invention Other suitable anionic surfactants are sulfonated fatty acid glycerol esters.
Fatty acid glycerol esters in the context of the present invention are the monoesters, diesters and triesters and mixtures thereof which are obtained where production is carried out by esterification of a monoglycerol with 1 to moles of fatty acid or in the transesterification of triglycerides with 0.3 to 2 moles of glycerol. Preferred sulfonated fatty acid glycerol esters are the sulfonation products of saturated fatty acids containing 6 to 22 carbon atoms, for example caproic acid, caprylic acid, capric acid, myristic acid, lauric acid, palmitic acid, stearic acid or behenic acid.
Preferred alk(en)yl sulfates are the alkali metal salts and, in particular, the sodium salts of the sulfuric acid semiesters of C,2_~$ fatty alcohols, for example cocofatty alcohol, tallow fatty alcohol, lauryl, myristyl, cetyl or stearyl alcohol, or Coo-zo oxoalcohols and the corresponding semiesters of secondary alcohols with the same chain length. Other preferred alk(en)yl sulfates are those with the chain length mentioned which contain a synthetic, linear alkyl chain based on a petrochemical and which are similar in their degradation behavior to the corresponding compounds based on oleochemical raw materials. C~2_~6 alkyl sulfates, C~2_~5 alkyl sulfates and C~4_~5 alkyl sulfates are preferred from the point of view of washing technology. Other suitable anionic surfactants are 2,3-alkyl 5 sulfates which may be produced, for example, in accordance with US 3,234,258 or US 5,075,041 and which are commercially obtainable as products of the Shell Oil Company under the name of DAN~.
The sulfuric acid monoesters of linear or branched C~_2~ alcohols ethoxylated with 1 to 6 moles of ethylene oxide, such as 2-methyl-branched C9_»
alcohols containing on average 3.5 moles of ethylene oxide (EO) or C~2_~a fatty alcohols containing 1 to 4 EO, are also suitable. In view of their high foaming capacity, they are only used in relatively small quantities, for example in quantities of 1 to 5% by weight, in dishwashing detergents.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic acid which are also known as sulfosuccinates or as sulfosuccinic acid esters and which represent monoesters and/or diesters of sulfosuccinic acid with alcohols, preferably fatty alcohols and, more particularly, ethoxylated fatty alcohols.
Preferred sulfosuccinates contain C8_~$ fatty alcohol residues or mixtures thereof.
Particularly preferred sulfosuccinates contain a fatty alcohol residue derived from ethoxylated fatty alcohols which, considered in isolation, represent nonionic surfactants (for a description, see below). Of these sulfosuccinates, those of which the fatty alcohol residues are derived from narrow-range ethoxylated fatty alcohols are particularly preferred. Alk(en)yl succinic acid preferably containing 8 to 18 carbon atoms in the alk(en)yl chain or salts thereof may also be used.
Other suitable anionic surfactants are, in particular, soaps. Suitable soaps are saturated fatty acid soaps, such as the salts of lauric acid, myristic acid, palmitic acid, stearic acid, hydrogenated erucic acid and behenic acid, and soap mixtures derived in particular from natural fatty acids, for example coconut, palm kernel or tallow acids.
The anionic surfactants, including the soaps, may be present in the form of their sodium, potassium or ammonium salts and as soluble salts of organic bases, such as mono-, di- or triethanolamine. The anionic surfactants are preferably present in the form of their sodium or potassium salts and, more preferably, in the form of their sodium salts.
Preferred compositions contain one or more surfactants from the groups of fatty alcohol sulfates, alkyl benzenesulfonates and/or the soaps as anionic surfactant(s).
Particularly preferred compositions according to the invention are characterized in that they contain the alkali metal salts and preferably the sodium salts of C9_~3 alkyl benzenesulfonic acids as anionic surfactant.
Alkyl benzenesulfonates as high-performance anionic surfactants have been known since the nineteen thirties. At that time, alkyl benzenes were produced by monochlorination of Kogasin fractions and subsequent Friedel Crafts alkylation, sulfonated with oleum and neutralized with sodium hydroxide.
At the beginning of the fifties, alkyl benzenesulfonates were produced by tetramerizing propylene to form branched a-dodecylene and reacting the product in a Friedel-Crafts reaction using aluminium trichloride or hydrogen fluoride to form tetrapropylene benzene which was then sulfonated and neutralized. This economic method of producing tetrapropylene benzene sulfonates (TPS) led to the breakthrough of this class of surfactants which subsequently displaced soaps as the main surfactant in detergents.
In view of the biological non-degradability of TPS, new alkyl benzenesulfonates distinguished by improved ecological behavior had to be produced. These requirements are satisfied by linear alkyl benzenesulfonates which, today, are virtually the only alkyl benzenesulfonates in production and which are referred to in short by the initials ABS.
Linear alkyl benzenesulfonates are prepared from linear alkyl benzenes which in turn can be obtained from linear olefins. To this end, petroleum fractions are separated using molecular sieves into the n-paraffins with the requisite purity and dehydrogenated to the n-olefins, both a- and i-olefins being obtained. The olefins thus obtained are then reacted with benzene in the presence of acidic catalysts to form the alkyl benzenes, the choice of the Friedel-Crafts catalyst having an influence on the isomer distribution of the linear alkyl benzenes formed. Where aluminium trichloride is used, the content of the 2-phenyl isomers in the mixture with the 3-, 4-, 5- and other isomers is approximately 30% by weight. If, by contrast, hydrogen fluoride is used as the catalyst, the 2-phenyl isomer content can be reduced to around 20% by weight. Finally, the sulfonation of the linear alkyl benzenes is now carried out on an industrial scale with oleum, sulfuric acid or gaseous sulfur trioxide, gaseous sulfur trioxide having by far the greatest importance. Special falling-film or tube-bundle reactors are used for the sulfonation process and give as the end product a 97% by weight alkyl benzenesulfonic acid (ABSA) which may be marketed as such or neutralized with NaOH to form water-containing ABS pastes with active substance contents of around 60% by weight which are then marketed.
Various salts, i.e. alkyl benzene sulfonates, can be obtained from the ABSA, depending on the choice of the neutralizing agent. For reasons of economy, it is preferred to produce and use the alkali metal salts of ABSA, preferably the sodium salts. The sodium salts correspond to general formula I:
H
H3C-(CH2)x-C-(CH2)y-CH3 S03Na (I), in which the sum of x and y is normally between 5 and 13. According to the invention, preferred compounds are characterized in that they contain the alkali metal salts and preferably the sodium salts of C$_~6 and preferably C9_~3 alkyl benzenesulfonic acids derived from alkyl benzenes having a tetralin content of less than 5% by weight, based on the alkyl benzene.
Another preferred embodiment is characterized by the use in the compounds according to the invention of alkyl benzenesulfonates of which the alkyl benzenes have been produced by the HF process, so that compounds containing the alkali metal salts and preferably the sodium salts of C8_~6, preferably C9_~3 alkyl benzene sulfonic acids which have a 2-phenyl isomer content below 22% by weight, based on the alkyl benzenesulfonic acid, are preferred.

The compounds according to the invention contain one or more hydrotrope(s) as a second key constituent. Although they are not themselves solvents, these substances have the effect that poorly soluble substances can be better dissolved in water in their presence. Preferred compounds contain, based on their weight, from 6 to 35% by weight, preferably from 7.5 to 30% by weight, more preferably from 10 to 25% by weight and most preferably from 12.5 to 20%
by weight of hydrotrope(s).
Certain hydrotropes are preferably used for the purposes of the invention.
These preferred hydrotropes belong to the group of short-chain alkyl benzenesulfonates of which the alkyl groups contain in all at most 6 carbon atoms, short-chain carboxylic acids and salts thereof, sugars and highly water-soluble covalent compounds.
Preferred compounds contain aromatic sulfonates corresponding to formula II:
x+
~ Ks (II) in which each of the substituents R~, R2, R3, R4 and R5 independently of one another is selected from H or a C~_5 alkyl or alkenyl group and X is a cation, as hydrotrope.
Preferred substituents R~, R2, R3, R4 and R5 independently of one another are selected from H or a methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert.butyl, n-pentyl, isopentyl or neopentyl group. In general, at least three of the substituents R' to R5 are hydrogen atoms, aromatic sulfonates in which three or four substituents at the aromatic ring are hydrogen atoms being preferred. The remaining substituent or the remaining two substituents may occupy any position to the sulfonate group and to one another. In the case of monosubstituted compounds corresponding to formula I, R3 is preferably an alkyl group while R~, R2, R4 and RS preferably represent H (para substitution).

According to the invention, particularly preferred aromatic sulfonates are toluene, cumene and xylene sulfonate.
Of the two commercially obtainable toluenesulfonates (ortho- and para-toluenesulfonate), the para-isomer is preferred for the purposes of the invention.
Among the cumemesulfonates, too, the para-isopropyl benzenesulfonate is the preferred compound. Since, on an industrial scale, xylene is mostly used as an isomer mixture, even the commercially obtainable xylenesulfonate is a mixture of several compounds resulting from the sulfonation of ortho, meta- and para-xylene. These isomer mixture are dominated by those compounds in which the following substituents in general formula I are methyl groups (all other substituents stand for H); R~ and R2, R~ and R4, R~ and R3 and R~ and R5. In the case of the xylenesulfonates, therefore, at least one methyl group is preferably in the ortho-position to the sulfonate group.
X in general formula I stands for a cation, for example an alkali metal cation, such as sodium or potassium. However, X may also stand for the charge-equivalent portion of a polyvalent cation, for example for Mg2+/2 or AI3+/3.
Of the cations mentioned, sodium is preferred.
Particularly preferred compounds are characterized in that, based on their weight, they contain 6 to 35% by weight, preferably 7.5 to 30% by weight, more preferably 10 to 25% by weight and most preferably 12.5 to 20% by weight of sodium para-toluenesulfonate (R3 = CH3, R~ = RZ = R4 = R5 = H, X = Na).
Other preferred compounds according to the invention contain, based on their weight, 6 to 35% by weight, preferably 7.5 to 30% by weight, more preferably 10 to 25% by weight and most preferably 12.5 to 20% by weight of sodium para-cumenesulfonate (R3 = CH(CH3)2, R' = R2 = R4 = R5 = H, X = Na).
According to the invention, other preferred hydrotropes are carboxylic acids and salts thereof. In this case, compounds containing one or more mono-, di-, tri- or oligocarboxylic acids and/or salts thereof as hydrotrope are preferred, fumaric acid, L(+) ascorbic acid, L-(-) malic acid, malefic acid, malonic acid, DL
malefic acid, citric acid and alkali metal salts thereof being particularly preferred.
Sugars may also be used in the compounds according to the invention.
Preferred compounds contain one or more sugars as hydrotrope, lactose, L(-) sorbose, D(+) galactose, D(+) glucose, sucrose, D(+) mannose, melibiose, D(-) fructose being particularly preferred.
Last but not least, readily water-soluble, non-salt-like compounds are particularly suitable as hydrotropes for the purposes of the invention.
Compounds containing one or more covalent compounds with a solubility in 5 water of more than 200 g per liter water at 20°C, preferably more than 400 g per liter water at 20°C and, more preferably, more than 700 g per liter water at 20°C
as hydrotrope, urea and N-methyl acetamide being particularly preferred, are also preferred.
Besides anionic surfactants) and hydrotrope(s), the compounds according 10 to the invention may contain other ingredients. Depending on the nature and quantity of the two compulsory constituents, carrier materials) may have to be incorporated in the compounds in order to improve their processability and stability in storage. Compounds according to the invention containing - based on their weight - 1 to 30% by weight, preferably 2.5 to 20% by weight, more preferably 4 to 15% by weight and most preferably 5 to 10% by weight of carrier materials) are preferred.
Preferred carrier materials are in particular builders, of which the silicates, carbonates and zeolites have proved to be suitable. Silicas and sulfates are also particularly suitable carrier materials. Alkali metal silicates and alkali aluminium silicates are described in detail hereinafter in the description of the builders.
Silicas are compounds with the general formula Si02 ~ nH20. Whereas the lower members, such as orthosilicic acid and pyrosilicic acid, are only stable in aqueous solution, silicon dioxide (Si02)x, the anhydride of silicic acid, occurs as the formal end product of the condensation. During the condensation reaction, chain-extending, ring-forming and branching processes take place alongside one another so that the polysilicic acids are amorphous. In all silicas, the Si atoms are located in the middle of tetrahedrons which are irregularly attached to one another and at the four corners of which the oxygen atoms also belonging to the adjacent tetrahedrons are present. The silicas are distinguished to a particular degree by an ability to form colloidal solutions of polysilicic acids in which the silica particles have particle sizes of 5 to 150 nm. These are known as silica sols.
They are unstable to further condensation and can be converted by aggregation into silica gels.

So far as industrial-scale production is concerned, precipitated silicas are by far the most important. They are produced from an aqueous alkali metal silicate solution by precipitation with mineral acids. Colloidal primary particles are formed and, as the reaction progresses, agglomerate and finally grow into aggregates. The powder-form voluminous forms have pore volumes of 2.5 to 15 ml/g and specific surfaces of 30 to 800 mz/g. Pyrogenic silicas is the generic term for highly disperse silicas which are produced by flame hydrolysis. In flame hydrolysis, silicon tetrachloride is decomposed in an oxyhydrogen flame.
Pyrogenic silicas have far fewer OH groups than precipitated silicas on their substantially pore-free surface. Known commercially available pyrogenic silicas are, for example, Aerosil~ (Degussa), Cab-O-Sil~ (Cabot Corporation, Waltham, Massachusetts) and HDK (highly disperse silicas).
Besides the silicas and the builders, more particularly silicates and aluminium silicates (zeolites), described in detail hereinafter, highly porous polymers and dried polymer gels, for example polymer powders from the group of polyvinyl alcohols, polyacrylates, polyurethanes and polyvinyl pyrrolidones, are also suitable as carrier materials for the compounds.
Particularly preferred compounds according to the invention are characterized in that they contain one or more materials from the group consisting of sodium sulfate, sodium carbonate, sodium hydrogen carbonate and/or from the groups of sodium silicates and zeolites as carrier material.
The present invention also relates to detergent tablets containing the compounds according to the invention, specifically detergent tablets of compacted particulate detergent, which are characterized in that they contain a compound according to the invention.
The compound according to the invention is preferably used in quantities below 20% by weight. Preferred detergent tablets are characterized in that they contain the compound in quantities of 0.1 to 20% by weight, preferably 0.25 to 15% by weight, more preferably 0.5 to 10% by weight and most preferably 1 to 5% by weight, based on the weight of the tablet.
Besides the compounds used in accordance with the invention, the detergent tablets according to the invention contain surfactants) and builders) as the most important ingredients of detergents and optionally other ingredients.

Disintegration aids are mentioned as further additives which are not normally used in detergents, but which can have advantageous effects in tablets.
In order to facilitate the disintegration of heavily compacted tablets, disintegration aids, so-called tablet disintegrators, may be incorporated in them to shorten their disintegration times. According to Rompp (9th Edition, Vol. 6, page 4440) and Voigt "Lehrbuch der pharmazeutischen Technologie" (8th Edition, 1987, pages 182-184), tablet disintegrators or disintegration accelerators are auxiliaries which promote the rapid disintegration of tablets in water or gastric juices and the release of the pharmaceuticals in an absorbable form.
These substances, which are also known as "disintegrators" by virtue of their effect, are capable of undergoing an increase in volume on contact with water so that, on the one hand, their own volume is increased (swelling) and, on the other hand, a pressure can be generated through the release of gases which causes the tablet to disintegrate into relatively small particles. Well-known disintegrators are, for example, carbonate/citric acid systems, although other organic acids may also be used. Swelling disintegration aids are, for example, synthetic polymers, such as polyvinyl pyrrolidone (PVP), or natural polymers and modified natural substances, such as cellulose and starch and derivatives thereof, alginates or casein derivatives.
Preferred detergent tablets contain 0.5 to 10% by weight, preferably 3 to 7% by weight and more preferably 4 to 6% by weight of one or more disintegration aids, based on the weight of the tablet.
According to the invention, preferred disintegrators are cellulose-based disintegrators, so that preferred detergent tablets contain a cellulose-based disintegrator in quantities of 0.5 to 10% by weight, preferably 3 to 7% by weight and more preferably 4 to 6% by weight. Pure cellulose has the formal empirical composition (C6H~o05)~ and, formally, is a ~-1,4-polyacetal of cellobiose which, in turn, is made up of 2 molecules of glucose. Suitable celluloses consist of ca.

to 5000 glucose units and, accordingly, have average molecular weights of 50,000 to 500,000. According to the invention, cellulose derivatives obtainable from cellulose by polymer-analog reactions may also be used as cellulose-based disintegrators. These chemically modified celluloses include, for example, products of esterification or etherification reactions in which hydroxy hydrogen atoms have been substituted. However, celluloses in which the hydroxy groups have been replaced by functional groups that are not attached by an oxygen atom may also be used as cellulose derivatives. The group of cellulose derivatives includes, for example, alkali metal celluloses, carboxymethyl cellulose (CMC), cellulose esters and ethers and aminocelluloses. The cellulose derivatives mentioned are preferably not used on their own, but rather in the form of a mixture with cellulose as cellulose-based disintegrators. The content of cellulose derivatives in mixtures such as these is preferably below 50% by weight and more preferably below 20% by weight, based on the cellulose-based disintegrator. In one particularly preferred embodiment, pure cellulose free from cellulose derivatives is used as the cellulose-based disintegrator.
The cellulose used as disintegration aid is preferably not used in fine particle form, but is converted into a coarser form, for example by granulation or compacting, before it is added to and mixed with the premixes to be tabletted.
Detergent tablets which contain granular or optionally co-granulated disintegrators are described in German patent applications DE 197 09 991 (Stefan Herzog) and DE 197 10 254 (Henkel) and in International patent application WO 98140463 (Henkel). Further particulars of the production of granulated, compacted or co-granulated cellulose disintegrators can also be found in these patent applications. The particle sizes of such disintegration aids is mostly above 200 Nm, at least 90% by weight of the particles being between 300 and 1600 Nm in size and, more particularly, between 400 and 1200 Nm in size. According to the invention, the above-described relatively coarse-particle cellulose-based disintegrators described in detail in the cited patent applications are preferably used as disintegration aids and are commercially obtainable, for example under the name of Arbocel~ TF-30-HG from Rettenmaier.
Microcrystalline cellulose may be used as another cellulose-based disintegration aid or as part of such a component. This microcrystalline cellulose is obtained by partial hydrolysis of the celluloses under conditions which only attack and completely dissolve the amorphous regions (ca. 30% of the total cellulose mass) of the celluloses, but leave the crystalline regions (ca. 70%) undamaged. Subsequent de-aggregation of the microfine celluloses formed by hydrolysis provides the microcrystalline celluloses which have primary particle sizes of ca. 5 Nm and which can be compacted, for example, to granules with a mean particle size of 200 pm.
Preferred detergent tablets according to the invention additionally contain a disintegration aid, preferably a cellulose-based disintegration aid, preferably in granular, cogranulated or compacted form, in quantities of 0.5 to 10% by weight, preferably 3 to 7% by weight and more preferably 4 to 6% by weight, based on tablet weight.
The detergent tablets according to the invention additionally contain one or more builders. Any of the builders normally used in detergents may be present in the detergent tablets according to the invention, including in particular zeolites, silicates, carbonates, organic co-builders and also - providing there are no ecological objections to their use - phosphates.
Suitable crystalline layer-form sodium silicates correspond to the general formula NaMSiX02X+~A y H20, where M is sodium or hydrogen, x is a number of 1.9 to 4 and y is a number of 0 to 20, preferred values for x being 2, 3 or 4.
Preferred crystalline layer silicates corresponding to the above formula are those in which M is sodium and x assumes the value 2 or 3. Both ~- and s-sodium disilicates Na2Si205A y HZO are particularly preferred.
Other useful builders are amorphous sodium silicates with a modulus (Na20:Si02 ratio) of 1:2 to 1:3.3, preferably 1:2 to 1:2.8 and more preferably 1:2 to 1:2.6 which dissolve with delay and exhibit multiple wash cycle properties.
The delay in dissolution in relation to conventional amorphous sodium silicates can have been obtained in various ways, for example by surface treatment, compounding, compacting or by overdrying. In the context of the invention, the term ~amorphous0 is also understood to encompass ~X-ray amorphous. In other words, the silicates do not produce any of the sharp X-ray reflexes typical of crystalline substances in X-ray diffraction experiments, but at best one or more maxima of the scattered X-radiation which have a width of several degrees of the diffraction angle. However, particularly good builder properties may even be achieved where the silicate particles produce crooked or even sharp diffraction maxima in electron diffraction experiments. This may be interpreted to mean that the products have microcrystalline regions between 10 and a few hundred nm in size, values of up to at most 50 nm and, more particularly, up to at most 20 nm being preferred. So-called X-ray amorphous silicates such as these, which also dissolve with delay in relation to conventional waterglasses, are described for 5 example in German patent application DE-A-44 00 024. Compacted amorphous silicates, compounded amorphous silicates and overdried X-ray-amorphous silicates are particularly preferred.
The finely crystalline, synthetic zeolite containing bound water used in accordance with the invention is preferably zeolite A and/or zeolite P.
Zeolite 10 MAP~ (Crosfield) is a particularly preferred P-type zeolite. However, zeolite X
and mixtures of A, X and/or P are also suitable. According to the invention, it is also preferred to use, for example, a co-crystallizate of zeolite X and zeolite A
(ca. 80% by weight zeolite X) which is marketed by CONDEA Augusta S.p.A.
under the name of VEGOBOND AX~ and which may be described by the 15 following formula:
nNa20 ~ (1-n)KZO ~ AI203 ~ (2 - 2.5)Si02 ~ (3.5 - 5.5) H20.
The zeolite may be used both as a builder in a granular compound and as a kind of "powder" to be applied to the entire mixture to be tabletted, both routes normally being used to incorporate the zeolite in the premix. Suitable zeolites have a mean particle size of less than 10 ~m (volume distribution, as measured by the Coulter Counter Method) and contain preferably 18 to 22% by weight and more preferably 20 to 22% by weight of bound water.
The generally known phosphates may of course also be used as builders providing their use should not be avoided on ecological grounds. Among the large number of commercially available phosphates, alkali metal phosphates have the greatest importance in the detergent industry, pentasodium triphosphate and pentapotassium triphosphate (sodium and potassium tripolyphosphate) being particularly preferred.
"Alkali metal phosphates" is the collective term for the alkali metal (more particularly sodium and potassium) salts of the various phosphoric acids, including metaphosphoric acids (HP03)~ and orthophosphoric acid (H3P04) and representatives of higher molecular weight. The phosphates combine several advantages: they act as alkalinity sources, prevent lime deposits on machine parts and lime incrustations in fabrics and, in addition, contribute towards the cleaning effect.
Sodium dihydrogen phosphate (NaH2P04) exists as the dehydrate (density 1.91 gcm-3, melting point 60°) and as the monohydrate (density 2.04 gcm-3). Both salts are white readily water-soluble powders which, on heating, lose the water of crystallization and, at 200°C, are converted into the weakly acidic diphosphate (disodium hydrogen diphosphate, Na2H2P20~) and, at higher temperatures, into sodium trimetaphosphate (Na3P309) and Maddrell's salt (see below). NaH2P04 shows an acidic reaction. It is formed by adjusting phosphoric acid with sodium hydroxide to a pH value of 4.5 and spraying the resulting "mash". Potassium dihydrogen phosphate (primary or monobasic potassium phosphate, potassium biphosphate, KDP), KH2P04, is a white salt with a density of 2.33 gcm-3, has a melting point of 253° [decomposition with formation of potassium polyphosphate (KP03)X] and is readily soluble in water.
Disodium hydrogen phosphate (secondary sodium phosphate), Na2HP04, is a colorless, readily water-soluble crystalline salt. It exists in water-free form and with 2 moles (density 2.066 gcm-3, water loss at 95°), 7 moles (density 1.68 gcm-3, melting point 48° with loss of 5 H20) and 12 moles of water (density 1.52 gcm 3, melting point 35° with loss of 5 H20), becomes water-free at 100° and, on fairly intensive heating, is converted into the diphosphate Na4P207. Disodium hydrogen phosphate is prepared by neutralization of phosphoric acid with soda solution using phenolphthalein as indicator. Dipotassium hydrogen phosphate (secondary or dibasic potassium phosphate), K2HP04, is an amorphous white salt which is readily soluble in water.
Trisodium phosphate, tertiary sodium phosphate, Na3P04, consists of colorless crystals which have a density of 1.62 gcm-3 and a melting point of 76° (decomposition) as the dodecahydrate, a melting point of 100° as the decahydrate (corresponding to 19-20% P205) and a density of 2.536 gcm-3 in water-free form (corresponding to 39-40% P205). Trisodium phosphate is readily soluble in water through an alkaline reaction and is prepared by concentrating a solution of exactly 1 mole of disodium phosphate and 1 mole of NaOH by evaporation. Tripotassium phosphate (tertiary or tribasic potassium phosphate), K3P04, is a white deliquescent granular powder with a density of 2.56 gcm 3, has a melting of 1340° and is readily soluble in water through an alkaline reaction. It is formed, for example, when Thomas slag is heated with coal and potassium sulfate. Despite their higher price, the more readily soluble and therefore highly effective potassium phosphates are often preferred to corresponding sodium compounds in the detergent industry.
Tetrasodium diphosphate (sodium pyrophosphate), Na4P207, exists in water-free form (density 2.534 gcm-3, melting point 988°, a figure of 880° has also been mentioned) and as the decahydrate (density 1.815 - 1.836 gcm 3, melting point 94° with loss of water). Both substances are colorless crystals which dissolve in water through an alkaline reaction. Na4P207 is formed when disodium phosphate is heated to >200° or by reacting phosphoric acid with soda in a stoichiometric ratio and spray-drying the solution. The decahydrate complexes heavy metal salts and hardness salts and, hence, reduces the hardness of water.
Potassium diphosphate (potassium pyrophosphate), K4P20~, exists in the form of the trihydrate and is a colorless hygroscopic powder with a density of 2.33 gcm-3 which is soluble in water, the pH value of a 1 % solution at 25° being 10.4.
Relatively high molecular weight sodium and potassium phosphates are formed by condensation of NaH2P04 or KH2P04. They may be divided into cyclic types, namely the sodium and potassium metaphosphates, and chain types, the sodium and potassium polyphosphates. The chain types in particular are known by various different names: fused or calcined phosphates, Graham's salt, Kurrol's salt and Maddrell's salt. All higher sodium and potassium phosphates are known collectively as condensed phosphates.
The industrially important pentasodium triphosphate, Na5P30~o (sodium tripolyphosphate), is a non-hygroscopic white water-soluble salt which crystallizes without water or with 6 H20 and which has the general formula Na0-[P(O)(ONa)-O]~-Na where n = 3. Around 17 g of the salt free from water of crystallization dissolve in 100 g of water at room temperature, around 20 g at 60° and around 32 g at 100°. After heating of the solution for 2 hours to 100°, around 8%
orthophosphate and 15% diphosphate are formed by hydrolysis. In the preparation of pentasodium triphosphate, phosphoric acid is reacted with soda solution or sodium hydroxide in a stoichiometric ratio and the solution is spray-dried. Similarly to Graham's salt and sodium diphosphate, pentasodium triphosphate dissolves many insoluble metal compounds (including lime soaps, etc.). Pentapotassium triphosphate, K5P30~o (potassium tripolyphosphate), is marketed for example in the form of a 50% by weight solution (> 23% P205, 25%
K20). The potassium polyphosphates are widely used in the detergent industry.
Sodium potassium tripolyphosphates, which may also be used in accordance with the invention, also exist. They are formed for example when sodium trimetaphosphate is hydrolyzed with KOH:
(NaP03)3 + 2 KOH ~ Na3K2P30~o + H20 According to the invention, they may be used in exactly the same way as sodium tripolyphosphate, potassium tripolyphosphate or mixtures thereof.
Mixtures of sodium tripolyphosphate and sodium potassium tripolyphosphate or mixtures of potassium tripolyphosphate and sodium potassium tripolyphosphate or mixtures of sodium tripolyphosphate and potassium tripolyphosphate and sodium potassium tripolyphosphate may also be used in accordance with the invention.
Organic cobuilders suitable for use in the detergent tablets according to the invention are, in particular, polycarboxylates/polycarboxylic acids, polymeric polycarboxylates, aspartic acid, polyacetals, dextrins, other organic cobuilders (see below) and phosphonates. These classes of substances are described in the following.
Useful organic builders are, for example, the polycarboxylic acids usable, for example, in the form of their sodium salts, polycarboxylic acids in this context being understood to be carboxylic acids which bear more than one acid function.
Examples of such carboxylic acids are citric acid, adipic acid, succinic acid, glutaric acid, malic acid, tartaric acid, malefic acid, fumaric acid, sugar acids, aminocarboxylic acids, nitrilotriacetic acid (NTA), providing their use is not ecologically unsafe, and mixtures thereof. Preferred salts are the salts of the polycarboxylic acids, such as citric acid, adipic acid, succinic acid, glutaric acid, tartaric acid, sugar acids and mixtures thereof.
The acids per se may also be used. Besides their builder effect, the acids also typically have the property of an acidifying component and, hence, also serve to establish a relatively low and mild pH value in detergents. Citric acid, succinic acid, glutaric acid, adipic acid, gluconic acid and mixtures thereof are particularly mentioned in this regard.
Other suitable builders are polymeric polycarboxylates such as, for example, the alkali metal salts of polyacrylic or polymethacrylic acid, for example those with a relative molecular weight of 500 to 70,000 g/mole.
The molecular weights mentioned in this specification for polymeric polycarboxylates are weight-average molecular weights MW of the particular acid form which, basically, were determined by gel permeation chromatography (GPC) using a UV detector. The measurement was carried out against an external polyacrylic acid standard which provides realistic molecular weight values by virtue of its structural similarity to the polymers investigated. These values differ distinctly from the molecular weights measured against polystyrene sulfonic acids as standard. The molecular weights measured against polystyrene sulfonic acids are generally higher than the molecular weights mentioned in this specification.
Particularly suitable polymers are polyacrylates which preferably have a molecular weight of 2,000 to 20,000 g/mole. By virtue of their superior solubility, preferred representatives of this group are the short-chain polyacrylates which have molecular weights of 2,000 to 10,000 g/mole and, more particularly, 3,000 to 5,000 g/mole.
Also suitable are copolymeric polycarboxylates, particularly those of acrylic acid with methacrylic acid and those of acrylic acid or methacrylic acid with malefic acid. Acrylic acid/maleic acid copolymers containing 50 to 90% by weight of acrylic acid and 50 to 10% by weight of malefic acid have proved to be particularly suitable. Their relative molecular weights, based on the free acids, are generally in the range from 2,000 to 70,000 g/mole, preferably in the range from 20,000 to 50,000 g/mole and more preferably in the range from 30,000 to 40,000 g/mole.
The (co)polymeric polycarboxylates may be used either in powder form or in the form of an aqueous solution. The content of (co)polymeric polycarboxylates in the detergent is preferably from 0.5 to 20% by weight and more preferably from 3 to 10% by weight.
In order to improve solubility in water, the polymers may also contain allyl sulfonic acids, such as allyloxybenzene sulfonic acid and methallyl sulfonic acid 5 for example, as monomer.
Other particularly preferred polymers are biodegradable polymers of more than two different monomer units, for example those which contain salts of acrylic acid and malefic acid and vinyl alcohol or vinyl alcohol derivatives as monomers or those which contain salts of acrylic acid and 2-alkylallyl sulfonic acid and sugar 10 derivatives as monomers.
Other preferred builders are polymeric aminodicarboxylic acids, salts or precursors thereof. Particular preference is attributed to polyaspartic acids or salts and derivatives thereof which also have a bleach-stabilizing efFect in addition to their co-builder properties.
15 Other suitable builders are polyacetals which may be obtained by reaction of dialdehydes with polyol carboxylic acids containing 5 to 7 carbon atoms and at least 3 hydroxyl groups. Preferred polyacetals are obtained from dialdehydes, such as glyoxal, glutaraldehyde, terephthalaldehyde and mixtures thereof and from polyol carboxylic acids, such as gluconic acid and/or glucoheptonic acid.

20 Other suitable organic builders are dextrins, for example oligomers or polymers of carbohydrates which may be obtained by partial hydrolysis of starches. The hydrolysis may be carried out by standard methods, for example acid- or enzyme-catalyzed methods. The end products are preferably hydrolysis products with average molecular weights of 400 to 500,000 g/mole. A
polysaccharide with a dextrose equivalent (DE) of 0.5 to 40 and, more particularly, 2 to 30 is preferred, the DE being an accepted measure of the reducing effect of a polysaccharide by comparison with dextrose which has a DE
of 100. Both maltodextrins with a DE of 3 to 20 and dry glucose sirups with a DE
of 20 to 37 and also so-called yellow dextrins and white dextrins with relatively high molecular weights of 2,000 to 30,000 g/mole may be used.
The oxidized derivatives of such dextrins are their reaction products with oxidizing agents which are capable of oxidizing at least one alcohol function of the saccharide ring to the carboxylic acid function. An oxidized oligosaccharide is also suitable. A product oxidized at C6 of the saccharide ring can be particularly advantageous.
Other suitable co-builders are oxydisuccinates and other derivatives of disuccinates, preferably ethylenediamine disuccinate. Ethylenediamine-N,N'-disuccinate (EDDS) is preferably used in the form of its sodium or magnesium salts. Glycerol disuccinates and glycerol trisuccinates are also preferred in this connection. The quantities used in zeolite-containing and/or silicate-containing formulations are from 3 to 15% by weight.
Other useful organic co-builders are, for example, acetylated hydroxycarboxylic acids and salts thereof which may optionally be present in lactone form and which contain at least 4 carbon atoms, at least one hydroxy group and at most two acid groups.
Another class of substances with co-builder properties are the phosphonates, more particularly hydroxyalkane and aminoalkane phosphonates.
Among the hydroxyalkane phosphonates, 1-hydroxyethane-1,1-diphosphonate (HEDP) is particularly important as a co-builder. It is preferably used in the form of the sodium salt, the disodium salt showing a neutral reaction and the tetrasodium salt an alkaline reaction (pH 9). Preferred aminoalkane phosphonates are ethylenediamine tetramethylene phosphonate (EDTMP), diethylenetriamine pentamethylenephosphonate (DTPMP) and higher homologs thereof. They are preferably used in the form of the neutrally reacting sodium salts, for example as the hexasodium salt of EDTMP or as the hepta- and octasodium salts of DTPMP. Of the phosphonates, HEDP is preferably used as a builder. In addition, the aminoalkane phosphonates have a pronounced heavy metal binding capacity. Accordingly, it can be of advantage, particularly where the detergents also contain bleach, to use aminoalkane phosphonates, more particularly DTPMP, or mixtures of the phosphonates mentioned.
In addition, any compounds capable of forming complexes with alkaline earth metal ions may be used as co-builders.
The quantity of builder used is normally between 10 and 70% by weight, preferably between 15 and 60% by weight and more preferably between 20 and 50% by weight. The quantity of builder used is again dependent upon the particular application envisaged, so that bleach tablets can contain larger quantities of builders (for example between 20 and 70% by weight, preferably between 25 and 65% by weight and more preferably between 30 and 55% by weight) than, for example, laundry detergent tablets (normally 10 to 50% by weight, preferably 12.5 to 45% by weight and more preferably 17.5 to 37.5% by weight).
Besides the anionic surfactant present in the compounds, the detergent tablets according to the invention may contain other anionic surfactants.
Nonionic, cationic and zwitterionic surfactants may also be used.
Preferred detergent tablets additionally contain one or more surfactant(s).
Anionic, nonionic, cationic and/or amphoteric surfactants or mixtures thereof may be used in the detergent tablets according to the invention. Mixtures of anionic and nonionic surfactants are preferred from the performance point of view. The total surfactant content of the tablets is between 5 and 60% by weight, based on tablet weight, surfactant contents above 15% by weight being preferred.
Dishwasher tablets may contain surfactants in smaller quantities, for example below 2% by weight.
Preferred nonionic surfactants are alkoxylated, advantageously ethoxylated, more especially primary alcohols preferably containing 8 to 18 carbon atoms and, on average, 1 to 12 moles of ethylene oxide (EO) per mole of alcohol, in which the alcohol component may be linear or, preferably, methyl-branched in the 2-position or may contain linear and methyl-branched residues in the form of the mixtures typically present in oxoalcohol residues. However, alcohol ethoxylates containing linear residues of alcohols of native origin with 12 to 18 carbon atoms, for example coconut, palm, tallow or oleyl alcohol, and on average 2 to 8 EO per mole of alcohol are particularly preferred. Preferred ethoxylated alcohols include, for example, C~2_~4 alcohols containing 3 EO or EO, C9_» alcohol containing 7 EO, C~3-~5 alcohols containing 3 EO, 5 EO, 7 EO
or 8 EO, C~2_~$ alcohols containing 3 EO, 5 EO or 7 EO and mixtures thereof, such as mixtures of C~2_~4 alcohol containing 3 EO and C~2_~8 alcohol containing 5 EO. The degrees of ethoxylation mentioned represent statistical mean values which, for a special product, can be a whole number or a broken number.
Preferred alcohol ethoxylates have a narrow homolog distribution (narrow range ethoxylates, NRE). In addition to these nonionic surfactants, fatty alcohols containing more than 12 EO may also be used, examples including tallow fatty alcohol containing 14 EO, 25 EO, 30 EO or 40 EO.
Other nonionic surfactants which may be used are alkyl glycosides corresponding to the general formula RO(G)X where R is a primary linear or 2 methyl-branched aliphatic radical containing 8 to 22 and preferably 12 to 18 carbon atoms and G stands for a glycose unit containing 5 or 6 carbon atoms, preferably glucose. The degree of oligomerization x, which indicates the distribution of monoglycosides and oligoglycosides, is a number of 1 to 10; x preferably has a value of 1.2 to 1.4.
Another class of preferred nonionic surfactants which may be used either as sole nonionic surfactant or in combination with other nonionic surfactants are alkoxylated, preferably ethoxylated or ethoxylated and propoxylated, fatty acid alkyl esters preferably containing 1 to 4 carbon atoms in the alkyl chain, more particularly fatty acid methyl esters.
Nonionic surfactants of the amine oxide type, for example N-cocoalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxyethylamine oxide, and the fatty acid alkanolamide type are also suitable. The quantity in which these nonionic surfactants are used is preferably no more than the quantity in which the ethoxylated fatty alcohols are used and, more preferably, no more than half that quantity.
Other suitable surfactants are polyhydroxyfatty acid amides corresponding to formula (III):
R' R-CO-N-[Z] (I I I) in which RCO is an aliphatic acyl group containing 6 to 22 carbon atoms, R' is hydrogen, an alkyl or hydroxyalkyl group containing 1 to 4 carbon atoms and [Z]
is a linear or branched polyhydroxyalkyl group containing 3 to 10 carbon atoms and 3 to 10 hydroxyl groups. The polyhydroxyfatty acid amides are known substances which may normally be obtained by reductive amination of a reducing sugar with ammonia, an alkylamine or an alkanolamine and subsequent acylation with a fatty acid, a fatty acid alkyl ester or a fatty acid chloride.

The group of polyhydroxyfatty acid amides also includes compounds corresponding to formula (V):
R'-O-R2 R-CO-N-[Z] (IV) in which R is a linear or branched alkyl or alkenyl group containing 7 to 12 carbon atoms, R~ is a linear, branched or cyclic alkyl group or an aryl group containing 2 to 8 carbon atoms and R2 is a linear, branched or cyclic alkyl group or an aryl group or an oxyalkyl group containing 1 to 8 carbon atoms, C~~ alkyl or phenyl groups being preferred, and [Z] is a linear polyhydroxyalkyl group, of which the alkyl chain is substituted by at least two hydroxyl groups, or alkoxylated, preferably ethoxylated or propoxylated, derivatives of that group.
[Z] is preferably obtained by reductive amination of a reduced sugar, for example glucose, fructose, maltose, lactose, galactose, mannose or xylose. The N-alkoxy- or N-aryloxy-substituted compounds may then be converted into the required polyhydroxyfatty acid amides by reaction with fatty acid methyl esters in the presence of an alkoxide as catalyst.
According to the invention, preferred detergent tablets contain anionic and nonionic surfactant(s). Performance-related advantages can arise out of certain quantity ratios in which the individual classes of surfactants are used.
Particularly preferred detergent tablets contain anionic and/or nonionic surfactants) and have total surfactant contents above 2.5% by weight, preferably above 5% by weight and more preferably above 10% by weight, based on tablet weight.
For example, particularly preferred detergent tablets are characterized in that the ratio of anionic surfactants) to nonionic surfactants) is from 10:1 to 1:10, preferably from 7.5:1 to 1:5 and more preferably from 5:1 to 1:2. Other preferred detergent tablets are characterized in that they contain surfactant(s), preferably anionic and/or nonionic surfactant(s), in quantities of 5 to 40% by weight, preferably 7.5 to 35% by weight, more preferably 10 to 30% by weight and most preferably 12.5 to 25% by weight, based on the weight of the tablet.
It can be of advantage from the performance point of view if certain classes of surfactants are missing from certain phases of the detergent tablets or from the entire tablet, i.e. from every phase. In another important embodiment of the present invention, therefore, at least one phase of the tablets is free from nonionic surfactants.
Conversely, a positive effect can also be obtained through the presence of 5 certain surfactants in individual phases or in the tablet as a whole, i.e.
in every phase. Introducing the alkyl polyglycosides described above has proved to be of particular advantage, so that detergent tablets in which at least one phase of the tablet contains alkyl polyglycosides are preferred.
As with the nonionic surfactants, the omission of anionic surfactants from 10 individual phases or from all phases can result in detergent tablets which are more suitable for certain applications. Accordingly, detergent tablets where at least one phase of the tablet is free from anionic surfactants are also possible in accordance with the present invention.
Besides the ingredients mentioned thus far (surfactant, builder and 15 disintegration aid) and in addition to the binder compound present in the tablets in accordance with the invention, the detergent tablets according to the invention may contain other substances from the group of bleaching agents, bleach activators, enzymes, pH regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, optical brighteners, 20 discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.
Among the compounds yielding H202 in water which serve as bleaching agents, sodium perborate tetrahydrate and sodium perborate monohydrate are particularly important. Other useful bleaching agents are, for example, sodium percarbonate, peroxypyrophosphates, citrate perhydrates and H202-yielding 25 peracidic salts or peracids, such as perbenzoates, peroxophthalates, diperazelaic acid, phthaloiminoperacid or diperdodecane dioic acid. Where bleaching agents are used, it is again possible to leave out surfactants and/or builders so that pure bleach tablets can be produced. If such bleach tablets are to be added to laundry, a combination of sodium percarbonate with sodium sesquicarbonate is preferably used irrespective of what other ingredients the tablets contain. If detergent or bleach tablets for dishwashing machines are being produced, bleaching agents from the group of organic bleaches may also be used. Typical organic bleaching agents are diacyl peroxides, such as dibenzoyl peroxide for example. Other typical organic bleaching agents are the peroxy acids, of which alkyl peroxy acids and aryl peroxy acids are particularly mentioned as examples.
Preferred representatives are (a) peroxybenzoic acid and ring-substituted derivatives thereof, such as alkyl peroxybenzoic acids, but also peroxy-a-naphthoic acid and magnesium monoperphthalate, (b) aliphatic or substituted aliphatic peroxy acids, such as peroxylauric acid, peroxystearic acid, s-phthalimidoperoxycaproic acid [phthaloiminoperoxyhexanoic acid (PAP)], o-carboxybenzamidoperoxycaproic acid, N-nonenylamidoperadipic acid and N-nonenylamidopersuccinates, and (c) aliphatic and araliphatic peroxydicarboxylic acids, such as 1,12-diperoxycarboxylic acid, 1,9-diperoxyazelaic acid, diperoxysebacic acid, diperoxybrassylic acid, diperoxyphthalic acids, 2-decyldiperoxybutane-1,4-dioic acid, N,N-terephthaloyl-di(6-aminopercaproic acid).
Other suitable bleaching agents in dishwasher tablets are chlorine- and bromine-releasing substances. Suitable chlorine- or bromine-releasing materials are, for example, heterocyclic N-bromamides and N-chloramides, for example trichloroisocyanuric acid, tribromoisocyanuric acid, dibromoisocyanuric acid and/or dichloroisocyanuric acid (DICA) and/or salts thereof with cations, such as potassium and sodium. Hydantoin compounds, such as 1,3-dichloro-5,5-dimethyl hydantoin, are also suitable.
In order to obtain an improved bleaching effect at washing temperatures of 60°C or lower, bleach activators may be incorporated as a sole constituent or as an ingredient of component b). According to the invention, compounds which form aliphatic peroxocarboxylic acids preferably containing 1 to 10 carbon atoms and more preferably 2 to 4 carbon atoms and/or optionally substituted perbenzoic acid under perhydrolysis conditions may be used as bleach activators. Suitable bleach activators are substances which contain O- and/or N-acyl groups with the number of carbon atoms indicated and/or optionally substituted benzoyl groups.
Preferred bleach activators are polyacylated alkylenediamines, more especially tetraacetyl ethylenediamine (TAED), acylated triazine derivatives, more particularly 1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine (DADHT), acylated glycol urils, more particularly tetraacetyl glycol uril (TAGU), N-acylimides, more particularly N-nonanoyl succinimide (NOSI), acylated phenol sulfonates, more particularly n-nonanoyl- or isononanoyl-oxybenzenesulfonate (n- or iso-NOBS), carboxylic anhydrides, more especially phthalic anhydride, acylated polyhydric alcohols, more especially triacetin, ethylene glycol diacetate and 2,5-diacetoxy-2, 5-d ihyd rofu ran.
In addition to or instead of the conventional bleach activators, so-called bleach catalysts may also be incorporated in the tablets. Bleach catalysts are bleach-boosting transition metal salts or transition metal complexes such as, for example, Mn-, Fe-, Co-, Ru- or Mo-salen complexes or carbonyl complexes.
Mn-, Fe-, Co-, Ru-, Mo-, Ti-, V- and Cu-complexes with N-containing tripod ligands and Co-, Fe-, Cu- and Ru-ammine complexes may also be used as bleach catalysts. According to the invention, bleach-boosting active-substance combinations obtainable by thoroughly mixing a water-soluble salt of a divalent transition metal selected from cobalt, iron, copper and ruthenium and mixtures thereof, a water-soluble ammonium salt and optionally a peroxygen-based oxidizing agent and inert carrier materials may also be used as bleach catalysts.
Suitable enzymes are, in particular, those from the classes of hydrolases, such as proteases, esterases, lipases or lipolytic enzymes, amylases, cellulases or other glycosyl hydrolases and mixtures thereof. All these hydrolases contribute to the removal of stains, such as protein-containing, fat-containing or starch-containing stains, and discoloration in the washing process. Cellulases and other glycosyl hydrolases can contribute towards color retention and towards increasing fabric softness by removing pilling and microfibrils.
Oxidoreductases may also be used for bleaching and for inhibiting dye transfer. Enzymes obtained from bacterial strains or fungi, such as Bacillus subtilis, Bacillus licheniformis, Streptomyces griseus, Coprinus cinereus and Humicola insolens and from genetically modified variants are particularly suitable. Proteases of the subtilisin type are preferably used, proteases obtained from Bacillus lentus being particularly preferred. Of particular interest in this regard are enzyme mixtures, for example of protease and amylase or protease and lipase or lipolytic enzymes or protease and cellulase or of cellulase and lipase or lipolytic enzymes or of protease, amylase and lipase or lipolytic enzymes or protease, lipase or lipolytic enzymes and cellulase, but especially protease- and/or lipase-containing mixtures or mixtures with lipolytic enzymes. Examples of such lipolytic enzymes are the known cutinases. Peroxidases or oxidases have also been successfully used in some cases. Suitable amylases include in particular a-amylases, isoamylases, pullanases and pectinases. Preferred cellulases are cellobio-hydrolases, endoglucanases and ~i-glucosidases, which are also known as cellobiases, and mixtures thereof. Since the various cellulase types differ in their CMCase and avicelase activities, the desired activities can be established by mixing the cellulases in the appropriate ratios.
The enzymes may be adsorbed to supports and/or encapsulated in membrane materials to protect them against premature decomposition. The percentage content of the enzymes, enzyme mixtures or enzyme granules may be, for example, from about 0.1 to 5% by weight and is preferably from 0.5 to about 4.5% by weight.
The choice of the particular enzymes is also dependent on the application envisaged for the detergent tablets according to the invention. Suitable enzymes for dishwasher tablets are, in particular, those from the classes of hydrolases, such as proteases, esterases, lipases or lipolytic enzymes, amylases, glycosyl hydrolases and mixtures thereof. All these hydrolases contribute to the removal of stains, such as protein-containing, fat-containing or starch-containing stains.
Oxidoreductases may also be used for bleaching. Enzymes obtained from bacterial strains or fungi, such as Bacillus subtilis, Bacillus licheniformis, Streptomyces griseus, Coprinus cinereus and Humicola insolens and from genetically modified variants are particularly suitable. Proteases of the subtilisin type are preferably used, proteases obtained from Bacillus lentus being particularly preferred. Of particular interest in this regard are enzyme mixtures, for example of protease and amylase or protease and lipase or lipolytic enzymes or of protease, amylase and lipase or lipolytic enzymes or protease, lipase or lipolytic enzymes, but especially protease- and/or lipase-containing mixtures or mixtures with lipolytic enzymes. Examples of such lipolytic enzymes are the known cutinases. Peroxidases or oxidases have also been successfully used in some cases. Suitable amylases include in particular a-amylases, isoamylases, pullanases and pectinases.

In dishwasher tablets also, the enzymes may be adsorbed to supports and/or encapsulated in membrane materials to protect them against premature decomposition. The percentage content of the enzymes, enzyme mixtures or enzyme granules may again be, for example, from about 0.1 to 5% by weight and is preferably from 0.5 to about 4.5% by weight.
Dishwasher tablets according to the invention may contain corrosion inhibitors to protect the tableware or the machine itself, silver protectors being particularly important for dishwashing machines. Known silver protectors may be used. Above all, silver protectors selected from the group of triazoles, benzotriazoles, bisbenzotriazoles, aminotriazoles, alkylaminotriazoles and the transition metal salts or complexes may generally be used. Benzotriazole and/or alkylaminotriazole is/are particularly preferred. In addition, dishwashing formulations often contain corrosion inhibitors containing active chlorine which are capable of distinctly reducing the corrosion of silver surfaces. Chlorine-free dishwashing detergents contain in particular oxygen and nitrogen-containing organic redox-active compounds, such as dihydric and trihydric phenols, for example hydroquinone, pyrocatechol, hydroxyhydroquinone, gallic acid, phloroglucinol, pyrogallol and derivatives of these compounds. Salt-like and complex-like inorganic compounds, such as salts of the metals Mn, Ti, Zr, Hf, V, Co and Ce are also frequently used. Of these, the transition metal salts selected from the group of manganese and/or cobalt salts and/or complexes are preferred, cobalt(ammine) complexes, cobalt(acetate) complexes, cobalt(carbonyl) complexes, chlorides of cobalt or manganese and manganese sulfate being particularly preferred. Zinc compounds may also be used to protect tableware against corrosion.
In addition, the detergent tablets may also contain components with a positive effect on the removability of oil and fats from textiles by washing (so-called soil repellents). This effect becomes particularly clear when a textile which has already been repeatedly washed with a detergent according to the invention containing this oil- and fat-dissolving component is soiled. Preferred oil-and fat-dissolving components include, for example, nonionic cellulose ethers, such as methyl cellulose and methyl hydroxypropyl cellulose containing 15 to 30% by weight of methoxyl groups and 1 to 15% by weight of hydroxypropoxyl groups, based on the nonionic cellulose ether, and the polymers of phthalic acid and/or terephthalic acid known from the prior art or derivatives thereof, more particularly polymers of ethylene terephthalates and/or polyethylene glycol terephthalates or anionically and/or nonionically modified derivatives thereof. Of these, the 5 sulfonated derivatives of phthalic acid and terephthalic acid polymers are particularly preferred.
The tablets may contain derivatives of diaminostilbenedisulfonic acid or alkali metal salts thereof as optical brighteners. Suitable optical brighteners are, for example, salts of 4,4'-bis-(2-anilino-4-morpholino-1,3,5-triazinyl-6-amino)-10 stilbene-2,2'-disulfonic acid or compounds of similar composition which contain a diethanolamino group, a methylamino group, an anilino group or a 2-methoxyethylamino group instead of the morpholino group. Brighteners of the substituted diphenyl styryl type, for example alkali metal salts of 4,4'-bis-(2-sulfostyryl)-diphenyl, 4,4'-bis-(4-chloro-3-sulfostyryl)-diphenyl or 4-(4-15 chlorostyryl)-4'-(2-sulfostyryl)-Biphenyl, may also be present. Mixtures of the brighteners mentioned above may also be used.
Dyes and perfumes are added to the detergent tablets according to the invention to improve the aesthetic impression created by the products and to provide the consumer not only with the required washing performance but also 20 with a visually and sensorially "typical and unmistakable" product.
Suitable perfume oils or perfumes include individual perfume compounds, for example synthetic products of the ester, ether, aldehyde, ketone, alcohol and hydrocarbon type. Perfume compounds of the ester type are, for example, benzyl acetate, phenoxyethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl acetate, dimethyl 25 benzyl carbinyl acetate, phenyl ethyl acetate, linalyl benzoate, benzyl formate, ethyl methyl phenyl glycinate, allyl cyclohexyl propionate, styrallyl propionate and benzyl salicylate. The ethers include, for example, benzyl ethyl ether; the aldehydes include, for example, the linear alkanals containing 8 to 18 carbon atoms, citral, citronellal, citronellyloxyacetaldehyde, cyclamen aldehyde, 30 hydroxycitronellal, lilial and bourgeonal; the ketones include, for example, the ionones, a-isomethyl ionone and methyl cedryl ketone; the alcohols include anethol, citronellol, eugenol, geraniol, linalool, phenyl ethyl alcohol and terpineol and the hydrocarbons include, above all, the terpenes, such as limonene and pinene. However, mixtures of various perfumes which together produce an attractive perfume note are preferably used. Perfume oils such as these may also contain natural perfume mixtures obtainable from vegetable sources, for example pine, citrus, jasmine, patchouli, rose or ylang-ylang oil. Also suitable are clary oil, camomile oil, clove oil, melissa oil, mint oil, cinnamon leaf oil, lime blossom oil, juniper berry oil, vetiver oil, olibanum oil, galbanum oil and labdanum oil and orange blossom oil, neroli oil, orange peel oil and sandalwood oil.
The detergent tablets according to the invention normally contain less than 0.01 % by weight of dyes whereas perfumes/fragrances can make up as much as 2% by weight of the formulation as a whole.
The perfumes may be directly incorporated in the detergents according to the invention, although it can also be of advantage to apply the perfumes to supports which strengthen the adherence of the perfume to the washing and which provide the textiles with a long-lasting fragrance through a slower release of the perfume. Suitable support materials are, for example, cyclodextrins, the cyclodextrin/perfume complexes optionally being coated with other auxiliaries.
In order to improve their aesthetic impression, the detergents according to the invention may be colored with suitable dyes. Preferred dyes, which are not difficult for the expert to choose, have high stability in storage, are not affected by the other ingredients of the detergents or by light and do not have any pronounced substantivity for textile fibers so as not to color them.
Detergent tablets are produced by applying pressure to a mixture to be tabletted which is accommodated in the cavity of a press. In the most simple form of tabletting, the mixture to be tabletted is tabletted directly, i.e.
without preliminary granulation. The advantages of this so-called direct tabletting lie in its simple and inexpensive application because no other process steps and hence no other items of equipment are required. However, these advantages are often offset by disadvantages. Thus, a powder mixture which is to be directly tabletted must show adequate plasticity and good flow properties and should not have any tendency to separate during storage, transportation and filling of the die.
With many mixtures, these three requirements are very difficult to satisfy with the result that direct tabletting is often not applied, particularly in the production of detergent tablets. Accordingly, the normal method of producing detergent tablets starts out from powder-form components ("primary particles") which are agglomerated or granulated by suitable methods to form secondary particles with a larger particle diameter. These granules or mixtures of different granules are then mixed with individual powder-form additives and tabletted.
Accordingly, the present invention also relates to a process for the production of detergent tablets by tabletting a particulate premix in known manner, characterized in that the premix contains one or more compounds according to the invention.
Multiphase tablets may also be produced in accordance with the invention, two-layer tablets being the most simple embodiment of a multiphase tablet.
Accordingly, the present invention also relates to a process for the production of multiphase detergent tablets by tabletting several particulate premixes in known manner, characterized in that at least one of the premixes contains one or more compounds according to the invention.
So far as preferred embodiments of the process according to the invention are concerned, reference may be made here to the foregoing observations: what was said in reference to the detergent tablets according to the invention applies similarly to the process according to the invention. For example, preferred processes according to the invention are characterized in that the premixes) contains) compounds) in quantities of 0.1 to 20% by weight, preferably in quantities of 0.25 to 15% by weight, more preferably in quantities of 0.5 to 10%
by weight and most preferably in quantities of 1 to 5% by weight, based on the weight of the premix.
In preferred variants of the process, the compounds also satisfy certain particle size criteria. Thus, preferred processes according to the invention are characterized in that the compounds) has/have a mean particle size below 1,000 Nm, preferably below 850 Nm and more preferably below 700 pm. In a particularly preferred embodiment, the compounds) is/are free from particles larger than 1200 Nm in size, preferably free from particles larger than 1000 Nm in size and more preferably free from particles larger than 900 Nm in size.
Fines are also preferably removed from the compounds to be used in accordance with the invention before tabletting. Preferred processes according to the invention are characterized in that the compounds) is/are free from particles below 100 pm in size, preferably free from particles below 200 Nm in size and more preferably free from particles below 300 Nm in size.
According to the invention, preferred detergent tablets are produced by tabletting a particulate premix of surfactant-containing granules of at least one type and at least one powder-form component subsequently added. The surfactant-containing granules may be produced by conventional industrial granulation processes, such as compacting, extrusion, mixer granulation, pelleting or fluidized bed granulation. It is of advantage so far as the subsequent detergent tablets are concerned if the premix to be tabletted has a bulk density approaching that of typical compact detergents. In one particularly preferred embodiment, at least one particulate premix additionally contains surfactant-containing granules) and has a bulk density of at least 500 g/I, preferably of at least 600 g/I and more preferably of at least 700 g/I.
In preferred variants of the process, the surfactant-containing granules also satisfy certain particle size criteria. Thus, preferred processes according to the invention are characterized in that the surfactant-containing granules have particle sizes of 100 to 2000 Nm, preferably 200 to 1800 Nm, more preferably to 1600 Nm and most preferably 600 to 1400 pm.
Besides the active substances (anionic and/or nonionic and/or cationic and/or amphoteric surfactants), the surfactant granules preferably contain carrier materials which, in one particularly preferred embodiment, emanate from the group of builders. Accordingly, particularly advantageous processes are characterized in that the surfactant-containing granules contain anionic and/or nonionic surfactants and builders and have total surfactant contents of at least 10% by weight, preferably at least 20% by weight and more preferably at least 25% by weight.
Before the particulate premix is compressed to form detergent tablets, it may be "powdered" with fine-particle surface treatment materials. This can be of advantage to the quality and physical properties of both the premix (storage, tabletting) and the final detergent tablets. Fine-particle powdering materials have been known for some time in the art, zeolites, silicates and other inorganic salts generally being used. However, the premix is preferably "powdered" with fine-particle zeolite, zeolites of the faujasite type being preferred. In the context of the present invention, the expression "zeolite of the faujasite type" encompasses all three zeolites which form the faujasite subgroup of zeolite structural group 4 (cf.
Donald W. Breck: "Zeolite Molecular Sieves" John Wiley & Sons, New York/London/Sydney/Toronto, 1974, page 92). Besides zeolite X, therefore, zeolite Y and faujasite and mixtures of these compounds may also be used, pure zeolite X being preferred. Mixtures or co-crystallizates of faujasite zeolites with other zeolites which need not necessarily belong to zeolite structure group 4 may also be used as powdering materials, in which case at least 50% by weight of the powdering material advantageously consists of a faujasite zeolite.
According to the invention, preferred detergent tablets consist of a particulate premix containing granular components and powder-form substances subsequently added, the - or one of the - powder-form components subsequently incorporated being a faujasite zeolite with particle sizes below 100 Nm, preferably below 10 Nm and more preferably below 5 pm and making up at least 0.2% by weight, preferably at least 0.5% by weight and more preferably more than 1 %
by weight of the premix to be tabletted.
Besides the components mentioned (surfactant, builder and disintegration aid), the premixes to be tabletted may additionally contain one or more substances from the group of bleaching agents, bleach activators, disintegration aids, enzymes, pH regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, optical brighteners, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.
These substances are described in the foregoing.
The present invention also relates to a process for the production of detergent tablets which comprises the steps of a) producing a compound of aa) 60 to 95% by weight of anionic surfactant(s), ab) 5 to 40% by weight of hydrotrope(s) and ac) 0 to 35% by weight of carrier material(s), b) producing surfactant-containing granules, c) mixing the compound from step a) and the granules from step b) with other ingredients of detergents and d) compressing the premix formed in step c) to form tablets or regions thereof.
So far as the choice of suitable machines and process parameters for steps a) and b) are concerned, the expert may resort to machines and apparatus 5 known from the literature and to the technical operations described, for example, in W. Pietsch, "Size Enlargement by Agglomeration" Wiley, 1991, and the literature cited therein. The following observations represent only a small part of the range of possibilities available to the expert for carrying out both steps of the process according to the invention.
10 The compounds according to the invention may be carried out by granulation or forming processes known per se, granulation of the solid constituents initially introduced into the mixer with the liquid constituents being preferred. This variant of process step a) is appropriate, for example, when solid neutralizing agent is introduced first and the alkyl benzenesulfonic acid is added 15 to the bed of solids which also contains the hydrotropes. If only solids are to be processed, as is the case with the processing of alkyl benzenesulfonates, such processes as roll compacting and pelleting (ring die presses) are appropriate.
The production of surfactant granules {step b) of the process according to the invention} may be carried out in various conventional mixers and granulators.
20 Mixers suitable for carrying out step b) of the process according to the invention are, for example, Series R or RV Eirich~ mixers (trademarks of Maschinenfabrik Gustav Eirich, Hardheim), the Schugi~ Flexomix, Fukae~ FS-G mixers (trademarks of Fukae Powtech, Kogyo Co., Japan}, Lodige~ FM, KM and CB
mixers (trademarks of Lodige Maschinenbau GmbH, Paderborn) or Series T or K-25 T Drais~ mixers (trademarks of Drais-Werke GmbH, Mannheim). Some preferred embodiments of step b) of the process according to the invention are described in the following.
For example, it is possible and preferred to carry out process step b) in a low-speed mixer/granulator at peripheral speeds of the tools of 2 m/s to 7 m/s.
30 Alternatively, in preferred variants of the process, step b) may be carried out in a high-speed mixer/granulator at peripheral speeds of 8 m/s to 35 m/s.
Whereas the two process variants described above each use a mixer, it is also possible in accordance with the invention to combine two mixers with one another. For example, preferred processes are characterized in that, in step a), a liquid granulation aid is added to an agitated bed of solids in a first low-speed mixer/granulator, 40 to 100% by weight, based on the total quantity of constituents used, of the solid and liquid constituents being pregranulated and the "pregranules" from the first process step optionally being mixed with the remaining solid and/or liquid constituents and converted into granules in a second high-speed mixer/ granulator. In this variant of the process, a granulation aid is added to a bed of solids in a first mixer/granulator and the mixture is pregranulated. The composition of the granulation aid and of the bed of solids introduced into the first mixer are selected so that 40 to 100% by weight, preferably 50 to 90% by weight and more preferably 60 to 80% by weight of the solid and liquid constituents, based on the total quantity of constituents used, are contained in the "pregranules". These "pregranules" are then mixed with more solids in the second mixer and granulated in the presence of more liquid components to form the final surfactant granules.
According to the invention, the above-mentioned sequence of low-speed/high-speed mixers may also be reversed, resulting in a process according to the invention in which the liquid granulation aid is added to an agitated bed of solids in a first high-speed mixer/granulator, 40 to 100% by weight, based on the total quantity of constituents used, of the solid and liquid constituents being pregranulated and the pregranules from the first process step optionally being mixed with the remaining solid and/or liquid constituents and converted into granules in a second low-speed mixer/granulator.
All the variants of the process according to the invention described in the foregoing may be carried out either in batches or continuously. High-speed mixer/granulators are used in some of the above-described variants of step a) of the process according to the invention. In one particularly preferred embodiment of the invention, a mixer comprising both a mixing unit and a size-reducing unit is used as a high-speed mixer, the mixing shaft being driven at peripheral speeds of 50 to 150 r.p.m. and preferably 60 to 80 r.p.m. and the shaft of the size-reducing unit being driven at rotational speeds of 500 to 5000 r.p.m. and preferably to 3000 r. p. m.

Preferred granulation processes for the production of mixer granules are carried out in mixer granulators in which certain parts of the mixer or the entire mixer is/are heated to temperatures at least 20°C above the temperature which the materials to be granulated have at the beginning of the granulation process.
Accordingly, if solids which have been stored at 20°C and which enter the mixer with this temperature are granulated, certain parts of the mixer or the mixer as a whole preferably have/has a temperature of at least 40°C. Overall, however, a temperature of 120°C for the mixer parts or for the mixer as a whole should not be exceeded. If only certain parts of the mixer are heated to the temperatures mentioned, the parts in question are preferably the mixer walls or the mixer tools.
The mixer walls can be brought to the required temperature by a heatable jacket while the mixer tools can be brought to the required temperature by built-in heating elements.
In the production of surfactant-containing granules in completely or partly heated mixers, it is also preferred to use non-aqueous granulation aids, more particularly nonionic surfactants, which have a melting point of 20 to 50°C. The preferred granulation process described above enables the bulk density of the surfactant granules to be increased and, at the same time, unwanted caking on the walls of the mixer to be distinctly reduced. The use of surfactant granules produced in this way in tablettable premixes leads to detergent tablets which are distinguished from mixtures containing conventionally produced granules by a further reduced disintegration time.
The production of the surfactant granules {step b) of the process according to the invention} can also be carried out by press agglomeration processes, the products often being referred to as press granules. Their production {in step b) of the process according to the invention} is carried out by press agglomeration processes, preferably by extrusion, roller compacting or pelleting.
In all the press agglomeration processes mentioned, the premix is compacted and plasticized under pressure and under the effect of shear forces, homogenized and then discharged from the machines via a forming/ shaping stage.
In a preferred embodiment of process step b), the premix is preferably delivered continuously to a planetary roll extruder or to a twin-screw extruder with co-rotating or contra-rotating screws, of which the barrel and the extruder/granulation head may be heated to the predetermined extrusion temperature. Under the shearing effect of the extruder screws, the premix is compacted under pressure (preferably at least 25 bar or - with extremely high throughputs - even lower, depending on the machine used), plasticized, extruded in the form of fine strands through the multiple-bore die in the extruder head and, finally, the extrudate is chopped by means of a rotating blade into preferably substantially spherical or cylindrical granules. The bore diameter of the multiple-bore extrusion die and the length to which the extruded strands are cut are adapted to the size selected for the granules. In this embodiment, it is possible to produce granules with a substantially uniform predetermined particle size, the absolute particle sizes being adaptable to the particular application envisaged.
The particle diameters described in the foregoing are generally preferred. In one important embodiment, the length-to-diameter ratio of the primary granules formed by cutting the extruded strands is between about 1:1 and about 3:1. In another preferred embodiment, the still plastic primary granules are subjected to another shaping or forming step in which the edges present on the crude extrudate are rounded off so that spherical or substantially spherical extrudate granules can ultimately be obtained. If desired, small quantities of dry powder, for example zeolite powder, such as zeolite NaA powder, may be used in this step which may be carried out in commercially available spheronizers. It is important to ensure that only small quantities of fines are formed in this step.
Alternatively, extrusion/compression can also be carried out in low-pressure extruders, in a Kahl press or in a Bextruder.
As in the extrusion process, it is preferred in the other production processes to subject the primary granules/compactates formed to another shaping process step, more particularly to spheronizing, so that spherical or substantially spherical (bead-like) granules can be obtained.
In another preferred embodiment of the present invention, step b) of the process the process according to the invention is carried out by roll compacting.
In this process, the premix for the press granules is introduced between two rollers - either smooth or provided with depressions of defined shape - and rolled under pressure between the two rollers to form a sheet-like compactate. The rollers exert a high linear pressure on the premix and may be additionally heated or cooled as required. Where smooth rollers are used, smooth untextured compactate sheets are obtained. By contrast, where textured rollers are used, correspondingly textured compactates, in which for example certain shapes can be imposed in advance on the subsequent press granules, can be produced.
The sheet-like compactate is then broken up into smaller pieces by a chopping and size-reducing process and can thus be processed to granules which can be further refined by further surface treatment processes, more particularly converted into a substantially spherical shape.
In another preferred embodiment of the present invention, step b) of the process according to the invention is carried out by pelleting. In this process, the premix for the press granules is applied to a perforated surface and is forced through the perforations by a pressure roller. In conventional pellet presses, the premix is compacted under pressure, plasticized, forced through a perforated surface in the form of fine strands by means of a rotating roller and, finally, is size-reduced to granules by a cutting unit. The pressure roller and the perforated die may assume many different forms. For example, flat perforated plates are used, as are concave or convex ring dies through which the material is pressed by one or more pressure rollers. In perforated-plate presses, the pressure rollers may also be conical in shape. In ring die presses, the dies and pressure rollers) may rotate in the same direction or in opposite directions. A press suitable for carrying out the process according to the invention is described, for example, in DE-OS 38 16 842 (Schluter GmbH). The ring die press disclosed in this document consists of a rotating ring die permeated by pressure bores and at least one pressure roller operatively connected to the inner surface thereof which presses the material delivered to the die space through the pressure bores into a discharge unit. The ring die and pressure roller are designed to be driven in the same direction which reduces the shear load applied to the premix and hence the increase in temperature which it undergoes. However, the pelleting process may of course also be carried out with heatable or coolable rollers to enable the premix to be adjusted to a required temperature.
The tablets according to the invention are produced by first dry-mixing the ingredients - which may be completely or partly pregranulated - and then shaping/forming, more particularly tabletting, the resulting mixture using conventional processes. To produce the tablets according to the invention, the premix is compacted between two punches in a die to form a solid compactate.
This process, which is referred to in short hereinafter as tabletting, comprises four 5 phases, namely dosing, compacting (elastic deformation), plastic deformation and ejection.
The premix is first introduced into the die, the filling level and hence the weight and shape of the tablet formed being determined by the position of the lower punch and the shape of the die. Uniform dosing, even at high tablet 10 throughputs, is preferably achieved by volumetric dosing of the premix. As the tabletting process continues, the top punch comes into contact with the premix and continues descending towards the bottom punch. During this compaction phase, the particles of the premix are pressed closer together, the void volume in the filling between the punches continuously diminishing. The plastic deformation 15 phase in which the particles coalesce and form the tablet begins from a certain position of the top punch (and hence from a certain pressure on the premix).
Depending on the physical properties of the premix, its constituent particles are also partly crushed, the premix sintering at even higher pressures. As the tabletting rate increases, i.e. at high throughputs, the elastic deformation phase 20 becomes increasingly shorter so that the tablets formed can have more or less large voids. In the final step of the tabletting process, the tablet is forced from the die by the bottom punch and carried away by following conveyors. At this stage, only the weight of the tablet is definitively established because the tablets can still change shape and size as a result of physical processes (re-elongation, 25 crystallographic effects, cooling, etc.).
The tabletting process is carried out in commercially available tablet presses which, in principle, may be equipped with single or double punches. In the latter case, not only is the top punch used to build up pressure, the bottom punch also moves towards the top punch during the tabletting process while the 30 top punch presses downwards. For small production volumes, it is preferred to use eccentric tablet presses in which the punches) is/are fixed to an eccentric disc which, in turn, is mounted on a shaft rotating at a certain speed. The movement of these punches is comparable with the operation of a conventional four-stroke engine. Tabletting can be carried out with a top punch and a bottom punch, although several punches can also be fixed to a single eccentric disc, in which case the number of die bores is correspondingly increased. The throughputs of eccentric presses vary according to type from a few hundred to at most 3,000 tablets per hour.
For larger throughputs, rotary tablet presses are generally used. In rotary tablet presses, a relatively large number of dies is arranged in a circle on a so-called die table. The number of dies varies - according to model - between 6 and 55, although even larger dies are commercially available. Top and bottom punches are associated with each die on the die table, the tabletting pressures again being actively built up not only by the top punch or bottom punch, but also by both punches. The die table and the punches move about a common vertical axis, the punches being brought into the filling, compaction, plastic deformation and ejection positions by means of curved guide rails. At those places where the punches have to be raised or lowered to a particularly significant extent (filling, compaction, ejection), these curved guide rails are supported by additional push-down members, pull-down rails and ejection paths. The die is filled from a rigidly arranged feed unit, the so-called filling shoe, which is connected to a storage container for the premix. The pressure applied to the premix can be individually adjusted through the tools for the top and bottom punches, pressure being built up by the rolling of the punch shank heads past adjustable pressure rollers.
To increase throughput, rotary presses can also be equipped with two filling shoes so that only half a circle has to be negotiated to produce a tablet. To produce two-layer or multiple-layer tablets, several filling shoes are arranged one behind the other without the lightly compacted first layer being ejected before further filling. Given suitable process control, shell and bull's-eye tablets -which have a structure resembling an onion skin - can also be produced in this way.
In the case of bull's-eye tablets, the upper surface of the core or rather the core layers is not covered and thus remains visible. Rotary tablet presses can also be equipped with single or multiple punches so that, for example, an outer circle with 50 bores and an inner circle with 35 bores can be simultaneously used for tabletting. Modern rotary tablet presses have throughputs of more than one million tablets per hour.

Where rotary presses are used for tabletting, it has proved to be of advantage to carry out the tabletting process with minimal variations in the weight of the tablets. Variations in tablet hardness can also be reduced in this way.
Minimal variations in weight can be achieved as follows:
- using plastic inserts with minimal thickness tolerances - low rotor speed - large filling shoe - adapting the rotational speed of the filling shoe blade to the rotor speed - filling shoe with constant powder height - decoupling the filling shoe from the powder supply.
Any of the nonstick coatings known in the art may be used to reduce caking on the punch. Plastic coatings, plastic inserts or plastic punches are particularly advantageous. Rotating punches have also proved to be of advantage; if possible, the upper and lower punches should be designed for rotation. If rotating punches are used, there will generally be no need for a plastic insert. In that case, the surfaces of the punch should be electropolished.
It has also been found that long tabletting times are advantageous. These can be achieved by using pressure rails, several pressure rollers or low rotor speeds. Since variations in tablet hardness are caused by variations in the pressures applied, systems which limit the tabletting pressure should be used.
Elastic punches, pneumatic compensators or spring elements in the force path may be used. The pressure roller can also be spring-mounted.
Tabletting machines suitable for the purposes of the invention can be obtained, for example, from the following companies: Apparatebau Holzwarth GbR, Asperg; Wilhelm Fette GmbH, Schwarzenbek; Hofer GmbH, Weil; Horn &
Noack Pharmatechnik GmbH, Worms; IMA Verpackungssysteme GmbH Viersen;
KILIAN, Cologne; KOMAGE, Kell am See, KORSCH Pressen GmbH, Berlin; and Romaco GmbH, Worms. Other suppliers are, for example Dr. Herbert Pete, Vienna (AU); Mapag Maschinenbau AG, Bern (Switzerland); BWI Manesty, Liverpool (GB); I. Holand Ltd., Nottingham (GB); and Courtoy N.V., Halle (BE/LU) and Medicopharm, Kamnik (SI). One example of a particularly suitable tabletting machine is the model HPF 630 hydraulic double-pressure press manufactured by LAEIS, D. Tabletting tools are obtainable, for example, from Adams Tablettierwerkzeuge Dresden; Wilhelm Fett GmbH, Schwarzenbek; Klaus Hammer, Solingen; Herber & Sohne GmbH, Hamburg; Hofer GmbH, Weil; Horn & Noack, Pharmatechnik GmbH, Worms; Ritter Pharmatechnik GmbH, Hamburg;
Romaco GmbH, Worms and Notter Werkzeugbau, Tamm. Other suppliers are, for example, Senss AG, Reinach (CH) and Medicopharm, Kamnik (SI).
The tablets can be made in certain shapes and certain sizes. Suitable shapes are virtually any easy-to-handle shapes, for example slabs, bars, cubes, squares and corresponding shapes with flat sides and, in particular, cylindrical forms of circular or oval cross-section. This last embodiment encompasses shapes from tablets to compact cylinders with a height-to-diameter ratio of more than 1.
The portioned pressings may be formed as separate individual elements which correspond to a predetermined dose of the detergent. However, it is also possible to form pressings which combine several such units in a single pressing, smaller portioned units being easy to break off in particular through the provision of predetermined weak spots. For the use of laundry detergents in machines of the standard European type with horizontally arranged mechanics, it can be of advantage to produce the portioned pressings as cylindrical or square tablets, preferably with a diameter-to-height ratio of about 0.5:2 to 2:0.5.
Commercially available hydraulic presses, eccentric presses and rotary presses are particularly suitable for the production of pressings such as these.
The three-dimensional form of another embodiment of the tablets according to the invention is adapted in its dimensions to the dispensing compartment of commercially available domestic washing machines, so that the tablets can be introduced directly, i.e. without a dosing aid, into the dispensing compartment where they dissolve on contact with water. However, it is of course readily possible - and preferred in accordance with the present invention - to use the detergent tablets in conjunction with a dosing aid.
Another preferred tablet which can be produced has a plate-like or slab-like structure with alternately thick long segments and thin short segments, so that individual segments can be broken off from this "bar" at the predetermined weak spots, which the short thin segments represent, and introduced into the machine. This "bar" principle can also be embodied in other geometric forms, for example vertical triangles which are only joined to one another at one of their longitudinal sides.
In another possible embodiment, however, the various components are not compressed to form a single tablet, instead the tablets obtained comprise several layers, i.e. at least two layers. These various layers may have different dissolving rates. This can provide the tablets with favorable performance properties. If, for example, the tablets contain components which adversely affect one another, one component may be integrated in the more quickly dissolving layer while the other component may be incorporated in a more slowly dissolving layer so that the first component can already have reacted off by the time the second component dissolves. The various layers of the tablets can be arranged in the form of a stack, in which case the inner layers) dissolve at the edges of the tablet before the outer layers have completely dissolved.
Alternatively, however, the inner layers) may also be completely surrounded by the layers lying further to the outside which prevents constituents of the inner layers) from dissolving prematurely.
In another preferred embodiment of the invention, a tablet consists of at least three layers, i.e. two outer layers and at least one inner layer, a peroxy bleaching agent being present in at least one of the inner layers whereas, in the case of the stack-like tablet, the two cover layers and, in the case of the envelope-like tablet, the outermost layers are free from peroxy bleaching agent.
In another possible embodiment, peroxy bleaching agent and any bleach activators or bleach catalysts present and/or enzymes may be spatially separated from one another in one and the same tablet. Multilayer tablets such as these have the advantage that they can be used not only via a dispensing compartment or via a dosing unit which is added to the wash liquor, instead it is also possible in cases such as these to introduce the tablet into the machine in direct contact with the fabrics without any danger of spotting by bleaching agent or the like.
Similar effects can also be obtained by coating individual constituents of the detergent composition to be compressed or the tablet as a whole. To this end, the tablets to be coated may be sprayed, for example, with aqueous solutions or emulsions or a coating may be obtained by the process known as melt coating.
After pressing, the detergent tablets have high stability. The fracture resistance of cylindrical tablets can be determined via the diametral fracture stress. This in turn can be determined in accordance with the following equation:

BDt where ~ represents the diametral fracture stress (DFS) in Pa, P is the force in N
10 which leads to the pressure applied to the tablet that results in fracture thereof, D
is the diameter of the tablet in meters and t is its height.
The present invention also relates to the use of compounds of a) 60 to 95% by weight of anionic surfactant(s), b) 5 to 40% by weight of hydrotrope(s) and 15 c) 0 to 35% by weight of carrier materials) for improving the abrasion resistance of detergent tablets.
This use of the compounds mentioned in accordance with the invention leads to tablets with advantageous properties, as the following Examples show.
The foregoing observations on the process according to the invention (particle 20 sizes, other ingredients, composition of the premix, etc.) apply equally to preferred embodiments of the use according to the invention.
Examples Surfactant-containing granules (for composition, see Table 1), which were used as the basis for tablettable premixes, were produced by granulation in a 25 liter Lodige plowshare mixer. After granulation, the granules were dried for 30 minutes in a Glatt fluidized bed dryer at an inflowing air temperature of 60°C.
After drying, fine particles (< 0.4 mm) and coarse particles (> 1.6 mm) were removed by sieving.
The surfactant granules were then mixed with other components to form 30 compressible premixes which were then tabletted in a Korsch eccentric press (tablet diameter 44 mm, weight 37.5 g). Premixes E1 and E2 according to the invention contained 1 and 2% by weight of an ABS/toluene sulfonate compound of which the composition is shown in Table 2. The particle size distributions of the compound are set out in Table 3.

The tabletting pressure was adjusted so that four series of tablets (tablet diameter 44 mm, weight 37.5 g) differing in their hardness were obtained. The series with the lowest hardness were tested for abrasion because the problem of abrasion resistance is of course at its greatest in their case. The composition of the premixes to be tabletted (and hence the tablets) is shown in Table 4.
Table 1. Composition of the surfactant granules [% by weight]
C9_~3 alkyl benzenesulfonate 19.4 C~2_~g fatty alcohol sulfate 5.2 C~2_~8 fatty alcohol x 7 EO 4.8 C~2_~6 alkyl-1,4-glycoside 1.0 Soap 1.6 Sodium carbonate 17.0 Sodium silicate 5.6 Zeolite A 28.5 Optical brightener 0.3 Na hydroxyethane-1,1-diphosphonate0.8 Acrylic acid/maleic acid copolymer*5.6 Water, salts Balance * Sokalan~ CP 5, BASF
Table 2. Composition of the ABS/toluenesulfonate compound [% by weight]
C9_~3 alkyl benzenesulfonate 79 Na toluene sulfonate 14 Sodium sulfate 6 Salts 1 Table 3. Particle size distribution of the ABS/toluenesulfonate compound [% by weight]
>1.6mm >1.2mm >0.8mm >0.4mm >0.2mm <0.2mm Table 4. Composition of the premixes [% by weight]:

Surfactant granules (Table 1) 63 62 64 Sodium percarbonate 17 17 17 TAED 7.3 7.3 7.3 Foam inhibitor 3.5 3.5 3.5 Enzymes 1.7 1.7 1.7 Perfume 0.5 0.5 0.5 ABS/toluenesulfonate compound (Table1 2 -2) Wessalith~ XD (zeolite X) 2 2 2 Disintegration aid (cellulose) 5 5 5 The hardness of the tablets was measured after two days' storage by deforming a tablet until it broke, the force being applied to the sides of the tablet and the maximum force withstood by the tablet being determined.
To determine tablet disintegration, a tablet was placed in a glass beaker filled with water (600 ml water, temperature 30°C) and the time taken by the tablet to disintegrate completely was measured.
Abrasion resistance was determined by placing a tablet on a 1.6 mm mesh sieve. The sieve was then placed in a Retsch analytical sieving machine and stressed at an amplitude of 2 mm for 120 seconds. The abrasion in % can be calculated by weighing the tablet on the sieve before and after stressing. The experimental data are shown in Table 5:

Table 5. Detergent tablets [physical data]
Tablet E E2 V

Tablet hardness [N] 29 31 28 Tablet disintegration 7 8 7 [s]

Abrasion [%] 21 22 45 Tablet hardness [N] 41 39 42 Tablet disintegration 11 12 11 [s]

Tablet hardness [N] 52 50 48 Tablet disintegration 21 19 23 [s]

Tablet hardness [N] 59 63 61 Tablet disintegration 32 29 35 [s]

The disintegration time of the detergent tablets is slightly reduced and abrasion clearly minimized by the use of the compounds according to the invention.

Claims (73)

1. A composition comprising a) 60 to 9% by weight of anionic surfactant(s), b) 5 to 40% by weight of hydrotrope(s) and c) 0 to 35% by weight of carrier material(s), based on the weight of the additive.

2. A composition as claimed in claim 1, comprising, based on its weight, 65 to 90% by weight of anionic surfactant(s).

3. A composition as claimed in claim 2, comprising 70 to 85% by weight of anionic surfactant(s).

4. A composition as claimed in claim 2, comprising 75 to 80% by weight of anionic surfactant(s).

5. A composition as claimed in any of claims 1 to 4, comprising one or more surfactants from the groups of fatty alcohol sulfates, alkyl benzenesulfonates and/or soaps as anionic surfactant(s).

6. A composition as claimed in any of claims 1 to 5, comprising alkali metal salts as anionic surfactant.

7. A composition as claimed in claim 6, wherein the alkali metal salts are the sodium salts of C9-13 alkyl benzenesulfonic acids.

8. A composition as claimed in any of claims 1 to 7, wherein, based on its weight, 6 to 35% by weight, preferably 7.5 to 30% by weight, of hydrotrope(s).

9. A composition as claimed in claim 8, wherein 7.5 to 30% by weight of hydrotrope(s) is present.

10. A composition as claimed in claim 8, wherein 10 to 25% by weight of hydrotrope(s) is present.

11. A composition as claimed in claim 8, wherein 12.5 to 20% by weight of hydrotrope(s) is present.

12. A composition as claimed in any of claims 1 to 11, wherein there is present aromatic sulfonates corresponding to formula II:

in which each of the substituents R1, R2, R3, R4 and R5 independently of one another is selected from H or a C1-5 alkyl or alkenyl group and X is a cation, as hydrotrope.

13. A composition as claimed in claim 12, wherein, based on its weight, there is present 6 to 35% by weight of sodium para-toluenesulfonate (R3 = CH3, R1 =

=R4=R5=H,X=Na).

14. A composition as claimed in claim 13, wherein there is present 7.5 to 30%
by weight of the sodium para-toluenesulfonate.

15. A composition as claimed in claim 13, wherein there is present 10 to 25%
by weight of the sodium para-toluenesulfonate.

16. A composition as claimed in claim 13, wherein there is present 12.5 to 20% by weight of the sodium para-toluenesulfonate.

17. A composition as claimed in any of claims 13 to 16, wherein, based on its weight, there is present 6 to 35% by weight of sodium para-cumenesulfonate (R3 = CH(CH3)2, R1 = R2 = R4 = R5 = H, X = Na).

18. A composition as claimed in claim 13, where there is present 7.5 to 30%
by weight of the sodium para-cumenesulfonate.

19. A composition as claimed in claim 13, where there is present 10 to 25% by weight of the sodium para-cumenesulfonate.

20. A composition as claimed in claim 13, where there is present 12.5 to 20%
by weight of the sodium para-cumenesulfonate.

21. A composition as claimed in any of claims 1 to 20, wherein there is present one or more mono-, di-, tri- or oligocarboxylic acids and/or salts thereof as hydrotrope.

22. A composition as claimed in claim 21, wherein there is present fumaric acid, L(+) ascorbic acid, L-(-) malic acid, maleic acid, malonic acid, DL
maleic acid, citric acid and alkali metal salts.

23. A composition as claimed in any of claims 1 to 22, wherein there is present one or more sugars as hydrotrope.

24. A composition as claimed in claim 23, wherein there is present lactose, L(-sorbose, D(+) galactose, D(+) glucose, sucrose, D(+) mannose, melibiose, D(-)fructose.

25 A composition as claimed in any of claims 1 to 24, wherein there is present one or more covalent compounds with a solubility in water of more than 200 g per liter water at 20°C as hydrotrope.

26. A composition as claimed in claim 25, wherein the solubility is more than 400 g per liter water at 20°C.

27. A composition as claimed in claim 25, wherein the solubility is more than 700 g per litre water at 20°C.

28. A composition as claimed in any of claims 25 to 27, wherein urea or N-methyl acetamide is present.

29. A composition as claimed in any of claims 1 to 28, wherein there is present, based on its weight, 1 to 30% by weight of carrier material(s).

30. A composition as claimed in claim 29, wherein 2.5 to 20% by weight of carrier material(s) is present.

31. A composition as claimed in claim 29, wherein 4 to 15% by weight of carrier material(s) is present.

32. A composition as claimed in claim 29, wherein 5 to 10% by weight of carrier material(s) is present.

33. A composition as claimed in any of claims 1 to 32, wherein there is present one or more materials selected from the group consisting of sodium sulfate, sodium carbonate, sodium hydrogen carbonate and/or from the groups of sodium silicates and zeolites as carrier material.

34. Detergent tablets of compacted particulate detergent, comprising the composition as claimed in any of claims 1 to 33.

35. Detergent tablets as claimed in claim 34, wherein there is present the composition in quantities of 0.1 to 20% by weight based on tablet weight.

36. Detergent tablets as claimed in claim 35, wherein 0.25 to 15% by weight is present.

37. Detergent tablets as claimed in claim 35, wherein 0.5 to 10% by weight is present.

38. Detergent tablets as claimed in claim 35, wherein 1 to 5% by weight is present.

39. Detergent tablets as claimed in any of claims 34 to 38, wherein there is additionally present a disintegration aid in quantities of 0.5 to 10% by weight based on tablet weight.

40. Detergent tablets as claimed in claim 39, wherein a cellulose-based disintegration aid is present.

41. Detergent tablets as claimed in claim 39 or 40, wherein the disintegration aid is in granular, cogranulated or compacted form.

42. Detergent tablets as claimed in claims 39 to 41, wherein the disintegration aid comprises 3 to 7% by weight.

43. Detergent tablets as claimed in claims 39 to 41, wherein the disintegration aid comprises 4 to 6% by weight.

44. Detergent tablets as claimed in any of claims 34 to 43, wherein there is present surfactant(s) in quantities of 5 to 40% by weight based on tablet weight.

45. Detergent tablets as claimed in claim 44, wherein the surfactant(s) is anionic and/or nonionic.

46. Detergent tablets as claimed in claim 44, wherein the surfactant(s) is 7.5 to 35% by weight.

47. Detergent tablets as claimed in claim 44, wherein the surfactant(s) is 10 to 30% by weight.

48. Detergent tablets as claimed in claim 44, wherein the surfactant(s) is 12.5 to 25% by weight.

49. A process for the production of detergent tablets by tabletting a particulate premix, wherein the premix comprises one or more of the compositions claimed in any of claims 1 to 33.

50. A process for the production of multiphase detergent tablets by tabletting several particulate premixes in known manner, wherein at least one of the premixes contains one or more of the compounds claimed in any of claims 1 to 33.

51. A process as claimed in claim 49 or 50, wherein the premixe(s) contain(s) 0.1 to 20% by weight of compositions based on the weight of the premix.

52. A process as claimed in claim 51, wherein 0.25 to 15% by weight is present.

53. A process as claimed in claim 51, wherein 0.5 to 10% by weight is present.

54. A process as claimed in claim 51, wherein 1 to 5% by weight is present.

55. A process as claimed in any of claims 49 to 51, wherein the composition(s) has/have a mean particle size below 1000 µm.

56. A process as claimed in claim 55, wherein the particle size is below 850 µm.

57. A process as claimed in claim 55, wherein the particle size is below 700 µm.

58. A process as claimed in any of claims 55 to 57, wherein the composition(s) is/are free from particles larger than 1200 µm in size.

59. A process as claimed in claim 58, wherein the particle sizes are larger than 1000 µm in size.

60. A process as claimed in claim 58, wherein the particle sizes are larger than 900 µm in size.

61. A process as claimed in any of claims 58 to 60, wherein the composition(s) is/are free from particles below 100 µm in size.

62. A process as claimed in claim 61, wherein the composition(s) is/are free from particles below 200 µm in size.

63. A process as claimed in claim 61, wherein the composition(s) is/are free from particles below 300 µm in size.

64. A process as claimed in any of claims 49 to 61, wherein at least one particulate premix additionally contains surfactant-containing granule(s) and has a bulk density of at least 500 g/l.

65. A process as claimed in claim 64, wherein the bulk density is at least 600 g/l.

66. A process as claimed in claim 64, wherein the bulk density is at least 700 g/l.

67. A process as claimed in any of claims 64 to 66, wherein the surfactant-containing granules have particle sizes of 100 to 2000 µm.

68. A process as claimed in claim 67, wherein the particle sizes are 200 to 1800 µm.

69. A process as claimed in claim 67, wherein the particle sizes are 400 to 1600 µm.

70. A process as claimed in claim 67, wherein the particle sizes are 600 to 1400 µm.

71. A process as claimed in any of claims 49 to 67, wherein at least one particulate premix additionally contains one or more substances from the group consisting of bleaching agents, bleach activators, disintegration aids, enzymes, pH regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, optical brighteners, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.

72. A process for the production of detergent tablets comprising the steps of a) producing a composition of aa) 60 to 95% by weight of anionic surfactant(s), ab) 5 to 40% by weight of hydrotrope(s) and ac) 0 to 35% by weight of carrier material(s), b) producing surfactant-containing granules, c) mixing the composition from step a) and the granules from step b) with other ingredients of detergents and d) compressing the premix formed in step c) to form tablets or regions thereof.

73. The use of compositions of a) 60 to 95% by weight of anionic surfactant(s), b) 5 to 40% by weight of hydrotrope(s) and c) 0 to 35% by weight of carrier material(s) for improving the abrasion resistance of detergent tablets.