CA2306722A1

CA2306722A1 - Detergent tablets containing binder compound

Info

Publication number: CA2306722A1
Application number: CA 2306722
Authority: CA
Inventors: Peter Schmiedel; Patrick Kahlke; Ute Krupp; Monika Boecker; Fred Schambil
Original assignee: Henkel AG and Co KGaA
Current assignee: Individual
Priority date: 1999-04-23
Filing date: 2000-04-27
Publication date: 2000-10-29

Abstract

Detergent tablets containing 0.1 to 20% by weight of one or more binder compounds have advantageous performance properties, such as relatively high abrasion resistance and strength. The binder compounds contain 10 to 99% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g and 1 to 90% by weight of one or more non-surfactant liquid binders.

Description

Detergent Tablets Containing Binder Compound Field of the Invention This invention relates generally to compact shaped bodies having detersive properties. Such 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.
Thus, EP 687 464 (Allphamed Arzneimittel-Gesellschaft) describes effervescent tablets which consist of at least one active principle or a combination of active principles, at least one binder, optionally carriers such as flavors, dyes, perfumes, plasticizers, bleaching agents and effervescent additives, the binders) used being propylene glycol or glycerol, preferably in quantities of 0.004 to 2.5% by weight. Processes for producing these effervescent tablets are also claimed. According to the disclosure of this document, it is also possible through the teaching of the invention to produce an effervescent detergent tablet without the binder used leading to a loss of carbon dioxide from the effervescent additives.
European patent application EP 711 828 (Unilever) describes detergent tablets containing surfactant(s), builders) and a polymer which acts as a binder 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 solid polyethylene glycols is also described in German patent application DE 197 09 411.2 (Henkel). This document teaches synergistic effects between the polyethylene 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 the addition of 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 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.
Now, the problem addressed by the present invention was to provide tablets which, for predetermined hardness, would be distinguished by short disintegration times and which, 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, thus minimizing dosing and tabletting problems.
Summary of the Invention It has now been found that the addition of binder compounds of non-surfactant liquid binders and carriers with a high oil adsorption capacity to detergent premixes results in tablets which are distinctly more abrasion-resistant and considerably less friable than the hitherto known tablets. The use of the additives mentioned has little effect, if any, on the fracture resistance of the detergent tablets. Problems during the tabletting process, i.e. the "exudation" of the liquid binder into the die, are also avoided by this addition.
The present invention relates to detergent tablets of compacted particulate detergent containing surfactant(s), builders) and optionally other typical detergent ingredients, characterized in that, based on tablet weight, they contain 0.1 to 20% by weight of one or more binder compounds of a) 10 to 99% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g and b) 1 to 90% by weight of one or more non-surfactant liquid binders.
Detailed Description of the Invention In the context of the present invention, binder compounds are understood to be mixtures with the composition mentioned above which, basically, are present in the form of fine powders. If desired, these fine powders may be converted into a coarser form by spray drying, granulation, agglomeration, compacting, pelleting or extrusion processes.
The powder-form carrier materials present in the binder compounds in accordance with the invention have oil adsorption capacities above 20 grams per 100 g. The oil adsorption capacity is a physical property of a substance which can be measured by standardized methods. For example, British Standards BS1795 and BS3483:Part B7:1982, which both refer to IS0 78715, are available. In these test methods, a weighed sample of the particular substance is applied to a dish and refined linseed oil 5 (density: 0.93 gcm-3) is added dropwise from a burette. After each addition, the powder is intensively mixed with the oil using a spatula, the addition of oil being continued until a paste of flexible consistency is obtained. This paste should flow without crumbling. Now, the oil adsorption capacity is the quantity of oil added dropwise, based on 100 g of adsorbent, and is expressed in ml/100 g or g/100 g, conversions via the density of the linseed oil readily being possible. According to the invention, various compounds which may emanate both from the group of covalent compounds and from the group of salts are suitable as powder-form components. As already mentioned, the powder-form components preferably have even higher oil adsorption capacities, so that preferred detergent tablets are those in which the carrier materials) has/have an oil adsorption capacity of more than 25 g per 100 g, preferably more than 30 g per 100 g, more preferably more than 50 g per 100 g and most preferably more than 75 g per 100 g.
Examples of suitable substances are silicates, aluminium silicates and silicas which are described in detail hereinafter.
The expression "non-surfactant binder" in the context of the present invention characterizes binders which do not belong to the class of surfactants. The expression "liquid binder" refers to the aggregate state of the binder at 25°C/1013.25 mbar. Accordingly, substances which only melt or soften at higher temperatures are unsuitable for the purposes of the present invention.
Preferred quantities in which the binder compounds) is/are used lie within a relatively narrow range, so that preferred detergent tablets contain from 0.5 to 15% by weight, preferably from 1 to 10% by weight and more preferably from 2 to 7.5% by weight, based on tablet weight, of the binder compound(s).
The binder compounds per se present in accordance with the invention in the detergent tablets also preferably have a composition that lies within relatively narrow limits. In preferred detergent tablets according to the invention, the binder compounds) contains) - based on the compound -a) 20 to 90% by weight, preferably 30 to 80% by weight, more preferably 40 to 70% by weight and most preferably 40 to 60% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g, b) 10 to 80% by weight, preferably 20 to 70% by weight, more preferably 30 to 60% by weight and most preferably 40 to 60% by weight of one or more non-surfactant liquid binders.
The binder compounds present in accordance with the invention in the detergent tablets contain binders) applied to carrier materials.
According to the invention, the carrier materials used are substances with an oil adsorption capacity of more than 20 g per 100 g, the values of preferred carrier materials being well above that value. In preferred detergent tablets, the carrier materials) is/are selected from the group of silicas, alkali metal silicates and alkali metal aluminium silicates. _ Alkali metal silicates and alkali metal 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 m2/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 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 binder compounds.
Suitable non-surfactant liquid binders in the context of the present invention are any of a number of substances providing they do not belong to the group of surfactants and are liquid at 25°C/normal pressure.
Preferred binders are diols, such as ethanediol (ethylene glycol, glycol), 1,2-propanediol, 1,3-propanediol, 1,2-, 1,3-, 2,3- and 1,4-butanediol, 1,2-and 1,5-pentanediol, and also polyethylene glycols and polypropylene glycols, triols, such as glycerol and 1,2,6-hexanetriol, polyols liquid under the conditions mentioned, carbonic acid esters, such as propylene carbonate or glycerol carbonate, and paraffin oil. Accordingly, preferred detergent tablets are characterized in that the non-surfactant liquid binders) is/are selected from the group of diols, triols and polyols, carbonic acid esters and paraffin oils.
In preferred detergent tablets, compounds containing water-soluble binders are used as binder compounds. "Water-soluble" binders in the context of the present invention are binders which are miscible with water at room temperature. These substances are, for example, the above-mentioned diols, such as ethanediol (ethylene glycol, glycol), 1,2-propanediol, 1,3-propanediol, 1,2-, 1,3-, 2,3- and 1,4-butanediol, 1,2- and 1,5-pentanediol, and also polyethylene glycols and polypropylene glycols, triols, such as glycerol and 1,2,6-hexanetriol, polyols liquid under the conditions mentioned, carbonic acid esters, such as propylene carbonate or glycerol carbonate. In preferred detergent tablets according to the invention, the non-surfactant liquid binders) is/are selected from the group of polyethylene glycols and polypropylene glycols, glycerol, glycerol carbonate, ethylene glycol, propylene glycol and propylene carbonate.
Polyethylene glycols (PEGs) suitable for use in the binder compounds in accordance with the invention are polymers of ethylene glycol which correspond to general formula I:
H-(O-CH2-CH2)"-OH (I) in which n may assume a value of 1 (ethylene glycol, see below) to about 16. A factor of crucial importance in evaluating whether a polyethylene glycol is suitable for use in accordance with the invention is the aggregate state of the PEG at room temperature, i.e. the solidification point of the PEG must be below 25°C. Various nomenclatures are used for polyethylene glycols which can lead to confusion. It is common practice to indicate the mean relative molecular weight after the initials "PEG", so that "PEG 200" characterizes a polyethylene glycol having a relative molecular weight of about 190 to about 210. Under this nomenclature, the standard polyethylene glycols PEG 200, PEG 300, PEG 400 and PEG 600 may be used for the purposes of the present invention.
Cosmetic ingredients are covered by another nomenclature in which the initials PEG are followed by a hyphen and the hyphen is in turn directly followed by a number which corresponds to the index n in general formula I
above. Under this nomenclature (so-called INCI nomenclature, CTFA
International Cosmetic Ingredient Dictionary and Handbook, 5th Edition, The Cosmetic, Toiletry and Fragrance Association, Washington, 1997), PEG-4, PEG-6, PEG-$, PEG-9, PEG-10, PEG-12, PEG-14 and PEG-16, for example, may be used in accordance with the present invention.
Polyethylene glycols are commercially obtainable, for example under the trade names of Carbowax~ PEG 200 (Union Carbide), Emkapol~ 200 (ICI Americas), Lipoxol~ 200 MED (HULS America), Polyglycol~ E-200 (Dow Chemical), Alkapol~ PEG 300 (Rhone-Poulenc), Lutrol~ E300 (BASF) and the corresponding trade names with higher numbers.
Polypropylene glycols (PPGs) suitable for use in the binder compounds in accordance with the invention are polymers of propylene glycol which correspond to general formula II:
H-(O-C H-C H2) ~-O H ( I I ) in which n may assume a value of 1 (propylene glycol, see below) and about 12. Di-, tri- and tetrapropylene glycol, i.e. the representatives with n = 2, 3 and 4 in formula II, are of particular significance.
Glycerol is a colorless, clear, highly viscous, odorless and sweet-tasting hygroscopic liquid with a density of 1.261 which solidifies at 18.2°C.
Originally, glycerol was only a secondary product of the hydrolysis of fats, but is now industrially synthesized in large quantities. Most industrial processes start out from propene which is processed to glycerol via the 5 intermediate stages of allyl chloride and epichlorohydrin. Another industrial process is the hydroxylation of allyl alcohol with hydrogen peroxide on a W03 catalyst via the glycidol stage.
Glycerol carbonate can be obtained by transesterifying ethylene carbonate or dimethyl carbonate with glycerol, ethylene glycol or methanol 10 being obtained as secondary products. Another synthesis route starts out from glycidol (2,3-epoxy-1-propanol) which is reacted under pressure with C02 in the presence of catalysts to form glycerol carbonate. Glycerol carbonate is a clear, low-viscosity liquid with a density of 1.398 gcm-3 which boils at 125-130°C (0.15 mbar).
Ethylene glycol (ethane-1,2-diol, "glycol") is a colorless, viscous, sweet-tasting and highly hygroscopic liquid which is miscible with water, alcohols and acetone and which has a density of 1.113. The solidification point of ethylene glycol is -11.5°C; the liquid boils at 198°C.
Industrially, ethylene glycol is obtained from ethylene oxide by heating with water under pressure. Promising production processes can also be built up on the basis of the acetoxylation of ethylene and subsequent hydrolysis or on the basis of synthesis gas reactions.
Propylene glycol has two isomers, propane-1,3-diol and propane 1,2-diol. Propane-1,3-diol (trimethylene glycol) is a neutral, colorless and odorless, sweet-tasting liquid with a density of 1.0597 which solidifies at -32°C and boils at 214°C. Propane-1,3-diol can be produced from acrolein and water with subsequent catalytic hydrogenation.
Commercially by far the most important isomer is propane-1,2-diol (propylene glycol) which is an oily, colorless and almost odorless liquid with a density of 1.0381 which solidifies at -60°C and boils at 188°C. Propane 1,2-diol is produced from propylene oxide by water addition.
Propylene carbonate is a water-clear, low-viscosity liquid with a density of 1.2057 gcm-3 which melts at -49°C and boils at 242°C.
Propylene carbonate can also be industrially produced by reaction of propylene oxide and C02 at 200°C/80 bar.
Irrespective of the composition of the binder compounds, preferred detergent tablets are characterized in that their total content of non surfactant liquid binders is between 0.1 and 7.5% by weight, preferably between 0.25 and 5% by weight and more preferably between 0.5 and 3%
by weight, based on tablet weight.
Besides the binder 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. Other additives which are not normally used in detergents, but which can develop advantageous effects in tablets, are disintegration aids.
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" (6th 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 ~3-1,4-polyacetal of cellobiose which, in turn, is made up of two molecules of glucose. Suitable celluloses consist of ca. 500 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 98/40463 (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.
According to the invention, preferred detergent tablets aditionally contain a disintegration aid, preferably a cellulose-based disintegration aid, preferably in granular, co-granulated or compacted form, in quantities of 0.5 to 10% by weight, preferably in quantities of 3 to 7% by weight and more preferably in quantities of 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 NaMSiXO~+~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. Crystalline layer silicates such as these are described, for example, in European patent application EP-A-0 164 514. 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 ~3- and s-sodium disilicates Na2Si205y H20 are particularly preferred, ~i-sodium disilicate being obtainable, for example, by the process described in International patent application WO-A- 91/08171.
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 "amorphous" 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-5 ray amorphous silicates such as these, which also dissolve with delay in relation to conventional waterglasses, are described for 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.
10 The finely crystalline, synthetic zeolite containing bound water used in accordance with the invention is preferably zeolite A and/or zeolite P.
Zeolite 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-15 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 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 pm (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, Na2H2P207) 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 phenol-phthalein as indicator. Dipotassium hydrogen phosphate (secondary or dibasic potassium phosphate), KZHP04, 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 73-76° (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% P2O5). 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~, 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), K4P207, 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, K5P3O~p (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 5 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 10 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 15 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 20 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, 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 derivatives as monomers.
Other preferred copolymers are those which are described in German patent applications DE-A-43 03 320 and DE-A-44 17 734 and which preferably contain acrolein and acrylic acid/acrylic acid salts or acrolein and vinyl acetate 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, according to German patent application DE-A-195 40 086, are also said to have a bleach-stabilizing effect in addition to their co-builder properties.
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, terephthal-aldehyde and mixtures thereof and from polyol carboxylic acids, such as gluconic acid and/or glucoheptonic acid.
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. Dextrins thus oxidized and processes for their production are known, for example, from European patent applications EP-A-0 232 202, EP-A-0 42? 349, EP-A-0 472 042 and EP-A-0 542 496 and from International patent applications WO 92118542, WO 93108251, WO 93/16110, WO 94/28030, WO 95107303, WO 95112619 and WO 95120608. An oxidized oligosaccharide corresponding to German patent application DE-A-196 00 018 is also suitable. A product oxidized at Cs 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. Co-builders such as these are described, for example, in International patent application WO 95120029.
Another class of substances with co-builder properties are the phosphonates, more particularly hydroxyalkane and aminoalkane phos-phonates. 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).
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.
The anionic surfactants used are, for example, those of the sulfonate and sulfate type. Preferred surfactants of the sulfonate type are C9_~3 alkyl benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and hydroxy-alkane sulfonates, and the disulfonates obtained, for example, from C~2_~8 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_~8 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.
Other suitable anionic surfactants are sulfonated fatty acid glycerol esters, i.e. the monoesters, diesters and triesters and mixtures thereof which are obtained where production is carried out by esterification of a monoglycerol with 1 to 3 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 C6_22 fatty acids, 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 coconut alcohol, tallow alcohol, lauryl, myristyl, cetyl or stearyl alcohol, or C»2o 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 and C~2_~5 alkyl sulfates and also C~4_~5 alkyl sulfates are particularly preferred from the washing performance point of view. Other suitable anionic surfactants are 2,3-alkyl 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 5 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~Z_~8 fatty alcohols containing 1 to 4 EO, are also suitable. In view of their high foaming capacity, they are normally used in only relatively small quantities, for example in quantities of 1 to 5% by weight, in dishwashing 10 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, 15 ethoxylated fatty alcohols. Preferred sulfosuccinates contain C$_~8 fatty alcohol molecules or mixtures thereof. Particularly preferred sulfosuccinates contain a fatty alcohol molecule derived from ethoxylated fatty alcohols which, considered in isolation, represent nonionic surfactants (for a description, see below). Of these sulfosuccinates, those of which the 20 fatty alcohol molecules 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 25 soaps are, in particular, 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 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 group may be linear or, preferably, methyl-branched in the 2-position or may contain linear and methyl branched groups in the form of the mixtures typically present in oxoalcohol groups. However, alcohol ethoxylates containing linear groups 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 4 EO, C9_» alcohol containing 7 EO, C~~~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_~a 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.
Suitable other nonionic surfactants are alkyl glycosides with the general formula RO(G)X where R is a primary, linear or methyl-branched, more particularly 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 and preferably 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 especially the fatty acid methyl esters which are described, for example, in Japanese patent application JP 58/217598 or which are preferably produced by the process described in International patent application WO-A-90113533.
Nonionic surfactants of the amine oxide type, for example N
coconutalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxy ethylamine 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] (III) 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 (IV):

R' -O-R2 R-C O-N-[Z] ( I V) 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 polyhydroxy-alkyl 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, for example in accordance with the teaching of International patent application WO-A-95107331.
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 charac-terized 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 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 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 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, 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 perhy-drates and H202-yielding peracidic salts or peracids, such as perbenzoates, peroxophthalates, diperazelaic acid, phthaloiminoperacid or diperdodecane dioic acid. Where bleaching agents are used, it is again 5 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, 10 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) 15 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-carboxybenzamidoperoxy-20 caproic acid, N-nonenylamidoperadipic acid and N-nonenylamido persuccinates, 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-amino 25 percaproic 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, dibromo-30 isocyanuric 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-dihydrofuran.
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 cellobiohydrolases, endoglucanases and ~3-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 5 anionically and/or nonionically modified derivatives thereof. Of these, the 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 10 brighteners are, for example, salts of 4,4'-bis-(2-anilino-4-morpholino-1,3,5 triazinyl-6-amino)-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 15 alkali metal salts of 4,4'-bis-(2-sulfostyryl)-diphenyl, 4,4'-bis-(4-chloro-sulfostyryl)-diphenyl or 4-(4-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 20 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 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, 25 ether, aldehyde, ketone, alcohol and hydrocarbon type. Perfume com-pounds of the ester type are, for example, benzyl acetate, phenoxyethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl acetate, dimethyl benzyl carbinyl acetate, phenyl ethyl acetate, linalyl benzoate, benzyl formate, ethyl methyl phenyl glycinate, ally) cyclohexyl propionate, styrallyl 30 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, citronellyloxy-acetaldehyde, cyclamen aldehyde, 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 binder compounds of a) 10 to 99% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g and b) 1 to 90% by weight of one or more non-surfactant liquid binders.
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 premix contains the binder compounds) in quantities of 0.5 to 15% by weight, preferably in quantities of 1 to 10% by weight and more preferably in quantities of 2 to 7.5% by weight, based on the weight of the premix.
The foregoing observations also apply equally to preferred compositions of the binder compounds used in accordance with the invention. Accordingly, preferred processes are characterized in that the binder compounds contain - based on the compound -a) 20 to 90% by weight, preferably 30 to 80% by weight, more preferably 40 to 70% by weight and most preferably 40 to 60% by weight of one or more carrier materials with an oil adsorption capacity of more than g per 100 g, preferably more than 25 g per 100 g, more preferably 15 more than 30 g per 100 g, most preferably more than 50 g per 100 g and, in one particularly advantageous embodiment, more than 75 g per 100 g, the carrier materials preferably being selected from the group of silicas, alkali metal silicates and alkali metal aluminium silicates, b) 10 to 80% by weight, preferably 20 to 70% by weight, more preferably 20 30 to 60% by weight and most preferably 40 to 60% by weight of one or more non-surfactant liquid binders, preferably from the group of silicas, alkali metal silicates and alkali metal aluminium silicates, polyethylene glycols and polypropylene glycols, glycerol, glycerol carbonate, ethylene glycol, propylene glycol and propylene carbonate being particularly preferred.
In preferred variants of the process, the binder compounds also satisfy certain particle size criteria. Thus, preferred processes according to the invention are characterized in that at least 60% by weight, preferably at least 75% by weight and more preferably at least 90% by weight - based on the compound - of the binder compounds have particle sizes below 600 pm. In a particularly preferred embodiment, the binder compounds have a mean particle size below 400 Nm.
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, the premix to be tabletted 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 400 to 1600 Nm and most preferably 600 to 1400 Nm.
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 5 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 10 York/London/Sydney/Toronto, 1974, page 92). Besides zeolite X, there-fore, 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 15 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 20 components subsequently incorporated being a faujasite zeolite with particle sizes below 100 Nm, preferably below 10 Nm and more preferably below 5 Nm 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.
25 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, enzymes, pH regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, 30 optical brighteners, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors. These substances are described in the foregoing.
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 phases, namely metering, 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 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 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 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, 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 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 5 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 10 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.
15 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.
20 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 25 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.
30 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:
a=

~Dt where a represents the diametral fracture stress (DFS) in Pa, P is the force in N 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 binder compounds of a) 10 to 99% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g, b) 1 to 90% by weight of one or more non-surfactant liquid binders for improving the hardness and disintegration time and/or the abrasion resistance of detergent tablets. This use of the detergent compounds mentioned in accordance with the invention leads to tablets with advantageous properties, as the following non-limiting Examples show.
The foregoing observations on the process according to the invention apply equally to preferred embodiments of the use according to the invention (particle sizes, other ingredients, composition of the premix, etc.).
Examples Surfactant-containing granules (for composition, see Table 1 ), which were used as the basis for a particulate premix, were produced by granulation in a 5 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 (< 0.6 mm) and coarse particles (> 1.6 mm) were removed by sieving.
This premix was produced by mixing the surfactant-containing granules with bleaching agent, bleach activator and other additive components. 3% by weight of a binder compound of which the composition is shown in Table 2 were added to Example E according to the invention in the production of the premix so that the percentage amounts of the other components differ from those of Comparison Example C which contained no binder compound. Premixes E and C were tabletted in a Korsch eccentric press (tablet diameter 44 mm, tablet height 22 mm, tablet weight 37.5 g), no "exudation" of the binder from the tablet being observed. The composition of the premixes to be tabletted (and hence of the tablets) is shown in Table 3.
Table 1:
Composition of the surfactant granules [% by weight]
C9_~3 alkyl benzenesulfonate 18.6 C~2_~8 fatty alcohol + 7 EO 5.7 C~2_~8 fatty alcohol sulfate 5.4 Soap 1.6 Optical brightener 0.3 Sodium carbonate 16.6 Sodium silicate 5.4 Acrylic acid/maleic acid copolymer5.4 Zeolite A (water-free active 29.9 substance) Na hydroxyethane-1,1-diphosphonate0.8 Water, salts -- Balance J

Table 2:
Composition of the binder compound [% by weight]:
Overdried waterglass (sodium 57.5 silicate, amorphous, <10%
by weight water) Glycerol 42.5 Table 3:
Composition of the premixes [% by weight]
E C

Surfactant granules (Table 1) 64.5 65.8 Sodium perborate monohydrate 15.0 15.8 TAED 5.0 5.3 Foam inhibitor 3.0 3.2 Polyacrylate 1.0 1.0 Enzymes 2.0 2.1 Perfume 0.5 0.5 Wessalith~ P (zeolite A) 1.0 1.0 Disintegration aid (cellulose) 5.0 5.3 Binder compound 3.0 -The hardness of the tablets was measured 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 for the tablet to disintegrate completely was measured. The experi-mental data of the individual tablet series are shown in Table 4:

Table 4:
Detergent tablets containing binder compound [physical data]
Tablet E C

Tablet hardness [N] 34 36 Tablet disintegration [secs.]22 23 As can be seen from Table 4, the addition of the binder compound has hardly any influence on the fracture resistance or disintegration time of the laundry detergent tablets. In order to determine friability or abrasion behavior and brittle fracture behavior, tablets E according to the invention and comparison tablets C were introduced into a friabilator (rotating glass drum - diameter 180 mm, width 40 mm - which was provided with three triangular obstacle ribs - height 20 mm, base width 15 mm - extending transversely of the direction of rotation and arranged at equal intervals apart). At a rotational speed of 20 r.p.m., the time required for a tablet to break into several large parts was determined. The results of the measurements are shown in Table 5:
Table 5:
Results of the brittle fracture and friability measurements [s]
Fracture hardness26 N ~ 37 47 N
N

E 330 _ 1000 The data in Table 5 show that the effect of adding the binder compound is that, under mechanical load, the detergent tablets only break up into several parts much later, i.e. are more stable. In addition, the abrasion tendency of the tablets is distinctly reduced.

Claims

1. Detergent tablets of compacted particulate detergent containing surfactant(s), builder(s) and optionally other typical detergent ingredients, wherein said tablets contain 0.1 to 20% by weight, based on tablet weight, of one or more binder compounds of a) 10 to 99% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g and b) 1 to 90% by weight of one or more non-surfactant liquid binders.

2. Detergent tablets as claimed in claim 1, containing the binder compound(s) in quantities of 0.5 to 15% by weight based on tablet weight.

3. Detergent tablets as claimed in claim 2, containing the binder compound(s) in quantities of 1 to 10% by weight based on tablet weight.

4. Detergent tablets as claimed in claim 3, containing the binder compound(s) in quantities of 2 to 7.5% by weight based on tablet weight.

5. Detergent tablets as claimed in any one of claims 1 to 4, wherein the binder compound(s) contain(s) - based on the compound -a) 20 to 90% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g and b) 10 to 80% by weight of one or more non-surfactant liquid binders.

6. Detergent tablets as claimed in claim 5, wherein the binder compound(s) contain(s) 30 to 80% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g.

7. Detergent tablets as claimed in claim 6, wherein the binder compound(s) contain(s) 40 to 70% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g.

8. Detergent tablets as claimed in claim 7, wherein the binder compound(s) contain(s) 40 to 60% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g.

9. Detergent tablets as claimed in any one of claims 5 to 8, wherein the binder compound(s) contain(s) 20 to 70% by weight of one or more non-surfactant liquid binders.

10. Detergent tablets as claimed in claim 9, wherein the binder compound(s) contain(s) 30 to 60% by weight of one or more non-surfactant liquid binders.

11. Detergent tablets as claimed in claim 10, wherein the binder compound(s) contain(s) 40 to 60% by weight of one or more non-surfactant liquid binders.

12. Detergent tablets as claimed in any one of claims 1 to 11, wherein the carrier material(s) has/have an oil adsorption capacity of more than 25 g per 100 g.

13. Detergent tablets as claimed in claim 12, wherein the carrier material(s) has/have an oil adsorption capacity of more than 30 g per 100 g.

14. Detergent tablets as claimed in claim 13, wherein the carrier material(s) has/have an oil adsorption capacity of more than 50 g per 100 g.

15. Detergent tablets as claimed in claim 14, wherein the carrier material(s) has/have an oil adsorption capacity of more than 75 g per 100 9.

16. Detergent tablets as claimed in any one of claims 1 to 15, wherein the carrier material(s) is/are selected from the group of silicas, alkali metal silicates and alkali metal aluminium silicates.

17. Detergent tablets as claimed in any one of claims 1 to 16, wherein the non-surfactant liquid binder(s) is/are selected from the group of diols, triols and polyols, carbonic acid esters and paraffin oils.

18. Detergent tablets as claimed in any one of claims 1 to 17, wherein the non-surfactant liquid binder(s) is/are selected from the group of polyethylene glycols and polypropylene glycols, glycerol, glycerol carbonate, ethylene glycol, propylene glycol and propylene carbonate.

19. Detergent tablets as claimed in any one of claims 1 to 18, having a total non-surfactant liquid binder content of 0.1 to 7.5 % by weight based on tablet weight.

20. Detergent tablets as claimed in claim 19, having a total non-surfactant liquid binder content of 0.25 to 5 % by weight based on tablet weight.

21. Detergent tablets as claimed in claim 20, having a total non-surfactant liquid binder content of 0.5 to 3 % by weight based on tablet weight.

22. Detergent tablets as claimed in any one of claims 1 to 21, additionally containing a disintegration aid in quantities of 0.5 to 10% by weight based on tablet weight.

23. Detergent tablets as claimed in claim 22, additionally containing a disintegration aid in quantities of 3 to 7% by weight based on tablet weight.

24. Detergent tablets as claimed in claim 23, additionally containing a disintegration aid in quantities of 4 to 6% by weight based on tablet weight.

25. Detergent tablets as claimed in any one of claims 22 to 24, wherein the disintegration aid is cellulose-based.

26. Detergent tablets as claimed in claim 25, wherein the disintegration aid is in granular, co-granulated or compacted form.

27. Detergent tablets as claimed in any one of claims 1 to 26, containing anionic and/or nonionic surfactant(s) and having total surfactant contents above 2.5% by weight based on tablet weight.

28. Detergent tablets as claimed in claim 27, having total surfactant contents above 5 % by weight.

29. Detergent tablets as claimed in claim 28, having total surfactant contents above 10% by weight.

30. A process for the production of detergent tablets by tabletting a particulate premix in known manner, wherein the premix contains one or more binder compounds of a) 10 to 99% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g and b) 1 to 90% by weight of one or more non-surfactant liquid binders.

31. A process as claimed in claim 30, wherein the premix contains the binder compound(s) in quantities of 0.5 to 15% by weight based on the weight of the premix.

32. A process as claimed in claim 31, wherein the premix contains the binder compound(s) in quantities of 1 to 10% by weight based on the weight of the premix.

33. A process as claimed in claim 32, wherein the premix contains the binder compound(s) in quantities of 2 to 7.5% by weight based on the weight of the premix.

34.A process as claimed in any one of claims 30 to 33, wherein the binder compound(s) contain(s) - based on the compound-a) 10 to 90% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g, and b) 10 to 80% by weight of one or more non-surfactant liquid binders.

35. A process as claimed in claim 34, wherein the binder compound(s) contain(s) 30 to 80% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g.

36. A process as claimed in claim 35, wherein the binder compound(s) contain(s) 40 to 70% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g.

37. A process as claimed in claim 36, wherein the binder compound(s) contain(s) 40 to 60% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g.

38. A process as claimed in any one of claims 34 to 37, wherein the one or more carrier materials have an oil adsorption capacity of more than 25 g per 100 g.

39. A process as claimed in claim 38, wherein the one or more carrier materials have an oil adsorption capacity of more than 30 g per 100 g.

40. A process as claimed in claim 39, wherein the one or more carrier materials have an oil adsorption capacity of more than 50 g per 100 g.

41. A process as claimed in claim 40, wherein the one or more carrier materials have an oil adsorption capacity of more than 75 g per 100 g.

42. A process as claimed in any one of claims 34 to 41, wherein the carrier materials are selected from the group consisting of silicas, alkali metal silicates and alkali metal aluminium silicates.

43. Process as claimed in any one of claims 34 to 42, wherein the binder compounds contain 20 to 70% by weight of one or more non-surfactant liquid binders.

44. A process as claimed in claim 43, wherein the binder compounds contain 30 to 60% by weight of one or more non-surfactant liquid binders.

45. A process as claimed in claim 44, wherein the binder compounds contain 40 to 60% by weight of one or more non-surfactant liquid binders.

46. A process as claimed in any one of claims 43 to 45, wherein the the non-surfactant liquid binders are selected from the group consisting of silicas, alkali metal silicates and alkali metal aluminium silicates, polyethylene glycols and polypropylene glycols, glycerol, glycerol carbonate, ethylene glycol, propylene glycol and propylene carbonate.

47. A process as claimed in any one of claims 30 to 46, wherein at least 60% by weight of the binder compounds, based on the compound, consist of particles with particle sizes below 600 µm.

48. A process as claimed in claim 47, wherein at least 75% by weight of the binder compounds, based on the compound, consist of particles with particle sizes below 600 µm.

49. A process as claimed in claim 47, wherein at least 90% by weight of the binder compounds, based on the compound, consist of particles with particle sizes below 600 µm.

50. A process as claimed in any one of claims 47 to 49, wherein the binder compounds have a mean particle size below 400 µm.

51. A process as claimed in any of claims 30 to 50, wherein the particulate premix additionally contains surfactant-containing granules and has a bulk density of at least 500 g/l.

52. A process as claimed in claim 51, wherein the premix has a bulk density of at least 600 g/l.

53. A process as claimed in claim 52, wherein the premix has a bulk density of at least 700 g/l.

54. A process as claimed in any one of claims 51 to 53, wherein the surfactant-containing granules have particle sizes of 100 to 2000 µm.

55. A process as claimed in claim 54, wherein the surfactant-containing granules have particle sizes in the range of 200 to 1800 µm.

56. A process as claimed in claim 55, wherein the surfactant-containing granules have particle sizes in the range of 400 to 1600 µm.

57. A process as claimed in claim 56, wherein the surfactant-containing granules have particle sizes in the range of 600 to 1400 µm.

58. A process as claimed in any one of claims 51 to 57, wherein the surfactant-containing granules contain anionic and/or nonionic surfactants and builders and have total surfactant contents of at least 10% by weight.

59. A process as claimed in claim 58, wherein the surfactant-containing granules have total surfactant contents of at least 20% by weight.

60. A process as claimed in claim 59, wherein the surfactant-containing granules have total surfactant contents of at least 25% by weight.

61. A process as claimed in any of claims 30 to 60, wherein the particulate premix additionally contains one or more substances selected from the group consisting of bleaching agents, bleach activators, enzymes, pH regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, optical brighteners, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.

62. The use of binder compounds of a) 10 to 99% by weight of one or more carrier materials with an oil adsorption capacity of more than 20 g per 100 g and b) 1 to 90% by weight of one or more non-surfactant liquid binders for improving the hardness and disintegration time and/or the abrasion resistance of detergent tablets.