CA2298966A1 - Color-stable detergent tablets - Google Patents

Abstract

The color stability of completely or partly colored detergent tablets containing builders, bleaching agents and other ingredients typical of detergents and at least one dye unstable to bleaching agents can be distinctly improved if the areas of the tablet where the dye unstable to bleaching agents is present additionally contains paraffin. This color-stabilizing effect is particularly pronounced in phosphate-free and citrate-containing tablets.

Description

Color-stable Detergent Tablets Field of the Invention This invention relates to colored detergent tablets. More, particularly, the present invention relates to detergent tablets intended for use in dishwashing machines.
Background of the Invention Machine dishwashing detergents are widely described in the prior art. They normally contain one or more builders, bleaching agents, bleach activators, corrosion inhibitors and surfactants. In order to provide the consumer with a typical and unmistakable product, such detergents are normally perfumed and colored. The dyes used have to meet various requirements. They are expected to color the detergent permanently and in a visually noticeable manner, even in low concentrations, and should neither fade nor discolor, even after prolonged storage at elevated temperature. To this end, the dyes used have to be chemically inert to the partly aggressive ingredients (for example bleaching agents, alkalinity sources) and must not decompose either themselves or other ingredients.
Since commercially available detergent tablets are often two-colored for aesthetic reasons, no fading of the colored phase nor any migration of dye into lighter or uncolored areas should occur at the phase boundary between areas of different color.
The dyes are expected to satisfy stringent requirements in this regard. Although the detergents have to be contrastingly colored, the dye must not color either the dishwashing machine or the tableware to be cleaned, even in the event of prolonged use of one and the same detergent. Accordingly, the dyes must not have any pronounced substantivity towards metal or plastic surfaces. In addition, the dyes must be completely removed from the dishwashing machine in the rinse cycle and, after drainage, should not leave any films or colored lime stains behind on the tableware or in the machine. In addition, since the tableware _ CA 02298966 2000-02-18 is subsequently used for the preparation and storage of food, the dyes have to be toxicologically safe.
Earlier German patent application DE 198 21 695.5 (Henkel KGaA) describes the use of special dyes in detergents with a view to overcoming the problems mentioned above. The dyes mentioned in this document are also suitable for coloring laundry and dishwasher detergent tablets or individual areas of dishwasher tablets.
In tablets, the contact between dye and other dye-destabilizing ingredients (particularly bleaching agents) is so intimate that changes in color can occur in the event of prolonged storage, spoiling the appearance of the tablet. Where dyes are used above all in phosphate-free formulations where citrates are present as builders, the partly inadequate stability of the dyes to bleaching agents has proved to be a serious disadvantage. It has also been found in this connection that the logical separation of bleaching agent and dye into different areas of the tablet is not a solution in itself. Even if this measure is taken, fading and dye migration problems still occur at the phase boundary, leading to tablets of unacceptable appearance.
Now, the problem addressed by the present invention was to enable dyes unstable to bleaching agents to be used even in laundry and dishwasher detergent tablets without any of the disadvantages mentioned above having to be accepted. The above-mentioned requirement profile would be fully satisfied even - and above all - in phosphate-free and/or citrate-containing formulations.
Description of the Invention It has now been found that the addition of paraffin to the tablet or to that area of the tablet which contains the dye unstable to bleaching agents solves the problems mentioned above.
The present invention relates to laundry and dishwasher detergent tablets of compacted particulate detergent containing builders, bleaching agents and other typical detergent ingredients, characterized in that they contain at least one dye unstable to bleaching agents and in that the areas of the tablet containing the dye unstable to bleaching agents additionally contains paraffin.
Besides the constituents builder and bleaching agent and the dye unstable to bleaching agents, laundry and dishwasher detergent tablets according to the invention contain paraffin. Paraffin in the context of the present invention is the term used for a colorless, odorless and tasteless mixture of purified, saturated aliphatic hydrocarbons (paraffins). These alkane mixtures are commercially available and may be used in accordance with the present invention in various supply forms - from low-viscosity through relatively high-viscosity to paste-form or solid paraffin.
Low-viscosity paraffins normally have densities of 0.81 to 0.875 gcrri 3 and viscosities of 25 to 80 mPas whereas viscous paraffins have densities of 0.827 to 089 gcm-3 and viscosities of 110 to 230 mPas. Industrially, the liquid paraffins are often classed as mineral oils and are collectively referred to as paraffin oil or as white oil, the density of such products normally being at least 0.88 gcm-3 and their boiling point >360°C.
Semisolid paraffins with melting points of 45-65°C are known by such names as soft paraffin while those with densities of 0.82 to 0.88 gcm-3 and melting points of 38 to 60°C and boiling points of >300°C
are known by such names as petrolatum; a well-known trade mark for paraffins of this type is Vaseline. Hard paraffin (Paraffinum solidum) - a solid crystalline mass with a solidification temperature of 50 to 62°C - is also known.
According to the present invention, paraffin oils are particularly preferred. Preferred laundry and dishwasher detergent tablets according to the invention contain 0.1 to 5% by weight, preferably 0.25 to 4% by weight and more preferably 0.5 to 3% by weight of paraffin oil and/or paraffin wax, preferably low-viscosity paraffin oil.
The other ingredients compulsorily present in the tablets according to the invention are described in the following:
The builder present in the laundry and dishwasher detergent tablets according to the invention may be selected from any of the builders typically present in detergents, i.e. in particular zeolites, silicates, carbonates, organic cobuilders and also the phosphates.
Suitable crystalline layered sodium silicates correspond to the general formula NaMSiX02x+~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 layered silicates such as these are described, for example, in European patent application EP-A-0 164 514. Preferred crystalline layered silicates corresponding to the above formula are those in which M is sodium and x assumes the value 2 or 3. Both Vii- and 8-sodium disilicates Na2Si205y H20 are particularly preferred, (i-sodium disilicate being obtainable, for example, by the process described in International patent application WO-A- 91108171.
Other useful builders are amorphous sodium silicates with a modulus (NaZO: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-ray amorphous silicates such as these, which also dissolve with delay in relation to conventional waterglasses, are described for example in 5 German patent application DE-A-44 00 024. Compacted amorphous silicates, compounded amorphous silicates and overdried X-ray-amorphous silicates are particularly preferred.
The finely crystalline, synthetic zeolite containing bound water used in accordance with the invention is preferably zeolite A and/or zeolite P.
Zeolite 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 possible to use, for example, a co-crystallizate of zeolite X and zeolite A (ca. 80% by weight zeolite X) which is marketed by CONDEA Augusta S.p.A. under the name of VEGOBOND
AX~ and which may be described by the following formula:
nNa20 ~ (1-n)K20 ' AI2O3 ~ (2 - 2.5)Si02 ~ (3.5 - 5.5) H20.
The zeolite may be used both as a builder in a granular compound and for "powdering" the entire mixture to be tabletted, both these options normally being used to incorporate the zeolite in the premix. Suitable zeolites have a mean particle size of less than 10 ~m (volume distribution, as measured by the Coulter Counter Method) and contain preferably 18 to 22% by weight and more preferably 20 to 22% by weight of bound water.
The generally known phosphates may of course also be used as builders providing their use should not be avoided on ecological grounds.
The sodium salts of the orthophosphates, the pyrophosphates and, in particular, the tripolyphosphates are particularly suitable.
Useful organic builders are, for example, the polycarboxylic acids usable, for example, in the form of their sodium salts, such as citric acid, adipic acid, succinic acid, glutaric acid, tartaric acid, sugar acids, amino-carboxylic 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.
Alkalinity sources may be present as further ingredients. Alkalinity sources are alkali metal hydroxides, alkali metal carbonates, alkali metal hydrogen carbonates, alkali metal sesquicarbonates, alkali metal silicates, alkali metal metasilicates and mixtures of the substances mentioned above.
According to the invention, alkali metal carbonates, more particularly sodium carbonate, sodium hydrogen carbonate or sodium sesqui-carbonate, are preferably used.
Water-soluble builders are preferably used in dishwasher tablets according to the invention because, in general, they tend less to form insoluble residues on tableware and hard surfaces. Typical builders which may be present in dishwasher tablets according to the invention in quantities of 10 to 90% by weight, based on the premix to be tabletted, are the low molecular weight polycarboxylic acids and salts thereof, the homo-polymeric and copolymeric polycarboxylic acids and salts thereof, the car-bonates, phosphates and silicates. Trisodium citrate and/or pentasodium tripolyphosphate and/or sodium carbonate and/or sodium bicarbonate and/or gluconates and/or silicate builders from the class of disilicates and/or metasilicates are preferably used for the production of dishwasher tablets. A builder system containing a mixture of tripolyphosphate and sodium carbonate is particularly preferred. Another particularly preferred builder system contains a mixture of tripolyphosphate and sodium carbonate and sodium disilicate.
According to the invention, preferred detergent tablets are characterized in that they contain 20 to 95% by weight, preferably 30 to 90% by weight and more preferably 40 to 85% by weight of one or more builders from the group of phosphates, more particularly pentasodium tripolyphosphate, silicates, more particularly disilicates and/or metasilicates, zeolites, carbonates and/or hydrogen carbonates, low molecular weight polycarboxylic acids and salts thereof, more particularly citrates, homo- or copolymeric polycarboxylic acids and salts thereof and gluconates.
The incorporation of paraffin in the tablet or in that part of the tablet where the dye unstable to bleaches is present in accordance with the invention has particular advantages when the builder system contains citrates and is free from phosphates. In tablets such as these, the problems solved by the invention would otherwise come very clearly to light. According to the invention, preferred detergent tablets contain no phosphates.
As mentioned above, it is of advantage to use citrate-carbonate builder systems in dishwasher tablets. Accordingly, preferred detergent tablets are characterized in that they contain as builder 5 to 40% by weight, preferably 10 to 35% by weight and more preferably 15 to 30% by weight of one or more alkali metal citrates, preferably trisodium citrate dehydrate, and 5 to 50% by weight, preferably 10 to 45% by weight and more preferably 15 to 40% by weight of one or more alkali metal carbonates and/or hydrogen carbonates, preferably sodium hydrogen carbonate.
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. Even where bleaching agents are used, there is no need for surfactants and/or builders so that pure bleaching tablets can be produced. If such bleaching tablets are to be used for washing laundry, sodium percarbonate is preferably used, irrespective of which other ingredients are present in the tablets. If detergent or bleaching tablets for dishwashing machines are being produced, bleaching agents from the group of organic bleaches may also be used. Typical organic bleaching agents are diacyl peroxides, such as dibenzoyl peroxide for example.
Other typical organic bleaching agents are the peroxy acids, of which alkyl peroxy acids and aryl peroxy acids are particularly mentioned as examples.
Preferred representatives are (a) peroxybenzoic acid and ring-substituted derivatives thereof, such as alkyl peroxybenzoic acids, but also peroxy-a-naphthoic acid and magnesium monoperphthalate, (b) aliphatic or substituted aliphatic peroxy acids, such as peroxylauric acid, peroxystearic acid, e-phthalimidoperoxycaproic acid [phthaoiminoperoxyhexanoic acid (PAP)), o-carboxybenzamidoperoxycaproic acid, N-nonenylamidoperadipic acid and N-nonenylamidopersuccinates, and (c) aliphatic and araliphatic peroxydicarboxylic acids, such as 1,12-diperoxycarboxylic acid, 1,9-diperoxyazelaic acid, diperoxysebacic acid, diperoxybrassylic acid, diperoxyphthalic acids, 2-decyldiperoxybutane-1,4-dioic acid, N,N-terephthaloyl-di(6-aminopercaproic acid).
Other suitable bleaching agents in tablets for dishwashing machines 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, tribromo isocyanuric acid, dibromoisocyanuric acid and/or dichloroisocyanuric acid (DICA) and/or salts thereof with cations, such as potassium and sodium.
Hydantoin compounds, such as 1,3-dichloro-5,5-dimethyl hydantoin, are also suitable.
According to the invention, preferred detergent tablets are characterized in that the bleaching agent is selected from the groups of oxygen bleaching agents, more particularly sodium perborate monohydrate, sodium perborate tetrahydrate and sodium percarbonate, and/or halogen bleaching aents, more particularly chlorine bleaching agents, of which trichlorocyanuric acids, dichloro- and monochlorocyanurates and hypochlorites are particularly preferred.
Besides builder(s), bleaching agents) and paraffin, the detergent tablets according to the invention (or parts thereof) contain one or more dyes) unstable to bleaching agents as a fourth key constituent.
Corresponding dyes suitable for coloring detergents are dyes soluble in solvents and/or binders. In view of the structural diversity of these dyes (for example azo, azine, anthraquinone, acridine, cyanine, oxazine, polymethine, thiazine, triarylmethane dyes, etc.), several thousand different dyes are known, of which around 5,000 are commercially available and only around 500 are produced in industrial quantities. The dyes are systematically categorized not only according to their structure, but also under the so-called Colour Index with its number system (C.I. xxxx) or word/number system (Acid Red xxx). In the case of dyes which have been broadly adopted, the made-up names and trade names registered as trade marks may also be used for characterization.
Dyes used in laundry detergent and dishwasher tablets should have high stability in storage, should not be affected by the other ingredients of the detergent or by light and should not show pronounced substantivity towards textile fibers or tableware so as not to color them. In dishwasher tablets, the dyes mentioned in the prior art literature cited at the beginning -whose stability to bleaching agents has been improved in accordance with the invention - have proved to be suitable dyes. Specific examples of these dyes are Ponceau 4R (CAS No. 2611-82-7, C.I. 16255), Allura Red 40 (CAS No. 25956-17-6, CI 16035), Aluminium Rot RLW (CI Mordant Red 83), Supranol~ Rot GW (CAS No. 61901-44-8), Basantol~ Rot 310 (CAS No. 61951-36-8), Basacid~ Grun 970 (CAS-No. 19381-50-1), Supranol~ Grun 6 GW (anthraquinone dye preparation containing Acid Green 81), Supranol~ Griin BW (anthraquinone dye preparation containing Acid Green 84), Ultramarinblau-6394 (CAS No. 57455-37-5, CI
77007), Acid Yellow 17 (CAS No. 6359-98-4, CI 18965) and Acid Yellow 23 (CAS No. 1934-21-0, CI 19140).
The quantities in which the dyes are used in the laundry and 5 dishwashing detergent tablets according to the invention may vary according to the required color impression and the particular application envisaged. Preferred laundry and dishwashing detergent tablets according to the invention contain the dyes) unstable to bleaching agents in quantities of 0.01 to 1 % by weight, preferably 0.02 to 0.5% by weight and 10 more preferably 0.05 to 0.25% by weight, based on the tablet.
Besides the ingredients mentioned, the laundry and dishwashing detergent tablets according to the invention may contain other ingredients emanating in particular from the groups of bleach activators, disintegration aids, surfactants, enzymes, silver protectors, perfumes, polymers, pH
regulators, fluorescers, foam inhibitors, redeposition inhibitors, optical brighteners, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors and mixtures thereof.
In order to obtain an improved bleaching effect where washing is carried out at temperatures of 60°C or lower, bleach activators may be incorporated in the detergent tablets. The bleach activators may be compounds which form aliphatic peroxocarboxylic acids containing preferably 1 to 10 carbon atoms and more preferably 2 to 4 carbon atoms and/or optionally substituted perbenzoic acid under perhydrolysis conditions. Substances bearing O- and/or N-acyl groups with the number of carbon atoms mentioned and/or optionally substituted benzoyl groups are suitable. Preferred bleach activators are polyacylated alkylene-diamines, more particularly tetraacetyl ethylenediamine (TAED), acylated triazine derivatives, more particularly 1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine (DADHT), acylated glycolurils, more particularly tetraacetyl glycoluril (TAGU), N-acylimides, more particularly N-nonanoyl succinimide (NOSI), acylated phenol sulfonates, more particularly n-nonanoyl or isononanoyloxybenzenesulfonate (n- or iso-NOBS), carboxylic anhydrides, more particularly phthalic anhydride, acylated polyhydric alcohols, more particularly triacetin, ethylene glycol diacetate and 2,5-diacetoxy-2,5-dihydrofuran.
In addition to or instead of the conventional bleach activators mentioned above, 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, manganese-, iron-, cobalt-, ruthenium- or molybdenum-salen complexes or carbonyl complexes. Manganese, iron, cobalt, ruthenium, molybdenum, titanium, vanadium and copper complexes with nitrogen-containing tripod ligands and cobalt-, iron-, copper- and ruthenium-ammine complexes may also be used as bleach catalysts.
Preferred laundry and dishwashing detergent tablets according to the invention additionally contain a bleach activator, preferably from the group of polyacylated alkylenediamines, more particularly tetraacetyl ethylenediamine (TAED), N-acyl imides, more particularly N-nonanoyl succinimide (NOSI), acylated phenol sulfonates, more particularly n-nonanoyl or isononanoyloxybenzenesulfonate (n- or iso-NOBS), MMA
and/or the group of manganese and/or cobalt salts and/or complexes, more preferably the cobalt (ammine) complexes, cobalt (acetate) complexes, cobalt (carbonyl) complexes, chlorides of cobalt or manganese and manganese sulfate, preferably in quantities of 1 % by weight to 10% by weight and more preferably in quantities of 2% by weight to 8% by weight, based on the tablet weight.
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 ~i-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 98140463 (Henkel). Further particulars of the production of granulated, compacted or co-granulated cellulose disintegrators can also be found in these patent applications. The particle sizes of such disintegration aids is mostly above 200 Nm, at least 90% by weight of the particles being between 300 and 1600 arm 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 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 Nm.
Besides the builders mentioned above, the premix may also contain the detersive substances already mentioned which are particularly important ingredients for laundry detergent tablets. Depending on the tablet to be produced, different anwers are possible to the questions of whether to use surfactants and, if so, which surfactants. Normally, laundry detergent tablets may contain various surfactants from the groups of anionic, nonionic, cationic and amphoteric surfactants whereas dishwasher tablets preferably contain only low-foaming surfactants and water softening tablets and bleach tablets are free from surfactants. So far as the incorporation of the surfactants in the premix to be tabletted is concerned, there are no basic requirements to restrict the freedom of formulation.
Suitable anionic surfactants are, for example, those of the sulfonate and sulfate type. Suitable surfactants of the sulfonate type are preferably C9_~3 alkyl benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and hydroxyalkane sulfonates, and the disulfonates obtained, for example, from C~2-~s monoolefins with an internal or terminal double bond by sulfonation with gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of the sulfonation products. Other suitable surfactants of the sulfonate type are the alkane sulfonates obtained from C~2_~$ alkanes, for example by sulfochlorination or sulfoxidation and subsequent hydrolysis or neutralization. The esters of a-sulfofatty acids (ester sulfonates), for example the a-sulfonated methyl esters of hydrogenated coconut oil, palm kernel oil or tallow fatty acids, are also suitable.

Other suitable anionic surfactants are sulfonated fatty acid glycerol esters. Fatty acid glycerol esters in the context of the present invention are the monoesters, diesters and triesters and mixtures thereof which are obtained where production is carried out by esterification of a monoglycerol 5 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 fatty acids containing 6 to 22 carbon atoms, for example caproic acid, caprylic acid, capric acid, myristic acid, lauric acid, palmitic acid, stearic acid or behenic acid.
10 Preferred alk(en)yl sulfates are the alkali metal salts and, in particular, the sodium salts of the sulfuric acid semiesters of C~Z_~8 fatty alcohols, for example cocofatty alcohol, tallow fatty alcohol, lauryl, myristyl, cetyl or stearyl alcohol, or C~0.2o oxoalcohols and the corresponding semiesters of secondary alcohols with the same chain length. Other 15 preferred alk(en)yl sulfates are those with the chain length mentioned which contain a synthetic, linear alkyl chain based on a petrochemical and which are similar in their degradation behavior to the corresponding compounds based on oleochemical raw materials. C~2_,6 alkyl sulfates, C~2_~5 alkyl sulfates and C~4_~5 alkyl sulfates are preferred from the point of view of washing technology. Other suitable anionic surfactants are 2,3-alkyl sulfates which may be produced, for example, in accordance with US
3,234,258 or US 5,075,041 and which are commerially obtainable as products of the Shell Oil Company under the name of DAN~.
The sulfuric acid monoesters of linear or branched C~_2~ alcohols ethoxylated with 1 to 6 moles of ethylene oxide, such as 2-methyl-branched Cø> > alcohols containing on average 3.5 moles of ethylene oxide (EO) or C~2_~$ fatty alcohols containing 1 to 4 EO, are also suitable. In view of their high foaming capacity, they are only used in relatively small quantities, for example in quantities of 1 to 5% by weight, in dishwashing detergents.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic ~

acid which are also known as sulfosuccinates or as sulfosuccinic acid esters and which represent monoesters and/or diesters of sulfosuccinic acid with alcohols, preferably fatty alcohols and, more particularly, ethoxylated fatty alcohols. Preferred sulfosuccinates contain C$_~8 fatty alcohol residues or mixtures thereof. Particularly preferred sulfosuccinates contain a fatty alcohol residue derived from ethoxylated fatty alcohols which, considered in isolation, represent nonionic surfactants (for a description, see below). Of these sulfosuccinates, those of which the fatty alcohol residues are derived from narrow-range ethoxylated fatty alcohols are particularly preferred. Alk(en)yl succinic acid preferably containing 8 to 18 carbon atoms in the alk(en)yl chain or salts thereof may also be used.
Other suitable anionic surfactants are, in particular, soaps. Suitable soaps are saturated fatty acid soaps, such as the salts of lauric acid, myristic acid, palmitic acid, stearic acid, hydrogenated erucic acid and behenic acid, and soap mixtures derived in particular from natural fatty acids, for example coconut oil, palm kernel oil or tallow fatty 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.
According to the invention, preferred detergents tablets are those in which the surfactant granules contain 5 to 45% by weight, preferably 10 to 40% by weight and more preferably 15 to 35% by weight of anionic surfactants, based on the weight of the surfactant granules.
So far as the choice of anionic surfactants is concerned, there are no basic requirements to restrict the freedom of formulation. However, preferred surfactant granules do have a soap content in excess of 0.2% by weight, based on the total weight of the detergent tablets. Preferred anionic surfactants are alkyl benzenesulfonates and fatty alcohol sulfates, ' CA 02298966 2000-02-18 preferred detergent tablets containing 2 to 20% by weight, preferably 2.5 to 15% by weight and more preferably 5 to 10% by weight of fatty alcohol sulfate(s), based on the weight of the detergent composition.
Preferred nonionic surfactants are alkoxylated, advantageously ethoxylated, more especially primary alcohols preferably containing 8 to 18 carbon atoms and, on average, 1 to 12 moles of ethylene oxide (EO) per mole of alcohol, in which the alcohol component may be linear or, preferably, methyl-branched in the 2-position or may contain linear and methyl-branched residues in the form of the mixtures typically present in oxoalcohol residues. However, alcohol ethoxylates containing linear residues of alcohols of native origin with 12 to 18 carbon atoms, for example coconut oil, palm oil, tallow fatty or oleyl alcohol, and on average 2 to 8 EO per mole of alcohol are particularly preferred. Preferred ethoxylated alcohols include, for example, C~2-14 alcohols containing 3 EO
or 4 EO, C9_» alcohol containing 7 EO, C~3_~5 alcohols containing 3 EO, 5 EO, 7 EO or 8 EO, C~2_~8 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_~$ 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.
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 581217598 ' CA 02298966 2000-02-18 or which are preferably produced by the process described in International patent application WO-A-90113533.
Another class of nonionic surfactants which may advantageously be used are the alkyl polyglycosides (APGs). Suitable alkyl polyglycosides correspond to the general formula RO(G)Z where R is a linear or branched, more particularly 2-methyl-branched, saturated or unsaturated 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 glycosidation z is between 1.0 and 4.0, preferably between 1.0 and 2.0 and more preferably between 1.1 and 1.4.
Linear alkyl polyglucosides, i.e. alkyl polyglycosides in which the polyglycosyl component is a glucose unit and the alkyl component is an n-alkyl group, are preferably used.
The detergent tablets according to the invention may advantageously contain alkyl polyglycosides, APG contents of more than 0.2% by weight, based on the tablet as a whole, being preferred.
Particularly preferred detergent tablets contain APGs in quantities of 0.2 to 10% by weight, preferably in quantities of 0.2 to 5% by weight and more preferably in quantities of 0.5 to 3% by weight.
Nonionic surfactants of the amine oxide type, for example N-cocoalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxyethyl-amine 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 (I):
R' R-CO-N-[Z] (I) ~

in which RCO is an aliphatic acyl group containing 6 to 22 carbon atoms, R' is hydrogen, an alkyl or hydroxyalkyl group containing 1 to 4 carbon atoms and [Z] is a linear or branched polyhydroxyalkyl group containing 3 to 10 carbon atoms and 3 to 10 hydroxyl groups. The polyhydroxyfatty acid amides are known substances which may normally be obtained by reductive amination of a reducing sugar with ammonia, an alkylamine or an alkanolamine and subsequent acylation with a fatty acid, a fatty acid alkyl ester or a fatty acid chloride.
The group of polyhydroxyfatty acid amides also includes compounds corresponding to formula (II):
R'-O-R2 R-CO-N-[Z] (I I) 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-95/07331.
In principle, any surfactants may also be used as surfactants in the " CA 02298966 2000-02-18 production of dishwasher tablets. However, the nonionic surfactants described above, above all low-foaming nonionic surfactants, are preferably used for this purpose. Alkoxylated alcohols, especially ethoxylated and/or propoxylated alcohols, are particularly preferred.
5 Alkoxylated alcohols are generally understood by the expert to be the reaction products of alkylene oxide, preferably ethylene oxide, with alcohols, the relatively long-chain alcohols (C~o to CAB, preferably between C~Z and Cps such as, for example, C», C~2, C~3, C~4, C~5, Cps, C~~ and C~8 alcohols) being preferred for the purposes of the present invention. In 10 general, a complex mixture of addition products differing in their degree of ethoxylation is formed from n moles of ethylene oxide and 1 mole of alcohol, depending on the reaction conditions. Another embodiment is characterized by the use of mixtures of alkylene oxides, preferably a mixture of ethylene oxide and propylene oxide. If desired, "end-capped"
15 alcohol ethoxylates, which may also be used in accordance with the invention, may also be obtained by etherification with short-chain alkyl groups, preferably butyl groups, in a concluding step. According to the invention, highly ethoxylated fatty alcohols or mixtures thereof with end capped fatty alcohol ethoxylates are particularly preferred for the purposes 20 of 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, 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.
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.
The enzymes may be adsorbed to supports and/or encapsulated in shell-forming substances to protect them against premature decomposition.
The percentage content of the enzymes, enzyme mixtures or enzyme granules in the tablets according to the invention may be, for example, from about 0.1 to 5% by weight and is preferably from 0.5 to about 4.5% by weight.
In laundry detergent tablets, cellulases may also be used in addition to the enzymes mentioned above. Cellulases and other glycosyl hydrolases can contribute towards color retention and towards increasing fabric softness by removing pilling and microfibrils. Preferred cellulases are cellobiohydrolases, endoglucanases and ~i-glucosidases, which are also known as cellobiases, and mixtures thereof. Since the various cellulase types differ in their CMCase and avicelase activities, the desired activities can be established by mixing the cellulases in the appropriate ratios.
If dishwasher tablets according to the invention are to be produced, they may contain corrosion inhibitors to protect the tableware or the machine itself, silver protectors being particularly important for dishwashing machines. Known corrosion inhibitors 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 ' CA 02298966 2000-02-18 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, hydroxy-hydroquinone, 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 prevent corrosion of to b lewa re.
Preferred laundry and dishwasher detergent tablets according to the invention additionally contain at least one silver protector selected from the group of triazoles, benzotriazoles, bisbenztotriazoles, aminotriazoles alkylamiotriazoles, preferably benzotriazole and/or alkylaminotriazole.
In addition, laundry detergent tablets according to the invention 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 hydroxy-propoxyl groups, based on the nonionic cellulose ether, and the polymers of phthalic acid and/or terephthalic acid known from the prior art or derivatives thereof, more particularly polymers of ethylene terephthalates and/or polyethylene glycol terephthalates or anionically and/or nonionically modified derivatives thereof. Of these, the sulfonated derivatives of phthalic acid and terephthalic acid polymers are particularly preferred.
If laundry detergent tablets are to be produced, the premix to be tabletted may contain derivatives of diamino-stilbenedisulfonic acid or alkali metal salts thereof as optical brighteners. Suitable optical brighteners are, for example, salts of 4,4'-bis-(2-anilino-4-morpholino-1,3,5-triazinyl-6 amino)-stilbene-2,2'-disulfonic acid or compounds of similar composition which contain a diethanolamino group, a methylamino group, an anilino group or a 2-methoxyethylamino group instead of the morpholino group.
Brighteners of the substituted diphenyl styryl type, for example alkali metal salts of 4,4'-bis-(2-sulfostyryl)-Biphenyl, 4,4'-bis-(4-chloro-3-sulfostyryl)-diphenyl or 4-(4-chlorostyryl)-4'-(2-sulfostyryl)-Biphenyl, may also be present. Mixtures of the brighteners mentioned above may also be used.
Perfumes may be added to the detergent tablets produced in accordance with 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 fragrances include individual fragrance compounds, for example synthetic products of the ester, ether, aldehyde, ketone, alcohol and hydrocarbon type. Fragrance compounds of the ester type are, for example, benzyl acetate, phenoxy-ethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl acetate, dimethyl benzyl carbinyl acetate, phenyl ethyl acetate, linalyl benzoate, benzyl formate, ethyl methyl phenyl glycinate, allyl cyclohexyl propionate, styrallyl propionate and benzyl salicylate. The ethers include, for example, benzyl ethyl ether; the aldehydes include, for example, the linear alkanals containing 8 to 18 carbon atoms, citral, citronellal, 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 fragrances which together produce an attractive fragrance note are preferably used. Perfume oils such as these may also contain natural fragrance 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 perfumes may be directly incorporated in the premix, 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.
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 metering, even at high tablet throughputs, is preferably achieved by volumetric metering 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 ' CA 02298966 2000-02-18 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 5 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 10 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.).
15 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 20 production volumes, it is preferred to use eccentric tablet presses in which the punches) is/are fixed to an eccentric disk 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, 25 although several punches can also be fixed to a single eccentric disk, 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.
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, KILIAN, Cologne, KOMAGE, Kell am See, KORSCH Pressen GmbH, Berlin, Mapag Maschinenbau AG, Bern (Switzerland) and Courtoy N.V., Halle (BE/LU). One example of a particularly suitable tabletting machine is the model HPF 630 hydraulic double-pressure press manufactured by LAEIS, D.
The tablets can be made in certain shapes and certain sizes.
Suitable shapes are virtually any easy-to-handle shapes, for example slabs, bars, cubes, squares and corresponding shapes with flat sides and, in particular, cylindrical forms of circular or oval cross-section. This last embodiment encompasses shapes from tablets to compact cylinders with a height-to-diameter ratio of more than 1.
The portioned pressings may be formed as separate individual elements which correspond to a predetermined dose of the detergent.
However, it is also possible to form pressings which combine several such units in a single pressing, smaller portioned units being easy to break off in particular through the provision of predetermined weak spots. For the use of laundry detergents in machines of the standard European type with horizontally arranged mechanics, it can be of advantage to produce the portioned pressings as cylindrical or square tablets, preferably with a diameter-to-height ratio of about 0.5:2 to 2:0.5. Commercially available hydraulic presses, eccentric presses and rotary presses are particularly suitable for the production of pressings such as these.
The three-dimensional form of another embodiment of the tablets according to the invention is adapted in its dimensions to the dispensing compartment of commercially available domestic washing machines, so that the tablets can be introduced directly, i.e. without a dosing aid, into the dispensing compartment where they dissolve on contact with water.
However, it is of course readily possible - and preferred in accordance with ' CA 02298966 2000-02-18 the present invention - to use the detergent tablets in conjunction with a dosing aid.
Another preferred tablet which can be produced has a plate-like or slab-like structure with alternately thick long segments and thin short segments, so that individual segments can be broken off from this "bar" at the predetermined weak spots, which the short thin segments represent, and introduced into the machine. This "bar" principle can also be embodied in other geometric forms, for example vertical triangles which are only joined to one another at one of their longitudinal sides.
In another possible embodiment, however, the various components are not compressed to form a single tablet, instead the tablets obtained comprise several layers, i.e. at least two layers. These various layers may have different dissolving rates. This can provide the tablets with favorable performance properties. If, for example, the tablets contain components which adversely affect one another, one component may be integrated in the more quickly dissolving layer while the other component may be incorporated in a more slowly dissolving layer so that the first component can already have reacted off by the time the second component dissolves.
The various layers of the tablets can be arranged in the form of a stack, in which case the inner layers) dissolve at the edges of the tablet before the outer layers have completely dissolved. Alternatively, however, the inner layers) may also be completely surrounded by the layers lying further to the outside which prevents constituents of the inner layers) from dissolving prematurely.
In another preferred embodiment of the invention, a tablet consists of at least three layers, i.e. two outer layers and at least one inner layer, a peroxy bleaching agent being present in at least one of the inner layers whereas, in the case of the stack-like tablet, the two cover layers and, in the case of the envelope-like tablet, the outermost layers are free from peroxy bleaching agent. In another possible embodiment, peroxy ' CA 02298966 2000-02-18 bleaching agent and any bleach activators 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 constitu ents 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 laundry and dishwasher 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.
As mentioned above, tablets according to the invention comprising several phases, preferably several layers, may also be produced.
Accordingly, the present invention also relates to multiphase laundry and dishwasher detergent tablets of compacted particulate detergent containing builders, bleaching agents, at least one dye unstable to bleaches and other typical ingredients, characterized in that the bleaching agents) and/or the dyes) unstable to bleaching agents are present in separate phases and in a CA 02298966 2000-02-18 that the phase containing the dye unstable to bleaching agents additionally contains paraffin. As already mentioned, multiphase detergent tablets in which the phases of the tablet are in the form of layers are preferred.
The above-mentioned ingredients and quantity ranges in which they 5 are used are also preferred for multiphase tablets. So far as the ingredients bleaching agent and dye are concerned, preferred multiphase laundry and dishwasher detergent tablets are those in which the bleach-containing phase contains 5 to 50% by weight, preferably 7.5 to 40% by weight and more preferably 10 to 30% by weight, based on the phase, of 10 bleaching agent and the dye-containing phase contains 0.01 to 2% by weight, preferably 0.05 to 15% by weight and more preferably 0.1 to 1.0%
by weight, based on the phase, of dye.
Embodiments of the present invention are described in the following Examples which are not to be construed as limiting.
Examples Two-layer dishwasher tablets (one third upper phase, two thirds lower phase) were produced by tabletting various premixes. First, the particular premix for the lower phase was introduced into the die of a commercial tablet press (Korsch TRP 700) and precompressed, after which the premix for the upper phase was introduced and the tabletting process completed.
The tablets E according to the invention differ from the comparison tablets C in that the colored layer (upper phase) additionally contains paraffin. The composition of the premixes to be compressed and hence the composition of the tablets is shown in the following Table:

E V

Upper Lower Upper Lower phase phase phase phase Sodium carbonate 19.0 - 19.0 -Sodium hydrogen carbonate 40.0 20.0 43.0 20.0 Trisodium citrate dehydrate24.0 55.0 24.0 55.0 Enzyme granules 13.4 - 13.4 -Perfume 0.4 - 0.4 -Dye* 0.2 - 0.2 -Paraffin oil 3.0 - - -Sodium perborate monohydrate- 15.0 - 15.0 Tetraacetyl ethylenediamine- 6.0 - 6.0 C~2 Fatty alcohol + 3E0 - 4.0 - 4.0 * Ponceau 4R (CI 16255):
7-Hydroxy-8-[(4-sulfo-1-naphthalenyl)azo]-1,3-naphthalenedisulfonic acid trisodium salt The tablets were visually evaluated immediately after production and after storage for one week. The results are set out in the following Table.

Tablet E C

Color of upper phaseBright red Bright red after production Color of upper phaseBright red, no changePale pink, lightened after 1 week's storage Phase boundary afterClean straight lineClean straight line production Phase boundary afterNo change Irregular: coloring 1 of week's storage lower phase, fading of upper phase Stability in storageGood Poor The use of the paraffin oil in the colored layer leads to better color stability and greater color brightness.

Claims (12)

1. A laundry and dishwasher detergent tablet of compacted particulate detergent containing builders, bleaching agents and other ingredients typical of such detergents, characterized in that it contains at least one dye unstable to bleaching agents and in that the areas of the tablet where the dye unstable to bleaching agents is present additionally contains paraffin.

2. A detergent tablet as claimed in claim 1, characterized in that it contains 20 to 95% by weight, preferably 30 to 90% by weight and more preferably 40 to 85% by weight of one or more builders from the group of phosphates, more particularly pentasodium tripolyphosphate, silicates, more particularly disilicates and/or metasilicates, zeolites, carbonates and/or hydrogen carbonates, low molecular weight polycarboxylic acids and salts thereof, more particularly citrates, homo- or copolymeric polycarboxylic acids and salts thereof and gluconates.

3. A detergent tablet as claimed in claim 1 or 2, characterized in that it is free from phosphates.

4. A detergent tablet as claimed in any of claims 1 to 3, characterized in that it contains as builder 5 to 40% by weight, preferably 10 to 35% by weight and more preferably 15 to 30% by weight of one or more alkali metal citrates, preferably trisodium citrate dehydrate, and 5 to 50% by weight, preferably 10 to 45% by weight and more preferably 15 to 40% by weight of one or more alkali metal carbonates and/or hydrogen carbonates, preferably sodium hydrogen carbonate.

5. A detergent tablet as claimed in any of claims 1 to 4, characterized in that the bleaching agent is selected from the groups of oxygen bleaching agents, more particularly sodium perborate monohydrate, sodium perborate tetrahydrate and sodium percarbonate, and/or halogen bleaching aents, more particularly chlorine bleaching agents, of which trichlorocyanuric acids, dichloro- and monochlorocyanurates and hypochlorites are particularly preferred.

6. A detergent tablet as claimed in any of claims 1 to 5, characterized in that it contains the dye unstable to bleaching agents in quantities of 0.01 to 1% by weight, preferably 0.02 to 0.5% by weight and more preferably 0.05 to 0.25% by weight, based on the tablet.

7. A detergent tablet as claimed in any of claims 1 to 6, characterized in that it contains 0.1 to 5% by weight, preferably 0.25 to 4% by weight and more preferably 0.5 to 3% by weight of paraffin oil and/or paraffin wax, preferably low-viscosity paraffin oil.

8. A multiphase laundry and dishwasher detergent tablet of compacted particulate detergent containing builders, bleaching agents, at least one dyes unstable to bleaching agents and other typical ingredients, characterized in that the bleaching agents(s) and/or the dye(s) unstable to bleaching agents are present in separate phases and in that the phase containing the dye unstable to bleaches additionally contains paraffin.

9. A multiphase detergent tablet as claimed in claim 8, characterized in that the phases of the tablet are in the form of layers.

10. A multiphase detergent tablet as claimed in claim 8 or 9, characterized in that the bleach-containing phase contains 5 to 50% by weight, preferably 7.5 to 40% by weight and more preferably 10 to 30% by weight, based on the phase, of bleaching agent and the dye-containing phase contains 0.01 to 2% by weight, preferably 0.05 to 15% by weight and more preferably 0.1 to 1.0% by weight, based on the phase, of dye.

11. A detergent tablet as claimed in any of claims 1 to 10, characterized in that they additionally contain a bleach activator, preferably from the group of polyacylated alkylenediamines, more particularly tetraacetyl ethylenediamine (TAED), N-acyl imides, more particularly N-nonanoyl succinimide (NOSI), acylated phenol sulfonates, more particularly n-nonanoyl or isononanoyloxybenzenesulfonate (n- or iso-NOBS), MMA
and/or the group of manganese and/or cobalt salts and/or complexes, more preferably the cobalt (ammine) complexes, cobalt (acetate) complexes, cobalt (carbonyl) complexes, chlorides of cobalt or manganese and manganese sulfate, preferably in quantities of 1% by weight to 10% by weight and more preferably in quantities of 2% by weight to 8% by weight, based on the tablet weight.

12. A detergent tablet as claimed in any of claims 1 to 11, characterized in that it additionally contains at least one silver protector selected from the group of triazoles, benzotriazoles, bisbenzotriazoles, aminotriazoles, alkylaminotriazoles, preferably benzotriazole and/or alkylamino triazole.