Dishwasher product in tablet form

The invention relates to a dishwasher detergent in the form of a multi-layer tablet comprising a bleach, a bleach activator, a silver/copper corrosion inhibitor and also other customary constituents, where the silver/copper corrosion inhibitor is not present together with the bleach and the bleach activator in one layer.

The present invention relates to a dishwasher detergent in the form of a
 tablet comprising a bleach and a bleach activator and also other customary
 constituents.
 Conventional detergents for the machine cleaning of dishes are generally
 pulverulent, granular or liquid products. Cleaning compositions in the
 form of tablets have likewise been known for some years. In principle,
 products in the form of tablets have a number of advantages over
 pulverulent and liquid products: they do not require accurate measurement
 of the amount to be used and are therefore easier to handle and introduce
 into the dishwasher, they are more compact and therefore require less
 packing material and storage space and they are safer to use in the
 household since spillage of the often aggressive substances is not
 possible.
 However, it has been found that cleaning compositions in tablet form can
 have a poorer cleaning action than those in powder form. This can be
 attributed to the fact that in pressed tablets the individual constituents
 are significantly more closely joined together than in, powders, so that
 negative interactions which individual constituents can exercise on one
 another can occur to a greater degree. But, partial inactivation of
 individual constituents can result. The applicant has now found that such
 a problem also occurs in the combined use of bleaches and bleach
 activators with silver/copper corrosion inhibitors.
 A further problem which occurs in the case of dishwasher detergents in
 tablet form and which impairs washing performance is that such dishwasher
 detergents are less effective than comparable powders, since the tablets
 dissolve more slowly and therefore are available in the washing liquor
 only later than when powders are used. This problem occurs particularly in
 the case of dishwasher detergents containing a bleach, since when said
 compositions are used in tablet form the concentration of the bleach
 necessary for bleaching is reached only relatively late in the washing
 process. As a solution to this problem, it is proposed in EP-A 504 091
 that a certain combination of alkali metal carbonate, polycarboxylate, a
 polyfunctional carboxylic acid, sodium silicate, a nonionic surfactant and
 the bleach be used so that the bleaching effect of the pressed tablets is
 retained.
 EP-A 634 478 discloses dishwasher detergents comprising nitrogen-containing
 corrosion inhibitors and an oxygen-liberating bleach. According to the
 statements of this document, the dishwasher detergents can be present in
 any form and tablets too are mentioned in passing, with the difficulties
 which can occur in the formulation of corrosion inhibitors with bleaches
 or bleach activators obviously not having been recognized.
 EP-A 481 547 discloses that during storage of a dishwasher detergent and in
 the aqueous cleaning solution in a dishwasher, enzymes are deactivated in
 the presence of a chlorine bleach. As a solution to this problem, EP-A 481
 547 discloses a dishwasher detergent comprising enzymes and chlorine
 bleaches in the form of a tablet having at least three layers and a
 complex structure, comprising an inner layer, a barrier layer and an outer
 layer. The enzymes and the chlorine bleaches are thus separated in various
 layers of the tablet. This complex structure of the cleaning composition
 tablets is supposed to ensure that, on the one hand, no interface exists
 during storage between the layer containing the chlorine bleach and the
 layer containing the enzyme and, on the other hand, the two layers are not
 dissolved simultaneously but rather are dissolved in succession and
 therefore the chlorine bleach and the enzyme are not simultaneously
 present in the washing water of the dishwasher.
 EP-A 1481 793 discloses cleaning compositions in tablet form which contain
 sodium percarbonate as bleach and are to be used in textile washing
 machines. In order to be able to obtain a storage-stable tablet which
 comprises not only sodium percarbonate but also other constituents which
 can interact with the bleach, it is proposed that percarbonate be
 separated in the tablet from the other constituents, for example in two
 layers. The tablets thus produced are, in addition, said to have an
 increased dissolution rate in the washing liquor.
 EP-A 481 792 discloses a product in tablet form for the treatment of
 fabrics in washing machines, which product comprises, to improve the
 bleaching action, a combination of a per-salt and a bleach activator, with
 the bleach activator having to have a certain rate constant for the
 hydrolysis of the per-salt.
 DE-A 25 27 534 discloses a multilayer cleaning tablet for dentures, with
 the first layer containing an enzyme and dissolving before the second
 layer containing active oxygen. By this means the enzyme can act at first
 without being deactivated by the active oxygen liberated.
 It is an object of the present invention to provide a dishwasher detergent
 in the form of a tablet which comprises not only a bleach, a bleach
 activator and other customary constituents but also a silver/copper
 corrosion inhibitor which prevents the tarnishing of nonferrous metals on
 the dishes to be cleaned, with the silver/copper corrosion inhibitor not
 impairing the effectiveness of the tablet, but giving at least as good a
 washing performance as in the case of a comparable powder, preferably even
 better.
 It is a further object of the invention to provide a dishwasher detergent
 in the form of a tablet which comprises not only a bleach, a bleach
 activator and other customary constituents but also a silver/copper
 corrosion inhibitor which prevents the tarnishing of nonferrous metals on
 the dishes to be cleaned, with the composition, although it is in tablet
 form and the individual constituents of the washing liquor are therefore
 available only in a later stage of the washing process, displaying a
 washing performance which is at least as good, preferably better, as that
 of the composition in powder form.
 It has now surprisingly been found that tablets which consist of at least
 two layers and in which the silver/copper corrosion inhibitor is not
 present together with the bleach and the activator in one layer have an
 undiminished or even improved cleaning action compared with powders of the
 same composition, despite the fact that the tablet dissolves only during
 the course of the washing process and the constituents of the composition
 are therefore available only in a later stage of the washing process.
 Furthermore, these effects occur not only in dishwasher detergents after a
 certain storage time, but surprisingly also in dishwasher detergents
 directly after manufacture, so that the effects occur independently of
 interactions which can take place in the composition during storage.
 The present invention accordingly provides a dishwasher detergent in the
 form of a tablet comprising a bleach, a bleach activator and other
 customary constituents and additionally contains a silver/copper corrosion
 inhibitor, where the tablet consists of at least two layers and the
 silver/copper corrosion inhibitor is not present together with the bleach
 and the bleach activator in one layer.
 Preferably, the tablet of the invention does not dissolve completely in the
 liquor of the dishwasher in less than three minutes.
 For the purposes of the present invention, "dissolve completely" means that
 the tablets have disintegrated to the extent that in agitated water at
 40.degree. C. they can pass through a basket having 4 mm openings.
 The bleaches present in the dishwasher detergents of the invention are
 preferably chlorine-free bleaches which liberate active oxygen, for
 example inorganic perhydrates or organic peracids and their salts.
 Examples of inorganic perhydrates are perborates, percarbonates and
 persulfates such as peroxo monopersulfates. The inorganic perhydrates are
 normally alkaline metal salts such as lithium, sodium, potassium, or
 rubidium salts, in particular the sodium salts. The inorganic perhydrates
 can be present in the detergent as crystalline solids without further
 protection. However, for certain perhydrates it is advantageous to use
 them as granular compositions which are provided with a coating which
 gives the granular products a better storage stability.
 The preferred perborate is sodium perborate which can be present as the
 monohydrate having the formula NaBO.sub.2 H.sub.2 O.sub.2 or as the
 tetrahydrate having the formula NaBO.sub.2 H.sub.2 O.sub.2.3H.sub.2 O.
 The preferred percarbonate is sodium percarbonate having the formula
 2Na.sub.2 CO.sub.3 3H.sub.2 O.sub.2. The percabonate is preferably used in
 a coated form to increase its stability.
 Organic peracids include all organic peracids customarily used as bleaches,
 including, for example, perbenzoic acid and peroxycarboxylic acids such as
 monoperoxyphthalic or diperoxyphthalic acid, octyldiperoxisuccinic acid,
 diperoxydodecane dicarboxylic acid, diperoxyazelaic acid and an
 imidoperoxycarboxylic acid and also possibly their salts.
 Furthermore, chlorine-containing bleaches such as sodium
 dichloroisocyanurate or sodium trichloroisocyanurate can be present in the
 detergent of the invention.
 The bleach is normally present in the detergent in an amount of from 1 to
 40% by weight, preferably from 2 to 30% by weight and most preferably from
 5 to 20% by weight, of the total weight of the tablet.
 The dishwasher detergent of the invention additionally contains one or more
 bleach activators. These are preferably used in detergents for dishwashing
 processes at temperatures in the range below 60.degree. C. in order to
 achieve sufficient bleaching action. Particularly suitable activators are,
 for example, N- and O-acyl compounds such as acylated amines, acylated
 glycol urils or acylated sugar compounds. Preference is given to
 N,N,N',N'-tetraacetylethylendiamine (TAED), pentaacetylglucose (PAG) and
 tetraacetyl (glycol uril) (TAGU). Other suitable bleach activators are
 catalytically active metal complexes and preferably transition metal
 complexes. Most preferred is TAED.
 Further suitable bleach activators are disclosed in WO 95/01416 the content
 of which is hereby expressly incorporated by reference.
 The bleach activator can be present in the detergent of the invention in an
 amount from 0.1 to 20% by weight and preferably from 1 to 10% by weight of
 the total weight, of the tablet.
 The dishwasher detergent of the invention additionally contains a
 silver/copper corrosion inhibitor. This term encompasses agents which are
 supposed to prevent or reduce the tarnishing of nonferrous metals, in
 particular of silver and copper. Preferred silver/copper corrosion
 inhibitors are benzotriazole or bisbenzotriazoles and also their
 substituted derivatives.
 Further suitable agents are organic and/or inorganic redox-active
 substances and paraffin oil.
 Benzotriazole derivatives are compounds in which the available substitution
 positions of the aromatic ring are partially or completely substituted.
 Suitable substituents are linear or branched C.sub.1-20 -alkyl groups and
 also hydroxy, thio, phenyl or halogen such as flourine, chlorine, bromine
 and iodine. The preferred substituted benzotr-iazole is tolyltriazole.
 Suitable bisbenzotriazoles are those in which the benzotrilazole groups
 are, in each case in the 6 position joined by means of a group X, where X
 can be a bond, a straight-chain alkylene group which may be substituted by
 one or more C.sub.1-4 -alkyl groups and preferably has 1-6 carbon atoms, a
 cycloalkyl radical having at least 5 carbon atoms, a carbonyl group, a
 sulfuryl group, and oxygen or a sulfur atom. The aromatic rings of the
 bisbenzotriazole can be substituted as defined above for benzotriazole.
 Suitable organic redox-active substances are, for example, ascorbic acid,
 indol, methionin, an N-mono (C.sub.1 -C.sub.4 -alkyl)glycine, an
 N,N-Di-(C.sub.1 -C.sub.4 -alkyl)glycine, 2-phenylglycine or a coupler
 and/or developer compound selected from the group consisting of
 diaminopyridines, aminohydroxypyridines, dihydroxypyridines, heterocyclic
 hydrazones, aminohydroxypyrimidines, dihydroxypyrimidines,
 tetraaminopyrimidines, triaminohydroxypyrimidines,
 diaminodihydroxypyrimidines, dihydroxynaphthalines, naphthols,
 pyrazolones, hydroxyquinolines, aminoquinolines, primary aromatic amines
 which in the ortho, meta or para position bear a further free or C.sub.1
 -C.sub.4 -alkyl-substituted or C.sub.2 -C.sub.4 -hydroxyalkyl-substituted
 hydroxy or amino group, and dihydroxybenzines or trihydroxybenzines.
 Suitable inorganic redox-active substances are, for example, metal salts
 and/or metal complexes selected from the group consisting of manganese,
 titanium, zirconium, hafnium, vanadium, cobalt and cerium salts and/or
 complexes where the metals are present in the oxidation states II, III,
 IV, V or VI.
 Particularly suitable are metal salts and/or metal complexes selected from
 the group consisting of MnSO.sub.4, manganese(II) citrate, manganese(II)
 stearate, manganese (II) acetylacetonate, manganese (II)
 1-hydroxyethane-1,1-diphosphonate, V.sub.2 O.sub.5, V.sub.2 O.sub.4,
 VO.sub.2, TiOSO.sub.4, K.sub.2 TiF.sub.6, K.sub.2 ZrF.sub.6, CoSO.sub.4,
 Co(NO.sub.3).sub.2, Ce(NO.sub.3).sub.3.
 Organic and inorganic redox-active substances which are suitable as
 silver/copper corrosion inhibitors are also mentioned in WO 94/26860 and
 WO 94/26859 the content of which is hereby incorporated by reference.
 Suitable paraffin oils are predominantly branched aliphatic hydrocarbons
 having a number of carbon atoms in the range from 20 to 50. The paraffin
 oil is preferably selected from among primarily branched C.sub.25-45
 species having a ratio of cyclic to noncyclic hydrocarbons of from 1:10 to
 2:1, preferably from 1:5 to 1:1.
 The silver/copper corrosion inhibitor is present in the dishwasher
 detergent of the present invention in an amount of preferably from 0.01 to
 5% by weight, particularly preferably from 0.1 to 2% by weight, of the
 total weight of the tablet.
 The dishwasher detergent of the invention can additionally contain other
 customary constituents. These include builders, sequestering agents,
 surface active agents, enzymes, foam inhibitors, fragrances, dyes and
 other auxiliaries.
 Suitable builders are, for example, homopolymeric and copolymeric
 polycarboxylic acids and their partially or fully neutralized salts,
 monomeric polycarboxylic acids and hydroxycarboxylic acids and their
 salts, carbonates, bicarbonates, borates, phosphates, silicates,
 aluminosilicates and also mixtures of such substances.
 As salts of the abovementioned compounds, preference is given to using the
 ammonium and/or alkali metal salts, i.e. the lithium, sodium, potassium
 and rubidium salts, and particularly preferably the sodium salt.
 Suitable polycarboxylic acids are acyclic, alicyclic, heterocyclic and
 aromatic carboxylic acids containing at least two carboxy groups which are
 in each case separated from one another by preferably not more than two
 carbon atoms.
 Polycarboxylates containing two carboxy groups include, for example,
 water-soluble salts of succinic acid, malonic acid,
 (ethylenedioxy)diacetic, acid, maleic acid, diglycolic acid, tartaric
 acid, tartronic acid and fumaric acid. Polycarboxylates containing three
 carboxy groups include, for example, water-soluble citrates.
 Correspondingly, an example of a suitable hydroxycarboxylic acid is citric
 acid.
 Also suitable as a polycarboxylic acid is the homopolymer of acrylic acid.
 As borate builders, it is possible to use borates such as sodium borate and
 also builders comprising borate-forming materials which liberate borates
 under the storage conditions for the cleaning composition or under the
 washing conditions.
 Suitable phosphates are polyphosphates such as tripolyphosphate,
 pyrophosphate, orthophosphate and the polymeric mataphosphate. Examples
 which may be mentioned are alkali metal tripolyphosphates, sodium,
 potassium and ammonium pyrophosphate, sodium and potassium orthophosphate
 and also sodium polymetaphosphate in which the degree of polymerization
 preferably extends from 5 to 21.
 Suitable silicates are sodium silicates such as sodium disilicate, sodium
 metasilicate and crystalline sheet silicates. Also suitable are sodium
 aluminosilicates (zeolites).
 Further suitable builders are disclosed in WO 95/01416, the content of
 which is hereby expressly incorporated by reference.
 The dishwasher detergent of the invention can contain from 40 to 90% by
 weight, preferably from 60 to 80% by weight, of builders, based on the
 total weight of the tablet. Use can here be made of either individual
 builders or mixtures of various abovementioned builders. For example,
 mixtures of carbonates and silicates are suitable.
 Suitable sequestering agents for complexing heavy metal ions which can be
 used according to the invention acre organic phosphonates such as
 amino-alkylene poly(alkylenephosphonate), alkali metal
 ethane-1-hydroxydiphosphonate and nitrilotrimethylenephosphonates.
 Preferred phosphonates are diethylenetriamine penta(methylenephosphonate),
 hexamethylenedi-amine tetra(methylenephosphonate) and hydroxyethylene
 1,1-diphosphonate. Also suitable are aminopolycarboxylates such as
 nitrilotriacetic acid (NTA), methylglycinediacetic acid (MGDA) and also
 polyaspartates.
 According to the invention, the sequestering agent can be present in an
 amount of from 0.01 to 10% by weight, preferably from 0.1 to 2% by weight,
 of the total weight of the tablet.
 Suitable surface-active agents are, for example, nonionic surface-active
 agents. These include, for example, water-soluble ethoxylated C.sub.6-16
 fatty alcohols and C.sub.6-16 mixed ethoxylated/propoxylated fatty
 alcohols and mixtures thereof, and also alkylpolygluclosides.
 A further class of nonionic surface-active agents comprises polyhydroxy
 fatty amides.
 Further suitable surface-active agents are disclosed in WO 95/01416, the
 content of which is hereby expressly incorporated by reference.
 According to the invention, the surface-active agent can be present in an
 amount of from 0.1 to 10% by weight, preferably from 1 to 5% by weight, of
 the total weight of the tablet.
 The dishwasher detergent of the invention can additionally contain one or
 more enzymes customarily used in detergents and selected from, for
 example, proteasers amylases, lipases and esterases.
 The enzymes can be present in the detergent in an amount of from 0.1 to 10%
 by weight, preferably from 1 to 5% by weight, of the total weight of the
 detergent.
 The dishwasher detergent of the invention can additionally contain one or
 more foam inhibitors. Suitable foam inhibitors are all those used in this
 field, for example silicones and paraffin oils.
 The foam inhibitors are preferably present in the dishwasher detergent of
 the invention in an amount of less than 5% by weight of the total weight
 of the detergent.
 Furthermore, the dishwasher detergent of the invention can comprise other
 customary additives such as fragrances, dyes and/or further auxiliaries.
 For example, it is possible to use various polymers such as
 polyvinylpyrrolidone, polyvinylpolypyrrolidone or polyethylene glycol
 (preferably having a molecular weight of 10-10,000) or glycerol as
 auxiliaries which aid the production of the tablets.
 A preferred dishwasher detergent of the invention consists of two layers,
 where the first layer comprises, a) a perborate as bleach, b) sodium
 tripolyphosphate, a disilicate and a carbonate as builders, d) a nonionic
 surface-active agent, d) benzotriazole as silver/copper corrosion
 inhibitor and also, if desired, further auxiliaries and the second layer
 comprises, a) N,N,N',N'-tetraacetylethylenediamine as bleach activator, b)
 sodium tripolyphosphate, a homopolymeric acrylic acid polymer and a
 carbonate as builders, c) a phosphonate as sequestering agent, d) a
 nonionic surface-active agent, e) one or more enzymes and also, if
 desired, further auxiliaries.
 A further preferred dishwasher detergent of the invention consists of two
 layers, where the first layer comprises a) a perborate as bleach, b) a
 citrate, a bicarbonate, and a carbonate as builders, c) a nonionic
 surface-active agent, d) benzotriazole as silver/copper corrosion
 inhibitor and also, if desired, further auxiliaries and the second layer
 comprises a) N,N,N',N'-tetraacetylethylenediamine as bleach activator, b)
 citrate, a bicarbonate, a carbonate, a homopolymeric acrylic acid polymer
 and citric acid as builders, c) a phosphonate as sequestering agent, d) a
 nonionic surface-active agent, e) one or more enzymes and also, if
 desired, further auxiliaries.
 The tablets of the present invention can be produced by any conventional
 method known in the prior art. For example, the constituents of the
 individual layers are separately premixed and then pressed together in
 layers in order to obtain a tablet. The hardness of the tablet and the
 time which this tablet requires to dissolve completely is dependent, inter
 alia, on the pressure used during pressing. The lower the pressure during
 the pressing process, the more crumbly is the tablet obtained and the
 quicker it dissolves in the washing liquor. A higher pressure leads to
 stronger tablets which dissolve correspondingly more slowly. For example,
 pressures of from 0.01 to 70 kN/cm.sup.2 are suitable for the pressing
 process.
 Furthermore, the pressing process can be defined by the force required to
 break the tablets obtained in this way. Such measurements of the hardness
 of the tablet can, for example, be carried out using an Erickson 464H
 hardness testing machine. The tablets of the invention preferably have a
 hardness of 90-130 N.
 The size of the tablets of the invention depends on the desired amount of
 dishwasher detergent which is to be present in the tablet. For example,
 the tablet can weigh 15-25 g. The tablet preferably contains the amount of
 dishwasher detergent which is required for one wash. However, the tablet
 can also consist of larger units which for dosage purposes can, for
 example, be broken at a prescribed fracture position into smaller parts in
 dose form.
 The tablet can have any suitable shape, in particular with a constant
 thickness, for example round or rectangular.

The following examples illustrate the present invention. Percentages are by
 weight.
 Example 1
 Two layer tablets of the following composition (Table 1) were produced on a
 production scale using a high-speed rotation press. The tablets weighed a
 total of 18 g, with 12.6 g being in the first layer and 5.4 g in the
 second layer. A pulverulent composition having the same amounts of
 constituents as the total amount in the two-layer tablet was likewise
 produced (Table 1). The only difference between the two preparations was
 the product form. The tablet was pressed such that the force required to
 break the tablet was approximately 110 N. This measurement was carried out
 using an Erickson 464H hardness testing machine.
 The dissolution rate of the tablets was likewise determined. The
 determination was carried out by measuring the time which the tablets
 required to disintegrate to such a degree that they could pass through 4
 mm openings in a basket immersed in agitated water at 40.degree. C. This
 result is likewise shown in Table 1.
 TABLE 1
 1st 2nd Total
 Constituents Layer % Layer % Tablet % Powder %
 Perborate 16.00 11.20 11.20
 TAED 6.83 2.05 2.05
 STPP 48.00 50.87 48.86 48.86
 Disilicate 5.00 3.50 3.50
 Carbonate 18.64 25.51 20.70 20.70
 Phosphonate 2.72 0.82 0.82
 Polymer 2.72 0.82 0.82
 Nonionic surface-
 active agent 4.50 2.07 3.77 3.77
 Protease 3.37 1.01 1.01
 Amylase 1.33 0.40 0.40
 BTA 0.36 0.25 0.25
 PEG 6.00 4.08 5.42 5.42
 Glycerol 1.50 0.50 1.20 1.20
 Total 100 100 100 100
 Dissolution ca. 10 min 0 min*
 *The powder has a dissolution time of 0 since all particles have a size of
 less than 4 mm.
 TAED = N,N,N',N'-tetraacetylethylenediamine
 STPP = Sodium tripolyphosphate
 BTA = Benzotriazole
 PEG = Polethylene glycol
 Polymer = Homopolymeric acrylic acid polymer
 The action of both the two-layer tablet and the powder of the same
 composition was then determined in accordance with DIN 44990. This method
 describes the testing of dishwasher detergents by means of a visual
 determination of the action on a scale from 1 to 5 (where 5 is assumed to
 be perfectly clean). A dishwasher from Bosch was used with the normal
 65.degree. C. wash program. The water hardness was 18.degree. d. Five
 washes were carried out for each product, with in each case the product
 being automatically metered in by means of the machine's own detergent
 dispensing device.
 The results for milk, which is a significant, enzyme-relevant form of
 soiling are shown in Table 2.
 TABLE 2
 Soiling Two-Layer Tablet Powder
 Milk 3.22 3.08
 Example 2
 Two-layer tablets were produced on a production scale using a high-speed
 rotation press. The tablets weighed 20 g, the first layer contained 14 g
 and the second layer contained 6 g (Table 3). The tablets were pressed
 sufficiently to gain a hardness of 100 N (same hardness testing machine as
 in Example 1). Again, a pulverulent composition having the same
 formulation was also produced (Table 3). The dissolution time of the
 two-layer tablets is shown in Table 3.
 TABLE 3
 1st 2nd Total
 Constituents Layer % Layer % Tablet % Powder %
 Perborate 14.3 10.01 10.01
 TAED 25.00 7.50 7.50
 Citrate 50.01 26.37 42.92 42.92
 Bicarbonate 24.57 17.20 22.36 22.36
 Carbonate 7.21 4.78 6.48 6.48
 Phosphonate 1.66 0.50 0.50
 Polymer 1.66 0.50 0.50
 Citric acid 10.00 3.00 3.00
 Nonionic surface- 3.00 1.00 2.40 2.40
 active agent
 Protease 9.00 2.70 2.70
 Amylase 3.30 0.99 0.99
 BTA 0.36 0.25 0.25
 Glycerol 0.50 0.35 0.35
 Perfume 0.05 0.04 0.04
 Fragrance 0.03 0.01 0.01
 Total 100 100 100 100
 Dissolution ca. 8 min 0 min
 The action of both the two-layer tablet and the power of the same
 composition was then determined in accordance with DIN 44990. A dishwasher
 from Bosch was used with the normal 65.degree. C. wash program. The water
 hardness was 18.degree. d.
 The results for milk, which is a significant, enzyme-relevant form of
 soiling, are shown in Table 4.
 TABLE 4
 Soiling Two-Layer Tablet Powder
 Milk 3.20 2.88
 Comparative Example 3
 In this example, single-layer tablets were produced in accordance with a
 composition already on the market. The tablets were pressed such that the
 strength of the tablets was about 125 N. The dissolution time was likewise
 measured and the results are shown in Table 5. A pulverulent composition
 of the same formulation was likewise produced. The composition is shown in
 Table 5.
 TABLE 5
 Constituents Single-Layer Tablet % Powder %
 Carbonate 16.60 16.60
 Percarbonate 21.90 21.90
 STPP 45.70 45.70
 Disilicate 5.90 5.90
 Phosphonate 2.00 2.00
 PEG 1.00 1.00
 Protease 1.0 1.0
 Amylase 0.4 0.4
 Nonionic 4.25 4.25
 surface-active
 agent
 BTA 0.25 0.25
 Glycerol 1.00 1.00
 Total 100 100
 Dissolution ca. 13 min 0 min
 The action of both the tablet and the powder was again determined in
 accordance with DIN 44990. As before, a dishwasher from Bosch was used.
 Again, the normal 65.degree. C. wash program was used and the water had a
 hardness of 18.degree. d.
 The results for milk, which is a significant enzyme-relevant form of
 soiling, are shown in Table 6.
 TABLE 6
 Single-Layer
 Soiling Tablet Powder
 Milk 3.31 3.88
 It is clear from these examples and comparative examples that a dishwasher
 detergent of the invention which is built up as a simple two-layer tablet
 gives a better washing performance than a comparable powder, although the
 individual constituents of the composition of the invention are completely
 available for washing only after from about 8 to 13 minutes, while in the
 case of a comparable powder all constituents are immediately available.