EP0876465B1 - Dishwasher detergent - Google Patents

Description

The invention is in the field of machine dishwashing detergents and relates to the use of a combination of active ingredients to prevent the Tarnishing of silver or silver-plated wash ware.

When cleaning silverware by machine, in practice always occur again problems in the form of tarnishing and discoloration of the silver surfaces on. Silver can be found here on sulfur-containing substances in the rinse water dissolved or dispersed, react because when cleaning dishes in household dishwashers (HGSM) there are leftovers and with it u. a. also mustard, peas, egg and other sulfur-containing compounds like mercaptoamino acid introduced into the washing liquor. Even during machine washing much higher temperatures and longer contact times favor with the sulfur-containing food residues in comparison tarnishing silver for manual rinsing. Through the intensive cleaning process the silver surface is also complete in the dishwasher degreased and therefore more sensitive to chemical influences.

When using active chlorine-containing cleaners, tarnishing can occur Sulfur-containing compounds are largely prevented because of these compounds by oxidation of the sulfidic functions in a secondary reaction to be converted into sulfones or sulfates. Furthermore lead active chlorine Cleaners due to their usually high pH value of over 12, for electrochemical reasons due to passivation of the silver surface less strong for tarnishing silver.

However, the problem of tarnishing silver has become topical again, as an alternative to the active chlorine compounds active oxygen compounds, such as Sodium perborate or sodium percarbonate were used, which to remove bleachable stains, such as Tea stains / tea deposits, coffee residues, vegetable dyes, lipstick residues and the like serve.

These active oxygen compounds are mainly used in modern lower alkaline machine dishwashing detergents of the new generation of cleaners used with bleach activators. These modern means generally exist from the following function blocks: builder component (complexing agent / dispersant), Alkali carrier, bleaching system (bleach + Bleach activator), enzymes and wetting agents (surfactants).

On the changed recipe parameters of the new generation of active chlorine-free cleaners with lowered pH values and activated oxygen bleaching the silver surfaces are generally more sensitive. In particular due to the low pH, there is a much lower one Passivation of the silver surface. Sit during machine rinsing these agents in the cleaning cycle hydrogen peroxide or active oxygen free. The bleaching effect of the active oxygen-containing cleaners will reinforced by bleach activators, so that even at low temperatures the actually bleaching agent per (vinegar) acid is formed and thus a good bleaching effect is achieved. Under these changed washing conditions not only form sulfidic but also in the presence of silver the oxidizing attack of the intermediately formed peroxides or the active oxygen prefers oxidic deposits on the silver surfaces. Under If the salt load is high, chloride deposits can also form. Reinforced the tarnishing of the silver is also due to higher residual water hardness during the cleaning cycle.

Avoiding silver corrosion, i. H. the formation of sulfidic, The subject of numerous oxidic or chloride deposits on silver is the subject Publications. The corrosion of silver is described in these descriptions especially prevented by so-called silver protection agents.

From the British patent GB 1 131 738 are alkaline dishwashing detergents known as a corrosion inhibitor for silver benzotriazoles contain. In the American patent US 3,549,539 strong alkaline, machine-applicable dishwashing detergent described as an oxidizing agent u. a. Perborate with an organic bleach activator can contain. As anti-tarnish additives and. a. Benzotriazole and iron (III) chloride are also recommended. In doing so pH values of preferably 7-11.5. In the European patent specifications EP 135 226 and EP 135 227 become weakly alkaline, mechanically applicable dishwashing detergent containing peroxy compounds and Activators described as silver protection agents, among others. Benzotriazoles and May contain fatty acids. Finally, is from the German published application DE 41 28 672 discloses that peroxy compounds by addition known organic bleach activators are activated in strong alkaline cleaning agents prevent silver parts from tarnishing.

W094 / 26859, which goes back to the applicant, proposes to prevent silver corrosion, inorganic redox-active substances, in particular salts or complex compounds, certain metals among those Manganese is preferred to add. Draw the funds so produced are characterized by their excellent effect and have proven themselves in practice. Under unfavorable conditions, however, certain color decorations, like them be used on drinking glasses, or plastic objects that are often washed, changed color or deposited become. At least in the case of using manganese sulfate such deposits are colored brown and are therefore consumed by the consumer not accepted.

From European patent application 288 812 it is known that the corrosion of silicate surfaces which have arisen from molten silicates can largely be prevented by using fluorine compounds which are at least slightly soluble in the aqueous medium. Alkali or ammonium fluorides or aluminum hexafluoride or tin tetrafluoride are mentioned, but also fluorosilicates and fluorophosphate. Contrary to common usage, corrosion in the sense of this citation should be understood to mean the buildup of SiO ₂ -containing deposits from silicate-rich detergents on such surfaces.

Surprisingly, it has now been found that such compounds counteract the deposits and decor discoloration if they are with those described in W094 / 26859 redox-active inorganic substances be used together.

• wasserlöslichen, anorganischen redoxaktiven Metallverbindungen und
• anorganischen, wasserlöslichen Fluorverbindungen in Mitteln zum maschinellen Geschirrspülen zur Verhinderung von Silberkorrosion und Dekorverfärbung.

The invention therefore relates to the use of a combination of

• water soluble, inorganic redox active metal compounds and
• inorganic, water-soluble fluorine compounds in machine dishwashing detergents to prevent silver corrosion and discoloration of decor.

The word "corrosion" is in its broadest use in chemistry To interpret meaning, in particular "corrosion" is meant for everyone visually barely noticeable change in a metal surface, here silver stand, be it for example a selective discoloration, be it z. B. a large start-up. Corrosion refers in the sense of this application only on the corrosion of metals, not on the corrosion of surfaces, which are made from molten silicates. Such areas are generally not attacked by lower alkaline agents.

"Inorganic redox-active substances" are such inorganic substances that of an easily occurring reversible oxidation and / or reduction are accessible. For example, the oxides, hydroxides or halides fall ammonium salts or alkali or alkaline earth metals under this definition.

However, the salts or complex compounds of certain are particularly suitable Metals. The use of metal salts and / or metal complexes is preferred selected from the group of transition elements of the periodic table, especially manganese, titanium, zirconium, hafnium, vanadium, Cobalt and cerium salts and / or complexes to prevent silver corrosion, the metals in one of the oxidation states II, III, IV, V or VI are present.

The common definition in chemistry for "oxidation level" is e.g. in "Römpp Chemie Lexikon, Georg Thieme Verlag Stuttgart / New York, 9th edition, 1991, page 3168 "reproduced.

The metal salts or metal complexes used are said to be at least partially be soluble in water. The counterions suitable for salt formation include all usual one, two or three times negatively charged inorganic Anions, e.g. B. oxide, sulfate, nitrate, fluoride, but also organic anions such as B. stearate.

For the purposes of the invention, metal complexes are compounds which consist of a Central atom and one or more ligands exist. The central atom is one of the above Metals in one of the above Oxidation levels. The ligands are neutral molecules or anions that are monodentate or multidentate; the The term "ligand" in the sense of the invention is e.g. in "Römpp Chemie Lexikon, Georg Thieme Verlag Stuttgart / New York, 9th edition, 1990, page 2507 "closer explained. The charge of the central atom is complemented in a metal complex and the charge of the ligand (s) is not on zero, so, ever depending on whether there is a cationic or an anionic excess charge, either one or more of the above Anions or one or more Cations, e.g. B. sodium, potassium, ammonium ions for charge balance. Suitable complexing agents are e.g. Citrate, acetylacetonate or 1-hydroxyethane-1,1-diphosphonate.

Particularly preferred metal salts and / or metal complexes are selected from the group MnSO ₄ , Mn (II) citrate, Mn (II) stearate, Mn (II) acetylacetonate, Mn (II) - [1-hydroxyethane-1,1- diphosphonate], salts of acids of vanadium, based on V ₂ O ₅ , V ₂ O ₄ , VO ₂ (here: called vanadates), TiOSO ₄ , CoSO ₄ , Co (NO ₃ ) ₂ , Ce (NO ₃ ) ₃ and their mixtures. MnSO ₄ is particularly preferred.

These metal salts or metal complexes are generally commercially available substances which can be used for the purpose of the silver corrosion protection according to the invention without prior cleaning. For example, the mixture of pentavalent and tetravalent vanadium (V ₂ O ₅ , VO ₂ , V ₂ O ₄ ) known from SO ₃ production (contact process) is suitable, as is that by diluting a Ti (SO ₄ ) ₂ - Solution resulting titanyl sulfate, TiOSO ₄ .

The inorganic redox-active substances, in particular metal salts or Metal complexes are preferably coated, i.e. completely with one waterproof, but easily soluble at cleaning temperatures coated to prevent their premature decomposition or oxidation during storage to prevent. Preferred coating materials according to known Processes, such as Sandwik melt coating processes from the food industry, are applied, paraffins, micro waxes, waxes are natural Origin such as carnauba wax, candellila wax, beeswax, higher melting Alcohols such as hexadecanol, soaps or fatty acids. The coating material, which is solid at room temperature, is melted State applied to the material to be coated, e.g. by doing finely divided material to be coated in a continuous flow through a also continuously generated spray zone of the melted Coating material is thrown. The melting point must be selected that the coating material during the subsequent use of the Silver corrosion protection agent easily dissolves in the dishwasher or melts quickly. The melting point should therefore be suitable for most applications ideally in the range between 45 ° C and 65 ° C and preferably in Range 50 ° C to 60 ° C.

Inorganic, water-soluble, ionic fluorine compounds from the class of the salts or complex salts which release fluoride ions under the conditions of automatic dishwashing can be used as fluorine compounds. Salts of hydrofluoric acid or hexafluorosilicic acid or mono-, di- or pentafluorophosphoric acid are particularly suitable.
These are in particular the fluorides of the alkali salts such as sodium or potassium, ammonium fluoride, magnesium fluoride and complex fluorides such as magnesium hexafluorosilicate, sodium hexafluorosilicate, potassium hexafluorosilicate, sodium hexafluorosilicate, ammonium hexafluorosilicate. Fluorophosphates of alkali metals or ammonium are also suitable. Preferred among these compounds are the hexafluorosilicate, in particular sodium or magnesium hexafluorosilicate. It is also possible to use aluminum hexafluoride or tin tetrafluoride. However, these substances are not preferred. The fluorine compounds mentioned are used in amounts of 0.1 to 6% by weight, preferably 0.1 to 5 and in particular 0.2 to 2.5% by weight, based on the mixture as a whole.

The inorganic redox-active compounds described above are particularly suitable However, substances to prevent silver corrosion when in lower alkaline Cleaners for machine cleaning of dishes included are. This is all the more surprising than these silver corrosion inhibitors in effect not by the presence of usually in low alkaline cleaners contain oxygen-based bleaches be affected.

Another subject of the invention are therefore low-alkaline agents for machine cleaning of dishes, the 1% by weight solutions of which have a pH of 8 to 11.5, preferably 9 to 10.5, containing 15 to 60% by weight, preferably 30 to 50% by weight of a water-soluble builder component, 5 to 25% by weight, preferably 10 to 15% by weight of an oxygen-based bleach, 1 to 10% by weight, preferably 2 to 6% by weight of an organic , O- or N- (C ₁ -C ₁₂ ) -acyl group-containing bleach activator, 0.1 to 5% by weight, preferably 0.5 to 2.5% by weight of an enzyme, in each case based on the total agent, and Silver corrosion protection agent, an inorganic redox-active substance being contained as the silver corrosion protection agent. Metal salts and / or metal complexes selected from the group consisting of manganese, titanium, zirconium, hafnium, vanadium, cobalt, cerium salts and / or complexes are particularly suitable, the metals being in one of the oxidation states II, III , IV, V or VI are present.

The inorganic redox-active substances are preferred, in particular Metal salts and / or metal complexes in the agents according to the invention in a total amount of 0.05 to 6% by weight, preferably 0.2 to 2.5% by weight, based on the total mean.

Organic, O- or N- (C ₁ -C ₁₂ -) acyl group-containing bleach activators are substances in which at least one C ₁ -C ₁₂ acyl group, preferably the acetyl group, is attached to a 0 or an N atom contained in the substance is bound, and the perhydrolysis thereof provides C ₁ -C ₁₂ -alkanic acids, preferably peracetic acid.

In principle, all builders commonly used in machine dishwashing detergents are suitable as water-soluble builder components, eg. B. polymeric alkali metal phosphates, which may be in the form of their alkaline neutral or acidic sodium or potassium salts. Examples include: tetrasodium diphosphate, disodium dihydrogen diphosphate, pentasodium triphosphate, so-called sodium hexametaphosphate and the corresponding potassium salts or mixtures of sodium hexametaphosphate and the corresponding potassium salts or mixtures of sodium and potassium salts. The amounts of phosphate are in the range of up to about 30% by weight, based on the total agent; however, the agents according to the invention are preferably free of such phosphates. Other possible water-soluble builder components are e.g. B. organic polymers of native or synthetic origin, especially polycarboxylates, which act in particular in hard water systems as a co-builder. For example, polyacrylic acids and copolymers of maleic anhydride and acrylic acid and the sodium salts of these polymer acids are suitable. Commercial products include Sokalan ^(R) CP 5 and PA 30 from BASF, Alcosperse ^(R) 175 or 177 from Alco, LMW ^(R) 45 N and SP02 N from Norsohaas. The native polymers include, for example, oxidized starch (e.g. German patent application P 42 28 786.3) and polyamino acids such as polyglutamic acid or polyaspartic acid and NTA and their derivatives.

Other possible builder components are naturally occurring hydroxycarboxylic acids such as B. mono-, dihydroxysuccinic acid, α-hydroxypropionic acid and gluconic acid. Preferred builder components are the salts of Citric acid, especially sodium citrate. As sodium citrate come anhydrous Trisodium citrate or preferably trisodium citrate dihydrate in Consideration. Trisodium citrate dihydrate can be fine or coarse crystalline Powder can be used. Depending on the ultimately in the pH set according to the invention can also be citric acid available.

Sodium perborate mono- and tetrahydrate or sodium percarbonate are primarily considered as oxygen-based bleaches. The oxygen-based bleach is therefore preferably a percarbonate salt, especially sodium percarbonate. Since active oxygen only develops its full effect on its own at elevated temperatures, so-called bleach activators are used to activate it in the dishwasher. Organic bleach activators containing 0- or N- (C ₁ -C ₁₂ ) acyl groups, such as PAG (pentaacetyl glucose), DADHT (1,5-diacetyl-2,4-dioxo-hexahydro-1,3,5-triazine) are used as bleach activators ) and ISA (isatoic anhydride), but preferably N, N, N ', N'-tetraacetylethylene diamine (TAED). In addition, the addition of small amounts of known bleach stabilizers such as, for example, phosphonates, borates or metaborates and metasilicates and magnesium salts such as magnesium sulfate may also be useful.

To better detach protein, fat or starch-containing food residues, the dishwashing detergents according to the invention contain enzymes such as proteases, amylases, lipases and cellulases, for example proteases such as BLAP ^(R) 140 from Henkel; Optimase ^(R) -M-440, Optimase ^(R) -M-330, Opticlean ^(R) -M-375, Opticlean ^(R) -M-250 from Solvay Enzymes; Maxacal ^(R)
CX 450,000, Maxapem ^(R) from Gist Brocades; Savinase ^(R) 4.0 T, 6.0 T, 8.0 T from Novo; Esperase ^(R) T from Ibis and amylases such as Termamyl ^(R) 60 T, 90 T from Novo; Amylase-LT ^(R) from Solvay Enzymes or Maxamyl ^(R) P 5000, CXT 5000 or CXT 2900 from Gist Brocades; Lipases such as Lipolase ^(R) 30 T from Novo; Cellulases such as Celluzym ^(R) 0.7 T from Novo Nordisk. The dishwashing detergents preferably contain proteases and / or amylases.

If desired, the agents according to the invention additionally contain the alkali carriers contained in conventional low-alkaline machine dishwashing detergents, such as, for. B. alkali silicates, alkali carbonates and / or alkali hydrogen carbonates. The alkali carriers commonly used include carbonates, hydrogen carbonates and alkali silicates with a SiO ₂ / M ₂ O (M = alkali atom) molar ratio of 1.5: 1 to 2.5: 1. Alkali silicates can be used in amounts of up to 30% by weight. %, based on the total, may be included. The use of the highly alkaline metasilicates as alkali carriers is preferably avoided. The alkali carrier system preferably used in the agents according to the invention is a mixture of essentially carbonate and hydrogen carbonate, preferably sodium carbonate and hydrogen carbonate, in an amount of up to 60% by weight, preferably 10 to 40% by weight, based on the total agent , is included. Depending on which pH value is ultimately desired or set, the ratio of carbonate and bicarbonate used varies; Usually, however, an excess of sodium hydrogen carbonate is used, so that the weight ratio between hydrogen carbonate and carbonate is generally 1: 1 to 15: 1.

If appropriate, surfactants, in particular low-foaming nonionic surfactants, can also be added to the agents according to the invention, which serve to better detach fatty food residues, as wetting agents, as granulating aids or as dispersing aids for better, homogeneous distribution of the aforementioned silver corrosion inhibitors in the washing liquor and on the silver surfaces. Their amount is then up to 5% by weight, preferably up to 2% by weight. Extremely low-foam connections are usually used. These preferably include C ₁₂ -C ₁₈ alkyl polyethylene glycol polypropylene glycol ethers, each containing up to 8 moles of ethylene oxide and propylene oxide units in the molecule. But you can also use other, known as low-foam nonionic surfactants, such as. B. C ₁₂ -C ₁₈ alkyl polyethylene glycol polybutylene glycol ether, each with up to 8 moles of ethylene oxide and butylene oxide units in the molecule, end-capped alkyl polyalkylene glycol mixed ethers and the foaming but ecologically attractive C ₈ -C ₁₄ alkyl polyglucosides with a degree of polymerization of about 1 - 4 ( e.g. APG ^(R) 225 and APG ^(R) 600 from Henkel) and / or C ₁₂ -C ₁₄ alkyl polyethylene glycols with 3 - 8 ethylene oxide units in the molecule. Bleached quality should be used, otherwise brown granules will result. Also suitable are surfactants from the family of glucamides, such as, for example, alkyl-N-methyl-glucamides (alkyl = fatty alcohol with the C chain length C ₆ -C ₁₄ ). It is partially advantageous if the surfactants described are used as mixtures, for. B. the combination of alkyl polyglycoside with fatty alcohol ethoxylates or glucamides with alkyl polyglycosides etc.

If the cleaning agents foam too much during use, them up to 6% by weight, preferably about 0.5 to 4% by weight of one foam-suppressing compound, preferably from the group of silicone oils, Mixtures of silicone oil and hydrophobicized silica, paraffin oil / Guerbet alcohols, Paraffins, hydrophobized silica, the bisstearic acid amides and other other well known commercially available defoamers be added. Other optional additives are e.g. B. Perfume oils.

The dishwashing detergents according to the invention are preferably in powder form, granular or tablet-like preparations that are in themselves customary, for example by mixing, granulating, roller compacting and / or can be produced by spray drying.

For the preparation of cleaning agents according to the invention in tablet form, the procedure is preferably such that all constituents are mixed with one another in a mixer and the mixture by means of conventional tablet presses, for example eccentric presses or rotary presses, with compression pressures in the range from 200 · 10 ⁵ Pa to 1 500 · 10 ⁵ Pa pressed. In this way, unbreakable tablets are obtained with a flexural strength of normally more than 150 N that are sufficiently quickly soluble under conditions of use. A tablet produced in this way preferably has a weight of 15 g to 40 g, in particular 20 g to 30 g, with a diameter of 35 mm to 40 mm.

The production of machine dishwashing detergents in the form of non-dusting, storage-stable free-flowing powders and / or granules with high Bulk densities in the range from 750 to 1000 g / l are characterized by that in a first stage of the process with the builder components at least a proportion of liquid mixture components while increasing the Bulk density of this premix is mixed and subsequently - if desired after intermediate drying - the other components of the dishwasher detergent, including the inorganic redox-active substances combined with the premix obtained in this way.

As a possible alkali carbonate content the alkalinity of the product strongly influenced, the intermediate drying must be carried out so that the Disintegration of sodium bicarbonate to sodium carbonate as low as possible (or at least as constant as possible). An additional through drying The resulting sodium carbonate portion should namely in the formulation of Granulate recipe are taken into account. Low drying temperatures not only counteract sodium bicarbonate decay, but also also increase the solubility of the granulated detergent in the Application. It is therefore advantageous when drying a supply air temperature that on the one hand as low as possible to avoid bicarbonate decay should be and which, on the other hand, must be as high as necessary to produce a product with good storage properties. Drying is preferred an inlet air temperature of approx. 80 ° C. The granules themselves shouldn't be on Temperatures above about 60 ° C are heated. In the first part of the The builder is usually mixed with at least a mixing process another component of the dishwashing detergent with the liquid components acted upon. For example, a preliminary stage can be considered, in which the builder component in admixture with perborate with the liquid non-ionic surfactants and / or the solution of the fragrances and is intimately mixed. Below are the remaining components added and worked through the entire mixture in the mixing device and homogenized. The use of additional amounts of liquid, in particular the use of additional water is here in the Usually not required. The resulting mixture of substances then lies as free-flowing, dust-free powder of the desired high bulk density about in the range of 750 to 1000 g / l.

The pre-granules are then mixed with the missing components of the dishwashing detergent, including inorganic redox-active substances, to the finished product mixed. The mixing time is all shown here Cases both in the preliminary stage of the compacting mixture under influence of liquid components as in the final mix below with the other components in the range of a few minutes, for example in the range from 1 to 5 minutes.

In a particular embodiment, it can be used in the manufacture of fine Granules may be useful by powdering the surface of the formed Granules a further stabilization and leveling adjust. Small amounts of water glass powder are particularly suitable for this or powdered alkali carbonate.

The funds to be used can be found both in household dishwashers as used in commercial dishwashers. The addition takes place by hand or using suitable dosing devices. The application concentrations in the cleaning liquor are preferably about 2 to 8 g / l 3 to 6 g / l.

The washing program of a household dishwasher is generally through some intermediate rinse cycles following the cleaning cycle with clear Water and a rinse aid supplemented with a common rinse aid and ended. After drying, you not only get a completely clean one and in terms of hygiene, perfect dishes, but in front especially bright silver cutlery.

example A) Preparation of the cleaner

A low-alkaline cleaner for household dishwashers was produced, whose 1% by weight solution in distilled water has a pH of 9.5. They were used for this 56.0% by weight Trisodium citrate dihydrate 36.1% by weight Sodium bicarbonate 6.1% by weight Sodium carbonate, anhydrous 1.8% by weight Mixture of nonionic surfactants from C ₈ to C ₁₀ alkyl oligoglucoside and C ₁₂ to C ₁₄ fatty alcohol 2EO ethoxylate in a ratio of 1: 1.

The base product obtained in this way was disassembled into a dishwashing detergent as follows: 81% by weight Basic product 12% by weight Sodium percarbonate 4% by weight Bleach activator TAED 2% by weight Manganese sulfate monohydrate coated with paraffin (1.5% by weight of manganese salt, based on the recipe) rest Enzymes, especially protease and amylase.

The product thus obtained was at a dosage of 30 g per Washing program, washing attempts in a Bosch SMS 7082 machine 65 ° C (universal program). The machine was filled with water from fed about 16 ° dH.

Decorative glasses were used as wash ware, which contain high-bleach melting colors on the one hand or with lead-free colors based on bismuth were printed on the other side. The print showed red, blue, yellow, green and white swatches.

After 25 rinsing cycles, there were already strong brown discolourations in the white field.

The rinsing experiments were repeated with a second agent, the 3 wt .-% Magnesium hexafluorosilicate were mixed. After 25 rinse cycles showed even white fields with minimal discoloration.

Claims (13)

1. The use of a combination of

   water-soluble, inorganic redox-active metal compounds and

   inorganic, water-soluble fluorine compounds in dishwasher detergents for preventing the corrosion of silver and the discoloration of decoration.
2. The use claimed in claim 1, characterized in that the metal salts and/or metal complexes are selected from the group consisting of MnSO₄, Mn(II) citrate, Mn(II) stearate, Mn(II) acetyl acetonate, Mn(II)-[1-hydroxyethane-1,1-diphosphonate].
3. The use claimed in claims 1 and 2, characterized in that the inorganic water-soluble ionic fluorine compounds used are salts or complex salts which eliminate fluoride ions under machine dishwashing conditions, more particularly alkali metal or ammonium salts of hydrofluoric acid, hexafluorosilicic acid, mono-, di- or pentafluorophosphoric acid.
4. The use claimed in claims 1 to 3, characterized in that the inorganic water-soluble ionic fluorine compounds are used in quantities of 0.1 to 6% by weight.
5. The use claimed in claims 1 to 4, characterized in that manganese sulfate is used as the water-soluble, inorganic redox-active compound.
6. A low-alkali dishwasher detergent of which a 1% by weight solution has a pH value of 8 to 11.5 and preferably 9 to 10.5 and which contains 15 to 60% by weight and preferably 30 to 50% by weight of a water-soluble builder component, 5 to 25% by weight and preferably 10 to 15% by weight of an oxygen-based bleaching agent, 1 to 10% by weight and preferably 2 to 6% by weight of an organic bleach activator containing O- or N-(C_1-12)-acyl groups, 0.1 to 5% by weight and preferably 0.5 to 2.5% by weight of an enzyme, based on the detergent as a whole, and silver corrosion inhibitor, characterized in that an inorganic, water-soluble redox-active metal compound is used as the silver corrosion inhibitor while an inorganic, water-soluble ionic fluorine compound is used to prevent the discoloration of decoration.
7. A detergent as claimed in claim 6, characterized in that the metal salt is MnSO₄.
8. A detergent as claimed in claims 6 and 7, characterized in that salts of hydrofluoric acid, hexafluorosilicic acid or fluorophosphoric acids with the alkali metals, ammonium or magnesium are used as the fluorine compounds.
9. A detergent as claimed in claims 6 to 8, characterized in that the inorganic redox-active substances are used in a quantity of 0.05 to 6% by weight and preferably 0.2 to 2.5% by weight, based on the detergent as a whole, and the inorganic, water-soluble ionic fluorine compounds are used in quantities of 0.1 to 5% by weight and preferably in quantities of 0.2 to 2.5% by weight.
10. A detergent as claimed in claims 6 to 9, characterized in that the water-soluble builder component is a salt of citric acid, preferably trisodium citrate and/or its dihydrate.
11. A detergent as claimed in claims 6 to 10, characterized in that the oxygen-based bleaching agent is a percarbonate salt, preferably sodium percarbonate.
12. A detergent as claimed in claims 6 to 11, characterized in that the organic bleach activator containing O- or N-(C_1-12)-acyl groups is N,N,N',N'-tetraacetyl ethylenediamine (TAED).
13. A detergent as claimed in claims 6 to 12, characterized in that amylases, proteases and/or lipases in particular are used as enzymes.