Dishwashing composition for cleaning dishes, method for washing dishes and dishwasher

Abstract

The invention relates to a dishwashing composition for cleaning dishes, containing between 22 wt.% and 60 wt.% of an aminotricarboxylic acid and / or a salt thereof, wherein the aminotricarboxylic acid has the general formula (I) in which - R1, R2 and R3 independently are unsubstituted alkyl groups or substituted alkyl groups with chain lengths from C1 to C4; - n is 0 or 1; and - X is an organic substituent, in particular methyl, ethyl or a combination thereof. The invention further relates to a method for washing dishes and a dishwasher for using the dishwashing composition or for carrying out the method.

Description

[0001] The invention relates to a dishwashing composition for cleaning dishes, a method for washing dishes, and a dishwasher for using the dishwashing composition and the method for washing dishes.

[0002] Dishwashing programs in dishwashers, especially household dishwashers, involve a combination of thermodynamic and hydraulic processes, including the addition of detergent to a wash liquid or water. Generally, dishwashing in standard dishwashers can be divided into three steps: cleaning, rinsing, and drying. Detergent is typically added to the wash liquid during the first few minutes of the cycle to initiate the cleaning process as the liquid heats up and its temperature begins to rise. Depending on the program, rinse aid is also added towards the end of the cycle, once the majority of the soiling has been removed from the dishes. A drying cycle completes the dishwashing process.

[0003] Both tablet and powder dishwashing detergents contain a chemical bleaching system based on hydrogen peroxide (sodium percarbonate), TAED (tetraacetylethylenediamine), and a manganese catalyst. Because powdered detergents are highly hygroscopic, ambient humidity can cause the percarbonate to prematurely release hydrogen peroxide, which then reacts with the other ingredients and oxidizes them prematurely. Under these conditions, powdered detergents can agglomerate during storage and lose their bleaching effect.

[0004] Liquid detergents offer the advantage of simpler and more precise dosing for both users and automatic dosing systems. They are also less susceptible to storage problems, as they inherently have a high water content and, unlike tablets and powders, are insensitive to the effects of additional moisture.

[0005] Liquid detergents, however, have the disadvantage of lacking a chemical bleaching system like those found in tablets and powders, since the chemical agents in the bleaching system are sensitive to moisture, as mentioned earlier. As an alternative, liquid detergents therefore contain a chemical complexing agent. This complexing agent, which makes up about 2 to 5 percent of the total weight of the liquid detergent, has the ability to form stable complexes with polyvalent ions, and in particular with the water-hardening agents Ca 2+ and Mg 2+as well as with transition and heavy metal ions such as Fe 3+ , Mn 2+ , Cu 2+ etc. to form.

[0006] Stains, especially from tea, are caused by hard water cations (Ca 2+ and Mg 2+ ) or are firmly "glued" to the hydrophilic surfaces of cups and dishes by the aforementioned transition and heavy metal ions. It is known that complexing agents can improve the removal of these stubborn stains to a small extent, even without bleach. For this reason, complexing agents are an ingredient in almost all commercially available liquid dishwashing detergents. However, the effectiveness in removing such stubborn and firmly adhering stains is still not satisfactory.

[0007] The object of the present invention is to provide a dishwashing composition for cleaning dishes which has a better cleaning effect on tea stains and similar stubborn soiling. A further object of the present invention is to provide a method for washing dishes with a correspondingly better cleaning effect, as well as a dishwasher for using the improved dishwashing composition and / or for carrying out the improved method.

[0008] The problems are solved according to the invention by a dishwashing composition with the features of claim 1, by a method according to claim 7 for washing dishes, and by a dishwasher according to claim 14. Advantageous embodiments with expedient further developments of the invention are specified in the respective dependent claims, wherein advantageous embodiments of each aspect of the invention are to be regarded as advantageous embodiments of the other aspects of the invention.

[0009] A first aspect of the invention relates to a dishwashing composition for cleaning dishes, particularly in a dishwasher. An improved cleaning effect, especially of tea stains and other firmly adhering soils, is made possible according to the invention by the fact that the dishwashing composition contains between 22 wt.% and 60 wt.% of an aminotricarboxylic acid and / or a salt thereof, wherein the aminotricarboxylic acid has the general formula (I) in which - R1, R2 and R3 independently of each other is an unsubstituted alkyl group or a substituted alkyl group with chain length C1 to C4, that is in particular methylene, ethyl, propyl, i-propyl, butyl, i-butyl and / or tert-butyl; - n is 0 or 1; and - X is an organic substituent, in particular methyl, ethyl or a combination thereof.

[0010] In other words, according to the invention, the dishwashing composition has a significantly higher concentration of the aminotricarboxylic acid with formula (I) or a salt thereof of 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59% or 60% compared to usual concentrations of complexing agents, which are around 2% to 5%. Within the scope of this disclosure, percentages are generally to be understood as percentages by weight, unless otherwise stated or evident from the context. The stated weight fraction of the aminotricarboxylic acid always refers to the sum of all compounds and any salts of these compounds falling under formula (I), based on the total weight of the dishwashing composition.The invention is based on the finding that increasing the concentration of complexing agents from a maximum of 5% to at least 22% or preferably more has a surprisingly strong effect on the removal of tea stains and similar pigmented soils (e.g., those containing carotenes and the like) and can contribute to the complete or at least substantially complete removal of these soils from dishes during a standard dishwasher cycle. Below approximately 22%, on the other hand, practically no experimentally demonstrable improvement in cleaning performance according to DIN EN 60436 can be observed. The compounds of general formula (I) are readily soluble in water, form particularly stable complexes with cations having a charge of at least +2 even at relatively low temperatures, and also exhibit good environmental compatibility due to their readily biodegradable nature.

[0011] In an advantageous embodiment of the invention, the aminotricarboxylic acid of general formula (I) is methylglycine diacetic acid (MGDA) and / or a sodium and / or potassium salt thereof. In other words, the aminotricarboxylic acid has the chemical formula or is a salt thereof, for example a trisodium salt:

[0012] Thus, in the general formula (I) R1 = R2 = CH2, n=0 and X=CH3 (R3 is irrelevant because n=0). It is understood that other salts are also conceivable, for example a tripotassium salt or a mixed sodium-potassium salt. The aforementioned aminotricarboxylic acid (methylglycine diacetic acid, MGDA) forms particularly stable 1:1 chelate complexes with cations having a charge of at least +2, especially with Ca 2+ , Mg 2+ , Fe 3+ etc. and thus contributes particularly efficiently to the removal of tea stains or similar soiling.

[0013] In a further advantageous embodiment of the invention, the proportion of the aminotricarboxylic acid of general formula (I) and / or its salt in the total mass of the dishwashing composition is between 25 wt.% and 50 wt.%. From a wt. percentage of 25 wt.%, experimental tests according to DIN EN 60436 show a significant improvement in the cleaning effect with regard to tea stains, regularly increasing from approximately 0 to 1.35 or more. The overall cleaning effect of the dishwashing composition also increases by up to 10% or more. This improvement in cleaning effect increases slightly above 25 wt.% and reaches its maximum at approximately 50 wt.%. Between 50 wt.% and 60 wt.%, there is no or only a slight improvement in cleaning effect. Determining an optimal concentration between 25 wt.% and 50 wt.% is therefore not possible.The percentage used in the production of the dishwashing detergent composition therefore depends essentially on cost-benefit considerations.

[0014] Further advantages arise from the fact that the dishwashing detergent composition additionally comprises at least one auxiliary substance, wherein the auxiliary substance is selected from a group that includes water, binders, surfactants, in particular non-ionic surfactants, thickeners, chelating agents, superabsorbents, glass protectants, pH buffers, scale inhibitors, oxygen bleach, bleach activators, sequestering agents, corrosion inhibitors, antifoaming agents, protease enzymes, amylase enzymes, lipase enzymes, preservatives, dyes, fragrances, and any mixtures thereof. This allows for optimal tailoring of the dishwashing detergent composition to a desired application. The following compounds are preferred – individually and in any combination – as ingredients for the individual substance classes: propylene glycol as a binder, xanthan gum as a thickener, etc.Viscosity regulator, itaconic acid as chelating agent and binder, sorbitol as binder, sodium polyacrylate as binder, zinc acetate as glass protection sequestrant, citric acid buffer as pH buffer and phenoxyethanol as preservative.

[0015] According to a further advantageous embodiment, the dishwashing composition for particularly high cleaning power comprises, by weight percentage, between 30% and 60%, in particular between 34% and 53%, water; between 22% and 60%, in particular between 25% and 50%, the aminotricarboxylic acid according to formula (I) and / or a salt thereof; between 3% and 7%, in particular between 4% and 6%, a binder; between 1.5% and 2.5%, in particular between 1.6% and 2.4%, a surfactant; between 0.07% and 0.15%, in particular between 0.08% and 0.12%, a thickener; between 0.07% and 1.5%, in particular between 0.8% and 1.2%, a chelating agent; between 1.5% and 2.5%, in particular between 1.6% and 2.4%, a binder; and between 3% and 7%, in particular between 4% and 6%. Superabsorbent, between 0.07% and 0.15%, in particular between 0.08% and 0.12%; glass protectant, between 0.07% and 0.15%, in particular between 0.08% and 0.12%; pH buffer, between 2.7% and 4.5%.in particular between 2.8% and 4.2% protease enzymes, between 0.3% and 0.7%, in particular between 0.4% and 0.6% amylase enzymes, between 0.3% and 0.7%, in particular between 0.4% and 0.6% preservatives, and optionally at least one colorant and / or at least one fragrance. The optional proportion of the at least one colorant and / or the at least one fragrance can generally be chosen relatively freely according to the desired coloring or flavoring. In general, suitable weight proportions of the colorant(s) are between 0.001% and 0.004%, in particular between 0.002% and 0.003%, and / or of the fragrance(s) between 0.0001% and 0.004%, in particular between 0.005% and 0.000%.0.01%. In some cases, however, only a few drops of colorant and / or fragrance are sufficient per kilogram of dishwashing detergent. This depends heavily on the desired color or aroma profile of the detergent. The dishwasher detergent is highly stable against both oxidation during storage and thermal stress during storage in automatic dosing dishwashers.

[0016] In a further advantageous embodiment of the invention, the dishwashing composition is formulated in powder form, in tablet form or in liquid form, with the liquid form being preferred due to its easier dosing, particularly by dosing systems of dishwashers.

[0017] A second aspect of the invention relates to a method for washing dishes, comprising washing the dishes with a washing liquid that includes a dishwashing composition according to the first aspect of the invention. This allows for particularly efficient and reliable removal of tea stains and similar soiling. Further features and their advantages resulting from this are described in the first aspect of the invention. Apart from the ingredients of the dishwashing composition, the washing liquid initially preferably consists at least predominantly or exclusively of water, in particular tap water. The method according to the invention can, for example, be implemented as a dishwashing program in a dishwasher.

[0018] In an advantageous embodiment of the invention, the dishwashing composition is added discontinuously to the washing liquid in two or more batches. Surprisingly, the aminotricarboxylic acid of general formula (I), which acts as a complexing agent, significantly improves its chemical activity in this way compared to a single addition of the entire quantity. Without being bound to this theory, it is assumed that the improvement in cleaning performance through batch addition is partly due to the change in pH. Furthermore, it is assumed that some of the aminotricarboxylic acid is initially consumed by complexing metal ions present in the washing liquid. The second and each subsequent added batch can therefore act exclusively or at least predominantly on tea stains and similar soiling on the dish surfaces.Furthermore, different batches can be added at different temperatures to optimally adjust the complexation selectivity for specific ions to the degree of soiling on the dishes and the composition of the washing liquid. Generally, at higher washing liquid temperatures than room temperature (20°C), those ions that fix tea stains and similar soiling to the substrates, i.e., the dish surfaces, are complexed more selectively.

[0019] In a further advantageous embodiment of the invention, a first batch of the dishwashing composition is added to the wash liquid in a weight fraction of between 10 wt.% and 30 wt.%, in particular about 20 wt.%, of the total weight of the dishwashing composition to be added. In other words, initially only a minor weight fraction of about 10% to 30% of the dishwashing composition is added to the wash liquid in order to complex any cations already present therein. Normally, about 20 wt.%, based on the total mass of the dishwashing composition to be added, has proven to be particularly advantageous. Alternatively or additionally, a second batch of the dishwashing composition is added to the wash liquid in a weight fraction of between 90 wt.% and 70 wt.%, in particular about 80 wt.%, of the total weight of the dishwashing composition to be added.In other words, after the first batch is added, the entire remaining portion of the dishwashing liquid is preferably added as a second and final batch to achieve the best possible cleaning effect on tea stains, etc. In a further embodiment of the invention, it has proven advantageous to add successive batches of the dishwashing liquid to the wash liquid at intervals of at least 5 minutes, particularly between approximately 15 and 20 minutes. This generally achieves an optimum between cleaning efficiency and cleaning time.

[0020] In a further advantageous embodiment of the invention, the dishwashing composition is added, at least partially, to the wash liquid for the first time when the wash liquid has been heated to a temperature of at least 35 °C, and preferably at least 40 °C. In other words, the dishwashing composition is not added to the cold or unheated wash liquid as is customary – possibly after a pre-rinse program – but only for the first time – either as a single addition or as the first of two or more batches – when the wash liquid has already been heated to the minimum temperature of at least 35 °C, and preferably 40 °C or higher.Surprisingly, it was discovered that the addition of the dishwashing composition at elevated temperature, in conjunction with the inventive formulation, results in a synergistic effect on the cleaning action, particularly of tea stains, which goes beyond the mere combination of the isolated individual effects. Without being bound to this theory, it is assumed that the combination of elevated temperature and an unusually high concentration of aminotricarboxylic acid of formula (I) leads to a particularly rapid, specific, and stable complexation of those cations responsible for the strong adhesion of tea stains and other contaminants to the dish surface. Alternatively or additionally, it is provided that at least a portion of the dishwashing composition is added to the wash liquid no later than when the wash liquid has been heated to a temperature between approximately 48 °C and approximately 55 °C.In other words, it is intended that the dishwashing composition, or in the case of batch-wise addition, a residual batch, is added to the washing liquid at the latest when the latter has been heated to at least approximately 48 °C, preferably to approximately 50 °C, and at most to approximately 55 °C. Although addition above 55 °C is of course possible, it has been shown that the synergistic effect of the dishwashing composition formulation according to the invention and its addition at elevated washing liquid temperatures is limited to a temperature range extending up to approximately 55 °C. Higher temperatures, on the other hand, no longer lead to a significant improvement in cleaning performance.

[0021] In a further advantageous embodiment of the invention, the inventive method is carried out using a dishwasher in a washing chamber of the dishwasher. This allows for particularly convenient, efficient and reliable dishwashing.

[0022] Further advantages arise when the dishwashing detergent is added to the wash liquid no earlier than after the completion of a pre-rinse cycle and / or before a rinse cycle. This ensures particularly high cleaning efficiency, as the detergent can develop its maximum cleaning effect during the main wash cycle. In contrast, pre-rinse cycles are generally too short and use only cold wash liquid, as they serve only to remove loose soils. Rinse cycles, on the other hand, include the addition of rinse aid, which can potentially reduce the effectiveness of the dishwashing detergent, and typically take place towards the end of the entire wash cycle.

[0023] In a further advantageous embodiment of the invention, it is provided that the dishwashing composition is added to the washing liquid by means of a dosing system of the dishwasher, wherein the dosing system adds the dishwashing composition depending on at least one parameter determined by a control device of the dishwasher from the group consisting of temperature of the washing liquid, volume of the washing liquid, total quantity of the dishwashing composition, current process status of a washing program to be carried out, degree of soiling of the dishes, hardness of the washing liquid, batch number of the dishwashing composition, batch proportion of the total quantity of the dishwashing composition and addition rate of the dishwashing composition.In other words, the dishwasher has a control unit that determines one or more of the aforementioned parameters and, depending on the determined parameter(s), controls the dishwasher's dosing system accordingly to add the desired amount of dishwashing detergent to the wash liquid at the desired time. This ensures optimal cleaning performance even under varying cleaning conditions. The control unit can access sensor values, characteristic curves, user input, or local or remote storage (cloud) to determine the parameter(s). The control unit can be located inside the dishwasher housing or externally and can be connected, for example, via a wireless or wired network.

[0024] A third aspect of the invention relates to a dishwasher, in particular a household dishwasher, for washing dishes, comprising a wash chamber in which the dishes can be exposed to a washing liquid, a dosing chamber for a dishwashing composition according to the first aspect of the invention, a dosing system configured to add the dishwashing composition to the washing liquid, and a control device configured to control and / or regulate the dishwasher so that it carries out a method according to the second aspect of the invention. This enables particularly efficient and thorough cleaning, especially of dishes with tea stains and similar soiling. Further features and their advantages resulting from this can be found in the descriptions of the first and second aspects of the invention.Furthermore, additional features of the invention can be derived from the claims, the figures and the figure description.

[0025] The features and combinations of features mentioned in the description, as well as those shown in the figure description and the figures themselves, are not only usable in the combinations specified, but also in other combinations without departing from the scope of the invention. Thus, embodiments of the invention that are not explicitly shown and explained in the figures, but which can be derived from the explained embodiments through separate combinations of features or generated by such combinations, are also to be considered disclosed. Embodiments and combinations of features that do not exhibit all the features of an originally formulated independent claim are also to be considered disclosed. Furthermore, embodiments and combinations of features that go beyond or deviate from the combinations of features set forth in the cross-references of the claims are also to be considered disclosed. This shows: Fig. 1 a diagram of the performance points of three dishwashing compositions depending on an MGDA concentration; Fig. 2 a diagram of a first dishwashing program not according to the invention, in which a dishwashing composition according to the invention is used; Fig. 3 a diagram of a second dishwashing program according to the invention; Fig. 4 a diagram of a third dishwashing program according to the invention; Fig. 5. A diagram of the performance values ​​of the three dishwasher programs in terms of tea stain removal; and Fig. 6 a diagram of the performance values ​​of the dishwashing composition according to the invention in comparison to commercially available liquid dishwashing detergents.

[0026] Fig.Figure 1 shows a diagram of the performance points (P) of three dishwashing detergent formulations containing 5%, 20%, and 30% w / w of methylglycine diacetic acid (MGDA) or its salts. The performance points achieved range from 0 to 5 points and were measured according to the DIN EN 60436 standard. The right-hand bars indicate the overall performance of each dishwashing detergent formulation, while the left-hand bars indicate the specific performance for tea stain removal. With the exception of the different MGDA content, the three dishwashing detergent formulations have the same ingredients (see Table 1). An MGDA content of 5% w / w corresponds to the maximum levels typically found in dishwashing detergents. It can be seen that even an increase in the MGDA content from 5% w / w to 20% w / w...Initially, the -% only resulted in a slight improvement in overall performance (3.81 points -> 4.04 points) and no effect on the removal of tea stains (0 points -> 0 points). However, above 20 wt% MGDA content, not only does the overall performance continue to increase, but with an exemplary 30 wt% MGDA in the dishwashing composition according to the invention, a surprising 1.35 performance points are achieved for the removal of tea stains (with 4.26 points overall performance). The in . Fig. The demonstrated improvement in the removal of tea stains through an unusually high MGDA concentration in the dishwashing liquid represents only one advantageous aspect of the invention. A synergistic effect also results from the dosing temperature at which the dishwashing liquid according to the invention is (first) added to a washing liquid.

[0027] Fig.Figure 2 shows a diagram of a first dishwashing program I. Dishwashing program I corresponds to a dishwashing program that many commercially available dishwashers have in the form shown or in a very similar form. The abscissa shows the time t (in minutes) of the dishwashing process, while the ordinate shows the temperature Temp (in degrees Celsius). A dishwashing detergent composition according to the invention was used as the detergent in dishwashing program I, and for comparison, a non-inventive dishwashing detergent A was also used (see Figure 2). Fig.6) In general, the temperature profile over time in a dishwasher's wash chamber (not shown) is depicted over the entire duration of the dishwashing cycle (here, for example, 210 minutes). It should be noted that dishwashing program I serves only as an illustration and can, in principle, last longer or shorter. The volume profile of the washing liquid (here: water) used for dishwashing is also shown along the x-axis. The amounts of washing liquid added to and pumped out during the cycle are given in liters on the y-axis. Dishwashing program I shown for washing dishes thus corresponds to a typical "50 °C program" or "Eco 50" program of standard dishwashers.

[0028] In the illustrated embodiment, 25 ml of the dishwashing composition according to the invention are added to the existing volume of wash liquid after approximately 13 minutes, i.e., after the end of a pre-rinse cycle (arrow aa), meaning before the temperature in the dishwasher's wash chamber rises. Instead, the dishwashing composition is added to a wash liquid at approximately room temperature (about 20-25°C). From this point on, the wash liquid can also be referred to as the rinse solution. Subsequently, the temperature of the wash liquid rises due to heating, and with it the temperature in the wash chamber, to approximately 55°C, and then drops again to approximately 30°C. During this time, the dishes are washed with the wash liquid and the dishwashing composition according to the invention.At the end of the wash cycle, the wash liquid is completely pumped out, followed by an intermediate cleaning with approximately 2.7 liters of fresh wash liquid without any added detergent. After this intermediate cleaning, the wash liquid is pumped out again, and another 2.7 liters of fresh wash liquid are added. At this point, the temperature of the wash liquid, and consequently the wash chamber, is increased to approximately 70°C. At the point in the dishwasher program indicated by arrow Ib, a rinse aid is added to perform a final rinse. Finally, the wash liquid is completely pumped out, and the cleaned dishes are dried at a decreasing temperature until the wash cycle is complete, after approximately 210 minutes.

[0029] Fig.Figure 3 shows a diagram of a second dishwashing program II according to the invention. The general sequence of dishwashing program II with regard to temperature profile and washing liquid handling corresponds to the first dishwashing program I. As in the first example, a dishwashing composition according to the invention with the ingredients specified in Table 1 is used as the dishwashing agent: Table 1: Dishwashing composition according to the invention ingredient function Percentage (by weight) from until Water solvent 34,74 52,1 MGDA Chelating agents 25 50 Propylene glycol binder 4 6 C11E022 non-ionic surfactant 1,6 2,4 Xanthan Thickening agent (viscosity regulator) 0,08 0,12 Itaconic acid Chelating agents and binders 0,8 1,2 Sorbitol binder 1,6 2,4 Sodium polyacrylate binder 4 6 Zinc acetate Glass protection 0,8 1,2 citric acid pH buffer 0,8 1,2 Protease enzyme Hydrolysis of peptide bonds 2,8 4,2 Amilase enzyme Hydrolysis of bonds in starch 0,4 0,6 Phenoxyethanol preservatives 0,4 0,6 Dye(s) Color 0,002 0,003 Fragrance(s) aroma 2 drops 4 drops

[0030] It goes without saying that all ingredients always and exclusively complement each other 100%. In particular, water as a solvent is generally added preferably "quantum satis," that is, in the amount necessary or desired for the respective formulation. The amount of colorants and fragrances is also generally freely selectable. Therefore, formulations without colorants and / or fragrances are also possible. In addition to or instead of MGDA, other aminotricarboxylic acids of the general formula (I) can also be used. - R1, R2 and R3 independently are unsubstituted alkyl groups or substituted alkyl groups with chain lengths from C1 to C4; - n is 0 or 1; and - X is an organic substituent, in particular methyl, ethyl, or a combination thereof, or salts thereof. For better comparability, the total amount of dishwashing composition added is also 25 ml, but can vary depending on the wash chamber size, the volume of wash liquid, the number of dishes to be cleaned, the wash program, etc. Another difference from the first dishwashing program I is that the dishwashing composition according to the invention is only added to the wash liquid at time IIa. At this time, the temperature Temp of the wash liquid has already been heated to at least 40 °C. In other words, the dosage only occurs when the water or wash liquid is already heating up and has reached a temperature of more than 40 °C, e.g., 50 °C (here approximately 30 minutes after the program starts).This results in a surprising synergistic effect of the dishwashing composition according to the invention with an unusually high proportion of aminotricarboxylic acids of general formula (I) and an unusually high addition temperature, leading to a surprisingly significantly improved chemical activity of the complexing agent MGDA (or another compound of formula (I)) and, accordingly, to a considerably improved cleaning effect, particularly for tea stains and the like. The further course of the washing program corresponds to that of the first example, so that at time IIb, after completion of the main wash program, a rinse aid is added to the washing liquid, which has already been completely replaced at this point, as part of an optional rinse program. It is understood that the illustrated process orThe dishwashing process shown is for illustrative purposes only, and many variations in temperature profile, wash duration, and amount of wash liquid used, etc., are possible. Different parameter sets and process sequences can be predefined or parameterized in different dishwasher programs, for example.

[0031] Fig.Figure 4 shows a diagram of a third dishwashing program III, also according to the invention. In contrast to the previous dishwashing program II, the dishwashing composition according to the invention is added in two batches. The first batch, which has a weight fraction of approximately 20% based on the total weight of the dishwashing composition to be added, is added according to arrow IIIa after about 13 minutes and thus before the temperature of the wash liquid increases, while the second batch, i.e., the remaining approximately 80% of the dishwashing composition to be added, is added according to arrow IIIb only after a time interval (here: about 17 minutes) or only when the temperature Temp of the wash liquid is at least 40 °C. The dishwashing composition is preferably added by means of a dosing system of a dishwasher (not shown).The dosing system is coupled to a control unit of the dishwasher, which is designed to control and / or regulate the dosing system. Preferably, the control unit determines at least the temperature of the washing liquid (and possibly other parameters) and doses the dishwashing liquid composition depending on the temperature and, if necessary, time.

[0032] Fig. Figure 5 shows a diagram of the performance values ​​P for tea stain removal of the three in Fig. 2 to Fig.The four dishwashing programs shown are labeled with the Roman numerals I, II, and III. These tests were also carried out in accordance with DIN EN 60436. The improved performance in removing tea stains is evident when the dishwashing composition according to the invention is added at temperatures above 40°C (dishwashing programs II and III) compared to adding it completely at lower temperatures, i.e., at the beginning of the dishwashing process (dishwashing program I). If the dishwashing composition is added for the first time at approximately 40–50°C (program II), the effectiveness on tea stains increases by 43%, that is, from 1.35 points to 2.16 out of a possible 5 performance points P.Further experimental tests have shown that the effect of this “high-temperature dosage” occurs only to a lesser extent at concentrations of the aminotricarboxylic acid of general formula (I) of less than 25% based on the total mass of the dishwashing composition according to the invention, and practically not at all below about 22%.

[0033] Fig.Figure 6 shows a diagram of the performance values ​​P of the dishwashing composition according to the invention when used in one of the dishwashing programs II, III described above, in comparison to commercially available, non-inventive liquid detergents A, B, C, each used in a non-inventive dishwashing program I. Besides the different composition of the dishwashing composition according to the invention, the timing of the addition is also important for the cleaning performance, as already mentioned. Therefore, according to dishwashing programs II, III, the dishwashing compositions according to the invention are added, at least predominantly, only at elevated temperatures of at least 40 °C and preferably at about 50 °C. In contrast, according to dishwashing program I, the commercially available liquid detergents A, B, C are added to the still-cold wash liquid early on, before the heating process has begun.It can be seen that the commercially available liquid detergents A, B, C deliver performance values ​​P of approximately 4 points (4.03 points, 4.07 points, 3.98 points), while the dishwashing composition according to the invention delivers significantly improved performance values ​​P of 4.41 and 4.36 points respectively within the framework of the dishwashing programs II and II according to the invention.

[0034] In summary, the dishwashing composition and the dishwashing method according to the invention offer numerous advantages. The dishwashing composition according to the invention is significantly more effective than all conventional dishwashing detergents on the market, at least with regard to its ability to remove tea stains and the like. The stability of the dishwashing composition according to the invention under thermal stress during storage in a dishwasher with an automatic dosing system is high and therefore sufficient even for long-term storage. A single or batch dose of the dishwashing composition according to the invention at elevated temperatures of at least 40 °C (dishwashing programs II and III, e.g., at approximately 50 °C) increases the effectiveness of the chelating agent of formula (I) and thus significantly improves the removal of tea stains.To avoid delays in the alkalization of the washing liquid to the rinse solution, adding approximately 20% of the dishwashing composition according to the invention before the temperature increase leads, in some situations, to improved performance in removing other types of soiling, such as milk and margarine (dishwashing program III). The dishwashing composition according to the invention can be formulated as a liquid and, due to its high chelating capacity and the synergistic effect of increased addition temperature and increased chelating capacity, has great potential for use in automatically controlled and / or regulated dosing systems of dishwashers.

[0035] The parameter values ​​specified in the documents for defining process and measurement conditions for characterizing specific properties of the subject matter of the invention are to be regarded as being within the scope of the invention even in the event of deviations, for example due to measurement errors, system errors, weighing errors, DIN tolerances and the like. Reference symbol list P Performance score (0-5 points) Temperature (°C) t Time (minutes) I, II, III dishwashing program A, B, C commercially available liquid dishwashing liquids Ia, IIa, IIIa, IIIb Addition time dishwashing composition Ib, IIb, IIIc Time of addition of rinse aid

Claims

[1] Dishwashing composition for cleaning dishes, containing between 22% and 60% by weight of an aminotricarboxylic acid and / or a salt thereof, wherein the aminotricarboxylic acid has the general formula (I) in which - R1, R2 and R3 independently are unsubstituted alkyl groups or substituted alkyl groups with chain lengths from C1 to C4; - n is 0 or 1; and - X is an organic substituent, in particular methyl, ethyl or a combination thereof. [2] Dishwashing composition according to claim 1, wherein the aminotricarboxylic acid of general formula (I) is methylglycine diacetic acid and / or a sodium and / or potassium salt thereof. [3] Dishwashing composition according to claim 1 or 2, wherein the proportion of the aminotricarboxylic acid of general formula (I) and / or the salt thereof in the total mass of the dishwashing composition is between 25 wt.% and 50 wt.%. [4] Dishwashing composition according to any one of claims 1 to 3, wherein the latter additionally comprises at least one auxiliary substance, the auxiliary substance being selected from a group comprising water, binders, surfactants, in particular non-ionic surfactants, thickeners, chelating agents, superabsorbents, glass protectants, pH buffers, anti-scaling agents, oxygen bleaching agents, bleach activators, sequestering agents, corrosion inhibitors, antifoaming agents, protease enzymes, amylase enzymes, lipase enzymes, preservatives, colorants, perfumes and any mixtures thereof. [5] Dishwashing composition according to claim 4, comprising in weight percent: - between 30% and 60%, especially between 34% and 53% water; - between 22% and 60%, in particular between 25% and 50% of the aminotricarboxylic acid according to formula (I) and / or a salt thereof; - between 3% and 7%, especially between 4% and 6% binder; - between 1.5% and 2.5%, in particular between 1.6% and 2.4% surfactant; - between 0.07% and 0.15%, in particular between 0.08% and 0.12% thickening agent; - between 0.07% and 1.5%, especially between 0.8% and 1.2% chelating agents; - between 1.5% and 2.5%, in particular between 1.6% and 2.4% binder; - between 3% and 7%, especially between 4% and 6% superabsorbent polymers; - between 0.07% and 0.15%, in particular between 0.08% and 0.12% glass protectant; - pH buffer between 0.07% and 0.15%, especially between 0.08% and 0.12%; - between 2.7% and 4.5%, especially between 2.8% and 4.2% protease enzymes; - between 0.3% and 0.7%, especially between 0.4% and 0.6% amylase enzymes; - between 0.3% and 0.7%, in particular between 0.4% and 0.6% preservatives; and optionally - at least one dye and / or at least one fragrance. [6] Dishwashing composition according to any one of claims 1 to 5, which is formulated in powder form, in tablet form or in liquid form. [7] Method for washing dishes, comprising washing the dishes with a washing liquid which comprises a dishwashing composition according to any one of claims 1 to 6. [8] Method according to claim 7, wherein the dishwashing composition is added discontinuously to the washing liquid in two or more batches. [9] Method according to claim 8, wherein a first batch of the dishwashing composition is added to the washing liquid in a weight fraction between 10 wt.% and 30 wt.%, in particular about 20 wt.% of a total weight of the dishwashing composition to be added, and / or wherein a second batch of the dishwashing composition is added to the washing liquid in a weight fraction between 90 wt.% and 70 wt.%, in particular about 80 wt.% of a total weight of the dishwashing composition to be added, and / or wherein successive batches of the dishwashing composition are added to the washing liquid at intervals of at least 5 minutes, in particular between about 15 minutes and about 20 minutes. [10] Method according to one of claims 7 to 9, wherein the dishwashing composition is added to the washing liquid for the first time, at least partially, when the washing liquid has been heated to at least 35 °C, in particular at least 40 °C, and / or wherein at least a remainder of the dishwashing composition is added to the washing liquid at the latest when the washing liquid has been heated to a temperature between about 48 °C and about 55 °C. [11] Method according to any one of claims 7 to 10, which is carried out using a dishwasher. [12] Method according to claim 11, wherein the dishwashing composition is added to the washing liquid at the earliest after completion of a pre-rinse program of the dishwasher and / or before a rinse program of the dishwasher. [13] Method according to one of claims 11 or 12, wherein the dishwashing composition is added to the washing liquid by means of a dosing system of the dishwasher, the dosing system adding the dishwashing composition depending on at least one parameter determined by a control device of the dishwasher from the group consisting of temperature of the washing liquid, volume of the washing liquid, total quantity of the dishwashing composition, current process status of a washing program to be carried out, degree of soiling of the dishes, hardness of the washing liquid, batch number of the dishwashing composition, batch proportion of the total quantity of the dishwashing composition and addition rate of the dishwashing composition. [14] Dishwasher for washing dishes, comprising a washing chamber in which the dishes can be exposed to a washing liquid, comprising at least one dosing chamber for a dishwashing composition according to one of claims 1 to 6, comprising a dosing system which is configured to add the dishwashing composition to the washing liquid, and comprising a control device which is configured to control and / or regulate the dishwasher so that it carries out a method according to one of claims 7 to 13.

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