Rinse aid for automatic dishwashers

Abstract

The invention relates to a rinse aid for machine dishwashing or automatic dishwashers, containing, based on the total weight of the dishwashing agent, 3.0 to 15.0 wt.% of a surfactant mixture as defined herein, and 0.01 to 3.0 wt.% of a zinc salt, furthermore the use of these dishwashing agents to reduce damage to decorations, such as decoration, in particular overglaze decoration, imprints and / or metal decoration (e.g. gold and / or silver rims), on the items being washed, and a method for washing dishes using these dishwashing agents.

Description

[0001] The invention relates to a rinse aid for machine dishwashing or automatic dishwashers, containing, based on the total weight of the dishwashing agent, 3.0 to 15.0 wt.% of a surfactant mixture as defined herein, and 0.01 to 3.0 wt.% of a zinc salt, furthermore the use of these dishwashing agents to reduce damage to decorations, such as decorations, prints and / or metal decorations (e.g. gold and / or silver rims), on the items being washed, and a method for washing dishes using these dishwashing agents.

[0002] Today, higher standards are often placed on machine-washed dishes than on hand-washed ones. After machine washing, dishes should not only be free of food residue, but also free of whitish spots caused by water hardness or other mineral salts, which, due to the lack of wetting agents, result from dried water droplets. Such spots and streaks can be observed on virtually any surface (porcelain, glass, plastic, stainless steel). Consumers place particular emphasis on shine and spotlessness, especially for dishes not used daily but for special occasions. These dishes are often treated by hand afterward, which is not very user-friendly.

[0003] Furthermore, it is important for consumers that plastic items and decorations, such as overglaze decorations, prints, and / or metal decorations (e.g., gold and / or silver rims), are adequately protected from damage. This damage is usually caused by ingredients in dishwashing detergents used in the main wash cycle, for example, aminocarboxylates and / or alkali carriers such as alkali metal hydroxides.

[0004] Therefore, there is a need for rinse aids for machine dishwashing that protect, preserve and / or reduce damage to plastic items and / or decorations on the items, such as decorations, especially overglaze decorations, prints and / or metal decorations (e.g. gold and / or silver rims).

[0005] It was surprisingly discovered that a combination of surfactants and zinc salt makes it possible to reduce damage to plastic and / or decorations, such as decorations, especially overglaze decorations, prints and / or gold rims, caused by aggressive ingredients in the main wash cycle, particularly through their addition in the rinse cycle, thus reducing damage to decorations, such as decorations, especially overglaze decorations, prints and / or metal decorations (e.g., gold and / or silver rims), on the items being washed.

[0006] Furthermore, it has now been surprisingly found that the combination of nonionic surfactants used according to the invention in rinse aid formulations for dishwashing results in improved film formation on the surfaces of the items being washed. This allows the water to run off the items in a thin, continuous film, so that no water droplets, streaks, or films remain after the subsequent drying process. This suppresses streaking on the items and significantly improves drying and rinsing performance. In addition, the formulations according to the invention exhibit improved storage stability, particularly when used in the ratios specified in the invention.By using a low proportion of surfactants in the rinse aids according to the invention and by applying the ratio of surfactants to each other according to the invention, it is possible to significantly limit the amount of foam formed during the washing process.

[0007] The problem underlying the present invention was therefore solved by a rinse aid for machine dishwashing or a rinse aid for automatic dishwashers, containing, based on the total weight of the rinse aid, 3.0 to 15.0 wt.%, preferably 5.0 to 12.0 wt.%, more preferably 6.0 to 10.0 wt.% of a surfactant mixture comprising: (i) at least one non-ionic fatty alcohol alkoxylate of formula R 1 O[CH2CHR 3 O] x H, where R 1for a linear or branched, saturated alkyl group with 10 to 18 carbon atoms, preferably 12 to 16 carbon atoms, more preferably 13 to 15 carbon atoms, each R 3 independent for -H or -CH2CH3 and x for 10-20, wherein at least one, preferably at least 5, more preferably at least 9 or 10 R 3 H and at least one or two R 3 CH2CH3 are; and (ii) at least one non-ionic fatty alcohol ethoxylate of formula R 2 O[CH2CH2O] y H, where R 2for a linear or branched saturated alkyl group having 10 to 18 carbon atoms, preferably 12 to 18 carbon atoms, and y represents integers from 3 to 12, preferably from 4 to 10, more preferably from 6 to 8, wherein the mass ratio of the at least one non-ionic surfactant (i) to the at least one non-ionic surfactant (ii) is in the range of 2:1 to 1:5, preferably from 1.5:1 to 1:3, particularly preferably from 1:1 to 1:2, characterized in that it contains at least one zinc salt in an amount of 0.01 to 3 wt.%.

[0008] The present invention also relates to the use of a rinse aid according to the invention in a machine dishwashing process, in particular its use to improve the rinsing performance when cleaning dishes in an automatic dishwasher.

[0009] Another object of the invention is a machine dishwashing process in which a rinse aid according to the invention is used, in particular for the purpose of improving the rinsing performance and at the same time the protection of plastic and / or decorations.

[0010] The present application also concerns the use of a rinse aid composition according to the invention to improve the rinse aid performance while simultaneously protecting plastic and decorations.

[0011] Another particular subject matter of the present application is the use of a rinse aid composition according to the invention for protecting and / or reducing damage to plastic and / or decorations, such as decoration, in particular overglaze decoration, imprints and / or metal decoration (e.g. gold and / or silver rims), which are located on the dishwashing items, hereinafter referred to as decorations.

[0012] Surprisingly, the following types of damage to decorations, such as color loss, discoloration, fading, or even peeling, are significantly reduced. According to the invention, decorations are better protected against color loss, discoloration, fading, and / or peeling. This results in less damage (better protection) to decorations on the dishes, especially overglaze decorations, prints, and / or metallic decorations (e.g., gold and / or silver rims), particularly on ceramics, porcelain, stoneware, and / or glassware. At the same time, the rinse aids according to the invention also better protect plastic dishes from damage such as roughening, graying, or clouding. Decorations on plastic are also less affected and better protected.

[0013] Another subject of the present application is a machine dishwashing process using a rinse aid according to the invention.

[0014] Finally, the use of the rinse aids according to the invention to improve the rinsing performance while simultaneously protecting plastic and / or decorations during machine dishwashing is also the subject of the present invention.

[0015] These and other aspects, features, and advantages of the invention will become apparent to the person skilled in the art upon studying the following detailed description and claims. Each feature from one aspect of the invention can be incorporated into any other aspect of the invention. Furthermore, it is understood that the examples contained herein are intended to describe and illustrate the invention, but do not limit it, and in particular, the invention is not limited to these examples. Numerical ranges specified in the format "from x to y" include the stated values. If several preferred numerical ranges are specified in this format, it is understood that all ranges resulting from the combination of the different endpoints are also covered.

[0016] "At least one," as used herein, means one or more, i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, or more. When referring to an ingredient, the statement refers to the type of ingredient and not the absolute number of molecules. Thus, "at least one nonionic surfactant," for example, means at least one type of nonionic surfactant, i.e., it could refer to one type of nonionic surfactant or a mixture of several different nonionic surfactants. When used with weight specifications, the statement refers to all compounds of the specified type contained in the composition / mixture, i.e., the composition contains no further compounds of that type beyond the specified amount of the relevant compounds.

[0017] The rinse aids described herein are preferably phosphate-free. "Phosphate-free," as used herein, means that the composition in question is essentially free of phosphates, i.e., phosphates are not intentionally added, and in particular, phosphates are present in amounts of less than 1% by weight, preferably less than 0.1% by weight, based on the total composition. Accordingly, "free from," as used herein, means that the relevant substance is present in amounts of less than 1% by weight, preferably less than 0.1% by weight, and even more preferably less than 0.01% by weight, based on the total composition. In particular, it also means that the relevant substance is not intentionally added.

[0018] All percentages given in connection with the compositions described herein refer, unless explicitly stated otherwise, to wt%, in each case relating to the respective composition.

[0019] “Approximately” or “ca.”, as used herein in connection with a numerical value, refers to the numerical value ±10%, preferably ±5%.

[0020] Whenever alkaline earth metals are mentioned below as counterions for monovalent anions, this means that the alkaline earth metal is naturally present in only half the amount of substance as the anion, which is sufficient to balance the charge.

[0021] The rinse aids described herein are rinse aid formulations used in addition to the actual cleaning agent formulation. These rinse aid formulations are preferably added or released during the rinse cycle. Besides water as the main solvent and essential component, they may contain other surfactants, as well as typically fragrances and preservatives.

[0022] The rinse aids of the invention contain a surfactant mixture comprising at least two low-foaming non-ionic surfactants from the group of polyoxyalkylated non-ionic surfactants, as defined above.

[0023] The first surfactant is at least a non-ionic fatty alcohol alkoxylate of formula R 1 O[CH2CHR 3 O] x H, where R 1 for a linear or branched, saturated alkyl group with 10 to 18 carbon atoms, preferably 12 to 16 carbon atoms, more preferably 13 to 15 carbon atoms, each R 3 independently stands for -H or -CH2CH3 and x stands for 2-20, wherein at least one, preferably at least 5, more preferably at least 9 or 10 R 3 H and at least one or two R 3CH2CH3. This means that the first surfactant is an ethoxylated / butoxylated fatty alcohol with 10 to 18 carbon atoms in the alkyl group. Among these, surfactants with EO-BO blocks are preferred, wherein one to ten EO or one to two BO groups are bonded together before a block of the other groups follows. Nonionic surfactants of the general formula are particularly preferred. R 1 O[CH2CH2O] x [CH2CH(CH2CH3)O] z H in the R 1 as defined above, but preferably linear, x representing 1 to 20, preferably 9 to 20, more preferably 9 to 15, and z representing 1 to 5, preferably 1 to 2. Thus, nonionic surfactants are particularly preferred, which have a C 13-15 -Alkyl group comprising 1 to 20, preferably 9 to 20, more preferably 9 to 15 ethylene oxide units, followed by 1 to 5, preferably 1 to 2 butylene oxide units.

[0024] Such surfactants are available, for example, from BASF under the trade name Plurafac®. A preferred surfactant is Plurafac® LF220 (BASF SE).

[0025] In various embodiments of the invention, the aforementioned niotenes can also be end-capped, i.e., the terminal hydrogen atom of the hydroxyl group is covered by a C 1-20 Alkyl group, preferably C 1-4 Alkyl residue, replaced.

[0026] The surfactant mixture also includes at least one second nonionic surfactant of the formula R 2 O[CH2CH2O] y H, where R 2 for a linear or branched saturated alkyl group with 10 to 18 carbon atoms, preferably 12 to 18 carbon atoms, and y represents integers from 3 to 12, preferably from 4 to 10, even more preferably from 6 to 8.

[0027] Examples of these non-ionic surfactants include C 12-18 Fatty alcohols with (EO)4-8 , especially C 12-14 Fatty alcohol (EO)6, C 12-18 -Fat alcohol (EO) 6-8 , C 12-18 Fatty alcohol (EO)6 and / or C 12-18 -Fatty alcohol-(EO)7.

[0028] Such surfactants are commercially available from BASF under the trade names Dehydol® LT and Dehydol® LS. Dehydol® LS6 or Dehydol LT7 (BASF SE) or a mixture thereof is particularly preferred.

[0029] The mass ratio of the at least one non-ionic ethoxylated / butoxylated surfactant to the at least one non-ionic ethoxylated surfactant, i.e., of surfactant (i) to surfactant (ii), is in the range of 2:1 to 1:5, preferably in the range of 1.5:1 to 1:3, more preferably 1:1 to 1:2, and particularly 3:5. The amount of surfactant (i) relative to the total weight of the composition is preferably from 1 to 10 wt.%, more preferably 1.5 to 4 wt.%.

[0030] Particularly preferred is a combination of nonionic surfactants according to i) preferably such fatty alcohol alkoxylates which have a C 13-15 -Alkyl group comprising 1 to 20, preferably 9 to 20, more preferably 9 to 15 ethylene oxide units, followed by 1 to 5, preferably 1 to 2 butylene oxide units, with nonionic surfactants according to ii), preferably C 12-18 Fatty alcohols with (EO) 3-10 , especially preferred C 12-18 Fatty alcohols with (EO) 4-8 , especially C 12-14 Fatty alcohol (EO)6, C 12-18 -Fat alcohol (EO) 6-8 , C 12-18 Fatty alcohol (EO)6 and / or C 12-18 Fatty alcohol (EO)7 or mixtures thereof, in a mass ratio of preferably 1:4 to 7:8, particularly 2:3. The amount based on the total weight of the composition is preferably 1 to 10 wt.%, preferably 3 to 5 wt.% for surfactant (i) and preferably 1 to 10 wt.%, preferably 3 to 6 wt.% for surfactant (ii).

[0031] The rinse aids according to the invention can contain, in addition to the aforementioned non-ionic surfactants, further surfactants in the surfactant mixture, in particular further non-ionic or anionic surfactants, but also cationic or amphoteric surfactants.

[0032] Other suitable non-ionic surfactants include, for example, alkyl glycosides, alkoxylated, preferably ethoxylated or ethoxylated and propoxylated fatty acid alkyl esters, but also non-ionic surfactants of the amine oxide type. The amount of these non-ionic surfactants is preferably no more than that of the alkoxylated fatty alcohols, and in particular not more than half of it. In various embodiments, however, the rinse aids of the invention contain no non-ionic surfactants other than the surfactants (i) and (ii) described according to the invention.

[0033] All anionic surfactants are suitable. Preferred anionic surfactants include fatty alcohol sulfates, fatty alcohol ether sulfates, dialkyl ether sulfates, monoglyceride sulfates, alkylbenzenesulfonates, olefin sulfonates, alkanesulfonates, ethersulfonates, n-alkyl ethersulfonates, estersulfonates, and lignosulfonates. Also suitable are fatty acid cyanamides, sulfosuccinates (sulfosuccinic acid esters), especially mono- and dialkyl sulfosuccinic acid esters with 8 to 18 carbon atoms, sulfosuccinamates, sulfosuccinamides, fatty acid isethionates, acylaminoalkanesulfonates (fatty acid taurides), fatty acid sarcosinates, ether carboxylic acids and alkyl (ether) phosphates, as well as α-sulfofatisfied acid salts, acylglutamates, monoglyceride disulfates, and alkyl ethers of glycerin disulfate. In preferred embodiments, however, the rinse aids of the invention are free of anionic surfactants.

[0034] The rinse aid of the present invention contains at least one zinc salt, preferably in an amount of 0.01 to 3 wt.%, more preferably in an amount of 0.02 to 1.0 wt.%, and particularly in an amount of 0.03 to 0.5 wt.% based on the total weight of the composition. The addition of zinc salts leads to reduced glass corrosion and, surprisingly, also has a positive effect on the preservation of decorations and / or protects them from damage.

[0035] The zinc salt preferably used according to the invention is water-soluble, meaning it has a solubility in water above 100 mg / l, preferably above 500 mg / l, particularly preferably above 1 g / l and especially above 5 g / l (all solubilities at a water temperature of 20°C). At least one inorganic and / or one organic zinc salt can be used.

[0036] The inorganic zinc salt is preferably selected from the group consisting of zinc bromide, zinc chloride, zinc iodide, zinc nitrate, and zinc sulfate. The organic zinc salt is preferably selected from the group consisting of zinc salts of monomeric or polymeric organic acids, in particular from the group consisting of zinc acetate, zinc acetylacetonate, zinc PCA (zinc 5-oxopyrrolidine-2-carboxylate), zinc benzoate, zinc chloride, zinc formate, zinc lactate, zinc gluconate, zinc ricinoleate, zinc abietate, zinc valerate, and zinc p-toluenesulfonate.

[0037] In a particularly preferred embodiment according to the invention, at least one zinc salt, in particular a water-soluble zinc salt, is preferably zinc chloride, zinc acetate or zinc sulfate.

[0038] In various preferred embodiments of the rinse aid according to the invention, the pH value of the rinse aid is below 7, preferably from 1.5 to 5, more preferably from 1.8 to 4.5.

[0039] The pH value of the rinse aid according to the invention can be adjusted using conventional pH regulators. In preferred embodiments, the pH value of the rinse aid is selected such that a 1% aqueous solution of the rinse aid at 20 °C has a pH value in the range of 1.5 to 5.0, preferably from 2.0 to 4.5, and particularly preferably from 2.5 to 4.0.

[0040] In general, the pH value of the rinse aid can be adjusted using conventional pH regulators. Acids and / or alkalis serve as pH adjusters. Suitable acids include, in particular, organic acids such as acetic acid, citric acid, glycolic acid, lactic acid, succinic acid, adipic acid, malic acid, tartaric acid, and gluconic acid, or also sulfamic acid. In addition, the mineral acids hydrochloric acid, sulfuric acid, and nitric acid, or mixtures thereof, can also be used. Suitable bases come from the group of alkali and alkaline earth metal hydroxides and carbonates, especially the alkali metal hydroxides, of which potassium hydroxide and, above all, sodium hydroxide are preferred. However, volatile alkalis, for example in the form of ammonia and / or alkanolamines, which can contain up to 9 carbon atoms in the molecule, are particularly preferred. The alkanolamine is preferably selected from the group consisting of mono-, di-, triethanololamine, and propanolamine, and mixtures thereof.

[0041] To adjust and / or stabilize the pH value, the rinse aid according to the invention can also contain one or more buffering agents (INCI Buffering Agents), typically in amounts of 0.001 to 5% by weight. Buffering agents that are also complexing agents or even chelating agents (CHELizers, INCI Chelating Agents) are preferred. Particularly preferred buffering agents are citric acid or citrates, especially sodium and potassium citrates, for example trisodium citrate dihydrate and tripotassium citrate dihydrate.

[0042] The rinse aids according to the invention can contain at least one, preferably two or more, further components, preferably selected from the group consisting of builders, enzymes, thickeners, sequestrants, electrolytes, corrosion inhibitors, in particular silver protectants, glass corrosion inhibitors, polymers, bleaching agents, bleach activators, foam inhibitors, dyes, fragrances, bittering agents, and antimicrobial agents. Suitable components are known to those skilled in the art. Common components of rinse aid formulations are, in particular, fragrances and antimicrobial agents (preservatives), as well as optionally soluble builders, in particular organic builders.

[0043] If builders are used, soluble organic builders are particularly suitable. Examples of suitable organic builders include polycarboxylic acids, which can be used in the form of the free acid and / or its sodium salts. Polycarboxylic acids are defined as carboxylic acids that possess more than one acid function. Examples include citric acid, adipic acid, succinic acid, glutaric acid, malic acid, tartaric acid, maleic acid, fumaric acid, sugar acids, nitrilotriacetic acid (NTA), provided such use is not objectionable for ecological reasons, and mixtures thereof. In addition to their builder effect, the free acids typically also act as an acidifying component and thus serve to adjust the pH of dishwashing detergents to a lower and milder value. Citric acid, succinic acid, glutaric acid, adipic acid, gluconic acid, and any mixtures thereof are particularly relevant in this regard.Another important class of phosphate-free structural materials comprises amino acids and / or their salts. Particularly preferred representatives of this class are methylglycine diacetic acid (MGDA) or its salts, glutamic diacetic acid (GLDA) or its salts, and ethylenediamine diacetic acid (EDDS) or its salts. GLDA and its salts are especially preferred.

[0044] The use of citric acid and / or citrates has proven particularly advantageous for cleaning and rinsing performance. According to the invention, machine dishwashing detergents are therefore preferred, characterized in that the rinse aid contains citric acid or a salt of citric acid, and that the weight fraction of citric acid or the salt of citric acid is preferably 0.5 to 20 wt.%, preferably 1 to 15 wt.%, and particularly 1 to 10 wt.%.

[0045] Within the scope of the present invention, individual odorant compounds, such as synthetic products of the ester, ether, aldehyde, ketone, alcohol, and hydrocarbon type, can be used as perfume oils or fragrances. However, mixtures of different odorants that together produce an appealing fragrance are preferred. Such perfume oils can also contain natural odorant mixtures, such as those available from plant sources, for example, pine, citrus, jasmine, patchouli, rose, or ylang-ylang oil.

[0046] Furthermore, preservatives may be included in the rinse aids. Suitable examples include preservatives from the groups of alcohols, aldehydes, antimicrobial acids and / or their salts, carboxylic acid esters, acid amides, phenols, phenol derivatives, diphenyls, diphenylalkanes, urea derivatives, oxygen and nitrogen acetals and formals, benzamidines, isothiazoles and their derivatives such as isothiazolines and isothiazolinones, phthalimide derivatives, pyridine derivatives, antimicrobial surfactants, guanidines, antimicrobial amphoteric compounds, quinolines, 1,2-dibromo-2,4-dicyanobutane, iodo-2-propynyl butylcarbamate, iodine, iodophors, and peroxides.Preferred antimicrobial agents are preferably selected from the group comprising ethanol, n-propanol, i-propanol, 1,3-butanediol, phenoxyethanol, 1,2-propylene glycol, glycerol, undecylenic acid, citric acid, lactic acid, benzoic acid, salicylic acid, thymol, 2-benzyl-4-chlorophenol, 2,2'-methylene-bis-(6-bromo-4-chlorophenol), 2,4,4'-trichloro-2'-hydroxydiphenyl ether, N-(4-chlorophenyl)-N-(3,4-dichlorophenyl)-urea, N,N'-(1,10-decandiyldi-1-pyridinyl-4-ylidene)-bis-(1-octanamine)-dihydrochloride, N,N'-Bis-(4-chlorophenyl)-3,12-diimino-2,4,11,13-tetraazatetradecanediimidamide, antimicrobial quaternary surfactants, guanidines. Particularly preferred preservatives, however, are selected from the group comprising salicylic acid, quaternary surfactants, especially benzalkonium chloride and isothiazoles and their derivatives such as isothiazolines and isothiazolinones.

[0047] Solvents suitable for the compositions used according to the invention are, besides water as the preferred solvent, generally water-miscible organic solvents such as, for example, without limitation, ethanol, propanol, 1,2-propanediol and glycerin.

[0048] In general, the formulation of the rinse aids described herein can be carried out in various ways. The rinse aids can be in solid or liquid form, or as a combination of solid and liquid forms. Suitable solid forms include powders, granules, extrudates, compacts, and especially tablets. Liquid forms based on water and / or organic solvents can be thickened or in gel form. The rinse aids can be formulated as single-phase or multi-phase products. The individual phases of multi-phase rinse aids can have the same or different states of matter.

[0049] “Liquid”, as used herein in reference to the rinse aid according to the invention, therefore includes all flowable compositions and in particular also covers gels and pasty compositions.

[0050] The rinse aids described herein are preferably rinse aids for machine dishwashing and are in liquid form.

[0051] In further preferred embodiments, the amount of a dosing unit of the rinse aid is from 0.1 to 10 ml, preferably from 0.1 to 8 ml, and even more preferably from 2.5 to 5.5 ml.

[0052] The preferred total amount of surfactant used in the rinse cycle of a dishwasher is 0.05 to 1 g / job, preferably 0.08 to 0.6 g / job, in particular 0.12 to 0.5 g / job, for example 0.18 to 0.4 g / job.

[0053] Although not preferred, the rinse aids described herein can be pre-assembled into dosing units. These dosing units preferably comprise the amount of cleaning agents necessary for one cleaning cycle. The volume of the dosing unit is preferably from 0.1 to 10 ml, more preferably from 0.1 to 8 ml, and particularly preferably from 2.5 to 5.5 ml. In such embodiments, the pre-assembled dosing unit can have a water-soluble coating made of a water-soluble film material. It is preferred that the water-soluble coating contains polyvinyl alcohol or a polyvinyl alcohol copolymer. Water-soluble coatings containing polyvinyl alcohol or a polyvinyl alcohol copolymer exhibit good stability with sufficiently high water solubility, particularly cold water solubility.Suitable water-soluble films for producing the water-soluble coating are preferably based on a polyvinyl alcohol or a polyvinyl alcohol copolymer and are known in the prior art.

[0054] The use of the rinse aids according to the invention in machine dishwashing is also part of the invention. This particularly includes their use to improve the rinsing performance when cleaning dishes in an automatic dishwasher.

[0055] The invention also relates to a dishwashing method, in particular a machine dishwashing method, in which a rinse aid according to the invention is used, especially for the purpose of improving the rinsing performance. The present application therefore further relates to a method for cleaning dishes in a dishwasher, in which the rinse aid according to the invention is dosed into the interior of a dishwasher during the execution of a dishwashing program. The dosing or introduction of the rinse aid according to the invention into the interior of the dishwasher can be carried out manually; however, the rinse aid is preferably dosed into the interior of the dishwasher by means of the dosing chamber.

[0056] Finally, the use of the surfactant mixture employed according to the invention to improve the rinsing performance in machine dishwashing is also the subject of the present invention.

[0057] A particularly preferred embodiment is a machine dishwashing process characterized in that a rinse aid, as described above, with a total surfactant quantity of 0.05 to 1 g / job, preferably 0.08 to 0.6 g / job, in particular 0.12 to 0.5 g / job, for example 0.18 to 0.4 g / job, and a zinc salt quantity of 0.003 to 0.5 g / job, in particular 0.001 to 0.05 g / job, is used, preferably in the rinse cycle.

[0058] Typical cleaning cycles in machine dishwashing processes can include one or more pre-rinse cycles and include one or more cleaning cycles, preferably one cleaning cycle, as well as one or more rinsing cycles, preferably one rinsing cycle.

[0059] Preferably, machine dishwashing processes are used in which the cleaning cycle takes place at a temperature in the range of 30 °C to 70 °C, preferably from 35 °C to 60 °C, particularly preferably from 35 °C to 50 °C, and especially preferably at 40 to 45 °C, and / or the rinsing cycle preferably takes place at a temperature in the range of 45 °C to 80 °C, particularly preferably from 50 °C to 75 °C.

[0060] Another aspect of the present invention is the use of a rinse aid, as described above, to protect plastic and / or decorations, such as decorations, in particular overglaze decorations, prints, and / or metal decorations (e.g., gold and / or silver rims), on the items being washed. For the gentle cleaning of items made of plastic and / or with decorations, the rinse aid according to the invention is used, particularly in the rinse cycle, in mechanical dishwashers. This results in less damage to decorations on the dishes, especially on porcelain plates with decorations, particularly overglaze decorations, or on glasses with decorations. In long-term tests, in which the items were washed more than one hundred times, and in particular more than two hundred times, a lower degree of decoration damage, especially to overglaze decorations, was observed compared to wash cycles without a rinse aid.Color loss, discoloration, fading, or even peeling of the decoration is reduced or significantly diminished. The rinse aids according to the invention are used to reduce damage to decorations on porcelain, plastic, and / or glass, particularly while simultaneously providing good rinsing performance, meaning that little spotting or filming is observed.

[0061] The use and / or procedure is governed accordingly by the information disclosed above specifically for the cleaning agents.

[0062] The embodiments described in the context of the rinsing agents according to the invention can readily be transferred to the methods and uses according to the invention and vice versa.

[0063] Example implementation: The rinse tests were carried out in a Miele GSL2 with the program RT65°C / 30min / Kl65°C at a water hardness of 0-1°dH (0 to 0.2 mmol (calcium and magnesium ions) / I). Each test run was conducted in the presence of 50 g of ballast dirt (containing ketchup, mustard, Gravy, potato starch, margarine, egg yolk and milk) was carried out, which was dosed at the beginning of each main wash cycle.

[0064] To test the impairment of decoration, in addition to other tableware and cutlery items, two porcelain dessert plates with decoration, especially with overglaze decorations, from different manufacturers, as well as two multicolored decorated drinking glasses (soda glass) were used.

[0065] The grades, from 1 to 5 (where 5 = no impairment of the decoration to 1 = very severe impairment of the decoration), were determined by trained personnel in a display case under natural daylight and artificial light (halogen spotlights). Cotton gloves were worn to prevent any distortion of the results.

[0066] For each wash cycle, 20 g of solid detergent (IEC-D Reference Detergent) and, if necessary, an additional 3 ml of the composition according to the invention as shown in Table 1 were used. Table 1: Rinse aid

[0067] The following information refers to wt% active substance based on total weight (unless otherwise stated). ingredient % by weight Trisodium citrate (anhydrous) 1,2 Plurafac LF 220 3,0 Dehydol LS 6 5,15 Formic acid 75% in water 0,65 Zinc acetate anhydrate 0,1 Perfume, optional 0,1 Water Ad 100

[0068] Various glasses, stainless steel knives, polypropylene and polyethylene plastic containers, as well as decorative glasses and plates with printed designs, were washed 200 times consecutively, as described above. The corrosion on the items was examined after the 200 wash cycles were completed.

[0069] The items being washed were visually evaluated by comparison with a reference scale (5 = no corrosion; 1 = very severe corrosion). A difference of 0.5 was considered significant. Table 2: Results after 200 rinsing cycles: plastic decor Steel Standard dishwashing liquid 1,9 3,3 5,0 Standard dishwashing liquid and rinse aid 2,4 4,4 5,0

[0070] As expected, no damage was found on steel knives, but surprisingly it was found that using the rinse aid in addition to the standard dishwashing detergent leads to a significant reduction in material wear, especially of decoration, on plastic and decorated dishes.

Claims

Rinse aid for machine dishwashing, comprising, based on the total weight of the rinse aid, 3.0 to 15.0 wt.%, preferably 5.0 to 12.0 wt.%, more preferably 6.0 to 10.0 wt.% of a surfactant mixture comprising: (i) at least one non-ionic fatty alcohol alkoxylate of the formula R1O[CH2CHR3O]xH, wherein R1 represents a linear or branched saturated alkyl group having 10 to 18 carbon atoms, preferably 12 to 16 carbon atoms, more preferably 13 to 15 carbon atoms, each R3 independently representing -H or -CH2CH3, and x representing 10-20, wherein at least one, preferably at least 5, more preferably at least 9 or 10 are R3H and at least one or two are R3CH2CH3;and (ii) at least one non-ionic fatty alcohol ethoxylate of the formula R2O[CH2CH2O]yH, wherein R2 represents a linear or branched saturated alkyl group having 10 to 18 carbon atoms, preferably 12 to 18 carbon atoms, and y represents integers from 3 to 12, preferably from 4 to 10, more preferably from 6 to 8, wherein the mass ratio of the at least one non-ionic surfactant (i) to the at least one non-ionic surfactant (ii) is in the range of 2:1 to 1:5, preferably from 1.5:1 to 1:3, particularly preferably from 1:1 to 1:2, characterized in that it contains at least one zinc salt in an amount of 0.01 to 3 wt.%. Rinse aid according to claim 1, characterized in that surfactant (i) is a compound of the formula R1O[CH2CH2O]x[CH2CH(CH2CH3)O]zH, in which R1 is defined as above, in particular a C13-15 alkyl group, x stands for 1 to 20, preferably 9 to 20, more preferably 9 to 15, and z stands for 1 to 5, preferably 1 to 2. Rinse aid according to claim 1 or 2, characterized in that surfactant (ii) is a C12-18 fatty alcohol with (EO)4-8, in particular C12-14 fatty alcohol-(EO)6, C12-18 fatty alcohol-(EO)6-8, C12-18 fatty alcohol-(EO)6 and / or C12-18 fatty alcohol-(EO)7. Rinse aid according to one of claims 1 to 3, characterized in that it contains at least one zinc salt in an amount of 0.02 to 1 wt.%, preferably in an amount of 0.03 to 0.5 wt.%, in each case based on the total weight of the composition. Rinse aid according to any one of claims 1 to 4, characterized in that the zinc salt is selected from the group consisting of zinc bromide, zinc chloride, zinc iodide, zinc nitrate, zinc sulfate, zinc acetate, zinc acetylacetonate, zinc PCA (zinc 5-oxopyrrolidine-2-carboxylate), zinc benzoate, zinc chloride, zinc formate, zinc lactate, zinc gluconate, zinc ricinoleate, zinc abietate, zinc valerate and zinc p-toluenesulfonate, in particular from the group consisting of zinc chloride, zinc acetate or zinc sulfate, particularly preferably zinc acetate. Rinse aid according to one of claims 1 to 5, characterized in that the pH value of the rinse aid is below 7, preferably from 1.5 to 5, more preferably from 1.8 to 4.

5. Rinse aid according to one of claims 1 to 6, characterized in that a dosage unit of the rinse aid is from 0.1 to 10 ml, preferably from 0.1 to 8 ml, more preferably from 2.5 to 5.5 ml. Rinse aid according to one of claims 1 to 7, characterized in that, based on the total weight of the composition, the surfactant (i) is contained in an amount of 1 to 10 wt.%, preferably 1.5 to 4 wt.% and / or the surfactant (ii) is contained in an amount of 1 to 10 wt.%, preferably 3 to 6 wt.%. Rinse aid according to one of claims 1 to 8, characterized in that the surfactant mixture contains further surfactants, in particular further non-ionic, anionic, cationic and / or amphoteric surfactants, and / or the rinse aid contains at least one further component, preferably at least two further components, selected from the group consisting of builders, enzymes, thickeners, sequestrants, electrolytes, corrosion inhibitors, in particular silver protectants, glass corrosion inhibitors, polymers, bleaching agents, bleach activators, foam inhibitors, dyes, perfumes, bittering agents and antimicrobial agents. Dishwashing method, in particular a machine dishwashing method, characterized in that a rinse aid according to one of claims 1 to 9 is used. A machine dishwashing method according to claim 10, characterized in that a rinse aid according to one of claims 1 to 8 is used, comprising a total surfactant quantity of 0.05 to 1 g / job, preferably 0.08 to 0.6 g / job, in particular 0.12 to 0.5 g / job, for example 0.18 to 0.4 g / job, and a zinc salt quantity of 0.0003 to 0.5 g / job, in particular 0.001 to 0.05 g / job, preferably in the rinse cycle. Use of a rinse aid according to one of claims 1 to 9 in a machine dishwashing process for protecting plastic and / or decorations, such as decoration, in particular overglaze decoration, prints and / or metal decoration (e.g. gold and / or silver rims), on the dishwashing items.