Dishwashing composition

Abstract

The present invention is related to a dishwashing, preferably an automatic dishwashing, composition, wherein the composition comprises a 1,3,4-thiadiazole having the formula (I), wherein R1 = C1–C18 hydrocarbon moiety, NR3R4 moiety, S-R5 moiety, S-S-R6 moiety, H, S- anion with a counterion; wherein R3, R4, R5, and R6 can be identical or different; wherein R3, R4, R5, and R6 = H, C1–C18 hydrocarbon moiety; R2 = C1–C18 hydrocarbon moiety, NR3R4 moiety, S-R5 moiety, S-S-R6 moiety, H, S- anion with a counterion; wherein R3, R4, R5, and R6 can be identical or different; wherein R3, R4, R5, and R6 = H, C1-C18 hydrocarbon moiety; and wherein said two moieties R1 and R2 are identical or different. The invention further relates to the use of such an inventive dishwashing, preferably an automatic dishwashing, composition for silver corrosion protection of silver dishwashing goods; wherein preferably said dishwashing, preferably said automatic dishwashing, composition is a detergent composition or a rinse aid composition.

Description

[0001] DISHWASHING COMPOSITION

[0002] Field of the Invention

[0003] The present invention relates to a dishwashing, preferably an automatic dishwashing, composition.

[0004] The invention further relates to the use of such an inventive dishwashing, preferably an automatic dishwashing, composition for silver corrosion protection of silver dishwashing goods; wherein preferably said dishwashing, preferably said automatic dishwashing, composition is a detergent composition or a rinse aid composition.

[0005] Backqround of the Invention

[0006] Silver is chemically the most reactive element among the noble metals and tarnishes readily.

[0007] Silver discoloration, generally termed tarnishing, is often caused by a silver oxidation process in which compounds are formed on the surface of the material. Food, such as onions, mustard and eggs that contain organic sulphur compounds, are known to tarnish silver.

[0008] Silver tarnishing is also known to occur when an oxygen bleaching agent is used in detergent compositions and oxidizes silver to silver oxide. This oxidation process causes surface blackening of the silverware when it is washed in a machine. The level of tarnishing observed can range from slight discoloration of the silverware to the formation of a dense black coating on the surface of the silverware, depending on the formulation and, more precisely, the type of bleaching agent.

[0009] Such a tarnishing and shine loss of silver items leaves a bad impression to consumers, reduces their satisfaction with the product performance / item appearance and even their purchase intent. Hence, some consumers don't even dare to put their silverware into the dishwasher and prefer to clean them manually.

[0010] The dual challenge in formulating a product is therefore the optimization of the cleaning of bleachable soils while minimizing the occurrence of tarnishing of silverware components.

[0011] The phenomenon of silver tarnishing therefore increased in automatic dishwashers with the widespread introduction of low-alkaline formulations containing oxygen bleaching agents. As consequence, the oxidation potentials were shifted to favor the formation of black silver oxide during the cleaning process. T o suppress this reaction, the concentration of the bleach system had to be optimized, and anti-tarnishing agents, such as benzotriazole (BTA), had to be added.

[0012] However, recent environmental science publications highlighted the alarming biodegradability profile of BTA and some of its derivatives. As a result of their resistance to conventional wastewater treatment procedures, an accumulation of this omnipresent organic micropollutant in the aquatic environment takes place, while it is also a potential endocrine disruptor.

[0013] Thus, inexpensive, environmentally-friendly yet highly active substitute materials are currently being sought in order to replace the currently used toxic compounds.

[0014] In view of the prior art, it was thus an object of the present invention to provide a dishwashing, preferably an automatic dishwashing, composition, which shall not exhibit the aforementioned shortcomings of the known prior art dishwashing compositions.

[0015] In particular, it was an object of the present invention to provide a dishwashing composition comprising a specific silver corrosion inhibition agent, which shall ensure a silver corrosion protection being at least comparable to the commonly used dishwashing compositions comprising benzotriazoles or derivatives thereof.

[0016] Hence, it was an additional object of the present invention to provide an inventive dishwashing composition comprising new biodegradable and sustainable compounds, which are not providing any known risks to the environment or the human health, as well as being easily available on a commercial scale at a reasonable cost.

[0017] Summary of the Invention

[0018] These objects and also further objects which are not stated explicitly but are immediately derivable or discernible from the connections discussed herein by way of introduction are achieved by a dishwashing, preferably an automatic dishwashing, composition having all features of claim 1. Appropriate modifications to the inventive dishwashing, preferably an automatic dishwashing, composition are protected in dependent claims 2 to 14. Claim 15 relates to the use of such an inventive dishwashing, preferably an automatic dishwashing, composition for silver corrosion protection of silver dishwashing goods.

[0019] The present invention accordingly provides a dishwashing, preferably an automatic dishwashing, composition, wherein the composition comprises a 1 ,3,4- thiadiazole having the following formula: wherein

[0020] Ri = Ci - C hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3, R4, Rs, and Re = H, Ci - Cis hydrocarbon moiety;

[0021] R2 = Ci - C hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3, R4, Rs, and Re = H, Ci - C18 hydrocarbon moiety; and wherein said two moieties R1 and R2 are identical or different.

[0022] It is thus possible in an unforeseeable manner to provide a dishwashing, preferably an automatic dishwashing, composition, which does not exhibit the aforementioned shortcomings of the known prior art dishwashing compositions.

[0023] In particular, the dishwashing composition of the present invention provides a dishwashing composition comprising a specific silver corrosion inhibition agent, which ensures a silver corrosion protection being at least comparable to the commonly used dishwashing compositions comprising benzotriazoles or derivatives thereof.

[0024] Hence, the inventive dishwashing composition of the present invention provides an inventive dishwashing composition comprising new biodegradable and sustainable compounds, which are not providing any known risks to the environment or the human health, as well as being easily available on a commercial scale at a reasonable cost.

[0025] The invention hereby describes the utilization of a 1 ,3,4-thiadiazole having the formula of claim 1 in automatic dishwashing (ADW) compositions, especially in ADW detergent or rinse aid compositions. Such compositions including such a small aromatic heterocycle demonstrated surprising anti-tarnishing benefits on silver dishwashing goods.

[0026] According to the safety data sheet, the newly identified compounds further exhibit a safer profile than the current state of the art silver protecting benzotriazoles and, hence, improve the eco-toxicological impact of the current formulation.

[0027] Certain corrosion inhibitors can adsorb and complex on the silver substrate and, hence, form a protective coating on the silver surface. This method is also known as Organic Adsorption Complex Membrane. The adsorption of a 1 ,3,4- thiadiazole having the formula of claim 1 is facilitated via physisorption and chemisorption. Physisorption typically refers to electrostatic interaction between the electron-rich inhibitor molecules (aromatic core structure) and the positively charged silver surface after partial oxidation (surface oxides). On the other hand, chemisorption occurs through coordination bond formation from the present N and S-containing moieties and the conjugated structure of the 1 ,3,4-thiadiazole having the formula of claim 1 .

[0028] Brief Description of the tables

[0029] Objects, features, and advantages of the present invention will also become apparent upon reading the following description in conjunction with the tables, in which:

[0030] Table 1 exhibits the basis detergent formulation used in the examples.

[0031] Table 2 exhibits comparative and inventive beaker test results.

[0032] Table 3 exhibits comparative and inventive Bosch dishwasher test results. Detailed Description of the Invention

[0033] The expression “substantially free” means in the context of the present invention a concentration of less than 0.25 wt%, preferably less than 0.2 wt%, and more preferably less than 0.1 wt%.

[0034] By the term 'corrosion' we hereby include the degradation of the material, as well as the tarnishing and discoloration through the formation of surface compounds, including sulphides, chlorides and oxides of silver.

[0035] In case that Ri and R2 are selected in such a way that tautomerism could take place, the possible respective tautomers shall also be covered by claim 1 of the present invention.

[0036] As used herein, the term "counterion" refers to a monovalent, divalent or trivalent ion. That counterion shall ensure compensation or equalization of the negative charges comprised in said 1 ,3,4-thiadiazole, when at least one moiety R = S' anion with a counterion is comprised in the respective 1 ,3,4-thiadiazole.

[0037] As used herein, the terms "wt%", “%wt.”, “weight %”, and “% by weight” are synonyms to each other. All of these expressions are referring to a weight percentage of the respective component.

[0038] In a preferred embodiment thereof, the composition comprises a 1 ,3,4-thiadiazole having the following formula: wherein

[0039] R1 = Ci - C12 hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3, R4, Rs, and Re = H, Ci - C12 hydrocarbon moiety;

[0040] R2 = Ci - C12 hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3, R4, Rs, and Re = H, Ci - C12 hydrocarbon moiety; and wherein said two moieties R1 and R2 are identical or different.

[0041] In an even more preferred embodiment thereof, the composition comprises a 1 ,3,4-thiadiazole having the following formula: wherein

[0042] R1 = Ci - Ce hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3 and R4 = H, Ci - Ce hydrocarbon moiety; wherein Rs, and Re = H, Ci - C12 hydrocarbon moiety;

[0043] R2 = Ci - Ce hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3 and R4 = H, Ci - Ce hydrocarbon moiety; wherein Rs, and Re = H, Ci - C12 hydrocarbon moiety; and wherein said two moieties R1 and R2 are identical or different.

[0044] In a most preferred embodiment thereof, the composition comprises a 1 ,3,4-thiadiazole having the following formula: wherein

[0045] Ri = Ci - Cs hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3 and R4 = H, Ci - C4 hydrocarbon moiety; wherein Rs, and Re = H, Ce - C12 hydrocarbon moiety;

[0046] R2 = Ci - C3 hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3 and R4 = H, Ci - C4 hydrocarbon moiety; wherein Rs, and Re = H, Ci - C12 hydrocarbon moiety; and wherein said two moieties R1 and R2 are identical or different.

[0047] In one embodiment, the composition comprises 0.01 to 1 wt%, preferably 0.03 to 0.09 wt%, and more preferably 0.06 to 0.8 wt% of said 1 ,3,4-thiadiazole. In one embodiment, the composition is substantially free, preferably completely free, of methyl-1 H-benzotriazole (TTA) and / or 1 H-benzotriazol (BTA).

[0048] The dishwashing, preferably automatic dishwashing, composition of the present invention can comprise a builder.

[0049] The builder may be a phosphate-free builder. In many countries, including the United States and in the European Union, phosphate builders are restricted, or the amount of phosphate permitted in a detergent composition has been severely limited. Therefore, in preferred embodiments, the detergent compositions are substantially phosphate-free.

[0050] The builder comprises one or more small molecule builders selected from hydroxycarboxylates (such as a citrate salt, for example trisodium citrate, which may be anhydrous), aminocarboxylates (such as methyl glycine diacetic acid (MGDA), or N,N-dicarboxymethyl glutamic acid (GLDA)), dicarboxylic acid amines (such as iminodisuccinic acid (IDS)) and / or phosphates (such as tripolyphosphate), or the salts thereof.

[0051] The builder may be present in an amount of greater than 10 %wt., 15 %wt., 20 %wt., 25%wt., 30 wt.%, 35 %wt., 40 %wt., 45 %wt., or greater than 50 %wt. The builder may be present in an amount between 31 and 49 wt.%, between 32 and 41 %wt., or between 33 and 39 %wt.

[0052] The builder may be present in an amount up to 0.1 %wt., 0.2 %wt., 0.3 %wt., 0.4 %wt., 0.5 %wt., 0.6 %wt., 0.7 %wt., 0.8 %wt., 0.9 %wt., 1 %wt., 1.5 %wt., 2 %wt., 3 %wt., 4 %wt., 5 %wt., 6 %wt., 7 %wt., 8 %wt., 9 %wt. or up to 10 %wt.

[0053] The actual amount used in the detergent composition may depend upon the nature of the builder used.

[0054] In one embodiment, the composition further comprises 5 to 45 wt%, preferably 10 to 40 wt%, and more preferably 15 to 35 wt% of a builder; wherein the builder comprises hydroxycarboxylates, preferably a citrate salt, more preferably trisodium citrate; and aminocarboxylates, preferably methyl glycine diacetic acid (MGDA) or N,N-dicarboxymethyl glutamic acid (GLDA).

[0055] In one embodiment, the composition further comprises 5 to 35 wt%, preferably 10 to 25 wt%, and more preferably 15 to 25 wt% of a builder; wherein the builder comprises hydroxycarboxylates, preferably a citrate salt, more preferably trisodium citrate; and wherein the builder is substantially free, preferably completely free, of any aminocarboxylates, preferably methyl glycine diacetic acid (MGDA) or N,N-dicarboxymethyl glutamic acid (GLDA).

[0056] In one embodiment, the composition further comprises 1 to 50 wt%, preferably 3 to 30 wt%, and more preferably 5 to 15 wt% of a phosphonate, preferably etidronic acid (HEDP).

[0057] In one embodiment, the composition further comprises 1 to 15 wt%, preferably 1 .5 to 10 wt%, and more preferably 2 to 5 wt% of an enzyme.

[0058] The dishwashing, preferably automatic dishwashing, composition of the present invention can comprise one or more surfactant(s). Any of non-ionic, anionic, cationic, amphoteric or zwitterionic surface active agents or suitable mixtures thereof may be used. Many such suitable surfactants are described in Kirk Othmer's Encyclopedia of Chemical Technology, 3rd Ed., Vol. 22, pp. 360-379, "Surfactants and Detersive Systems", incorporated by reference herein.

[0059] In the case of automatic dishwashing compositions, it is preferred to minimise the amount of anionic surfactant. Accordingly, preferably the composition comprises no more than 15 %wt., no more than 10 %wt., no more than 5 %wt., no more than 2 %wt, no more than 1 %wt., or no anionic surfactant. Preferably the composition comprises no more than 15 %wt., no more than 10 %wt., no more than 5 %wt., no more than 2 %wt., no more than 1 %wt., or no ionic surfactant of any type. Non-ionic surfactants are preferred for automatic dishwashing products. The non-ionic surfactant may be an optionally end capped alkyl alkoxylate. A preferred class of non-ionic surfactants are ethoxylated non-ionic surfactants prepared by the reaction of a monohydroxy alkanol or alkyl phenol with 6 to 20 carbon atoms. Preferably the surfactants have at least 12 moles per mole of alcohol or alkyl phenol. Particularly preferred non-ionic surfactants are the non-ionics from a linear chain fatty alcohol with 10-20 carbon atoms and at least 5 moles of ethylene oxide per mole of alcohol. The non-ionic surfactant may comprise propylene oxide (PO) units in the molecule. The PO units may constitute up to 40 %wt., 35 %wt., 30 %wt., 25 %wt., 20 %wt. or up to 15 %wt. of the overall molecular weight of the non-ionic surfactant.

[0060] The use of a mixture of any of the aforementioned non-ionic surfactants is suitable in compositions of the present invention.

[0061] In one embodiment, the composition further comprises 0.5 to 50 wt%, preferably 1 to 35 wt%, and more preferably 1 to 20 wt% of a non-ionic surfactant.

[0062] The dishwashing, preferably automatic dishwashing, composition of the present invention can comprise one or more bleaching agents, preferably in combination with one or more bleach activators and / or one or more bleach catalysts. The one or more bleaching agent is preferably selected from the group consisting of an oxygen-releasing bleaching agent, a chlorine-releasing bleaching agent and mixtures thereof.

[0063] The bleaching agent may comprise the active bleach species itself or a precursor to that species. The bleaching agent may be selected from the group consisting of an inorganic peroxide, an organic peracid and mixtures thereof. The terms “inorganic peroxide” and “organic peracid” encompass salts and derivatives thereof. Inorganic peroxides include percarbonates, perborates, persulphates, hydrogen peroxide and derivatives and salts thereof. The sodium and potassium salts of these inorganic peroxides are suitable, especially the sodium salts. Sodium percarbonate is particularly preferred. The active bleaching agent is preferably present in an amount from 5 to 50%wt., from 7 to 35%wt., from 9 to 25%wt., or from 1 1 to 20%wt.

[0064] The composition may further comprise one or more bleach activators and / or bleach catalysts. Any suitable bleach activator may be included, for example Tetraacetylethylenediamine (TAED), if this is desired for the activation of the bleaching agent. Any suitable bleach catalyst may be used, for example manganese acetate or dinuclear manganese complexes such as those described in EP 1741774 A1 , the contents of which are incorporated herein by reference. The organic peracids such as perbenzoic acid and peroxycarboxylic acids e.g. phthalimidoperoxyhexanoic acid (PAP) do not require the use of a bleach activator or catalyst as these bleaches are active at relatively low temperatures such as 30°C.

[0065] The bleach catalyst may be a manganese complex comprising 1 ,4,7- Triazacyclononane (TACN), or any derivatives of a TACN ligand, for example 1 ,4,7-trimethyl-TACN, manganese oxalate, manganese acetate or a dinuclear manganese complex, for example a dinuclear manganese complex comprising TACN or any derivatives of a TACN ligand, for example 1 ,4,7-trimethyl-TACN

[0066] In one embodiment, the composition further comprises 5 to 40 wt%, preferably 7 to 30 wt%, and more preferably 10 to 25 wt% of an oxygen based bleaching system.

[0067] In a preferred embodiment thereof, said oxygen based bleaching system comprises at least a bleaching catalyst, a bleaching activator, and an oxygen based bleaching agent.

[0068] In one embodiment, the composition is a dishwashing, preferably an automatic dishwashing, detergent composition or a rinse aid composition.

[0069] In one embodiment, the composition is wrapped into at least one water- soluble film comprising polyvinyl alcohol (PVOH), preferably being a PVOH foil; wherein preferably such a water-soluble film has a thickness ranging from 50 to 150 micrometers; and wherein in particular 300 to 600 mg of such a water-soluble film material is required for a monodose ADW product.

[0070] In a preferred embodiment, a “hydrocarbon moiety” means an alkyl group.

[0071] Further, the object of the present invention is also solved by the use of such an inventive dishwashing, preferably an automatic dishwashing, composition for silver corrosion protection of silver dishwashing goods; wherein preferably said dishwashing, preferably said automatic dishwashing, composition is a detergent composition or a rinse aid composition.

[0072] The present invention thus addresses the problem of providing a dishwashing composition comprising a specific silver corrosion inhibition agent, which ensures a silver corrosion protection being at least comparable to the commonly used dishwashing compositions comprising benzotriazoles or derivatives thereof.

[0073] The following non-limiting examples are provided to illustrate an embodiment of the present invention and to facilitate understanding of the invention but are not intended to limit the scope of the invention, which is defined by the claims.

[0074] Experimental Part:

[0075] The following 1 ,3,4-thiadiazoles have been used for the inventive examples:

[0076] 1 ,3,4-Thiadiazole-2,5-dithiol (CAS 1072-71-5)

[0077] 2-(nonyldisulfanyl)-1 ,3,4-thiadiazole

[0078] 2,5-Bis(nonyldisulfanyl)-1 ,3,4-thiadiazole ,5-bis(2-methylundecan-2-yldisulfanyl)-1 ,3,4-thiadiazole (CAS 59656- 20-1) 5-(Methylthio)-1 , 3,4-thiad iazole-2-thiol (CAS 6264-40-0)

[0079] 5-Methyl-1 ,3,4-thiadiazole-2-thiol (CAS 29490-19-5)

[0080] 1 ,3,4-Thiadiazole-2-amine (CAS 4005-51-0)

[0081] 5-Methyl-1 ,3,4-thiadiazole-2-amine (CAS 108-33-8)

[0082] 1 ,3,4-Thiadiazole-2,5-dithiol dipotassium salt (CAS 4628-94-8) The following basis formulation has been used for the comparative and inventive experiments of the present invention:

[0083] Table 1 : Basis detergent formulation used in the examples.

[0084] Test method - Beaker test The silver protection performance is assessed following “Beaker” screening test method:

[0085] • Basis detergent formulation dissolved in beaker on a 3L water having 21 °dH water hardness, no soil added.

[0086] • Stirred and heated up to 50°C. • 10mg, 50mg, or 10Omg of the respective 1 ,3,4-thiadiazole is added to the solution for inventive examples of the present invention. In case of comparative examples, no additional component or an additional component outside of the scope of claim 1 is added to the basis formulation.

[0087] • The bowl of the silver spoons (Silver-plated stainless steel from WMF (“Flair” spoon) and silver-coated silver items from Wilkens (“Palladio” spoon)) were put into the beaker.

[0088] • Beakers with test solutions and silver spoons were put in the heat cabinet at 50°C for approx. 12h.

[0089] • After this procedure each bowl of the spoons were visually assessed using for evaluation the following scale below:

[0090] Evaluation scale:

[0091] 5 - No surface modifications I discoloration

[0092] 4 - Minor surface modifications I discoloration, hardly visible

[0093] 3 - Visible surface modifications I discoloration 2 - Strong surface modifications / discoloration

[0094] 1 - Very strong surface modifications / discoloration, clearly visible

[0095] Results Beaker Test:

[0096] Table 2: Comparative and inventive beaker test results.

[0097] 5 mg of the respective additional component represents 0.036 wt%.

[0098] 10 mg of the respective additional component represents 0.071 wt%.

[0099] 20 mg of the respective additional component represents 0.14 wt%. 50 mg of the respective additional component represents 0.355 wt%.

[0100] 100 mg of the respective additional component represents 0.71 wt%.

[0101] Conclusion:

[0102] Surprisingly, it was found that

[0103] (i) all 1 ,3,4-thiadiazole components according to the present invention provide a good silver protection (less tarnishing) on tested silver spoons compared to the comparative examples 1 and 2; and that

[0104] (ii) adding only 10 mg of inventive components are already well performing, silver looks like fresh, not treated spoons.

[0105] Test method - Dishwasher test

[0106] • The test is conducted under EU relevant conditions, i.e., Bosch DW model SMS466MW03E / 41 using program Eco + Vario speed, at 21 °GH, no soil added. • The automatic dishwasher was charged with silver spoons (Silver-plated stainless steel from WMF (“Flair” spoon) and silver-coated silver items from Wilkens (“Palladio” spoon)).

[0107] • Base detergent formulation without (comparative example) or with an added inventive 1 ,3,4-thiadiazole (inventive example) is dosed in the main wash cycle.

[0108] • The silverware items were assessed after 10 dishwashing (DW) cycles.

[0109] • After this procedure each bowl of the spoons were visually assessed using for evaluation the same scale as given above already for the Beaker tests. Results Bosch DW Test:

[0110] Table 3: Comparative and inventive Bosch dishwasher test results. Conclusion:

[0111] (i) Results in Bosch DW correlates quite good with beaker test results, confirming the results that even very low amounts of an added 1 ,3,4-thiadia- zole component according to the present invention provide visible silver care compared to a base detergent formulation without an added inventive 1 ,3,4-thiadiazole.

[0112] (ii) Even adding 5mg (= 0,036%) of 2,5-bis(2-methylundecan-2-yldisulfanyl)- 1 ,3,4-thiadiazole is already performing positive on silver care (inventive example 3). Doubling this amount to 10 mg (= 0,071 %) (inventive DW example 2) is boosting as expected the level of silver protection.

[0113] (iii) Surprisingly when adding 20 mg (= 0,14%) (inventive example 1 and inventive example 4) is not boosting anymore level of silver protection. In contrast, protection level is getting lower, which is totally unexpected.

[0114] While the principles of the invention have been explained in relation to certain particular embodiments, and are provided for purposes of illustration, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims. The scope of the invention is limited only by the scope of the appended claims.

Claims

C L A I M S1. A dishwashing, preferably an automatic dishwashing, composition, characterized in that the composition comprises a 1 ,3,4-thiadiazole having the following formula:whereinRi = Ci - C hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3, R4, Rs, and Re = H, Ci - Cis hydrocarbon moiety;R2 = Ci - C hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3, R4, Rs, and Re = H, Ci - C18 hydrocarbon moiety; and wherein said two moieties R1 and R2 are identical or different.

2. Dishwashing, preferably an automatic dishwashing, composition according to claim 1 characterized in that the composition comprises a 1 ,3,4-thiadiazole having the following formula:whereinR1 = Ci - C12 hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3, R4, Rs, and Re = H, Ci - C12 hydrocarbon moiety;R2 = Ci - C12 hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3, R4, Rs, and Re = H, Ci - C12 hydrocarbon moiety; and wherein said two moieties R1 and R2 are identical or different.

3. Dishwashing, preferably an automatic dishwashing, composition according to claim 1 or 2 characterized in that the composition comprises a 1 ,3,4-thiadiazole having the following formula:whereinR1 = Ci - Ce hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3 and R4 = H, Ci - Ce hydrocarbon moiety; wherein Rs, and Re = H, Ci - C12 hydrocarbon moiety;R2 = Ci - Ce hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3 and R4 = H, Ci - Ce hydrocarbon moiety; wherein Rs, and Re = H, Ci - C12 hydrocarbon moiety; and wherein said two moieties R1 and R2 are identical or different.

4. Dishwashing, preferably an automatic dishwashing, composition according to one of the preceding claims characterized in that the composition comprises a 1 ,3,4-thiadiazole having the following formula:whereinR1 = Ci - C3 hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3 and R4 = H, Ci - C4 hydrocarbon moiety; wherein Rs, and Re = H, Ce - C12 hydrocarbon moiety;R2 = Ci - C3 hydrocarbon moiety, NR3R4 moiety, S-Rs moiety, S-S-Re moiety, H, S' anion with a counterion; wherein R3, R4, Rs, and Re can be identical or different; wherein R3 and R4 = H, Ci - C4 hydrocarbon moiety;wherein Rs, and Re = H, Ci - C12 hydrocarbon moiety; and wherein said two moieties R1 and R2 are identical or different.

5. Dishwashing, preferably an automatic dishwashing, composition according to one of the preceding claims characterized in that the composition comprises 0.01 to 1 wt%, preferably 0.03 to 0.09 wt%, and more preferably 0.06 to 0.8 wt% of said 1 ,3,4-thiadiazole.

6. Dishwashing, preferably an automatic dishwashing, composition according to one of the preceding claims characterized in that the composition is substantially free, preferably completely free, of methyl-1 H- benzotriazole (TTA) and / or 1 H-benzotriazol (BTA).

7. Dishwashing, preferably an automatic dishwashing, composition according to one of the preceding claims characterized in that the composition further comprises 5 to 45 wt%, preferably 10 to 40 wt%, and more preferably 15 to 35 wt% of a builder; wherein the builder comprises hydroxycarboxylates, preferably a citrate salt, more preferably trisodium citrate; and aminocarboxylates, preferably methyl glycine diacetic acid (MGDA) or N,N-dicarboxymethyl glutamic acid (GLDA).

8. Dishwashing, preferably an automatic dishwashing, composition according to one of the preceding claims characterized in that the composition further comprises 5 to 35 wt%, preferably 10 to 25 wt%, and more preferably 15 to 25 wt% of a builder; wherein the builder comprises hydroxycarboxylates, preferably a citrate salt, more preferably trisodium citrate; and wherein the builder is substantially free, preferably completely free, of any aminocarboxylates, preferably methyl glycine diacetic acid (MGDA) or N,N-dicarboxymethyl glutamic acid (GLDA).

9. Dishwashing, preferably an automatic dishwashing, composition according to one of the preceding claims characterized in that the composition further comprises 1 to 50 wt%, preferably 3 to 30 wt%, and more preferably 5 to 15 wt% of a phosphonate, preferably etidronic acid (HEDP).

10. Dishwashing, preferably an automatic dishwashing, composition according to one of the preceding claims characterized in that the composition further comprises 1 to 15 wt%, preferably 1.5 to 10 wt%, and more preferably 2 to 5 wt% of an enzyme.

11. Dishwashing, preferably an automatic dishwashing, composition according to one of the preceding claims characterized in that the composition further comprises 0.5 to 50 wt%, preferably 1 to 35 wt%, and more preferably 1 to 20 wt% of a non-ionic surfactant.

12. Dishwashing, preferably an automatic dishwashing, composition according to one of the preceding claims characterized in that the composition further comprises 5 to 40 wt%, preferably 7 to 30 wt%, and more preferably 10 to 25 wt% of an oxygen based bleaching system.

13. Dishwashing, preferably an automatic dishwashing, composition according to claim 12 characterized in that said oxygen based bleaching system comprises at least a bleaching catalyst, a bleaching activator, and an oxygen based bleaching agent.

14. Dishwashing, preferably an automatic dishwashing, composition according to one of the preceding claims characterized in that the composition is a dishwashing, preferably an automatic dishwashing, detergent composition or a rinse aid composition.

15. Use of a dishwashing, preferably an automatic dishwashing, composition according to one of the preceding claims for silver corrosion protection of silver dishwashing goods; wherein preferably said dishwashing, preferably said automatic dishwashing, composition is a detergent composition or a rinse aid composition.

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