EP4396318A1

EP4396318A1 - Machine dishwash detergent

Info

Publication number: EP4396318A1
Application number: EP22768765.4A
Authority: EP
Inventors: Katherine Mary Thompson
Original assignee: Unilever Global IP Ltd; Unilever IP Holdings BV
Current assignee: Unilever Global IP Ltd; Unilever IP Holdings BV
Priority date: 2021-09-01
Filing date: 2022-08-23
Publication date: 2024-07-10
Also published as: EP4396317A1; WO2023030882A1; WO2023031119A1; EP4396319A1; WO2023030965A1

Abstract

A machine dishwash detergent composition comprising from 0.1 to 20 wt. % non-ionic surfactant; and bleach; and from 0.005 to 20 wt. % of acid derivative of pyridine comprising one or more coordinate covalent bound iron- (Fe), Manganese- (Mn) and/or cobalt- (Co) cations; and wherein the composition comprises at most 1 wt. % of phosphate.

Description

MACHINE DISHWASH DETERGENT

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a machine dishwash detergent composition comprising an acid derivative of pyridine comprising one or more coordinate covalent bound iron-, cobalt- and/or manganese-cations.

BACKGROUND OF THE INVENTION

Machine dishwash detergent compositions typically contain several different active components, including builders, surfactants, enzymes and bleaching agents. Surfactants are employed to remove stains and soil and to disperse the released components into the cleaning liquid. Enzymes help to remove stubborn stains of proteins, starch and lipids by hydrolyzing these components. Bleach is used to remove stains by oxidizing the components that make up these stains. To reduce the negative effects of calcium and magnesium ions on stain/soil removal so called 'builders' (complexing agents) are commonly applied in detergent compositions.

Phosphate based builders have been used for many years in machine dishwash detergent compositions, such as trisodium phosphate and sodium tripolyphosphate (STPP). Although having excellent performance in dishwasher detergents their presence in the wastewater can lead to environmental problems such as eutrophication. As such there has been a need for more environmentally friendly alternative builders with on-par effectiveness. Examples of such alternative builders are aminopolycarboxylates, such as glutamic acid N,N-diacetic acid (GLDA), methylglycinediacetic acid (MGDA) and are ethylenediaminetetraacetic acid (EDTA).

Phosphonates are known chelators. A downside of phosphonates is their poor biodegradability and that they too contain phosphorous with associated eutrophicationrisk of the environment. An example of a widely used phosphonate in machine dishwash detergents is HEDP (1-hydroxyethylidene-1,1-disphosphonic acid).

Current machine dishwash compositions typically contain a bleach system to tackle difficult to remove colored stains, such as tea-stains. Bleach systems, beside a source of bleach, typically contain bleach activator and bleach catalyst to provide effective bleaching also at low wash temperatures. One known effective bleach catalyst is based on a manganese complex of the formula [L_nMn_mXp]^zYq, as described in EP0458397A2. Such bleach catalysts have fallen in disfavor as they have poor biodegradability and tend to persist in the environment.

There is a constant desire to make machine dishwash detergents more environmentally friendly and for machine dishwash detergent compositions to be more fully biodegradable. A prime requisite for consumer acceptance however is that more fully biodegradable detergents still need to perform well in cleaning dishware.

It is an object of the present invention to provide a machine dishwash detergent composition which has effective bleaching activity with improved biodegradability and furthermore to provide such a composition while using commonly known ingredients in machine dishwashing and while keeping the ingredient list as short as possible for effective cleaning, in particular for effective tea-stain cleaning.

SUMMARY OF THE INVENTION

One or more objects of the invention have been achieved by a machine dishwash detergent composition comprising:

• from 0.1 to 20 wt. % non-ionic surfactant; and

• bleach; and

• from 0.005 to 20 wt. % of acid derivative of pyridine comprising one or more coordinate covalent bound iron- (Fe), Manganese- (Mn) and/or cobalt- (Co) cations; and; wherein the composition comprises at most 1 wt. % of phosphate; wherein the pH of a solution of 1 wt.% of the detergent composition in water as measured at 25 degrees Celsius is from 6.0 to 10.8.

Unless otherwise made clear from the context, where the terms ‘aminopolycarboxylic acid’ or ‘organic acid’ are used these encompass their corresponding salts (and vice versa). Surprisingly it was observed that acid derivative of pyridine comprising one or more coordinate covalent bound iron- (Fe), Manganese- (Mn) and/or cobalt- (Co) cations can be effective in promoting bleaching of stains by having bleach catalyst activity. This is quite relevant since acid derivatives of pyridine tend to be readily biodegradable and since many are naturally occurring and can be bio-sourced. Prime examples of such non-aromatic organic acid sequestrants are picolinic acid and dipicolinic acid.

Therefore, in another aspect the invention relates to the use of acid derivative of pyridine comprising one or more coordinate covalent bound iron- (Fe), Manganese- (Mn) and/or cobalt- (Co) cations to provide a machine dishwash detergent composition with a bleach system having improved biodegradability and/or reduced fossil carbon footprint.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

Weight percentage (wt.%) is based on the total weight of the detergent composition unless otherwise indicated or as made clear from the context. It will be appreciated that the total weight amount of ingredients will not exceed 100 wt. %. Whenever an amount or concentration of a component is quantified herein, unless indicated otherwise, the quantified amount or quantified concentration relates to said component per se, even though it may be common practice to add such a component in the form of a solution or of a blend with one or more other ingredients. It is furthermore to be understood that the verb "to comprise" and its conjugations is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. Finally, reference to an element by the indefinite article "a" or "an" does not exclude the possibility that more than one of the elements is present, unless the context clearly requires that there be one and only one of the elements. The indefinite article "a" or "an" thus usually means "at least one". Unless otherwise specified all measurements are taken at standard conditions. Whenever a parameter, such as a concentration or a ratio, is said to be less than a certain upper limit it should be understood that in the absence of a specified lower limit the lower limit for said parameter is 0. Concentrations expressed in wt. % of ‘free acid equivalent’ refer to the concentration of the compound expressed as wt. %, assuming it would be in fully protonated from. The following table shows how the free acid equivalent concentrations can be calculated for some (anhydrous) aminopolycarboxylates and (anhydrous) acid salts.

Non-ionic surfactants

Suitable non-ionic surfactants which may be used include preferably the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide.

Preferably low-foaming nonionic surfactants are used particularly from the group of alkoxylated alcohols. Alkoxylated, advantageously ethoxylated, in particular primary alcohols with preferably 8 to 18 C atoms and on average 1 to 12 mol of ethylene oxide (EO) per mol of alcohol, in which the alcohol residue may be linear or preferably methyl-branched in position 2 or may contain linear and methyl-branched residues in the mixture, as are usually present in oxo alcohol residues, are preferably used as nonionic surfactants. In particular, however, alcohol ethoxylates with linear residues prepared from alcohols of natural origin with 12 to 18 C atoms, for example from coconut, palm, tallow fat or oleyl alcohol, and on average 2 to 8 mol of EO per mol of alcohol are preferred. The preferred ethoxylated alcohols include for example C12-14 alcohols with 3 EO to 4 EO, C9-12 alcohol with 7 EO, C13-15 alcohols with 3 EO, 5 EO, 7 EO or 8 EO, C12-18 alcohols with 3 EO, 5 EO or 7 EO and mixtures of these, such as mixtures of C12-14 alcohol with 3 EO and C12-19 alcohol with 5 EO. Preferred tallow fatty alcohols with more than 12 EO have from 60 to 100 EO, and more preferably from 70 to 90 EO. Particularly preferred tallow fatty alcohols with more than 12 EO are tallow fatty alcohols with 80 EO.

Nonionic surfactants from the group of alkoxylated alcohols, particularly preferably from the group of mixed alkoxylated alcohols and in particular from the group of EO-AO-EO nonionic surfactants, are likewise particularly preferentially used. Preferably used nonionic surfactants originate from the groups comprising alkoxylated nonionic surfactants, in particular ethoxylated primary alcohols and mixtures of these surfactants with structurally complex surfactants such as polyoxypropylene/ polyoxyethylene/ polyoxypropylene (PO/EO/PO). Such (PO/EO/PO) nonionic surfactants are furthermore distinguished by good foam control.

The most preferred nonionic surfactants are according to the formula: wherein n is from 0 to 5 and m from 10 to 50, more preferably wherein n is from 0 to 3 and m is from 15 to 40, and even more preferably wherein n is 0 and m is from 18 to 25. Surfactants according to this formula were particularly useful in reducing spotting of dishware treated in a machine dish washer. Preferably at least 50 wt. % of the nonionic surfactant comprised by the detergent composition of the invention is nonionic surfactant according to this formula. Such nonionic surfactants are commercially available, for example under the tradename Dehypon WET (Supplier: BASF) and Genapol EC50 (Supplier Clariant). The detergent composition of the invention comprises from 0.1 to 20 wt. % of a nonionic surfactant or a mixture of two or more nonionic surfactants. The preferred amount of total non-ionic surfactant if from 1 to 18 wt. %, more preferably from 4 to 16 wt. % and even more preferably from 6 to 12 wt.%. Such levels are considered optimal. The nonionic surfactant is preferably present in amounts of 25 to 90 wt. % based on the total weight of the surfactant system. Anionic surfactants can be present for example in amounts in the range from 5 to 40 wt. % of the surfactant system.

Acid derivatives of pyridine with coordinate covalent bound Fe, Mn and/or Co cations Pyridine is a heterocyclic organic compound with the chemical formula C5H5N. Acid derivatives of pyridine acid derivatives are defined as pyridine compounds in which at least one or more of the H-atoms is replaced with and acid moiety, such as carboxylic acid moiety and/or a sulfonic acid moiety.

Preferred are carboxylic acid moieties and especially those based on formic acid (i.e. - COOH), acetic acid (i.e. CH2COOH), propionic acid (e.g. -CH2CH2COOH), of these those based on formic acid are even more preferred. Examples of such acid derivatives of pyridine with one or more carboxylic acid moieties based on formic acid are picolinic acid and dipicolinic acid.

At least one of the hydrogen atoms of the pyridine is replaced with an acid moiety. A such 1, 2, 3, 4 or all of the hydrogen atoms of a pyridine can be replaced with an acid moiety. Best results were found when at least 2 of the hydrogen atoms were replaced with an acid moiety. Hence advantageously 2 or 3 hydrogen atoms are replaced with an acid moiety and more beneficially 2 are replaced with an acid moiety. Preferentially, the pyridine ring is substituted with at least one (carboxylic) acid moiety at the 2- or 3- positions, more preferably at the 2-position.

Apart from replacement of at least one hydrogen atoms of a pyridine with an acid moiety, the acid derivatives of pyridine can include those compounds in which further hydrogen atoms are replaced by non-acid moieties. Examples are acid derivatives of pyridine which can be considered acid derivatives of bromo-pyridine and bipyridine. However preferably the acid derivative of pyridine invention is based on the chemical formula C5H5N in which one or more H-atoms are replaced acid moieties only.

A coordinate covalent bond, also known as a dative bond, dipolar bond, or coordinate bond is a type of two-centre, two-electron covalent bond in which the two electrons derive from the same atom. The bonding of metal ions to ligands generally involves this type of bond.

The preferred complexes have the following formulae: [M_mL_n]^pY^q.rH2O where, M is iron, manganese or cobalt, L is an acid derivative of pyridine ligand, m = 1-3, n = 1-3, p = 0- 3, q = 0-3, r = 0-3. If p <1 >, Y is counterion.

General methods to prepare organic ligand-metal ion complexes are known in the art (e.g. V. Springer et. al. Preparation and study of the solid complexes of the racemic ethylenediamine-N,N'-disuccinic acid with iron(lll), cobalt(lll), and bismuth(lll) ions.

Chem. Zvesti 34(2), pages 184-189, 1980; US5,559,261).

The preferred method of manufacture the acid derivative of pyridine comprising one or more coordinate covalent bound iron- (Fe), Manganese- (Mn) and/or cobalt- (Co) cations comprises the following steps: a) providing an aqueous solution comprising acid derivative of pyridine and Fe, Mn and/or Co cations, wherein the molar ratio of the acid derivative of pyridine and the cations is from 100:1 to 1 :6; and b) optionally adjusting the pH of the aqueous solution to the range of from 6 to 11 ; and c) removing water from the aqueous solution to provide a composition comprising acid derivative of pyridine comprising coordinate covalent bound Fe, Mn and/or Co cations and the composition having water content of at most 60 wt.% and/or precipitating the complexes from aqueous solution by adding a non-aqueous solvent (preferably an organic solvent such as ethanol).

Preferably at step c) water is removed until a solid is provided or a precipitated solid formed on addition of an organic solvent is separated from the supernatant solution by filtration and then air dried. This is especially advantageous when the acid derivative of pyridine comprising one or more coordinate covalent bound iron- (Fe), Manganese- (Mn) and/or cobalt- (Co) cations is part of the ingredients to make a tablet or powder detergent.

Suitable examples of such water-soluble salts are the chloride, sulphate or carbonate salts of Fe, Mn and/or Co. The Fe²⁺, Fe³⁺, Mn²⁺, Mn³⁺, Mn⁴⁺, Mn⁵⁺, Mn⁶⁺, Mn⁷⁺ and Co²⁺, Co³⁺ are the preferred cations. Advantageously the cation is a Fe²⁺, Fe³⁺, Mn²⁺ and/or Mn⁴⁺ cation and particularly preferred are the Fe³⁺, Fe²⁺ and Mn²⁺ oxidation states.

As indicated in the method, the molar ratio of acid derivative of pyridine and the cations can be from 100:1 to 1 :6. Lower ratios will lead to only a part of the acid derivative of pyridine comprising coordinate covalent bound Fe, Mn and/or Co ions. This can be beneficial since such an acid derivative of pyridine mixture can both contribute to effective bleaching as well aiding builder and chelating functionality in one go. Higher ratios are beneficial to provide a more targeted bleach catalyst activity and can allow for more than one Fe, Mn and/or Co cation to be coordinate covalent bound to the acid derivative of pyridine. In this respect it is noted that some acid derivative of pyridine can be capable of coordinate covalent binding more than one Fe, Mn and/or Co cations.

Preferred compounds include [Fe^IH(pic)3], [Fe(pic)2(H2O)]‘, [Fe^IN(pic)2OH]2, [Fe"^l ₂(OH)₂(pic)₄], [Mn"(pic)(OH)₂]_n, [Mn"CI(pic)(H₂O)₂]n, [Mn" (pic)₂]„, [Mn"CI(pic)]„, [Mn"(pic)₂ (H₂O)2], [Mn"(pic)₂ (OH)₂]²‘, [Mn" Cl₂(pic)₂]²-, [Mn^l"(pic)₃], [Mn^l"(pic)₂(OH)], [Mn"^lCI(pic)₂(H₂O)], [Mn^lv ₂O₂(pic)₄], [Co" (pic)₂], [Co'"(pic)3], [Fe"(dipic)(H₂O)₃], [Fe"(dipic)₂]²-, [Fe"₂(dipic)2(H₂O)6], [Fe^IH(dipic)(OH)], [Fe^l"(dipic)₂]-, [Mn"(dipic)(H₂O)₃], [Mn"(dipic)2(H₂O)]²', [Mn"2(dipic)2(H₂O)6], [Mn^l"(dpic)₂]’, [Co"(dipic)₂]', [Co^IH(dipic)2] where Hpic is picolinic acid and Adipic is dipicolinic acid. The ‘n’ subscript may take values of more than 1 and indicates such compounds may exhibit polymerization.

The machine dishwash detergent composition comprises from 0.005 to 20 wt. % of acid derivative of pyridine comprising one or more coordinate covalent bound Fe, Mn and/or Co cations. A further beneficial amount is from 0.01 to 20 wt.%, more preferably from 0.015 to 20 wt. %, even more preferably from 0.05 to 20 wt. %, still even more preferably from 0.1 to 20 wt. %, still even more preferably from 0.2 to 10 wt. %, still even more preferably from 0.3 to 5 wt. % and still even more preferably from 0.4 to 4 wt. %

Besides the acid derivative of pyridine non-covalently bound to one or more Fe, Mn and/or Co cations, further organic acid may be present which does not comprise such coordinate covalent bound Fe, Mn and/or Co cations.

An optimal balance of acid derivative of pyridine comprising one or more coordinate covalent bound Fe, Mn or Co cations versus non-aromatic organic acid not comprising such, is considered to be from 1:4000 to 100:1 , more preferably from 1:100 to 20:1, even more preferably from 1 :50 to 1 :1 and still even more preferably from 1 :20 to 1 :10. Such ratios provide a balanced bleach catalyst activity and a sequestrant activity.

Preferably the detergent composition of the invention does not comprise further poorly biodegradable bleach catalyst and beneficially comprises essentially no further bleach catalyst (biodegradable or not).

In particular it is preferred that the acid derivative of pyridine has an average molecular mass of at most 500 Dalton, more preferably of at most 400 Dalton and most preferably of at most 300 Dalton, the molecular mass being based on the free acid equivalent. In any case, preferably the acid derivative of pyridine is not a polymer-based acid as these tend to be less biodegradable. The acid derivative of pyridine employed in accordance with the invention preferably comprises 6 to 25 carbon atoms, more preferably 7 to 10 carbon atoms.

The acid derivative of pyridine of the invention preferably does not contain any covalently bound P atoms to reduce any eutrophication issues. Further preferred is that it does not contain any S atoms. In fact, the most preferred acid derivative of pyridine of the invention contains no other covalently bound atoms than C, H, O and N atoms.

Organic Acid

Inclusion of further organic acids and/or their corresponding salts (not comprising coordinate covalent bonds with Fe, Mn and/or Co cation and not being aminopolycarboxylates) is beneficial in providing improved detergency whilst capable of being made from renewable materials (e.g. plant-based) and readily biodegradable.

Said further organic acid used in the detergent composition of the invention can be any organic acid. Particularly good results were achieved with organic acids being polyacids (i.e. acids having more than one carboxylic acid group), and more particularly with di- or tricarboxylic organic acids. The organic acids used in the invention have an average molecular mass of at most 500 Dalton, more preferably of at most 400 Dalton and most preferably of at most 300 Dalton, the molecular mass being based on the free acid equivalent. In any case, preferably the organic acid is not a polymer-based acid. The organic acid employed in accordance with the invention preferably comprises 3 to 25 carbon atoms, more preferably 4 to 15 carbon atoms.

In view of consumer acceptance and reducing environmental impact, the organic acids preferably are those which are also found naturally occurring, such as in plants. As such, organic acids of note are acetic acid, citric acid, aspartic acid, lactic acid, adipic acid, succinic acid, glutaric acid, malic acid, tartaric acid, maleic acid, fumaric acid, saccharic acids, their salts, or mixtures thereof. Of these, of particular interest are citric acid, aspartic acid, acetic acid, lactic acid, succinic acid, glutaric acid, adipic acid, gluconic acid, their salts, or mixtures thereof. Citric acid was found highly advantageous. Citric acid is naturally occurring, highly biodegradable as well as providing added builder activity and disintegration properties.

Advantageously the detergent composition of the invention comprises a free acid equivalent of organic of from 1 to 30 wt. %, more preferably of from 5 to 20 wt. % and even more preferably from 8.0 to 15 wt.%. Preferred salt forms of the further organic acid are alkali metal salts and beneficially their sodium salts.

Aminopolycarboxylate

Aminopolycarboxylates are well known in the detergent industry and sometimes referred to as aminopolycarboxylic acids chelants. They are generally appreciated as being strong builders. Suitable aminopolycarboxylic acids include glutamic acid N,N- diacetic acid (GLDA), methylglycinediacetic acid (MGDA), ethylenediaminedisuccinic acid (EDDS), iminodisuccinic acid (IDS), iminodimalic acid (IDM), ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), diethylenetriaminepentaacetic acid (DTPA), hydroxyethyliminodiacetic acid (HEIDA) aspartic acid diethoxysuccinic acid (AES) aspartic acid-N,N-diacetic acid (ASDA) , hydroxyethylene-diaminetetraacetic acid (HEDTA), hydroxyethylethylenediaminetriacetic acid (HEEDTA) , iminodifumaric (IDF), iminoditartaric acid (IDT), iminodimaleic acid (IDMAL), ethylenediaminedifumaric acid (EDDF), ethylenediaminedimalic acid (EDDM), ethylenediamineditartaric acid (EDDT), ethylenediaminedimaleic acid and (EDDMAL).

Preferred aminopolycarboxylates are GLDA, MGDA, EDDS, IDS, IDM or a mixture thereof, more preferred are GLDA, MGDA, EDDS or a mixture thereof and even more preferred are GLDA and MGDA or a mixture thereof. Of these GLDA is especially preferred as it can be made from bio-based materials (e.g. monosodium glutamate, which itself can be made as by-product from corn fermentation). Also, GLDA itself is highly biodegradable. MGDA is more preferred in view of it being somewhat less hygroscopic, which improves detergent stability during storage.

The detergent composition according to the invention preferably comprises from 0.5 to 40 wt. % free acid equivalent of total aminopolycarboxylate. A particularly preferred amount of free acid equivalent of aminopolycarboxylate is from 0.5 to 20 wt. %, more preferably from 1.0 to 15 wt. %, even more preferably from 2.0 to 10 wt. % and still even more preferably from 3.0 to 8 wt.%.

Preferred salts are alkali-based salts and more preferred are sodium-based salts. pH profile

The detergent composition of the invention preferably provides a pH of a solution of 1 wt.% of the detergent composition in water as measured at 25 degrees Celsius of from 6.0 to 10.8, more preferably from 6.5 to 10.6, even more preferably 7.0 to 10.5, still even more preferably from 7.5 to 10.2, still even more preferably from 8.5 to 10.0 and still even more preferably from 9.0 to 10.0. Bleach

The detergent composition of the invention preferably comprises from 0.1 to 25 wt. % of bleach. Inorganic and/or organic bleaches can be used. Bleach may be selected from peroxides, organic peracids, salts of organic peracids and combinations thereof. Advantageously the bleach is selected from peroxides (including peroxide salts such as sodium percarbonate), organic peracids, salts of organic peracids and combinations thereof. More preferably, the bleach is a peroxide. Most preferably, the bleach is a percarbonate. Further preferred, the bleach is a coated percarbonate. More preferred amounts of bleach are from 1.0 to 25 wt.%, even more preferably at from 2.0 to 20 wt. % and still even more preferably from 5 to 15 wt.%.

Further ingredients

The detergent composition of the invention may comprise further ingredients, such as further detergent active components.

Bleach Activators

The detergent composition of the invention preferably comprises one or more bleach activators such as peroxyacid bleach precursors. Peroxyacid bleach precursors are well known in the art. As non-limiting examples can be named N, N, N', N '-tetraacetyl ethylene diamine (TAED), sodium nonanoyloxybenzene sulphonate (SNOBS), sodium benzoyloxybenzene sul phonate (SBOBS) and the cationic peroxyacid precursor (SPCC) as described in US-A-4, 751 ,015. A beneficial amount of bleach activator is from 0.1 to 10 wt.%, more preferably from 0.5 to 5 wt.% and even more preferably from 1 .0 to 4 wt. %.

Further builders

Further builder materials may be selected from 1) calcium sequestrant materials, 2) precipitating materials, 3) calcium ion-exchange materials and 4) mixtures thereof.

Examples of calcium ion-exchange builder materials include the various types of waterinsoluble crystalline or amorphous aluminosilicates, of which zeolites are known representatives, e.g. zeolite A, zeolite B (also known as zeolite P), zeolite C, zeolite X, zeolite Y and also the zeolite P-type as described in EP-A-0,384,070. Zeolite and carbonate (carbonate (including bicarbonate and sesquicarbonate) are preferred further builders. The builder may be crystalline aluminosilicate, preferably an alkali metal aluminosilicate, more preferably a sodium aluminosilicate. This is typically present at a level of less than 15 wt. %. Aluminosilicates are materials having the general formula: 0.8-1 .5 M2O. AI2O3. 0.8-6 SiC>2, where M is a monovalent cation, preferably sodium. These materials contain some bound water and are required to have a calcium ion exchange capacity of at least 50 mg CaO/g. The preferred sodium aluminosilicates contain 1.5-3.5 SiC>2 units in the formula above. They can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature. The ratio of surfactants to alumuminosilicate (where present) is preferably greater than 5:2, more preferably greater than 3:1.

Alkali carbonate is appreciated in view of its double function as builder and buffer and is preferably present in the detergent composition. The preferred amount of alkali carbonate in the detergent composition is from 2 to 75 wt.%, more preferably from 10 to 50 wt.% and even more preferably from 20 to 40 wt.%. Such level of alkali carbonate provides good Ca²⁺ and Mg²⁺ ion scavenging for most types of water hardness levels, as well as other builder effects, such as providing good buffering capacity. The preferred alkali carbonates are sodium- and/or potassium carbonate of which sodium carbonate is particularly preferred. The alkali carbonate present in the detergent composition of the invention can be present as such or as part of a more complex ingredient (e.g. sodium carbonate in sodium percarbonate).

The detergent composition is phosphate-free, i.e., contains at most 1.0 wt. %, preferably at most 0.8 wt.%, more preferably at most 0.5 wt. %, even more preferably at most 0.2 wt.% of phosphate and still even more preferably contains essentially no phosphate. The detergent composition is preferably also phosphonate-free i.e., contains at most 1.0 wt. % of phosphonate, preferably at most 0.8 wt. %, more preferably at most 0.5 wt. %, even more preferably at most 0.2 wt. % of phosphonate and still even more preferably contains essentially no phosphonate. Examples of phosphonates and phosphates are 1-hydroxyethane-1 ,1-diphosphonic acid (HEDP), diethylenetriamine-penta (methylenephosphonic acid) (DTPMP), ethylenediaminetetra- methylenephosphonate (EDTMP), tripolyphosphate and pyrophosphate. In particular phosphonates such as HEDP tend to be poorly biodegradable. It is also considered that phosphonates can reduce the efficiency of the bleach catalysts of the invention by scavenging the coordinate covalent bound iron- (Fe), Manganese- (Mn) and/or cobalt- (Co) cations.

Surfactant

In addition to the nonionic surfactant the detergent composition of the invention may comprise one or more further surfactants. Anionic surfactants may be chosen from the anionic surfactants described "Surface Active Agents" Vol. 1 , by Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958, in the current edition of "McCutcheon’s Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside-Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981. Preferably the surfactants used are saturated.

Amine oxide surfactants may also be used in the present invention as anti-redeposition surfactant. Examples of suitable amine oxide surfactants are C10-C18 alkyl dimethylamine oxide and C10-C18 acylamido alkyl dimethylamine oxide.

Anionic surfactants

If present the amount of anionic surfactant is preferably at most 5 wt. %, and more preferably at most 2 wt. % and even more preferably at most 1 .5 wt. %. Examples of suitable anionic surfactants are methylester sulphonates or sodium lauryl sulphate.

Advantageously the detergent according to the invention comprises essentially no anionic surfactant. Anionic surfactants are nowadays usually derived (in part) from nonrenewable carbon sources and often are poorly biodegradable. Hence having essentially no anionic surfactants shortens the ingredient list and reduces the environmental impact of the detergent composition.

Enzymes

The detergent composition of the invention preferably comprises enzyme. Examples of enzymes suitable for use in the cleaning compositions of this invention include lipases, cellulases, peroxidases, proteases (proteolytic enzymes), amylases (amylolytic enzymes) and others. Well-known and preferred examples of these enzymes are proteases, amylases, cellulases, peroxidases, mannanases, pectate lyases and lipases and combinations thereof, of which proteolytic and amylolytic enzymes are the more preferred. Enzymes may be added in liquid, granular or in encapsulated form to the composition, but preferably are not encapsulated. If enzymes are present the composition preferably also contains enzyme stabilizers such as polyalcohols/borax, calcium, formate or protease inhibitors like 4-formylphenyl boronic acid.

Preferred levels of protease are from 0.1 to 10 mg, more preferably from 0.2 to 5 mg, most preferably 0.4 to about 4 mg active protease per gram of the detergent composition. Preferred levels of amylase are from 0.01 to 5, more preferably from 0.02 to 2, most preferably from 0.05 to about 1 mg active amylase per gram of the detergent composition.

Dispersing polymers

The detergent composition of the invention beneficially comprises dispersing polymer. Dispersing polymers can be chosen from the group of anti-spotting agents and/or antiscaling agents. Examples of suitable anti-spotting polymeric agents include hydrophobically modified polycarboxylic acids such as Acusol™460 ND (ex Dow) and Alcosperse™747 by Nouryon, whereas also synthetic clays, and preferably those synthetic clays which have a high surface area can be useful to reduce spotting, in particular those formed where soil and dispersed remnants are present at places where the water collects on the floor when the water subsequently evaporates.

Suitable anti-scaling agents are water soluble dispersing polymers prepared from an allyloxybenzenesulfonic acid monomer, a methallyl sulfonic acid monomer, a copolymerizable nonionic monomer and a copolymerizable olefinically unsaturated carboxylic acid monomer as described in US5547612 or known as acrylic sulphonated polymers as described in EP851022. Polymers of this type include polyacrylate with methyl methacrylate, sodium methallyl sulphonate and sulphophenol methallyl ether such as Alcosperse™240 supplied (Nouryon). Also suitable is a terpolymer containing polyacrylate with 2-acrylamido-2 methylpropane sulphonic acid such as Acumer 3100 supplied by Dow. As an alternative, polymers and co-polymers of acrylic acid having a molecular weight between 500 and 20,000 can also be used, such as homo-polymeric polycarboxylic acid compounds with acrylic acid as the monomeric unit. The average weight of such homo-polymers in the acid form preferably ranges from 1 ,000 to 100,000 particularly from 3,000 to 10,000 e.g. Sokolan ™ PA 25 from BASF or Acusol™425 from Dow. Also suitable are polycarboxylates co-polymers derived from monomers of acrylic acid and maleic acid, such as CP5 from BASF. The average molecular weight of these polymers in the acid form preferably ranges from 4,000 to 70,000. Modified polycarboxylates like Sokalan™ CP50 from BASF or Alcoguard™4160 from Nouryon may also be used. Mixture of anti-scaling agents may also be used. Particularly useful is a mixture of organic phosphonates and polymers of acrylic acid.

If present, the preferred amount of dispersing polymer is from 0.1 to 6 wt. %, more preferably from 0.2 to 4 wt. %, and even more preferably from 0.3 to 2 wt. %.

Perfume and colorants

The detergent composition preferably comprises one or more colorants, one or more perfumes and more advantageously a mixture of at least one colorant and at least one perfume. Colorants are beneficially present in an amount of from 0.0001 to 8 wt. %, more preferably from 0.001 to 4 wt. % and even more preferably from 0.001 to 1.5 wt. %.

Perfume may be present in the range from 0.1 to 1 wt. %. Many suitable examples of perfumes are provided in the CTFA (Cosmetic, Toiletry and Fragrance Association) 1992 International Buyers Guide, published by CFTA Publications and OPD 1993 Chemicals Buyers Directory 80th Annual Edition, published by Schnell Publishing Co. In perfume mixtures preferably 15 to 25 wt. % are top notes. Top notes are defined by Poucher (Journal of the Society of Cosmetic Chemists 6(2):80 [1955]). Preferred topnotes are selected from citrus oils, linalool, linalyl acetate, lavender, dihydromyrcenol, rose oxide and cis-3-hexanol. Form of the detergent composition

The detergent composition of the invention may be in any suitable form, such as in the form of a liquid (e.g. gel), powder or a mixture thereof (e.g. a multi-compartmental capsule). They may be in unit-dose or non-unit dose form. Examples of unit-dose forms are tablets and capsules.

The detergent composition is preferably provided as a water-soluble or water- dispersible unit dose. Particularly preferred unit doses are in the form of pouches, which comprise at least one further non-shape stable ingredient, such as a liquid and/or powder; or in the form of tablets. For ease of use, the unit dose is sized and shaped as to fit in the detergent cup of a conventional domestic machine dishwasher. In a preferred embodiment, the unit-dose detergent composition has a unit weight of 5 to 50 grams, more preferably a unit weight of 10 to 30 grams, even more preferably a unit weight of 12 to 25 grams. Advantageous unit dose pouches preferably have more than one compartment. Advantageous unit dose tablets are those which have more than one visually distinct tablet region. Such regions can be formed by e.g. two distinct (colored) layers or a tablet having a main body and a distinct insert, such as forming a nested-egg. However oriented, one benefit of using multi-compartmental pouches/ multi-region tablets is that it can be used to reduce/prevent undesired chemical reactions between two or more ingredients during storage by physical segregation.

Preferably the unit dose detergent composition is wrapped to improve hygiene and consumer safety. The wrapper advantageously is based on water-soluble film which preferably a polyvinylalcohol (PVA) based film. Such wrapping prevents direct contact of the detergent composition with the skin of the consumer when placing the unit dose in the detergent cup/holder of a e.g. machine dishwasher. A further benefit of course is that the consumer also does not need to remove a water-soluble wrapping before use.

The detergent compositions according to the invention can be made using known methods and equipment in the field of detergent composition manufacturing.

Unless stated otherwise or is apparent from the context of the description, preferred embodiments mentioned for one aspect of the invention applies mutated mutandis to the other aspects of the invention as well. The below examples are meant to be illustrative and not limiting.

EXAMPLES

Example 1

A base solution was made by dissolving 0.02% of naphthol blue black dye (available from Sigma-Aldrich) in water and adjusting the pH to 10 (using 0.1 M bicarbonate). To 1 ml of this solution was added 1 ml water, 1 ml of 80 mM hydrogen peroxide and optionally 1 ml of a 100ppm stock solution of bleach catalyst (or water in the case of a catalyst free control). The final composition of the reaction mixtures contained 0.005 wt. % of naphthol blue black dye, hydrogen peroxide at a level of 20 mM and optionally 25ppm of bleach catalyst according to the invention, or (not according to the invention) bare Mn²⁺ (as water soluble MnSOt) as control. The final solution was incubated at 20 degrees Celsius for 20 hours after which the light absorbance was measured at 629nm using a UV-VIS spectrophotometer. The results are given in the Table 1 below.

Tablet dye-bleaching results at pH 10.

The experiment was repeated, at pH of 7.0 by adjusting the pH with phosphate in place of the bicarbonate. The results are shown in Table 2 below.

Table 2: dye-bleaching results at pH 7.0.

The results show that acid derivative of pyridine complexes of Mn²⁺, Fe²⁺, Fe³⁺ improve dye bleaching at 20 degrees Celsius and a pH of 10 or 7 compared to the use of these metal ions alone. These conditions are relevant for machine dishwash wash liquor conditions when operating at low temperatures.

Claims

1. A machine dishwash detergent composition comprising:

• from 0.1 to 20 wt. % non-ionic surfactant; and

• bleach; and

• from 0.005 to 20 wt. % of acid derivative of pyridine comprising one or more coordinate covalent bound iron- (Fe), Manganese- (Mn) and/or cobalt- (Co) cations; and wherein the composition comprises at most 1 wt. % of phosphate; and wherein the pH of a solution of 1 wt.% of the detergent composition in water as measured at 25 degrees Celsius is from 6.0 to 10.8.

2. A detergent composition according to claim 1 , wherein the acid derivative of pyridine comprises one or more carboxylic acid moieties, preferably comprising at least one formic acid-, acetic acid-, propionic acid moiety or combinations thereof.

3. A detergent composition according to claim 1 or claim 2, wherein the acid derivative of pyridine is based on the chemical formula C5H5N in which one or more H-atoms are replaced by acid moieties only.

4. A detergent composition according to any preceding claim, wherein the acid derivative of pyridine comprises picolinic acid, dipicolinic acid and more preferably dipicolinic acid.

5. A detergent composition according to any preceding claim, wherein the cation comprises Fe²⁺, Fe³⁺, Mn²⁺, Mn³⁺, Mn⁴⁺, Mn⁵⁺, Mn⁶⁺, Mn⁷⁺ and Co²⁺, Co³⁺ or mixtures thereof, preferably comprises Fe²⁺, Fe³⁺, Mn²⁺, Mn⁴⁺, Co²⁺, Co³⁺ or mixtures thereof and even more preferably comprises Fe³⁺, Fe²⁺, Mn²⁺ or mixtures thereof.

6. A detergent composition according to any preceding claim, wherein the composition comprises from 0.1 to 20 wt. % acid derivative of pyridine comprising one or more coordinate covalent bound Fe, Mn and/or Co cations, preferably from 0.2 to 10 wt. %, more preferably from 0.3 to 5 wt. %, even more preferably from 0.4 to 4 wt. %. A detergent composition according to any preceding claim, wherein the composition comprises further organic acid not comprising coordinate covalent bound Fe, Mn or Co cations, wherein the ratio of acid derivative of pyridine comprising one or more coordinate covalent bound Fe, Mn and/or Co cations to organic acid is from 1:4000 to 100:1 , preferably from 1 :100 to 20:1 , more preferably from 1 :50 to 1 : 1 and even more preferably from 1 :20 to 1 : 10. A detergent composition according to any preceding claim, wherein the pH of a solution of 1 wt. % of the detergent composition in water as measured at 25 degrees Celsius is from 6.0 to 10.6, preferably 6.5 to 10.6, more preferably 7.0 to 10.5, even more preferably from 7.5 to 10.2 and still even more preferably from 9.0 to 10.0. A detergent composition according to claim 6, wherein the amount of bleach is from 0.1 to 25 wt. %, preferably from 1.0 to 25 wt. %, more preferably from 2.0 to 20 wt. % and even more preferably is from 5 to 15 wt. %. A detergent composition according to any preceding claim, wherein the total amount of non-ionic surfactant is from 1 to 18 wt. %, preferably from 4 to 16 wt. % and more preferably from 6 to 12 wt.%. A detergent composition according to any preceding claim, wherein the composition further comprises bleach activator in an amount of from 0.1 to 10 wt. %, preferably from 0.5 to 5 wt. % and more preferably from 1.0 to 4 wt. %. A detergent composition according to any preceding claims, wherein the composition does not comprise further poorly biodegradable bleach catalyst and preferably comprises essentially no further bleach catalyst. A detergent composition according to any preceding claim, wherein the composition comprises at most 0.5 wt. % phosphate, preferably at most 0.2 wt. % phosphate and more preferably comprises essentially no phosphate. A detergent composition according to any preceding claim, wherein the composition comprises at most 1.0 wt. % of phosphonate, preferably at most 0.8 wt. %, more preferably at most 0.5 wt. %, even more preferably at most 0.2 wt. % phosphonate and still even more preferably comprises essentially no phosphonate. A detergent composition according to any preceding claim, wherein the detergent composition is in the form of a unit dose composition, preferably a tablet, more preferably a multi-region tablet and even more preferably a multi-region tablet having a water-soluble film.