CA2258218A1 - Low-alkaline mgda-containing dishwasher rinsing agent - Google Patents
Low-alkaline mgda-containing dishwasher rinsing agent Download PDFInfo
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- CA2258218A1 CA2258218A1 CA002258218A CA2258218A CA2258218A1 CA 2258218 A1 CA2258218 A1 CA 2258218A1 CA 002258218 A CA002258218 A CA 002258218A CA 2258218 A CA2258218 A CA 2258218A CA 2258218 A1 CA2258218 A1 CA 2258218A1
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- mgda
- acid
- dishwasher
- detergents
- rinsing agent
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Classifications
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- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
- C11D3/16—Organic compounds
- C11D3/26—Organic compounds containing nitrogen
- C11D3/33—Amino carboxylic acids
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- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
- C11D3/39—Organic or inorganic per-compounds
- C11D3/3947—Liquid compositions
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
- C11D7/22—Organic compounds
- C11D7/32—Organic compounds containing nitrogen
- C11D7/3245—Aminoacids
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
- C11D7/22—Organic compounds
- C11D7/32—Organic compounds containing nitrogen
- C11D7/3281—Heterocyclic compounds
Abstract
The invention provides a dishwasher rinsing agent which contains methyl glycine diacetic acid or its salts as the complexing agent, characaterized in that it does not exceed a pH of 10.4 in 0.5 % aqueous solution. The dishwasher rinsing agent of the invention operates at low pH and can even removal obstinate food remnants which cannot usually be removed with a dishwasher rinsing agent operating at such a pH. The novel rinsing agent has an excellent cleaning action especially on crockery contaminated with both milk and tea residues.
Description
CA 022~8218 1998-12-16 BENCKISER N.V.
World Trade Center AA
~ Schiphol Boulevard 229 NL-1118 BH Schiphol Airport Netherlands MGDA-contAi n; ng ~; 51 ~asher detergents of low alkalinity The invention relates to dishwasher detergents of low alkalinity which comprise methylglycinediacetic acid (MGDA) or a salt thereof, and which preferably have a reduced content of bleach.
Highly bleach-free alkaline dishwasher 15 detergents having a high content of complexing agents are known in the prior art. In the past, they were sold as compositions for household dishwashers and they are still used today for industrial equipment.
US-A 3 673 098 discloses bleach-free caustic 20 compositions which are based on KOH and nitrilotriacetic acid (NTA) .
FR-A 1 590 416 likewise discloses bleach-free caustic compositions which are based on alkali metal hydroxides, pyrophosphates and NTA.
Such compositions were later formulated without caustic alkalis, and the loss in performance was compensated for by adding chlorine bleach, as is described, for example, in US-A-3 826 748. These compositions without caustic alkalis still had a high 30 pH of more than 11.
The trend towards safer and environmentally friendlier compositions initially led to the replacement of strong complexing agents by builders and later to a new generation of mildly alkaline 35 dishwashing detergents with a pH of from 9 to 11. 5, the chlorine bleaches in which were replaced by oxygen bleaches and enzymes.
Good examples of such compositions can be found in EP-A-135 226, EP-A-135 227 and EP-A-414 197. In CA 022~8218 1998-12-16 these compositions, complexing agents are normally only present in small amounts, if at all.
EP-A-530 635 discloses acidic to mildly alkaline compositions (pH 5-9) which do not comprise complexing agents and are based on builders, enzymes and, optionally, oxygen bleaches.
DE-A-3 833 047 discloses acidic compositions (pH 2-6) containing hydrolases and builders or complexing agents. The examples disclose compositions with a high NTA or EDTA content (up to 30%). Although these compositions can readily remove, for example, tea residues, their effect in the case of milk residues, measured on a scale from 0 to 10, is always below 5.
The use of other biodegradable complexing agents, such as ~-alaninediacetic acid (~-ADA) and isoserinediacetic acid (ISDA) in detergents is disclosed in DE-A-3 829 847 and DE-A-4 036 995. Where these publications include application examples of dishwasher detergents, the dishwasher detergents have, in about 0.5% strength aqueous solution, a pH of more than 10.5.
Moreover, these compounds have a significantly lower complexing action than NTA and are only a poor replacement for the latter in the finished composition.
DE-A-4 319 935 discloses the use of MGDA in dishwasher detergents without giving an example. In a GDCH [Association of German Chemists] lecture on May 30, 1995, one of the inventors of DE-A-4 319 935 published the use of methylglycinediacetic acid (MGDA) as a complexing agent for cleaning equipment in the milk industry on an industrial scale and in dishwashing detergents having a pH in solution of more than 10.5.
The same information can also be found in the "Prel;m;n~ry Technical Information, Trilon~ ES 9964n, April 1995, from BASF AG. The dishwashing detergents disclosed therein comprise 5-30% of MGDA and 1.12% of active oxygen, MGDA achieving a comparable result to NTA in inhibiting encrustation (formation of calcium carbonate deposits). The effectiveness of the CA 022~8218 1998-12-16 dishwashing detergents on milk residues or tea residues is not mentioned. MGDA should, however, be better able to dissolve calcium phosphate residues than NTA during dairy cleaning. During dairy cleaning, the working range is usually strongly alkaline.
In an article in the SOFW [Soaps, Oils, Fats and Waxes] Journal 122, 1996, 392, the use of MGDA in laundry detergents is proposed. Particularly in the ~ case of blood-stained laundry, MGDA is said to have a better effect than phosphonates, and in the case of tea-soiled laundry has approximately the same effect as phosphonates. The same publication discloses that MGDA
in a dishwashing detergent, in a similar manner to NTA, exhibits very good encrustation inhibition on glass, metal and porcelain, a dishwashing detergent being disclosed which, in solution, produces a pH of more than 10.5. It is also proposed to use MGDA under very strongly alkaline conditions for dairy cleaning.
The dishwasher detergents proposed to date which use complexing agents therefore have the disadvantage that they are either effective at a relatively high pH or do not have sufficient detergency for certain food residues, in particular for milk residues and tea residues.
- 25 An object of the invention is to provide a dishwasher detergent which is effective not only at a low pH, but moreover also removes difficult-to-remove food residues which dishwasher detergents effective at such a pH are usually unable to remove satisfactorily.
In particular, such a dishwashing detergent should have excellent detergency in the case of dishes soiled either with milk or else with tea residues. This object is achieved by a dishwasher detergent which comprises methylglycinediacetic acid or salts thereof as complexing agent and which, in about 0.5% strength aqueous solution, does not exceed a pH of 10.4.
Milk residues are composed of a mixture of denatured proteins (casein), fats, sugars and mineral deposits and consist of about 70% of calcium phosphate CA 022~8218 1998-12-16 (Ca3(PO4)2). Complexing agents thus have an essential influence on the removal of milk residues because they dissolve calcium phosphates by complexing the calcium ions.
Tea residues, as well, are based inter alia on Ca deposits, which form when tea is made using hard water. However, tea residues usually place different demands on a dishwasher detergent to milk residues, something which is immediately evident from the fact 10 that the detergent disclosed in DE-A 3 833 047 satisfactorily removes tea residues in the acidic range (pH 2-6), but is not convincing in the case of milk residues.
The ability (based on the weight of the complexing agent) to complex calcium ions at a certain pH depends on the stability constant of the calcium complex (pKc), the acidic character of the complexing agent (pK3) and on its molecular weight.
Although, at a pH of 11, MGDA has a higher theoretical degree of complexation for calcium carbonate than NTA (as has been disclosed in the abovementioned GDCH lecture and which can be calculated theoretically), at a pH of 7 and 10.4 and for calcium phosphates, the result is different.
In fact, at a pH of 10.4, the theoretical degree of complexation for calcium phosphates is 360 mg/g when using NTA and 340 mg/g when using MGDA, and at a pH of 8, the theoretical values are 510 mg/g for NTA and 490 mg/g for MGDA.
With reference to these theoretical considerations, it therefore follows that MGDA has a poorer complexing action on calcium phosphates in the case of a dishwashing detergent which, in about 0.5%
strength aqueous solution, produces a pH of less than 10.4, and thus should be less able to remove milk residues than the conventional NTA.
Also, MGDA was used in the prior art only in dishwashing detergents which have, in about 0.5%
strength aqueous solution, a pH of more than 10.4.
CA 022~82l8 l998-l2-l6 At a lower pH, the use of NTA is preferable;
this is said to have a better complexing action than MGDa on calcium phosphates at such a pH, and in addition satisfactorily removes tea residues in the acidic range (pH 2-6) (DE-A 38 33 047).
Surprisingly, it has, however, been found according to the invention that dishwashing detergents which comprise MGDA and which produce an approximately 0.5% strength aqueous solution having a pH of up to 10.4 are better able to remove tea residues and also milk residues and, overall, have better detergency than dishwashing detergents which comprise another complexing agent instead of MGDA, such as the conventional NTA.
Surprisingly, it has also been found that for a dishwashing detergent according to the invention which has a sufficient amount of complexing agent MGDA, the amount of oxygen bleach can be reduced without thereby impairing the detergency and, in particular, the ability to remove milk residues and tea residues. This surprising finding even opens up the possibility of dispensing completely with the use of oxygen bleach when a sufficiently large amount of complexing agent is used.
The dishwashing detergent according to the invention can be liquid or pulverulent and can likewise be in the form of a single-layer or multilayer tablet.
Corresponding dosing forms and methods for their preparation are known to the person skilled in the art.
3 0 The dishwasher detergents according to the invention preferably comprise one or more enzymes, such as, for example, amylase, protease, lipase or cellulase. The best cleaning results are obtained by the combined use of amylase and protease. For the pH
ranges described here, these enzymes can be used particularly effectively; thus, for example, the temperature-stable amylase Termamyl (Novo) achieves the optimum of its activity spectrum at pH 7-8. The enzymes are used in granular form or in solutions having CA 022~8218 1998-12-16 standard commercial concentrations or activities, it being possible for the content of enzymes to be 0.5-6%
by weight, preferably 1-4% by weight.
Examples of suitable builders are homopolymers and copolymers of polycarboxylic acids and their partially or completely neutralized salts, monomeric polycarboxylic acids and hydroxycarboxylic acids and their salts, carbonates, bicarbonates, borates, phosphates, silicates, aluminosilicates and mixtures of such substances.
Preferred salts of the abovementioned compounds are the ammonium and/or alkali metal salts, i.e. the lithium, sodium, potassium and rubidium salts, and a particularly preferred salt is the sodium salt.
Suitable polycarboxylic acids are acyclic, alicyclic, heterocyclic and aromatic carboxylic acids, in which case they contain at least two carboxyl groups which are in each case separated from one another by, preferably, no more than two carbon atoms.
Polycarboxylates which comprise two carboxyl groups include, for example, water-soluble salts of succinic acid, malonic acid, (ethylenedioxy)diacetic acid, maleic acid, diglycolic acid, tartaric acid, tartronic acid and fumaric acid. Polycarboxylates which contain three carboxyl groups include, for example, water-soluble citrate. Correspondingly, a suitable hydroxycarboxylic acid is, for example, citric acid.
Another specific builder for dishwasher detergents which can be mentioned is a polymer, derived from aspartic acid HOOC-CH(NH2)-CH2-COOH
containing monomer units of the formula and ~ ~a CA 022~8218 1998-12-16 Another suitable polycarboxylic acid is the homopolymer of acrylic acid.
Borate builders which can be used are, in addition to borates such as sodium borate, also those builders which liberate borates under the detergent storage conditions or washing conditions.
Suitable phosphates are polyphosphates, such as tripolyphosphate, pyrophosphate, orthophosphate and the polymeric metaphosphate. Examples which may be mentioned are alkali metal tripolyphosphates, sodium, potassium and ammonium pyrophosphate, sodium and potassium orthophosphate and sodium polymetaphosphate, the degree of polymerization in which preferably being from 5 to 21.
Suitable silicates are sodium silicates such as sodium disilicate, sodium metasilicate and crystalline phyllosilicates. Sodium aluminosilicates (zeolites) are also suitable.
Other suitable builders are disclosed in WO 95101416, to the contents of which express reference is hereby made.
Particular preference is given to a builder system of the salt of a hydroxycarboxylic acid or of the mixture of a hydroxycarboxylic acid and the salt of a hydroxycarboxylic acid. Both the hydroxycarboxylic acid and the salt of the hydroxycarboxylic acid can be replaced completely or partially by tripolyphosphate, although this is not preferable.
The builder system preferably consists of a hydroxypolycarboxylic acid containing 2-4 carboxyl groups (or acidic inorganic salts), which can be mixed with its salt to adjust the pH. Citric acid or a mixture of sodium citrate with citric acid is preferably used. For adjustment of the pH, which is required according to the invention, mixtures having a major proportion of citric acid, for example, are suitable, depending on the other constituents of the mixture.
CA 022~8218 1998-12-16 The water content of the liquid dishwashing detergents can be 40-80% by weight.
The liquid dishwashing detergents also comprise 0.2-5.0% by weight, preferably 0.5-2% by weight, of a thickener. Suitable thickeners are high molecular organic polymers having molecular weights of from 5 x 105 to ca. 5 x 106, which are composed of olefinically unsaturated carboxylic acids. Carboxyvinyl polymers, as are commercially available, for example, from B.F. Goodrich under the production name "Carbopol", have proven to be highly suitable.
Inorganic compounds which have thickening properties for this product composition can also be used. Examples thereof are natural or synthetic thickeners based on different silicate structures. Their use is described in various patents, for example in US-A-4 933 101 or EP-A2-0 407 187.
Suitable surfactants are, for example, nonionic surfactants. These include, for example, water-soluble ethoxylated C6l6 fatty acid alcohols and C6l6 mixed ethoxylated, propoxylated fatty acid alcohols and mixtures thereof and also polyglucosides.
Another class of nonionic surfactants includes polyhydroxy fatty acid amides.
Other suitable surfactants are disclosed in WO 95/01416, to the contents of which express reference is hereby made.
The dishwasher detergent according to the invention can also comprise one or more foam control agents. Suitable foam control agents for this purpose are all those used in this field, such as, for example, silicones and paraffin oil.
The foam control agents are preferably present in the dishwasher detergent according to the invention in amounts of less than 5% by weight of the total weight of the detergent.
The dishwasher detergents according to the invention may comprise, as bleach, bleaches which are preferably chlorine-free and liberate active oxygen, CA 022~8218 1998-12-16 such as inorganic perhydrates or organic peracids and the salts thereof.
Examples of inorganic perhydrates are perborates, percarbonates and persulfates such as peroxymonopersulfate. The inorganic perhydrates are normally alkali metal salts, such as lithium, sodium, potassium or rubidium salts, in particular sodium salt.
The inorganic perhydrates may be present in the detergent as crystalline solids without further protection. For certain perhydrates, it is however advantageous to use them as granular compositions provided with a coating which gives the granular products a longer shelf life.
The preferred perborate is sodium perborate, which can be in the form of the monohydrate having the formula NaBO2H2O2 or in the form of the tetrahydrate of the formula NaBO2H2O2.3H2O.
The preferred percarbonate is sodium percarbonate of the formula 2Na2CO3.3H2O2- The percarbonate is preferably used for increasing its stability in a coated form.
Organic peracids include all organic peracids traditionally used as bleaches, including, for example, perbenzoic acid and peroxycarboxylic acids such as mono- or diperoxyphthalic acid, 2-octyldiperoxysuccinic acid, diperoxydodecanedicarboxylic acid, diperoxy-azelaic acid and imidoperoxycarboxylic acid and, optionally, the salts thereof.
The dishwasher detergent according to the invention can also comprise one or more bleach activators. These are preferably used in detergents for dishwashing cycles at temperatures in the range below 60~C in order to achieve an adequate bleaching action.
Particularly suitable examples are N- and O-acyl compounds, such as acylated amines, acylated glycolurils or acylated sugar compounds. Preference is given to N,N,N',N'-tetraacetylethylenediamine (TAED), pentaacetylglucose (PAG) and tetraacetylglycoluril (TAGU). Other suitable bleach activators are, however, CA 022~8218 1998-12-16 catalytically active metal complexes and, preferably, transition metal complexes. TAED is most preferable.
Other suitable bleach activators are disclosed in WO 95/01416, to the contents of which express reference is hereby made.
By using MGDA at a relatively low pH, it is, however, possible to reduce the use of bleaches, and the dishwasher detergents according to the invention preferably comprise an oxygen bleach in an amount of less than 1% by weight, based on the active oxygen. The amount of bleach activator used is correspondingly adjusted.
In one embodiment, the dishwasher detergents have a large content of MGDA, such as 25% or more, preferably 30% or more, in each case based on the free acid, and an oxygen bleach is dispensed with.
The dishwasher detergent according to the invention can also comprise a silver/copper corrosion inhibitor. This term encompasses agents which are intended to prevent or reduce the tarnishing of non-ferrous metals, in particular of silver and copper.
Preferred silver/copper corrosion inhibitors are benzotriazole or bis-benzotriazole and substituted derivatives thereof.
Other suitable agents are organic and/or inorganic redox-active substances and paraffin oil.
Benzotriazole derivatives are those compounds in which the available substitution sites on the aromatic ring are partially or completely substituted.
Suitable substituents are linear or branch-chain Cl20-alkyl groups and hydroxyl, thio, phenyl or halogen such as fluorine, chlorine, bromine and iodine. A preferred substituted benzotriazole is tolyltriazole.
Suitable bis-benzotriazoles are those in which the benzotriazole groups are each linked in the 6-position by a group X, where X may be a bond, a straight-chain alkylene group which is optionally substituted by one or more Clg-alkyl groups and preferably has 1-6 carbon atoms, a cycloalkyl radical CA 022~8218 1998-12-16 having at least 5 carbon atoms, a carbonyl group, a sulfuryl group, an oxygen atom or a sulfur atom. The aromatic rings of the bis-benzotriazoles may be substituted as defined above for benzotriazole.
Suitable organic redox-active substances are, for example, ascorbic acid, indole, methionine, an N-mono-(C1-C4-alkyl)glycine, an N,N-di-(Cl-C4-alkyl)glycine, 2-phenylglycine or a coupler and/or developer compound chosen from the group consisting of diaminopyridines,aminohydroxypyridines, dihydroxypyridines, heterocyclic hydrazones, aminohydroxypyrimidines,dihydroxypyrimidines, tetraaminopyrimidines,triaminohydroxypyrimidines, diaminodihydroxypyrimidines, dihydroxynaphthalenes, 15 naphthols, pyrazolones, hydroxyquinolines, aminoquinolines, of primary aromatic amines which, in the ortho-, meta- or paraposition, have another hydroxyl or amino group which is free or substituted by C1-C4-alkyl or C2-C4-hydroxyalkyl groups, and of di- or 20 trihydroxybenzenes.
Suitable inorganic redox-active substances are, for example, metal salts and/or metal complexes chosen from the group consisting of manganese, titanium, zirconium, hafnium, vanadium, cobalt and cerium salts 25 and/or complexes, the metals being in one of the oxidation states II, III, IV, V or VI.
Particularly suitable metal salts and/or metal complexes are chosen from the group consisting of MnSO4, Mn(II) citrate, Mn(II) stearate, Mn(II) acetylacetonate, Mn(II)[1-hydroxyethane-1,1-diphosphonate], V2O5, V2O4, VO2, TioSo4, K2TiF6, K2ZrF6, CoSO4, Co (NO3)2 and Ce(NO3) 3.
Organic and inorganic redox-active substances which are suitable as silver/copper corrosion inhibitors are also mentioned in WO 94/26860 and WO 94/26859, to the contents of which reference is hereby made.
Suitable paraffin oils are predominantly branched aliphatic hydrocarbons having a number of CA 022~82l8 l998-l2-l6 carbon atoms in the range from 20 to 50. Preference is given to the paraffin oil chosen from predominantly branched-chain C25g5 species having a ratio of cyclic to noncyclic hydrocarbons of from 1:10 to 2:1, preferably from 1:5 to 1:1.
If a silver/copper corrosion inhibitor is present in the dishwasher detergent according to the invention, it is preferably present in an amount of from 0.01 to 5% by weight, particularly preferably in an amount of from 0.1 to 2% by weight, of the total weight.
In the embodiment of the invention in which the content of MGDA in the dishwasher detergent is sufficiently high, such as 25% or more, preferably 30%
or more, in each case based on the free acid, with the result that bleach can be omitted, it is also possible to dispense with a silver/copper corrosion inhibitor.
Other customary additives are, for example, dyes and perfumes and optionally in the case of liquid products, preservatives, suitable examples of which are compounds based on isothiazolinone.
The dishwasher detergents according to the invention are not caustic and therefore do not require particularly secured packaging. A good detergency can be achieved using a relatively low use amount of 15-20 g of powder or 20-50 ml of liquid detergent.
According to current knowledge, none of the ingredients is either toxic or detrimental to health in any other way. The detergents described here thus also represent an environment- and consumer-friendly alternative to conventional detergents containing complexing agents which are effective in the strongly basic range.
The methylglycinediacetic acid used according to the invention has the following structural formula:
HO2C ~ _<CH3 HO2C-- CC~2H
CA 022~8218 1998-12-16 The methylglycinediacetic acid is particularly preferably used as the free acid or as the sodium or potassium salt, and is preferably present in the dishwashing detergent in an amount of from 3% to 90%, based on the free acid.
In bleach-free dishwasher detergents which are based on phosphates as the principal constituent of the builder system, the amount of MGDA is preferably at least 5%, based on the free acid.
According to the invention, it is essential that an approximately 0.5% strength aqueous solution of the detergent has a pH of no more than 10.4. The pH of an approximately 0.5% strength aqueous solution of the detergent according to the invention is preferably from more than 6 to 10.4, particularly preferably from 7 to 10 . O .
The following comparative experiment demonstrates that the dishwashing detergents proposed in the article in the SOFW Journal 122, 1996, 392-397, have in 0.5% strength aqueous solutions, a pH of more than 10.4. The disclosure of this article is therefore in agreement with the theoretical expectation that MGDA
is an excellent complexing agent at a pH of more than 10.4, but is inferior to the traditional NTA at a pH of 10.4 or below.
Comparative Experiment 30 In agreement with the disclosure of the article in the SOFW Journal 122, 1996, 392-397, dishwashing detergents are prepared from the following constituents:
Sodium citrate dihydrate Sodium carbonate Sodium hydrogen carbonate Sodium perborate monohydrate TAED
CA 022~82l8 l998-l2-l6 C13-C1s-OxO alcohol + 4 mol of PO + 2 mol of EO
MGDA (trisodium salt of methylglycinediacetic acid) (77% strength solution in water) = TRILON ES 9964 obtainable from BASF AG.
The table below shows the amounts of the respective constituents in g and %. The constituents were dissolved in one litre of water having a hardness of 10~, and the pH of the solution was determined in each case. The total amount of the constituents (100%) 10 is in each case 4 g, corresponding to a 0. 4% strength concentration, as is disclosed in Figure 14 of the article.
MGDA in pure form is not available commercially, and therefore a 77% strength solution in water was used. A relatively large amount of the commercially available product therefore had to be used, as the Table shows. For MGDA, the Table gives two values in each case. The first value is the amount in g of the commercial product, and the second value 20 corresponds to the corresponding amount of pure substance (100%).
SOFW Journal 122, 1996, 392-397 Example 1 Example 2 Example 3 Amounts in g (%' Citrate 2 (50%) 1.6 (40%) 1 (25%) Carbonate 1 (25%) 1 (25%) 1 (25%) Hydrogen-carbonate 0.36 (9%) 0.36 (9%) 0.36 (9%) Perborate 0.28 (7%) 0.28 (7%) 0.28 (7%) TAED 0.08 (2%) 0.08 (2%) 0.08 (2%) Nonionic 0. 08 (2%) 0.08 (2%) 0.08 (2%) surfactant MGDA 0.26/0.2 (5%) 0.78/0.6 (15%) 1.56/1.2 (30%) (77% solu-tion)/(100%) Total 4.06 4 4.18 4 4.36 4 ¦pH ¦10. 64 ¦ 10.79 ¦ 10.82 CA 022~8218 1998-12-16 Although the pH of 0.5% strength solutions of the agents was not determined directly, the pH of 0.4%
strength solutions was determined. At a higher concentration of the detergent, the solutions of the detergent will obviously have the same or, more probably, a higher pH.
The example below shows that when some of the builder of a dishwasher detergent is replaced by methylglycinediacetic acid, at a low pH, excellent detergency can be achieved and, in particular, contrary to the theoretical expectations, the ability to remove milk residues and tea residues is greater than in the case of other traditional complexing agents such as NTA. The example illustrates the invention.
ExA~nple Liquid dishwashing detergents having a composition as given in Table 1 were prepared (both in accordance with the invention using MGDA and using the NTA customary in the prior art), and their detergency was determined using dishes soiled with both milk and tea residues. In this experiment, the DIN Standard No. 44990, Part 2 was essentially followed. A Bosch SMS 5062 dishwasher was used. The water had a hardness of 19~ German hardness (3.39 mmol of calcium carbonate), the temperature of the water was 65~C and 20 ml of detergent were used in each case. The detergency results were evaluated on a scale from 1 to 5 (where 5 is 100% clean dishes) and are also given in Table 1.
The nonionic surfactant is a customary, low-foaming ethoxylated and propoxylated fatty alcohol.
Customary proteases and amylases are used.
CA 022~82l8 l998-l2-l6 Table 1 NTA I MGDA I NTA II MGDA NTA MGDA
II III III
Water 1.47 0.00 3.57 0.57 7.67 3.77 Citric acid 8.00 9.47 5.90 8.90 1.80 5.70 MGDA (35.6%) 0.00 87.1 0.00 87.1 0.00 87.1 NTA (35.6%) 87.1 0.00 87.1 0.00 87.1 0.00 Nonionic 1.50 1.50 1.50 1.50 1.50 1.50 surfactants Protease 0.50 0.50 0.50 0.50 0.50 0.50 Amylase 0.50 0.50 0.50 0.50 0.50 0.50 Preservative 0.03 0.03 0.03 0.03 0.03 0.03 Perfume 0.10 0.10 0.10 0.10 0.10 0.10 Thickener 0.80 0.80 0.80 0.80 0.80 0.80 ioo loo loo loo loo loo pH (0.5% 8.1 8.0 9.4 9.3 10.4 10.3 strength) Tea 4.2 4.7 4.4 4.8 4.6 5.0 Milk 3.1 3.3 3.2 3.3 3.0 3.4 The results in Table 1 show that in a pH range below 10. 4 detergents which comprise MGDA achieve surprisingly better results both in the removal of milk residues and in the removal of tea residues than the corresponding detergents which comprise the customary NTA instead of MGDA.
World Trade Center AA
~ Schiphol Boulevard 229 NL-1118 BH Schiphol Airport Netherlands MGDA-contAi n; ng ~; 51 ~asher detergents of low alkalinity The invention relates to dishwasher detergents of low alkalinity which comprise methylglycinediacetic acid (MGDA) or a salt thereof, and which preferably have a reduced content of bleach.
Highly bleach-free alkaline dishwasher 15 detergents having a high content of complexing agents are known in the prior art. In the past, they were sold as compositions for household dishwashers and they are still used today for industrial equipment.
US-A 3 673 098 discloses bleach-free caustic 20 compositions which are based on KOH and nitrilotriacetic acid (NTA) .
FR-A 1 590 416 likewise discloses bleach-free caustic compositions which are based on alkali metal hydroxides, pyrophosphates and NTA.
Such compositions were later formulated without caustic alkalis, and the loss in performance was compensated for by adding chlorine bleach, as is described, for example, in US-A-3 826 748. These compositions without caustic alkalis still had a high 30 pH of more than 11.
The trend towards safer and environmentally friendlier compositions initially led to the replacement of strong complexing agents by builders and later to a new generation of mildly alkaline 35 dishwashing detergents with a pH of from 9 to 11. 5, the chlorine bleaches in which were replaced by oxygen bleaches and enzymes.
Good examples of such compositions can be found in EP-A-135 226, EP-A-135 227 and EP-A-414 197. In CA 022~8218 1998-12-16 these compositions, complexing agents are normally only present in small amounts, if at all.
EP-A-530 635 discloses acidic to mildly alkaline compositions (pH 5-9) which do not comprise complexing agents and are based on builders, enzymes and, optionally, oxygen bleaches.
DE-A-3 833 047 discloses acidic compositions (pH 2-6) containing hydrolases and builders or complexing agents. The examples disclose compositions with a high NTA or EDTA content (up to 30%). Although these compositions can readily remove, for example, tea residues, their effect in the case of milk residues, measured on a scale from 0 to 10, is always below 5.
The use of other biodegradable complexing agents, such as ~-alaninediacetic acid (~-ADA) and isoserinediacetic acid (ISDA) in detergents is disclosed in DE-A-3 829 847 and DE-A-4 036 995. Where these publications include application examples of dishwasher detergents, the dishwasher detergents have, in about 0.5% strength aqueous solution, a pH of more than 10.5.
Moreover, these compounds have a significantly lower complexing action than NTA and are only a poor replacement for the latter in the finished composition.
DE-A-4 319 935 discloses the use of MGDA in dishwasher detergents without giving an example. In a GDCH [Association of German Chemists] lecture on May 30, 1995, one of the inventors of DE-A-4 319 935 published the use of methylglycinediacetic acid (MGDA) as a complexing agent for cleaning equipment in the milk industry on an industrial scale and in dishwashing detergents having a pH in solution of more than 10.5.
The same information can also be found in the "Prel;m;n~ry Technical Information, Trilon~ ES 9964n, April 1995, from BASF AG. The dishwashing detergents disclosed therein comprise 5-30% of MGDA and 1.12% of active oxygen, MGDA achieving a comparable result to NTA in inhibiting encrustation (formation of calcium carbonate deposits). The effectiveness of the CA 022~8218 1998-12-16 dishwashing detergents on milk residues or tea residues is not mentioned. MGDA should, however, be better able to dissolve calcium phosphate residues than NTA during dairy cleaning. During dairy cleaning, the working range is usually strongly alkaline.
In an article in the SOFW [Soaps, Oils, Fats and Waxes] Journal 122, 1996, 392, the use of MGDA in laundry detergents is proposed. Particularly in the ~ case of blood-stained laundry, MGDA is said to have a better effect than phosphonates, and in the case of tea-soiled laundry has approximately the same effect as phosphonates. The same publication discloses that MGDA
in a dishwashing detergent, in a similar manner to NTA, exhibits very good encrustation inhibition on glass, metal and porcelain, a dishwashing detergent being disclosed which, in solution, produces a pH of more than 10.5. It is also proposed to use MGDA under very strongly alkaline conditions for dairy cleaning.
The dishwasher detergents proposed to date which use complexing agents therefore have the disadvantage that they are either effective at a relatively high pH or do not have sufficient detergency for certain food residues, in particular for milk residues and tea residues.
- 25 An object of the invention is to provide a dishwasher detergent which is effective not only at a low pH, but moreover also removes difficult-to-remove food residues which dishwasher detergents effective at such a pH are usually unable to remove satisfactorily.
In particular, such a dishwashing detergent should have excellent detergency in the case of dishes soiled either with milk or else with tea residues. This object is achieved by a dishwasher detergent which comprises methylglycinediacetic acid or salts thereof as complexing agent and which, in about 0.5% strength aqueous solution, does not exceed a pH of 10.4.
Milk residues are composed of a mixture of denatured proteins (casein), fats, sugars and mineral deposits and consist of about 70% of calcium phosphate CA 022~8218 1998-12-16 (Ca3(PO4)2). Complexing agents thus have an essential influence on the removal of milk residues because they dissolve calcium phosphates by complexing the calcium ions.
Tea residues, as well, are based inter alia on Ca deposits, which form when tea is made using hard water. However, tea residues usually place different demands on a dishwasher detergent to milk residues, something which is immediately evident from the fact 10 that the detergent disclosed in DE-A 3 833 047 satisfactorily removes tea residues in the acidic range (pH 2-6), but is not convincing in the case of milk residues.
The ability (based on the weight of the complexing agent) to complex calcium ions at a certain pH depends on the stability constant of the calcium complex (pKc), the acidic character of the complexing agent (pK3) and on its molecular weight.
Although, at a pH of 11, MGDA has a higher theoretical degree of complexation for calcium carbonate than NTA (as has been disclosed in the abovementioned GDCH lecture and which can be calculated theoretically), at a pH of 7 and 10.4 and for calcium phosphates, the result is different.
In fact, at a pH of 10.4, the theoretical degree of complexation for calcium phosphates is 360 mg/g when using NTA and 340 mg/g when using MGDA, and at a pH of 8, the theoretical values are 510 mg/g for NTA and 490 mg/g for MGDA.
With reference to these theoretical considerations, it therefore follows that MGDA has a poorer complexing action on calcium phosphates in the case of a dishwashing detergent which, in about 0.5%
strength aqueous solution, produces a pH of less than 10.4, and thus should be less able to remove milk residues than the conventional NTA.
Also, MGDA was used in the prior art only in dishwashing detergents which have, in about 0.5%
strength aqueous solution, a pH of more than 10.4.
CA 022~82l8 l998-l2-l6 At a lower pH, the use of NTA is preferable;
this is said to have a better complexing action than MGDa on calcium phosphates at such a pH, and in addition satisfactorily removes tea residues in the acidic range (pH 2-6) (DE-A 38 33 047).
Surprisingly, it has, however, been found according to the invention that dishwashing detergents which comprise MGDA and which produce an approximately 0.5% strength aqueous solution having a pH of up to 10.4 are better able to remove tea residues and also milk residues and, overall, have better detergency than dishwashing detergents which comprise another complexing agent instead of MGDA, such as the conventional NTA.
Surprisingly, it has also been found that for a dishwashing detergent according to the invention which has a sufficient amount of complexing agent MGDA, the amount of oxygen bleach can be reduced without thereby impairing the detergency and, in particular, the ability to remove milk residues and tea residues. This surprising finding even opens up the possibility of dispensing completely with the use of oxygen bleach when a sufficiently large amount of complexing agent is used.
The dishwashing detergent according to the invention can be liquid or pulverulent and can likewise be in the form of a single-layer or multilayer tablet.
Corresponding dosing forms and methods for their preparation are known to the person skilled in the art.
3 0 The dishwasher detergents according to the invention preferably comprise one or more enzymes, such as, for example, amylase, protease, lipase or cellulase. The best cleaning results are obtained by the combined use of amylase and protease. For the pH
ranges described here, these enzymes can be used particularly effectively; thus, for example, the temperature-stable amylase Termamyl (Novo) achieves the optimum of its activity spectrum at pH 7-8. The enzymes are used in granular form or in solutions having CA 022~8218 1998-12-16 standard commercial concentrations or activities, it being possible for the content of enzymes to be 0.5-6%
by weight, preferably 1-4% by weight.
Examples of suitable builders are homopolymers and copolymers of polycarboxylic acids and their partially or completely neutralized salts, monomeric polycarboxylic acids and hydroxycarboxylic acids and their salts, carbonates, bicarbonates, borates, phosphates, silicates, aluminosilicates and mixtures of such substances.
Preferred salts of the abovementioned compounds are the ammonium and/or alkali metal salts, i.e. the lithium, sodium, potassium and rubidium salts, and a particularly preferred salt is the sodium salt.
Suitable polycarboxylic acids are acyclic, alicyclic, heterocyclic and aromatic carboxylic acids, in which case they contain at least two carboxyl groups which are in each case separated from one another by, preferably, no more than two carbon atoms.
Polycarboxylates which comprise two carboxyl groups include, for example, water-soluble salts of succinic acid, malonic acid, (ethylenedioxy)diacetic acid, maleic acid, diglycolic acid, tartaric acid, tartronic acid and fumaric acid. Polycarboxylates which contain three carboxyl groups include, for example, water-soluble citrate. Correspondingly, a suitable hydroxycarboxylic acid is, for example, citric acid.
Another specific builder for dishwasher detergents which can be mentioned is a polymer, derived from aspartic acid HOOC-CH(NH2)-CH2-COOH
containing monomer units of the formula and ~ ~a CA 022~8218 1998-12-16 Another suitable polycarboxylic acid is the homopolymer of acrylic acid.
Borate builders which can be used are, in addition to borates such as sodium borate, also those builders which liberate borates under the detergent storage conditions or washing conditions.
Suitable phosphates are polyphosphates, such as tripolyphosphate, pyrophosphate, orthophosphate and the polymeric metaphosphate. Examples which may be mentioned are alkali metal tripolyphosphates, sodium, potassium and ammonium pyrophosphate, sodium and potassium orthophosphate and sodium polymetaphosphate, the degree of polymerization in which preferably being from 5 to 21.
Suitable silicates are sodium silicates such as sodium disilicate, sodium metasilicate and crystalline phyllosilicates. Sodium aluminosilicates (zeolites) are also suitable.
Other suitable builders are disclosed in WO 95101416, to the contents of which express reference is hereby made.
Particular preference is given to a builder system of the salt of a hydroxycarboxylic acid or of the mixture of a hydroxycarboxylic acid and the salt of a hydroxycarboxylic acid. Both the hydroxycarboxylic acid and the salt of the hydroxycarboxylic acid can be replaced completely or partially by tripolyphosphate, although this is not preferable.
The builder system preferably consists of a hydroxypolycarboxylic acid containing 2-4 carboxyl groups (or acidic inorganic salts), which can be mixed with its salt to adjust the pH. Citric acid or a mixture of sodium citrate with citric acid is preferably used. For adjustment of the pH, which is required according to the invention, mixtures having a major proportion of citric acid, for example, are suitable, depending on the other constituents of the mixture.
CA 022~8218 1998-12-16 The water content of the liquid dishwashing detergents can be 40-80% by weight.
The liquid dishwashing detergents also comprise 0.2-5.0% by weight, preferably 0.5-2% by weight, of a thickener. Suitable thickeners are high molecular organic polymers having molecular weights of from 5 x 105 to ca. 5 x 106, which are composed of olefinically unsaturated carboxylic acids. Carboxyvinyl polymers, as are commercially available, for example, from B.F. Goodrich under the production name "Carbopol", have proven to be highly suitable.
Inorganic compounds which have thickening properties for this product composition can also be used. Examples thereof are natural or synthetic thickeners based on different silicate structures. Their use is described in various patents, for example in US-A-4 933 101 or EP-A2-0 407 187.
Suitable surfactants are, for example, nonionic surfactants. These include, for example, water-soluble ethoxylated C6l6 fatty acid alcohols and C6l6 mixed ethoxylated, propoxylated fatty acid alcohols and mixtures thereof and also polyglucosides.
Another class of nonionic surfactants includes polyhydroxy fatty acid amides.
Other suitable surfactants are disclosed in WO 95/01416, to the contents of which express reference is hereby made.
The dishwasher detergent according to the invention can also comprise one or more foam control agents. Suitable foam control agents for this purpose are all those used in this field, such as, for example, silicones and paraffin oil.
The foam control agents are preferably present in the dishwasher detergent according to the invention in amounts of less than 5% by weight of the total weight of the detergent.
The dishwasher detergents according to the invention may comprise, as bleach, bleaches which are preferably chlorine-free and liberate active oxygen, CA 022~8218 1998-12-16 such as inorganic perhydrates or organic peracids and the salts thereof.
Examples of inorganic perhydrates are perborates, percarbonates and persulfates such as peroxymonopersulfate. The inorganic perhydrates are normally alkali metal salts, such as lithium, sodium, potassium or rubidium salts, in particular sodium salt.
The inorganic perhydrates may be present in the detergent as crystalline solids without further protection. For certain perhydrates, it is however advantageous to use them as granular compositions provided with a coating which gives the granular products a longer shelf life.
The preferred perborate is sodium perborate, which can be in the form of the monohydrate having the formula NaBO2H2O2 or in the form of the tetrahydrate of the formula NaBO2H2O2.3H2O.
The preferred percarbonate is sodium percarbonate of the formula 2Na2CO3.3H2O2- The percarbonate is preferably used for increasing its stability in a coated form.
Organic peracids include all organic peracids traditionally used as bleaches, including, for example, perbenzoic acid and peroxycarboxylic acids such as mono- or diperoxyphthalic acid, 2-octyldiperoxysuccinic acid, diperoxydodecanedicarboxylic acid, diperoxy-azelaic acid and imidoperoxycarboxylic acid and, optionally, the salts thereof.
The dishwasher detergent according to the invention can also comprise one or more bleach activators. These are preferably used in detergents for dishwashing cycles at temperatures in the range below 60~C in order to achieve an adequate bleaching action.
Particularly suitable examples are N- and O-acyl compounds, such as acylated amines, acylated glycolurils or acylated sugar compounds. Preference is given to N,N,N',N'-tetraacetylethylenediamine (TAED), pentaacetylglucose (PAG) and tetraacetylglycoluril (TAGU). Other suitable bleach activators are, however, CA 022~8218 1998-12-16 catalytically active metal complexes and, preferably, transition metal complexes. TAED is most preferable.
Other suitable bleach activators are disclosed in WO 95/01416, to the contents of which express reference is hereby made.
By using MGDA at a relatively low pH, it is, however, possible to reduce the use of bleaches, and the dishwasher detergents according to the invention preferably comprise an oxygen bleach in an amount of less than 1% by weight, based on the active oxygen. The amount of bleach activator used is correspondingly adjusted.
In one embodiment, the dishwasher detergents have a large content of MGDA, such as 25% or more, preferably 30% or more, in each case based on the free acid, and an oxygen bleach is dispensed with.
The dishwasher detergent according to the invention can also comprise a silver/copper corrosion inhibitor. This term encompasses agents which are intended to prevent or reduce the tarnishing of non-ferrous metals, in particular of silver and copper.
Preferred silver/copper corrosion inhibitors are benzotriazole or bis-benzotriazole and substituted derivatives thereof.
Other suitable agents are organic and/or inorganic redox-active substances and paraffin oil.
Benzotriazole derivatives are those compounds in which the available substitution sites on the aromatic ring are partially or completely substituted.
Suitable substituents are linear or branch-chain Cl20-alkyl groups and hydroxyl, thio, phenyl or halogen such as fluorine, chlorine, bromine and iodine. A preferred substituted benzotriazole is tolyltriazole.
Suitable bis-benzotriazoles are those in which the benzotriazole groups are each linked in the 6-position by a group X, where X may be a bond, a straight-chain alkylene group which is optionally substituted by one or more Clg-alkyl groups and preferably has 1-6 carbon atoms, a cycloalkyl radical CA 022~8218 1998-12-16 having at least 5 carbon atoms, a carbonyl group, a sulfuryl group, an oxygen atom or a sulfur atom. The aromatic rings of the bis-benzotriazoles may be substituted as defined above for benzotriazole.
Suitable organic redox-active substances are, for example, ascorbic acid, indole, methionine, an N-mono-(C1-C4-alkyl)glycine, an N,N-di-(Cl-C4-alkyl)glycine, 2-phenylglycine or a coupler and/or developer compound chosen from the group consisting of diaminopyridines,aminohydroxypyridines, dihydroxypyridines, heterocyclic hydrazones, aminohydroxypyrimidines,dihydroxypyrimidines, tetraaminopyrimidines,triaminohydroxypyrimidines, diaminodihydroxypyrimidines, dihydroxynaphthalenes, 15 naphthols, pyrazolones, hydroxyquinolines, aminoquinolines, of primary aromatic amines which, in the ortho-, meta- or paraposition, have another hydroxyl or amino group which is free or substituted by C1-C4-alkyl or C2-C4-hydroxyalkyl groups, and of di- or 20 trihydroxybenzenes.
Suitable inorganic redox-active substances are, for example, metal salts and/or metal complexes chosen from the group consisting of manganese, titanium, zirconium, hafnium, vanadium, cobalt and cerium salts 25 and/or complexes, the metals being in one of the oxidation states II, III, IV, V or VI.
Particularly suitable metal salts and/or metal complexes are chosen from the group consisting of MnSO4, Mn(II) citrate, Mn(II) stearate, Mn(II) acetylacetonate, Mn(II)[1-hydroxyethane-1,1-diphosphonate], V2O5, V2O4, VO2, TioSo4, K2TiF6, K2ZrF6, CoSO4, Co (NO3)2 and Ce(NO3) 3.
Organic and inorganic redox-active substances which are suitable as silver/copper corrosion inhibitors are also mentioned in WO 94/26860 and WO 94/26859, to the contents of which reference is hereby made.
Suitable paraffin oils are predominantly branched aliphatic hydrocarbons having a number of CA 022~82l8 l998-l2-l6 carbon atoms in the range from 20 to 50. Preference is given to the paraffin oil chosen from predominantly branched-chain C25g5 species having a ratio of cyclic to noncyclic hydrocarbons of from 1:10 to 2:1, preferably from 1:5 to 1:1.
If a silver/copper corrosion inhibitor is present in the dishwasher detergent according to the invention, it is preferably present in an amount of from 0.01 to 5% by weight, particularly preferably in an amount of from 0.1 to 2% by weight, of the total weight.
In the embodiment of the invention in which the content of MGDA in the dishwasher detergent is sufficiently high, such as 25% or more, preferably 30%
or more, in each case based on the free acid, with the result that bleach can be omitted, it is also possible to dispense with a silver/copper corrosion inhibitor.
Other customary additives are, for example, dyes and perfumes and optionally in the case of liquid products, preservatives, suitable examples of which are compounds based on isothiazolinone.
The dishwasher detergents according to the invention are not caustic and therefore do not require particularly secured packaging. A good detergency can be achieved using a relatively low use amount of 15-20 g of powder or 20-50 ml of liquid detergent.
According to current knowledge, none of the ingredients is either toxic or detrimental to health in any other way. The detergents described here thus also represent an environment- and consumer-friendly alternative to conventional detergents containing complexing agents which are effective in the strongly basic range.
The methylglycinediacetic acid used according to the invention has the following structural formula:
HO2C ~ _<CH3 HO2C-- CC~2H
CA 022~8218 1998-12-16 The methylglycinediacetic acid is particularly preferably used as the free acid or as the sodium or potassium salt, and is preferably present in the dishwashing detergent in an amount of from 3% to 90%, based on the free acid.
In bleach-free dishwasher detergents which are based on phosphates as the principal constituent of the builder system, the amount of MGDA is preferably at least 5%, based on the free acid.
According to the invention, it is essential that an approximately 0.5% strength aqueous solution of the detergent has a pH of no more than 10.4. The pH of an approximately 0.5% strength aqueous solution of the detergent according to the invention is preferably from more than 6 to 10.4, particularly preferably from 7 to 10 . O .
The following comparative experiment demonstrates that the dishwashing detergents proposed in the article in the SOFW Journal 122, 1996, 392-397, have in 0.5% strength aqueous solutions, a pH of more than 10.4. The disclosure of this article is therefore in agreement with the theoretical expectation that MGDA
is an excellent complexing agent at a pH of more than 10.4, but is inferior to the traditional NTA at a pH of 10.4 or below.
Comparative Experiment 30 In agreement with the disclosure of the article in the SOFW Journal 122, 1996, 392-397, dishwashing detergents are prepared from the following constituents:
Sodium citrate dihydrate Sodium carbonate Sodium hydrogen carbonate Sodium perborate monohydrate TAED
CA 022~82l8 l998-l2-l6 C13-C1s-OxO alcohol + 4 mol of PO + 2 mol of EO
MGDA (trisodium salt of methylglycinediacetic acid) (77% strength solution in water) = TRILON ES 9964 obtainable from BASF AG.
The table below shows the amounts of the respective constituents in g and %. The constituents were dissolved in one litre of water having a hardness of 10~, and the pH of the solution was determined in each case. The total amount of the constituents (100%) 10 is in each case 4 g, corresponding to a 0. 4% strength concentration, as is disclosed in Figure 14 of the article.
MGDA in pure form is not available commercially, and therefore a 77% strength solution in water was used. A relatively large amount of the commercially available product therefore had to be used, as the Table shows. For MGDA, the Table gives two values in each case. The first value is the amount in g of the commercial product, and the second value 20 corresponds to the corresponding amount of pure substance (100%).
SOFW Journal 122, 1996, 392-397 Example 1 Example 2 Example 3 Amounts in g (%' Citrate 2 (50%) 1.6 (40%) 1 (25%) Carbonate 1 (25%) 1 (25%) 1 (25%) Hydrogen-carbonate 0.36 (9%) 0.36 (9%) 0.36 (9%) Perborate 0.28 (7%) 0.28 (7%) 0.28 (7%) TAED 0.08 (2%) 0.08 (2%) 0.08 (2%) Nonionic 0. 08 (2%) 0.08 (2%) 0.08 (2%) surfactant MGDA 0.26/0.2 (5%) 0.78/0.6 (15%) 1.56/1.2 (30%) (77% solu-tion)/(100%) Total 4.06 4 4.18 4 4.36 4 ¦pH ¦10. 64 ¦ 10.79 ¦ 10.82 CA 022~8218 1998-12-16 Although the pH of 0.5% strength solutions of the agents was not determined directly, the pH of 0.4%
strength solutions was determined. At a higher concentration of the detergent, the solutions of the detergent will obviously have the same or, more probably, a higher pH.
The example below shows that when some of the builder of a dishwasher detergent is replaced by methylglycinediacetic acid, at a low pH, excellent detergency can be achieved and, in particular, contrary to the theoretical expectations, the ability to remove milk residues and tea residues is greater than in the case of other traditional complexing agents such as NTA. The example illustrates the invention.
ExA~nple Liquid dishwashing detergents having a composition as given in Table 1 were prepared (both in accordance with the invention using MGDA and using the NTA customary in the prior art), and their detergency was determined using dishes soiled with both milk and tea residues. In this experiment, the DIN Standard No. 44990, Part 2 was essentially followed. A Bosch SMS 5062 dishwasher was used. The water had a hardness of 19~ German hardness (3.39 mmol of calcium carbonate), the temperature of the water was 65~C and 20 ml of detergent were used in each case. The detergency results were evaluated on a scale from 1 to 5 (where 5 is 100% clean dishes) and are also given in Table 1.
The nonionic surfactant is a customary, low-foaming ethoxylated and propoxylated fatty alcohol.
Customary proteases and amylases are used.
CA 022~82l8 l998-l2-l6 Table 1 NTA I MGDA I NTA II MGDA NTA MGDA
II III III
Water 1.47 0.00 3.57 0.57 7.67 3.77 Citric acid 8.00 9.47 5.90 8.90 1.80 5.70 MGDA (35.6%) 0.00 87.1 0.00 87.1 0.00 87.1 NTA (35.6%) 87.1 0.00 87.1 0.00 87.1 0.00 Nonionic 1.50 1.50 1.50 1.50 1.50 1.50 surfactants Protease 0.50 0.50 0.50 0.50 0.50 0.50 Amylase 0.50 0.50 0.50 0.50 0.50 0.50 Preservative 0.03 0.03 0.03 0.03 0.03 0.03 Perfume 0.10 0.10 0.10 0.10 0.10 0.10 Thickener 0.80 0.80 0.80 0.80 0.80 0.80 ioo loo loo loo loo loo pH (0.5% 8.1 8.0 9.4 9.3 10.4 10.3 strength) Tea 4.2 4.7 4.4 4.8 4.6 5.0 Milk 3.1 3.3 3.2 3.3 3.0 3.4 The results in Table 1 show that in a pH range below 10. 4 detergents which comprise MGDA achieve surprisingly better results both in the removal of milk residues and in the removal of tea residues than the corresponding detergents which comprise the customary NTA instead of MGDA.
Claims (4)
1. A dishwasher detergent comprising methylglycinediacetic acid or salts thereof as complexing agent, wherein the composition, in about 0.5% strength aqueous solution, does not exceed a pH of 10.4.
2. The dishwasher detergent as claimed in claim 1 which comprises an oxygen bleach in an amount of less than 1% based on the weight of active oxygen.
3. The dishwasher detergent as claimed in claim 1 or 2, wherein the composition, in about 0.5% strength aqueous solution, has a pH of from 6 to 10.4.
4. The use of methylglycinediacetic acid or salts thereof as the complete or partial replacement for builders or complexing agents in dishwasher detergents with a pH of no more than 10.4 in about 0.5% strength aqueous solution to improve its ability to remove milk residues and also tea residues.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19624839 | 1996-06-21 | ||
| DE19624839.6 | 1996-06-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2258218A1 true CA2258218A1 (en) | 1997-12-31 |
Family
ID=7797614
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002258218A Abandoned CA2258218A1 (en) | 1996-06-21 | 1997-06-20 | Low-alkaline mgda-containing dishwasher rinsing agent |
Country Status (6)
| Country | Link |
|---|---|
| EP (2) | EP1113070B1 (en) |
| AT (2) | ATE205250T1 (en) |
| CA (1) | CA2258218A1 (en) |
| DE (2) | DE59704543D1 (en) |
| ES (2) | ES2300287T3 (en) |
| WO (1) | WO1997049792A1 (en) |
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| US8709990B2 (en) | 2011-10-19 | 2014-04-29 | Basf Se | Formulations, their use as or for producing dishwashing detergents and their production |
| CN103146506A (en) * | 2013-03-05 | 2013-06-12 | 广州立白企业集团有限公司 | Dish washing detergent composition with tea stain cleaning effect |
| DE102013214780A1 (en) * | 2013-07-29 | 2015-01-29 | Henkel Ag & Co. Kgaa | Care products for automatic dishwashers |
| DE102013019269A1 (en) | 2013-11-15 | 2015-06-03 | Weylchem Switzerland Ag | Dishwashing detergent and its use |
| EP3228686B1 (en) | 2016-04-08 | 2021-10-27 | The Procter & Gamble Company | Automatic dishwashing |
| DE102016212248A1 (en) | 2016-07-05 | 2018-01-11 | Henkel Ag & Co. Kgaa | Dishwashing detergent containing sugar acid and aminocarboxylic acid |
| EP3623456A1 (en) | 2018-09-12 | 2020-03-18 | CLARO Products GmbH | Silver protection agent |
| DE102019219812A1 (en) * | 2019-12-17 | 2021-06-17 | Henkel Ag & Co. Kgaa | Agent for machine dishwashing with improved cleaning performance for bleachable soiling |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4036695C2 (en) * | 1990-11-17 | 1994-08-25 | Henkel Kgaa | Use of beta-alanine derivatives as builders in phosphate-free dishwashing detergents |
| JPH05105900A (en) * | 1991-08-27 | 1993-04-27 | Kao Corp | Cleaning agent for cleaning apparatus |
| DE4319798A1 (en) * | 1993-06-15 | 1994-12-22 | Henkel Kgaa | Dishwashing detergent with reduced tendency to scale up |
| DE4319935A1 (en) * | 1993-06-16 | 1994-12-22 | Basf Ag | Use of glycine-N, N-diacetic acid derivatives as complexing agents for alkaline earth and heavy metal ions |
| US5481018A (en) * | 1995-03-31 | 1996-01-02 | The Dow Chemical Company | Amino nitrile intermediate for the preparation of alanine diacetic acid |
| GB2311536A (en) * | 1996-03-29 | 1997-10-01 | Procter & Gamble | Dishwashing and laundry detergents |
-
1997
- 1997-06-20 EP EP01105118A patent/EP1113070B1/en not_active Revoked
- 1997-06-20 AT AT97928266T patent/ATE205250T1/en not_active IP Right Cessation
- 1997-06-20 ES ES01105118T patent/ES2300287T3/en not_active Expired - Lifetime
- 1997-06-20 DE DE59704543T patent/DE59704543D1/en not_active Expired - Fee Related
- 1997-06-20 WO PCT/EP1997/003256 patent/WO1997049792A1/en not_active Application Discontinuation
- 1997-06-20 CA CA002258218A patent/CA2258218A1/en not_active Abandoned
- 1997-06-20 AT AT01105118T patent/ATE389709T1/en not_active IP Right Cessation
- 1997-06-20 EP EP97928266A patent/EP0906407B1/en not_active Revoked
- 1997-06-20 ES ES97928266T patent/ES2160355T3/en not_active Expired - Lifetime
- 1997-06-20 DE DE59712930T patent/DE59712930D1/en not_active Expired - Lifetime
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8193139B2 (en) | 2005-08-31 | 2012-06-05 | Basf Aktiengesellschaft | Cleaning formulations for machine dishwashing comprising hydrophilically modified polycarboxylates |
| EP1924675B2 (en) † | 2005-08-31 | 2015-07-29 | Basf Se | Cleaning formulations for machine dishwashing comprising hydrophilically modified polycarboxylates |
| EP2261313B1 (en) | 2005-11-07 | 2018-01-03 | Reckitt Benckiser Finish B.V. | Composition |
| US7879154B2 (en) | 2007-02-06 | 2011-02-01 | Henkel Ag & Co. Kgaa | Phosphate-free dishwashing detergents comprising builder, bleaching agent, nonionic surfactant, copolymer and a phosphonate |
| US8303721B2 (en) | 2007-02-06 | 2012-11-06 | Henkel Ag & Co. Kgaa | Detergent comprising a builder, a bleaching agent, and a copolymer |
| US9752100B2 (en) | 2007-02-06 | 2017-09-05 | Henkel Ag & Co. Kgaa | Detergents |
| TWI600755B (en) * | 2012-07-27 | 2017-10-01 | Kao Corp | Dishwashing detergent composition |
| WO2014206781A1 (en) * | 2013-06-25 | 2014-12-31 | Unilever N.V. | Hygroscopic detergent formulation comprising water, aminocarboxylate chelant and moisture-sensitive ingredients |
| EP2821471A1 (en) * | 2013-07-02 | 2015-01-07 | Basf Se | Aqueous solutions containing a complexing agent in high concentration |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0906407A1 (en) | 1999-04-07 |
| WO1997049792A1 (en) | 1997-12-31 |
| ES2160355T3 (en) | 2001-11-01 |
| EP1113070B1 (en) | 2008-03-19 |
| EP0906407B1 (en) | 2001-09-05 |
| ATE389709T1 (en) | 2008-04-15 |
| ES2300287T3 (en) | 2008-06-16 |
| DE59704543D1 (en) | 2001-10-11 |
| EP1113070A3 (en) | 2002-01-02 |
| ATE205250T1 (en) | 2001-09-15 |
| DE59712930D1 (en) | 2008-04-30 |
| EP1113070A2 (en) | 2001-07-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |