DE69319158T2 - Detergent composition - Google Patents

Description

Field of the invention

The present invention relates to an aqueous liquid detergent product which is particularly designed for use in a dishwasher.

Background and state of the art

Liquid dishwasher detergents, both aqueous and non-aqueous, have received much attention recently and the aqueous products have achieved commercial popularity.

The acceptance and popularity of liquid preparations compared to the more common powdered products is due to the convenience and performance of the liquid products. However, the currently available and proposed liquid product preparations are based on the concept of the common powder compositions for dishwashers, which are highly alkaline products with a high proportion of builders containing a chlorine bleach (see e.g. EP-A 0 517 308 and EP-A 517 309).

FR-A 2 355 908 relates to chlorine-free dishwasher compositions comprising a non-ionic surfactant and an enzyme mixture. EP-A 429 124 relates to chlorine-free dishwasher compositions in which silicate is applied to provide alkalinity and storage stability.

It has now surprisingly been found that a mild and still very effective aqueous liquid cleaning composition for dishwashers can be formulated based on certain surfactants and proteolytic enzymes, whereby a obvious synergistic effect occurs between the active ingredient and the protease enzyme, especially in the removal of protein contaminants.

The use of glycosides in detergent compositions has been disclosed in a number of documents. WO-A 86/05187 (Staley) discloses detergent compositions comprising glycoside surfactant and enzyme. Various enzymes are mentioned.

DE-A 3 833 047 discloses acidic powdered dishwasher compositions containing alkyl glycoside in combination with other surfactants and amylase. These compositions are acidic and have a solution pH below 6.

Summary of the invention

According to the invention there is provided an aqueous liquid dishwasher cleaning composition which is free from chlorine bleach and which:

(a) 0.0002 to 0.05 Anson units per gram composition of a proteolytic enzyme;

(b) 5 to 90% by weight of a detergent builder;

(c) 1 to 40 wt.% sodium or potassium silicate having a ratio of SiO₂:Na₂O or SiO₂:K₂O of 2.0 to 3.2;

(d) 3 to 50% by weight of an organic surfactant selected from the group

(i) Glycoside surfactants;

(ii) anionic surfactants having a hydrophilic head group which is or contains a sulfate or sulfonate group and having a hydrophobic A moiety which is or contains an alkyl or alkenyl group having 8 to 22 carbon atoms;

(iii) ethoxylated fatty alcohols of the formula RO(CH₂CH₂O)nM, wherein R is an alkyl group having 6 to 16 carbon atoms and n has an average value which is at least 4 and is sufficiently high that the HLB value of the ethoxylated fatty alcohol is 10.5 or greater, with the proviso that when the ethoxylated fatty alcohol (iii) is used without anionic surfactant (ii), the majority of the alkyl groups R contain 6 to 12 carbon atoms and

(iv) mixtures thereof;

(e) water, wherein the composition has a pH of 7 to 11 when added to deionized water at a concentration of 2 g/l.

According to a second aspect, the invention provides a method of washing dishes and/or glassware comprising exposing the dishes and/or glassware to a mixture of water and a cleaning composition as specified above. According to a further aspect, the invention provides the use of such a composition in a dishwasher.

Detailed description The proteolytic enzyme

A protease is used in an amount ranging from 0.0002 to 0.05 Anson units/g of cleaning composition, preferably 0.001 to 0.025 Anson units. Expressed in other units, the protease in the compositions can be Amounts in the order of 0.5 to 100 GU/mg of the cleaning composition may be present. Preferably, the amount is in the range of 1 to 50 and particularly preferably 2 or even 5 to 15 or 20 GU/mg of the composition.

One GU is one glycine unit, defined as the proteolytic enzyme activity that under standard conditions produces an amount of NH2 groups equivalent to 1 µmol of glycine during a 15-minute incubation at 40ºC with N-acetylcasein as substrate.

Enzyme activities are sometimes also measured in kib-Nove units (KNPU): a measurement dependent on the type of protease and the assay used. The KNPU/AU ratio has been found to be in the range of about 3:1 to 5:1 for Alcalase, Esperase and Savinase and for the present preparations it is not necessary to be more precise.

Preferred examples of a protease enzyme that can be used for the present compositions are subtilisin types sold as Savinase (trademark of Novo-Nordisk A/S) or Maxacal (trademark of Gist/Brocades/IBIS) or as Opticlean (from MKC) or AP122 (from Showa Denko), whose pI is approximately 10. Other suitable examples of proteases include Maxatase, Esperase, Alcalase (trademark), Protinase K and Subtilisin BPN'. Protinase K can also be used.

Organic surfactant Glycoside surfactant

This is non-ionic and naturally contains glycoside residues. Suitably, it has the general formula:

wherein G is a residue of a pentose or hexose, R'O is an alkoxy group, x is at least one moiety and R is an organic hydrophobic group which is preferably an aliphatic, saturated or unsaturated, especially straight-chain or branched alkyl, alkenyl, hydroxyalkyl or hydroxyalkenyl residue. However, the residue may also include an aryl group, e.g. an alkylaryl, alkenylaryl and hydroxyalkylaryl group. It is envisaged that R may have 6 to 20 carbon atoms.

It is particularly preferred that R is an alkyl or alkenyl radical having 7 to 14 or 16 carbon atoms, in particular 7 to 12 carbon atoms.

The value of t in the general formula above is preferably 0 so that the -(R'O)t unit of the general formula is not present. In this case, the general formula becomes:

If t is not 0, it is preferred that R'O is an ethylene oxide residue. Other possibilities are propylene oxide and glycerol residues. If the parameter t is not 0, so that R'O is present, the value for t (which may be an average value) is preferably in the range of 0.5 to 10.

The group G typically comes from fructose, glucose, mannose, galactose, talose, gulose, allose, altrose, idose, arabinose, xylose, lyxose and/or ribose. Preferably, G is supplied essentially exclusively by glucose units. Intersaccharide bonds can be from position 1 to position 2, 3, 4 or 6 of the adjacent saccharide. Hydroxyl groups on sugar residues can be substituted, e.g. etherified with short alkyl chains with 1 to 4 carbon atoms. Preferably, a sugar residue does not carry more than one such substituent.

The value x, which is an average value, is usually referred to as the degree of polymerization. Desirably, x is between 1 and 8. Values for x may be between 1 and 3, especially 1 and 1.8.

Alkyl polyglycosides of the formula RO(G)x, i.e. a formula as given above, where t is 0, are available from BASF and Henkel.

Alkyl polyglycosides of particular interest have a value for x in a narrow range, from 1 or 1.2 up to 1.4 or especially 1.3. When x exceeds 1.3, it is preferably in the range from 1.4 to 1.8.

When x is in the range of 1 to 1.4, it is preferred that R is C8-C14 alkyl or alkenyl.

O-alkanoylglucosides are described in the international patent application WO 88/10147 (Novo Industri A/S). The surfactants specifically described therein are glucose esters in which the acyl group is bonded in position 3 or 6, e.g. 3-O-acyl-D-glucose or 6-O-acyl-D-glucose. Noteworthy are 6-O-alkanoylglucosides in which the alkanoyl group contains an alkyl or alkenyl group with 7 to 13, preferably 7, 9 or 11 carbon atoms. The glucose residue can be alkylated at position 1 with an alkyl group with 1 to 4 carbon atoms, e.g. an ethyl or isopropyl group. The alkylation at position 1 enables such compounds to be prepared by regiospecific enzymatic synthesis, as described by Bjorkling et al. (J. Chem. Soc., Chem. Commun. 1989, page 934).

Although esters of glucose are particularly considered, it is expected that other corresponding materials based on other reducing sugars, such as galactose and mannose, are also suitable.

Anionic surfactant

Preferred anionic surfactants are the following or a mixture thereof:

primary alkyl sulfate of the formula:

R¹OSO₃M

wherein R¹ is a primary alkyl group having 8 to 18 carbon atoms and M is a solubilizing cation,

Fatty acid ester sulfonate of the formula:

wherein R² is an alkyl group having 6 to 16 carbon atoms, R³ is an alkyl group having 1 to 4 carbon atoms and M is a solubilizing cation,

Alkylbenzenesulfonate of the formula:

wherein R⁴ is an alkyl group having 10 to 16 carbon atoms and M is a solubilizing cation,

Alkyl ether sulfate of the formula:

R¹O (CH₂CH₂O)nSO₃M wherein R¹ is a primary alkyl group having 8 to 18 carbon atoms, n has an average value in the range of 1 to 6 and M is a solubilizing cation.

A primary alkyl sulfate is particularly preferred as a surfactant. In the general formula

R¹SO₃M

the solubilizing cation can be any cation that is generally monovalent and contributes to water solubility. Alkali metals, particularly sodium, are specifically considered. Other possibilities are ammonium and substituted ammonium, e.g. trialkanolammonium.

The alkyl group R¹ can have a mixture of chain lengths. It is preferred that at least two thirds of the alkyl groups R¹ have a chain length of 8 to 14 carbon atoms. This is the case, for example, when R¹ is a coconut alkyl group.

When the surfactant is a fatty acid ester sulfonate, alkylbenzenesulfonate or alkyl ether sulfonate, the solubilizing cation M can be any cation as discussed above for alkyl sulfate.

In the general formula for the fatty acid ester sulfonate:

the group R² can have a mixture of chain lengths. Preferably, at least two thirds of these groups have 6 to 12 carbon atoms. This is the case if the rest:

e.g. from coconuts.

The group R³ may be any C₁-C₄ alkyl group. Straight chain alkyl groups may be preferred, especially methyl and ethyl groups.

In the general formula for the alkylbenzenesulfonate:

the group R⁴ can have a mixture of chain lengths. Straight chains with 11 to 14 carbon atoms are preferred.

In the general formula for the alkyl ether sulfate:

R¹O(CH₂CH₂O)nSO₅M

is the group R¹ as discussed for the alkyl sulfate. Preferably n has an average value of 2 to 5.

Non-ionic surfactant

The ethoxylated fatty alcohol can be used alone or in admixture with anionic surfactants, particularly with the preferred surfactants above. However, when used alone, the fatty alcohol must have a limited chain length, so that the average chain length of the alkyl group R in the general formula:

RO(CH₂CH₂O)nH

6 to 12 carbon atoms. This is preferred in any case and it is particularly preferred if the weight of the anionic surfactant is less than half the weight of the ethoxylated fatty alcohol.

In particular, the group R can have chain lengths in a range of 9 to 11 carbon atoms.

An ethoxylated fatty alcohol is normally a mixture of molecules with a different number of ethylene oxide residues. Their average number n together with the alkyl chain length determines whether the ethoxylated fatty alcohol has a hydrophobic character (low HLB value) or a hydrophilic character (high HLB value). For the invention the HLB value should be 10.5 or greater. This requires that the average value for n is at least 4 and preferably higher. The number of ethylene oxide residues may be a statistical distribution around the average value. However, as is known, the distribution may be influenced by the manufacturing process or changed by fractionation after ethoxylation.

Particularly preferred ethoxylated fatty alcohols have a group R having 9 to 11 carbon atoms, while n is 5 to 8.

Other surfactants

The above surfactant, or a mixture of two or more of them, may possibly be accompanied by some other surface-active agent, usually in a minor amount. Preferably, the amount of any other surface-active agent is not more than one third of the total weight of the surface-active agent present, or even not more than one quarter.

If another surfactant is included, it may be anionic or nonionic, or possibly amphoteric or zwitterionic. A cationic surfactant is possible if an anionic is not present, but it is not preferred. Soap may optionally be included, as may non-soap surfactants.

One important possibility is the use of a surfactant or a mixture of surfactants of the above-mentioned anionic and/or non-ionic types, together with glycoside surfactants of the above-mentioned type.

As mentioned, the amount of glycoside surfactant, anionic surfactant and/or ethoxylated fatty alcohol surfactant is 3 to 50 wt% of the composition. Desirably, the total amount of surfactant is in the same range. Preferred ranges, both for the specific surfactant and for all surfactants, are 3 to 30 wt%, more preferably in the range of 5 or 10 to 25 wt%.

Detergent scaffold materials

The cleaning compositions of the invention may contain all types of detergent builders generally taught for use in dishwashers or other cleaning compositions. The builders may contain the usual inorganic and organic water-soluble builder salts and also insoluble inorganic builders or mixtures thereof and constitute from 5 to 90% by weight of the cleaning composition.

Typical well-known inorganic builders are sodium and potassium salts of the following compounds: pyrophosphate, tripolyphosphate, ortho-phosphate, carbonate, bicarbonate, sesquicarbonate and borate. Other non-phosphorus salts including (insoluble) crystalline and amorphous aluminosilicates (e.g. zeolites) can also be used.

Preferred builders may be selected from the group consisting of sodium tripolyphosphate, sodium carbonate, sodium bicarbonate and mixtures thereof. When sodium tripolyphosphate is present in these compositions, the concentration is usually in the range of 2 to 40, preferably 5 to 30. Sodium carbonate and bicarbonate, if present, may be in the range of 10 to 50%, preferably 20 to 40% by weight. of the cleaning composition. Potassium pyrophosphate is a preferred builder in gel preparations, where it can be used at 3 to 30%, preferably 10 to 20%.

Organic detergent builders can also be used in the present invention. They are generally sodium and potassium salts of the following compounds: citrate, malonate or succinate substituted with a C6-C24 alkyl group, nitrilotriacetates, phytates, polyphosphonates, oxydisuccinates, oxydiacetates, carboxymethyloxysuccinates, tetracarboxylates, starch, oxidized heteropolymeric polysaccharides and polymeric polycarboxylates such as polyacrylates having a molecular weight of from about 5,000 to about 200,000. Polyacetal carboxylates such as those described in U.S. Patent No. 4,144,226 and U.S. Patent No. 4,146,495 can also be used. Non-phosphate builders are particularly preferred for environmental reasons.

Sodium citrate is a particularly preferred builder. When present, it is preferably used in an amount of from 1 to 75% of the total weight of the cleaning composition, especially from 10 to 50% by weight.

The foregoing detergent builders are intended to illustrate, but not limit, the types of builders that can be used in the present invention.

silicate

The compositions of the invention contain sodium or potassium silicate in a proportion of 1 to 40% by weight of the cleaning composition, more preferably 5 to 25%, even more preferably 7 to 20%. This material is used as a cleaning ingredient, Source of alkalinity, metal corrosion inhibitor and glaze protectant for tableware. The sodium or potassium silicate used here has a SiO:Na₂O or SiO₂:K₂O ratio of 2.0 to 3.2. Part of the silicate may be in solid form. Sodium silicate with a SiO₂:Na₂O ratio of more than 2.0, preferably at least 2.4, is suitable.

When a composition contains less than 10% silicate, it is preferred to add a zinc salt such as zinc sulphate, particularly when the composition gives an alkaline pH when dissolved, e.g. a pH of more than 8.5. A zinc salt serves to protect glassware from attack by alkaline wash liquors and may suitably be applied in amounts of from 0.1 to 3% by weight.

Other optional ingredients Bleaching system

Compositions according to the invention are free from chlorine bleaching compounds, but may contain a peroxygen bleaching component. If present, the amount thereof is preferably in a range of 1 to 30% by weight.

A peroxygen bleach that can be used is, for example, sodium perborate. This is preferably accompanied by a bleach activator that allows the release of active oxygen species at lower temperature. A preferred bleach activator is tetraacetylethylenediamine (TAED), but other activators for perborate are known and can be used. The amounts of peroxygen bleach and Bleach activator in a single composition preferably does not exceed 20 or 15 wt.%.

Another peroxygen bleach is sodium percarbonate. Another is sodium monopersulfate. Other peroxygen bleaches that can be used are organic alkyl, alkenyl and aryl peroxy acids and their metal salts. Typical peroxy acids include

(i) Peroxybenzoic acid and ring-substituted peroxybenzoic acids, e.g. peroxy-α-naphthoic acid

(ii) aliphatic and substituted aliphatic monoperoxyacids, e.g. peroxylauric acid and peroxystearic acid

(iii) 1,12-diperoxydodecanedioic acid (DPDA)

(iv) 1,9-diperoxyazelaic acid

(v) Diperoxybrassylic acid; diperoxysebacic acid and diperoxyisophthalic acid

(vi) 2-Decyldiperoxybutane-1,4-dioic acid

(vii) Phthaloylamidoperoxycaproic acid (PAP).

Thickeners and stabilizers

Thickeners are often desirable for liquid cleaning compositions. Thixotropic thickeners such as smectite clays including montmorillonite (bentonite), hectorite, saponite and the like can be used to impart viscosity to the liquid cleaning composition. Silica, silica gel and aluminosilicate can also be used as thickeners. The use of clay thickeners for dishwashing compositions is disclosed, for example, in US Patent Nos. 4,431,559, 4,511,487, 4,740,327, 4,752,409. The use of salts of polymeric carboxylic acids is disclosed, for example, in patent application GB-A 2 164 350. Commercially available bentonite clays include Korthix H and VWH from Combustion Engineering Inc.; Polargel T from American Colloid Co.; and Gelwhite clays (particularly Gelwhite GP and H) from English China Clay Co. Polargel T is preferred because it imparts a more intense white appearance to the composition than other clays.

Various polymers may be included. These may in particular promote detergent builder formation or be polymeric thickeners which may be used alone or together with other types of thickeners. Notable are polymers containing carboxylic acid or sulfonic acid groups in acidic form or fully or partially neutralized as sodium or potassium salts, the sodium salts being preferred. Preferred polymers are homopolymers and copolymers of acrylic acid and/or maleic acid or maleic anhydride. Of particular interest are polyacrylates, poly-α-hydroxyacrylates, acrylic/maleic acid copolymers and acrylic acid phosphinates. Other polymers which are particularly preferred for use in liquid cleaning compositions are deflocculating polymers, for example as disclosed in EP-A 346 995.

The molecular weights of homopolymers and copolymers are generally between 1000 and 150,000, preferably 1500 and 100,000. Polyacrylate thickeners can also have molecular weights of 300,000 up to 6 million. The amount of any polymer can range from 0.5 to 5% or even 10% by weight of the composition.

For liquid preparations with the appearance and rheology of a "gel", especially when a clear gel is desired, a chlorine-stable polymeric thickener is particularly useful. U.S. Patent No. 4,260,528 discloses natural gums and resins for use in clear dish detergents which are not chlorine stable. Crosslinked acrylic acid polymers manufactured by BF Goodrich and sold under the trademark "Carbopol" have been found to be effective in making clear gels and Carbopol 940 having a molecular weight of about 4 million is particularly preferred for maintaining high viscosity with excellent chlorine stability over long periods of time. Other suitable chlorine stable polymeric thickeners are described in U.S. Patent No. 4,867,896.

The amount of thickener, including any polymeric thickeners, employed in the composition may be in the range of 0 to 5%, preferably 1 to 3%.

Stabilizers and/or co-structurants such as long chain calcium and sodium soaps and C12-C18 alkyl sulfates are described in detail in U.S. Patent Nos. 3,956,158 and 4,271,030, and the use of other metal salts of long chain soaps is detailed in U.S. Patent No. 4,752,409. The amount of stabilizer that can be used in liquid cleaning compositions is from 0.01% to about 5% by weight of the composition, preferably 0.1% to 2%. Such stabilizers are optional for gel preparations. Co-structuring agents which have been found to be particularly suitable for gels include trivalent metal ions at 0.01 to 4% of the composition and/or water-soluble structure-forming complexing agents at 1 to 60%. These co-structuring agents are fully described in EP-A 323 209.

Defoamers

An important consideration in dishwasher compositions is the need to suppress foaming. The agitation conditions in a dishwasher are more vigorous than those in a washing machine and lead to foaming. Some food residues, such as egg and cream, also lead to the generation of foam.

Foam, when it forms, can cause air to be drawn into the circulation pump. This can interfere with proper water circulation and the delivery of water to the heating element. Excessive foam generation can potentially cause an air trap in the pump, which could destroy the machine by stopping the water supply to the heating element.

A composition according to the invention can further contain defoaming agents. Even if the cleaning composition contains only a low foaming surfactant, the presence of a defoaming agent can serve to minimize foam that food soils can generate.

Current dishwasher compositions contain a non-ionic surfactant containing ethylene oxide and propylene oxide residues. These surfactants have cloud points below the operating temperature and therefore they form hydrophobic droplets that exert an antifoam effect.

Materials that can be used as defoamers in a composition according to the invention include mono- and di-C₈-C₂₂-alkyl phosphates and mineral oil/or wax. These can be used as a combination containing particles of the insoluble alkyl phosphate with petrolatum. Possible alternatives to the alkyl phosphate include ethylene distearamide, Calcium soap and finely divided silica, particularly hydrophobized silica. Mineral oils and waxes which may be used include petroleum fractions, Fischer-Tropsch waxes, ozokerite, ceresin montan wax, beeswax, candelilla wax, carnauba wax and mixtures thereof.

Another category of materials that can be used are ketones of the formula R7COR8, where R7 and R8 are each alkyl or alkenyl groups having 8 to 24 carbon atoms, such that the ketone contains 25 to 49 carbon atoms. Ketones of this type and their use as antifoaming agents in (other) dishwasher compositions are disclosed in EP-A 324 339.

Another category of materials that can be used as a defoamer is soap or fatty acid which is neutralized to soap when used in the composition. Such a soap or fatty acid should have an acyl group having 12 to 22 carbon atoms, especially 14 to 18 carbon atoms. When soap or fatty acid is used as a defoamer, some calcium salt may be intentionally included in the composition, thereby ensuring the presence of calcium ions to form a calcium soap having the defoaming effect.

The composition may contain the defoamer, which is preferably a compound other than a nonionic surfactant, if present, in a proportion of 0.1 to 30% by weight. Non-soap defoamers may be used in proportions towards the lower end of this range, eg 0.1 to 10%, preferably 0.5 to 2 or 5%. Soap or fatty acid may be used as a defoamer and, if present, in amounts of 0.1 to 30% by weight, in particular 0.5 to 10%.

When the surfactant is alkyl sulfate alone, it may be desirable to use a ketone (in a branched chain alcohol), soap or fatty acid as a defoamer to avoid alkyl phosphates or mineral oil.

Minor amounts of various other components may be present in the cleaning composition. These include antiscalants, corrosion inhibitors, soil carriers, antitarnish agents, other enzymes (particularly amylase and/or lipase at 0.05 to 2% by weight, preferably 0.5 to 1.5%) and other functional additives and perfume.

As indicated above, the compositions of the invention may be in the form of a liquid or a gel.

The composition is formulated to give a pH in the range of 7 to 11, more preferably 8 to 11, when added to deionized water at a concentration of 2.0 g/l. A particularly preferred pH is 9.0 to 9.5.

The following examples further illustrate embodiments of the invention. All parts, percentages and proportions referred to herein and in the appended claims are by weight unless otherwise specified.

example 1

This example shows the effect of removing dirt from glass slides.

New glass slides, 5 cm x 5 cm, were machine-washed, repeatedly rinsed with demineralized water, and soiled with approximately 55 mg of baked egg yolk per slide.

All washing solutions contained, in 1 l of water with a French hardness of 16º:

Sodium citrate dihydrate 0.445 g

Acrylic acid-maleic acid copolymer (Sokolan+ CP5) 0.111 g

Sodium disilicate monohydrate* 0.445 g

Potassium coconut soap 0.100 g

Sodium sulfate dihydrate 0.950 g

Calcium sulfate 0.03 g

(+ trademark)

*SiO2:Na2O > 2.0

These materials were added to the water and stirred at 45ºC for 15 minutes. To some solutions was then added:

30 mg Savinase 6.0 CM (sold at 1500 GU/mg, analyzed at 1544 GU/mg) and/or

0.5 g of alkyl polyglycoside of the formula RO(G)x, where R = C₁₂-C₁₄-alkyl radical, G denotes a glucose radical and x has an average value of 1.3.

The solutions were kept at 45ºC.

After one minute, the slides were placed in the solution. The slides were removed after various periods of time, dried and weighed to determine the amount of soil removed. The amount removed was expressed as a percentage of the original soil. The results were as follows:

These results demonstrate a synergistic improvement in soil removal by using APG together with the proteolytic enzyme at wash times of 10 minutes or more.

Example 2

The procedure was as in Example 1. All solutions contained, per liter of water:

Sodium citrate dihydrate 0.60 g

Acrylic acid-maleic acid copolymer 0.15 g

Sodium disilicate monohydrate 0.60 g

To some solutions 0.5 g of alkyl polyglycoside and/or 30 mg of savinase (both as used in Example 1) were added. To other solutions 0.5 g of C13-C15 alcohol 3EO (Synperonic+A3) and/or 30 mg of savinase were added. The supports were left in the solution for 60 minutes at 45°C.

The results were:

(+ trademark)

The synergy with APG clearly exceeded the synergy (if any) with Synperonic A3.

Example 3

The procedure was as in Example 2. All solutions contained in 1 l of water:

Sodium tripolyphosphate 1.16 g

Sodium carbonate 0.27 g

Sodium disilicate hydrate 0.32 g

To some solutions, 0.5 g of alkyl polyglycoside and/or 30 mg of Savinase (each as used in Example 1) was added.

To further solutions were added 0.5 g of C₁₃-C₁₅ alcohol 3EO (Synperonic A3) and/or 30 mg of Savinase. The slides were left in the solution at 45ºC for 60 minutes. The results were:

Again, APG plus Savinase provided the best soil removal.

Example 4

The procedure was as in Example 14. Different types of alkyl polyglycosides were used. All solutions contained per liter of water:

Sodium citrate dihydrate 0.60 g

Acrylic acid-maleic acid copolymer 0.15 g

Sodium disilicate monohydrate 0.60 g

Alcalase 2.0T 30 mg (which gives an activity of 46 GU/ml solution)

To all solutions, 0.5 g of alkyl polyglycoside of the general formula RO(G)x was added, where G is a glucose residue and R is an alkyl chain. The alkyl polyglycoside had various Alkyl chain lengths R and different values for x, the degree of polymerization.

The supports were placed in the solution at 45ºC for 40 minutes. The properties of the alkyl polyglycoside and the results obtained were as follows:

* As used in examples 1 to 3

Example 5

Again, the procedure was as in Example 1. The detergent active used was ethyl 6-O-decanoyl glycoside, which has the formula All solutions contained per liter of water:

Sodium citrate dihydrate 0.60 g

Acrylic acid-maleic acid copolymer 0.15 g

Sodium disilicate monohydrate 0.60 g

Some solutions also included:

30 mg Alcalase 2.0 T (giving an activity of 46 GU/ml) and/or 0.5 g ethyl 6-O-decanoylglucoside.

The solutions were used to wash glass slides soiled with egg yolk as in Example 1 or stainless steel slides soiled with egg yolk in the same manner. The slides were placed in the solution at 45ºC, removed after various periods of time, dried and weighed to determine soil removal as in Example 1.

The results were as follows:

It is evident that the use of enzyme and glucoside together results in a synergistic improvement in soil removal.

Example 6

A dishwasher preparation was a mixture that contained:

The alkyl polyglycoside had the formula RO(G)x, where G is glucose, R is a C₁₂-C₁₄ alkyl chain and x is an average value of 1.8. This preparation was used to wash various soiled glass slides using a Bosch S 510 dishwasher with standard program and without adding salt to the machine. The main wash temperature was 55ºC, the final rinse temperature was 65ºC. The water used was tap water with a French hardness of 16º.

The glass slides were stained with potato, custard or egg yolk. The potato and custard stains were aged at 30ºC and 60% relative humidity for 16 to 24 hours. The egg yolk stain was baked at 120ºC for 2 hours. Stain removal was determined as weight loss. The degree of stain removal was:

Potato 99.7

Vanilla pudding 92.1

Egg yolk 54.0

Example 7

This example shows the synergistic effect in removing stains from glass slides.

New glass slides, 5 cm x 5 cm, were machine washed, repeatedly rinsed with demineralized water and soiled with approximately 55 mg of baked-on egg yolk per slide.

All washing solutions contained in 1 l of water with a French hardness of 16º:

Sodium citrate dihydrate 0.6 g

Acrylic acid-maleic acid copolymer (Sokolan CP5) 0.15 g

Sodium disilicate monohydrate 0.6 g

These materials were added to the water and stirred at 45ºC for 15 minutes. To the solutions was then added:

20 mg Alcalase 2.0 T (providing 30 GU/ml in solution) and/or 0.25 g sodium dodecyl sulfate (SDS).

The solutions were kept at 45ºC.

After 1 minute, slides were placed in the solution. The slides were removed after various periods of time, dried and weighed to determine soil removal. The amount removed was expressed as a percentage of the original soil. In this example only, when a slide was removed from the wash solution, it was replaced with an equally soiled slide that had received the identical treatment in a second, identical wash solution. The results were as follows:

These results demonstrate a synergistic improvement in soil removal by using SDS together with the proteolytic enzyme at rinse times of 20 minutes or more.

Example 8

Example 7 was repeated using a larger amount of enzyme and a larger amount of another anionic surfactant. When the carriers were removed from the rinse solution, they were replaced with a clean carrier. Sequentially added to the wash solutions were:

30 mg Alcalase 2.0 T (which yielded 45 GU/ml in solution) and/or 0.5 g Texin+ ES68, which is a fatty acid ester sulfonate of the formula

is where R² is derived from tallow and thus is predominantly a C₁₀ or C₁₈ alkyl radical and R³ is a methyl radical. (+ trademark)

The results were:

The synergistic improvement when using FAES and enzyme is obvious.

When this experiment was repeated using stainless steel supports, the results were virtually identical.

Example 9

The procedure of Example 7 was repeated using SDS and mixtures of SDS with an equal weight proportion of other surfactants. For each test, the same total amount of surfactant (250 mg/L) was used and 20 mg/L Alcalase 2.OT was present.

The results, expressed as wt% yolk removal after 30 minutes, were:

(+ trademark)

Dobanol 91-6 is an ethoxylated fatty alcohol, where the fatty alcohol has a chain length of 9 to 11 carbon atoms and the average degree of ethoxylation is 6. It has an HLB value of 12.5.

Synperonic A7 is an ethoxylated fatty alcohol in which the fatty alcohol has a chain length of 13 to 15 carbon atoms and the average number of ethylene oxide residues is 7. It has an HLB value of 12.2.

APG 300 is an alkyl polyglycoside of the formula

R⁵O (G)x,

wherein R⁵ is an alkyl radical having 9 to 11 carbon atoms and x has an average value of 1.4.

Example 10

Example 7 was repeated using one of the three nonionic surfactants instead of SDS. The results, expressed as wt% yolk removal after 30 minutes, were:

Synperonic A3 is a C13-C15 fatty alcohol ethoxylated with an average of 3 ethylene oxide residues. It has an HLB value of 7.9. Synperonic A7 is, as mentioned in the last example, a C13-C15 alcohol with an average of 7 ethylene oxide residues. The HLB value is 12.2.

Dobanol 91-6 is a C9-C11 alcohol with an average of 6 ethylene oxide residues. The HLB value is 12.5.

It can be seen that this nonionic surfactant, used alone, was superior to Synperonic A7, used alone.

Example 11

Example 7 was repeated twice using a larger amount of enzyme (as in Example 8) and two ethoxylated nonionic surfactants. Sequentially the following was added to the washing solutions:

30 mg Alcalase 2.0 T (providing 45 GU/ml in solution) and/or 0.4 g either Synperonic A7 or Dobanol 91-6.

The results, expressed as wt% yolk removal, after 30 minutes were:

This confirms the greater synergy with Dobanol 91-6.

Example 12

Example 7 was repeated using a larger amount of enzyme (as in Examples 8 and 11) and two anionic surfactants. The following were added successively to the washing solutions: 30 mg Alcalase 2.0 T (providing 45 GU/ml in solution) and/or 250 mg either Empicol+ LX or 250 mg/l either sodium lauryl ether sulfate (LES) with an average of 3 ethylene oxide residues or the middle fraction of coconut alkyl sulfate (Empicol LX). (+ Trademark).

The results, expressed as wt% yolk removal, after 30 minutes were:

Example 13

Several dishwasher preparations were made. Each contained a mixture:

(+ trademark)

Termamyl is an amylase.

The preparations contained sodium dodecyl sulfate in amounts of 0.75 g, 1.5 g and 3.0 g.

Each preparation was used to wash different soiled glass slides using a Bosch S 510 dishwasher with standard program and without adding salt to the machine. The main wash temperature was 55ºC, the final rinse temperature was 65ºC. The water used was tap water with a French hardness of 16º.

The materials from which the various supports were made, the stains thereon and the extent of removal are given in the table below. In most cases the extent of removal was determined by weight loss. In a few cases the extent of removal was determined by visual inspection of the area remaining covered by stains.

In addition, the pressure delivered by the machine's pump was monitored. This is a measure of the effectiveness of the defoamer, as foaming leads to a loss of pump pressure.

The results are shown in the table below. All washing solutions formed in the machine had a pH of 9.5.

* indicates visual assessment

Example 14

A composition containing Dehypon+ KE 2429 as a foam inhibitor (this is believed to be a mixture of a branched chain alcohol and a ketone according to EP-A 324 339) was used to rinse a 20 cm x 6 cm stainless steel plate with approximately 0.8 g of baked egg yolk in a Bosch 5510 machine. The rinsing conditions were the same as for Example 12. The composition contained:

(+ trademark)

Sodium citrate dihydrate 5.0 g

Sodium dodecyl sulfate 1.25 g

Alcalase 2.0T 0.20 g

Dehypon KE 2429 0.50 g

The removal of dirt, determined as weight loss, was 83%. The average pumping pressure was 73% of the pressure achieved with only water and no load in the machine.

Example 15

Example 14 was repeated, whereby the composition also contained 0.50 g of oleic acid.

The removal of dirt, determined as weight loss, was 91%. The average pumping pressure was 100% of the pressure achieved with water only and no machine load.

Example 16

Various dishwasher preparations were prepared. Each contained a mixture: Amount in weight

Various proteases were included in these preparations, which were then used to rinse porcelain and stainless steel slides soiled with baked-on egg yolk. The results, determined by weight loss, are given in the table below.

All combinations of active ingredient/protease are compatible with the amylases.

Claims (14)

1. A chlorine bleach-free aqueous liquid dishwasher cleaning composition comprising: (a) 0.0002 to 0.05 Anson units per gram of the composition of a proteolytic enzyme; b) 5 to 90% by weight of a detergent builder; c) 1 to 40 wt.% sodium or potassium silicate with a ratio of SiO₂:Na₂O or SiO₂:K₂O of 2.0 to 3.2; d) 3 to 50% by weight of an organic surfactant selected from the group: (1) Glycoside surfactants; (ii) anionic surfactants having a hydrophilic head group which is or contains a sulfate or sulfonate group and a hydrophobic moiety which is or contains an alkyl or alkenyl group having 8 to 22 carbon atoms; (iii) ethoxylated fatty alcohols of the formula RO(CH₂CH₂O)nM, wherein R is an alkyl group having 6 to 16 carbon atoms and n has an average value of at least 4, which is sufficiently high that the HLB value of the ethoxylated fatty alcohol is 10.5 or greater, with the proviso that when the ethoxylated fatty alcohol (iii) is used without anionic surfactant (ii), the majority of the alkyl groups R contain 6 to 12 carbon atoms and (iv) mixtures thereof; e) water, wherein the composition has a pH of 7 to 11 when added to deionised water at a concentration of 2 g/l. 2. Composition according to claim 1, wherein the glycoside surfactant has the general formula wherein G is a residue of a pentose or hexose, R'O is an alkoxy group, x is at least one unit and R is an organic hydrophobic group having 6 to 20 carbon atoms. 3. Composition according to claim 2, wherein R is an alkyl or alkenyl radical having 7 to 16 carbon atoms and x has a value in the range of 1 to 1.8. 4. Composition according to claim 1, wherein the anionic surfactant is selected from: primary alkyl sulfate of the formula: wherein R¹ is a primary alkyl group having 8 to 18 carbon atoms and M is a solubilizing cation, fatty acid ester sulfonate of the formula: wherein R² is an alkyl group having 6 to 16 carbon atoms, R³ is an alkyl group having 1 to 4 carbon atoms and M is a solubilizing cation, alkylbenzenesulfonate of the formula: wherein R⁴ is an alkyl group having 10 to 16 carbon atoms and M is a solubilizing cation, alkyl ether sulfate of the formula: R¹O CH₂CH₂O)nSO₃M wherein R¹ is a primary alkyl group having 8 to 18 carbon atoms, n has an average value in the range of 1 to 6 and M is a solubilizing cation. 5. Composition according to one of the preceding claims 1 to 4, which contains 5 to 25 wt.% sodium or potassium silicate. 6. Composition according to one of claims 1 to 5, which contains sodium silicate with a ratio of SiO:Na₂O of at least 2.4. 7. A composition according to any one of the preceding claims 1 to 6, wherein the total amount of surfactant is 5 to 25% by weight . 8. A composition according to any one of the preceding claims 1 to 7, further comprising a peroxygen bleaching agent. 9. A composition according to any one of the preceding claims 1 to 8, which further contains a defoamer other than a nonionic surfactant. 10. Composition according to one of the preceding claims 1 to 9, which further contains amylase and/or lipase. 11. Composition according to one of the preceding claims 1 to 10 with a pH of 9.0 to 9.5. 12. A composition according to any one of the preceding claims 1 to 11, wherein the detergent builder is a non-phosphate builder. 13. A method of washing dishes and/or glassware comprising exposing the dishes and/or glassware to a mixture of water and a cleaning composition according to any one of the preceding claims. 14. Use of from 3 to 50% by weight of the composition of an organic surfactant as defined in claim 1 as a protein soil removal enhancer in a dishwasher composition containing a proteolytic enzyme and a detergent builder.