NO136935B - UNBUILD LIQUID FLUID MIXTURE. - Google Patents

Description

The invention relates to washing-up agents which facilitate the removal of food residues from aluminum or aluminum alloy surfaces.

Attachment of burnt/cooked food residues, e.g. sauce, milk puddings, eggs, meat, to aluminum or aluminum alloy cookware is a serious problem in the home or institutional household. The fat and protein part of the dirt is known to be the most difficult to remove during the washing-up, especially if there has been burn-in on the surface.

Up until now, the only practical method for removing this stubborn dirt during the dishwashing has involved mechanical scrubbing using scouring powders, pastes or scouring pads. Such scrubbing is unpleasant and sometimes damages both the vessel and the hands of the person washing the dishes. An extended soaking period in water or in an aqueous solution of active detergent before washing the dishes is a time-consuming alternative.

The invention provides a detergent mixer for manual dishwashing which, during the washing step of the dishwashing process, deposits a temporary protective film on an aluminum or aluminum alloy surface. This protective film is not removed during the usual manual drying of the dishes washed with the mixture in the dishwashing operation. This film substantially prevents dirt resulting from subsequent use of the vessel from forming a solid adherent mass directly on the metallic surface of the vessel.

A subsequent washing-up process is significantly facilitated by the fact that cooked/burnt food residues including such dirt which is known to be most resistant to removal, namely heat-decomposed protein-containing dirt, e.g. soup, scrambled eggs, porridge, milk, and also sausages, eggs during frying, are easier to remove. The mechanical scouring can be reduced to a minimum. The film is termed "anti-fouling".

The agent which provides the film is termed an "anti-fouling agent" and is defined below.

It is well known that the housewife prefers a washing-up liquid mixture that gives a good volume of stable foam when used in water in significant dilutions by hand heating, and that this foam should be stable against foam-inhibiting food residues. the products according to the invention provide foams that fulfill the above-mentioned desires.

The invention therefore seeks to provide detergents for manual dishwashing which, when used in a diluted aqueous solution, provide both an anti-fouling effect and stable foam regardless of the hardness of the water.

It will be understood that commercially viable liquid detergent compositions are those which have a consumer-acceptable concentration of active detergent in the package, i.e. as sold, and which are also effective at the dilution in which the consumer is expected to use them. Accordingly, it is wise to include in the package at least 10% active detergent material, calculated by weight of the entire composition, and to ensure that when it is diluted for use in water to approx. 0.1-0.2% by weight of the entire composition, properties are achieved with regard to anti-fouling and foaming.

Consequently, the invention provides an unbuilt liquid detergent mixture with a pH value of 3.5-6.5 for manual dishwashing with a defined foam ratio containing an anionic synthetic detergent and an anti-soiling agent as defined here.

The foam ratio is defined as equivalent to at least 70% of the foam ratio of a control liquid consisting of sodium dodecyl benzene sulfonate, coconut alcohol ether sulfate (3 ethylene oxide), and coconut ethanolamide in the respective weight ratios of 1:1:0.1 in a modified Schlacter-Dierke's test which is described below ("At least 70%" is chosen as a foam ratio of less than 70% in this control sample is considered unsatisfactory by the average consumer).

The Schlacther-Dierkes test is based on the principle described in Fette und Seifen 1951, vol. 53, p. 207. A 100 ml aqueous solution of the washing-up liquid with 0.06% total detergent active material in water of 24°H temporary hardness at 45°c is stirred rapidly using a vertically oscillating, perforated disk inside a graduated cylinder. The initial foam volume is noted. 0.8 grams of dirt (9.5 parts commercial shortening, 1/4 part oleic acid, 1/4 part stearic acid dispersed in 120 parts water, and the emulsion stabilized with 10 parts wheat starch) is added, and the solution is carefully stirred with the perforated disk for 30 seconds for dispersion. This is followed by 30 seconds of rest after which the foam volume is recorded. A further aliquot of the same dirt is added, and the procedure is repeated until 5 additions of dirt have been made. The test is stopped at this point, and the sum of the measured foam volumes is calculated. The use of this technique, which measures the sum of only the first 6 foam volumes (5 after dirt addition plus the original foam volume) corresponds to the exhaustive test where dirt is added until there is no more foam left, and has the advantage of avoiding the need for a " endpoint" provision.

The control liquid provides a cumulative foam volume of 800 ml of foam. The cumulative foam volumes of the products according to the invention are expressed as a percentage of this and are consequently at least 560 ml of foam.

The above foam ratio test is believed to be an improved test over that previously described. It will be understood that it measures the ability of the foam to resist the effect of the defoamers in the dirt.

The anti-fouling film is provided by an anti-fouling agent which is defined as an agent which satisfies the following test: The inner surface of a small 12.7 cm diameter aluminum box roll is prepared by scouring in hot tap water with a non-woven nylon cloth impregnated with mineral abrasive until the surface is completely wetted by the water. The saucepan is then dried with a paper towel. 25 ml of an egg/milk mixture in the ratio 50:50 in volume is emptied into the saucepan in the usual way. The mixture is boiled for 1 1/2 minutes on an electric hot plate held at 200°C, without stirring. Under these conditions, the egg/milk mixture produces a coherent light brown residue that sticks to the pan when the loose bulk of the cooked mixture is scraped out with a wooden spoon. This soiled pan is immersed in a solution of 0.01% material determined to be an antifouling agent in distilled water at pH 5, and manually scrubbed with the above-mentioned abrasive cloth for 60 seconds, during which time all the burnt dirt. Rinse the saucepan in tap water and dry with a paper towel ■.

The boiling procedure with the egg/milk mixture is repeated, after which the soiled pan, which has been freed of the loose bulk of dirt, is immersed in the same (used) solution as above, for 30 seconds. A soft polyurethane sponge is then used manually to remove the adhering residue. If the pan is completely clean after 15 seconds of rubbing, the test ends and the result of 1 wash/boil cycle is recorded. If the dirt cannot be completely removed with the sponge within 15 seconds, a further 15 seconds of scrubbing with the above-mentioned abrasive cloth is carried out. The saucepan is then rinsed and dried as before and subjected to the above-mentioned egg/milk boiling process. The soiled saucepan, which has been freed of the loose main mass of dirt, is immersed in the same (used) solution for 30 seconds. If the dirt can be removed within 15 seconds with the soft sponge, the result is recorded 2 wash/boil cycles. If not, the test is repeated until purity is achieved after 15 seconds.

An anti-soiling agent is one where complete removal of soil residues can be achieved with a soft sponge within 15 seconds in 3 or fewer wash/boil cycles.

The above definition of anti-fouling agents is considered to be a more practical and satisfactory way of determining the anti-fouling agent than the method previously stated.

The detergents for manual dishwashing according to the invention are based on anionic synthetic detergents for their foaming ability. Non-ionic detergent can be mixed in, but is unsuitable as the only detergent when it comes to obtaining the necessary foam. The term "anionic synthetic detergent" excludes the surface-active organic phosphorus compounds to which reference will be made later.

Suitable anionic synthetic detergents are α- and randomised C-10-olefin sulphonates, c11-15-alcohol ether (3 ethylene oxide) sulphates, alkyl-<C>10-14-benzenesulphonates, alkane-c13-12-sulphonates and c12-12 primary or secondary alcohol sulphates.

It is well known that phosphates react with aluminium. It has been suggested that the organic phosphates, C4-20-alkyl phosphates be used in a scouring pad, the phosphate ester being believed to form a residual hydrophobic film on the surface of a scoured pan. It is also known that alkyl phosphates in formulated laundry products are foam suppressants for the foam developed by the anionic surfactant detergent component in these products.

It has now been found that surface-active organic phosphorus compounds, if very carefully selected, can provide the anti-fouling film under manual dishwashing conditions, surprisingly without damaging the defined lather ratio. It has now also been found essential that the limited solubility in water of these in carefully selected surface-active organic phosphorus compounds increase s.

Accordingly, the invention provides an unstructured liquid detergent mixture as indicated above, characterized in that it contains the combination of the per se known compounds: 1) 10-50% sulfonate or sulfate surfactant detergent,

2) 1-15% organic, possibly ethoxylated, phosphate ester,

3) 2-18% solubilizing agent and

4) 3-40% pH-regulating agent,

in aqueous solution, where the antifouling agent is a per se known surface-active organic phosphorus compound of the general formula:

where n is 0-5; R-^ and R2 are hydrocarbon chains where R-^ is -(CH2)XCH3 or -(CH2)X<C>6<H>5, R2 is -(CH2)yCH3 or -(CH2)yC6<H>5, and R3 is:

>CH - (CH2)2 -,

>CH - (CH2)Z - C6H4 -,

>C6H3 - (CH2)2

or - CH. (CH2)z -

- CHOH

where x, y or z can be 0; x+y+z amounts to 7-17 when alkylhydrocarbon-organic groups are used in R-1, R2 and R3; x+y+z amounts to 6-16 when aryl or hydroxyalkyl organic groups are used in R3, solubilized with a solubilizing agent selected from:

a) primary and secondary aliphatic alcohols and vicinal diols with a chain length of 10-16 carbon atoms with an average of 7-20 mol of ethylene oxide per moles of alcohol/diol; b) alkali metal, ammonium or substituted ammonium salts of Cn-<C>15-ether (2-10 ethylene oxide) sulfates,

and added an organic acid for setting the pH value, the organic acid having at least one pKa value in the range 2.5-6.5.

When the products according to the invention are used in hard water, even more careful selection of the organophosphorus compound referred to above is necessary because of: (a) their sensitivity in solution to precipitation of calcium and magnesium ions present in naturally occurring hard

water,

(b) their insoluble calcium and magnesium salts which are active

defoamers,

(c) the anionic synthetic detergent present in the products of the invention which can be adsorbed on aluminum and, although it does not provide an anti-fouling film, nevertheless reduces the area of the aluminum surface available to the organic phosphorus compound .

The effect of the hardness of the water on the properties of the products according to the invention is reduced by the mixing of the pH-regulating agent- All varieties of household water can be used for washing dishes when only the organic phosphorus compound, the solubilizing agent, the surface-active detergent and the pH-regulating agent are selected carefully.

In the preferred surface-active organic phosphorus compound, x+y+z is equal to 9-13 in the case of alkyl groups, and 6 or 14-16 in the case of aryl or hydroxyalkyl groups. At least two terminal groups R1_ and R2 are essential for the properties with regard to anti-fouling and foam conditions in dishwashing operations carried out in all naturally occurring water. The compounds are preferably used in their monosalt form, i.e. sodium, potassium, ammonium or substituted ammonium. Although compounds with more than two terminal groups can be successfully used, they are not recommended

due to the fact that they cause biodegradation problems.

Examples of preferred organic phosphorus compounds are the phosphate monoesters of:

(a) an adduct of p-tertiary nonylphenol and an average of

2 or 4 ethylene oxide molecules per moles of phenol,

(b) an adduct of ditertiary nonylphenol and an average of

8 ethylene oxide molecules per moles of phenol,

(c) C1-C15 arbitrary secondary alcohols,

(d) an adduct of C-^-Cis arbitrary secondary alcohols and et

average of 3 ethylene oxide units per molecule,

(e) an adduct of C-^-Cis-rarbitrary secondary alcohols and et

average of 1 ethylene oxide unit per molecule,

(f) 7-ethyl, 2-methyl-.4-undecanol,

(g) ^g-arbitrary vicinal diols,

(h) an adduct of c^^_^g-arbitrary vicinal diols and an average of 3 ethylene oxide molecules per mole of diol.

It will be understood that commercially available ethoxylated alcohols may contain relevant ethylene oxide distributions which vary within wide limits. Some polyethylene oxide nonionic intermediates contain significant (up to 25%) amounts of non-ethoxylated alcohol, while others do not.

Thus, the average ethylene oxide content does not always relate to the predominant ethylene oxide groups. Phosphate monoesters derived from ethoxylated alcohols or alkylphenols containing at least 10% of 0-5 relevant ethylene oxide molecules per mole of alcohol/phenol is suitable.

Commercially produced phosphate monoesters invariably contain some diesters, esters of higher phosphoric acids and free phosphoric acid. These contaminants have been found to have little or no effect on the anti-fouling and foaming properties of the compositions of the invention as far as dishwashing is concerned. However, it is desirable to keep any unphosphated non-ionic material to a minimum.

It will be understood that there is some inorganic phosphate which is inevitably contained in the products according to the invention, as they originate from the esters. This is insufficient to effect construction, and the products are therefore "unbuildable".

The solubilizing agent is incorporated for the purpose of keeping the antifouling agent in aqueous solution and to help prevent the precipitation of the antifouling agent by calcium and magnesium ions in hard water. The solubilizing agent is sufficiently soluble to form clear solutions of itself in hard water at 0.05% concentration and thus avoid interference with the antifouling agent on the aluminum surface.

The solubilizing agent is defined as a soluble nonionic or anionic compound of medium to high HLB (W.C. Griffin, J.soc.Cosmetic Chemists, 1, p. 311, 1949).

Preferred solubilizing agents are: octylphenol with an average of 8 or 11.5 ethylene oxide units per molecule;

nonylphenol with an average of 12 ethylene oxide units per molecule; tridecyl alcohol with an average of 14 units of ethylene oxide per molecule; C-j^ -^-synthetic primary alcohol with an average of 12 or 15 units of ethylene oxide per molecule; C11_15-arbitrary

secondary synthetic alcohol with an average of 7.9 or 12 units of ethylene oxide per molecule; C^^^-arbitrary vicinal diols with an average of 12 ethylene oxide units per molecule: phosphate monoesters of C-^-C^-arbitrary. secondary alcohols with an average of 9 ethylene oxide units per molecule; as well as a- and.arbitrary ^g-olef insulf ortates .

It is clearly convenient to use a commercially available material which satisfies both the antifouling test and which falls within the definition of the solubilizing agent. One such material is a mixture of monoalkyl phosphate ester ethylene oxide adducts, where the "up to 5" adduct can be used as an antifouling agent and the "5-15" adduct as the solubilizing material. Preferred solubilizing agents are those which contain little or no unethoxylated alcohol, phenol or diol.

The aforementioned solubilizing agents have the further advantage that they improve the lather of the anionic synthetic detergent without appreciably interfering with the anti-soiling effect.

When using the detergent mixtures according to the invention when a surface-active phosphorus compound is used as an anti-fouling agent, it is essential that the washing-up solution made from these should be acidic, in order to prevent the formation of the dianionic form of the phosphate which is very susceptible to precipitation of calcium and magnesium ions found in naturally occurring water. The pH value when phosphate is used should not be greater than 6. Preferably the pH values when used are 4.5-5.5, and the pH regulating agent, effective in the pH range 3.5-6.5 is essential for the anti-fouling and foaming properties in hard water.

The pH regulator, which is an acid with at least one pKa value

in the range 2.5-6.6, can be selected from acetic acid, malic acid, maleic acid, tartaric acid, propionic acid, citric acid, lactic acid and malonic acid and mixtures of these "in their acidic form or as partial alkali metal/ammonium/amine salts , when clear liquid products are required, and among phthalic acid, adipic acid, ■ fumaric acid and benzoic acid (which is less soluble) when suspensions in liquid products are acceptable.

Sufficient pH-regulating agents must also be included to overcome the natural buffering effect (pH 6-7) in hard water containing carbonate/bicarbonate ions. 3-740% pH regulator by weight of the entire product is therefore included, mostly depending

on the type of water encountered.

The anionic synthetic detergent which is responsible for the foam ratio and cleaning performance of the dishwashing detergent should be selected from those specified above.

Of these anionic synthetic detergents, the olefin sulfonates and ether sulfates can fulfill the functions that apply to both foaming and solubilization.

The hydrolysis properties should be kept in mind because the products are used under acidic conditions.

Mixtures of the appropriate anionic synthetic detergents may be used.

The products according to the invention provide in use 0.02-0.08% anionic synthetic detergent, preferably 0.05%,

and 0.002-0.03% antifouling agent, preferably 0.005-0.01%. Preferred products also include 0.01-0.05% solubilizing agent, and 0.01-0.05% pH adjusting agent, preferably 0.02-0.03%, all by weight of the aqueous product as used. As marketed, i.e. in a more concentrated form, the products comprise 10-50% total active detergent, of which 5-35% is anionic synthetic detergent, 1-15% anti-soiling agent, and 2-18% is solubilizing agent, and 3 - 40% pH regulator.

The ratio of solubilizing agent to antifouling agent incorporated is usually from 1:1 to 5:1 for non-ethoxylated antifouling agents. In the case of ethoxylated antifouling agents, the amount of solubilizing agent is usually up to a 3:1 ratio. The solubilizing agent is present in an amount of up to half the weight of the anionic synthetic detergent.

The selection of the weight ratio between anionic synthetic detergent and anti-soiling agent must be done carefully. For example, a liquid detergent composition containing the phosphate monoester of C-^ .^-seconds alcohol with an average number of 3 ethylene oxide molecules per moles of alcohol, anionic synthetic detergent in the following weight ratios which are critical for achieving the defined foaming and anti-fouling effects: 15:1 to 3-.1 anionic synthetic detergent : ethoxylated phosphate (n = 1-5), while it does not -ethoxylated esters require from 20:1 to 3:1.

Products containing the higher ratios of the anionic synthetic detergent to the antifouling agent are most suitable when the pH values at the lower end of the preferred pH range of the solution are used. Lower ratios of anionic synthetic detergent to antifouling agent are used at the upper end of the preferred pH range in solution.

The products according to the invention are preferably sold so that they contain 30-50% total active detergent material

This material includes anti-fouling agents, e.g. the alkyl phosphate, the anionic synthetic detergent, the solubilizing agent, etc., although they may be composed of up to 10% total detergent active material. The concentration of total active detergent will naturally determine the recommended dilution. In general, it is recommended to dilute a product, as it is sold, with an amount corresponding to a dilution of approx. 500 times. Therefore, the product, as it is sold, is composed so that it gives

a solution for use in water of approx. 0.07% total active detergent, of which 0.003%-0.009% is the anti-soiling agent. For those products that have 30 to 50% total active detergent, the minimum content of anti-soiling agent, for example an alkyl phosphate monoester, should be approx. 3% for the ethoxylated phosphate monoester and 1% for the non-ethoxylated phosphate monoester.

Although the above has indicated the amounts of the essential ingredients to provide the benefits of anti-soiling and foaming properties simultaneously, for certain markets it may be desirable to include up to 5% additional detergents such as cationic, amphoteric or zwitterionic additional detergents.

The products can also include the usual ingredients, e.g. hydrotropes, and viscosity modifiers, in amounts of up to 15% by weight of the total composition when a homogeneous liquid product with a high active detergent content as well as opacifying agents, perfumes and dyes is required.

In the following, the invention will be described using examples where numbers and percentages indicate weight, and where EO means the average number of molecules of ethylene oxide.

EXAMPLES 1 - 10.

Mixtures were made which contained 40% total detergent active material, 10% ethanol, 10% citric acid, and the rest was distilled water. The product was tested using the foam test and anti-fouling test described above at 0.06% total detergent in water of 24°H permanent hardness at pH 4.8. Anionic synthetic detergent: (I) (1) sodium dodecylbenzenesulfonate

(2) sodium C-^-C^g-α-olefin sulfonate (3) sodium C-^-C^g-arbitrary alkanesulfonate Soluble driving agent: (II) C-^-C^-sec. alcohol 12 EO Antifouling agent: (III) C^-C^-sec. alcohol 3 EO phosphate (50% monoester content) The products designated A to M are outside the invention and are included to show critical points in compositions.

The first 3 sets of values given above show that when using ethoxylated (n = 1-5) monoalkyl phosphates in the presence of non-ionic solubilizing agent, the foam conditions are only satisfactory (70% of control sample) when the ratio of anionic surfactant to ethoxylated monoalkyl phosphate is approx. 3.0:1, and that the anti-fouling standard is only achieved when the ratio is less than approx. 15:1.

Examples 7-10 and Comparative Examples J-M demonstrate the advantage of olefin sulfonate over alkylbenzene sulfonate in that sufficient foam and antifouling can be obtained in the absence of a solubilizing agent. Alkanesulfonates behave similarly to alkylbenzenesulfonates and require a solubilizing agent.

EXAMPLES 11-15

describes liquid dishwashing detergent mixtures according to the invention:

The foam ratio and anti-fouling results reported for Examples 1-15 and for Comparative Runs A-M were determined by the test previously described.

EXAMPLE 16

describes a paste according to the invention for incorporation into a scouring pad.

Mixed to a paste for injection in an abrasive carrier, e.g. steel wool, non-woven nylon fleece or a non-woven abrasive-part-filled nylon fleece.

None of the products according to the invention, nor the films that are deposited on the surface, are toxic or prone to decomposition with the emission of harmful fumes or toxic components. The products are suitable for the household or for use on a large scale when washing dishes manually. They are gentle on the skin and have excellent cleansing properties.

The term alkyl phosphates includes the free acid form and the partial salt form. They can be the partial salts with sodium, potassium, ammonium or substituted ammonium.

Claims (3)

1. Unstructured liquid detergent mixture with pH=3.5-6.5 for manual dishwashing with a defined foam ratio and containing an anionic synthetic detergent and an anti-soiling agent, characterized in that it contains the combination of the compounds known per se: 1) 10-50% sulfonate or sulfate surfactant detergent, 2) 1-15% organic, possibly ethoxylated, phosphate ester, 3) 2-18% solubilizing agent and 4) 3-40% pH-regulating agent, in aqueous solution, where the antifouling agent is a per se known surface-active organic phosphorus compound of the general formula: where n is 0-5; 1^ and R2 are hydrocarbon chains where R^ is ~(CH2^XCH3 or -(CH^C^, R2 is -(CH2)yCH3 or -(CH2)yc6H5' 0<? R3 is: y CH - (ch2) z -, >CH - (CH2)z - C6H4>C6H3 - (CH2)z -, or - CH.(CH~) I 2 z - CHOH where x, y or z can be 0; x+y+z amounts to 7-17 when alkylhydrocarbon-organic groups are used in R^ > &2 and ; x+y+z amounts to 6-16 when aryl- or hydroxyalkyl-organic groups are used in R^, solubilized with a solubilizing agent selected from: a) primary and secondary aliphatic alcohols and vicinal diols of -chain length 10-16 carbon atoms with an average of 7-20 mol of ethylene oxide per moles of alcohol/diol; b) alkali metal, ammonium or substituted ammonium ium salts of C-»,C,r-ether (2-10 ethylene oxide) sulfates, 11 lo and added an organic acid to adjust the pH value, the organic acid having at least one pKa value in the range 2.5-6.5. 2. detergent mixture as stated in claim 1, characterized in that the solubilizing agent and the anionic synthetic detergent consist of a c, , , 0-olefin sulfonate. 3. Detergent mixture as stated in claim 2, characterized in that the weight ratio between solubilizing agent and the phosphorus compound is from 1:1 to 3:1 and that the weight ratio between anionic synthetic detergent and the phosphorus compound is from 15:1 to 3:1.