The present invention relates to the formulation of a stable, clear, concentrated all purpose liquid cleaning composition and containing more than 10% active ingredients, having improved shining properties, and degreasing properties. The composition comprises a mixture of anionic and nonionic detergents, a foam control agent, a minimal level of a water miscible organic solvent compatible with the fragrance ingredient, and an aqueous vehicle, and is capable of being diluted four times with tap water without a loss in stability while providing a satisfactory cleaning performance.
All purpose liquid cleaning compositions for hard surfaces such as metal, glass, ceramic, plastic, and linoleum surfaces have met with commercial acceptance because they have the advantage that they can be applied to hard surfaces in neat (as is) or concentrated form so that a relatively high level of surfactant material is delivered directly to the soils. However, instability problems can occur when the concentrated products are diluted with tap water by the user. Another problem associated with the previously available concentrated formulations (more than 10% active ingredients) is that a high level of solubilizers (solvents) is generally required in order to obtain a clear and stable composition over a wide range of temperatures.
This invention provides an all purpose liquid cleaning composition in concentrated form which retains its stability upon dilution with water, and provides superior cleaning performance of the ready to use product both in neat and dilute usages. The good cleaning performance is obtained without the need of builders. Consequently, the shining properties are significantly improved over built all purpose cleaning compositions. The concentrated products of present invention offer a further advantage in terms of cost savings for packaging, storage and transportation.
The prior art is replete with liquid all purpose hard surface cleaning compositions which are generally classified in two types. The first type is a particulate aqueous suspension having water-insoluble abrasive particles suspended therein, which particles are palpable. Some of the cleaners of this type suffer a stability problem and consumers may object to their "gritty" feel, the potential for scratching surfaces and the need for extensive rinsing to remove abrasive deposits. The second type is the liquid detergent without suspended abrasive and, seemingly, this latter type is preferred by consumers. While this second type generally is a mixture of surfactant and builder salt in an aqueous medium, the product formulations in the market place have varied widely in composition.
The presence of builder salts as an essential ingredient in all purpose hard surface cleaning compositions to improve the cleaning action of the organic surface active agents, commonly used in an aqueous cleaning composition, i.e. anionic and nonionic surfactants, and to maintain an alkaline pH range, is disclosed in U.S. Patents 4,576,738 and 4,597,887, and in European Patent applications 0165885 and 0080749 and in UK Patent Application 2166153A.
The prior art also discloses cleaning compositions containing a high boiling temperature, water-miscible organic solvent such as propylene glycol or ethylene glycol - monobutyl ether as disclosed in GB patent 2,166,153A. The prior art discloses a binary solvent system of Pinane and an ethylene glycol - or propylene glycol - monoethyl or monobutyl ether as disclosed in U.S. Patents 4,576,738 and 4,597,887; a dual solvent system of dipropylene glycol methyl ether and mineral spirits as disclosed in U.S. patent 4,673,524; and a propylene glycol monomethyl ether and/or dipropylene glycol monomethyl ether as a penetrant to penetrate road film as disclosed in U.S. Patent 4,670,171.
Also disclosed in the prior art is the preparation of a concentrated all-purpose cleaning composition which is diluted with tap water approximately four times prior to usage or storage by the consumer, as disclosed in European Patent 0165885.
US-A-4285841 discloses a laundry composition which has a ternary composition consisting of anionic sulphonates and sulphates, ethoxylated nonionic surface active agents and 8 to 20% of fatty acid having 10 to 22 carbon atoms, and teaches that at least 8% of the fatty acid must be used.
EP-A-0243685 discloses laundry or dishwashing compositions containing 30 to 60% anionic and 5 to 40% nonionic surfactants and does not teach the use of fatty acids.
EP-A-0109022 discloses laundry or dishwashing compositions containing mixtures of anionic and nonionic surfactants in amounts greater than 60%. There is no teaching of the use of small amounts of fatty acids.
FR-A-2189505 disclose a laundry composition containing 25 to 75% of nonionic surfactant and 5 to 25% of anionic surfactant. There is no disclosure of the use of a small amount of fatty acid.
However, none of the above-mentioned patents disclose a stable, clear, homogeneous concentrated all purpose unbuilt liquid cleaning composition containing more than 10% active ingredients and comprising a mixture of anionic and nonionic detergents, a foam control agent, and a water miscible organic solvent selected from the group consisting of C₁-C₄ alkyl ethers of ethylene glycol or diethylene glycol or mono-, di- or tripropylene glycol compatible with the fragrance ingredient, in an aqueous vehicle, capable of being diluted about four times with tap water without any loss in stability, clarity and homogeneity.
It has now been found that a stable, clear, homogeneous concentrated liquid all purpose cleaning composition having improved cleaning and shining properties can be prepared in the absence of a builder salt comprising as the essential ingredients, 14-28% by weight of a dual surfactant system of a mixture of anionic and nonionic surfactants preferably in a weight ratio in the range of 1.25:1 to 1.33:1, a fatty acid foam control agent and 5-15% of a water soluble (miscible) organic solvent selected from the group consisting of an ethylene or propylene glycol ether derivative compatible with the fragrance ingredient, in an aqueous medium. The cleaning performances of the ready to use product, both in neat and diluted usages, are particularly effective in the removal of grease and oily soil and leaves a shining clean surface. These products are effective at varying water hardness levels, have desirable foaming characteristics and leave substantially no spots or streaks either with or without rinsing. Furthermore, the resultant product is clean and homogeneous and stable at temperatures over a wide range, about 5°C-49°C. Optionally, the multivalent magnesium cation, which is normally found in hard tap water, can be added to improve cleaning performances in soft water areas.
Accordingly, the primary object of the invention is to provide a clear concentrated all purpose liquid cleaning composition which is stable over a wide range of temperatures and contains minimal levels of a water soluble organic solvent selected from the group consisting of an ethylene or propylene glycol ether derivative compatible with the fragrance ingredient.
Another object of this invention is to provide a clear, homogeneous and stable concentrated all purpose liquid cleaning composition containing 14-28% by weight of a dual surfactant system of a mixture of anionic and nonionic surfactants.
Another object of this invention is to provide a clear and stable concentrate of an all purpose liquid cleaning composition capable of being diluted four-fold with hard or soft tap water, to produce a clear stable diluted liquid cleaning composition.
Another object of this invention is to provide an all purpose liquid cleaning composition having improved cleaning and shining properties both as a neat and diluted product.
Still another object of this invention is to provide an all purpose liquid cleaning composition free of builder salts, having improved cleaning and shining properties.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realised and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the foregoing and other objects and in accordance with the present invention, so embodied and broadly described herein, the novel stable, clear and homogeneous concentrated liquid all purpose cleaning composition of this invention comprises by weight, 14-18% of a water soluble dual detergent system of a mixture of anionic and nonionic surfactants, and 5-15% of a water soluble polar organic solvent selected from the group consisting of an ethylene-, diethylene-, propylene-, or polypropylene glycol ether derivative, in an aqueous medium free of builder salts, and having a pH of about 6-7.
More specifically, the present invention relates to a stable clear homogeneous concentrated liquid all purpose hard surface cleaning composition free of builder salts, comprising, by weight, 14-28% of a water soluble dual detergent system consisting essentially of a mixture of anionic and nonionic surfactants, there being 8-16% of the anionic surfactant and 6-12% of the nonionic surfactant and 5-15% of a water soluble, polar organic solvent selected from the group consisting of C₁-C₄ alkyl ethers of ethylene or diethylene glycols or mono-, di-, or tripropylene glycol, 0.5-2% of a fatty acid foam control agent, and 1.9-5.5% of a fragrance compatible with the organic solvent in an aqueous medium, and having a pH of about 6-7.
The present novel concentrated liquid all purpose cleaning product, which is suitable to be sold in a pouch or similar packing, can readily be diluted with tap water by the consumer about four times by volume before use. The products are stable in a wide range of temperatures, both "as is" (neat) or when diluted with soft or hard water, and can be used in neat or diluted form.
A preferred optional ingredient is a C₈-C₁₈ fatty acid as a foam control agent in an amount of 0.5-2% by weight of the composition.
The foam behaviour of the ready to use all purpose cleaning composition can be adapted to consumer requirements by properly selecting the nonionic surfactants, i.e., ethoxylated fatty alcohol, ethoxylated/propoxylated fatty alcohol or mixtures thereof.
The essential detergent active ingredients of the present all purpose liquid cleaning composition (APC) constitutes more than 10% active ingredients, and preferably 14-28% by weight of a dual surfactant system comprising at least one water soluble anionic surfactant and at least one water soluble nonionic surfactant, preferably in a weight ratio of 5:4. The combination of anionic and nonionic surfactants exhibit synergistic cleaning performance.
The anionic surfactants which may be used in the detergent composition of the invention include at least one surfactant selected from the group consisting of water soluble salts, particularly alkali metal salts, e.g., sodium or potassium salts of a C₈-C₁₈ alkyl sulfonate or paraffin sulfonate or a C₈-C₁₆ alkyl benzene sulfonate such as dodecyl benzene sulfonate. The multivalent salts of anionic surfactants have a lower water solubility than the alkali metal salts and solubility decreases with increasing concentration of the bivalent ions. The calcium salt of paraffin sulfonate has very poor solubility compared to the magnesium salt. This poor solubility compromises cleaning performance. The preferred anionic surfactant is sodium paraffin sulfonate, preferably phosphate free. The anionic surfactant constitutes about 8-16% of the concentrated all purpose cleaner.
The incorporation of minimal amounts of magnesium ions has been found to boost the cleaning power of the anionic detergent. The grease cutting ability of the various compositions is directly related to the Mg concentration; the higher the Mg concentration the better the degreasing. In the concentrated APC, paraffin sulfonate: Mg cations ratios may be reduced to less than 2:1 to allow for additional magnesium ion brought into the solution from hard water when the user dilutes the cleaner. All of the magnesium containing compositions are sensitive to phosphate contamination. Magnesium ions react with phosphate anion (more particularly pyrophosphate) yielding an insoluble precipitate of Mg phosphate. Most compositions with high paraffin sulfonate levels (16%) show a precipitate due to the phosphate ions present as a by product in ordinary grades of paraffin sulfonate. For this reason, when higher levels of paraffin sulfonate are present, it is preferable to use phosphate free paraffin sulfonate in the concentrated composition containing magnesium salts. Such grades are commercially available from several major suppliers.
Accordingly, magnesium ions in the form of a water soluble magnesium salt, such as magnesium sulfate heptahydrate, which is commercially available, are an optional ingredient present in amount of 1.5-6% preferably 1.5 to 4% by weight. The boosting action of the magnesium ions is particularly useful in soft water areas. A stoichiometric ratio between paraffin sulfonate ions and magnesium ions in the compositions give satisfactory results in terms of cleaning performance and water solubility, however, it is not necessary to add magnesium ions because the performance objectives of the all purpose cleaning compositions can be obtained without the magnesium ion booster.
The nonionic detergents used in the cleaners according to the present invention can be broadly described as water-soluble or water-dispersible compounds produced by the condensation of hydrophilic ethylene oxide groups, and/or propylene oxide groups, with an organic hydrophobic aliphatic or alkyl aromatic compound having a terminal hydroxy group. Such detergents are prepared readily by condensing the hydrophobic organic compound with ethylene oxide, and/or propylene oxide or with a polyglycoside. Further, the length of the polyethylenoxy chain can be adjusted to achieve the desired balance between the hydrophobic and hydrophilic elements.
The satisfactory nonionic detergents include the condensation products of a higher alkanol containing about 8 to 18 carbon atoms in a straight or branched-chain configuration condensed with about 2.5 to 30 moles of ethylene oxide. Preferred examples of these detergents are the condensates of C₈-C₁₁ alkanol with 2.5 moles of ethylene oxide or 5 moles ethylene oxide, and condensates of C₁₃-C₁₅ alkanol with 7 moles of ethylene oxide and 4 moles of propylene oxide. The nonionic surfactant, preferably selected from the group consisting of ethoxylated fatty alcohol, ethoxylated/propoxylated fatty alcohol and an alkyl polyglycoside, constitutes 6-12% by weight of the composition.
The use of a mixture of sodium paraffin sulfonate and nonionic surfactants provides very good cleaning performance for removal of greasy soils, both when the product is used neat as well as when it is diulted with water.
The nonionic surfactant ingredient not only optimises the cleaning performance of the anionic surfactant, but also assists in adapting the foam behaviour of the ready to use all purpose cleaning formulation to consumer requirements. Foam behaviour is adjusted by using a mixture of medium and low foaming nonionics. One such suitable foam control mixture is an ethoxylated fatty alcohol such as C₈-C₁₁ alcohol ethoxy oxide 5:1, and an ethoxylated/propyoxylated fatty alcohol such as C₁₃-C₁₅ alcohol ethoxy oxide 7:1 propoxy oxide 4:1 in a 2:1 weight ratio.
The primary foam control agent is a fatty acid containing 12-18 carbon atoms or a mixture of such fatty acids, such as coconut oil fatty acids, in an amount of 0.5-2% by weight of the composition. The use of 0.5% fatty acid provides a foam control similar to regular AJAX APC, a commercial product on the martket, in hard and medium water hardness areas (respectively 300 and 150 ppm as CaCO₃). However, 1% fatty acid provides better foam control in hard water as well as in soft water.
The water soluble polar, organic solvents used in the present all purpose cleaning compositions are nonvolatile (high boiling point), and may be described generally as a C₁-C₄ alkyl ether of a compound selected from the group consisting of monoethylene glycol, diethylene glycol, and mono-, or di- or tri- propylene glycol. The methyl ether of mono-, di-, or tri-propylene glycol conforms to the formula:
wherein n has a value of 1-3. The mono- propylene glycol methyl ether has an n value of 1. The dipropylene glycol methyl ether has an n value of 2. The tripropylene glycol methyl ether has an n value of 3. Specific examples of the water soluble organic solvents include the following propylene glycol ether derivatives: mono-, di-, and tripropylene glycol methyl ether, mono-, di-, and tripropylene glycol butyl ether. The ethylene glycol ether derivatives include mono- and diethylene glycol butyl ether. The solvent is optimized to obtain a stable product using a minimal level, preferably 5-15% by weight of the composition. The solvent is also selected based on its odour which is easily covered by APC fragrance and to be compatible with the selected fragrance ingredient. Diethylene glycol monomethyl and monobutyl ether, and tripropylene and dipropylene glycol monomethyl ether have odours easily covered with the perfume ingredient.
The level of fragrance is also optimized to achieve a cleaner with high cosmetic impact both as is, in the ready to use form, and when diluted preferably in an amount about 2-5% by weight of the composition. The perfume or fragrance, which is a nonwater miscible material, is readily solubilised by the water soluble organic solvent in the aqueous vehicle, yielding a clear single phase. Suitable types of fragrances are floral, pine and lemon.
The final essential component of the present novel composition is water, ether hard or soft water or deionized water. This component represents the balance of said compositions reduced by any optional ingredients which may be present.
The all purpose cleaning compositions of this invention also may contain minor amounts of conventional additional components in order to impart any desired characteristic, which are compatible with the essential ingredients and do not adversely effect the stability and cleaning performance of the liquid composition. Suitable additives include colouring agents, or dyes, preservatives such as formaldehyde (Formalin) and Kathon 886 molecular weight, hydrotropes such as sodium cumene sulfonate and antiseptic agents. These additives constitute a maximum of 5% and preferably a maximum of 3.2% by weight of the composition.
In one form of the invention the anionic surfactant is 10% sodium paraffin sulfonate, and the composition further comprises 1.5 to 3.75% of magnesium sulfate heptahydrate.
In another form of the invention the anionic surfactant is 10% sodium paraffin sulphonate, and the composition further comprises 2.5 to 3.75% of magnesium sulfate heptahydrate and 2.0 to 3.2% sodium cumene sulfonate hydrotrope salt.
In the concentrated or diluted form, the all purpose liquid cleaners are clear and homogeneous and exhibit stability at reduced and increased temperatures. More specifically, the compositions are stable at 4°C, room temperature, 35°C and 43°C. Such compositions exhibit a pH in the range of about 6.0 to 7.0, preferably 6.1-6.8. Product stability is also a function of the pH of the finished product. The liquids are readily pourable and free flowing from any suitable container such as metal, plastic, or glass bottles, bags, cans or drums.
Typically, the inventive compositions are manufactured in an agitated mixing vessel optionally equipped with a heating and/or cooling jacket. Generally, the temperature of the mixture will be maintained in the range of 15°C to 38°C, during manufacture. While the order in which the individual ingredients are added can be varied, best results are obtained by adding the anionic surfactant to the water with mild agitation. After complete dissolution of the anionic surfactant the nonionic surfactant(s) is added. Next, the organic nonaqueous solvent is added with moderate agitation to form a homogeneous mixture. Thereafter, the perfume is added with moderate agitation until dissolved. Usually, the optional ingredients such as colour, preservative, and magnesium sulfate salt are the final ingredients added with agitation to form a homogeneous all-purpose clear liquid cleaning composition. The final product both in concentrated and diluted form has long term stability and exhibits improved shine, improved foam control and cleaning performance, mildness to hands and safety to cleaned surfaces, as well as cosmetic attributes including clarity, low viscosity and pleasant fragrance.
The following examples illustrate liquid cleaning compositions of the described invention. Unless otherwise specified, all percentages are by weight. The exemplified compositions are illustrative only and do not limit the scope of the invention.
Optional ingredient : preservative
The compositions of Examples 1 and 2 are clear homogeneous liquids, stable at temperatures of 4°C to 43°C, and have improved cleaning and shine performance in soft and hard water.
Example 7, free of Mg salts and containing phosphates, an impurity present in some grades of commercial Na paraffin sulfonate, is a clear homogeneous stable liquid composition at room and high temperatures; whereas Exs. 3-6 and 8, containing the magnesium salts in varying amounts (1.5-3%), are not stable due to the reaction of the MgSO₄ salt with the phosphate to form the Mg phosphate precipitate.
Ex. 9, containing phosphate-free Na paraffin sulfonate, can contain the MgSO₄ salt in amounts as high as 3% and yield a clear, homogeneous stable liquid because there is no phosphate present in the composition.
Example 11 is a comparison example. It does not contain DEGMBE and as can be seen is unstable at low temperatures forming two phases.
The compositions of Examples 10 and 12 containing a considerably lesser amount of Na paraffin sulfonate (10%) than the 16% in Example 3 provide a low amount of the phosphate impurity, insufficient to react with the MgSO₄ ingredient to form a Mg phosphate precipitate. Clear homogeneous stable liquid cleaners at low and high temperatures are formed having improved cleaning and shine properties.
Example 11 containing no organic solvent is an unstable composition.
In Example 13, the addition of the hydrotope, Na cumene sulfonate, in the presence of MgSO4 and decreased DEGMBE solvent content, produces a clear, homogeneous stable liquid cleaner having improved cleaning performance.
Examples 14 and 16, free of the optional ingredients MgSO₄ salt and the hydrotrope salt, produce clear, homogeneous stable liquid APC cleaner having improved cleaning and foam control properties.
Example 15, containing the optional ingredient, SCS hydrotrope salt, also produces a clear, homogeneous stable liquid cleaner having improved cleaning and shine properties.
The compositions of Examples 17 - 23 are all clear, homogeneous stable liquids having improved cleaning and shine properties. However, Examples 21 and 22, containing ethanol and isopropyl alcohol, have lower boiling and flash points which may preclude manufacture or use of these compositions at higher temperatures. These are provided as comparison examples.
The composition of Examples 24-33, containing a variety of perfumes in amounts of 2.4 to 5.2% by weight, are clear, homogeneous stable liquid cleaners having improved cleaning and shine performance.
The compositions of Examples 34 - 36 are clear homogeneous stable concentrated liquids having improved cleaning and shine performance and foam control, dilutable 4:1 with soft, medium, or hard water.