DE3852571T2 - Detergent composition for hard surfaces. - Google Patents

Description

Background of the invention Field of the invention

The invention relates to liquid, aqueous, stable, effective, safe, non-scratching cleaning compositions for hard surfaces, commonly referred to as abrasive cleaners. The compositions are physically stable, do not separate, assuring the user of the optimum effectiveness expected from the various components and their amounts and ratios to one another, they are safe and do not scratch the surfaces commonly cleaned, such as glass, porcelain, ceramics, plastics, metal, wood and lacquered wood (enamelled and varnished).

(2) Discussion of the state of the art

There are, of course, many liquid abrasive compositions in the art that are claimed to work in a safe and effective manner and others that are claimed to be physically and chemically stable, etc.

Some examples of prior art abrasive compositions include US-A-4 005 027 which describes compositions comprising clay and insoluble abrasives. Only inorganic abrasives are described. The compositions include surfactants that do not bleach. Non-ionics are not used. The products are claimed to be physically stable and also do not "significantly run down vertical surfaces" (column 10, lines 45 to 47). such stability is caused by a thixotropic fluid formed by the use of soap and attapulgite clays in such compositions. The compositions of US-A-4,116,849 are very similar to the compositions known from US-A-4,005,027. US-A-4,116,849 additionally discloses the use of thixotropic agents such as colloidal silica, polystyrenes, sulfonated polystyrenes, polyethylenes, oxidized polyethylenes, propylenes, copolymers of styrene and methacrylic acid, methyl or ethyl acrylates, vinyl acetates and others in place of the preferred soap and attapulgite clays; the patentee states that "...ethoxylated nonionic surfactants are to be avoided." Neither of these two patents discloses that soaps or fatty acids are equally suitable materials. US-A-4,240,919 discloses compositions of polyhydric tallow soap, water and water-insoluble abrasives. Various abrasives are disclosed and "melamine, urea-formaldehyde resins, rigid base polymer materials such as polyurethane foam..." (column 3, lines 10 to 12) are listed among the "organic" abrasives. Optionally, "any surfactant materials compatible with the other components in the composition of the invention..." may be present. These include water-soluble anionic, nonionic, amphoteric, cationic and zwitterionic surfactants" (column 3, lines 57 to 62). Further reference is made to US-A-4 051 056 (expanded perlite as abrasive), US-A-4 457 856 (polyacrylate abrasive), DE 19 56 616 (polyvinyl chloride as abrasive), DE 3 645 904 (skin cleanser containing polymeric abrasive material).

GB-A-1 534 680 (corresponding to US-A-4 302 347) discloses liquid aqueous compositions suitable for cleaning hard surfaces and comprising sulphonate or sulphate surfactants, non-ionic detergents (hydrophobic compounds condensed with ethylene oxide), an electrolyte, a fatty acid and an abrasive. However, this document only shows natural abrasive agents such as feldspar, calcite or silica. Polymeric abrasives are not suggested. The compositions of this document may be prepared by any conventional technique for preparing liquid cleaning compositions.

GB-A-2 181 738, which relates to a stable liquid detergent composition, discloses a range of water-insoluble abrasives, including some inorganic abrasives, and further mentions powders of plastics such as polystyrene, polyacrylate and nylon. However, all examples given use silica powder as the abrasives. This document does not disclose a method for preparing the detergent composition. The authors of this document were obviously unaware of the difficulty of preparing a stable aqueous dispersion of polymers such as polystyrene particles.

US-A-4 655 957, which relates to a composition which can be used as a cleaning agent for contact lenses without scratching the surface of the contact lens, proposes certain organic polymers which are hydrophilic in nature from the group consisting of poly(hydroxyalkyl methacrylate), poly(hydroxyalkyl acrylate), poly-N-vinyllactam or mixtures thereof.

A composition which meets the optimum requirements of a non-scratching, stable, effective and safe aqueous abrasive is not contained in the prior art. What is most important to the invention is the ability to remove most stains from all hard surfaces which are most commonly found, and in particular plastic surfaces, without damaging such delicate plastic materials as are found, for example, as kitchen countertops, non-stick coatings on metal pots, polystyrene, polymethyl methacrylate, polyvinyl chloride, nylon, polyester (e.g. fiberglass) and the like. In addition to removing stains, the composition should also have good degreasing properties. Physical stability is, as demonstrated by the state of the art listed above, a major problem and a prerequisite for good consumer acceptance.

Accordingly, it is an object of the present invention to provide a process for preparing a stable, liquid, aqueous, abrasive-containing cleaning composition which is safe and also substantially non-abrasive on the most commonly encountered surfaces, including plastic surfaces.

A further object of the invention is to provide the compositions produced by the process according to the invention.

Further tasks will become apparent later in the description.

Description of the invention

The object of the invention is achieved in accordance with the following description by a process for producing a stable, liquid, non-abrasive, aqueous, abrasive cleaning composition containing a fatty acid and/or fatty acid soap, an anionic surfactant that is not a soap, a non-ionic surfactant, an electrolyte and an abrasive in particulate form, as well as by the compositions obtained thereby.

The fatty acid component can be any fatty acid having a carbon chain of about 6 to 30, preferably 8 to 20 carbon atoms. Most preferred are C₁₀-C₁₈ fatty acids, with typical naturally occurring materials such as coconut oil, palm kernel oil and animal tallow oil being preferred as fatty acid sources. Most preferred fatty acids are C₁₂-C₁₈ fatty acids such as those found in coconut oil. A typical fatty acid composition of coconut oil contains about 50% C₁₂, 20% C₁₄, 8.5% C₁₆ and 10% C₁₈ fatty acids, the balance being other acids and possibly even some neutral material, and is liquid at 40°C. While the most common sources are natural oils or fats derived therefrom which provide mixed acids, it will be understood that the individual specific acids and also any mixture of any number of acids having chain lengths in the C₆-C₃₀ range may be used. The soaps used are alkali metal and ammonium salts, with sodium and potassium salts being preferred. The fatty acid may constitute about 0.5 to 15% by weight, preferably 1 to 10% by weight, and most preferably 1 to 7% by weight of the composition.

The anionic surfactants that are not soaps contain a linear aliphatic hydrocarbon chain with 10 to 20 carbon atoms and are selected from the group consisting of sulfonate and sulfate surfactants. These can consist of any common anionic surfactant, such as alkylbenzenesulfonates, alkyl sulfates, alcohol sulfates, alcohol ether sulfates, olefin sulfonates, paraffin sulfonates, fatty acid monoglyceride sulfates, taurides and the like in the form of their alkali and ammonium salts.

The preferred non-soap anionic surfactants are C₁₀-C₂₀ paraffin sulfonates, linear alkylbenzene sulfonates, and alcohol and alcohol ether sulfates.

Most preferred non-soap anionic surfactants are C₁₂-C₁₈ paraffin sulfonates in the form of their alkali metal or ammonium salts, C₁₂-C₁₆ alkylbenzenesulfonates, C₁₂-C₁₈ alkyl (i.e. alcohol) sulfates and the corresponding ether sulfates with 3 to 50 (e.g. 3, 5, 10, 20, 30 or 50) moles of condensed ethylene oxide. The most preferred salt-forming cation is Sodium. The amount of non-soap anionic surfactant is in the range of 1 to 15% by weight, preferably 1 to 10% by weight, and especially 1 to 5% by weight.

Some specific examples of suitable anionic surfactants are sodium lauryl sulfate, sodium paraffin (C14 to C17) sulfonate, sodium decyl sulfonate, sodium tridecyl sulfonate, sodium tallow alkyl sulfate, sodium coconut alkyl sulfate, sodium oxotridecyl (triethoxyl) sulfate (sulfated 3 E.O. condensate with oxotridecyl alcohol), sodium dodecylbenzene sulfonate, sodium tridecylbenzene sulfonate, sodium tetradecylbenzene sulfonate and sodium (C15) olefin sulfonate.

Nonionic surfactants that can be used herein contain an aliphatic hydrocarbon chain of 10 to 20 carbon atoms and have the molecular configuration of a hydrophobic compound condensed with ethylene oxide, with the number of oxyethyl groups in the nonionic surfactant ranging from 1 to 8. The hydrophobic compound can be, and is preferably derived from, an alcohol (preferably a C10-C16, typically a C13 alcohol such as linear tridecyl alcohol) or a polypropylene backbone. Other hydrophobic compounds such as thioalcohols, acids, amines and the like can also be used. The preferred alcohol is a C10-C16 alcohol containing from 1 to less than 5 moles of ethylene oxide, and preferably from 2 to 4 moles of ethylene oxide, typically 3 moles of ethylene oxide. The amount of nonionic surfactant in the formulation varies from about 0.5 to about 15% by weight, with preferred amounts ranging from 1 to 10% by weight, and more preferably from about 3.5 to 6.5% by weight; typically and most preferably, 5% by weight.

The electrolyte used here is typically an inorganic or organic builder-type alkali salt. The conventional salts include the alkali metal bicarbonates, borates, carbonates, phosphates, polyphosphates and silicates as inorganic Agents and polycarboxylates such as polyacetates, tartrates, citrates, maleates, oxydiacetates, alkenyl succinates, carboxymethyl oxysuccinates, oxydisuccinates and the like as organic agents. Polymer builder salts such as the water-soluble salts of maleic acid polymers, itaconic acid polymers and the like, as well as copolymers and interpolymers thereof with polymerizable α,β-ethylenically unsaturated compounds such as vinyl esters, esters, alkyl alcohols, acrylic and methacrylic acid and esters thereof, etc. can also be used.

The amount of electrolyte may vary over a wide range from as little as 0.5% to 25%. A preferred range is from about 2 to 15%; typically a mixture of carbonate and phosphate may give a total of 5 to 10%; other suitable and preferred mixtures may comprise carbonate, polyphosphate and optionally some silicate in amounts also of 5 to 10%.

Specific electrolytes include sodium and potassium carbonate, sodium and potassium bicarbonate, sodium and potassium sesquicarbonate, sodium and potassium orthophosphates, phyrophosphates, tripolyphosphates and hexametaphosphates, sodium and potassium tetraborate (anhydrous, pentahydrate and decahydrate), sodium silicate (e.g., sodium metasilicate or other silicates where the Na₂O:SiO₂ ratio is in the range of 3.5 to 1:1) as an example of inorganic materials and the tetrasodium or potassium salt of ethylenediaminetetraacetic acid, trisodium nitrilotiacetate, disodium polymaleate and the like as an example of organic materials.

The abrasive may be any particulate abrasive which is a solid polymer derived from polyethylene, polypropylene, polystyrene, polyester, polyvinyl chloride, polyvinyl acetate, polymethyl methacrylate and numerous copolymers and intermolecular polymers thereof. As a criterion for suitability, the material has a hardness not greater than homopolymeric methyl methacrylate and therefore does not scratch it, and has an average particle size in the range of 10 to 150 µm, preferably 25 to 100 µm and especially 30 to 75 µm e.g. 60 µm. For optimum effectiveness it is most desirable to use polyvinyl chloride abrasive powders having an average particle size of about 60 µm, with a larger amount being in the range of 30 to 75 µm. The molecular weight of the polymeric abrasives can vary over a wide range as long as the physical properties set out above are achieved. Generally, the molecular weights will have values of a few thousand (eg 2,000, 5,000, 20,000), a few hundred thousand (eg 125,000, 250,000, 400,000) and up to a few million (eg 1,000,000, 2,000,000, 4,000,000, 6,000,000). The amount of abrasive will be in the range of about 2 to 30% or more (eg 40%, 50%). A preferred range in the preferred formulations is from 5 to 25% and especially from 5 to 15%, such as 7%, 10% or 12%.

A variety of ingredients may optionally be included in the formulations of the invention. Some are even preferred, such as inorganic viscosity modifiers (e.g., milled clays such as bentonite, attapulgites, etc.), organic viscosity modifiers such as methylcellulose, carboxylmethylcellulose, and hydroxypropylmethylcellulose. Such materials are particularly advantageous for a "cream-like" abrasive where a "thickened" material is desired by the consumer. Such products may desirably have viscosities ranging from several hundred (250 mPas, 400 mPas, 500 mPas) to several thousand (e.g., 1100 mPas, 1500 mPas, 2000 mPas, etc.). It is extremely important that the formulations of the invention exhibit unusual stability (i.e., no or minimal phase separation) in the absence of "viscosity increasers," the primary function of which is predominantly thickening, as described above. The amount of viscosity modifier is in the range of 0.1 to 5 to 10%, usually 0.5 to 3%. Other optional but also preferred additives include a hydrocarbon material, particularly a terpene such as d-limonene. Such terpenes are readily available as a component of many perfume materials which are generally added to most consumer detergents. Amounts of the hydrocarbon may vary from 0.05 to 5% and preferably from 0.1 to 2 to 3%. Other additives which may be used include bleaching agents (liquid and solid hypochlorites, for example available as NaOCl solution or calcium hypochlorite powder, chloramine, chlorinated di- and trisodium phosphates, sodium and potassium dichloroisocyanurates, trichlorocyanuric acid, etc.), buffers, caustic soda, caustic potash, foam enhancers, enzymes, preservatives, disinfectants, dyes, fragrances and the like, and may be used when desired and compatible. Generally, smaller amounts of such additives are used, e.g. 0.01 to 10% and often 0.1 to 5%.

The compositions of the invention are alkaline and generally have a pH of about 10 to 12. It is necessary that the fatty acid be added to the formulation as a free acid and be simultaneously neutralized in situ, preferably with caustic soda (NaOH) or caustic potash (KOH), adjusting the pH to the desired value. A typical, preferred pH is 11 ± 0.5.

According to the process of the present invention, the compositions are prepared by adding the following compounds to water in a suitable mixer and homogenizer at a temperature of 50 to 80 ºC, e.g. 60 ºC, with stirring in the order given:

0.5 to 15% by weight of the composition of C₆ to C₃₀ fatty acid,

0.5 to 15% by weight of the composition of nonionic surfactant containing a linear aliphatic hydrocarbon chain with 10 to 20 carbon atoms and the molecular configuration a hydrophobic compound condensed with ethylene oxide, wherein the number of oxyethyl groups in the ionic surfactant is in the range of 1 to 8,

optionally 0.1 to 10% by weight of the composition of viscosity modifier,

2 to 50% by weight of the composition of particulate abrasive which is a solid polymer derived from polyethylene, polypropylene, polystyrene, polyester, polyvinyl chloride, polyvinyl acetate or polymethyl methacrylate, having a hardness no greater than that of homopolymeric methyl methacrylate and having an average particle size in the range of 10 to 150 µm, and

Alkali metal and/or ammonium base to neutralize the fatty acid,

the temperature of the mixture at this point is reduced to approximately room temperature and

0.5 to 25% by weight of the composition of electrolyte comprising water-soluble inorganic or organic alkali builder salt and then

1 to 15% by weight of the composition of anionic surfactant which is not a soap, contains a linear aliphatic C₁₀ to C₂₀ hydrocarbon chain and is selected from the group consisting of sulfonate and sulfate surfactants, and finally,

If desired, 0.05 to 5% of a hydrocarbon may be added. If a hydrocarbon is not to be used, a fragrance that does not contain hydrocarbons may simply be used. However, it has been found desirable to use hydrocarbon materials to achieve improved grease removal properties.

The following examples serve to illustrate the present invention without, however, intending to limit it.

Parts and percentages are parts or percentages by weight unless otherwise stated.

Example I

A formulation containing the following ingredients is prepared: % Active Ingredients Distilled coconut fatty acids C₁₃-alcohol and 3 moles of ethylene oxide White milled clay Polyvinyl chloride powder (PVC) (beads with an average particle size of 60 µm, produced by an emulsion polymerization process) Aqueous tetrapotassium pyrophosphate solution Potassium carbonate Granules, anhydrous C₁₄-₁₇-paraffin (Na) sulfonate 3.33 2.0 Perfume Tap water Balance

The composition was prepared as described above. To the formula weight of water was added at 60 ºC the fatty acid, the nonionic surfactant, clay, abrasive and caustic potash were added with vigorous stirring. After a uniform mixture was obtained, it was cooled to room temperature (20 ºC) and the remaining components were added (in the order given) with stirring. A creamy, stable product was obtained; the pH was about 11 and the viscosity about 1100 mPas.

Example II

Example I was repeated except that the following fatty acids were used instead of 2% distilled coconut fatty acid:

(a) Lauric acid 2%

(b) Palmitic acid 2%

(c) Coconut fatty acids 3%

(d) Coconut fatty acids 4%

(e) Lauric/Stearic acid (3:1) 3.5%

Example III

Example 1 was repeated using 5% sodium lauryl sulfate instead of sodium paraffin sulfonate.

Example IV

Examples I and III were each repeated replacing the TKPP and K2CO3 with 4% soda ash (anhydrous Na2CO3).

Example V

Each of the previous examples was repeated individually, where instead of 5% non-ionic surfactant

(a) 3% non-ionic surfactant

(b) 6% non-ionic surfactant

has been used.

The product of Example I was used in a standardized test procedure to determine the extent of scratching on a plastic surface. This was compared with two commercially available products. The procedure involves the use of a reciprocating sponge (Spontex) with 1 g of test product acting on a plastic plate, which is washed after 200 strokes and the gloss is compared with that of the original. The plate used had an initial gloss value of 79 which remained unchanged after testing with the product of Example I. The two commercially available products gave values of 72 and 73, showing that the commercially available materials cause some damage to the plate, while the composition of the invention does not.

Claims (8)

1. A process for preparing a stable, liquid, aqueous, non-abrasive, abrasive cleaning composition, which comprises: A) the following compounds are added to water at a temperature of 50 to 80 ºC with stirring in a suitable mixer and homogenizer in the indicated order: 0.5 to 15% by weight of the composition of C₆-C₃₀ fatty acid, 0.5 to 15% by weight of the composition of nonionic surfactant containing a linear aliphatic C₁₀₀-C₂₀₀ hydrocarbon chain and having the molecular configuration of a hydrophobic compound condensed with ethylene oxide, the number of oxyethyl groups in the nonionic surfactant being in the range of 1 to 8, optionally 0.1 to 10% by weight of the composition of viscosity modifier, 2 to 50% by weight of the composition of particulate abrasive which is a solid polymer derived from polyethylene, polypropylene, polystyrene, polyester, polyvinyl chloride, polyvinyl acetate or polymethyl methacrylate, having a hardness not greater than homopolymeric methyl methacrylate and having an average particle size in the range of 10 to 150 µm, and B) the temperature of the mixture at this point is reduced to approximately room temperature and C) 0.5 to 25% by weight of the composition of electrolyte, which comprises water-soluble, inorganic or organic alkali builder salt, and then 1 to 15% by weight of the composition of anionic surfactant which is not a soap, contains a linear aliphatic C₁₀-C₂₀ hydrocarbon chain and is selected from the group consisting of sulfonate and sulfate surfactants, and finally, if desired, 0.05 to 5% of a hydrocarbon may be added 2. The process of claim 1 wherein the fatty acid is a C8-C20 acid, the non-soap anionic surfactant comprises a C12-C18 linear aliphatic hydrocarbon, and the non-ionic surfactant comprises a C10-C16 linear aliphatic hydrocarbon. 3. A process according to any preceding claim, wherein the fatty acid is derived from coconut oil, the non-soap anionic surfactant is paraffin sulfonate, the non-ionic surfactant is C₁₀-C₁₆ alcohol containing 1 to less than oxyethyl groups, and the electrolyte comprises polyphosphate. 4. A method according to any preceding claim, wherein the abrasive is polyvinyl chloride. 5. A process according to any one of claims 1 to 4, wherein the hydrocarbon is terpene. 6. A process according to any one of claims 1 to 4, wherein the hydrocarbon is d-limonene. 7. Composition obtainable by the process according to any one of the preceding claims. 8. The composition of claim 7 wherein the amount of fatty acid soap is in the range of 1 to 5 wt%, the amount of anionic surfactant other than soap is in the range of 1 to 5 wt%, the weight of nonionic surfactant is in the range of 1 to 10 wt%, the amount of electrolyte is in the range of 5 to 10 wt%, and the amount of abrasive is in the range of 5 to 15 wt%.