WO2000068349A1

WO2000068349A1 - Solid detergent composition comprising aluminium oxide

Info

Publication number: WO2000068349A1
Application number: PCT/EP2000/004233
Authority: WO
Inventors: Nikhileshwar Mukherjee; Earla Saikumar
Original assignee: Unilever N.V.; Unilever Plc; Hindustan Lever Ltd
Priority date: 1999-05-11
Filing date: 2000-05-09
Publication date: 2000-11-16
Also published as: ID30549A; IN192087B; AU4920000A

Abstract

The invention provides solid, preferably shaped, cleaning compositions comprising: i) 5 to 40 % of a detergent active, preferably at least one anionic detergent active; ii) 10 to 85 % of abrasive materials, comprising aluminium oxide and preferably also one or more other abrasive materials; iii) at least 0.5 % of a particulate material with a minimum water absorptive capacity of 200 % of its own weight, preferably silica gel or precipitated or spray-dried silica. The invention also provides a process for cleaning dishes and cooking utensils which involves the step of applying thereto a cleaning composition described above.

Description

SOLID DETERGENT COMPOSITION COMPRISING ALUMINIUM OXIDE

Technical field :

The invention relates to a solid synergistic cleaning composition for cleaning hard surfaces. More particularly the compositions of the invention are especially, but not exclusively in the form of bars/shaped tablets useful for cleaning hard surfaces and manual dish washing.

Background and Prior art :

Commercial hard surface cleaning compositions typically comprise, one or more surfactants and a plurality of abrasive particles dispersed therein. Combinations of these together with electrolytes are generally used to form a structuring system as is well known in the art.

The conventional cleaning compositions for hard surface cleaning are formulated in the form of solids such as powders, granules, pastes and bars, and in the form of fluid formulations such as liquids and gels.

Cleaning compositions in the solid form are much cheaper than liquids because of low cost packaging and these are very popular forms for developing countries. Amongst the solid forms bars are gaining popularity and growing rapidly in the market of developing countries because of better value delivery. The product dosage in the solid form is easier, it avoids spillage and the product application can be better controlled. Cleaning compositions in the bar form are economically superior to other product forms and the dosage per swipe from the bar is highly controllable. Bars and tablets also do not get easily sogged in the presence of water and the active ingredients are not lost. Bars and tablets require less packaging material and because of the ease of application they are highly preferred over other forms of the same composition and are especially suitable for low cost markets of the developing countries. Such cleaning compositions in bar or tablet form are particularly suitable for cleaning dishes, pots, pans and other cooking utensils.

While the bar and tablet forms of hard surface cleaning compositions have advantages in themselves, compared to other forms, it has now been found that the use of aluminium oxide as an abrasive, preferably in combination with one or more other abrasives, significantly further enhances the performance of these products in terms of cleaning efficiency, lesser effort required for cleaning, economy in use and other user benefits.

Description of the Invention:

All percentages given below are by weight on the total composition, unless specifically mentioned otherwise. Thus, according to the invention there is provided a solid cleaning composition comprising:

• 5 to 40%. of a detergent active;

• 10 to 85%. of abrasive materials, comprising aluminium oxide and optionally one or more other abrasive materials;

• at least 0.5% of a particulate material with a minimum water absorptive capacity of 200% of its own weight.

Preferably the composition is in the form of a solid shaped article such as a tablet or bar.

Abrasives :

The invention is characterized in the use of aluminium oxide as an abrasive which, alone or in combination with one or more other abrasives, gives surprising user benefits. Preferably, aluminium oxide is used in combination with one or more other abrasives.

Aluminium oxide has also been found to improve the structure and firmness of the solid shaped compositions.

Aluminium oxide used in the present invention has average particle size in the range of 0.5 to 400 microns and a Mho hardness of between 8 to 9.5. The level of aluminium oxide present in the composition is preferably in the range of 2 to 40% of the composition. More preferably the aluminium oxide is present at levels of between 5 and 35%, even more preferably 10-30%. A maximum level of 20% is suitable in most circumstances. For the purpose of the invention commercially available aluminium oxide may be used, subject to the particle size and hardness requirements being met.

The other abrasives may be water soluble or water insoluble. Soluble abrasives are present in such excess to any water present in the composition that the solubility of the abrasive in the aqueous phase is exceeded and consequently solid abrasive exists in the composition.

Suitable other abrasives can be selected from: particulate zeolites, calcites, dolomites, feldspar, silicas, silicates, other carbonates, bicarbonates, borates, sulphates and polymeric materials such as polyethylene, polyvinyl chloride and polycarbonate.

Preferred other abrasives for use in the cleaning compositions, particularly bars, have a Mho hardness of 2 - 6 and one of the previous constraints for incorporation of abrasive material with higher hardness has been the inability to develop a balanced formulation which can deliver an increased level of abrasive properties without loosing or compromising on other user properties. Preferred average particle sizes for the abrasives fall in the range of 10-400 microns, with values of 25-400 microns, more particylarly 30-200 microns, being preferred. Preferred levels of total conventional abrasive, soluble and insoluble together, range from 4-83 wt% on product, preferably in the range 10-60 wt%, more preferably 15-60%, even more preferably 20-60%. Besides aluminium oxide, which is the essential abrasive component in the formulation, the most preferred conventional abrasives are calcium carbonate (as calcite) , mixtures of calcium and magnesium carbonates (as dolomite), sodium hydrogen carbonate, potassium sulphate, zeolite, feldspar, talc and silica.

Calcite, feldspar and dolomite and mixtures thereof are particularly preferred due to their low cost, suitable hardness and colour.

Detergent Actives :

The compositions according to the invention comprise detergent actives which are generally chosen from anionic, nonionic, cationic, zwitterionic and amphoteric detergent actives or mixtures thereof. Preferably the compositions contain at least one anionic detergent.

Suitable anionic detergent active compounds are water soluble salts of organic sulphates and sulphonates having in the molecular structure an alkyl radical containing from 8 to 22 carbon atoms, and a radical chosen from sulphonic acid or sulphur acid ester radicals and mixtures thereof.

Examples of suitable anionic detergents are sodium and potassium alcohol sulphates, especially those obtained by sulphating the higher alcohols produced by reducing the glycerides of tallow or coconut oil ; sodium and potassium alkyl benzene sulphonates such as those in which the alkyl group contains from 9 to 15 carbon atoms ; sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow and coconut oil ; sodium coconut oil fatty acid monoglyceride sulphates; sodium and potassium salts of sulphuric acid esters of the reaction product of one mole of a higher fatty alcohol and from 1 to 7 moles of ethylene oxide; sodium and potassium salts of alkyl phenol ethylene oxide ether sulphates with from 1 to 8 units of ethylene oxide and in which the alkyl radical contains from 4 to 14 carbon atoms; the reaction product of fatty acids esterified with isethionic acid and neutralised with sodium hydroxide where, for example, the fatty acids are derived from coconut oil, and mixtures thereof. The preferred water-soluble synthetic anionic detergent active compounds are the alkali metal (such as sodium and potassium) , alkaline earth metal (such as calcium and magnesium) or ammonium salts of higher alkyl benzene sulphonates and mixtures with olefin sulphonates and higher alkyl sulphates, and the higher fatty acid monoglyceride sulphates. The most preferred anionic detergent active compounds are higher alkyl aromatic sulphonates such as higher alkyl benzene sulphonates containing from 6 to 20 carbon atoms in the alkyl group in a straight or branched chain, particular examples of which are sodium salts of alkylbenzene sulphonates or alkyltoluene, -xylene or -phenol sulphonates, alkylnaphthalene sulphonates, ammonium diamylnaphthalene sulphonate, and sodium dinonylnaphthalene sulphonate. A specific type of anionic detergent which may also be used in the compositions according to the invention is the group of fatty acid soaps. The soap may contain from 8 to 22 carbon atoms. The soap may be obtained by saponifying a triglyceride and/or a fatty acid. The triglyceride may be fats or oils generally used in soap manufacture such as tallow, tallow stearines, palm oil, palm stearines, soya bean oil, fish oil, caster oil, rice bran oil, sunflower oil, coconut oil, babassu oil, palm kernel oil, and others. In the above process the fatty acids are derived from oils/fats selected from coconut, rice bran, groundnut, tallow, palm, palm kernel, cotton seed, soybean, castor etc.

Suitable nonionic detergent active compounds can be broadly described as compounds produced by the condensation of alkylene oxide groups, which are hydrophilic in nature, with an organic hydrophobic compound which may be aliphatic or alkyl-aromatic in nature. The length of the hydrophilic polyoxyalkylene radical which is attached to any particular hydrophobic group can be readily adjusted to yield a water- soluble compound having the desired balance between hydrophilic and hydrophobic elements. Particular examples include : • the condensation products of aliphatic alcohols having from 8 to 22 carbon atoms in either straight or branched chain configuration with 2-15 mol equivalents of ethylene oxide; condensation products of alkylphenols whose alkyl group contains from 6 to 12 carbon atoms with 5 to 25 mol equivalents of ethylene oxide;

• condensates of the reaction product of ethylenediamine and propylene oxide with ethylene oxide, the condensate containing from 40 to 80wt% of polyoxyethyleneoxy groups and having a molecular weight of from 5,000 to 11,000.

Other suitable nonionic detergent active compounds are: • tertiary amine oxides of structure R₃NO, where one group R is an alkyl group of 8 to 18 carbon atoms and the others are each methyl, ethyl or hydroxyethyl groups, for instance di ethyldodecylamine oxide;

• tertiary phosphine oxides of structure R₃PO, where one group R is an alkyl group of from 10 to 18 carbon atoms, and the others are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, for instance dimethyldodecylphosphine oxide;

• dialkyl sulphoxides of structure RS0 where the group R is an alkyl group of from 10 to 18 carbon atoms and the other is methyl or ethyl, for instance methyltetradecyl sulphoxide;

• fatty acid alkylolamides;

• alkylene oxide condensates of fatty acid alkylolamides.

Suitable amphoteric detergent-active compounds that can be employed are derivatives of aliphatic secondary and tertiary amines containing an alkyl group of 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic water-solubilizing group, for instance sodium 3-dodecyl- amino-propionate, sodium 3-dodecylaminopropane sulphonate and sodium N-2-hydroxydodecyl-N-methyltaurate .

Suitable cationic detergent-active compounds are quaternary ammonium salts having an aliphatic radical of from 8 to 18 carbon atoms, for instance dodecyl- and cetyl-trimethyl ammonium bromide and chloride.

Suitable zwitterionic detergent-active compounds that optionally can be employed are derivatives of aliphatic quaternary ammonium, sulphonium and phosphonium compounds having an aliphatic radical of from 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic water- solubilising group, for instance 3- (N-N-dimethyl-N- hexadecylammonium) -propane-1 sulphonate betaine, 3- (dodecylmethyl-sulphonium) -propane-1 sulphonate betaine and 2- (cetylmethylphosphonium) -ethane sulphonate betaine.

Further examples of suitable detergent-active compounds are compounds commonly used as surface-active agents given in the well-known textbooks "Surface Active Agents", Volume I by Schwartz and Perry and "Surface Active Agents and Detergents", Volume II by Schwartz, Perry and Berch. The total amount of detergent active compound to be employed in the detergent composition of the invention will preferably be from 1.5 to 25%, more preferably from 2 to 15% by weight . Water absorptive particulate:

The water absorptive particulate material preferably has a water absorptive capacity of between 200 and 300% of its own dry weight. Preferred materials are silica gel and precipitated or spray-dried silica. Most preferred is precipitated silica. The water absorptive material is preferably used in an amount of at least 3% of the total composition. The maximum amount is preferably 10%.

Optional Ingredients:

Other ingredients such as: detergency builders, fillers, structuring agents, solvents, perfumes, colouring agents, fluorescers, enzymes can also be used in the compositions. Preferably, the compositions comprise one or more fillers and/or structuring agents.

Builders:

They are preferably inorganic and suitable builders include, for example, alkali metal aluminosilicates (zeolites), sodium carbonate, sodium tripolyphosphate (STPP) , tetrasodium pyrophosphate (TSPP) , and combinations of these. Builders are suitably used in an amount ranging from 1 to 50%, preferably from 1 to 30%.

Fillers :

Fillers suitable for use in the compositions include kaolin, calcium carbonate (calcite) , talc, sodium sulphate, soapstone, china clay and the like, used singly or in combination, suitably in an amount ranging from 10 to 75%, preferably from 30 to 70%. Some of these materials may also function as abrasives, as outlined above.

Structuring agents:

The compositions according to the invention may contain polymeric structuring agents to aid in providing appropriate rheological properties and in enhancing their distribution and adherence of the composition to the hard surface to be cleaned. Preferred structuring agents include polysaccharides, such as sodium carboxymethyl cellulose and other chemically modified cellulose materials and other non-flocculating structuring agents such as biopolymer PS87 referred to in US patent No. 4 329 448. Certain polymers such as polymers of acrylic acid cross-linked with a poly- functional agent, for example CARBOPOL R, can also be used as structuring agents. The amount of such structuring agents, when employed, to be used in compositions according to the invention can be as little as 0.001%, preferably at least 0.01%. In general the composition of the invention can optionally comprise from 0.1-1% of polymer. The compositions may also contain inorganic structuring agents and sodium alumino silicates are particularly useful examples thereof. They may be prepared in situ in the bar from aluminium sulphate and alkaline silicate. Cleaning process

The the solid compositions according to the invention are particularly suitable for dishwashing purposes. The cleaning product either in powder or, preferably, in bar or tablet or any other shaped form can be directly applied to the dishes, pots, pans and other cooking utensils providing very efficient baked-on soil removal as well as grease cutting. Thus, the invention also provides a process for cleaning dishes and cooking utensils comprising the step of applying a solid composition according to the invention to the dishes and cooking utensils.

The invention will now be illustrated with respect to the following non-limiting examples.

Examples :

Example 1

Process for making bar 1 according to the invention: A batch of 20 kg was processed by conventional bar processing technology.

1.9 kg of sodium carbonate was mixed with 4.7 kg of linear alkyl benzene sulphonic acid in a sigma mixer. This was followed by additions of 4.8kg china clay, 0.6 kg of aluminium sulphate, 0.12 kg of silica, 1.8 kg of sodium silicate, 6.4 kg of aluminium oxide and other minor ingredients and water were added and mixed. The mixing was continued and followed by extrusion, billeting and stamping.

Examples 2 to 4

Using the same process, but using different abrasives at the same levels, bars (2 to 4) were prepared. In bar 2 the abrasive is calcite, in bar 3 it is dolomite and in bar 4 it is felspar. For ready reference the compositions of bars 1 to 4 are set out in Table 1.

Table 1

The cleaning efficiency of bars 1 to 4 on tough soil were compared and the results are presented in Table 2

Table 2

The data presented in table 2 shows that the use of aluminium oxide as an abrasive is significantly superior to the bars with other conventional abrasives.

The bar 1 with aluminium oxide as the abrasive was evaluated as to its performance in comparison with a conventional cleaning composition (a leading commercial dish wash bar) : Bar 5. The evaluation of performance was on the basis of cleaning efficiency in terms of economy, cleaning time and cleaning effort and effects on soaking. The tests were conducted by creating tough soil being charred milk (5ml) on stainless steel plates. The results are shown in table 3 with bars 1 and 5.

The economy aspect was determined by varying the product dosage by keeping the scrubbing pressure uniform at 3 Kgs . , scrubbing time at 5 minutes and uniform soak time. The performance in terms of the effort was determined by varying the pressure of scrubbing while keeping the product dosage, scrubbing time and soak time. In case of the efficiency in terms of faster cleaning the time was varied while keeping the effort , product dosage , scrubbing time and soak time constant. The performance in terms of soaking was determined by varying the soaking time while keeping the product dosage effort and scrubbing time at constant .

Table 3

A comparison of the results shown in table 3 clearly goes to show that bars according to invention (Bar 1) are superior in terms of performance.

The efficacy of the compositions according to the invention was also evaluated for cleaning tough soil by using different levels of aluminium oxide, in combination with other abrasives, in bars (6 to 9) and the results are shown in Table 4. Table 4

The data presented in table 4 shows efficient cleaning performance of bars 6 to 9 containing from 5 to 30 % aluminium oxide.

Claims

1. Solid cleaning composition comprising: i) 5 to 40%. of a detergent active; ii) 10 to 85%. of abrasive materials, comprising aluminium oxide and optionally one or more other abrasive materials; iii) at least 0.5% of a particulate material with a minimum water absorptive capacity of 200% of its own weight.

2. Solid shaped cleaning composition according to claim 1 characterised in that the amount of aluminium oxide is 2-40% and has an average particle size of 0.5-400 μ .

3. Composition according to claims 1 or 2 characterized in that it contains one or more other abrasives with an average particle size of 10-400 μm and in an amount of 4-83%.

4 Composition according to claim 3 characterized in that the abrasives are chosen from: zeolites, calcites, dolomites, feldspar, silicas, silicates, other carbonates, bicarbonates, borates, sulphates and polymeric materials.

5. Composition according to claims 1-4 characterized in that it contains an anionic detergent selected from water soluble salts of organic sulphates and sulphonates having in the molecular structure an alkyl radical containing from 8 to 22 carbon atoms, and a radical chosen from sulphonic acid or sulphur acid ester radicals and mixtures thereof.

6. Composition according to claims 1-5 characterized in that the water absorptive particulate material has a water absoptive capacity of between 200 and 300% of its own weight and is chosen from silicagel and precipitated and spray-dried silica.

7. Composition according to claims 1-6 characterized in that it also contains a polymeric and/or inorganic structuring agent.

8. Composition according to claims 1-7 characterized in that it is a solid shaped article.

Process for cleaning dishes and cooking utensils comprising the step of applying to the dishes or cooking utensils a solid composition comprising: i) 5 to 40%. of a detergent active; ii) 10 to 85%. of abrasive materials, comprising aluminium oxide and optionally one or more other abrasive materials; iii) at least 0.5% of a particulate material with a minimum water absorptive capacity of 200% of its own weight.