An abrasive cleaning composition

Abstract

The invention relates to an abrasive cleaning composition. It is especially useful in cleaning surfaces in the kitchen and utensils soiled with burnt and oily stains. It is also seen to minimize malodour on surfaces cleaned with the inventive composition. This is achieved by including an amphoteric surfactant and select chelating agent in a cleaning composition comprising calcium and magnesium LAS based surfactant.

Description

[0001] AN ABRASIVE CLEANING COMPOSITION

[0002] Field of the Invention

[0003] The invention relates to an abrasive cleaning composition. It is especially useful in cleaning surfaces in the kitchen and utensils soiled with brunt and oily stains. It is also seen to minimize malodour on surfaces cleaned with the inventive composition.

[0004] Background of the Invention

[0005] Hard surface cleaning compositions especially used for dishwashing typically comprise one or more surfactants and a plurality of abrasives dispersed therein. Surfactants used are generally of the anionic form. An especially preferred anionic surfactant for such use is sodium salt of linear alkyl benzene sulphonate (NaLAS). The present applicant in the past have a patent granted as IN204326 for use especially in dishwashing by hand preferably in the form of a bar which comprises a then novel surfactant prepared by neutralization of LAS with dolomite in predominantly solid form. Dolomite which is mostly CaMg(CC>3)2 reacts with LAS to form the Calcium and Magnesium salt thereof. Such a surfactant has been found to be very effective to formulate bars for hand dishwashing, the formulation further including abrasives like calcite, china clay and dolomite. Such bars also contain a small amount of sodium salt of LAS which may be formed insitu if the composition includes sources of sodium like sodium carbonate and sodium silicate and sufficient amount of water.

[0006] The technology in the abovementioned cleaning composition has been commercialized by the present applicants in the form of a hand dishwash bar. The present inventors in an effort to further improve the cleaning efficacy conducted various experiments before they arrived at the present invention. They found that when an amphoteric surfactant and a chelating agent were added to the cleaning composition comprising a calcium and magnesium LAS surfactant and abrasives, exceptional improvement in cleaning efficiency especially with respect to burnt stains and oily residues, found on used kitchen utensils, was obtained. It was further observed that such a composition also delivered enhanced anti-malodour benefits.

[0007] It is thus an object of the present invention to provide for an abrasive cleaning composition that delivers improved cleaning efficacy against burnt and oily stains especially on used kitchen utensils and other surfaces in the kitchen. Summary of the Invention

[0008] The first aspect of the present invention relates to an abrasive cleaning bar composition comprising

[0009] (i) 1 to 25 wt% anionic surfactant comprising calcium salt of linear alkyl benzene sulphonate (CaLAS) and magnesium salt of linear alkyl benzene sulphonate (MgLAS);

[0010] (ii) 30 to 70 wt% abrasive particle;

[0011] (iii) 0.05 to 2 wt% amphoteric surfactant;

[0012] (iv) 0.05 to 2 wt% chelating agent selected from one or more of trisodium methyl glycine diacetate (MGDA), L-glutamic acid N, N-diacetic acid tetrasodium (GLDA), sodium gluconate, capryl hydroxamic acid (CHA), elthylenediamine - N, N’-disuccinic acid (EDDS); Iminodisuccinic acid (IDS), polyaspartic acid, gluconolactone and piroctone olamine; and

[0013] (v) an alkaline pH adjusting agent; wherein the composition has a pH in the range of 9 to 12; and wherein the amphoteric surfactant is an amine oxide or a betaine surfactant.

[0014] Another aspect of the present invention relates to a method of cleaning a surface comprising the step of applying a composition of the first aspect preferably diluted with water followed by the step of rinsing said surface with water.

[0015] Detailed Description of the Invention

[0016] Any feature of one aspect of the present invention may be utilized in any other aspect of the invention. The word “comprising” is intended to mean “including” but not necessarily “consisting of” or “composed of.” In other words, the listed steps or options need not be exhaustive. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and / or use are to be understood as modified by the word “about”. Numerical ranges expressed in the format " x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "x to y", it is understood that all ranges combining the different endpoints are also contemplated. Unless specified otherwise, amounts as used herein are expressed in percentage by weight based on total weight of the composition and is abbreviated as “wt%”. The use of any and all examples or exemplary language e.g. “such as” provided herein is intended merely to better illuminate the invention and does not in any way limit the scope of the invention otherwise claimed. Room temperature is defined as a temperature of about 25 degree Celsius. Hard surfaces which may be cleaned with the composition of the invention are those which are used for cooking and areas around it. They include floors, walls, tiles, windows, cupboards, stoves, oven and sinks in the kitchen and utensils used for cooking. Utensils include vessels like glasses, pots, pans, baking dishes and flatware made from ceramic, china, metal, glass, plastic (polyethylene, polypropylene, polystyrene), wood, enamel, Inox®, teflon, or any other material commonly used in the making of articles used for eating and / or cooking. It also includes household appliances like refrigerators, freezers, washing machines, automatic dryers, ovens, microwave ovens and dishwashers.

[0017] The cleaning composition of the present invention comprises calcium salt of linear alkyl benzene sulphonic acid (abbreviated as Ca-LAS). Ca-LAS is formed by neutralising linear alkyl benzene sulphonic acid (LAS acid) with a calcium salt. Preferably the calcium salt is calcium hydroxide or calcium oxide. Ca-LAS works as primary surfactant in the composition for cleaning benefit. It is preferred that the composition according to the present invention comprises 0.1 to 15 wt% of calcium salt of linear alkyl benzene sulphonic acid, more preferably 0.5 to 10 wt%.

[0018] Similarly the composition comprises magnesium salt of linear linear alkyl benzene sulphonic acid (abbreviated as Mg-LAS). Mg-LAS is formed by neutralising linear alkyl benzene sulphonic acid (LAS acid) with a magnesium salt. Preferably the magnesium salt is magnesium hydroxide or magnesium oxide. Mg-LAS works as primary surfactant in the composition for cleaning benefit. It is preferred that the composition according to the present invention comprises 0.1 to 15 wt% of magnesium salt of linear alkyl benzene sulphonic acid, more preferably 0.5 to 10 wt%. When the Ca-LAS and the Mg-LAS are separately prepared or sourced and mixed during the preparation of the composition of the invention, it is preferred that they are mixed such that the weight ratio of CaLAS: Mg: LAS is in the range of 3:1 to 1 :3 preferably in the range of 2:1 to 1 :2.

[0019] An especially preferred aspect of the present invention relates to preparing a mixture of Ca-LAS and Mg-LAS by reacting LAS with dolomite. Dolomite is a naturally occurring mineral and sometimes varies in its specification, particularly in the relative ratio of components therein.

[0020] The minerals that belong to the dolomites group are Ankerite Ca(Fe, Mg, Mn) (C03)2, Benstonite (Ba, Sr)e(Ca, Mn)eMg(C03)3, Dolomite CaMg(C03)2or Huntite CaMg3(C03)4. The basic anionic (negatively charged) unit of this class consists of a triangle where at the centre resides a carbon atom. At every corner of the triangle sits an oxygen atom. The threefold symmetry of the triangle explains the trigonal symmetry that many members of this class possess. The structure of the dolomites group of minerals is layered in such a way that the "A" metal ions occupy one layer which is followed by a carbonate layer which is followed by the "B" metal ion layer followed by another carbonate layer, etc. The layering structure may be depicted as

[0021] A|CO3|B|CO3|A|CO3|B|CO3

[0022] In Dolomite the A and B ions are Ca and Mg which have the largest ionic radius differential of the group. If the A and B ions are close in radius, they tend to not segregate as easily as its A and B layers, which is required to form this structure and therefore these minerals. With the selective use of anionic surfactant that has been neutralised using one or more minerals from the dolomites group thereby resulting in a dolomite salt of the corresponding anionic surfactant (e.g: neutralisation of linear alkyl benzene sulphonic acid (LAS acid) resulted in dolomites-LAS which is being referred to herein as Do-LAS. It has been found that the weight ratio of Ca-LAS to Mg-LAS in Do-LAS is very close to 1 : 1 and is often in the range of 1 :2 to 2: 1.

[0023] The anionic surfactant comprising Ca-LAS and Mg-LAS is included in 1 to 25 wt% preferably 5 to 20 wt% of the composition. It is preferred that the anionic surfactant may additionally comprise sodium salt of linear alkyl benzene sulphonic acid (Na-LAS), alpha-olefin sulphonate (AOS) or mixtures thereof. When included or formed in-situ Na-LAS is preferably present in 1 to 10 wt% of the composition. It is possible that Na-LAS is intentionally included into the composition. Alternately Na-LAS may form insitu during manufacture and storage of the composition by reaction of one or more salts or compounds present with a sodium cation in the presence of water like sodium carbonate, sodium silicate etc. When AOS is preferably externally included in the composition, it is in an amount in the range of 1 to 5 wt%.

[0024] An abrasive particle is included in the composition according to the present invention. An abrasive particle is a particulate matter which is insoluble in water. In the alternative, the abrasive may be partially soluble and 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. Preferred abrasives for use in general purpose compositions have a Moh hardness 2-7 although higher hardness abrasives can be employed for specialist applications. Preferred average particle sizes for the abrasive fall in the range 0.5-400 microns preferably 10-200 microns.

[0025] The composition of the invention preferably includes abrasives which are selected from one or more of particulate zeolite, alumina, clay, calcium carbonate e.g. calcite, dolomite, feldspar, silica, silicate, alumina, bicarbonate, borate, sulphate and polymeric materials such as polyethylene. More preferred abrasive particle is selected from one or more of clays, calcium carbonate, dolomite, silica, silicate, alumina and zeolite. Further more preferred abrasive particle for inclusion in the composition of the invention are one or more of a clay e.g. china clay, calcium carbonate, dolomite, silica, and sodium silicate.

[0026] Abrasive particle is included in 30 to 70 wt% of the composition. The most preferred abrasive particles when included in the composition of the invention are in the following concentration ranges: china clay (from 5 to 20 wt%), calcium carbonate (from 10 to 30 wt%), dolomite (from 5 to 20 wt%) and sodium silicate available usually as a 45% solution (from 1 to 5 % on dry weight basis of the composition).

[0027] The composition as per the invention further comprises an amphoteric surfactant selected form an amine oxide or a betaine surfactant. Preferably, the amphoteric surfactant is selected from one or more of alkyl amine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sulfobetaines (sultaines), the term “alkyl” being used to include the alkyl portion of higher acyl radicals. The betaine surfactant is preferably an alkyl amidopropyl betaines, even more preferably cocoamidopropyl betaine (CAPB). Amphoteric surfactant is included in an amount ranging from 0.05 to 2 wt%, more preferably from 0.1 to 2 wt% of the composition.

[0028] The composition of the invention includes a chelating agent which is preferably biodegradable. Biodegradable chelating agents are also referred to as green chelating agents. They degrade easier compared to conventional chelating agents in the waste streams after use of the composition in cleaning the desired surfaces. Preferred chelating agents as per the present invention are selected from one or more of trisodium methyl glycine diacetate (MGDA), L-glutamic acid N, N-diacetic acid tetrasodium (GLDA), sodium gluconate, capryl hydroxamic acid (CHA), elthylenediamine - N, N’-disuccinic acid (EDDS); Iminodisuccinic acid (IDS), polyaspartic acid, gluconolactone and piroctone olamine. Of these the more preferred agents are one or more of MGDA, GLDA, sodium gluconate and CHA, further more preferred agents are one or both of MGDA and GLDA, most preferably MGDA. The chelating agent is included in 0.05 to 2 wt% preferably 0.1 to 2%, more preferably 0.1 to 1.5% by weight of the composition. Without wishing to bound by theory the inventors believe that the combination of amphoteric surfactant and the chelating agent in the composition of the invention work to deliver improved cleaning of burnt and oily stains by way of impacting wetting properties.

[0029] The composition of the invention comprises an alkaline pH adjusting agent. The alkaline pH adjusting agent is preferably selected from one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide or combinations thereof. Preferred alkaline pH adjusting agent is sodium carbonate. When included sodium carbonate is preferably included in about 5 to 15 wt%. The pH of the composition is in the range of 9 to 12 preferably 9.5 to 11 .5.

[0030] The composition of the invention is in the form of a bar. The dish washing cleaning bar composition of the invention preferably has water in the range of 1 to 15 wt%, preferably in the range of 3 to 10 wt%.

[0031] The present invention also relates to a method of cleaning a surface comprising the step of applying the composition of the invention preferably diluted with water followed by the step of rinsing said surface with water. The surface for cleaning are those used for cooking and areas around it. They include floors, walls, tiles, windows, cupboards, stoves, oven and sinks in the kitchen and utensils used for cooking. It also includes household appliances like refrigerators, freezers, washing machines, automatic dryers, ovens, microwave ovens and dishwashers.

[0032] Preferably the surface is a hard surface in the kitchen including utensils. The invention will now be illustrated with the help of the following non-limiting examples.

[0033] Examples

[0034] Dishwash compositions in the form of bars as shown in Table - 1 were prepared using the following procedure:

[0035] The reaction and mixing were carried out in a Sigma mixer. The ingredients (amount indicated in wt% on dry weight basis) were added in the sequence as given in the table - 1. Each ingredient was added followed by mixing for 1 to 2 minutes before adding the next ingredient. The temperature was maintained around 75 °C. The mass mixed in the sigma mixer was then extruded through a plodder, cut into bars and stamped.

[0036] Table -1

[0037] The above bar compositions of Example A and 1 were then used to measure the following attributes: malodour score, % stain removal of burnt oil stain and % stain removal of burnt ghee stain. % stain removal of burnt oil and % stain removal of burnt ghee was measured using the following procedure:

[0038] Dehydrogenated castor oil I ghee were applied on to stainless steel plates. The stains were burnt in hot air oven for one hour at 110 °C. The plates were cooled and a WIRA automated instrument was used for cleaning. The % stain removal was measured using gravimetry and the average value over two sample plates is reported in the Table - 2 below.

[0039] The cleaned plates were sniffed by a trained panel of 11 members. They were scored on a scale of 0 to 5 with 5 being the maximum malodour and 0 being no malodour. The average malodour score is given in Table - 2 below.

[0040] The summary of the measurements is shown in Table -2. Table - 2:

[0041] The data in Table -2 above indicates that the composition as per the invention (Example -1) is vastly superior to a conventional dishwash bar (Example A) in all of the attributes tested.

Claims

Claims1. An abrasive cleaning bar composition comprising(i) 1 to 25 wt% anionic surfactant comprising calcium salt of linear alkyl benzene sulphonate (CaLAS) and magnesium salt of linear alkyl benzene sulphonate (MgLAS);(ii) 30 to 70 wt% abrasive particle;(iii) 0.05 to 2 wt% amphoteric surfactant;(iv) 0.05 to 2 wt% chelating agent selected from one or more of trisodium methyl glycine diacetate (MGDA), L-glutamic acid N, N-diacetic acid tetrasodium (GLDA), sodium gluconate, capryl hydroxamic acid (CHA), elthylenediamine - N, N’-disuccinic acid (EDDS); Iminodisuccinic acid (IDS), polyaspartic acid, gluconolactone and piroctone olamine; and(v) an alkaline pH adjusting agent; wherein the composition has a pH in the range of 9 to 12; and wherein the amphoteric surfactant is an amine oxide or a betaine surfactant.

2. A composition as claimed in claim 1 wherein the weight ratio of CaLAS: Mg: LAS is in the range of 3:1 to 1 :3 preferably in the range of 2:1 to 1 :2.

3. A composition as claimed in claims 1 or 2 wherein the anionic surfactant additionally comprises sodium salt of linear alkyl benzene sulphonate (NaLAS), alpha olefin sulphonate (AOS) or mixtures thereof.

4. A composition as claimed in claim 3 comprising 1 to 10 wt% NaLAS.

5. A composition as claimed in claim 3 or 4 comprising 1 to 5 wt% AOS.

6. A composition as claimed in any one of the preceding claims wherein the abrasive particle is selected from one or more of clays, calcium carbonate, dolomite, silica, silicate, alumina and zeolite.

7. A composition as claimed in any one of the preceding claims wherein the betaine surfactant is coco amido propyl betaine. (CAPB).

8. A composition as claimed in any one of the preceding claims wherein the alkaline pH adjusting agent is sodium carbonate, sodium bicarbonate, sodium hydroxide or combinations thereof.

9. A composition as claimed in any one of the preceding claims comprising 1 to 15 wt% water.

10. A method of cleaning a surface comprising the step of applying a composition as claimed in any one of the preceding claims preferably diluted with water followed by the step of rinsing said surface with water.

11. A method as claimed in claim 10 wherein the surface is a hard surface in the kitchen including utensils.

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