EP2920291B1

EP2920291B1 - Surface cleaning composition

Info

Publication number: EP2920291B1
Application number: EP13773744.1A
Authority: EP
Inventors: Carlo Johannes van den BERGH; Neeraj Gupta; Paolo Mondani; Giovanni Taino
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2012-11-16
Filing date: 2013-10-07
Publication date: 2018-02-21
Anticipated expiration: 2033-10-07
Also published as: EP2920291A1; WO2014075845A1; BR112015009996A2; TR201802780T4; ZA201503399B; EA027538B1; CN104822819A; EA201500542A1

Description

Technical Field of the Invention

The present invention relates to granulated surface cleaning compositions, their manufacturing process and a method to clean surfaces using such compositions.

Background

Surfaces in the home and/or place of work are usually cleaned using liquid compositions to remove stains and/or soil. Examples are table-tops, leather, ceramic tiles on floors and bathroom walls, dish surfaces, car and vehicle surfaces. It is important that surfaces in and around the home/ place of work are properly cleaned on a regular basis to maintain a healthy living environment. For example, the presence of dirt, such as food residue, may lead to outgrowth of pathogenic microorganisms on the surfaces, such as floors and dishes. Such surfaces may subsequently bring a person into contact with pathogens, either directly by touching or indirectly (e.g. via food) and negatively affect health.
In addition, depending on the materials of which they are made, long-term exposure of certain surface materials to dirt may accelerate the formation of rust and other processes which may negatively affect the quality of such surfaces. For example cooking utensils which have become rusted, such as rusted pots, pans, forks and knives are typically regarded as unsuitable for use in cooking.
Therefore the cleaning of surfaces in and around the home and/or place of work is a common practice all over the world.
Typically the cleaning of surfaces, such as floors (e.g. mopping) or dishwashing, involves the use of water. This is practical in environments and at times where there is access to cheap and clean water. However in some parts of the world access to sufficient volumes of cheap and clean water may be problematic. For example, droughts, limited rainfall and/or pollution may limit access to cheap and clean water.
In some countries, the inhabitants have devised cleaning practices which require little or no water. An example is the use of 'abu rub' or 'abu rubbing' for cleaning. Abu rub comprises burnt waste or ash from plant material, such as the husk of rice. The abu rub is rubbed onto cooking instruments which improves the detachment of food residue on the instrument surface. Thereafter the mixture of abu rub and food residue is removed, for example by scrapping, wiping with a cloth or a little water.
However, using ash for surface cleaning may lead to unsatisfactory results. For example, it may not completely clean the surfaces and/or require a large amount of effort (e.g. rubbing) to provide a cleaning effect.
GB 1911/19,841 discloses a preparation for cleaning tin plates and the like. The preparation comprises of a mixture of calcium sulphate and sawdust. The preparation cleans grease and dirt from the surface of plates and leaves a brilliant finish. Further, the dust arising from the use of the composition in the cleaning machine is reduced considerably.
FR 2 881 142 A1 discloses a vegetal absorbing particles material used as cleaning agent wherein the vegetal absorbing material has an average particle size of from 0.350 to more than 0.700 mm.
It is an object of the present invention to provide a cleaning composition with an improved surface cleaning efficiency, and which is suitable for use in a cleaning method which requires little or no added water.
It is a further object of the present invention to provide a cleaning composition which can improve the surface cleaning efficiency of ash, and which is suitable for use in a cleaning method which requires little or no added water.
It is desirable to stimulate mixing of the cleaning composition with ash by the users to reduce the consumption rate of the composition and thus affordable (i.e. cheaper in use) for more people.
Therefore, it is a further object of the present invention to provide a cleaning composition which can be mixed with a substantial amount of ash with little or no loss of surface cleaning efficiency.

Summary of the invention

We have surprisingly found that one or more of the above objectives is achieved by a granular composition comprising a polyacrylic acid based swellable polymer, cellulose fiber and water.
Therefore, in one aspect the invention relates to a granular surface cleaning composition according to claim 1.
It was observed that the granular composition according to the invention can be used to efficiently clean surfaces, with little or no use of added water. In addition the composition can optionally be mixed with ash to improve the surface cleaning efficiency of the ash, compared to the cleaning efficiency of the ash alone. Furthermore it was found that mixing said composition with a substantial amount of ash (e.g. 50 wt. %) has little or no negative impact on the surface cleaning efficiency, compared to the cleaning efficiency of the granular composition alone.
Therefore in another aspect the invention relates to a cleaning mixture comprising at least 25 wt. %, of the granular composition, according to any one of claims 1 to 12, and at most 75 wt. % of ash.
The composition alone, or when admixed with ash, is suitable for cleaning surfaces in a method requiring little or no added water.
Therefore in another aspect the invention relates to a surface cleaning method comprising the steps of:

a) applying the granular composition of the invention and optionally ash to a surface;
b) optionally agitating the granules on the surface;
c) removing the applied material at step 'a' without using added water, such as by brushing.

Detailed description of the invention

In the context of the present invention, the expressions "soil" and "stain" as used herein generally comprise all kinds of soils and stains generally encountered in the household, either of organic or inorganic origin, whether visible or invisible to the naked eye, including soiling solid debris and/or with bacteria or other pathogens. The term 'soil' includes stubborn soil, which means strongly adhering soils that are typically very difficult to remove, such as burnt-on and/or baked-on food residues. Weight percentage (wt. %) is based on the total weight of the composition unless otherwise stated. The composition according to the invention is a granular composition, by which is indicated that it is powder-like.
By home or place of work (e.g. office) surface is meant any kind of surface typically found in and around houses like kitchens, bathrooms, e. g. (hard) floors, carpets, walls, tiles, windows, cupboards, sinks, showers,shower plastified curtains, wash basins, WCs, fixtures and fittings and the like made of different materials like ceramic, vinyl, no-wax vinyl, linoleum, melamine, glass, Inox, Formica, vitroceramic, any plastics, plastified wood, metal or any painted or varnished or sealed surface and the like. Home or place of work surfaces also include household appliances including, but not limited to refrigerators, freezers, washing machines, automatic dryers, ovens, microwave ovens, dishwashers and so on. Such hard surfaces may be found both in private households as well as in commercial, institutional and industrial environments. Home or office hard surfaces include dish surfaces. With dish surfaces is meant herein dishes, glasses, pots, pans, baking dishes and flatware made from ceramic, china, metal, glass, plastic (polyethylene, polypropylene,polystyrene, etc.), wood, enamel, Inox, Teflon, or any other material commonly used in the making of articles used for eating and/or cooking.
An improved cleaning (efficiency) can be indicated by the removal of soil and/or stains from hard surfaces by a lower effort (e.g. less wiping actions, less force per wiping action or a combination thereof) necessary to reach a similar level of stain/soil removal. For example, less effort would be required to remove a certain amount of soil from a metal surface. Clearly, an improved cleaning (efficiency) may also be indicated by a similar effort to remove an increased amount of soil/stain.

Granular form

The composition of the present invention comprises granules, wherein the average granular size is from 0.05 to 5 millimeter, preferably from 0.06 to 3, more preferably from 0.07 to 2 and even more preferably from 0.1 to 1 millimeter. Said average granular sizes have several advantages. First of all it reduces the development of dust during the dry hand dishwashing. Secondly, the granular form promotes cleaning by physical abrasion of the cooking instruments. Thirdly, the granular form facilitates the optional mixing with the ash.
In the context of the present invention, an average particle diameter is generally expressed as the d_3,2 value, which is the Sauter mean diameter, unless stated otherwise. The Sauter mean diameter is the diameter of a sphere that has the same volume/surface area ratio as a particle of interest. In case of fibrous material of which the cross-section may not be completely circular, the diameter of the fiber as expressed herein is the diameter of a circle having the same surface area as the cross-section of the fiber. Also the d_4,3 value, which is the volume weighted mean diameter, may be used herein. The volume based particle size equals the diameter of the sphere that has same the same volume as a given particle.
The composition according to the invention may comprise one or more composite granules, one or more single-component granules or any combination thereof. For example, the composition may comprise granules, wherein an individual granule comprises water swellable polymer, cellulose and water (i.e. composite granules). For example, the composition may comprise a mix of separately granulated swellable polymer, and cellulose (i.e. mix of single-component granules). It will be appreciated that water will typically be contained in granules and not form single component granules unless in extreme conditions, such as below freezing temperatures.
The individual granules according to the invention may have any suitable form to promote abrasive action. Preferably the granules are irregular in size and shape and have sharp surface edges.

Polyacrylic acid based water swellable polymer

The granular cleaning composition according to the invention comprises polyacrylic acid based water swellable polymer. The term polyacrylic acid based water swellable polymer is defined as polymers which are formed at least partially from acrylic acid monomers. The term acrylic acid encompasses salt derivatives such as acrylate. The molecular structure of polyacrylic acids may contain non-acrylic acid monomers, such as acrylamide monomers. Copolymers of acrylamide and polyacrylic acid are also encompassed by the term polyacrylic acid. However, preferably at least 40 wt. %, more preferably at least 60 wt. %, even more preferably 70 wt. % and still more preferably at least 90 wt. % of the weight of the polymer is derived from acrylic acid monomers. It will be appreciated that with the 'weight of the polymer' is meant the molecular weight of the polymeric molecule, which does not include the weight of any non-covalently bound material such as absorbed water molecules.
The polymer according to the invention may comprise a homogeneous polyacrylic acid mixture comprised of one type of poylacrylic acid only. Alternatively, the cleaning material may comprise a combination of poylacrylic acid types.
The polymer molecules of the polymer according to the invention may have the same or a varying chain length/ molecular weight. The average molecular weight of the polyacrylic acids preferably is from 10, 000 to 50, 000, 000 Daltons, more preferably from 1, 000, 000 to 25, 000, 000 Daltons and even more preferably from 5, 000, 000 to 20, 000, 000 Daltons.
The polymers according to the invention may be (partially) cross-linked. Cross-linking can be carried out by contacting the polymers with a suitable cross-linker, which is typically an organic molecule containing two or more double bounds. Examples of suitable cross-linkers are tetraallylethoxy ethane, 1,1,1-trimethylolpropanetricrylate and N,N'-methylenebisacrylamide.
Increasing the degree of cross-linking improves the absorption capacity against pressure; and decreasing the degree of cross-linking improves the swelling capacity.
Preferably the polymer according to the invention is partially cross-linked and more preferably comprises 0.1 to 2 wt. %, even more preferably 0.2 to 1 wt. % and still even more preferably 0.3 to 0.8 wt. % of cross-linker, based on the total weight of the final polymer. For example, polymer 'comprising 0.5 wt. % of cross-linker' indicates that 0.5 wt. % of cross-linker was consumed in the process of cross-linking the polymer (i.e. and built into the polymer network).
Preferably the cross-linker comprised by the polymer according to the invention is N,N'-methylene bisacrylamide.
Polymers according to the invention may be (partially) neutralized, which affects the charge density (ionicity) of the polymer. Neutralization can be carried out by contacting the polymer with a neutralizing agent, such as sodium carbonate or sodium hydroxide.
Preferably the polymers according to the invention are partially cross-linked and partially neutralized.
Preferably the polymer according to the invention has a five-minute absorbency under load (AUL) of at least 10 g/g, more preferably of at least 15 g/g, even more preferably of at least 18 g/g, still even more preferably of at least 21 g/g. The five-minute absorbency under load is determined according to the method described in US 5,149,335 which is hereby incorporated by reference.
Polyacrylic acids which may be used in the cleaning composition according to the invention are commercially available. For example under the trade name Aquasorb 3005 (SNF FLOERGER), Stockosorb, FAVOR (EVONIK industries); Water Lock A-180', A- 220, B-204, G-404, G-504, G-580 (Grain Processing); Acusol 771, 772 (Rohm & Haas); Luquasorb 1280, L74 SAP (BASF); Sorbfresh 220, Lysorb 218, ActyFill 20 (ADM Lysac); 432776, 436364, 435325 (Sigma Aldrich); Petrolsorb (Watersorb) and Disintex 200 (ISP).
The granular surface cleaning composition according to the invention comprises from 0.2 to 12 wt. % of polyacrylic based swellable polymer, preferably from 0.5 to 8 wt. % and even more preferably from 1 to 5 wt. %.

Cellulose fiber

The cellulose fibers (the terms 'cellulose fiber' and 'cellulose fibers' are used interchangeably) according to the invention can be plant-derived. Cellulose fibers are believed to principally consist of linear chains of Beta-linked D-glucose units. Common sources of cellulose fibers are cotton, bamboo silk, milled corn cobs or wood pulp (e.g. saw dust). Wood pulp is typically derived from softwood trees such as spruce, pine, fir, larch, hemlock or hardwoods such as eucalyptus, aspen and birch and in particular is typically made from the heartwood and the sapwood (e.g. and typically not from the bark). The process to manufacture pulp is known to the person skilled in the art and may involve mechanical, semi-mechanical and/or fully chemical methods. The manufacturing procedure of the plant pulp may influence the amount of lignin and hemicelluloses in the plant pulp. The pulp may be bleached or non-bleached.
Preferably the cellulose fiber according to the invention has an average fiber length of from 10 to 5,000 micron (µm), more preferably from 25 to 2,500 micron and even more preferably from 50 to 500 micron.
Preferably the cellulose fiber according to the invention has an average fiber thickness of from 2 to 200 micron (µm), more preferably from 5 to 100 micron and even more preferably 10 to 50 micron.
The granular surface cleaning composition according to the invention comprises from 10 to 80 wt. % of cellulose fiber, preferably from 20 to 75 wt. %, more preferably from 30 to 70 wt. %, even more preferably from 40 to 65 wt. %.
Preferably the cellulose fiber according to the invention have an oil absorbing capacity of at least 5 w/w, more preferably of at least 7 w/w, even more preferably of at least 10 w/w, still even more preferably of at least 15 w/w and still even more preferably of at least 20 w/w.
Preferably the cellulose fibers according to the invention are natural cellulose fibers (e.g. have not been subjected to chemical modification and more specifically is not carboxymethyl cellulose).
The oil absorbing capacity is measured according to the following method, which is based on 'the Standard Test Method for Oil Absorption of Pigments by Spatula Rub-out' (ASTM international, test number D281-12):
One gram of cellulose fiber is weighed and placed upon a glass plate. A bottle of with a known weight-amount of linseed oil is provided and used to add oil to the fiber, drop by drop. After the addition of each drop, the oil is thoroughly incorporated by rubbing up with a spatula. The addition of linseed oil is continued until a very stiff, putty-like paste, that does not break or separate is formed. The weight of added oil is determined (e.g. by weighing the amount of oil added from the bottle of linseed oil) and thereby amount of oil absorbed by the fiber w/w (e.g. gram of oil absorbed per gram of fiber) determined.
Cellulose fibers according to the invention are commercially available, for example under the trade name 'ARBOCEL Grade B 800', 'ARBOCEL Grade BE 600-20' (J. RETTENMAIER & SÖHNE GMBH, Holzmeuhle 1, Rosenberg, Germany); 'Oil Sponge AB' (PHASE III, 315 E Warner Rd, Chandler Arizona, USA); 'Bamboosilk' (Soliance, Place de la Madeleine 30, Paris, France); 'PowderSorb' (Applied Science & Advanced Technologies, Inc (ASAT, Inc), 10636 Linkwood CourtBaton Rouge, LA 70810,USA; and 'OILSPONGE Absorbents' (PHASEIII Chandler, AZ 85225 USA).

Water

The granular surface cleaning composition according to the invention comprises water which reduces dustiness and improves granule size stability. The composition according to the invention comprises from 10 to 45 wt. %, preferably from 20 to 40 wt. % and even more preferably from 25 to 35 wt. % of water. It will be appreciated that the water is typically completely comprised by the granules.

Optional ingredients

The granular surface cleaning composition according to the invention may comprise additional ingredients. Optionally added ingredients which are solid can be comprised by composite granules or form (single-component) granules themselves. In case optionally added ingredients are liquids it will be appreciated these will typically be part of (e.g. absorbed) composite granules and that the composition will preferably remain a free flowing powder and preferably without any visible liquid (e.g. water, oil).

Surfactants

The granular cleaning composition according to the invention comprises surfactant. Said surfactant (detergent active) is generally chosen from anionic and nonionic detergent actives. The cleaning composition may further or alternatively comprise cationic, amphoteric and zwitterionic surfactants.
Said granular cleaning composition comprises from 0.1 to 30 wt. %, more preferably from 0.5 to 15 wt. %, even more preferably from 1 to 10 wt. % and still even more preferably from 2 to 7 wt. % of surfactant.
An example of a suitable surfactant is conventional soap (i.e. salt of fatty acids, such as sodium stearate).
Suitable synthetic (non-soap) anionic surfactants are water-soluble salts of organic sulphuric acid mono-esters and sulphonic acids which have in the molecular structure a branched or straight chain alkyl group containing from 6 to 22 carbon atoms in the alkyl part.
Examples of such anionic surfactants are water soluble salts of:

(primary) long chain (e.g. 6-22 C-atoms) alcohol sulphates (hereinafter referred to as PAS), especially those obtained by sulphating the fatty alcohols produced by reducing the glycerides of tallow or coconut oil;
alkyl benzene sulphonates, such as those in which the alkyl group contains from 6 to 20 carbon atoms;
secondary alkanesulphonates;

Also suitable are the salts of:

alkylglyceryl ether sulphates, especially of the ethers of fatty alcohols derived from tallow and coconut oil;
fatty acid monoglyceride sulphates;
sulphates of ethoxylated aliphatic alcohols containing 1-12 ethyleneoxy groups;
alkylphenol ethylenoxy-ether sulphates with from 1 to 8 ethyleneoxy units per molecule and in which the alkyl groups contain from 4 to 14 carbon atoms;
the reaction product of fatty acids esterified with isethionic acid and neutralised with alkali;

The preferred water-soluble synthetic anionic surfactants are the alkali metal (such as sodium and potassium) and alkaline earth metal (such as calcium and magnesium) salts of alkyl-benzenesulphonates and mixtures with olefinsulphonates and alkyl sulphates, and the fatty acid mono-glyceride sulphates.
The most preferred anionic surfactants are alkyl-aromatic sulphonates such as alkylbenzenesulphonates 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 alkylbenzenesulphonates or of alkyl-toluene-, xylene- or phenolsulphonates, alkylnaphthalene-sulphonates, ammonium diamylnaphthalene-sulphonate, and sodium dinonyl-naphthalene-sulphonate.
If synthetic anionic surfactant is to be employed the amount present in the granular cleaning composition of the invention will generally be at least 0.1 wt. %, preferably at least 0.5 wt. %, more preferably at least 1.0 wt. %, but not more than 20 wt. %, preferably at most 10 wt. % and more preferably not more than 5 wt. %.
A suitable class of nonionic surfactants can be broadly described as compounds produced by the condensation of simple alkylene oxides, which are hydrophilic in nature, with an aliphatic or alkyl-aromatic hydrophobic compound having a reactive hydrogen atom. The length of the hydrophilic or polyoxyalkylene chain which is attached to any particular hydrophobic group can be readily adjusted to yield a compound having the desired balance between hydrophilic and hydrophobic elements. This enables the choice of nonionic surfactants with the right HLB. Particular examples include:

the condensation products of aliphatic alcohols having from 8 to 22 carbon atoms in either straight or branched chain configuration with ethylene oxide, such as a coconut alcohol/ethylene oxide condensates having from 2 to 15 mole of ethylene oxide per mole of coconut alcohol;
condensates of alkylphenols having C6-C15 alkyl groups with 5 to 25 mole of ethylene oxide per mole of alkylphenol;
condensates of the reaction product of ethylene-diamine and propylene oxide with ethylene oxide, the condensates containing from 40 to 80% of ethyleneoxy groups by weight and having a molecular weight of from 5,000 to 11,000.

Other classes of nonionic surfactants are:

tertiary amine oxides of structure R1R2R3N-O, where R1 is an alkyl group of 8 to 20 carbon atoms and R2 and R3 are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, e.g. dimethyldodecylamine oxide;
tertiary phosphine oxides of structure R1R2R3P-O, where R1 is an alkyl group of 8 to 20 carbon atoms and R2 and R3 are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, for instance dimethyl-dodecylphosphine oxide;
dialkyl sulphoxides of structure R1R2S=O, where R1 is an alkyl group of from 10 to 18 carbon atoms and R2 is methyl or ethyl, for instance methyl-tetradecyl sulphoxide;
fatty acid alkylolamides, such as the ethanol amides;
alkylene oxide condensates of fatty acid alkylolamides;
alkyl mercaptans.

If nonionic surfactant is to be employed the amount present in the granular cleaning composition of the invention will generally be at least 0.1 wt. %, preferably at least 0.5 wt. %, more preferably at least 1.0 wt. %, but not more than 20 wt. %, preferably at most 10 wt. % and more preferably not more than 5 wt. %.
It is also possible optionally to include amphoteric, cationic or zwitterionic surfactants in the granular cleaning composition according to the invention.
Suitable amphoteric surfactants are derivatives of aliphatic secondary and tertiary amines containing an alkyl group of 8 to 20 carbon atoms and an aliphatic group substituted by an anionic water-solubilising group, for instance sodium 3-dodecylamino-propionate, sodium 3-dodecylaminopropane-sulphonate and sodium N 2-hydroxy-dodecyl-N-methyltaurate.
Examples of suitable cationic surfactants can be found among quaternary ammonium salts having one or two alkyl or aralkyl groups of from 8 to 20 carbon atoms and two or three small aliphatic (e.g. methyl) groups, for instance cetyltrimethylammonium chloride.
A specific group of surfactants are the tertiary amines obtained by condensation of ethylene and/or propylene oxide with long chain aliphatic amines. The compounds behave like nonionic surfactants in alkaline medium and like cationic surfactants in acid medium.
Examples of suitable zwitterionic surfactants can be found among derivatives of aliphatic quaternary ammonium, sulphonium and phosphonium compounds having an aliphatic group of from 8 to 18 carbon atoms and an aliphatic group substituted by an anionic water-solubilising group, for instance betaine and betaine derivatives such as alkyl betaine, in particular C12-C16 alkyl betaine, 3-(N,N-dimethyl-N-hexadecylammonium)-propane 1-sulphonate betaine, 3-(dodecylmethyl-sulphonium)-propane 1-sulphonate betaine, 3-(cetylmethyl-phosphonium)-propane-1-sulphonate betaine and N,N-dimethyl-N-dodecyl-glycine. Other well known betaines are the alkylamidopropyl betaines e.g. those wherein the alkylamido group is derived from coconut oil fatty acids.
Further examples of suitable surfactants are compounds commonly used as surface-active agents given in the well-known textbooks: 'Surface Active Agents' Vol.1, by Schwartz & Perry, Interscience 1949; 'Surface Active Agents' Vol.2 by Schwartz, Perry & Berch, Interscience 1958; the current edition of 'McCutcheon's Emulsifiers and Detergents' published by Manufacturing Confectioners Company; 'Tenside-Taschenbuch', H. Stache, 2nd Edn., Carl Hauser Verlag, 1981.

Abrasives

The granular surface cleaning composition according to the invention comprises from 1 to 50 wt. %, more preferably from 2 to 40 wt. %, even more preferably from 3 to 30 wt. %, still even more preferably from 4 to 25 wt. % and still even more preferably from 5 to 15 wt. % of abrasive particles. However, it will be appreciated that the inclusion of abrasive particles in the composition according may depend on the intended use and in particular the sensitivity of the surface to scratching.
For example, a granular cleaning composition according to the invention which is intended for use as dry dish washing comprises abrasive particles.
The abrasive particles can be of any suitable material, both organic and inorganic. Examples of inorganic abrasive particles are abrasive particles made of zeolites, calcites, dolomites, feldspar, silicas, silicates, other carbonates, aluminas, bicarbonates, borates and sulphates.
Preferably the abrasive particles have sharp edges and an average a particle has at least one edge or surface having concave curvature. More preferably, the particles herein have a multitude of sharp edges and each particle has at least one edge or surface having concave curvature. The sharp edges of the particles are defined by edges having a tip radius below 20 pm, preferably below 8 pm, most preferably below 5 pm. The tip radius is defined by the diameter of an imaginary circle fitting the curvature of the edge extremity.
Preferably the average size of the abrasive particles is 1 to 200 µm, more preferably is 2 to 150 µm, even more preferably is at most is 3 to 100 µm and still even more preferably is 5 to 50 µm. It will be appreciated that abrasive particles may be comprised as single component and/or as composite granules and that the average granule size according to the invention (e.g. not below 0.05 milimeter) is adhered to.
Abrasive calcite particles in a range of different average particles sizes are commercially available. For example calcite particles with a mean particle size of 2.6, 5 or 35 µm are available for example under trade names Omyacarb 2 - AV, Omyacarb 5 - AV and Omyacarb 30 - AV respectively (Omya Greater South, Milano, Italy).
Examples of organic abrasive particles are abrasive particles made from nut shells (e.g. walnut shells) or olive stones.
Preferably the granular surface cleaning composition according to the invention comprises abrasive calcite particles.

Other optional ingredients

Optionally, the composition according to the invention may contain other ingredients, such as, colorants, whiteners, preservatives and aroma compounds. Preferably the granular cleaning composition according to the invention has a color which is different from ash, the color of ash typically being grey to black. This is believed to aid in visually assessing the degrees of mixing of the ash with the granular composition of the invention.

Ash

The granular composition according to any one of claims 1 to 12 can be mixed with ash before use as surface cleaning agent.
The ash as used herein is defined as the residue left after the burning of organic material, which preferably is plant material and more preferably is wood. It will be appreciated that the terms ash encompasses the material typically found in home-style wood stoves/ hearths after the burning of wood. Calcium carbonate is believed to be a principal component of the ash derived from of organic material, which typically further comprises potash, phosphate and other mineral elements.
The granular composition according to the invention has a cleaning efficiency, which is superior to that of only ash. It was observed that mixing up to 50 wt. % of wood ash with 50 wt. % of the granular composition had little or no negative effect on the cleaning efficiency (compared to the cleaning efficiency of the granular composition alone (i.e. unmixed with ash)). Also the cleaning efficiency of a mixture of 50 wt. % of ash with 50 wt. % of the granular composition according to any one of claims 1 to 12 was found to be far superior with that of only ash.
Therefore in another aspect the invention relates to a cleaning mixture comprising at least 25 wt. % of the granular composition according to any one of claims 1 to 12, and 0.5 to 75 wt. % of ash.
Preferably said cleaning mixture comprises at least 40 wt. %, more preferably at least 50 wt. %, even more preferably at least 60 wt. % and still even more preferably at least 75 wt. % of the granular composition according to any one of claims 1 to 12.
Preferably said cleaning mixture comprises 1 to 60 wt. %, more preferably 5 to 50 wt. %, even more preferably 10 to 40 wt. % and still even more preferably 15 to 25 wt. % of ash.
It will be appreciated that the cleaning mixture may comprises additional components but will mainly consist of ash and the granular composition. Preferably at least 50 wt. %, more preferably at least 75 wt. % and even more preferably at least 95 wt. % of the weight of the cleaning mixture is derived from the combined weight of the polyacrylic acid based swellable polymer, cellulose fiber, water and the ash.

Manufacture process

The composition according to the invention can be made by simply mixing the (liquid and solid components). Typically, the average granule size can be manipulated by the amount of liquid components added. It will be appreciated that the granule size can modified using techniques known it the art. For example pelleting can be used to increase granule size. For example, milling and grinding can be used to decrease granule size. For example sieving can be used to measure and/or select granules of a certain average size.
It will be appreciated that the composition according to the invention is granular and preferably will not contain any visible free liquid (e.g. water, oil).

Method of cleaning

The granular cleaning composition according to the invention can be used to clean surfaces by itself or optionally as mixed with ash without the use of added water. The granular nature allows easy mixing with the ash, which can be achieved by any suitable means, such as simply by hand.
It was found that in particular the composition according to the invention improved the cleaning capability of ash on hard surfaces. Therefore the granular composition (with or without ash) is particularly useful for to clean dishes and/or hard floors requiring little or no added water (e.g. waterless dish washing).
Cleaning may be carried out by simply applying the surface cleaning composition by itself, or mixed with ash, to the surface to be cleaned and leaving it stand for a sufficient period of time. It will be appreciated that to remove or reduce a specific stain/soil from a surface, the granular composition should be applied to said stain/soil
Preferably the applied composition is agitated on the surface. The agitation may be manual, such as by the act of rubbing and/or swiping. The agitation may also be carried out using suitable mechanical devices known in the art, such as a brush.
Finally, the applied composition and the optionally applied ash can be removed from the surface, preferably without the aid of added water. The waterless removal may be done by any suitable means such as by use of a brush, a vacuum cleaner, air movement or in some cases even gravity. It will be appreciated that depending on the type of stain/soil, some means will be more suitable than other to remove the applied material. For example, liquid stains/soils will readily be absorbed and possible coagulate the granules into a paste. In such a case, brushing is more suitable for removal than the use of air movement.
Therefore in another aspect the invention relates to a surface cleaning method comprising the steps of:

a) applying the granular composition of the invention according to any one of claims 1 to 12; and optionally ash to a surface;
b) optionally agitating the granules on the surface;
c) removing the material applied at step 'a', preferably without using added water, such as by brushing.

Preferably the removing of the applied material at step 'c' is performed by brushing.
Although not preferred, it will be appreciated that removal of the applied material at step 'c' with the aid of water is encompassed by the cleaning method of the present invention.
Preferably the method according to the invention to clean a surface is used to manually wash dishes with little or no use of added water. With dish surfaces is meant herein dishes, glasses, pots, pans, baking dishes and flatware made from ceramic, china, metal, glass, plastic (polyethylene, polypropylene,polystyrene, etc.), wood, enamel, Inox, Teflon, or any other material commonly used in the making of articles used for eating and/or cooking.
Alternatively and preferably the method according to the invention is used to clean floor surfaces (e.g. tiles or carpet), more preferably hard floor surfaces with little or no added water.
The invention will now be further described with reference to the following non-limiting examples.

Examples

Assessment of cleaning efficiency

The cleaning efficiency was assessed by measuring stain removal from a white ceramic tile using a gravimetric assay according to the following steps:

1. Firstly white ceramic tiles were numbered and weighed.
2. Secondly 1 gram of staining material was applied to each tile.
3. Thirdly 1 gram of a cleaning composition was applied to the tile and allowed to incubate form 1 minute.
4. Finally the tile surface was brushed and the tiles again weighed.

The stain removal (i.e. cleaning efficiency) was determined by subtracting the final weight measured at step '4' from the initial weight of the tile measured at step '1'. A lower increase in weight is indicative of an improved cleaning efficiency. The cleaning efficiency was quantified as the amount of wt. % of stain, which was removed from the tile, based on the initial stain weight of 1gram. Experiments were carried out in triplicate.

The composition of Example 1 and Comparative A were prepared according to the formulation as indicated in table 1.

Table 1. Formulation of Example 1 and Comparative A.

	Wt. %
Ingredients	Example 1	Example 2	Comparative A
Cellulose fibers B800¹	60	30	-
Perfume	0.1	0.05	-
Partially cross-linked polyacrylic acid²	3	1.5	-
CocoAmine Oxide	2	1.0	-
Burnt wood ash³	-	50	100
Water	to balance	to balance

1.Tradename: ARBOCEL Grade B 800, Supplier: J. RETTENMAIER & SÖHNE GMBH
2. Tradename: Polyhipe, Supplier: Rohm and Haas Company.
3. The burnt wood ash was obtained from a home hearth which was used to burn wood.

The components of Example 1 were mixed and a granular composition with an average granule size of about 0.3 mm was obtained.
Example 2 was made by mixing 50 wt. % of burnt wood ash with 50 wt. % of the granular composition of Example 1.

Results

The cleaning efficiency of Example 1, Example 2 and Comparative 1were assessed using the gravimetric assay as described (Table 2).
The staining material was either stain-type 'a' (liquid vegetable oil comprising 0.002 wt. % of Sudan Red as coloring) or stain-type 'b' (a 1:1weight mixture of liquid vegetable oil and water further comprising 0.002 wt. % Sudan Red). Table 2. Cleaning efficiency

wt.% of stain removed

Stain-type a Stain-type b

Example 1 72 81

Example 2 67 81

Comparative A 27 28

Claims

A granular surface cleaning composition comprising:
• from 0.2 to 12 wt. % of polyacrylic acid based swellable polymer;

• from 10 to 80 wt. % of cellulose fiber;

• from 10 to 45 wt. % of water;

• 0.1 to 30 wt. % of surfactant;

• 1 to 50 wt. % of abrasive particles;
wherein the average granule size is from 0.05 to 5 millimeter.
A composition according to claim 1, wherein the average granular size is 0.06 to 3, more preferably from 0.07 to 2 and even more preferably from 0.1 to 1 millimeter.
A composition according to claim 1 or claim 2, wherein at the average molecular weight of the polymer is from 10,000 to 50,000,000 Daltons, preferably from 1,000,000 to 25, 000, 000 Daltons and more preferably from 5,000,000 to 20,000,000 Daltons.
A composition according to any one of claims 1 to 3, wherein the polymer is partially cross-linked and more preferably comprises 0.1 to 2 wt. %, even more preferably 0.2 to 1 wt. % and still even more preferably 0.3 to 0.8 wt. % of cross-linker, based on the total weight of the final polymer.
A composition according to any one of claims 1 to 4, wherein at least 70 wt. %, preferably at least 80 wt. %, more preferably 90 wt. % and even more preferably at least 95 wt. % of the weight of the polymer is derived from acrylic acid monomers.
A composition according to any one of claims 1 to 5, wherein amount of polymer is from 0.5 to 8 wt. %, preferably from 1 to 5 wt. %.
A composition according to any one of claims 1 to 6, wherein amount of cellulose fiber is from 20 to 75 wt. %, preferably from 30 to 70 wt. % and more preferably from 40 to 65 wt. %.
A composition according to any one of claims 1 to 7, wherein the cellulose fibers have an oil absorbing capacity of at least 5 w/w, more preferably of at least 7 w/w, even more preferably of at least 10 w/w, still even more preferably of at least 15 w/w and still even more preferably of at least 20 w/w.
A composition according to anyone of claims 1 to 8, wherein the amount of water is from 20 to 40 wt. % and preferably from 25 to 35 wt. %.
A composition according to any one of claims 1 to 9, comprising from 0.5 to 15 wt. %, more preferably from 1 to 10 wt. % and even more preferably from 2 to 7 wt. % of surfactant.
A composition according to any one of claims 1 to 10, comprising from 1 to 50 wt. %, preferably from 2 to 40 wt. %, more preferably from 3 to 30 wt. %, even more preferably from 4 to 25 wt. % and still even more preferably from 5 to 15 wt. % of abrasive calcite particles.
A cleaning mixture comprising at least 25 wt. %, of the granular composition according to any one of claims 1 to 11; and 0.5 to 75 wt. % of ash.
A method for the cleaning of a surface comprising the steps of:
a) applying the granular composition according to any one of claims 1 to 11; and optionally ash to a surface;

b) optionally agitating the granules on the surface;

c) removing the material applied at step 'a', preferably without using added water, such as by brushing.
A method according to claim 13, wherein the surface is a dish or floor surface and preferably a hard floor surface.