Compositions and method of use relating thereto

Abstract

A toilet cleaning composition comprising a surfactant, a non-phosphoric chelating agent and acrylic acid polymer. A toilet cleaning composition comprising a surfactant, a non-phosphoric chelating agen

Description

The present invention relates to household and industrial cleaning compositions, especially cleaning compositions which also reduce limescale formation. In hard water areas the formation of limescale can be problematic in a number of applications, for example in automatic dishwashers, laundry washing machines and toilets. The present invention relates in particular to toilet cleaning compositions, for example toilet blocks. Toilet blocks include rim blocks that are placed at the rim of a toilet bowl and cistern blocks that are placed within a toilet cistern. Toilet blocks dispense active cleaning ingredients in the toilet bowl each time the toilet is flushed. They typically last for multiple flushes and are thus a convenient tool for keeping a toilet clean and malodour-free for extended periods of time without having to repeatedly apply a cleaning composition to the toilet. As well as keeping toilets clean, toilet blocks also help to prevent limescale forming within the toilet bowl. The surfactants used in toilet blocks typically form insoluble salts upon contact with magnesium or calcium ions present in hard water and these insoluble salts can form residues on the toilet bowl. It is therefore common to include sodium tripolyphosphate in toilet block products. Sodium tripolyphosphate is very effective at preventing the formation of limescale and residues in the toilet bowl. There is a desire to reduce the inclusion of phosphorus containing compounds in cleaning compositions for environmental reasons. However compositions in which the phosphate based chelating agents have been simply replaced with phosphorus free alternatives have been found to exhibit poor limescale prevention and reduction. Certain surfactants used in laundry and automatic dishwashing applications also form insoluble residues, particularly when used in hard water areas. These residues may remain on laundry or dishes at the end of the cycle causing consumer dissatisfaction. Elimination of phosphorus compounds in these applications is also highly desirable for environmental reasons. The present inventors have surprisingly found that certain compositions comprising acrylic acid derived polymers can provide excellent limescale prevention performance even in the absence of phosphate containing chelating agents. According to a first aspect of the present invention there is provided a cleaning composition comprising: (a) at least one surfactant compound; (b) at least one phosphorus free chelating agent; and (c) at least one acrylic acid derived polymer. The cleaning composition of the first aspect may be provided as a solid, paste, gel or liquid. Preferably it is provided as a solid. The cleaning composition of the present invention comprises (a) at least one surfactant compound. Suitable surfactant compounds include anionic surfactants, non ionic surfactants, amphoteric surfactants and cationic surfactants. Biosurfactants falling within these classes may also be useful. Component (a) may comprise a mixture of two or more surfactant compounds. Suitable anionic surfactants for use herein include salts of: fatty acids; alkoxylated carboxylic acids; ester carboxylates; ethoxylated ester carboxylates; mono- or dialkyl sulfates; mono- or dialkyl ether sulfates; lauryl ether sulfates; alkyl sulfonates; alkyl aryl sulfonates; primary alkane disulfonates; alkene sulfonates; hydroxyalkane sulfonates; isethionates, alkyl isethionates, acyl isethionates, acyl alkyl isethionates, alkyl glyceryl ether sulfonates; alphaolefin sulfonates; sulfonates of alkylphenolpolyglycol ethers; alkyl sulfopolycarboxylic acid esters; alkyl sulfosuccinates; alkyl ether sulfosuccinates; taurates; acyl taurates; acyl N-alkyl taurates; products of condensation of fatty acids with oxy- and aminoalkanesulfonic acids; sulfated derivatives of fatty acids and polyglycols; alkyl and acyl sarcosinates; sulfoacetates; acyl lactates; alkanolamides of sulfated fatty acids, lipoamino acids and acyl substituted amino acids, for example acyl glycinates and acyl glutamates. Particularly exemplary salts, where applicable, are the sodium, potassium, ammonium, magnesium and triethanolamine salts. Polymeric anionic surfactants may also be used. Suitable anionic surfactants for use in the present invention typically comprise one or more moieties selected from sulfate, sulfonate, carboxylate and mixtures thereof. Suitable non-ionic surfactants for use in compositions of the first aspect of the invention include alcohol alkoxylates such as alcohol ethoxylates, alcohol propoxylates, and ethylene oxide / propylene oxide copolymer derived surfactants, aliphatic esters, aromatic esters, sugar esters, especially sorbitan esters, alkyl glucosides, fatty acid alkoxylates such as fatty acid ethoxylates and fatty acid propoxylates or polyethylene glycol esters and partial esters, glycerol esters including glycerol partial esters and glycerol triesters, fatty alcohols (such as cetearyl alcohol, lauryl alcohol, stearyl alcohol, behenyl alcohol), alkanolamides and amineoxides. Polymeric non-ionic surfactants may also be used. Suitable non-ionic surfactants may be selected from the following: reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide (for example alkyl (C6-C22) phenol-ethylene oxide condensates, the condensation products of aliphatic (Ca-C-ia) primary or secondary linear or branched alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine); long chain tertiary amine oxides, and dialkyl sulfoxides; alkyl amine oxides, alkyl amido amine oxides; alkoxyl alkyl amines; sorbitan; sorbitan esters; sorbitan ester alkoxylates; glycerol ester alkoxylates; sucrose esters; sugar amides, such as a saccharide amide; lactobionamides; and alkyl saccharide nonionic surfactants, for example alkyl glycosides. Preferred non-ionic surfactants are alcohol ethoxylates, alkanolamides and alkyl polyglucosides. Suitable amphoteric surfactants for use in compositions of the first aspect of the invention include those based on fatty nitrogen derivatives and those based on betaines. Suitable amphoteric or zwitterionic surfactants may be selected from betaines, for example alkyl betaines, alkylamidopropyl betaines, for example cocamidopropyl betaine, alkylamidopropyl sultaines alkylamidopropyl hydroxy sultaines, alkylamphoacetates, alkylamphodiacetates, alkyl propionates, alkylamphodipropionates, alkylamphopropionates, alkyliminodipropionates and alkyliminodiacetate. Polymeric amphoteric surfactants may also be used. Suitable cationic surfactants for use in compositions of the first aspect of the invention are typically based on fatty amine derivates and quaternary ammonium compounds. Polymeric cationic surfactants may also be used. Suitable cationic surfactants for use in compositions of the first aspect of the invention include tertiary amine salts, mono alkyl trimethyl ammonium chloride, mono alkyl trimethyl ammonium methyl sulfate, dialkyl dimethyl ammonium chloride, dialkyl dimethyl ammonium methyl sulfate, trialkyl methyl ammonium chloride, benzalkonium chloride, cetyl trimethyl ammonium chloride and trialkyl methyl ammonium methyl sulfate. Suitable biosurfactants include rhamnolipids, trehalolipids, sophorolipids, mannosylerythritol lipids, and glycolipids produced by Meyerozama guilliermondii, Saccharomyces cerevisiae, Candida utilis, Candida bombicola and / or Marinobacter hydrocarbonoclasticus. Preferably component (a) comprises one or more anionic surfactants. Preferred anionic surfactants include sodium alkyl benzene sulfonates, sodium alkyl sulfates, sodium alkyl ether sulfates, methyl ester sulfonates, acyl glutamates, fatty acid isethionates, fatty acid alkyl isethionates, acylamino alkanesulfonates (fatty acid taurides) and fatty acid salts (soaps). In especially preferred embodiments component (a) comprises an alkyl benzene sulfonate surfactant, especially a sodium alkyl benzene sulfonate surfactant. More preferably component (a) comprises an alkyl benzene sulfonate surfactant having an alkyl group of from 4 to 36 carbon atoms, preferably 6 to 30 carbon atoms, more preferably 6 to 24 carbon atoms, preferably 8 to 20 carbon atoms, suitably 8 to 16 carbon atoms, preferably 10 to 14 carbon atoms. Most preferably component (a) comprises sodium dodecyl benzene sulfonate. In some embodiments component (a) comprises an alkyl sulfate surfactant or an alkyl ether sulfate surfactant. Sodium salts are preferred. Preferred alkyl ether sulfate surfactants are sulfated alcohol ethoxylate salts, for example sodium laureth-2 sulfate. In some embodiments component (a) comprises an alkyl ether sulfate surfactant and an alkyl benzene sulfonate surfactant. In some embodiments component (a) comprises an alkyl sulfate surfactant and an alkyl benzene sulfonate surfactant. The cleaning composition of the first aspect of the present invention further comprises (b) at least one phosphorus free chelating agent. Suitable phosphorus free chelating agents will be known to the person skilled in the art. Preferred chelating agents for use in the present invention are polycarboxylic acids. By this we mean that the chelating agent includes two or more carboxylic acid moieties or salts thereof. Suitable chelating agents may include 3, 4 or 5 carboxylic acid moieties. Suitable phosphorus free chelating agents include hydroxyethyliminodiacetic acid (HEIDA), glucoheptonic acid, hydroxyethylenediaminetetraacetic acid (HEDTA), hydroxyethylethylenediaminetriacetic acid (HEEDTA), ethylenediamine disuccinic acid (EDDS), methylglycinediacetic acid (MGDA), glutamic acid, N,N-diacetic acid (GLDA), iminodisuccinic acid (IDS); ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA), aspartic acid diethoxysuccinic acid (AES), ethylenediaminediglutaric acid, 2-hydroxypropylenediamine disuccinic acid, N- ethylenediamine tetrapropionic acid, triethylenetetraaminehexa-acetic acid, ethanol-diglycines, propylene diamine tetracectic acid (PDTA), aspartic acid-N,N-diacetic acid (ASDA), iminodifumaric (IDF), iminoditartaric acid (IDT), iminodimaleic acid (IDMAL), iminodimalic acid (IDM), ethylenediaminedifumaric acid (EDDF), ethylenediaminedimalic acid (EDDM), ethylenediamineditartaric acid (EDDT), ethylenediaminedimaleic acid (EDDMAL), citric acid and salts and mixtures thereof. Preferably component (b) comprises one or more phosphorus free chelating agents selected from methylglycinediacetic acid (MGDA), citric acid and mixtures and / or salts thereof. Methylglycinediacetic acid (MGDA) is preferably provided as a trisodium salt. Citric acid is preferably provided as a trisodium salt. In some preferred embodiments component (b) comprises an aminopolycarboxylate chelating agent. Preferred aminopolycarboxylate chelating agents include methylglycinediacetic acid (MGDA), ethylenediaminetetraacetic acid (EDTA), ethylenediamine disuccinic acid (EDDS) and salts and / or mixtures thereof. The cleaning composition of the first aspect of the present invention further comprises (c) at least one acrylic acid derived polymer. By acrylic acid derived polymer we mean to include any polymer which is prepared from an acrylic acid monomer or an acrylic acid based monomer. Acrylic acid based monomers include methacrylic acid, salts of acrylic acid, esters of acrylic acid, amides of acrylic acid, salts of methacrylic acid, esters of methacrylic acid, amides of methacrylic acid, and mixtures thereof. Preferred salts are sodium salts. In some embodiments the acrylic acid derived polymer is a homopolymer. In some embodiments the acrylic derived polymer is a copolymer. Copolymers are suitably prepared from an acrylic acid based monomer and one or more further different monomers. In some embodiments component (c) comprises a homopolymer of acrylic acid. The homopolymer of acrylic acid may be partially neutralised. Partially neutralised acrylic acid homopolymers are those in which a proportion of the carboxylic acid residues present in the polymer have been neutralised to form a salt, typically a sodium salt and the remaining acid groups are present as the free acid. In some embodiments the acrylic acid homopolymer may be fully neutralised. In such embodiments substantially all of the carboxylic residues are in the form of a salt. Suitable salts include sodium, potassium, ammonium and alkanolammonium (e.g. triethanolammonium) salts. Preferred salts are sodium salts. In some embodiments substantially all of the carboxylic acid groups of the acrylic acid homopolymer are present as the free acid. From 0 to 100 mol% of the carboxylic acid groups of the acrylic acid homopolymer are neutralised. In some embodiments from 10 to 90 mol% may be neutralised. In some embodiments 70 to 100 mol% may be neutralised. In some embodiments from 30 to 70 mol% may be neutralised. In some embodiments 1 to 40 mol% may be neutralised. Preferred homopolymers suitably have a weight average molecular weight of from 500 to 30000, preferably from 2000 to 20000, suitably from 2000 to 10000. Weight average molecular weight may be measured by means known to the person skilled in the art, for example by size exclusion chromatography. In some embodiments component (c) may comprise a copolymer of an acrylic acid based monomer and one or more further monomers. Suitable further monomers include an alkene functional group. Examples of suitable further monomers include further different acrylic acid based monomers, alkenes, conjugated dienes, styrenes and halo-styrenes (e.g. a-methylstyrene), divinylbenzene, acrolein, vinyl acetate, vinylpyrrolidone, vinylimidazole and maleic anhydride. Preferred further monomers also include an acid moiety, for example a carboxylic acid or sulfonic acid group. Preferred further monomers are sulfonated monomers. In some embodiments component (c) comprises a copolymer of acrylic acid and a sulfonated monomer. The sulfonated monomer is preferably selected from 2-acrylamido-2-methylpropane sulfonic acid (AMPS), 2-methacrylamido-2-methylpropane sulfonic acid, 4-styrenesulfonic acid, vinylsulfonic acid, 3-allyloxy sulfonic acid, 2-hydroxy-1-propane sulfonic acid (HAPS), 2-sulfoethyl(meth)acrylic acid, 2-sulfopropyl(meth)acrylic acid, 3-sulfopropyl(meth)acrylic acid, 4-sulfobutyl(meth)acrylic acid and salts and mixtures thereof. Especially preferred is a copolymer of acrylic acid and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and salts thereof. Preferred sulfonated copolymers comprise from 50 to 95 wt% (preferably, 60 to 94 wt%; more preferably, 65 to 93 wt%; most preferably, 68 to 90 wt%), based on weight of the sulfonated copolymer, of structural units of acrylic acid; and 5 to 50 wt% (preferably, 6 to 40 wt%; more preferably, 7 to 35 wt%; most preferably, 10 to 32 wt%), based on weight of the sulfonated copolymer, of structural units of sulfonated monomer. Preferably the sulfonated copolymer has a weight average molecular weight of from 1000 to 50000, preferably from 5000 to 40000, suitably from 10000 to 30000, for example from 12000 to 25000 or from 14000 to 18000. In some embodiments component (c) may comprise a mixture of two or more acrylic acid derived polymers. In some embodiments component (c) comprises an acrylic acid homopolymer and a copolymer of acrylic acid and one or more further monomers. In some preferred embodiments component (c) comprises an acrylic acid homopolymer and a copolymer of acrylic acid and a sulfonated monomer. In such embodiments the weight ratio of the acrylic acid homopolymer to the copolymer of acrylic acid and a sulfonated monomer is suitably from 50:1 to 1:50, preferably from 10:1 to 1:10, more preferably from 5:1 to 1:5, for example from 2:1 to 1:2. In some preferred embodiments component (c) comprises an acrylic acid homopolymer and a copolymer of acrylic acid and a sulfonated monomer selected from 2-acrylamido-2-methylpropane sulfonic acid (AMPS), 2-methacrylamido-2-methylpropane sulfonic acid, 4-styrenesulfonic acid, vinylsulfonic acid, 3-allyloxy sulfonic acid, 2-hydroxy-1-propane sulfonic acid (HAPS), 2-sulfoethyl(meth)acrylic acid, 2-sulfopropyl(meth)acrylic acid, 3-sulfopropyl(meth)acrylic acid, 4-sulfobutyl(meth)acrylic acid and salts and mixtures thereof. In some preferred embodiments component (c) comprises an acrylic acid homopolymer and a copolymer of acrylic acid and 2-acrylamido-2-methylpropane sulfonic acid (AMPS). In some preferred embodiments component (c) comprises an acrylic acid homopolymer which is partially or fully neutralised and a copolymer of acrylic acid and 2-acrylamido-2-methylpropane sulfonic acid (AMPS). In some preferred embodiments component (c) comprises an acrylic acid homopolymer which is partially or fully neutralised and has a weight average molecular weight of from 1000 to 10000, preferably 2000 to 6000; and a copolymer of acrylic acid and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) having a weight average molecular weight of from 5000 to 40000, preferably 12000 to 25000. Component (a) preferably provides at least 1 wt% of the cleaning composition, preferably at least 5 wt%, suitably at least 10 wt%. Component (a) may provide up to 70 wt% of the cleaning composition, for example up to 40 wt%. Suitably the cleaning composition comprises from 1 to 60 wt%, preferably from 5 to 90 wt%, more preferably from 10 to 60 wt%, preferably from 20 to 40 wt%, for example from 25 to 35 wt% component (a). Component (a) may comprise a mixture of surfactant compounds. In embodiments in which two or more surfactant compounds are present the above amounts refer to the total amount of all surfactant compounds present in the cleaning composition. The amounts represent the amount of active surfactant compounds present in the composition, ignoring any byproduct, residual starting material or diluent that may be present. Component (b) preferably provides at least 0.1 wt% of the cleaning composition, preferably at least 0.25 wt%, suitably at least 0.5 wt%. Component (b) may provide up to 20 wt% of the cleaning composition, for example up to 5 wt%. Suitably the cleaning composition comprises from 0.01 to 30 wt%, preferably from 0.05 to 20 wt%, more preferably from 0.1 to 10 wt%, preferably from 0.25 to 6 wt%, for example from 0.5 to 5 wt% component (b). Component (b) may comprise a mixture of phosphorus free chelating agents. In embodiments in which two or more phosphorus free chelating agents are present the above amounts refer to the total amount of all phosphorus free chelating agents present in the cleaning composition. Component (c) preferably provides at least 0.1 wt% of the cleaning composition, preferably at least 0.25 wt%, suitably at least 0.5 wt%. Component (c) may provide up to 20 wt% of the cleaning composition, for example up to 5 wt%. Suitably the cleaning composition comprises from 0.01 to 30 wt%, preferably from 0.05 to 20 wt%, more preferably from 0.1 to 10 wt%, preferably from 0.25 to 6 wt%, for example from 0.5 to 4 wt% component (c). Component (c) may comprise a mixture of acrylic acid derived polymers. In embodiments in which two or more acrylic acid derived polymers are present the above amounts refer to the total amount of all acrylic acid derived polymers present in the cleaning composition. The cleaning composition of the first aspect of the present invention may optionally comprise one or more further ingredients. Suitable further ingredients will depend on the intended use of the composition. The selection of suitable further components will be within the competence of the person skilled in the art. In preferred embodiments, especially embodiments in which the cleaning composition is a toilet cleaning composition, the cleaning composition further comprises (d) a filler. Suitable fillers will be known to the person skilled in the art. In some embodiments the filler is an inorganic salt selected from sulfates, carbonates, halides, zeolites, silicates and combinations thereof. In some embodiments the inorganic salt is selected from sulphates, carbonates and combinations thereof. In some preferred embodiments component (d) does not comprise carbonate or silicate fillers. In some embodiments the cleaning composition of the first aspect of the present invention comprises less than 10 wt% carbonate salts, preferably less than 3 wt%, more preferably less than 1 wt%. In some embodiments the cleaning composition of the present invention comprises less than 10 wt% silicate salts, preferably less than 3 wt%, more preferably less than 1 wt%. The inorganic salt that may be employed as a filler is preferably selected from alkali metal salts, earth alkaline metal salts, ammonium salts and combinations thereof. Preferred are alkali metal salts, especially sodium salts. Preferred fillers for use herein are sodium salts. Especially preferred fillers for use herein are sulfates, chlorides and citrates. Most preferably component (d) is selected from sodium sulfate, sodium chloride, sodium citrate and mixtures thereof. A preferred filler is sodium sulfate. Component (d) preferably provides at least 5 wt% of the cleaning composition, preferably at least 10 wt%, suitably at least 20 wt%. Component (d) may provide up to 90 wt% of the cleaning composition, for example up to 75 wt%. Preferably component (d) provides at least 45 wt% of the cleaning composition, for example at least 50 wt%. Suitably the cleaning composition comprises from 1 to 95 wt%, preferably from 5 to 90 wt%, more preferably from 10 to 85 wt%, preferably from 40 to 80 wt%, for example from 50 to 75 wt% component (d). Component (d) may comprise a mixture of fillers. In embodiments in which two or more fillers are present the above amounts refer to the total amount of all fillers present in the cleaning composition. The cleaning composition of the first aspect of the present invention preferably comprises less than 10 wt% water, preferably less than 6 wt%, suitably less than 4 wt%, preferably less than 3 wt%. The cleaning composition of the first aspect of the present invention may comprise one or more further components. In preferred embodiments the cleaning composition comprises a colorant. Suitable colorants are known to the person skilled in the art. In preferred embodiments the cleaning composition of the present invention does not comprise substantial amounts of thickening agents. Preferably the cleaning composition of the present invention comprises less than 10 wt% thickening agents, preferably less than 5 wt%, suitably less than 3 wt%, for example less than 1 wt%. Preferably the cleaning composition of the present invention comprises less than 10 wt% of polymeric thickening agents, preferably less than 5 wt%, suitably less than 3 wt%, for example less than 1 wt%. Preferably the cleaning composition of the first aspect of the present invention comprises less than 10 wt% carrageenan, preferably less than 5 wt%, more preferably less than 3 wt%, most preferably less than 1 wt%. In some preferred embodiments the cleaning composition of the present invention comprises less than 0.5 wt% or less than 0.1 wt% of carrageenan. In some embodiments the cleaning composition is an automatic dishwashing or a laundry detergent composition. It may be a solid composition, a liquid composition, or a gel or paste. It may be in the form of a free flowing powder, a tablet, a liquid, a pouch or multicomponent product. The cleaning composition of the present invention may provide one component in of a multicomponent pouch or tablet. Laundry and automatic dishwashing compositions suitably comprise builders and a mixture of surfactants. Preferred builders are silicates and zeolites. Suitable surfactants for use in automatic dishwashing and laundry compositions will be known to the person skilled in the art and include those described in relation to component (a). For automatic dishwashing compositions low foaming surfactants, such as ethoxylated non-ionic surfactants are preferred. The laundry compositions may also comprise one or more further ingredients selected from bleaching agents, bleach activators, pigments, dyes, fragrances, enzymes, biocides, preservatives and pH adjusting agents. The automatic dishwashing compositions may comprise further ingredients selected from surfactants, builders, bleaches, bleach activators, redeposition additives, dye transfer inhibitors, enzymes, colorants and fragrances. In preferred embodiments the cleaning composition of the first aspect of the present invention is a toilet cleaning composition. The toilet cleaning composition may further comprise one or more further ingredients selected from builders, perfume, bleaching agents, polymers, corrosion inhibitors, flush regulators, adhesion inhibitors, pH regulators, enzymes, preservatives, probiotics, organic acids, hydrotropes, solvents, biocides and rheology modifiers. Suitable such components will be known to the person skilled in the art. The toilet cleaning composition preferably comprises a filler, most preferably sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) an alkyl benzene sulfonate surfactant; (b) a phosphorus free chelating agent; (c) an acrylic acid homopolymer; and (d) sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) an alkyl benzene sulfonate surfactant; (b) a phosphorus free chelating agent; (c) a copolymer of acrylic acid and a sulfonated monomer (preferably AMPS); and (d) sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) an alkyl benzene sulfonate surfactant; (b) a phosphorus free chelating agent; (c) an acrylic acid homopolymer and a copolymer of acrylic acid and a sulfonated monomer (preferably AMPS); and (d) sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) an alkyl benzene sulfonate surfactant; (b) methylglycinediacetic acid (MGDA) and / or citric acid or salts thereof; (c) an acrylic acid homopolymer; and (d) sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) an alkyl benzene sulfonate surfactant; (b) methylglycinediacetic acid (MGDA) and / or citric acid or salts thereof; (c) a copolymer of acrylic acid and a sulfonated monomer (preferably AMPS); and (d) sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) an alkyl benzene sulfonate surfactant; (b) methylglycinediacetic acid (MGDA) and / or citric acid or salts thereof; (c) an acrylic acid homopolymer and a copolymer of acrylic acid and a sulfonated monomer (preferably AMPS); and (d) sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) 10 to 45 wt%, preferably 25 to 35 wt% of an alkyl benzene sulfonate surfactant; (b) 0.1 to 10 wt%, preferably 0.5 to 5 wt% of methylglycinediacetic acid (MGDA) and / or citric acid or salts thereof; (c) 0.1 to 10 wt%, preferably 0.5 to 4 wt% of an acrylic acid homopolymer; and (d) 50 to 90 wt%, preferably 60 to 80 wt% of sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) 10 to 45 wt%, preferably 25 to 35 wt% of an alkyl benzene sulfonate surfactant; (b) 0.1 to 10 wt%, preferably 0.5 to 5 wt% of methylglycinediacetic acid (MGDA) and / or citric acid or salts thereof; (c) 0.1 to 10 wt%, preferably 0.5 to 4 wt% of a copolymer of acrylic acid and a sulfonated monomer (preferably AMPS); and (d) 50 to 90 wt%, preferably 60 to 80 wt% of sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) 10 to 45 wt%, preferably 25 to 35 wt% of an alkyl benzene sulfonate surfactant; (b) 0.1 to 10 wt%, preferably 0.5 to 5 wt% of methylglycinediacetic acid (MGDA) and / or citric acid or salts thereof; (c) 0.1 to 10 wt%, preferably 0.5 to 4 wt% of an acrylic acid homopolymer and a copolymer of acrylic acid and a sulfonated monomer (preferably AMPS); and (d) 50 to 90 wt%, preferably 60 to 80 wt% of sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) an alkyl benzene sulfonate surfactant; (b) an aminopolycarboxylate chelating agent, preferably methylglycinediacetic acid (MGDA); (c) an acrylic acid homopolymer; and (d) sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) an alkyl benzene sulfonate surfactant; (b) an aminopolycarboxylate chelating agent, preferably methylglycinediacetic acid (MGDA); (c) a copolymer of acrylic acid and a sulfonated monomer (preferably AMPS); and (d) sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) an alkyl benzene sulfonate surfactant; (b) an aminopolycarboxylate chelating agent, preferably methylglycinediacetic acid (MGDA); (c) an acrylic acid homopolymer and a copolymer of acrylic acid and a sulfonated monomer (preferably AMPS); and (d) sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) 10 to 45 wt%, preferably 25 to 35 wt% of an alkyl benzene sulfonate surfactant; (b) 0.1 to 10 wt%, preferably 0.5 to 5 wt% of an aminopolycarboxylate chelating agent, preferably methylglycinediacetic acid (MGDA); (c) 0.1 to 10 wt%, preferably 0.5 to 4 wt% of an acrylic acid homopolymer; and (d) 50 to 90 wt%, preferably 60 to 80 wt% of sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) 10 to 45 wt%, preferably 25 to 35 wt% of an alkyl benzene sulfonate surfactant; (b) 0.1 to 10 wt%, preferably 0.5 to 5 wt% of an aminopolycarboxylate chelating agent, preferably methylglycinediacetic acid (MGDA); (c) 0.1 to 10 wt%, preferably 0.5 to 4 wt% of a copolymer of acrylic acid and a sulfonated monomer (preferably AMPS); and (d) 50 to 90 wt%, preferably 60 to 80 wt% of sodium sulfate. In one embodiment the toilet cleaning composition comprises: (a) 10 to 45 wt%, preferably 25 to 35 wt% of an alkyl benzene sulfonate surfactant; (b) 0.1 to 10 wt%, preferably 0.5 to 5 wt% of an aminopolycarboxylate chelating agent, preferably methylglycinediacetic acid (MGDA); (c) 0.1 to 10 wt%, preferably 0.5 to 4 wt% of an acrylic acid homopolymer and a copolymer of acrylic acid and a sulfonated monomer (preferably AMPS); and (d) 50 to 90 wt%, preferably 60 to 80 wt% of sodium sulfate. A particular advantage of the compositions of the present invention is that they maintain limescale reduction and cleaning performance despite not containing phosphate compounds. This offers significant environmental benefits. Preferably the cleaning composition of the first aspect of the present invention comprises less than 1 wt% phosphate ions, preferably less than 0.1 wt%, more preferably less than 0.01 wt%. Preferably the cleaning composition of the first aspect of the present invention is substantially free of phosphate ions. Preferably the cleaning composition of the first aspect of the present invention comprises less than 1 wt% phosphorus containing compounds, preferably less than 0.1 wt%, more preferably less than 0.01 wt%. Preferably the cleaning composition of the first aspect of the present invention is substantially free of phosphorus containing compounds. The cleaning composition of the first aspect of the present invention may be provided in any suitable form. Preferably the cleaning composition is provided as a solid. In some embodiments the cleaning composition may be provided as a free flowing powder. In some preferred embodiments the cleaning composition is provided in the form of a solid block. The solid block may be formed from a melt by moulding or extrusion. Advantageously the cleaning composition of the present invention may be provided as a solid extruded block. In some preferred embodiments the solid block comprises a pressed powder, In some preferred embodiments the cleaning composition is a toilet cleaning composition in the form of a solid block. Preferably the toilet cleaning composition of the first aspect of the present invention has an acceptable lifespan. The lifespan of compositions may be tested by flushing at random intervals a toilet to which a cage has been attached at the rim containing one or more blocks of the cleaning composition. Advantageously the cleaning compositions of the present invention have a lifespan of greater than 250 flushes, preferably greater than 300 flushes, more preferably greater than 350 flushes when performing a lifespan test using a 50 gram sample of cleaning composition and a 6 litre flush using water having a temperature of 20°C and a hardness of 330 ppm CaCCh. The toilet cleaning composition of the present invention may be provided in a form which facilitates direct attachment to the toilet. For example it may naturally adhere to the surface of the toilet. According to a second aspect of the present invention there is provided a toilet cleaning device comprising a toilet cleaning composition of the first aspect and an attachment element for attaching the device to a toilet. Suitable features of the cleaning composition in the second aspect are as defined in relation to the first aspect of the present invention. Preferably the cleaning composition is provided in solid form. Suitably the device is attachable to the rim of a toilet bowl. The attachment element may be in the form of an arm or hook. The device may comprise a holder for holding the cleaning composition. The holder may be in the form of a housing such as a basket. When the toilet is flushed, water suitably contacts a portion of the cleaning composition, for example, by passing through the basket, to dissolve a portion of the cleaning composition and provide cleaning to the toilet. According to a third aspect of the present invention there is provided a use of a cleaning composition of the first aspect to clean an article or items. In some embodiments the third aspect of the present invention may involve the use of a cleaning composition of the first aspect to clean dishes in an automatic dishwashing machine. In some embodiments the third aspect of the present invention may involve the use of a cleaning composition of the first aspect to launder items in a laundry washing machine. In some embodiments the third aspect of the present invention may involve the use of a cleaning composition of the first aspect to clean a toilet. In such embodiments the cleaning composition may be provided within a device of the second aspect. According to a fourth aspect of the present invention there is provided a method ofcleaning an article or items, the method comprising contacting the cleaning composition of the first aspect with the article or items in the presence of water. In some embodiments the method of the fourth aspect of the present invention may involve playing a portion of the cleaning composition in an automatic dishwashing or laundry washing machine and running a cycle of the machine. In a preferred embodiment the fourth aspect of the present invention involves a method of cleaning a toilet, the method comprising affixing a toilet cleaning composition of the first aspect to a toilet rim or placing the toilet cleaning composition of the first aspect within a toilet cistern. A particular advantage of the present invention is that in addition to cleaning a toilet or items in an automatic dishwashing or laundry washing machine, limescale formation is reduced. According to a fifth aspect of the present invention there is provided a use of the cleaning composition of the first aspect to reduce limescale formation in a toilet, automatic dishwashing machine or laundry washing machine. Preferably the use of the fifth aspect reduces limescale in a toilet. According to a sixth aspect of the present invention there is provided the use of (c) at least one acrylic acid derived polymer to reduce limescale formation during use of a cleaning composition comprising: (a) at least one surfactant compound; and (b) at least one phosphorus free chelating agent. Preferably the sixth aspect of the invention involves the use of (c) at least one acrylic acid derived polymer to reduce limescale formation in a toilet during use of a toilet cleaning composition comprising: (a) at least one surfactant compound; and (b) at least one phosphorus free chelating agent. Preferred features of the third, fourth, fifth and sixth aspects of the invention are as defined in relation to the first aspect. According to a seventh aspect of the present invention there is provided a method of preparing a cleaning composition, the method comprising admixing: (a) at least one surfactant compound; (b) at least one phosphorus free chelating agent; (c) at least one acrylic acid derived polymer; and optionally (d) a filler. Preferred features of the seventh aspect of the present invention are as defined in relation to the first aspect. Solid cleaning compositions may be made for example by extrusion or melt and pour methods. The method of the seventh aspect of the present invention may involve admixing solid ingredients until a homogeneous mixture is obtained, adding any liquid ingredients to form a paste, extruding the paste and cutting the product into desired portions. The invention will now be further described by reference to the following non limiting examples. Example 1 Toilet cleaning compositions 1 to 4 were prepared comprising the components detailed in table 1. The numbers in the table indicate the amounts of each component as a percentage by weight of active material. Compositions 3 and 4 are of the invention. Table 1 Composition: 1 2 3 4 NasCitrate 0.85 3.5 0.85 0.85 STPP 2.1 0 0 0 Na3MGDA - - 0.75 0.75 Perfume 3 3 3 3 NaDDBS 29.75 29.75 29.75 29.75 SLES 1.05 1.05 1.05 1.05 Copolymer A - - - 0.75 Polymer 1 - - 0.75 - Polymer 2 - - - 0.75 Water < 3 < 3 < 3 < 3 Na2SO4 To 100 To 100 To 100 To 100 NasCitrate is the trisodium salt of citric acid STPP is sodium tripolyphosphate NasMGDA is the trisodium salt of methylglycine diacetic acid NaDDBS is sodium dodecyl benzene sulfonate SLES is sodium laureth-2 sulfate Copolymer A is a copolymer of acrylic acid and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) having a weight average molecular weight of 14000 to 18000 Polymer 1 is a fully neutralised homopolymer of acrylic acid having a weight average molecular weight of approximately 4500 Polymer 2 is a partially neutralised homopolymer of acrylic acid having a weight average molecular weight of approximately 4500 Example 2 Compositions 1 to 4 of example 1 were evaluated in a limescale formation test, as follows:. The test involves assessing the efficiency of toilet blocks in terms of limescale prevention, in conditions simulating the use of products. Each block is positioned in a toilet at the same place close to the water inlet. A black enamel tile is placed under the block. A flushing program is initiated using a frequency of 12 flushes per day and the gap between flushes is designed to simulate normal daily use. A controlled experiment has a tile but no toilet block. The experiment is continued until 120 flushes are reached. In each case the cistern is filled with 6 litres of hard water (330 ppm CaCO3) and 20 experts visually assess the limescale formation. The visual assessments involve an absolute and relative assessment, with the untreated tiles considered to have the maximum mark of “6” as indicated in the following scale: Grading Indication 0 No streaks 1 Very slight traces 2 Slight traces 3 Slight to moderate streaks 4 Moderate streaks 5 Moderate to heavy streaks 6 Heavy streaks The relative grading assessment involves comparing the test product with the blank and the methodology used according to NF ISO 8587. 5 The results in table 2 are the average assessments from the 20 panelists. Table 2 Composition 1 2 3 4 Limescale grading 1.7 3.9 0.9 1.5 Performance Satisfactory Weak Good Satisfactory 10

Claims

1. A cleaning composition comprising:(a) at least one surfactant compound;(b) at least one phosphorus free chelating agent; and(c) at least one acrylic acid derived polymer.

2. A cleaning composition according to claim 1 wherein component (a) comprises one or more surfactants selected from anionic surfactants, non ionic surfactants, amphoteric surfactants and cationic surfactants.

3. A cleaning composition according to claim 2 wherein component (a) comprises an anionic surfactant.

4. A cleaning composition according to any preceding claim wherein component (a) comprises an alkyl benzene sulfonate surfactant.

5. A cleaning composition according to any preceding claim wherein component (b) is selected from methylglycinediacetic acid (MGDA), citric acid and mixtures and / or salts thereof.

6. A cleaning composition according to any preceding claim wherein component (c) comprises a homopolymer of acrylic acid, preferably having a weight a weight average molecular weight of from 500 to 30000, preferably from 2000 to 10000.

7. A cleaning composition according to any preceding claim wherein component (c) comprises a copolymer of acrylic acid and one or more further monomers selected from further different acrylic acid based monomers, alkenes, conjugated dienes, styrenes and halo-styrenes (e.g. a-methylstyrene), divinylbenzene, acrolein, vinyl acetate, vinylpyrrolidone, vinylimidazole and maleic anhydride.

8. A cleaning composition according to any preceding claim wherein component (c) comprises a copolymer of acrylic acid and a sulfonated monomer.

9. A cleaning composition according to claim 8 wherein the sulfonated monomer is selected from 2-acrylamido-2-methylpropane sulfonic acid (AMPS), 2-methacrylamido-2-methylpropane sulfonic acid, 4-styrenesulfonic acid, vinylsulfonic acid, 3-allyloxy sulfonic acid, 2-hydroxy-1-propane sulfonic acid (HAPS), 2-sulfoethyl(meth)acrylic acid, 2-sulfopropyl(meth)acrylic acid, 3-sulfopropyl(meth)acrylic acid, 4-sulfobutyl(meth)acrylic acidand salts and mixtures thereof; preferably wherein the sulfonated monomer is 2-acrylamido-2-methylpropane sulfonic acid (AMPS) or a salt thereof.

10. A cleaning composition according to claim 8 or claim 9 wherein the sulfonated copolymer comprises from 50 to 95 wt% (preferably, 60 to 94 wt%; more preferably, 65 to 93 wt%; most preferably, 68 to 90 wt%), based on weight of the sulfonated copolymer, of structural units of acrylic acid; and 5 to 50 wt% (preferably, 6 to 40 wt%; more preferably, 7 to 35 wt%; most preferably, 10 to 32 wt%), based on weight of the sulfonated copolymer, of structural units of sulfonated monomer.

11. A cleaning composition according to claim 8, 9 or 10 wherein the sulfonated copolymer has a weight average molecular weight of from 1000 to 50000, preferably from 12000 to 25000.

12. A cleaning composition according to any preceding claim wherein component (c) comprises an acrylic acid homopolymer and a copolymer of acrylic acid and a sulfonated monomer; preferably in a weight ratio of from 5:1 to 1:5, for example from 2:1 to 1:2.

13. A cleaning composition according to any preceding claim which further comprises (d) a filler.

14. A cleaning composition according to claim 13 wherein component (d) comprises sodium sulfate.

15. A cleaning composition according to any preceding claim which comprises from 5 to 90 wt%, preferably from 20 to 40 wt% component (a); from 0.1 to 10 wt%, preferably from from 0.5 to 5 wt% component (b); from 0.1 to 10 wt%, preferably from 0.5 to 4 wt% component (c); and optionally from 5 to 85 wt%, preferably from 50 to 75 wt% component (d).

16. A cleaning composition according to any preceding claim which is in the form of a solid.

17. A cleaning composition according to any preceding claim which is a toilet cleaning composition.

18. A toilet cleaning device comprising a toilet cleaning composition according to any preceding claim and an attachment element for attaching the device to a toilet.

19. The use of a cleaning composition according to any of claims 1 to 17 to clean an article or items, preferably to clean a toilet.

20. A method of cleaning an article or items, the method comprising contacting a cleaning composition according to any of claims 1 to 17 with the article or items in the presence of water.

521. A method according to claim 20 which involves affixing a cleaning composition according to claim 17 to a toilet rim or placing the cleaning composition according to claim 17 within a toilet cistern.10 22. The use of a cleaning composition according to any of claims 1 to 17 to reducelimescale formation in a toilet, automatic dishwashing machine or laundry washing machine.

23. The use of (c) at least one acrylic acid derived polymer to reduce limescale formation during use of a cleaning composition comprising:15 (a) at least one surfactant compound; and(b) at least one phosphorus free chelating agent.A