Detergent compositions

Abstract

 A granular detergent composition containing about 6% to 18% aluminosilicate cation exchange material (a), about 1% to 8% nitrilotriacetate (b), about 6% to 14% phosphate builder selected from sodium and potassium tripolyphosphates with less than 12% thereof as pyrophosphate, about 5% to 35% bleaching agent, up to 10% organic peroxy acid bleach precursor, and a heavy metal scavenging agent, wherein the percentage quantities of (a) and 2(b) is from 13 to 27. The compositions display improved bleaching, cleaning and fabric damage at low aluminosilicate levels.

Description

[0001] The present invention relates to detergent compositions. In particular, it relates to built laundry detergent compositions having reduced phosphate levels together with excellent cleaning, whiteness maintenance and stain-removal performance as well as improved bleach stability and fabric-care characteristics.

[0002] The role of phosphate detergency builders as adjuncts for organic, water-soluble, synthetic detergents and their value in improving the overall performance of such detergents are well-known. In recent years, however, the use of high levels of phosphate builders, such as the tripolyphosphates, has come under scrutiny because of the suspicion that soluble phosphate species accelerate the eutrophication or ageing process of water bodies. The need exists, therefore for a built laundry detergent composition with reduced phosphate levels but which is comparable to a conventional tripolyphosphate-built composition in overall detergency effectiveness.

[0003] The mechanism whereby detergency builders function to improve the detergency action of water-soluble organic detergent compounds is not precisely known, but appears to depend on a combination of such factors as water-softening action, soil suspension and anti-redeposition effects, clay swelling and peptization and pH adjustment. However, present theory does not allow the prediction of which compounds will serve as effective detergency builders.

[0004] Sodium aluminosilicates, commonly known as zeolites have been proposed for use as phosphate builder substitutes since they are able to soften water by removing calcium ions (see, for example, BE-A-814,874 and BE-A-813581). Zeolites are unable to duplicate the full range of builder functions demonstrated by phosphates, however.

[0005] One way of boosting the overall detergency of low-phosphate formulations is through the use of bleaching auxiliaries such as the inorganic or organic peroxy bleaches and organic bleach activators. Although careful rebalancing of builder and bleach types and levels can indeed provide some improvement in performance, such formulations remain fundamentally weak in three areas, firstly bleach stability, secondly fabric damage characteristics, and thirdly, greasy and particulate soil removal especially at low wash temperatures.

[0006] In EP-A-70,079 it has been proposed to improve the bleach performance of aluminosilicate built compositions by addition thereto of a nitrilotriacetic acid compound. The combined level of aluminosilicate and nitrilotriacetate was said to be critical and corresponded to a relatively high total level in the final product. At high concentrations, however, aluminosilicates and nitrilotriacetates both present significant processing problems, the aluminosilicates raising problems with dispersion stability and pumping characteristics while the nitrilotriacetates raising thermal stability problems. Moreover, high levels of aluminosilicates can also deleteriously effect fabric appearance. Where, on the other hand, the aluminosilicate and nitrilotriacetate levels are reduced into a more acceptable range, bleaching, cleaning performance and fabric damage characteristics are once again adversely effected.

[0007] It has now been discovered that bleaching, cleaning performance and fabric damage characteristics can be significantly improved, even in the context of a relatively low total level of aluminosilicate and nitrilotriacetate, by the addition thereto of a tripolyphosphate builder in defined amounts with a critical maximum limitation on pyrophosphate content. Moreover, it has been further discovered that certain organic peroxy acid bleach precursors of defined chain length are operable in combination with the low-phosphate builder system to provide cleaning performance which is at least equivalent to a fully phosphate-built formulation across the range of wash temperatures with particularly outstanding performance on greasy and particulate soils at low wash temperatures.

[0008] Thus, according to the invention, there is provided a detergent composition comprising

(a) from about 6% to about 18% by weight of a water-insoluble aluminosilicate cation exchange material,

(b) from about 1% to about 8% of an alkali metal salt of nitrilotriacetic acid,

(c) from about 6% to about 14% of phosphate builder, the phosphate builder being selected from sodium and potassium tripolyphosphates and comprising less than about 12% thereof of pyrophosphate,

(d) from about 5% to about 35% of inorganic or organic peroxy bleaching agent,

(e) from 0% to about 10% of organic peroxy acid bleach precursor, and

(f) a heavy metal scavenging agent,

wherein the percentage quantities of (a) + 2 (b) is between about 13 and about 27.

[0009] The compositions of the invention contain a specified detergent builder system and a bleach system. In addition, the compositions will generally include an organic soap or synthetic detergent surfactant material. Highly preferred compositions also contain defined levels of polycarboxylate polymers, alkali metal carbonate and alkali metal silicate designed to provide improved detergency and fabric appearance characteristics.

[0010] The builder system comprises three essential components, a water-insoluble aluminosilicate cation exchange material, an alkali metal salt of nitrilotriacetic acid, and a phosphate builder.

[0011] The aluminosilicate cation exchange material comprises from about 6% to about 18%, preferably from about 7% to about 16%, and more preferably from about 8% to about 14% by weight of the detergent composition. The aluminosilicate can be crystalline or amorphous in character, preferred materials having the unit cell formula I


wherein M is a calcium-exchange cation, z and y are at least 6; the molar ratio of z to y is from about 1.0 to about 0.5 and x is at least 5, preferably from about 7.5 to about 276, more preferably from about 10 to about 264. The aluminosilicate materials are in hydrated form and are preferably crystalline containing from about 10% to about 28%, more preferably from about 18% to about 22% water.

[0012] The aluminosilicate ion exchange materials are further characterized by a particle size diameter of from about 0.1 micron to about 10 microns, preferably from about 0.2 micron to about 4 microns. The term "particle size diameter" herein represents the average particle size diameter of a given ion exchange material as determined by conventional analytical techniques such as, for example, microscopic determination utilizing a scanning electron microscope. The aluminosilicate ion exchange materials herein are usually further characterised by their calcium ion exchange capacity, which is at least about 200 mg. equivalent of cac0₃ water hardness/g of aluminosilicate, calculated on an anhydrous basis, and which generally is in the range of from about 300 mg eq./g to about 352 mg eq./g. The aluminosilicate ion exchange materials herein are still further characterized by their calcium ion exchange rate which is at least about 2 grains Ca⁺⁺/gallon/minute/gram/gallon of aluminosilicate (anhydrous basis), and generally lies within the range of from about 2 grains/gallon/minute/gram/gallon to about 6 grains/gallon/minute/gram/gallon, based on calcium ion hardness. Optimum aluminosilicates for builder purposes exhibit a calcium ion exchange rate of at least about 4 grains/gallon/minute/gram/gallon.

[0013] Aluminosilicate ion exchange materials useful in the practice of this invention are commercially available and can be naturally occurring aluminosilicates or synthetically derived. A method for producing aluminosilicate ion exchange materials is discussed in U.S.-A-3,985,669. Preferred synthetic crystalline aluminosilicate ion exchange materials useful herein are available under the designations Zeolite A, Zeolite B, Zeolite X, Zeolite HS and mixtures thereof. In an especially preferred embodiment, the crystalline aluminosilicate ion exchange material is Zeolite A and has the formula


wherein x is from about 20 to about 30, especially about 27. Zeolite ^X of formula ^Na₈₆ [(Alo₂)₈₆(Sio₂)₁₀₆] .276 H₂0 is also suitable, as well as Zeolite HS of formula Na₆ C(Alo₂)₆(Sio₂)₆] 7.5 ^H₂⁰).

[0014] Suitable nitrilotriacetic acid salts for use herein are the trisodium and tripotassium salts of nitrilotriacetic acid. The acid itself or the disodium or dipotassium salts of the acid can also be used as additive. However, it will be understood that under the pH conditions typically encountered during manufacturing, the nitrilotriacetic acid or salt will generally be converted into fully ionized form.

[0015] The nitrilotriacetic acid salt (measured in trisodium form) constitutes from about 1% to about 8%, preferably from about 3% to 7% by weight of composition. The percentage quantity (b) of nitrilotriacetic acid salt (again measured in trisodium form) and the percentage quantity (a) of aluminosilicate cation exchange material (measured in hydrated form) are such that the sum a + 2b is between about 13 and about 27, preferably between about 14 and about 24, more preferably between about 16 and 21.

[0016] A further essential component of the compositions herein is from about 6% to about 14%, preferably from 8% to about 12% of a phosphate builder. The phosphate builder is selected from sodium and potassium tripolyphosphates and hydrates thereof but is preferably substantially anhydrous or partly hydrated (i.e. to no more than about 60% of its hydration capacity). Phosphate builder content is measured on an anhydrous basis however. Critically, the phosphate builder comprises less than about 12% thereof, preferably less than about 8% thereof of pyrophosphates. Highly preferred is a phosphate builder system which is admixed in dry crystalline form with the remainder of the detergent composition.

[0017] The detergent compositions of the invention also include a bleach system comprising an inorganic or organic peroxy bleaching agent, a heavy metal scavenging agent and in preferred compositions, an organic peroxy acid bleach precursor.

[0018] Suitable inorganic peroxygen bleaches include sodium perborate mono- and tetrahydrate, sodium percarbonate, sodium persilicate and urea-hydrogen peroxide addition products and the clathrate 4Na₂SO₄:2H₂O₂:1NaCl. Suitable organic bleaches include peroxylauric acid, peroxyoctanoic acid, peroxynonanoic acid, peroxydecanoic acid, diperoxydodecanedioic acid, diperoxyazelaic acid, mono- and diperoxyphthalic acid and mono- and diperoxyisophthalic acid. The bleaching agent is present in the compositions of the invention at a level of from about 5% to about 35% preferably from about 10% to about 25% by weight.

[0019] The heavy metal scavenging agent is preferably a water-soluble chelating agent. Preferred are aminopolyacids having four or more acidic protons per molecule. Suitable chelating agents include aminocarboxylate chelating agents such as ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEEDTA), dihydroxyethylethylenediaminediacetic acid (DHEEDDA), diethylenetriaminepentaacetic acid (DETPA), l,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (DCTA) and water-soluble salts thereof, and aminopolyphosphonate chelating agents such as ethylenediaminetetra(methylenephosphonic acid) (EDTMP), diethylenetriaminepenta(methylenephosphonic acid) (DETPMP), nitrilotri(methylenephosphonic acid) (NTMP),hexamethylenediaminetetramethylenephosphonic acid (HMTPM) and water-soluble salts thereof. The above water-soluble sequestrants are generally at a level of from about 0.05% to about 4% preferably from about 0.1% to about 1.0% by weight.

[0020] The heavy metal scavenging agent herein can also be represented by water-soluble smectite-type clays selected from saponites, hectorites and sodium and calcium montmorillorites (sodium and calcium here designating the principal inorganic cation of the clay).

[0021] While any of the above smectite-type clays can be incorporated in the compositions of the invention, particularly preferred smectite-type clays have ion-exchange capacities of at least 50 meq/100g clay, more preferably at least 70 meq/100g (measured, for instance, as described in "The Chemistry and Physics of Clays", p.p. 264-265, Interscience (1979)). Especially preferred materials are as follows:-

Sodium Montmorillonite

[0022] 

Brock

Volclay BC

Gelwhite GP

Thixo-Jel

Ben-A-Gel

Imvite

Sodium Hectorite

[0023] 

Veegum F

Laponite SP

Sodium Saponite

Barasym NAS 100

Calcium Montmorillonite

Soft Clark

Gelwhite L

Lithium Hectorite

Barasym LIH 200

[0024] When present, the above clays are generally added at a level of from about 1% to about 20%, more preferably from about 2% to about 10% by weight of composition. Such clays also provide a fabric softening benefit to the compositions.

[0025] Another suitable heavy metal scavenging agent is water-insoluble, preferably colloidal magnesium silicate or a water-soluble magnesium salt forming magnesium silicate in the aqueous slurry crutcher mix prior to spray-drying. The magnesium silicate or salt is generally added at a level in the range from about 0.015% to about 0.2%, preferably from about 0.03% to about 0.15%, more preferably from about 0.05% to about 0.12% by weight (magnesium basis). Suitable magnesium salts include magnesium sulfate, magnesium sulfate heptahydrate, magnesium chloride and magnesium chloride hexahydrate.

[0026] The compositions of the invention preferably also contain an organic peroxy acid bleach precursor at a level of from about 0.5% to about 10%, preferably from about 1% to about 6% by weight. Suitable bleach precursors are disclosed in UK-A-2040983, and include for example, the peracetic acid bleach precursors such as tetraacetylethylenediamine, tetraacetylmethylenediamine, tetraacetylhexylenediamine, sodium p-acetoxybenzene sulphonate, tetraacetylglycouril, pentaacetylglucose, octaacetyllactose, and methyl o-acetoxy benzoate. Highly preferred bleach precursors, however, have the general formula II


wherein R is an alkyl group containing from 6 to 12 carbon atoms wherein the longest linear alkyl chain extending from and including the carboxyl carbon contains from 5 to 10 carbon atoms and L is a leaving group, the conjugate acid of which has a pK_a in the range from 6 to 13.

[0027] The alkyl group, R, can be either linear or branched and, in preferred embodiments, it contains from 7 to 9 carbon atoms. Preferred leaving groups L have a pK a in the range from about 7 to about 11, more preferably from about 8 to about 10. Examples of leaving groups are those having the formula

and


wherein Z is H, R¹ or halogen, R¹ is an alkyl group having from 1 to 4 carbon atoms, x is 0 or an integer of from 1 to 4 and Y is selected from SO₃M, OS0₃M, CO₂M, NT(R1)3Q and N⁺(R¹)₂-0^- wherein M is H, alkali metal, alkaline earth metal, ammonium or substituted ammonium, and Q is halide or methosulfate.

[0028] The preferred leaving group L has the formula (a) in which Z is H, x is 0 and Y is sulfonate, carboxylate or dimethylamine oxide radical. Highly preferred materials are sodium 3,5,5,-trimethylhexanoyloxybenzene sulfonate, sodium 3,5,5-trimethylhexanoyloxybenzoate, sodium 2-ethylhexanoyl oxybenzenesulfonate, sodium nonanoyl oxybenzene sulfonate and sodium octanoyl oxybenzenesulfonate, the acyloxy group in each instance preferably being p-substituted.

[0029] The bleach activator herein will normally be added in the form of particles comprising finely-divided bleach activator and a binder The binder is generally selected from nonionic surfactants such as the ethoxylated tallow alcohols, polyethylene glycols, anionic surfactants, film forming polymers, fatty acids and mixtures thereof. Highly preferred are nonionic surfactant binders, the bleach activator being admixed with the binder and extruded in the form of elongated particles through a radial extruder as described in European Patent Application No. 62523. Alternatively, the bleach activator particles can be prepared by spray drying as described in British Patent Application No. 8422158.

[0030] The detergent compositions herein contain from about 5% to about 60%, preferably from about 8% to about 30% by weight of an organic surfactant selected from anionic, nonionic, zwitterionic, ampholytic and cationic surfactants, and mixtures thereof. Surfactants useful herein are listed in US-A-4,222,905 and US-A-4,239,659.

[0031] The anionic surfactant can be any one or more of the materials used conventionally in laundry detergents. Suitable synthetic anionic surfactants are water-soluble salts of alkyl benzene sulphonates, alkyl sulphates, alkyl polyethoxy ether sulphates, paraffin sulphonates, alpha-olefin sulphonates, alpha-sulpho-carboxylates and their esters, alkyl glyceryl ether sulphonates, fatty acid monoglyceride sulphates and sulphonates, alkyl phenol polyethoxy ether sulphates, 2-acyloxy alkane-1-sulphonate, and beta-alkyloxy alkane sulphonate.

[0032] A particularly suitable class of anionic surfactants includes water-soluble salts, particularly the alkali metal, ammonium and alkanolammonium salts or organic sulphuric reaction products having in their molecular structure an alkyl or alkaryl group containing from about 8 to about 22, especially from about 10 to about 20 carbon atoms and a sulphonic acid or sulphuric acid ester group. (Included in the term "alkyl" is the alkyl portion of acyl groups). Examples of this group of synthetic detergents which form part of the detergent compositions of the present invention are the sodium and potassium alkyl sulphates, especially those obtained by sulphating the higher alcohols (C8-18) carbon atoms produced by reducing the glycerides of tallow or coconut oil and sodium and potassium alkyl benzene sulphonates, in which the alkyl group contains from about 9 to about 15, especially about 11 to about 13, carbon atoms, in straight chain or branched chain configuration, e.g. those of the type described in U.S-A- 2,220,099 and U.S-A-2,477,383 and those prepared from alkylbenzenes obtained by alkylation with straight chain chloroparaffins (using aluminium trichloride catalysis) or straight chain olefins (using hydrogen fluoride catalysis). Especially valuable are linear straight chain alkyl benzene sulphonates in which the average of the alkyl group is about 11.8 carbon atoms, abbreviated as C₁₁.₈ LAS, and C₁₂-C₁₅ methyl branched alkyl sulphates.

[0033] Other anionic detergent compounds herein include the sodium C_10-18 alkyl glyceryl ether sulphonates, especially those ethers of higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulphonates and sulphates; and sodium or potassium salts of alkyl phenol ethylene oxide ether sulphate containing about 1 to about 10 units of ethylene oxide per molecule and wherein the alkyl groups contain about 8 to about 12 carbon atoms.

[0034] Other useful anionic detergent compounds herein include the water-soluble salts or esters of alpha-sulphonated fatty acids containing from about 6 to 20 carbon atoms in the fatty acid group and from about 1 to 10 carbon atoms in the ester group; water-soluble salts of 2-acyloxy-alkane-l-sulphonic acids containing from about 2 to 9 carbon atoms in the acyl group and from about 9 to about 23 carbon atoms in the alkane moiety; alkyl ether sulphates containing from about 10 to 18, especially about 12 to 16, carbon atoms in the alkyl group and from about 1 to 12, especially 1 to 6, more especially 1 to 4 moles of ethylene oxide; water-soluble salts of olefin sulphonates containing from about 12 to 24, preferably aout 14 to 16, carbon atoms, especially those made by reaction with sulphur trioxide followed by neutralization under conditions such that any sultones present are hydrolysed to the corresponding hydroxy alkane sulphonates; water-soluble salts of paraffin sulphonates containing from about 8 to 24, especially 14 to 18 carbon atoms, and beta-alkyloxy alkane sulphonates containing from about 1 to 3 carbon atoms in the alkyl group and from about 8 to 20 carbon atoms in the alkane moiety.

[0035] The alkane chains of the foregoing non-soap anionic surfactants can be derived from natural sources such as coconut oil or tallow, or can be made synthetically as for example using the Ziegler or Oxo processes. Water solubility can be achieved by using alkali metal, ammonium or alkanolammonium cations; sodium is preferred. Suitable fatty acid soaps can be selected from the ordinary alkali metal (sodium, potassium), ammonium, and alkylolammonium salts of higher fatty acids containing from about 8 to about 24, preferably from about 10 to about 22 and especially from about 16 to about 22 carbon atoms in the alkyl chain. Suitable fatty acids can be obtained from natural sources such as, for instance, from soybean oil, castor oil, tallow, whale and fish oils, grease, lard and mixtures thereof). The fatty acids also can be synthetically prepared (e.g., by the oxidation of petroleum, or by hydrogenation of carbon monoxide by the Fischer-Tropsch process). Resin acids are suitable such as rosin and those resin acids in tall oil. Napthenic acids are also suitable. Sodium and potassium soaps can be made by direct saponification of the fats and oils or by the neutralization of the free fatty acids which are prepared in a separate manufacturing process. Particularly useful are the sodium and potassium salts of the mixtures of fatty acids derived from tallow and hydrogenated fish oil.

[0036] Mixtures of anionic surfactants are particularly suitable herein, especially mixtures of sulfonate and sulfate surfactants in a weight ratio of from about 5:1 to about 1:5, preferably from about 5:1 to about 1:1, more preferably from about 5:1 to about 1.5:1. Especially preferred is a mixture of an alkyl benzene sulfonate having from 9 to 15, especially 11 to 13 carbon atoms in the alkyl radical, the cation being an alkali metal, preferably sodium; and either an alkyl sulfate having from 10 to 20, preferably 12 to 18 carbon atoms in the alkyl radical or an ethoxy sulfate having from 10 to 20, preferably 10 to 16 carbon atoms in the alkyl radical and an average degree of ethoxylation of 1 to 6, having an alkali metal cation, preferably sodium.

[0037] The nonionic surfactants useful in the present invention are condensates of ethylene oxide with a hydrophobic moiety to provide a surfactant having an average hydrophilic-lipophilic balance (HLB) in the range from about 8 to 17, preferably from about 9.5 to 13.5, more preferably from about 10 to about 12.5. The hydrophobic moiety may be aliphatic or aromatic in nature and the length of the polyoxyethylene group which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements.

[0038] Examples of suitable nonionic surfactants include:

1. The polyethylene oxide condensates of-alkyl phenol, e.g. the condensation products of alkyl phenols having an alkyl group containing from 6 to 12 carbon atoms in either a straight chain or branched chain configuration, with ethylene oxide, the said ethylene oxide being present in amounts equal to 3 to 30, preferably 5 to 14 moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in such compounds may be derived, for example, from polymerised propylene, di-isobutylene, octene and nonene. Other examples include dodecylphenol condensed with 9 moles of ethylene oxide per mole of phenol; dinonylphenol condensed with 11 moles of ethylene oxide per mole of phenol; nonylphenol and di-isooctylphenol condensed with 13 moles of ethylene oxide.

2. The condensation product of primary or secondary aliphatic alcohols having from 8 to 24 carbon atoms, in either straight chain or branched chain configuration, with from 2 to about 40 moles, preferably 2 to about 9 moles of ethylene oxide per mole of alcohol. Preferably, the aliphatic alcohol comprises between 9 and 18 carbon atoms and is ethoxylated with between 2 and 9, desirably between 3 and 8 moles of ethylene oxide per mole of aliphatic alcohol. The preferred surfactants are prepared from primary alcohols which are either linear (such as those derived from natural fats or, prepared by the Ziegler process from ethylene, e.g. myristyl, cetyl, stearyl alcohols), or partly branched such as the Lutensols, Dobanols and Neodols which have about 25% 2-methyl branching (Lutensol being a Trade Name of BASF, Dobanol and Neodol being Trade Names of Shell), or _Synperonics, which are understood to have about 50% 2-methyl branching (Synperonic is a Trade Name of I.C.I.) or the primary alcohols having more than 50% branched chain structure sold under the Trade Name Lial by Liquichimica. Specific examples of nonionic surfactants falling within the scope of the invention include Dobanol 45-4, Dobanol 45-7, Dobanol 45-9, _Dobanol 91-2.5, Dobanol 91-3, Dobanol 91-4, Dobanol 91-6, Dobanol 91-8, Dobanol 23-6.5, Synperonic 6, Synperonic 14, the condensation products of coconut alcohol with an average of between 5 and 12 moles of ethylene oxide per mole of alcohol, the coconut alkyl portion having from 10 to 14 carbon atoms, and the condensation products of tallow alcohol with an average of between 7 and 12 moles of ethylene oxide per mole of alcohol, the tallow portion comprising essentially between 16 and 22 carbon atoms. Secondary linear alkyl ethoxylates are also suitable in the present compositions, especially those ethoxylates of the Tergitol series having from about 9 to 15 carbon atoms in the alkyl group and up to about 11, especially from about 3 to 9, ethoxy residues per molecule.

[0039] The compounds formed by condensing ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The molecular weight of the hydrophobic portion generally falls in the range of about 1500 to 1800. Such synthetic nonionic detergents are available on the market under the Trade Name of "Pluronic" supplied by Wyandotte Chemicals Corporation.

[0040] Especially preferred nonionic surfactants for use herein are the C₉-C₁₅ primary alcohol ethoxylates containing 3-8 moles of ethylene oxide per mole of alcohol, particularly the C12-C15 primary alcohols containing 6-8 moles of ethylene oxide per mole of alcohol.

[0041] Cationic surfactants suitable for use herein include quaternary ammonium surfactants and surfactants of a semi-polar nature, for example amine oxides.

[0042] Suitable surfactants of the amine oxide class have the general formula V

wherein R⁵ is a linear or branched alkyl or alkenyl group having 8 to 20 carbon atoms, each R⁶ is independently selected from C_1-4 alkyl and -(C_nH_2nO)_mH where i is an integer from 1 to 6, j is 0 or 1, n is 2 or 3 and m is from 1 to 7, the sum total of C_nH_2nO groups in a molecule being no more than 7.

[0043] In a preferred embodiment R⁵ has from 10 to 14 carbon atoms and each R⁶ is independently selected from methyl and (C_nH_2nO)_mH wherein m is from 1 to 3 and the sum total n of C_nH_2nO groups in a molecule is no more than 5, preferably no more than 3. In a highly preferred embodiment, j is _O and each R⁶ is methyl, and R⁵ is C₁₂-C₁₄ alkyl.

[0044] Another suitable class of amine oxide species is represented by bis-amine oxides having the following substituents.

j : 1 R5: tallow C₁₆-C₁₈ alkyl; palmityl; oleyl; stearyl R₆: hydroxyethyl i : 2 or 3

[0045] A specific example of this preferred class of bis-amine oxides is: N-hydrogenated C₁₆-C₁₈ tallow alkyl-N,N',N'tri-(2-hydroxyethyl) -propylene-1,3-diamine oxide.

[0046] Suitable quaternary ammonium surfactants for use in the present composition can be defined by the general formula VI:

wherein R⁷ is a linear or branched alkyl, alkenyl or alkaryl group having 8 to 16 carbon atoms and each _R⁸ is independently selected from C_1-4 alkyl, C_1-4 alkaryl and -(C_nH_2nO)_m wherein i is an integer from 1 to 6, j is ₀ n or 1, n is 2 or 3 and m is from 1 to 7, the sum total of C_nH_2nO groups in a molecule being no more than 7, and wherein Z represents counteranion in number to give electrical neutrality.

[0047] In a preferred embodiment, R⁷ has from 10 to 14 carbon atoms and each R⁸ is independently selected from methyl and (C_nH_2nO)_mH wherein m is from 1 to 3 and the sum total n of C_nH_2nO groups in a molecule is no more than 5, preferably no more than 3. In a highly preferred embodiment j is 0, R⁸ is selected from methyl, hydroxyethyl and hydroxypropyl and R⁷ is C₁₂-C₁₄ alkyl. Particularly preferred surfactants of this class include C12 alkyl trimethylammonium salts, C₁₄ alkyltrimethylammonium salts, coconutalkyltrimethylammonium salts, coconutalkyldimethyl-hydroxyethylammonium salts, coconutalkyldimethylhydroxy-propylammonium salts, and C12 alkyldihydroxyethylmethyl ammonium salts.

[0048] Another group of useful cationic compounds are the diammonium salts of formula VI in which j is 1, R⁷ is C₁₂-C₁₄ alkyl, each R⁸ is methyl, hydroxyethyl or hydroxypropyl and i is 2 or 3. In a particularly preferred surfactant of this type, R⁷ is coconut alkyl, R 8 is methyl and i is 3.

[0049] In highly preferred compositions, the builder system herein is supplemented by three additional components, polycarboxylate polymers, alkali metal carbonates and alkali metal silicates.

[0050] The polycarboxylate polymers herein are preferably selected from co-polymeric polycarboxylic acids and their salts derived from an unsaturated polycarboxylic acid such as maleic acid, citraconic acid, itaconic acid or mesaconic acid as a first monomer and ethylene, methylvinyl ether, acrylic acid or methacrylic acid as a second monomer, the copolymer comprising at least about 10 mole %, preferably at least about 20 mole % of polycarboxylic acid units and having a weight-average molecular weight of at least about 12,000, preferably at least about 30,000; homopolyacrylates and homopolymethacrylates having a weight-average molecular weight of from about 1000 to about 20,000, preferably from about 1000 to about 10,000; and mixtures thereof. Mixtures are highly preferred in the context of providing excellent bleach stability, detergency and anti-incrustation performance in the context of the low-phosphorous, low aluminosilicate/NTA formulations disclosed herein. Suitable mixtures have a copolymer: homopolymer ratio of from about 1:2 to about 5:1, preferably from about 1:1 to about 5:1, more preferably about 1:1 to 2:1. The total level of polycarboxylate polymer in final product is preferably from about 0.5% to about 5%, more preferably from about 2% to about 4%.

[0051] Weight-average polymer molecular weights can be determined herein by light scattering or by gel permeation chromotography using Waters µ Porasil (RT_M) GPC 60 A² and )4Bondagel (_RT_M) E-125, _E-500 and E-1000 in series, temperature- controlled columns at 40°C against sodium polystyrene sulphonate polymer standards, available from Polymer Laboratories Ltd., Shropshire, UK, the polymer standards being calibrated as their sodium salts, and the eluant being 0.15M sodium dihydrogen phosphate and 0.02M tetramethyl ammonium hydroxide at pH 7.0 in 80/20 water/acetonitrile.

[0052] Alkali metal carbonate is important herein for providing the appropriate in-use solution pH for optimum detergency (from about pH 10 to pH 11, preferably from about pH 10.4 to about pH 10.6, measured as 1% solution). Generally, the compositions of the invention include from about 5% to about 30%, preferably from about 10% to about 25% alkali metal carbonate (anhydrous basis). Alkali metal silicate is preferably included in the compositions of the invention at a level in the range from about 1% to about 4%, more preferably from about 1.5% to about 2.5%. At lower levels, bleaching performance is found to be increasingly degraded; at higher levels, on the other hand, aluminosilicate performance and fabric appearance is detrimentally effected by aluminosilicate particle aggregation.

[0053] The compositions of the invention can be supplemented by all manner of detergent and laundering components, inclusive of suds suppressors, enzymes, fluorescers, photoactivators, bleach catalysts, soil suspending agents, anti-caking agents, pigments, perfumes, fabric conditioning agents etc.

[0054] Suds suppressors are represented by materials of the silicone, wax, vegetable and hydrocarbon oil and phosphate ester varieties. Suitable silicone suds controlling agents include polydimethylsiloxanes having a molecular weight in the range from about 200 to about 200,000 and a kinematic viscosity in the range from about 20 to about 2,000,000 mm²/s, preferably from about 3000 to about 30,000 mm ² /s, and mixtures of siloxanes and hydrophobic silanated (preferably trimethylsilanated) silica having a particle size in the range from about 10 millimicrons to about 20 millimicrons and a specific surface area above about 50 m²/g. Suitable waxes include microcrystalline waxes having a melting point in the range from about 65°C to about 100°C, a molecular weight in the range from about 400-1000, and a penetration value of at least 6, measured at 77°F by ASTM-D1321, and also paraffin waxes, synthetic waxes and natural waxes. Suitable phosphate esters include mono- and/or di-C₁₆-C₂₂ alkyl or alkenyl phosphate esters, and the corresponding mono- and/or di alkyl or alkenyl ether phosphates containing up to 6 ethoxy groups per molecule.

[0055] Enzymes suitable for use herein include those discussed in US-A-3,519,570 and US-A-3,533,139 to McCarty and McCarty et al issued July 7, 1970 and January 5, 1971, respectively. Suitable fluorescers include Blankophor MBBH (Bayer AG) and Tinopal CBS and EMS (Ciba Geigy). Photoactivators are discussed in EP-A-57088, highly preferred materials being zinc phthalocyanine tri- and tetra-sulfonates. Suitable fabric conditioning agents include di-C₁₂-C₂₄ alkyl or alkenyl amines and ammonium and quaternary ammonium salts. Suitable bleach catalysts are discussed in European Patent Application No. 72166 and European Patent Application No. 84302774.9.

[0056] Antiredeposition and soil suspension agents suitable herein include cellulose derivatives such as methylcellulose, carboxymethylcellulose and hydroxyethylcellulose.

[0057] The compositions of the invention are preferably prepared by spray-drying an aqueous slurry comprising the aluminosilicate and, where present, alkali metal silicate and anionic surfactant. The nitrilotriacetate can also be spray-dried or added separately to the spray-dried base granules. Tripolyphosphate builder and, where present, carbonate, are also separately dry-mixed with the spray-dried base granules. The aqueous slurry is mixed at a temperature in the range from about 45-90°C and the water-content of the slurry adjusted to a range of about 25% to about 50%. Spray drying is undertaken with a drying gas inlet temperature of from about 250-390°C, preferably about 275-350°C, providing a final moisture content in the range of from about 8% to 14% by weight.

[0058] In the Examples which follow, the abbreviations used have the following designations:-

C₁₂LAS : Sodium linear C₁₂ benzene sulphonate

TAS : Sodium tallow alcohol sulphate

C_12/14AS : C_12/14 alcohol sulphate, sodium salt

TAE_n : Hardened tallow alcohol ethoxylated with n moles of ethylene oxide per mole of alcohol

C₁₂TMAB : C₁₂ alkyl trimethyl ammonium bromide

Dobanol 45E7 : A C₁₄-₁₅ primary alcohol condensed with 7 moles of ethylene oxide.

TAED : Tetraacetyl ethylene diamine

PAG : Penta acetyl glucose

AOBS : Sodium p-acetoxy benzene sulphonate

NOBS : Sodium nonanoyl oxybenzenesulphonate

INOBS : Sodium 3,5,5 trimethyl hexanoyl , oxybenzene sulphonate

INOBA : Sodium 3,5,5 trimethyl hexanoyl oxybenzene carboxylate

EHOBS : Sodium 2-ethyl hexanoyl oxybenzene sulphonate

Silicate : Sodium silicate having an Si0₂:Na₂0 ratio of 1:6

Sulphate : Anhydrous sodium sulphate

Carbonate : Anhydrous sodium carbonate

CMC : Sodium carboxymethyl cellulose

Silicone : Comprising 0.14 parts by weight of an 85:15 by weight mixture of silanated silica and silicone, granulated with 1.3 parts of sodium tripolyphosphate, and 0.56 parts of tallow alcohol condensed with 25 molar proportions of ethylene oxide

NTA : Sodium nitrilotriacetate

PC1 : Copolymer of 3:7 maleic/acrylic acid, average molecular weight about 70,000, as sodium salt

PC2 : Polyacrylic acid, average molecular weight about 4,500, as sodium salt

Phosphate : Anhydrous pentasodium tripolyphosphate (ortho/pyro content = 3%)

Perborate : Sodium perborate tetrahydrate of nominal formula NaB0₂.3H₂0.H₂0₂

Enzyme : Protease

EDTA : Sodium ethylene diamine tetra acetate

Brightener : Disodium 4,4'-bis(2-morpholino-4-anilino-s-triazin-6-ylamino) stilbene-2:2'-disulphonate

DETPMP : Diethylene triamine penta(methylene, phosphonic acid), marketed by Monsanto under the Trade name Dequest 2060

EDTMP : Ethylenediamine tetra (methylene phosphonic acid), marketed by Monsanto, under the Trade name Dequest 2041

Clay : Sodium montmorillonite

Examples I to VIII

[0059] Granular detergent compositions are prepared as follows. A base powder composition is first prepared by mixing all components except Dobanol 45E7, bleach, bleach activator, enzyme, suds suppressor, phosphate and carbonate in a crutcher as an aqueous slurry at a temperature of about 55°C and containing about 35% water. The slurry is then spray dried at a gas inlet temperature of about 330°C to form base powder granules. The bleach activator, where present, is then admixed with TAE₂₅ as binder and extruded in the form of elongate particles through a radial extruder as described in European Patent Application Number 62523. The bleach activator noodles, bleach, enzyme, suds suppressor, phosphate and carbonate are then dry-mixed with the base powder composition and finally Dobanol 45E7 is sprayed into the final mixture.

EXAMPLES

[0060] 

[0061] The above compositions are low phosphate detergent compositions displaying excellent bleach stability, fabric care and detergency performance across the range of wash temperatures with particularly outstanding performance in the case of Examples I to IV on greasy and particulate soils at low wash temperatures.

Claims

l. A granular detergent composition characterised by:

(a) from about 6% to about 18% by weight of a water-insoluble aluminosilicate cation exchange material,

(b) from about 1% to about 8% of an alkali metal salt of nitrilotriacetic acid,

(c) from about 6% to about 14% of phosphate builder, the phosphate builder being selected from sodium and potassium tripolyphosphates and comprising less than about 12% thereof of pyrophosphate,

(d) from about 5% to about 35% of inorganic or organic peroxy bleaching agent,

(e) from 0% to about 10% of organic peroxy acid bleach precursor, and

(f) a heavy metal scavenging agent,

wherein the percentage quantities of (a) + 2 (b) is between about 13 and about 27.

2. A composition according to Claim 1 wherein the quantities of (a) + 2(b) is between about 14 and about 24, preferably between about 16 and about 21.

3. A composition according to Claim 1 or 2 comprising from about 7% to about 16%, preferably from about 8% to about 14% water-soluble aluminosilicate cation exchange material.

4. A composition according to any of Claims 1 to 3 wherein the cation-exchange material has the general formula I
M_z[(Alo₂)_z (^Si0₂)y)7 x H₂0 I
wherein M is a calcium-exchange cation, z and y are at least 6; the molar ratio of z to y is in the range from about 1.0 to about 0.5; and x is from about 10 to about 264; the aluminosilicate having a calcium ion exchange capacity of at least 200 milligrams equivalent of CaC0_3/gram, a calcium ion exchange rate of at least about 2 grains.of Ca2+/gallon/minute/gram/gallon, and a particle size diameter of from about 0.1 microns to about 10 microns.

5. A composition according to any of Claims 1 to 4 comprising from about 3% to about 7% of the nitrilotriacetic acid salt.

6. A composition according to any of Claims 1 to 5 comprising from about 8% to about 12% of the phosphate builder and wherein the phosphate builder comprises less than about 8% thereof of pyrophosphate.

7. A composition according to any of Claims 1 to 6 comprising at least 0.5% organic peroxyacid bleach precursor.

8. A composition according to Claim 7 wherein the organic peroxyacid bleach precursor has the general formula II


wherein R is an alkyl group containing from 6 to 12 carbon atoms wherein the longest linear alkyl chain extending from and including the carboxyl carbon contains from 5 to 10 carbon atoms and L is a leaving group, the conjugate acid of which has a pK a in the range from 6 to 13.

9. A composition according to any of Claims 1 to 8 wherein the heavy metal scavening agent is selected from water-soluble aminopolycarboxylates and aminopolyphosphonates having at least four acidic protons per molecule or a water-insoluble smectite-type clay selected from saponites, hectorites and sodium and calcium montmorillonites.

10. A composition according to any of Claims 1 to 9 additionally comprising from about 0.5% to about 5% of a polycarboxylate polymer. '

11. A composition according to any of Claims 1 to 10 additionally comprising from about 0.5% to about 5% of alkali metal silicate.

12. A composition according to any of Claims 1 to 11 comprising from about 5% to about 60% of organic surfactant selected from anionic, nonionic, zwitterionic, ampholytic and cationic surfactants and mixtures thereof.