GB2290085A - Preparation of particulate detergent composition - Google Patents

Abstract

A process for making a particulate detergent composition comprising the steps of: (a) the application of an acidic solution of an organo diphosphonate to alkali metal silicate free inert carrier particles comprising a solid salt, by spraying of said acidic solution onto said inert carrier particles; and (b) admixing the particles formed in step (a) with particles containing a alkali metal silicate.

Description

PROCESS FOR MAKING PARTICULATE DETERGENT COMPOSITIONS This invention relates to a process for making particulate detergent compositions, particularly automatic dishwashing compositions, comprising a diphosphonate component and an alkali metal silicate component.

Detergent compositions comprising alkali metal silicate and diphosphonate components are well known in the art. The use of such compositions in automatic dishwashing is also known.

Alkali metal silicates are typically incorporated in detergent compositions to provide a source of alkalinity, and for their builder and anticorrosion properties.

Organo diphosphonic acids, and their salts particularly ethane l-hydroxy-1,1 diphosphonic acid (HEDP) and the sodium and potassium salts thereof, are incorporated in detergent compositions to provide builder and chelation capacity. Certain diphosphonates, particularly HEDP, are of particular utility in machine washing methods in preventing the formation/build up of insoluble deposits/incrustrations on the surfaces of the items in the wash or the interior of the washing machine.Such insoluble depositsfmcrustrations often comprise Group (II) carbonate salts, and tend to be a particular problem when the wash solution contains high levels of either calcium or magnesium ions, or carbonate ions which may be present either as natural components of the inlet water to the washing machine or be derived from other components, such as calcium carbonate builder, of the detergent composition.

The problem of deposits formation is especially troublesome in automatic dishwashing methods where the deposits can form as spots and films on the articles in the wash. The utility of organo diphosphonates in ameliorating this problem has been recognised in the art.

Organo diphosphonate components are readily available as solutions of either the acid, or of soluble salts such as the sodium and potassium salts. These solutions may be incorporated into particulate detergent compositions by a number of methods including spraying the solution onto the various particulate components of the composition or by agglomerating with the particular components, the solution here acting as a liquid binder for the agglomerates thereby formed. In general, spray-on processes are simpler and require less specialised, and hence less expensive, machinery than agglomeration processes and for this reason such processes are preferred.

The Applicants have found that to facilitate the prevention ofthe formation of deposits/incrustrations it is desirable to have rapid release of the organo diphosphonate component to the wash solution. Such rapid release is enabled where said component has been incorporated by a spraying on process, in that the component is present essentially as a (partial) coating ofthe various particulate components. The spraying of a solution containing HEDP onto a particulate detergent composition has been disclosed in the Applicant's copending UK Application No. 9326281.4.

Where the organo diphosphonate component is incorporated by spraying an acidic solution ofthis component onto a particulate detergent matrix containing alkali metal silicate components an undesirable polymerisation reaction can be initiated leading to the formation of insolubles, which in turn can lead to reduced detergency performance of the composition.

The Applicants have now found that the enhanced deposit formation capability associated with the spraying-on process may be achieved, without the negatives associated with the undesirable reaction ofthe organo diphosphonate with the alkali metal silicate, where the organo diphosphonate component is incorporated by spraying an acidic solution thereof onto a particulate inert carrier followed by separate dry mixing of the particles thereby obtained with alkali metal silicate containing particles. One or more optional drying steps can be included prior to the dry mixing step. In an alternative process the acidic solution may be replaced by a partially neutralised or wholly neutralised solution of the organo diphosphonate. Suitable inert carriers have been found to include certain carbonate, sulphate and citrate salts.

The Applicant's European Patent Application No.92905212.4 discloses a process for making a granular detergent composition comprising the steps of forming a fluid mix comprising an aqueous mixture of a chelant (e.g. HEDP) and an organic dispersant, cocontacting the fluid premix with solid-form water soluble nonphosphorus salts to form a particulate agglomerate, and mixing the particulate agglomerates thereby formed, with solid form particulate admixes comprising bleach active salts, and optionally alkali metal silicates. There is no disclosure provided of the spraying on of the chelant component to the water soluble nonphosphorus salts, as a method of cocontacting these components.

Such a spraying on step is essential to the current invention which is hence distinct from the disclosure provided by this document. Furthermore, no recognition is provided by this document of the undesirable reaction of silicates with acidic solutions of organo diphosphonates. Indeed the document contemplates only the possible use of sodium and potassium salts of the organo diphosphonate components therein disclosed.

There is provided a process for making a particulate detergent composition comprising the steps of: (a) the application of an acidic solution of an organo diphosphonate to alkali metal silicate free inert carrier particles comprising a solid salt, by spraying of said acidic solution onto said inert carrier particles; and (b) admixing the particles formed in step (a) with particles containing an alkali metal silicate.

The spraying on of the organo diphosphonate provides for rapid release, and hence effective performance, of this component in a machine washing method. The separate addition of the alkali metal silicate component prevents undesirable polymerisation reactions between the organo diphosphonate and silicate components.

DETAILED DESCRIPTION OF THE INVENTION A two step process for making particulate detergent compositions is provided. The first step involves the spraying of an acidic solution of an organo disphonate onto inert carrier particles. The inert carrier particles comprise a solid salt and contain no alkali metal silicate. The second step of the process involves admixing, using any suitable mixing equipment, the particles resulting from the first step with particles comprising an alkali metal silicate.

An additional, highly preferred, step involves the drying, using any suitable drying apparatus, of the particles formed in the first step prior to the second admixing step.

Such drying can provide for enhanced storage stability of the composition.

Acidic organo diphosphonate solution The organo diphosphonate solution may be of any desired concentration but preferably comprises from 1% to 99%, more preferably 10% to 80% by weight ofthe organo diphosphonic acid component. The solution is acidic, and preferably has a pH of from 0.5 to 7, more preferably from 0.8 to 3.

The organo diphosphonate component is preferably incorporated to provide a level of from 0.005% to 20%, more preferably from 0.1% to 10%, most preferably from 0.2% to 5% by weight of the detergent compositions.

By organo diphosphonate it is meant herein an organo diphosphonate which does not contain nitrogen as part of its chemical structure. This definition therefore excludes the organo aminophosphonates, which however may be included in compositions ofthe invention as heavy metal ion sequestrants.

The organo diphosphonate component may be incorporated into the solution in its acid form or in the form of one of its salts or complexes with a suitable counter cation and reference hereinafter to said component implicitly includes reference to said acid form, salts or complexes. Preferably any salts/complexes are water soluble, with the alkali metal and alkaline earth metal salts/complexes being especially preferred.

The organodiphosphonate is preferably a C1-C4 diphosphonate, more preferably a C2 diphosphonate, such as ethylene diphosphonate, or most preferably ethane 1-hydroxy1, 1-diphosphonate (HEDP).

Acidification agents such as HCl may be used to adjust the pH ofthe organo diphosphonate solution.

Inert carrier particles The inert carrier particles contain a solid salt, but do not contain metal silicate. The carrier particle is inert in the sense that it does not react with the organo diphosphonate solution to produce undesirable insoluble components. The particles preferably have a particle size of from 150m to 1400calm, more preferably from 2501lm to 1000calm.

The solid salt can be selected from essentially any of the non-silicate salts commonly employed in detergent compositions. The salt may be water-soluble or water-insoluble, but where the proposed application is to machine dishwashing compositions, where insoluble salt deposition on articles in the wash is a problem, it is most preferred that the salt is water-soluble. The salt preferably also functions as detergency builder material in the wash solution. The salt assists in providing the desired density and bulk to the detergent granules herein.

Examples of water-soluble inorganic salts include the alkali metal, ammonium or substituted ammonium chlorides, fluorides and sulfates. The alkali metal, and especially sodium, salts of the above are preferred. Sodium sulfate is typically used in detergent granules and is a particularly preferred salt.

Other useful salts include the compounds commonly known as detergent builder materials. Builders are generally selected from the alkali metal, ammonium or substituted ammonium phosphates, polyphosphates, phosphonates, polyphosphonates, carbonates, bicarbonates, sesquicarbonates, citrates, borates, and polyhydroxysulfonates. Preferred are the alkali metal, especially sodium, salts of the above.

Specific examples of inorganic phosphate builders are sodium and potassium tripolyphosphate, pyrophosphate, polymeric metaphosphate having a degree of polymerization of from about 6 to 21, and orthophosphate.

The organo diphosphonate is preferably sprayed on to the inert carrier particles such that the weight or ratio of inert carrier particle:organo diphosphonate is from 4:1 to 199:1, preferably 9:1 to 99:1.

Alkali metal silicate particles Suitable alkali metal silicates include the water soluble sodium silicates with an SiO2:Na2O ratio of from 1.0 to 2.8, with ratios of from 1.6 to 2.4 being preferred, and 2.0 ratio being most preferred. The silicates may be in the form of either the anhydrous salt or a hydrated salt. Sodium silicate with an SiO2:Na2O ratio of 2.0 is the most preferred silicate.

Silicates are preferably incorporated in the compositions at a level of from 1% to 50%, preferably from 5% to 45%, most preferably from 10% to 40% by weight.

Additional detergent components The inert carrier particles, the alkali metal silicate particles and the detergent compositions as a whole may contain additional detergent components. These may be incorporated by any suitable means including dry mixing, as agglomerates and as spray ons.

Preferred additional components are selected from surfactants, additional builders, organic polymeric compounds including polyacrylates, lime soap dispersants, bleaching agents selected from chlorine bleaches, inorganic perhydrate salts, bleach activators and organic peroxyacids, heavy metal ion sequestrants, enzymes including proteolytic, amylolytic and lipolytic enzymes, enzyme stabilizers, corrosion inhibitors, suds suppressors, solvents, hydrotropes, perfumes, colours and fillers.

Detergent Builder Svstem A preferred component of the detergent compositions of is a detergent builder system, wherein said detergent builder system is preferably present at a level of from 0.5% to 80% by weight, more preferably from 1% to 60% by weight, most preferably from 2% to 40% weight ofthe compositions.

The detergent builder system is preferably water-soluble, and can, for example, contain builder compound selected from monomeric polycarboxylates or their acid forms, homo or copolymeric polycarboxylic acids or their salts in which the polycarboxylic acid comprises at least two carboxylic radicals separated from each other by not more that two carbon atoms, the alkali metal, ammonium or alkanonammonium salts of bicarbonates, borates, phosphates, and mixtures of any of the foregoing.

Preferably, the detergent builder system contains no phosphate builder compound.

Suitable water-soluble monomeric or oligomeric carboxylate builders can be selected from a wide range of compounds but such compounds preferably have a first carboxyl logarithmic acidity/constant (pK1) of less than 9, preferably of between 2 and 8.5, more preferably of between 4 and 7.5.

The carboxylate or polycarboxylate builder can be momomeric or oligomeric in type although monomeric polycarboxylates are generally preferred for reasons of cost and performance. Monomeric and oligomeric builders can be selected from acyclic, alicyclic, heterocyclic and aromatic carboxylates.

Suitable carboxylates containing one carboxy group include the water soluble salts of lactic acid, glycolic acid and ether derivatives thereof as disclosed in Belgian Patent Nos. 831,368, 821,369 and 821,370. Polycarboxylates containing two carboxy groups include the water-soluble salts of succinic acid, malonic acid, (ethylenedioxy) diacetic acid, maleic acid, diglycolic acid, tartaric acid, tartronic acid and fumaric acid, as well as the ether carboxylates described in German Offenlegenschrift 2,446,686, and 2,446,687 and U.S. Patent No. 3,935,257 and the sulfinyl carboxylates described in Belgian Patent No. 840,623.

Polycarboxylates containing three carboxy groups include, in particular, watersoluble citrates, aconitrates and citraconates as well as succinate derivatives such as the carboxymethyloxysuccinates described in British Patent No. 1,379,241, lactoxysuccinates described in British Patent No. 1,389,732, and aminosuccinates described in Netherlands Application 7205873, and the oxypolycarboxylate materials such as 2-oxa-1,1,3-propane tricarboxylates described in British Patent No. 1,387,447.

Polycarboxylates containing four carboxy groups include oxydisuccinates disclosed in British Patent No. 1,261,829, 1,1,2,2-ethane tetracarboxylates, 1,1,3,3-propane tetracarboxylates and 1,1,2,3-propane tetracarboxylates.

Polycarboxylates containing sulfo substituents include the sulfosuccinate derivatives disclosed in British Patent Nos. 1,398,421 and 1,398,422 and in U.S.

Patent No. 3,936,448, and the sulfonated pyrolysed citrates described in British Patent No. 1,439,000.

Alicyclic and heterocyclic polycarboxylates include cyclopentane-cis,cis,cistetracarboxylates, cyclopentadienide pentacarboxylates, 2,3,4,5-tetrahydrofuran cis, cis, cis-tetracarboxylates, 2,5-tetrahydrofuran- cis - dicarboxylates, 2,2,5,5 tetrahydrofuran - tetracarboxylates, 1,2,3,4,5, 6-hexane - hexacarboxylates and carboxymethyl derivatives of polyhydric alcohols such as sorbitol, mannitol and xylitol. Aromatic polycarboxylates include mellitic acid, pyromellitic acid and the phthalic acid derivatives disclosed in British Patent No. 1,425,343.

Of the above, the preferred polycarboxylates are hydroxycarboxylates containing up to three carboxy groups per molecule, more particularly citrates.

The parent acids of the monomeric or oligomeric polycarboxylate chelating agents or mixtures thereof with their salts, e.g. citric acid or citrate/citric acid mixtures are also contemplated as components of builder systems of the detergent compositions in accordance with the present invention.

Specific examples of carbonate builder compound include the alkali metal carbonates, bicarbonates and sesquicarbonates. Carbonate builder compound may be present only as a minor component of the builder system.

Specific examples of phosphate builders are the alkali metal tripolyphosphates, sodium, potassium and ammonium pyrophosphate, sodium and potassium and ammonium pyrophosphate, sodium and potassium orthophosphate, sodium polymeta/phosphate in which the degree of polymerization ranges from about 6 to 21, and salts of phytic acid. Preferably, no phosphate builder compound is present.

The detergent compositions of the invention the compositions may also include less water soluble builders although preferably their levels of incorporation are minimized. Examples of such less water soluble builders include the crystalline layered silicates, and the largely water insoluble sodium aluminosilicates.

Surfactant system A preferred component ofthe detergent compositions ofthe invention is a surfactant system comprising surfactant selected from anionic, cationic, nonionic ampholytic and zwitterionic surfactants and mixtures thereof. The surfactant system is typically present at a level of from 0.5% to 40% by weight, more preferably 1% to 30% by weight, most preferably from 1.5% to 20% by weight of the compositions.

In one preferred execution of the invention the surfactant system consists of low foaming nonionic surfactant, preferably selected from ethoxylated and/or propoxylated nonionic surfactants, more preferably selected from nonionic ethoxylated/ propoxylated fatty alcohol surfactants.

In an alternative preferred execution of the invention the surfactant system comprises high foaming anionic surfactant, particularly alkyl ethoxysulfate surfactant, in combination with a suds suppressing system.

Anionic surfactant Essentially any anionic surfactants useful for detersive purposes can be included in the compositions. These can include salts (including, for example, sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts) of the anionic sulfate, sulfonate, carboxylate and sarcosinate surfactants.

Other anionic surfactants include the isethionates such as the acyl isethionates, N-acyl taurates, fatty acid amides of methyl tauride, alkyl succinates and sulfosuccinates, monoesters of sulfosuccinate (especially saturated and unsaturated C1 2-C18 monoesters) diesters of sulfosuccinate (especially saturated and unsaturated C6-C14 diesters), N-acyl sarcosinates. Resin acids and hydrogenated resin acids are also suitable, such as rosin, hydrogenated rosin, and resin acids and hydrogenated resin acids present in or derived from tallow oil.

Anionic sulfate surfactant Anionic sulfate surfactants suitable for use herein include the linear and branched primary alkyl sulfates, alkyl ethoxysulfates, fatty oleyl glycerol sulfates, alkyl phenol ethylene oxide ether sulfates, the C5-C17 acyl-N-(C1-C4 alkyl) and -N-(C1-C2 hydroxyalkyl) glucamine sulfates, and sulfates of alkylpolysaccharides such as the sulfates of alkylpolyglucoside (the nonionic nonsulfated compounds being described herein).

Alkyl ethoxysulfate surfactants are preferably selected from the group consisting of the C6-C18 alkyl sulfates which have been ethoxylated with from about 0.5 to about 20 moles of ethylene oxide per molecule. More preferably, the alkyl ethoxysulfate surfactant is a C6-C18 alkyl sulfate which has been ethoxylated with from about 0.5 to about 20, preferably from about 0.5 to about 5, moles of ethylene oxide per molecule.

Anionic sulfonate surfactant Anionic sulfonate surfactants suitable for use herein include the salts of Cg-C20 linear alkylbenzene sulfonates, alkyl ester sulfonates, C6-C22 primary or secondary alkane sulfonates, C6-C24 olefin sulfonates, sulfonated polycarboxylic acids, alkyl glycerol sulfonates, fatty acyl glycerol sulfonates, fatty oleyl glycerol sulfonates, and any mixtures thereo Anionic carboxvlate surfactant Anionic carboxylate surfactants suitable for use herein include the alkyl ethoxy carboxylates, the alkyl polyethoxy polycarboxylate surfactants and the soaps ('alkyl carboxyls'), especially certain secondary soaps as described herein.

Preferred alkyl ethoxy carboxylates for use herein include those with the formula RO(CH2CH20)X CH2C00-M+ wherein R is a C6 to C18 alkyl group, x ranges from 0 to 10, and the ethoxylate distribution is such that, on a weight basis, the amount of material where x is 0 is less than about 20 %, and the amount of material where x is greater than 7, is less than about 25 %, the average x is from about 2 to 4 when the average R is C13 or less, and the average x is from about 3 to 10 when the average R is greater than C13, and M is a cation, preferably chosen from alkali metal, alkaline earth metal, ammonium, mono-, di-, and tri-ethanol-ammonium, most preferably from sodium, potassium, ammonium and mixtures thereof with magnesium ions. The preferred alkyl ethoxy carboxylates are those where R is a C12 to C18 alkyl group.

Alkyl polyethoxy polycarboxylate surfactants suitable for use herein include those having the formula RO-(CHR1-CHR2-O)-R3 wherein R is a C6 to C18 alkyl group, x is from 1 to 25, R1 and R2 are selected from the group consisting of hydrogen, methyl acid radical, succinic acid radical, hydroxysuccinic acid radical, and mixtures thereof, wherein at least one R1 or R2 is a succinic acid radical or hydroxysuccinic acid radical, and R3 is selected from the group consisting of hydrogen, substituted or unsubstituted hydrocarbon having between 1 and 8 carbon atoms, and mixtures thereof.

Preferred soap surfactants are secondary soap surfactants which contain a carboxyl unit connected to a secondary carbon. The secondary carbon can be in a ring structure, e.g.

as in p-octyl benzoic acid, or as in alkyl-substituted cyclohexyl carboxylates. The secondary soap surfactants should preferably contain no ether linkages, no ester linkages and no hydroxyl groups. There should preferably be no nitrogen atoms in the headgroup (amphiphilic portion). The secondary soap surfactants usually contain 11-13 total carbon atoms, although slightly more (e.g., up to 16) can be tolerated, e.g. p-octyl benzoic acid.

The following general structures further illustrate some of the preferred secondary soap surfactants: A. A highly preferred class of secondary soaps comprises the secondary carboxyl materials of the formula R3 CH(R4)COOM, wherein R3 is CH3(CH2)x and R4 is CH3(CH2)y, wherein y can be O or an integer from 1 to 4, x is an integer from 4 to 10 and the sum of(x + y) is 6-10, preferably 7-9, most preferably 8.

B. Another preferred class of secondary soaps comprises those carboxyl compounds wherein the carboxyl substituent is on a ring hydrocarbyl unit, i.e., secondary soaps of the formula R5-R6-COOM, wherein R5 is C7-C10, preferably C8-C9, alkyl or alkenyl and R6 is a ring structure, such as benzene, cyclopentane and cyclohexane. (Note: R5 can be in the ortho, meta or para position relative to the carboxyl on the ring.) C. Still another preferred class of secondary soaps comprises secondary carboxyl compounds of the formula CH3 (CHR)k-(CH2)m-(CHR)n-CH(COOM)(CHR)o-(CH2)p-(CHR)q-CH3, wherein each R is C1-C4 alkyl, wherein k, n, o, q are integers in the range of 0-8, provided that the total number of carbon atoms (including the carboxylate) is in the range of 10 to 18.

In each of the above formulas A, B and C, the species M can be any suitable, especially water-solubilizing, counterion.

Especially preferred secondary soap surfactants for use herein are water-soluble members selected from the group consisting of the water-soluble salts of 2-methyl- 1 -undecanoic acid, 2-ethyl-1-decanoic acid, 2-propyl-1-nonanoic acid, 2-butyl-1-octanoic acid and 2 pentyl-1-heptanoic acid.

Alkali metal sarcosinate surfactant Other suitable anionic surfactants are the alkali metal sarcosinates of formula R-CON (R1) CH2 COOM, wherein R is a C5-C17 linear or branched alkyl or alkenyl group, R1 is a C1-C4 alkyl group and M is an alkali metal ion. Preferred examples are the myristyl and oleyl methyl sarcosinates in the form of their sodium salts.

Nonionic surfactant Essentially any anionic surfactants useful for detersive purposes can be included in the compositions. Exemplary, non-limiting classes of useful nonionic surfactants are listed below.

Nonionic polvhvdroxv fattv acid amide surfactant Polyhydroxy fatty acid amides suitable for use herein are those having the structural formula R2CONR1Z wherein : R1 is H, C1-C4 hydrocarbyl, 2-hydroxy ethyl, 2-hydroxy propyl, or a mixture thereof preferable C1-C4 alkyl, more preferably C1 or C2 alkyl, most preferably C1 alkyl (i.e., methyl); and R2 is a C5-C31 hydrocarbyl, preferably straight-chain Cs-C1g alkyl or alkenyl, more preferably straight-chain Cg-C17 alkyl or alkenyl, most preferably straight-chain C1 1-C17 alkyl or alkenyl, or mixture thereof; and Z is a polyhydroxyhydrocarbyl having a linear hydrocarbyl chain with at least 3 hydroxyls directly connected to the chain, or an alkoxylated derivative (preferably ethoxylated or propoxylated) thereof.Z preferably will be derived from a reducing sugar in a reductive amination reaction; more preferably Z is a glycityl.

Nonionic condensates of alkvl phenols The polyethylene, polypropylene, and polybutylene oxide condensates of alkyl phenols are suitable for use herein. In general, the polyethylene oxide condensates are preferred.

These compounds include the condensation products of alkyl phenols having an alkyl group containing from about 6 to about 18 carbon atoms in either a straight chain or branched chain configuration with the alkylene oxide.

Nonionic ethoxvlated alcohol surfactant The alkyl ethoxylate condensation products of aliphatic alcohols with from about 1 to about 25 moles of ethylene oxide are suitable for use herein. The alkyl chain of the aliphatic alcohol can either be straight or branched, primary or secondary, and generally contains from 6 to 22 carbon atoms. Particularly preferred are the condensation products of alcohols having an alkyl group containing from 8 to 20 carbon atoms with from about 2 to about 10 moles of ethylene oxide per mole of alcohol.

Nonionic ethoxvlated/propoxvlated fatty alcohol surfactant The ethoxylated C6-C18 fatty alcohols and C6-C18 mixed ethoxylated/propoxylated fatty alcohols are preferred surfactants for use herein, particularly where water soluble.

Preferably the ethoxylated fatty alcohols are the C1 0-C18 ethoxylated fatty alcohols with a degree of ethoxylation of from 3 to 50, most preferably these are the C 12-c 18 ethoxylated fatty alcohols with a degree of ethoxylation from 3 to 40. Preferably the mixed ethoxylated/propoxylated fatty alcohols have an alkyl chain length of from 10 to 18 carbon atoms, a degree of ethoxylation of from 3 to 30 and a degree of propoxylation offrom 1 to 10.

Nonionic EO/PO condensates with propylene glvcol The condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol are suitable for use herein. The hydrophobic portion of these compounds preferably has a molecular weight of from about 1500 to about 1800 and exhibits water insolubility. Examples of compounds of this type include certain of the commercially-available PluronicTM surfactants, marketed by BASF.

Nonionic EO condensation products with propylene oxide/ethylene diamine adducts The condensation products of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylenediamine are suitable for use herein. The hydrophobic moiety of these products consists of the reaction product of ethylenediamine and excess propylene oxide, and generally has a molecular weight of from about 2500 to about 3000. Examples of this type of nonionic surfactant include certain of the commercially available TetronicTM compounds, marketed by BASF.

Nonionic alkylpolvsaccharide surfactant Suitable alkylpolysaccharides for use herein are disclosed in U.S. Patent 4,565,647, Llenado, issued January 21, 1986, having a hydrophobic group containing from about 6 to about 30 carbon atoms, preferably from about 10 to about 16 carbon atoms and a polysaccharide, e.g., a polyglycoside, hydrophilic group containing from about 1.3 to about 10, preferably from about 1.3 to about 3, most preferably from about 1.3 to about 2.7 saccharide units.Any reducing saccharide containing 5 or 6 carbon atoms can be used, e.g., glucose, galactose and galactosyl moieties can be substituted for the glucosyl moieties. (Optionally the hydrophobic group is attached at the 2-, 3-, 4-, etc. positions thus giving a glucose or galactose as opposed to a glucoside or galactoside.) The intersaccharide bonds can be, e.g., between the one position ofthe additional saccharide units and the 2-, 3-, 4-, and/or 6- positions on the preceding saccharide units.

The preferred alkylpolyglycosides have the formula R2O(CHO)t(glycosyl) wherein R2 is selected from the group consisting of alkyl, alkylphenyl, hydroxyalkyl, hydroxyalkylphenyl, and mixtures thereof in which the alkyl groups contain from 10 to 18, preferably from 12 to 14, carbon atoms; n is 2 or 3, preferably from about 1.3 to about 3, most preferably from about 1.3 to about 2.7. The glycosyl is preferably derived from glucose.

Nonionic fattv acid amide surfactant Fatty acid amide surfactants suitable for use herein are those having the formula:

wherein R6 is an alkyl group containing from 7 to 21, preferably from 9 to 17 carbon atoms and each R7 is selected from the group consisting of hydrogen, C1-C4 alkyl, C1 C4 hydroxyalkyl, and -(C2H40)XH, where x is in the range of from 1 to 3.

Amphoteric surfactant Suitable amphoteric surfactants for use herein include the amine oxide surfactants and the alkyl amphocarboxylic acids.

A suitable example of an alkyl aphodicarboxylic acid for use herein is Miranol(TM) C2M Conc. manufactured by Miranol, Inc., Dayton, NJ.

Amine Oxide surfactant Amine oxides useful in the present invention include those compounds having the formula:

wherein R3 is selected from an alkyl, hydroxyalkyl, acylamidopropoyl and alkyl phenyl group, or mixtures thereof, containing from 8 to 26 carbon atoms, preferably 8 to 18 carbon atoms; R4 is an alkylene or hydroxyalkylene group containing from 2 to 3 carbon atoms, preferably 2 carbon atoms, or mixtures thereof; x is from 0 to 5, preferably from 0 to 3; and each R5 is an alkyl or hydyroxyalkyl group containing from 1 to 3, preferably from 1 to 2 carbon atoms, or a polyethylene oxide group containing from 1 to 3, preferable 1, ethylene oxide groups. The R5 groups can be attached to each other, e.g., through an oxygen or nitrogen atom, to form a ring structure.

These amine oxide surfactants in particular include C10-C18 alkyl dimethyl amine oxides and C8-C18 alkoxy ethyl dihydroxyethyl amine oxides. Examples of such materials include dimethyloctylamine oxide, diethyldecylamine oxide, bis-(2hydroxyethyl)dodecylamine oxide, dimethyldodecylamine oxide, dipropyltetradecylamine oxide, methylethylhexadecylamine oxide, dodecylamidopropyl dimethylamine oxide, cetyl dimethylamine oxide, stearyl dimethylamine oxide, tallow dimethylamine oxide and dimethyl-2-hydroxyoctadecylamine oxide. Preferred are C10-C18 alkyl dimethylamine oxide, and C10-18 acylamido alkyl dimethylamine oxide.

Zwitterionic surfactant Zwitterionic surfactants can also be incorporated into the detergent compositions hereof These surfactants can be broadly described as derivatives of secondary and tertiary amines, derivatives of heterocyclic secondary and tertiary amines, or derivatives of quaternary ammonium, quaternary phosphonium or tertiary sulfonium compounds.

Betaine and sultaine surfactants are exemplary zwitterionic surfactants for use herein.

Betaine surfactant The betaines useful herein are those compounds having the formula R(R')2N+R2COOwherein R is a C6-C18 hydrocarbyl group, preferably a C10-C16 alkyl group or C10-16 acylamido alkyl group, each R1 is typically C1-C3 alkyl, preferably methyl,m and R2 is a C1-Cs hydrocarbyl group, preferably a C1-C3 alkylene group, more preferably a C1-C2 alkylene group.Examples of suitable betaines include coconut acylamidopropyldimethyl betaine; hexadecyl dimethyl betaine; C12-14 acylamidopropylbetaine; Cm 14 acylamidohexyldiethyl betaine; 4[C1 4-16 acylmethylamidodiethylammonio]- 1 - carboxybutane; C1 6-18 acylamidodimethylbetaine; C1 2-16 acylamidopentanediethylbetaine; [C1 2-16 acylmethylamidodimethylbetaine. Preferred betaines are C1 2-18 dimethyl-ammonio hexanoate and the C10-18 acylamidopropane (or ethane) dimethyl (or diethyl) betaines. Complex betaine surfactants are also suitable for use herein.

Sultaine surfactant The sultaines useful herein are those compounds having the formula (R(R1)2N+R2SO3- wherein R is a C6-C1g hydrocarbyl group, preferably a C10-C16 alkyl group, more preferably a C12-C13 alkyl group, each R1 is typically C1-C3 alkyl, preferably methyl, and R2 is a C1-C6 hydrocarbyl group, preferably a C1-C3 alkylene or, preferably, hydroxyalkylene group.

Ampholytic surfactant Ampholytic surfactants can be incorporated into the detergent compositions herein.

These surfactants can be broadly described as aliphatic derivatives of secondary or tertiary amines, or aliphatic derivatives of heterocyclic secondary and tertiary amines in which the aliphatic radical can be straight chain or branched.

Cationic surfactants Cationic surfactants can also be used in the detergent compositions herein. Suitable cationic surfactants include the quaternary ammonium surfactants selected from mono C6-C16, preferably C6-C10 N-alkyl or alkenyl ammonium surfactants wherein the remaining N positions are substituted by methyl, hydroxyethyl or hydroxypropyl groups.

Low molecular weight acrylic acid containing organic polymer A preferred component ofthe detergent compositions is an organic polymer containing acrylic acid or its salts having an average molecular weight of less than 15,000, hereinafter referred to as low molecular weight acrylic acid containing polymer.

The low molecular weight acrylic acid containing polymer has an average molecular weight of less than 15,000, preferably from 500 to 12,000, more preferably from 1,500 to 10,000, most preferably from 2,500 to 9,000.

The low molecular weight acrylic acid containing organic polymer is preferably present at a level of from 0.005% to 20%, more preferably from 0.1% to 10%, most preferably from 0.2% to 5% by weight of the compositions.

The weight ratio of low molecular weight acrylic acid containing polymer to organo diphosphonate component is preferably from 50:1 to 1:5, more preferably from 20:1 to 1:1, most preferably from 15:1 to 2: 1.

The low molecular weight acrylic acid containing polymer may be either a homopolymer or a copolymer including the essential acrylic acid or acrylic acid salt monomer units. Copolymers may include essentially any suitable other monomer units including modified acrylic, fumaric, maleic, itaconic, aconitic, mesaconic, citraconic and methylenemalonic acid or their salts, maleic anhydride, acrylamide, alkylene, vinylmethyl ether, styrene and any mixtures thereof.

Preferred commercially available low molecular weight acrylic acid containing homopolymers include those sold under the tradename Sokalan PA30, PA20, PA15 and PA10 by BASF GmbH, and those sold under the tradename Acusol 45N by Rohm and Haas.

Preferred low molecular weight acrylic acid containing copolymers include those which contain as monomer units: a) from 90% to 10%, preferably from 80% to 20% by weight acrylic acid or its salts and b) from 10% to 90%, preferably from 20% to 80% by weight of a substituted acrylic monomer or its salts having the general formula -[CR2-CR1(CO O-R3)]- wherein at least one of the substituents R1, R2 or R3, preferably R1 or R2 is a 1 to 4 carbon alkyl or hydroxyalkyl group, R1 or R2 can be a hydrogen and R3 can be a hydrogen or alkali metal salt. Most preferred is a substituted acrylic monomer wherein R1 is methyl, R2 is hydrogen (i.e. a methyl acrylic acid monomer). The most preferred copolymer of this type has a molecular weight of 3500 and contains 60% to 80% by weight of acrylic acid and 40% to 20% by weight of methyl acrylic acid.

Preferred commercially available low molecular weight acrylic acid containing copolymers include those sold under the tradename Sokalan CP10 by BASF GmbH.

Other suitable polyacrylate/modified polyacrylate copolymers include those copolymers of unsaturated aliphatic carboxylic acids disclosed in U.S. Patents No.s 4,530,766, and 5,084,535 which have a molecular weight of less than 15,000 in accordance with the invention.

Additional inorganic polymeric compound Additional organic polymeric compounds may be added to the detergent compositions. By additional organic polymeric compounds it is meant essentially any polymeric organic compounds commonly used as dispersants, antiredeposition and soil suspension agents in detergent compositions, which do not fall within the definition of low molecular weight acrylic acid containing polymers given hereinbefore.

Additional organic polymeric compound may be incorporated into the detergent compositions ofthe invention at a level of from 0.05% to 30%, preferably from 0.5% to 15%, most preferably from 1% to 10% by weight ofthe compositions.

Examples of additional organic polymeric compounds include the water soluble organic homo- or co-polymeric polycarboxylic acids or their salts in which the polycarboxylic acid comprises at least two carboxyl radicals separated from each other by not more than two carbon atoms. Polymers ofthe latter type are disclosed in GB-A-1,596,756. Examples of such salts are the copolymers of polyacrylate with maleic anhydride having a molecular weight of from 20,000 to 70,000, especially about 40,000.

Other suitable additional organic polymeric compounds include the polymers of acrylamide and acrylate having a molecular weight of from 16,000 to 100,000, and the acrylate/fumarate copolymers having a molecular weight of from 16,000 to 80,000.

The polyamino compounds are useful herein including those derived from aspartic acid such as those disclosed in EP-A-305282, EP-A-305283 and EP-A-351629.

Other additional organic polymeric compounds suitable for incorporation in the detergent compositions herein include cellulose derivatives such as methylcellulose, carboxymethylcellulose and hydroxyethylcellulose.

Further useful additional organic polymeric compounds are the polyethylene glycols, particularly those of molecular weight 1000-10000, more particularly 2000 to 8000 and most preferably about 4000.

Lime soap dispersant compound The compositions of the invention may contain a lime soap dispersant compound, which has a lime soap dispersing power (LSDP), as defined hereinafter of no more than 8, preferably no more than 7, most preferably no more than 6. The lime soap dispersant compound is preferably present at a level of from 0.1% to 40% by weight, more preferably 1% to 20% by weight, most preferably from 2% to 10% by weight of the compositions.

A lime soap dispersant is a material that prevents the precipitation of alkali metal, ammonium or amine salts of fatty acids by calcium or magnesium ions. A numerical measure of the effectiveness of a lime soap dispersant is given by the lime soap dispersing power (LSDP) which is determined using the lime soap dispersion test as described in an article by H.C. Borghetty and C.A. Bergman, J. Am. Oil. Chem. Soc., volume 27, pages 88-90, (1950). This lime soap dispersion test method is widely used by practitioners in this art field being referred to , for example, in the following review articles; W.N. Linfield, Surfactant Science Series, Volume 7, p3; W.N. Linfield, Tenside Surf. Det., Volume 27, pagesl59-161, (1990); and M.K. Nagarajan, W.F. Masler, Cosmetics and Toiletries, Volume 104, pages 71-73, (1989).The LSDP is the % weight ratio of dispersing agent to sodium oleate required to disperse the lime soap deposits formed by 0.025g of sodium oleate in 30ml of water of 333ppm CaCO3 (Ca:Mg=3:2) equivalent hardness.

Polymeric lime soap dispersants suitable for use herein are described in the article by M.K. Nagarajan and W.F. Masler, to be found in Cosmetics and Toiletries, Volume 104, pages 71-73, (1989). Examples of such polymeric lime soap dispersants include certain water-soluble salts of copolymers of acrylic acid, methacrylic acid or mixtures thereof and an acrylamide or substituted acrylamide, where such polymers typically have a molecular weight of from 5,000 to 20,000.

Surfactants having good lime soap dispersant capability will include certain amine oxides, betaines, sulfobetaines, alkyl ethoxysulfates and ethoxylated alcohols.

Exemplary surfactants having a LSDP of no more than 8 for use in accord with the invention include C16-Cl8 dimethyl amine oxide, C12-Clg alkyl ethoxysulfates with an average degree of ethoxylation of from 1-5, particularly C12-C15 alkyl ethoxysulfate surfactant with a degree of ethoxylation of about 3 (LSDP=4), and the C13-C15 ethoxylated alcohols with an average degree of ethoxylation of either 12 (LSDP=6) or 30, sold under the trade names Lutensol A012 and Lutensol A030 respectively, by BASF GmbH.

Bleaching agents The detergent compositions ofthe invention may include bleaching agent selected from chlorine bleaches, inorganic perhydrate salts, peroxyacid bleach precursors and organic peryoxacids.

In a particularly preferred embodiment of the invention, there is provided a means of delaying the release of oxygen bleach into the wash solution. Said means may be provided, for example by coating a granular bleach component with a hydrophobic coating, or by choice of physical form of the bleach which has a slow rate of dissolution by virtue, for example of its density or particle size.

Delayed release of bleach into the wash solution can be advantageous in the prevention of tarnishing of silverware in washload, particularly when a component designed to protectively coat the silver in the wash is also included in the formulation. Such silver tarnish prevention technologies are disclosed in the Applicant's co-pending European Applications Nos. 9370004.4, 93870090.3, 93201918.5 and 93202095.1.

Chlorine bleaching agents Chlorine bleaches include the alkali metal hypochlorites and chlorinated cyanuric acid salts. The use of chlorine bleaches in the composition of the invention is preferably minimized, and more preferably the compositions contain no chlorine bleach.

Inorganic perhydrate bleaching agents The detergent compositions in accord with the invention preferably include an inorganic perhydrate salt, normally in the form of the sodium salt preferably at a level of from 1% to 40% by weight, more preferably from 2% to 30% by weight and most preferably from 5% to 25% by weight of the compositions.

Examples of inorganic perhydrate salts include perborate, percarbonate, perphosphate, persulfate and persilicate salts. The inorganic perhydrate salts are normally the alkali metal salts. The inorganic perhydrate salt may be included as the crystalline solid without additional protection. For certain perhydrate salts however, the preferred executions of such granular compositions utilize a coated form of the material which provides better storage stability for the perhydrate salt in the granular product.

Sodium perborate can be in the form of the monohydrate of nominal formula NaBO2H202 or the tetrahydrate NaBO2H202.3H2O.

Sodium percarbonate, which is a preferred perhydrate for inclusion in detergent compositions in accordance with the invention, is an addition compound having a formula corresponding to 2Na2CO3.3H202, and is available commercially as a crystalline solid. The percarbonate is most preferably incorporated into such compositions in coated form. The most preferred coating material comprises mixed salt of an alkali metal sulphate and carbonate. Such coatings together with coating processes have previously been described in GB-1,466,799, granted to Interox on 9th March 1977.

The weight ratio of the mixed salt coating material to percarbonate lies in the range from 1: 200 to 1: 4, more preferably from 1: 99 to 1: 9, and most preferably from 1: 49 to 1:19. Preferably, the mixed salt is of sodium sulphate and sodium carbonate which has the general formula Na2SO4.n.Na2CO3 wherein n is form 0.1 to 3, preferably n is from 0.15 to 1.0 and most preferably n is from 0.2 to 0.5.

Another suitable coating material is sodium silicate of SiO2 : Na2O ratio from 1.6:1 to 3.4:1, preferably 2.8:1, applied as an aqueous solution to give a level of from 2% to 10%, (normally from 3% to 5%) of silicate solids by weight of the percarbonate.

Magnesium silicate can also be included in the coating. Other suitable coating materials include the alkali and alkaline earth metal sulphates and carbonates.

Potassium peroxymonopersulfate is another inorganic perhydrate salt of usefulness in the detergent compositions.

Peroxvacid bleach precursors The detergent compositions in accord with the present invention also preferably include a peroxyacid bleach precursor (bleach activator), usually in combination with an inorganic perhydrate salt. Peroxyacid bleach precursors are normally incorporated at a level of from 1% to 20% by weight, more preferably from 1% to 10% by weight, most preferably from 1% to 7% by weight ofthe compositions.

Peroxyacid bleach precursors for inclusion in the machine dishwashing detergent compositions in accordance with the invention typically contain one or more N- or O- acyl groups, which precursors can be selected from a wide range of classes. Suitable classes include anhydrides, esters, imides and acylated derivatives of imidazoles and oximes, and examples of useful materials within these classes are disclosed in GB-A1586789. The most preferred classes are esters such as are disclosed in GB-A-836988, 864798, 1147871 and 2143231 and imides such as are disclosed in GB-A-855735 & BR< 1246338.

Particularly preferred bleach precursor compounds are the N,N,N1,N1 tetra acetylated compounds of formula (CH3CO)2-(CH2)X-(CH3CO)2 wherein x can be O or an integer between 1 & 6.

Examples include tetra acetyl methylene diamine (TAMD) in which x=l, tetra acetyl ethylene diamine (TAED) in which x=2 and tetraacetyl hexylene diamine (TAHD) in which x=6. These and analogous compounds are described in GB-A-907356. The most preferred peroxyacid bleach precursor is TAED.

Another preferred class of peroxyacid bleach activator compounds are the amide substituted compounds described in EP-A-0170386.

Other peroxyacid bleach precursor compounds include sodium nonanoyloxy benzene sulfonate, sodium trimethyl hexanoyloxy benzene sulfonate and sodium acetoxy benzene sulfonate.

Organic peroxyacids The detergent compositions may also contain organic peroxyacids at a level of from 1% to 15% by weight, more preferably from 1% to 10% by weight ofthe composition.

Useful organic peroxyacids include the amide substituted peroxyacids described in EP-A0170386.

Other organic peroxyacids include diperoxy dodecanedioc acid, diperoxy tetra decanedioc acid, diperoxyhexadecanedioc acid, mono- and diperazelaic acid, mono- and diperbrassylic acid, monoperoxy phthalic acid, perbenzoic acid, and their salts as disclosed in, for example, EP-A-0341 947.

Heavy metal ion sequestrants Heavy metal ion sequestrants are useful components herein. By heavy metal ion sequestrants it is meant components which act to sequester (chelate) heavy metal ions. These components may also have calcium and magnesium chelation capacity, but preferentially they bind heavy metal ions such as iron, manganese and copper.

Heavy metal ion sequestrants are preferably present at a level of from 0.005% to 20%, more preferably from 0.05% to 10%, most preferably from 0.1% to 5% by weight of the compositions.

Heavy metal ion sequestrants, which are acidic in nature, having for example phosphonic acid or carboxylic acid tunctionalities, may be present either in their acid form or as a complex/salt with a suitable counter cation such as an alkali or alkaline metal ion, ammonium, or substituted ammonium ion, or any mixtures thereof. Preferably any salts/complexes are water soluble. The molar ratio of said counter cation to the heavy metal ion sequestrant is preferably at least 1:1.

Suitable heavy metal ion sequestrants for use herein include the organo aminophosphonates, such as the amino alkylene poly (alkylene phosphonates) and nitrilo trimethylene phosphonates. Preferred organo aminophosphonates are diethylene triamine penta (methylene phosphonate) and hexamethylene diamine tetra (methylene phosphonate).

Other suitable heavy metal ion sequestrants for use herein include nitrilotriacetic acid and polyaminocarboxylic acids such as ethylenediaminotetracetic acid, ethylenetriamine pentacetic acid, or ethylenediamine disuccinic acid. Especially preferred is ethylenediamine-N,N'-disuccinic acid (EDDS), most preferably present in the form of its S,S isomer, which is preferred for its biodegradability profile.

Still other suitable heavy metal ion sequestrants for use herein are iminodiacetic acid derivatives such as 2-hydroxyethyl diacetic acid or glyceryl imino diacetic acid, described in EPA 317 542 and EPA 399 133.

In one preferred aspect of the invention any heavy metal ion sequestrant, particularly where said sequestrant comprises organo aminophosphonate components, is sprayed onto powdered sodium sulphate prior to incorporation into granular compostions in accord with the invention. This step leads to enhanced sequestrant stability in the granular detergent matrix.

Enzyme Another optional ingredient useful in the detergent compositions of the invention is one or more enzymes.

Preferred enzymatic materials include the commercially available lipases, amylases, neutral and alkaline proteases, esterases, cellulases and peroxidases conventionally incorporated into detergent compositions. Suitable enzymes are discussed in US Patents 3,519,570 and 3,533,139.

Preferred commercially available protease enzymes include those sold under the tradenames Alcalase, Savinase, Durazym, and Esperase by Novo Industries A/S (Denmark), those sold under the tradename Maxatase, Maxacal and Maxapem by Gist Brocades, those sold under the tradename FN, FNA and FN-2 by Genencor International, and those sold under the tradename Opticlean and Optimase by Solvay Enzymes. Protease enzyme may be incorporated into the compositions in accordance with the invention at a level of from 0.0001% to 2% active enzyme by weight of the composition.

Preferred amylases include, for example, & amylases obtained from a special strain of B licheniforms, described in more detail in GB-1,269,839 (Novo). Preferred commercially available amylases include for example, those sold under the tradename Rapidase by Gist-Brocades, and those sold under the tradename Termamyl and BAN by Novo Industries A/S. Amylase enzyme may be incorporated into the composition in accordance with the invention at a level of from 0.0001% to 2% active enzyme by weight of the composition.

Lipolytic enzyme (lipase) may be present at levels of active lipolytic enzyme of from 0.0001% to 2% by weight, preferably 0.001% to 1% by weight, most preferably from 0.001% to 0.5% by weight ofthe compositions.

The lipase may be fungal or bacterial in origin being obtained, for example, from a lipase producing strain of Humicola sp.or Thermomwes sp. or Pseudomonas pseudoalcaligenes or Pseudomas fluorescens. Lipase from chemically or genetically modified mutants of these strains are also useful herein.

A preferred lipase is derived from Pseudomonas pseudoalcaligenes, which is described in Granted European Patent, EP-B-0218272.

Another preferred lipase herein is obtained by cloning the gene from Humicola lanuginosa and expressing the gene in Aspergillus oryza, as host, as described in European Patent Application, EP-A-0258 068, which is commercially available from Novo Industri A/S, Bagsvaerd, Denmark, under the trade name Lipolase. This lipase is also described in U.S. Patent 4,810,414, Huge-Jensen et al, issued March 7, 1989.

Enzyme Stabilizing Svstem Enzyme-containing compositions herein may comprise from 0.001% to 10%, preferably from 0.005% to 8%,most preferably from 0.01% to 6%, by weight of an enzyme stabilizing system. The enzyme stabilizing system can be any stabilizing system which is compatible with the detersive enzyme. Such stabilizing systems can comprise calcium ion, boric acid, propylene glycol, short chain carboxylic acid, boronic acid, and mixtures thereof. Such stabilizing systems can also comprise reversible protease inhibitors.

The compositions herein may further comprise from 0% to 10%, preferably from 0.01% to 6% by weight, of chlorine bleach scavengers, added to prevent chlorine bleach species present in many water supplies from attacking and inactivating the enzymes, especially under alkaline conditions. While chlorine levels in water may be small, typically in the range from 0.5 ppm to 1.75 ppm, the available chlorine in the total volume of water that comes in contact with the enzyme during washing is usually large; accordingly, enzyme stability in-use can be problematic.

Suitable chlorine scavenger anions are widely available, and are illustrated by salts containing ammonium cations or sulfite, bisulfite, thiosulfite, thiosulfate, iodide, etc.

Antioxidants such as carbamate, ascorbate, etc., organic amines such as ethylenediaminetetracetic acid (EDTA) or alkali metal salt thereof, monoethanolamine (MEA), and mixtures thereof can likewise be used. Other conventional scavengers such as bisulfate, nitrate, chloride, sources of hydrogen peroxide such as sodium perborate tetrahydrate, sodium perborate monohydrate and sodium percarbonate, as well as phosphate, condensed phosphate, acetate, benzoate, citrate, formate, lactate, malate, tartrate, salicylate, etc. and mixtures thereof can be used if desired.

Corrosion inhibitor The present compositions may also contain corrosion inhibitor which is preferably incorporated at a level of from 0.05% to 10%, preferably from 0.1% to 5% by weight of the total composition.

Suitable corrosion inhibitors include paraffin oil typically a predominantly branched aliphatic hydrocarbon having a number of carbon atoms in the range of from 20 to 50; preferred paraffin oil selected from predominantly branched C25-45 species with a ratio of cyclic to noncyclic hydrocarbons of about 32:68; a paraffin oil meeting these characteristics is sold by Wintershall, Salzbergen, Germany, under the trade name WINOG 70.

Other suitable corrosion inhibitor compounds include benzotriazole and any derivatives thereof, mercaptans and diols, especially mercaptans with 4 to 20 carbon atoms including lauryl mercaptan, thiophenol, thionapthol, thionalide and thioanthranol. Also suitable are the C12-C20 fatty acids, or their salts, especially aluminium tristearate. The C12-C20 hydroxy fatty acids, or their salts, are also suitable. Phosphonated octa-decane and other anti-oxidants such as betahydroxytoluene (BHT) are also suitable.

Suds suppressing svstem The compositions of the invention may comprise a suds suppressing system preferably present at a level of from 0.01% to 15%, more preferably from 0.05% to 10%, most preferably from 0.1% to 5% by weight ofthe composition.

Suitable suds suppressing systems for use herein may comprise essentially any known antifoam compound, including, for example silicone antifoam compounds, 2-alkyl alcanol antifoam compounds, and paraffin antifoam compounds.

By antifoam compound it is meant herein any compound or mixtures of compounds which act such as to depress the foaming or sudsing produced by a solution of a detergent composition, particularly in the presence of agitation of that solution.

Particularly preferred antifoam compounds for use herein are silicone antifoam compounds defined herein as any antifoam compound including a silicone component.

Such silicone antifoam compounds also typically contain a silica component. The term "silicone" as used herein, and in general throughout the industry, encompasses a variety of relatively high molecular weight polymers containing siloxane units and hydrocarbyl group of various types.

Other suitable antifoam compounds include the monocarboxylic fatty acids and soluble salts thereof. These materials are described in US Patent 2,954,347, issued September 27, 1960 to Wayne St. John. The monocarboxylic fatty acids, and salts thereof, for use as suds suppressor typically have hydrocarbyl chains of 10 to about 24 carbon atoms, preferably 12 to 18 carbon atoms. Suitable salts include the alkali metal salts such as sodium, potassium, and lithium salts, and ammonium and alkanolammonium salts.

Other suitable antifoam compounds include, for example, high molecular weight hydrocarbons such as paraffin, fatty esters (e.g. fatty acid triglycerides), fatty acid esters of monovalent alcohols, aliphatic C18-C40 ketones (e.g. stearone) N-alkylated amino triazines such as tri- to hexa-alkylmelamines or di- to tetra alkyldiamine chlortriazines formed as products of cyanuric chloride with two or three moles of a primary or secondary amine containing 1 to 24 carbon atoms, propylene oxide, bis stearic acid amide and monostearyl di-alkali metal (e.g. sodium, potassium, lithium) phosphates and phosphate esters. The hydrocarbons, such as paraffin and haloparaffin, can be utilized in liquid form.The liquid hydrocarbons will be liquid at room temperature and atmospheric pressure, and will have a pour point in the range of about -40 C and about 5"C, and a minimum boiling point not less than 1 100C (atmospheric pressure). It is also known to utilize waxy hydrocarbons, preferably having a melting point below about 100"C.

Hydrocarbon suds suppressors are described, for example, in U.S. Patent 4,265,779, issued May 5, 1981 to Gandolfo et al. The hydrocarbons, thus, include aliphatic, alicyclic, aromatic, and heterocyclic saturated or unsaturated hydrocarbons having from about 12 to about 70 carbon atoms.

Copolymers of ethylene oxide and propylene oxide, particularly the mixed ethoxylated/propoxylated fatty alcohols with an alkyl chain length of from 10 to 16 carbon atoms, a degree of ethoxylation of from 3 to 30 and a degree of propoxylation of from 1 to 10, are also suitable antifoam compounds for use herein.

Suitable 2-alky-alcanols antifoam compounds for use herein have been described in DE 40 21 265. The 2-alkyl-alcanols suitable for use herein consist of a C6 to C16 alkyl chain carrying a terminal hydroxy group, and said alkyl chain is substituted in the alpha position by a C1 to C10 alkyl chain. Mixtures of 2-alkyl-alcanols can be used in the compositions according to the present invention.

Solvent The compositions of the invention may contain organic solvents, particularly when formulated as liquids or gels. The compositions in accord with the invention preferably contain a solvent system present at levels of from 1% to 30% by weight, preferably from 3% to 25% by weight, more preferably form 5% to 20% by weight of the composition.

The solvent system may be a mono, or mixed solvent system. Preferably, at least the major component of the solvent system is of low volatility.

Suitable organic solvent for use herein has the general formula RO(CH2C(Me)HO)nH, wherein R is an alkyl, alkenyl, or alkyl aryl group having from 1 to 8 carbon atoms, and n is an integer from 1 to 4. Preferably, R is an alkyl group containing 1 to 4 carbon atoms, and n is 1 or 2. Especially preferred R groups are nbutyl or isobutyl. Preferred solvents of this type are 1-n-butoxypropane-2-ol (n=1); and 1(2-n-butoxy-1-methylethoxy)propane-2-ol (n=2), and mixtures thereof.

Other solvents useful herein include the water soluble CARBITOL solvents or watersoluble CELLOSOLVE solvents. Water-soluble CARBITOL solvents are compounds of the 2-(2-alkoxyethoxy)ethanol class wherein the alkoxy group is derived from ethyl, propyl or butyl; a preferred water-soluble carbitol is 2-(2-butoxyethoxy)ethanol also known as butyl carbitol. Water-soluble CELLOSOLVE solvents are compounds of the 2-alkoxyethoxy ethanol class, with 2-butoxyethoxyethanol being preffered.

Other suitable solvents are benzyl alcohol, and diols such as 2-ethyl-1,3-hexanediol and 2,2,4-trimethl- 1,3-pentanediol.

The low molecular weight, water-soluble, liquid polyethylene glycols are also suitable solvents for use herein.

The alkane mono and diols, especially the C1-C6 alkane mono and diols are suitable for use herein. C1-C4 monohydric alcohols (eg: ethanol, propanol, isopropanol, butanol and mixtures thereof) are preferred, with ethanol particularly preferred. The C1-C4 dihydric alcohols, including propylene glycol, are also preferred.

Hvdrotropes Hydrotrope may be added to the compositions, and is typically present at levels of from 0.5% to 20%, preferably from 1% to 10%, by weight.

Useful hydrotropes include sodium, potassium, and ammonium xylene sulfonates, sodium, potassium, and ammonium toluene sulfonate, sodium potassium and ammonium cumene sulfonate, and mixtures thereof.

EXAMPLES The following examples illustrate the present invention.

In the following compositions, the abbreviated identifications have the following meanings: Citrate Trisodium citrate dihydrate Phosphate Sodium tripolyphosphate Nonionic C13-C15 mixed ethoxylated/propoxylated fatty alcohol with an average degree of ethoxylation of 3.8 and an average degree of propoxylation of 4.5 sold under the tradename Plurafac LF404 by BASF Gmbh HEDP Ethane 1-hydroxy-1, 1-diphosphonic acid DETMP Diethylene triamine penta (methylene phosphonic acid), marketed by Monsanto under the tradename Dequest 2060 EDDS Ethylenediamine-N,N'-disuccinic acid MA/AA Copolymers of 1:4 maleic/acrylic acid, average molecular weight about 80,000 AA/MA Random copolymers of acrylic acid and methacrylic cid in a weight ratio of approximately 30:70, with a molecular weight of about 3,500.

Polyacrylate A polyacrylate homopolymer with an average molecular weight of 8,000 sold under the tradename PA30 by BASF GmbH SCS Sodium cumene sulfonate Lipase Lipolytic enzyme sold under the tradename lipolase by Novo Industries A/S Protease Proteolytic enzyme sold under the trade name Savinase by Novo Industries A/S Amylase Amylolytic enzyme sold under the tradename Termamyl by Novo Industries A/S Silicate Sodium silicate (2.0 ratio) - present at distinct particulate component Metasilicate Sodium metasilicate Carbonate Sodium carbonate PB4 Sodium percarbonate monohydrate PUB 1 Sodium percarbonate monohydrate PC Sodium percarbonate coated with a mixed salt of formula Na2SO4.n.Na2CO3 where n is 0.3, and the coating level is 2.5% by weight.

TAED Tetraacetylethylenediamine AVC1 Chlorine bleach (expressed as available chlorine) Paraffin Paraffin oil, sold under the tradename Winog 70 by Wintershall EXAMPLE 1 The following base compositions containing alkali silicate as a distinct particulate component were prepared.

A B C D E Citrate 33.0 33.0 33.0 33.0 33.0 Silicate 25.7 25.7 25.7 25.7 25.7 PUB 1 1.9 1.9 1.9 PB4 8.7 8.7 8.7 - PC - - 10.4 10.4 TAED 4.4 4.4 4.4 4.4 4.4 Protease 2.2 2.2 2.2 2.2 2.2 Lipase 1.5 - Amylase 1.5 1.5 1.5 1.5 1.5 Benzotriazole 0.3 0.3 0.3 0.3 0.3 Paraffin 0.5 0.5 0.5 0.5 0.5 Nonionic 1.5 1.5 1.5 1.5 1.5 EDDS 0.2 Polyacrylate 3.7 3.7 - 3.7 AA/MA 3.7 - - 3.7 Misc/moisture 10.7 10.7 10.7 10.7 10.7 to balance pH (1% 10.7 10.7 10.7 10.7 10.7 solution) Inert carrier particles were prepared by spraying a 60% solution of HEDP having a pH as a 1% solution in water of 1.5 onto particles of sodium carbonate such that the weight ratio of carbonate to HEDP was 14:1. The particles were subsequently dried and then added by dry mixing to each of the base compositions A to E at a level of 7.5% by weight ofthe compositions (i.e. 7% carbonate, 0.5% HEDP by weight), in accord with the invention.

EXAMPLE 2 Inert carrier particles were prepared by spraying a 60% solution of HEDP having a pH as a 1% solution in water of 1.5 onto particles of sodium sulphate such that the weight ratio of sulphate to HEDP was 14:1. The particles were subsequently dried and then added by dry mixing to each of the base compositions A to E at a level of 7.5% by weight of the compositions (i.e. 7% sulphate, 0.5% HEDP by weight), in accord with the invention.

Claims (1)

1. A process for making a particulate detergent composition comprising the steps of: (a) the application of an acidic solution of an organo diphosphonate to alkali metal silicate free inert carrier particles comprising a solid salt, by spraying of said acidic solution onto said inert carrier particles; and (b) admixing the particles formed in step (a) with particles containing an alkali metal silicate.