GB2332446A - Detergent composition comprising a dianionic surfactant - Google Patents

Abstract

The present invention relates to a detergent composition comprising a surfactant system wherein the surfactant system comprises a net zero charge surfactant and a dianionic surfactant. The net zero charge surfactant may be non-ionic, zwitterionic or a stoichiometric combination of cationic and anionic surfactants. Preferred components include betaines. Preferred dianionics include alkyl disulphates and α-sulphocarboxylate compounds.

Description

2332446 Detergtnt CoMposition

Technical Field

The present invention relates to a detergent composition comprising a surfactant system comprising a net zero charge surfactant and a dianionic surfactant.

Backgroun Most conventional detergent compositions contain at least one detersive surfactant.

More commonly, detergent compositions contain a mixture of various detersive surfactants including nonionic. anionic and cationic surfactants.

Surfactants have found use as detergent components capable of removing a wide variety of soils and stains. It has been found that nonionic surfactants are particularly useful in removing greasy or oily soils. However, it has also been found that detergent compositions that contain surfactant systems comprised exclusively of nonionic surfactants do not adequately maintain the perceived whiteness of the fabric being washed. This poor fabric whiteness maintenance is not acceptable to the consumer.

2 In the past, the Applicant has found that by formulating a detergent composition comprising a surfactant system comprising both nonionic and anionic surfactants, the detergent composition fabric whiteness maintenance can be improved. However the Applicant has subsequently found that the greasy-oily soil removal benefits provided 5 by the nomonic surfactant are adversely affected by the presence of the anionic surfactant in the surfactant system.

It is an object of the present invention to provide a detergent composition comprising a surfactant system that provides both greasy/oily soil removal and fabric whiteness 10 maintenance.

1 z, Summ@a of Invention According to the present invention there is provided a detergent composition comprising a surfactant system comprising a net zero charge (NZC) surfactant and a dianionic surfactant wherein the dianionic surfactant comprises a terminally located anionic group and wherein the equivalent weight of the dianionic surfactant salt is less than 200.

Detailed Description of the Invention

The detergent composition of the present invention comprises a surfactant system which comprises a net zero charge (NZC) surfactant and a dianionic surfactant. The weight ratio of NW surfactant to dianionic surfactant is 1: 1 to 10: 1, preferably 2:1 to 9:1.

In an alternative embodiment of the present invention the surfactant system additionally comprises an anionic or catioruc surfactant at a level of preferably less than 15%, more preferably less than 10%, most preferably less than 5% by weight of 3 the surfactant system. The additional surfactant can be selected ftom any of the anionic or cationic surfactants described below.

Net Zero Charee Surfactant The detergent compositions of the invention contain a net zero charge (NZC) surfactant. The NW surfactant can be selected from nonionic, amphoteric, zvvitterionic surfactants or a mixture of cationic and anionic surfactants at a 1: 1 charge ratio or mixtures of the above.

The NW surfactant is present as a component of a surfactant system at a level of from 50% to 99%, more preferably from 60% to 95% by weight, most preferably from 70% to 90% by weight of the surfactant system.

A ty ical listing of nonionic, amphoteric, zwitterionic and anionic classes, and pi species of these surfactants, is given in U.S.P. 3,929,678 issued to Laughlin and HeUnng on December '30, 1975. Further examples are given in "Surface Active Agents and Detergents" (Vol. I and 11 by Schwartz, Perry and Berch). A list of suitable cationic surfactants is given in U.S.P. 4, 259,217 issued to Murphy on March 31. 1981.

Alkoxylated nonionic surfactant Alkoxylated nonionic surfactants are highly preferred NW surfactants for use herein. The ethoxylated and propoxylated nonionic surfactants are preferred.

Preferred alkoxylated surfactants can be selected from the classes of the nonionic condensates of al-kyl phenols, nonionic ethoxylated alcohols, nonionic ethoxylated and/or propoxylated fatty alcohols, nonionic ethoxylate and/or propoxylate condensates with propylene glycol, and the nonionic ethoxylate condensation products With propylene oxide and/or ethylene diamine adducts.

4 Especially preferred alkoxylated nonionic surfactants include the condensation products of aliphatic alcohols with from I to 25 moles of alkylene oxide, particularly ethylene oxide and/or propylene 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 2 to 10 moles of ethylene oxide per mole of alcohol.

Nonionic p2Ivhydroxy fatty acid amide surfactant Polyhydroxy fatty acid amides suitable for use herein are those having the structural formula R2CONR I Z wherein: R I is H, C I -C4 hydrocarbyl, 2-hydroxy ethyl, 2hydroxy propyl, ethoxy, propoxy, or a mixture thereof, preferably C I -C4 alkyl, more preferably C I or C2 alkyl, most preferably C I alkyl (i.e., methyl). and R-) Is a C5C31 hydrocarbyl, preferably straight-chain C5-C 19 alkyl or alkenyl, more preferably strai ght-chain C9-C 17 alkyl or alkenyl. most preferably straight-chain C I I -C 17 alk,,,l 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 20 preferably Z is a glycityl.

Nonionic fatty acid amide surfactant Suitable fatty acid amide surfactants include those having the formula:

R6CON(R7)2 wherein R6 is an alkyl group containing from 7 to 2 1, preferably from 9 to 17 carbon atoms and each R7 is selected from the group consisting of hydrogen. C 1 -C4 alkyl, C 1 -C4 hydroxyalkyl, and (C21---140)xH, where x is in the range of from 1 to 3.

Nonionic g&1p2Iysaccharide 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 6 to 30 carbon atoms and a polysaccharide, e.g., a polyglycoside, hydrophilic group 5 containing from 1. 3 to 10 saccharide units.

Preferred alkylpolyglycosides have the formula:

R2O(CriH2riOXglYcOsY1)x 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 carbon atoms; n is 2 or 3; t is from 0 to 10, and x is from 1.3 to 8. 'Re glycosyl is preferably derived from glucose.

End-capped nonionic surfactants End-capped nonionic surfactants include essentially any nonionic surfactant comprising a branched chain alkyl or substituted alkyl group. Suitable end-capped CI I nonionics include end-capped Butyl-polypropylene glycol ethyl ether described in GB 1,221,217 and end-capped polyethylene glycol ether describes in US 5.2051.9-59.

Preferred end-capped nonionic surfactants include the alkoxviated and alkoxylated alcohol nonionic end-capped surfactants.

Amphoteric surfactant Suitable amphoteric surfactants for use herein include the amine oxide surfactants 25 and the alkyl amphocarboxylic acids.

Suitable amine oxides include those compounds having the formula -1 R3(OR4)xNO(R5)2 wherein R3 is selected from an alkvl. hydroxvalkyl, 6 acylamidopropoyl and alkyl phenyl group, or mixtures thereof, containing from 8 to 26 carbon atoms; R4 is an alkylene or hydroxyalkylene group containing from 2 to 3 carbon atoms, or mixtures thereof; x is from 0 to 5, preferably from 0 to 3; and each R5 is an alkyl or hydroxyalkyl group containing from I to 3, or a polyethylene oxide 5 group containing from I to 3 ethylene oxide groups. Preferred are C I O-C 18 alkyl dimethylamine oxide, and C 10- 18 acylamido alkyl dimethylamine oxide.

A suitable example of an alkyl aphodicarboxylic acid is MiranolTm C2M Conc. manufactured by Miranol, Inc., Dayton, NJ.

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 phosphonlurn or tertiary sulf6murn compounds. Betaine and sultaine surfactants are exemplary zwitterioruic surfactants for use herein.

Suitable betaines are those compounds having the formula R(W).)NR2C00wherein R is a C6-C 18 hydrocarbyll group, each RI is typically C 1 -C-3 alkyL and R2 is a Cl -C5 hydrocarbyl group. Preferred betaines are C 12-18 dimethyl- ammonio hexanoate and the C 10- 18 acylamidopropane (or ethane) dimethyl (or diethyl) betaines. Complex betame surfactants are also suitable for use herein.

Anionic surfactarit Essentially any anionic surfactants useful for detersive purposes are suitable for use herein either in combination with a cationic surfactant as a NZC surfactant or when present in less than 15% by weight of the surfactant system. Where an anioruic surfactant is present as a component of the NZC surfactant, it is essential that a cationic surfactant is also present. The anionic and cationic surfactants are present at 7 levels to achieve a 1: 1 charge ratio, such that the net charge of the surfactant mixture is zero. The anionic and cationic surfactants can be added to the detergent composition separately or can be pre-mixed to form a NW surfactant and then added to the detergent composition.

Suitable anionic surfactants; can include salts (including, for example, sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts) of the anionic sulfate, sulfanate, carboxylate and sarcosinate surfactants. Anionic sulfate surfactants are preferred.

Other anionic surfactants include the isethionates such as the acyl isethionates. Nacyl taurates, fatty acid amides of methyl tauride, alkyl succinates and sulfosuccinates, monoesters of sulfosuccinate (especially saturated and unsaturated c 12-CIS monoesters) diesters of sulfosuccinate (especial-ly saturated and unsaturated c 6-C 14 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 pnmary and secondary alkyl sulfates, alkyl ethoxysulfates. fatty oleoyl glycerol sulfates, alkyl phenol ethylene oxide ether sulfates, the C5-C 17 acyl-N-(C I -C4 alkyl) and -N-(C I -C2 hydroxyalkyl) glucamine sulfates, and sulfates of alkyipolysaccharides such as the sulfates of alkylpolyglucoside (the nonionic nonsulfated compounds being described herein).

Alkyl sulfate surfactants are preferably selected from the linear and branched primary C I O-C 18 alkyl sulfates, more preferably the C I I -C 15 branched chain alkyl sulfates and the C I 2-C 14 linear chain alkyl sulfates.

8 Alkyl ethoxysulfate surfactants; are preferably selected from the group consisting of the C I O-C 18 alkyl sulfates which have been ethoxylated with from 0. 5 to 20 moles of ethylene oxide per molecule. More preferably, the alkyl ethoxysulfate surfactant is a C I I -C 18, most preferably C I I -C 15 alkyl sulfate which has been ethoxylated with 5 from 0.5 to 7, preferably from I to 5, moles of ethylene oxide per molecule.

A particularly preferred aspect of the invention employs mixtures of the preferred alkyl sulfate and alkyl ethoxysulfate surfactants. Such mixtures have been disclosed in PCT Patent Application No. WO 93/18124.

Anionic sulfonate surfactant Anionic sulfonate surfactants suitable for use herein include the salts Of C5-C20 linear alkylbenzene sulfonates, alkyl ester sulfonates, C6-C22 primary or secondary alkane sulfonates, C6C224 olefin sulfonates. sulfonated polycarboxylic acids, alkyl glycerol sulfonates. fatty acyl glycerol sulfonates, fatty oleyl glycerol sulfonates, and any mixtures thereof Anionic carboxylate surfactant Suitable anionic carboxylate surfactants include the alkyl ethoxy carboxylates, the alkyl polvethoxy polycarboxylate surfactants and the soaps ('alkyl carboxvls'), especially certain secondary soaps as described herein.

Suitable alkyl ethoxy carboxylates include those with the formula RO(CH. )CH-W)x CH.)C00-M+ wherein R is a C6 to Cl 8 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 20 % and M is a cation. Suitable alkyl polyethoxy polycarboxylate surfactants include those having the formula RO-(CHR I -CHR2-0)-R3 wherein R is a C6 to Cl 8 alb-1 group, x is from 1 to 25, R 1 and R.) are selected from the group consistina of hydrogen. methyl acid radicg succinic acid radical, hydroxysuccinic 9 acid radical, and mixtures thereof, and R3 is selected from the group consisting of hydrogen, substituted or unsubstituted hydrocarbon having between 1 and 8 carbon atoms, and mixtures thereof Suitable soap surfactants include the secondary soap surfactants which contain a carboxyl unit connected to a secondary carbon. 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-l-octanoic acid and 2-pentyl-l-heptanoic acid. Certain soaps may also be included as suds suppressors.

Alkali metal sarcosinate surfactant Other suitable anionic surfactants are the alkali metal sarcosinates of formula R-CON (R 1) CH.) COOM. wherein R is a C5-C 17 linear or branched alkyl or alkenyl garoup, R 1 is a C 1 -C4 alkyl group and M is an alkali metal ion. Preferred examples are the myristyl and oleoyl methyl sarcosinates in the form of their sodiwn salts.

Cationic ester surfactant Essentially any cationic surfactants useful for detersive purposes are suitable for use herein either in combination with an aniomc surfactant as a NW surfactant or when present in less than 15% by weight of the surfactant system.

Cationic ester surfactants used in this invention are preferably water dispersible compound having surfactant properties comprising at least one ester (le -COO-) linkage and at least one cationically charged group.

Suitable cationic surfactants include the quaternary ammonium surfactants selected firorn mono C6-C 16, preferably C6-C 10 N-alkyl or alkenyl ammonium surfactants wherein the remaining N positions are substituted by methyl, hydroxyethyl or 1 hydroxypropyl groups. Other suitable cationic ester surfactants, including choline ester surfactants, have for example been disclosed in US Patents No.s 4228042, 4239660 and 4260529.

Dianionic surfactant The detergent composition of the present invention comprises a dianionic surfactant.

The dianionic surfactant is present at a level of from 1% to 50%, more preferably from 5 % to 40%, most preferably from 10% to 3 0% by weight of the surfactant system.

The dianionic surfactant of the present invention has an equivalent weight of less than 200. The equivalent weight of a surfactant is calculated by dividing the molecular weight of surfactant by the number of charged groups.

The dianionic surfactant of the present invention comprises a hydrophobic portion and a hydrophilic portion as described in "Detergents and Cleaners" by K Robert Lange (1994). The hydrophobic portion comprises a hydrocarbon chain preferably comprising carbon atoms. The hydrocarbon chain may comprise any of the following groups including alkyl, substituted alkyl, alkenyl, aryl, alkaryl, ether or ester groups and preferably comprises less than 14 carbon atoms, preferably less than 11. more preferably less than 9 or even 7 carbon atoms. The hydrocarbon chain may be linear or branched. Where the hydrocarbon chain is branched, preferably at least 10% by weight of the hydrocarbon chain is branched and the branches are preferably from 1 to 5, more preferably from I to 3, most preferably from I to 2 carbon atoms in length.

11 The hydrophilic portion comprises a hydrocarbon chain comprising from 2 to 5 atoms, preferably carbon atoms, to which two anionic groups are bonded. The anionic groups are spaced at a distance of up to 5 carbon atoms apart, that is to say for example, where a first anionic group is bonded to a first carbon, said first carbon is bonded to a second carbon, which is in turn, bonded to a third carbon and the third carbon is bonded to the second anionic group, providing a spacing of three carbon atoms between the first anionic group and the second anionic group. Alternatively, both anionic groups can be bonded to one carbon atom, preferably the terminal carbon atom.

It is an essential feature of the present invention that one of the anionic groups is terminally located. By terminally located it is meant that one of the anionic groups is bonded to the primary or terminal carbon atom at the end of the hydrocarbon chain of the hydrophilic portion which is not attached to the hydrocarbon chain of the hydrophobic portion. In a preferred aspect of the present invention the second anionic group is bonded to the second, third or fourth carbon atom in the hydrocarbon chain of the hydrophilic portion i.e. the anionic groups are 1,2, 1,3 or 1,4 substitutions, most preferably a 1,4 substitution. For full clarity, the term 1,n substitution is to be interpreted such that 1 indicates an anionic group located at the terminal position on the hydrocarbon chain and n indicates the number of atoms spaced between the first and second anionic groups.

The anionic groups can be selected from sulphate, sulphonate and carboxylate groups. It is envisaged that the first and second anionic groups may be the same or different.

Suitable dianionic surfactants include any of those commonly available on the market. In a preferred aspect of the present invention the dianionic surfactant is an cc-sulpho carboxylate wherein the first anionic group is a sulphonate group and is )o bonded to the terminal carbon atom and the second anionic group is a carboxylate 12 group and is also bonded to the terminal carbon atom. Preferred a-sulpho carboxylates comprise from 8 to 16 carbon atoms, more preferably from 8 to 14 carbon. Most preferably the dianionic surfactant is a disodium salt of a C12-14 asulpho carboxylate.

In another preferred aspect the first anionic group, bonded to the terminal carbon atom is a sulphate group and the second anionic group is preferably selected from the group consisting of sulfate, sulfonate and carboxylate groups. Most preferably the second anionic group is also a sulfate group. Preferred dianionic surfactants of this type are described in US patent application number 60/020,859, 601020,823, 60/020, 968 and 60/020,783. Examples of preferred dianionic surfactants are selected from the group consisting of alkyl 1,3 disulphate, alkyl 1,4 disulphate and alkyl 1,5 disulphate.

Detergent Compgnents The detergent compositions of the invention may also contain additional detergent components. The precise nature of these additional components, and levels of incorporation thereof will depend on the physical form of the composition, and the 20 precise nature of the washing operation for which it is to be used.

The compositions of the invention preferably contain one or more additional detergent components selected from bleaching agents, builder compounds, alkalinity system, organic polymeric compounds, enzymes. suds suppressers, lime soap dispersants. soil suspension and anti-redeposition a(yents and corrosion inhibitors.

C5 13 Water-soluble builder cornvound The detergent compositions of the present invention may contain a water- soluble builder compound, typically present at a level of from 1 % to 80% by weight, preferably from 10% to 70% by weight, most preferably from 20% to 60% by weight of the composition.

Suitable water-soluble builder compounds include the water soluble monomenc polycarboxylates, or their acid forms, horno 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, borates, phosphates, and mixtures of any of the foregoing.

The carboxylate or polycarboxylate builder can be mornomeric or oligomeric in type although monomeric polycarboxylates are generally preferred for reasons of cost and performance.

Suitable carboxylates containing one carboxy group include the water soluble salts of lactic acid, glycolic acid and ether derivatives thereof. Polycarboxylates containing two carboxy groups include the water-soluble salts of succinic acid, maloruic acid, (ethylenedioxy) diacetic acid, maleic acid, diglycolic acid. tartaric acid, tartronic acid and furnaric acid, as well as the ether carboxylates and the sulfinyl carboxylates.

Polycarboxylates containing three carboxy groups include. in particular, water soluble 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. 1,3 89,7') 2. and arninosuccinates described in Netherlands Application 720587-33, and the oxypolycarboxylate matenals such as 2-oxa-1,1.-'5-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 3-propane tetracarboxylates and 1, 1,2,3propane tetracarboxylates. Polycarboxylates containing 14 suifo 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. Preferred polycarboxylates are hYdroxycarboxylates containing up to three carboxy groups per molecule, more particularly citrates.

The parent acids of the monomeric or oligomenc polycarboxylate chelating agents or mixtures thereof with their salts, e.g. citric acid or citrate/citric acid mixtures are also contemplated as useful builder components.

Borate builders, as well as builders containing borate-forming materials that can L, produce borate under detergent storage or wash conditions are useful water-soluble builders herein.

Suitable examples of water-soluble phosphate builders are the alkali metal tripolyphosphates. sodium. potassium and ammonium pyrophosphate, sodium and potassiwn and ammonium pyrophosphate, sodium and potassium orthophosphate. sodium polymeta/phosphate in which the degree of polymerization ranges from about 6 to 2 1, and salts of ph-viic acid.

Water-m'soluble or partially soluble Builder COMD0und The detergent composition of the present invention preferably contains a waterinsoluble or partially soluble builder compound. Water-insoluble or partialb; soluble builder compounds include the aluminosilicates and the crystalline layered silicates- Suitable aluminosilicates include the aluminosilicate zeolites havin2 the unit cell 2 5 formula Naz[(A10.)YSi02M. xH.)0 wherein z and y are at least 6: the molar ratio of z to v is from 1.0 to 0.5 and x is at least 5. preferably from 7.5 to 276. more preferably from 10 to 264. The aluinMosilicate material are in hydrated form and are preferably crystalline. containing from 10% to 28%. more preferably from 18% to ')')% water in bound form.

is The aluminosilicate zeolites can be naturally occurring materials, but are preferably synthetically derived. Synthetic crystalline aluminosilicate ion exchange materials are available under the designations Zeolite A, Zeolite B, Zeolite P, Zeolite X, 5 Zeolite HS and mixtures thereof A preferred method of synthesizing aluminosilicate zeolites is that described by Schoeman et al (published in Zeofite (1994) 14(2), 110-116), in which the author describes a method of preparing colloidal aluminosilicate zeolites. The colloidal aluminosilicate zeolite particles should preferably be such that no more than 5% of the particles are of size greater than 1 gm in diameter and not more than 5% of particles are of size less then 0.05 pin in diameter. Preferably the aluminosilicate zeolite particles have an average particle size diameter of between 0. 0 1 gm and 1 pm, more preferably between 0.05 gm and 0.9 gm, most preferably between 0. 1 gm and 0.6 gm.

Zeolite A has the formula Na 12 [A102) 12 (Si02)121. x1120 wherein x is from 20 to 30, especially 27. Zeolite X has the formula Na86 [(A102)86(SiO2)1061. 276 H20. Zeolite, as disclosed in EP- B-3384,070 is a preferred zeolite builder herein.

Preferred alurninosilicate zeolites are the colloidal alurninosilicate zeolites. When employed as a component of a detergent composition colloidal aluminosilicate zeolites, especially colloidal zeolite A, provide enhanced builder performance in terms of providing improved stain removal. Enhanced builder performance is also seen in terms of reduced fabric encrustation and improved fabric whiteness o 16 maintenance; problems believed to be associated with poorly built detergent compositions.

A surprising finding is that mixed aluminosilicate zeOlite detergent compositions comprising colloidal zeolite A and colloidal zeolite Y provide equal calcium ion sequestration performance versus an equal weight of commercially available zeolite A. Another surprising finding is that mixed aluminosilicate zeolite detergent compositions, described above, provide improved magnesium ion sequestration performance versus an equal weight of commercially available zeolite A.

Preferred are the crystalline layered sodium silicates of general formula NaMSix02 +1 yH20 wherein M is sodium or hydrogen, x is a number from 1.9 to 4 and y is a number from 0 to 20. Crystalline layered sodium silicates of this type preferably have a two dimensional 'sheet' structure, such as the so called 8-layered structure, as described in EP 0 164514 and EP 0 293640.

Methods for preparation of crystalline layered silicates of this type are disclosed in DE-A-3417649 and DE-A-3742043. For the purpose of the present invention, x in the general formula above has a value of 2,3 or 4 and is preferably 2.

The most preferred crystalline layered sodium silicate compound has the formula 5Na2Si2O5, known as NaSKS-6 (trade name), available ftom Hoechst AG.

The crystalline layered sodium silicate material is preferably present in granular detergent compositions as a particulate in intimate admixture with a solid, watersoluble ionisable material as described in PCT Patent Application No. W092/18594. The solid, water-soluble ionisable material is selected from organic 17 acids, organic and inorganic acid salts and mixtures thereof, with citric acid being preferred.

Organic proMyacid bleaching system A preferred feature of detergent compositions of the invention is an organic peroxyacid bleaching system. In one preferred execution the bleaching system contains a hydrogen peroxide source and an organic peroxyacid bleach precursor compound. The production of the organic peroxyacid occurs by an in situ reaction of the precursor with a source of hydrogen peroxide. Preferred sources of hydrogen peroxide include inorganic perhydrate bleaches. In an alternative preferred execution a preformed organic peroxyacid is incorporated directly into the composition.

Compositions containing mixtures of a hydrogen peroxide source and organic peroxyacid precursor in combination with a preformed organic peroxyacid are also gn envisaged.

Inorganic perhydrate bleaches Inorganic perhydrate salts are a preferred source of hydrogen peroxide. These salts are normally incorporated in the form of the alkali metal, preferably sodium salt at a level of from 1% to 40% by weight, more preferably from 2% to 30% by weight and mostpreferably 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. Suitable coatings comprise inorganic salts such as alkali metal silicate, carbonate or borate salts or mixtures thereof, or organic materials such as waxes, oils, 3 )o or fatty soaps.

18 Sodium perborate is a preferred perhydrate salt and can be in the form of the monohydrate of nominal formula NaB02H202 or the teft-ahydrate NaB02H202.3H20.

i metal percarbonates, particularly sodium percarbonate are preferred perhydrates herein. Sodium percarbonate is an addition compound having a formula corresponding to 2Na2C03.3H202, and is available commercially as a crystalline solid.

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

PeroMyacid bleach precursor Peroxyaeld bleach precursors are compounds which react with hydrogen peroxide in a perhydrolysis reaction to produce a peroxyacid. Generally peroxyacid bleach precursors may be represented as 0 X-C-L where L is a leaving group and X is essentially any functionality. such that on perhydroloysis the structure of the peroxyacid produced is 0 X-C OOH Peroxyacid bleach precursor compounds are preferably incorporated at a level of from 0.5% to 20% by weight, more preferably from 1 % to 15% by weight. most preferably from 1. 5% to 10% by weight of the detergent compositions.

19 Suitable peroxyacid bleach precursor compounds typically contain one or more N- or 0-acyl groups, which precursors can be selected from a wide range of classes.

Suitable classes include anhydrides, esters, imides, lactains and acylated derivatives of imidazoles and oximes. Examples of useful materials within these classes are disclosed in GB-A-1586789. Suitable esters are disclosed in GB-A-836988, 864798, 1147871, 2143231 and EP-A-0170386.

Leaving groMps The leaving group, hereinafter L group, must be sufficiently reactive for the perhydrolysis reaction to occur within the optimum time frame (e.g., a wash cycle).

However, if L is too reactive, this activator will be difficult to stabilize for use in a bleaching composition.

Preferred L ups are selected from the group consisting of gro c 0 0 11 A il -N-C-Rl -N N -N-U-Utl-R4 1 3 i 1 1 1 R Li R 3 Y i Y R3 1 -0-CH=C-CH=CH2 Y 1 -0-upi=u-CH=CH2 1 0 11 0 CH2-C IL -N / 11 U 1 R3 1 -0-C=CHR4, and 1 0 Y 11 1 -N-S-CH-R4 1 11 R 3 0 0 Y -N NR4 c 11 U and mixtures thereof, wherein R' is an alkyl, aryl, or 1 group containing from 1 to 14 carbon atoms, W' is an alkyl chain containing 4 3 from 1 to 8 carbon atoms, R is H or R ' and Y is H or a solubilizing 1 3 4 group. Any of R R and R may be substituted by essentially any flinctional group including. for example alkyl. hydroxy. alkoxy. halogen, amine, nitrosyl, amide and ammonium or alkyl amnimonium, groups 1 + + + - +3 The preferred solubilizing groups are -SO.,-M ' -CO - m _so - m ' N (R 2 4)4X and 0<-N(R3), and most preferably -SO, -M-- and -CO.,-M wherein R3 is an alkyl chain containing ftom 1 to 4 carbon atoms, M is a cation which provides solubility to the bleach activator and X is an anion which provides solubility to the bleach activator. Preferably. M is an alkali metal, ammonium or substituted ammonium cation, with sodium and potassium being most preferred, and X is a halide, hydroxide. methylsulfate or acetate anion.

21 AMI p2rcarboLcylic acid bleach pagursors Alkyl percarboxylic acid bleach precursors form percarboxylic: acids on perhydrolysis. Preferred precursors of this type provide peracetic acid on 5 perhydrolysis.

Preferred alkyl percarboxylic precursor compounds of the imide type include the N- N,N IN I tetra acetylated alkylene diamines wherein the alkylene group contains from 1 to 6 carbon atoms, particularly those compounds in which the alkylene group contains 1, 2 and 6 carbon atoms. Tetraacetyl ethylene diamine (TAED) is 10 particularly preferred.

Other preferred alkyl percarboxylic acid precursors include sodium 3,5,5tri-methyl hexanoyloxybenzene suifonate (iso-NOBS), sodium nonanoyloxybenzene sulfonate (NOBS), sodium acetoxybenzene suifonate (ABS) and pentaacetyl glucose.

Amide substituted alkyl pgroxyacid precursors Amide substituted alkyl peroxyacid precursor compounds are suitable herein, including those of the following general formulae:

R' ----C- - -N-R2- C-L R' -N-C-R2-C-L 0 R5 0 or R5 0 0 wherein R I is an alkyl group with from 1 to 14 carbon atoms, R2 is an alkylene group containing ftom 1 to 14 carbon atoms, and R5 is H or an alkyl group containing 1 to 10 carbon atoms and L can be essentially any leaving group. Arnide substituted bleach activator compounds of this type are described in EP-A-0 1703 86.

22 1 Perbenzoic acid pmúursor Perbenzoic acid precursor compounds provide perbenzoic acid on perhydrolysis.

Suitable 0-acylated perbenzoic acid precursor compounds include the substituted and unsubstituted benzoyl oxybenzene sulfonates, and the benzoylation products of sorbitol, glucose, and all saccharides with benzoylating agents, and those of the imide type including N-benzoyl succinimide, tenzoyl ethylene diamine and the N-benzoyl substituted ureas. Suitable imidazole type perbenzoic acid precursors include N-benzoyl imidazole and N-benzoyl benzimidazole. Other useful N- acyl group-containing perbenzoic acid precursors include N-benzoyl pyrrolidone, dibenzoyl taurine and benzoyl pyroglutarnic acid.

Cationic prolcyacid precursors Cationic peroxyacid precursor compounds produce cationic peroxyacids on perhydrolysis.

Typically, cationic peroxyacid precursors are formed by substituting the peroxyacid part of a suitable peroxyacid precursor compound with a positively charged functional group, such as an ammonium or alkyl aminmonium group, preferably an ethyl or methyl ammonium group. Cationic peroxyacid precursors are typically present in the solid detergent compositions as a salt with a suitable anion, such as a halide ion.

The peroxyacid precursor compound to be so cationically substituted may be a perbenzoic acid, or substituted derivative thereof, precursor compound as described hereinbefore. Alternatively, the peroxyacid precursor compound may be an alkyl percarboxylic acid precursor compound or an amide substituted alkyl peroxyacid precursor as described hereinafter 23 Cationic peroxyacid precursors are described in U.S. Patents 4,904,406; 4,751,015; 4,988,451; 4,397,757; 5,269,962; 5,127,852; 5,093,022; 5,106,528; U.K. 1,382,594; EP 475,512, 458,396 and 284,292; and in JP 87318,332.

Examples of preferred cationic peroxyacid precursors are described in UK Patent Application No. 9407944.9 and US Patent Application Nos. 08/298903, 08/298650, 08/298904 and 08/298906.

Suitable cationic peroxyacid precursors include any of the ammonium or alkyl ammonium substituted alkyl or benzoyl oxybenzene sulfonates, Nacylated caprolactams, and monobenzoyltetraacetyl glucose benzoyl peroxides. Preferred cationic peroxyacid precursors of the N-acylated caprolactam class include the trialkyl ammonium methylene benzoyl caprolactams and the trialkyl ammonium methylene alkyl caprolactams.

Benzoxazin organic pgroxyacid precursors Also suitable are precursor compounds of the benzoxazin-type, as disclosed for example in EP-A-332,294 and EP-A-482,807, particularly those having the formula:

0 11 L 0 1 [0 N //U-K1 wherein R, is H, alkyl, alkaryl, aryl, or arylalkyl.

24 Preformed organic MoLcyacid The organic peroxyacid bleaching system may contain, in addition to, or as an alternative to, an organic peroxyacid bleach precursor compound, a preformed organic peroxyacid, typically at a level of from 1 % to 15% by weight, more preferably from 1 % to 10% by weight of the composition.

A preferred class of organic peroxyacid compounds are the amide substituted compounds of the following general formulae:

R' -C-N-R2-C-OOH 0 R5 0 or R' -N-C-R2-C-OOH R5 0 0 wherein RI is an alkyl, aryl or alkaryl group with from 1 to 14 carbon atoms, R2 is an alkylene, arylene, and alkarylene group containing from 1 to 14 carbon atoms, and R5 is H or an alkyl, aryl, or 1 group containing 1 to 10 carbon atoms. Amide substituted organic peroxyacid compounds of this type are described in EP-A0170386.

Other organic peroxyacids include diacyl and tetraacylperoxides, especially diperoxydodecanedioc acid, diperoxytetradecanedioc acid and diperoxyhexadecanedioc acid. Mono- and diperazelaic acid. mono- and diperbrassylic acid and N-phthaloylaminoperoXicaproic acid are also suitable herein.

Metal-containing bleach catalyst The compositions described herein may Optionally include a metal containing bleach catalyst. A suitable type of bleach catalyst is a catalyst comprising a heavy metal cation of defined bleach catalytic activity, such as copper, iron or manganese cations, an auxiliary metal cation having little or no bleach catalytic activity, such as zinc or aluminum cations, and a sequestrant having defined stability constants for the catalytic and auxiliary metal cations, particularly ethylenediaminetetraacetic acid, ethylenediaminetetra (methylenephosphonic acid) and water-soluble salts thereof Such catalysts are disclosed in U.S. Pat. 4,430,243.

Other types of bleach catalysts include the manganese-based complexes disclosed in U.S. Pat. 5,246,621 and U.S. Pat. 5,244,594. Preferred examples of these catalysts include MnIV2(u-0)3(1,4,7-trimethyl-1,4,7-triazacyclononane)2-(PF6)2, N4n",2(u0)1(u-OAc)2(1,4,7-timethyl-1,4,7-triazacyclononane)2-(CI04)2, MnIV4(u0)6(1,4,7-triazacyclononane)4-(CI04)2, Mn",MnIV4(u-0) I (u-OAc)2-(1,4,7trimethyl-1,4,7-triazacyclononane)2-(CI04)3, and mixtures thereof. Others are described in European patent application publication no. 549,272. Other ligands suitable for use herein include 1,5,9-trimethyl- 1,5,9triazacyclododecane, 2-methyl1,4,7-triazacyclononane, 2-methyl-1,4,7triazacyclononane, 1,2.4,7-tetramethyl- 1,4,7-triazacyclononane, and mixtures thereof.

For examples of suitable bleach catalysts see U.S. Pat. 4.246,612 and U.S. Pat. 5,227,084. See also U.S. Pat. 5,194,416 which teaches mononuclear manganese (IV) complexes such as Mn(1,4,7-timethyl-1,4,7tiriazacyclononane)(OCH-,)-I-(PFr,). Still another type of bleach catalyst, as disclosed in U.S. Pat. 5.114,606, is a water-soluble 20 complex of manganese (III), and/or (IV) with a ligand which is a non-carboxylate polyhydroxy compound having at least three consecutive C-OH g oups. Other gr examples include binuclear Mn complexed with tetra-N-dentate and bi-N- dentate ligands, including N4N4n','(u-0)2MnIVN4)'and [BiPY2Mnll(u-0)2MnlVbiPY2](C 104).3 3 Further suitable bleach catalysts are described, for example, in European patent application No. 408,133 1 (cobalt complex catalysts), European patent applications, publication nos. 384,503), and 306,089 (metallo- porphyrin catalysts), U.S. 4,728,455 (manganese/multidentate ligand catalyst), U.S. 4,711,748 and European patent 26 application, publication no. 224,952, (absorbed manganese on aluminosilicate catalyst), U.S. 4,601,845 (aluminosilicate support with manganese and zinc or magnesium salt), U.S. 4,626,373 (manganesefligand catalyst), U.S. 4,119,557 (ferric complex catalyst), German Pat. specification 2,054,019 (cobalt chelant catalyst) Canadian 866,191 (traiisition metal-containing salts), U.S. 4,430,243 (chelants with manganese cations and non-catalytic metal cations), and U.S. 4,728,455 (manganese gluconate catalysts).

Alkalinill system An optional component of the detergent compositions is from 1.5% to 95%, preferably from 5% to 60%, most preferably from 10% to 40% by weight of the composition of an alkalinity system comprising components capable of providing alkalinity species in solution. By alkalinity species it is meant for the purposes of this invention: carbonate, bicarbonate, hydroxide and the various silicate anions. Such alkalinity species can be formed for example, when alkaline salts selected from alkali metal or alkaline earth carbonate, bicarbonate, hydroxide or silicate, including crystalline layered silicate. salts and any mixtures thereof are dissolved in water. Alkali metal percarbonate and persilicate salts are also suitable sources of alkalinity 20 species.

Detergent compos, i fi itions speci ically formulated for use in automatic dishwashing preferably contains sodium metasilicate. present at a level of at least 0. 4% SiO.) by weight. Sodium metasilicate has a nominal SIO.) Na.)0 ratio of 1.0. The weight ratio of said sodium silicate to said sodium 2 5 metasilicate. measured as SiO-, is preferably from 50:1 to 5A, more preferably from 15: 1 to 2: 1, most preferably from 10: 1 to 52.

27 HEM metal ion gNuestrant The detergent compositions of the invention preferably contain as an optional component a heavy metal ion sequestrant. By heavy metal ion sequestrant it is meant herein components which act to sequester (chelate) heavy metal ions. Ilese components may also have calcium and magnesium chelation capacity, but preferentially they show selectivity to binding heavy metal ions such as iron, manganese and copper.

Heavy metal ion sequestrants are generally present at a level of from 0. 005% to 20%, preferably from 0. 1 % to 10%, more preferably from 0.25% to 7.5% and most preferably from 0.5% to 5% by weight of the compositions.

Suitable heavy metal ion sequestrmts for use herein include organic phosphonates, such as the amino alkylene poly (alkylene phosphonates), alkali metal ethane I hydroxy disphosphonates and nitrilo trimethylene phosphonates.

Preferred among the above species are diethylene triamine penta (methylene phosphonate), ethylene diamine tri (methylene phosphonate) hexamethylene diamme tetra (methylene phosphonate) and hydroxy-ethylene 1, 1 diphosphonate.

Other suitable heavy metal ion sequesumt for use herein include nitrilotriacetic acid and polyaminocarboxylic acids such as ethylenediaminotetracetic acid, ethylenetriamine pentacetic acid, ethylenediamine disuccinic acid, ethylenediamine diglutaric acid, 2-hydroxypropylenediamine disuccinic acid or any salts thereof. Especially preferred is ethylenediamine-N,N'- disuccinic acid (EDDS) or the alkali metal, alkaline earth metal, ammonium, or substituted ammonium salts thereof, or mixtures thereof.

Other suitable heavy metal ion sequestrants for use herein are iminodiacetic acid denvatives such as 2-hydroxyethyl diacetic acid or glyceryl imino diacetic acid, described in EP-A-3) 17,542 and EP-A-399,1 33. The iminodiacetic acid-N-2 hydroxypropyl sulfonic acid and aspartic acid N-carboxymethyl N-2- hydroxypropyl- 1 :)-suifonic acid sequestrants described in EP-A-516,102 are also suitable herein. The 28 P-alanine-N,N'-diacetic acid, aspartic acid-NN'-diacetic acid, aspartic acid-Nmonoacetic acid and iminodisuccinic acid sequestrants described in EP-A-509,382 are also suitable.

EP-A-476,257 describes suitable amino based sequestrants. EP-A-510,331 describes suitable sequestrants derived from collagen, keratin or casein. EP-A-528, 859 describes a suitable alkyl iminodiacetic acid sequestrant. Dipicolinic acid and 2 phosphonobutane- 1,2,4-tricarboxylic acid are also suitable. Glycinamide- NN' disuccinic acid (GADS), ethylenediamine-N-N'-diglutaric acid (EDDG) and 2 hydroxypropylenediamme-N-N'-disuceinic acid (IIPDDS) are also suitable.

Water-soluble sulfate salt The compositions may optionally contain a water-soluble sulfate salt, preferably present at a level of from 0. 1 % to 40%, more preferably from I % to 3 0%, most preferably from 5% to 25% by weight of the compositions.

The water-soluble sulfate salt may be essentially any salt of sulfate with any counter cation. Preferred salts are selected from the sulfates of the alkali and alkaline earth metals, particularly sodium sulfate.

0 Corrosion inhibitor compo d The compositions may contain corrosion inhibitors preferably selected from organic silver coating agents. particularly paraffin, nitrogen- containing corrosion inhibitor compounds and Mn(I1) compounds, particularly Mn(I1) salts of organic ligands.

Organic silver coating agents are described in PCT Publication No. W094/16047 (attorney's docket no. CM497M) and copending UK Application No. UK 9413729.6 (attorney's docket no. CM750F). Nitrogen-containing corrosion inhibitor compounds are disclosed in copending European Application no. EP 93202095.1 (attorney's docket no. CM571F). N4n(II) compounds for use in corrosion inhibition 29 are described in copending UK Application No. 9418567.5 (attorney's docket no.

CM719FM).

PolyMeric Soil Release Agents The detergent composition of the present invention may also contain a polymeric soil release agent. Suitable polymeric soil release agents include those soil release agents having: (a) one or more nonionic hydrophile components consisting essentially of (i) polyoxyethylene segments with a degree of polymerization of at least 2. or (11) oxypropylene or polyoxypropylene segments with a degree of polymenzation of from 2 to 10, wherein said hydrophile segment does not encompass any oxypropylene unit unless it is bonded to adjacent moieties at each end by ether linkages, or (iii) a mixture of oxyalkylene units comprising oxyethylene and from 1 to about 30 oxypropylene umts, said hydrophile segments preferably compnisincy at least about 25% oxyethylene units and more preferably, especially for such components having about 20 to 30 oxypropylene units, at least about 50% oxyethylene units, or (b) one or more hydrophobe components comprising (1) C-, oxyalkylene terephthalate segments, wherein, if said hydrophobe components also comprise oxyethylene terephthalate. the ratio of oxyethylene terephthalate:C3 oxyalkylene terephthalate umts is about 2:1 or lower. C4-C6 alkylene or Ox% C4- C6 alkylene segments, or mixtures therein, (iii) poly (vinyl ester) segments, preferably polyvinyl acetate. having a degree of polymerization of at least I or Ii") C I -C4 al kyl ether or C4 hydroxyalkyl ether substituents. or mixtures therein, wherein said substituents are present in the form Of C I -C4 alkyl ether or C4 hydroxyalkyl ether cellulose derivatives. or mixtures therein. or a combination of (a) and (b).

1 Typically, the polyoxyethylene segments of (aXi) will have a degree of polymerization of from about 200, although higher levels can be used, preferably from 3 to about 150, more preferably from 6 to about 100. Suitable oxy C4-C6 alkylene hydrophobe segments include, but are not limited to, end-caps of polymeric soil release agents such as M03S(CH2)nOCH2CH20-, where M is sodium and n is an integer from 4-6, as disclosed in U.S. Patent 4,721,580, issued January 26, 1988 to Gosselink.

Polymeric soil release agents useful herein also include cellulosic derivatives such as hydroxyether cellulosic polymers, copolymeric blocks of ethylene tereptithalate or propylene terephthalate with polyethylene oxide or polypropylene oxide terephthalate, and the like. Such agents are comm ially available and include hydroxyethers of cellulose such as NffiTHOCEL (Dow). Cellulosic soil release agents for use herein also include those selected from the group consisting Of C I -C4 alkyl and C4 hydroxyalkyl cellulose; see U.S. Patent 4,000,093, issued December 28.

1976 to Nicol, et al.

Soil release agents characterized by poly(vinyl ester) hydrophobe segments include graft copolymers of poly(vinyl ester), e.g., C I -C6 vinyl esters, preferably poly(vinyl acetate) grafted onto polyalkylene oxide backbones, such as polyethylene oxide backbones. See European Patent Application 0 219 048, published April 22, 1987 by 20 Kud, et al.

Another suitable soil release agent is a copolymer having random blocks of ethylene terephthalate and polyethylene oxide (PECI) terephthalate. The molecular weight of this polymeric soil release agent is in the range of from about 25,000 to about 55,000. See U.S. Patent 3,959,230 to Hays, issued May 25, 1976 and U.S. Patent 3),893,929 to Basadur issued July 8, 1975.

Another suitable polymeric soil release agent is a polyester with repeat units of ethylene terephthalate units contains 10- 15% by weight of ethylene terephthalate units together with 90-80% by weight of polyoxyethylene terephthalate units, derived from a polyoxyethylene glycol of average molecular weight 300-5,000.

Another suitable polymeric soil release agent is a sulfonated product of a substantially linear ester oligomer comprised of an oligomeric ester backbone of terephthaloyl and oxyalkyleneoxy repeat units and terminal moieties covalently attached to the backbone. These soil release agents are described ftilly in U.S. Patent 4,968,45 1, issued November 6, 1990 to J. J. Scheibel and E.P. Gosselink. Other suitable polymeric soil release agents include the terephthalate polyesters of U.S. Patent 4,711,730, issued December 8, 1987 to Gosselink et al, the anionic end- capped oligomeric esters of U.S. Patent 4,721,580, issued January 26, 1988 to Gosselink, and the block polyester oligomeric compounds of U.S. Patent 4. 702,857, issued October 27, 1987 to Gosselink. Other polymeric soil release agents also include the soil release agents of U.S. Patent 4,877, 896, issued October '31, 1989 to Maldonado et al, which discloses anionic, especially sulfbarolyl. end-capped terephthalate esters.

Another soil release agent is an oligomer with repeat units of terephthaloyl units, sulfoisoterephthaloyl units, oxyethyleneoxy and oxy1.2-propylene units. The repeat units form the backbone of the oligomer and are preferably terminated with modified isethionate end-caps. A particularly preferred soil release agent of this type comprises about one sulfoisophthaloyl unit, 5 terephthaloyl units. oxyethyleneoxy and oxy1,2-propyleneoxy units in a ratio of from about 1. 7 to about 1. 8. and two end-cap units of sodium 2-(2-hydroxyethoxy)- ethanesulfonate.

Mn(I1) corrosion inhibitor compounds The compositions may contain an Mn(I1) corrosion inhibitor compound. The N1WII) compound is preferabily incorporated at a level of from 0.005% to 5% by weight. more preferably ftom 0.01% to 1%. most preferably from 0. 02% to 0.4% by weight of the compositions. Preferably. the Mn(I1) compound is incorporated at a level to 32 provide from 0. 1 ppm to 250 ppm, more preferably from 0.5 ppm to 50 ppm, most preferably from 1 ppm to 20 ppm by weight of Mn(I1) ions in any bleaching solution.

The Mn (II) compound may be an inorganic salt in anhydrous, or any hydrated forms. Suitable salts include manganese sulphate, manganese carbonate, manganese 5 phosphate, manganese nitrate, manganese acetate and manganese chloride. The Mn(H) compound may be a salt or complex of an organic fatty acid such as manganese acetate or manganese stearate.

The Mn(II) compound may be a salt or complex of an organic ligand. In one preferred aspect the organic ligand is a heavy metal ion sequestrant. In another preferred aspect the organic ligand is a crystal growth inhibitor.

Other corrosion inhibitor comp2unds Other suitable additional corrosion inhibitor compounds include, mercaptans and diols, especially mercaptans with 4 to 20 carbon atoms including lauryl mercaptan, thiophenol, thionapthol, thionalide and thioanthranol. Also swtable are saturated or unsaturated C 1 O-C20 fatty acids, or their salts, especially aluminium tristearate. The C 12-C20 hydroxy fatty acids, or their salts, are also suitable. Phosphonated octa- decane and other anti-oxidants such as betahydroxytoluene (BHT) are also suitable.

Copolymers of butadiene and maleic acid, particularly those supplied under the trade reference no. 07787 by Polysciences Inc have been found to be of particular utility as corrosion inhibitor compounds.

Enzvme Another preferred ingredient useful in the detergent compositions is one or more additional enzymes.

33 Preferred additional enzymatic materials include the commercially available lipases, cutinases, amylases, neutral and alkaline proteases, esterases, cellulases, pectinases, lactases; 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, Primase, Durazym, and Esperase by Novo Industries A/S (Denmark), those sold under the traden-ame Maxatase, Maxacal and Maxapern by Gist-Brocades, those sold by Genencor International, and those sold under the tradename Opticlean and Optimase by Solvay Enzymes. Protease enzyme may be 10 incorporated into the compositions in accordance with the invention at a level of from 0.0001% to 4% active enzyme by weight of the composition.

Preferred amylases include, for example, cc-amylases obtained from a special strain of B licheniformis, 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 0.000 1 % to 2% active enzyme by weight of the composition.

Lipolytic enzyme 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. 00 1 % to 0.5% by weight of the compositions.

The lipase may be fungal or bacterial in origin being obtained, for example, from a lipase producing strain of Humicola sp., Therinomyces sp. or Pseudomonas sp.

including 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 PseudornonaS Dseudoalcaligenes. which is described in Granted European Patent, EP-B-0218272.

Another preferred lipase herein is obtained by cloning the gene from Hurnicola lanuginos and expressing the gene in AsRúrgillus ory as host, as described in 34 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.

Organic p21yMeric comR2und 2 Organic polymeric compounds are preferred additional components of the detergent compositions in accord with the invention, and are preferably present as components of any particulate components where they may act such as to bind the particulate component together. By organic polymeric compound it is meant herein essentially any polymeric organic compound commonly used as dispersants, and antiredeposition and soil suspension agents in detergent compositions, including any of the high molecular weight organic polymeric compounds described as clay flocculating agents herein.

Organic polymeric compound is tv pically incorporated in the detergent compositions of the invention at a level of from 0. 1 % to 30%. preferably from 0.5% to 15%, most preferably from 1% to 10% by weight of the compositions.

Examples of organic polymeric compounds include the water soluble orgaruic homoor 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 of the latter type are disclosed in GB-A-1.596,756. Examples of such salts are polyacrylates of MWt 2000-5000 and their copolymers with maleic anhydride, such copolymers having a molecular weight of from 20.000 c to 100,000, especially 40,000 to 80,000.

The polyarnino 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.

Terpolymers containing monomer units selected from maleic acid, acrylic acid, polyaspartic acid and vinyl alcohol, particularly those having an average molecular weight of from 5,000 to 10,000. are also suitable herein.

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

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

Crystal glowth inhibitor compMent The detergent compositions preferably contain a crystal growth inhibitor component, preferably an organodiphosphonic acid component, incorporated preferably at a level of from 0.0 1 % to 5%, more preferably from 0. 1 % to 2% by weight of the compositions.

By organo diphosphomc acid it is meant herein an organo diphosphonic acid 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 of the invention as heavy metal ion sequestrant components.

The organo diphosphonic acid is preferably a C 1 -C4 diphosphonic acid, more preferably a Q? diphosphonic acid, such as ethylene diphosphonic acid, or most preferably ethane 1 -hydroxy- 1, 1 -diphosphonic acid (HEDP) and may be present in partially or fully ionized form, particularly as a salt or complex.

Lime soap disRersant comp2und The compositions of the invention may contain a lime soap dispersant compound, 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.

36 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. Preferred lime soap disperant compounds are disclosed in PCT Application No. W093/08877 (attorney's docket no. CM466M).

Suds sgppressiniz system The detergent compositions of the invention, when formulated for use in machine washing compositions, preferably comprise a suds suppressing system present at a level of from 0.01% to 15%, preferably from 0.05% to 10%, most preferably from 0. 1 % to 5% by weight of the composition.

Suitable suds suppressing systems for use herein may comprise essentially any known antifoam compound, including, for example silicone antifoarn compounds and 2-alkyl alcanol 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 antifoarn 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. Preferred silicone antifoam compounds are the slioxanes, particularly the polydimethylsiloxanes having tnmeth,,llsllyl end blocking units.

Other suitable antifoarn 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 24 37 1 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 fatty esters (e.g. fatty acid triglycerides), fatty acid esters of monovalent alcohols, aliphatic C I 8-C40 ketones (e.g. stearone) Nalkylated 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 I to 24 carbon atoms, propylene oxide, bis stearic acid amide and monostearyl di-alkali metal (e.g. sodium, potassium, lithium) phosphates and phosphate esters.

A preferred suds suppressing system comprises:

(a)antifoam compound, preferably silicone antifoam compound, most preferably a silicone antifoarn compound comprising in combination (i) polydimethyl siloxane, at a level of from 50% to 99%, preferably 75% to 95% by weight of the silicone antifoarn compound; and (11) silica. at a level of from 1% to 50%, preferably 5% to 25% by weight of the silicone/silica antifoam compound; wherein said silica/silicone antifoam compound is incorporated at a level of from 5% to 50%. preferably 10% to 40% by weight; (b)a dispersant compound, most preferably comprising a silicone glycol rake copolymer with a polyoxyalkylene content of 72-78% and an ethylene oxide to propylene oxide ratio of from 1:0.9 to 1: 1. 1, at a level of from 0.5% to 10%, preferably 1 % to 10% by weight; a particularly preferred silicone glycol rake copolymer of this type is DC0544, commercially available from DOW Corning under the tradename DC0544; 38 (c) an inert carrier fluid compound, most preferably comprising a C 1 6-C 18 ettioxylated alcohol with a degree of ethoxylation of from 5 to 50, preferably 8 to 15, at a level of from 5% to 80%, preferably 10% to 70%, by weight; A highly preferred particulate suds suppressing system is described in EP- A-0210731 and comprises a silicone antifoam compound and an organic carrier material having a melting point in the range 50'C to 85'C, wherein the organic carrier material comprises a monoester of glycerol and a fatty acid having a carbon chain containing from 12 to 20 carbon atoms. EP-A-0210721 discloses other preferred particulate suds suppressing systems wherein the organic carrier material is a fatty acid or alcohol having a carbon chain containing from 12 to 20 carbon atoms, or a mixture thereof, with a melting point of from 45'C to 80'C.

Clav softening system The detergent compositions may contain a clay softening system comprising a clay mineral compound and optionally a clay flocculating agent.

The clay mineral compound is preferably a smectite clay compound. Smectite clays are disclosed in the US Patents No.s 3,862,058, 3,948,790, 3,954,632 and 4,062,647.

European Patents No.s EP-A-299,575 and EP-A-313,146 in the name of the Procter and Gamble Company describe suitable organic polymeric clay flocculating agents.

Polvmeric dye transfer inhibiting aRents The detergent compositions herein may also comprise from 0.01% to 10 %, preferably from 0.05% to 0.5% by weight of polymeric dye transfer inhibiting agents.The polymeric dye transfer inhibiting agents are preferably selected from polyamMe N-oxide polymers, copolymers of N- vinylpyrrolidone and Nvinylimidazole, polyvinylpyrrolidonepolymers or combinations thereof.

39 a) Polvamine N-oxide pglyffiers Polyamine N-oxide polymers suitable for use herein contain units having the following structure formula:

p (1) Ax wherein P is a polymerisable unit, and 00 0 A is NC, CO, C, -0-, -S-, -N-; x is 0 or 1; R are aliphatic, ethoxylated aliphatics, aromatic, heterocyclic or alicyclic groups or any combination thereof whereto the nitrogen of the N- 0 group can be attached or wherein the nitrogen of the N-0 group is part of these groups.

The N-O group can be represented by the following general structures:

0 A 0 A (R,) x -W(R2)y (R3)z or = W(R1)x wherein R I, R2, and R3 are aliphatic groups, aromatic, heterocyclic or alicyclic groups or combinations thereof, x or/and y or/and z is 0 or I and wherein the nitrogen of the N-0 group can be attached or wherein the nitrogen of the N-0 group forins part of these groups. The N-0 group can be part of the polyrnerisable unit (P) or can be attached to the polymeric backbone or a combination of both.

Suitable polyamine N-oxides wherein the N-0 group forms part of the polymerisable unit comprise polyarnine N-oxides wherein R is selected from aliphatic, aromatic, alicyclic or heterocyclic groups. One class of said polyamine N-oxides comprises the group of polyamine N-oxides wherein the nitrogen of the N-0 group forms part of the R-group. Preferred polyamine N-oxides are those wherein R is a heterocyclic group such as pyrridine, pyrrole, imidazole, pyrrolidine, piperidine, quinoline, acridine and derivatives thereof.

Other suitable polyamine N-oxides are the polyamine oxides whereto the N0 group is attached to the polymerisable unit. A preferred class of these polyamine N-oxides comprises the polyamine N-oxides having the general formula (1) wherein R is an aromatic,heterocyclic or alicyclic groups wherein the nitrogen of the N-0 functional group is part of said R group. Examples of these classes are polyarnine oxides wherein R is a heterocyclic compound such as pyrridine, pyrrole, imidazole and derivatives thereof.

The polyarnine N-oxides can be obtained in almost any degree of polymerisation. The degree of polymerisation is not critical provided the material has the desired water-solubility and dye-suspending power. Typically, the average molecular weight is within the range of 500 to 1000,000.

b) Copolymers of N-vinvipWolidone and N-vinylimidazole Suitable herein are coploymers of N-vinylimidazole and N-vinylpyrrolidone having an average molecular weight range of from 5,000 to 50.000. The preferred copolymers have a molar ratio of N-vinylimidazole to N-vinylpyrrolidone from 1 to 0.2.

c ) Polyvinylpyrrolidone The detergent compositions herein may also utilize polyvinylpyrrolidone ("PW") having an average molecular weight of from 2,500 to 400,000. Suitable polyvinylpyrrolidones are commercially available from ISP Corporation, New York.

41 NY and Montreal, Canada under the product names PVP K- 15 (viscosity molecular weight of 10,000), PVP K-30 (average molecular weight of 40, 000), PVP K-60 (average molecular weight of 160,000), and PVP K-90 (average molecular weight of 360,000). PVP K- 15 is also available from ISP Corporation. Other suitable polyvinylpyrrolidones which are commercially available from BASF Cooperation include Sokalan HP 165 and Sokalan HP 12.

d) Polyvinyloxazolidone The detergent compositions herein may also utilize polyvinyloxazolidones as polymeric dye transfer inhibiting agents. Said polyvinyloxazolidones have an average molecular weight of from 2,500 to 400,000.

e) Polyyinylimidazole The detergent compositions herein may also utilize polyvinyl imidazole as polymeric dye transfer inhibiting agent. Said polyvinylimidazoles preferably have an average molecular weight of from 2,500 to 400,000.

Optical brightener The detergent compositions herein also optionally contain from about 0. 005% to 5% by weight of certain types of hydrophilic optical brighteners.

Hydrophilic optical brighteners useful herein include those having the structural formula:

R, N H H N N 0/- N N-ON -Q H 1 1 R 7::N H S03M N::! R, S03M R, 42 wherein RI is selected from anilino, N-2-bis-hydroxyethyl and NH-2- hydroxyethyl; R2 is selected ftom N-2-bis-hydroxyethyl, N-2-hydroxyethyl- N-methylamino, morphilino, chloro and amino; and M is a salt-forming cation such as sodium or potassium.

When in the above formula, RI is anilino, R2 is N-2-bis-hydroxyethyl and M is a cation such as sodium, the brightener is 4,4',-bis[(4-anilino-6-(N-2bishydroxyethyl)-s-triazine-2-yl)aminol-2,2'-stilbenedisulfonic acid and disodium salt. This particular brightener species is commercially marketed under the tradename Tinopal-UNPA-GX by Ciba-Geigy. Corporation. Tinopal-UNPA-GX is the preferred hydrophilic optical brightener useful in the detergent compositions herein.

When in the above formula, RI is anilino, R2 is N-2-hydroxyethyl-N-2methylamino and M is a cation such as sodium, the brightener is 4,4'-bis[(4-anilino-6(N-2hydroxyethyl-N-methylamino)-s-triazine-2-yl)ammo]2,2'stilbenedisulfonic acid disodium salt. This particular brightener species is commercially marketed under the tradenarne Tinopal 5BM-GX by Ciba-Geigy Corporation.

When in the above formula, RI is anilino, R2 is morphilino and M is a cation such as sodium, the brightener is 4,4'-bis[(4-anilino-6-morphilino-s-triazine-2- yl)amino]2,2 stilbenedisulfonic acid, sodium salt. This particular brightener species is commercially marketed under the tradename Tinopal AMS-GX by Ciba Geigy Corporation.

Cationic fabric softenine agents Cationic fabric softening agents can also be incorporated into compositions in accordance with the present invention. Suitable cationic fabric softening agents include the water insoluble tertiary amines or dilong chain amide materials as disclosed in GB-A-1 514 276 and EP-B-0 011 340.

43 Cationic fabric softening agents are typically incorporated at total levels of from 0.5% to 15% by weight, normally from 1% to 5% by weight.

Other optional ingredients Other optional ingredients suitable for inclusion in the compositions of the invention include perfumes, colours and filler salts, with sodium sulfate being a preferred filler salt.

pH of the compositions The present compositions preferably have a pH measured as a 1 % solution in distilled water of at least 9.0, preferably from 10.0 to 12.5, most preferably from 10.5 to 12.0.

Form of the com[Lositions The compositions in accordance with the invention can take a variety of physical forms including granular, tablet bar and liquid forms. The compositions are particularly the so-called concentrated granular detergent compositions adapted to be added to a washing machine by means of a dispensing device placed in the machine drum With the soiled fabric load.

The mean particle size of the components of granular compositions in accordance with the invention should preferably be such that no more that 5% of particles are greater than 1.7mm in diameter and not more than 5% of particles are less than 0. 15 mm in diameter.

44 Laundry washing method Machine laundry methods herein typically comprise treating soiled laundry with an aqueous wash solution in a washing machine having dissolved or dispensed therein an effective amount of a machine laundry detergent composition in accord with the invention. By an effective amount of the detergent composition it is meant from 40g to 300g of product dissolved or dispersed in a wash solution of volume from 5 to 65 litres, as are typical product dosages and wash solution volumes commonly employed in conventional machine laundry methods.

In a preferred use aspect a dispensing device is employed in the washing method. The dispensing device is charged with the detergent product, and is used to introduce the product directly into the drum of the washing machine before the commencement of the wash cycle. Its volume capacity should be such as to be able to contain sufficient detergent product as would normally be used in the washing method.

Once the washing machine has been loaded with laundry the dispensing device containing the detergent product is placed inside the drum. At the commencement of the wash cycle of the washing machine water is introduced into the drum and the drum periodically rotates. The design of the dispensing device should be such that it permits containment of the dry detergent product but then allows release of this product during the wash cycle in response to its agitation as the drum rotates and also as a result of its contact with the wash water.

To allow for release of the detergent product during the wash the device may possess a number of openings through which the product may pass. Alternatively, the device may be made of a material which is permeable to liquid but impermeable to the solid product. which will allow release of dissolved product. Preferably, the detergent product will be rapidly released at the start of the wash cycle thereby providing transient localised high concentrations of product in the drum of the washing machine at this stage of the wash cycle.

Preferred dispensing devices are reusable and are designed in such a way that container integrity is maintained in both the dry state and during the wash cycle. Especially preferred dispensing devices for use with the composition of the invention have been described in the following patents; GB-B-2, 157, 717, GB-B-2, 157, 718, EP-A-0201376, EP-A-0288345 and EPA0288346. An article by J.131and published in Manufacturing Chemist, November 1989, pages 41-46 also describes especially preferred dispensing devices for use with granular laundry products which are of a type commonly know as the "granulette". Another preferred dispensing device for use with the compositions of this invention 10 is disclosed in PCT Patent Application No. W094/11562. Especially preferred dispensing devices are disclosed in European Patent Application Publication Nos. 0343069 & 0343070. The latter Application discloses a device comprising a flexible sheath in the form of a bag extending from a support ring defining an orifice, the orifice being adapted to admit to the bag sufficient product for one washing cycle in a washing process. A portion of the washing medium flows through the orifice into the bag, dissolves the product, and the solution then passes outwardly through the orifice into the washing medium. The support ring is provided with a masking arrangerrint to prevent egress of wetted, undissolved, product, this arrangement typically comprising radially extending walls extending from a central boss in a spoked wheel configuration, or a similar structure in which the walls have a helical form.

Alternatively, the dispensing device may be a flexible container, such as a bag or pouch. The bag may be of fibrous construction coated with a water impermeable protective material so as to retain the contents, such as is disclosed in European published Patent Application No. 00 18678. Alternatively it may be formed of a water-insoluble synthetic polymeric material provided with an edge seal or closure designed to rupture in aqueous media as disclosed in European published Patent Application Nos. 0011500, 0011501, 0011502, and 0011968. A convenient form of 46 water fi-angible closure comprises a water soluble adhesive disposed along and sealing one edge of a pouch formed of a water impermeable polymeric film such as polyethylene or polypropylene.

PackIging for the cornj22sitions Commercially marketed executions of the bleaching compositions can be packaged in any suitable container including those constructed from paper, cardboard, plastic materials and any suitable laminates. A preferred packaging execution is described in European Application No. 94921505.7.

47 ExMples Abbreviations used in ExMples In the detergent compositions, the abbreviated component identifications have the following meanings:

LAS C45E7 Betaine Dianionic CAT Sodium linear C 12 alkyl benzene sulfonate A C14-15 predominantly linear primary alcohol condensed with an average of 7 moles of ethylene oxide A C12-14 Betaine available form Albright & Wilson and sold under the tradename empigen BB. Disodium. salt of alpha sulpholauric acid R2.N+ (CH3)3 with R2 C 12 - C 14 In the following Example all levels are quoted as % by weight of the surfactant 20 system:

Component weight % C45E7 19 Betaine 12 CAT 17 LAS II Dianionic 350 48

Claims (6)

Claims

1. A detergent composition comprising a surfactant system comprising a net zero charge (NZC) surfactant and a dianionic surfactant wherein the dianionic surfactant comprises a terminally located anionic group and wherein the equivalent weight of the dianionic surfactant salt is less than 200.

2. A detergent composition according to claim 1 wherein the surfactant system additionally comprises an anionic or cationic surfactant at a level of less than 15% by 10 weight of the surfactant system.

3 3. A detergent composition according to either of the preceding claims wherein the weight ratio of NW surfactant to dianionic surfactant is from 1: 1 to 10: 1 -

4. A detergent composition according to any of the preceding claims wherein the NZC surfactant is selected from the group consisting of. (1) a mixture of cationic and anionic surfactants present at a 1: 1 charge ratio; (ii) nonionic surfactant; (iii) zwitterionic surfactant; and (iv) amphotenc surfactant or mixtures thereof.

5. A detergent composition according to any of the preceding claims wherein the equivalent weight of the dianionic surfactant is less than 140.

6. A detergent composition according to any of the preceding claims wherein the dianionic surfactant is selected from either an alkyl ccsulpho carboxylate surfactant or an alkyl disulphate surfactant or mixtures thereof.