Stably suspended organic peroxy bleach in a structured aqueous liquid

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BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a structured aqueous based heavy duty liquid detergent formulation containing a suspended bleach along with selected stability enhancers.

Liquid detergent products have become a large segment of the U.S. detergent market. Their market share in the past several years has more than doubled. Currently marketed liquid detergents contain built-in softening in the wash as well as enzymes for added stain removal. No completely formulated liquid detergents however, contain a completely satisfactory bleach.

Liquid bleach adjuncts which are to be added separately to the wash, containing hypochlorite or hydrogen peroxide are established, successful products. A low pH, surfactant-structured liquid containing 1,12 diperoxydodecanedioic acid (DPDA), has been patented by Humphreys et al. in U.S. Pat. No. 4,642,198. A structured aqueous system has been employed in this bleach adjunct but due to the low pH and low amount of surfactant usually employed, the adjunct product cannot be used alone to accomplish washing.

The high concentrations of surfactants which must be included in a fully formulated liquid detergent to clean during the wash generally make it difficult to prepare an appropriately structured liquid. Structuring, however, is necessary to suspend the particulate bleach and, thus, minimize settling and other types of instability. Structured liquids are well known in the art and are described more fully below. Further, the large amount of surfactant required usually increases the viscosity of structured liquids to unacceptable levels. The viscosity, thus, must be decreased to a commercially acceptable level while still retaining the suspending characteristics of the structured liquid.

An additional difficulty is that the suspended bleach particles must not be too soluble in the product or the bleach may react with included organic materials. It is, thus, desirable to further stabilize the bleach by decreasing the pH of the concentrated composition to decrease the solubility of the bleach particles. A low pH, however, is not optimal for washing and, thus, it must be capable of increasing substantially on dilution when the product is used so that normal alkaline wash pH's can prevail.

It was, thus, desireable to formulate an aqueous based heavy duty detergent which contains relatively stable bleach and high levels of surfactant, yet still retains the suspending properties of a structured liquid while incorporating acceptable viscosity characteristics.

2. Description of the Art

One of the early patents is Edwards et al U.S. Pat. No. 3,996,152, disclosing the suspension of diperoxyacids by non-starch thickening agents such as Carbopol 940 in an aqueous media at low pH. Suitable actives were diperazelaic, diperbrassylic, dipersebacic and diperisophthalic acids. Bradley U.S. Pat. No. 4,017,412 reports similar systems except that starch based thickening agents were employed. From later investigations it became evident that the thickener types mentioned in the foregoing patents formed gel-like matrices which exhibited instability upon storage at elevated temperatures. At high concentrations they cause difficulties with high viscosity.

U.S. Patent 4,642,198 (Humphreys et al.) hereby incorporated by reference herein, lists a variety of water-insoluble organic peroxy acids intended for suspension in an aqueous, low pH liquid. This patent disclosed the use of surfactants, both anionic and nonionic, as suspending agents for the peroxy acid particles. The preferred peroxy material was 1,12-diperoxydodecanedioic acid (DPDA).

This art has emphasized optimizing the suspending or thickening chemical components of the liquid bleach to improve physical stability.

EP No. 176,124 to de Jong and Torenbeck discloses a pourable bleach composition containing peroxycarboxylic acid in an aqueous suspension with 0.5 to 15% alkylbenzene sulfonic acid and low levels of sulfate salt.

Neither of the above patents discloses the use of a system which will allow the compositions to be used as effective heavy duty liquid detergents in the main wash. Both compositions must be used with a buffered adjunct (powder or liquid) to ensure the neutral to alkaline pH necessary for general detergency. The decline in detergency with reduced pH is well known in the art and is discussed in Cockrell, U.S. Pat. No. 4,259,201. deJong avoids high surfactant concentrations. Such compositions are said to be excessively thick and difficult to pour. Humphreys claims surfactant concentrations from 2-50%; however, compositions in excess of about 15% may exhibit excessive thickness and Humphrey's pH is too low for commercially acceptable detergency.

There have been many different approaches to the problem of producing an aqueous based heavy duty liquid detergent containing a bleach; however, none of these approaches have been completely satisfactory. In many cases stability has been enhanced at the expense of acceptable viscosity or a low pH has been employed to improve bleach stability by sacrificing alkaline wash pH's.

Accordingly, it is an object of the present invention to provide a fully formulated aqueous based heavy duty liquid detergent composition containing a suspended peroxy bleach. The composition exhibits good stability, acceptable viscosity and good bleaching and cleaning characteristics while substantially eliminating or minimizing many of the problems of the art. Other objects and advantages will appear as the description proceeds.

SUMMARY OF THE INVENTION The attainment of the above objects is made possible by this invention which includes an aqueous based liquid cleaning composition containing generally the following components:

(1) 1 to 40% by weight of a solid, particulate, substantially water-insoluble organic peroxy acid;

(2) about 10 to 50% by weight of a surfactant;

(3) about 1 to 40% by weight of a pH adjusting "jump" system including:

(a) a borate;

(b) a polyol, and having a polyol to borate ratio of 1:1 to 10:1; and

(4) about 0.1 to 5% of a stability enhancing polymer which is a copolymer of a hydrophilic and a hydrophobic monomer, the hydrophilic monomer selected from the group of the acid or salt derivatives of maleic anhydride, acrylic acid, methacrylic acid, as well as analogues where the carboxylate group is replaced by other anionic moieties such as sulfonate, sulfate phosphonate and the like as well as mixtures thereof, the hydrophobic monomer being either a hydrophilic monomer functionalized with a hydrophobic moiety selected from the group of fatty amides fatty esters, fatty alkoxylates, C.sub.8-22 alkyls, fatty alkylaryls and mixtures thereof or a pendant alkyl group such as that formed by reaction of a C.sub.8-22 a olefin.

(5) optional viscosity modifiers.

(6) standard detergent ingredients such as fluorescent whiteners, dyes, perfumes, enzymes, and the like.

DETAILED DESCRIPTION OF THE INVENTION

Aqueous structured heavy duty liquids containing a color-safe peroxyacid bleach have been developed. The liquids generally contain 10-50% surfactant, 1-40% of a "pH jump" system for providing a suitable pH environment in both the concentrated product and on dilution in the wash, 1-40% of an insoluble organic peroxyacid bleach, 0.10-2.0% sequestering agent to minimize transition-metal catalyzed bleach decomposition, 0-10% viscosity reducing agents such as excess inorganic salts, v polyacrylates, and polyethylene glycols; and, 0.10-2.0% or more of a "physical stability enhancing agent" or "decoupling" agent or "deflocculating" agent which increases the robustness of an otherwise physically metastable system. Additional ingredients can include builders, fluorescer, enzymes, perfume, antiredeposition aids, dye and the like.

BLEACHES

Peroxyacids usable in this invention are solid and substantially water insoluble compounds. One of the peroxyacids utilized has been 1,12 diperoxydodecanedioic acid (DPDA). More preferred peracids include 4,4'-sulfonylbisperoxybenzoic acid (SBPB, ex. Monsanto) and 1,14 diperoxytetradecanoic acid (DPTA). In general, the organic peroxyacids can contain one or two peroxy groups and can be either aliphatic or aromatic. Examples include alkylperoxy acids, alkenylperoxy acids and arylperoxy acids such as peroxybenzoic acid; aliphatic monoperoxyacids such as peroxylauric and peroxystearic acids; diperoxy acids including alkyldiperoxy acids, alkenyldiperoxy acids and aryldiperoxy acids such as 1,9-diperoxyazelaic acids, diperoxybrassylic acid, diperoxysebacic acid and diperoxyisophthalic acid.

Alternative bleaching agents also include phthaloyl amino-peroxocaproic acids "PAP", a new biodegradable, safe, high-melting peracid molecule available from Hoechst. ##STR1## This peracid is believed to be soluble only in an alkaline-pH range.

The bleaching compounds will be present in an effective amount and will generally be a solid, particulate, substantially water-insoluble organic peroxy acid stably suspended in the composition. The compositions will have an acid pH in the

range of from 1 to 6.5, preferably from 2 to 5.

The particle size of the peroxy acid used in the present invention is not crucial and can be from about 1 to 2000 microns although a small particle size is favoured for laundering application.

The composition of the invention may contain from about 1 to 40% by weight of the peroxy acid, preferably from 1 to about 10 by weight.

DEFLOCCULATING POLYMERS

The second essential component is a stability enhancing polymer which is a copolymer of hydrophilic and hydrophobic monomers. Suitable polymers are obtained by copolymerizing maleic anhydride, acrylic or methacrylic acid or other hydrophilic monomers such as ethylene or styrene sulfonates and the like with similar monomers that have been functionalized with hydrophobic groups. These include the amides, esters, ethers of fatty alcohol or fatty alcohol exthoxylates.

In addition to the fatty alcohols and ethoxylates, other hydrophobic groups such as olefins or alkylaryl radicals may be used. What is essential is that the copolymer have acceptable oxidation stability and that the copolymer have hydrophobic groups that interact with the lamellar droplets and hydrophilic groups of the structured liquid to prevent flocculation of these droplets and thereby prevent physical instability and product separation. In practice, a copolymer of acrylic acid and lauryl methacrylate (M.W. 3800) has been found to be effective at levels of 0.5 to 1%.

These materials are more fully described in a companion case to Montague and Van de Pas Serial Number 365,080 filed concurrently herewith and incorporated herein by reference.

In addition to the compounds mentioned above, and as more fully set out in the Montague et al. application, the compositions according to the invention may contain one, or a mixture of deflocculating or decoupling polymer types. The term `polymer types` is used because, in practice, nearly all polymer samples will have a spectrum of structures and molecular weights and often impurities. Thus, any structure of deflocculation polymers described in this specification refers to polymers which are believed to be effective for deflocculation purposes as defined above. In practice, these effective polymers may constitute only part of the polymer sample, provided that the amount of deflocculation polymer in total is sufficient to effect the desired deflocculation. Furthermore, any structure described herein for an individual polymer type refers to the structure of the predominating deflocculating polymer species and the molecular weight specified is the weight average molecular weight of the deflocculation polymers in the polymer mixture.

The hydrophilic backbone of the polymer generally is a linear, branched or lightly crosslinked molecular composition containing one or more types of relatively hydrophilic monomer units. Preferably the hydrophilic monomers are sufficiently water soluble to form at least a 1% by weight solution when dissolved in water. The only limitations to the structure of the hydrophilic backbone are that the polymer must be suitable for incorporation in an active-structured aqueous liquid detergent composition and that a polymer corresponding to the hydrophilic backbone made from the backbone monomeric constituents is relatively soluble in water. The solubility in water at ambient temperature and at a pH of 3.0 to 12.5 is preferably more than 1 g/l, more preferably more than 5 g/l, and most preferred more than 10g/l.

Preferably the hydrophilic backbone is predominantly linear; 1more preferably the main chain of the backbone constitutes at least 50% by weight, preferably more than 75%, most preferred more than 90% by weight of the backbone.

The hydrophilic backbone is composed of monomer units, which can be selected from a variety of units available for the preparation of polymers. The polymers can be linked by any possible chemical link, although the following types of linkages are preferred: ##STR2##

Examples of types of monomer units are: (i) Unsaturated C.sub.1-6 acids, ethers, alcohols, aldehydes, ketones, or esters. Preferably these monomer units are mono-unsaturated. Examples of suitable monomers are acrylic acid, methacrylic acid, maleic acid, crotonic acid, itaconic acid, aconitic acid, citraconic acid, vinyl-methyl ether, vinyl sulphonate, vinyl alcohol obtained by the hydrolysis of vinyl acetate, acrolein, allyl alcohol and vinyl acetic acid.

(ii) Cyclic units, either unsaturated or comprising other groups capable of forming inter-monomer linkages. In linking these monomers the ring-structure of the monomers may either be kept intact, or the ring structure may be disrupted to form the backbone structure. Examples of cyclic monomer units are sugar units, for instance, saccharides and glucosides; alkoxy units such as ethylene oxide and hydroxy propylene oxide; and maleic anhydride.

(iii) Other units, for example, glycerol or other saturated polyalcohols.

Each of the above mentioned monomer units may be substituted with groups such as amino, amine, amide, sulphonate, sulphate, phosphonate, phosphate, hydroxy, carboxyl and oxide groups.

The hydrophilic backbone of the polymer is preferably composed of one or two monomer types but three or more different monomer types in one hydrophilic backbone may be used. Examples of preferred hydrophilic backbones are: homopolymers of acrylic acid, copolymers of acrylic acid and maleic acid, poly 2-hydroxy ethyl acrylate, polysaccharides, cellulose ethers, polyglycerols, polyacrylamides, polyvinylalcohol/polyvinylether copolymers, poly sodium vinyl sulphonate, poly 2-sulphato ethyl methacrylate, polyacrylamido methyl propane sulphonate and copolymers of acrylic acid and tri methyl propane triacrylate.

Optionally the hydrophilic backbone may contain small amounts of relatively hydrophobic units, e.g. those derived from polymers having a solubility of less than 1 g/l in water, provided that the overall solubility of the hydrophilic polymer backbone still satisfies the solubility requirements as specified above. Examples of relatively water insoluble polymers are polyvinyl acetate, polymethyl methacrylate, polyethyl acrylate, polyethylene, polypropylene, polystryrene, polybutylene oxide, propylene oxide and polyhdroxy propyl acetate.

Preferably the hydrophobic side chains are part of a monomer unit which is incorporated in the polymer by copolymerising hydrophobic monomers and the hydrophilic monomers making up the backbone of the polymer. The hydrophobic side chains for this use preferably include those which when isolated from their linkage are relatively water insoluble, i.e. preferably less than 1 g/l more preferred less than 0.5 g/l, most preferred less than 0.1 g/l of the hydrophobic monomers, will dissolve in water at ambient temperature and a pH of 3.0 to 12 5.

Preferably the hydrophobic moieties are selected from siloxanes, saturated and unsaturated alkyl chains, e.g. having from 5 to 24 carbon atoms, preferably from 6 to 18, most preferred from 8 to 16 carbon atoms, and are optionally bonded to the hydrophilic backbone via an alkoxylene or polyalkoxylene linkage, for example, a polyethoxy, polypropoxy or butyloxy (or mixture of same) linkage having from 1 to 50 alkoxylene groups. Alternatively the hydrophobic side chain may be composed of relatively hydrophobic alkoxy groups, for example, butylene oxide and/or propylene oxide, in the absence of alkyl or aklenyl groups. In some forms, the side-chain(s) will essentially have the character of a nonionic surfactant.

In this context UK patent specifications GB No. 1,506,427 A and Gb No. 1,589,971 A disclose aqueous compositions including a carboxylate polymer partly esterified with nonionic surface active side-chains. The particular polymer described (a partially esterified, neutralized co-polymer of maleic anhydride with vinylmethyl ether, ethylene or stryrene present at from 0.1 to 2% by weight of the total composition) is not completely satisfactory.

Thus, one aspect of the present invention provides a structured liquid detergent composition having a dispersion of lamellar droplets in an aqueous continuous phase, and a deflocculating polymer having a hydrophilic backbone and at least one hydrophobic side-chain.

U.S. Pat. Nos. 3,235,505, 3,238,309, and 3,457,176 describe the use of polymers having relatively hydrophilic backbones an relatively hydrophobic side-chains as stabilizers for emulsions.

Preferably, the deflocculating polymer has a lower specific viscosity than those disclosed in GB No. 1,506,427 A and GB No. 1,589,971 A, i.e. a specific viscosity less than 0.1 measured as 1 g in 100 ml of methylethylketone at 25.degree. C. Specific viscosity is a dimensionless viscosity-related property which is independent of shear rate and is well known in the art of polymer science.

Some polymers having a hydrophilic backbone and hydrophobic side-chains are known for thickening isotropic aqueous liquid detergents, for example, from European Patent Specification EP-A-No. 244,006.

One preferred class of polymers for use in the compositions of the present invention comprises those of general formula (I) ##STR3## wherein: z is 1; (x+y):z is from 4:1 to 1000:1, preferably from 6:1to 250:1; in which the monomer units may be in random order; y preferably being from 0 up to a maximum equal to the value of x; and n is at least 1;

R.sup.1 represents --CO--O--, --O--, --O--CO--, --CH.sub.2 --, --CO--NH--or is absent;

R.sup.2 represents from 1 to 50 independently selected alkyleneoxy groups preferably ethylene oxide or propylene oxide groups, or is absent, provided that when R.sup.3 is absent and R.sup.4 represents hydrogen or contains no more than 4 carbon atoms, then R.sup.2 must contain an alkyleneoxy group with at least 3 carbon atoms;

R.sup.3 represents a phenylene linkage, or is absent;

R.sup.4 represents hydrogen or a C.sub.1-24 alkyl or C.sub.2-24 alkenyl group, with the provisions that

(a) when R.sup.1 represents --O--CO--, R.sup.2 and R.sup.3 must be absent and R.sup.4 must contain at least 5 carbon atoms;

(b) when R.sup.2 is absent, R.sup.4 is not hydrogen and when R.sup.3 is absent, then R.sup.4 must contain at least 5 carbon atoms;

R.sup.5 represents hydrogen or a group of formula --COOA.sup.4;

R.sup.6 represents hydrogen or C.sub.1-4 alkyl; and

A.sup.1, A.sup.2, A.sup.3 and A.sup.4 are independently selected from hydrogen, alkali metals, alkaline earth metals, ammonium and amine bases and C.sub.1-4.

Another class of polymers for use in compositions of the present invention comprise those of formula (II) ##STR4## wherein: Q.sup.2 is a molecular entity of formula (IIa): ##STR5## wherein z and R.sup.1-6 are as defined for formula (I);A.sup.1-4, are as defined for formula (I).

Q.sup.1 is a multifunctional monomer, allowing the branching of the polymer, wherein the monomers of the polymer may be connected to Q.sup.1 in any direction, in any order, therewith possibly resulting in a branched polymer. Preferably Q.sup.1 is trimethyl propane triacrylate (TMPTA), methylene bisacrylamide or divinyl glycol. n and z are as defined above; v is 1; and (x+y+p+q+r):z is from 4:1 to 1,000:1, to 1,000:1, preferably from 6:1 to 250:1; in which the monomer units may be in random order; and preferably either p and q are zero, or r is zero;

R.sup.7 and R.sup.8 represents --CH.sup.3 or -H;

R.sup.9 and R.sup.10 represent substituent groups such as amino, amine, amide, sulphonate, sulphate, phosphonate, phosphate, hydroxy, carboxyl and oxide groups or (C.sub.2 H.sub.4 O).sub.t H, wherein t is from 1-50, and wherein the monomer units may be in random order. Preferably the substituted groups are selected from --SO.sub.3 Na, --CO--O--C.sub.2 H.sub.4--OSO.sub.3 Na, --CO--O--NH--C(CH.sub.3).sub.2 2-SO.sub.3 NA, --CO--NH.sub.2, --O--CO--CH.sub.3, --OH

The above general formulas include those mixed copolymer forms wherein, within a particular polymer molecule where n is 2 or greater, R.sup.-R.sup.12 differ between individual monomer units therein.

Although in the polymers of the above formulas and their salts, the only requirement is that n is at least 1, x (+y+p+q+r) is at least 4 and that they fulfill the definitions of the declocculating effect hereinbefore described (stabilizing and/or viscosity lowering), it is helpful here to indicate some preferred molecular weights. This is preferable to indicating values of n. However, it must be realized that in practice there is no method of determining polymer molecular weights with 100% accuracy.

As already referred to above, only polymers of which the value of n is equal to or more than 1 are believed to be effective as deflocculating polymers. In practice, however, generally a mixture of polymers will be used. For the purpose of the present invention it is not necessary that the polymer mixtures as used have an average value of n which is equal or more than one; also polymer mixtures of lower average n value may be used, provided that an effective amount of the polymer molecules have one or more n-groups. Dependant on the type and amount of polymer used, the amount of effective polymer as calculated on the basis of the total polymer fraction may be relatively low, for example, samples having an average n-value of abouve 0.1 have been found to be effective as deflocculation polymers.

Gel permeation chromatography (GPC) is widely used to measure the molecular weight distribution of water-soluble polymers. By this method, a calibration is constructed from polymer standards of known molecular weight and a sample of unknown molecular weight distribution is compared with this.

When the sample and standards are of the same chemical composition, the approximate true molecular weight of the sample can be calculated, but if such standards are not available, it is common practice to use some other well characterized standards as a reference. The molecular weight obtained by such means is not the absolute value, but is useful for comparative purposes. Sometimes it will be less than that resulting from a theoretical calculation for a dimer.

It is possible that when the same sample is measured, relative to different sets of standards, different molecular weights can be obtained. This is the case when using e.g. polyethylene glycol, polyacrylate and polystryrene sulphonate standards. For the compositions of the present invention exemplified hereinbelow, the molecular weight is specified by reference to the appropriate GPC standard.

For the polymers of formulae I and II and their salts, it is preferred to have a weight average molecular weight in the region of from 500 to 5000,000, preferably from 750 to 1000,000 most preferably from 1,000 to 30,000, especially from 2,000 to 10,000 when measured by GPC using polyacrylate standards. For the purposes of this definition, the molecular weights of the standards are measured by the absolute intrinsic viscosity method described by Noda, Tsoge and Nagasawa in Journal of Physical Chemistry, volume 74, (1970), pages 710-719.

In particular, the stability enhancing decoupling or deflocculating polymers are included in an amount of about 0.1 to and are copolymers of a hydrophilic and a hydrophobic monomer. The hydrophilic monomer is preferably the acid or salt derivatives of maleic anhydride acrylic acid, methacrylic acid, and mixtures of these, the hydrophobic monomer is a hydrophilic monomer functionalized with a hydrophobic moiety which is preferably a fatty amide, fatty ester, fatty alkoxylate, C8-C22 alkyl, alkylaryl, and mixtures of these.

Some specific examples are as follows:

______________________________________ Sample/No. Composition (Molar) Viscosity, cps. ______________________________________ 1 25:1 (100 AA)LMA 3800 2 25:1 (95:5 AA:SVS)LMA 520 3 25:1 (90:10 AA:SVS)LMA 500 4 25:1 (95:5 AA:HEMA-S)LMA 640 5 25:1 (90:10 AA:HEMA-S)LMA 950 6 25:1 (95:% AA:AMPS)LMA 9500 7 95:1 (90:10 AA:AMPS)LMA 600 ______________________________________ Abbreviations: SVS sodium vinyl sulfonate HEMAS 2sulphato ethyl methacrylate AMPS acrylamido methyl propane sulphonic acid LMA lauryl methacrylate AA acrylic acid

STRUCTURING SYSTEM--SURFACTANT

A third critical element of this invention is a surfactant structuring system. Structured surfactant combinations can include LAS/ethoxylated alcohol, LAS/lauryl ether sulfate (LES) LAS/LES/ethoxylated alcohol, amine oxide/SDS, cocoanut diethanolamide/LAS, and other combinations yielding lamellar phase liquids in the presence of pH jump components and other electrolytes at acidic pH's. Other anionic detergents such as secondary alkane sulfonates can be used in place of linear alkylbenzene sulfonate (LAS). These structured surfactant systems are necessary to suspend the insoluble peroxyacid crystals and thereby avoid undesirable settling on storage. Structuring and/or viscosity reducing salts can include sodium sulfate, sodium citrate, sodium phosphate and the like.

Aqueous surfactant structured liquids are capable of suspending solid particles without the need of other thickening agent and can be obtained by using a single surfactant or mixtures of surfactants in combination with an electrolyte. The liquid so structured contains lamellar droplets in a continuous aqueous phase.

The preparation of surfactant-based suspending liquids is known in the art and normally requires a nonionic and/or an anionic surfactant and an electrolyte, though other types of surfactant or surfactant mixtures, such as the cationics and zwitterionics, can also be used. Indeed, various surfactants or surfactant pairs or mixtures can be used in combination with several different electrolytes, but it should be appreciated that electrolytes which would easily be oxidized by peroxy acids, such as chlorides, bromides and iodides, and those which are not compatible with the desired acid pH range, e.g. carbonates and bicarbonates, should preferably be excluded from the peroxy acid suspending surfactant liquid compositions of the invention.

Examples of different surfactant/electrolyte combinations suitable for preparing the peroxy acid suspending surfactant structured liquids are:

(a) surfactants:

(i) cocoanut diethanolamide/alkylbenzene sulphonate

(ii) C.sub.9 -C.sub.16 alcohol ethoxylate/alkylbenzene sulphonate;

(iii) lauryl ethersulphate/alkylbenzene sulphonate;

(iv) alcohol ether sulphate; in combination with:

(v) secondaryl alkane sulfonates/alcohol ethoxylates

(vi) alkyl ether sulfonates/alkylbenzene sulfonates/alcohol ethoxylates

(b) electrolytes:

(i) sodium sulphate and/or

(ii) sodium nitrate.

The surfactant structured liquids capable of suspending the peroxy acid include both the relatively low apparent viscosity, lamellar phase surfactant structured liquids and the higher apparent viscosity surfactant liquids with structuring resulting from other phase types, e.g. hexagonal phase, the viscosity of which may be in the range of from about 50 to 20,000 centipoises (0.05 to 20 Pascal seconds) measured at a shear rate of 21 second.sup.-1 at 25.degree. C.

Accordingly, aqueous liquid products having a viscosity in the above range are encompassed by the invention, though in most cases products having a viscosity of about 0.2 PaS, measured at 21.sup.-1, particularly from 0.25 to 12 paS, are preferred.

Although the primary objective of the present invention is to provide a stable pero