GB2163175A - Bleaching and laundering composition - Google Patents

Description

1

SPECIFICATION

Bleaching and laundering composition The present invention relates, in genera 1, to bleaching detergent compositions as a bleaching agent a peroxygen compound in combination with an organic activatortherefor, and the application of such compositions to laundering operations. More particularly, the present invention relates to granular bleaching detergent compositions which provide enhanced bleaching performance concomitantwith a significant improvement in the stability of the peroxyacid bleaching species in the wash solution.

Bleaching compositions which release active ox- ygen in the wash solution are extensively described in the prior art and commonly used in laundering operations. In general, such bleaching compositions contain peroxygen compounds, such as, perborates, percarbonates, perphosphates and the like which promote the bleaching activity byforming hydrogen peroxide in aqueous solution. A major drawback attendaritto the use of such peroxygen compounds is thatthey are not optimally effective att he relatively lowwas - hing temperatures employed in most house- holdwashing machines in the United States, i.e. temperatures in the range of 80oto 130'F (27to 54C). Byway of comparison, European wash temperatures are generally substantially higher extending over a range, typically,from Wto 200'F (32'to 9WC).

However, even in Europe and those other countries which generally presently employ near boiling washing temperatures, there is a trend towards lower temperatu re laundering.

In an effortto enhancethe bleaching activity of peroxygen bleaches,the prior art has employed materials called activators in combination with the peroxygen compound. It is generally believed thatthe interaction of the peroxygen compound and the activator results in theformation of a peroxyacid which is a more active bleaching species than hydrogen peroxide at lower temperatures. Numerous compounds have been proposed in the art as activatorsfor peroxyden bleachings among which are included carboxylic acid anhydrides such as those disclosed in U.S. Patents Nos. 3,298,775,3,338,839, and 3,532,634; carboxylic esters such as those disclosed in U.S. Patent No. 2,995,905; N- acyl compounds such asthose described in U.S. Patents Nos. 3 ' 912,648 and 3,919,102; cyanoamines such as de- scribed in U.S. Patent No. 4,199,466; and acyl sulphoamides such as disclosed in U.S. Patent No. 3,245,913.

Theformation and stability of the peroxyacid bleaching species in bleach systems containing a peroxygen compound and an organic activator has been recognized as a problem in the prior art. U.S. Patent No. 4,255,452 to Leigh, forexample, specifically addresses itself to the problem of avoiding the reaction of peroxyacid with peroxygen compound to form whatthe patent characterizes as -useless products, viz. the corresponding carboxylic acid, molecular oxygen and water". The patentstates that GB 2 163 175 A 1 such side-reaction is "doubly deleterious since peracid and percompound... are destroyed simul- taneously." The patentee thereafter describes certain polyphosphonic acid compounds as chelating agents which are said to inhibitthe above- described peroxyacid-consumed side reaction and provide an improved bleaching effect. In contrast with the use of these chelating agents, such as, ethylene diamine tetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) are substantially ineffective and do not provide improved bleaching effects. Accordingly, a disadvantage of the bleaching compositions of the Leigh patent is thatthey necessarily preclude the use of conventional sequestrants, many of which are less expensive and more readily available than the disclosed polyphosphonic acid compounds.

The influence of silicates on the decompostion of peroxyacid in the wash andlor bleaching solution has heretofore gone unrecognized in the art. U.S. Patents Nos.3,860,391 and 4,292,575 disclose that silicates are conventionally employed as additives to peroxidecontaining bleaching solutions forthe purpose of stablizing peroxide compounds therein. However,the patentees note the fact that the use of silicates in such bleaching solutions maycreate other problems in the bleaching operations, such as,theformation of silicate precipitates which deposit onthe bleached goods. Consequently, the patents are directed to processes for bleaching cellulosefibres with silicatefree bleaching solutions in which peroxide stability is enhanced with compounds otherthan silicates.

European Patent Publication No. 0,028,432, pub- lished May 13,1981, discloses a granular laundry composition containing, among otherthings, a waterinsoluble silicate and an organic activator compound for a peroxygen bleach. The pH characteristics of such laundry composition are said to be critical; specifical- ly,the pH in a 2% aqueous dispersion isfrom 2 to 9, and preferablyfrom 4to 7. At page 7 of the Publication there are described certain polyphosphonic acid compounds as being highly preferred components of the composition, the publication stating in this regard that the po lyphosphonates "have been found to be uniquely effective in stabilizing organic peroxyacids againstthe generally deleterious effect of waterinsoluble silicates, especiallythose belonging to the zeolite and kaolin classes---. The nature of such "deleterious effect" is notspecified. At page 38 of the Publication granular laundry compositions are disclosed in Examples VIII to X which do not contain sodium silicate, all of such compositions being shown to contain Dequest 2041 (ethyl enediamine tet- ramethylene phosphonic acid). (The word "Dequest" is a trade mark.) The compositions of the aforementioned examples also contain a peroxygen compound activatorwhich is incorporated into agglomerate particles consisting of the activator, a water-insoluble silicate compound and a nonionic surfactant.

Accordingly, the art has heretofore failed to appreciate orsuggestthe improved bleaching performance which can be achieved with particulate bleaching detergent compositions containing a peroxyacid corn- Formulae in the printed specification were reproduced from drawings submitted after the date of filing, in accordance with Rule 20(14) of the Patents Rules 1982.

-2 pound when such compositions are characterised by the absence of water-soluble silicate compounds.

The present invention broadly provides a bleaching detergent composition comprising a bleaching agent comprising a peroxyacid compound and/or a water soluble saitthereof and a surface active agent, the composition being substantiallyfree of (i) water soluble silicate compounds, (ii) organic activators for peroxygen compounds,and (iii) agglomerate parti cles which essentially comprise a mixture of an activator, a water-insoluble silicate compound and a nonionicsurfactant.

The present invention will thus be understood to encompass a particulate bleaching detergentcom position comprising: (a) a bleaching agentcomprising 80 a peroxyacid compound andlorawater-soluble salt thereof; and (b) atleastone surface active agentwhich isan anionic, cationic, nonionic, ampholyticorzwitter ionledetergent; the bleaching detergent composition being substantial ly free of (i) water-soluble silicate 85 compounds; (ii) organic activatorsfor peroxygen compounds; and (iii) agglomerate particleswhich essential [y comprise an activator, awater-insoiuble silicate compound and a nonlonicsurfactant.

In accordance with the process of the invention, 90 bleaching of stained andlor soiled materials is - effected by contacting such materials with an aqueous solution of the above-defined bleaching detergent composition.

The present invention is predicated on the discovery 95 thatthe undesired loss of peroxyacid in the aqueous wash solution by reaction of peroxyacid with hydrogen peroxide ora peroxygen compound (or more specifically in the latter case, hydrogen peroxide formed from such a peroxygen compound) to form molecularoxygen is markedly reduced in bleaching systems which are substantially free of water-soluble silicate compounds. Although the applicants do not Wish to be bound to any particulartheory of operation it isbelieved thatthe presence of water-soluble silicates in bleaching. systems containing a peroxyacid compound catalyzesthe aforementioned reaction of peroxyacid with hydrogen peroxide which results in the loss of active oxygen from the wash solution which would otherwise be available for bleaching. It 110 has been recognized in the artthat metal ions, such as, for example. ions of iron and copper serve-to catalyze the decomposition of hydrogen peroxide and also the peroxyacid reaction with hydrogen peroxide. Howev- er, with regard to such metal ion catalysis. the applicants have surprisingly discovered that conventional sequestrants, such as EDTA or NTA, which the prior art has deemed to be ineffectivefor inhibiting the aforementioned peroxyacidconsuming reaction (see, for exam plethe statement in column 4 of U.S. Patent 120 4,225,452) can be incorporated into the compositions of the present invention to stabilize the peroxyacid in solution. -

The term "water-soluble silicate compounds" refers to compounds such as sodium silicate which are substantially soluble in aqueous laundering solutions and commonly present in conventional bleaching detergentcompositions, but are substantially eliminated in the compositions of the present invention. The present invention contemplates, however, incorporat- 130 GB 2 163 175 A 2 !rig substantially water-insoluble silicates, most notably, alumino- silicate materials such as clays and zeolites into the bleaching detergent compositions described herein, water-soluble silicate compounds being considered far more detrimental to peroxyacid stabilitythan water- insoluble materials such as alumino-silicates.

In a preferred embodiment of the invention, the bleaching compositions described herein additionally contain a sequestering ageritto enhancethe stability of the peroxyacid bleaching compound in solution by inhibiting its reaction with hydrogen peroxide in the presence of metal ions. The term "sequestering agent" as used herein refers to organic compounds Which are able to form a co m- plexwith CU21 ionssuch thatthe stability constant (pK) of the complexation Is equal to or greaterthan 6 in water at 250C at an ionic strength of 0.1 molellitre, pK being conventionally defined bythe formula: pK = -log K wherein K represents the equilibrium constant. ThusJor example, the pK values for complexation of copper ion with NTA and EDTA at the stated conditions are 12.7 and 18.8, respectively. The term "sequestering agent" is therefore used herein in a sufficiently restrictive sense to exclude inorganic compounds commonly used in detergent fo rmu lations as builder salts. Especially useful sequestering agents include EDTA, diethylene triamine pentaacetic acid (DEPTA) andthe various phosphonate sequestrants marketed by Monsanto Company under the trademark Dequest, e.g. Dequest 2000,2006,2041,2051 and 2060.

In accordance-with a preferred embodimentof the invention, the described bleaching compositions are further distinguished from certain watersoluble sili- cate free compositions disclosed in the art by restrict ing the use of sequestering agents in the present bleaching compositions to those having a stability constant no greaterthan about20for CU21 complex formation inwaterat250C and atan ionicstrength of 0.1 molellitre.This limitation preferably precludesthe presence of polyphosphonic acid compounds such as Dequest 2041 (ethylene diamine tetramethylene phosphonic acid) a rid Dequest 2060 (diethylene triamine pentamethylene phosphonic acid) in the bleaching compositions ofthe invention; the aforementioned sequestrants having stability constants above about 20. Accordingly, suitable sequestering agents forthis embodiment of the invention include the sodium salts of nitrilotriacetic acid (NTA); ethylene diaminetetracetic acid (EDTA); ethylene diamine; tetramine, i.e. N - (Ch2-CH2 - - NHA3; bis(aminoethyl) glycolether NNN'N'-tetraacetic acid (EGTA); and N(CH2-PO3H2)3 which ismarketed under the tradena me Dequest2000.

EDTA and the aforementioned Dequest2000 are especially preferred for use in this embodiment of the invention.

Thebleaching detergent compositions of the invention are substantially free of water-soluble silicate compoundsand comprisetwo essential components:

(a) a bleaching agent; and (b) a detergent surface active agent.

The bleaching agent useful in such compositions comprises a water-soluble peroxyacid compound andlor a water-soluble saitthereof. Peroxyacid compounds are characterized bythe following general 3 GB 2 163 175 A 3 formula:

0 11 D HOO-C-13-Z wherein R is an alkylene group containing from 1 to about 20 carbon atoms, or a phenylene group, and Z is one or more hydrogen, halogen, aiky], aryl andlor anionicgroups.

The organic peroxyacids and the salts thereof can contain from about 1 to about4, preferably 1 or 2, peroxy groups and can be aliphatic or aromatic. The preferred aliphatic peroxyacids include diperoxyaze- laic acid, diperoxydodecanedioic acid and monoperoxysuccinic acid. Among the aromatic peroxyacid compounds useful herein, monoperoxyphthalic acid (MPPA), particularlythe magnesium salt thereof (MIVIPP), and diperoxyterephthalic acid are especially preferred. A detailed description of the production of MPPA and its magnesium salt is set forth on pages 7-10, inclusive, of EP-A- 0027693, published April 29,1981, the aforementioned pages 7-10 being incorporated herein by reference.

MPPA is produced conveniently by reaction between hydrogen peroxide and phthalic anhydride which can then be employed to produce IVIMPIP by partial neutralisation with magnesium in the presence of a non-reactive organic solvent, the solvent and the relative amounts of the reagents and the solvent preferably being so selected thatthe liquid phase remains as a single phase and thusthe liquid components do not separate to form an emulsion. By the term 'non- reactive'it is meant that solvent does not reactto any marked extentwith hydrogen peroxide orthe intermediate product (MPPA) orthe final product (MIVIPP) underthe prevailing reaction conditions i.e. during the period of timewhilstthe solvent remains in contact with a peroxy-com pound.

It is reported in EP-A-0027693 that one suitable class of 105 organic solvents comprises low molecular weight aliphatic esters. As a general guide, such esters can contain from 3to 10 carbon atoms in total and are, preferably, acetates, especially ethyl acetate, or prop- ionates orformates.

The hydrogen peroxide is employed in theform of an aqueous solution. It is reported thatthe presence of an amount of water comparable with the amount of hydrogen peroxide results in formation, in reasonable yield, of product in the reaction mixture. Whilst use of excesswater leads to a particulate product having a lower active-oxygen content and thus a lower conversion of phthalic anhydride to MMPP, it is said that in insufficient water is present the yield of MIVIPP drops substantially.

Analysis of solid MMPP demonstrated that IVIMPIP as formed underthe process conditions described in EP-A-0027693 is hydrated, and thusthe reaction mixture preferably contains sufficient waterfor all the IVIMPIP that is formed to be hydrated and precipitated 125 out of solution. In general, it is preferred to use hydrogen peroxide and water in amounts equivalent to a 40to 60% w/w aqueous hydrogen peroxide, or in the form of a solution having aconcentration in that range already, although some MMPP can be produced 130 where the concentration is somewhat outside the preferred range, but desirably still within the range 30 to 75% w/w hydrogen peroxide. The amount of the aqueous hydrogen peroxide or water and aqueous hydrogen peroxide in total that is employed in practice is often from 50 to 1 00g per litre of organic solvent and where it is desired to minimise the use of solvent, the total amount is preferably within 10% of the maximum permissible whilst retaining a single phase liquid system, and desirablythe amounts of phthalic anhydride and magnesium compound to be used are determined in accordance therewith, also taking into account the following preferred features.

The stoichiometric mole ratio of hydrogen peroxide to phthalic anhydride is 11. It is desirable to employ at leastthe stoichiometric ratio and preferably only a slight excess, i.e. in the range 1.01: 1 to L2: 1, and particularly 1.05:1 to 1.1 2A. Naturally, it is possible to employ mole ratios outside these ranges but still in the range 1:2 to 2: 1, particularly where for example the reaction mixtures are to be recycled. It will be recognised thatwhen the solid phthalic anhydride is introduced, part dissolves and part can remain in solid form, thereby creating a slurry, and therefore it is desirableto maintain stirring to promote good solid/ liquid contact. A convenient amount of anhydride to add is often from 0.6 to 1.5 moles per 1 000g reaction mixture, which in the case of phthalic anhydride is about 96g to about 125g per 10009 final reaction mixture.

Thefinal magnesium compound is preferably present in an amounttheoretically sufficieritto neutralisethe carboxylicacid in all the monoperoxyphthalic acid produced by reaction between the phthalic anhydride and hydrogen peroxide. In orderto achievethis, it is desirableto employ a mole ratio of magnesium compound as Mg to phthalic anhydride (PA) of at least 1:2 and conveniently less than 1A. In more preferred embodiments the Mg: PA mole ratio is in the ran ge 1:2 to 1.2:2, and in many of the preferred embodiments is approximately half the hydrogen peroxide:PA mole ratio. Where the anhydride contains or generates x carboxylate groups per molecule then the ranges are multiplied byxfor example, lx:2 to 1.2x:2. It is highly desirable to employ as the magnesium compound, one that does not introduce anions of strong acids. Compounds thatfulfill that desideratum include magnesium oxide, magnesium hydroxide, magnesium carbonate and basic magne- sium carbonates.

The orderof introduction of the reagents intothe solution can bevaried. Thus,the aqueoushydrogen peroxide can be introduced into a slurry of magnesium compound and phthalic anhydride in the organic solventorthe introduction of the solid reagents can be first. Alternatively all three could be introduced together. However, it is important in any orderof introduction to control thetemperature during the periodthatthe phthalic anhydride and hydrogen peroxide are brought into contact, herein termed the initial reaction period. By so doing,the proportion of monoperoxyphthalic acid reacting with further phthalic anhydride to form diphthaloyl peroxide can be minimised, and, where the temperature is in the region of 10'Cto 12'C or lower during the initial - 4 GB 2 163 175 A -4 reaction period,that proportion is substantially nil. It will be, recognised thatthe maximum temperature appertainin g-throughoutthe initial reaction period thatcan be tolerated depends upon the proportion of diphthaloyl peroxide thatcan be tolerated;the higher 70 thetemperaturethehigher the proportion. For exam ple, ifthe temperature is maintained at 200C during the - initial reaction period, the proportion of diphthaloyl peroxide can be in the region of about 5%. In consequence, the reaction temperature during the initial reaction period is in practice in the range of 0 to 30'C and preferablyfrom 5 to 150C.

Afterthe reactants have been broughtinto contact orwithin 15 minutes thereof, the temperature ofthe slurry can be allowed to rise,, since the risk of diphthaloyl peroxide forming is much lowerthan -during the initial reaction period, suitably to-a - temperature in the rangeof 15to 300C. During.this latter period, M MPP is forming as a pa rticu late solid.

Fora batch process,the secondary reaction period typicafly lastsfrom 0.5 hoursto 5 hours, and often- from 1 -to 2 hours.

Afterthe MMPP has been formed as a particu late precipitate, it can then be separated employing standard solidlliquid separators such as drum and plate filters, or centrifuges. it is then, preferably, washed with a non-aqueous solvent for phthalic anhydride, which can be, conveniently, a small amount of fresh solventemployed as the reaction solvent. The separated solid can then be dried, but preferably, where it is known that in the dried state it would not be suflciently insensitive to impact orto thermal shock, it is desensitised whilst it is still in the damp state by intimate contact with a suitable amount of one or more of the desensitising compounds 100 described herein.

Where-separa d liquorstill contains hydrogen peroxide andlorphthalicanhydride andlorMPPA, it can be re-employed, suitably by making-up the concentrations of the reactants to within the ranges of 105 mole ratios described hereinbefore and particularlyto achieve steadystate levels underthe reaction conditions described. Thus, the process in some embodimerits, is cyclical comprising the steps of 45 (i) dissilution of aqueous hydrogen peroxide, in a 110 selected organic solvent and introduction of phthalic anhydride and magnesium compound therein, in amounts as described herein; (H) separating particulate MMPP from the liquid 50 phase determining the contests of phthalic anhyd- ride, MPPA, water, hydrogen peroxide and magne sium compound in the liquid phase; (iv) recycling the liquid phaseto step (i) for make-up of the reagents, preferably achieve steady stateto levels, the process applying mutatis-mutandis to the production of the other magnesium salts in classes 1 to.3. By so recycling, it has been found that the average particle size of the product can be increased, the proportion of fine particles in the 125 producttending to diminish.

When a steady state is obtained step (iii) need not be carried out every cycle, butthe previously calculated amountsused.

-Itwill be recognised thatthe ratios of reagents introduced in subsequent cycles can appearto be - outside the ranges of ratios specified earlier herein. Assuming that the-volume of filtratelwashings on. recycle is adjusted where necessaryto approximately the same levelthe amount of phthalic anhydride introduced in subsequent cycles is, in many cases, the amount of hydrogen peroxide introducedis approximately 60% of that introduced in the first cycle and the amount of magnesium oxide introduced likewise is substantiallythe same in first and subsequent cycles. In practice, this means that in the subsequent cycles the mole ratio of Mg:PA introduced is preferably in the range of 5:4to 4:5, the hydrogen peroxide: PA mole ratio is preferably in the range-off 1.1:ltol.3:1,andtheamountofPAintroducedis often in the range 0.36 to 0.75 moles perl 0009 reaction mixture.

Thebleaching agent mayoptionally also include a peroxygen compound in addition to the peroxyacid compound. The useful peroxygen compounds include - compoundsthat release hydrogen peroxide in aqueous media, such as, alkali metal perborates, e.g. sodium perborate and potassium perborate, alkali metal perphosphates and. alkali metal percarbonates.

The alkali metal perborates are usually preferred because of their commercial availability and relatively lowcost. If desired. an organic activator may be used in conjunction with such peroxygen compound.

The bleaching detergent compositions ofthe inven- tion are characterised by being su bstantia lly free of (i) water-soluble silicate compounds; (ii) organic activatorsfor peroxygen compounds; and (iii) agglomerate particles which are essentially comprised of a mixture of three components: an organic activatorforthe peroxygen compound; a water-insoluble silicate compound, such as clay orzeolite; and a nonionic surfactant, such mixture being at least 80%, by weig t of the agglomeric particles. The agglomerate particles which are precluded for use herein are of thetypeformed in equipment such as a pan granulator and serveto incorporate the bleach activator in a matrixof materials as described in European Patent Publication No. 0 ' 028,432. In one particular embodiment of the invention,the bleaching compositions are further characterised by being substantially free of sequestering agents having a stability constantfor CU21 complex formation above about 20 in water at 25'C and at an ionic strength of 0.1 molellitre.

The water-insolu_ble silicate materials which may be advantageously employed in the present bleaching compositions are preferably aluminosilicates such aszeolites and smectite-type clays. The crystalline types of zeolitewhich may be employed include those described in "Zeolite Molecular Series" by Donald W.

Breck, published in 1974 byJohn Wiley &Sons, typical commercially available zeolites being listed inTable 9.6 at pages 747-749 of the text, such Table being incorporated herein by reference. Typical commercially available zeolites includeType 3A Unde,Type 4A Linde,Type 4A-30 Unde, Type 4A-Xl-1-2 Linde, Type EA Linde,Type 1 OX Linde, Type 13X Unde, Type AW-300 Linde Type AW-500 Linde, SK40 Linde,-SK 41 Linde,SK45Linde, SK120Linde,SK500Linde, Zeolon-100Norton,Zeolon-200Norton,Zeolon-300 Norton,Zeolon-500 Norton, Zeolon-900 Norton, Type GB 2 163 175 A 5 3A Davison, Type 4A Davison,, Type 5A Davison and Type 13X Davison. Zeolite structures of type A are especially desirable and are extensively described in the art; see, for example, page 133 of the aforemen tioned Brecktext, as well as U.S. Patent No. 2,882,243. 70 The zeolites are particularly useful as builder salts in heavy duty detergent compositions.

The aforementioned smectite-type clays arethree layerclays characterised bythe ability of the layered structureto increase its volume several-fold by swelling orexpanding when in the presence of water toform athixotropic gelatinous substance. There are two classes of smectite-type clays: in thefirstclass, aluminium oxide is present in thesilicate crystal lattice; in the second class, magnesium oxide is present in the silicate crystal lattice. Atom substitution by iron. magnesium, sodium, potassium, calcium and the like can occurwithin the crystal lattice of the smectite clays. It is customary to distinguish between clays on the basis of their predominant cation. For example, a sodium clay is one in which the cation is predominantly sodium. With regard to the present bleaching detergent compositions, aluminium sili cates wherein sodium is the predominant cation are preferred, such as, for example, bentonite clays.

Among the bentonite clays, those from Wyoming (generally referred to as western or Wyoming bento nite) are especially preferred. Calcium and magne sium clays are also useful albeit less preferred for purposes of this invention.

Preferred swelling bentonites are sold underthe trademark Mineral Colloid, as industrial bentonites, by - Benton Clay Company, an affiliate of Georgia Kaolin Co. These materials which are the same as those formerlysold underthe trademark TH IXO-J EL, are selectively mined and beneficiated bentonites, and those considered to be most useful are available as Mineral Colloid No's. 101, etc. corresponding to THIXO-JELs No's. 1, 2,3 and 4. Such materials have PH's (6% concentration in water) in the range of 8to 105 9.4, maximum free moisture contents of about 8% and specific gravities of about 2.6, and forthe pulverised grade at least about 85% (and preferably 100%) passesthrough a 200 mesh U.S. Sieve Series sieve 45 (having openings 74 microns across). More preferably,.the bentonite is one wherein essentially all the particles (i.e. at least 90% thereof, preferably over 95%) passthrough a No. 325 sieve (having openings 44 microns across) and most preferably all the 50 particles pass through such a sieve. The swelling capacity of the bentonites in water is usually in the range of 3 to 15 Milgram, and its viscosity, at a 6% concentration in water, is usuallyfrom about 8 to 30 centipoises. 55 In a particular preferred embodiment of the invention, the carrier particles comprise agglomerates of finely divided bentonite, of particle sizes less than No. 200 sieve (i. e. less than 74 microns), agglomerated to particles of sizes essentially in the No's. 10-100 sieve 60 range (0.149 mm to 2mm), of abulk density in the range of 0.7 to 0.9 9/m] and a moisture content of 8 to 13%. Such agglomerates include about 1 to 5% of a binder oragglomerating agentto assist in maintaining the integrity of the agglomerates until they are added 65 to water, in which it is intended that they disintegrate and disperse.A detailed description of the method of preparation of such agglomerates is setforth in GB 2121843 which is incorporated herein by reference. As stated on pages 4 and 5 of GB 2121843, the bentonite agglomerates may be made by spraying an aqueous solution of a binder onto the moving surfaces of the finely divided bentonite and keeping the finely divided bentonite and the resulting agglomerating particles in motion until a major proportion of the particles is agglomerated so as to be within the No's. 10-100 sieve range (U.S. Sieve Series, 10 mesh having openings 2000 microns across and 100 mesh 149 microns across). When that happensthe moisture content of the agglomerate will usually be in the range of 20to 35% and the binder contentwill be about 1 to 5%, when the aqueous spray solution employed is at a concentration of 2 to 20%. Preferably the binder content of the spray will be from 4to 10%, more preferably 6 to 9%, e.g. 7 or 7.5% and the moisture content of the agglomerated particles before drying, will be 23 to 31 %, e.g. 27%. The spray will normally be at an elevated temperature when it is sprayed onto the finely divided bentonite powder, which temperature will usually be in the range of 65 to 85C, preferably 65 to 75'C, e.g. about 70'C. The spray will be in finely divided dropletform. preferably generated by a spray nozzle designed to produce a flat spray pattern. which spray is directed transversely with respectto a screen of particles in the agglomerator. The spray nozzle will preferably be of an orifice diameter in the range of 0.05 to 0.1 mm, the spray will be directed at an angle between 400 and 1200 and across a failing stream of particles to be agglomerated. and spraywill be at a pressure in the range of 0.5to 20 kg/sq cm, preferably 1 to 6 kg/sq cm.

Although various apparatuses may be used forthe agglomeration, that which is most preferred is an O'Brien agglomerator, in which an inclined drum, equipped with a plurality of breaker bars, is so constructed as to produce a screen of particles onto which the spray impinges. The O'Brien agglomerator may be operated on a batch or continuous basis and may be subject to automatic control with respect to feeds, sprays, removal rates and agglomerate particle sizes. Normallythe agglomeration period will bethat which isjust sufficieritto produce particles of the desired sizes, e.g. No's 10-100 sieve size (U.S. Sieve Series, 10 mesh has openings 2000 microns across. and 100 mesh has openings 149 microns across), but in some cases additional tumbling may be utilized after completion of spraying of the agglomerating liquid. However. spraying will not be continued so long as to destroythe craggy nature of the particle surfaces. Usuallythe residence time in the agglomera- tor, whether operated continuously or as a batch, will be within the range of 10 to 40 minutes, preferably 15 to 30 minutes, e.g. 22 minutes, but residence time depends on the design and size of the agglomerator and the speed of rotation or other movement thereof, which speed normally wil 1 be from 3 to 40 r.p.m., preferably 6 to 20 r.p. m.

After completion of agglomeration the moist agglomerate is next dried. Some evaporation of moisture may occur during agglomeration but it is only a fraction of that required to lowerthe moisture 6 GB 2 163 175 A 6 conteritto the desired range. Various types of dryers maybe employed but it is preferred to utilize a fluid bed type dryer. In such a small scale dryer, with an air temperature of WC and a flow rate of about7,000 litres per minute, two kilograms of "wet" agglomerate are dried to a moisture content in the range of 8 to 13% in from five to ten minutes. For larger charges ofthe agglomerate the airflow rate is preferably increased accordingly, so thatthe drying will take about the same period of time, although times within the range of 3 to 30 minutes are also acceptable. During such times the mass flow rate of moistu re to the surface of the agglomerate causes migration of internal silicate to the surface,thereby increasing the surface concen- trationthereof and better strengthening the agglomerated particles resulting. Of course, when the size of the charge and the production rate outstripthe equipment design, largerdryers will be employed.

Instead of utilizing theTHIXO-JEL or Mineral Colloid bentonites one may also employ equivalent competitive products,such asthatsold byAmerican Colloid Company, Industrial Division, as General Purpose Bentonite Powder, 325 mesh, which has a minimum of 95% thereof finerthan 325 mesh or44 microns in diameter (wet particle size) and a minimum of 96% finerthan 200 mesh or74 microns diameter (dry particle size). Such a hydrous aluminium silicate is comprised principally of montmorillonite (90% minimum), withsmaller proportions offeldspar, biotite and selenite. Atypical analysis, on an "anhydrous" basis, is 63.0% silica, 21.5% alumina, 3.3% of ferric iron (as Fe20A0.4% of ferrous iron (as FeO), 2.7% of magnesium (as MgO), 2.6% of sodium and potassium (as Na20), 03% of calcium (as CaO), 5.6% of crystal water (as H20) and 0.7% of trace elements.

Althoughthe western bentonites are preferred it is also possible to utilize synthetic bentonites, such as those which may be made bytreating Italian or similar bentonites containing relatively small proportions of exchangeable monovalent metals (sodium and potas- 105 sium) with alkaline materials, such as sodium carbon ate, to increasethe cation exchange capacities of such products. It is considered that the Na20 content of the bentonite should be at least about 0.5%, preferably at least 1 % and more preferably at least2% so thatthe clay will be satisfactorily swelling, with good soften ing and dispersing properties in aqueous suspension.

Preferred swelling bentonites of the synthetic types described are sold underthe trade names Laviosa and Winkelmann, e.g. Laviosa AGB and Winkelmann G-1 3. 115 The compositions of the present invention can contain one or more surface active agents selected from the group of anionic, nonionic, cationic, ampholytic and zwitterionic detergents.

Among the anionicsurface active agents useful in the present invention arethose surface active com pounds which contain an organic hydrophobic group containing from 8 to 26 carbon atoms and preferably from 1 Oto 18 carbon atoms in their molecular structure and at least one water-solubilizing group selected from the group of sulphonate, sulphate, carboxylate phosphonate and phosphate so as to form a water soluble detergent.

Examples of suitable anionic detergents include soaps, such as, the water-so luble salts (e.g. the 130 sodium, potassium, ammonium and alkanolammonium salts) of higherfatty acids or resin salts containing from 8to 20 carbon atoms and preferably 1 Oto 18 carbon atoms. Suitablefatty acids can be obtained from oils and waxes of animal orvegetable originjor example, tallow, grease, coconut oil and mixtures thereof. Particularly useful arethe sodium and potassium salts of thefatty acid mixtures derived from coconutoil andtallowjor example, sodium coconutsoap and potassium tallowsoap.

The anionicclass of detergents also includesthe water-soluble sulphated and sulphonated detergents having an alkyl radical containing from 8to 26, and preferablyfrom 12to 22 carbon atoms. (Theterm "alkyl" includesthe alkyl portion of the higheracyl radicals). Examples of the sulphonated anionic detergents are the higheralkyl mononuclear aromatic sulphonates such asthe higher alkyl benzene sulphonates containing from about 10 to 16 carbon atoms in the higher alkyl group in a straight or branched chain, such as, for example, the sodium, potassium and ammonium saltsof higher alkyl benzene sulphonates, higher alkyl toluene sulphonates and higher alkyl phenol sulphonates.

Other suitable anionic detergents arethe olefin sulphonates including long chain alkene sulphonates, long chain hydroxyalkane sulphonates or mixtures of alkene sulphonates and hydroxyalkane sulphonates. The olefin sulphonate detergents may be prepared in a conventional manner bythe reaction of SO'with long chain olefins containing from about8to 25, and preferablyfrom 12to 21 carbon atoms, such olefins having theformula RCC=CHRwherein R represents a higher alkyl group of from 6to 23 carbons and R' represents an alkyl group containing from 1 to 17 carbon atoms, or hydrogen to form a mixture of sultones and alkene sulphonic acids which isthen treated to convertthe sultones to sulphonates. Other examples of sulphate orsulphonate detergents are paraffin sulphonates containing from 10 to 20 carbon atoms, and preferablyfrom 15to 20 carbon atoms. The primary paraffin sulphonates, are made by reacting long chain alpha olefins and bisulphites. Paraffin sulphonates having the sulphonate group distributed along the paraffin chain are shown in U.S. Nos. 2,503,280, 2,507,088; 3, 260,741; 3,372,188 and German Patent No. 735,096.

Other suitable anionic detergents are sulphated ethoxylated higherfatty alcohols of theformula RO(C21-140)mSO3M, wherein R represents a fatty alkyl of from 1 Oto 18 carbon atoms, m is from 2 to 6 (preferably having a value from about 115 to 112the numberof carbon atoms in R) and M is a solubilizing salt-forming cation, such as an alkali metal, ammo- nium, lower alkylamino or lower alkanolamino, or a higher alkyl benzene sulphonate wherein the higher alkyl is of 1 Oto 15 carbon atoms. The proportion of ethylene oxide in the polyethoxylated higher alkanol sulphate is preferably 2 to 5 moles of ethylene oxide groups per mole of anionic detergent, with three moles being most preferred, especially when the higheralkanol is of 11 to 15 carbon atoms. To maintain the desired hydrophile-lipophile balance, when the carbon atom content of the alkyl chain is in the lower portion of the 10 to 18 carbon atom range,the 7 ethylene oxide content of the detergent may be reduced to about two moles per mole whereas when the higher alkanol is of 16 to 18 carbon atoms in the higher part of the range, the nu mber of ethylene oxide grou ps may be increased to 4 or 5 and in some cases to 70 as high as 8 or 9. Similarly, the salt-forming cation may be altered to obtain the best solu bility. It may be any suitably solubilizing metal or radical but will most frequently be alkali metal, e.g. sodium, or ammonium.

If lower alkylamine or alkanolamine g rou ps a re 75 utilized the alkyls and alkanols will usually contain from 1 to 4 carbon atoms and the amines and alkanolamines may be mono-, di- and tri-substituted, as in monoethanolamine, diisopropanolamine and trimethylamine. A preferred polyethoxylated alcohol 80 sulphate detergent is available from Shell Chemical Company and is marked at Neodol 25-3S.

The most highly preferred water-soluble anionic detergent compounds are the ammonium and substi tuted ammonium (such as mono, di and tri-ethanola85 mine), alkali metal (such as, sodium and potassium) and alkaline earth metal (such as, calcium and magnesium) salts of the higheralkyl benzene sui phonates, olefin sulphonates and.higher alkyl sul phates. Among the above-listed anionics,the most preferred are the sodium linear alkyl benzene sul phonates (LABS), and especialiythose wherein the alkyl group is a straight chain alkyl radical of 12 or 13 carbon atoms.

The non ionic synthetic organic detergents are characterised bythe presence of an organic hyd rophobic group and an organic hydrophilic group and are typically produced bythe condensation of an organic aliphatic or alkyl aromatic hydrophobic com pound with ethylene oxide (hydrophilic in nature).

Practically any hydrophobic compound having a carboxy, hydroxy, amido or amino group with a free hydrogen attached to the nitrogen can be condensed with ethylene oxide orwith the polyhydration product thereof, polyethylene glycol,to form a nonionic detergent. The length of the hydrophilic or polyox yethylene chain can be readily adjusted to achieve the desired balance between the hydrophobic and hyd rophilicgroups.

The nonionic detergent employed is preferably a poly-lower alkoxylated higher alkanol wherein the alkanol is of 10 to 18 carbon atoms and wherein the number of moles of lower alkylene oxide (of 2 or3 carbon atoms) is from 3 to 12. Of such materials it is preferred to employthose wherein the higher alkanol is a higherfatty alcohol of 11 to 15 carbon atoms and which contain from 5 to 9 lower alkoxy groups per mole. Preferably, the lower alkoxy is ethoxy but in some instances it may be desirably mixed with propoxy, the latter, if present, usually being a minor (lessthan 50%) constituent. Exemplary of such compounds arethosewherein the alkanol is of 12to 15 115 carbon atoms and which contain about7 ethylene oxide groups per mole, e.g. Neodol 25-7 and Neodol 23-6.5,which products are made by Shell Chemical Company, Inc. (Theword "Neodol" is a trade mark.) Theformer is a condensation product of a mixture of higherfatty alcohols averaging 12to 15 carbon atoms, with 7 moles of ethylene oxide andthe latter is a corresponding mixture wherein the carbon atom GB 2 163 175 A 7 content of the higher fatty alcohol is 12 to 13 and the number of ethylene oxide groups per mole averages about 6.5. The higher alcohols are primary alkanols. Other examples of such detergents includeTergitol 15-S-7 and Tergitol 15-S-9, both of which are linear secondary alcohol ethoxylates made by Union Carbide Corporation. (The word---Tergitol-is a trade mark.) The former is a mixed ethoxylation product of an 11 to 15 carbon atom linear secondary alkanol with seven moles of ethylene oxide and the latter is a simila r product but with nine moles of ethylene oxide being reacted.

Also useful in the present compositions arethe higher molecularweight nonionics, such as Neodol 45-11, which are similarethylene oxide condensation products of higherfatty alcohols,the higherfatty alcohol being of 14to 15 carbon atoms andthe numberof ethylene oxide groups per mole being about 11. Such products are also made byShell Chemical Company.

Zwitterionic detergents such as the betaines and sulphobetaines having thefollowing formula are also useful:

R2 R3 0 wherein R represents an alkyl group containing from 8to 18 carbon atoms, each of R' and R 3 independently represents an alkyl or hydroxyalkyl group containing from 1 to 4 carbon atoms, R 4 represents an alkylene or hydroxyalkylene group containing from 1 to 4 carbon atoms, and X represents C or S:O. The alkyl group can contain one or more intermediate linkages such as amido, ether, or polyether linkages or non-functional substituents such as hydroxyl or halogen which do not substantially affectthe hydrophobic character of the group. When X is C, the detergent is called a betaine; and when X is S:O, the detergent is called a sulphobetaine or sultaine.

Cationic surface active agents may also be employed. They comprise surface active detergent compounds which contain an organic hydrophobic group which forms part of a cation when the compound is dissolved in water, and an anionic group. Typical cationic surface active agents are amine and quaternary ammonium compounds.

Examples of suitable synthetic cationic detergents include: normal primary amines of theformula RNH2 wherein R is an aikyl group containing from 12 to 15 atoms; diamines having the formula RNHC2H4NH2 wherein R is an alkyl group containing from 12 to 22 carbon atoms, such as N-2-aminoethyl-stearyl amine and N-2-aminoethyl myristyl amine; amide-linked amines such asthose having theformula R' CON HC2H4N H2 wherein R' represents an alkyl group containing from 8to 20 carbon atoms, such as N-2-amino ethylstearyl amide and N-amino ethyl- myristyl amide; quaternary ammonium compounds wherein typically one of the groups linked to the nitrogen atom is an alkyl group containing from 8to 22 carbon atoms and three of the groups linked to the - 8 GB 2 163 175 A 8 nitrogen atom are alkyl groups which contain 1 to 3 carbon atoms, including alkyl groups bearing inert substituents, such as phenyl groups, and there is presentan anion such as halogen, acetate, methos ul- phate, etc.The alkyl group may contain intermediate linkages such as amide which do notsubstanfla 1 ly affectthe hydrophobic character of the group,for example ' stearyl amido propyl quaternaryammonium chloride. Typical quaternary ammonium detergentsare ethyl-dimethyi-stearyi-ammonium chlorIde, benzyi-dimethyistearyl ammonium chloride, trimethyi-stearyl ammonium chloride, trimethylcetyl ammonium bromide, dimethyi-ethylmlauryl ammonium chloCide, dimethyi-propyi-myristyl ammonium chloride,and the corresponding methosulphates and acetates.

AmphoVic detergents are also suitable forthe invention. Ampholytic detergents are well known in the artand many operable detergents of this class are disclosed by Schwart:4 Perry and Berch in the - aforementioned -Surface Active Agents and Detergents". Examples of suitable amphoteric detergents include: alkyl beta-iminodipropionates, RN(C21-14COOM)2; alkyl beta-amino propionates, RN(H)C21-14COOM; and long chain imidazolederivatives havingthe generalformula:

CH2 N CH2 1 1 R--C-N-CH2CH2OCH2COOM 0H CH2COOM - wherein in each of the above formulae R represents an acyclic hydrophobic group c ontaining from 8 to 18 carbon atoms and M is a cation to neutralize the charge of the anion. Specific operable amphoteric detergents include the disodium salt of undecylcyclo - imidinium - ethoxyethionic acid-2- ethionic acid, dodecyl beta alanine, and the inner salt of 2trimethylamino lauric acid.

The bleaching detergent compositions of the inventi-on optionally contain a detergent builder ofthe - type commonly used in detergentformulations. -Useful builders include any of the conventional Anorganic water-sol uble, builder salts, such as, for example, water-soluble salts of phosphates, pyrophosphates, orthophosphates, polyphosphates, carbonatesi and the like. Organic builders include water-soluble phosphonates, poiyphosponates, polyhydroxysul phonates, polyacetates, carboxy- latespolycarboxylates, succinates and the like.

Specific examples of inorganic phosphate builders -includesodium and potassium tripolyphosphates, pyrophosphates and hexametaphosphates. The organic polyphosphonates specifically includejor example, the sodium and potassium salts of ethane 1 -hydroxy-1, 1 - diphosphonic acid and the sodium and potassium salts of ethane-1, 1, 2- triphos phonic acid. Examples ofthese and otherphosphorus buil- dercompounds are disclosed in U.S. Patent Nos.

3,213,030; 3,422,021,3,422,137 and 3,400,176. Pentasodium tripolyphosphate and t rasodiumpyrophos- phate are especially preferred water-soluble inorganic builders.

Specific examples of non-p-hosphorus inorganic builders include water-soluble inorganic carbonate - and bicarbonate salts. The alkali metal, forexample, sodium and potassium, carbonates and bicarbonates are particularly useful herein.

Water-soluble organic builders arealso useful. For example, the alkali metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates and polyhydroxysu 1 phonates are useful buildersforthe compositions and processes ofthe invention. Specific examples of polyacetate and polycarboxylate b uilders include sodium, potassium, lithium, ammonium and substituted ammoni urn salts of ethylene diaminetetracetic acid, nitfilotriacetic acid, benzene polycarboxyllc (i.e. penta- and tetra-) acids, carboxymethoxysuccinica Cid and citric acid.

Water-insoluble builders may also be used, particularly,the complex silicates and more parficularlythe complex sodium alumino silicates such as,,zeolites, e.g. Zeolite 4A, a type of zeolite molecule wherein the univalent cation is sodium andthe pore size is about4 Angstroms (0.4 nm).The preparation of such type zeolite is described in U. S. Patent3,114,603.The zeolites may be amorphous orcrystalline and have waterof hydration as known in the art.

An inert, water-soluble filler salt is desirably included in the laundering compositions of the invention. A preferred filler salt is an alkali metal sulphate,such as, potassium orsodium sulphate,the latter being especially preferred.

Various adjuvants may be included in the laundry detergent compositions ofthe invention. In general, these include perfumes, colourants, e.g. pigments and dyes bleaches, such as, sodium perborate. antiredeposition agents, such as alkali metal salts of carboxymethylcellulose; optical brighteners, such as anionic, cationic or nonionic brighteners., foam stabilizers, such as alkanolamides and the like, all of which are well-known in the fabricwashing artfor use in detergent compositions. Flow promoting agents, commonly referred to asfiow aids, may also be 10Cemployed to maintain the particulate compositions asfree-flowing beads or powder. Starch derivatives and special clays are commercially availableas additives which enhancethe flowability of otherwise tacky or pasty particulate compositions, two of such 1 05clay additives being presently marketed underthe tradenames"Satintone" and "Microsil".

A preferred bleaching detergent composition in accordance with the invention typically comprises (a) from about2to 50%, byweight, of a bleaching agent 11 Ocomprising a peroxyacid compound andlora watersoluble saitthereof, (b) from about 5to 50%, by weight, of a detergent surface active agent; (c) from about 1 to about 60%, by weight, of a detergent builder salt; and (d) from about 0.1 to about 10%, by weight, of a sequestering agent; such composition being characterised by being substantiallyfree-of (i) water-soluble silicate compounds; (H) organicactivatorsfor peroxygen compounds; and (iii) agglomerate particles which essentially comprise an activator, a 120water-insoluble silicate compoun'd and a nonionic surfactant. The balance ofthe composition will 9 GB 2 163 175 A 9 predominantly comprise water, filler salts, such as sodium sulphate, and minor additives selected from among the various adjuvants described above.

The particuiate bleaching detergent compositions of the invention are prepared byadmixing the bleaching agent and optional sequestering agent with thespray-dried detergent composition,the latter being formulated so asto avoidthe use of watersoluble silicate compounds, most notably, sodium silicate. The presence of very minor amounts of water-soluble silicate compounds in the final compositions, i.e. below about 0.5%, preferably below about 0.2%, and most preferably no greaterthan aboutO.1 %, by weight, such as may occurwith the use of silicate-containing pigments or dyes, or upon contact of the aqueous crutcher slurry with residual amounts of sodium silicate in the spraytower, is contemplated by the present invention.

The spray drying of a silicate-free detergentfor- mulation may result in a relatively dusty granular product due to the absence of silicate as a binderfor the spray dried beads. However, alternative organic binder materials may be employed, such as, for example, starch, ca rboxymethyl-cel 1 u lose and mate- rials comparable thereto. The strength of the spray dried beads may also be enhanced by maximizing the solids content of the silicate-free slurry in the crutcher andlor by maintaining the inlet temperature of the hot air stream in the spraytower as low as possible.

The bleaching agent can be mixed either directly With the spray dried powder orthe bleaching agent and optional sequestering agent can be separately or collectively coated with coating material to prevent premature activation of the bleaching agent. The coating process is conducted in accordance with procedures well known in the art. Suitable coating materials include compounds such as magnesium sulphate, polyvinyl -alcohol, lauric acid and its salts and the like.

The bleaching detergent compositions of the invention are added to the wash solution in an amount sufficientto providefrom about 3to about 100 parts of a ctive oxygen per million parts of solution, a concentration of from about 5to about40 ppm being generally preferred.

The particulate bleaching detergent compositions described above maybe produced by such methods as spray-drying, dry-blending, or agglomeration of the individual components.

The following examples illustrate the invention. EXAMPLE 1 A preferred silicate-free bleaching detergent composition is comprised of the following:

Component Sodium linear C10-C13 alkyl benzene sulphonate Ethoxylated C11-Cla primary alcohol (11 moles EZ) per mole alcohol) Soap (sodium salt of C12-C22 carboxylic acid) Pentasodium tripolyphosphate (TPP) 32.0 EDTA Weight Percent 6 4 0.5 Monoperoxyphthalic acid (MPPA), magnesium salt Carboxymethyl cellulose Optical brighteners, pigment and perfume 0.4 Proteolytic enzymes Sodium sulphate and water 7 0.5 balance The foregoing product is produced by spray drying an aqueous slurry containing 60%, byweight, of a mixture containing all of the above components exceptthe enzyme, perfume and monoperoxyphthalic acid (MPPA). The resultant particulate spray dried product has a particle size in the range of 14 mesh to 270 mesh, (U.S. Sieve Series) (53 microns to 1.19 mm). The spray dried product is then mixed in a rotary drum with the appropriate amounts of MPPA of similar mesh size, enzyme and perfume to yield a particulate product having a moisture of approx- imately 14%, by weight.

The above-described product is used to wash soiled fabrics by handwashing as well as in an automatic washing machine, good laundering and bleaching performance being obtained for both methods of laundering.

Other satisfactory products can be obtained by varying the concentrations of the following principal components in the above-described composition as follows:

Component Alkyl benzene sulphonale Ethoxylated alcohol Soap TPP Enzymes EDTA MPPA Weight Percent 412 1-5 1-10 15-50 0.1-1 0.1-2 1-20 For highly concentrated heavy duty detergent powder, the alkyl benzene sulphonate, TPP and the soap components in the above described composi tion may be deleted, and the ethoxylated alcohol content may be increased to an upper limit of 20%.

EXAMPLES 2A and 28 (Example 2B is a comparison example.) Bleaching tests are carried outasdescribed below comparing the bleaching performance of a water soluble silicate-free bleaching detergent composition in accordance with the invention and a corresponding silicate-containing composition,the lattercomposition being comparable to the former in nearlyall respects exceptforthe presence of a water-soluble silicate compound. The bleaching agent employed is a mixture of monoperoxyphthalic acid salt and sodium perborate. The compositions areformulated by post-adding to a spray-dried particulate detergent composition, granules of the H-48 bleaching composition (described in the footnote of Table 1) toform GB 2 163 175 A 10 the bleaching detergent compositions A and B shown inTable 1 below.The numbers indicated in theTable representthe percentageof each component, by weight, in the composition, Component TABLE 1

Sodium linear C10-C13 alkyl benzene sulphonate Ethoxylated C11-CI8 primary alcohol (11 moles EO per mole alcohol) Soap (Sodium salt of C12- C22 carboxylic acid) Sodium silicate 01a23-2Si02) Pentaosiduz tripolyphosphate (TPP) Optical brightener (Stilbene) Sodium perborate tetrahydrate H-48(1) EDTA (Disodium salt) Sodium Sulphate Water SR".sition - A B Time (min.) 3 7 (Silicate- (silicate- 30 free) - containintz) 40 6.00%, 3.50 2.50 35.00 0.22 3.00 9.00 1.00 35.00 balance 6.00% 3.50 2.50 9.00 35-00 0.22 3.00 9-00 1.00 10.60 balance (1) A bleaching composition sold by Interox Chemicals Limited, London, containing about 65 wt % magnesium monoperoxyphtha late, 11 wt % magnesium phthalate, balance H20.

TEST PROCEDURE The active oxygen concentration in solution is determined as a function of timefor separate wash solutions containing compositionsA and B, respectively, using the following procedure:

One litre of tap water is introduced into a two litre beakerandthen heatedto a constant tem peratu re of WC in a water bath. Ten grams of the particular composition being tested (A or B) are added tothe beaker (time = 0) with thorough mixing to form a uniform wash solution. After given periods of time (3, 7,13,20,30,40 and 50 minutes), a 50 mi aliquot is withdrawn from the wash solution and thetotal active oxygen concentration is determined bythe procedure setforth below. Determination of TotalActive 02 Concentration The aforementioned 50 mi aliquot is poured into a 300 mi Erlenmeyerflask containing 15 mi of a sulphuric/molybdate mixture,the latter mixture hav ing been prepared in large-scale amounts by dissolv ing 0.18 grams of ammonium molybdate in 750 mi of deionized waterand then adding thereto 320 m[ of H2S04 (about36N) with stirring. The solution in the Erlenmeyer isthoroughly mixed and 5 mI of 10% M solution in deionized water isthen added thereto. The Erlenmeyer is sealed with a stopper, agitated and then allowed to stand in a dark place for aboutseven minutes. The solution in theflask is then titrated with 90 a solution of 0.1 N sodium thiosulphate in deionized water. The volume of thiosulphate required in mi, is equal to thetetal active oxygen concentration, in nillimolellitre, in the wash solution. Thetests results -the two compositions tested are shown in Table 2 95 kw.

TABLE 2 Total Active Oxygen in Wash Solution (mmol/litre) Example 2A Example 2B (Silicate-free) (Silicate-containing) 4.8 2.4 4.4 4.2 3.9 3.7 3.4 3.2 1.2 1.0 0.8 0.6 0.5 0.4 As shown in Table 2, the silicate-free composition A is significantly more stable and is characterised by a

Claims (1)

1. far slower loss of active oxygen from solution than the corresponding

   silicate-containing composition B. CLAIMS

   1. A bleaching detergent composition comprising bleaching agent comprising a peroxyacid compound andlor a water soluble salt thereof and a surface active agent, the composition being substantially free of (i) water-soluble silicate compounds, (ii) organic activators for peroxygen compounds, and (iii) agglomerate particles which essentially comprise a mixture of an activator, a water-insoluble silicate compound and a nonionic surfactant.

   2. A composition as claimed in Claim 1, which is particulate.

   3. A composition as claimed in Claim 1 or 2, wherein the surface active agent is an anionic, cationic, nonionic, ampholytic or zwitterionic detergent.

   4. A particulate bleaching detergent composition comprising:

   (a) a bleaching agent comprising a peroxyacid comprising a peroxyacid compound andlora watersoluble saitthereof; and (b) at least one surface active agent selected from anionic, cationic, nonionic, ampholyticand zwitter- ionic detergents; said bleaching detergent composition being substantially free of (1) water-soluble silicate compounds; (H) organic activatorsfor peroxygen compounds; and (iii) agglomerate particles which essentially comprise a mixture of an activator, a water-insoluble silicate compound and a nonionic surfactant.

   5. A composition as claimed in anyone of Claims 1 to 4 also containing a sequestering agent. - 6. A composition as claimed in Claim 5, wherein the sequestering agent comprises ethylene diamine tetraacetic acid andlor a water-soluble saitthereof.

   7. A composition as claimed in Claim 5 or 6, wherein the sequestering agent comprises diethyiene tria mine penta methylene phosphon ic acid andlor a water-soluble salt thereof.

   8. A composition as claimed in anyone of Claims 1 to 7, wherein the bleaching agent comprises monoperoxyphthalic acid andlor a water-soluble salt thereof.

   9. A composition as claimed in Claim 8, wherein the bleaching agent comprises magnesium monoperoxyphthalate.

   10. A composition as claimed in Claim 4, wherein the bleaching agent also contains a peroxygen compound.

   11. A composition as claimed in Claim 10, where- 11 GB 2 163 175 A 11 inthe peroxygen compound isan alkali metal perborate.

   12. A composition as claimed in anyone of Claims 1 to 11 also containing a detergent builder salt.

   13. A composition as claimed in Claim 12, wherein the builder salt is a zeolite.

   14. A composition as claimed in anyone of Claims 1 to 13, wherein the surface active agent is an anionic detergent.

   15. A composition as claimed in Claim 14, where- in the anionic detergent is a linear alkyl benzene sulphonate.

   16. A composition as claimed in anyone of Claims 1 to 15, also containing a bentonite clay.

   17. A bleaching detergent composition com- 80 prising:

   (a) from 1 to 50%, byweight, of a bleaching agent comprising a peroxyacid compound andlora water soluble salt thereof; (b) from 5 to 50%, by weight, of a detergent surface active agent selected from anionic, cationic, non ionic, ampholytic and zwitterion ic detergents; (c) from 1 to 60%, by weight, of a detergent buildersalt; (d) from 0.1 to 10%, by weight, of a sequestering agent; and (e) the balance comprising water and optionally a fillersalt; said bleaching detergent composition being substantial ly free of (i) water-soluble silicate compounds; fli) organic activators for peroxygen compounds and (iii) agglomerate particles which essentially comprise a mixture of an activator, a water-insoluble silicate compound and a nonionic surfactant.

   18. A composition as claimed in Claim 17, where- 100 in the bleaching agent comprises monoperoxyphtha lic acid andlor a water-soluble saitthereof.

   19. A composition as claimed in Claim 17, where in the bleaching agent comprises magnesium monoperoxyphthalate.

   20. A composition as claimed in Claim 17,18 or 19, wherein the bleaching agent also contains a peroxygen compound.

   21. A composition as claimed in anyone of Claims 17 to 21, wherein the sequestering agent comprises ethylene dia mine tetraacetic acid and/or a water soluble salt thereof.

   22. A composition as claimed in anyone of Claims 17 to 21, wherein the builder salt is a zeolite.

   23. A composition as claimed in anyone of Claims 17to 22 also containing a bentonite clay.

   24. A process for bleaching which comprises contacting material to be bleached with an aqueous solution of a bleaching detergent composition com prising a peroxyacid compound and/ora water soluble saitthereof and a surface active agent, the composition being substantially free of (i) water soluble silicate compounas, (ii) organic activators for peroxygen compounds, and (iii) agglomerate parti cleswhich essentially comprise a mixture of an activator, a water-insoluble silicate compound and a nonionicsurfactant.

   25. A process as claimed in Claim 24, wherein the surface active agent is an anionic, cationic, nonionic, ampholytic orzwitterionic detergent.

   (26) A process for bleaching which comprises contacting stained andlor soiled material to be bleached with an aqueous solution of a granular bleaching detergent composition comprising:

   (a) a bleaching agent comprising a peroxyacid compound andlor a watersoluble salt thereof; and (b) at least one surface active agent selected from anionic, nonionic, cationic, ampholytic and zwitterionic detergents, the bleaching detergent composi- tion being substantially free of (i) water-soluble silicate compounds, (5) organic activators for peroxygen compounds, and (iii) agglomerate particles which essentially comprise a mixture of an activator, a water-insoluble silicate compound and a nonionic surfactant. 27. A process as claimed in Claim 24,25 or 26, wherein the bleaching agent comprises monoperoxyphthalic acid andlor a water-soluble salt thereof. 85 28. A process as claimed in Claim 24,25 or 26, wherein the bleaching agent comprises magnesium monoperoxyphthalate. 29. A process as claimed in Claim 26, wherein the bleaching agent also contains a peroxygen com- pound.

   30. A process as claimed in anyone of Claims 24 to 29, wherein the surface active agent is an anionic detergent.

   31. A process as claimed in Claim 30, wherein the anionic detergent is a linear alkyl benzene sulphonate.

   32. A process as claimed in anyone of Claims 24 to 31, wherein the composition also contains a sequestering agent.

   33. A process as claimed in Claim 32, wherein the sequestering agent comprises ethylene diamine tetraacetic acid andlor a water-soluble salt thereof.

   34. A process as claimed in Claim 32, wherein the sequestering agent comprises diethylenetriamine pentamethylene phosphonic acid andlor a watersoluble saitthereof.

   35. A process as claimed in anyone of Claims 22 to 34, wherein the composition also contains a detergent buildersalt.

   36. A process as claimed in Claim 35, wherein the builder salt comprises pentasodium tripolyphosphate.

   37. A process as claimed in Claim 35, wherein the builder salt comprises a zeol ite.

   38. A process as claimed in anyone of Claims 22 to 37, wherein the bleaching detergent composition also contains a smectite-type clay.

   39. A bleaching detergent composition substantially as herein described with reference to anyone of the Examples otherthan the comparative Example.

   40. A process for bleaching comprising contacting material to be bleached with an aqueous addition of a bleaching detergent composition substantially as herein described with reference to any one of the Examples otherthan the comparative Examples.

   Printed in the United Kingdom for Her Majesty's Stationery Office, 8818935, 2186 1 8996. Published at the Patent Office, 25 Southampton Buildings, London WC2A IlAY, from which copies may be obtained.