CA1110516A - Detergent compositions - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A particulate alkaline detergent composition is made from over 15% to 50% of a partially neutralised alkali metal orthophosphate salt, from over 20% to 50% of an alkali metal carbonate salt and from 5% to 40% of a synthetic detergent surfactant. The compositions have good detergency properties in relation to the phosphorus content, especially at low phosphorus levels with over 15% to 30% of orthophos-phate salt, and the use of partially neutralised alkali metal orthophosphate avoids excessively high alkalinity.

Description

- 1 - cC.1016 .

DETERC~EN~ CO~IPOSITIONS

This invention relates to detergent compositions in particula-te form which are adapted for fabric ~ashing, and in particular -to such compositions containing a synthetic detergent surfactant together ~ith a phosphate detergency builder.
The most co~monly used detergency builders are the condensed phosphates, especially sodium tripolyphosphate, but it has been suggcsted that the use of phosphate detergency builders can contribute to eutrophication proble~s. There have been very many suggestions for alternative, mainly organic, materials to be used as detergency builders instead of the condensed phosphates, but most of these materials tend to be unsatisfac$ory for one reason or another, for example they are less efficient or biologically unacceptable, or they may simply be too expensive.

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2 _ ~C.1016 I-t has also beerl proposed to mi-tigate the problems of eutrophica-t-ion by using decreased Levels o:E condensed phosphatc detergency buildcrs, with or witllout the presence of o-ther dctergency builders, but few oi these proposals have approactle~d commercial accept~lce. ~lhus, when reduced leve]s of sodium -tripolyphosphate are used witllout supplemeIltal buildcrs, the~e can be considerable problems when using the compositions in hard water if there is insufficient phosphate to sequester all the calcium ions present. This causes -the precipitation of insoluble calcium phosphate salts which can be deposited on the washed fabrics, besides giving decreased detergency due to inadequate sof-tening of the wa-ter, sometimes accompanied by precipitation of insoluble calcium sal-ts o:E
anionic detergent compounds.
On the other hand, when a condensed phosphate builder is used with some non-phosphate detergency builders, the former may prevent the latter from functioning effectively~
especially in the case of other detelgency builders which act by precipitating the calcium salt, for example sodium carbonate. Moreover, there are relatively few other detergency builders which are completely acceptable environ-mentally and which are good enough to be worth using7 even in part replacement for a condensed phosphate builder.
In recent years a lot of e-ffort and expense has been directed to solving these problems, with the synthesis and evaluation of great numbers of new materials. ~owever~ it would inevitably ta~e several years for any completely new .
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- 3 ~ cC.10~6 material -to be clcared for domestic use, and therefore most recent in-tcrest has centered on known low and non-phosphate materials which act as builders by either sequestration, precipitation or ion-exchange and ~hich are known to be ellvLro~llentally safe.
~ ccording to one aspect o~ the present invention we have now found it possible to obtain effective detergency propcrties at reduced phosphate builder levels by using a partially neutralised alkali metal orthophosphate salt in combination with an alkali metal carbonate sal-t in defined proportions. As both of these materials are well known per se, there are no problems concerning environmental sa~ety, provided that the compositions do not give excessively alkaline solu~ions in use. Moreover, although both of the essential detergency building materials are so-called precipi-tant builders, that is they inactivate calcium hardness ions by forming insoluble calcium salts, the precipitate can readily be prevented from depositing on clothes at unacceptably high levels.
In a further aspect of the invention, particulate detergent compositions are provided which contain higher levels of partially neutralised alkali metal orthophosphate salts together with alkali me$al carbonate salts, which can be made with increased detergency building properties and yet with decreased energy consumption compared with otherwise similar compositions based on sodium tripolyphosphate.

...6 - ~ - cC.~16 The particlllate alkaline de-tergent co~npositions of the invent-;or are produced from over about 15% -to about 50% oE a partially neutraLised alkali metal orthophosphate salt" :Crom over .ibollt 20% to about 500~b oL` an a]kali metal carbonat;e saLt S antl :Crolll abou-t 5% to about ~U% of a synthetic detergent sur:Eactant, all these percen-tages being by weight oE the to-tal de-tergent composition. The degree of alkalini-ty of`
the detergent compositions should be such -that the p~ of a 0.1% aqueous solution of the composition is Erom 9 to 11.
It was proposed in our UK p~tent 1~4i2~40i to form detergent compositions comprising from 5% to 15% of ortho-phosphate salts and 20% to .450,b by weight oE al~aline salts, Eor e~ample sodium carbonate, in order to give a pH of at ,~
least ~.2 in use. These compositions were of particularly iS low phosphate content and also intended for use at low product concentrations. However, it transpired that such levels of phosphate were unnecessarily low for compliance with the legislation now expected to be enacted in several countries. In addition, at higher product concentra-tions, as commonly used in many European countries, the composi-tions of UK pa-tent 1,412,40i were less effective than desired in comparison with other higher phosphate compositions based on sodium tripolyphospha-te alone as a detergency builder. The present invention provides compositions of higher, ie over 15%~ phospha-te content, which have more effective detergency building properties.

~ ~ - cC.iO16 The partially neutralised alka]i metal orthophosphate salt uscd is either a potassium or preferably a sodium ortho-phosphate salt, as the latter are cheaper ~nd more readily available. ~-t :is preferred to -use so~e or all disodium S morlohydrogcn ortllopllosphate in the preparation o~ the oompo-si-tions, a'Lthough a proportion may be neutralised during powder pxocessing to form -the trialkali metal salt or some of the la-t-ter may also be present initially provided the p~ is not too high. ~lternatively, the mono- or mixed mono- and di-alkali metal orthophosphate salts may be used if desired to ~orm the compositions. Ii too much of the monosodium dihydrogen salt is used the pH can drop substantially, in which case some more alkaline material must also be added.
It may be advantageous to use as the source of the alkali metal orthophosphate salts a mixture of disodium and monosodium hydrogen orthophosphates in a molar ratio of about 1:3 to 2:3, especially about 1:2~ as such a mixture is commercially available, being produced as a feedstock in the manufacture of sodium tripolyphosphate, when it is known as ~'kiln-feed~'. This gives valuable cost savings because the energy otherwise employed to convert the ki'ln-feed into sodium tripolyphosphate is saved. The invention therefore includes a process ~or preparing the compositions of the invention in ~hich -the partially neutralised alkali metal orthophosphate salt used is a mixture of the mono- and di-sodium salts as described above.

, 5~6 _ 6 - cC.1016 The alkali metal orthophosphate salt used in the preparatioII of the detergent composi-tions may be in -the form O:e nnhyd:rous or hydrated salts, for e.Y~nple as disodium mono-hydrogell ortllophosphate dodccahyd.rate. It will be appreciated that hydr~tioll ox dehydration may also take place during de-tergen-t processing~ but the alnounts of the ortho-phosphate salts are calcu].a-ted in anhydro-us Iorm.
Whilst the ~nount of the alkali metal orthopbosphate salt can be varied generally within the range of over about 15/S to about 50%~ it is preferred to have a maxi~um or-tho-phosphate salt content of about 30% by weight, which corres-ponds to a ma~imum phosphorus content in the compositions of about 6% by weight. It is particularly preferred to have an alk.ali metal orthophosphate content of about 20% to 25%~ ie 15 about .4% to 5% phosphorus in the compositions. It will be appreciated that these levels of phosphorus are well below those which are cus-tomary when using sodium tripolyphosphate as the detergency builder, ie at levels which, until recently, were generally in excess of 30% of the compositions.
When higher levels of the alkali metal orthophosphate salts are used, especially within the range of about 30% to 50%, the compositions are particularly ~seful as so-called soaker/prewash compositions, when they are used at relatively low produc-t concentrations to aid in soil re~loval prior to ~5 normal washing. Otherwise they can be used as conventional fabric washi}lg compositions themselves, where high ~ater hardness levels are found and there are no phosphate eutro-' - 7 - cC.1016 phication prob:Lems. Use of the partially neutralised alkali metal orthophosphate salts preven-ts excessively high a].kal.:inity, especially wben higher levels o:E the orthophos~
phato 9 alt are prescnt.
The a.l.ka.l.i.llletal carbonate salt used is potassium or p.referably sodium carbonate or a mi.xture -thereof. The carbonate salt is preferably fully neutralised, but it may contain sorne potassiwn or sodium bicarbonate or sesqui~
carbonate.
Although -the amoun-t of the alkali metal carbonate salt can be varied between over about 20% to about 50% by weight of the compositions~ it is preferred to.use an amount of about 250,b to about 45C/o by l~eight depending on the type of ,.
composition to be produced. Lower levels of carbonate salt within the range of over about 20% to about 30% are normally used l~hen the higher levels of orthophosphate salt are employed. The amount of the alkali metal carbonate is determined on an anhydrous basis, although the carbonate salts may be hydrated either before or when incorporated 20 into the detergent compositions.
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The detergent compositions of the present invention necessarily include from about 5% to about ~0%~ preferably not more than about 257b, eg about 10% t 0 about 20% ~ by weigh-t . of a syntheti.c anionic, nonionic, amphoteric or zwitterionic detergent surfactant or a mixture thereof. It is particularly preferred to use a nonionic de-tergent surfactant either alone or in admixture with o-ther anionic detergent surfac-tants in 51~
- 8 - cC.1016 the case of low l~thering compositions. ~Iany suitable detergellt surfact~lts are commercially available c~ld are flllly descr-ibed ill the Literclture, for example in Sehwartz, l'erry ~ Berch in "Surface ~etive ~ents and Detergents~, VoLuules I ~nd :~:C.
The pre:f~xred nonionic detergent surfactants whicll m~y be used include in particu]ar the reac-tion products of eompounds having a hydrophobie group and a reactive hydrogen atom, for exal~ple aliphatie alcohols 7 aeids, amides or alkyl phenols with alkylene oYides, especially ethylene oxide ei.ther alone or with propylene oxide. Speeifie nonionie detergent surfaetants are alkyl (C6-C22) phenol-ethylene oxide condensates, generally 5 to 25 EO, ie 5 to 25 units of ethylene oxide per molecule; the condensa-tion produc-ts of aliphatic (C6-C18) primary or secondary linear or branehed aleohols with ethylene oside, generally 6 to 30 EO, and products made by condensation of ethylene oxide with the reaction produets of propylene oxide and ethylenediamine.
Other so~ealled nonionie detergent surfaetants include long eh~in tertiary amine oxides, long ehain tertiary phosphine oxides and dialkyl sulphoxidesO Mixtures of amine o~ides with ethoxylated nonionie eompounds can also be used.
~ he anionic detergent surfactants which ean be used are usually water-soluble alkali metal salts o~ organic sulphates and sulphonates having alkyl radicals con~aining from about 8 to 22 carbon atoms, the term alkyl being used to include the alkyl portion of higher acyl radieals. Examples of suitable s~

- ~ - cC.lOi6 sy~ltllct.i.c ani.v:rl:ic detergcnt surIactants are sodium ancl ~ota.q.qi.llm allcyl. sulr)l~ates~ ospecial~Ly tlloso obtained by slllpllatlTI~ h-i~llor (C~~C18) a:lcollol.s p:roduce(l :Eo:r e~ample lrom tnl:Low or COCOllllt o:i.l.; so(l~ m an(l potass:Lutn a].lcy:l. (C8-C20) l~oll~.otlo su:lpllorl;ltos, part:i.cularly HoclLum l:ln(~ar soconclary allcy l. (c~ O a l ~ onPello sulpllonates; sodium a~l~yl glyceryl other sulplllltes, ospoc:ial.:Ly thoso ethers o:E the higlter alcol~o:l.s do:r:i.vecl :lirolll tallow or coconut oil and syn-the-tic alcohols dorivetl from petroleu~; sodiuln COCollUt oil fatty ac:i.d monoglyccr:ide sulphates and sulphonates; sodl~ and potassi~ saltg O:e sulphuric acid esters o:~ higller (C8-C18~
I`atty a:Lcollol~a:lky:l.(3ne ox:icle, particularly e-thylene o~ide, roacl;:i.on prodtLcts; the reaction products of fak-ty acids s~ch as coconut :Latty acids esteri:eied with i.sethionic acic~
lS ~ncl nelltra:li.st~d with soclium hydrQx:Lde; sodium and potassillm salts o:E fatty acid ~nides of uletllyl taurine; allcane luono-sulphonates S~ICll as those derived by reacting alpha-oleEins (C8-C20) with sodiuul bisulphite and those derived by reacting p~aEfins with S02 and G12 and then hydrolysing with a base to produce a rando~L sulphonate; and olefin sulphonates, whiclt term is used -to describe tho material made by reacting ole.-Eins, parti.cularly C8-C20 alpha-olefins, wi-th Sn3 and then neutralising and hydrolysing~the reaction product. ~he pre:Eerre~l anionic de-tergent surfactants ~re sodiulu (ClO~C15) allcyl benY.ene sulphonates and sodium (Ci2-Ci8) all~yl sulp ~ mounts o:E ~llpho-teric or ~witterionic detergent surt`actants mly also be used iIl the COIllpOSitiOIlS o:E the - 1~ - cC.1016 inve:rltion but this is not normal].y desired due to their rel.atively high cost. Il' any amphoteric or zwitter:ionic doto.rgen-t surfac-t~nts are uscd it is gencrally in small amoullts in colnpos:itions based on the Inuch mo.re co~ only used syntllot:ic ~m:i.oll:io and/or nonioni.c de-tergent sur:Cac~ ts.
Solne soaps may also be used in thc compositions of the invelltion, but not as the sole detergen-t surfactants. Soap is particularly useful at low levels in binary and ternary mi,Ytures together with nonionic or mixed synthetic anionic and nonionic detergent surfactants, which have low sudsing proper-ties. The soaps which are used are -the sodium, or less desirably potassium, salts of C10-C2.4 fat y is particlllarly preferred tllat the soaps should be bascd ~ainly on the longer chain fatty acids wi$hin this range, that is with at least half of the soap having a carbon chai.n length of 16 or over. This is most conveniently accomplished by using soaps from natural sources such as tallow, palm oil or rapeseed oil, which can be hardened if desired, with lesser ~nounts of other shorter chain soaps, prepared from nut oils such as coconut oil or palm ~ernel oil. The amount of such soaps can be varied between about 0. 5% and about 255b by weight, with lower amounts of about 0. 5% to about 5% being generally sufficien-t for lather control. ~mounts of soap between about 2% and about 20%~ especially between about 50/b ~5 and about l50,b, are preferably used to give a beneficial effect on detergency.

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5~6 cC.1016 ~ part rrom -tlle de-tergent surfactants ancl detergency buildcrs, the detergent compositions O:r the invention c~n contaill any oL the conventional additives in the c~mounts in ~YhlCIl SllCl~ mat~rials are norlllally employed :in l`abric washin~
detergetlt colnpositions. Ex~nples of thesc additives include Lather boosters such as alkanola~nides, particularly the mono-ethanolantides derived from palm kernel fatty acids and coconut fatty acids, lather depressants such as alkyl phosphates, w~xes and silicones, antiredeposition agents such as sodium carboxymethylcellulose and polyvinyl pyrrolidone, oxygen-based bleaching agents such as sodium perbora-te and sodi~n percarbonate, per-acid bleach precursors, chlorine-releasing bleaching agents such as ~trichloroisocyamlric acid and alkali metal salts of dicllloroisocyanuric acid, fabric softening agents, inorganic salts such as sodium sulphate and magnesium silicate, and, usually present in very minor amounts, fluorescent agents, perf-~es, enzymes such as proteases and amylases, germicides and colourants.
I-t is particularly beneiicial to include in the detergent compositions -an amount of sodium percarbona~e, preferably be-tween about luok and about .40%~ for example about 15% to about 30%, by weight of the compositions. It has been found that tha efficiency of sodium percarbonate is increased in these compositions. Moreover, after the sodium percarbonate has lost its oxygen in use, the residual sodium carbonate call contribute to the reserve all~alinity of the wash solution.

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I-t is desiral~le to include one or more antideposition a~en-ts in -the detergent compositions of the i.nvention, -to dec:rease a tendellcy to forlll i.norganic deposi.ts on washed :Cal)rics . rrhe mos t cffective antideposit:ion agents are an:ionic polye lcc-trolytes, especially polyme:ric aliphatic carboxylates whi.ch appoar to stabilise the suspensions of insoluble calcium sal-ts and thereby inhibi.t their deposition onto fabrics. The amount of any such antideposition agent .
is normally :Crom about 0.05~0 to about 50lh by ~eight, preferably from about O.i% to about 2~ by weight of the compositions.
Speciïic preferred antideposition agents are the alkali metal or amlllorliuill, preferably sodium salts of homo- and co-polymers of acrylic acid or substituted acrylic acids, such as sodium polyacrylate, the sodium sal-t of copolymethacryl-amide/acrylic acid and sodilml poly-alpha-hydrogyacrylate, salts OI copolymers of maleic anhydride wi-th ethylene, vinyl-methylether or styrene, especially 1:1 copolymers, and optionally with partial esterificati.on of the carboxyl groups. Such copolymers generally have molecular ~eights in the range of about 2,000 to 500,000. Other antideposition agents include the sodium salts of polymaleic acid, polyita-conic acid and polyaspartic acid, phosphate esters oï ethoYy-la-ted alipha-tic alcohols, polyethylene glycol pllosphate esters, and certain phosphonates such as sodium ethane~
hydroxy-1, 1-diphosphonat e, s odium ethy lenedi amine t etra-niethylene phosphonate, and sodium 2-phosphonobutane tricarboxylate. ~Iixtures of organic phosphonic acids or , :

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~ 13 - cC.1016 substituted acrylic acids or their salts with protective colloids such as gelatin as described in Netherlands Appl-.i.cat:ion ~6020S2 may also be used. ~he most preferred cmtidcpositiorl agent is sodium polyacrylate hnving a ~ of out 10,000 to 5~,~00, ~or example about 20,0~0 ~o 30,000.
It is also poss:i~le to inc].ude in the deter~ent composi.tions O:e the invention minor amounts of other phosphate or non~phosphate detergency builders, which latter may be ei-ther so-ca~led precipitant builders, sequestran-ts or ion-exchange builders. Low levels of alkali metal tripoly-phosphate or pyrophosphate may be present with the alkali metal orthophosphate as impurities, for example c~t levels up to about 5~ by weight, but it is preferred not to have them present in thc compositions. The presence of other non-phosphate det~rgency builders may be benefioial, when it isdesired to increase detergency whilst using relatively low levels of the alkali me-tal orthophosphate and without using excessively high alkali metal carbonate levels, because of the high alkalinity this would otherwise cause. Exa~lples of 2~ such other detergency builders which could be used in these circumstances are amine carboxylates such as sodium nitrilo-triacetate, and sodium aluminosilicate ion-exchange materials, eg ~eolites A and X. However, such other detergency builder materials are not essential and it is a particular benefit of .5 the compositions of -the invention that satisfactory de-tergency building properties can be achieved with -the mixed alkali metal orthophosphate and alkali metal carbonate .

5~L6 ~ cC.10~6 builder salts at lower pllosphate levels than hitll~r-to considered necessary without other non-phosphate detergency bui'lders.
I-t is ~lso generall~ desi.rable -to include in -tlle clctox~cn-t compositions an amoun.t o:t' an all~ali metal sl'.l.icate, particularly sodium or-tho-, meta- or preEerably neutral or alkalille silicate. l'he more highly alkaline ortho- and meta-silicates are normally only -used at lower levels, in admixture l~i-th the neutral or alkaline silica-tes.
The presence of such alkali metal silicates, usually at levels oI from about 50,b to about 15% by weight of the compositions, is advantageous in decreasing the corrosion of metal parts in washing machines, besides giving processing 1' benefits and generally improved powder properties. Eowever, the presence of the allcali metal silicates in the compositions - of the invention can contribute to increased inorganic deposits on washed fabrics, and it is therafore preferred to use only low levels of.such silicates, if any, for eYample~not - more than about 10% by weight of the compositions.
The compositions of the invention are required to be al~aline, but not too strongly alkaline, as this could result in fabric damage and also be hazardous for domestic usage. ~' In practice the compositions should give a pH of from 9 to 11 - in use in aqueous wash solu-tion. It is preferred in particular for domes-tic products to have a minimum pH of a-t least about 9.25 a~d especially a pH of about 9.5 or over, as . .

lower pHs tend to be less effective for optimuul detergency - ~5 - cC.10~6 building, .~1d a m~im~n plI of about 10.5. ~he p~
should be measuJed ~-t the lowest normal usage concentration ol 0.1~ w/v O:e thc product in wator of 12I-I (Ca) (French per~ ont hardnoss, calcium only) at 50C, so -tllat a s~ltisL~ctoxy do~rçc oE alka:Linity c~ be ass~rcd in use at all norma:l procluct concentrations. ~he pH of the cletergent colllposltions in use is controlled by the amount and type of the par-tially neutralised alkali metal orthophosphate and alkali metal carbonate used, and on the other alkaline salts which may be present, silch as alkali me-tal silicate and sodium perbora-te or sodium percarbonate. It will be appreciated that because of the high a]kalinity of the compositions of the invention the other ingredients in the compositiolls should of course be chosen for their alkaline i5 stability, especially for pH-sensitive materials such as en~symes.
~ he detergcnt compositions of the present in~ention are required to be in particulate form, which includes powders and granules, and they may be made by conventional techniques.
for eYample by granulation or by slurry m~ing and spray drying processes. Dry mi~ing of the ingredients can also be used, especially for products to be sold in individual dose packs such as sachets, but this is not recommended for products sold in bulk for the consumer to dispense in use, because of potential segregation problems and because of the less uniform appearance of the products. I-t will be appreciated that if production of the detergent composi-tions - 16 - cC . 10~6 is conducted in the presence of moisture, the ingrediellts may reac-t together, for example the partially neutralised a].kali metal orthopllospllate salts may be f-urther neu-tralised by other more alkali.ne ingredi.ents present.
B 'rhe .invcnt:ion is illus t.rated by the :Eollot~ing 13xalllples in wllich parts and percent ages arc by ~,lci.ght, the amoullts o:E
the ingredients being eh~pressed on an anhydrous basis, except where o-therwise indicated.
Examples 1 and 2 ~ particulate detergent composition was prepared by slurry malcing and sp:ray drying -to the following nominal formulat iOll: ' ~;_edient o/0 C12-C15 alcohol - 8 E0 lO . 0 Disodium orthophosphate 20. 0 Sodium c arbonat e 35 . 0 Sodium percarbonate2 25 . 0 Sodi-um carboxymethylcellulose :1. 5 Sodium polyacrylate .1. 0 Sodium alkyl pho.sphat e 0 . 5 Fluores cent agent 0 . 5 Water to 100. 0

4% of the nonionic detergent surfactant ~as included in the spray dried powder and the remaining 6% was sprayed onto the finished product.
2 ~dded after spray drying.

.' , - 17 - cC.1016 This comp~sition (Example 1) was tes~ted for detergency at a product concelltra-tion oE o.~o/O in water of 25H
(c~ r~ ) a-t ~5C and showed equality with a comlllerci.ll ~roduct contailling 3~% sodium tripoLyphos~phatc.
S 'rho po~der was also cx~ninecl for inorganic deposi-tlon aCter mllltiple wash cycles. The latter tests were also done in an alltolllatic (rotating clrum) washing luachine at a product collcentration of 0.6% in 35H water (Ca~:Mg~ :1) at 95C
using natura]ly soiled wash loads wi-th test cloths. The results after iO wash cycles showed an inorganic deposition level of l.S%"ihich co~lpared favourably with that (2.2~ob) for a col~parative commercially available sodi~ tripolypllos-phate-built product. ~Iter 20 wash cycles the figures were, respectively, 3.3% and 4.90,b~ which still showed a1uarked benefit for -the composition of the invention despite its high conten-t of precipitant builder salts. The same test cloths were also examined for soil redeposition from the naturally soiled clothes, by measuring the change in light reflectance after both 10 and 20 wash cycles, when it was found that the product of the invention gave significantly less redeposition than the comparative commercially available product.
~ further powder (E~ample 2) was prepared with a similar formulation but with the nonionic surfactant level decreased from 10% to ~% and wi-th 6% sodium alkyl benzene sulphonate added instead. I~ addition 3/0 of sodium tallow soap was added and the amount of sodi-um percarbonate correspondin-gly decreased to 22%. This composition was ~lso found to have

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- 18 - cC.10~.6 good :Cabric waslling and bleaching properties despi-te -the low phosphate contcnt.
Both colllposi.ti.ons wele superior to the comltlerc:ial. sodilmi -tr3.po:Lyphospllate_b~lilt product in blcaching tea-stn:i.1letl test 5 clotlls, the increuse in ligllt ro:Electance being 6.3 arld 8.2 units ~reater for Exalllples 1 and 2~ respec-tively.
~xamples 3 and .4 Two compositions were made by dry mixing the ingredients to the sa~le formula as Example 1 except -that the amount of disodiwll orthophosphate was increased to 25% ancl 30%~
. respectively, and the amount of sodium carbonate was decreased -to 30,/0 and 25%~ respec-tively, in Examples 3 and ~.
The products were evaluated for fabric washing properties in a Terg_0_Tolueter against the product o:E Example 1, a first lS con-trol formulation containing only 10% of the disodium or-thophospha-te and 450,h of the sodium carbona-te but otherwise being the same as Examples 3 and .4, and a second control formulation containing 30% sodium tripolyphospha~e as detergency builder with 25//o sodium perborate, at .4 g/l in water of 25H at 80-85C. The products of both E~amples 3 and 4 were found to have slightly better detergency properties on artificially soiled test cloths compared with Example 1, significantly better detergency than the first control product and significantly improved bleaching 25 properties compared with the second control product.

5~6 - 19 - cC.lOi6 Ex~nples 5 to 7 The formu]ations of Examples 3 and 4 were varied by fiIst:Ly changing the sodium percarbonatc of Ex~llple 3 for sodi~ per~orate (Ex~nple 5), secondly by cllal1ging th0 10%
~5 nollio~lio sllr;l~lctclllt in Exa~ple 4 I`or 6% so~liuul alkyl benzene stl:lpllonate a~ 1% 0~ tbe same nonionic detergent suriactc~t (Exatllple 6), and thirdly by changing the 10% norlionic surfactarlt in Ex~lple ~ for 10% of sodium alkyl benzene sulphona-te and also challging the disodium orthophosphate and sodium car~on~te levels to 15.5% and 400,b, respectively ~Ex~lple 7~. The products were evalua-ted for detergency and bleaching properties in a Terg-0-Tometer c~nd again found to give good results. Ilowever, the use of the perbor~te in Ex~llple 5 was found -to give marginally less beneficial ~leaching on the test clo-th and the lowering of the nonionic surfactant level in Exaulple 6 was found to give slightly lo~er ~ut still good detergency results. ~he product o~
Example 7 was found to have very good detergency properties despite its low phosphorus level, when evaluated against a similar product con-taining 30/~o of sodium tripolyphosphate as the de-tergency builder.
Examples 8 to 10 Three products ~ere made to the same formulations as for Examp1es ~, 3 and 4, respectively, except that the 25 disodiwn orthophosphate was replaced by kiln-feed, ie mixed disodium and monosodiwllllydrogen phospllates (ratio about 1:2).
Evaluation tests sho~ed the products of Ex~nples 8 to 10 gave ' , 5~6 - 20 - cC.1016 wash solutions of lower p~I (0.3-0..4 units) compared with Exalllples i, 3 cmd .4. ~part from thi.s there was a directional benel`it but not a sigllil'ic~qn-t chaMge in detergency on US:illg tho l~iln-:Ceod instead o:~ the d:isodiulll orthophosphate.
~x~tlp:Les ll to 13 ~ detcrgent colllpositi.on (~AYample ll) was made by dry mi.~ing to the same l`ormulati.on as E,~ample l, excep-t or the omission of the sodiu~l polyac:rylate. To this COIupOSitiOll was added either 1.0% of sodil~u copoly(i:l)vinylmethylether-maleate (in Ex~uple 12) or 1.0% of sodium polyacrylate (~
~25,000) (in Example 13). The levsl of i.norganic deposi-ts on COttO11 terry towelling was then determined in coJnparison with the control formulaticn containing 30/O sodi~un tripoly-phosphate and 25% sodiulu perborate with the Iollowing 15 results (product dosage 6 g/l în 35H water at 80-85C):
% deposits Example 5 s~ashes l0 s~ashes 20 wash~s ll 4.2 8.0 10.. 4 12 1.3 2.0 . 2.5 13 1.2 2.3 2.
Control 0.6 2.8 3.6 These results show the beneficial results of incorporating an antideposition agent in the products acGording to the invention.

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Claims (18)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A particulate alkaline detergent composition produced from over about 15% to about 50% of a partially neutralized alkali metal orthophosphate salt, from over about 20% to about 50% of an alkali metal carbonate salt, and from about 5% to about 40% of a synthetic detergent surfactant, all these percentages being by weight of the total detergent composition.

2. A composition according to claim 1, wherein the partially neutralised alkali metal orthophosphate salt is disodium monohydrogen orthophosphate or a mixture thereof with monosodium dihydrogen orthophosphate.

3. A composition according to claim 2, wherein the partially neutralised alkali metal orthophosphate salt is a mixture of disodium and monosodium hydrogen orthophosphates in the molar ratio of about 1:3 to 2:3 parts, respectively.

4. A composition according to claim 1 comprising not more than about 30% by weight of the partially neutralised alkali metal orthophosphate salt.

5. A composition according to claim 4 comprising about 20%
to about 25% by weight of the orthophosphate salt.

6. A composition according to claim 1 comprising from about 30% to about 50% of the orthophosphate salt.

7. A composition according to claim 1, wherein the alkali metal carbonate salt is sodium carbonate, sodium bicarbonate or a mixture thereof.

8. A composition according to claim 1, wherein the amount of alkali metal carbonate salt is from about 25% to about 45% by weight of the composition.

9. A composition according to claim 8 comprising from about 20% to about 30% of the alkali metal carbonate salt.

10. A composition according to claim 1 comprising from about 5% to about 25% of a nonionic detergent surfactant.

11. A composition according to claim 1 comprising from about 0. 5% to about 25% by weight of soap.

12. A composition according to claim 1 comprising from about 10% to about 40% by weight of sodium percarbonate.

13. A composition according to claim 1 comprising not more than about 10% by weight of sodium silicate.

14. A composition according to claim 1 comprising from about 0.05% to about 5% by weight of an antideposition agent.

15. A composition according to claim 14, wherein the anti-deposition agent is a polymeric aliphatic carboxylate.

16. A composition according to claim 15, wherein the polymeric aliphatic carboxylate is an alkali metal or ammonium salt of a homo- or co-polymer of acrylic acid or a substituted acrylic acid.

17. A composition according to claim 1 comprising not more than about 5% by weight of alkali metal tripolyphosphate or pyrophosphate.

18. A composition according to claim 1 having a pH in 0.1%
aqueous solution of from about 9.25 to about 10.5.