OA10060A

OA10060A - Detergent composition

Info

Publication number: OA10060A
Application number: OA60429A
Authority: OA
Inventors: Philip Richard Norman Eymond
Original assignee: Unilever Nv
Priority date: 1992-10-27
Filing date: 1993-10-27
Publication date: 1996-10-14
Also published as: GB9222538D0; IN179115B; GB2271998A; BR9304366A; ZA937999B

Abstract

Detergent products in semi-solid form, ie a gel, cream or paste, comprise from 10 to 45% by weight of non-soap detergent active, from 3 to 30% by weight of water-soluble salts at least part of which are detergent builders and from 25 to 87% by weight of water, which are characterised by a composition which generates a pH in the range from 7.0 to 9.8 when mixed with deionised water at a weight ratio of 1:99. The use of such a composition enhances stain removal. <IMAGE>

Description

C3487 110060 - ι -

DETERGENT COMPOSITION

This invention relates to· detergent compositions in seiri-solid form, that is to say a geI, cream or paste. Such a 5 detergent form is usually referred to as a "cream" and yet is usually sufficiently solid that it cannot be poured at.ambient températures. It. coheres together in a mass whichcan, however, be deformed by hand. Thus, this form isdistinct from liquids, powders and shaped solid forms such 10 as bars.

Such laundry detergent créants are marketed in sortiecountries for fabric washing and are frequently used in awashing procedure during which the fabric is in contact 15 with diluted detergent compositions for a relatively short time before it is rinsed.

Detergent active matériels hâve often been considered tofunction most effectively under alkaline washing 20 conditions. See for exemple Kirk-Othmer's Encyclopédie of

Chemical Technology, vol 22. page 390. Consequentlydetergent compositions are formulated so that when broughtinto contact with water an alkaline wash liquor isgenerated. Laundry detergent créants hâve followed this 25 general principle and commercial créants hâve contained alkaline salts so that when the cream is brought intocontact with water, the liquid formed by dissolution isalkaline. Typically sodium carbonate and/or sodiumsilicate is included to raise the alkalinity to a pH in 30 the range from above pH 10 eg. pH 11 or higher.

By contrast with the current practice of formulating forhigh pH we hâve now found that it is both possible andadvantageous to formuiate a detergent cream so that it 35 gives a reduced alkaline pH when placed in water. We hâve found that compositions with satisfactory structure and C3487 1 0060 integrity during storage can be made, even though theircontent of salts, especially strongly alkaline carbonateand silicate, is sufficiently low that when brought. intocontact with water a pH of 9.8 or less develops. 5

We hâve also found that in use of such compositions with arelatively short duration of contact between the dilutedcomposition and the fabric, formulation with lower pHleads to improved detergency against a range of stains, 10 even including some stains for which réduction of pH has been found not to be bénéficiai when using a differentproduct form and a longer duration of contact with thefabric. 15 Accordingly, the présent invention provides a detergent composition in semi-solid form comprising: (a) 10% to 45% by weighc of non-soap detergentactive ; 20 (b) 3% to 30% by weight of water-soluble salts, atleast some of which are detergency builders; (c) 25% to 87% by weight of water characterised in 25 that the composition generates a pH in the range from 7.0 to 9.8 when mixed with deionised waterat a weight ratio of composition: water of 1:99and allowed to dissolve as completely aspossible at a température of 20°C. 30

The percentages of detergent active and water solublesalts refer to the anhydrous material and do not includeany water t.aken up as water of hydration. 35 In practice the pH of a composition will not vary much with température, so that a pH value measured at any 1 0060 température in the range from 15°C to 30°C will beadequately accurate.

It is preferred that the pH, measured at 20°C as statedabove, lies in a range from 7.5 to 9.6. The pH may welllie above a lower limit of pH 8.0. Alternatively, or inaddition, it may lie in a range not exceeding pH 9.3 oreven pH 9.2.

In order to attain a lower pli than that which is conventionally obtained, the créants will desirably notcontain much, if any, water soluble carbonate nor watersoluble silicate, both of which are strongly alkaline.

In particular the composition may be formulated so as tocontain not more than 3% by weight of water solublecarbonate, or indeed not more than 3% by weight of bothwater soluble carbonate and silicate.

Depending on the intended pH other less alkaline salts maybe introduced to provide further control of the pH. Thusfor instance sodium carbonate may be at least partiallyreplaced with bicarbonate or borax.

In use, of course, the proportions of mixing with waterare not controlled and deionised water is not used.Nevertheless the pH which is generated in use will beadequately related to that measured under the statedconditions, since it is largely controlled by the salts inthe composition.

The water soluble salts in the composition may includephosphate builder salts which can help to buffer the pHwhich is developed on mixing with water. C3487 10060 - 4 -

Ancr.her opt.-,nai, although désirable, bature is toinco.-porate l'each, in part.icular sodiun sulphite, toenhance the lc,ndering performance. We lave found thatthis can be usti successfully in the pH r<nge specrfied by 5 <-his invention.

Materials useful i, compositions of this invention willnow be dis'ussed in-urn: 10 Détergent active

As already mei.tioned, tlo composition includes n-m-soapdetergent activa in an an-^unt from 10 to 45wt% of theoverall composit-on. It ii envisaged that the amoint willgenerally range figm 12 to x-0wt% and a particularly 15 envisaged range is -rom 15 te 50 wt%.

Detergent actives useable in tho preser.t invention may befound in the general classes of anionic, nonionic,amphoteric and zwitterioaic actives. Geierally, non-soap 20 anionic detergent active will be the main detergent active présent. If any other categories of detergent active areprésent, these will typicaily be in minor amounts relativeto the anionic detergent active. 25 Anionic detergent actives which are particvlarly envisaged for use in the présent invention are alkyl benzenesulphonates of formula

R-C6H„--SOjM 30 primary alcohol sulphates of formula

ROSOjM 35 and/or fatty acyl ester sulphonates of formula C3487 1 0060 RCH CO^1

I so3m 5 in each of which R is a primary alkyl group containing 18 to 22 carbon atoms preferably 10 to 18 carbon atoms, R1 ifprésent is a primary alkyl group containing 1 to 6 carbonatoms preferably 1 to 4 carbon atoms, and M is a cationsuch that the detergent active material is water soluble. 10

Other detergent actives which may be used include alkanesulphonates and ethoxylated alcohol sulphates. Ifnonionic detergent active is used it will generally beethoxylated alcohol. Fatty acyl alkanolamides may also be 15 employed.

It. is possible within the scope of the invention toinclude soap but it would generally be absent because itinhibits the formation of lather by the non-soap detergent 20 active. Consequent.ly it is preferred that if soap is présent at a.11, the amount of it does not exceed 2% byweight of the composition.

Water soluble salts 25 These may hâve a fonction in the composition, especially as a detergency builder or as a bleach. However, inertsalts such as sodium sulphate may also be présent. Theamount of water soluble salts is preferably at least 5% byweight of the composition and may well not exceed 20% by 30 weight.

Detergency builder

At least some of the water soluble salts are required tobe detergency builder salts. Preferred is 3% to 30% by 35 weight, better 3% to 20% by weight of an alkali métal orthophosphate, pyrophosphate or tripolyphosphate. Otherwater soluble builder salts are organic builders, eg. 10060 sodium nitrilotriacetate, sodium tartrate, sodium citrateand sodium carboxymethylsuccinate.

Tn addition to the use of water soluble builder, water-insoluble aluminosilicate ion exchanger, foi' examplezeolite 4A, may also be included.

Water insolubles

It is désirable to incorporate a soluble aluminium sait,such as aluminium sulphate into the composition togetherwith sufficient sodium silicate that insoluble aluminosilicate forms in situ in the composition. This isvaluable in enhancing the structure and stability of thecomposition. British patent spécification 2099013describes the analogous incorporation of such aluminosilicate into rigid bars.

Also, a water insoluble filler other than aluminosilicatemay be included in the composition·, this may be a claysuch as kaolin or bentonite.

We hâve now found that it is possible to obtain a satisfactory stability during storage, without unduehardness of the composition, by incorporâtingaluminosilicate by formation in situ and aLsoincorporating other water-insoluble filler in a weightratio lying in a range from 70:30 to 30:70.

The water-insoluble matériel other than aluminosilicate ispreferably clay so that the proportions of aluminosilicateto clay lie in the range 7:3 to 3:7. A preferred range is6:4 to 4:6.

The aluminosilicate, as mentioned above, is desirablyformed in situ in the composition by incorporating asoluble aluminium sait such as aluminium sulphate in the 10060 - 7 - composition and also sodium silicate. When aluminiumsulphate is used as the aluminium sait the amount ofaluminosilicate which for-ms is apprcximately equal to theweight of an aluminium sulphate from which it is formed,provided that there is sufficient sodium silicate to givecomplété conversion of the soluble aluminium sait into theinsoluble aluminosilicate.

Hydrotrope

It is known to incorporate hydrotrope into detergentcréants. Such hydrotropes include short chain alkylbenzene sulphonates such as sodium toluene sulphonate.Preferred, however, is urea. A considérable advantage of this invention is thatréduction of the pH of the composition leads to asurprising improvement in the stability of urea in adetergent cream.

Bleach

The water-soluble alkali. métal salts of those sulphur oxoacids which are reducing agents may be included in thecomposition as bleaches. Preferred is to incorporate from1 to 15% by weight. of such matériel., better at least 2% oreven at least 5% by weight.

Other ingrédients

The composition of the invention may also contain otherdetergent additives in conventional amounts. Suchadditives include antiredeposition agents such as sodiumcarboxymethyl cellulose, colouring materials, fluorescers,photobleaches, germicides, opacifiers, humectants such asglyceroL, perfumes and alternative bleaches. Enzymes mayalso be included, notably proteases, lipases and amylases. 10060

Production A semi-solid detergent composition can be produced byadding the constituents to tbe water which will be présentin the eventual composition, and rnixing. A suitable procedure is to heat ail the water, anddissolve it. in the water-soluble builder, other solidelectrolyte (if used) and sodium carboxymethy1 cellulose(if used) while rnixing under conditions of high shear.

When these components hâve dissolved, alkaline silicate(if any) is added, followed by detergent active andalkanolamine (if any). Finally the sulphite (orbisulphite or metabisulphite) , any fluorescer and perfumeare added.

The detergent actives should be fully neutralised beforethe sulphite bleach is added, to avoid décomposition ofthe bleach during manufacture. The sulphite is thereforeadded at. the end of the procedure.

In the examples which follow ail percentages are by weightunless stated otherwise.

EXAMPLES A number of creams were made in accordance with formulations as set out in the following TABLE 1. The pHgenerated by each formulation was assessed by dispersingit in deionised water at a concentration of 1.0% by weightîe a composition: water ratio of 1:99 by weight. Thedispersion was allowed to stand for long enough to allowail soluble materials to dissolve after which the pH ofthe dispersion was measured at ambrent room température of20°C (small variations in température will not effect thepH to any not.iceable extent) . 1 0060 TABLE 1 TEST CREAM COMPOSITIONS Product 1 2 3 4 5 Ingrédient % by weight Sodium alky.l benzenesulphonate 22 22 35 35 22 Sodium carbonate - 5 - 5 - Sodium alkalinesilicate (anhydrousbasi s) 3 3 2 2 3 Aluminium sulphate(anhydrous basis) 4 4 3 3 4 Kaolin 6 1 - - 1 Urea 1 1 1 1 1 Sodium pyrophosphate 6 6 6 6 6 Sodium sulphite - - - - 5 Water, minors etc. to 100 pH (1% dispersion) 9.1 10.4 9.3 10.1 9.2 A nurnber of cotton sheet test; cloths (250 by 375 cms) werestained with a variety of different stains on differentarea of the test cloth. The stains were red wine, banana,blackberry, grass, tea, coffee, coffee/milk, tea/milk andtea/milk/sugar.

The various creams were then used to wash the test clothsusing a standardised procedure comraonly used withdetergent creams.

The test cloth was immersed in a quantity of deionisedwater at a liquor to cloth ratio of 7:1. The wetted testcloth was squeezed out, reimmersed and squeezed out. asecond time and then treated with the test cream. Thecream was spread by hand on the cloth until the amount ofdetergent composition transferred to the cloth waséquivalent to 4% by weight of the dried cloth. The 1 0060 ίο treated test cloth was rubbed 40 times over a period of 30seconds. After th.is time it was squeezed and rinsed oncein clean, cold water.

The réflectance of each stained area of the test cloth wasmeasured at 460nm before and after washing. EXAMPLE 1

Assessments of stain removal

In this example, the stain removal of a cream according tothe invention (Product 1) was compared with a conventionalcream formulation containing sodium carbonate (Product 2} .The results in Table 2 demonstrate that the productaccording to the invention has improved stain removalcornpared to the conventional product. TABLE 2

Stain type Réflectance Change (R460) Product 1 Product 2 Red Wine 10.6 8.8 Banana 9.6 5.9 Blackberry 19.3 13.6 Gras s 20.3 16.0 Tea 7.0 2.9 Cof fee 1 3.6 8.1 Cof fee/Milk 20.7 18.4 Tea/Milk 13.2 5.7 Tea/Milk/Sugar 13 .9 8.6 C3 4 87 1 0060 - Il - EXAMPLE 2

Assessments of stain removal

This example also demonst-rat.es the improvement in stainremoval. of a composition according to the invention 5 (Product 3) compared to a conventional composition (Product 4). These products hâve a high percentage ofbranched chain alkyl benzene sulphonate. 10 TABLE 3

Stain type Réflectance Change (R460) Product 3 Product 4 Red Wine 8.6 7.3 Banana 18.5 15.1 Blackberry 5.9 3.3 Grass 22.1 16.1 Tea 5.4 3.4 Coffee 10.0 9.2 Coffee/Milk 22.9 21.9 Tea/Milk 10.8 8.9 Tea/Milk/Sugar 13.9 12.6 25 EXAMPLE 3

Assessments of stain removal

In this example the effect on stain removal of combininglow pH and the b.l each sodium sulphite was examined. 1 0060 12 -

Stain Type Réflectance Change (R460) Product 5 Product 1 Product 2 Mango 34.0 27.8 2 6.9 Coffee/Milk' 35.0 32.1 32.1 Banana 23.9 14.9 13.9 Tea/M.ilk 9.5 10.1 6.2 Rust 27.9 24.9 23.1 pH = 9.0 pH -9.0 pH = 10.2

It can be seen t.hat for four stains t.he presence of thebleach gave an added improvement. EXAMPLE 4

Assessments of stability

Samples of products 1 and 2 were stored at 30°C. Afterone week t.he product 2 had a noticeable srnell of ammoniawhereas product 1 did not, indicatirig that the lower pH ofproduct 1 was remarkably improving t.he stability of urea. EXAMPLE 5

Two sériés of composâtions were prepared. In each composition the basic formulation was:

Ingrédient % by weight Sodium alkyl benzene sulphonate 22 Sodium alkaline silicate } Aluminium sulphate } see below Kaolin } Urea 1 Sodium py r ophospha t. e 6 Wat er, minors etc balance l.o 100%

In these compositions the propoctionn of kaolin andaluminosilicates were varied. The quantity of sodium 1 0 0 6 0 - 13 - alkaline silicate was varied also to correspond with thequantity of aluminium sulphate. The compositions werebalanced to 100% by adjusting the weight of water. Inone sériés of compositions the total of kaolin andaluminosilicate was 7.5% by weight of the composition, inthe second set it was 12% by weight of the composition.

The compositions were cycled repeatedly between 20°C and30°C. After 20 cycles the compositions were assessed forthe extent of séparation on a scale from 0 to 5 asfollows: 0 = no change in appearance or mobility 1 = slight change in appearance or mobility 2 = some change but no liquid droplets visible 3 - some liquid visible 4 = layer of liquid on top of product 5 = deeper layer of liquid on product

Values up to 2 are satisfactory. The results were:

Total Kaolin and aluminosilicate: 7.5% 12% Kaolin : Al~Si ratio 100 : 0 5 3 80 : 20 3 2 60 : 40 2 1-2 40 : 60 1-2 0 20 : 80 1-2 0 . 0 : 100 1 0

Compositions without kaolin were sufficiently hard that itwas very difficult to scoop a portion out of a containerusing only the fingers (which is the general practice forremoval). Compositions without aluminosilicate were soft C3487 10060 - 14 and difficult to apply to fabric, especially the composition with 7.5% kao'Jin and no aluminosi1icate.

Compositions with a combination of both materials,especially in the range 70:30 to 30:70 better 60:40 to40:60 gave a good combination of handling properties andrésistance to séparation.

Claims

1 0060 - 15 - CLAIMS

1. A detergent composition in semi-solid formcomprising: (a) 10% to 45% by weight of non-soap detergentactive; (b) 3% to 30% by weight of water-soluble salts, atleast some of which are detergency builders; and (c) 25% to 87% by weight of water, characterised in that the composition generates a pHin the range from 7.0 to 9.8 when mixed withdeionised water at a weight ratio of composition:water of 1:99 and allowed to dissolve as completelyas possible at a température of 20°C.

2. A detergent composition according to claim 1 whereinthe water soluble salts comprise from 3% to 30% byweight (based on the whole composition) of adetergency builder which is an alkali métalorthophosphate, pyrophosphate or tripolyphosphate,optionally together with other water soluble salts.

3. A detergent composition according to claim 1 furthercomprising from 1 to 15% by weight of water-insolublematerial.

4. A detergent composition according to claim 1comprising from 5 to 15% in total water-insolublematerial consisting of aluminosilicate and othermaterial in weight ratio lying in a range from 7:3 to3:7. C3487 1 0060 16

5. A detergent composition according to daim 4 whereinthe ratio or aluminosilicate to other matériel is inthe range 6:4 to 4:6. 5 6. A detergent composition according to daim 3. further coinprising from 0.5 to 5% by weight. of hydrotrope.

7. A detergent composition according to daim 6 whereinthe hydrotrope is urea. 10

8. A detergent composition according to daim 1 whichdoes not contain more t.han 3% by weight of watersoluble carbonate. 15 A detergentthe pH lies composition according to daimin a range from 7.6 to 9.6. 1 wherein 20 10 A detergentthe pH lies composition according toin a range from 8.0 to 9 daim 9 wherein 3 .

11 . A detergent composition according to daim 1 including from 2 to 15% by weight of alkali métalsulphite, bisulphite or meta-bisulphite . 25 12. A method of washing fabrics comprising contacting the fabric with a composition according to any one of thepreceding daims, or a. tiquer formed by dilution ofthe composition, followed by nnsing the fabric aftera period of not. more than 5 minutes.