AU606501B2 - Liquid detergents - Google Patents

Description

AUSTRALIA 6065 PATENTS ACT 1952

I

Form COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int. C1: Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: Related Art: 9 0 *0 TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: UNILEVER PLC UNILEVER HOUSE

BLACKFRIARS

LONDON EC4

ENGLAND

Actual Inventor: Address for Service: 0 i GRIFFITH HACK CO., 601 St. Kilda Road, Melbourne, Victoria 3004, Australia.

Complete Specification for the invention entitled: LIQUID DETERGENTS The following statement is a full description of this invention including the best method of performing it known to me:- 1- C.3219 LIQUID DETERGENTS s** 59e The present invention is concerned with liquid detergent compositions which contain sufficient detergent S 5 active material and sufficient dissolved electrolyte to result in a surfactant structure within the composition.

Such compositions are sometimes referred to as 'internally structured' since the structure is due to primary ingredients rather than to secondary additives, such as 10 certain cross-linked polyacrylates, which can be added as 'external structurants' to a composition which would otherwise show no evidence of a structure.

Internal structuring is very well known in the art and may be deliberatly brought about to endow properties such as consumer preferred flow properties and/or turbid appearance. Many internally structured liquids are also capable of suspending particulate solids such as detergency builders and abrasive particles. Examples of such structured liquids without suspended solids are given in US patent 4 244 840 whilst examples where solid particles are suspended are disclosed in specifications EP-A-160 342; EP-A-38 101; EP-A-104 452 and also in the aforementioned US 4 244 840.

2 C.3219 Some of the different kinds of surfactant structuring which are possible are described in the reference H.A.Barnes, 'Detergents', Ch.2. in K.Walters (Ed), 'Rheometry: Industrial Applications', J.Wiley Sons, Letchworth 1980. In general, the degree of ordering of such systems increases with increasing surfactant and/or electrolyte concentrations. At very low concentrations, the surfactant can exist as a molecular solution, or as a solution of spherical micelles, both of these being isotropic. With the addition of further surfactant and/or electrolyte, structured (anisotropic) systems can form.

0:0. They are referred to respectively, by various terms such as rod-micelles, planar lamellar structures, lamellar droplets and liquid crystalline phases. Often, different 15 workers have used different terminology to refer to the structures which are really the same. The presence of a Isurfactant structuring system in a liquid may be detected by means known to those skilled in the art for example, optical techniques, various rheometrical measurements, 20 x-ray or neutron diffraction, and sometimes, electron *I microscopy.

S. One common type of internal surfactant stiucture is sometimes referred to as a dispersion of lamellar droplets (lamellar dispersion) These droplets consist of an onion-like configuration of concentric bilayers of surfactant molecules, between which is trapped water or electrolyte solution (aqueous phase). Systems in which such droplets are close-packed provide a very desirable combination of physical stability and solid-suspending properties with useful flow properties.

As used herein, the term electrolyte means any ionic water soluble material. However, in structured liquids, not all the electrolyte is necessarily dissolved but may be suspended as particles of solid because the total 3 electrolyte concentration of the liquid is higher than the solubility limit of the electrolyte. Mixtures of electrolytes also may be used, with one or more being in the dissolved aqueous phase and one or more being substantially only in the suspenrd solid phase. Two or more electrolytes may also be distributed approximately proportionally, between these two phases. In part, this may depend on processing, e.g. the order of addition of components. On the other hand, the term 'salts' includes all organic and inorganic materials which may be included, other than surfactants and water, whether or not they are ionic, and this term encompasses the sub-set of the electrolytes (water soluble materials).

The amounts and types of surfactants and salts builders, buffers, enzyme stabilizers, anti-corrosives) which ideally one would want to incorporate in such systems, will vary a great deal according to the type of product being incorporated, Unfortunately, this is hampered in some cases, by 20 incompatibility of components and one of the ways in which this can manifest itself is salting-out (precipitation) of the surfactants due to the salts present. This is particularly a problem where one or both of the salt and surfactant concentrations is 25 relatively high, although the precise onset of salting-out will depend on the nature of the materials in question. It is often (but not exclusively) a problem when the salts contain a high proportion of electrolyte.

This has given rise to a desire to identify surfactants and sufactant blends which can stably be incorporated in such liquids to endow an improved degree of tolerance of a wide range of types and concentrations of salts. This is essentially the problem addressed in patent specification EP-A-178,006, although the surfactants described there for this purpose (alkyl

V

4 C.3219 polycarboxylates) do not give the degree of electrolyte tolerance which the present invention seeks to provide.

Since many of the usual salts are also electrolytes, one may assume that suitable surfactants to give the required improvement could be identified by dissolving them in water and testing their tolerance to progressively increasing amounts of added electrolyte. Unfortunately, we have found that this is not always an accurate predictor. The reason could be due to the fact that an aqueous solution of surfactant will be a molecular solution or a solution of spherical micelles. This is quite different to the arrangement of the surfactant molecules in structured liquids. Thus, as electrolyte is 15 progressively added to molecular or spherical micelle solutions of surfactant, the behaviour of the surfactant will not always mimic that in the structured systems.

However, it has now been found that unexpectedly, 20 especially suitable surfactants (hereinafter called stabilising surfacants') can be identified usinig a test of the general kind referred to above, provided that it is framed in a suitable manner, provided that one defines an appropriate threshold for deciding whether a particular surfactant passes the test and provided one also ensures o that the composition containing the stabilising surfactant gives a certain result upon centrifugation. This provides the advantage that the surfactants may be screened for use in novel internally structured detergent liquids.

The test herein prescribed for electrolyte tolerance is termed the measurement of salting-out resistance. For this test, 200ml is prepared of a 5% by weight aqueous solution of the surfactant in question. Trisodium nitrolotriacetate (NTA) is added at room temperature (ca until phase separation, as observed by the onset of C.3219 cloudiness, occurs. The amount of NTA added at this point, as expressed in gram equivalents added to 1 litre of the surfactant solution (1 mol of NTA 3 equivalents) is the salting-out resistance of the surfactant. Where convenient, the abbreviation SOR will be used for salting-out resistance.

Thus, the present invention provides an aqueous liquid detergent composition comprising detergent active material and dissolved electrolyte in amounts sufficient to result in a surfactant structure within said composition, which composition yields substantially no '15 clear liquid active rich layer upon centrifuging at 750G for 20 hours at 25*C, wherein the detergent active S material comprises a stabilising surfactant, which has an average alkyl chain length greater than 6 carbon atoms, and which has a salting-out resistance (as hereinbefore defined), greater than, or equal to 6.4.

As compared with previously known surfactant structured liquid detergents, the selection of surfactants as described above allows the compositions of the present invention to be capable of greater flexibility in the incorporation of large amounts of salts, especially soluble salts electrolytes) and improved possibilities for the incorporation of polymer builders, especially water-soluble builders, which can also act to bring about a desirable viscosity reduction in the product. The incorporation of higher levels of surfactants is advantageous for fatty soil removal. In particular, where the stabilising surfactant is nonionic in character, the ensuing incorporation of high levels of nonionic rather than anionic surfactant is advantageous for the stability of any enzymes present, these in general being more sensitive to anionics than to nonionics. In general, the applicants have observed a trend that the higher the measured SOR, the lower is the 6 C. 3219 concentration of surfactant necessary to achieve a given advantage.

For a composition to be in accordance with the present invention, it is not only necessary for it to contain at least some stabilisinig surfactant as hereinbefore defined but also for the compositions as a whole to yield substantially no clear liquid active rich layer upon centrifugation at 750G for 20 hours at The abbreviation G refers to the value of the eat's normal gravitational. force. it should be noted that this requirement excludes compositions which do not demonstrate the advantage provided by compositions of the present invention and also those compositions which are the 15 subject of our co-pending patent application, reference 0 0 no.C.3218, entitled 'Aqueous Detergent Compositions and 0 Methods of Forming Them' filed on the same day as this 0 application.

0 0 20 In this context, the term 'clear' in respect of S. liquid active rich layer means totally or substantially 0 00 clear to the unaided eye. A liquid layer which is not active rich will contain less than 10% by weight of so4 surfactant (detergent active) material, preferably less than most preferably less than 2% by weight.

The 8tabilising surfactant may constitute all or part of the detergent active material. The only restriction on the total amount of detergent active and electrolyte is that together they must result in formation of a structuring system. Thus, within the ambit of the present invention, a very wide variation in surfactant types and levels is possible. The selection of surfactant types and their proportions, in order to obtain a stable liquid with the required structure will, in the light of the present teaching, now be fully within the capabilit y of those C.3219 7 Skilled in the art. However, it can be mentioned that an important sub-class of useful compositions is those where the detergent active material comprises one or more conventional or 'primary' surfactants, together with one or more stabilising surfactants. Typical blends useful for fabric washing compositions include those where the primary surfactant(s) comprise nonionic and/or a non-alkoxylated anicnic and/or an alkoxylated anionic surfactant.

The stabilising surfactant should have an average alkyl chain length greater than 6 carbon atoms, it is 15 usually preferred that the stabilising surfactant have an average alkyl chain length greater than 8 carbon atoms. Some especially preferred classes of stabilising surfactants which may be used alone or in combination S are:alkyl polyalkoxylated phosphates; alkyl polyalkoxylated sulphosuccinates; S* dialkyl diphenyloxide disulphonates; and alkyl polysaccharides (sometimes called alkyl polyglucosides or polyglycosides).

A wide variety of such stabilising surfactants is known in the art, for example the alkyl polysaccharides described in European patent specification nos.

074; 70 075; 70 076; 70 077; 75 994; 75 995; 75 996 and 92 355.

Especially preferred are those stabilising surfactants (of whatever chemical type) which have an SOR greater than In many (but not all) cases, the total detergent active material may b present at from 2% to 50% by weight of the total composition, especially from 5% to 35% and most preferably from 10% to 30% by weight. Thus, these 8 figures will apply both to blends of primary and stabilising surfactants, as well as to the case where the detergent active material consists entirely of stabilising surfactant. However, with blends of primary and stabilising surfactants, the amount of stabilising surfactant material will typically constitute from 0.1% to 45% by weight of the total composition, especially from 0.5% to 30% and most preferably from 1% to 30% by weight. In such blends, the stabilising surfactant will often constitute from 5% to 90% by weight of the total detergent active material, especially from 7.5% to and most preferably from 10% to 90% by weight, Generally, it is very desirable that the compositions should have a rheology and a minimum stability, compatible with most commercial and retail requirements. For this reason, we generally prefer the o compositions of the present invention to yield no more than 2% by volume phase separation upon storage at 25 0

C

for 21 days from the time of preparation and to have a 20 viscosity of no greater than 2.5 Pas, preferably 1 Pas at a shear rate of 21 s

I

In the case of blends of primary and stabilising surfactants, the precise proportions of each component which will result in such stability and 25 viscosity will depend on the typa(s) and amount(s) of the electrolytes, as is the case with the conventional structured liquids. Thus, by way of illustration, Figure 1 shows a schematic representation of a typical ternary stability diagram for a blend of dodecyl benzene sulphonate (DoBS), a C 1 2 1 5 fatty alcohol etnoxylated with an average of 7 moles of ethylene oxide, and a stabilising surfactant. Locus I illustrates the boundary of compositions which are stable at one electrolyte level (say 10% by weight). For this boundary, the broken lines A, B, C have the following meanings.

it- A Minimum weight fraction of stabilising surfactant with respect to the total surfactant level, to obtain a stable liquid detergent composition (here 0.06).

B Maximum weight fraction of ethoxylated fatty alcohol with respect to the total surfactant level, which can stably be incorporated (here 0.34).

C Minimum weight fraction of charged surfactant with respect to the total surfactant level (here 0.37), to obtain a stable liquid detergent composition (assuming the stabilising surfactant is nonionic in type).

Locus II shows the same boundary at a higher electrolye level (say 12.5% by weight). Thus, it can be appreciated that when determining compositional parameters at different electrolyte levels, it is necessary to change the proportions of surfactants so o that the test composition is always effectively in the same place relative to the stability boundary. Such 20 adjustments similarly have to be made in determining thet threshold levels A, B and C at different electrolyte levels, as will be shown hereinbelow by way of example.

In such ternary surfactant blends, the use of a stabilising surfactant as a co-surfactant together with 25 one or more primary surfactants leads to a larger stable area within the stability diagram a wider range of surfactant ratios result in stable compositions) than would be expected from the additive behaviour of the respective binary combinations. Figure 2 represents a system of 23% total surfactant, 10% sodium citrate and 67% water, the surfactants being dodecyl benzene sulphonate, C 1 2 1 5

E

7 and the stabilising surfactant

C

1 2 1 3

G

3 (see key at end of Example Ternary diagram a) shows the I C. 3219 expected additive behavious from the binary systewiz whilst diagram b) shqw,; the stability area found in practice.

N.B. in these diagrams, numbers alonq the axes denote the fraction of surfacta~nt with respect to the total surfactant in the composition.

The detergent active material in general, may comprise one or more surfactants, and whether in the primary or stabilising categories, may be selected from anionic, cationic, nonionic, zwitterionic and amphoteric speci-aa,~ and (provided mutually compatible) mixtures thereof. FQXr example, they may be chosen from any of the classes, subqlasses- an6 specific materials described in 'Sur--ace Active Agents~ Vol. 1, by Schwartz Perry, 15 Irterscience 1949 and '$urface Aqti!ve Agents' Vol.11 by Sobwartz, Perry Fpvch (Intersclence 1958), in the current edition of I McCutcheon, Is Emulsifiers Detergents"~ pu.bished by the McC'utcheon c4vision of Manufacturing Confectioners Company or in Iensid-Taschenbuch I, 20 H.Stache, 2nd Edn.t Carl H-anser Verlag, Munchen Wien, Zn the case of the prlmary surfactants, suitable nonionic types includes in particular the reaction products of compounds having a hydrophobic group and a U reac~ive hydrogen atom, for example aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethyloene oxide either alone or with propylen~e oidz. spE~aifc nonionic detergent compounds are alkyl (C 6 -C18 -tifi4ry or :secondary linear or branched alcohols with ethylene oxide, and products Mnade by condensation ot ethylene oxide wit~h th reaction products of propylene oxide and ethylenediamine. Other so-called nonionic detergent cL Ipounds include long chain tertiary amine oxides, long chaiin tertiary phospine oxides and dIalkyl suiphoxi-des.

I

11 C.3219 The primary anionic detergent surfactants are usually water-soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the termi alkyl being used to include the alkyl portion of higher acyl radicals.

Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially those obtained by sulphating higher (C8-C18) alcohols produced for example from tallow or coconut oil, sodium and potassium alkyl (C 9

-C

2 0 benzene sulphonates, particularly sodium linear secondary alkyl (C 1 0

-C

1 5 benzene sulphonates; sodium alkyl glyceryl ether sulphates, S especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived 15 from petroleum; sodium coconut oil fatty monoglyceride sulphates and sulphonates; sodium and potassium salts of o sulphuric acid esters of higher (C 8

-C

1 8 fatty alcohol-alkylene oxide, particularly ethylene oxide, reaction products; the reaction products of fatty acids S* 20 such as coconut fatty acids esterified with isethionic acid and neutralised with sodium hydroxide; sodium and potassium salts of fatty acid amides of methyl taurine; r alkane monosulphonates such as those derived by reacting alpha-olefins (C -C 2 0 with sodium bisulphite and those derived from reacting paraffins with SO 2 and C12 and then hydrolysing with a base to produce a random sulponate; and olefin sulphonates, which term is used to describe the material made by reacting olefins, particularly C 1 0

-C

2 0 alpha-olefins, with so 3 and then neutralising and hydrolysing the reaction product. The preferred anionic detergent compounds are sodium (Cl -C 1 5 alkyl benzene sulphonates and sodium (C16-C 1 8 alkyl sulphates, It is also possible to include, as a primary surfactant, an alkali metal soap of a fatty acid, especially a soap of an acid having from 12 to 18 carbon 12 C.3219 atoms, for example oleic acid, ricinoleic acid, and fatty acids derived from castor oil, rapeseed oil, groundnut oil, coconut oil, palmkernel oil or mixtures thereof. The sodium or potassium soaps of these acids can be used, the potassium soaps being preferred.

The compositions also contain electrolyte in an amount sufficient to bring about structuring of the detergent active material. Preferably though, the compositions contain from 1% to 60%, especially from 10 to S" 45% of a salting-out electrolyte. Salting-out electrolyte So*. has the meaning ascribed to in specification EP-A-79 646.

Optionally, some salting-in electrolyte (as defined in the latter specification) may also be included, provided if of a kind and in an amount compatible with the other components and the composition is still in accordance with the definition of the invention claimed herein. Some or all of the electrolyte (whether salting-in or salting-out), or any substantially water insoluble salt which may be present, may have detergency builder properties. In any event, it is preferred that e* compositions according to the present invention include detergency builder material, some or all of which may be electrolyte. The builder material is any capable of reducing the level of free calcium ions in the wash liquor and will preferably provide the composition with other beneficial properties such as the generation of an alkaline pH, the suspension of soil removed from the fabric and the disper(?in or the fabric softening clay material.

Examples of phosphorous-containing inorganic detergency builders, when present, include the water-soluble salts, especially alkali metal pyrophosphates, orthophosphates, polyphosphates and phosphonates. Specific examples of inorganic phosphate

I

C.3219 13 builders include sodium and potassium tripolyphosphates, phosphates and hexametaphosphates.

Examples of non-phosphorus-containing inorganic detergency builders, when present, include waterinsoluble alkali metal carbonates, bicarbinates, silicates and crystalline and amorphous alumino silicates. Specific examples include sodium carbonate (with or without calcite seeds), potassium carbonate, sodium and potassium bicarbonates, silicates and zeolites.

15 Examples of organic detergency builders, when present, include the alkaline metal, ammonium and substituted ammonium polyacetyl carboxylates and polyhydroxysulphonates. Specific examples include sodium, potassium, lithium, ammonium and substituted *'20 ammonium salts of ethylenediaminetetraacetic acid, nitrilitriacetic acid, oxydisuccinic acid, melitic acid, benzene polycarboxylic acids, citric acid, tartrate disuccinic acid and tartrate mono-succinic acid.

Apart from the ingredients already mentioned, a .umber of optional ingrediernts may also be present, for example lather boosters such as alkanolamides, particularly the monoethanolamides derived from palm kernel fatty acids and coconut fatty acids, fabric softeners such as clays, amines and amine oxides, lather depressants, oxygen-releasing bleaching agents such as tricloroisocyanuric acid, inorganic salts such as sodium sulphate, and, usually present in very minor amounts, fluorescent agents, perfumes, enzymes such as proteases and amylases, germicides and colourants.

I- 14 C.3219 The invention will now be illustrated by way of the following Exam~ples.

Not* '04S91 4..

00* *t 0 0 Example 1; Salting-out Resistance of Surfactants .0 41 Active detergent Salting-out Resistaripe Amount of NTA to get phase separation at room temperature of a 5% w,'w surfactant solution grams NTA grams added to equivalent 200 ml added to surfactant 1 litre solution surfactant solution Ethoxylated fatty alcohol, C 12 15

E

7 18.5-22 1.0-1.2 Alkyl ether sulphate, LE G 59 3.2 i ofLE S 74 o itLE 5S 59 3.2 to It LE 6S 48 2.6 Alkyl ether carboxylate, LE 2 5 C 59 3.2 LE 6985.

LE 6E 8 C 106 5.8 LE 8 C 106 5.8 Alkyl ether~ phosphate, C,.

21 E P 118 6.4 II I012- 15 EjQP 140 7.6 AlkyL ether sulphosuccinate, LE 2 2 SC >ca 180* >ca di si~diurn salt Alkyl ditmethy3. amine. oxide, LAO 116 6.3 Di C Idiphenyloxide disulphonate 170 9.2 =Dow~?ax 3B2 ex Dow Alkyl polyglucoside, C8-1002-6, ca 180* ca Alkyl polyglucoside >ca 180* ca Triton ft...

ft ft ft ft. ft ft eft ft ft ft ft ftft ft ft.

ft ft ft *ft* ft ft...

ft ft ft ft.. ft ft. ft ft ~ft ft ft ft.

16 1" Active detergent Salting-out Resistance Amount of NTA to get phase separation at room temperature of a 5% w/w surfactant solution grams NTA grams added to equivalent 200 ml added to surfactant 1 litre solution surfactant solution Alkyl polyglucoside., 09110 97 5.3 It I I C9_11G3 ca 180* ca 0,2t 1 0 tC 12-13G31 ca 180* ca C x alkyl chain length

S.

5 6O* S S S 55 0 S. S S

S*

L

X

S

E

Cy 25 P

G

Lauryl Sulphate Ethylene oxide chal Carboxy late Phosphate Glucoside units saturated with NTA, n length *0@S

S

5*

S

S.

S S

S

a.

5. 0 S. I a 17 C. 3219 Example 2 Surfactant. molecules ranked in order of their Salting:-out Resistanice.- Active detergent SOR g.equiv NTA/ litre Alkyl polyglucoside, C 12 13 G 1 0 Ethoxylated fatty alcohol, C 1 15E 71.0 1.2 0 12-1537 *1 6 22.

*Alkyl ether sulphxate, E 45 LE S C53 303 Alkyl ether cphophate, C 2LE C 3 .2 1 IIt125Elo7.

18 C. 3219 Active detergent SOR g.equiv NTA/litre Di-C 1 0 diphenyloxide disulphonate 9.2 Alkyl ether suiphosuccinate, LE 2 2 SC Alkyl poly glucoside, C 8 10 G 2 6 9.

(Triton BG-1O) 0~ :*a0 Alkyl. poly glucoside, C 9 11

G

3 C 12.1 GI 3 *Sao so so 0 -19 ::0 C. 3219 Example 3 M4aximum amount of dissolved electrolyte which can stably be incorpo~ated in compositions with varying salting-out resistance of a cosurfactant.

Compositions: Dodecyl Benzene Suiphonate Stabilising- Surf-actant 10% w/w Water

NTA

)90% w/w )added on top Co-Surfactant SOR, expressed Maximum amount pf NITA -which in gram equiv- can be stably irxorporated alents NTA at various added to I cosurfactant/DoBS ratio litre RTA added on top) is 8/2 6.5/3.5, 515 Ethoxylated fatty alcohol, C 115E71.-12000 2C Alkyl ether sulphate,

LE

3

S

Alkyl ether carboxylate, LE 4 5

C

Alkyl ether phosphate, C1 2 -1 E Alkyl poly gCcsie

C

12 13

G

3.2 5.1 6.4 27 382 >42* >32 ca. 9.5 >42* >42* saturated this table demonstrates: the higher the SOR of the cosurfactant, the more soluble salt can stzably be incorporated in liquid detergent formulations.

0 S 0.06 S 00 0 00 0 06 0005 00 0 0 0 so0 :40 J

V

20 C.3219 Example 4 Maximum amount of dissolved electrolyte which can stably be incorporated in compositions with varying salting-out resistance of the surfactant.

Compositions: DoBS or C, E P Ethoxylate a- ty alcohol, C12-15E7 10% Surfactant SOR, expressed in gram equivalents NTA added to 1 litre Water 90% added NTA on top Maximum amount of NTA which can stably be incorporated at vaiious surfactant/C 2_15E ratio.

NTA added on top).

8/2 6/4 4/6 DoBS 0.2* Alkyl ether phosphate, C 12 15 E5

P

6.4 >35 >35 estimated from phase diagrams This table demonstrates that with strong salting-out resistant surfactant molecules, large amounts of soluble salt can be incorporated in liquid detergent formulations.

C

C

C C C C a C *C Cd C C C.

CC. CCC S*C S C C C C S Ce CC C S S S C S C CC. eC C C A t 21 C. 3219 Examnple Electrolyte tolerance of compositions containing co-surfactant with varying Salting Out Resistance.

Compositions: Dodecyl Benzene Suiphonate Co-Sur factants 10 wiW Water )90% wfW NTA )added on top Co-Surfactant Co-Sr fatantSOR, expressed in grams equivalent NTA added to 1 .tLitre Maximum amount of NTA which can be stably incorpadded on top) Amount of CO surfactant to reach m~aximum amount of NTA, i. e:- C~o -surf actant 2t, total-surfactant Alkyl ether carboxylate LE 4.C 5.1 40 0.9 Alkyl ether phosphate C 6.4 ca 42* 0.8 Alkyl ether sulphosuccinae Lk SC ca 9.5 32 0.8 Alky! poly glucoside C 12 13

G

3 ca 9.5 >ca 42* 0.1 This table demonstrates: At high levels of incorporated NTA less cosurfactant is needed to obtain a stable liquid detergent on increasing salting-out resistance.

s-aturated.

U

3 3* 3 U 3 U 3.3 Us to 00 s* o:.0 3* *~of t 22 C .3219 Example 6 Ternary active liquid detergent formulations containing salting-out resistant active molecules.

Compositions: Dodecyl Benzene Suip'honate) Ethoxylated fatty alcohol, c125 E 7 10% w/W Co-surfactant121 7 Water 75, 65 or 55% wlw NTA 15, 25 or Co-Burfactan:- Minimum weight fraction of Maximum weight fraction* of co-surfactant ethoxylated fatty alcohol (wrt total surfactant) (wrt total surfactant) to obtain stable liquid- which can be stably weight frac.DoBS bracketed incorporated (wt fracn.

DoBS bracketed) NTA Level 15% NTA 25% NTA 35% NTA 15% NTA 25% NTA 35% NTA Alkyl ether sulphate, LE 3S Alkyl ether carboxylate,

LE..

5

C

Alkyl ether phosphate, C 12 15

E

5

P

Alkyl poly glucoside, C 12 13 G 3 0.2 (0.61 D.5 no stable 0.2 0 systems 0.1 0.3 0.7 0.4 0.1 (0.3) 0.1 0.4 0.4 0.5 0.4 0 6 (0.4) 0.1 0.2 0.2 0.4 0.2 0.2-0.3 (0.3) *see also Fig.l.

This table demonstrates generally that on increasing salting-out resistance of the co-surfactant: the amount of co-sur-factant necessary to get a stable syttem is descreasing the amount of ethoxylated fatty alcohol which stably can be incorporated is increased.

C U S 8.00 S a a 0 9 99 *9 9 938 0 23 00 *0 se we: .0* 64 to$*: C, 3219 E xamp le 7 Ternary acti-ve liquid detergent formulations containIng salting-out r esistant active molecules Compositions: Dodecyl Benzene Suiphonate) Ethoxylated fatty alcohol, C 12 15 E 7 23% wiw Co-surfactant Na-citrate 10 or 15% wlw Water 67 or 62% wlw 14 Stailising i;uztactant Minimum weight fraction* of Maxim-um weight fraction* of co-surfactant (wrt total ethoxylated fatty alcohol surfactant) to obtain (wrt total surfactant) a stable liquid-weight which can be stably frac. DoBS bracketed incorporated (wt. fracn.

DoBS bracketed) Na citrate level 10% citrate 15%, citrate 10% citrate 15% citrate Alkyl etlber-sulphate, LE 3S 0 0..2 0.3 0.1 (0.7) Alkyl poly glucoside, C 12 13 G3 0.1 (0.7) 0.4 (0.5) 0.3 see also Fig.l also stable compositions without cosurfa ctant.

This table demonstrates the same phenoizzena as Example 6.

3*S 3@

SC

3 53 00 0**a L5 53 5 4 OS 455 SO** S S S S 55 S @5 S 35 S 4 S ~S S 355 4* S Example 8 Ternary active liquid- detevgent formulations contair~ng salting-out reslistAntmrolacuiles.

Compositions: Dodecy'. Benzezie Suiphonate Ethoxylated fatty alcohol, C 12 15 7 'or C 12 15 E 3 .10% Co-surfac lant Borax w/w Glycerol

STP

Water 5 .0% 25.*0% balance.

Ethoxy.l~ted fatty alcohol Co-surf actant Maximum weight fraction* of nonionic detergent (wrt total surfactant levell which can be stably Incorporated Remarks C 12 15 E 7 None LE3

LE

4 5

C

0.3 0.3 0.7/0.3/- 0.,3 0.7/0,3/- 0.3 0.7/0.3/- 0.6 0.4/0.3/0.3 0.4 0,6/0,4/- *see also Fig. 1 Ethoxylated fatty alcohol only Ethoxylated fatty alcohol plus Alkyl poly glucoside Ethoxylated fatty alcohol only; incorporation of co-surfactant does not lead to increased level of nonionic detergent *wt ratio DOBS/ethoxylated fatty alcohol/ co-surf actant C 12 1 5

E

C 12 13 G 3 None C 5E3 C 1 2 1 3

G

3 >Q,5 L2) 0Q,5/0,3/0.2 Thifs table demonstrates *that with st~.bilising surfactant molecules which are nonionic in chrtrcter (C 12 3

G

3 stable formulations with a high. proportion of nonionic surfactants can be prepared.

25 Example 9 Demonstration of breakdown of a lamellar phase (and consequently no stabilisation of the corresponding detergent) when replacing C 1 2 1 5

E

7 by C 1 3 1 5

E

2 5 (in whole or in part) Compositions: Surfactants

NTA

Water 10% w/w 15% w/w 75% w/w Phases 4 C 1-5 53 LAS Co-.Surfactant a 1 5

E

7 LE S 1) C2 1

E

5 2 Stability 9g 0 0*

SS*

0S a. *0e0 0006 SS 6 *0 0 60 *4 S S *0 6 *6 0 0 *0 E~ 56 0 6 0eS 0 6 4 6 3 6 3 15 6 3 6 2 6 2 6 2- -2 L +LAM,

L

1

+LAM

L

1

+LAM

L+LAM

LAM

L

1

+LAM

L +AM

LAMI

L+LAM

L 1 4AM Unstable Uns tabl1e Stable Unstable Stable Stable Unstable Stable Stable Uins table Stable Stable Unstable 20 6 6 6 6 25 6 -3 4 -4 SOfl in q~ eq. NTA to I1 litre 1056 00 *0 0 *5 0 0 06 1) 3.2 3 0 Phases 2) 6A4 3) 2.1.

LI=active-poor~ isotropic phase L2=active-rich isotropic phase LAM =Lame2llar Liquid crystalline phase.

P I~ NOTE:- When replacing C~ 2 15

E

7 by more salting-out resistant surfactants, this may only lead to stabilisation when the lamellar phase (LAM) is not broken down to an active rich isotropic phase (L 2 This breakdown is demonstrated using C 13 15

E

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Claims (11)

1. An aqueous liquid detergent composition comprising detergent active material and dissolved electrolyte in amounts sufficient to result xn a surfactant structure within said composition, which composition yields substantially no clear liquid active rich layer upon centrifuging at 750G for 20 hours at 0 C, wherein the detergent active material comprises a stabilising surfactant, which has an average alkyl chain length greater than 6 C-atoms, and which has a salting-out resistance, greater than, or equal to 6.4.

2. A composition according to Claim 1, wherein the detergent active material also comprises a nonionic surfactant and/or a non-alkoxylated anionic surfactant and/or an alkoxylated anionic surfactant. c

3. A composition according to either preceding claim, wherein the stabilising surfactant is selected from:- alkyl polyalkoxylated phosphates; alkyl polyalkoxylated sulphosuccinates; dialkyl diphenyloxide disulphonates; alkyl polysaccharides; and mixtures thereof.

4. A composition according to any preceding claim, 2 wherein the stabilising surfactant, or at least one of the stabilising surfactants has a salting-out resistance greater than or equal to S:

5. A composition according to any preceding claim, wherein the stabilising surfactant has an average alkyl chain length greater than 8 carbon atoms. 3i br C.3219 27

6. A composition according to any preceding claim, wherein the detergent active material constitutes from 2% to 50% by weight of the total composition.

7. A composition according to any preceding claim, wherein the stabilising surfactant constitutes from 0.1% to 45% by weight of the total composition.

8. A composition according to any preceding claim, wherein the stabilising surfactant constitutes from to 90% by weight of the detergent active material. mm

9. A composition according to any preceding claim, 15 wherein the composition comprises from 1 to 60% by weight of a salting-out electrolyte, all or part of which constitutes said dissolved electrolyte.

10. A composition according to claim 9, wherein the 20 salting-out electrolyte constitutes fromi 10 to 45% by weight of the total composition. 4

11. A composition according to any preceding claim, which yields no more than 2% by weight phase separation 25 upon storage at 25'C for 21 days from the time of preparation and has a viscosity no greater than 1 Pas at a shear rate of 21s" 1 DATED THIS 6TH DAY OF FEBRUARY 1989 UNILEVER PLC By its Patent Attorneys: GRIFFITH HACK CO, Fellows Institute of Patent Attorneys of Australia