Detergent composition

This invention relates to a detergent composition, in particular to a detergent composition for washing fabrics.

Fabric washing compositions contain, as an essential ingrédient, a surfactant systern whose rôle is to assist in 5 the removal of soil from the fabric and its suspension in the wash liquor. Suitable detergent active surfactant materials fall into a number of classes, including anionic, nonionic and cationic materials. Marketed products contain materials selected from one or more of these classes»

The most widely used anionic surfactant materials are the alkyl benzene sulphonates and these provide satisfactory results especially at high températures. There has been a desire to find alternative anionic surfactants for use in circumstances when alkyl benzene sulphonates are undesirable.

Among such alternative anionic surfactants are the fatty acid ester sulphonates (FAES) of the general formula r¹ _ oh - COOR²

I SOjM

1 where R is an alkyl group derived from a fatty acid, usually from a natural source, R² is a short chain alkyl group, usually methyl and M is, for example, an alkali métal. Thus for example, United States patent 4416809 (Magari et al, assigned to lion Corporation) discloses a 25 composition containing FAES, soap and the salf of a polycarboxylic acid. Exemplified FAES materials are those

2 in which R is derived from tallow and R is methyl. Ethyl or propyl are also mentioned as possibilities for R .

<img file="OA9035A_D0001.tif" />

² 09035

We hâve found, however, that the performance of. such recommended FAES materials is unsatisfactory when the compositions also contain low HLB nonionic surfactants. Since the use of such nonionic surfactants has been shown to lead to a number of benefits, including an overall boosting in detergency (see GB 1241754 - Unilever), there is a desire to improve the performance of FAES materials in the presence of such nonionic materials.

We hâve now suprisingly discovered that this object can be achieved by the use of materials in which R²is butyl or higher alkyl.

Thus, according to the invention, there is provided a detergent composition including a surfactant System comprising:

i) a fatty acid ester sulphonate; and ii) nonionic surfactant having an HLB of less than 10.5 preferably less than 9.5;

wherein the fatty acid ester sulphonate has the general formula

R¹ - CH - COOR²

I so₃m where R¹ and R² are independently hydrocarbon groups having at least 4 carbon, atoms, the sum of the carbon atoms in groups R¹ and R² being from 8 to 30, and M is a monovalent cationic species.

The fatty acid ester sulphonate salts Of the above general formula can be produced from fatty acids in conventional manner. Désirable starting fatty acids are, for example, those derived from tallow, palm oil or coconut oil. Thus, it is preferred that the group R¹ contaips from

V

09035 to 18 carbon atoms. It may be fully or substantially saturated. The group R² may hâve fewer carbon atoms than the group R¹. For instance the group R² may hâve from 4 to 8 carbon atoms. In particular it may be butyl*

The sum of the carbon atoms in groups R¹ and R² will preferably lie in the range 12 to 24. It is préférable also that R¹ and R² are different, especially when the sum of the carbon atoms in groups R¹ and R² is 14 or more. A preferred FAES material is that in which R¹ is coconut alkyl and R² is 10 butyl.

Mixtures of FAES matériels as defined above could be used. Other FAES matériels, such as the tallow methyl material, may also be included in minor amounts, but there is no particular advantage in doing so.

It is preferred to use the water-·soluble salts of these anionic surfactants, specifically the alkali métal (sodium or potassium) salts thereof.

Suitable nonionic surfactants which may be used are the reaction products of compounds having a hydrophobie 20 group and a reactive hydrogen atom, for example aliphatic alcohols, acids, amides or alkyl phénols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Spécifie nonionic detergent compounds are alkyl (Cg - ^C22^ P^^enol^s“^et^yl^ene oxicl^e condensâtes, 25 the condensation products of aliphatic (Οθ - C^g) primary or secondary linear or branched alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine.

09035

When alkylene oxide adducts of fatty materials are used as the nonionic surfactants, the number of alkylene oxide groups per molécule has a considérable effect upon the HLB of the nonionic surfactant. The chain length and nature of the fatty material is also influential, and thus the preferred number of alkylene oxide groups per molécule dépends upon the nature and chain length of the fatty material.

We hâve found it of advantage that the weight ratio between the anionic surfactant and the alkoxylated nonionic surfactant lies between 4:1 and 1:4, most preferably between 3:1 and 1:2, otherwise the benefits of the invention may not be achieved.

P-referred compositions according to the invention include the surfactant system in an amount from 2% to ... 50%, such as from 4% to 30% by weight of the composition.

The surfactant System may include other surfactant materials in addition to the specified sulphonate and nonionic materials. These other surfactant materials may be selected from other anionic détergent active materials, zwitterionic or amphoteric detergent active materials or mixtures thereof.

<img file="OA9035A_D0002.tif" />

09035

Any suchfurther surfactant materials will generally be présent at a level which is no more than 50% preferably no more than.40% of the total amount of surfactant in the composition, and might be not over 5% of the whole composition.

The other anionic detergent active materials may be the usual water-soluble alkali métal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term 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 (Cg - Cjg) alcohols produced for example from tallow or coconut oil, sodium and potassium alkyl (Cg - C₂g) benzène sulphonates, particularly sodium linear secondary alkyl (Cio - C₁₅) benzene sulphonates; sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum; sodium coconut oil fatty monoglyceride sulphates and sulphonates; sodium and potassium salts of sulphuric acid esters of higher (Cg G^g) fatty alcohol-alkylene oxide, particularly ethylene oxide, réaction products; the reaction products of fatty acids such as coconut fatty acids esterified with

i.sethionic acid and neutralised with sodium hydroxide·; sodium and potassium salts of fatty acid amides of méthyl taurine; alkane monosulphonates such as those derived by reacting alpha-olefins (Cg - C_2Q) with sodium bisulphite and those derived from reacting paraffins with SO₂ and Cl₂30 and then hydrolysing with a base to product a random sulphate.

The compositions of the invention may contain a detergency builder material, this may be any material capable of reducing the level of free calcium ions in the wash liquor and will preferably provide the compositions

09035 with other bénéficiai properties such as the génération of an alkaline pH and the suspension of soil removed from the fabric.

Examples of phosphorus-containing inorganic'' detergency builders, when présent, include the water-soluble salts, especially alkali métal pyrophosphates, orthophosphates, orthophosphates, polyphosphates and phosphonates. Spécifie examples of inorganic phosphate builders include sodium and potassium tripolyphosphates, ortho phosphates and hexametaphosphates.

Examples of non-phosphorus-containing inorganic ' detergency builders, when présent, include watér-soluble alkali métal carbonates, bicarbonates, silicates ànd crystalline and amorphous aluminosilicates. Spécifie examples include sodium carbonate (with or without calcite seeds), potassium carbonate (with or .without calcite seeds), sodium and potassium bicarbonates and silicates.

Examples of organic detergency builders, when présent, include the alkali métal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates, polyacetyl carboxylates and polyhydroxysulphonates. Spécifie examples include sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediaminetetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, melitic acid, benzene polycarboxylic acids and citrie acid.

It is preferred that the compositions according to the invention be alkaline, that is at the concentration of g/1 in distilled water at 25°C the pH should be at least 8, preferably at least 10. To this end the

09035 compositions may include a water-soluble alkaline sait. This sait may be a detergency builder or a non-building alkaline material.

Apart from the ingrédients already mentioned, a number of optional ingrédients may also be présent.

Examples of other ingrédients which may be présent in the composition include fabric softening agents such as 10 fatty amines, fabric softening clay materials, lather boosters such as alkanolamides, particularly the monoethanolamides derived from palm kernel fatty acids and coconut fatty acids, lather depressants, oxygen-releasing bleaching agents such as sodium perborate and sodium percarbonate, peracid bleach precursors, chlorine-releasing bleaching agents such as tricloroisocyanuric acid, inorganic salts such as sodium sulphate, and, usually présent in very minor amounts, fluorescent agents, perfumes including déodorant perfurnes, enzymes such as proteases, cellulases, amylases and lipasé, germicides and colourants.

The detergent compositions according to the invention may be prepared by a number of different methods according 25 to their physical form. In the case of granular products they may be prepared by dry-mixing or coagglomeration. A preferred physical form is a granule incorporating a detergency builder sait and this is most conveniently manufactured by spray-drying at least part of the composition. In this process a slurry is prepared containing the heat-insensitive components of the composition such as the surfactant system, builder material and filler sait. The slurry is spray-dried to form base powder granules with which any solid heat-sensitive ingrédients may be mixed, such ingrédients including bleaches and enzymes. The specified nonionic

09035 surfactants can be liquidified by melting or solvent dissolution and sprayed onto the base powder granules, rather than including them in the slurry for spray-drying. The invention will now be described in more detail in the 5 following non-limiting examples.

EXAMPLES 1 TO 6

Wash liquors were prepared in water having a hardness 10 of 25° FH (équivalent to a free calcium ion concentration of 2.5 x 10³ molar). The wash liquor contained thé équivalent of 6 g/1 of a composition containing (by weight)

Specified anionic surfactant 9%

Specified nonionic surfactant 4% .

Sodium tripolyphosphate 23%

Sodium carbonate 6%

Sodium alkaline silicate 5.5%

Sodium sulphate 30.8%

Sodium chloride 2.93%

Water balance

The sodium chloride was included as being équivalent in ionic strength to 5%sodium perborate monohydrate which would be présent in practice. The bleach is left but of these experiments in order to avoid confusion between detergency and bleaching effect in the interprétation of the results.

³⁰

The wash liquors were used to wash a fabric load at a liquor to cloth ratio of50:1. The load included a number of polyester monitors to which had previously been applied - - 14 an amount of C tagged triolein. Measurement of the level of tagged triolein after washing, using standard radio-tracer techniques, gives an indication of the degree of detergency, ie. soil removal, obtained.

09035

The wash time was 20 minutes with an agitation of 70 rpm. Washes were isothermal at 40°C.

In each case the nonionic surfactant was either SYNPERONIC A7 (ex ICI) which is principally a C_iq/C_1RXo lu 5 alcohol ethoxylated with an average of 7 moles ethylene oxide per molécule having an HLB of 11.7, or a 1:3 by weight mixture thereof with SYNPERONIC A3, which is a similar material containing an average of 3 moles of ethylene oxide per molécule, the mixture having an HLB of 10 9.0.

The anionic surfactants used were:

CM: Coconut methyl FAES

TEXIN ES 68: A tallow methyl FAES ex Henkel

LB: C₁₂ alkyl butyl FAES

The results obtained were as follows:

<td> Example No</td><td> Anionic</td><td> Nonionic</td><td> % soil removal</td>

<td> 1</td><td> CM</td><td> A7</td><td> 20.1</td>

<td> 2</td><td> ES68</td><td> A7</td><td> 20.6</td>

<td> 3</td><td> LB</td><td> A7</td><td> 19.8</td>

<td> 4</td><td> CM</td><td> A7/A3</td><td> 26.0</td>

<td> 5</td><td> ES 6 8</td><td> A7/A3</td><td> 23.9</td>

<td> 6</td><td> LB</td><td> A7/A3</td><td> 36.2</td>

These results show that in the presence of the higher HLB nonionic material (Examples 1 to 3) there is very little différence between the anionic surfactants tested. In the presence of the lower HLB nonionic mixture (A7/A3) however, significant preference for the C^₂ butyl FAES over the others tested is évident.