EP0328361A2

EP0328361A2 - Detergent composition

Info

Publication number: EP0328361A2
Application number: EP89301194A
Authority: EP
Inventors: Michael Hull; Dennis Giles; Reginald Vear Scowen
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1988-02-10
Filing date: 1989-02-08
Publication date: 1989-08-16
Also published as: AU2967789A; OA09232A; BR8900558A; GB8803039D0; JPH01247496A; ZA891066B

Abstract

A detergent composition, especially for washing fabrics, comprises an anionic surfactant, a mixture of nonionic surfactants having an HLB above and below 10.5 and from 1% to 4% of a fatty acid (eg. coconut) monoethanolamide to improve oily soil removal.

Description

This invention relates to a detergent composition, in particular to a detergent composition for washing fabrics.
Fabric washing compositions contain, as an essential ingredient, a detergent active system whose role is to assist in the removal of soil from fabric and its suspension in the wash liquor. Suitable detergent active materials fall into a number of classes, including anionic and nonionic materials.
It is known to include in such detergent active systems an anionic detergent active material such as an alkyl benzene sulphonate and a mixture of nonionic detergent active materials. The latter can be classified according to their HLB and proposals have been made in the art to use a mixture of a high or medium HLB material with a low HLB material to provide detergency benefits, especially at low temperatures.
Such a composition is disclosed in, for example, British patent specification GB 1241754 (Unilever Limited/Gilbert).
We have now discovered that the performance of such a composition particularly in terms of oily soil removal can be further improved by the addition of an amine oxide.
Thus according to the invention there is provided a detergent composition which comprises a detergent active system comprising:

i) an anionic detergent active material;
ii) a nonionic detergent active system which is a mixture of a nonionic detergent active material with an HLB above 10.5 and a nonionic detergent active material with an HLB below 10.5; and
iii) an amine oxide having at least one alkyl or alkenyl chain containing from 9 to 22 carbon atoms.

Preferred compositions according to the invention include the detergent active materials in a total amount which is from 2% to 50%, such as from 7.5% to 30% by weight of the composition.
The amount of the anionic detergent active material is preferabiy from 4.5% to 18%, such as from 6% to 12% by weight of the composition. The higher HLB nonionic material may be present at from 0.5% to 4% by weight and the lower HLB material at from 1.5% to 6%, most preferably from 2% to 4% by weight. The amine oxide is effective from 1% to 4% preferably 1 to 2% by weight of the composition. The ratio of the anionic to nonionic surfactants may be from 5.5:1 to 1:1.2, preferabiy from 2.25:1 to 1:1. The amount of amine oxide is preferably equal to or greater than the individual amounts of each of the two said nonionic materials.
The anionic detergent active materials may be the usual water-soluble alkali metal salts of organic 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 (C₉ - C₂₀) benzene sulphonates, particularly sodium linear secondary alkyl (C₁₀ -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 (C₈ -C₁₈) fatty alcohol-alkylene oxide, particularly ethylene oxide, reaction products; the reaction products of fatty acids 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; alkane monosulphonates such as those derived by reacting alpha-olefins (C₈ -C₂₀ with sodium bisulphite and those derived from reacting paraffins with SO₂ and Cl₂ and then hydrolysing with a base to product a random sulphonate; and olefin sulphonates, which term is used to describe the material made by reacting olefins, particularly C₁₀ - C₂₀ alpha-olefins, with SO₃ and then neutralising and hydrolysing the reaction product.
Suitable nonionic surfactants which may be used are the reaction products cf compounds having a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Specific nonionic detergent compounds are alkyl (C₇ - C₂₂) phenols-ethylene oxide condensates, the condensation products of aliphatic (C₈ - C₁₈) 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.
Suitable nonionic surfactants are described in British Patent Specification GB 1460646 (The Procter & Gamble Company).
Alkylene oxide adducts of fatty materials can be used as the nonionic surfactants. The number of alkylene oxide groups per molecule has a considerable 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 molecule depends upon the nature and chain length of the fatty material.
Typical nonionic surfactants having a low HLB are the ethoxylated straight chain alcohols containing 13 to 15 carbon atoms and an average of 3 ethylene oxide groups per molecule. The HLB of such a material is about 8.3. Typical high HLB nonionics are similar materials having an average of 7 ethylene oxide groups per molecule. These have an HLB of about 11.7.
An essential component of the compositions according to the invention is an amine oxide, having at least one alkyl or alkenyl chain containing 9 to 22 carbon atoms. This is preferably of the type represented by the formula
wherein R is an alkyl or alkenyl group having 10 to 22 carbon atoms, such as from 12 to 18 carbon atoms, or the group
wherein R³ is an alkyl group containing from 8, preferably 10, up to 18 carbon atoms and X is hydrogen, methyl or a water-soluble metal, ammonium or substituted ammonium cation, each R¹ is the same or different and is selected from alkyl groups containing 1 to 4 carbon atoms and the group (-CH₂CHR²-0-)_zH where R² is hydrogen or methyl and z is an integer from 1 to 10, x is an integer from 1 to 6 and y is an integer from 0 to 6.
Suitable examples within the above formula can be obtained when R is selected from tallow or hydrogenated tallow alkyl, coconut alkyl, lauryl, palmityl, stearyl and oleyl, and R¹ is methyl or ethyl and the amine oxides derived from alpha-hydroxy fatty acids as described in European Patent Specification EP 60711 (The Procter & Gamble Company).
Specific compounds which can be used include coconut alkyl dimethyl amide oxide and N-hydrogenated tallow alkyl N,N¹,N¹ tri (2-hydroxyethyl) propylene 1,3 diamine oxide.
The compositions of the invention may include surfactant materials other than those listed above, such as from the classes of amphoteric, zwitterionic and cationic detergent active materials. Any such further surfactant materials should be present in no more than a minor amount.
The compositions of the invention may include a detergency builder which has the ability to reduce the free calcium ion concentration of the wash liquor. Another advantage of the presence of builders (when such materials are water-soluble) is the generation of an alkaline pH, it being preferred that the compositions of the invention exhibit a pH of at least 8, preferably at least 10, at a concentration of 1 g/l in distilled water at 25°C.
When the compositions of the invention 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 with other beneficial properties such as the generation of an alkaline pH and the suspension of soil removed from the fabric.
Examples of phosphorus-containing inorganic detergency builders, when present, include the water-soluble salts, especially alkali metal pyrophosphates, orthophosphates, polyphosphates and phosphonates. Specific examples of inorganic phosphate builders include sodium and potassium tripolyphosphates, ortho phosphates and hexametaphosphates.
Examples of non-phosphorus-containing inorganic detergency builders, when present, include water-soluble alkali metal carbonates, bicarbonates, silicates and crystalline and amorphous alumino silicates. Specific 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 present, include the alkali metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates, polyacetyl carboxylates and polyhydroxsulphonates. Specific examples include sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediaminetetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, melitic acid, benzene polycarboxylic acids and citric acid.
Apart from the ingredients already mentioned, a number of optional ingredients may also be present.
Examples of other ingredients which may be present in the composition include fabric softening agents such as fatty amines, fabric softening clay materials and bleaching agents such as sodium perborate and sodium percarbonate, peracid bleach precursors, chlorine-releasing bleaching agents such as trichloroisocyanuric 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.
The detergent compositions according to the invention may be in any suitable form especially powders but also bars, liquids, and pastes and may be prepared by a number of different methods according 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 salt 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 salt. The slurry is spray-dried to form base powder granules with which any solid heat-sensitive ingredients may be mixed, such ingredients including bleaches and enzymes. The specified nonionic surfacants can be liquified by melting or solvent dissolution and sprayed onto the base powder granules, rather than including them in the slurry for spray-drying. As an alternative, the nonionic surfactants, or part thereof, and/or the amine oxide may be incorporated on a suitable porous carrier material which is dry-mixed with the spray dried powder. Suitable carrier materials include water-soluble inorganic salts. The invention will now be described in more detail in the following non-limiting examples.

EXAMPLES 1A to 1E

Wash liquors were prepared in water having a hardness of 25°FH (equivalent to a free calcium ion concentration of 2.5 x 10⁻³ molar). The wash liquor contained the equivalent of 6 g/l of a composition containing (by weight).

DOB - 113 (Anionic detergent active)	9%
Specified nonionic surfactant/amineoxide	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 equivalent in ionic strength to 5% sodium perborate monohydrate which would be present in practice. The bleach is left out of these experiments in order to avoid confusion between detergency and bleaching effect in the interpretation of the results.
The wash liquors were used to wash a fabric load at a liquor to cloth ratio of 50:1. The load consisted of a number of polyester monitors to which had previously been applied an amount of C¹⁴ 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.
The wash time was 20 minutes with an agitation at 70 rpm. Washes were isothermal at temperatures as specified below.
In addition to the anionic surfactant listed above the compositions contained variously:
E₇: C_13/15 alcohol ethoxylated with approximately 7 moles of ethylene oxide per molecule, having a HLB of approximately 11.7.
E₃: C_13/15 alcohol ethoxylated with approximately 3 moles of ethylene oxide per molecule, having a HLB of approximately 8.3.
CAO: Coconut dimethyl amine oxide.
Details of the compositions tested and the results obtained were as follows:

EXAMPLE NO. E7(%) E3(%) CAO(%) Detergency

1A 1 3 0 45.1

1B 1 2 1 49.7

1C 1 1 2 54.2

1D 1 0 3 52.4

1E 0 1 3 51.2
These results show that despite the total amount of E7, E3 and CAO remaining the same (4%), the best detergency results are obtained, in Example 1C, when all three components are present. Example 1B, with all three components is superior to the Example 1A with only E7 and E3.

EXAMPLES 2A AND 2B

In a separate series of experiments the procedure of Example 1 was repeated to compare a composition which was the same as Example 1C, and a composition in which the nonionic surfactants E3 and E7 are replaced with E5, a C_13/15 alcohol ethoxylated with approximately 5 moles of ethylene oxide per molecule, having an HLB of approximately 10.0.
Results were:

EXAMPLE NO. E7(%) E5(%) E3(%) CAO(%) Detergency

2A 1 0 1 2 48.6

2B 0 2 0 2 46.3

Claims

1. A detergent composition which comprises a detergent active system comprising:

i) an anionic detergent active material;

ii) a nonionic detergent active system which is a mixture of a nonionic detergent active material with an HLB above 10.5 and a nonionic detergent active material with an HLB below 10.5; and

iii) an amine oxide having at least one alkyl or alkenyl chain containing from 9 to 22 carbon atoms.

2. A composition according to claim 1 wherein the alkyl or alkenyl chain of the amine oxide contains from 10 to 22 carbon atoms.

3. A composition according to claim 2 wherein the amine oxide is of the type represented by the formula

wherein R is an alkyl or alkenyl group having 10 to 22 carbon atoms, such as from 12 to 18 carbon atoms, or the group

wherein R³ is an alkyl group containing from 8, preferably 10, up to 18 carbon atoms and X is hydrogen, methyl or a water-soluble metal, ammonium or substituted ammonium cation, each R¹ is the same or different and is selected from alkyl groups containing 1 to 4 carbon atoms and the group (-CH₂CHR²-O-)_zH where R² is hydrogen or methyl and z is an integer from 1 to 10, x is an integer from 1 to 6 and y is an integer from 0 to 6.

4. A composition according to claim 3 wherein R is alkyl of 12 to 18 carbon atoms and y is 0.

5. A composition according to any one of the preceding claims wherein the amount of anionic detergent active material is from 4.5% to 18% by weight of the composition.

6. A composition according to any one of the preceding claims wherein the amount of the higher HLB nonionic material is from 0.5% to 4% by weight of the composition, and the level of the lower HLB nonionic material is from 1.5% to 6% by weight of the composition.

7. A composition according to any one of the preceding claims wherein the amount of amine oxide is from 1% to 4% of the composition.

8. A composition according to any one of the preceding claims wherein the total amount of the detergent active materials of the said detergent active system is from 7.5 to 30 % by weight of the composition.

9. A composition according to any one of the preceding claims which is in granular form and incorporates detergency builder.