CN1208364A - Stable Emulsions Containing Hydrophobic Liquid Components - Google Patents

Abstract

Aqueous emulsions are disclosed comprising: a hydrophobic liquid component or a mixture thereof, a hydrophobic surfactant and a hydrophilic amine oxide surfactant. The emulsions are disclosed to be useful in providing stable emulsions of cleaning agents such as bleach activators, bleaches, perfumes, solvents, enzymes, chelating agents and polymers.

Description

Stable Emulsions Containing Hydrophobic Liquid Components

Technical field

The present invention relates to aqueous emulsions containing hydrophobic liquid components.

Background technique

Cleaning compositions containing hydrophobic components such as bleaching compositions containing bleach activators have been extensively described in the prior art.

More particularly, if bleaching compositions contain hydrophobic components such as bleach activators, it is known to formulate them as emulsions of nonionic surfactants, see for example EP-A-598170. In said compositions, the bleach activator reacts with hydrogen peroxide to form a peracid which is the bleaching species.

However, a disadvantage associated with liquid compositions containing hydrophobic components, such as bleaching compositions containing bleach activators, is that they may decompose, ie undergo phase separation on prolonged storage. In practice, hydrophobic liquid components like bleach activators or insoluble or sparingly water-soluble organic peracids are used for the composition since the composition will separate into two distinct phases visible to the naked eye of the consumer. Aqueous compositions are problematic.

It is therefore an object of the present invention to provide compositions comprising hydrophobic liquid components, in particular bleaching compositions comprising hydrophobic liquid components, which have improved physical stability.

The present invention satisfies the above object like this: a kind of pH is not more than 7, contains the aqueous emulsion of hydrophobic liquid component, and this hydrophobic liquid component is emulsified in the mixture of hydrophilic amine oxide surfactant and hydrophobic surfactant in the emulsion. In fact, it has been found that: compared to the same emulsion without said hydrophilic amine oxide surfactant, or with other hydrophilic surfactants like hydrophilic nonionic surfactants instead of said hydrophilic amine oxide surface The presence of said hydrophilic amine oxide surfactant brings enhanced physical properties to emulsions containing hydrophobic liquid components such as bleach activators and/or hydrophobic sources of active oxygen and hydrophobic surfactants compared to the same emulsion of activators. stability.

An advantage of the present invention is that it allows great flexibility in formulation. Indeed, the present invention allows the incorporation of any type of hydrophobic liquid component such as a hydrophobic source of active oxygen (eg di(perododecanoic acid)) and/or a bleach activator into an aqueous composition by emulsification. Although the present invention finds preferred application in the formulation of bleaching compositions containing a bleach activator and/or a hydrophobic source of active oxygen, the present invention is also applicable to the formulation of aqueous compositions containing any hydrophobic liquid component such as a perfume.

Another advantage of the present invention is that due to the presence of hydrophilic amine oxide surfactants and hydrophobic surfactants like nonionic surfactants, it provides particularly good performance in removing different types of soils, including those found in laundry applications. Bleaches stains, greasy stains, enzymatic stains and bacterial soils in household cleaning applications.

Another advantage of the present invention is that the bleaching emulsions herein are also chemically stable.

EP-A-598170 discloses aqueous cleaning and bleaching compositions (pH 0.5-6) containing hydrogen peroxide and a hydrophobic liquid component using 2 nonionic surfactants with different HLB The mixture is emulsified. EP-A-598170 also mentions that said compositions are preferably free of other types of surfactants. However, no amine oxide surfactants are disclosed.

Copending European Patent Application 94870184.2 discloses a thickened acidic composition comprising an active oxygen source, quaternary ammonium and C6-C10 amine oxide. The patent application mentions that all other types of surfactants can also be added. However, no emulsions are disclosed.

WO95/20028 discloses a grease emulsifying dishwashing composition comprising a C10-C22 amine oxide surfactant and a detergent surfactant selected from anionic, nonionic, amphoteric and zwitterionic surfactants. Chlorine and oxygen bleaches are mentioned as optional components without further specification. Emulsions are not explicitly disclosed.

EP-A-92932 discloses compositions suitable for bleaching or disinfecting comprising hydrogen peroxide and specific bleach activators, said compositions being in the form of emulsions. Emulsifiers may be fatty acid esters or fatty ethers of polyhydroxyl-substituted compounds or polyethoxylates or amines. However, no amine oxide surfactants are disclosed.

US4541944 discloses emulsions containing hydrogen peroxide, a specific bleach activator and an emulsifier having substantially the same HLB as the activator. Such emulsifiers include ethoxylated nonionic surfactants. Other surfactants include nonionic, cationic, anionic and amphoteric surfactants. However, no amine oxide surfactants are disclosed.

EP-A-610010 discloses aqueous bleaching compositions comprising a water-insoluble peroxyacid (eg iminoperoxycarboxylic acid), a water-immiscible solvent comprising a solvent/water emulsion dispersed phase . Said compositions may also contain surfactants like anionic surfactants and/or ethoxylated nonionic surfactants. However, no amine oxide surfactants are disclosed.

GB 1092149 discloses the alkaline stabilization of nonionic surfactants such as ethoxylated nonionic surfactants and detergent surfactants selected from sultaine detergents, phosphine oxide detergents and amine oxide detergents oil-in-water emulsion (pH11.7-13). Said compositions may contain other ingredients like fungicides.

Invention Summary

The present invention is an aqueous emulsion containing hydrophobic liquid components and an emulsifying system with a pH not greater than 7, and the emulsifying system contains a hydrophilic amine oxide surfactant and a hydrophobic surfactant.

The invention also includes methods of making said emulsions.

                    Invention Details

The emulsions according to the invention are aqueous. Accordingly, the emulsions of the present invention contain 10-95%, preferably 30-90%, more preferably 50-70% water by weight of the total emulsion. Preferably deionized water is used.

The emulsions of the present invention are formulated at a pH of no greater than 7. Formulating the emulsions of the present invention in this acidic range contributes to the stability of the emulsions. In a preferred embodiment, the emulsion is formulated at a pH below 7, preferably 0-5, more preferably 0-4. The pH of the emulsion can be adjusted by all methods available to a person skilled in the art.

The emulsions of the present invention contain as an essential component a hydrophobic liquid component or a mixture thereof. The term "hydrophobic liquid component" as used herein refers to liquid components and solid materials which are dissolved in the hydrophobic liquid phase prior to incorporation into the emulsion of the present invention. "Hydrophobic" refers herein to any substance that is not sufficiently and stably miscible in water. The HLB of the hydrophobic component herein is generally below 11, preferably below 10.

Suitable hydrophobic liquid components for use herein include: bleach activators, hydrophobic sources of active oxygen, perfumes, hydrophobic solvents, enzymes, hydrophobic radical scavengers, hydrophobic chelating agents, hydrophobic brighteners, polymers and mixtures thereof . As used herein, the term "hydrophobic liquid component" means a single component or a mixture thereof.

Preferred hydrophobic liquid components for use in the emulsions of the present invention include hydrophobic sources of active oxygen or mixtures thereof.

The source of active oxygen according to the invention acts as an oxidizing agent which increases the ability of the emulsion to remove normal colored and organic stains, destroy odor molecules and kill microorganisms.

Suitable hydrophobic sources of active oxygen for use herein include: hydrophobic dialkyl peroxides, hydrophobic diacyl peroxides, hydrophobic preformed percarboxylic acids, and hydrophobic organic and inorganic peroxides. Suitable hydrophobic organic peroxides include: hydrophobic diacyl and dialkyl peroxides such as dibenzoyl peroxide, dilauroyl peroxide, dicumyl peroxide and all peroxides with a carbon number greater than 7, or a mixture thereof. Suitable hydrophobic preformed peroxyacids for use in the emulsions of the present invention include: diperoxydodecanoic acid (DPDA), magnesium perphthalate, perlauric acid, diperoxyazelaic acid, and carbon number greater than 7 All peracids, or mixtures thereof.

Other preferred hydrophobic liquid ingredients for use in the emulsions of the present invention are bleach activators. "Bleach activator" means herein any compound which reacts with hydrogen peroxide to form a peracid. As far as bleach activators are concerned, such hydrophobic bleach activators generally belong to the class of esters, amides, imides or anhydrides. Examples of suitable compounds of this type are disclosed in British Patents GB1586769 and GB2143231 and their formulation into pellets is described in European Patent Application EP-A-62523. Suitable examples of such compounds for use herein are: tetraacetylethylenediamine (TAED), sodium 3,5,5-trimethylhexanoyloxybenzenesulfonate, diperoxide as described, for example, in US4818425 Oxydodecanoic acid and peroxyadipate nonylamide and n-nonanoyloxybenzenesulfonate (NOBS) as described for example in US4259201. Also suitable are N-acyl caprolactams selected from the group consisting of: substituted or unsubstituted benzoyl caprolactam, octanoyl caprolactam, nonanoyl caprolactam, caproyl caprolactam, decanoyl caprolactam, undecylenoyl caprolactam, formyl caprolactam, Acetyl caprolactam, propionyl caprolactam, butyryl caprolactam, valeryl caprolactam or mixtures thereof. A family of bleach activators of particular interest is disclosed in EP624154, a particularly preferred family of which is acetyl triethyl citrate (ATC). An advantage of acetyl triethyl citrate is that it is environmentally friendly due to its eventual degradation to citric acid and alcohol. Furthermore, acetyl triethyl citrate has good hydrolytic stability in products on storage and is an effective bleach activator. Finally, it also provides good buildability to the composition. As used herein, unless otherwise stated, the term "bleach activator" includes mixtures of bleach activators.

The emulsions according to the invention contain 0.1-40%, preferably 0.1-20%, more preferably 0.1-15% of said liquid hydrophobic component or mixtures thereof, by weight of the total emulsion.

In the emulsion according to the present invention, the hydrophobic liquid component is emulsified in an emulsification system containing a hydrophilic amine oxide surfactant and a hydrophobic surfactant. In the present invention, the two different surfactants, namely the hydrophilic amine oxide surfactant and the hydrophobic surfactant have different HLB (hydrophilic-lipophilic balance) values, and the two The difference in HLB values of the surfactants is preferably at least 1, more preferably at least 3.

Accordingly, the emulsions according to the invention contain hydrophobic surfactants or mixtures thereof as an essential component. "Hydrophobic surfactant" refers herein to a surfactant having an HLB of less than 11, preferably less than 10, more preferably less than 9. Particularly preferred for use herein are hydrophobic nonionic surfactants. In fact, the hydrophobic nonionic surfactants used herein have excellent grease cutting properties, ie they have a solvent action that helps remove hydrophobic soils.

Thus, the emulsions according to the invention contain 0.1-30%, preferably 1-15%, more preferably 1-10% of said hydrophobic surfactants or mixtures thereof, by weight of the total emulsion.

Suitable hydrophobic nonionic surfactants for use herein include alkoxylated fatty alcohols, preferably fatty alcohol ethoxylates and/or propoxylates. In fact, various such alkoxylated fatty alcohols are commercially available with very different HLB (Hydrophile-Lipophile Balance) values. The HLB value of such alkoxylated nonionic surfactants depends essentially on the chain length of the fatty alcohol, the nature of the alkoxylation and the degree of alkoxylation. Hydrophobic nonionic surfactants suitable for use herein tend to have low degrees of alkoxylation and long chain fatty alcohols. Surfactant catalogs are available which list many surfactants, including nonionic surfactants, and their respective HLB values.

A suitable chemistry for preparing the nonionic surfactants used herein involves condensing the corresponding alcohol with an alkylene oxide in the desired ratio. Such methods are known to those skilled in the art and have been extensively described in the prior art. As an alternative, various alkoxylated alcohols suitable for use herein are commercially available from various suppliers.

Preferred hydrophobic nonionic surfactants for use in the emulsions according to the invention are surfactants with an HLB below 11 and according to the formula RO—(C ₂ H ₄ O) _n (C ₃ H ₆ O) _m H, wherein R is a C ₆ -C ₂₂ alkyl chain or a C ₆ -C ₂₈ alkyl benzene chain, and wherein n+m is 0.5-6, n is 0-6, m is 0-6, preferably n+m is 0.5- 5, n and m are 0-5. Preferred R for use herein is a _C8 - _C22 alkyl chain. Accordingly, suitable hydrophobic nonionic surfactants for use herein are Dobanol ^R 91-2.5 (HLB=8.1; R is a mixture of _C9 and _C11 alkyl chains, n is 2.5 and m is 0), or Lutensol ^R TO3 (HLB=8; R is a mixture of C ₁₃ and C ₁₅ alkyl chains, n is 3 and m is 0), or Tergitol ^R 25L3 (HLB=7.7; R is in the range of C ₁₂ to C ₁₅ alkyl chain lengths , n is 3 and m is 0), or Dobanol ^R 23-3 (HLB=8.1; R is a mixture of C ₁₂ and C ₁₃ alkyl chains, n is 3 and m is 0), or Dobanol ^R 23-2 ( HLB=6.2; R is a mixture of _C12 and _C13 alkyl chains, n is 2 and m is 0), or a mixture thereof. Preferred herein are Dobanol ^R 23-3, Dobanol ^R 23-2, Lutensol ^R TO3, or mixtures thereof. These Dobanol ^R surfactants are commercially available from SHELL. These Lutensol ^R surfactants are commercially available from BASF and these Tergitol ^R surfactants are commercially available from UNION CARBIDE.

Other suitable hydrophobic nonionic surfactants for use herein are non-alkoxylated surfactants. An example is Dobanol ^R 23 (HLB<3).

The emulsions according to the invention contain hydrophilic amine oxides or mixtures thereof as a further essential component. Suitable hydrophilic amine oxide surfactants for use in accordance with the present invention are amine oxide surfactants having the formula R ₁ R ₂ R ₃ NO, wherein R ₁ is C6-C24 alkyl, preferably C6-C18 alkyl, more preferably C6-C12 alkyl is preferred, and wherein _R2 and _R3 are each independently substituted or unsubstituted, linear or branched chain alkyl, which has 1-4 carbon atoms, preferably 1-3 carbon atoms, More preferred is methyl. R ₁ can be a saturated or unsaturated linear or branched chain alkyl group. Suitable amine oxide surfactants for use herein are preferably compatible with any source of active oxygen. Preferred amine oxide surfactants for use herein are, for example, the natural mixed C8/C10 amine oxides available from Hoechst or the C12 amine oxides available from Hoechst.

Emulsions according to the invention contain from 0.1 to 40%, preferably from 0.5 to 30%, more preferably from 1 to 10%, by weight of the total emulsion, of a hydrophilic amine oxide surfactant or mixtures thereof.

The emulsions according to the invention may also contain other surfactants like anionic surfactants, other nonionic surfactants, zwitterionic surfactants and/or amphoteric surfactants. However, the additional surfactant should not significantly alter the weight average HLB value of the overall emulsion. It is also possible to choose different surfactant levels in order to formulate emulsions with different viscosities. Thus, by appropriately selecting the content of the various surfactants, the viscosity of the emulsion can be increased and thus can be particularly suitable for use on inclined surfaces such as bathtubs, sinks or toilet bowls.

In a preferred embodiment of the emulsion of the present invention, the emulsification system satisfies the following formula:

And A% (weight) + B% (weight) = 100%; where HLB(X) represents the HLB of the hydrophobic component to be emulsified, if there are several hydrophobic components, then X represents all of them (the weight average is based on % of each component in this formula, HLB(A) represents the HLB of the hydrophilic amine oxide surfactant or mixture thereof, and HLB(B) represents the HLB of the hydrophobic surfactant or mixture thereof.

The emulsions of the present invention are physically stable. "Physically stable" means herein that the emulsion has not undergone phase separation after storage at 50°C for 2 weeks. Physical stability can also be determined by spectrometry. In this test method, the emulsion is subjected to a temperature gradient. Starting from room temperature, the temperature of the emulsion was increased by 0.1 °C per minute up to the point when phase separation occurred. This phase separation temperature is called cloud point temperature CPT. This temperature can be detected spectroscopically due to the abrupt change in transmittance that accompanies the phase separation of the emulsion.

The emulsions of the present invention contain, as an optional but highly preferred ingredient, a hydrophilic source of active oxygen or mixtures thereof. The presence of said hydrophilic source of active oxygen, especially hydrogen peroxide, is highly desirable when said hydrophobic liquid component is a bleach activator. Suitable hydrophilic sources of active oxygen include hydrogen peroxide or a water-soluble source thereof. A source of hydrogen peroxide as used herein means any compound that generates hydrogen peroxide when said compound is contacted with water. Suitable inorganic sources of water-soluble hydrogen peroxide for use herein include: persulfates, persulfuric acids, percarbonates, metal hydrophilic peroxides, perborates and persilicates.

Suitable persulfates or mixtures thereof for use herein as sources of active oxygen include monopersulfate triple salts. An example of a commercially available monopersulfate salt is potassium monopersulfate sold under the trade name Curox ^(R) by Peroxide Chemie GMBH. Other persulfates such as dipersulfates commercially available from Peroxide Chemie GMBH can be used in the emulsions according to the invention.

Additionally, other types of hydrophilic peroxides may also be used as an alternative to or in combination with hydrogen peroxide and sources thereof.

Examples of hydrophilic peroxides include: hydrophilic dialkyl peroxides, hydrophilic diacyl peroxides, hydrophilic preformed percarboxylic acids, and hydrophilic organic and inorganic peroxides. Suitable hydrophilic organic peroxides include: all peroxides having 7 or less carbon atoms, or mixtures thereof. Suitable hydrophilic pre-formed peroxyacids for use in the emulsions of the present invention include diperpimelic acid, perbenzoic acid and all peracids having a carbon number below 7, or mixtures thereof.

The emulsions according to the invention contain up to 30%, preferably 0.1-20%, more preferably 0.1-15%, of said hydrophilic source of active oxygen or mixtures thereof, by weight of the total emulsion.

The bleaching emulsions according to the invention are also chemically stable. "Chemical stable" means herein that an emulsion containing an active oxygen source such as persulfate does not lose more than 20% of the persulfate within 1 month at 25°C. The concentration of persulfate can be determined by titration with potassium permanganate after reduction with a solution containing ferrous ammonium sulfate. Such stability testing methods are known in the art and are reported, for example, in the technical information sheets for Curox ^(R) commercially available from Interox. In addition, used in the peracid literature (F.Di Furia et al., Gas-liquid Chromatography Method for Determination of Peracids), Analyst, volume 113, May 1988, pages 793-795 ) can also determine the concentration of persulfate.

Emulsions according to the present invention may also contain optional ingredients including dyes, hydrophilic brighteners, builders, pigments, soil release agents, dye transfer inhibiting agents, solvents, buffers and the like.

The emulsions according to the invention may also contain chelating agents. Suitable chelating agents may be any known to those skilled in the art, for example selected from phosphonate chelating agents, aminocarboxylate chelating agents or other carboxylate chelating agents, or polyfunctionally substituted aromatic chelating agents or Chelating agent for its mixture. These chelating agents also contribute to the stability of the peroxygen bleach-containing emulsions herein.

Such phosphonate chelating agents may include: etidronic acid (1-hydroxyethylidene-diphosphonic acid or HEDP) as well as amino phosphonate compounds including aminoalkylene poly(alkylene phosphonates), alkali metal Ethane 1-hydroxydiphosphonate, nitrilotrimethylenephosphonate, ethylenediaminetetramethylenephosphonate and diethylenetriaminepentamethylenephosphonate. These phosphonate compounds may be present either in their acid form or as salts of different cations on some or all of their acid functions. A preferred phosphonate chelating agent for use herein is diethylene triamine pentamethylene phosphonate. Such phosphonate chelating agents are commercially available from Monsanto under the trade name DEQUEST ^(R) .

Multifunctionally substituted aromatic chelating agents can also be used in the compositions herein. See US3812044, Connor et al., issued May 21,1974. Preferred compounds of this type in acid form are dihydroxydisulfobenzenes such as 1,2-dihydroxy-3,5-disulfobenzene.

A preferred biodegradable chelating agent for use herein is ethylenediamine N,N'-disuccinic acid, or alkali metal, alkaline earth metal, ammonium or substituted ammonium salts thereof, or mixtures thereof. Ethylenediamine N,N'-disuccinic acid, especially the (S,S) isomer, has been extensively described in US4704233, November 3, 1987 to Hartman and Perkins. For example, ethylenediamine N,N'-disuccinic acid is commercially available from Palmer Research Laboratories under the tradename ssEDDS( ^R) .

Suitable aminocarboxylate chelating agents useful herein include: ethylenediaminetetraacetate, diethylenetriaminepentaacetate, diethylenetriaminepentaacetate (DTPA), N-hydroxy Ethylethylenediaminetriacetate, nitrilotriacetate, ethylenediaminetetrapropionate, triethylenetetraminehexaacetate, ethanol diglycine, propylenediaminetetraacetic acid (PDTA) and formazan Glycine diacetic acid (MGDA), both in their acid form or in their alkali metal, ammonium and substituted ammonium salt forms. Particularly suitable for use herein are diethylenetriaminepentaacetic acid salts (DTPA), such as propylenediaminetetraacetic acid (PDTA) and methylglycinediacetic acid (MGDA) ^commercially available from BASF under the tradename Trilon FS®. .

Other carboxylate chelating agents useful herein include malonic acid, salicylic acid, glycine, aspartic acid, glutamic acid, or mixtures thereof.

In general, emulsions according to the invention contain up to 5%, preferably 0.01-1.5%, more preferably 0.01-0.5%, of chelating agent or mixtures thereof, by weight of the total emulsion.

The emulsions according to the invention may also contain free radical scavengers. Suitable free radical scavengers for use herein include: known substituted mono- and dihydroxybenzenes and derivatives thereof, alkyl and aryl carboxylates and mixtures thereof. Preferred such free radical scavengers for use herein include: di-tert-butylhydroxytoluene, hydroquinone, di-tert-butylhydroquinone, mono-tert-butylhydroquinone, tert-butylhydroxyanysole, benzoic acid, toluic acid, phthalate Phenol, tert-butylcatechol, 2-methoxyphenol, 2-ethoxyphenol, 4-allyl-catechol, 2-methoxy-4-(2-propenyl)phenol, benzyl amine, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, and n-propyl gallate. Very preferred is di-tert-butylhydroxytoluene, such as is commercially available from SHELL under the tradename IONOL CP ^(R) . These free radical scavengers also assist in the stabilization of the peroxygen bleach-containing emulsions herein.

In general, the emulsions according to the invention contain up to 5%, preferably 0.01-1.5%, more preferably 0.01-0.5%, of free-radical scavengers or mixtures thereof, by weight of the total emulsion.

The present invention also includes methods of making the emulsions described herein. The method according to the invention comprises at least 3 steps:

In the first step, a hydrophobic mixture containing at least the hydrophobic surfactant and the hydrophobic liquid component is prepared.

In the second step, a hydrophilic mixture containing at least the water and the hydrophilic amine oxide surfactant is prepared. The hydrophilic mixture preferably also contains other hydrophilic components to be formulated into the emulsion, such as hydrophilic sources of active oxygen, dyes, optical brighteners, builders, buffers and agents to adjust the pH to the desired value. Organic and/or inorganic acids. In this 2nd step, if a hydrophilic source of active oxygen is present, it is preferably added last, after the buffer has been added.

Naturally, the first step and the second step can be performed in any order, that is, it is also suitable to perform the second step first.

In step 3 of the method according to the invention, said hydrophobic mixture and said hydrophilic mixture are mixed together.

The invention is further illustrated by the following examples.

Example

Emulsions were prepared containing the components in the proportions (% by weight) listed in the table below.

Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Dobanol ^R 91-2.5 4.9 4.7 4.9 4.7 4.7C12 amine oxide 2.1 2.3 2.1 2.3 ---C8/C10 amine oxide--- --- --- --- 2.3 Acetyl triethyl citrate 3.5 --- --- --- --- Hydrogen Peroxide 6.0 --- --- --- --- Citric Acid 4.0 4.0 --- --- --- Potassium Monopersulfate --- --- - 6 6 4 sulfuric acid --- --- 6 6 --- methanesulfonic acid --- --- --- --- 5 dibenzoyl peroxide --- 3 --- -- -- - Deionized water ---------- balance to 100% -------

Compositions I-V are obtained which are stable emulsions both from the chemical and physical point of view. Additionally, these emulsions provide excellent cleaning performance on hard surfaces and in laundry applications.

Compositions I-V were prepared individually by making 2 mixtures. A hydrophilic mixture was prepared containing water, amine oxide surfactant, citric acid (if present), methanesulfonic acid (if present), and sulfuric acid (if present). As a final step, hydrogen peroxide (if present) or monopersulfate (if present) is added to the hydrophilic mixture. Prepare a hydrophobic mixture containing Dobanol R 91-2.5 and acetyl triethyl citrate (if present) and dibenzoyl peroxide (if present).

Then, pour the hydrophobic mixture into the hydrophilic mixture while stirring.

Claims (13)

1. An aqueous emulsion having a pH not greater than 7, comprising a hydrophobic liquid component and an emulsifying system comprising a hydrophilic amine oxide surfactant and a hydrophobic surfactant. 2. The emulsion according to claim 1, wherein said hydrophobic liquid component is: a bleach activator, a hydrophobic source of active oxygen, a perfume, a hydrophobic solvent, an enzyme, a hydrophobic free radical scavenger, a hydrophobic chelating agent, a polymer, or a mixture thereof. 3. An emulsion according to any preceding claim, wherein said hydrophobic liquid component is: preferably selected from the group consisting of hydrophobic dialkyl peroxides, hydrophobic diacyl peroxides, hydrophobic preformed percarboxylic acids, hydrophobic organic Hydrophobic sources of active oxygen with inorganic peroxides or mixtures thereof, and/or preferably selected from tetraacetylethylenediamine, sodium 3,5,5-trimethylhexanoyloxybenzenesulfonate, diperoxydeca Bleach activators of dialkanoic acid, nonylamide of peroxyadipate, n-nonanoyloxybenzenesulfonate, N-acyl caprolactam, acetyl triethyl citrate or mixtures thereof. 4. An emulsion according to any preceding claim, wherein said emulsion contains 0.1-40%, preferably 0.1-20%, more preferably 0.1-15%, by weight of the total emulsion, of said liquid hydrophobic component or a mixture thereof. 5. An emulsion according to any one of the preceding claims, wherein said emulsion further contains a compound selected from the group consisting of hydrogen peroxide, persulfate, persulfuric acid, percarbonate, metal hydrophilic peroxide, perborate, persilicate The hydrophilic source of active oxygen, or a mixture thereof, and is preferably hydrogen peroxide or monopersulfate. 6. The emulsion according to claim 7, wherein said emulsion contains 0.1-30%, preferably 0.1-20%, more preferably 0.1-15% of said hydrophobic source of active oxygen or a mixture thereof by weight of the total emulsion. 7. An emulsion according to any preceding claim, wherein said hydrophobic surfactant is a surfactant having an HLB of up to 11, preferably less than 10, more preferably less than 9. 8. An emulsion according to any preceding claim, wherein said hydrophobic surfactant is a nonionic surfactant. 9. An emulsion according to any preceding claim, wherein said emulsion contains 0.1-30%, preferably 1-15%, more preferably 1-10%, by weight of the total emulsion, of said hydrophobic surfactant or mixtures thereof. 10. An emulsion according to any preceding claim, wherein said hydrophilic amine oxide surfactant is an amine oxide surfactant of the formula R ₁ R ₂ R ₃ NO, wherein R ₁ is a linear or branched, saturated Or unsaturated C6-C24 alkyl, preferably C6-C18 alkyl, more preferably C6-C12 alkyl, and wherein R ₂ and R ₃ are each independently substituted or unsubstituted, straight-chain or branched-chain alkyl , which has 1-4 carbon atoms, preferably 1-3 carbon atoms, more preferably methyl. 11. An emulsion according to any preceding claim, wherein said emulsion contains 0.1-40%, preferably 0.5-30%, more preferably 1-10% of said hydrophilic amine oxide surfactant or its mixture. 12. An emulsion according to any preceding claim, which has a pH below 7, preferably 0-5, more preferably 0-4. 13. A method of preparing an emulsion according to any preceding claim, wherein: - preparing a hydrophobic mixture comprising at least said hydrophobic surfactant, said hydrophobic liquid component or a mixture thereof; - preparing a hydrophilic mixture comprising at least said water, said hydrophilic amine oxide surfactant, and, if present, said hydrophilic source of active oxygen; - mixing said hydrophobic mixture and said hydrophilic mixture together.