CA2240448A1

CA2240448A1 - Stable emulsions comprising a hydrophobic liquid ingredient

Info

Publication number: CA2240448A1
Application number: CA002240448A
Authority: CA
Inventors: Sergio Cardola; Giulia Ottavia Bianchetti
Original assignee: Individual
Current assignee: Procter and Gamble Co
Priority date: 1995-12-16
Filing date: 1996-12-09
Publication date: 1997-06-26
Also published as: EP0779357A1; AU1292997A; TR199801114T2; AR005104A1; EP0910465A1; WO1997022407A1; CN1208364A; MX9804848A; ZA9610435B; JPH11501576A; BR9612038A; EP0910465A4

Abstract

Aqueous emulsions are disclosed which comprise a hydrophobic liquid ingredient or mixtures thereof, a hydrophobic surfactant and a hydrophilic amine oxide surfactant. The emulsions disclosed are useful in the stable emulsion delivery of cleaning agents such as: bleach activators, bleaching agents, perfume, solvent, enzyme chelating agents, and polymers.

Description

CA 02240448 1998-06-1~
W O 97~2407 PCT~US96/20066 STABI.E EMULSIONS COMPRISING
A HYDROPHOBIC LIQUID lI\iGREDlENT

0 Technical field The present invention relates to aqueous emulsions comprising a hydrophobic liquid ingredient.

Backqround 20 Cleaning compositions comprising hydrophobic ingredients such as bleaching compositions comprising bleach activators have been extensively described in the art.

More particularly, it is known to formulate bleaching compositions, if they 25 comprise a hydrophobic ingredient like a bleach activator, as an emulsion of nonionic su.racL;s,lts, see for instance EP-A- ~9~3 170. In said compositions the bleach activator reacts with hydrogen peroxide to yield a peracid which is the bleaching species.

30 However a drawback associated with liquid compositions comprising hydrophobic ingredients, e.g. bleachinç~ compositions co,.".rising bleach activators, is that they may decompose, i.e., undergo a phase separation upon long storage period. Indeed, hydrophobic liquid ingredients like bleach activators or aqueous insolublc or sparingly soluble organic peroxy acids are 35 problematic to use in an aqueous composition as said composition tends to separate into two dirre~t "L layer phases which can be visualised by the consumer.

CA 02240448 1998-06-1~

WO 97/22407 PCTrUS96/20066 It is thus an object o~ the present invention to provide a composition comprising a hydrophobic liquid ingredient, especially a bleaching composition comprising a hydrophobic liquid ingredient, with improved physical stability.

The present invention meets the above object in proposing an aqueous emulsion having a pH of not more than 7, comprising a hydrophobic liquid ingredient emulsified in said emulsion by a mixture of a hydrophilic amine oxide surfactant and a hydrophobic surfactant. Indeed, it has now been 10 found that the presence of said hydrophilic amine oxide surfactant gives to an emuision comprising a hydrophobic liquid ingredient such as a bleach activator and/or a hydrophobic source of active oxygen, and a hydrophobic surfactant an increased physical stability, compared to the same emulsion without said hydrophilic amine oxide surfactant or to the same emulsion but 15 with another hydrophilic surfactant like a hydrophilic nonionic surfactant instead of said hydrophilic amine oxide surfactant.

An advantage of the present invention is that it allows for great flexibility informulating. Indeed, the ,~,resent invention allows to incorporate any kind of 20 hydrophobic liquid ingredient such as a hydrophobic source of active oxygen (e.g., diperdodecanoic acid) and/or a bleach activator, in an aqueous cornposition through emulsification. Although the present invention finds a preferred application in formulating bleaching compositions comprising bleach activators and/or hydrophobic sources of active oxygen, th~ present 26 invention is also applicable to the formulation of aqueous cornpositions which comprise any hydrophobic liquid ingredient like perfumes.

Another advantage of the present invention is that, due to the presence of hydrophilic amine oxide surfactants and hydrophobic surfactants like 30 nonionic surfactants, particularly good performance in removing ~lirr~rent types of soils including bleachable stains, greasy stains, enzymatic stains in laundry application as well as bacterial soils in household cleaning application is provided.

35 A further advantage of the present invention is that the bleaching emulsions herein are also chemically stable.

CA 02240448 1998-06-1~

EP-A-598 170 discloses aqueous cleaning and bleaching compositions (pH
0.5-6) comprising hydrogen peroxide and a hydrophobic liquid ingredient, said hydrophobic liquid ingredient being emulsified by a mixture of two nonionic surfactants having different HLB. EP-A-598 170 further mentions 5 that said compositions are preferably free of other surfactant types. No amine oxide surfactants are disclosed.

Co-pending European patent application n~ 94870184.2 discloses a thickened acidic composition comprising a source of active oxygen, a 10 quaternary ammonium and a C6-C10 amine oxide. This patent application mentions that other surractants of all types may be added. However, no emulsions are disclosed.

WO ~15/20028 discloses grease emulsifying dishwashing compositions 15 comprising a C10-C22 amine oxide Surractarlt and a detergent surfactant selected from the group of anionic, nonionic, amphoteric and zwitterionic surfactants. Chlorine and oxygen bleaches are mentioned as optional ingredients without further specifying them. No emulsion is expressly disclosed.
EP-A- 92 932 discloses a composition suitable for use in bleaching or disinfection containing hydrogen peroxide and a specific bleach activator, said composition being in the form of an emulsion. The emulsifier may be fatty acid esters or fatty ethers or amines of a polyhydroxy substituted 25 compound or a polyethoxylate. No amine oxide su, ractanLs are disclosed.

US-4 541 944 discloses emulsions comprising hydrogen peroxide, a specific bleach activator and an emulsifier, said emulsifier having an HLB being suLsLa.~Liall~y the same as that of the activator. Such emulsifiers include 30 ethoxylated nonionic SUI r~Cta~ IL~. Other surfactants include nonionic, cationic, anionic and amphotheric surfactants. No amine oxide surfactants are disclosed.

EP-A-610 010 ~Jiscloses an aqueous bleaching composition comprising a 35 water insoluble peroxy acid ~e.g. an imido peroxycarboxylic acid~, a water imr. ~iscible solvent, said solvent comprising the dispersed phase of a solvent/water emulsion. Said compositions may further comprise WO 97~2407 PCT~US96~0066 surfactants like anionic surfactants and/or ethoxylated nonionic surfactants.
No amine oxide surfactants are disclosed.
GB 1 092 149 discloses alkaline stable oil-in-water ernulsions (ptl 11.7 to 13) of nonionic su, racLants (e.g. ethoxylated nonionic surfactant) and a 5 detergent surfactant being selected from the group of sultaine detergent, phosphine oxide detergent and amine oxide detergent. Said compositions may comprise other ingredients like a germicide.

Summarv of the invention The present invention is an aqueous emulsion having a pH of no more than 7, comprising a hydrophobic liquid ingredient and an emulsifying systern 15 comprising a hydrophilic amine oxide surfactant and a hydrophobic surfactant.

The ~,resent invention also enco~.-,uasses a process for the manufacture of said emulsion.

{)etailed desc-i~,lion of the invention 25 The emulsions according to the present invention are aqueous.
Accordingly, the emulsions accordi--g to the present invention comprise from 10% to 9~% by weight of the total emulsion of water, prefer~,bly from 30% to 90%, most preferc,l,ly from 50% to 70%. Deionized water is preferal~ly used.
The emulsions of the present invention are formulated at a pH of no more than 7. Formulating the emulsions according to the present invention in this acidic pH range contributes to the stability of the emulsion. In a preferred embodiment, the emulsions are formulated at a pH below 7, pleferably of 35 frorn 0 to !~, and more preferably of from 0 to 4. The pH of the emulsion can be trimmed by all means available to the man skilled in the art.

CA 02240448 1998-06-1~

W O 97n2407 PCTAUS96nO066 The emulsions according to the present invention comprise, as an essential element, a hydrophobic liquid ingredient, or mixtures thereof. As used herein, the term "hydrophobic liquid ingredient" refers both to iiquid ingredients, and solid materials which are dissolved in a hydrophobic liquid 5 phase prior to incorporation into the emulsions of the invention. By hydrophobic, it is meant herein any material which is not substantially and stably miscible in water. Hydrophobic ingredients herein typically have an I ILB below 11, preferably below 10.

10 Suitable hydrophobic liquid ingredients to be used 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 ingredient refers to single ingredients or 15 mixtures thereof.

Preferred hydrophobic liquid ingredients to be used in the emulsions according to the present invention include a hydrophobic source of active oxygen, or mixtures thereof.
20 The source of active oxygen according to the present invention acts as an oxidising agent, it increases the ability of the emulsions to remove colored stains and organic stains in general, to destroy malodorous molecules and to kill germs.
Suitable hydrophobic sources of active oxygen to be used herein include 25 hydrophobic dialkylperoxides, hydrophobic diacylperoxide, hydrophobic prefGr...ed percarboxylic acids, as well as 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 number of carbon above 7, or 30 mixtures thereof. Suitable hydrophobic preformed peroxyacids for use in the emulsions according to the pres~, ~ L invention include diperoxydodecandioic acid (DPDA), magnesium perphthalic acid, perlauric acid, diperoxy~el~ic acid and all peracids with a number of carbon above 7, or mixtures Ll .ereof .

CA 02240448 1998-06-1~
W O 97~2407 PCTAUS96/20066 Other preferred hydrophobic liquid ingredients to be used in the emulsions according to the present invention are bleach activators. By bleach activator, it is meant herein any compound which reacts with hydrogen peroxide to form a peracid. In the case of bleach activators, such 5 hydrophobic bleach activators typically belong to the class of esters, amides, imides, or anhydrides. Examples of suitable compounds of this type are disclosed in British Patent GB 1 586 769 and GB 2 143 231 and a method for their formation into a prilled form is described in European Published Patent Application EP-A-62 523. Suitable examples of such 0 compounds to be used herein are tetracetyl ethylene diamine (TAED), sodium 3,5,E; trimethyl hexanoyloxybenzene sulphonate, diperoxy dodecanoic acid as described for instance in US 4 818 425 and nonylamide of peroxyadipic acid as described for instance in US 4 259 201 and n-nonanoyloxybenzenesulphonate (NOBS). Also suitable are N-acyl 15 caprolactam selected from the group consisting of substituted or unsubstituted benzoyl caprolactam, octanoyl caprolactam, nonanoyl caprolactam, hexanoyl caprolactam, decanoyl caprolactam, undecenoyl caprolactam, formyl caprolactam, acetyl caprolactam, propanoyl caprolactam, butanoyl caprolactam pentanoyl caprolactam or mixtures 20 thereof. A particular family of bleach activators of interest was disclosed in EP 624 154, and particularly preferred in that family is acetyl triethyl citrate(ATC). Acetyl triethyl citrate has the advantages that it is environmentally friendly as it eventually degrades into citric acid and alcohol. Furthermore, acetyl triethyl citrate has a good hydrolytical stability in the product upon 25 storage and it is an efficient bleach activator. Finally, it provides good building capacity to the con position. As used herein and unless otherwise specified, the term bJeach activator includes mixtures of bleach activators.
The emuisions according to the present invention comprise from 0.1% to 40% by weight of the totai emulsion of said liquid hydrophobic ingredient, 30 or rnixtures thereof, preferably from 0. 1% to 20%, and more prefel &LIy from 0.1% to ~5%.

In the emulsions according to the present invention, said hydrophobic liquid ingredient is emulsified ll ~erei, . by means of an emulsifying system 35 comprising a hydrophilic amine oxide surfactant and a hydrophobic su.ract~llt. In tha ~rese,-t invention said two dirrere~.L su.fs~;ldnls, i.e., the CA 02240448 1998-06-1~

W O 97/22407 PCT~US96/20066 hydrophilic amine oxide surfactant and the hydrophobic surfactant, have different H~B values (hydrophilic lipophilic balance), and the difference in value of the HLBs of said two surfactants is preferably at least 1, more preferably at least 3.

Thus, the emulsions according to the present invention comprise, as an essential element, a hydrophobic surfactant, or mixtures thereof. By "hydrophobic surfactant" it is meant herein a surfactant having an HLB
below 1 1, preferably below 10, more preferably below 9. Particularly 10 preferred to be used herein are hydrophobic nonionic surfactants. Indeed, the hydrophobic nonionic surfactants to be used herein have excellent grease cutting properties, i.e. they have a solvent effect which contributes to hydrophobic soils removal.

15 Accordingly, the emulsions according to the present invention comprise from 0. 1% to 30% by weight of the total emulsion of said hydrophobic surfactant or mixtures thereof, preferably from 1% to 15% and more preferably from 1 % to 1 0% .

20 Suitable hydrophobic nonionic surfactants for use herein include alkoxylated fatty alcohols preferably, fatty alcohol ethoxylates and/or propoxylates.
Indeed, a great variety of such alkoxylated fatty alcohols are commercially available which have very dirrerellt HLB values (hydrophilic lipophilic balance). The HLB values of such alkoxylated nonionic surfactants depend 25 essentially on the chain length of the fatty alcohol, the nature of the alkoxylation and the degree of alkoxylation. Hydrophobic nonionic su. racla..ls suitable to be used herein tend to have a low degree of alkoxylation and a long chain fatty alcohol. Surfactants catalogs are available which list a number of su.raclants including nonionics, together 30 with their respective HLB values.

Suitable chemical processes for preparing the nonionic su,racta"ts for use herein include condensation of corresponding alcohols with alkylene oxide, in the desired proportions. Such processes are well known to the man 35 skilled in the art and have been extensively described in the art. As an alternative, a great variety of alkoxylated alcohols suitable for use herein is commercially available from various suppliers.

WO 97~2407 PCT~US96/20066 Preferred hydrophobic nonionic surfactants to be used in the emulsions according to the present invention are surfactants having an HLB below 11 and being according to the formula RO-(C2H40)n(C3tl60)mH, wherein R is a C6 to C22 alkyl chain or a C6 to C2g alkyl benzene chain, and wherein n+m is from 0.5 to 6 and n is from O to 6 and m is from O to 6 and preferably n+m is from 0.5 to 5 and, n and m are from O to 5. The preferred R chains for use herein are the C8 to C22 alkyl chains.
Accordingly, suitable hydrophobic nonionic surfactants for use herein are 0 Dobanol R 91-2.5 (HLB= 8.1; R is a mixture of Cg and C1 1 alkyl chains, n is 2.5 and m is 0~, or Lutensol R T03 (HLB=8; R is a mixture of C13 and C1 5 alkyl chains, n is 3 and m is 0), or Tergitol R 25L3 ~HLB= 7.7; R is in the range of C12 to C1s alkyl chain length, n is 3 and m is 0~, or Dobanol R 23-3 (HLB--8.1; R is a mixture Of C12 and C13 alkyl chains, n is 3 and ts m is 0), or Dobanol R 23-2 (HLB= 6.2; R is a mixture of C12 and C13 alkyi chains, n is 2 and m is 0), or mixtures thereof. Preferred herein are Dobanol R 23-3, or Dobanol R 23-2, Lutensol R T03, or mixtures thereof.
These Dobanol R surfactants are commercially available from SHELL. These Lutensol R surfactants are commercially available from BASF and these 20 Tergitol R surfactants are cor,.r,~ercially avsilable from UNION CAR~IDE.

Other suitable hydrophobic nonionic sulrd~;~dllls to be used herein are non alkoxylated su.ra-,-La.)Ls. An example is Dobanol R 23 (HLB<3 ).

25 The emulsions accGr.J;"g to the present invention comprise, as a further essential ele,-,e"t, a hydrophilic amine oxide su, ra~;tarit, or mixtures thereof.
Suitable hydrophiiic amine oxide surfactants to be used according to the presenl invention are amine oxide su.rac~anls having the following formula R1R2R3NO wherein R1 is a C6 to C24 alkyl group"~referaL,ly a C6 to C18 30 alkyl group and more ~referaLly a C6 to C12, and wherein R2 and R3 are independently substituted or unsubstituted, linear or branched alkyl groups of from 1 to 4 carbon atoms, preferably of from 1 to 3 carbon atoms and more preferably are rnethyl groups. R1 may be a linear or branched alkyl group, being saturated or unsaturated. Suitable amine oxide su- racLd~ . for 35 use herein are ,ureferably compatible with any source of active oxygen.
rl efe~ amine oxide su- racld- ~ts for use herein are for instance natural CA 02240448 1998-06-1~

W O 97/22407 PCT~US96/20066 blend C8/C10 amine oxide available from Hoechst or C12 amine oxide available from Hoechst.

The emulsions according to the present invention comprise from 0.1% to 5 40% by weight of the total emulsion of a hydrophilic amine oxide surfactant, or mixtures thereof, preferably of from 0.5% to 30% and more preferably of from 1% to 10%.

The emulsions according to the present invention may further comprise 0 other SUrraCtalltS like anionic surfactants, other nonionic surfactants, zwitterionic su- r~cLa.lLs and/or amphotheric surfactants. Said additional surracLanLs should however not significantly alter the weighted average HLB
value of the overall emulsion. Also the level of the dirre~ent surfactants present may be chosen so as to formulate emulsions with different 15 viscosities. Thus by appropriately choosing the level of the dirrerent surfactants, the viscosity of the emulsion may be increased and thus may be particularly suitable to be used on inclined surfaces such as bath tubs, sinks or toilet bowls.

20 In a preferred embodiment of the emulsions of the present invention, the emulsifying system meets the equation:

weight%A weight%B
HLB(X) = x HLB(A) ~ x HLB(B) and weight %A+ weight%B =

2~ 1 00%;

where HLB (X) refers to the HLB of the hydrophobic ingredient to emulsify, if several hydrophobic ingredients are present X refers to the all of them 30 ~weiyl,led average based on % of each ingredient in the formula), HLB (A) refers to the HLB of said hydrophilic amine oxide surfactant, or mixtures thereof, and HLB (B) refers to the HLB of said hydrophobic surfactant, or mixtures thereof.

35 The emulsions of the present invention are physically stable. By "physically stable" it is meant herein that said emulsions do not undergo a phase separation after storage at 50~C for a period of two weeks. Physical CA 02240448 1998-06-1~
WO 97n2407 PCT~US96~0066 stability may also be measured by spectrophotometry. In this test method emulsions are suL~ Led to a temperature gradient. Starting from room temperature the emulsions temperature is increased by 0.1 ~C per minute up to when a phase separation occurs. The temperature of the phase separation is called Cloud Point Temperature CPT. This temperature can be detected spectrometrically due to a transmittance jump that occurs concomitantly to the emulsion phase separation.
The emulsions of the present invention comprise as an optional but highiy preferred ingredient a hydrophilic source of active oxygen, or mixtures 10 thereof. The presence of said hydrophilic source of active oxygen, in particular hydrogen peroxide, is highly desired when said hydrophobic liquid ingredient is a bleach activator. Suitable hydrophilic source of active oxygen include hydrogen peroxide or a water soluble source thereof. As used herein a hydrogen peroxide source refers to any compound which produces 15 hydrogen peroxide when said compound is in contact with water. Suitable water-soluble inorganic sources of hydrogen peroxide for use herein include persulfate, persulfuric acid, percarbonates, metal hydrophilic peroxides, perborates and persilicate salts.
Suitable persulfate salts or mixtures thereof to be used herein according to 20 the present invention, as a sourca of active oxygen includes monopersulfate triple salt. One example of monopersulfate salt commercially available is potassium monopersulfate co-,-,nerci~lise~l by Peroxide Chemie GM~H under the trade name Curox(g). Other persulfate salts such as dipersulfate salts commercially available from Peroxide Chemie GMBH can be used in the 25 emulsions according to the present invention.
In addition, other cla-sses of hydrophilic peroxides can be used as an alternative to hydrogen peroxide and sources thereof or in combination with hydrogen peroxide and sources thereof.
Examples of hydrophilic peroxides include hydrophilic dialkylperoxides, 30 hydrophilic diacylperoxide, hyJro~l)il;c preformed percarboxylic acids and hydrophilic organic and inorganic peroxides. Suitable hydrophilic organic peroxides include all peroxides with a number of carbon atoms below or equal to 7, or mixtures thereof. Suitable hydrophilic preformed peroxyacids for use in the emulsions according to the ~rese, ~t invention include CA 02240448 1998-06-1~
W O 97/22407 PCTAUS96/20~66 diperpimelic acid, perbenzoic acid and all peracids with a number of carbons below 7, or mixtures thereof.
The emulsions according to the present invention comprise up to 30% by weight of the total emulsion of said hydrophilic source of active oxygen, or mixtures thereof, preferably from 0.1% to 20%, and more preferably from 0.1% to 15%.

The bleaching emulsions according to the present invention are also chemically stable. By "chemically stable" it is meant herein that an 0 emulsion comprising a source of active oxygen such as for instance a persulfate salt, does not undergo more than 20 % persulfate loss, in one month at 25~C. Persulfate concentration can be measured by titration with potassium permanganate after reduction with a solution containing ammonium ferrous sulphate. Said stability test method is well known in the art and is reported, for example, on the technical information sheet of Curox OE commercially available from Interox. Alternatively persulfate collce~llrdLion can also be measured using a chromatography method described in the lit~rature for peracids (F. Di Furia et al., Gas-liquid Chromatography Method for Determination of Peracids, Analyst, Vol 113, May 1988, p 793-795).

The emulsions according to the present invention may also comprise optional ingredients including dyes, hydrophilic brighte, ~ers, builders, pi91l ,e"ts, soil release agents, dye transfer inhibitors, solvents, buffering 25 agents and the like.

The emulsions acco. .li. ~9 to the present invention may further comprise a chelating agent. Suitable chelating aye,.L~ may be any of those known to those skilled in the art such as the ones selected from the group comprising 30 phosphonate chelating agents, amino carboxylate chelating agents or other carboxylate chelating agents, or polyfunctionally-substituted aromatic - chelating agents or mixtures thereof. These chelating agents further contribute to the stability of the peroxygen bleach-containing emulsions herein.

CA 02240448 l998-06-l5 W097/22407 PCTrUS96~0066 Such phosphonate chelating agents may include etidronic acid ~1-hydroxyethylidene-bisphosphonic acid or HEDP) as well as amino phosphonate compounds, including amino alkylene poly (alkylene phosphonate), alkali metal ethane 1-hydroxy diphosphonates, nitrilo trimethylene phosphonates, ethylene diamine tetra methylene phosphonates, and diethylene triamine penta methylene phosphona~es. The phosphonate cornpounds may be present either in their acid form or as salts of different cations on some or all of their acid functionalities. Preferred phosphonate chelating agents to be used herein are diethylene triamine 0 penta methylene phosphonates. Such phosphonate chelants are commercially available from Monsan~o under the trade name DEQUEST(~3)-Polyfunctionally-substituted aromatic chelating agents may also be useful in the compositions herein. See U.S. patent 3,812,044, issued May 21, 15 1974, to Connor et al. P~efer.ed compounds of this type in acid form are dihydroxydisulfobenzenes such as 1,2-dihydroxy-3,~;-disulfobenzene.

A preferred biodey-ddable chelating agent for use herein is ethylene diamine N,N'- disuccinic acid, or alkali metal, or alkaline earth, amrnonium or 20 substitutes ammonium salts thereof or mixtures thereof. Ethylenediamine N,N'- disuccinic acids, especially the (S,S) isomer have been extensively described in US patent 4, 704, 233, November 3, 1987 to Hartman and Perkins. Ethylenediamine N,N'- disuccinic acid is, for instance, commercially available under the tradename ssEDDS(~' from Palmer Research Laboratories.
25 Suitable amino carboxyiate chelating agénts useful herein include ethylene diamine tetra ace~al~s, diethylene triamine pentaacetates, diethylene triamine pentoaceldLe (DTPA), N-hydroxyethylethylenediamine triacetates, nitrilotri-aceldles, ethylenediamine tetraproprionates, triethyleneteL. aaminehexa-act:LaLes, ethanoldiglycines, propylene di8ll ,in 30 teLracelic acid (PDTA) and methyl glycine di-acetic acid (MGDA), both in their acid form, or in their alkali metal, ammonium, and substituted ammonium salt forms. Particularly suitable to be used herein are diethylene triamine penta acetic acid ~DTPA), propylene diamine tetracetic acid (PDTA) which is, for instance, commercially available from BASF under the trade 35 narne Trilon FS(B) and methyl glycine di-acetic acid ~MGDA).

CA 02240448 l998-06-l~

W O 97/22407 PCTAUS96~0066 Further carboxylate chelating agents to be used herein include malonic acid, salicylic acid, glycine, aspartic acid, glutamic acid, or mixtures thereof.

Typically, the emulsions according to the present invention comprise up to 5 5% by weight of the total emulsion of a chelating agent, or mixtures thereof, preferably from 0.01% to 1.5% by weight and more preferably from 0.01%
to 0.5%.

The emulsions according to the present invention may further comprise a - 10 radical scavenger. Suitable radical scavengers for use herein include the well-known substituted mono and di hydroxy benzenes and derivatives thereof, alkyl- and aryl carboxylates and mixtures thereof. Preferred radical scavengers for use herein include di-tert-butyl hydroxy toluene, hydroquinone, di-tert-butyl hydroquinone, mono-tert-butyl hydroquinone, tert-15 butyl-hydroxy anysole, benzoic acid, toluic acid, catechol, t-butyl catechol, 2-methoxy-phenol, 2-ethoxy-phenol, 4-allyl-catechol, 2-methoxy-4-(2-propenyl~phenol, benzylamine, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl) butane, as well as n-propyl-gallate. Highly preferred for use herein is di-tert-butyl hydroxy toluene, which is for example commercially available from 20 SHELL under the trade name IONOL CP~. These radical scavengers further contribute to the stability of the peroxygen bleach-containing emulsions herein.

25 Typically, the emulsions according to the present invention comprise up to 5% by weight of the total emulsion of a radical scavenger, or mixtures thereof, preferably from 0.01% to 1.5% by weight and more preferably from 0.01% to 0.5%.

The present invention further encGI~passes a process for the manufacture of the emulsions described herein. The process according to the present invention comprises at least three steps:
J

In the first step, a hydrophobic mixture is prepared which comprises at least said hydrophobic surfactant and said hydrophobic liquid ingredient.

CA 02240448 l998-06-l~
W O 97/22407 PCT~US96/20066 In the second step, a hydrophilic mixture is prepared which comprises at least said water, and said hydrophilic amine oxide surfactant. Said hydrophilic mixture preferably further comprises other hydrophilic 5 ingredients which are to be formulated in the emulsion such as hydrophilic source of active oxygen, dyes, optical brighteners, builders, buffering agents, and organic and/or inorganic acids to adJust the pH to the desired value. In this second step the hydrophilic source of active oxygen, if present, is preferably added last, after said buffering agent has been added.

Naturally, said first and said second steps can be performed in any order, i.e. second step first is also suitable.

5 In the third step of the process according to the present invention, said hydrophobic mixture and said hydrophilic mixture are mixed together.

The present invention is further illustrated by the following examples.
Examples Emulsions are made which cornprise the listed ingredients in the listed proportions (weight %).

ll lll IV V
Dobanol R 91-2.5 4.9 4.7 4.9 4-7 4-7 C12 amine oxide 2.1 2.3 2.1 2.3 ---C8/C10 amine oxida --- --- --- --- 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 up to 100~

CA 02240448 l998-06-l~

W O 97/22407 PCT~US96nO066 Compositions I to V were obtained which were stable emulsions, both from a chemical and a physical standpoint. Also, these emulsions deliver 5 excellent cleaning performance on hard-surfaces and in laundry application.

Compositions I to V are each made by preparing two mixtures. A
hydrophilic mixture is prepared which comprises the water, the amine oxide surfactant, citric acid if present, methanesulfonic acid if present, and 10 sulfuric acid if present. Hydrogen peroxide, if present or monopersulfate, ifpresent is added in said hydrophilic mixture as last step. A hydrophobic mixture is prepared which comprises Dobanol R 91-2.5 and acetyl triethyl citrate, if present and dibenzoyl peroxide, if present.

15 Then said hydrophobic mixture is poured into said hydrophilic mixture, while mixing .

Claims

1. An aqueous emulsion having a pH of no more than 7, comprising a hydrophobic liquid ingredient and an emulsifying system comprising a hydrophilic amine oxide surfactant and a hydrophobic surfactant.

2. An emulsion according to claim 1 wherein said hydrophobic liquid ingredient is a bleach activator, a hydrophobic source of active oxygen, a perfume, a hydrophobic solvent, an enzyme, a hydrophobic radical scavenger, a hydrophobic chelating agent, a polymer, or mixtures thereof.

3. An emulsion according to any of the preceding claims wherein said hydrophobic liquid ingredient is a hydrophobic source of active oxygen preferably selected from the group of hydrophobic dialkylperoxides, hydrophobic diacylperoxide, hydrophobic preformed percarboxylic acids, hydrophobic organic and inorganic peroxides, or mixtures thereof, and/or a bleach activator preferably selected from the group of tetracetyl ethylene diamine, sodium 3,5,5 trimethyl hexanoyloxybenzene sulphonate, diperoxy dodecanoic acid, nonylamide of peroxyadipic acid, n-nonanoyloxybenzenesulphonate, N-acyl caprolactams, acetyl triethyl citrate or mixtures thereof.

4. An emulsion according to any of the preceding claims wherein said emulsion comprises from 0.1% to 40% by weight of the total emulsion of said hydrophobic liquid ingredient, or mixtures thereof, preferably from 0.1% to 20% and more preferably from 0.1% to 15%.

5. An emulsion according to any of the preceding claims wherein said emulsion further comprises a hydrophilic source of active oxygen selected from the group of hydrogen peroxide, persulfate, persulfuric acid, percarbonates, metal hydrophilic peroxides, perborates, persilicate salts, or mixtures thereof, and preferably is hydrogen peroxide or monopersulfate.

6. An emulsion according to claim 7 wherein said emulsion comprises from 0.1% to 30% by weight of the total emulsion of said hydrophilic source of active oxygen or mixtures thereof, preferably from 0.1% to 20% and more preferably from 0.1 % to 15%.

7. An emulsion according to any of the preceding claims wherein said hydrophobic surfactant is a surfactant having an HLB up to 11, preferably below 10, and more preferably below 9.

8 An emulsion according to any of the preceding claims wherein said hydrophobic surfactant is a nonionic surfactant.

9. An emulsion according to any of the preceding claims wherein said emulsion comprises from 0.1 % to 30% by weight of the total emulsion of said hydrophobic surfactant or mixtures thereof, preferably from 1% to 15% and more preferably from 1% to 10%.

10. An emulsion according to any of the preceding claims wherein said hydrophilic amine oxide surfactant is an amine oxide surfactant having the following formula R1R2R3NO wherein R1 a linear or branched C6 to C24 alkyl group, being saturated or unsaturated, preferably a C6 to C18 alkyl group and more preferably a C6 to C12, and wherein R2 and R3 are independently substituted or unsubstituted, linear or branched alkyl groups of from 1 to 4 carbon atoms, preferably of from 1 to 3 carbon atoms and more preferably are methyl groups.

11. An emulsion according to any of the preceding claims wherein said emulsion comprises from 0.1% to 40% by weight of the total emulsion of said hydrophilic amine oxide surfactant or mixtures thereof, preferably from 0.5% to 30% and more preferably from 1%
to 10%.

12. An emulsion according to any of the preceding claims which has a pH
below 7, preferably of from 0 to 5 and more preferably of from 0 to 4.

13. A process for the manufacture of an emulsion according to any of the preceding claims wherein:

- a hydrophobic mixture is prepared which comprises at least said hydrophobic surfactant, and said hydrophobic liquid ingredient or mixtures thereof;
- a hydrophilic mixture is prepared which comprises at least water, said hydrophilic amine oxide surfactant and said hydrophilic source of active oxygen, if present;
- said hydrophobic mixture and said hydrophilic mixture are mixed together.