WO2013150301A2

WO2013150301A2 - Composition

Info

Publication number: WO2013150301A2
Application number: PCT/GB2013/050876
Authority: WO
Inventors: Phillip Loraine COTRELL
Original assignee: Innospec Limited
Priority date: 2012-04-04
Filing date: 2013-04-03
Publication date: 2013-10-10
Also published as: GB201215159D0; WO2013150300A3; WO2013150301A3; WO2013150300A2

Abstract

A low irritancy cleansing composition comprising: (a) one or more anionic surfactants; and (b) one or more amphoteric surfactants including a sugar moiety.

Description

Composition

The present invention relates to low irritancy cleansing compositions, for example compositions suitable for use as baby shampoos, baby baths, mild skin cleansers, mild facial cleansers, cleansers for sensitive skin and the like. Such compositions must exhibit low skin and eye irritation. Low irritancy cleansing compositions of this type may also be useful in animal applications, for example as pet shampoos.

In addition to being mild and having low irritancy such compositions must still be efficient cleansing agents. They should be able to effectively remove dirt, grease and other residues from the skin and/or hair. In addition it is desirable to provide high foaming cleansing compositions as these have increased consumer appeal.

According to a first aspect of the present invention there is provided a low irritancy cleansing composition comprising:

(a) one or more anionic surfactants; and

(b) one or more amphoteric surfactants including a sugar moiety.

Preferred features of the invention will now be described. Component (a) comprises one or more anionic surfactants and component (b) comprises one or more amphoteric surfactants.

For the avoidance of doubt, in this specification if reference is made to "the" or "a" amphoteric surfactant including a sugar moiety, such reference includes all such compounds present in the composition.

Component (a) comprises one or more anionic surfactants. Component (a) may comprise any suitable anionic surfactant. Such surfactants will be known to the person skilled in the art.

Component (a) may suitably be selected from one or more of substituted and unsubstituted acyl isethionate compounds; salts of fatty acids; mono- or dialkyl sulfates; mono- or dialkyl ether sulfates; lauryl ether sulfates; alkyi sulfonates; alkyi aryl sulfonates; primary alkane disulfonates; alkene sulfonates; hydroxyalkane sulfonates; alkyi glyceryl ether sulfonates; alpha-olefinsulfonates; alkyi phosphates; sulfonates of alkylphenolpolyglycol ethers; alkyi sulfopolycarboxylic acid esters; alkyi sulfosuccinates, alkyi ether sulfosuccinates, non-acylated alkyi isethionates; fatty acid taurates; acyl taurates; products of condensation of fatty acids with oxy- and aminoalkanesulfonic acids; sulfated derivatives of fatty acids and polyglycols; alkyi and acyl sarcosinates; sulfoacetates; alkyi phosphates; alkyi phosphate esters; acyl lactates; alkanolamides of sulfated fatty acids and lipoamino acids. Particularly exemplary salts of the above, are the sodium, potassium, ammonium, magnesium and triethylamine salts.

Component (a) is preferably selected from one or more of substituted and unsubstituted acyl isethionate compounds; salts of fatty acids; mono- or dialkyl sulfates; alkyi sulfonates; alkyi aryl sulfonates; primary alkane disulfonates; alkene sulfonates; hydroxyalkane sulfonates; alkyi glyceryl ether sulfonates; alpha-olefinsulfonates; alkyi phosphates; alkyi sulfopolycarboxylic acid esters; alkyi sulfosuccinates; non-acylated alkyi isethionates; fatty acid taurates; acyl taurates; products of condensation of fatty acids with oxy- and aminoalkanesulfonic acids; sulfated derivatives of fatty acids and polyglycols; alkyi and acyl sarcosinates; sulfoacetates; alkyi phosphates; alkyi phosphate esters; acyl lactates; lipoamino acids. In preferred embodiments, component (a) is selected from one or more of substituted or unsubstited acyl isethionate compounds, alkyi ether sulphates, alkyi sulfates, and taurate surfactants. These are suitably present as alkali metal or ammonium salts. Sodium salts are preferred. In some embodiments, component (a) is selected from one or more of substituted or unsubstituted acyl isethionate compounds, alkyi ether sulfates and alkyi sulfates.

In some embodiments component (a) comprises a substituted or unsubstituted isethionate compound, that is a compound of formula (I):

(I)

wherein R¹ represents a C₄-₃₆ substituted or unsubstituted hydrocarbyl group;

each of R², R³, R⁴ and R⁵ independently represents a hydrogen atom or a C_1-4 alkyi group and M⁺ represents a cation.

Preferably R¹ is selected from a substituted or unsubstituted alkyi, alkenyl, aryl or alkylaryl group. More preferably R¹ is selected from a substituted or unsubstituted alkyi or alkenyl group. Most preferably R¹ is an unsubstituted alkyi or alkenyl group, especially an unsubstituted alkyi group. Preferably R¹ represents a C5.30 alkyl group, preferably a C₇.₂4 alkyl group, more preferably a C7-21 alkyl group, most preferably a C7.17 alkyl group.

In some embodiments R², R³, R⁴ and R⁵ are all hydrogen. However in preferred embodiments at least one of R², R³, R⁴ and R⁵ is not hydrogen.

Preferably R² represents a C_{1 -4} alkyl group, suitably a C_1-4 alkyl group in which a propyl or butyl group, when present, is straight-chained. Preferably R² represents an n-propyl, ethyl or, most preferably, a methyl group.

Preferably R³ represents a hydrogen atom.

Preferably one of R⁴ and R⁵ represents a hydrogen atom and the other represents a hydrogen atom or a C_1-4 alkyl group. Preferably one of R⁴ and R⁵ represents a hydrogen atom or a C_1-4 alkyl group in which a propyl or butyl group is straight-chain. Preferably one of R⁴ and R⁵ represents an n-propyl, ethyl or methyl group or, most preferably, a hydrogen atom. Most preferably both R⁴ and R⁵ represent hydrogen atoms.

In some embodiments the composition of the present invention may include a mixture of more than one compound of formula (I). For example an isomeric mixture of compounds of formula (I) may be present. Such a mixture may include, for example a compound in which R² is alkyl (suitably methyl) and R³, R⁴ and R⁵ are all hydrogen and a compound in which R⁵ is is alkyl (suitably methyl) and R², R³ and R⁴ are all hydrogen. In some embodiments component (a) may comprise a mixture of compounds including compounds in which R², R³, R⁴ and R⁵ are all hydrogen and compounds in which one of R², R³, R⁴ and R⁵ is a to C₄ alkyl (especially methyl) and the others are hydrogen.

Preferably M⁺ represents an optionally substituted ammonium cation or, most preferably, a metal cation. Suitable ammonium cations include NH₄ ⁺ and the ammonium cation of triethanolamine. Suitable metal cations include zinc, alkali metal cations, for example sodium, lithium and potassium cations, and alkaline earth metal cations, for example calcium and magnesium cations. Preferably M⁺ represents a potassium cation, or, especially, a sodium cation.

R¹ may be an alkyl group or an alkenyl group. Preferably R¹ is an alkyl group. In some embodiments the component surfactant of the present invention may comprise a mixture of fatty acids to form a mixture of compounds of formula (I) in which R¹ may be different. R¹ is preferably the residue of a fatty acid. Fatty acids obtained from natural oils often include mixtures of fatty acids. For example the fatty acid obtained from coconut oil contains a mixture of fatty acids including C₁₂ lauric acid, d₄ myristic acid, Ci₆ palmitic acid, C₈ caprylic acid, and C₁₈ stearic and oleic.

R¹ may include the residue of one or more naturally occurring fatty acids and/or of one or more synthetic fatty acids. In some preferred embodiments R¹ consists essentially of the residue of a single fatty acid. Examples of carboxylic acids from which R¹ may be derived include coco acid, butyric acid, hexanoic acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, arachidic acid, gadoleic acid, arachidonic acid, eicosapentanoic acid, behinic acid, eruic acid, docosahexanoic lignoceric acid, naturally occurring fatty acids such as those obtained from coconut oil, tallow, palm kernel oil, butterfat, palm oil, olive oil, corn oil, linseed oil, peanut oil, fish oil and rapeseed oil ; synthetic fatty acids made as chains of a single length or a selected distribution of chain lengths; and mixtures thereof. Most preferably R¹ comprises the residue of lauric acid, that is a saturated fatty acid having 12 carbon atoms or the residue of mixed fatty acids derived from coconut oil. The compound of formula (I) may be prepared by any of the methods disclosed in the prior art, for example see the methods described in WO94/09763 and WO2005/075623.

As mentioned above in some embodiments R², R³ R⁴ and R⁵ are all hydrogen. Preferred compounds of this type include sodium lauroyl isethionate and sodium cocoyl isethionate.

In especially preferred embodiments, R³, R⁴ and R⁵ are all hydrogen and R² is ethyl or, most preferably methyl.

In such preferred embodiments the composition of the present invention preferably comprises the reaction product of sodium methyl isethionate and a fatty acid, that is a compound of formula (MA) or (MB):

R¹COOCH(CH₃)CH₂S0₃ ^"M⁺

(MA)

R¹COOCH₂CH(CH₃)S0₃ ^~M

(MB)

Mixtures of these isomers may be present. In some embodiments the composition of the present invention comprises one or more of sodium lauroyl methyl isethionate, sodium cocoyl methyl isethionate and sodium oleoyl methyl isethionate.

In some embodiments component (a) of the composition of the present invention comprises sodium lauroyl methyl isethionate and/or sodium cocoyl methyl isethionate. Sodium lauroyl methyl isethionate is especially preferred. Component (a) of the compositions of the present invention may comprise a compound of formula(l). It may include a mixture of two or more such compounds. In such embodiments preferably at least 30%wt of component (a) is made up of compounds in which at least one of R², R³, R⁴ and R⁵ is not hydrogen, preferably at least 50%wt, suitably at least 70%wt, for example at least 80%wt or at least 90%wt.

In some preferred embodiments components (a) does not comprise a substituted or unsubstituted acyl isethionate compound.

In some embodiments the composition of the present invention does not comprise a substituted or unsubstituted acyl isethionate compound.

In some embodiments the composition of the present invention comprises less than 5 wt% acyl isethionate compounds, for example less than 2.5 wt%, suitably less than 1 wt%, preferably less than 0.5 wt%, for example less than 0.1 wt% or less than 0.01 wt%.

Suitably component (a) may be selected from one or more of salts of fatty acids; mono- or dialkyl sulfates; mono- or dialkyl ether sulfates; lauryl ether sulfates; alkyl sulfonates; alkyl aryl sulfonates; primary alkane disulfonates; alkene sulfonates; hydroxyalkane sulfonates; alkyl glyceryl ether sulfonates; alpha-olefinsulfonates; alkyl phosphates; sulfonates of alkylphenolpolyglycol ethers; alkyl sulfopolycarboxylic acid esters; alkyl sulfosuccinates, alkyl ether sulfosuccinates, non-acylated alkyl isethionates; fatty acid taurates; acyl taurates; products of condensation of fatty acids with oxy- and aminoalkanesulfonic acids; sulfated derivatives of fatty acids and polyglycols; alkyl and acyl sarcosinates; sulfoacetates; alkyl phosphates; alkyl phosphate esters; acyl lactates; alkanolamides of sulfated fatty acids and lipoamino acids. Particularly exemplary salts of the above are the sodium, potassium, ammonium, magnesium and triethylamine salts.

In some preferred embodiments component (a) is selected from one or more of salts of fatty acids; mono- or dialkyl sulfates; alkyl sulfonates; alkyl aryl sulfonates; primary alkane disulfonates; alkene sulfonates; hydroxyalkane sulfonates; alkyl glyceryl ether sulfonates; alpha-olefinsulfonates; alkyl phosphates; alkyl sulfopolycarboxylic acid esters; alkyl sulfosuccinates; non-acylated alkyl isethionates; fatty acid taurates; acyl taurates; products of condensation of fatty acids with oxy- and aminoalkanesulfonic acids; sulfated derivatives of fatty acids and polyglycols; alkyl and acyl sarcosinates; sulfoacetates; alkyl phosphates; alkyl phosphate esters; acyl lactates; lipoamino acids.

Component (a) may suitably be selected from alkyl ether sulfates, alkyl sulfates and taurate surfactants.

In some preferred embodiments component (a) is selected from alkyl ether sulfates and alkyl sulfates.

Preferred alkyl ether sulphate surfactants are compounds of formula R¹ ((CH₂)_nO)_mS0₃ ^~M⁺ wherein R¹ is an alkyl group of 1 to 36 carbon atoms, n is from 1 to 6, m is from 1 to 1 00 and M⁺ is an ammonium or alkali metal cation.

R¹ is preferably an alkyl group having 4 to 32 carbon atoms, preferably from 4 to 28 carbon atoms, suitably from 6 to 24 carbon atoms, preferably from 8 to 22 carbon atoms, more preferably from 8 to 20 carbon atoms, more preferably from 8 to 20 carbon atoms, for example from 8 to 16 carbon atoms or from 10 to 14 carbon atoms. n is preferably from 1 to 4, preferably 2 or 3. Most preferably n is 2. m is preferably from 1 to 50, more preferably from 1 to 20, suitably from 1 to 10, preferably from 1 to 6, more preferably from 1 to 4, most preferably m is 2.

M⁺ is preferably an alkali metal or ammonium cation, suitably potassium, NH₄ ⁺ or sodium. Most preferably M⁺ is a sodium ion.

An especially preferred alkyl ether sulphate surfactant is sodium lauryl ether sulphate, preferably including two ethoxy residues.

Suitable alkyl sulphate surfactants include compounds of formula R¹S0₃M⁺ wherein R¹ is an alkyl group having 1 to 36 carbon atoms and M⁺ is an alkali metal or ammonium ion.

R¹ is preferably an alkyl group having 4 to 32 carbon atoms, preferably from 4 to 28 carbon atoms, suitably from 6 to 24 carbon atoms, preferably from 8 to 22 carbon atoms, more preferably from 8 to 20 carbon atoms, more preferably from 8 to 20 carbon atoms, for example from 8 to 16 carbon atoms or from 10 to 14 atoms.

Especially preferred alkyl sulphate surfactants include ammonium lauryl sulphate and especially sodium lauryl sulphate. In some embodiments, component (a) may be selected from substituted and unsubstituted isethionate compounds, alkyl sulphates, alkyl ether sulphates and mixtures thereof.

Component (a) may suitably be selected from sodium lauroyl methyl isethionate, sodium lauryl sulphate and sodium lauryl diethoxy sulphate.

Component (b) comprises one or more amphoteric surfactants including a sugar moiety.

By "including a sugar moiety" we mean that the amphoteric surfactant molecule includes the residue of at least one monosaccharide unit. For the avoidance of doubt the monosaccharide unit may in some embodiments be part of a oligosaccharide or polysaccharide unit.

Suitably the amphoteric surfactant of component (b) includes at least one substituted monosaccharide unit. It may contain one or more substituted monosaccharide units selected from glucose, mannose and galactose. Preferably it includes at least one substituted glucose unit.

Component (b) is an amphoteric surfactant. By this we mean to include any surfactants having the ability to exhibit both positive and negative sites. The amphoteric surfactant may typically include a cationic group and an anionic group. Suitable cationic groups include quaternary ammonium groups. Suitable anionic groups include the residues of carboxylic acids (carboxylate groups) and sulfonic acids (sulfonate groups). The amphoteric surfactant may be selected from surfactants referred to as betaines, including sultaines (sulphobetaines), or other zwitterionic or amphoteric surfactants, for example those based on fatty nitrogen derivatives. In this specification the term "amphoteric group" may be used to refer to a moiety including a cationic group and an anionic group.

Preferably the amphoteric surfactant component (b) includes at least one quaternary ammonium group and at least one anionic group selected from carboxylate groups and sulfonate groups.

Preferably the amphoteric surfactant of component (b) includes at least one quaternary ammonium group and at least one carboxylate group.

Suitably the amphoteric surfactant of component (b) includes at least one substituted monosaccharide unit, at least one quaternary ammonium group and at least one carboxylate group. The amphoteric surfactant (b) preferably includes at least one monosaccharide unit. It may include a disaccharide, oligosaccharride or polysaccharide unit. Sutable polysaccharides include starches and guar. These may be unsubstituted or substituted with one or more alkyl groups. Preferably they are substituted, preferably with one alkyl group. The amphoteric surfactant may include one or more monosaccharide units, dissacharide units, oligosaccharide units or polysaccharide units. The term saccharide unit may be used herein to refer to any of these.

The or each saccharide unit may be optionally substituted with one or more hydrocarbyl groups. Each saccharide unit may be optionally substituted with one or more alkyl or alkenyl groups. Suitably the alkyl or alkenyl substituent comprises from 1 to 40 carbon atoms, preferably from 4 to 36 carbon atoms, suitably from 4 to 32 carbon atoms, preferably from 6 to 28 carbon atoms, for example 6 to 24 carbon atoms or 8 to 22 carbon atoms. Preferably the or each saccharide unit may be substituted with one or more alkyl groups. Preferably each saccharide unit is substituted with one alkyl group.

Component (b) suitably comprises a substituted polyglycoside compound, preferably a substituted polyglucoside.

Preferably component (b) comprises a polyglycoside substituted with a hydrocarbyl group, for example an alkyl, alkenyl or aralkyl group. Suitably component (b) may be an alkyl polyglycoside compound including at least one amphoteric group.

In some especially preferred embodiments component (b) is an alkyl polyglucoside compound including at least one amphoteric group.

Substituted polyglycosides are compounds having the structure shown in figure (III):

(III) in which each R is independently alkyl, alkenyl, aralkyl or hydrogen and R' is alkyl, alkenyl or aralkyl. Preferably R' is alkyl. Preferably each R is hydrogen. Such compounds and the synthesis thereof will be known to the person skilled in the art. In the structure shown in figure (III), x may be 0 or a positive integer. Commerical sources of these compounds typically contain mixtures and on average x is between 0 and 2, usually between 0 and 1 , for example about 0.5. A common term used with respect to these type of compounds is the degree of polymerisation. When x is 0, the degree of polymerisation is 1 . When x is 1 the degree of polymerisation is 2. Suitably the degree of polymerisation of the alkyl polyglycosides used in the present invention is from 1 to 2, for example about 1 .4.

Alkyl polyglycosides are available commercially. For example lauryl glucoside, coco glucoside and decyl glucoside are available from Cognis as Plantaren (RTM) 1200 N UP, Plantacare (RTM) 818 UP and Plantaren (RTM) 2000 N UP.

Alkyl polyglycosides may be functionalised by linking a functional group to one or more of the residual hydroxy groups of the sugar moiety. Component (b) of the composition of the present invention preferably comprises an alkyl polyglycoside compound in which an amphoteric group is linked to one or more of the hydroxy groups of the sugar moiety. The amphoteric group may be joined to the sugar residue via a suitably linking group. In some embodiments the same or a different linking group may also link sugar residues to each other, and thus the compounds may be regarded as cross-linked functionalised polyglycosides. Suitable linking groups will be known to the person skilled in the art and include optionally substituted alkylene groups, for example -CH₂CH(OH)CH₂-. These linking groups may be provided by reaction of alkyl polyglycosides and amphoteric group precursor compounds with a difunctionalised alkyl group, for example 1 ,3-dichloropropan-2-ol. Other suitable compounds will be known to the person skilled in the art.

In preferred embodiments component (b) comprises an alkyl polyglycoside including a quaternary ammonium group and either a sulfonate group or a carboxylate group.

Thus component (b) may comprise a sultaine functionality and/or a betaine functionality.

In some embodiments component (b) may comprise an alkylpolyglycoside including a sultaine functionality.

Preferably component (b) comprises an alkypolyglycoside including a betaine functionality.

The synthesis of the functionalised cross-linked alkyl polyglycosides including an amphoteric group may be achieved by methods known from the prior art.

The synthesis of betaine functionalised saccharides is described for example in US5124446, the entire teaching of which is incorporated herein by reference.

US5124445 describes the preparation of polysaccharides containing betaine groups particularly those based on hydroxyethyl cellulose. The synthesis involves reacting the polysaccharide with an intermediate compound which is the reaction product of epichlorohydrin with a tertiary amino acid and has the formula:

The synthesis of crosslinked functionalised alkyl polyglycosides is described for example in US8124575, the entire teaching of which is incorporated herein by reference. US8124575 teaches a series of polyglycoside derivatives that are copolymerised/crosslinked with hydroxypropyl linkages and contain additional functionalised groups. US8124575 also teaches the crosslinking of mixtures of alkyi polyglycosides and non alkyi substituted saccharides such as sugars with hydroxpropyl linkages. The crosslinking/polymerising agent is 1 ,3-dichloropropan-2-ol, CICH₂CH(OH)CH₂CI.

US7375064 teaches a series of polyglycoside derivatives that are copolymerised/crosslinked with CICH₂CH(OH)CH₂0(CH₂CH₂0)_a(CH₂CH(CH₃)0)_bCH₂CH(OH)CH₂CI where a is an integer ranging from 1 to 20 and b is an integer ranging from 1 to 20.

In some preferred embodiments component (b) comprises a compound represented by formula (IV):

wherein R¹ is a C₄ to C₃₆ substituted or unsubstituted hydrocarbyl group; each R² is a moiety including an amphoteric group; each S is a saccharide unit; n is an integer from 0 to 3; each L is a linking group; m is at least 1 ; each T is a terminal group, and each p may be 0 or a positive integer, provided at least one p is a positive integer.

Preferably R¹ is a substituted or unsubstituted alkyi or alkenyl group. Preferably R¹ is an unsubstiututed alkyi or alkenyl group, especially an unsubstituted alkyi group.

Preferably R¹ is a C₄ to C₃₆ alkyi group, preferably a C₆ to C₃₂ alkyi group, preferably a C₆ to C₂₈ alkyi group, more preferably a C₈ to C₂₄ alkyi group, most preferably a C₈ to Ci₈ alkyi group.

Preferably R¹ is a lauryl group or a mixture of alkyi groups derived from coconut oil.

Each S is a saccharide unit. Each S may independently be a monosaccharide unit, a dissacharide unit, an oligosaccharide unit or a polysaccharide unit. Preferably S is selected from monosaccharides, dissacharides and mixtures thereof. Preferably each S includes a glucose unit. n is preferably 1 or 2, most preferably n is 1 Each L is a linking group. L may be a bond. For example at a terminal group L may be a bond to a hydrogen atom. In some embodiments L may be an optionally substituted alkylene or alkenylene group. Suitably L is an optionally substituted alkylene group. In some preferred embodiments L is a hydroxy substituted alkylene group. In an especially preferred embodiment L is -CH₂CH(OH)CH₂-. T is a terminal group. T may be an alkyl group. Preferably T is hydrogen. p is at least 1 . When S is a monosaccharide p is preferably 1 or 2. If S includes more than one monosaccharide group, for example if S is a disaccharide or an oligosaccharide p may be more than 2, for example more than 5. m is at least 1 . In some embodiments m is from 1 to 4, for example from 1 to 2.

In some embodiments m is much larger and the compound of formula (IV) includes many cross-linked units. For example the compounds of formula (IV) may have an average molecular weight of from 200 to 500,000, for example from 500 to 200,000 suitably from 500 to 100,000, suitably from 1 ,000 to 60,000, preferably from 5,000 to 50,000, more preferably from 8,000 to 25,000, suitably from 10,000 to 20,000.

In some preferred embodiments, the compounds of formula (IV) may have an average molecular weight of from 200 to 10,000, preferably 500 to 5,000 for example 500 to 2,000.

In some preferred embodiments, the compounds of formula (IV) may have an average molecular weight of from 50,000 to 300,000, preferably 100,000 to 200,000. In some alternative embodiments, for example when the compound is based on high molecular weight polysaccharides for example guars, the compound of formula (IV) may have a much higher molecular weight, for example in excess of 1 ,000,000.

In other preferred embodiments, the compounds of formula (IV) may be mixtures having bi- or multimodal molecular weight distributions comprising one or more of the above preferred molecular weight ranges.

R² is a moiety including an amphoteric group. In some preferred embodiments R² may be represented by the group: R³ X N- Y Z

R⁴ wherein R³ and R⁴ is each independently a Ci to C₃₆ substituted or unsubstituted alkyl, alkenyl or aryl group; X is an optionally substituted alkylene, alkenylene or arylene group; Y is an optionally substituted alkylene, alkenylene or arylene group; and Z is COO^" or S0₃ ^"

Preferably each of R³ and R⁴ is independently a to C₃₆ substituted or unsubstituted alkyl or alkenyl group. Preferably R³ and R⁴ is each independently a substituted or unsubstituted alkyl group, preferably having from 1 to 30 carbon atoms, preferably 1 to 24 carbon atoms, preferably 1 to 1 8 carbon atoms, more preferably 1 to 12 carbon atoms, suitably 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms.

Suitably R³ and R⁴ is each independently an unsubstituted alkyl group or a hydroxy substituted alkyl group. For example R³ and R⁴ may each independently be selected from methyl, ethyl, propyl, butyl, hydroxymethyl, hydroxyethyl, hydroxypropyl and hydroxybutyl.

In some especially preferred embodiments R³ is hydroxyethyl and R⁴ is hydroxyethyl. X is an optionally substituted alkylene, alkenylene or arylene group. Preferably X is an optionally substituted alkylene or alkenylene group. Preferably X is an optionally substituted alkylene group. In some preferred embodiments X is a hydroxy substituted alkylene group. In an especially preferred embodiment X is -CH₂CH(OH)CH₂-. In some preferred embodiments X is the same as L.

Y is an optionally substituted alkylene, alkenylene or arylene group. Preferably Y is an optionally substituted alkylene or alkenylene group. Preferably Y is an optionally substituted alkylene group.

When Z is COO^", Y is preferably an unsubstituted alkylene group, most preferably CH₂.

When Z is S0₃ ^", Y is preferably a substituted alkylene group, most preferably

-CH₂CH(OH)CH₂-.

In some embodiments R² may be the group:

where R , X, Y and Z are as defined above. In some embodiments R² may be the group:

1 +

-X N Y-

X S where R³, X, Y, Z and S are as defined above.

The skilled person will appreciate that under some conditions of pH one or both of the groups Z may be protonated.

The structure shown in figure (IV) is a simple representation of some of the compounds, used in the present invention. The skilled person would appreciate commercial sources of these compounds typically contain complex mixtures. Compounds falling inside and outside the definitions of this structure may be present in component (b) of the composition of the present invention.

In some embodiments component (b) used in the composition of the present invention may include compounds of formula (V):

(V) wherein each of R¹ , R², R³, R⁴, R⁵, R⁶, R⁷ and R⁸ is independently selected from hydrogen, a hydrocarbyl group, a moiety including an amphoteric group or a cross-link to another saccharide unit, and n is 0 or a positive integer, provided that the molecule includes at least one hydrocarbyl group and at least one amphoteric group.

Preferred hydrocarbyl groups are alkyl groups, especially unsubstituted alkyl groups. The alkyl groups preferably have from 1 to 36 carbon atoms, preferably from 6 to 30, more preferably from 8 to 24 carbon atoms. Especially preferred are a lauryl group or a mixture of alkyl groups derived from coconut oil.

In some preferred embodiments R⁸ is an alkyl group.

Each of R¹ , R², R³, R⁴, R⁵, R⁶, R⁷ and R⁸ may include an amphoteric group. Suitable amphoteric groups include those of the formula XN⁺R³R⁴YZ where X, R³, R⁴ and Y and Z are as defined in relation to compound of formula (IV).

The amphoteric groups may be incorporated into the structure by reacting a saccharide compound with a suitably functionalised amphoteric moiety.

The suitably functionalised amphoteric moiety may include a sultaine or preferably a betaine.

Examples of suitably functionalised betaines include compounds formed by the reaction of epichlorohydrin and a tertiary amino acid. Some compounds of this type are the reaction product of epichlorohydrin with dimethyl glycine, dimethyl amino undecanoic acid, 3-dimethyl amino-2,2-dimethylpropionic acid or N-butyl-N-methyl amino acetic acid. These compounds are shown in figure (VI):

Figure (VI)

In some embodiments one or more R¹ , R², R³, R⁴, R⁵, R⁶, R⁷ and R⁸ may be a cross-link to another saccharide unit. In some embodiments the cross-link may be a bond. However preferred cross-linking groups are optionally substituted alkylene, alkenylene and arylene groups. Especially preferred embodiments are substituted alkyl groups. Suitable cross-linking agents are difunctionalised alkyl groups which are able to react with the hydroxyl groups on two different saccharide units. It would be possible to use trifunctionalised cross-linking groups able to react with hydroxyl groups on three saccharide units. However this is not preferred. Suitable difunctionalised cross-linking agents include epichlorohydrin, 1 ,3- dichloropropan-2-ol and CICH₂CH(OH)CH₂0(CH₂CH₂0)_a(CH₂CH(CH₃)0)_bCH₂CH(OH)CH₂CI wherein each of a and b is an integer from 1 to 20. 1 ,3-dichloropropanol is especially preferred.

Each of R¹ , R², R³, R⁴, R⁵, R⁶, R⁷ and R⁸ may be hydrogen. As the skilled person will appreciate R¹ is unlikely to be hydrogen. R¹ may suitably include a betaine moiety. Preferably at least one of R², R³ and R⁴ is hydrogen. Preferably at least one of R⁵, R⁶ and R⁷ is hydrogen.

The hexose residues shown in formula (V) may suitably be selected from glucose, mannose and galactose residues. Glucose residues are especially preferred.

The compound of formula (V) is preferably an alkyl polyglycoside functionalised with betaine groups and cross-linked with linking groups. In preferred compounds of formula (V) the alkyl polyglycoside is preferably lauryl or coco polyglycoside, preferably lauryl. In preferred compounds of formula (V) the betaine group is a bishydroxyethylglycinate.

In preferred compounds of formula (V) the linking group is -CH₂CH(OH)CH₂-. Especially preferred compounds of formula (V) include the moiety CH₂CH(OH)CH₂N⁺(CH₂CH₂OH)₂CH₂COO^".

In some preferred embodiments component (b) includes a compound of formula (VII):

(VII)

Compounds having this structure are commercially available under the trade mark Poly SugaBetaine L from Colonial Chemicals.

The inventors have surprisingly found that the irritancy of the compositions of the present invention may be reduced by the inclusion of one or more further surfactants in addition to components (a) and (b).

Thus in some embodiments the low irritancy cleansing composition of the present invention preferably comprises at least one further surfactant component in addition to component (a) and component (b). In some embodiments the low irritancy cleansing composition of the present invention comprises at least three different surfactant components.

In some preferred embodiments the low irritancy cleansing composition of the present invention comprises at least four different surfactant components.

In some embodiments the low irritancy cleansing composition of the present invention comprises at least five different surfactant components. In some especially preferred embodiments, the composition of the first aspect further comprises an amphoteric surfactant component (c), in addition to the betaine component (b).

Thus, in preferred embodiment the cleansing composition of the present invention comprises:

(a) an anionic surfactant;

(b) an amphoteric surfactant including sugar moiety; and

(c) a further amphoteric surfactant in addition to component (b). By amphoteric surfactant we mean to include any surfactants having the ability to exhibit both positive and negative sites. The surfactant component (c) may be selected from surfactants referred to as betaines, including sultaines (sulphobetaines), or other zwitterionic or amphoteric surfactants, for example those based on fatty nitrogen derivates. Suitable surfactants for use as component (c) may be selected from betaines, for example alkyl betaines, alkylamidopropyl betaines, alkylamidopropyl hydroxy sultaines, alkylampho acetates, alkylamphodiacetates, alkylamphopropionates, alkylamphodipropionates, alkyliminodipropionates and alkyliminodiacetates. Amphoteric surfactants suitable for use as component (c) in the compositions of the present invention may include those which have an alkyl or alkenyl group of 7 to 22 carbon atoms and comply with an overall structural formula:

where R¹ is alkyl or alkenyl of 7 to 22 carbon atoms; R² and R³ are each independently alkyl, hydroxyalkyl or carboxyalkyl of 1 to 6 carbon atoms; m is 2 to 4; n is 0 or 1 ; X is alkylene of 1 to 6 carbon atoms optionally substituted with hydroxyl; and Y is -C0₂ or -S0₃.

Surfactant component (c) may include simple betaines of formula:

and amido betaines of formula: O

R¹— C— NH(CH₂)_m— N— CHgCOg^"

R³ where m is 2 or 3.

In both formulae R¹ , R² and R³ are as defined previously. R¹ may, in particular, be a mixture of C₁₂ and C₁₄ alkyl groups derived from coconut so that at least half, preferably at least three quarters, of the groups R¹ has 10 to 14 carbon atoms. R² and R³ are preferably methyl.

Amphoteric surfactant component (c) may include sultaines (or sulphobetaines) of formula:

where m is 2 or 3, or variants of these in which

-(CH₂)₃S0₃ ^" is replaced by

OH

I

-CH₂-CH-CH₂S0₃ where R¹ , R² and R³ in these formulae are as defined previously. Amphoteric or zwitterionic surfactants may include amphoacetates and diamphoacetates. Amphoacetates generally conform to the following formula:

Diamphoacetates generally conform to the following formula:

CH₂COO^~ M

RCON ICH₂CH₂N— CH₂CH₂OH

CH₂COO^~M⁺ where R is an aliphatic group of 8 to 22 carbon atoms and M is a cation such as sodium, potassium, ammonium, or substituted ammonium. Suitable acetate-based amphoteric surfactants include lauroamphoacetate; alkyi amphoacetate; cocoampho(di)acetate; cocoamphoacetate; disodium cocoamphodiacetate; sodium cocoamphoacetate; disodium cocoamphodiacetate; disodium capryloamphodiacete; disodium lauroamphoacetate; sodium lauroamphoacetate and disodium wheatgermamphodiacetate.

Suitable betaine surfactants include alkylamido betaine; alkyi betaine, C₁₂/14 alkyldimethyl betaine; cocoamidopropylbetaine; tallow bis(hydroxyethyl) betaine; hexadecyldimethylbetaine; cocodimethylbetaine; alkyi amido propyl sulfo betaine; alkyi dimethyl amine betaine; coco amido propyl dimethyl betaine; alkyi amido propyl dimethyl amine betaine; cocamidopropyl betaine; lauryl betaine; laurylamidopropl betaine, coco amido betaine, lauryl amido betaine, alkyi amino betaine; alkyi amido betaine; coco betaine; lauryl betaine; diemethicone propyl PG-betaine; oleyl betaine; N-alkyldimethyl betaine; coco biguamide derivative, C₈ amido betaine; Ci₂ amido betaine; lauryl dimethyl betaine; alkylamide propyl betaine; amido betaine; alkyi betaine; cetyl betaine; oleamidopropyl betaine; isostearamidopropyl betaine; lauramidopropyl betaine; 2-alkyl-A/-carboxymethyl-A/-hydroxyethyl imidazolinium betaine; 2- alkyl-A/-carboxyethyl-A/-hydroxyethyl imidazolinium betaine; 2-alkyl-A/-sodium carboxymethyl- A/-carboxymethyl oxyethyl imidazolinium betaine; A/-alkyl acid amidopropyl-A/,A/-dimethyl-A/-(3- sulfopropyl)-ammonium-betaine; A/-alkyl-A/,A/-dimethyl-A/-(3-sulfopropyl)-ammonium-betaine; cocodimethyl betaine; apricotamidopropyl betaine; isostearamidopropyl betaine; myristamidopropyl betaine; palmitamidopropyl betaine; cocamidopropyl hydroxy sultaine; undecylenamidopropyl betaine; cocoamidosulfobetaine; alkyi amido betaine; Ci_2/is alkyi amido propyl dimethyl amine betaine; lauryldimethyl betaine; ricinol amidobetaine; tallow aminobetaine. Suitable glycinate-based amphoteric surfactants include cocoamphocarboxyglycinate; tallowamphocarboxygycinate; capryloamphocarboxyglycinate, oleoamphocarboxyglycinate, bis-2-hydroxyethyl tallow glycinate; lauryl amphoglycinate; tallow polyamphoglycinate; coco amphoglycinate; oleic polyamphoglycinate; N-C_{wn 2} fatty acid amidoethyl-A/-(2-hydroxyethyl)- glycinate; A -C_{1 2}/i 8-fatty acid amidoethyl-N-(2-hydroxyethyl)-glycinate; dihydroxyethyl tallow glycinate.

In preferred embodiments component (c) comprises a betaine. An especially preferred betaine surfactants for use as component (c) is cocoamidopropyl betaine.

In preferred embodiments the cleansing composition of the present invention comprises:

- an anionic surfactant selected from substituted and unsubstituted isethionate compounds, alkyi sulfates, alkyi ether sulfates and mixtures thereof;

an alkyi polyglycoside including at least one betaine moiety; and

a further betaine surfactant. In some embodiments the cleansing composition of the present invention comprises:

an anionic surfactant selected from alkyi sulfates, alkyi ether sulfates and mixtures thereof;

an alkyi polyglycoside including at least one betaine moiety; and

a further betaine surfactant.

The composition of the present invention may comprise further surfactant components in addition to components (a), (b) and (c).

Such surfactants may be selected from anionic surfactants, cationic surfactants, amphoteric surfactants, non-ionic surfactants and mixtures thereof.

In some preferred embodiments the composition of the present invention comprises a further anionic surfactant (d) in addition to the anionic surfactant of component (a) The additional anionic surfactant (d) is different from the anionic surfactant of component (a). It is preferably selected from one or more of salts of fatty acids; mono- or dialkyi sulfates; mono- or dialkyi ether sulfates; lauryl ether sulfates; alkyi sulfonates; alkyi aryl sulfonates; primary alkane disulfonates; alkene sulfonates; hydroxyalkane sulfonates; alkyi glyceryl ether sulfonates; alpha-olefinsulfonates; alkyi phosphates; sulfonates of alkylphenolpolyglycol ethers; alkyi sulfopolycarboxylic acid esters; alkyi sulfosuccinates, alkyi ether sulfosuccinates, non-acylated alkyi isethionates; fatty acid taurates; acyl taurates; products of condensation of fatty acids with oxy- and aminoalkanesulfonic acids; sulfated derivatives of fatty acids and polyglycols; alkyi and acyl sarcosinates; sulfoacetates; alkyi phosphates; alkyi phosphate esters; acyl lactates; alkanolamides of sulfated fatty acids and lipoamino acids. Particularly exemplary salts of the above, are the sodium, potassium, ammonium, magnesium and triethylamine salts.

Preferred additional anionic surfactants (d) are selected from salts of fatty acids; mono- or dialkyi sulfates; alkyi sulfonates; alkyi aryl sulfonates; primary alkane disulfonates; alkene sulfonates; hydroxyalkane sulfonates; alkyl glyceryl ether sulfonates; alpha-olefinsulfonates; alkyl phosphates; alkyl sulfopolycarboxylic acid esters; alkyl sulfosuccinates; non-acylated alkyl isethionates; fatty acid taurates; acyl taurates; products of condensation of fatty acids with oxy- and aminoalkanesulfonic acids; sulfated derivatives of fatty acids and polyglycols; alkyl and acyl sarcosinates; sulfoacetates; alkyl phosphates; alkyl phosphate esters; acyl lactates; lipoamino acids.

Particularly preferred anionic surfactants for use herein include sodium methyl cocoyl taurate, sodium oleoyl methyl taurate, sodium lauroyl methyl taurate, sodium lauryl sarcosinate, disodium oleamido mipa sulfosuccinate.

Component (d) is preferably selected from alkyl ether sulfates, alkyl sulfates and taurate surfactants. Preferred anionic surfactants (d) are taurate surfactants. Suitably the additional anionic surfactant is selected from sodium methyl lauryl taurate, sodium methyl cocoyl taurate and sodium oleoyl methyl taurate. Sodium oleoyl methyl taurate is especially preferred

Component (a) is preferably present in the cleansing composition of the present invention in an amount of at least 0.1 wt%, preferably at least 0.5 wt%, for example at least 0.75 wt%, suitably at least 1 wt%, preferably at least 1 .5 wt%, for example at least 2 wt%, at least 2.25 wt% or at least 2.5 wt%. Component (a) may be present in an amount of up to 70 wt%, suitably up to 50 wt%, preferably up to 40 wt%, suitably up to 30 wt%, preferably up to 20 wt%, more preferably up to 10 wt%, suitably up to 7.5 wt%, preferably up to 5 wt%, more preferably up to 4.5 wt%, for example or up to 4 wt%, up to 3.75 wt% or up to 3.5 wt%.

Component (b) is preferably present in the cleansing composition of the present invention in an amount of at least 0.1 wt%, preferably at least 0.5 wt%, for example at least 0.75 wt%, suitably at least 1 wt%, preferably at least 1 .5 wt%, more preferably at least 1 .75 wt%, for example at least 2 wt%. Component (b) may be present in an amount of up to 70 wt%, suitably up to 50 wt%, preferably up to 40 wt%, suitably up to 30 wt%, preferably up to 20 wt%, more preferably up to 1 0 wt%, suitably up to 7.5 wt%, preferably up to 5 wt%, suitably up to 4 wt%, suitably preferably up to 3.75 wt%, for example up to 3.5 wt% or up to 3 wt%. Component (c) is preferably present in the cleansing composition of the present invention in an amount of at least 0.1 wt%, preferably at least 0.5 wt%, for example at least 0.75 wt%, suitably at least 1 wt%, preferably at least 1 .5 wt%, more preferably at least 1 .75 wt%, for example at least 2 wt%. Component (c) may be present in an amount of up to 70 wt%, suitably up to 50 wt%, preferably up to 40 wt%, suitably up to 30 wt%, preferably up to 20 wt%, more preferably up to 1 0 wt%, for example up to 7.5 wt% or up to 5 wt%, suitably up to 4 wt%, preferably up to 3.75 wt%, for example up to 3.5 wt% or up to 3 wt%.

Component (d) is preferably present in an amount of at least 0.1 wt%, suitably at least 0.5 wt%, preferably at least 0.75 wt%, more preferably at least 1 wt%, for example at least 1 .25wt% or at least 1 .5 wt%. Component (d) may be present in an amount of up to 70 wt%, preferably up to 50 wt%, suitably up to 30 wt%, preferably up to 20 wt%, more preferably up to 15 wt%, suitably up to 10 wt%, preferably up to 7.5 wt%, suitably up to 5 wt%, more preferably up to 3 wt%, for example at leaset 2.75 wt% or at least 2.5 wt%.

Each of component (a), component (b), component (c) and component (d) may be present as a mixture of compounds. In such embodiments the above amounts refer to the total of all such compounds present in the composition. The skilled person will appreciate that commercially available sources of surfactants often include significant levels of impurities. The levels of impurity present in commercial surfactants may be up to 25% or even 30% by weight and these impurities usually contain unreacted starting materials and/or byproducts. In addition commercial sources may include diluents or carriers.

For the avoidance of doubt, unless otherwise stated, any definitions of amounts of surfactant stated herein and molar and weight ratios thereof refer to the actual amount of active surfactant compound present in the composition. Each of components (a), (b), (c) and (d) may comprise a mixture of the specified surfactants and any amount mentioned in this specification refers to the total amount of each such surfactant type present in the composition. As will be readily understood by the skilled person, commercial sources of surfactant often comprise mixtures of active surfactant compounds (as well as impurities), for example different isomers, especially if they have been prepared from natural sources, for example fatty acid mixtures found in nature.

The composition of the present invention comprises a first anionic surfactant (a) and optionally a further anionic surfactant (d). The composition may include one or more further anionic surfactants, in addition to component (a) and component (d). Preferably component (a) comprises at least 10 wt% of all anionic surfactants present in the composition, more preferably at least 20 wt%, preferably at least 30 wt%, for example at least 40 wt%.

In some embodiments at least 10 wt% of all anionic surfactants present in the composition comprise a compound of formula (I) in which one of R², R³, R⁴ and R⁵ is Ci to C₄ alkyl, especially methyl and the others are hydrogen, preferably at least 20 wt%, more preferably at least 30 wt%, suitably at least 40 wt%.

In some embodiments at least 10 wt% of all anionic surfactants present in the composition comprise an alkyl ether sulfate compound, preferably at least 20 wt%, more preferably at least 30 wt%, suitably at least 40 wt%.

In some embodiments at least 10 wt% of all anionic surfactants present in the composition comprise an alkyl sulfate compound, preferably at least 20 wt%, more preferably at least 30 wt%, suitably at least 40 wt%.

The compositions of the present invention comprise an amphoteric surfactant including a sugar moiety (b) and may optionally contain another amphoteric surfactant (c). Component (c) is preferably a betaine.

Preferably component (b) comprises at least 10 wt% of all amphoteric surfactants present in the composition, preferably at least 20 wt%, suitably at least 25 wt%, for example at least 30 wt%. In some embodiments it comprises at least 35 wt% or at least 40 wt%. The ratio of the total weight of all anionic surfactants present in the composition to all amphoteric surfactants present in the composition is suitably from 10:1 to 1 :10, preferably from 5:1 to 1 :5, suitably from 3:1 to 1 :3, preferably from 2:1 to 1 :2, more preferably from 1 .5:1 to 1 :1 .5, for example from 1 .25:1 to 1 :1 .25. Preferably the cleansing composition of the present invention comprises less than 3 wt% ethoxylated non-ionic species comprising one or more ethylene oxide residues, preferably less than 1 wt%, more preferably less than 0.5 wt%, preferably less than 0.1 wt%, more preferably less than 0.05 wt%, preferably less 0.01 wt%, preferably less than 0.005 wt% and most preferably less than 0.001 wt%.

In some preferred embodiments the composition of the present invention is substantially free of alkoxylated non-ionic surfactant compounds.

In some preferred embodiments the composition comprises less than 1 wt% ethoxylated compounds of any type, preferably less than 0.1 wt%, more preferably less than 0.001 wt%. Cationic, anionic and amphoteric surfactants including ethylene oxide residues are known. In preferred embodiments the composition of the present invention does not include any of these types of compound. The use of the term "less than" in this specification includes the possibility that there may be none of the stated component.

In one especially preferred embodiment the cleansing composition of the present invention comprises:

(a) from 0.1 to 10wt% of an anionic surfactant;

(b) from 0.1 to 10wt% of an alkyl polyglycoside including at least one betaine moiety;

(c) from 0.1 to 10wt% of an additional betaine surfactant;

(d) from 0.1 to 10wt% of an additional anionic surfactant; and (e) less than 0.1 wt% alkoxylated non-ionic surfactant compounds.

In one especially preferred embodiment the cleansing composition of the present invention comprises: (a) from 1 to 4wt% of an anionic surfactant selected from sodium lauroyl methyl isethionate, sodium cocoyi methyl isethionate, sodium lauryl sulfate, sodium lauryl ether sulfate or a mixture thereof;

(b) from 0.5 to 5wt% of an alkyl polyglycoside including at least one betaine moiety;

(c) from 0.5 to 5wt% of an additional betaine surfactant;

(d) from 0.5 to 5wt% of a taurate surfactant, preferably sodium methyl oleoyl taurate; and (e) less than 0.1 wt% alkoxylated non-ionic surfactant compounds.

The composition of the present invention may comprise one or more further components selected from antibacterial agents, foam boosters, pearlescers, perfumes, dyes, colouring agents, preservatives, thickeners, proteins, polymers such as silicone polymers, phosphate esters, sunscreens, antidandruff agents, buffering agents, moisturisers such as fatty acid alkanolamides, silicone derivatives, cationic polymers, propylene glycol, glycerine, viscosity controlling agents such as methyl cellulose, and other additives which are usually used for cleansers. Suitable conditioning agents include quaternary ammonium compounds of formula

R¹

I

R²— N⁺— R³ X^"

I

R⁴ wherein each of R¹ , R², R³ and R⁴ is an alkyl or alkenyl group and X is chloride, bromide or methyl sulfate. At least one of R¹ , R², R³ and R⁴ is a C₆ to C₂4 alkyl or alkenyl group and the others are to C₄ alkyl, for example methyl. In some embodiments two, three or four of the groups R¹ , R², R³ and R⁴ may be C₆ to C₂₄ alkyl or alkenyl. Suitable conditioning agents for use herein include those designated as polyquaterniums on the INCI list, for example polyquaternium-10 and polyquaternuim-7; as well as guar hydroxypropyl ammonium chloride and similar cationic polymers.

Suitable preservatives include dimethyl dimethylolhydantoin (DMDMH), DMDMH/iodopropynyl- butyl carbamate (Glydant Plus, a registered trademark of Lonza Inc.), benzyl alcohol, methyl paraben, propyl paraben and imidazolidinyl urea. Of course there are many additional preservatives that will function effectively in cleansing compositions, as will be known to the person skilled in the art. The composition of the present invention may comprise a chelating agent. This may be present in an amount of from 0.0001 to 1 wt%, preferably 0.01 to 0.2 wt%. Preferred chelating agents are biodegradable chelating agents. One especially preferred chelating agent is ethylene diaminedisuccinic acid or a salt thereof. Suitably the cleansing composition of the present invention has a pH of from 4 to 8, preferably from 5 to 7, for example from 5.5 to 6.5. The pH can be adjusted, as needed, with either a base, for example sodium hydroxide or sodium carbonate, or an acid for example citric acid, succinic acid, or phosphoric acid. Citric acid is an especially preferred pH adjusting agent. The inventors have surprisingly found that the viscosity of the composition of the present invention may be pH dependent. The viscosity of the composition may increase as the pH decreases. As illustrated in the examples compositions of the invention may have a viscosity at 25 °C in the region of 100 to 400 mPas at pH 7 and a viscosity in the region of 6000 to 8000 mPas at pH 5. The desired viscosity of the composition of the present invention may depend on the desired end use of the composition. For example it has been noted that consumers often prefer baby shampoos to be of lower viscosity but for adult shampoos to be of higher viscosity; and a mild facial wash may suitably have a lower viscosity than an intensive conditioning composition.

Compositions of the present invention may have any viscosity suitable for the intended purpose. Typically a viscosity at 25°C in the range 50 to 20000 mPas is used. In some preferred embodiments the viscosity of the composition of the first aspect at 25 °C varies by more than 1 000 mPas over the pH range 5 to 7, preferably by more than 2000 mPas, more preferably by more than 4000 mPas.

In some preferred embodiments the viscosity of the composition of the first aspect at 25 °C varies by more than 1000 mPas over the pH range 5.5 to 6.5, preferably by more than 2000 mPas, more preferably by more than 3000 mPas.

It is highly advantageous that small changes in pH can provide a significant change in viscosity and this feature can be used to modify the viscosity of the composition. However traditional viscosity modifying agents may also be included.

The composition of the present invention is preferably an aqueous composition. In some embodiments the composition may comprise one or more further solvents in addition to water. Such suitable co-solvents may include polar compounds for example alcohols, glycols and the like.

However in preferred embodiments water is the major solvent present in the composition of the present invention and suitably comprises at least 80 wt% of all solvents present, preferably at least 90 wt%, more preferably at 95 wt%.

The present invention provides a low irritancy cleansing composition. Preferably the composition of the present invention is very low irritating to both the skin and the eyes.

The cleansing composition may be used for any purpose in which low irritancy to the skin and/or eyes is desirable. For example the composition may be used as a facial wash or a product for people with sensitive skin. Most preferably the composition of the present invention is a baby care product, for example a baby bath product or a baby shampoo. Suitably the cleansing composition of the present invention is sufficiently non-irritating to enable it to be used as a baby shampoo.

In particular it is desired that the composition of the present invention exhibits very low ocular irritation.

Ocular irritation can be measured by any suitable method and such methods will be known to the person skilled in the art. A standard method known since 1 944 is the Draize Eye Irritancy Test. This is a long established test which involves delivery of a material into the conjunctival sac of one eye of a rabbit. However this test is now used less often as it is often considered cruel and alternative in vitro tests have been developed. One suitable method is the "EpiOcular" (RTM) of MatTek. This corneal model consists of normal, human-derived epidermal keatinocytes which have been cultured to form a stratified, squamous epithelium similar to that found in the cornea. The epidermal cells, which are cultured on specially prepared cell culture inserts using serum free medium, differentiate to form a multilayered structure which closely parallels the corneal epithelium. The system is said to provide a predictive, morphologically relevant in vitro means to assess ocular irritancy. The results from the EpiOculuar (RTM) test allow a composition to be classified as highly irritating, irritating, mildly irritating or minimally or non-irritating, using the following categories.

. Suitably the low irritancy cleansing formulation of the present invention would be classified as mildly irritating or minimally or non-irritating. Preferably it would be classified as non-irritating or minimally irritating.

Details of the EpiOcular (RTM) test can be found in the paper entitled "Evaluation of the EpiOcular™ Tissue Model as an Alternative to the Draize Eye Irritation Test"; M. Stern, M. Klausner, R. Alvarado, K. Renskers, M. Dickens; Toxicology in Vitro, Volume 12, Issue 4, August 1998, Pages 455-461.

As mentioned above there are a number of eye irritancy tests available. Many of these tests allow the results to be correlated to provide an equivalent score on the Draize test. In order to allow a correlation to be made it is often necessary to carefully select appropriate conditions, especially concentration. However the performance of such a test would be well with the competence of the skilled person.

The composition of the present invention would preferably be such that when testing using in vitro tests of this type it would provide a score equivalent to mild or non-irritating or minimally irritating on the Draize Test, preferably as non-irritating or minimally irritating.

Preferably the cleansing composition of the present invention has low skin irritancy. Skin irritancy may be measured by any suitable means. In one common method a composition is applied to the skin for 14 consecutive days and the irritation evaluated in what is referred to as a 14-Day Cumulative Irritation Test.

There are a number of other ways in which the irritancy of a composition to the skin and/or eyes may be assessed. Some of these are described in the examples.

In addition to providing low irritancy to the eyes and the skin the compositions of the present invention have also been found to be highly effective at cleansing the hair and/or skin and have been found to have good foaming properties.

The compositions of the present invention may thus be regarded as high-foaming compositions. High foaming compositions may be advantageous as they have improved consumer appeal. There are a number of methods by which the foaming properties of a composition may be measured. One such method is detailed in example 2.

The low irritancy cleansing composition of the present invention is very mild and can thus be used as a baby shampoo, baby bath, mild skin cleanser, facial skin cleanser, sensitive skin cleanser and the like.

The low irritancy cleansing composition of the present invention could also be used in animal care applications, for example as a pet shampoo. According to a second aspect of the present invention there is provided a concentrated surfactant composition which upon dilution forms a low irritancy cleansing composition of the first aspect of the present invention. Suitable concentrated surfactant compositions of the second aspect may have a concentration of from 1 .1 to 20 times the concentration of the composition of the first aspect, suitably from 1 .25 to 15 times, preferably from 1 .5 to 10 times, more preferably from 1 .75 to 5 times, for example from 2 to 3 times the concentration of the composition of the first aspect.

Other preferred features of the second aspect are as defined in relation to the first aspect.

The compositions of the first and second aspects of the present invention have been found to have good storage stability. By this we mean that the compositions do not significantly separate or lose activity on storage.

Suitably the compositions of the first and second aspects of the present invention are stable on storing at temperatures of up to 45 °C, for example between 25 °C and 45 °C for periods of up to 1 week, suitably at least 1 month, for example at least 1 year.

Suitably the compositions of the first and second aspects of the present invention are stable during freeze thaw cycles.

According to a third aspect of the present invention there is provided a method of cleansing the skin and/or hair, the method comprising contacting the skin and/or hair with a composition of the first aspect; and rinsing with water.

Preferred features of the third aspect are as defined in relation to the first and second aspects. The invention will now be further described by reference to the following non-limiting examples.

Example 1 Cleansing compositions were prepared comprising the following components:

Composition A Composition B

(comparative) (invention) wt% active wt% active

Sodium lauroyl methyl 3 3

isethionate

Cocamidopropyl betaine 5 2.5

Sugar-containing betaine 2.5

Sodium methyl oleoyl taurate 2 2 Na₃EDDS 0.08 0.08

Citric acid to pH 6 To pH 6

Deionised water to 100% to 100%

Sodium lauroyl methyl isethionate was supplied as Iselux (RTM) flake, a commercially available material comprising 83wt% active ingredient. Cocamidopropyl betaine was provided in a composition comprising 30wt% active ingredient.

The sugar containing betaine used was a commercially available material sold under the trade mark SugaBetaine L and comprising 31 .5wt% active material. This is available from Colonial Chemical and is believed to have the structure shown in figure (VII).

Sodium methyl oleoyl taurate was provided as pureact MS, a commercially available material comprising 32.8wt% active ingredient.

Na₃EDDS was provided as Natrlquest E30 (RTM), a composition comprising 30wt% of the trisodium salt of ethylene diamine disuccinic acid.

Compositions A and B were each tested in a Human Occular Irritation Trial.

The purpose of the trial was to evaluate and compare the potential of the compositions A and B to produce discomfort (stinging, lacrimation and/or irritation) compared to a standard 'no- tear' shampoo, when instilled into the human eye. The standard 'no-tear' shampoo selected was Johnson's ® Baby Shampoo Lot# 0078T. This may be referred to as the control material. Compositions A and B were the test materials. Twelve subjects completed the trial.

The subjects had a cleansed face free of any type of eye care/eye cosmetic product. False eyelashes and/or contact lenses were not worn. Aseptic technique was observed in the preparation and the handling of the test and stardard control methods. Dilutions of the test and standard control materials were prepared as ten percent (1 0%) dilutions, using USP sterile distilled water as the diluent. Just prior to the start of the test, the test material and the control product dilutions were placed in a water bath and brought to a temperature of 35 - 36°C before instillation. The diluted test material and diluted standard control were maintained at this temperature during all phases of the trial. One drop of the diluted test material was instilled into the inferior fornix of the appropriate eye by a registered nurse, using a sterile, 1 cc tuberculin syringe. One drop of the diluted standard control was instilled into the contralateral eye in the same manner. Instillation of test material and control product was randomized for the right and left eye.

Each subject kept their eyes closed for 30 seconds.

Occular evaluations for stinging, lacrimation, bulbar and palpebral conjunctival irritation and dilation of scleral vessels were conducted at the following intervals post-instillation:

30 seconds

5 minutes

15 minutes

30 minutes (subject dismissed, if all symptoms considered normal) 1 hour (optional, if symptoms present at 30 minutes)

Stinging was scored based upon verbal responses from the subjects. Lacrimation and irritation was scored by a Board-Certified Ophthalmologist based upon visual observations using the following scale:

Bulbar Conjunctiva

0 = None

1 = Mildly pink

2 = Moderately pink, some dilation

3 = Intense red vessels, dilated

Palpebral Conjunctiva

0 = None

1 = Mildly pink

2 = Moderately pink

3 = Cherry to deep red

Scleral Vessels

0 = None

1 = Slight dilation

2 = Moderate dilation

3 = Intense dilation

Lacrimation 0 = None

1 = Excessive wetness (no distinct tears)

2 = A few formed tears (contained in orbit)

3 = Intense tearing (leaving orbit)

Eye sting

0 = None

1 = Mild

2 = Moderate

3 = Severe

Table 1 summarises the bulbar conjunctiva irritation scores assessed by the Board Certified Ophthalmologist. Table 2 summarises the palpebral conjunctiva irritation scores assessed by the Board Certified Ophthalmologist.

Table 3 summarises the scleral vessel scores assessed by the Board Certified Ophthalmologist.

Table 4 summarises the lacrimation scores assessed by the Board Certified Ophthalmologist.

Table 5 summarises the perceived eye discomfort scores (sting/burn/pain) at each post- instillation scoring interval.

Table 1

Period after Composition A Composition B instillation Test Control Test Control

30 sec 2.8 2.3 2.5 2.6

5 min 2.9 2.3 2.4 2.5

15 min 3.0 2.2 2.3 2.2

30 min 2.8 2.1 1 .9 2.1

1 hour 2.2 1 .4 0.5 0.8

Table 2

Period after Composition A Composition B instillation Test Control Test Control

30 sec 2.9 2.8 2.5 2.6 5 min 2.9 2.3 2.6 2.8

15 min 3.0 2.3 2.3 2.3

30 min 2.8 2.1 2.3 2.3

1 hour 2.0 1.6 0.4 0.8

Table 3

Period after Composition A Composition B instillation Test Control Test Control

30 sec 2.8 2.3 1.9 1.9

5 min 2.8 2.3 1.8 1.8

15 min 2.8 1.9 1.2 1.6

30 min 2.6 1.8 1.3 1.3

1 hour 1.3 0.8 0.3 0.2

Table 4

Period after Composition A Composition B instillation Test Control Test Control

30 sec 2.8 2.8 2.8 2.8

5 min 2.3 2.3 1.9 1.9

15 min 2.0 2.0 1.1 1.1

30 min 1.5 1.6 1.0 1.0

1 hour 1.1 1.1 0.1 0.1

Table 5

Period after Composition A Composition B instillation Test Control Test Control

30 sec 2.1 1.2 1.3 1.5

5 min 1.3 0.6 0.3 0.4

15 min 1.0 0.3 0.3 0.2

30 min 0.6 0.2 0.3 0.1

1 hour 0.3 0.1 0.1 0.0

The results in Tables 1 to 5 clearly illustrate that for composition A (comparative) observations were unacceptable for nearly every parameter when compared with the control. For composition B (inventive) no statistical difference was observed for any parameter compared with the control. Example 2

The foaming properties of composition A, composition B and the control composition were tested according to the following procedure.

2.0g (± 0.01 g) of each composition was added to a clean 600 ml beaker. 400g (± 0.1 Og) deionised water was added into the beaker. A magnetic stir bar was added and the mixture stirred on a magnetic stirring plate until completely homogeneous. The temperature of the composition was adjusted to 25 °C (± 0.2 °C).

1 00g (± 0.1 Og) of the solution was poured slowly into a 500 ml graduated cylinder, pouring onto the sides of graduated cylinder so as to minimize any foam . The cylinder was stoppered. The cylinder was held at the waist and then slowly inverted ten times over the shoulder and then back down to the waist with a slow swinging motion. Each cycle represents one inversion. Two samples can be tested at one time (left and right arms). The average maximum foam height in ml for each of the samples is recorded in table 6.

Example 3

A concentrated composition was prepared comprising the following components:

Sodium lauroyl methyl isethionate was supplied as Iselux (RTM) flake, a commercially available material comprising 82.6wt% active ingredient. Cocamidopropyl betaine was provided in a composition comprising 30wt% active ingredient.

Example 4

A series of additional formulations were prepared by diluting Concentrated Composition C with water and additional components

JR-125 is a commercially available conditioning polymer (polyquaternium-10) available from Dow Chemicals.

Example 5

Compositions C, D1 , D2 and D3 were evaluated for stability by storing separate samples at room temperature and 49 °C (120°F) for 1 month. All samples were observed to be stable. Viscosity at the start and end of test are shown below.

Viscosity at 25 °C, No. 5 Spindle at 20rpm, mPas

Initial After 1 month at After 1 month at

Room Temperature 49°C

Composition C 1220 1300 760 Composition D1 4260 4100 4760

Composition D2 3920 3780 5040

Composition D3 4220 4260 4380

Example 6

Compositions C and D1 were evaluated for stability by submitting to 3 freeze thaw cycles. Both samples were found to be stable.

Example 7

The viscosity of compositions D1 and D4 was determined over a range of pH's.

Example 8

Composition D1 was compared to seven commercially available baby shampoo products using the foam test of example 2. In this series of tests, both the flash foam and the foam (immediate foam level observed) after 5 minutes was recorded.

Maximum foam height in ml

Flash Foam After 5

Minutes

Composition D1 450 425

Comparative 1 350 350

Comparative 2 350 350

Comparative 3 375 350

Comparative 4 300 275 Comparative 5 300 275

Comparative 6 275 250

Comparative 7 300 275

Example 9

Compositions were prepared comprising the following components:

Disodium oleamido MIPA sulfosuccinate was provided as Pureact MD-318 a commercially available material comprising approximately 30% active material.

Other components were provided in forms described in Example 1 .

The compositions were tested using the EpiOcular in vitro Draize test described above. The results obtained were as shown below

It will see seen that in Example 9 Composition B fell in the most favourable Draize category, non-irritating or minimally irritating. The comparative composition, Composition E, having cocamidopropyl betaine but no sugar-containing betaine, had an inferior Draize result and did not fall in the most favourable Draize category. Example 10

Compositions were prepared comprising the following components:

Sodium lauryl sulfate was supplied as Calfoam (RTM) SLS-30, a commercially available material comprising 30% active ingredient.

Sodium lauryl ether sulfate 2EO was supplied as Calfoam (RTM) SLES-302, a commercially available material comprising 30% active ingredient.

Other components were provided in forms described in Example 1 .

Compositions F and G were tested using the EpiOculuar (RTM) test and from the results an equivalent Draize score was calculated. For composition E the calculated Draize score was 1 1 .2; for composition F the calculated Draize score was 15.5. Thus, having regard to the Draize categories given above, the compositions were respectively found to be non/minimally irritating, and mild.

Claims

A low irritancy cleansing composition comprising :

(a) one or more anionic surfactants; and

(b) one or more amphoteric surfactants including a sugar moiety.

A composition according to claim 1 wherein component (a) is selected from substituted and unsubstituted acyl isethionate compounds; salts of fatty acids; mono- or dialkyl sulfates; alkyl sulfonates; alkyl aryl sulfonates; primary alkane disulfonates; alkene sulfonates; hydroxyalkane sulfonates; alkyl glyceryl ether sulfonates; alpha- olefinsulfonates; alkyl phosphates; alkyl sulfopolycarboxylic acid esters; alkyl sulfosuccinates; non-acylated alkyl isethionates; fatty acid taurates; acyl taurates; products of condensation of fatty acids with oxy- and aminoalkanesulfonic acids; sulfated derivatives of fatty acids and polyglycols; alkyl and acyl sarcosinates; sulfoacetates; alkyl phosphates; alkyl phosphate esters; acyl lactates; and lipoamino acids.

A composition according to claim 2 wherein component (a) is selected from one or more of substituted or unsubstited acyl isethionate compounds, alkyl ether sulphates, alkyl sulfates, and taurate surfactants.

A composition according to any preceding claim wherein component (a) is selected from alkyl sulfate surfactants and alkyl ether sulfate surfactants.

A composition according to any preceding claim wherein component (b) is an alkyl polyglycoside compound including at least one amphoteric group.

A composition according to any preceding claim wherein component (b) comprises a compound of formula (IV):

(IV) wherein R¹ is a C₄ to C₃₆ substituted or unsubstituted hydrocarbyl group; R² is a moiety including an amphoteric group; each S is a saccharide unit; n is an integer from 0 to 3; each L is a linking group; m is at least 1 ; each T is a terminal group; and each p is 0 or a positive integer, provided at least one p is a positive integer.

A composition according to claim 5 wherein R² is a moiety of formula

R³ X N- Y Z

R⁴ wherein R³ and R⁴ is each independently a Ci to C₃₆ substituted or unsubstituted alkyl or alkynyl group; x is an optionally substituted alkylene or arylene group; Y is an optionally substituted alkylene, alkenylene or arylene group; and Z is COO^" or S0₃ ^~

A composition according to any preceding claim wherein component (b) includes compound of formula (V):

wherein each of R¹ , R², R³, R⁴, R⁵, R⁶, R⁷ and R⁸ is independently selected from hydrogen, a hydrocarbyl group, a moiety including an amphoteric group or a cross-link to another saccharide unit, and n is 0 or a positive integer, provided that the molecule includes at least one hydrocarbyl group and at least amphoteric group.

A composition according to any preceding claim wherein component (b) comprises betaine surfactant.

10. A composition according to claim 9 wherein component (b) comprises an alkyl polyglycoside functionalised with bis hydroxyethylglycinate and cross-linked with -CH₂CH(OH)CH₂-.

1 1 . A composition according to any preceding claim which comprises (c) a further amphoteric surfactant.

12. A composition according to claim 9 wherein component (b) comprises at least 25 wt% of all amphoteric surfactants present in the composition.

13. A composition according to any preceding claim which comprises a further anionic surfactant (d). 14. A composition according to claim 13 wherein the further anionic surfactant (d) is selected from sodium methyl lauryl taurate, sodium methyl cocoyl taurate and sodium oleoyl methyl taurate.

15. A composition according to any preceding claim which comprises:

(a) from 0.1 to 10wt% of an anionic surfactant

(b) from 0.1 to 10wt% of an alkyl polyglycoside including at least one amphoteric group;

(c) from 0.1 to 10wt% of an additional amphoteric surfactant; from 0.1 to 10wt% of an additional anionic surfactant; and less than 0.1 wt% alkoxylated non-ionic surfactant compounds.

16. A composition according to any preceding claim which comprises: from 1 to 4wt% of an anionic surfactant selected from sodium lauroyl methyl isethionate, sodium cocoyl methyl isethionate, sodium lauryl sulfate, sodium lauryl ether sulfate or a mixture thereof; from 0.5 to 5wt% of an alkyl polyglycoside including at least one betaine moiety; (c) from 0.5 to 5wt% of an additional betaine surfactant;

(d) from 0.5 to 5wt% of a taurate surfactant, preferably sodium methyl oleoyl taurate; and

(e) less than 0.1 wt% alkoxylated non-ionic surfactant compounds.

17. A composition according to any preceding claim having a viscosity which is pH dependent.

18. A composition according to any preceding claim which is a high-foaming composition.

19. A concentrated surfactant composition which upon dilution forms a low irritancy cleansing composition of any preceding claim.

20. A composition according to any preceding claim which is stable on storing at temperatures of up to 45 °C for at least 1 month.

21 . A method of cleansing the skin and/or hair, the method comprising contacting the skin and/or hair with a composition as claimed in any of claims 1 to 18 or 20; and rinsing with water.