WO2002049587A1

WO2002049587A1 - Hair treatment composition

Info

Publication number: WO2002049587A1
Application number: PCT/EP2001/013191
Authority: WO
Inventors: Lalitesh Chandra; Janet Chisem
Original assignee: Hindustan Lever Ltd; Unilever NV
Current assignee: Hindustan Unilever Ltd; Unilever NV
Priority date: 2000-12-19
Filing date: 2001-11-13
Publication date: 2002-06-27
Anticipated expiration: 2003-06-19
Also published as: AU2002223679A1

Abstract

A hair treatment composition, preferably a shampoo or conditioner, for relaxing hair comprising, (i) a reducing system comprising a reducing agent, and (ii) a malodour-reducing system comprising (a) a first liquid deodorising agent, and (b) a second deodorising agent.

Description

HAIR TREATMENT COMPOSITION

FIELD OF THE INVENTION

This invention relates to hair treatment compositions containing a reducing agent capable of reducing disulphide bonds in the hair.

BACKGROUND OF THE INVENTION

It is well-known that the configuration of hair can be permanently altered by subjecting the hair to treatment with a composition containing a reducing agent which relaxes the hair by disrupting the disulphide bonds in hair proteins, e.g. in keratin. The hair can then be set in the desired configuration by subsequent treatment with a fixing agent, i.e. neutralising or oxidising agent, to recreate the disulphide bonds. In this way, curls or waves can be imparted to straight hair, and, vice versa, curly or wavy hair can be straightened or partially straightened.

Numerous reducing agents have been proposed and used in the permanent waving and straightening of hair. By far the most common are sulphur-based. Well-known sulphur reducing agents include, for example, sulphides, sulphites, bisulphites and thiols. Examples of hair treatment compositions containing sulphur reducing agents for relaxing hair are found in US 3,912,808 (Gillette), US 5,338,540 (Conopco) , EP-A-395,332 (Unilever) and US 4,038,995 (Helene Curtis) .

Other non-sulphur containing reagents have been also been used, including hydroxide, water (steam) , a phosphine, borohydride (MBH₄) , cyanide and amines. Further details of these systems can be found in "Chemical and Physical

Behaviour of Human Hair", CR. Robbins, Springer-Verlag, 3

Ed, ppl06-110. Hydroxides such as sodium hydroxide relax the hair by converting one-third of the cystine contents of hair to lanthionine, along with minor hydrolysis of peptide bonds .

Although most reducing agents do not in themselves have an unpleasant odour, they often generate a variety of malodourous compounds, such as hydrogen sulphide and low molecular weight thiols, which have a particularly unpleasant smell . These malodourous sulphur compounds are thought to be the result of decomposition, in particular oxidation, of the reducing agents and also the presence of impurities. Consequently, many hair treatment compositions, which contain for example a sulphur reducing agent, possess an unpleasant smell.

An additional and generally worse problem is the malodour generated during use, as the reducing agent is oxidised. The malodour often rises to levels, which can be offensive and even nauseous to the user.

Various attempts have been made to reduce the level of malodour to more acceptable levels. For example, attempts have been made to mask the odour using perfumes. However, the odour, especially that generated on use of the product, is generally too powerful to be masked effectively. Alternatively, non-perfume agents who specifically act to reduce malodour have been used. For example, WO 98/38975 (Quest) discloses how incorporating zinc compounds, particularly zinc oxide, in hair treatment compositions containing sulphur reducing agents, substantially reduces malodour production, both on storage and in use. This is said to be applicable to a range of hair treatment compositions containing sulphur reducing agents, but particularly thiol compounds such as thioglycolates . The zinc oxide is said to reduce the production of methanethiol , identified as the primary cause of the in-use malodour associated with thioglycolate-based products. WO91/02538 discloses the use of a reactive zinc salt in formulations containing thiols to prevent formatipn of malodours in skin care compositions.

The present inventors have found that the zinc compounds of

WO 98/38975 do not in themselves give an acceptable reduction of malodour when used in conjunction with a sulphur reducing agent, and more especially when used in conjunction with a sulphite and/or bisulphite reducing system.

Surprisingly, the present inventors have found that the level of malodour generated when using a hair relaxing treatment composition containing a sulphur reducing agent can be significantly reduced by using a combination of malodour-reducing agents. DEFINITION OF THE INVENTION

In a first aspect, this invention provides a hair treatment composition for relaxing hair comprising, (i) a reducing system comprising a reducing agent, and (ii) a malodour-reducing system comprising

(a) a first liquid deodorising agent, and

(b) a second deodorising agent.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

As used herein, the term "deodorising agent" is taken to mean an agent which is not a perfume and which is capable of reducing the level of malodour produced by a reducing agent employed in a hair relaxing treatment composition.

As used herein, the term "solid deodorising agent" is taken to mean a deodorising agent which exists as a solid material at ambient temperature and pressure.

As used herein, the terra "liquid deodorising agent" is taken to mean a deodorising agent which exists as a liquid, viscous-liquid, oil or wax at ambient temperatures and pressures. This definition is meant to exclude solid deodorising agents which have been dissolved into some liquid. Rather, the deodorising agent itself is a liquid, viscous-liquid, oil or wax, in isolation from the composition. Reducing system

The hair treatment composition contains a reducing system comprising a reducing agent which is capable of breaking disulphide bonds in the hair.

In a preferred embodiment, the reducing agent is a sulphur reducing agent .

Suitable sulphur reducing agents, to which the this invention is applicable, include, for example, sulphites, bisulphites, thiols and mercaptans .

Examples of suitable thiol and mercaptan compounds include thioglycolic acid, thiolactic acid, cysteine, cysteamine, alkyl or acyl cysteamines, 3-mercaptoproprionic acid and mercaptocarboxylic acid and the salts thereof, e.g. ammonium salts .

Examples of suitable bisulphite salts are ammonium bisulphite (NH₄HSO₃) , sodium bisulphite (NaHS0₃) , sodium metabisulphite (Na₂S₂θs) , potassium metabisulphite (K₂S₂O₅) , potassium bisulphite ( HSO₃) . Examples of suitable sulphite salts include ammonium sulphite ((NH.j)₂ SO₃) , sodium sulphite ( a₂Sθ₃) and potassium sulphite (K₂SO₃) .

Mixtures of sulphur reducing agents can be used. For example, mixtures of bisulphite salts or sulphite salts may be used, or mixtures of one or more bisulphites and one or more sulphites may be used. A preferred mixture is a bisulphite salt together with a sulphite salt .

In a preferred embodiment, the sulphur reducing agent is a sulphite and/or bisulphite salt (e.g. ammonium or alkali metal, such as sodium, salts) .

Other non-sulphur reducing agents may be used in addition to or in place of the sulphur reducing agent. For example, sodium hydroxide can be used in so-called "lye relaxers" and guanidine hydroxide can be in so-called "non-lye relaxers" .

The total amount of reducing agent or agents present in the hair treatment composition of the invention is in the range of from 0.1 to 20%, preferably from 0.5 to 15%, more preferably from 1.0 to 10%, and most preferably from 2 to 8% by weight based on total weight of the composition.

Other components may be present in the reducing system which act in association with the reducing agent in the relaxation of the hair. These are well-known to the skilled person, and include, for example, pH adjusters. In a preferred aspect of the invention, the pH is less than 9, more preferably less than 8 and most preferably 7.5 or less. This is thought to improve the activity of the reducing system.

Malodour-reducing system

The compositions of invention contain a malodour-reducing system comprising a first deodorising agent which is a liquid and a second deodorising agent which is a solid or a liquid.

The solid and liquid deodorising agents are not perfumes and are capable of reducing the level of malodour produced by a sulphur reducing agent employed in the hair relaxing treatment compositions of the invention.

Liquid deodorising agents

Suitable liquid deodorising agents for use in the present invention include, for example, zinc ricinoleate, undecylenic acid and undecylenic acid derivatives. Undecylenic acid and suitable undecylenic acid derivatives are described in WO 00/51560 (Shaw Mudge & Co.), and include, for example, the product sold under the name Odor Synthesis (ex Shaw Mudge) . Other suitable liquid deodorising agents will be apparent to the skilled person.

Liquid deodorising agent is incorporated into the hair treatment composition in a liquid, viscous-liquid, oily or waxy form. Of course, it will be understood that the liquid deodorising agent does not have to be maintained in the composition in the same form in which it is incorporated.

Liquid deodorising agent can be added at any point during the manufacture of the hair treatment composition, so long as it is suitably mixed into the composition. Preferably, it is substantially uniformly dispersed in the composition. If the liquid deodorising agent is a viscous-liquid, oil or wax, either the deodorising agent and/or the composition may be heated before or during incorporation of the deodorising agent to ensure efficient mixing and dispersion of the deodorising agent. Of course, heating may also take place if the liquid deodorising agent is a liquid.

Solid deodorising agent

Suitable solid deodorising agents for use in the present invention include, for example, the zinc compounds described in WO 98/38975 (i.e. salts such as zinc carboxylate, zinc acetate, zinc chloride, and zinc oxide) , aluminosilicates (e.g. montmorillonites) , zeolites, magnesium oxide, alumina and layered double hydroxides (e.g. hydrotalcites) . Other suitable solid deodorising agents include silicas (e.g. amorphous silicas, silicone dioxide, synthetic silicas), silicates (e.g. alkali metal silicates, alkaline earth metal silicates, transition metal silicates and synthetic silicates), and carbonates (e.g. alkali metal carbonates, alkaline earth metal carbonates, transition metal carbonates and synthetic carbonates) .

Preferred solid deodorising agents are transition metal oxides (e.g. zinc and magnesium oxides), aluminosilicates, silicas and layered double hydroxides (LDH) .

In a preferred embodiment, the solid deodorising agent is only sparingly water-soluble or water-insoluble.

In another preferred embodiment, the solid deodorising agent is an inorganic compound. In a further preferred embodiment, the solid deodorising agent is a zinc compound, preferably zinc oxide.

The solid deodorising agent is incorporated into hair treatment composition in a solid form. Preferably, the solid deodorising agent is maintained in a solid form upon incorporation, i.e. it is only sparingly-soluble or insoluble in the hair treatment composition of which it forms a component .

In a preferred aspect of the invention, the pH of the composition is selected in order to reduce the solubility of the solid deodorising agent. When the deodorising agent is a zinc compound such as zinc oxide, a pH for the composition of 6.5 or greater is preferred, more preferably 7 or greater. Any of these preferred lower pH levels can be combined with any of the preferred upper pH levels specified to improve the activity of the reducing system in order to provide preferred ranges of pH for the compositions.

Typically, the solid deodorising agent is incorporated into the hair treatment composition as a particulate material, typically a powder. The solid deodorising agent can be added at any point during the manufacture of the hair treatment composition, so long as it is suitably mixed into the composition. Preferably, it is substantially uniformly dispersed in the composition. Liquid/solid deodorising agent combination

In compositions containing a combination of liquid and solid deodorising agents, the first liquid deodorising agentis suitably present in an amount of from 0.01 to 10%, preferably 0.05 to 10, more preferably 0.1 to 4%, most preferably 0.1 to 2.0% by weight based on total weight of the composition, and, the second solid deodorising agent is suitably present in an amount of from 0.05 to 15%, preferably 0.1 to 10%, more preferably 0.5 to 7%, most preferably 0.5 to 5%, typically about 4% by weight based on total weight of the composition.

Suitably, the weight ratio of first liquid to second solid deodorising agent in the composition is in the range from 20:1 to 1:20, preferably from 10:1 to 1:10, more preferably from 5:1 to 1:5. A particularly preferred range is from 1:2 to 1:5, for example 1:4.

In a preferred embodiment, the first liquid deodorising agent is zinc ricinoleate.

Liquid/liquid deodorising agent combination

When the second deodorising agent is a liquid, then the first and second deodorising agents must be different.

In addition, when the second deodorising agent is a liquid, then it is preferred that at least one of the first and second deodorising agents be only sparingly water-soluble or water-insoluble .

Preferably, one of the deodorising agents is only sparingly water-soluble or water-insoluble and the other is substantially soluble.

In compositions containing a combination of liquid deodorising agents, the first and second deodorising agents are each suitably present in an amount of from 0.01 to 5, preferably 0.05 to 5, more preferably 0.1 to 2%, most preferably 0.1 to 1.0% by weight based on total weight of the composition.

Suitably, the weight ratio of the first and second liquid deodorising agents in the composition is in the range from 20:1 to 1:20, preferably from 10:1 to 1:10, more preferably from 5:1 to 1:5, most preferably from 2:1 to 1:2, for example 1:1.

Preferably, the sparingly water-soluble or water-insoluble liquid deodorising agent comprises a hydrophobic portion, preferably an alkyl or alkenyl carbon chain. Preferably, it is an oil or wax.

In a preferred embodiment, at least one of the liquid deodorising agents is zinc ricinoleate. Product Form

Hair treatment compositions of the invention may suitably take the form of shampoos, conditioners, sprays, mousses, gels, cremes, lotions, oils, waxes or a chemical treatment.

Preferably the hair treatment compositions comprise an aqueous medium.

The compositions are preferably in the form of a shampoo/conditioner, rinse-off or leave-on conditioner, or styling spray.

It is not essential to use a fixing agent, i.e. a neutralising or oxidising agent, in a second step following treatment with the hair treatment compositions of this invention. In a preferred embodiment, a "single" step treatment is employed in which the disulphide bonds reform partially during rinsing and partially during natural exposure of the hair to air post-treatment.

Shampoo/conditioner

Shampoo compositions according to the invention will comprise one or more cleansing surfactants which are cosmetically acceptable and suitable for topical application to the hair. Further surfactants may be present as an additional ingredient as emulsifying agent for oily or hydrophobic components (such as silicones) which may be present in the shampoo . It is preferred that shampoo compositions of the invention comprise at least one further surfactant (in addition to that which may be used as emulsifying agent) to provide a cleansing benefit.

Suitable cleansing surfactants, which may be used singularly or in combination, are selected from anionic, amphoteric and zwitterionic surfactants, cationic surfactants, and mixtures thereof. The cleansing surfactant may be the same surfactant as the emulsifier, or may be different. Preferred cleansing surfactants are selected from anionic, amphoteric and zwitterionic surfactants, and mixtures thereof.

Examples of anionic surfactants are the alkyl sulphates, alkyl ether sulphates, alkaryl sulphonates, alkanoyl isethionates, alkyl succinates, alkyl sulphosuccinates, N- alkyl sarcosinates, alkyl phosphates, alkyl ether phosphates, alkyl ether carboxylates, and alpha-olefin sulphonates, especially their sodium, magnesium, ammonium and mono-, di- and triethanolamine salts. The alkyl and acyl groups generally contain from 8 to 18 carbon atoms and may be unsaturated. The alkyl ether sulphates, alkyl ether phosphates and alkyl ether carboxylates may contain from 1 to 10 ethylene oxide or propylene oxide units per molecule.

Typical anionic surfactants for use in shampoos of the invention include sodium oleyl succinate, ammonium lauryl sulphosuccinate, ammonium lauryl sulphate, sodium dodecylbenzene sulphonate, triethanolamine dodecylbenzene sulphonate, sodium cocoyl isethionate, sodium lauryl isethionate and sodium N-lauryl sarcosinate. The most preferred anionic surfactants are sodium lauryl sulphate, triethanolamine monolauryl phosphate, sodium lauryl ether sulphate 1 EO, 2EO and 3EO, ammonium lauryl sulphate and ammonium lauryl ether sulphate 1EO, 2EO and 3EO. Examples of amphoteric and zwitterionic surfactants include alkyl amine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sulphobetaines (sultaines) , alkyl glycinates, alkyl carboxyglycinates, alkyl amphopropionates , alkylamphoglycinates, alkyl amidopropyl hydroxysultaines, acyl taurates and acyl glutamates, wherein the alkyl and acyl groups have from 8 to 19 carbon atoms. Typical amphoteric and zwitterionic surfactants for use in shampoos of the invention include lauryl amine oxide, cocodimethyl sulphopropyl betaine and preferably lauryl betaine, cocamidopropyl betaine and sodium cocamphopropionate .

The shampoo composition can also include co-surfactants, to help impart aesthetic, physical or cleansing properties to the composition. A preferred example is a nonionic surfactant, which can be included in an amount ranging from 0% to about 5% by weight based on total weight.

For example, representative nonionic surfactants that can be included in shampoo compositions of the invention include condensation products of aliphatic (C8 - Cis) primary or secondary linear or branched chain alcohols or phenols with alkylene oxides, usually ethylene oxide and generally having from 6 to 30 ethylene oxide groups.

Other representative nonionics include mono- or di-alkyl alkanola ides . Examples include coco mono- or di- ethanolamide and coco mono-isopropanolamide.

Further nonionic surfactants which can be included in shampoo compositions of the invention are the alkyl polyglycosides (APGs) . Typically, the APG is one which comprises an alkyl group connected (optionally via a bridging group) to a block of one or more glycosyl groups. Preferred APGs are defined by the following formula: RO - (G) n

wherein R is a branched or straight chain alkyl group which may be saturated or unsaturated and G is a saccharide group.

R ma -represent a mean alkyl chain length of from about Cs to about C20. Preferably R represents a mean alkyl chain length of from about Cs to about C12. Most preferably the value of R lies between about 9.5 and about 10.5. G may be selected from Cs or Cε monosaccharide residues, and is preferably a glucoside. G may be selected from the group comprising glucose, xylose, lactose, fructose, mannose and derivatives thereof . Preferably G is glucose .

The degree of polymerisation, n, may have a value of from about 1 to about 10 or more. Preferably, the value of n lies in the range of from about 1.1 to about 2. Most preferably the value of n lies in the range of from about 1.3 to about 1.5.

Suitable alkyl polyglycosides for use in the invention are commercially available and include for example those materials identified as: Oramix NS10 ex Seppic; Plantaren 1200 and Plantaren 2000 ex Henkel .

The total amount of surfactant (including any co-surfactant , and/or any emulsifying agent) in shampoo compositions of the invention is generally from 0.1 to 50% by weight, preferably from 5 to 30%, more preferably from 10% to 25% by weight of the total shampoo composition. Rinse-off Conditioners

Rinse-off conditioner compositions of the invention preferably comprise one or more conditioning surfactants which are cosmetically acceptable and suitable for topical application to the hair.

Suitable conditioning surfactants are selected from cationic surfactants, used singly or in admixture.

Cationic surfactants useful in compositions of the invention contain amino or quaternary ammonium hydrophilic moieties which are positively charged when dissolved in the aqueous composition of the present invention.

Examples of suitable cationic surfactants are those corresponding to the general formula:

[N(Rι) (R₂) (R₃) (R₄)]⁺ (X)

in which Ri, R₂, R₃, and R₄ are independently selected from

(a) an aliphatic group of from 1 to 22 carbon atoms, or (b) an aromatic, alkoxy, polyoxyalkylene, alkylamido, hydroxyalkyl, aryl or alkylaryl group having up to 22 carbon atoms; and X is a salt-forming anion such as those selected from halogen, (e.g. chloride, bromide), acetate, citrate, lactate, glycolate, phosphate nitrate, sulphate, and alkylsulphate radicals. The aliphatic groups can contain, in addition to carbon and hydrogen atoms, ether linkages, and other groups such as amino groups. The longer chain aliphatic groups, e.g., those of about 12 carbons, or higher, can be saturated or unsaturated.

Preferred are cationic surfactants containing two long alkyl chains and two short alkyl chains or especially those containing one long alkyl chain and three short alkyl chains . The long alkyl chains in such compounds generally have from 12 to 22 carbon atoms, preferably from 16 to 22 carbon atoms, and the corresponding short alkyl chains generally have from 1 to 3 carbon atoms, preferably from 1 to 2 carbon atoms.

The most preferred cationic surfactants for compositions of the present invention are those selected from cetyl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride, behenyl trimethyl ammonium chloride, and mixtures thereof.

Further examples of suitable cationic surfactants include the materials having the following CTFA designations: Quaternium- 5, Quaternium-8, Quaternium-18, Quaternium-24, Quaternium-26, Quaternium-27, Quaternium-30, Quaternium-31, Quaternium-33 , Quaternium-43, Quaternium-52 , Quaternium-53 , Quaternium-56, Quaternium-60, Quaternium-62 , Quaternium-70, Quaternium-72 , Quaternium-75, Quaternium-77, Quaternium-78 , Quaternium-79, Quaternium-80, Quaternium-81, Quaternium-82, Quaternium-83 , Quaternium-84, and mixtures thereof.

Salts of primary, secondary and tertiary fatty amines are also suitable cationic surfactants. The alkyl groups of such amines preferably have from 12 to 22 carbon atoms, and can be substituted or unsubstituted.

Preferred are acid-neutralised amidoamine compounds, wherein the amidoamine compound has the general formula:

R₅ - C (O) - NH - R₆ - N( R₇) ( R₈)

wherein R₅ is a fatty acid chain containing from 12 to 22 carbon atoms, RQ is an alkylene group containing from one to four carbon atoms, and R₇ and Re are, independently, an alkyl group having from one to four carbon atoms .

Examples of suitable amidoamine compounds of the above general formula include stearamidopropyl dimethylamine, stearamidopropyl diethylamine, stearamidoethyl dimethylamine, stearamidoethyl diethylamine, palmitamidopropyl dimethylamine, behenamidopropyl dimethylamine, myristamidopropyl dimethylamine, oleamidopropyl dimethylamine, ricinoleamidopropyl dimethylamine, and combinations thereof.

The acid used to neutralise the amidoamine compound can be essentially any organic acid or mineral acid of sufficient acid strength to neutralise a free amine nitrogen. Such acids include hydrochloric acid, sulphuric acid, nitric acid, phosphoric acid, lactic acid, citric acid, tartaric acid, acetic acid, gluconic acid, glycolic acid and propionic acid, or combinations thereof. Lactic acid is a preferred neutraliser since it can provide superior composition stability.

Mixtures of any of the foregoing cationic surfactants may also be suitable.

The level of conditioning surfactant is preferably from 0.01 to 10%, more preferably 0.05 to 5%, most preferably 0.1 to 3% by weight based on total weight of the composition.

Rinse-off conditioner compositions of the invention advantageously incorporate a fatty alcohol material .

By "fatty alcohol material" is meant a fatty alcohol, an alkoxylated fatty alcohol, or a mixture thereof.

Representative fatty alcohols comprise from 8 to 22 carbon atoms, more preferably 16 to 20. Examples of suitable fatty alcohols include cetyl alcohol, stearyl alcohol and mixtures thereof. The use of these materials is also advantageous in that they contribute to the overall conditioning properties of compositions of the invention.

Alkoxylated, (e.g. ethoxylated or propoxylated) fatty alcohols having from about 12 to about 18 carbon atoms in the alkyl chain can be used in place of, or in addition to, the fatty alcohols themselves. Suitable examples include ethylene glycol cetyl ether, polyoxyethylene (2) stearyl ether, polyoxyethylene (24) cetyl ether, and mixtures thereof. The level of fatty alcohol material in compositions of the invention is suitably from 0.01 to 15%, preferably from 0.1 to 10% by weight based on total weight of the composition.

The weight ratio of conditioning surfactant to fatty alcohol material is suitably from 10:1 to 1:10, preferably from 4:1 to 1:8, optimally from 1:1 to 1:7.

Leave-on Conditioners

Leave-on conditioner compositions of the invention preferably comprise a nonionic surfactant typically in the range of about 0.01% to about 1% by weight based on total weight of the composition.

For example, representative nonionic surfactants that can be included in shampoo compositions of the invention include condensation products of aliphatic (Cs - Cis) primary or secondary linear or branched chain alcohols or phenols with alkylene oxides, usually ethylene oxide and generally having from 6 to 30 ethylene oxide groups.

Other representative nonionic surfactants include mono- or di-alkyl alkanolamides . Examples include coco mono- or di- ethanolamide and coco mono-isopropanolamide.

Further nonionic surfactants which can be included in shampoo compositions of the invention are the alkyl polyglycosides (APGs) . Typically, the APG is one which comprises an alkyl group connected (optionally via a bridging group) to a block of one or more glycosyl groups . Preferred APGs are defined by the following formula:

RO - (G) n

R may represent a mean alkyl chain length of from about C₅ to about C₂o- Preferably R represents a mean alkyl chain length of from about Cs to about C₁₂ • Most preferably the value of R lies between about 9.5 and about 10.5. G may be selected from C₅ or CQ monosaccharide residues, and is preferably a glucoside. G may be selected from the group comprising glucose, xylose, lactose, fructose, mannose and derivatives thereof. Preferably G is glucose.

Suitable alkyl polyglycosides for use in the invention are commercially available and include for example those materials identified as: Oramix NS10 ex Seppic; Plantaren 1200 and Plantaren 2000 ex Henkel . Other sugar-derived nonionic surfactants which can be used include the Cχo-Ci8 N-alkyl (Ci-Cg) polyhydroxy fatty acid amides, such as the C₁₂-C₁₈ N-methyl glucamides, as described for example in WO 92 06154 and US 5 194 639, and the N-alkoxy polyhydroxy fatty acid amides, such as Cio-Ciβ N-(3- methoxypropy1) glueamide .

Leave-on conditioner compositions of the invention may also comprise, based upon the total weight of the composition, from about 0.01% to about 1.0% of a fatty alcohol material such as those described above in the context of rinse-off conditioner compositions. Exemplary fatty alcohol materials include lauryl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, and mixtures thereof.

Optional Ingredients

Silicones

Compositions according to the invention can optionally include additional conditioning agents for hair such as silicones .

Silicones are particularly preferred conditioning agents for hair. Representative silicones include volatile and nonvolatile silicones, such as for example polyalkylsiloxanes (optionally end-capped with one or more hydroxyl groups) , polyalkylaryl siloxanes, siloxane gums and resins, cyclomethicones, aminofunctional silicones, quaternary silicones and mixtures thereof. Preferred silicones include polydimethylsiloxanes (of CTFA designation dimethicone) , siloxane gums, aminofunctional silicones (of CTFA designation amodimethicone) and hydroxylated polydimethylsiloxanes (of CTFA designation dimethiconol) .

Various methods of making emulsions of particles of silicones are available and are well known and documented in the art .

Suitable silicone emulsions are commercially available in a pre-emulsified form. This is particularly preferred since the pre-formed emulsion can be incorporated into the composition by simple mixing.

Examples of suitable pre-formed emulsions include emulsions DC2-1310, DC2-1865, DC2-1870, DC2-1766 and DC2-1784, available from Dow Corning. These are emulsions of dimethiconol. Siloxane gums are also available in a pre- emulsified form, which is advantageous for ease of formulation. A preferred example is the material available from Dow Corning as DC X2-1787, which is an emulsion of cross-linked dimethiconol gum.

The amount of silicone incorporated into compositions according to the invention depends on the level of conditioning desired and the material used. A preferred amount is from 0.01 to about 10% by weight of the total composition although these limits are not absolute. The lower limit is determined by the minimum level to achieve conditioning and the upper limit by the maximum level to avoid making the hair and/or skin unacceptably greasy. We have found that an amount of silicone of from 0.5 to 1.5% by weight of the total composition, is a particularly suitable level .

Other optional ingredients

Compositions of this invention may contain any other ingredient normally used in hair treatment formulations. These other ingredients may include additional conditioning agents (e.g. oils and blends of oils), viscosity modifiers, preservatives, colouring agents, polyols such as glycerine and polypropylene glycol, chelating agents such as EDTA, antioxidants such as vitamin E acetate, fragrances, antimicrobials and sunscreens. Each of these ingredients will be present in an amount effective to accomplish its purpose. Generally these optional ingredients are included individually at a level of up to about 5% by weight of the total composition.

The invention is further illustrated by way of the following non-limiting Examples, in which all percentages quoted are by weight based on total weight unless otherwise stated.

EXAMPLES

Example 1 ; Sniff Test

The following leave-on base conditioner formulation was prepared:

To the base formulation, the following additional components were added (the level of water being adjusted to compensate) . The resulting compositions assessed in a sniff test and given a malodour score :

Fifteen people were screened for ability to differentiate between slightly different levels of intensity of malodour produced on hair by reaction with bisulphite. Of these, seven were found to be suitable and were used in all further sniff testing.

Spanish, straight, dark brown hair was used in switches of 0.25 g and 2 inches. The conditioner compositions were applied to the hair at a w/w ratio of 1:1 and worked in with the fingers. The test was carried out just after application of the conditioner, when malodour is usually at its worst.

The hair switches were laid out in small tubs, spaced well apart on the bench. Panellists were asked to sniff each hair switch in turn and to assign a malodour score according to the following scale:

1 = no malodour 2 = slight malodour

3 = moderate malodour

4 = strong malodour

5 = very strong malodour

Standards were given for points 1 and 5 on the scale, where 1 is a hair switch with non-bisulphite containing conditioner on it and 5 is a switch with bisulphite conditioner with no malodour active in it . A control switch treated with just base formulation was used to establish the 1 standard. The panellists always started with the lowest intensity of smell (to avoid nasal fatigue) and care was taken when using the "no. 5" standard that nasal fatigue did not set in. Panellists also "cleared" their noses between each sniff by sniffing clean, non-smelling air in through the nose. This also helped eliminate nasal fatigue

The use of 2 wt% zinc oxide (a solid deodorising agent) in comparative composition II and 0.5 wt% zinc ricinoleate (a liquid deodorising agent) in comparative composition III, as expected, gave some improvement in malodour score compared to the negative control Example I. However, composition A containing the combination of 2 wt% zinc oxide and 0.5 wt% zinc ricinoleate gave a improvement in malodour score greater than the combination of the individual scores of compositions II and III.

Example 2 ; Sniff Test The following additional components were added to the base formulation of Example 1 (the level of water being adjusted to compensate) and the resulting compositions assessed in a sniff test for a malodour score as described in Example 1:

The use of 1 wt% Odor Synthesis (a liquid deodorising agent) in comparative composition V and 1 wt% zinc ricinoleate (another liquid deodorising agent) in comparative composition VI gave relatively small improvements in malodour score compared to the negative control composition IV. However, composition C containing the combination of Odor Synthesis and zinc ricinoleate gave a improvement in malodour score significantly greater than the combination of the individual scores of V and VI. This is even more surprising in view of the fact that the amount of each of the deodorising agents in composition C is 50% that present in compositions V and VI.

Example 3 ; Sniff Test

The following additional components were added to the base formulation of Example 1 (the level of water being adjusted to compensate) and the resulting compositions assessed in a sniff test for a malodour score as described in Example 1 :

The use of 2 wt% clay (a solid deodorising agent) in comparative composition VIII gave a small improvement in malodour score compared to the negative control composition IV. The use of 2 wt% zinc oxide (another solid deodorising agent) in comparative composition X gave a reasonable improvement in malodour score compared to the negative control composition IV. However, composition X containing the combination of clay and zinc oxide at the absolute same levels as present in compositions VIII and IX, gave no significant improvement in malodour score over composition IX which merely contains the zinc oxide.

Example 4 : Headspace Analysis

Compositions I, II, III and A as described in Example 1 were tested in a headspace analysis according to the following procedure .

The compositions were applied to the switches of hair and worked in. Excess product was squeezed out and the switches transferred to 20 ml vials and crimp sealed with a PTFE faced septum. The vials were then left at room temperature for 30 minutes. The "headspace" in the vials was sampled using a 75μm Carboxen-PDMS SPME fibre for 10 minutes and the contents of the fibre analysed using gas chromatography (HP G1800 GCD GCMS) . The fibre was desorbed for 1 minute at 240 °C. Analysis was on a 30m x 0.25mm x 0.25μm film HP Innowax column at a flow rate of 1 ml/min, the oven being at 40°C for 1 min and then increasing at a rate of 10°C/min to 230°C. The mass range was 33 to 300 amu.

The results were as follows :

The level of methanediol ions resulting from composition A, containing 2 wt% zinc oxide and 0.5 wt% zinc ricinoleate, is only 8% of that produced by composition I which contains no deodorising agents. In comparison, compositions II and III, which contain 2 wt% zinc oxide and 0.5 wt% zinc ricinoleate, respectively, only gave a reduction in methanediol levels to 72 and 54% of that given by composition I . Clearly, there is a significant synergistic effect obtained by combining the two deodorising agents.

Claims

1. A hair treatment composition for relaxing hair comprising, (i) a reducing system comprising a reducing agent, and (ii) a malodour-reducing system comprising

(a) a first liquid deodorising agent, and

(b) a second deodorising agent.

2. A composition according to claim 1, in which the second deodorising agent is a solid.

3. A composition according to claim 2, in which the solid deodorising agent is only sparingly water-soluble or water-insoluble.

4. A composition according to claim 3, in which the second deodorising agent is a zinc compound, preferably zinc oxide .

5. A composition according to claim 1, in which the second deodorising agent is a liquid.

6. A composition according to any preceding claim 1, in which the first liquid deodorising agent is zinc ricinoleate.

7. A composition according to any preceding claim, in which the reducing agent is a sulphur reducing agent.

8. A composition according to claim 7, in which the sulphur reducing agent is a sulphite and/or bisulphite salt .

9. A composition according to any preceding claims, which is in the form of a rinse-off or leave-on conditioner.