WO2002013773A2

WO2002013773A2 - Cosmetic composition

Info

Publication number: WO2002013773A2
Application number: PCT/EP2001/009078
Authority: WO
Inventors: Janet Chisem; Ezat Khoshdel; Paul Howard Neill; Sagrario Pascual; Euan Stuart Reid
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 2000-08-16
Filing date: 2001-08-06
Publication date: 2002-02-21
Also published as: AR030353A1; AU2001293728A1; WO2002013773A3; GB0020201D0

Abstract

Cosmetic and/or personal care compositions are provided which comprise a coupling agent, one or more compounds capable of forming an amide bond as a result of a reaction involving the coupling agent and a cosmetically acceptable diluent and/or carrier. Compounds which may be used in the compositions include amino acids and coupling agents which may be used for the formation of the amide bond include carbodiimides. The compositions may be packaged in two-part form, with the coupling agent and the one or more compounds capable of forming the amide bond kept separate from each other, and are used for the treatment of hair to improve its body.

Description

COSMETIC COMPOSITION

Field of the Invention

This invention relates to cosmetic and/or personal care compositions, such as for application to hair, and to the use of the compositions in the treatment of hair.

Background and Prior Art

The use of synthetic and natural polymers in hair cosmetic formulations such as hair sprays, -mousses, gels, shampoos and conditioners is commonplace in the modern hair care regime. These products deposit functional polymeric species onto hair which alter surface properties, thus imparting benefits such as conditioning, ease of styling, shine and body. The polymers are generally deposited by adsorption .onto .the surface of the hair and are, therefore, removable by common physical treatments of hair such as brushing or washing. Therefore, the benefits provided by these polymers are only temporary. Whilst in certain cases, for example in styling, this sort of temporary" benefit is the most desirable result, more durable or even permanent effects, such as body and hair fibre strength, are difficult to achieve using these materials .

An alternative approach, which offers greater potential for strengthening or bodifying hair, is the introduction or delivery of functional polymers inside the hair. Since high molecular weight polymers are too large to diffuse into the hair strand, the formation of polymers within the hair via the penetration and subsequent polymerisation of low molecular weight monomers has been proposed. However, with the exception of the oxidative reactions of dyes, such internal polymerisation has been limited to a laboratory curiosity and has had no commercial significance. For example, Wolfram, J Soc Cosmet. Chem, 1969, 20, 539-553, describes the polymerisation of vinyl monomers on and in human hair by free radical polymerisation. This polymerisation involves the use of the toxic and allergenic reagents methacrylamide and potassium persulphate and requires a pre-treatment involving a reducing step. Also, US 4588760 describes the formation of polymers on hair using resorcinol arid a heximinium salt, the latter of which is not desirable 'in a composition for application to human skin or hair, for modifying the moisture retention of hair in ^"order to improve its settability. In view of the toxicity and/or irritancy of the reagents, these systems are not suitable for most commercial applications.

Similarly, US 4338295 teaches hair-setting compositions consisting of an aqueous solution containing a precondensate of glyceraldehyde and resorcinol. Also, GB 1197037 relates to compositions or waving and conditioning human hair containing monohydroxymethylurea and/or monohydroxymethylthiourea and, optionally, an acidic polymerisation catalyst. Fox, Cosmet . Toiletries, 1995, 110 (8) , 19-22 reviews skin and skin care topics and mentions in si tu oligomer polymerisation onto hair.

A method for treating human hair which avoids the use of toxic, hazardous or harmful monomers is described in US 5362486. The method comprises the polymerisation of an oligomer formed by end-capping a urethane oligomer with a bisulphite or an acrylate group. In the unrelated field of the industrial treatment of textile fibres, NL 6614231 describes the treatment of wool fibres with a diamine and a dicarboxylate to improve dyeability and reduce water absorption by the fibres.

GB-A-2125291 describes a hair setting process in which a water soluble polymer containing primary amide groups is cross-linked with a compound such as glutaraldehyde . The process appears to require cross-linking of the amide| groups , rather than the formation of any „ne.w amide groups in the process.

The use of preformed (β-alanine) polymers in cosmetic compositions for treating the hair and the skin is described in GB-A-2104379.

GB 1604471 and GB 1604473 describe compositions for conditioning hair which comprise cationic polymers that have been cross-linked prior to application -to -the hair. There is no teaching in either document of reaction of the polymers on the hair to "farm -an "ami e bond in the presence of a coupling agent.

It is an object of the present invention to reduce and/or alleviate the problems of the prior art .methods described above. Thus, the invention aims to provide systems for treating hair which are less toxic and/or irritant than the compositions of the prior art methods described above. A further object of the invention is the provision of systems for treating hair to increase its compression resistance and/or volume and/or thickness and/or strength, which are superior to the compositions of the prior art. Another object is to increase grip on the brush during brushing (ie, to decrease ease of comb) . It is a further object of the invention to provide systems which may be used to deliver compounds to hair which are of therapeutic benefit to the hair.

Summary of the Invention

According to the present invention, there is provided a cosmetic and/or personal care composition comprising a coupling agent, one or more compounds capable of forming an amide bond as a result of a reaction involving the coupling agent and a cosmetically acceptable diluent and/or carrier.

i |In another aspect, the invention provides a packaged article having separately packaged first and second parts, the first and second parts being capable of being mixed to form a composition of the invention, the first part comprising the coupling agent and the second part comprising the one or more compounds capable of forming an amide bond.

Another aspect of the invention is a method of treating hair which comprises applying to the hair a' "COmposition of the invention.

Also provided by the invention is the use ^' of the compositions of the invention in the cosmetic -and/.or therapeutic treatment of hair. For example, the cosmetic treatment may increase the compression resistance and/or the volume and/or the thickness and/or strength of hair and/or decrease ease of comb. Detailed Description of the Invention

Composition of the Invention

The invention involves cosmetic and/or personal care systems for treating hair.

The compositions of the invention comprise a coupling agent and one or more compounds capable of forming an amide bond as a result of a reaction involving the coupling agent .

The One or More Compounds Capable of Forming an Amide Bond

The one or more compounds capable of forming an amide bond preferably comprise carboxylic acid anό or -amino

(eg, - H₂) groups. The one or more compounds capable of forming an amide bond include single compounds and mixtures of compounds . The compound or compounds may comprise one, two or more than two carboxylic acid groups and/or one, two or more than two amiτio --groups . Suitably, the one or more compounds are selected from mono- and di- carboxylic acids, mono- and di- amines, amino acids and mixtures thereof . The one or more compounds may be derivatised so as to be more reactive towards the formation of amide bonds. For example, a carboxylic acid group may be in the form of an active derivative of the type known in peptide chemistry (eg, as an active ester, an anhydride or a cyclic compound such as a lactam) .

Preferably, the one or more compounds comprise one or more amino acids and, more preferably, comprise at least 90% by weight (such as at least 95% by weight) of one or more amino acids. Amino acids suitable for use in the invention include all compounds containing at least one carboxylic acid (-COOH) group and at least one amino (-NH₂) group. The carboxylic acid and amino groups may be bound to the same carbon atom or to different carbon atoms in the compound. Thus, the amino acids may be, for example, α- or β amino acids. The amino acids may be natural or synthetic and are preferably natural amino acids or derivatives thereof. Suitable derivatives of natural amino acids include, for example, acid and base salts, esters (where the amino acid contains more than one carboxylic acid group) and compounds which contain an additional polar (charged or uncharged) group compared to the corresponding natural amino acid (eg, by sulphonation of an aromatic ring) . Other suitable derivatives include, for example, β- amino acids such as β-alanine.

When the amino acids contain an asymmetric centre, they may be in the form of racemic mixtures or optically active forms containing predominantly one enantiomer (such as up to 100% of one enantiomer) .

Natural amino acids which may be used, in the present invention include the following:

Glycine Alanine

Valine Leucine

Isoleucine Phenylalanine

Proline Tryptophan

Serine Threonine Cysteine Methionine

Aspartic acid Glutamic acid

Asparagine Glutamine

Tyrosine Histidine

Lysine Arginine

Preferably, the amino acids are used in the form of their L- stereoisomers . Amino acids which contain aromatic rings are especially suitable for use in the invention. An example of such an amino acid is tryptophan, preferably L-tryptophan. Other preferred amino acids are arginine and cysteine.

It is desirable, but not essential, that the amino acids are soluble in water, an alcohol (including mono- , di-, tri- and poly- hydric alcohols), an ether (eg, low molecular weight polyethylene glycols or polypropylene glycols, diglyme and glycerol ..ethers)-, esters (eg, esters of glycerol) and mixtures thereof. Alcohols include, but are not limited to, methanol, ethanol, 1-propanol, 2-propanol and 1-butanol, preferably ethanol and 2-propanol.

When the one or more compounds capable of forming .an amide bond are one or more amino acids (ie, one amino acid or a mixture of amino acids) , they may react to form an oligomer or a polymer on and/or in the hair fibres. If a single amino acid is used, the polymer may be a homopolymer. If more than one ami.no-a.cid is used, the polymer will be a copolymer (such as a block or random copolymer) , typically a random copolymer.

Certain amino acids which contain more than one carboxylic acid or amino group may be useful either alone or together with one or more other amino acids to form a polymer which has a degree of cross-linking. For example, aspartic acid (which has two carboxylic acid groups) may be used for this purpose.

After the reaction to form the amide bonds, the product of the reaction of the amino acids (eg, polymer or oligomer) may be physically attached to the outside of the hair fibres and/or physically retained within the hair fibres. Alternatively or additionally, amide bonds may be formed between carboxylic acid groups or amino groups on the amino acids and amino groups or carboxylic acid groups which are present in or at the surface of the hair„.fibres . Thus, the amino acids may be chemically bound to the hair. Other groups which are present in or at the surface of the hair fibres (eg, thiol groups) may take part in this bonding.

As an alternative to, or in addition to, the amino acids, the one or more compounds may comprise: mono-, di-, tri-, or poly- carboxylic acids; mono-, and di-, tri-, or poly- amines; or mixtures thereof. Suitable inono-carboxylic acids and mono-amines include _± to C_ls saturated alkyl compounds, optionally substituted. Suitable dicarboxylic acids and diamines include compounds of the general formula X-A-X, where X is COOH or NH₂ and A is C₂ to C₁₆ alkylene, optionally substituted on the alkylene chain. Substituents include, for example, C_x to C₆ alkyl, hydroxyl, C to C₆ alkoxy, amino and carboxyl .

As a further alternative to, or in addition to, the amino acids, oligomers formed from amino acids may be used eg, protein fragments obtained by hydrolysis of longer chain proteins or oligomers preformed from "amino acids. Such oligomers may have an average chain length of, for example, from 2 to 100 (more preferably 2 to 50) amino acid residues.

The term alkyl, and related terms used herein, includes optionally substituted, branched and unbranched alkyl chains and, for C₃ upwards, cycloalkyl . Alkoxy and alkylene are defined similarly but refer to O-alkyl and divalent radicals derived from alkyl groups, respectively. Where the one or more compounds comprise only a mono- carboxylic acid or a mono-amine, or only a dicarboxylic acid or a diamine, the amide bond will be formed with an amino or carboxyl group, respectively, in or on the hair fibres.

Where the one or more compounds comprise a mixture of a dicarboxylic acid and a diamine, amide bonds may be formed between the dicarboxylic acid and the diamine to form an oligomer or polymer in or on the hair. The oligomer or polymer may be physically retained in or on the hair fibres or chemically bound on or within the hair fibres.

The Coupl ng Agent

The coupling agent promotes the formation of an amide bond to the one or more compounds, by reaction with the hair itself and/or by reaction with the one or more compounds. The coupling agent may be a single compound or a mixture of different compounds. Preferably, the coupling agent promotes the reaction to form .the amide bond by reaction in situ with the carboxylic acid group to form a derivative which then undergoes reaction with the amino group more readily than the underivatised carboxylic acid group. The coupling agent is suitably a compound which comprises a carbodiimide group.

Therefore, the coupling agent preferably has the formula R¹-N=C=N-R², where R¹ and R² are independently selected from C₁ to C_1S alkyl, optionally substituted

(eg, by amino, alkylamino or preferably dialkylamino groups) . The coupling agent is preferably soluble in water or alcohol solvents (non-limiting examples of which include ethanol, methanol, 1-propanol, 2-propanol or 1-butanol) or mixtures thereof. The coupling agent may be nonionic, anionic, cationic or zwitterionic .

The presence of charges on the coupling agent may help to boost solubility and/or to enhance compatibility with hair. Suitable coupling agents include, for example, l-ethyl-3- (3-dimethylaminopropyl) carbodiimide and 1, 1 ' -carbonyldiimidazole.

The coupling agent may be used in conjunction with one or more compounds which promote or accelerate the reaction to form amide bonds. Generally, these compounds have the effect of increasing the rate of the reaction to form amide bonds. Suitable compounds which promote or accelerate the reaction include, -.for example, N-hydroxy compounds such as an optionally substituted N-hydroxysuccinimide . Preferred substituted N-hydroxysuccinimides are those containing polar groups eg, N-hydroxysulphosuccinimide . The compound which promotes or accelerates the reaction to form amide bonds is preferably present in an amount such that the molar ratio of the compound to the one or more compounds capable of forming amide bonds ^* is ^"from 10:1 to 1:10, more preferably from 5:1 to 1:5, most preferably from 2:1 to 1:2.

Form of the Compositions

The compositions of the invention ^•are-preferably άn the form of solutions in water, alcohols or mixtures thereof. The one or more compounds will typically be present in the composition in an amount of from 0.001% to 10% by weight (preferably from 0.1% to 5% by weight) of the overall composition. Therefore, when the composition is in the form of a solution, the one or more compounds are typically present in the solution in an amount of from 0.01 to 100 g/1, more preferably from 1 to 50 g/1. The coupling agent is preferably present in a molar ratio of coupling agent: one or more compounds capable of forming amide bonds of from 1:5 to 5:1, more preferably 1:2 to 2:1, most preferably 1.5:1 to 1:1.5 (eg, about 1:1).

The compositions of the invention are preferably hair care compositions in a form suitable for application to hair, preferably human hair. The compositions may be packaged and labelled as such.

In order to avoid the possible problem of the coupling agent and the one or more compounds reacting to form amide* bonds before the compositions are applied to hair, the coupling agent and the one or more compounds may be packaged separately from one another in a packaged article of the invention. Thus, by packaging the two components (ie, the coupling agent and the one or more compounds) separately, no reaction of the coupling agent and the one or more compounds can take place until the two components are mixed to form a composition of the invention immediately prior to application to the hair. The packaged article may comprise a solution of the coupling agent and a solution of the- one or more compounds or may-comprise..a solution of one component with the other component in solid form. Alternatively or additionally, compounds which accelerate or promote the reaction (if used) may be packaged separately from other components of the composition, including the one or more compounds capable of forming amide bonds and/or the coupling agent, in the same way as the coupling agent and the one or more compounds may be packaged separately. Suitable two part packages, designed to allow mixing of the two components, are well-known, for example, in the field of hair colourants. Alternatively, one of the two components may be encapsulated, with the encapsulated material adapted to be released at an appropriate time. Method of the Invention

The compositions are preferably applied to human hair to form amide bonds, in si tu, on and/or in the hair.

The compositions may be used for cosmetic purposes, for example to improve the overall body of the hair. Thus, the treatment may increase one or more of the following properties of the hair: compression resistance (ie, the stiffness of the hair); volume; and thickness. The treatment may also decrease" ease σ^*f-' comb. Alternatively, the compositions may be used in the therapeutic treatment of human hair to deliver therapeutically beneficial compounds 'to the hair.

In applying the composition to hair according to the method of the invention, the hair is ^■ first preferably washed (eg, with shampoo) , rinsed and optionally dried (eg, by towel or hair dryer) . Alternatively, the composition can be applied to .w.e.t,.,or jdry... air ..prior ,fco washing. The composition is then applied to the hair, for example by dipping the hair "into- the compOsitlOn, by spraying the composition onto the hair or by rubbing the composition into the hair by hand. The exact method of application used in any given case will depend on the particular product form of the composition. Suitable treatment times are, for example, from 10 seconds to 2 hours, such as 10 minutes to 1 hour. This treatment may be carried out at room temperature but is preferably carried out at elevated temperatures (eg, 0 to 60°C) . It will be appreciated that the higher the temperature is, the lower the time which is required for this treatment step. Heating may be provided by a conventional hair dryer.

After the required amount of treatment, optionally the excess composition is washed or rinsed out of the hair and the hair may be dried (eg, in air or using a hair dryer) , optionally after having been styled.

Cosmetic and Personal Care Compositions

The compositions of the present invention are preferably formulated into hair care compositions, which can be in the form of a wide variety of product types, non-limiting examples of which include mousses_., gels, lotions, tonics, sprays, shampoos, conditioners, rinses and the like. The carriers and additional components required to formulate such products vary with product type and can be routinely chosen by one skilled in the art. The compositions may comprise a fragrance or perfume. The following is a description of some of these carriers and additional components.

Carriers

Hair care compositions of the present invention can comprise a carrier, or a mixture of such carriers, which are suitable for •■application to the •■^•■hair; The carriers are present at from about 0.5% to about 99.5%, preferably from about 5.0% to about 99.5%, more preferably from about 10.0% to about 9^'8.'O%, of the composition. As used herein, the phrase "suitable for application to hair" means that the carrier does not damage or negatively affect the aesthetics of hair or cause unacceptable irritation to the underlying skin. Carriers suitable for use with hair care compositions of the present invention include, for example, those used in the formulation of hair sprays, mousses, tonics, gels, shampoos, conditioners, and rinses. The choice of appropriate carrier will.^' also depend on the particular composition to be used (e.g., rinse, spray, mousse, tonic, gel) . The carriers used herein can include a wide range of components conventionally used in hair care compositions. The carriers can contain a solvent to dissolve or disperse the particular composition- being used, with water, the C₁-C₆ alcohols, lower alkyl acetate and mixtures thereof being preferred. The carriers can also contain a wide variety of additional materials such as acetone, hydrocarbons (such as isobutane, hexane, decene) , halogenated hydrocarbons (such as Freons) and volatile silicone derivatives such as cyelomethicone . When the hair care composition is a rinse, spray, tonic, gel, or mousse the preferred solvents include water, ethanol, volatile silicone derivatives, and mixtures thereof. The solvents used in such mixtures may be miscible or immiscible with each other. Mousses and aerosol hair sprays can also utilise any of the conventional propellants to deliver ,the material as a foam (in the case of a mousse) or as a fine, uniform spray (in the case of an aerosol spray) . Examples of suitable propellants include materials such as trichlorofluoromethane, dichlorodifluoromethane, difluoroethane, dimethylether, propane, --n- utane -or isobutane. A product having a low viscosity may also utilise an emulsifying agent. Examples of suitable emulsifying agents include nonionic, cationic, anionic surfactants, or mixtures thereof. If such an emulsifying agent is used, it is preferably present at a level of from about 0.01% to about 7.5% of the composition. The level of propellant can be adjusted as desired but is generally from about 3% to about 30% of mousse compositions and from about 15% to about 50% of the aerosol hair spray compositions.

Suitable spray containers are well known in the art and include conventional, non-aerosol pump sprays i.e., "atomisers", aerosol containers or cans having propellant, as described above, and also pump aerosol containers utilising compressed air as the propellant.

Where the hair, care compositions are rinses the carrier can include a wide variety of conditioning materials.

The carrier can be in a wide variety of forms . For example, emulsion carriers, including oil-in-water, water-in-oil, water-in-oil-in-water, and oil-in-water- in-silicone emulsions, are useful herein. These emulsions can cover a broad range of viscosities, e.g., from about 100 cps to about 200,000 cps . These emulsions can also be delivered in the form of sprays using either mechanical pump containers or pressurised aerosol containers using conventional propellants. These carriers can also be delivered in the form of a mousse. Other suitable topical carriers include anhydrous liquid solvents such as oils, alcohols, and silicones (e.g., mineral oil, ethanol, isopropanol, dimethicone, cyclomethicone, and the like) ; aqueous- based single phase liquid solvents (e.g., hydro- alcoholic solvent systems) ; and thickened versions of these anhydrous and aqueous-based single phase solvents (e.g., where the viscosity of the solvent has been increased to form a solid or semi-solid by the addition of appropriate gums, resins, waxes, polymers, salts, and the like) .

Additional Components

A wide variety of additional components can be employed in cosmetic and personal care compositions according to the present invention. Examples include the following:

- sunscreening agents such as 2-ethylhexyl p- methoxycinnamate, 2-ethylhexyl N, N-dimethyl-p- aminobenzoate, p-aminobenzoic acid, 2- phenylbenzimidazole-5-sulfonic acid, octocrylene, oxybenzone, homomenthyl salicylate, octyl salicylate, 4,4 ' -methoxy-t-butyldibenzoylmethane, 4-isopropyl dibenzoylmethane , 3 -benzylidene camphor, 3- (4- methylbenzylidene) camphor, titanium dioxide, zinc oxide, silica, iron oxide, and mixtures thereof.

anti-dandruff actives such as zinc pyrithione, piroctone olamine, selenium disulphide, sulphur, coal tar, and the like.

conditioning agents for hair care compositions such as hydrocarbons, silicone fluids, and cationic

, materials. The. hydrocarbons can be either straight or branched chain and can contain from about 10 to about 16, preferably from about 12 to about 16 carbon atoms. Examples of suitable hydrocarbons are decane, dodecane, tetradecane, tridecane, and mixtures thereof. Examples of suitable silicone conditioning agents useful herein can include either cyclic or linear polydimethylsiloxanes, phenyl and alkyl phenyl silicones, and silicone copolyols. JZationic conditioning agents useful herein can include quaternary ammonium salts or the salts of fatty amines.

surfactants for conditioner compositions and shampoos. The preferred level of surfactant is from about 0.2% to about 50%. Surfactants useful in compositions of the present invention include anionic, nonionic, cationic, zwitterionic and amphoteric surfactants .

carboxylic acid polymer thickeners. These crosslinked polymers contain one or more monomers derived from acrylic acid, substituted acrylic acids, and salts and esters of these acrylic acids and the substituted acrylic acids, wherein the crosslinking agent contains two or more carbon-carbon double bonds and derived from a polyhydric alcohol . Examples of carboxylic acid polymer thickeners useful herein are those selected from the group consisting of carbomers, acrylates/C₁₀-C₃₀ alkyl acrylate crosspolymers, and mixtures thereof. Compositions of the present invention can comprise from about 0.025% to about 1%, more preferably from about 0.05% to about 0.75% and most preferably from about 0.10% to about 0.50% of the carboxylic acid polymer thickeners.

emulsifiers for emulsifying the various carrier components of the compositions of the invention. Suitable emulsifier types include polyethylene- glycol 20 sorbitan monolaurate (Polysorbate 20) , polyethylene glycol 5 soya sterol , Steareth-20, Ceteareth-20, PPG-2 methyl glucose ether distearate, Ceteth-10, Polysorbate 80, cetyl phosphate, potassium cetyl phosphate, diethanolamine cetyl phosphate, Polysorbate 60, glyceryl stearate, PEG-100 stearate, and mixtures thereof. The emulsifiers can be used individually or as a mixture of two or more and can comprise from about 0-.••!%• to about 10%, more preferably from about 1% to about 7%, and most preferably from about 1% to about 5% of the compositions of the present invention.

vitamins and derivatives thereof (e.g., ascorbic acid, vitamin E, tocopheryl acetate, retinoic acid, retinol, retinoids, and the like) .

cationic polymers (e.g., cationic guar gum derivatives such as guar hydroxypropyltrimonium chloride and hydroxypropyl guar hydroxypropyltrimonium chloride, available as the Jaguar C series from Rhone- Poulenc) . preservatives, antioxidants, chelators and sequestrants; and aesthetic components such as fragrances, colourings, hair nutrients and essential oils.

The invention will now be illustrated by the following non-limiting Examples:

The accompanying drawings illustrate some of the examples .

Figure 1 is an SEM image of a hair fibre treated with the amino acid tryptophan in the presence of the coupling agent 1-ethyl-3- (3 -dimethylaminopropyX) carbodiimide (EDC) ;

Figure 2 is an SEM image of a nylon fibre treated in the same way as the hair fibre depicted in Figure i;

Figure 3 is an AFM image of the hair fibre shown in Figure 1;

Figure 4 is an SEM image of a hair fibre treated by dipping into solutions of tryptophan and EDC and drying at 50°C for 2 hours; and

Figure 5 is an SEM image of a nylon fibre treated in the same way as the hair fibre shown in Figure 4.

Examples

In the Examples, and throughout the specification, all percentages are percentages by weight unless indicated otherwise.

Materials The hair used was Spanish, dark brown hair. L- tryptophan and EDC were obtained from Fluka.

Synthesis of polytryptophan (Comparative Example)

In order to ascertain suitable polymerisation conditions, polytryptophan was first synthesised in a polymerisation vessel, as follows:

L-tryptophan is soluble in hot alcohol. ~A test of solubility showed that mixture of propan-2-ol :water (50:50) dissolves the monomer at 60°C. Under these conditions, 0.250 g of L-tryptophan requires 12 ml -of solvent .

1. A mixture of 0.251 g of L-tryptophan in .12..ml of solvent was stirred in a 50 ml jar for 1 h at 60°C.

2. After complete dissolution, 0.481 _g of EDC dissolved in 2 ml of water was added and the reaction maintained at 60°C for 4 h.

3. The j ar was then removed from the heat and the medium cooled down to room temperature .

4. The solvent was removed with a rotary evaporator.

Infra red spectroscopy was used to prove the structures of tryptophan and the polymerisation product.

Tn-situ polymerisation with tryptophan as monomer

(a) Preparation of hair

Before each experiment, hair was washed according to the following procedure. The shampoo used is a non- conditioning shampoo that removes dirt and grease from hair without depositing silicone, which would affect the sensory properties. Two successive washes of 30 s each were applied with 0.1 g of shampoo per g of- hair; the rinse time was also 30 s.

(b) Polymerisation methods

Three different methods for the formation of polytryptophan were tested and are outlined in the following table:

Example 1

1. Hair was soaked ^"in a solution of L-tryptophan for 1 h at 70°C.

2. A solution of EDC was then added to the medium and the mixture was stirred and held at 70°C for 2 h.

3. Finally, the hair was placed in the drying cabinet at 50-60°C for 2 h. Hair was analysed before being washed in shampoo. It was then reanalysed a-f er -the -wash.

Example 2

1. Hair was dipped in a solution of L-tryptophan

2. It was then dipped into the solution -of EDC "before being placed again in the drying cabinet (50-60°C) for 2 h.

Hair was analysed before a wash with shampoo. It was then reanalysed.

Example 3

EDC and tryptophan solutions were mixed at room temperature. It was then applied to the hair and left for 40 min at a) room temp and b) 50 °C. The hair was washed before a panel test was carried out .

Table 1: Summary of methods used to treat hair with L- tryptophan. In Examples 1 to 3 , the solution of L-tryptophan was a solution of 0.251g tryptophan in 12 ml 50% aqueous propan-2-ol. The solution of EDC was a solution of 0.481g EDC in 2 ml water.

(c) Analysis

To evaluate the efficiency of the in situ polymerisation, the following analyses are run:

- Diameter measurement before treatment, after treatment and after final wash

- Stiffness measurement before treatment, after treatment and after final wash - Scanning Electron Microscopy (SEM)

- Atomic Force Microscopy (AFM)

- Sensory Panel Tests

(d) SEM and AFM

Changes to the morphology of the hair surface were monitored using SEM and AFM. Nylon fibres -{of' 70 -μm diameter) were treated in parallel with the hair fibres and images obtained of the surface. This enabled comparison with a uniform, non-porous substrate. Nylon is suitable for such a comparison as it contains peptide linkages, as does hair, which may bond with the polymer during the in-situ reaction.

(e) Change in diameter

The diameters of the fibres were measured using a laser scanning micrometer (Ism) (ex Mitutoyo) . The detailed procedure is outlined below: 1. A hair fibre is attached between two metal crimps and left in a humidity controlled room overnight at 20°C and 50% relative humidity.

2. Its diameter is then measured using the Ism. Due to the fact that the diameter of a hair is not constant along its length, a measurement is taken in four places and an average value calculated.

3. The hair fibres are then treated according to the examples and replaced in the humidity controlled room overnight before new measurements are taken. A set of 20 fibres is used for each treatment.

4. Finally the fibres are washed with shampoo and again left overnight in the humidity room before final measurements are taken.

(f) Change in stiffness

The loop test was used to monitor changes in stiffness in the hair as a result of treatment . A brief outline of the procedure is given below.

1. A hair fibre, formed into a circular loop, is glued to a staple attached to a metal crimp.

2. To measure the stiffness, the crimp is held in the clamp of the micro-balance CAHN DCA-312™ and the platform on which the clamping arrangement is mounted moved down at a fixed speed (Imm/min) . The resulting load is then measured via a hook threaded through the top of the loop.

3. Stiffness is then calculated from the gradient of the resultant curve of force vs displacement. (g) Sensory panel testing

Overall body of a hair array may be assessed by looking at a number of key body related attributes . The- panel tests carried out in this study were primarily concerned with such body related attributes, although other sensory aspects such as softness and smoothness were also tested where appropriate.

The paired comparison method was used to obtain a measure of these sensory attributes .

An initial screen, called a balance, is used to evaluate the suitability of the switches for use in -the test as it is necessary that the switches are identical or nearly identical . Six switches are required for each test. Each switch is compared to each of ..the others in pairs for every attribute by 12 people . The results are then analysed with a statistics program. Once six switches have been chosen, three are washed with shampoo and the remaining three are treated. A panel test is then run to determine any •^•■'•signif cant differences between the treated and untreated switches.

Example 1

Hair (and nylon fibres) were treated as outlined in Table 1.

(a) SEM and AFM

SEM images of the treated hair and nylon fibres are shown in Figures 1 and 2, respectively. A continuous film coats the surface of both the^' hair and the nylon fibres. The nylon fibre has a slightly granular appearance in places. The coating of the surface of the hair is also confirmed by the AFM image shown in Figure 3.

The coating of the surface of the hair proves that an in-situ polymerisation has occurred under the conditions employed. Any monomer travelling inside the fibre may well have polymerised too, but this cannot be seen on these images .

(b) Change in diameter

The diameter changes upon polymerisation treatment are summarised in the table below.

Table 2 : Diameter changes in single hair fibres as a result of treatment with tryptophan and EDC according to Example 1. Also showing effect of subsequent wash..

An increase in diameter is observed which is reduced by the post treatment wash. This may be due in part to the deposition of surface polymer film (seen by SEM and AFM) and its subsequent removal by washing.

This provides further evidence that the in-situ polymerisation of tryptophan can be carried out on hair.

Example 2 The hair was dipped into the trytophan and EDC solutions in turn and dried at 50°C for 2 h (see Table

1) •

(a) SEM and AFM

SEM images of the treated hair and nylon fibres are shown in Figures 4 and 5, respectively.

The SEM image of the nylon fibre shows an interesting phenomenon. There is breakage of a layer on the surface, which proves that a film covers its surface. The hair fibre, however, shows no such morphology. It is possible that any film formed on the surface of the hair is discontinuous in nature (both along a single fibre and throughout a switch) . This was confirmed by an AFM image which showed film formation on the .hair fibre. The nylon fibre is impervious to the penetration of monomers and so any polymerisation will occur only on the surface. The hair fibre, however, will absorb monomer and therefore it is possible that the polymerisation has also occurred inside ..rather than on the surface of the fibre.

This example did not involve any soaking contact -with the reagents, but the dipping would still have allowed the take up of enough reagent to be equivalent to approximately a 10 min soak.

(b) Change in stiffness

The change in stiffness as a result of the polymerisation treatment is summarised in the table below. Stiffness was measured prior to treatment, immediately after treatment and following a post treatment wash.

Table 3 : Change in stiffness in hair fibres as a result of polymerisation treatment according to Example 2, after treatment and then after final wash.

At 95% confidence intervals, the mean of the set after the final wash is between 18.79% and 37.46%. We can, therefore, conclude that the stiffness is increased -by the treatment and that the increased stiffness is durable to a wash cycle. Without wishing to be bound by theory, this may be taken as evidence that polymerisation has occurred inside the hair shaft because any polymer formed within the hair fibre will be too large to leach out during washing; the hair fibre thus retains the higher stiffness level.

(c) Change in diameter

The diameter changes upon polymerisation treatment according to Example 2 are summarised in the table below.

Table 4 : Diameter changes in single hair fibres as a result of treatment with tryptophan and EDC following Example 2. Also showing effect of subsequent wash.

A small decrease in diameter is observed as a result of the treatment; the post treatment wash slightly reduces this diameter change.

(d) Sensory panel test

The effects of the polymerisation treatment on the sensory attributes of the hair switches treated according to Example 2 are summarised below. Panel tests were conducted directly after treatment and again following an application of conditioner (Organics™) .

Table 5 : Panel test result for hair treated under

Example 2 vs shampoo washed hair. Also showing effect of post wash conditioner application.

After treatment, the polymer treated hair has significantly more volume and thickness of feel than the shampoo washed hair. After the application of a conditioner, the polymer treated hair has significantly more body and thickness of feel.

These panel tests show that the tryptophan polymerisation treatment can be used to effect positive changes in sensory body related attributes of hair which are resistant to shampooing and conditioning.

Example 3

A panel test was run using hair under more realistic conditions. The solutions of EDC and tryptophan were mixed immediately prior to application to the hair. The solution was then left on the hair for 40 minutes at ambient temperature or 50°C. The reagents were then washed out of the hair and the hair allowed to dry. A panel test was run to determine the body related attributes of hair treated thus .

Table 6: Panel test for hair treated according to Example 3. At room temperature with these reagents, the polymerisation of tryptophan is slow and this is reflected in the properties of the hair - ease of comb and volume are low and there is no significant difference in compression resistance and stiffness between the treated and non-treated hair switches. At 50°C, however, evidence of polymerisation can be seen as resistance to compression is significantly higher for the treated hair and stiffness has also increased.

Example 4

A solution of EDC was prepared as in Examples 1 to 3. A solution of arginine was prepared using the- same solvent system used for tryptophan in Examples 1 to 3 and at the same molar concentration of amino acid.

The two solutions were mixed and maintained at 70 °C for 4 hours .

Hair was then soaked in the resulting solution for 1 -hour at -room temperature, removed -from -the solution • and dried overnight in a vacuum oven at 50 °C to 60°C.

SEM analysis of the treated hair shows homogeneous, thick deposition on the surface of the hair fibre.

Example 5

Example 4 was repeated using cysteine in place of arginine at the same molar concentrations.

SEM analysis of the treated hair shows a continuous film coating the surface of the hair fibre.

Example 6 In vivo tests were carried out as follows.

In a group of 20 models, each model's hair was washed with shampoo and dried with a towel. A solution ,- obtained by mixing a solution of tryptophan in 50% aqueous propan-2-ol (0.1M) with a solution of EDC in water (0.2M) was applied to hair on one side of the head and 50% aqueous propan-2-ol was applied to the other side as a control. The treated hair was left to soak for 5 minutes and was dried under a hood dryer for at least 20 minutes until the hair is dry. The hair was then washed with shampoo containing conditioner and dried.

The hair treated with the tryptophan/EDC solution was rated as being stiffer than the control by a significant majority of the models.

Example 7

L-Tryptophan (lg, 5mmol) and N-hydroxysuccinimide (0.575g, 5mmol) were dissolved in water (50ml)..at 7.0°C. To this solution was added a solution of EDC (0.9g, 5.5mmol) in water (1ml) and the mixture was stirred for 5 minutes whilst cooling to room temperature (22°C) .

Hair, prepared as described above, was dipped into the resulting mixture and kept at 22°C for 2 hours. The hair was then removed from the mixture and dried in a drying cabinet at 50-60°C for 4 hours.

The treated hair was analysed before and after being washed. SEM analysis revealed a coating on the hair both before and after washing.

Example 8 Example 7 was repeated but using an equimolar mixture of L-tryptophan and aspartic acid in place of L- tryptophan alone .

The treated hair showed a diameter increase of 1.8% and this increase disappeared after washing.

Example 9

Dry hair fibre was soaked in a solution prepared by dissolving arginine (5mmol) , N-hydroxysuccinimide

(0.575g, 5mmol) and 1, 1 ' -carbonyldiimidazole (CDI) (5.5 mmol) in water (50 ml) for 10 minutes at room temperature . The treated hair was then rinsed with tap water for 1 minute and dried at room temperature .

SEM analysis of the treated hair .fibre indicated that the contrast of the cuticles of the hair fibre is less definite, suggesting that the polymer has deposited to some extent on the hair fibre.

Example 10

Hair was soaked in a solution obtained by dissolving histidine (5 mmol) in water (50 ml) for 1 hour at 70 °C. To this mixture was added a solution of EDC (5.5 mmol) in water (1 ml) and the mixture was left to soak for an additional 4 hours at 70°C. The hair was removed from the mixture and dried at 50°C overnight.

SEM analysis revealed deposits on the surface of the hair fibre.

Example 11

Histidine (5 mmol) was dissolved in water (50 ml) for 1 hour at 70 °C. To this solution was added a solution of EDC (5.5 mmol) in water (1 ml) . The resulting mixture was maintained at 70°C for 4 hours. Hair was then dipped into the resulting mixture for 1 hour, then removed and dried at 50 °C overnight.

SEM analysis showed a continuous thin film coating the surface of the hair fibre.

Example 12

Example 11 was repeated using glycine in place of histidine.

SEM analysis of the treated hair showed a thick continuous film coating the surface of the hair.

Example 13

Example 11 was repeated using lysine in place of histidine.

SEM analysis showed a homogeneous . deposit -.a.t.. the surface of the hair fibre. The cuticles of the hair fibre had lost their contrast.

Examples 1.4 to 16

Examples 14 to 16 are examples of compositions according to the invention. The materials used were obtained from the following suppliers:

Example 14

The following is an example of a two part shampoo composition according to the invention:

Example 15

The following is an example of a two part conditioner according to the invention:

Example 16

The following is an example of a one part conditioner according to the invention:

In Examples 14 to 16, all materials are as 100 percent active and all percentages are by weight.

Example 17 ^ Tensile Strength Testing

A reaction of a variety of amino acids with EDC was carried out for 4h at 70°C. Hair was dipped in the resulting solution for lh at room temperature. Hair thus treated was placed in the oven overnight at 50- 60°C. Each hair fibre was attached between two metal crimps and left overnight at 20°C and at a humidity of 50%. Each fibre sample was fitted into a circular cassette (holding 100 samples) and was automatically selected to be stretched to break by the Diastron Miniature Tensile Tester (MTT) at a rate of 300mm/min. The maximum force was set to 1000, and the gauge force set to 2. Data was processed to display plots of extension as a function of applied force. Manual selection of the linear portion of these plots closely corresponded to the elastic response of the fibre. The mean slope allowed the elastic moduli to be determined after inputting cross-sectional area. The force required to stretch the fibre 1mm is indicative of overall hair -strength irrespective of diameter, whilst the elastic modulus indicates an intrinsic mechanical property of the fibre material. The plateau force, yield force .and .% extension, along with break point force and % extension were also determined from the plots. Fibres treated were compared to fibres which underwent the same treatment time and temperature, but were treated only with water. A second measurement was carried -out • for some treatments by immersing the fibres after treatment in water and measuring the force to stretch the fibres. The results were as follows:

Am no Acid % Change in Modulus

Arginine 2

Cysteine 0 Histidine 7

Glutamic acid 7

Glycine 9

Lysine 5

Fibres treated with histidine and arginine were then investigated after washing with a standard shampoo, to determine whether the change in modulus survived. The results were as follows:

Amino Acid % Change in Modulus Before washing After washi g Arginine 2 9

Histidine 7 4

The results showed that the effect on the modulus survived washing. The increase for arginine over the before wash result is likely to just be caused -by spread in the results. No other parameter on the stretch to break curve was significantly different from the control .

For these reasons, the combination of arginine with EDC as coupling agent and N-hydroxysuccinimide is -the currently most preferred composition of the invention.

Claims

1. Cosmetic and/or personal care composition comprising a coupling agent, one or more compounds capable of forming an amide bond as a result of a reaction involving the coupling agent and a cosmetically acceptable diluent and/or carrier.

2. Composition as claimed in Claim 1 which is a hair care composition in a form suitable for application to hair further comprising one.,,or more surfactants and/or fragrances .

3. Composition as claimed in Claim 1 or Claim 2j wherein the coupling agent promotes the formation of an amide bond between a carboxylic acid group and an amino group .

4. Composition as "claimed -in Claim 3, -wherein -the coupling agent comprises a carbodiimide group.

5. Composition as claimed in Claim 4, -wherein the coupling agent is l-ethyl-3- (3- dimethylaminopropyl) carbodiimide.

6. Composition as claimed in Claim 4, wherein the coupling agent is 1, 1 ' -carbonyldiimidazole .

7. Composition as claimed in any one of Claims 1 to 6, wherein the molar ratio of coupling agent to one or more compounds capable of forming amide bonds is from 1:5 to 5:1.

8. Composition as claimed in Claim 7, wherein the molar ratio is from 1:2 to 2:1.

9. Composition as claimed in any one of Claims 1 to

8 , wherein the one or more compounds capable of forming an amide bond comprise carboxylic acid and/or amino groups .

10. Composition as claimed in any one of Claims 1 to

9, wherein the one or more compounds capable of forming an amide bond are selected from mono- and di- carboxylic acids, mono- and di- amines, amino acids and mixtures thereof .

11. Composition as claimed in Claim 10, wherein the one or more compounds capable of forming an amide bond are one or more amino acids .

12. Composition as claimed in Claim 11, wherein the amino acids are natural amino acids or derivatives thereof .

13. Composition as claimed in any one of Claims 1 to 12, wherein the coupling agent and/or the one or more compounds are in the form ..of solutions.

14. Composition as claimed in Claim 13, wherein the solvent for the solutions is selected- -from "water, mono-, di, tri, or poly- hydric alcohols, ethers, esters and mixtures thereof.

15. Composition as claimed in any one of Claims 1 to 14 , wherein the one or more compounds are present in the composition in an amount of from 0.001% to 10% by weight.

16. Composition as claimed in Claim 15, wherein the one or more compounds are present in the composition in an amount of from 0.1% to 5% by weight .

17. Composition as claimed in any one of Claims 1 to 16, further comprising at least one compound which promotes or accelerates the reaction to form amide bonds .

18. Composition as claimed in Claim 17, wherein the compound which promotes or accelerates the reaction to form amide bonds is an optionally substituted N-hydroxysuccinimide .

19. A packaged article comprising separately packaged first and second parts, the first and second parts being capable of being mixed to form a composition as claimed in any one of Claims 1 to 18, the first part comprising the coupling agent and the second part comprising the one or more compounds capable of forming an amide bond.

20. A packaged article comprising separately packaged first and second parts, the first and second parts being capable of being mixed to form a .composition as claimed in Claim 17 or Claim 18', the first part comprising the at least one compound which promotes or accelerates the reaction to form-amide bonds and the second part comprising the coupling agent and/or the one or more compounds capable of forming an amide bond.

21. A method of treating hair which comprises applying to the hair a composition as claimed in any one of Claims 1 to 18.

22. A method as claimed in Claim 21 which is cosmetic.

23. Composition of any one of Claims 1 to 18 for use in a therapeutic method of treating hair.

24. Use of a composition of any one of Claims 1 to 18 in the cosmetic treatment of hair.

25. Use as claimed in Claim 24, wherein the treatment increases the compression resistance and/or the volume and/or the thickness and/or the strength of the hair and/or decreases the ease of comb of the hair.

26. Use of a composition of any one of Claims 1 to 18 in the manufacture of an agent for the therapeutic treatment of hair.