The present invention relates to a hair styling composition which is able to semi-permanently restructure hair. The composition is in the form of a leave-on treatment, which is easy to spread through hair without dripping but does not come into contact with the scalp once applied.

Managing, controlling and styling unruly hair is something faced by many people on a daily basis, and a major concern to consumers is the significant amount of time which is regularly spent using blow-dryers and straightening irons in order to achieve the desired look.

Hair styling products have been commercially available for many years in the form of sprays, mousses, gels, balms and serums. However, these products are only able to provide a temporary solution to the problem of hair manageability and style hold, and their effects are removed when a person next washes their hair with shampoo. This means a person has to repeat the whole process after every wash.

However, excessive use of blow-dryers and straightening irons can cause damage to hair. This can result in a loss of smoothness and lustre and even breakage of the hair in extreme cases.

In order to overcome these problems, it is common in the art for hair to be chemically treated with a reducing agent. Typically, such reducing agent treatments involve breaking some of the disulphide linkages in the keratin in a person's hair, reshaping the hair in some manner, and then subsequently recombining the disulphide linkages in a new configuration. Reducing agents which are commonly used in these treatments are thioglycolic acid and its salts. In order to fix the hair in its new style, it is further treated with an oxidising agent, such as hydrogen peroxide, to recombine the disulphide linkages. However, thioglycolic acid and its salts can act as an irritant to a person's skin and can also have a strong unpleasant odour. Furthermore, the process requires the application of a strong oxidising agent - typically hydrogen peroxide - as part of a second neutralising step, which is damaging to hair.

In addition to the use of thioglycolates, salts of sulphur oxo-acids, such as sulphites and/or bisulphites, have also been employed commercially as the reducing agents in chemical treatment systems. These systems have advantages over the thioglycolate-based systems. They are safer for a user as they are less of a skin irritant, they emit a reduced odour, and systems comprising them only require a single step to achieve the desired result.

With both thioglycolate- and sulphur oxo-acid-based systems, the treatment only needs to be reapplied approximately every 4-6 weeks.

There are many similar hair management systems to those described above, but all involve the use of lotions and gels. Using lotions and gels has the disadvantage that they do not hold the hair in place during application of the treatment, and they additionally have a tendency to drip onto the scalp and onto the user's clothing.

EP 0 304 846 discloses a composition for enhancing the body of hair, comprising as essential ingredients, in certain critical amounts, an alkali metal or ammonium bisulphite, an alkanolamine, a guar hydroxypropyltrimonium chloride, a certain quaternary ammonium conditioner, an alkali metal or ammonium carbonate or an alkali metal phosphate and water; and a method of use thereof. US 2006/0251599 discloses a process and composition for straightening or waving hair that is achieved by combining ammonium bisulphite and ethanolamine sulphite in a single mixture which is maintained at a pH of between about 6.5 and 8.0.

US 4,038,995 discloses a hair treating composition for waving and straightening hair that comprises from about 0.5 to 15% by weight of a reducing agent selected from the group consisting of ammonium and sodium sulphites and bisulphites and from about 0.1 to about 5.0% by weight of a quaternary ammonium salt of a mink oil fatty acid and has a pH between 6.5 and 6.9.

EP 0 190 834 discloses a hair waving and straightening treatment composition comprising a sulphite and/or bisulphite reducing system, urea in amount of at least 10% by weight and a cationic polyquaternary having a conductivity, when measured at 0.1% by weight concentration, from 225 mhos to 25 mhos, in an amount of at least 0.07% by weight. It is the combination of urea and the cationic polyquaternary is needed to provide enhanced curl tightness.

It is therefore desirable to provide a hair styling composition which is able to overcome the above-mentioned problem of dripping onto a person's scalp and clothing, and which holds hair better in place during treatment.

According to the present invention there is provided a hair styling composition comprising:

a) a salt of a sulphur oxo-acid;

b) a non-ionic emulsifier; and

c) a styling polymer,

wherein the composition is in the form of a cream. The problems associated with the prior art can be overcome by the incorporation of the sulphur oxo-acid salt into a cream with shear thinning rheology, i.e. the viscosity of the cream decreases with increasing mixing shear rates. Because of the shear thinning rheology, it is easy to spread through hair without dripping while also not coming into contact with the scalp once it has been applied.

In contrast to e.g. a lotion, a shear thinning cream has a very high level of viscosity at rest. It is therefore not a pourable substance and does not drip from the hair once applied thereto, thus increasing the contact time of the product with the hair, and consequentially also increasing the product's effectiveness.

While EP 304846 mentions that its compositions may be obtainable as

'creams' by adding 0.5-1.5 wt.% of an opacifier (either an anionic surfactant, or an anionic surfactant in combination with a non-ionic surfactant), the compositions obtained are not actually creams; rather they are opacified gels.

The composition of the invention provides a means of semi-permanently restructuring hair in the form of a leave-on styling treatment. It can be used to semipermanently straighten, wave, curl, or otherwise style a person's hair. It enables a user to style his or her hair without needing to use undesirable thioglycolic acid or its salts, without needing to use any strong oxidising agent. It also makes the hair more manageable, reducing the time and effort required to style the hair, allows for more control over removing 'frizz' from the hair and smoothing it, and it gives the hair a smoother texture. Products are commercially available which are directed towards control of frizzy hair or to provide a smoother hair texture, but such products do not also allow for the reshaping of the hair. Also, the composition of the invention is able to maintain the style of the hair and hold it for about 4-6 weeks. The inclusion of a specialist styling polymer in the composition enhances the restructuring effect on the hair, and provides additional hold during the time the composition is applied to the hair during the treatment.

According to one embodiment of the invention, the composition substantially does not contain any urea, as it does not require it in order to provide the desired styling properties. By "substantially does not contain any urea" it is meant that the composition comprises no urea which is specifically added to the components (a)-(c) above, and that any urea present in the composition is present as an impurity and in trace amounts only.

Typical, but non-limiting, components of the composition of the invention are explained in more detail below.

Salt of a sulphur oxo-acid

The composition of the invention comprises one or more salts of a sulphur oxo-acid which are included as reducing agents to cleave the disulphide linkages present in hair.

Typically, the salts of a sulphur oxo-acid may include, but are not limited to, alkali metal and ammonium salts of sulphites, hydrogen sulphites, disulphites, dithionites, and mixtures of any two or more thereof.

Typically, sulphite, bisulphite or disulphite salts are used, either individually or in admixture. More typically, alkali metal or ammonium salts of sulphites or bisulphites are used, either individually or in admixture.

More typically, sodium sulphite and/or ammonium bisulphite is used. The total amount of the salt of a sulphur oxo-acid present in compositions of the invention may typically range from about 0.5 to about 15%, more typically about 2 to about 10%, most typically about 5 to about 10% by weight, based upon the total weight of the composition.

Non-ionic emulsifier

The composition of the invention comprises one or more non-ionic emulsifiers which are included to produce a cream with shear thinning rheology.

Non-limiting examples of suitable non-ionic emulsifiers which may be used in the composition of the present invention are provided below. Any of these non-ionic emulsifiers may be used, either individually or in an admixture of any two or more thereof. The non-limiting examples below are described using INCI (International Nomenclature of Cosmetic Ingredients) nomenclature:

(1) Esters of glycerin such as glyceryl stearate;

(2) Esters of fatty acids such as isostearyl isostearate;

(3) Ethoxylated fatty alcohols such as ceteth-20, steareth-20 and PEG-2 stearate;

(4) Hydrogenated plant oil derivatives such as hydrogenated palm kernel glycerides.

More typically, the non-ionic emulsifier used is glyceryl stearate and/or steareth-20.

The total amount of non-ionic emulsifier present in compositions of the invention may typically range from about 2 to about 20%, more typically about 5 to about 15%, most typically about 5 to about 10% by weight, based upon the total weight of the composition.

Styling polymer

The composition of the present invention comprises one or more styling polymers which are included to increase the longevity of hold to the hair during the treatment period.

According to one embodiment, suitable styling polymers for use in the compositions of the invention include, but are not limited to, homopolymers, copolymers or terpolymers, either individually or in a combination of any two or more polymers. Non-limiting examples of styling polymers that can be used in the present invention are provided below:

(1) Homopolymers of vinylpyrrolidone;

(2) Homopolymers of vinylcaprolactam;

(3) Copolymers of vinylpyrrolidone and vinyl acetate;

(4) Terpolymers of vinylcaprolactam, vinylpyrrolidone and dimethylaminoethyl methacrylate;

(5) Imidised isobutylene and maleic anhydride copolymers;

(6) Copolymers of isobutylene, dimethylaminopropyl maleimide, ethoxylated maleimide and maleic acid;

(7) Copolymers of monoalkyl esters of polymethylvinyl ether and maleic acid;

(8) Copolymers of isobutylene/dimethylaminopropylmaleimide/ethoxylated maleimide/maleic acid. Any one of these styling polymers, or any two or more in combination may be used in the composition. More typically, the styling polymer is a copolymer of vinylpyrrolidone and vinyl acetate, or an isobutylene/dimethylaminopropylmaleimide/ ethoxylated maleimide/maleic acid copolymer.

The total amount of styling polymer present in the compositions of the invention may typically range from about 0.1 to about 10%, more typically from about 0.1 to about 5%, most typically from about 0.1 to about 2% by weight, based upon the total weight of the composition.

According to a further embodiment, the composition of the invention may contain one or more additional reducing agents that are typically used in hair perm treatments. These reducing agents are generally added at a level of 10%> or less, more typically at a level of 9 or 8% or less, by weight of the total composition. Non- limiting examples of these reducing agents could include thiols such as thioglycolic acid, glyceryl monothioglycolate, cysteine, cysteamine, glutathione, and glyceryl thiolactate.

The composition of the invention may also contain one or more further optional additional ingredients that are typically used in personal care products for the purpose of e.g. preservation, rheology modification, conditioning, pH control, colouring, etc. These ingredients are generally added at a level of about 5% or less by weight of the total composition. Non-limiting examples of these optional ingredients and their respective potential roles are provided below:

(1) Fatty alcohols, which are used to provide a creamy consistency to the composition and facilitate its application onto the hair. Non-limiting examples include cetyl alcohol, stearyl alcohol, myristyl alcohol, behenyl alcohol (docosanol), etc.

(2) Chelating agents, which remove dissolved metal ions that can accelerate the oxidation of the sulphur oxo-acid salts. Non-limiting examples include the salts of EDTA, gluconic acid, etc;

(3) Anti-oxidants, which inhibit the reaction of oxygen with the sulphur oxo- acid salt. Non-limiting examples include BHT (butylated hydroxytoluene), BHA (butylated hydroxyanisole), vitamin C, etc;

(4) Preservatives such as isothiazolinones, parabens, salts of organic acids, etc., to prevent the growth of microorganisms;

(5) Conditioning polymers such as silicones and polymeric quaternary ammonium compounds are added to improve the feel of hair;

(6) Rheology modifiers such as cellulose derivatives, natural gums, finely divided silica, inorganic clays, etc., to improve the texture of the composition;

(7) pH adjusters such as alkali metal and ammonium hydroxides, citrates, phosphates, lactates, etc., to ensure that the pH is maintained between specified limits, i.e. between about 6-8;

(8) Protein hydrolysates derived from keratin and plant sources used to provide damage protection to hair;

(9) Fragrance, in addition to its obvious function, provides a means to mask the odour produced when sulphur reducing agents react with hair. According to a further embodiment of the invention, there is also provided a method of treating and/or styling hair comprising applying a composition as described hereinabove.

Typically, the method comprises applying to the hair a composition as described hereinabove, allowing the composition to remain in contact with the hair for up to about 30 minutes, rinsing the hair sufficiently to remove the composition, and styling the hair into a desired shape. The styling is typically carried out using blow drying and/or straightening irons, curling tongs or curlers/rollers.

Optionally, a conditioning agent may be applied after the composition of the invention has been rinsed off. If applied, the conditioning agent is typically applied for about two minutes before being rinsed off. The conditioning agent is not part of the composition of the invention but can be provided separately. A conditioning agent used in conjunction with the composition of the invention may typically include, for example, conventional conditioning agent components, such as, but not limited to, cetyl trimethyl ammonium chloride, and/or behenyl trimethyl ammonium chloride.

An exemplary but non-limiting method of treating hair using the composition comprises applying the composition to the hair, leaving it in place for no more than about half an hour, and rinsing the composition off. A conditioning agent is then applied to the hair for about two minutes before being rinsed off. The hair is then blow dried and styled into the desired shape. The use of straightening irons, curling tongs or curlers/ rollers is a further optional step to obtain the desired style.

According to a further embodiment of the invention, there is also provided a method of manufacturing a composition comprising a salt of a sulphur oxo-acid, a non-ionic emulsifier and a styling polymer, wherein the composition is in the form of a cream, as described hereinabove, comprising mixing the salt of a sulphur oxo-acid, the non-ionic emulsifier and the styling polymer.

Typically, the method comprises the steps of:

i) mixing a non-ionic emulsifier and a fatty alcohol and heating the mixture to about 70-80°C;

ii) dispersing one or more rheology modifiers in water and heating the resultant dispersion to about 70-80°C;

iii) Mixing together the mixture of step (i) and the dispersion of step (ii) to form a homogeneous mixture;

iv) Allowing the homogeneous mixture to cool to about 40°C or less;

v) Adding a salt of a sulphur oxo-acid and mixing it into the homogeneous mixture;

vi) Adjusting the pH to about 6-8;

vii) Adding a styling polymer and mixing it into the homogeneous mixture. Any further optional ingredients may subsequently be added and mixed into the homogeneous mixture.

According to one non-limiting and purely exemplary embodiment of the invention, the composition of the invention may be prepared in accordance with the following general procedure:

1. Rheology modifiers are dispersed into water (phase A) and the dispersion is heated to 70-80°C;

2. A non-ionic emulsifier and a fatty alcohol (phase B) are combined and heated to 70-80°C; 3. Phase A and Phase B are mixed together until a homogeneous mixture is formed;

4. The resultant homogeneous mixture is allowed to cool down to less than 40°C;

5. A salt of a sulphur oxo-acid is added to the homogeneous mixture and is mixed in until it is fully dispersed in the mixture;

6. The pH of the mixture is adjusted to 6.5-7.5 using an alkali metal hydroxide solution;

7. A styling polymer is added to the homogeneous mixture and is mixed in until it is fully dispersed in the mixture;

8. Any further optional ingredients are then added and mixed in until they are fully dispersed in the mixture.

The compositions of the invention are adapted for use by a person either in a hair or beauty salon or at home. It has an advantage over other existing hair styling products in that it enables a person to use it at home, safely and unsupervised, without risk to the integrity and well-being of their hair, and achieve the desired hair style, rather than be dependent upon a professionally trained stylist.

The invention can be described further by way of example with reference to the following Examples which are intended to be illustrative only and in no way limiting upon the scope of the invention.

Examples

Table 1 illustrates four compositions, I-IV, in accordance with the invention, each comprising one or more sulphur oxo-salts, a non-ionic emulsifier and a styling polymer in the respective defined quantities. Table 1

*Based on 100% active ingredient To test efficiency, compositions of the present invention were applied to the hair of 12 independent panellists according to the method detailed above. After 4 weeks each panellist was asked about the degree to which they agreed or disagreed with a number of statements about the treatment. The results are shown in Table 2 below in terms of the percentage of panellists who gave a score of 4 or 5 (1 = Disagree Strongly; 5 = Agree Strongly).

Table 2

It can therefore be seen that the majority of the panellists agreed or strongly agreed that blow drying their hair became effortless after application of the composition; that the time they needed to style their hair was dramatically reduced; that their hair became much more manageable since the treatment; that the treatment smoothes and controls frizz in the hair; that the treatment gave their hair a smooth texture; and that the treatment is able to last up to 4 weeks.

It is of course to be understood that the present invention is not intended to be restricted to the foregoing examples which are described by way of example only.