WO2015003878A1

WO2015003878A1 - Shampoo composition

Info

Publication number: WO2015003878A1
Application number: PCT/EP2014/062758
Authority: WO
Inventors: Ningning LI; Cesar Ernesto MENDOZA FERNANDEZ; Jordan Todorov Petkov; Neil Scott Shaw; Donald Stewart
Original assignee: Unilever Plc; Unilever N.V.; Conopco, Inc., D/B/A Unilever
Priority date: 2013-07-12
Filing date: 2014-06-17
Publication date: 2015-01-15

Abstract

The invention provides a conditioning shampoo composition having: (a) an aqueous continuous phase including cleansing surfactant, and (b) a conditioning gel network which is dispersed in the aqueous continuous phase; in which the conditioning gel network is formed from lamellar or vesicular solid crystalline fatty material; and characterized in that the conditioning gel network is stabilized in the aqueous continuous phase by the inclusion of one or more osmolytes. The compositions demonstrate improved temperature stability and functionality even after exposure to temperature cycles.

Description

SHAMPOO COMPOSITION

Field of the Invention The present invention relates to a conditioning shampoo composition with improved stability.

Background and Prior Art In order to provide hair conditioning benefits in a cleansing shampoo base, a wide variety of conditioning actives have been proposed. However, many of these actives have the disadvantage of leaving the hair feeling soiled or coated and of interfering with the cleansing efficacy of the shampoo. Gel networks have been proposed for inclusion in shampoo compositions to achieve improved wet feel and dry conditioning whilst not interfering with cleansing efficacy. The term "gel network" refers to a lamellar or vesicular solid crystalline phase which is dispersed in the aqueous cleansing phase of the shampoo. An example of such a shampoo is described in WO2007/040571 , in which the dispersed gel network phase comprises bilayers made up of a first layer comprising fatty amphiphile and secondary surfactant and alternating with a second layer comprising water or other suitable solvent.

The preparation of conditioning shampoos using cationic gel phases is difficult due to inherent opposing charge interactions, which results in the gel phase interacting with the cleansing part. The gel components tend to disassemble to form crystalline structures that do not provide conditioning benefits. Moreover such crystalline phases also lower the viscosity of the product and result in phase separation. WO2010/052092 describes the preparation of conditioning shampoos using anionic gel phases. This improves the lifetime of the gel phase while it is dispersed in the cleansing part of the product. Despite the prior art there remains a need for more stable hair cleansing and conditioning shampoo compositions. In particular there remains a need for hair cleansing and conditioning shampoo compositions which retain their stability and functionality even after exposure to temperature cycles, such as for example during transport, storage and on shelf.

The present invention addresses this problem. Summary of the Invention The present invention provides a conditioning shampoo composition having:

(a) an aqueous continuous phase including cleansing surfactant, and

(b) a conditioning gel network which is dispersed in the aqueous continuous phase; in which the conditioning gel network is formed from lamellar or vesicular solid crystalline fatty material; and characterized in that the conditioning gel network is stabilized in the aqueous continuous phase by the inclusion of one or more osmolytes. Detailed Description and Preferred Embodiments

All molecular weights as used herein are weight average molecular weights, unless otherwise specified.

The term "cationic charge density", as used herein, refers to the ratio of the number of positive charges on a monomeric unit of which a polymer is comprised to the molecular weight of the monomeric unit. The charge density multiplied by the polymer molecular weight determines the number of positively charged sites on a given polymer chain.

By "aqueous continuous phase" is meant a continuous phase which has water or an aqueous solution or a lyotropic liquid crystalline phase as its major component.

Suitably, the conditioning shampoo composition of the invention will comprise from 10% to 98%, preferably from 30% to 95% water (by weight based on the total weight of the composition). The conditioning shampoo composition of the invention has an aqueous

continuous phase (a) including cleansing surfactant.

The cleansing surfactant may suitably be selected from one or more anionic surfactants.

Typical anionic surfactants for use as cleansing surfactants in the invention include those surface active agents which contain an organic hydrophobic group with from 8 to 14 carbon atoms, preferably from 10 to 14 carbon atoms in their molecular structure; and at least one water-solubilising group which is preferably selected from sulphate, sulphonate, sarcosinate and isethionate. Specific examples of such anionic surfactants include ammonium lauryl sulphate, ammonium laureth sulphate, trimethylamine lauryl sulphate, trimethylamine laureth sulphate, triethanolamine lauryl sulphate, trimethylethanolamine laureth sulphate, monoethanolamine lauryl sulphate, monoethanolamine laureth sulphate, diethanolamine lauryl sulphate, diethanolamine laureth sulphate, lauric

monoglyceride sodium sulphate, sodium lauryl sulphate, sodium laureth sulphate, potassium lauryl sulphate, potassium laureth sulphate, sodium lauryl sarcosinate, sodium lauroyl sarcosinate, lauryl sarcosine, ammonium cocoyl sulphate, ammonium lauroyl sulphate, sodium cocoyl sulphate, sodium lauryl sulphate, potassium cocoyl sulphate, potassium lauryl sulphate, monoethanolamine cocoyl sulphate, monoethanolamine lauryl sulphate, sodium tridecyl benzene sulphonate, sodium dodecyl benzene sulphonate, sodium cocoyl isethionate and mixtures thereof.

A preferred class of anionic surfactants for use as cleansing surfactants in the invention are alkyl ether sulphates of general formula:

R-O-(CH₂CH2-O)n-SO3^"M⁺ in which R is a straight or branched chain alkyl group having 10 to 14 carbon atoms, n is a number that represents the average degree of ethoxylation and ranges from 1 to 5, preferably from 2 to 3.5, and M is a alkali metal, ammonium or alkanolammonium cation, preferably sodium, potassium, monoethanolammonium or triethanolammonium, or a mixture thereof.

Specific examples of such preferred anionic surfactants include the sodium, potassium, ammonium or ethanolamine salts of C-m to C12 alkyl sulphates and C-m to C12 alkyl ether sulphates (for example sodium lauryl ether sulphate), Mixtures of any of the above described materials may also be used.

In a regular shampoo composition according to the invention the level of cleansing surfactant will generally range from 5 to 26% (by weight based on the total weight of the composition), while for concentrated compositions the level of cleansing surfactant will generally range from 27 to 70% (by weight based on the total weight of the composition).

The conditioning shampoo composition of the invention has a conditioning gel network (b) which is dispersed in the aqueous continuous phase. The

conditioning gel network is formed, inter alia, from lamellar or vesicular solid crystalline fatty material.

A preferred type of conditioning gel network in the context of the present invention has no overall charge or is anionic. Such a gel network is described in

WO2010/052092, and is formed from:

(I) fatty material,

(II) anionic surfactant comprising an alkyl group with from 16 to 30 carbons (hereinafter termed a "gel network anionic surfactant"), and

(III) cationic surfactant.

By "fatty material" is generally meant a compound having the general formula R-X, wherein R is an aliphatic carbon chain and X is a functional group (e.g. alcohol or carboxylic acid or a derivative thereof such as ester or amide).

R is preferably a saturated aliphatic carbon chain comprising from 8 to 30 carbon atoms, preferably from 14 to 30 carbon atoms, more preferably from 16 to 22 carbon atoms. R can contain, in addition to carbon and hydrogen atoms, ether linkages, and other groups such as amino groups. Preferably R is a hydrocarbon chain.

X is preferably an -OH group.

Most preferably, the fatty material (I) is a fatty alcohol of general formula

CH3(CH₂)n OH, where n is an integer from 7 to 29, preferably from 15 to 21 .

Specific examples of suitable fatty alcohols are cetyl alcohol, stearyl alcohol, behenyl alcohol, and mixtures thereof.

The level of fatty material (I) in compositions of the invention generally ranges from 0.01 to 10% and preferably ranges from 0.1 to 5% (by weight based on the total weight of the composition).

Typical anionic surfactants for use as the gel network anionic surfactant (II) in compositions of the invention include those surface active agents which contain an organic hydrophobic group with from 16 to 30 carbon atoms, preferably from 16 to 22 carbon atoms in their molecular structure; and at least one water-solubilising group which is preferably selected from sulphate and sulphonate.

A preferred class of anionic surfactants for use as the gel network anionic surfactant (II) in the invention are alkyl sulphates of general formula: R-O-SO₃ ^"M⁺ in which R is a straight or branched chain alkyl group having 16 to 22 carbon atoms and M is a alkali metal, ammonium or alkanolammonium cation, preferably sodium, potassium, monoethanolammonium or triethanolammonium, or a mixture thereof. Specific examples of such preferred gel network anionic surfactants (II) include the sodium, potassium, ammonium or ethanolamine salts of C16 to Cie alkyl sulphates (for example sodium cetostearyl sulphate),

Mixtures of any of the above described materials may also be used.

The gel network anionic surfactant (II) imparts an overall anionic charge to the gel network or no overall charge to the gel network. It is generally incorporated at levels ranging from 0.1 to 5% by weight of the composition and more preferably from 0.5 to 2.0% (by weight based on the total weight of the composition).

Suitable cationic surfactants (III) for use in the invention correspond to the following general formula:

[N(R¹)(R²)(R³)(R⁴)]+ (X)- in which R¹, R², R³, and R⁴ are each independently selected from (a) an aliphatic group of from 1 to 22 carbon atoms, or (b) an aromatic, alkoxy, polyoxyalkylene, alkylamido, hydroxyalkyi, aryl or alkylaryl group having up to 22 carbon atoms; and X is a salt-forming anion such as those selected from halide, (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.

Specific examples of such quaternary ammonium cationic surfactants of the above general formula are cetyltrimethylammonium chloride, behenyltrimethylammonium chloride (BTAC), cetylpyridinium chloride, tetramethylammoniunn chloride, tetraethylammoniunn chloride, octyltrimethylammonium chloride,

dodecyltrimethylannnnoniunn chloride, hexadecyltrimethylammonium chloride, octyldimethylbenzylannnnoniunn chloride, decyldimethylbenzylammonium chloride, stearyldimethylbenzylammonium chloride, didodecyldimethylammonium chloride, dioctadecyldimethylammonium chloride, tallowtrimethylammonium chloride, cocotrimethylammonium chloride, dipalmitoylethyldimethylammonium chloride, PEG-2 oleylammonium chloride and salts of these, where the chloride is replaced by other halide (e.g., bromide), acetate, citrate, lactate, glycolate, phosphate nitrate, sulphate, or alkylsulphate.

In a preferred class of cationic surfactant of general formula (I), R¹ is a C~i6 to C22 saturated or unsaturated, preferably saturated, alkyl chain and R², R³ and R⁴ are each independently selected from CH₃ and CH₂CH₂OH, preferably CH₃.

Specific examples of such preferred quaternary ammonium cationic surfactants for use in the invention are cetyltrimethylammonium chloride (CTAC) and

behenyltrimethylammonium chloride (BTAC). Mixtures of any of the foregoing materials may also be suitable.

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

unsubstituted. These amines are typically used in combination with an acid to provide the cationic species.

A preferred class of amine corresponds to the following general formula:

R¹- C(O) - N(H)- R² - N(R³)(R⁴) in which R¹ is a fatty acid chain containing from 12 to 22 carbon atoms, R² is an alkylene group containing from one to four carbon atoms, and R³ and R⁴ are each independently, an alkyl group having from one to four carbon atoms.

Specific examples of suitable materials of general formula (II) are

stearamidopropyldimethylamine, stearamidopropyldiethylamine,

stearamidoethyldiethylamine, stearamidoethyldimethylamine,

palmitamidopropyldimethylamine, palmitamidopropyldiethylamine,

palmitamidoethyldiethylamine, palmitamidoethyldimethylamine,

behenamidopropyldimethylamine, behenamidopropyldiethylamine,

behenamidoethyldiethylamine, behenamidoethyldimethylamine,

arachidamidopropyldimethylamine, arachidamidopropyldiethylamine,

arachidamidoethyldiethylamine, arachidamidoethyldimethylamine, and

diethylaminoethylstearamide.

Also useful are dimethylstearamine, dimethylsoyamine, soyamine, myristylamine, tridecylamine, ethylstearylamine, N-tallowpropane diamine, ethoxylated (with 5 moles of ethylene oxide) stearylamine, dihydroxyethylstearylamine, and arachidyl behenylamine.

Particularly preferred is stearamidopropyldimethylamine.

Mixtures of any of the foregoing materials may also be suitable.

The acid used to provide the cationic species can be 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. In general, a sufficient amount of acid is added to neutralise the amidoamine compound and to adjust the final pH of the composition to within a range of from about 2.5 to about 6, preferably in a pH range of from about 3 to about 5. The molar ratio of protonatable amine groups to H+ from the acid is preferably from about 1 :0.3 to 1 :1 .2, and more preferably from about 1 :0.5 to about 1 :1 .1 .

Mixtures of any of the above-described cationic surfactants may also be suitable.

The level of cationic surfactant (III) will generally range from 0.01 to 10%, more preferably 0.02 to 7.5%, most preferably 0.05 to 5% (by weight based on the total weight of the composition).

The cationic surfactant (III) provides improved robustness of the conditioning gel network, leading to improved conditioning benefit in the presence of non-cationic cleansing ingredients such as the cleansing anionic surfactant as described above.

The difference in carbon chain length between the cleansing anionic surfactant as described above and the gel network anionic surfactant (II) as described above improves stability of the conditioning gel network and maintains its integrity in the shampoo composition.

Particularly preferred conditioning gel networks for inclusion in the shampoo composition of the invention are formed from: (I) fatty material of general formula R-OH, in which R is a linear saturated

hydrocarbon chain having from 16 to 22 carbon atoms;

(II) gel network anionic surfactant of general formula R-O-SO3^"M⁺ in which R is a straight chain alkyl group having 16 to 22 carbon atoms and M is sodium, potassium, monoethanolammonium or triethanolammonium, or a mixture thereof, and (III) cationic surfactant of general formula [N(R¹)(CH₃)₃]+ (X)- in which R¹ is a Ci6 to C22 saturated alkyl chain, and X is chloride or bromide.

In such conditioning gel networks as defined above, it is particularly preferred that the R groups in the fatty material (I) and the R groups in the gel network anionic surfactant (II) have an average carbon chain length which differs by no more than about 4 carbon atoms. It is also particularly preferred that the R groups in the gel network anionic surfactant (II) and the R¹ groups in the cationic surfactant (III) have an average carbon chain length which differs by no more than about 4 carbon atoms. This assists in maintaining stability of the gel network. It is also

particularly preferred that the R groups in the fatty material (I) and the R¹ groups in the cationic surfactant (III) have an average carbon chain length which differs by no more than 4 carbon atoms. Preferably the average carbon chain length differs by no more than 2 carbon atoms. More preferably the average carbon chain length is the same. This assists in maintaining stability of the gel network.

In conditioning gel networks for inclusion in the composition of the invention, the weight ratio between the fatty material (I) and the gel network anionic surfactant (II) generally ranges from 0.1 :1 to 100:1 , preferably from 1 .2:1 to 50:1 , more preferably from 1 .5:1 to 10:1 and most preferably around 2:1 . The weight ratio between the gel network anionic surfactant (II) and the cationic surfactant (III) in conditioning gel networks for inclusion in the composition of the invention generally ranges from 6:1 to 20:1 and preferably ranges from 9:1 to 13:1 . The conditioning gel network is stabilized in the aqueous continuous phase by the inclusion of one or more osmolytes.

The term "osmolyte" refers to an agent that affects osmosis. Suitable osmolytes in the context of the present invention are capable of increasing the thermal stability of the conditioning gel network in the conditioning shampoo composition of the invention, generally by maintaining the osmotic balance between the conditioning gel network and the aqueous continuous phase. In a typical shampoo environment, this balance can become disrupted by the presence of inorganic ions (sodium chloride, potassium chloride or other metallic salts) as well as rheology modifiers such as acrylic polymers and polyhydric alcohols.

Therefore, an osmotic stress can exist between the gel and the shampoo environment.

Osmolytes are typically low molecular weight organic compounds with no net charge. These include zwitterionic compounds (compounds that contain charged species, but whose overall charge is zero due to equal numbers of positive and negative charges). "Low molecular weight" encompasses any compound having a molecular weight less than about 1000 g/mol. In essence, there are three major chemical classes of osmolyte: polyhydroxy compounds such as polyhydric alcohols and sugars, methyl amines, and certain amino acids.

Preferred osmolytes for use in the invention may be selected from low molecular weight polyhydric alcohols and sugars. More preferably the polyhydric alcohols and sugars have a molecular weight ranging from about 50 to about 750 g/mol, most preferably from about 75 to about 500 g/mol.

Specific examples of such preferred osmolytes for use in the invention include polyhydric alcohols such as sorbitol, inositol, mannitol, xylitol and glycerol; and sugars such as trehalose, lactose, sucrose, glucose, galactose, maltose, mannose and fructose.

Particularly preferred osmolytes for use in the invention are glycerol, sorbitol and most preferably trehalose. Mixtures of any of the above-described osmolytes may also be suitable.

The level of osmolyte will depend on the particular type chosen, but generally ranges from 0.01 to 5% by total weight osmolyte. When the osmolyte is a low molecular weight polyhydric alcohols or sugar (as described above), the amount of low molecular weight polyhydric alcohol or sugar in compositions of the invention suitably ranges from 0.01 to 5%, more preferably from 0.05 to 2.5% and most preferably from 0.5 to 2% (by total weight low molecular weight polyhydric alcohol or sugar based on the total weight of the composition).

Optional Ingredients

Optionally, a composition of the invention may contain further ingredients as described below to enhance performance and/or consumer acceptability.

A preferred additional component in conditioning shampoo compositions according to the invention is silicone oil. When used, silicone oil is typically present as emulsified droplets having a mean droplet diameter (D3,2) of 4 micrometres or less. Preferably the mean droplet diameter (D3,2) is 1 micrometre or less, more preferably 0.5 micrometre or less, and most preferably 0.25 micrometre or less. A suitable method for measuring the mean droplet diameter (D3,2) is by laser light scattering using an instrument such as a Malvern Mastersizer.

Preferably the silicone oil is non-volatile, meaning that it has a vapour pressure of less than 1000 Pa at 25°C. Suitable silicone oils are polydiorganosiloxanes, in particular

polydimethylsiloxanes (dimethicones), polydimethyl siloxanes having hydroxyl end groups (dimethiconols), and amino-functional polydimethylsiloxanes

(amodimethicones).

Suitable silicones preferably have a molecular weight of greater than 100,000 and more preferably a molecular weight of greater than 250,000.

Suitable silicones preferably have a kinematic viscosity of greater than 50,000 cS (mm2.s-1 ) and more preferably a kinematic viscosity of greater than 500,000 cS (mm2.s-1 ). Silicone oil kinematic viscosities as referred to in this specification are measured at 25°C and can be measured by means of a glass capillary viscometer as set out further in Dow Corning Corporate Test Method CTM004 July 20, 1970. Suitable silicones for use in compositions of the invention are available as preformed silicone emulsions from suppliers such as Dow Corning and GE Silicones. The use of such pre-formed silicone emulsions is preferred for ease of processing and control of silicone particle size. Such pre-formed silicone emulsions will typically additionally comprise a suitable emulsifier, and may be prepared by a chemical emulsification process such as emulsion polymerisation, or by

mechanical emulsification using a high shear mixer. Pre-formed silicone emulsions having a mean droplet diameter (D3,2) of less than 0.15 micrometers are generally termed microemulsions. Examples of suitable pre-formed silicone emulsions include emulsions DC2-1766, DC2-1784, DC-1785, DC-1786, DC-1788, DC-1310, DC-7123 and

microemulsions DC2-1865 and DC2-1870, all available from Dow Corning. These are all emulsions/microemulsions of dimethiconol. Also suitable are

amodimethicone emulsions such as DC939 (from Dow Corning) and SME253 (from GE Silicones). Mixtures of any of the above described silicone emulsions may also be used.

The amount of silicone oil in compositions of the invention may suitably range from 0.05 to 10%, preferably from 0.2 to 8% (by total weight silicone oil based on the total weight of the composition).

A preferred additional component in conditioning shampoo compositions according to the invention is a cationic polymer. Such polymers may enhance the delivery of conditioning agents and thereby improve the conditioning benefits obtained.

Cationic polymers typically contain cationic nitrogen-containing groups such as quaternary ammonium or protonated amino groups. The cationic protonated amines can be primary, secondary, or tertiary amines (preferably secondary or tertiary). The average molecular weight of the cationic polymer is preferably from 5,000 to 10 million. The cationic polymer preferably has a cationic charge density of from 0.2 meq/gm to 7 meq/gm. The cationic nitrogen-containing moiety of the cationic polymer is generally present as a substituent on all, or more typically on some, of the repeat units thereof. The cationic polymer may be a homo-polymer or co-polymer of quaternary ammonium or cationic amine-substituted repeat units, optionally in combination with non-cationic repeat units. Particularly suitable cationic polymers for use in the composition include polysaccharide polymers, such as cationic cellulose derivatives, cationic starch derivatives, and cationic guar gum

derivatives.

A particularly suitable type of cationic polysaccharide polymer that can be used is a cationic guar gum derivative, such as guar hydroxypropyltrimethylammonium chloride (commercially available from Rhodia® in their JAGUAR® trademark series). Examples of such materials are JAGUAR ® C13S, JAGUAR ® C14, JAGUAR® C15 and JAGUAR ® C17.

The total amount of cationic polymer in the composition is preferably from 0.05% to 2% and more preferably from 0.1 to 0.5% by weight based on the total weight of the composition.

An amphoteric surfactant is a preferred additional ingredient in compositions of the invention. Suitable amphoteric surfactants are betaines, such as those having the general formula R(CH3)2N⁺CH₂COO^", where R is an alkyl or alkylamidoalkyl group, the alkyl group preferably having 10 to 16 carbon atoms. Particularly suitable betaines are oleyl betaine, caprylamidopropyl betaine, lauramidopropyl betaine, isostearylamidopropyl betaine, and cocoamidopropyl betaine.

When included, the total level of amphoteric surfactant is preferably from 0.1 % to 20%, more preferably from 1 % to 10%, and most preferably from 1 % to 5% by weight based on the total weight of the composition .

Preferably, an aqueous shampoo composition of the invention further comprises a suspending agent. Suitable suspending agents are selected from polyacrylic acids, cross-linked polymers of acrylic acid, copolymers of acrylic acid with a hydrophobic monomer, copolymers of carboxylic acid-containing monomers and acrylic esters, cross-linked copolymers of acrylic acid and acrylate esters, heteropolysaccharide gums and crystalline long chain acyl derivatives. Mixtures of any of the above suspending agents may be used. Preferred is a mixture of cross-linked polymer of acrylic acid and crystalline long chain acyl derivative.

Suspending agent will generally be present in a shampoo composition of the invention at levels of from 0.1 to 10%, preferably from 0.5 to 6%, more preferably from 0.9 to 4% by total weight of suspending agent based on the total weight of the composition.

Compositions according to the invention may contain other minor ingredients which are customarily included in conditioning shampoos, such as fragrance, dyes and pigments, pH adjusting agents, pearlescers or opacifiers, viscosity modifiers, and preservatives or antimicrobials. 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 5% by weight based on the total weight of the composition.

Process

The invention also provides a process of manufacturing a conditioning shampoo composition having the ingredients as specified above, the process comprising the steps of: i) forming a conditioning gel network of lamellar or vesicular solid crystalline fatty material and including one or more osmolytes;

ii) dispersing the conditioning gel network so obtained into an aqueous

continuous phase including cleansing surfactant.

In a preferred process according to the invention, an aqueous gel phase premix is prepared which comprises a conditioning gel network of lamellar or vesicular solid crystalline fatty material and including one or more osmolytes. This premix is then combined with the remaining shampoo ingredients as described above to form the final composition. The aqueous gel phase premix is generally prepared by heating water in a mixing vessel, and dispersing the ingredients which form the conditioning gel network into the heated water, together with the one or more osmolytes. Typically the aqueous gel phase premix will comprise:

(a) from 50 to 90%, preferably from 60 to 80% (by weight based on the total weight of the gel phase premix) of water;

(b) from 5 to 30%, preferably from 10 to 20% (by weight based on the total weight of the gel phase premix) of a fatty material (I) as further described above;

(c) from 2 to 15%, preferably from 5 to 10% (by weight based on the total weight of the gel phase premix) of a gel network anionic surfactant (II) as further described above;

(d) from 0.1 to 5%, preferably from 0.5 to 2.0% (by weight based on the total weight of the gel phase premix) of a cationic surfactant (III) as further described above, and

(e) from 2 to 15%, preferably from 5 to 10% (by weight based on the total weight of the gel phase premix) of osmolyte as further described above.

Typically the water (a) is heated (usually to about 70 or 80°C or above) in a mixing vessel, followed by the addition of the remaining gel phase premix ingredients (b) to (e). The osmolyte (e) may be added to mixing vessel before or after the gel network anionic surfactant (c).

The resulting mixture is stirred at high speed until a uniform dispersion is obtained and then cooled, usually to about 55 or 45°C or below.

To form the final conditioning shampoo composition of the invention, from 5 to 30%, preferably from 10 to 20% (by weight based on the total weight of the final composition) of cooled gel phase premix is added to an aqueous continuous phase including cleansing surfactant as further described above and the remaining shampoo ingredients. The resulting mixture is stirred at moderate speed until a uniform dispersion is obtained.

Mode of Use The composition of the invention is primarily intended for topical application to the body, preferably the hair of a human subject.

Most preferably the composition of the invention is topically applied to the hair of a human subject and then massaged into the hair and scalp. The composition is then rinsed off the hair and scalp with water prior to drying the hair.

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

EXAMPLES

Gel phase pre-mixes were prepared having ingredients as shown in Table 1 below.

Table 1

To prepare the gel phase pre-mixes, the water was heated to about 80°C in a side pot. The remaining ingredients were added with high speed stirring. When a uniform dispersion was obtained, the mixture was cooled down to about 45°C with the same speed stirring.

The above gel phase pre-mixes were combined with conditioning shampoo ingredients to form conditioning shampoo compositions. The ingredients are shown in Table 2 below. Examples 1 to 3 represent compositions according to the invention. Example A is a comparative example (not according to the invention). Table 2

Ingredient Example 1 Example 2 Example 3 Example A

(% w/w) (% w/w) (%w/w) (%w/w)

Sodium laureth sulphate (25% a.i.) 48.73 48.73 48.73 48.73

Cocamidopropyl betaine (30% a.i.) 5.40 5.40 5.40 5.40

Guar hydroxypropyltrimonium 0.20 0.20 0.20 0.20 chloride

Dimethiconol emulsion (50% a.i.) 6.00 6.00 6.00 6.00

Ethylene glycol distearate (35% a.i.) 2.50 2.50 2.50 2.50

Gel Phase Pre-mix 1 15.00

Gel Phase Pre-mix 2 15.00

Gel Phase Pre-mix 3 15.00

Gel Phase Pre-mix 4 15.00

Ti0₂ coated mica 0.20 0.20 0.20 0.20

Disodium EDTA 0.10 0.10 0.10 0.10

Polypropylene glycol 0.40 0.40 0.40 0.40

Carbomer 0.40 0.40 0.40 0.40

Sodium hydroxide 0.37 0.37 0.37 0.37

Sodium chloride 1.00 1.00 1.00 1.00

Water, perfume, preservatives q.s.to 100 q.s.to 100 q.s.to 100 q.s.to 100

The climatic stability of the above compositions was evaluated by DSC scanning. The results are shown in Table 3 below and demonstrate that Examples 1 to 3 according to the invention have a higher temperature stability than Example A.

Decomposition enthalpy (Joules/g) Example 1 Example 2 Example 3 Example A

(% w/w) (% w/w) (%w/w) (%w/w)

Storage temperature: 40 °C

4.24 2.99 3.14 1.95

Cycle: 24 hours; constant temperature

Storage temperature: 37 °C

3.75 3.01 2.35 2.52

Cycle: 1 week; constant temperature

Storage temperature: 25°C

Cycle: 1 week; constant temperature 4.1 1 3.48 3.77 3.08

Claims

1 . A conditioning shampoo composition having: an aqueous continuous phase including cleansing surfactant, and a conditioning gel network which is dispersed in the aqueous continuous phase; in which the conditioning gel network is formed from lamellar or vesicular solid crystalline fatty material; and characterized in that the conditioning gel network is stabilized in the aqueous continuous phase by the inclusion of one or more osmolytes.

A composition according to claim 1 , in which the conditioning gel network has no overall charge or is anionic and is formed from:

(I) fatty material,

(II) anionic surfactant comprising an alkyl group with from 16 to 30 carbons ("gel network anionic surfactant"), and

(III) cationic surfactant.

A composition according to claim 2, in which the fatty material (I) has the general formula R-OH, in which R is a linear saturated hydrocarbon chain having from 16 to 22 carbon atoms; the gel network anionic surfactant (II) has the general formula R-O-SO₃ ^"M⁺ in which R is a straight chain alkyl group having 16 to 22 carbon atoms and M is sodium, potassium, monoethanolammonium or triethanolammonium, or a mixture thereof, and the cationic surfactant (III) has the general formula [N(R¹)(CH₃)₃]+ (X)- in which R¹ is a Ci₆ to C₂2 saturated alkyl chain, and X is chloride or bromide.

4. A composition according to any preceding claim, in which the one or more osmolytes are selected from polyhydric alcohols and sugars having a molecular weight ranging from 50 to 750 g/mol.

5. A composition according to claim 4, in which the one or more

osmolytes are selected from glycerol, sorbitol and trehalose.

6. A composition according to any preceding claim, in which the cleansing surfactant is an anionic surfactant selected from sodium, potassium, ammonium or ethanolamine salts of C-m to Ci₂ alkyl sulphates and C-m to C-I2 alkyl ether sulphates.

7. A process of manufacturing a conditioning shampoo composition

according to claim 1 , the process comprising the steps of: i) forming a conditioning gel network of lamellar or vesicular solid crystalline fatty material and including one or more osmolytes;

ii) dispersing the conditioning gel network so obtained into an aqueous

continuous phase including cleansing surfactant.