EP3585350A1

EP3585350A1 - Topical composition with a firm texture

Info

Publication number: EP3585350A1
Application number: EP18703034.1A
Authority: EP
Inventors: Guillaume Bernard LAURENT; Szilvia MESAROS
Original assignee: DSM IP Assets BV
Current assignee: DSM IP Assets BV
Priority date: 2017-02-24
Filing date: 2018-02-09
Publication date: 2020-01-01
Also published as: CN110381913A; WO2018153701A1

Abstract

The present invention relates to a method for preparing a topical composition comprising hydroxystearic acid and to compositions prepared according to said method. The compositions are easily spreadable despite of having a firm texture. The composition may be firm enough to be formed in the shape of a cosmetic stick. 10-hydroxystearic acid and 12- hydroxystearic acid are the preferred hydroxystearic acids.

Description

TOPICAL COMPOSITION WITH A FIRM TEXTURE

Technical field The present invention relates to an easily spreadable topical composition.

For storage, transportation and sale of topical compositions, pots with a removable, sometimes rotatable lid are used. Pots as used in the cosmetic and pharmaceutical industry are often sealed with a peelable liner made of aluminum, plastic or paper before attaching the lid. Direct contact of the topical composition with the peelable liner is undesired but difficult to avoid in case the topical composition is flowable.

Background of the invention

Typically, cosmetic pots are made of glass or plastic. They often have a diameter of less than 20 cm. Such pots are mostly used to store, transport or sell compositions for topical use on consumer's skin. An example of such a pot is shown in FIGU RE 1.

I n some cases, the topical composition in the pot is a solid wax. I n other cases, however, the topical composition is a flowable composition. At room temperature, most skin creams are at least to a certain extent flowable.

I n case of a solid composition such as a wax, there is no risk of spilling the composition on the inner side of the peelable liner. However, in case of a flowable composition, the inner side of the peelable liner may come in contact with the flowable composition due to movements during transportation.

The same issue applies to the inner side of a rotatable lid: Once the consumer has removed the peelable liner, the flowable composition in the pot may come in contact with the inner side of the lid. This is clearly undesirable and is often considered as a mess. If the pot is not properly closed after use, it may even happen that the consumer's handbag is stained with the flowable composition. Whereas these issues can be avoided by using non-flowable compositions, such non- flowable compositions often have an unpleasant, cosmetically unacceptable texture and are not easily spreadable. Many non-flowable compositions of the prior art are not suitable for rubbing gently into the skin of a consumer or patient. An inner seal as suggested by EP 1 391 162 does not solve the problem underlying the present invention as said inner seal is not protected from being soiled by the flowable composition.

Summary of the invention The problem to be solved by the present invention is avoiding the contact of an easily spreadable topical composition filled in a cosmetic pot with the pot's lid and/or peelable liner during transportation.

The problem is solved by providing a composition which has an excellent

spreadability on the skin despite of having a firm texture. The composition comprises water, at least one lipophilic ingredient and hydroxystearic acid. It is thick in appearance and as such, the composition is firm enough to avoid the contact with the lid and/or peelable liner of a pot during transportation. Surprisingly, the composition can be easily spread onto the skin despite of its firmness.

Compositions comprising water and hydroxystearic acid have been discussed in the prior art. US 9,539,190 discloses non-solid skin conditioning compositions comprising 12-hydroxystearic acid which are suitable for spreading on the skin. A skin conditioning composition which is easily spreadable despite of having a firm texture is not disclosed in US 9,539,190.

Surprisingly, the texture of compositions comprising water, at least one lipophilic ingredient and hydroxystearic acid depends on the manufacturing process. A composition prepared according to the present invention is a yield-pseudoplastic fluid. Such composition is non-flowable unless yield stress is exceeded.

Compositions according to the invention are preferably prepared by a method comprising the steps: allow an emulsion comprising water, hydroxystearic acid, at least one lipophilic ingredient and preferably at least one emulsifier to cool down under stirring;

stop stirring the emulsion when the mixture has cooled down to a temperature between 35°C and 70°C; and

allow the emulsion to cool down to room temperature without stirring.

If stirring is not stopped before the emulsion reaches room temperature, the final composition does not have a firm texture, i.e. is not a yield-pseudoplastic fluid according to the invention. The texture of a composition can be analyzed by a texture analyzer, as known in the art. In a penetration test as described in WO 2014/009079, a plunger is forced into a composition and the force required for penetration of the composition is plotted against the distance (or time) of penetration into the composition at a predetermined speed to a pre-determined depth of penetration. A composition has a breaking point if the maximum force is observed before reaching the maximum distance (depth) of penetration. The occurrence of a breaking point typically relates to the irreversible deformation of the structure of a composition. In case of a flowable composition such as a paste, maximum force is observed at the maximum distance (depth) of penetration. Such composition does not have a breaking point.

When testing the penetration resistance of a composition prepared according to the present invention, a breaking point is observed, suggesting the deformation of the composition's internal structure. The force at the breaking point, corresponding to the firmness of the composition, is preferably at least 0.1 kg. No breaking point is observed if stirring is not stopped during preparation of the composition.

The hydroxyl group of hydroxystearic acid might be at different positions. However, the preferred hydroxystearic acid is 10-hydroxystearic acid. Compositions comprising 10-hydroxystearic acid have an increased firmness but are nonetheless easily spreadable. An increase of the composition's firmness avoids contact of the composition with the pot's closure even if transportation is rough. If an increased amount of hydroxystearic acid is used, the composition of the invention may be hard enough to produce a cosmetic stick. When applied to the skin, the part of the composition forming the top of the stick changes its

texture/hardness, becomes spreadable and can be easily applied to the skin. A cosmetic stick made of the composition of the invention is an alternative, surprising solution to avoid staining of the consumer's handbag due to movements during transportation.

Detailed description of the invention The composition according the invention comprises water, hydroxystearic acid, at least one lipophilic ingredient and preferably at least one emulsifier.

Preferably, non-ionic emulsifiers are used. Particularly good results are achieved when cetearyl glucoside is used. Anionic emulsifiers are not preferred. In the context of the present invention and for the sake of clarity, hydroxystearic acid is not considered as emulsifier, i.e. hydroxystearic acid is an ingredient sui generis.

However, since hydroxystearic acid may facilitate the provision of an emulsion, the addition of an emulsifier is optional.

In the context of the present invention, a "lipophilic ingredient" is able to dissolve in fats, oils, lipids and/or non-polar solvents such as hexane or toluene. In the context of the present invention and for the sake of clarity, hydroxystearic acid is not considered as lipophilic ingredient, i.e. hydroxystearic acid is an ingredient sui generis.

The lipophilic ingredient may be a cosmetically acceptable oil. Suitable oils may be volatile or non-volatile, or a mixture of both. Suitable volatile oils include, but are not limited to straight or branched chain hydrocarbons having from 8-20 carbon atoms, such as decane, dodecane, tridecane, tetradecane, and Cs-2o isoparaffins. Nonvolatile oils include, but are not limited to, vegetable oils, such as coconut oil, jojoba oil, corn oil, sunflower oil, palm oil, soybean oil, almond oil, argan oil, carboxylic acid esters such as isostearyl neopentanoate, cetyl octanoate, cetyl ricinoleate, octyl palmitate, dioctyl malate, coco-caprylate, coco-caprylate/ca prate, decyl isostearate, myristyl myristate, C12-15 alkyl benzoate, animal oils such as lanolin and lanolin derivatives, tallow, mink oil or cholesterol; glyceryl esters, such as glyceryl stearate, glyceryl dioleate, glyceryl distearate, glyceryl linoleate, glyceryl myristate;

caprylic/capric triglyceride; and non-volatile hydrocarbons, such as isoparaffins, squalane, or petrolatum. A further suitable group of lipophilic ingredients are oil soluble sunscreen agents.

Whereas the hydroxyl group of hydroxystearic acid may be at different positions, 9-hydroxystearic acid, 10-hydroxystearic acid, 11-hydroxystearic acid, 12-hydroxystearic acid, 13-hydroxystearic acid or a mixture thereof are preferred. Particularly preferred are 10-hydroxystearic acid, 12-hydroxystearic acid and a mixture thereof. 10-hydroxystearic acid is the most preferred hydroxystearic acid. Both enantiomers of 10-hydroxystearic acid may be used according to the invention, but the preferred enantiomeric form of 10-hydroxystearic acid is (R)-lO-hydroxystearic acid.

In the composition, hydroxystearic acid may be partially deprotonated. Thus, in the context of the present invention, the term hydroxystearic acid includes the conjugate base of the free acid.

In one embodiment of the invention, the composition comprises hydroxystearic acid in an amount of less than 3 weight%, preferably in an amount of less than 2 weight%, and most preferably in an amount of less than 1.5 weight%, wherein the minimal amount of hydroxystearic acid is preferably 0.1 weight%, more preferably 0.2 weight% and most preferably 0.5 weight%. The most preferred range is from 0.5 weight% to 1.5 weight% hydroxystearic acid. For producing a stick, higher amounts of hydroxystearic acid might be necessary. Thus, in one embodiment of the invention, the composition comprises hydroxystearic acid in an amount of at least 2 weight% and preferably in an amount of at least 3 weight%, wherein the composition comprises preferably less than 10 weight% of hydroxystearic acid. In the context of the present invention, "weight%" refers to the amount based on the total weight of the composition.

One embodiment of the invention relates to the use of hydroxystearic acid for preparing a composition with a firmness of at least 0.1 kg. The required firmness is achieved if the composition comprising water, at least one lipophilic ingredient and hydroxystearic acid is prepared according to the invention.

Methods for preparing emulsions are well known to the person skilled in the art. These methods encompass homogenization of an oil phase and of a water phase under high shear stress at elevated temperature. After homogenization, the mixture is allowed to cool down or is cooled down by a cooling medium such as cold water. During the cool down phase, the mixture is agitated e.g. by stirring at low shear. Said stirring is done for various reasons (e.g. to accelerate cooling, to cool down the inner parts of a large batch etc.). This is where the method of the invention differs from the state of the art. According to the invention, stirring must be stopped before the homogenized mixture (i.e. the emulsion) reaches room temperature. In a preferred method, the hot mixture is filled into smaller containers (such as cosmetic pots or canisters) in order to cool down to room temperature in said containers. After having reached room temperature, the cosmetic pots etc. are ready to be sold. If stirring is not stopped before the homogenized mixture reaches room temperature, the final composition is not a yield-pseudoplastic fluid with the required firm texture.

One method for preparing a composition comprising water, at least one lipophilic ingredient and hydroxystearic acid comprises the steps:

mix ingredients of phase A and heat up to more than 70°C, said phase A comprising water and any other optional ingredient;

mix ingredients of phase B and heat up to more than 70°C, said phase B comprising hydroxystearic acid, at least one lipophilic ingredient and preferably at least one emulsifier;

mix both phases, preferably by adding phase B to phase A, and homogenize the mixture in order to get an emulsion; stop stirring of the emulsion before the emulsion reaches room temperature, wherein hydroxystearic acid is preferably 10-hydroxystearic acid, 12-hydroxystearic acid or a mixture thereof.

For homogenization, high shear is applied (e.g. Ultra Turrax^®; 13500 rpm). The aim of homogenization is providing an emulsion of phase A and phase B.

Another method for preparing a composition comprising water, at least one lipophilic ingredient and hydroxystearic acid comprises the steps:

prepare an emulsion comprising water, at least one lipophilic ingredient, hydroxystearic acid and preferably at least one emulsifier;

- fill the emulsion into containers before the emulsion has cooled down to room temperature,

allow the emulsion to cool down to room temperature in said containers without stirring

wherein hydroxystearic acid is preferably 10-hydroxystearic acid, 12-hydroxystearic acid or a mixture thereof. As explained above, the emulsion is prepared at elevated temperature under vigorous agitation.

Typically, the containers are cosmetics pots which can be used for selling the composition. In order to manufacture a stick, the hot emulsion is preferably filled in a canister with a dome-shaped end, a cone-shaped end or a flat end. The present invention also relates to a composition prepared according the described method. One embodiment of the invention relates to a composition prepared by a method comprising the steps:

allow an emulsion comprising water, hydroxystearic acid, at least one lipophilic ingredient and preferably at least one emulsifier to cool down under agitation, such as stirring;

stop stirring the emulsion when the emulsion has cooled down to a temperature between 35°C and 70°C; and

allow the emulsion to cool down to room temperature without stirring wherein hydroxystearic acid is preferably 10-hydroxystearic acid, 12-hydroxystearic acid or a mixture thereof. In this embodiment, stirring refers preferably to low shear stirring (i.e. less than 300 rpm).

A preferred embodiment of the invention relates to a composition prepared by a method comprising the steps:

prepare an emulsion comprising at least 70 weight% water, between 0.1 and 3 weight% hydroxystearic acid, at least one lipophilic ingredient and preferably at least one emulsifier;

fill the emulsion into containers (such as pots or canisters) before the emulsion has cooled down to room temperature; and

allow the emulsion to cool down to room temperature in said containers without stirring,

wherein hydroxystearic acid is preferably 10-hydroxystearic acid, 12-hydroxystearic acid or a mixture thereof.

Spreadability of the composition

Despite the fact that the composition according to the invention is resistant to flow and has a firm texture, it can be spread with ease on the skin or any other surface. This unexpected change of texture and the cooling effect which goes along with the change of texture is highly appreciated by consumers of cosmetic products.

Without wishing to be bound to any particular theory, it is believed that the texture of the composition is facilitated by a three-dimensional network. If said three- dimensional network is destroyed (e.g. by spreading/stirring), the composition becomes fluid. During spreading, a cooling effect is sensed on the skin, possibly because of the destruction of the network requires energy.

In case of a Newtonian fluid, the relation between the shear stress [Pa] and the shear rate [1/s] is linear: the higher the shear stress, the higher the shear rate. The constant of proportionality is the coefficient of viscosity. High viscosity liquids need more shear stress to flow whereas low viscosity systems require less shear stress to flow.

Curves in a rheogram, showing the shear stress on the y-axis and showing the shear rate on the x-axis are referred to as flow curves. Flow curves of Newtonian fluids are linear and pass through the origin. Flow curves of non-Newtonian fluids are nonlinear and/or do not pass through the origin.

Some non-Newtonian fluids show visco-plastic fluid behavior, i.e. a yield stress must be exceeded for the composition to flow. If the externally applied stress is less than the yield stress, the composition is non-flowable, i.e. behaves like an elastic solid or a rigid body. If the externally applied stress is more than the yield stress, the structure breaks down and the composition begins to flow.

If the flow curve of the composition is approximately linear once the applied stress is more than the yield stress, the composition is called a Bingham plastic fluid. If the composition shows shear-thinning once the applied stress is more than the yield stress, the composition is referred to as yield-pseudoplastic fluid. The corresponding flow curve is not linear; the curve's slope decreases as the share rate is increased. A more detailed description of these terms can be found for example in "Non- Newtonian Fluids: An Introduction" by Chhabra, Rajendra P., Rheology of Complex Fluids, 2010, p3-34, 32p. The composition according to the invention is a yield-pseudoplastic fluid. In the context of the present invention, "yield-pseudoplastic fluid" refers to a composition (i) wherein a yield stress must be exceeded for the composition to flow and (ii) wherein the slope of the shear stress versus shear rate curve of the composition decreases to approximate zero at a shear rate of approximately 450/s. This is to be understood as a qualitative description of the flow curve and has to be seen in contrast to the flow curve of a Bingham plastic fluid, said flow curve becoming approximately linear as the shear stress is increased (cf. FIGU RES 2, 3, and 4).

In a preferred embodiment of the invention, the composition is a yield-pseudoplastic fluid comprising:

· at least 70 weight% water, • between 0.1 weight% and 3 weight% hydroxystearic acid,

• at least one lipophilic ingredient, and

• preferably at least one emulsifier,

In the context of the present invention, all rheological measurements are done at 25°C, using an AR 550 Advanced Rheometer with a plate SST ST 40mm (N° 984856). The following test parameters are chosen:

Shear rate ramp: 0-1000 · 1/s in 3 minutes

Measuring points: 60

Quantity of composition used for the measurement: 0.8-lg

Preferably, the difference between the shear stress of the composition at a shear rate of 400/s and the shear stress of the same composition at a shear rate of 600/s is less than 20 Pa, more preferably less than 10 Pa and most preferably less than 5 Pa. In the context of the present invention, "difference" refers to the absolute value, i.e. the non-negative value without regard to its sign.

In another embodiment of the invention, the composition is a yield-pseudoplastic fluid, wherein the difference between the shear stress of the composition at a shear rate of 400/s and the shear stress of the same composition at a shear rate of 800/s is less than 40 Pa, preferably less than 30 Pa and most preferably less than 20 Pa. This is referred to as a curve having a plateau.

In yet another embodiment of the invention, the composition is a yield- pseudoplastic fluid, wherein the difference between the shear stress of the composition at a shear rate of 200/s and the shear stress of the same composition at a shear rate of 800/s is less than 80 Pa, preferably less than 70 Pa and most preferably less than 60 Pa.

In contrast to the yield-pseudoplastic fluid according to the invention, the plot of shear stress versus shear rate of a Bingham plastic fluid approximates a straight line with a constant slope being > 0, provided a shear rate of 700/s is not exceeded. In order to get the yield-pseudoplastic fluid according to the invention instead of a Bingham plastic fluid, the manufacturing process according to the invention must be followed. Thus, the discussed rheological properties do not depend on the specific ingredients of the composition, provided the composition comprises a suitable hydroxystearic acid. If stearic acid instead of hydroxystearic acid is used, the resulting composition is a Bingham plastic fluid as describe above, even if the manufacturing process according to the invention is used.

At very low shear stress, the composition of the invention does not flow until the shear stress reaches a critical transition point. The stress at this point is known as yield stress. At stresses below the yield stress, the system acts like a more or less elastic solid.

A relatively high yield stress helps avoiding the contact of the composition filled in cosmetic pot with the pot's lid and/or peelable liner during transportation. In one embodiment of the invention, hydroxystearic acid is used to increase the yield stress of a yield-pseudoplastic fluid. Surprisingly, yield-pseudoplastic fluids comprising less than 10 weight% of hydroxystearic acid are easily spreadable, regardless of their yield stress.

Penetration resistance in constant velocity conditions Texture attributes such as firmness may be mechanically tested, e.g. by using the engineering concept of penetration resistance.

Penetration resistance testing involves the insertion of a probe (e.g. a metallic cylinder) into a composition with a certain firmness. The test is stopped at a predetermined depth of penetration before the probe reaches the plate holding the composition to be tested. The results of such testing can determine changes of the texture of a composition whose firmness is a measure of a quality.

The penetration resistance test is conducted at constant velocity, i.e. with a predetermined speed of the probe. The speed of the probe (i.e. the penetration rate) is expressed in [mm/s]. In constant velocity conditions, time corresponds to the distance of penetration into the composition. The force necessary to maintain the pre-determined speed depends on the texture of the composition and is expressed in [kg].

In the context of the present invention, all penetration resistance tests are done at room temperature, using TAXT plus Texture Analyzer of the company Stable Micro Systems. As a probe, a metallic cylinder having a diameter of 2 cm is used. The tip of said probe is flat. A pot having a diameter of 5 cm is filled with 1 cm of the composition to be tested. The following test parameters are chosen:

pre-determined speed of the probe: 2 mm/s

pre-determined depth of penetration: 5 mm

In constant velocity conditions and when testing a paste or a very elastic gel, the value of force to maintain the predetermined speed of the probe usually increases over time and reaches a maximum at the point of deepest penetration.

In case of the composition according to the invention, however, the maximum force is measured before the pre-determined depth of penetration is reached. This point is called breaking point. The breaking point may be the peak of a shoulder.

If the maximum force occurs when the probe reaches the pre-determined depth of penetration (i.e. at the point of deepest penetration), the composition does not have a breaking point. In the context of the present invention, a composition has a "breaking point" if the maximum force occurs before the probe reaches a depth of 5 mm and before the probe reaches the plate holding the composition to be tested, wherein a probe is forced into said composition at a pre-determined speed at room temperature and wherein the force necessary to maintain a pre-determined speed is measured. The above mentioned test conditions apply (room temperature, metallic cylinder having a diameter of 2 cm, speed of the probe: 2 mm/s).

Thus, the pre-determined depth of penetration is 5 mm. And therefore, in the context to the present invention, any maximum force occurring at a penetration depth of 5 mm or more than 5 mm is not considered as a breaking point. One embodiment of the invention relates to a composition comprising water, at least one lipophilic ingredient and hydroxystearic acid, wherein said composition has a breaking point when penetration resistance is tested.

The person skilled in the art is familiar with the concept of breaking points. WO 2014/009079 discloses semi-solid food gel which shows a breaking point in the first penetration cycle of two consecutive penetrations.

According to the invention, a breaking point is observed in the first cycle of the penetration test only. If the probe is withdrawn to perform a second cycle, the maximum force is observed at the maximum depth of penetration. A breaking point occurring only in the first of two consecutive penetrations indicates the irreversible deformation of the composition's structure during the first cycle.

Without wishing to be bound to any particular theory, it is believed that the texture of the composition according to the invention is facilitated by a three-dimensional network. At the beginning of the penetration test, relatively high force is needed to break/destroy said network. Therefore, the maximum force is observed as a breaking point before reaching the pre-determined depth of penetration. The destruction of the network is irreversible and thus, no breaking point is observed in the second cycle of the penetration test.

A breaking point is not observed (i) if stearic acid is used instead of hydroxystearic acid and/or (ii) if the composition has not been prepared according to the invention.

The value of the maximum force at the breaking point depends on the texture of the composition. In case of a very firm but penetrable composition, the maximum force is relatively high.

In the context of the present invention, "firmness" is the maximum force observed at the breaking point, expressed in [kg].

Thus, in the context of the present invention and for the sake of clarity, a

composition without a "breaking point" does not have a "firmness" expressed in [kg]. One embodiment of the invention relates to a composition comprising water, at least one lipophilic ingredient and hydroxystearic acid, wherein said composition has a firmness of at least 0.1 kg, preferably of at least 0.15 kg and most preferably of at least 0.16 kg. One embodiment of the invention relates to the use of hydroxystearic acid for preparing a composition with a breaking point, wherein the composition has preferably a firmness of at least 0.1 kg, and wherein said hydroxystearic acid is preferably 10-hydroxystearic acid, 12-hydroxystearic acid or a mixture thereof.

In a preferred embodiment of the invention, the composition comprises water, at least one lipophilic ingredient and hydroxystearic acid and has a firmness of at least 0.1 kg, wherein the difference between the shear stress of the composition at a shear rate of 400/s and the shear stress of the same composition at a shear rate of 600/s is less than 20 Pa. In this preferred embodiment, hydroxystearic acid is preferably 10-hydroxystearic acid, 12-hydroxystearic acid or a mixture thereof, and wherein hydroxystearic acid is most preferably 10-hydroxystearic acid.

As the compositions of the invention are spreadable despite of having a firm texture, an increased firmness is a desired feature: The higher the firmness of the

composition is, the less likely the composition will stain the inner side of the lid and/or of the peelable liner of a pot, even if transportation is rough. Surprisingly, the maximum force at the breaking point is higher if 10-hydroxystearic acid is used instead of 12-hydroxystearic acid. Thus, the present invention also relates to the use of 10-hydroxystearic acid for increasing the firmness of a yield- pseudoplastic fluid, wherein said composition is preferably a cosmetic composition.

One embodiment of the invention relates to a composition comprising water, at least one lipophilic ingredient and 10-hydroxystearic acid, wherein said composition has a firmness of at least 0.2 kg, preferably of at least 0.3 kg and most preferably of at least 0.4 kg. Such a firm but spreadable composition can be used to form a stick, e.g. cosmetic stick with a dome-shaped end. I n a preferred embodiment of the invention, the composition has a firmness of at least 0.2 kg and comprises:

• at least 70 weight% water,

• from 2 weight% to 10 weight% hydroxystearic acid,

• at least one lipophilic ingredient, and

• preferably at least one emulsifier,

wherein hydroxystearic acid is preferably 10-hydroxystearic acid, 12-hydroxystearic acid or a mixture thereof, and wherein hydroxystearic acid is most preferably 10- hydroxystearic acid.

When testing the penetration resistance of a composition according to the invention, the force necessary to maintain the pre-determined speed of the probe increases relatively quickly. I n a preferred embodiment of the invention, the force to maintain a penetration rate of 2 mm/s exceeds 0.1 kg before a penetration depth of 1 mm is reached. Again, the same conditions apply, i.e. a metallic cylinder having a diameter of 2 cm is inserted into the composition at room temperature.

Examples

The present invention is further illustrated by the following examples. Example 1: Two compositions (451 and 452) comprising 10-hydroxystearic acid are prepared:

451 452

Phase Ingredient (INCI) weight% weight%

A AQUA 79.6 79.6

A GLYCERIN 4 4

A XANTHAN GUM 0.2 0.2

A PHENOXYETHANOL; ETHYLHEXYLGLYCERIN 1 1

A CHLORPHENESIN 0.2 0.2

B CETEARYL GLUCOSIDE 1.5 1.5

B CETEARYL ALCOHOL 1 1

B CAPRYLIC/CAPRIC TRIGLYCERIDE 5 5

B 10-HYDROXYSTEARIC ACID 1 1

B OCTYLDODECANOL 2 2

B ISOHEXADECANE 4 4 B HYDROXYETHYL ACRYLATE/SODIUM 0.5 0.5

ACRYLOYLDIMETHYL TAURATE COPOLYMER

Whereas compositions 451 and 452 have the same ingredients in the same quantities, the manufacturing process is different. Due to the differences in the manufacturing process, ready-to-use compositions 451 and 452 have a different texture, resulting in different rheological properties. Composition 451 is prepared according to the invention, whereas composition 452 is a comparative example.

Manufacturing of composition 451:

mix all ingredients of phase A and heat up to 75-80°C

mix all ingredients of phase B and heat up to 75-80°C

- add phase B to phase A and homogenize with high shear (Ultra-Turrax^®,

13500 rpm)

cool down under stirring (low shear)

stop stirring at a temperature of 60°C and pour the hot composition into a cosmetic pot

- continue to cool down the composition to room temperature in the cosmetic pot. The composition in the pot has a firm texture after few hours at room temperature.

Preparation of composition 452:

mix all ingredients of phase A and heat up to 75-80°C

- mix all ingredients of phase B and heat up to 75-80°C

add phase B to phase A and homogenize with high shear (Ultra-Turrax^® 13500 rpm)

cool down under stirring (low shear) until the composition reaches room temperature. Once the composition has reached room temperature, the composition is still flowable.

pour the cooled down composition into a cosmetic pot

Rheological data for establishing a rheogram is collected. For collecting the rheological data (shear stress versus shear rate), an AR 550 Advanced Rheometer is used. A plate SST ST 40mm is used for the measurement. The force that is needed to achieve a certain turning speed allows the calculation of the shear stress and the shear rate of a composition. The following test parameters are used:

temperature: 25°C

shear rate ramp: 0-1000 1/s in 3 minutes

- measuring points: 60

quantity of composition used for the measurement: 0.8-lg

The rheograms of compositions 451 and 452 are shown in FIGU RE 2. The flow curve of composition 451 is the flow curve of a yield-pseudoplastic fluid according to the invention, the slope of the shear stress versus shear rate curve of the composition decreases to approximate zero at a shear rate of approximately 450/s. A plateau is reached. The shear stress at a shear rate of 600/s has approximatively the same value as the shear stress at a shear rate of 400/s.

The flow curve of comparative composition 452 resembles the flow curve of a Bingham plastic fluid, i.e. the plot of shear stress versus shear rate approximates a straight line with a constant slope as the shear rate is increased. No plateau has been reached when the measurement is stopped at a shear rate of 1000/s. The shear stress at a shear rate of 600/s is higher than the shear stress at a shear rate of 400/s.

Example 2:

Two further compositions (453 and 454) are prepared, similar to the compositions example 1. However, 12-hydroxystearic acid instead of 10-hydroxystearic acid is used:

453 454

Phase Ingredient (INCI) weight% weight%

A AQUA 79.6 79.6

A GLYCERIN 4 4

A XANTHAN GUM 0.2 0.2

A PHENOXYETHANOL; ETHYLHEXYLGLYCERIN 1 1

A CHLORPHENESIN 0.2 0.2

B CETEARYL GLUCOSIDE 1.5 1.5

B CETEARYL ALCOHOL 1 1

B CAPRYLIC/CAPRIC TRIGLYCERIDE 5 5 B 12-HYDROXYSTEARIC ACID 1 1

B OCTYLDODECANOL 2 2

B ISOHEXADECANE 4 4

B HYDROXYETHYL ACRYLATE/SODIUM 0.5 0.5 ACRYLOYLDIMETHYL TAURATE COPOLYMER

Whereas compositions 453 and 454 have the same ingredients in the same quantities, the manufacturing process is different (similar to example 1). Due to the differences in the manufacturing process, ready-to-use compositions 453 and 454 have a different texture, resulting in different rheological properties. Composition 453 is prepared according to the invention, whereas composition 454 is a comparative example.

Preparation of composition 453:

mix all ingredients of phase A and heat up to 75-80°C

- mix all ingredients of phase B and heat up to 75-80°C

add phase B to phase A and homogenize with high shear (Ultra-Turrax^®, 13500 rpm)

cool down under stirring (low-shear)

continue to cool down the composition to room temperature in the cosmetic pot. The composition in the pot has a firm texture after few hours at room temperature.

Preparation of composition 454:

- mix all ingredients of phase A and heat up to 75-80°C

mix all ingredients of phase B and heat up to 75-80°C

pour the cooled down composition into a cosmetic pot The rheograms of compositions 453 and 454 are shown in FIGU RE 3. For collecting the rheological data, the same equipment and test parameters as in example 1 are used.

The flow curve of composition 453 is the flow curve of a yield-pseudoplastic fluid according to the invention; the slope of the shear stress versus shear rate curve of the composition decreases to approximate zero at a shear rate of approximately 450/s. The difference between the shear stress of the composition 453 at a shear rate of 400/s and the shear stress of the same composition at a shear rate of 600/s is less than 5 Pa.

The flow curve of comparative composition 454 resembles the flow curve of a Bingham plastic fluid, i.e. the plot of shear stress versus shear rate approximates a straight line with a constant slope as the shear rate is increased. The shear stress at a shear rate of 600/s is higher than the shear stress at a shear rate of 400/s.

Whereas the flow curve of composition 451 (example 1; 10-hydroxystearic acid) and the flow curve composition 453 (example 2; 12-hydroxystearic acid) both show a plateau, there are quantitative differences. For composition 451, the plateau at shear rates from 400/s to 600/s corresponds to a shear stress of approximately 292 Pa. For the composition comprising 12-hydroxystearic acid instead of the preferred 10-hydroxystearic acid (composition 453), the plateau is less pronounced and the corresponding shear stress is lower. Examples 1 and 2 illustrate the importance of the manufacturing process: A composition prepared according the claimed manufacturing process has a particular texture, which is manifested in the respective rheological data. If the claimed manufacturing process is not followed (i.e. stirring is not stopped before reaching room temperature), the texture and the corresponding rheological data is different, even if the same ingredients in the same quantities are used.

Comparative example 3:

Two further compositions (455 and 456) are prepared, similar to the compositions of examples 1 and 2. However, stearic acid instead of a hydroxystearic acid is used: 455 456

Phase Ingredient (INCI) weight% weight%

A AQUA 79.6 79.6

A GLYCERIN 4 4

A XANTHAN GUM 0.2 0.2

A PHENOXYETHANOL; ETHYLHEXYLGLYCERIN 1 1

A CHLORPHENESIN 0.2 0.2

B CETEARYL GLUCOSIDE 1.5 1.5

B CETEARYL ALCOHOL 1 1

B CAPRYLIC/CAPRIC TRIGLYCERIDE 5 5

B STEARIC ACID 1 1

B OCTYLDODECANOL 2 2

B ISOHEXADECANE 4 4

B HYDROXYETHYL ACRYLATE/SODIUM 0.5 0.5 ACRYLOYLDIMETHYL TAURATE COPOLYMER

Whereas compositions 455 and 456 have the same ingredients in the same quantities, the manufacturing process is different (similar to examples 1 and 2). Despite of the difference in the manufacturing process, neither composition 455 nor composition 456 develop a firm texture.

Preparation of composition 455:

mix all ingredients of phase A and heat up to 75-80°C

mix all ingredients of phase B and heat up to 75-80°C

cool down under stirring (low shear)

continue to cool down the composition to room temperature in the cosmetic pot. The composition in the pot has not a firm texture after few hours at room temperature.

Preparation of composition 456:

mix all ingredients of phase A and heat up to 75-80°C

mix all ingredients of phase B and heat up to 75-80°C add phase B to phase A and homogenize with high shear (Ultra-Turrax^® 13500 rpm)

pour the cooled down composition into a cosmetic pot

The rheograms of compositions 455 and 456 are shown in FIGU RE 4. For collecting the rheological data, the same equipment and test parameters as in examples 1 and 2 are used.

The flow curves of comparative composition 455 and 456 resembles the flow curve of a Bingham plastic fluid, i.e. the plot of shear stress versus shear rate approximates a straight line with a constant slope, provided a shear rate of 700/s is not exceeded. No plateau is reached at shear rates between 400/s and 600/s. The shear stress at a shear rate of 600/s is higher than the shear stress at a shear rate of 400/s.

Qualitatively, the flow curve of composition 455 resembles the flow curve of composition 456, i.e. using the manufacturing process according to the invention does not result in a plateau when using stearic acid instead of hydroxystearic acid.

Example 4: A penetrometer TAXT plus Texture Analyzer of the company Stable Micro Systems is used for measuring the penetration resistance.

When collecting said data, a metallic cylinder having a diameter of 2 cm is inserted into the respective composition at constant velocity with a penetration rate of 2 mm/s. The test is stopped at a penetration depth of 5 mm whereas the pot holding the respective composition is filled to a height of 1 cm, i.e. the penetration test is stopped before the cylinder reaches the bottom of the pot. The pot has a diameter of 5 cm. The force necessary to maintain the penetration rate of 2 mm/s is continuously measured and indicated in [kg]. All tests are conducted at room temperature. In FIGURE 5, the penetration resistance data of composition 451 (10-hydroxystearic acid), composition 453 (12-hydroxystearic acid) and composition 455 (stearic acid) is shown. All of these compositions have been prepared according to the invention, i.e. stirring has been stopped before the respective mixture reaches room temperature. Composition 455, however, is a comparative example as stearic acid instead of hydroxystearic acid is used.

In case of comparative composition 455, the maximum force is observed when complete penetration depth is reached, i.e. at the deepest point of penetration. There is no breaking point. In contrast, when testing the penetration resistance of compositions 451 and 453, the maximum force is observed before complete penetration depth. Thus, both compositions have a breaking point.

However, the value for the maximum force, corresponding to the firmness of the composition, is different. For the composition comprising 10-hydroxystearic acid (451), firmness is approximately 0.2 kg, whereas the firmness for the composition 12-hydroxystearic acid is below 0.15 kg. According to the invention, 10- hydroxystearic acid is preferred because the corresponding compositions are particularly firm when the manufacturing process of the invention is used. Despite of the increased firmness, compositions comprising 10-hydroxystearic acid are easily spreadable on the skin.

In FIGURE 6, the penetration resistance data of composition 451 is compared to the data of composition 452. Whereas both compositions comprise 10-hydroxystearic acid, only composition 451 has been prepared according to the invention. In case of composition 451, the maximum force is reached before the deepest point of penetration. In case of comparative composition 452, the maximum force is reached at the deepest point of penetration despite that compositions 451 and 452 have the same ingredients. The same observation applies mutatis mutandis to compositions 453 and 454, both containing 12-hydroxystearic acid (see FIGU RE 7).

Examples 1, 2, 3 and 4 illustrate the importance of the manufacturing process: A composition which is easily spreadable despite of having a firm texture is achieved (i) if stirring is stopped before the respective mixture reaches room temperature and (ii) if hydroxystearic acid instead of stearic acid is used. Accordingly, a composition prepared according the claimed manufacturing process is the focus of the present invention. Such composition solves the problem underlying the present invention. A particularly firm but nonetheless easily spreadable composition is prepared when 10-hydroxystearic acid is used.

Example 5:

A cosmetic stick comprising water, at least one lipophilic ingredient and 10- hydroxystearic acid is prepared. Said stick is made of composition 470. In comparison to the compositions of example 1, a higher amount of 10-hydroxystearic acid is used in composition 470.

Preparation of the stick:

- mix all ingredients of phase A and heat up to 75-80°C

mix all ingredients of phase B and heat up to 75-80°C

cool down under stirring (low shear)

- stop stirring at a temperature of 60°C and filling the hot composition into a suitable canister, which optionally has a plastic dome cap at one end continue to cool down the composition to room temperature in the canister. The composition hardens, optionally forming a dome shape end inside the plastic dome cap.

The finished stick looks like an AP-DEO (antiperspirant-deodorant) stick. Although it is significantly softer than an AP-DEO stick, it is sufficiently solid and rigid to ensure its resistance at the time of its application. When applied to the skin, the part of the composition forming the top of the stick changes its texture/hardness and becomes easily spreadable onto the skin.

Claims

Composition comprising water, at least one lipophilic ingredient and hydroxystearic acid, wherein said composition is a yield-pseudoplastic fluid, and wherein said composition has a breaking point when penetration resistance is tested.

Composition according to claim 1, wherein the difference between the shear stress of the composition at a shear rate of 400/s and the shear stress of the same composition at a shear rate of 600/s is less than 20 Pa.

Composition according to claim 1 or 2, wherein the composition has a firmness of at least 0.1 kg and wherein the composition has preferably a firmness of more than 0.15 kg.

Composition according to any of claims 1 to 3, wherein the hydroxystearic acid is 10-hydroxystearic acid, 12-hydroxystearic acid or a mixture thereof.

Composition according to any of claims 1 to 4, wherein the hydroxystearic acid is 10-hydroxystearic acid.

Composition according to any of claims 1 to 5, wherein said composition comprises hydroxystearic acid in an amount of less than 3 weight%, preferably less than 2 weight% and most preferably less than 1.5 weight%, and wherein the minimal amount of hydroxystearic acid is preferably 0.1 weight%, more preferably 0.2 weight% and most preferably 0.5 weight%.

7. Composition according to any of claims 1 to 6, wherein said composition comprises more than 50 weight% water, preferably more than 60 weight% water and most preferably more than 70 weight% water.

8. Composition according to any of claims 1 to 7, wherein said composition comprises at least one emulsifier, and wherein said emulsifier is preferably a non-ionic emulsifier such as cetearyl glucoside, and wherein said emulsifier is preferably not an anionic emulsifier.

9. Composition according to any of claims 1 to 8, wherein the force to maintain a penetration rate of 2 mm/s exceeds 0.1 kg before a penetration depth of 1 mm is reached, when a metallic cylinder having a diameter of 2 cm is inserted into said composition at room temperature.

10. Pot comprising the composition according to any of claims 1 to 9, wherein said pot is or is not sealed with a peelable liner and wherein said pot has a preferably rotatable lid.

11. Stick made of a composition comprising water, at least one lipophilic

ingredient and hydroxystearic acid, wherein said stick is preferably a cosmetic stick with a preferably dome-shaped end.

12. Stick according to claim 11, wherein the stick is made of the composition according to any of claims 1 to 5 or 7 to 8, and/or wherein the stick comprises 10-hydroxystearic acid in an amount of at least 2 weight%, preferably in an amount of at least 3 weight%.

13. Method for preparing a composition comprising water, at least one lipophilic ingredient and hydroxystearic acid, the method comprising the steps:

fill the emulsion into containers before the emulsion has cooled down to room temperature,

wherein hydroxystearic acid is preferably 10-hydroxystearic acid, 12- hydroxystearic acid or a mixture thereof.

14. Method according to claim 13, wherein the containers are cosmetic pots or canisters with a dome-shaped end or a cone-shaped end.

15. Use of hydroxystearic acid for preparing a composition with a breaking point, wherein the composition has preferably a firmness of at least 0.1 kg and wherein said hydroxystearic acid is preferably 10-hydroxystearic acid.