WO2019063804A1

WO2019063804A1 - Cleansing and/or scrubbing dry granules

Info

Publication number: WO2019063804A1
Application number: PCT/EP2018/076496
Authority: WO
Inventors: Shoibal PATTANAIK; Gabriele DADALT SOUTO
Original assignee: L'oreal
Priority date: 2017-09-29
Filing date: 2018-09-28
Publication date: 2019-04-04

Abstract

The invention relates to an anhydrous granule comprising: a) at least one saturated fatty acid having 12 to 18 carbon atoms; b) at least one neutralizing agent; c) at least one polyol; and d) at least one filler. Said granule may be incorporated into a cleansing and/or exfoliating cosmetic composition.

Description

CLEANSING AND/OR SCRUBBING DRY GRANULES

The present invention relates to cleansing and/or exfoliating anhydrous granules that are useful for personal skin care.

The skin is the protective barrier for the human body. It protects the interior of the body from physical injury (such as trauma) and biological injury (such as bacteria, viruses or fungi). The skin of the human body comprises the dermis and the epidermis. The epidermis is the top most layer of the skin, and its superficial layer is called the stratum corneum.

The stratum corneum, or horny layer, is normally made up of 10 to 30 layers of dead cells. These cells are constantly being replaced by new cells from below. It is estimated that in adult skin it takes about a month for the stratum corneum to be completely replaced by new cells. The replacement time increases with aging, until around 120-150 days. The longer it takes to replace the dead cells, the more layers of dead cells accumulate.

It is therefore desirable to eliminate excess layers of dead skin cells from the skin surface in order to provide a shiny skin with a youthful appearance. The process of removing dead skin cells from the skin surface is called exfoliation. Currently, human skin is cleaned and/or exfoliated using a number of different ways, such as cleansing products with or without mechanical scrubbing using hard particles of any kind. These particles are also called scrub beads; they are used in solid form. It is known that the addition of scrub beads, such as perlite beads, provides a stronger and better cleansing ability to the skin, in particular pore cleansing. Scrubbing particles can be added to a number of cosmetic compositions, including creams, gels and, more recently, to powder.

Cosmetic compositions known as powder cleansers have been in the market, however such compositions are invariably composed of fine powder (i.e. less than 100 micrometers), such as surfactants and fillers and, during application of such products, there are high chances that the dusting caused by the composition may cause irritation and allergy through inhalation of powder particles. Moreover, these compositions tend to be highly hygroscopic and the scrub particles used in some commercial powder cleansers have a biodegradability concern. There is thus a need for stable cleansing and/or exfoliating compositions presenting a scrub-like effect, without the use of scrub beads such as perlite beads.

There is also a need for stable cleansing and/or exfoliating compositions providing reduced dusting and hygroscopicity.

Moreover, there is a need for exfoliating compositions with the properties mentioned above, and meanwhile which are biodegradable and easily spreadable on skin, with good dissolution and foaming properties.

The Applicant has now discovered that it is possible to formulate compositions in the form of anhydrous granules having the desired properties as described above, by combining specific fatty acids with a neutralizing agent, a polyol and a filler.

Accordingly, the present invention relates to an anhydrous granule comprising: a) at least one saturated fatty acid having 12 to 18 carbon atoms;

b) at least one neutralizing agent;

c) at least one polyol; and

d) at least one filler.

The anhydrous granule of the invention may be used as a facial or body cleanser and/or exfoliating composition. Moreover, the anhydrous granule of the invention is stable without softening over time and/or temperature change. By "stable", it is meant that the anhydrous granule does not undergo any significant change in its structure or properties for at least one month after its manufacture and especially for at least two months after its manufacture.

By "granule", it is meant a solid particle made by a granulation process. The granulation process typically uses a powder mixture as a starting material, in order to obtain granules. By "solid", it is meant a particle which does not flow under its own weight. By "anhydrous", it is meant that the granule comprises less than 5% of water by weight relative to the total weight of the dry granule, preferably less than 3% by weight, preferably less than 1 % by weight. Preferably, the anhydrous granule is totally devoid of water.

The anhydrous granule has preferably a particle size by volume Dv90 ranging from 250 micrometers to 850 micrometers. The anhydrous granule has preferably a particle size by volume Dv50 ranging from 400 micrometers to 600 micrometers. Preferably, said particle size range of the anhydrous granule of the invention confers an appearance of scrub-like texture, and this, without addition of scrub particles. The size range confers to the anhydrous granule the 2-in-1 property of cleansing and scrubbing.

The median particle size by volume Dv90 as disclosed in the present invention is a parameter for particle size distribution, referring to the maximum particle diameter below which 90% of the sample volume exists (see in A Basic Guide To Particle Characterization, page 10, published by Malvern Instruments Limited in 2012). Likewise, the median particle size by volume Dv50 as disclosed in the present invention is a parameter for particle size distribution, referring to the maximum particle diameter below which 50% of the sample volume exists.

The particle size by volume Dv90 and Dv50 of the anhydrous granule may be measured by static light scattering using a commercial granulometer such as the MasterSizer 3000 instrument from Malvern, with the aid of a Dry Powder Dispenser. The data are processed on the basis of the Mie scattering theory. This theory, which is exact for isotropic particles, makes it possible to determine, in the case of non-spherical particles, an "effective" particle diameter. This theory is especially described in the publication by Van de Hulst, H.C., "Light Scattering by Small Particles," Chapters 9 and 10, Wiley, New York, 1957. Preferably, the anhydrous granule according to the invention does not comprise any scrub bead, notably any perlite bead. Preferably, the anhydrous granule comprises less than 5% of scrub bead(s) by weight relative to the total weight of the dry granule, preferably less than 3% by weight, preferably less than 1 % by weight. Preferably, the anhydrous granule is totally devoid of any scrub bead.

According to another embodiment, the anhydrous granule according to the invention may comprise at least one scrub bead, preferably perlite beads.

The present invention also relates to a cosmetic composition for cleansing and/or exfoliating the skin comprising, in a physiologically acceptable medium, at least one anhydrous granule as defined above.

The present invention also relates to a process for preparing the anhydrous granule of the invention, comprising the following steps:

i) mixing at least one saturated fatty acid having 12 to 18 carbon atoms with at least one neutralizing agent and at least one polyol; ii) mixing the mixture of step i) with at least one filler and submitting the resulting mixture to a granulator, so as to obtain wet granules; and

iii) drying the wet granules of step ii), which are optionally sieved, in order to obtain anhydrous granules.

The present invention also relates to a method for cleansing and/or exfoliating the keratin materials, in particular the skin, comprising the application to the keratin materials, in particular the skin, of the anhydrous granule as described above, or of the above mentioned cosmetic composition.

The present invention also relates to the use of the anhydrous granule as defined above, for cleansing and/or exfoliating keratin materials, in particular the skin. It also relates to the use of the cosmetic composition as described above, for cleansing and/or exfoliating keratin materials, in particular the skin.

Such a cosmetic composition is a rinse off product. Thus, such a cosmetic composition is applied on skin (i.e. face and/or body), and then rinsed.

Other subjects and characteristics, aspects and advantages of the invention will emerge even more clearly on reading the description and the examples that follows.

In that which follows and unless otherwise indicated, the limits of a range of values are included within this range, in particular in the expressions "of between" and "ranging from ... to

Moreover, the expression "at least one" used in the present description is equivalent to the expression "one or more".

Throughout the instant application, the term "comprising" is to be interpreted as encompassing all specifically mentioned features as well optional, additional, unspecified ones. As used herein, the use of the term "comprising" also discloses the embodiment wherein no features other than the specifically mentioned features are present (i.e. "consisting of").

The anhydrous granule of the invention comprises:

a) at least one saturated fatty acid having 12 to 18 carbon atoms;

b) at least one neutralizing agent;

c) at least one polyol; and

d) at least one filler. The saturated fatty acid having 12 to 18 carbon atoms a) is preferably chosen from myristic acid, lauric acid, palmitic acid, stearic acid and mixtures thereof. Preferably the saturated fatty acid having 12 to 18 carbon atoms a) has 12 to 14 carbon atoms. Preferably, it is chosen from myristic acid, lauric acid and mixtures thereof.

Preferably, the anhydrous granule comprises a mixture of myristic acid and lauric acid. Preferably the weight ratio myristic acid : lauric acid is comprised between 1 and 1 .5.

The saturated fatty acid a) used in the present invention is preferably present in an amount ranging from 2% to 30% by weight of the total weight of the anhydrous granule, more preferably from 10 to 20% by weight.

The anhydrous granule of the invention further comprises at least one neutralizing agent b). Said neutralizing agent b) may be chosen from mineral bases such as potassium hydroxide, sodium hydroxide or ammonium hydroxide. It may be chosen from organic bases, in particular alkanolamines such as isopropanolamine, mono-, di- and triethanolamine, aminoethylpropanol and aminomethylpropanol.

The neutralizing agent b) is preferably chosen from mineral bases, preferably is potassium hydroxide or sodium hydroxide. The amount of base used depends on the amount of fatty acid(s) a) present in the anhydrous granule. A sufficient amount of base must be used to neutralize the fatty acid(s) a). Preferably, the fatty acid(s) a) is 90 to 100%, more preferentially 95 to 100%, neutralized. The neutralizing agent b) used in the present invention is preferably present in an amount ranging from 3% to 15% by weight of the total weight of the anhydrous granule, preferably from 5% to 10% by weight.

The anhydrous granule of the invention further comprises at least one polyol c). By "polyol", it is meant any organic molecule comprising at least two free hydroxyl groups. The polyol c) is preferably a polyol comprising from 2 to 8 carbon atoms. Preferably the polyol c) is chosen from glycerol, sorbitol, glycols such as butylene glycol, propylene glycol, isoprene glycol, dipropylene glycol, hexylene glycol and polypropylene glycol.

Preferably the polyol c) is sorbitol.

The polyol c) used in the present invention is preferably present in an amount ranging from 5% to 30% by weight of the total weight of the anhydrous granule, more preferably from 10 to 20% by weight. The anhydrous granule of the invention further comprises at least one filler d). The filler d) may be chosen from talc, starch such as corn starch, kaolin, mica, sericite, silica and notably hydrophobic colloidal silica, polyamide powders, poly-p-alanine powders, polyethylene powders and tetrafluoroethylene polymer powders. Preferably the filler may be chosen from talc, starch such as corn starch, kaolin, mica and sericite.

The filler d) used in the present invention is preferably present in an amount ranging from 40% to 80% by weight of the total weight of the anhydrous granule, more preferably from 45 to 70% by weight.

According to a preferred embodiment, the present invention relates to an anhydrous granule comprising, by weight of the total weight of said anhydrous granule:

a) from 10 to 20% by weight of at least one saturated fatty acid having 12 to 18 carbon atoms, preferably chosen from myristic acid, lauric acid and mixtures thereof;

b) from 5 to 10% by weight of at least one neutralizing agent, preferably chosen from mineral bases;

c) from 10 to 20% by weight of at least one polyol, preferably comprising from 2 to 8 carbon atoms; and

d) from 45% to 70% by weight of at least one filler, preferably chosen from talc, starch such as corn starch, kaolin, mica and sericite.

The anhydrous granule of the present invention may comprise at least one additive. A person skilled in the art can adjust the type and amount of additives present in the anhydrous granules according to the invention by means of routine operations, so that the desired cosmetic properties and stability properties for these anhydrous granules are not affected by the additives. Said additive may be chosen from emollients, colorants, fragrances and active agents.

The emollients may be chosen from polyoxylenated polyethylene glycol and/or shea butter.

The colorants may be chosen from pigments, dyes and nacres. Pigments include white or colored particles, mineral or organic, intended for coloring and/or opacifying the resultant product. Preferably, pigments or nacres, if present, are present in an amount ranging from 0.01 to 30% by weight, more preferably from 0.01 to 20% by weight relative to the total weight of the anhydrous granule.

The fragrance may preferably be menthol. The active agents may be chosen form vitamins, antioxidants and vegetal extracts, such as Camellia sinensis leaf extract or charcoal powder.

The present invention also relates to a cosmetic composition, notably for cleansing and/or exfoliating keratin materials, in particular the skin, comprising, in a physiologically acceptable medium, at least one anhydrous granule of the invention as described above.

The anhydrous granule according to the invention may be applied by any means enabling a uniform distribution, in particular using a finger, or a cotton ball, a rod, a brush, gauze, or a spatula, and can be removed by rinsing with water.

The anhydrous granule of the invention may be implemented so as to improve the general state of the epidermis, in particular the skin.

i) mixing at least one saturated fatty acid having 12 to 18 carbon atoms with at least one neutralizing agent and at least one polyol;

ii) mixing the mixture of step i) with at least one filler and submitting the resulting mixture to a granulator, so as to obtain wet granules; and

Such a process of the invention is easy to perform, and without issues such as dust generated during production. Step i) of the above process comprises mixing at least one saturated fatty acid having 12 to 18 carbon atoms with at least one neutralizing agent and at least one polyol. It may be performed under heating, preferably at a temperature comprised between 60°C and 80°C.

The resulting mixture obtained in step i) is mixed with at least one filler, and then submitted to a granulator, so as to obtain wet granules. Preferably said step is performed at room temperature. Preferably the granulator is a Rapid Mixing Granulator, a Sigma Mixer, or a Universal Mixer.

The wet granules obtained in step ii) are finally dried, so as to obtain anhydrous granules of the invention. Before or after drying, the wet granules are preferably sieved, preferably through a mesh having the required size for obtaining a Dv90 particle size of 250 to 850 μηι. Drying can be performed in an industrial Tray Drying Oven with hot air circulation or in a Fluid Bed Drier. Drying temperature should be between 30°C and 60°C, preferentially between 40°C and 50°C.

The present invention also relates to a method for cleansing and/or exfoliating keratin materials, in particular the skin, comprising the application to the keratin materials, in particular the skin, of the anhydrous granule of the invention, or of a cosmetic composition comprising said anhydrous granule.

The invention also relates to the use of the anhydrous granule of the invention, or of a cosmetic composition comprising said granule, for cleansing and/or exfoliating keratin materials, in particular the skin.

The following examples serve to illustrate the invention without, however, being limiting in nature. EXAMPLES

Example 1 : Preparation of a composition according to the present invention

Composition I has the following composition:

Composition I was included in the following composition (composition la) according to the process detailed below, in order to obtain anhydrous granules according to the present invention:

Composition la

Concentration

Phase Raw material

(% w/w)

A Composition I 41 ,85

A TALC 7,3

POLYETHYLENE

A 0,05

GLYCOL (14.000 OE)

CAMELLIA SINENSIS

A 0,01

LEAF EXTRACT (and) DEXTRIN

A BLUE 1 LAKE 0,0436

A IRON OXIDES 0,45635

ZEA MAYS (CORN)

STARCH

A Qs 100

(amidon de mal^'s B, from

Roquette)

B TALC 2,7

B FRAGRANCE 0,3

In a vessel, the lauric acid, myristic acid and sorbitol solution are weighted and heated up to 70°C. Potassium hydroxide is added for neutralization of fatty acids, and a "play dough" soap component is formed: this corresponds to composition I.

At room temperature, 41 .85% of composition I is mixed with ingredients of phase A, and then granulated in a Stephan UMC 5 with double jacket and granulating insert at 300 rpm and room temperature. The resulting wet granules are sieved through a mesh size -18-20 (for obtaining dry granules of Dv90 of between 250μηι and850μm) and dried at 50°C until Loss on Drying (LOD) < 5%. Phase B is mixed with the dry granules as the final step. Finally, anhydrous granules according to the present invention are obtained.

Composition I was also included in the following composition (composition lb) according to the process detailed above, in order to obtain anhydrous granules according to the present invention:

Composition lb

Concentration

Phase Raw material

(% w/w)

A Composition I 41 ,85

A TALC 6,4

POLYETHYLENE

A 0,05

GLYCOL (14.000 OE)

CAMELLIA SINENSIS

A LEAF EXTRACT (and) 0,01

DEXTRIN

A BLUE 1 LAKE 0,0436

A IRON OXIDES 0,45635

A SILICA 0,288

ZEA MAYS (CORN)

STARCH

A Qs 100

(amidon de ma^'is B, from

Roquette)

B FRAGRANCE 0,4

B TALC 3,6

B SILICA 0,012 • The anhydrous granules of the present invention (granulated cleanser of composition la) were evaluated by the Sensory Expert Foam Panel (15 to 16 women) in China and compared with Biore Baking Soda, a commercial product notably comprising sodium bicarbonate, citric acid, sodium cocoyl isethionate, starch and silica.

The method used for the comparison was objective evaluation of sensory characteristics by said trained expert panel using standard criteria and gesture, in which the panelists give scores to each attribute.

The results show that the granulated cleanser of the invention has more coverage on application and stronger rinse-off ability, and also less dry and tight skin finish. The granulated cleanser also has stronger foam density, homogeneity and volume, and smaller size of bubbles.

• The granulated cleanser of composition la was also compared with Gamier Matcha Foam. Gamier Matcha Foam has the following composition:

The granulated cleanser of the invention (i.e. composition la) was significantly higher on spreadability, dissolution, speed & quantity of foaming and bigger size bubbles, and significantly lower on sticky. In addition, the average amount of water and number of splashes required for rinse off of granulated powder cleanser was lower than of Matcha Foam. This test was performed by a QDA panel, in which the scores for each attribute are given as a relative profile between both formulas. · A study with 15 volunteers was also performed to comparing the average quantity per use of the granulated cleanser of the present invention with the above-mentioned soap-based gel formula (Garnier Matcha Foam). For this study, the volunteers used the products at home for 7 days and were asked back to use the product in front of the evaluator, who weighed the packs before and after the volunteer's use. The average weight difference was used to compare the quantity per use of each product.

The results show that the average quantity per use of the granulated cleanser of the invention is lower than the soap-base benchmark (0.31 g against 0.86g per use).

Thus, the granulated cleanser of the invention is efficient for cleansing at smaller average quantity per use.

Example 2: Preparation of a composition according to the present invention

Composition II has the following composition:

Composition III has the following composition:

Compositions II and III were included in the following composition according to the process detailed in Example 1 , in order to obtain anhydrous granules according to the present invention: Concentration

Phase Raw material

(% w/w)

A Composition II 42

A TALC 6,325

CHARCOAL POWDER

(and) POLYGLYCERYL- 10 STEARATE (and)

POLYGLYCERYL-10

MYRISTATE (and)

A 0,1 POLYGLYCERIN-10

(25% by weight of active

material)

(WD-VCB25 of Daito

Kasei Kogyo)

A IRON OXIDES 0,5

ZEA MAYS (CORN)

STARCH

A Qs 100 (amidon de mal^'s B,

Roquette)

B Composition III 5

Claims

1. An anhydrous granule comprising:

a) at least one saturated fatty acid having 12 to 18 carbon atoms;

b) at least one neutralizing agent;

c) at least one polyol; and

d) at least one filler.

2. The anhydrous granule of claim 1 , wherein the saturated fatty acid a) is chosen from myristic acid, lauric acid, palmitic acid, stearic acid and mixtures thereof.

3. The anhydrous granule of claim 1 or 2, wherein the saturated fatty acid a) is present in an amount ranging from 2% to 30% by weight of the total weight of the anhydrous granule.

4. The anhydrous granule of any one of claims 1 to 3, wherein the neutralizing agent b) is chosen from mineral bases, preferably from potassium and sodium hydroxides.

5. The anhydrous granule of any one of the claims 1 to 4, wherein the polyol c) is a polyol comprising from 2 to 8 carbon atoms, and preferably chosen from glycerol, sorbitol, and glycols such as butylene glycol, propylene glycol, isoprene glycol, dipropylene glycol, hexylene glycol and polypropylene glycol.

6. The anhydrous granule of any one of the claims 1 to 5, wherein the polyol c) is present in an amount ranging from 5% to 30% by weight of the total weight of the anhydrous granule.

7. The anhydrous granule of any one of the claims 1 to 6, wherein the filler d) is chosen from talc, starch such as corn starch, kaolin, mica, sericite, silica and notably hydrophobic colloidal silica, polyamide powders, poly-p-alanine powders, polyethylene powders and tetrafluoroethylene polymer powders.

8. The anhydrous granule of any one of the claims 1 to 7, wherein the filler d) is present in an amount ranging from 40% to 80% by weight of the total weight of the anhydrous granule.

9. The anhydrous granule of any one of claims 1 to 8, wherein it has a particle size by volume Dv90 ranging from 250 micrometers to 850 micrometers.

10. A process for preparing the anhydrous granule according to any one of claims 1 to 9, comprising the following steps:

11. A cosmetic composition comprising, in a physiologically acceptable medium, at least one anhydrous granule according to any one of claims 1 to 9.

12. A method for cleansing and/or exfoliating the keratin materials, in particular the skin, comprising the application to the keratin materials, in particular the skin, of the anhydrous granule of any one of claims 1 to 9, or of the cosmetic composition of claim 1 1 .

13. Use of the anhydrous granule of any one of claims 1 to 9 for cleansing and/or exfoliating keratin materials, in particular the skin.

14. Use of the cosmetic composition of claim 1 1 for cleansing and/or exfoliating keratin materials, in particular the skin.