USE OF A PARTICULAR METAL OXIDE FOR THE PHOTOCONVERSOIN OF ORGANIC COMPOUNDS ON KERATIN MATERIALS

Abstract

The present invention relates to the use, for reducing and/or eliminating the deposits of organic compounds at the surface of keratin materials or at the surface of objects in contact with said keratin materials, of solid particles comprising at least one metal oxide OM1 of formula A.sub.aB.sub.bO.sub.n-x, in which: A denotes a metal chosen from bismuth, calcium, sodium, lanthanum, barium, copper, tin, magnesium, zinc and silver; B denotes a metal chosen from tungsten, vanadium, gallium, niobium and strontium; a is an integer within the range of from 1 to 4; b is an integer within the range of from 1 to 10; n is an integer within the range of from 3 to 6; and x is a decimal number of less than n, within the range of from 0.1 to 5. The present invention also relates to a method for the cosmetic treatment of keratin materials or of the surface of an object in contact with the keratin materials, using a cosmetic composition or an article comprising such solid particles, followed by exposure to light.

Claims

1. Use, for preventing, reducing and/or eliminating the deposits of organic compounds at the surface of keratin materials, in particular human keratin materials, or at the surface of objects in contact with said keratin materials, of solid particles comprising at least one metal oxide OM1 of formula A.sub.aB.sub.bO.sub.n-x, in which: A denotes a metal chosen from bismuth, calcium, sodium, lanthanum, barium, copper, tin, magnesium, zinc and silver; B denotes a metal chosen from tungsten, vanadium, gallium, niobium and strontium; a is an integer within the range of from 1 to 4; b is an integer within the range of from 1 to 10; n is an integer within the range of from 3 to 6; and x is a decimal number of less than n, within the range of from 0.1 to 5.

2. Use according to claim 1, in which A is chosen from bismuth and barium, and preferably A denotes bismuth.

3. Use according to claim 1, in which B is chosen from tungsten and vanadium, and preferably B denotes tungsten.

4. Use according to claim 1, in which the oxide OM1 has the formula Bi.sub.2WO.sub.6-x, with x a decimal number within the range of from 0.2 to 1.5, preferably from 0.3 to 1; and better still x is greater than or equal to 0.5 and strictly less than 1.

5. Use according to claim 1, in which the metal oxide OM1 is combined with a second metal oxide OM2 of formula M.sub.cO.sub.k, in which: M denotes a transition metal; c is an integer within the range of from 1 to 3; and k is a decimal number within the range of from 0.1 to 4.

6. Use according to claim 1, in which the oxide OM2 has the formula CuO.

7. Use according to claim 5, in which the molar ratio of the amount of metal oxide OM1 to the amount of metal oxide OM2 is greater than or equal to 1, preferably greater than or equal to 2, more preferentially greater than or equal to 3, even more preferentially greater than or equal to 4, and better still greater than 4.

8. Use according claim 1, in which the solid particles comprising said at least one metal oxide OM1 are obtained, or capable of being obtained, by flame spray pyrolysis.

9. Use according to claim 1, in which the solid particles comprising said at least one metal oxide OM1 have a number-average diameter ranging from 1 to 1000 nm, preferably from 10 to 200 nm.

10. Use according to claim 1, for preventing, reducing and/or eliminating the deposits of proteins and fatty substances secreted by the body, and in particular sebum deposits.

11. Method for the cosmetic treatment of keratin materials or of the surface of an object in contact with the keratin materials, comprising: (1) applying to said materials or to said surface a cosmetic composition comprising solid particles comprising at least one metal oxide OM1 of formula A.sub.aB.sub.bO.sub.n-x as defined claim 1; then (2) exposing said materials or said surface to natural or artificial light.

12. Method according to claim 11, characterized in that the cosmetic composition used in step (1) further comprises at least one metal oxide OM2 of formula M.sub.cO.sub.k, present in said particles comprising at least one metal oxide OM1 or in different solid particles, wherein for M.sub.cO.sub.k: M denotes a transition metal; c is an integer within the range of from 1 to 3; and k is a decimal number within the range of from 0.1 to 4.

13. Method according claim 11, characterized in that the content of metal oxide OM1 in the cosmetic composition ranges from 0.4% to 40% by weight, preferably from 0.5% to 20% by weight, better still from 1% to 10% by weight, and even more preferentially from 1.5% to 5% by weight, relative to the total weight of the composition.

14. Method according to claim 11, characterized in that the content of metal oxide OM2 ranges from 0.1% to 10% by weight, preferably from 0.15% to 5% by weight and better still from 0.25% to 1.5% by weight, relative to the total weight of the composition.

15. Method for the cosmetic treatment of keratin materials, comprising: (1) bringing said materials into contact with an article comprising solid particles comprising at least one metal oxide OM1 of formula A.sub.aB.sub.bO.sub.n-x as defined in claim 1; then (2) exposing said article to natural or artificial light.

16. Method according to claim 15, characterized in that the article used in step (1) further comprises at least one metal oxide OM2 of formula M.sub.cO.sub.k, present in said particles comprising at least one metal oxide OM1 or in different solid particles, wherein for M.sub.cO.sub.k: M denotes a transition metal; c is an integer within the range of from 1 to 3; and k is a decimal number within the range of from 0.1 to 4.

17. Method according to claim 12, wherein the molar ratio of the amount of metal oxide OM1 to the amount of metal oxide OM2 is greater than or equal to 1, preferably greater than or equal to 2, more preferentially greater than or equal to 3, even more preferentially greater than or equal to 4, and better still greater than 4.

18. Method according to claim 11, characterized in that step (2) is carried out by photoirradiation, using a light source that emits one or more electromagnetic waves with a wavelength of between 200 nm in the ultraviolet range and 3000 nm in the infrared range.

19. Method according to claim 18, characterized in that the light source is an LED lamp emitting radiation with a wavelength in the visible range.

Description

EXAMPLES

[0169] In the examples which follow, the particles are prepared in a flame spray pyrolysis device (or FSP device) in which the liquids are provided to the burner via a capillary nozzle (500 m diameter capillary). The flame produced is enclosed in a tube surrounding the pyrolysis flame. The tube is positioned above the nozzle of the FSP device. The tube is a cylinder made of metal or quartz having a length of between 20 and 60 cm, in particular between 30 and 50 cm, for instance 40 cm. The flame generally has a length of between from 5 to 15 cm and is at a temperature of between 500 C. and 2000 C. The precursors of metals (such as Bi, W, Cu) which are sprayed are burnt in the flames, leading to the formation of particles. The particles are then collected upstream on a glass fibre filter which is maintained preferably at a temperature of between 350 C. and 420 C. The distance between the FSP nozzle and the filter for collecting the particles is between 40 and 80 cm, preferably between 55 and 65 cm.

Example 1: Preparation of Particle Powders by FSP

[0170] A composition C1 is prepared by dissolving 250 mM of ammonium metatungstate hydrate and 500 mM of bismuth nitrate in an organic solvent constituted of a diethylene glycol monobutyl ether/absolute ethanol/acetic acid mixture.

[0171] Next, this composition C1 and also pure oxygen are injected into the FSP device.

[0172] 1.1. Preparation of Bi.sub.2WO.sub.6-x Particles (Invention)

[0173] The flow rates used for the injection are 7 ml/min of composition C1 and 4 l/min of gas (O.sub.2).

[0174] A powder is thus obtained, which is subjected to a thermal post-treatment by exposing it to a temperature of 300 C. for 1 hour, which makes it possible to improve its crystallinity.

[0175] The powder has a yellow-green colour and contains Bi.sub.2WO.sub.6-x particles with x being a decimal number greater than 0.1 and strictly less than 1.

[0176] The number-average size of the particles is 25 nm (measured by X-ray diffraction or XRD).

[0177] 1.2. Preparation of Bi.sub.2WO.sub.6 Particles (Comparative)

[0178] The flow rates used for the injection are 7 ml/min of composition C1 and 5 l/min of gas (O.sub.2).

[0179] A powder is thus obtained, which is subjected to a thermal post-treatment by exposing it to a temperature of 300 C. for 1 hour.

[0180] The powder has a yellow-green colour and contains Bi.sub.2WO.sub.6 particles.

[0181] The number-average size of the particles is 25 nm (measured by X-ray diffraction or XRD).

[0182] 1.3. Characterization of the Particles

[0183] The Bi.sub.2WO.sub.6-x and Bi.sub.2WO.sub.6 particles prepared in 1.1 and 1.2 above are differentiated by Raman spectroscopy in the visible zone between 400 and 500 nm in particular by a higher absorbance (typically around 20% higher) for the Bi.sub.2WO.sub.6 particles compared to those of Bi.sub.2WO.sub.6-x.

[0184] The two types of particles are also differentiated by electron paramagnetic resonance spectroscopy (or EPR spectroscopy). The EPR spectrum of the Bi.sub.2WO.sub.6-x particles prepared in 1.1 above typically has a signal at g=2.002, which is characteristic of an oxygen atom vacancy in the crystal lattice of Bi.sub.2WO.sub.6. The method is very sensitive and ensures that there is indeed a suboxide present with x greater than 0.1.

[0185] On the contrary, the Bi.sub.2WO.sub.6-x and Bi.sub.2WO.sub.6 particles are not generally differentiated by the positioning of the peaks in XRD.

[0186] Generally, the metal oxide particles according to the invention are suboxides (for example of formula Bi.sub.2WO.sub.6-x): [0187] 1) having, in X-ray diffraction (XRD), a positioning of the peaks that is similar to that of its stoichiometrically oxidized homologues (for example Bi.sub.2WO.sub.6); [0188] 2) having a Raman spectroscopy profile such that their absorbance in the zone 400-500 nm is at least 5% and preferably at least 10% lower than that of its stoichiometrically oxidized homologues (for example Bi.sub.2WO.sub.6); and/or [0189] 3) having an EPR spectroscopy profile comprising a signal in the region of 2, in particular g=2.002, that its stoichiometrically oxidized homologues (in particular Bi.sub.2WO.sub.6) do not have.

Example 2: Preparation of Particle Mixtures by FSP

[0190] A composition C2 is prepared by dissolving together 25 mM of copper nitrate, 250 mM of ammonium metatungstate hydrate and 500 mM of bismuth nitrate in an organic solvent constituted of a diethylene glycol monobutyl ether/absolute ethanol/acetic acid mixture.

[0191] Next, this composition C2 and also pure oxygen are injected into the FSP device.

[0192] 2.1. Preparation of a Mixture of Bi.sub.2WO.sub.6-x Particles and CuO Particles (Invention)

[0193] The flow rates used for the injection are 7 ml/min of composition C2 and 4 l/min of gas (O.sub.2).

[0194] A powder is thus obtained, which is subjected to a thermal post-treatment by exposing it to a temperature of 300 C. for 1 hour. The powder has a light brown colour and is formed of a mixture of Bi.sub.2WO.sub.6-x particles (with x being a decimal number greater than 0.1 and strictly less than 1) and CuO particles.

[0195] The EPR spectrum of the powder obtained has a signal at g=2.002, which is characteristic of an oxygen atom vacancy compared to the crystal lattice of Bi.sub.2WO.sub.6.

[0196] The number-average size of the particles is 20 nm (measured by XRD) for the Bi.sub.2WO.sub.6-x particles and 2.5 nm (measured by XRD) for the CuO particles.

[0197] The molar ratio of the amount of Bi.sub.2WO.sub.6-x relative to the amount of CuO in the powder is 20.

[0198] 2.2. Preparation of a Mixture of Bi.sub.2WO.sub.6 Particles and CuO Particles (Comparative)

[0199] The flow rates used for the injection are 7 ml/min of composition C2 and 7 l/min of gas (O.sub.2).

[0200] A powder is thus obtained, which is subjected to a thermal post-treatment by exposing it to a temperature of 300 C. for 1 hour.

[0201] The powder has a light brown colour and is formed of a mixture of Bi.sub.2WO.sub.6 particles and CuO particles.

[0202] The number-average size of the particles is 20 nm (measured by XRD) for the Bi.sub.2WO.sub.6 particles and 2.5 nm (measured by XRD) for the CuO particles.

[0203] The molar ratio of the amount of Bi.sub.2WO.sub.6 relative to the amount of CuO in the powder is 20.

Example 3: Tests for Elimination of Sebum in a Thin Layer Under Natural Light Irradiation

[0204] 5 identical plates are prepared, by each time spreading a layer of artificial sebum (33 mg) composed of oleic acid on a glass plate having a surface area of around 10 cm.sup.2.

[0205] Next, deposited on the surface of each plate, are 10 mg of one of the following powders: [0206] On plate 1 and plate 5: the powder formed of the Bi.sub.2WO.sub.6-x particles from example 1.1 (invention) is deposited; [0207] On plate 2: the powder formed of the Bi.sub.2WO.sub.6 particles from example 1.2 (comparative) is deposited; [0208] On plate 3: the powder formed of the mixture of Bi.sub.2WO.sub.6-x and CuO particles from example 2.1 (invention) is deposited; [0209] On plate 4: the powder formed of the mixture of Bi.sub.2WO.sub.6 and CuO particles from example 2.2 (comparative) is deposited.

[0210] Next, plates 1 to 4 are exposed to moderate daylight (38 mW/cm.sup.2) for a total duration of 60 minutes. Then, the plates are weighed to deduce the amount of sebum which has disappeared therefrom after 30 minutes, then after 60 minutes of light exposure.

[0211] The results obtained, in terms of percentage by weight of sebum that has disappeared, are given in detail in Table 1 below.

TABLE-US-00001 TABLE 1 Degree of disappearance of Degree of disappearance of Plate the sebum at t = 30 min the sebum at t = 60 min 1 - invention 50% 61% 2 - comparative 30% 42% 3 - invention 82% 93% 4 - comparative 31% 39%

[0212] In order to carry out a control, plate 5 (identical to plate 1) was not exposed to light. No disappearance of the sebum at t=60 min was observed (degree of disappearance measured less than 5% by weight).

[0213] The results above show that the use of the particles according to the present invention makes it possible to eliminate the sebum significantly more effectively than the use of the comparative particles. The powder formed from the Bi.sub.2WO.sub.6-x particles gives excellent results, and the powder formed from the mixture of Bi.sub.2WO.sub.6-x and CuO particles makes it possible to further increase the effectiveness.

Example 4: Tests for Elimination of Sebum on Heads of Hair

[0214] A head of hair comprising 1000 mg of sebum is considered. Half is on the area of the head of hair that is visible, namely a surface area of 1000 cm.sup.2. Thus, on the visible surface area, there is 0.5 mg of sebum per cm.sup.2. This amount is sufficient to give the hair a partially dirty appearance. In particular, when a comb is passed through the head of hair, the hairs have a tendency to remain clumped together revealing furrows at the location where the teeth of the comb have passed through.

[0215] Test 1:

[0216] In a first test, a composition is produced by dispersing 1000 mg of the powder formed from the Bi.sub.2WO.sub.6-x particles from example 1.1 in 50 ml of ethanol. 12 grams of this composition are applied to the head of hair, then there is a waiting time of 10 minutes for the hair to dry.

[0217] The hair is then subjected to natural lighting (sunlight) in an inside environment (behind a window) estimated at 20 mW/cm.sup.2. It is observed that 1 hour is needed to sufficiently eliminate the sebum that is on the surface and to reach a level where it becomes invisible.

[0218] In particular, it is observed that the hair treated is shiny with significantly better strand separation after combing than before treatment with combing. The treated hair appears clean as if it had just been washed, grease no longer appears on the hair, unlike the hair before treatment, which appears very greasy due to the presence of sebum.

[0219] Test 2:

[0220] Test 1 is repeated, using a composition obtained by dispersing 1000 mg of the powder formed from the mixture of Bi.sub.2WO.sub.6-x and CuO particles from example 2.1 in 50 ml of ethanol.

[0221] It is observed that 28 minutes are needed to sufficiently eliminate the sebum that is on the surface and to reach a level where it becomes invisible.

[0222] Test 3:

[0223] Test 1 is repeated, using 12 grams of ethanol (with no particles).

[0224] No change in the appearance of the head of hair is observed, the hair still appears greasy.

[0225] Test 4:

[0226] Test 1 is repeated, using a composition obtained by dispersing 1000 mg of the powder formed from the mixture of Bi.sub.2WO.sub.6 and CuO particles from example 2.2 in 50 ml of ethanol.

[0227] After one hour, the hair is less greasy but does not appear clean. This is due to the fact that the elimination efficiency is insufficient, leaving around 35% to 40% of sebum on the visible surface of the head of hair.

[0228] Test 5:

[0229] Test 2 is repeated, but leaving the hair in the dark after the 10 minutes of drying.

[0230] No change in the appearance of the head of hair is observed, the hair still appears greasy.

Example 5: Test for Maintaining the Cleanliness of a Head of Hair

[0231] A cosmetic composition is produced by dispersing 400 mg of the powder formed from the Bi.sub.2WO.sub.6-x particles from example 1.1 in 50 ml of ethanol.

[0232] The test is carried out on a model having a head of mid-length hair which has just been washed in the evening at 22:00. The head of hair is sufficiently stripped of sebum for the hair to appear clean. Once the hair is dry, 12 grams of the cosmetic composition above is applied, targeting the roots and carrying out a massage at the roots with the fingertips. Overnight the model's scalp produces approximately 500 mg of sebum, which is distributed as the hours go by following various contacts (pillow). Then it produces another 500 mg of sebum during the day, here considered as ranging from 10:00 to 22:00. During this second period, the sebum is distributed also along the length of the hair following various contacts (hand, comb, etc.).

[0233] The illumination of the model's head of hair is started in the morning at a relatively low level of 10 mW/cm.sup.2. From 08:00 to 09:00, owing to the application carried out the evening before of the composition comprising particles according to the invention, the 500 mg of sebum produced during the night are destroyed in 1 hour.

[0234] The rest of the day, the particles according to the invention continue to destroy the sebum that appears on the scalp then migrates to the roots before being taken away by contacts and other movements. At the end of the day, it is observed that the hair has remained generally clean. Thus, the model does not feel the need to wash their hair in the evening.

[0235] The next day, the hair is slightly dirty on waking, but regains a clean appearance during the morning in the presence of light.

Example 6: Tests Using a Brush

[0236] A brush is produced by adhesive bonding, to a metal base, a series of 80 bristles made of absorbent foam that are 3 mm wide and 1 cm long. Then 12 ml of the composition from Example 4Test 2 (dispersion of 1000 mg of powder formed from the mixture of the Bi.sub.2WO.sub.6-x and CuO particles in 50 ml of ethanol) are sprayed onto the brush, which is then left to dry.

[0237] This brush, when it is passed through the hair and the roots, absorbs a portion of the sebum while retaining the particles at the surface of the foam. This property stems from the fact that the contact is dry (no solvent). Next, the brush is placed (bristles downwards) 5 cm above a light source (series of four 1 W LED lamps), until the sebum is eliminated.

[0238] One variant consists in using a base made of plexiglass and a series of diodes placed under the base. Thus, it is possible to brush the hair, collect the sebum and begin to eliminate the sebum from the moment of contact. Afterwards, when the user puts the brush down, the illumination continues in order to finish eliminating the sebum collected by the foam bristles.

Example 7: Tests on Packaging

[0239] For these tests, use is made of two identical copies of packaging made of brown cardstock intended to cover a box containing a cosmetic product such as a perfume.

[0240] In a first test, a tester places their fingers on this packaging, a visible mark remains on the packaging, owing to the fact that the tester's fingers are covered with a thin layer of sebum.

[0241] In the second test, the packaging is pretreated by spraying onto the cardstock an ethanolic dispersion of particles according to the invention. For this, 10 mg of the powder formed of the mixture of Bi.sub.2WO.sub.6-x and CuO particles (example 2.1) are dispersed in 10 ml of absolute ethanol, then this dispersion is sprayed onto the cardstock which is then left to dry. It is observed that when a tester places their fingers on this packaging, a visible mark remains on the packaging, owing to the fact that the fingers are covered with a thin layer of sebum.

[0242] Then the two packagings are arranged under light obtained from a 1 W yellow spotlight at 20 cm, representative of shop lighting.

[0243] After 10 minutes, it is observed that the finger marks on the packaging of the second test gradually disappear until they become invisible after 1 hour. This disappearance is not observed on the packaging from the first test.