GRAPHIC CARBON NITRID CONTAINING AN OXYGEN ATOM AS A PRODUCT FOR SUNSCREEN, PAINT OR FILLER

Abstract

GRAPHITICAL CARBON NITRIDE CONTAINING ONE OXYGEN ATOM AS A SUNSCREEN, PAINT, OR FILLER. The present invention relates primarily to the use of graphitic carbon nitride containing at least one oxygen atom as a paint active, pigment, plastic filler, cosmetic active, and / or sunscreen, such as a UVA and / or UVB absorber. Graphitic carbon nitride can exhibit UVA and / or UVB absorption properties and white to yellow color absorption, and is therefore useful as a UV absorber for various products requiring coloring properties and an attractive appearance. Figure for abstract: none

Description

Title of the invention: GRAPHIC CARBON NITRID CONTAINING AN OXYGEN ATOM AS PRODUCT FOR SUNSCREEN, PAINT OR CHARGING technical field

[0001] The present invention relates mainly to a graphitic carbon nitride containing at least one oxygen atom (in particular functionalized with hydroxyl groups, preferably a graphitic carbon nitride functionalized with an N-oxide, or nitroso groups and hydroxyl groups) intended to be used as an ultraviolet (UVA and / or UVB) absorbing material in cosmetic or paint products or as fillers, in particular in plastics. CONTEXT OF THE INVENTION

[0002] The UV protection effect is one of the essential factors in cosmetic products. Graphitic carbon nitride, which is an inorganic compound, is known to exhibit UV absorption properties. Some documents relating to graphitic carbon nitride have already been published.

[0003] For example, document CN104801326A discloses photocatalytic materials based on surface-hydroxylated nanoporous carbon nitride. However, this document makes no mention of the use of carbon nitrides as ultraviolet-absorbing materials in cosmetic products. The use of graphitic carbon nitride as a UV absorber is also reported (WO2020 / 246715), but graphitic carbon nitride does not contain at least one oxygen atom.

[0004] Cosmetic makeup products are also used to give keratinous substances, such as skin, and in particular facial skin, a desired color appearance. No graphitic carbon nitride that can be used as an ultraviolet-absorbing material and can give keratinous substances a desired color is known. DESCRIPTION OF THE INVENTION

[0005] The object of the present invention is to provide a chemically functionalized graphitic carbon nitride that can provide UV A and / or UV B protection to keratinous materials, in particular to human keratinous material, such as skin, and to keratin fibers, such as hair. Another object of the present invention is to provide a carbon nitride having color variations that allow the composition to be adjusted to the desired shade for any application such as than cosmetic or paint products or as fillers, especially in plastics.

[0006] Thus, the main object of the invention is the use of graphitic carbon nitride as a cosmetic or paint product or as fillers in plastics and, preferably, as a sunscreen, in particular as a UVA and / or UVB absorber.

[0007] The above-mentioned object of the present invention is achieved by a graphitic carbon nitride containing, in particular, at least one oxygen atom (preferably at least one hydroxy group and / or a nitroso group and / or an N-oxide group and / or N-hydroxy (N-OH)). According to one embodiment, the graphitic carbon nitride contains at least one oxygen atom, preferably the oxygen atom(s) is / are bonded to one or more nitrogen atoms, in particular to form a nitroso (-NO) and / or N-oxide group.

[0008] The graphitic carbon nitride of the invention contains at least one heptazine motif in the structure, said structure containing at least one oxygen atom. Said heptazine is preferably represented by formula (I), its salts and its solvates such as hydrates as defined hereinafter.

[0009] According to one embodiment of the invention, the graphitic carbon nitride of the invention contains one or more hydroxy (OH) groups in the structure.

[0010] According to one embodiment, the graphitic carbon nitride contains one or more nitroso (NO) groups.

[0011] According to one embodiment, the graphitic carbon nitride contains one or more N-oxide groups.

[0012] According to one embodiment, the graphitic carbon nitride contains one or more N-OH groups.

[0013] According to one embodiment of the invention, the graphitic carbon nitride of the invention contains one or more carboxy groups in the structure.

[0014] According to a particular embodiment of the invention, the quantity of oxygen atoms in the graphitic carbon nitride is in the range of 0.1 to 10 atomic %, preferably from 0.5 to 7.5 atomic %, and more preferably from 1.0 to 5.0 atomic %, relative to the total atomic quantity of the graphitic carbon nitride of the invention.

[0015] In particular, graphitic carbon nitride has a porous structure.

[0016] Graphitic carbon nitride can have a yellowing index ranging from 5 to 50, preferably from 10 to 45, and more preferably from 15 to 40.

[0017] Graphitic carbon nitride can have an initial absorption front value ranging from 390 to 480 nm, preferably from 400 to 450 nm.

[0018] The present invention also relates to a process for manufacturing graphitic carbon nitride according to the present invention, comprising at least 2 steps: i. the preparation of at least one precursor compound; and ii. heating at least one precursor compound to 450 °C or more for at least 1 minute.

[0019] It being understood that the heating of ii) in the process is carried out in the presence of oxygenated species, such as O2 (in particular with an oxygen flux) and / or humidity.

[0020] The present invention also relates to a composition, preferably a cosmetic composition for keratinous substances, such as skin, in particular a sunscreen composition, comprising graphitic carbon nitride containing at least one oxygen atom as defined herein before and herein after.

[0021] The composition may not include TiO2 or ZnO, or may include TiO2 and / or ZnO in an amount of 5% by weight or less, more preferably 1% by weight or less, relative to the total weight of the composition.

[0022] The present invention also relates to a method, preferably a cosmetic method, for treating keratinous material, in particular human keratinous material such as skin, or keratin fibers such as hair, by applying to said material the composition according to the present invention. Brief description of the drawings

[0023] [Fig.1] Fig.1 represents an XRD diagram of graphitic carbon nitride according to Example 2 of the present invention.

[0024] [Fig.2] Fig.2 represents the absorption spectra obtained by measuring the diffuse UV-vis reflectance of the graphitic carbon nitride powder as synthesized according to examples 1 to 7.

[0025] [Fig.3] Fig.3 represents the absorption spectrum of the liquid sample containing 0.1 wt% of graphitic carbon nitride according to Example 9 suspended in water.

[0026] [Fig.4] Fig.4 represents a relationship between the concentration of oxygen atoms (% at.) in graphitic carbon nitride and the measured initial absorption front value (a) and the measured yellowing index (b).

[0027] [Fig.5] Fig.5 represents a model of an optimized crystal structure (left) and electronic states (right) of the heptazine-motif graphitic carbon nitride of the present invention.

[0028] [Fig.6] Figures 6(A) and 6(B) represent models of crystal structures optimized (left) and electronic states (right) of heptazine motif graphitic carbon nitride. Best embodiment of the invention

[0029] After extensive research, the inventors unexpectedly discovered that incorporating an organic functional group into graphitic carbon nitride can produce a desired color appearance suitable for various products, and thus finalized the invention.

[0030] Thus, the present invention relates mainly to the use of a graphitic carbon nitride containing at least one oxygen atom as cosmetic or paint products or as fillers in plastics and preferably as a sunscreen.

[0031] The graphitic carbon nitride according to the present invention can exhibit UV A and / or B absorption properties and a desired color, such as a white to yellow appearance, and is therefore useful as a UV A and / or B absorber for various products, as it can impart a desired coloring property and an attractive appearance to products. In particular, the graphitic carbon nitride of the present invention is very useful as a UV A and / or B absorber for cosmetic products, as it can provide keratinous substances, such as skin, with UV protection and a desired color tone that contributes to better color management.

[0032] The present invention will be described in detail below. [Use]

[0033] The present invention relates mainly to the use of the graphitic carbon nitride of the present invention as a paint active, a pigment, a plastics filler, a cosmetic active and / or a sunscreen, such as a UVA and / or B absorber.

[0034] In one embodiment, the present invention relates to the use of a graphitic carbon nitride containing at least one oxygen atom, as a UV A and / or B absorber, in order to protect products against damage caused by UV A and / or B radiation. For example, the UV A and / or B absorber of the present invention can be used in paints, plastics, coatings and cosmetics.

[0035] Since the graphitic carbon nitride of the present invention can exhibit a desired color appearance, such as a white to yellow color, the use of the present invention can yield products requiring a desired coloring property and an attractive appearance. Furthermore, cosmetic compositions can give keratinous substances, such as skin, protection against UV A and / or B and a desired color tone, when graphitic carbon nitride is used in cosmetic compositions.

[0036] The graphitic carbon nitride of the present invention will be described in detail below. [Graphitic carbon nitride]

[0037] The present invention also relates to a graphitic carbon nitride containing at least one oxygen atom.

[0038] The term "graphitic" in graphitic carbon nitride here means that the carbon nitride has a planar structure similar to that of graphite. Thus, the graphitic carbon nitride of the present invention has a layered or sheet-like structure.

[0039] The graphitic carbon nitride of the present invention may comprise at least one heptazine motif. In this patent application, the heptazine motif refers to a condensed heterocycle consisting of three unsaturated heterocycles containing C and N atoms (triazine), represented by C6N7, it being understood that at least one of the triazines of at least one heptazine motif contains at least one oxygen atom, and may also contain one hydrogen atom. Preferably, the heptazine motif contains between 3 and 6 double bonds, more preferably 6 conjugated double bonds. Thus, the graphitic carbon nitride of the present invention may have a heptazine-based monolayer structure. The graphitic carbon nitride of the present invention may comprise at least one heptazine motif, at least one triazine motif, and one of their combinations. Said heptazine motif may bear a substituent or a group on the carbon atom.The substituent in question can be oxygenated groups, such as carboxyl, carbonyl, nitroso, nitro, hydroxy, and alkoxy groups, providing additional or staggered levels of occupied and / or unoccupied states. The presence of the heptazine motif can be determined by X-ray diffraction (XRD) analysis, Fourier transform infrared (FT-IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy.

[0040] In one embodiment of the present invention, the graphitic carbon nitride of the present invention has a stacked structure of superimposed graphitic carbon nitride sheets. In other words, the graphitic carbon nitride of the present invention can have a multilayered sheet structure of graphitic carbon nitride. The stacked structure of the graphitic carbon nitride sheets can be determined by X-ray diffraction (XRD) analysis and nuclear magnetic resonance (NMR) spectroscopy analysis.

[0041] The graphitic carbon nitride of the present invention is composed of carbon (C) atoms, nitrogen (N) atoms, hydrogen (H) atoms, and oxygen (O) atoms. Preferably, the graphitic carbon nitride of the present invention consists of, or essentially consists of, carbon (C) atoms, nitrogen (N) atoms, hydrogen (H) atoms, and oxygen (O) atoms.

[0042] The graphitic carbon nitride of the present invention contains at least one oxygen atom in its structure. The amount of oxygen atoms in the graphitic carbon nitride is not particularly limited, but is generally 0.1 atomic percent or more, preferably 0.5 atomic percent or more, and more preferably 1.0 atomic percent or more, and / or may be 10 atomic percent or less, and preferably 7.5 atomic percent or less, and more preferably 5.0 atomic percent or less, relative to the total atomic amount of the graphitic carbon nitride. The atomic concentration of oxygen atoms in the graphitic carbon nitride can be measured, for example, by a commonly known elemental analysis.

[0043] The quantity of oxygen atoms in the graphitic carbon nitride can range from 0.1 to 10 atomic %, preferably from 0.5 to 7.5 atomic %, and more preferably from 1.0 to 5.0 atomic %, relative to the total atomic quantity of the graphitic carbon nitride.

[0044] The graphitic carbon nitride of the present invention comprises at least one nitroso group (-N=O). Thus, the at least one oxygen atom included in the graphitic carbon nitride of the present invention originates from the nitroso group present in the graphitic carbon nitride. The presence of the nitroso group in the graphitic carbon nitride can be measured, for example, by time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0045] The graphitic carbon nitride of the present invention may comprise at least one hydroxyl group (-OH), in addition to the nitroso group (-NO). In other words, the graphitic carbon nitride of the present invention may comprise at least one nitroso group (-NO) and at least one hydroxyl group (-OH) in combination. Thus, the at least one oxygen atom included in the graphitic carbon nitride of the present invention may also originate from the hydroxyl group present in the graphitic carbon nitride. The presence of the hydroxyl group in the graphitic carbon nitride can be measured, for example, by time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0046] The graphitic carbon nitride of the present invention may have a porous structure. More specifically, the graphitic carbon nitride of the present invention may have a nanoporous structure. The pores may exist on the structure in

[0047] layers of graphitic carbon nitride between the heptazine motifs and the triazine motifs. The heptazine motif is preferably represented by formula (I), its salts and its solvates such as hydrates: Ri (I)

[0048] In formula (I), R1, R2, and R3, whether identical or different, represent: i. a hydrogen atom, ii. a halogen atom, iii. an oxygenated group such as a carboxy, nitro or nitroso group, iv. a saturated or unsaturated, linear or branched acyclic, and / or cyclic, aromatic or non-aromatic hydrocarbon chain containing from 1 to 10 carbons, said hydrocarbon chain being potentially interrupted by one or more heteroatoms such as O, S, N or N(O); v. a hydroxy, vi. an amino R4R5N-, in which R4 and R5, identical or different, represent a hydrogen atom, an alkyl group (in C1-C6) or another monovalent heptazine group, preferably a monovalent heptazine group (II) pi in which R1 and R2 are such as defined here

[0049]

[0050] previously; vii. R4R5 N(O)-, in which R4 and R5, whether identical or different, are as defined herein previously; and viii. R4 -N(O)- or ; in which R4 is such as defined here previously ; it being understood that: - at least one of the radicals R1, R2 or R3 represents v) a hydroxy group, more preferably RI represents v) a hydroxy group and R2 and R3, identical or different, preferably identical, represent iii) a nitroso group chosen from vi) to viii), more preferably viii), and

[0051] - one or more nitrogens in the rings can be oxidized (N-oxide or N-OH).

[0052] The ii) halogen can be chosen from Cl and Br.

[0053] The iii) hydrocarbon chain may be a saturated or unsaturated hydrocarbon chain, preferably saturated, linear acyclic or branched, preferably linear acyclic. The iii) hydrocarbon chain may contain from 1 to 6, preferably from 1 to 4, carbon atoms. Thus, the iii) hydrocarbon chain may be a saturated, linear, acyclic hydrocarbon chain containing from 1 to 6, preferably from 1 to 4, carbon atoms, which may be interrupted by one or more heteroatoms such as O, S, N, or N(O).

[0054] More preferably, R1, R2, and R3, identical or different, represent an atom or a group chosen from i) a hydrogen, v) a hydroxy, vi) an amino R4R5N-, in which R4 and R5, identical or different, represent a hydrogen atom, or another monovalent heptazine group (II) in which R1 and R2 are as defined herein above; and viii) a nitroso R4-N(O)- in which R4 is as defined herein above.

[0055] Preferably, at least one of the radicals R1, R2 or R3 represents v) a hydroxy group.

[0056] Preferably, the graphitic carbon nitride according to the present invention contains at least one heptazine motif represented by formula (I), its salts and its solvates such as hydrates as defined hereinafter, which in turn bears a succession of heptazine groups (II) via groups vi) to viii), in particular vi) or viii), of R1, R2, and / or R3, and preferably at least one of the radicals R1, R2 or R3 represents v) a hydroxy group.

[0057] According to one embodiment of the invention, the graphitic carbon nitride contains a succession of heptazine motifs consisting of condensed tri-s-triazine (one ring of formula (I) and two rings of formula (II), sub-motifs coupled by amino groups vi) or nitroso groups vii) or vii), or better viii).

[0058] The graphitic carbon nitride according to the present invention may have a characteristic porous structure exhibiting a large pore volume with a specific pore diameter. For example, the graphitic carbon nitride according to the present invention may have a pore volume greater than 0.0006 cm³ / g, 0.0010 cm³ / g, 0.0020 cm³ / g, 0.0030 cm³ / g, or 0.0040 cm³ / g derived from pores having a specific pore diameter. Furthermore, the graphitic carbon nitride according to the present invention may have a pore volume greater than 0.0006 cm³ / g, 0.0010 cm³ / g, 0.0020 cm³ / g, 0.0030 cm³ / g, or 0.0040 cm³ / g, derived from a first type of pore having a pore diameter specific in the range of 1 nm or more and less than 15 nm, and derived from a second type of pore having a specific pore diameter in the range of 15 nm or more, for example 20 nm or more, to 50 nm or less.

[0059] The quantity of pores having a specific pore diameter included in the graphitic carbon nitride can be determined using the Barrett-Joyner-Halenda (BJH) method for the pore size distribution curves obtained.

[0060] The graphitic carbon nitride of the present invention can exhibit a variety of color appearances, which are suitable and desirable for cosmetic products. For example, the color of the graphitic carbon nitride is chosen from white, pale yellow, and yellow. In preferred embodiments of the present invention, the graphitic carbon nitride can exhibit a yellowish color that can impart better tone management to keratinous substances, such as skin, particularly facial skin.

[0061] The yellowing of graphitic carbon nitride can be defined by a yellowing index, which is an index of yellow color. The yellowing index can be measured using a UV-Vis diffuse reflectance spectrometer. The yellowing index of graphitic carbon nitride can range from 5 to 50, preferably from 10 to 45, and more preferably from 15 to 40. In some embodiments of the present invention, the graphitic carbon nitride has a yellowing index of 20 or more, preferably 25 or more, and more preferably 30 or more. A higher yellowing index indicates a more yellowish appearance of the graphitic carbon nitride.

[0062] The graphitic carbon nitride of the present invention may exhibit UV-A and / or UV-B absorption properties. Preferably, the graphitic carbon nitride exhibits absorption in two regions of UV-B and UV-A rays. UV-B rays here refer to UV rays with a wavelength between 280 and 320 nm. UV-A rays here refer to UV rays with a wavelength between 320 and 400 nm.

[0063] The UV absorption property of the graphitic carbon nitride of the present invention can be represented by an initial absorption front value (nm). The initial absorption front value can be defined as a wavelength (nm) located at the intersection of a straight line drawn to fit a region where an absorbance curve drops sharply on a shorter wavelength side of an absorbance curve, and a straight line drawn to fit an absorbance curve in a wavelength range from 500 to 550 nm, where the absorbance curve is constantly low.

[0064] Example 7 of [Fig. 2] illustrates an example of the initial absorption front value of 407 nm, which is a wavelength at the intersection of (1) the straight line plotted to fit a region where the absorbance curve drops sharply on a shorter wavelength side of the absorbance curve, and (2) the straight line plotted to fit the absorbance curve in the wavelength range of 500 to 550 nm.

[0065] An absorption curve in the ultraviolet and visible light range can be measured, for example, by ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy. A higher initial absorption front value means that the wavelength of the rays that graphitic carbon nitride can filter is longer.

[0066] The graphitic carbon nitride of the present invention may have an initial absorption front value of 390 nm or more, preferably 400 nm or more, and generally 480 nm or less, preferably 450 nm or less.

[0067] The graphitic carbon nitride of the present invention can have an initial absorption front value ranging from 390 to 480 nm, preferably from 400 to 450 nm.

[0068] In certain embodiments of the present invention, the graphitic carbon nitride has an initial absorption front value of 410 nm or more, preferably 415 nm or less, and more preferably 420 nm or more.

[0069] The graphitic carbon nitride of the present invention may or may not be surface treated with a surface treatment agent.

[0070] Figure 5 represents an optimized crystal structure (left) and electronic states (right) of the heptazine-motif graphitic carbon nitride of the present invention. In this modeled structure, one of the nitrogen atoms (labeled N97) forms the -N(O) group. The occupied and unoccupied O2p and N2p energy levels from the -N(O) group appear in the energy region slightly below the middle of the base band gap and near the top of the valence band. In particular, the contribution of the unoccupied energy level to light absorption will lead to absorption in the visible wavelength range, resulting in the characteristic yellow coloration.

[0071] Furthermore, Figures 6(A) and 6(B) represent optimized crystal structures (left) and electronic states (right) of heptazine-motif graphitic carbon nitride. In the modeled structure (A), one of the nitrogen atoms (labeled N97) is bonded to the -OH group and to two carbon atoms of the C6N7 structures at the edge of the heptazine motifs. The nitrogen atom at a similar site without functionalization with an -OH group is labeled N123. In the modeled structure (B), one of the nitrogen atoms (labeled N128) is bonded to the -OH group and to a proton. The nitrogen atom at a similar site without functionalization with an -OH group and without a proton is labeled N121. The highest occupied levels of N97 and N128 shift to a higher energy compared to those of the nitrogen atoms at a similar site without functionalization. This Energy shift affects the local electronic structure in a relatively large way and reduces the band gap, as shown in the red circle, which shifts the absorption front to a higher wavelength.

[0072] Without wishing to develop a theory, the mechanism by which graphitic carbon nitride acquires a yellow appearance through functionalization with oxygenated functional groups, such as -N(O) and -OH groups, is proposed by a first-principles calculation using a local density approximation (LDA). [Manufacturing process]

[0073] The present invention also relates to a method for manufacturing the graphitic carbon nitride of the present invention.

[0074] More specifically, the present invention also relates to a process for manufacturing the graphitic carbon nitrides of the present invention, comprising: i. the preparation of at least one precursor compound; and ii. heating at least one precursor compound to 450 °C or more for at least 1 minute.

[0075] Graphitic carbon nitride can be prepared by heating at least one precursor compound of graphitic carbon nitride. One precursor compound can be used as a raw material for the graphitic carbon nitride of the present invention, or two or more precursor compounds can be used in combination.

[0076] The precursor compound may be selected from precursors known to those skilled in the art, for example, urea, thiourea, melamine, guanidine, arginine, cyanamide, dicyandiamide and one of their salts, and combinations thereof (Chem. Rev. 2016, 116, 7159-7329, Ong, WJ; Tan, LL; Ng, YH; Yong, ST; Chai, SP, Catalysts 2019, 9(10), 805, Seong Jun Mun and Soo-Jin Park; https: / / doi.org / 10.3390 / catal9100805). Preferably, the precursor compound is selected from urea, melamine, guanidine, arginine and one of their salts, and combinations thereof.

[0077] The salt of the precursor compound is not particularly limited, but mention may be made of salts with inorganic acids, such as carbonic acid, and HalH, in which Hal represents a halogen atom such as a chloride (hydrochloric acid).

[0078] In a preferred embodiment of the present invention, a single precursor compound is used as a raw material for the preparation of graphitic carbon nitride.

[0079] The heating temperature of at least one precursor compound is at least 450 °C. Preferably, the heating is carried out at 500 °C or more, and more preferably at 525 °C or more.

[0080] The heating time of at least one precursor compound is at least 1 minute. Preferably, the heating time is at least 10 minutes. more preferably of at least 20 minutes, and / or up to 30 hours, and more preferably up to 25 hours.

[0081] The heating of the precursor compound can be carried out in air, in a noble gas, such as argon or helium, or in an inert gas, such as nitrogen. In preferred embodiments of the present invention, the heating of the precursor compound is carried out in air or in argon.

[0082] In a preferred embodiment, the heating process can be carried out in the presence of an oxygenated species, such as O2, humidity, O3, atomic O, and / or ionic oxygen, as an oxidizing agent. Without wishing to elaborate on this, it is estimated that a more porous graphitic carbon nitride can be obtained when heating is carried out in the presence of an oxygenated species. In the preferred embodiment, the heating is carried out in air, or in a noble gas or an inert gas containing oxygenated species.

[0083] In a preferred embodiment, in addition to oxygen from the air, the heating process is carried out in the presence of an oxygenated species, such as O2, humidity, ozone O3, atomic O and / or ionic oxygen, as an oxidizing agent.

[0084] In a preferred embodiment, the heating process is carried out in the presence of the oxygenated species O2, in particular an oxygen flow, and / or humidity. The term "oxygen flow" may mean an oxygen stream in this patent specification.

[0085] Preferably, the oxidizing agent used during the heating step is in gaseous form.

[0086] According to one embodiment, the oxygen source is neither a permanganate salt nor hydrogen peroxide.

[0087] In one embodiment of the present invention, the heating process includes at least two heating steps at the same or different temperatures. Thus, in one embodiment, the heating process may comprise a first heating step of at least one precursor compound at 450 °C or higher for at least 1 minute, followed by a second heating step of at least one precursor compound at 450 °C or higher for at least 1 minute. The temperature for the first heating step and the temperature for the second heating step may be the same or different, but in general, the temperature for the second heating step is greater than or equal to the temperature for the first heating step. The temperature and duration of the first and second heating steps are identical to those described above.

[0088] In one embodiment of the present invention, a cooling step is present between the heating steps. Thus, in one embodiment, the step The cooling phase is included between the first and second heating stages. The temperature for the cooling phase is not specifically limited, but, for example, it is brought down to ambient temperature (approximately 25°C). The duration of the cooling phase is also not specifically limited, but is, for example, from approximately 1 minute to 24 hours. [Composition]

[0089] The present invention also relates to a composition comprising the graphitic carbon nitride of the present invention. Preferably, the composition according to the present invention is a cosmetic composition, in particular a cosmetic composition for keratinous substances, such as skin. In a preferred embodiment, the composition according to the present invention is a sunscreen composition.

[0090] Furthermore, the composition according to the present invention can be used as a paint active, a pigment, a filler for plastics, a cosmetic active and / or a sunscreen, such as a UVA and / or B absorber.

[0091] The composition according to the present invention preferably does not comprise TiO2 or ZnO.

[0092] In another embodiment, the composition according to the present invention comprises TiO2 and / or ZnO in an amount of 5% by weight or less, more preferably 1% by weight or less, relative to the total weight of the composition. The graphitic carbon nitride of the present invention can be used in the composition in place of TiO2 and ZnO, which are known as traditional inorganic UV filters.

[0093] Since the graphitic carbon nitride of the present invention can have a white to yellow colour appearance, the cosmetic composition according to the present invention can give keratinous substances a desired coloured and attractive appearance, as well as a utility in colour management. [Treatment process]

[0094] Another object of the invention is a process or method for treating keratinous material, in particular human keratinous material such as skin, or keratinous fibers such as hair, by applying to said material at least one composition, preferably a cosmetic composition of the invention, as defined herein above.

[0095] Thus, the cosmetic process or method according to the present invention can be a non-therapeutic cosmetic process or method for treating keratinous material. EXAMPLES

[0096] The present invention will be described in more detail by means of examples. However, these examples should not be interpreted as limiting the scope of the present invention. [Preparation]

[0097] Graphitic carbon nitride according to the present invention in powder form has been prepared as described in the following examples 1 to 10. Example 1

[0098] 10 g of urea powder as a precursor compound were subjected to heating at 550 °C in air for 2 hours to obtain a graphitic carbon nitride according to example 1. Example 2

[0099] 10 g of urea powder as a precursor were subjected to heating at 550 °C in air for 1 hour and subsequently heated to 600 °C in air for 30 minutes in air to obtain a graphitic carbon nitride according to example 2. Example 3

[0100] 10 g of urea powder as a precursor compound were subjected to heating at 600 °C in air for 2 hours to obtain a graphitic carbon nitride according to example 3. Example 4

[0101] 10 g of urea powder as a precursor were subjected to heating at 600 °C in air for 2 hours, cooled to room temperature, then heated to 600 °C in air for 1 hour to obtain a graphitic carbon nitride according to example 4. Example 5

[0102] 10 g of urea powder as a precursor compound were submitted three times to a sequential process of (a) heating to 600 °C in air for 1 hour and (b) cooling to room temperature to obtain a graphitic carbon nitride according to Example 5. Example 6

[0103] 10 g of urea powder as a precursor compound were subjected to heating at 600 °C in air for 2 hours, to cooling to room temperature, then twice to a sequential process of (a) heating to 600 °C in air for 1 hour and (b) cooling to room temperature to obtain a graphitic carbon nitride according to Example 6. Example 7

[0104] 12 g of urea powder as a precursor compound were submitted three times to a sequential process of (a) heating at 600 °C in air for 1 hour and (b) cooling to room temperature to obtain a graphitic carbon nitride according to example 7. Example 8

[0105] 10 g of urea powder as a precursor compound were heated between 600 and 605 °C in air for 2 hours to obtain a graphitic carbon nitride according to example 8. Example 9

[0106] 3 g of melamine powder as a precursor compound were subjected to a heating to 550 °C in air for 5 hours to obtain a graphitic carbon nitride according to example 9. Example 10

[0107] 20 g of guanidine carbonate powder as a precursor were submitted to heating at 600 °C in air for 2 hours to obtain a graphitic carbon nitride according to example 10. [Assessment]

[0108] (Crystal structure)

[0109] The crystal structure of each of the graphitic carbon nitrides was characterized by X-ray diffraction (XRD) analysis. On the XRD diagram, the 13° peak was assigned to the (100) plane of heptazine-motif graphitic carbon nitride; the 27° peak was assigned to the (002) plane of the c-axis in stacked sheets of graphitic carbon nitride. [Fig. 1] shows an XRD diagram of graphitic carbon nitride according to Example 2 as a representative example.

[0110] According to XRD analysis of graphitic carbon nitride from each of Examples 1 to 10, it was confirmed that each of the graphitic carbon nitrides according to Examples 1 to 10 had multilayered sheets of graphitic carbon nitride with heptazine motifs.

[0111] (Analysis of elemental composition)

[0112] The elemental composition of each of the graphitic carbon nitrides was estimated by a CNHO elemental analysis based on the combustion of the samples.

[0113] (Analysis by time-of-flight secondary ion mass spectrometry (TOF-SIMS))

[0114] A TOF-SIMS analysis was performed to determine whether functional groups are present in each of the graphitic carbon nitrides. For the TOF-SIMS analyses, TOF.SIMS 5 (ION-TOF GmbH, Germany) was used. The primary ion irradiated was 209Bi3++.

[0115] On the TOF-SIMS spectra (analyzed surface: 90,000 pm2) of Example 2, the intensity of m / z=17 attributable to the OH- ion was 1460 and that of m / z=30 attributable to NO- was 92.

[0116] On the TOF-SIMS spectra (analyzed area: 90,000 pm2) of Example 4, the intensity of m / z=17 attributable to the OH- ion was 764 and that of m / z=30 attributable to NO- was 59.

[0117] On the TOF-SIMS spectra (analyzed area: 40,000 pm2) of Example 8, the intensity of m / z=17 attributable to the OH- ion was 1195 and that of m / z=30 attributable to NO- was 86.

[0118] On the TOF-SIMS spectra (analyzed area: 40,000 pm2) of Example 9, the intensity of m / z=17 attributable to the OH- ion was 1342 and that of m / z=30 attributable to NO- was 88.

[0119] On the TOF-SIMS spectra (analyzed area: 40,000 pm2) of Example 10, the intensity of m / z=17 attributable to the OH- ion was 1671 and that of m / z=30 attributable to NO- was 73.

[0120] According to the TOF-SIMS analysis of the graphitic carbon nitride of each of the examples 1 to 10, it was confirmed that each of the graphitic carbon nitrides comprised nitroso groups and hydroxy groups.

[0121] (UV absorption property and yellowing index)

[0122] The light absorption performance of each of the graphitic carbon nitrides in the ultraviolet and visible light wavelength range was evaluated by ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy (UV2500PC, Shimadzu Corporation) coupled to an integrating sphere.

[0123] The UV-vis absorption spectra of an aqueous dispersion containing 0.1 wt% of each of the graphitic carbon nitrides (medium: water) in a fine quartz cell (two transparent sides, 2 mm (optical path length) x 10 mm x H45 mm, Tokyo Garasu Kikai Co., Ltd.) were collected using a UV-Visible spectrophotometer (V750, Jasco Inc.) coupled to an integrating sphere.

[0124] The initial adsorption front was estimated from the diffuse UV / vis reflectance spectrum of each sample.

[0125] Fig. 2 represents the absorption spectra obtained by measuring the diffuse UV-vis reflectance of the graphitic carbon nitride powder as synthesized according to Examples 1 to 7. All the graphitic carbon nitrides exhibited absorption in the UV range, in which the wavelength is less than 400 nm.

[0126] Figure 3 represents the absorption spectrum of the liquid sample containing 0.1 wt% of graphitic carbon nitride according to Example 9 suspended in water, as a representative example. The aqueous suspension exhibited absorption in the UV wavelength range, which is less than 400 nm.

[0127] The yellowing index, which is an index of the yellow color, was also evaluated from the diffuse UV-vis reflectance spectrum of each powder sample. The calculation of the yellowing index and the whiteness value was performed using the Shimadzu software installed on the instrument, where illuminant C was used as the standard illuminant and a viewing angle was set to 10°. The standard white BaSO4 plate was used as a reference.

[0128] The results are summarized in Table 1 below. In addition, the relationship between the concentration of oxygen atoms (% at.) in the graphitic carbon nitride and the initial absorption front value is shown in [Fig.4](a) and the relationship between the concentration of oxygen atoms (% at.) in the graphitic carbon nitride and the measured yellowing index is shown in [Fig.4](b).

[0129] [Tables 1] Elemental Composition Atomic Oxygen Concentration (% at.) Initial Absorption Front Value (nm) Yellowing Index Ex. 1 C3N4j3gH2j420oj343 3.4 431 32.13 Ex. 2 C3N436H232O0355 3.5 437 38.76 Ex. 3 C3N4j37H2j070o.259 2.7 426 32.54 Ex. 4 C3N437H1.94(0.185) 1.9 406 18.63 Ex. 5 C3N4.38Hi.94O0.121 1.3 407 19.21 Ex. 6 C3N4.37Hi.94Oq.192 2.0 414 27.55 Ex. 7 C3N4,36Hi,930o,114 1.2 408 23.54

[0130] Table 1 and [Fig.4](a) show that there is a trend whereby the greater the quantity of oxygen atoms, the higher the initial absorption front value of graphitic carbon nitride.

[0131] Furthermore, the graph in [Fig. 4](b) clearly shows that a higher concentration of oxygen atoms (% at.) in graphitic carbon nitride produces a higher yellowing index for the graphitic carbon nitride. This indicates that the higher the concentration of oxygen atoms in the graphitic carbon nitride, the more yellowish the graphitic carbon nitride appears.

[0132] Thus, the graphitic carbon nitride according to the present invention has the very remarkable effect that it is possible to modify and design the color appearance desired as well as the UV absorption property by functionalizing graphitic carbon nitride with a nitroso group as an oxygenated functional group.

[0133] Consequently, it can be concluded that the graphitic carbon nitride of the present invention is very useful as a UV absorber for various products, as it can impart to the products a desired coloring property and an attractive appearance. In particular, the graphitic carbon nitride of the present invention is very useful as a UV absorber for cosmetic products, as it can provide keratinous substances, such as skin, with UV protection and a desired color tone that contributes to better color management.

Claims

Demands

1. Use of a graphitic carbon nitride containing at least one oxygen atom, as a paint active, as a pigment, as a filler, in particular for plastics, or as a cosmetic active.

2. Use of a graphitic carbon nitride according to claim 1, as a cosmetic product, preferably as a sunscreen.

3. Use of graphitic carbon nitride according to any one of the preceding claims, wherein the graphitic carbon nitride comprises at least one heptazine motif in the structure, preferably having at least one hydroxy group, one nitroso group, one N-oxide group and / or one N-hydroxy (N-OH) group, preferably having at least one hydroxy group and at least one nitroso group.

4. Use of graphitic carbon nitride according to claim 3, wherein the heptazine motif is represented by formula (I), its salts and its solvates such as the hydrates: R* ® N^NN^N^NAA A. R°' N' N in formula (I): R1, R2, and R3, identical or different, represent: i) a hydrogen atom, ii) a halogen atom, iii) an oxygen group such as a carboxy, nitro or nitroso group, iv) a saturated or unsaturated, acyclic linear or branched, and / or cyclic, aromatic or non-aromatic hydrocarbon chain, containing from 1 to 10 carbons, said hydrocarbon chain being potentially interrupted by one or more heteroatoms such as O, S, N or N(O); v) a hydroxy, vi) an amino R4R5N-, in which R4 and R5, identical or different, represent a hydrogen atom, an alkyl group (in Ci-C6) or another monovalent heptazine group, preferably a monovalent heptazine (II) psi group in which R1 and

5.

6. R2 are as defined here previously; vii) R4R5 N(O)-, in which R4 and R5, whether identical or different, are as defined herein previously; and viii) R4 -N(O)- or ; in which R4 is such as defined here previously ; a. it being understood that: - at least one of the radicals R1, R2 or R3 represents v) a hydroxy group, more preferably R1 represents v) a hydroxy group and R2 and R3, identical or different, preferably identical, represent iii) a nitroso group chosen from vi) to viii), more preferably viii), and - one or more nitrogens in the rings can be oxidized (N-oxide or N-OH). Use of graphitic carbon nitride according to claim 4, wherein R1, R2, and R3, identical or different, represent an atom or group selected from i) a hydrogen, v) a hydroxy, vi) an amino R4R5N-, in which R4 and R5, identical or different, represent a hydrogen atom, or another monovalent heptazine group (II) in which R1 and R2 are as defined herein above; and viii) a nitroso R4-N(O)- in which R4 is as defined herein above; preferably at least one of the radicals R1, R2 or R3 represents v) a hydroxy group. Use of graphitic carbon nitride according to claim 4 or 5, wherein the heptazine motif bears a succession of heptazine(II) groups via any one of groups vi) to viii), in particular via groups vi) or viii) in R1, R2 and / or R3 as defined in claim 4 or 5, and preferably at least one of the radicals R1, R2 or R3 represents v) a hydroxy group.

7. Use of graphitic carbon nitride according to any one of the preceding claims, wherein the graphitic carbon nitride has a yellowing index from 5 to 50, preferably from 10 to 45, and more preferably from 15 to 40.

8. Graphitic carbon nitride containing at least one oxygen atom, wherein the oxygen atom is present in at least one nitroso (NO) group, said graphitic carbon nitride being used as a paint active, as a pigment, as a filler, in particular for plastics, or as a cosmetic active.

9. A process for preparing graphitic carbon nitride as defined in claim 8, comprising: i. the preparation of at least one precursor compound; and ii. heating the at least one precursor compound to 450 °C or more for at least 1 minute; preferably heating ii) is carried out in the presence of oxygenated species such as O2, moisture, O3, atomic O and / or ionic oxygen, as an oxidizing agent; preferably, the oxidizing agent used during the heating step is in gaseous form; more preferably, the oxygenated species are neither a permanganate salt nor hydrogen peroxide.