Graphitic carbon nitride containg one oxygen atom as sunscreen, paint, or filler product

Abstract

The present invention mainly relates to a use of graphitic carbon nitride containing at least one oxygen atom, as a paint active, a pigment, a filler of plastics, a cosmetic active, and / or a sunscreen, such as a UVA and / or B absorber. The graphitic carbon nitride can exhibit a UVA and / or B absorption property and white to yellow colors and thus is useful as a UV absorber for various products which requires a coloring property and attractive appearance.

Description

[0001] DESCRIPTION

[0002] TITLE OF INVENTION

[0003] GRAPHITIC CARBON NITRIDE CONTAING ONE OXYGEN ATOM AS SUNSCREEN, PAINT, OR FILLER PRODUCT

[0004] TECHNICAL FIELD

[0005] The present invention mainly relates to a graphitic carbon nitride containing at least one oxygen atom (especially functionalized with hydroxyl groups, preferably a graphitic carbon nitride functionalized with N-oxide, or nitroso groups and hydroxyl groups) for use as ultraviolent (UVA and / or UVB) absorbing material in cosmetic or paint products or as fillers especially in plastics.

[0006] BACKGROUND ART

[0007] A UV protecting effect is one of key factors for cosmetic products. Graphitic carbon nitride, which is an inorganic compound, is known for to exhibit UV absorbing property. Some documents relating to graphitic carbon nitride have previously been reported.

[0008] For example, CN104801326A discloses a surface-hydroxylated nanoporous carbon nitride photocatalytic materials. However, this document is silent about use of carbon nitrides as ultraviolent absorbing materials in cosmetic products. It is also reported the use of graphitic carbon nitride as UV absorbers (WO2020 / 246715), but the graphitic carbon nitride does not contain at least one oxygen atom.

[0009] Moreover, make-up cosmetic products are used in order to provide keratinous substances, such as skin, in particular facial skin, with a desired color appearance. No graphitic carbon nitride, which can be used as an ultraviolent absorbing material and can provide keratinous substances with a desired color, is known.

[0010] DISCLOSURE OF INVENTION

[0011] The objective of the present invention is to provide a chemically-functionalized graphitic carbon nitride, which can provide the keratinous materials especially human keratin material, such as skin, and keratin fibers such as hair with UV A and / or B protection. Another object of the present invention is to provide carbon nitride having color variations that allow the composition to be adjusted to the desired tone for any application such as cosmetic or paint products or as fillers especially in plastics.

[0012] Thus the main object of the invention is the use of graphitic carbon nitride as cosmetic or paint products or as fillers in plastics and preferably as sunscreen, in particular UVA and / or B absorber.

[0013] The above objective of the present invention is achieved by a graphitic carbon nitride especially containing at least one oxygen atom (preferably at least one hydroxy group and / or nitroso group and / or 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 bound to one or more nitrogen atom(s) particularly to form a nitroso (-NO) and / or N-Oxide group.

[0014] The graphitic carbon nitride of the invention contains at least one heptazine unit in the structure, the said structure contains at least one oxygen atom. The said heptazine is preferably represented by formula (I), its salts and its solvates such as hydrates as defined herein after.

[0015] According to an embodiment of the invention the graphitic carbon nitride of the invention contains one or more hydroxy (OH) group(s) in the structure.

[0016] According to one embodiment, the graphitic carbon nitride contains at one or more nitroso (NO) group (s).

[0017] According to one embodiment, the graphitic carbon nitride contains one or more N-Oxide group(s).

[0018] According to one embodiment, the graphitic carbon nitride contains one or more N-OH group(s).

[0019] According to an embodiment of the invention, the graphitic carbon nitride of the invention contains one or more carboxy group(s) in the structure.

[0020] According to one particular embodiment of the invention the amount of the oxygen atoms in the graphitic carbon nitride is within the 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 amount of the graphitic carbon nitride of the invention.

[0021] Particularly the graphitic carbon nitride has a porous structure.

[0022] The graphitic carbon nitride may have a yellowness index ranging from 5 to 50, preferably from 10 to 45, and more preferably from 15 to 40.

[0023] The graphitic carbon nitride may have an onset absorption edge value ranging from 390 to 480 nm, preferably from 400 to 450 nm.

[0024] The present invention also relates to a process for manufacturing the graphitic carbon nitride according to the present invention, comprising at least 2 steps: i) preparing at least one precursor compound; and ii) heating the at least one precursor compound at 450 °C or more for at least 1 minute.

[0025] Being understood that the ii) heating in the process is carried out in a presence of oxygencontaining species, such as Oa (especially with oxygen flux) and / or humidity.

[0026] The present invention also relates to a composition, preferably a cosmetic composition for keratinous substances, such as skin, in particular a sunscreen composition, comprising the graphitic carbon nitride containing at least one oxygen atom as defined herein before and herein after.

[0027] The composition may not comprise TiCh or ZnO, or may comprise TiCh 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 present invention also relates to a process, preferably a cosmetic process, for treating keratin material, especially human keratin material such as skin, or keratin fibers such as hair, by application on the said material the composition according to the present invention.

[0028] BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 shows XRD pattern of graphitic carbon nitride according to Example 2 of the present invention.

[0030] Figures 2 shows absorption spectra obtained via UV-vis diffuse reflectance measurement of the as-synthesized powder of graphitic carbon nitride according to Examples 1 to 7.

[0031] Figure 3 shows absorption spectrum of the liquid sample suspended with 0.1% by weight of graphitic carbon nitride according to Example 9 in water.

[0032] Figure 4 shows a relationship between concentration of oxygen atoms (at.%) in the graphitic carbon nitride and the measured onset absorption edge value (a) and the measured yellowness index (b).

[0033] Figure 5 shows a model of an optimized crystalline structure (left) and electronic states (right) of the graphitic carbon nitride with heptazine units of the present invention.

[0034] Figure 6(A) and 6(B) show models of optimized crystalline structures (left) and electronic states (right) of the graphitic carbon nitride with heptazine units.

[0035] BEST MODE FOR CARRYING OUT THE INVENTION

[0036] After diligent research, the inventors have surprisingly found that an incorporation of an organic functional group into graphitic carbon nitride can produce a desired color appearance which is suitable for various products, and thus completed the invention.

[0037] Thus, the present invention mainly relates to a use of graphitic carbon nitride containing at least one oxygen atom as cosmetic or paint products or as fillers in plastics and preferably as sunscreen.

[0038] The graphitic carbon nitride according to the present invention can exhibit a UV A and / or B absorption property and a desired color, such as white to yellow color appearance, and thus is useful as a UV A and / or B absorber for various products, since it can provide products with a desired coloring property and attractive appearance. In particular, the graphitic carbon nitride of the present invention is very useful as a UV A and / or B absorber for cosmetic products, since it can provide the keratinous substances, such as skin, with UV protection and a desired color tone which contributes to improved color management.

[0039] Hereafter, the present invention will be described in a detailed manner.

[0040] [Use]

[0041] The present invention mainly relates to a use of the graphitic carbon nitride of the present invention as a paint active, a pigment, a filler of plastics, a cosmetic active, and / or a sunscreen, such as a UVA and / or B absorber.

[0042] In one embodiment, the present invention relates to 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 from damages caused from 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.

[0043] Because the graphitic carbon nitride of the present invention can exhibit a desired color appearance, such as white to yellow color appearance, the use of the present invention can provide products requiring a desired coloring property and attractive appearance. In addition, cosmetic compositions can provide the keratinous substances, such as skin, with UV A and / or B protection and a desired color tone, when the graphitic carbon nitride is used in the cosmetic compositions.

[0044] The graphitic carbon nitride of the present invention will be described in a detailed manner below.

[0045] [Graphitic Carbon Nitride]

[0046] The present invention also relates to graphitic carbon nitride containing at least one oxygen atom.

[0047] The term "graphitic" in the graphitic carbon nitride here means that the carbon nitride has a planar graphite-like structure. Thus, the graphitic carbon nitride of the present invention has a layered or a sheet structure.

[0048] The graphitic carbon nitride of the present invention may comprise at least one heptazine unit. In the present specification, the heptazine unit means a hetero-fused ring consisting of three unsaturated hetero rings containing C atoms and N atoms (triazine), represented with CeN?, being understood that at least one of triazine of at least one heptazine unit contains at least one oxygen atom, and can contains also hydrogen atom. Preferably the heptazine unit contains between 3 to 6 double bound, more preferably conjugated 6 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 unit, at least one triazine unit, and a combination thereof. The said heptazine unit can bear substituent or group on the carbon atom. The said substituent can be oxygencontaining groups, such as carboxyl, carbonyl, nitroso, nitro, hydroxy, and alkoxy groups, providing additional or shifted levels of occupied and / or unoccupied states. The presence of the heptazine unit can be determined by X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR) analysis, and nuclear magnetic resonance spectroscopy (NMR) analysis.

[0049] In one embodiment of the present invention, the graphitic carbon nitride of the present invention has a stacked structure of layered graphitic carbon nitride sheets. In other words, the graphitic carbon nitride of the present invention may have a multi-layered sheet structure of the 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 spectroscopy (NMR) analysis

[0050] The graphitic carbon nitride of the present invention is composed of carbon atoms (C), nitrogen atoms (N), hydrogen atoms (H), and oxygen atoms (0). Preferably, the graphitic carbon nitride of the present invention consists of or substantively consists of carbon atoms (C), nitrogen atoms (N), hydrogen atoms (H), and oxygen atoms (O). The graphitic carbon nitride of the present invention contains at least one oxygen atom in its structure. The amount of the oxygen atoms in the graphitic carbon nitride is not particularly limited, but in general is 0.1 atomic % or more, preferably 0.5 atomic % or more, and more preferably 1.0 atomic % or more, and / or may be 10 atomic % or less, and preferably 7.5 atomic % or less, and more preferably 5.0 atomic % or less, relative to the total atomic amount of the graphitic carbon nitride. The atomic concentration of the oxygen atoms in the graphitic carbon nitride can be measured by, for example, commonly known elemental analysis.

[0051] The amount of the oxygen atoms in the graphitic carbon nitride may 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 amount of the graphitic carbon nitride.

[0052] 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 is derived from the nitroso group present in the graphitic carbon nitride.

[0053] The presence of the nitroso group in the graphitic carbon nitride can be measured by, for example, time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0054] The graphitic carbon nitride of the present invention may comprise at least one hydroxy group (-OH), in addition to the nitroso group (-NO). In other words, graphitic carbon nitride of the present invention may comprise at least one nitroso group (-NO) and at least one hydroxy group (-OH) in combination. Thus, the at least one oxygen atom included in the graphitic carbon nitride of the present invention may also be derived from the hydroxy group present in the graphitic carbon nitride. The presence of the hydroxy group in the graphitic carbon nitride can be measured by, for example, time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0055] 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 nano-porous structure. The pores may exist on the layer structure of the graphitic carbon nitride between heptazine units and triazine units.

[0056] The heptazine unit is preferably represented by formula (I), its salts and its solvates such as hydrates: in Formula (I), R1, R2, and R3, identical or different, represent: i) a hydrogen atom, ii) an halogen atom, iii) an oxy gen-containing group as carboxy, nitro, or nitroso group, iv) a saturated or unsaturated, acyclic linear or branched, and / or cyclic, aromatic or nonaromatic, hydrocarbon chain containing from 1 to 10 carbon carbons, the said hydrocarbon chain being potentially interrupted by one or more heteroatom such as O, S, N or N(O); v) hydroxy, vi) amino R4R5N-, wherein R4and R5, identical or different, represent a hydrogen atom, (Ci-Ce)alkyl group or another monovalent heptazine group, preferably a monovalent heptazine group wherein R1and R are as defined herein before; vii) R4R5N(O)-, wherein R4and R5, identical or different, are as defined herein before; and viii) R4-N(O)- or ; wherein R4is as defined herein before; it being understood that: at least one of radical R1, R2or R3represents v) a hydroxy group, more preferably R1 represents v) hydroxy group and R2and R3, identical or different, preferably identical, represent iii) nitroso group selected from vi) to viii), more preferably viii), and one or more nitrogen into the cycles can be oxidized (N-oxide, or N-OH).

[0057] The ii) halogen may be selected from Cl and Br.

[0058] The iii) hydrocarbon chain may be a saturated or unsaturated, preferably saturated, acyclic linear or branched, preferably acyclic linear, hydrocarbon chain. The iii) hydrocarbon chain may contain from 1 to 6, preferably 1 to 4 carbon carbons. Thus, the iii) hydrocarbon chain may be a saturated and acyclic linear hydrocarbon chain containing from 1 to 6, preferably 1 to 4 carbon carbons, which can be interrupted by one or more heteroatom such as O, S, N or N(O).

[0059] More preferably R1, R2, and R3, identical or different, represent an atom or group selected from i) a hydrogen, v) a hydroxy, vi) an amino R4R5N-, wherein R4and R5, identical or different, represent a hydrogen atom, or another monovalent heptazine group (II) wherein R1and R2are as defined herein before; and viii) nitroso R4-N(0)- wherein R4is as defined herein before.

[0060] Preferably at least one of radical R1, R2or R3represents v) a hydroxy group.

[0061] Preferably the graphitic carbon nitride according to the present invention contains at least one heptazine unit represented by formula (I), its salts and its solvates such as hydrates as defined herein after, which in turn bears a succession of heptazine groups (II) via the group vi) to viii) especially vi) or viii) of R1, R2, and / or R3and preferably at least one of radical R1, R2or R3represents v) a hydroxy group. According to an embodiment of the invention, the graphitic carbon nitride contains a succession of heptazine units consisting of the condensed tri-s-triazine (one ring of formula (I) and two rings of formula (II) subunits coupled through amino groups vi) or nitroso groups vii) or vii) better viii). .

[0062] The graphitic carbon nitride according to the present invention may have characteristic porous structure having a large pore volume of pores having 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. Also, 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 first type of pores having a specific pore diameter in the range of 1 nm or more and less than 15 nm, and derived from second types of pores having a specific pore diameter in the range of 15 nm or more, for example 20 nm or more, and 50 nm or less.

[0063] The amount of the pores having a specific pore diameter included in the graphitic carbon nitride can be determined by using the Barrett- Joyner-Halenda (BJH) method to the obtained pore-size distribution plots.

[0064] The graphitic carbon nitride of the present invention can show a variety of color appearances, which are suitable and desired for cosmetic products. For example, the color of the graphitic carbon nitride is selected from white, pale yellow, and yellow. In preferred embodiments of the present invention, the graphitic carbon nitride can exhibit yellowish color which can provide the keratinous substance, such as skin, in particular facial skin, with improved tone management.

[0065] The yellowness of the graphitic carbon nitride can be defined by a yellowness index, which is an index of a yellow color. The yellowness index can be measured with a UV-vis diffuse reflectance spectrometer. The yellowness index of the graphitic carbon nitride may 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 exhibits a yellowness index of 20 or more preferably 25 or more, and more preferably 30 or more. The higher yellowness index indicates the more yellowish appearance that the graphitic carbon nitride exhibits.

[0066] The graphitic carbon nitride of the present invention can exhibit a UV A and / or B absorption property. Preferably, the graphitic carbon nitride has the absorption effect against both regions of UV-B and UV-A rays. UV-B rays here means UV rays having a wavelength between 280 to 320 nm. UV-A rays here means UV rays having a wavelength between 320 to 400 nm.

[0067] The UV absorption property of the graphitic carbon nitride of the present invention can be represented by an onset absorption edge value (nm). The onset absorption edge value can be defined with a wavelength (nm) at an intersection of a straight line drawn to fit a region where an absorbance curve drops sharply from a shorter wavelength side of an absorbance curve, and a straight line drawn to fit an absorbance curve in a wavelength range of 500 to 550 nm, where the absorbance curve becomes constantly low. Example 7 in Figure 2 depicts an example of the onset absorption edge value being 407 nm, which is a wavelength at the intersection of the (1) straight line drawn to fit a region where the absorbance curve drops sharply from a shorter wavelength side of the absorbance curve, and the (2) straight line drawn to fit the absorbance curve in the wavelength range of 500 to 550 nm.

[0068] An absorption curve in a range of ultraviolet light and visible light can be measured by, for example, ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy. The higher onset absorption edge value means the longer wavelength of rays the graphitic carbon nitride can filter.

[0069] The graphitic carbon nitride of the present invention may have the onset absorption edge value of 390 nm or more, preferably 400 nm or more, and in general 480 nm or less, preferably 450 nm or less.

[0070] The graphitic carbon nitride of the present invention may have the onset absorption edge value ranging from 390 to 480 nm, preferably from 400 to 450 nm.

[0071] In some embodiments of the present invention, the graphitic carbon nitride has the onset absorption edge value of 410 nm or more, preferably 415 nm or less, and more preferably 420 nm or more.

[0072] The graphitic carbon nitride of the present invention may be surface-treated or may not be surface-treated with a surface treating agent.

[0073] Figure 5 shows an optimized crystalline structure (left) and electronic states (right) of the graphitic carbon nitride with heptazine units of the present invention. In this modeled structure, one of nitrogen atoms (labeled as N97) forms -N(O) group. The levels of occupied and unoccupied states of O2p and N2p originated from -N(O) group appear in the energy region located a little below the middle of basic bandgap region and that located close to the top of valence band. Particularly, contribution of the level of unoccupied state to the light absorption will lead to the absorption in the visible wavelength range, which result in the coloration, such as yellow appearance.

[0074] Also, Figure 6(A) and 6(B) show optimized crystalline structures (left) and electronic states (right) of the graphitic carbon nitride with heptazine units. In the modeled structure (A), one (labeled as N97) of nitrogen atoms is bound to -OH group and two carbon atoms of CeX? structures at the edge of the heptazine units. The nitrogen atom at the similar site without functionalization of -OH group is labeled as N 123. In the modeled structure (B), one (labeled as N128) of nitrogen atoms is bound to -OH group and proton. The nitrogen atom at the similar site without functionalization of -OH group and proton is labeled as N121.

[0075] The occupied highest levels of both N97 and N 128 shift to the higher energy in comparison with those of nitrogen atoms at similar site without functionalization. This energy shift relatively largely affects the local electronic structure and narrows the bandgap as shown in the red circle to shift the absorption edge to the higher wavelength.

[0076] While not wishing to be bound by theory, the mechanism of providing graphitic carbon nitride with yellow color appearance by functionalization of with oxygen-including functional groups, such as -N(O) and -OH groups, is proposed via first-principles calculation using local density approximation (LDA). [Manufacturing Process]

[0077] The present invention also relates to a process for manufacturing the graphitic carbon nitride of the present invention.

[0078] Specifically, the present invention also relates to a process for manufacturing the graphitic carbon nitrides of the present invention, comprising: i) preparing at least one precursor compound; and ii) heating the at least one precursor compound at 450 °C or more for at least 1 minute.

[0079] The graphitic carbon nitride can be prepared by heating at least one precursor compound of the graphitic carbon nitride. One precursor compound may be used as a raw material of the graphitic carbon nitride of the present invention, or two or more precursor compounds may be are used in combination.

[0080] The precursor compound may be selected from the precursor known by one skilled in the art, for example, urea, thiourea, melamine, guanidine, arginine, cyanamide, dicyandiamide, and a salt thereof, and combinations thereof (Chem. Rev. 2016, 116, 7159-7329, Ong, W.J.; Tan, L.L.; Ng, Y.H.; Yong, S.T.; Chai, S.P., 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 a salt thereof and the combination thereof.

[0081] The salt of the precursor compound is not particularly limited, but mention can be made of salts with inorganic acids, such as carbonic acid and HalH wherein Hal represents halogen atom such as chloride (hydrochloric acid).

[0082] In one preferred embodiment of the present invention, only one precursor compound is used as a raw material in the preparation of the graphitic carbon nitride.

[0083] The temperature for heating the at least one precursor compound is at least 450 °C.

[0084] Preferably, the heating is carried out at 500 °C or more, and more preferably at 525 °C or more.

[0085] The period or the heating of the at least one precursor compound is at least 1 minute. Preferably, the period of the heating is at least 10 minutes, more preferably at least 20 minutes, and / or within 30 hours, and more preferably within 25 hours.

[0086] The heating of the precursor compound can be carried out in air, in noble gas, such as argon or helium, or in 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.

[0087] In one preferred embodiment, the heating process may be carried out in a presence of oxygencontaining species, such as Oz, humidity, O3, atomic O, and / or ionic oxygen, as an oxidizing agent. While not wishing to be bound by theory, it is believed that more porous graphitic carbon nitride can be obtained when the heating is carried out in the presence of oxygencontaining species. In the preferred embodiment, the heating is carried out in air, or in noble gas or inert gas including oxy gen-containing species.

[0088] In a preferred embodiment, in addition to oxygen in the air, the heating process is carried out in the presence of oxygen-containing species, such as O2, humidity, ozone O3, O atomic and / or ionic oxygen, as an oxidizing agent.

[0089] In a preferred embodiment, the heating process is carried out in a presence of oxygencontaining species of O2, in particular oxygen flux, and / or humidity. The term "oxygen flux" can mean an oxygen flow in the present specification.

[0090] Preferably the oxidizing agent used during the heating step is in a gas form.

[0091] According one embodiment the oxygen source is neither from permanganate salt nor from hydrogen peroxide.

[0092] 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 the at least one precursor compound at 450°C or more for at least 1 minute, and then a second heating step of the at least one precursor compound at 450 °C or more 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 equal to or greater than the temperature for the first heating step. The temperature and period for the first and second heating steps are as explained above.

[0093] In one embodiment of the present invention, a cooling step is present between heating steps. Thus, in one embodiment, the cooling step is included between the first heating step and the second heating step. The temperature for the cooling step is not particularly limited, but for example, the temperature is cooled to a room temperature (about 25 °C). The period of the cooling step is not particularly limited, but for example is about from 1 minute to 24 hours.

[0094] [Composition]

[0095] The present invention also relates to a composition including 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 one preferred embodiment, the composition according to the present invention is a sunscreen composition.

[0096] Also, the composition according to the present invention can be used as a paint active, a pigment, a filler of plastics, a cosmetic active, and / or a sunscreen, such as a UVA and / or B absorber.

[0097] The composition according to the present invention preferably does not comprise TiCh or ZnO.

[0098] In another embodiment, the composition according to the present invention comprises TiC 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 instead of TiO2 and ZnO, which are known as traditional inorganic UV filters.

[0099] Because the graphitic carbon nitride of the present invention can exhibit white to yellow color appearance, the cosmetic composition according to present invention can provide keratinous substances with a desired colored and attractive appearance, as well as usefulness in color management.

[0100] [Method of treatment]

[0101] Another object to the invention is a method or process for treating keratin material, especially human keratin material such as skin, or keratin fibers such as hair, by application on the said material at least a composition preferably a cosmetic composition of the invention as defined herein before.

[0102] Thus, the method or process according to the present invention can be a cosmetic, non- therapeutical method or process for treating keratin material.

[0103] EXAMPLES

[0104] The present invention will be described in a more detailed manner by way of examples. However, these examples should not be construed as limiting the scope of the present invention.

[0105] [Preparation]

[0106] The graphitic carbon nitride according to the present invention in powder form was prepared in the following Examples 1 to 10.

[0107] Example 1

[0108] 10 g of urea powder as the precursor compound was subjected to heating at 550 °C in air for 2 hours to obtain graphitic carbon nitride according to Example 1.

[0109] Example 2

[0110] 10 g of urea powder as the precursor was subjected to heating at 550 °C in air for 1 hour and subsequent heating at 600 °C in air for 30 minutes in air to obtain graphitic carbon nitride according to Example 2.

[0111] Example 3

[0112] 10 g of urea powder as the precursor compound was subjected to heating at 600 °C in air for 2 hours to obtain graphitic carbon nitride according to Example 3.

[0113] Example 4

[0114] 10 g of urea powder as the precursor was subjected to heating at 600 °C in air for 2 hours, cooling to room temperature, and then heating at 600 °C in air for 1 hour to obtain graphitic carbon nitride according to Example 4.

[0115] Example 5

[0116] 10 g of urea powder as the precursor compound was subjected to three times of sequential process of (a) heating at 600 °C in air for 1 hours and (b) cooling to room temperature to obtain graphitic carbon nitride according to Example 5.

[0117] Example 6

[0118] 10 g of urea powder as the precursor compound was subjected to heating at 600 °C in air for 2 hours, cooling to room temperature, and then two times of sequential process of (a) heating at 600 °C in air for 1 hour and (b) cooling to room temperature to obtain graphitic carbon nitride according to Example 6.

[0119] Example 7

[0120] 12 g of urea powder as the precursor compound was subjected to three times of sequential process of (a) heating at 600 °C in air for 1 hour and (b) cooling to room temperature to obtain graphitic carbon nitride according to Example 7.

[0121] Example 8

[0122] 10 g of urea powder as the precursor compound was heated at 600 to 605 °C in air for 2 hours to obtain graphitic carbon nitride according to Example 8.

[0123] Example 9

[0124] 3 g of melamine powder as the precursor compound was subjected to heating at 550 °C in air for 5 hours to obtain graphitic carbon nitride according to Example 9.

[0125] Example 10

[0126] 20 g of guanidine carbonate powder as the precursor was subjected to heating at 600 °C in air for 2 hours to obtain graphitic carbon nitride according to Example 10.

[0127] [Evaluation]

[0128] (Crystalline Structure)

[0129] The crystalline structure of each of the graphitic carbon nitride was characterized using X-ray diffraction (XRD) analysis. In the XRD pattern, the peak at 13° was assigned to (100) of graphitic carbon nitride having heptazine units; the peak at 27° was assigned to (002) plane of the c-axis in stacked sheets of graphitic carbon nitride. Figure 1 shows XRD pattern of graphitic carbon nitride according to Example 2 as a representative example.

[0130] According to the XRD analysis on the graphitic carbon nitride of each of Examples 1 to 10, they were confirmed that each of the graphitic carbon nitride according to Example 1 to 10 had the multi-layered sheets of graphitic carbon nitride with heptazine units.

[0131] (Elemental Composition Analysis)

[0132] Elemental composition of each of the graphitic carbon nitride was estimated using CNHO elemental analysis based on combustion of the samples.

[0133] (Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) Analysis) TOF-SIMS analysis was conducted to analyze whether functional groups are present in each of the graphitic carbon nitride. For the TOF-SIMS analyses, TOF.SIMS 5 (ION-TOF GmbH, Germany) was used. The irradiated primary ion was209Bi3++.

[0134] In the TOF-SIMS spectra (the analyzed area: 90,000 pm2) of Example 2, the intensity of m / z=17 attributable to OH- ion was 1460 and that of m / z=30 attributable to NO- was 92.

[0135] In the TOF-SIMS spectra (the analyzed area: 90,000 pm2) of Example 4, the intensity of m / z=17 attributable to OH- ion was 764 and that of m / z=30 attributable to NO- was 59.

[0136] In the TOF-SIMS spectra (the analyzed area: 40,000 pm2) of Example 8, the intensity of m / z=17 attributable to OH- ion was 1195 and that of m / z=30 attributable to NO- was 86.

[0137] In the TOF-SIMS spectra (the analyzed area: 40,000 pm2) of Example 9, the intensity of m / z=17 attributable to OH- ion was 1342 and that of m / z=30 attributable to NO- was 88.

[0138] In the TOF-SIMS spectra (the analyzed area: 40,000 pm2) of Example 10, the intensity of m / z=17 attributable to OH- ion was 1671 and that of m / z=30 attributable to NO- was 73.

[0139] According to the TOF-SIMS analysis on the graphitic carbon nitride of each of Examples 1 to 10, it was confirmed that each of the graphitic carbon nitride comprised nitroso groups and hydroxy groups.

[0140] (UV Absorption Property, and Yellowness Index)

[0141] The performance of light absorption of each of the graphitic carbon nitride in the wavelength range of ultraviolet light and visible light was evaluated using ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy (UV2500PC, Shimadzu Corporation) coupled with integrating sphere.

[0142] The UV-vis absorption spectra of an aqueous dispersion with 0.1% by weight of each of the graphitic carbon nitride (medium: water) in Fine quartz cell (two transparent Sides, 2 mm (optical path length) x 10 mm x H45 mm, Tokyo Garasu Kikai Co., Ltd.) was collected using UV -Visible spectrophotometer (V750, Jasco Inc.) coupled with integrating sphere.

[0143] The onset adsorption edge was estimated from UV-vis diffuse reflectance spectrum of each sample.

[0144] Figure 2 shows absorption spectra obtained via UV-vis diffuse reflectance measurement of the as-synthesized powder of graphitic carbon nitride according to Examples 1 to 7. All the graphitic carbon nitride exhibited absorption in the UV range, in which the wavelength is lower than 400 nm.

[0145] Figure 3 shows the absorption spectrum of the liquid sample suspended with 0.1 wt% of graphitic carbon nitride according to Example 9 in water, as the representative example. The aqueous suspension exhibited absorption in the wavelength range of UV, which is lower than 400 nm.

[0146] Yellowness index, which is an index of the yellow color, was also evaluated from UV-vis diffuse reflectance spectrum of each powder sample. The calculation of yellowness index and white value were conducted using the software of Shimadzu equipped to the device, where illuminant C was used as a standard illuminant and a viewing angle was set to 10°. BaSO4 standard white plate was used as a reference.

[0147] The results are summarized in Table 1 as below. Also, the relationship between concentration of oxygen atoms (at.%) in the graphitic carbon nitride and the onset absorption edge value is summarized in Figure 4(a) and the relationship between concentration of oxygen atoms (at.%) in the graphitic carbon nitride and the measured yellowness index is summarized in Figure 4(b).

[0148] Table 1

[0149] Table 1 and Figure 4(a) show that there is a tendency that the greater the amount of oxygen atoms, greater the onset absorption edge value of graphitic carbon nitride.

[0150] Also, the graph of Figure 4(b) clearly indicates that the higher concentration of oxygen atoms (at.%) in the graphitic carbon nitride produces the higher yellowness index of the graphitic carbon nitride. This indicates that the higher concentration of oxygen atoms the graphitic carbon nitride has, the more yellowish appearance the graphitic carbon nitride can exhibit.

[0151] Thus, the graphitic carbon nitride according to the present invention has very outstanding effect that it is possible to alter and design the desired color appearance as well as UV absorption property by functionalizing the graphitic carbon nitride with an oxygen-including functional group being nitroso group.

[0152] Accordingly, it can be concluded that the graphitic carbon nitride of the present invention is very useful as a UV absorber for various products, since it can provide products with a desired coloring property and attractive appearance. In particular, the graphitic carbon nitride of the present invention is very useful as a UV absorber for cosmetic products, since it can provide the keratinous substances, such as skin, with UV protection and a desired color tone which contributes to improved color management.

Claims

CLAIMS1. Use of a graphitic carbon nitride containing at least one oxygen atom, as a paint active, as a pigment, as a filler especially of plastics, or as a cosmetic active.

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

3. Use of the graphitic carbon nitride according to claim 1 or 2 as UVA and / or B absorber.

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

5. Use of the graphitic carbon nitride according to claim 4, wherein the heptazine unit is represented by formula (I), its salts and its solvates such as hydrates :in Formula (I),R1, R2, and R3, identical or different, represent: i) a hydrogen atom, ii) an halogen atom, iii)an oxygen-containing group as carboxy, nitro, or nitroso group, iv)a saturated or unsaturated, acyclic linear or branched, and / or cyclic, aromatic or nonaromatic, hydrocarbon chain containing from 1 to 10 carbon carbons, the said hydrocarbon chain being potentially interrupted by one or more heteroatom such as O, S, N or N(O); v) hydroxy, vi)amino R4R5N-, wherein R4and R5, identical or different, represent a hydrogen atom, (Ci-C6)alkyl group or another monovalent heptazine group, preferably a monovalentwherein R1and R2are as defined hereinbefore; vii) R4R5N(O)-, wherein R4and R5, identical or different, are as defined herein before; and viii)R4-N(0)- or ; wherein R4is as defined herein before; it being understood that :- at least one of radical R1, R2or R3represents v) a hydroxy group, more preferably R1 represents v) hydroxy group and R2and R3, identical or different, preferably identical, represent iii) nitroso group selected from vi) to viii), more preferably viii), and- one or more nitrogen into the cycles can be oxidized (N-oxide, or N-OH).

6. Use of the graphitic carbon nitride according to claim 5, 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-, wherein R4and R5, identical or different, represent a hydrogen atom, or another monovalent heptazine group (II) wherein R1and R2are as defined herein before; and viii) nitroso R4-N(O)- wherein R4is as defined herein before; preferably at least one of radical R1, R2or R3represents v) a hydroxy group.

7. Use of the graphitic carbon nitride according to claim 5 or 6, wherein the heptazine unit bears a succession of heptazine groups (II) via the any of groups vi) to viii), especially via the groups vi) or viii) in R1, R2, and / or R3as defined in claim 5 or 6, and preferably at least one of radical R1, R2or R3represents v) a hydroxy group.

8. Use of the graphitic carbon nitride according to any one of the preceding claims, wherein the amount of the oxygen atom in the graphitic carbon nitride ranges 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 amount of the graphitic carbon nitride.

9. Use of the graphitic carbon nitride according to any one of the preceding claims, wherein the graphitic carbon nitride has a porous structure.

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

11. Use of the graphitic carbon nitride according to any one of the preceding claims, wherein the graphitic carbon nitride has an onset absorption edge value ranging from 390 to 480 nm, preferably from 400 to 450 nm.

12. Graphitic carbon nitride containing at least one oxygen atom as defined in any one of claims 1 to 11, wherein the oxygen atom is present in at least one nitroso group (NO).

13. Graphitic carbon nitride as defined in any one of claims 1 to 12, wherein the said graphitic carbon nitride has at least one heptazine unit in the structure.

14. Graphitic carbon nitride as defined in any one of claims 1 to 13, wherein the said graphitic carbon nitride has at least one heptazine unit in the structure having at least one hydroxy group and / or at least one nitroso group, or N-oxide, preferably having at least on hydroxy group and at least one nitroso group.

15. Composition comprising the graphitic carbon nitride as defined in any one of thepreceding claims, and water and / or at least one organic media.

16. Composition, preferably cosmetic, containing at least one graphitic carbon nitride as defined in any one of the preceding claims, preferably the composition is a sunscreen composition.

17. Composition according to claim 15 or 16, which comprises TiCh 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, more preferably does comprises neither TiCh nor ZnO.

18. Process to prepare the graphitic carbon nitride as defined in any one of claims 12 to14, comprising: i) preparing at least one precursor compound; and ii) heating the at least one precursor compound at 450 °C or more for at least 1 minute; preferably in the said the heating ii) is carried out in a presence of oxygencontaining species such as O2, humidity, O3, O atomic, and / or ionic oxygen, as an oxidizing agent; preferably the oxidizing agent used during the heating step is in a gas form; more preferably the oxygen-containing species is neither from permanganate salt nor from hydrogen peroxide.

19. Process for treating keratin material, especially human keratin material such as skin, or keratin fibers such as hair, by application on the said material the composition according to any one of the claims 15 to 17.

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