JP6233219B2 - Ultraviolet shielding powder and method for producing the same - Google Patents

Description

  The present invention relates to an ultraviolet shielding powder used as a raw material for sunscreen and the like and a method for producing the same. In particular, fullerene or graphene, which is an allotrope of carbon, is used as a powder base material, and the antioxidant power of the powder base material is possessed. The present invention relates to an ultraviolet shielding powder that is difficult to decrease and a method for producing the same.

  In recent years, there are concerns about the development of skin cancer caused by the ultraviolet rays contained in the sunlight from the ozone hole due to the destruction of the ozone layer, and as a raw material for sunscreens, an ultraviolet shielding powder that effectively absorbs and scatters ultraviolet rays ( Research and development of UV-cutting powders are underway.

  By the way, in the ultraviolet rays contained in sunlight, UV-C (180 to 280 nm) is absorbed by the ozone layer so that it does not reach the earth's surface, and UV-B (280 to 320 nm) is also shielded by organic compounds. It was possible to (cut).

  However, since UV-A (320 to 400 nm) is harmful such as causing skin cancer, Patent Document 1 discloses a zinc oxide alloy powder containing at least one of lithium, sodium, and potassium as a raw material for sunscreen and the like. It is disclosed. And, it is said that a wide range of ultraviolet rays can be shielded by using a zinc oxide alloy powder containing lithium or the like, but the zinc oxide alloy powder produced by the wet method exhibited a white color due to aggregation and was applied to cosmetics. In this case, there is a defect that it is whitish and the finish is not transparent, and the manufacturing efficiency is very poor.

Patent Document 2 discloses an ultraviolet blocking agent composed of inorganic oxide fine particles such as cerium oxide CeO ₂ , titanium oxide, and zinc oxide ZnO having a band gap in the range of 2.5 to 3.2 eV. However, cerium oxide CeO ₂ has a high catalytic activity and promotes oxidative decomposition of resins, oils and fats, and therefore causes discoloration and odor when cerium oxide CeO ₂ is blended in cosmetics and resins. There was a problem. Further, an ultraviolet protective agent containing titanium dioxide TiO ₂ or zinc oxide ZnO has a high ultraviolet scattering effect and is effective in protecting the skin from ultraviolet rays. However, metal compounds such as titanium dioxide TiO ₂ and zinc oxide ZnO are known to express active oxygen on the surface when exposed to ultraviolet rays, and active oxygen is extremely reactive and can be used for a long time like cosmetics. In the case of repeated and continuous use, there is a concern about the effect on the skin tissue.

Accordingly, in order to reduce the oxidation catalytic activity of the cerium oxide CeO _{2 and} the photocatalytic activity of titanium dioxide TiO ₂ and zinc oxide ZnO, a method of coating the surface of these inorganic oxide fine particles with amorphous silica SiO ₂ is disclosed in Patent Document 3. Is disclosed.

By the way, in order to meet market demands for transparency and chromaticity for resin compositions and oil compositions containing ultraviolet cut powder (ultraviolet shielding powder), ultraviolet cut powder is further finely divided, The surface area tends to increase. An increase in the powder specific surface area results in an increase in the required coating amount, and a considerable amount of silica SiO ₂ is required to reduce the catalytic activity of the inorganic oxide fine particles. As a result, the quality of cerium oxide CeO ₂ , titanium dioxide TiO ₂ , and zinc oxide ZnO as inorganic oxide fine particles deteriorated, and there was a problem that the ultraviolet shielding effect of the ultraviolet cut powder was lowered.

  In other words, in order to meet the demands of the UV absorber market that requires finer particles, the photocatalytic activity is suppressed with a smaller amount of coating and without relatively reducing the content of UV-cutting powder (UV-blocking powder). There is an urgent need to develop surface treatment technology that can be used.

  On the other hand, in the cosmetics field, carbon materials such as charcoal powder and fullerene having an antioxidant power are partially used. Among these carbon materials, fullerene has been attracting attention in recent years in the function of antioxidant power, and a makeup cosmetic composition using fullerene as an extender or pigment is disclosed in Patent Document 4. Similarly, graphene, an allotrope of carbon, is also known to have antioxidant capacity, and the addition of plate-like graphene maintains good rheological behavior with maximum opacity A cosmetic product that can be used is disclosed in US Pat. However, it is described in Non-Patent Document 1 that fullerene generates active oxygen (singlet oxygen) when irradiated with light having a wavelength of 539 nm or less, thereby reducing the function of antioxidant power (reactive oxygen removing ability). Has been.

JP-A-6-345427 (see claim 1, paragraph 0004) JP 2002-80823 A (refer to claim 1, paragraph 0006) Japanese Patent No. 2576824 (see claim 1, paragraphs 0008-0011) Japanese Patent No. 2524476 (refer to claim 1) JP-T-2011-525557 (see paragraphs 0013-0014) JP 2007-70147 A (refer to claim 1)

Chemical Engineering, Vol.33, No.6, pp. 564-569, 2007 Journal of applied physics 97, 121301 (2005)

  The present invention has been made paying attention to such problems, and the problem is that fullerene or graphene having antioxidant power is used as a powder base material, and the antioxidant power of the powder base material is reduced. It is difficult to provide an ultraviolet shielding powder (ultraviolet cut powder) that has a high ultraviolet shielding effect in the UV-A wavelength region, has a suppressed photocatalytic activity, and can be used as a raw material for sunscreen, and a method for producing the same. .

  In order to solve the above-mentioned problems, the present inventors have conducted extensive research on the surface treatment technology in which the photocatalytic activity of the UV-cut powder is suppressed with a small amount of coating, and is actively used in the semiconductor field and the optical field. Atomic layer deposition (ALD) has been reached.

  That is, the atomic layer deposition method (ALD method) described in Non-Patent Document 2 has the following characteristics, unlike a general CVD method.

(1) Self-stop action of film formation (film formation stops at a monoatomic layer).
(2) A film can be formed even in a narrow gap (trench coating).
(3) Pinhole free.

Therefore, an inorganic oxide such as zinc oxide ZnO or cerium oxide CeO ₂ having an anti-oxidation power applied as a powder base material and having an ultraviolet shielding function in the UV-A (320 to 400 nm) wavelength region is used. The surface of the powder base material is covered by an atomic layer deposition method (ALD method), and the surface of an inorganic oxide layer such as cerium oxide CeO ₂ is covered by an atomic layer deposition method (ALD method) using silicon dioxide SiO ₂ or the like. As a result, it is possible to produce an ultraviolet shielding powder (ultraviolet cut powder) in which the antioxidant power of the powder base material such as fullerene is difficult to decrease, the ultraviolet shielding effect in the UV-A wavelength region is high, and the photocatalytic activity is suppressed. I came to find out.

Furthermore, fullerene or graphene having antioxidative power is applied as a powder substrate, and an atomic layer deposition method using an inorganic oxide such as nickel oxide NiO having an ultraviolet shielding function in a UV-B (280 to 320 nm) wavelength region ( The surface of the powder base material is covered by the ALD method) and the above-mentioned nickel oxide NiO or the like is formed by an atomic layer deposition method (ALD method) using an inorganic oxide such as zinc oxide ZnO having an ultraviolet shielding function in the UV-A wavelength region. When the surface of the inorganic oxide layer such as zinc oxide ZnO is covered by the atomic layer deposition method (ALD method) using silicon dioxide SiO ₂ etc. UV-shielding powder (ultraviolet ray) that has a high UV-shielding effect over the entire UV-A and UV-B wavelength regions and has a suppressed photocatalytic activity. Production of Ttopauda) also have found that it is possible. The present invention has been completed by such technical discovery.

That is, the first invention according to the present invention is:
In UV shielding powder,
A powder base material composed of single or aggregates of fullerene or graphene, which is an allotrope of carbon, titanium dioxide TiO ₂ (3.2 eV: a numerical value of a band gap; the same applies hereinafter), zinc oxide ZnO (3.2 eV), oxidation A coating layer selected from cerium CeO ₂ (3.1 eV) and covering the powder substrate, and a coating treatment layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ and covering the coating layer In addition, the covering layer and the covering layer are each composed of one or more atomic layers formed by an atomic layer deposition method (ALD method).

In addition, the second invention,
In UV shielding powder,
A powder base made of fullerene or graphene alone or an aggregate of carbon allotrope, nickel oxide NiO (3.6 eV), tin oxide SnO ₂ (3.6 eV) and covering the powder base A coating layer; a _second coating layer selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV) and covering the first coating layer; A coating layer that is selected from silicon SiO ₂ and aluminum oxide Al ₂ O ₃ and covers the second coating layer, and the first coating layer, the second coating layer, and the coating processing layer are atomic layer deposition methods. It is characterized by comprising at least one atomic layer formed by (ALD method).

Next, the third invention is:
In the method for producing an ultraviolet shielding powder according to the first invention,
Titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV) using the atomic layer deposition method (ALD method) on the surface of a powder base material consisting of fullerene or graphene, which are allotropes of carbon, or aggregates Depositing a coating layer selected from cerium oxide CeO ₂ (3.1 eV);
Forming a coating treatment layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O _{3 on the} surface of the coating layer using an atomic layer deposition method (ALD method);
It is characterized by comprising,
The fourth invention is:
In the method for producing an ultraviolet shielding powder according to the second invention,
Nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV) are formed on the surface of a powder base material composed of single or aggregates of fullerene or graphene, which are allotropes of carbon, using an atomic layer deposition method (ALD method). Forming a first coating layer selected from:
The surface of the first coating layer was selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV) using an atomic layer deposition method (ALD method). Forming a second coating layer;
Forming a coating treatment layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O _{3 on the} surface of the second coating layer using an atomic layer deposition method (ALD method);
It is characterized by comprising.

The ultraviolet ray shielding powder according to the first invention is selected from a powder base material composed of a simple substance or an aggregate of fullerene or graphene which is an allotrope of carbon, titanium dioxide TiO ₂ , zinc oxide ZnO, cerium oxide CeO ₂ and the above-mentioned It is composed of a coating layer covering the powder base material and a coating treatment layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ and covering the coating layer, and the coating layer and the coating treatment layer are atomic layer deposited. Each layer is composed of one or more atomic layers formed by the method (ALD method).

Then, according to the ultraviolet shielding powder according to the first invention, the titanium dioxide TiO _2, zinc oxide ZnO, the UV-A (320~400nm) wavelength region by the action of the coating layer is selected from cerium oxide CeO ₂ A coating selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O _{3 that} has a high ultraviolet shielding effect and is unlikely to cause a reduction in the antioxidant power of the powder substrate made of fullerene or graphene due to the ultraviolet shielding effect. Photocatalytic activity is also suppressed by the action of the treatment layer.

Further, the ultraviolet shielding powder according to the second invention is selected from a powder base material consisting of fullerene or graphene, which is an allotrope of carbon, or agglomerates, nickel oxide NiO, tin oxide SnO _2, and the above powder base material A second coating layer selected from titanium dioxide TiO ₂ , zinc oxide ZnO, cerium oxide CeO ₂ and covering the first coating layer, silicon dioxide SiO ₂ , aluminum oxide Al ₂ O ₃ A first layer formed by the atomic layer deposition method (ALD method), and the first coating layer, the second coating layer, and the coating processing layer, which are selected and cover the second coating layer Each of the above atomic layers is constituted.

According to the ultraviolet shielding powder according to the second invention, the action of the second coating layer selected from titanium dioxide TiO ₂ , zinc oxide ZnO, cerium oxide CeO ₂ , and nickel oxide NiO or tin oxide SnO By the action of the first coating layer selected from _{2, the} ultraviolet shielding effect over the entire UV-A (320 to 400 nm) wavelength range and UV-B (280 to 320 nm) wavelength range is high, and the ultraviolet shielding effect described above The effect of the coating treatment layer selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ is less likely to reduce the antioxidant power of powder base materials made of fullerene or graphene. have.

Furthermore, the coating layer of the ultraviolet shielding powder, the first coating layer and the second coating layer, and the coating treatment layer are each composed of a thin film by an atomic layer deposition method (ALD method). _{2. It} also has the effect of saving expensive film materials such as zinc oxide ZnO, cerium oxide CeO ₂ , nickel oxide NiO, tin oxide SnO ₂ .

Sectional drawing of the ultraviolet-shielding powder (ultraviolet cut powder) which concerns on a comparative example. Sectional drawing of the ultraviolet-shielding powder (ultraviolet cut powder) which concerns on a comparative example. Sectional drawing of the ultraviolet-shielding powder (ultraviolet cut powder) concerning this invention. Sectional drawing of the ultraviolet-shielding powder (ultraviolet cut powder) concerning this invention. Sectional drawing of the ultraviolet-shielding powder (ultraviolet cut powder) concerning this invention. Sectional drawing of the ultraviolet-shielding powder (ultraviolet cut powder) concerning this invention. Explanatory drawing which shows the apparatus of an atomic layer deposition method. Explanatory drawing which shows the apparatus of an atomic layer deposition method.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the contents described in the following embodiments.

That is, the ultraviolet shielding powder (ultraviolet cut powder) according to the first embodiment is
A powder base made of fullerene or graphene, which is an allotrope of carbon, or agglomerates, and selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV). And a coating layer covering the powder base material, and a coating treatment layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ and covering the coating layer, and the coating layer and the coating treatment layer Each layer is composed of one or more atomic layers deposited by atomic layer deposition (ALD),
The ultraviolet shielding powder (ultraviolet cut powder) according to the second embodiment is
A powder base made of fullerene or graphene alone or an aggregate of carbon allotrope, nickel oxide NiO (3.6 eV), tin oxide SnO ₂ (3.6 eV) and covering the powder base A coating layer; a _second coating layer selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV) and covering the first coating layer; A coating layer that is selected from silicon SiO ₂ and aluminum oxide Al ₂ O ₃ and covers the second coating layer, and the first coating layer, the second coating layer, and the coating processing layer are atomic layer deposition methods. It is characterized by comprising at least one atomic layer formed by (ALD method).

1. Powder base material The powder base material of the ultraviolet shielding powder (ultraviolet cut powder) according to the present invention is composed of a fullerene or graphene, which is an allotrope of carbon, or an aggregate.

  The fullerene is a carbon material in which 20 or more carbon atoms are bonded in a “cage shape” to form hollow particles having a closed shell structure. The most typical fullerenes are fullerene C60 in which 60 carbon atoms form particles similar to a soccer ball, fullerene C70 consisting of 70 carbon atoms, fullerene C76 consisting of 76 carbon atoms, Examples include fullerene C78 composed of 78 carbon atoms, and fullerene C84 composed of 84 carbon atoms. Any of these may be used, and a mixture thereof may be used.

  A fullerene raw material powder is pulverized by applying mechanical force to the fullerene raw material powder, and the fullerene raw material powder is pulverized so that the average particle size is 10 μm or less, preferably 1 μm or less. The pulverization method is performed by, for example, the friction between the pulverizer and the fullerene powder described in Patent Document 6, or the pulverization method (grinding method) using the friction between the fullerene powders. It is preferable to carry out by a pulverization method (composite method) combining a method and other mechanical forces such as a compression force, a shear force, and an impact force.

  Fullerene has an antioxidant power, but generates active oxygen (singlet oxygen) when irradiated with light having a wavelength of 539 nm or less as described above.

Therefore, whether the powder substrate made of fullerene is covered with a coating layer selected from titanium dioxide TiO ₂ , zinc oxide ZnO, and cerium oxide CeO ₂ having an ultraviolet shielding effect in the UV-A (320 to 400 nm) wavelength region. Alternatively, the first coating layer is covered with a first coating layer selected from nickel oxide NiO and tin oxide SnO ₂ having an ultraviolet shielding effect in the UV-B (280 to 320 nm) wavelength region, and the first coating layer is coated with the titanium dioxide TiO ₂ and the oxide. By covering with a second coating layer selected from zinc ZnO and cerium oxide CeO _2, it is possible to suppress the generation of active oxygen, so that the ultraviolet shielding effect is maintained without impairing the properties of the antioxidant power possessed by the powder base material. Can be granted.

Graphene, an allotrope of carbon, has a hexagonal lattice structure like a “honeycomb” made of carbon atoms and their bonds. In addition, the crystal has a scaly shape. Preferably, graphene having a diameter of 2 μm or less and a specific surface area of 300 to 750 m ² / g can be used as a powder base material.

  Graphene is preferably used as a powder base material for applications that require good covering ability and moderate opacity.

2. Atomic Layer Deposition (ALD) method is a method in which source gases containing elements constituting a molecular layer (atomic layer) are alternately introduced into a vacuum apparatus and placed in a vacuum apparatus. This is a method in which a single atom (monomolecular) layer is deposited by the reaction between the molecules adsorbed on the outermost surface of the film and the source gas introduced next, and the layer thickness can be controlled at the atomic layer level. is there.

  The atomic layer deposition method is a method in which film formation starts while depositing single atom (monomolecular) layers one by one from the film formation target side, so that a coating layer without pinholes on the film formation target (powder substrate). (First coating layer, second coating layer) and the like can be formed. This atomic layer deposition method is a general vacuum film formation method (vacuum deposition method, sputtering method, ion plating method, ion beam sputtering method, etc.), in which film material clusters fly onto the film formation target, Since the above-mentioned cluster is bonded to the surface of the film body and is bonded to form a film, it is greatly different from a general vacuum film forming method which has a possibility of creating pinholes between the clusters. In addition, it is possible to form a uniform film on the surface of an object to be deposited, which is difficult to form by sputtering or vacuum vapor deposition, which is highly straight, and by atomic layer deposition. Since the raw material is a gas, there is no occurrence of splash (the film raw material flying to the film formation body in a solid state) frequently generated by sputtering or vacuum deposition. Accordingly, there is no phenomenon in which the splash adheres to the film being formed and falls off to form a pinhole. In addition, the vacuum apparatus used in the atomic layer deposition method does not require an expensive power supply unit or the like necessary for the vacuum apparatus used in the PVD method or the CVD method, and the film formation is performed in comparison with the conventional film formation method. Cost can also be reduced.

  In the atomic layer deposition method, the first reaction gas (reaction gas 1) and the second reaction gas (reaction gas 2) containing each of the elements constituting the molecular layer are alternately placed in a vacuum device (reaction chamber). The following steps A to I to be introduced constitute one cycle, and the film thickness is adjusted by the number of cycles.

A. B. Introduction of the first reactive gas (reactive gas 1) into the vacuum apparatus. C. First reaction gas is chemisorbed on the outermost surface of the deposition target. D. Saturation of the outermost surface of the deposition target with the first reaction gas Evacuate excess first reactant gas and by-products from the vacuum apparatus E. F. introduction of the second reactive gas (reactive gas 2) into the vacuum device. G. First reaction gas and second reaction gas adsorbed on the outermost surface of the deposition target react. The outermost surface of the deposition target is saturated with the second reaction gas. Exhaust excess second reaction gas and by-products from the vacuum system

In the atomic layer deposition method, oxide films such as silicon dioxide SiO ₂ , Al ₂ O ₃ , ZrO ₂ , HfO ₂ , Ta ₂ O ₅ , titanium dioxide TiO ₂ , AlN, TaN, TiN, TaSiN, TiSiN, etc. Nitride films, metal films such as Cu, Ru, Ir, Ni, and Pt, fluoride films such as CaF ₂ , SrF ₂ , and MgF ₂ , and compound films such as GaAs, InP, and GaP can be formed.

For example, when forming a monoatomic (monomolecular) layer of aluminum oxide Al ₂ O ₃ which is most frequently formed by atomic layer deposition, one cycle takes four steps (i) to (iv) below. Complete.

(I) Introducing water molecules as the first reaction gas to adsorb OH groups on the outermost surface of the film formation target.
(Reaction after the first layer)
2H ₂ O +: O—Al (CH ₃ ) ₂ →: Al—O—Al (OH) ₂ + 2CH ₄
(Ii) Purge and exhaust excess water molecules.
(Iii) TMA [Trimethyl Aluminum: Al (CH ₃ ) ₃ ] gas, which is the second reaction gas (reaction gas 2) of the aluminum oxide Al ₂ O ₃ film, is introduced. TMA molecules react with OH groups to generate CH ₄ gas.
(First layer reaction)
Al (CH ₃ ) ₃ +: O—H →: O—Al (CH ₃ ) ₂ + CH ₄
(Reaction after the first layer)
Al (CH ₃ ) ₃ +: Al—O—H →: Al—O—Al (CH ₃ ) ₂ + CH ₄
(Iv) Purge and exhaust excess TMA gas and CH ₄ gas.

Since an aluminum oxide Al ₂ O ₃ film having a thickness of about 0.1 nm is formed in these four steps, the above four steps are repeated until the required film thickness is reached, and the film thickness is increased.

  In the atomic layer deposition method, it is preferable to heat the film formation body (100 to 300 ° C.) or perform plasma in order to promote the reaction.

  Basically, other film types can also be formed by a four-step process of introducing a first reactive gas, purging, introducing a second reactive gas, and purging, except that the reactive gas is different. Furthermore, since the film formation by the atomic layer deposition method has a refining action in which impurities are hardly taken in, a high-purity film can be obtained even when a low-purity reaction gas is used.

3. Equipment for atomic layer deposition The equipment for atomic layer deposition has a relatively simple structure as a vacuum film-forming device and is commercially available from many equipment manufacturers. Is a device attached.

  A typical atomic layer deposition apparatus suitable for film formation on powder is shown in FIGS.

  The atomic layer deposition method apparatus shown in FIG. 7 is an apparatus for forming a film on the surface of a thinly spread powder 102. Inside the vacuum chamber 100 is a powder tray 101 containing powder 102. The powder tray 101 may be vibrated so that the powder 102 moves. A vacuum pump (dry pump) 104 is connected to the vacuum chamber 100 via a main valve 103. Further, a valve 107 and a flow meter 108 for introducing a plurality of reaction gases are attached. Some valves 107 are accompanied by a mechanism for heating the gas. In order to promote film formation, it is preferable to have a heater 105 and a plasma source 106.

  In addition, the atomic layer deposition method does not require as high vacuum as the vacuum evaporation method or sputtering method, so it does not require an oil diffusion pump, turbo molecular pump, cryopump, etc. to obtain a high vacuum, and is used as a roughing pump Rotary pumps, dry pumps, and the like that are used can be used.

  Further, the gas supply valve 107 of the atomic layer deposition method can prevent liquefaction by incorporating a heater when the reaction gas is liquefied.

  Next, the atomic layer deposition apparatus shown in FIG. 8 is an apparatus for forming a film on each surface of the powder 202 spread in multiple stages in the powder can 201. Inside the vacuum chamber 200 is the powder can 201 that spreads the powder 202 in multiple stages. The powder can 201 may be vibrated so that the powder 202 can move. A vacuum pump (dry pump) 204 is connected to the vacuum chamber 200 via a main valve 203. Further, a valve 207 for introducing a plurality of reaction gases and a flow meter 208 are attached. Some valves 207 are accompanied by a mechanism for heating the gas. In order to promote film formation, it is preferable to include a heater 205 and a plasma source 206. Reference numeral 209 denotes a filter.

4). Film material for atomic layer deposition Between the light wavelength λ (nm) and the photon energy hν (eV),
hν = hc / λ = 1239.8 / λ (Formula 1)
It is known that this relationship holds.

For example, since the band gap of titanium dioxide TiO ₂ is 3.2 eV, light shorter than the wavelength of 387 nm at the optical absorption edge is absorbed, and all longer wavelengths are transmitted.

It is preferable to use a coating material that can absorb and scatter light in the UV-A (320 to 400 nm) wavelength range that is harmful to the skin. When the UV-A (320 to 400 nm) wavelength region is represented by a band gap, it is about 3.1 to 3.9 eV, and titanium dioxide TiO ₂ (3.2 eV) as a metal oxide that can cover the UV-A wavelength region widely, Zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV) are used.

  When a film material having a band gap of less than 3.1 eV is used, the absorption of light reaches the visible light region, so that coloring becomes strong, and blending into cosmetics, films, plastics, paints, and the like is restricted.

Film materials of titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV) are effective for UV-A (320 to 400 nm) wavelength ultraviolet rays. However, the blocking effect is not sufficient for ultraviolet rays in the UV-B (280 to 320 nm) region. For this reason, nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3. 3) exhibiting an effective ultraviolet blocking effect against ultraviolet rays in the UV-B (280 to 320 nm) region as the second layer coating material. It is preferable to use one or more selected from 6eV). Thereby, it is possible to substantially block the transmission of ultraviolet rays over almost the entire UV-B to UV-A region, and in particular, it is possible to easily obtain an ultraviolet blocking agent that efficiently blocks ultraviolet rays in the UV-A region.

Silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ is used as a coating material for suppressing the oxidation catalyst activity of cerium oxide CeO _{2 and} the photocatalytic activity of titanium dioxide TiO ₂ and zinc oxide ZnO.

  Reactive gases that form films by atomic layer deposition are sold by various companies. Table 1 below shows typical reaction gases of the coating employed in the present invention.

  These typical coating materials (reactive gases) described in Non-Patent Document 2 are summarized in Table 1, but are not limited to the coating materials (reactive gases) shown here.

（注）
「Ｍｅ」： Methyl
「Ｅｔ」： Ethyl
「ＯＭｅ」： Methoxy
「ＯＥｔ」： Ethoxy
「ａｃａｃ」： Acetylaceto-nato
「ｔｈｄ」： 2, 2, 6, 6-Tetramethyl-3, 5-heptanedionate
「ａｐｏ」： 2-Amino-Pent-2-en-4-onate
「ｄｍｇ」： Dimethyl-glyoximato

(note)
"Me": Methyl
“Et”: Ethyl
“OMe”: Methoxy
“OEt”: Ethoxy
“Acac”: Acetylaceto-nato
“Thd”: 2, 2, 6, 6-Tetramethyl-3, 5-heptanedionate
“Apo”: 2-Amino-Pent-2-en-4-onate
“Dmg”: Dimethyl-glyoximato

5. Structure of ultraviolet shielding powder (ultraviolet cut powder) The ultraviolet shielding powder (ultraviolet cut powder) according to the present invention is applied to a powder base material composed of a single substance or an aggregate of carbon fullerene or graphene. Metal oxides titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV), which absorb light in the UV-A (320-400 nm) wavelength region, and , A metal oxide nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV) that absorb light in the UV-B (280 to 320 nm) wavelength region are formed by atomic layer deposition. Is.

(1) Ultraviolet shielding powder according to the first embodiment to which “fullerene” is applied As shown in FIG. 3, “fullerene” is used for the powder base material 50, and UV is applied to the coating layer 51 covering the powder base material 50. Forming a material selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV) having a high ultraviolet shielding effect in the -A wavelength region; and The ultraviolet shielding powder according to the first embodiment is formed by depositing a material selected from silica SiO ₂ and aluminum oxide Al ₂ O ₃ on the coating layer 52 covering the coating layer 51.

When the coating layer 52 is formed by forming a material selected from silica SiO ₂ and aluminum oxide Al ₂ O _3, the coating layer is an extremely thin film composed of at least one atomic layer (molecular layer). By covering 51, the UV-A of the coating layer 51 made of a material selected from titanium oxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV) A decrease in the ultraviolet shielding effect in the wavelength region can be suppressed.

(2) Ultraviolet shielding powder according to the first embodiment to which “graphene” is applied As shown in FIG. 4, “graphene” is used for the powder base 60 and UV is applied to the coating layer 61 covering the powder base 60. Forming a material selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV) having a high ultraviolet shielding effect in the -A wavelength region; and The ultraviolet shielding powder according to the first embodiment is formed by depositing a material selected from silica SiO ₂ and aluminum oxide Al ₂ O ₃ on the coating layer 62 covering the coating layer 61.

(3) Ultraviolet shielding powder according to the second embodiment to which “fullerene” is applied As shown in FIG. 5, the first coating layer 71 that covers the powder base material 70 using “fullerene” as the powder base material 70. In addition, a film selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV) exhibiting an effective ultraviolet blocking effect even for ultraviolet rays in the UV-B wavelength region is formed. A titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV) having a high ultraviolet shielding effect in the UV-A wavelength region is applied to the second coating layer 72 covering the one coating layer 71. In the second embodiment, a material selected from silica SiO ₂ and aluminum oxide Al ₂ O ₃ is formed on the coating layer 73 covering the second coating layer 72. UV shielding powder according to the form is composed That.

(4) Ultraviolet shielding powder according to the second embodiment to which “graphene” is applied As shown in FIG. 6, the first coating layer 81 that uses “graphene” as the powder base material 80 and covers the powder base material 80 In addition, a film selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV) exhibiting an effective ultraviolet blocking effect even for ultraviolet rays in the UV-B wavelength region is formed. A titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV) having a high UV shielding effect in the UV-A wavelength region is applied to the second coating layer 82 covering the one coating layer 81. In the second embodiment, a material selected from silica SiO ₂ and aluminum oxide Al ₂ O ₃ is formed on the coating layer 83 covering the second coating layer 82. UV shielding powder according to the form is composed That.

(5) The structure of the ultraviolet shielding powder (ultraviolet cut powder) according to the present invention is UV-B applied to the first coating layers 71 and 81 covering the powder base materials 70 and 80 as shown in FIGS. A film selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV) exhibiting an effective ultraviolet blocking effect against ultraviolet rays in the wavelength region, and the first coating layers 71 and 81 are covered. The second coating layers 72 and 82 are selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV) which have a high UV shielding effect in the UV-A wavelength region. And a three-layer structure including a coating selected from silica SiO ₂ and aluminum oxide Al ₂ O _{3 in the} coating layers 73 and 83 covering the second coating layers 72 and 82.

That is, a film selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV) having a high ultraviolet shielding effect in the UV-A wavelength region is applied to the outer layer (first layer). Nickel oxide NiO (3.6 eV) or tin oxide SnO ₂ (3.6 eV), which is a second coating layer 72, 82, which is a two-layer), and exhibits an effective ultraviolet blocking effect even for ultraviolet rays in the UV-B wavelength region. The first coating layers 71 and 81 which are inner layers (first layers) are preferably used.

In contrast to the structure shown in FIGS. 5 and 6, titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3) having a high UV shielding effect in the UV-A wavelength region is used for the inner layer (first layer). .2 eV), nickel oxide which is composed of a film selected from cerium oxide CeO ₂ (3.1 eV), and has an outer layer (second layer) that effectively blocks ultraviolet rays in the UV-B wavelength region. When the coating is selected from NiO (3.6 eV) or tin oxide SnO ₂ (3.6 eV), nickel oxide NiO (3.6 eV) or tin oxide SnO ₂ (3 .6 eV) is not preferable because the ultraviolet shielding effect in the UV-A wavelength region is lowered due to the influence of the film.

(6) Further, as shown in FIGS. 3 and 4, when the outermost layer of the ultraviolet shielding powder (ultraviolet cut powder) is composed of cerium oxide CeO ₂ having oxidation catalytic activity, cerium oxide CeO having oxidation catalytic activity The action of ₂ promotes the oxidative decomposition of resins and oils and fats, causing discoloration and odor when blended in cosmetics and resins. In addition, when the outermost layer is composed of titanium dioxide TiO ₂ and zinc oxide ZnO having photocatalytic activity, active oxygen is expressed by absorption of light, so there is a concern about the effect on skin tissue when used as a cosmetic. For this reason, in order to suppress these catalytic activities, it is necessary to coat silica SiO ₂ or aluminum oxide Al ₂ O ₃ as a coating treatment layer.

6). Film Forming Method Using the atomic layer deposition apparatus shown in FIG. 7, a coating layer is formed on the outer surface of the powder 102 made of “fullerene” or “graphene”, which is a powder base thinly spread in the powder tray 101. A method will be described.

  First, a powder 102 made of “fullerene” or “graphene”, which is a powder base material, is inserted into a powder tray 101 inside the vacuum chamber 100.

  Next, after evacuating the vacuum chamber 100 to 5 Pa with the large dry pump 104, the powder 102 is preferably heated to 300 ° C. with a heater. That is, in order to promote film formation, it is preferable to heat the powder 102 to about 300 ° C. using the heater 105. By heating to about 300 ° C., the adsorbed water and gas of the powder 102 can be removed, and then good film formation can be performed. Further, the characteristics of the ultraviolet cut powder can be stabilized by the annealing effect.

  Moreover, it is preferable to give vibration to the powder tray 101 so that the powder 102 can move. However, when the amount of the powder 102 is small, the film can be formed without applying vibration.

  Thereafter, in order to form the first layer (first coating layer), the four-step process of the above atomic layer deposition method is repeated 20 times using two kinds of reaction gases, and then the second layer (second coating layer) is formed. In order to form a film, the four-step process of the atomic layer deposition method is repeated 20 times with two kinds of reactive gases, and then the four-step process of the atomic layer deposition method is repeated 20 times in order to form a coating treatment layer. After completing the film formation repeatedly, the vacuum chamber 100 is opened to the atmosphere, and the ultraviolet shielding powder (ultraviolet cut powder) according to the second embodiment of the present invention can be obtained.

  The film thickness of each layer is determined by the number of four-step processes (number of atomic layers). Here, the four-step process is repeated 20 times, but is not limited to 20 times.

  Then, the relationship between the “number of times of the four-step process and the film thickness” when the following material is formed is as follows.

That is, an aluminum oxide Al ₂ O ₃ film (about 0.1 nm / time), a silicon dioxide SiO ₂ film (about 0.06 nm / time), a titanium dioxide TiO ₂ film (about 0.05 nm / time), a zinc oxide ZnO film (About 0.2 nm / time), cerium oxide CeO ₂ film (about 0.25 nm / time), nickel oxide NiO film (about 0.025 nm / time), and tin oxide SnO ₂ (about 0.2 nm / time) It is.

  From these data, the film thicknesses of the coating layer, the first coating layer, the second coating layer, and the coating treatment layer are determined by determining the number of four-step processes by the atomic layer deposition method (ALD method). It can be accurately controlled and may be composed of one or more, preferably 1 to 40 atomic layers (molecular layers).

  Examples of the present invention will be specifically described below with reference to comparative examples, but the present invention is not limited to these examples.

[Example 1]
Using the atomic layer deposition apparatus shown in FIG. 7, a coating layer and a coating treatment layer are sequentially formed on the outer surface of the powder 102 made of “fullerene” which is a powder base material. A powder (ultraviolet cut powder) was produced.

  That is, after the powder 102 made of “fullerene” was inserted into the powder tray 101 inside the vacuum chamber 100, the vacuum chamber 100 was evacuated to 5 Pa by the large dry pump 104.

  Next, the powder 102 is heated to 300 ° C. using the heater 105 during film formation preparation and film formation, and the powder is passed through the powder tray 101 so that uniform film formation can be performed during film formation. 102 was vibrated.

That is, while applying vibration to the powder 102, the four-step process of the above atomic layer deposition method was repeated 20 times using two types of reactive gases to form titanium dioxide TiO ₂ as the first layer (coating layer). In addition, in order to form silica SiO ₂ as a coating treatment layer, the four-step process of the atomic layer deposition method using two kinds of reactive gases is repeated 20 times to complete the film formation, and then the vacuum chamber 100 is opened to the atmosphere. An ultraviolet shielding powder (ultraviolet cut powder) according to Example 1 was produced.

[Characteristic measurement of UV cut powder]
Next, the obtained ultraviolet shielding powder (ultraviolet cut powder) has a “screening (cut) effect in the UV-A wavelength region” (abbreviated as “UV-A cut effect” in the table), and “catalytic activity The “suppression effect” (abbreviated as “catalytic activity suppression effect” in the table) was measured.

(1) Shielding (cut) effect in the UV-A wavelength region First, after the obtained ultraviolet shielding powder (ultraviolet cut powder) is dispersed in ethanol, light in the UV-A wavelength region (320 to 400 nm) is transmitted. On the synthetic quartz glass, the dispersion was applied and dried so that the thickness after drying was about 10 μm.

  The dried ultraviolet shielding powder (ultraviolet cut powder) was measured for diffuse transmission characteristics in the UV-A wavelength range with a self-recording spectrophotometer to evaluate the "shielding (cut) effect in the UV-A wavelength range". .

  That is, when the transmittance at a wavelength of 350 nm was 50% or more, the evaluation was “X”, when it was 10% or less and less than 50%, “◯”, and when it was less than 10%, “◎”.

  The results are listed in Table 2 below.

(2) Effect of inhibiting catalytic activity Next, the effect of inhibiting the catalytic activity of the obtained ultraviolet shielding powder (ultraviolet cut powder) was examined.

  As a measure of the suppression effect, a certain amount of ultraviolet shielding powder (ultraviolet cut powder) is put together with acetaldehyde gas into a transparent sealed container and irradiated with ultraviolet light. The degradation rate due to oxidation was measured and evaluated.

  That is, when the decomposition rate of acetaldehyde by auto-oxidation was 50% or more, the evaluation was “X”, when it was 10% or less and less than 50%, “◯”, and when it was less than 10%, “◎”.

  The results are also listed in Table 2 below.

[Examples 2 to 12 and Comparative Examples 1 to 8]
“Fullerene” or “graphene” shown in Table 2 is applied as a powder base material, and “titanium dioxide”, “zinc oxide”, “cerium oxide”, “nickel oxide” and “tin oxide” shown in Table 2 are used as a coating layer. Examples 2 to 12 and Comparative Examples were applied in the same manner as in Example 1 except that either of these was applied and “silicon dioxide (silica SiO ₂ )” or “aluminum oxide” shown in Table 2 was applied as the coating treatment layer. The ultraviolet shielding powder (ultraviolet cut powder) according to 1 to 8 was produced.

  Table 2 shows the “screening (cutting) effect in the UV-A wavelength region” and the “catalytic activity-suppressing effect” of each obtained UV screening powder (ultraviolet cut powder).

[Example 13]
Using the atomic layer deposition method apparatus shown in FIG. 7, the “first coating layer”, “second coating layer”, and “coating treatment layer” are sequentially formed on the outer surface of the powder 102 made of “fullerene” as the powder base material. Film formation was performed to produce an ultraviolet shielding powder (ultraviolet cut powder) according to Example 13.

  The “second coating layer” and the “coating treatment layer” are formed under the same conditions as in Example 1, and the “first coating layer” has two types of reactions to form nickel oxide NiO. The four-step process of the atomic layer deposition method described above is repeated 20 times.

  Table 3 shows the “shielding effect in the UV-A wavelength region” and the “catalytic activity suppression effect” in the obtained ultraviolet shielding powder (ultraviolet cut powder).

[Examples 14 to 36 and Comparative Examples 9 to 20]
“Fullerene” or “graphene” shown in Table 3 is applied as the powder base material, and “nickel oxide”, “tin oxide”, “titanium dioxide”, “zinc oxide” and “cerium oxide” shown in Table 3 are used as the first coating layer. Any one of these is applied, and any one of “titanium dioxide”, “zinc oxide”, “cerium oxide” and “nickel oxide” shown in Table 3 is applied as the second coating layer, and the coating treatment layer is shown in Table 3 Ultraviolet shielding powders (ultraviolet cut powders) according to Examples 14 to 36 and Comparative Examples 9 to 20 were produced in the same manner as in Example 13 except that “silicon dioxide” or “aluminum oxide” was applied.

  Table 3 shows the “screening (cutting) effect in the UV-A wavelength region” and the “catalytic activity suppressing effect” of each obtained UV screening powder (ultraviolet cut powder).

[Comparative Examples 21-38]
“Fullerene” or “graphene” shown in Table 4 is applied as the powder base material, and “titanium dioxide”, “zinc oxide”, “cerium oxide”, “nickel oxide” and “tin oxide” shown in Table 4 are used as the first coating layer. Example 1 except that any one of them is applied and any one of “titanium dioxide”, “zinc oxide” and “cerium oxide” shown in Table 4 is applied as the second coating layer, and no coating treatment layer is provided. In the same manner as in Example 13, ultraviolet shielding powders (ultraviolet cut powders) according to Comparative Examples 21 to 38 were produced.

  1 is a cross-sectional view of ultraviolet shielding powder (ultraviolet cut powder) according to Comparative Examples 21 to 23 to which “fullerene” is applied, and FIG. 2 is an ultraviolet ray according to Comparative Examples 24 to 26 to which “graphene” is applied. The cross-sectional view of the shielding powder (ultraviolet cut powder) is shown.

  Table 4 shows the “screening (cutting) effect in the UV-A wavelength region” and the “catalytic activity suppressing effect” of each obtained UV screening powder (ultraviolet cut powder).

"Evaluation"
(1) From the results shown in Table 2, titanium dioxide TiO ₂ , zinc oxide ZnO, and cerium oxide CeO ₂ having a high ultraviolet shielding effect in the UV-A (320 to 400 nm) wavelength region are used for the first layer (coating layer). In the ultraviolet shielding powder (ultraviolet cut powder) according to Examples 1 to 12, in which an inorganic oxide selected from 1 is formed and a coating treatment layer selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ is provided. Are all evaluated as “◯” for “shielding (cut) effect in the UV-A wavelength region” (transmittance at a wavelength of 350 nm of 10% or less and less than 50%), and all of “catalytic activity suppression effect” The evaluation is “◎” (the decomposition rate of acetaldehyde by auto-oxidation is less than 10%), and it is confirmed that the properties as an ultraviolet cut powder are good.

(2) On the other hand, an inorganic oxide selected from nickel oxide NiO and tin oxide SnO ₂ having an ultraviolet shielding effect in the UV-B (280 to 320 nm) wavelength region is formed on the first layer (coating layer), In the ultraviolet shielding powder (ultraviolet cut powder) according to Comparative Examples 1 to 8 provided with a coating treatment layer selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ , “shielding (cutting in UV-A wavelength region (cut)” ) "Effect" is all evaluated as "x" (transmittance at a wavelength of 350 nm is 50% or more), and it is confirmed that the properties as an ultraviolet cut powder are not good.

(3) From the results shown in Table 3, the first layer (first coating layer) is selected from nickel oxide NiO and tin oxide SnO ₂ having an ultraviolet shielding effect in the UV-B (280 to 320 nm) wavelength region. An inorganic oxide film is formed, and titanium dioxide TiO ₂ , zinc oxide ZnO, and cerium oxide CeO having a high ultraviolet shielding effect in the UV-A (320 to 400 nm) wavelength region are formed on the second layer (second coating layer). forming a selected inorganic oxide from _2, and ultraviolet shielding powder (UV according to example 13 to 36 in which a coating treatment layer selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ In “powder”, the “screening (cut) effect in the UV-A wavelength range” is all evaluated as “◎” (the transmittance at a wavelength of 350 nm is less than 10%), and the “catalytic activity suppression effect” is all ◎ has become rated as (less than the decomposition rate of 10%) ", it is confirmed properties as UV powder is very good.

(4) On the other hand, the first layer (first coating layer) is an inorganic material selected from titanium dioxide TiO ₂ , zinc oxide ZnO, and cerium oxide CeO ₂ having a high ultraviolet shielding effect in the UV-A (320 to 400 nm) wavelength region. An oxide is formed, and an inorganic oxide selected from nickel oxide NiO or tin oxide SnO ₂ having an ultraviolet shielding effect in the UV-B (280 to 320 nm) wavelength region is formed on the second layer (second coating layer). In the ultraviolet shielding powders (ultraviolet cut powders) according to Comparative Examples 9 to 20 which were formed and provided with a coating treatment layer selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ , In the ultraviolet shielding powder (ultraviolet cut powder) according to Comparative Examples 9 to 20 in which the constituent materials of the layer (first coating layer) and the second layer (second coating layer) are reversed from those of Examples 13 to 36, “ V-A shield in the wavelength range (cut) effect "all evaluation" × "(transmittance at a wavelength of 350nm is 50% or more) has become, it is confirmed that the characteristics of the UV powder not good.

(5) Further, from the results shown in Table 4, titanium dioxide TiO ₂ , zinc oxide ZnO having a high ultraviolet shielding effect in the UV-A (320 to 400 nm) wavelength region, zinc oxide ZnO, and Ultraviolet shielding powders (ultraviolet rays) according to Comparative Examples 21 to 26 in which an inorganic oxide selected from cerium oxide CeO ₂ is formed, but the second layer (second coating layer) and the coating treatment layer are not provided. In “cut powder”, the “shielding effect in the UV-A wavelength region” is all evaluated as “◯” (the transmittance at a wavelength of 350 nm is 10% or less and less than 50%). "" Is evaluated as "x" (decomposition rate by autooxidation of acetaldehyde is 50% or more), and it is confirmed that the properties as an ultraviolet cut powder are not good.

(6) From the results shown in Table 4, the first layer (first coating layer) is selected from nickel oxide NiO and tin oxide SnO ₂ having an ultraviolet shielding effect in the UV-B (280 to 320 nm) wavelength region. An inorganic oxide film is formed, and titanium dioxide TiO ₂ , zinc oxide ZnO, and cerium oxide CeO having a high ultraviolet shielding effect in the UV-A (320 to 400 nm) wavelength region are formed on the second layer (second coating layer). _{In the} ultraviolet shielding powder (ultraviolet cut powder) according to Comparative Examples 27 to 38 in which an inorganic oxide selected from ₂ is formed, but no coating treatment layer is provided, “in the UV-A wavelength region” The “shielding (cut) effect” is all evaluated as “◎” (transmittance at a wavelength of 350 nm is less than 10%), but the “catalytic activity suppression effect” is all “×” (decomposition rate by acetaldehyde autooxidation is 50). Characteristics of the UV powder has become a rating above) is confirmed to be not good.

(7) From the results described above, a powder base composed of “fullerene” or “graphene”, titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV) And a coating layer that covers the powder substrate and a coating layer that is selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ and covers the coating layer. The ultraviolet shielding powder (ultraviolet cut powder) according to Examples 1 to 12, each of which is composed of one or more atomic layers formed by the layer deposition method, has a “shielding effect in the UV-A wavelength region”. It is understood that it is suitable as a raw material for sunscreen, etc.

(8) Similarly, a powder base made of “fullerene” or “graphene”, and a first coating selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV) and covering the powder base A second coating layer selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV) and covering the first coating layer, silicon dioxide SiO ₂ and a coating treatment layer selected from aluminum oxide Al ₂ O ₃ and covering the second coating layer, and the first coating layer, the second coating layer and the coating treatment layer are formed by an atomic layer deposition method. Further, the ultraviolet shielding powders (ultraviolet cut powders) according to Examples 13 to 36 each composed of one or more atomic layers are also “shielding effect in the UV-A wavelength region” and “suppression of catalytic activity”. Because of excellent effect ", it is understood that suitable as a raw material, such as sunscreen.

  Since the ultraviolet shielding powder (ultraviolet cut powder) according to the present invention is excellent in the shielding effect in the UV-A (320 to 400 nm) wavelength region and the catalytic activity suppressing effect, it is industrially applied to raw materials such as sunscreens. Have the availability of.

30 Powder base material (fullerene)
31 1st layer (1st coating layer)
40 Powder base (graphene)
41 1st layer (1st coating layer)
50 Powder base material (fullerene)
51 1st layer (coating layer)
52 Coating treatment layer 60 Powder base material (graphene)
61 First layer (coating layer)
62 Coating layer 70 Powder base material (fullerene)
71 1st layer (1st coating layer)
72 Second layer (second coating layer)
73 Coating layer 80 Powder base (graphene)
81 1st layer (1st coating layer)
82 Second layer (second coating layer)
83 Coating layer 100 Vacuum chamber 101 Powder tray 102 Powder 103 Main valve 104 Vacuum pump 105 Heating heater 106 Plasma source 107 Valve 108 Flow meter 200 Vacuum chamber 201 Powder can 202 Powder 203 Main valve 204 Vacuum pump 205 Heating heater 206 Heating heater 207 Valve 208 Flow meter 209 Filter

Claims (4)

A powder base material composed of single or aggregates of fullerene or graphene, which is an allotrope of carbon, titanium dioxide TiO ₂ (3.2 eV: a numerical value of a band gap; the same applies hereinafter), zinc oxide ZnO (3.2 eV), oxidation A coating layer selected from cerium CeO ₂ (3.1 eV) and covering the powder substrate, and a coating treatment layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ and covering the coating layer In addition, an ultraviolet shielding powder, wherein the coating layer and the coating layer are each composed of one or more atomic layers formed by an atomic layer deposition (ALD) method. A powder base made of fullerene or graphene alone or an aggregate of carbon allotrope, nickel oxide NiO (3.6 eV), tin oxide SnO ₂ (3.6 eV) and covering the powder base A coating layer; a _second coating layer selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV) and covering the first coating layer; A coating layer that is selected from silicon SiO ₂ and aluminum oxide Al ₂ O ₃ and covers the second coating layer, and the first coating layer, the second coating layer, and the coating processing layer are atomic layer deposition methods. An ultraviolet shielding powder comprising at least one atomic layer formed by (ALD method). In the manufacturing method of the ultraviolet-shielding powder of Claim 1,
Titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV) using the atomic layer deposition method (ALD method) on the surface of a powder base material consisting of fullerene or graphene, which are allotropes of carbon, or aggregates Depositing a coating layer selected from cerium oxide CeO ₂ (3.1 eV);
Forming a coating treatment layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O _{3 on the} surface of the coating layer using an atomic layer deposition method (ALD method);
The manufacturing method of the ultraviolet-shielding powder characterized by comprising. In the manufacturing method of the ultraviolet-shielding powder of Claim 2,
Nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV) are formed on the surface of a powder base material composed of single or aggregates of fullerene or graphene, which are allotropes of carbon, using an atomic layer deposition method (ALD method). Forming a first coating layer selected from:
The surface of the first coating layer was selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV) using an atomic layer deposition method (ALD method). Forming a second coating layer;
Forming a coating treatment layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O _{3 on the} surface of the second coating layer using an atomic layer deposition method (ALD method);
The manufacturing method of the ultraviolet-shielding powder characterized by comprising.

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