JP2016020418A - Ultraviolet ray shielding powder and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet ray shielding powder (ultraviolet ray cut powder) which has high ultraviolet shielding effect in a UV-A (320 to 400 nm) wavelength range and can be used for a raw material of sunscreen or the like due to inhibition of a catalytic activity and a manufacturing method therefor.SOLUTION: An ultraviolet ray shielding powder is constituted of a fine particle substrate 50 consisting of fine particles having average particle diameter of 10 to 500 nm selected from nickel oxide and tin oxide having an ultraviolet ray shielding effect in a UV-B (280 to 320 nm) wavelength range, a coating layer 51 selected from titanium dioxide, zinc oxide ZnO, and cerium oxide having the ultraviolet ray shielding effect in the UV-A wavelength range and coating the fine particle substrate 50 and a coating treatment layer 52 selected from silicon dioxide and aluminum oxide and coating the coating layer. The coating layer and the coating treatment layer are constituted of one or more atom layers deposited by an atomic layer deposition method (ALD method).SELECTED DRAWING: Figure 2

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, and in particular, an improvement of an ultraviolet shielding powder having a high ultraviolet shielding effect in the UV-A wavelength region and a reduced catalytic activity. It relates to the manufacturing method.

  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 catalyst 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.

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)

Journal of applied physics 97, 121301 (2005)

  The present invention has been made paying attention to such problems, and the problem is that the ultraviolet ray shielding effect is high in the UV-A (320 to 400 nm) wavelength region, and the catalytic activity is suppressed, so An object of the present invention is to provide an ultraviolet shielding powder (ultraviolet cut powder) that can be used as a raw material for stoppers and the like and a method for producing the same.

  In order to solve the above problems, the present inventor has conducted extensive research on the surface treatment technology that suppresses the catalytic activity of the UV-cut powder 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 1 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 and cerium oxide CeO ₂ having an ultraviolet shielding function in a UV-A (320 to 400 nm) wavelength region is applied as a fine particle substrate, and atoms are formed using silicon dioxide SiO ₂ or the like. layer deposition was covered particulate substrate surface, such as cerium oxide CeO ₂ by (ALD method), high ultraviolet shielding effects in UV-a wavelength range, ultraviolet shielding powder catalyst activity was suppressed (UV powder) It has been found that it is possible to manufacture.

Further, an inorganic oxide such as nickel oxide NiO having an ultraviolet shielding function in the UV-B (280 to 320 nm) wavelength region is applied as a fine particle substrate, and zinc oxide ZnO having an ultraviolet shielding function in the UV-A wavelength region In addition, the surface of the fine particle substrate such as nickel oxide NiO is covered by an atomic layer deposition method (ALD method) using an inorganic oxide such as cerium oxide CeO ₂ , and the atomic layer deposition method (ALD method) using silicon dioxide SiO ₂ or the like. ) To cover the surface of an inorganic oxide layer such as zinc oxide ZnO, an ultraviolet shielding powder (ultraviolet ray) having a high ultraviolet shielding effect over the entire UV-A wavelength region and UV-B wavelength region and suppressing catalytic activity. It has been found that it is possible to manufacture cut powder). 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,
Fine particles having an average particle diameter of 10 to 500 nm selected from titanium dioxide TiO ₂ (3.2 eV: numerical value of band gap; the same applies hereinafter), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV). And a coating treatment layer that is selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ and covers the fine particles, and the coating treatment layer is formed by an atomic layer deposition method (ALD method). It is characterized by comprising one or more atomic layers.

In addition, the second invention,
In UV shielding powder,
Fine particles having an average particle diameter of 10 to 500 nm selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV), titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV) A coating layer selected from cerium oxide CeO ₂ (3.1 eV) and covering the fine particles, and a coating treatment layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ and covering the coating layer, 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).

Next, the third invention is:
In the method for producing an ultraviolet shielding powder according to the first invention,
Atomic layer deposition method (ALD method) on the surface of fine particles having an average particle size of 10 to 500 nm selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV) ) To form a coating layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ ,
The fourth invention is:
In the method for producing an ultraviolet shielding powder according to the second invention,
On the surface of fine particles having an average particle diameter of 10 to 500 nm selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV), titanium dioxide TiO ₂ (3. 2 eV), zinc oxide ZnO (3.2 eV), 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 ultraviolet shielding powder according to the first invention is a fine particle having an average particle size of 10 to 500 nm selected from titanium dioxide TiO ₂ , zinc oxide ZnO, and cerium oxide CeO ₂ , silicon dioxide SiO ₂ , and aluminum oxide Al ₂ O _3. And a coating treatment layer that covers the fine particles, and the coating treatment layer is composed of one or more atomic layers formed by an atomic layer deposition method (ALD method). .

Then, according to the ultraviolet shielding powder according to the first invention, the titanium dioxide TiO _2, zinc oxide ZnO, by the action of the fine particles selected from cerium oxide CeO _2, in UV-A (320~400nm) wavelength region The ultraviolet ray shielding effect is high, and the catalytic activity is also suppressed by the action of the coating treatment layer selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ .

The ultraviolet shielding powder according to the second invention is composed of fine particles having an average particle diameter of 10 to 500 nm selected from nickel oxide NiO and tin oxide SnO ₂ , titanium dioxide TiO ₂ , zinc oxide ZnO, and cerium oxide CeO _2. A coating layer that is selected and covers the fine particles, and a coating treatment layer that is selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ and covers 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).

According to the ultraviolet shielding powder according to the second invention, the action of the fine particles selected from nickel oxide NiO and tin oxide SnO _2, and selected from titanium dioxide TiO ₂ , zinc oxide ZnO and cerium oxide CeO _2. Due to the action of the coated layer thus formed, the UV-A (320 to 400 nm) wavelength region and the UV-B (280 to 320 nm) wavelength region have a high ultraviolet shielding effect, and silicon dioxide SiO ₂ or aluminum oxide Al _The catalytic activity is also suppressed by the action of the coating treatment layer selected from ₂ O ₃ .

Further, since the coating layer and the coating layer of these ultraviolet shielding powders are each composed of a thin film by an atomic layer deposition method (ALD method), the above-described silicon dioxide SiO ₂ , aluminum oxide Al ₂ O ₃ , dioxide dioxide It also has an effect of saving coating raw materials such as titanium TiO ₂ , zinc oxide ZnO, cerium oxide CeO ₂ , and tin oxide SnO ₂ .

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
Fine particles having an average particle diameter of 10 to 500 nm selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV), silicon dioxide SiO ₂ , aluminum oxide Al _A coating treatment layer selected from ₂ O ₃ and covering the fine particles, and the coating treatment layer is composed of one or more atomic layers formed by an atomic layer deposition method (ALD method). As a feature,
The ultraviolet shielding powder (ultraviolet cut powder) according to the second embodiment is
Fine particles having an average particle diameter of 10 to 500 nm selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV), titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV) A coating layer selected from cerium oxide CeO ₂ (3.1 eV) and covering the fine particles, and a coating treatment layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ and covering the coating layer, 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).

1. Fine Particle Base Material The fine particle base material of the ultraviolet shielding powder (ultraviolet cut powder) according to the first embodiment is titanium dioxide TiO ₂ (3.2 eV: shows the numerical value of the band gap; the same applies hereinafter), zinc oxide ZnO (3 .2 eV), cerium oxide CeO ₂ (3.1 eV) and selected from fine particles having an average particle diameter of 10 to 500 nm, and the fine particle group of the ultraviolet shielding powder (ultraviolet cut powder) according to the second embodiment The material is composed of fine particles having an average particle diameter of 10 to 500 nm selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV). When the particle size of the fine particle substrate is about ½ of the wavelength, it becomes a Mie scattering region and has an opaque feeling, and when the particle size of the fine particle substrate is much smaller than ½ of the wavelength, the Rayleigh scattering region. Becomes transparent. The particle size of the fine particle base material may be appropriately selected according to the use of the ultraviolet shielding powder (ultraviolet cut powder) according to the present invention. It is preferably 100 nm or less that can be shielded (cut).

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 the coating layer without pinholes on the film formation target (fine particle substrate) 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 apparatus shown in FIG. 3 is an apparatus for forming a film on the surface of powder 102 spread thinly. 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. 4 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 material that can absorb and scatter light in the UV-A (320 to 400 nm) wavelength range, which is harmful to the skin, for the fine particle substrate. 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. Use of a material having a band gap of less than 3.1 eV is not preferable because the absorption of light reaches the visible light region, so that coloring becomes strong and the compounding into cosmetics, films, plastics, paints, and the like is restricted. .

However, the material selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV) is UV-A (320 to 400 nm) in the ultraviolet region. On the other hand, although an effective ultraviolet blocking effect is exhibited, the blocking effect is not sufficient for ultraviolet rays in the UV-B (280 to 320 nm) region. Therefore, at least one selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV) exhibiting an effective ultraviolet blocking effect even in the UV-B (280 to 320 nm) region. Titanium dioxide TiO ₂ (3.2 eV), zinc oxide having an ultraviolet shielding function in the UV-A (320 to 400 nm) wavelength region as a coating material that is applied to the fine particle substrate and covers the surface of the fine particle substrate A configuration using ZnO (3.2 eV) or cerium oxide CeO ₂ (3.1 eV) is preferable. 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 catalytic activity of cerium oxide CeO _{2 and} the photocatalytic activity of titanium dioxide TiO ₂ and zinc oxide ZnO.

  By the way, reaction gases for forming a film by an atomic layer deposition method are sold by various companies. Table 1 below shows typical reaction gases of the coating employed in the present invention.

  These representative coating materials (reactive gases) described in Non-Patent Document 1 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) (1) Ultraviolet shielding powder (ultraviolet cut powder) according to the first embodiment
As shown in FIG. 1, the “fine particle substrate” 30 has titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), a high ultraviolet shielding effect in the UV-A (320 to 400 nm) wavelength region, An inorganic oxide fine particle selected from cerium oxide CeO ₂ (3.1 eV) is applied, and the “coating layer” 31 covering the “fine particle substrate” 30 is selected from silica SiO ₂ and aluminum oxide Al ₂ O _3. The coated film material is applied to constitute the ultraviolet shielding powder (ultraviolet cut powder) according to the first embodiment.

When forming the “coating layer” 31 by forming a film material selected from silica SiO ₂ and aluminum oxide Al ₂ O ₃ by an atomic layer deposition method (ALD method), at least one atomic layer ( “Molecule layer” is an extremely thin film composed of inorganic oxide fine particles selected from titanium oxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV). By covering the “substrate” 30, it is possible to suppress a decrease in the ultraviolet shielding effect in the UV-A wavelength region of the “fine particle substrate” 30.

(2) Ultraviolet shielding powder (ultraviolet cut powder) according to the second embodiment
As shown in FIG. 2, nickel oxide NiO (3.6 eV), tin oxide, which has an effective ultraviolet blocking effect against ultraviolet rays in the UV-B (280 to 320 nm) wavelength region, is added to the “fine particle substrate” 50. One or more selected from SnO ₂ (3.6 eV) is applied, and the “coating layer” 51 covering the “fine particle substrate” 50 has a high ultraviolet shielding effect in the UV-A (320 to 400 nm) wavelength region. A coating material selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), cerium oxide CeO ₂ (3.1 eV) is applied, and “coating” covering the “coating layer” 51 the treated layer "52, silica SiO _2, is coating material selected from aluminum oxide Al ₂ O ₃ is applied, ultraviolet shielding powder according to the second embodiment (UV powder) is consists .

In the case where the “coating layer” 52 is formed by forming a film material selected from silica SiO ₂ and aluminum oxide Al ₂ O ₃ by an atomic layer deposition method (ALD method), at least one atomic layer ( “Coating layer” made of a coating material selected from titanium oxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV). By covering 51, it is possible to suppress a decrease in the ultraviolet shielding effect of the “coating layer” 51 in the UV-A wavelength region.

(3) The structure of the ultraviolet shielding powder (ultraviolet cut powder) according to the present invention is effective for ultraviolet rays in the UV-B wavelength region, as shown in FIG. “Coating layer” covering fine particle substrate 50 by applying fine particles having an average particle diameter of 10 to 500 nm selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV) exhibiting an ultraviolet blocking effect 51, a coating material 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. In addition, a structure in which a coating material selected from silica SiO ₂ and aluminum oxide Al ₂ O ₃ is applied to the “coating layer” 52 covering the “coating layer” 51 is most preferable.

That is, the “fine particle substrate” 50 is selected from nickel oxide NiO (3.6 eV) or tin oxide SnO ₂ (3.6 eV) which exhibits an effective ultraviolet blocking effect even for ultraviolet rays in the UV-B wavelength region. Ultraviolet-absorbing fine particles having an average particle diameter of 10 to 500 nm are applied, and the “fine particle substrate” 50 is made of titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3. 2eV) and a “coating layer” 51 selected from cerium oxide CeO ₂ (3.1 eV) is preferable.

Contrary to the structure shown in FIG. 2, “fine particle substrate” 50 includes titanium dioxide TiO ₂ (3.2 eV) and zinc oxide ZnO (3.2 eV) having a high ultraviolet shielding effect in the UV-A wavelength region. In addition, ultraviolet absorbing fine particles having an average particle size of 10 to 500 nm selected from cerium oxide CeO ₂ (3.1 eV) are applied, and the above “fine particle substrate” 50 is effective also for ultraviolet rays in the UV-B wavelength region. When coated with a “coating layer” 51 selected from nickel oxide NiO (3.6 eV) or tin oxide SnO ₂ (3.6 eV) exhibiting an ultraviolet blocking effect, nickel oxide NiO (3 .6 eV) or tin oxide SnO ₂ (3.6 eV), the ultraviolet shielding effect in the UV-A wavelength region is reduced, which is not preferable.

(4) In addition, if the outermost layer of the ultraviolet shielding powder (UV powder) is constituted by a cerium oxide CeO ₂ having an oxidation catalytic activity, oxidation of the resin and oil by the action of the cerium oxide CeO ₂ having an oxidation catalytic activity Decomposition is promoted, 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. Therefore, 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 layer” 52 as shown in FIG.

6). Film Forming Method A method for forming a coating layer on the outer surface of the powder 102, which is a fine particle substrate thinly spread in the powder tray 101, using the atomic layer deposition method shown in FIG.

  First, a powder 102 made of “ultraviolet absorbing fine particles” as a fine particle 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 (coating layer), the four-step process of the atomic layer deposition method described above is repeated 20 times using two kinds of reaction gases, and then the second layer (coating layer) is formed. Therefore, after completing the film formation by repeating the four-step process of the atomic layer deposition method using two kinds of reactive gases, the vacuum chamber 100 is opened to the atmosphere, and the ultraviolet shielding powder according to the second embodiment of the present invention (Ultraviolet cut powder) 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 method apparatus shown in FIG. 3, a coating layer is formed on the outer surface of the powder 102 made of “titanium dioxide TiO ₂ ” which is a fine particle substrate, and the ultraviolet shielding powder according to the first embodiment. (UV cut powder) was manufactured.

That is, after the powder 102 made of “titanium dioxide TiO ₂ ” 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, in order to form a silica SiO ₂ film as a coating treatment layer while applying vibration to the powder 102, after completing the film formation by repeating the four-step process of the atomic layer deposition method 20 times for two types of reaction gases, The vacuum chamber 100 was opened to the atmosphere to produce an ultraviolet shielding powder (ultraviolet cut powder) according to Example 1.

[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 into a transparent sealed container together with acetaldehyde gas 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 6 and Comparative Examples 1 to 4]
One of “titanium dioxide”, “zinc oxide”, “cerium oxide”, “nickel oxide” and “tin oxide” shown in Table 2 is applied as the fine particle substrate, and “silicon dioxide (silica SiO 2)” shown in Table 2 is used as the coating treatment layer. ₂ ) ”or“ aluminum oxide ”was used, and the ultraviolet shielding powder (ultraviolet cut powder) according to Examples 2 to 6 and Comparative Examples 1 to 4 was produced in the same manner as in Example 1.

  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 7]
Using the atomic layer deposition method shown in FIG. 3, a “coating layer” (titanium dioxide) and a “coating treatment layer” (silicon dioxide) are sequentially formed on the outer surface of the powder 102 made of “nickel oxide” which is a fine particle substrate. Then, an ultraviolet shielding powder (ultraviolet cut powder) according to Example 7 was produced.

Note that the “coating layer” (silicon dioxide) was formed under the same conditions as in Example 1, and the “coating layer” was formed of titanium dioxide TiO ₂ , so that the above-described atomic layer was used for two types of reaction gases. The four-step process of the deposition method 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 8 to 18 and Comparative Examples 5 to 10]
Any one of “nickel oxide”, “tin oxide”, “titanium dioxide”, “zinc oxide” and “cerium oxide” shown in Table 3 is applied as the fine particle base material, and “titanium dioxide” “zinc oxide” shown in Table 3 as the coating layer This was carried out in the same manner as in Example 7 except that either “cerium oxide” or “nickel oxide” was applied, and “silicon dioxide” or “aluminum oxide” shown in Table 3 was applied as the coating layer. Ultraviolet shielding powder (ultraviolet cut powder) according to Examples 8 to 18 and Comparative Examples 5 to 10 was produced.

  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 11 to 19]
Any of “titanium dioxide”, “zinc oxide”, “cerium oxide”, “nickel oxide” and “tin oxide” shown in Table 4 as the fine particle base material is applied, and “titanium dioxide” “ The ultraviolet shielding powders (ultraviolet rays) according to Comparative Examples 11 to 19 were applied in the same manner as in Example 1 or Example 7 except that any one of “zinc oxide” and “cerium oxide” was applied and no coating treatment layer was provided. Cut powder) was produced.

  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, the fine particle substrate was 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. Ultraviolet shielding powders (ultraviolet cut powders) according to Examples 1 to 6 in which inorganic oxide fine particles are used, and the surface of the fine particle substrate is covered with a coating treatment layer selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ ), The “screening (cut) 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%), and the “catalytic activity suppressing effect” Are all evaluated as “◎” (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, inorganic fine particles 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 are used as the fine particle substrate, and the surface of the fine particle substrate In the ultraviolet shielding powder (ultraviolet cut powder) according to Comparative Examples 1 to 4 covered with a coating treatment layer selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ , “shielding in the 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) Further, from the results shown in Table 3, inorganic fine particles 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 are applied to the fine particle substrate. The coating layer of the inorganic oxide 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 is used for the surface of the fine particle substrate. In the ultraviolet shielding powders (ultraviolet cut powders) according to Examples 7 to 18 in which a coating treatment layer selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ is provided, the “UV-A wavelength region” All of the “shielding (cut) effect” in the evaluation is “◎” (transmittance at a wavelength of 350 nm is less than 10%), and the “catalytic activity suppression effect” is also all “◎”. Evaluation has a (the decomposition rate is less than 10%), it is confirmed properties as UV powder is very good.

(4) On the other hand, an inorganic oxide fine particle selected from titanium dioxide TiO ₂ , zinc oxide ZnO and cerium oxide CeO ₂ having a high UV shielding effect in the UV-A (320 to 400 nm) wavelength region is used as the fine particle substrate. The fine particle substrate surface is covered with a coating layer of an inorganic oxide selected from nickel oxide NiO or tin oxide SnO ₂ having an ultraviolet shielding effect in a UV-B (280 to 320 nm) wavelength region, and silicon dioxide SiO ₂ or In the ultraviolet shielding powder (ultraviolet cut powder) according to Comparative Examples 5 to 10 provided with the coating treatment layer selected from aluminum oxide Al ₂ O ₃ , that is, the constituent material of the fine particle base material and the coating layer is Example 7. In the ultraviolet shielding powder (ultraviolet cut powder) according to Comparative Examples 5 to 10 inverted to ˜18, “shielding in the UV-A wavelength region (capacity G) effect "all evaluation" × "(which transmittance at a wavelength of 350nm becomes 50% or more), it is confirmed that the characteristics of the UV powder not good.

(5) Next, from the results shown in Table 4, from the 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, the fine particle base material is used. In the ultraviolet shielding powders (ultraviolet cut powders) according to Comparative Examples 11 to 13 in which the selected inorganic oxide fine particles were applied but the coating layer and the coating treatment layer were not provided, “shielding in the UV-A wavelength region” “Cut effect” is an evaluation of “◯” (transmittance at a wavelength of 350 nm is 10% or less and less than 50%), but “catalytic activity suppression effect” is all “×” (decomposition rate by autaldehyde autooxidation) It is confirmed that the properties as an ultraviolet cut powder are not good.

(6) Further, from the results shown in Table 4, inorganic fine particles 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 are formed on the fine particle substrate. An inorganic oxide selected from titanium dioxide TiO ₂ , zinc oxide ZnO, and cerium oxide CeO ₂ that is applied and has a fine particle base surface with a high UV shielding effect in the UV-A (320 to 400 nm) wavelength region In the ultraviolet shielding powders (ultraviolet cut powders) according to Comparative Examples 14 to 19 that have a structure covered with a coating layer, but are not provided with a coating treatment layer, “shielding (cut) in the UV-A wavelength region” “Effective” is all evaluated as “「 ”(transmittance at a wavelength of 350 nm is less than 10%), but“ inhibition effect of catalytic activity ”is all“ × ”(for acetaldehyde autooxidation) That the decomposition rate is confirmed that the characteristic as UV powder has become a rating of 50% or more) not good.

(7) From the results described above, the inorganic base material selected from titanium dioxide TiO ₂ , zinc oxide ZnO, and cerium oxide CeO ₂ having a high UV shielding effect in the UV-A (320 to 400 nm) wavelength region. The fine particle substrate surface was covered with a coating treatment layer selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ and the coating treatment layer was formed by an atomic layer deposition method. The ultraviolet shielding powders (ultraviolet cut powders) according to Examples 1 to 6 each composed of an atomic layer equal to or greater than the number of layers are the “shielding effect in the UV-A wavelength region” and the “catalytic activity suppressing effect”. It is understood that it is suitable as a raw material for sunscreen and the like.

(8) Similarly, an inorganic oxide fine particle 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 used as the fine particle substrate. The surface is covered with an inorganic oxide coating layer 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, and the coating One or more atomic layers in which the surface of the layer is covered with a coating treatment layer selected from silicon dioxide SiO ₂ or aluminum oxide Al ₂ O ₃ and the coating layer and the coating treatment layer are formed by an atomic layer deposition method UV shielding powders (ultraviolet cut powders) according to Examples 7 to 18 which are respectively constituted by the “shielding (cut) effect in the UV-A wavelength region” and the “catalytic activity suppressing effect” Excellent for use in ", it is understood that suitable as a raw material for 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 Fine particle substrate (UV absorbing fine particle)
31 Coating layer 50 Fine particle substrate (ultraviolet absorbing fine particles)
51 Coating layer 52 Coating treatment 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 Heater 207 Valve 208 Flow meter 209 Filter

Claims (4)

Fine particles having an average particle diameter of 10 to 500 nm selected from titanium dioxide TiO ₂ (3.2 eV: numerical value of band gap; the same applies hereinafter), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV). And a coating treatment layer that is selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ and covers the fine particles, and the coating treatment layer is formed by an atomic layer deposition method (ALD method). An ultraviolet shielding particle comprising one or more atomic layers. Fine particles having an average particle diameter of 10 to 500 nm selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV), titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV) A coating layer selected from cerium oxide CeO ₂ (3.1 eV) and covering the fine particles, and a coating treatment layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ and covering the coating layer, An ultraviolet shielding particle, wherein the coating layer and the coating treatment layer are each composed of one or more atomic layers formed by an atomic layer deposition method (ALD method). In the manufacturing method of the ultraviolet-shielding powder of Claim 1,
Atomic layer deposition method (ALD method) on the surface of fine particles having an average particle size of 10 to 500 nm selected from titanium dioxide TiO ₂ (3.2 eV), zinc oxide ZnO (3.2 eV), and cerium oxide CeO ₂ (3.1 eV) ) Is used to form a coating layer selected from silicon dioxide SiO ₂ and aluminum oxide Al ₂ O ₃ . In the manufacturing method of the ultraviolet-shielding powder of Claim 2,
On the surface of fine particles having an average particle diameter of 10 to 500 nm selected from nickel oxide NiO (3.6 eV) and tin oxide SnO ₂ (3.6 eV), titanium dioxide TiO ₂ (3. 2 eV), zinc oxide ZnO (3.2 eV), 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);
A method for producing ultraviolet shielding particles, comprising:

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