JP2017043505A - Manufacturing method of uv light shielding material particulates, uv light shielding material particulate dispersoid using uv light shielding material particulates, and uv light shielding body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of manufacturing UV light shielding material particulates having sufficiently suppressed optical catalytic activity and high UV light shielding property while having a simple catalytic activity suppression effect-imparting step, a UV light shielding material particulate dispersoid that uses the UV light shielding material particulates, and a UV light shielding body.SOLUTION: A manufacturing method of UV light shielding material particulates is provided, the method includes a step of depositing precipitates of a zinc oxide precursor by dropping an aqueous solution in which one kind or more of compounds containing a predetermined additive element is dissolved into an aqueous solution containing a predetermined zinc oxide precursor, a decantation step of cleansing the deposited precipitates, a step of forming a wet-processed product by wet-treating the precipitates after the cleansing with an alcoholic solution, and, after that, of obtaining a zinc oxide precursor treated powder containing the predetermined compound by drying the wet-treated product, and a step of obtaining UV-light shielding material particulates containing zinc oxide particulates in which, by heating the zinc oxide precursor treated powder under a predetermined atmosphere and under a predetermined temperature, a zinc element in a zinc oxide crystal is substituted with a predetermined element and is dissolved therein.SELECTED DRAWING: None

Description

  The present invention is a photocatalyst applied to a transparent base material that requires an ultraviolet shielding function used for a cover of a window such as a vehicle, a building, an office, a general house, a telephone box, a show window, a lighting lamp, or a transparent case. The present invention relates to a method for producing fine particles of ultraviolet shielding material with suppressed activity, and further relates to an ultraviolet shielding material fine particle dispersion using the ultraviolet shielding material fine particles and an ultraviolet shielding material.

  The zinc oxide fine particles transmit visible light, and the ultraviolet cut wavelength region is wider to the longer wavelength side than the titanium oxide fine particles. Further, in the zinc oxide fine particles, the ultraviolet ray cutting effect lasts for a long time. Because of these features, zinc oxide fine particles are used as one of ultraviolet shielding materials. For example, the fine particles are contained in a resin and used as a resin molded product such as a film, fiber, and resin plate, or the fine particles and an organic or inorganic binder are mixed to form a film, fiber, resin plate, glass, and paper. It is used as a paint to paint on a substrate such as.

  However, when the zinc oxide fine particles are exposed on the paint surface, the zinc oxide fine particles are transformed into zinc hydroxide due to moisture in the air, and the paint surface becomes cloudy. As a result, films, resin molded products and paints using zinc oxide fine particles are inferior in durability.

  Moreover, since zinc oxide has reactivity depending on the resin to be used in combination, it has problems such as limiting the range of resins that can be used in combination. Furthermore, since the zinc oxide fine particles have photocatalytic activity, there is a problem that when irradiated with ultraviolet rays, the organic oxide is decomposed and deteriorated near the surface of the zinc oxide fine particles. In response to the problem that the zinc oxide fine particles have reactivity and photocatalytic activity, as a method for suppressing the reactivity and photocatalytic activity, a method of coating the surface of the zinc oxide fine particles with a predetermined compound is known.

  For example, Patent Document 1 discloses that a cyclic silicone compound or a low-molecular-weight linear silicone compound is brought into contact with a powder having active sites on the surface in the form of vapor, and the silicone compound is deposited on the entire surface of the powder. A method has been proposed in which a modified powder carrying a silicone polymer coating on the entire surface of the powder is obtained by polymerization, and further modified to achieve the modification of the powder having active sites. .

Patent Document 2 discloses that one or more of Al, Si, Zr, Sn oxides or hydroxides are formed on the surface of zinc oxide fine particles having an average particle diameter of 0.1 μm or less with respect to zinc oxide. A method of coating 0.1 to 20% by weight is disclosed.
The oxides or hydroxides of Si and Zr are mainly deactivated by reducing the catalytic activity of the zinc oxide fine particles by coating the zinc oxide fine particles, while the oxidation of Al, Zr and Sn. The product or hydroxide is one that covers the zinc oxide fine particles to reduce its dynamic friction coefficient, and the dynamic friction coefficient of the oxide or hydroxide is small. Here, the zinc oxide fine particles are hexagonal, Although the particle shape has a prismatic shape, it has been proposed that the corners become rounded by being covered with the oxide or hydroxide so as to be nearly spherical as a whole.

In Patent Document 3, zinc oxide fine particles are prepared by using a zinc oxide precursor such as Zn ₅ (OH) ₆ (CO ₃ ) ₂ , ZnCO ₃ , Zn ₄ CO ₃ (OH) ₆ H ₂ O by a wet method. A method of manufacturing is disclosed. Specifically, the zinc oxide precursor is immersed in an alcohol solution containing one or more elements selected from Si, Al, Zr, and Ti in an amount of more than 0% by weight and 15% by weight or less in terms of oxide. After the treatment, it is dried to obtain a zinc oxide precursor containing one or more elements selected from Si, Al, Zr, and Ti, and after heat treatment, any one or more of Si, Al, Zr, and Ti A method for producing zinc oxide fine particles in which the photocatalytic activity is suppressed by coating the zinc oxide fine particles with an oxide containing these elements is disclosed.

  Patent Document 4 proposes a method of surface-treating the surface of the zinc oxide fine powder with an aluminum chelate compound or a cyclic aluminum oligomer for the purpose of suppressing the photocatalytic activity of the zinc oxide fine powder and imparting dispersibility. ing.

  In Patent Document 5, the photocatalytic activity of zinc oxide fine particles per se is suppressed, and the dispersibility in resin compositions (paints, coating films, films, resin molded products, fibers, etc.) and oil and fat compositions (cosmetics, etc.) is disclosed. In order to improve the above, a method of coating the surface of zinc oxide particles with 0.2 to 10% by weight of a silane coupling agent with respect to zinc oxide has been proposed.

However, when the present inventor examined the prior art from the viewpoints of ultraviolet shielding performance, transparency, and manufacturing cost, it was found that there were the following problems.
That is, all the prior arts according to Patent Documents 1 to 5 use means for applying a coating treatment to the surface of the zinc oxide fine particles. However, the means for coating the surface of the zinc oxide fine particles requires a drying or baking process after the coating process, resulting in poor productivity. Further, it is not satisfactory from the viewpoint of ultraviolet shielding properties and photocatalytic activity suppression, and there is room for improvement.

Japanese Unexamined Patent Publication No. 63-139015 Japanese Patent Laid-Open No. 03-183620 JP 2009-132599 A Japanese Patent No. 3491983 Japanese Patent No. 3485634

  The present invention has been made in the above-mentioned situation, and the problem is that the photocatalytic activity suppressing effect imparting step is simple, but the photocatalytic activity is sufficiently suppressed and the ultraviolet shielding material fine particles having high ultraviolet shielding properties are obtained. The manufacturing method which manufactures, the ultraviolet-ray shielding material fine particle dispersion using the said ultraviolet-ray shielding material microparticles | fine-particles, and an ultraviolet shielding body are provided.

The present inventors have conducted intensive research to solve the above-described problems.
Then, the ultraviolet shielding material fine particles including zinc oxide fine particles in which the zinc element in the zinc oxide crystal is substituted and dissolved with one or more elements selected from Si, Al, Zr and Ti are dispersed in the medium. By using the ultrafine UV shielding material particle dispersion, transparency and photocatalytic activity are suppressed compared to the conventional UV shielding material that has been coated on the surface of zinc oxide particles to suppress photocatalytic activity and ensure UV shielding properties. It has been found that an ultraviolet shielding material fine particle dispersion and an ultraviolet shielding body excellent in effect and ultraviolet shielding properties can be obtained.

Furthermore, the inventors of the present invention have disclosed ultraviolet ray shielding material fine particles including zinc oxide fine particles in which zinc element in a zinc oxide crystal is substituted and dissolved by one or more elements selected from Si, Al, Zr and Ti. As a manufacturing method,
An aqueous solution in which one or more compounds including one or more additive elements selected from Si, Al, Zr, and Ti are dissolved in an aqueous solution of a predetermined zinc oxide precursor is dropped, and the zinc oxide precursor and the A step of depositing a mixed precipitate with the compound of the additive element;
After decantation until the conductivity of the liquid after washing the mixed precipitate becomes a predetermined value or less, the mixed precipitate after the decantation is wet-treated with an alcohol solution to obtain a wet-treated product, Drying the wet processed product to obtain a zinc oxide precursor-treated powder containing one or more compounds selected from Si, Al, Zr and Ti;
Zinc oxide fine particles obtained by heat-treating the zinc oxide precursor-treated powder under predetermined conditions and replacing the zinc element in the zinc oxide crystal with one or more elements selected from Si, Al, Zr and Ti. The present invention has been completed by conceiving a method for producing fine particles of ultraviolet shielding material comprising the step of obtaining fine particles of ultraviolet shielding material comprising:

That is, the first invention for solving the above-described problem is
To an aqueous solution containing one or more zinc oxide precursors selected from Zn ₅ (OH) ₆ (CO ₃ ) ₂ , ZnCO ₃ , Zn ₄ CO ₃ (OH) ₆ H ₂ O, Zn (OH) ₂ , Si An aqueous solution in which one or more compounds containing one or more additive elements selected from Al, Zr, and Ti are dissolved is dropped, and the compound of the additive element is 15% by mass or more and 35% by mass or less in terms of oxide Depositing a precipitate of the zinc oxide precursor comprising:
A decantation step of washing the deposited precipitate and continuing washing until the conductivity of the solution after washing becomes 1 mS / cm or less;
The washed precipitate is wet-treated with an alcohol solution to obtain a wet-processed product, and then the wet-processed product is dried to contain a zinc oxide precursor containing one or more compounds selected from Si, Al, Zr and Ti. Obtaining body treatment powder;
The zinc oxide precursor-treated powder is heat-treated at a temperature of 300 ° C. or higher and 650 ° C. or lower in any atmosphere selected from the atmosphere, an inert gas, and a mixed gas of an inert gas and a reducing gas. In addition, zinc oxide fine particles in which zinc element in the zinc oxide crystal is substituted and dissolved by one or more elements selected from Si, Al, Zr and Ti, and the average particle diameter is 8.3 nm or more and 15.4 nm or less And a step of obtaining ultraviolet shielding material fine particles containing zinc oxide fine particles having a specific surface area of 67 m ² / g or more and 124 m ² / g or less.
The second invention is
Zinc oxide fine particles in which zinc element in the zinc oxide crystal is substituted and dissolved by one or more elements selected from Si, Al, Zr and Ti,
Ultraviolet shielding material fine particles including the zinc oxide fine particles having an average particle diameter of 8.3 nm to 15.4 nm and a specific surface area of 67 m ² / g to 124 m ² / g are dispersed in a medium. It is an ultraviolet shielding material fine particle dispersion characterized.
The third invention is
The ultraviolet shielding material fine particle dispersion according to the second invention, wherein the medium is resin or glass.
The fourth invention is:
The ultraviolet ray shielding material fine particle dispersion according to any one of the second and third inventions is processed into any shape selected from a plate shape, a film shape, and a thin film shape. It is a shield.
The fifth invention is:
The transmittance of light with a wavelength of 400 nm is 75% or more, the transmittance of ultraviolet light with a wavelength of 365 nm is 8% or less, and the haze value is 1% or less, before and after irradiation with 100 mW / cm ² of ultraviolet light for 20 hours. The difference in haze value is 1% or less. The ultraviolet shield according to the fourth invention.

  The manufacturing method of the ultraviolet shielding material fine particles according to the present invention has a simple process. Nevertheless, the ultraviolet shielding containing zinc oxide fine particles produced by the production method, in which the zinc element in the zinc oxide crystal is substituted and dissolved with one or more elements selected from Si, Al, Zr and Ti. By using an ultraviolet shielding material fine particle dispersion in which fine particles of material are dispersed in a medium, a conventional zinc oxide particle surface is coated to reduce the photocatalytic activity and ensure ultraviolet shielding properties. In comparison, an ultraviolet shielding material fine particle dispersion excellent in transparency, a photocatalytic activity suppressing effect, and an ultraviolet shielding property, and an ultraviolet shielding body can be obtained.

  Hereinafter, embodiments for carrying out the present invention will be described. 1. Manufacturing method of ultraviolet shielding material fine particles; 2. Ultraviolet shielding material fine particle dispersion; It demonstrates in detail in order of an ultraviolet-ray shield.

1. Manufacturing method of ultraviolet shielding material fine particles The manufacturing method of the ultraviolet shielding material fine particles according to the present invention includes the following steps (1) to (5).
(1) An aqueous solution containing one or more zinc oxide precursors selected from Zn ₅ (OH) ₆ (CO ₃ ) ₂ , ZnCO ₃ , Zn ₄ CO ₃ (OH) ₆ H ₂ O, and Zn (OH) ₂ An aqueous solution in which one or more compounds containing one or more additive elements selected from Si, Al, Zr, and Ti are dissolved is dropped, and the addition of 15% by mass to 35% by mass in terms of oxide is added. Depositing a precipitate of the zinc oxide precursor containing an elemental compound.
(2) A decantation step of washing the mixed precipitate obtained by precipitating a precipitate of the compound of the obtained zinc oxide precursor and the additive element.
However, the decantation is continuously performed until the conductivity of the liquid after cleaning becomes 1 mS / cm or less when the decantation is performed.
(3) A step of wet-treating the mixed precipitate after the decantation with an alcohol solution to obtain a wet-processed product.
(4) A step of drying the wet treated product to obtain a zinc oxide precursor-treated powder containing one or more compounds selected from Si, Al, Zr and Ti.
(5) A temperature of 300 ° C. or higher and 650 ° C. or lower in the atmosphere in which the zinc oxide precursor-treated powder is selected from the atmosphere, an inert gas, and a mixed gas of an inert gas and a reducing gas. And zinc oxide fine particles in which the zinc element in the zinc oxide crystal is substituted and dissolved by one or more elements selected from Si, Al, Zr and Ti, and the average particle size is 8.3 nm. The process of obtaining the ultraviolet shielding material fine particles comprising zinc oxide fine particles having a surface area of 15.4 nm or less and a specific surface area of 67 m ² / g to 124 m ² / g.

First, the process (1) includes one or more selected from Zn ₅ (OH) ₆ (CO ₃ ) ₂ , ZnCO ₃ , Zn ₄ CO ₃ (OH) ₆ H ₂ O, and Zn (OH) _2. An aqueous solution of an additive compound containing one or more selected from Si compounds, Al compounds, Zr compounds, and Ti compounds is dropped into an aqueous solution of a zinc oxide precursor, and 15% by mass or more and 35% by mass or less in terms of oxides. A step of depositing a mixed precipitate of the zinc oxide precursor and the additive compound will be described.

The zinc oxide precursor applied in this step is one selected from Zn ₅ (OH) ₆ (CO ₃ ) ₂ , ZnCO ₃ , Zn ₄ CO ₃ (OH) ₆ H ₂ O, and Zn (OH) _2. A zinc oxide precursor containing the above is used. The zinc oxide precursor includes, for example, an aqueous solution of a zinc compound such as zinc nitrate, zinc chloride, zinc acetate, and zinc sulfate, and an alkaline aqueous solution such as ammonium hydrogen carbonate, aqueous ammonia, sodium hydroxide, or potassium hydroxide. It is obtained by a sum reaction.
In the neutralization reaction, by dropping the aqueous solution of the zinc compound into the alkaline aqueous solution, the aqueous solution of the zinc compound instantaneously reaches the degree of supersaturation and precipitates are generated. As a result, uniform fine particles having a relatively uniform particle size can be obtained, and therefore it is necessary to obtain the zinc oxide precursor using the neutralization reaction.

On the other hand, the Si source, Al source, Zr source and Ti source to be added to the aqueous solution of the zinc oxide precursor are not particularly limited. From the viewpoint of precipitating uniform fine particles in the zinc oxide precursor, a water-soluble compound is used. Preferably there is.
Moreover, the addition amount of the compound of Si, Al, Zr, and Ti to the zinc oxide precursor is 15% by mass or more and 35% by mass or less in terms of oxide from the viewpoint of ultraviolet shielding properties and suppression of photocatalytic activity. is necessary. When the addition amount is 15% by mass or more in terms of oxide, the photocatalytic activity is sufficiently suppressed. Moreover, it is because an ultraviolet-shielding characteristic will be ensured if the addition amount is 35 mass% or less.

  There are no particular limitations on the temperature of the aqueous solution and the dropping time when adding the additive compounds to be the Si source, Al source, Zr source and Ti source to the aqueous solution of the zinc oxide precursor. Further, the pH of the aqueous solution at the completion of the addition is preferably 7.5 to 8.0 in order to stably precipitate the Si source, Al source, Zr source and Ti source. During the dropping, it is preferable to frequently stir the aqueous solution in order to make the system uniform. Moreover, after completion of the dropwise addition, it is preferable to continue the agitation to ripen the precipitate. Aging is a treatment for uniform stabilization of the precipitate.

  In the mixed precipitation of the predetermined zinc oxide precursor aged and the additive compound, the additive compound is uniformly precipitated in the zinc oxide precursor. As a result, zinc oxide fine particles substituted and dissolved in one or more elements selected from Si, Al, Zr, and Ti are obtained by performing a heat treatment process at a predetermined temperature in a predetermined atmosphere described later. Was made.

Next, a decantation step of washing the mixed precipitate obtained by depositing the obtained zinc oxide precursor and the precipitate of the additive compound, which is step (2), will be described.
The mixed precipitate obtained by aging in step (1) described above is preferably sufficiently washed by decantation using water. Specifically, the electrical conductivity of the supernatant portion in the post-cleaning solution after decantation is measured, and the cleaning is repeated until the electrical conductivity is 1 mS / cm or less. By washing until the conductivity of the supernatant of the liquid after washing is 1 mS / cm or less, impurities such as chlorine ions, nitrate ions, sulfate ions and acetate ions remaining in the mixed precipitate can be reduced. This makes it possible to avoid deteriorating the desired ultraviolet shielding property. Therefore, it is preferable to sufficiently wash the mixed precipitate until the conductivity of the supernatant portion of the washed liquid becomes 1 mS / cm or less (corresponding to a residual impurity amount of 1.5 mass% or less).

Next, the step (3) of obtaining the wet treated product by wet-treating the mixed precipitate after the decantation with an alcohol solution will be described.
The wet treatment may be performed by putting the mixed precipitate after decantation into the alcohol solution described above and stirring. In the wet treatment, the concentration of the alcohol solution is preferably 50% or more. If the concentration of the alcohol solution is 50% or more, it can be avoided that the zinc oxide fine particles become strong aggregates, and the dispersion of the zinc oxide fine particles in the solvent proceeds efficiently. It is 1% or less and exhibits excellent transparency.

  Although the alcohol used for the said wet process is not specifically limited, It is excellent in the solubility with respect to water, and alcohol with a boiling point of 100 degrees C or less is preferable. Examples include methanol, ethanol, propanol, and tert-butyl alcohol.

  In the wet treatment, the amount of the alcohol solution when the mixed precipitate is put into the alcohol solution may be a liquid amount that can easily stir the mixed precipitate and ensure fluidity. The stirring time and the stirring speed may be appropriately selected on the condition that a precipitate containing a part of the aggregate during filtration washing is uniformly mixed in the alcohol solution until there is no aggregate.

  The wet treatment may be performed at room temperature, but it is of course possible to perform the wet treatment while heating the alcohol so that the alcohol is not lost by evaporation. If heating is performed at a temperature lower than the boiling point of the alcohol, it can be avoided that the alcohol is evaporated and lost during the wetting process and the effect of the wetting process is lost. Then, it is preferable to avoid that the alcohol is evaporated and lost during the wet treatment and the wet treatment is lost, and then the wet processed product is dried and becomes a strong aggregate.

Next, the step (4) of drying the wet treated product to obtain a zinc oxide precursor-treated powder containing one or more compounds selected from Si, Al, Zr and Ti will be described.
After the wet treatment, the wet treated product is heat-dried while still wet with alcohol. Here, the drying temperature and drying time of the heat drying are not particularly limited. After the wet treatment, even if the wet treated product is dried, it does not become a strong aggregate. Therefore, the drying temperature and the drying time may be appropriately selected depending on the conditions such as the processing amount of the wet processed product and the processing apparatus.

  Finally, in step (5), the zinc oxide precursor-treated powder is 300 ° C. or higher in any atmosphere selected from the atmosphere, an inert gas, and a mixed gas of an inert gas and a reducing gas. Ultraviolet shielding material fine particles comprising zinc oxide fine particles which are heat-treated at a temperature of 650 ° C. or less and in which zinc element in the zinc oxide crystal is substituted and dissolved by one or more elements selected from Si, Al, Zr and Ti The process of obtaining

  The zinc oxide precursor-treated powder that has been dried in the above-described step (4) needs to be subjected to a heat treatment in order to improve ultraviolet shielding properties and hiding power. By performing the heat treatment, zinc oxide fine particles are obtained in which the zinc element in the zinc oxide crystal is substituted and dissolved by at least one element selected from Si, Al, Zr and Ti.

  The heat treatment is performed in an atmosphere of any one of air, an inert gas such as nitrogen, argon, and helium, or a mixed gas of the inert gas and a reducing gas such as hydrogen gas. The heat treatment temperature at this time needs to be 300 ° C. or higher and 650 ° C. or lower from the viewpoint of obtaining desired ultraviolet shielding properties. A treatment temperature of 300 ° C. or higher is preferable because heterogeneous phases are not mixed and crystallinity is increased. Moreover, if processing temperature is 650 degrees C or less, the coarsening of the particle | grains by sintering does not occur and it is preferable. On the other hand, the treatment time may be appropriately selected according to the treatment amount of the zinc oxide precursor treatment powder and the heat treatment temperature.

  Using the predetermined zinc oxide precursor-treated powder described above, by the heat treatment, zinc oxide fine particles are obtained in which zinc element is substituted and dissolved with one or more elements selected from Si, Al, Zr and Ti. .

  In the present invention, in the zinc oxide fine particles in which the zinc element in the zinc oxide crystal is substituted and dissolved with one or more elements selected from Si, Al, Zr and Ti, a predetermined amount of Si, Al, Zr and While containing one or more elements selected from Ti, the X-ray diffraction measurement results show that the diffraction peak of the compound of the additive element does not appear, only the diffraction peak of ZnO, and the ZnO single phase. It is regarded.

The obtained zinc oxide fine particles are preferably zinc oxide fine particles having an average particle diameter of 8.3 nm to 15.4 nm and a specific surface area of 67 m ² / g to 124 m ² / g. In order to obtain zinc oxide fine particles having an average particle diameter of 8.3 nm to 15.4 nm and a specific surface area of 67 m ² / g to 124 m ² / g, selected from Si, Al, Zr and Ti One or more additive compounds may be added to the zinc oxide precursor in the predetermined amount described above, and the heat treatment conditions may be set as appropriate within the range of the heat treatment conditions described above.
The average particle diameter is a value obtained from the formula: d = 6 / (ρ · SA). However, (d: average particle diameter, ρ: true density, SA: specific surface area).

  The above-described substitutional solid solution of the zinc oxide fine particles with one or more elements selected from Si, Al, Zr and Ti is a result of X-ray diffraction measurement of the zinc oxide fine particles and being a single phase of ZnO. Can be confirmed by obtaining

2. Ultraviolet shielding material fine particle dispersion The ultraviolet shielding material fine particle dispersion according to the present invention was selected from Si, Al, Zr and Ti as the zinc element in the zinc oxide crystal obtained by the above-described method for producing the ultraviolet shielding material fine particles. The zinc oxide fine particles substituted and dissolved with one or more elements, having an average particle diameter of 8.3 nm to 15.4 nm and a specific surface area of 67 m ² / g to 124 m ² / g Ultraviolet shielding material fine particles composed of fine particles are dispersed in an appropriate medium.

  As the medium, resin or glass is used. Further, the above-described ultraviolet shielding material fine particles are dispersed in an appropriate medium, and the obtained ultraviolet shielding material fine particle dispersion is formed into a film on a desired substrate surface. It is possible to adopt a method such as molding into an ultraviolet shielding material.

  Since the ultraviolet shielding material fine particles according to the present invention can be kneaded into a medium or bound to the surface of the base material by an appropriate medium, it can be formed on a base material having a low heat resistance temperature such as a resin base material. Membrane application is possible. Further, the use of the above-described ultraviolet shielding material fine particle dispersion has an advantage that a film can be formed at a low cost without requiring a large vacuum container or the like at the time of film formation.

Next, an ultraviolet shielding material fine particle dispersion according to the present invention, a production method thereof, and an application example thereof will be described.
(A) Method of dispersing ultraviolet shielding material fine particles in a medium and forming a film on the surface of the substrate Dispersing the ultraviolet shielding material fine particles according to the present invention described above in an appropriate solvent, and adding a resin as a medium thereto Thus, an ultraviolet shielding material fine particle dispersion can be obtained. Then, the ultraviolet shielding material fine particle dispersion is coated on an appropriate base material surface, the solvent is evaporated, and the resin is cured by a predetermined method, whereby the ultraviolet shielding material fine particles are dispersed in the medium resin. The fine particle dispersion can be formed into a thin film.

  The method of coating is not particularly limited. It suffices that the ultraviolet shielding material fine particle dispersion can be uniformly coated on the substrate surface, and examples thereof include a bar coating method, a spray coating method, a dip coating method, a screen printing method, a roll coating method, and a flow coating method. In addition, in the ultraviolet shielding material fine particle dispersion liquid, those having a configuration in which the ultraviolet shielding material fine particles are directly dispersed in the medium resin do not require evaporation of the solvent after coating on the surface of the substrate. Also preferred.

  As the medium described above, a UV curable resin, a thermosetting resin, an electron beam curable resin, a room temperature curable resin, a thermoplastic resin, or the like can be selected according to the purpose. Specifically, polyethylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polystyrene resin, polypropylene resin, ethylene vinyl acetate copolymer, polyester resin, polyethylene terephthalate resin, fluorine resin, polycarbonate resin, acrylic resin And polyvinyl butyral resin.

  On the other hand, the above-described base material may be in the form of a film or a board as desired, and the shape is not limited. As the transparent substrate material, polyethylene terephthalate resin, acrylic resin, urethane resin, polycarbonate resin, polyethylene resin, ethylene vinyl acetate copolymer, vinyl chloride resin, fluororesin and the like can be used according to various purposes. Moreover, glass other than resin can also be used.

(B) Method for Dispersing Ultraviolet Shielding Material Fine Particles in Medium and Forming the Dispersion The ultraviolet shielding material fine particles according to the present invention may be dispersed in the medium.
In order to disperse the ultraviolet shielding material fine particles in the medium resin, the fine particles may be permeated from the surface of the medium resin. When taking the method of permeating from the surface of the medium resin, the medium resin may be melted by raising the temperature of the medium resin to the melting temperature or higher in advance and mixed with the ultraviolet shielding material fine particles. The ultraviolet-ray shielding material fine particle dispersion thus obtained can be applied as an ultraviolet-shielding material by forming it into a film or board shape by a predetermined method.

  For example, as a method of dispersing the ultraviolet shielding material fine particles in the PET resin, first, the PET resin and the ultraviolet shielding material fine particle dispersion are mixed, and the dispersion solvent is evaporated from the mixture. Thereafter, the mixture is heated and melted to about 300 ° C. which is the melting temperature of the PET resin, the ultraviolet shielding material fine particles and the molten PET resin are kneaded, and further cooled to disperse the ultraviolet shielding material fine particles. PET resin can be obtained.

  In addition, the method of dispersing the ultraviolet shielding material fine particles in the resin is not particularly limited, and for example, it can be dispersed using ultrasonic irradiation, a bead mill, a sand mill or the like. Moreover, in order to obtain a uniform dispersion, various additives may be further added, or the pH may be adjusted.

3. Ultraviolet shielding material The ultraviolet shielding material fine particle dispersion according to the present invention may be formed into a plate shape, a film shape, or a thin film shape to form an ultraviolet shielding material.
As described above, the ultraviolet shield according to the present invention includes an ultraviolet ray containing zinc oxide fine particles in which a zinc element in a zinc oxide crystal is substituted and dissolved by at least one element selected from Si, Al, Zr, and Ti. An ultraviolet shielding material fine particle dispersion in which shielding material fine particles are dispersed in a medium is used. As a result, transparency, photocatalytic activity-suppressing effect, and UV-shielding properties were superior compared to conventional UV-shielding materials that applied a coating treatment to the surface of zinc oxide particles to suppress photocatalytic activity and ensure UV-shielding properties. An ultraviolet shield can be obtained.

In particular, the ultraviolet shield according to the present invention is excellent in that the visible light transmittance at a wavelength of 400 nm is 75% or more, the ultraviolet transmittance at a wavelength of 365 nm is 8% or less, and the haze value is 1% or less. It has optical characteristics.
Specifically, the absorption edge of the ultraviolet shield is in the ultraviolet region near the visible light, so that the visible light close to the ultraviolet light is efficiently transmitted while the ultraviolet ray is sufficiently shielded. An ultraviolet shielding body having an ultraviolet shielding profile and excellent in transparency can be obtained.

  Furthermore, by measuring the difference in transmittance before and after super UV irradiation, it is possible to see the deterioration state of the ultraviolet shielding material due to ultraviolet irradiation. However, in the ultraviolet shielding according to the present invention, the transmittance before and after super UV irradiation. Therefore, it can be confirmed that the photocatalytic activity is sufficiently suppressed.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.
The specific surface area of the ultraviolet shielding material fine particles was measured using a Macsorb manufactured by Mountec. The visible light transmittance and ultraviolet transmittance of the ultraviolet shielding material in which the ultraviolet shielding material fine particle dispersion is formed in a plate shape, a film shape or a thin film shape are measured using a spectrophotometer U-4000 manufactured by Hitachi, Ltd. It was measured.

Moreover, in order to investigate the photocatalytic activity suppression effect of the ultraviolet shielding material fine particles and the ultraviolet shielding material fine particle dispersion according to the present invention, an ultraviolet irradiation test was performed (in the present invention, sometimes referred to as “super UV irradiation”). . Specifically, using an ultraviolet irradiation device (SUV-W131 manufactured by Iwasaki Electric Co., Ltd.), the ultraviolet shielding body to be tested was irradiated with 100 mW / cm ² ultraviolet rays for 20 hours, before and after the ultraviolet irradiation. The change in the haze value in the ultraviolet shield (which may be referred to as “Δhaze” in the present invention) was measured.

[Example 1]
13.72 g of basic zinc carbonate 2ZnCO ₃ .3Zn (OH) ₂ (manufactured by Chuo Denki Kogyo) was added to 100 ml of water at 40 ° C. and stirred, and water glass No. 1 (SiO ₂ concentration 36.5% by mass) was added here An aqueous solution obtained by diluting 6.85 g with 100 ml of water was dropped over about 40 minutes. Stirring was continued for 2 minutes after completion of the dropping, and 17.6% by mass nitric acid was added dropwise so as to have a pH of 7.5 to 8.0 to form a precipitate. After completion of the dropping, stirring was further continued for 10 minutes to age the precipitate. The final pH at this time was 7.5.

  Next, the precipitate was repeatedly washed by decantation until the electrical conductivity of the supernatant liquid after washing was 1 mS / cm or less. Thereafter, the washed precipitate is immersed in denatured alcohol (manufactured by Nippon Alcohol Sales Co., Ltd., Solmix AP-2 (trade name)) (may be described as “AP-2” in the present invention). Wet treatment and drying at 105 ° C. gave a dry powder.

Next, the dry powder was heat-treated in the atmosphere at a temperature of 400 ° C. for 1 hour to obtain 20% SiO ₂ -treated ZnO fine particles a. Since the amount of ZnO contained in the dry powder is 10.17 g and the amount of SiO ₂ is 2.50 g, the proportion of SiO _{2 in} the dried product is
2.50 / (10.17 + 2.50) × 100 = 19.7% by mass
Therefore, the dry powder is expressed as 20% SiO ₂ -treated ZnO fine particles a.

As a result of performing X-ray diffraction measurement (may be described as “XRD measurement” in the present invention) on the 20% SiO ₂ -treated ZnO fine particles a obtained by the heat treatment described above, it is a single phase of ZnO. It has been found. Thus, it was confirmed that the 20% SiO ₂ treated ZnO fine particles a according to Example 1 were zinc oxide fine particles in which the zinc element was substituted and dissolved by the Si element.
The specific surface area of the 20% SiO ₂ -treated ZnO fine particles a was 94.1 m ² / g, and the average particle size was 11.0 nm.

Next, 7.5% by mass of 20% SiO ₂ treated ZnO fine particles a (ZnO equivalent), 2.25% by mass of acrylic dispersant, and the remaining toluene, 0.3 mm zirconia beads corresponding to a filling rate of 80%. The mixture was loaded into a paint shaker and dispersed for 10 hours to obtain dispersion A.

  After thoroughly mixing 66.7% by mass of the dispersion A and 33.3% by mass of the UV curable resin to obtain a mixed solution, the mixed solution was applied onto a 3 mm thick clear glass substrate using a bar of count 40. Was applied. The coated surface was irradiated with ultraviolet rays from a high-pressure mercury lamp at 70 ° C. for 1 minute to obtain an ultraviolet shield A according to Example 1.

The ultraviolet light shielding material A thus obtained was measured for the visible light transmittance, the light transmittance in the visible region of wavelength 400 nm, the light transmittance in the ultraviolet region of wavelength 365 nm, and the haze value.
Furthermore, the haze value after 20 hours of super UV irradiation on the ultraviolet shield A was measured, and Δ haze before and after UV irradiation was determined.

Table 1 shows the outline of the manufacturing conditions of the 20% SiO ₂ -treated ZnO fine particles, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the characteristic measurement results of the ultraviolet shielding material.

[Example 2]
30% SiO ₂ treated ZnO fine particles b according to Example 2 by performing the same operation as in Example 1, except that the amount of water glass No. 1 (SiO ₂ concentration: 36.5% by mass) dropped to 11.75 g. Dispersion B and ultraviolet shield B were obtained.

As a result of X-ray diffraction measurement of the 30% SiO ₂ -treated ZnO fine particles b obtained by the heat treatment described above, it was found to be a single phase of ZnO. Thus, it was confirmed that the 30% SiO ₂ -treated ZnO fine particles b according to Example 2 were zinc oxide fine particles in which the zinc element was substituted and dissolved by the Si element.
The specific surface area of the 30% SiO ₂ -treated ZnO fine particles b was 104.1 m ² / g, and the average particle size was 9.9 nm.

By the same operation as in Example 1, the obtained ultraviolet light shielding body B was measured for the visible light transmittance, the light transmittance in the visible region with a wavelength of 400 nm, the light transmittance in the ultraviolet region with a wavelength of 365 nm, and the haze value.
Furthermore, the haze value after 20 hours of super UV irradiation on the ultraviolet shield B was measured, and Δ haze before and after UV irradiation was determined.

Table 1 shows an outline of the manufacturing conditions of the 30% SiO ₂ -treated ZnO fine particles, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the characteristic measurement results of the ultraviolet shielding material.

[Example 3]
13.72 g of basic zinc carbonate (manufactured by Chuo Denki Kogyo Co., Ltd.) was added to 100 ml of water at 40 ° C. and stirred, and 5.14 g of water glass No. 1 (SiO ₂ concentration 36.5% by mass) was added to 100 ml of water. The diluted aqueous solution was added dropwise over about 40 minutes. After completion of the dropping, stirring was continued for 2 minutes, and then an aqueous solution in which 4.56 g of aluminum nitrate nonahydrate was dissolved in 100 ml of water was dropped over about 40 minutes to form a precipitate. At this time, 7% aqueous ammonia was appropriately added dropwise so that the pH in the liquid was 7.5 to 8.0. After completion of the dropping, stirring was further continued for 10 minutes to age the precipitate. The final pH at this time was 7.7.

Next, the precipitate was repeatedly washed by decantation until the electrical conductivity of the supernatant liquid after washing was 1 mS / cm or less. Thereafter, the washed precipitate was dipped in AP-2, wet-treated, dried at 105 ° C. to obtain a dry powder, and the same operation as in Example 1 was performed. % SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles c, dispersion C and ultraviolet shield C were obtained.

As a result of X-ray diffraction measurement of the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles c obtained by the heat treatment, it was found to be a single phase of ZnO. Thus, it was confirmed that the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles c according to Example 3 were zinc oxide fine particles in which a zinc element was substituted and dissolved by Si and Al elements.
The specific surface area of the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles c was 90.4 m ² / g, and the average particle size was 11.4 nm.

By the same operation as in Example 1, the obtained ultraviolet light shielding body C was measured for the visible light transmittance, the light transmittance in the visible region of wavelength 400 nm, the light transmittance in the ultraviolet region of wavelength 365 nm, and the haze value.
Furthermore, the haze value after 20 hours of super UV irradiation on the ultraviolet shield C was measured, and Δ haze before and after UV irradiation was determined.
Table 1 shows the outline of the manufacturing conditions of the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles c, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the characteristic measurement results of the ultraviolet shielding material.

[Example 4]
15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles d according to Example 4, dispersion D and ultraviolet shielding material, except that the firing temperature of the dry powder was 500 ° C. D was obtained.

As a result of X-ray diffraction measurement of the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles d obtained by the heat treatment described above, it was found to be a single phase of ZnO. Thus, it was confirmed that the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles d according to Example 4 were zinc oxide fine particles in which a zinc element was substituted and dissolved by Si and Al elements.
The specific surface area of the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles d was 81.4 m ² / g, and the average particle size was 12.7 nm.

By the same operation as in Example 1, the obtained ultraviolet shielding material D was measured for the visible light transmittance, the light transmittance in the visible region of wavelength 400 nm, the light transmittance in the ultraviolet region of wavelength 365 nm, and the haze value.
Furthermore, the haze value after 20 hours of super UV irradiation on the ultraviolet shield D was measured, and Δ haze before and after UV irradiation was determined.
Table 1 shows the outline of the manufacturing conditions of the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles d, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the characteristic measurement results of the ultraviolet shielding material.

[Example 5]
15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles e, dispersion E according to Example 5 except that the firing temperature of the zinc oxide precursor dry powder was 600 ° C. And the ultraviolet shielding body E was obtained.

As a result of X-ray diffraction measurement of the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles e obtained by the heat treatment described above, it was found to be a single phase of ZnO.
Accordingly, it was confirmed that the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles e according to Example 5 were zinc oxide fine particles in which the zinc element was substituted and dissolved by the Si and Al elements.
The specific surface area of the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles e was 78.6 m ² / g, and the average particle size was 13.2 nm.

By the same operation as in Example 1, the obtained ultraviolet shielding E was measured for the visible light transmittance, the light transmittance in the visible region with a wavelength of 400 nm, the light transmittance in the ultraviolet region with a wavelength of 365 nm, and the haze value.
Furthermore, the haze value after 20 hours of super UV irradiation on the ultraviolet shield E was measured, and Δ haze before and after UV irradiation was determined.
Table 1 shows an outline of the manufacturing conditions of the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles e, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the characteristic measurement results of the ultraviolet shielding material.

[Example 6]
Except for water glass No. 1 (SiO ₂ concentration 36.5%) 5.14 g, the same operation as in Example 1 was performed, and 15% SiO ₂ treated ZnO fine particles f according to Example 6, dispersion F and An ultraviolet shield F was obtained.

As a result of X-ray diffraction measurement of the 15% SiO ₂ -treated ZnO fine particles f obtained by the heat treatment described above, it was found to be a single phase of ZnO.
As a result, it was confirmed that the 15% SiO ₂ -treated ZnO fine particles f were zinc oxide fine particles in which the zinc element was substituted and dissolved by the Si element.
The specific surface area of the 15% SiO ₂ -treated ZnO fine particles f was 69.6 m ² / g, and the average particle size was 14.9 nm.

By the same operation as in Example 1, the obtained ultraviolet shielding F was measured for the visible light transmittance, the light transmittance in the visible region of wavelength 400 nm, the light transmittance in the ultraviolet region of wavelength 365 nm, and the haze value.
Furthermore, the haze value after 20 hours of super UV irradiation on the ultraviolet shield F was measured, and Δ haze before and after UV irradiation was determined.
Table 1 shows an outline of the manufacturing conditions of the 15% SiO ₂ -treated ZnO fine particles f, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the characteristic measurement results of the ultraviolet shielding material.

[Comparative Example 1 and Comparative Example 2]
10% SiO ₂ treated ZnO fine particles g according to Comparative Example 1 were obtained by performing the same operation as in Example 1 except that the amount of water glass No. 1 (SiO ₂ concentration: 36.5% by mass) was 3.42 g. Dispersion G and ultraviolet shield G were obtained.
In addition, the same operation as in Example 1 was performed except that water glass No. 1 (SiO ₂ concentration of 36.5% by mass) was not dropped, and ZnO fine particles h, dispersion H and ultraviolet shielding according to Comparative Example 2 were performed. Body H was obtained.

As a result of X-ray diffraction measurement of the 10% SiO ₂ -treated ZnO fine particles g according to Comparative Example 1 obtained by the heat treatment described above, it was found to be a single phase of ZnO.
Thus, it was confirmed that the 10% SiO ₂ -treated ZnO fine particles g were zinc oxide fine particles in which the zinc element was substituted and dissolved by the Si element.
The specific surface area of the 10% SiO ₂ -treated ZnO fine particles g was 66.5 m ² / g, and the average particle size was 15.6 nm.

As a result of X-ray diffraction measurement of the ZnO fine particles h according to Comparative Example 2 obtained by the heat treatment described above, it was found to be a single phase of ZnO.
The specific surface area of the ZnO fine particles h was 30.9 m ² / g, and the average particle size was 33.5 nm.

By the same operation as in Example 1, the visible light transmittance of the obtained ultraviolet shields G and H, the light transmittance in the visible region of wavelength 400 nm, the light transmittance in the ultraviolet region of wavelength 365 nm, and the haze value were measured. did. Furthermore, the haze value after 20 hours of super UV irradiation to the ultraviolet shields F and G was measured, and Δ haze before and after UV irradiation was determined.
Table 1 shows an outline of the manufacturing conditions of the 10% SiO ₂ -treated ZnO fine particles g, ZnO fine particles h, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the measurement results of the characteristics of the ultraviolet shielding material.

[Comparative Example 3]
Silica-alumina-treated zinc oxide (NANOFINE 50A, BET specific surface area 50 m ² / g, manufactured by Sakai Chemical Co., Ltd.) 7.5% by mass (ZnO conversion), acrylic dispersant 2.25% by mass, and remaining toluene composition Except that, the same operation as in Example 1 was performed to obtain SiO ₂ · Al ₂ O ₃ -coated ZnO fine particles i, dispersion I, and ultraviolet shield I according to Comparative Example 3.
The specific surface area of the SiO ₂ · Al ₂ O ₃ -coated ZnO fine particles i was 60.7 m ² / g, and the average particle size was 17.0 nm.

The visible light transmittance of the ultraviolet shield I obtained by the same operation as in Example 1, the light transmittance in the visible region of wavelength 400 nm, the light transmittance in the ultraviolet region of wavelength 365 nm, and the haze value were measured. Furthermore, the haze value after 20 hours of super UV irradiation of the ultraviolet shielding body H was measured, and Δ haze before and after UV irradiation was determined.
Table 1 shows an outline of the manufacturing conditions of the compound-doped ZnO fine particles, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the measurement results of the properties of the ultraviolet shielding material.

[Example 7]
1100 g of an aqueous solution containing 86.9 g of ammonium hydrogen carbonate (special grade) was prepared, and 946.1 g of an aqueous solution containing 148.4 g of zinc nitrate hexahydrate (special grade) was stirred at 25 ° C. over 6 minutes. A precipitate was formed by dropwise addition. Here water glass No. 1 and (SiO ₂ concentration 36.5 wt%) 5.14 g was added dropwise over about 40 minutes an aqueous solution prepared by diluting with water 100 ml, and stirring was continued for 2 minutes after dropwise addition. Thereafter, an aqueous solution in which aluminum nitrate nonahydrate was dissolved in 100 ml of water was dropped over about 40 minutes. At this time, 7% aqueous ammonia was appropriately added dropwise so that the pH in the liquid was 7.5 to 8.0. After completion of the dropping, stirring was further continued for 10 minutes to age the precipitate. The final pH at this time was 7.5.

  Next, the precipitate was repeatedly washed by decantation until the electrical conductivity of the supernatant liquid after washing was 1 mS / cm or less. Thereafter, the washed precipitate was dipped in AP-2 and wet-treated, and dried at 105 ° C. to obtain a dry powder.

As a result of measuring the structure of the dry powder by XRD, it was a mixed phase of ZnCO ₃ , Zn ₄ CO ₃ (OH) ₆ H ₂ O and Zn ₅ (OH) ₆ (CO ₃ ) ₂ .

Except for using the dry powder, the same operation as in Example 3 was performed to obtain 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles j, dispersion J, and ultraviolet shield J according to Example 7. It was.

As a result of X-ray diffraction measurement of the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles j obtained by the heat treatment described above, it was found to be a single phase of ZnO. Thus, it was confirmed that the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles j according to Example 7 were zinc oxide fine particles in which a zinc element was substituted and dissolved by Si and Al elements.
The specific surface area of the 15% SiO ₂ + 5% Al ₂ O ₃ treated ZnO fine particles j was 90.6 m ² / g, and the average particle size was 11.4 nm.

The ultraviolet light shielding material J thus obtained was measured for visible light transmittance, visible wavelength transmittance of 400 nm, ultraviolet wavelength transmittance of 365 nm, and haze value. Furthermore, the haze value after 20 hours of super UV irradiation of the ultraviolet shielding body H was measured, and Δ haze before and after UV irradiation was determined.
Table 1 shows an outline of the manufacturing conditions of the compound-doped ZnO fine particles, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the measurement results of the properties of the ultraviolet shielding material.

[Example 8, Comparative Examples 4 to 6]
Except that the firing temperature was 350 ° C., the same operation as in Example 1 was performed to obtain 20% SiO ₂ -treated ZnO fine particles k, dispersion K, and ultraviolet shield K according to Example 8.
Further, the same operation as in Example 1 was performed except that the firing temperature was set to 300 ° C., so that 20% SiO ₂ treated ZnO fine particles 1, dispersion L and ultraviolet shielding body L according to Comparative Example 4 were obtained.
Then, the same operation as in Example 1 was performed except that the firing temperature was set to 650 ° C., to obtain 20% SiO ₂ -treated ZnO fine particles m, dispersion M, and ultraviolet shield M according to Comparative Example 5.
Further, the same operation as in Example 1 was performed except that the firing temperature was set to 700 ° C., so that 20% SiO ₂ -treated ZnO fine particles n, dispersion N and ultraviolet shielding body N according to Comparative Example 6 were obtained.

The obtained 20% SiO ₂ treated ZnO fine particles k according to Example 8 were subjected to X-ray diffraction measurement, and as a result, it was found to be a single phase of ZnO.
Thus, it was confirmed that the 20% SiO ₂ -treated ZnO fine particles k according to Example 8 were zinc oxide fine particles in which the zinc element was substituted and dissolved by the Si element.

Further, as a result of X-ray diffraction measurement of the obtained 20% SiO ₂ -treated ZnO fine particles 1 according to Comparative Example 4, a broad peak thought to be a SiO ₂ phase other than ZnO was observed.
Thus, it was confirmed that the 20% SiO ₂ -treated ZnO fine particles k according to Comparative Example 4 were not zinc oxide fine particles in which the zinc element was substituted and dissolved by the Si element.

Then, 20% SiO ₂ treated ZnO particles m of Comparative Example 5 obtained, and, for 20% SiO ₂ treated ZnO particle n according to Comparative Example 6, results of X-ray diffraction measurement, ZnO single phase of It turned out to be.
Thus, 20% SiO ₂ treated ZnO particle m according to Comparative Example 5, and, 20% SiO ₂ treated ZnO particle n in accordance with Comparative Example 6, a zinc oxide fine particle zinc element is substituted solid solution with Si element It was confirmed that

The specific surface area of the 20% SiO ₂ -treated ZnO fine particles k according to Example 8 was 100.4 m ² / g, and the average particle size was 10.3 nm.
The specific surface area of the 20% SiO ₂ -treated ZnO fine particles 1 according to Comparative Example 4 was 97.5 m ² / g, and the average particle size was 10.6 nm.
The specific surface area of the 20% SiO ₂ -treated ZnO fine particles m according to Comparative Example 5 was 50.4 m ² / g, and the average particle size was 20.5 nm.
The specific surface area of 20% SiO ₂ -treated ZnO fine particles n according to Comparative Example 6 was 34.1 m ² / g, and the average particle size was 30.3 nm.

By the same operation as in Example 1, the visible light transmittance of the ultraviolet shielding bodies K to N obtained in Example 8 and Comparative Examples 4 to 6, the light transmittance in the visible region of wavelength 400 nm, the wavelength 365 nm. The light transmittance and haze value in the ultraviolet region were measured. Furthermore, the haze value after 20 hours of super UV irradiation of the ultraviolet shielding bodies K to N was measured, and Δ haze before and after UV irradiation was obtained.
Table 1 shows an outline of the manufacturing conditions of the compound-doped ZnO fine particles, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the measurement results of the properties of the ultraviolet shielding material.

[Example 9]
13.72 g of basic zinc carbonate (manufactured by Chuo Denki Kogyo Co., Ltd.) was added to 100 ml of water at 40 ° C. and stirred, and an aqueous solution in which 7.21 g of zirconium sulfate tetrahydrate was dissolved in 100 ml of water, and 7% aqueous ammonia Were simultaneously dripped over about 40 minutes. At this time, 20% ZrO according to Example 9 was obtained by performing the same operation as in Example 1 except that 7% ammonia water was appropriately added dropwise so that the pH in the liquid was 7.5 to 8.0. _Two- processed ZnO fine particles o, a dispersion O and an ultraviolet shield O were obtained.

As a result of X-ray diffraction measurement of the 20% ZrO ₂ -treated ZnO fine particles o obtained by the heat treatment described above, it was found to be a single phase of ZnO.
Thus, it was confirmed that the 20% ZrO ₂ -treated ZnO fine particles o according to Example 9 were zinc oxide fine particles in which a zinc element was substituted and dissolved by a Zr element.
The specific surface area of the 20% ZrO ₂ -treated ZnO fine particles o according to Example 9 was 68.2 m ² / g, and the average particle size was 15.2 nm.

By the same operation as in Example 1, the obtained ultraviolet shielding body O was measured for the visible light transmittance, the light transmittance in the visible region of wavelength 400 nm, the light transmittance in the ultraviolet region of wavelength 365 nm, and the haze value. Furthermore, the haze value after 20 hours of super UV irradiation of the ultraviolet shield O was measured, and Δ haze before and after UV irradiation was obtained.
Table 1 shows an outline of the manufacturing conditions of the compound-doped ZnO fine particles, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the measurement results of the properties of the ultraviolet shielding material.

[Example 10]
13.72 g of basic zinc carbonate (manufactured by Chuo Denki Kogyo Co., Ltd.) was added to 100 ml of water and stirred, and an aqueous solution obtained by diluting 5.14 g of water glass No. 1 (SiO ₂ concentration 36.5% by mass) with 100 ml of water. Was dropped over about 40 minutes. After the dropping, stirring was continued for 2 minutes, and then an aqueous solution in which 1.49 g of a titanium tetrachloride solution was dissolved in 100 ml of water was dropped over about 40 minutes. At this time, 7% by mass of ammonia water was appropriately added dropwise so that the pH in the liquid was 7.5 to 8.0. After completion of the dropping, stirring was further continued for 10 minutes to age the precipitate. The final pH at this time was 7.7.

Next, a 15% SiO ₂ + 5% TiO ₂ -treated ZnO fine particle p according to Example 10 was obtained by performing the same operation as in Example 3 except that decantation was performed until the electric conductivity of the liquid after washing became 1 mS / cm or less. Dispersion P and ultraviolet shield P were obtained.

As a result of X-ray diffraction measurement of the 15% SiO ₂ + 5% TiO ₂ -treated ZnO fine particles p obtained by the heat treatment described above, it was found to be a single phase of ZnO.
Thus, it was confirmed that the 15% SiO ₂ + 5% TiO ₂ -treated ZnO fine particles p according to Example 10 were zinc oxide fine particles in which a zinc element was substituted and dissolved by Si and Ti elements. The specific surface area of the 15% SiO ₂ + 5% TiO ₂ -treated ZnO fine particles p according to Example 10 was 86.2 m ² / g, and the average particle size was 12.0 nm.

By the same operation as in Example 1, the visible light transmittance, the visible transmittance at a wavelength of 400 nm, the transmittance in the ultraviolet region at a wavelength of 365 nm, and the haze value of the obtained ultraviolet shield P were measured. Furthermore, the haze value after 20 hours of super UV irradiation of the ultraviolet shield C was measured, and Δ haze before and after UV irradiation was determined.
Table 1 shows an outline of the manufacturing conditions of the compound-doped ZnO fine particles, the ultraviolet shielding material fine particle dispersion, and the ultraviolet shielding material, and Table 2 shows the measurement results of the properties of the ultraviolet shielding material.

[Evaluation]
In Table 2, the visible light transmittance, the light transmittance in the visible region with a wavelength of 400 nm, the light transmittance in the ultraviolet region with a wavelength of 365 nm, the haze value, and the Δhaze before and after irradiation of the ultraviolet shield for Super UV 20 hours , Dispersions A to F, J, K, O, and P according to Examples 1 to 10 using fine particles a to f and j, k, o, and p, and ultraviolet shields A to F prepared from the dispersions Dispersions G to I and L to N according to Comparative Examples 1 to 6 using F, J, K, O, and P and fine particles g to i and l to n, an ultraviolet shield prepared from the dispersion G to I and L to N were compared.

  As a result, the ultraviolet shields A to F, J, K, O, and P according to Examples 1 to 10 have a high transparency of 75% or more in the visible region at a wavelength of 400 nm, and transmit the ultraviolet region at a wavelength of 365 nm. The rate is 8% or less, Δhaze is 1.0% or less, transparency and UV shielding are excellent, Δhaze before and after super UV 20 hours irradiation is 1% or less, and photocatalytic activity is sufficiently suppressed. It is clear that

  On the other hand, in the ultraviolet shielding bodies G and H according to Comparative Examples 1 and 2, Δhaze before and after the super UV 20-hour irradiation both exceeds 2%, and the ultraviolet shielding body I according to Comparative Example 3 is in the ultraviolet region with a wavelength of 365 nm. The light transmittance was as high as 10%, and the Δhaze before and after irradiation with Super UV for 20 hours exceeded 1%.

Moreover, the ultraviolet light shielding body L according to Comparative Example 4 has a light transmittance in the ultraviolet region with a wavelength of 365 nm close to that of Comparative Example 3 and exceeds 9%. This is because, in Comparative Example 4, zinc oxide fine particles in which zinc element is substituted and dissolved in Si element are not formed, and other phases that are considered to be SiO ₂ phases are formed in addition to ZnO, so that the optical characteristics have been conventionally improved. It is presumed that it became close to the coated product.
The ultraviolet shields M and N according to Comparative Examples 5 and 6 have a light transmittance of less than 70% in the visible region with a wavelength of 400 nm, and the initial haze value of the ultraviolet shield N exceeds 1%. there were.

Claims (5)

To an aqueous solution containing one or more zinc oxide precursors selected from Zn ₅ (OH) ₆ (CO ₃ ) ₂ , ZnCO ₃ , Zn ₄ CO ₃ (OH) ₆ H ₂ O, Zn (OH) ₂ , Si An aqueous solution in which one or more compounds containing one or more additive elements selected from Al, Zr, and Ti are dissolved is dropped, and the compound of the additive element is 15% by mass or more and 35% by mass or less in terms of oxide Depositing a precipitate of the zinc oxide precursor comprising:
A decantation step of washing the deposited precipitate and continuing washing until the conductivity of the solution after washing becomes 1 mS / cm or less;
The washed precipitate is wet-treated with an alcohol solution to obtain a wet-processed product, and then the wet-processed product is dried to contain a zinc oxide precursor containing one or more compounds selected from Si, Al, Zr and Ti. Obtaining body treatment powder;
The zinc oxide precursor-treated powder is heat-treated at a temperature of 300 ° C. or higher and 650 ° C. or lower in any atmosphere selected from the atmosphere, an inert gas, and a mixed gas of an inert gas and a reducing gas. In addition, zinc oxide fine particles in which zinc element in the zinc oxide crystal is substituted and dissolved by one or more elements selected from Si, Al, Zr and Ti, and the average particle diameter is 8.3 nm or more and 15.4 nm or less And a step of obtaining ultraviolet shielding material fine particles containing zinc oxide fine particles having a specific surface area of 67 m ² / g or more and 124 m ² / g or less. Zinc oxide fine particles in which zinc element in the zinc oxide crystal is substituted and dissolved by one or more elements selected from Si, Al, Zr and Ti,
Ultraviolet shielding material fine particles including the zinc oxide fine particles having an average particle diameter of 8.3 nm to 15.4 nm and a specific surface area of 67 m ² / g to 124 m ² / g are dispersed in a medium. Ultraviolet shielding material fine particle dispersion characterized.   The ultraviolet ray shielding material fine particle dispersion according to claim 2, wherein the medium is resin or glass.   The ultraviolet shielding material fine particle dispersion according to any one of claims 2 and 3, wherein the ultraviolet shielding material fine particle dispersion is processed into any shape selected from a plate shape, a film shape, and a thin film shape. Shield. The transmittance of light with a wavelength of 400 nm is 75% or more, the transmittance of ultraviolet light with a wavelength of 365 nm is 8% or less, and the haze value is 1% or less, before and after irradiation with 100 mW / cm ² of ultraviolet light for 20 hours. The ultraviolet shielding body according to claim 4, wherein a difference in haze value is 1% or less.