JP4599856B2 - Coated particles - Google Patents

Description

  The present invention relates to coated particles in which one or more nanosheet layers are laminated around template particles or hollow portions.

  Conventionally, coat particles in which template particles are coated with titanium oxide are known. The coated particles were produced by immersing template particles in a sol obtained by hydrolyzing titanium sulfate, titanium alkoxide, or the like. In the sol, titanium oxide particles are dispersed as colloidal particles having a diameter of several nanometers or more, and the resulting coated particles are obtained by closely gathering spherical titanium oxide particles on template particles.

In addition, as shown in FIG. 11, in recent years, particles made of polystyrene (PS) or polymethyl methacrylate (PMMA) are used as template particles 91, and nanosheet layers 95 and polymers in which nanosheets made of titanium oxide are assembled on the template particles 91. Coated particles 9 in which the resin layers 93 made of the material were alternately laminated were synthesized. In such coated particles, hollow coated particles from which template particles have been removed can be produced by further heat treatment or UV irradiation. For example, in the hollow particles heat-treated at a temperature of 500 ° C., the titanium oxide nanosheets crystallize into anatase type, and the light absorption thereof shows the same behavior as that of bulk anatase type titanium oxide. On the other hand, the hollow particles subjected to UV irradiation do not proceed with crystallization, and the hollow particles composed only of the titanium oxide nanosheets are synthesized (see Non-Patent Document 1).
Since the coated particles as described above can absorb ultraviolet light, for example, they are expected to be used as a coating agent that shields ultraviolet light.

  However, the coated particles described in Non-Patent Document 1 have a problem that although the wavelength of 265 nm is absorbed with high efficiency, the absorption efficiency in other wavelength regions is low and UV rays cannot be sufficiently absorbed. .

TakayoshiSasaki, 4 others, Fabrication of Controllable Ultrathin Hollow Shells by Layer-by-Layer Assembly of Exfoliated Titania Nanosheets on Polymer Templates, Chemistry of Materials, USA, American Chemical Society, 2002, Vol. 14, No. 11, p. 4827-4832

  The present invention has been made in view of such conventional problems, and is intended to provide coated particles capable of absorbing ultraviolet light in a wide range.

A first aspect of the present invention is around the template particles with a diameter of 0.01 to 10 m, the nanosheet layer made of Na Noshito is a coated particle that are stacked one or more layers,
The _{nanosheet, Ti 2-x Me x O} 4 (Me is Ni, Co, Cu, Zn, and one or more selected from Fe, x is 0.4 or 0.8) Tona is,
The coated particle is characterized in that a resin layer made of a cationic polymer electrolyte is formed between the nanosheet layer and the template particle .

The second invention is a coated particle in which a single layer or a plurality of nanosheet layers made of nanosheets of monomolecular layers are laminated around a hollow portion having a diameter of 0.01 μm to 10 μm,
The _{nanosheet, Ti 2-x Me x O} 4 (Me is Ni, Co, Cu, Zn, and one or more selected from Fe, x is 0.4 or 0.8), characterized in that it consists of coating In the particles (claim 4 ).

In the coated particles of the first and second inventions, the nanosheet is Ti _2-x Me _x O ₄ (Me is one or more selected from Ni, Co, Cu, Zn, and Fe, and x is 0.4). Or 0.8). Ti _2-x Me _x O ₄ is obtained by replacing at least part of Ti in Ti ₂ O ₄ with Me.
Therefore, the coated particle has an absorption wavelength derived from Me in the composition of the nanosheet. Therefore, the nanosheet exhibits high efficiency absorption in a wavelength region of 300 nm or less, and the coated particles can also absorb ultraviolet light in a wide region of 300 nm or less.
Thus, according to the present invention, coated particles capable of absorbing ultraviolet light in a wide range can be provided.

Further, the coated particle is formed by laminating a nanosheet layer made of, for example, a monomolecular nanosheet around a very small template particle having a diameter of 0.01 μm to 10 μm. Therefore, the coated particles can serve as colloidal particles. The coated particles can be colored by an interference effect by appropriately controlling the diameter of the template particles and the number of stacked nanosheet layers. Therefore, it can be used as, for example, various colorants and paints.

The coated particles of the first invention have the template particles. Therefore, when the coated particles are produced, the coated particles can be easily produced by forming the nanosheet layer around the template particles by, for example, a layer-by-layer method.
On the other hand, the coated particle of the second invention has the hollow portion. For this reason, the coating particles can be reduced in weight.
The coated particles having the hollow portion as in the second invention can be obtained, for example, by removing the template particles in the coated particles of the first invention.

  In the first invention, the template particles have a diameter of 0.01 μm to 10 μm. When the diameter of the template particles is less than 0.01 μm, it becomes difficult to coat the nanosheets around the template particles in a monodispersed state when forming the coated particles, thereby forming secondary particles. There is a risk that. On the other hand, when the thickness exceeds 10 μm, for example, when the coated particles are produced and then the template particles are removed to produce coated particles having hollow portions, the nanosheet layer may be deformed.

The nanosheet can be obtained, for example, by peeling a layered crystal of Ti _2-x Me _x O ₄ up to a monomolecular layer. At this time, the thickness of the monomolecular layer is approximately 0.5 nm to 1.5 nm. The nanosheet has a flaky shape, for example.

The coated particles can be produced by, for example, collecting the nanosheets around the template particles and forming the nanosheet layer by electrical interaction in a dispersion medium such as water.
The nanosheet is made of Ti _2-x Me _x O ₄ and can be negatively charged in a dispersion medium such as water.

  As the template particles, for example, those having a positive charge or a negative charge in a dispersion medium such as water can be used. Specifically, the positively charged template particles include, for example, those made of polystyrene (PS), polymethyl methacrylate (PMMA), or the like. Examples of the template particles having negative charges include those made of silica, polystyrene (PS), polymethyl methacrylate (PMMA), and the like.

When the template particles are positively charged in the dispersion medium, the nanosheets can be easily assembled around the template particles by electrical interaction.
On the other hand, when the template is negatively charged in the dispersion medium, it is difficult to aggregate the nanosheets around the template particles to form the nanosheet layer.

Therefore, in the first invention, it is preferable that a resin layer made of a cationic polymer electrolyte is formed between the nanosheet layer and the template particles .
In this case, when the coated particles are prepared, the negatively charged template particles are used in the same manner even in the case of using negatively charged template particles in a dispersion medium such as silica (SiO ₂ ) or polymethyl methacrylate (PMMA). The coated particles can be easily produced by assembling nanosheets made of Ti _2-x Me _x O ₄ around the template particles.
Examples of the cationic polymer electrolyte include amine polymers such as polyethyleneimine (PEI) and polyallylamine.

Moreover, it is preferable that the said template particle consists of silica (Claim 2 ).
In this case, the template particles can be easily removed by heating in a sodium hydroxide aqueous solution or etching with a hydrofluoric acid aqueous solution. The coated particles having the above can be easily produced.
In this case, since the particle diameters are uniform, for example, the particles can be regularly arranged when a colloidal crystal is produced.

Furthermore, the templates particles is preferably made of polymethyl methacrylate or polystyrene (claim 3).
Also in this case, it is possible to easily obtain the coated particles of the second invention by removing the template particles from the coated particles of the first invention. Template particles made of polymethylmethacrylate and / or polystyrene can be easily extracted and removed with an organic solvent such as tetrahydrofuran (THF), for example, so that the template particles in the second invention can be used instead of the template particles in the first invention. This is because the hollow portion can be easily formed.
In this case, since the particle diameters are uniform, for example, the particles can be regularly arranged when a colloidal crystal is produced.

In the second invention, the hollow portion has a diameter of 0.01 μm to 10 μm. As described above, the hollow portion can be formed by removing the template particles from the coated particles of the first invention. Therefore, the critical significance of the diameter of the hollow portion is the same as the critical significance of the diameter of the template particle.
Further, from the formation on the convenience of the coated particles as described above, is between the nanosheet layer and the hollow portion, it is preferable that a resin layer comprising a cationic polymer electrolyte is formed (claim 5 ).

In the first and second inventions, the nanosheet layer preferably are formed by combining the nanosheet width 5 nm to 500 nm (claim 6).
In this case, when the coated particles are produced, there is almost no gap between the nanosheets, and the nanosheet layer having a uniform thickness can be formed. As a result, the particle size uniformity of the coated particles is very high. Become. Therefore, in this case, for example, the above-mentioned coated particles can be regularly arranged to produce a colloidal crystal.

When the width of the nanosheet is less than 5 nm, for example, the nanosheet was dispersed in a dispersion medium such as water, and the nanoparticle was dispersed when preparing the coated particles by adding and mixing template particles thereto. There is a possibility that the viscosity of the dispersion medium becomes high and it becomes difficult to uniformly mix with the template particles. On the other hand, when the thickness exceeds 500 nm, the nanosheets overlap each other when forming the nanosheet layer by gathering the nanosheets around the template particles, for example, by a layer-by-layer method or the like, and the thickness of the nanosheet layer is increased. May become uneven. In addition, a gap is easily generated in the nanosheet layer. As a result, the particle size uniformity of the coated particles may be reduced.
Here, the width of the nanosheet can be expressed by, for example, an average of the maximum width and the minimum width of the nanosheet.

Further, the nanosheet layer are preferably a plurality of layers laminated (claim 7).
In this case, the interference effect of the coated particles can be controlled according to the number of stacked nanosheet layers. Therefore, the coated particles can be used as various colorants, paints and the like.

Hereinafter, the method of laminating a plurality of the nanosheets will be described separately for a case where a template particle having a negative charge is used and a case where a template particle having a positive charge is used.
When the template particles are made of, for example, silica (SiO ₂ ) or PMMA and have a negative charge in the dispersion medium, the template particles are first made of a cationic polymer electrolyte such as polyethyleneimine (PEI). The resin layer is formed on the surface of the template particle by dipping in a resin solution. Then, tinged with sol dispersed nanosheets composed of Ti _2-x Me _x O ₄ above, were mixed with the template particles forming the resin layer, the negative charges on the surface of the resin layer positively charged The nanosheet layer is formed by assembling the nanosheets.

  Thereby, the coat particle which laminated | stacked the laminated film which consists of the said resin layer and the said nanosheet layer around the said template particle | grain can be obtained. Furthermore, the laminated film of the resin layer and the nanosheet layer can be further overlapped by alternately and repeatedly immersing the resin such as PEI in the solution and mixing with the sol in which the nanosheet is dispersed. . Moreover, the said resin layer can also be removed suitably by heating in a suitable solvent. The template particles in the coated particles can be removed by heating in an aqueous NaOH solution or an aqueous hydrofluoric acid solution as described above. In this case, the hollow portion can be formed instead of the template particle.

Further, since the above template particles such as polystyrene or the like, mixed in the case of having a positive charge in the dispersion medium, first, a sol dispersed nanosheets composed of _{Ti 2-x Me x O 4} , and the template particles Then, the coated particles in which the nanosheet layer is formed can be obtained by assembling the negatively charged nanosheets around the positively charged template particles.

  Next, the coated particles are immersed in a solution of a resin such as PEI, and the resin layer having a positive charge is formed on the surface of the nanosheet layer having a negative charge in the dispersion medium. The nanosheet layer can be further laminated on the resin layer by mixing the coated particles having the resin layer with the sol in which the nanosheet is dispersed again. Furthermore, by repeating the operation of forming the resin layer and the operation of forming the nanosheet layer, coated particles in which a plurality of the nanosheet layers are stacked around the template particles can be obtained. The template particles in the coated particles can be extracted and removed with an organic solvent such as tetrahydrofuran (THF) as described above. In this case, coated particles in which the hollow portion is formed instead of the template particle can be obtained.

Moreover, it is preferable that the resin layer which consists of a cationic polymer electrolyte is formed between the said nanosheet layers (Claim 8 ).
In this case, as described above, it becomes easy to laminate a plurality of the nanosheets around the template particles.
Moreover, the said resin layer can be removed suitably by heating etc., for example.

Example 1
Next, the coated particles according to the example of the present invention will be described with reference to FIGS.
As shown in FIG. 1 and FIG. 2, in the coated particle 1 of this example, a plurality of nanosheet layers 15 composed of monomolecular nanosheets 151 are laminated around a template particle 11 having a diameter of 0.01 μm to 10 μm. . In this example, the nanosheet 151 is made of Ti _1.6 Ni _0.4 O ₄ .

In the coated particle 1 of this example, a resin layer 13 is formed between the nanosheet layer 15 and the template particle 11. The resin layer 13 is made of polyethyleneimine (PEI). In this example, the template particle 11 is made of silica (SiO ₂ ).

The nanosheet layer 15 is formed by agglomerating nanosheets 151 having a flaky shape and a width of about 5 to 500 nm around the template particles 11. The nanosheets 151 are arranged around the template particle 11 so as to hardly overlap each other and with almost no gap, thereby forming the nanosheet layer 15.
In addition, a total of ten nanosheet layers 15 are laminated around the template particles 11, and a resin layer 13 made of PEI is formed between the nanosheet layers 15.

Next, the method for producing the coated particles of this example will be described.
First, cesium carbonate (Cs ₂ CO ₃ ), titanium dioxide (TiO ₂ ), and nickel oxide (NiO) are mixed at a molar ratio of Cs: Ti: Ni = 0.75: 1.6: 0.4, and the atmosphere It was fired at a temperature of 800 ° C. for 20 hours. Then, to synthesize a powder of Cs _0.75 Ti _1.6 Ni _0.4 O ₄ was quenched to room temperature. An acid treatment was performed by adding 1000 ml of 0.1N aqueous hydrochloric acid to 1 g of this powder. In this acid treatment, the operation of replacing a new hydrochloric acid aqueous solution every day was repeated three times.

Thereafter, the solid phase was filtered, washed with water, and then air-dried to obtain a powder made of Ni-substituted layered titanic acid (H _0.75 Ti _1.6 Ni _0.4 O ₄ .H ₂ O). 0.5 g of this powder was added to 100 ml of an aqueous tetrabutylammonium hydroxide solution and stirred at room temperature at a rotation speed of 150 rpm for about one week to obtain a gray Ni-substituted titania sol. In the sol, nanosheets made of Ti _1.6 Ni _0.4 O ₄ and having a width of about 10 nm to 200 nm are dispersed.
Next, this sol was diluted 50 times with water and the pH was adjusted to 9 to obtain a nanosheet sol.
Further, a polyethyleneimine (PEI) aqueous solution (pH 9) having a concentration of 2 wt% was prepared.

Next, as shown in FIG. 3, template particles 11 having a diameter of 280 nm were prepared. The template particle 11 is made of SiO ₂ and has a negative charge.
Next, 1 g of this template particle was mixed with 150 ml of the PEI aqueous solution prepared above, dispersed in an ultrasonic bath for 10 minutes, and further stirred for 15 minutes. Then, centrifugation for 10 minutes was performed 3 times at 4000 rpm, and the template particle | grains which formed the resin layer which consists of PEI on the surface were collect | recovered.

  Next, the template particles on which this resin layer was formed were mixed with 150 ml of distilled water, dispersed in an ultrasonic bath for 10 minutes, and further stirred for 15 minutes. Thereafter, 5 ml of the nanosheet sol prepared above was added and stirred again for 15 minutes. Subsequently, centrifugation for 10 minutes at 4000 rpm was performed three times, and the coated particles 1 in which the nanosheet layer 15 was laminated on the template particles 11 were collected as shown in FIG. In the coated particle 1, a resin layer 13 is formed between the nanosheet layer 15 and the template particle 11.

  Further, the coated particles were mixed with a PEI aqueous solution in the same manner as described above, dispersed in an ultrasonic bath, stirred, and centrifuged to form a resin layer on the surface of the nanosheet layer. Thereafter, the mixture was mixed with distilled water in the same manner as described above, dispersed in an ultrasonic bath for 10 minutes and stirred for 15 minutes, and then 5 ml of nanosheet sol was added and stirred again for 15 minutes. Centrifugation was performed 3 times at a rotation speed of 4000 rpm for 10 minutes, and the coated particles in which two nanosheet layers were laminated on the template particles were collected. Furthermore, the resin layer and the nanosheet layer were laminated | stacked alternately, and as shown in FIG. 1, the coated particle 1 with which the nanosheet layer 15 was laminated | stacked 10 layers was produced. A resin layer 13 made of PEI is formed between the nanosheet layers 15. In FIG. 1, a diagram in which the number of layers is omitted is shown for the convenience of drawing.

Next, the X-ray diffraction pattern of the coated particles obtained in this example was measured. The result is shown in FIG. In addition, ultraviolet and visible light absorption spectra were measured. The result is shown in FIG.
As can be seen from FIG. 4, the coated particles of this example showed a peak in the vicinity of 2θ = 4.0 in the X-ray diffraction pattern. From this, it can be seen that in the coated particles of this example, the nanosheet layers are laminated in layers at intervals of 2.5 nm.

Further, as can be seen from FIG. 5, the coated particles of this example show a peak having a maximum at 251 nm in the measurement of the ultraviolet / visible light absorption spectrum, and this peak is due to the nanosheet.
From the results of FIG. 4 and FIG. 5, it can be seen that in the coated particles of this example, nanosheet layers are formed around the template particles at a constant interval of 2.5 nm.

As shown in FIG. 1 and FIG. 2, in the coated particle 1 of this example, a nanosheet layer 15 formed by aggregating nanosheets 151 is laminated around the template particle 11, and this nanosheet is composed of Ti _1.6 Ni _0.4 O. _It consists of _four .
Therefore, the coated particle 1 has an absorption wavelength derived from Ni in the composition of the nanosheet 151. The nanosheet layer 15 exhibits highly efficient absorption in a wavelength region of 300 nm or less, and the coated particle 1 can also absorb ultraviolet light in a wide region of 300 nm or less.
Thus, according to this example, coated particles capable of absorbing ultraviolet light in a wide range can be provided.

  The coated particles 1 of this example are formed by aggregating nanosheets 151 made of a single molecular layer around very small template particles 11 having a diameter of 270 nm. Therefore, the coated particles 1 can play a role as colloidal particles. The coated particles 1 can be colored by an interference effect by appropriately controlling the diameter of the template particles 11 and the number of stacked nanosheet layers 15. Therefore, it can be used as, for example, various colorants and paints.

(Example 2)
In this example, coated particles having a nanosheet layer made of Ti _1.6 Co _0.4 O ₄ around template particles are produced.
First, cesium carbonate (Cs ₂ CO ₃ ), titanium dioxide (TiO ₂ ), and cobalt oxide (CoO) are mixed at a molar ratio of Cs: Ti: Co = 0.75: 1.6: 0.4, and the atmosphere It was fired at a temperature of 800 ° C. for 20 hours. Thereafter, the powder was rapidly cooled to room temperature to synthesize a powder composed of Cs _0.75 Ti _1.6 Co _0.4 O ₄ . Next, in the same manner as in Example 1, acid treatment was performed, the solid phase was washed with water and air-dried, and the obtained powder was added to an aqueous solution of tetrabutylammonium hydroxide to obtain a dark blue Co-substituted titania sol. In the sol, nanosheets made of Ti _1.6 Co _0.4 O ₄ and having a width of about 10 nm to 200 nm are dispersed.

  Next, in the same manner as in Example 1, the sol obtained as described above was diluted 50-fold with water, the pH was adjusted to 9, and a nanosheet sol was prepared. A PEI aqueous solution having a concentration of 2 wt% (PH 9) was prepared.

Furthermore, template particles similar to those in Example 1 were prepared, and these template particles were alternately mixed with the PEI aqueous solution and the nanosheet sol in the same manner as in Example 1, and 10 nanosheet layers were laminated on the template particles. Was made.
In the coated particles of this example, the nanosheet layer is made of Ti _1.6 Co _0.4 O ₄ , and other configurations are the same as those in Example 1.

Next, the X-ray diffraction pattern of the coated particles obtained in this example was measured. The result is shown in FIG. In addition, ultraviolet and visible light absorption spectra were measured. The result is shown in FIG.
As can be seen from FIG. 6, the coated particles of this example showed a peak in the vicinity of 2θ = 4.0 in the X-ray diffraction pattern. From this, it can be seen that in the coated particles of this example, the nanosheet layers are laminated in layers at intervals of 2.5 nm.
Further, as can be seen from FIG. 7, the coated particles of this example show a peak having a maximum at 260 nm in the measurement of the ultraviolet / visible light absorption spectrum, and this peak is due to the nanosheet.
From the results of FIG. 6 and FIG. 7, it can be seen that in the coated particles of this example, nanosheet layers are formed around the template particles at a constant interval of 2.5 nm.

(Example 3)
In this example, as shown in FIG. 8, coated particles 2 having a nanosheet layer 25 made of Ti _1.6 Cu _0.4 O ₄ around template particles 21 made of polymethyl methacrylate (PMMA) are produced. Moreover, in this example, as shown in FIG. 9, the coated particle 3 in which the nanosheet layer 35 made of Ti _1.6 Cu _0.4 O ₄ is laminated around the hollow portion 31 is produced.

First, cesium carbonate (Cs ₂ CO ₃ ), titanium dioxide (TiO ₂ ), and copper oxide (CuO) are mixed at a molar ratio of Cs: Ti: Cu = 0.75: 1.6: 0.4, and the atmosphere It was fired at a temperature of 800 ° C. for 20 hours. Then, to synthesize a powder of Cs _0.75 Ti _1.6 Cu _0.4 O ₄ and quenched to room temperature. Next, acid treatment was carried out in the same manner as in Example 1. In this example, the acid treatment was performed by repeating the operation of replacing a new hydrochloric acid aqueous solution every day 10 times.
Thereafter, in the same manner as in Example 1, the solid phase was washed with filtered water and air-dried, and the obtained powder was added to a tetrabutylammonium hydroxide aqueous solution to obtain a yellow Cu-substituted titania sol. In the sol, nanosheets made of Ti _1.6 Cu _0.4 O ₄ and having a width of about 10 nm to 200 nm are dispersed.

  Next, in the same manner as in Example 1, the sol obtained as described above was diluted 50-fold with water, the pH was adjusted to 9 to prepare a nanosheet sol, and a 2 wt% PEI aqueous solution ( pH 9) was prepared.

Next, a template powder made of PMMA and having a diameter of 300 nm was prepared. In the same manner as in Example 1, the template particles were alternately mixed into the PEI aqueous solution and the nanosheet sol, and as shown in FIG. 8, coated particles in which ten nanosheet layers 25 were laminated around the template particles 21 were produced. . A resin layer 23 made of PEI is formed between the template particle 21 and the nanosheet layer 25 and between each nanosheet layer 25 as in the first embodiment.
In the coated particles of this example, the template particles 21 are made of PMMA, the nanosheet layer 25 is made of Ti _1.6 Cu _0.4 O ₄ , and other configurations are the same as those in the first embodiment.

Next, in this example, the template particles 21 are extracted and removed from the coated particles 2 obtained as described above, and the coated particles 3 having the hollow portions 31 are produced as shown in FIG.
Specifically, first, the coated particles 2 (0.1 g) obtained as described above were dispersed in 100 ml of a 0.1 wt% tetrahydrofuran aqueous solution. Subsequently, it stirred for 24 hours at the rotation speed of 50 rpm. As a result, the template particles 21 made of PMMA are extracted and removed, and a hollow portion 31 is formed as shown in FIG. As a result, coated particles 3 were obtained in which the nanosheet layer 35 formed by collecting nanosheets was laminated around the hollow portion 31.

Next, the ultraviolet / visible light absorption spectrum of the coated particles having a hollow part obtained in this example was measured. The result is shown in FIG.
As can be seen from FIG. 10, the coated particles of this example showed a peak having a maximum at 270 nm in the measurement of the ultraviolet / visible light absorption spectrum. This peak is due to the nanosheet.

(Comparative example)
In this example, as shown in FIG. 11, coated particles 9 having nanosheet layers 95 made of Ti _1.8 O ₄ around template particles 91 are produced.
First, cesium carbonate (CsCO ₃ ) and titanium dioxide (TiO ₂ ) were mixed at a molar ratio of Cs: Ti = 0.7: 1.8 and baked in the atmosphere at a temperature of 800 ° C. for 20 hours. Then, to synthesize a powder of Cs _0.7 Ti _1.8 O ₄ was quenched to room temperature. An acid treatment was performed by adding 1000 ml of 0.1N aqueous hydrochloric acid to 1 g of this powder. In the acid treatment, the operation of replacing a new hydrochloric acid aqueous solution every day was repeated 10 times.

Thereafter, the solid phase was filtered, washed with water, and then air-dried to obtain a powder composed of layered titanic acid (H _0.7 Ti _1.8 O ₄ .H ₂ O). 0.5 g of this powder was added to 100 ml of an aqueous tetrabutylammonium hydroxide solution and stirred at room temperature for about 1 week at 150 rpm to obtain a white titania sol. In the sol, nanosheets made of Ti _1.8 O ₄ are dispersed.
Next, the sol obtained as described above was diluted 50 times with water, and the pH was adjusted to 9, which was used as a nanosheet sol.
A 2 wt% PEI aqueous solution (pH 9) was prepared.

Next, a template powder made of PMMA and having a diameter of 300 nm was prepared. In the same manner as in Example 1, the template particles were alternately mixed into the PEI aqueous solution and the nanosheet sol, thereby producing coated particles 9 in which ten nanosheet layers 95 were laminated as shown in FIG. In FIG. 11, the number of stacked nanosheet layers is omitted for the convenience of drawing. Further, a resin layer 93 made of PEI is formed between the template particle 91 and the nanosheet layer 95 and between each nanosheet layer 95 as in the first embodiment.
In the coated particles 9 of this example, the template particles 91 are made of PMMA, and the nanosheet layer 95 is made of Ti _1.8 O ₄ .

  Next, an ultraviolet / visible light absorption spectrum of the coated particle 9 obtained in this example was measured. As a result, the coated particle 9 of this example showed a peak having a maximum at 265 nm. Accordingly, the coated particles 9 of this example absorb the wavelength of 265 nm with high efficiency. However, the coated particles 9 of this example have low absorption efficiency in other wavelength regions, and could not sufficiently absorb ultraviolet rays.

According to Example 1, cross-sectional view of a coated particle having a nanosheet layer around the template particles composed of SiO _2. The elements on larger scale which show the structure of the nanosheet layer in the coated particle concerning Example 1. FIG. FIG. 3 is an explanatory diagram showing template particles made of silica according to Example 1. The figure which shows the X-ray-diffraction pattern of the coated particle concerning Example 1. FIG. The figure which shows the ultraviolet and visible light absorption spectrum of the coated particle concerning Example 1. FIG. The figure which shows the X-ray-diffraction pattern of the coated particle concerning Example 2. FIG. The figure which shows the ultraviolet and visible light absorption spectrum of the coated particle concerning Example 2. FIG. Sectional explanatory drawing of the coated particle which has a nanosheet layer around the template particle which consists of PMMA concerning Example 3. FIG. Sectional explanatory drawing of the coated particle which has a nano sheet layer around the hollow part concerning Example 3. FIG. The figure which shows the ultraviolet and visible light absorption spectrum of the coating particle which has a nanosheet layer around the hollow part concerning Example 3 According to the comparative example, explanatory view showing a coated particle having a nanosheet consisting Ti _1.8 O ₄ around the coated particles.

Explanation of symbols

1 Coat particle 11 Template particle 13 Resin layer 15 Nanosheet layer

Claims (8)

Around the template particles with a diameter of 0.01 to 10 m, the nanosheet layer made of Na Noshito is a coated particle that are stacked one or more layers,
The _{nanosheet, Ti 2-x Me x O} 4 (Me is Ni, Co, Cu, Zn, and one or more selected from Fe, x is 0.4 or 0.8) Tona is,
Coated particles, wherein a resin layer made of a cationic polymer electrolyte is formed between the nanosheet layer and the template particles. 2. The coated particle according to claim 1, wherein the template particle is made of silica . 3. The coated particle according to claim 1, wherein the template particle is made of polymethyl methacrylate or polystyrene . Coated particles in which one or more nanosheet layers made of monomolecular nanosheets are laminated around a hollow portion having a diameter of 0.01 μm to 10 μm,
The _{nanosheet, Ti 2-x Me x O} 4 (Me is Ni, Co, Cu, Zn, and one or more selected from Fe, x is 0.4 or 0.8), characterized in that it consists of coating particle. 5. The coated particle according to claim 4, wherein a resin layer made of a cationic polymer electrolyte is formed between the nanosheet layer and the hollow portion . The coated particle according to any one of claims 1 to 5, wherein the nanosheet layer is configured by combining the nanosheets having a width of 5 nm to 500 nm. The coated particle according to any one of claims 1 to 6, wherein a plurality of the nanosheet layers are laminated . The coated particle according to claim 7, wherein a resin layer made of a cationic polymer electrolyte is formed between the nanosheet layers .

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