JP2013136663A - Weather-resistant particle, weather-resistant particle-containing dispersion liquid, weather-resistant particle-containing resin composition, and weather-resistant film and weather-resistant substrate using the same resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weather-resistant particles that are excellent in transparency and UV shielding properties and have excellent long-term weatherability, to provide a weather-resistant particle-containing dispersion liquid, to provide a weather-resistant particle-containing resin composition and to provide a weather-resistant film and a weather-resistant substrate that use the resin composition.SOLUTION: The weather-resistant particle 1 has a first coating layer 3 composed of silicon oxide in an amount of not less than 5 vol% and not more than 60 vol% based on the volume of the UV shielding particle 2, formed on the surface of a UV shielding particle 2 having an average primary particle size of not less than 5 nm and not more than 100 nm, and have a second coating layer 4 composed of a silicone resin in an amount of not less than 15 vol% and not more than 300 vol% based on the volume of the UV shielding particle 2, formed on the surface of the first coating layer 3, and has an average particle size of not less than 6 nm and not more than 200 nm.

Description

  The present invention relates to a weather-resistant particle, a weather-resistant particle-containing dispersion, a weather-resistant particle-containing resin composition, a weather-resistant film and a weather-resistant substrate using the same, and more specifically, it is transparent and excellent in ultraviolet shielding properties, and Weather-resistant particles suitable for use in base materials used outdoors where long-term weather resistance is required, a weather-resistant particle-containing dispersion in which the weather-resistant particles are dispersed in a solvent, and the weather-resistant particles and resin And a weather-resistant film and a weather-resistant substrate formed using this weather-resistant particle-containing resin composition.

In order to prevent deterioration caused by sunlight, especially deterioration caused by ultraviolet rays contained in sunlight, components exposed to sunlight, especially outdoor base materials that continue to be exposed to sunlight during the day, are not sensitive to sunlight, especially ultraviolet rays. Weather resistance is required. Therefore, it is necessary to form a film for imparting weather resistance to sunlight, particularly ultraviolet rays, on the surface of the member, particularly the surface of an outdoor base material.
Examples of the ultraviolet shielding agent for forming a film having such weather resistance include an ultraviolet shielding agent using inorganic ultraviolet shielding particles, an organic ultraviolet absorber and a light stabilizer for a specific radical polymerizable compound. A coating composition to which is added has been proposed (Patent Document 1).

JP 2003-238845 A

However, in the coating composition as described in Patent Document 1 described above, an organic ultraviolet absorber is used as the ultraviolet shielding agent, so that the organic ultraviolet absorber was exposed outdoors for a long time. In this case, the organic ultraviolet absorber is deteriorated by exposure to ultraviolet rays, and as a result, the coating film using the organic ultraviolet absorber is deteriorated, and the long-term weather resistance is insufficient. was there.
On the other hand, the ultraviolet ray shielding agent using inorganic ultraviolet ray shielding particles has insufficient transparency and ultraviolet ray shielding properties, and also has insufficient suppression of the photoactivity of the particles, so that long-term weather resistance is obtained. There was a problem that it was not possible.

  The present invention has been made in view of the above circumstances, and is excellent in transparency and ultraviolet shielding properties, and has excellent weather resistance, long-term weather resistance, a weather-resistant particle-containing dispersion, and a weather-resistant particle-containing resin. An object is to provide a composition and a weather-resistant film and a weather-resistant substrate using the composition.

  As a result of intensive studies in order to solve the above problems, the present inventors have made a first coating layer made of a predetermined amount of silicon oxide on the surface of ultraviolet shielding particles having an average primary particle diameter of 5 nm or more and 100 nm or less. In addition, the second coating layer made of a predetermined amount of silicon resin is sequentially coated to obtain particles having an average particle diameter of 6 nm or more and 200 nm or less, thereby providing excellent transparency and ultraviolet shielding properties and long-term weather resistance. The inventors have found that excellent weather-resistant particles can be obtained, and have completed the present invention.

  That is, the weather resistant particle of the present invention is composed of a silicon oxide having an average primary particle diameter of 5 nm or more and 100 nm or less on the surface of the silicon oxide having 5% by volume or more and 60% by volume or less with respect to the UV shielding particle. 1 coating layer is formed, and on the surface of the first coating layer, a second coating layer made of a silicon resin of 15 volume% or more and 300 volume% or less with respect to the volume of the ultraviolet shielding particles is formed, The average particle diameter is 6 nm or more and 200 nm or less.

In the weather resistant particle of the present invention, it is preferable that a surface treatment layer mainly composed of aluminum hydroxide is formed on the surface of the ultraviolet shielding particle.
It is preferable that a third coating layer made of a metal compound is formed between the first coating layer and the second coating layer.

  The weather resistant particle-containing dispersion of the present invention is characterized in that the weather resistant particles of the present invention are dispersed in a solvent.

  The weather resistant particle-containing resin composition of the present invention comprises the weather resistant particle of the present invention and a resin.

  The weather resistant film of the present invention is formed by the weather resistant particle-containing resin composition of the present invention.

  The weather resistant substrate of the present invention comprises the weather resistant film of the present invention.

  According to the weather resistant particle of the present invention, the surface of the ultraviolet shielding particle having an average primary particle diameter of 5 nm or more and 100 nm or less is composed of 5% by volume or more and 60% by volume or less of silicon oxide with respect to the ultraviolet shielding particle. 1 coating layer is formed, and a second coating layer made of silicon resin of 15 volume% or more and 300 volume% or less with respect to the volume of the ultraviolet shielding particles is formed on the surface of the first coating layer. Since the average particle diameter is 6 nm or more and 200 nm or less, the ultraviolet shielding ability can be maintained over a long period of time, and there is no possibility of deterioration. Therefore, transparency and ultraviolet shielding properties can be maintained over a long period of time, and excellent long-term weather resistance can be achieved.

  According to the weatherable particle-containing dispersion of the present invention, since the weatherable particles of the present invention are dispersed in a solvent, the ultraviolet shielding ability can be maintained over a long period of time. Therefore, weather resistance can be maintained over a long period of time.

  According to the weather resistant particle-containing resin composition of the present invention, since the weather resistant particle of the present invention and the resin are contained, the ultraviolet shielding ability can be maintained over a long period of time. Therefore, weather resistance can be maintained over a long period of time.

  According to the weather resistant film of the present invention, since it is formed by the weather resistant particle-containing resin composition of the present invention, the transparency and ultraviolet shielding property of the film can be maintained over a long period of time. Therefore, it is possible to provide a film having excellent transparency and ultraviolet shielding properties and excellent long-term weather resistance.

  According to the weather resistant substrate of the present invention, since the weather resistant film of the present invention is provided, the transparency and ultraviolet shielding property on the surface of the weather resistant substrate can be maintained over a long period of time. Therefore, it is possible to provide a weather-resistant substrate that is excellent in transparency and ultraviolet shielding properties and excellent in long-term weather resistance.

It is sectional drawing which shows the weather-resistant particle | grains of the 1st Embodiment of this invention. It is sectional drawing which shows the weather-resistant particle | grains of the 2nd Embodiment of this invention. It is a figure which shows the result of having measured the visible light transmittance | permeability of the weather-resistant particle | grains of Example 1 of this invention.

The form for implementing the weather resistant particle | grains of this invention, a weather resistant particle containing dispersion liquid, a weather resistant particle containing resin composition, and a weather resistant film | membrane and a weather resistant base material using the same is demonstrated.
The following embodiments are specifically described for better understanding of the gist of the invention, and do not limit the present invention unless otherwise specified.

[First Embodiment]
FIG. 1 is a cross-sectional view showing a weather-resistant particle according to the first embodiment of the present invention. This weather-resistant particle 1 is formed on the surface of an ultraviolet shielding particle 2 having an average primary particle diameter of 5 nm or more and 100 nm or less. A first coating layer 3 made of silicon oxide at 5 volume% or more and 60 volume% with respect to the ultraviolet shielding particles 2 is formed, and the surface of the first coating layer 3 is formed with respect to the volume of the ultraviolet shielding particles 2. A second coating layer 4 made of silicon resin of 15 volume% or more and 300 volume% or less is formed.

"Weather-resistant particles"
The average particle diameter of the weather resistant particles 1 is 6 nm or more and 200 nm or less, preferably 6 nm or more and 150 nm or less, more preferably 10 nm or more and 100 nm or less, and further preferably 10 nm or more and 50 nm or less.
Here, the reason why the above range is preferable for the average particle diameter of the weather-resistant particles 1 is that when the average particle diameter is less than 6 nm, the surface activity increases as the particle diameter decreases, and as a result, the particles easily aggregate. This is because the dispersibility may be deteriorated, and it is not preferable because it is difficult to manufacture and difficult to handle in the process. On the other hand, if the average particle diameter exceeds 200 nm, the weather-resistant particles are not preferable. This is because when the film is formed using 1, the transparency of the obtained film may be deteriorated, which is not preferable.

  The average particle diameter of the weather-resistant particles 1 and the average primary particle diameter of the ultraviolet shielding particles 2 are none from a transmission electron microscope image (TEM image) obtained by observing these particles with a transmission electron microscope. It can be obtained by selecting a predetermined number, for example, 100 or 500 particles for measurement, measuring the particle diameter of each particle, and calculating an average value from these measured values.

Next, the weather resistant particles will be described in detail.
(UV shielding particles)
The ultraviolet shielding particle 2 is not particularly limited as long as it is a metal oxide particle capable of shielding light in the ultraviolet region, and examples thereof include titanium oxide, zinc oxide, cerium oxide, tungsten oxide, and strontium titanate. 1 type (s) or 2 or more types selected from a group can be used.

  For example, as titanium oxide, titanium oxide particles composed of any one of rutile type and anatase type, or titanium oxide particles in a mixed crystal state of rutile type and anatase type can be used. Among these, rutile type titanium oxide is preferable in that photoactivity can be further suppressed.

  The average primary particle diameter of the ultraviolet shielding particles 2 is preferably 5 nm or more and 100 nm or less, more preferably 5 nm or more and 50 nm or less, and further preferably 10 nm or more and 30 nm or less. Here, when the average primary particle diameter is less than 5 nm, the specific surface area increases, so that the photoactivity on the surface may be increased, and further, the production is difficult and the handling is difficult. On the other hand, if the average primary particle diameter exceeds 50 nm, the transparency of the ultraviolet shielding particles 2 itself to visible light may be lowered, which is not preferable.

(First coating layer)
The first coating layer 3 is formed on the surface of the ultraviolet shielding particles 2 and is a coating layer made of silicon oxide.
The coating amount of the silicon oxide may be appropriately adjusted, but is preferably 5% by volume or more and 60% by volume or less, more preferably 10% by volume or more and 50% by volume or less, with respect to the ultraviolet shielding particles 2 described above. Preferably they are 30 volume% or more and 40 volume% or less.

  Here, if the coating amount of silicon oxide is less than 5% by volume, the effect of suppressing the photoactivity of the ultraviolet shielding particles 2 may be insufficient, and on the other hand, if the coating amount exceeds 60% by volume, Even if the coating amount is increased further, the effect of suppressing the photoactivity of the ultraviolet shielding particles 2 is saturated, the silicon oxide is wasted by the increased coating amount, and further, in order to obtain a predetermined ultraviolet shielding property. Since the amount of particles added is relatively increased and as a result, the transparency is adversely affected, it is not preferable.

For example, when the first coating layer 3 made of silicon oxide of 5 volume% or more and 60 volume% or less is formed on the surface of the ultraviolet shielding particle 2 having a primary particle diameter of 20 nm, the first coating layer 3 The thickness is theoretically about 0.3 nm to 3.5 nm.
The first coating layer 3 is preferably uniformly coated on the surface of the ultraviolet shielding particles 2, but may be partially coated to such an extent that desired weather resistance is obtained.

(Second coating layer)
The second coating layer 4 is a coating layer formed on the surface of the first coating layer 3 and is a coating layer made of silicon resin (silicone).
The coating amount of the silicone resin is preferably 15% by volume or more and 300% by volume or less, more preferably 40% by volume or more and 250% by volume or less, more preferably 100% by volume with respect to the volume of the ultraviolet shielding particles 2 described above. % To 220% by volume.

  Here, if the coating amount of the silicon resin is less than 15% by volume, the effect of suppressing the photoactivity of the ultraviolet shielding particles 2 may be insufficient. On the other hand, if the coating amount exceeds 300% by volume, the coating is more than this. Even if the amount is increased, the effect of suppressing the photoactivity of the ultraviolet shielding particles 2 is saturated, and the silicon resin is easily released into other components. If produced, the properties of the weather-resistant film may be adversely affected. Furthermore, the amount of particles added is relatively increased to obtain a predetermined ultraviolet shielding property, resulting in a decrease in transparency. It is not preferable because it has an adverse effect.

By making this 2nd coating layer 4 into the outermost layer, the compatibility of this weather-resistant particle | grains 1 and the resin mentioned later improves, and the weather-resistant particle | grains which were excellent in transparency can be obtained.
In addition, when the primary particle diameter of the ultraviolet shielding particles 2 on which the first coating layer 3 is formed is 20 nm, the surface of the first coating layer 3 is made of a silicon resin of 15 volume% or more and 300 volume% or less. When the second coating layer 4 is formed, the thickness of the second coating layer 4 is theoretically about 0.5 nm to 11 nm. The second coating layer 4 is preferably uniformly coated on the particles, but may be partially coated to such an extent that desired weather resistance can be obtained.

(Third coating layer)
In order to further suppress the photoactivity of the ultraviolet shielding particles 2, one or more third coating layers made of a metal compound are formed between the first coating layer 3 and the second coating layer 4. It is good to do.
Although it does not specifically limit as a metal compound, The substance which is hard to be decomposed | disassembled by the photoactivity of titanium oxide is preferable, for example, selected from the group of oxides, hydroxides, hydrates, etc., such as aluminum, silicon, and zirconium. 1 type or 2 types or more are preferable.

The coating amount of the third coating layer may be appropriately adjusted, but is preferably 1% by volume or more and 50% by volume or less, more preferably 10% by volume or more and 30% by volume or less with respect to the ultraviolet shielding particles 2.
When the third coating layer covers the first coating layer 3 within the above range, the photoactivity of the ultraviolet shielding particles 2 is further suppressed, and the transparency is not adversely affected.

  In addition, when this 3rd coating layer is coat | covered with the coating amount of 1 volume% or more and 50 volume% or less with respect to the ultraviolet shielding particle 2 with a particle diameter of 20 nm, the thickness of this 3rd coating layer is theoretically. It is about 0.05 nm to 2.2 nm. The third coating layer is preferably uniformly coated on the particles, but may be partially coated to the extent that desired weather resistance can be obtained.

Although the detailed mechanism about which the weather resistance particle | grains 1 of this embodiment can obtain the outstanding weather resistance is unknown, it estimates as follows.
That is, the ultraviolet shielding particles 2 are confined inside by covering the surface of the ultraviolet shielding particles 2 with the first coating layer 3 made of silicon oxide and the second coating layer 4 made of silicon resin. It is presumed that particles can be prevented from floating on the surface of a coating film or the like described later.

"Method for producing weather-resistant particles"
In the method for producing weatherable particles according to the present embodiment, a silicon alkoxide such as tetraalkoxysilane is reacted in a solvent in the presence of water, whereby the surface of the ultraviolet shielding particles 2 is made of silicon oxide. The second coating step of forming a second coating layer 4 made of a silicone resin on the first coating layer 3 by further adding a silicone resin to react with the first coating step And have.
In addition, when forming the 3rd coating layer which consists of a metal compound between the 1st coating layer 3 and the 2nd coating layer 4, a 3rd coating layer is attached after a 1st coating process. A third covering step to be formed may be performed, and then a second covering step may be performed.

Next, the manufacturing method of this weather-resistant particle | grain is demonstrated in detail.
(First covering step)
In this step, the ultraviolet shielding particles and tetraalkoxysilane are reacted in a solvent in the presence of water to disperse the ultraviolet shielding particles in the solvent, and the first oxide consisting of silicon oxide on the surface of the ultraviolet shielding particles. The coating layer is simultaneously formed.

The tetraalkoxysilane is not particularly limited as long as the first coating layer 3 made of silicon oxide can be formed on the surface of the ultraviolet shielding particles. For example, tetraethoxysilane, tetramethoxysilane, tetraisopropoxysilane, One or more selected from the group of tetrabutoxysilane can be used.
An appropriate amount of ammonia, sodium hydroxide, sulfuric acid, hydrochloric acid, nitric acid, or the like may be added to the solution containing ultraviolet shielding particles and tetraalkoxysilane in order to increase the hydrolysis rate of this tetraalkoxysilane and increase production efficiency. . Moreover, you may mix an organic solvent with said solution as needed.

  As an apparatus used in the first coating step, a known mixing apparatus or dispersing apparatus can be used. Examples of these devices include a ball mill, a roll mill, a bead mill, a homogenizer, an ultrasonic device, a pin mill, a planetary ball mill, a jet mill, a vibration mill, a pearl mill, a dyno mill, an ultra visco mill, an attritor, and an annular mill.

(Second covering step)
In this step, the silicone resin is added to the ultraviolet shielding particles obtained in the first coating step and the first coating layer is formed on the surface, and reacted to thereby form silicon on the first coating layer. A second coating layer made of resin is formed.

The silicone resin is not particularly limited, but a silicone resin containing an alkoxy group is preferred, and a methyl silicone resin or a methylphenyl silicone resin containing an alkoxy group is preferred.
Moreover, as an alkoxy group, a methoxy group or an ethoxy group is preferable at the point which is rich in reactivity.

Moreover, you may use a silane coupling agent instead of this silicone resin.
As this silane coupling agent, as in the case of the silicone resin, a silane coupling agent having an alkoxy group is preferable, and the alkoxy group is more preferably a methoxy group or an ethoxy group in terms of rich reactivity.

The reason why the silicone resin containing this alkoxy group is preferable is presumed to be as follows.
The silicone resin containing an alkoxy group is coated on the surface of the particle, that is, the surface of the first coating layer formed on the surface of the ultraviolet shielding particle by a covalent bond by hydrolysis of the alkoxy group. Furthermore, since the resins coated on the surface of the first coating layer also react to form a skeleton, the surface of the first coating layer is more firmly coated with silicone.
That is, when the surface of the particles is firmly coated, and when the resin composition described later is produced using the particles coated with the surface, the dispersibility of the particles in the resin composition is improved. It is estimated that the weather resistance can be improved.

  As an apparatus used in the second coating process, for example, a ball mill, a roll mill, a bead mill, a homogenizer, an ultrasonic device, a pin mill, a planetary ball mill, a jet mill, a vibration mill, a pearl mill, and a dyno mill, as in the first coating process. Ultravisco mill, attritor, annula mill, etc. can be used.

  Here, in order to further suppress the photoactivity of the ultraviolet shielding particles, when a third coating layer made of a metal compound is formed between the first coating layer and the second coating layer, The following (third coating step) is provided between (first coating step) and (second coating step).

(Third covering step)
In this step, a metal alkoxide is added to the solution containing the ultraviolet shielding particles having the first coating layer formed on the surface obtained in the first coating step, and the pH is adjusted as necessary to react. Thus, a metal compound is generated from the metal alkoxide, and one or more third coating layers made of the metal compound are formed on the first coating layer.
Examples of the metal alkoxide include aluminum alkoxides such as aluminum tetrapropoxide, zirconium alkoxides such as zirconium tetrapropoxide, and the like.

By each of the above methods, a first coating layer made of silicon oxide and a second coating layer made of silicon resin are sequentially laminated on the surface of the ultraviolet shielding particles 2, or the first coating layer made of silicon oxide. The third coating layer made of a metal compound and the second coating layer made of a silicon resin can be sequentially laminated.
Therefore, it is possible to easily obtain weather-resistant particles having a small particle diameter, excellent transparency, good ultraviolet shielding properties and excellent long-term weather resistance.

`` Dispersion containing weathering particles ''
The weather resistant particle-containing dispersion of the present embodiment is a dispersion formed by dispersing the weather resistant particles of the present embodiment in a solvent.
The solvent may be appropriately selected in consideration of compatibility with the resin used in the weather resistant particle-containing resin composition described later. Examples of such a solvent include water, methanol, ethanol, 1-propanol, 2-propanol (isopropyl alcohol; IPA), propylene glycol monomethyl ether, propylene glycol monopropyl ether, diacetone alcohol, methyl isobutyl ketone, methyl ethyl ketone, and the like. Is mentioned.
Among these, methanol, ethanol, 1-propanol and 2-propanol are preferable, and 2-propanol is particularly preferable.

The average dispersed particle size of the weather resistant particles in this weather resistant particle-containing dispersion is preferably 6 nm or more and 200 nm or less. In addition, it is difficult to produce particles having an average dispersed particle diameter of less than 6 nm. On the other hand, particles having an average dispersed particle diameter exceeding 200 nm are not preferable because transparency may be lowered.
The average dispersed particle diameter in the present embodiment is an average volume dispersed particle diameter (d50) measured by a dynamic light scattering method.

  In this weather-resistant particle-containing dispersion, generally used additives such as a dispersant, an antifoaming agent, a leveling agent, a lubricant, and an antioxidant may be added as appropriate as long as the characteristics are not lost.

When producing this weather-resistant particle-containing dispersion, the dispersion obtained by the above-mentioned method for producing weather-resistant particles may be used as it is, and the above-mentioned solvent may be added as necessary. In addition, the dispersion obtained by the above-mentioned method for producing weatherable particles is subjected to solvent removal treatment, or the weatherable particles obtained by drying this dispersion are dispersed again in the solvent. You may let them.
Further, the weatherable particle-containing dispersion may be concentrated by drying or the like, or dried to form the weatherable particles in powder form.

"Weather-resistant particle-containing resin composition"
The weather resistant particle-containing resin composition of the present embodiment is a resin composition containing the weather resistant particles of the present embodiment and a resin.
It does not specifically limit as resin, What is necessary is just to select suitably according to the use of this weather-resistant particle | grain containing resin composition. For example, in the case where wear resistance is important, an ultraviolet curable resin excellent in wear resistance is preferable. Examples of such an ultraviolet curable resin include acrylic resins, epoxy resins, silicon resins, phenol resins, polyimide resins, Polybenzoxazole resin, polyphenylene resin, polybenzocyclobutene resin, polyarylene ether resin, polycyclohexane resin, polyester resin, fluororesin, polyolefin resin, polycycloolefin resin, cyanate resin, polyphenylene ether resin, polystyrene resin, polyvinyl butyral resin 1 type, or 2 or more types can be used.
Moreover, when importance is attached to transparency, highly transparent acrylic resin, polycarbonate resin, etc. are preferable.

In order to improve the weather resistance of the weather resistant particle-containing resin composition, it is preferable to add a light stabilizer as appropriate. As such a light stabilizer, a hindered amine light stabilizer having a hindered amine group is preferable.
The weather resistant particle-containing resin composition is generally used as an organic ultraviolet absorber, an antifoaming agent, a leveling agent, a lubricant, an antioxidant, a photoinitiator, a polymerization inhibitor, etc., as long as the characteristics are not lost. The additive to be used may be appropriately added. Moreover, you may add a solvent for the purpose of solid content adjustment and the adjustment of a drying rate. As such a solvent, a solvent having good compatibility with the above-mentioned resin may be selected in consideration of the coating method.

This weather-resistant particle-containing resin composition can be obtained by mixing the weather-resistant particles or the weather-resistant particle-containing dispersion of this embodiment with a resin.
What is necessary is just to adjust the mixing ratio of this weather-resistant particle | grain and resin so that a desired weather resistance and film | membrane intensity | strength may be obtained according to a use.

"Weather-resistant membrane"
The weather resistant film of the present embodiment is a film formed from the weather resistant particle-containing resin composition of the present embodiment.
The film thickness of the weather resistant film may be appropriately adjusted according to the application, but is usually preferably 1 μm or more and 15 μm or less, and more preferably 5 μm or more and 10 μm or less.
Here, when the film thickness is less than 1 μm, the ultraviolet shielding property may not be sufficient, which is not preferable. On the other hand, when the film thickness exceeds 15 μm, in some cases, the transparency is lowered. Since there is a possibility, it is not preferable.

This weather resistant film can be formed by applying the weather resistant particle-containing resin composition of the present embodiment to a substrate and curing it by a curing method according to the type of the resin.
The method for applying the weatherable particle-containing resin composition is not particularly limited. For example, a bar coating method, a flow coating method, a dip coating method, a spin coating method, a roll coating method, a spray coating method, a meniscus coating method, A normal wet coating method such as a suction coating method can be used.

"Weather-resistant substrate"
The weather resistant substrate of the present embodiment includes the weather resistant film of the present embodiment.
This weather resistant substrate can be obtained by applying and curing a paint containing the weather resistant particle-containing resin composition of the present embodiment on a substrate using a known coating method.

The base material is not particularly limited as long as it can be applied with a paint containing the weatherable particle-containing resin composition of the present embodiment, and examples thereof include a plastic base material and a glass base material. Here, as the plastic substrate, for example, acrylic resin, acrylic resin containing highly elastic acrylic rubber, acrylic-styrene copolymer, polystyrene resin, polyethylene resin, polypropylene resin, polycarbonate resin, polyethylene terephthalate, triacetyl cellulose , Acrylonitrile-butadiene-styrene copolymer, vinyl chloride, or the like can be used.
In addition, one type selected from the above group of base materials may be used alone, or two or more types may be laminated and used.

  As described above, according to the weather resistant particles of the present embodiment, the surface of the ultraviolet shielding particles having an average primary particle diameter of 5 nm or more and 100 nm or less is 5 vol% or more and 60 vol% with respect to the ultraviolet shielding particles. Since the first coating layer made of silicon oxide and the second coating layer made of silicon resin of 15 volume% or more and 300 volume% or less with respect to the volume of the ultraviolet shielding particles are sequentially laminated, transparency and ultraviolet shielding properties In addition, it has excellent long-term weather resistance.

Furthermore, when the third coating layer made of a metal compound is formed between the first coating layer and the second coating layer, the photoactivity of the ultraviolet shielding particles is further suppressed, and the particles are stronger. Since it is coated, it has excellent long-term weather resistance.
As described above, the ultraviolet shielding ability can be maintained over a long period of time, there is no possibility of deterioration, the transparency and the ultraviolet shielding ability can be maintained over a long period of time, and excellent in long-term weather resistance. Can be.

  According to the method for producing weatherable particles of this embodiment, a silicon alkoxide such as tetraalkoxysilane is reacted in a solvent in the presence of water, whereby the surface of the ultraviolet shielding particles 2 is made of silicon oxide. A first coating step for forming the coating layer 3 and a second coating layer 4 made of silicon resin are formed on the first coating layer 3 by further adding and reacting a silicone resin. Coating process, so that the UV shielding ability can be maintained over a long period of time, there is no risk of deterioration, transparency and UV shielding ability can be maintained over a long period of time, and long-term weather resistance In addition, excellent weather-resistant particles can be easily produced.

  According to the weather resistant particle-containing dispersion of this embodiment, the weather resistant particles of this embodiment are dispersed in a solvent, so that the ultraviolet shielding ability can be maintained over a long period of time. Therefore, weather resistance can be maintained over a long period of time.

  According to the weather resistant particle-containing resin composition of the present embodiment, since the weather resistant particle and the resin of the present embodiment are contained, the ultraviolet shielding ability can be maintained over a long period of time. Therefore, weather resistance can be maintained over a long period of time.

  According to the weather resistant film of the present embodiment, since it is formed by the weather resistant particle-containing resin composition of the present embodiment, the transparency and ultraviolet shielding property of the film can be maintained over a long period of time. Therefore, it is possible to provide a film having excellent transparency and ultraviolet shielding properties and excellent long-term weather resistance.

  According to the weather resistant substrate of the present embodiment, since the weather resistant film of the present embodiment is provided, the transparency and ultraviolet shielding property on the surface of the weather resistant substrate can be maintained over a long period of time. Therefore, it is possible to provide a weather-resistant substrate that is excellent in transparency and ultraviolet shielding properties and excellent in long-term weather resistance.

[Second Embodiment]
FIG. 2 is a cross-sectional view showing a weather-resistant particle according to the second embodiment of the present invention. This weather-resistant particle 11 is replaced with the ultraviolet shielding particle 2 having an average primary particle diameter of 5 nm or more and 100 nm or less. The first embodiment is that the surface-treated ultraviolet shielding particles 13 in which the surface treatment layer 12 mainly composed of aluminum hydroxide is formed on the surface of the ultraviolet shielding particles 2 having an average primary particle diameter of 5 nm or more and 100 nm or less are used. The first embodiment is that the first coating layer 3 and the second coating layer 4 are sequentially formed on the surface of the surface-treated ultraviolet shielding particles 13. This is exactly the same as the weather-resistant particles 1.

"Weather-resistant particles"
Here, the weather-resistant particles 11 of the present embodiment will be described for differences from the weather-resistant particles 1 of the first embodiment.
In the weather resistant particle 11, the first coating layer 3 and the second coating layer 4 are sequentially formed on the surface of the surface-treated ultraviolet shielding particle 13.

"Surface treatment UV shielding particles"
The surface-treated ultraviolet shielding particles 13 are obtained by surface-treating the surface of the ultraviolet shielding particles 2 with aluminum hydroxide so that a surface treatment layer 12 mainly composed of aluminum hydroxide is formed on the surface.

The coating amount (volume) of the surface treatment layer 12 is preferably 1% by volume or more and 35% by volume or less, more preferably 20% by volume or more and 30% by volume or less of the ultraviolet shielding particles 2.
Here, when the coating amount (volume) of the surface treatment layer 12 is less than 1% by volume of the ultraviolet shielding particles 2, the effect of suppressing the photoactivity of the ultraviolet shielding particles 2 is insufficient, and this is not preferable. In a dispersion or a resin composition in which the surface-treated ultraviolet shielding particles 13 are dispersed in a solvent or a resin, the dispersibility of the surface-treated ultraviolet shielding particles 13 is deteriorated and the transparency is inferior. Because there is, it is not preferable. On the other hand, when the coating amount (volume) of the surface treatment layer 12 exceeds 35 volume% of the ultraviolet shielding particles 2, the effect of suppressing the photoactivity of the ultraviolet shielding particles 2 itself is saturated, and the effect of further suppressing the photoactivity is obtained. In addition, aluminum hydroxide is wasted, and in order to obtain a predetermined ultraviolet shielding property, the amount of the surface-treated ultraviolet shielding particles 13 is relatively increased, which adversely affects the transparency. Since there is a possibility that it may affect, it is not preferable.

The reason why the surface treatment layer 12 made of aluminum hydroxide can improve the transparency of the surface-treated ultraviolet shielding particles 13 itself is considered as follows.
Since aluminum hydroxide easily adsorbs silicon oxide, which is a hydrophilic substance, by forming a surface treatment layer 12 made of aluminum hydroxide on the surface of the ultraviolet shielding particles 2, a first treatment is performed on the surface treatment layer 12. The hydrophilic silicon oxide constituting the coating layer 3 is more easily adsorbed. As described above, the hydrophilic silicon oxide is efficiently adsorbed on the surface of the surface treatment layer 12, thereby suppressing aggregation of the ultraviolet shielding particles 2. As a result, the surface treated ultraviolet shielding particles 13 are contained in the solvent. In the case of the dispersed dispersion or the resin composition dispersed in the resin, it is considered that the dispersion of the surface-treated ultraviolet shielding particles 13 easily proceeds and the transparency is improved.

(First coating layer)
The coating amount of silicon oxide in the first coating layer 3 is preferably 5% by volume or more and 60% by volume or less, more preferably 10% by volume or more and 50% by volume or less with respect to the surface-treated ultraviolet shielding particles 13. Preferably they are 30 volume% or more and 40 volume% or less.

  Here, if the coating amount of silicon oxide is less than 5% by volume, the effect of suppressing the photoactivity of the surface-treated ultraviolet shielding particles 13 may be insufficient. On the other hand, the coating amount exceeds 60% by volume. Even if the coating amount is increased further, the effect of suppressing the photoactivity of the surface-treated ultraviolet shielding particles 13 is saturated, and silicon oxide is wasted by the increased coating amount. In this case, the amount of particles added is relatively increased in order to obtain the desired value, and as a result, the transparency is adversely affected.

  Here, for example, when the first coating layer 3 made of silicon oxide of 5 volume% or more and 60 volume% or less is formed on the surface of the surface-treated ultraviolet shielding particles 13 having an average primary particle diameter of 20 nm, The thickness of one coating layer 3 is theoretically about 0.3 nm to 3.5 nm.

(Second coating layer)
The coating amount of the silicone resin in the second coating layer 4 is preferably 15% by volume or more and 300% by volume or less, more preferably 40% by volume or more and 250% with respect to the volume of the surface-treated ultraviolet shielding particles 13 described above. It is not more than volume%, more preferably not less than 100 volume% and not more than 220 volume%.

  Here, if the coating amount of the silicon resin is less than 15% by volume, the effect of suppressing the photoactivity of the surface-treated ultraviolet shielding particles 13 may be insufficient. On the other hand, if the coating amount exceeds 300% by volume, Even if the coating amount is increased, the effect of suppressing the photoactivity of the surface-treated ultraviolet shielding particles 13 is saturated, and the silicon resin is easily released into other components. When a weather-resistant film is produced, the properties of the weather-resistant film may be adversely affected, and furthermore, the amount of particles added is relatively increased in order to obtain a predetermined ultraviolet shielding property. This is not preferable because it has an adverse effect such as a decrease in the thickness.

(Third coating layer)
In order to further suppress the photoactivity of the surface-treated ultraviolet shielding particles 13, a metal compound is used between the first coating layer 3 and the second coating layer 4 in the same manner as the weather-resistant particles 1 of the first embodiment. The third coating layer to be formed may be formed by one layer or two or more layers.
The kind of the metal compound, the coating amount of the third coating layer in the first coating layer 3, the thickness of the third coating layer, and the like are the same as those of the weather resistant particle 1 of the first embodiment. The description is omitted.

The weather resistant particles of the present embodiment are also excellent in transparency and ultraviolet shielding properties as well as the long term weather resistance, similar to the weather resistant particles of the first embodiment.
In particular, since the surface-treated ultraviolet shielding particles 13 are used, the transparency is further improved and the long-term weather resistance is also improved.

  The “weathering particle-containing dispersion”, “weathering particle-containing resin composition”, “weathering film” and “weathering substrate” of this embodiment are the weathering particles 1 of the first embodiment. The only difference is that the weatherable particles 11 of this embodiment are used instead of the “weatherable particle-containing dispersion”, “weatherable particle-containing resin composition”, and “weatherability” of the first embodiment. The same effects as the “film” and “weather-resistant substrate” can be obtained.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited by these Examples.

[Example 1]
"Preparation of weather-resistant particles and dispersion containing weather-resistant particles"
Surface-treated titanium oxide (titanium oxide having a surface-treated layer made of aluminum hydroxide) TTO-51A (primary particle size: 10 to 30 nm, manufactured by Ishihara Sangyo Co., Ltd.) 10 parts by mass, 84 parts by mass of 2-propanol, tetramethoxysilane 5.0 parts by mass and 1.0 part by mass of water were dispersed with a ball mill for 4 hours.

Next, 10 parts by mass of methoxy group-containing silicone resin KR-213 (manufactured by Shin-Etsu Silicone Co., Ltd.) was added and further mixed and stirred.
Subsequently, 2-propanol was added to adjust the concentration of the surface-treated titanium oxide to 5% by mass to obtain a weatherable particle-containing dispersion of Example 1 having high transparency.

  The coating amount of the first coating layer (silica layer) in the weather resistant particles is 31% by volume (calculated value based on tetramethoxysilane concentration) with respect to the surface-treated titanium oxide, and the coating amount of the second coating layer (silicone layer) The amount was 213% by volume (calculated value based on the silicone concentration) based on the surface-treated titanium oxide.

When the weatherable particles thus obtained were observed using a scanning electron microscope S-4000 (manufactured by Hitachi High-Tech), the average particle size was 35 nm.
Further, the thickness of the first coating layer (silica layer) in this weather resistant particle is 2 nm (calculated value based on tetramethoxysilane concentration), and the thickness of the second coating layer (silicone layer) is 8 nm (based on silicone resin concentration). Calculated value).

  The average dispersed particle size (d50) of this weather-resistant particle-containing dispersion was measured using a dynamic light scattering particle size distribution analyzer, Microtrac UPA150 (manufactured by Microtrac), and as a result, it was 60 nm.

“Preparation of weatherable particle-containing resin composition”
30.0 parts by mass of the above weather-resistant particle-containing dispersion, 27.0 parts by mass of urethane-acrylate resin UV-7630B (manufactured by Nippon Synthetic Chemical), photoinitiator Irgacure 184 (manufactured by Ciba Specialty Chemicals) 2.0 Mass parts, 0.6 parts by mass of hindered amine light stabilizer Tinuvin 123 (manufactured by Ciba Specialty Chemicals) and 40.4 parts by mass of methyl isobutyl ketone were mixed to obtain a weather resistant particle-containing resin composition of Example 1.

"Formation of weathering film"
The above weather resistant particle-containing resin composition was applied to a polycarbonate substrate (length 100 × width 100 × thickness 1 mm) by bar coating so that the dry film thickness was 5 μm, thereby forming a coating film. Subsequently, this base material with a coating film was dried at 80 ° C. for 3 minutes using a hot air drying furnace. Next, the substrate with the coating film was irradiated with ultraviolet rays having an energy of 700 mJ / cm ² using an ultraviolet irradiation device of a high-pressure mercury lamp to form a weather resistant film on the polycarbonate substrate.

As a result of measuring the total light transmittance and haze value of the obtained weather-resistant film using a haze meter NDH2000 (manufactured by Nippon Denshoku), the total light transmittance was 89% and the haze value was 0.5%. .
Moreover, the result of having measured visible-light transmittance using the spectrophotometer V-570 (made by JASCO Corporation) is shown in FIG.
Further, using an i-super UV tester SUV-W13 (Iwasaki Electric Co., Ltd.), the change in yellowness (ΔYI) before and after the weather-resistant film was irradiated with ultraviolet rays (300 nm-400 nm 90 mW / cm ² ) for 30 hours. Value) was measured, and this ΔYI value was 10. Moreover, as a result of visually measuring the weather-resistant film after irradiation, no whitening was observed in the appearance.

[Example 2]
Except for changing the silicone resin KR-213 containing a methoxy group from 10 parts by mass to 6 parts by mass, in the same manner as in Example 1, the weather resistant particles, the weather resistant particle-containing dispersion, and the weather resistant particles of Example 2 were used. A contained resin composition and a weather resistant film were obtained.
The coating amount of the first coating layer (silica layer) in the weather resistant particles is 31% by volume (calculated value based on tetramethoxysilane concentration) with respect to the surface-treated titanium oxide, and the second coating layer (silicone layer). The coating amount was 128% by volume (calculated value based on the silicone concentration) with respect to the surface-treated titanium oxide.

  The properties of the weatherable particles and the weatherable particle-containing dispersion thus obtained were measured in the same manner as in Example 1. As a result, the average particle size was 30 nm, the average dispersed particle size was 80 nm, and the silicon oxide coating layer The thickness was 2 nm, and the thickness of the silicone layer was 5 nm.

Further, when the total light transmittance and haze value of the obtained weather-resistant film were measured in the same manner as in Example 1, the total light transmittance was 89% and the haze value was 0.6.
Further, in the same manner as in Example 1, the measurement result of ΔYI value when irradiated with ultraviolet rays for 30 hours was 10, and no whitening was observed in the appearance.
Moreover, when the visible light transmittance was measured using a spectrophotometer V-570 (manufactured by JASCO Corp.), a result very similar to the weather resistant film of Example 1 was obtained.

Furthermore, using the iSuper UV tester SUV-W13 (Iwasaki Electric Co., Ltd.), the above weather-resistant film was irradiated with ultraviolet rays and rain (300 nm-400 nm 18 mW / cm ² of ultraviolet rays for 100 minutes and then 100 minutes after rain). The change in yellowness (ΔYI value) before and after exposure for 96 hours under the condition of 1 cycle was measured and found to be 20. Further, as a result of visually measuring the weather-resistant film after exposure, no whitening was observed in the appearance.

[Example 3]
"Preparation of weather-resistant particles and dispersion containing weather-resistant particles"
Surface-treated titanium oxide (titanium oxide having a surface-treated layer made of aluminum hydroxide) TTO-51A (primary particle size: 10 to 30 nm, manufactured by Ishihara Sangyo Co., Ltd.) 10 parts by mass, 84 parts by mass of 2-propanol, tetramethoxysilane 5.0 parts by mass and 1.0 part by mass of water were dispersed with a ball mill for 4 hours.

Next, 4 parts by mass of alumina alcoholate ASBD (manufactured by Kawaken Fine Co., Ltd.) was added and mixed, and then 10 parts by mass of silicone resin KR-213 (manufactured by Shin-Etsu Silicone Co., Ltd.) containing a methoxy group was further added. The mixture was stirred.
Subsequently, 2-propanol was added to adjust the concentration of the surface-treated titanium oxide to 5% by mass to obtain a weatherable particle-containing dispersion of Example 3 having high transparency.

  The coating amount of the first coating layer (silica layer) in the weather resistant particles is 31% by volume (calculated value based on tetramethoxysilane concentration) with respect to the surface-treated titanium oxide, and the coating amount of the alumina compound is the surface-treated titanium oxide. On the other hand, the coating amount of 16 volume% (calculated value based on alumina alcoholate concentration) and the second coating layer (silicone layer) was 213 volume% (calculated value based on silicone concentration) with respect to the surface-treated titanium oxide.

  Moreover, when the characteristics of the obtained weather resistant particle-containing dispersion were determined in the same manner as in Example 1, the average particle size was 35 nm, the average dispersed particle size was 180 nm, and the thickness of the first coating layer (silica layer) was 2 nm, the alumina compound layer was 1 nm, and the thickness of the silicone layer was 8 nm.

"Formation of weathering film"
A weather-resistant film was formed on a polycarbonate substrate in the same manner as in Example 1 using the above-mentioned weather-resistant particle-containing dispersion.
When the total light transmittance and haze value of the obtained weather-resistant film were measured in the same manner as in Example 1, the total light transmittance was 89% and the haze value was 0.3.
Moreover, as a result of measuring the ΔYI value when irradiated with ultraviolet rays for 30 hours in the same manner as in Example 1, it was 5, and no whitening was observed in the appearance.
Moreover, when the visible light transmittance was measured using a spectrophotometer V-570 (manufactured by JASCO Corp.), a result very similar to the weather resistant film of Example 1 was obtained.

[Example 4]
“Preparation of weatherable particle-containing resin composition”
30.0 parts by mass of the weatherable particle-containing dispersion obtained in Example 3, 27.0 parts by mass of urethane-acrylate resin UV-7630B (manufactured by Nippon Synthetic Chemical), photoinitiator Irgacure 184 (Ciba Specialty Chemicals) 2.0 parts by mass and 41.0 parts by mass of methyl isobutyl ketone were mixed to obtain a weatherable particle-containing resin composition of Example 4.

A weather resistant film of Example 4 was obtained in the same manner as in Example 1 using the obtained weather resistant particle-containing resin composition.
As in Example 1, the ΔYI value measured when irradiated with ultraviolet rays for 30 hours was 10. As a result, the appearance was not whitened.

[Comparative Example 1]
"Surface treatment of titanium oxide and preparation of dispersion liquid"
Surface-treated titanium oxide TTO-51A (primary particle size: 10 to 30 nm, manufactured by Ishihara Sangyo Co., Ltd.) 10 parts by mass, 84 parts by mass of 2-propanol, 5.0 parts by mass of tetramethoxysilane, and 1.0 part by mass of water are ball milled. For 4 hours.
Subsequently, 2-propanol was added to adjust the concentration of the surface-treated titanium oxide to 5% by mass to obtain a surface-treated titanium oxide dispersion of Comparative Example 1 having no silicone layer.

The coating amount of the first coating layer (silica layer) of the obtained particles was 31% by volume (calculated value based on tetramethoxysilane concentration) with respect to the surface-treated titanium oxide.
Further, when this surface-treated titanium oxide dispersion was observed and measured in the same manner as in Example 1, the average particle size was 20 nm, the average dispersed particle size was 100 nm, and the thickness of the first coating layer (silica layer) was 2 nm. It was.

Further, using this surface-treated titanium oxide dispersion, a titanium oxide-containing resin composition and a weather resistant film were obtained in the same manner as in Example 1.
When the total light transmittance and haze value of the obtained weather-resistant film were measured in the same manner as in Example 1, the total light transmittance was 89% and the haze value was 0.8.
When this weather resistant film was irradiated with ultraviolet rays for 30 hours in the same manner as in Example 1, the ΔYI value was 15, and no whitening was observed in the appearance.
Further, when the obtained weather-resistant film was exposed to ultraviolet irradiation and rainfall for 96 hours in the same manner as in Example 2, the ΔYI value was 25, and marked whitening was observed in the appearance.

[Comparative Example 2]
"Production of surface-treated titanium oxide-containing resin composition"
30.0 parts by mass of the surface-treated titanium oxide dispersion of Comparative Example 1, 27.0 parts by mass of urethane-acrylate resin UV-7630B (manufactured by Nippon Synthetic Chemical), photoinitiator Irgacure 184 (manufactured by Ciba Specialty Chemicals) 2 0.0 part by mass and 41.0 parts by mass of methyl isobutyl ketone were mixed to obtain a surface-treated titanium oxide-containing resin composition of Comparative Example 2 containing no light stabilizer.
Using the obtained surface-treated titanium oxide-containing resin composition, a weather resistant film was obtained in the same manner as in Example 1.

When the total light transmittance and haze value of the obtained weather-resistant film were measured in the same manner as in Example 1, the total light transmittance was 89% and the haze value was 0.8.
Further, as in Example 1, the ΔYI value when irradiated with ultraviolet rays for 30 hours was 50, and the appearance was slightly whitened.

[Comparative Example 3]
Instead of surface-treated titanium oxide TTO-51A (primary particle size: 10 to 30 nm, manufactured by Ishihara Sangyo Co., Ltd.), titanium oxide TTO-51N without a surface treatment layer (primary particle size: 10 to 30 nm, manufactured by Ishihara Sangyo Co., Ltd.) A titanium oxide dispersion, a titanium oxide-containing resin composition, and a weather resistant film were obtained in the same manner as in Comparative Example 1 except that was used.

When this titanium oxide dispersion was observed and measured in the same manner as in Example 1, the average particle size was 20 nm, the average dispersed particle size was 300 nm, and the dispersibility was poor.
When the total light transmittance and haze value of the obtained weather-resistant film were measured in the same manner as in Example 1, the total light transmittance was 81% and the haze value was 3.0, and the transparency was poor. That is, by not having a surface treatment layer made of aluminum hydroxide, it was confirmed that the dispersibility in the dispersion was deteriorated and the transparency was deteriorated.

[Comparative Example 4]
"Production of resin composition"
Urethane-acrylate resin UV-7630B (manufactured by Nippon Synthetic Chemical) 30.0 parts by mass, photoinitiator Irgacure 184 (manufactured by Ciba Specialty Chemicals) 2.0 parts by mass, hindered amine light stabilizer Tinuvin 123 (Ciba Specialty Chemicals) (Made by company) 0.6 mass part and methyl isobutyl ketone 41.0 mass part were mixed, and the resin composition which does not contain a weather-resistant particle | grain was obtained.
A coating film was obtained in the same manner as in Example 1 using the obtained resin composition.

When the total light transmittance and haze value of the obtained coating film were measured in the same manner as in Example 1, the total light transmittance was 89% and the haze value was 0.2.
Further, as in Example 1, the ΔYI value when irradiated with ultraviolet rays for 30 hours was 55, and the weather resistance was poor. No whitening was observed in the appearance.

  The weather resistant particle of the present invention is a first particle comprising 5% by volume to 60% by volume of silicon oxide on the surface of an ultraviolet shielding particle having an average primary particle diameter of 5 nm or more and 100 nm or less. A coating layer is formed, and on the surface of the first coating layer, a second coating layer made of silicon resin of 15 volume% or more and 300 volume% or less with respect to the volume of the ultraviolet shielding particles is formed. By making the diameter 6 nm or more and 200 nm or less, the ultraviolet shielding ability can be maintained over a long period of time, there is no possibility of deterioration, and the transparency and the ultraviolet shielding ability can be maintained over a long period of time. In addition, since it can also be excellent in long-term weather resistance, it can be used not only for materials exposed to sunlight, especially for outdoor base materials that continue to be exposed to sunlight during the day. Even in various members that are required to have weather resistance to ultraviolet rays, the coating range for imparting weather resistance to sunlight, particularly ultraviolet rays, is increased on the surfaces of these various members, thereby expanding the applicable range and its industrial value is great. .

DESCRIPTION OF SYMBOLS 1 Weather resistance particle | grains 2 Ultraviolet shielding particle 3 1st coating layer 4 2nd coating layer 11 Weather resistance particle | grains 12 Surface treatment layer 13 Surface treatment ultraviolet shielding particle

Claims (7)

On the surface of the ultraviolet shielding particles having an average primary particle diameter of 5 nm or more and 100 nm or less, a first coating layer made of silicon oxide of 5 vol% or more and 60 vol% or less with respect to the ultraviolet shielding particles is formed. On the surface of the coating layer 1, a second coating layer made of silicon resin of 15 volume% or more and 300 volume% or less with respect to the volume of the ultraviolet shielding particles is formed,
Weather resistant particles having an average particle size of 6 nm or more and 200 nm or less.   2. The weather resistant particle according to claim 1, wherein a surface treatment layer mainly composed of aluminum hydroxide is formed on a surface of the ultraviolet shielding particle.   The weatherable particle according to claim 1 or 2, wherein a third coating layer made of a metal compound is formed between the first coating layer and the second coating layer.   A weather-resistant particle-containing dispersion comprising the weather-resistant particles according to any one of claims 1 to 3 dispersed in a solvent.   A weather-resistant particle-containing resin composition comprising the weather-resistant particles according to any one of claims 1 to 3 and a resin.   A weather-resistant film comprising the weather-resistant particle-containing resin composition according to claim 5.   A weather-resistant substrate comprising the weather-resistant film according to claim 6.

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