JP5514487B2 - Water-dispersed sol of high refractive index metal oxide fine particles, preparation method thereof, and organic solvent-dispersed sol of the metal oxide fine particles - Google Patents

Description

The present invention relates to a metal oxide fine particle having a high refractive index, more specifically, a metal oxide fine particle having a high refractive index obtained by coating a titanium-based fine particle having a rutile crystal structure with a silica-based oxide or a silica-based composite oxide. And an organic solvent dispersion sol containing the metal oxide fine particles.

  In recent years, as a material for optical base materials such as eyeglass lenses, plastic base materials are increasingly used in place of inorganic glass base materials. This is because the plastic substrate has excellent characteristics in terms of lightness, impact resistance, processability, dyeability, and the like. However, the plastic substrate has a drawback that it is easily damaged compared to an inorganic glass substrate.

  Therefore, in order to avoid this drawback, a silicone-based curable coating film, that is, a hard coat layer film is usually provided on the surface of an optical lens using a plastic substrate. Furthermore, when a plastic substrate having a relatively high refractive index is used as the material of the optical lens, in order to avoid interference of light (appearing as interference fringes) occurring between the plastic substrate and the hard coat layer film. The hard coat layer film is treated with a metal oxide fine particle so that its refractive index matches that of the plastic substrate.

Various developments have been made and many applications have been made for coating solutions for forming a silicone-based curable coating film having such characteristics, for example, a hard coat layer film on a plastic substrate.
Also, when manufacturing optical base materials such as eyeglass lenses (plastic lens base materials, etc.), it is colorless and transparent and has a high refractive index, and also has scratch resistance, abrasion resistance, impact resistance, weather resistance, light resistance, There is a need for water-dispersed sols and organic solvent sols containing fine metal oxide particles as coating solutions and raw material compositions for forming curable coatings with excellent properties such as sweat resistance, hot water resistance, adhesion, and dyeability. Many applications have been filed for this as well.

  For example, Patent Document 1 discloses metal oxide fine particles containing at least one of silica, iron oxide, titanium oxide, cerium oxide, zirconium oxide, antimony oxide, zinc oxide and tin oxide, a mixture thereof, or a composite oxide thereof. A high refractive index coating composition containing metal oxide fine particles and an organosilicon compound is disclosed. However, although a curable coating film formed using a coating solution containing these metal oxide fine particles has a relatively high refractive index, it cannot be said that it has excellent weather resistance.

  As the background, in optical base materials such as eyeglass lenses, the thickness of plastic lenses and so on has been reduced in order to reduce weight, and as a result, the higher refractive index of coating films has been promoted. However, the weather resistance of the coating film was impaired by the titanium oxide having photocatalytic activity.

Therefore, the present applicants have disclosed a dispersion sol containing fine particles formed by coating the surface of a core particle containing a titanium-based oxide with a composite oxide of silicon, zirconium and / or aluminum, and the fine particles and an organosilicon compound. Has been developed and applied for a coating solution for forming a coating film. That is, the photocatalytic activity of the titanium oxide contained in the core particles is suppressed by coating the core particles containing the titanium-based oxide with the composite oxide.

For example, in Patent Document 2, (1) fine particles having titanium oxide fine particles as nuclei and surfaces thereof coated with zirconium oxide and silicon oxide, and (2) complex oxide fine particles made of a solid solution of titanium oxide and zirconium oxide are used as nuclei. Fine particles whose surfaces are coated with silicon oxide, (3) fine particles whose surface is coated with silicon oxide and zirconium oxide and / or aluminum oxide, using fine oxide fine particles of titanium and silicon as a nucleus, and (4) titanium. Dispersion sol containing fine particles of silicon and zirconium composite oxide as a core and coated with at least one of silicon oxide, zirconium oxide and aluminum oxide on the surface, and for forming a film containing the fine particles and an organosilicon compound A coating solution is disclosed. That is, in the invention according to Patent Document 2, a core-shell structure obtained by coating the surface of titanium-containing core particles having an anatase type crystal structure with at least one selected from silicon oxide, zirconium oxide, and aluminum oxide. Metal oxide fine particles are used.

Patent Document 3 includes composite oxide fine particles in which a composite solid solution oxide of titanium and tin is used as a core particle and the surface thereof is coated with a composite oxide of silicon oxide and zirconium and / or aluminum oxide. A coating solution for forming a film containing a dispersion sol and the fine particles and an organosilicon compound is disclosed. That is, in the invention according to Patent Document 3, a core-shell obtained by coating the surface of titanium-containing core particles having a rutile crystal structure with a composite oxide of silicon oxide and zirconium and / or aluminum oxide. Metal oxide fine particles having a structure are used.

If the metal oxide fine particles described in Patent Document 2 and Patent Document 3 are used, in the range of refractive index of 1.52 to 1.67, not only has excellent weather resistance, For example, scratch resistance, abrasion resistance, impact resistance, light resistance, sweat resistance, hot water resistance, adhesion, transparency, dyeability, etc. be able to.
However, in recent years, optical substrates (such as plastic lens substrates) having a refractive index of 1.70 or more, more specifically 1.71 to 1.81, have been developed, and a curable coating film corresponding to this is formed. However, in order to increase the refractive index of the coating film, the content of titanium contained in the core particles is required to increase the refractive index of the coating film. It was necessary to further increase the thickness of the coating layer (that is, the coating layer on the surface of the titanium-containing core particle). As a result, although a curable coating film having a relatively high refractive index of about 1.70 was obtained, its weather resistance and light resistance tended to be impaired. Moreover, it was difficult to obtain a curable coating film having a higher refractive index.

On the other hand, an optical lens such as a spectacle lens, in which the hard coat layer film is formed on the surface of a plastic substrate and an antireflection film is further formed thereon, has a defect that it is inferior in impact resistance. .
As means for solving this drawback, (1) a method of forming a primer layer film containing a thermosetting urethane resin and colloidal metal oxide fine particles containing titanium oxide (for example, Patent Document 4), (2 ) A method for forming a primer layer film containing polyurethane resin and metal oxide fine particles such as zinc oxide, silicon dioxide, aluminum oxide, titanium oxide, zirconium oxide, tin oxide, beryllium oxide, antimony oxide, tungsten oxide, cerium oxide ( For example, Patent Document 5) is known. Here, the metal oxide fine particles are added to adjust the refractive index of the coating film (inhibition of light interference) and improve the strength of the coating film. When the titanium content in the fine particles is increased in order to cope with the increase in the refractive index of the lens, there is a problem that the weather resistance and light resistance of the coating film deteriorate.

JP 7-325201 A JP-A-8-048940 JP 2000-204301 A JP-A-6-118203 JP-A-6-337376

The inventors of the present invention have made extensive studies on whether or not a coating solution for forming a curable coating film having a high refractive index, weather resistance and light resistance can be obtained by solving the above-mentioned problems. As a result, water-dispersed sol and organic solvent dispersion of metal oxide fine particles formed by coating silica-based oxide or silica-based composite oxide on the surface of titanium-based fine particles with a rutile-type crystal structure that has undergone special processing It has been found that sol may be used as a preparation raw material, and the present invention has been completed.
That is, the present invention relates to an aqueous dispersion sol containing metal oxide fine particles formed by coating silica-based oxides or silica-based composite oxides on the surface of specific titanium-based fine particles having a rutile-type crystal structure, and a method for preparing the same. It is intended to provide. Furthermore, an object of the present invention is to provide an organic solvent-dispersed sol containing the metal oxide fine particles.

The water-dispersed sol of high refractive index metal oxide fine particles according to the present invention has at least silica-based oxide or silica-based composite oxidation on the surface of titanium-based fine particles having an average particle diameter of 15 to 60 nm measured by a dynamic light scattering method. An aqueous dispersion sol containing metal oxide fine particles with a high refractive index coated with a material,
(1) The titanium-based fine particles are crystalline fine particles having a rutile-type crystal structure, and have an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm and a specific surface area of 70 to 155 m ² / g. And the refractive index is in the range of 2.2 to 2.7,
(2) The coating layer has a refractive index lower by 0.2 or more than the refractive index of the titanium-based fine particles, and the refractive index of the metal oxide fine particles provided with the coating layer is 2.0-2. 5 and (3) the water-dispersed sol contains 1 to 30% by weight of the metal oxide fine particles, and the turbidity is in the range of 0.1 to 10 cm ^−1. Yes.

The titanium-based fine particles are preferably those obtained by firing and pulverizing composite oxide particles containing titanium and tin and / or silicon.
The silica-based oxide is preferably silicon dioxide.
Furthermore, the silica-based composite oxide is preferably a silica-based composite oxide containing silicon and at least one metal element selected from zirconium, antimony, tin, and aluminum.
The titanium-based fine particles have a distribution frequency of relatively coarse titanium-based fine particles having a particle diameter of 100 nm or more in a particle size frequency distribution when the fine particles are measured by a dynamic light scattering method, of 1% or less. It is preferable.

The titanium-based fine particles have a (310) crystal plane spacing d ¹ in the range of 0.1440 to 0.1460 nm, as determined from X-ray diffraction of the fine particles, and (301) a crystal plane spacing d ^2. Is preferably in the range of 0.1355 to 0.1370 nm.
Further, the titanium-based fine particles, as determined by X-ray diffraction of the fine particles, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ² ) is preferably in the range of 9/100 to 20/100.

The composite oxide particles are prepared by subjecting a mixed aqueous solution containing titanic acid peroxide and potassium stannate and / or silicon compound to an autoclave and hydrothermally treating at a temperature of 150 to 250 ° C. to obtain titanium, tin and / or It is preferable that a composite oxide containing silicon is produced, and then the composite oxide is dried and granulated.
Here, the silicon compound is preferably at least one selected from silica fine particles, silicic acid, and silicon alkoxide.
Furthermore, the composite oxide particles are preferably obtained by simultaneously drying and granulating the composite oxide by subjecting the mixed aqueous solution containing the composite oxide to spray drying using a spray dryer.

The titanium-based fine particles are baked at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to generate composite oxide particles having an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm. Then, the composite oxide particles are preferably subjected to pulverization using a pulverizer.
The titanium-based fine particles were measured by a dynamic light scattering method after dispersing the finely divided composite oxide fine particles in pure water or ultrapure water and then using the aqueous dispersion in a wet classifier. It is preferable that at least the coarse particles having a particle diameter of 100 nm or more are separated and removed.

The metal oxide fine particles are obtained by mixing at least one silicon compound selected from silicon alkoxide and silicic acid in an aqueous dispersion containing the titanium fine particles, and then hydrolyzing the silicon compound to thereby produce the titanium fine particles. The surface is preferably coated with a silica-based oxide.
In addition, the metal oxide fine particles include at least one silicon compound selected from silicon alkoxide and silicic acid, zirconate peroxide, antimonate and aluminate in an aqueous dispersion containing the titanium-based fine particles. It is preferable that at least one metal compound selected from the above is mixed, the silicon compound and the metal compound are then hydrolyzed, and the surface of the titanium-based fine particles is coated with a silica-based composite oxide.
Here, the silicon alkoxide is preferably tetramethoxysilane or a condensate thereof, or tetraethoxysilane or a condensate thereof.
Further, when the weight of the titanium-based fine particles is represented by C and the weight of the coating layer is represented by S, the weight ratio (S / C) is 1/100 in terms of oxide. It is preferable that the surface of the titanium-based fine particles is coated with the silica-based oxide or the silica-based composite oxide so as to be in a range of ˜50 / 100.
The method for preparing an aqueous dispersion sol of metal oxide fine particles according to the present invention,
The average particle diameter measured by a dynamic light scattering method is 15 to 60 nm, and the surface of titanium oxide fine particles satisfying at least one of the following requirements (i) and (ii) is coated with at least a silica-based oxide. A method for preparing an aqueous dispersion sol containing metal oxide fine particles,
(A) A mixed aqueous solution containing peroxytitanic acid and potassium stannate and / or silicon compound is placed in an autoclave and hydrothermally treated at a temperature of 150 to 250 ° C. to contain titanium and tin and / or silicon. Producing a composite oxide;
(B) A step of obtaining composite oxide particles having an average particle diameter of 1 to 80 μm containing titanium and tin and / or silicon by drying and granulating the composite oxide produced in the step (a). ,
(C ′) The composite oxide particles obtained in the step (b) are baked at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere, and a composite having an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm. Producing oxide particles;
(D ′) a step of subjecting the composite oxide particles produced in the step (c ′) to a pulverizer and pulverization, and dispersing the pulverized one in pure water or ultrapure water to obtain an aqueous dispersion;
(F) The aqueous dispersion obtained in the step (d ′) or the dispersion is subjected to a wet classifier to separate at least coarse particles having a particle diameter of 100 nm or more as measured by a dynamic light scattering method. -By mixing (i) at least one silicon compound selected from silicon alkoxide and silicic acid into the aqueous dispersion obtained through the step (e) to be further removed, and hydrolyzing the silicon compound A step of obtaining an aqueous dispersion sol containing metal oxide fine particles in which the surface of the titanium oxide fine particles is coated with a silica-based oxide.
It is characterized by including.
Requirement (i): The interplanar spacing d ¹ of the (310) crystal plane determined from X-ray diffraction of the titanium oxide-based fine particles is in the range of 0.1440 to 0.1460 nm, and (301) the interplanar spacing of the crystal plane. d ² is in the range of 0.1355~0.1370nm.
Requirements (ii): wherein as determined by X-ray diffraction of the titanium oxide-based fine particles, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ² ) is in the range of 9/100 to 20/100.
Furthermore, the method for preparing an aqueous dispersion sol of metal oxide fine particles according to the present invention includes:
The average particle diameter measured by the dynamic light scattering method is 15 to 60 nm, and the surface of the titanium oxide fine particles satisfying at least one of the above requirements (i) and (ii) is coated with at least a silica-based composite oxide. A method for preparing an aqueous dispersion sol containing metal oxide fine particles,
(A) A mixed aqueous solution containing peroxytitanic acid and potassium stannate and / or silicon compound is placed in an autoclave and hydrothermally treated at a temperature of 150 to 250 ° C. to contain titanium and tin and / or silicon. Producing a composite oxide;
(B) A step of obtaining composite oxide particles having an average particle diameter of 1 to 80 μm containing titanium and tin and / or silicon by drying and granulating the composite oxide produced in the step (a). ,
(C ′) The composite oxide particles obtained in the step (b) are baked at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere, and a composite having an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm. Producing oxide particles;
(D ′) a step of subjecting the composite oxide particles produced in the step (c ′) to a pulverizer and pulverization, and dispersing the pulverized one in pure water or ultrapure water to obtain an aqueous dispersion;
(F) The aqueous dispersion obtained in the step (d ′) or the dispersion is subjected to a wet classifier to separate at least coarse particles having a particle diameter of 100 nm or more as measured by a dynamic light scattering method. -In the aqueous dispersion obtained further through the removing step (e), (i) at least one silicon compound selected from silicon alkoxide and silicic acid, zirconate peroxide, antimonate, stannic acid A metal in which at least one metal compound selected from a salt and an aluminate is mixed and the surface of the titanium oxide fine particles is coated with a silica-based composite oxide by hydrolyzing the silicon compound and the metal compound. Process for obtaining water-dispersed sol containing fine oxide particles
A method for preparing an aqueous dispersion sol of metal oxide fine particles, comprising:

The method for preparing an aqueous dispersion sol of high refractive index metal oxide fine particles according to the present invention,
A method for preparing an aqueous dispersion sol containing high refractive index metal oxide fine particles obtained by coating the surface of titanium fine particles having an average particle diameter of 15 to 60 nm measured by a dynamic light scattering method with at least a silica-based oxide. There,
(A) A mixed aqueous solution containing peroxytitanic acid and potassium stannate and / or silicon compound is placed in an autoclave and hydrothermally treated at a temperature of 150 to 250 ° C. to contain titanium and tin and / or silicon. Producing a composite oxide;
(B) A step of obtaining composite oxide particles having an average particle diameter of 1 to 80 μm containing titanium and tin and / or silicon by drying and granulating the composite oxide produced in the step (a). ,
(C) a step of firing the composite oxide particles obtained in the step (b) at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain titanium-based particles composed of a fired product of the composite oxide particles;
(D) The titanium-based particles obtained in the step (c) are pulverized to form titanium-based fine particles having an average particle diameter of 15 to 60 nm as measured by a dynamic light scattering method. Obtaining a water-dispersed sol dispersed in water or ultrapure water;
(E) If necessary, subject the aqueous dispersion obtained in the step (d) to a wet classifier to separate and remove at least coarse particles having a particle diameter of 100 nm or more as measured by a dynamic light scattering method. And (f) mixing (i) at least one silicon compound selected from silicon alkoxide and silicic acid into the aqueous dispersion obtained in step (d) or step (e), It includes a step of obtaining a water-dispersed sol containing metal oxide fine particles in which the surface of the titanium-based fine particles is coated with a silica-based oxide by hydrolyzing a silicon compound.

Furthermore, the method for preparing an aqueous dispersion sol of high refractive index metal oxide fine particles according to the present invention is as follows:
Method for preparing water-dispersed sol containing high refractive index metal oxide fine particles obtained by coating the surface of titanium fine particles having an average particle diameter of 15 to 60 nm measured by dynamic light scattering method with at least silica-based composite oxide Because
(A) A mixed aqueous solution containing peroxytitanic acid and potassium stannate and / or silicon compound is placed in an autoclave and hydrothermally treated at a temperature of 150 to 250 ° C. to contain titanium and tin and / or silicon. Producing a composite oxide;
(B) A step of obtaining composite oxide particles having an average particle diameter of 1 to 80 μm containing titanium and tin and / or silicon by drying and granulating the composite oxide produced in the step (a). ,
(C) a step of firing the composite oxide particles obtained in the step (b) at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain titanium-based particles composed of a fired product of the composite oxide particles;
(D) The titanium-based particles obtained in the step (c) are pulverized to form titanium-based fine particles having an average particle diameter of 15 to 60 nm as measured by a dynamic light scattering method. Obtaining a water-dispersed sol dispersed in water or ultrapure water;
(E) If necessary, subject the aqueous dispersion obtained in the step (d) to a wet classifier to separate and remove at least coarse particles having a particle diameter of 100 nm or more as measured by a dynamic light scattering method. And (f) in the aqueous dispersion obtained in the step (d) or the step (e), (i) at least one silicon compound selected from silicon alkoxide and silicic acid, and zirconic peroxide At least one metal compound selected from a salt, antimonate, stannate and aluminate is mixed, and the surface of the titanium-based fine particles is silica-based by hydrolyzing the silicon compound and the metal compound. It includes a step of obtaining an aqueous dispersion sol containing metal oxide fine particles coated with a complex oxide.

In the method for preparing an aqueous dispersion sol, the silicon compound used in the step (a) is preferably at least one selected from silica fine particles, silicic acid, and silicon alkoxide.
The pH of the mixed aqueous solution obtained in the step (a) is preferably adjusted in the range of 3 to 10 before being used in the step (b).
Further, in the step (b), the mixed aqueous solution obtained in the step (a) is spray-dried using a spray dryer, whereby the composite oxide contained in the mixed aqueous solution is simultaneously dried and granulated. It is preferable.
Furthermore, it is preferable that the silicon alkoxide used in the step (a) and the step (f) is tetramethoxysilane or a condensate thereof, or tetraethoxysilane or a condensate thereof.
Further, by adding an anion exchange resin and / or a cation exchange resin to the water dispersion sol obtained in the step (f) and stirring, the ionized substance contained in the water dispersion sol is removed. It is preferable to keep it.

The organic solvent dispersion sol of the high refractive index metal oxide fine particles according to the present invention is characterized in that the high refractive index metal oxide fine particles contained in the aqueous dispersion sol are dispersed in an organic solvent.
Examples of the organic solvent include alcohols such as methanol, ethanol, butanol, propanol, isopropyl alcohol, ethers such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl ethyl ketone, γ- It is preferably at least one organic compound selected from ketones such as butyrolactone.
In addition, the organic solvent-dispersed sol is obtained by subjecting the water-dispersed sol of the above-described high refractive index metal oxide fine particles to a solvent replacement device to replace water contained in the water-dispersed sol with an organic solvent. preferable.

The high refractive index metal oxide fine particles contained in the dispersion sol according to the present invention itself has a high refractive index of 2.0 to 2.5, and further its photocatalytic activity is quite low. Not only has a very low possibility of degrading a curable coating film or a plastic substrate formed using a coating solution containing the fine particles, but also causes blue discoloration (that is, blueing) to the curable coating film. There is an advantage that there is very little possibility of making it. This is because the titanium-based fine particles contained in the metal oxide fine particles are crystalline fine particles having special physical properties. That is, the titanium-based fine particles have an average particle diameter measured by a dynamic light scattering method in the range of 15 to 60 nm, and themselves have a refractive index of 2.2 to 2.7. Furthermore, it has a rutile crystal structure having a crystallite diameter measured by an X-ray diffraction method in the range of 7.5 to 14.0 nm and a specific surface area of 70 to 155 m ² / g.
More specifically, since the titanium-based fine particles are fired at a relatively high temperature, that is, a temperature of 300 to 800 ° C., the crystallinity (in the present invention, expressed by the X-ray diffraction crystallite diameter). As a result, the refractive index of the fine particles can be increased. Furthermore, since the specific surface area of the fine particles decreases as the crystallinity increases, the amount of OH groups present on the surface of the fine particles decreases. Along with this, OH groups (for example, .OH) that become free radicals when exposed to ultraviolet light are reduced, and as a result, the above-mentioned photocatalytic activity can be weakened.

However, since the titanium-based fine particles are pulverized with the refractive index increased by baking as described above, the light reflection at the particle surface increases, resulting in an increase in light scattering. was there. Therefore, in the present invention, the surface of the fine particles is coated with silica-based oxide or silica-based composite oxide to suppress this. This suppression effect is expressed as turbidity of the water-dispersed sol in the present invention. That is, the water-dispersed sol containing high-refractive-index metal oxide fine particles with almost no light scattering obtained in this way has little turbidity and is almost transparent or close thereto.
Furthermore, when the above-described coating layer, that is, a coating layer made of a silica-based oxide or a silica-based composite oxide is present, an effect of further suppressing the photocatalytic activity of the titanium-based fine particles can be achieved.

If a coating liquid for optical substrates using a water-dispersed sol or organic solvent-dispersed sol containing such high refractive index metal oxide fine particles as a raw material composition (for example, a coating liquid for forming a hard coat layer film) is used, A curable coating film having a high refractive index of 1.70 or more, particularly 1.71 to 1.81, which is highly desired by the recent plastic lens industry, etc., and excellent in weather resistance and light resistance is provided on the substrate. Can be easily formed. More specifically, even if a plastic lens substrate having a high refractive index of 1.71 to 1.81 is used as the substrate, it occurs between the plastic lens substrate and the coating film. Light interference (appears as interference fringes) can be easily suppressed, and it has excellent weather resistance and light resistance that could not be obtained with conventional metal oxide fine particles, despite its high refractive index. A curable coating film can be easily formed on a substrate.
In addition, since an aqueous dispersion sol containing high refractive index metal oxide fine particles having a low light scattering rate is used as a raw material composition, a colorless and transparent curable coating film having a haze of 0.5% or less is formed on the substrate. Can be formed. Furthermore, it is possible to form a curable coating film excellent in properties such as scratch resistance, abrasion resistance, impact resistance, sweat resistance, hot water resistance, adhesion, dyeability, and fading resistance on a substrate. .
Therefore, the coating liquid for an optical substrate prepared using the dispersion sol according to the present invention has a curable coating film such as a hard coat layer film or a primer layer film on an optical substrate such as a plastic lens substrate. It can be suitably used when forming.

In addition, the curable coating film obtained using the said coating liquid for optical base materials is equipped with the characteristic as shown below.
(1) The content of the high refractive index metal oxide fine particles is 35 to 60% by weight with respect to the total solid content (total amount of the high refractive index metal oxide fine particles and the organosilicon compound mixed as a binder component). The curable coating film formed using the coating composition in the range has a high refractive index of 1.70 or more, more specifically 1.71 to 1.81. Therefore, even when applied to a plastic lens substrate having a high refractive index of 1.70 or more, particularly 1.71 to 1.81, the above interference fringes are not seen.
(2) Since a coating composition containing high refractive index metal oxide fine particles having a relatively low photocatalytic activity is used, the curable coating film has very excellent properties in terms of weather resistance and light resistance. doing. Here, “weather resistance” means resistance to deterioration of organic substances and plastic lens base materials contained in the coating film due to the photocatalytic activity, and “light resistance” It means the resistance to a coating film such as a hard coat layer film turning blue (so-called blueing) due to the photocatalytic activity. However, in the curable coating film, the above deterioration and bluing hardly occur.
(3) Since the coating composition containing high refractive index metal oxide fine particles having a relatively low light scattering rate is used, the curable coating film is colorless and transparent with a haze of 0.5% or less. .
(4) Furthermore, the curable coating film has excellent properties in terms of scratch resistance, abrasion resistance, impact resistance, sweat resistance, dyeability, hot water resistance, adhesion, and fading resistance. ing.

FIG. 1 shows an X-ray diffraction chart obtained by applying the sintered powder of composite oxide particles (titanium-based particles) used in Reference Example 2 to an X-ray diffractometer. FIG. 2 shows an X-ray diffraction chart obtained by applying the sintered powder of composite oxide particles (titanium-based particles) used in Reference Example 3 to an X-ray diffractometer. FIG. 3 shows an X-ray diffraction chart obtained by applying the sintered powder of composite oxide particles (titanium-based particles) used in Reference Example 5 to an X-ray diffractometer. FIG. 4 shows an X-ray diffraction chart obtained by applying the dry powder of composite oxide particles (titanium particles) used in Comparative Example 1 to an X-ray diffractometer. FIG. 5 shows an X-ray diffraction chart obtained by applying the sintered powder of composite oxide particles (titanium-based particles) used in Comparative Example 3 to an X-ray diffractometer.

Hereinafter, the water-dispersed sol of high refractive index metal oxide fine particles and the organic solvent dispersed sol of the metal oxide fine particles according to the present invention will be specifically described.
[Aqueous dispersion sol of high refractive index metal oxide fine particles]
An aqueous dispersion sol of high refractive index metal oxide fine particles according to the present invention is:
Water containing high refractive index metal oxide fine particles obtained by coating the surface of titanium fine particles having an average particle size of 15 to 60 nm measured by a dynamic light scattering method with at least silica-based oxide or silica-based composite oxide A dispersion sol,
(1) The titanium-based fine particles are crystalline fine particles having a rutile-type crystal structure, and have an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm and a specific surface area of 70 to 155 m ² / g. And the refractive index is in the range of 2.2 to 2.7,
(2) The coating layer has a refractive index lower by 0.2 or more than the refractive index of the titanium-based fine particles, and the refractive index of the metal oxide fine particles provided with the coating layer is 2.0-2. (3) The water-dispersed sol contains 1 to 30% by weight of the metal oxide fine particles, and the turbidity is in the range of 0.1 to 10.0 cm ^−1. is there.

In the present invention, the titanium-based fine particles are preferably those obtained by firing and pulverizing composite oxide particles containing titanium and tin and / or silicon.
Here, the composite oxide particles mean composite oxide particles containing titanium and tin, composite oxide particles containing titanium, tin and silicon, and a part of these compounds are schematically represented by chemical formulas. Specifically, it is as follows.

｜ ｜
-O-Ti-O-Sn-O-
｜ ｜

｜ ｜ ｜
-O-Ti-O-Sn-O-Si-O-
｜ ｜ ｜

Furthermore, the composite oxide particles are not particularly limited, but a mixed aqueous solution containing titanic acid peroxide and potassium stannate and / or silicon compound is placed in an autoclave and water is added at a temperature of 150 to 250 ° C. Heat treatment is performed to form a composite oxide containing titanium and tin and / or silicon, and then the pH of the mixed aqueous solution containing the composite oxide is adjusted to 3 to 10, and then the mixed aqueous solution is supplied to a spray dryer. It is preferably spray-dried. The silicon compound is preferably at least one selected from silica fine particles, silicic acid, and silicon alkoxide.
Here, when the hydrothermal treatment is performed at a temperature of less than 150 ° C., the crystallization of the composite oxide is difficult to proceed, so that the degree of crystallinity of the obtained particles (primary particles) becomes low and the temperature exceeds 250 ° C. This is not preferable because crystallization of the composite oxide proceeds excessively and the resulting particles easily aggregate.

Furthermore, when the pH of the mixed aqueous solution is less than 3, not only the concern about equipment corrosion increases, but also the storage stability of the mixed aqueous solution tends to decrease. The working capillary tension is increased and it becomes easy to form a hard dry powder (that is, a dry powder that is difficult to be pulverized in the subsequent pulverization step), which is not preferable. However, when the pH of the resulting mixed aqueous solution is in the range of 3 to 10, it is not always necessary to adjust this pH.
The composite oxide preferably already has a rutile crystal structure at the hydrothermal treatment stage.
The composite oxide particles are prepared by using the mixed aqueous solution in a general hot air drying apparatus without using a spray dryer, and a dried product of the composite oxide contained in the mixed aqueous solution (usually a solid solid substance). Can be prepared by subjecting it to a pulverizer and appropriately pulverizing it. However, not only is the operation complicated, but it is difficult to efficiently obtain composite oxide particles having a uniform particle diameter. Therefore, it is preferable to prepare the composite oxide particles by simultaneously drying and granulating the composite oxide contained in the mixed aqueous solution by spray-drying the mixed aqueous solution using a spray dryer. Furthermore, the composite oxide particles can be freeze-dried using freeze-dry equipment or the like.

Next, the composite oxide particles are fired at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere, and the X-ray diffraction crystallite diameter is 7.5 to 14.0 nm, preferably 8.0 to 12.0 nm. It is preferable to produce the composite oxide particles. Thereby, since the crystallinity of the composite oxide particles is increased, titanium-based particles (secondary particles) having a high refractive index and a low photocatalytic activity as shown below and having a rutile crystal structure can be obtained. .
Here, when the firing temperature is less than 300 ° C., crystallization within the particles is difficult to proceed, so that it is difficult not only to obtain particles having a desired X-ray diffraction crystallite diameter, but also the specific surface area is Since it is relatively large, dispersibility in water and the like deteriorates, and when the temperature exceeds 800 ° C., sintering of particles (especially, sintering of primary particles) proceeds rapidly, and as a result, on the particle surface. Since the specific surface area is significantly reduced, it is not preferable. Further, when the X-ray diffraction crystallite diameter is less than 7.5 nm, the crystallinity of the particles is lowered, so that a desired refractive index cannot be obtained, and the X-ray diffraction crystallite diameter is 14.0 nm. Exceeding this is not preferable because the refractive index of the particles becomes too high and light scattering on the particle surface increases.

Next, since the titanium-based particles need to be fine particles having a particle size that is small enough to be solated, the titanium-based particles are subjected to a pulverizing apparatus such as a sand mill, and so on. It is preferable to grind in the presence of an organic dispersant. Thereby, titanium-based fine particles (that is, crystalline titanium-based fine particles) having an average particle diameter of 15 to 60 nm when measured by a dynamic light scattering method are obtained.
Here, if the average particle diameter is less than 15 nm, the viscosity of the sol tends to increase when the concentration of the solid content (ie, titanium-based fine particles) contained in the sol is increased, which is not preferable. Further, when the average particle diameter exceeds 60 nm, light scattering on the particle surface increases, and as a result, the turbidity of the water-dispersed sol containing metal oxide fine particles obtained by using the fine particles may increase. If pulled, the haze of the curable coating film obtained by using this may increase, which is not preferable.
At present, titanium-based fine particles having the above properties cannot be obtained from the market, but they can be used when they become available from a third party in the future. That is, in the present invention, it is also within the scope of the right to use the titanium-based fine particles that may be provided or marketed by a third party in the future.

Since the titanium-based fine particles are produced by pulverization or pulverization / peptization as described above, coarse particles having a relatively large particle size may be included in the particle group.
Therefore, in the present invention, after the titanium-based fine particles (that is, composite oxide fine particles) pulverized as described above are dispersed in pure water or ultrapure water, the aqueous dispersion is used in a wet classifier to dynamically It is desirable to separate and remove at least coarse particles having a particle diameter of 100 nm or more as measured by a light scattering method.
That is, the titanium-based fine particles have a distribution frequency of relatively coarse titanium-based fine particles having a particle diameter of 100 nm or more in the particle size frequency distribution when the fine particles are measured by a dynamic light scattering method, preferably 1% or less. Is preferably 0.2% or less.
Here, when the distribution frequency of the coarse particles exceeds 1%, the water-dispersed sol containing metal oxide fine particles obtained from titanium-based fine particles containing such coarse particles has a turbidity exceeding 10 cm ^−1. In some cases, the transparency of the coating film obtained from the coating liquid for forming a coating film prepared using the water-dispersed sol may decrease, which is not preferable.
Thereby, titanium-based fine particles (that is, crystalline titanium-based fine particles) having an average particle diameter of 15 to 60 nm, preferably 15 to 45 nm, as measured by a dynamic light scattering method are obtained.
However, since the composite oxide particles spray-dried by using the above-mentioned spray dryer are spherical particles composed of a lump of primary particles having a small particle diameter, even if this is baked, it is applied to a grinding device such as a sand mill. If used, titanium-based fine particles having an average particle diameter of 15 to 60 nm can be easily obtained. In addition, since these particles are relatively easily pulverized, the probability that coarse particles having a particle diameter of 100 nm or more when measured by a dynamic light scattering method are reduced is reduced. It is preferable to use a spray-dried product.

In the present invention, the titanium-based fine particles are crystalline fine particles having a rutile-type crystal structure, and an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm and 70 to 155 m ² / g, preferably 90 to The specific surface area is 130 m ² / g, and the refractive index is desired to be in the range of 2.2 to 2.7, preferably 2.3 to 2.6.
Here, when the specific surface area is less than 70 m ² / g, sintering of primary particles progresses, so that the particle size increases and light scattering on the particle surface increases, or the particle surface described later. It may be difficult to coat, and if the specific surface area exceeds 155 m ² / g, the amount of OH groups present on the surface of the particles increases, resulting in the enhancement of the photocatalytic activity. Absent. Further, when the refractive index is less than 2.2, the refractive index is decreased by coating the fine particles with silica-based oxide or silica-based composite oxide. When the refractive index exceeds 2.7, light scattering on the particle surface increases, which is not preferable. The X-ray diffraction crystallite diameter is as described above.

Further, the titanium-based fine particles have a (310) crystal plane spacing d ¹ determined from X-ray diffraction of the fine particles in the range of 0.1440 to 0.1460 nm, preferably 0.1445 to 0.1455 nm. The (301) crystal plane spacing d ² is preferably in the range of 0.1355 to 0.1370 nm, preferably 0.1356 to 0.1368 nm.
Here, when the interplanar spacing d ¹ of the (310) crystal plane is less than 0.1440 nm, the photocatalytic activity tends to increase, and when the interplanar spacing d ^{1 of the} crystal plane exceeds 0.1460 nm, Similarly, the above-mentioned photocatalytic activity tends to increase, which is not preferable. The details of the mechanism causing such a phenomenon are not clear at the present time, but in the former case, it is considered that it is involved in the suppression of the photocatalytic reaction (310). It is considered that diffusion of (holes) to the particle surface is facilitated, and in the latter case, conversely, it is considered that it is involved in suppression of the photocatalytic reaction. Therefore, it is considered that the density of the (310) crystal plane is likely to decrease. Further, when the interplanar spacing d ² of the (301) crystal plane is less than 0.1355 nm, the photocatalytic activity tends to increase, and when the interplanar spacing d ^{2 of the} crystal plane exceeds 0.1370 nm, the same In addition, the above-described photocatalytic activity tends to increase, which is not preferable. The details of the mechanism causing such a phenomenon are not clear at this time, but, like the (310) crystal plane, it is considered that it is involved in the suppression of the photocatalytic reaction (301) The crystal plane spacing is narrowed. Therefore, it is considered that diffusion of electrons and holes to the particle surface is facilitated, and in the latter case, it is considered to be involved in the suppression of the photocatalytic reaction (301) crystal plane. This is considered to be because the (301) crystal plane density tends to decrease due to the widening of the plane spacing.

Furthermore, the titanium-based fine particles, as determined by X-ray diffraction of the fine particles, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ² ) is in the range of 9/100 to 20/100, preferably 12/100 to 14/100.
Here, when the relative peak intensity ratio (P ¹ / P ² ) is less than 9/100, the above-mentioned photocatalytic activity tends to increase, and when the relative peak intensity ratio exceeds 20/100, similarly This is not preferable because the photocatalytic activity tends to increase. The details of the mechanism causing such a phenomenon are not clear at present, but in the former case, it is considered that the (110) crystal plane is involved in the suppression of the photocatalytic reaction. This is probably because it is relatively larger than the (310) crystal plane. In the latter case, the (110) crystal plane considered to be involved in the promotion of the photocatalytic reaction is relatively less than the (310) crystal face considered to be involved in the suppression of the photocatalytic reaction. Therefore, the above-described photocatalytic activity should be suppressed, but the photocatalytic activity tends to increase on the contrary. The reason is not yet clear, but the surface position called kinks (Kink) or corners where OH groups (including free radicals such as OH) that become active sites for photocatalytic activity increase in reaction activity. It can be considered that there are relatively many.

In the present invention, silica-based oxide used for coating the titanium-based fine particles are those comprising silicon dioxide represented by the chemical formula SiO _2, it is preferably substantially made of silicon dioxide . Further, the silica-based composite oxide used in the same manner is a compound containing silicon and at least one metal element selected from zirconium, antimony, tin and aluminum, and a part of these compounds is represented by the chemical formula. If it shows typically, it will be as follows.

｜ ｜
-O-Si-O-Zr-O-
｜ ｜

｜
-O-Si-O-Al-O-
｜ ｜

｜ ｜
-O-Si-O-Sb-O-
｜ ｜

｜ ｜
-O-Si-O-Sn-O-
｜ ｜

｜ ｜ ｜
-O-Si-O-Sb-O-Zr-O-
｜ ｜ ｜

The metal oxide fine particles used in the present invention can be obtained by coating the surface of the titanium fine particles with the silica-based oxide or the silica-based composite oxide as described above.
The metal oxide fine particles are not particularly limited, but at least one silicon compound selected from silicon alkoxide and silicic acid is mixed in an aqueous dispersion containing the titanium-based fine particles, and then the silicon compound The surface of the titanium-based fine particles is preferably coated with a silica-based oxide.
Further, the metal oxide fine particles are not particularly limited, but in an aqueous dispersion containing the titanium fine particles, at least one silicon compound selected from silicon alkoxide and silicic acid, and zirconate peroxide. At least one metal compound selected from a salt, an antimonate and an aluminate is mixed, and then the silicon compound and the metal compound are hydrolyzed so that the surface of the titanium-based fine particles is made of a silica-based composite oxide. It is preferable that it is coated.
The silicon alkoxide is preferably tetramethoxysilane or a condensate thereof, or tetraethoxysilane or a condensate thereof. As the condensate of tetramethoxysilane, the general formula Si _n O _n-1 (OCH ₃ ) Methyl silicate 51 ^TM represented by _{2n + 2} and the like, and the condensate of tetraethoxysilane includes ethyl represented by the general formula Si _n O _n-1 (OC ₂ H ₅ ) _{2n + 2} Examples thereof include silicate 40 ^™ and ethyl silicate 45 ^™ .

In the metal oxide fine particles, when the weight of the titanium-based fine particles is represented by C and the weight of the coating layer is represented by S, the weight ratio (S / C) is 1/100 to 50 in terms of oxide. It is preferable that the surface of the titanium-based fine particles is coated with the silica-based oxide or the silica-based composite oxide so as to be in the range of / 100.
Here, if the weight ratio is less than 1/100 on an oxide conversion basis, the photocatalytic activity may not be sufficiently suppressed, and the weight ratio is 50/100 on an oxide conversion basis. On the other hand, the coating layer becomes thick and a desired refractive index may not be obtained.

The coating layer of the metal oxide fine particles is desired to have a refractive index that is 0.2 or more lower than the refractive index of the titanium-based fine particles, preferably 0.5 or more lower.
Here, if the refractive index of the coating layer is not lower than the refractive index of the titanium-based fine particles by 0.2 or more, light scattering on the particle surface may not be sufficiently suppressed, which is not preferable.
Further, the refractive index of the metal oxide fine particles provided with such a coating layer is desired to be in the range of 2.0 to 2.5, preferably 2.1 to 2.4.
Here, when the refractive index of the metal oxide fine particles is less than 2.0, the refractive index of the coating film obtained from the coating liquid for forming a coating film prepared using an aqueous dispersion sol containing the fine particles is 1. When the refractive index exceeds 2.5, it becomes difficult to make it 70 or more. When the refractive index exceeds 2.5, the coating film obtained from the coating liquid for forming a coating film prepared using an aqueous dispersion sol containing fine particles has a sufficient hardness ( That is, if an amount necessary for providing an appropriate hard coat property) is added, the refractive index of the coating film becomes excessively high and interference fringes are easily generated, which is not preferable.

The water-dispersed sol containing the metal oxide fine particles contains 1 to 30% by weight, preferably 5 to 20% by weight of the metal oxide fine particles, and has a turbidity of 0.1 to 10.0 cm ⁻¹ . Preferably, it is desired to be in the range of 0.2 to 8.0 cm ⁻¹ .
Here, when the content of the metal oxide fine particles is less than 1% by weight, not only the reactivity with the surface treatment agent is deteriorated, but also the amount of solvent used for solvent substitution is increased, which is economical. If the content exceeds 30% by weight, viscosity increases and the stability of the water-dispersed sol deteriorates, which is not preferable. Furthermore, it is difficult to obtain a turbidity of the water-dispersed sol of less than 0.1 cm ⁻¹ , and when the turbidity exceeds 10.0 cm ⁻¹ , a coating film prepared using the water-dispersed sol Since the transparency of the coating film obtained from the coating solution for forming may be significantly lowered, it is not preferable.

[Organic solvent dispersion sol of high refractive index metal oxide fine particles]
The organic solvent dispersion sol of the high refractive index metal oxide fine particles according to the present invention is obtained by dispersing the high refractive index metal oxide fine particles contained in the water dispersion sol in an organic solvent.
In the present invention, the content of the metal oxide fine particles varies depending on the type of organic solvent used and its use, but for example, when used for an optical substrate, the total amount of the organic solvent-dispersed sol is used. It is preferable to be in the range of 10 to 40% by weight, preferably 20 to 30% by weight.
Here, if the content of the metal oxide fine particles is less than 10% by weight, the solid content of the coating liquid for optical substrates and the like using this as a raw material decreases, so the film thickness of the coating film becomes thin. Therefore, the film hardness may be lowered, which is not preferable. On the other hand, when the content exceeds 40% by weight, the stability of the organic solvent-dispersed sol is deteriorated, which is not preferable.

As the organic solvent varies depending its intended use, methanol, ethanol, butanol, propanol, or ethylene glycol monomethyl ether and isopropyl alcohol, propylene glycol monomethyl ether, propylene glycol monoethyl It is preferable to use it selected from organic compounds such as ethers such as ether and ketones such as methyl ethyl ketone and γ-butyrolactone. Among these, when used for optical substrate applications, it is preferable to use at least one organic compound selected from alcohols such as methanol and ethers such as propylene glycol monomethyl ether. The reason is that the drying speed of the coating film is relatively fast and it is easy to form a film.
The organic solvent-dispersed sol according to the present invention is obtained by subjecting the water-dispersed sol of the above-described high refractive index metal oxide fine particles to a solvent substitution device and substituting water contained in the water-dispersed sol with an organic solvent. It is preferable that

[Preparation method]
The preparation method of the high-refractive-index metal oxide fine particle water-dispersed sol and organic solvent-dispersed sol according to the present invention is as follows. However, since the preparation method described here shows one embodiment, the water-dispersed sol and the organic solvent-dispersed sol according to the present invention are not limited to those obtained from these preparation methods. The pure water used in the present invention refers to ion-exchanged water, and ultrapure water is obtained by further removing impurities contained in pure water, and the content of impurities is 0.01 μg / L or less. I mean.

(1) Preparation method of water-dispersed sol
Preparation method-1
The first water-dispersed sol preparation method (hereinafter referred to as “preparation method-1”) according to the present invention is as follows.
A method for preparing an aqueous dispersion sol containing high refractive index metal oxide fine particles obtained by coating the surface of titanium fine particles having an average particle diameter of 15 to 60 nm measured by a dynamic light scattering method with at least a silica-based oxide. There,
(A) A mixed aqueous solution containing peroxytitanic acid and potassium stannate and / or silicon compound is placed in an autoclave and hydrothermally treated at a temperature of 150 to 250 ° C. to contain titanium and tin and / or silicon. Producing a composite oxide;
(B) A step of obtaining composite oxide particles having an average particle diameter of 1 to 80 μm containing titanium and tin and / or silicon by drying and granulating the composite oxide produced in the step (a). ,
(C) a step of firing the composite oxide particles obtained in the step (b) at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain titanium-based particles composed of a fired product of the composite oxide particles;
(D) The titanium-based particles obtained in the step (c) are pulverized to form titanium-based fine particles having an average particle diameter of 15 to 60 nm as measured by a dynamic light scattering method. Obtaining a water-dispersed sol dispersed in water or ultrapure water;
(E) If necessary, subject the aqueous dispersion obtained in the step (d) to a wet classifier to separate and remove at least coarse particles having a particle diameter of 100 nm or more as measured by a dynamic light scattering method. And (f) mixing at least one silicon compound selected from (i) silicon alkoxide and silicic acid into the aqueous dispersion obtained in the step (d) or the step (e), The method includes a step of obtaining an aqueous dispersion sol containing metal oxide fine particles obtained by hydrolyzing a silicon compound and coating the surface of the titanium fine particles with a silica-based oxide.
Next, these steps will be described in more detail as follows.

Step (a)
A white solution having a pH of about 9 to 10 is prepared by mixing an aqueous solution of titanium tetrachloride containing about 7 to 8% by weight of titanium tetrachloride on a TiO ₂ basis and an aqueous ammonia containing about 10 to 20% by weight of ammonia (NH ₃ ). A slurry liquid is obtained. The slurry is then filtered and washed with pure water to obtain a hydrous titanate cake having a solid content of about 8 to 14% by weight.
Next, after adding hydrogen peroxide water containing about 30 to 40% by weight of hydrogen peroxide (H ₂ O ₂ ) and pure water to this cake, the temperature is about 70 to 90 ° C. The mixture is heated for 5 hours with stirring to obtain an aqueous solution of titanic acid peroxide containing about 1 to 3% by weight of titanic acid peroxide on a TiO ₂ basis. This aqueous solution of titanic acid peroxide is transparent yellowish brown and has a pH of about 7.5 to 8.5.
However, in the present invention, peroxytitanic acid prepared by other methods may be used.

Next, a cation exchange resin is mixed with the aqueous solution of titanic acid titanate, and an aqueous potassium stannate solution containing about 0.5 to 2% by weight of potassium stannate in terms of SnO ₂ is gradually added thereto with stirring. To do.
Next, after separating the cation exchange resin incorporating potassium ions and the like, silica sol containing about 10 to 20% by weight of silicon oxide (SiO ₂ ) containing silica fine particles having an average particle diameter of about 4 to 12 nm and pure water. And hydrothermally treated in an autoclave at a temperature of 150 to 250 ° C., preferably 160 to 200 ° C. for about 15 to 20 hours, preferably 16 to 19 hours. In this case, silicon alkoxide made of silicic acid, tetramethoxysilane, tetraethoxysilane, or a condensate thereof can be used instead of the silica sol. However, when preparing composite oxide particles composed of titanium and tin, it is not necessary to mix these silica sources.

Here, when the hydrothermal treatment temperature is less than 150 ° C., as described above, crystallization of a composite oxide containing titanium and tin and / or silicon is difficult to proceed. When the hydrothermal treatment temperature exceeds 250 ° C., the crystallization of the composite oxide proceeds excessively, and the resulting particles tend to aggregate. Hydrothermal treatment is preferably performed at a selected temperature. Furthermore, if the hydrothermal treatment time is less than 15 hours, composite oxide fine particles that are not crystallized or composite oxide fine particles that are not crystallized may remain, and if the hydrothermal treatment time exceeds 20 hours, This is not preferable because the generated crystalline composite oxide fine particles tend to aggregate.

As a result, a mixed aqueous solution containing a composite oxide containing titanium, tin, and silicon having a rutile-type crystal structure is obtained. However, when the silica source is not mixed, a mixed aqueous solution containing a composite oxide containing titanium and tin is obtained, but description thereof will be omitted below.
Next, after cooling the obtained mixed aqueous solution to room temperature, it is subjected to an ultrafiltration membrane device and concentrated to obtain a mixed aqueous solution having a solid content concentration of about 2 to 15% by weight. Next, the pH of the mixed aqueous solution is adjusted to 3 to 10, preferably 4 to 8, as necessary. This pH adjustment can be performed by adding a cation exchange resin to the mixed aqueous solution and removing potassium ions and the like contained in the mixed aqueous solution when the mixed aqueous solution exhibits an alkalinity of pH 10 or higher. it can. On the other hand, the mixed aqueous solution hardly has a pH of less than 3, but in such a case, it can be carried out by adding potassium hydroxide or the like.

Here, when the pH is less than 3, as described above, not only the concern about equipment corrosion increases, but also the storage stability of the mixed aqueous solution tends to decrease, and when the pH exceeds 10. Since the capillary tension acting between the particles during drying is increased and it becomes easy to form a hard dry powder (that is, a dry powder that is difficult to be pulverized in the subsequent pulverization step), the pH range is adjusted appropriately. Is preferred.
Then separated and the cation exchange resin used for the pH adjustment, the solid content concentration to obtain a mixed aqueous solution of about 2-15 by weight%. However, when the pH of the mixed aqueous solution is in the range of 3 to 10, it is not necessary to perform the above pH adjustment, so that separation / removal of the cation exchange resin or the like is not required.

Step (b)
Next, the composite oxide contained in the mixed aqueous solution is dried to form particles. In this case, after the mixed aqueous solution is subjected to a general hot air drying apparatus to dry the composite oxide contained in the mixed aqueous solution, it is obtained as a dried body (usually obtained as a massive solid). Although it can be prepared by subjecting it to a pulverizer and appropriately pulverizing it, the operation is complicated. Therefore, it is preferable to spray-dry the mixed aqueous solution using a spray dryer. In addition, if this spray dryer is used, the said solid content can be dried and granulated simultaneously.
As the spray dryer, a conventionally known one (disk spray type or nozzle type spray dryer) can be used. Moreover, this spray drying is performed by spraying the aqueous dispersion concentrated as necessary into a hot air stream using a conventionally known method.

At this time, the temperature of the hot air is desirably such that the inlet temperature is in the range of 150 to 200 ° C, preferably 170 to 180 ° C, and the outlet temperature is in the range of 40 to 60 ° C. Here, if the inlet temperature is less than 150 ° C., the solid content is insufficiently dried, and if it exceeds 200 ° C., it is not economical. Further, if the outlet temperature is less than 40 ° C., the degree of drying of the powder is poor and adheres to the inside of the apparatus, which is not preferable.
As a result, dried composite oxide particles having an average particle diameter of 1 to 80 μm, preferably 2 to 60 μm are obtained.
As described above, the drying operation can be performed using a general hot-air drying apparatus. However, since the dried body obtained from the drying becomes a lump-like solid, it is pulverized by using a pulverizing apparatus. Even so, it is not easy to efficiently obtain particles having a uniform particle diameter.

Step (c)
Next, the spray-dried composite oxide particles are subjected to a calcining apparatus, and the temperature is 300 to 800 ° C., preferably 400 to 700 ° C. in an oxygen-containing atmosphere such as air, preferably 30 to 240 minutes, preferably Bake for 60-180 minutes.
Here, when the firing temperature is less than 300 ° C., as described above, since crystallization within the particles is difficult to proceed, it becomes difficult to obtain particles having a desired X-ray diffraction crystallite diameter. In addition, when the temperature exceeds 800 ° C., the sintering of the particles (especially, the sintering of the primary particles) proceeds rapidly, and as a result, the specific surface area on the particle surface is significantly reduced. It is preferable to fire at a temperature appropriately selected from the above. Furthermore, if the firing time is less than 30 minutes, the entire composite oxide particle may not be fired sufficiently, and if the firing time exceeds 240 minutes, it is not preferable because it is not economical.

Thereby, composite oxide particles having an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm, preferably 8.0 to 12.0 nm, that is, titanium-based particles having a relatively high degree of crystallinity are obtained. More specifically, since the degree of crystallization of the composite oxide particles increases when the firing operation is performed, crystalline titanium having the X-ray diffraction crystallite diameter and having a rutile crystal structure. System particles can be obtained. Further, the titanium-based particles themselves have a high refractive index and a low photocatalytic activity.
Here, when the X-ray diffraction crystallite diameter of less than 7.5 nm is obtained, it is necessary to increase the firing temperature, and the crystallite diameter exceeds 14.0 nm. Therefore, it is necessary to lower the firing temperature.

Step (d)
Next, the calcined titanium-based particles are particles having a relatively large particle size with an average particle size of 1 to 80 μm. Therefore, the particles are subjected to a pulverizer and have a particle size that is small enough to make a sol. Grind into.
As this pulverizer, a conventionally known pulverizer such as a sand mill, a roll mill, a bead mill, an ultrasonic disperser, an optimizer, a nanomizer (registered trademark or trademark), and the like can be used. The operating conditions of the pulverizer vary depending on the pulverizer to be used and the properties of the titanium-based fine particles. For example, when using a sand mill (a tabletop sand mill manufactured by Kansai Paint Co., Ltd.), a ceramic disk rotor, etc. in an apparatus fitted, putting an aqueous solution suspended spherical silica beads of particle size 0.1~0.2mm the titanium-containing particles (solid content concentration of 5 to 40 wt%), general conditions It is preferable to perform the pulverization process under a lower position (for example, a rotor rotational speed of 600 to 2000 rpm, a processing time of 1 to 10 hours, etc.).

Thereby, titanium-based fine particles (that is, crystalline titanium-based fine particles) having an average particle diameter of 15 to 60 nm as measured by a dynamic light scattering method are obtained.
Here, when the average particle diameter is less than 15 nm, as described above, when the titanium-based fine particles are dispersed at a high concentration in an aqueous solution (water-dispersed sol), the viscosity of the sol is remarkably increased. If the average particle diameter exceeds 60 nm, light scattering on the particle surface increases, and as a result, the turbidity of the water-dispersed sol containing metal oxide fine particles obtained using the fine particles increases. Therefore, it is preferable to adjust appropriately so as to be within the above range.

Further, the titanium-based fine particles thus obtained are crystalline fine particles having a rutile-type crystal structure, and are 7.5 to 14.0 nm, preferably 8.0 to 12.0 nm. It has a child diameter and a specific surface area of 70 to 155 m ² / g, preferably 90 to 130 m ² / g, and its refractive index is in the range of 2.2 to 2.7, preferably 2.3 to 2.6. It is what.
Here, when the specific surface area is less than 70 m ² / g, it is necessary to lower the firing temperature, and when the specific surface area exceeds 155 m ² / g, It is necessary to increase the firing temperature. Furthermore, when the refractive index is less than 2.2, it is necessary to increase the firing temperature. When the refractive index is greater than 2.7, the firing is performed. The temperature needs to be lowered. The X-ray diffraction crystallite diameter is as described above.

Step (e)
However, since the titanium-based fine particles are produced by pulverization, pulverization, and peptization in this way, coarse particles having a relatively large particle diameter may be included in the particle group. Therefore, when such coarse particles are included, when the titanium-based fine particles are dispersed in pure water or ultrapure water, the aqueous dispersion is subjected to a wet classifier and measured by a dynamic light scattering method. It is necessary to separate and remove at least coarse particles having a particle diameter of 100 nm or more. However, this operation is not necessarily performed when such coarse particles are not included.
As this wet classifier, a conventionally known centrifuge, hydrocyclone, chickenpox (natural sedimentation device), or the like can be used.

For the separation and removal of the coarse particles, the distribution frequency of coarse particles having a particle diameter of 100 nm or more is preferably 1% or less in the particle diameter frequency distribution when the obtained titanium-based fine particles are measured by a dynamic light scattering method. Is preferably 0.2% or less.
Here, when the distribution frequency of the coarse particles exceeds 1%, as described above, the water-dispersed sol containing metal oxide fine particles obtained from titanium-based fine particles containing such coarse particles is 10 cm ^−1. The transparency of the coating film obtained from the coating liquid for forming a coating film prepared by using the water-dispersed sol may be reduced. It is desirable to separate and remove such coarse particles as much as possible.
Thereby, titanium-based fine particles (that is, crystalline titanium-based fine particles) having an average particle diameter of 15 to 60 nm, preferably 15 to 45 nm, as measured by a dynamic light scattering method are obtained.
In addition, since the aqueous dispersion obtained by dispersing the pulverized titanium-based fine particles in pure water or ultrapure water contains not a few potassium ions and the like, before supplying them to the wet classifier, It is desirable to remove it using a cation exchange resin.

Step (f)
Next, the surface of the titanium-based fine particles is applied to a dispersion obtained by separating and removing the coarse particles, that is, an aqueous dispersion sol containing titanium-based fine particles having an average particle diameter of 15 to 60 nm as measured by a dynamic light scattering method. A raw material compound for coating with a silica-based oxide is added.
That is, when the surface of the titanium-based fine particles is coated with a silica-based oxide, at least one silicon compound selected from silicon alkoxide and silicic acid is added to the water-dispersed sol. Next, when the silicon compound is hydrolyzed, the surface of the titanium-based fine particles is coated with a silica-based oxide such as silicon dioxide.
Here, as described above, the silicon alkoxide is preferably tetramethoxysilane or a condensate thereof, or tetraethoxysilane or a condensate thereof.

Thereby, the metal oxide fine particle by which the surface of the said titanium type fine particle was coat | covered with the silica type oxide is obtained.
In the metal oxide fine particles, when the weight of the titanium-based fine particles is represented by C and the weight of the coating layer is represented by S, the weight ratio (S / C) is 1/100 to 50 in terms of oxide. It is preferable to coat the silica-based oxide on the surface of the titanium-based fine particles so as to be in the range of / 100, preferably 5/100 to 30/100.
Here, if the weight ratio is less than 1/100 in terms of oxide, as described above, the photocatalytic activity may not be sufficiently suppressed, and the weight ratio may be oxidized. When it exceeds 50/100 on the basis of physical conversion, the coating layer becomes thick and a desired refractive index may not be obtained, which is not preferable.

In addition, since the coating amount depends on the amount of the raw material compound added to the water-dispersed sol, the amount of the raw material compound is preferably selected appropriately.
In addition, the coating layer formed in this manner is desired to have a refractive index lower by 0.2 or more than the refractive index of the titanium-based fine particles, but the refractive index of a silica-based oxide such as silicon dioxide. Is around 1.45, so this condition can be easily satisfied.
Thus, by coating the surface of the titanium-based fine particles with the silica-based oxide, light scattering on the particle surface can be greatly suppressed. Thereby, the turbidity of the water-dispersed sol described below can be kept low.

Further, the refractive index of the metal oxide fine particles obtained in this way is such that the thickness of the coating layer is 5 nm or less, more specifically about 0.1 to 3 nm (however, detailed values cannot be measured). Therefore, the refractive index of the titanium-based fine particles is almost the same. That is, the refractive index is relatively high, 2.0 to 2.5, preferably 2.1 to 2.4.
Here, when the metal oxide fine particles having a refractive index of less than 2.0 are obtained, it is difficult to form a desired high refractive index coating film (for example, a coating film for an optical substrate). Therefore, it is necessary to make the thickness of the coating layer thinner. In addition, when the metal oxide fine particles having a refractive index of more than 2.5 can be obtained, it may be difficult to suppress light scattering on the particle surface. There is a need to.

  In the water-dispersed sol thus obtained, ionized substances added or by-produced in the above preparation process, for example, cationic substances such as potassium ions, sodium ions, ammonium ions, tin ions, titanium ions, and chloride ions , Sulfate ions, nitrate ions, silicate ions, stannate ions, titanate ions and the like. Therefore, it is desirable to remove as much of the ionized substance as possible by adding an anion exchange resin or a cation exchange resin to the water-dispersed sol as necessary and stirring for an appropriate time. In addition, although the standard which removes the said ionization substance beforehand changes with use applications of the said water dispersion sol, it is performed until the total ion concentration of the said ionization substance contained in this water dispersion sol becomes 0.1 mol / L or less. It is preferable. Here, it is not preferable that the total ion concentration exceeds 0.1 mol / L, because aggregation tends to occur when dispersed in an organic solvent.

Preparation method-2
The method for preparing the second water-dispersed sol according to the present invention (hereinafter referred to as “Preparation Method-2”) is as follows.
Method for preparing water-dispersed sol containing high refractive index metal oxide fine particles obtained by coating the surface of titanium fine particles having an average particle diameter of 15 to 60 nm measured by dynamic light scattering method with at least silica-based composite oxide Because
(A) A mixed aqueous solution containing peroxytitanic acid and potassium stannate and / or silicon compound is placed in an autoclave and hydrothermally treated at a temperature of 150 to 250 ° C. to contain titanium and tin and / or silicon. Producing a composite oxide;
(B) A step of obtaining composite oxide particles having an average particle diameter of 1 to 80 μm containing titanium and tin and / or silicon by drying and granulating the composite oxide produced in the step (a). ,
(C) a step of firing the composite oxide particles obtained in the step (b) at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain titanium-based particles composed of a fired product of the composite oxide particles;
(D) The titanium-based particles obtained in the step (c) are pulverized to form titanium-based fine particles having an average particle diameter of 15 to 60 nm as measured by a dynamic light scattering method. Obtaining a water-dispersed sol dispersed in water or ultrapure water;
(E) If necessary, subject the aqueous dispersion obtained in the step (d) to a wet classifier to separate and remove at least coarse particles having a particle diameter of 100 nm or more as measured by a dynamic light scattering method. And (f) in the aqueous dispersion obtained in the step (d) or the step (e), (i) at least one silicon compound selected from silicon alkoxide and silicic acid, and zirconic peroxide At least one metal compound selected from a salt, antimonate, stannate and aluminate is mixed, and the surface of the titanium-based fine particles is silica-based by hydrolyzing the silicon compound and the metal compound. The method includes a step of obtaining an aqueous dispersion sol containing metal oxide fine particles coated with a composite oxide.
That is, the difference between this preparation method-2 and the above preparation method-1 is only the operating conditions of the step (f). Therefore, only the step (f) will be described here.

Steps (a) to (e)
As described in Preparation Method-1.
Step (f)
The dispersion liquid obtained by separating and removing coarse particles in the step (e), that is, an aqueous dispersion sol containing titanium fine particles having an average particle diameter of 15 to 60 nm when measured by a dynamic light scattering method is used. A raw material compound for coating the surface with a silica-based composite oxide is added.
That is, when the surface of the titanium-based fine particles is coated with a silica-based composite oxide, the water-dispersed sol is mixed with at least one silicon compound selected from silicon alkoxide and silicic acid, zirconate peroxide, antimony At least one metal compound selected from acid salts, stannates and aluminates is added. Next, when the silicon compound and the metal compound are hydrolyzed, the surface of the titanium-based fine particles contains silica and at least one metal element selected from zirconium, antimony, tin and aluminum. Covered with objects.
Here, as described above, the silicon alkoxide is preferably tetramethoxysilane or a condensate thereof, or tetraethoxysilane or a condensate thereof.

Thereby, the metal oxide fine particle by which the surface of the said titanium type fine particle was coat | covered with the silica type complex oxide is obtained.
In the metal oxide fine particles, when the weight of the titanium-based fine particles is represented by C and the weight of the coating layer is represented by S, the weight ratio (S / C) is 1/100 to 50 in terms of oxide. It is preferable to coat the silica-based composite oxide on the surface of the titanium-based fine particles so as to be in the range of / 100, preferably 5/100 to 30/100.
Here, if the weight ratio is less than 1/100 in terms of oxide, as described above, the photocatalytic activity may not be sufficiently suppressed, and the weight ratio may be oxidized. When it exceeds 50/100 on the basis of physical conversion, the coating layer becomes thick and a desired refractive index may not be obtained, which is not preferable.

In addition, since the coating amount depends on the amount of the raw material compound added to the water-dispersed sol, the amount of the raw material compound is preferably selected appropriately.
That is, the refractive index of the silica-based composite oxide containing silicon and zirconium, antimony, tin and / or aluminum metal elements depends on the content of these metal elements. It is desirable to adjust and add the amount of zirconate oxide, antimonate, stannate, aluminate and the like. However, since the refractive index of the titanium-based fine particles is as high as 2.2 to 2.7, it is very easy to form a coating layer having a refractive index lower by 0.2 or more.
Thus, by coating the surface of the titanium-based fine particles with the silica-based composite oxide, light scattering on the particle surface can be greatly suppressed. Thereby, the turbidity of the water-dispersed sol described below can be kept low.

Further, the refractive index of the metal oxide fine particles obtained in this way is such that the thickness of the coating layer is 5 nm or less, more specifically about 0.1 to 3 nm (however, detailed values cannot be measured). Therefore, the refractive index of the titanium-based fine particles is almost the same. That is, the refractive index is relatively high, 2.0 to 2.5, preferably 2.1 to 2.4.
Here, when a metal oxide fine particle having a refractive index of less than 2.0 is obtained, the coating film having a desired high refractive index (for example, for an optical substrate), as in Preparation Method-1. Therefore, it is necessary to make the coating layer thinner. In addition, when the metal oxide fine particles having a refractive index of more than 2.5 can be obtained, it may be difficult to suppress light scattering on the particle surface. There is a need to.
Ionized substances added or by-produced in the above-described preparation process in the aqueous dispersion sol thus obtained, for example, cationic substances such as potassium ions, sodium ions, ammonium ions, tin ions, titanium ions, chloride ions, Anionic substances such as sulfate ion, nitrate ion, silicate ion, stannate ion and titanate ion are included. Therefore, it is desirable to remove the ionized substance in advance as in Preparation Method-1.

The water-dispersed sol containing the metal oxide fine particles obtained by the above preparation method-1 and preparation method-2 contains 1-30 wt%, preferably 5-20 wt% of the metal oxide fine particles, and further its turbidity. Is in the range of 0.1 to 10.0 cm ⁻¹ , preferably 0.2 to 8.0 cm ⁻¹ .
Here, the content of the metal oxide fine particles is almost determined by the amount added when the pulverized titanium-based fine particles are dispersed in pure water or ultrapure water. When the content exceeds 30% by weight, Since the rise of the water dispersion sol deteriorates due to an increase or the like, it is preferable to adjust appropriately within the above range.
On the other hand, the turbidity of the water-dispersed sol is almost determined by the light scattering rate and the content of the metal oxide fine particles, but it is difficult to obtain a turbidity of less than 0.1 cm ⁻¹ , and the turbidity When the degree exceeds 10.0 cm ⁻¹ , the transparency of the coating film obtained from the coating liquid for forming a coating film prepared using the water-dispersed sol may be remarkably lowered, which is not preferable.

Thus, when the turbidity of the water-dispersed sol exceeds 10.0 cm ⁻¹ , it is necessary to slightly increase the thickness of the coating layer in order to suppress the light scattering rate on the surface of the metal oxide fine particles. is there. In addition, since this problem can sometimes be solved by reducing the average particle size of the metal oxide fine particles, in some cases, the average particle size of the titanium-based fine particles obtained by pulverizing the titanium-based particles is reduced. Alternatively, it is desirable to remove as much as possible coarse particles contained in the titanium-based fine particles in the subsequent wet classification step.
In this way, a water-dispersed sol of high refractive index metal oxide fine particles according to the present invention is obtained.

(2) Preparation method of organic solvent dispersion sol
Surface treatment of metal oxide fine particles The water-dispersed sol of the high refractive index metal oxide fine particles obtained above is subjected to a solvent displacement device to replace the water contained in the water-dispersed sol with an organic solvent. Thus, an organic solvent-dispersed sol of high refractive index metal oxide fine particles is prepared.
However, since the high-refractive-index metal oxide fine particles contained in the water-dispersed sol are hydrophilic fine particles, it is desirable to make them into hydrophobic fine particles in advance. For this purpose, it is preferable to treat the surface of the fine particles by a conventionally known method using a surface treating agent.
The surface treatment agent is not particularly limited, and examples thereof include an organosilicon compound and an amine compound.
Here, as the organosilicon compound, a conventionally known silane coupling agent having a hydrolyzable group can be used, and the type thereof is appropriately selected according to the use, the type of solvent, and the like. These silane coupling agents may be used alone or in combination of two or more. Furthermore, specific examples of the organosilicon compound are as shown in the following (a) to (d).

(A) a monofunctional silane represented by the general formula R ₃ SiX (wherein R represents an organic group having an alkyl group, a phenyl group, a vinyl group, a methacryloxy group, a mercapto group, an amino group or an epoxy group; X represents a hydrolyzable group such as an alkoxy group or a chloro group.)
Typical examples include trimethylethoxysilane, dimethylphenylethoxysilane, dimethylvinylethoxysilane, and the like.
(B) Bifunctional silane represented by the general formula R ₂ SiX ₂ (wherein R and X are as described above).
Representative examples include dimethyldiethoxysilane, diphenyldiethoxysilane, and the like.

(C) Trifunctional silane represented by the general formula RSiX ₃ (wherein R and X are as described above).
Typical examples include methyltriethoxysilane and phenyltriethoxysilane.
(D) Tetrafunctional silane represented by the general formula SiX ₄ (wherein X is as described above).
Typical examples include tetraalkoxysilanes such as tetramethoxysilane and tetraethoxysilane.

Examples of the amine compound include ammonia; alkylamines such as ethylamine, triethylamine, isopropylamine and n-propylamine; aralkylamines such as benzylamine; alicyclic amines such as piperidine; monoethanolamine; And quaternary ammonium salts such as alkanolamine, tetramethylammonium salt, and tetramethylammonium hydroxide.

The surface treatment of the high refractive index metal oxide fine particles is not particularly limited. For example, when the organosilicon compound is used as a surface treatment agent, the organosilicon compound dissolved in an organic solvent such as methanol or the like After the partial hydrolyzate is added to the water-dispersed sol, it is heated to a temperature of about 40 to 60 ° C. and stirred for about 1 to 20 hours to hydrolyze the organosilicon compound or the partial hydrolyzate thereof. Can be done.
In the stage where the surface treatment operation is completed, all of the hydrolyzable groups of the organosilicon compound have reacted with OH groups present on the surface of the coating layer of the high refractive index metal oxide fine particles. However, it may be in a state in which a part thereof remains unreacted.

Solvent replacement of water-dispersed sol The water-dispersed sol containing the high-refractive-index metal oxide fine particles that have been surface-treated as described above is subjected to a solvent replacement device, and water contained in the water-dispersed sol is replaced with an organic solvent.
As this solvent replacement device, a conventionally known solvent replacement device such as an ultrafiltration device or a rotary evaporator can be used. The operating conditions of the solvent displacement device vary depending on the solvent displacement device used, the type of the organic solvent, and the like. For example, when using an ultrafiltration device (SIP-1013 manufactured by Asahi Kasei Co., Ltd.) The water-dispersed sol (solid content concentration: 1 to 30% by weight) and an organic solvent (for example, methanol) to be replaced with water contained in the sol are fed into the apparatus equipped with a filtration membrane, It is preferable to perform solvent replacement under such conditions (for example, pump discharge pressure of 10 to 20 MPa, water content after solvent replacement of 0.1 to 5% by weight, etc.).
In this case, when the concentration of the high refractive index metal oxide fine particles contained in the water-dispersed sol is much lower than the desired solid content concentration of the organic solvent-dispersed sol, the water-dispersed sol is subjected to ultrafiltration. It is preferable to use the above-described solvent replacement step after increasing the solid content concentration of the water-dispersed sol by concentrating using a solvent.

The organic solvent, as described above, methanol, ethanol, butanol, propanol, alcohols such as isopropyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether And organic compounds selected from ketones such as ethers such as methyl ethyl ketone and γ-butyrolactone. Among these, when the organic solvent-dispersed sol is used for preparing a coating solution for an optical substrate, at least one organic compound selected from alcohols such as methanol and ethers such as propylene glycol monomethyl ether is used. It is preferable. The reason is that the drying speed of the coating film is relatively fast and it is easy to form a film.

Preparation of organic solvent dispersion sol The solid content concentration of the organic solvent dispersion sol thus obtained, that is, the content of the high refractive index metal oxide fine particles, the usage of the organic solvent dispersion sol, the type of the organic solvent, etc. Depending on the total amount of the dispersion sol, for example, when used for an optical substrate, it is preferably adjusted to be in the range of 10 to 40% by weight, preferably 20 to 30% by weight.
Here, if the content of the metal oxide fine particles is less than 10% by weight, the coating content having a predetermined film thickness and film hardness is low because the solid content is small, such as a coating solution for an optical base material using this as a raw material. It is difficult to economically form a film, and when the content exceeds 40% by weight, the stability of the organic solvent-dispersed sol is deteriorated, which is not preferable.
Thus, the organic solvent dispersion sol of the high refractive index metal oxide fine particles according to the present invention is obtained.

  Next, an optical substrate coating solution prepared using the organic solvent-dispersed sol of high refractive index metal oxide fine particles according to the present invention and an optical substrate coating film obtained by applying the coating solution will be described. Is as follows. However, since the dispersion sol of the high refractive index metal oxide fine particles according to the present invention, that is, the water dispersion sol and the organic dispersion sol can be used for other applications, the dispersion sol of the present invention is limited to these applications. Is not to be done.

[Coating liquid for optical substrate]
Coating liquid A for optical substrates
As a typical example of the coating liquid for an optical substrate, there is a coating liquid for forming a hard coat layer film (hereinafter referred to as “optical substrate coating liquid A”).
The coating liquid A for optical substrates is generally prepared by mixing an organic solvent dispersion sol containing metal oxide fine particles and an organosilicon compound (that is, a vehicle component) as a binder component. A representative example of a composition obtained by mixing the organic solvent-dispersed sol and the organosilicon compound is as follows.

That is, the coating liquid A for an optical substrate prepared using the organic solvent-dispersed sol is
(1) Metal oxide fine particles obtained by coating the surface of titanium fine particles having an average particle diameter of 15 to 60 nm measured by a dynamic light scattering method with at least a silica-based oxide or a silica-based composite oxide, ) The titanium-based fine particles are crystalline fine particles having a rutile-type crystal structure, and have an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm and a specific surface area of 70 to 155 m ² / g, Further, the refractive index is in the range of 2.2 to 2.7, and (b) the coating layer has a refractive index lower by 0.2 or more than the refractive index of the titanium-based fine particles, and the coating layer is provided. High refractive index metal oxide fine particles having a refractive index in the range of 2.0 to 2.5, and (2) an organosilicon compound represented by the following general formula (I) and / or The hydrolyzate is included.
R ¹ _a R ² _b Si (OR ³ ) _{4- (a + b)} (I)
(In the formula, R ¹ is an alkyl group having 1 to 6 carbon atoms, an organic group having 8 or less carbon atoms containing a vinyl group, an organic group having 8 or less carbon atoms containing an epoxy group, and 8 carbon atoms containing a methacryloxy group. The following organic group, an organic group having 1 to 5 carbon atoms containing a mercapto group or an organic group having 1 to 5 carbon atoms containing an amino group, R ² is an alkyl group having 1 to 3 carbon atoms, an alkylene group, A cycloalkyl group, a halogenated alkyl group or an allyl group, R ³ is an alkyl group having 1 to ³ carbon atoms, an alkylene group or a cycloalkyl group, a is an integer of 0 or 1, b is 0, 1 Or an integer of 2.)

  As the organosilicon compound represented by the general formula (I), an alkoxysilane compound is exemplified as a typical example, and specific examples thereof include tetraethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, and γ-methacryloxy. Propyltrimethoxysilane, trimethylchlorosilane, α-glycidoxymethyltrimethoxysilane, α-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ- Glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, β- (3 4-epoxycyclohexyl) Ethyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) -γ-aminopropyl Examples include methyldietoxylan. Among these, tetraethoxysilane, methyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, etc. Is preferably used. Moreover, these organosilicon compounds (2) may use not only one type but also two or more types.

  In preparing the coating liquid A for an optical substrate, the organosilicon compound is partially hydrolyzed or hydrolyzed in the absence of a solvent or in a polar organic solvent such as alcohol in the presence of an acid and water. It is preferable to mix with the organic solvent dispersion sol. However, the organosilicon compound may be partially hydrolyzed or hydrolyzed after mixing with the organic solvent-dispersed sol.

In order to improve the dyeability of the hard coat layer film, the adhesion to the plastic lens substrate, etc., and to prevent the occurrence of cracks, the coating liquid A for the optical substrate, in addition to the above components, An uncrosslinked epoxy compound may be contained.
Examples of the uncrosslinked epoxy compound include 1,6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, and the like. Among these, it is preferable to use 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, or the like. These uncrosslinked epoxy compounds may be used not only in one kind but also in two kinds or more.
Furthermore, the coating liquid A for the optical substrate is composed of components other than those described above, such as surfactants, leveling agents or ultraviolet absorbers, and further, Patent Document 2, Patent Document 3, JP-A-11-310755, and International Publication An organic compound or an inorganic compound described in a conventionally known document such as WO2007 / 046357 may be included.

Coating liquid B for optical substrates
Furthermore, as a typical example of the coating liquid for an optical substrate, there is a primer layer film forming coating liquid (hereinafter referred to as “optical substrate coating liquid B”).
This coating liquid B for optical substrates is generally prepared by mixing an organic solvent-dispersed sol containing metal oxide fine particles and a thermosetting resin or thermoplastic resin (that is, a resin component) as a binder component. However, a representative example of a composition obtained by mixing the organic solvent-dispersed sol and the resin component according to the present invention is as follows.

That is, the coating liquid B for an optical substrate prepared using the organic solvent-dispersed sol is
(1) Metal oxide fine particles obtained by coating the surface of titanium fine particles having an average particle diameter of 15 to 60 nm measured by a dynamic light scattering method with at least a silica-based oxide or a silica-based composite oxide, ) The titanium-based fine particles are crystalline fine particles having a rutile-type crystal structure, and have an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm and a specific surface area of 70 to 155 m ² / g, Further, the refractive index is in the range of 2.2 to 2.7, and (b) the coating layer has a refractive index lower by 0.2 or more than the refractive index of the titanium-based fine particles, and the coating layer is provided And a high refractive index metal oxide fine particle having a refractive index in the range of 2.0 to 2.5, and (2) a thermosetting resin or a thermoplastic resin.

Examples of the thermosetting resin include urethane resins, epoxy resins, and melamine resins. Among these, it is preferable to use a urethane resin, an epoxy resin, or the like.
More specifically, examples of the urethane resin include a reaction product of a block-type polyisocyanate such as hexamethylene diisocyanate and an active hydrogen-containing compound such as polyester polyol and polyether polyol, and the epoxy resin. Examples of the resin include a polyalkylene ether-modified epoxy resin and an epoxy group-containing compound in which a flexible skeleton (soft segment) is introduced into a molecular chain. Further, examples of the melamine-based resin include a cured product of etherified methylol melamine, a polyester polyol, and a polyether polyol. Among these, it is preferable to use a urethane-based resin that is a cured product of a block type isocyanate and a polyol. Further, these thermosetting resins may be used not only in one type but also in two or more types.

Examples of the thermoplastic resin include acrylic resins, urethane resins, and ester resins. Among these, it is preferable to use urethane resin, ester resin, or the like.
More specifically, examples of the acrylic resin include an aqueous emulsion obtained from a (meth) acrylic acid alkester monomer, a polymer emulsion obtained by copolymerizing the monomer with styrene, acrylonitrile, and the like. Examples of the urethane resin include an aqueous emulsion obtained by reacting a polyol compound such as polyester polyol, polyether polyol, and polycarbonate polyol with a polyisocyanate. Further, as the ester resin, for example, polyester in a hard segment, There are water-dispersed elastomers of multiblock copolymers using polyether or polyester for the soft segment. Among these, it is preferable to use a water-dispersed urethane resin obtained from polyester polyol or polyether polyol and polyisocyanate. Moreover, these thermoplastic resins may use not only one type but also two or more types.
Further, the coating liquid B for optical substrate is composed of components other than those described above, for example, neutralizers, surfactants or ultraviolet absorbers, and organic materials described in conventionally known documents such as International Publication WO2007 / 026529. A compound, an inorganic compound, etc. may be included.

[Coating film for optical substrate]
As an optical base material for applying the coating liquid for the optical base material, there are various plastic base materials. When this is used as an optical lens, polystyrene resin, allyl resin (especially aromatic allyl resin). ), A plastic lens substrate made of polycarbonate resin, polythiourethane resin, polythioepoxy resin, or the like. Moreover, as a plastic base material used other than an optical lens, there is a plastic base material made of PMMA resin, ABS resin, epoxy resin, polysulfone resin, or the like.
In recent years, optical base materials (plastic lens base materials, etc.) having a relatively high refractive index of 1.7 or more, more specifically 1.71-1.81, have been developed. Has been. Since the coating liquid for optical substrates can be applied to these high refractive optical substrates without any particular problem, it can be used by appropriately selecting from these optical substrates.
However, if the concentration of the high refractive index metal oxide fine particles contained in the coating liquid for an optical substrate is lowered, a relatively low refraction of 1.50 to 1.70, more specifically 1.52 to 1.67. It can be easily applied to an optical substrate having a ratio.

The optical substrate coating solution B, that is, the primer layer film forming coating solution, is directly applied onto the optical substrate by a conventionally known method. On the other hand, the coating liquid A for the optical substrate, that is, the coating liquid for forming the hard coat layer film, is applied directly on the optical substrate by a conventionally known method, or the coating liquid B for the optical substrate is applied. It is applied on the coating film (primer layer film) formed by coating.
Thus, the coating film formed on the optical substrate becomes a desired coating film for an optical substrate, that is, a hard coat layer film or a primer layer film by curing by a conventionally known method.
As a result, the coating material for optical base materials having a high refractive index of 1.70 or more, particularly 1.71 to 1.81, which is highly desired by the recent plastic lens industry and the like, and excellent in weather resistance and light resistance. A film (for example, a hard coat layer film) is obtained. Further, this coating film is obtained as a colorless and transparent material having a haze as low as 0.5% or less. In addition, it has excellent characteristics in scratch resistance, abrasion resistance, impact resistance, sweat resistance, hot water resistance, adhesion, dyeability, and fading resistance required for coating films for optical substrates. Yes.

[Measuring method]
Next, the measurement methods and evaluation test methods used in the examples and others of the present invention will be specifically described as follows.
(1) Average particle diameter A of particles (with average particle diameter of 30 μm or more)
1.0 g of composite oxide particles (titanium-based particles) composed of a spray-dried product having a relatively large particle size (having a particle size of 5 μm or more) were added to Micromesh Sieve (20, 30, 45, 60, 75, 90, 105, 150 μm), and an average particle size is measured using a sieving particle size distribution measuring device (RPS-85EX manufactured by Seishin Enterprise).
Incidentally, this measuring method is suitable for measuring the average particle diameter of a particle group having a particle diameter of 20 to 150 μm.

(2) Average particle diameter B of particles (with an average particle diameter of 0.2 to 30 μm)
A slurry liquid (solid content) in which composite oxide particles (titanium-based particles) composed of spray-dried products having a relatively small particle diameter (with a particle diameter of 0.2 to 5 μm) are dispersed in an aqueous solution containing 40% by weight of glycerin. A concentration of 1.0% by weight) is prepared, and the composite oxide particles are well dispersed by irradiating with ultrasonic waves for 5 minutes using an ultrasonic generator (manufactured by Iuchi, US-2 type). Next, this dispersion is put into a glass cell (length 10 mm, width 10 mm, height 45 cm), and 300 to 10,000 rpm using a centrifugal sedimentation type particle size distribution analyzer (CAPA-700 manufactured by Horiba Seisakusho). The average particle diameter is measured over 2 minutes to 2 hours at the rotation speed. Incidentally, this measuring method is suitable for measuring the average particle diameter of a particle group having a particle diameter of 0.2 to 30 μm.

(3) Average particle diameter C of particles (with an average particle diameter of 200 nm or less)
A solid content of 0.15 prepared by mixing 19.85 g of pure water with 0.15 g of an aqueous dispersion sol (solid content of 20% by weight) of titanium-based fine particles or metal oxide fine particles having a nano-sized particle diameter. % Sample is placed in a quartz cell having a length of 1 cm, a width of 1 cm, and a height of 5 cm, and an ultrafine particle size analyzer (model ELS-Z2 manufactured by Otsuka Electronics Co., Ltd.) using a dynamic light scattering method is used. The particle size distribution of the particle group is measured. In addition, the average particle diameter as used in the field of this invention shows the value computed by cumulant analysis of this measurement result. However, the average particle size of the particles obtained from the particle size distribution of the fine particles measured by the dynamic light scattering method using the ultrafine particle size analyzer is obtained from a TEM photograph of the fine particles taken with a transmission electron microscope. It was found that the average particle diameter of the obtained particles is about 3 times as large. Therefore, the average particle size of the fine particles defined in the present invention is different from the average particle size obtained by other measurement methods. Incidentally, this measuring method is suitable for measuring the average particle diameter of a particle group having a particle diameter of 3 to 1000 nm.

(4) Particle size distribution frequency of particles: Obtained from the frequency distribution of the scattering intensity obtained from the particle size distribution measurement by the dynamic light scattering method used in (3) above. The distribution frequency of particles having a particle diameter of 100 nm or more referred to in the present invention is a value obtained by subtracting from 100 the total value of the distribution frequency (%) of particle groups having a particle diameter of 94.9 nm or less.

(5) Specific surface area of particles About 30 ml of dry powder of composite oxide particles (titanium-based particles) or titanium-based fine particles are collected in a magnetic crucible (type B-2), dried at a temperature of 300 ° C. for 2 hours, and then desiccator. Cool to room temperature. Next, 1 g of a sample is taken, and the specific surface area (m ² / g) is measured by the BET method using a fully automatic surface area measuring device (manufactured by Yuasa Ionics Co., Ltd., Multisorb 12 type). In addition, the specific surface area as used in the field of this invention shows the value calculated from this measurement result.

(6) Crystal form composite oxide particles (titanium particles) or water-dispersed sol of titanium particles is collected in a magnetic crucible (type B-2), dried at 110 ° C. for 12 hours, and placed in a desiccator. Cool to room temperature. Next, after pulverizing for 15 minutes in a mortar, the crystal form is measured using an X-ray diffractometer (RINT1400, manufactured by Rigaku Corporation). In addition, the crystal | crystallization form said by this invention shows the form (for example, rutile type etc.) determined from this measurement result.

(7) X-ray diffraction crystallite diameter of particles Using the X-ray diffractometer used in (6) above, the crystal structure of the fired composite oxide particles (titanium particles) or titanium particles is determined. . In addition, the X-ray diffraction crystallite diameter (D) as used in the field of this invention shows the value computed using the following Scheller formulas.
D = λ / βcos θ
(Where λ is the X-ray wavelength, β is the half-width, and θ is the reflection angle. The wavelength λ of the X-ray (CuK _α- ray) used in this measurement is 0.154056 nm. Also, the reflection angle θ was calculated using 2θ of the measured rutile crystal plane (110).)

(8) Crystalline spacing by X-ray diffraction Using the X-ray diffractometer used in (6) above, it is determined from the result of measuring the crystal structure of the fired composite oxide particles (titanium-based particles) or titanium-based fine particles. The crystal plane spacing (d) in the present invention is a value calculated by measuring the crystal planes (310) and (301) and using the following Bragg equation.
d = λ / 2 sin θ
(Here, λ means the X-ray wavelength, and θ means the reflection angle. Note that the wavelength λ of the X-ray (CuK _α- ray) used in this measurement is 0.154056 nm.)

(9) Relative peak intensity by X-ray diffraction Obtained from the result of measuring calcined composite oxide particles (titanium-based particles) or titanium-based fine particles using the X-ray diffractometer used in (6) above. Note that the relative peak intensity ratio in the present invention, represents the strongest interference line of the rutile-type crystal (110) peak intensity P ² and (310) crystal plane was measured and the peak intensity P ¹ of the crystal plane, the former The relative intensity ratio (P ¹ / P ² ) when the peak intensity P ² is 100 is shown.

(10) Absorbance (log (I _o / I)) of water-dispersed sol containing metal oxide fine particles at a wavelength of 500 nm using a turbidity spectrophotometer (JEOL Ltd. V-550) Is obtained from the measurement result. In this case, water is used as the control solution. The turbidity (τ) referred to in the present invention is a value calculated using the Lambert law formula shown below.
τ (cm ⁻¹ ) = (1 / W) × ln (I ₀ / I)
= (1 / W) x 2.303 x log ( _Io / I)
(W is the cell width (cm), I _o is the intensity (%) of incident light, and I is the intensity (%) of transmitted light.)

(11) Content of metal oxide contained in particles After collecting water-dispersed sol (sample) containing metal oxide fine particles in zirconia balls, drying and firing, Na ₂ O ₂ and NaOH are added and melted. . Further, after being dissolved in H ₂ SO ₄ and HCl and diluted with pure water, using an ICP apparatus (ICPS-8100, manufactured by Shimadzu Corporation), titanium, tin, aluminum, antimony and / or silica are contained. The amount is measured on an oxide equivalent basis (ie TiO ₂ , SnO ₂ , Al ₂ O ₃ , Sb ₂ O ₅ and / or SiO ₂ ).
Next, the sample is collected in a platinum dish, HF and H ₂ SO ₄ are added, heated, and dissolved with HCl. Furthermore, after diluting this with pure water, the content of zirconium is measured by an oxide conversion standard (ZrO ₂ ) using an ICP device (manufactured by Shimadzu Corporation, ICPS-8100).
Then, the sample was taken in a platinum dish and heated by adding HF and H ₂ SO _4, dissolved in HCl. Furthermore, after diluting this with pure water, the content of potassium is measured by an oxide conversion standard (K ₂ O) using an atomic absorption device (manufactured by Hitachi, Ltd., Z-5300).
In addition, content of each metal oxide as used in the field of this invention shows the value calculated from these measurement results.

(12) Refractive index A of particle (calculation method from coating film refractive index)
γ-Glycidoxypropyltrimethoxysilane (Z-6040 manufactured by Toray Dow Corning Co., Ltd., 49.2 wt% in terms of SiO ₂ ) and methanol containing 99.9 wt% methyl alcohol (Jun Hayashi 7.1 g of Yakuhin Co., Ltd.) was mixed, and 3.6 g of 0.01N hydrochloric acid aqueous solution was added dropwise with stirring to the mixture containing the hydrolyzate of the silane compound. 38.6 g of an aqueous dispersion sol containing fine particles (solid concentration 2.0% by weight), 0.3 g of Tris (2.4-pentanedionato) aluminum III (manufactured by Tokyo Chemical Industry Co., Ltd.) and 10 as a leveling agent 0.07 g of a methanol solution containing a weight percent silicone-based surfactant (manufactured by Toray Dow Corning Co., Ltd., L-7006) was added, and the mixture was stirred overnight at room temperature, followed by coating composition A (weight fraction of particles) 10 wt%) is prepared. Here, the “particle weight fraction” means the weight fraction of the titanium-based fine particles or metal oxide fine particles with respect to the total solid content contained in the coating composition, and the same shall apply hereinafter.
Furthermore, the coating composition B (weight of particles) was prepared in the same manner as described above except that the amount of the water-dispersed sol was changed to 77.1 g, 115.6 g, 154.1 g, 192.7 g, and 212.0 g. Fraction: 20% by weight), coating composition C (weight fraction of particles: 30% by weight), coating composition D (weight fraction of particles: 40% by weight), coating composition E (weight fraction of particles) : 50 wt%) and coating composition F (particle weight fraction: 55 wt%).
In addition, for the water dispersion sol containing the metal oxide fine particles (solid content concentration 20.0% by weight), the amount of the water dispersion sol mixed is 3.9 g, 7.7 g, 11.6 g, 15.4 g, 19 Coating composition A (particle weight fraction: 10% by weight), coating composition B (particle weight fraction: 20% by weight) in the same manner as above except that the amount was changed to 2g and 21.2g. , Coating composition C (particle weight fraction: 30 wt%), coating composition D (particle weight fraction: 40 wt%), coating composition E (particle weight fraction: 50 wt%) and coating Compositions F (particle weight fraction: 55% by weight) are respectively prepared.

Next, the coating compositions A to F were respectively applied at a rotational speed of 300 rpm onto a silicon wafer substrate maintained at a temperature of 40 ° C. using a spin coater (manufactured by Mikasa Co., Ltd., MS-A200). A coating film is formed by drying at a temperature of 120 ° C. for 2 hours. Next, about the coating film formed on each silicon wafer base material, coating-film refractive index Nav '(actual value) is measured using a spectroscopic ellipsometer (the Sopra company make, SOPRA ESVG).
Next, using the following volume fraction / weight fraction conversion formula (see formula 1) and Maxwell-Garnett formula (see formula 2), the above particles are used. The theoretical coating film refractive index Nav (calculated value) is calculated with respect to the weight fraction.
Next, the deviation between the coating film refractive index Nav calculated based on these equations and the coating film refractive index Nav ′ measured above was obtained, and the deviation square was calculated from this, and the deviation square was calculated from the sum of the calculated deviation squares. Find the sum. The deviation sum of squares is obtained for each assumed particle refractive index Np (for example, a plurality of assumed particle refractive indices assumed in at least 0.01 increments from the range of 1.70 to 2.70), and the minimum value is obtained. The refractive index shown is the refractive index Np ′ of the particles. That is, this is a method for measuring particle refractive index by the least square method. (In this case, it is preferable to plot the value on a graph with the assumed particle refractive index as the horizontal axis and the deviation sum of squares as the vertical axis.)

In the above equation 1, f (m) is the volume fraction of particles relative to the total solid content, m is the weight fraction of particles relative to the total solid content, dm is the specific gravity of the matrix component (here, γ-glycidoxypropyl trimethyl). The specific gravity of methoxysilane is 1.07.), Dp means the specific gravity of titanium-based fine particles or metal oxide fine particles. Here, the above-mentioned dp is a specific gravity calculated from the content of the metal component of the titanium-based fine particles or metal oxide fine particles, and TiO ₂ , SiO ₂ , SnO ₂ , Al ₂ O ₃ contained in these particles. Specific gravity of 4.26, 2.20, 7.00, and 3.97, respectively.

In the above formula 2, Nav is the refractive index of the coating film, and Nm is the refractive index of the matrix component (here, 1.499 which is the refractive index of the hydrolyzate of γ-glycidoxypropyltrimethoxysilane). Np means the refractive index of titanium-based fine particles or metal oxide fine particles.
In this measurement method, the refractive index of a particle group having a refractive index of 1.70 to 2.70 can be measured. In particular, a refractive index exceeding 2.31, which cannot be measured by the standard liquid method shown below. It is suitable for measuring the refractive index of a particle group having. In addition, the refractive index of the particle | grains calculated | required with this measuring method has substantially the same result as the refractive index (however, the range of 1.70-2.31) of the particle | grains measured by the standard liquid method.

(13) Refractive index B of particles (standard solution method)
An aqueous dispersion sol or organic solvent dispersion sol containing titanium-based fine particles or metal oxide fine particles is applied to an evaporator to evaporate the dispersion medium, and then dried at a temperature of 120 ° C. to obtain a dry powder. Next, 2 to 3 drops of a standard solution reagent having a known refractive index is dropped on a glass substrate, and a dry powder of the titanium-based fine particles or the metal oxide fine particles is mixed therewith to prepare a mixed solution. This operation is performed using standard liquid reagents having various refractive indexes (Cargill standard refractive index liquid manufactured by MORITEX), and the refractive index of the standard liquid reagent when the mixed solution becomes transparent is the refractive index of the particles. And
Incidentally, this measuring method can measure the refractive index of a particle group having a refractive index of 1.70 to 2.31. However, currently available standard solution reagents can be applied only to particles having a refractive index of 2.31 or less, and thus the refractive index of particles having a refractive index exceeding 2.31 cannot be measured by this method. Therefore, in the present invention, the above measurement method A was adopted, but the refractive index of the particles (however, the refractive index is in the range of 1.70 to 2.31) was measured using the measurement method B for reference. .

(14) Photocatalytic activity test of particles A solid content of 6.6 wt% prepared by mixing 9.34 g of pure water with 0.66 g of an aqueous dispersion sol (solid content of 20 wt%) containing metal oxide fine particles. 9.70 g of a yellow glycerol solution of sunset yellow dye having a solid content of 0.02% by weight is mixed with 0.33 g of a% sample. This is then sealed in a quartz cell having a length of 1 mm, a width of 1 cm and a height of 5 cm. Next, using an ultraviolet lamp (SLUV-6 manufactured by AS ONE) in which the wavelength range of I-line (wavelength 365 nm) is selected, the quartz cell is irradiated with an irradiation distance of 5.5 m to an irradiation intensity of 0.4 mW / cm ² (wavelength). Irradiation with ultraviolet rays is performed for 180 minutes at a conversion of 365 nm.
On the other hand, before and after UV irradiation, the absorbance (A ₀ and A ₁₈₀ ) of the sample at a wavelength of 490 nm is measured, and the dye fading change rate is calculated from the following equation. Furthermore, the photocatalytic activity of the particles is evaluated based on the following criteria.
Fading change rate (%) = (1−A ₁₈₀ / A ₀ ) × 100
Evaluation criteria ○: Fading change rate is less than 20% Δ: Fading change rate is 20% to less than 50% ×: Fading change rate is 50% or more

(15) Light resistance test of particles A solid content prepared by mixing 4.50 g of pure water and 12.6 g of methanol with 0.90 g of an aqueous dispersion sol (solid content 20% by weight) containing metal oxide fine particles. 18.00 g of a sample having a content of 1.0% by weight is sealed in a quartz cell having a length of 1 mm, a width of 1 cm, and a height of 5 cm. Next, using an ultraviolet lamp (SLUV-6 manufactured by AS ONE) in which the wavelength region of I-line (wavelength 365 nm) is selected, the quartz cell is irradiated with an irradiation intensity of 0.4 mW / cm ² (wavelength 365 nm) from an irradiation distance of 5.5 cm. Irradiation with ultraviolet rays is performed for 60 minutes. The color change of the liquid mixture exposed to the ultraviolet rays is visually observed and evaluated according to the following criteria.
Evaluation criteria ○: Blue discoloration starts in 1 hour or more Δ: Blue discoloration starts in 0.5 hours to less than 1 hour ×: Blue discoloration starts in less than 0.5 hours

(16) Appearance of coating film (interference fringes)
A fluorescent lamp “trade name: Mellow 5N” (manufactured by Toshiba Lighting & Technology Co., Ltd., three-wavelength daylight white fluorescent lamp) is mounted in a box whose inner wall is black, and the hard coat layer film ( Reflection is performed on the surface of the antireflection film formed on the metal oxide fine particles (including the metal oxide fine particles), and the occurrence of rainbow patterns (interference fringes) due to light interference is visually confirmed, and evaluated according to the following criteria.
S: There is almost no interference fringe. A: The interference fringe is not conspicuous. B: Although the interference fringe is recognized, it is within an allowable range. C: The interference fringe is conspicuous. D: There is an interference fringe with glare.

(17) Appearance of the coating film (cloudy)
A fluorescent lamp “trade name: Mellow 5N” (manufactured by Toshiba Lighting & Technology Co., Ltd., three-wavelength daylight white fluorescent lamp) is mounted in a box whose inner wall is black and has a hard coat layer film containing the metal oxide fine particles. The sample substrate is placed vertically directly under the fluorescent lamp, and the transparency (degree of cloudiness) is visually confirmed and evaluated according to the following criteria.
A: No haze B: Slight haze C: Clear haze D: Significant haze

(18) Scratch resistance test of coating film The surface of the sample substrate on which the hard coat layer film is formed is manually rubbed with Bonstar Steel Wool # 0000 (manufactured by Nippon Steel Wool Co., Ltd.), and the degree of damage is visually determined. The evaluation is based on the following criteria.
A: Almost no flaws B: Some flaws enter C: Some flaws enter

(19) Adhesion test of coating film On the lens surface of the sample substrate on which the hard coat layer film is formed, cuts are made at intervals of 1 mm with a knife to form 100 squares of 1 mm square, and the cellophane adhesive tape is strongly After pressing, the plastic lens substrate is rapidly pulled in the direction of 90 degrees with respect to the in-plane direction of the plastic lens substrate, this operation is performed a total of five times, the number of squares that do not peel off is counted, and the following criteria are evaluated.
Good: The number of cells not peeled is 95 or more. Bad: The number of cells not peeled is less than 95.

(20) Weather resistance test of coating film After subjecting the sample substrate on which the hard coat layer film was formed to an exposure test using a xenon weather meter (X-75 type, manufactured by Suga Test Instruments Co., Ltd.), the appearance was confirmed and the adhesion was Perform the same test as the test and evaluate according to the following criteria. The exposure time is 200 hours for a substrate having an antireflection film and 50 hours for a substrate not having an antireflection film.
Good: The number of cells not peeled is 95 or more. Bad: The number of cells not peeled is less than 95.

(21) Light resistance test of coating film Irradiation with ultraviolet rays is performed for 50 hours by a mercury lamp for fading test (H400-E manufactured by Toshiba Corporation), and the lens color before and after the test is visually confirmed, and evaluated according to the following criteria. The irradiation distance between the lamp and the test piece is 70 mm, and the output of the lamp is adjusted so that the surface temperature of the test piece is 45 ± 5 ° C. This test was conducted on a plastic lens having an antireflection film applied to the surface of the hard coat layer.
○: Not much discoloration is observed Δ: Some discoloration is observed ×: Clear discoloration is recognized

[Example]
Hereinafter, the present invention will be specifically described based on examples. However, the present invention is not limited to the scope described in these examples.

[ Reference Example 1]
Preparation of water-dispersed sol containing titanium-based fine particles 11.37 kg of titanium tetrachloride aqueous solution containing 7.75 wt% of titanium tetrachloride (manufactured by Osaka Titanium Technologies Co., Ltd.) in terms of TiO ₂ , and 15 wt% of ammonia Ammonia water containing (manufactured by Ube Industries) 4.41 kg was mixed to prepare a white slurry liquid having a pH of 9.5. The slurry was then filtered and washed with pure water to obtain 9.27 kg of a hydrous titanate cake having a solid content of 10% by weight.
Next, 10.60 kg of hydrogen peroxide containing 35% by weight of hydrogen peroxide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 20.00 kg of pure water are added to the cake, and then at a temperature of 80 ° C. for 1 hour. The mixture was heated under stirring, and 52.87 kg of pure water was further added to obtain 92.75 kg of an aqueous solution of titanic acid peroxide containing 1 wt% of titanic acid peroxide on a TiO ₂ basis. This aqueous solution of titanic acid peroxide was transparent yellowish brown and had a pH of 8.5.

Next, 4.4 kg of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with 92.75 kg of the aqueous solution of titanic acid titanate, and potassium stannate (manufactured by Showa Kako Co., Ltd.) was converted into SnO _2. 11.59 kg of an aqueous potassium stannate solution containing 1% by weight on a standard basis was gradually added with stirring.
Next, after separating the cation exchange resin incorporating potassium ions and the like, 0.44 kg of silica sol (manufactured by JGC Catalysts & Chemicals Co., Ltd.) containing 15% by weight of silica fine particles having an average particle diameter of 7 nm and 6.22 kg of pure water. Were mixed and heated in an autoclave (pressure-resistant glass industry, 120 L) at a temperature of 165 ° C. for 18 hours.

Next, after cooling the obtained mixed aqueous solution to room temperature, it was concentrated with an ultrafiltration membrane device (ACV-3010, manufactured by Asahi Kasei Co., Ltd.), and 9.90 kg of the mixed aqueous solution having a solid content of 10% by weight. Got.
The solid contained in the mixed aqueous solution thus obtained was measured by the above method, and as a result, it was a composite oxide fine particle (primary particle) containing titanium, tin and silicon having a rutile crystal structure. . Furthermore, when the content of the metal component contained in the composite oxide fine particles was measured, 82.8% by weight of TiO ₂ , 10.1% by weight of SnO ₂ , SiO ₂ 5 based on the oxide conversion standard of each metal component. And 4% by weight and 1.7% by weight of K ₂ O. The pH of the mixed aqueous solution was 9.2.
Next, 9.00 kg of the mixed aqueous solution containing the composite oxide fine particles was spray-dried (inlet temperature: 260 ° C., outlet temperature: 55 ° C.) using a spray dryer (NIRO ATOMIZER manufactured by NIRO). As a result, 0.63 kg of a dry powder composed of composite oxide particles having an average particle diameter of about 2 μm was obtained.

Next, 0.63 kg of the dry powder of the composite oxide particles obtained above was fired for 1 hour at a temperature of 600 ° C. in an air atmosphere to obtain 0.59 kg of a fired powder of the composite oxide particles. It was.
The composite oxide particles (titanium-based particles) obtained by firing in this way have a rutile crystal structure, a specific surface area of 138 m ² / g, and an X-ray diffraction crystallite diameter of 8. It was 9 nm. Further, the interplanar spacing of (310) crystal planes determined from X-ray diffraction was 0.1452 nm, and the interplanar spacing of (301) crystal planes was 0.1357 nm. Furthermore, as determined by X-ray diffraction, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ²⁾ was 13/100 .

Next, 0.17 kg of the calcined powder of the obtained composite oxide particles (titanium particles) was dispersed in 250.4 g of pure water, and 24.8 g of 10 wt% potassium hydroxide aqueous solution was added thereto. The pH was adjusted to 11.0. Next, 1.27 kg of quartz beads having a particle size of 0.1 to 0.2 mm (high-purity silica beads 015 manufactured by MRC Unitech Co., Ltd.) was added to this mixed aqueous solution, The composite oxide particles were pulverized for 180 minutes. Then, after separating and removing the quartz beads using a stainless steel filter having an opening of 44 μm, 840.0 g of pure water was further added and stirred, and 1.19 kg of an aqueous dispersion sol having a solid content of 11 wt% was added. Obtained.
The aqueous dispersion sol containing composite oxide fine particles obtained by pulverization in this way was milky white. The average particle size of the composite oxide fine particles contained in the water-dispersed sol was 104 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 58.6%.

Next, 0.12 kg of pure water was added to 1.19 kg of the water-dispersed sol to obtain a water-dispersed sol having a solid concentration of 10% by weight, and 0.29 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation). Mix and stir for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 40.1 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and this water-dispersed sol was subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.) to 12,000 rpm. Then, the coarse particles having a particle diameter of 100 nm or more were classified and removed. As a result, 1.12 kg of an aqueous dispersion sol having a solid content of 6.6% by weight was obtained.

Next, 1.82 kg of the above water-dispersed sol (solid content 6.6% by weight) is mixed with 2.58 kg of pure water, and 3.70 kg of water-dispersed sol having a solid content of 2.0% by weight. Got. Next, this water-dispersed sol was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 5 L) and heat-treated at a temperature of 165 ° C. for 18 hours.
Next, 0.15 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with the water dispersion sol taken out from the autoclave and cooled to room temperature, and stirred for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 9.8 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Further, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain a water-dispersed sol having a deionized solid content of 2.0% by weight. Thus, 3.62 kg of an aqueous dispersion sol containing titanium-based fine particles (hereinafter referred to as “CP-1”) obtained by firing and pulverizing the composite oxide particles and further classifying and removing coarse particles was obtained.

The water-dispersed sol containing titanium-based fine particles thus obtained was transparent milky white and had a turbidity of 0.42 cm ⁻¹ . The average particle size of the titanium-based fine particles contained in the water-dispersed sol was 31 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 0%.
The titanium-based fine particles have a rutile-type crystal structure, and the specific surface area, X-ray diffraction crystallite diameter, crystal plane spacing and relative peak intensity ratio obtained from X-ray diffraction are determined by the composite oxidation. It showed the same value as the product particles (titanium-based particles before pulverization).
Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, TiO ₂ 84.4 wt%, SnO ₂ 9.9 wt%, SiO ₂ 5. 3 wt% and K ₂ O 0.4 wt%. The specific gravity of the titanium-based fine particles obtained from this metal content was 4.20.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.544, 1.584, 1.630, 1.682, 1.743, 1.775. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula and the coating refractive index Nav calculated from the Maxwell-Garnet formula is 0.000167. The refractive index of the particles showing the minimum value was 2.35. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.35.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[ Reference Example 2]
Preparation of water-dispersed sol containing titanium-based fine particles 12.09 kg of titanium tetrachloride aqueous solution containing 7.75% by weight of titanium tetrachloride (manufactured by Osaka Titanium Technologies Co., Ltd.) in terms of TiO ₂ , and 15% by weight of ammonia 4.69 kg of ammonia water (manufactured by Ube Industries) was mixed to prepare a white slurry liquid having a pH of 9.5. The slurry was then filtered and washed with pure water to obtain 9.87 kg of a hydrous titanate cake having a solid content of 10% by weight.
Next, 11.28 kg of hydrogen peroxide containing 35% by weight of hydrogen peroxide (Mitsubishi Gas Chemical Co., Ltd.) and 20.00 kg of pure water were added to this cake, and then at a temperature of 80 ° C. for 1 hour. The mixture was heated under stirring, and 57.52 kg of pure water was further added to obtain 98.67 kg of an aqueous solution of titanic acid peroxide containing 1 wt% of titanic acid peroxide on a TiO ₂ basis. This aqueous solution of titanic acid peroxide was transparent yellowish brown and had a pH of 8.5.

Next, 4.7 kg of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with 98.67 kg of the above-mentioned aqueous solution of titanic acid titanate, and potassium stannate (manufactured by Showa Kako Co., Ltd.) was converted into SnO _2. 12.33 kg of an aqueous potassium stannate solution containing 1% by weight on a standard basis was gradually added with stirring.
Next, after separating the cation exchange resin which took in potassium ion etc., it put into the autoclave (The pressure | voltage resistant glass industry Co., Ltd. product, 120L), and heated at the temperature of 165 degreeC for 18 hours.

Next, after cooling the obtained mixed aqueous solution to room temperature, it was concentrated with an ultrafiltration membrane device (ACV-3010, manufactured by Asahi Kasei Co., Ltd.), and 9.90 kg of the mixed aqueous solution having a solid content of 10% by weight. Got.
The solids contained in the mixed aqueous solution thus obtained were measured by the above method. As a result, they were complex oxide fine particles (primary particles) containing titanium and tin having a rutile crystal structure. Furthermore, when the content of the metal component contained in the composite oxide fine particles was measured, 87.2% by weight of TiO ₂ , 11.0% by weight of SnO ₂ , and K _{2 on} the oxide conversion standard of each metal component. It was 1.8% by weight of O. The pH of the mixed aqueous solution was 10.0.
Next, 9.00 kg of the mixed aqueous solution containing the composite oxide fine particles was spray-dried (inlet temperature: 260 ° C., outlet temperature: 55 ° C.) using a spray dryer (NIRO ATOMIZER manufactured by NIRO). As a result, 0.63 kg of a dry powder composed of composite oxide particles having an average particle diameter of about 2 μm was obtained.

Next, 0.63 kg of the dried powder of composite oxide particles obtained above was calcined at 500 ° C. for 1 hour in an air atmosphere to obtain 0.59 kg of calcined powder of composite oxide particles. It was.
The composite oxide particles (titanium-based particles) obtained by firing in this way have a rutile crystal structure, a specific surface area of 124 m ² / g, and an X-ray diffraction crystallite diameter of 9. It was 6 nm. Further, the interplanar spacing of (310) crystal planes determined from X-ray diffraction was 0.1447 nm, and the interplanar spacing of (301) crystal planes was 0.1366 nm. Furthermore, as determined by X-ray diffraction, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ²⁾ was 14/100 . An X-ray diffraction chart (XRD chart) obtained at this time is as shown in FIG.

Next, 0.17 kg of the calcined powder of the obtained composite oxide particles (titanium particles) was dispersed in 250.4 g of pure water, and 24.8 g of 10 wt% potassium hydroxide aqueous solution was added thereto. The pH was adjusted to 11.0. Next, 1.27 kg of quartz beads having a particle size of 0.1 to 0.2 mm (high-purity silica beads 015 manufactured by MRC Unitech Co., Ltd.) was added to this mixed aqueous solution, The composite oxide particles were pulverized for 180 minutes. Then, after separating and removing the quartz beads using a stainless steel filter having an opening of 44 μm, 840.0 g of pure water was further added and stirred, and 1.17 kg of an aqueous dispersion sol having a solid content of 11 wt% was added. Obtained.
The aqueous dispersion sol containing composite oxide fine particles obtained by pulverization in this way was milky white. The average particle size of the composite oxide fine particles contained in the water-dispersed sol was 106 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 59.1%.

Next, 0.12 kg of pure water was added to 1.17 kg of the water dispersion sol to obtain a water dispersion sol having a solid content concentration of 10% by weight, and 0.29 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation). Mix and stir for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 39.4 g of a cation exchange resin (Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and this water-dispersed sol was subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.) to 12,000 rpm. Then, the coarse particles having a particle diameter of 100 nm or more were classified and removed. As a result, 1.13 kg of an aqueous dispersion sol having a solid content of 6.4% by weight was obtained.

Subsequently, 1.49 kg of the water-dispersed sol (solid content is 6.4% by weight) is mixed with 2.49 kg of pure water to obtain 3.62 kg of water-dispersed sol having a solid content of 2.0% by weight. Got. Next, this water-dispersed sol was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 5 L) and heat-treated at a temperature of 165 ° C. for 18 hours.
Next, 0.14 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with the water dispersion sol taken out from the autoclave and cooled to room temperature, and stirred for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 9.5 g of a cation exchange resin (Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Further, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain a water-dispersed sol having a deionized solid content of 2.0% by weight. As a result, 3.52 kg of an aqueous dispersion sol containing titanium-based fine particles (hereinafter referred to as “CP-2”) obtained by firing and pulverizing the composite oxide particles and further classifying and removing coarse particles was obtained.

The water-dispersed sol containing titanium-based fine particles thus obtained was transparent milky white and had a turbidity of 0.51 cm ⁻¹ . The average particle diameter of the titanium-based fine particles contained in the water-dispersed sol was 35 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
The titanium-based fine particles have a rutile-type crystal structure, and the specific surface area, X-ray diffraction crystallite diameter, crystal plane spacing and relative peak intensity ratio obtained from X-ray diffraction are determined by the composite oxidation. It showed the same value as the product particles (titanium-based particles before pulverization).
Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, TiO ₂ 88.5 wt%, SnO ₂ 11.1 wt% and K ₂ O 0. It was 4% by weight. The specific gravity of the titanium-based fine particles determined from the metal content was 4.44.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.532, 1.598, 1.622, 1.681, 1.746, 1.783. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula and the coating refractive index Nav calculated from the Maxwell-Garnet formula is 0.000421. The refractive index of the particles showing the minimum value was 2.38. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.38.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[ Reference Example 3]
Preparation of water-dispersed sol containing titanium-based fine particles
In the same manner as in Reference Example 1, 0.63 kg of dry powder composed of composite oxide particles having an average particle diameter of about 2 μm was obtained.
Next, 0.63 kg of the dry powder of the composite oxide particles was fired in an air atmosphere at a temperature of 500 ° C. for 1 hour to obtain 0.59 kg of a fired powder of the composite oxide particles.
The composite oxide particles (titanium particles) obtained by firing in this way have a rutile-type crystal structure, a specific surface area of 150 m ² / g, and an X-ray diffraction crystallite diameter of 8. It was 2 nm. Further, the interplanar spacing of (310) crystal planes determined from X-ray diffraction was 0.1448 nm, and the interplanar spacing of (301) crystal planes was 0.1357 nm. Furthermore, as determined by X-ray diffraction, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ²⁾ was 14/100 . An X-ray diffraction chart (XRD chart) obtained at this time is as shown in FIG.

Next, 0.17 kg of the calcined powder of the obtained composite oxide particles (titanium particles) was dispersed in 250.4 g of pure water, and 24.8 g of 10 wt% potassium hydroxide aqueous solution was added thereto. The pH was adjusted to 11.0. Next, 1.27 kg of quartz beads having a particle size of 0.1 to 0.2 mm (high-purity silica beads 015 manufactured by MRC Unitech Co., Ltd.) was added to this mixed aqueous solution, The composite oxide particles were pulverized for 180 minutes. Then, after separating and removing the quartz beads using a stainless steel filter having an opening of 44 μm, 840.0 g of pure water was further added and stirred, and 1.35 kg of an aqueous dispersion sol having a solid content of 11 wt% was added. Obtained.
The aqueous dispersion sol containing composite oxide fine particles obtained by pulverization in this way was milky white. The average particle size of the composite oxide fine particles contained in the water-dispersed sol was 98 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 53.4%.

Next, 0.14 kg of pure water was added to 1.35 kg of the water-dispersed sol to obtain a water-dispersed sol having a solid concentration of 10% by weight, and 0.33 kg of an anion exchange resin (Mitsubishi Chemical Corporation) was added. Mix and stir for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 45.4 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and this water-dispersed sol was subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.) to 12,000 rpm. Then, the coarse particles having a particle diameter of 100 nm or more were classified and removed. As a result, 1.30 kg of an aqueous dispersion sol having a solid content of 6.6% by weight was obtained.

Next, 1.30 kg of the water-dispersed sol (solid content 6.6% by weight) is mixed with 3.51 kg of pure water, and 4.81 kg of water-dispersed sol having a solid content of 2.0% by weight. Got. Next, this water-dispersed sol was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 5 L) and heat-treated at a temperature of 165 ° C. for 18 hours.
Next, 0.19 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with the water dispersion sol taken out from the autoclave and cooled to room temperature, and stirred for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 12.7 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Further, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain a water-dispersed sol having a deionized solid content of 2.0% by weight. As a result, 4.76 kg of an aqueous dispersion sol containing titanium-based fine particles (hereinafter referred to as “CP-3”) obtained by firing and pulverizing the composite oxide particles and further classifying and removing coarse particles was obtained.

The water-dispersed sol containing titanium-based fine particles thus obtained was transparent milky white, and its turbidity was 0.28 cm ⁻¹ . The average particle diameter of the titanium-based fine particles contained in the water-dispersed sol was 29 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
The titanium-based fine particles have a rutile-type crystal structure, and the specific surface area, X-ray diffraction crystallite diameter, crystal plane spacing and relative peak intensity ratio obtained from X-ray diffraction are determined by the composite oxidation. It showed the same value as the product particles (titanium-based particles before pulverization).
Furthermore, measurement of the content of the metal component contained in the titanium-based fine particles, in terms of oxide based on the respective metal components, TiO ₂ 83.8 wt%, SnO ₂ 10.5 wt%, SiO ₂ 5. 4 was wt% and K ₂ O0.3% by weight. The specific gravity of the titanium-based fine particles determined from the metal content was 4.21.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.534, 1.573, 1.619, 1.671, 1.731, 1.764. Furthermore, the minimum value of the sum of square deviations obtained from the coating film refractive index Nav ′ and the coating volume refractive index Nav calculated from the volume fraction / weight fraction conversion formula and the Maxwell-Garnet formula is 0.000005. The refractive index of the particles showing the minimum value was 2.29. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.29. Incidentally, the refractive index of the titanium-based fine particles measured by the refractive index measurement method B (standard solution method) was 2.29.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[ Reference Example 4]
Preparation of water-dispersed sol containing titanium-based fine particles
In the same manner as in Reference Example 1, 0.63 kg of dry powder composed of composite oxide particles having an average particle diameter of about 2 μm was obtained.
Next, 0.63 kg of the dry powder of the composite oxide particles was fired for 1 hour at a temperature of 700 ° C. in an air atmosphere to obtain 0.59 kg of a fired powder of the composite oxide particles.
The composite oxide particles (titanium particles) obtained by firing in this way have a rutile crystal structure, a specific surface area of 113 m ² / g, and an X-ray diffraction crystallite diameter of 10. It was 0 nm. Further, the interplanar spacing of (310) crystal planes determined from X-ray diffraction was 0.1453 nm, and the interplanar spacing of (301) crystal planes was 0.1363 nm. Furthermore, as determined by X-ray diffraction, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P1 / P ²⁾ was 12/100.

Next, 0.17 kg of the calcined powder of the obtained composite oxide particles (titanium particles) was dispersed in 250.4 g of pure water, and 24.8 g of 10 wt% potassium hydroxide aqueous solution was added thereto. The pH was adjusted to 11.0. Next, 1.27 kg of quartz beads having a particle size of 0.1 to 0.2 mm (high-purity silica beads 015 manufactured by MRC Unitech Co., Ltd.) was added to this mixed aqueous solution, The composite oxide particles were pulverized for 180 minutes. Then, after separating and removing the quartz beads using a stainless steel filter having an opening of 44 μm, 840.0 g of pure water was further added and stirred, and 1.18 kg of an aqueous dispersion sol having a solid content of 11 wt% was added. Obtained.
The aqueous dispersion sol containing composite oxide fine particles obtained by pulverization in this way was milky white. The average particle size of the composite oxide fine particles contained in the water-dispersed sol was 109 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 59.6%.

Next, 0.12 kg of pure water was added to 1.18 kg of the water-dispersed sol to obtain a water-dispersed sol having a solid concentration of 10% by weight, and 0.29 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation). Mix and stir for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 39.7 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and this water-dispersed sol was subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.) to 12,000 rpm. Then, the coarse particles having a particle diameter of 100 nm or more were classified and removed. As a result, 1.12 kg of an aqueous dispersion sol having a solid content of 6.6% by weight was obtained.

Subsequently, 2.52 kg of pure water was mixed with 1.12 kg of the water-dispersed sol (solid content: 6.6 wt%) to obtain 3.64 kg of water-dispersed sol having a solid content of 2.0 wt%. Got. Next, this water-dispersed sol was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 5 L) and heat-treated at a temperature of 165 ° C. for 18 hours.
Next, 0.14 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with the water dispersion sol taken out from the autoclave and cooled to room temperature, and stirred for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 9.6 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Further, separation and removal were performed using a stainless steel filter having an opening of 44 μm to obtain a water-dispersed sol having a deionized solid content of 2.0% by weight. Thus, 3.54 kg of an aqueous dispersion sol containing titanium-based fine particles (hereinafter referred to as “CP-4”) obtained by firing and pulverizing the composite oxide particles and further classifying and removing coarse particles was obtained.

The water-dispersed sol containing titanium-based fine particles thus obtained was transparent milky white and had a turbidity of 0.48 cm ⁻¹ . The average particle size of the titanium-based fine particles contained in the water-dispersed sol was 38 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 0%.
The titanium-based fine particles have a rutile-type crystal structure, and the specific surface area, X-ray diffraction crystallite diameter, crystal plane spacing and relative peak intensity ratio obtained from X-ray diffraction are determined by the composite oxidation. It showed the same value as the product particles (titanium-based particles before pulverization).
Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, TiO ₂ 86.9% by weight, SnO ₂ 10.9% by weight, SiO ₂ 1. 8 was wt% and K ₂ O0.4% by weight. The specific gravity of the titanium-based fine particles determined from the metal content was 4.36.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.536, 1.581, 1.631, 1.589, 1.755, It was 1.802. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating film refractive index Nav calculated from the Maxwell-Garnet formula is 0.000674. The refractive index of the particles showing the minimum value was 2.43. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.43.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[ Reference Example 5]
Preparation of water-dispersed sol containing titanium-based fine particles
In the same manner as in Reference Example 2, 0.63 kg of dry powder composed of composite oxide particles having an average particle size of about 2 μm was obtained.
Next, 0.63 kg of the dry powder of the composite oxide particles was fired for 1 hour at a temperature of 700 ° C. in an air atmosphere to obtain 0.59 kg of a fired powder of the composite oxide particles.
The composite oxide particles (titanium-based particles) obtained by firing in this way have a rutile crystal structure, a specific surface area of 82 m ² / g, and an X-ray diffraction crystallite diameter of 13. It was 4 nm. Further, the interplanar spacing of (310) crystal planes determined from X-ray diffraction was 0.1453 nm, and the interplanar spacing of (301) crystal planes was 0.1370 nm. Furthermore, as determined by X-ray diffraction, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ²⁾ was 11/100 . An X-ray diffraction chart (XRD chart) obtained at this time is as shown in FIG.

Next, 0.17 kg of the calcined powder of the obtained composite oxide particles (titanium particles) was dispersed in 250.4 g of pure water, and 24.8 g of 10 wt% potassium hydroxide aqueous solution was added thereto. The pH was adjusted to 11.0. Next, 1.27 kg of quartz beads having a particle size of 0.1 to 0.2 mm (high-purity silica beads 015 manufactured by MRC Unitech Co., Ltd.) was added to this mixed aqueous solution, The composite oxide particles were pulverized for 180 minutes. Then, after separating and removing the quartz beads using a stainless steel filter having an opening of 44 μm, 840.0 g of pure water was further added and stirred, and 1.18 kg of an aqueous dispersion sol having a solid content of 11 wt% was added. Obtained.
The aqueous dispersion sol containing composite oxide fine particles obtained by pulverization in this way was milky white. The average particle size of the composite oxide fine particles contained in the water-dispersed sol was 115 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 62.0%.

Next, 0.12 kg of pure water was added to 1.18 kg of the water-dispersed sol to obtain a water-dispersed sol having a solid concentration of 10% by weight, and 0.29 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation). Mix and stir for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 39.7 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and this water-dispersed sol was subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.) to 12,000 rpm. Then, the coarse particles having a particle diameter of 100 nm or more were classified and removed. As a result, 1.13 kg of an aqueous dispersion sol having a solid content of 5.9% by weight was obtained.

Next, 2.13 kg of pure water was mixed with 1.13 kg of the water dispersion sol (solid content 5.9 wt%) to obtain 3.33 kg of water dispersion sol having a solid content of 2.0 wt%. Got. Next, this water-dispersed sol was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 5 L) and heat-treated at a temperature of 165 ° C. for 18 hours.
Next, 0.13 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with the water-dispersed sol taken out from the autoclave and cooled to room temperature, and stirred for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 8.8 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Further, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain a water-dispersed sol having a deionized solid content of 2.0% by weight. As a result, 3.28 kg of an aqueous dispersion sol containing titanium-based fine particles (hereinafter referred to as “CP-5”) obtained by firing and pulverizing the composite oxide particles and further classifying and removing coarse particles was obtained.

The water-dispersed sol containing titanium-based fine particles thus obtained was transparent milky white, and its turbidity was 0.64 cm ⁻¹ . The average particle size of the titanium-based fine particles contained in the water-dispersed sol was 41 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 0%.
The titanium-based fine particles have a rutile-type crystal structure, and the specific surface area, X-ray diffraction crystallite diameter, crystal plane spacing and relative peak intensity ratio obtained from X-ray diffraction are determined by the composite oxidation. It showed the same value as the product particles (titanium-based particles before pulverization).
Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, TiO ₂ 88.5 wt%, SnO ₂ 11.1 wt% and K ₂ O 0. It was 4% by weight. The specific gravity of the titanium-based fine particles determined from the metal content was 4.44.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.542, 1.592, 1.644, 1.716, 1.793, It was 1.839. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula and the coating refractive index Nav calculated from the Maxwell-Garnet formula is 0.000358. The refractive index of the particles showing the minimum value was 2.62. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.62.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[Comparative Example 1]
Preparation of water-dispersed sol containing titanium-based fine particles
In the same manner as in Reference Example 1, 0.63 kg of dry powder composed of composite oxide particles having an average particle diameter of about 2 μm was obtained.
The dried powder of the composite oxide particles was used as it was without firing.
The composite oxide particles (titanium particles) had a rutile crystal structure, a specific surface area of 215 m ² / g, and an X-ray diffraction crystallite diameter of 7.1 nm. Further, the interplanar spacing of (310) crystal planes determined from X-ray diffraction was 0.1365 nm, and the interplanar spacing of (301) crystal planes was 0.1354 nm. Furthermore, as determined by X-ray diffraction, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ²⁾ was 24/100 . An X-ray diffraction chart (XRD chart) obtained at this time is as shown in FIG.

Next, 0.17 kg of the obtained dry powder of composite oxide particles (titanium-based particles) was dispersed in 250.4 g of pure water, and 24.8 g of 10 wt% aqueous potassium hydroxide solution was added thereto. The pH was adjusted to 11.0. Next, 1.27 kg of quartz beads having a particle size of 0.1 to 0.2 mm (high-purity silica beads 015 manufactured by MRC Unitech Co., Ltd.) was added to this mixed aqueous solution, The composite oxide particles were pulverized for 180 minutes. Then, after separating and removing the quartz beads using a stainless steel filter having an opening of 44 μm, 840.0 g of pure water was further added and stirred to obtain 1.45 kg of an aqueous dispersion sol having a solid content of 11% by weight. Obtained.
The aqueous dispersion sol containing composite oxide fine particles obtained by pulverization in this way was milky white. The average particle size of the composite oxide fine particles contained in the water-dispersed sol was 136 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 70.4%.

Next, 0.205 kg of pure water was added to 1.45 kg of the water dispersion sol to obtain a water dispersion sol having a solid concentration of 10% by weight, and 0.36 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was further added. Mix and stir for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 48.8 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and this water-dispersed sol was subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.) to 12,000 rpm. Then, the coarse particles having a particle diameter of 100 nm or more were classified and removed. As a result, 1.43 kg of an aqueous dispersion sol having a solid content of 3.5% by weight was obtained.

Next, 1.03 kg of pure water was mixed with 1.43 kg of the water-dispersed sol (solid content: 3.5 wt%) to obtain 2.50 kg of water-dispersed sol with a solid content of 2.0 wt%. Got. Next, the water dispersion zone Le autoclave (Taiatsu Co., 10L) placed in, 18 hours at a temperature of 165 ° C., and heat treatment.
Next, 0.10 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with the water dispersion sol taken out from the autoclave and cooled to room temperature, and stirred for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 6.6 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Further, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain a water-dispersed sol having a deionized solid content of 2.0% by weight. Thereby, 2.00 kg of an aqueous dispersion sol containing titanium-based fine particles (hereinafter referred to as “RCP-1”) obtained by firing and pulverizing the composite oxide particles and further classifying and removing coarse particles was obtained.

The water-dispersed sol containing titanium-based fine particles thus obtained was milky white and had a turbidity of 3.98 cm ⁻¹ . The average particle size of the titanium-based fine particles contained in the water-dispersed sol was 98 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 64.3%.
The titanium-based fine particles have a rutile-type crystal structure, and the specific surface area, X-ray diffraction crystallite diameter, crystal plane spacing and relative peak intensity ratio obtained from X-ray diffraction are determined by the composite oxidation. It showed the same value as the product particles (titanium-based particles before pulverization).
Furthermore, measurement of the content of the metal component contained in the titanium-based fine particles, in terms of oxide based on the respective metal components, TiO ₂ 83.9 wt%, SnO ₂ 10.4 wt%, SiO ₂ 5. 3 wt% and K ₂ O 0.4 wt%. The specific gravity of the titanium-based fine particles determined from the metal content was 4.21.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.529, 1.564, 1.604, 1.649, 1.701, 1.730. Further, the minimum value of the sum of squares of deviation obtained from the coating film refractive index Nav ′ and the coating volume refractive index Nav calculated from the volume fraction / weight fraction conversion formula and the Maxwell-Garnet formula is 0.000002. The refractive index of the particles showing the minimum value was 2.16. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.16. Incidentally, the refractive index of the titanium-based fine particles measured by the refractive index measurement method B (standard solution method) was 2.16.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[Comparative Example 2]
Preparation of water-dispersed sol containing titanium-based fine particles
In the same manner as in Reference Example 1, 0.63 kg of dry powder composed of composite oxide particles having an average particle diameter of about 2 μm was obtained.
0.63 kg of the dry powder of the composite oxide particles was fired for 1 hour at a temperature of 180 ° C. in an air atmosphere to obtain 0.59 kg of a fired powder of the composite oxide particles.
The composite oxide particles (titanium-based particles) obtained by firing in this way have a rutile crystal structure, a specific surface area of 212 m ² / g, and an X-ray diffraction crystallite diameter of 7. 1 nm. Further, the interplanar spacing of (310) crystal planes determined from X-ray diffraction was 0.1365 nm, and the interplanar spacing of (301) crystal planes was 0.1354 nm. Furthermore, as determined by X-ray diffraction, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ²⁾ was 24/100 .

Next, 0.17 kg of the calcined powder of the obtained composite oxide particles (titanium particles) was dispersed in 250.4 g of pure water, and 24.8 g of 10 wt% potassium hydroxide aqueous solution was added thereto. The pH was adjusted to 11.0. Next, 1.27 kg of quartz beads having a particle diameter of 0.1 to 0.2 mm (high-purity silica beads 015 manufactured by MRC Unitech Co., Ltd.) was added to this mixed aqueous solution, and this was mixed with a wet pulverizer (Kampe batch type tabletop sand mill). The composite oxide particles were pulverized for 180 minutes. Then, after separating and removing the quartz beads using a stainless steel filter having an opening of 44 μm, 840.0 g of pure water was further added and stirred, and 1.43 kg of an aqueous dispersion sol having a solid content of 11 wt% was added. Obtained.
The aqueous dispersion sol containing composite oxide fine particles obtained by pulverization in this way was milky white. The average particle size of the composite oxide fine particles contained in the water-dispersed sol was 130 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 68.2%.

Next, 0.14 kg of pure water was added to 1.43 kg of the water dispersion sol to obtain a water dispersion sol having a solid content concentration of 10 wt%, and 0.35 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation). Mix and stir for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 48.1 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, after the cation exchange resin was separated and removed using a 44 μm stainless steel filter, this water-dispersed sol was subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.) at 12,000 rpm. The treatment was carried out at a speed for 1 hour to classify and remove coarse particles having a particle diameter of 100 nm or more. As a result, 1.39 kg of an aqueous dispersion sol having a solid content of 5.2% by weight was obtained.

Next, 1.39 kg of the water-dispersed sol (solid content is 5.2% by weight) is mixed with 2.22 kg of pure water to obtain 3.61 kg of water-dispersed sol having a solid content of 2.0% by weight. Got. Next, this water-dispersed sol was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 10 L), and heat-treated at a temperature of 165 ° C. for 18 hours.
Next, 0.14 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with the water dispersion sol taken out from the autoclave and cooled to room temperature, and stirred for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 9.5 g of a cation exchange resin (Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Further, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain a water-dispersed sol having a deionized solid content of 2.0% by weight. Thus, 3.21 kg of an aqueous dispersion sol containing titanium-based fine particles (hereinafter referred to as “RCP-2”) obtained by firing and pulverizing the composite oxide particles and further classifying and removing coarse particles was obtained.

The aqueous dispersion sol containing titanium-based fine particles thus obtained was milky white and had a turbidity of 1.03 cm ⁻¹ . The average particle diameter of the titanium-based fine particles contained in the water-dispersed sol was 72 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 56.1%.
The titanium-based fine particles have a rutile-type crystal structure, and the specific surface area, X-ray diffraction crystallite diameter, crystal plane spacing and relative peak intensity ratio obtained from X-ray diffraction are determined by the composite oxidation. It showed the same value as the product particles (titanium-based particles before pulverization).
Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, TiO ₂ 84.4 wt%, SnO ₂ 9.9 wt%, SiO ₂ 5. 3 wt% and K ₂ O 0.4 wt%. The specific gravity of the titanium-based fine particles obtained from this metal content was 4.20.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.529, 1.564, 1.604, 1.649, 1.701, 1.730. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′ and the coating volume refractive index Nav calculated from the volume fraction / weight fraction conversion formula and the Maxwell-Garnet formula is 0.000002. The refractive index of the particles showing the minimum value was 2.17. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.17. Incidentally, the refractive index of the titanium-based fine particles measured by the refractive index measurement method B (standard solution method) was 2.17.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[Comparative Example 3]
Preparation of water-dispersed sol containing titanium-based fine particles
In the same manner as in Reference Example 1, 0.63 kg of dry powder composed of composite oxide particles having an average particle diameter of about 2 μm was obtained.
0.63 kg of the dry powder of the composite oxide particles was fired for 1 hour at a temperature of 850 ° C. in an air atmosphere to obtain 0.59 kg of a fired powder of the composite oxide particles.
The composite oxide particles (titanium-based particles) obtained by firing in this way have a rutile crystal structure, a specific surface area of 51 m ² / g, and an X-ray diffraction crystallite diameter of 28. It was 0 nm. Further, the interplanar spacing of (310) crystal planes determined from X-ray diffraction was 0.1456 nm, and the interplanar spacing of (301) crystal planes was 0.1361 nm. Furthermore, as determined by X-ray diffraction, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ²⁾ was 12/100 . An X-ray diffraction chart (XRD chart) obtained at this time is as shown in FIG.

Next, 0.17 kg of the calcined powder of the obtained composite oxide particles (titanium particles) was dispersed in 250.4 g of pure water, and 24.8 g of 10 wt% potassium hydroxide aqueous solution was added thereto. The pH was adjusted to 11.0. Next, 1.27 kg of quartz beads having a particle diameter of 0.1 to 0.2 mm (high-purity silica beads 015 manufactured by MRC Unitech Co., Ltd.) was added to this mixed aqueous solution, and this was mixed with a wet pulverizer (Kampe batch type tabletop sand mill). The composite oxide particles were pulverized for 180 minutes. Then, after separating and removing the quartz beads using a stainless steel filter having an opening of 44 μm, 840.0 g of pure water was further added and stirred, and 1.12 kg of an aqueous dispersion sol having a solid content of 11 wt% was added. Obtained.
The aqueous dispersion sol containing composite oxide fine particles obtained by pulverization in this way was milky white. The average particle size of the composite oxide fine particles contained in the water-dispersed sol was 150 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 82.6%.

Next, 0.11 kg of pure water was added to 1.12 kg of the water-dispersed sol to obtain a water-dispersed sol having a solid concentration of 10% by weight, and 0.28 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation). Mix and stir for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 37.7 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and this water-dispersed sol was subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.) to 12,000 rpm. Then, the coarse particles having a particle diameter of 100 nm or more were classified and removed. As a result, 1.12 kg of an aqueous dispersion sol having a solid content of 2.0% by weight was obtained.

Next, this water-dispersed sol was placed in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 5 L) and heat-treated at a temperature of 165 ° C. for 18 hours.
Next, 44.2 g of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with the water-dispersed sol taken out from the autoclave and cooled to room temperature, and stirred for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 2.9 g of a cation exchange resin (Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Further, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain a water-dispersed sol having a deionized solid content of 2.0% by weight. Thus, 1.07 kg of an aqueous dispersion sol containing titanium-based fine particles (hereinafter referred to as “RCP-3”) obtained by firing and pulverizing the composite oxide particles and further classifying and removing coarse particles was obtained.

The water-dispersed sol containing titanium-based fine particles thus obtained was milky white and had a turbidity of 4.82 cm ⁻¹ . The average particle diameter of the titanium-based fine particles contained in the water-dispersed sol was 111 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 76.9%.
The titanium-based fine particles have a rutile-type crystal structure, and the specific surface area, X-ray diffraction crystallite diameter, crystal plane spacing and relative peak intensity ratio obtained from X-ray diffraction are determined by the composite oxidation. It showed the same value as the product particles (titanium-based particles before pulverization).
Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, TiO ₂ 84.5% by weight, SnO ₂ 9.8% by weight, SiO ₂ 5. 3 wt% and K ₂ O 0.4 wt%. The specific gravity of the titanium-based fine particles obtained from this metal content was 4.20.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 55 wt%, 1.542, 1.591, 1.647, 1.719, 1.797, It was 1.842. Further, the minimum value of the sum of squares of deviation obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating film refractive index Nav calculated from the Maxwell-Garnet formula is 0.000048. The refractive index of the particles showing the minimum value was 2.58. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.58.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[Comparative Example 4]
Preparation of water-dispersed sol containing titanium-based fine particles
In the same manner as in Reference Example 1, 0.63 kg of dry powder composed of composite oxide particles having an average particle diameter of about 2 μm was obtained.
0.63 kg of the dry powder of the composite oxide particles was fired for 1 hour at a temperature of 600 ° C. in an air atmosphere to obtain 0.59 kg of a fired powder of the composite oxide particles.
The composite oxide particles (titanium-based particles) obtained by firing in this way have a rutile crystal structure, a specific surface area of 138 m ² / g, and an X-ray diffraction crystallite diameter of 8. It was 2 nm. Further, the interplanar spacing of (310) crystal planes determined from X-ray diffraction was 0.1452 nm, and the interplanar spacing of (301) crystal planes was 0.1357 nm. Furthermore, as determined by X-ray diffraction, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ²⁾ was 13/100 .

Next, 0.17 kg of the calcined powder of the obtained composite oxide particles (titanium particles) was dispersed in 250.4 g of pure water, and 24.8 g of 10 wt% potassium hydroxide aqueous solution was added thereto. The pH was adjusted to 11.0. Next, 1.27 kg of quartz beads having a particle diameter of 0.1 to 0.2 mm (high-purity silica beads 015 manufactured by MRC Unitech Co., Ltd.) was added to this mixed aqueous solution, and this was mixed with a wet pulverizer (Kampe batch type tabletop sand mill). The composite oxide particles were pulverized for 180 minutes. Then, after separating and removing the quartz beads using a stainless steel filter having an opening of 44 μm, 840.0 g of pure water was further added and stirred to obtain 1.19 kg of an aqueous dispersion sol having a solid content of 11% by weight. Got.
The aqueous dispersion sol containing composite oxide fine particles obtained by pulverization in this way was milky white. The average particle size of the composite oxide fine particles contained in the water-dispersed sol was 104 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 58.6%.

Next, 0.12 kg of pure water was added to 1.19 kg of the water-dispersed sol to obtain a water-dispersed sol having a solid concentration of 10% by weight, and 0.29 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation). Mix and stir for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 40.1 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a filter made of stainless steel having an aperture of 44 μm. However, this water-dispersed sol was not subjected to an operation for classifying coarse particles having a particle diameter of 100 nm or more using a centrifuge. As a result, 1.12 kg of an aqueous dispersion sol having a solid content of 10.0% by weight was obtained.

Next, 4.48 kg of pure water is mixed with 1.12 kg of the water-dispersed sol (solid content is 10.0% by weight) to obtain 5.60 kg of water-dispersed sol having a solid content of 2.0% by weight. Got. Next, this water-dispersed sol was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 10 L), and heat-treated at a temperature of 165 ° C. for 18 hours.
Next, 0.22 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with the aqueous dispersion sol taken out from the autoclave and cooled to room temperature, and stirred for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 14.8 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Further, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain a water-dispersed sol having a deionized solid content of 2.0% by weight. As a result, 5.49 kg of an aqueous dispersion sol containing titanium-based fine particles (hereinafter referred to as “RCP-4”) obtained by firing and pulverizing the composite oxide particles and further classifying and removing coarse particles was obtained.

The aqueous dispersion sol containing titanium-based fine particles thus obtained was milky white and had a turbidity of 10.25 cm ⁻¹ . The average particle diameter of the titanium-based fine particles contained in the water-dispersed sol was 104 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 58.6%.
The titanium-based fine particles have a rutile-type crystal structure, and the specific surface area, X-ray diffraction crystallite diameter, crystal plane spacing and relative peak intensity ratio obtained from X-ray diffraction are determined by the composite oxidation. It showed the same value as the product particles (titanium-based particles before pulverization).
Furthermore, measurement of the content of the metal component contained in the titanium-based fine particles, in terms of oxide based on the respective metal components, TiO ₂ 83.7 wt%, SnO ₂ 10.6 wt%, SiO ₂ 5. 4 was wt% and K ₂ O0.3% by weight. The specific gravity of the titanium-based fine particles determined from the metal content was 4.21.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.548, 1.594, 1.642, 1.699, 1.743, 1.785. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating film refractive index Nav calculated from the Maxwell-Garnet formula is 0.000664. The refractive index of the particles showing the minimum value was 2.38. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.38.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[Comparative Example 5]
Preparation of water-dispersed sol containing titanium-based fine particles Commercially available titanium oxide powder (fine particle titanium oxide MT-150W manufactured by Teika Co., Ltd.) was prepared. This titanium oxide powder had a rutile crystal structure, a specific surface area of 88 m ² / g, and an X-ray diffraction crystallite diameter of 16.8 nm. Further, the interplanar spacing of (310) crystal planes determined from X-ray diffraction was 0.1457 nm, and the interplanar spacing of (301) crystal planes was 0.1363 nm. Furthermore, as determined by X-ray diffraction, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ²⁾ was 9/100 .
Judging from these measurement results, the titanium oxide powder is considered to be a fired product fired at a relatively high temperature.

Next, 0.17 kg of the titanium oxide powder was dispersed in 250.4 g of pure water, and 24.8 g of 10 wt% potassium hydroxide aqueous solution was added thereto to adjust the pH to 11.0. Next, 1.27 kg of quartz beads having a particle diameter of 0.1 to 0.2 mm (high-purity silica beads 015 manufactured by MRC Unitech Co., Ltd.) was added to this mixed aqueous solution, and this was mixed with a wet pulverizer (Kampe batch type tabletop sand mill). The titanium oxide powder was pulverized for 180 minutes. Then, after separating and removing the quartz beads using a stainless steel filter having an opening of 44 μm, 840.0 g of pure water was further added and stirred, and 1.01 kg of an aqueous dispersion sol having a solid content of 11 wt% was added. Obtained.
The aqueous dispersion sol containing the pulverized particles of the titanium oxide powder thus obtained by pulverization was milky white. The average particle size of the composite oxide fine particles contained in the water-dispersed sol was 548 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 100%.

Next, 0.10 kg of pure water was added to 1.01 kg of the water dispersion sol to obtain a water dispersion sol having a solid concentration of 10% by weight, and 0.25 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation). Mix and stir for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 34.0 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, after separating and removing the cation exchange resin using a stainless steel filter having an opening of 44 μm, this water-dispersed sol is subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.) and 3,000 rpm. Then, coarse particles having a particle diameter of 100 nm or more were classified and removed. As a result, 0.95 kg of an aqueous dispersion sol having a solid content of 2.2% by weight was obtained.

Next, 0.10 kg of pure water was mixed with 0.95 kg of the water-dispersed sol (solid content 6.6% by weight) to obtain 1.05 kg of water-dispersed sol having a solid content of 2.0% by weight. Got. Next, this water-dispersed sol was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 5 L) and heat-treated at a temperature of 165 ° C. for 18 hours.
Next, 41.6 g of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with the water-dispersed sol taken out from the autoclave and cooled to room temperature, and stirred for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 2.8 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Further, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain a water-dispersed sol having a deionized solid content of 2.0% by weight. Thus, 0.97 kg of an aqueous dispersion sol containing titanium-based fine particles (hereinafter referred to as “RCP-5”) obtained by firing and pulverizing the composite oxide particles and further classifying and removing coarse particles was obtained.

The aqueous dispersion sol containing titanium-based fine particles thus obtained was milky white and had a turbidity of 15.31 cm ⁻¹ . The average particle size of the titanium-based fine particles contained in the water-dispersed sol was 384 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 100%.
The titanium-based fine particles have a rutile-type crystal structure, and the specific surface area, X-ray diffraction crystallite diameter, crystal plane spacing and relative peak intensity ratio obtained from X-ray diffraction are determined by the composite oxidation. It showed the same value as the product particles (titanium-based particles before pulverization).
Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, TiO _{2 was} 98.3% by weight, Al ₂ O _{3 was} 0.4% by weight, Na _{2 based on} the oxide conversion standard of each metal component. They were 0.5% by weight of O, 0.1% by weight of CaO, 0.1% by weight of SiO ₂ and 0.6% by weight of P ₂ O ₅ . The specific gravity of the titanium-based fine particles determined from the metal content was 4.25.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.548, 1.594, 1.642, 1.699, 1.743, 1.797. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating film refractive index Nav calculated from the Maxwell-Garnet formula is 0.000602. The refractive index of the particles showing the minimum value was 2.39. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.39.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[Comparative Example 6]
Preparation of water-dispersed sol containing titanium-based fine particles Commercially available titanium oxide powder containing aluminum in addition to titanium (Ishihara Sangyo Co., Ltd. ultra-fine titanium oxide, TTO-51 (A)) was prepared. This titanium oxide powder had a rutile crystal structure, a specific surface area of 98 m ² / g, and an X-ray diffraction crystallite diameter of 14.3 nm. Further, the interplanar spacing of the (310) crystal plane determined by X-ray diffraction was 0.1449 nm, and the interplanar spacing of the (301) crystal plane was 0.1357 nm. Furthermore, as determined by X-ray diffraction, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ²⁾ was 11/100 .
Judging from these measurement results, the titanium oxide powder is considered to be a fired product fired at a relatively high temperature.

Next, 0.17 kg of the titanium oxide powder was dispersed in 250.4 g of pure water, and 24.8 g of 10 wt% potassium hydroxide aqueous solution was added thereto to adjust the pH to 11.0. Next, 1.27 kg of quartz beads having a particle diameter of 0.1 to 0.2 mm (high-purity silica beads 015 manufactured by MRC Unitech Co., Ltd.) was added to this mixed aqueous solution, and this was mixed with a wet pulverizer (Kampe batch type tabletop sand mill). The titanium oxide powder was pulverized for 180 minutes. Then, after separating and removing the quartz beads using a stainless steel filter having an opening of 44 μm, 840.0 g of pure water was further added and stirred to obtain 1.09 kg of an aqueous dispersion sol having a solid content of 11% by weight. Obtained.
The aqueous dispersion sol containing the pulverized particles of the titanium oxide powder thus obtained by pulverization was milky white. The average particle size of the composite oxide fine particles contained in the water-dispersed sol was 690 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 100%.

Next, 0.205 kg of pure water was added to 1.09 kg of the water dispersion sol to obtain a water dispersion sol having a solid concentration of 10% by weight, and 0.287 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation). Mix and stir for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 36.7 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, after separating and removing the cation exchange resin using a stainless steel filter having an opening of 44 μm, this water-dispersed sol is subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.) and 3,000 rpm. Then, coarse particles having a particle diameter of 100 nm or more were classified and removed. As a result, 1.09 kg of an aqueous dispersion sol having a solid content of 2.5% by weight was obtained.

Next, 0.27 kg of pure water was mixed with 1.09 kg of the water-dispersed sol (solid content 2.5% by weight) to obtain 1.36 kg of water-dispersed sol having a solid content of 2.0% by weight. Got. Next, this water-dispersed sol was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 5 L) and heat-treated at a temperature of 165 ° C. for 18 hours.
Next, 54.2 g of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with the water dispersion sol taken out from the autoclave and cooled to room temperature, and stirred for 15 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and then 3.6 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Further, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain a water-dispersed sol having a deionized solid content of 2.0% by weight. Thereby, 1.30 kg of an aqueous dispersion sol containing titanium-based fine particles (hereinafter referred to as “RCP-6”) obtained by firing and pulverizing the composite oxide particles and further classifying and removing coarse particles was obtained.

The aqueous dispersion sol containing titanium-based fine particles thus obtained was milky white and had a turbidity of 12.22 cm ⁻¹ . The average particle size of the titanium-based fine particles contained in the water-dispersed sol was 298 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 100%.
The titanium-based fine particles have a rutile-type crystal structure, and the specific surface area, X-ray diffraction crystallite diameter, crystal plane spacing and relative peak intensity ratio obtained from X-ray diffraction are determined by the composite oxidation. It showed the same value as the product particles (titanium-based particles before pulverization).
Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, 85.2% by weight of TiO ₂ , 13.2% by weight of Al ₂ O ₃ , SiO _{2 based on} the oxide conversion standard of each metal component. was 1.4 wt% and P ₂ O ₅ 0.2 wt%. The specific gravity of the titanium-based fine particles determined from the metal content was 4.18.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.516, 1.541, 1.564, 1.593, 1.630, 1.648. Further, the minimum value of the sum of squares of deviation obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating refractive index Nav calculated from the Maxwell-Garnet formula is 0.000031. The refractive index of the particles showing the minimum value was 1.92. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 1.92. Incidentally, the refractive index of the titanium-based fine particles measured by the refractive index measurement method B (standard solution method) was 1.92.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[Example 6]
Preparation of water-dispersed sol containing metal oxide fine particles
The aqueous dispersion sol of titanium-based fine particles CP-1 prepared in the same manner as in Reference Example 1 (solid content: 2.0 wt%): 7.50 kg, 5.0 wt% ammonia water 57.0 g After mixing, when the weight of the titanium-based fine particles is represented by C and the weight of the coating layer is represented by S, the weight ratio (S / C) is 20/100 on an oxide conversion basis. 144.2 g of normal ethyl silicate (manufactured by Tama Chemical Industry Co., Ltd.) containing 28 wt% of silicon component in terms of SiO ₂ and methanol (Mayashi Junyaku Co., Ltd., methyl alcohol concentration: 99.9 wt%) 7 30 kg was mixed. Subsequently, this mixed solution was heated to a temperature of 50 ° C. and stirred for 18 hours.
Next, after cooling the obtained mixed solution to room temperature, methanol was removed using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013), and the dispersion medium was replaced with water. Further, it was concentrated to prepare an aqueous dispersion sol having a solid content of 20.0% by weight. As a result, 0.88 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “CSP-1”) obtained by coating the surface of the titanium-based fine particles with a hydrolyzed condensate of normal ethyl silicate, that is, silicon dioxide. Got.
The refractive index of the silicon dioxide formed by forming the coating layer of the metal oxide fine particles was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.

The water-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white, and its turbidity was 5.36 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 33 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 66.0% by weight of TiO ₂ , 8.1% by weight of SnO ₂ , SiO ₂ 25 based on the oxide conversion standard of each metal component. .7 was wt% and K ₂ O0.2% by weight. The specific gravity of the metal oxide fine particles determined from the metal content was 3.52.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10% by weight, 20% by weight, 30% by weight, 40% by weight, 50% by weight, and 55% by weight, 1.523, 1.551, 1.579, 1.619, 1.661, It was 1.685. Further, the minimum value of the sum of squares of deviation obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating film refractive index Nav calculated from the Maxwell-Garnet formula is 0.000013. The refractive index of the particles showing the minimum value was 2.04. Thereby, the refractive index of the metal oxide fine particles could be regarded as 2.04. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.04.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Example 7]
Preparation of aqueous zirconate peroxide solution 15.79 kg of zirconium oxychloride aqueous solution containing 2.0 wt% of zirconium oxychloride (manufactured by Taiyo Mining Co., Ltd.) in terms of ZrO ₂ , and 15.0 wt. Of ammonia. % Aqueous ammonia was gradually added under stirring to obtain a pH 8.5 slurry containing zirconium hydrate. Next, this slurry was filtered and then washed with pure water to obtain 3.00 kg of a 10.0% by weight cake based on ZrO _{2 as} a zirconium component.
Next, 1.35 kg of pure water was added to 150.0 g of this cake, and 90.0 g of a potassium hydroxide aqueous solution containing 10.0% by weight of potassium hydroxide (manufactured by Kanto Chemical Co., Ltd.) was added to make it alkaline. Then, 300.0 g of hydrogen peroxide containing 35.0% by weight of hydrogen peroxide was added and heated to a temperature of 50 ° C. to dissolve this cake. Further, 1.11 kg of pure water was added to obtain 3.00 kg of an aqueous zirconate peroxide solution containing 0.5% by weight of zirconate peroxide in terms of ZrO ₂ on a conversion basis. The pH of the aqueous zirconate peroxide solution was 12.

Preparation of silicic acid solution On the other hand, after 0.31 kg of commercially available water glass (manufactured by AGC S-Tech Co., Ltd.) was diluted with pure water, a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was used. The dealkalization was carried out to obtain 3.00 kg of an aqueous silicic acid solution containing 2.0% by weight of silicic acid on a SiO ₂ conversion basis. The silicic acid aqueous solution had a pH of 2.3.
Preparation of water-dispersed sol containing metal oxide fine particles
13.76 kg of pure water was added to 7.50 kg of an aqueous dispersion sol (solid content 2.0% by weight) of titanium-based fine particles CP-1 prepared by the same method as in Reference Example 1, and the mixture was stirred at 90 ° C. Then, 6.00 kg of the aqueous zirconate peroxide solution and 4.50 kg of the silicic acid aqueous solution were gradually added thereto, and after completion of the addition, the mixture was aged with stirring for 1 hour while maintaining the temperature at 90 ° C.
Next, this mixed solution was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 50 L) and subjected to heat treatment at a temperature of 165 ° C. for 18 hours.

Next, the obtained mixed solution is cooled to room temperature, and then concentrated using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013) to disperse in water with a solid content of 20.0% by weight. A sol was prepared.
Next, 0.59 kg of an anion exchange resin (Mitsubishi Chemical Corporation) was mixed with the obtained water dispersion sol and stirred for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 81.0 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain 1.32 kg of an aqueous dispersion sol having a solid content of 20.0% by weight.
As a result, 1.32 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “CSP-2”) obtained by coating the surface of the titanium-based fine particles with a composite oxide containing silicon and zirconium. .
The refractive index of the composite oxide formed by forming the coating layer of the metal oxide fine particles was 1.54, which is 0.81 lower than the refractive index of the titanium-based fine particles.

The aqueous dispersion sol containing the metal oxide fine particles thus obtained was transparent milky white, and its turbidity was 5.35 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 37 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, TiO ₂ 67.2% by weight, SnO ₂ 8.6% by weight, SiO ₂ 19 based on the oxide conversion standard of each metal component. .3 wt% and a ZrO ₂ 4.6 wt% and K ₂ O0.3% by weight. The specific gravity of the metal oxide fine particles determined from the metal content was 3.75.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. when m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.526, 1.560, 1.596, 1.638, 1.684, 1.710. Further, the minimum value of the sum of square deviations obtained from the coating film refractive index Nav ′ and the coating volume refractive index Nav calculated from the volume fraction / weight fraction conversion formula and the Maxwell-Garnet formula is 0.000009. The refractive index of the particles showing the minimum value was 2.07. Thereby, it could be considered that the refractive index of the metal oxide fine particles was 2.07. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.07.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Example 8]
Preparation of water-dispersed sol containing metal oxide fine particles
Water-dispersed sol of titanium-based fine particles CP-1 prepared by the same method as in Reference Example 1 (solid content: 2.0% by weight) 1.16 kg of pure water was added to 7.50 kg and stirred at 90 ° C. Then, 16.80 kg of an aqueous zirconate peroxide solution and 1.80 kg of an aqueous silicic acid solution prepared in the same manner as in Example 7 were gradually added thereto, and after the addition was completed, the temperature was 90 ° C. The mixture was aged for 1 hour with stirring.
Next, this mixed solution was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 50 L) and subjected to heat treatment at a temperature of 165 ° C. for 18 hours.
Next, the obtained mixed solution is cooled to room temperature, and then concentrated using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013) to disperse in water with a solid content of 20.0% by weight. A sol was prepared.
Next, 0.59 kg of an anion exchange resin (Mitsubishi Chemical Corporation) was mixed with the obtained water dispersion sol and stirred for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 81.0 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain 1.32 kg of an aqueous dispersion sol having a solid content of 20.0% by weight.
As a result, 1.32 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “CSP-3”) formed by coating the surface of the titanium-based fine particles with a composite oxide containing silicon and zirconium. .
The composite oxide formed by forming the metal oxide fine particle coating layer had a refractive index of 2.11 which was 0.24 lower than the refractive index of the titanium-based fine particles.

The water-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.34 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 31 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, TiO ₂ 65.9% by weight, SnO ₂ 8.0% by weight, SiO ₂ 12 based on the oxide conversion standard of each metal component. 0.0% by weight, 13.9% by weight of ZrO ₂ and 0.2% by weight of K ₂ O. The specific gravity of the metal oxide fine particles determined from the metal content was 4.06.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.529, 1.564, 1.604, 1.649, 1.701, 1.741. Further, the minimum value of the sum of square deviations obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating film refractive index Nav calculated from the Maxwell-Garnet formula is 0.000045. The refractive index of the particles showing the minimum value was 2.17. Thereby, it could be considered that the refractive index of the metal oxide fine particles was 2.21. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.17.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Example 9]
Preparation of water-dispersed sol containing metal oxide fine particles
A water-dispersed sol of titanium-based fine particles CP-1 prepared by the same method as in Reference Example 1 (solid content: 2.0% by weight) 18.29 kg of pure water was added to 7.50 kg and stirred at 90 ° C. After heating to a temperature of 5%, the aqueous solution of silicic acid 5.98 kg prepared in the same manner as in Example 7 and sodium aluminate containing 0.67% by weight of an aluminum component on an Al ₂ O ₃ conversion basis (Asahi Chemical Industry Co., Ltd.) 60.9 g (manufactured by Co., Ltd.) was gradually added, and after completion of addition, the mixture was aged with stirring for 1 hour while maintaining the temperature at 90 ° C.
Next, the obtained mixed solution is cooled to room temperature, and then concentrated using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013) to disperse in water with a solid content of 20.0% by weight. A sol was prepared.
Next, 0.59 kg of an anion exchange resin (Mitsubishi Chemical Corporation) was mixed with the obtained water dispersion sol and stirred for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 81.0 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain 1.32 kg of an aqueous dispersion sol having a solid content of 20.0% by weight.
As a result, 1.32 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “CSP-4”) obtained by coating the surface of the titanium-based fine particles with a composite oxide containing silicon and aluminum. .
The composite oxide formed by forming the metal oxide fine particle coating layer had a refractive index of 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.

The aqueous dispersion sol containing the metal oxide fine particles thus obtained was transparent milky white, and its turbidity was 5.35 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 32 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, TiO _{2 was} 70.9% by weight, SnO ₂ 8.9% by weight, SiO ₂ 19 based on the oxide conversion standard of each metal component. 0.8% by weight, 0.2% by weight of Al ₂ O _{3 and} 0.2% by weight of K ₂ O. The specific gravity of the metal oxide fine particles determined from the metal content was 3.70.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10% by weight, 20% by weight, 30% by weight, 40% by weight, 50% by weight, and 55% by weight, 1.528, 1.561, 1.598, 1.639, 1.485, 1.712. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating film refractive index Nav calculated from the Maxwell-Garnet formula is 0.000047. The refractive index of the particles showing the minimum value was 2.07. Thereby, it could be considered that the refractive index of the metal oxide fine particles was 2.07. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.08.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Example 10]
Preparation of water-dispersed sol containing metal oxide fine particles
The aqueous dispersion sol of titanium-based fine particles CP-1 prepared in the same manner as in Reference Example 2 (solid content: 2.0% by weight): 7.50 kg and 57.0 g of 5.0% by weight ammonia water. After mixing, when the weight of the titanium-based fine particles is represented by C and the weight of the coating layer is represented by S, the weight ratio (S / C) is 20/100 on an oxide conversion basis. 144.2 g of normal ethyl silicate (manufactured by Tama Chemical Industry Co., Ltd.) containing 28 wt% of silicon component in terms of SiO ₂ and methanol (Mayashi Junyaku Co., Ltd., methyl alcohol concentration: 99.9 wt%) 7 30 kg was mixed. Subsequently, this mixed solution was heated to a temperature of 50 ° C. and stirred for 18 hours.
Next, after cooling the obtained mixed solution to room temperature, methanol was removed using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013), and the dispersion medium was replaced with water. Further, it was concentrated to prepare an aqueous dispersion sol having a solid content of 20.0% by weight. As a result, 0.89 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “CSP-5”) obtained by coating the surface of the titanium-based fine particles with a hydrolyzed condensate of normal ethyl silicate, that is, silicon dioxide. Got.
The refractive index of the silicon dioxide formed by forming the coating layer of the metal oxide fine particles was 1.45, 0.93 lower than the refractive index of the titanium-based fine particles.

The aqueous dispersion sol containing the metal oxide fine particles thus obtained was transparent milky white, and its turbidity was 5.47 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 37 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, TiO ₂ 78.0% by weight, SnO ₂ 8.8% by weight, SiO ₂ 20 in terms of oxide conversion standards of each metal component. And 2% by weight and 0.2% by weight K ₂ O. The specific gravity of the metal oxide fine particles determined from the metal content was 3.68.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.530, 1.566, 1.604, 1.650, 1.702, 1.730. Further, the minimum value of the sum of square deviations obtained from the coating film refractive index Nav ′ and the coating volume refractive index Nav calculated from the volume fraction / weight fraction conversion formula and the Maxwell-Garnet formula is 0.000009. The refractive index of the particles showing the minimum value was 2.12. Accordingly, the refractive index of the metal oxide fine particles could be regarded as 2.12. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.11.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Example 11]
Preparation of water-dispersed sol containing metal oxide fine particles
The aqueous dispersion sol of titanium-based fine particles CP-3 prepared in the same manner as in Reference Example 3 (solid content: 2.0% by weight): 7.50 kg, 5.0% by weight of aqueous ammonia 57.0 g After mixing, when the weight of the titanium-based fine particles is represented by C and the weight of the coating layer is represented by S, the weight ratio (S / C) is 20/100 on an oxide conversion basis. 144.2 g of normal ethyl silicate (manufactured by Tama Chemical Industry Co., Ltd.) containing 28 wt% of silicon component in terms of SiO ₂ and methanol (Mayashi Junyaku Co., Ltd., methyl alcohol concentration: 99.9 wt%) 7 30 kg was mixed. Subsequently, this mixed solution was heated to a temperature of 50 ° C. and stirred for 18 hours.
Next, after cooling the obtained mixed solution to room temperature, methanol was removed using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013), and the dispersion medium was replaced with water. Further, it was concentrated to prepare an aqueous dispersion sol having a solid content of 20.0% by weight. As a result, 0.89 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “CSP-6”) obtained by coating the surface of the titanium-based fine particles with a hydrolyzed condensate of normal ethyl silicate, that is, silicon dioxide. Got.
The refractive index of the silicon dioxide formed by forming the coating layer of the metal oxide fine particles was 1.45, 0.84 lower than the refractive index of the titanium-based fine particles.

The water-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.25 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 31 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 66.3% by weight of TiO ₂ , 8.1% by weight of SnO ₂ , SiO ₂ 25 based on the oxide conversion standard of each metal component. .4 was wt% and K ₂ O0.2% by weight. The specific gravity of the metal oxide fine particles determined from the metal content was 3.53.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10% by weight, 20% by weight, 30% by weight, 40% by weight, 50% by weight, and 55% by weight, 1.528, 1.560, 1.591, 1.631, 1.673, 1.696. Furthermore, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating refractive index Nav calculated from the Maxwell-Garnet formula is 0.000011. The refractive index of the particles showing the minimum value was 2.01. Thereby, the refractive index of the metal oxide fine particles was considered to be 2.01. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.01.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Example 12]
Preparation of water-dispersed sol containing metal oxide fine particles
Aqueous dispersion sol (solid content 2.0% by weight) 7.50 kg of titanium-based fine particles CP-4 prepared by the same method as in Reference Example 4 and 57.0 g of 5.0% by weight ammonia water. After mixing, when the weight of the titanium-based fine particles is represented by C and the weight of the coating layer is represented by S, the weight ratio (S / C) is 20/100 on an oxide conversion basis. 144.2 g of normal ethyl silicate (manufactured by Tama Chemical Industry Co., Ltd.) containing 28 wt% of silicon component in terms of SiO ₂ and methanol (Mayashi Junyaku Co., Ltd., methyl alcohol concentration: 99.9 wt%) 7 30 kg was mixed. Subsequently, this mixed solution was heated to a temperature of 50 ° C. and stirred for 18 hours.
Next, after cooling the obtained mixed solution to room temperature, methanol was removed using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013), and the dispersion medium was replaced with water. Further, it was concentrated to prepare an aqueous dispersion sol having a solid content of 20.0% by weight. As a result, 0.88 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “CSP-7”) obtained by coating the surface of the titanium-based fine particles with a hydrolyzed condensate of normal ethyl silicate, that is, silicon dioxide. Got.
The refractive index of the silicon dioxide formed by forming the coating layer of the metal oxide fine particles was 1.45, 0.98 lower than the refractive index of the titanium-based fine particles.

The water-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.46 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 41 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 66.1% by weight of TiO ₂ , 8.1% by weight of SnO ₂ , SiO ₂ 25 based on the oxide conversion standard of each metal component. .6 was wt% and K ₂ O0.2% by weight. The specific gravity of the metal oxide fine particles determined from the metal content was 3.52.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.530, 1.565, 1.601, 1.649, 1.699, 1.725. Further, the minimum value of the square sum of deviations obtained from the coating film refractive index Nav ′ and the coating volume refractive index Nav calculated from the volume fraction / weight fraction conversion formula and the Maxwell-Garnet formula is 0.000027. The refractive index of the particles showing the minimum value was 2.09. Thereby, it could be considered that the refractive index of the metal oxide fine particles was 2.09. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.09.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Example 13]
Preparation of water-dispersed sol containing metal oxide fine particles
An aqueous dispersion sol of titanium-based fine particles CP-5 prepared in the same manner as in Reference Example 5 (solid content: 2.0% by weight) 1.16 kg of pure water was added to 7.50 kg and stirred at 90 ° C. Then, 22.80 kg of zirconate aqueous solution and 0.30 kg of silicic acid aqueous solution prepared in the same manner as in Example 7 were gradually added thereto, and after addition was completed, the temperature was 90 ° C. The mixture was aged for 1 hour with stirring.
Next, this mixed solution was put in an autoclave (manufactured by Pressure Glass Industrial Co., Ltd., 50 L) and subjected to heat treatment at a temperature of 165 ° C. for 18 hours.
Next, the obtained mixed solution is cooled to room temperature, and then concentrated using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013) to disperse in water with a solid content of 20.0% by weight. A sol was prepared.
Next, 0.59 kg of an anion exchange resin (Mitsubishi Chemical Corporation) was mixed with the obtained water dispersion sol and stirred for 15 minutes. Next, after separating and removing the anion exchange resin using a stainless steel filter having an opening of 44 μm, 81.0 g of a cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed and stirred for 15 minutes. Next, the cation exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm to obtain 1.32 kg of an aqueous dispersion sol having a solid content of 20.0% by weight.
As a result, 1.32 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “CSP-8”) obtained by coating the surface of the titanium-based fine particles with a composite oxide containing silicon and zirconium. .
The composite oxide formed by forming the metal oxide fine particle coating layer had a refractive index of 2.11 which was 0.51 lower than the refractive index of the titanium-based fine particles.

The water-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.63 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 41 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 66.5% by weight of TiO ₂ , 8.3% by weight of SnO ₂ , SiO ₂ 6 based on the oxide conversion standard of each metal component. 0.2% by weight, 18.8% by weight of ZrO ₂ and 0.2% by weight of K ₂ O. The specific gravity of the metal oxide fine particles determined from the metal content was 4.34.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.534, 1.573, 1.619, 1.671, 1.731, 1.764. Further, the minimum value of the sum of squared deviations obtained from the coating film refractive index Nav ′ and the coating volume refractive index Nav calculated from the volume fraction / weight fraction conversion formula and the Maxwell-Garnet formula is 0.000014. The refractive index of the particles showing the minimum value was 2.31. Thereby, the refractive index of the metal oxide fine particles could be regarded as 2.31. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.30.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Comparative Example 7]
Preparation of water-dispersed sol containing metal oxide fine particles Water-dispersed sol of titanium-based fine particles RCP-1 prepared in the same manner as in Comparative Example 1 (solid content: 2.0 wt%) 7. After mixing 57.0 g of 5.0 wt% ammonia water in 50 kg, the weight of the titanium fine particles is represented by C, and the weight of the coating layer is represented by S, and the weight ratio (S / 144.2 g of normal ethyl silicate (manufactured by Tama Chemical Co., Ltd.) containing 28% by weight of a silicon component on a SiO ₂ conversion basis and methanol (Hayashi Junyaku ( Co., Ltd., methyl alcohol concentration: 99.9% by weight) and 7.30 kg. Subsequently, this mixed solution was heated to a temperature of 50 ° C. and stirred for 18 hours.
Next, after cooling the obtained mixed solution to room temperature, methanol was removed using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013), and the dispersion medium was replaced with water. Further, it was concentrated to prepare an aqueous dispersion sol having a solid content of 20.0% by weight. Thus, 0.90 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “RCSP-1”) obtained by coating the surface of the titanium-based fine particles with a hydrolyzed condensate of normal ethyl silicate, that is, silicon dioxide. Got.
The refractive index of the silicon dioxide formed by forming the coating layer of the metal oxide fine particles was 1.45, which is 0.71 lower than the refractive index of the titanium-based fine particles.

The water-dispersed sol containing the metal oxide fine particles thus obtained was milky white and had a turbidity of 8.93 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 99 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 59.4%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 66.2% by weight of TiO ₂ , 8.1% by weight of SnO ₂ , SiO ₂ 25 based on the oxide conversion standard of each metal component. .5 was wt% and K ₂ O0.2% by weight. The specific gravity of the metal oxide fine particles determined from the metal content was 3.52.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.522, 1.553, 1.587, 1.623, 1.661, It was 1.685. Further, the minimum value of the sum of square deviations obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating film refractive index Nav calculated from the Maxwell-Garnet formula is 0.000024. The refractive index of the particles showing the minimum value was 1.97. Thereby, the refractive index of the metal oxide fine particles could be regarded as 1.97. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 1.98.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Comparative Example 8]
Preparation of water-dispersed sol containing metal oxide fine particles Water-dispersed sol of titanium-based fine particles RCP-2 prepared in the same manner as in Comparative Example 2 (solid content: 2.0% by weight) 7. After mixing 57.0 g of 5.0 wt% ammonia water in 50 kg, the weight of the titanium fine particles is represented by C, and the weight of the coating layer is represented by S, and the weight ratio (S / 144.2 g of normal ethyl silicate (manufactured by Tama Chemical Co., Ltd.) containing 28% by weight of a silicon component on a SiO ₂ conversion basis and methanol (Hayashi Junyaku ( Co., Ltd., methyl alcohol concentration: 99.9% by weight) and 7.30 kg. Subsequently, this mixed solution was heated to a temperature of 50 ° C. and stirred for 18 hours.
Next, after cooling the obtained mixed solution to room temperature, methanol was removed using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013), and the dispersion medium was replaced with water. Further, it was concentrated to prepare an aqueous dispersion sol having a solid content of 20.0% by weight. Thus, 0.90 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “RCSP-2”) obtained by coating the surface of the titanium-based fine particles with hydrolyzed condensate of normal ethyl silicate, that is, silicon dioxide. Got.
The refractive index of the silicon dioxide formed by forming the coating layer of the metal oxide fine particles was 1.45, which is 0.72 lower than the refractive index of the titanium-based fine particles.

The aqueous dispersion sol containing the metal oxide fine particles thus obtained was milky white and had a turbidity of 6.03 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 73 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 49.2%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 66.0% by weight of TiO ₂ , 8.1% by weight of SnO ₂ , SiO ₂ 25 based on the oxide conversion standard of each metal component. .7 was wt% and K ₂ O0.2% by weight. The specific gravity of the metal oxide fine particles determined from the metal content was 3.52.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.522, 1.553, 1.590, 1.625, 1.670, It was 1.692. Further, the minimum value of the sum of squares of deviation obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating film refractive index Nav calculated from the Maxwell-Garnet formula is 0.000075. The refractive index of the particles showing the minimum value was 1.99. Thereby, the refractive index of the metal oxide fine particle titanium-based fine particles could be regarded as 1.99. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 1.98.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Comparative Example 9]
Preparation of water-dispersed sol containing metal oxide fine particles Water-dispersed sol of titanium-based fine particles RCP-3 prepared in the same manner as in Comparative Example 3 (solid content: 2.0% by weight) 7. After mixing 57.0 g of 5.0 wt% ammonia water in 50 kg, the weight of the titanium fine particles is represented by C, and the weight of the coating layer is represented by S, and the weight ratio (S / 144.2 g of normal ethyl silicate (manufactured by Tama Chemical Co., Ltd.) containing 28% by weight of a silicon component on a SiO ₂ conversion basis and methanol (Hayashi Junyaku ( Co., Ltd., methyl alcohol concentration: 99.9% by weight) and 7.30 kg. Subsequently, this mixed solution was heated to a temperature of 50 ° C. and stirred for 18 hours.
Next, after cooling the obtained mixed solution to room temperature, methanol was removed using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013), and the dispersion medium was replaced with water. Further, it was concentrated to prepare an aqueous dispersion sol having a solid content of 20.0% by weight. Accordingly, 0.88 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “RCSP-3”) obtained by coating the surface of the titanium-based fine particles with a hydrolyzed condensate of normal ethyl silicate, that is, silicon dioxide. Got.
The refractive index of the silicon dioxide formed by forming the coating layer of the metal oxide fine particles was 1.45, which is 1.13 lower than the refractive index of the titanium-based fine particles.

The water-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white, and its turbidity was 10.64 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 116 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 77.2%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 66.3% by weight of TiO ₂ , 8.1% by weight of SnO ₂ , SiO ₂ 25 based on the oxide conversion standard of each metal component. .4 was wt% and K ₂ O0.2% by weight. The specific gravity of the metal oxide fine particles determined from the metal content was 3.53.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.535, 1.580, 1.628, 1.681, 1.742, 1.777. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′ and the coating volume refractive index Nav calculated from the volume fraction / weight fraction conversion formula and the Maxwell-Garnet formula is 0.000023. The refractive index of the particles showing the minimum value was 2.24. Thereby, the refractive index of the metal oxide fine particles could be regarded as 2.24. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.23.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Comparative Example 10]
Preparation of water-dispersed sol containing metal oxide fine particles Water-dispersed sol of titanium-based fine particles RCP-4 prepared in the same manner as in Comparative Example 4 (solid content: 2.0% by weight) 7. After mixing 57.0 g of 5.0 wt% ammonia water in 50 kg, the weight of the titanium fine particles is represented by C, and the weight of the coating layer is represented by S, and the weight ratio (S / 144.2 g of normal ethyl silicate (manufactured by Tama Chemical Co., Ltd.) containing 28% by weight of a silicon component on a SiO ₂ conversion basis and methanol (Hayashi Junyaku ( Co., Ltd., methyl alcohol concentration: 99.9% by weight) and 7.30 kg. Subsequently, this mixed solution was heated to a temperature of 50 ° C. and stirred for 18 hours.
Next, after cooling the obtained mixed solution to room temperature, methanol was removed using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013), and the dispersion medium was replaced with water. Further, it was concentrated to prepare an aqueous dispersion sol having a solid content of 20.0% by weight. Thus, 0.87 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “RCSP-4”) obtained by coating the surface of the titanium-based fine particles with a hydrolyzed condensate of normal ethyl silicate, that is, silicon dioxide. Got.
The refractive index of the silicon dioxide formed by forming the coating layer of the metal oxide fine particles was 1.45, 0.93 lower than the refractive index of the titanium-based fine particles.

The aqueous dispersion sol containing the metal oxide fine particles thus obtained was milky white and had a turbidity of 16.21 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 106 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 58.1%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 66.3% by weight of TiO ₂ , 8.1% by weight of SnO ₂ , SiO ₂ 25 based on the oxide conversion standard of each metal component. .4 was wt% and K ₂ O0.2% by weight. The specific gravity of the metal oxide fine particles determined from the metal content was 3.53.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.530, 1.565, 1.601, 1.649, 1.699, 1.725. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′ and the coating volume refractive index Nav calculated from the volume fraction / weight fraction conversion formula and the Maxwell-Garnet formula is 0.000023. The refractive index of the particles showing the minimum value was 2.05. Thereby, it could be considered that the refractive index of the metal oxide fine particles was 2.05. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.05.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Comparative Example 11]
Preparation of water-dispersed sol containing metal oxide fine particles Water-dispersed sol of titanium-based fine particles RCP-5 prepared in the same manner as in Comparative Example 5 (solid content: 2.0% by weight) 7. After mixing 57.0 g of 5.0 wt% ammonia water in 50 kg, the weight of the titanium fine particles is represented by C, and the weight of the coating layer is represented by S, and the weight ratio (S / 144.2 g of normal ethyl silicate (manufactured by Tama Chemical Co., Ltd.) containing 28% by weight of a silicon component on a SiO ₂ conversion basis and methanol (Hayashi Junyaku ( Co., Ltd., methyl alcohol concentration: 99.9% by weight) and 7.30 kg. Subsequently, this mixed solution was heated to a temperature of 50 ° C. and stirred for 18 hours.
Next, after cooling the obtained mixed solution to room temperature, methanol was removed using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013), and the dispersion medium was replaced with water. Further, it was concentrated to prepare an aqueous dispersion sol having a solid content of 20.0% by weight. As a result, 0.88 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “RCSP-5”) obtained by coating the surface of the titanium-based fine particles with a hydrolyzed condensate of normal ethyl silicate, that is, silicon dioxide. Got.
The refractive index of the silicon dioxide formed by forming the coating layer of the metal oxide fine particles was 1.45, which is 1.25 lower than the refractive index of the titanium-based fine particles.

The aqueous dispersion sol containing the metal oxide fine particles thus obtained was milky white and had a turbidity of 21.29 cm ⁻¹ . The average particle size of the metal oxide fine particles contained in the water-dispersed sol was 387 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 100%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 79.8% by weight of TiO ₂ and 20.2% by weight of SiO _{2 on} the oxide conversion standard of each metal component. The specific gravity of the metal oxide fine particles determined from the metal content was 3.58.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.527, 1.561, 1.597, 1.638, 1.684, 1.710. Further, the minimum value of the sum of square deviations obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula, and the coating film refractive index Nav calculated from the Maxwell-Garnet formula is 0.000006. The refractive index of the particles showing the minimum value was 2.05. Thereby, it could be considered that the refractive index of the metal oxide fine particles was 2.05. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.05.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Comparative Example 12]
Preparation of water-dispersed sol containing metal oxide fine particles Water-dispersed sol of titanium-based fine particles RCP-6 prepared in the same manner as in Comparative Example 6 (solid content: 2.0% by weight) 7. After mixing 57.0 g of 5.0 wt% ammonia water in 50 kg, the weight of the titanium fine particles is represented by C, and the weight of the coating layer is represented by S, and the weight ratio (S / 144.2 g of normal ethyl silicate (manufactured by Tama Chemical Co., Ltd.) containing 28% by weight of a silicon component on a SiO ₂ conversion basis and methanol (Hayashi Junyaku ( Co., Ltd., methyl alcohol concentration: 99.9% by weight) and 7.30 kg. Subsequently, this mixed solution was heated to a temperature of 50 ° C. and stirred for 18 hours.
Next, after cooling the obtained mixed solution to room temperature, methanol was removed using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013), and the dispersion medium was replaced with water. Further, it was concentrated to prepare an aqueous dispersion sol having a solid content of 20.0% by weight. Thus, 0.88 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “RCSP-6”) obtained by coating the surface of the titanium-based fine particles with a hydrolyzed condensate of normal ethyl silicate, that is, silicon dioxide. Got.
The refractive index of the silicon dioxide formed by forming the coating layer of the metal oxide fine particles was 1.45, which is 0.52 lower than the refractive index of the titanium-based fine particles.

The aqueous dispersion sol containing the metal oxide fine particles thus obtained was milky white and its turbidity was 18.01 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 300 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 100%.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, TiO ₂ 64.8% by weight, SiO ₂ 20.1% by weight, and Al ₂ O in terms of oxide conversion standard of each metal component. ₃ 15.1 wt%. The specific gravity of the metal oxide fine particles determined from the metal content was 3.55.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.513, 1.531, 1.543, 1.569, 1.591, It was 1.603. Furthermore, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′ and the coating volume refractive index Nav calculated from the volume fraction / weight fraction conversion formula and the Maxwell-Garnet formula is 0.000043. The refractive index of the particles showing the minimum value was 1.76. Thereby, it could be considered that the refractive index of the metal oxide fine particles was 1.76. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 1.75.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Comparative Example 13]
Preparation of water-dispersed sol containing metal oxide fine particles
An aqueous dispersion sol (solid content 2.0% by weight) of 7.50 kg of titanium-based fine particles CP-1 prepared by the same method as in Reference Example 1 was added to an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP). -1013) to prepare an aqueous dispersion sol having a solid content of 20.0% by weight. As a result, 1.32 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “RCSP-7”) in which the surface of the titanium-based fine particles is not coated with silica-based oxide or silica-based composite oxide. It was.
The water-dispersed sol containing the metal oxide fine particles (titanium-based fine particles) thus obtained was transparent milky white and had a turbidity of 6.57 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 31 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
Furthermore, the content of the metal component contained in the metal oxide fine particles is 84.4% by weight of TiO ₂ and SnO ₂ 9.9 based on the oxide conversion standard of each metal component, similar to the titanium fine particles CP-1. Wt%, SiO ₂ 5.3 wt% and K ₂ O 0.4 wt%. The specific gravity of the metal oxide fine particles determined from the metal content was 4.20.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.544, 1.584, 1.630, 1.683, 1.743, 1.775. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula and the coating refractive index Nav calculated from the Maxwell-Garnet formula is 0.000167. The refractive index of the particles showing the minimum value was 2.35. Thereby, it could be considered that the refractive index of the metal oxide fine particles was 2.35.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Comparative Example 14]
Preparation of water-dispersed sol containing metal oxide fine particles
An aqueous dispersion sol (solid content 2.0% by weight) 7.50 kg of titanium-based fine particles CP-2 prepared by the same method as in Reference Example 2 was added to an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP). -1013) to prepare an aqueous dispersion sol having a solid content of 20% by weight. As a result, 1.31 kg of an aqueous dispersion sol containing metal oxide fine particles (hereinafter referred to as “RCSP-8”) in which the surface of the titanium-based fine particles is not coated with silica-based oxide or silica-based composite oxide. It was.
The water-dispersed sol containing the metal oxide fine particles (titanium fine particles) thus obtained was transparent milky white and had a turbidity of 6.63 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the water-dispersed sol was 35 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%.
Furthermore, the content of the metal component contained in the metal oxide fine particles is 88.5% by weight of TiO ₂ and SnO ₂ 11 in terms of the oxide conversion standard of each metal component, similar to the titanium-based fine particles CP-2. 0.1% by weight and 0.4% by weight of K ₂ O. The specific gravity of the metal oxide fine particles determined from the metal content was 4.44.
The coating film refractive index Nav ′ measured using a spectroscopic ellipsometer based on the method described in the above “Particle Refractive Index Measurement Method A” is a weight fraction of particles contained in the coating composition. When m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.532, 1.598, 1.622, 1.681, 1.746, 1.783. Further, the minimum value of the deviation sum of squares obtained from the coating film refractive index Nav ′, the volume fraction / weight fraction conversion formula and the coating refractive index Nav calculated from the Maxwell-Garnet formula is 0.000421. The refractive index of the particles showing the minimum value was 2.38. Thereby, it could be considered that the refractive index of the metal oxide fine particles was 2.38.
Among the above measurement results, main data related to the present invention are shown in Table 2.

[Example 14 and Comparative Example 15]
Metal oxide fine particles CSP-1, CSP-2, CSP-3, CSP-4, CSP-5, CSP-6, CSP-7 or CSP-8 prepared by the same method as in Examples 6 to 13 are included. Each water dispersion sol, and metal oxide fine particles RCSP-1, RCSP-2, RCSP-3, RCSP-4, RCSP-5, RCSP-6, RCSP-7 prepared by the same method as Comparative Examples 7-14 Alternatively, each water-dispersed sol containing RCSP-8 is subjected to the above-mentioned “photocatalytic activity test of particles”, and the degree of photocatalytic activity possessed by each metal oxide fine particle contained in these water-dispersed sols is determined. Evaluation was based on the fading change rate of the sunset yellow dye used in the test. The evaluation results are shown in Table 3.
As a result, it was found that each metal oxide fine particle contained in the water-dispersed sol of the example had considerably lower photocatalytic activity than each metal oxide fine particle contained in the water-dispersed sol of the comparative example. Therefore, the coating film obtained by preparing a coating liquid for forming a curable coating film using the water-dispersed sol according to the present invention as a starting material and applying it to a plastic substrate or the like has excellent weather resistance. It was recognized that it would be.

[Example 15 and Comparative Example 16]
Metal oxide fine particles CSP-1, CSP-2, CSP-3, CSP-4, CSP-5, CSP-6, CSP-7 or CSP-8 prepared by the same method as in Examples 6 to 13 are included. Each water-dispersed sol, and metal oxide fine particles RCSP-1, RCSP-2, RCSP-3, RCSP-4, RCSP-5, RCSP-6, RCSP-7 prepared by the same method as Comparative Examples 7-14 Alternatively, each water-dispersed sol containing RCSP-8 is subjected to the above-mentioned “light resistance test of particles” to determine the degree of blue discoloration (blueing) of each metal oxide fine particle contained in these water-dispersed sols. Evaluation was made in relation to the irradiation time of ultraviolet rays used in the test. The evaluation results are shown in Table 4.
As a result, it was found that each metal oxide fine particle contained in the water-dispersed sol of the example was less likely to cause blue discoloration than each metal oxide fine particle contained in the water-dispersed sol of the comparative example. Therefore, the coating film obtained by preparing a coating liquid for forming a curable coating film using the water-dispersed sol according to the present invention as a starting material and applying it to a plastic substrate or the like is excellent in light resistance. It was recognized that it would be.

[Example 16]
Preparation of methanol-dispersed sol containing metal oxide fine particles Metal oxide fine particles CSP-1, CSP-2, CSP-3, CSP-4, CSP-5, CSP- prepared by the same method as in Examples 6-13. 6. 7.00 kg of methanol solution in which 134.6 g of tetraethoxysilane (manufactured by Tama Chemical Co., Ltd.) as a surface treatment agent was dissolved in 7.00 kg of each water dispersion sol containing CSP-7 or CSP-8. Was added with stirring and then heated at a temperature of 50 ° C. for 6 hours.
Next, these mixed solutions are cooled to room temperature, and then the dispersion medium is changed from water to methanol (manufactured by Hayashi Junyaku Co., Ltd.) using an ultrafiltration membrane device (filter membrane manufactured by Asahi Kasei Co., Ltd., SIP-1013). , Methyl alcohol concentration: 99.9% by weight). As a result, the solid content concentration contained in each methanol dispersion obtained from this was about 10.9% by weight, and the water content was about 0.3% by weight.
Furthermore, these methanol dispersion liquids were concentrated using an ultrafiltration membrane device, respectively, to obtain metal oxide fine particles CSP-1, CSP-2, CSP-3, CSP-4 having a solid content of 20% by weight, 0.70 kg of methanol dispersion sol containing CSP-5, CSP-6, CSP-7 or CSP-8 was prepared.
The appearance and turbidity of the methanol-dispersed sol containing the metal oxide fine particles thus obtained were as shown in Table 5.

[Example 17]
Preparation of PGM-dispersed sol containing metal oxide fine particles 0.70 kg of each methanol-dispersed sol containing metal oxide fine particles CSP-1, CSP-2 or CSP-5 prepared in the same manner as in Example 16, respectively. Into a flask of an evaporator (R-124 manufactured by BUCHI), 0.56 kg of propylene glycol monomethyl ether (PGM) is further placed in the flask.
Next, when the rotary evaporator is driven and the flask is rotated at a speed of 50 rpm under a reduced pressure condition of a temperature of 60 ° C. and a pressure of −0.035 MPa, the organic solvent (that is, methanol) used above evaporates. As it came, it was cooled and discharged out of the system.
This operation was continued for 1 hour to obtain PGM dispersion sols in which methanol contained in the methanol dispersion sol was substituted with propylene glycol monomethyl ether (PGM). Further, by adjusting the content of propylene glycol monomethyl ether (PGM), 0.56 kg of PGM dispersion sol containing metal oxide fine particles CSP-1, CSP-2 or CSP-5 having a solid content of 20% by weight Each was prepared.
The appearance and turbidity of the PGM-dispersed sol containing the metal oxide fine particles obtained in this manner were as shown in Table 5.

[Comparative Example 17]
Preparation of methanol-dispersed sol containing metal oxide fine particles Metal oxide fine particles RCSP-1, RCSP-2, RCSP-3, RCSP-4, RCSP-5, RCSP- prepared by the same method as Comparative Examples 7-14 6, 7.00 kg of methanol solution in which 134.6 g of tetraethoxysilane (manufactured by Tama Chemical Co., Ltd.) as a surface treatment agent was dissolved in 7.00 kg of each water dispersion sol containing RCSP-7 or RCSP-8. Was added with stirring and then heated at a temperature of 50 ° C. for 6 hours.
Next, these mixed solutions are cooled to room temperature, and then the dispersion medium is changed from water to methanol (manufactured by Hayashi Junyaku Co., Ltd.) using an ultrafiltration membrane device (filter membrane manufactured by Asahi Kasei Co., Ltd., SIP-1013). , Methyl alcohol concentration: 99.9% by weight). As a result, the solid content concentration contained in each of the obtained methanol dispersions was about 10.9% by weight, and the water content was 0.3% by weight.
Furthermore, these methanol dispersion liquids were concentrated using an ultrafiltration membrane device, respectively, to obtain metal oxide fine particles RCSP-1, RCSP-2, RCSP-3, RCSP-4 having a solid content of 20% by weight, 0.70 kg of methanol-dispersed sol containing RCSP-5, RCSP-6, RCSP-7, or RCSP-8 was prepared.
The appearance and turbidity of the methanol-dispersed sol containing the metal oxide fine particles thus obtained were as shown in Table 5.

[Preparation Example 1]
Preparation of coating liquid for optical substrate (coating liquid for forming hard coat layer film ) 114 g of γ-glycidoxypropyltrimethoxysilane (Z-6040 manufactured by Toray Dow Corning Co., Ltd.), γ-glycidoxypropylmethyldi Prepare a plurality of containers containing a mixed liquid of 29 g of ethoxysilane (Z-6042 manufactured by Toray Dow Corning Co., Ltd.) and 71 g of methanol (Mayashi Junyaku Co., Ltd., methyl alcohol concentration: 99.9 wt%), While stirring, 36 g of 0.01N hydrochloric acid aqueous solution was dropped into these mixed solutions. Furthermore, this liquid mixture was stirred at room temperature all day and night to hydrolyze the silane compound.
Next, in a container containing these hydrolyzed solutions, among the methanol-dispersed sol prepared in Example 16 (solid content concentration: 20% by weight), the metal oxide fine particles CSP- having a refractive index of less than 2.20. 1, CSP-2, CSP-4, CSP-5, CSP-6 or CSP-7, 490 g, metal oxide fine particles CSP-3 or CSP having a refractive index of 2.20 or more, respectively. For each methanol-dispersed sol containing -8, 450 g, 71 g of pure water, 3 g of Tris (2.4-pentanedionato) aluminum III (manufactured by Tokyo Chemical Industry Co., Ltd.) and a silicone surfactant as a leveling agent (Toray Dow Corning Co., Ltd., L-7001) 0.7 g was added and stirred at room temperature all day and night to form a hard coating as a coating composition for optical substrates. Layer film forming coating composition HX-1 (1), HX-2 (1), HX-3 (1), HX-4 (1), HX-5 (1), HX-6 (1), HX-7 (1) and HX-8 (1) were prepared. These coating compositions contain metal oxide fine particles of CSP-1, CSP-2, CSP-3, CSP-4, CSP-5, CSP-6, CSP-7, and CSP-8, respectively. .

[Preparation Example 2]
Preparation of coating liquid for optical substrate (coating liquid for forming hard coat layer film ) 114 g of γ-glycidoxypropyltrimethoxysilane (Z-6040 manufactured by Toray Dow Corning Co., Ltd.), γ-glycidoxypropylmethyldi Prepare a plurality of containers containing a mixed liquid of 29 g of ethoxysilane (Z-6042 manufactured by Toray Dow Corning Co., Ltd.) and 71 g of methanol (Mayashi Junyaku Co., Ltd., methyl alcohol concentration: 99.9 wt%), While stirring, 36 g of 0.01N hydrochloric acid aqueous solution was dropped into these mixed solutions. Furthermore, this liquid mixture was stirred at room temperature all day and night to hydrolyze the silane compound.
Next, among the methanol dispersion sol prepared in Comparative Example 17 (solid content concentration: 20% by weight) in a container containing these hydrolysis solutions, metal oxide fine particles RCSP- having a refractive index of less than 2.20. 1, each methanol dispersion sol containing RCSP-2, RCSP-4, RCSP-5 or RCSP-6 is 490 g, metal oxide fine particles RCSP-3, RCSP-7 or RCSP having a refractive index of 2.20 or more, respectively. For each methanol-dispersed sol containing -8, 450 g, 71 g of pure water, 3 g of Tris (2.4-pentanedionato) aluminum III (manufactured by Tokyo Chemical Industry Co., Ltd.) and a silicone surfactant as a leveling agent (Toray Dow Corning Co., Ltd., L-7001) 0.7 g was added and stirred at room temperature for a whole day and night. HY-1 (1), HY-2 (1), HY-3 (1), HY-4 (1), HY-5 (1), HY-6 (1), HY-7 (1), and HY-8 (1) were prepared. These coating compositions contain RCSP-1, RCSP-2, RCSP-3, RCSP-4, RCSP-5, RCSP-6, RCSP-7, and RCSP-8, respectively, in order. .

[Preparation Example 3]
Preparation of coating liquid for optical substrate (coating liquid for forming hard coat layer film ) 135 g of γ-glycidoxypropyltrimethoxysilane (manufactured by Toray Dow Corning Co., Ltd., Z-6040) and methanol (Hayashi Junyaku Co., Ltd.) ), Methyl alcohol concentration: 99.9% by weight) A plurality of containers containing 50 g of a mixed solution were prepared, and 35 g of a 0.01N hydrochloric acid aqueous solution was dropped into these mixed solutions while stirring. Furthermore, these mixed liquids were stirred at room temperature for a whole day and night to hydrolyze the silane compound.
Next, in a container containing these hydrolyzed solutions, among the methanol-dispersed sol prepared in Example 16 (solid content concentration: 20% by weight), the metal oxide fine particles CSP- having a refractive index of less than 2.20. 1, CSP-2, CSP-4, CSP-5, CSP-6 or CSP-7, each methanol dispersion sol is 600 g, metal oxide fine particles CSP-3 or CSP having a refractive index of 2.20 or more, respectively. For each methanol-dispersed sol containing -8, 550 g, 4 g of Tris (2.4-pentanedionato) iron III (manufactured by Tokyo Chemical Industry Co., Ltd.), glycerol polyglycidyl ether (manufactured by Nagase Chemical Industry Co., Ltd.) , Denacol EX-314, epoxy equivalent 145) 8 g and a silicone surfactant as a leveling agent (manufactured by Dow Corning Toray, L -7001) Add 0.5 g, stir at room temperature all day and night, and form hard coat layer film-forming coating composition HX-1 (2), HX-2 (2), HX as a coating composition for optical substrates -3 (2), HX-4 (2), HX-5 (2), HX-6 (2), HX-7 (2), and HX-8 (2) were prepared. These coating compositions contain metal oxide fine particles of CSP-1, CSP-2, CSP-3, CSP-4, CSP-5, CSP-6, CSP-7, and CSP-8, respectively. .

[Preparation Example 4]
Preparation of coating liquid for optical substrate (coating liquid for forming hard coat layer film ) 135 g of γ-glycidoxypropyltrimethoxysilane (manufactured by Toray Dow Corning Co., Ltd., Z-6040) and methanol (Hayashi Junyaku Co., Ltd.) ), Methyl alcohol concentration: 99.9% by weight) A plurality of containers containing 50 g of a mixed solution were prepared, and 25 g of a 0.01 N hydrochloric acid aqueous solution was dropped into these mixed solutions while stirring. Furthermore, these mixed liquids were stirred at room temperature for a whole day and night to hydrolyze the silane compound.
Next, among the methanol dispersion sol prepared in Comparative Example 17 (solid content concentration: 20% by weight) in a container containing these hydrolysis solutions, metal oxide fine particles RCSP- having a refractive index of less than 2.20. 1, each methanol dispersion sol containing RCSP-2, RCSP-4, RCSP-5 and RCSP-6 is 600 g, metal oxide fine particles RCSP-3, RCSP-7 or RCSP having a refractive index of 2.20 or more. For each methanol-dispersed sol containing -8, 550 g, 4 g of Tris (2.4-pentanedionato) iron III (manufactured by Tokyo Chemical Industry Co., Ltd.), glycerol polyglycidyl ether (manufactured by Nagase Chemical Industry Co., Ltd.) , Denacol EX-314, Epoxy equivalent 145) 8g, and silicone surfactant as leveling agent (Toray Dowconi Ng Co., Ltd., L-7001) 0.5 g was added and stirred at room temperature all day and night to form a hard coat layer film-forming coating composition HY-1 (2), HY as a coating composition for an optical substrate. -2 (2), HY-3 (2), HY-4 (2), HY-5 (2), HY-6 (2) HY-7 (2), HY-8 (2) did. These coating compositions contain RCSP-1, RCSP-2, RCSP-3, RCSP-4, RCSP-5, RCSP-6, RCSP-7, and RCSP-8, respectively, in order. .

[Preparation Example 5]
Preparation of coating liquid for optical substrate (coating liquid for primer layer film formation) Polyurethane emulsion “Superflex 150” (Daiichi Kogyo Seiyaku Co., Ltd., water dispersion type urethane elastomer solid content 30%) which is a commercially available thermoplastic resin A plurality of containers containing 170 g were prepared, and among these, the metal oxide fine particles CSP-1 having a refractive index of less than 2.20 among the methanol-dispersed sol prepared in Example 16 (solid content concentration: 20 wt%). , CSP-2, CCSP-4, CSP-5, CSP-6, or CSP-7, each of the methanol dispersion sol is 395 g, and the metal oxide fine particles CSP-3 or CSP- having a refractive index of 2.20 or more. For each methanol-dispersed sol containing 8, 410 g and 110 g of pure water were added and stirred for 1 hour.
Next, 500 g of methanol (Hayashi Junyaku Co., Ltd., methyl alcohol concentration: 99.9% by weight) is added to these mixed solutions, and a silicone surfactant (manufactured by Toray Dow Corning Co., Ltd., L) as a leveling agent. -7604) 0.3 g was added and stirred at room temperature for a whole day and night to form a primer layer film-forming coating composition PX-1, PX-2, PX-3, PX-4 as a coating composition for an optical substrate. PX-5, PX-6, PX-7, and PX-8 were prepared. These coating compositions contain metal oxide fine particles of CSP-1, CSP-2, CSP-3, CSP-4, CSP-5, CSP-6, CSP-7, and CSP-8, respectively. .

[Preparation Example 6]
Preparation of coating liquid for optical substrate (coating liquid for primer layer film formation) Polyurethane emulsion “Superflex 150” (Daiichi Kogyo Seiyaku Co., Ltd., water dispersion type urethane elastomer solid content 30%) which is a commercially available thermoplastic resin A plurality of containers containing 170 g were prepared, and among these, the metal oxide fine particles RCSP-1 having a refractive index of less than 2.20 among the methanol-dispersed sol (solid content concentration: 20 wt%) prepared in Comparative Example 17 was prepared. Each of the methanol dispersion sols containing RCSP-2, RCSP-4, RCSP-5 or RCSP-6 is 430 g and metal oxide fine particles RCSP-3, RCSP-7 or RCSP-8 having a refractive index of 2.20 or more. Each methanol-dispersed sol containing 395 g and 110 g of pure water was added and stirred for 1 hour.
Next, 500 g of methanol (Hayashi Junyaku Co., Ltd., methyl alcohol concentration: 99.9% by weight) is added to these mixed solutions, and a silicone surfactant (manufactured by Toray Dow Corning Co., Ltd., L) as a leveling agent. -7604) Add 0.3 g, stir at room temperature for a whole day and night, primer layer film forming coating composition PY-1, PY-2, PY-3, PY-4 as a coating composition for an optical substrate, PY-5, PY-6, PY-7, and PY-8 were prepared respectively. These coating compositions contain RCSP-1, RCSP-2, RCSP-3, RCSP-4, RCSP-5, RCSP-6, RCSP-7, and RCSP-8, respectively, in order. .

[Preparation Example 7]
Preparation of plastic lens substrate for testing (1)
(1) Pretreatment of plastic lens substrate Commercially available plastic lens substrate “monomer name: MR-174” (manufactured by Mitsui Chemicals, Inc., refractive index of substrate 1.74) and “monomer name: MR-7” (Mitsui Chemicals Co., Ltd., the refractive index of the base material 1.67) was prepared for the following tests and evaluations.
Subsequently, these plastic lens base materials were immersed in a 10 wt% KOH aqueous solution kept at 40 ° C. for 2 minutes for etching treatment. Further, these were taken out, washed with water, and then sufficiently dried.

(2) Formation of hard coat layer film The coating composition (hard coat paint) for forming the hard coat layer film obtained in Preparation Examples 1 and 2 was applied to the surface of the plastic lens substrate, respectively. Formed. In addition, application | coating of this coating composition was performed using the dipping method (drawing speed 250mm / min).
Next, after drying the said coating film for 10 minutes at 90 degreeC, it heat-processed for 2 hours at 110 degreeC, and hardened | cured the coating film (hard-coat layer).
In addition, the film thickness after hardening of the said hard-coat layer film | membrane formed in this way was about 2.0-2.6 micrometers.

(3) Formation of antireflection film layer An inorganic oxide component having the following constitution was deposited on the surface of the hard coat layer film by a vacuum deposition method. Here, the order of SiO ₂ : 0.06λ, ZrO ₂ : 0.15λ, SiO ₂ : 0.04λ, ZrO ₂ : 0.25λ, and SiO ₂ : 0.25λ from the hard coat layer side toward the atmosphere side. Each of the layers of the antireflection layer film laminated in (1) was formed. The design wavelength λ was 520 nm.

[Preparation Example 8]
Preparation of plastic lens substrate for testing (2)
(1) Pretreatment of plastic lens substrate Under the same conditions as in Preparation Example 7, the plastic substrate was pretreated.
(2) Formation of primer layer film The surface of the plastic lens substrate was coated with the primer layer film-forming paint composition (primer paint) obtained in Preparation Examples 5 and 6 to form a coating film. . In addition, application | coating of this coating composition was performed using the dipping method (pickup speed 120mm / min).
Next, the said coating film was heat-processed at 100 degreeC for 10 minute (s), and the coating film (primer layer) was pre-hardened.
In addition, the film thickness after preliminary curing of the primer layer formed in this manner was approximately 0.5 to 0.7 μm.

(3) Formation of Hard Coat Layer Film A coating composition for forming a hard coat layer film obtained in Preparation Examples 3 and 4 (hard coat paint) is formed on the surface of the plastic lens substrate formed with the primer layer film. ) Was applied respectively. In addition, application | coating of this coating composition was performed using the dipping method (drawing speed 250mm / min).
Next, after drying the said coating film for 10 minutes at 90 degreeC, it heat-processed for 2 hours at 110 degreeC, and hardened | cured the coating film (hard-coat layer). At this time, the main curing of the primer layer was also performed at the same time.
In addition, the film thickness of the hard coat layer thus formed was approximately 2.0 to 2.6 μm.
(4) Formation of Antireflective Film Layer Film Under the same conditions as in Preparation Example 7, an antireflective layer film layer was formed on the surface of the hard coat layer.

[Evaluation Test 1]
Coating composition HX-1 (1), HX-2 (1), HX-3 (1), HX-4 (1), HX-5 (1) for forming a hard coat layer film obtained in Preparation Example 1 ), HX-6 (1), HX-7 (1) and HX-8 (1), respectively, a hard coat layer and an antireflection film layer are formed on the plastic lens substrate by the method shown in Preparation Example 7. did. Here, the plastic lens substrate “monomer name: MR-7” was used.
For the substrates HX-1, HX-2, HX-3, HX-4, HX-5, HX-6, HX-7 and HX-8 obtained in this way, using the above evaluation test method, Appearance (interference fringes), appearance (cloudiness), scratch resistance, adhesion, weather resistance and light resistance were tested and evaluated. The results are shown in Table 6.

[Evaluation Test 2]
Coating composition HY-1 (1), HY-2 (1), HY-3 (1), HY-4 (1), HY-5 (1) for forming the hard coat layer film obtained in Preparation Example 2 ), HY-6 (1), HY-7 (1) and HY-8 (1), a hard coat layer and an antireflection film layer are formed on the plastic lens substrate by the method shown in Preparation Example 7, respectively. did. Here, the plastic lens substrate “monomer name: MR-7” was used.
With respect to the substrates HY-1, HY-2, HY-3, HY-4, HY-5, HY-6, HY-7, and HY-8 thus obtained, the above evaluation test method was used. Appearance (interference fringes), appearance (cloudiness), scratch resistance, adhesion, weather resistance and light resistance were tested and evaluated. The results are shown in Table 7.

[Evaluation Test 3]
Coating composition PX-1, PX-2, PX-3, PX-4, PX-5, PX-6, PX-7 and PX-8 for primer layer film formation obtained in Preparation Example 5, and preparation Using the coating composition for hard coat layer film formation shown in Table 8 obtained in Example 3, a primer layer, a hard coat layer, and an antireflection film layer were formed on the plastic lens substrate by the method shown in Preparation Example 8, respectively. did.
Here, the plastic lens substrate “monomer name: MR-174” was used.
For the substrates PX-1, PX-2, PX-3, PX-4, PX-5, PX-6, PX-7 and PX-8 obtained in this way, using the above evaluation test method, Appearance (interference fringes), appearance (cloudiness), scratch resistance, adhesion, weather resistance and light resistance were tested and evaluated. The results are shown in Table 8. In addition, about light resistance, since there was discoloration of the board | substrate itself used for the test, the test was canceled.

[Evaluation Test 4]
Coating composition PY-1, PY-2, PY-3, PY-4, PY-5, PY-6, PY-7 and PY-8 for primer layer film formation obtained in Preparation Example 6, and preparation Using the coating composition for hard coat layer film formation shown in Table 9 obtained in Example 4, a primer layer, a hard coat layer, and an antireflection film layer were formed on the plastic lens substrate by the method shown in Preparation Example 8, respectively. did. Here, the plastic lens substrate “monomer name: MR-174” was used.
For the substrates PY-1, PY-2, PY-3, PY-4, PY-5, PY-6, PY-7, and PY-8 obtained in this way, using the above evaluation test method, Appearance (interference fringes), appearance (cloudiness), scratch resistance, adhesion, weather resistance and light resistance were tested and evaluated. The results are shown in Table 9. In addition, about light resistance, since there was discoloration of the board | substrate itself used for the test, the test was canceled.

Claims (24)

An aqueous dispersion sol containing metal oxide fine particles obtained by coating the surface of titanium oxide fine particles having an average particle diameter of 15 to 60 nm measured by a dynamic light scattering method with at least a silica-based oxide or a silica-based composite oxide. There,
(1) The titanium oxide-based fine particles satisfy the following requirements (i) and (ii), and have a rutile crystal structure: a composite oxide or titanium containing titanium and tin; and tin and silicon And a composite oxide crystalline fine particle having an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm and a specific surface area of 70 to 155 m ² / g, and a refractive index of 2.2 to In the range of 2.7,
(2) The coating layer has a refractive index lower by 0.2 or more than the refractive index of the titanium oxide fine particles, and the refractive index of the metal oxide fine particles provided with the coating layer is 2.0-2. And (3) the water-dispersed sol contains 1 to 30% by weight of the metal oxide fine particles, and the turbidity is in the range of 0.1 to 10 cm ^−1. An aqueous dispersion sol of metal oxide fine particles.
Requirement (i): The interplanar spacing d ¹ of the (310) crystal plane determined from X-ray diffraction of the titanium oxide-based fine particles is in the range of 0.1440 to 0.1460 nm, and (301) the interplanar spacing of the crystal plane. d ² is in the range of 0.1355~0.1370nm.
Requirements (ii): wherein as determined by X-ray diffraction of the titanium oxide-based fine particles, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ² ) is in the range of 9/100 to 20/100. The titanium oxide-based fine particles are obtained by firing and pulverizing composite oxide particles containing titanium and tin or composite oxide particles containing titanium, tin , and silicon. An aqueous dispersion sol of the metal oxide fine particles described.   The water-dispersed sol of metal oxide fine particles according to claim 1, wherein the silica-based oxide is silicon dioxide.   The metal according to claim 1, wherein the silica-based composite oxide is a silica-based composite oxide containing silicon and at least one metal element selected from zirconium, antimony, tin, and aluminum. Water dispersion sol of fine oxide particles.   2. The particle frequency distribution when the titanium oxide fine particles are measured by a dynamic light scattering method, wherein the distribution frequency of titanium oxide fine particles having a particle diameter of 100 nm or more is 1% or less. A water-dispersed sol of metal oxide fine particles according to any one of -4. The composite oxide particles are mixed aqueous solution containing titanic acid peroxide and potassium stannate or mixed aqueous solution containing titanic acid peroxide, potassium stannate , and silicon compound in an autoclave and heated to 150 to 250 ° C. It is hydrothermally treated at a temperature to produce a composite oxide containing titanium and tin or a composite oxide containing titanium, tin and silicon, and then drying and granulating the composite oxide. The water-dispersed sol of metal oxide fine particles according to claim 2.   The water-dispersed sol of metal oxide fine particles according to claim 6, wherein the silicon compound is at least one selected from silica fine particles, silicic acid, and silicon alkoxide.   The composite oxide particles are obtained by simultaneously drying and granulating the composite oxide by subjecting the mixed aqueous solution containing the composite oxide to spray drying using a spray dryer. An aqueous dispersion sol of metal oxide fine particles according to 6 or 7.   The titanium oxide-based fine particles are obtained by firing the composite oxide particles at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain composite oxide particles having an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm. The water-dispersed sol of metal oxide fine particles according to any one of claims 2 to 8, which is produced and then pulverized by using a pulverizer.   The titanium oxide-based fine particles are dispersed in pure water or ultrapure water by pulverizing the composite oxide particles in a pulverizer, and then the aqueous dispersion is used in a wet classifier. 10. The water-dispersed sol of fine metal oxide particles according to claim 9, wherein at least coarse particles having a particle diameter of 100 nm or more as measured by a scattering method are separated and removed.   The metal oxide fine particles are mixed with at least one silicon compound selected from silicon alkoxide and silicic acid in an aqueous dispersion containing the titanium oxide fine particles, and then the silicon compound is hydrolyzed to produce the titanium oxide. The water-dispersed sol of metal oxide fine particles according to any one of claims 1 to 3 and 5 to 10, wherein the surface of the fine particles is coated with a silica-based oxide.   In the aqueous dispersion in which the metal oxide fine particles include the titanium oxide fine particles, at least one silicon compound selected from silicon alkoxide and silicic acid, zirconate peroxide, antimonate, stannate and At least one metal compound selected from aluminates is mixed, and then the silicon compound and the metal compound are hydrolyzed to coat the surface of the titanium oxide fine particles with a silica-based composite oxide. The water-dispersed sol of metal oxide fine particles according to any one of claims 1, 2, and 4 to 10.   13. The water-dispersed sol of fine metal oxide particles according to claim 7, 11 or 12, wherein the silicon alkoxide is tetramethoxysilane or a condensate thereof, or tetraethoxysilane or a condensate thereof.   When the metal oxide fine particles represent the weight of the titanium oxide-based fine particles as C and the weight of the coating layer as S, the weight ratio (S / C) is 1/100 to 1 in terms of oxide. The surface of the titanium oxide-based fine particles is coated with the silica-based oxide or the silica-based composite oxide so as to be in a range of 50/100. An aqueous dispersion sol of the metal oxide fine particles described. Metal oxide formed by coating the surface of titanium oxide fine particles having an average particle diameter of 15 to 60 nm measured by a dynamic light scattering method and satisfying the following requirements (i) and (ii) with at least a silica-based oxide A method for preparing an aqueous dispersion sol containing fine particles,
(A) A mixed aqueous solution containing titanic acid peroxide and potassium stannate or a mixed aqueous solution containing titanic acid peroxide, potassium stannate, and a silicon compound is placed in an autoclave and hydrothermally treated at a temperature of 150 to 250 ° C. And producing a composite oxide containing titanium and tin or a composite oxide containing titanium, tin and silicon,
(B) The composite oxide produced in the step (a) is dried and granulated, so that composite oxide particles or titanium having an average particle diameter of 1 to 80 μm containing titanium and tin, and tin , Obtaining composite oxide particles having an average particle diameter of 1 to 80 μm containing silicon,
(C ′) The composite oxide particles obtained in the step (b) are baked at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere, and a composite having an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm. Producing oxide particles;
(D ′) a step of subjecting the composite oxide particles produced in the step (c ′) to a pulverizer and pulverization, and dispersing the pulverized one in pure water or ultrapure water to obtain an aqueous dispersion;
(F) The aqueous dispersion obtained in the step (d ′) or the dispersion is subjected to a wet classifier to separate at least coarse particles having a particle diameter of 100 nm or more as measured by a dynamic light scattering method. -By mixing (i) at least one silicon compound selected from silicon alkoxide and silicic acid into the aqueous dispersion obtained through the step (e) to be further removed, and hydrolyzing the silicon compound A method for preparing an aqueous dispersion sol of metal oxide fine particles, comprising a step of obtaining an aqueous dispersion sol containing metal oxide fine particles having the surface of the titanium oxide fine particles coated with a silica-based oxide.
Requirement (i): The interplanar spacing d ¹ of the (310) crystal plane determined from X-ray diffraction of the titanium oxide-based fine particles is in the range of 0.1440 to 0.1460 nm, and (301) the interplanar spacing of the crystal plane. d ² is in the range of 0.1355~0.1370nm.
Requirements (ii): wherein as determined by X-ray diffraction of the titanium oxide-based fine particles, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ² ) is in the range of 9/100 to 20/100. Metal oxide obtained by coating the surface of titanium oxide fine particles having an average particle diameter of 15 to 60 nm measured by a dynamic light scattering method and satisfying the following requirements (i) and (ii) with at least a silica-based composite oxide A method for preparing an aqueous dispersion sol containing fine particles,
(A) A mixed aqueous solution containing titanic acid peroxide and potassium stannate or a mixed aqueous solution containing titanic acid peroxide, potassium stannate, and a silicon compound is placed in an autoclave and hydrothermally treated at a temperature of 150 to 250 ° C. And producing a composite oxide containing titanium and tin or a composite oxide containing titanium, tin and silicon,
(B) The composite oxide produced in the step (a) is dried and granulated, so that composite oxide particles or titanium having an average particle diameter of 1 to 80 μm containing titanium and tin, and tin , Obtaining composite oxide particles having an average particle diameter of 1 to 80 μm containing silicon,
(C ′) The composite oxide particles obtained in the step (b) are baked at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere, and a composite having an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm. Producing oxide particles;
(D ′) a step of subjecting the composite oxide particles produced in the step (c ′) to a pulverizer and pulverization, and dispersing the pulverized one in pure water or ultrapure water to obtain an aqueous dispersion;
(F) The aqueous dispersion obtained in the step (d ′) or the dispersion is used in a wet classifier,
In the aqueous dispersion obtained further through the step (e) of separating and removing at least coarse particles having a particle diameter of 100 nm or more as measured by a dynamic light scattering method, (i) selected from silicon alkoxide and silicic acid In addition, at least one silicon compound and at least one metal compound selected from zirconate peroxide, antimonate, stannate, and aluminate are mixed to hydrolyze the silicon compound and the metal compound. A method for preparing a water-dispersed sol of metal oxide fine particles, comprising a step of obtaining a water-dispersed sol containing metal oxide fine particles in which the surface of the titanium oxide-based fine particles is coated with a silica-based composite oxide by decomposition. .
Requirement (i): The interplanar spacing d ¹ of the (310) crystal plane determined from X-ray diffraction of the titanium oxide-based fine particles is in the range of 0.1440 to 0.1460 nm, and (301) the interplanar spacing of the crystal plane. d ² is in the range of 0.1355~0.1370nm.
Requirements (ii): wherein as determined by X-ray diffraction of the titanium oxide-based fine particles, (310) crystal face of the peak intensity P ¹ and (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ² ) is in the range of 9/100 to 20/100.   17. The water-dispersed sol of metal oxide fine particles according to claim 15 or 16, wherein the silicon compound used in the step (a) is at least one selected from silica fine particles, silicic acid and silicon alkoxide. Preparation method.   18. The pH of the mixed aqueous solution obtained in the step (a) is adjusted to a range of 3 to 10 before being used in the step (b). Of preparing an aqueous dispersion sol of metal oxide fine particles.   In the step (b), the mixed aqueous solution obtained in the step (a) is spray-dried using a spray dryer to simultaneously dry and granulate the composite oxide contained in the mixed aqueous solution. The method for preparing an aqueous dispersion sol of metal oxide fine particles according to any one of claims 15 to 18.   The silicon compound used in the step (a) and the silicon alkoxide used in the step (f) are tetramethoxysilane or a condensate thereof, or tetraethoxysilane or a condensate thereof. A method for preparing an aqueous dispersion sol of metal oxide fine particles according to any one of 15 to 19.   By adding an anion exchange resin and / or a cation exchange resin to the water dispersion sol obtained in the step (f) and stirring, the ionized substance contained in the water dispersion sol is removed. The method for preparing an aqueous dispersion sol of metal oxide fine particles according to any one of claims 15 to 20.   An organic solvent-dispersed sol of metal oxide fine particles obtained by dispersing metal oxide fine particles contained in the water-dispersed sol of metal oxide fine particles according to claim 1 in an organic solvent.   The organic solvent-dispersed sol of metal oxide fine particles according to claim 22, wherein the organic solvent is at least one organic compound selected from alcohols, ethers and ketones.   The organic solvent-dispersed sol is obtained by subjecting the water-dispersed sol of metal oxide fine particles according to any one of claims 1 to 14 to a solvent displacement device, and replacing water contained in the water-dispersed sol with an organic solvent. 24. The organic solvent-dispersed sol of metal oxide fine particles according to claim 22 or 23.

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