JP2011136850A - Method for preparing organic solvent-dispersed sol including high refractive index metal oxide fine particle, such organic solvent-dispersed sol, and coating composition obtained using the organic solvent-dispersed sol - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preparing an organic solvent-dispersed sol including metal oxide fine particles having a high refractive index and low photocatalytic activity, such an organic solvent-dispersed sol, and a coating composition obtained using the organic solvent-dispersed sol. <P>SOLUTION: The method for preparing an organic solvent-dispersed sol including metal oxide fine particles includes drying and firing an aggregate of surface-coated titanium-based fine particles obtained by coating surfaces of titanium-based fine particles comprising a compound oxide containing titanium and tin and/or silicon with a silica-based oxide or a silica-based compound oxide, and pulverizing the resulting sintered body of the aggregate in the presence of an organic solvent. Such an organic solvent-dispersed sol and the coating composition obtained using the organic solvent-dispersed sol are also provided. The metal oxide fine particles have not only a high refractive index but also low photocatalytic activity. <P>COPYRIGHT: (C)2011,JPO&INPIT

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. The present invention relates to a method for preparing an organic solvent-dispersed sol containing, an organic solvent-dispersed sol obtained from the method, and a coating composition obtained using the organic solvent-dispersed sol.

  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 comprising a 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.

Under such circumstances, the present inventors performed a special processing treatment in order to solve the above problems and obtain a curable coating film having both high refractive index and weather resistance and light resistance. Water-dispersed sol of metal oxide fine particles obtained by coating silica-based oxide or silica-based composite oxide on the surface of titanium-based fine particles having a rutile-type crystal structure, a method for preparing the same, and using the water-dispersed sol as a solvent substitution step An organic solvent-dispersed sol obtained and a coating composition obtained by using the organic solvent-dispersed sol have been developed and applications have been filed. (Refer to published patent publications such as Japanese Patent Application No. 2009-187055 and International Patent Application PCT / JP2009 / 64221.)
However, the organic solvent-dispersed sol has to be prepared by preparing a water-dispersed sol of metal oxide fine particles and then substituting the water contained in the water-dispersed sol with a desired organic solvent.

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

As described above, the present inventors have earnestly studied whether or not there is no method for directly preparing the organic solvent dispersed sol without preparing the organic solvent dispersed sol through the water dispersed sol of metal oxide fine particles. As a result of the overlapping, the surface of the titanium-based fine particles having a rutile crystal structure is coated with silica-based oxide or silica-based composite oxide, and then dried and fired. It was found that the product may be pulverized in the presence of an organic solvent, and the pulverized metal oxide fine particles (surface-coated titanium-based fine particles) may be dispersed in the organic solvent, thereby completing the present invention. That is, the present invention provides a surface-coated titanium system in which the surface of titanium-based fine particles (primary particles) composed of composite oxide particles containing titanium and tin and / or silicon are coated with silica-based oxide or silica-based composite oxide. After the fine particles (secondary particles) are dried and granulated, a surface-coated titanium-based fine particle aggregate (tertiary particles) is produced, and then the surface-coated titanium-based fine particle aggregate is fired, and the fired product is then present in the presence of an organic solvent. A method for preparing an organic solvent-dispersed sol in which metal oxide fine particles (quaternary particles) are further pulverized and further dispersed in an organic solvent, and an organic solvent-dispersed sol obtained from the method are provided. The purpose is that.
Furthermore, an object of the present invention is to provide a coating composition obtained using the organic solvent-dispersed sol.

The method for preparing an organic solvent-dispersed sol of high refractive index metal oxide fine particles according to the present invention is as follows:
A method for preparing an organic solvent-dispersed sol containing high-refractive-index metal oxide fine particles obtained by coating the surface of titanium-based fine particles containing titanium and tin and / or silicon with at least a silica-based oxide,
(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. A step of generating titanium-based fine particles (primary particles) made of a complex oxide;
(B) By mixing at least one silicon compound selected from silicon alkoxide and silicic acid into the mixed aqueous solution containing the titanium-based fine particles obtained in the step (a), and hydrolyzing the silicon compound. Obtaining surface-coated titanium-based fine particles (secondary particles) obtained by coating the surface of the titanium-based fine particles with a silica-based oxide;
(C) a step of obtaining a surface-coated titanium-based fine particle aggregate (tertiary particles) having an average particle diameter of 1 to 80 μm by drying and granulating the surface-coated titanium-based fine particles obtained in the step (b),
(D) A step of baking the surface-coated titanium-based particle aggregate obtained in the step (c) at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain a fired product of the surface-coated titanium-based particle aggregate. ,
(E) The fired product of the surface-coated titanium-based particle aggregate obtained in the step (d) is pulverized in the presence of an organic solvent, and the average particle size when measured by a dynamic light scattering method is 8 to 60 nm. A step of obtaining an organic solvent-dispersed sol obtained by further dispersing the metal oxide fine particles (quaternary particles) in an organic solvent, and (f) the organic solvent dispersion obtained in the step (e). The method is characterized in that it includes a step 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 by subjecting the liquid to a wet classifier as necessary.

Furthermore, the method for preparing the organic solvent-dispersed sol of the high refractive index metal oxide fine particles according to the present invention,
A method for preparing an organic solvent-dispersed sol containing high refractive index metal oxide fine particles obtained by coating at least the surface of a composite oxide particle containing titanium and tin and / or silicon with a silica-based composite oxide,
(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. A step of generating titanium-based fine particles (primary particles) made of a complex oxide;
(B) In the mixed aqueous solution containing the titanium-based fine particles obtained in the step (a), at least one silicon compound selected from silicon alkoxide and silicic acid, zirconate peroxide, antimonate, and stannic acid A surface of the titanium-based fine particles is coated with a silica-based composite oxide by mixing at least one metal compound selected from a salt and an aluminate and hydrolyzing the silicon compound and the metal compound. A step of obtaining surface-coated titanium-based fine particles (secondary particles),
(C) a step of obtaining a surface-coated titanium-based fine particle aggregate (tertiary particles) having an average particle diameter of 1 to 80 μm by drying and granulating the surface-coated titanium-based fine particles obtained in the step (b),
(D) A step of baking the surface-coated titanium-based particle aggregate obtained in the step (c) at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain a fired product of the surface-coated titanium-based particle aggregate. ,
(E) The fired product of the surface-coated titanium-based particle aggregate obtained in the step (d) is pulverized in the presence of an organic solvent, and the average particle size when measured by a dynamic light scattering method is 8 to 60 nm. A step of obtaining an organic solvent-dispersed sol obtained by further dispersing the metal oxide fine particles (quaternary particles) in an organic solvent, and (f) the organic solvent dispersion obtained in the step (e). The method is characterized in that it includes a step 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 by subjecting the liquid to a wet classifier as necessary.

The silicon compound used in the step (a) is preferably at least one selected from silica fine particles, silicic acid and silicon alkoxide.
The silicon alkoxide used in the step (b) is preferably tetramethoxysilane or a condensate thereof, or tetraethoxysilane or a condensate thereof.
Furthermore, the surface-coated titanium-based fine particles obtained in the step (b) have a weight ratio (S / C) when the weight of the titanium-based fine particles is represented by C and the weight of the coating layer is represented by S. 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 1/100 to 50/100 in terms of oxide.

The surface-coated titanium-based particle aggregate obtained in the step (c) is dried and granulated by subjecting the mixed aqueous solution containing the surface-coated titanium-based fine particles to a spray dryer and spray-drying. Are preferably performed simultaneously.
The organic solvent used in the step (e) is an alcohol such as methanol, ethanol, butanol, propanol, isopropyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl. It is preferably at least one organic compound selected from ethers such as ether and ketones such as methyl ethyl ketone and γ-butyrolactone.
Furthermore, it is preferable that the organic solvent used in the step (e) contains a carboxylic acid compound and / or an amine compound. Here, the carboxylic acid-based compound is preferably at least one selected from tartaric acid, citric acid, and malic acid. The amine compound is preferably at least one selected from diisopropylamine, diisobutylamine and tetramethylammonium hydroxide.
Further, by adding an anion exchange resin and / or a cation exchange resin to the organic solvent dispersion sol obtained in the step (f) and stirring, the ionized substance contained in the organic solvent dispersion sol is obtained. It is preferable to remove it.

The organic solvent dispersion sol of the high refractive index metal oxide fine particles according to the present invention is:
An organic solvent-dispersed sol of metal oxide fine particles having a high refractive index obtained from the preparation method according to any one of the above,
(1) The titanium-based fine particles constituting the metal oxide fine particles are crystalline particles having a rutile crystal structure, have an X-ray diffraction crystallite diameter of 3 to 13 nm, and have a refractive index of 2 In the range of 2 to 2.7,
(2) The coating layer constituting the metal oxide fine particles has a refractive index lower by 0.2 or more than the refractive index of the titanium-based fine particles, and (3) the metal oxide fine particles have an average of 8 to 60 nm. It has a particle diameter and a specific surface area of 70 to 200 m ² / g, and its refractive index is in the range of 2.0 to 2.5. (4) The organic solvent-dispersed sol is 5 to 40% by weight. The metal oxide fine particles are included, and the turbidity is in the range of 0.1 to 11.0 cm ⁻¹ .

The titanium-based fine particles have a (310) crystal plane spacing d ¹ in the range of 0.1440 to 0.1460 nm and (301) a crystal plane spacing d ² of 0. It is preferable to be in the range of 1355 to 0.1370 nm.
Further, the titanium-based fine particles, as determined by X-ray diffraction, (310) and the peak intensity P ¹ of the crystal plane (110) relative peak intensity ratio of the peak intensity P ² of the crystal plane (P ¹ / P ²⁾ is It is preferably in the range of 9/100 to 20/100.

The coating layer is preferably a silica-based oxide substantially made of silicon dioxide.
The coating layer is preferably a silica-based composite oxide containing silicon and at least one metal element selected from zirconium, antimony, tin, and aluminum.
Further, the metal oxide fine particles may have a distribution frequency of relatively coarse titanium-based fine particles having a particle size of 100 nm or more in a particle size frequency distribution measured by a dynamic light scattering method of 1% or less. preferable.

  In addition, the organic solvent includes 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, It is preferably at least one organic compound selected from ketones such as γ-butyrolactone.

The coating composition according to the present invention is characterized by comprising high refractive index metal oxide fine particles and a binder component contained in any of the above organic solvent dispersion sols.
The binder component is preferably an organosilicon compound.
Furthermore, the organosilicon compound is preferably an organosilicon compound represented by the following general formula (I) and / or a hydrolyzate thereof.
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.)
The organosilicon compound has a weight ratio (X / Y) where X represents the weight of the organosilicon compound converted to SiO ₂ , and Y represents the weight of the high refractive index metal oxide fine particles. Is preferably included at a ratio of 30/70 to 90/10.

The binder component is preferably a thermosetting organic resin or a thermoplastic organic resin.
The thermosetting organic resin is preferably at least one selected from a urethane resin, an epoxy resin, and a melamine resin.
Furthermore, the thermoplastic organic resin is preferably at least one selected from an acrylic resin, a urethane resin, and an ester resin.
The thermosetting organic resin or thermoplastic organic resin has a weight ratio (A / B) when the weight of the resin compound is represented by A and the weight of the high refractive index metal oxide fine particles is represented by B. Is preferably included at a ratio of 90/10 to 30/70.

The coating composition is preferably a coating composition for optical substrates.
Moreover, it is preferable that the said coating composition for optical base materials is a coating composition for hard-coat layer film formation.
Furthermore, the coating composition for an optical substrate is preferably a coating composition for forming a primer layer film.

According to the preparation method of the present invention, after preparing a water-dispersed sol of high-refractive-index metal oxide fine particles, the water-dispersed sol is directly subjected to a high refractive index without being subjected to a solvent replacement step or the like to obtain an organic solvent-dispersed sol. It is extremely economical because an organic solvent-dispersed sol of fine metal oxide particles can be prepared.
The high refractive index metal oxide fine particles contained in the organic solvent-dispersed sol obtained from the method of the present invention itself have a high refractive index of 2.0 to 2.5, and the photocatalytic activity thereof is considerably low. For example, the curable coating film formed using the coating solution containing the fine particles and the plastic substrate are not very likely to be deteriorated. The possibility of causing inning) is very low. This is because the titanium-based fine particles constituting the metal oxide fine particles are crystalline fine particles having a special physical property. That is, the titanium-based fine particles have a rutile-type crystal structure having a crystallite diameter in a range of 3 to 13 nm as measured by an X-ray diffraction method, and itself has a high refraction of 2.2 to 2.7. Have a rate.

  More specifically, since the titanium-based fine particles constituting the high refractive index metal oxide fine particles are fired at a relatively high temperature, that is, a temperature of 300 to 800 ° C., the crystallinity thereof (in the present invention, X-ray diffraction crystallite diameter) is increased, and as a result, the refractive index of the fine particles can be increased. However, since the titanium-based fine particles are coated with a silica-based oxide or a silica-based composite oxide and then baked, the specific surface area of the titanium-based fine particles cannot be directly measured, but the crystallinity increases. Accordingly, it is expected that the specific surface area of the fine particles themselves decreases. Furthermore, the titanium-based fine particles are not only coated with the above components, but also baked at a relatively high temperature, so that the number of OH groups present on the surface of the fine particles is extremely small. is expected. This reduces the number of OH groups (for example, .OH) that are converted into free radicals when the fine particles are exposed to ultraviolet rays. As a result, the photocatalytic activity can be weakened.

The high-refractive-index metal oxide fine particles are formed by surface-coated titanium-based fine particle aggregates (that is, aggregates of titanium-based fine particles surface-coated with silica-based oxide or silica-based composite oxide) in the presence of an organic solvent. Therefore, the light reflectance on the particle surface is small, and as a result, there is little possibility of causing light scattering on the particle surface. Furthermore, since the surface-coated titanium-based fine particle aggregate is an aggregate of surface-coated titanium-based fine particles, it can be easily pulverized into each titanium-based fine particle. An organic solvent-dispersed sol containing such high-refractive-index metal oxide fine particles has little turbidity and is almost transparent or close thereto.
The organic solvent-dispersed sol according to the present invention thus obtained contains high refractive index metal oxide fine particles having the following physical characteristics and has a turbidity of 0.1 to 11.0 cm ^−1. (However, when the content of the fine particles is 5 to 40% by weight).
(1) The titanium-based fine particles constituting the metal oxide fine particles are crystal particles having a rutile crystal structure, have an X-ray diffraction crystallite diameter of 3 to 13 nm, and have a refractive index of 2. It is in the range of 2 to 2.7.
(2) The coating layer constituting the metal oxide fine particles has a refractive index lower by 0.2 or more than the refractive index of the titanium-based fine particles.
(3) The metal oxide fine particles have an average particle diameter of 8 to 60 nm and a specific surface area of 70 to 200 m ² / g, and the refractive index is in the range of 2.0 to 2.5.

A coating composition for an optical substrate (for example, a coating solution for forming a hard coat layer) using the organic solvent dispersion sol containing the high refractive index metal oxide fine particles obtained as described above as a raw material composition is used. For example, it is based on 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. It can be easily formed on a material. 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.
Moreover, since an organic solvent 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 composition for an optical substrate prepared using the organic solvent-dispersed sol according to the present invention has a curability such as a hard coat layer film and a primer layer film on an optical substrate such as a plastic lens substrate. It can be suitably used when forming a coating film.

In addition, the curable coating film obtained using the coating composition which concerns on this invention, for example, the said coating composition for optical base materials, has the characteristics 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. is 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.

Hereinafter, the preparation method of the organic solvent dispersion sol containing the high refractive index metal oxide fine particles according to the present invention and the organic solvent dispersion sol obtained from the method will be specifically described.
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. Say things.

[Preparation method of organic solvent dispersion sol]
Preparation method-1
The first method for preparing an organic solvent-dispersed sol according to the present invention (hereinafter referred to as “Preparation Method-1”) is as follows.
A method for preparing an organic solvent-dispersed sol containing high-refractive-index metal oxide fine particles obtained by coating the surface of titanium-based fine particles containing titanium and tin and / or silicon with at least a silica-based oxide,
(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. A step of generating titanium-based fine particles (primary particles) made of a complex oxide;
(B) By mixing at least one silicon compound selected from silicon alkoxide and silicic acid into the mixed aqueous solution containing the titanium-based fine particles obtained in the step (a), and hydrolyzing the silicon compound. Obtaining surface-coated titanium-based fine particles (secondary particles) obtained by coating the surface of the titanium-based fine particles with a silica-based oxide;
(C) a step of obtaining a surface-coated titanium-based fine particle aggregate (tertiary particles) having an average particle diameter of 1 to 80 μm by drying and granulating the surface-coated titanium-based fine particles obtained in the step (b),
(D) A step of baking the surface-coated titanium-based particle aggregate obtained in the step (c) at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain a fired product of the surface-coated titanium-based particle aggregate. ,
(E) The fired product of the surface-coated titanium-based particle aggregate obtained in the step (d) is pulverized in the presence of an organic solvent, and the average particle size when measured by a dynamic light scattering method is 8 to 60 nm. A step of obtaining an organic solvent-dispersed sol obtained by further dispersing the metal oxide fine particles (quaternary particles) in an organic solvent, and (f) the organic solvent dispersion obtained in the step (e). The liquid is subjected to a wet classifier as necessary, and includes a step 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.
Next, each of these steps will be described as follows.

Step (a)
In the present invention, titanium-based fine particles made of a composite oxide containing titanium and tin and / or silicon are titanium-based fine particles made of a composite oxide containing titanium and tin, and titanium, tin, and silicon. Meaning titanium-based fine particles composed of a titanium-based composite oxide and the like, and a part of these compounds schematically shown by chemical formulas are as follows.

｜ ｜
-O-Ti-O-Sn-O-
｜ ｜

｜ ｜ ｜
-O-Ti-O-Sn-O-Si-O-
｜ ｜ ｜

The titanium-based fine particles are obtained by placing a mixed aqueous solution containing titanic acid peroxide and potassium stannate and / or silicon compound in an autoclave and hydrothermally treating them at a temperature of 150 to 250 ° C., so that titanium, tin and / or It is obtained as titanium-based fine particles (primary particles) made of a complex oxide containing silicon.
More specifically, this process is as follows.
(1) A titanium tetrachloride aqueous solution containing about 7 to 8% by weight of titanium tetrachloride in terms of TiO ₂ and an aqueous ammonia containing about 10 to 20% by weight of ammonia (NH ₃ ) are mixed to obtain a pH of about 9 to Ten white slurry liquids are 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.

(2) Next, a cation exchange resin is mixed with the aqueous solution of titanic acid peroxide, and an aqueous potassium stannate solution containing about 0.5 to 2% by weight of potassium stannate in terms of SnO ₂ is mixed with stirring. Add gradually.
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., the crystallization of the composite oxide containing titanium and tin and / or silicon is difficult to proceed, so the crystallinity of the resulting particles (primary particles) becomes low. When the hydrothermal treatment temperature exceeds 250 ° C., not only the crystallization of the composite oxide proceeds excessively, but also the resulting particles tend to aggregate, so hydrothermal treatment is performed at a temperature appropriately selected from the above range. Is preferred. 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 titanium-based fine particles (primary particles) having a rutile crystal structure and composed of a composite oxide containing titanium, tin, and silicon is obtained. However, when the silica source is not mixed, a mixed aqueous solution containing titanium-based fine particles (primary particles) made of a composite oxide containing titanium and tin is obtained.
Next, the obtained mixed aqueous solution is cooled to room temperature or a temperature close thereto.

Step (b)
In this step, at least one silicon compound selected from silicon alkoxide and silicic acid is mixed with the mixed liquid containing the titanium-based fine particles (primary particles) obtained above to hydrolyze or dehydrate the silicon compound. By surface condensation, surface-coated titanium-based fine particles (secondary particles) obtained by coating the surface of the titanium-based fine particles with a silica-based oxide are obtained.
Here, the silicon alkoxide is preferably tetramethoxysilane or a condensate thereof, or tetraethoxysilane or a condensate thereof. As the condensate of the tetramethoxysilane, a 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 is represented by the general formula Si _n O _n-1 (OC ₂ H ₅ ) _{2n + 2} Examples thereof include ethyl silicate 40 ^™ and ethyl silicate 45 ^™ .

Furthermore, as said silicic acid, what processed the alkali metal silicate, the silicate aqueous solution, such as a silicate of an organic base, with the cation exchange resin, and removed the alkali (removal of Na ion) can be used. Examples of the silicate include alkali metal silicates such as sodium silicate (water glass) and potassium silicate, and silicates of organic bases such as quaternary ammonium silicate. Among these, silicic acid having a pH of 2 to 6, preferably 2 to 3, and a silicon component content of 0.5 to 10% by weight, preferably 3 to 4% by weight, based on SiO ₂ It is desirable to use an aqueous solution (hereinafter sometimes referred to as “silicic acid aqueous solution”). Here, when the pH is less than 2, the treatment time required for cation exchange is unnecessarily long, and it is not economical, and when the pH exceeds 6, the degree of dealkalization is low, and thus obtained. Since the stability of silicic acid deteriorates, it is not preferable. Furthermore, when the content is less than 0.5% by weight, it is difficult to economically obtain the silica-based porous particles, and when the content exceeds 10% by weight, the stability of silicic acid is poor. This is not preferable. As the silicic acid aqueous solution having such properties, it is preferable to use a solution obtained by diluting water glass (sodium silicate) with water and then treating it with a cation exchange resin to dealkalize.

More specifically, after mixing at least one silicon compound selected from the silicon alkoxide and silicic acid into the mixed liquid containing the titanium-based fine particles under stirring, the silicon compound is heated at a temperature of 60 to 250 ° C. It is preferable to perform dehydration and condensation polymerization by hydrolysis.
Here, when the temperature is less than 60 ° C., the dehydration / condensation reaction of the silicon oxide precursor (hydrolyzate) formed on the particle surface does not sufficiently occur. When the temperature exceeds 250 ° C., the solubility of the silicon oxide becomes too high, so that the coating layer formed on the particle surface peels off, This is not preferable because the stability of the dispersion containing the particles may decrease. In this case, since the mixed solution already contains alkali metal, quaternary ammonium, etc., it is not necessary to add a hydrolysis catalyst or the like from the outside.
Thereby, surface-coated titanium-based fine particles (secondary particles) in which the surface of the titanium-based fine particles is coated with a silica-based oxide such as silicon dioxide represented by the chemical formula SiO ₂ are obtained.

The surface-coated titanium-based fine particles obtained in this way have a weight ratio (S / C) of oxide conversion standards when the weight of the titanium-based fine particles is represented by C and the weight of the coating layer is represented by S. It is preferable that the silica-based oxide is coated on the surface of the titanium-based fine particles so as to be in the range of 1/100 to 50/100, preferably 5/100 to 30/100.
Here, when the weight ratio is less than 1/100 in terms of oxide, the photocatalytic activity of the finally obtained metal oxide fine particles may not be sufficiently suppressed, and the weight ratio is oxidized. If it exceeds 50/100 on the basis of physical conversion, the coating layer becomes thick and a desired refractive index may not be obtained.

In addition, the coating layer formed in this way is desired to have a refractive index that is 0.2 or more lower than the refractive index of the titanium-based fine particles contained in the metal oxide fine particles. Since the refractive index of the silica-based oxide is around 1.45, this condition can be satisfied easily.
Thus, by coating the surface of the titanium-based fine particles with the silica-based oxide, light scattering on the particle surface of the finally obtained metal oxide fine particles can be greatly suppressed. Thereby, the turbidity of the organic solvent-dispersed sol described below can be kept low.

Next, after the mixed aqueous solution containing the surface-coated titanium-based fine particles is cooled to room temperature, it is subjected to an ultrafiltration membrane device and concentrated to obtain a mixed aqueous solution having a solid 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 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. This is not preferable because the capillary tension acting on the substrate increases and a hard dry powder (that is, a dry powder that is difficult to be pulverized in a subsequent pulverization step) is easily formed. 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.

Step (c)
In this step, the surface-coated titanium fine particles (secondary particles) contained in the mixed aqueous solution obtained above are dried and granulated to obtain a surface-coated titanium fine particle aggregate having an average particle diameter of 1 to 80 μm ( Tertiary particles).
Here, the surface-coated titanium-based fine particle aggregate can be obtained by subjecting the mixed aqueous solution to a general hot air drying apparatus, but is usually obtained as a lump-like dry solid, and is therefore subjected to a subsequent baking step. Prior to this, it is necessary to use a pulverizer to pulverize appropriately. However, not only is the operation complicated, but it becomes difficult to obtain a group of particles having a uniform particle diameter in the pulverization step performed after the firing step, so the mixed aqueous solution is spray-dried using a spray dryer. It is preferable. 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 mixed aqueous solution 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.
Thereby, a dried surface-coated titanium-based fine particle aggregate having an average particle diameter of 1 to 80 μm, preferably 2 to 60 μm is obtained.
Furthermore, the composite oxide particles can be freeze-dried using freeze-drying equipment or the like instead of the spray dryer.

Step (d)
In this step, the surface-coated titanium-based particle aggregate (tertiary particles) obtained above is fired at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain a fired product of the surface-coated titanium-based particle aggregate. .
More specifically, in this step, the surface-coated titanium-based particle aggregate is subjected to a baking apparatus, and is heated to 300 to 800 ° C., preferably 300 to 700 ° C. in an oxygen-containing atmosphere such as air. It is necessary to bake for a minute, preferably 60 to 180 minutes.
Here, if the firing temperature is less than 300 ° C., the crystallization of titanium-based fine particles contained in the fired product of the surface-coated titanium-based particle aggregate is difficult to proceed, and thus has a desired X-ray diffraction crystallite diameter. When it becomes difficult to obtain particles and the temperature exceeds 800 ° C., the sintering of the particles (that is, the sintering of the secondary particles) proceeds rapidly. Since it becomes difficult to obtain uniform particles, firing is preferably performed at a temperature appropriately selected from the above range. 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.

As a result, titanium-based fine particles (components of the surface-coated titanium-based particles) having an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm, preferably 8.0 to 10 nm, that is, the crystallinity is relatively high. A fired product of a surface-coated titanium-based particle aggregate containing titanium-based fine particles is obtained.
More specifically, since the crystallinity of the titanium-based fine particles increases when the firing operation is performed, the crystalline titanium-based particles having the X-ray diffraction crystallite diameter and having a rutile crystal structure. Can be obtained.
Here, if the X-ray diffraction crystallite diameter is less than 7.5 nm, the crystallinity of the particles becomes low, 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 particle becomes too high and light scattering on the particle surface increases. Therefore, when the X-ray diffraction crystallite diameter is less than 7.5 nm, it is necessary to increase the firing temperature within the above-mentioned firing temperature range, and the crystallite diameter is 14.0 nm. In the case where a product exceeding 1 is obtained, it is necessary to lower the firing temperature.

The titanium-based fine particles themselves have a high refractive index and a low photocatalytic activity, and the refractive index is in the range of 2.2 to 2.7, preferably 2.3 to 2.6. .
Here, 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. If the refractive index cannot be obtained and the refractive index exceeds 2.7, light scattering on the particle surface increases, which is not preferable. Therefore, 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.

Step (e)
In this step, the fired product of the surface-coated titanium-based particle aggregate obtained above is pulverized in the presence of an organic solvent, and the average particle diameter when measured by a dynamic light scattering method is 8 to 60 nm. An organic solvent-dispersed sol is obtained in which the metal oxide fine particles are further dispersed in an organic solvent. The metal oxide fine particles referred to here are surface-coated titanium-based fine particles (quaternary particles having a particle diameter substantially the same as or similar to the surface-coated titanium-based fine particles (secondary particles) except for some coarse particles. Particle).
More specifically, since the fired product of the surface-coated titanium-based particle aggregate obtained from the step (d) is a particle having a relatively large particle size with an average particle size of 1 to 80 μm, It is necessary to pulverize into fine particles having a particle size small enough to be solated (however, these particles may contain coarse particles of 100 nm or more).
As the pulverizer, a conventionally known pulverizer such as a sand mill, a roll mill, a bead mill, an ultrasonic disperser, an optimizer ^™ , a nanomizer ^™, or the like can be used. The operating conditions of the pulverizer vary depending on the pulverizer to be used and the properties of the fired product (that is, the fired product of the surface-coated titanium-based particle aggregate). For example, sand mill (manufactured by Kansai Paint Co., Ltd.) When using a tabletop sand mill, etc., a fired product of spherical quartz beads having a particle diameter of 0.1 to 0.2 mm and the surface-coated titanium-based particle aggregate is placed in an apparatus equipped with a ceramic disk rotor or the like. A mixed liquid (solid content concentration of 5 to 40% by weight) suspended in an organic solvent is added and pulverized under general conditions (for example, rotor rotation speed 600 to 2000 rpm, treatment time 1 to 10 hours, etc.) It is preferable to carry out the treatment.

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 -Organic compounds selected from ketones such as butyrolactone. Among these, when the obtained organic solvent-dispersed sol is used for an optical substrate such as a plastic lens, 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.
The organic solvent used when the fired product of the surface-coated titanium-based particle aggregate is pulverized has a solid content concentration of 10 to 45% by weight, preferably 20 to 40% by weight. It is preferable to add it in a crushing apparatus such as a sand mill in a proportion.
Here, if the solid content concentration of the calcined product is less than 10% by weight, the collision frequency of the calcined product decreases, so it takes a very long time to obtain a dispersion with a desired particle size, which is economical. When the solid content concentration of the fired product exceeds 45% by weight, it becomes difficult to obtain a dispersion with a desired particle size because the viscosity of the dispersion becomes too high and its fluidity decreases. It is not preferable.

Furthermore, when the fired product of the surface-coated titanium-based particle aggregate is pulverized using a pulverizer such as a sand mill, an organic compound such as a carboxylic acid compound or an amine compound that acts as a dispersion stabilizer is dissolved. It is preferable to grind in the presence of an organic solvent.
Examples of the carboxylic acid compounds include formic acid, acetic acid, succinic acid, acrylic acid (unsaturated carboxylic acid), monocarboxylic acid and monocarboxylic acid salt such as gluconic acid, malic acid, oxalic acid, malonic acid, succinic acid, glutaric acid. , Adipic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, and other polycarboxylic acids and carboxylic acid salts, tartaric acid, glyceric acid, glycolic acid, citric acid, malic acid, tropic acid, benzylic acid, Examples include α-lactic acid, β-lactic acid, and hydroxycarboxylic acid and hydroxycarboxylate of γ-hydroxyvaleric acid. Among these, it is preferable to use tartaric acid, citric acid, malic acid and the like from the viewpoint of transparency and dispersion stability of the organic solvent dispersion of the metal oxide fine particles finally obtained.
Further, the amine compounds include ammonia; alkylamines such as diisopropylamine, ethylamine, diethylamine, triethylamine, diisobutylamine, n-propylamine, aralkylamines such as benzylamine, alicyclic amines such as piperidine, monoethanolamine , Alkanolamines such as triethanolamine, quaternary ammonium salts such as tetramethylammonium salt and tetramethylammonium hydroxide, and quaternary ammonium hydroxides. Among these, it is preferable to use diisopropylamine, diisobutylamine, tetramethylammonium hydroxide, etc. from the viewpoint of transparency and dispersion stability of the organic solvent-dispersed sol of the finally obtained metal oxide fine particles.
Moreover, although the said carboxylic acid type compound and the said amine type compound can be used individually, it is preferable to use both (for example, tartaric acid and diisopropylamine). The reason is that by forming a double salt with metal ions etc. present on the surface of the crushed surface-coated titanium-based particles, the transparency and dispersion stability of the organic oxide-dispersed sol of the metal oxide fine particles finally obtained It is because it can improve. In addition, when using both of these compounds, it is not necessary to concern about the addition order.

The carboxylic acid compound is preferably mixed at a ratio of 5 to 40% by weight, preferably 10 to 30% by weight, based on the weight of the fired product of the surface-coated titanium-based particle aggregate.
Here, when the mixing amount of the carboxylic acid compound is less than 5% by weight, the transparency of the organic solvent-dispersed sol of the metal oxide fine particles finally obtained tends to deteriorate, and the mixing amount is 40%. If it exceeds wt%, the pulverized surface-coated titanium-based particles are likely to aggregate, and the dispersion stability of the organic solvent-dispersed sol of the finally obtained metal oxide fine particles may be deteriorated. .
Further, the amine compound is preferably mixed in a proportion of 1 to 40% by weight, preferably 5 to 30% by weight, based on the weight of the fired product of the surface-coated titanium-based particle aggregate.
Here, when the mixing amount of the amine compound is less than 1% by weight, the transparency of the organic solvent-dispersed sol of the metal oxide fine particles finally obtained tends to deteriorate, and the mixing amount is 40% by weight. If the ratio exceeds 50%, the pulverized surface-coated titanium-based particles tend to aggregate, and the dispersion stability of the organic solvent-dispersed sol of the finally obtained metal oxide fine particles may be deteriorated.

A desired amount of an organic solvent is further added to the suspension containing the metal oxide fine particles obtained above to prepare an organic solvent-dispersed sol. In addition, it is preferable to use the same kind as the organic solvent used above as the organic solvent used here.
Thereby, the organic solvent dispersion | distribution sol containing the metal oxide microparticles | fine-particles whose average particle diameters measured by a dynamic light scattering method are 8-60 nm is obtained.
Here, when the average particle diameter is less than 8 nm, when the metal oxide fine particles are dispersed in an organic solvent at a high concentration, the viscosity of the sol tends to increase remarkably, and the average particle diameter is 60 nm. If it exceeds, the light scattering on the particle surface increases, and as a result, the turbidity of the organic solvent-dispersed sol containing the metal oxide fine particles may increase. Is preferred.

Further, the metal oxide fine particles obtained in this way are obtained by coating the surface of crystalline titanium-based fine particles having a rutile-type crystal structure with a silica-based oxide, and the specific surface area is 70 to 200 m. ² / g, preferably in the range of 80 to 180 m ² / g, and the refractive index is in the range of 2.0 to 2.5, preferably 2.1 to 2.4.
Here, when the specific surface area of the metal oxide fine particles is less than 70 m ² / g, adhesion with a binder component contained in a coating composition prepared using the fine particles (with respect to OH groups present on the particle surface) In other words, the strength of the resulting curable coating film decreases, and as a result, it may be necessary to increase the amount of the particles added to the coating composition. In addition, when the specific surface area exceeds 200 m ² / g, the amount of OH groups present on the particle surface increases and the interaction between particles becomes strong, and as a result, the particles may agglomerate. Since transparency of a curable coating film may become low, it is not preferable.
Furthermore, when a metal oxide fine particle having a refractive index of less than 2.0 is obtained, it becomes difficult to form a desired high refractive index coating film (for example, a coating film for an optical substrate). It is necessary to make the coating layer thinner. In addition, when a material having a refractive index exceeding 2.5 is obtained, it may be difficult to suppress light scattering on the particle surface. Therefore, it is necessary to increase the thickness of the coating layer.

Step (f)
In this step, the organic solvent-dispersed sol obtained above is used in a wet classifier as necessary 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.
More specifically, since the metal oxide fine particles are produced by pulverization or pulverization / peptization as described above, the particle group may include coarse particles having a relatively large particle diameter. is there. Therefore, when such coarse particles are included, the organic solvent-dispersed sol containing the metal oxide fine particles is subjected to a wet classifier to measure coarse particles having a particle diameter of 100 nm or more when measured by a dynamic light scattering method. At least it must be separated and removed. 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.

The separation / removal of the coarse particles is a particle size frequency distribution when the obtained metal oxide fine particles are measured by a dynamic light scattering method, and the distribution frequency of coarse particles having a particle size of 100 nm or more is 1% or less, It is preferable to carry out so that it may become 0.2% or less preferably.
Here, when the distribution frequency of the coarse particles exceeds 1%, the organic solvent-dispersed sol of the metal oxide fine particles containing such coarse particles may have a turbidity exceeding 10 cm ⁻¹ , which is subtracted. Therefore, the transparency of the coating film obtained from the coating liquid for forming a coating film prepared using the organic solvent-dispersed sol may be lowered. Therefore, such coarse particles should be separated and removed as much as possible. It is desirable.
Thereby, metal oxide fine particles having an average particle diameter of 8 to 60 nm, preferably 10 to 50 nm, as measured by a dynamic light scattering method are obtained.

  In the organic solvent-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 chlorides Anionic substances such as ions, sulfate ions, nitrate ions, silicate ions, stannate ions, titanate ions are included. Therefore, it is desirable to remove the ionized substance as much as possible by adding an anion exchange resin or a cation exchange resin to the organic solvent-dispersed sol as necessary and stirring for an appropriate time. In addition, although the standard which removes the said ionized substance beforehand also changes with uses of the said organic solvent dispersion | distribution sol, the total ion concentration of the said ionization substance contained in this organic solvent dispersion | distribution sol will be 0.1 mol / L or less. Is preferably performed. Here, when the total ion concentration exceeds 0.1 mol / L, the aggregation of the metal oxide fine particles tends to occur, which is not preferable.

Preparation method-2
The second method for preparing an organic solvent-dispersed sol according to the present invention (hereinafter referred to as “Preparation Method-2”) is as follows.
A method for preparing an organic solvent-dispersed sol containing high refractive index metal oxide fine particles obtained by coating at least the surface of a composite oxide particle containing titanium and tin and / or silicon with a silica-based composite oxide,
(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. A step of generating titanium-based fine particles (primary particles) made of a complex oxide;
(B) In the mixed aqueous solution containing the titanium-based fine particles obtained in the step (a), at least one silicon compound selected from silicon alkoxide and silicic acid, zirconate peroxide, antimonate, and stannic acid A surface of the titanium-based fine particles is coated with a silica-based composite oxide by mixing at least one metal compound selected from a salt and an aluminate and hydrolyzing the silicon compound and the metal compound. A step of obtaining surface-coated titanium-based fine particles (secondary particles),
(C) a step of obtaining a surface-coated titanium-based fine particle aggregate (tertiary particles) having an average particle diameter of 1 to 80 μm by drying and granulating the surface-coated titanium-based fine particles obtained in the step (b),
(D) A step of baking the surface-coated titanium-based particle aggregate obtained in the step (c) at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain a fired product of the surface-coated titanium-based particle aggregate. ,
(E) The fired product of the surface-coated titanium-based particle aggregate obtained in the step (d) is pulverized in the presence of an organic solvent, and the average particle size when measured by a dynamic light scattering method is 8 to 60 nm. A step of obtaining an organic solvent-dispersed sol obtained by further dispersing the metal oxide fine particles (quaternary particles) in an organic solvent, and (f) the organic solvent dispersion obtained in the step (e). The liquid is subjected to a wet classifier as necessary, and includes a step 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.
That is, the difference between this preparation method-2 and the above preparation method-1 is only the operating conditions of the step (b). Therefore, only the step (b) will be described here.

Step (a) and Steps (c) to (f)
As described in Preparation Method-1.
Step (b)
In this step, in the mixed aqueous solution containing the titanium-based fine particles (primary particles) obtained in the step (a), 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 mixed, and the surface of the titanium-based fine particles is silica-based composite oxidized by hydrolyzing the silicon compound and the metal compound. Surface-coated titanium-based fine particles (secondary particles) obtained by coating with an object are obtained.

More specifically, in the mixed aqueous solution obtained in the step (a), at least one silicon compound selected from silicon alkoxide and silicic acid, zirconate peroxide, antimonate, stannate and aluminate. After mixing at least one metal compound selected from acid salts, the silicon compound and the metal compound are preferably hydrolyzed under a temperature condition of 60 to 250 ° C.
Here, when the temperature is less than 60 ° C., the dehydration / condensation reaction of the silicon oxide precursor (hydrolyzate) formed on the particle surface does not sufficiently occur. When the temperature exceeds 250 ° C., the solubility of the silicon oxide becomes too high, so that the coating layer formed on the particle surface peels off, This is not preferable because the stability of the dispersion containing the particles may decrease. In this case, since the mixed solution already contains alkali metal, quaternary ammonium, etc., it is not necessary to add a hydrolysis catalyst or the like from the outside.
The silicon alkoxide is preferably tetramethoxysilane or a condensate thereof, or tetraethoxysilane or a condensate thereof as in Preparation Method-1. Moreover, the said silicic acid can use what was described in the preparation method-1.

As a result, surface-coated titanium-based fine particles in which the surface of the titanium-based fine particles is coated with a silica-based composite oxide containing silicon and at least one metal element selected from zirconium, antimony, tin, and aluminum are obtained. .
Here, the silica-based composite oxide is a compound containing silicon and at least one metal element selected from zirconium, antimony, tin, and aluminum. A part of these compounds can be schematically shown by a chemical formula. Is 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 surface-coated titanium-based fine particles obtained in this way have a weight ratio (S / C) of oxide conversion standards when the weight of the titanium-based fine particles is represented by C and the weight of the coating layer is represented by S. It is preferable to coat the silica-based composite oxide on the surface of the titanium-based fine particles so that the range is 1/100 to 50/100, 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.

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 organic solvent-dispersed sol described below can be kept low.

The refractive index of the metal oxide fine particles obtained by subjecting the mixed aqueous solution containing the surface-coated titanium-based fine particles to the subsequent steps (c) to (f) is the same as the thickness of the coating layer as in Preparation Method-1. Is as thin as 1 nm or less, more specifically about 0.1 to 0.5 nm (however, detailed values cannot be measured), and thus is almost the refractive index of the titanium-based fine particles. ing. 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.

  Also, in the organic solvent-dispersed sol of the metal oxide fine particles obtained in this manner, as in the case of Preparation Method-1, ionized substances added or by-produced in the above preparation process, such as potassium ions, Examples include cationic substances such as sodium ion, ammonium ion, tin ion and titanium ion, and anionic substances such as chloride ion, sulfate ion, nitrate ion, silicate ion, stannate ion and titanate ion. Therefore, it is desirable to remove the ionized substance in advance as in Preparation Method-1.

The organic solvent-dispersed sol containing the metal oxide fine particles obtained by the above preparation method-1 and preparation method-2 contains 5-40% by weight, preferably 10-30% by weight of the metal oxide fine particles, and further its turbidity. The degree is in the range of 0.1 to 11.0 cm ⁻¹ , preferably 0.2 to 9.0 cm ⁻¹ .
Here, the content of the metal oxide fine particles is almost determined by the addition amount when the metal oxide fine particles pulverized in the step (e) are dispersed in an organic solvent, but the content exceeds 40% by weight. In this case, the stability of the organic solvent-dispersed sol is deteriorated due to an increase in viscosity and the like.

On the other hand, the turbidity of the organic solvent-dispersed sol is substantially determined by the light scattering rate of the metal oxide fine particles and the content thereof, but it is difficult to obtain a turbidity of less than 0.1 cm ^−1. When the turbidity exceeds 10.0 cm ⁻¹ , the transparency of the coating film obtained from the coating liquid for forming a coating film prepared using the organic solvent-dispersed sol may be remarkably deteriorated. .
As described above, when the turbidity of the organic solvent-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. There is. In addition, since this problem can sometimes be solved by reducing the average particle diameter of the metal oxide fine particles, in some cases, a metal oxide obtained by pulverizing the fired product of the surface-coated titanium-based particle aggregate. It is desirable to reduce the average particle size of the fine particles, or remove the coarse particles contained in the metal oxide fine particles as much as possible in the subsequent wet classification step.
Thus, the organic solvent dispersion sol of the high refractive index metal oxide fine particles according to the present invention is obtained.

Usually, when an organic solvent dispersion sol is prepared by subjecting the water dispersion sol to a solvent displacement device and replacing the water contained in the water dispersion sol with an organic solvent, the water dispersion sol is contained in advance in the water dispersion sol. Although it is desirable to treat the surface of the metal oxide fine particles with a surface treatment agent such as an organosilicon compound or an amine compound, it is not necessary to perform this treatment in the present invention. This is because the carboxylic acid compound or the amine compound added to the organic solvent in the step (e), that is, the pulverization step of the surface-coated titanium-based particle aggregate baked product plays the role.
In the present invention, since the step of preparing the water-dispersed sol of the high refractive index metal oxide fine particles is not included, the above-described solvent replacement device is not used when preparing the organic solvent-dispersed sol.

[Organic solvent dispersion sol]
The organic solvent dispersion sol of the high refractive index metal oxide fine particles according to the present invention is:
An organic solvent-dispersed sol of metal oxide fine particles having a high refractive index obtained from the preparation method according to any one of the above,
(1) The titanium-based fine particles constituting the metal oxide fine particles are crystalline particles having a rutile-type crystal structure, and have an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm. The refractive index is in the range of 2.2 to 2.7,
(2) The coating layer constituting the metal oxide fine particles has a refractive index lower by 0.2 or more than the refractive index of the titanium-based fine particles, and (3) the metal oxide fine particles have an average of 8 to 60 nm. It has a particle diameter and a specific surface area of 70 to 200 m ² / g, and its refractive index is in the range of 2.0 to 2.5. (4) The organic solvent-dispersed sol is 5 to 40% by weight. The metal oxide fine particles are included, and the turbidity is in the range of 0.1 to 11.0 cm ⁻¹ .

As described above, the titanium-based fine particles constituting the metal oxide fine particles contained in the organic solvent-dispersed sol are crystalline particles having a rutile-type crystal structure and 7.5 to 14.0 nm. It is desirable that the X-ray diffraction crystallite diameter be in the range of 2.2 to 2.7.
Here, if the X-ray diffraction crystallite diameter is less than 7.5 nm, the crystallinity of the particles becomes low, 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 particle becomes too high and light scattering on the particle surface increases. 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.

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.

The coating layer constituting the metal oxide fine particles contained in the organic solvent-dispersed sol has a refractive index lower than the refractive index of the titanium-based fine particles by 0.2 or more, preferably 0.5 or more. It is hoped that.
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.
As described above, the coating layer having such a refractive index is at least one selected from silica-based oxides substantially composed of silicon dioxide, silicon, zirconium, antimony, tin, and aluminum. It is preferably composed of a silica-based composite oxide containing a seed metal element.

The metal oxide fine particles provided with the coating layer have an average particle diameter of 8 to 60 nm, a specific surface area of 70 to 200 m ² / g, and a refractive index of 2.0 to 2.5. It is desirable that
Here, when the average particle diameter of the metal oxide fine particles is less than 8 nm, when the metal oxide fine particles are dispersed at a high concentration in an organic solvent, the viscosity of the sol tends to be remarkably increased. When the average particle diameter exceeds 60 nm, light scattering on the particle surface increases, and as a result, the turbidity of the organic solvent-dispersed sol containing the metal oxide fine particles may increase, which is not preferable. Further, when the specific surface area of the metal oxide fine particles is less than 70 m ² / g, adhesion with a binder component contained in a coating composition prepared using the fine metal oxide particles (reaction with OH groups present on the particle surface) The strength of the resulting curable coating film is reduced, and as a result, it may be necessary to increase the amount of the particles added to the coating composition. In addition, when the specific surface area exceeds 200 m ² / g, the amount of OH groups present on the particle surface increases and the interaction between particles becomes strong, and as a result, the particles may agglomerate. Since transparency of a curable coating film may become low, it is not preferable. Furthermore, 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 organic solvent-dispersed sol containing the fine particles is 1. When the refractive index is more than 2.5, it is difficult to make it 70 or more, and hardness sufficient for a coating film obtained from a coating liquid for coating film formation prepared using an organic solvent-dispersed sol containing the fine particles If an amount necessary for providing (that is, appropriate hard coat characteristics) is added, the refractive index of the coating film becomes excessively high and interference fringes are easily generated, which is not preferable.

The organic solvent-dispersed sol containing the metal oxide fine particles contains 5 to 40% by weight, preferably 10 to 30% by weight of the metal oxide fine particles, and has a turbidity of 0.1 to 11.0 cm ⁻¹ , preferably Is desirably in the range of 0.2 to 9.0 cm ⁻¹ .
Here, when the content of the metal oxide fine particles exceeds 40% by weight, an increase in viscosity occurs and the stability of the organic solvent-dispersed sol is deteriorated, which is not preferable. Furthermore, it is difficult to obtain a turbidity of the organic solvent-dispersed sol of less than 0.1 cm ⁻¹ , and when the turbidity exceeds 11.0 cm ⁻¹ , the organic solvent-dispersed sol was prepared using the organic solvent-dispersed sol. Since the transparency of the coating film obtained from the coating liquid for forming a coating film may be remarkably lowered, it is not preferable.

Further, when the organic solvent-dispersed sol is used for an optical base material such as a plastic lens, the content of the metal oxide fine particles is 10 depending on the kind of the organic solvent contained in the dispersed sol. It is preferable to make it in a range of ˜40% by weight, preferably 20-30% 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 deteriorates as described above, which is not preferable.
Further, the metal oxide fine particles contained in the organic solvent-dispersed sol have a distribution frequency of relatively coarse titanium-based fine particles having a particle diameter of 100 nm or more in a particle diameter frequency distribution measured by a dynamic light scattering method. Is preferably 1% or less.
Here, when the distribution frequency of the coarse particles exceeds 1%, as described above, the organic solvent-dispersed sol of the metal oxide fine particles containing such coarse particles has a turbidity exceeding 11.0 cm ^−1. It is not preferable because it may become higher.

  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 organic solvent dispersion sol of the high refractive index metal oxide fine particles according to the present invention can be used for other applications, the organic solvent dispersion sol according to the present invention is not limited to these applications. Absent.

[Coating composition]
The coating composition according to the present invention comprises high refractive index metal oxide fine particles obtained from the above-described method of the present invention and a binder component.
Here, since the high refractive index metal oxide fine particles are as described above, the binder component will be specifically described as follows.
(1) Binder Component The binder component used in the present invention can be appropriately selected from conventionally known ones or those currently under development according to the purpose of use of the coating composition. However, here, a typical binder component used in the coating composition for optical articles will be specifically described. That is, (b) a thermosetting organic resin or (c) a thermoplastic organic resin used in (a) an organosilicon compound and a primer layer film forming coating composition used for hard coat layer film forming paints, etc. Will be described in detail.
However, the binder component used in the present invention is not necessarily limited to these as long as it functions as the binder component of the high refractive index metal oxide fine particles. For example, instead of the organosilicon compound, a compound such as a metal alkoxide such as titanium alkoxide or an ultraviolet curable compound (for example, a polyfunctional acrylic compound having an acryloyloxy group), the thermosetting organic resin, In place of the thermoplastic organic resin, a compound such as the ultraviolet curable compound may be used.

(A) Organosilicon compound The organosilicon compound as the binder component used in the present invention is preferably an organosilicon compound represented by the following general formula (I) and / or a hydrolyzate thereof.
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.

(B) Thermosetting organic resin The thermosetting organic resin as the binder component used in the present invention is preferably at least one selected from urethane resins, epoxy resins and melamine resins. .
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.
Furthermore, examples of the melamine-based resin include cured products of etherified methylol melamine, polyester polyol, and 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. Moreover, these thermosetting organic resins may use not only one type but also two or more types.

(C) Thermoplastic organic resin The thermoplastic organic resin as the binder component used in the present invention is preferably at least one selected from an acrylic resin, a urethane resin and an ester resin. A self-emulsifying aqueous emulsion resin is more preferable.
More specifically, examples of the acrylic resin include a water-based emulsion obtained from a (meth) acrylic acid alkyl ester monomer and a polymer emulsion obtained by copolymerizing the monomer with styrene, acrylonitrile, and the like. Examples of the urethane resin include water-based emulsions obtained by reacting a polyol compound such as polyester polyol, polyether polyol, and polycarbonate polyol with polyisocyanate. Further, examples of the ester resin include hard segments. Examples include polyester, water-dispersed elastomer of a multi-block copolymer using polyether or polyester as a 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 organic resins may use not only one type but also two or more types.

(2) Coating composition Next, the coating composition containing the high refractive index metal oxide fine particles and the binder component will be described more specifically. That is, a coating composition containing the organosilicon compound as the binder component (hereinafter sometimes referred to as “coating composition-1”), and the thermosetting organic resin or the thermoplastic organic resin as the binder component. More specifically, the coating composition to be included (hereinafter sometimes referred to as “coating composition-2”) is as follows.

Coating composition-1
In preparing the coating composition-1 according to the present invention, the organosilicon compound is partially hydrolyzed or hydrolyzed in the presence of an acid and water in the absence of a solvent or in a polar organic solvent such as alcohol, It is preferable to mix with the organic solvent dispersion sol containing the high refractive index metal oxide fine particles. However, the organosilicon compound may be partially hydrolyzed or hydrolyzed after mixing with the organic solvent-dispersed sol.

Thus, the coating composition-1 is prepared by mixing the organosilicon compound and / or the hydrolyzate thereof with the organic solvent-dispersed sol containing the high refractive index metal oxide fine particles. As for the mixing ratio, when the weight of the organosilicon compound converted to SiO ₂ is represented by X and the weight of the high refractive index metal oxide fine particles is represented by Y, the weight ratio (X / Y) is 30/70. It is preferable to be in the range of ˜90 / 10, preferably 35/65 to 80/20. Here, when the weight ratio is less than 30/70, the adhesiveness with an optical substrate or another coating film (for example, primer layer film) may be lowered, and the weight ratio is 90/10. If it exceeds, the refractive index of the coating film and the scratch resistance on the coating film surface will be low, which is not preferable.
The coating composition-1 thus prepared can be suitably used as a coating composition for forming a hard coat layer film.

In addition, the coating composition-1 includes the above-described components in order to improve the dyeability of a coating film such as a hard coat layer film and the adhesion to a plastic lens substrate, and to prevent the occurrence of cracks. In addition, it may contain an uncrosslinked epoxy compound.
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 composition-1 is composed of components other than those described above, such as surfactants, leveling agents and / or ultraviolet absorbers, as well as 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 composition-2
The coating composition-2 according to the present invention is prepared by mixing the thermosetting organic resin or the thermoplastic organic resin and the organic solvent-dispersed sol of the high refractive index metal oxide fine particles.
The mixing ratio varies depending on the type of the resin compound (that is, the thermosetting organic resin or the thermoplastic organic resin) and the use of the coating composition, but the weight of the resin compound is represented by A, and When the weight of the high refractive index metal oxide fine particles is represented by B, the weight ratio (A / B) is preferably in the range of 90/10 to 30/70, preferably 80/20 to 35/65. Here, when the weight ratio is less than 30/70, the adhesion between the coating film (primer layer film) formed from the coating composition and the hard coat layer film formed on the surface thereof may be reduced. In addition, when an antireflection layer film is formed on the surface of the hard coat layer film, the impact resistance of the obtained optical lens substrate may be deteriorated. Furthermore, when the weight ratio exceeds 90/10, not only the heat resistance of the coating film (primer layer film) formed from this coating composition may deteriorate, but also the refractive index of the coating film decreases. This is not preferable.
The coating composition-2 thus prepared can be suitably used as a coating composition for optical substrates (particularly, a coating composition for forming a primer layer film).

  Furthermore, the coating composition-2 is composed of components other than those described above, such as neutralizers, surfactants or ultraviolet absorbers, and organic compounds described in conventionally known documents such as International Publication WO2007 / 026529. An inorganic compound or the like may be included.

(3) Preparation method of coating composition Next, the preparation method of the coating composition-1 which concerns on this invention, and the coating composition-2 is demonstrated concretely. As described above, these coating composition-1 and coating composition-2 were prepared by preparing an organic solvent dispersion sol containing high refractive index metal oxide fine particles, and then preparing the organosilicon compound (that is, the coating composition). Component-1), or mixed with the thermosetting resin or thermoplastic resin (that is, the component of paint composition-2). Here, the paint composition used for the optical substrate is used. The method for preparing the product will be specifically described. However, since the preparation method described here shows the one aspect | mode, the coating composition which concerns on this invention is not limited to what was 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. Say things.

Coating composition-1
The coating composition-1 which concerns on this invention is prepared by mixing the organic solvent dispersion | distribution sol of the high refractive index metal oxide fine particle obtained above, and an organosilicon compound.
As mentioned above, the organosilicon compound used here is preferably an organosilicon compound represented by the following general formula (I) and / or a hydrolyzate thereof.
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.)
In addition, specific examples of the organosilicon compound are as described above.

In the preparation of the coating composition-1, the organic silicon 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, and then the organic solvent-dispersed sol It is preferable to mix with. However, the organosilicon compound may be partially hydrolyzed or hydrolyzed after mixing with the organic solvent-dispersed sol.
The partial hydrolysis or hydrolysis of the organosilicon compound is preferably performed at a temperature of 5 to 30 ° C. for 1 to 48 hours while stirring. Moreover, after hydrolyzing, it may be allowed to stand under a low temperature condition of -10 to 1 ° C for aging.
Thus, the coating composition-1 is prepared by mixing the organosilicon compound and the organic solvent-dispersed sol, and the mixing is based on the weight of the organosilicon compound converted to SiO ₂ as X When the weight of the high refractive index metal oxide fine particles is represented by Y, the weight ratio (X / Y) is 30/70 to 90/10, preferably 35/65 to 80/20. Preferably it is done. Here, when the weight ratio is less than 30/70, as described above, the adhesion to the substrate or other coating film may be lowered, and the weight ratio is 90/10. If it exceeds, the refractive index of the coating film and the scratch resistance on the surface of the coating film may be deteriorated.

The coating composition-1 thus prepared is suitably used as a coating composition for optical substrates. A representative example of the coating composition for optical substrates is a coating composition for forming a hard coat layer film.
When preparing the coating composition-1 as a coating composition for an optical substrate, alcohols such as methanol and ethanol and ethers such as propylene glycol monomethyl ether are used as a dispersion medium for the organic solvent dispersion sol. Is preferred. Further, the dispersion medium of the organosilicon compound can be used without particular limitation as long as it is compatible with the dispersion medium of the organic solvent dispersion sol, but it is preferable to use the same kind as possible.

Further, the coating composition-1 has the above-described properties in order to improve the dyeability of a coating film such as a hard coat layer film and the adhesion to a plastic lens substrate, and to prevent the occurrence of cracks. In addition to the components, an uncrosslinked epoxy compound or the like may be included.
Furthermore, the coating composition-1 contains components other than those described above, for example, surfactants, leveling agents and / or ultraviolet absorbers, and conventionally known organic compounds and inorganic compounds suitable for the application. Also good.

Coating composition-2
The coating composition-2 according to the present invention is prepared by mixing the organic solvent dispersion sol of the high refractive index metal oxide fine particles obtained above and a thermosetting resin or a thermoplastic resin.
Examples of the thermosetting resin used here include urethane resins, epoxy resins, melamine resins, and silicone resins. Among these, urethane resins and epoxy resins are preferably used. .
Examples of the thermoplastic resin include acrylic resins, urethane resins, and ester resins. Among these, urethane resins and ester resins are preferably used.
Specific examples of the thermosetting resin and the thermoplastic resin are as described above.

In the preparation of the coating composition-2, the organic solvent sol is added to a dispersion obtained by dissolving the thermosetting resin in an organic solvent or a dispersion obtained by dissolving or dispersing the thermoplastic resin in an organic solvent or water. It is preferable to mix. The dispersion medium of the thermosetting resin or the thermoplastic resin can be used without particular limitation as long as it is compatible with the dispersion medium of the organic solvent-dispersed sol. preferable. However, the thermosetting resin or the thermoplastic resin may be directly mixed into the organic solvent-dispersed sol without being dissolved or dispersed in a dispersion medium such as an organic solvent or water.
Thus, although the said coating composition-2 is prepared by mixing the said resin compound and the said organic solvent dispersion | distribution sol, the mixing changes also with the kind of the said resin compound, its use, etc., When the weight of the resin compound is represented by A and the weight of the high refractive index metal oxide fine particles is represented by B, the weight ratio (A / B) is 90/10 to 30/70, preferably 80/20 to It is preferable to carry out so that it may become 35/65. Here, if the weight ratio is less than 30/70, the adhesion to the substrate and other coating films and the impact resistance of the substrate may be lowered, and the weight ratio exceeds 90/10. And the refractive index and heat resistance of the coating film may decrease, which is not preferable.

The coating composition-2 thus prepared is suitably used as a coating composition for an optical substrate, as in the case of the coating composition-1. A typical example of the coating composition for an optical substrate is a coating composition for forming a primer layer film.
In addition, the coating composition-2 contains components other than those described above, such as neutralizing agents, surfactants or ultraviolet absorbers, and further conventionally known organic compounds and inorganic compounds suitable for the intended use. May be.

(4) Curable coating film The coating composition according to the present invention comprises a high dielectric material, an optical material, a high refractive index hard code material, a high refractive index adhesive material, a high refractive index sealing material, a high reflective material, and ultraviolet light. It can be used for various applications such as absorbent materials. However, here, as a typical example, a curable coating film obtained by applying the coating composition on an optical substrate, that is, a coating film for an optical substrate will be described.

As an optical substrate for applying the coating composition, there are various plastic substrates. When this is used as an optical lens, polystyrene resin, allyl resin (especially aromatic allyl resin), polycarbonate There is a plastic lens substrate made of 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 composition 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 composition is lowered, it has a relatively low refractive index of 1.50 to 1.70, more specifically 1.52 to 1.67. It can be easily applied to optical substrates.

Among the coating compositions, a coating composition for an optical substrate selected from the coating composition-2 (that is, a coating composition for forming a primer layer film) is applied onto the optical substrate by a conventionally known method. Directly applied. On the other hand, the coating composition for an optical substrate selected from the coating composition-1 (that is, the coating composition for forming a hard coat layer film) is directly applied onto the optical substrate by a conventionally known method. Alternatively, it is applied onto a coating film (that is, a primer layer film) formed by applying the coating composition for optical substrates.
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. However, if the hard coat layer film is directly formed on a plastic lens substrate made of polythioepoxy resin, the substrate may be discolored due to the physical properties of the substrate, or the hard In such a case, it is desirable to form the primer layer film in advance on the base material, since the adhesiveness with the coat layer film may deteriorate. This phenomenon is the same when a conventionally known coating composition for forming a hard coat layer film is used.

[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 size of particles 19.85 g of pure water was added to 0.15 g of water-dispersed sol or organic solvent sol (solid content 20% by weight) of titanium-based fine particles or metal oxide fine particles having a nano-sized particle size. A sample with a solid content of 0.15% prepared by mixing was 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 (Otsuka Electronics Co., Ltd.) using a dynamic light scattering method. ), Model size ELS-Z2), and 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.

(2) Particle size distribution frequency of particles The particle size distribution is obtained from the frequency distribution of the scattering intensity obtained from the particle size distribution measurement by the dynamic light scattering method used in (1) 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.

(3) Specific surface area of particles About 30 ml of dry powder of titanium-based fine particles or surface-coated titanium-based fine particles is collected in a magnetic crucible (type B-2), dried at a temperature of 300 ° C. for 2 hours, and then placed in a desiccator at room temperature. Allow to cool. 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.

(4) Crystal form of particles Titanium-based fine particles or surface-coated titanium-based fine particles of water-dispersed sol are collected in a magnetic crucible (type B-2), dried at 110 ° C. for 12 hours, placed in a desiccator and cooled 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.

(5) X-ray diffraction crystallite diameter of particle The particle size is determined from the result of measuring the crystal structure of titanium-based fine particles or surface-coated titanium-based fine particles (baked product) using the X-ray diffractometer used in (4). In addition, the X-ray diffraction crystallite diameter (D) as used in the field of this invention shows the value calculated 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).)

(6) Crystal plane spacing by X-ray diffraction Using the X-ray diffractometer used in (5) above, it is determined from the result of measuring the crystal structure of titanium-based fine particles or surface-coated titanium-based fine particles (baked product). 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.)

(7) Relative peak intensity by X-ray diffraction Obtained from the result of measuring titanium-based fine particles or surface-coated titanium-based fine particles (baked product) using the X-ray diffractometer used in (5) 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.

(8) Absorbance (log (I _o / I) at a wavelength of 500 nm of an organic solvent dispersed sol containing fine metal oxide particles using a turbidity spectrophotometer (V-550 manufactured by JEOL Ltd.) of the organic solvent dispersed sol. )) Is obtained from the measurement results. In this case, the organic solvent used in the preparation of the organic solvent dispersion sol 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.)

(9) Content of metal oxide contained in particles After collecting water-dispersed sol or organic solvent-dispersed sol (sample) containing titanium-based fine particles or metal oxide fine particles in zirconia balls, drying and firing, Na ₂ Add O ₂ and NaOH to melt. 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 (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.

(10) 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 water-dispersed sol or organic solvent-dispersed sol (solid concentration 2.0% by weight) containing fine particles or metal oxide fine particles, and Tris (2.4-pentanedionato) aluminum III (Tokyo Chemical Industry Co., Ltd.) And 0.07 g of a methanol solution containing 10% by weight of a silicone surfactant (manufactured by Toray Dow Corning Co., Ltd., L-7006) as a leveling agent was added at room temperature. Overnight stirring to the coating composition A (weight fraction of the 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.

Further, the coating composition was prepared in the same manner as described above except that the amount of the water-dispersed sol or organic solvent-dispersed sol was changed to 77.1 g, 115.6 g, 154.1 g, 192.7 g, and 212.0 g. B (weight fraction of particles: 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 ( Particle weight fraction: 50% by weight) and coating composition F (particle weight fraction: 55% by weight) are prepared, respectively.
For the water-dispersed sol or organic solvent-dispersed sol containing the metal oxide fine particles (solid content concentration 20.0% by weight), the mixing amount of the water-dispersed sol is 3.9 g, 7.7 g, 11.6 g, Coating composition A (particle weight fraction: 10% by weight), coating composition B (particle weight fraction) in the same manner as above except that the amount was changed to 15.4 g, 19.2 g and 21.2 g. Coating composition C (particle weight fraction: 30 wt%), coating composition D (particle weight fraction: 40 wt%), coating composition E (particle weight fraction: 50) % By weight) and coating composition F (particle weight fraction: 55% by weight).

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, it is the range of 1.70-2.31) of the particle | grains measured by the standard liquid method.

(11) 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. .

(12) Photocatalytic activity test of particles An organic solvent dispersion sol containing solid metal oxide fine particles (solid content 20 wt%) 0.66 g was prepared by mixing 9.34 g of pure water, and a solid content 6.6. 9.70 g of a glycerol solution of sunset yellow dye having a solid content of 0.02 wt% is mixed with 0.33 g of a wt% 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

(13) Light resistance test of particles A solid solution prepared by mixing 4.50 g of pure water and 12.6 g of methanol with 0.90 g of an organic solvent dispersion sol (solid content 20 wt%) containing metal oxide fine particles. 18.00 g of a sample having a content of 1.0% by weight is placed in a quartz cell having a length of 1 mm, a width of 1 cm, and a height of 5 cm and sealed. 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

(14) 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 a glare interference fringe.

(15) 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

(16) 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 D: Most flawed areas are scratched.

(17) Adhesion test of coating film The lens surface of the sample substrate on which the hard coat layer film is formed is cut with a knife at intervals of 1 mm to form 100 squares of 1 mm square, and the cellophane adhesive tape is strongly After pressing, the plastic lens substrate is suddenly pulled in the direction of 90 degrees with respect to the in-plane direction of the plastic lens substrate, and this operation is performed a total of 5 times.
Good: The number of cells not peeled is 95 or more. Bad: The number of cells not peeled is less than 95.

(18) 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.

(19) Light resistance test of coating film Irradiation with ultraviolet rays is performed for 50 hours with 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

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.
[Example 1]
(1) 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 (produced by Osaka Titanium Technologies Co., Ltd.) on a TiO ₂ basis, and ammonia A white slurry solution having a pH of 9.5 was prepared by mixing 4.69 kg of ammonia water (manufactured by Ube Industries, Ltd.) containing 15% by weight. 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, 4.70 kg of cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with 98.67 kg of the aqueous solution of titanic acid titanate, and potassium stannate (manufactured by Showa Kako Co., Ltd.) was converted into SnO _{2 in this.} 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 (Asahi Kasei Co., Ltd., ACV-3010), and the titanium-based fine particles having a solid content of 10% by weight ( Hereinafter, 9.90 kg of an aqueous dispersion sol containing “P-1” was obtained.
The solids contained in the sol thus obtained were measured by the above method. As a result, they were titanium-based fine particles (primary particles) having a rutile crystal structure and composed of a composite oxide containing titanium and tin. It was. Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, 87.2% by weight of TiO ₂ , 11.0% by weight of SnO ₂ , and K ₂ O1 based on the oxide conversion standard of each metal component. 0.8% by weight. The pH of the mixed aqueous solution was 10.0.

Further, the water-dispersed sol containing the titanium-based fine particles is transparent milky white, the average particle size of the titanium-based fine particles contained in the water-dispersed sol is 35 nm, and coarse particles having a particle size of 100 nm or more. The distribution frequency was 0%. Furthermore, the specific surface area of the obtained titanium-based fine particles was 124 m ² / g.
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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.557, 1.597, 1.654, 1.697, 1 .762, 1.782. 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 1.3. The refractive index of the particle showing × 10 ⁻³ and showing its minimum value was 2.42. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.42.

(2) Preparation of water-dispersed sol containing titanium-based fine particles surface-coated with silica-based oxide Next, the obtained water-dispersed sol of titanium-based fine particles P-1 (with a solid content of 10.0) (Weight%) After mixing 9.90 kg with pure water 28.37 kg and 5.0 wt% ammonia water 0.38 kg, the weight of the titanium fine particles is represented by C, and the weight of the coating layer is S In the case where the weight ratio (S / C) is 20/100 in terms of oxide, the amount of silicon component is 28% by weight in terms of SiO _{2 on the} basis of SiO ₂ (manufactured by Tama Chemical Co., Ltd.). 0.95 kg and 19.80 kg of methanol (Mayashi Junyaku Co., Ltd., methyl alcohol concentration: 99.9% by weight) were 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. Furthermore, 0.38 kg of a cation exchange resin (Mitsubishi Chemical Corporation) was mixed and stirred for 30 minutes. Next, the cation exchange resin is separated and removed using a stainless steel filter having an opening of 44 μm, and then concentrated using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013) to obtain a solid content. A 20% by weight aqueous dispersion sol was prepared. As a result, surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) formed by coating the surface of the titanium-based fine particles with a hydrolyzed condensate of normal ethyl silicate, that is, a silica-based oxide, are included. 5.82 kg of water dispersion sol was obtained.
Note that the refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.97 lower than the refractive index of the titanium-based fine particles.

Next, 5.82 kg of an aqueous dispersion sol containing the surface-coated titanium-based fine particles was applied to a spray dryer (NIRO ATOMIZER manufactured by NIRO) and spray-dried (inlet temperature: 260 ° C., outlet temperature: 55 ° C.). As a result, 1.16 kg of a surface-coated titanium-based fine particle aggregate (tertiary particle) having an average particle diameter of about 2 μm as a granular dried product was obtained.

Next, 1.16 kg of the surface-coated titanium-based fine particle aggregate obtained above was calcined for 1 hour at a temperature of 500 ° C. in an air atmosphere. Got.
The surface-coated titanium fine particles obtained by firing in this way had a specific surface area of 170 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile type crystal structure, and the X-ray diffraction crystallite diameter was 9.6 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the surface-coated titanium-based fine particle aggregate obtained was 0.53 kg of methanol (produced by Hayashi Junyaku Co., Ltd.), L-(+)-tartaric acid (produced by Kanto Chemical Co., Ltd.) The mixture was dispersed in a mixed solution consisting of 45.3 g and 29.7 g of diisopropylamine (manufactured by Tokyo Chemical Industry Co., Ltd.). Next, 1.00 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 the mixed solution, and the resulting mixture was mixed with a wet pulverizer (Kampe Co., Ltd. batch). The baked product of the surface-coated titanium-based fine particle aggregate was subjected to pulverization treatment for 180 minutes by using a tabletop sand mill. Thereafter, the quartz beads were separated and removed using a stainless steel filter having an opening of 44 μm, and methanol was further added and stirred to obtain about 1.55 kg of a methanol-dispersed sol having a solid content of 11% by weight. (Note that in this pulverization step, loss occurs due to adhesion to the silica beads and the pulverizer and the like, so the amount of metal oxide fine particles recovered is not always constant. The amount of methanol-dispersed sol also varies, but the approximate value is described here, and the same applies to the examples and comparative examples shown below.)
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. (The metal oxide fine particles mentioned here are surface-coated titanium-based fine particles (quaternary particles having a particle diameter substantially the same as or similar to the surface-coated titanium-based fine particles (secondary particles) except for some coarse particles). The metal oxide fine particles described in the following examples and comparative examples are also the same.) The average particle diameter of the metal oxide fine particles contained in the methanol-dispersed sol is 45 nm. The distribution frequency of coarse particles having a particle diameter of 100 nm or more was 12.0%.

Next, the methanol-dispersed sol containing the metal oxide fine particles was washed with 1.38 kg of methanol added from the outside using an ultrafiltration membrane (SIP-1013, manufactured by Asahi Kasei Co., Ltd.).
0.35 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with 1.55 kg of the methanol-dispersed sol containing the metal oxide fine particles thus obtained and stirred for 30 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and this methanol dispersion sol was subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.). Processing was performed at a speed of 000 rpm for 1 hour, and coarse particles having a particle diameter of 100 nm or more were classified and removed. As a result, 1.70 kg of a methanol-dispersed sol containing the metal oxide fine particles having a solid content of 6.5% by weight was obtained.
Next, 1.70 kg of methanol dispersion sol containing the metal oxide fine particles (solid content 6.5% by weight) is concentrated with an ultrafiltration membrane device (Asahi Kasei Co., Ltd., SIP-2013), Methanol-dispersed sol having a solid content of 20% by weight, that is, the surface-coated titanium-based fine particle aggregate is fired and pulverized, and coarse particles are classified and removed (hereinafter referred to as “DP-1”) 0.55 kg of methanol-dispersed sol containing.

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.5 cm ⁻¹ . The average particle size of the metal oxide fine particles contained in the methanol-dispersed sol was 36 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 0%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface thereof) was 170 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 70.8% by weight of TiO ₂ , 8.8% by weight of SnO ₂ , SiO ₂ 20 based on the oxide conversion standard 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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, and 55% by weight, 1.530, 1.566, 1.604, 1.650, 1 .702, 1.730. Furthermore, 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 9.4. The refractive index of the particles having × 10 ⁻⁶ and 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 1.

[Example 2]
(1) Preparation of water-dispersed sol containing titanium-based fine particles 11.37 kg of an aqueous titanium tetrachloride solution containing 7.75% by weight of titanium tetrachloride (produced by Osaka Titanium Technologies Co., Ltd.) on a TiO ₂ basis, and ammonia A white slurry liquid having a pH of 9.5 was prepared by mixing 4.41 kg of 15% by weight ammonia water (manufactured by Ube Industries). 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, 4.40 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 (Asahi Kasei Co., Ltd., ACV-3010), and the titanium-based fine particles having a solid content of 10% by weight ( Hereinafter, 9.90 kg of an aqueous dispersion sol containing “P-2”) was obtained.
The solid matter contained in the mixed aqueous solution thus obtained was measured by the above method. As a result, titanium-based fine particles (primary particles) having a rutile crystal structure and composed of a composite oxide containing titanium, tin and silicon were obtained. )Met. Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, TiO ₂ 82.0 wt%, SnO ₂ 10.2 wt%, SiO ₂ 6. 0 was wt% and K ₂ O1.8% by weight. The pH of the mixed aqueous solution was 9.2.

Further, the water-dispersed sol containing the titanium-based fine particles is transparent milky white, the average particle size of the titanium-based fine particles contained in the water-dispersed sol is 31 nm, and coarse particles having a particle size of 100 nm or more. The distribution frequency was 0%. Furthermore, the specific surface area of the obtained titanium-based fine particles was 138 m ² / g.
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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.544, 1.584, 1.630, 1.683, 1 .743 and 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 film refractive index Nav calculated from the Maxwell-Garnet formula is 1.7. The refractive index of the particle showing × 10 ⁻⁴ and showing its minimum value was 2.35. Thereby, it could be considered that the refractive index of the titanium-based fine particles was 2.35.

(2) Preparation of water-dispersed sol containing titanium-based fine particles surface-coated with silica-based oxide Next, the water-dispersed sol of titanium-based fine particles P-1 used in Example 1 (solid content) (10.0 wt%) In place of 9.90 kg, except that 9.90 kg of the aqueous dispersion sol (solid content 10.0 wt%) of titanium-based fine particles P-2 obtained above was used. Under the conditions described in Example 1, a water-dispersed sol (hereinafter referred to simply as “surface-coated titanium-based fine particles”) coated with silica-based oxide (hereinafter referred to simply as “surface-coated titanium-based fine particles”) has a solid content of 20. 088%) was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.88 kg of water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle diameter of about 2 μm as a granular dried product. 1.18 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, 1.18 kg of the surface-coated titanium-based fine particle aggregate obtained above was fired under the conditions described in Example 1 to obtain 1.10 kg of a fired product of the surface-coated titanium-based fine particle aggregate. .
The surface-coated titanium fine particles obtained by firing in this way had a specific surface area of 192 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile crystal structure, and the X-ray diffraction crystallite diameter was 8.9 nm. Furthermore, the interplanar spacing of (310) crystal planes determined by X-ray diffraction was 0.14522 nm, and the interplanar spacing of (301) crystal planes was 0.1357 nm. Further, 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, 0.21 kg of the fired product of the obtained surface-coated titanium-based fine particle aggregate was subjected to a wet pulverizer and pulverized under the conditions described in Example 1, and the quartz beads used here were separated and removed. After that, methanol was further added and stirred to obtain about 1.55 kg of a methanol dispersion sol having a solid content of 11% by weight.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle size of the metal oxide fine particles contained in the methanol-dispersed sol was 41 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 8.0%.

Next, the methanol-dispersed sol containing the metal oxide fine particles is washed with methanol under the conditions described in Example 1 and then treated with a cation exchange resin, and further subjected to a centrifuge to obtain a particle size of 100 nm or more. The coarse particles having the above were classified and removed to obtain 1.70 kg of a methanol dispersion sol containing the metal oxide fine particles having a solid content of 6.7% by weight.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol-dispersed sol having a solid content of 20% by weight, That is, 0.56 kg of methanol-dispersed sol containing metal oxide fine particles (hereinafter referred to as “DP-2”) obtained by firing and pulverizing the surface-coated titanium-based fine particle aggregate and further classifying and removing coarse particles was obtained. .

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.4 cm ⁻¹ . The average particle size of the metal oxide fine particles contained in the methanol-dispersed sol was 32 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 0%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface) was 192 m ² / g.
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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.523, 1.551, 1.579, 1.619, 1 661, 1.685. 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 1.3. The refractive index of the particle showing × 10 ⁻⁵ and its 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 2.04.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[Example 3]
(1) Preparation of aqueous zirconate peroxide solution 15.79 kg of zirconium oxychloride aqueous solution containing 2.0% by weight of zirconium oxychloride (manufactured by Taiyo Mining Co., Ltd.) in terms of ZrO ₂ , and 15% of ammonia. Aqueous ammonia containing 0.0 wt% was gradually added with stirring to obtain a slurry solution having a pH of 8.5 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, 3.15 kg of pure water was added to 0.35 kg of the cake, and 0.21 kg of 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, 0.70 kg 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, 2.59 kg of pure water was added to obtain 7.00 kg of an aqueous zirconate peroxide solution containing 0.5 wt% of zirconate peroxide in terms of ZrO ₂ on a conversion basis. The pH of this aqueous zirconate peroxide solution was 12.0.

(2) Preparation of silicic acid solution On the other hand, after diluting 0.54 kg of commercially available water glass (manufactured by AGC S-Tech Co., Ltd.) with pure water, a cation exchange resin (manufactured by Mitsubishi Chemical Corporation). Was used to obtain 5.25 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.

(3) Preparation of methanol-dispersed sol containing titanium-based fine particles surface-coated with a complex oxide containing zirconium and silicon Water-dispersed titanium-based fine particles P-1 prepared in the same manner as in Example 1 After adding 79.57 kg of pure water to 7.00 kg of sol (the solid content is 10.0 wt%), stirring and heating to 90 ° C., the weight of the titanium-based fine particles is represented by C, and When the weight of the coating layer is represented by S, this water-dispersed sol is 0.5% by weight peroxidation on a ZrO ₂ basis so that the weight ratio (S / C) is 20/100 on an oxide basis. 7.00 kg of an aqueous zirconic acid solution and 5.25 kg of an aqueous 2.0 wt% silicic acid solution based on SiO ₂ were gradually added. After the addition was completed, the mixture was aged with stirring for 1 hour while maintaining the temperature at 90 ° C.
Subsequently, this liquid mixture was put into the autoclave (The pressure | voltage resistant glass industry Co., Ltd. make, 120L), and it heat-processed at the temperature of 165 degreeC for 18 hours.

Next, after cooling the obtained mixed solution to room temperature, 0.38 kg of cation exchange resin (Mitsubishi Chemical Corporation) was mixed and stirred for 30 minutes. Next, the cation exchange resin is separated and removed using a stainless steel filter having an opening of 44 μm, and then concentrated using an ultrafiltration membrane (Asahi Kasei Co., Ltd., SIP-1013) to obtain a solid content. A 20% by weight aqueous dispersion sol was prepared. Thus, 4.12 kg of an aqueous dispersion sol containing surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) obtained by coating the surface of the titanium-based fine particles with a composite oxide containing zirconium and silicon. Got.
The refractive index of the composite oxide containing zirconium and silicon formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) is 1.54, which is 0.88 lower than the refractive index of the titanium-based fine particles. Met.

Next, 4.12 kg of the water-dispersed sol containing the surface-coated titanium-based 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, 0.82 kg of a surface-coated titanium-based fine particle aggregate (tertiary particle) having an average particle diameter of about 2 μm as a granular dried product was obtained.
Next, 0.82 kg of the surface-coated titanium-based fine particle aggregate obtained above was baked at a temperature of 500 ° C. for 1 hour in an air atmosphere, and 0.77 kg of the fired product of the surface-coated titanium-based fine particle aggregate. Got.
The surface-coated titanium fine particles obtained by firing in this manner had a specific surface area of 161 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile type crystal structure, and the X-ray diffraction crystallite diameter was 9.6 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the surface-coated titanium-based fine particle aggregate obtained was 0.53 kg of methanol (produced by Hayashi Junyaku Co., Ltd.), L-(+)-tartaric acid (produced by Kanto Chemical Co., Ltd.) The mixture was dispersed in a mixed solution consisting of 45.3 g and diisopropylamine (Tokyo Chemical Industry Co., Ltd.) 29.7. Next, 1.00 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 solution, and this was mixed with a wet pulverizer (Kampe Co., Ltd.). The baked product of the surface-coated titanium-based fine particle aggregate was subjected to pulverization treatment for 180 minutes using a batch type tabletop sand mill). Thereafter, the quartz beads were separated and removed using a stainless steel filter having an opening of 44 μm, and methanol was further added and stirred to obtain about 1.55 kg of a methanol-dispersed sol having a solid content of 11% by weight.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle size of the metal oxide fine particles contained in the methanol-dispersed sol was 43 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 11.2%.

Next, the methanol-dispersed sol containing the metal oxide fine particles was washed with 1.38 kg of methanol added from the outside using an ultrafiltration membrane (SIP-1013, manufactured by Asahi Kasei Co., Ltd.).
0.35 kg of an anion exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with 1.55 kg of the methanol-dispersed sol containing the metal oxide fine particles thus obtained and stirred for 30 minutes. Next, the anion exchange resin was separated and removed using a stainless steel filter having an opening of 44 μm, and this methanol dispersion sol was subjected to a centrifuge (CR-21G manufactured by Hitachi Koki Co., Ltd.). Processing was performed at a speed of 000 rpm for 1 hour, and coarse particles having a particle diameter of 100 nm or more were classified and removed. As a result, 1.70 kg of a methanol-dispersed sol containing the metal oxide fine particles having a solid content of 6.5% by weight was obtained.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles (solid content: 6.5% by weight) was concentrated with an ultrafiltration membrane device (Asahi Kasei Co., Ltd., SIP-2013) to obtain a solid Methanol-dispersed sol having a content of 20% by weight, that is, the surface-coated titanium-based fine particle aggregate is fired and pulverized, and coarse particles are classified and removed (hereinafter referred to as “DP-3”). ) Containing 0.55 kg of methanol-dispersed sol.

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.5 cm ⁻¹ . The average particle size of the metal oxide fine particles contained in the methanol-dispersed sol was 36 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 0%. The specific surface area of the metal oxide fine particles (that is, titanium-based fine particles having a composite oxide coating layer containing zirconium and silicon on the surface) was 161 m ² / g.
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 8.7% by weight, SiO ₂ 15 based on the oxide conversion standard of each metal component. .2 wt%, it was ZrO ₂ 4.9 wt% and K ₂ O0.3% by weight. The specific gravity of the metal oxide fine particles determined from the metal content was 3.88.

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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.530, 1.566, 1.605, 1.650, 1 .702, 1.730. 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 4.4. The refractive index of the particle showing × 10 ⁻⁶ and its minimum value was 2.13. Accordingly, the refractive index of the metal oxide fine particles could be regarded as 2.13. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.13.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[Example 4]
Preparation of methanol-dispersed sol containing titanium-based fine particles surface-coated with silica-based oxide Water-dispersed sol of titanium-based fine particles P-1 prepared by the same method as in Example 1 (with a solid content of 10.0 wt%), 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 10 / Under the conditions described in Example 1, except that 0.48 kg of normal ethyl silicate (manufactured by Tama Chemical Co., Ltd.) containing 28% by weight of the silicon component in terms of SiO ₂ was added so as to be 100. 5.34 kg of an aqueous dispersion sol (solid content: 20.0% by weight) containing surface-coated titanium-based fine particles coated with oxide (hereinafter simply referred to as “surface-coated titanium-based fine particles”) was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.34 kg of the water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle size of about 2 μm as a granular dried product. 1.07 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, 1.07 kg of the surface-coated titanium-based fine particle aggregate obtained above was fired at 700 ° C. for 1 hour in an air atmosphere, and 1.00 kg of a fired product of the surface-coated titanium-based fine particle aggregate. Got.
The surface-coated titanium fine particles obtained by firing in this way had a specific surface area of 109 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile-type crystal structure, and the X-ray diffraction crystallite diameter was 13.4 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the obtained surface-coated titanium-based fine particle aggregate was subjected to a wet pulverizer and pulverized under the conditions described in Example 1, and the quartz beads used here were separated and removed. After that, methanol was further added and stirred to obtain about 1.55 kg of a methanol dispersion sol having a solid content of 11% by weight.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle diameter of the metal oxide fine particles contained in the methanol-dispersed sol was 47 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 16.3%.

Next, the methanol-dispersed sol containing the metal oxide fine particles is washed with methanol under the conditions described in Example 1 and then treated with a cation exchange resin, and further subjected to a centrifuge to obtain a particle size of 100 nm or more. The coarse particles having the above were classified and removed to obtain 1.70 kg of a methanol dispersion sol containing the metal oxide fine particles having a solid content of 6.8% by weight.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol-dispersed sol having a solid content of 20% by weight, That is, 0.57 kg of methanol dispersion sol containing metal oxide fine particles (hereinafter referred to as “DP-4”) obtained by firing and pulverizing the surface-coated titanium-based fine particle aggregate and further classifying and removing coarse particles was obtained. .

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white, and its turbidity was 5.6 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the methanol-dispersed sol was 42 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface) was 109 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, TiO ₂ 80.0% by weight, SnO ₂ 10.0% by weight, SiO ₂ 9 in terms of oxide conversion standards of each metal component. .8 was wt% and K ₂ O0.2% by weight. The specific gravity of the metal oxide fine particles determined from the metal content was 4.09.

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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 55 wt%, 1.534, 1.565, 1.614, 1.668, 1 .724, 1.752. 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 7.0. The refractive index of the particle showing × 10 ⁻⁵ and its 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 2.24.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[Example 5]
Preparation of PGM-dispersed sol containing titanium-based fine particles coated with silica-based oxide Water-dispersed sol of titanium-based fine particles P-1 prepared by the same method as in Example 1 (with a solid content of 10) 0.0 wt%) and water containing surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) coated with a silica-based oxide under the conditions described in Example 1. Dispersed sol (solid content 20.0% by weight) 5.82 kg was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.82 kg of water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle diameter of about 2 μm as a granular dried product. 1.16 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, 1.16 kg of the surface-coated titanium-based fine particle aggregate obtained above was fired under the conditions described in Example 1 to obtain 1.09 kg of a fired product of the surface-coated titanium-based fine particle aggregate. .
The surface-coated titanium-based fine particles thus obtained had a specific surface area of 171 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile type crystal structure, and the X-ray diffraction crystallite diameter was 9.6 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the obtained surface-coated titanium-based fine particle aggregate was mixed with 0.53 kg of propylene glycol monomethyl ether (PGM, manufactured by Dow Chemical Co., Ltd.), L-(+)-tartaric acid (Kanto Chemical) (Distributed) 45.3 g and diisopropylamine (Tokyo Chemical Industry Co., Ltd.) 29.7 g. Next, 1.00 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 the mixed solution, and the resulting mixture was mixed with a wet pulverizer (Kampe Co., Ltd. batch). The baked product of the surface-coated titanium-based fine particle aggregate was subjected to pulverization treatment for 180 minutes by using a tabletop sand mill. Thereafter, as in Example 1, after separating and removing the quartz beads used here, propylene glycol monomethyl ether (PGM) was further added and stirred to disperse the PGM having a solid content of 11% by weight. About 1.55 kg of sol was obtained.
The PGM dispersion sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle diameter of the metal oxide fine particles contained in this PGM dispersion sol was 45 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 12.1%.

Next, the PGM-dispersed sol containing the metal oxide fine particles is washed with PGM under the conditions described in Example 1, then treated with a cation exchange resin, and further subjected to a centrifuge to obtain a particle size of 100 nm or more. The coarse particles having the above were classified and removed to obtain 1.70 kg of a PGM dispersion sol containing the metal oxide fine particles having a solid content of 6.5% by weight.
Next, 1.70 kg of PGM-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a PGM-dispersed sol having a solid content of 20% by weight, That is, the surface-coated titanium-based fine particle aggregate was fired and pulverized, and 0.55 kg of PGM dispersion sol containing metal oxide fine particles (hereinafter referred to as “DP-5”) obtained by classifying and removing coarse particles was obtained. .

The PGM-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.6 cm ⁻¹ . Moreover, the average particle diameter of the silica surface-modified titanium-based fine particles contained in the PGM-dispersed sol was 37 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface) was 171 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 70.8% by weight of TiO ₂ , 8.8% by weight of SnO ₂ , SiO ₂ 20 based on the oxide conversion standard 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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, and 55% by weight, 1.530, 1.566, 1.604, 1.650, 1 .702, 1.730. Furthermore, 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 9.4. The refractive index of the particles having × 10 ⁻⁶ and 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 1.

[Example 6]
Preparation of methanol-dispersed sol containing titanium-based fine particles coated with silica-based oxide Water-dispersed sol of titanium-based fine particles P-1 prepared by the same method as in Example 1 (with a solid content of 10) 0.0 wt%) and water containing surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) coated with a silica-based oxide under the conditions described in Example 1. Dispersed sol (solid content 20.0% by weight) 5.82 kg was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.82 kg of water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle diameter of about 2 μm as a granular dried product. 1.16 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, 1.16 kg of the surface-coated titanium-based fine particle aggregate obtained above was fired under the conditions described in Example 1 to obtain 1.09 kg of a fired product of the surface-coated titanium-based fine particle aggregate. .
The surface-coated titanium-based fine particles thus obtained had a specific surface area of 168 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile-type crystal structure, and the X-ray diffraction crystallite diameter was 9.7 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the surface-coated titanium-based fine particle aggregate obtained was 0.53 kg of methanol (produced by Hayashi Junyaku Co., Ltd.), L-(+)-tartaric acid (produced by Kanto Chemical Co., Ltd.) The mixture was dispersed in a mixed liquid consisting of 21.0 g and 29.7 g of diisopropylamine (manufactured by Tokyo Chemical Industry Co., Ltd.). Next, 1.00 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 the mixed solution, and the resulting mixture was mixed with a wet pulverizer (Kampe Co., Ltd. batch). The baked product of the surface-coated titanium-based fine particle aggregate was subjected to pulverization treatment for 180 minutes by using a tabletop sand mill. Thereafter, as in Example 1, after separating and removing the quartz beads used here, methanol was further added and stirred to obtain about 1.55 kg of a methanol-dispersed sol having a solid content of 11 wt%. Obtained.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle diameter of the metal oxide fine particles contained in the methanol-dispersed sol was 45 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 12.2%.

Next, the methanol-dispersed sol containing the metal oxide fine particles is washed with methanol under the conditions described in Example 1 and then treated with a cation exchange resin, and further subjected to a centrifuge to obtain a particle size of 100 nm or more. Thus, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles having a solid content of 6.5% by weight was obtained.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol-dispersed sol having a solid content of 20% by weight, That is, 0.55 kg of methanol-dispersed sol containing metal oxide fine particles (hereinafter referred to as “DP-6”) obtained by firing and pulverizing the surface-coated titanium-based fine particle aggregate and further classifying and removing coarse particles was obtained. .

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.5 cm ⁻¹ . The average particle size of the silica surface-modified titanium-based fine particles contained in the methanol-dispersed sol was 39 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 0%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface thereof) was 170 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 70.8% by weight of TiO ₂ , 8.8% by weight of SnO ₂ , SiO ₂ 20 based on the oxide conversion standard 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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, and 55% by weight, 1.530, 1.566, 1.604, 1.650, 1 .702, 1.730. Furthermore, 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 9.4. The refractive index of the particles having × 10 ⁻⁶ and 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 1.

[Example 7]
Preparation of methanol-dispersed sol containing titanium-based fine particles coated with silica-based oxide Water-dispersed sol of titanium-based fine particles P-1 prepared by the same method as in Example 1 (with a solid content of 10) 0.0 wt%) and water containing surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) coated with a silica-based oxide under the conditions described in Example 1. Dispersed sol (solid content 20.0% by weight) 5.82 kg was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.82 kg of water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle diameter of about 2 μm as a granular dried product. 1.16 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, 1.16 kg of the surface-coated titanium-based fine particle aggregate obtained above was fired under the conditions described in Example 1 to obtain 1.09 kg of a fired product of the surface-coated titanium-based fine particle aggregate. .
The surface-coated titanium-based fine particles thus obtained had a specific surface area of 168 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile-type crystal structure, and the X-ray diffraction crystallite diameter was 9.7 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the surface-coated titanium-based fine particle aggregate obtained was 0.53 kg of methanol (produced by Hayashi Junyaku Co., Ltd.), L-(+)-tartaric acid (produced by Kanto Chemical Co., Ltd.) The mixture was dispersed in a mixed solution consisting of 45.3 g and 10.5 g of diisopropylamine (Tokyo Chemical Industry Co., Ltd.). Next, 1.00 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 the mixed solution, and the resulting mixture was mixed with a wet pulverizer (Kampe Co., Ltd. batch). The baked product of the surface-coated titanium-based fine particle aggregate was subjected to pulverization treatment for 180 minutes by using a tabletop sand mill. Thereafter, as in Example 1, after separating and removing the quartz beads used here, methanol was further added and stirred to obtain about 1.55 kg of a methanol-dispersed sol having a solid content of 11 wt%. Obtained.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle size of the metal oxide fine particles contained in the methanol-dispersed sol was 45 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 12.3%.

Next, the methanol-dispersed sol containing the metal oxide fine particles is washed with methanol under the conditions described in Example 1 and then treated with a cation exchange resin, and further subjected to a centrifuge to obtain a particle size of 100 nm or more. Thus, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles having a solid content of 6.5% by weight was obtained.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol-dispersed sol having a solid content of 20% by weight, That is, 0.55 kg of methanol-dispersed sol containing metal oxide fine particles (hereinafter referred to as “DP-7”) obtained by firing and pulverizing the surface-coated titanium-based fine particle aggregate and further classifying and removing coarse particles was obtained. .

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.5 cm ⁻¹ . Moreover, the average particle diameter of the silica surface-modified titanium-based fine particles contained in the methanol-dispersed sol was 40 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface thereof) was 170 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 70.8% by weight of TiO ₂ , 8.8% by weight of SnO ₂ , SiO ₂ 20 based on the oxide conversion standard 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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, and 55% by weight, 1.530, 1.566, 1.604, 1.650, 1 .702, 1.730. Furthermore, 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 9.4. The refractive index of the particles having × 10 ⁻⁶ and 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 1.

[Example 8]
Preparation of methanol-dispersed sol containing titanium-based fine particles coated with silica-based oxide Water-dispersed sol of titanium-based fine particles P-1 prepared by the same method as in Example 1 (with a solid content of 10) 0.0 wt%) and water containing surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) coated with a silica-based oxide under the conditions described in Example 1. Dispersed sol (solid content 20.0% by weight) 5.82 kg was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.82 kg of water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle diameter of about 2 μm as a granular dried product. 1.16 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, 1.16 kg of the surface-coated titanium-based fine particle aggregate obtained above was fired under the conditions described in Example 1 to obtain 1.09 kg of a fired product of the surface-coated titanium-based fine particle aggregate. .
The surface-coated titanium-based fine particles thus obtained had a specific surface area of 168 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile-type crystal structure, and the X-ray diffraction crystallite diameter was 9.7 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the surface-coated titanium-based fine particle aggregate obtained was 0.53 kg of methanol (produced by Hayashi Junyaku Co., Ltd.) and 45.3 g of DL-malic acid (produced by Kanto Chemical Co., Inc.). And 29.7 g of diisopropylamine (manufactured by Tokyo Chemical Industry Co., Ltd.). Next, 1.00 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 the mixed solution, and the resulting mixture was mixed with a wet pulverizer (Kampe Co., Ltd. batch). The baked product of the surface-coated titanium-based fine particle aggregate was subjected to pulverization treatment for 180 minutes by using a tabletop sand mill. Thereafter, as in Example 1, after separating and removing the quartz beads used here, methanol was further added and stirred to obtain about 1.55 kg of a methanol-dispersed sol having a solid content of 11 wt%. Obtained.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle size of the metal oxide fine particles contained in the methanol-dispersed sol was 45 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 12.3%.

Next, the methanol-dispersed sol containing the metal oxide fine particles is washed with methanol under the conditions described in Example 1 and then treated with a cation exchange resin, and further subjected to a centrifuge to obtain a particle size of 100 nm or more. Thus, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles having a solid content of 6.5% by weight was obtained.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol-dispersed sol having a solid content of 20% by weight, That is, 0.55 kg of methanol dispersion sol containing metal oxide fine particles (hereinafter referred to as “DP-8”) obtained by firing and pulverizing the surface-coated titanium-based fine particle aggregate and further classifying and removing coarse particles was obtained. .

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.5 cm ⁻¹ . Moreover, the average particle diameter of the silica surface-modified titanium-based fine particles contained in the methanol-dispersed sol was 36 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface thereof) was 170 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 70.8% by weight of TiO ₂ , 8.8% by weight of SnO ₂ , SiO ₂ 20 based on the oxide conversion standard 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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, and 55% by weight, 1.530, 1.566, 1.604, 1.650, 1 .702, 1.730. Furthermore, 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 9.4. The refractive index of the particles having × 10 ⁻⁶ and 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 1.

[Example 9]
Preparation of methanol-dispersed sol containing titanium-based fine particles coated with silica-based oxide Water-dispersed sol of titanium-based fine particles P-1 prepared by the same method as in Example 1 (with a solid content of 10) 0.0 wt%) and water containing surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) coated with a silica-based oxide under the conditions described in Example 1. Dispersed sol (solid content 20.0% by weight) 5.82 kg was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.82 kg of water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle diameter of about 2 μm as a granular dried product. 1.16 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, 1.16 kg of the surface-coated titanium-based fine particle aggregate obtained above was fired under the conditions described in Example 1 to obtain 1.09 kg of a fired product of the surface-coated titanium-based fine particle aggregate. .
The surface-coated titanium-based fine particles thus obtained had a specific surface area of 168 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile-type crystal structure, and the X-ray diffraction crystallite diameter was 9.7 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the surface-coated titanium-based fine particle aggregate obtained was 0.53 kg of methanol (produced by Hayashi Junyaku Co., Ltd.), L-(+)-tartaric acid (produced by Kanto Chemical Co., Ltd.) The mixture was dispersed in a mixed solution consisting of 45.3 g and 29.7 g of diisobutylamine (manufactured by Tokyo Chemical Industry Co., Ltd.). Next, 1.00 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 the mixed solution, and the resulting mixture was mixed with a wet pulverizer (Kampe Co., Ltd. batch). The baked product of the surface-coated titanium-based fine particle aggregate was subjected to pulverization treatment for 180 minutes by using a tabletop sand mill. Thereafter, as in Example 1, after separating and removing the quartz beads used here, methanol was further added and stirred to obtain about 1.55 kg of a methanol-dispersed sol having a solid content of 11 wt%. Obtained.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle diameter of the metal oxide fine particles contained in the methanol-dispersed sol was 45 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 12.4%.

Next, the methanol-dispersed sol containing the metal oxide fine particles is washed with methanol under the conditions described in Example 1 and then treated with a cation exchange resin, and further subjected to a centrifuge to obtain a particle size of 100 nm or more. Thus, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles having a solid content of 6.5% by weight was obtained.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol-dispersed sol having a solid content of 20% by weight, That is, 0.55 kg of methanol-dispersed sol containing metal oxide fine particles (hereinafter referred to as “DP-9”) obtained by firing and pulverizing the surface-coated titanium-based fine particle aggregate and further classifying and removing coarse particles was obtained. .

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 5.5 cm ⁻¹ . Moreover, the average particle diameter of the silica surface-modified titanium-based fine particles contained in the methanol-dispersed sol was 36 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 0%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface thereof) was 170 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 70.8% by weight of TiO ₂ , 8.8% by weight of SnO ₂ , SiO ₂ 20 based on the oxide conversion standard 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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, and 55% by weight, 1.530, 1.566, 1.604, 1.650, 1 .702, 1.730. Furthermore, 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 9.4. The refractive index of the particles having × 10 ⁻⁶ and 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 1.

[Comparative Example 1]
Preparation of methanol-dispersed sol containing titanium-based fine particles surface-coated with silica-based oxide Water-dispersed sol of titanium-based fine particles P-1 prepared by the same method as in Example 1 (with a solid content of 10.0 wt%) and surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) coated with a silica-based oxide under the conditions described in Example 1. 5.82 kg of an aqueous dispersion sol (solid content 20.0 wt%) was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.82 kg of water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle diameter of about 2 μm as a granular dried product. 1.16 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, unlike the case of Example 1, the surface-coated titanium-based fine particle aggregate obtained above was not fired.
The surface-coated titanium-based fine particles thus obtained had a specific surface area of 230 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile type crystal structure, and the X-ray diffraction crystallite diameter was 7.1 nm. Furthermore, 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. Further, 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, 0.21 kg of the obtained surface-coated titanium-based fine particle aggregate (dried material) was subjected to a wet pulverizer and pulverized under the conditions described in Example 1, and the quartz beads used here were separated and separated. After removal, methanol was further added and stirred to obtain about 1.49 kg of methanol-dispersed sol having a solid content of 11% by weight.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle size of the metal oxide fine particles contained in the methanol-dispersed sol was 141 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 83.6%.

Next, the methanol-dispersed sol containing the metal oxide fine particles is washed with methanol under the conditions described in Example 1 and then treated with a cation exchange resin, and further subjected to a centrifuge to obtain a particle size of 100 nm or more. The coarse particles having the above were classified and removed to obtain 1.70 kg of a methanol dispersion sol containing the metal oxide fine particles having a solid content of 5.8% by weight.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol-dispersed sol having a solid content of 20% by weight, That is, 0.49 kg of methanol dispersion sol containing metal oxide fine particles (hereinafter referred to as “RDP-1”) obtained by pulverizing the surface-coated titanium-based fine particle aggregate (dried product) and further classifying and removing coarse particles was obtained. .

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white, and its turbidity was 10.8 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the methanol-dispersed sol was 103 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 68.2%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface) was 230 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 70.7% by weight of TiO ₂ , 8.9% by weight of SnO ₂ , SiO ₂ 20 based on the oxide conversion standard of each metal component. 0.2% by weight and 0.2% by weight of K ₂ O. The specific gravity of the metal oxide fine particles determined from the metal content was 3.68.

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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, and 55% by weight, 1.530, 1.558, 1.582, 1.624, 1 667, 1.691. 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 6.6. The refractive index of the particles showing × 10 ⁻⁵ and the minimum value thereof was 2.02. Thereby, the refractive index of the metal oxide fine particles was considered to be 2.02. Incidentally, the refractive index of the metal oxide fine particles measured by the refractive index measurement method B (standard solution method) was 2.02.
Among the above measurement results, main data related to the present invention are shown in Table 1.

[Comparative Example 2]
Preparation of methanol-dispersed sol containing titanium-based fine particles surface-coated with silica-based oxide Water-dispersed sol of titanium-based fine particles P-1 prepared by the same method as in Example 1 (with a solid content of 10.0 wt%) and surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) coated with a silica-based oxide under the conditions described in Example 1. 5.82 kg of an aqueous dispersion sol (solid content 20.0 wt%) was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.82 kg of water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle diameter of about 2 μm as a granular dried product. 1.16 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, 1.16 kg of the surface-coated titanium-based fine particle aggregate obtained above was calcined for 1 hour at a temperature of 850 ° C. in an air atmosphere instead of the calcining temperature of 500 ° C. employed in Example 1. 1.09 kg of a fired product of the surface-coated titanium-based fine particle aggregate was obtained.
The surface-coated titanium-based fine particles thus obtained had a specific surface area of 58 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile-type crystal structure and an X-ray diffraction crystallite diameter of 28.0 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the obtained surface-coated titanium-based fine particle aggregate was subjected to a wet pulverizer and pulverized under the conditions described in Example 1, and the quartz beads used here were separated and removed. Thereafter, methanol was further added and stirred to obtain about 1.49 kg of a methanol-dispersed sol having a solid content of 11% by weight.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle size of the metal oxide fine particles contained in this water-dispersed sol was 139 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 86.2%.

Next, the methanol-dispersed sol containing the metal oxide fine particles is washed with methanol under the conditions described in Example 1 and then treated with a cation exchange resin, and further subjected to a centrifuge to obtain a particle size of 100 nm or more. The coarse particles having the above were classified and removed to obtain 1.70 kg of a methanol dispersion sol containing the metal oxide fine particles having a solid content of 5.8% by weight.
Next, 1.70 kg of the aqueous methanol dispersion sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol dispersion sol having a solid content of 20% by weight. That is, 0.49 kg of methanol-dispersed sol containing metal oxide fine particles (hereinafter referred to as “RDP-2”) obtained by firing and pulverizing the surface-coated titanium-based fine particle aggregate and further classifying and removing coarse particles is obtained. It was.

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 11.9 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the methanol-dispersed sol was 105 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 70.6%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface) was 58 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 70.8% by weight of TiO ₂ , 8.8% by weight of SnO ₂ , SiO ₂ 20 based on the oxide conversion standard of each metal component. .1 was wt% and K ₂ O0.3% by weight. 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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.530, 1.562, 1.610, 1.664, 1 .722, 1.751. 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 film refractive index Nav calculated from the Maxwell-Garnet formula is 1.1. The refractive index of the particle showing × 10 ^-4 and showing the minimum value was 2.23. Thereby, the refractive index of the metal oxide fine particles could be regarded as 2.23. 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 1.

[Comparative Example 3]
Preparation of methanol-dispersed sol containing titanium-based fine particles coated with silica-based oxide Water-dispersed sol of titanium-based fine particles P-1 prepared by the same method as in Example 1 (with a solid content of 10) 0.0 wt%) and water containing surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) coated with a silica-based oxide under the conditions described in Example 1. Dispersed sol (solid content 20.0% by weight) 5.82 kg was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.82 kg of water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle diameter of about 2 μm as a granular dried product. 1.16 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, 1.16 kg of the surface-coated titanium-based fine particle aggregate obtained above was fired under the conditions described in Example 1 to obtain 1.09 kg of a fired product of the surface-coated titanium-based fine particle aggregate. .
The surface-coated titanium-based fine particles thus obtained had a specific surface area of 168 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile-type crystal structure, and the X-ray diffraction crystallite diameter was 9.7 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the obtained surface-coated titanium-based fine particle aggregate was subjected to a wet pulverizer, and pulverized for 60 minutes instead of the pulverization time of 180 minutes employed in Example 1 (however, other The conditions were the same as in Example 1.) Then, as in Example 1, after separating and removing the quartz beads used here, methanol was further added and stirred to obtain about 1.49 kg of a methanol-dispersed sol having a solid content of 11 wt%. Got.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle diameter of the metal oxide fine particles contained in the methanol-dispersed sol was 162 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 93.1%.

Next, the methanol-dispersed sol containing the metal oxide fine particles is washed with methanol under the conditions described in Example 1 and then treated with a cation exchange resin, and further subjected to a centrifuge to obtain a particle size of 100 nm or more. The coarse particles having the above were classified and removed to obtain 1.70 kg of a methanol dispersion sol containing the metal oxide fine particles having a solid content of 5.9% by weight.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol-dispersed sol having a solid content of 20% by weight, That is, 0.49 kg of methanol dispersion sol containing metal oxide fine particles (hereinafter referred to as “RDP-3”) obtained by firing and pulverizing the surface-coated titanium-based fine particle aggregate and further classifying and removing coarse particles was obtained. .

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was milky white, and its turbidity was 13.5 cm ⁻¹ . The silica surface-modified titanium-based fine particles contained in the methanol-dispersed sol had an average particle size of 102 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 77.3%. The specific surface area of the metal oxide fine particles (that is, titanium-based fine particles having a silica-based oxide coating layer on the surface) was 168 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 70.8% by weight of TiO ₂ , 8.8% by weight of SnO ₂ , SiO ₂ 20 based on the oxide conversion standard 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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, and 55% by weight, 1.530, 1.566, 1.604, 1.650, 1 .702, 1.730. 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 1.6. The refractive index of the particle showing × 10 ⁻⁵ and the minimum value thereof was 2.11. Thereby, it could be considered that the refractive index of the metal oxide fine particles was 2.11. 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 1.

[Comparative Example 4]
Preparation of methanol-dispersed sol containing titanium-based fine particles coated with silica-based oxide Water-dispersed sol of titanium-based fine particles P-1 prepared by the same method as in Example 1 (with a solid content of 10) 0.0 wt%) and water containing surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) coated with a silica-based oxide under the conditions described in Example 1. Dispersed sol (solid content 20.0% by weight) 5.82 kg was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.82 kg of water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle diameter of about 2 μm as a granular dried product. 1.16 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, 1.16 kg of the surface-coated titanium-based fine particle aggregate obtained above was fired under the conditions described in Example 1 to obtain 1.09 kg of a fired product of the surface-coated titanium-based fine particle aggregate. .
The surface-coated titanium-based fine particles thus obtained had a specific surface area of 166 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile type crystal structure, and the X-ray diffraction crystallite diameter was 9.8 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the obtained surface-coated titanium-based fine particle aggregate was subjected to a wet pulverizer and pulverized under the conditions described in Example 1, and the quartz beads used here were separated and removed. After that, methanol was further added and stirred to obtain about 1.55 kg of a methanol dispersion sol having a solid content of 11% by weight.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle diameter of the metal oxide fine particles contained in the methanol-dispersed sol was 45 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 12.0%.

Next, the methanol-dispersed sol containing the metal oxide fine particles was washed with methanol under the conditions described in Example 1 and then treated with a cation exchange resin to obtain a solid content of 9.8% by weight. 1.70 kg of methanol dispersion sol containing the metal oxide fine particles was obtained. However, the operation of classifying and removing coarse particles having a particle diameter of 100 nm or more by applying the methanol-dispersed sol to a centrifuge was not performed.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol-dispersed sol having a solid content of 20% by weight, That is, 0.83 kg of a methanol-dispersed sol containing metal oxide fine particles (hereinafter referred to as “RDP-4”) in which the surface-coated titanium-based fine particle aggregate was fired and pulverized but coarse particles were not classified and removed. Obtained.

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was milky white, and its turbidity was 10.3 cm ⁻¹ . The average particle diameter of the metal oxide fine particles contained in the methanol-dispersed sol was 66 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 31.0%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface) was 166 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, 70.6% by weight of TiO ₂ , 8.8% by weight of SnO ₂ , SiO ₂ 20 based on the oxide conversion standard of each metal component. .3 was wt% and K ₂ O0.3% by weight. 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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.530, 1.565, 1.603, 1.649, 1 .701, 1.729. 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 1.2. The refractive index of the particle showing × 10 ⁻⁵ and the minimum value thereof was 2.11. Thereby, it could be considered that the refractive index of the metal oxide fine particles was 2.11. 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 1.

[Comparative Example 5]
Preparation of methanol-dispersed sol containing titanium-based fine particles Water-dispersed sol of titanium-based fine particles P-2 prepared by the same method as in Example 2 (solid content is 10.0% by weight) 9.90 kg Was concentrated using an ultrafiltration device to obtain 4.90 kg of an aqueous dispersion sol having a solid content of 20.0% by weight, that is, here, a surface coating such as silica-based oxide was applied. An aqueous dispersion sol containing no titanium-based fine particles (hereinafter simply referred to as “titanium-based fine particles”) was prepared.
Next, 4.90 kg of the water-dispersed sol containing the titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface-coated titanium system having an average particle diameter of about 2 μm as a granular dried product. 0.98 kg of a fine particle aggregate was obtained.

Next, 0.98 kg of the titanium-based fine particle aggregate obtained above was fired under the conditions described in Example 1 to obtain 0.92 kg of a fired product of the titanium-based fine particle aggregate.
The titanium-based fine particles thus obtained had a specific surface area of 102 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile type crystal structure, and the X-ray diffraction crystallite diameter was 9.1 nm. Furthermore, 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 0.1358 nm. Further, 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, 0.21 kg of the fired product of the obtained titanium-based fine particle aggregate was subjected to a wet pulverizer and pulverized under the conditions described in Example 1, and the quartz beads used here were separated and removed. Further, methanol was added and stirred to obtain about 1.49 kg of a methanol-dispersed sol having a solid content of 11% by weight.
The methanol-dispersed sol containing metal oxide fine particles (titanium fine particles) obtained by pulverization in this manner was milky white. The average particle size of the metal oxide fine particles contained in the methanol-dispersed sol was 68 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 32.0%.

Next, the methanol-dispersed sol containing the metal oxide fine particles is washed with methanol under the conditions described in Example 1, then treated with a cation exchange resin, and further subjected to a centrifuge to give particles of 100 nm or more. The coarse particles having a diameter were classified and removed to obtain 1.70 kg of a methanol-dispersed sol containing the metal oxide fine particles having a solid content of 5.8% by weight.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol-dispersed sol having a solid content of 20% by weight, That is, the titanium-based fine particle aggregate was fired and pulverized, and 0.49 kg of methanol-dispersed sol containing metal oxide fine particles (hereinafter referred to as “RDP-5”) obtained by classifying and removing coarse particles was obtained.

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white, and its turbidity was 6.6 cm ⁻¹ . The average particle size of the metal oxide fine particles contained in the methanol-dispersed sol was 52 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 3.0%. The specific surface area of the metal oxide fine particles (that is, titanium-based fine particles not having a surface coating layer) was 102 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, 84.4% by weight of TiO ₂ , 9.9% by weight of SnO ₂ , SiO ₂ 5 based on the oxide conversion standard of each metal component. .3 was wt% and K ₂ O0.4% by weight. The specific gravity of the metal oxide 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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, 55% by weight, 1.544, 1.584, 1.630, 1.683, 1 .743 and 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 film refractive index Nav calculated from the Maxwell-Garnet formula is 1.7. The refractive index of the particle showing × 10 ⁻⁴ and showing its 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 1.

[Comparative Example 6]
Preparation of methanol-dispersed sol containing titanium-based fine particles coated with silica-based oxide Water-dispersed sol of titanium-based fine particles P-1 prepared by the same method as in Example 1 (with a solid content of 10) 0.0 wt%) and water containing surface-coated titanium-based fine particles (hereinafter simply referred to as “surface-coated titanium-based fine particles”) coated with a silica-based oxide under the conditions described in Example 1. Dispersed sol (solid content 20.0% by weight) 5.82 kg was obtained.
The refractive index of the silica-based oxide formed by forming the coating layer of the surface-coated titanium-based fine particles (secondary particles) was 1.45, 0.90 lower than the refractive index of the titanium-based fine particles.
Next, 5.82 kg of water-dispersed sol containing the surface-coated titanium-based fine particles is applied to a spray dryer and spray-dried under the conditions described in Example 1 to obtain a surface coating having an average particle diameter of about 2 μm as a granular dried product. 1.16 kg of titanium-based fine particle aggregate (tertiary particles) was obtained.

Next, 1.16 kg of the surface-coated titanium-based fine particle aggregate obtained above was fired under the conditions described in Example 1 to obtain 1.09 kg of a fired product of the surface-coated titanium-based fine particle aggregate. .
The surface-coated titanium-based fine particles thus obtained had a specific surface area of 168 m ² / g. Further, the titanium-based fine particles as the core particles had a rutile-type crystal structure, and the X-ray diffraction crystallite diameter was 9.7 nm. Furthermore, 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. Further, 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 .

Next, 0.21 kg of the fired product of the obtained surface-coated titanium-based fine particle aggregate was mixed with 0.53 kg of methanol (produced by Hayashi Junyaku Co., Ltd.) and L-(+)-tartaric acid (produced by Kanto Chemical Co., Inc.). ) 2.1 g and diisopropylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 1.1 g. Next, 1.00 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 the mixed solution, and the resulting mixture was mixed with a wet pulverizer (Kampe Co., Ltd. batch). The baked product of the surface-coated titanium-based fine particle aggregate was subjected to pulverization treatment for 180 minutes by using a tabletop sand mill. Thereafter, as in Example 1, after separating and removing the quartz beads used here, methanol was further added and stirred to obtain about 1.55 kg of a methanol-dispersed sol having a solid content of 11 wt%. Obtained.
The methanol-dispersed sol containing the metal oxide fine particles (quaternary particles) obtained by pulverization in this way was milky white. The average particle diameter of the metal oxide fine particles contained in the methanol-dispersed sol was 89 nm, and the distribution frequency of coarse particles having a particle diameter of 100 nm or more was 52.3%.

Next, the methanol-dispersed sol containing the metal oxide fine particles is washed with methanol under the conditions described in Example 1 and then treated with a cation exchange resin, and further subjected to a centrifuge to obtain a particle size of 100 nm or more. The coarse particles having the above were classified and removed to obtain 1.70 kg of a methanol dispersion sol containing the metal oxide fine particles having a solid content of 5.7% by weight.
Next, 1.70 kg of methanol-dispersed sol containing the metal oxide fine particles is subjected to an ultrafiltration membrane device under the conditions described in Example 1 and concentrated to obtain a methanol-dispersed sol having a solid content of 20% by weight, That is, 0.55 kg of methanol dispersion sol containing metal oxide fine particles (hereinafter referred to as “RDP-6”) obtained by firing and pulverizing the surface-coated titanium-based fine particle aggregate and further classifying and removing coarse particles was obtained. .

The methanol-dispersed sol containing the metal oxide fine particles thus obtained was transparent milky white and had a turbidity of 10.1 cm ⁻¹ . The silica surface-modified titanium-based fine particles contained in the methanol-dispersed sol had an average particle size of 64 nm, and the distribution frequency of coarse particles having a particle size of 100 nm or more was 12.0%. The specific surface area of the metal oxide fine particles (that is, titanium fine particles having a silica-based oxide coating layer on the surface thereof) was 170 m ² / g.
Furthermore, when the content of the metal component contained in the metal oxide fine particles was measured, it was 70.8% by weight of TiO ₂ , 8.8% by weight of SnO ₂ , SiO ₂ 20 based on the oxide conversion standard 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 the value of the particle contained in the coating composition for measurement. When the weight fraction m is 10%, 20%, 30%, 40%, 50%, and 55% by weight, 1.530, 1.566, 1.604, 1.650, 1 .702, 1.730. Furthermore, 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 9.4. The refractive index of the particles having × 10 ⁻⁶ and 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 1.

[Example 10 and Comparative Example 7]
Including metal oxide fine particles DP-1, DP-2, DP-3, DP-4, DP-6, DP-7, DP-8 or DP-9 prepared in the same manner as in Examples 1-9 PGM dispersion sol containing each methanol dispersion sol and DP-5, and metal oxide fine particles RDP-1, RDP-2, RDP-3, RDP-4, RDP- prepared by the same method as Comparative Examples 1-6 Each of the methanol dispersion sols containing 5 or RDP-6 is subjected to the above-mentioned “photocatalytic activity test of particles”, and the photocatalyst possessed by each metal oxide fine particle contained in these methanol dispersion sol or PGM dispersion sol The degree of activity was evaluated by the rate of change in fading of the sunset yellow dye used in the test. The evaluation results are shown in Table 2.
As a result, each metal oxide fine particle contained in the methanol-dispersed sol of the example or the PGM-dispersed sol has a considerably lower photocatalytic activity than each metal oxide fine particle contained in the methanol-dispersed sol of the comparative example. I understood. Therefore, the coating film obtained by preparing a coating liquid for forming a curable coating film using the methanol-dispersed sol or the PGM-dispersed sol according to the present invention as a starting material and applying it to a plastic substrate is weather resistant. It was recognized that it would be excellent.

[Example 11 and Comparative Example 8]
Including metal oxide fine particles DP-1, DP-2, DP-3, DP-4, DP-6, DP-7, DP-8 or DP-9 prepared in the same manner as in Examples 1-9 PGM dispersion sol containing each methanol dispersion sol and DP-5, and metal oxide fine particles RDP-1, RDP-2, RDP-3, RDP-4, RDP- prepared by the same method as Comparative Examples 1-6 Each of the methanol-dispersed sols containing 5 or RDP-6 is subjected to the above-mentioned “light resistance test of particles”, and blue discoloration (blue The degree of ing) was evaluated in relation to the irradiation time of ultraviolet rays used in the test. The evaluation results are shown in Table 3.
As a result, each metal oxide fine particle contained in the methanol-dispersed sol of the example or the PGM-dispersed sol is less likely to cause blue discoloration as compared with each metal oxide fine particle contained in the methanol-dispersed sol of the comparative example. I understood. Therefore, the coating film obtained by preparing a coating liquid for forming a curable coating film using the methanol-dispersed sol or PGM-dispersed sol according to the present invention as a starting material, and applying this to a plastic substrate or the like is light-resistant. It was recognized that it would be excellent.

[Example 12]
Preparation of PGM dispersion sol containing metal oxide fine particles Metal oxide fine particles DP-1, DP-2, DP-3, DP-4, DP- prepared in the same manner as in Examples 1-4 and 6-9 6, 0.47 kg of each methanol-dispersed sol containing DP-7, DP-8 or DP-9 was placed in a flask of a rotary evaporator (R-124 manufactured by BUCHI), and further propylene glycol monomethyl ether (PGM) 0 Place 39 kg into 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). Furthermore, by adjusting the content of propylene glycol monomethyl ether (PGM), the metal oxide fine particles DP-1, DP-2, DP-3, DP-4, DP-6 having a solid content of 20% by weight, 0.49 kg of PGM dispersion sol containing DP-7, DP-8 or DP-9 was prepared.
The appearance and turbidity of the PGM-dispersed sol containing the metal oxide fine particles thus obtained were as shown in Table 4.

[Example 13]
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 the container containing these hydrolyzed solutions, the refractive index of the methanol dispersion sol (solid content concentration: 20% by weight) prepared in Examples 1 to 4 and 6 to 9 is less than 2.20. For each methanol dispersion sol containing metal oxide fine particles DP-1, DP-2, DP-3, DP-6, DP-7, DP-8 or DP-9, 490 g and a refractive index of 2.20 or more, respectively. 450 g of methanol-dispersed sol containing fine metal oxide fine particles DP-4, 71 g of pure water, 3 g of Tris (2.4-pentanedionato) aluminum III (manufactured by Tokyo Chemical Industry Co., Ltd.) and a silicone-based leveling agent Surfactant (manufactured by Toray Dow Corning Co., Ltd., L-7001) 0.7 g is added, stirred at room temperature for a whole day and night, and a coating composition for forming a hard coat layer film as a coating composition for an optical substrate Products HX-1 (1), HX-2 (1), HX-3 (1), HX-4 (1), HX-6 (1), HX-7 (1), HX-8 (1) , HX-9 (1) was prepared respectively. These coating compositions contain metal oxide fine particles of DP-1, DP-2, DP-3, DP-4, DP-6, DP-7, DP-8, and DP-9, respectively. .

[Comparative Example 9]
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 the containers containing these hydrolyzed solutions, among the methanol-dispersed sols (solid content concentration: 20% by weight) prepared in Comparative Examples 1 to 6, metal oxide fine particles having a refractive index of less than 2.20. For each methanol dispersion sol containing RDP-1, RDP-3, RDP-4 or RDP-6, each methanol containing 490 g and metal oxide fine particles RDP-2 or RDP-5 having a refractive index of 2.20 or more Regarding the dispersion sol, 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 (Toray Dow Corning ( Co., Ltd., L-7001) 0.7 g was added and stirred at room temperature for a whole day and night to form a coating composition for forming a hard coat layer film as a coating composition for an optical substrate. HY-1 (1), HY-2 (1), HY-3 (1), HY-4 (1), HY-5 (1), and HY-6 (1) were prepared. These coating compositions contain metal oxide fine particles of RDP-1, RDP-2, RDP-3, RDP-4, RDP-5, and RDP-6, respectively.

[Example 14]
Preparation of coating solution for optical substrate (coating solution for forming hard coat layer film ) 110 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 41 g of a mixed solution were prepared, and 29 g of 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 the container containing these hydrolyzed solutions, the refractive index of the methanol dispersion sol (solid content concentration: 20% by weight) prepared in Examples 1 to 4 and 6 to 9 is less than 2.20. For each methanol dispersion sol containing metal oxide fine particles DP-1, DP-2, DP-3, DP-6, DP-7, DP-8 or DP-9, 490 g and a refractive index of 2.20 or more, respectively. 449 g of the methanol-dispersed sol containing the metal oxide fine particles DP-4, 3 g of Tris (2.4-pentanedionato) iron III (manufactured by Tokyo Chemical Industry Co., Ltd.), glycerol polyglycidyl ether (Nagase Chemical Industries ( Co., Ltd., Denacol EX-314, epoxy equivalent 145) 7 g and silicone surfactant as leveling agent (manufactured by Toray Dow Corning Co., Ltd., L-7001) 0.4 g, and stirred for a whole day at room temperature to form a coating composition HX-1 (2), HX-2 (2), HX-3 (2) for forming a hard coat layer film as a coating composition for an optical substrate , HX-4 (2), HX-6 (2), HX-7 (2), HX-8 (2) and HX-9 (2) were prepared, respectively. These coating compositions contain metal oxide fine particles of DP-1, DP-2, DP-3, DP-4, DP-6, DP-7, DP-8, and DP-9, respectively. .

[Comparative Example 10]
Preparation of coating solution for optical substrate (coating solution for forming hard coat layer film ) 110 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 41 g of a mixed solution were prepared, and 29 g of 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 the containers containing these hydrolyzed solutions, among the methanol-dispersed sols (solid content concentration: 20% by weight) prepared in Comparative Examples 1 to 6, metal oxide fine particles having a refractive index of less than 2.20. For each methanol dispersion sol containing RDP-1, RDP-3, RDP-4 or RDP-6, each methanol containing 490 g and metal oxide fine particles RDP-2 or RDP-5 having a refractive index of 2.20 or more For the dispersed sol, 449 g each, 3 g of Tris (2.4-pentanedionato) iron III (manufactured by Tokyo Chemical Industry Co., Ltd.), glycerol polyglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-314, 7 g of epoxy equivalent 145) and 0.4 g of a silicone surfactant (manufactured by Toray Dow Corning Co., Ltd., L-7001) as a leveling agent In addition, the coating composition HY-1 (2), HY-2 (2), HY-3 (2), HY for forming a hard coat layer film as a coating composition for an optical substrate is stirred at room temperature all day and night. -4 (2), HY-5 (2), and HY-6 (2) were prepared. These coating compositions contain metal oxide fine particles of RDP-1, RDP-2, RDP-3, RDP-4, RDP-5, and RDP-6, respectively.

[Example 15]
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 a metal having a refractive index of less than 2.20 among the methanol-dispersed sols (solid content concentration: 20% by weight) prepared in Examples 1 to 4 and 6 to 9 was used. Each methanol dispersion sol containing oxide fine particles DP-1, DP-2, DP-3, DP-6, DP-7, DP-8 or DP-9 is 395 g, and the surface has a refractive index of 2.20 or more. About the methanol dispersion sol containing the modified titanium-based fine particles DP-4, 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-6, PX-7, PX-8, and PX-9 were prepared, respectively. These coating compositions contain metal oxide fine particles of DP-1, DP-2, DP-3, DP-4, DP-6, DP-7, DP-8, and DP-9, respectively. .

[Comparative Example 11]
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 RDP having a refractive index of less than 2.20 among the methanol-dispersed sols (solid content concentration: 20% by weight) prepared in Comparative Examples 1-6. -1, RDP-3, RDP-4 or RDP-6 each methanol dispersion sol 430g, each methanol dispersion sol containing metal oxide fine particles RDP-2 or RDP-5 having a refractive index of 2.20 or more For each, 395 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) 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 and PY-6 were prepared respectively. These coating compositions contain metal oxide fine particles of RDP-1, RDP-2, RDP-3, RDP-4, RDP-5, and RDP-6, respectively.

[Preparation Example 1]
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 Example 13 and Comparative Example 9 was applied to the surface of the plastic lens substrate. A coating film was 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 2]
Preparation of plastic lens substrate for testing (2)
(1) Pretreatment of plastic lens substrate Pretreatment of the plastic lens substrate was performed under the same conditions as in Preparation Example 1.
(2) Formation of primer layer film The surface of the plastic lens substrate was coated with the coating composition (primer paint) for primer layer film formation obtained in Example 15 and Comparative Example 11, respectively. Formed. 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 (hard coat) obtained in Example 14 and Comparative Example 10 was formed on the surface of the plastic lens substrate formed with the primer layer film. Application paint) 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 Antireflection Film Layer A layer of an antireflection film was formed on the surface of the hard coat layer under the same conditions as in Preparation Example 1.

[Example 16]
Coating composition HX-1 (1), HX-2 (1), HX-3 (1), HX-4 (1), HX-6 (1) for forming a hard coat layer film obtained in Example 13 ), HX-7 (1), HX-8 (1) and HX-9 (1), a hard coat layer and an antireflection film layer are formed on the plastic lens substrate by the method shown in Preparation Example 1. Each was formed. Here, the plastic lens substrate “monomer name: MR-7” was used.
For each of the substrates HX-1, HX-2, HX-3, HX-4, HX-6, HX-7, HX-8 and HX-9 thus obtained, the above evaluation test method was used. The appearance (interference fringes), appearance (cloudiness), scratch resistance, adhesion, weather resistance and light resistance were tested and evaluated. The results are shown in Table 5.

[Comparative Example 12]
Coating composition HY-1 (1), HY-2 (1), HY-3 (1), HY-4 (1), HY-5 (1) for forming a hard coat layer film obtained in Comparative Example 9 ) And HY-6 (1), a hard coat layer and an antireflection film layer were formed on the plastic lens substrate by the method shown in Preparation Example 1, respectively. Here, the plastic lens substrate “monomer name: MR-7” was used.
For each of the substrates HY-1, HY-2, HY-3, HY-4, HY-5, and HY-6 thus obtained, the appearance (interference fringes), Appearance (cloudiness), scratch resistance, adhesion, weather resistance and light resistance were tested and evaluated. The results are shown in Table 6.
In Table 6 below, the reason why the scratch resistance was bad is that the coating composition for forming the hard coat layer film may be caused by aggregation or coarse particles of metal oxide fine particles contained in the coating composition for forming a hard coat layer. It is considered that the uniform dispersion of the metal oxide fine particles is hindered, resulting in the coating film surface becoming rough and non-uniform, and the formation of a dense portion in the coating film.

[Example 17]
Each of the coating compositions PX-1, PX-2, PX-3, PX-4, PX-6, PX-7, PX-8, and PX-9 for forming the primer layer film obtained in Example 15 was used. Using the coating composition for forming a hard coat layer film shown in Table 7 obtained in Example 14 and using the primer layer, the hard coat layer and the antireflection film on the plastic lens substrate by the method shown in Preparation Example 2 Each layer was formed.
Here, the plastic lens substrate “monomer name: MR-174” was used.
For each of the substrates PX-1, PX-2, PX-3, PX-4, PX-6, PX-7, PX-8 and PX-9 thus obtained, the above evaluation test method was used. The appearance (interference fringes), appearance (cloudiness), scratch resistance, adhesion, weather resistance and light resistance were tested and evaluated. The results are shown in Table 7. However, for light resistance, the test was canceled because the substrate used in the test itself had discoloration.

[Comparative Example 13]
Each of the coating compositions PY-1, PY-2, PY-3, PY-4, PY-5 and PY-6 for forming the primer layer film obtained in Comparative Example 11 was used, and obtained in Comparative Example 10. Using the resulting coating composition for forming a hard coat layer film shown in Table 8, a primer layer, a hard coat layer and an antireflection film layer were formed on a plastic lens substrate by the method shown in Preparation Example 2, respectively. Here, the plastic lens substrate “monomer name: MR-174” was used.
For each of the substrates PY-1, PY-2, PY-3, PY-4, PY-5, and PY-6 obtained in this way, the appearance (interference fringes), Appearance (cloudiness), scratch resistance, adhesion, weather resistance and light resistance were tested and evaluated. The results are shown in Table 8. However, for light resistance, the test was canceled because the substrate used in the test itself had discoloration.
In Table 8 below, the reason why the scratch resistance was bad is that, as in Comparative Example 12, the aggregates and coarse particles of metal oxide fine particles contained in the hard coat layer film-forming coating composition, etc. This is considered to be due to the fact that the uniform dispersion of the metal oxide fine particles in the coating composition is hindered, the surface of the coating film becomes rough and non-uniform, and further, a dense portion is formed in the coating film. It is done.

Claims (29)

A method for preparing an organic solvent-dispersed sol containing high-refractive-index metal oxide fine particles obtained by coating the surface of titanium-based fine particles containing titanium and tin and / or silicon with at least a silica-based oxide,
(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. A step of generating titanium-based fine particles (primary particles) made of a complex oxide;
(B) By mixing at least one silicon compound selected from silicon alkoxide and silicic acid into the mixed aqueous solution containing the titanium-based fine particles obtained in the step (a), and hydrolyzing the silicon compound. Obtaining surface-coated titanium-based fine particles (secondary particles) obtained by coating the surface of the titanium-based fine particles with a silica-based oxide;
(C) a step of obtaining a surface-coated titanium-based fine particle aggregate (tertiary particles) by drying and granulating the surface-coated titanium-based fine particles obtained in the step (b),
(D) A step of baking the surface-coated titanium-based particle aggregate obtained in the step (c) at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain a fired product of the surface-coated titanium-based particle aggregate. ,
(E) The fired product of the surface-coated titanium-based particle aggregate obtained in the step (d) is pulverized in the presence of an organic solvent, and the average particle size when measured by a dynamic light scattering method is 8 to 60 nm. A step of obtaining an organic solvent-dispersed sol obtained by further dispersing the metal oxide fine particles (quaternary particles) in an organic solvent, and (f) the organic solvent dispersion obtained in the step (e). A high refractive index metal oxide comprising a step 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 by subjecting the liquid to a wet classifier as necessary Preparation method of organic solvent dispersion sol of fine particles. A method for preparing an organic solvent-dispersed sol containing high refractive index metal oxide fine particles obtained by coating at least the surface of a composite oxide particle containing titanium and tin and / or silicon with a silica-based composite oxide,
(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. A step of generating titanium-based fine particles (primary particles) made of a complex oxide;
(B) In the mixed aqueous solution containing the titanium-based fine particles obtained in the step (a), at least one silicon compound selected from silicon alkoxide and silicic acid, zirconate peroxide, antimonate, and stannic acid A surface of the titanium-based fine particles is coated with a silica-based composite oxide by mixing at least one metal compound selected from a salt and an aluminate and hydrolyzing the silicon compound and the metal compound. A step of obtaining surface-coated titanium-based fine particles (secondary particles),
(C) a step of obtaining a surface-coated titanium-based fine particle aggregate (tertiary particles) by drying and granulating the surface-coated titanium-based fine particles obtained in the step (b),
(D) A step of baking the surface-coated titanium-based particle aggregate obtained in the step (c) at a temperature of 300 to 800 ° C. in an oxygen-containing atmosphere to obtain a fired product of the surface-coated titanium-based particle aggregate. ,
(E) The fired product of the surface-coated titanium-based particle aggregate obtained in the step (d) is pulverized in the presence of an organic solvent, and the average particle size when measured by a dynamic light scattering method is 8 to 60 nm. A step of obtaining an organic solvent-dispersed sol obtained by further dispersing the metal oxide fine particles (quaternary particles) in an organic solvent, and (f) the organic solvent dispersion obtained in the step (e). A high refractive index metal oxide comprising a step 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 by subjecting the liquid to a wet classifier as necessary Preparation method of organic solvent dispersion sol of fine particles.   3. The high refractive index metal oxide fine particle according to claim 1, 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 of organic solvent dispersion sol.   The high refractive index according to any one of claims 1 to 3, wherein the silicon alkoxide used in the step (b) is tetramethoxysilane or a condensate thereof, or tetraethoxysilane or a condensate thereof. A method for preparing an organic solvent-dispersed sol of metal oxide fine particles.   In the surface-coated titanium-based fine particles obtained in the step (b), 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 an oxide. 2. 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 1/100 to 50/100 on a conversion basis. The preparation method of the organic solvent dispersion | distribution sol of the high refractive index metal oxide fine particle in any one of -4.   The surface-coated titanium-based particle aggregate obtained in the step (c) is spray-dried by applying a mixed aqueous solution containing the surface-coated titanium-based fine particles to a spray dryer, thereby drying and granulating the surface-coated titanium-based fine particles. The method for preparing an organic solvent-dispersed sol of high refractive index metal oxide fine particles according to any one of claims 1 to 5, wherein   The organic solvent used in the step (e) is alcohol such as methanol, ethanol, butanol, propanol, isopropyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, etc. The organic compound of high refractive index metal oxide fine particles according to any one of claims 1 to 6, which is at least one organic compound selected from ketones such as ethers, methyl ethyl ketone, and γ-butyrolactone. Preparation method of solvent dispersion sol.   The high refractive index metal oxide fine particles according to any one of claims 1 to 7, further comprising a carboxylic acid compound and / or an amine compound in the organic solvent used in the step (e). Preparation method of organic solvent dispersion sol. 9. The method for preparing an organic solvent-dispersed sol of high refractive index metal oxide fine particles according to claim 8, wherein the carboxylic acid compound is at least one selected from tartaric acid, citric acid and malic acid. 9. The organic solvent-dispersed sol of high refractive index metal oxide fine particles according to claim 8, wherein the amine compound is at least one selected from diisopropylamine, diisobutylamine and tetramethylammonium hydroxide. Preparation method. By adding an anion exchange resin and / or a cation exchange resin to the organic solvent dispersion sol obtained in the step (f) and stirring, the ionized substance contained in the organic solvent dispersion sol is removed. The method for preparing an organic solvent-dispersed sol of high refractive index metal oxide fine particles according to any one of claims 1 to 10. An organic solvent-dispersed sol of metal oxide fine particles having a high refractive index obtained from the preparation method according to any one of claims 1 to 11,
(1) The titanium-based fine particles constituting the metal oxide fine particles are crystalline particles having a rutile-type crystal structure, and have an X-ray diffraction crystallite diameter of 7.5 to 14.0 nm. The refractive index is in the range of 2.2 to 2.7,
(2) The coating layer constituting the metal oxide fine particles has a refractive index lower by 0.2 or more than the refractive index of the titanium-based fine particles, and (3) the metal oxide fine particles have an average of 8 to 60 nm. It has a particle diameter and a specific surface area of 70 to 200 m ² / g, and its refractive index is in the range of 2.0 to 2.5. (4) The organic solvent-dispersed sol is 5 to 40% by weight. An organic solvent-dispersed sol of high refractive index metal oxide fine particles comprising the metal oxide fine particles and having a turbidity in the range of 0.1 to 11.0 cm ⁻¹ . 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, and (301) a crystal plane spacing d ^{2 of} 0.1. 13. The organic solvent-dispersed sol of high-refractive-index metal oxide fine particles according to claim 12, which is in the range of 1355 to 0.1370 nm. The titanium-based fine particles, 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⁾ is 9 / The organic solvent-dispersed sol of high-refractive-index metal oxide fine particles according to any one of claims 12 to 13, which is in a range of 100 to 20/100.   The organic solvent-dispersed sol of high refractive index metal oxide fine particles according to any one of claims 12 to 14, wherein the coating layer is a silica-based oxide substantially made of silicon dioxide.   The said coating layer is a silica type complex oxide containing silicon and at least 1 sort (s) of metal element chosen from zirconium, antimony, tin, and aluminum. Organic solvent dispersion sol of high refractive index metal oxide fine particles.   The metal oxide fine particles are characterized in that, in the particle size frequency distribution measured by a dynamic light scattering method, the distribution frequency of relatively coarse titanium-based fine particles having a particle size of 100 nm or more is 1% or less. The organic solvent dispersion sol of the high refractive index metal oxide fine particles according to any one of claims 12 to 16.   The organic solvent is an alcohol 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- 18. The organic solvent-dispersed sol of high refractive index metal oxide fine particles according to claim 12, which is at least one organic compound selected from ketones such as butyrolactone.   The coating composition containing the high refractive index metal oxide fine particle and binder component which are contained in the organic solvent dispersion | distribution sol in any one of Claims 12-18.   The coating composition according to claim 19, wherein the binder component is an organosilicon compound. The coating composition according to claim 19, wherein the organosilicon compound is an organosilicon compound represented by the following general formula (I) and / or a hydrolyzate thereof.
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.) The weight ratio (X / Y) of the organosilicon compound is 30 when the weight of the organosilicon compound converted to SiO ₂ is represented by X and the weight of the high refractive index metal oxide fine particles is represented by Y. The coating composition according to any one of claims 19 to 21, which is contained at a ratio of / 70 to 90/10.   The coating composition according to claim 20, wherein the binder component is a thermosetting organic resin or a thermoplastic organic resin.   The coating composition according to claim 23, wherein the thermosetting organic resin is at least one selected from a urethane resin, an epoxy resin, and a melamine resin.   24. The coating composition according to claim 23, wherein the thermoplastic organic resin is at least one selected from an acrylic resin, a urethane resin, and an ester resin.   When the weight of the resin compound is represented by A and the weight of the high refractive index metal oxide particles is represented by B in the thermosetting organic resin or the thermoplastic organic resin, the weight ratio (A / B) is 90. The coating composition according to any one of claims 23 to 25, which is contained at a ratio of / 10 to 30/70.   The coating composition according to any one of claims 19 to 26, wherein the coating composition is a coating composition for an optical substrate.   28. The coating composition according to claim 27, wherein the coating composition for an optical substrate is a coating composition for forming a hard coat layer film.   28. The coating composition according to claim 27, wherein the coating composition for an optical substrate is a coating composition for forming a primer layer film.