JP5432430B2 - Coating liquid for forming transparent film and substrate with transparent film - Google Patents

Description

  The present invention relates to a coating liquid for forming a transparent film and a substrate with a transparent film formed using the coating liquid. More specifically, the present invention has a high refractive index, high transmittance, no interference fringes, and scratch resistance. Transparent film with excellent adhesion, impact resistance, chemical resistance, weather resistance, light resistance, UV absorption performance, hot water resistance, flexibility and dyeability, and excellent adhesion to substrates such as glass and plastic The present invention relates to a coating solution for forming a film on the surface of a substrate and a substrate with a transparent coating formed using the coating solution.

Conventionally, various methods for forming a high refractive index hard coat film having a refractive index close to or equivalent to the refractive index of a substrate such as transparent plastic and glass have been proposed.
In this regard, in particular, diethylene glycol pis (allyl carbonate) resin lenses are superior in safety, easy processability, fashionability, etc. compared to glass lenses, and in recent years antireflection technology, hard coat technology, hard coat technology + With the development of anti-reflection technology, primer technology + hard coat technology + anti-reflection technology, etc., it has rapidly spread. However, since the refractive index of diethylene glycol bis (allyl carbonate) resin is 1.50, which is lower than that of a glass lens, the near vision lens has a drawback that its outer peripheral portion is thicker than that of a glass lens. For this reason, in the field of synthetic resin spectacle lenses, attempts to reduce the thickness by using a high refractive index resin material have been actively made. As such an attempt, Japanese Patent Application Laid-Open No. 59-133211 (Patent Document 1), Japanese Patent Application Laid-Open No. 63-46213 (Patent Document 2), Japanese Patent Application Laid-Open No. 2-270859 (Patent Document 3), etc. A high refractive index resin material having a refractive index of 1.60 or more has been proposed.

On the other hand, since the plastic spectacle lens has a drawback that it is easily damaged, a method of providing a silicon hard coat film on the surface of the plastic lens is generally performed. However, when the same method is applied to a high refractive index resin lens of 1.54 or more, interference fringes are generated due to a difference in refractive index between the resin lens and the coating film, which may cause poor appearance. In order to solve this problem, Japanese Patent Publication No. 61-54331 (Patent Document 4) and Japanese Patent Publication No. 63-37142 (Patent Document 5) disclose a coating solution for forming a silicon-based film (hereinafter referred to as a film forming film). The colloidal dispersion of silicon dioxide fine particles used in coating solutions (sometimes referred to as coating compositions) is made into a colloidal dispersion of Al, Ti, Zr, Sn, and Sb inorganic oxide fine particles having a high refractive index. A replacement technique is disclosed. JP-A-1-301517 (Patent Document 6) discloses a method for producing a composite sol of titanium dioxide and cerium dioxide, and JP-A-2-264902 (Patent Document 7). A composite inorganic oxide fine particle of Ti and Ce is disclosed, and JP-A-3-68901 (Patent Document 8) includes a coating composition containing fine particles obtained by treating a composite oxide of Ti, Ce and Si with an organosilicon compound. Things are disclosed.

In JP-A-5-2102 (Patent Document 9) and JP-A-7-76671 (Patent Document 10), a coating composition containing particles obtained by treating a composite inorganic oxide of Ti, Fe, and Si with an organosilicon compound. And cured films using the same are disclosed.

Further, the present applicant discloses in JP-A-8-48940 (Patent Document 11) a coating composition and a cured film containing fine particles obtained by treating a composite inorganic oxide of Ti, Si and Zr with an organosilicon compound. ing.

In recent years, the refractive index of plastic lenses (organic glass) has further increased. For example, plastic lenses having a refractive index of 1.71 to 1.74 are commercially available. However, since this high refractive index lens is inferior in dyeability and has poor impact resistance, it is necessary to provide a primer layer for improving impact resistance between the lens substrate and the hard coat layer. JP-A-6-82604 (Patent Document 12) and JP-A-6-138301 (Patent Document 13) disclose provision of a primer layer that does not cause optical interference.
JP 59-133211 JP-A-63-46213 Japanese Patent Laid-Open No. 2-270859 Japanese Patent Publication No. 61-54331 Japanese Patent Publication No. 63-37142 JP-A-1-301517 JP-A-2-264902 Japanese Patent Laid-Open No. 3-68901 JP-A-5-2102 JP 7-76671 A JP-A-8-48940 JP-A-6-82604 JP-A-6-138301

However, the coating compositions taught in Patent Document 4 and Patent Document 5 have the following problems.
For example, when a colloidal dispersion of Al, Zr, Sn, and Sb inorganic oxide fine particles is used as a coating composition for a high refractive index resin lens having a refractive index of 1.54 or more, it is applied and cured compared to a silicon-based coating composition. Although the degree of interference fringes can be improved later, when Al or Sb inorganic oxide fine particles are used, the refractive index as a coating film is limited, so that the refractive index is 1.6.
It was impossible to completely suppress interference fringes with respect to zero or more lens substrates. The reason for this is that although the inorganic oxide fine particles of Al and Sb have a refractive index of 1.60 or more,
In general, when used as a coating material, an organic silicon compound, an epoxy resin, or the like is mixed and used as a matrix component or a binder component, so that the filling rate is lowered and the refractive index as a coating becomes lower than that of the base lens.

  Further, when inorganic oxide fine particles of Zr and Sn are used, it is difficult to prepare a coating composition containing a large amount of such inorganic oxide fine particles because the dispersibility is unstable.

In contrast, the coating composition comprising a colloidal dispersion of inorganic oxide fine particles of Ti, in order to TiO ₂ itself has a higher refractive index than that of the inorganic oxide, formed coating 1.60 before and after Further, it has a higher refractive index than that, and therefore has the advantage that interference fringes can be suppressed and the range of the refractive index of the coating becomes wider. However, TiO ₂ is inferior in weather resistance and releases oxygen when irradiated with ultraviolet rays. Therefore, TiO ₂ is reduced and discolored to yellow, gray, blue, etc., and the released oxygen is an organosilicon compound in the coating formed from TiO ₂ . The organic component, the epoxy resin component, and the coating film on the surface of the resin base material deteriorated.

  For this reason, Patent Documents 7 and 8 disclose coating compositions containing fine particles in which titanium dioxide and cerium dioxide are combined in order to improve the weather resistance of titanium dioxide. In this respect, it is not always satisfactory, and since cerium dioxide has a yellowish color, the cured film obtained from these composite sols has a drawback that it is somewhat yellowish.

  In addition, the coating composition containing fine composite oxide particles composed of titanium dioxide, silicon dioxide and iron oxide described in Patent Documents 9 and 10 contains at least a part of iron atoms in order to improve the weather resistance and light resistance of titanium dioxide. Although it has improved the weather resistance and light resistance by solid solution in titanium crystals and coating with fine particles with silicon dioxide, the resulting coating is still insufficient in terms of weather resistance and light resistance Met. Also in this case, since iron oxide itself has a yellowish color, the cured film obtained from these composite oxide sols has a drawback that it is somewhat yellowish.

  Furthermore, the composite inorganic oxide sol of Patent Document 11 is colorless and transparent, and the film obtained from the coating composition using this sol is initially colorless and transparent. However, as the titanium oxide is reduced over time, the coating may become bluish, which is not sufficient in terms of weather resistance and light resistance.

  Patent Documents 12 and 13 disclose nitriding of other oxides such as silicon oxide, iron oxide, titanium oxide, cerium oxide, tin oxide, tungsten oxide, tantalum oxide, antimony oxide, zirconium oxide, and aluminum oxide. Although oxides of silicon and aluminum cannot be used as a primer for high refractive index due to low refractive index, titanium, cerium, tin, tungsten, antimony, etc. Since the oxide has a strong photoactivity, there is a problem of deteriorating the primer layer over time.

  More recently, when dyeing plastic lenses, the hard coat layer and primer layer may be dyed and processed into colored plastic lenses. Since these oxides are highly photoactive, the dyes decompose and the colored lenses Has the disadvantage of fading. Moreover, since the oxides of zirconium and tantalum are unstable, if they are blended in a primer coating at a high concentration, they aggregate or precipitate and cannot be used. In addition, nitrides, borides, and sulfides are high in refractive index, but most of them are colored, so they cannot be blended in large quantities, and it is difficult to obtain a transparent primer with a high refractive index. .

  As a result of intensive studies to solve the problems in the prior art as described above, the present inventors have solved the above problems if niobium-based oxide fine particles that have not been used so far are used for forming a transparent film. It was found that both can be solved.

The gist of the present invention is as follows.
[1] A coating solution for forming a transparent film, comprising niobium-based oxide fine particles and a matrix-forming component.
[2] A composite in which the niobium-based oxide fine particles contain at least one oxide selected from oxides of Fe, Ce, Si, Zr, Al, Ti, Sn, Sb, W, and Zn together with niobium oxide. A coating liquid for forming a transparent film of [1], which is oxide fine particles.
[3] The niobium-based oxide fine particles are [1] or [2] niobium-based oxide fine particles or other inorganic oxide fine particles as core particles, and the core particles are Nb, Fe, Ce, Si, Zr, Al. The coating liquid for forming a transparent film according to [1] to [2], which has a core-shell structure coated with one or more oxides selected from oxides of Ti, Sb, W, and Zn.
[4] The coating liquid for forming a transparent film according to [1] to [3], wherein the niobium-based oxide fine particles have a surface treated with an organosilicon compound or an amine-based compound.
[5] The coating liquid for forming a transparent film according to [1] to [4], wherein the matrix forming component is a resin selected from one or more of a thermosetting resin, a thermoplastic resin, and an ultraviolet curable resin.
[6] The coating liquid for forming a transparent film according to [1] to [4], wherein the matrix-forming component is a hydrolyzable organosilicon compound and / or a hydrolyzate of the hydrolyzable organosilicon compound.
[7] A substrate with a transparent coating, which has a transparent coating formed on the surface of the substrate using the transparent coating solution of [1] to [6].

  The film formed on the substrate using the coating liquid for forming a transparent film according to the present invention has high transmittance, is colorless and transparent, and has adhesion with the substrate, weather resistance, light resistance, and ultraviolet absorption characteristics. It is excellent in flexibility, chemical resistance, hot water resistance and dyeing property, and has high surface hardness, excellent scratch resistance and impact resistance. Therefore, these coated substrates are suitably used for various optical lenses such as spectacle lenses and cameras, various display element filters, and the like.

  Further, since the film obtained from the coating liquid for forming a transparent film according to the present invention has a high refractive index, such a film is formed on the surface of a lens substrate having a refractive index of 1.54 or more, particularly 1.66 or more. In the case of forming the lens, a high refractive index film equivalent to the lens substrate can be formed, so that a high refractive index lens without interference fringes can be obtained.

Hereinafter, the coating liquid for forming a transparent film according to the present invention will be described in more detail.
[Transparent coating solution]
The coating liquid for forming a transparent film according to the present invention contains niobium oxide fine particles and a matrix forming component.

[Niobium oxide fine particles]
The niobium-based oxide fine particles used in the coating liquid for forming a transparent film of the present invention are fine particles mainly composed of niobium oxide (Nb ₂ O ₅ ). Even if the niobium-based oxide fine particles are composed of niobium oxide alone, Nb ₂ O ₅ and Fe, Ce, Si, Zr, Al, Ti, Sn, Sb, W, Zn
It may be composed of a composite oxide containing one or more oxides selected from such oxides. Among these, composite oxide fine particles containing one or more oxides selected from oxides of Fe, Ce, Si, Zr, Al, Ti, and Sn can be suitably used. When any of the oxides of Fe, Ce, Zr, Ti, and Sn is included, a coating solution having excellent stability can be obtained. Further, the obtained transparent film has a high refractive index and is transparent, and can suppress interference fringes even when the refractive index of the base material is 1.60 or more, particularly 1.66 or more, hot water resistance, weather resistance, It excels in light resistance, ultraviolet absorption performance, scratch resistance, abrasion resistance, flexibility and dyeability, and also has excellent adhesion to the substrate.

  In addition, when any of Si, Al, W, and Sn oxides is included, the stability of the coating solution is further improved, and the obtained transparent film has a high refractive index and is transparent, and the refractive index of the substrate is high. Interference fringes can be suppressed even if it is 1.54 or more, particularly 1.60 or more, hot water resistance, weather resistance, light resistance, ultraviolet absorption performance, scratch resistance, abrasion resistance, flexibility and dyeability. In addition, it has excellent adhesion to the substrate.

The content of niobium oxide in the niobium-based oxide fine particles is 50% by weight or more as Nb ₂ O ₅ ,
Furthermore, it is preferable that it exists in the range of 60 to 95 weight%.
When the content of niobium oxide in the niobium-based oxide fine particles is less than 50% by weight as Nb ₂ O ₅ , the interference fringes may not be sufficiently suppressed depending on the refractive index of other oxides. Depending on the type of other oxides, the hot water resistance, weather resistance, light resistance, and ultraviolet absorption performance may be insufficient.

  Further, when the niobium-based oxide fine particles are composed only of niobium oxide, the niobium oxide is preferably a crystalline niobium oxide, and the higher the crystallinity, the higher the refractive index, which is suitable for the transparent film of the present invention. Can be used.

When the niobium-based oxide fine particles include other oxides, for example, when the oxides of Ti are included, it is preferably crystalline TiNb ₂ O ₇ , TiNb ₆ O _17, etc., and the oxides of Sb are included. In this case, crystalline SbNbO ₄ or the like is preferable, and when Fe oxide is included, crystalline FeNbO ₄ or the like is preferable.

The average particle diameter of the niobium oxide fine particles is preferably in the range of 1 to 100 nm. More preferably, it is 2-60 nm, Most preferably, it is the range of 2-15 nm.
If the average particle size exceeds 100 nm, the resulting transparent coating may become cloudy. If the average particle size is less than 1 nm, the resulting transparent coating has insufficient hardness and is inferior in scratch resistance and abrasion resistance. At the same time, the refractive index may not be sufficiently high.

As the niobium-based oxide fine particles used in the present invention, the niobium-based oxide fine particles or other inorganic oxide fine particles are used as core particles, and the core particles are Nb, Fe, Ce, Si, Zr, Al, Ti, Sb.
Particles having a core-shell structure coated with one or more oxides selected from oxides of W, Zn and Zn can also be suitably used.

  When other inorganic oxide fine particles are used as the core particles, the other inorganic oxides are composed of Ti, Zr, Fe, Ce, Sn and complex oxides containing these as main components, and the refractive index is 1.8 or more. Any inorganic oxide particles can be suitably used.

Further, when niobium-based oxide fine particles are used as core particles, the shell does not necessarily contain niobium oxide, but when other inorganic oxide fine particles are used as the core particles, the shell may contain niobium oxide. In any case, the content of niobium oxide in the niobium-based oxide fine particles to be finally used is preferably 50% by weight or more as Nb ₂ O ₅ .

Also in the case of niobium-based oxide fine particles having a core-shell structure, the average particle diameter is preferably 1 to 100 nm, more preferably 2 to 60 nm, and particularly preferably 2 to 15 nm.
A method for producing such niobium-based oxide fine particles that can be used in the present invention will be described.
[Production Method of Niobium Oxide Fine Particle Dispersion]
The niobium-based oxide fine particles used in the present invention require a solution obtained by dissolving and / or peptizing a niobic acid dispersion by adding hydrogen peroxide when the main component of the fine particles is a niobium oxide. According to the above, it is produced by hydrothermal treatment at 80 to 300 ° C. in the presence of a compound other than the niobium compound.

Niobic acid is not particularly limited as long as it can be dissolved and / or peptized in hydrogen peroxide, and conventionally known niobic acid can be used. Here, niobic acid refers to a hydroxide of niobium (or a hydrate of niobium oxide), which can be represented by Nb ₂ O ₅ .nH ₂ O, where n is approximately in the range of 1 to 5. .

Such niobic acid can be obtained, for example, by the following method.
(1) Using niobium pentachloride and / or niobium oxychloride as a starting material, hydrolyzing and then washing.
(2) A solution obtained by dissolving niobium metal or niobium oxide with an acid or an aqueous solution of niobium pentafluoride is neutralized and / or hydrolyzed and then washed.
(3) The solution of orthoniobate or metaniobate is neutralized and / or hydrolyzed and then washed.

In the above, acid or alkali can be added to neutralization or hydrolysis as necessary. As the alkali, ammonia water is suitable.
The washing can be performed by an ion exchange resin method, a filter method, an ultrafiltration method, or the like. The alkali and the acid radical in the niobic acid after washing are 0.5% by weight with respect to Nb ₂ O ₅ of niobic acid. % Or less is preferable. If it exceeds 0.5% by weight, there will be too much alkali and / or acid radicals in the finally obtained niobium oxide fine particle dispersed sol, and the stability and transparency of the sol will decrease, and there will be no stability. Therefore, there is a problem that the use is limited.

  When producing composite oxide particles composed of niobium oxide and another oxide, a mixed dispersion or mixed solution of compounds of elements other than niobium is used together with the niobic acid dispersion. Elements other than niobium are as described above, and nitrates, sulfates, chloride salts, organic acid salts, oxides, and the like of these elements are used. Specifically, ferrous chloride, ferric chloride, ferric nitrate, cerium nitrate, aluminum chloride, aluminum sulfate, titanium tetrachloride, titanyl sulfate, tin nitrate, antimony pentachloride, ammonium tungstate, zinc nitrate, Examples thereof include iron oxide, cerium oxide, silica, aluminum oxide, titanium oxide, tin oxide, antimony oxide, tungsten oxide, and zinc oxide. Here, the oxide includes hydroxide and hydrate, and these sols are preferably used.

Hydrogen peroxide is added to a mixed dispersion or solution of compounds of elements other than niobic acid and niobium, or to a dispersion or solution of compounds of elements other than niobium (hereinafter referred to as niobic acid, etc.). Is converted from niobic acid or the like to an oxide, and hydrogen peroxide having a concentration of approximately 5 to 40% by weight to 1 part by weight of the total oxide is converted to H ₂ O ₂ by 1.5 to 6 parts by weight. Preferably 2
Add ~ 4 parts by weight. The concentration of niobic acid, etc. at this time is 0.5 to 10 in terms of oxide.
It adjusts so that it may become weight%, Preferably 1-5 weight%.

Hydrogen peroxide is added to the niobic acid dispersion or solution prepared as described above and a dispersion or solution with a compound of an element other than niobium (hereinafter collectively referred to as niobic acid or the like). The amount used is 1.5 to 6 weights by converting niobic acid or the like into an oxide, and converting hydrogen peroxide having a concentration of approximately 5 to 40% by weight into H ₂ O ₂ with respect to 1 part by weight of the total oxide. Parts, preferably 2-4 parts by weight. The concentration of niobic acid, etc. at this time is 0.5 to 0.5 in terms of oxide.
It is adjusted to 10 wt%, preferably 1 to 5 wt%.

When the amount of H ₂ O ₂ used is small, niobic acid and compounds of elements other than niobium are not completely dissolved and / or peptized and unreacted niobic acid and the like remain, which is not preferable. When the number of moles of H ₂ O ₂ with respect to niobic acid or the like is too large, the dissolution and / or peptization rate is high, and the reaction is completed at a low temperature or in a short time, but excess hydrogen peroxide remains in the system. In other words, it is not economical, and there is a risk that oxygen gas is generated during the hydrothermal treatment or that the pressure increases.

If the amount of H ₂ O ₂ used for niobic acid or the like is within the above range, niobic acid can be completely dissolved and / or peptized in 0.5 to 5 hours, depending on the heating and melting temperature.
Also, when the concentration of niobic acid or the like is low, the production efficiency is low because the concentration is too low, and the viscosity of the niobium-based oxide fine particle dispersion obtained even if the concentration of niobic acid or the like is too high becomes too stable or stable. It may be missing.

  In addition, it can heat as needed when melt | dissolving and / or peptizing. The heating temperature is preferably in the range of approximately 30 to 100 ° C. If the heating temperature is low, dissolution and peptization may be insufficient, and the particle size distribution of the niobium oxide fine particle dispersion obtained by hydrothermal treatment may become non-uniform, and dissolution and / or dissolution may occur. The glue time may become too long and the production efficiency may be lowered. Further, when the heating temperature exceeds 100 ° C., the dissolution and / or peptization time is shortened, but the particle size distribution of the fine particles of the niobium oxide fine particle dispersion obtained by hydrothermal treatment tends to be non-uniform. is there.

  As described above, the first method for producing niobium-based oxide fine particles used in the present invention comprises adding hydrogen peroxide to a niobic acid dispersion liquid / solution or a mixed dispersion liquid or mixture of compounds of elements other than niobic acid and niobium. In addition, the solution obtained by dissolution and / or peptization is hydrothermally treated at 80 to 300 ° C. In the second production method, hydrogen peroxide is added to a niobic acid dispersion and dissolved and / or peptized, and hydrogen peroxide is added to and dissolved in a dispersion or solution of a compound of an element other than niobium. And / or the solution obtained by peptization is mixed and hydrothermally treated at 80 to 300 ° C. In the third production method, a dispersion or solution of a compound of an element other than niobium is mixed with a solution obtained by dissolving and / or peptizing hydrogen peroxide in a niobic acid dispersion, Hydrothermally treat with.

  The niobium-based oxide fine particles used in the present invention can be prepared by any of these methods. If the hydrothermal treatment temperature is low, niobic acid is not sufficiently oxidized by dehydration. Further, the obtained niobium-based oxide fine particle dispersion may lack stability, and if the hydrothermal treatment temperature is in the range of 80 to 300 ° C., not only niobium-based oxide fine particles having a uniform particle diameter can be obtained, A niobium oxide fine particle dispersion having excellent stability can be obtained. A preferable hydrothermal treatment temperature is in the range of 100 to 250 ° C.

The hydrothermal treatment described above is preferably performed in the presence of the following particle growth regulator.
Particle Growth Modifier As the particle growth regulator used in the present invention, carboxylic acid or carboxylate, hydroxycarboxylic acid (having a carboxyl group and an alcoholic hydroxyl group in one molecule), and hydroxycarboxylate are used.

  Specifically, monocarboxylic acids and monocarboxylic acid salts such as formic acid, acetic acid, succinic acid, acrylic acid (unsaturated carboxylic acid), gluconic acid, malic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid And polyvalent carboxylic acids such as sebacic acid, maleic acid, fumaric acid, and phthalic acid, and polyvalent carboxylic acid salts.

  Further, α-lactic acid, β-lactic acid, γ-hydroxyvaleric acid, glyceric acid, tartaric acid, citric acid, tropic acid, hydroxycarboxylic acid and hydroxycarboxylate of benzylic acid can be mentioned.

  Such a particle growth regulator may be hydrolyzed in addition to the niobium compound when preparing niobic acid, or may be added to the prepared niobic acid or the like, or dissolved or peptized by adding hydrogen peroxide. It may be added after.

The amount of the particle growth regulator used is the molar ratio (Pm) / (Nm) of the total number of moles (Nm) of niobium compounds, niobic acid, and compounds of elements other than niobium and the number of moles of grain growth regulator (Pm). Is 0.0
It is preferably in the range of 1-1, more preferably 0.1-0.5.

  When the molar ratio is small, the particle growth regulator is insufficient, and the niobium oxide fine particles obtained by hydrothermal treatment may have nonuniform particle sizes or coarse particles. Even if the molar ratio is too high, the effect of suppressing the generation of coarse particles evenly and making the particle diameter more uniform, and in addition, there are many particle growth regulators and the yield may be reduced. There is a problem that the economy is reduced.

In the present invention, the hydrothermal treatment is preferably performed in the presence of seed particles.
Seed particles include group III of the periodic table such as Al, group IV such as Ti, Zr, Si, and Sn, group V such as V, Nb, and Sb, group VI such as W, and group VIII such as Fe. An inorganic compound of one or more elements selected from the group is used.

  As the form of the inorganic compound, salts, oxides, hydroxides, oxyacids or oxyacid salts are used. Preferably, a gel or sol such as oxide, hydroxide or oxyacid is used. Among them, the sol has high dispersibility, stability, and uniform particle size, and niobium-based oxide fine particles having a uniform particle size can be obtained.

  The average particle size of the seed particles is preferably less than 5 nm, and particularly preferably in the range of 0.5 to 3 nm. Moreover, it is preferable that the usage-amount of a seed particle exists in the range of 1-30 weight% of the total weight as an oxide of the compound of niobium compound, niobic acid, and elements other than niobium, Furthermore, it is 2-20 weight%. If the amount of seed particles used is small, the effect of making the particle diameter uniform may be insufficient, and if the seed particles are other than niobium compounds even if the amount of seed particles used is excessive, the inclusion of niobium-based oxides Insufficient amounts may reduce the semiconductor, optical properties, dielectric properties, ultraviolet shielding properties, light resistance, weather resistance, and the like of the resulting niobium-based oxide fine particles, thereby limiting the application.

Furthermore, in the present invention, hydrothermal treatment can be performed in the presence of core particles instead of the seed particles. As the core particles, oxide or hydroxide particles having the same kind as the seed particles and having an average particle diameter of 5 to 50 nm, preferably 10 to 30 nm are used.
The amount of the core particles used is preferably in the range of 5 to 50% by weight, more preferably 10 to 30% by weight, based on the total weight of oxides of niobium compounds, niobic acid, and compounds of elements other than niobium. In particular, the content of Nb ₂ O _{5 in} the finally obtained niobium-based oxide fine particles is preferably 50% by weight or more. When the content of Nb ₂ O ₅ in the niobium-based oxide fine particles is small, the semiconductor, optical properties, dielectric properties, ultraviolet shielding properties, light resistance, weather resistance, etc. of the obtained niobium-based oxide fine particles are insufficient. There is.

Particles having a core-shell structure can be prepared by the following method.
The niobium-based oxide fine particles obtained as described above are used as core particles, and (1) a niobic acid dispersion / solution, (2) a dispersion or solution of a compound of elements other than niobic acid and niobium. (3) A solution obtained by adding hydrogen peroxide to a dispersion or solution of a compound of an element other than niobium and dissolving and / or peptizing is mixed, and hydrothermally treated at 80 to 300 ° C. A niobium oxide fine particle dispersion can also be prepared.

  In this case, niobium-based oxide particles having a core-shell structure in which the niobium-based oxide fine particles are the core and the core particles are coated with an oxide derived from a solution in which niobic acid or the like is dissolved and / or peptized. A fine particle dispersion is obtained. For example, in the case of (1), niobium-based oxide fine particles obtained by coating niobium-based oxide fine particles as core particles with niobium oxide are obtained. In the case of (2), niobium-based oxide fine particles as core particles are converted to niobium. Niobium-based oxide fine particles coated with a complex oxide of an element other than acid and niobium can be obtained. In the case of (3), the niobium-based oxide fine particles as core particles are converted to oxides or complex oxides that do not contain niobium oxide. Niobium-based oxide fine particles coated with can be obtained.

  Furthermore, inorganic oxide fine particles composed of oxides other than niobium are used as the core particles, and (1) niobic acid dispersion / solution or (2) compounds of elements other than niobic acid and niobium are used in the fine particle dispersion. It is also possible to prepare a niobium oxide fine particle dispersion by mixing a solution obtained by adding hydrogen peroxide to a dispersion or solution of the above and dissolving and / or peptizing the solution and hydrothermally treating at 80 to 300 ° C.

The elements other than niobium in the above are preferably at least one selected from Fe, Ce, Si, Zr, Al, Ti, Sn, Sb, W, and Zn. The compounds of elements other than niobium are the same as described above. A compound is used. The hydrothermal treatment temperature is preferably in the range of 80 to 300 ° C, more preferably 100 to 250 ° C, as described above.

  The niobium-based oxide fine particle dispersion obtained as described above can be used after removing remaining ions with an ion exchange resin or the like, if necessary. However, the niobium oxide fine particle dispersion obtained in the present invention is not necessarily required because impurities and ions are reduced in advance in the washing step.

  Moreover, it can also be used by substituting with a desired solvent such as alcohols such as methanol and ethanol, glycols such as 1.3-butylene glycol, and glycerin with a rotary evaporator. The niobium oxide fine particle dispersion obtained by the above method is very stable even when the dispersion medium is an organic solvent, and does not aggregate, gel, or precipitate.

The average particle size of the fine particles of the niobium-based oxide fine particle dispersion obtained by the production method of the present invention is generally in the range of 1 to 100 nm, preferably 2 to 60 nm.
If the average particle size is small, the stability may be insufficient and a fine particle dispersed sol may not be obtained.If the average particle size is large, the particles are too large to settle or have poor transparency. May be sufficient.

Moreover, the niobium oxide fine particle dispersion obtained as described above can be used for various purposes as it is, or can be diluted or concentrated as necessary.
The concentration of such a niobium-based oxide fine particle dispersion is preferably in the range of 5 to 40% by weight, more preferably 10 to 30% by weight as an oxide. Within this range, there is no practical problem and the dispersibility of the dispersion is excellent.

In the present invention, the obtained niobium-based oxide fine particle dispersion can be dried and calcined as necessary to be used as niobium-based oxide fine particles.
The drying temperature is not particularly limited as long as niobium oxide fine particle powder can be obtained, and it is usually dried at room temperature to 120 ° C.

  The firing temperature may be in the range of 300 to 700 ° C. When firing in such a temperature range, oxidization or crystallization sufficiently proceeds depending on the component, and niobium excellent in optical properties, ultraviolet shielding properties, weather resistance, etc. Systemic oxide fine particles can be obtained. When firing at a high temperature, depending on the particle size, the particles may aggregate or be fused together.

  In the present invention, the niobium-based oxide fine particle dispersion obtained by the above method may be dried in advance and used in the form of fine powder. The dispersion medium composed of water and / or an organic solvent may be colloidal. When used in the state of a dispersion dispersed in, an excellent substrate with a transparent film can be obtained.

  The niobium-based oxide fine particles can be used by treating the surface with silicone, a fluorine compound or the like in order to impart water repellency and oil repellency when blended in the coating liquid for forming a transparent film.

  Furthermore, the niobium-based oxide fine particles can be used by surface treatment or surface coating with a hydrolyzable organosilicon compound such as a silane coupling agent. The surface treatment method or the surface coating method is not particularly limited, and for example, the surface is coated with an organosilane compound by adding a hydrolyzable organosilicon compound to the dispersion and reacting for a predetermined time at a predetermined temperature.

The kind of the hydrolyzable organosilicon compound used here is appropriately selected according to the application.
Specific examples of hydrolyzable organosilicon compounds for surface modification include tetraalkoxysilanes such as tetramethoxysilane and tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriacetoxysilane, and methyltripropoxy. Silane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropyltripropoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ- (β- Trialkoxy or triacyloxysilanes such as lysidoxyethoxy) propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and dimethyldimethoxysilane, Dimethyldiethoxysilane, phenylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylphenyldiethoxysilane, γ-chloropropylmethyldimethoxysilane, dimethyldiacetoxysilane, γ-methacryloxypropyl Dialkoxysilanes or diacyloxysilanes such as methyldimethoxysilane, γ-mercaptoprovirmethyldimethoxysilane, γ-aminopropylmethyldimethoxysilane Or trimethylchlorosilane, and the like can be used alone or in combination of two or more.

  In order to improve the surface of the niobium oxide fine particles, the alcohol solution of the hydrolyzable organosilicon compound and the niobium oxide fine particle dispersion are mixed, and an acid or alkali is used as a hydrolysis catalyst as necessary. And reacting at a constant temperature for a certain period of time, and then separating the water in the mixed solution to produce niobium oxide fine particles dispersed in an organic solvent. If it does in this way, the dispersion stability in an organic solvent will improve.

[Matrix forming component]
As the matrix forming component which is another component of the coating liquid for forming a transparent film according to the present invention, a transparent resin selected from a thermosetting resin, a thermoplastic resin and an ultraviolet curable resin is used. Mixtures or copolymer resins of seeds or more are also used.

Specific examples of such resins include epoxy resins, acrylic acid ester and / or methacrylic acid ester copolymers (including copolymers with other vinyl monomers), polyamides, polyesters ( Alkyd resin, unsaturated polyester resin), melamine resin, urea resin and other amino resins, urethane resin, polycarbonate resin, polyvinyl acetate, polyvinyl resin, silicone resin, acrylate UV curable resin, epoxy UV curable resin, Examples thereof include acrylate γ-ray curable resins and diethylene glycol bisallyl carbonate resins.

  In addition to the above resins, hydrolyzable organosilicon compounds are also suitable as the matrix forming component of the coating liquid according to the present invention. As such a hydrolyzable organosilicon compound, for example, a silane compound represented by the following general formula (I) is used.

(Wherein, a and b are integers of 0 to 2, and a + b is 1 to 3. R ¹ is an alkyl group, an alkenyl group, a phenyl group, or a halogenated hydrocarbon group; ² is
An epoxy group, an amino group, an amide group, a mercapto group, a methacryloxy group, a cyano group, a vinyl group, an organic group containing an aromatic ring nucleus-substituted with halogen, and X is a hydrolyzable group such as a halogen atom or alkoxyl A group, an alkoxyalkoxyl group, and an acyloxy group. )
Specific examples of the silane compound represented by the formula (I) include tetrafunctional silanes such as tetramethoxysilane and tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, N-β- (aminoethyl) 3 functional silanes such as γ-aminopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-cyanopropyltrimethoxysilane, γ-morpholinopropyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, 3 1 of functional silane And bifunctional silanes in which a part is substituted with a methyl group, an ethyl group, or a vinyl group. These organosilicon compounds may be used in combination of two or more.

  These organosilicon compounds can be used as they are or after being hydrolyzed. When such an organosilicon compound is used in the coating liquid for forming a transparent film according to the present invention, the coating liquid may further contain a curing catalyst in order to promote curing of the film formed by the organosilicon compound. Good.

Specific examples of such a curing catalyst include n-butylamine, triethylamine,
Amines such as guanidine, amino acids such as glycine, imidazoles such as 2-methylimidazole, 2,4-diethylimidazole and 2-phenylimidazole, metal acetylacetonates such as aluminum acetylacetonate, titanium acetylacetonate and chromium acetylacetonate Organic acid metal salts such as sodium acetate, zinc naphthenate and tin octylate, Lewis acids such as SnCl ₄ , TiCl ₄ and ZnCl _2, and magnesium perchlorate.

  The coating liquid for forming a transparent film according to the present invention is prepared by mixing the niobium-based oxide fine particles and the matrix-forming component as described above with an organic solvent and, if necessary, other components.

In the coating liquid for forming a transparent film according to the present invention, the content of the niobium-based oxide fine particles is such that the weight of the total oxide of Nb ₂ O ₅ and other oxides in the niobium-based oxide fine particles Nb ₂ O ₅ + other oxide + matrix solid content) is used in an amount of 1 to 90 parts by weight, preferably 10 to 80 parts by weight per 100 parts by weight.

  If the niobium oxide fine particles are less than 1 part by weight as the total oxide, there is no effect of adding the niobium oxide fine particles, and if it exceeds 90 parts by weight, cracks are likely to occur in the coating, and the adhesion to the substrate is also good. This may cause problems such as lowering of transparency and transparency. Further, the solid content concentration (total oxide + matrix solid content) in the coating solution at this time is not particularly limited as long as it can be applied, and is appropriately selected according to the purpose.

Specific examples of the organic solvent used in the coating solution for forming a transparent film include alcohols such as methanol, ethanol and isopropyl alcohol, ketones such as acetone and methyl ethyl ketone, cellosolves such as methyl cellosolve and ethyl cellosolve, N, Amides such as N-dimethylformamide, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl acetate such as ethyl acetate and butyl acetate, γ-butyl lactone, N-methyl-2-pyrrolidone solvents alone or in combination You may mix and use the above.

In addition, this coating solution contains surfactants, ultraviolet absorbers, antioxidants, pigments, dyes, antistatic agents, conductive substances, clay modifiers, etc., depending on the use of the substrate for forming the transparent film. It may be added. Further, when a polyfunctional epoxy compound, polyhydric alcohol, polycarboxylic acid, polycarboxylic acid anhydride, hindered amine compound, or the like is added, the dyeing property of the formed film is improved or various durability is improved.
[Transparent coating]
The transparent film according to the present invention is obtained by applying the above-described coating liquid for forming a transparent film on the surface of a substrate such as glass or plastic by a method such as dipping, spinner, spray, roll coater, or flexographic printing. It is obtained by a method of drying and then curing by heating in this way.

The film thickness of the transparent coating of the present invention thus obtained is usually 0.05 to 20 μm, preferably 0.08 to 7 μm. If the film thickness of the transparent film is small, the film thickness of the transparent film is so thin that the stress applied to the surface of the transparent film cannot be sufficiently absorbed, and so-called hard coat functions such as scratch resistance may be insufficient. . If the film thickness of the transparent film is too thick, it becomes difficult to apply and dry the film uniformly so that the strength and transparency of the transparent film obtained by the generation of cracks and voids are insufficient. It may become.

Substrate As a substrate such as glass and plastic used in the present invention, specifically, various optical lenses such as spectacle lenses and cameras, various display element filters, looking glass, window glass, automobiles, paint films and light covers Can be mentioned. In particular, in order to obtain a thin synthetic resin lens excellent in appearance and durability, a lens base having a refractive index of 1.54 or more is preferable, and further, transparency, dyeability, heat resistance, water absorption, bending strength, As a base lens that can satisfy desired characteristics in terms of impact resistance, weather resistance, workability, etc., a sulfur-containing urethane type, (meth) acrylic type, episulfide type lens base material, etc. are suitable, and the refractive index is 1. A lens base material of about .66 to 1.71 or higher and simultaneously having an Abbe number exceeding 30 is suitable.

  In producing a substrate with a transparent coating, the surface of the substrate is treated with an alkali, acid or surfactant in advance for the purpose of improving the adhesion between the substrate, for example, the lens substrate and the transparent coating, Polishing with organic fine particles, primer treatment or plasma treatment may be performed.

Antireflection Film In the present invention, a single-layer or multilayer antireflection film made of a conventionally known inorganic substance can be further provided on the transparent coating for the purpose of antireflection. By providing an antireflection film, reflection can be reduced and transmittance can be improved. Examples of inorganic substances include SiO, SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ , MgF ₂ , Ta ₂ O _{3 and the} like, and they can be formed by a thin film forming method such as a vacuum evaporation method. Alternatively, it can be formed by a conventionally known wet film forming method such as applying a coating solution containing SiO ₂ as a main component and containing a low refractive index component, if necessary, and drying.
Primer film In the present invention, a primer film may be provided between the substrate and the transparent film. By providing a primer film, impact resistance and adhesion can be improved. The primer film can be formed using a coating liquid containing a coating resin, preferably a polyurethane resin, a polyester resin, an epoxy resin, an acrylic resin, or the like, as a matrix.

[Example]
EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.
[Example 1]
Nb based oxide particles (A1) were mixed to prepare a concentration 35.3% by weight of the KNbO ₃ solution 1917g of water 23083g of the dispersion, the concentration of 2.71 wt% of KNbO ₃ solution, to which the 1 mol / L acetic acid Added and neutralized. The pH at this time was 5.5. This was filtered and washed with distilled water to obtain 1990 g of niobic acid gel. The solid content concentration of this gel was 24.01% by weight in terms of Nb ₂ O ₅ .

After adding 33540 g of water to 1460 g of the resulting niobic acid gel and stirring sufficiently, 4000 g of 35% by weight hydrogen peroxide was added and dissolved by heating at 80 ° C. for 2 hours. Water was added to the resulting solution to adjust the concentration to 0.5% by weight in terms of Nb ₂ O ₅ , and then hydrothermal treatment was performed at 150 ° C. for 18 hours in an autoclave.

Next, this was concentrated to obtain 3500 g of an aqueous dispersion of niobium oxide fine particles (A1) having a concentration of 10% by weight in terms of Nb ₂ O ₅ .
Next, a portion of the niobium-based oxide fine particle (A1) dispersion is replaced with methanol as the dispersion medium and concentrated to obtain a niobium-based oxide fine particle (A1) methanol dispersion having a solid content of 20% by weight. Obtained.

For each particle, the average particle size was measured by a laser method (manufactured by PARTICS SIZING SYSTEM: NICOM 380), the uniformity of the particle size was observed, the acid radicals in the particles were further measured, and the results are shown in Table 1. Further, the stability, transparency, and refractive index of the particles were evaluated for each dispersion, and the results are shown in Table 1.
Uniform Niobium Oxide Fine Particles (A1) Transmission electron micrographs of niobium oxide fine particles (A1) collected from a methanol dispersion were taken and evaluated according to the following criteria.
Almost no particles smaller than 1/2 of the average particle diameter or particles larger than 2 times are recognized: ○
Slightly less than 1/2 the average particle size or more than twice the average particle size: Δ
Particles with an average particle size of ½ or less or twice or more are clearly recognized: X
Measurement of methanol dispersion stability Viscosity of niobium oxide fine particle dispersion immediately after adjustment to a concentration of 20% by weight in terms of Nb ₂ O ₅ ,
The viscosity after heating at 50 ° C. for 10 days was measured and evaluated according to the following criteria.
Viscosity increase rate is less than 10%: ◎
Viscosity increase rate less than 10-20%: ○
Viscosity increase rate 20 to less than 50%: Δ
Viscosity increase rate 50% or more: ×
Transparency Measurement A niobium oxide fine particle dispersion liquid adjusted to a concentration of 0.1% by weight in terms of Nb ₂ O ₅ was placed in a quartz cell having a thickness of 10 mm, and a transmittance measuring device (manufactured by JASCO Corporation: V- The transmittance was measured at 550 and a wavelength of 550 nm, and evaluated according to the following criteria.

Transmission 90% or more: ○
Transmittance less than 90%: ×
Preparation of coating solution for forming transparent film (A1) In a flask equipped with a stirrer, 363.47 g of methanol, 339.35 g of γ-glycidoxypropyltrimethoxysilane and 39.53 g of tetraethoxysilane were mixed, and the reaction solution was mixed. While maintaining the temperature at 5 ° C., 93.2 g of 0.05 mol / L hydrochloric acid aqueous solution was added with stirring and stirred for 30 minutes. Subsequently, 35 g of a silicon surfactant (manufactured by Nippon Unica Co., Ltd .: L-7604),
Further, 0.03 g of aluminum acetyl acetate was added, followed by aging at 3 ° C. for 24 hours, then 565 g of isopropanol was added, and then 847.8 g of the above-mentioned niobium oxide fine particle (A1) methanol dispersion was added and stirred well. Then, aging was further performed at 3 ° C. for 24 hours to obtain a coating liquid for forming a transparent film (A1).

A plastic lens (manufactured by Mitsui Toatsu Co., Ltd .: MR-7) is used as a base material for forming the lens (A1) with a transparent coating, and first immersed in an aqueous NaOH solution having a concentration of 13% by weight at 47 ° C. for several minutes. The material surface was thoroughly washed with water.

  Next, this lens substrate is immersed in the coating solution (A1) for forming a transparent film, then pulled up at a pulling rate of 80 mm / min, dried at 90 ° C. for 18 minutes, and heat-cured at 104 ° C. for 90 minutes to obtain a lens with a transparent film (A1) was formed.

The following characteristics were evaluated for the obtained lens with transparent coating (A1). The results are shown in Table 1.
(A) High refractive performance The case where the refractive index obtained from the analysis result of the reflection interference spectrum of the transparent coating surface of the lens (A1) with a transparent coating is 1.65 or more was evaluated as ◯.
(B) Scratch resistance The # 000 steel wool is reciprocated 10 times on the film surface of the lens (A1) with a transparent coating while applying a load of ² kg / cm ² , and the coating is rubbed with the steel wool. They were visually observed and classified into the following stages for evaluation.

A: scarcely scratched B: slightly scratched C: severely scratched (c) Appearance The presence or absence of coloring of the transparent coated lens (white lens) that does not rotate dyeing was evaluated with the naked eye.
(D) Transparency The average visible light transmittance of a lens with a transparent coating (white lens) that does not rotate staining with a spectrophotometer was measured.
(E) Dyeing property A lens (A1) with a transparent coating is immersed for 5 minutes in 92 ° C hot water in which three types of disperse dyes of red, blue and yellow are dissolved, and SM color computer (Suga Test Instruments Co., Ltd.) Was used to measure the light attenuation rate at a wavelength of 550 nm and evaluated as follows.

○… Light attenuation rate is 30% or more △… Light attenuation rate is 20% or more and less than 30% ×… Light attenuation rate is less than 20% (f) Adhesion The lens with transparent coating (A1) is placed in 70 ° C warm water. After immersion for 2 hours, 11 parallel line-shaped scratches were made on the lens surface vertically and horizontally with a 1 mm interval, and 100 cells were formed, and after the cellophane tape was adhered and peeled, the film remained without peeling off. Evaluation was based on the number of squares.
(G) Clouding degree A lens (A1) with a transparent coating is installed between a black background and a three-wavelength daylight fluorescent lamp, and the pattern of light that passes through this lens and appears in the background is visually observed. Was evaluated in three stages: ○, △, and ×.
(H) Haze Using a haze meter (manufactured by Suga Test Instruments Co., Ltd.), the haze of a transparent coated lens (white lens) that was not dyed was calculated according to the following formula.
[Equation 1]
Haze = (diffuse light transmittance / total light transmittance) × 100 (%)
(I) Weather resistance After exposure for 400 hours using a weather meter using carbon arc (manufactured by Suga Test Instruments Co., Ltd.), the following evaluation was performed.
1) Appearance: According to (c) above.
2) Transmittance: According to (d) above.
3) Adhesiveness: The same test as in (f) was performed on the exposed surface.
(J) Long-term stability After the coating liquid for forming a transparent film was stored at 5 ° C. for 25 and 45 days, a transparent film was formed in the same manner as described above, and (a) to (g) were evaluated. Differences from the transparent coating formed with the coating solution for forming a transparent coating were evaluated in three stages, ◯, Δ, and ×.

Table 1 shows the results of (a) to (j).
[Example 2]
Preparation of Niobium Oxide Fine Particle (A2) Dispersion Niobium Oxide in the same manner as in Example 1 except that instead of the 1 mol / L acetic acid solution of Example 1, it was changed to 1 mol / L oxalic acid. Fine particles (A2) A methanol dispersion was obtained.

  The average particle diameter, the uniformity of the particle diameter, and the acid radical in the particles were measured for the niobium oxide fine particles (A2), and the results are shown in Table 1. In addition, the stability, transparency, and refractive index of the particles were evaluated for the dispersion, and the results are shown in Table 1.

Preparation of Transparent Film Forming Coating Liquid (A2) A transparent film forming coating liquid (A2) was prepared in the same manner as in Example 1 except that the niobium oxide fine particles (A2) methanol dispersion was used.

Formation of lens (A2) with a transparent coating A lens (A2) with a transparent coating was formed in the same manner as in Example 1 using the coating solution (A2) for forming a transparent coating.

The same characteristics as in Example 1 were evaluated for the obtained lens (A2) with a transparent coating. The results are shown in Table 1.
[Example 3]
Preparation of Niobium Oxide Fine Particles (A3) Dispersion Niobium oxide fine particles (A3) in the same manner as in Example 1 except that 1 mol / L hydrochloric acid was used instead of the 1 mol / L acetic acid solution of Example 1. ) A methanol dispersion was obtained.

  The niobium oxide fine particles (A3) were measured for average particle size, uniformity of particle size, and acid radicals in the particles. The results are shown in Table 1. In addition, the stability, transparency, and refractive index of the particles were evaluated for the dispersion, and the results are shown in Table 1.

Preparation of Transparent Film Forming Coating Liquid (A3) A transparent film forming coating liquid (A3) was prepared in the same manner as in Example 1 except that the niobium oxide fine particles (A3) methanol dispersion was used.

Formation of lens (A3) with a transparent coating A lens (A3) with a transparent coating was formed in the same manner as in Example 1 using the coating solution (A3) for forming a transparent coating.

About the obtained lens (A3) with a transparent coating, the characteristic similar to Example 1 was evaluated. The results are shown in Table 1.
[Example 4]
Preparation of Niobium Oxide Fine Particle (A4) Dispersion Niobium Oxide Fine Particle (A1) Obtained in Example 1 1000 g of methanol dispersion and pure water 1000
g was placed in a reaction vessel, heated to 63 ° C., and 2 liters of a mixed solution of tetraethoxysilane and methanol (weight ratio 153/1000) was gradually added while stirring. After completion of the addition, the temperature of the solution is further maintained at 63 ° C. for aging, and then the solvent is replaced with methanol and concentrated, and the surface is modified with tetraethoxysilane having a solid concentration of 30.5% by weight. Fine particles (A4) A methanol dispersion was obtained.

Niobium Oxide Fine Particles (A4) The stability of the methanol dispersion, transparency, and refractive index of the particles were evaluated, and the results are shown in Table 1.
Preparation of Transparent Film Forming Coating Liquid (A4) A transparent film forming coating liquid (A4) was prepared in the same manner as in Example 1 except that the niobium oxide fine particles (A4) methanol dispersion was used.

Formation of lens (A4) with a transparent coating A lens (A4) with a transparent coating was formed in the same manner as in Example 1 using the coating solution (A4) for forming a transparent coating.

About the obtained lens (A4) with a transparent coating, the characteristic similar to Example 1 was evaluated. The results are shown in Table 1.
[Example 5]
Preparation of Niobium Oxide Fine Particle (A5) Dispersion Niobium Oxidation Surface-Modified with Methyltrimethoxysilane as in Example 4 except that tetraethoxysilane in Example 4 was replaced with methyltrimethoxysilane Fine particles (A5)
A methanol dispersion was obtained.

Niobium oxide fine particles (A5) Stability, transparency, and refractive index of the methanol dispersion were evaluated, and the results are shown in Table 1.
Preparation of Transparent Film Forming Coating Liquid (A5) A transparent film forming coating liquid (A5) was prepared in the same manner as in Example 1 except that the niobium oxide fine particles (A5) methanol dispersion was used.

Formation of lens (A5) with a transparent coating A lens (A5) with a transparent coating was formed in the same manner as in Example 1 using the coating solution (A5) for forming a transparent coating.

For the obtained lens with transparent coating (A5), the same characteristics as in Example 1 were evaluated. The results are shown in Table 1.
[Example 6]
Preparation of Niobium Oxide Fine Particle (A6) Dispersion γ-Glycidoxypropyltriethoxy in the same manner as in Example 4 except that tetraethoxysilane in Example 4 was replaced with γ-glycidoxypropyltriethoxysilane. Niobium oxide fine particles (A6) methanol-dispersed with silane surface modification were obtained.

Niobium Oxide Fine Particles (A6) Stability, transparency, and refractive index of the methanol dispersion were evaluated. The results are shown in Table 1.
Preparation of Transparent Film Forming Coating Liquid (A6) A transparent film forming coating liquid (A6) was prepared in the same manner as in Example 1 except that the niobium oxide fine particles (A6) methanol dispersion was used.

Formation of lens (A6) with a transparent coating A lens (A6) with a transparent coating was formed in the same manner as in Example 1 using the coating solution (A6) for forming a transparent coating.

For the obtained lens (A6) with a transparent coating, the same characteristics as in Example 1 were evaluated. The results are shown in Table 1.
[Example 7]
Preparation of Niobium Oxide Fine Particle (A7) Dispersion 706.91 g of niobium pentafluoride was dissolved in water, and 4.69 L of aqueous ammonia having a concentration of 15% by weight was added thereto over 40 minutes. This was filtered and washed to obtain 2000 g of niobic acid gel. The solid content concentration of this gel was 25.0% by weight in terms of Nb ₂ O ₅ .

After adding 33540 g of water to 1300 g of the resulting niobic acid gel and stirring sufficiently, 3000 g of 35% by weight hydrogen peroxide solution was added and dissolved by heating at 80 ° C. for 2 hours. Water was added to the obtained solution to adjust the concentration to 0.5% by weight in terms of Nb ₂ O ₅ , and then hydrothermal treatment was performed at 200 ° C. for 18 hours in an autoclave.

Next, this was concentrated to obtain 3500 g of an aqueous dispersion of niobium oxide fine particles (A7) having a concentration of 10% by weight in terms of Nb ₂ O ₅ .
Next, a part of the aqueous dispersion of niobium-based oxide fine particles (A7) is substituted with methanol for the dispersion medium and concentrated to give a niobium-based oxide fine particles (A7) methanol dispersion having a solid concentration of 20% by weight. Got.

  The niobium oxide fine particles (A7) were measured for average particle size, uniformity of particle size, and acid radicals in the particles. The results are shown in Table 1. In addition, the stability, transparency, and refractive index of the particles were evaluated for the dispersion, and the results are shown in Table 1.

Preparation of Transparent Film Forming Coating Liquid (A7) A transparent film forming coating liquid (A7) was prepared in the same manner as in Example 1 except that the niobium oxide fine particles (A7) methanol dispersion was used.

Formation of lens (A7) with a transparent film A lens (A7) with a transparent film was formed in the same manner as in Example 1 using the coating liquid (A7) for forming a transparent film.

The same characteristics as in Example 1 were evaluated for the obtained lens with transparent coating (A7). The results are shown in Table 1.
[Example 8]
Preparation of Niobium Oxide Fine Particle (A8) Dispersion The surface was modified with tetraethoxysilane in the same manner as in Example 4 except that the methanol-dispersed niobium oxide fine particle (A7) dispersion obtained in Example 7 was used. Niobium oxide fine particles (A8) A methanol dispersion was obtained.

Niobium Oxide Fine Particles (A8) Stability, transparency, and refractive index of the particles were evaluated for the methanol dispersion, and the results are shown in Table 1.
Preparation of Transparent Film Forming Coating Liquid (A8) A transparent film forming coating liquid (A8) was prepared in the same manner as in Example 1 except that the niobium oxide fine particles (A8) methanol dispersion was used.

Formation of lens (A8) with a transparent film A lens (A8) with a transparent film was formed in the same manner as in Example 1 using the coating liquid (A8) for forming a transparent film.

The same characteristics as in Example 1 were evaluated for the obtained lens with transparent coating (A8). The results are shown in Table 1.
[Example 9]
Preparation of Niobium Oxide Fine Particle (A9) Dispersion Niobium pentachloride was hydrolyzed with water, filtered and washed to obtain 2780 g of a niobic acid gel. The solid content concentration of this gel was 22.7% by weight in terms of Nb ₂ O ₅ . This niobic acid gel is weighed to 500 g in terms of Nb ₂ O ₅ , placed in a 10 L beaker, further charged with 1800 g of 35% by weight hydrogen peroxide, heated with stirring, and heated at 70 ° C. for 2 Dissolved for hours. Next, 2000 g of water was added thereto, heated at 70 ° C. for 1 hour, water was added again to obtain a 1% by weight solution in terms of Nb ₂ O ₅ concentration, and this was placed in an autoclave and subjected to hydrothermal treatment at 220 ° C. for 15 hours. .

Next, this was concentrated to obtain 500 g of an aqueous dispersion of niobium oxide fine particles (A9) having a concentration of 10% by weight in terms of Nb ₂ O ₅ .
Next, a part of the aqueous dispersion of niobium oxide fine particles (A9) is substituted with methanol for the water in the dispersion medium and concentrated to give a niobium oxide fine particles (A9) methanol dispersion with a solid concentration of 20% by weight. Got.

  The niobium oxide fine particles (A9) were measured for average particle size, uniformity of particle size, and acid radicals in the particles. The results are shown in Table 1. Further, the stability, transparency, and refractive index of the particles were evaluated for each dispersion, and the results are shown in Table 1.

Preparation of Transparent Film Forming Coating Liquid (A9) A transparent film forming coating liquid (A9) was prepared in the same manner as in Example 1 except that the niobium oxide fine particles (A9) methanol dispersion was used.

Formation of lens with transparent coating (A9) A transparent coating-coated lens (A9) was formed in the same manner as in Example 1 using the coating solution for forming a transparent coating (A9).

About the obtained lens (A9) with a transparent coating, the characteristic similar to Example 1 was evaluated. The results are shown in Table 1.
[Example 10]
Preparation of Niobium Oxide Fine Particle (A10) Dispersion Niobium pentachloride was hydrolyzed with water, filtered and washed to obtain 2780 g of a niobic acid gel.
The solid content concentration of this gel was 22.7% by weight in terms of Nb ₂ O ₅ . This niobic acid gel is weighed to 500 g in terms of Nb ₂ O ₅ , placed in a 50 L container containing 22797 g of water, further charged with 5714 g of 35% by weight hydrogen peroxide, and heated with stirring. It melt | dissolved at 70 degreeC for 2 hours. Subsequently, 19286 g of water was added thereto to make a 1% by weight solution in terms of Nb ₂ O ₅ concentration. Subsequently, 333 g of silica sol having an average particle diameter of 7 nm as core particles and a SiO ₂ concentration of 15% by weight and 4662 g of water were mixed, placed in an autoclave, and hydrothermally treated at 220 ° C. for 15 hours.

Subsequently, this was concentrated to obtain 5500 g of a niobium oxide fine particle (A10) aqueous dispersion having a concentration of 10% by weight in terms of (Nb ₂ O ₅ + SiO ₂ ).
Next, a part of the aqueous dispersion of niobium-based oxide fine particles (A10) is replaced with methanol as the dispersion medium and concentrated to obtain a composite oxide fine particle (A10) methanol dispersion with a solid content concentration of 20% by weight. Obtained.

With respect to the composite oxide fine particles (A10), the average particle diameter, the uniformity of the particle diameter, and the acid radical in the particles were measured, and the results are shown in Table 1. In addition, the stability, transparency, and refractive index of the particles were evaluated for the dispersion, and the results are shown in Table 1.

Preparation of coating liquid for forming transparent film (A10) Niobium oxide fine particles (A10) In the same manner as in Example 1 except that a methanol dispersion was used.
A coating solution for forming a transparent film (A10) was prepared.

Formation of lens with transparent coating (A10) A transparent coating-coated lens (A10) was formed in the same manner as in Example 1 using the coating solution for forming a transparent coating (A10).

For the obtained lens with transparent coating (A10), the same characteristics as in Example 1 were evaluated. The results are shown in Table 1.
[Example 11]
Preparation of Niobium Oxide Fine Particle (A11) Dispersion Niobium pentachloride and ferric chloride were hydrolyzed with water, washed by filtration, and 2780 g of a mixed gel of niobic acid and iron hydroxide was obtained. The solid content concentration of this gel was 23.5% by weight in terms of (Nb ₂ O ₅ + Fe ₂ O ₃ ). This mixed gel of niobic acid and iron hydroxide was weighed so as to be 500 g in terms of (Nb ₂ O ₅ + Fe ₂ O ₃ ), put into a 50 L container containing 22872 g of water, and an excess of 35% by weight concentration. 5714 g of hydrogen oxide water was added, heated with stirring, dissolved at 70 ° C. for 2 hours, and then 19286 g of water was added thereto to give a 1% by weight solution in terms of (Nb ₂ O ₅ + Fe ₂ O ₃ ).

Subsequently, 333 g of silica sol having an average particle diameter of 7 nm as core particles and a SiO ₂ concentration of 15% by weight and 4662 g of water were mixed, and this was placed in an autoclave and hydrothermally treated at 220 ° C. for 15 hours.

Next, this was concentrated to obtain 5238 g of an aqueous dispersion of niobium oxide fine particles (A11) having a concentration of 10% by weight in terms of (Nb ₂ O ₅ + Fe ₂ O ₃ + SiO ₂ ).
Next, a part of the aqueous dispersion of niobium-based oxide fine particles (A11) is substituted with methanol as the dispersion medium and concentrated to give a niobium-based oxide fine particles (A11) methanol dispersion having a solid concentration of 20% by weight. Got.

The average particle diameter, the uniformity of the particle diameter, and the acid radical in the particles were measured for the niobium oxide fine particles (A11), and the results are shown in Table 1. In addition, the stability, transparency, and refractive index of the particles were evaluated for the dispersion, and the results are shown in Table 1.

Preparation of Transparent Film Forming Coating Solution (A11) Niobium Oxide Fine Particles (A11) Except for using methanol dispersion,
A coating solution for forming a transparent film (A11) was prepared.

Formation of lens with transparent film (A11) A transparent film-coated lens (A11) was formed in the same manner as in Example 1 using the coating liquid for forming a transparent film (A11).

About the obtained lens (A11) with a transparent coating, the characteristic similar to Example 1 was evaluated. The results are shown in Table 1.
[Example 12]
Preparation of niobium oxide fine particle (A12) dispersion
Preparation of core particles In the same manner as in Example 3, niobium-based oxide fine particles (A3) in water dispersion for core particles were obtained. The average particle diameter of the niobium-based oxide fine particles was 20 nm.
Preparation of Zirconium Compound Solution A 15% aqueous ammonia solution was added to an aqueous solution containing 2% by weight of ZrO ₂ with 171 g of zirconium oxychloride added to 128 g of water to obtain a slurry having a pH of 8.5. The slurry was filtered and washed to obtain a 10% by weight cake as ZrO ₂ . After adding 3.08 kg of water to 60 g of this cake and adding KOH aqueous solution to make it alkaline, 120 g of hydrogen peroxide was added thereto and heated to give 299 g of 2 wt% zirconium hydrogen peroxide-dissolved aqueous solution as ZrO _2. Prepared.
Preparation of Silicic Acid Solution A commercially available water glass was diluted with water and then dealkalized with a cation exchange resin to prepare 926 g of a silicic acid solution having a SiO ₂ concentration of 2% by weight.

  14 kg of water was added to 3500 g of the niobium oxide fine particle (A3) dispersion for core particles prepared above to obtain a solid concentration of 2% by weight, and then heated to 90 ° C., and 299 g of a hydrogen peroxide-dissolved aqueous solution of zirconium and silica. 926 g of acid solution was mixed. Next, this mixed solution was hydrothermally treated at 200 ° C. for 18 hours in an autoclave, and then concentrated to convert the transparent niobium oxide particles having a solid content concentration of 10% by weight into light milky white composite oxide composed of silicon oxide and zirconium oxide. An aqueous dispersion of niobium oxide fine particles (A12) coated with a product was obtained.

Next, a part of the aqueous dispersion of niobium-based oxide fine particles (A12) is substituted with methanol as the dispersion medium and concentrated to give a niobium-based oxide fine particles (A12) methanol dispersion having a solid concentration of 20% by weight. Got.

The niobium-based oxide fine particles (A12) were measured for average particle size, uniformity of particle size, and acid radicals in the particles. The results are shown in Table 1. Further, the stability, transparency, and refractive index of the particles were evaluated for the dispersion, and the results are shown in Table 1.

Preparation of coating liquid for forming transparent film (A12) Niobium oxide fine particles (A12) In the same manner as in Example 1 except that a methanol dispersion was used.
A coating solution for forming a transparent film (A12) was prepared.

Formation of lens (A12) with a transparent coating A lens (A12) with a transparent coating was formed in the same manner as in Example 1 using the coating solution (A12) for forming a transparent coating.

The same characteristics as in Example 1 were evaluated for the obtained lens with transparent coating (A12). The results are shown in Table 1.
[Example 13]
Preparation of niobium oxide fine particle (A13) dispersion
Preparation of core particles Titanium tetrachloride was hydrolyzed with water, filtered and washed to obtain 2780 g of titanic acid gel. The solid content concentration of this gel was 9.4% by weight in terms of TiO ₂ . This titanic acid gel is weighed to 500 g in terms of TiO 2, placed in a 50 L container containing 22882 g of water, and further 5714 g of hydrogen peroxide solution having a concentration of 35% by weight, and heated with stirring at 90 ° C. Dissolved for 2 hours. Subsequently, 19286 g of water was added thereto to obtain a 0.5% by weight solution in terms of TiO ₂ concentration. This was put into an autoclave and hydrothermally treated at 150 ° C. for 15 hours. Subsequently, this was concentrated to obtain 5238 g of a titanium oxide fine particle dispersion having a concentration of 1.5% by weight in terms of TiO ₂ and an average particle diameter of 12 nm.

Preparation of niobium compound solution Niobium pentachloride was hydrolyzed with water, filtered and washed to obtain 2780 g of a gel of niobic acid. The solid content concentration of this gel was 22.7% by weight in terms of Nb ₂ O ₅ . This niobic acid gel is weighed to 500 g in terms of Nb ₂ O ₅ , placed in a 50 L container containing 22797 g of water, further charged with 5714 g of 35% by weight hydrogen peroxide, and heated with stirring. It melt | dissolved at 70 degreeC for 2 hours. Next, 19286 g of water was added thereto to obtain a 1% by weight niobium hydrogen peroxide-dissolved aqueous solution in terms of Nb ₂ O ₅ concentration.
Preparation of Zirconium Compound Solution A 15% aqueous ammonia solution was added to an aqueous solution having a ZrO ₂ concentration of 2% by weight with 1710 g of zirconium oxychloride added to 1280 g of water to obtain a slurry having a pH of 8.5. The slurry was washed and filtered to give 10% by weight of the cake as ZrO _2. After adding 30.8 kg of water to 600 g of this cake and adding KOH aqueous solution to make it alkaline, 1200 g of hydrogen peroxide was added and heated, and 2990 g of hydrogen peroxide-dissolved aqueous solution of 2 wt% zirconium as ZrO ₂ was added. Prepared.

5238 g of the titanium oxide fine particle dispersion for core particles prepared above is heated to 90 ° C. and mixed with a hydrogen peroxide-dissolved aqueous solution of niobium and 2990 g of a hydrogen peroxide-dissolved aqueous solution of zirconium, and this mixture is then placed in an autoclave. After hydrothermal treatment at 180 ° C. for 18 hours, niobium-based oxidation in which transparent titanium oxide fine particles with a concentration of 10% by weight and solid milk concentration are coated with a composite oxide composed of niobium oxide and zirconium oxide. Fine particle (A13) aqueous dispersion was obtained.

Next, a part of the aqueous dispersion of niobium-based oxide fine particles (A13) is substituted with methanol as the dispersion medium and concentrated to give a niobium-based oxide fine particles (A13) methanol dispersion having a solid concentration of 20% by weight. Got.

The niobium oxide fine particles (A13) were measured for average particle size, uniformity of particle size, and acid radicals in the particles. The results are shown in Table 1. Further, the stability, transparency, and refractive index of the particles were evaluated for the dispersion, and the results are shown in Table 1.

Preparation of coating liquid for forming transparent film (A13) Niobium oxide fine particles (A13) In the same manner as in Example 1 except that the methanol dispersion was used.
A coating solution for forming a transparent film (A13) was prepared.

Formation of lens with transparent coating (A13) A lens with transparent coating (A13) was formed in the same manner as in Example 1 using the coating solution for transparent coating formation (A13).

For the obtained lens with transparent coating (A13), the same characteristics as in Example 1 were evaluated. The results are shown in Table 1.
[Example 14]
Nb based oxide particles (A14) were mixed to prepare a concentration 35.3% by weight of the KNbO ₃ solution 1917g of water 23083g of the dispersion, the concentration of 2.71 wt% of KNbO ₃ solution, to which the 1 mol / L acetic acid Added and neutralized. The pH at this time was 5.5. This was filtered and washed with distilled water to obtain 1990 g of niobic acid gel. The solid content concentration of this gel was 24.01% by weight in terms of Nb ₂ O ₅ .

Preparation of seed particle dispersion Water was added to a portion of 498 g of niobic acid gel to give a niobic acid gel dispersion having a concentration of 2% by weight in terms of Nb ₂ O ₅ , and this was irradiated with ultrasonic waves for 20 minutes. 5978 g of a seed particle dispersion was prepared. The average particle size of the seed particles was about 1 nm.

35823 g of water was added to 1492 g of the remaining niobic acid gel, and after sufficient stirring, 6000 g of 35% by weight hydrogen peroxide water was added and dissolved by heating at 80 ° C. for 2 hours. Water was added to the resulting solution to adjust the concentration to 0.5% by weight in terms of Nb ₂ O ₅ , 5978 g of seed particle dispersion was added thereto, and hydrothermal treatment was performed at 180 ° C. for 18 hours in an autoclave.

Subsequently, this was concentrated to obtain 3500 g of an aqueous dispersion of niobium oxide fine particles (A14) having a concentration of 10% by weight in terms of Nb ₂ O ₅ .
Next, a part of the aqueous dispersion of niobium-based oxide fine particles (A14) is substituted with methanol for the water in the dispersion medium and concentrated to give a niobium-based oxide fine particles (A14) methanol dispersion having a solid concentration of 20% by weight. Got.

The niobium oxide fine particles (A14) were measured for average particle size, uniformity of particle size, and acid radicals in the particles. The results are shown in Table 1. Further, the stability, transparency, and refractive index of the particles were evaluated for each dispersion, and the results are shown in Table 1.

Preparation of Transparent Film Forming Coating Solution (A14) Niobium Oxide Fine Particles (A14) Except for using methanol dispersion,
A coating solution for forming a transparent film (A14) was prepared.

Formation of lens with transparent film (A14) A lens with transparent film (A14) was formed in the same manner as in Example 1 using the coating liquid for forming a transparent film (A14).

The same characteristics as in Example 1 were evaluated for the obtained lens with transparent coating (A14). The results are shown in Table 1.
[Comparative Example 1]
Preparation of oxide fine particle (R1) dispersion
Preparation of titanium oxide-containing core particle dispersion
While stirring 25 kg of titanium sulfate aqueous solution having a concentration of 0.4% by weight converted to TiO ₂ , ammonia water having a concentration of 15% by weight was gradually added thereto for hydrolysis to obtain a white slurry liquid having a pH of 8.5. It was. The slurry was filtered and then washed to obtain 11.11 kg of a hydrous titanate gel cake having a solid content concentration of 9% by weight.

After adding 12.12 kg of hydrogen peroxide water having a concentration of 33% by weight and 26.8 kg of water to 11.11 kg of the cake, the cake was heated at 80 ° C. for 5 hours to obtain 2.0% by weight of titanium peroxide as TiO _2. The acid aqueous solution was transparent yellowish brown and had a pH of 8.1. Next, 666.6 g of silica sol having an average particle diameter of 7 nm and a SiO ₂ concentration of 15% by weight, 50.03 kg of the above titanic acid aqueous solution, and 49.34 kg of pure water were mixed, and the mixture was autoclaved at 200 ° C., 96 ° C. Heated for hours. The colloidal solution obtained after heating was concentrated to obtain 11.0 kg of a titanium oxide-containing core particle dispersion having a solid content of 10% by weight.
Zirconium peroxide solution 526 g of zirconium oxychloride dissolved in 947 g of water was hydrolyzed by adding 15% ammonia water to an aqueous solution of zirconium oxychloride having a concentration of 2% by weight of ZrO ₂ to obtain a slurry of pH 8.5. It was. This slurry was filtered and washed to prepare 610 g of a hydrogen peroxide solution of zirconium having a concentration of 2% by weight as ZrO ₂ .
Preparation of Silicic Acid Solution A commercially available water glass was diluted with water and then dealkalized with a cation exchange resin to prepare 1890 g of a silicic acid solution having a SiO ₂ concentration of 2% by weight.

  28.56 kg of water was added to 7.14 kg of the titanium oxide-containing core particle-dispersed sol prepared above to obtain a solid concentration of 2% by weight, and then heated to 90 ° C., followed by 610 g of zirconium hydrogen peroxide solution and silicic acid solution. 1890 g was mixed. The mixture was then heat-treated at 200 ° C. for 18 hours in an autoclave, and then concentrated by an ultrafiltration membrane method, and transparent titanium oxide-containing core particles having a solid milk concentration of 10% by weight were formed into silicon oxide. An oxide fine particle (R1) aqueous dispersion composed of titanium oxide, silica and zirconium oxide having a coating layer composed of and zirconium oxide was obtained.

  Next, water in the dispersion medium was replaced with methanol for one minute of the oxide fine particle (R1) aqueous dispersion, and concentrated to a solid content concentration of 20% by weight to prepare an oxide fine particle (R1) methanol dispersion. .

  For the oxide fine particles (R1), the average particle size, the uniformity of the particle size, and the acid radicals in the particles were measured, and the results are shown in Table 1. In addition, the stability, transparency, and refractive index of the particles were evaluated for the dispersion, and the results are shown in Table 1.

Preparation of coating liquid for transparent film formation (R1) A coating liquid for transparent film formation (R1) was prepared in the same manner as in Example 1 except that the oxide fine particle (R1) methanol dispersion was used.

Formation of lens (R1) with a transparent film A lens (R1) with a transparent film was formed in the same manner as in Example 1 using the coating liquid (R1) for forming a transparent film.

About the obtained lens (R1) with a transparent coating, the characteristic similar to Example 1 was evaluated. The results are shown in Table 1.
[Comparative Example 2]
Preparation of oxide fine particle (R2) dispersion A titanium oxide-containing core particle dispersion having a solid concentration of 10% by weight was prepared in the same manner as in Comparative Example 1. Next, water for the dispersion medium was replaced with methanol for one minute of the titanium oxide-containing core particle dispersion, and concentrated to a solid content concentration of 20% by weight to prepare an oxide fine particle (R2) methanol dispersion.

  For the oxide fine particles (R2), the average particle size, the uniformity of the particle size, and the acid radicals in the particles were measured, and the results are shown in Table 1. In addition, the stability, transparency, and refractive index of the particles were evaluated for the dispersion, and the results are shown in Table 1.

Preparation of coating liquid for forming transparent film (R2) A coating liquid for forming a transparent film (R2) was prepared in the same manner as in Example 1 except that the oxide fine particle (R2) methanol dispersion was used.

Formation of lens (R2) with a transparent film A lens (R2) with a transparent film was formed in the same manner as in Example 1 using the coating liquid (R2) for forming a transparent film.

About the obtained lens (R2) with a transparent coating, the same characteristic as Example 1 was evaluated. The results are shown in Table 1.
[Comparative Example 3]
Preparation of oxide fine particle (R3) dispersion 1000 g of oxide fine particle (R1) methanol dispersion obtained in the same manner as in Comparative Example 1 and 1000 g of pure water were placed in a reaction vessel and heated to 63 ° C. 2 liters of a mixture of glycidoxypropyltriethoxysilane and methanol (weight ratio 153/1000) was gradually added. After completion of the addition, the solution was further aged by maintaining the temperature at 63 ° C., then solvent-replaced with methanol and concentrated, and surface modification with γ-glycidoxypropyltriethoxysilane having a solid content concentration of 30.5% by weight. An oxide fine particle (R3) methanol dispersion was obtained.

The stability of the oxide microparticle (R3) methanol dispersion, transparency, and refractive index of the particles were evaluated, and the results are shown in Table 1.
Preparation of Transparent Coating Forming Coating Solution (R3) A transparent coating forming coating solution (R3) was prepared in the same manner as in Example 1 except that the oxide fine particle (R3) methanol dispersion was used.

Formation of lens (R3) with a transparent film A lens (R3) with a transparent film was formed in the same manner as in Example 1 using the coating liquid (R3) for forming a transparent film.

About the obtained lens (R3) with a transparent film, the same characteristics as Example 1 were evaluated. The results are shown in Table 1.
[Comparative Example 4]
Preparation of Oxide Fine Particle (R4) Dispersion 1000 g of Oxide Fine Particle (R2) Methanol Dispersion obtained in the same manner as Comparative Example 2 and 1000 g of pure water were placed in a reaction vessel and heated to 63 ° C. 2 liters of a mixture of glycidoxypropyltriethoxysilane and methanol (weight ratio 153/1000) was gradually added. After completion of the addition, the solution was further aged by maintaining the temperature at 63 ° C., then solvent-replaced with methanol and concentrated, and surface modification with γ-glycidoxypropyltriethoxysilane having a solid content concentration of 30.5% by weight. An oxide fine particle (R4) methanol dispersion was obtained.

The stability of the oxide microparticle (R4) methanol dispersion, transparency, and refractive index of the particles were evaluated, and the results are shown in Table 1.
Preparation of coating liquid for forming transparent film (R4) A coating liquid for forming a transparent film (R4) was prepared in the same manner as in Example 1 except that the oxide fine particle (R4) methanol dispersion was used.

Formation of lens (R4) with a transparent coating A lens (R4) with a transparent coating was formed in the same manner as in Example 1 using the coating solution (R4) for forming a transparent coating.

  The same characteristics as in Example 1 were evaluated for the obtained lens (R4) with a transparent coating. The results are shown in Table 1.

Claims (4)

Containing niobium-based oxide fine particles and a matrix-forming component,
The niobium-based oxide fine particles have a core-shell structure in which core particles are covered with a shell,
(i) the core particle (core) is niobium oxide fine particles,
Whether the shell is made of one or more oxides selected from oxides of Nb, Fe, Si, Ti, Zr,
Or
(ii) The core particle (core) is one or more kinds of oxide fine particles selected from Si, Zr, and Ti,
The shell is made of Nb oxide or one or more oxides selected from Nb oxide and an oxide of Fe, Si, Zr, Ti,
A coating liquid for forming a transparent film for an optical lens, wherein the matrix-forming component is a hydrolyzable organosilicon compound and / or a hydrolyzate of a hydrolyzable organosilicon compound. 2. The coating liquid for forming a transparent film for an optical lens according to claim 1, wherein the niobium-based oxide fine particles have an average particle diameter in the range of 2 to 60 nm. 3. The coating solution for forming a transparent film for an optical lens according to claim 1, wherein the niobium-based oxide fine particles have a surface treated with an organosilicon compound or an amine-based compound. A substrate with a transparent coating, comprising a transparent coating formed using the transparent coating solution for an optical lens according to any one of claims 1 to 3 on the surface of the substrate.