Coating composition

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention comprises a coating composition that can be used as a hard coating agent, an ultraviolet absorbing coating agent, an antireflection coating agent, etc. for optical components, a sol contained in the coating composition, and a coating with the coating composition. For example, the present invention relates to optical components such as spectacle lenses, camera lenses, optical filters attached to display of word processors, and window glasses of automobiles.

【0002】

[Conventional technology]

Titanium oxide is a substance having the highest refractive index among various metal oxides, and by applying it as a sol to the surface of a transparent base material such as glass or plastic to form a coating, the surface hardness of glass or plastic can be determined. It is known that the ultraviolet absorption characteristics, antireflection characteristics, etc. can be improved. Examples of the coating film containing titanium oxide include a coating film containing titanium oxide particles and an organic silicon compound (Japanese Patent Laid-Open No. 63-225635), composite oxide fine particles of titanium oxide and cerium oxide, and organic silicon. Hard coat films made of compounds (Japanese Patent Laid-Open No. 2-264902), hard coat films made of composite oxide fine particles of titanium oxide and iron oxide and organic silicon compounds (Japanese Patent Laid-Open No. 5-2102), etc. Are known. In each of these, a coating film is formed by a mixture of titanium oxide and a specific compound, and the characteristics of the coating film are improved.

【0003】

However, since titanium oxide itself is a photocatalyst, there is a problem that the organic substance is decomposed by irradiation with ultraviolet light when it is used in contact with or mixed with the organic substance. For example, the coating produced by the method of Japanese Patent Application Laid-Open No. 63-225635 has inferior light resistance, and has a problem that discoloration and deterioration of the film occur when exposed to sunlight, especially ultraviolet rays for a long period of time. ..

【0004】

In order to solve such a problem, attempts have been made to reduce the photocatalytic activity of titanium oxide particles contained in the coating agent. For example, as a surface treatment for the purpose of improving light resistance, it is reported that titanium oxide is coated with aluminum oxide-titanium oxide, aluminum oxide-silicon oxide, etc., and the catalytically active points are sealed to improve light resistance (AWEvans, Paint Technology, Vol. 26, No. 16, 1962). The surface of the titanium oxide particles disclosed in this report is densely coated with a coating material, and it is believed that this coating inhibits the catalytic action of titanium oxide. However, since the absorption of the coating substance near the absorption edge wavelength of titanium oxide is small, it cannot be said that the light resistance of the coating film is sufficient when the composite particles are irradiated with ultraviolet light near the absorption edge of titanium oxide. .. Japanese Patent Application Laid-Open No. 4-10918 discloses titanium oxide fine particles coated with cerium oxide fine particles, but this publication does not teach or suggest the light resistance of a coating film containing titanium oxide fine particles.

【0005】

[Problems to be Solved by the Invention]

The present inventor has found that a coating film containing titanium oxide fine particles coated with cerium oxide fine particles exhibits excellent light resistance, but at the same time, in order to form a coating film having a high refractive index, the composite particles are used. It has been found that when a large amount of coating is applied to the containing gel, the problem that the coating film is colored yellow occurs. Further, the cerium oxide-containing coating film described in JP-A-2-264902 also has a problem of being colored yellow, and the iron oxide-containing coating film described in JP-A-5-2102 is red. Since it is colored brown, none of them can be used as a colorless and transparent hard coat. In particular, in spectacle lenses, those colored yellow tend to be disliked by consumers, and the degree of coloring of the lenses colored yellow is reduced by a method called bluing. Therefore, a spectacle lens having such a colored coating film, particularly a yellow-colored coating film, has a significantly inferior value as a product.

【0006】

Therefore, the present invention imparts excellent refraction and light resistance to the formed coating film by reducing the photocatalytic activity without losing the high refraction characteristics of titanium oxide, and even when a large amount of coating is applied. An object of the present invention is to provide a titanium oxide-containing coating composition capable of forming a colorless and transparent coating film in the visible region. Another object of the present invention is to provide a titanium oxide-containing sol contained in a coating composition having the above-mentioned properties.

【0007】

[Means for solving problems]

As a result of diligent efforts to solve the above problems, the present inventor has sufficient absorption characteristics near the absorption edge wavelength of titanium oxide, and zinc oxide is extremely suitable as a colorless and transparent coating substance in the visible region. I found that. Further, when the titanium oxide particles are coated with zinc oxide, the photocatalytic property of titanium oxide can be sufficiently suppressed with a very small amount of coating, so that the coating film formed by the coating agent containing the titanium oxide particles is made of titanium oxide. It was found that it is colorless and transparent in the visible range while maintaining high refraction, and is extremely excellent in light resistance. The present invention has been completed based on the above findings.

【0008】

That is, the present invention provides composite titanium oxide particles characterized in that a zinc oxide coating is provided on the surface of the titanium oxide particles. According to the aspect of the present invention, the composite titanium oxide particles having a particle size of the titanium oxide particles of 5 to 100 nm and the particle size of the titanium oxide composite particles of 10 to 120 nm; and the composite titanium oxide particles. A sol containing is provided. In addition, (a) a step of producing a gel in which titanium oxide particles are dispersed in alcohols by hydrolysis of a titanium alkoxide or a titanium salt solution, (b) a step of adding a zinc compound to the gel, and (c) By adding a base to the mixture obtained in the above step (b) or performing a hydrolysis reaction, zinc oxide is precipitated on the surface of the titanium oxide particles to form a zinc oxide coating on the surface of the titanium oxide particles. Provided is a method for producing the above sol, which comprises a step.

【0009】

Further, according to the present invention, the coating composition comprises (a) the composite titanium oxide particles according to claim 1, and (b) the formula: (R).¹) _a(R²)_{b b}Si (OR³)_4-ab(In the formula, R¹, R²Represents a functional group having an alkyl group, an alkenyl group, an allyl group, a halogen group, an epoxy group, an amino group, a mercapto group, a methacryloxy group, a cyano group, an aryl group, or an acyl group, and represents R.³Represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and a and b are compounds represented by (integer of 0 to 2) and / or a film-forming substance which is a hydrolyzate thereof. The article; and a coating composition containing the sol containing the composite titanium oxide particles and the film-forming substance described above are provided. Further, according to the present invention, there is provided an optical component having a coating film formed by applying and curing the above coating composition. According to an aspect of the present invention, the optical component having a colorless coating film in the visible region is provided.

【0010】

The composite titanium oxide particles of the present invention are characterized in that a zinc oxide coating is provided on the surface of the titanium oxide particles. For example, after producing a sol containing titanium oxide particles forming a core portion, the composite titanium oxide particles are coated. It can be produced by precipitating zinc oxide, which is a substance, on the surface of titanium oxide particles. The above method is a step of producing a gel in which titanium oxide particles are dispersed in alcohols by hydrolysis of a titanium alkoxide or a titanium salt solution, (b) a step of adding a zinc compound to the gel, and (c). By adding a base to the mixture obtained in the above step (b) or performing a hydrolysis reaction, zinc oxide is precipitated on the surface of the titanium oxide particles to form a zinc oxide coating on the surface of the titanium oxide particles. It includes steps.

【0011】

The sol containing the titanium oxide particles can be produced by, for example, hydrolysis of titanium alkoxide or hydrolysis of a titanium salt solution, but a commercially available titanium oxide sol may be used. The particle size of the titanium oxide particles contained in the above sol is preferably in the range of 5 to 100 nm. If the particle size is 5 nm or less, the sol may become unstable, and if it is 100 nm or more, the particle size may increase after coating with zinc oxide, and the transparency of the finally obtained sol may decrease.

【0012】

As a starting material for obtaining titanium oxide particles, for example, a titanium compound soluble in a solvent may be used. As the titanium alkoxide, for example, methoxide, ethoxyoxide, normal propoxide, isopropoxide, normal butoxide, isobutoxide and the like can be used, and as the titanium salt, for example, chloride, iodide, bromide, nitrate, sulfate, acetic acid and the like can be used. Salts, oxalates, citrates, tartrates and the like can be used. Examples of other titanium compounds include chelate compounds such as diisopropoxybisacetylacetonate titanium and diisopropoxybisethylacetacetate titanium, and acylates such as tri-n-butoxytitanium monostearate. Of these, a produced sol that is good for hydrolyzing titanium alkoxide is preferable because the titanium oxide particles have a fine particle size and a uniform particle size.

【0013】

Solvents used in the production of sol containing titanium oxide particles include water; alcohols such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, normal butyl alcohol, isobutyl alcohol; ethers such as tetrahydrofuran and diethyl ether; , Esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate; polyhydric alcohols such as ethylene glycol and glycerin; cellosolves such as ethyl cellosolve and cellosolve acetate. These solvents may be used alone or in combination of two or more. Generally, the titanium compound may be dissolved in these solvents so as to be 0.01 to 20% by weight to carry out the hydrolysis reaction.

【0014】

In the production of a sol containing titanium oxide particles, it is preferable to add a polymer dispersant because the stability of the sol is increased. As the polymer dispersant, for example, a cellulose derivative can be used, and examples thereof include hydroxypropyl cellulose, hydroxyethyl cellulose, ethyl cellulose, methyl cellulose, carboxymethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl ethyl cellulose, benzyl cellulose, acetyl cellulose, and nitrocellulose. , Cellulose phthalate acetate, cellulose butyrate acetate and the like. The polymer dispersant is preferably added before the titanium oxide is precipitated from the titanium compound, and should be added before the precipitated titanium oxide particles are fused or aggregated with each other.

【0015】

In order to coat the surface of the titanium oxide particles with zinc oxide used as a coating substance, a solution containing a zinc compound soluble in a solvent may be produced, and zinc oxide may be precipitated on the surface of the titanium oxide particles from the solution. Zinc compounds include salts such as chlorides, iodides, bromides, nitrates, sulfates, acetates, oxalates, citrates, tartrates; diisopropoxybisacetylacetonate and diisopropoxybisethylacetase. Chelates such as tart; alkoxides such as methoxydo, ethoxide, normal propoxide, isopropoxide, normal butoxide, isobutoxide, etc. can be mentioned, and among these zinc compounds, those soluble in the reaction solvent are appropriately selected. And use it. To produce a sol containing composite titanium oxide particles, a solution of a zinc compound is added to and mixed with the titanium oxide sol, and then a base is added to the mixture or a hydrolysis reaction is carried out to form an oxide on the surface of the titanium oxide particles. Zinc oxide may be precipitated.

【0016】

The composite titanium oxide particles produced as described above are those in which a zinc oxide coating is provided on the surface of the titanium oxide particles, and it is desirable that the particle size is generally in the range of 10 to 120 nm. If the particle size is 10 nm or less, the obtained sol may become unstable, and if it is 120 nm or more, the particle size may increase after covering with a coating material, and the transparency of the finally obtained sol may decrease. .. The lower the concentration of the zinc compound in the reaction solution, the finer the particle size of the composite titanium oxide particles can be obtained. However, the concentration of the zinc compound in the reaction solution can be determined by the solvent evaporation method or the ultrafiltration method depending on the application. It can be adjusted by any method such as. In general, it is preferable to use a zinc compound solution having a concentration of about 0.01% by weight to 10% by weight.

【0017】

According to the present invention, (a) the above composite titanium oxide particles, and (b) equation: (R).¹) _a(R²)_{b b}Si (OR³)_4-ab(In the formula, R¹, R²Represents a functional group having an alkyl group, an alkenyl group, an allyl group, a halogen group, an epoxy group, an amino group, a mercapto group, a methacryloxy group, a cyano group, an aryl group, or an acyl group, and represents R.³Is represented by hydrogen or an alkyl group having 1 to 4 carbon atoms, and a and b are integers of 0 to 2) to provide a coating composition containing a compound and / or a film-forming substance which is a hydrolyzate thereof. .. Generally, the coating composition is produced by mixing the sol containing the composite titanium oxide particles with a film forming agent.

【0018】

In the film forming agent represented by the above general formula, R¹And R²A functional group having adhesiveness to a substrate such as plastic is effective. OR³ The alkoxy group represented by is hydrolyzed by water to form a -Si-O-Si- bond and has an action of forming a film. R³When the number of carbon atoms in the film is 5 or more, the molecular weight of the alcohol produced by hydrolysis increases, which is not preferable because it may be difficult to remove the alcohol and the density of the film may be lowered. General formula R¹_aR²_{b b}Si (OR³)_4-abSpecific examples of the compounds represented by are tetramethylsilane, tetraethylsilane, tetra-n-propylsilane, tetraisopropylsilane, tetra-n-butylsilane, tetra-sec-butylsilane, tetra-t-butylsilane, dimethyldimethoxysilane, and the like. Diethyldiethoxysilane, di-n-propyldi-n-propoxysilane, diisopropyldiisopropoxysilane, di-n-butyldi-n-butyloxysilane, di-sec-butyldi-sec-butyloxysilane, [0019]

Di-t-butyldi-t-butyloxysilane, methyloctadecyldimethoxysilane, methyldodecyldiethoxysilane, methyloctadecyldiethoxysilane, n-octylmethyldimethoxysilane, n-octylmethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxy Silane, Methyltri-n-propoxysilane, Methyltriisopropoxysilane, Methyltri-n-butyroxysilane, Methyltri-sec-butyroxysilane, Methyltri-t-butyroxysilane, Ethyltrimethoxysilane, Ethyltriethoxysilane, Ethyltri-n-propoxysilane, Ethyltriisopropoxysilane, ethyltri-n-butyloxysilane, ethyltri-sec-butyroxysilane, ethyltri-t- Butyloxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, hexadecyltrimethoxysilane, n-octyltrimethoxysilane, n-dodecyltrimethoxysilane, n-octadecyltrimethoxysilane, n- Propyltriethoxysilane, isobutyltriethoxysilane, n-hexyltriethoxysilane, hexadecyltriethoxysilane, n-octyltriethoxysilane, n-dodecyltriethoxysilane, n-octadecyltriethoxysilane, diphenyldimethoxysilane, diphenyldi Ethoxysilane, dibenzyldimethoxysilane, [0020]

Dibenzyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, benzyltrimethoxysilane, benzyltriethoxysilane, 3-acetoxypropyltrimethoxysilane, 3-acetoxypropyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane Silane, 4-aminobutyltriethoxysilane, (aminoethylaminomethyl) phenetiltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-amino Propylmethyltrimethoxysilane, 6- (aminohexylaminopropyl) trimethoxysilane, p-aminophenyltrimethoxysilane, p-aminophenyltriethoxysilane, 3-aminopropyltrimethoxysilane, [0021] [0021]

3-Aminopropyltriethoxysilane, ω-aminoundecyltrimethoxysilane, aminotriethoxysilane, bis- (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 8-bromooctyltrimethoxysilane, bromophenyltri Methoxysilane, 3-bromopropyltrimethoxysilane, n-broltrimethoxysilane, 2-chloromethyltriethoxysilane, chloromethylmethyldiethoxysilane, chloromethylmethyldiisopropoxysilane, p- (chloromethyl) phenyltrimethoxy Silane, chloromethyltriethoxysilane, chlorophenyltriethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2- (4-chloroslophonylphenyl) ethyltri Methoxysilane, 2-cyanoethyltriethoxysilane, 2-cyanoethyltrimethoxysilane, cyanomethylphenetiltriethoxysilane, 3-cyanopropyltriethoxysilane, 2- (3-cyclohexenyl) ethyltrimethoxysilane, (cyclohexylaminomethyl) Methyldiethoxysilane, (3- Cyclopentadienylpropyl) triethoxysilane, [0022]

(N, N-diethyl-3-aminopropyl) trimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, (3-glycidoxypropyl) methyldiethoxysilane, 3-glycidoxypropyl Triethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 1,2,3,4,7,7-hexachloro-6-methyldiethoxylyl-2-norbornene, 1 , 2,3,4,7,7-Hexachloro-6-triethoxysilyl-2-norbornene, 3-iodopropyltrimethoxysilane, 3-isocyanuppropyltriethoxysilane, (mercaptomethyl) methyldiethoxysilane, 3- Mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, [0023]

3-methacryloxypropyltriethoxysilane, methyl [2- (3-trimethoxysilylpropylamino) ethylamino] -3-propionate, 7-octynyltrimethoxysilane, RN-α-phenethyl-N ́-triethoxysilyl Propylurea, SN-α-phenethyl-N ́-triethoxysilylpropylurea, phenetyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, phenylvinyldiethoxysilane, 3-thiocyanatopropyltriethoxysilane, (tri) Decafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, N- [3- (triethoxysilyl) propyl] phthalamic acid, (3,3,3-trifluoropropyl) methyldimethoxysilane, 3, 3,3- (Trifluoropropyl) trimethoxysilane, 1-trimethoxysilyl-2- (chloromethyl) phenylethane, 2- (trimethoxysilyl) ethylphenylsulfonyl azide, β-trimethoxysilylethyl-2-pyridine , Trimethoxysilylpropyl Diethylenetriamine, N-[(3-Trimethoxysilyl) propyl] Examples thereof include ethylenediamine triacetate sodium salt, N- (3-trimethoxysilylpropyl) pyrrole, vinylmethyldiethoxysilane, vinyltris-t-butoxysilane and the like. However, the compound of the above general formula used in the present invention is not limited to the above specific examples.

【0024】

One of the compounds represented by the above general formula may be used, but any two or more kinds may be mixed and used. Further, in order to improve the film forming property, a hydrolyzate of the compound represented by the above general formula may be used. Hydrolysis of the above compounds is carried out by adding and mixing pure water, or by adding an acid such as hydrochloric acid, nitric acid, sulfuric acid, acetic acid, oxalic acid, citric acid, or tartaric acid as a catalyst, or acidic water, or ammonia, sodium hydroxide, or water. Basic water to which a base such as potassium oxide, monoethanolamine, diethanolamine, or triethanolamine is added as a catalyst may be added and stirred. The degree of progress of hydrolysis can be adjusted by controlling the amount of water added, but in general, the amount of water added should be equal to or more than the hydrolyzable group of the above compound to be hydrolyzed. Is desirable. Further, when hydrolyzing the above compound, it is also possible to add a solvent such as alcohols for the purpose of homogenizing the reaction system of hydrolysis.

【0025】

The blending ratio of the composite titanium oxide particles and the compound represented by the general formula or a hydrolyzate thereof is generally preferably 1/50 to 10/1 in terms of solid content ratio. If the ratio is 1/50, the refractive index of the cured film may not be sufficiently high, and if it exceeds 10/1, cracks may occur between the coating film and the substrate, or transparency may decrease, which is not preferable. .. The coating composition of the present invention has fine particles made of metal oxides such as aluminum, antimonide, zirconium, tin, tungsten, and silicon in order to match the refractive index with the optical component used as the substrate and further improve the scratch resistance. A state-inorganic substance may be added. Further, various surfactants can be added for the purpose of improving the wettability at the time of coating and improving the smoothness of the cured film. Further, an ultraviolet absorber, an antioxidant and the like can be blended to the extent that the physical properties of the coating film are not affected.

【0026】

The coating composition may be applied onto a base material, which is an optical material, by a dipping method, a spin coating method, a spray spraying method, or the like and cured. It is preferable to apply by the dipping method or the spin method from the viewpoint of surface accuracy and the like. Before applying the coating composition to the underlying optics, the surface of the optics is chemically treated with an acid, alkali or various organic solvents; physical treatment with plasma or UV light; cleaning treatment with various detergents; or various By subjecting to the primer treatment using a resin, the adhesion between the base material and the cured film can be improved. The coating composition may be cured by heat treatment, for example, hot air drying or activation energy ray irradiation. It is preferably cured in hot air of 70 ° C to 200 ° C, and particularly preferably cured at 90 ° C to 150 ° C. Far infrared rays or the like can be used as the active energy ray, and damage due to heat can be suppressed to a low level.

【0027】

In curing the coating film by heating, various curing catalysts may be added to the coating composition in order to shorten the heating time or cure at a low temperature. Examples of the curing catalyst include amine agents such as allylamine and ethylamine, and various acids and bases containing Lewis acid and Lewis base, such as organic carboxylic acid, chromium acid, hypochlorous acid, boric acid, bromic acid and selenic acid. , Metal salts such as thiosulfate, orthosilicic acid, thiosian acid, nitrite, aluminic acid, carbonic acid, perchloric acid, alkoxides such as aluminum, zirconium, titanium, and complex compounds thereof.

【0028】

According to the present invention, there is provided an optical component having a coating film formed by applying and curing the above coating composition. The optical member as the base material is not particularly limited as long as it does not impair transparency, and is, for example, a methyl methacrylate homopolymer, a copolymer containing methyl methacrylate and one or more other monomers as monomer components, and diethylene glycol bisallyl. Carbonate-only copolymer, copolymer containing diethylene glycol bisallyl carbonate and one or more other monomers as monomer components, transparent synthetic resin such as polycarbonate, polystyrene, polyvinyl chloride, polyethylene terephthalate, polyurethane, inorganic glass, etc. Can be used. Examples of the optical component include a spectacle lens, a camera lens, an optical filter attached to a display of a word processor, a window glass of an automobile, and the like.

【0029】

Further, an antireflection film may be further formed on the surface layer of the coating film by a vacuum vapor deposition method, a sputtering method, an ion plating method or the like. Examples of the multilayer antireflection film provided for such a purpose include an antireflection film in which low refractive index layers and high refractive index layers are alternately laminated. As the high refractive index layer, a titanium oxide film, an aluminum oxide film, a tantalum oxide film, a zirconium oxide film or the like can be used, but from the viewpoint of transparency, durability and the like, a metal oxide containing tantalum, zirconium and yttrium. It is particularly preferable to use the mixed vapor deposition film of. Examples of the low refractive index layer include a magnesium fluoride film and the like, but silicon dioxide (SiO) in particular from the viewpoint of scratch resistance, heat resistance and the like.₂) It is particularly preferable to use a film.

【0030】

Zirconium oxide (ZrO) is used as a mixed vapor deposition film of metal oxides containing tantalum, zirconium and yttrium.₂) Powder, tantalum oxide (Ta₂O₅) It is preferable that the powder is mixed and pelletized by pressure pressing or sintering, and then vapor-deposited by an electron beam heating method. The mixing ratio (molar ratio) of each powder is ZrO.₂ Ta against 1.0₂O₅0.8 ~ 1.8, Y₂O₃ It is preferably 0.05 to 0.3. 1 mol of ZrO₂Against Ta₂O₅If is less than 0.8 mol or more than 1.8 mol, absorption may easily occur in the obtained mixed-film deposition film, and Y₂O₃If is less than 0.15 mol, absorption may easily occur in the similarly obtained mixed-film deposition film, and Y₂O₃If it exceeds 0.3 mol, the vapor deposition rate becomes high, absorption is likely to occur in the obtained mixed vapor deposition film, and the vapor deposition raw material is likely to be scattered, which may be difficult to control, which is not preferable. The mixed metal vapor deposition film thus obtained is Ta₂O₅Like ZrO₂It is chemically extremely stable compared to ZrO₂It has transparency comparable to. Further, the refractive index shows a high value of 2.05, for example, which is effective from the viewpoint of film design.

【0031】

The film configuration of the above-mentioned multi-layer antireflection film is generally a two-layer film of λ / 2-λ / 4, λ / 4-λ / 4-λ / 4 or λ / 4-λ / 2-λ / 4. A three-layer film is preferable, but a multi-layer film having four or more layers may be used from the viewpoint of reflection characteristics. In the case of a three-layer film, the λ / 4 film of the first layer counting from the substrate side is the above-mentioned mixed film and SiO.₂A three-layer symmetric equivalent membrane using a membrane or a two-layer composite equivalent membrane can be used. Further, the optical component of the present invention may be subjected to antistatic treatment, dimming treatment and the like, if necessary. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

【0032】

[Example]

Example 1 Titanium isopropoxide 2.24 g (8.0 x 10)^-3Mole) and 0.04 g of hydroxypropyl cellulose (150 cp) were dissolved in 300 ml of absolute ethanol and 0.57 ml (3.2 x 10) at room temperature with stirring with a magnetic stirrer.^-2A mixture of (mo) distilled water and 100 ml of absolute ethanol was added dropwise to hydrolyze titanium isopropoxide to give a slightly turbid, almost transparent titanium oxide sol. The particle size was observed using a scanning electron microscope, and it was confirmed that the particle size of titanium oxide was 60 nm. 2 × 10 in the obtained sol^-4After molar amounts of zinc chloride were added to dissolve and thoroughly mixed, 1.8 ml of a pH 10 aqueous sodium hydroxide solution was added to precipitate zinc oxide on the surface of the titanium oxide particles. From the same particle size observation as above, it was confirmed that the particle size of the zinc oxide-coated titanium oxide was 80 nm. The above sol containing the composite titanium oxide particles was concentrated to a solid content concentration of 8% by weight by a rotary evaporator to obtain a white translucent sol.

【0033】

A film-forming agent solution was prepared by diluting 1.96 g of 3-glycidoxypropyltrimethoxysilane with 8 ml of ethanol, adding 0.45 ml of a pH 4 hydrochloric acid aqueous solution, and sufficiently hydrolyzing at room temperature. The above sol and the film-forming agent solution were sufficiently mixed to obtain a coating composition. No sedimentation was observed in this coating composition, and there was almost no change with time even after being allowed to stand for 1 month, and the coating composition was excellent in stability. The above coating composition was applied to the surface of the base material, polymethylmethacrylate, by a spin coating method at 2000 rpm, and then cured at 120 ° C. for 30 minutes to manufacture an optical component. The index of refraction of the coating film by ellipsometer (wavelength 633 nm) was 1.55. There was no change in the visible light spectrum even after irradiation with a xenon lamp for 200 hours, and the coating film had excellent light resistance.

【0034】

Example 2 A white translucent sol having a solid content concentration of 8% by weight was obtained by the same method as in Example 1. 0.98 g of 3-glycidoxypropyltrimethoxysilane was diluted with 4 ml of ethanol, 0.22 ml of a hydrochloric acid aqueous solution having a pH of 4 was added, and the mixture was sufficiently hydrolyzed at room temperature to prepare a film-forming agent solution. The above sol and the film-forming agent solution were sufficiently mixed to obtain a coating composition. No sedimentation was observed in this coating composition, and there was almost no change with time even after standing for 1 month, and the coating composition was excellent in stability. Using polymethylmethacrylate as a base material and the above coating composition, an optical component was produced in the same manner as in Example 1. The index of refraction of the coating film by ellipsometer (wavelength 633 nm) was 1.57. There was no change in the visible light spectrum even after irradiation with a xenon lamp for 200 hours, and the coating film had excellent light resistance.

【0035】

Example 3 In the same manner as in Example 1, a white translucent sol having a solid content concentration of 0.8% by weight was obtained. A film-forming agent solution was prepared by diluting 1.96 g of 3-glycidoxypropyltrimethoxysilane with 8 ml of ethanol, adding 0.45 ml of a pH 4 hydrochloric acid aqueous solution, and sufficiently hydrolyzing at room temperature. The above sol and the film-forming agent solution were sufficiently mixed to obtain a coating composition. No sedimentation was observed in this coating composition, and there was almost no change with time even after standing for 1 month, and the coating composition was excellent in stability. Using polymethylmethacrylate as a base material and the above coating composition, an optical component was produced in the same manner as in Example 1. The index of refraction of the coating film by ellipsometer (wavelength 633 nm) was 1.53. There was no change in the visible light spectrum even after irradiation with a xenon lamp for 200 hours, and the coating film had excellent light resistance.

【0036】

Example 4 Titanium isopropoxide 4.48 g (1.6 x 10)^-2Mole) and 0.08 g of hydroxypropyl cellulose (150 cp) were dissolved in 300 ml of absolute ethanol and 1.14 ml (6.4 x 10) with stirring at room temperature with a magnetic stirrer.^-2A mixture of (molar) distilled water and 100 ml of absolute ethanol was added dropwise to hydrolyze titanium isopropoxide. 4x10 in this sol^-4After molar amounts of zinc chloride were added to dissolve and thoroughly mixed, 3.6 ml of a pH 10 aqueous sodium hydroxide solution was added to precipitate zinc oxide on the surface of titanium oxide particles. The obtained sol was concentrated to a solid content concentration of 16% by weight by a rotary evaporator to obtain a white translucent sol.

【0037】

A film-forming agent solution was prepared by diluting 0.98 g of 3-glycidoxypropyltrimethoxysilane with 4 ml of ethanol, adding 0.22 ml of an aqueous hydrochloric acid solution having a pH of 4, and sufficiently hydrolyzing at room temperature. The above sol and the film-forming agent solution were sufficiently mixed to obtain a coating composition. No sedimentation was observed in this coating composition, and there was almost no change with time even after standing for 1 month, and the coating composition was excellent in stability. Using polymethylmethacrylate as a base material and the above coating composition, an optical component was produced in the same manner as in Example 1. The index of refraction of the coating film by ellipsometer (wavelength 633 nm) was 1.61. There was no change in the visible light spectrum even after irradiation with a xenon lamp for 200 hours, and the coating film had excellent light resistance.

【0038】

Comparative example 1 Titanium isopropoxide 2.24 g (8.0 x 10)^-3Mole) and 0.04 g of hydroxypropyl cellulose (150 cp) were dissolved in 300 ml of absolute ethanol and 0.57 ml (3.2 x 10) with stirring at room temperature with a magnetic stirrer.^-2A mixture of (mol) distilled water and 100 ml of absolute ethanol was added dropwise to hydrolyze titanium isopropoxide to obtain a slightly turbid, almost transparent titanium oxide sol. The particle size of titanium oxide was found to be 60 nm by observing the particle size with a scanning electron microscope. The sol was concentrated to a solid content concentration of 4% by weight by a rotary evaporator to obtain a white translucent sol.

【0039】

1.96 g of 3-glycidoxypropyltrimethoxysilane was diluted with 8 ml of ethanol, 0.45 ml of an aqueous hydrochloric acid solution having a pH of 4 was added, and the mixture was sufficiently hydrolyzed at room temperature to prepare a film-forming agent solution. The above sol and the film-forming agent solution were sufficiently mixed to obtain a coating composition. The above coating composition was spin-coated on the surface of the base material, polymethylmethacrylate, at 2000 rpm, and then cured at 120 ° C. for 30 minutes to manufacture optical components. After 200 hours of irradiation with a xenon lamp, whitening of the film was observed.

【0040】

Comparative example 2 Titanium isopropoxide 2.24 g (8.0 x 10)^-3Mole) and 0.04 g of hydroxypropyl cellulose (150 cp) were dissolved in 300 ml of absolute ethanol and 0.57 ml (3.2 x 10) with stirring at room temperature with a magnetic stirrer.^-2A mixture of (molar) distilled water and 100 ml of absolute ethanol was added dropwise to hydrolyze titanium isopropoxide to give a slightly turbid, almost transparent titanium oxide sol. 2x10 in this sol^-4A molar amount of zinc chloride was added to dissolve and mix. This sol was concentrated to a solid content concentration of 4% by weight by a rotary evaporator to obtain a white translucent sol.

【0041】

1.96 g of 3-glycidoxypropyltrimethoxysilane was diluted with 8 ml of ethanol, 0.45 ml of an aqueous hydrochloric acid solution having a pH of 4 was added, and the mixture was sufficiently hydrolyzed at room temperature to prepare a film-forming agent solution. The above sol and the film-forming agent solution were sufficiently mixed to obtain a coating composition. The surface of the base material, polymethylmethacrylate, was spin-coated at 2000 rpm, but huge crystals of zinc chloride were precipitated, resulting in a film with low transparency.

【0042】

Comparative example 3 1.96 g of 3-glycidoxypropyltrimethoxysilane was diluted with 8 ml of ethanol, 0.45 ml of an aqueous hydrochloric acid solution having a pH of 4 was added, and the mixture was sufficiently hydrolyzed at room temperature to prepare a film-forming agent solution. Next, in this film-forming agent solution, 10 ml of a methanol dispersion of titanium oxide fine particles coated with cerium oxide fine particles (described in JP-A-4-110918; cerium oxide / titanium oxide = 1: 1, solid content). (Concentration 10%) was added and mixed well to obtain a coating composition. The above coating composition was spin-coated on the surface of the base material, polymethylmethacrylate, at 2000 rpm, and then cured at 120 ° C. for 30 minutes to manufacture optical components. The coating film of this optical component was not yellowish. After 200 hours of irradiation with a xenon lamp, the film was colored light dark green.

【0043】

[Effect of the invention]

Since the composite titanium oxide particles of the present invention are coated with zinc oxide having sufficient absorption characteristics near the absorption edge wavelength of titanium oxide, the photocatalytic property of titanium oxide is sufficiently suppressed and the light resistance is excellent. Koti give the packaging film. Further, since zinc oxide can suppress the photocatalyst of titanium oxide with a very small amount of coating, the ratio of titanium oxide in the composite titanium oxide particles can be increased, and the high refractive index of titanium oxide is not impaired. Moreover, zinc oxide is colorless in the visible range and can be blended in a large amount in the coating composition to form a colorless and transparent high-refractive index coating film. Further, the optical component of the present invention is useful because it has a colorless high-refractive index coating film in the visible region.