JPH11255515A - Antifog material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antifog material without requiring a treatment at a high temperature, having transparency, releasability and weather resistance, same as or more than these of the conventional one, and further having a nearly same surface hardness comparable to that of a coating membrane obtained by a firing method, a decreased reflection index regulated by decreasing the difference of refractive indexes of the antifog material and a substrate, and persistent antifog activities. SOLUTION: This antifog material comprises (1) titanium oxide and a metal oxide having a refractive index different from the titanium oxide, or an oxide containing titanium and a metal, (2) noble metal particles and (3) a transition metal. The method for producing the antifog material comprises adding a fluorine scavenger to an aqueous solution containing at least a fluoro complex titanium compound, a fluoro complex metal compound, noble metal colloid particles or a noble metal compound, and a transition metal compound to provide a precipitate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a titanium oxide-based antifogging material, a coating film made of the antifogging material, and a base material such as a spectacle lens having the coating film. The antifogging material of the present invention is an antifogging material having an excellent antifogging effect and low surface reflectance. Further, the present invention relates to a method for producing the above antifogging material.

[0002]

2. Description of the Related Art Titanium oxide is known to have a photocatalytic function, and by forming a titanium oxide layer on the surface,
Since it can impart antibacterial properties, antifouling properties, antifogging properties, and the like, applications in a wide range of fields are being promoted. However, titanium oxide has a high refractive index of 2.60, and when provided on a low refractive index substrate such as glass, the titanium oxide layer becomes a reflective layer,
It will have a high reflectivity. As a result, for example, when coating on spectacle lenses, or limited field of view,
There is a problem that the appearance may be impaired.

Therefore, in order to eliminate the high reflectance of the titanium oxide coating layer, a substance having a low refractive index such as silica is mixed. As such a thin film, for example,
A mixture composed of a mixture of a silicon precursor, an amorphous silica precursor, and photocatalyst particles (specifically, a mixture of silica sol, trimethoxymethylsilane, and titania sol) is applied to a substrate and fired at 150 ° C. at a low temperature. There is a titanium oxide-silica mixed thin film formed by doing this. In this method, a film formed on a substrate by a sol-gel method is cooled at a low temperature (10
It is characterized in that a film can be formed by firing at 0 to 150 ° C.). (JP-A-9-59041).

[0004]

However, when silica is mixed with titanium oxide, the photocatalytic function of titanium oxide is diluted, and the photocatalytic function is reduced.
Furthermore, the above method requires firing at 100 to 150 [deg.] C., albeit at a low temperature, and has a problem that it cannot be provided on a substrate made of plastic or the like having low heat resistance. For example, when imparting anti-fog properties to mirrors and spectacle lenses, it is desirable that a film can be formed on a material having low heat resistance, such as plastic, and that the anti-fog function is high and durable.

Accordingly, an object of the present invention is to provide a film which does not require treatment at a high temperature, has the same or higher transparency, peelability, and weather resistance as a conventional product, and is obtained by a firing method. Another object of the present invention is to provide an anti-fogging material having a surface hardness of the same level as that of the above, reducing the difference in refractive index from the base material, reducing the reflectance, and having a long-lasting anti-fogging effect. It is a further object of the present invention to provide a substrate having the above-mentioned anti-fogging material as a coating film and a method for producing the above-mentioned anti-fogging material which does not require treatment at a high temperature.

[0006]

The present invention for attaining the above object comprises (1) titanium oxide and a metal oxide having a different refractive index from titanium oxide or an oxide containing titanium and a metal (provided that the metal The metal oxide has a refractive index different from that of titanium oxide), (2) noble metal particles, and (3) a transition metal. Furthermore, the present invention relates to a coating film made of the above antifogging material. Also,
The present invention relates to a substrate provided with the above coating film on the surface. This base material can be made of, for example, plastic, and the coating film can be formed on a base layer formed on plastic. The substrate is
For example, it can be a spectacle lens. Further, the present invention includes at least a fluoro complex titanium compound, a fluoro complex metal compound (a metal oxide derived from this compound has a different refractive index from titanium oxide), a noble metal colloid particle or a noble metal compound, and a transition metal compound. The present invention relates to a method for producing an antifogging material of the present invention, which method includes adding a fluorine scavenger to an aqueous solution to form a precipitate.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The antifogging material of the present invention comprises (1) titanium oxide and a metal oxide having a different refractive index from titanium oxide;
Or an oxide containing titanium and a metal (however, the metal oxide of the metal has a different refractive index from titanium oxide), (2) noble metal particles (however, the noble metal particles contain the titanium oxide or titanium and a metal) (In contact with the oxide), and (3) a transition metal (provided that the transition metal is doped in the titanium oxide or the oxide containing titanium and the metal).

The "metal oxide having a different refractive index from titanium oxide" includes, for example, silicon oxide, zirconium oxide, yttrium oxide, aluminum oxide and the like. Examples of the metal constituting the “oxide containing titanium and metal” include metals included in the metal oxides exemplified as the metal oxide having a different refractive index from the above titanium oxide. Specific examples of the “oxide containing titanium and metal” include a Ti—Si oxide, a Ti—Zr oxide, a Ti—Y oxide, and a Ti—Al oxide.

For example, silicon oxide has a refractive index of 1.48.
Which is significantly lower than the refractive index of titanium oxide, 2.60,
By mixing silicon oxide, the refractive index of the anti-fogging material can be reduced, and can be close to the refractive index (1.4 to 1.7) of glass or plastic which is the base material of the spectacle lens. The composition ratio of titanium oxide and a metal oxide having a different refractive index from titanium oxide is appropriately determined in consideration of the refractive index and the photocatalytic activity required for the antifogging material or the coating film made of the antifogging material. . However, the content of the metal oxide having a refractive index different from that of titanium oxide in the antifogging material is such that when the antifogging material is a coating film, the refractive index difference between the coating film and the base material is 1 or less. , Preferably 0.5 or less, more preferably 0.1 or less, from the viewpoint of reducing the reflectance.

Further, the antifogging material of the present invention contains noble metal particles. The noble metal particles are contained in contact with the titanium oxide or “oxide containing titanium and metal”. By supporting a noble metal on titanium oxide or "oxide containing titanium and metal", the photocatalytic performance of "oxide containing titanium titanium oxide and metal" can be improved. As the noble metal, for example, Ag, Cu, Au, P
t, Pd, Rh, Ir and the like can be mentioned. However,
These are not limiting. The content and particle size of the noble metal particles can be appropriately determined in consideration of the photocatalytic activity required for the antifogging material.

The antifogging material of the present invention further contains a transition metal, and the transition metal is doped in the titanium oxide or the “oxide containing titanium and metal”. By doping the titanium oxide or the “oxide containing titanium and metal” with a transition metal ion, the durability of the photocatalytic activity of the titanium oxide or the “oxide containing titanium and metal” can be improved. As the transition metal ion, for example,
Nd, V, Cr, Mn, Fe, Co, Ni, Cu, Sc
And the like. However, it is limited to these. The doping amount of the transition metal ion can be appropriately determined in consideration of the type of the transition metal ion and the photocatalytic activity required for the titanium oxide-based coating film.

The antifogging material of the present invention can be obtained by adding a fluorine scavenger to an aqueous solution containing, for example, a fluoro complex titanium compound, a fluoro complex metal compound, a metal colloid particle or a noble metal compound, and a transition metal compound to form a precipitate. It can be formed by generating. When the antifogging material is formed as a coating film on a base material such as a spectacle lens, it can be prepared by immersing the base material such as a spectacle lens in the above solution (treatment liquid).

In the above production method, an aqueous solution containing a fluoro complex titanium compound and a fluoro complex metal compound is prepared. The aqueous solution containing the fluoro complex titanium compound can be prepared by dissolving titanium oxide in hydrofluoric acid. Alternatively, a titanium hydroxide or oxyhydroxide is dissolved in an aqueous solution of an alkali metal hydrogen difluoride such as ammonium hydrogen difluoride or sodium hydrogen difluoride to synthesize a fluoro complex titanium compound. Can also. Similarly, the aqueous solution containing a fluoro complex metal compound, for example, when the fluoro complex metal compound is an aqueous solution containing a fluoro complex silicon compound,
It can be prepared by dissolving silica in hydrofluoric acid. Alternatively, dissolving a hydroxide or oxyhydroxide of silica in an aqueous solution of an alkali metal hydrogen difluoride such as ammonium hydrogen difluoride or sodium hydrogen difluoride to synthesize a fluoro complex silicon compound Can also. The aqueous solution containing the fluoro complex titanium compound and the fluoro complex metal compound can be prepared by mixing these solutions.

The concentration of the fluoro complex titanium compound and the fluoro complex metal compound in the aqueous solution can be appropriately selected in consideration of the ratio of the oxide in the formed film.
It is appropriate to prepare and use an aqueous solution having a metal amount of usually 10 ^-9 to 10 mol / L, preferably 10 ^-6 to 10 ^-1 mol / L. Here, the aqueous solution may be an aqueous solution containing excess hydrogen fluoride used for synthesizing the complex compound.

[0015] The aqueous solution containing the fluoro complex titanium compound and the fluoro complex metal compound may contain metal oxide particles such as titanium oxide particles and silica particles as seed crystals. The seed crystal is fine in the range of 0.001 to 10 μm, preferably about 0.001 to 1 μm, and the amount of the seed crystal is appropriately determined in consideration of the amount of a metal oxide such as titanium oxide or silica to be precipitated. Can decide. In the method of the present invention, a metal oxide such as titanium oxide and silica can be obtained as a stable phase by using a seed crystal of metal oxide particles such as titanium oxide particles and / or silica particles as the seed crystal. Further, the precipitation rate can be controlled by selecting the particle diameter and the amount of the seed crystal. If necessary, seed crystals can be replenished during the precipitation.

Further, the aqueous solution containing the above-mentioned fluoro complex titanium compound and fluoro complex metal compound contains noble metal colloid particles and / or noble metal compound as a noble metal particle source. Examples of the noble metal colloid particles include Ag, Cu, Au, Pt, Pd, Rh, and Ir. The particle size of the colloidal particles and the amount of the colloidal particles added to the aqueous solution can be appropriately changed depending on the intended coating film. However, in consideration of the dispersibility of the colloid particles in the aqueous solution and the state of existence in the composite membrane, the particle diameter can be, for example, in the range of 10 ^{−3 to 1} μm. Also,
The amount of the colloidal particles added to the aqueous solution is, for example, 10 ⁻² per liter of the treatment liquid in consideration of the concentration of the fine particles in the film.
It can be mentioned in the range of ~10 ² g. Also, like the seed crystal, colloidal particles can be added and supplemented during the reaction.

Examples of the metal ions contained in the noble metal compound include, for example, Ag, Cu, Au, Pt, Pd,
Rh, Ir and the like can be mentioned. Compounds containing these ions include, for example, AgF.xH ₂ O, A
_{gNO 3, Rh (NO 3)} 3 · 2H 2 O, Cu (NO 3) 2 · 3
_{H 2 O, CuF 2 · 2H} 2 O, CuCl 2 · 2H 2 O, Pt
_{Cl 4 · 5H 2 O, Cu} (NO 3) 2 · 3H 2 O, CuSO 4
・ 5H ₂ O, CuSO ₄ , CuCl ₂・ 2H ₂ O, CuF ₂
· 2H ₂ O, can be cited CuCl or the like. The concentration of the noble metal compound is, for example, 10 ⁻⁴ to 1 −1 per 1 liter of the treatment liquid in consideration of the solubility and the doping amount to titanium oxide.
It can be in the range of 0 mol. Further, the noble metal compound can be replenished during the reaction.

The aqueous solution further contains a transition metal compound to be doped. Examples of the transition metal ion include Nd, V, Cr, Mn, Fe, Co, Ni, Cu,
Sc and the like can be mentioned. Examples of the transition metal compound include Cr (NO ₃ ) ₃ .xH ₂ O and VOSiO _4.
2H ₂ O, VOCl ₃ , Cr ₂ (SO ₄ ) ₃ .18H ₂ O,
CrCl ₃ .xH ₂ O, MnCl ₂ .4H ₂ O, MnC
l ₂ , Mn (NO ₃ ) ₂ .6H ₂ O, MnSO ₄ .6H ₂ O,
MnF ₂ , MnF ₃ .3H ₂ O, FeCl ₂ .4H ₂ O, F
eCl ₂ , FeCl ₃ .6H ₂ O, FeCl ₃ , Fe (NO
_{3) 2 · 9H 2 O,} FeSO 4 · 7H 2 O, FeSO 4, (N
H ₄ ) Fe (SO ₄ ) ₃ .xH ₂ O, Co (NO ₃ ) ₂ .6H _{2
O, CoSO 4 · 7H 2 O} , NiCl 2 · 6H 2 O, Ni
_{(NO 3) 2 · 6H 2} O, NiSO 4, Sc (SO 4) 3 · x
H ₂ O is exemplified.

The concentration of the transition metal compound can be, for example, in the range of 10 ^-4 to 10 mol per liter of the treatment liquid in consideration of the solubility and the doping amount to titanium oxide. Further, a transition metal compound can be replenished during the reaction.

The fluoride ion scavenger used in the present invention is capable of trapping fluorine ions from an aqueous solution containing a fluoro complex titanium compound and a fluoro complex metal compound to form the antifogging material of the present invention as a precipitate. Anything is fine. Generally, a fluoride ion scavenger includes a homogeneous system used by being dissolved in a liquid phase and a heterogeneous system which is a solid. Depending on the purpose, even if one of these two is used,
You can use them together.

The homogeneous fluoride ion scavenger reacts with hydrogen fluoride to form a stable fluoro complex titanium compound and / or fluoride, thereby equilibrating the fluorine ions to precipitate titanium oxide and silica. It is something to move. Examples thereof include boric acid such as orthoboric acid and metaboric acid, as well as aluminum chloride, sodium hydroxide, and aqueous ammonia. Such capture agents are typically
It is used in the form of an aqueous solution, but may be added in the form of a powder and dissolved in the system. Such addition of the scavenger may be performed once or several times intermittently, or may be performed continuously at a controlled feed rate, for example, at a constant rate.

As the heterogeneous fluoride ion scavenger,
Aluminum, titanium, iron, nickel, magnesium,
Examples thereof include metals such as copper and zinc, ceramics such as glass, and compounds such as silicon, calcium oxide, boron oxide, aluminum oxide, silicon dioxide, and magnesium oxide. When such solid matter is added or inserted into the solution, F near solids ^- are consumed, because its concentration decreases, and shifts the chemical equilibrium of the portion, titanium oxide and silica are deposited. When such a solid is used, depending on the method of addition or insertion and the reaction conditions, titanium oxide can be deposited on the entire surface of the substrate immersed in the aqueous solution, or the deposition can be locally performed, that is, the solid can be selected. It is also possible to limit to the vicinity where. Alternatively, by using a combination of a homogeneous and a heterogeneous fluoride ion scavenger, the thickness of the deposit thin film on the substrate surface can be partially increased. The amount of the homogeneous fluoride ion scavenger is usually from 10 ^-4 to 1,000%, preferably from 10 ^{-2 to} 5, based on the amount of fluoride ions in the solution.
It is used in the range of 00%.

When the antifogging material is formed on the substrate as a coating film, the substrate is immersed in the aqueous solution of the fluoro complex compound before, after, simultaneously with or after the addition or insertion of the fluoride scavenger. No problem. However, when using a substrate that may be affected by the system, attention must be paid to the composition of the solution, the reaction conditions, and the timing of immersion. The reaction temperature can be arbitrarily set as long as the system maintains an aqueous solution, but is preferably in the range of 10 to 80 ° C. The reaction time is also arbitrary. For example, when the target precipitate is large, the reaction time can be lengthened accordingly.

Thus, a coating film made of the anti-fogging material of the present invention can be formed on the surface of the substrate. The thus-formed antifogging material and the coating layer comprising the antifogging material of the present invention can be obtained as titanium oxide crystallized according to the conditions without a heating step such as baking. . However,
A heating step may be provided as necessary.

The coating film of the present invention comprises the above-mentioned antifogging material of the present invention. The thickness of the coating film is not particularly limited, but from the viewpoint of reducing the reflectance, for example,
It is appropriate that the thickness be 0.1 μm or less. Furthermore, the substrate of the present invention is a substrate provided with the above-mentioned coating film of the present invention on the surface. The substrate can be made of, for example, glass or plastic (organic polymer material). The plastic may be a thermoplastic resin or a thermosetting resin. Since the production method of the present invention does not require heating, there is an advantage that it can be applied to a plastic substrate having poor heat resistance. Examples of the plastic include a methyl methacrylate homopolymer, a copolymer of methyl methacrylate and one or more other monomers,
Diethylene glycol bisallyl carbonate homopolymer, copolymer of diethylene glycol bisallyl carbonate and one or more other monomers, polycarbonate,
Examples thereof include polyurethane, polythiourethane, and the like, but are not limited thereto. In the present invention, the substrate may be an eyeglass lens.

Further, the base material may have an underlayer on the surface on which the titanium oxide-based coating film is to be formed, in particular, to improve the adhesion between the plastic base material and the coating film of the present invention and to improve the adhesion of the present invention. It is preferable from the viewpoint of preventing deterioration of the plastic substrate due to the photocatalytic action of the coating film. Examples of such an underlayer include an oxide layer such as SiO ₂ , Al ₂ O ₃ , ZrO ₂ , and ITO, a fluoride layer such as CaF _2, and a metal layer such as stainless steel, copper, brass, and titanium. You may. Further, a layer obtained by laminating two or more of these layers may be used. The thickness of the underlayer can be about 0.1 to 1 μm from the viewpoint of sufficiently exhibiting the effect of the underlayer. The underlayer can be formed by a dry method such as a vacuum evaporation method or a sputtering method, or a wet method such as an aqueous solution method or a sol-gel method. The underlayer may be a single-layer film or a composite film of an oxide layer or a fluoride layer known as an antireflection film of an eyeglass lens.

[0027]

The present invention will be described in more detail with reference to the following examples. Comparative Example 1 1 mg of TiO ₂ anatase fine particles and 1 mg of SiO ₂ fine particles were
l of pure water. To this suspension, 2.8 g of ammonium hexafluorotitanate (NH ₄ ) ₂ TiF ₆ and 1.2 g of ammonium hexafluorosilicate (NH ₄ ) ₂ SiF ₆ were added and stirred to dissolve. Next, silver fluoride (AgF)
0.15 g was added and dissolved. The treatment liquid prepared as described above was transferred to a cylindrical container containing 500 ml, and immersed in a water tank maintained at 35 to 40 ° C. While maintaining the temperature of the treatment liquid at 35 to 40 ° C., 15 g of boron oxide was quickly added to the treatment liquid and stirred.
Thereafter, a plastic spectacle lens substrate having a diameter of 70 mm and a thickness of 5 mm, the surface of which was coated with a silica anti-reflection film by a vacuum evaporation method, was immersed in the treatment liquid. While keeping this state, it was left for 4 hours. After the elapse of the treatment time, the substrate was taken out of the water tank, washed lightly, and then washed with an ultrasonic cleaner. Thereafter, drying was performed at 40 ° C. to form a titanium oxide-based coating film TiO ₂ / Ag / SiO ₂ of the present invention on the substrate. The obtained substrate was irradiated with an ultraviolet lamp (black light) 10 W for 2 days. After that, it was not cloudy even if I breathed. Furthermore, the same fogging prevention effect was maintained until about 15 hours after the irradiation of the ultraviolet rays.

Example 1 1 mg of TiO ₂ anatase fine particles and 1 mg of SiO ₂ fine particles were previously prepared.
It was suspended in 400 ml of pure water. To this suspension, ammonium hexafluorotitanate (NH ₄ ) ₂ TiF ₆ 2.8 g and ammonium hexafluorosilicate (NH ₄ ) ₂ SiF ₆ 1.5 g
Was added and stirred to dissolve. Then, silver fluoride (Ag
F) 0.15 g was added and dissolved, and neodymium nitrate [Nd (NO ₃ )
₃ · xH ₂ O] were added and dissolved 0.2 g. The treatment liquid prepared as described above was transferred to a cylindrical container containing 500 ml, and immersed in a water tank maintained at 35 to 40 ° C. While maintaining the temperature of the treatment liquid at 35 to 40 ° C., 15 g of boron oxide was quickly added to the treatment liquid and stirred. Thereafter, a substrate of a plastic spectacle lens having a diameter of 70 mm and a thickness of 5 mm, the surface of which is provided with a silica antireflection film by a vacuum evaporation method, was immersed in the treatment liquid. While keeping this state, it was left for 4 hours. After the elapse of the treatment time, the substrate was taken out of the water tank, washed lightly, and then washed with an ultrasonic cleaner. Thereafter, the coating film TiO ₂ dried on the substrate at 40 ° C.
(Nd ³⁺ ) / Ag / SiO ₂ was formed. The obtained substrate was irradiated with an ultraviolet lamp (black light) 10 W for 2 days. After that, it was not cloudy even if I breathed. Furthermore, the same fogging prevention effect was maintained 36 hours after ultraviolet irradiation. The prevention effect was maintained at least twice as long as the coating film of Comparative Example 1 not doped with Nd ³⁺ . further,
After that, the fogging prevention effect was restored by irradiation with ultraviolet light for about 30 minutes.

[0029]

According to the present invention, a coating film which does not require high-temperature treatment, has the same or higher transparency, peelability, and weather resistance as a conventional product, and is obtained by a firing method It has the same surface hardness as that of titanium oxide, and has a lower refractive index than titanium oxide that retains the excellent photocatalytic function of titanium oxide,
It is possible to provide an antifogging material having an excellent antifogging effect, and it is also possible to provide a spectacle lens or the like having a coating film made of the antifogging material.

Claims (7)

[Claims] (1) titanium oxide and a metal oxide having a different refractive index from titanium oxide or an oxide containing titanium and a metal (the metal oxide of the metal has a different refractive index from titanium oxide); An antifogging material comprising (2) a noble metal particle and (3) a transition metal. 2. A coating film comprising the anti-fogging material according to claim 1. 3. A substrate provided with the coating film according to claim 2 on a surface. 4. The substrate according to claim 3, wherein the substrate is made of a plastic. 5. The substrate according to claim 4, wherein a coating film is formed on a base layer formed on the plastic. 6. The substrate according to claim 3, wherein the substrate is an eyeglass lens. 7. At least a fluoro complex titanium compound, a fluoro complex metal compound (a metal oxide derived from this compound has a different refractive index from titanium oxide), a noble metal colloid particle or a noble metal compound, and a transition metal compound. The method for producing an antifogging material according to claim 1, comprising adding a fluorine scavenger to the aqueous solution to generate a precipitate.