JP2001145974A - Anti-fogging seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anti-fogging seal for preventing the deterioration of a resin sheet caused by the oxidation and reduction reaction of photocatalyst particles. SOLUTION: A hydrophilic surface layer 5 containing photocatalyst particles is formed on the surface of a resin sheet 1 and an adhesive layer 2 is provided on the rear surface of the resin sheet 1 and a protective layer 6 preventing the deterioration of the resin sheet caused by the oxidation and reduction reaction of photocatalyst particles is provided between a base sheet 4 and the surface layer 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifogging seal which is applied to a surface of a mirror, a window glass, goggles or the like to impart an antifogging effect to the surface of these members.

[0002]

2. Description of the Related Art In an environment of high humidity, moisture in the air adheres as water droplets to the surface of a mirror or a window glass, causing fogging. Conventional means for removing such fogging is to remove water adhering to the surface by increasing the surface temperature of the mirror or window glass by means of a heater or the like and reducing the relative humidity near the surface of the mirror or window glass. It was made.

It is also conceivable that the surface of the mirror or window glass is made hydrophilic to reduce the contact angle with water, and that the moisture adhering to the surface is formed into a very thin water film to provide an antifogging effect.

Although it is not intended to exhibit an anti-fogging effect, an adhesive layer and a release layer are provided on the back side of an oxide semiconductor (photocatalyst) particle layer such as titanium oxide, and the release layer is peeled off. Japanese Patent Application Laid-Open No. 8-1010 discloses a prior art in which an oxide semiconductor particle layer is adhered to a desired location and sterilization and deodorization are performed by an oxidation-reduction action of the oxide semiconductor.

[0005]

In order to increase the surface temperature of a mirror or a window glass, equipment such as a built-in heater or high-temperature wind from the heater is blown onto the surface of the mirror or the window glass, which requires a large-scale facility and cost. It is difficult to apply to existing ones.

As a means for making the mirror or window glass surface hydrophilic, it is conceivable to apply a hydrophilic paint such as an acrylic resin, an acrylic silicone resin or an aqueous silicone. However, the contact angle of these hydrophilic paints with water is at most 50-70 °, which is insufficient to convert the moisture adhering to the surface into an extremely thin water film. It will be lost over time.

The present inventors have found that photocatalytic particles such as titanium oxide have a function of hydrolyzing (super-hydrophilizing) the surface of an article in addition to a function of decomposing dirt and malodorous components by a redox reaction. Independently learned.

The action of decomposing substances by the photocatalyst particles is based on an oxidation-reduction reaction. When the photocatalyst particles are irradiated with ultraviolet light or the like, electron-hole pairs are generated by photoexcitation. Superoxide ions (O ²⁻ ) are generated, and holes oxidize surface hydroxyl groups to generate hydroxyl radicals (.OH), and these highly reactive active species (O ²⁻ and .OH) are generated. It decomposes substances attached to the surface by a redox reaction.

On the other hand, the hydrophilizing action of the photocatalyst particles newly discovered by the present inventors has not been completely elucidated on the theoretical basis, but the hydroxyl group (O 2) is formed by the photocatalytic effect.
H ^-) chemically adsorbed onto the surface of the photocatalyst particles, or a hydroxyl group (OH ^-) is replaced with an organic group, further the hydroxyl (OH ^-)
It is believed that the water molecules in the air are physically adsorbed on the surface, and that the surface water is increased by increasing the amount of physically adsorbed water, thereby realizing a superhydrophilic surface.

As a specific example, a case where the surface layer is made of a silicone resin having a Si—O bond will be described. As shown in FIG.
Since the alkyl group (R) is bonded to the atom, the surface layer shows hydrophobicity. However, when light having an energy higher than the band gap energy of the photocatalyst particles is irradiated, first, as shown in FIG. alkyl group (R) by the photocatalytic effects hydroxyl - is substituted (chemisorption), further the hydroxyl ^(OH) - exhibit hydrophilic water molecules in the air are physically adsorbed ^(OH).

Further, titanium oxide (Ti) is used as photocatalyst particles.
O ₂ ) will be described. The state shown in FIG. 2A before the light irradiation is changed to the state shown in FIG. 2A when the light is irradiated, as shown in FIG. 2B. hydroxyl group constituting the (OH ^-) is a Ti atom, a hydrogen atom (H ⁺⁾ is chemically adsorbed to the oxygen atom (O), further the hydroxyl - water molecules and in the air a hydrogen atom (H ^{+) (OH)} Exerts hydrophilicity by physical adsorption.

In the above description, it is clear that the decomposing action and the hydrophilizing action of the substance are completely different. However, in a specific example, even in the case of TiO ₂ , the anatase type TiO ₂ can be oxidized and reduced. However, rutile type TiO ₂ hardly exhibits a substance decomposing action based on a redox reaction. Also, among the photocatalysts, tin oxide does not show a decomposition effect of a substance based on a redox reaction. In these photocatalyst particles, the energy level of the conduction band is not sufficiently high, so that the reduction reaction does not proceed. As a result, the electrons excited by the photoexcitation in the conduction band become excessive, and the electron-hole pairs generated by the photoexcitation are oxidized and reduced. It is believed that they recombine without participating in the reaction. However, both rutile TiO ₂ and tin oxide exhibit a hydrophilizing action. Further, the photocatalytic layer needs to have a thickness of at least 100 nm or more in order to exhibit the decomposing action of the substance.
Above is possible. From these facts, it can be said that the decomposition action of the substance by the photocatalyst and the hydrophilization action are completely different.

Although the seal disclosed in Japanese Patent Application Laid-Open No. H8-1010 does not mention the hydrophilizing action in the specification, it forms a layer of photocatalyst particles such as titanium oxide, and thus has a hydrophilic action. Should demonstrate. However, the technique described in Japanese Patent Application Laid-Open No. H8-1010 utilizes an oxidation-reduction reaction of photocatalyst particles,
For example, in order to easily form a sheet, or to easily adhere to a mirror or glass, to mix the photocatalyst particles in the transparent resin sheet, or when the photocatalyst particles are laminated on the transparent resin sheet, the transparent resin sheet Corrosion / deterioration occurs due to redox reaction of photocatalytic particles.

[0014]

Means for Solving the Problems The present inventors have found that photocatalytic particles such as titanium oxide have a function of decomposing dirt and the like by an oxidation-reduction reaction and a function of making the surface of an article hydrophilic (super-hydrophilic). The present invention has been made based on the fact that the present invention has a unique idea.

[0015]

The anti-fog seal according to the present invention has a hydrophilic surface layer containing photocatalyst particles formed on the front side of the resin sheet, an adhesive layer provided on the back side, and a resin sheet and the surface layer. A protective layer for preventing deterioration of the resin sheet due to the oxidation-reduction reaction of the photocatalyst particles was provided therebetween.

Further, another anti-fog seal according to the present invention is provided with an adhesive layer on the back side of a resin sheet, and contains photocatalyst particles in the resin sheet. A protective film for preventing deterioration of the surrounding resin due to the reaction was formed. In addition, if the protective film on the surface of the photocatalyst particles exposed to the outside air is removed by etching or the like, the hydrophilicity is further improved.

The adhesive layer need not be provided on the entire back surface of the resin sheet, but may be provided only on a part of the resin sheet, or a colored layer may be provided between any of the layers.

The following are examples of the resin constituting the resin sheet. Methyltrichlorosilane, methyltribromosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane,
Methyltri-t-butoxysilane, ethyltrichlorosilane, ethyltribromosilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, ethyltri-t-butoxysilane, n-propyltrichlorosilane, n-propyltribromosilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltriisopropoxysilane, n-propyltri-t-butoxysilane, n-hexyltrichlorosilane, n-hexyltribromosilane, n-hexyltrimethoxysilane N-hexyltriethoxysilane, n-hexyltriisopropoxysilane, n-hexyltri-t-butoxysilane, n-decyltrichlorosilane, n-decyltribromosilane, n
-Decyltrimethoxysilane, n-decyltriethoxysilane, n-decyltriisopropoxysilane, n-decyltri-t-butoxysilane, n-octadecyltrichlorosilane, n-octadecyltribromosilane, n-
Octadecyltrimethoxysilane, n-octadecyltriethoxysilane, n-octadecyltriisopropoxysilane, n-octadecyltri-t-butoxysilane,
Phenyltrichlorosilane, phenyltribromosilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriisopropoxysilane, phenyltri-t-butoxysilane, tetrachlorosilane, tetrabromosilane, tetramethoxysilane, tetraethoxysilane, tetraisosilane Propoxysilane, tetrabutoxysilane, dimethoxydiethoxysilane, dimethyldichlorosilane, dimethyldibromosilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldichlorosilane, diphenyldibromosilane, diphenyldimethoxysilane, diphenyldiethoxysilane, Phenylmethyldichlorosilane, phenylmethyldibromosilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane Triethoxy hydrosilane, tri bromine hydrosilane, trimethoxy hydrosilane, isopropoxycarbonyl hydrosilane, tri t- butoxy hydrosilane, vinyl trichlorosilane, vinyl trimethoxy bromine silane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl triisopropoxysilane, vinyl tri t
-Butoxysilane, trifluoropropyltrichlorosilane, trifluoropropyltribromosilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, trifluoropropyltriisopropoxysilane, trifluoropropyltri-butoxysilane, γ- Glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ
Glycidoxypropyltriisopropoxysilane, γ
-Glycidoxypropyltri-t-butoxysilane, γ-
Methacryloxypropylmethyldimethoxysilane, γ
-Methacryloxypropylmethyldiethoxysilane,
γ-methacryloxypropyltrimethoxysilane, γ
-Methacryloxypropyltriisopropoxysilane, γ-methacryloxypropyltri-t-butoxysilane, γ-aminopropylmethyldimethoxysilane, γ
-Aminopropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropyltri-t-butoxysilane, γ-mercaptopropylmethyldimethoxysilane ,
γ-mercaptopropylmethyldiethoxysilane, γ-
Mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltriisopropoxysilane, γ-mercaptopropyltri-t-butoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3, 4
-Epoxycyclohexyl) ethyltriethoxysilane and their partial hydrolysates or mixtures thereof can be used.

In order to ensure good hardness and smoothness of the silicone resin film, it is preferable to contain 10 mol% or more of the three-dimensionally crosslinked siloxane. In order to provide sufficient flexibility of the resin film while securing good hardness and smoothness, it is preferable to contain 60 mol% or less of the two-dimensional crosslinked siloxane. In order to increase the rate at which the organic group bonded to the silicon atom of the silicone molecule is replaced with a hydroxyl group by photoexcitation, use is made of a silicone in which the organic group bonded to the silicon atom of the silicone molecule is an n-propyl group or a phenyl group. Is preferred. An organopolysilazane compound having a silazane bond can be used instead of the silicone having a siloxane bond.

Titanium oxide is most preferred as the photocatalyst particles. In addition, ZnO, SnO ₂ , SrTi
Metal oxides such as O ₃ , WO ₃ , Bi ₂ O ₃ , and Fe ₂ O ₃ are mentioned. It is considered that, since a metal element and oxygen are present on the surface, a hydroxyl group (OH ⁻ ) is easily adsorbed on the surface, and therefore, it is easy to exhibit hydrophilicity.

Examples of the particles for suppressing the redox action of the photocatalyst particles include alkali metals, alkaline earth metals, alumina, silica, zirconia, antimony oxide, amorphous titanium oxide, aluminum, and manganese.

[0023]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 3 is a perspective view showing a state where the anti-fog seal according to the present invention is applied to a mirror, FIG. 4 is a perspective view showing a state where the anti-fog seal is applied to a side window of an automobile, and FIG. Perspective view of the state to apply,
6A to 6D are cross-sectional views of the anti-fog seal.

The anti-fog seal is cut according to the shape of the object to be stuck, and an example of its cross-sectional structure is as shown in FIG.
An adhesive layer 2 is provided on the back side of the transparent resin sheet 1, and a release paper 3 is further provided thereon. In addition, the adhesive layer 2
May not be provided on the entire back surface of the transparent resin sheet 1 but may be provided so as to draw a continuous circle, for example. By doing so, it is easy to peel off, and the coloring caused by the adhesive can be suppressed.

The transparent resin sheet 1 contains photocatalyst particles.

The cross-sectional structure shown in FIG. 6B has a hydrophilic surface layer containing photocatalyst particles and particles for suppressing the redox action of the photocatalyst particles on the surface of a base sheet 4 made of a transparent resin containing no photocatalyst particles. 5 are formed.

In the cross-sectional structure shown in FIG. 6C, a protective layer 6 containing particles for suppressing the redox action of the photocatalyst particles is formed on a base sheet 4 made of a transparent resin containing no photocatalyst particles. On the layer 6, a hydrophilic surface layer 5 containing photocatalyst particles is formed. By providing the protective layer 6 between the base sheet 4 and the hydrophilic surface layer 5 as described above, even when the base sheet 4 contains a plasticizer, the hydrophilicity of the photocatalyst particles is adversely affected by the plasticizer. I do not receive.

In the sectional structure shown in FIG. 6D, a colored layer 7 is provided between the transparent resin sheet 1 and the adhesive layer 2. By providing the coloring layer 7 in this manner, deterioration due to ultraviolet rays can be prevented.

Further, instead of mixing the particles for suppressing the oxidation-reduction action of the photocatalyst particles with the photocatalyst particles or providing the protective layer 6, as shown in FIG. It may be covered with a protective film 9 for suppressing the redox action. In this case, in order to enhance the hydrophilizing effect of the photocatalyst particles 8, it is preferable that the surface is etched with an alkali or the like so that the photocatalyst particles 8 are directly exposed to the outside air.

Example 1 Methyltrimethoxysilane,
A mixed solution of dimethyldimethoxysilane and acidic peptized titanium oxide sol was prepared. Here, the mixing ratio of methyltrimethoxysilane and dimethyldimethoxysilane was 7: 3 by weight, and the ratio of titanium oxide sol was 100
0, 5, 10, 50, and 80 respectively. And polyethylene terephthalate (PET)
After spraying an aqueous solution of sodium nitrate onto the film substrate, each of the above mixed liquids is applied and heat-treated at 100 ° C. to form a mixed layer of titanium oxide and silicone (having a thickness of 0.1 μm).
1 μm). An adhesive is applied to the back surface of the PET film obtained as described above, and is adhered to the surface of a commercially available mirror,
Ultraviolet rays of 0.5 mW / cm ² were irradiated for 5 hours. The results are shown in the following (Table 1).

[0031]

[Table 1]

Example 2 A protective layer made of a silicone resin was formed to a thickness of 3 μm on a polyethylene terephthalate (PET) film substrate, and the same mixture as in Example 1 was applied on this protective layer. Then, a mixed layer of titanium oxide and silicone was formed with a thickness of 0.1 μm. An adhesive is applied to the back surface of the PET film obtained as described above, adhered to the surface of a commercially available mirror, and irradiated with an ultraviolet ray of 0.5 mW / cm ² for 5 minutes.
Irradiated for hours. The results were the same as in the above (Table 1).

Example 3 An aluminum vapor-deposited film was formed on a polyethylene terephthalate (PET) film substrate. The thickness of the deposited aluminum film was 1 μm and 0.05 μm. The former acts as a mirror because it is thick, and the latter acts as a heat ray reflective film because it is thin. On the above aluminum deposition film,
The same mixed solution as in Example 1 was applied to form a mixed layer of titanium oxide and silicone with a thickness of 0.1 μm. An adhesive was applied to the back surface of the PET film obtained as described above, adhered to the surface of a commercially available mirror, and irradiated with ultraviolet rays of 0.5 mW / cm ² for 5 hours. The results were the same as in the above (Table 1).

[0034]

As described above, according to the present invention, it is possible to easily impart hydrophilicity to the surfaces of existing mirrors, window glasses, goggles, etc. The hydrophilicity can be maintained over the entire surface, and the moisture adhering to the surface becomes a thin water film, so that the drying is quick.

Further, according to the present invention, the surface layer of the anti-fog seal adhered to the surface of a mirror, a window glass, goggles or the like contains photocatalyst particles or contains particles for suppressing the redox action of the photocatalyst particles. Since the layer is provided as a base layer of the layer made of the photocatalyst particles, not only the antifogging effect but also the portion in contact with the resin layer containing the photocatalyst particles or the photocatalyst particle layer does not corrode, deteriorate or discolor.

Further, according to the present invention, the seal is provided with hydrophilicity because the seal is peelable and can be cut into an arbitrary shape.
A sticker can be stuck to a place where fogging is required, which is extremely convenient.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a process of imparting hydrophilicity to the surface of a silicone resin containing photocatalyst particles.

FIG. 2 is a diagram illustrating a process of imparting hydrophilicity to a surface layer made of photocatalytic particles.

FIG. 3 is a perspective view showing a state in which the anti-fog seal according to the present invention is applied to a mirror.

FIG. 4 is a perspective view showing a state in which the anti-fog seal is applied to a side window of an automobile.

FIG. 5 is a perspective view showing a state in which the anti-fog seal is applied to goggles.

6A to 6D are cross-sectional views of an anti-fog seal.

FIG. 7 is a diagram illustrating a process of exposing photocatalytic particles by etching.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hydrophilic resin sheet, 2 ... Adhesive layer, 3 ... Release paper, 4
... Base sheet, 5 ... Hydrophilic surface layer, 6 ... Protective layer, 7 ...
Colored layer, 8 photocatalyst particles, 9 protective film.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B32B 5/16 B32B 5/16 C03C 17/32 C03C 17/32 C (72) Inventor Toshiya Watanabe Kokurakita, Kitakyushu-shi, Fukuoka 2-1-1 Nakajima-ku, Toto Toki Kiki Co., Ltd. (72) Inventor Atsushi Kitamura 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Totoki Kiki Co., Ltd.

Claims (5)

[Claims] 1. A resin sheet having a hydrophilic surface layer containing photocatalyst particles formed on a front surface thereof, an adhesive layer provided on a back surface thereof, and a photocatalyst particle formed between the resin sheet and the surface layer. An antifogging seal provided with a protective layer for preventing deterioration of a resin sheet due to an oxidation-reduction reaction. 2. The anti-fog seal according to claim 1, wherein
An anti-fog seal, wherein the protective layer is formed by applying a sodium salt solution to the surface of a resin sheet. 3. The anti-fog seal according to claim 1, wherein
The anti-fog seal, wherein the protective layer is an aluminum vapor-deposited film. 4. An adhesive layer is provided on the back surface side of the resin sheet, and photocatalyst particles are contained in the resin sheet. An anti-fog seal characterized by having a protective film formed thereon for prevention. 5. The anti-fog seal according to claim 4, wherein
An anti-fog seal, wherein a protective film on a surface of the photocatalyst particles exposed to the outside air is removed.