JP2011116038A - Laminate and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate having photo-catalytic properties and a method for production the same, wherein detachment of photo-catalyst particles is prevented without deteriorating a plastic substrate and yet adhesion of each layer is excellent. <P>SOLUTION: A laminate 10 and its production process is characterized in that the laminate 10 includes: a plastic substrate 11; a deposition layer 12 formed on the plastic substrate 11 by depositing oxide ceramics; an anchor coat layer 13 formed on the deposition layer 12 and containing an alkali metal silicate; and a photo-catalyst layer 14 formed on the anchor coat layer 13 and containing titanium dioxide and the alkali metal silicate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laminate having photocatalytic activity and a method for producing the same.

Known as a method for imparting photocatalytic activity to ceramics such as ceramics and glass, and inorganic bases made of inorganic heat-resistant materials such as metals, is a method of coating the surface of inorganic bases with a photocatalytic layer made of titanium dioxide. ing. In order to maintain the photocatalytic ability, it is important to maintain good adhesion between the photocatalytic layer and the inorganic base material.
As a method for forming a photocatalyst layer on the surface of an inorganic base material, for example, Non-Patent Document 1 discloses a method of baking titanium dioxide on an inorganic base material at a high temperature of 400 ° C. or higher, and sometimes 800 ° C. or higher. ing.

On the other hand, an organic base material made of an organic material such as plastic is inferior in heat resistance to an inorganic base material, so that a photocatalytic layer is formed on the surface of the organic base material by baking titanium dioxide at a high temperature. It was difficult.
Therefore, in the case of an organic base material, usually, a solution in which titanium dioxide is dispersed in a solvent is applied to the surface of the organic base material and dried to form a photocatalyst layer.
However, since titanium dioxide exhibiting photocatalytic ability has an organic substance resolving power, when the photocatalytic layer is directly formed on the organic base material, the organic base material is likely to deteriorate. Therefore, in many cases, an intermediate layer is provided between the organic base material and the photocatalyst layer to prevent deterioration of the organic base material.

For example, Patent Document 1 discloses that photocatalyst particles are prevented from falling off, and the photocatalyst particles are coated with water glass for the purpose of preventing the base material from being damaged by sintering and fixing the photocatalyst particles at a high temperature on the base material. A method of forming a photocatalyst layer by mixing a hard-to-decompose binder such as, or providing an intermediate layer made of a hard-to-decompose binder such as water glass between the substrate and the photocatalyst layer. ing.
Patent Document 2 discloses that a silica film is formed on a polymer sheet as an intermediate layer by a physical vapor deposition method, a chemical vapor deposition method, or a method of coating silica sol mixed with a silicone resin, and a photocatalyst is formed on the intermediate layer. A method of forming a layer is disclosed.

JP-A-7-171408 JP 10-309773 A

Akira Fujishima, et al. “Introductory Visual Science Photocatalytic Mechanism”, published by Nihon Jitsugyo Publishing Co., Ltd., 2000, p142

As described in Patent Document 1, the method of forming a photocatalyst layer by mixing a photocatalytic particle with a hard-to-decompose binder is an organic group having low heat resistance such as a plastic substrate without dropping the photocatalyst particle. It is widely used as a method for forming a photocatalytic layer on a material. However, since the photocatalytic layer is directly formed on the organic base material, the problem of deterioration of the organic base material due to the photocatalytic layer cannot be solved.
Patent Document 1 also describes a method of providing an intermediate layer made of a hardly decomposable binder between the base material and the photocatalyst layer in order to prevent the organic base material from deteriorating. Adhesion between the material and the intermediate layer was not sufficient and sometimes peeled off.

When the intermediate layer is formed by physical vapor deposition or chemical vapor deposition as described in Patent Document 2, the adhesion between the base material and the intermediate layer is good, but the adhesion between the intermediate layer and the photocatalyst layer is insufficient. Met. On the other hand, when the intermediate layer is formed by the method of coating silica sol, the adhesion between the intermediate layer and the photocatalyst layer is improved, but the adhesion between the substrate and the intermediate layer is insufficient.
Thus, it was difficult to provide an intermediate layer having excellent adhesion to both the organic base material and the inorganic photocatalyst layer.

  The present invention has been made in view of the above circumstances, and provides a laminate having a photocatalytic ability that prevents photocatalyst particles from falling off without deteriorating a plastic substrate and has excellent adhesion between layers, and a method for producing the same. The purpose is to do.

  As a result of intensive studies, the present inventors have found that when forming a photocatalyst layer, the photocatalyst particles can be prevented from falling off by mixing a binder such as water glass with the photocatalyst particles. It paid attention that it can prevent the deterioration of the base material by a photocatalyst, maintaining favorable adhesiveness of a base material and a vapor deposition layer by providing. Therefore, by further providing an anchor coat layer that exhibits excellent adhesion to both layers between the photocatalyst layer and the vapor deposition layer provided on the substrate, the photocatalyst layer and the vapor deposition layer are firmly adhered to each other. As a result, it has been found that the photocatalyst particles can be prevented from falling off without deteriorating the base material, and the adhesion of each layer can be sufficiently maintained. Specifically, the vapor deposition layer is a layer made of an oxide-based ceramic, and the anchor coat layer contains the same kind of binder as the binder contained in the photocatalyst layer, so that the anchor coat layer is formed of the vapor deposition layer and the photocatalyst layer. The inventors have found that the adhesiveness is excellent with respect to both, and have completed the present invention.

That is, the laminate of the present invention comprises a plastic substrate, a vapor deposition layer formed on the plastic substrate by vapor deposition of an oxide-based ceramic, and an alkali metal silicate formed on the vapor deposition layer. An anchor coat layer containing a salt and a photocatalyst layer containing titanium dioxide and an alkali metal silicate salt formed on the anchor coat layer are provided.
The oxide ceramic preferably contains silicon dioxide.
Furthermore, it is preferable that the alkali metal silicate contained in the anchor coat layer is sodium silicate or potassium silicate.
Moreover, it is preferable that the alkali metal silicate contained in the photocatalyst layer is sodium silicate.

  Further, the method for producing a laminate of the present invention includes a step of forming an anchor coat layer by applying an aqueous solution containing an alkali metal silicate salt onto a deposited layer made of an oxide-based ceramic deposited on a plastic substrate. And a step of applying an aqueous dispersion containing titanium dioxide and an alkali metal silicate to form a photocatalyst layer on the anchor coat layer.

  ADVANTAGE OF THE INVENTION According to this invention, the laminated body which has the photocatalytic ability which prevented drop-off | omission of the photocatalyst particle and was excellent in the adhesiveness of each layer, and a plastic substrate base material can be provided.

It is sectional drawing which shows an example of the laminated body of this invention. It is a schematic diagram which shows typically the surface state of a photocatalyst layer.

Hereinafter, an example of the laminate of the present invention will be described with reference to FIG.
The laminated body 10 in this example includes a plastic substrate 11, a vapor deposition layer 12 formed on the plastic substrate 11, an anchor coat layer 13 formed on the vapor deposition layer 12, and the anchor coat layer 13. And a photocatalyst layer 14 formed on the substrate.
In FIG. 1, for the convenience of explanation, the dimensional ratio is different from the actual one.

<Plastic base material>
Examples of the material of the plastic substrate 11 include polyesters such as polyethylene terephthalate and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene; polyamides such as nylon 6 and nylon 6,6. Among these, polyester is preferable from the viewpoint of excellent heat resistance and dimensional stability.

The shape of the plastic substrate 11 is not particularly limited, and may be a thin film shape such as a film or a sheet, or may be a three-dimensional shape formed by a bag shape or a mold after bag making.
When the shape of the plastic substrate 11 is a film, the thickness is preferably 5 to 2000 μm, and more preferably 10 to 1000 μm. If the thickness of the plastic substrate 11 is 5 μm or more, the plastic substrate is not too soft and wrinkles and the like are less likely to occur, so that the vapor deposition layer 12 formed on the plastic substrate 11 is less likely to be spotted. On the other hand, if the thickness of the plastic substrate 11 is 2000 μm or less, it becomes easy to obtain the laminate 10 having sufficient flexibility, and therefore the laminate 10 can be easily applied to various uses.

<Deposition layer>
The vapor deposition layer 12 is a layer formed by vapor-depositing an oxide ceramic on the plastic substrate 11. By using oxide ceramics, it is possible to deposit on the plastic substrate 11 extremely uniformly and stably. Furthermore, since a transparent vapor deposition layer is obtained easily, it is suitable when using the laminated body 10 for the use for which transparency is calculated | required.
Therefore, the vapor deposition layer 12 is excellent in adhesiveness with the plastic substrate 11. Further, since the vapor deposition layer 12 has a blocking property that prevents the organic substance resolution of the photocatalyst of the photocatalyst layer 14 described later from acting on the plastic substrate 11, the plastic substrate 11 can be prevented from being deteriorated by the photocatalyst layer 14. .

  From the viewpoint of excellent uniformity, stability, and transparency of the deposited film, the oxide ceramics of the deposited layer 12 is preferably silicon dioxide or aluminum oxide. Furthermore, silicon dioxide and aluminum oxide are preferable from the viewpoint of excellent adhesion to the anchor coat layer 13 described later. Among them, the same silicate compound type silicon dioxide as the alkali metal silicate contained in the anchor coat layer 13 is used. Particularly preferred. In addition, not only single deposition of silicon dioxide alone, but also one containing silicon dioxide, for example, even in binary deposition of two or more with other oxide ceramics such as aluminum oxide, anchors are similarly used. It is preferable from the point which is excellent in adhesiveness with a coat layer.

  The thickness of the vapor deposition layer 12 is preferably 10 to 200 nm, and more preferably 20 to 100 nm. If the thickness of the vapor deposition layer 12 is 10 nm or more, a sufficient barrier property can be exhibited, so that the plastic substrate 11 can be prevented from being deteriorated by the photocatalytic ability. On the other hand, if the thickness of the vapor deposition layer 12 is 200 nm or less, the vapor deposition layer 12 is unlikely to crack.

<Anchor coat layer>
The anchor coat layer 13 is a layer containing an alkali metal silicate salt. Since this alkali metal silicate is also contained as a binder in the photocatalyst layer 14 described later, the anchor coat layer 13 is excellent in adhesion to the photocatalyst layer 14. Further, as described above, the alkali metal silicate is classified into the same silicate compound system when the oxide ceramics constituting the vapor deposition layer 12 is silicon dioxide or includes silicon dioxide. It also has excellent adhesion to the layer 12.

  Examples of the alkali metal silicate contained in the anchor coat layer 13 include sodium silicate and potassium silicate. The alkali metal silicate salt contained in the anchor coat layer 13 may be the same compound as the alkali metal silicate salt contained in the photocatalyst layer 14 described later, or may be a different compound. The same compound is preferable in that the adhesion between the layer 13 and the photocatalyst layer 14 is particularly excellent.

  The thickness of the anchor coat layer 13 is preferably 0.01 to 2.00 μm, and more preferably 0.05 to 1.00 μm. If the thickness of the anchor coat layer 13 is 0.01 μm or more, sufficient adhesion to the vapor deposition layer 12 and the photocatalyst layer 14 can be exhibited, so that the vapor deposition layer 12 and the photocatalyst layer 14 adhere more firmly. On the other hand, even if the thickness of the anchor coat layer 13 exceeds 2.00 μm, the adhesion effect reaches its peak. From the viewpoint of reducing the manufacturing cost and the thickness of the entire laminated body 10, it is sufficient that the upper limit of the thickness of the anchor coat layer 13 is 2.00 μm or less.

<Photocatalyst layer>
The photocatalyst layer 14 is a layer containing titanium dioxide and an alkali metal silicate. When the photocatalyst layer 14 contains an alkali metal silicate salt as a binder, the titanium dioxide particles can be prevented from falling off, and excellent photocatalytic ability can be imparted to the resulting laminate 10. In addition, the adhesion with the above-described anchor coat layer 13 is also excellent.

Titanium dioxide is not particularly limited as long as it has photocatalytic activity, but it is preferable to use titanium dioxide having an average particle diameter of 0.005 to 2.000 μm. Titanium dioxide includes anatase type and methyl type crystal systems, and anatase type titanium dioxide is particularly preferable because of its excellent photocatalytic activity. In addition, titanium dioxide that can obtain photocatalytic activity with visible light is also suitable.
Furthermore, it is preferable to use an aqueous dispersion in which titanium dioxide is dispersed in water in order to make it easier to form the photocatalyst layer 14 on the anchor coat layer 13. As an aqueous dispersion of titanium dioxide, for example, “MPT-422” manufactured by Ishihara Sangyo Co., Ltd. is suitable.

Examples of the alkali metal silicate contained in the photocatalyst layer 14 include sodium silicate and potassium silicate. In order to make it easier to form the photocatalyst layer 14 on the anchor coat layer 13, like the alkali metal silicate contained in the anchor coat layer 13, sodium silicate or potassium silicate which is an alkali metal silicate is water. It is preferable to use an aqueous solution dissolved in the aqueous solution.
Among these, sodium silicate, particularly an aqueous solution in which sodium silicate is dissolved in water, so-called water glass, is particularly preferable in that titanium dioxide can sufficiently exhibit photocatalytic activity as described later.
The reason why sodium silicate is preferable is as follows.

  Although the titanium dioxide particles are uniformly dispersed in the photocatalyst layer 14, as shown in FIG. 2A, when sodium silicate 14b is used as the alkali metal silicate salt, the titanium dioxide particles are present on the surface of the photocatalyst layer 14. The titanium dioxide particles 14a to be exposed tend to be exposed from the surface of the photocatalyst layer 14. As a result, the photocatalytic ability is easily exhibited sufficiently. On the other hand, as shown in FIG. 2B, when potassium silicate 14c is used as the alkali metal silicate, the titanium dioxide particles 14a existing on the surface of the photocatalyst layer 14 are not easily exposed from the surface of the photocatalyst layer 14. There is a tendency. Therefore, the photocatalytic ability may be hardly exhibited as compared with the case where sodium silicate is used.

  The mass ratio of titanium dioxide and alkali metal silicate is preferably titanium dioxide: alkali metal silicate = 1.5: 1.0-10.0: 1.0, and 1.8: 1.0-6. 0: 1.0 is more preferable. When the ratio of the alkali metal silicate is too large, the photocatalytic ability is not sufficiently exhibited. On the other hand, if the proportion of the alkali metal silicate is too small, the adhesion between the photocatalyst layer 14 and the anchor coat layer 13 tends to be lowered.

  The photocatalyst layer 14 may be composed only of titanium dioxide and alkali metal silicate, or may contain other components within a range not impairing the effects of the present invention. Specifically, platinum, palladium or the like may be blended, or silver or copper may be blended in order to sufficiently develop the photocatalytic ability even with weak light. Moreover, in order to express photocatalytic activity under visible light, a trace amount of ruthenium or chromium may be blended, or nitrogen may be doped.

  The thickness of the photocatalyst layer 14 is preferably 1 to 10 μm, and more preferably 2 to 5 μm. When the thickness of the photocatalyst layer 14 is 1 μm or more, the binder effect due to the alkali metal silicate is sufficiently exhibited, and the adhesion with the anchor coat layer 13 can be maintained well. On the other hand, if the thickness of the photocatalyst layer 14 is 10 μm or less, insufficient drying and uneven drying are unlikely to occur, and the titanium dioxide particles can be prevented from falling off.

<Others>
The laminate 10 of the present invention may be composed of only a plastic substrate 11, a vapor deposition layer 12, an anchor coat layer 13, and a photocatalyst layer 14, or the plastic substrate vapor deposition layer 12 may be formed as necessary. You may provide another layer in the surface on the opposite side to the formed side. However, if another layer is provided on the photocatalyst layer 14, it becomes difficult for the laminate 10 to exhibit sufficient photocatalytic activity. Therefore, it is preferable not to provide another layer on the photocatalyst layer 14.
An intermediate layer may be provided between the plastic substrate 11 and the vapor deposition layer 12 for the purpose of improving the adhesion between the plastic substrate 11 and the vapor deposition layer 12. A protective layer may be provided between the vapor deposition layer 12 and the anchor coat layer 13 for the purpose of protecting the vapor deposition layer 12. In the present invention, the intermediate layer and the protective layer are included in the vapor deposition layer 12.

<Method for producing laminate>
Hereinafter, the manufacturing method of the laminated body 10 is demonstrated.
First, the anchor coat layer 13 is formed on the vapor deposition layer 12 made of oxide ceramics deposited on the plastic substrate 11.
The plastic substrate 11 on which the deposited layer 12 on which the oxide-based ceramic is deposited is formed as a commercially available product. Specifically, as polyethylene terephthalate on which oxide-based ceramics are deposited, a film in which silicon dioxide is deposited on polyethylene terephthalate (“Techbarrier VX” manufactured by Mitsubishi Plastics, Inc.), a film on which aluminum oxide is deposited on polyethylene terephthalate (East Cello “TL-PET-H # 12” manufactured by Co., Ltd.), a film obtained by binary deposition of silicon dioxide and aluminum oxide on polyethylene terephthalate (“Ecosia VE500” manufactured by Toyobo Co., Ltd., etc.) are also suitable. Instead of this, a nylon 6 film deposited with oxide ceramics, a nylon 66 film deposited with oxide ceramics, or the like can also be suitably used.
Alternatively, an oxide ceramic may be deposited on the plastic substrate 11 by physical vapor deposition or chemical vapor deposition to form the vapor deposition layer 12.

The anchor coat layer 13 can be formed by diluting the above-mentioned alkali metal silicate with water to prepare an aqueous solution for the anchor coat layer, applying the aqueous solution onto the vapor deposition layer 12, and drying. Further, when water glass in which sodium silicate is dissolved in water is used as the alkali metal silicate salt, the water glass itself may be applied as an aqueous solution for the anchor coat layer on the vapor deposition layer 12, but the desired thickness. In order to easily form the anchor coat layer 13, it is preferable to further dilute the water glass with water and use this as an aqueous solution for the anchor coat layer.
The concentration of the aqueous solution for the anchor coat layer is not particularly limited, but in order to easily form the anchor coat layer 13 having a desired thickness, the content of the alkali metal silicate in the aqueous solution of 100% by mass is 3 to 10% by mass. It is preferable to prepare so that it may become%.

The application method of the aqueous solution for the anchor coat layer may be any method that can be applied uniformly and uniformly on the vapor deposition layer 12, and the gravure coat method is the most common application method, but the present invention is not limited to this. . For example, a micro gravure coating method, a comma coating method, a roll coating method, a reverse roll coating method, a bar coating method, a kiss coating method, a flow coating method, a gap coating method, etc. may be applied as necessary.
Moreover, it does not restrict | limit especially as a drying method, However, Usually, it is preferable to heat at 50-100 degreeC with heating methods, such as hot air drying. The heating time is preferably within 2 minutes.

Next, the photocatalyst layer 14 is formed on the anchor coat layer 13. The photocatalyst layer 14 is prepared by mixing the above-described titanium dioxide and alkali metal silicate with other components as necessary, and dispersing this in water to prepare an aqueous dispersion for the photocatalyst layer. It can be formed by applying the body on the anchor coat layer 13 and drying.
From the viewpoint of ease of application on the anchor coat layer 13, when powdered titanium dioxide is used, it is preferable to disperse titanium dioxide in water. Moreover, you may use the aqueous dispersion which titanium dioxide disperse | distributed to water which can be obtained as a commercial item. On the other hand, it is preferable to use the alkali metal silicate dissolved in water, and it is particularly preferable to use water glass in which sodium silicate is dissolved in water. When an aqueous dispersion of titanium dioxide or an aqueous solution of alkali metal silicate is used, a mixture of these may be applied onto the anchor coat layer 13 as an aqueous dispersion for the photocatalyst layer. From the viewpoint of facilitating application by lowering the viscosity, it is preferable to further dilute the mixture with water and use this as an aqueous dispersion for the photocatalyst layer.

  The concentration of the aqueous dispersion for the photocatalyst layer is not particularly limited, but in order to easily form the photocatalyst layer 14 having a desired thickness, the content of titanium dioxide in 100% by mass of the aqueous dispersion is 2 to 30% by mass. The content of the alkali metal silicate is preferably 10 to 50% by mass.

In preparing the aqueous dispersion for the photocatalyst layer, the dispersion is performed with stirring and mixing so that the titanium dioxide and the alkali metal silicate are uniform using a disperser capable of effectively dispersing the fine particles in the medium. Examples of the disperser include dispersers such as an ultrasonic disperser, a ball mill, a roll mill, a bead mill, and a homogenizer.
When the dispersion of the titanium dioxide particles in the aqueous dispersion is insufficient, the titanium dioxide particles are likely to aggregate and settle. As a result, even if an aqueous dispersion for photocatalyst is applied on the anchor coat layer 13, a uniform and homogeneous photocatalyst layer may not be formed, and sufficient photocatalytic activity may not be exhibited. In addition, titanium dioxide particles may settle in the formed photocatalytic layer, and sufficient photocatalytic activity may not be exhibited.
In order to suppress sedimentation of titanium dioxide particles, it is preferable to apply an aqueous dispersion for the photocatalyst layer immediately after preparation. Moreover, even if the titanium dioxide particles are sufficiently dispersed, they may aggregate and settle over time. In order to prevent this, it is also effective to increase the viscosity of the aqueous dispersion or to prepare an aqueous dispersion for the photocatalyst layer so as to create an electrically stable state.

The application method of the aqueous dispersion for the photocatalyst layer may be any method that can be applied uniformly and homogeneously on the anchor coat layer 13, and various application methods exemplified above in the description of the application method of the aqueous solution for the anchor coat layer. Can be applied.
Moreover, it does not restrict | limit especially as a drying method, However, Usually, it is preferable to heat at 50-100 degreeC with heating methods, such as hot air drying. The heating time is preferably within 2 minutes.

The laminate 10 thus obtained has an excellent photocatalytic ability.
By the way, the photocatalytic ability has various actions such as an oxidizing action, an antibacterial action, a hydrophilizing action, and an antifouling action. For example, the photocatalytic ability can be evaluated using the oxidizing action as an index. Specifically, by monitoring the reaction of acetone generated by the oxidation action of isopropanol, it is possible to evaluate the susceptibility of the oxidation action, which is one of the photocatalytic capabilities, and the higher the value of acetone production rate, the greater the value. It means that it is excellent in oxidation action. According to this evaluation method, if the rate of acetone production 30 minutes after the start of the isopropanol oxidation reaction is 0.1 ppm / min or more, it can be determined that the photocatalytic activity has sufficient oxidation action, and the lamination of the present invention The body 10 meets this.
The method for evaluating the photocatalytic ability using the oxidation action of isopropanol as an index is as follows.

First, a sample having a size of 2 × 2 cm in length and width is cut out from the laminate, placed in a 300 mL photocatalytic capacity measurement cell, and sealed.
Next, a 200 W mercury-xenon lamp is irradiated into the cell to clean the inside of the cell and the sample surface.
Next, 0.1 μL of isopropanol is introduced into the cell using a liquid microsyringe, and left in the dark until the isopropanol reaches adsorption equilibrium.
Thereafter, ultraviolet light with an energy of 0.5 mW / cm ² is irradiated into the cell, and the gas in the cell is collected at regular intervals. The gas collected using gas chromatography is analyzed, and the amount of isopropanol reduced by the oxidation reaction of isopropanol by the photocatalyst represented by the following reaction formula (1) and the amount of acetone produced by the oxidation reaction are measured.
(CH ₃ ) ₂ CHOH + (1/2) O ₂ → (CH ₃ ) CO (CH ₃ ) + H ₂ O (1)

And the production amount of acetone 30 minutes after immediately after ultraviolet light irradiation is measured, and the production | generation rate of acetone is calculated | required from following formula (2).
Acetone production rate (ppm / min) = Acetone production (ppm) / 30 (min) (2)

The laminated body of this invention demonstrated above is equipped with the plastic base material mentioned above, a vapor deposition layer, an anchor coat layer, and a photocatalyst layer.
Since the vapor deposition layer is formed on the plastic substrate by the vapor deposition method, the adhesion between the plastic substrate and the vapor deposition layer is good. In addition, since the vapor deposition layer is interposed between the plastic substrate and the photocatalyst layer, deterioration of the plastic substrate due to the organic matter resolution of the photocatalyst can be prevented.
Since the photocatalyst layer contains an alkali metal silicate as a binder, titanium dioxide can be prevented from falling off. Therefore, the laminate of the present invention has an excellent photocatalytic ability.

When the oxide ceramics constituting the vapor deposition layer is silicon dioxide, the anchor coat layer contains the same silicate compound-based alkali metal silicate, and thus has excellent adhesion to the vapor deposition layer.
Moreover, since the anchor coat layer contains the same alkali metal silicate as the binder in the photocatalyst layer, the anchor coat layer also has excellent adhesion to the photocatalyst layer.
Thus, by providing the anchor coat layer which shows the adhesiveness outstanding with respect to these both layers between a vapor deposition layer and a photocatalyst layer, a vapor deposition layer and a photocatalyst layer adhere | attach firmly. Therefore, the laminate of the present invention has excellent adhesion between layers and is difficult to delaminate.

  The laminate of the present invention can be suitably used as a packaging bag, wallpaper or the like. Moreover, you may stick and use on a window glass, wall material, etc. via an adhesive. Furthermore, the laminated body obtained by using the plastic base material processed into the desired shape and forming each layer mentioned above on this plastic base material surface can also be used as various articles | goods.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited by the following description.
Here, the evaluation method implemented by each Example and the comparative example is shown below.

(1) Evaluation of adhesion The cellophane tape (manufactured by Nichiban Co., Ltd.) was attached to the surface of the laminate on the photocatalyst layer side, and then the peeling operation was performed to evaluate the adhesion of each layer.

(2) Measurement of photocatalytic ability A sample having a size of 2 × 2 cm in length and width was cut out from the laminate, placed in a photocatalytic ability measuring cell having a capacity of 300 mL, and sealed.
Next, a 200 W mercury-xenon lamp was irradiated into the cell to clean the inside of the cell and the sample surface.
Next, 0.1 μL of isopropanol was introduced into the cell using a liquid microsyringe and left in the dark until isopropanol reached adsorption equilibrium.
Thereafter, ultraviolet light having an energy of 0.5 mW / cm ² was irradiated into the cell, and the gas in the cell was collected 30 minutes after the ultraviolet light irradiation. The gas collected using gas chromatography was analyzed, the amount of acetone produced by the oxidation reaction of isopropanol was measured, the production rate of acetone was determined from the following formula (2), and this was used as an index of photocatalytic activity.
Acetone production rate (ppm / min) = Acetone production (ppm) / 30 (min) (2)

[Example 1]
A sodium silicate solution (manufactured by Kanto Chemical Co., Inc., reagent grade 1, SiO ₂ content 35 to 38 mass%, Na ₂ O content 17 to 19 mass%) is diluted 9 times with water, and the anchor coat layer An aqueous solution was prepared.
Separately, 90 g of an aqueous dispersion of titanium dioxide (“MPT-422” manufactured by Ishihara Sangyo Co., Ltd., TiO ₂ content 18.3% by mass), 10 g of sodium silicate solution, and 80 g of water were mixed with a homogenizer (M The mixture was stirred for 5 minutes with “CLEAMIX” manufactured by Technic Co., Ltd. to prepare an aqueous dispersion for a photocatalyst layer in which titanium dioxide was uniformly dispersed.

A film ("Tech Barrier VX" manufactured by Mitsubishi Plastics Co., Ltd., thickness 12 μm) in which a vapor deposition layer formed by physical vapor deposition of silicon dioxide was formed on polyethylene terephthalate as a plastic substrate was used. On the deposited layer of this film, the previously prepared aqueous solution for anchor coat layer was subjected to the Mayer bar No. 5 so that the thickness after drying was 0.3 μm. 4 was applied and dried at 80 ° C. for 30 seconds to form an anchor coat layer.
Next, on the anchor coat layer, the previously prepared aqueous dispersion for the photocatalyst layer was subjected to a Meyer bar No. 5 so that the thickness after drying was 3 μm. 24 was applied and dried at 80 ° C. for 30 seconds to form a photocatalyst layer to obtain a laminate. Table 1 shows components constituting the vapor deposition layer, the anchor coat layer, and the photocatalyst layer.
The resulting laminate was evaluated for adhesion and photocatalytic activity. The results are shown in Table 1.

[Example 2]
Except for using a film (“TL-PET-H # 12” manufactured by Tosero Co., Ltd., thickness 12 μm) on which polyethylene oxide is physically deposited on polyethylene terephthalate, the same procedure as in Example 1 was performed. To obtain a laminate.
The resulting laminate was evaluated for adhesion and photocatalytic activity. The results are shown in Table 1.

[Example 3]
Instead of a sodium silicate solution, a potassium silicate solution (manufactured by Wako Pure Chemical Industries, Ltd., content of K ₂ SiO ₃ of 27 to 29% by mass) is set to a pH equivalent to that of an aqueous sodium hydroxide solution. An aqueous solution for an anchor coat layer was prepared by diluting with water in the same manner as in Example 1 except that potassium prepared to pH = 12.5 was used. A laminate was obtained in the same manner as in Example 1 except that the obtained aqueous solution for anchor coat layer was used.
The resulting laminate was evaluated for adhesion and photocatalytic activity. The results are shown in Table 1.

[Example 4]
An aqueous dispersion for a photocatalyst layer was prepared in the same manner as in Example 1 except that 10 g of potassium silicate solution was used instead of 10 g of sodium silicate solution. A laminate was obtained in the same manner as in Example 1 except that the obtained aqueous dispersion for the photocatalyst layer was used.
The resulting laminate was evaluated for adhesion and photocatalytic activity. The results are shown in Table 1.

[Comparative Example 1]
A laminate was obtained in the same manner as in Example 1 except that no anchor coat layer was formed on the vapor deposition layer.
When the adhesion of the obtained laminate was evaluated, the adhesion was poor, and part of the laminate was adhered to the cellophane tape, resulting in delamination. As a result of measuring the thickness of the laminated body after the evaluation, it was 12 μm which was the same as the thickness of the film. Therefore, it is considered that delamination occurred between the vapor deposition layer and the photocatalyst layer.
Moreover, the photocatalytic ability was measured about the obtained laminated body. The results are shown in Table 1.

[Comparative Example 2]
Other than using oxide-ceramics-deposited film instead of polyethylene terephthalate film ("Espet T400" manufactured by Toyobo Co., Ltd., thickness 12 μm) whose surface was corona-treated only Obtained a laminate in the same manner as in Example 1.
When the adhesion of the obtained laminate was evaluated, the adhesion was poor, and part of the laminate was adhered to the cellophane tape, resulting in delamination. Separately, when the adhesion of a test piece prepared by forming only the anchor coat layer on the film used in Comparative Example 2 was evaluated, delamination occurred in the same manner. From these results, it is considered that the laminate obtained in Comparative Example 2 was generated between the corona-treated surface of the film and the anchor coat layer.
Moreover, the photocatalytic ability was measured about the obtained laminated body. The results are shown in Table 1.

[Comparative Example 3]
Instead of 10 g of the sodium silicate solution, 90 g of an aqueous colloidal silica dispersion (“Snowtex 30” manufactured by Nissan Chemical Industries, Ltd., SiO ₂ content 18.3% by mass) was used, and no water was added. Except for the above, an aqueous dispersion for a photocatalyst layer was prepared in the same manner as in Example 1. A laminate was obtained in the same manner as in Example 1 except that the obtained aqueous dispersion for the photocatalyst layer was used.
When the adhesion of the obtained laminate was evaluated, the adhesion was poor, and part of the laminate was adhered to the cellophane tape, resulting in delamination. Separately, when the adhesion of a test piece prepared by forming only the anchor coat layer on the vapor deposition layer of the film used in Comparative Example 3 was evaluated, no delamination occurred. From these results, it is considered that the laminate obtained in Comparative Example 3 was generated between the anchor coat layer and the photocatalyst layer.
Moreover, the photocatalytic ability was measured about the obtained laminated body. The results are shown in Table 1.

As is clear from Table 1, the laminates obtained in each example did not show delamination and had good adhesion between the layers. Moreover, the laminated body obtained by each Example had the outstanding photocatalytic ability. In particular, the laminates obtained in Examples 1 and 3 were very excellent in photocatalytic ability.
In addition, the photocatalytic ability of the laminate obtained in Example 2 was slightly lower than that of the laminate obtained in Example 1.
Moreover, although the photocatalytic ability of the laminated body obtained in Example 4 was not problematic, it was lower than the laminated bodies obtained in Examples 1 to 3. This is considered as follows.
That is, in Example 4, since potassium silicate was used as the alkali metal silicate contained in the photocatalyst layer, titanium dioxide present on the surface of the photocatalyst layer was compared to Examples 1 to 3 using sodium silicate. Difficult to expose. As a result, it is considered that the photocatalytic ability was not sufficiently exhibited as compared with Examples 1 to 3 and was lowered.

On the other hand, since the laminate obtained in Comparative Example 1 does not have an anchor coat layer provided between the vapor deposition layer and the photocatalyst layer, it seems that the adhesion between the vapor deposition layer and the photocatalyst layer is poor and delamination occurs. It was easy. In addition, after the formation of the photocatalyst layer and before the measurement of the photocatalytic activity, the titanium dioxide particles fall off due to delamination, resulting in a decrease in the amount of titanium dioxide particles in the photocatalytic layer, resulting in a decrease in photocatalytic activity. I think that the.
In the laminate obtained in Comparative Example 2, the vapor deposition layer is not provided between the plastic base material and the anchor coat layer. Therefore, it seems that the adhesion between the plastic base material and the anchor coat layer is poor, and delamination occurs. It was easy. In addition, after the formation of the photocatalyst layer and before the measurement of the photocatalytic activity, the titanium dioxide particles fall off due to delamination, resulting in a decrease in the amount of titanium dioxide particles in the photocatalytic layer, resulting in a decrease in photocatalytic activity. I think that the.
In the laminate obtained in Comparative Example 3, since the binder contained in the photocatalyst layer was colloidal silica, it was considered that the adhesion between the anchor coat layer and the photocatalyst layer was poor, and delamination was likely to occur. In addition, colloidal silica is inferior in binder performance as compared with alkali metal silicate, so that the titanium dioxide particles easily fall off, resulting in a decrease in photocatalytic ability.

10: laminate, 11: plastic substrate, 12: vapor deposition layer, 13: anchor coat layer, 14: photocatalyst layer, 14a: titanium dioxide particles, 14b: sodium silicate, 14c: potassium silicate.

Claims (5)

A plastic substrate;
A vapor deposition layer formed on the plastic substrate by vapor-depositing an oxide-based ceramic;
An anchor coat layer containing an alkali metal silicate salt formed on the vapor deposition layer;
And a photocatalyst layer containing titanium dioxide and an alkali metal silicate formed on the anchor coat layer.   The laminate according to claim 1, wherein the oxide-based ceramic contains silicon dioxide.   The laminate according to claim 1 or 2, wherein the alkali metal silicate contained in the anchor coat layer is sodium silicate or potassium silicate.   The laminate according to any one of claims 1 to 3, wherein the alkali metal silicate contained in the photocatalyst layer is sodium silicate. A step of forming an anchor coat layer by applying an aqueous solution containing an alkali metal silicate salt on a deposited layer made of an oxide-based ceramic deposited on a plastic substrate;
And a step of forming a photocatalyst layer by applying an aqueous dispersion containing titanium dioxide and an alkali metal silicate on the anchor coat layer.

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