JP5955984B2 - Base material with antiviral thin film - Google Patents

Description

  The present invention relates to a substrate with an antiviral thin film.

  From the viewpoint of hygiene, an article that may come into contact with microorganisms may be provided with a layer made of a metal such as silver, copper, or zinc, or a layer made of a photocatalyst such as titanium oxide. These metals and photocatalysts are known to have antibacterial properties. Said metal inactivates a microbe by substitution reaction with a cell membrane and a cytoplasm constituent substance, and exhibits an antibacterial effect. The above-mentioned photocatalyst exhibits an antibacterial effect by reactive oxygen species generated by ultraviolet irradiation attacking the cell walls and cell membranes of bacteria.

  It is also known that a photocatalyst and a metal are used in combination, cell walls of bacteria and the like are destroyed by the photocatalyst, and the antibacterial function by the metal is promoted. For example, Patent Document 1 describes that an antibacterial substrate is prepared by providing a photocatalyst layer containing titanium oxide on a base material and providing an island portion made of copper or the like on the photocatalyst layer. Yes.

  Patent Document 1 also describes that the produced antibacterial substrate is applied to an article that may come into contact with a virus.

  Patent Document 2 describes that metal oxide particles exhibit a photocatalytic action in the presence of copper divalent ions and chloride ions, and develop an allergen inactivating action based on this. Specifically, in Example 2 of Patent Document 2, a solution of a partial hydrolysis condensate of tetraethoxysilane and a dispersion of rutile titanium dioxide fine particles supporting a copper divalent salt are mixed to form a coating material. The production is described.

  Patent Document 3 describes that a virus is inactivated by electrons emitted when monovalent copper compound fine particles become divalent copper ions. In the example of Patent Document 3, a dispersion of monovalent copper compound fine particles is disclosed.

International Publication No. 2008/047810 JP 2011-111600 A JP 2010-239897 A

  As a result of examination by the present applicants, all of the antibacterial substrate described in Patent Document 1, the coating agent described in Patent Document 2, and the dispersion described in Patent Document 3 have sufficient antiviral properties. I found that there was no.

  In view of such circumstances, an object of the present invention is to provide a substrate with an antiviral thin film having excellent antiviral properties.

The present invention
A base material, and an antiviral thin film formed on the base material,
The antiviral thin film has a photocatalyst layer, and an island part mainly composed of a Cu-based material disposed in direct contact with the surface of the photocatalyst layer,
The photocatalyst layer contains anatase type titanium oxide,
A base material with an antiviral thin film having a molar ratio A which is a ratio of the number of moles of Cu (OH) _{2 to} the number of moles of all Cu atoms in the island portion is greater than 0.35 and less than or equal to 0.80;
I will provide a.

Another aspect of the present invention provides:
A base material, and an antiviral thin film formed on the base material,
The antiviral thin film has a photocatalyst layer, and an island part mainly composed of a Cu-based material disposed in direct contact with the surface of the photocatalyst layer,
The photocatalyst layer contains anatase type titanium oxide,
Anti-viral properties in which the amount of Cu (OH) ₂ supported is 70 ng / cm ² or more, calculated by dividing the amount of Cu (OH) ₂ in the island by the amount converted to metallic copper by the surface area of the layer. Substrate with thin film,
I will provide a.

  In the present specification, “main component” is used as a term indicating a component occupying 50% by mass or more, as is usual. Further, in this specification, the Cu-based material refers to a simple substance made of Cu element or a compound containing Cu element.

  According to the present invention, a substrate with an antiviral thin film having excellent antiviral properties can be provided.

Sectional drawing which shows an example of the typical structure of the base material with an antiviral thin film of this invention Sectional drawing which shows another example of the typical structure of the base material with an antiviral thin film of this invention Conceptual diagram showing how to form islands

  Hereinafter, the substrate with an antiviral thin film of the present invention will be described.

  First, the antiviral thin film formed on a base material is demonstrated. The antiviral thin film is a film that exhibits antiviral properties when irradiated with light. The antiviral thin film has a photocatalyst layer and an island part mainly composed of a Cu-based material.

  The photocatalyst layer generates charges (electrons or holes) when irradiated with light. The function of the photocatalyst layer as a photocatalyst is brought about by anatase-type titanium oxide. Further, the anatase type titanium oxide is preferably polycrystalline. The electric charge generated by the photocatalyst layer acts on an island portion mainly composed of a Cu-based material, and the photocatalyst layer and the island portion exhibit an antiviral effect as an antiviral thin film.

  The photocatalyst layer may consist essentially of titanium oxide. “Substantially” means that impurities that are inevitably mixed are not excluded.

  The titanium oxide contained in the photocatalyst layer may intentionally contain a small amount of a metal such as iron, aluminum or tungsten as a dopant. The generation of carriers in the photocatalyst layer is promoted by the dopant, and the photocatalytic activity of the photocatalyst layer is increased. The suitable metal content of the photocatalyst layer is 0.001 to 1.0% by mass. If the addition amount is less than this, the effect may not be obtained. If the addition amount is too large, the photocatalytic activity may be lowered due to disorder of the crystal structure of the photocatalyst layer and generation of recombination centers.

  The photocatalyst layer can be formed on the substrate by a known film formation method such as a chemical vapor deposition method (CVD method), a sputtering method, or a liquid phase method (for example, a sol-gel method). Among these, sputtering and CVD are recommended because a uniform film with a large area can be easily formed.

The islands are deposited in a scattered manner on the surface of the photocatalytic layer. The surface of the island is exposed and exhibits an antiviral effect when in contact with the virus. Specifically, the island part exhibits an antiviral action mainly derived from Cu (OH) ₂ contained in the island part. More specifically, when the molar ratio (molar ratio A), which is the ratio of the molar number of Cu (OH) _{2 to} the molar number of all Cu atoms in the island part, is more than 0.35 and not more than 0.80 The antiviral thin film exhibits good antiviral properties. The molar ratio A is preferably 0.37 to 0.70, and more preferably 0.38 to 0.60.

Further, the amount of Cu (OH) ₂ supported, calculated by dividing the weight of Cu (OH) ₂ in the island portion by the amount of metallic copper by the surface area of the photocatalyst layer, is, for example, 1 ng / cm ² or more. , preferably 4 ng / cm ² or more, more preferably 40 ng / cm ² or more, further preferably 70 ng / cm ² or more.

More preferably, the molar ratio (molar ratio B) of the sum of the number of moles of Cu (OH) _{2 and} the number of moles of CuO in the island to the number of moles of all Cu atoms in the island is 0.70 to 0. .95. That is, it is preferable that a part of Cu coexists in the state of Cu (Cu in a metal state) or Cu ₂ O in the island portion.

When the loading amount of Cu (OH) ₂ is 70 ng / cm ² or more, the antiviral thin film exhibits good antiviral properties as another aspect.

  The island portion may be substantially made of a Cu-based material. However, the island part may contain an additional metal (on a mass basis) in an amount smaller than that of the Cu-based material. Examples of the additive metal include at least one selected from tin (Sn), iron (Fe), zirconium (Zr), chromium (Cr), zinc (Zn), titanium (Ti), manganese (Mn), and the like. The addition of these metals can be expected to improve the corrosion resistance of the islands.

It is preferable that there are at least one island portion, for example, 100 to 3000, preferably 250 to 750, in an arbitrary region having an area of 1 × 1 μm ^{2 on} the surface of the photocatalyst layer. With this feature, the antiviral effect can be expressed uniformly in the plane.

  Moreover, the height of an island part is not specifically limited. From the viewpoint of avoiding catching of an object such as a dust cloth on the island part and enhancing the wear resistance of the island part, the maximum height of the island part is preferably 20 nm or less. On the other hand, from the viewpoint of ensuring antiviral properties, the maximum height of the island is preferably 1 nm or more. That is, from the above viewpoints, the maximum height of the island is preferably 1 to 20 nm, more preferably 1 to 10 nm, and particularly preferably 2 to 5 nm.

  As described in detail below, the island part is preferably formed on the photocatalyst layer by a sputtering method. In particular, the reactive sputtering method is preferable because it is easy to control the valence of Cu in the Cu-based material together with its distribution.

  The antiviral properties of the antiviral thin film are based on both the action of the photocatalytic layer and the action of the islands. More specifically, the antiviral property is exerted when the island part comes into contact with the virus, and the charge generated in the photocatalyst layer is transferred to the island part by irradiating the photocatalyst layer with light. It is considered that the antiviral action is significantly promoted. If both the antiviral property based on the island portion and the charge generation action based on the photocatalyst layer are combined in a well-balanced manner, the antiviral property of the entire antiviral thin film can be enhanced. From this point of view, the ratio of the total area of the island portion to the area of the antiviral thin film when observed along the thickness direction of the antiviral thin film, that is, when the antiviral thin film is observed from above the island portion. Is preferably 0.01 to 0.20, more preferably 0.03 to 0.15, and even more preferably 0.05 to 0.12.

In the base material with an antiviral thin film according to the present embodiment, island portions mainly composed of a Cu-based material are scattered on a photocatalyst layer mainly composed of titanium oxide. When the island part is formed as in the present embodiment, each area of the exposed surface of the photocatalyst layer partitioned by the island part (enclosed by a straight line connecting three adjacent island parts) is a certain area. (For example, 500 to 2000 nm ² ). Thereby, a photocatalyst layer can generate an electric charge effectively. Further, compared to a Cu-based material or the like doped with titanium oxide and taken into the titanium oxide crystal, the island portion of the present embodiment is sufficiently exposed to the outside air, and thus is easily in contact with the virus. In addition, unlike the film prepared by fixing the particles of Cu-based material with a binder, the exposed surface of the island portion is reduced by the obstacle such as the binder in the base material with the antiviral thin film of the present embodiment. There is nothing.

  In addition, the size of each island is not particularly limited, but if each island is too small, the total exposed area of the island relative to the total volume of the island is too large, and the amount dissolved in water, acid, alkali, etc. There is a risk that the weather resistance and chemical resistance become insufficient. Therefore, each island part preferably has a diameter of 1 nm or more. On the other hand, if each island part is too large, the total exposed area of the island part with respect to the total volume of the island part becomes too small, the number of viruses that can contact the island part decreases, and the antiviral property may not be sufficiently exhibited. . Therefore, it is preferable that each island part has a diameter of 20 nm or less. That is, from both viewpoints, the diameter of the island part is preferably 1 to 20 nm, more preferably 1 to 10 nm, and particularly preferably 2 to 5 nm.

  In addition, as a method for confirming that the island portions are scattered in an island shape, evaluation by a scanning electron microscope (SEM) image, a transmission electron microscope (TEM) image, or the like can be given.

  Next, the base material will be described. Although a base material is not specifically limited, It is preferable to have translucency. As a base material which has translucency, the 1 type, or 2 or more types of raw material chosen from the group which consists of a glass plate, a plastic plate, and a resin film is mentioned. A light-reflective substrate such as a mirror can also be used.

  When the substrate is transparent and translucent, it is preferable to suppress the haze ratio in the visible light region (for example, a wavelength region of 380 to 760 nm) of the substrate with an antiviral thin film to 1.0% or less, More preferably, it is 0.5% or less. Thereby, a favorable design property can be obtained.

  Moreover, the base material may contain the base material main body and the base layer formed so that the base material main body may be contact | connected. When the substrate body is a glass plate, the underlayer preferably has a function of preventing the diffusion of alkali components in the glass plate.

  The underlayer preferably contains at least one selected from the group consisting of silicon oxide, silicon nitride, tin oxide, zinc oxide, zirconium oxide, and a composite oxide of zinc and tin. When tin oxide is included as the underlayer, the tin oxide may be doped with fluorine. A sufficient effect can be obtained if the thickness of the underlayer is in the range of 5 to 10 nm. Prior to the formation of the photocatalyst layer and the island portion, the underlayer can be formed on the substrate body by a known film formation method such as a chemical vapor deposition method, a sputtering method, or a liquid phase method.

  The underlayer may be composed of a plurality of layers. When the underlayer is composed of two layers, for example, a silicon oxide film can be adopted as the first underlayer and a zirconium oxide film can be adopted as the second underlayer from the substrate body side.

  Moreover, when using the glass plate manufactured by the float process as a main-body part (base-material main body) of a base material, the photocatalyst which has a base layer and a titanium oxide as a main component by the thermal CVD method using the heat | fever at the time of glass formation A layer may be formed. The thermal CVD method using heat at the time of forming the float glass is generally called an on-line CVD method (or in-bus CVD method). According to the online CVD method, a CVD apparatus for forming an underlayer and a photocatalyst layer is installed on a glass forming line (for example, in a float bath) by a float method. According to the on-line CVD method, the glass forming by the float method and the formation of the underlayer and the photocatalyst layer by the CVD method can be performed continuously.

  Next, some typical configurations of a substrate with an antiviral thin film are shown in the drawings.

  FIG. 1 is a cross-sectional view showing an example of a typical configuration of a substrate with an antiviral thin film of the present invention. In the base material 1 with an antiviral thin film of this example, an antiviral thin film 21 is formed on the surface of a soda lime glass plate 11 as a base material having translucency. That is, the photocatalyst layer 22 is formed on the surface of the soda lime glass plate 11, and a plurality of island portions 23 (groups of island portions 23) are formed on the surface of the photocatalyst layer 22. The photocatalyst layer 22 has a flat membrane shape. The surface of the island part 23 (specifically, the surface excluding the contact surface with the photocatalyst layer 22 of the island part 23) is exposed, and the surface of the photocatalyst layer 22 is exposed except for the contact surface with the island part 23. ing. As shown in FIG. 1, by depositing the island portion 23 in an island shape, both the antiviral property based on the photocatalytic layer 22 and the antiviral property based on the island portion 23 are ensured, and the material of the glass plate 11 and the photocatalytic layer The color tone and translucency derived from titanium oxide, which is the main component, can be kept good.

  In addition, as shown in FIG. 2, the underlayer 14 is formed on the surface of the soda lime glass plate 11 (base material main body), and the antiviral thin film 21 is formed on the surface of the underlayer 14. The substrate 101 with a conductive thin film may be configured.

  Next, a specific method for manufacturing the island will be described.

  The island can be formed by a sputtering method. The amount of material constituting the islands deposited by sputtering can be highly controlled.

  The sputtering method can be performed in a gas atmosphere containing an inert gas such as argon and oxygen. Moreover, the material which comprises an island part can be deposited in island shape by adjusting the standard film thickness by sputtering method (for example, by setting to 0.1-1.0 nm). Here, the reference film thickness means the film thickness of the continuous film when the total amount of the material constituting the island portion is converted to a continuous film having a uniform film thickness. It does not indicate the actual height itself.

  This reference film thickness can be determined as follows, for example. First, the film forming conditions (film forming apparatus, film forming atmosphere gas, degree of vacuum, substrate temperature, film forming power, etc.) of the island part are determined. Under these film formation conditions, film formation is performed for a relatively long time, and a continuous film made of a material constituting the island portion is formed. Only a film formation time is changed, and film formation is performed several times to obtain a plurality of continuous films having different film thicknesses. The film thickness of the obtained continuous film is measured, and the relationship between the film thickness and the film formation time is determined. The film thickness of the continuous film can be measured by a stylus type step thickness meter or an ellipsometer. From the relationship between the film thickness and the film formation time, a predicted value of the film thickness for a predetermined film formation time can be obtained, and this predicted value can be used as a reference film thickness. That is, a film formation time corresponding to a predetermined reference film thickness is calculated in advance, and the film formation time on the island is set to the calculated film formation time. By such a procedure, it becomes possible to deposit the material which comprises an island part in island shape. In an in-line type sputtering apparatus (apparatus that continuously conveys a base material and passes through a target region (a region where metal bounced off from the target can reach the base material)), the film formation time Corresponds to the time during which each part of the substrate is present in the target area.

When Cu (OH) ₂ is formed using a target composed mainly of metallic copper, an oxidizing agent and a moisture raw material are required to oxidize copper in a metallic state to form a hydroxide. In the present invention, it is preferable to use oxygen contained in the sputtering gas as an oxidant and water existing in the film forming chamber as a moisture source. The moisture in the film formation chamber may be moisture adsorbed on the inner wall of the chamber and the film formation material, but moisture may be positively introduced into the film formation chamber as water vapor.

Furthermore, in the present invention, in order to appropriately adjust the molar ratio A and the supported amount of Cu (OH) ₂ in the island part, the flow rate of oxygen contained in the sputtering gas and the inert gas The flow ratio (oxygen partial pressure) is preferably 5:95 to 22:78, and may be 12:88 to 18:82. The moisture in the film formation chamber is preferably 1 to 3 × 10 ⁻² Pa when expressed by the partial pressure of water in the film formation chamber.

  FIG. 3 shows an example of a sputtering apparatus for forming the island portion. In the sputtering apparatus 50 shown in FIG. 3, the glass plate 31 with the photocatalyst layer in which the photocatalyst layer is formed on the substrate is moved by the transport roller 43. On the other hand, an inert gas (such as argon) and a sputtering gas containing oxygen are supplied from the discharge port 41. Thereafter, the metal Cu bounced off from the target 33 by the collision of the ionized sputtering gas reaches the glass plate 31 with the photocatalyst layer through the opening groove formed by the two parallel shield plates 42. Thereby, the material which comprises an island part accumulates on the glass plate 31 with a photocatalyst layer.

  The film formation rate can be controlled by adjusting the width of the opening groove formed by the shield plate 42. The width of the opening groove can be adjusted within a range of, for example, about 1 to 150 mm. Instead of adjusting the width of the opening groove, or together with this, the film formation rate may be controlled by increasing the conveyance speed of the glass plate 31 with a photocatalyst layer or by keeping the input power low. In addition, when the sputtering conditions are changed, the width of the opening groove may be adjusted in consideration of the film formation guide film thickness and the film formation efficiency.

  The target 33 may contain an appropriate amount of added metal in addition to the metal Cu. As the additive metal, the target 33 includes at least one selected from tin (Sn), iron (Fe), zirconium (Zr), chromium (Cr), zinc (Zn), titanium (Ti), manganese (Mn), and the like. It may be. Thereby, the improvement of the corrosion resistance of an island part can be expected.

  In order to describe the present invention in more detail, examples and comparative examples are shown.

(Example)
(Formation of antiviral thin film)
In all Examples of the present invention, a commercially available photocatalyst cleaning glass plate having a photocatalyst layer formed on a glass plate was used, and an island portion was formed on the surface of the photocatalyst layer by a reactive sputtering method.

  This commercially available photocatalytic cleaning glass plate is manufactured by ACTIV; Pilkington Group Limited. In this photocatalyst cleaning glass plate, a photocatalyst film is formed on a glass plate by a float method, and the photocatalyst layer on the outermost surface of the photocatalyst film is mainly composed of anatase type titanium oxide.

  As described above, the antiviral thin film of the present invention can be obtained even if a photocatalyst film derived from another production method not derived from the CVD method is used. For example, instead of ACTIV, Cleartect S (manufactured by Nippon Sheet Glass Co., Ltd .; including a glass plate and a sputtering method-derived anatase-type titanium oxide film formed on the glass plate) may be used.

  The sputtering apparatus used for the reactive sputtering film formation is an in-line type sputtering apparatus (G-38 type; manufactured by Airco), which is an industrial scale apparatus having a target surface of about 3 m × 30 cm in size. In this apparatus, like a general in-line type sputtering apparatus, a series of vacuum chamber groups are installed so that the atmosphere can be separated by an airtight door between the chambers. A hold chamber is provided as one of the series of vacuum chambers between the film forming chamber for forming a film by sputtering and the outside of the apparatus, and the degree of vacuum of the film forming chamber is set via the hold chamber. In addition, a glass plate in an atmospheric pressure atmosphere can be introduced into the deposition chamber without affecting the sputtering gas atmosphere.

  Specifically, it is as follows. The photocatalyst cleaning glass plate was washed with a neutral detergent and a brush, washed with water, drained with an air knife, introduced into the film formation chamber through a hold chamber, and an island portion was formed by sputtering.

  The target size was 3097 × 280 mm. The distance between the substrate on which the photocatalyst layer was formed and the target was about 100 mm. In order to reduce the film formation rate, as shown in FIG. 3, a shield plate was installed between the base body and the target at a position 50 mm from the base body. As shown in FIG. 3, the shield plate created an elongated gap extending in the direction parallel to the longitudinal direction of the target and perpendicular to the transport direction. The width of the gap was 100 mm. In addition, the base-material main body was not heated at the time of film-forming.

When forming an island part, the conditions which changed the standard sputtering conditions shown below were employ | adopted.
・ Target: Cu
・ Gas pressure: 0.20Pa
Sputtering gas type: oxygen (O ₂ ) 16% + argon (Ar) 84%
-Input power: DC 1,000 W (power density 0.0012 W / cm ² )
・ Conveyance speed: 3,500 mm / min (fine adjustment according to target film formation rate)
・ Reference film thickness: 0.2 nm

  Moreover, as shown in FIG. 3, the discharge port of sputtering gas was installed so that gas might be discharge | released between a shield board and a target.

  The sputtering conditions for the island were determined by separately performing sputtering using a metal Cu as a target, depositing a continuous film of about 20 nm, and analyzing the composition of the continuous film by the In-plane XRD method.

(Evaluation of the existence ratio of Cu-based material in the island)
The abundance ratio of Cu, Cu ₂ O, CuO and Cu (OH) ₂ contained in the island part of the prepared sample was analyzed by XPS method (X-ray photoelectron spectroscopy). The analyzer used is ESCA-5600i manufactured by ULVAC-PHI, and the irradiated X-rays are Al-Kα rays. Spectral waveform separation was performed to determine the abundance ratio (molar ratio) of Cu, Cu ₂ O, CuO, and Cu (OH) ₂ with respect to all Cu atoms. Note that is similar to the spectrum of the spectrum and Cu ₂ O in Cu, for separation of each spectrum it is difficult, for Cu and Cu ₂ O, the sum of the molar ratio and Cu ₂ O molar ratio of Cu Asked.

(Evaluation of the amount of island-based Cu-based material converted to metallic copper)
The total weight in terms of metallic copper of the Cu-based material in the island portion was measured by ICP emission analysis using a calibration curve with a standard solution. The analysis apparatus used is “SPS3520UV” manufactured by SII Nano Technology Co., Ltd. From the measured abundance ratio, total weight, and area of the surface of the photocatalyst layer, Cu, Cu ₂ O, CuO, and Cu (OH) ₂ in terms of metal copper (metal copper equivalent weight per unit area of the photocatalyst layer) The loading was determined as However, for the sample in which the photocatalyst layer was not formed, the metal copper equivalent weight (supported amount) was calculated using the surface area of the glass plate instead of the surface area of the photocatalyst layer.

(Measurement of ratio of average diameter of island and area of island)
Moreover, the average diameter of the island part was measured by TEM observation. Specifically, a TEM photograph was taken using EM-002B manufactured by TOPCON, with an acceleration voltage set to 200 kV and a magnification of 200,000. Similar imaging was performed three times with the visual field at the time of imaging changed, and the size of recognizable particles was measured. Moreover, the area of the island part was calculated from the measured diameter of the island part, and the ratio of the area covered by the island part to the area of the thin film was calculated.

(Antiviral evaluation)
For the antiviral evaluation, Escherichia coli phage Qβ, which is widely used as a test virus in place of influenza virus in the antiviral evaluation, was used. Antiviral properties were evaluated by performing predetermined light irradiation on a phage solution having a predetermined concentration, and measuring the concentration of phage that retains infectivity after light irradiation.

Specifically, it is as follows. 100 μL of the phage solution prepared to a concentration of 4 × 10 ⁹ cells / mL was dropped onto the antiviral thin film of the sample cut into 50 mm square. A commercially available OHP sheet cut into a 40 mm square is placed on top of it to make the thickness of the phage liquid layer uniform on the antiviral thin film, and the area where the phage liquid is in contact with the antiviral thin film is determined to be 40 mm square. It was.

  In order to prevent the phage liquid from volatilizing during the light irradiation, the sample was held in a petri dish kept in a humidity state. That is, a filter paper moistened with pure water was laid on the bottom of the petri dish, a glass piece was placed thereon, a sample was placed thereon, and the petri dish was covered with a quartz glass plate.

The following three treatments were added to the sample held in the petri dish.
-UV irradiation: Using a black lamp (BLB-20S manufactured by Toshiba Lighting & Technology Corporation), UV irradiation with an intensity of 0.25 mW / cm ² was applied for 10 minutes from the outside of the lid of the quartz glass plate.
-Visible light irradiation: Using a normal fluorescent lamp, visible light with an illuminance of 800 Lx is irradiated for 60 minutes from the outside of the lid of the quartz glass plate.
-Dark storage: Do not irradiate light and store petri dishes in a dark room for 180 minutes.

The phage solution after the light irradiation was fully recovered by thoroughly washing the sample and the OHP sheet. This recovered solution was diluted serially at a dilution ratio of 10 ³ to 10 ⁸ times. In this way, a series of test solutions was prepared. The prepared test solution was mixed with a separately prepared E. coli host solution to prepare a series of mixed solutions. This mixed solution was inoculated and cultured in a separately prepared agar medium. Thereafter, the number of plaques produced was visually counted. Based on the number of plaques and the dilution factor, the concentration of phage that retains infectivity after light irradiation in the phage solution was determined as PFU / mL.

  For washing and dilution, phosphate buffered saline containing 0.1 wt% surfactant (Tween 20) based on the total weight was used, and the E. coli host solution contained a large excess of E. coli relative to the phage. Oita.

  For inoculation on the medium, the mixed solution was mixed with the upper layer agar medium and applied to the lower layer agar medium previously fixed to the petri dish. The components of the medium are: upper agar medium is Nutrient Agar 5 g / L, Nutrient Broth 8 g / L, NaCl 0.5 wt%, lower layer agar medium is Nutrient Agar 15 g / L, Nutrient Broth 8 g / L, NaCl 0.5 wt% It is.

  The culture was performed by heating the inoculated petri dish for 15 hours or longer in a constant temperature layer set at 37 ° C.

  All the instruments except the phage solution and the host solution were sterilized with an autoclave sterilizer and a UV sterilizer.

(Measurement of haze ratio)
The haze ratio was measured by using a haze meter (NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.) and making light (wavelength range: 380 to 760 nm) incident from the glass plate side.

Example 1
Except for the following points, sputtering was performed according to the standard sputtering conditions described above. Thereby, the sample of Example 1 was obtained.
Sputtering gas type: oxygen (O ₂ ) 5% + argon (Ar) 95%
・ Partial pressure of water in the film forming chamber: 1.8 × 10 ⁻² Pa

The abundance ratio of the Cu-based material in the island portion and the weight in terms of metal copper were as follows.
Type of Cu-based material Molar ratio Metal copper equivalent weight Total of Cu and Cu ₂ O 0.090 24 ng / cm ²
CuO 0.517 140 ng / cm ²
Cu (OH) ₂ 0.393 107 ng / cm ²

  The diameter of the island part by TEM observation was about 2.8 nm. The ratio of the area covered by the island to the area of the thin film was 0.12.

The evaluation results of antiviral properties were as follows.
Conditions of light irradiation Concentration of phage that maintains infectivity after irradiation UV irradiation 1.0 × 10 ³ PFU / mL or less Visible light irradiation 1.0 × 10 ³ PFU / mL or less Storage in the dark 1.9 × 10 ⁸ PFU / ML

  The haze ratio was 0.2%, haze could not be recognized visually, and it was recognized that the translucency was high.

(Examples 2 to 6)
In Examples 2 to 6, sputtering was performed by changing the following points among the standard sputtering conditions described above. Thereby, the sample of Examples 2-6 was obtained.
Oxygen ratio in sputtering gas Partial pressure of water in film formation chamber Example 2 8% 2.8 × 10 ⁻² Pa
Example 3 12% 2.0 × 10 ⁻² Pa
Example 4 16% 1.8 × 10 ⁻² Pa
Example 5 18% 2.4 × 10 ⁻² Pa
Example 6 22% 2.1 × 10 ⁻² Pa

About the sample of Examples 1-6, the result of having measured the abundance ratio of each Cu type material in an island part, the metal copper conversion weight of each Cu type material in an island part, and antiviral property is shown in Table 1. The notation of nE + m in Table 1 means n × 10 ^{+ m} .

  In any of the samples of Examples 1 to 6, the diameter of the island portion is in the range of 1 to 20 nm, and the ratio of the area covered by the island portion to the area of the thin film is in the range of 0.01 to 0.20. The haze ratio was 1.0% or less.

(Comparative Examples 1 and 2)
In Comparative Examples 1 and 2, the proportion of oxygen in the sputtering gas was changed to 2% and 0%, respectively, and the partial pressure of water in the film forming chamber was changed to 0.94 × 10 ⁻² Pa and 0.56 × 10 ⁻² Pa, respectively. Except for this point, the standard sputtering conditions described above were employed. Thereby, samples of Comparative Examples 1 and 2 were obtained.

(Comparative Example 3)
In Comparative Example 3, sputtering was performed by changing the following points among the sputtering conditions of Example 1. Thereby, a sample of Comparative Example 3 was obtained.
・ Standard film thickness: 5nm
・ Partial pressure of water in the film forming chamber: 1.2 × 10 ⁻² Pa
In Comparative Example 3, the sputtered Cu-based material formed a continuous film rather than an island shape.

(Comparative Example 4)
In Comparative Example 4, a float glass plate without any coating (no photocatalyst layer formed) was used in place of the photocatalyst cleaning glass plate used in the examples. Otherwise, a sample was prepared in the same manner as in Example 1.

  About the sample of Comparative Examples 1-4, the result of having measured the abundance ratio of each Cu type material in an island part, the metal copper conversion weight of each Cu type material in an island part, and antiviral property is shown in Table 1.

(Comparative Example 5)
In Comparative Example 5, no island portion was provided on the photocatalyst cleaning glass plate used in the example. That is, only the photocatalyst cleaning glass plate was used as the sample of Comparative Example 5.

(Comparative Example 6)
In Comparative Example 6, a float glass plate that was not coated at all was prepared. This float glass plate was not provided with any islands. That is, only the float glass plate was used as the sample of Comparative Example 6.

  The evaluation results of the samples of Comparative Examples 5 and 6 are also summarized in Table 1.

(Comparative Example 7)
In Comparative Example 7, a sample in which copper divalent salt-supported rutile titanium dioxide fine particles were fixed on a float glass plate by a sol-gel method using silica as a binder was used. Samples were obtained by the following procedure.

10 parts by weight of rutile titanium dioxide (MT-150A manufactured by Teika Co., Ltd.) is suspended in 100 parts by weight of distilled water, and Cu (NO ₃ ) 2 .3H ₂ O (manufactured by Wako Pure Chemical Industries, Ltd.) It added so that the ratio with respect to a rutile type titanium dioxide of a copper ion might be 0.1 mass%, and it hold | maintained at 90 degreeC for 1 hour, stirring.

  The residue after suction filtration of this suspension was washed with distilled water and further heated and dried at 110 ° C. to obtain rutile-type titanium dioxide fine particles carrying a copper divalent salt.

  The copper divalent salt-supported rutile titanium dioxide 10 parts by weight was added to 100 parts by weight of distilled water, suspended by ultrasonic dispersion, and allowed to stand for 24 hours. By collecting the supernatant from the liquid after standing, a copper divalent salt-supported rutile-type titanium dioxide fine particle dispersion was obtained. According to evaporation to dryness, the dispersion contained 6.1% by mass of copper divalent salt-supported rutile titanium dioxide fine particles.

  Next, 5 parts by mass of tetraethoxysilane (manufactured by Wako Pure Chemical Industries, Ltd.), 0.8 parts by mass of ion exchange water, 0.07 parts by mass of HCl aqueous solution having a concentration of 0.1 mol / L, and ethanol 94 are contained in the reaction vessel. .13 parts by mass was mixed and stirred for 16 hours to obtain a solution of a partially hydrolyzed polycondensation product of tetraethoxysilane.

  By mixing 100 parts by mass of this tetraethoxysilane partially hydrolyzed polycondensate solution and 100 parts by mass of the above-mentioned copper divalent salt-supported rutile type titanium dioxide fine particle dispersion and stirring for 1 hour, the coating material was obtained. Obtained.

  This coating material was applied onto a float glass plate having a thickness of 3.0 mm by spin coating, heated at 100 ° C. for 30 minutes, and dried / cured to obtain a sample in which a coating film was formed on the glass plate. .

  The coating film in the obtained sample was 80 nm. Moreover, the haze rate of this sample was 2.1%, and it was also recognized visually that it was clearly cloudy and had low translucency. Therefore, this sample is unsuitable for applications requiring translucency, design properties, and the like.

(Comparative Example 8)
In Comparative Example 8, in the same coating material as in Comparative Example 7, the mass of titanium oxide included in the coating film is made to correspond to the mass of the titanium oxide film having a thickness of 5 nm.

  The coating material of Comparative Example 7 was diluted 11 times with a solution in which water and ethanol were mixed at a weight ratio of 1: 1, applied onto a glass plate by spin coating, dried at 100 ° C. for 30 minutes and dried. -By curing, a sample in which a 7 nm thick coating film was formed on a float glass plate was obtained.

The haze ratio of this sample was 0.6%, and the abundance ratio of the Cu-based material in the coating film and the weight in terms of metallic copper were as follows.
Type of Cu-based material Molar ratio Metal copper equivalent weight Total of Cu and Cu ₂ O 0.000 0 ng / cm ²
CuO 0.630 345 ng / cm ²
Cu (OH) ₂ 0.370 203 ng / cm ²

Antiviral evaluation was as follows.
Conditions of light irradiation Concentration of phages that maintain infectivity after irradiation UV irradiation 3.2 × 10 ⁷ PFU / mL

(Comparative Example 9)
In Comparative Example 9, a sample obtained by spraying and fixing copper (I) chloride fine powder instead of the island part mainly composed of the Cu-based material of the example was used as a sample. Samples were obtained by the following procedure.

  Photocatalytic cleaning using a suspension of copper (I) chloride (Wako Pure Chemical Industries, Ltd., Wako first grade, 40.9 μm particle size) suspension with water as a suspension medium in the examples. The sample was sprayed on a glass plate with a spray and dried at room temperature to obtain a sample.

  Antiviral properties were evaluated by ultraviolet irradiation, but there was no antiviral properties.

  Various measurement results for the samples of Comparative Examples 1 to 6 and 8 are shown in Table 1.

<Analysis of Examples and Comparative Examples>
As shown in Table 1, in the samples of Examples 1 to 6 where islands are formed on the photocatalyst layer and the molar ratio of Cu (OH) ₂ in the islands exceeds 0.35, ultraviolet light or visible light Irradiation reduced the amount of virus to 1/1000 or less. Moreover, as understood from Table 1, in the samples of Examples 1 to 6, the Cu (OH) ₂ metal copper equivalent (supported amount) was 40 ng / cm ² or more. Moreover, in the sample of Examples 1-5, Cu (OH) ₂ metal copper conversion amount was 70 ng / cm < ² > or more.

In the samples of Comparative Examples 1 to 9, the amount of virus did not decrease as much as in the example. The samples of Comparative Examples 1 to 3 have a low molar ratio of Cu (OH) ₂ in the island part, the sample of Comparative Example 3 has no exposed photocatalyst layer, and the sample of Comparative Example 4 has a photocatalyst layer. This is probably because the sample of Comparative Example 5 does not have an island part, and the sample of Comparative Example 6 does not have a photocatalyst layer or an island part.

The sample of Comparative Example 8 showed little antiviral properties although the molar ratio of Cu (OH) ₂ in the coating film was high. This is considered to be due to the use of rutile type titanium oxide instead of anatase type. It may also be caused by the limited hydrolysis of copper divalent salts that could be brought into contact with the virus due to the partial hydrolysis and condensation polymerization of tetraethoxysilane, and the absence of Cu or Cu ₂ O. .

  The substrate with an antiviral thin film of the present invention can be used for any article that may come into contact with a virus, specifically, architectural window glass, partition glass, door glass, vehicle glass, automotive glass, and display. Glass, mirrors, transparent substrates for DNA analysis, solar cells, portable information devices, hygiene, medical care, electronic equipment, optical components, glass products for biochemical experiments, medical test chips, medical endoscopes and surgical instruments Applicable to optical fiber.

  Use of the substrate with an antiviral thin film according to the present invention can suppress the propagation of viruses in hospitals, nursing homes, houses, etc., and therefore is expected to reduce health and hygiene problems caused by viruses.

Claims (11)

A base material, and an antiviral thin film formed on the base material,
The antiviral thin film has a photocatalyst layer, and an island part mainly composed of a Cu-based material disposed in direct contact with the surface of the photocatalyst layer,
The photocatalyst layer contains anatase type titanium oxide,
The base material with an antiviral thin film whose molar ratio A which is the ratio of the number of moles of Cu (OH) _{2 to} the number of moles of all Cu atoms in the island is greater than 0.35 and less than or equal to 0.80. The molar ratio B, which is the ratio of the total number of moles of CuO and Cu (OH) _{2 to} the number of moles of all Cu atoms in the island, is 0.70 to 0.95. A substrate with an antiviral thin film as described in 1.   The ratio of the sum total of the area of the said island part with respect to the area of the said antiviral thin film when the said antiviral thin film is observed from the said island part is 0.01-0.20. Base material with antiviral thin film.   The diameter with which the average area of the said island part converted into a circle when observed along the thickness direction of the said antiviral thin film is 1-20 nm is with an antiviral thin film of Claim 1 Base material. The substrate is transparent;
The base material with an antiviral thin film of Claim 1 whose haze rate of a wavelength range of 380-760 nm is 1.0% or less. The supported amount of Cu (OH) ₂ calculated by dividing the amount of Cu (OH) ₂ in the island portion converted into metallic copper by the area of the surface of the layer is 4 ng / cm ² or more. 2. A substrate with an antiviral thin film according to 1. The substrate with an antiviral thin film according to claim 6, wherein the supported amount of Cu (OH) ₂ is 40 ng / cm ² or more. The substrate with an antiviral thin film according to claim 7, wherein the supported amount of Cu (OH) ₂ is 70 ng / cm ² or more. A base material, and an antiviral thin film formed on the base material,
The antiviral thin film has a photocatalyst layer, and an island part mainly composed of a Cu-based material disposed in direct contact with the surface of the photocatalyst layer,
The photocatalyst layer contains anatase type titanium oxide,
Wherein the amount of the weight of Cu (OH) ₂ was converted to metallic copper in the island is calculated by dividing the area of the surface of the layer state, and are Cu (OH) supported amount of ₂ 70 ng / cm ² or more,
When the antiviral thin film is observed from above the island portion, the ratio of the total area of the island portion to the area of the antiviral thin film is 0.01 to 0.20. Base material.   The diameter with which the average area of the said island part converted into a circle when observed along the thickness direction of the said antiviral thin film is 1-20 nm is with an antiviral thin film of Claim 9 Base material. The substrate is transparent;
The base material with an antiviral thin film of Claim 9 whose haze rate of a wavelength range of 380-760 nm is 1.0% or less.

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