JP2007229587A - Method for preparing photocatalyst member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prepare a photocatalyst member which keeps photocatalyst particles sticking to a binder resin as firmly as not to be easily peeled off and has an antimicrobial function corresponding to the total quantity of the photocatalyst particles used. <P>SOLUTION: In this preparing method, a volatile solution containing photocatalyst particles in a dispersion state is charged to negative, the binder resin 4 is applied on a member surface, the member is charged to positive, the volatile solution containing the photocatalyst particles 6 charged to negative in the dispersion state is ejected toward the surface of the binder resin 4 on the condition that the photocatalyst particles 6 charged to negative in the volatile solution containing the photocatalyst particles 6 charged to negative in the dispersion state should reach the surface of the binder resin 4 before hardening of the surface of the binder resin 4 with the evaporation of volatile components in the volatile solution containing the photocatalyst particles 6 charged to negative in the dispersion state in the step, and the photocatalyst particles are dried in the state of contact with the binder resin 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a photocatalytic member having an antibacterial action.

  As semiconductor particles such as titanium dioxide, those having a photocatalytic action that radicalizes oxygen in the atmosphere using light such as sunlight (collectively referred to as photocatalytic particles) are known. Since oxygen radicals generated by the photocatalytic action decompose organic substances such as microorganisms, antibacterial action due to oxygen radicals is recognized in a member (photocatalytic member) on which a resin layer containing photocatalyst particles is formed. Such a photocatalytic member is used, for example, as a wall material, floor material, or ceiling material in a hospital treatment room where a sanitary environment is required.

As a method for producing the photocatalyst member, a method described in Patent Document 1 is known. According to this, a paint (solution) obtained by dispersing photocatalyst particles in a binder resin as a main raw material is applied to an object (member) by electrostatic coating. And a baking process is given and the photocatalyst member which has the layer of resin containing a photocatalyst particle on the surface is manufactured. By using electrostatic coating with good throwing power and little paint loss, a resin layer is efficiently formed on the surface of the member. And a part of photocatalyst particle will be in the state exposed to air | atmosphere from the layer of resin.
JP-A-8-302498

  However, in order for the photocatalyst particles to exert photocatalytic action, it is necessary to come into contact with oxygen in the atmosphere. Therefore, the resin layer formed by the production method described above is partially photocatalyst exposed from the outer surface of the resin layer. The particles alone generate oxygen radicals, and the remaining photocatalytic particles do nothing. Therefore, an antibacterial action according to the total amount of photocatalyst particles introduced at the time of manufacture could not be obtained.

Therefore, the amount of the photocatalyst particles is relatively increased and only the necessary minimum amount of binder resin is added. By doing so, the proportion of the photocatalyst particles exposed from the resin layer can be increased. However, the sticking of the photocatalyst particles is weakened in proportion to the decrease in the binder resin content ratio with respect to the photocatalyst particles, and the photocatalyst particles are easily peeled off from the photocatalyst member. For example, as shown in FIG. 6A, the applied photocatalyst particles 30 are in contact with the member 50 while being covered with the binder resin 40. When baking is performed in this state, the photocatalyst particles 30 are fixed to the member 50 only with a part of the cured binder resin 40a at the contact portion between them (FIG. 6B). Originally, the photocatalyst particles 30 are peeled off from the member 50 as soon as a physical stimulus such as rubbing with a cloth is applied because they are fixed with only a part of the cured binder resin 40a (FIG. 6C). When the member 50 is used as a wall material in a hospital treatment room, the surface of the wall material in the treatment room is frequently sterilized and washed with an alcohol solution, so that part of the cured binder resin 40a that fixes the photocatalyst particles 30 is dissolved in the alcohol solution. put out. For this reason, peeling of the photocatalyst particles 30 becomes more severe.
For this reason, a photocatalyst member having an antibacterial action corresponding to the total amount of the photocatalyst particles used has been eagerly desired while being fixed so that the photocatalyst particles do not peel off.

  In view of the above problems, the present invention manufactures a photocatalyst member having antibacterial action according to the total amount of photocatalyst particles fixed to a binder resin so as not to easily peel off.

  In the method for producing a photocatalyst member of the first invention, a volatile solution containing the photocatalyst particles in a dispersed state is negatively charged and the member is positively charged. Then, a binder resin is applied to the surface of the member, and a volatile solution containing negatively charged photocatalyst particles in a dispersed state is sprayed toward the binder resin surface while the binder resin surface is uncured. At this time, the volatile solution containing the negatively charged photocatalyst particles in a dispersed state until the negatively charged photocatalyst particles in the volatile solution containing the negatively charged photocatalyst particles in a dispersed state reaches the surface of the binder resin. It sprays on the conditions which the volatile component in an ionic solution emits in the middle of injection.

  As the above-mentioned conditions, for example, a volatile solution containing photocatalyst particles in a dispersed state is sprayed and brought into a floating state as long as an electrical attractive force is received from a positively charged member. While floating in the air in the floating state, volatile components in the volatile solution containing the photocatalyst particles in a dispersed state are emitted, and the photocatalyst particles that maintain the dispersed state in the solution are electrically directed toward the binder resin surface. Gravitate.

  Furthermore, it is desirable that the volatile solution containing the photocatalyst particles in a dispersed state is in the vicinity of the binder resin surface. For example, a volatile solution containing the photocatalyst particles in a dispersed state is diffused and sprayed toward the binder resin surface, and then is brought into a floating state.

  The photocatalyst particles that have reached the surface of the binder resin are brought into contact with the uncured binder resin by electrical attraction, and are localized on the surface of the binder resin with the photocatalyst particles being exposed from the film. Then, due to the interfacial tension acting between the photocatalyst particles and the binder resin, the liquid surface of the binder resin in the vicinity of the contact point with the photocatalyst particles rises and comes into contact with the photocatalyst particles, thereby reducing the gap between the two.

Then, the binder resin is tightened by drying the binder resin. The photocatalyst particles follow the tightening and sink into the binder resin. For this reason, the photocatalyst particles are appropriately embedded and fixed in the binder resin and are not easily peeled off.
For this reason, the photocatalyst particles are fixed to the binder resin so as not to easily peel off, and the photocatalyst particles are localized in an exposed state on the surface of the binder resin layer. That is, a photocatalyst member having an antibacterial action (photocatalytic function) corresponding to the total amount of photocatalyst particles contained in the binder resin layer is produced.

  As the photocatalyst particles, semiconductor particles having a photocatalytic action that radicalizes oxygen using light such as sunlight can be used. In particular, titanium dioxide carrying a metal has a photocatalytic action due to positive ions generated from the metal. This is preferable because the photocatalytic action is strong.

In addition, alcoholic solvents such as methanol, ethanol, and isopropyl alcohol can be used as volatile components, and ether-based solvents and ketone-based solvents such as acetone can be used as long as they can be emitted in the atmosphere. it can. From the viewpoint of safety, it is desirable to use ethanol or denatured ethanol as a volatile component.
Two or more kinds of the above volatile components may be mixed and used. Further, water may be mixed as a dispersant as long as it does not have a significant adverse effect on the fixation of the photocatalyst particles.

Further, as the binder resin, a solution in which a thermosetting resin that is cured by applying heat is dissolved in a solvent can be used. In particular, it is desirable in terms of manufacturing cost to use a solution of a thermosetting acrylic resin that is used as a coating component. Further, even a solution of a thermoplastic resin that maintains a cured state at room temperature can be used.
In addition, what melt | dissolved thermosetting resin or thermoplastic resin itself can also be used as binder resin.

  In the method for producing a photocatalyst member of the second invention, in the first invention, a volatile solution containing negatively charged photocatalyst particles in a dispersed state is sprayed in a heated state. By heating a volatile solution containing negatively charged catalyst particles in a dispersed state, the viscosity of the solution is lowered, and a volatile solution containing dispersed negatively charged catalyst particles in a dispersed state is miniaturized. By doing so, volatile components are easily emitted into the atmosphere.

In the method for producing a photocatalyst member of the third invention, in the first invention or the second invention, the photocatalyst particles are anatase titanium dioxide carrying silver.
In anatase-type titanium dioxide carrying silver, positive ions generated from silver assist the photocatalytic action. For this reason, a photocatalytic member having a high photocatalytic action can be produced even in a place with a relatively small amount of light such as indoors.

  According to the first invention, it is possible to manufacture a photocatalyst member having antibacterial action according to the total amount of photocatalyst particles contained in the binder resin layer by fixing the photocatalyst particles to the binder resin so that they do not easily peel off. Further, according to the second invention, volatile components are easily emitted into the atmosphere. Furthermore, according to the third invention, a photocatalytic member having a high photocatalytic action can be produced.

The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 shows the positional relationship between the electrostatic coating machine 12 of this embodiment and the member 2 to which photocatalysis is to be imparted.
The manufacturing method of the photocatalyst member in a present Example consists of a dispersion | distribution process, an electrostatic process, and a drying process, and is demonstrated in order below.

[Dispersion process]
Anatase-type titanium dioxide (an example of photocatalyst particles, hereinafter referred to as silver-carrying titanium dioxide) formed by supporting silver in ethanol (an example of a volatile component) is put into a sealable stirring vessel 13.
At this time, 0.1 to 3.0 parts by weight of silver-supported titanium dioxide is added to 100 parts by weight of ethanol. When the amount of the silver-supported titanium dioxide to be added is less than 0.1 parts by weight, the antibacterial action itself derived from the silver-supported titanium dioxide is reduced, and a photocatalytic member that exhibits a practical antibacterial action cannot be obtained. Further, it is assumed that more silver-supported titanium dioxide is added than 3.0 parts by weight with respect to 100 parts by weight of ethanol. In this case, the polarity of charge dispersion is lost, the dispersibility is lost, and the silver-supported titanium dioxide aggregates and settles. In other words, the intermolecular force generated between the silver-carrying titanium dioxides is superior to the electrical influence received from ethanol, and the silver-carrying titanium dioxides are attracted to each other by the intermolecular force and aggregate to form a large lump. In order to obtain a practical antibacterial action while ensuring appropriate dispersibility, 0.2 to 0.6 parts by weight of silver-supported titanium dioxide is added to 100 parts by weight of ethanol.

  Further, 5 to 15 parts by weight of water may be added to 100 parts by weight of ethanol. Water molecules coordinate to silver-supported titanium dioxide in ethanol, and silver-supported titanium dioxide is stably dispersed in ethanol. If 15 parts by weight or less of water is added with respect to 100 parts by weight of ethanol, almost all of the water will diverge in the floating state described later, so that there is no significant adverse effect on the fixation of the silver-supported titanium dioxide. When the amount of water to be added is more than 15 parts by weight, all the water does not diverge in a floating state to be described later, and the ratio of silver-carrying titanium dioxide that reaches the surface of the binder resin while being covered with water increases. The silver-carrying titanium dioxide covered with water loses its adhesiveness and peels from the binder resin layer over time. The part where the silver-supported titanium dioxide is peeled becomes like an avatar, and the appearance of the photocatalyst member is deteriorated. In order to reliably exhibit the adhesiveness of the silver-supported titanium dioxide while stably dispersing the silver-supported titanium dioxide in ethanol, 8 to 12 parts by weight of water is added to 100 parts by weight of ethanol.

  Then, the stirring vessel 13 is sealed, and stirred with a propeller equipped stirrer 14 so that the silver-supported titanium dioxide in the stirring vessel 13 is uniformly dispersed in ethanol. In this way, an ethanol solution containing silver-supported titanium dioxide in a dispersed state (an example of a volatile solution, hereinafter simply referred to as an ethanol solution) is prepared. In addition, although it may move to the following electrostatic process immediately after preparation, since the condensation of silver carrying | support titanium dioxide is suppressed during stirring with the stirrer 14, ethanol solution is stored in the sealed stirring container 13. May be.

[Electrostatic process]
Next, the ethanol solution is sent to the heating cylinder 10 through the first tube 11 and heated.
The heating temperature is preferably 15 ° C. or higher, and more preferably 30 ° C. or higher. If the heating temperature is less than 15 ° C., the effect of promoting the diffusion of volatile components cannot be expected. The upper limit of the heating temperature can be set according to the boiling point of the volatile component to be used, and is preferably set to 60 ° C. or less in consideration of safety. The temperature for obtaining the effect of promoting the emission of volatile components while considering safety is 30 ° C to 50 ° C.

The heated ethanol solution is sent to the electrostatic gun 8 through the second tube 9. The electrostatic gun 8 communicates with a negative electrode (cathode) of a high voltage generator (not shown). The member 2 disposed at a position facing the electrostatic gun 8 is grounded in advance. For this reason, the member 2 becomes a positive electrode by disposing the electrostatic gun 8 leading to the negative electrode at an appropriate position. In this way, an electrostatic field (a range that receives an electric attractive force) is formed between the electrostatic gun 8 and the member 2. The working voltage is, for example, 25 kV to 60 kV.
By diffusing and spraying the ethanol solution with the electrostatic gun 8, the silver-supported titanium dioxide in the ethanol solution is negatively charged. Hereinafter, the negatively charged silver-carrying titanium dioxide is denoted by the symbol 6.

In parallel with the above-mentioned operation, a thermosetting acrylic resin was dissolved in an appropriate solvent to prepare a solution 4 containing a thermosetting acrylic resin (an example of a binder resin, hereinafter referred to as a thermoplastic acrylic resin solution 4). After that, it is applied to the surface of the member 2 facing the electrostatic gun 8. The ethanol solution is sprayed from the electrostatic gun 8 toward the surface of the thermosetting acrylic resin solution 4 while the surface of the applied thermosetting acrylic resin solution 4 is uncured.
The nozzle diameter of the electrostatic gun 8 is, for example, φ0.8 to 1.6 mm.

  The uncured state of the surface of the thermosetting acrylic resin solution 4 means that the liquid surface of the thermosetting acrylic resin solution 4 in contact with the negatively charged silver-carrying titanium dioxide 6 swells as a result of interfacial tension, as will be described later. This refers to the state of maintaining sex. For example, in terms of human touch, it means a state in which the resin solution 4 adheres to the finger belly when the thermosetting acrylic resin solution 4 is lightly touched with the finger belly.

At this time, the ethanol in the ethanol solution diverges in the middle, and only the negatively charged silver-carrying titanium dioxide 6 is diffused and jetted on the condition that it reaches the surface of the thermosetting acrylic resin solution 4. For example, when the electrostatic gun 8 and the member 2 are arranged at a distance of 500 mm, the ethanol solution can be used in a range of discharge pressure of 0.5 to 1.5 kg / cm ² and air pressure of 1.5 to 3.0 kg / cm ^2. Spray.
The mist-like ethanol solution sprayed under the above conditions loses its straight running force in the middle of reaching the surface of the thermosetting acrylic resin solution 4 and becomes a floating state in the vicinity of the thermosetting acrylic resin solution 4. For example, referring to FIG. 1, the range in which the alcohol solution has a straight force (the range in which the alcohol solution diffuses) is S1, and the range in which the alcohol solution floats is S2. The ethanol in the ethanol solution diverges while floating in the air in a floating state, and the negatively charged silver-carrying titanium dioxide 6 that maintains the dispersed state in the ethanol solution is electrically directed toward the thermosetting acrylic resin solution 4 surface. Be drawn to.

FIG. 2 is an explanatory diagram for explaining the behavior of the photocatalyst particles in the electrostatic process and the subsequent drying process. FIGS. 4A and 4B show the negatively charged silver-carrying titanium dioxide 6 during the electrostatic process.
The negatively-charged silver-carrying titanium dioxide 6 that has reached the surface of the thermosetting acrylic resin solution 4 comes into contact with the uncured thermosetting acrylic resin solution 4 only by an electric attractive force (see FIG. 2A). Since the negatively charged silver-carrying titanium dioxide 6 does not have a linear force enough to enter the thermosetting acrylic resin solution 4, the negatively charged silver-carrying titanium dioxide 6 is in contact with the surface of the thermosetting acrylic resin solution 4. In this state, the movement is stopped, so that the negatively charged silver-carrying titanium dioxide 6 is localized in the exposed state. At this time, the thermosetting acrylic resin solution 4 in the vicinity of the contact point with the negatively charged silver-carrying titanium dioxide 6 due to the interfacial tension between the negatively-charged silver-carrying titanium dioxide 6 and the thermosetting acrylic resin solution 4. As the liquid level rises, it comes into contact with the negatively charged silver-carrying titanium dioxide 6. This reduces the gap between them (see FIG. 2B).

If the negatively charged silver-carrying titanium dioxide 6 is covered with ethanol, the silver-carrying titanium dioxide 6 and the thermosetting acrylic resin solution 4 are not in direct contact with each other, so that the effect of the interfacial tension cannot be obtained. Moreover, the thermosetting acrylic resin solution 4 hardly dissolves in ethanol. Therefore, ethanol inhibits the fixation of the silver-supported titanium dioxide 6. For this reason, it is necessary to spray the ethanol in the ethanol solution under the condition that the silver-carrying titanium dioxide 6 that has diverged on the way and reaches the surface of the thermosetting acrylic resin solution 4.
However, it is not necessary to completely remove ethanol from the silver-supported titanium dioxide 6, and some ethanol may remain as long as the above-described interfacial tension works.

[Drying process]
Next, the thermosetting acrylic resin solution 4 is dried. The drying method may be natural drying in which the member 2 is left in the atmosphere, or forced drying in which the member 2 is dried with a heating device (not shown). For example, when performing a baking process, the member 2 after the electrostatic process is put into a baking furnace (not shown) and heated. The heating temperature and the heating time can be appropriately changed depending on the binder resin to be used. For example, in the case of the thermosetting acrylic resin 4, heating is performed at 150 to 160 ° C. for 30 to 40 minutes. In the case of a thermosetting melamine resin, it is heated at 110 to 130 ° C. for 20 to 45 minutes.

The member 2 is dried under the above-described conditions, and the thermosetting acrylic resin in the thermosetting acrylic resin solution 4 is cured and tightened. Silver-carrying titanium dioxide (which is not negatively charged and therefore given the sign of 7 for convenience) sinks into the thermosetting acrylic resin solution 4 following this tightening. Therefore, the silver-carrying titanium dioxide 7 is appropriately embedded and fixed in the thermosetting acrylic resin layer 5 formed by drying the thermosetting acrylic resin solution 4 and is not easily peeled off.
FIG. 2C shows the appearance of the silver-supported titanium dioxide 7 after the drying step.

FIG. 3 is a cross-sectional view of the photocatalytic member 20 showing the arrangement of the silver-carrying titanium dioxide 7.
In this way, the silver-carrying titanium dioxide 7 is fixed to the thermosetting acrylic resin layer 5 so as not to easily peel off. The fixed silver-carrying titanium dioxide 7 is localized in the exposed state on the surface of the thermosetting acrylic resin layer 5 as described above. Therefore, the photocatalytic member 20 having an antibacterial action according to the total amount of the silver-carrying titanium dioxide 7 included in the thermosetting acrylic resin layer 5 can be manufactured.

Hereinafter, the present invention will be described based on test examples. The present invention is not limited to this test example.
[Test Example 1]
(Preparation of Examples 1-3)
(1) Preparation of ethanol solution (volatile solution) 5.0 parts by weight of silver-supported titanium dioxide was added to 100 parts by weight of water to prepare a silver-supported titanium dioxide dispersed aqueous solution. 10 parts by weight of a silver-supported titanium dioxide dispersion aqueous solution was added to 90 parts by weight of an ethanol solvent to prepare an ethanol solution. And the ethanol solution was prepared by stirring for 10 minutes with the stirrer with a propeller.
(2) Preparation of thermosetting acrylic resin solution (binder resin) Thermosetting acrylic resin (Acroze # 6000 manufactured by Dainippon Paint Co., Ltd. in this test example) was used as a solvent (Dainippon Paint Co., Ltd. manufactured in this test example). It was dissolved in Acrose # 6000 thinner) to obtain a thermosetting acrylic resin solution (non-volatile content: 50 to 60%). This thermosetting acrylic resin solution was applied to the surface of an aluminum plate (50 mm × 50 mm, plate thickness 1.5 mm) to produce a binder resin piece in which an uncured layer of a binder resin solution having a thickness of 10 μm was formed.
(3) Electrostatic coating and baking treatment The electrostatic coating was performed indoors (temperature 10 ° C. and humidity 40 ° C.) (see FIG. 1).
The binder resin piece was placed 500 mm away from the electrostatic gun. The ethanol solution was heated to 20 ° C. with a heating cylinder. Then, an ethanol solution was sprayed for 8 seconds from the electrostatic gun (operating voltage 30 kV, nozzle diameter φ 1.1 mm) toward the surface of the binder resin solution of the binder resin piece (spraying condition: discharge pressure 0.8 kg / cm ² , air pressure 2 .5 Kg / cm ² ). Then, the binder test piece was put into the heating apparatus, the baking process was performed for 30 minutes at 150 degreeC, and each test piece was prepared.

  Under the above-described conditions, a test piece of Example 1 was obtained by baking a binder resin piece (applying a thermosetting acrylic resin solution on an aluminum plate) and spraying an ethanol solution 5 minutes later. A test piece of Example 2 was obtained by spraying an ethanol solution 10 minutes after producing the binder resin piece and then firing. A test piece of Example 3 was obtained by spraying an ethanol solution 15 minutes after producing the binder resin piece and then firing.

(Preparation of Comparative Examples 1 and 2)
As Comparative Example 1, a thermosetting acrylic resin and silver supported titanium dioxide were added to ethyl acetate to prepare a comparative solution. The mixing ratio of the above components was thermosetting acrylic resin: silver-supported titanium dioxide dispersed aqueous solution: thinner solvent = 1: 6: 3. That is, only the minimum necessary thermosetting acrylic resin was added to the silver-supported titanium dioxide. This comparative solution was applied to the surface of an aluminum plate (50 mm × 50 mm, plate thickness 1.5 mm) to produce a binder resin piece in which a comparative binder resin layer having a thickness of 10 μm was formed. A test piece of Comparative Example 1 was obtained by baking this binder resin piece under the same conditions as in the above example.
Moreover, as Comparative Example 2, an antibacterial performance test was performed on the aluminum plate (in a state where no binder resin layer was formed).

(Antimicrobial performance test)
The antibacterial performance test by the film adhesion method (JIS Z 2801) was performed on each test piece of the example and the comparative example. The bacteria used for the antibacterial performance test was Escherichia coli (initial number of bacteria 2.1 × 10 ⁵ ). An antibacterial performance test (first antibacterial performance test) was performed on each test piece after the firing treatment. Furthermore, each test piece after the baking treatment was wiped 365 times with a cloth soaked with 99% alcohol and then subjected to an antibacterial performance test (second antibacterial performance test).

Table 1 is a table showing the results (the number of bacteria) of the antibacterial performance tests of Examples 1 to 3 and Comparative Examples 1 and 2.
From Table 1, Examples 1-3 and Comparative Example 1 exhibited the same antibacterial action in the first antibacterial performance test. That is, it turned out that Examples 1-3 exhibit the same favorable antibacterial action as the comparative example 1 which contains a large amount of silver carrying | support titanium dioxide.
Moreover, Examples 1-3 demonstrated the favorable antimicrobial effect also in the 2nd antimicrobial performance test. That is, in Examples 1 to 3, practical antibacterial action was recognized even when each test piece was wiped 365 times with a cloth soaked with 99% alcohol. On the other hand, in Comparative Example 1, a sharp decrease in antibacterial action was observed. Thereby, in Examples 1-3, compared with the comparative example 1, it turned out that silver carrying | support titanium dioxide adheres more firmly with respect to a thermosetting acrylic resin layer, and does not peel easily.

[Test Example 2]
(Preparation of Examples 4-11)
As a volatile solution, an ethanol solution prepared under the same components and the same conditions as those in Examples 1 to 3 was used.
As the binder resin, an acrylic resin clear (non-volatile content 45 to 45) obtained by dissolving a thermosetting acrylic resin (in this test example, Akrose # 6000 manufactured by Dainippon Paint Co., Ltd.) in a solvent (acrose # 6000 thinner manufactured by Dainippon Paint Co., Ltd.). 50%) was used. The acrylic resin clear does not contain titanium dioxide (pigment component) in its components. This acrylic resin clear was applied to the surface of a glass plate (50 mm × 50 mm, plate thickness 1.5 mm) to produce a binder resin piece in which an uncured layer of acrylic resin clear having a thickness of 10 μm was formed. The electrostatic coating and baking treatment were performed under the same conditions as shown in [Test Example 1].

Under the above conditions, a test piece of Example 4 was prepared by spraying an ethanol solution 5 minutes after producing a binder resin piece (applying acrylic resin clear on a glass plate) and then firing. In the following order, the sample that was fired after spraying after 10 minutes was fired after the test piece of Example 5, the test piece that was fired after spraying after 15 minutes was the test piece of Example 6, and the sample fired after being sprayed after 20 minutes was Example 7. Example 8 after spraying after 30 minutes, fired after spraying after 40 minutes, Example 9 after spraying after 40 minutes, Example 10 after spraying after spraying after 50 minutes, and after spraying after 60 minutes The fired product was used as a test piece of Example 11.
Further, as Comparative Example 3, an antibacterial performance test was performed on the glass plate (in a state where no binder resin layer was formed).

(Antimicrobial performance test)
The antibacterial performance test was performed under the same conditions as in [Test Example 1], and the bacteria used in the antibacterial performance test was Staphylococcus aureus (Staphylococcus aureus NBRC 12732 initial bacterial count 60,000). Each test piece after the baking treatment was wiped 365 times with a cloth soaked with 99% alcohol and then subjected to an antibacterial performance test (second antibacterial performance test).

(Section imaging and X-ray analysis using a scanning electron microscope)
The test piece of Example 5 (sprayed after 10 minutes) was taken with a scanning electron microscope after the binder resin layer was cut vertically (see FIG. 4).
Further, a sample obtained by thinly cutting the surface layer of the binder resin layer of the test piece of Example 5 was subjected to X-ray analysis (see FIG. 5).

Table 2 is a table showing the results (bacterial count) of the antibacterial performance tests of Examples 4 to 11 and Comparative Example 3.
From Table 2, it was found that the uncured state of the acrylic resin clear continued until 5 to 60 minutes after showing good antibacterial action in any of Examples 4 to 11. Further, it was found that when the ethanol solution was sprayed 40 minutes before the acrylic resin clear was applied, the silver-supported titanium dioxide strongly adhered to the surface of the binder resin.
Furthermore, it was found that even S. aureus (about 1 μm) smaller than E. coli (about 5 μm) exerts an antibacterial action. In other words, in this test, it was found that the gap between the silver-carrying titanium dioxides adhered to the surface of the photocatalyst member was so small that even small microorganisms of about 1 μm could be sterilized, and the silver-carrying titanium dioxides adhered in a dense state .

FIG. 4 is a view showing a cross section of the binder resin layer (Example 5) by a scanning electron microscope.
Cross-sectional photography with a scanning electron microscope revealed that silver-carrying titanium dioxide was fixed on the surface of the binder resin.
FIG. 5 is a diagram showing X-ray analysis data of the surface component of the binder resin layer.
X-ray analysis revealed that titanium (Ti) was contained in the surface layer of the binder resin layer. The acrylic resin clear used in this test does not contain titanium (Ti). That is, it was proved from the X-ray analysis data that the substance fixed on the surface of the binder resin was silver-supported titanium dioxide.

The manufacturing method of the photocatalyst member of the present invention is not limited to the appearance, configuration, processing, display example, and the like described in the present embodiment, and various changes, additions, and deletions are possible.
In this embodiment, an example in which a thermosetting acrylic resin solution is used as a binder resin has been described. In addition, solvents such as silicon resin, alkyd resin, aminoalkyd resin, vinyl resin, epoxy resin, polyester resin, and urethane resin are used. System paints and UV curable resins can be used.
Solvents that dissolve the resin include aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, alcohols, ketones, esters, and ethers that can dissolve the binder resin used. A solvent used as a solvent can be used, and two or more of these solvents may be mixed and used. Furthermore, coloring components such as pigments may be added to these solvents.

For example, a natural drying (room temperature drying) type coating solution such as a phthalic acid resin, an acrylic resin, or a reaction-curing acrylic urethane resin may be used as the binder resin.
Similarly, an aqueous acrylic emulsion resin solution can also be used as the binder resin. The acrylic emulsion resin solution is suitable for natural drying because the volatile components in the solution diverge and the acrylic resins are fused to form a binder resin layer.

Further, as the binder resin, a polymerizable liquid resin that forms a poorly soluble binder resin layer by causing a polymerization reaction between binder resins such as liquid polyethylene resin, unsaturated polyester resin, and polyurethane resin (by sol-gel change) can be used. These polymerizable liquid resins do not need to be dissolved in a solvent. And since a hardening binder resin layer is formed by a polymerization reaction, it is suitable for natural drying.
Furthermore, a two-component room temperature curing paint such as a polyester resin that causes a condensation reaction by adding a crosslinking agent can be used, and these binder resins are also suitable for natural drying.

  Further, a molten resin can be used as the binder resin. For example, an ethanol solution is sprayed in advance on the inner surface of the cavity of the injection mold. Pour molten resin into it. After the resin is cured, silver-carrying titanium dioxide adheres to the surface.

It is a related figure which shows the positional relationship of an electrostatic coating machine and a member. It is explanatory drawing for demonstrating the behavior of the photocatalyst particle in an electrostatic process and a drying process. It is sectional drawing of the photocatalyst member which shows the arrangement | positioning state of a photocatalyst particle. It is a figure which shows the cross section of the binder resin layer by a scanning electron microscope. It is a figure which shows the X-ray-analysis data of a binder resin layer surface layer component. It is explanatory drawing for demonstrating the behavior of the photocatalyst particle in a conventional manufacturing method.

Explanation of symbols

2 Member 4 Thermosetting acrylic resin solution 5 Thermosetting acrylic resin layer 6 Negatively charged silver-carrying titanium dioxide 7 Exposed silver-carrying titanium dioxide 8 Electrostatic gun 9 Second tube 10 Heating cylinder 11 First tube 12 Electrostatic coating machine 13 Stirrer 14 Stirrer 20 Photocatalyst member

Claims (3)

In the method for producing a photocatalyst member for producing a photocatalyst member having a photocatalytic function by fixing photocatalyst particles to the member,
A volatile solution containing the photocatalyst particles in a dispersed state is negatively charged,
A binder resin is applied to the surface of the member, and the member is positively charged;
When injecting a volatile solution containing the negatively charged photocatalyst particles in a dispersed state toward the binder resin surface while the binder resin surface is in an uncured state,
Volatile components in the volatile solution containing the negatively charged photocatalyst particles in a dispersed state are emitted in the middle, and the negatively charged photocatalyst in the volatile solution containing the negatively charged photocatalyst particles in a dispersed state Injecting under the condition that particles reach the binder resin surface,
The method for producing a photocatalyst member, wherein the photocatalyst particles are dried in contact with the binder resin.   The method for producing a photocatalyst member according to claim 1, wherein a volatile solution containing the negatively charged photocatalyst particles in a dispersed state is sprayed in a heated state. In the manufacturing method of the photocatalyst member according to claim 1 or 2,
The method for producing a photocatalyst member, wherein the photocatalyst particles are anatase-type titanium dioxide carrying silver.