JPH10328611A - Production of removal member for harmful substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a member for removing harmful substance in which covering is efficiently performed without using a solvent and also performance for removing harmful substance and durability are excellent. SOLUTION: In the method for producing a removal member of harmful substance, the mixture of metallic powder or polymer powder coating and photocatalytic substance is conveyed by gas flow and also heated and melted. A covering layer is formed by spraying the produced molten mixture on the surface of a supporting member. Further, in the case of forming the covering layer, a first layer consisting of the covering layer of metallic powder or polymer powder coating is formed on the supporting member and thereafter a second layer consisting of the covering layer of the mixture of metallic powder or polymer powder coating and the photocatalytic substance is formed on the first layer. Titanium dioxide of 10-300 m<2> /g specific surface area is used for the photocatalytic substance. Furthermore, thickness of the covering layer consisting of the mixture of metallic powder or polymer powder coating and the photocatalytic substance is 0.2-5 mm. Polymer powder coating is transparent polymer powder coating and inorganic powder of 1-20 μm average particle diameter may be added to the above-mentioned mixture as transparent substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a harmful substance removing member, and more particularly to a method for producing a harmful substance removing member which has improved purification performance, prevents deterioration of materials, and is durable. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Recently, as destruction of the global environment has been regarded as a problem, attention has been paid to the fact that photocatalysts are useful for preventing or purifying the global environment. It has been found that this photocatalyst exhibits the action of decomposing and purifying organic substances when exposed to radiation such as ultraviolet rays.
O _X of purification, purification of water, antibacterial and antifungal, is the development of products that are applied to a deodorized, etc. were carried out. Specifically, Japanese Patent Application Laid-Open No. 2-273
No. 514 discloses a harmful substance remover obtained by kneading a titanium dioxide semiconductor and clay and drying the mixture. JP-A-6-327965 discloses that a semiconductor (for example, titanium dioxide or the like) having a band gap of 0.5 to 5 eV is dispersed in a hydrated aggregate of a hydraulic compound as a remover of harmful substances such as ethylene. And JP-A-7-171408 discloses a photocatalyst in which photocatalyst particles are adhered to a substrate via a hardly decomposable binder. Has a layer made of a mixture of a photocatalyst and a hardly decomposable binder on the surface of the base, or a first layer containing no photocatalyst is provided on the base, and further, a hardly decomposable binder is formed on the first layer. The structure in which a second layer composed of the adhesive and the photocatalyst particles is provided is shown.

Further, as for a binder using a fluororesin as a binder, Japanese Patent Application Laid-Open No. Hei 4-284851 discloses that a mixture of a fluororesin and titanium dioxide is applied to a porous nickel substrate with an iron and then pressed. Thereafter, a method of performing heat treatment at 150 ° C. is described.

[0004]

However, as described above, the photocatalyst described in Japanese Patent Application Laid-Open No. 7-171408 uses a usual roller coating method, dipping method, spraying method, or the like as a method for supporting the photocatalyst on a substrate. And Japanese Patent Laid-Open No. 4-2
No. 84851, a mixture of a fluororesin and titanium dioxide is applied with a trowel and then pressed.
Heat treatment, but the usual roller coating method like the former,
In the immersion method or the spraying method, when a fluororesin is used as a binder, a solvent must be used, which is not preferable in terms of work, and the harmful substance removal performance (for example, NOx purification performance, etc.) is impaired. There is also a problem with gender. In the latter method of coating, pressing and heat-treating, the process is complicated and the economic efficiency is low, and the performance of removing harmful substances and the durability are not satisfactory. Further, in these coating methods, coating of the metal powder is substantially impossible, and there is a problem in obtaining a coating layer having a sufficient thickness even in the case of a fluororesin.

[0005] The inventors of the present invention have conducted various studies on the above-mentioned problems, and found that the durability due to decomposition / deterioration due to titanium dioxide was determined by using a metal powder or a fluororesin as a binder for titanium dioxide, and using a thermal spraying technique. A method for producing a harmful substance removing member that has improved harmful substance removing performance (for example, NOx purification performance, etc.) and durability by combining the above, and also has excellent work efficiency, and the present invention has been made based on this finding. It is. Therefore, an object of the present invention is to provide a method for producing a harmful substance removing member which can be efficiently coated without using a solvent and has excellent toxic substance removing performance and durability.

[0006]

The above objects of the present invention are attained by the following inventions.

(1) A mixture of a metal powder or a polymer powder coating and a photocatalytic substance is conveyed in a gas stream, and the mixture is heated and melted. The obtained molten mixture is sprayed on the surface of a support member to form a coating layer. A method for producing a harmful substance removing member, characterized in that the member is formed. (2) In forming the coating layer, after forming the first layer including the coating layer of the metal powder or the polymer powder coating on the support member,
2. The method for producing a harmful substance removing member according to claim 1, wherein a second layer comprising a coating layer of a mixture of a metal powder or a polymer powder coating material and a photocatalytic substance is formed on the first layer. . (3) The photocatalytic substance has a specific surface area of 10 to 300 m ² / g.
3. The method for producing a harmful substance removing member according to the above item 1 or 2, wherein the material is titanium dioxide. (4) The coating according to any one of (1) to (3) above, wherein the coating layer of the mixture of the metal powder or the polymer powder coating material and the photocatalytic substance has a thickness of 0.2 to 5 mm. A method for manufacturing a harmful substance removing member. (5) The method for producing a harmful substance removing member according to any one of (1) to (4), wherein the polymer powder coating is a transparent polymer powder coating. (6) The above-mentioned items 1 to 5, wherein an inorganic powder having an average particle diameter of 1 to 20 μm is added as a light-transmitting substance to a mixture of a metal powder or a polymer powder coating material and a photocatalytic substance. The method for producing a harmful substance removing member according to any one of the above.

As described above, according to the method for producing a harmful substance removing member of the present invention, a mixture of a metal powder or a polymer powder coating material and a photocatalytic substance is conveyed in a gas stream, and the mixture is heated and melted. The mixture is sprayed onto the surface of the support member to form a coating layer, and a coating of a metal powder or a polymer powder coating material and a photocatalytic substance is coated on the support member with a thick coating layer by such a coating method. It has a particularly remarkable effect that it can be easily formed and has excellent harmful substance removal performance and durability.

In the method for producing a harmful substance removing member according to the present invention, a first layer comprising a coating layer of a metal powder or a polymer powder coating is formed on a supporting member when forming the coating layer.
By forming a second layer comprising a coating layer of a mixture of a metal powder or a polymer powder coating material and a photocatalytic substance on the first layer, a durable coating is formed and the surface layer contains titanium dioxide. Since the layer is formed, the performance of removing harmful substances can be improved.

[0010] In the present invention, the specific surface area of titanium dioxide is a photocatalyst material, to obtain excellent further NOx purification performance by a 10 to 300 m ² / g.
Further, in the present invention, the thickness of the coating layer of the mixture of the metal powder or the polymer powder coating material and the photocatalyst substance is 0.2 to 5 m.
m, and the formation of such a thick layer became possible for the first time, especially by using a thermal spray coating method.

In the present invention, the polymer powder coating is not only easily colored by being a transparent polymer powder coating, but also, when formed in two layers, by coloring the lower layer to form the upper layer. This has an excellent effect of not adversely affecting the harmful substance removing performance of the photocatalytic substance-containing layer. Further, in the present invention, sufficient light is supplied to the photocatalytic substance by adding an inorganic powder having an average particle diameter of 1 to 20 μm as a light-transmitting substance to a mixture of a metal powder or a polymer powder coating material and a photocatalytic substance. Therefore, harmful substance removal efficiency can be improved. The amount of the translucent substance to be added is 5 to 200 parts by weight, preferably 3 to 100 parts by weight of the metal powder or the polymer powder coating.
It is 0-100. Within this range, an optimal photocatalytic function can be exhibited without impairing durability.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

The method for producing a harmful substance removing member according to the present invention comprises:
A mixture of a metal powder or a polymer powder coating and a photocatalytic substance is transported in a gas stream and the mixture is heated and melted,
The obtained molten mixture is sprayed on the surface of the support member to form a coating layer. Here, the support member is not particularly limited, but a material for building civil engineering is particularly preferable, and a cement member, Various boards and metal materials, and concrete examples of the cement-based member include mortar, concrete, slate, and an extruded product. Further, as various boards, gypsum slag, silica plate, wood chip cement plate, ALC (lightweight cellular concrete), etc. are preferable, and further, as metal materials, aluminum plate, stainless steel plate,
Iron plates and the like are preferred. In addition, the support member may be ceramics, glass, or the like. The harmful substance removing member is
It has a function of effectively removing harmful substances, and the harmful substances usually include NOx, SOx mercaptans, ammonia, phosphorus, hydrogen sulfide, amines, ethylene and the like.

The photocatalyst used in the present invention is a kind of semiconductor substance, and specifically, a metal such as tin dioxide, zinc oxide, tungsten trioxide, cerium oxide, titanium dioxide, barium titanate, and ferric oxide. Oxides: zinc sulfide,
Metal chalcogenites such as cadmium sulfide, lead sulfide, zinc selenide, and cadmium selenide; Group IV metals such as silicon and germanium; compounds of Group III elements and Group V elements such as gallium phosphide, gallium arsenide, and indium phosphide And the like. Of these, more preferred are titanium dioxide, zinc oxide, selenium oxide, and tungsten trioxide. These may also have V,
Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, A
By combining at least one metal and / or metal compound selected from the group consisting of g, Pt and Au, the harmful substance removing performance can be further improved.

In the present invention, when titanium dioxide is used as the photocatalytic substance, the surface area of titanium dioxide is 1
When it is 0 to 300 m ² / g, the harmful substance removal performance can be maximized, so that it is preferable. More preferably, the surface area is from 180 to 280 m ² / g.

In the present invention, a metal powder or a polymer powder coating is used as a binder for coating or fixing the photocatalyst substance on the support member as described above. A coating is obtained. In addition, these binders are applied to the support member using thermal spraying technology,
Good performance in removing harmful substances and durability. Metal powders that can be used for this thermal spraying include aluminum, copper, aluminum alloys (for example, duralumin, lauter, Y platinum), bronze (bronze), brass (brass), gold, silver, and the like. Examples of the polymer powder coating include thermoplastic resins such as fluororesin (particularly preferably 4-fluoroethylene resin), ethylene vinyl acetate, polypropylene resin, polyethylene, and polybutene. Examples thereof include a thermosetting epoxy resin.

In the method for producing a harmful substance removing member according to the present invention, the weight ratio of the mixture of the metal powder or the polymer powder coating and the photocatalyst substance is set to the metal powder or the polymer powder coating.
The photocatalyst is 2 parts by weight to 200 parts by weight with respect to 00 parts by weight. More preferably, metal powder or polymer powder coating 1
The photocatalyst is 5 parts by weight to 100 parts by weight with respect to 00 parts by weight. Beyond these ranges, it is not practical.

In the present invention, a mixture of a metal powder or a polymer powder coating material and a photocatalytic substance is conveyed in a gas stream, the mixture is heated and melted, and the obtained molten mixture is sprayed on the surface of the support member to form a coating layer. This is a method for producing a harmful substance removing member that forms a photocatalytic substance such as titanium dioxide without melting when a metal powder is used as a binder, and the metal powder can be melted by a combustion gas. Is not particularly limited as long as it has, various metal powders can be used, but preferably, it is durable and as described above, aluminum, copper, gold,
Silver and their alloys are used.

In the heating and melting of the mixture of the metal powder and the photocatalytic substance, the mixture may be heated and melted and then sprayed on a supporting member. However, preferably, the mixture is introduced into a combustion gas together with air and heated. It is preferable to melt,
Further, it is preferable to cover the surface of the support member by spraying the combustion gas.

In the present invention, when a polymer powder coating is used as a binder, a photocatalytic substance such as titanium dioxide does not melt, and the polymer powder coating can melt with a combustion gas. There is no particular limitation as long as it has a melting point, and various polymer powder coatings can be used, but a polymer in which the binder is resistant to decomposition and deterioration due to the catalytic action of titanium dioxide. Powder coatings are preferred, but by providing a thick coating, the
Even if it is removed, a polymer powder coating may be used in which a new photocatalyst is exposed each time and the harmful substance removing function can be maintained for a long time. In the former, fluororesins, especially 4
Fluorinated ethylene resin is exemplified, and in the latter, ethylene vinyl acetate, polypropylene resin, polyethylene, polybutene and the like are exemplified.

In the present invention, the thickness of the coating layer is
It is preferably from 0.2 to 5 mm, particularly preferably from 0.2 to 1 mm when using metal powder, and from 1 to 5 mm when using a polymer powder coating. When the number of the coating layers is two, the thickness can be adjusted variously within the range of 0.2 to 5 mm, and it is particularly preferable that the thickness of the photocatalytic substance-containing layer be 0.2 to 4 mm. However, the first layer is not particularly limited, and the thickness of the coating layer is 0.2 to 5 m.
m.

FIGS. 1 and 2 show an apparatus used for spraying a mixture of a metal powder or a polymer powder coating material and a photocatalytic substance onto a supporting member by such a method (hereinafter referred to as a thermal spraying machine). Thermal spraying machine.

FIG. 1 is a cross-sectional view showing the tip of a nozzle of a thermal spraying machine used in the present invention, and FIG. 2 is a cross-sectional view showing a thermal spraying machine having a switching valve capable of switching the type of a spray. FIG. 3 is a sectional view showing a coating layer formed by the nozzle shown in FIG. 1, and FIG. 4 is a sectional view showing a coating layer formed by the nozzle shown in FIG. 1 and 3, reference numeral 1 denotes a nozzle of a thermal spraying machine, and reference numeral 2 denotes a supply hole for a mixed powder. Outside the powder supply hole 2, a convey air discharge hole 3 and a combustion gas supply hole 4 are formed concentrically, and the mixture powder as described above is conveyed by this convey air and further to the outside. Heated by the flame 6 of the fuel gas supplied from a certain combustion gas supply hole 4, the fuel gas is melted to be in a molten state 5, and is sprayed and adhered to the surface of the support member 8 to form a coating layer 7. Reference numeral 71 in the coating layer is titanium dioxide, and reference numeral 72 is a metal or resin.

In FIGS. 2 and 4, a switching valve 9 is provided at the rear of the powder supply hole, and the switching valve 9 is used to switch between the flow paths 21 and 22. Different types of powder can be supplied to the flow paths 21 and 22, respectively. For example, a powder mixture containing no photocatalyst substance is supplied from the flow path 21 to cover the support member.
forming a first layer indicated by a, and then switching the flow path to 22 to supply a powder mixture containing the photocatalytic substance supplied from the flow path 22, and further forming a first mixture indicated by reference numeral 7b on the first layer. Two layers are formed. Thereby, the coating layer 7 having a two-layer structure can be easily obtained. The thermal spraying machine shown in FIGS. 1 and 2 is used for a gas type thermal spraying method.
A plasma spraying method may be used. From the viewpoint of cost, gas spraying is preferred.

In the present invention, when the powder mixture as described above is coated on the support member by the thermal spraying technique, the surface of the support member may be cleaned or blasted. By this blasting, fine irregularities are formed on the surface of the support member, and the adhesion between the surface and the metal coating layer or the resin coating layer can be improved. This blast treatment is a well-known technique in the surface treatment technical field, and examples thereof include sand blast and shot blast.

[0026]

In the present invention, the binder powder is conveyed by a gas stream, introduced into a flame, heated by the flame of the combustion gas to be in a molten state, and sprayed on a supporting member to adhere to the surface in a molten state. So it can be firmly bonded,
Therefore, a product excellent in durability can be obtained. When the binder powder is a metal powder, the binder powder has a unique metallic luster, does not discolor or fade even when exposed outdoors for a long time, and does not deteriorate the harmful substance removing function. When the binder powder is a polymer powder coating, a fluororesin, particularly an ethylene tetrafluoride resin, has excellent durability, and the harmful substance removing function is maintained for a long time. Even if the binder deteriorates due to the photocatalytic substance, the coating layer can be easily formed thick by thermal spraying technology, and the surface reacts with the photocatalytic substance, decomposes and is removed, and a new surface appears. Maintained for a period.

The harmful substance removing member obtained by the production method of the present invention preferably removes NOx, SOx mercaptans, ammonia, phosphorus, hydrogen sulfide, amines, ethylene and the like under light irradiation, Purification, water purification,
Used for antibacterial / antifungal and antifouling applications.

[0028]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

[Examples 1 to 3] A titanium oxide coating layer was formed on the surface of a cement-based mortar flat plate (10 × 10 × 2 cm thick) by using a thermal spraying method. First, a layer having a thickness of 1.2 mm was formed as a first layer on the surface of a flat plate by spraying a layer made of ethylene-vinyl acetate using a thermal spraying apparatus.
Then, after switching the switching valve of the nozzle of the thermal spraying device, the second
A layer having a thickness of 0.5 mm was formed by spraying a mixture of titanium dioxide and a fluororesin powder of ethylene tetrafluoride as a layer. Table 1 shows the composition of the second layer and the results obtained. The temperature of the thermal spray immediately after thermal spraying was 550 ° C. The titanium dioxide used here is an anatase type manufactured by Sakai Chemical Co., having a specific surface area of 220 m ² / g.

Example 4 An aluminum plate (10 × 10
X thickness 2 cm), a titanium oxide coating layer was formed by thermal spraying. First, titanium powder was mixed with aluminum powder (purity: 99%) on the surface of an aluminum plate and sprayed. At this time, the thickness of the coating layer was 0.5 mm.
The temperature immediately after the thermal spraying was 760 ° C. The titanium dioxide used was the same as that used in Examples 1-3.
Table 1 shows the composition of the coating layer and the results obtained.

[0031]

[Table 1]

Comparative Example Cement mortar flat plate (10
The surface of (× 10 × 2 cm thick) was spray-coated by mixing titanium dioxide with a fluororesin paint (ethylene tetrafluoride). The thickness of the coating layer was 0.05 mm. Table 1 shows the composition of the coating layer and the results obtained.

[Abrasion resistance test method] The abrasion resistance was measured in accordance with the chain-type labeling test method according to the asphalt pavement procedure. When a layer containing titanium dioxide disappeared using a labeling tester manufactured by Yantou Machinery Co., Ltd. The time was evaluated.

[NO Removal Performance Test Method] In this test method, NOx purification performance was measured using NOx gas as a harmful substance. This NOx purification performance was measured using a flow type NOx meter manufactured by Monitor Lab Co., Ltd. according to the principle shown in FIG.
The removal rate was measured. In the test, the specimen was placed in a cell, and 0.3 liter / min of NO gas with a NO concentration of 1 ppm was flowed from the inlet, and after passing through the cell in which the specimen was set, the NO and NO ₂ concentrations coming out of the outlet were measured. Was measured, and the NOx removal rate was calculated from the following equation. The cell was irradiated with ultraviolet light having a wavelength of 360 nm and an intensity of 500 μw / m ² . The NOx removal rate was measured immediately after the preparation of the test piece and after 6 months of exposure to the outdoors, and the persistence of NOx purification performance was examined.

[0035]

(Equation 1)

Example 5 A cement-based mortar plate (1)
A titanium oxide coating layer was formed on the surface (0 × 10 × 2 cm thick) by using a thermal spraying method. As a coating layer on the surface of a flat plate,
Mixing titanium dioxide with ethylene-vinyl acetate,
Thermal spraying was performed using a thermal spraying apparatus to form a layer having a thickness of 1.5 mm. The temperature of the thermal spray immediately after thermal spraying was 520 ° C.
The titanium dioxide used was an anatase type manufactured by Sakai Chemical Co., Ltd., having a specific surface area of 220 m ² / g. Table 2 shows the obtained results. When the surface was exposed outdoors for 6 months, the surface was slightly peeled off by rubbing the surface with a wire brush, and a new surface was exposed. The NOx purification performance was also measured.

[0037]

[Table 2]

[0038]

According to the method for producing a harmful substance removing member of the present invention, a mixture of a metal powder or a polymer powder coating and a photocatalytic substance is transported in a gas stream, and the mixture is heated and melted. Is sprayed onto the surface of the support member to form a coating layer. By such a coating method, a mixture of a metal powder or a polymer powder coating material and a photocatalytic substance can be easily applied to the support member to form a thick coating layer. And has a particularly remarkable effect that a material excellent in harmful substance removal performance and durability can be obtained.

In the method for producing a harmful substance removing member according to the present invention, the first layer comprising the coating layer of the metal powder or the polymer powder coating is formed on the supporting member when forming the coating layer.
By forming a second layer comprising a coating layer of a mixture of a metal powder or a polymer powder coating material and a photocatalytic substance on the first layer, a durable coating is formed and the surface layer contains titanium dioxide. Since the layer is formed, the performance of removing harmful substances can be improved.

In the present invention, the polymer powder coating is not only easily colored by being a transparent polymer powder coating, but also, when formed in two layers, by coloring the lower layer to form the upper layer. This has an excellent effect of not adversely affecting the harmful substance removing performance of the photocatalytic substance-containing layer. Further, in the present invention, sufficient light is supplied to the photocatalytic substance by adding an inorganic powder having an average particle diameter of 1 to 20 μm as a light-transmitting substance to a mixture of a metal powder or a polymer powder coating material and a photocatalytic substance. Therefore, harmful substance removal efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a thermal spraying device of the present invention.

FIG. 2 is a partial sectional view showing a thermal spraying apparatus having the switching valve of the present invention.

FIG. 3 is a cross-sectional view showing a harmful substance removing member obtained by the thermal spraying method of the present invention.

FIG. 4 is a sectional view showing another example of the harmful substance removing member obtained by the thermal spraying method of the present invention.

FIG. 5 is a schematic sectional view showing a testing device for a harmful substance removing member of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Nozzle part 7a 1st coating layer 2 Powder supply hole 7b 2nd coating layer 3 Conveying air discharge hole 21,22 Channel 4 Combustion gas supply hole 71 Titanium dioxide 5 Powder 72 Metal or resin powder 6 Combustion flame 8 Support Member 7 Coating layer 9 Switching valve

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI E04C 2/30 B01D 53/36 E

Claims (6)

[Claims] 1. A mixture of a metal powder or a polymer powder coating material and a photocatalytic substance is transported in a gas stream, and the mixture is heated and melted, and the obtained molten mixture is sprayed on a surface of a support member to form a coating layer. A method for producing a harmful substance removing member. 2. A method for forming a coating layer, comprising: forming a first layer comprising a coating layer of a metal powder or a polymer powder coating on a supporting member; and forming a metal powder or a polymer powder coating on the first layer. The method for producing a harmful substance removing member according to claim 1, wherein a second layer comprising a coating layer of a mixture with a photocatalytic substance is formed. 3. The photocatalytic substance has a specific surface area of 10 to 300 m.
² / g of titanium dioxide.
Alternatively, the method for producing a harmful substance removing member according to claim 2. 4. The coating layer according to claim 1, wherein the coating layer of the mixture of the metal powder or the polymer powder coating and the photocatalytic substance has a thickness of 0.2 to 5 mm. Production method of harmful substance removing member. 5. The method for producing a harmful substance removing member according to claim 1, wherein the polymer powder coating is a transparent polymer powder coating. 6. A mixture of a metal powder or a polymer powder coating material and a photocatalytic substance, as a translucent substance, having an average particle size of 1 to 20 μm.
The method for producing a harmful substance removing member according to any one of claims 1 to 5, wherein an inorganic powder of m is added.