JP2000061313A - Photocatalytic sheet structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a photocatalytic sheet stably for a long period of time by a method wherein a metal-made edge piece is attached to an edge of a mesh shaped photocatalytic sheet wherein a photocatalytic particle-containing resin layer is provided to a surface of a mesh-like supporting base material, and the sheet is formed by bending. SOLUTION: A photocatalytic particle-containing polytetrafluoroethylene burnt layer 12 is provided to a surface of a mesh like supporting base material 11 of, for example, a plain weave glass cloth or the like. Both ends of a width of a band body of the obtained mesh-like photocatalytic sheet 1 are fringed by a metal-made edge piece 2, that is folded in a bellows form, and the bellows body 10 is fixed onto, for example, an aluminum sheet by a suitable means (for example, a click is provided to the aluminum sheet, and the click is folded down by passing through the mesh.). For fringing by the metal made edge piece 2, a metallic tape with a hot melt based adhesive on one side is folded by making an adhesive surface inside along almost a center of the width, that is covered on a width edge of the mesh-like photocatalytic sheet 1, and fixed to the edge of the mesh-like photocatalytic sheet 1 by the hot melt based adhesive by thermally pressurizing with a hot platen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalyst sheet structure, which is useful for reducing / removing the concentration of bad odors and harmful gases, or for air purification such as antibacterial.

[0002]

2. Description of the Related Art As is well known, when a metal oxide semiconductor such as titanium oxide is irradiated with ultraviolet rays, electrons in the valence band jump to the conduction band to generate holes, which come into contact with the surface under this excited state. Active species (radicals) are generated from oxygen and water,
The active species oxidize and decompose organic substances, microorganisms, etc. attached to the surface.

Therefore, it is known to utilize the oxidative decomposition action of a metal oxide semiconductor such as titanium oxide, that is, photocatalyst particles, to deodorize or purify air in a living space or a workplace. For example, deodorization of new car odors, deodorization of cigarette odors, or volatile organic compounds (VO) in new houses, etc.
It is known to reduce or remove the concentration of C).

Conventionally, as a photocatalyst sheet, a mesh-shaped photocatalyst sheet in which a resin layer containing photocatalyst particles is provided on the surface of a plain weave glass cloth substrate is known (Japanese Patent Laid-Open No. 3-1064).
No. 20). With this mesh-shaped photocatalytic sheet, the ventilation resistance can be kept sufficiently low to purify the circulating air, and the ultraviolet rays that have passed through the ventilation holes can be reflected by a reflecting mirror to perform a photocatalytic action on the entire surface of the mesh. There is an advantage of.

[0005]

The photocatalyst particles can semi-permanently perform an oxidative decomposition action by photoexcitation. However, in the mesh-shaped photocatalyst sheet using the plain weave glass cloth as a supporting substrate, the resin of the photocatalyst particle-containing resin layer is decomposed and deteriorated by the excited photocatalyst particles after a long period of time, and the binding at the intersection of the glass cloth is unraveled. The edges of the glass cloth are easily broken and broken. It is conceivable to perform edging in order to prevent the loosening of the edge of the glass cloth, but in the case of ordinary edging, there is a fear that the edging material is decomposed and deteriorated by the excited photocatalytic particles for a long period of time corresponding to the semi-permanent life of the photocatalytic particles. is there.

When the mesh-shaped photocatalyst sheet is used by being bent into a bellows shape or the like, when the supporting base material of the photocatalyst sheet is made of a material such as glass cloth which is not easily plastically deformed, the bending is performed. The bending shape is retained by the rigidity of the edging member shaped according to the shape, but when the edging material is decomposed and deteriorated by the excited photocatalyst particles over a long period of time and its rigidity is reduced, the bending It is difficult to expect shape retention.

The inventors of the present invention have found that the photocatalyst layer obtained by applying a dispersion of polytetrafluoroethylene powder and photocatalyst fine particles and baking the applied layer exhibits remarkably excellent air purification performance. We have already proposed a mesh-shaped photocatalyst sheet in which a polytetrafluoroethylene resin-containing baked layer containing photocatalyst particles is provided on the surface of a mesh-shaped supporting substrate. In the photocatalyst layer of the mesh-shaped photocatalyst sheet, a gap layer exists between the photocatalyst fine particles and the resin, and the gap layer is connected to form a communication path. This is due to the significant difference in heat shrinkage between polytetrafluoroethylene and photocatalyst titanium oxide fine particles and the non-adhesiveness of polytetrafluoroethylene, which causes a large heat shrinkage stress at the interface during cooling during firing and heating. This is because interfacial debonding occurs due to the large tensile stress due to the non-adhesiveness of the photocatalyst particles. As a result of increasing the contact area of the photocatalyst particles with the air due to the communication gap, the air purification efficiency is enhanced. .
In this mesh-shaped photocatalyst sheet, since the resin of the photocatalyst layer is chemically extremely stable polytetrafluoroethylene, it is expected that the mesh-shaped photocatalyst sheet will have a longer life. Considering the decomposition and deterioration of the material due to excited photocatalyst particles, it is difficult to complete its long life.

The object of the present invention is to stabilize a photocatalyst sheet provided with a resin layer containing photocatalyst particles on a mesh-like support base material, particularly a photocatalyst sheet provided with a baking layer of polytetrafluoroethylene resin containing photocatalyst particles for a long period of time. Another object of the present invention is to provide a photocatalytic sheet structure that can be maintained at a high temperature.

[0009]

One photocatalyst sheet structure according to the present invention is made of metal on the edge of a mesh-shaped photocatalyst sheet in which a resin layer containing photocatalyst particles is provided on the surface of a mesh-shaped supporting base material. The edge piece is attached and the sheet is formed by bending.

Another photocatalytic sheet structure according to the present invention is
A mesh-shaped photocatalyst sheet having a photocatalyst particle-containing resin layer provided on the surface of a mesh-shaped supporting substrate is stacked, and a metal edge piece is clasped to an end of the superposed body. is there.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A shows a mesh-shaped photocatalytic sheet in the photocatalytic sheet structure according to the present invention.
1B is a cross-sectional view taken along line A-B of FIG. In FIG. 1, 11 is a mesh-shaped supporting base material, and for example, plain weave glass cloth can be used.
Reference numeral 12 is a photocatalyst particle-containing polytetrafluoroethylene calcination layer adhered to the mesh-shaped support substrate 11, and a dispersion in which polytetrafluoroethylene powder and photocatalyst particles are contained is applied, and the solvent in the applied layer is heated. Are removed by evaporation, and the polytetrafluoroethylene particles are sintered by heating and firing, and then cooled.

During this cooling, the heat shrinkage of the polytetrafluoroethylene resin is greater than that of the photocatalyst particles, and the non-fusing property of the polytetrafluoroethylene resin to the photocatalyst particles causes a gap between the photocatalyst particles and the polytetrafluoroethylene resin. An interstitial layer is created in the. Thus, in the photocatalyst particle-containing polytetrafluoroethylene firing layer 12,
The photocatalyst particles are dispersed in the sintered layer of the sintered polytetrafluoroethylene powder, minute gaps are formed between the resin and the photocatalyst particles, and these are connected to form a chain structure. The thickness of this gap is a fine gap of several nanometers to several microns, and air can sufficiently flow in and out due to the chain structure.

Therefore, the contact area between the photocatalyst particles and the air per unit area of the photocatalyst layer (12) is large due to the chain gap at the interface between the photocatalyst particles and the polytetrafluoroethylene resin binder, and thus the mesh shape is obtained. Even if the mesh of the supporting substrate is considerably large, it is possible to efficiently perform oxidative decomposition by contact with photocatalyst particles of organic substances and microorganisms contained in the air, and because of the mesh having a relatively large mesh-shaped photocatalytic sheet. Air can be circulated with a low flow resistance, and the air can be efficiently purified under smooth air circulation.

It is also possible to apply a polytetrafluoroethylene calcination layer containing no photocatalyst particles to the mesh-shaped supporting substrate 11 and to provide a photocatalyst particle-containing polytetrafluoroethylene calcination layer on this layer.

As the mesh-shaped supporting base material 11,
Flexibility, heat resistance, high strength, and porosity of 10-8
If the requirements such as 0%, preferably 40 to 70% (below 10%, the air flow resistance becomes too high, and above 80%, the air contact area becomes too small and the air purification efficiency becomes low), etc. In addition to the above plain woven glass cloth, for example, a wire mesh (for example, aluminum wire mesh) or a heat-resistant plastic sheet (for example, polyimide or polytetrafluoroethylene) is perforated by punching holes at the above porosity. Sheet (hole shape is square, hexagon, triangle,
It is also possible to use a woven fabric of a heat-resistant organic fiber (for example, a polyamide fiber) or the like, such as a circular shape or an oval shape.

As the photocatalyst particles, titanium oxide, strontium titanate, tungsten oxide, zinc oxide,
Tin oxide, cadmium sulfide, etc. can be mentioned,
It is preferable to use the anatase type titanium oxide fine particles exhibiting the most excellent photocatalytic activity. Further, in order to enhance the activity of the photocatalyst particles, alkali metal ions can be supported.

The particle size of the above polytetrafluoroethylene powder is 0.2 to 0.3 μm, and the particle size of the photocatalyst particles is 0.
007 to 0.5 μm, and the porosity of the chain gap structure of the photocatalyst particle-containing polytetrafluoroethylene calcination layer is usually 5 to 30%.

If the amount of the photocatalyst particles in the above-mentioned photocatalyst particle-containing polytetrafluoroethylene calcination layer 12 is too large, the binding strength between the photocatalyst particle-containing polytetrafluoroethylene calcination layer 12 and the supporting substrate 11 will be insufficient and the amount will be small. If it is too much, the air purification efficiency becomes insufficient, so the mixing ratio of polytetrafluoroethylene powder / photocatalyst particles is 1/9 to 7 /.
3, preferably 3/7 to 6/4.

A dipping method is usually used for coating each of the above dispersions, but a method of spraying the dispersion, a method of brush coating the dispersion, and the like can also be used. The concentration of this dispersion is set according to the coating method, but is usually 40% to 60%.

At least one of activated carbon particles, zeolite particles, and silica gel particles can be added to the photocatalyst particle-containing polytetrafluoroethylene calcination layer 12 of the mesh-shaped photocatalyst sheet together with the photocatalyst particles. It is also possible to add a colorant such as carbon black together with the photocatalyst particles.

FIG. 2 shows an example of the photocatalyst sheet structure according to the present invention, in which both ends of the width of the above-mentioned strip of mesh-like photocatalyst sheet are edged with metal edge pieces 2 and formed into a bellows shape. The bellows body 10 is bent and fixed to the light reflecting plate 3, for example, an aluminum plate, by an appropriate means (for example, a claw is provided on the aluminum plate and the claw is passed through a mesh and folded). Figure 3
Shows another example of the photocatalyst sheet structure according to the present invention, in which the width ends of the strip of the mesh-like photocatalyst sheet described above are edged with metal edge pieces 2, and this is bent into a bellows body 10, The bellows body 10 is covered with a mesh-shaped protective sheet 4.

In the embodiment shown in FIGS. 2 and 3, for edging with the metal edge piece 2, a metal tape having a hot melt adhesive applied on one side is provided along the approximate center of the width and the adhesive surface is placed inside. Then, the bent metal tape is covered on the width edge of the mesh-shaped photocatalyst sheet, and the bent metal tape is heated and pressed by a hot plate so that the bent metal tape is mesh-shaped photocatalytic sheet with a hot-melt adhesive. A method of fixing to the edge can be used.
The metal edge piece 2 has higher bending rigidity and lower elastic limit than the mesh-shaped photocatalyst sheet 1, and the bending elastic reaction force of the mesh-shaped photocatalyst sheet 1 is equal to that of the metal edge piece 2. It is rigidly supported and maintains the overall bellows shape.

In the photocatalyst sheet structure shown in FIGS. 2 and 3, the flowing air passes through the mesh-shaped photocatalyst sheet a number of times with respect to the air flow in the lengthwise direction of the bellows, and the air flows in the meantime. Purified. In particular, in the embodiment shown in FIG. 2, light can be irradiated to the photocatalyst layer of the mesh-shaped photocatalyst sheet 1 from multiple directions due to the reflection plate 2, so that the air purification efficiency can be improved in terms of light irradiation efficiency. . In the embodiment shown in FIG. 3, the mesh-shaped photocatalytic sheet 1 can prevent direct contact of other substances with the mesh-shaped protective sheet 4, and the photocatalytic layer can be stably held. Suitable for frequent use.

FIG. 4 shows another example of the photocatalyst sheet structure according to the present invention, in which the mesh-shaped photocatalyst sheets 1a and 1b having different widths are superposed, and the both ends of the superposition are aligned to form a metal edge. I'm wearing two pieces together. For the clasping by the metal edge piece 2, a metal tape, for example, a stainless tape is bent along the center of the width, and is temporarily attached to the overlapping end of the photocatalyst sheet. It is possible to use a method in which keyaki holes are formed at short intervals in the longitudinal direction to integrate the metal tape and the end portion of the overlapping mesh photocatalytic sheet.

In this embodiment, the wide mesh photocatalytic sheet 1a is bent in a curved shape with respect to the narrow mesh photocatalytic sheet 1b, and the bending stress is supported by the rigidity of the metal edge piece 2. Has been done.

As the metal edge piece 2, aluminum alloy tape, copper alloy tape, stainless tape or the like can be used.
The rigidity (rigidity higher than that of the mesh-shaped photocatalytic sheet) is set by adjusting the thickness. The above mesh-shaped protective sheet 4
Include metal nets (for example, nets of aluminum, copper, stainless steel, etc.) and resin nets (for example, polypropylene, polyethylene, polyethylene terephthalate, polytetrafluoroethylene, etc. In addition to extruded products)], synthetic resin fibers, metal fibers, and other woven and non-woven fabrics can also be used. The bent body 10 may have, for example, a cylindrical shape, in addition to the bellows shape.
Examples thereof include an elliptic column shape, an arc shape, a spiral shape, an umbrella shape, and a spiral shape.

In the photocatalyst sheet structure according to the present invention, the edge piece supporting the bent shape of the mesh-shaped photocatalyst sheet against the bending reaction force is made of metal, and the excited photocatalyst is decomposed. The rigidity of the edge piece can be stably maintained even under the action, and the shape of the mesh-shaped photocatalytic sheet can be maintained at the shape suitable for air purification even after a long period of time, so that the efficiency is stable and long-term. It can purify the air. .

In particular, in the above embodiment, the photocatalyst particle-containing resin layer 12 is a photocatalyst particle-containing polytetrafluoroethylene calcination layer, and the mesh is used for the stability of the polytetrafluoroethylene calcination layer against the excited photocatalyst. It is possible to stably hold the crossing points of the linear supporting substrate 11, prevent the warp yarns and the weft yarns from being displaced, and keep the mesh in the initial state, and the air passes through not only the exposed photocatalyst particles on the surface of the photocatalyst layer but also the chain gap. Since the photocatalyst particles inside can also be brought into contact with each other, the air purification efficiency can be further improved.

The photocatalyst sheet structure according to the present invention is used, for example, in the vicinity of a window in a vehicle for deodorizing a new vehicle odor or a cigarette odor, or a volatile organic compound in a new house or the like ( It can be used for concentration reduction / removal of VOC). Out of that
It can be installed in a refrigerator and used to decompose and remove ethylene, which accelerates the ripening of fruits and agricultural products.

Although sunlight is usually used as an ultraviolet ray source for exciting the photocatalyst particles, in some embodiments, a fluorescent lamp, a black light bull-lamp, a halogen lamp, or a xenon lamp that emits ultraviolet rays having a wavelength of 400 nm or less is used. A flash lamp, a mercury lamp, a germicidal lamp, etc. can also be used.

[0031]

EXAMPLE 1 A photocatalytic sheet structure having the structure shown in FIG. 1 was used, in which polytetrafluoroethylene powder (particle size: approximately 0.25 μm) and anatase type titanium oxide fine particles (particle size: 0. After immersing the plain weave glass cloth in a dispersion having a solid content concentration of 40% with (007 μm), 110 ° C. ×
After removing the water for 60 seconds and firing at 370 ° C. for 100 seconds to form a photocatalyst particle-containing polytetrafluoroethylene firing layer, the amount of titanium oxide supported was 30 g / m ² , porosity 53%, and thickness 0.1. A 5 mm mesh photocatalytic sheet is cut into a width of 120 mm and a length of 220 mm, and an aluminum tape with a thickness of 0.2 mm and a width of 20 mm on both sides of the width is rimmed by bending and thermocompression bonding. And then bent into a bellows shape in the lengthwise direction (dimensions after bending are 120 mm x 120 mm x 18 mm),
Further, a 120 mm × 120 mm light reflecting aluminum sheet was attached.

This photocatalyst sheet structure is installed under the rear window of an ordinary sedan car with a strong new vehicle odor, and the car is parked in a place where it is exposed to the sunlight in fine weather, and the door is opened 3 hours after the start of parking. When the presence or absence of new car odor was examined, almost no new car odor was felt.

A photocatalytic sheet structure was obtained in the same manner as above except that the polytetrafluoroethylene in the dispersion was replaced with a perfluoroalkylvinylether-tetrafluoroethylene copolymer. When a new car odor was inspected under the same conditions as above, a new car odor was slightly felt, and the effect of the chain gap of the photocatalyst particle-containing polytetrafluoroethylene firing layer as the photocatalyst layer was confirmed.

[Comparative Example 1] The same as Example 1 except that a transparent polypropylene edge piece was used in place of the metal edge piece. When this comparative example product was tested for durability with a Sunshine weather meter (Suga tester),
At 236 hours the polypropylene strips started to collapse. In particular, the disintegration at the contact surface between the photocatalytic sheet on the side exposed to the light and the polypropylene resin was fast, and the disintegration started from 180 hours. Of course, the same test was performed for Example 1, but
No decomposition of the edge piece or collapse of the structure was observed.

From the measurement results, in the photocatalyst sheet structure according to the present invention, the edge pieces of the photocatalyst sheet structure can be stably held even under the action of decomposing the excited photocatalyst, and the mesh-shaped photocatalyst sheet can be obtained even after a long period of time. It was confirmed that the shape could be maintained at the initial shape suitable for air purification.

[Embodiment 2] A photocatalytic sheet having the structure shown in FIG.
A flat woven glass cloth is used as a dispersion of polytetrafluoroethylene powder (particle size: approximately 0.25 μm) and anatase type titanium oxide fine particles (particle size: 0.007 μm) having a solid content concentration of 40%. 110 ° C after immersion
After removing water for 60 seconds, the mixture was baked at 370 ° C. for 100 seconds to form a baked layer of photocatalyst particle-containing polytetrafluoroethylene. The amount of titanium oxide supported was 30 g / m ² , the porosity was 53%, and the thickness was 0. A 1 mm mesh photocatalytic sheet was cut into 200 mm x 300 mm, and polytetrafluoroethylene powder (particle size: approximately 0.25 µm), anatase type titanium oxide fine particles (particle size: 0.007 µm) and carbon black were used. After soaking the plain weave glass cloth in a dispersion having a solid content concentration of 45%, the water content was removed at 110 ° C. for 60 seconds, and the material was baked at 370 ° C. for 100 seconds to form a photocatalyst particle-containing polytetrafluoroethylene baking layer. and titanium oxide support amount 30 g / m ² was obtained, porosity 53%, Ca - carbon black loading amount 0.1 g / m ^2, a thickness of 0.5mm mesh-like photocatalyst sheet - DOO 205mm × 300mm and 20
Cut into 0 mm x 300 mm, superimpose these cutting sheets on each other, and half-fold a 20 mm wide stainless tape at each end to temporarily fix it.
It was permanently fixed at 0 mm intervals with key punched holes having a diameter of 2 mm.

With respect to this example product, the new vehicle odor was measured in the same manner as in Example 1. As a result, similar to Example 1, almost no new vehicle odor was felt.

[Embodiment 3] A photocatalytic sheet having the structure shown in FIG.
A flat woven glass cloth is used as a dispersion of polytetrafluoroethylene powder (particle size: approximately 0.25 μm) and anatase type titanium oxide fine particles (particle size: 0.007 μm) having a solid content concentration of 40%. 110 ° C after immersion
After removing water for 60 seconds, the mixture was baked at 370 ° C. for 100 seconds to form a baked layer of photocatalyst particle-containing polytetrafluoroethylene. The amount of titanium oxide supported was 30 g / m ² , the porosity was 53%, and the thickness was 0. A 0.5 mm mesh photocatalytic sheet is edged with an adhesive aluminum tape (width 20 mm, thickness 0.2 mm, hot melt adhesive) half-folded with a width of 10 mm, and further 100 mm wide, 300 mm long, high. 20m
Bending molding into a bellows body 10 of m and 15 mountains,
Thickness 0.2mm, thread thickness 0.2mm, eye size 3m
It was covered with a m × 3 mm black polypropylene net.

This photocatalyst sheet structure is installed under the rear wind of an ordinary sedan car with a strong new car smell, and this car is parked in a place where it is exposed to the sunlight under fair weather, and the door is opened 40 minutes after the start of parking. When the presence or absence of new car odor was examined, almost no new car odor was felt.

[0040]

In the photocatalyst sheet structure according to the present invention, since the metal edge piece is used as the edge piece that retains the shape of the mesh-shaped protective sheet, the semi-permanent life of the photocatalyst particles is improved. Correspondingly, the shape of the mesh-shaped protective sheet can be maintained mechanically and stably in the shape of the place that is most suitable for air flow purification, and long-term highly efficient air purification becomes possible.

[Brief description of drawings]

FIG. 1 is a view showing an example of a mesh-shaped photocatalytic sheet used in the present invention.

FIG. 2 is a view showing an example of a photocatalytic sheet structure according to the present invention.

FIG. 3 is a view showing another example of the photocatalytic sheet structure according to the present invention.

FIG. 4 is a view showing another example of the photocatalytic sheet structure according to the present invention.

[Explanation of symbols]

1 mesh photocatalytic sheet 11 Supporting material in mesh form 12 Photocatalyst layer 10 Bent formed body of mesh-shaped photocatalytic sheet 2 metal edge pieces

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tadanori Michimoto             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. (72) Inventor Satoshi Ishizaki             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. (72) Inventor Tomoko Doi             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. F-term (reference) 4G069 AA03 AA08 AA11 BA04A                       BA04B BA14B BA22A BA22B                       BA48A BB04A BB06A BC12A                       BC22A BC35A BC36A BC50A                       BC60A CA17 DA05 EA09                       EA12 EC22Y FB15

Claims (4)

[Claims] 1. A metal-made edge piece is attached to an edge of a mesh-shaped photocatalyst sheet having a resin layer containing photocatalyst particles on a surface of a mesh-shaped supporting substrate, and the sheet is bent and formed. A photocatalytic sheet structure characterized by: 2. A mesh-shaped photocatalytic sheet having a photocatalyst particle-containing resin layer provided on the surface of a mesh-shaped supporting substrate,
A photocatalyst sheet structure, characterized in that a metal edge piece is attached to an end of the superposed body. 3. The photocatalyst sheet structure according to claim 1, wherein the mesh-shaped supporting substrate is a plain woven fabric. 4. The photocatalyst particle-containing resin layer is a photocatalyst particle-containing polytetrafluoroethylene calcination layer.
The photocatalytic sheet structure according to any one of claims.