JPH11188085A - Air cleaning unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide fine deodorization and to make the unit smaller by placing an optical catalytic sheet within an optical reception area toward an ultraviolet ray generator, by forming an optical catalytic layer between a polytetrafluoroethylene resin and optical catalytic minute particles which are dispersed on the burning layer of the polytetrafluoroethylene resin, and by providing the optical catalytic layer with the support material of the optical catalytic sheet. SOLUTION: Optical catalytic sheet 1 comprises optical catalytic layer 12 whose space rate is more than 7% on mesh support material 11. In the optical catalytic later 12, optical catalytic minute particles are dispersed in the burning layer of sintered polytetrafluoroethylene powders and minute spaces are created between the resin and the optical catalytic minute particles. The optical catalytic sheet 1 can laminate deodorant sheets made mainly of one or more than two kinds of activated carbon or coppercarboxymethylcellulose. Air passes contacting a wide area of the outer surface of the optical catalytic minute particles so that deodorant components in the air can be oxidation-deodorized with activated optical catalytic minute particles by putting the optical catalytic sheet 1 on support 3, putting ultraviolet ray generator 2 between them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air purifying unit using a gas permeable photocatalyst sheet, which is useful for reducing or removing the concentration of tobacco odor and other odors and harmful gases, or for purifying air such as antibacterial. is there.

[0002]

2. Description of the Related Art As is well known, in a metal oxide semiconductor such as titanium oxide, electrons of a valence band jump up to a conduction band by irradiation of ultraviolet rays to generate holes, and contact with the surface under this excited state. Active species (radicals) from oxygen and moisture
The active species oxidize and decompose organic substances and microorganisms attached to the surface, and also oxidize nitrogen oxides and sulfur oxides to final oxides.

[0003] Therefore, ultraviolet rays are irradiated on a photocatalyst sheet in which the photocatalyst fine particles are carried by a binder, and the activated photocatalyst sheet is brought into contact with air to reduce malodor such as cigarette odor in a living space or a work place. Toxic gases such as nitrogen oxides and sulfur oxides, or volatile organic compounds (VO
It is known to perform concentration reduction / removal of C) or air purification such as antibacterial.

In order to support the photocatalyst fine particles on a support, a method of fixing the photocatalyst fine particles to the support via a binder is generally used.
Activated photocatalyst fine particles are required to be stable without being decomposed and degraded. Many prior examples are disclosed. For example, as a binder, a silicone-based polymer or a vinyl ether-fluoroolefin copolymer is used.
It has been proposed to use a fluorine-based polymer such as vinylester-fluoroolefin copolymer (JP-A-7-171408).

[0005]

Conventionally, various air purifying apparatuses using a photocatalyst sheet have been proposed (for example, JP-A-3-106420, JP-A-7-25102).
8, JP-A-7-35373, JP-A-7-28452
No. 3), in the conventional apparatus, since most of the surface of the photocatalyst particles in the photocatalyst sheet is covered with the binder resin and the contact area between the air and the photocatalyst particles is small, the air purification efficiency is low and Larger sizes and higher equipment costs are inevitable.

Accordingly, the present inventors have conducted intensive studies to improve the deodorizing performance of the photocatalyst sheet. As a result, a dispersion of polytetrafluoroethylene powder and photocatalyst fine particles was applied, and this applied layer was fired. It was found that the photocatalyst layer thus obtained exhibited remarkably excellent deodorizing performance. In order to elucidate the cause of this high deodorizing performance, the structure of the photocatalyst layer was observed with a microscope, and a void layer was present between the photocatalyst fine particles and the resin, and this void layer was connected to form a communication passage. I knew that In this photocatalyst layer, the voids are formed at the interface between the photocatalyst fine particles and the polytetrafluoroethylene resin because of the remarkable difference in the heat shrinkage between polytetrafluoroethylene and the photocatalytic titanium oxide fine particles and the non-adhesion of polytetrafluoroethylene. It is presumed that a large heat shrinkage stress is generated at the interface at the time of cooling by baking heating, and the interface is separated due to the large tensile stress due to the non-adhesiveness of the interface.

Conventionally, a photocatalyst sheet is produced by using a crosslinking agent such as a fluorine-based polymer such as vinyl ether-fluoroolefin copolymer or vinylester-fluoroolefin copolymer and an isocyanate-based curing agent, and photocatalyst fine particles. Is coated on a support, and the coated layer is cured by a crosslinking reaction (see the above-mentioned JP-A-7-171408).
However, in these methods, there is no process for generating a shrinkage stress at the interface between the photocatalyst fine particles and the resin, and it is hardly expected that voids will be generated at the interface.

[0008] The object of the present invention is to
An object of the present invention is to provide an air purifying unit using a photocatalyst sheet, which has excellent deodorizing performance and can be reduced in size and cost.

[0009]

According to the present invention, there is provided an air purification unit comprising a photocatalyst layer in which fine particles of photocatalyst are dispersed in a fired layer of polytetrafluoroethylene resin and fine voids are formed between the resin and the fine particles of photocatalyst. A photocatalyst sheet having a photocatalyst sheet on a supporting base material is provided in a light receiving region for an ultraviolet ray generator.
Activated carbon, zeolite, or copper carboxymethylcellulose used as a laminate with a deodorizing sheet containing one or more of them, and a mesh-shaped or perforated support base material was used. A gas permeable photocatalyst sheet may be bent and provided in the light receiving region for the ultraviolet ray generator, and the porosity of the photocatalyst layer is preferably 7% or more.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a photocatalyst sheet 1 used in the present invention. In FIG. 1, reference numeral 11 denotes a supporting substrate. Reference numeral 12 denotes a photocatalyst layer provided on the support substrate 11, in which fine particles of photocatalyst are dispersed in a fired layer of sintered polytetrafluoroethylene powder, and fine voids are formed between the resin and the fine particles of photocatalyst. The gaps between the tied polytetrafluoroethylene powders are connected to the void layer to form a multi-gap communication structure. The thickness of the gap between the polytetrafluoroethylene resin and the photocatalyst fine particles is a fine gap of several nanometers to several microns, and water and the like do not pass due to the water repellency of polytetrafluoroethylene. The air can flow in and out well.

FIG. 2 (A) is a drawing showing a gas permeable photocatalyst sheet used in the present invention, and FIG. 2 (B) is a cross-sectional view of FIG. 2 (A). In FIG. 2, reference numeral 11 denotes a mesh-like supporting substrate (for example, a plain-woven glass cloth);
Is a photocatalyst layer provided on the support base material 11, as described above, the photocatalyst fine particles are dispersed in the fired layer of the sintered polytetrafluoroethylene powder, and minute voids are formed between the resin and the photocatalyst fine particles. The gaps between the sintered and polytetrafluoroethylene powders are connected to the gap layer to form a multi-gap communication structure.

In order to produce the above-mentioned photocatalyst sheet, a dispersion containing polytetrafluoroethylene powder and photocatalyst fine particles is applied to a supporting substrate, and the solvent in the coating layer is removed by evaporation by heating. Further, the polytetrafluoroethylene particles are sintered by heating and firing (heating temperature is 330 ° C. or higher). At the time of cooling after the sintering, due to the heat shrinkage larger than the photocatalyst fine particles of the polytetrafluoroethylene resin and the non-fusion property of the polytetrafluoroethylene resin to the photocatalyst fine particles, the photocatalytic fine particles and the polytetrafluoroethylene resin A void layer is formed therebetween. Further, the melt viscosity of the polytetrafluoroethylene powder at the time of firing is high (10 ⁸ poise or more), the particle shape is maintained without flowing, and the firing is performed without pressure. Enough gaps remain between the ethylene powders. Therefore, the photocatalyst layer has an air-permeable multi-gap structure.

The polytetrafluoroethylene powder has a particle size of 0.1 to 1 μm, and the photocatalyst fine particles have a particle size of 200 n.
m, preferably 50 nm or less.

The porosity of the photocatalyst layer is 7% or more, especially 1%.
It is preferred to be 0% or more. The porosity x is given by x = 1− [w / (vρ)], where ρ is the true specific gravity of the photocatalytic layer and w is the weight of the volume v of the photocatalytic layer. If the porosity is less than 7%, the effect of improving the degree of contact between the air and the photocatalyst fine particles by the multi-porous structure is reduced. However, it is preferable to be 30% or less in terms of mechanical strength.

The thickness of the photocatalyst layer is 3 μm to 30 μm.
It is preferable that If it is less than 3 μm, the volume of the photocatalyst layer will be small and the deodorizing performance will be low. If it exceeds 30 μm, the gas diffusion efficiency will be reduced and the layer thickness will be unnecessarily thick. If the content of the photocatalyst fine particles in the dispersion is too large, the binding strength between the photocatalyst fine particles by polytetrafluoroethylene becomes insufficient. Therefore, the content of the photocatalyst fine particles is preferably 5 to 60%.

The photocatalyst fine particles include titanium oxide, strontium titanate, tungsten oxide, zinc oxide, tin oxide, cadmium sulfide and the like. Anatase type titanium oxide fine particles exhibiting the most excellent photocatalytic activity can be used. It is preferred to use. Further, in order to enhance the activity of the photocatalyst particles, an alkali metal ion can be supported.

As the above-mentioned supporting base material, a material having heat resistance which does not cause deformation or the like even when heated during firing is used, for example, metal foils such as aluminum and stainless steel, inorganic plates such as ceramic plates and glass plates, and the like. Heat-resistant plastic film such as polyimide or polytetrafluoroethylene, or woven glass fiber or polyamide fiber impregnated with heat-resistant plastic such as polytetrafluoroethylene, or felt of glass fiber, ceramic fiber, metal fiber, or carbon fiber alone or as a mixture A net-like material such as a glass fiber, a ceramic fiber, a metal fiber, and a carbon fiber alone or as a mixture can be used.

As the mesh-like or perforated support substrate in the case of the above-mentioned air-permeable photocatalyst sheet, any suitable substrate can be used as long as it satisfies requirements such as flexibility, heat resistance and high strength. , Aluminum wire mesh), punching sheets of heat-resistant plastic sheets (for example, polyimide and polytetrafluoroethylene), and woven fabrics of heat-resistant organic fibers (for example, glass fibers and polyamide fibers).

The dispersion may be applied to the support substrate by a method of applying a roll coater, a method of dipping the support substrate into the dispersion and pulling it up, and a method of spraying the dispersion. A method of brushing the dispersion, a method of casting the dispersion, and the like can be used. The concentration of the dispersion is set according to the coating method, and is usually 40% to 60%. An additive for increasing the porosity of the fired layer, an additive for improving the strength, and a gas adsorbent that can withstand the firing temperature can be appropriately added to the dispersion.

The above-mentioned photocatalyst sheet may be laminated with a deodorizing sheet containing one or more of activated carbon, zeolite and copper carboxymethyl cellulose as main components.

It is also possible to add at least one of activated carbon particles, zeolite particles and silica gel particles together with the photocatalyst particles.

FIG. 3A shows an example of an air purification unit according to the present invention, and FIG. 3B is a cross-sectional view taken along a line in FIG. 3A. In FIG. 3, reference numeral 2 denotes an ultraviolet ray generator, which is horizontally supported on a base plate 3. Reference numeral 1 denotes the above-described photocatalyst sheet, which is subjected to, for example, a bleaching process in order to increase the surface area, and is mounted on a base plate 3 with an ultraviolet generator 2 interposed therebetween.

The UV generator 2 has a wavelength of 400 nm.
A black light bull-lamp that generates the following ultraviolet light,
Fluorescent lamps, halogen lamps, xenon flash lamps,
Mercury lamps, germicidal lamps and the like can be used. The processing for increasing the surface area of the photocatalyst sheet 1 includes the above-described bridge.
Honeycomb processing and the like can also be used in addition to punch processing.

The photocatalyst sheet 1 may be disposed in the vicinity of the ultraviolet ray generator so as to efficiently irradiate the ultraviolet ray. The photocatalyst sheet 1 is shown in FIG. 4 (a) [plan view] and FIG. As shown in FIG. 4 (a), a UV lamp 2 is erected on a base plate 3 and a photocatalyst sheet subjected to a pleating process.
The table 1 can be placed on the base plate 3 so as to surround the ultraviolet lamp 2. If necessary, a reflecting mirror can be attached.

In the photocatalyst sheet of the air purifying unit according to the present invention, there is a gap between the photocatalyst fine particles and the resin binder. The deodorizing component in the air is efficiently oxidized and deodorized by the activated photocatalyst fine particles while passing over a large area in contact with the surface. Further, since the polytetrafluoroethylene carrying the photocatalyst fine particles is hardly decomposable, the resin binder can be stably retained for a long time without collapse, and the photocatalyst fine particles are wrapped through the voids of the resin layer. In addition, photocatalyst fine particles can be stably supported over a long period of time. Therefore, the deodorizing components in the air can be efficiently oxidized and deodorized over a long period of time.

FIGS. 5 (a) to 6 (d) show another example of the air purifying unit according to the present invention, in which the above-mentioned air-permeable photocatalyst sheet is provided in a light receiving area for the ultraviolet ray generator 2. FIG. 1 is cylindrical, elliptical, arc, spiral, umbrella, blow
Bend, wave, spiral, etc.
The filter can be housed in a case having a filter at the air inlet and a fan at the air outlet.

The air purifying unit shown in FIG. 5 (A) uses the air permeable photocatalyst sheet
It is bent into a double column concentric with the photocatalyst sheet and the distance between the photocatalyst sheet and the lamp is kept constant to achieve uniform irradiation. It is suitable for miniaturization and is surrounded by a cylindrical reflector (for example, made of aluminum plate). By doing so, the outer surface side of the photocatalyst sheet 1 can also be used for air purification. The flow direction of the air can correspond to either a parallel direction or a perpendicular direction to the ultraviolet irradiation lamp.

In the air purifying unit shown in FIG. 5B, the air-permeable photocatalyst sheet 1 is an elliptic cylinder having a U-shaped ultraviolet irradiation lamp or two ultraviolet irradiation lamps 2 as focal points. It is suitable for miniaturization like the one shown in FIG. 5 (a), and the outer surface of the photocatalyst sheet 1 is also air-purified by being surrounded by a cylindrical reflecting mirror (for example, made of aluminum plate). The direction of air flow can be either parallel or perpendicular to the ultraviolet irradiation lamp. In particular, in the case of a U-shaped ultraviolet irradiation lamp, since the lamp is fixedly supported at one end, it is easy to replace the photocatalyst sheet and to attach and detach it during cleaning.

In the air purifying unit shown in FIG. 5C, the above air-permeable photocatalyst sheet 1 is provided with a large and small semi-circular
In this configuration, the ultraviolet irradiation lamp 2 disposed on the reflection plate 31 is covered with the dome.

In the air purifying unit shown in FIG. 5D, the air permeable photocatalyst sheet 1
5 is spirally bent, and a single air-permeable photocatalyst sheet can exhibit performance close to that of the air purification unit shown in FIG.

The air purifying unit shown in FIG. 6 (A) uses the air permeable photocatalyst sheet
It is configured to be bent into a multi-stage umbrella shape and attached, and air purification can be performed in multiple stages for air flow parallel to the lamp.

The air purifying unit shown in FIG. 6 (b) uses the above-described air permeable photocatalyst sheet
It has a configuration in which it is bent and arranged in the form of a beam, and is planar, and can be used in combination with sunlight. It is also possible to use a reflector in combination as in the embodiment of FIG.

The air purifying unit shown in FIG. 6 (c) has a configuration in which the above-mentioned air-permeable photocatalyst sheet is bent and arranged on an ultraviolet irradiation lamp. (B) of FIG.
As in the embodiment shown in FIG. 5, since it is planar, it can be used in combination with sunlight, and it is also possible to use a reflector in combination as in the embodiment shown in FIG.

The air purifying unit shown in FIG. 6 (d) uses the air permeable photocatalyst sheet
It is configured to be spirally bent and attached, so that air can be purified in multiple stages for air flow parallel to the ramp.

The air purifying unit according to the present invention can be used for odors such as tobacco odors in living spaces (for example, toilets) and workplaces, harmful gases such as nitrogen oxides and sulfur oxides, and volatile organic compounds in new houses and the like. It is suitably used for reducing or removing the concentration of the compound (VOC) or for antibacterial purposes.

According to the air purifying unit shown in FIGS. 5 and 6, in addition to the excellent air purifying efficiency based on the chain void structure of the photocatalyst layer, the air purifying sheet has a multi-layer structure formed by bending the photocatalytic sheet. The air can be brought into contact with the photocatalyst multiple times, the air can be agitated when passing through the mesh of the gas permeable photocatalyst sheet, and the air passing through the back side of the gas permeable photocatalyst sheet is reflected by the reflection mirror. High efficiency because the back surface of the photocatalyst sheet can be excited and purified, and the air flow direction can be set in any of two directions, so that the degree of freedom in the arrangement direction of the ultraviolet irradiation lamp can be increased. In addition to the simple processing of bending the air-permeable photocatalyst sheet, it is possible to provide a small and low-cost air purification means.

[0037]

[Example 1] Polytetrafluoroethylene powder (particle diameter: 0.3 µm, specific gravity: 2.0 μm) containing 40% by weight of photocatalytic titanium oxide fine particles (particle diameter: 7 nm, specific gravity: 3.84) was used in the dispersion. The aqueous dispersion of 20) was used, and an aluminum foil having a thickness of 60 μm was used as the supporting substrate. This aluminum foil is immersed in a dispersion, pulled up, dried at 100 ° C., and fired at 390 ° C. × 2 minutes to form a sheet having a photocatalytic layer having a porosity of 12.2% and a thickness of 7 μm. A photocatalyst sheet was obtained. This sheet-shaped photocatalyst sheet was cut into 10 cm × 100 cm, and 10 cm × 10 cm.
A photocatalyst sheet was formed by processing into a belt having the outer dimensions of (1).
Two photocatalyst sheets were arranged with a 4 w, 11.5 cm long black blue light sandwiched therebetween, and the distance between each photocatalyst sheet and the black blue light was 3 cm to produce an air purification unit. When this air purification unit was installed in eight ordinary household toilets (floor area is about 0.9m x 1.8m) where the odor is constantly sensed, air purification was performed. There were six places where the bad odor disappeared, and two places where the constant odor disappeared two days after installation.

Example 2 A supporting base material having a thickness of 0.6 mm
Other than using a carbon fiber felt having a basis weight of 30 g / m ² ,
A sheet-like photocatalyst sheet was obtained in the same manner as in Example 1. Copper carboxymethyl cellulose was added to the sheet-like photocatalyst sheet.
Deodorizing sheet (Clean Sky manufactured by Kojin Co., Ltd.) is cut and cut into 10 cm x 100 cm.
A photocatalyst sheet was formed by processing into a beam having an outer dimension of 10 cm × 10 cm and hooks attached to both ends. Using this photocatalyst sheet, an air purifying unit was manufactured in the same manner as in Example 1, and this was placed in a chemical storage (floor area: about 0.9 mx 1.8 m) where the odor was constantly sensed. When the device was installed and air purification was performed, a constant odor was eliminated after 5 hours from the installation.

Comparative Example 1 In comparison with Example 1, polytetrafluoroethylene in a water dispersion was prepared by melting perfluoroalkylvinyl ether having a melt viscosity of 10 ⁴ poise.
Example 1 was the same as Example 1 except that the copolymer was replaced with a tetrafluoroethylene copolymer. The porosity of the photocatalyst layer was 1%.
When an attempt was made to deodorize the toilet in the same manner as in Example 1, satisfactory deodorization was not performed.

Example 3 A sheet-like photocatalyst sheet having a porosity of the photocatalyst layer of 3.1% and a thickness of 7 μm in comparison with Example 1.
A photocatalyst sheet was produced in the same manner as in Example 1 except for the above. When the deodorization of the toilet was attempted in the same manner as in Example 1, the deodorization efficiency was lower than that of Example 1, but Comparative Example 1
The results were more satisfactory.

As described above, Comparative Example 1 was inferior in deodorizing performance as compared with Examples 1 to 3 because of perfluoroalkyl vinyl ether.
The ter-tetrafluoroethylene copolymer is well heated and fused to the photocatalyst fine particles, and most of the surface of the photocatalyst fine particles is
It is covered with a fluoroalkyl vinyl ether-tetrafluoroethylene copolymer, and the melt viscosity of the perfluoroalkyl vinyl ether-tetrafluoroethylene copolymer is low, so that it is difficult to maintain the powder form at the time of sintering. It is presumed that gaps are unlikely to remain between them.

Example 4 A plain woven glass cloth (porosity: about 30%) having a yarn thickness of 0.5 mm and a mesh size of 2.5 mm × 2.5 mm was used as a mesh-like supporting base material. After the material was immersed in the same dispersion as used in Example 1, water was removed at 110 ° C. for 60 seconds, and then fired at 370 ° C. for 100 seconds to form a photocatalyst layer. -Obtained. The thickness of the breathable photocatalyst sheet is 0.55 mm, and the adhesion amount of titanium oxide fine particles is 9
It was 0 g / m ² .

Comparative Example 2 Comparative Example 2 was the same as Comparative Example 1 except that polytetrafluoroethylene in the dispersion was replaced with a perfluoroalkylvinyl ether-tetrafluoroethylene copolymer. did.

For each of the products of Examples and Comparative Examples, a 10 W black light and a gas permeable photocatalyst sheet cut into a sample area of 200 mm × 300 mm and formed into an arc shape in a closed container having an internal volume of 2 m ³ were prepared. Was set at a distance of 10 cm, acetaldehyde was injected into the container so as to have a concentration of 10 ppm, and a test was performed in which the aldehyde concentration after black light was turned on was measured by gas chromatography (on the sheet). UV intensity of 1m
W / cm ² ), the aldehyde concentration after 180 minutes was 3 ppm in Example 4, but was about 3 times higher in Comparative Example 2 than in Example 4.

[0045]

In the air purifying unit according to the present invention, a fine gap exists between the photocatalyst fine particles and the binder resin, and external air comes into contact with almost the entire surface of the photocatalytic fine particles through the gap. Since the photocatalyst sheet is used, the efficiency of oxidative deodorization of the active photocatalyst fine particles can be improved. Further, since the photocatalyst fine particles in the photocatalyst sheet are held in the resin binder and the resin itself is hardly decomposable, stable loading of the photocatalyst fine particles can be guaranteed. Therefore, it is possible to deodorize with high efficiency over a long period.

In particular, in the air purifying unit according to the third aspect, the passing air can be brought into contact with the photocatalyst multiple times in a multi-layered structure by bending the air permeable photocatalyst sheet, and the air is supplied to the air permeable photocatalyst sheet. It can be stirred when passing through the mesh, and the air passing on the back side of the air permeable photocatalyst sheet is reflected by a reflection mirror.
Can be purified by exciting its back side with reflected ultraviolet light by
Thus, the air purification efficiency can be further increased, and the size and cost of the air purification device can be reduced.

[Brief description of the drawings]

FIG. 1 is a drawing showing a photocatalyst sheet used in the present invention.

FIG. 2 is a view showing a gas permeable photocatalyst sheet used in the present invention.

FIG. 3 is a drawing showing an example of an air purification unit according to the present invention.

FIG. 4 is a drawing showing another example of the air purification unit according to the present invention.

FIG. 5 is a drawing showing another example of the air purification unit according to the present invention, which is different from the above.

FIG. 6 is a drawing showing another example of the air purification unit according to the present invention, which is different from the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Support base material 12 Photocatalyst layer 1 Photocatalyst sheet 2 UV generator

Claims (4)

[Claims] 1. A photocatalyst sheet having a photocatalyst layer on a supporting base material in which fine particles of photocatalyst are dispersed in a baked layer of polytetrafluoroethylene resin and fine voids are formed between the resin and the fine particles of photocatalyst generates ultraviolet light. An air purifying unit, which is disposed in a light receiving region for a device. 2. A photocatalyst sheet and activated carbon having a photocatalyst layer having a photocatalyst layer in which a fine void is formed between the resin and the photocatalyst fine particles, wherein the photocatalyst fine particles are dispersed in a fired layer of polytetrafluoroethylene resin. Characterized in that a laminate with zeolite or a deodorizing sheet containing one or more of copper carboxymethyl cellulose as a main component is disposed in a light receiving region for an ultraviolet ray generator for air purification. unit. 3. A gas permeable layer having a photocatalyst layer in which fine particles of photocatalyst are dispersed in a fired layer of polytetrafluoroethylene resin and fine voids are formed between the resin and the photocatalyst fine particles on a mesh-like or perforated support substrate. An air purification unit, characterized in that a photocatalyst sheet is disposed in a light receiving region for an ultraviolet ray generator by bending. 4. The air purification unit according to claim 1, wherein the porosity of the photocatalyst layer is 7% or more.