Photocatalytic sheet material

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to sheet materials such as knitted fabrics, woven fabrics, and non-woven fabrics, which decompose harmful organic compounds in gases and liquids by a photocatalytic function of metal oxides to detoxify or sterilize them.

【0002】

[Conventional technology]

Most metal oxides such as titanium oxide (TiO2) are so-called optical semiconductors that are excited by ultraviolet rays and have relatively free electron transfer on the surface. Photosemiconductors exhibit a photocatalytic function of redoxing substances in contact with the semiconductor surface with electrons freed by excitation.

【0003】

In everyday life, the photocatalytic function is used to obtain deodorizing and bactericidal effects. For example, air in a living room in a house, a hotel, a public facility, or a hospital, which is a facility used by an unspecified number of people. As a method of purifying the air, a photocatalytic function is added to the interior material, ceiling, and wall covering material, and when a photocatalytic semiconductor is supported on a curtain material that easily receives ultraviolet rays from sunlight, the indoor air is warmed by the sun and circulates upward. However, when they come into contact with these sheet materials, the odor floating in the living room and the volatile organic compounds (VOC) of the adhesive contained in the interior base material are efficiently removed.

【0004】

In addition to woven fabrics such as interior materials and curtain materials, filters for various devices, medical gauze, wet tissues, and non-woven fabrics such as artificial leather are also multi-surface bodies with many gaps between fibers. It is effective for hygiene, medical treatment, and deodorization to give the fabric a photocatalytic function.

【0005】

For this purpose, it is a condition that the fiber or cloth itself, which is the substrate supporting the photocatalytic semiconductor, is not decomposed by the photocatalytic function. However, the photocatalytic function is originally to excite the photocatalytic semiconductor by irradiation with ultraviolet rays and decompose the organic polymer compound by its oxidation and reduction actions. Therefore, the base material supporting the photocatalyst semiconductor is a metal fiber or a glass fiber. In the case of inorganic substances such as, there is no particular problem, but in the case of fibers of organic polymer compounds such as natural fibers and synthetic resin fibers, the base material itself is decomposed and deteriorates over time. (Photocatalytic deterioration) occurs. In addition, organic polymer compounds are also decomposed and deteriorated by ultraviolet rays (photochemical deterioration). Ultraviolet rays from the outside with respect to the substrate on which the photocatalytic semiconductor is supported on the surface are mostly absorbed by the layer of the photocatalytic semiconductor on the surface, but the remaining portion reaches the substrate.

【0006】

Looking at the conventional sheet material having a photocatalytic function, Japanese Patent Application Laid-Open No. 7-299354 proposes a sheet material in which white pigment particles having photocatalytic semiconductor particles supported on the surface are encapsulated or enclosed in a breathable sheet. However, it lacks versatility due to its special structure, and it is not possible to make soft materials such as gauze.

【0007】

Japanese Unexamined Patent Publication No. 7-316342 proposes a sheet material in which a synthetic resin containing particles of a photocatalytic semiconductor is formed into a sheet and used as a wall covering material, a flooring material, and various bags. If it is kneaded in the substrate as described above, the photocatalytic function cannot be fully exhibited. In addition, it cannot be applied to natural fiber cloths that cannot be kneaded.

【0008】

Japanese Unexamined Patent Publication No. 8-1010 discloses a sticking sheet having an oxide semiconductor fine particle layer on the front surface, an adhesive layer in the middle, and a release layer on the back surface. This sheet material is intended to be used in places where it is difficult to fix photocatalytic semiconductor particles such as walls and ceilings, and cannot be applied to soft materials such as gauze. Furthermore, looking at conventional sheet materials of this type, there is no disclosure about prevention or suppression of photocatalytic deterioration and photochemical deterioration. In addition, there is no disclosure about the possibility of cleaning and reusing the sheet and the use in an environment where sufficient ultraviolet rays cannot be obtained, such as at night or in a dark room.

【0009】

[Problems to be Solved by the Invention]

According to the present invention, a substrate made of an organic polymer compound carrying a photocatalytic semiconductor is not decomposed by the photocatalytic function and can withstand long-term use, the photocatalytic function is not lost even if it is washed if necessary, and it is sufficient from the outside. An object of the present invention is to provide a photocatalytic sheet material that can be expected to have a photocatalytic function even in an environment where a large amount of ultraviolet rays cannot be obtained.

【0010】

[Means for solving problems]

When a layer of photocatalytic semiconductor particles is formed on a sheet material to provide a photocatalytic function, a substrate protective layer that blocks the photocatalytic action on the surface of a substrate (carrier) that supports the photocatalytic semiconductor and is made of an organic polymer compound. To form. The sheet material is knitted fabric, woven fabric, non-woven fabric, film, and the material is synthetic resin fiber (including filament) such as linen, cotton, natural fiber of wool, polyester, rayon, nylon, polypropylene, vinyl, acetate, acrylic. ) Or a film of these synthetic resins. With the exception of film, these sheet materials have fiber, spinning, plying or ribbon stages.

【0011】

As the fiber, metal or glass fiber may be used, and one sheet material may be made by using a plurality of materials. Further, paper and synthetic leather can be used depending on the application. As the sheet material, those for interior and clothing are required to have design elements and toughness, and those for clothing and hygiene products are required to be flexible.

【0012】

The substrate protective layer is a layer of non-crystalline (amorphous) titanium oxide particles formed by using titanium peroxide, peroxotitanic acid, peroxotitanic acid containing a metal oxide other than titanium, and the like, and is inert with respect to the photocatalytic function. It is formed by a layer of titanium oxide particles. Since these do not have a photocatalytic function, they do not decompose the substrate.

【0013】

The layer of amorphous titanium oxide particles can be formed on the surface of the substrate by, for example, the following method. The base cloth is dyed as the final step, and then sprayed with an aqueous solution of titanium peroxide that shows the properties during the process of changing the state from the sol state to the gel state, or after dipping in this aqueous solution, extra The aqueous solution of the above solution is removed, dried, and then fixed at a temperature of 200 ° C. or less in consideration of the heat resistant temperature of the substrate.

【0014】

Alternatively, the surface of the substrate is coated with an aqueous solution of peroxotitanic acid by dipping or the like in the same manner as described above, dried, and then fixed at a temperature of 200 ° C. or lower. As a result, a layer of amorphous titanium peroxide particles is formed on the surface of the substrate. At this time, when the temperature becomes 200 ° C. or higher, in the case of peroxotitanic acid, the amorphous titanium peroxide particles have characteristics similar to those of anatase-type titanium oxide and exhibit a photocatalytic function.

【0015】

As another method, the raw material resin of the fiber constituting the substrate is released from the nozzle into the peroxotitanic acid aqueous solution to form a thin film of amorphous titanium peroxide particles on the surface of the fiber. Also in this case, after drying, it is fixed at a temperature of 200 ° C or less. The fixing time may be after spinning, twisting, or weaving.

【0016】

The layer of titanium oxide inactivated with respect to the photocatalytic function can be formed on the surface of the substrate by, for example, the following method. An ionic surfactant is mixed in anatase-type titanium oxide sol at 1 wt% or more with respect to the concentration of titanium oxide (TiO2) in the sol to inactivate the photocatalytic function of titanium oxide, and this sol is sprayed, dipping or coated on a substrate. .. Then, after drying, it is heated and fixed.

【0017】

When a layer of a photocatalytic semiconductor is formed on the surface of a substrate subjected to this processing, even if the photocatalyst semiconductor is excited by irradiation with ultraviolet rays, the electrons moving to the surface side of the substrate are ions of the ion-type surface active material contained in the substrate protective layer. It is not possible to perform a redox action on the surface of the substrate by binding to. Therefore, the photocatalytic function does not act on the substrate, and the substrate can be protected.

【0018】

The substrate on which the photocatalytic semiconductor is supported is not limited to a knitted fabric, a woven fabric, a non-woven fabric, or a sheet, but may be a fiber, a spin, a twisted yarn, or a ribbon at each stage leading to the sheet. If there is no processing difficulty, if the particles of the photocatalytic semiconductor are supported at the fiber or thread stage, the photocatalytic semiconductor will be strongly fixed when it becomes a sheet material, and the photocatalyst function will be exhibited even if cleaning is repeated several times. Maintained. That is, as a substrate on which a photocatalytic semiconductor is supported in order to give the sheet material a photocatalytic function, one or several of fibers, filaments, threads, ribbons, knitted fabrics, woven fabrics, non-woven fabrics or films can be used depending on the purpose. Can be selected.

【0019】

Furthermore, since it is natural fibers and synthetic resin fibers that need to form a layer of non-crystalline titanium oxide particles, a layer of titanium peroxide, or a layer of inactivated titanium oxide, for example, glass is used with a filter or the like. When the inorganic fiber and the organic fiber cannot be treated separately, such as a non-woven fabric in which the fiber and the synthetic resin fiber are entwined, the fiber is treated as a substrate, that is, a treatment for forming a substrate protective layer is performed at the fiber stage. Then, it is rational to weave the fiber into a non-woven fabric. However, it may be woven into a non-woven fabric to form a substrate protective layer as a whole.

【0020】

Photocatalytic semiconductors include TiO2, ZnO, SrTiO3, CdS, CdO, CaP, InP, In2 O3, CaAs, BaTiO3, K2 NbO3, Fe2 O3, Ta2 O5, WO3, SaO2, Bi2 O3, NiO, Cu2 O, SiC, SiO2. , MoS2, MoS3, InPb, RuO2, CeO2. The ultraviolet rays absorbed by these photocatalytic semiconductors have a wavelength of 50 to 400 nm, which is slightly shorter than that of visible light, but some photocatalytic semiconductors have an absorption wavelength in the visible light region. For example, SiC is 413 nm, CdS is 496 nm, and Fe2 O3 is 539 nm.

【0021】

Since the wavelength of the light beam that excites the photocatalytic semiconductor differs depending on the type, it is possible to select an appropriate one according to the emission spectrum characteristics and application of the ultraviolet source, or to adjust by combining multiple types of photocatalytic semiconductors. it can. Further, by adding an inorganic pigment or a metal to adjust the composition or adjusting the heat treatment in the manufacturing process, the wavelength (absorption band) of ultraviolet rays required for exerting the photocatalytic function can be changed. For example, when a small amount of CrO3 is added to TiO2, the absorption band shifts to the long wavelength side. In addition, Pt, Ag, Rh, RuO2, Nb, Cu, Sn, NiO, etc. may be used as additives to complement the functions such as fungicide and sterilization.

【0022】

Among the above photocatalytic semiconductors, TiO2 (titanium oxide) is commercially available, is harmless to the human body, is inexpensive, and is easy to use. "ST-01" (trade name Ishihara Sangyo Co., Ltd.) is provided as a powder, and "TO sol" (trade name Tanaka Transfer Co., Ltd.) and "STS-01" (trade name Ishihara Sangyo Co., Ltd.) are provided in a sol state. Has been done. The particle size of TiO2, which constitutes powders and sol, is very fine at 7 to 20 nm.

【0023】

Various means such as spraying, coating, dipping, and sputtering can be adopted for fixing the photocatalytic semiconductor to the substrate, and the selection is made according to the type of the substrate. Apply processing. In the case of TiO2, the fixing temperature is 50 ° C to 500 ° C, which is relatively wide, but when peroxotitanic acid is used as the substrate protective layer, the temperature is 200 ° C or less. In addition, the heat-resistant temperature of the fibers currently on the market is 260 ° C or less for rayon, 200 ° C or less for acetate, 180 ° C or less for nylon, and 230 ° C or less for polyester, and it can sufficiently withstand heat processing coating. be able to.

【0024】

In the photocatalyst sheet material formed in this way, the photocatalyst semiconductor carried by receiving the ultraviolet rays of fluorescent lamps and sunlight in the room is excited, and harmful organic substances are decomposed by oxidation and reduction actions to deodorize. Demonstrates effects such as air purification and sterilization. In particular, when it is used for a curtain that is installed in an opening and easily receives sunlight, the photocatalytic semiconductor is heated and efficiently contacts the indoor air that circulates ascending, and the odor in the living room and volatile components contained in building materials and adhesives are contained. Removes volatile organic compounds (VOCs). In addition, when used in medical products such as sterilizing gauze and sanitary products such as wet wipes, it is effective in preventing infectious diseases.

【0025】

The substrate may carry an ultraviolet radiator. The photocatalyst sheet material in which an ultraviolet radiator is mixed in the substrate self-supplies the ultraviolet rays required for excitation of the photocatalytic semiconductor, so that the photocatalyst function can be obtained even when there is no or slight amount of ultraviolet rays supplied from the outside such as at night or indoors. Can be exerted and maintained.

【0026】

There are two types of ultraviolet radiators, spontaneous type and phosphorescent type.Spontaneous ultraviolet emitters (spontaneous luminescent ceramics) are substances that consume internal energy and emit light by themselves, and utilize the radiative decay of radium and promethium. It has an ultraviolet region in the emission spectrum. At present, crushed fine particles obtained by re-crushing a solidified rock refined powder containing such a component are used. The particle size is 20 to 50 μm.

【0027】

A phosphorescent ultraviolet radiator (phosphorescent luminescent ceramic) is a substance that takes in and stores external energy and emits light while emitting that amount, and also has an ultraviolet region in the emission spectrum. Commercially available products include "Luminova" (trade name: Root Special Chemistry) and "Kiplus" (trade name: Next Eye Co., Ltd.). These are mainly composed of strontium aluminate (SrAl2 O4) containing components such as high-purity alumina, strontium carbonate, europium, and dysprosium.

【0028】

When the phosphorescent ultraviolet radiator is placed under sufficiently strong external ultraviolet rays for 4 to 30 minutes, the absorption of external energy for light emission is saturated, and after that, even if the external energy is cut off, it continues to emit light for about 1000 minutes. , Supply ultraviolet rays to the photocatalytic semiconductor. Taking "luminova" as an example, the wavelength peak of the emitted ultraviolet rays is around 440 to 530 nm, but it also has a wavelength region for exciting a normal photocatalytic semiconductor.

【0029】

It should be noted that some of these ultraviolet radiators have a large decrease in performance when they absorb moisture. Therefore, if the substrate is transparent with respect to ultraviolet rays so as not to come into direct contact with moisture, ultraviolet radiation is emitted into the substrate. It is desirable to mix the body. In the case of natural fibers, they are coated before the formation of the substrate protective layer by spraying a synthetic resin mixed with an ultraviolet radiator.

【0030】

The form in which the ultraviolet radiator is supported on the sheet material is mainly adhesion and fixation to the surface of the substrate, but in the case of a synthetic resin fiber or a synthetic resin film, it can be mixed in the substrate. When the fiber is a synthetic resin filament, the cross section is partitioned radially and an ultraviolet radiator is mixed in a part of the sections, or the outermost layer of the cross section is formed into a ring shape and the layer is mixed with the ultraviolet radiator. Sometimes. In such a filament, a resin raw material mixed with an ultraviolet radiator and a resin raw material not mixed with an ultraviolet radiator are extruded from different nozzles into air or a cooling solution such as an organic solvent or water and cured. Manufactured in close contact with each other before. Further, in the case of natural fiber, since the particles of the ultraviolet radiator cannot be mixed with the natural fiber itself, it is twisted with the synthetic resin fiber mixed with the ultraviolet radiator at the stage of plying.

【0031】

As described above, the substrate undergoes photocatalytic deterioration due to the photocatalytic function of the photocatalytic semiconductor and photochemical deterioration due to ultraviolet rays. The suppression of photocatalytic deterioration has already been described. In order to suppress photochemical deterioration, it is utilized that the rate of photochemical deterioration and the wavelength at which the photochemical deterioration is most likely to occur differ depending on the resin. By the way, the maximum deterioration wavelength of a typical synthetic resin is 318 nm for polyester, 300 nm for polypropylene, 285 to 305 nm / 330 to 360 nm for polycarbonate, and 300 nm for polyethylene. That is, in order to prevent photochemical deterioration, an ultraviolet radiator is selected to make its emission spectrum different from the maximum deterioration wavelength of the resin. In addition, the excitation wavelength of the photocatalytic semiconductor supported by the substrate and the maximum deterioration wavelength of the synthetic resin should not match. Of course, adding an ultraviolet absorber such as ubitroxibenzophenone or triazole to the substrate is effective in preventing photochemical deterioration.

【0032】

BEST MODE FOR CARRYING OUT THE INVENTION

First example Using a non-woven fabric [Shinwa Co., Ltd. 4880C] in which polyester fibers and rayon fibers are bonded with an acrylic binder as a base material, it was first washed with tap water, then washed with pure water, and dried at 70 ° C. .. Then, it is dipped in titanium peroxide sol (TiO3 0.3wt% PH 5 viscous) at room temperature (23.8 ° C) to remove excess sol agent, and then titanium oxide powder [ST-01 Ishihara Sangyo (ST-01 Ishihara Sangyo (ST-01 Ishihara Sangyo)) before drying. Co., Ltd.] was placed in a floating space, and titanium oxide particles were attached to the entire surface.

【0033】

The product in this state was semi-dried in an atmosphere of 50 ° C, ironed on the entire surface at 120 to 150 ° C, and the titanium oxide particles were fixed to obtain a finished product. The finished product looks slightly yellowish and whitish as a whole, and although slight clogging is observed in the gaps between the fibers constituting the non-woven fabric, the appearance impression is almost the same as that before processing. When a schematic representation of an enlarged fiber cross section is shown, as shown in FIG. 1, a substrate protective layer 2 composed of a layer of amorphous titanium peroxide particles is formed on the surface of the fiber 1 located at the center. Further, a layer of a photocatalytic semiconductor is formed on the surface thereof.

【0034】

After leaving the finished product in a normal living room for two months with an arrangement equivalent to wallpaper, I saw it pulled vertically and horizontally and bent, but there were no abnormalities in strength or other factors. This experiment is still ongoing, and long-term deterioration of the substrate (photocatalytic deterioration, photochemical deterioration) is observed. The redox function will be described later as an experimental example.

【0035】

Second example Based on a woven fabric made of a blended fiber of 50% cotton and 50% polyester [Deolia Co., Ltd. Nippon Fisba], as in the first example, first wash with tap water, then wash with pure water, and then 70 Dry at ° C. Then, it is dipped in titanium peroxide sol (TiO3 0.5wt% PH 6.4 sol) at room temperature (23.8 ° C) to remove excess sol, and then titanium oxide powder [ST-01 Ishihara Sangyo Co., Ltd.] before drying. )] Was placed in a floating space, and titanium oxide particles were attached to the entire surface of the woven fabric.

【0036】

The product in this state was semi-dried in an atmosphere of 50 ° C, ironed on the entire surface at 120 to 150 ° C, and the titanium oxide particles were fixed to obtain a finished product. The schematic diagram of the fiber cross section is the same as that in FIG. The finished product looks a little yellowish as a whole, but the appearance is almost the same as before processing. After leaving the finished product in a normal living room for two months with an arrangement equivalent to wallpaper, I saw it pulled vertically and horizontally and bent, but there were no abnormalities in strength or other factors. This experiment is still ongoing, and long-term deterioration of the substrate (photocatalytic deterioration, photochemical deterioration) is observed. The redox function will be described later as an experimental example.

【0037】

Third example Using a 100% cotton woven fabric [Dufy Co., Ltd. Nippon Fisba] as a base material, it was first washed with tap water, then washed purely and dried at 70 ° C. Then, at room temperature (23.8 ° C), dip the titanium oxide sol (TiO3 1.76wt% PH 6.0 sol) with the titanium oxide sol [TO Tanaka Transfer 3.94wt% PH 8.1] into a sol agent, and add excess. After removing the sol agent, it was dried in an atmosphere of 50 ° C.

【0038】

This product forms a layer in which titanium peroxide particles and titanium oxide particles are mixed on the surface layer of the fiber, but since the titanium peroxide sol has better spreadability with respect to the fiber surface, the titanium peroxide particles are near the surface of the fiber. There is a layer of titanium oxide on the surface layer side. The photocatalytic function will be slightly inferior, but it is not necessary to further attach titanium oxide powder. Then, the entire surface was ironed at 120 to 150 ° C., and the layers of titanium oxide particles and titanium peroxide particles were fixed to obtain a finished product.

【0039】

The appearance of the finished product is almost the same as before processing. After leaving the finished product in a normal living room for two months with an arrangement equivalent to wallpaper, I saw it pulled vertically and horizontally and bent, but there were no abnormalities in strength or other factors. This experiment is still ongoing, and long-term deterioration of the substrate (photocatalytic deterioration, photochemical deterioration) is observed. The redox function will be described later as an experimental example.

【0040】

2 to 4 are examples in which the polyester fiber 1 is mixed with the phosphorescent ultraviolet radiator "Luminova" in the above example. In the case of FIG. 2, the entire fiber 1 is mixed, and in the case of FIG. 3, the fiber is shown. In the example of FIG. 4, it is mixed in the ring portion on the surface layer side in the cross section in a plurality of regions in which the cross section is divided radially. The hatched portion is the mixing portion, and reference numeral 1 indicates a fiber, reference numeral 2 indicates a substrate protective layer, and reference numeral 3 indicates a layer of photocatalytic semiconductor particles. The peak of the light wavelength absorbed by the polyester fiber is 318 nm, and the peak of the light wavelength absorbed by the titanium oxide particle layer is adjusted to 480 nm. On the other hand, "Luminova" adjusts the band of the emitted light wavelength to 440 to 530 nm.

【0041】

FIG. 5 shows a cross section of a blend of natural fibers and synthetic resin fibers mixed with an ultraviolet radiator, which is one means for imparting phosphorescent performance to a woven fabric using natural fibers.

【0042】

Experimental example Prepared sheet material (10 x 10 cm for each) "Dufy" (100% cotton) woven fabric treated in the second example b. "Deolia" treated in the second example (50% cotton, 50% polyester) Woven fabric c. "4880C" (polyester rayon + acrylic) treated in the first example Lubinder) Non-woven fabric d. "7870" treated in the first example [Shinwa Co., Ltd. polyester] Non-woven e. "7330GP" processed in the first example [Shinwa Co., Ltd. Polyester Les Rayon] Non-woven fabric f. "7230CG] [Shinwa Co., Ltd. cotton] non-woven fabric treated in the first example [0043]

apparatus Small polypropylene container (with a 14 x 14 x 3 cm square housing) 6 Large float glass container (with a rectangular housing of 62 x 42 x 42 cm) , With float glass lid) 1 piece 2 black lights (20w) Colored water [Pollux Blue (PM-1) Sumitomo Color Co., Ltd.] PH5.5 ~ 6.5 Nonionic 0.04% solution Active ingredient 0.014% Required amount [0044]

procedure As shown in FIGS. 6 and 7, the large container 4 is placed on the desk, and the black light 5 is horizontally placed 70 mm from the upper surface of the desk directly above the large container 4. Six small containers 6 are evenly arranged inside the large container 4, and the prepared sheet material 7 is stored in each. Then, 50 cc of colored water was injected into each of the small containers 6. Then, the lid of the large container 4 was closed and left at room temperature, and the change in the color of the colored water in each small container was observed from the outside. Pollux blue is a pigment of an organic polymer compound, which is decomposed by the photocatalytic function of a photocatalytic semiconductor and loses the function of coloring a solution. From this, it is possible to know the degree of progress of the redox action by the photocatalytic function and the strength of the photocatalytic function.

【0045】

result<img file="JPH1016121A_D0001.tif" />【0046】

Second time The sheet materials a to f used in the first experiment were washed, and the experiment was repeated in the same manner. 50cc of Pollux Blue coloring liquid was newly injected into each small container.<img file="JPH1016121A_D0002.tif" />【0047】

Third time The sheet materials b, e, and f used in the second experiment were washed again, and 50 cc of Pollux blue coloring liquid was newly injected into each small container, and the experiment was repeated in the same manner. The number of small containers was 3 in the large container.<img file="JPH1016121A_D0003.tif" />【0048】

From the above, it can be seen that all the sheet materials exhibit a sufficient redox effect even if there is a difference in photocatalytic function (a, b> c, d> f> e).

【0049】

[Effect of the invention]

According to the configurations according to claims 1 and 2, a non-crystalline titanium peroxide particle layer or an inactivated titanium oxide particle layer is formed on the surface of the substrate, so that the substrate is a natural fiber or a synthetic resin fiber. Even if a layer of a photocatalytic semiconductor is formed on the surface of the organic polymer compound of the above, the substrate is not decomposed and does not deteriorate due to its own photocatalytic function. Therefore, it can be used as a photocatalyst sheet material for a long period of time.

【0050】

According to the configuration according to claim 3, since the sheet material itself is provided with an ultraviolet radiator, it can function as a photocatalyst sheet even in a dark place where ultraviolet rays do not reach. This performance is usually useful as a filter or medical sheet material used in places where ultraviolet rays are hard to reach. According to the configuration according to claim 4, the substrate of the organic polymer compound is not deteriorated by ultraviolet rays, and the durability of the photocatalyst sheet material is further improved.

[Simple explanation of drawings]

[Figure 1]

FIG. 6 is a cross-sectional view of a fiber having a substrate protective layer and a layer of a photocatalytic semiconductor.

[Figure 2]

A cross-sectional view of a fiber in which an ultraviolet radiator is mixed in a substrate and has a substrate protective layer and a layer of a photocatalytic semiconductor.

[Fig. 3]

FIG. 3 is a cross-sectional view of a fiber having a substrate protective layer and a photocatalytic semiconductor layer formed in a radial manner in a region of the substrate mixed with an ultraviolet radiator.

[Fig. 4]

FIG. 3 is a cross-sectional view of a fiber having a ring-shaped region of a substrate mixed with an ultraviolet radiator, and having a substrate protective layer and a photocatalytic semiconductor layer.

[Fig. 5]

FIG. 3 is a cross-sectional view of a twisted yarn in which a substrate protective layer and a photocatalytic semiconductor layer are formed by blending natural fibers and synthetic resin fibers mixed with an ultraviolet radiator.

[Fig. 6]

The front view of the experimental apparatus shown schematically.

[Fig. 7]

Top view of the experimental device schematically shown (black light omitted).

[Explanation of symbols]

1 Hypokeimenon 2 Hypokeimenon protective layer 3 Layer of photocatalytic semiconductor particles 4 large containers 5 black light 6 small container 7 Sheet material