Photocatalyst supporting glass fiber textile, manufacturing method of the same and air filter apparatus using the same

【0001】

[Technical field to which the invention belongs]

The present invention relates to a photocatalyst-supported glass fiber cloth, a method for producing the same, and an air filter device used for air cleaning of a clean room or a living space.

【0002】

[Conventional technology]

At present, a clean room is indispensable in a factory for manufacturing precision equipment such as semiconductors or electronic parts, and at least an air filter device is indispensable in a food, chemical or chemical factory. Alternatively, in recent years, high airtightness and high heat insulation have progressed in public facilities such as general houses and hospitals, and as a harmful effect, volatile organic compounds such as formaldehyde or semi-volatile organic compounds (hereinafter referred to as these) released from building materials are used. The problem of sick building syndrome (collectively referred to as "VOC, etc.") or the problem of residual odorous gas has arisen, and in order to solve these problems, the introduction of air filter devices in general living spaces is progressing. I'm out.

【0003】

So far, various methods for removing VOCs and odorous gases have been developed, and there are various air filter devices applying them. For example, Patent Document 1, Patent Document 2, Patent Document 3 or Patent Document 4 describes a filter in which a photocatalyst such as titanium oxide is fixed to the surface of glass fiber or its woven fabric by a sol-gel method or the like.

【0004】

Further, Patent Document 5 describes a filter in which a photocatalyst is fixed on the surface and inside of a porous glass film formed by a phase separation method (including acid treatment) or a sol-gel method. Similarly, Patent Document 6 describes a filter in which a photocatalyst is fixed to a glass film having a porous surface and inside for which the forming method is unknown.

【0005】

Further, in Patent Document 7, although it is not an air filter, γ-alumina, silica gel, glass, etc. are heated to about 1,000 ° C to separate the phases, and then treated with an alkali or an acid to make the surface porous. A wall material is described in which a photocatalyst is fixed on the surface of the wall material.

【0006】

[Patent Document 1]

Japanese Unexamined Patent Publication No. 12-176246 [Patent Document 2]

Japanese Unexamined Patent Publication No. 2000-199173 [Patent Document 3]

Japanese Unexamined Patent Publication No. 6-320010 [Patent Document 4]

Japanese Unexamined Patent Publication No. 8-309122 [Patent Document 5]

Japanese Unexamined Patent Publication No. 2000-317315 [Patent Document 6]

Japanese Unexamined Patent Publication No. 2001-239168 [Patent Document 7]

JP-A-2002-45650 [0007]

[Problems to be Solved by the Invention]

However, in the air filter device described in Patent Document 2, since the photocatalyst is only fixed to ordinary glass fiber having a smooth surface or its woven fabric, the area of the photocatalyst that can come into contact with VOC or the like is small, and its decomposition. The removal capacity was limited.

【0008】

Further, in the filters described in Patent Document 5 and Patent Document 6, since a film of porous glass is formed, some kind of base material supporting the film is indispensable, the number of manufacturing members increases, and the manufacturing process thereof is increased. There was a problem that became complicated. Moreover, because it is extremely difficult to form a uniform, porous glass film with a large external surface area, these filters are industrial large-scale air filter devices, even with favorable results at the laboratory level. Was not available to.

【0009】

Alternatively, in the wall material described in Patent Document 7, γ-alumina is mainly studied as a base material for supporting a photocatalyst. For example, when glass fibers are subjected to the same heat treatment as γ-alumina, the glass fibers are melted. Or, the average pore diameter of the porous layer formed on the surface thereof becomes too large, and there is a problem that the ability to decompose and remove by a photocatalyst is insufficient as described above. In addition, the wall material has insufficient strength against dynamic airflow, so it could not be used as an air filter.

【0010】

The present invention has been made by paying attention to the above problems. The purpose is to support a photocatalyst that has the strength to withstand the pressure loss that is indispensable as an air filter, can quickly adsorb a large amount of VOCs and odorous gases, and can efficiently decompose and remove the adsorbed substances. The purpose is to provide fiberglass cloth. Further, it is an object of the present invention to provide a method for easily and surely making at least the surface of the glass fiber constituting the glass fiber cloth porous, and an air filter device using the glass fiber cloth.

【0011】

[Means for solving problems]

In order to achieve the above object, the present invention is 100 to 400 m.²It is a photocatalyst-supported glass fiber cloth in which a photocatalyst is supported on the surface of a porous glass fiber cloth having a specific surface area of / g.

【0012】

As a result of diligent research on the adsorption capacity and decomposition / removal capacity of VOC and the like related to the air filter, the present inventors have made a porous glass fiber cloth, for example, a porous glass fiber woven cloth as a base material in order to secure the strength that can withstand the pressure loss. When a photocatalyst is supported on this and used, the specific surface area of the porous glass fiber woven fabric before the photocatalyst is supported is 100 to 400 m.²We found that VOCs and odorous gases were removed most efficiently at / g. The pores may be present only in the surface layer of the glass fiber constituting the glass fiber cloth, but may extend to the central layer of the glass fiber. This specific surface area value is based on the measurement by the nitrogen adsorption BET method on the porous glass fiber cloth before supporting the photocatalyst. The larger the specific surface area, the larger the capacity of physical adsorption or chemisorption due to capillarity. However, the specific surface area is 400m²If it exceeds / g, the strength of the glass fiber cloth will be insufficient and it will be difficult to handle it. On the other hand, 100m²If it is less than / g, the area of the photocatalyst that comes into contact with VOCs and odorous gas is too small, and it takes time to decompose and remove it. A more preferred range is 200-400m²/ g. By the way, the specific surface area is 300m²In the case of / g, per 1 g of the glass fiber cloth, 3.0 × 10 gas molecules with a diameter of 1.0 nm⁸Single molecule can be adsorbed in individual pores.

【0013】

Further, the average pore diameter (before supporting the photocatalyst) of the porous layer formed on the glass fiber cloth can represent a suitable range in which VOCs and the like are efficiently removed. That is, the preferable range is 1.0 to 30 nm. This average pore diameter is a value measured by the nitrogen adsorption Inkley method. When the average pore size exceeds 30 nm, the pore size is too large compared to molecules such as VOCs, and their adsorption becomes inefficient. On the other hand, if it is less than 1.0 nm, the photocatalyst does not penetrate well into the pores, the amount of photocatalyst supported per unit surface area of the glass fiber cloth is insufficient, and decomposition and removal of VOCs and the like becomes inefficient. A more preferable range is 1.0 to 20 nm.

【0014】

As the porous glass fiber cloth in the present invention, a woven cloth made of porous glass fiber or a non-woven fabric made of porous glass fiber is used. Hereinafter, a case where a woven fabric made of porous glass fiber is used will be described.

【0015】

The external surface area of the glass fiber woven fabric is 0.20 to 0.70 m.²/ g is preferable, and 0.35 to 0.63m²/ g is suitable. Here, the external surface area refers to a glass fiber woven fabric in the case where the glass fiber has at least a porous layer on the surface, but the surface of the glass fiber is smooth without the porous layer. The surface area per unit weight. Specifically, it is calculated by the following formula.

【0016】

External surface area = (total outer peripheral area of glass fiber per count / specific gravity of count) / (specific gravity after acid treatment / specific gravity before acid treatment) [0017]

Here, the "total outer peripheral area of the glass fiber per count" and the "count weight" are calculated from the standard of the glass fiber. On the other hand, "specific gravity after acid treatment" and "specific gravity before acid treatment" are measured by the following Archimedes method. A glass fiber woven fabric is hung on a balance with a thin platinum (Pt) wire and its weight is measured. Next, the glass fiber woven fabric is submerged in a beaker containing pure water while suspended from a balance, and the reduced weight (weight in air-weight in water) is measured. Then, the specific gravity of the glass fiber woven fabric is obtained from the following formula.

【0018】

Specific gravity = ((weight of glass fiber woven fabric / reduced weight in pure water) x density of pure water) + density of air x (1- (weight of glass fiber woven fabric / weight of pure water)) [0019]

Therefore, this external surface area is inversely proportional to the average diameter of the glass fibers. External surface area is 0.70m²If it exceeds / g, the glass fiber is too thin, so that the manufacturing cost of the glass fiber itself becomes remarkably high, and the strength thereof is remarkably lowered by the acid treatment described later. On the other hand, 0.20m²If it is less than / g, the glass fiber becomes too thick, and even if its strength is sufficient, the ability to decompose and remove VOCs is likely to be insufficient. For this reason, there arises a problem that the gas flow rate per unit time of the air filter device becomes too small. External surface area is 0.20 ~ 0.70m²The average diameter of / g glass fiber is about 5-9 μm. Two or more types of glass fibers having different fiber diameters may be mixed.

【0020】

As the glass fiber, one having an acid-soluble component in the composition is used. At least, a glass composition having an E-glass composition that easily forms a porous layer on the surface and can be obtained at low cost is preferable. Table 1 shows the general composition component content of this E glass composition.

【0021】

[table 1]

Ingredients Weight% SiO₂ 52 ~ 56Al₂O₃ 12 ~ 18CaO 16 ~ 25MgO 0 ~ 6B₂O₃ 5 ~ 13R₂O 0 ~ 3TiO₂ 0 ~ 0.4Fe₂O₃ 0.05 ~ 0.5F₂ 0 ~ 0.5 However, R₂O is Na₂O and K₂Shows the sum of either or both of O.

【0022】

For reference, Table 2 shows the composition component content of glass fibers consisting of five types of commercially available E glass compositions.

【0023】

[Table 2]<img file="JP2004002176A_D0001.tif" />However, R₂O is Na₂O and K₂Shows the sum of either or both of O.

【0024】

When glass fiber is subjected to acid treatment such as immersion in an acid solution, the acid-soluble component in the glass fiber, for example, B₂O₃, CaO, R₂O and the like gradually elute from the surface, and a porous layer is formed on the surface. When the woven fabric is processed into a woven fabric using a loom after the porous layer is formed, the glass fibers are not slippery and the yarn breaks frequently. Therefore, the acid treatment is preferably applied after the glass fiber is processed into a woven fabric.

【0025】

The weaving method of the glass fiber is preferably satin weave, twill weave, imitation weave, or the like, and plain weave is not preferable. This is because plain weave has a smaller external surface area than satin weave, twill weave, or misa weave, which makes the adsorption of VOCs and odorous gases inefficient. In addition, the basis weight of the glass fiber woven cloth is 100 to 1,000 g / m.²The thickness is preferably 0.1 to 1.0 mm. Even if the weave is satin weave, twill weave or imitation weave, the basis weight is 100 g / m.²If it is less than 0.1 mm and the thickness is less than 0.1 mm, a sufficient external surface area cannot be secured. On the other hand, the basis weight is 1,000 g / m.²If it exceeds 1.0 mm and the thickness exceeds 1.0 mm, it becomes difficult to process and handle it as an air filter. For example, in the case of a general household air filter, the gas flow rate is 10 m.³It is required that the pressure loss is 100 Pa or less and the removal rate is 95%. In order to meet this requirement, the external surface area of 600 m is made of glass fiber with an E glass composition of 5 to 9 μm.²If it is an air filter, the basis weight is 343g / m.²Must be.

【0026】

The method of the acid treatment is not particularly limited, but for example, a glass fiber woven fabric is immersed in an acid aqueous solution such as hydrochloric acid for a predetermined time, the temperature is raised or stirred as necessary, and then the cloth is washed with water and dried. A series of processes can be mentioned. Here, various conditions such as the concentration of the acid aqueous solution to be used, the temperature rise temperature, and the immersion time are appropriately determined depending on the type of acid, the required degree of acid treatment (specific surface area of the glass fiber after the acid treatment), and the like. For example, when an acid treatment is applied to a glass fiber woven fabric made of a glass fiber having an E glass composition having an average diameter of 9 μm in a red woven fabric, it is placed in an acid aqueous solution of 1.5 to 6.0 specified at 30 to 70 ° C. By immersing the glass fiber woven fabric for about 6 to 24 hours, the specific surface area is 100 to 400 m.²It can be surely increased to / g. When an acid aqueous solution of less than 1.5 specifications is used, it may take a long time to form a desired porous shape, or it may not be possible to make it porous. On the other hand, if an aqueous acid solution exceeding 6.0 is used, the corrosion by the acid is rapid, and it becomes difficult to adjust the porous shape with time. The same can be said for the temperature. If it is less than 30 ° C, it takes a long time to form the desired porous shape, while if it exceeds 70 ° C, the porous shape is adjusted by time. Becomes difficult.

【0027】

It is preferable that the glass fiber woven fabric is heat-treated before the acid treatment for the purpose of removing the sizing agent applied at the time of spinning or the lubricant applied at the time of processing the woven fabric. However, this heat treatment is for removing unnecessary deposits, phase-separates γ-alumina as described in Patent Document 7, and puts a component easily soluble in alkali or acid on the surface layer. It must not be moved. In the present invention, since the multi-component glass fibers shown in Table 1 above are used instead of γ-alumina, the average pore diameter in the porous layer of the glass fibers becomes too large when phase separation occurs. As a result, not only the glass fiber does not fall within the above-mentioned preferable range, but also the strength of the glass fiber is remarkably deteriorated. In order to remove unnecessary deposits without splitting the glass fibers, it is preferable to keep the heating temperature below 600 ° C.

【0028】

The case where the woven fabric of the porous glass fiber is used as the porous glass fiber cloth in the present invention has been described above, but the non-woven fabric of the porous glass fiber can also be used in the same manner. Further, as the porous glass fiber, for example, a porous silica fiber produced by a sol-gel method can be used in addition to the one obtained by the above acid treatment.

【0029】

Nonwoven fabric of glass fiber is mainly produced by a papermaking method, a dry lamination method or the like using so-called glass short fibers. The shape of the short glass fiber is not particularly limited, but an average diameter of 0.3 to 20 μm and an average length of 1 to 50 mm are preferable. If the average diameter of the short fibers is less than 0.3 μm, the production cost becomes remarkably high, and if a porous layer is formed, the strength is remarkably lowered and it becomes difficult to handle the short fibers. On the other hand, when the average diameter exceeds 20 μm, the short fibers are rigid and difficult to be entangled, and in addition, the specific surface area of the short fibers is small and the adhesion rate of the photocatalyst is low, so that the photocatalytic activity is suppressed low. If the average length is less than 1 mm, the entanglement between the short fibers becomes weak and the tensile strength of the non-woven fabric decreases. On the other hand, if the average length exceeds 50 mm, the fibrous opening property of the fiber is lowered, and it becomes difficult to uniformly disperse the fiber in the non-woven fabric, and as a result, it becomes difficult to produce a uniform glass fiber non-woven fabric. The basis weight of glass fiber non-woven fabric is 5 g / m²~ 1,500g / m²The thickness is preferably 0.03 to 5.0 mm.

【0030】

Since the surface of the acid-treated glass fiber cloth is an active silica (silicon oxide) substance having a solid acid and its specific surface area is extremely large, a large amount of polar gas can be adsorbed. By fixing the photocatalyst to this glass fiber cloth, VOCs and the like and odorous gas can be decomposed and removed with high efficiency. The amount of the photocatalyst attached to the porous glass fiber cloth is preferably 0.1 to 40% by weight, more preferably 0.5 to 20% by weight.

【0031】

The type of photocatalyst is not particularly limited, and known titanium oxide, zinc oxide, or the like can be used. Further, the method of fixing the photocatalyst to the porous layer of the glass fiber cloth is not particularly limited, and known means can be used as it is. For example, a chemical vapor deposition method such as a CVD method, a physical vapor deposition method such as a sputtering method, a coating by a sol-gel method, or a method in which ultrafine particles of a photocatalyst are attached and then heated and fixed. Among these, the following method, in which a general-purpose production apparatus can be used and materials are easily available, is preferable. One is a method of coating titania (titanium oxide) sol using a sol-gel method, and the other is a method of immersing a glass fiber cloth in a solution in which ultrafine particles of titania having an average diameter of 10 nm or less are dispersed, and then heating. It is a method of fixing the particles. In the coating of titania sol by this sol-gel method, the glass fiber cloth is immersed in the titania sol solution, dried and fired, so that a Si-O-Ti bond is formed between the glass fiber and titanium oxide, thereby forming a Si-O-Ti bond. The adhesive force of titanium oxide to glass fibers becomes extremely strong. Examples of the precursor of titania sol include titanium alkoxide, titanium chloride, titanium sulfide or titanium acetate. When alcohols are used as a compatible solvent, titanium alkoxide is preferable, and when water is used as a compatible solvent. Is preferably titanium chloride, titanium sulfide or titanium alkoxide. However, when the precursor and the organic substance are compatible with each other, any combination may be selected.

【0032】

When titanium oxide is used as the photocatalyst, anatase-type titanium oxide is preferable. This is because the anatase type has higher reactivity as a photocatalyst than the rutile type or the brookite type. However, since anatase-type titanium oxide shrinks due to heating, it is necessary to pay sufficient attention to the temperature and time when firing by heating in the above method.

【0033】

Further, on the porous layer of the glass fiber cloth, precious metals such as platinum, rhodium, ruthenium, gold, silver or copper or their nitrates, sulfates or acetates (hereinafter, these are collectively referred to as "precious metals"). Is preferably coexisting with the photocatalyst. By coexisting precious metals with the photocatalyst, the reactivity of the photocatalyst can be further enhanced. The method for fixing the noble metals to the porous layer of the glass fiber cloth is not particularly limited, and the photocatalyst fixing treatment and before and after the photocatalyst fixing treatment are not particularly limited. Examples of the method for fixing the precious metals include a method of spraying the metal ionized water of the precious metals on the glass fiber cloth, a method of immersing the glass fiber cloth in the metal ionized water and then irradiating light, or a method of irradiating the glass with the metal ionized water. An example is a method of irradiating light with the fiberglass cloth immersed. By the light irradiation, the photoreduction plating mechanism acts, and the noble metals can be firmly adhered to the porous layer of the glass fiber cloth.

【0034】

Further, in order to enhance the adsorption effect of gas on the glass fiber cloth, an inorganic material having adsorption performance that is not decomposed by the photocatalyst, for example, apatite can be combined with the photocatalyst. Here, apatite refers to any one of calcium phosphate (apatite in a narrow sense) such as tricalcium phosphate and octacalcium phosphate, hydroxyapatite, carbonate apatite and fluoride apatite, or a mixture of two or more thereof.

【0035】

The apatite may be formed after the photocatalyst is fixed on the acid-treated glass fiber cloth, or the photocatalyst may be fixed after the apatite is formed on the acid-treated glass fiber cloth. Further, the apatite and the photocatalyst may be mixed and fixed, or may be compounded.

【0036】

The amount of apatite adhered to the porous glass fiber cloth is preferably 0.1 to 40% by weight. If it is less than 0.1% by weight, the adsorption effect does not appear, while if it exceeds 40% by weight, the effect of acid treatment of the glass cloth diminishes, or when it is formed on the photocatalyst, the photocatalytic activity decreases. More preferably, it is 0.5 to 20% by weight.

【0037】

The method for forming the apatite is not particularly limited, and a general method of immersing the porous glass fiber cloth or the photocatalyst-carrying porous glass fiber cloth as the base material in the simulated body liquid whose pH or the like is adjusted is used. it can. For example, it contains ions such as Na, K, Cl, Ca, P, and Mg and is contained in a simulated body solution having a pH of 7 to 8 at 25 ° C to 60 ° C for about 10 to 30 days, more preferably 30 ° C to 40 °. By immersing in the simulated body solution of C for about 20 minutes to 1 hour, apatite (calcium phosphate) produced by the reaction of calcium hydroxide and phosphate ions can be precipitated on the surface layer of the porous glass fiber.

【0038】

Further, a metal oxide having a photocatalytic action forms a metal-modified apatite in the apatite crystal structure by ion exchange, or a predetermined amount of metal ion of the metal oxide is added to the constituent ions of the apatite in advance. In coexistence, a metal-modified apatite may be formed by the coprecipitation method.

【0039】

Calcium phosphate is porous and has a high affinity (biocompatibility) with proteins and sugars which are biological constituents such as fungi and molds, so that microorganisms such as fungi and molds can be efficiently adsorbed. Therefore, microorganisms such as fungi and molds can be rapidly and continuously redox-decomposed by combining with a glass fiber cloth to which a photocatalyst is fixed. In addition, it is possible to prevent the generation of malodorous substances produced by life activities such as fungi and molds and released to the outside of the cells.

【0040】

The glass fiber cloth in the present invention is not heated at all before the acid treatment, or if it is heated at 300 ° C or less, its average pore diameter is relatively small, so that aldehydes and alcohols having a molecular weight of about 30 to 120 are used. Suitable for decomposing and removing VOCs such as ketones, xylene, toluene, benzene, styrene or phenol, or odorous gases such as ammonia, nitrogen monoxide, nitrogen dioxide, hydrogen sulfide or sulfur dioxide. On the other hand, when heated at 300 to 600 ° C before acid treatment, the average pore size becomes slightly larger, so tributyl phosphate (TBP), dioctyl phthalate (DOP), and dibutyl phthalate having a molecular weight of about 120 to 300 are used. It becomes suitable for decomposition and removal of semi-volatile organic compounds such as (DBP) or diethyl phthalate (DEP).

【0041】

The photocatalyst-supporting glass fiber cloth provided with this photocatalyst in the porous layer is a means for decomposing pollutants in water or air, for example, an air filter device used for air purification in a clean room or a living space, an interior wall material, or the like. Used for.

【0042】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail with reference to Examples. It should be noted that the present invention is not limited to the following examples. (Example 1) A woven fabric made of glass fibers (average fiber diameter 9 μm) having the E glass composition of No. (i) in Table 2 above (meshing 363 g / m).²(Thickness 0.43 mm) was immersed in a 3.0-standard hydrochloric acid aqueous solution at 45 ° C for 24 hours, then thoroughly washed with water and dried to form a porous layer on its surface. For the glass fiber woven fabric provided with this porous layer, the "specific surface area" is measured by the nitrogen adsorption BET method, the "average pore size" is measured by the nitrogen adsorption Inkley method, and the specifications of the glass fiber and the specific gravity before and after the acid treatment are measured. The "external surface area" was calculated from the values. Table 3 shows these measured and calculated values.

【0043】

Next, the porous glass fiber woven fabric was immersed in a solution prepared by dissolving 760 g of titanium isoproproxide and 400 g of an organic resin in 840 g of ethyl alcohol, and the precursor of titanium oxide was uniformly and evenly distributed in the porous layer. Was attached to. This woven fabric was dried at 60 ° C. for 1 hour, then heated to 350 ° C. at a pace of 1 ° C. per minute, and baked as it was for 12 hours. By this heat treatment, the organic resin was completely removed, and the titanium isoproxide was changed to titanium oxide mainly composed of anatase type, and firmly adhered to the surface of the porous layer and in the pores. The amount of titanium oxide adhered was 3.0% by weight with respect to the porous glass fiber cloth.

【0044】

The photocatalyst-supported glass fiber woven fabric thus produced was measured for its ability to decompose and remove VOCs and the like by the following method.

【0045】

[Decomposition and removal test using a closed system] The above photocatalyst-supported glass fiber woven fabric was cut into a size of 10 x 10 cm and placed in a closed container with a volume of about 54 L equipped with a purification fan and a diffusion fan for diffusing injection gas. .. Formaldehyde gas was injected into this closed container, DC10V was constantly applied to the diffusion fan to allow sufficient diffusion, and then the initial concentration was measured. Immediately after that, the black light was turned on and 0.7 mW / cm on the surface of this woven fabric.²DC10V was also applied to the purification fan while irradiating with the ultraviolet rays of the above, and the formaldehyde gas concentration was measured after 30 minutes had passed. The removal rate of formaldehyde gas was calculated from this initial concentration and the concentration after 30 minutes. This removal rate is based on the following formula.

【0046】

Removal rate (%) = 100 × ((initial concentration)-(concentration after 30 minutes)) / (initial concentration) [0047]

Table 4 shows the removal rates when the initial concentrations are 5, 20 and 40 ppm.

【0048】

(Example 2) A porous layer was formed and titanium oxide was added in the same manner as in Example 1 except that the glass fiber woven fabric was heat-treated at 400 ° C for 6 hours (no phase separation occurred) and then acid-treated. It was fixed (titanium oxide adhesion amount 3.0% by weight). Table 3 shows the specific surface area of this woven fabric, and Table 4 shows its decomposition and removal ability.

【0049】

(Comparative Example 1) A porous layer was formed and titanium oxide was fixed in the same manner as in Example 1 except that the glass fiber woven fabric was heat-treated at 700 ° C to separate the phases and then acid-treated. Titanium oxide adhesion 3.5% by weight). Table 3 shows the specific surface area of this woven fabric, and Table 4 shows its decomposition and removal ability.

【0050】

(Comparative Example 2) Titanium oxide was fixed to the surface of the glass fiber woven fabric in the same manner as in Example 1 except that the glass fiber woven fabric was not subjected to acid treatment to form a porous layer (titanium oxide adhered). Amount 2.8% by weight). Table 3 shows the specific surface area of this woven fabric, and Table 4 shows its decomposition and removal ability.

【0051】

(Comparative Example 3) A glass plate made of 97% silicon oxide having a thickness of 0.5 mm was heat-treated at 700 ° C. to separate the phases, and then acid-treated to make the surface porous. This porous glass film (specific surface area 35m)²(/ G average pore size 65.9 nm) was immersed in an isopropyl titanate solution, followed by immersion in a 0.1N hydrochloric acid aqueous solution for 3 hours to hydrolyze, and then dried at 120 ° C. for 1 hour. This operation was repeated 3 times and fired at 550 ° C. for 15 hours to disperse and contain titanium oxide in the porous glass film (titanium oxide content: 3.0% by weight). Table 3 shows the specific surface area of this porous glass film, and Table 4 shows its decomposition and removal ability. In addition, this porous glass film was produced according to the Example of Patent Document 5.

【0052】

(Example 3) A glass fiber woven fabric having a porous layer prepared in the same manner as in Example 1 was prepared by adding 50 g of a titania ultrafine particle sol solution (STS-02) having an average diameter of 7 nm (manufactured by Ishihara Techno Co., Ltd.) to hydrochloric acid having a pH of 1. It was immersed in a well-dissolved solution added to 950 g of an aqueous solution. Then, it was dried at 150 ° C. and further fired at 450 ° C. for 20 minutes to fix titanium oxide to the glass fiber woven fabric (titanium oxide adhesion amount 2.5% by weight). Table 3 shows the specific surface area of this woven fabric, and Table 4 shows its decomposition and removal ability.

【0053】

(Comparative Example 4) Titanium oxide was fixed to the glass fiber woven fabric produced in Comparative Example 1 by the same means as in Example 3 (titanium oxide adhesion amount 3.5% by weight). Table 3 shows the specific surface area of this woven fabric, and Table 4 shows its decomposition and removal ability.

【0054】

[Table 3]<img file="JP2004002176A_D0002.tif" /> 【0055】

From Table 3, 100 m in Examples 1 and 3 in which the glass fiber woven fabric was acid-treated without heat treatment and in Example 2 in which heat treatment was performed but the phase was not separated.²A specific surface area of / g or more and an average pore diameter of 1.0 to 30 nm can be obtained. On the other hand, in Comparative Examples 1 and 4 in which the glass fiber woven fabric was heat-treated at a high temperature to separate the phases and then acid-treated, and the glass film was heat-treated and phase-separated and then acid-treated. In Example 3, the specific surface area obtained is 100 m.²It can be seen that it is less than / g and the average pore diameter is larger than 30 nm.

【0056】

[Table 4]<img file="JP2004002176A_D0003.tif" /> 【0057】

From Table 4, it can be seen that the photocatalyst-supported glass fiber woven fabrics of Examples 1 to 3 can remove 25 ml of 5 ppm formaldehyde gas by 84% or more in about 0.1 to 1.0 seconds.

【0058】

[Effect of the invention]

The photocatalyst-supported glass fiber cloth of the present invention does not significantly impair the original strength of the glass fiber even if it is subjected to heat treatment, acid treatment, or the like. Therefore, even when it is used in an air filter device, it is sufficient for the pressure loss. Can withstand. Further, the porous layer formed on the surface of the glass fiber is characterized in that the specific surface area is relatively large, the pore diameter is an appropriate size, and the external surface area is also relatively large. If a photocatalyst is fixed to the layer, VOCs and other odorous gases can be quickly adsorbed in large amounts and further decomposed and removed. Further, since this glass fiber cloth is subjected to heat treatment and acid treatment after weaving the glass fiber, it is excellent in handleability and can be easily incorporated into an air filter device.