JP2000084414A - Photocatalytic particle and article with photocatalytic function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an article with an photocatalytic function having high purifying capability and a photocatalytic particle to be used therefor. SOLUTION: This photocatalytic particle 1 comprises a glass particle made of an ultraviolet-transmitting glass having a spectro-transmittance at 320 nm in wavelength of at least 50% for 5 mm thickness and a photocatalytic membrane formed on a surface of the glass particle. Further, the article with an photocatalytic function is provided by fusion welding or adhesion of a plurality of photocatalytic particles, the photocatalytic particle comprising a glass particle made of an ultraviolet-transmitting glass having the spectro- transmittance at 320 nm in wavelength of at least 50% for 5 mm thickness and the photocatalytic membrane formed on the surface of the glass particle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to photocatalyst particles and articles having a photocatalytic function.

[0002]

2. Description of the Related Art Photocatalysts that exhibit functions such as antifouling, sterilization, and deodorization by irradiation of ultraviolet rays are known. In recent years, with increasing interest in environmental hygiene, this photocatalytic technology has attracted attention, and building materials and the like having a photocatalytic film formed on the surface of a base material and provided with a water or air purifying function have been proposed.

[0003]

In order to increase the purifying ability by the photocatalyst, it is effective to increase the surface area. Therefore, it has been studied to roughen the surface or make the surface porous.

However, the surface roughening method has a limitation in increasing the surface area, and when the surface is made porous, the amount of ultraviolet rays reaching the internal photocatalyst particles is reduced, so that a sufficient effect cannot be exerted.

An object of the present invention is to provide an article having a photocatalytic function having a high purification ability and photocatalyst particles used for the article.

[0006]

Means for Solving the Problems The photocatalyst particles of the present invention are:
The spectral transmittance at a wavelength of 320 nm is 50 at a thickness of 5 mm.
% Or more of glass particles made of an ultraviolet transmitting glass,
And a photocatalytic film formed on the surface of the glass particles.

In a first embodiment of the article with a photocatalyst function of the present invention, a plurality of photocatalyst particles are fused or adhered, and the photocatalyst particles have a spectral transmittance at a wavelength of 320 nm of 50 mm or more at a thickness of 5 mm. And a photocatalyst film formed on the surface of the glass particles.

In a second embodiment of the article with a photocatalytic function of the present invention, a surface layer composed of a plurality of photocatalyst particles is formed on a substrate, and the photocatalytic particles have a spectral transmittance at a wavelength of 320 nm. It is characterized by comprising glass particles of 5% or more of 5% or more of ultraviolet transmitting glass and a photocatalytic film formed on the surface of the glass particles.

[0009]

In the present invention, the photocatalyst particles of the photocatalyst film on the surface of the glass particles are catalytically activated by ultraviolet rays received from the outside (sunlight, fluorescent lamps, etc.), and oxidize organic substances and the like that have come into contact.
It decomposes and exhibits functions such as antifouling, sterilization, and deodorization.

In the photocatalytic film, TiO ₂ , ZnO, WO ₃ ,
Fe ₂ O ₃ , CdS, ZnS, SrTiO ₃ , K ₄ Nb ₆ O
₁₇ , NaTi ₄ O _{9 and the} like can be used. The thickness of the photocatalyst film is preferably 0.01 to 100 μm.
If the film thickness is thicker than this, the ultraviolet transmittance decreases and the amount of ultraviolet light reaching the internal photocatalyst particles decreases, and if it is smaller than this, the photocatalyst film is liable to be deteriorated due to wear.

The glass particles have a wavelength of 320 nm.
Soda lime gas whose light transmittance is 5% or more and 50% or more
It is made of an ultraviolet transmitting glass such as a glass or borosilicate glass.
If the transmittance is lower than 50%, it will be ultraviolet to internal photocatalyst particles
Products with photocatalyst function that make it difficult to reach the wire and have high purification ability
Can not be obtained. The glass component contains Na _Two
O, K_TwoO, Li_TwoWhen there are many alkaline components such as O
Component and photocatalytic film eluted due to surface degradation
May react and the photocatalytic function may decrease. like this
If necessary, reduce the alkali component of the UV-transmitting glass
Or silica (SiO_Two)
What is necessary is just to form a photocatalyst film through the intermediary.

The shape of the glass particles is not particularly limited, and may be, for example, small spheres, granules, scales, crushed shapes,
A thing having a shape such as a powder or a rod can be used. It is preferable to use glass particles having an average particle size of about 0.01 to 10 mm.

As a method for producing the photocatalyst particles, a method of forming a film on the surface of the glass particles by using a sol-gel method, a CVD method, an evaporation method or the like can be used.

The first embodiment of the article with a photocatalytic function according to the present invention is characterized in that, as shown in FIG. 1, a plurality of photocatalyst particles have a porous shape fused or bonded. Since each photocatalyst particle constituting the article is based on glass particles that transmit ultraviolet light, a large amount of ultraviolet light reaches the inside of the article,
High catalytic activity is obtained.

As a method of manufacturing this type of article, a method of heating the photocatalyst particles to fuse them together or a method of bonding the photocatalyst particles together with an inorganic or organic binder can be used.

Further, as shown in FIG. 2, a second embodiment of the article with a photocatalytic function according to the present invention comprises crystallized glass, sintered glass,
A porous surface layer formed by fusing or adhering a large number of photocatalyst particles is formed on the surface of a base material such as a refractory. Since each photocatalyst particle constituting the surface layer is made of glass particles that transmit ultraviolet light as a base material, even if the film thickness of the surface layer is large, sufficient ultraviolet light reaches inside and high catalytic activity can be obtained. The thickness of the surface layer is preferably about 0.1 to 10 mm.

As a method for producing this type of article, a method in which the photocatalyst particles are fused and integrated with the substrate by heating, or a method in which the photocatalyst particles are adhered to the substrate surface with an inorganic or organic binder can be used. .

In producing the first and second articles with a photocatalyst function, upon fusion or adhesion of the photocatalyst particles,
A conventionally known antibacterial agent powder such as Ag may be added to the binder.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

Example 1 First, a titanium alcoholate solution containing an organic titanium compound as a main component and alcohol as a solvent was prepared as a photocatalyst material.

[0021] As the glass particles, SiO ₂ in% by weight
75.0%, Al ₂ O ₃ 5.0%, MgO 3.5%,
Na ₂ O 10.0%, K ₂ O 1.5%, CaO
_{5.0%, Fe 2 O 3 50ppm} , TiO 2 50ppm
And a small spherical ultraviolet transmitting glass having an outer diameter of 1 to 5 mm was prepared. This glass had a spectral transmittance at 320 nm of 85% at a thickness of 5 mm.

Next, a titanium alcoholate solution is prepared,
After coating on the surface of glass particles by sol-gel method, 50
By baking at 0 ° C., photocatalyst particles having a photocatalyst film having a thickness of about 0.5 μm were obtained. When the surface of the obtained photocatalyst particles was observed by EPMA analysis, it was confirmed that titanium oxide was present on the surface.

Subsequently, the obtained photocatalyst particles were 450 × 45
It was integrated in a mullite mold frame of 0 × 20 mm and heat-treated at 800 ° C. for 30 minutes. Thereafter, when the mold was removed from the refractory mold, a porous sample having a size of 450 × 450 × 10 mm and fused with photocatalyst particles as shown in FIG. 1 was obtained.

Next, the resolution of the malodorous substances was tested. First,
The sample was cut into a size of 50 × 50 × 10 mm to form a test piece, which was put into a 2000 ml test container. Further, 1000 ppm of acetaldehyde was introduced as a test gas, and 8 W black light (ultraviolet light 0.8 mW) was used.
/ Cm ² ) for 60 minutes to measure the concentration after the test. As a result, acetaldehyde was sharply reduced to 50 ppm.

Comparative Example 1 A titanium alcoholate solution was prepared in the same manner as in Example 1. Further, an ultraviolet transmitting glass having the same composition as in Example 1 was formed into a 50 × 50 × 10 mm plate shape.

Next, a titanium oxide film having a thickness of about 0.5 μm was formed on the surface of the glass plate in the same manner as in Example 1.
A sample was obtained.

Using this sample, the resolution of malodorous substances was tested in the same manner as in Example 1. As a result, the concentration of acetaldehyde after irradiation with black light was 300 ppm.

Comparative Example 2 A titanium alcoholate solution was prepared in the same manner as in Example 1.

[0029] As the glass particles, SiO ₂ in% by weight
75.0%, Al ₂ O ₃ 5.0%, MgO 3.5%,
Na ₂ O 10.0%, K ₂ O 1.5%, CaO
5.0%, 500 ppm of Fe ₂ O ₃ , 100 p of TiO ₂
A small spherical glass having a composition of pm and an outer diameter of 1 to 5 mm was prepared. This glass had a spectral transmittance at 320 nm of 5% at a thickness of 5 mm.

Next, photocatalyst particles were prepared in the same manner as in Example 1, and further fused and integrated by the same method to obtain a photocatalytic particle.
A sample having a size of × 450 × 10 mm and having a porous shape in which the photocatalyst particles were fused and integrated was obtained.

Using this sample, the resolution of malodorous substances was tested in the same manner as in Example 1. As a result, the acetaldehyde concentration after irradiation with black light was 200 ppm.

Example 2 Using the sample of Example 1, the resolution of harmful NOx gas was tested. First, 50 ×
A test piece was cut out into a size of 50 × 10 mm to obtain a test piece.
It was put into a 00 ml test container. Further, 100 ppm of NO ₂ was introduced as a test gas, and 20 W of black light (ultraviolet light: 1.0 mW / cm ² ) was irradiated for 60 minutes to measure the concentration after the test. As a result, NO ₂
pm.

(Example 3) First, SiO ₂ 60 by weight was used.
%, Al ₂ O ₃ 6%, CaO 16%, ZnO 5%,
_{BaO 5%, B 2 O 3} 1%, Na 2 O 4%, K 2 O
450 × 450 having a composition of ₂ %, 0.5% of Li ₂ O, and 0.5% of Sb ₂ O ₃ where β-wollastonite is precipitated
A crystallized glass substrate having a size of × 10 mm was prepared.

In the same manner as in Example 1, a titanium alcoholate solution was applied to the surfaces of the glass particles.

Subsequently, the crystallized glass substrate was placed in a mullite mold, and glass particles were accumulated thereon. Then 8
By heat-treating at 00 ° C. for 30 minutes, a sample was obtained in which a porous surface layer (film thickness: 5 mm) in which photocatalytic particles were fused and integrated on the surface of the crystallized glass substrate (FIG. 2). .

Next, a sample piece having a size of 50 × 50 × 15 mm was cut out from the sample, and in the same manner as in Examples 1 and 2, a malodorous substance (acetaldehyde) and a harmful substance (NO
₂ ) The resolution was tested. As a result, the acetaldehyde concentration after the test was 80 ppm, and NO ₂ was 10 ppm.
Was drastically reduced.

These facts indicate that the article with a photocatalytic function of the present invention has high purification ability.

[0038]

As described above, by using the photocatalyst particles of the present invention, an article with a photocatalytic function having high purification ability can be manufactured. The use of the photocatalyst particles is not limited to the production of an article with a photocatalytic function, and the photocatalyst particles themselves may be used as they are as a material for purification, antifouling, sterilization, odor prevention and the like.

The article with a photocatalyst function of the present invention has a high purification ability, and is therefore suitable as a water or air purification material.
Specifically, it is applied to various uses such as building materials such as interior materials, exterior materials, flooring materials, etc., which have an air purification function, containers having antifouling, sterilizing, and deodorizing functions, and filters for water and air purification equipment. It is possible.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a first embodiment of an article with a photocatalytic function of the present invention.

FIG. 2 is an explanatory view showing a second embodiment of the article with a photocatalytic function of the present invention.

[Explanation of symbols]

 1 Photocatalyst particles 2 Substrate

Claims (3)

[Claims] 1. A photocatalyst particle comprising: a glass particle made of an ultraviolet transmitting glass having a spectral transmittance at a wavelength of 320 nm of 5 mm or more and 50% or more; and a photocatalyst film formed on the surface of the glass particle. . 2. A plurality of photocatalyst particles are fused or adhered. The photocatalyst particles have a spectral transmittance at a wavelength of 320 nm, a thickness of 5 mm, a thickness of 5 mm, and a glass particle made of an ultraviolet transmitting glass of 50% or more; And a photocatalyst film formed on the surface of the photocatalyst. 3. A surface layer formed by fusing or adhering a plurality of photocatalyst particles on a base material. The photocatalyst particles have a spectral transmittance at a wavelength of 320 nm of 50 mm or more at a thickness of 5 mm and a thickness of 5 mm. An article with a photocatalytic function, comprising: glass particles made of a certain ultraviolet transmitting glass; and a photocatalytic film formed on the surface of the glass particles.