JP2011178596A - Sintered compact, method for producing the same, photocatalyst, glass granule mixture and slurry mixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photocatalytic functional stock material comprising two or more kinds of different photocatalytic compounds in required sufficient quantity with glass as raw material and having excellent photocatalytic activity. <P>SOLUTION: The method for producing a sintered compact includes: a step of mixing glass granules with different compositions to produce a mixture; and a step of heating the mixture to produce a sintered compact of glass ceramics including crystals having photocatalytic activity. The obtained sintered compact can include two or more kinds of crystals selected from the group consisting of TiO<SB>2</SB>crystals, WO<SB>3</SB>crystals, ZnO crystals, RnNbO<SB>3</SB>crystals and RnTaO<SB>3</SB>crystals (wherein, Rn denotes alkali metals) and their solid solutions. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a photocatalytic functional sintered body using glass, a method for producing the same, a photocatalyst, a glass powder mixture, and a slurry mixture.

  Metal oxides such as titanium oxide, tungsten oxide, and zinc oxide are known to have high photocatalytic activity. These compounds having photocatalytic activity (hereinafter, sometimes simply referred to as “photocatalytic compounds”) generate electrons and holes when irradiated with light having energy higher than the band gap energy, and therefore include a photocatalytic compound. The redox reaction is strongly promoted near the surface of the body. Further, it is known that the surface of the molded body containing the photocatalytic compound has a so-called self-cleaning action in which it is washed with water droplets such as rain because it exhibits hydrophilicity that easily wets water.

As a photocatalyst compound, titanium oxide has been mainly studied. However, since titanium oxide has a band gap of 3 to 3.2 eV, it is necessary to irradiate ultraviolet rays having a wavelength of 400 nm or less. There was a disadvantage that was not obtained. On the other hand, tungsten oxide (for example, WO ₃ ) has a band gap of about 2.5 eV and has a photocatalytic activity that is responsive to visible light.

  By the way, as a technique for supporting a photocatalytic compound on a base material, a technique for forming a film containing the photocatalytic compound on the surface of the base material, a technique for including the photocatalytic compound in the base material, and the like have been studied. As a method for forming a film containing a photocatalytic compound on the surface of a substrate, in addition to a coating method in which a coating film is formed by coating, methods such as sputtering, vapor deposition, sol-gel, CVD (chemical vapor deposition) are known. Yes. For example, Patent Document 1 proposes a photocatalytic coating agent containing a high concentration inorganic titanium compound in an aqueous emulsion having a synthetic resin as a dispersed phase. Patent Document 2 proposes a visible light responsive photocatalytic coating material containing tungsten oxide fine particles having an average particle diameter of 0.01 to 0.05 μm together with a binder. Furthermore, in patent document 3, the photocatalyst coating material containing a zinc oxide is proposed.

On the other hand, as a technology for including a photocatalytic compound in a base material, it relates to titanium oxide. For example, in Patent Document 4, SiO ₂ , Al ₂ O ₃ , CaO, MgO, B ₂ O ₃ , ZrO ₂ , and TiO are used. _A photocatalyst glass containing a predetermined amount of each of the _two components is disclosed.

JP 2008-81712 A JP 2009-56398 A JP 2007-302851 A Japanese Patent Laid-Open No. 9-315837

  As described above, many conventional techniques employ the concept of supporting a photocatalytic compound by forming a film containing the photocatalytic compound on the surface of a substrate. However, a problem common to techniques based on such a concept is that it is difficult to ensure the adhesion between the substrate and the film containing the photocatalytic compound and the durability of the film itself. That is, in the photocatalytic functional product produced by these methods, the film containing the photocatalytic compound may be peeled off from the base material, or the film may deteriorate and the photocatalytic function may be impaired. For example, as in Patent Documents 1 to 3, when a coating film is formed using a paint, the resin and organic binder remaining in the coating film are decomposed by ultraviolet rays or the like, or are oxidized and reduced by the catalytic action of a photocatalytic compound. As a result, there has been a problem that the coating film is likely to deteriorate with time and the durability is not sufficient. In addition, in order to fully extract the activity of the photocatalytic compound supported in the film, it is necessary to process the photocatalytic compound into nano-sized ultrafine particles. There was a problem that the increase in energy facilitates aggregation and is difficult to handle.

  On the other hand, the glass for photocatalysts disclosed in Patent Document 4 differs from other prior art in that titanium oxide is contained in the glass. However, in the technique of Patent Document 4, titanium oxide, which is a photocatalytic compound, does not have a crystal structure and exists in the glass in an amorphous form, so that its photocatalytic activity is weak and insufficient.

  Therefore, the present inventor has conceived that a photocatalytic material having excellent durability and easy handling can be provided by precipitating crystals having photocatalytic activity from glass. In the case where crystals having photocatalytic activity are precipitated in glass, it is important to deposit the target crystals in a necessary and sufficient amount. In addition, if two or more types of crystals having different functions can be simultaneously precipitated in glass, such as a combination of UV-responsive titanium oxide and visible light-responsive tungsten oxide, the mutual functions are complemented. It is considered that a photocatalytic functional material having excellent characteristics can be provided by matching. However, a glass containing a large amount of a photocatalytic compound is very unstable, and it is extremely difficult to precipitate a desired amount of two or more types of photocatalytic compound crystals simultaneously from a single glass composition in a necessary and sufficient amount. It was.

  The present invention has been made in view of the above circumstances, and provides a photocatalytic functional material having an excellent photocatalytic activity by containing two or more different photocatalytic compounds in a necessary and sufficient amount using glass as a raw material. With the goal.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by heating a mixture obtained by mixing two or more kinds of glass powder particles having different compositions. The headline and the present invention were completed. That is, this invention exists in the following (1)-(29).

(1) A step of preparing a mixture by mixing two or more kinds of glass powders having different compositions;
Heating the mixture and producing a sintered body of glass ceramics containing crystals having photocatalytic activity;
The manufacturing method of the sintered compact provided with.

(2) a step of preparing a mixture by mixing two or more kinds of glass powders having different compositions;
Forming the mixture into a molded body having a desired shape;
Heating the molded body to produce a sintered body of glass ceramics containing crystals having photocatalytic activity;
The manufacturing method of the sintered compact provided with.

(3) The crystal having photocatalytic activity includes a TiO ₂ crystal, a WO ₃ crystal, a ZnO crystal, an RnNbO ₃ crystal, an RnTaO ₃ crystal (where Rn means an alkali metal), and a group consisting of these solid solutions. The manufacturing method of the sintered compact as described in said (1) or (2) containing the 2 or more types of crystal | crystallization selected.

(4) The method for producing a sintered body according to any one of (1) to (3), wherein the crystal having the photocatalyst includes a NASICON crystal.

(5) As the two or more kinds of glass particles, at least,
A first glass granule capable of precipitating a first crystal having photocatalytic activity by heating;
A second glass powder capable of precipitating a second crystal having photocatalytic activity, which is different from the first crystal by heating, and
The manufacturing method of the sintered compact in any one of said (1)-(4) using A.

(6) The first powder and the second powder are respectively TiO ₂ crystal, WO ₃ crystal, ZnO crystal, RnNbO ₃ crystal, and RnTaO ₃ crystal (where Rn means an alkali metal) ) And one or more types of crystals selected from the group consisting of these solid solutions can be precipitated. The method for producing a sintered body according to (5) above.

(7) The method for producing a sintered body according to any one of (1) to (6), wherein a particle diameter of the glass powder particles is in a range of 5 nm to 5 mm.

(8) The sintered body according to any one of (1) to (7), which contains one or more components selected from the group consisting of Ag, Cu, Fe, Ce, Au, Pt, Pd, and Re. Manufacturing method.

(9) A photocatalytic functional sintered body produced by the method according to any one of (1) to (8) above.

(10) The sintered body according to (9), wherein the catalytic activity is expressed by light having a wavelength from the ultraviolet region to the visible region.

(11) The sintered body according to (9) or (10) above, wherein the decomposition activity index of methylene blue based on JIS R 1703-2: 2007 is 3 nmol / L / min or more.

(12) A hydrophilic sintered body produced by the method according to any one of (1) to (8) above.

(13) The sintered body according to (12), wherein a contact angle between the surface irradiated with light having a wavelength from the ultraviolet region to the visible region and a water droplet is 30 ° or less.

(14) A photocatalyst having the sintered body according to any one of (9) to (13).

(15) The photocatalyst according to the above (14), which has a granular or fiber form.

(16) A slurry-like mixture containing the photocatalyst according to (14) or (15) above and a solvent.

(17) A photocatalytic member comprising the photocatalyst according to (14) or (15).

(18) A purification device comprising the photocatalyst according to (14) or (15).

(19) A filter comprising the photocatalyst according to (14) or (15).

(20) A glass ceramic composite having a base material and a glass ceramic layer provided on the base material,
The glass-ceramic composite, wherein the glass-ceramic layer includes the sintered body according to any one of (9) to (13).

(21) A glass powder mixture containing two or more types of glass powder having different compositions and capable of depositing crystals having photocatalytic activity by heating.

(22) The crystal having photocatalytic activity includes a TiO ₂ crystal, a WO ₃ crystal, a ZnO crystal, an RnNbO ₃ crystal, an RnTaO ₃ crystal (where Rn means an alkali metal), and a group consisting of these solid solutions. The glass powder mixture as described in said (21) containing 2 or more types of crystal | crystallization selected.

(23) As the two or more kinds of glass particles, at least,
A first glass granule capable of precipitating a first crystal having photocatalytic activity by heating;
A second glass powder capable of precipitating a second crystal having photocatalytic activity, which is different from the first crystal by heating, and
The glass powder mixture as described in any one of (21) and (22) above.

(24) The first glass powder and the second glass powder are respectively TiO ₂ crystal, WO ₃ crystal, ZnO crystal, RnNbO ₃ crystal, RnTaO ₃ crystal (where Rn is an alkali metal) Mean)), and one or more types of crystals selected from the group consisting of these solid solutions can be precipitated.

(25) The glass powder mixture according to any one of (21) to (24), wherein the crystal includes a NASICON type crystal.

(26) A slurry mixture containing the glass powder mixture according to any one of (21) to (25).

(27) A photocatalytic functional sintered body containing a first crystal having a photocatalytic activity and a second crystal having a photocatalytic activity which is different from the first crystal.

(28) The content ratio of the first crystal and the second crystal is 1: x in mass ratio (where x represents a number of 0.01 or more and 0.99) (27 ).

(29) The first crystal and the second crystal are a TiO ₂ crystal, a WO ₃ crystal, a ZnO crystal, an RnNbO ₃ crystal, and an RnTaO ₃ crystal (where Rn means an alkali metal) and these, respectively. The sintered body according to (27) or (28), wherein the sintered body is selected from the group consisting of:

  According to the method for producing a sintered body of the present invention, two or more kinds of glass powders having different compositions are mixed to produce a mixture, and then the mixture is heated to enrich two or more kinds of photocatalytic crystals. Can be obtained. In the method of the present invention, a sintered body containing a plurality of types of photocatalytic crystals in any combination can be easily produced by changing the combination of glass powder particles. Therefore, compared to the case where a plurality of types of photocatalytic crystals are precipitated from a single glass phase, the control of the crystal form of the photocatalytic crystals and the control of the amount of precipitation are much easier, and an excellent photocatalytic functional material can be provided. . Moreover, the sintered compact which has the outstanding photocatalytic activity can be manufactured easily on an industrial scale.

It is an XRD pattern about the sintered compact of Example 2 of this invention. It is drawing (photograph) which shows the state change of MB solution by the presence or absence of ultraviolet irradiation about the sample of Example 1. FIG.

  Hereinafter, embodiments of the present invention will be described in detail.

[Sintered body]
The sintered body obtained by the method for producing a sintered body of the present invention is a glass ceramic containing a crystal having photocatalytic activity (hereinafter sometimes referred to as “photocatalytic crystal”). Here, the photocatalytic crystal is not particularly limited, but for example, TiO ₂ crystal, WO ₃ crystal, ZnO crystal, RnNbO ₃ crystal (here, Rn means an alkali metal), RnTaO ₃ crystal (here Rn means an alkali metal), TiP ₂ O ₇ crystal, (TiO) ₂ P ₂ O ₇ crystal, LiTi ₂ (PO ₄ ) ₃ , NaTi ₂ (PO ₄ ) ₃ , KTi ₂ (PO ₄ ) ₃ MgTi ₄ (PO ₄ ) ₆ , CaTi ₄ (PO ₄ ) ₆ , SrTi ₄ (PO ₄ ) ₆ , BaTi ₄ (PO ₄ ) ₆ , ZnTi ₄ (PO ₄ ) ₆ , Zn ₂ GeO ₄ crystal, ZnSiSO ₄ crystal Etc., and their solid solutions.

  The sintered body of the present invention can contain two or more different types of photocatalytic crystals. That is, the sintered body of the present invention can contain at least a first crystal having a photocatalytic activity and a second crystal having a photocatalytic activity different from the first crystal. In this case, it is an advantage of the present invention that the combination of the photocatalytic crystals and the content (precipitation) ratio of the photocatalytic crystals can be easily controlled in consideration of, for example, the purpose of use of the sintered body and the characteristics of the photocatalytic crystals. By combining two or more types of photocatalytic crystals having similar photocatalytic properties, a sintered body with enhanced photocatalytic properties can be obtained, or by combining two or more types of photocatalytic crystals having different photocatalytic properties, A sintered body having a wide range of photocatalytic properties can be obtained by mutually complementing the photocatalytic properties. Note that the sintered body may contain three different types, and further four or more types of photocatalytic crystals.

The sintered body of the present invention is particularly selected from the group consisting of TiO ₂ crystal, WO ₃ crystal, ZnO crystal, RnNbO ₃ crystal, RnTaO ₃ crystal (where Rn means alkali metal), and solid solutions thereof. It is preferable to include two or more kinds of crystals. Among these, preferable combinations include, for example, a combination of TiO ₂ crystal and WO ₃ crystal, and a combination of TiO ₂ crystal and RnNbO ₃ crystal. As a particularly preferred combination, the sinter includes TiO ₂ crystals and WO ₃ crystals, whereby responsiveness to light having a wide wavelength range from ultraviolet rays to visible rays can be obtained. In this case, the content ratio of the TiO ₂ crystal as the _first crystal and the WO ₃ crystal as the second crystal is 1: x (where x is a number from 0.01 to 0.99). It is preferable that

The photocatalytic crystal may be a NASICON type crystal, particularly RnTi ₂ (PO ₄ ) ₃ , RTi ₄ (PO ₄ ) ₆ (where Rn is one or more selected from Li, Na, K, Rb, Cs). And R is preferably one or both of Mg, Ca, Sr and Ba). By containing these crystals, photocatalytic properties are improved, and mechanical strength, chemical durability, and the like are greatly improved.

  Moreover, it is preferable that the sintered compact of this invention contains the photocatalyst crystal in the range of 1% or more and 98% or less by the volume ratio with respect to the glass total volume. When the content of the photocatalytic crystal is 1% or more, the sintered body can have good photocatalytic properties. On the other hand, when the content rate of the crystal is 98% or less, the sintered body can obtain good mechanical strength. The crystallization rate of the sintered body is preferably 1%, more preferably 5%, and most preferably 10% as a lower limit, preferably 98%, more preferably 95%, and most preferably 90% in volume ratio. And The size of the crystal is preferably 5 nm to 3 μm in average diameter when approximated to a sphere. By controlling the heat treatment conditions, it is possible to control the size of the precipitated crystal phase, but in order to extract effective photocatalytic properties, the crystal size is preferably in the range of 5 nm to 3 μm, and 10 nm to 1 μm. Is more preferable, and the range of 10 nm to 300 nm is most preferable. The crystal grain size and the average value can be estimated from Scherrer's formula from the half width of the XRD diffraction peak. If the diffraction peaks are weak or overlap, measure the diameter of the crystal particle area measured using a scanning electron microscope (SEM) or transmission electron microscope (TEM), assuming that this is a circle. it can. When calculating an average value using a microscope, it is preferable to measure 100 or more crystal diameters at random.

  The sintered body of the present invention preferably exhibits photocatalytic activity by light having a wavelength from the ultraviolet region to the visible region. Here, the light having a wavelength in the ultraviolet region referred to in the present invention is an invisible electromagnetic wave having a wavelength shorter than that of visible light and longer than that of soft X-ray, and the wavelength is in the range of approximately 10 to 400 nm. In addition, the light having a wavelength in the visible region referred to in the present invention is an electromagnetic wave having a wavelength that can be seen by human eyes among electromagnetic waves, and the wavelength is in a range of about 400 nm to 700 nm. When the surface of the sintered body is exposed to light of any wavelength from the ultraviolet region to the visible region, or light of a wavelength in which they are combined, the surface of the sintered body is expressed. Since the adhered dirt substances and bacteria are decomposed by oxidation or reduction reaction, the sintered body can be used for antifouling use or antibacterial use.

  Furthermore, the sintered body of the present invention preferably has a methylene blue decomposition activity index of 3.0 nmol / L / min or more based on JIS R 1703-2: 2007. Photocatalysts have the ability to generate strong oxidizing power when exposed to ultraviolet light, and to decompose the organic matter they touch into carbon dioxide and water. This is called oxidative decomposition performance and can be evaluated by the following self-cleaning performance test. The test piece is brought into contact with water in which an organic dye (methylene blue) is dissolved, and the initial absorbance (degree of light absorption) is measured with a spectrophotometer. Repeat the operation of measuring the absorbance by irradiating with ultraviolet rays for a certain period of time. Since the dye is decomposed by the photocatalyst, the concentration of the solution gradually decreases and becomes transparent, and the absorbance decreases. The degradation rate of the dye can be calculated from the change in concentration over time, and this is an index of the self-cleaning performance (oxidative degradation performance) of the test piece.

  The sintered body of the present invention preferably has a contact angle of 30 ° or less between the surface irradiated with light having a wavelength from the ultraviolet region to the visible region and a water droplet. Thereby, since the surface of the sintered body exhibits hydrophilicity and has a self-cleaning action, the surface of the sintered body can be easily washed with water, and the deterioration of the photocatalytic characteristics due to dirt can be suppressed. The contact angle between the surface of the sintered body irradiated with light and the water droplet is preferably 30 ° or less, more preferably 25 ° or less, and most preferably 20 ° or less.

  The form of the sintered body is not particularly limited, and is in the form of a powder, a slurry, a molded product formed into an arbitrary shape, a composite having a sintered body layer formed on an arbitrary base material, or the like. It can be. In addition, when making a sintered compact into a slurry form, it can prepare in a slurry form using the same solvent, a binder, etc. by the method similar to the slurry-like mixture of the glass granule of the raw material mentioned later.

  Next, although the 1st method and the 2nd method are illustrated and demonstrated about the manufacturing method of a sintered compact, it is not limited to these methods.

[First method]
The first method includes a step of mixing two or more kinds of glass powders having different compositions to prepare a mixture (mixing step), and heating the mixture to form a sintered glass ceramic containing a photocatalytically active crystal. And a manufacturing process (heating process).

<Glass granules>
In the first method, as "two or more kinds of glass powder having different compositions" used as a raw material, at least a first glass powder capable of precipitating a first crystal having photocatalytic activity by heating, It is possible to use a second glass powder that can precipitate a second crystal having photocatalytic activity, which is different from the first crystal by heating. Each of the first glass powder and the second glass powder may be any one that can precipitate one or more kinds of photocatalytic crystals. The kind of the photocatalytic crystal on which the glass particles are deposited is arbitrary. Further, the combination of two or more kinds of photocatalytic crystals precipitated by two or more kinds of glass powder particles is not particularly limited, and any combination can be used. In addition, you may use 3 types and 4 types or more of glass powder bodies from which a composition differs and deposits a different photocatalyst crystal | crystallization.

  Moreover, it is preferable to contain 1 or more types of components chosen from the group which consists of Ag, Cu, Fe, Ce, Au, Pt, Pd, and Re in the glass granular material used as a raw material of a sintered compact. In addition, the glass composition of a glass granular material is mentioned later.

  The particle size of the glass particles used in the first method is easily homogenized by mixing, and the process in which the glass phases derived from the respective glass particles are completely mixed and integrated during heating and firing. In order to form a crystal phase containing crystals having a desired photocatalytic activity from different glass matrices, it is preferably in the range of 5 nm to 5 mm, for example, in the range of 50 nm to 500 μm. More preferably, it is preferably in the range of 100 nm to 100 μm. The average particle diameter of each glass powder to be mixed may be the same or different, but may be the same from the viewpoint of facilitating uniform mixing. preferable.

<Mixing process>
The mixing step of mixing the glass particles is not particularly limited, but for example, two or more kinds of glass particles may be mixed using a mixer until they are in a homogeneous state.

<Heating process>
In the heating step, the glass powder is heated and fired to produce a sintered body having a crystal phase including a photocatalytic crystal. Here, the specific procedure of the heating step is not particularly limited, but the step of gradually raising the temperature of the mixture of glass particles (hereinafter sometimes referred to as “mixture”) to the set temperature, the set temperature of the mixture And a step of gradually cooling the mixture to room temperature. By such heat treatment, a photocatalytic crystal having a desired size of nano to micron units can be uniformly dispersed in the sintered body.

  In the heating step, the mixture may be heated as it is, or the mixture may be placed on an arbitrary substrate and heated. In the case of using a base material, the material of the base material is not particularly limited, but it is preferable to use, for example, an inorganic material such as glass or ceramics, a metal, or the like because it can be easily combined with a photocatalytic crystal. In order to arrange the mixture on the substrate, for example, the slurry containing the mixture is preferably arranged on the substrate with a predetermined thickness and size. Thereby, the sintered compact which has a photocatalytic characteristic can be easily formed on a base material. Here, the thickness of the layer of the sintered body to be formed is preferably 500 μm or less, for example, from the viewpoint of giving sufficient durability so that the sintered body layer does not peel off, and 200 μm or less. It is more preferable that the thickness is 100 μm or less. Examples of the method for arranging the slurry on the substrate include a doctor blade method, a calendar method, a coating method such as spin coating and dip coating, a printing method such as inkjet, bubble jet (registered trademark), offset, a die coater method, and a spray. Method, injection molding method, extrusion molding method, rolling method, press molding method, roll molding method and the like.

  In addition, as a method of arrange | positioning a mixture on a base material, it is not restricted to the method of using the above-mentioned slurry, You may place a mixture directly on a base material. Moreover, it can also be arrange | positioned by mixing with an organic or inorganic binder component, or interposing a binder layer between base materials. In this case, an inorganic binder is preferable in terms of durability against photocatalysis.

  The conditions for the heat treatment in the heating step can be appropriately set according to the composition of the glass body constituting the mixture, the type and amount of the mixed additive, etc., but the glass crystallization treatment can be performed simultaneously with the heat treatment. Select a temperature that can be used. If the heat treatment temperature is too low, a sintered body having a desired crystal phase cannot be obtained. Therefore, firing at a temperature at least higher than the glass transition temperature (Tg) of the glass body is required. Specifically, the lower limit of the heat treatment temperature is the glass transition temperature (Tg) of the glass body, preferably Tg + 50 ° C., more preferably Tg + 100 ° C., and most preferably Tg + 150 ° C. On the other hand, if the heat treatment temperature becomes too high, the crystal phase containing photocatalytic crystals tends to decrease and the photocatalytic properties tend to disappear, so the upper limit of the heat treatment temperature is preferably Tg + 600 ° C. of the glass body, more preferably Tg + 500 ° C. Yes, most preferably Tg + 450 ° C.

  Moreover, it is necessary to set heat processing time according to a glass composition, heat processing temperature, etc. FIG. If the rate of temperature increase is slow, it may be only necessary to heat to the heat treatment temperature. However, as a guideline, it is preferable that the temperature is short when the temperature is high and long when the temperature is low. Specifically, the lower limit of the heat treatment time is preferably 1 minute, more preferably 3 minutes, and most preferably 5 minutes in that crystals can be grown to a certain extent and a sufficient amount of crystals can be precipitated. On the other hand, if the heat treatment time exceeds 24 hours, the target crystals may become too large or other crystals may be formed, and sufficient photocatalytic properties may not be obtained. Therefore, the upper limit of the heat treatment time is preferably 24 hours, more preferably 19 hours, and most preferably 18 hours. Note that the heat treatment time referred to here means the length of a period during which the heat treatment temperature is maintained at a certain level (for example, the set temperature) in the heating process.

  The heating step is preferably performed while exchanging air in a gas furnace, a microwave furnace, an electric furnace, or the like. However, the present invention is not limited to this condition. For example, it may be performed in an inert gas atmosphere, a reducing gas atmosphere, an oxidizing gas atmosphere, or the like.

[Second method]
The second method includes a step of preparing a mixture by mixing two or more kinds of glass powders having different compositions (mixing step), a step of forming the mixture into a molded body having a desired shape (molding step), Heating the molded body to produce a sintered body of glass ceramics containing crystals having photocatalytic activity (heating process). In addition, since the content of the 2 or more types of glass granule used as a raw material with a 2nd method and the mixing process is the same as the said 1st method, description is abbreviate | omitted.

<Molding process>
The molding step is a step of molding the mixture into a predetermined shape. For example, after the mixture is made into a slurry state, the mixture is molded into a predetermined shape, or the mixture is put into a mold and pressed (press molding). It is possible to use a method such as depositing on a refractory and forming. In this case, molding can be facilitated by adding an organic or inorganic binder component to the mixture.

<Heating process>
The heating step in the second method can be carried out under the same heat treatment conditions and heat treatment time as in the first method.

[photocatalyst]
The sintered body produced as described above can be used as a photocatalyst as it is or after being processed into an arbitrary shape. Here, the “photocatalyst” may have any shape such as a bulk state or a powder form. Moreover, the photocatalyst should just have activity of any one or both of the effect | action which decomposes | disassembles organic substance with light, such as an ultraviolet-ray, and the effect | action which makes the contact angle with respect to water small and provides hydrophilicity. This photocatalyst is used as a photocatalyst material, a photocatalyst member (for example, a water purification material, an air purification material, etc.), a hydrophilic material, a hydrophilic member (for example, a panel, a tile, etc.), etc. Available to: In particular, it is preferably used for applications such as tiles, window frames, and building materials. Thereby, since the photocatalytic function is exhibited on the surfaces of these members and the fungi attached to the surfaces are sterilized, the surfaces can be kept hygienic when used in these applications. Further, since the surface of the member has hydrophilicity, dirt attached to the surface when used in these applications can be easily washed away with raindrops or the like.

  Moreover, the sintered compact of this invention can be processed into various forms according to a use. In particular, for example, by adopting the form of glass fiber (glass fiber), the exposed area of the photocatalytic crystal is increased, so that the photocatalytic activity of the sintered body can be further increased.

  Next, a glass fiber and a glass ceramic composite will be described as a typical application example of the photocatalyst.

[Glass fiber]
The glass fiber of the present invention has the general properties of glass fiber. In other words, it has higher tensile strength and specific strength than conventional fibers, large elastic modulus and specific modulus, good dimensional stability, high heat resistance, nonflammability, good chemical resistance, etc. It has merits and can be used for various purposes. Moreover, since it has a photocatalytic crystal inside and on the surface of the fiber, it is possible to provide a fiber structure having photocatalytic properties in addition to the above-described merits and applicable to a wider range of fields. Here, the fiber structure refers to a three-dimensional structure in which fibers are formed as a woven fabric, a knitted fabric, a laminate, or a composite thereof, and examples thereof include a nonwoven fabric.

  Examples of applications that utilize the heat resistance and non-combustibility of glass fiber include curtains, sheets, wall-clothing cloths, insect screens, clothes, or heat insulating materials. Can be given a deodorizing function and a soil decomposing function by photocatalytic action, and the labor of cleaning and maintenance can be greatly reduced.

  Glass fiber is often used as a filter material because of its chemical resistance. However, the glass fiber of the present invention is not only filtered, but also contains malodorous substances, dirt, bacteria, etc. in the object to be treated by photocatalytic reaction. Since it decomposes | disassembles, the purification apparatus and filter which have a more positive purification function can be provided. Furthermore, since the deterioration of the characteristics due to the separation / detachment of the photocatalyst layer hardly occurs, it contributes to extending the life of these products.

  Next, the manufacturing method of the glass fiber of this invention is demonstrated. The method for producing glass fiber of the present invention comprises a step of mixing two or more kinds of glass powders having different compositions to produce a mixture (mixing step), and a step of forming the mixture into a fiber-like molded body (molding). And a step of heating the fiber-shaped molded body to produce a sintered body of glass fiber containing crystals having photocatalytic activity (heating step). In addition, since the general manufacturing method demonstrated as said 1st and 2nd method can also be applied to this specific example in the range which does not contradict, they are used suitably and the overlapping description is abbreviate | omitted.

<Mixing process>
It can be implemented in the same manner as the first and second methods.

<Molding process>
Next, the mixture obtained in the mixing step is kneaded into a resin and formed into a fiber shape. The forming method of the fiber body is not particularly limited, and can be formed using a known technique. For example, when forming into a fiber (long fiber) of a type that can be continuously wound on a winding machine, Spinning may be performed by DM method (direct melt method) or MM method (marble melt method). When forming into short fibers having a fiber length of about several tens of centimeters, a centrifugal method may be used or the long fibers may be cut. Also good. What is necessary is just to select a fiber diameter suitably with a use. However, the thinner the fabric, the higher the flexibility and texture. However, the spinning production efficiency and cost increase, and conversely, if it is too thick, the spinning productivity is improved, but the workability and handleability are poor. Become. When making a textile product such as a woven fabric, the fiber diameter is preferably in the range of 3 to 24 μm, and when making a laminated structure suitable for uses such as a purification device and a filter, the fiber diameter should be 9 μm or more. preferable. Then, depending on the application, it can be made into a cotton shape, or a fiber structure such as roving or cloth can be made.

<Heating process>
Next, the fiber or fiber structure obtained by the above process is heated to mix and integrate the glass powder and volatilize the resin component, and to deposit desired photocatalytic crystals in and on the fiber. The heating step can be performed under the same conditions as in the first method and the second method. When a desired crystal is obtained, it is cooled to outside the crystallization temperature region, and a glass fiber or fiber structure can be obtained as a sintered body in which two or more different photocatalytic crystals are dispersed.

  The glass fiber after the crystal is formed by performing the heating process can exhibit high photocatalytic properties as it is, but the glass around the crystal phase can be obtained by performing an etching process on this glass fiber. Since the phase is removed and the specific surface area of the crystal phase exposed on the surface is increased, the photocatalytic properties of the glass fiber can be further enhanced. Further, by controlling the solution used in the etching process and the etching time, it is possible to obtain a porous fiber in which only the photocatalytic crystal phase remains.

  Examples of the etching method include dry etching, wet etching by immersion in a solution, and combinations thereof. The acidic or alkaline solution used for the immersion is not particularly limited as long as the surface of the glass ceramic can be corroded, and may be, for example, an acid containing fluorine or chlorine (hydrofluoric acid, hydrochloric acid). This etching step may be performed by spraying hydrogen fluoride gas, hydrogen chloride gas, hydrofluoric acid, hydrochloric acid, or the like on the surface of the glass ceramic.

[Glass ceramic composite]
In the present invention, a glass-ceramic composite (hereinafter sometimes referred to as “composite”) includes a glass-ceramic layer and a substrate obtained by heat-treating glass to produce crystals, Among these, the glass ceramic layer is specifically a sintered body layer made of an amorphous solid and a crystal. The glass ceramic layer contains two or more different photocatalytic crystals, and the crystal phase is uniformly dispersed inside and on the surface of the glass ceramic.

  In a preferred embodiment, the method for producing a glass-ceramic composite includes a step of mixing two or more types of glass powders having different compositions to produce a mixture (mixing step), and heating the mixture by placing the mixture on a substrate. And a step (heating step) of forming a glass ceramic layer containing a crystal having photocatalytic activity on a substrate. In addition, since the general manufacturing method demonstrated as said 1st and 2nd method can also be applied to this specific example in the range which does not contradict, they are used suitably and the overlapping description is abbreviate | omitted.

<Mixing process>
It can be implemented in the same manner as the first and second methods.

<Heating process>
In the heating step, the composite is prepared by placing the mixture on the substrate and then heating and firing. Thereby, a glass ceramic layer having a crystal phase containing two or more kinds of photocatalytic crystals is formed on the substrate. Here, the specific procedure of the heating step is not particularly limited, but the step of placing the mixture on the base material, the step of gradually raising the temperature of the mixture placed on the base material to the set temperature, and setting the mixture The step of maintaining the temperature for a certain period of time and the step of gradually cooling the mixture to room temperature may be included.

(Arrangement on the substrate)
First, the mixture is placed on a substrate. Thereby, a photocatalytic characteristic and hydrophilicity can be provided with respect to a wider base material. Although the material of the base material used here is not particularly limited, it is preferable to use, for example, an inorganic material such as glass or ceramic, a metal, or the like because it can be easily combined with the photocatalytic crystal.

  In order to arrange the mixture on the substrate, it is preferable to dispose the slurry containing crushed glass on the substrate with a predetermined thickness and size. Thereby, a glass ceramic layer can be easily formed on a base material. Here, the thickness of the glass ceramic layer to be formed can be appropriately set according to the application of the composite. It is one of the features of the method of the present invention that the thickness of the glass ceramic layer can be set in a wide range. From the viewpoint of giving sufficient durability so that the glass ceramic layer does not peel off, the thickness is preferably, for example, 500 μm or less, more preferably 200 μm or less, and most preferably 100 μm or less. Examples of the method for arranging the slurry on the substrate include a doctor blade method, a calendar method, a coating method such as spin coating and dip coating, a printing method such as inkjet, bubble jet (registered trademark), offset, a die coater method, and a spray. Method, injection molding method, extrusion molding method, rolling method, press molding method, roll molding method and the like.

  In addition, as a method of arrange | positioning a mixture on a base material, it is not restricted to the method of using the above-mentioned slurry, You may place a mixture directly on a base material.

(Heat treatment conditions)
The conditions for the heat treatment in the heating step can be appropriately set according to the composition of the glass body constituting the mixture, the kind and amount of the mixed additive, etc., but it is necessary to perform the crystallization treatment of the glass simultaneously with the heat treatment. is there. If the heat treatment temperature is too low, a sintered body having a desired crystal phase cannot be obtained. Therefore, heating at a temperature at least higher than the glass transition temperature (Tg) of the glass body is required. Specifically, the lower limit of the heat treatment temperature is the glass transition temperature (Tg) of the glass body, preferably Tg + 50 ° C., more preferably Tg + 100 ° C., and most preferably Tg + 150 ° C. On the other hand, if the heat treatment temperature becomes too high, the crystal phase containing photocatalytic crystals tends to decrease and the photocatalytic properties tend to disappear, so the upper limit of the heating temperature is preferably Tg + 600 ° C. of the glass body, more preferably Tg + 500 ° C. Yes, most preferably Tg + 450 ° C.

  The heat treatment time needs to be set according to the composition of the mixture, the heat treatment temperature, and the like. If the rate of temperature increase is slow, it may be only necessary to heat to the heat treatment temperature. However, as a guideline, it is preferable that the temperature is short when the temperature is high and long when the temperature is low. Specifically, the lower limit is preferably 3 minutes, more preferably 5 minutes, and most preferably 10 minutes from the viewpoint that crystals can be grown to a certain extent and a sufficient amount of crystals can be precipitated. On the other hand, if the heat treatment time exceeds 24 hours, the target crystals may become too large or other crystals may be formed, and sufficient photocatalytic properties may not be obtained. Therefore, the upper limit of the heat treatment time is preferably 24 hours, more preferably 19 hours, and most preferably 18 hours. In addition, the heat processing time said here refers to the length of the period when a calcination temperature is hold | maintained more than fixed (for example, the said setting temperature) among heating processes.

[Glass powder mixture]
Next, the glass powder mixture used as a raw material of the sintered body of the present invention will be described.
The glass powder mixture of the present invention is a mixture of two or more kinds of glass powders having different compositions, and can precipitate photocatalytic crystals (preferably two or more kinds of photocatalytic crystals) by heating. This photocatalytic crystal exists or is uniformly dispersed inside and on the surface of the amorphous glass constituting the glass powder. The glass powder particles can take, for example, a form such as a slurry, and can be used for the production of the sintered body or glass ceramic composite of the present invention. Such a glass powder is obtained by pulverizing a glass body obtained from the raw material composition. Glass powder particles do not have photocatalytic properties, and photocatalytic crystals can be deposited by heating the glass powder particles.

<Method for producing glass powder>
Next, the manufacturing method of each glass powder body which comprises a glass powder body mixture is demonstrated. The glass powder can include a vitrification step in which the raw material composition is melted and solidified to vitrify, and a pulverization step in which the obtained glass body is pulverized. In addition, the manufacturing method of a glass granular material can include arbitrary processes other than the process demonstrated below.

(Vitrification process)
In the vitrification step, a predetermined raw material composition is melted, solidified, and vitrified to produce a glass body. Melting is a process of mixing raw materials having a predetermined composition to obtain a melt. More specifically, the raw materials are prepared so that each component of the glass body is within a predetermined content range, mixed uniformly, and then melted in a temperature range of 1250 to 2000 ° C. for 1 to 24 hours and stirred. Homogenize to make a melt. The conditions for melting the raw material are not limited to the above temperature range, and can be appropriately set according to the composition and blending amount of the raw material composition. Next, the melt obtained by melting is cooled and vitrified to produce a glass body. Specifically, a vitrified glass body is formed by flowing out the melt and appropriately cooling it. Here, the conditions for vitrification are not particularly limited, and may be appropriately set according to the composition and amount of the raw material. Moreover, the shape of the glass body obtained at this process is not specifically limited, Although it may be plate shape, a granular form, etc., it is preferable that it is plate shape at the point which can produce a glass body rapidly and in large quantities.

(Crushing process)
In the pulverization step, the glass body is pulverized to produce pulverized glass. The particle diameter and shape of the crushed glass can be appropriately set according to the required accuracy. For example, when sintering is performed after depositing crushed glass on an arbitrary substrate in a later step, the average particle size of the crushed glass may be in units of several mm. On the other hand, when the sintered body is formed into a desired shape, if the average particle size of the pulverized glass is too large, it becomes difficult to form, and therefore the average particle size is preferably as small as possible. Therefore, the upper limit of the average particle diameter of the crushed glass is preferably 5 mm, more preferably 500 μm, and most preferably 100 μm. In addition, the value of D50 (cumulative 50% diameter) when measured by the laser diffraction scattering method can be used for the average particle diameter of pulverized glass, for example. Specifically, a value measured by a particle size distribution measuring apparatus MICROTRAC (MT3300EXII) manufactured by Nikkiso Co., Ltd. can be used.

  The method for pulverizing the glass body is not particularly limited, and can be performed using, for example, a ball mill, a jet mill or the like. It is also possible to carry out the pulverization step while changing the type of pulverizer until the desired particle size is obtained.

  A glass powder mixture can be obtained by combining two or more kinds of glass powder particles obtained as described above and mixing them uniformly.

[Slurry mixture]
A slurry-like mixture can be prepared by mixing the glass powder mixture with an arbitrary solvent or the like. Thereby, application | coating etc. on a base material become easy, for example. Specifically, the slurry can be prepared by adding an inorganic or organic binder and / or solvent to the glass powder mixture.

  Although it does not specifically limit as an inorganic binder, The thing of the property which permeate | transmits an ultraviolet-ray or visible light is preferable, for example, a silicate type binder, a phosphate type binder, an inorganic colloid type binder, an alumina, a silica, a zirconia And the like.

  As the organic binder, for example, a commercially available binder widely used as a molding aid for press molding, rubber press, extrusion molding, or injection molding can be used. Specific examples include acrylic resin, ethyl cellulose, polyvinyl butyral, methacrylic resin, urethane resin, butyl methacrylate, vinyl copolymer and the like.

  As the solvent, for example, known solvents such as water, methanol, ethanol, propanol, butanol, isopropyl alcohol (IPA), acetic acid, dimethylformamide, acetonitrile, acetone, polyvinyl alcohol (PVA) can be used, but the environmental load is reduced. Alcohol or water is preferable because it can be used.

  In order to homogenize the slurry, an appropriate amount of a dispersant may be used in combination. The dispersant is not particularly limited, and examples thereof include hydrocarbons such as toluene, xylene, benzene, hexane, and cyclohexane, ethers such as cellosolve, carbitol, tetrahydrofuran (THF), dioxolane, acetone, methyl ethyl ketone, and methyl isobutyl ketone. And ketones such as cyclohexanone, and esters such as methyl acetate, ethyl acetate, n-butyl acetate and amyl acetate can be used, and these can be used alone or in combination of two or more.

  In addition to the above components, for example, an additive component for adjusting the curing rate and specific gravity can be blended with the slurry-like mixture of the present invention.

  Content of the glass granular material in the slurry-like mixture of this invention can be suitably set according to the use. Therefore, the content of the glass particles in the slurry mixture is not particularly limited, but for example, from the viewpoint of exhibiting sufficient photocatalytic properties, it is preferably 2% by mass, more preferably 3% by mass. %, Most preferably 5% by mass, and from the viewpoint of ensuring fluidity and functionality as a slurry, preferably 80% by mass, more preferably 70% by mass, and most preferably 65% by mass. Can do.

  The slurry mixture of the present invention can be produced by dispersing the glass powder mixture in a solvent. The manufacturing method of the slurry-like mixture of this invention can have further the process of removing the aggregate of a glass granular material. As the particle size of the glass particles decreases, the surface energy tends to increase and the particles tend to aggregate. If the glass particles are agglomerated, uniform dispersion in the slurry-like mixture may not be achieved, and the desired photocatalytic activity may not be obtained. Therefore, it is preferable to provide the process of removing the aggregate of glass powder particles. The removal of the aggregate can be performed by, for example, filtering the slurry mixture. Filtration of the slurry-like mixture can be performed, for example, using a filtering material such as a mesh with a predetermined opening.

  The glass powder mixture of the present invention obtained by the above method and the slurry-like mixture containing the mixture may be used as a photocatalytic functional material, for example, in a paint, a kneaded material that can be molded / solidified. it can.

[Composition of raw glass]
Next, the composition of glass used as a raw material for the sintered body, glass powder mixture, slurry mixture, etc. of the present invention will be described. Here, as representative examples of photocatalytic crystals, TiO ₂ crystals, WO ₃ crystals, ZnO crystals, RnNbO ₃ crystals (where Rn means an alkali metal) or RnTaO ₃ crystals (where Rn means an alkali metal) However, these are merely examples and are not intended to limit the present invention. In addition, in this specification, unless there is particular notice, content of each component which comprises glass shall be displayed by mol% with respect to the total amount of substances of an oxide conversion composition. Here, the “oxide equivalent composition” means that the oxide, composite salt, metal fluoride, etc. used as the raw material of the glass component of the present invention are all decomposed and changed into oxides when melted. It is the composition which described each component contained in glass by making the total substance amount of the said production | generation oxide into 100 mol%. In addition, the content of the metal element component or non-metal element component in this specification is based on the assumption that all of the cation components constituting the glass are made of oxides that are combined with oxygen that can balance the charge. The mass of the entire glass is 100%, and the mass of the metal element component or the non-metal element component is expressed in mass% (extra divided mass% with respect to the oxide-based mass).

[Example of glass composition for producing TiO ₂ crystals]
The TiO ₂ component is contained in a molar ratio of 15% or more and 99% or less with respect to the total amount of the oxide conversion composition, and as an optional component,
The total amount of substance of the oxide composition in terms of, _P 2 _{O 5} component less than 65% 0% by mol%, and / or _B 2 _{O 3} component 0-65%, and / or the SiO ₂ component 0 ˜65% and / or GeO ₂ component is 0 to 65% (however, in terms of mol% with respect to the total substance amount of the oxide conversion composition, P ₂ O ₅ component, B ₂ O ₃ component, SiO ₂ component, And 1 to 65% of at least one of GeO ₂ components);
The total amount of substance of the oxide composition in terms of 0 to 40% of Li ₂ O component in mol%, and / or Na ₂ O component 0-40%, and / or _{K 2} O ingredient 0-40% And / or 0-10% of the Rb ₂ O component and / or 0-10% of the Cs ₂ O component;
0 to 40% of MgO component and / or 0 to 40% of CaO component and / or 0 to 40% of SrO component and / or BaO component in mol% with respect to the total amount of the oxide conversion composition 0 to 40%, and / or ZnO component 0 to 50%;
The total amount of substance of the oxide composition in terms of 0 to 40% of _B 2 _{O 3} component in mole%, and / or _Al 2 _{O 3} component 0-30%, and / or _Ga 2 _{O 3} component 0 30%, and / or _In 2 _{O 3} component 0-10%;
ZrO ₂ component is 0 to 20% and / or SnO component is 0 to 10% in mol% with respect to the total amount of the oxide-converted composition;
Nb ₂ O ₅ component is 0 to 50% and / or Ta ₂ O ₅ component is 0 to 50% and / or WO ₃ component is 0 to 50% by mol% based on the total amount of the oxide-converted composition. % And / or MoO ₃ component 0-50%;
Bi ₂ O ₃ component is 0 to 20% and / or TeO ₂ component is 0 to 20% and / or LnaOb component (wherein Ln is La 1 or more selected from the group consisting of Gd, Y, Ce, Nd, Dy, Yb and Lu, a = 2 and b = 3 for each component excluding Ce, a = 1 and b = 2 for Ce And a M _x O _y component (wherein M is one or more selected from the group consisting of V, Cr, Mn, Fe, Co, Ni), and x and y is the minimum natural number satisfying x: y = 2: (valence of M), respectively, and 0 to 10% in total, and / or As ₂ O ₃ component and / or Sb ₂ O ₃ component in total 0-5%;
At least one nonmetallic element component selected from the group consisting of an F component, a Cl component, a Br component, an S component, an N component, and a C component is 10% or less by mass ratio with respect to the total glass mass of the oxide-converted composition. ;
At least one metal element component selected from the group consisting of Ag, Cu, Fe, Ce, Au, Pt, Pd and Re in a mass ratio of 10% or less with respect to the total glass mass of the oxide equivalent composition;
Glass containing at a blending ratio of

[Example of glass composition for producing WO ₃ crystal]
In mol% with respect to the total amount of substances of oxide equivalent composition,
WO ₃ component is contained in a blending ratio of 10 to 99%, and as an optional component,
The total amount of substance of the oxide composition in terms of, _P 2 _{O 5} component less than 65% 0% by mol%, and / or _B 2 _{O 3} component 0-65%, and / or the SiO ₂ component 0 ˜65% and / or GeO ₂ component is 0 to 65% (however, in terms of mol% with respect to the total substance amount of the oxide conversion composition, P ₂ O ₅ component, B ₂ O ₃ component, SiO ₂ component, And 1 to 65% of at least one of GeO ₂ components);
0 to 60% of TiO ₂ component in mol% with respect to the total amount of substances of oxide conversion composition;
The total amount of substance of the oxide composition in terms of 0 to 40% of Li ₂ O component in mol%, and / or Na ₂ O component 0-40%, and / or _{K 2} O ingredient 0-40% And / or 0-10% of the Rb ₂ O component and / or 0-10% of the Cs ₂ O component;
0 to 40% of MgO component and / or 0 to 40% of CaO component and / or 0 to 40% of SrO component and / or BaO component in mol% with respect to the total amount of the oxide conversion composition From 0 to 40%;
Al ₂ O ₃ component is 0 to 30% and / or Ga ₂ O ₃ component is 0 to 30% and / or In ₂ O ₃ component is 0% by mol% with respect to the total amount of the oxide-converted composition. -10%;
0 to 20% of ZrO ₂ component in mol% and / or SnO component, SnO ₂ component, and SnO ₃ component in a total of 0 to 10% in terms of mol% with respect to the total amount of the oxide conversion composition;
Nb ₂ O ₅ component is 0 to 50% and / or Ta ₂ O ₅ component is 0 to 50% and / or MoO ₃ component is 0 to 50% by mol% based on the total amount of the oxide conversion composition. %;
0 to 50% of ZnO component and / or 0 to 20% of Bi ₂ O ₃ component and / or 0 to 20% of TeO ₂ component in mol% with respect to the total amount of the oxide-converted composition, and / or / Or Ln ₂ O ₃ component (wherein Ln is a group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) 1 to 30% selected in total) and / or M _x O _y component (wherein M is selected from the group consisting of V, Cr, Mn, Fe, Co, Ni) 1 or more, and x and y are the minimum natural number satisfying x: y = 2: M valence, respectively)) in total 0 to 10%, and / or As ₂ O ₃ component and / or Sb ₂ O ₃ components in total 0 to 5%;
At least one nonmetallic element component selected from the group consisting of F, Cl, Br, S, N, and C in an externally divided mass ratio of 15% or less with respect to the total mass of the glass;
At least one metal element component selected from the group consisting of Ag, Cu, Fe, Ce, Au, Pt, Pd, and Re in an externally divided mass ratio of 10% or less with respect to the total glass mass;
Glass containing at a blending ratio of

[Example of glass composition for producing ZnO crystal]
With respect to the total amount of substances with oxide equivalent composition,
It contains a ZnO component at a blending ratio of 15 to 70%, and as an optional component,
30 or more of at least one component selected from the group consisting of SiO ₂ component, GeO ₂ component, B ₂ O ₃ component, and P ₂ O ₅ component in mol% with respect to the total amount of the oxide-converted composition. ~ 70%;
The total amount of substance of the oxide composition in terms of, 0-30% of Li ₂ O component in mol%, and / or Na ₂ O component 0-30%, and / or _{K 2} O ingredient 0-30% And / or Rb ₂ O component 0-20% and / or Cs ₂ O component 0-20%;
The MgO component is 0-30% and / or the CaO component is 0-30%, and / or the SrO component is 0-30%, and / or the BaO component in mol%, based on the total amount of the oxide-converted composition. 0-30%;
The total amount of substance of the oxide composition in terms of, 0-35% of _Al 2 _{O 3} component in mole%, and / or _Ga 2 _{O 3} component 0 to 35%, and / or _In 2 _{O 3} component 0 -10%;
ZrO ₂ component is 0 to 20% and / or TiO ₂ component is 0 to 40% and / or SnO component, SnO ₂ component, and SnO ₃ component in mol% with respect to the total substance amount of oxide conversion composition 0-10% in total;
The Nb ₂ O ₅ component is 0 to 20% and / or the Ta ₂ O ₅ component is 0 to 20% and / or the WO ₃ component is 0 to 40% by mol% based on the total amount of the oxide-converted composition. % And / or MoO ₃ component 0-10%;
The Bi ₂ O ₃ component is 0 to 20% and / or the TeO ₂ component is 0 to 20% and / or the Ln ₂ O ₃ component (in the formula, Ln is at least one selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) , 0 to 20% in total, and / or M _x O _y component (wherein M is one or more selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, and x and y are 0 to 5% in total, and / or As ₂ O ₃ component and / or Sb ₂ O ₃ component in total 0 to 5 %;
At least one nonmetallic element component selected from the group consisting of F, Cl, Br, S, N, and C is 20% or less in an externally divided mass ratio with respect to the total mass of the glass;
At least one metal element component selected from the group consisting of Ag, Cu, Fe, Ce, Au, Pt, Pd, and Re in an externally divided mass ratio of 10% or less with respect to the total glass mass;
Glass containing at a blending ratio of

[Example of glass composition for producing RnNbO ₃ crystal (where Rn represents an alkali metal)]
In mol% with respect to the total amount of substances of oxide equivalent composition,
Nb ₂ O ₅ component is contained at a blending ratio of 5 to 50%, and as an optional component,
30% to 75% of one or more components selected from the group consisting of SiO ₂ component, B ₂ O ₃ component, and P ₂ O ₅ component in mol% with respect to the total amount of the oxide-converted composition;
5-40 Rn ₂ O and / or RO component (where Rn means an alkali metal and R means an alkaline earth metal) in mol% with respect to the total amount of the oxide conversion composition. %;
0 to 35% of Ta ₂ O ₅ component in mol% with respect to the total amount of the oxide-converted composition;
0 to 20% of TiO ₂ component and / or ZrO ₂ component in mol% with respect to the total amount of the oxide conversion composition;
0 to 30% of Al ₂ O ₃ component in mol% with respect to the total amount of substances in oxide equivalent composition
With respect to the total amount of substances with oxide equivalent composition,
0 to 20% GeO ₂ component and / or 0 to 20% Ga ₂ O ₃ component and / or 0 to 10% In ₂ O ₃ component and / or 0 to 10% SnO component and / or Or 0-20% Bi ₂ O ₃ component, and / or 0-20% TeO ₂ component, and / or 0-20% WO ₃ component, and / or 0-20% MoO ₃ component, and / or Or 0 to 5% in total of As ₂ O ₃ component and / or Sb ₂ O ₃ component;
Ln ₂ O ₃ component (wherein Ln is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, in mol% with respect to the total amount of oxide-converted composition) , Ho, Er, Tm, Yb, and Lu means one or more selected from the group consisting of Lu), 0 to 10% in total;
M _x O _y component (wherein M is one or more selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni) in mol% with respect to the total amount of the oxide-converted composition. X and y are the smallest natural numbers satisfying x: y = 2: M valence, respectively), and 0 to 10% in total;
At least one nonmetallic element component selected from the group consisting of F, Cl, and Br is 15% or less in an externally divided mass ratio with respect to the total mass of the glass;
At least one metal element component selected from the group consisting of Ag, Cu, Fe, Ce, Au, Pt, Pd and Re in an outer mass ratio of 5% or less with respect to the total mass of the glass;
Glass containing at a blending ratio of
In addition, the molar ratio of the oxide conversion composition, the Nb ₂ O ₅ and / or Ta ₂ O _{5 with} respect to the total amount of the Rn ₂ O and / or RO components (Rn and R have the same meaning as described above), and Ratio of total amount of one or more components selected from the group consisting of TiO ₂ , ZrO ₂ and Al ₂ O ₃ [(Nb ₂ O ₅ + Ta ₂ O ₅ + TiO ₂ + ZrO ₂ + Al ₂ O ₃ ) / (Rn ₂ O + RO)] is preferably greater than 1.

[Example of glass composition for producing RnTaO ₃ (where Rn represents an alkali metal)]
In mol% with respect to the total amount of substances of oxide equivalent composition,
It contains Ta ₂ O ₅ component at a blending ratio of 5 to 50%, and as an optional component,
30% to 75% of one or more components selected from the group consisting of SiO ₂ component, B ₂ O ₃ component, and P ₂ O ₅ component in mol% with respect to the total amount of the oxide-converted composition;
5-40% of Rn ₂ O and / or RO component (Rn and R have the same meaning as described above) in mol% with respect to the total amount of the oxide-converted composition;
0 to 35% of Nb ₂ O ₅ component in mol% with respect to the total amount of substances in oxide equivalent composition;
0 to 20% of TiO ₂ component and / or ZrO ₂ component in mol% with respect to the total amount of the oxide conversion composition;
0 to 30% of Al ₂ O ₃ component in mol% with respect to the total amount of substances in oxide equivalent composition;
In mol% with respect to the total amount of substances of oxide equivalent composition,
0 to 20% GeO ₂ component and / or 0 to 20% Ga ₂ O ₃ component and / or 0 to 10% In ₂ O ₃ component and / or 0 to 10% SnO component and / or Or 0-20% Bi ₂ O ₃ component, and / or 0-20% TeO ₂ component, and / or 0-20% WO ₃ component, and / or 0-20% MoO ₃ component, and / or Or 0 to 5% in total of As ₂ O ₃ component and / or Sb ₂ O ₃ component;
Ln ₂ O ₃ component (wherein Ln is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, in mol% with respect to the total amount of oxide-converted composition) , Ho, Er, Tm, Yb, and Lu means one or more selected from the group consisting of Lu), 0 to 10% in total;
M _x O _y component (where M is one or more selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni, in mol% with respect to the total amount of oxide-converted composition) X and y are the smallest natural numbers satisfying x: y = 2: M valence, respectively), and 0 to 10% in total;
At least one non-metallic element component selected from the group consisting of F, Cl, and Br is 15% or less in an externally divided mass ratio with respect to the total mass of the glass;
At least one metal element component selected from the group consisting of Ag, Cu, Fe, Ce, Au, Pt, Pd and Re in an outer mass ratio of 5% or less with respect to the total mass of the glass;
Glass containing at a blending ratio of
In addition, in the molar ratio of the oxide conversion composition, the Ta ₂ O ₅ and / or Nb ₂ O _{5 with} respect to the total amount of the Rn ₂ O and / or RO components (Rn and R have the same meaning as described above), and Ratio of total amount of one or more components selected from the group consisting of TiO ₂ , ZrO ₂ and Al ₂ O ₃ [(Ta ₂ O ₅ + Nb ₂ O ₅ + TiO ₂ + ZrO ₂ + Al ₂ O ₃ ) / (Rn ₂ O + RO)] is preferably greater than 1.

The contents of each component listed in the above composition are as follows.
The TiO ₂ component is a component that precipitates a crystal of TiO ₂ or a crystal of a compound with phosphorus from glass and exhibits strong photocatalytic activity particularly in the ultraviolet region. In particular, when a TiO ₂ crystal is contained in combination with a WO ₃ crystal or a ZnO crystal, photocatalytic activity having responsiveness to a wide range of wavelengths from ultraviolet to visible light can be imparted to the glass ceramic. As crystal forms of titanium oxide, anatase type, rutile type and brookite type are known, but anatase type and brookite type are preferable, and anatase type oxidation having particularly high photocatalytic properties. It is advantageous to contain titanium. Further, when the TiO ₂ component is contained in combination with the P ₂ O ₅ component, it becomes possible to precipitate the TiO ₂ crystal at a lower heat treatment temperature, and the photocatalytic activity is increased from the anatase TiO ₂ crystal having a high photocatalytic activity. The phase transition to a low rutile type can be reduced. Moreover, since the TiO ₂ component also has an effect of acting as a nucleating agent for other photocatalytic crystals, it contributes to the precipitation of other photocatalytic crystals. However, when the content of TiO ₂ component is too large, vitrification becomes very difficult. TiO ₂ component can be introduced into the glass by using as the starting material for example TiO ₂ or the like.

The WO ₃ component is a component that precipitates in the glass as WO ₃ crystals and brings photocatalytic properties to the crystallized glass. Since WO ₃ absorbs visible light up to a wavelength of 480 nm and exhibits photocatalytic activity, it imparts visible light-responsive photocatalytic properties to crystallized glass. WO ₃ is known to have cubic, tetragonal, orthorhombic, monoclinic and triclinic crystal structures, but as long as it has photocatalytic activity, But you can. Moreover, it is a component which improves the meltability and stability of glass, and is a component which improves a photocatalytic characteristic by being dissolved in other photocatalyst crystals, or existing in the vicinity. However, if the content of the WO ₃ component is too large, the stability of the glass is remarkably deteriorated. The WO ₃ component can be introduced into the glass using, for example, WO ₃ as a raw material.

The ZnO component is a component that precipitates in the glass as ZnO crystals and brings photocatalytic properties to the glass ceramic. Moreover, it is a component which improves the meltability and stability of glass. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, when the content of the ZnO component is too large, the stability of the glass is remarkably deteriorated. The ZnO component can be introduced into the glass using, for example, ZnO as a raw material.

The Nb ₂ O ₅ component is a component that precipitates in the glass as a niobate crystal and brings photocatalytic properties to the glass ceramic. Moreover, it is a component which improves the meltability and stability of glass, and is a component which improves a photocatalytic characteristic by being dissolved in other photocatalyst crystals, or existing in the vicinity. However, when the content of Nb ₂ O ₅ component is too large, stability of the glass is significantly deteriorated. Niobate RnNbO ₃ (where Rn means an alkali metal) is considered to be a composite oxide of Nb ₂ O ₅ and an oxide of another element. As its crystal, for example, lithium niobate ( Examples include LiNbO ₃ ) crystals, sodium niobate (NaNbO ₃ ) crystals, and potassium niobate (KNbO ₃ ) crystals. The Nb ₂ O ₅ component can be introduced into the glass using, for example, Nb ₂ O ₅ as a raw material.

The Ta ₂ O ₅ component is a component that precipitates in the glass as a tantalate crystal and brings photocatalytic properties to the glass ceramic. Moreover, it is a component which improves the stability of glass, and is a component which improves the photocatalytic characteristic by being dissolved in other photocatalyst crystals or existing in the vicinity thereof, and can be optionally added. However, when the content of the Ta ₂ O ₅ component is too large, the stability of the glass is remarkably deteriorated. The tantalate RnTaO ₃ (where Rn means an alkali metal) is considered to be a composite oxide of Ta ₂ O ₅ and an oxide of another element, and its crystal is, for example, lithium tantalate (LiTaO ₃ ) Crystals, sodium tantalate (NaTaO ₃ ) crystals, potassium tantalate (KTaO ₃ ) crystals, and the like. The Ta ₂ O ₅ component can be introduced into the glass using, for example, Ta ₂ O ₅ as a raw material.

P ₂ O ₅ component is a component which constitutes the network structure of the glass is a component that can be added optionally. By making the glass cell into phosphate-based glass in which the P ₂ O ₅ component is the main component of the network structure, more TiO ₂ component, WO ₃ component or ZnO component can be incorporated into the glass. Further, by blending the P ₂ O ₅ component, it is possible to precipitate photocatalytic crystals at a lower heat treatment temperature, and in the case of containing a TiO ₂ component, photocatalytic activity from anatase-type TiO ₂ crystals having high photocatalytic activity. The effect of reducing the phase transition to a low rutile type can also be expected. However, the photocatalyst crystals hardly precipitate the content of P ₂ O ₅ is too large. The P ₂ O ₅ component is introduced into the glass using, for example, Al (PO ₃ ) ₃ , Ca (PO ₃ ) ₂ , Ba (PO ₃ ) ₂ , NaPO ₃ , BPO ₄ , H ₃ PO _4, etc. as raw materials. be able to.

The B ₂ O ₃ component is a component that constitutes a glass network structure and improves the stability of the glass, and can be optionally added. However, when there is too much the content, the tendency for a photocatalyst crystal to precipitate hard will become strong. B ₂ O ₃ component may be, for example, as a raw material _{H 3 BO 3, Na 2 B} 4 O 7, Na 2 B 4 O 7 · 10H 2 O, with BPO ₄ or the like is introduced into the glass.

The SiO ₂ component is a component that constitutes a glass network structure and improves the stability and chemical durability of the glass, and is present in the vicinity of the photocatalytic crystal on which Si ⁴⁺ ions are deposited, contributing to the improvement of the photocatalytic activity. It is a component and can be optionally added. However, when the content of SiO ₂ component is too large, the melting property of the glass is deteriorated, the photocatalyst crystals hardly precipitate. SiO ₂ component may be incorporated in the glass by using a raw material such as _{SiO 2, K 2 SiF 6,} Na 2 SiF 6 or the like.

The GeO ₂ component is a component having a function similar to that of the above-described SiO ₂ and can be arbitrarily added to the glass. The GeO ₂ component can be introduced into the glass using, for example, GeO ₂ as a raw material.

Li 2 _O component improves the meltability and stability of glass is a component that hardly generated cracks in the glass ceramics after heat treatment, is a component that can be added optionally. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, when the content of Li 2 _O component is too much, rather the stability of the glass is deteriorated, it becomes difficult precipitation of the photocatalyst crystals. Li ₂ O component may be incorporated in the glass by using, for example, _Li 2 _CO 3 as a raw material, LiNO _3, LiF and the like.

Na 2 _O component improves the meltability and stability of glass is a component that hardly generated cracks in the glass ceramics after heat treatment, is a component that can be added optionally. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, when the content of the Na ₂ O component is too large, the stability of the glass is worsened and the photocatalytic crystals are difficult to precipitate. Na ₂ O component may be incorporated in the glass by using a raw material as for example _{Na 2 O, Na 2 CO 3} , NaNO 3, NaF, Na 2 S, the Na 2 SiF ₆ or the like.

K 2 _O component improves the meltability and stability of glass is a component that hardly generated cracks in the glass ceramics after heat treatment, is a component that can be added optionally. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, when the content of K 2 _O component is too much, rather the stability of the glass is deteriorated, it becomes difficult precipitation of the photocatalyst crystals. K ₂ O component may be material as for example _{K 2 CO 3, KNO 3,} KF, with KHF _2, K ₂ SiF ₆ such that incorporated in the glass.

The Rb ₂ O component is a component that improves the meltability and stability of the glass and makes it difficult to cause cracks in the glass ceramic after the heat treatment, and can be optionally added. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, when the content of the Rb ₂ O component is too large, the stability of the glass is deteriorated, and the precipitation of the photocatalytic crystal becomes difficult. The Rb ₂ O component can be introduced into the glass using, for example, Rb ₂ CO ₃ , RbNO ₃ or the like as a raw material.

Cs 2 _O component improves the meltability and stability of glass is a component which hardly caused cracks in the glass ceramics after heat treatment, is a component that can be added optionally. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, when the content of Cs 2 _O component is too much, rather the stability of the glass is deteriorated, it becomes difficult precipitation of the photocatalyst crystals. Cs ₂ O component may be incorporated in the glass by using as the starting material for example _Cs 2 _{CO 3,} CsNO 3, and the like.

The MgO component is a component that improves the meltability and stability of the glass and can be arbitrarily added. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, when the content of the MgO component is too large, the stability of the glass is worsened, and the photocatalytic crystals are difficult to precipitate. The MgO component can be introduced into the glass using, for example, MgCO ₃ or MgF ₂ as a raw material.

A CaO component is a component which improves the meltability and stability of glass, and is a component which can be added arbitrarily. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, when the content of the CaO component is too large, the stability of the glass is deteriorated, and the photocatalytic crystals are difficult to precipitate. The CaO component can be introduced into the glass using, for example, CaCO ₃ or CaF ₂ as a raw material.

A SrO component is a component which improves the meltability and stability of glass, and is a component which can be added arbitrarily. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, when the content of the SrO component is too large, the stability of the glass is worsened and the photocatalytic crystals are difficult to precipitate. The SrO component can be introduced into the glass using, for example, Sr (NO ₃ ) ₂ , SrF ₂ or the like as a raw material.

A BaO component is a component which improves the meltability and stability of glass, and is a component which can be added arbitrarily. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, if the content of the BaO component is too large, the stability of the glass is rather deteriorated and it is difficult to deposit photocatalytic crystals. The BaO component can be introduced into the glass using, for example, BaCO ₃ , Ba (NO ₃ ) ₂ , BaF ₂ or the like as a raw material.

Here, RO (wherein R is one or more selected from the group consisting of Mg, Ca, Sr and Ba) and Rn ₂ O (wherein Rn consists of Li, Na, K, Rb and Cs) By containing two or more of components selected from the group (one or more selected from the group), the stability of the glass is greatly improved, the mechanical strength of the glass ceramic after the heat treatment is further increased, and the photocatalytic crystal Is more likely to precipitate from the glass. Therefore, the glass ceramic preferably contains two or more of the components selected from the RO component and Rn 2 _O components.

Al ₂ O ₃ component enhances the stability of glass and the chemical durability of glass ceramics, promotes the precipitation of photocatalytic crystals from glass, and improves the photocatalytic properties by dissolving Al ³⁺ ions in the photocatalytic crystals. It is a component that contributes and can be optionally added. However, when there is too much the content, melt | dissolution temperature will raise remarkably and it will become difficult to vitrify. The Al ₂ O ₃ component can be introduced into the glass using, for example, Al ₂ O ₃ , Al (OH) ₃ , AlF ₃ or the like as a raw material.

The Ga ₂ O ₃ component is a component that enhances the stability of the glass, promotes the precipitation of the photocatalytic crystal from the glass, and contributes to the improvement of the photocatalytic properties by Ga ³⁺ ions being dissolved in the photocatalytic crystal. It is a component that can be added. However, when there is too much the content, melt | dissolution temperature will raise remarkably and it will become difficult to vitrify. Ga ₂ O ₃ component can be introduced into the glass by using as the starting material for example _Ga 2 _{O 3,} GaF 3, and the like.

The In ₂ O ₃ component is a component having an effect similar to that of the above Al ₂ O ₃ and Ga ₂ O ₃ and can be optionally added. The In ₂ O ₃ component can be introduced into the glass using, for example, In ₂ O ₃ or InF ₃ as a raw material.

The ZrO ₂ component is a component that enhances the chemical durability of the glass ceramic, promotes the precipitation of the photocatalytic crystal, and contributes to the improvement of the photocatalytic properties by the solid solution of Zr ⁴⁺ ions in the photocatalytic crystal, and can be arbitrarily added. It is an ingredient. However, when the content of the ZrO ₂ component is too large, it becomes difficult to vitrify. The ZrO ₂ component can be introduced into the glass using, for example, ZrO ₂ , ZrF ₄ or the like as a raw material.

SnO component, SnO ₂ component, SnO ₃ component promotes precipitation of photocatalytic crystals, suppresses reduction of Ti ⁴⁺ , W ⁶⁺ , Zn ^2+, etc., makes it easy to obtain photocatalytic crystals, and dissolves in photocatalytic crystals. It is a component that is effective in improving photocatalytic properties, and when it is added together with Ag, Au, or Pt ions, which will be described later, which acts to enhance the photocatalytic activity, it acts as a reducing agent, and indirectly increases the photocatalytic activity. It is a component that contributes to improvement, and can be optionally added. However, SnO component, SnO ₂ component, the content of SnO ₃ components too large, stability of the glass is deteriorated, the photocatalytic properties tend to decrease. The SnO component, SnO ₂ component, and SnO ₃ component can be introduced into the glass using, for example, SnO, SnO ₂ , SnO ₃ or the like as a raw material.

The MoO ₃ component is a component that improves the meltability and stability of the glass, and is a component that improves the photocatalytic properties by being dissolved in the photocatalytic crystal or in the vicinity thereof, and can be optionally added. is there. However, if the content of the MoO ₃ component is too large, the stability of the glass is remarkably deteriorated. The MoO ₃ component can be introduced into the glass using, for example, MoO ₃ as a raw material.

Bi ₂ O ₃ component is a component for enhancing the meltability and stability of glass and is a component that can be added optionally. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, when the content of Bi ₂ O ₃ component is too large, stability of the glass is deteriorated, precipitation of the photocatalyst crystals is difficult. The Bi ₂ O ₃ component can be introduced into glass using, for example, Bi ₂ O ₃ as a raw material.

TeO ₂ component is a component which enhances the meltability and stability of glass and is a component that can be added optionally. In addition, it is a component that lowers the glass transition temperature to make it easier to produce photocatalytic crystals and lowers the heat treatment temperature. In addition, by suppressing the heat treatment temperature, an effect of reducing phase transition from anatase-type TiO ₂ crystal having a high photocatalytic activity to a rutile type having a low photocatalytic activity when a TiO ₂ component is contained can be expected. However, when the content of TeO ₂ component is too large, stability of the glass is deteriorated, precipitation of the photocatalyst crystals is difficult. The TeO ₂ component can be introduced into the glass using, for example, TeO ₂ as a raw material.

Ln ₂ O ₃ component (wherein Ln is selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) Is a component that improves the chemical durability of the glass ceramic, and is a component that improves the photocatalytic properties by being dissolved in the photocatalytic crystal or in the vicinity thereof, and is optional. It is a component that can be added. Among Ln ₂ O ₃ components, especially Ce ₂ O ₃ component prevents the reduction of Ti ⁴⁺ , W ⁶⁺ , Zn ^2+, etc., and promotes the precipitation of photocatalytic crystals, so it has the effect of contributing significantly to the improvement of photocatalytic properties. . However, if the total content of the Ln ₂ O ₃ components is too large, the stability of the glass is significantly deteriorated. The Ln ₂ O ₃ component includes, for example, La ₂ O ₃ , La (NO ₃ ) ₃ .XH ₂ O (X is an arbitrary integer), Gd ₂ O ₃ , GdF ₃ , Y ₂ O ₃ , YF ₃ , CeO as raw materials. ₂ , CeF ₃ , Nd ₂ O ₃ , Dy ₂ O ₃ , Yb ₂ O ₃ , Lu ₂ O _{3 and the} like can be used for introduction into the glass.

M _x O _y component (wherein M is one or more selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, and x and y are valences of x: y = 2: M, Is the minimum natural number that satisfies the above condition), or is present in the vicinity of the photocatalytic crystal or contributes to the improvement of the photocatalytic properties and absorbs visible light of some wavelengths into the glass ceramic. It is a component that imparts an appearance color, and is an optional component.

As ₂ O ₃ component and / or Sb ₂ O ₃ component is a component for clarifying and defoaming glass, and when added together with Ag, Au, and Pt ions, which will be described later, and has the effect of enhancing photocatalytic activity. Since it plays the role of a reducing agent, it is a component that indirectly contributes to the improvement of the photocatalytic activity and can be optionally added. However, if the total content of these components is too large, the stability of the glass is deteriorated, and the photocatalytic properties are liable to deteriorate. As ₂ O ₃ component and Sb ₂ O ₃ component are, for example, As ₂ O ₃ , As ₂ O ₅ , Sb ₂ O ₃ , Sb ₂ O ₅ , Na ₂ H ₂ Sb ₂ O ₇ .5H ₂ O and the like as raw materials. And can be introduced into the glass.

The components for clarifying and defoaming the glass are not limited to the above As ₂ O ₃ component and Sb ₂ O ₃ component. For example, such as CeO ₂ component, TeO ₂ component, etc. Well-known fining agents and defoaming agents in the field, or a combination thereof can be used.

In the present invention, the glass may contain at least one nonmetallic element component selected from the group consisting of an F component, a Cl component, a Br component, an S component, an N component, and a C component. These components are components that improve the photocatalytic properties by being dissolved in the photocatalyst crystal or in the vicinity thereof, and can be optionally added. However, if the total content of these components is too large, the stability of the glass is remarkably deteriorated and the photocatalytic properties are liable to deteriorate. These non-metallic element components are preferably introduced into the glass in the form of alkali metal or alkaline earth metal fluoride, chloride, bromide, sulfide, nitride, carbide or the like. The raw material of the non-metallic element component is not particularly limited. For example, ZrF ₄ , AlF ₃ , NaF, CaF _{2 and the} like are used as the raw material for the F component, NaCl and AgCl are used as the raw material for the Cl component, NaBr is used as the raw material for the Br component, S It can be introduced into glass by using NaS, Fe ₂ S ₃ , CaS ₂ or the like as component raw materials, AlN ₃ or SiN ₄ or the like as N component raw materials, TiC, SiC or ZrC or the like as C component raw materials. it can. These raw materials may be added in combination of two or more, or may be added alone.

  In the present invention, the glass may contain at least one metal element component selected from Ag, Cu, Fe, Ce, Au, Pt, Pd and Re. These metal element components are components that improve photocatalytic activity by being present in the vicinity of the photocatalytic crystal, and can be optionally added. However, if the total content of these metal element components is too large, the stability of the glass is remarkably deteriorated, and the photocatalytic properties tend to be lowered.

  In the present invention, components other than the above components can be added to the glass as needed within a range that does not impair the properties of the glass ceramic. However, lead compounds such as PbO, and components of Th, Cd, Tl, Os, Se, and Hg tend to refrain from being used as harmful chemical substances in recent years. Not only glass manufacturing processes but also processing processes and products Environmental measures are required until disposal after conversion. Therefore, when importance is placed on the environmental impact, it is preferable not to substantially contain them except for inevitable mixing. As a result, the glass ceramics are substantially free of substances that pollute the environment. Therefore, the glass ceramics can be manufactured, processed, and discarded without taking any special environmental measures.

  EXAMPLES Next, although an Example demonstrates this invention in more detail, this invention is not restrict | limited to a following example.

Examples 1 to 23:
Glass powder particles having the compositions A to J shown in Table 1 were prepared. As a raw material for the glass powders A to J, any of the high-purity materials used for ordinary glasses such as oxides, hydroxides, carbonates, nitrates, fluorides, chlorides, metaphosphate compounds, etc. The raw materials were selected and used. These raw materials are weighed so as to have the composition ratio shown in Table 1 and uniformly mixed, and then put into a platinum crucible. The temperature is 1200 ° C. to 1600 ° C. in an electric furnace depending on the melting difficulty of the glass composition. After melting in the temperature range for 1 to 24 hours, stirring and homogenizing, the glass melt was dropped into running water to obtain a granular or flaky glass body. By pulverizing this glass body with a jet mill, glass particles A to J having a particle size (average particle diameter) of about 10 μm were obtained. Next, the glass powder granules of A to J were uniformly mixed at the mixing ratio shown in Table 2, formed into pellets, and then fired under the firing conditions shown in Table 2. That is, the pellet was heated to the temperature described in each Example of Table 2, and the temperature was maintained for the time described, and crystallization was performed simultaneously with firing. Then, it cooled and obtained the sintered body of the glass ceramics which has the target crystal | crystallization. Table 2 shows the main types of crystals precipitated in the sintered bodies of the examples.

  Here, the types of precipitated crystals of the glass ceramics of Examples 1 to 23 were identified by an X-ray diffractometer (manufactured by Philips, trade name: X'Pert-MPD).

As shown in Table 2, the sintered bodies of Examples 1 to 23 are respectively TiO ₂ crystal, WO ₃ crystal, ZnO crystal, RnNbO ₃ crystal, and RnTaO ₃ crystal (where Rn means an alkali metal) And two or more kinds of crystals selected from the group consisting of these solid solutions were confirmed.

Next, in order to investigate the structure of the precipitated crystals, the sintered body of Example 2 was subjected to X-ray diffraction analysis (XRD). The results are shown in FIG. In the XRD pattern of Example 2, the peak of the anatase type TiO ₂ crystal represented by “◯” including the incident angle 2θ = 25.3 ° and “□” including the incident angle 2θ = 24.2 °. The peak of the NaTi ₂ (PO ₄ ) ₃ crystal represented by the above and the peak of the WO ₃ monoclinic or triclinic crystal represented by “Δ” including the incident angle of 2θ = 23.5 ° were confirmed. . Therefore, the sintered body of Example 2 contains TiO ₂ crystal, NaTi ₂ (PO ₄ ) ₃ crystal and WO ₃ crystal having high photocatalytic activity, and is excellent by combining these photocatalytic properties. It was inferred that it exhibited photocatalytic activity.

In addition, about the sintered bodies obtained in Examples 1, 2, 9, 10, and 11, 0.5 g of a sample (granular shape having a particle diameter of 1 to 3 mm) after etching with 46% by mass of hydrofluoric acid for 1 minute was added. The MB concentration when immersed in a methylene blue (MB) solution and irradiated with ultraviolet rays having an illuminance of 1 mW / cm ² for 3 to 10 hours and the MB concentration when not irradiated were evaluated visually by the following five criteria. . The evaluation results of the MB decomposition ability are shown in Table 3.

(Criteria)
5: Slightly thin, almost unchanged 4: Slightly thin 3: Thin 2: Pretty thin 1: Nearly transparent, almost transparent

  As shown in Table 3, it was confirmed that the sintered bodies of Examples 1, 2, 9, 10, and 11 had excellent MB decomposition activity.

  Moreover, the photograph which shows the state change of MB solution by the presence or absence of ultraviolet irradiation about the sample of Example 1 was shown in FIG. As shown in FIG. 2, when the ultraviolet ray was irradiated, the blue color of the MB solution disappeared and became transparent, but when the ultraviolet ray was not irradiated, the blue color did not change.

As the above experimental results show, the sintered body of the glass ceramics of Examples 1 to 23 containing a combination of a plurality of photocatalytic crystals such as TiO ₂ crystal and WO ₃ crystal has excellent photocatalytic activity. In addition, since the photocatalytic crystals are uniformly dispersed in the glass, it was confirmed that there is no loss of the photocatalytic function due to peeling and that it can be used as a photocatalytic functional material excellent in durability.

As described above, according to the method for producing a sintered body of the present invention, two or more kinds of glass powders having different compositions are mixed to produce a mixture, and then the mixture is heated to produce two or more kinds. Thus, a sintered body containing abundant photocatalytic crystals can be obtained. In the method of the present invention, by changing the combination of glass powder particles, for example, a plurality of TiO ₂ crystals, WO ₃ crystals, ZnO crystals, RnNbO ₃ crystals, RnTaO ₃ crystals (where Rn means an alkali metal), etc. A sintered body containing various kinds of photocatalytic crystals in any combination can be easily produced. Therefore, compared to the case where a plurality of types of photocatalytic crystals are precipitated from a single glass phase, the control of the crystal form of the photocatalytic crystals and the control of the amount of precipitation are much easier, and an excellent photocatalytic functional material can be provided. . Moreover, the sintered compact which has the outstanding photocatalytic activity can be manufactured easily on an industrial scale.

As mentioned above, although embodiment of this invention was described in detail for the purpose of illustration, this invention is not restrict | limited to the said embodiment. Those skilled in the art can make many modifications without departing from the spirit and scope of the present invention, and these are also included within the scope of the present invention.

Claims (29)

Mixing two or more kinds of glass powders having different compositions to produce a mixture;
Heating the mixture and producing a sintered body of glass ceramics containing crystals having photocatalytic activity;
The manufacturing method of the sintered compact provided with. Mixing two or more kinds of glass powders having different compositions to produce a mixture;
Forming the mixture into a molded body having a desired shape;
Heating the molded body to produce a sintered body of glass ceramics containing crystals having photocatalytic activity;
The manufacturing method of the sintered compact provided with. The crystal having photocatalytic activity is selected from the group consisting of TiO ₂ crystal, WO ₃ crystal, ZnO crystal, RnNbO ₃ crystal, RnTaO ₃ crystal (where Rn means an alkali metal), and a solid solution thereof. The manufacturing method of the sintered compact of Claim 1 or 2 containing a 2 or more types of crystal | crystallization.   The method for producing a sintered body according to claim 1, wherein the crystals having photocatalytic activity include NASICON type crystals. As the two or more kinds of glass particles, at least,
A first glass granule capable of precipitating a first crystal having photocatalytic activity by heating;
A second glass powder capable of precipitating a second crystal having photocatalytic activity, which is different from the first crystal by heating, and
The manufacturing method of the sintered compact in any one of Claim 1 to 4 which uses this. The first glass powder and the second glass powder are respectively a TiO ₂ crystal, a WO ₃ crystal, a ZnO crystal, an RnNbO ₃ crystal, and an RnTaO ₃ crystal (where Rn means an alkali metal). 6. The method for producing a sintered body according to claim 5, wherein one or more kinds of crystals selected from the group consisting of these solid solutions can be precipitated.   The method for producing a sintered body according to any one of claims 1 to 6, wherein a particle diameter of the glass powder particles is in a range of 5 nm to 5 mm.   The sintered body according to any one of claims 1 to 7, wherein the glass powder contains one or more components selected from the group consisting of Ag, Cu, Fe, Ce, Au, Pt, Pd, and Re. Manufacturing method.   A photocatalytic functional sintered body produced by the method according to claim 1.   The sintered body according to claim 9, wherein catalytic activity is expressed by light having a wavelength from an ultraviolet region to a visible region.   The sintered body according to claim 9 or 10, wherein the decomposition activity index of methylene blue based on JIS R 1703-2: 2007 is 3.0 nmol / L / min or more.   A hydrophilic sintered body produced by the method according to claim 1.   The sintered body according to claim 12, wherein a contact angle between the surface irradiated with light having a wavelength from the ultraviolet region to the visible region and a water droplet is 30 ° or less.   A photocatalyst having the sintered body according to claim 9.   The photocatalyst of Claim 14 which has a granular form or a fiber form. A slurry mixture containing the photocatalyst according to claim 14 or 15 and a solvent.   The photocatalyst member which has a photocatalyst of Claim 14 or 15.   The purification apparatus which has a photocatalyst of Claim 14 or 15.   A filter comprising the photocatalyst according to claim 14 or 15. A glass ceramic composite having a base material and a glass ceramic layer provided on the base material,
The glass-ceramic composite, wherein the glass-ceramic layer includes the sintered body according to any one of claims 9 to 13.   A glass powder mixture containing two or more types of glass powder having different compositions and capable of depositing crystals having photocatalytic activity by heating. The crystal having photocatalytic activity is selected from the group consisting of TiO ₂ crystal, WO ₃ crystal, ZnO crystal, RnNbO ₃ crystal, RnTaO ₃ crystal (where Rn represents an alkali metal) and a solid solution thereof 2 The glass powder mixture according to claim 21, comprising at least seed crystals. As the two or more kinds of glass particles, at least,
A first glass powder capable of precipitating a first crystal having photocatalytic activity by heating;
A second glass powder body capable of precipitating a second crystal having photocatalytic activity, which is different from the first crystal by heating,
The glass powder mixture according to claim 21 or 22, comprising: The first glass powder and the second glass powder are respectively a TiO ₂ crystal, a WO ₃ crystal, a ZnO crystal, an RnNbO ₃ crystal, and an RnTaO ₃ crystal (where Rn means an alkali metal). 24. The glass powder mixture according to claim 23, wherein one or more types of crystals selected from the group consisting of these solid solutions can be precipitated.   The glass powder mixture according to any one of claims 21 to 24, wherein said crystal includes a NASICON type crystal.   A slurry mixture containing the glass powder mixture according to any one of claims 21 to 25.   A sintered body having a photocatalytic function, comprising: a first crystal having photocatalytic activity; and a second crystal having photocatalytic activity different from the first crystal.   28. The content ratio of the first crystal and the second crystal is 1: x in terms of mass ratio (where x means a number of 0.01 or more and 0.99). Sintered body. The first crystal and the second crystal are respectively a TiO ₂ crystal, a WO ₃ crystal, a ZnO crystal, an RnNbO ₃ crystal, and an RnTaO ₃ crystal (where Rn means an alkali metal) and a solid solution thereof. The sintered body according to claim 27 or 28, wherein the sintered body is selected from the group consisting of: