JP2011241092A - Glass ceramics and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocatalytic function material containing a photocatalyst at high concentration to exhibit excellent photocatalytic activity and also excellent in usability and durability by using glass as a raw material.SOLUTION: There is provided a glass ceramic material containing 5-50 mol% of TiOcomponent, 2-50 mol% of SrO component and 10-85 mol% of SiOcomponent based on the total mass of the composition in terms of oxide. The glass ceramic material preferably contains strontium titanate SrTiOcrystal and its solid solution crystal. The glass ceramic material may take forms of bulk, powder, fiber, slurry mixture, sintered material, composite with a substrate, etc.

Description

The present invention relates to a glass ceramic and a manufacturing method thereof.

Strontium titanate (SrTiO ₃ ) is a crystal having a perovskite structure and is known as a photocatalytic material having a decomposition activity ability. A photocatalyst causes an oxidation or reduction reaction in the vicinity of its surface by involving electrons and holes generated by irradiating a semiconductor having a photocatalytic function with light having energy higher than its band gap energy. In particular, surface treatment using crystals with high catalytic activity is generally well known.

For example, in order to manufacture a member having a photocatalytic action, a photocatalytic coating agent containing titanium oxide as a photocatalyst to be applied to the surface is disclosed (for example, Patent Document 1). In this way, photocatalytic action can be added only to the surface while maintaining the mechanical properties of the substrate, which is very convenient. However, in application and coating, the durability of the coating film and the coating layer is not sufficient, and peeling becomes a problem depending on the use situation.

On the other hand, as an example of putting a photocatalytic material in the material, as a photocatalyst (apatite having titanium as a metal atom necessary for having photocatalytic activity (photocatalytic titanium apatite)) with respect to polypropylene resin, Disclosed is a photocatalyst composite material in which 30% by mass of calcium / titanium hydroxyapatite is added, kneaded and formed into a ball shape (spherical shape) having a diameter of 3 cm, crushed by a breaker, and adjusted to a particle size of about 5 mm square with a sieve. (For example, Patent Document 2). However, this is a problem in which calcium / titanium hydroxyapatite is bound with a polypropylene resin as a binder, and the resin binder is decomposed by the decomposition activity of the photocatalyst present in the material, resulting in deterioration of the material.

On the other hand, as a bulk body containing strontium titanate, a technique is disclosed in which glass and an inorganic filler such as strontium titanate are mixed, molded, and fired to obtain a bulk body (for example, Patent Document 3). However, this requires the glass and ceramics once produced to be pulverized and mixed, which increases the number of processes. Furthermore, it is known that the particle shape and size of the photocatalyst material affect the photocatalytic activity, but it is difficult to control the ceramic particle size in the method of mixing and firing glass powder and ceramic powder. It is difficult to expect catalytic activity.

JP 2008-81712 A JP 2008-36465 A JP 2008-37739 A

As described above, when a film is formed with the photocatalytic material on the surface of the substrate, the photocatalytic function such as peeling may be impaired due to the adhesion between the film and the substrate and the durability of the film itself. In addition, since a resin or an organic binder is often used for the coating material used for the coating film, there is a problem that fogging or white blurring occurs due to a change with time due to ultraviolet rays, acid rain, or the like. Moreover, in order to fully extract the activity of the photocatalyst supported in the film, it is necessary to process the photocatalyst into nano-sized ultrafine particles. However, nano-sized ultrafine particles increase the production cost and increase the surface energy. There is a problem that it is easy to agglomerate due to the increase and is difficult to handle. On the other hand, when forming a film by sputtering or the like, there is no problem of film adhesion and particle size miniaturization, but it is necessary to strictly control the conditions at the time of film formation, the film formation speed is slow, and the substrate on which film formation is possible There are problems such as limited shape.

The present invention has been made in view of the above, and it is not necessary to process a thin film or a coating on the surface, can be molded into a desired shape by a relatively easy method, and has a photocatalytic property as a bulk material, Specifically, an object of the present invention is to provide a glass ceramic in which fine crystals having excellent durability and photocatalytic properties are present inside or on the surface of the material. Furthermore, it aims at providing the photocatalyst functional molded object containing the manufacturing method of the glass ceramic, and the glass ceramic manufactured by this manufacturing method.

The present inventor found that crystals having photocatalytic properties can be used as an excellent photocatalytic functional material by generating crystals in glass, and the present invention has been completed. Specifically, the following are provided.

(1) Glass ceramics containing crystals of strontium titanate (SrTiO ₃ ) and / or a solid solution thereof and having photocatalytic activity.

(2) The content of TiO ₂ component is 5% to 50%, 2% to 50% of SrO component, and 10% to 85% of SiO ₂ component in mol% with respect to the total substance amount of oxide conversion composition (1) Glass ceramics.

(3) Rn ₂ O component 0 to 40% and / or RO component 0 to 50% and / or Al ₂ O ₃ component 0 to 20% in mol% with respect to the total amount of substances of the oxide conversion composition, And / or ZrO ₂ component 0-10%, and / or Nb ₂ O ₅ component and / or Ta ₂ O ₅ component 0-25%, and / or As ₂ O ₃ component and / or Sb ₂ O ₃ component 0 5%
The glass ceramic according to (1) or (2), which contains each component of
(In the formula, Rn is one or more selected from the group consisting of Li, Na, K, Rb, and Cs, and R is one or more selected from the group consisting of Mg, Ca, Ba, and Zn)

(4) The glass ceramic according to any one of (1) to (3), wherein catalytic activity is expressed by light having a wavelength from the ultraviolet region to the visible region.

(5) The glass ceramic according to any one of (1) to (4), wherein the decomposition activity index of methylene blue based on Japanese Industrial Standard JIS R 1703-2: 2007 is 3.0 nmol / l / min or more.

(6) A method for producing a glass ceramic according to any one of (1) to (5),
A melting step of mixing raw materials to obtain a melt;
A first cooling step for lowering the temperature of the melt to a crystallization temperature range;
A crystallization step of maintaining the temperature within the crystallization temperature region to produce crystals;
A second cooling step of obtaining a crystal-dispersed glass by lowering the temperature to outside the crystallization temperature region.

(7) A method for producing a glass ceramic according to any one of (1) to (5),
A melting step of mixing raw materials to obtain a melt;
A cooling step of cooling the melt to obtain glass;
A reheating step of raising the temperature of the glass to a crystallization temperature region;
A crystallization step of maintaining the temperature within the crystallization temperature region to produce crystals;
A re-cooling step of obtaining a crystal-dispersed glass by lowering the temperature outside the crystallization temperature region.

(8) The method for producing glass ceramics according to (6) or (7), wherein the crystallization temperature region is 580 ° C. or higher and 1100 ° C. or lower.

(9) A photocatalyst comprising the glass ceramic according to any one of (1) to (5).

(10) The photocatalyst according to (9), which has a granular or fiber form.

(11) A slurry-like mixture containing the photocatalyst according to (10) and a solvent.

(12) A photocatalytic functional member comprising the photocatalyst according to any one of (9) and (10).

(13) A sintered body obtained by sintering pulverized glass, wherein the sintered body includes the glass ceramic according to any one of (1) to (5). .

(14) The obtained glass body was prepared so as to contain 5 to 50% of the TiO ₂ component, ₂ to 50% of the SrO component, and 10 to 85% of the SiO ₂ component in mol% of the oxide conversion composition. By melting and vitrifying the raw material composition, a vitrification step for producing a glass body, a crushing step for crushing the glass body to produce a crushed glass, and molding the crushed glass into a molded body having a desired shape. The sintered body according to (13), which is produced by a method comprising a molding step and a sintering step in which the molded body is heated to produce a sintered body.

(15) The sintered body according to (14), wherein the method further includes a step of mixing one or more kinds of crystals selected from TiO ₂ crystals, WO ₃ crystals, and ZnO crystals into the crushed glass.

(16) A composite having a base material and a photocatalytic functional layer provided on the base material, wherein the photocatalytic functional layer contains the glass ceramic according to any one of (1) to (5) A glass-ceramic composite characterized by

(17) Raw material composition prepared such that the obtained glass body contains 5% to 50% of TiO ₂ component, ₂ to 50% of SrO component, and 10 to 85% of SiO ₂ component based on mol% of oxide A vitrification step for producing a glass body by melting and vitrifying an object, a crushing step for crushing the glass body to produce a crushed glass, and heating and firing after placing the crushed glass on a substrate The composite according to (16), which is produced by a method comprising a firing step.

(18) The composite according to (17), wherein the method further comprises a step of mixing one or more kinds of crystals selected from TiO ₂ crystals, WO ₃ crystals, and ZnO crystals into the crushed glass.

(19) A glass that produces crystals having photocatalytic activity from glass by heating and becomes the glass ceramic according to any one of (1) to (5).

(20) The glass according to (19), which has a granular or fiber form.

(21) A slurry mixture containing the glass according to (20) and a solvent.

According to the present invention, by setting the composition of the glass within a predetermined range, the photocatalytic crystal of strontium titanate (SrTiO ₃ ) or strontium titanate solid solution is easily precipitated. Since this crystal phase is uniformly deposited on the inside and the surface of the glass, there is no problem of peeling of the surface, and even if the surface is scraped, the photocatalytic performance is not inferior, and the glass ceramic having excellent durability and its manufacturing method Obtainable.

It is an XRD pattern of the glass ceramics containing a strontium titanate crystal of Example 9 of the present invention. It is the same composition as Example 9 of this invention, and is a graph showing the crystallization temperature and the crystallinity degree of the glass ceramic produced by changing crystallization temperature. It is an XRD pattern of the glass-ceramic sintered compact containing the strontium titanate crystal of Example 14 and Example 15 of this invention. In the graph, 1 represents Example 14 and 2 represents Example 15. It is an XRD pattern of the glass-ceramics composite containing the strontium titanate crystal of Example 16.

The reason why the crystal phase and the components contained in the glass ceramic of the present invention are limited as described above will be described below. The description of the content of each component is expressed in mol% based on oxide unless otherwise specified. It is assumed that all anionic components in the glass ceramics are oxygen, and when considering only the content of the cation component, all of the cation component is made of an oxide combined with oxygen that balances the charge. And each component contained in the glass is expressed by the mole fraction of oxides × 100.

The glass ceramic in the present invention is a material obtained by precipitating a crystalline phase in a glass phase by heat-treating the glass, and not only a material composed of a glass phase and a crystalline phase, but also the glass phase is entirely a crystalline phase. In other words, a material having a crystal amount (crystallinity) in the material of 100 wt% may be included. Engineering ceramics and ceramic sintered bodies obtained from commonly used powders are difficult to become pore-free fully sintered bodies. Therefore, the glass ceramics of the present invention can be distinguished from those glass ceramics by the presence of such pores (for example, porosity). Glass ceramics can be used as an effective means for producing desired crystals in the production of a photocatalytic material because the crystal grain size, the type of precipitated crystals, and the degree of crystallization can be controlled by controlling the crystallization process.

The glass ceramic of the present invention contains one or more crystals selected from strontium titanate (SrTiO ₃ ) and strontium titanate solid solution. By including these crystals, the glass ceramic of the present invention can be provided with a photocatalytic function.

Strontium titanate (SrTiO ₃ ) is not only excellent as a photocatalyst but also has a chemically stable property that is not affected by most acids, bases, and organic solvents, and is safe for the human body. . A solid solution means a state in which two or more kinds of metal solids or non-metal solids are dissolved in each other at an atomic level to form a uniform solid phase as a whole, and may be called a mixed crystal. Depending on how the solute atoms permeate, there are interstitial solid solutions in which elements smaller than the gaps in the crystal lattice enter, and substitutional solid solutions in which they replace the parent phase atoms. Here, the strontium titanate solid solution means that a part of Sr is replaced with one or more of Ca, Ba, K, Rb, La, Ce, and / or a part of Ti is Zr, Hf, V, Nb, Ta, Al. , Ga, Mg, Cr, Fe, and a compound substituted with one or more of Li. The band gap energy can be adjusted by substituting the component constituting the strontium titanate (SrTiO ₃ ) crystal with another component. In addition, the substitution of the component also has an effect of distorting the crystal structure, and can further enhance the photocatalytic activity. The solid solution material is not limited to the above, and part of Ti is Zn, Mn, Co, Ni, Cu, Sc, and Li, and part of Sr is Na, Eu, Cd, Pb, Bi, and the like. In some cases, a substitution or interstitial solid solution is taken. Furthermore, strontium and their solid solutions titanate is not limited to simple perovskite structure _can also take the _{Sr n + 1 Ti n O 3n} + 1 layered perovskite structure represented by like. In the present specification, these crystals may be collectively referred to as “photocatalytic crystals”.

In addition to the SrTiO ₃ crystal, the glass ceramic of the present invention includes TiO ₂ , SiO ₂ , alkali metal titanate silicate complex salt crystal, alkaline earth metal titanate silicate crystal, alkali metal alkaline earth metal titanate silicate One or more of a composite salt crystal, an alkali metal silicate, an alkaline earth metal silicate crystal, an alkali metal titanate crystal, and an alkaline earth metal titanate crystal can be included without impairing the photocatalytic activity. In particular, TiO ₂ and titanate crystals are photocatalytic substances, and the photocatalytic activity is improved. In addition, the mechanical strength of the glass ceramics can be improved by controlling the heat treatment conditions so that the crystals are intertwined.

The amount of the crystal phase with respect to the entire glass ceramic of the present invention can be freely selected according to the purpose of use, such as placing importance on transparency or giving priority to photocatalytic properties, but is in the range of 1% to 85% by volume ratio. It is preferable that The amount of crystal phase precipitated from the glass can be controlled by controlling the heat treatment conditions. If the amount of the crystal phase is large, the photocatalytic function tends to be high, but the brittleness and transparency of the entire glass ceramic may be lowered, so the amount of the crystal phase is set to a range of 85% or less by volume ratio. Preferably, it is more preferably 82% or less, and most preferably 80% or less. On the other hand, if the amount of the crystal phase is small, effective photocatalytic properties cannot be obtained. Therefore, the amount of the crystal phase is preferably 1% or more by volume ratio, more preferably 2% or more, and most preferably 3% or more. preferable.

Glass ceramic of the present invention preferably contains in the range of TiO ₂ component of 5-50%. The TiO ₂ component is an essential and indispensable component that precipitates from the glass as a crystal of a SrTiO ₃ crystal and its solid solution, or a compound with an alkali metal or other alkaline earth metal, and provides photocatalytic properties. In particular, by setting the content of the TiO ₂ component to 5% or more, the photocatalytic crystal is easily precipitated, and the concentration of the TiO ₂ crystal in the glass ceramic is increased, so that desired photocatalytic characteristics can be ensured. On the other hand, when the content of the TiO ₂ component exceeds 50%, devitrification occurs or phase separation tends to occur. Accordingly, the content of the TiO ₂ component with respect to the total amount of the glass ceramics in the oxide conversion composition is preferably 5%, more preferably 8%, most preferably 10%, and preferably 50%, more preferably 40%. %, Most preferably 35%. The TiO ₂ component is contained in the glass ceramic by using, for example, anatase type, rutile type or brookite type TiO ₂ , alkali / alkaline earth titanate, alkali / alkaline earth titanic acid silicate complex salt as a raw material. be able to.

The SrO component is an indispensable and indispensable component for crystallizing the SrTiO ₃ crystal and its solid solution or other titanate crystal from the glass to bring about photocatalytic properties to the glass ceramic of the present invention. . In particular, unless the content of the SrO component is 2% or more, it becomes difficult to precipitate SrTiO ₃ crystals and crystals of the solid solution. Accordingly, the lower limit of the SrO component is 2%, preferably 3%, more preferably 5%, and most preferably 7%, so that the photocatalytic crystal is likely to precipitate, and the concentration of SrTiO ₃ crystal and its solid solution in the glass ceramics. Therefore, desired photocatalytic properties can be ensured. SrO is a component that improves the meltability and stability of the glass, and is also a component that can lower the glass transition temperature and lower the heat treatment temperature. However, when the content of the SrO component exceeds 50%, the stability of the glass is deteriorated, and the precipitation of the photocatalytic crystal becomes difficult. Therefore, the upper limit of the SrO component content is preferably 50%, more preferably 45%, and most preferably 40% with respect to the total amount of glass ceramics having an oxide equivalent composition. The SrO component can be contained in the glass ceramic using, for example, Sr (NO ₃ ) ₃ , SrCO ₃ , SrF ₂ or the like as a raw material.

The SiO ₂ component constitutes a glass network structure and is an essential component that enhances the stability and chemical durability of the glass, and a part of it is a solid solution in SrTiO ₃ and contributes to an improvement in photocatalytic activity. The lower limit of the content of the SiO ₂ component is 10% or more, more preferably 15% or more, and most preferably 20% or more. However, when the content of the SiO ₂ component exceeds 85%, there is a problem that the meltability of the glass is deteriorated and / or phase separation is liable to occur and the photocatalytic crystal is difficult to precipitate. Therefore, the upper limit of the content of the SiO ₂ component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 85%, more preferably 70%, and most preferably 55%. The SiO ₂ component can be contained in the glass ceramic using, for example, SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ or the like as a raw material.

In the glass ceramic of the present invention, the total of SiO ₂ and TiO ₂ preferably does not exceed 85%. If the total amount of these components exceeds 85%, the glass becomes very unstable and tends to be a phase-separated glass, and a desired crystal phase cannot be obtained. The upper limit of the total amount of both components is more preferably 80%, most preferably 75%.

Furthermore, when the ratio of the number of Ti cations to the total number of cations of the alkali metal oxide and / or alkaline earth metal oxide exceeds 1.25, a phase-separated glass tends to be obtained, and a homogeneous SrTiO ₃ glass ceramic can be obtained. It becomes difficult. Therefore, [Ti] / ([R] + [Rn]) is preferably 1.25 or less, and more preferably 1.0 or less. Here, [Ti] is the number of Ti cations, [R] is the total number of alkaline earth metal cations, and [Rn] is the total number of alkali metal cations.

On the other hand, since the photocatalytic crystal is less likely to precipitate when the ratio of the Ti and the components dissolved in substitution at the Ti site is small, [X _Ti ] / [Y _Sr ] is preferably 0.75 or more, more preferably 0.8. 9 or more, most preferably 1.0 or more. Here, [X _Ti ] is the total number of cations of components (one or more selected from Zr, Hf, V, Nb, Ta, Cr, Mn, Fe, Al, Ga, and Mg) that are easily substituted with Ti and Ti sites. , [Y _Sr ] is the total number of cations of components (one or more selected from K, Rb, Ca, Ba, La, Ce) that are easily substituted into Sr and Sr sites. Here, the easily replaceable component is a component in which the Ti site has 6 coordination, and the difference between the Shannon ion radius and the Pauling electronegativity Ti is 20% or less, and the Sr site has 12 coordination. This is a component having a difference between the Shannon ion radius and the Pauling electronegativity Sr within 20%.

The Li 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 lowers the glass transition temperature to lower the heat treatment temperature, thereby precipitating photocatalytic crystals. The Li ⁺ ion is a component that contributes to the improvement of the photocatalytic characteristics by solid solution in the SrTiO ₃ crystal phase, and can be arbitrarily added to the glass ceramic of the present invention. However, if the content of the Li ₂ O component exceeds 40%, the stability of the glass deteriorates and the weather resistance decreases. Therefore, the Li ₂ O component content is preferably 40%, more preferably 35%, and most preferably 30% with respect to the total amount of glass ceramics having an oxide equivalent composition. The Li ₂ O component can be contained in the glass ceramic using, for example, Li ₂ CO ₃ , LiNO ₃ , LiF or the like as a raw material.

The Na 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 heat treatment, and lowers the glass transition temperature to lower the heat treatment temperature, thereby precipitating photocatalytic crystals. And is a component that Na ⁺ ions are dissolved in the SrTiO ₃ crystal phase and contribute to the improvement of the photocatalytic properties, and can be optionally added to the glass ceramics of the present invention. However, when the content of the Na ₂ O component exceeds 40%, the stability of the glass is deteriorated, and the precipitation of the photocatalytic crystal becomes difficult. Therefore, the upper limit of the content of the Na ₂ O component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 40%, more preferably 30%, and most preferably 25%. The Na ₂ O component can be contained in the glass ceramic using, for example, Na ₂ O, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ S, Na ₂ SiF ₆ or the like as a raw material.

The K 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 lowers the glass transition temperature to lower the heat treatment temperature, thereby precipitating photocatalytic crystals. The K ⁺ ion is a component that contributes to the improvement of the photocatalytic properties by solid solution in the SrTiO ₃ crystal phase, and can be optionally added to the glass ceramics of the present invention. However, when the content of the K ₂ O component exceeds 40%, the stability of the glass is deteriorated, and the precipitation of the photocatalytic crystal becomes difficult. Therefore, the upper limit of the content of the K ₂ O component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 40%, more preferably 30%, and most preferably 20%. The K ₂ O component can be contained in the glass ceramic using, for example, K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ or the like as a raw material.

The Rb ₂ O component is a component that improves the meltability and stability of the glass, makes it difficult to crack the glass ceramic after heat treatment, and lowers the glass transition temperature to lower the heat treatment temperature, and Rb ⁺ ion is a component that contributes to the improvement of the photocatalytic properties by solid solution in the SrTiO ₃ crystal phase, and can be optionally added to the glass ceramic of the present invention. However, when the content of the Rb ₂ O component exceeds 10%, the stability of the glass is deteriorated, and the precipitation of the photocatalytic crystal becomes difficult. Therefore, the upper limit of the content of the Rb ₂ O component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 10%, more preferably 8%, and most preferably 5%. The Rb ₂ O component can be contained in the glass ceramic using, for example, Rb ₂ CO ₃ , RbNO ₃ or the like as a raw material.

The Cs 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 heat treatment, and is a component that lowers the glass transition temperature and lowers the heat treatment temperature. It is a component that can be optionally added to the glass ceramics of the invention. However, when the content of the Cs ₂ O component exceeds 10%, the safety of the glass is deteriorated, and the precipitation of the photocatalytic crystal becomes difficult. Therefore, the upper limit of the content of the Cs ₂ O component with respect to the total amount of the glass ceramic material with an oxide conversion composition is preferably 10%, more preferably 8%, and most preferably 5%. The Cs ₂ O component can be contained in the glass ceramic using, for example, Cs ₂ CO ₃ , CsNO ₃ or the like as a raw material.

The total amount of the Rn ₂ O component (wherein Rn is one or more selected from the group consisting of Li, Na, K, Rb, and Cs) is preferably 40% or less. By making the total amount of at least one or more components selected from Rn ₂ O components 40% or less, the stability of the glass can be improved and the weather resistance can be improved. Therefore, the total mass of at least one component selected from the Rn ₂ O components is preferably 40%, more preferably 35%, and most preferably 30% with respect to the total amount of glass ceramics having an oxide equivalent composition. And In the present invention, the Rn ₂ O component is an optional component. However, when these components are contained, the lower limit of the total amount of the Rn ₂ O component is preferably 0.1% in order to exhibit the effect. More preferably, it is 1%, and most preferably 3%.

The BeO component is a component that improves the meltability and stability of the glass and is a component that lowers the glass transition temperature and lowers the heat treatment temperature, and can be optionally added to the glass ceramic of the present invention. However, when the content of the BeO component exceeds 50%, the stability of the glass is deteriorated, and the precipitation of the photocatalytic crystal becomes difficult. Therefore, the upper limit of the content of the BeO component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 50%, more preferably 30%, and most preferably 20%.

The MgO component is a component that improves the meltability and stability of the glass, lowers the glass transition temperature, lowers the heat treatment temperature, promotes the precipitation of photocatalytic crystals, and Mg ²⁺ ions enter the SrTiO ₃ crystal phase. It is a component that contributes to the improvement of photocatalytic properties by solid solution, and is a component that can be arbitrarily added to the glass ceramics of the present invention. However, if the content of the MgO component exceeds 50%, the stability of the glass is deteriorated, and it is difficult to deposit photocatalytic crystals. Accordingly, the upper limit of the content of the MgO component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 50%, more preferably 30%, and most preferably 20%. The MgO component can be contained in the glass ceramic using, for example, MgO, MgCO ₃ , MgF ₂ or the like as a raw material.

The CaO component is a component that improves the meltability and stability of the glass, lowers the glass transition temperature to lower the heat treatment temperature, promotes the precipitation of photocatalytic crystals, and causes Ca ²⁺ ions to enter the SrTiO ₃ crystal phase. It is a component that contributes to the improvement of photocatalytic properties by solid solution, and is a component that can be arbitrarily added to the glass ceramics of the present invention. However, if the content of the CaO component exceeds 50%, the stability of the glass is deteriorated, and the photocatalytic crystals are difficult to precipitate. Therefore, the upper limit of the content of the CaO component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 50%, more preferably 35%, and most preferably 25%. The CaO component can be contained in the glass ceramic using, for example, CaCO ₃ , CaF ₂ or the like as a raw material.

The BaO component is a component that improves the meltability and stability of the glass, lowers the glass transition temperature to lower the heat treatment temperature, promotes the precipitation of photocatalytic crystals, and Ba ²⁺ ions enter the SrTiO ₃ crystal phase. It is a component that contributes to the improvement of photocatalytic properties by solid solution, and is a component that can be arbitrarily added to the glass ceramics of the present invention. However, when the content of the BaO component exceeds 50%, the stability of the glass is deteriorated, and the precipitation of the photocatalytic crystal becomes difficult. Therefore, the upper limit of the content of the BaO component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 50%, more preferably 40%, and most preferably 30%. The BaO component can be contained in the glass ceramic using, for example, BaCO ₃ , Ba (NO ₃ ) ₂ , BaF ₂ or the like as a raw material.

The ZnO component is a component that improves the meltability and stability of the glass, lowers the glass transition temperature to keep the heat treatment temperature lower, promotes the precipitation of photocatalytic crystals, and Zn ²⁺ ions enter the SrTiO ₃ crystal phase. It is a component that contributes to the improvement of photocatalytic properties by solid solution, and is a component that can be arbitrarily added to the glass ceramics of the present invention. However, when the content of the ZnO component exceeds 50%, the glass is liable to be devitrified and the stability of the glass is deteriorated, and the precipitation of the photocatalytic crystal becomes difficult. Therefore, the upper limit of the content of the ZnO component with respect to the total amount of glass ceramics having an oxide conversion composition is preferably 50%, more preferably 40%, and most preferably 30%. The ZnO component can be contained in the glass ceramic using, for example, ZnO, ZnF ₂ or the like as a raw material.

The total amount of the RO component (wherein R is one or more selected from the group consisting of Be, Mg, Ca, Ba, and Zn) precipitates SrTiO ₃ and its solid solution useful for providing photocatalytic performance. Although effective, the stability of the glass is improved and the photocatalytic crystal is easily precipitated by reducing the mass sum of at least one component selected from RO components to 50% or less. Can be secured. Accordingly, the total mass of at least one component selected from RO components is preferably 50%, more preferably 40%, and most preferably 30% with respect to the total amount of glass ceramics having an oxide equivalent composition. . In the present invention, the RO component is an optional component, but when these components are contained, the lower limit of the total amount of the RO component is preferably 0.1%, more preferably 1%, in order to exhibit the effect. Most preferably, it is 3%.

Al ₂ O ₃ component increases 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 SrTiO ₃ crystal phase. It is a component that contributes to the above and can be optionally added. However, when the content exceeds 20%, the melting temperature is remarkably increased and vitrification becomes difficult. Therefore, the upper limit of the content of the Al ₂ O ₃ component with respect to the total amount of glass ceramics having an oxide equivalent composition is preferably 20%, more preferably 15%, and most preferably 10%. The Al ₂ O ₃ component can be contained in the glass ceramic using, for example, Al ₂ O ₃ , Al (OH) ₃ , AlF ₃ or the like as a raw material.

The ZrO ₂ component is a component that enhances chemical durability, promotes the precipitation of photocatalytic crystals, and contributes to the improvement of photocatalytic properties by solid solution of Zr ⁴⁺ ions in the SrTiO ₃ crystal phase. It is. However, if the content of the ZrO ₂ component exceeds 10%, vitrification becomes difficult. Therefore, the upper limit of the content of the ZrO ₂ component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 10%, more preferably 7%, and most preferably 5%. The ZrO ₂ component can be contained in the glass ceramic using, for example, ZrO ₂ , ZrF ₄ or the like as a raw material.

Nb ₂ O ₅ component is a component that enhances the meltability and stability of glass, promotes the precipitation of photocatalytic crystals, and contributes to the improvement of photocatalytic properties by solid solution of Nb ⁵⁺ ions in the SrTiO ₃ crystal phase. It is a component that can be optionally added to the glass ceramics of the present invention. However, when the content of the Nb ₂ O ₅ component exceeds 25%, the stability of the glass is remarkably deteriorated. Therefore, the content of the Nb ₂ O ₅ component is preferably 25%, more preferably 20%, and most preferably 15% with respect to the total amount of glass ceramics having an oxide equivalent composition. The Nb ₂ O ₅ component can be contained in the glass ceramic using, for example, Nb ₂ O ₅ as a raw material.

The Ta ₂ O ₅ component is a component that enhances the stability of the glass, promotes the precipitation of the photocatalytic crystal, and contributes to the improvement of the photocatalytic property by dissolving Ta ⁵⁺ ions in the SrTiO ₃ crystal phase, It is a component that can be optionally added. However, when the content of the Ta ₂ O ₅ component exceeds 20%, the stability of the glass is remarkably deteriorated. Therefore, the content of the Ta ₂ O ₅ component is preferably 20%, more preferably 15%, and most preferably 10% with respect to the total amount of glass ceramics having an oxide equivalent composition. The Ta ₂ O ₅ component can be contained in the glass ceramic using, for example, Ta ₂ O ₅ as a raw material.

The total amount of at least one component selected from Nb ₂ O ₅ component and Ta ₂ O ₅ component is preferably 25% or less. When it is more than this, the stability of the glass ceramics is deteriorated, and it becomes impossible to form good glass ceramics. More preferably, the upper limit is 20%, and most preferably 15%. In addition, although it is possible to obtain glass ceramics having high photocatalytic properties even if neither Nb ₂ O ₅ component nor Ta ₂ O ₅ component is contained, the photocatalytic properties can be further improved.

As ₂ O ₃ component and Sb ₂ O ₃ component are components for clarifying and defoaming glass ceramics, and when added together with Ag, Au, and Pt ions, which will be described later, and have the effect of enhancing photocatalytic activity, Since it plays the role of a reducing agent, it is a component that indirectly contributes to improving the activity of the photocatalyst and can be added arbitrarily. However, when the content of these components exceeds 5.0% in total, the stability of the glass is deteriorated, and the photocatalytic properties are liable to deteriorate. Therefore, the total content of As ₂ O ₃ component and / or Sb ₂ O ₃ component with respect to the total amount of glass ceramics in oxide equivalent composition is preferably 5.0%, more preferably 3.0%, most preferably The upper limit is 1.0%. 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. It can be used and contained in glass ceramics.

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

In addition to the above components, other components can be added to the glass ceramics of the present invention as needed within a range not impairing the properties of the glass ceramics.

The Ga ₂ O ₃ component enhances the stability of the glass and the chemical durability of the glass ceramic, promotes the precipitation of photocatalytic crystals from the glass, and improves the photocatalytic properties by dissolving Ga ³⁺ ions in the SrTiO ₃ crystal phase. It is a component that contributes to the above and can be optionally added. However, when the content exceeds 20%, the melting temperature is remarkably increased and vitrification becomes difficult. Therefore, the content of the Gd ₂ O ₃ component is preferably 20%, more preferably 15%, and most preferably 10% with respect to the total amount of glass ceramics having an oxide equivalent composition. The Ga ₂ O ₃ component can be contained in the glass ceramic using, for example, Ga ₂ O ₃ as a raw material.

The HfO ₂ component is a component that enhances chemical durability, promotes the precipitation of photocatalytic crystals, and contributes to the improvement of photocatalytic properties by Hf ⁴⁺ ions dissolving in the SrTiO ₃ crystal phase. It is. However, when the content of the HfO ₂ component exceeds 10%, vitrification becomes difficult. Therefore, the upper limit of the content of the HfO ₂ component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 10%, more preferably 7%, and most preferably 5%. The HfO ₂ component can be contained in the glass ceramic using, for example, HfO ₂ as a raw material.

The WO ₃ component is a component that improves the meltability and stability of the glass, and is a component that improves photocatalytic properties when present in the vicinity of the photocatalytic crystal, and can be optionally added. However, if the content of these components exceeds 10%, the stability of the glass is deteriorated, and the photocatalytic properties are liable to deteriorate. Accordingly, the upper limit of the content of the WO ₃ component with respect to the total amount of the glass ceramic material having an oxide equivalent composition is preferably 10%, more preferably 8%, and most preferably 5%. The WO ₃ component can be contained in the glass ceramic using, for example, WO ₃ as a raw material.

The SnO component is a component that promotes the precipitation of the photocatalytic crystal and is effective in improving the photocatalytic properties. In addition, the SnO component is a reducing agent when added together with the below-described Ag, Au, or Pt ions that have an action of enhancing the photocatalytic activity. Is a component that contributes to the activity of the photocatalyst indirectly and can be added arbitrarily. However, if the content of these components exceeds 10%, the stability of the glass is deteriorated, and the photocatalytic properties are liable to deteriorate. Therefore, the upper limit of the SnO component content is preferably 10%, more preferably 8%, and most preferably 5% with respect to the total amount of glass ceramics having an oxide equivalent composition. The SnO component can be contained in the glass ceramic using, for example, SnO, SnO ₂ , SnO ₃ or the like as a raw material.

The B ₂ O ₃ component is a component that constitutes a glass network structure and improves the stability of the glass ceramic, and can be optionally added. However, when the content exceeds 30%, the tendency for the photocatalytic crystals to hardly precipitate is increased. Therefore, the upper limit of the content of the B ₂ O ₃ component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 30%, more preferably 20%, and most preferably 10%. The B ₂ O ₃ component can be contained in the glass ceramic using, for example, H ₃ BO ₃ , Na ₂ B ₄ O ₇ , Na ₂ B ₄ O ₇ .10H ₂ O, BPO ₄ or the like as a raw material.

The GeO ₂ component is a component having a function similar to that of the above-described SiO ₂ and contributes to the stability of the molten glass. Although it is an optional component that can be added to adjust the refractive index and viscosity of the mother glass member, it is a rare mineral resource and is expensive, so it preferably does not exceed 10%, more preferably 5% or less, most preferably none Does not contain.

The TeO ₂ component is a component that increases the meltability and stability of glass, and is a component that lowers the glass transition temperature (Tg) to lower the heat treatment temperature, and can be optionally added. However, when the content of the TeO ₂ component exceeds 20%, the stability of the glass is deteriorated, and the photocatalytic crystal is hardly precipitated. Accordingly, the content of the TeO ₂ component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 20%, more preferably 15%, and most preferably 10%. The TeO ₂ component can be contained in the glass ceramic using, for example, TeO ₂ as a raw material.

The Ln ₂ O ₃ component (wherein Ln is one or more selected from the group consisting of Sc, Y, La, Ce, Nd, Sm, Eu, Gd, Dy, Yb and Lu) is a chemical compound of glass ceramics. It is a component that enhances durability, is a component that improves the photocatalytic properties by being present in the vicinity of the photocatalytic crystal, and can be optionally added. In particular, La ³⁺ ions, Ce ³⁺ ions, and Eu ²⁺ ions (generated by melting conditions) are components that contribute to the improvement of the photocatalytic characteristics by being dissolved in the SrTiO ₃ crystal phase. However, when the total content of the Ln ₂ O ₃ components exceeds 20%, the stability of the glass is remarkably deteriorated. Therefore, the mass sum of at least one component selected from the Ln ₂ O ₃ components is preferably 20%, more preferably 15%, and most preferably 10% with respect to the total amount of glass ceramics in oxide equivalent composition. The upper limit. The Ln ₂ O ₃ component includes, for example, Sc ₂ O ₃ , Y ₂ O ₃ , YF ₃ , La ₂ O ₃ , La (NO ₃ ) ₃ .XH ₂ O (X is an arbitrary integer), CeO ₂ , Nd ₂ O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , GdF ₃ , Dy ₂ O ₃ , Yb ₂ O ₃ , Lu ₂ O _{3 and the} like can be contained in the glass ceramic.

M _x O _y component (wherein M is one or more selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni, and x and y are each x: y = 2: (valence of M The minimum natural number satisfying the number) is dissolved in the SrTiO ₃ crystal phase or is present in the vicinity of the photocatalytic crystal, thereby contributing to the improvement of the photocatalytic properties. Further, it is a component that absorbs visible light of some wavelengths and imparts an appearance color to the glass ceramic, and is an optional component in the glass ceramic of the present invention. In particular, by making the mass sum of at least one component selected from M _x O _y components 10% or less, the stability of the glass ceramic can be improved and the color of the appearance of the glass ceramic can be easily adjusted. . Therefore, the mass sum of at least one component selected from the M _x O _y components is preferably 10%, more preferably 8%, and most preferably 5% with respect to the total amount of the glass ceramics having an oxide equivalent composition. The upper limit. Various oxides, chlorides, sulfides, etc. can be used to be contained in the glass ceramic.

The Bi ₂ O ₃ component is a component that enhances the meltability and stability of the glass, the heat treatment temperature is lowered by lowering the glass transition temperature (Tg), and Bi ³⁺ ions are dissolved in the SrTiO ₃ crystal phase. It is a component that contributes to the improvement of the photocatalytic properties and can be optionally added. However, when the content of the Bi ₂ O ₃ component exceeds 20%, the stability of the glass is deteriorated, and the photocatalytic crystal is hardly precipitated. Therefore, the upper limit of the content of the Bi ₂ O ₃ component with respect to the total amount of the glass ceramic material having an oxide conversion composition is preferably 20%, more preferably 15%, and most preferably 10%. The Bi ₂ O ₃ component can be contained in the glass ceramic using, for example, Bi ₂ O ₃ as a raw material.

The PbO and CdO components are components that enhance the meltability and stability of the glass, the heat treatment temperature is lowered by lowering the glass transition temperature (Tg), and the Pb ²⁺ and Cd ²⁺ ions are dissolved in the SrTiO ₃ crystal phase. Thus, it is a component that contributes to the improvement of the photocatalytic properties and can be optionally added. However, PbO and CdO tend to refrain from use as harmful chemical substances in recent years, and it is preferable not to substantially contain them.

The glass ceramic of the present invention 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 photocatalytic properties by being present in the vicinity of the photocatalytic crystal, and can be optionally added. However, when the content of these components exceeds 10% in total, the stability of the glass is remarkably deteriorated, and the photocatalytic properties are liable to deteriorate. Therefore, in order to ensure good characteristics, the total content of the nonmetallic element component with respect to the total mass of the glass ceramic of the oxide conversion composition is preferably 10%, more preferably 5%, and most preferably 3%. And These non-metallic element components are preferably introduced into the glass ceramic in the form of alkali metal or alkaline earth metal fluoride, chloride, bromide, sulfide, nitride, carbide or the like. The raw material of the nonmetallic element component is not particularly limited, but AlN ₃ , SiN ₄ or the like as the N component raw material, NaS, Fe ₂ S ₃ , CaS ₂ or the like as the S component raw material, ZrF ₄ or AlF ₃ as the F component raw material , NaF, CaF ₂ , SrF _2, etc., contained in glass ceramics by using NaCl, AgCl, etc. as Cl component raw materials, NaBr as Br component raw materials, TiC, SiC, ZrC, etc. as C component raw materials be able to. In addition, these raw materials may be added integrally or may be added independently.

The glass ceramic of the present invention may contain at least one metal component selected from Cu, Ag, Au, Pd, Pt, Ru, and Rh. Since these metal components are present in the vicinity of the crystal phase and have an effect of improving the photocatalytic activity, they can be arbitrarily added. Further, Cu is dissolved in the SrTiO ₃ crystal and has the effect of increasing the photocatalytic activity. However, if the total content of these metal components exceeds 5%, the stability of the glass is remarkably deteriorated, and good glass ceramics cannot be obtained. Accordingly, the total content of the metal components with respect to the total mass of the glass ceramic having an oxide conversion composition is preferably 5%, more preferably 3%, and most preferably 1%. These metal element components can be introduced into glass ceramics using, for example, Ag ₂ O, AuCl ₃ , PtCl ₄ or the like as a raw material. Note that the content of the metal component in this specification is based on the assumption that all the cation components constituting the glass ceramic are made of an oxide combined with oxygen that balances the charge, and the entire glass made of these oxides. The mass is 100%, and the mass of the metal element component is expressed in mass% (extra divided mass% with respect to the oxide-based mass).

Since the composition of the glass ceramic of the present invention is expressed in mol% with respect to the total amount of the oxide-converted composition, it cannot be expressed directly in mass%. However, the composition expressed by mass% of each component present in the composition satisfying various properties required in the present invention generally takes the following values in terms of oxide.
TiO ₂ component 5-50% by mass
SrO component 4 to 70% by mass and / or SiO ₂ component 15 to 70% by mass
Li ₂ O component 0-20% by mass and / or Na ₂ O component 0-25% by mass and / or K ₂ O component 0-35% by mass and / or Rb ₂ O component 0-40% by mass and / or Cs ₂ O component 0-45 mass% and / or BeO component 0-20 mass% and / or MgO component 0-25 mass% and / or CaO component 0-30 mass% and / or BaO component 0-50 mass% and / or ZnO component 0-25% by mass and / or Al ₂ O ₃ component 0-20% by mass and / or ZrO ₂ component 0-15% by mass and / or Nb ₂ O ₅ component 0-40% by mass and / or Ta ₂ O ₅ components 0-40% by weight and / or As ₂ O ₃ component and / or _Sb 2 _{O 3} component in total 0-3% by weight

The glass ceramic of the present invention preferably exhibits catalytic 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 glass ceramics is irradiated with light of wavelengths from the ultraviolet region to the visible region, the catalytic activity is expressed, so that dirt substances and bacteria attached to the surface of the glass ceramics are decomposed by oxidation or reduction reaction. Therefore, glass ceramics can be used for antifouling applications, antibacterial applications, purification applications such as water quality, and the like. In the present invention, other ions are dissolved in the crystal phase of strontium titanate during the production of the glass ceramic, and the band gap energy of strontium titanate becomes small. Obtainable. Here, the catalytic activity of the glass ceramic of the present invention is set to 3.0 nmol / l / min or more when expressed by a decomposition activity index. Here, the decomposition activity index of the glass ceramics of the present invention can be obtained based on Japanese Industrial Standard JIS R1703-2: 2007.

The glass ceramic of the present invention can be used as a photocatalytic functional glass ceramic member for various machines, devices, instruments and the like. In particular, it is preferably used for applications such as tiles, window frames, building materials, and home appliances that require antifouling and antifogging functions. The glass ceramics of the present invention are excellent in moldability and the material itself has a photocatalytic function, so that it can be used in any shape without worrying about deterioration of characteristics. For example, it can be used as a purification filter or a deodorizing filter in the form of beads or fibers. It is also possible to form a glaze layer having photocatalytic properties by using a powdered material as a glaze raw material.

Next, the manufacturing method of the glass ceramic of this invention is demonstrated.

<First Embodiment>
1st Embodiment of the manufacturing method of the glass ceramics of this invention is a manufacturing method of the glass ceramics characterized by melt | dissolving a raw material composition mixture, obtaining the melt, and cooling and solidifying after that. This technique is effective, for example, when a desired crystal phase is richly precipitated and the state of the glass melt is relatively unstable. More specifically, a predetermined starting material is uniformly mixed, put into a container made of platinum or refractory, and heated and held at a predetermined temperature of 1200 ° C. to 1600 ° C. in an electric furnace to produce a melt. To do. Thereafter, the melt is poured into a mold and solidified to obtain a target crystallized glass. Here, the melting temperature is preferably changed as appropriate depending on the type and amount of the composition to be mixed. Examples of the refractory container include quartz glass, alumina, magnesia, zirconia, and a skull pot, but are not particularly limited.

Here, generation and growth of crystal nuclei occur in the process of cooling the melt. While controlling the cooling rate of the melt, it is poured into a mold and cooled to a crystallization temperature region where crystal nucleus formation and growth occur (first cooling step). Crystals are deposited on the glass after reaching the crystallization temperature region. By controlling the temperature of the region, the residence time in the temperature region, the cooling rate in the temperature region, etc., the target crystal The type, size and amount of crystal phase can be controlled (crystallization step). The crystallization temperature region may pass at a constant cooling rate, or may be maintained at a specific temperature for a certain time. Since the cooling speed and temperature greatly affect the formation of crystal phase and the crystal size, it is very important to control them precisely. When a desired crystal is obtained, it is cooled to a temperature outside the range of the crystallization temperature region to obtain a glass ceramic in which the crystal is dispersed (second cooling step).

Second Embodiment
The second embodiment of the glass ceramic manufacturing method of the present invention includes a melting step of mixing raw materials to obtain a melt, a cooling step of cooling the melt to obtain a glass body, and a temperature of the glass body. A reheating step for raising the temperature to a temperature range exceeding the glass transition temperature, a crystallization step for maintaining the temperature in the temperature range to produce crystals, and a recooling step for reducing the temperature again to obtain a crystal-dispersed glass. It is a manufacturing method of the glass ceramic which has.

(Melting process)
The melting step is a step of obtaining a melt by mixing raw materials having the above-described composition. More specifically, the raw materials are prepared so that each component of the glass ceramic is within a predetermined content range, uniformly mixed, and the prepared mixture is put into a platinum crucible, a quartz crucible or an alumina crucible, and electric Melt in a furnace at a temperature range of 1200 to 1600 ° C. for 1 to 24 hours, and homogenize with stirring to prepare a melt. In addition, 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 amount of the raw material composition.

(Cooling process)
A cooling process is a process of producing a glass body by cooling and vitrifying the melt obtained at the melting process. 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.

(Crystallization process)
The crystallization process is a process in which the temperature of the glass body is raised to a temperature region exceeding the glass transition temperature and held at that temperature for a predetermined time. By holding for a predetermined time in a predetermined temperature range in this crystallization step, strontium titanate having a desired size from nano to micron and / or its solid solution crystal can be uniformly dispersed inside the glass body. Thus, glass ceramics having photocatalytic activity can be more reliably produced.

Although it is necessary to set a crystallization temperature according to a glass transition temperature for every glass composition in said crystallization process, it is preferable to heat-process in a temperature range specifically 10 degreeC or more higher than a glass transition temperature. As for the glass of this invention, the minimum of the preferable heat processing temperature (crystallization temperature) is 580 degreeC, More preferably, it is 600 degreeC, Most preferably, it is 650 degreeC. On the other hand, if the heat treatment temperature becomes too high, the tendency of the strontium titanate crystal phase to decrease becomes strong and the photocatalytic properties tend to disappear, so the upper limit of the heat treatment temperature is preferably 1100 ° C, more preferably 1050 ° C, more preferably 1000 ° C. Is most preferred. This temperature range is also applied to the crystallization temperature region that is passed or maintained when the glass ceramic is produced in the first embodiment.

The crystallization atmosphere need not be particularly controlled, but may be oxidizing, inert, or reducing. By controlling the atmosphere, defects can be introduced into the strontium titanate crystal and the photocatalytic activity can be enhanced. For example, in the reducibility, it is an oxygen defect represented by SrTiO _3-x .

(Etching process)
The glass body after crystals are formed by performing the crystallization process can exhibit high photocatalytic properties as glass ceramics as it is, but the crystal phase is obtained by performing an etching process on the glass ceramics. By removing the glass phase around and increasing the specific surface area of the crystal phase exposed on the surface, it is possible to further enhance the photocatalytic properties of the glass ceramic. Moreover, it is possible to obtain a porous body in which only the photocatalytic crystal phase remains by controlling the solution used in the etching step and the etching time. Here, examples of the etching step include dry etching and / or immersion in a solution. 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.

[photocatalyst]
The glass ceramic 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 the effect | action which decomposes | disassembles organic substance with light, such as an ultraviolet-ray and visible light. This photocatalyst can be used as, for example, a photocatalyst material, a photocatalyst member (for example, a water purification material, an air purification material, etc.), and the like.

[Glass ceramic compact]
The glass ceramic molded body thus produced is useful as a photocatalytic functional glass ceramic molded body for various machines, devices, instruments, water purification, etc., and in particular, tiles, window frames, building materials, and filtration. It is preferably used for applications such as materials. Thereby, since the photocatalytic function is exhibited on the surface of the glass ceramic molded body and the fungi attached to the surface of the glass ceramic molded body are sterilized, the surface can be kept hygienic when used in these applications.

Since the glass ceramic of the present invention does not have a film or a coating layer and exhibits photocatalytic properties as a single unit, there is no deterioration of catalytic activity due to peeling, and it eliminates the trouble of replacement and maintenance, and is suitably used for, for example, a filter and a purification device. . For example, the glass ceramic molded body of the present invention can be processed into various forms depending on the application. In particular, by adopting, for example, the form of beads or fibers (glass fibers), the exposed area of the strontium titanate crystal phase increases, so that the photocatalytic activity of the glass ceramic molded body can be further increased. In many cases, the filter member and the purification device using the photocatalytic function have a configuration in which the photocatalytic material is adjacent to a member serving as a light source in the device. However, if the shape is a bead or a fiber, it can be easily placed in a container in the device. Since it is stored, it can be suitably used.

Hereinafter, as a typical embodiment of the glass ceramics of the present invention, glass ceramic fibers, powder particles, a slurry-like mixture, a glass ceramic sintered body, a glass ceramic composite, and the like will be described as examples.

[Glass granules]
The glass powder according to the present invention contains a crystal phase containing a photocatalytic crystal having photocatalytic properties in the glass, or can be heated to produce the crystal phase in the glass. This crystalline phase exists or is uniformly dispersed in and inside the amorphous glass constituting the glass powder. The glass powder particles can also be used in the production of glass ceramic sintered bodies and glass ceramic composites described later.

When the “glass powder” includes crystals, the glass powder has photocatalytic properties. Such glass powder particles are crushed after crystallization of the glass body obtained from the raw material composition, or after crystallization by heat treatment of the glass body obtained from the raw material composition Is obtained. In the present specification, the glass powder including the crystal as described above may be referred to as “glass ceramic powder”. On the other hand, when the “glass powder” does not contain a crystal phase, the glass powder does not have photocatalytic properties, and the crystal phase can be precipitated by heating the glass powder. In this specification, glass powder particles that can generate crystals having photocatalytic properties by heat treatment are sometimes referred to as “uncrystallized glass powder particles”. When it is simply referred to as a glass powder, it is used to include both “glass ceramic powder” and “uncrystallized glass powder”.

Next, the manufacturing method of the glass-ceramics granular material and uncrystallized glass granular material of this invention is demonstrated separately. In addition, the manufacturing method of the glass granular material of this invention can include arbitrary processes other than the process demonstrated below.

(1) Manufacturing method of glass ceramic powder The glass ceramic powder is not particularly limited, but can be manufactured by the following two methods as examples.

Manufacturing method A1:
In this production method A1, a raw material composition is melted and vitrified to produce a glass body, a glass body is subjected to a heat treatment, and a glass ceramic is produced, and the glass ceramic is pulverized. And a pulverizing step for producing glass ceramic powder particles.

(Vitrification process)
In the vitrification step, a predetermined raw material composition is melted, solidified, and vitrified to produce a glass body. The vitrification step can be performed in accordance with the melting step and the cooling step in the above typical production examples. Note that the vitrification process can be performed by the floating zone melting method or the like, and the container is not necessarily used.

(Crystallization process)
In the crystallization process, the glass body is subjected to heat treatment to produce glass ceramics. Since the crystal phase containing the photocatalytic crystal is precipitated inside and on the surface of the glass body by the crystallization step, the crystal phase containing the photocatalytic crystal can be surely included in the glass powder later. The heat treatment conditions (temperature, time) can be appropriately set according to the composition of the glass body, the required degree of crystallization, and the like. The crystallization step can be carried out under the same conditions as in the above representative production examples.

(Crushing process)
In the pulverization step, the glass ceramics are pulverized to produce glass ceramic powder particles. The method for pulverizing the glass ceramic 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.

Production method A2:
Production method A2 includes a vitrification step for producing a glass body by melting and vitrifying the raw material composition, a pulverization step for crushing the glass body to produce an uncrystallized glass powder, and uncrystallization A crystallization step of subjecting the glass powder to a heat treatment to produce a glass ceramic powder.

(Vitrification process)
A vitrification process produces a glass body by fuse | melting and vitrifying a raw material composition. This vitrification step can be performed in accordance with the melting step and the cooling step of the above representative production method, similarly to the vitrification step of production method A1.

(Crushing process)
In the pulverization step, the glass body is pulverized to produce an uncrystallized glass powder. This pulverization step can be performed in the same manner as the pulverization step in the production method A1, except that an uncrystallized glass body is pulverized to produce an uncrystallized glass powder.

(Crystallization process)
In the crystallization step, the non-crystallized glass particles are heat treated to produce glass ceramic particles. Through the crystallization step, a crystal phase containing photocatalytic crystals is precipitated inside and on the surface of the glass ceramic. The heat treatment conditions (temperature, time) in this crystallization step can be carried out in the same manner as in the crystallization step in production method A1, except that the heat treatment is performed on the uncrystallized glass powder instead of the glass body.

(2) Production method of uncrystallized glass powder production method A3:
The method for producing the uncrystallized glass particles is not particularly limited, but the raw material composition is melted and vitrified to produce a vitrification step for producing a glass body, And a pulverizing step for producing crystallized glass particles. That is, it can carry out similarly to the said manufacturing method A2 except remove | excluding the crystallization process in manufacturing method A2 of a glass ceramic granular material. Thereby, although it does not contain the crystal | crystallization which has a photocatalytic characteristic, the non-crystallized glass powder body which can produce | generate this crystal | crystallization by subsequent heating can be manufactured.

In addition, the method of the heat processing at the time of heating a non-crystallized glass granular material and producing | generating a crystal | crystallization can be implemented similarly to the said crystallization process demonstrated with the manufacturing method of the glass ceramic granular material. However, when it is carried on an arbitrary base material, it is preferable to adjust the heat treatment temperature according to the heat-resistant temperature of the base material.

(Addition process)
Manufacturing method A1-A3 of this invention can include the addition process which increases the said component by mixing arbitrary components with a glass granular material. This step is preferably performed after the pulverization step in the production methods A1 to A3, and most preferably performed before the heat treatment (crystallization step) in the production method A2 in which heat treatment (crystallization step) is performed later. There are no particular restrictions on the components added to the glass granules in the addition process, but there are components that can enhance the function of the components by increasing the amount at the glass powder stage, and melting because vitrification becomes difficult It is preferable to mix components that can be blended only in a small amount into the glass raw material composition. In addition, in this specification, the state after mixing another component with a glass granular material at this process may be named generically as a "powder particle mixture." In the case where the addition step is performed, in each step performed after the addition step, the “glass powder” in the case where the addition step is not performed can be performed in the same manner, except that the “particle mixture” is replaced.

(Addition of photocatalytic crystals)
In the production methods A1 to A3 of the present invention, addition of crystals having photocatalytic activity (photocatalytic crystals) such as TiO ₂ crystals, WO ₃ crystals, and ZnO crystals in a crystalline state is added to glass particles to produce a powder mixture You may have a process. In the method of the present invention, a crystal phase containing photocatalytic crystals can be produced from a glass body without mixing photocatalytic crystals. However, by adding a photocatalytic crystal in a crystalline state to the glass powder, it is possible to increase the amount of the crystal, to contain abundant photocatalytic crystal, and to produce a glass powder having an enhanced photocatalytic function.

The mixing amount of the photocatalytic crystal can be appropriately set so that a desired amount of the photocatalytic crystal is present in the material using the glass powder according to the composition of the glass body, the temperature in the production process, and the like. When the crystal is mixed in order to impart the photocatalytic function of a specific crystal to the glass powder of the present invention, the lower limit of the amount of the photocatalytic crystal in the crystalline state is required to express the effect of the added component. Is preferably 1%, more preferably 5%, and most preferably 10% by mass ratio to the powder mixture. On the other hand, the upper limit of the amount of photocatalytic crystals in the mixed crystalline state is preferably 95%, more preferably 80%, and most preferably 60% in terms of mass ratio to the powder mixture. In addition, when mixing a plurality of types of photocatalytic crystals, the total amount is preferably within the range of the above upper limit value and lower limit value.

The raw material particle size of the photocatalytic crystal added to the glass powder is preferably as small as possible from the viewpoint of enhancing the photocatalytic activity. However, if the raw material particle size is too small, it reacts with the glass during the heat treatment, and the crystal state cannot be maintained and may disappear. Moreover, when the raw material particles are too fine, there is a problem that handling in the manufacturing process becomes difficult. On the other hand, if the raw material particle size is too large, it tends to remain in the final product in the form of raw material particles, and the tendency to hardly obtain desired photocatalytic properties becomes strong. Accordingly, the size of the raw material particles is preferably in the range of 11 to 500 nm, more preferably in the range of 21 to 200 nm, and most preferably in the range of 31 to 100 nm.

(Addition of non-metallic element components)
In the production methods A1 to A3 of the present invention, an additive containing at least one selected from the group consisting of an N component, an S component, an F component, a Cl component, a Br component, and a C component is used as the glass powder or You may have the addition process added to a granular mixture. These non-metallic element components can be blended as part of the components of the raw material composition at the stage of making a batch or cullet before producing the glass body as described above. However, it is easier to introduce these non-metallic element components into the glass powder after producing the glass body, and it is easier to introduce and more effectively exert its functions. It becomes possible to easily obtain glass powder particles having characteristics.

When a nonmetallic element component is added, the mixing amount can be appropriately set according to the composition of the glass body. From the viewpoint of sufficiently improving the photocatalytic function of the glass particles, the total of the nonmetallic components is preferably 0.01% or more, more preferably 0.05%, in terms of mass ratio to the crushed glass body or its particle mixture. As mentioned above, it is most effective to add 0.1% or more. On the other hand, when added excessively, the photocatalytic properties tend to be reduced, so the upper limit of the mixing amount is preferably 20.0% by mass ratio to the crushed glass or its particle mixture as the sum of the nonmetallic components, More preferably, it is 10.0%, and most preferably 5.0%.

As the raw material to be added is a nonmetallic element component is not particularly limited, N component _AlN 3, SiN _4, etc., S component _{NaS, Fe 2 S 3, CaS} 2 etc., F component _ZrF 4, AlF ₃ , NaF, CaF _2, etc., Cl component NaCl, AgCl or the like, Br component NaBr etc., C may be used as component C, TiC, SiC or ZrC and the like. In addition, the raw materials of these nonmetallic element components may be added in combination of two or more, or may be added alone.

(Addition of metal element components)
The production methods A1 to A3 of the present invention include an addition step of adding a metal element component composed of one or more selected from the group consisting of Cu, Ag, Au, Pd, Re, and Pt to the glass powder or powder mixture. You may have. These metal element components can be blended as part of the components of the raw material composition at the stage of making a batch or cullet before producing the glass body as described above. However, it is easier to introduce these metal element components into the glass powder after making the glass body, and it is easier to introduce and more effectively exert its functions. It becomes possible to easily obtain a glass powder body having. In the case of adding a metal element component, the mixing amount can be appropriately set according to the composition of the glass body. From the viewpoint of sufficiently improving the photocatalytic function of the glass particles, the total of the metal element components is preferably 0.001% or more, more preferably 0.005%, in terms of the mass ratio with respect to the crushed glass body or its particle mixture. As described above, it is most effective to add 0.01% or more. On the other hand, if added excessively, the photocatalytic properties are liable to deteriorate, so the upper limit of the mixing amount is preferably 10% by mass ratio to the crushed glass or its powder mixture as the total of the metal element components, more preferably Is 5%, most preferably 3%. Incidentally, as a raw material in the case of adding a metal element component is not particularly limited, for example _{CuO, Cu 2 O, Ag 2} O, can be used _{AuCl 3, PtCl 4, H 2} PtCl 6, PdCl 2 and the like. In addition, the raw materials for these metal element components may be added in combination of two or more, or may be added alone.

The particle size and shape of the metal element component as an additive can be appropriately set according to the composition of the glass body, the amount of the photocatalytic crystal, the crystal type, etc., but the photocatalytic function of the glass particle is maximized. For this, the average particle size of the metal element component should be as small as possible. Therefore, the upper limit of the average particle diameter of the metal element component is preferably 5.0 μm, more preferably 1.0 μm, and most preferably 0.1 μm.

(Surface treatment process)
Manufacturing method A1-A3 of this invention may further have the process (surface treatment process) which performs surface treatments, such as an etching, to the glass granular material obtained as mentioned above. This step is particularly preferably performed on the glass ceramic powder obtained by the production methods A1 and A2. Etching can be performed, for example, by immersing the glass powder in an acidic or alkaline solution. If it does in this way, a glass phase can melt | dissolve and the surface of a glass granular material can be made into an uneven | corrugated state, or can be made into a porous state. As a result, the exposed area of the crystal phase containing the photocatalytic crystal is increased, so that higher photocatalytic activity can be obtained. The acidic or alkaline solution used for the immersion is not particularly limited as long as it can corrode glass phases other than the crystal phase including the photocatalytic crystals of the glass particles, and for example, an acid (fluorine) containing fluorine or chlorine. Hydrofluoric acid, hydrochloric acid, etc.) can be used.

Further, as another etching method, etching may be performed by spraying hydrogen fluoride gas, hydrogen chloride gas, hydrofluoric acid, hydrochloric acid, or the like on the surface of the glass particles.

[Glass ceramic fiber]
The glass ceramic 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.

There are curtains, sheets, wall-clothing cloths, insect screens, clothes, or heat insulating materials, etc. as applications that make use of heat resistance and nonflammability of glass fibers. The article can be given a deodorizing function, a dirt decomposing function, etc. by photocatalytic action, and the labor of cleaning and maintenance can be greatly reduced.

In addition, glass fiber is often used as a filtering material because of its chemical resistance, but the glass ceramic fiber of the present invention is not only filtered, but also a malodorous substance, dirt, bacteria, etc. in the object to be treated by a photocatalytic reaction. Therefore, it is possible to provide a purification device and a filter having a more active purification function. 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 ceramic fiber of this invention is demonstrated. The method for producing glass ceramic fibers of the present invention includes a melting step of mixing raw materials to obtain a melt thereof, a spinning step of forming into a fiber shape using the melt or glass obtained from the melt, and the temperature of the fibers. May be included in a temperature range exceeding the glass transition temperature, and held at that temperature for a predetermined time to precipitate a desired crystal. In addition, since the general manufacturing method of the glass ceramic demonstrated as the said typical manufacturing method example is applicable to this specific example in the range which is not inconsistent, they are used suitably and the overlapping description is abbreviate | omitted.

(Melting process)
It can be carried out in the same manner as in the above representative production method example.

(Spinning process)
Next, it shape | molds from the melt obtained at the melting process to glass fiber. The forming method of the fiber body is not particularly limited, and can be formed using a known method. However, according to the above-described typical production method, for example, the forming may be performed simultaneously with rapid cooling by a blowing method, a spinning method, or the like. Is preferred. In addition, when forming into a fiber (long fiber) of a type that can be continuously wound on a winder, it may be spun by a known DM method (direct melt method) or MM method (marble melt method). When forming into short fibers of about 10 cm, a centrifugal method may be used, or the long fibers may be cut. 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. Thereafter, it can be made into a cotton shape or a fiber structure such as roving or cloth according to the application.

(Crystallization process)
Next, the fiber or the fiber structure obtained by the above process is reheated to perform a crystallization step for depositing desired crystals in and on the fiber. The crystallization step can be carried out under the same conditions as in the above representative production examples. When a desired crystal is obtained, the glass ceramic fiber or the fiber structure in which the photocatalytic crystal is dispersed can be obtained by cooling to outside the crystallization temperature region.

In addition to the method of crystallizing after forming the fiber body as described above, the temperature of the glass fiber in the spinning process may be controlled so that the crystallization process is performed simultaneously.

The glass ceramic fiber after the crystallization process has produced crystals can exhibit high photocatalytic properties even if it remains as it is. However, by performing an etching process on this glass ceramic fiber, Since the surrounding glass phase is removed and the specific surface area of the crystal phase exposed on the surface is increased, the photocatalytic properties of the glass ceramic 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. The etching process can be carried out in the same manner as the above representative production method.

[Slurry mixture]
A slurry mixture can be prepared by mixing the glass particles (glass ceramic particles and non-crystallized glass particles) of the present invention obtained as described above 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 a solvent and / or an inorganic or organic binder to the glass powder.

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. These can be used alone or in combination of two or more.

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 These may be used alone or in combination of two or more.

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. Specifically, for example, acrylic resin, ethyl cellulose, polyvinyl butyral, methacrylic resin, urethane resin, butyl methacrylate, vinyl copolymer and the like may be used, and these may be used alone or in combination of two or more. it can.

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-like mixture of the present invention can be produced by dispersing glass powder particles in a solvent. That is, the manufacturing method of the slurry-like mixture of the present invention can be performed by any of the following manufacturing methods B1 to B3. In addition, the manufacturing method of the slurry-like mixture of this invention can include arbitrary processes other than the process demonstrated below.

Production method B1:
Production method B1 is a method for producing a slurry-like mixture containing glass ceramic particles and a solvent, and a vitrification step for producing a glass body by melting and vitrifying a raw material composition, and a glass body A crystallization process for producing a glass ceramic, a pulverization process for producing the glass ceramic powder by pulverizing the glass ceramic, and a mixing process for dispersing the glass ceramic powder in a solvent. be able to.

Production method B2:
Production method B2 is another method for producing a slurry-like mixture containing glass ceramic particles and a solvent, and a vitrification step for producing a glass body by melting and vitrifying the raw material composition; A pulverization process for pulverizing a glass body to produce an uncrystallized glass powder, a crystallization process for heat-treating the uncrystallized glass powder to produce a glass ceramic powder, and a glass ceramic powder And a mixing step of dispersing in a solvent.

Production method B3:
Production method B3 is a method for producing a slurry-like mixture containing uncrystallized glass particles and a solvent, and a vitrification step for producing a glass body by melting and vitrifying the raw material composition; A pulverizing step of pulverizing the glass body to produce an uncrystallized glass powder particle and a mixing step of dispersing the non-crystallized glass powder in a solvent can be included.

Since the manufacturing methods B1 to B3 described above can be carried out in the same manner as the manufacturing methods A1 to A3 except for the mixing step, the details of each step will be omitted. The mixing step can be performed by dispersing glass ceramic particles or non-crystallized glass particles in the solvent. Moreover, the above-mentioned addition process and surface treatment process can also be included.

Manufacturing method B1-B3 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.

  Moreover, the slurry-like mixture of this invention makes it the same slurry-like mixture by using what cut the glass ceramic fiber and / or glass fiber (non-crystallized glass fiber) mentioned above short besides the glass granular material. be able to.

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

[Sintered glass ceramics]
The glass-ceramic sintered body according to the present invention is obtained by solidifying and sintering a powdery material containing glass powder, and contains at least a crystal containing a strontium titanate crystal. It is uniformly dispersed inside and on the surface of the ceramic sintered body. The manufacturing method of a glass ceramic sintered body has a vitrification process, a crushing process, a forming process, and a sintering process as main processes. Details of each step will be described below.

(Vitrification process)
In the vitrification process, a predetermined raw material composition is melted and vitrified to produce a glass body. Specifically, the raw material composition is put into a container made of platinum or refractory, and the raw material composition is melted by heating to a high temperature. By vigorously cooling the resulting molten glass, a vitrified glass body is formed. The conditions for melting and vitrification can be performed in accordance with the melting step and the cooling step in the above typical production method examples. Moreover, the shape of a glass body is not specifically limited, For example, plate shape, a granular form, etc. may be sufficient.

(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 of the shape and size of the molded body produced in the molding step. For example, when the pulverized glass is deposited on an arbitrary base material in the subsequent step and then sintered, the average particle diameter of the pulverized glass may be a unit of several tens of mm. On the other hand, when glass ceramics are molded into a desired shape or combined with other crystals, if the average particle size of the crushed glass is too large, it becomes difficult to mold, so the average particle size should be as small as possible. preferable. Therefore, the upper limit of the average particle size of the crushed glass is preferably 100 μm, more preferably 50 μm, and most preferably 10 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.

(Addition process)
By adding an arbitrary component to the crushed glass, an addition step of increasing the amount of the component can be included. This step is an optional step that can be performed after the pulverization step and before the molding step. This addition process can be implemented according to the addition process demonstrated with the manufacturing method of the said glass-ceramics granular material.

(Molding process)
The molding step is a step of molding the crushed glass into a molded body having a desired shape. In order to obtain a desired shape, it is preferable to use press molding in which crushed glass is put into a mold and pressed. It is also possible to form the crushed glass by depositing it on a refractory. In this case, the above slurry mixture can also be used.

(Sintering process)
In the sintering step, the crow compact is heated to produce a sintered body. As a result, the particles of the glass body constituting the molded body are bonded together, and at the same time, crystals containing strontium titanate crystals are generated, and glass ceramics are formed. For example, when a molded object is manufactured from the mixture which added the photocatalyst crystal to the ground glass, the crystal | crystallization which has more photocatalytic activity is produced | generated by glass ceramics. Therefore, higher photocatalytic activity can be obtained.

Although the specific procedure of the sintering process is not particularly limited, the step of preheating the molded body, the step of gradually raising the molded body to a set temperature, the step of holding the molded body at a set temperature for a certain time, the molded body May be gradually cooled to room temperature.

The sintering conditions can be appropriately set according to the composition of the glass body constituting the molded body. In the sintering process, in order to generate crystals from glass, it is necessary to match conditions such as the heat treatment temperature with the crystallization conditions of the glass constituting the compact. If the sintering temperature is too low, a sintered body having a desired crystal cannot be obtained. Therefore, sintering at a temperature higher than at least the glass transition temperature (Tg) of the glass body is required. Specifically, the lower limit of the sintering temperature is not less than the glass transition temperature (Tg) of the glass body, preferably not less than Tg + 50 ° C., more preferably not less than Tg + 100 ° C., and most preferably not less than Tg + 150 ° C. On the other hand, when the sintering temperature is too high, the precipitation of strontium titanate crystals and the like is reduced, the tendency for the photocatalytic activity to decrease is increased, and deformation called sagging occurs. Therefore, the upper limit of the sintering temperature is preferably Tg + 600 ° C. or less of the glass body, more preferably Tg + 550 ° C. or less, and most preferably Tg + 500 ° C. or less.

When the compact includes a photocatalytic crystal such as a crystalline strontium titanate crystal, it is necessary to set the sintering conditions in consideration of the amount, crystal size, crystal type, and the like of these crystals.

Further, the lower limit of the sintering time needs to be set according to the sintering temperature, but it is preferable to set it short for a high temperature and long for a low temperature. Specifically, the lower limit is preferably 3 minutes, more preferably 20 minutes, and most preferably 30 minutes in that the sintering can be sufficiently performed. On the other hand, if the sintering time exceeds 48 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 sintering time is preferably 48 hours, more preferably 24 hours, and most preferably 20 hours. In addition, the sintering time mentioned here refers to the length of time during which the firing temperature is maintained at a certain level (for example, the set temperature) or more in the sintering process.

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

In the glass ceramic sintered body formed by the sintering process, a crystal phase includes a crystal composed of one or more of strontium titanate crystals and solid solution crystals thereof. By containing these crystals, the glass-ceramic sintered body can have a high photocatalytic function.

  In addition to the glass particles, the glass ceramic sintered body of the present invention is the same by using a glass ceramic fiber and / or glass fiber (uncrystallized glass fiber) cut short as described above. Can be made.

[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, Of these, the glass ceramic layer is specifically a layer composed of an amorphous solid and a crystal. The glass ceramic layer contains one or more kinds of crystals selected from the group consisting of strontium titanate crystals and solid solution crystals thereof, and the crystal phase is uniformly dispersed inside and on the surface of the glass ceramics.

In the method for producing a glass-ceramic composite according to the present invention, a pulverized glass obtained from a raw material composition is fired on a substrate to form a glass-ceramic layer containing strontium titanate crystals and solid solution crystals thereof ( Firing step). In a preferred embodiment of the method of the present invention, a vitrification step in which the raw material composition is melted and vitrified to produce a glass body, a pulverization step in which the glass body is crushed to produce crushed glass, and the crushed glass on the substrate The baking process which forms a glass-ceramics layer by baking can be included.

In the present embodiment, “pulverized glass” is obtained by pulverizing a glass body obtained from a raw material composition, and is obtained by pulverizing amorphous glass and glass having a crystal phase. It is used to include a pulverized ceramic product and a crystal phase precipitated in a pulverized glass product. That is, “ground glass” may or may not have a crystalline phase. When the pulverized glass has a crystal phase, the glass body may be manufactured by heat treatment to precipitate the crystal phase and then pulverized, or after the glass body is crushed and heat treated, the crystal phase in the crushed glass You may manufacture by precipitating. In the case where the “pulverized glass” does not contain a crystal phase, the crystal phase can be precipitated by disposing the pulverized glass on a substrate and controlling the firing temperature (crystallization treatment).

Here, the crystallization treatment can be performed, for example, at each timing of (a) after the vitrification step and before the pulverization step, (b) after the pulverization step and before the firing step, and (c) at the same time as the firing step. Among these, from the viewpoints of easy sintering of the glass ceramic layer and no need for a binder, improvement of throughput due to simplification of the process, energy saving, and the like, the crystal in the firing is performed simultaneously with the firing step (c). It is preferable to perform the conversion treatment. However, when using a substrate having low heat resistance as the base material constituting the composite, (a) after the vitrification step and before the pulverization step, or (b) after the pulverization step and before the firing step, It is preferable to perform crystallization at the timing.

Hereinafter, details of each process will be described.

(Vitrification process)
In the vitrification process, a predetermined raw material composition is melted and vitrified to produce a glass body. Specifically, the raw material composition is put into a container made of platinum or refractory, and the raw material composition is melted by heating to a high temperature. By vigorously cooling the resulting molten glass, a vitrified glass body is formed. The conditions for melting and vitrification can be performed in accordance with the melting step and the cooling step in the above typical production method examples. Moreover, the shape of a glass body is not specifically limited, For example, plate shape, a granular form, etc. may be sufficient.

(Crushing process)
In the pulverization step, the glass body is pulverized to produce pulverized glass. By producing the pulverized glass, the glass body has a relatively small particle size, which makes it easy to apply on the substrate. Moreover, it becomes easy to mix other components by setting it as pulverized glass. The particle diameter and shape of the pulverized glass can be appropriately set according to the type of base material and the surface characteristics required for the composite. Specifically, if the average particle size of the pulverized glass is too large, it becomes difficult to form a glass ceramic layer having a desired shape on the substrate. Therefore, the average particle size is preferably as small as possible. Therefore, the upper limit of the average particle size of the crushed glass is preferably 100 μm, more preferably 50 μm, and most preferably 10 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.

(Addition process)
By adding an arbitrary component to the crushed glass, an addition step of increasing the amount of the component can be included. This step is an optional step that can be performed after the pulverization step and before the molding step. This addition process can be implemented according to the addition process demonstrated with the manufacturing method of the said glass-ceramics granular material.

(Baking process)
In the firing step, the composite is produced by placing the crushed glass on the substrate and then heating and firing. Thereby, the glass ceramic layer which has a crystal phase containing a photocatalyst crystal | crystallization is formed on a base material. Here, the specific procedure of the firing step is not particularly limited, but the step of placing the crushed glass on the base material, the step of gradually raising the temperature of the crushed glass placed on the base material to the set temperature, pulverization A step of holding the glass at a set temperature for a certain time and a step of gradually cooling the crushed glass to room temperature may be included.

<Arrangement on substrate>
First, crushed glass is placed on a substrate. Thereby, a photocatalytic characteristic 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 crushed glass on the substrate, it is preferable to arrange the slurry containing the crushed glass on the substrate with a predetermined thickness and size. Thereby, the glass ceramic layer which has a photocatalytic characteristic 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 pulverized glass on a base material, it is not restricted to the method of using the above-mentioned slurry, You may place the powder of pulverized glass directly on a base material. In addition, when the crushed glass to be placed on the base material already contains crystals by heat treatment, depending on the crystallinity, it is mixed with an organic or inorganic binder component, or a binder layer is interposed between the base material. You can also In this case, an inorganic binder is preferable in terms of durability against photocatalysis.

<Baking>
The firing conditions in the firing step can be appropriately set according to the composition of the glass body constituting the crushed glass, the type and amount of the mixed additive, and the like. Specifically, the atmosphere temperature at the time of firing can be controlled in the following two ways depending on the state of the crushed glass placed on the substrate.

The first firing method is a case where a desired photocatalytic crystal has already been generated in the crushed glass disposed on the substrate, for example, when a crystallization treatment is applied to a glass body or crushed glass. Is mentioned. In this case, the firing temperature can be appropriately selected within a temperature range of 1100 ° C. or less in consideration of the heat resistance of the substrate. However, when the firing temperature exceeds 1100 ° C., the generated photocatalytic crystal is easily transferred to another crystal. Become. Therefore, the upper limit of the firing temperature is preferably 1100 ° C., more preferably 1050 ° C., and most preferably 1000 ° C.

The second firing method is a case where the crushed glass disposed on the base material has not yet been crystallized and does not have photocatalytic crystals. In this case, it is necessary to perform crystallization treatment of glass simultaneously with firing. If the firing temperature is too low, a sintered body having a desired crystal phase cannot be obtained. Therefore, firing at a temperature higher than at least the glass transition temperature (Tg) of the glass body is required. Specifically, the lower limit of the firing 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 firing temperature becomes too high, the crystal phase containing the photocatalytic crystals tends to decrease and the photocatalytic properties tend to disappear, so the upper limit of the firing temperature is preferably Tg + 600 ° C. of the glass body, more preferably Tg + 550 ° C. Yes, most preferably Tg + 500 ° C.

Moreover, it is necessary to set baking time according to the composition of glass, baking temperature, etc. 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 48 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 firing time is preferably 48 hours, more preferably 24 hours, and most preferably 20 hours. In addition, the baking time said here refers to the length of the period when the baking temperature is hold | maintained more than fixed (for example, the said setting temperature) among baking processes.

  Further, in forming the glass ceramic layer of the glass ceramic composite of the present invention, in addition to the above glass powder particles, the above-mentioned glass ceramic fibers and / or glass fibers (non-crystallized glass fibers) are cut short. The same thing can be made by using.

[Glass]
The glass of the present invention produces a crystal phase containing crystals having photocatalytic activity from the glass by heating, and becomes the glass ceramic. That is, the glass of the present invention can be used as a precursor of glass ceramics. Such an uncrystallized glass contains the various forms listed above, for example, bead-like, fiber-like, plate-like, powder-like, composites with substrates, or glass. The form of a slurry-like mixture etc. can be taken.

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

Tables 1 to 3 show the glass compositions of the raw materials of Examples 1 to 16 and Comparative Examples 1 to 3 of the present invention, the heat treatment (crystallization) conditions, and the types of main crystal phases precipitated on these glasses.

Examples 1-13:
The glass ceramics of Examples 1 to 13 are high-purity materials that are used in ordinary glasses such as oxides, hydroxides, carbonates, nitrates, fluorides, and chloride compounds corresponding to the raw materials of the respective components. The raw materials were selected and used. These raw materials were weighed so as to have the composition ratios of the respective examples shown in Table 1 and uniformly mixed, and then charged into a platinum crucible, and 1200 ° C. in an electric furnace depending on the melting difficulty of the glass composition. It melt | dissolved for 1 to 24 hours in the temperature range of -1600 degreeC, and stir-homogenized and performed foam breakage etc. Thereafter, the temperature was lowered to 1500 ° C. or less, homogenized with stirring, and then rapidly cooled to produce a glass. About the obtained glass, it heated to the crystallization temperature described in each Example of Tables 1-3, and crystallized by hold | maintaining for the time described. Then, it cooled from the crystallization temperature and obtained the glass ceramic which has the target crystal phase as a main phase.

Examples 14 and 15:
The glass ceramics of Examples 14 and 15 are high-purity raw materials used for ordinary glasses such as corresponding oxides, hydroxides, carbonates, nitrates, fluorides, and chloride compounds as raw materials for the respective components. Selected and used. These raw materials were weighed so as to have the composition ratios of the examples shown in Table 2 and uniformly mixed, then charged into a platinum crucible, and 1200 ° C. or higher in an electric furnace depending on the melting difficulty of the glass composition. It melt | dissolved in the temperature range of 1600 degreeC for 1 to 24 hours, and homogenized with stirring, and foaming etc. were performed. Thereafter, the temperature was lowered to 1500 ° C. or less, homogenized with stirring, and then rapidly cooled to produce a glass. The obtained glass is pulverized in a ball mill, filled into a powder of 145 mesh (mesh size 106 μm) or less, filled in a mold, and pressure-molded with a uniaxial pressure press of 1 t / cm ² or more and molded. Got the body. Crystallization and sintering were performed by heating to the crystallization temperature described in the examples in Table 2 and holding for the time described. Then, it cooled from the crystallization temperature and obtained the glass ceramic sintered compact which has the target crystal phase.

Example 16:
For the glass ceramics of Example 16, high-purity raw materials used for ordinary glass such as corresponding oxides, hydroxides, carbonates, nitrates, fluorides, and chloride compounds are selected as raw materials for the respective components. Used. These raw materials were weighed so as to have the composition ratios of the examples shown in Table 2 and uniformly mixed, then charged into a platinum crucible, and 1200 ° C. or higher in an electric furnace depending on the melting difficulty of the glass composition. It melt | dissolved in the temperature range of 1600 degreeC for 1 to 24 hours, and homogenized with stirring, and foaming etc. were performed. Thereafter, the temperature was lowered to 1500 ° C. or less, homogenized with stirring, and then rapidly cooled to produce a glass. The obtained glass was pulverized by a ball mill, and a granular material having a size of 145 mesh (aperture 106 μm) or less was dispersed in a distilled water solvent to obtain a slurry mixture. This slurry was applied to a cordierite unglazed plate, dried at 80 ° C., heated to the crystallization temperature described in the table, and held for the stated time for crystallization and baking. Then, it cooled from crystallization temperature and obtained the glass-ceramic composite which has the target crystal phase and has surface gloss.

Comparative Example 1:
The sample of Comparative Example 1 is a high-purity raw material used for ordinary glass such as oxide, hydroxide, carbonate, nitrate, fluoride, chloride, metaphosphoric acid compound, etc. corresponding to each component. Selected and used. These raw materials are weighed so as to have the composition ratio shown in Table 3 and mixed uniformly, 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. It melt | dissolved in the temperature range for 1 to 24 hours, stirred and homogenized, and performed foam breakage. Thereafter, the temperature was lowered to 1500 ° C. or less, homogenized with stirring, and then rapidly cooled to produce a glass. Crystallization was not performed.

Comparative Examples 2-4:
The glass ceramics of Comparative Examples 2 to 4 have high purity used for ordinary glasses such as oxides, hydroxides, carbonates, nitrates, fluorides, chlorides, and metaphosphate compounds corresponding to the raw materials of each component. The raw materials were selected and used. These raw materials were weighed so as to have the composition ratio of the comparative example shown in Table 3 and uniformly mixed, then charged into a platinum crucible, and 1200 ° C. or higher in an electric furnace depending on the melting difficulty of the glass composition. It melt | dissolved in the temperature range of 1600 degreeC for 1 to 24 hours, and homogenized with stirring, and foaming etc. were performed. Thereafter, the temperature was lowered to 1500 ° C. or less, homogenized with stirring, and then rapidly cooled to produce a glass. About the obtained glass, it heated to the crystallization temperature described in the comparative example of Table 3, and it crystallized by hold | maintaining for the time described. Then, it cooled from the crystallization temperature and obtained glass ceramics.

Here, the types of precipitated crystal phases of the glass ceramics of Examples 1 to 16 and Comparative Examples 1 to 3 were identified by an X-ray diffractometer (manufactured by Philips, trade name: X'Pert-MPD).

As shown in Tables 1 to 3, the precipitated crystal phases of the glass ceramics of Examples 1 to 16 all contained SrTiO ₃ -based crystals having photocatalytic activity as the main crystal phase. On the other hand, Comparative Example 1 in which crystallization treatment is not performed and Comparative Example 2 in which the crystallization temperature is low are glasses, and in Comparative Example 3 that does not contain SrO, Belcovite (Ba ₃ (Nb _4.8 , Ti _1.2 ) Si ₄ O _25.4 ) crystallized on the surface, and Comparative Example 4 contained Paranite (Na ₂ TiSiO ₅ ) crystals.

The XRD result of Example 9 is shown in FIG. 1. Crystallization was carried out by changing the crystallization condition (temperature) from 650 to 900 ° C. with the same composition as in Example 9, and crystallized from X-ray diffraction (XRD) analysis. The calculation result of the degree of conversion (mass%) is shown in FIG. The peak near the incident angle 2θ = 32.4 ° is used, the calibration curve is prepared with unburned glass powder and strontium titanate reagent (99% made by high purity chemical), and the standard is LaB ₆ (made by NIST) It was.

Moreover, about each of the glass ceramics obtained in Examples 1-16 and Comparative Examples 1-3, the methylene blue decomposition activity index based on Japanese Industrial Standard JIS R1703-2: 2007 was evaluated. The evaluation results of the MB decomposition ability are shown in Tables 1-3.

More specifically, the decomposition activity index of methylene blue was determined by the following procedure. A 0.020 mM methylene blue aqueous solution (hereinafter referred to as an adsorption solution) and a 0.010 mM methylene blue aqueous solution (hereinafter referred to as a test solution) were prepared. Then, the surface of the sample and one opening of the quartz tube (inner diameter 10 mm, height 30 mm) are fixed with high vacuum silicone grease (manufactured by Dow Corning Toray) and adsorbed from the other opening of the quartz tube. The liquid was injected to fill the test cell with the adsorbent. Thereafter, the other opening of the quartz tube and the liquid surface of the adsorbing liquid are covered with a cover glass (manufactured by Matsunami Glass Industry Co., Ltd., trade name: white edge polished frost No. 1), and the light is not exposed to the glass. The adsorbed liquid was sufficiently adsorbed to the sample over 24 hours. About the adsorption liquid after adsorption | suction, the light absorbency with respect to the light of wavelength 664nm was measured using the spectrophotometer (The JASCO Corporation make, model number: V-650), and the light absorbency of this adsorption liquid was similarly measured about the test liquid. Adsorption was completed when the absorbance was greater.
At this time, from the values of absorbance (Abs (0)) and methylene blue concentration (c (0) = 10 [μmol / L]) measured for the test solution, the conversion coefficient K [μmol / L].
K = c (0) / Abs (0) (1)
Next, after removing the cover glass and replacing the liquid in the quartz tube with the test solution, the other opening of the quartz tube and the liquid surface of the adsorbing liquid were covered again with the cover glass, and ultraviolet rays of 1.0 mW / cm 2 were irradiated. And the light absorbency with respect to the light of wavelength 664nm after irradiating an ultraviolet-ray for 60 minutes, 120 minutes, and 180 minutes was measured.
From the value of absorbance Abs (t) measured t minutes after the start of ultraviolet light irradiation, the concentration C of the methylene blue test solution t minutes after the start of ultraviolet light irradiation using the following formula (2) (T) [μmol / L] was determined. Here, K is the conversion factor described above.
C (t) = K × Abs (t) (2)
A plot was created with C (t) determined as described above on the vertical axis and the irradiation time t [min] of ultraviolet rays on the horizontal axis. At this time, the slope a [μmol / L / min] of the straight line obtained from the plot was determined by the least square method, and the decomposition activity index R [nmol / L / min] was determined using the following equation (3).
R = | a | × 1000 (3)

As shown in Table 1 and Table 2, all of the glass ceramics of Examples 1 to 16 had an MB decomposition activity index of 3.0 nmol / l / min or more, and it was confirmed that they had MB decomposition activity.

As the above experimental results show, the glass ceramics of Examples 1 to 15 containing SrTiO ₃ crystals at a high concentration have excellent photocatalytic activity, and the photocatalytic crystals are uniformly dispersed in the glass. Therefore, it was confirmed that there is no loss of photocatalytic function due to peeling, and it can be used as a photocatalytic functional material excellent in durability.

On the other hand, the glass ceramics of Comparative Examples 1 and 2 each had an MB decomposition activity index of 0 nmol / l / min, confirming that they did not have MB decomposition activity. Although Comparative Example 3 crystallized on the surface, it was confirmed that the crystal was not a strontium titanate solid solution crystal but Ba ₃ (Nb _4.8 , Ti _1.2 ) Si ₄ O _25.4 . The MB decomposition activity index was evaluated to be 0 nmol / l / min. Further, since Comparative Example 4 was porous and permeated the MB aqueous solution, the MB decomposition activity index could not be measured.

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 (21)

Glass ceramics containing crystals of strontium titanate (SrTiO ₃ ) and / or a solid solution thereof and having photocatalytic activity. _2. The glass ceramic according to claim 1, comprising 5 to 50% of TiO ₂ component, ₂ to 50% of SrO component, and 10 to 85% of SiO ₂ component in mol% with respect to the total substance amount of oxide conversion composition. . Rn ₂ O component 0 to 40% and / or RO component 0 to 50% and / or Al ₂ O ₃ component 0 to 20% and / or mol% with respect to the total amount of substances of the oxide conversion composition ZrO ₂ component 0 to 10%, and / or Nb ₂ O ₅ component and / or Ta ₂ O ₅ component 0 to 25%, and / or As ₂ O ₃ component and / or Sb ₂ O ₃ component 0 to 5%
The glass ceramic of Claim 1 or 2 containing each component of these.
(In the formula, Rn is one or more selected from the group consisting of Li, Na, K, Rb, and Cs, and R is one or more selected from the group consisting of Mg, Ca, Ba, and Zn) The glass ceramic according to any one of claims 1 to 3, wherein the catalytic activity is expressed by light having a wavelength from an ultraviolet region to a visible region. The glass ceramic according to any one of claims 1 to 4, wherein a decomposition activity index of methylene blue based on Japanese Industrial Standard JIS R 1703-2: 2007 is 3.0 nmol / l / min or more. It is a manufacturing method of the glass ceramics in any one of Claim 1 to 5,
A melting step of mixing raw materials to obtain a melt;
A first cooling step for lowering the temperature of the melt to a crystallization temperature range;
A crystallization step of maintaining the temperature within the crystallization temperature region to produce crystals;
A second cooling step of obtaining a crystal-dispersed glass by lowering the temperature to outside the crystallization temperature region. It is a manufacturing method of the glass ceramics in any one of Claims 1-5, Comprising:
A melting step of mixing raw materials to obtain a melt;
A cooling step of cooling the melt to obtain glass;
A reheating step of raising the temperature of the glass to a crystallization temperature region;
A crystallization step of maintaining the temperature within the crystallization temperature region to produce crystals;
A re-cooling step of obtaining a crystal-dispersed glass by lowering the temperature outside the crystallization temperature region. The method for producing glass ceramics according to claim 6 or 7, wherein the crystallization temperature region is 580 ° C or higher and 1100 ° C or lower.   A photocatalyst comprising the glass ceramic according to claim 1.   The photocatalyst of Claim 9 which has a granular form or a fiber form. A slurry-like mixture containing the photocatalyst according to claim 10 and a solvent. The photocatalyst functional member containing the photocatalyst in any one of Claim 9 or 10. A sintered body obtained by sintering pulverized glass, wherein the sintered body includes the glass ceramic according to any one of claims 1 to 5. Raw material composition prepared such that the obtained glass body contains 5 to 50% of TiO ₂ component, ₂ to 50% of SrO component, and 10 to 85% of SiO ₂ component in mol% of the oxide equivalent composition A vitrification process for producing a glass body by melting the glass, a pulverization process for pulverizing the glass body to produce a crushed glass, and a molding process for forming the crushed glass into a molded body having a desired shape. The sintered body according to claim 13, wherein the sintered body is manufactured by a method comprising: a sintering step of heating the molded body to produce a sintered body. The sintered body according to claim 14, wherein the method further includes a step of mixing one or more kinds of crystals selected from TiO ₂ crystals, WO ₃ crystals, and ZnO crystals into the crushed glass. A glass comprising a base material and a photocatalytic functional layer provided on the base material, wherein the photocatalytic functional layer includes the glass ceramic according to any one of claims 1 to 5. Ceramic composite. Molten raw material composition prepared so that the obtained glass body contains 5% to 50% of TiO ₂ component, ₂ to 50% of SrO component, and 10 to 85% of SiO ₂ component based on mol% of oxide And vitrification to produce a glass body, a pulverization process for pulverizing the glass body to produce crushed glass, and firing after heating the crushed glass on a substrate The composite according to claim 16, which is produced by a method comprising the steps of: The composite according to claim 17, wherein the method further comprises a step of mixing one or more kinds of crystals selected from TiO ₂ crystals, WO ₃ crystals, and ZnO crystals into the crushed glass. The glass which produces | generates the crystal | crystallization which has photocatalytic activity from glass by heating, and becomes the glass ceramic in any one of Claim 1 to 5. 20. A glass according to claim 19 having a granular or fiber form. A slurry-like mixture containing the glass according to claim 20 and a solvent.