JPH06198196A - Building material and production thereof - Google Patents

Abstract

PURPOSE:To provide a building material having high uniformity of material, excellent deodorizing, antimold and antimicrobial functions, high strength, and excellent durability which can be easily produced and easily worked into a desired form, and to provide an easy method of production thereof. CONSTITUTION:This material has such a structure that the surface and the area near the surface consists of a metal mixture essentially consisting of titanium oxide 10 and metal selected from platinum, palladium, etc., or a compsite body 14 of titanium and metal and that the inner area consists of a metal mixture of titanium 12 and metal selected from platinum, palladium, etc., or the composite body 14 of titanium and metal. The structure is continuous from the surface to the inner area. This building material is obtd. by producing a metal mixture, namely an alloy of titanium 12 and metal selected from platinum, palladium, etc., or the composite body 14 of titanium and metal, then working the alloy into a desired form, and subjecting the body to oxidation treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a building material and a method for producing the same, and more particularly to a metallic building material having a high photocatalytic function on the surface and having deodorant, antifungal and antibacterial effects and a method for producing the same. .

[0002]

2. Description of the Related Art It is known that semiconductors such as titanium oxide exhibit a photocatalytic function by light of a specific wavelength and have a deodorant, antifungal and antibacterial function by a strong oxidizing action. Antibacterial and antifungal magazine, Vol. 13, No. 5, p. 211 (1985), describes that a titanium oxide fine particle fixing membrane is useful as a sterilization reactor, and Japanese Examined Patent Publication No. 2-9850 discloses titanium oxide. A method for purifying waste using a semiconductor or the like in which a metal or a metal oxide is supported is described.

Conventionally, as a photocatalyst, titanium oxide, iron oxide, tungsten oxide, silicon oxide or the like having a semiconductor function or those carrying a metal such as platinum for the purpose of improving the catalytic function have been used. In order to utilize the fungicidal and antibacterial functions, it has been used by forming it into fine particles to form a fixed film on the surface or by dispersing the fine particles in the target substance to be treated.

[0004] In order to impart deodorant, antifungal and antibacterial functions to the building material by utilizing the photocatalytic function, spraying, dip coating, spin coating are applied as a method for applying the finely divided photocatalyst to the building material. The law is known. However, the film coated with the fine particle dispersion is
Microscopically, it lacks uniformity, resulting in poor efficiency of photocatalytic function, insufficient film strength, and insufficient adhesion strength to building materials, resulting in poor peeling resistance and for cleaning. There was a problem of being scratched or peeled off. In addition, thinning these semiconductor materials and adhering them to the material have also been proposed, but thinning technology is difficult, and there is concern that the acid treatment in the thinning process and the alkali treatment may adversely affect the building materials. However, it has not been put to practical use yet.

[0005]

DISCLOSURE OF THE INVENTION The object of the present invention is to provide a highly uniform material, excellent deodorant / mildew / antibacterial function, simple production, strength, and durability. It is to provide a building material which is excellent and can be easily processed into a shape according to the purpose. A second object of the present invention is to provide a simple and easy method for producing a building material which is uniform and has excellent durability, odor control, fungus control and antibacterial effect.

[0006]

[Means for Solving the Problems] Claim 1 according to the present application
The invention described is a building material, the surface and the vicinity thereof is composed of a metal oxide containing a metal oxide showing substantially photocatalytic activity and a second metal for improving the photocatalytic activity of the metal oxide, The inside is made of a metal mixture containing substantially the same metal as that constituting the metal oxide and a second metal for improving the photocatalytic activity of the metal oxide, and the surface and its vicinity and the inside are continuous. It is characterized in that

The invention according to claim 2 related to the present application is the building material according to claim 1, wherein the surface and its vicinity are substantially composed of a metal mixture represented by the general formula (I),

[0008]

Embedded image Formula (I) [AO _z ] _X [AM _y ] _1-X or [AO _z ] _X M _1-X (wherein A is a metal selected from the group consisting of Ti Ag Cu Zn). Where M is Pt, Au, Pd, Ag, C
represents a metal selected from the group consisting of u, Ni and Co,
z is the ratio of oxygen atoms bound to the metal A, and represents z ≦ 2, x is 0.3 ≦ x <1, y is an integer specific to the metal M bound to the metal A, and y = 1. Indicates either 2, 3, or 4. ) The inside is substantially composed of a metal mixture represented by the general formula (II),

[0009]

Embedded image General formula (II) [A] _X [AM _y ] _1-X or [A] _X M _1-X (wherein A represents a metal selected from the group consisting of Ti Ag Cu Zn, M is Pt, Au, Pd, Ag, C
represents a metal selected from the group consisting of u, Ni and Co,
x is 0.3 ≦ x <1, and y is an integer specific to the metal M that binds to the metal A, and represents y = 1, 2, or 3. ) It is characterized in that the surface, its vicinity and the inside are continuously formed.

A third aspect of the present invention relating to the present application is the method for producing a building material as described above, which comprises a metal which produces a metal oxide exhibiting photocatalytic activity and a second method for improving the photocatalytic activity of the metal oxide. The method is characterized in that a metal mixture containing a metal is produced, the metal mixture is processed into a desired shape, and then the processed metal mixture is subjected to an oxidation treatment.

The invention according to claim 4 relating to the present application is the method for producing a building material according to claim 3, wherein the general formula (I
Producing a metal mixture represented by I),

[0012]

Embedded image Formula (II) [A] _X [AM _y ] _1-X or [A] _X M _1-X (wherein A represents a metal selected from the group consisting of Ti Ag Cu Zn, M is Pt, Au, Pd, Ag, C
represents a metal selected from the group consisting of u, Ni and Co,
x is 0.3 ≦ x <1, and y is an integer specific to the metal M that binds to the metal A, and represents y = 1, 2, or 3. ) The metal mixture is processed into a desired shape, and then the metal mixture processed body is subjected to oxidation treatment.

[0013]

The building material of the present invention uses a mixture of a metal oxide having a photocatalytic function such as titanium oxide on the surface and in the vicinity thereof and a metal which improves the catalytic function of the metal oxide, and has titanium and the like described above inside. Since it is continuously formed by using a metal mixture of a simple metal that constitutes the metal oxide and the metal that improves the catalytic function, a uniform photocatalytic phase is formed on the surface, which is excellent for efficient photocatalytic reaction. Demonstrates deodorant, antifungal and antibacterial effects. Further, since the photocatalyst phase is rigidly and continuously formed, there is no separation of the catalyst phase,
Processing is also easy. Further, a metal mixture capable of forming a metal oxide such as titanium and a metal mixture (alloy) of the metal for improving the catalytic function are molded and processed, and then oxidized to have a photocatalytic function on the surface. Since the phase-formed building material is manufactured, a building material having excellent deodorant, mildew-proof and antibacterial effects and a uniform and arbitrary shape can be obtained by a simple method.

[0014]

The present invention will be described in more detail below.

The building material of the present invention comprises a metal mixture containing a metal oxide having substantially photocatalytic activity on the surface and in the vicinity thereof and a second metal for improving the photocatalytic activity of the metal oxide. Is a metal mixture containing substantially the same metal as that constituting the metal oxide and a second metal that improves the photocatalytic activity of the metal oxide, and the surface, its vicinity and the inside are continuous. In particular, the surface and its vicinity are substantially composed of a metal mixture represented by the following general formula (I) when represented by a preferable general formula,

[0016]

Embedded image General formula (I) [AO _z ] _X [AM _y ] _1-X or [AO _z ] _X M _1-X (wherein M is Pt, Au, Pd, Ag, Cu, Ni, C)
represents a metal selected from the group consisting of o, and x is 0.3 ≦
x <1, y is an integer unique to the metal M that binds to A,
Represents y = 1, 2, or 3. ) The inside is substantially composed of a metal mixture represented by the general formula (II),

[0017]

Embedded image General formula (II) [A] _X [AM _y ] _1-X or [A] _X M _1-X (wherein M is Pt, Au, Pd, Ag, Cu, Ni, C
represents a metal selected from the group consisting of o, and x is 0.3 ≦
x <1, y is an integer unique to the metal M that binds to A,
Represents y = 1, 2, or 3. ) The surface, its vicinity and the inside are continuously constructed. As for the respective proportions, the closer to the surface, the higher the content of the metal oxide [AO _z ] is, and in the interior, the metal simple substance [A] is contained.
Will increase in proportion.

Z represents the molar ratio of the oxygen atom [O] bonded to the metal A, and z ≦ 2. x represents a molar ratio showing the ratio of the metal oxide [AO _z ] or the metal [A] in the metal mixture and the metal [M] for improving the catalytic function, and the value of x is 0. 3 or more and less than 1 is required, and 0.
About 7 to 0.9 is preferable.

In the present invention, as a substance that can be used as a substance exhibiting a photocatalytic function, it is generally known as a semiconductor exhibiting a photocatalytic function.
Examples of the substance include titanium oxide, iron oxide, silver oxide, copper oxide, tungsten oxide, and the like.
Examples thereof include aluminum oxide, zinc oxide, silicon oxide, and strontium titanate. The metal oxide used in the building material of the present invention includes all of these semiconductors. Among these metal oxides, titanium oxide, iron oxide, silver oxide, copper oxide, zinc oxide and the like represented by the general formula (I) are preferable from the viewpoint of deodorant / mold / antibacterial effect. Strontium titanate is preferably used as the substance. Titanium oxide is particularly preferably used in terms of easiness of processing and cost.

The second metal for improving the photocatalytic activity of the metal oxide is a metal that can coexist with the metal oxide and serve as a reduction reaction site in the photocatalytic reaction, and is generally called a noble metal. Representative examples include elements of Group VIII group I and b. In the present invention, platinum, which is highly effective as the metal M for improving the catalytic function of the metal oxide [AO _z ] represented by the general formula (I),
Gold, palladium, silver, copper, nickel and cobalt are preferably exemplified. Of these, platinum, gold, palladium, and silver are preferable from the viewpoint of deodorant, antifungal, and antibacterial effects, and palladium is particularly preferable from the viewpoint of ease of processing and cost.

In the present invention, "substantially" is meant to include the presence of impurities and mixtures to the extent that the effects of the present invention are not impaired.

Here, the structure of the building material of the present invention is
The formula (I) and the general formula (II) are described below.
The metal oxide [AO_z] And M group
Metals selected from are similar structures to alloys by mixing.
Present. That is, (a) a metal oxide [AO_z〕only
A composite phase of a phase composed of a metal oxide and a metal M [A
M _y] And a finely and uniformly dispersed mixed structure (metal mixture
Body) {[AO_Z]_X[AM _y]_1-X} Or (b)
Metal oxide [AO_z] The phase consisting of only] and the metal M are fine
And uniformly dispersed metal mixture {[AO_Z]_XM_1-X}
Is to be presented. These are going to go inside
The metal oxide in the metal mixture [AO_z] To metal A
In addition, metal oxide [AO_z] And a metal M
It continuously changes to coalesce (alloy). At this time, metal
As A, deodorant, antifungal, antibacterial effect and processability, available
Titanium is preferably used because it is easy.

FIG. 1 is a model cross-sectional view showing the phase state of the metal mixture of the building material of the present invention when A is titanium Ti and M is palladium Pd. The surface and near and TiO ₂ phase 10 and TiPd ₂ phases 14 are dispersed, the TiO ₂ phase express a photocatalytic function, TiPd ₂ phase promotes the function. As it goes inside, the amount of Ti phase 12 not related to the photocatalytic function increases, and Ti phase 12 and Ti phase 12
A structure in which the Pd ₂ phase 14 is dispersed is formed, and these are continuously configured.

As described above, since the titanium oxide / metal phase having a photocatalytic function and the titanium / metal phase serving as a carrier constitute the same building material structure, the photocatalytic phase does not peel off from the carrier and is practically used. It is a building material with strength and resistance to peeling.

Next, a method for manufacturing a building material, which is the second invention of the present application, will be described. First, a metal mixture containing a metal that produces a metal oxide exhibiting photocatalytic activity and a second metal that improves the photocatalytic activity of the metal oxide is produced, processed into a desired shape, and then processed. A building material is manufactured by subjecting it to an oxidation treatment, which will be described by the following general formula (II).

Here, the metal that produces a metal oxide having photocatalytic activity is represented by A, and the second metal that improves the photocatalytic activity of the metal oxide is represented by M. First, a metal mixture or alloy represented by the following general formula (II) is produced,

[0027]

Embedded image General formula (II) [A] _X [AM _y ] _1-X or [A] _X M _1-X (In the formula, A represents a metal selected from the group consisting of Ti Ag Cu Zn, M is Pt, Au, Pd, Ag, C
represents a metal selected from the group consisting of u, Ni and Co,
x is 0.3 ≦ x <1, and y is an integer specific to the metal M that binds to the metal A, and represents y = 1, 2, or 3. ) After processing the alloy into a desired shape, the processed alloy body is subjected to oxidation treatment.

At room temperature, the alloy represented by the general formula (II) has a mixed structure in which the "alpha phase consisting of metal A and the composite phase of metal A and metal M" are finely and uniformly dispersed or "from metal A". Has a mixed structure in which the α phase and the metal M ”are finely and uniformly dispersed. x represents the molar ratio of the composite phase of metal A and metal M to metal M or the ratio of metal A to metal M, and y represents the molar ratio of metal M to metal A in the composite phase of metal A and metal M. Represents

A metal mixture (alloy) having such a mixed structure
After manufacturing and processing into a desired use shape such as plate and foil,
Oxidize. A pretreatment such as a heat treatment may be performed before the oxidation treatment. The molded alloy is subjected to surface cleaning and then subjected to an oxidation treatment. From the viewpoint of the uniformity of treatment and the strength of the photocatalytic phase, the oxidation treatment is preferably anodization treatment in an electrolyte solution. . When the oxidation treatment is performed, the surface of the “α phase made of metal A” in the mixed structure can be oxidized to form a metal oxide phase.

Thus, a phase composed of a metal oxide such as titanium oxide which plays a role of oxidative decomposition reaction in the photocatalytic reaction, and a phase composed of metal M which plays a role of promoting the photocatalytic reaction as a catalyst for the reduction reaction or a metal M and a metal. It is possible to easily obtain a rigid photocatalytic phase in which the composite phase with A is finely and uniformly dispersed on the alloy surface. In the general formula (II), the metal A is exemplified as a metal that forms a metal oxide particularly suitable for the present invention, but the present invention is not limited to this, and a metal that forms a metal oxide. For example, tungsten, iron,
Needless to say, aluminum or the like can be preferably used, and any other metal that can form a metal oxide exhibiting a photocatalytic function can be used.
Hereinafter, the present invention will be described in more detail with reference to specific examples.

Example 1 Production of Building Material Composed of Titanium-Palladium Binary System FIG. 2 shows a phase diagram of the metal mixture titanium-palladium binary system.

In the general formula (II), A is Ti, M is Pd, and z is 2. Metal mixtures (hereinafter referred to as alloys) A, B and C are x = 0.9, 0.8,
It was melted with a composition of 0.7.

The ingots of the alloys A, B and C were hot-rolled at 900 ° C. into a plate having a width of 110 mm and a thickness of 2 mm, and the weight was 5% by weight.
The surface oxide film was removed by pickling in a fluorine solution.
Next, as an interior metal tile, 100mm square, 1.6mm
Cut into thick pieces.

FIG. 3 is a schematic view of the anodizing apparatus. Each of the alloys is connected to the anode 16 and the cathode 18 is connected to metallic aluminum. The cell 20 is filled with a 1 wt% phosphoric acid aqueous solution 22. While observing the voltmeter 24 and the ammeter 26 and adjusting the voltage,
Electric power was supplied from the DC power supply device 28 to perform anodizing treatment. Thus, the metal tiles made of the above alloys are used as the anode 16 of the anodizing apparatus shown in FIG.
Mounted in a 1 wt% phosphoric acid aqueous solution, and voltage 10
By anodizing at 250 V, the titanium phase (α phase) in each alloy is oxidized, and a titanium oxide phase with a thickness of several tens of Å to several μm is formed on the surface to prevent odor, mildew and bacteria. A functional metal tile was obtained. On the surface of the obtained metal tile, in the general formula (I), A is Ti, M is Pd, and z.
Is 2 and x is 0.9, 0.8, 0.
A metal mixture such as 7 has been formed.

Example 2 Production of Building Material Composed of Titanium-Silver Binary System FIG. 4 shows a phase diagram of the metal mixture titanium-silver binary system.

In the general formula (II), A is Ti, M is Ag, and z is 2. Alloys D and E are x =
It was melted with a composition of 0.9 and x = 0.7.

The ingots of the alloys D and E were treated in the same manner as in Example 1 to obtain metal tiles having deodorant, antifungal and antibacterial functions. The surface of the obtained metal tile has the general formula (I)
In the case where A is Ti, M is Ag, and z is 2,
A metal mixture is formed in which x is 0.9 and 0.7, respectively.

(Test Example 1) Evaluation of Deodorizing Property / Peeling Resistance of Metal Tile FIG. 5 shows a schematic diagram of an apparatus for evaluating deodorizing property.

As a method of the deodorant evaluation test, a sample 32 of a metal tile is placed at the bottom of the quartz glass experimental tank 30. A standard gas generator 3 is placed in a quartz glass laboratory tank 30.
Aldehyde gas is supplied from 4 through the gas supply port 36. A pressure gauge 38 and a stirrer 40 are installed in the device,
With the gas sensor 42, the temperature / humidity meter 44, and the ultraviolet intensity meter 46, the internal state can be observed.
Deodorant property is evaluated by measuring the concentration of aldehyde gas according to 2.

The metal tile sample 32 obtained in each of Examples 1 and 2 was placed with the treated surface facing upward on the bottom of the quartz glass laboratory tank 30 of the deodorant evaluation test apparatus.

Aldehyde (5 ppm) was introduced from the gas supply port 36 into the evaluation device, and irradiation was performed for 60 minutes from the upper part of the evaluation device by a BL lamp (black lamp) (not shown). It was measured by gas chromatography, and the degree of reduction in the residual aldehyde ratio was used as an index of deodorant performance.

As a comparative product, a titanium oxide sol aqueous solution was applied by a spin coating method to form a titanium oxide-palladium thin film on a metal tile as a sample.
It evaluated similarly.

FIG. 6 is a graph showing changes in the residual concentration of aldehyde. In FIG. 6, a is a graph showing the aldehyde residual concentration of the metal tile obtained from alloy A,
Hereinafter, b is alloy B, c is alloy C, d is alloy D, and e is alloy E.
It is a graph which shows the aldehyde residual concentration of the metal tile obtained from. f is a graph showing the residual aldehyde concentration of the metal tile of the comparative product.

As shown in FIG. 6, the products of the present invention, that is, the metal tiles obtained by oxidizing the alloys A, B, C, D and E exhibited higher deodorizing performance than the comparative products.

FIG. 7 shows a schematic diagram of the peeling resistance evaluation test method. As shown in FIG. 7, the central portion of the surface of the metal tile sample was scratched with a cutter knife at a length of 10 mm at 2 mm intervals to form 5 × 5 squares.

Next, after the adhesive tape was attached to the squares and rubbed sufficiently from the top of the tape, the tape was peeled off, and the cut portion of the test piece was observed under a microscope, and the titanium oxide film remained without peeling off. The number of squares was counted and used as a parameter of peel strength.

As a comparative sample, a 5 cm square glass plate was prepared.
The same evaluation was performed by using a titanium oxide film having a thickness of 1 μm formed by the spin coating method.

Products of the present invention, namely alloys A, B, C, D,
The titanium oxide film was not peeled off in any of the metal tiles obtained by oxidizing E, and the result was 25. All the comparative samples peeled off and the result was 0. in this way,
These metal tiles obtained according to the present invention were excellent in peel resistance.

Among the metal oxides, titanium oxide gives various colors depending on its film thickness.
It is known that the titanium oxide film thickness is almost proportional to the anodic oxidation voltage. Therefore, when titanium oxide is used for the building material of the present invention, by controlling the oxidation voltage in the oxidation treatment, metal building materials of various colors can be obtained. Further, since the surface phase and the internal phase are continuously formed, regardless of the titanium oxide film thickness, excellent surface strength is exhibited, and thus a building material of a color developed according to the purpose is arbitrarily obtained by adjusting the oxidation potential. It is possible and is preferable in terms of design.

Since the building material of the present invention uses the above-mentioned specific alloy as a base material, it has excellent workability and can easily obtain an arbitrary shape. In addition, since anodizing allows fine and uniform surface oxidation treatment, even complex building materials have a uniform and excellent photocatalytic function, that is, excellent odor, mildew, and anti-deterioration properties. It may have a fungal function.

The building material of the present invention may be used as it is by processing a metal into an arbitrary shape as described above, or may be a deodorant / mildew / bacterial proof obtained by previously forming a thin film from an alloy and subjecting it to an oxidation treatment. A thin film material having a function can also be used by being bonded to various base materials.

As the method of using the building material of the present invention, as it is, it is used as a metal tile or an interior material, and a thin plate of the building material having the composite structure of the present invention is prepared, and the existing building material ceramics, It can also be used by being joined to mortar, glass, iron plate, aluminum plate and the like. In this way, according to the method of joining by using on the existing material,
It is possible to reduce the amount of alloy used, and it is possible to provide at low cost a building material with excellent deodorant / mold / antibacterial functions.

[0053]

EFFECT OF THE INVENTION The building material of the present invention is highly uniform in material, excellent in deodorant, antifungal and antibacterial functions, is easy to manufacture, has strength, and is excellent in durability. It is easy to process into a shape according to the purpose. According to the production method of the present invention, it is uniform and has excellent deodorant, antifungal and antibacterial effects,
A building material of any shape can be easily obtained.

[Brief description of drawings]

FIG. 1 is a model cross-sectional view showing a composite phase in a building material obtained from a titanium-palladium alloy.

FIG. 2 is a phase diagram of a binary metal-titanium mixture system.

FIG. 3 is a schematic view of an anodizing apparatus.

FIG. 4 is a phase diagram of a metal mixture titanium-silver binary system.

FIG. 5 is a schematic diagram of a deodorant evaluation test apparatus.

FIG. 6 is a graph showing changes in aldehyde residual concentration.

FIG. 7 is a schematic diagram of a peeling resistance evaluation test method.

[Explanation of symbols]

10 Titanium oxide (TiO ₂ ) phase 12 Titanium (Ti) phase 14 Titanium-palladium mixed (TiPd ₂ ) phase

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication location B01J 23/74 ZAB A 8017-4G E04C 2/08 Z 7904-2E (72) Inventor Toshio Saito Tokyo 2-5-14 Minamisuna, Koto-ku, Tokyo Incorporated Takenaka Corporation Technical Research Institute (72) Inventor Kan Hasegawa 2-5-14 Minamisuna, Koto-ku, Tokyo Incorporated Takenaka Corporation Technical Research Institute (72) Invention Akira Fujishima 5-10 710 Nakamaruko, Nakahara-ku, Kawasaki-shi, Kanagawa (72) Inventor, Kazuhito Hashimoto 2000, Kosugaya-cho, Sakae-ku, Yokohama, Yokohama

Claims (4)

[Claims] 1. A metal mixture containing a metal oxide having substantially photocatalytic activity on the surface and the vicinity thereof and a second metal for improving the photocatalytic activity of the metal oxide, and the interior thereof having substantially the same content. It is composed of a metal mixture containing the same kind of metal as the metal oxide and a second metal for improving the photocatalytic activity of the metal oxide, and the surface, its vicinity and the inside are continuously formed. Building material characterized by that. 2. The surface and the vicinity thereof are substantially composed of a metal mixture represented by the following general formula (I), and the general formula (I) [AO _Z ] _X [AM _y ] _1-X Or [AO _Z ] _X M _1-X (wherein A represents a metal selected from the group consisting of Ti Ag Cu Zn and M represents Pt, Au, Pd, Ag, C
represents a metal selected from the group consisting of u, Ni and Co,
z is the ratio of oxygen atoms bound to the metal A, and represents z ≦ 2, x is 0.3 ≦ x <1, y is an integer specific to the metal M bound to the metal A, and y = 1. Indicates either 2, 3, or 4. ) The inside is essentially composed of a metal mixture represented by the general formula (II), and the general formula (II) [A] _X [AM _y ] _1-X or [A] _X M _1-X (In the formula, A represents a metal selected from the group consisting of TiAgCuZn, and M represents Pt, Au, Pd, Ag, C.
represents a metal selected from the group consisting of u, Ni and Co,
x is 0.3 ≦ x <1, and y is an integer specific to the metal M that binds to the metal A, and represents y = 1, 2, or 3. The construction material according to claim 1, wherein the surface, the vicinity thereof, and the inside are continuously formed. 3. A metal mixture containing a metal capable of forming a metal oxide exhibiting photocatalytic activity and a second metal improving the photocatalytic activity of the metal oxide, and processing the metal mixture into a desired shape. After that, a method of manufacturing a building material, characterized by subjecting the processed metal mixture to an oxidation treatment. 4. A metal mixture represented by the general formula (II) is produced, and a compound of the general formula (II) [A] _X [AM _y ] _1-X or [A] _X M _1-X is prepared. (In the formula, A represents a metal selected from the group consisting of TiAgCuZn, and M represents Pt, Au, Pd, Ag, C.
represents a metal selected from the group consisting of u, Ni and Co,
x is 0.3 ≦ x <1, and y is an integer specific to the metal M that binds to the metal A, and represents y = 1, 2, or 3. 4. The method for producing a building material according to claim 3, wherein after the metal mixture is processed into a desired shape, the processed metal mixture is subjected to an oxidation treatment.