JP3136918B2 - Multifunctional material having antibacterial properties and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multifunctional material exhibiting antibacterial activity and a method for producing the same.

[0002]

2. Description of the Related Art It has been known that Ag and Cu have antibacterial properties. Such Ag is supported on a carrier such as apatite or zeolite, and the carrier is contained in a glaze and applied to a ceramic or the like. Japanese Patent Application Laid-Open No. Hei 5-201747 discloses a technique of firing at 1100 to 1300 ° C.

[0003]

When the powder carrying the antibacterial metal is kneaded with the glaze and calcined, the bacteria in the air do not come into contact with the antibacterial metal, and the antibacterial function is sufficiently improved. Can not be demonstrated. In addition, zeolite as a carrier is inferior in heat resistance and cannot be firmly fixed to ceramics or the like.

[0004]

In order to solve the above-mentioned problems, a multifunctional material according to the present invention comprises a glaze layer formed on a base material and a phosphoric acid-based material such as calcium phosphate, zirconium phosphate, and ammonium phosphate. When the specific gravity of the supported powder such as ceramics or zinc oxide is δt and the specific gravity of the glaze is δb,
A part of the supported powder satisfying 0 ≦ δt−δb ≦ 3.0 was embedded, and an antibacterial agent was fixed on at least the surface of the supported powder exposed from the glaze layer.

Here, the antibacterial agent includes metals containing Ag or Cu or oxides thereof. The finer the antibacterial agent, the larger the specific surface area and the higher the antibacterial property. In this method, finer antibacterial agents can be fixed to the carrier powder than fixed by heat treatment. The preferred antimicrobial agent has a particle size of several tens to 100 nm. An ion-exchangeable powder such as calcium phosphate can carry an antibacterial agent by ion exchange. If a fine antibacterial agent is directly fixed to the glaze without passing through the supporting powder, the antimicrobial agent does not exhibit sufficient antibacterial properties due to aggregation in the glaze, burying in the glaze, or solid solution in the glaze. .

The reason for satisfying 0 ≦ δt−δb ≦ 3.0 is that when the specific gravity of the supported powder is larger than the value specified in this range, the supported powder is locally localized during heat treatment. When buried completely in the glaze layer, bacteria easily accumulate on the surface of the multifunctional material in that part and the antibacterial property is deteriorated, and when the specific gravity of the supported powder is smaller than the value specified in the above range, This is because the carried powder is not firmly held in the glaze layer even if heat treatment is performed. Therefore, when using a supported powder on which an antibacterial agent described later is supported in advance, it is necessary to keep the specific gravity of the supported powder on which the antibacterial agent is supported within the above range.

The specific gravity of the glaze layer is changed continuously or stepwise so that the specific gravity increases as it approaches the surface of the base material. You may make it larger than the specific gravity of a body. This makes it possible to easily control the buried amount of the supported powder in the glaze layer.

[0008] Phosphate ceramics such as calcium phosphate, zirconium phosphate and ammonium phosphate or zinc oxide particles as a carrier powder are 0.1 to 3 µm.
Choose something of the order. Further, the supported powder may be a porous body, or may not be a porous body depending on the manufacturing method.

Further, calcium phosphate as a supporting powder,
Phosphate ceramics such as zirconium phosphate and ammonium phosphate or zinc oxide particles and Ag, Cu or their oxides form a white or transparent layer (depending on thickness), but titanium oxide is used as an antibacterial agent. In this case, the color becomes yellow, and when tin oxide is used, the color becomes red, which is not preferable. Further, it is considered that zinc oxide as a supported powder can exert more excellent effects because zinc itself has antibacterial activity and zinc oxide has a photocatalytic action.

On the other hand, a method for producing the above-mentioned multifunctional material is enumerated below. The glaze is applied on the unbaked base material, and then the base material is fired at a temperature higher than the softening temperature of the glaze. A part of the carrier powder is buried in the glaze layer by heat treatment at a temperature higher than 20 ° C. and lower than 320 ° C., and then the antibacterial agent is fixed to the surface of the carrier powder by photoreduction or heat treatment.

A glaze is applied on the unfired base material, and then the base material is fired at a temperature higher than the softening temperature of the glaze. After that, the antibacterial agent is applied to the surface of the glaze layer by photoreduction or heat treatment. Then, a part of the supported powder is embedded in the glaze layer by heat treatment at a temperature higher than the softening temperature of the glaze by 20 ° C. or more and less than 320 ° C.

A glaze is applied on the unfired base material, a supporting powder is applied on the glaze layer, and an antibacterial agent is fixed on the surface of the supporting powder by a photoreduction method or a heat treatment. The base material is fired at a temperature higher than the softening temperature by 20 ° C. or more and less than 320 ° C., and a part of the supported powder is buried in the glaze layer.

[0013] A glaze is applied on the unfired base material, and a support powder having an antibacterial agent fixed thereon is applied on the surface of the glaze layer by a photoreduction method or a heat treatment. The base material is baked at a temperature higher than or equal to ° C and lower than 320 ° C, and a part of the supported powder is embedded in the glaze layer.

A glaze is applied on the unfired base material, a supporting powder is applied on the glaze layer, and the base material is fired at a temperature higher than the softening temperature of the glaze by 20 ° C. or more and less than 320 ° C. At the same time, a part of the carrier powder is buried in the glaze layer, and thereafter, the antibacterial agent is fixed to the surface of the carrier powder exposed from the glaze layer by a photoreduction method or a heat treatment.

Here, the glaze layer is made of at least SiO ₂
A glaze containing a first component composed of an inorganic substance having a specific gravity of 2 to 4 and a second component having a large specific gravity may be formed such that the distribution of the specific gravity is inclined in the thickness direction by casting with sludge.

Also, instead of forming the glaze layer, Si
An amorphous layer corresponding to a glaze layer may be formed by applying an aqueous solution of a metal salt containing a group Ia or IIa element.

In the photoreduction method, a carrier (not necessarily porous) is added to an aqueous solution of silver nitrate, copper nitrate, zinc nitrate or the like, and the mixture is irradiated with light containing ultraviolet rays while stirring. The body is obtained by washing with distilled water and then drying. Examples of light containing ultraviolet light include an ultraviolet lamp, a BLB lamp, a xenon mercury lamp, and a fluorescent lamp. Further, the distance from the light source that emits light including ultraviolet rays to the aqueous solution is preferably 5 cm or more and 20 cm or less in order to obtain appropriate light intensity. Further, the irradiation time is preferably from 10 minutes to 60 minutes. This is because if the time is less than 10 minutes, the amount of the carried antibacterial agent is insufficient, and if the time exceeds 60 minutes, the amount of the carried antibacterial agent becomes unnecessarily large. In this case, when zinc oxide is used as the supported powder, the antibacterial agent is more firmly fixed by the photocatalyst.

On the other hand, in the method by heat treatment, the supported powder is added to an aqueous solution of silver nitrate, copper nitrate, zinc nitrate or the like and stirred, and this solution is heated at 80 to 120 ° C. for about 2 to 3 hours.
The resulting precipitate is collected, washed with distilled water, dried, and pulverized to a predetermined particle size.

[0019]

The loaded powder having the antibacterial agent fixed on its surface is partially exposed to the outside from the glaze layer or the amorphous layer, and the antibacterial agent comes into contact with the outside air, so that the antibacterial effect is sufficiently exhibited.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIGS. 1 to 3 are cross-sectional views of a multifunctional material having antibacterial properties according to the present invention. In each of the multifunctional materials according to the present invention, a glaze layer 2 is formed on the surface of a base material 1, The layer 2 holds an antibacterial layer 3 composed of a composite powder 4 in which an antibacterial agent 4b such as Ag or Cu is adsorbed on a carrier powder 4a having heat resistance higher than the softening temperature of the glaze.

In particular, in the multifunctional material shown in FIG. 1, the antibacterial agent 4b is fixed on the surface of the carrier powder 4a exposed from the glaze layer 2, and in the multifunctional material shown in FIG. The antibacterial agent 4b is also fixed on the surface of the carrier powder 4a buried in 2. This is due to the difference in the manufacturing method.

In the multifunctional material shown in FIG. 3, the distribution of the specific gravity of the glaze layer 2 changes continuously or stepwise so that the closer to the surface of the substrate 1, the larger the specific gravity of the glaze layer 2 becomes. Moreover, the specific gravity of the lower layer portion 2a close to the surface of the substrate 1 is
The specific gravity is set to be larger than the specific gravity of a. This makes it possible to easily control the amount of the buried powder 4a buried in the glaze layer 2, and to reliably expose a part of the supported powder 4a from the glaze layer 2.

As a method of forming the glaze layer 2 having such a structure, a glaze containing an inorganic substance mainly composed of SiO ₂ having a specific gravity of 2 to 4 and a second component having a large specific gravity is discharged. Casting is conceivable.

Although not shown, instead of forming the glaze layer 2, an amorphous layer corresponding to the glaze layer is formed by applying a metal salt aqueous solution containing Si and a group Ia or IIa element. Is also good. According to this configuration, the present invention can be applied to a building material or the like whose base material does not have a glaze layer.

Next, a method for producing a multifunctional material having antibacterial properties according to the present invention will be described with reference to FIGS. In the method shown in FIG. 4, first, a glaze 2 is applied on an unfired base material 1 as shown in FIG. 4A, and then the softening temperature of the glaze as shown in FIG. The base material is baked at a higher temperature, and thereafter, the supporting powder 4a is applied on the glaze layer 2 as shown in FIG. 3C, and then the glaze is softened as shown in FIG. A part of the carrier powder 4a is buried in the glaze layer 2 by a heat treatment at a temperature higher than the temperature by 20 ° C. or more and less than 320 ° C. Thereafter, as shown in FIG. Fix to the surface.

When the photoreduction method is used as a method for fixing the antibacterial agent 4b to the surface of the carrier powder 4a, the carrier powder 4a
Need not be made porous, and the degree of freedom of the process is increased. In addition, since the antibacterial agent 4b fills the gap between the supporting powders 4a, undulation and unevenness on the surface are reduced, so that dirt does not easily adhere.

The temperature of the heat treatment for embedding a part of the supporting powder 4a in the glaze layer 2 is set to be at least 20 ° C. higher than the softening temperature of the glaze.
When the temperature is lower than this range, if the temperature is lower than this range, the viscosity of the glaze layer 2 does not decrease, the burying amount of the supporting powder 4a is small, and the holding power is insufficient, and conversely, the temperature is lower than this range. This is because if the value of is increased, the viscosity of the glaze layer 2 becomes too low, and the carrier powder 4a is completely buried in the glaze layer 2.

In the method shown in FIG. 5, first, as shown in FIG. 5A, a glaze 2 is applied on an unfired base material 1, and then, as shown in FIG. The base material 1 is fired at a temperature higher than the softening temperature of the glaze, and thereafter, as shown in FIG. 3C, a composite powder composed of a carrier powder 4a having an antibacterial agent 4b fixed on the surface of the glaze layer 2 The body 4 is applied and then, as shown in FIG.
A part of the composite powder 4 is buried in the glaze layer 2 by heat treatment at a temperature higher than 20 ° C.

In the method shown in FIG. 5, when Ag is used as the antibacterial agent 4b, the Ag is oxidized to become Ag ₂ O. However, if fixed by the photoreduction method, only 10% by weight adheres at most. Since the method was discrete and no grain growth occurred, no activity was lost and no antimicrobial activity was reduced.

In the method shown in FIG. 6, first, as shown in FIG. 6A, a glaze 2 is applied on an unfired base material 1, and as shown in FIG. The carrier powder 4a is applied on the layer 2 and then the antibacterial agent 4b is fixed on the surface of the carrier powder 4a as shown in FIG. 4C, and then 20 ° C. or more and less than 320 ° C. below the softening temperature of the glaze. Firing the substrate at a high temperature. As a result, a part of the carrier powder 4a is embedded in the glaze layer 2 as shown in FIG. According to this method, the sintering can be completed only once, so that the productivity is improved.

In the method shown in FIG. 7, first, as shown in FIG. 7A, a glaze 2 is applied on an unfired base material 1, and then, as shown in FIG. On the glaze layer 2,
The composite powder 4 composed of the carrier powder 4a having the antibacterial agent 4b fixed on the surface is applied by a separate process (not shown), and then, as shown in FIG.
The base material is fired at a temperature higher than 20 ° C., and a part of the carrier powder 4 a is embedded in the glaze layer 2. According to this method, the sintering can be performed only once, as described above, so that the productivity is improved.

In the method shown in FIG. 8, first, glaze 2 is applied on unfired substrate 1 as shown in FIG. 8A, and then glaze 2 is applied as shown in FIG. The carrier powder 4a is applied on the layer 2, and then the base material is baked at a temperature higher than the softening temperature of the glaze by 20 ° C. or more and less than 320 ° C. as shown in FIG. Part is buried in the glaze layer 2 and thereafter, as shown in FIG.
The antibacterial agent 4b is fixed on the surface of the carrier powder 4a exposed from the surface. According to this method, the sintering can be performed only once, as described above, so that the productivity is improved.

Next, a specific example will be described. (Example 1) SiO _{2 is applied to} a cast body (unfired) of ceramics.
A glaze mainly composed of -Al ₂ O ₃ -Na ₂ O frit (softening temperature: 950 ° C., specific gravity: 2.8) is applied by a spray coating method, and 6 to 15 wt.
% Zinc oxide powder suspension (particle size: 0.1-1 μm, specific gravity: 5.7) is applied by spray coating, and then 1 wt% silver nitrate aqueous solution is applied 1-6 times by spray coating. A multifunctional material was obtained by irradiating light containing ultraviolet rays to fix the zinc ions while reducing the Ag ions, and firing at 1100 to 1200 ° C. A BLB lamp is used as a light source for irradiating light including ultraviolet rays, and a position where Ag on the surface is set to about 10 cm from the light source is set to 5 to 1
Irradiated for 0 minutes. In addition, Ag fixed to the cast molding
Has a particle size of several tens nm to 100 nm, and the molded body at that time turns brownish black by the application of Ag. This color changed to white with firing. Therefore, it is considered that Ag was changed to Ag ₂ O by firing. According to the observation of the fired body, the particle size of the produced Ag ₂ O is several tens nm to 10 nm.
0 nm and about 1 to 10% by weight based on the zinc oxide layer.

For evaluation of antibacterial activity, Escherichia coli (Escher
ichia coli strain W3110). That is, 0.15 ml (1 to 50,000 CFU) of a bacterial solution is dropped on the outermost surface of the multifunctional material previously sterilized with 70% ethanol, placed on a glass plate (10 × 10 cm), and brought into close contact with the outermost surface of the base material, and then left for 3 hours The sample was held. Thereafter, the bacterial solution of the sample was wiped with sterile gauze and collected in 10 ml of physiological saline, and the survival rate of the bacteria was determined and used as an index for evaluation. The viability of the bacterium in the sample was 10% or more and less than 30%.

Regarding the abrasion resistance test, a change in appearance was observed by performing a sliding abrasion test using a plastic eraser. In the abrasion resistance test for the above sample, 40
No change was observed for the reciprocating sliding of one time.

(Comparative Example 1) An SiO ₂ -Al ₂ O ₃ -Na ₂ O frit (softening temperature 9) was applied to a ceramic molded body (unfired).
A transparent glaze having a main component of 50 ° C. and a specific gravity of 2.8) is applied by a spray coating method, and 10 wt% of titania oxide sol (average particle size: 0.01 wt.
To 0.02 μm) by a spray coating method, and further apply a 1 wt% aqueous solution of silver nitrate 1 to 6 times by a spray coating method, and then irradiate with light including ultraviolet rays to obtain Ag.
Immobilized on titanium oxide while reducing ions, 1100-1
By firing at 200 ° C., a multifunctional material was obtained.

The obtained multifunctional material turned yellow. This tendency was the same when titanium oxide powder (P25, manufactured by Nippon Aerosol Co., Ltd.) was used. Further. When tin oxide sol (average particle size 0.003 to 0.008 μm) was used, the color changed to red.

Example 2 1-10 wt% aqueous silver nitrate solution calcium phosphate (average particle size 0.3-2 μm, specific gravity 3.
3) was immersed and irradiated with light including ultraviolet rays to fix Ag on calcium phosphate to obtain a supported powder. This is applied on a composite member obtained by applying a glaze mainly composed of SiO ₂ —Al ₂ O ₃ —Na ₂ O frit (softening temperature: 950 ° C., specific gravity: 2.8) to a ceramic molded body by spray coating. A multifunctional material was obtained by adding 5% to the glaze by a spray coating method and firing at 1100 to 1200 ° C. The viability of the bacteria for this sample is 1
It was less than 0%. In the abrasion resistance test, no change was observed after 40 reciprocal slidings.

(Comparative Example 2) On the surface of a ceramic tile base material,
A glaze layer (softening temperature: 680 ° C., specific gravity: 2.4) made of SiO ₂ —Al ₂ O ₃ —Na / K ₂ O frit is formed by a spray coating method, and 6 to 15 wt% zinc oxide powder is formed thereon. The suspension (particle diameter: 0.1 to 1 μm, specific gravity: 5.7) is applied by a spray coating method, and a 1 wt% aqueous silver nitrate solution is applied by a spray coating method 1 to 6 times.
The multifunctional material was obtained by irradiating light including ultraviolet rays to fix the zinc ions while reducing the Ag ions, and then performing a heat treatment at 900 ° C. In this sample, no change was observed in 40 reciprocal slidings in the wear resistance test, but the survival rate of the bacteria was 70% or more. Therefore, when the specific gravity difference between the supported powder and the glaze exceeds 3, the antibacterial properties are deteriorated.

Comparative Example 3 1-10 wt% aqueous silver nitrate solution calcium phosphate (average particle size 0.3-2 μm, specific gravity 3.
3) was immersed and irradiated with light including ultraviolet rays to fix Ag on calcium phosphate to obtain a supported powder. This was applied to a composite member obtained by applying a glaze layer (softening temperature: 535 ° C., specific gravity: 4.1) made of SiO ₂ —Al ₂ O ₃ —PbO frit to the surface of an alumina base material by a spray coating method. 5% by spray coating method, 8
By firing at 00 ° C., a multifunctional material was obtained. Although the survival rate of the bacterium in this sample was 10% or more and less than 30%, in the abrasion resistance test, scratches were formed in five or less reciprocal sliding operations. Therefore, it can be seen that when the difference in specific gravity between the supported powder and the glaze is smaller than 0, the wear resistance deteriorates.

Example 3 An SiO ₂ substrate was coated on the surface of an alumina substrate.
-Al ₂ O ₃ glaze layer consisting -PbO frit (softening temperature 5
35 ° C, specific gravity 4,1) is applied by the spray coating method, and a 6-15 wt% zinc oxide powder suspension (particle size 0.1-1 μm, specific gravity 5.7) is spray-coated thereon. And then apply 1 wt% silver nitrate aqueous solution
After applying by spray coating method six times, fixation to zinc oxide while irradiating light including ultraviolet rays to reduce Ag ions, and then heat treatment at each of 550 ° C, 700 ° C and 850 ° C. Multifunctional material was obtained.

When the heat treatment was carried out at 550 ° C., the survival rate (antibacterial property) of the bacterium was 10% or more and less than 30%, and the abrasion resistance was damaged by sliding 5 to 10 times. When the heat treatment is performed at 700 ° C., the survival rate (antibacterial property) of the bacteria is 10% or more and less than 30%, and the abrasion resistance is 10%.
Scratches were obtained after 40 slides. When the heat treatment was performed at 850 ° C., the survival rate (antibacterial property) of the bacteria was 70% or more, and the abrasion resistance was not damaged even after 40 times of sliding. Therefore, if the heat treatment temperature is lower than the softening temperature of the glaze by less than 20 ° C., the bonding between the zinc oxide as the supporting powder and the base material is not sufficient, so that the abrasion resistance is poor and the antibacterial property is higher than 320 ° C. It can be seen that is deteriorated.

[0043]

As described above, according to the present invention, the carrier powder having the antibacterial agent fixed on its surface is partially exposed to the outside from the glaze layer or the amorphous layer, and the antibacterial agent is exposed to the outside air. Because of the contact, the antibacterial effect can be sufficiently exhibited. In addition, since a part of the supported powder is buried in the glaze layer or the amorphous layer, the holding power is greatly improved, peeling or the like hardly occurs, and the antibacterial effect can be maintained for a long period of time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an antibacterial multifunctional material according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the multifunctional material.

FIG. 3 is a sectional view showing another embodiment of the multifunctional material.

FIG. 4 is a diagram illustrating a method for producing a multifunctional material having antibacterial properties according to the present invention.

FIG. 5 is a view for explaining another embodiment of the method for producing the multifunctional material.

FIG. 6 is a view for explaining another embodiment of the method for producing the multifunctional material.

FIG. 7 is a view for explaining another embodiment of the method for producing the multifunctional material.

FIG. 8 is a view for explaining another embodiment of the method for producing the multifunctional material.

[Explanation of Signs] 1 ... base material, 2 ... glaze layer, 3 ... antibacterial layer, 4 ... composite powder, 4
a: supported powder, 4b: antibacterial agent.

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C04B 33/34 C04B 33/34 (56) References JP-A-8-90699 (JP, A) JP-A-5-201747 (JP, A) JP-A-2-243159 (JP, A) JP-A-2-24738 (JP, A) JP-A-5-253544 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 C04B 33/34

Claims (10)

(57) [Claims] 1. A glaze layer is formed on a base material. When the specific gravity of the powder to be supported is δt and the specific gravity of the glaze is δb, the support satisfies 0 ≦ δt−δb ≦ 3.0. A multifunctional material having antibacterial properties, wherein a powder is provided so as to partially bury the powder, and an antibacterial agent is fixed on at least a surface of the carrier powder exposed from the glaze layer. 2. The multifunctional material having antibacterial properties according to claim 1, wherein the carrier powder contains at least one of phosphate ceramics such as calcium phosphate, zirconium phosphate and ammonium phosphate or zinc oxide. Multifunctional material with antibacterial properties characterized by the following. 3. The multifunctional material having antibacterial properties according to claim 1, wherein the specific gravity of the glaze layer changes continuously or stepwise so that the specific gravity increases as it approaches the substrate surface. A multifunctional material having antibacterial properties, wherein the specific gravity of the lower layer portion close to the substrate surface is higher than the specific gravity of the supported powder. 4. Applying the glaze on the unfired substrate, then firing the substrate at a temperature higher than the softening temperature of the glaze, thereafter applying the carrier powder on the glaze layer, A part of the supported powder is buried in the glaze layer by heat treatment at a temperature higher than the softening temperature of the glaze by 20 ° C. or more and less than 320 ° C. Then, the anti-bacterial agent is loaded by the photoreduction method, heat treatment or ion exchange method A method for producing a multifunctional material having antibacterial properties, characterized in that it is fixed to a surface. 5. Applying a glaze on an unfired substrate, then firing the substrate at a temperature higher than the softening temperature of the glaze, and then applying a photoreduction method, heat treatment or ion exchange on the glaze layer. A supported powder having an antibacterial agent fixed on the surface is applied by the method, and then a part of the supported powder is embedded in the glaze layer by a heat treatment at a temperature higher than the softening temperature of the glaze by 20 ° C. or more and less than 320 ° C. A method for producing a multifunctional material having antibacterial properties. 6. An unglazed base material is coated with a glaze, a supporting powder is coated on the glaze layer, and an antimicrobial agent is applied to the surface of the supporting powder by a photoreduction method, a heat treatment or an ion exchange method. Fix, then 20 ° C or more and 320 ° C above the softening temperature of the glaze
A method for producing a multifunctional material having antibacterial properties, wherein a base material is baked at a temperature lower than a high temperature and a part of a supported powder is buried in a glaze layer. 7. A glaze is applied on an unfired base material, and a support powder having an antibacterial agent fixed thereon by a photoreduction method, a heat treatment or an ion exchange method is applied on the glaze layer, and then the glaze is applied. A method for producing a multifunctional material having antibacterial properties, characterized in that the base material is baked at a temperature higher than the softening temperature of at least 20 ° C and less than 320 ° C and a part of the supported powder is buried in the glaze layer. . 8. Applying a glaze on the unfired base material, applying a supporting powder on the glaze layer, and then applying the base material at a temperature 20 ° C. or more and less than 320 ° C. higher than the softening temperature of the glaze. During firing, a part of the carrier powder is embedded in the glaze layer, and then the antibacterial agent is fixed to the surface of the carrier powder exposed from the glaze layer by photoreduction, heat treatment or ion exchange. A method for producing a multifunctional material having antibacterial properties. 9. The method for producing a multifunctional material having antibacterial properties according to claim 4, wherein the glaze layer is made of an inorganic material mainly composed of at least SiO ₂ and having a specific gravity of 2 to 4. A method for producing a multifunctional material having antibacterial properties, characterized in that a glaze containing a component and a second component having a large specific gravity is formed by sludge casting to form a distribution of specific gravity inclined in the thickness direction. 10. The method for producing a multifunctional material having antibacterial properties according to claim 4, wherein an aqueous solution of a metal salt containing Si and a Group Ia or IIa element is used instead of forming the glaze layer. A method for producing a multifunctional material having antibacterial properties, wherein an amorphous layer corresponding to a glaze layer is formed by coating.