JP3322024B2 - Multifunctional material with antibacterial properties - 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.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. Hei 4-234303 discloses a prior art for imparting antibacterial properties to ceramic powders. Japanese Patent Application Publication No. 5-201747 is known. In these prior arts, an antibacterial metal such as Ag is supported on calcium phosphate, calcium hydrogen phosphate, calcium silicate, hydroxyapatite powder and the like.

[0003]

In order to impart an antibacterial function to ceramics using the above-mentioned powder having antibacterial properties, a powder carrying an antibacterial metal is kneaded with a glaze and fired, It is conceivable to fix a powder carrying an antibacterial metal on the layer.

However, 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 in the initial stage is sufficiently exhibited. Can not do it. Conversely, when the powder carrying the antibacterial metal is fixed on the glaze layer, the initial antibacterial function is fully exhibited, but if the antibacterial metal on the surface disappears due to elution or abrasion, rapid The antibacterial function is weakened.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a multifunctional material in which an intermediate layer mainly composed of glaze is formed on a base material, and an antibacterial layer is formed on the intermediate layer. The intermediate layer may contain, in addition to the glaze, a porous carrier powder having heat resistance higher than the softening temperature of the glaze and an inorganic antibacterial agent in an amount of 0.01% by weight to 10% by weight based on the carrier powder. The antibacterial layer contains the composite powder adsorbed at the following ratio, and the antibacterial layer is composed of the composite powder, or the inorganic antibacterial agent is applied on the intermediate layer in an amount of 0.05 μg / cm ^{2 to} 10 μg / cm ² . The antimicrobial agent was fixed at a ratio of metallic silver (hereinafter simply referred to as Ag).
In some cases) or silver oxide.

Here, the ratio of carrying (adsorbing) the antibacterial agent to the carrying powder is set to 0.01% by weight or more and 10% by weight or less. If the amount exceeds 10% by weight, Cu, Ag, Zn, etc., have a large specific gravity with respect to the supported powder, and may precipitate on the substrate side when the glaze is softened. On the other hand, in case of fixing directly antimicrobial agent on the intermediate layer, to a rate which is fixed to 0.05 [mu] g / cm ² or more 10 [mu] g / cm ² or less, the antimicrobial in the initial and less than 0.05 [mu] g / cm ² This is because the property cannot be ensured, and if it exceeds 10 μg / cm ² , it is difficult to suppress the elution amount of the antibacterial agent to a certain amount or less.

The antimicrobial agent may be Ag or an acid of Ag.
When Ag is present, the design is not impaired by making Ag exist in the form of an insoluble, colorless or white salt.

[0008] As the base material, one having heat resistance higher than the softening temperature of the glaze is selected, and examples thereof include ceramics, tiles, and base materials thereof.

[0009]

[Function] Since the composite powder carrying the antibacterial agent intervenes not only in the surface layer but also in the middle layer mainly composed of glaze, even if the antibacterial agent in the surface layer disappears due to abrasion or elution,
New antibacterial agents are exposed on the surface.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a cross-sectional view of an antibacterial multifunctional material according to the present invention, FIG. 2 is an enlarged cross-sectional view of an intermediate layer constituting the multifunctional material, and FIG. FIG. 4 is an enlarged sectional view showing another example of the multifunctional material having antibacterial properties according to the present invention, and FIG. 5 is a sectional view showing another example of the multifunctional material having antibacterial properties according to the present invention. is there.

In the multifunctional material according to the present invention, as shown in FIG. 1, an intermediate layer 2 is formed on the surface of a base material 1.
The antibacterial layer 3 is formed on the substrate.

The base material 1 includes, for example, ceramics, tiles, or a base material thereof. As shown in FIG. 2, the intermediate layer 2 mainly includes a glaze 4, and the glaze 4 has a heat resistance higher than the softening temperature of the glaze. The composite powder 5 is prepared by mixing a composite powder 5 in which an inorganic antibacterial agent 5b is adsorbed on a porous carrier powder 5a having the following formula.

The glaze 4 has a low softening point (400 ° C.).
) To a high softening point (about 1000 ° C.), and it is necessary to select a powder having a heat resistance higher than the softening temperature of the glaze 4 as the supporting powder 5a. 1200 ° C, specific gravity 3.
3), hydroxyapatite (heat resistant temperature 1200)
° C), zinc oxide (heat resistant temperature of 1200 ° C or more), zirconium phosphate (heat resistant temperature of 1000 ° C), zeolite (heat resistant temperature of 600 ° C), or the like. Further inorganic antibacterial agent 5b
Silver, copper, zinc, oxides thereof, or the like.

In the present invention, the composite powder 5 is prepared by supporting (fixing) the antibacterial agent 5b on the supported powder 5a.
As a supporting method, there are a method by heat treatment and a method by photoreduction.

The heat treatment is carried out by adding the above-mentioned porous carrier powder to an aqueous solution of silver nitrate, copper nitrate, zinc nitrate, etc., stirring and heating the solution at 80 to 120 ° C. for about 2 to 3 hours. The precipitate is collected, washed with distilled water and dried,
It is obtained by crushing to a predetermined particle size. Incidentally, the particle diameter is preferably 3 μm or less. If the particle size is larger than that, the sedimentation may occur on the base material side of the multifunctional material when the glaze is softened.

In the method using photoreduction, a porous carrier having a predetermined particle size 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. The preferable amount of the support is 0.01% by weight or more and 10% by weight or less with respect to the supported powder as described above.

The composite powder 5 obtained as described above is kneaded with the glaze 4 and applied on the substrate 1, and the solution of the composite powder 5 is further applied thereon. Then, after the heat treatment at a temperature lower than the heat resistance temperature of the base material 1 and higher than the softening temperature of the glaze,
Cool and solidify to obtain a multifunctional material.

FIG. 4 is a cross-sectional view showing another example of the multifunctional material having antibacterial properties according to the present invention. In the embodiment shown in FIG. 4, the antibacterial layer 3 is not made of composite powder. And an inorganic antibacterial agent 5b. In this case, the antibacterial layer 3
The ratio of immobilization of the antimicrobial agent 5b constituting the intermediate layer 2 to the intermediate layer 2 is 0.05 μg / cm ² or more and 10 μg / cm ² as described above.

Further, when using Ag as an antimicrobial agent. 5b, the antimicrobial layer 3 KI, KCl, may be brought into contact with aqueous halide solution, such as FeCl _3. In this way, Ag forms an insoluble and colorless or white salt as shown in FIG.
The design of the (glaze layer) is not hindered.

A specific embodiment will be described below. (Example 1) The base material is ceramic, and the glaze is SiO ₂ -Al ₂ O ₃ -Na.
₂ O frit (softening temperature: 950 ° C.), calcium phosphate was used for the supported powder, and silver was used for the antibacterial agent. In addition, calcium phosphate was added to the aqueous silver nitrate solution with stirring using a heat treatment method, and the solution was heat-treated at 80 ° C. for 2 hours to carry silver on calcium phosphate, and then pulverized to an average particle size of about 1 μm. At this time, the amount of silver adhering to the calcium phosphate powder was 3% by weight based on the calcium phosphate. Next, calcium phosphate powder carrying silver is kneaded with a glaze at 5 to 10% by weight based on the solid content of the glaze and coated on a substrate, and calcium phosphate powder carrying silver thereon is further applied to the solid content of the glaze. After applying 5 to 10% by weight, a heat treatment was performed at 1150 ° C., and the mixture was solidified by cooling to obtain a multifunctional material.

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 bacteria for the sample was less than 10%.

On the other hand, the amount of silver eluted was evaluated by immersing the sample in distilled water, stirring for 24 hours, and measuring the metal ions in the solution using an atomic absorption spectrophotometer to determine the amount of elution. The elution amount of silver in the above sample is 0.1 ppm
, And almost no silver elution was observed.

(Example 2) The base material was pottery, and the glaze was SiO _2-.
Al ₂ O ₃ —Na ₂ O frit (softening temperature: 950 ° C.), calcium phosphate was used for the supported powder, and silver was used as the antibacterial agent. In addition, calcium phosphate was added to the aqueous silver nitrate solution with stirring using a heat treatment method, and the solution was heat-treated at 80 ° C. for 2 hours to carry silver on calcium phosphate, and then pulverized to an average particle size of about 1 μm. At this time, the amount of silver adhering to the calcium phosphate powder was 3% by weight based on the calcium phosphate. Next, calcium phosphate powder carrying silver is kneaded with a glaze at 5 to 10% by weight with respect to the solid content of the glaze, coated on a base material, further coated with a 1% by weight aqueous silver nitrate solution and dried, and is then dried with a BLB lamp. After solidification by 30 spectral irradiations, 11
Heat treatment was performed at 50 ° C., and the mixture was solidified by cooling to obtain a multifunctional material.

The antibacterial evaluation (survival rate) of the above sample was less than 10%. Further, the elution amount of silver is 0.1
It was less than ppm, and almost no elution of silver was observed.

[0025]

As described above, according to the present invention, an intermediate layer mainly composed of glaze is formed on a base material, and an antibacterial layer is formed on the intermediate layer. The intermediate layer includes, in addition to the glaze, a composite powder in which an antibacterial agent is adsorbed on a porous carrier powder having heat resistance higher than the softening temperature of the glaze, and whether the antibacterial layer is composed of the composite powder. Fixing an inorganic antibacterial agent on the intermediate layer, as the antibacterial agent
Is composed of Ag or an oxide of Ag, so that the following effects are exhibited. The antibacterial agent fixed to the surface layer exhibits sufficient antibacterial properties at an early stage. Even if the antibacterial agent fixed to the surface layer disappears due to abrasion or elution due to washing, a new antibacterial agent is exposed on the surface, so that a stable antibacterial function can be continuously exhibited for a long period of time. In particular, since the antimicrobial agent embedded in the intermediate layer is fixed to the carrier, the antimicrobial agent does not aggregate in the intermediate layer and bacteria can be prevented from staying. The elution amount of the antibacterial agent can be suppressed by suppressing the amount of the antibacterial agent fixed on the surface layer portion or by fixing the antibacterial agent on a carrier having excellent adsorption power. By making Ag used as an antibacterial agent in the form of an insoluble, colorless or white salt, coloring by the antibacterial agent is prevented, and the design appearance formed by the glaze is not hindered.

[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 an enlarged sectional view of an intermediate layer constituting the multifunctional material.

FIG. 3 is an enlarged sectional view of a surface layer constituting the multifunctional material.

FIG. 4 is a cross-sectional view showing another example of the multifunctional material having antibacterial properties according to the present invention.

FIG. 5 is a cross-sectional view showing another example of the antibacterial multifunctional material according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base material, 2 ... Intermediate layer, 3 ... Antibacterial layer, 4 ... Glaze, 5 ... Composite powder, 5a ... Carrying powder, 5b ... Inorganic antibacterial agent.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-127975 (JP, A) JP-A-5-201747 (JP, A) JP-A-6-234585 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) A01N 59/16 A01N 25/08 B32B 7/00 C04B 33/34 C04B 41/86 C03C 8/00 C03C 4/00 JICST file (JOIS)

Claims (4)

(57) [Claims] 1. A multifunctional material in which an intermediate layer mainly composed of a glaze is formed on a base material, and an antibacterial layer is formed on the intermediate layer. A composite powder obtained by adsorbing an inorganic antibacterial agent at a rate of 0.01% by weight or more and 10% by weight or less with respect to the carrier powder on a porous carrier powder having heat resistance higher than the softening temperature of A multifunctional material having antibacterial properties, wherein the antibacterial layer is made of the composite powder, and the antibacterial agent is metallic silver or silver oxide. 2. A multifunctional material in which an intermediate layer mainly composed of a glaze is formed on a base material, and an antibacterial layer is formed on the intermediate layer. A composite powder obtained by adsorbing an inorganic antibacterial agent at a rate of 0.01% by weight or more and 10% by weight or less with respect to the carrier powder on a porous carrier powder having heat resistance higher than the softening temperature of The antibacterial layer contains an inorganic antibacterial agent in an amount of 0.05 μg / cm ² or more and 10 μg.
/ Cm ² or less, and the antibacterial agent is a metal
A multifunctional material having antibacterial properties, which is silver or silver oxide. 3. The multifunctional material having antibacterial properties according to claim 1, wherein the metallic silver is present in the form of an insoluble, colorless or white salt. Multifunctional material having. 4. The multifunctional material having antibacterial properties according to claim 1, wherein the base material is a ceramic, a tile, or a base material thereof.