JP2000044368A - Pottery having antimicrobial property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pottery having a sufficient antimicrobial property by forming a layer comprising a glazing agent containing a zinc component in a specific amount on the surface of a pottery substrate. SOLUTION: This pottery having a sufficient antimicrobial property is obtained by coating the surface of a pottery substrate 1 with a glazing agent containing a zinc component in an amount of 6-20 wt.% (converted into the amount of ZnO) by a coating method such as a spray coating method, a dip coating method, a roll coating method, a printing method or a spin coating method, and subsequently sintering the coated glazing agent to form the glazing agent layer 2 containing the zinc component in an amount of 6-20 wt.%. It is preferable that the surface of the pottery has a smoothness of <0.07 μm measured using a stylus type surface roughness measurement device. The sufficient antimicrobial property is obtained, for example, by making 1×105 to 5×105 cells of Escherichia coli adhere to the surface, covering the adhering surface with a polyethylene film in an atmosphere having a temperature of 37±1 deg.C and a relative humidity of >=90% and reducing the live cell of Escherichia coli to <1×103 after 24 hr.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to ceramics having sufficient antibacterial properties.

[0002]

2. Description of the Related Art It is well known that metal species such as silver, copper and zinc have an antibacterial effect. On the other hand, in the case of conventional ceramics, for example, in the case of sanitary ware, 3 to 5
Approximately by weight of zinc white (ZnO) is contained. Therefore, some antibacterial effects have been recognized in conventional sanitary ware.

[0003]

However, for example, in the case of antibacterial in sanitary ware, 1 × 10 ^{5 to} 5 × 10 ⁵ E. coli are adhered to the surface, and the temperature is 37 (± 1) degrees and the relative humidity is 9
If it is covered with a polyethylene film in an atmosphere of 0% or more and the number of viable bacteria does not become less than 1 × 10 ³ after 24 hours, it cannot be said that it has sufficient antibacterial properties. And, in the conventional sanitary ware, the antibacterial property satisfying the above conditions was not obtained. Then, in this invention, it aims at providing the ceramics which satisfy | fill the antibacterial property of the said conditions.

[0004]

According to the present invention, in order to solve the above-mentioned problems, a zinc component is added to the surface of a base material in an amount of 6 in terms of ZnO.
Disclosed is an antibacterial porcelain, which is characterized by forming a layer composed of glaze containing not less than% by weight. By setting the content of the zinc component in the glaze to 6% by weight or more in terms of the amount of ZnO, 1 × 10 ^{5 to} 5 × 10 ⁵ Escherichia coli was adhered to the surface, and the temperature was 37 (± 1) degrees and the relative humidity was 37 ° C. When coated with a polyethylene film in an atmosphere of 90% or more, the number of viable bacteria becomes less than 1 × 10 ³ after 24 hours, and sufficient antibacterial properties are exhibited even in sanitary ware.

In a preferred embodiment of the present invention, the content of the zinc component in the glaze is less than 20% by weight in terms of ZnO,
Preferably, the content is 17% by weight or less. When the content of the zinc component in the glaze is less than 20% by weight, preferably 17% by weight or less in terms of ZnO, poor appearance such as cloudiness or rough skin on the glaze layer surface is less likely to occur.

[0006]

FIG. 1 shows an embodiment of the ceramics of the present invention. In FIG. 1, a glaze layer 2 is formed on a ceramic body 1. The glaze layer 2 contains a zinc component in an amount of 6% by weight or more and less than 20% by weight, preferably 17% by weight or less in terms of ZnO. The valence of zinc in the zinc component is 2
It is part of the glass component in the glaze as a modifier component because of its valency.

Here, the reason why the zinc component is required to be 6% by weight or more in terms of the amount of ZnO is that zinc is uniformly present as a part of the glass component of the glaze, so that such an amount is required. That's why. However, because of such a structure, the amount of zinc hardly changes even during long-term use, and the antibacterial performance is maintained. Furthermore, when the amount of ZnO is increased, in a glaze containing an emulsifier such as zircon, the wettability between the glass component in the glaze and the emulsifier such as zircon is improved, and the exposure of emulsifier particles such as zircon is increased. Can be prevented from lowering the surface smoothness.

The reason why the zinc component is reduced to less than 20% by weight, preferably 17% by weight or less in terms of the amount of ZnO is based on the fact that the amount of zinc generated in the case of a transparent glaze exceeds the solid solution limit in glaze glass. Skin roughness due to the decrease in viscosity of the glaze glass component during firing due to cloudiness or excessively modified components generated in the case of glazes containing emulsifiers such as zircon (emulsifier particles tend to float on the surface due to buoyancy during firing This is to prevent appearance defects such as unevenness from occurring).

[0009] The ceramic of FIG.
It is obtained by applying a glaze raw material containing 6 to 20% by weight in terms of O amount to a surface of a ceramic molding base by a method such as spray coating, dip coating, roll coating, printing, and spin coating, and then firing.

Here, in the case of a glaze containing an emulsifier such as zircon, an aluminum component may be added to the glaze component so that Zn: Al = 1: 1. When the aluminum component is added, the solid solution of the zinc component in the glass is promoted during firing, the viscosity of the glaze glass component is reduced, the wettability with zircon is improved, and the unevenness based on the outermost layer of zircon is suppressed, and the skin becomes rough. Is less likely to occur.

Further, in the case of a glaze containing an emulsifier such as zircon, the amount of the alkali metal component and the alkaline earth metal component can be reduced by an increased amount of the zinc component with respect to the conventional glaze composition. Good. By doing so, the viscosity of the glaze glass component at the time of firing is suppressed from lowering, so that rough skin due to the decrease in the viscosity of the glass component is less likely to occur.

Here, a 50% particle size (D
50) When a glaze material of 1.5 μm or less or vitrified frit glaze is used, the surface roughness Ra becomes less than 0.07 μm by a stylus type surface roughness measuring device (JIS-B0651), and the surface becomes smooth. The antifouling property based on the above can be simultaneously exhibited. Furthermore, if the surface is smooth, it is difficult for water to stay in that portion, and it is therefore difficult for bacteria to propagate.

Further, by adding a lithium compound to the glaze layer, surface smoothness and glossiness are improved. For example, when petalite (feldspar) or lithium carbonate is selected as the lithium compound, the melting temperature of the glaze decreases during firing and the viscosity decreases, so that pinholes are reduced, surface smoothness is improved, and gloss is reduced. The effect of ascent will be obtained.

The porcelain to which the present invention can be applied can be used, for example, for sanitary ware such as urinals, toilets, sana of toilets, toilet tanks, basins of wash basins, tiles, dishes, ceramic plates and the like. In particular, when used for toilets and toilet sana, it is convenient to use zinc as an antibacterial metal from the following viewpoints. That is, as shown in FIG. 2, zinc oxide is a compound whose elution is promoted on the alkali side. On the other hand, the adhesion of urine (mainly composed of calcium phosphate) to the toilet or the sana surface of the toilet proceeds in an alkaline solution containing ammonia. Bacterial propagation in toilet bowls and toilet sana is thought to be due to the formation of surface irregularities due to the adhesion of uroliths, where water and organic matter serving as bacterial nutrients can always remain. Should occur in the environment.

[0015] From the above, it is sufficient that the antibacterial agent is flushed in an alkaline environment in a toilet bowl or a sana of a toilet bowl, and if zinc is used as a component fixed in the glaze, elution occurs in an alkaline environment. Therefore, the antimicrobial component can be intensively eluted only when necessary.

[0016]

Example (Example 1)

[0017]

[Table 1]

5% by weight of ZnO powder was added to the glaze raw material having the composition shown in Table 1, and the amount of ZnO in all the glaze raw materials was adjusted to 10% by weight. 600g of this glaze base material and water 4
00 g and 1 kg of alumina balls were placed in a ceramic pot having a volume of 2 liters and ground by a ball mill for about 65 hours. When the particle size of the glaze slurry obtained after pulverization was measured using a laser diffraction particle size distribution meter,
m is 98% or less, and 50% average particle diameter (D50) is 1.2 μm.
m. Next, using a sanitary ware body slurry prepared using silica sand, feldspar, viscosity and the like as raw materials, 70 × 150 mm
Was prepared, the glaze slurry obtained as described above was applied to the plate-shaped test piece by a spray coating method, and baked at 1100 to 1200 ° C to obtain a sample.

For evaluation of antibacterial activity, E. coli (Esc
hericia coli, IFO 3972). That is, 0.2 ml of the bacterial solution (the number of bacteria: 1 × 10 ^{5 to} 5 × 10 ⁵ ) is applied to the surface of the glaze layer previously sterilized with 70 vol% ethanol and dried.
Was dropped, covered with a 45 × 45 mm polyethylene film and adhered closely, and allowed to stand in an atmosphere at a temperature of 37 ± 1 ° C. and a relative humidity of 90% or more for 24 hours. Thereafter, the film was peeled off, stamped with an NA medium, and cultured in an environment at a temperature of 35 ± 1 ° C. for 16 to 20 hours to measure the number of viable cells. At the same time, the antibacterial activity was determined by comparing the number of bacteria tested and cultured on a blank sample having no antibacterial activity with the number of bacteria tested and cultured on the sample. The criteria are shown below. K = [the number of cells in the test medium] / [the number of cells in the blank medium] ×: K ≧ 1/10 Δ: 1/10 ² ≦ K <1/10 ○: 1/10 ⁵ ≦ K <1 / 10 ² ◎: K = 0 As a result, the antibacterial property of the sample was ◎.

Further, the appearance was evaluated by measuring the surface roughness and glossiness. As for the surface roughness of the sample surface, the center line average roughness Ra was measured using a stylus type surface roughness measuring device (JIS-B0651). As a result, Ra = 0.0
It was 3 μm. The gloss is measured by the specular gloss measurement method (J
According to IS-Z8741), a 60-degree specular gloss Gs (6
0 °) was measured. As a result, Gs (60 °) = 94.
It was one.

Example 2 10% by weight of ZnO powder was added to a glaze raw material having the composition shown in Table 1, and Zn in all glaze raw materials was added.
The O content was adjusted to be 14% by weight. 600 g of this glaze base material, 400 g of water and 1 kg of alumina balls were placed in a 2 liter pottery pot and ground by a ball mill for about 66 hours. The particle size of the glaze slurry obtained after pulverization was measured using a laser diffraction type particle size distribution meter.
0) was 1.2 μm. Next, using a sanitary ware body slurry prepared using silica sand, feldspar, viscosity, etc. as raw materials,
A plate-like test piece of 0 × 150 mm was prepared, the glaze slurry obtained as described above was applied to the plate-like test piece by a spray coating method, and baked at 1100 to 1200 ° C. to obtain a sample. When the obtained sample was evaluated in the same manner as in Example 1, the antibacterial property was ◎ and the appearance was Ra =
0.04 μm, Gs (60 °) = 93.5.

(Comparative Example 1) 2 kg of a glaze base material having the composition shown in Table 1 (ZnO content is 5% by weight), 1 kg of water and 4 kg of cobblestone were placed in a pot of 6 liters in pottery.
It was ground for about 18 hours by a ball mill. When the particle size of the glaze slurry obtained after pulverization was measured using a laser diffraction type particle size distribution analyzer, 65% and 50% were found to be 10 μm or less.
The average particle size (D50) was 6.2 μm. Next, using a sanitary ware body slurry prepared using silica sand, feldspar, viscosity, etc. as raw materials, a plate test piece of 70 × 150 mm was prepared,
The glaze obtained as described above was applied to a plate-shaped test piece by a spray coating method, and fired at 1100 to 1200 ° C to obtain a sample. About the obtained sample,
When evaluated in the same manner as in Example 1 and Example 2, the antibacterial property was Δ, the appearance was Ra = 0.10 μm, and the Gs (60 °) = 9.
5.0.

Comparative Example 2 17% by weight of ZnO powder was added to a glaze raw material having the composition shown in Table 1, and Zn in all glaze raw materials was added.
The amount of O was adjusted to be 20% by weight. 2 kg of this glaze base material, 1 kg of water and 4 kg of cobblestone were placed in a 6-liter pottery pot and ground by a ball mill for about 18 hours. When the particle size of the glaze slurry obtained after pulverization was measured using a laser diffraction particle size distribution meter,
m: 67%, 50% average particle size (D50): 5.7 μm
m. Next, using a sanitary ware body slurry prepared using silica sand, feldspar, viscosity and the like as raw materials, 70 × 150 mm
And the glaze obtained as described above was applied to the plate-like test piece by a spray coating method.
A sample was obtained by firing at 100 to 1200 ° C.
When the obtained sample was evaluated in the same manner as in Example 1 and Comparative Example 1, the antibacterial property was ◎ and the appearance was Ra = 0.52 μm.
m, Gs (60 °) = 29.6.

[0024]

[Table 2]

Table 2 summarizes the evaluation results. From Table 2, it can be seen that high antibacterial properties can be obtained when the amount of ZnO in the glaze of ordinary ceramics is greater than 5% by weight. However, when the amount of ZnO is too large, it can be seen that a satisfactory appearance as a ceramic cannot be obtained.

[0026]

According to the present invention, a ceramic having sufficient antibacterial properties can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a ceramics according to the present invention.

FIG. 2 is a graph showing the amount of zinc eluted in an acid or alkali solution.

[Explanation of symbols]

 1. Ceramic body 2. Glaze layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaaki Ito 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Touchi Kiki Co., Ltd. (72) Atsushi Kitamura 2 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka 1-1-1, Totoki Kiki Co., Ltd. (72) Inventor Masami Ando 2-1-1, Nakajima, Kokurakita-ku, Kitakyushu-city, Fukuoka Prefecture Tochiki Koki Co., Ltd. (72) Koichi Hayashi Kokura, Kitakyushu-shi, Fukuoka 2-11-1, Nakajima, Kita-ku, Tokyo Toki Kiki Co., Ltd. (72) Inventor: Satoshi Horiuchi 2-1-1, Nakajima, Kokurakita-ku, Kitakyushu, Fukuoka Prefecture Totoki Kiki Co., Ltd. (72) Katsuhiro Kawakami, Fukuoka Inventor No. 1-1, Nakajima, Kokurakita-ku, Kitakyushu-city

Claims (7)

[Claims] 1. An antibacterial porcelain, characterized in that a glaze layer containing a zinc component in an amount of at least 6% by weight in terms of ZnO is formed on the surface of a substrate. 2. The antibacterial porcelain according to claim 1, wherein a layer made of a glaze containing less than 20% by weight of a zinc component in terms of ZnO is formed on the surface of the base material. 3. The ceramic material having antibacterial properties according to claim 1, wherein a layer made of a glaze containing 17% by weight or less of a zinc component in terms of ZnO is formed on the surface of the base material. 4. A surface roughness measuring device (JIS-B0651) for measuring the surface roughness Ra of the ceramics by using a stylus type surface roughness measuring apparatus (JIS-B0651).
The ceramic having antibacterial properties according to any one of claims 1 to 3, wherein the ceramic is less than 07 µm. 5. The porcelain having antibacterial properties according to claim 1, wherein an emulsifier is added to the glaze. 6. The pottery having antibacterial properties according to claim 1, wherein the pottery is a toilet or a sana of a toilet. 7. The porcelain having antibacterial properties according to claim 1, wherein the porcelain is a basin of a wash basin.