JP2002060285A - Method of producing antibacterial pottery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce pottery having excellent antibacterial properties at a low cost. SOLUTION: The antibacterial pottery is produced by sticking a liquid body containing an antibacterial metal and/or an antibacterial metal compound on the surface of a pottery body or the surface of a glaze layer formed on the surface of the pottery body and firing the coated pottery body. Thereafter, the obtained antibacterial pottery is irradiated with an energy beam such as a carbon dioxide layer beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing antibacterial porcelain, and more particularly to a method for producing porcelain having excellent antibacterial properties.

[0002]

2. Description of the Related Art In recent years, as the standard of living has been improved, the concept of hygiene of the general public has been remarkably improved, and research on antibacterial technology for cutting off the growth of bacteria as well as disinfecting technology has been actively conducted. . Antibacterial products utilizing antibacterial properties such as silver, copper, and zinc have been developed in various fields including daily necessities.

[0003] For tiles and other ceramic products,
Research on the technology of imparting antibacterial properties has been made.Conventionally, a method of producing antibacterial tiles by mixing silver powder, copper powder, zinc powder, etc. together with the raw material clay of the tile, pressing and firing, and firing the mixture. It has been proposed (Japanese Utility Model Laid-Open No. 3-50032).

However, in the antibacterial tile described in Japanese Utility Model Laid-Open No. 3-50032, the tile base itself is antibacterial, but when a glaze layer is formed on the surface thereof, the antibacterial property of the tile base is improved by the glaze layer. It will be hidden. For this reason, there is a drawback that a tile construction surface excellent in antibacterial property cannot be obtained unless the construction mode is as an unglazed tile.

Japanese Patent Application Laid-Open No. 7-196384 discloses a glaze obtained by mixing a glaze raw material with metallic silver, silver oxide, or a silver compound insoluble, hardly soluble or easily soluble in water to provide antibacterial properties. A method for producing an antibacterial porcelain which is applied directly to the surface or coated with a usual glaze on the surface of a molding base and further applied on another glaze layer and fired is described.

JP-A-8-73256 discloses a method in which a liquid containing silver and / or a silver compound is applied to the surface of a ceramic body or a glaze layer formed on the surface of the ceramic body. A method for producing antibacterial ceramics by firing,
The liquid containing the silver and / or silver compound is attached to the surface of the base or the surface of the glaze layer by printing, and the amount of silver attached to the surface of the base or the surface of the glaze layer is 0.1 to 200 mg / cm ² . A manufacturing method is described.

[0007]

An object of the present invention is to further enhance the antibacterial activity of such an antibacterial glaze layer.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for producing an antibacterial ceramic, comprising the steps of: providing an antibacterial metal and / or an antibacterial metal on a surface of a ceramic substrate or a glaze layer formed on the surface of the ceramic substrate; A method for producing an antibacterial ceramic by adhering a liquid containing a compound and then firing the same, wherein the surface of the ceramic is irradiated with energy rays after firing.

The present inventors have repeatedly studied the antibacterial activity of a glaze layer containing an antibacterial metal and / or a compound of an antibacterial metal. It has been found that it is significantly improved. The present invention is based on this finding.

In the present invention, silver is preferred as the antibacterial metal. Further, a laser beam is preferable as the energy ray.

In the present invention, after the irradiation of the energy ray, the surface of the ceramic is further treated with a water-repellent agent to form a water-repellent layer while exposing the antibacterial metal. An effect can also be obtained.

The ceramics to which the present invention is applied are tiles, Japanese-style and Western-style toilets, urinals, washbasins, handwashers,
This includes sanitary equipment such as foot washers, handrails, faucet handles, door handles, decorative items such as Japanese and Western dishes and vases, and also enamels.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

In the present invention, examples of the liquid containing the antibacterial metal and / or the compound of the antibacterial metal include the following. Glaze mixed with antibacterial metal and / or compound of antibacterial metal. An antibacterial metal and / or a paint mixed with an antibacterial metal compound. A suspension in which an antibacterial metal and / or a compound of the antibacterial metal is suspended in water, hydrophilic mineral oil, aqueous polymer solution, organic solvent such as alcohol, and the like.

In the present invention, silver, silver,
Copper, zinc, titanium, platinum, gold, and the like.Examples of the compound of the antibacterial metal include oxides, nitrates, and the like of these antibacterial metals.
Phosphate, sulfide, chloride, sulfate, peroxide, bromide, iodide and the like can be used. When an antimicrobial metal such as metallic silver is used, its particle size is 0.5 to 20 μm.
It is preferred that

In the present invention, a liquid material containing such an antibacterial metal and / or a compound of the antibacterial metal is subjected to curtain hanging, spraying, brushing, mist hanging, printing, or the like to form a ceramic body surface (this body is , May be fired or unfired) or adhere to the surface of the glaze layer formed on the surface of the ceramic body.

The amount of the antibacterial metal and / or the compound of the antibacterial metal is 0.1 to 100 mg / cm ^2, especially 0.1 to 5 mg / cm ² , based on the surface area of the fired ceramic.
0 mg / cm ² is preferable.
In the case where the glaze layer is formed on the surface, the antibacterial metal equivalent concentration in the glaze layer after firing is 0.1 to 10% by weight, particularly 0.1 to 10% by weight.
It is preferable that the content be 5.0% by weight.

In the case of the glaze described above, for example, an antibacterial metal and / or a compound of an antibacterial metal is added to a glaze having the following usual glaze composition (lime-zinc glaze) by 0.2. It is preferred to mix in the range of up to 6.0% by weight. [Glaze composition (% by weight)] Feldspar: 30-60 Lime: 5-15 Clay: 1-10 Silica sand: 5-20 Zinc: 5-20 Pigment: 0-5

Further, in the case of the above-mentioned paint, for example, an antibacterial metal and / or
Alternatively, it is preferable to mix the antimicrobial metal compound in the range of 0.1 to 10.0% by weight on an external basis. [Paint composition (% by weight)] Frit: 30 to 60 Hydrophilic mineral oil: 2 to 10 Polyethylene glycol: 10 to 30 Water: 5 to 10 Pigment: 0 to 30

A method for producing an antibacterial porcelain according to the present invention using a liquid containing such an antibacterial metal and / or a compound of the antibacterial metal (hereinafter, referred to as “antibacterial metal-containing liquid”) is as follows. Specifically, the following method can be used. I. After the antibacterial metal-containing liquid is attached to the surface of the green body molded body, firing is performed. II A glaze layer is formed on the surface of the green body, and an antibacterial metal-containing liquid is applied to the surface of the glaze layer and then fired. III A glaze layer is formed on the surface of the green body and fired. An antibacterial metal-containing liquid is applied to the surface of the glaze layer and fired. IV Bake after attaching an antibacterial metal-containing liquid to the surface of the fired element. A glaze layer is formed on the surface of the sintered body, and an antibacterial metal-containing liquid is applied to the surface of the glaze layer, followed by firing. VI A glaze layer is formed on the surface of the fired green body and fired. An antimicrobial metal-containing liquid is applied to the surface of the glaze layer and fired.

In the present invention, among these methods, it is particularly preferable to adopt the method of II, V, VI and the like.

The sintering temperature after adhering the antibacterial metal-containing liquid is 110
0-1250 degreeC is preferable. This firing can be performed using various kilns such as a roller hearth kiln and a tunnel kiln.

After the firing, the surface is cooled to 100 ° C. or lower, preferably to room temperature, and then the surface of the glaze layer of the ceramic is irradiated with energy rays. Examples of the energy ray include UV (ultraviolet light), visible light, IR (infrared light), and microwave.
Particularly preferred are laser beams, especially carbon dioxide laser beams or YAG laser beams, especially carbon dioxide laser beams. The irradiation energy density of the laser beam is preferably about 0.01 to 3.00 W · min / cm ² .

The antibacterial activity of the glaze layer is significantly improved by such energy ray irradiation. Although this mechanism is not fully understood, ionization of an antibacterial metal such as elemental Ag or ceramic (or glaze layer) of an antibacterial metal such as Ag is performed.
It is presumed to be caused by diffusion to the outermost surface.

In the present invention, after irradiating the energy ray in this manner, the surface of the ceramic may be further treated with a water repellent to form a water repellent layer while exposing the antibacterial metal. Thereby, together with the antibacterial performance, a dirt adhesion preventing effect can be obtained.

In this water repellent treatment method, a very thin water repellent film is formed on the surface of the ceramic by spraying or applying a water repellent such as a silane compound. Since the water repellent does not bind to the antibacterial metal, which is an antibacterial component, by wiping and removing it, a water repellent layer having the antibacterial metal exposed on the surface can be formed. For example, it is possible to obtain a ceramic having the antibacterial performance of the exposed antibacterial metal and having a water repellency and an excellent effect of preventing the adhesion of dirt.

Examples of the silane compound as a water repellent include:
R-Si-X (R is a hydrophobic group such as an alkyl group or a fluoroalkyl group, and X is a substituent such as a halogen or an alkoxyl group). Silanol groups (-Si-OH) existing on the surface of the ceramics are combined and condensed to form a polysiloxane layer, and hydrophobic groups such as alkyl groups and fluoroalkyl groups exhibit good water repellency. In the case where the water repellent is an alkylsilane-based material, it is applied and then cured at room temperature to obtain a water repellent layer. When the water repellent is a fluoroalkyl silane-based material, it is baked at a temperature of about 200 to 300 ° C. after application. Thereby, a strong water-repellent layer having excellent durability can be formed.

[0028]

The present invention will be described more specifically below with reference to examples and comparative examples.

Examples 1 to 3 As a substrate to which an antimicrobial metal-containing liquid is adhered, 100 × 10
A 0 mm tile green body (unfired) was used.

As the antimicrobial metal-containing liquid, a glaze having the following composition was used, and spraying was performed to obtain 0.2 g /
Glazed at a rate of cm ² . Feldspar 53.7% by weight Silica sand 9.8% by weight Lime 12.3% by weight Dolomite 4.8% by weight Frog-eye 5.1% by weight Zinc flower 2.0% by weight Zircon 10.1% by weight Frit 2.2% by weight 0.2% by weight of silver oxide

After drying, the temperature is set to 1210 ° C. in a tunnel kiln.
And fired. After cooling to room temperature, carbon dioxide laser beam
(Output 15W) and illuminate at the next irradiation energy density
Fired. Example 1 0.18 W · min / cm²  Example 2 0.23 W · min / cm²  Example 3 0.28 W · min / cm²

The antibacterial properties of the obtained antibacterial tiles were examined in accordance with the following antibacterial test method, and the results are shown in Table 1.

[Test method for antibacterial activity] Culture of test bacteria: (1) The test bacteria (Staphylococcus aureus) were transplanted in an NA medium (normal agar medium) and cultured at a temperature of 35 to 37 ° C for 16 to 24 hours. Each culture).

(2) The bacterium pre-cultured in (1) above is replaced with N
One platinum loop was transplanted to A medium, and the temperature was 35-37 ° C and 16-2.
The cells were cultured for 0 hours (pre-culture).

Type of inoculum: NB medium (normal bouillon medium) was diluted 500-fold with phosphate buffer to adjust the pH to 7.0 ± 0.2 to form “1 / 500NB medium”. The pre-cultured bacteria were uniformly dispersed to obtain a bacterial solution for inoculation.

Preparation of Test Pieces: (1) The whole surface of three test sample tiles is lightly wiped with a gauze or a cotton wool soaked with ethanol 2-3 times and then dried (pre-treatment).

Test operation: Each of the test tiles (3 pieces) was placed in a sterile petri dish, and the test surface was inoculated with a bacterial solution for inoculation.
4 ml (containing 1.0 to 5.0 × 10 ⁵ bacteria) was inoculated, covered with a covering film and covered with a lid.
It was stored under conditions of 5 ± 1 ° C. and a relative humidity of 90% or more.

Measurement of viable cell count: Three sterile Petri dishes are prepared, and the same amount of the inoculating bacterial liquid as that inoculated to each test tile is added, and a coating film is placed thereon. Thereafter, the bacteria adhering to the respective coated films are immediately sufficiently washed out in a Petri dish using the SCDLP medium (10 ml). The viable cell count in 1 ml of the washed liquid was measured by an agar plate culture method (cultured at a temperature of 35 ± 1 ° C. for 40 to 48 hours) using an SA medium (standard agar medium), and the average of the three viable cell counts was determined. The value was determined. The dilution at the time of measuring the number of viable bacteria was performed using sterile phosphate buffered saline.

The details of the medium are as follows.

(1) Normal bouillon medium (NB medium) Meat extract: 5.0 g Peptone: 10.0 g Sodium chloride: 5.0 g Purified water: 1,000 ml pH: 7.0-7.2 (2) Normal agar Medium (NA medium) NB medium (1) supplemented with 1.5% agar. (3) Standard agar medium (SA medium) Yeast extract: 2.5 g Tryptone: 5.0 g Glucose: 1.0 g Agar: 15.0 g Purified water: 1,000 ml pH: 7.1 ± 0.1 (4) SCDLP Medium Peptone made of casein: 17.0 g Peptone made of soybean: 3.0 g Sodium chloride: 5.0 g Potassium hydrogen phosphate: 2.5 g Glucose: 2.5 g Lecithin: 1.0 g Polysorbate 80: 7.0 g Purified water: 1 2,000 ml pH: 6.8-7.2 (5) Ethanol (purity 99% or more) (6) Phosphate buffered saline

34 g of KH ₂ PO ₄ is dissolved in 500 ml of purified water, adjusted to pH 7.2 with 1N NaOH, and made up to 1000 ml with purified water. 1.25 ml of this solution is diluted 800 times with physiological saline (0.85% NaCl) to 1000 ml.

Comparative Example 1 The same antibacterial test was performed on the same tiles as in Examples 1 to 3 except that a glaze containing no silver oxide was used, and the carbon dioxide laser beam was not irradiated. 1 is shown.

Comparative Example 2 The same antibacterial test was performed on the same tiles as in Examples 1 to 3 except that the carbon dioxide laser beam was not irradiated, and the results are shown in Table 1. The same glaze as in Examples 1 to 3 (silver oxide-containing glaze) is used.

[0044]

[Table 1]

As is clear from Table 1, in Comparative Example 1 in which the glaze contained no silver oxide, the viable cell count was 2.3 × 10 ^{6 in} 24 hours.
On the other hand, in Comparative Example 2 in which 0.2% of silver oxide was contained in the glaze, the viable cell count was 1.2 × 10 ⁵ in 24 hours, and although a certain antibacterial effect was observed, The antibacterial effect is not remarkable.

On the other hand, in Examples 1 to 3 in which the carbon dioxide laser beam was irradiated, 0.16 ×
10 ⁵ (Example 1), 0.11 × 10 ⁵ (Example 2),
0.036 × 10 ⁵ (Example 3), which is 0.7% of the viable cell count after 24 hours of Comparative Example 1 (Example 1), and 0.036 × 10 ⁵ (Example 1).
The viable cell count was reduced to 48% (Example 2) and 0.16% (Example 3), and a remarkable antibacterial effect was recognized.

[0047]

As described in detail above, according to the method for producing antibacterial porcelain of the present invention, porcelain having extremely good antibacterial properties can be easily produced. This manufacturing method can be implemented only by adding a step of irradiating a laser or the like to the conventional manufacturing method of antibacterial porcelain, so that the manufacturing cost of the antibacterial porcelain hardly increases. In particular, according to the method of the fourth aspect, a remarkably sanitary porcelain having both antibacterial properties and stain resistance is provided.

Claims (4)

[Claims] 1. A liquid material containing an antibacterial metal and / or a compound of an antibacterial metal is attached to a surface of a ceramic body or a surface of a glaze layer formed on the surface of the ceramic body, and then fired to have antibacterial properties. A method for manufacturing an antibacterial porcelain, which comprises irradiating the surface of the porcelain with energy rays after firing. 2. The method according to claim 1, wherein the antibacterial metal is silver. 3. The method according to claim 1, wherein the energy ray is a laser beam. 4. The water-repellent layer according to claim 1, wherein the surface of the ceramic is further treated with a water-repellent agent after the irradiation with the energy rays to expose the antibacterial metal. A method for producing an antibacterial porcelain.