JPH07165478A - Antimicrobial porcelain or enameled product - Google Patents

Abstract

PURPOSE:To obtain a porcelain and an enameled products capable of continuously exhibiting antimicrobial effects. CONSTITUTION:This antimicrobial porcelain or enameled product is obtained by adding an antimicrobial agent of the formula M<1>aAbM<2>2(PO4)3.nH2O (M<1> is at least one metal selected from antimicrobial metals such as silver, copper, etc.; A is at least one selected from an alkali metal, an alkaline earth metal, ammonium and hydrogen; M<2> is a tetravalent metal; n is a number satisfying 0<=n<=6; a and b are each a number satisfying la+mb=1 with the proviso that l is valence of M<1> and m is valence of A) to a surface layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a product in which antibacterial properties are imparted to a surface of a metal material or porcelain, etc., and enamel products such as bathtubs and containers or ceramic products such as tiles and sanitary ware, etc. It is useful as a ceramic product that requires antifungal properties.

[0002]

2. Description of the Related Art Luster on the surface of ceramics and metal materials,
In order to improve smoothness or corrosion resistance, it is effective to form a thin glass layer on the surface of these materials,
For this purpose, various glazes have been developed according to the characteristics of various ceramics and metal materials. A thin glass layer formed by applying glaze, that is, by applying a glaze and then baking at an appropriate temperature (called glaze baking) not only imparts smoothness or corrosion resistance to the surface of ceramics and metal materials, It contributes to improving the stain resistance of these materials and maintaining a clean surface. However, recently, there is a strong desire to suppress the generation of mold and bacteria and create a clean environment, and it has been demanded to impart antibacterial properties to ceramics and metal materials.

On the other hand, various organic polymer materials such as molding resin materials, paints, fillers and fibers should be blended, supported, or contained in the material by a method according to each purpose of use. Have developed various types of antibacterial agents capable of exerting antibacterial properties. Some antibacterial agents consist of organic compounds or inorganic compounds. Inorganic antibacterial agents are more safe than organic antibacterial agents and volatilize or decompose even when exposed to high temperature treatment. The feature is that the antibacterial effect can be maintained for a long time without doing so. In general, inorganic antibacterial agents are those in which a metal exhibiting antibacterial properties such as silver and copper is supported on an inorganic compound, and various compounds have been proposed as an inorganic compound that is a carrier, such as activated carbon and apatite ( Calcium phosphate), zirconium phosphate, phosphates such as aluminum phosphate, aluminum silicate salts such as zeolite, and silica (silicic acid) are known. Among them, the phosphate-based antibacterial agent represented by the following general formula is known to have excellent durability such as chemical resistance and weather resistance (JP-A-4-27).
5370). M ¹ _{a Ab} M ² ₂ (PO ₄ ) ₃ · nH ₂ O (M ¹ is silver, copper, zinc, tin, mercury, lead, iron, cobalt,
At least one metal ion selected from nickel, manganese, arsenic, antimony, bismuth, barium, cadmium or chromium, and A is at least one metal ion selected from alkali metal ions, alkaline earth metal ions, ammonium ions or hydrogen ions. Is an ion of M ²
Is a tetravalent metal ion, n is a number that satisfies 0 ≦ n ≦ 6, and a and b are both positive numbers that satisfy la + mb = 1. However, 1 is the valence of M ¹ and m is the valence of A. Recently, it has been proposed that a glaze containing a hydroxyapatite antibacterial agent, which is one of the inorganic antibacterial agents, is used to impart antibacterial and antifungal properties to ceramics and the like (Japanese Patent Laid-Open No. 5-2
(01747), there is still room for improvement in the antibacterial properties exhibited by the product after glaze baking.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a ceramic and an enamel product which can continuously exhibit an antibacterial effect.

[0005]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that a specific phosphoric acid having an antibacterial metal ion carried in a component constituting a conventional glaze. It has been found that the use of a salt-based antibacterial agent makes it possible to exhibit extremely excellent antibacterial properties in a glaze-baked product, and has completed the present invention.

That is, the present invention is an antibacterial ceramic or enamel product in which the antibacterial agent represented by the following general formula [1] is present in the surface layer. M ¹ _{a Ab} M ² ₂ (PO ₄ ) ₃ · nH ₂ O [1] (M ¹ is silver, copper, zinc, tin, mercury, lead, iron, cobalt,
At least one metal ion selected from nickel, manganese, arsenic, antimony, bismuth, barium, cadmium, and chromium, and A is at least one metal ion selected from alkali metal ions, alkaline earth metal ions, ammonium ions, and hydrogen ions. Is an ion of M ²
Is a tetravalent metal, n is a number satisfying 0 ≦ n ≦ 6,
Both a and b are positive numbers that satisfy la + mb = 1. However, 1 is the valence of M ¹ and m is the valence of A. )

The present invention will be described in detail below. Antibacterial Agent The antibacterial agent in the present invention is represented by the following general formula [1]. M ¹ _{a Ab} M ² ₂ (PO ₄ ) ₃ · nH ₂ O [1] (M ¹ is silver, copper, zinc, tin, mercury, lead, iron, cobalt,
At least one metal ion selected from nickel, manganese, arsenic, antimony, bismuth, barium, cadmium, and chromium, and A is at least one metal ion selected from alkali metal ions, alkaline earth metal ions, ammonium ions, and hydrogen ions. Is an ion of M ²
Is a tetravalent metal, n is a number satisfying 0 ≦ n ≦ 6,
Both a and b are positive numbers that satisfy la + mb = 1. However, 1 is the valence of M ¹ and m is the valence of A. )

The compound represented by the above general formula [1] is an amorphous compound or a crystalline compound belonging to the space group R3C, and each constituent ion forms a three-dimensional network structure. As the antibacterial agent in the present invention, a crystalline compound having a three-dimensional network structure is preferable because it has little change in physical properties due to heat. M in the above general formula [1]
^{No. 1} is known as a metal exhibiting antifungal, antibacterial and antialgal properties, and among them, silver can enhance antifungal, antibacterial and antialgal properties in addition to safety. It is particularly effective as a possible metal.

A in the above general formula [1] is at least one ion selected from alkali metal ions, alkaline earth metal ions, ammonium ions and hydrogen ions. Preferred specific examples are lithium ion and sodium ion. And alkali metal ions such as potassium ion, alkaline earth metal ions such as magnesium ion or calcium ion or hydrogen ion, and among these, potassium ion, sodium ion and hydrogen ion from the viewpoint of stability of the compound and availability at low cost. Ions are the preferred ions.

M ² in the above general formula [1] is a tetravalent metal ion, and preferred specific examples thereof are zirconium ion, titanium ion or tin ion. Considering the safety of the compound, zirconium ion and titanium ion are considered. Ions are a particularly preferred tetravalent metal.

The following are specific examples of the antibacterial agent represented by the above general formula [1]. Ag _0.005 Li _0.995 Zr ₂ (PO ₄ ) ₃ Ag _0.01 (NH ₄ ) _0.99 Zr ₂ (PO ₄ ) ₃ Ag _0.05 Na _0.95 Zr ₂ (PO ₄ ) ₃ Ag _0.2 K _0.8 Ti ₂ (PO ₄ ) ₃ Ag _0.1 H _0.9 Zr ₂ (PO ₄ ) ₃ Ag _0.05 H _0.05 Na _0.90 Zr ₂ (PO ₄ ) ₃ Ag _0.05 H _0.55 Na _0.40 Zr ₂ (PO ₄ ) _{3 The} same as the charge amount of silver ion per mol of the above compound Ag in each of the above equations while maintaining the charge amount
There is a compound in which is substituted with Zn, Mn, Ni, Pb, Hg, Sn, or Cu.

Methods for synthesizing the antibacterial agent used in the present invention include a calcination method, a wet method and a hydrothermal method, which can be easily obtained, for example, as follows.・ Synthesis of network structure phosphate When synthesized by a firing method, a compound containing an alkali metal ion such as lithium carbonate (Li ₂ CO ₃ ) or sodium carbonate (Na ₂ CO ₃ ), zirconium oxide (ZrO ₂ ) etc. The compound containing zirconium and the compound containing a phosphate group such as ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ) are mixed at a molar ratio of about 1: 4: 6, ~ 1400
The compound represented by the general formula [2] is obtained by baking at a temperature of ℃. A ′ _x Zr ₂ (PO ₄ ) ₃ [2] (A ′ is at least one metal ion selected from an alkali metal ion, an alkaline earth metal ion or an ammonium ion, and x is a monovalent A ′. When it is 1, it is 1/2, and when A is divalent, it is 1/2) By immersing this in an aqueous solution containing silver ions at an appropriate concentration at room temperature to 100 ° C., the general formula [1 ] The antibacterial agent shown by this is obtained. The compound in which the A ion in the general formula [1] is a hydrogen ion is obtained by immersing the compound represented by the general formula [2] in an aqueous solution of an inorganic acid such as nitric acid, sulfuric acid and hydrochloric acid at room temperature to 100 ° C. Therefore, the general formula H _{(1-z) A'z} M ₂ (PO ₄ ) ₃ (z is 0
Alternatively, the compound [3] represented by the formula (1) or less) is obtained and further immersed in an aqueous solution containing silver ions at an appropriate concentration to obtain the antibacterial agent represented by the general formula [1].

Further, in the case of synthesizing by a wet method, oxalic acid and phosphoric acid are added to the zirconium oxychloride aqueous solution while stirring. The pH of the reaction solution was adjusted to 3 with a caustic soda solution, heated under reflux for 10 hours,
The precipitate is filtered, washed with water, dried and pulverized to obtain reticulated zirconium phosphate [NaZr ₂ (PO ₄ ) ₃ ]. The antibacterial agent represented by the general formula [1] is obtained by immersing this in an aqueous solution containing an antibacterial metal ion at an appropriate concentration.

In order to obtain an antibacterial agent having extremely excellent antibacterial properties and heat resistance, the tetravalent metal salt of phosphoric acid synthesized by the wet method is loaded with hydrogen ions together with antibacterial metal ions and then baked. Is preferred. When the tetravalent metal phosphate salt has an ammonium ion, the ammonium ion is thermally decomposed by baking to leave a hydrogen ion, so that the tetravalent metal phosphate salt does not need to carry the hydrogen ion. On the other hand, when the tetravalent metal phosphate has no or only a very small amount of ammonium ion, a method of allowing the tetravalent metal phosphate to carry hydrogen ions is to immerse it in an acidic solution. As a preferred specific example of the acidic solution, hydrochloric acid,
There are aqueous solutions of sulfuric acid, nitric acid, etc. The acid concentration, temperature, and immersion time of the acidic solution are not particularly limited, but in general, the higher the acid concentration, the more quickly hydrogen ions can be supported, so the preferred acid concentration is 0.1 N or more, and The treatment temperature is 40 ° C or higher, more preferably 60 ° C to 1
The temperature is 00 ° C., and the immersion time is 10 minutes or longer, more preferably 60 minutes or longer.

The baking step may be carried out after supporting the antibacterial metal ion and the hydrogen ion or the ammonium ion on the tetravalent metal phosphate to improve the chemical and physical stability of the antibacterial agent. To obtain. The firing temperature is 500 to 1300 ° C, preferably 600 to 100
It is preferable to control the firing within the range of 0 ° C. Baking at a temperature of less than 500 ° C is insufficient to improve the chemical and physical stability of the antibacterial agent, while baking at a temperature of 1300 ° C or more results in a slight decrease in the antibacterial property, or fine particles of phosphoric acid. There is a possibility that the tetravalent metal salt may be fused and a fine particle antibacterial agent may not be obtained. The firing time is not particularly limited, and a sufficient effect is usually obtained by firing for 1 to 20 hours. The rate of temperature increase and the rate of temperature decrease are not particularly limited, and can be appropriately adjusted in consideration of the capacity and productivity of the firing furnace.

In order to exhibit antifungal, antibacterial and antialgal properties, the larger the value of a in the general formula [1] is, the better.
When the value of a is 0.001 or more, it is possible to sufficiently exhibit antifungal properties and antibacterial properties and antialgal properties. However, if the value of a is less than 0.01, it may be difficult to exert antifungal, antibacterial and antialgal properties for a long time.
The value of a is preferably 0.01 or more. or,
Considering economy, the value of a is suitably 0.5 or less. The preferable particle size of the antibacterial agent in the present invention is 0.1 to 0.1.
It is 10 μm. If it is smaller than 0.1 μm, agglomeration may occur during storage and it may be difficult to uniformly disperse it in the glaze, while if it is larger than 10 μm, roughness may occur on the surface after glaze baking, Since the antibacterial agent is likely to settle, it may not be possible to uniformly disperse the antibacterial agent and apply glaze.

The antibacterial agent of the present invention is extremely stable against exposure to heat and light, its structure and composition do not change even after heating at 800 ° C. to 1300 ° C., and even when it is irradiated with ultraviolet rays, it has no effect. Does not cause discoloration. Further, the phosphate in the present invention does not come into contact with water in a liquid state, and the skeleton structure does not change even in an acidic solution. Therefore, the porcelain and enamel products baked glaze containing the above phosphate-based antibacterial agent, very few restrictions on the use environment, even when contacted with an acidic solution does not reduce the antibacterial effect, The antibacterial effect can be continuously exerted.

○ Glaze The ingredient of the glaze containing the antibacterial agent in the present invention is applied to the surface of a ceramic or a metal material, and baked,
In order to form a thin glass layer by adhering to the surface to be coated,
Any of the glaze components conventionally used can be used. Generally, a glaze is prepared as a suspension obtained by adding a colloidal component such as frit and kaolin that have been vitrified through a melting process, crushing them and adding water thereto. Specific examples of the glaze include the following. That is, transparent Yu, color Yu, crystal Yu, Kiryu Yu,
Salt Yu, Pottery Yu, Stoneware Yu, Porcelain Yu, Alkaline Glaze, Feldspar Yu, Lime Yu, Lead Glaze, Boric Acid Glaze, Frit Glaze,
Tin enamel, Bristol glaze, color Bristol glaze, Aventurine glaze, green lead glaze, Rockingham glaze, Zegel porcelain glaze,
Examples include gloss glaze, matte glaze, emulsion glaze, colored porcelain glaze, and the like. or,
There is a glaze used for the following enamels. That is, iron enamel, aluminum enamel, stainless steel enamel, copper enamel, silver enamel, gold enamel, molybdenum enamel and the like.

These glazes include tin oxide, antimony oxide, zinc oxide, germanium oxide, manganese oxide, chromium oxide, iridium oxide, iron oxide, platinum oxide as colorants.
Coloring by adding metal oxides such as nickel oxide, cobalt oxide, copper oxide, uranium oxide, diantimony trioxide, titanium oxide, zirconium oxide, phosphorous acid, rutile chromate, gold chloride and colored clay. You can The preferred mixing ratio of these colorants is from 1 to 50 parts per 100 parts by weight of the solid content of the glaze (hereinafter simply referred to as "parts"). Further, in order to improve the adhesion with metal and the fire resistance, cobalt oxide, nickel oxide, manganese oxide, molybdenum oxide, aluminum oxide, chromium oxide, etc. are added to the glaze solid content 10
5 to 50 parts may be added per 0 part, or citric acid or sodium nitrite may be added in an amount of 1 part or less in order to improve the coating property.

○ Blending Method As a blending method of the antibacterial agent to the glaze, any known method can be adopted. For example, a method of adding to the raw powder of glaze and mixing with a mill, a method of adding to the already prepared glaze and mixing with a mixer, after applying the glaze to the desired material surface, suspending it in a dispersion medium such as water Another example is a method in which the slurry antibacterial agent is sprayed onto the antibacterial agent. In order to exert the effect with as little antibacterial agent as possible, after applying a glaze that does not contain an antibacterial agent, spray the antibacterial agent on the desired surface to impart antibacterial properties, or apply a lower glaze. It is advisable to apply a thin layer of top glaze containing an antibacterial agent on the surface.

The preferred blending ratio of the antibacterial agent is 0.1 to 20% by weight per 100 parts by weight of the antibacterial glaze excluding water when mixed with the glaze, and the glaze containing no antibacterial agent is applied. When applied later, the amount of antibacterial agent applied is
It is 0.01 to 1 g / m ² . If the blending ratio or the coating amount of the antibacterial agent is too small, it becomes difficult to exert sufficient antibacterial property, and even if it is added unnecessarily, the antibacterial property is not improved so much and other antiglare There is a risk of deteriorating the physical properties.

Processing method Any known method can be adopted for the glazing, glaze firing, base treatment method and the like. For example, the firing method is climbing kiln, falling flame type round kiln,
Examples include kiln firing and flame spraying using a muffle kiln or tunnel kiln. Further, the preferable firing temperature is 700 to 14
The temperature is 50 ° C., and the firing conditions may be appropriately set depending on the material, the type of glaze, the kiln used, and the like.

In the antibacterial glaze thus obtained, the inorganic antibacterial agent, which is a component thereof, has excellent chemical and physical stability, so that the antibacterial glaze on the surface of ceramics and metal materials. In addition to imparting the above, the product itself has excellent safety and processability, and in addition, it does not deteriorate when the antibacterial agent and the glaze are mixed and when the antibacterial product is subsequently used, and in a severe environment. It has antifungal, antibacterial and antialgal properties for a long time.

Object to which antibacterial glaze is applied The above antibacterial glaze is useful for producing various pottery or enamel products that require antifungal, algae or antibacterial properties. Specific applicable objects include, for example, toilet bowls, hand washbasins, washbasins, washing machines, sanitary ware such as bathtubs, various ornaments,
Tableware, bone china, exterior, floor, porcelain such as tiles,
Brick, earthen pipes, tiles and other earthenware, terra cutter, interior tiles, floor tiles and other stoneware, heat exchangers, household heat appliances, brewing tanks, tableware, aircraft parts, automobile parts, ship parts, and other metal products. Can be mentioned.

Hereinafter, the present invention will be described in more detail with reference to Examples.

[Reference Example 1] (Preparation of zirconium phosphate antibacterial agent) An aqueous solution of zirconium sulfate and an aqueous solution of phosphoric acid were mixed so that the atomic ratio of zirconium and phosphorus was 2: 3 to form a precipitate. The pH was adjusted to 2 using an aqueous solution of sodium hydroxide, and then heated at 130 ° C. under a saturated steam pressure for 12 hours to obtain crystalline zirconium phosphate [NaZr ₂ (PO ₄ ) ₃ ]. The phosphate compound obtained above was thoroughly washed with water, added to silver nitrate and a 1N aqueous nitric acid solution, stirred at 60 ° C. for 4 hours, then thoroughly washed with water and dried. This was baked in a baking furnace at 750 ° C for 4 hours and then lightly crushed to give an antibacterial agent [compositional formula: A
g _0.17 Na _0.29 H _0.54 Zr ₂ (PO ₄ ) ₃ , silver loading: 3.6 wt%] was obtained. The obtained antibacterial agent is 0.72.
It was a white powder with an average particle size of micron.

[0026]

[Reference Example 2] (Preparation of hydroxyapatite antibacterial agent) 80 g / l phosphoric acid was added dropwise to a 37 g / l calcium hydroxide suspension, and these were reacted to obtain hydroxyapatite, and the pH was adjusted to 6. After that, silver nitrate was further added at a ratio of 5.7 parts per 100 parts of hydroxyapatite,
Silver was supported on hydroxyapatite. Obtained hydroxyapatite antibacterial agent (amount of silver carried: 3.6 wt
%) Was thoroughly washed with water and then dried.

[0027]

Example 1 10 parts of the zirconium phosphate antibacterial agent obtained in Reference Example 1 was added to 100 parts of a frit having the following composition:
Aluminum oxide 25 parts, clay 10 parts, cobalt oxide 1
Parts, 0.05 parts citric acid, and 50 parts water, and uniformly mixing these to obtain a slurry, which is applied to a stainless steel plate,
After drying, it was baked at 1000 ° C. to obtain an enamel-treated stainless plate (Sample 1). (Composition of the frit) SiO _2: 49.2 parts of Al ₂ O _3: 7.7 parts of B ₂ O _3: 17.4 parts of CaO: 2.9 parts K ₂ O: 4.5 parts Na ₂ O: 15. 2 parts F: 0.04 part NiO: 0.7 part CoO: 0.6 part MnO ₂ : 1.4 part

[0028]

[Comparative Example 1] The same treatment as in Example 1 was carried out except that the hydroxyapatite antibacterial agent obtained in Reference Example 2 was used in place of the zirconium phosphate antibacterial agent to obtain an enamel-treated stainless plate ( Comparative sample 1).

[0029]

Comparative Example 2 An enamel-treated stainless plate was obtained by performing the same treatment as in Example 1 except that the antibacterial agent was not added (Comparative Sample 2).

[0030]

Example 2 A transparent glaze containing 3 parts of the zirconium phosphate antibacterial agent obtained in Reference Example 1 was applied to a pottery to 1000
Firing was performed at 0 ° C. to obtain a pottery having an antibacterial glaze on its surface (Sample 2).

[0031]

[Example 3] A transparent glaze containing no antibacterial agent was used in Example 2
After applying to a ceramic in the same manner as above, 0.1 g / m ^{2 of a} 0.1 wt% slurry of the zirconium phosphate antibacterial agent obtained in Reference Example 1 was applied to the surface by a sprayer, and 1
Firing was performed at 000 ° C. to obtain a pottery in which an antibacterial agent was present in the surface layer on the surface (Sample 3).

[0032]

Comparative Example 3 A glazed pottery was obtained in the same manner as in Example 2 except that the antibacterial agent was not mixed with the glaze (Comparative Sample 3).

(Evaluation Method of Antibacterial Property) The antibacterial activity of the enamel or ceramics produced in the above Examples and Comparative Examples was evaluated by the following method. That is, Escherichia coli was used as a test bacterium, and a stainless steel plate and a pottery, which were baked with a glaze, were cut into 3 cm × 3 cm to obtain test pieces. The bacterial solution was uniformly inoculated on the surface so that the number of bacteria per test piece would be 10 ⁴ to 10 ⁵ and stored at 27 ° C. After storage for 3 hours from the start of storage, surviving bacteria on the test piece were washed out with a medium for measuring the number of bacteria (SCDLP liquid medium), and this washing solution was used as a test solution. For this test solution,
The number of viable bacteria was measured by the pour plate culture method (37 ° C for 2 days) using a culture medium for measuring the number of enamel or pottery 3 cm x
It was converted to the viable cell count per 3 cm. The results of the antibacterial test obtained as described above are shown in Table 1 below. The initial number of bacteria in the antibacterial test was 7.1 × 10 ⁴ , and the number of control bacteria (the number of bacteria after storing the bacterial solution in a petri dish at 27 ° C for 3 hours) was 6.8 × 10 ⁴ . there were.

[0034]

[Table 1]

[0035]

INDUSTRIAL APPLICABILITY Since the ceramic or enamel product of the present invention has an antibacterial agent having extremely excellent durability in the surface layer, excellent antibacterial property can be continuously exhibited.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location C23D 5/00 J (72) Inventor Hideki Kato 1 East of 1 Funami-cho, Minato-ku, Nagoya-shi, Aichi Inside the Nagoya Research Institute, Ago Synthetic Chemical Industry Co., Ltd.

Claims (1)

[Claims] 1. An antibacterial ceramic or enamel product in which an antibacterial agent represented by the following general formula [1] is present in a surface layer. M ¹ _{a Ab} M ² ₂ (PO ₄ ) ₃ · nH ₂ O [1] (M ¹ is silver, copper, zinc, tin, mercury, lead, iron, cobalt,
At least one metal ion selected from nickel, manganese, arsenic, antimony, bismuth, barium, cadmium, and chromium, and A is at least one metal ion selected from alkali metal ions, alkaline earth metal ions, ammonium ions, and hydrogen ions. Is an ion of M ²
Is a tetravalent metal ion, n is a number that satisfies 0 ≦ n ≦ 6, and a and b are both positive numbers that satisfy la + mb = 1. However, 1 is the valence of M ¹ and m is the valence of A. )