JPH09249511A - Antimicrobial agent and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antimicrobial agent usable for sterilizing and disinfecting drinking water, suppressing proliferation of underwater algae, preventing occurrence of molds on resin products, etc. SOLUTION: Powder of a silver compound is stuck to the surface of a carrier and baked to produce the objective antimicrobial agent having a coated film of silver. An inorganic carrier (silicic acid, aluminum silicate, zeolite, alumina, sand, glass, etc.) and an organic carrier (Teflon, silicon, bakelite, etc.) are used and the one neither decomposing nor melting at the baking mperature is preferable. The shape of the carrier is more preferably one having unevenness on the surface due to the ready adhesion of the silver compound. Silver oxide, silver carbonate, silver protein, etc., may be cited as the powder of the silver compound. Silver oxide and/or silver carbonate excellent in adhesivity to the carrier is preferably used. The particle size of the powder of the silver compound is especially preferably <=1μm. The powder of the silver compound is stuck to the carrier, baked at 400-1,000 deg.C and thermally reduced to produce the antimicrobial agent forming a coated film of silver on the surface of the carrier.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an antibacterial agent and a method for producing the same.

[0002]

2. Description of the Related Art Synthetic resin products are widely used for kitchen appliances, bathroom appliances, etc., but they are often exposed to moisture, and mold is likely to occur on their surfaces. There was a problem that it was not only unpleasant but also unsanitary. In addition, household water purifiers that use activated carbon as a filter medium are becoming widespread due to health consciousness in recent years, but since chlorine components in tap water are removed by activated carbon, they remain in the water purifier. There is a problem that bacteria and mold easily grow in tap water (purified water). In view of such a problem, antibacterial treatment has been started to be applied to products and the like, which are prone to germs and molds and proliferate, by using antibacterial agents.

As an antibacterial agent of this type, a water-soluble silver supported by, for example, immersing a porous carrier in an aqueous solution of a water-soluble silver compound such as silver nitrate to adsorb and carry the silver compound on the carrier, and then subjecting it to alkali treatment. It was known that the compound was changed to an insoluble or sparingly soluble silver compound, but with the problem that it was difficult to maintain sufficient antibacterial property for a long period of time, the silver compound was only adsorbed and supported on the porous carrier. In these antibacterial agents, when silver nitrate was used as the water-soluble silver compound, toxic nitrate ions might be eluted. Instead of such an antibacterial agent, an antibacterial agent in which a porous carrier is immersed in an aqueous solution of silver oxide to adsorb and carry silver oxide on the carrier has been proposed (Japanese Patent Laid-Open No. 51-7121). However, it is difficult to dissolve a large amount of silver oxide in water at once like silver nitrate,
Therefore, when trying to adsorb and support a large amount of silver oxide on the carrier, the carrier has to be immersed in a solution containing silver oxide for a long time, resulting in a problem that the production efficiency is extremely poor. Further, silver oxide can be adsorbed and supported from an aqueous solution on a porous carrier, but there is a problem that it is hardly supported on a non-porous carrier.

Further, a method of obtaining an antibacterial agent by immersing the carrier in an aqueous solution of a water-soluble silver compound and then firing it has been proposed (for example, JP-A-5-58829 and JP-A-6-877).
No. 11, etc.). However, in these methods, although the silver compound can be uniformly adsorbed and supported on the surface of the carrier,
There is a limit to the amount of silver compound that can be adsorbed and supported on the carrier in one treatment, and when trying to support a large amount of silver compound, it was necessary to repeat the operation of immersing the carrier in an aqueous solution of the silver compound and baking it. .

On the other hand, it is known that a silver coating is formed on the surface of a carrier by utilizing a vapor deposition method or a silver mirror reaction. In this method, it is easy to increase the effective amount of silver supported on the carrier, The former has a problem that it requires a special device for manufacturing, and the latter uses silver nitrate and ammonia that are specified as deleterious substances in the manufacturing process, so the waste liquid used for manufacturing must be safely treated. was there.

In order to solve the above problems, the present inventors have tried a method of depositing silver powder on a carrier and then firing it to form a silver coating on the surface of the carrier. However, as a result, a sufficient amount of silver could not be supported on the carrier, and only an antibacterial agent having a poor antibacterial effect was obtained. Further, in order to form a silver coating on the surface by adhering silver powder to a carrier and baking, it is necessary to bake at a high temperature of 900 ° C. or higher, which requires a large amount of energy for baking, and depending on the type of carrier. There is a problem that it decomposes or melts during firing. The present inventors, in view of such problems, as a result of further diligent research,
When a silver compound powder is used instead of the silver powder, it is possible to attach a large amount of powder to the carrier, which is unpredictable from the case of using the silver powder, and as a result, the effective amount of silver supported on the carrier is increased. The present invention has been completed, finding that it can be increased and that a silver coating can be formed on the surface of a carrier by firing at a much lower temperature than in the case of silver powder.

[0007]

That is, the antibacterial agent of the present invention comprises:
It is characterized in that it has a silver coating formed on the surface of a carrier by firing a silver compound powder adhered to the surface of the carrier. Further, the method for producing an antibacterial agent of the present invention is characterized in that after a silver compound powder is attached to the surface of a carrier, it is baked to form a silver film on the surface of the carrier. The powdery silver compound used in the production method of the present invention is preferably silver oxide powder and / or silver carbonate powder.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as the carrier, either an inorganic carrier or an organic carrier can be used.
Those that do not decompose or dissolve at a temperature of ℃ or above are preferable, and those that do not decompose or dissolve at the firing temperature are particularly preferable. Examples of preferable inorganic carriers include silicic acid, aluminum silicate, zeolite, alumina, sand, glass and the like. Examples of preferable organic carriers include Teflon,
Examples thereof include heat resistant resins such as silicon and bakelite, and thermosetting resins. The shape of these carriers may be, for example, powdery, spherical, plate-like, fibrous, or the like, but those having fine irregularities on the surface are more preferable because the silver compound powder is easily attached. . Therefore, for example, when glass spheres are used as the carrier, it is preferable to use those having a surface provided with surface irregularities by putting a pickpocket on the surface. When the carrier is powdery or spherical, the particle size of the carrier can be appropriately selected according to the purpose of use.

As the silver compound powder, silver oxide, silver carbonate,
Fatty acid silver (silver acetate, silver benzoate, etc.), protein silver and the like can be mentioned. These can be used as a mixture of two or more kinds, but silver oxide and / or silver carbonate having good adhesion to a carrier can be used. It is preferable to use. The particle size of silver compound powder is 1
00μ or less is preferable, and 1μ or less is particularly preferable.

Examples of the method for adhering the silver compound powder to the carrier include a method in which the carrier and the silver compound powder are put in a container and shaken to adhere, and a method using a mixing machine such as a kneader. The amount of the silver compound powder adhered to the carrier is preferably 0.1% by weight or more of the weight of the carrier, and particularly when long-term sustainability is required, the amount adhered is 10% by weight of the carrier weight. It is preferable to set it as above. The antibacterial agent obtained by the method of the present invention has the advantage that the effective amount of silver supported on the carrier is high,
When it is desired to further increase the effective amount of silver supported on the carrier, a method of repeating the treatment of depositing the silver compound powder on the carrier and baking, or when depositing the silver compound powder on the carrier is used. It is preferable to adopt a method of using a liquid such as glycerin as a binder.

After depositing the silver compound powder on the carrier, the silver compound powder is thermally reduced by baking it to form a silver film on the surface of the carrier, whereby the antibacterial agent of the present invention is obtained.
The firing temperature is preferably 150 ° C or higher, more preferably 400 ° C or higher. However, depending on the type of carrier, there is a risk of decomposition or dissolution when baked at a high temperature, so the baking temperature is preferably 400 ° C to 1000 ° C. still,
When a porous substance is used as the carrier in the present invention, the silver coating may be formed not only on the surface of the carrier but also in the pores of the porous carrier.

The antibacterial agent of the present invention can be used for sterilizing and disinfecting drinking water, suppressing the growth of algae in water, preventing the formation of mold and the like on resin products, preventing sticking of barnacles to ship bottoms, and preventing contamination by dog and cat excrement. Although it can be used for any purpose, it is not limited to the above-mentioned applications, as long as it can kill bacteria, bacteria, fungi, microorganisms and the like, and prevent the generation and growth of the bacteria.

In order to treat water with the antibacterial agent of the present invention, for example, a method of passing water through a column packed with the antibacterial agent of the present invention or immersing the antibacterial agent of the present invention in water can be mentioned. When used in a household water purifier or the like, a method of arranging a layer of the antibacterial agent of the present invention together with a layer of activated carbon or a method of mixing the activated carbon and the antibacterial agent of the present invention to use can be adopted.

In order to further treat the resin product, a method of kneading the antibacterial agent of the present invention into the raw material resin can be adopted. The resin into which the antibacterial agent is kneaded may be any resin having plasticity, and examples thereof include polyethylene, polypropylene, polystyrene, ABS resin, polyvinyl chloride, MMA resin and the like. The amount of antibacterial agent added to the resin is arbitrary,
It is determined in consideration of kneading efficiency, antibacterial performance, resin strength and the like. The resin in which the antibacterial agent is kneaded can be molded into any shape such as spherical shape, pellet shape, plate shape, sheet shape, and fiber shape. For example, in the case of molding into a plate shape, a sheet shape, or a fibrous shape, an antibacterial agent and a resin are premixed, kneaded in a kneader such as an extruder at a temperature equal to or higher than the softening temperature of the resin, and then a sheet shape from a die or the like. It may be extruded into a plate shape, a fiber shape or the like. In addition, the spherical or pellet resin in which the antibacterial agent is kneaded can be made into an antibacterial resin product having a predetermined shape by injection molding or the like. Further, after applying the antibacterial agent of the present invention on the surface of a resin product, the antibacterial resin product can be obtained by a method of heat pressing the applied surface.

When the antibacterial agent of the present invention is added to a paint such as a ship bottom paint, it can be used as an antibacterial paint for imparting antibacterial property to the surface to which the paint is applied. The paint may be oily or water based. When the antibacterial agent of the present invention is added to the paint, it may be blended and dispersed in the same manner as the pigment. However, the antibacterial agent of the present invention is not limited to the case of being added to the paint, and is added to the paint diluent. It can also be used.

The antibacterial agent of the present invention can be used by polishing the surface, if necessary. When the surface of the antibacterial agent of the present invention is polished, it has a beautiful metallic luster appearance. Therefore, it is suitable for use for a purpose that also has a decorative purpose, such as being used as an algae preventative agent for aquariums for ornamental fish. Is.

[0017]

The present invention will be described below in further detail with reference to examples and comparative examples. The antibacterial agents used in Examples and Comparative Examples were produced as follows.

Antibacterial agent A (product of the present invention) 100 parts by weight of alumina spheres (particle size: 3 mm) and 5 parts by weight of silver oxide powder (particle size: 1 μ or less) are put in a polyethylene container and mixed to form silver oxide on the alumina spheres. The powder was deposited. Then, it was baked at 800 ° C. for 2 hours.

Antibacterial agent B (product of the present invention) To 100 parts by weight of glass spheres (particle diameter: 2 mm) containing surface abrasion,
2 parts by weight of silver oxide powder (particle size 1 μm or less) was put into a polyethylene container and mixed, the silver oxide powder was adhered to glass spheres, and then baked at 400 ° C. for 4 hours.

Antibacterial agent C (product of the present invention) 100 parts by weight of sea sand and 3 parts by weight of silver carbonate powder (particle size 1 μm or less) were put in a polyethylene container and mixed, and silver carbonate powder was adhered to the sea sand. It was baked at 1000 ° C. for 2 hours.

Antibacterial agent D (product of the present invention) 100 parts by weight of zeolite (average particle size of 10 μm or less) and 5 parts by weight of silver oxide powder are put in a polyethylene container and mixed, and silver oxide powder is adhered to the zeolite. , 400 ° C
It was baked for 8 hours.

Antibacterial agent E (product of the present invention) 100 parts by weight of silicic acid powder (average particle size of 5 μ or less) and 3 parts by weight of silver oxide powder are put in a polyethylene container and mixed, and the silver oxide powder is attached to the silicic acid powder. After that, it was baked at 500 ° C. for 4 hours.

Antibacterial agent F (comparative) After immersing 100 parts by weight of silicic acid powder (average particle size 5 μm or less) in 200 parts by weight of a 5% silver nitrate aqueous solution for 24 hours, the carrier was taken out from the silver nitrate aqueous solution and nitrate ions were added. Concentration is 1
It was washed with deionized water until it became less than ppm. Then 1
After drying at 00 ° C. for 5 hours, it was baked at 800 ° C. for 2 hours.

Antibacterial agent G (comparative product) 5 parts by weight of silver oxide was added to 500 parts by weight of water and stirred for 3 hours, and 100 parts by weight of glass beads (particle diameter: 2 mm or less) with surface-powders were immersed in this solution. Then, the glass spheres were taken out from the silver oxide aqueous solution and dried at 100 ° C. for 5 hours, and then 4
It was baked at 00 ° C. for 4 hours.

Antibacterial agent H (comparative product) 100 parts by weight of the same carrier as the antibacterial agent A and an average particle size of about 50
5 parts by weight of silver powder of μ was put in a polyethylene container and mixed, and then the carrier was taken out.
Fired for hours.

Examples 1 to 3 and Comparative Examples 1 and 2 10 g of the antibacterial agent shown in Table 1 was packed in a stainless steel column having an inner diameter of 2 cm, and tap water was continuously passed through this column at 200 ml / min, and after 1 day. The silver ion concentration in the water flow solution after 10 days and 20 days was measured by atomic absorption spectrometry. Table 1 shows the obtained results.

[0027]

[Table 1]

Examples 4 to 5 and Comparative Example 3 After 2 g of the antibacterial agent shown in Table 2 was kneaded into 100 g of ABS resin, a plate plate of 60 mm × 40 mm × 3 mm was molded using a molding machine. Then E. coli dispersion (5 x 10 ⁵
The plate plate formed by kneading the above-mentioned antibacterial agent into 200 g of cells / ml) was immersed and contacted with shaking for 24 hours, and the change with time of the viable cell count in the Escherichia coli dispersion was examined. Table 2 shows the results.

[0029]

[Table 2]

[0030]

As described above, the antibacterial agent of the present invention is
Since the carrier on which the silver compound powder is adhered is baked to form a silver coating on the surface of the carrier, the effective amount of silver supported on the carrier can be sufficiently increased, and the silver compound can be added to the carrier. A high antibacterial effect can be maintained for a long period of time as compared with conventional antibacterial agents that are adsorbed or supported. Further, in the method of the present invention, the powder of the silver compound is adhered to the carrier and baked to form a silver coating. Therefore, according to the method of the present invention, the carrier is immersed in an aqueous solution of the silver compound and then baked. As compared with the conventional antibacterial agent obtained by the method, an antibacterial agent having a large amount of silver supported can be obtained. Moreover, according to the method of the present invention, a silver coating can be formed on the surface of a carrier by a simple manufacturing operation, and an antibacterial agent having a silver coating can be produced more easily and cheaply as compared with a method of forming a silver coating by utilizing vapor deposition or silver mirror reaction. . In addition, there are various advantages such that the number of kinds of chemicals used for manufacturing is small and there is no generation of by-products that cause a problem of disposal.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Tanaka 4-66-1, Horikiri, Katsushika-ku, Tokyo Miyoshi Oil & Fat Co., Ltd. (72) Inventor Akiaki Matsumoto 4-66-1, Horikiri, Katsushika-ku, Tokyo Miyoshi Oils and Fats Co., Ltd. (72) Inventor Masafumi Moriya 4-66-1 Horikiri, Katsushika-ku, Tokyo Miyoshi Oils and Fats Co., Ltd.

Claims (3)

[Claims] 1. An antibacterial agent having a silver coating formed on the surface of a carrier by baking a silver compound powder adhered to the surface of the carrier. 2. A method for producing an antibacterial agent, which comprises depositing a silver compound powder on the surface of a carrier and then baking the powder to form a silver film on the surface of the carrier. 3. The method for producing an antibacterial agent according to claim 2, wherein the silver compound powder is silver oxide powder and / or silver carbonate powder.