JPH0899812A - Metallic antibacterial agent and antibacterial material - Google Patents

Abstract

PURPOSE: To provide an inexpensive metallic antibacterial agent having high safety and high and long-acting bactericidal effect. CONSTITUTION: This powdery metallic antibacterial agent is composed of ceramic particles or base metal particles having an average particle diameter of 0.01-0.5μm and antibacterial metal particles having an average particle diameter of 0.0001-0.1μm and attached to the surface of the ceramic particles, etc., in dispersed state in an amount corresponding to 0.1-60wt.% based on the weight of the ceramic particles or the base metal particles. This antibacterial material contains the metallic antibacterial agent embedded in a matrix in a partly exposed state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial agent in the form of fine powder which utilizes the antibacterial property of the surface of an antibacterial metal, and an antibacterial material which holds the antibacterial agent on the surface.

[0002]

2. Description of the Related Art In recent years, nosocomial infection due to MRSA (methicillin-resistant Staphylococcus aureus), which is resistant to most antibiotics, has become a problem in many hospitals. The drug is once again in the spotlight. In other words, mercury, silver, copper,
It is known that metals such as zinc and their ions have bactericidal action, and the mechanism of bactericidal action of these antibacterial metals is different from that of antibiotics. This is because it is expected that even a fungus having a resistance does not show resistance to the bactericidal action of the antibacterial metal. In fact, it has been confirmed that these antibacterial metals, especially silver, have bactericidal action against various fungi and non-acquisition of resistance (“April Bulletin” April 1993 issue).

[0003] Antibacterial metals such as metal powders (silver powders, etc.), metal zeolites (silver zeolite: some of the zeolite's metal ions replaced with silver ions), silver-plated nonwoven fabrics, silver complexes, etc. Its use in form or state is being considered, and some of them have already been commercialized. That is, the antibacterial metal or metal compound is used as a fiber (eg, a fiber as a constituent material of clothes for medical workers or clothes for patients), a plastic molded product (eg, an inner wall of a refrigerator, a washing tub of a washing machine, In various products such as ballpoint pen grip part, bicycle handle), water purifying material for water purifier, etc., by embedding a part of the surface in an exposed state, or by adding and mixing with sand in the sandbox, etc., It is designed to exert a bactericidal action.

An antibacterial agent of an antibacterial metal typified by silver generally utilizes an antibacterial agent utilizing the antibacterial property of eluted silver ions and an antibacterial action by active oxygen generated on the surface of the antibacterial metal in a metallic state. Examples of the former include silver zeolite and silver complex having silver ions incorporated therein, and examples of the latter include silver powder and silver-plated fibers. Among these, those that utilize the bactericidal action by elution of silver ions, such as silver zeolite and silver complex, have a high antibacterial effect in the short term, but after long-term use, that is, most of the silver ions are eluted. After that, there is a problem that the antibacterial effect is significantly reduced. On the other hand, the one using silver powder has a high durability of antibacterial effect, but has a drawback that the antibacterial effect per silver amount used is not so high.
Further, with silver-plated fibers, the plated silver easily separates from the fibers, so that a hospital garment or the like woven with the silver-plated fibers has a drawback that the antibacterial effect is significantly reduced after several washings. Therefore, a metallic antibacterial agent such as a silver powder, a silver zeolite, a silver complex, a silver-plated non-woven fabric, etc., which has been or has been considered to be used, is expensive or does not have a sufficiently high bactericidal effect, or There was a problem that the antibacterial effect was not persistent.

[0005]

As the development of antibacterial products spreads, the demand for antibacterial metallic materials (metallic antibacterial agents) with higher safety, higher bactericidal effect or antibacterial effect, and cheaper Is high.

The present invention provides a finely powdered antibacterial metal material (that is, a metallic antibacterial agent) which has high safety, can maintain a high bactericidal effect for a long period of time, and can be manufactured at a lower cost. The purpose is to do.

[0007]

According to the present invention, an average particle size of 0.
Antibacterial agent having an average particle size of 0.0001 to 0.1 μm on the surface of the ceramic particles or base metal particles of 01 to 0.5 μm and corresponding to the amount of 0.1 to 60% by weight based on the weight of the ceramic particles or base metal particles. It is a finely powdered metallic antibacterial agent obtained by dispersing and adhering conductive metal particles.

The present invention also resides in an antibacterial material obtained by embedding the above-mentioned finely powdered metallic antibacterial agent with a part of the surface thereof being exposed.

Preferred embodiments of the present invention are as follows. 1) The specific surface area of ceramic particles or base metal particles is 5
The above-mentioned metallic antibacterial agent which is -100 m ² / g. 2) The specific surface area of ceramic particles or base metal particles is 1
The above metallic antibacterial agent is 0 to 100 m ² / g. 3) The above-mentioned metallic antibacterial agent in which the antibacterial metal is silver. 4) The above metal antibacterial agent, wherein the average particle diameter of the ceramic particles or base metal particles is 0.01 to 0.1 μm. 5) The above metallic antibacterial agent in which the ratio of the amount of antibacterial metal particles to the amount of ceramic particles or base metal particles is in the range of 1 to 25% by weight. 6) The above metallic antibacterial agent in which the average particle size of the antibacterial metal particles is in the range of 1 to 20% of the average particle size of the ceramic particles or the base metal particles.

According to the research conducted by the present inventor, ceramic fine particles (or base metal fine particles), particularly barium titanate,
Ceramic fine particles such as titanium dioxide and silica are available as stable fine particles with little cohesiveness, and when fine particles of antibacterial metal such as silver are dispersed and adhered to the surface of the particles, the silver fine particles are dispersed and adhered. The ceramic fine particles are not agglomerated so much and are uniformly dispersed in various molding materials such as resin materials. The silver fine particles dispersed and adhered to the ceramic fine particles are usually used alone. It has been found that the particle size is significantly smaller than that of the existing silver particles, and thus the silver fine particles have a very high specific surface area. Based on these findings, the inventors of the present invention have conducted research on the ceramic fine particles (or base metal) in which antibacterial metal fine particles such as fine silver particle-dispersed ceramic fine particles are dispersed and adhered to a molded body of various materials such as a resin material. We found a new fact that by kneading fine particles) so that a part of the particles is exposed on the surface of the molded product, the molded product can be given a highly effective and long-lasting antibacterial effect. It was

That is, even if the silver particles are fine, the average particle size is usually about several microns (for example, 1
It is commercialized as particles of 10 to 10 μm), and if the particles are smaller than that, they tend to form secondary aggregates and tertiary aggregates immediately because of their strong cohesive force. Is strong, it is difficult to restore primary particles by a simple dispersion operation. On the other hand, the fine silver particles supported on the ceramic fine particles or base metal fine particles as described above have a weak cohesive property when they are carried on the carrier even if the particle size is 0.1 μm or less, Therefore, there is a feature that it is easily dispersed uniformly in the resin material.

Further, the finely powdered metallic antibacterial agent of the present invention, when kneaded into a resin material, has a high compatibility with the resin material and little secondary aggregation, so that it is extremely effective in the resin material. There is an advantage that highly uniform dispersion is possible, and further, undesired fluctuations of resin characteristics such as deterioration of resin and fluctuations of fluidity are less likely to occur. Furthermore, since the metallic antibacterial agent of the present invention has a very high heat resistance such as 350 ° C. or higher (when silver is dispersed and adhered to the surface of titanium dioxide particles), it is kneaded with a thermoplastic resin under heating. When it is put in, the antibacterial property does not decrease, which is very advantageous. And a resin molded product (eg, film, three-dimensional molded product, filament) in which the metallic antibacterial agent of the present invention is kneaded
Has an advantage that it has a high degree of freedom in its use because it hardly changes the light resistance, weather resistance, chemical resistance, surface gloss, and physical durability of the resin material.

Examples of the ceramic fine particles or base metal fine particles that are the material (core) of the fine powdery metallic antibacterial agent of the present invention include barium titanate, titanium dioxide, silica (silicon dioxide) and alumina. Examples thereof include fine particles of (aluminum oxide) and fine particles of zirconium oxide, nickel, and copper (when silver is used as the antibacterial metal for coating). Particularly preferred among these are fine particles of ceramics such as barium titanate, titanium dioxide and silica. The ceramic fine particles or the base metal fine particles serving as the cores of these have an average particle diameter of 0.01
To 0.5 μm (preferably 0.1 μm or less, particularly preferably 0.08 μm or less). The specific surface area of the ceramic fine particles or base metal fine particles is 5 to 10
In the range of 0 m ² / g, it is particularly preferably from 10 to 100 m ² / g.

As means for dispersing and adhering fine particles of antibacterial metal on the surface of the above ceramic fine particles or base metal fine particles, a known chemical plating method can be used. That is, the nuclear material fine particles are dispersed in an aqueous solvent, mixed with an aqueous solution of an antibacterial metal compound such as an aqueous silver salt solution, and then a reducing agent is added to the surface of the dispersed nuclear material fine particles. It is a method of depositing fine particles of antibacterial metal such as silver.

As the antibacterial metal, silver has a high antibacterial property,
Further, since it is highly safe, it is easy to use, but it is also possible to use an antibacterial metal such as copper or zinc depending on the application.

The ratio of the ceramic part or base metal part which becomes a carrier (nucleus or core) when the antibacterial metal fine particles of the present invention are formed and the antibacterial metal part dispersed and adhered to the surface thereof is usually the former. Is 100 parts by weight,
The amount is 0.1 to 60 parts by weight (preferably 1 to 25 parts by weight). Alternatively, the ratio of the former to the latter is 70:20 to 99: 1.
(Weight ratio). In particular, the former: the latter is 66: 34-
Those of 95: 5 (weight ratio) are preferable.

The finely powdered metallic antibacterial agent of the present invention is used in various applications as a semi-permanent antibacterial agent by embedding it in a molded body of various materials with at least a part of its surface exposed. Can be used. For example, the antibacterial fiber can be obtained by mixing with a resin material such as polyester to form a fiber. This antibacterial fiber is woven or knitted with other fibers alone or with other fibers to form a cloth, which is then used for medical staff clothes, patient clothes,
It can be used as medical sheets, curtains in hospital rooms, bandages, etc., or as underwear and socks for ordinary people. Similarly, by mixing with resin material and then molding it into various shapes, the inner wall of the refrigerator, the internal parts of the refrigerator, the washing tank of the washing machine, the filter of the vacuum cleaner, the grip of the ballpoint pen, the interior parts of the automobile, the transmission of the telephone. Use as a handset, tableware, antibacterial paint, personal computer keyboard, wallpaper, water purification material for water purifier, plastic cutting board, caulking material, fishing net, film for packaging food such as meat, fish, vegetables and fruits, vase, etc. You can Alternatively, it can be used to sterilize the sandbox by mixing it with the sand in the sandbox. Further, by adding the finely powdered metallic antibacterial agent of the present invention to the water in the vase, it is possible to extend the life of the fresh flower that has been able to go to the vase. Furthermore, it is also possible to mix the deodorant powder and baby powder with the finely powdered metallic antibacterial agent of the present invention to suppress the growth of various bacteria on the skin surface on which the powder is sprayed.

[0018]

【Example】

[Example 1] Preparation of silver-titanium dioxide fine powder 1) Preparation of diamine silver nitrate solution 200 g of silver nitrate 8.0 g (including 5.0 g as Ag)
It was dissolved in L of pure water. To this, 50 mL of aqueous ammonia was added to obtain a solution of silver nitrate ammine complex (silver diamine nitrate). 2) Manufacture of fine titanium dioxide powder adhering to silver (10% by weight) To 45 g of titanium dioxide powder (average particle size: 0.02 μm, specific surface area: 40.8 m ² / g), obtain 1000 mL of pure water, and 1) above. The diamine silver nitrate solution was added and dispersed by ultrasonic waves. 200 mL of an aqueous glucose solution containing 10 g of glucose was added to this dispersion, and the mixture was stirred at 40 to 60 ° C. for 1 hour to deposit metallic silver on the surface of the titanium dioxide powder. The obtained silver-adhered powder is separated by decantation, washed and dried, and 50 g of silver (10% by weight) -adhered titanium dioxide fine powder (average particle diameter: 0.02 μm, specific surface area: 40.6 m ² / g) Got

[Example 2] Production of fine titanium dioxide powder adhering to silver 1) Preparation of diamine silver nitrate solution 1000 mL of 40 g of silver nitrate (including 25 g as Ag)
In pure water. To this, 250 mL of aqueous ammonia was added to obtain a solution of silver nitrate ammine complex (silver diamine nitrate). 2) Manufacture of fine titanium dioxide powder adhering to silver (50% by weight) 25 g of titanium dioxide powder (average particle size: 0.02 μm, specific surface area: 40.8 m ² / g) was added to the diamine silver nitrate solution obtained in 1) above. In addition, it was dispersed by ultrasonic waves. 500 mL of an aqueous glucose solution containing 50 g of glucose in this dispersion.
Was added and stirred at 40 to 60 ° C. for 1 hour to deposit metallic silver on the surface of the titanium dioxide powder. The silver-adhered powder obtained is separated by decantation, washed and dried.
0 g of silver (50% by weight) -adhered titanium dioxide fine powder (average particle diameter: 0.04 μm, specific surface area: 24.6 m ² / g) was obtained.

[Example 3] Preparation of silver-titanium dioxide fine powder 1) Preparation of diamine silver nitrate solution 90 mL of silver nitrate 4.0 g (containing 2.5 g as Ag)
In pure water. To this, 10 mL of aqueous ammonia was added to obtain a solution of silver nitrate ammine complex (silver diamine silver nitrate). 2) Manufacture of fine titanium dioxide powder adhering to silver (5% by weight) 47.5 g of titanium dioxide powder (average particle size: 0.2 μm, specific surface area: 11.43 m ^{2 /} g) and 250 mL of pure water,
And the silver diamine nitrate solution obtained in 1) above was added and dispersed by ultrasonic waves. 50 mL of an aqueous glucose solution containing 5 g of glucose was added to this dispersion and stirred at 40 to 60 ° C. for 1 hour to deposit metallic silver on the surface of the titanium dioxide powder. The obtained silver-adhered powder is separated by decantation, washed and dried to obtain 50 g of silver (5% by weight) -adhered titanium dioxide fine powder (average particle diameter: 0.2 μm, specific surface area: 1
0.06 m ² / g) was obtained. An electron micrograph (magnification: 60,000 times) of the above-mentioned silver-adhered titanium dioxide fine powder is shown in FIG. The state in which fine silver particles are dispersed and adhered to the surface of the titanium dioxide fine powder can be clearly seen.

[Example 4] Production of silver dioxide fine titanium dioxide powder 1) Preparation of silver nitrate diamine solution 8.0 g of silver nitrate (containing 5 g as Ag) was dissolved in 80 mL of pure water. 20 mL of ammonia water was added to this to obtain an ammine complex (silver diamine silver nitrate) solution of silver nitrate. 2) Manufacture of fine titanium dioxide powder adhering to silver (10% by weight) 45 g of titanium dioxide powder (average particle size: 0.2 μm, specific surface area: 11.43 m ² / g) was added to the diamine silver nitrate solution obtained in 1) above. In addition, it was dispersed by ultrasonic waves. This dispersion contains 100 g of glucose aqueous solution containing 10 g of glucose.
L was added and the mixture was stirred at 40 to 60 ° C. for 1 hour to deposit metallic silver on the surface of the titanium dioxide powder. The obtained silver-adhered powder is separated by decantation, washed and dried to give 50 g of silver (10 wt%)-adhered titanium dioxide fine powder (average particle size: 0.2 μm, specific surface area: 9.85 m ² / g). Got

[Example 5] Production of fine powder of titanium dioxide deposited on silver 1) Preparation of diamine silver nitrate solution 48 mL of 0.8 g of silver nitrate (containing 0.5 g as Ag)
In pure water. Add 2 mL of ammonia water to this,
An ammine complex (silver diamine nitrate) solution of silver nitrate was obtained. 2) Production of titanium dioxide fine powder adhering to silver (1% by weight) Titanium dioxide powder (average particle size: 0.2 μm, specific surface area: 11.43 m ^{2 /} g) 49.5 g of diamine diamine silver nitrate obtained in 1) above It was added to the solution and dispersed ultrasonically. This dispersion contains 10 g of an aqueous glucose solution containing 1 g of glucose.
L was added and the mixture was stirred at 40 to 60 ° C. for 1 hour to deposit metallic silver on the surface of the titanium dioxide powder. The obtained silver-adhered powder was separated by decantation, washed, and dried to obtain 50 g of silver (1% by weight) -adhered titanium dioxide fine powder (average particle size: 0.2 μm, specific surface area: 10.42 m ² /
g) was obtained.

Example 6 Evaluation as Antibacterial Agent As a control, silver powder (average particle diameter: 1 μm, specific surface area: 0.4 m ² / g) was used, and the silver-adhered titanium dioxide fine particles obtained in Examples 1 and 2 were used. The antibacterial properties of each of the powders were examined by a known method using Escherichia coli as a target and using a medium. As a result, it was observed that the silver-adhered titanium dioxide fine powder obtained in Example 2 exhibited a clearly high antibacterial property against pure silver powder. In addition, it was confirmed that the silver-adhered titanium dioxide fine powder of Example 1 exhibited a higher antibacterial property.

[Example 7] Evaluation as an antibacterial agent MRSA (resistant Staphylococcus aureus), Escherichia coli, and E. coli were prepared for each of the silver-adhered titanium dioxide fine powders prepared in Examples 3 and 5 having a silver-adhesion amount of 5% and 1%, respectively. And the antibacterial action against Pseudomonas aeruginosa, 50 mM phosphate buffer dispersion liquid (100 μg / mL
˜0.20 μg / mL) and a broth for sensitivity measurement (manufactured by Nissui Co., Ltd.) as a medium at 35 ° C.
The number of each bacterium that grew or decreased after culturing for a period of time was measured. The measurement results are shown in Table 1. In addition, a phosphate buffer containing no silver-titanium dioxide fine powder was used as a control, and the bacterial growth amount (the number of inoculated bacteria: 10
000, the number of bacteria after culturing: 100,000), the effective concentration of the antibacterial agent was determined when the number of bacteria after culturing was 50 or less with the same number of inoculated bacteria.

[0025]

[Table 1] Table 1 (effective concentration of antibacterial agent: unit: μg / mL) ────────────────────────────────── ───Silver-attached titanium dioxide fine powder MRSA E. coli Pseudomonas aeruginosa ───────────────────────────────────── Example 3 (Ag: 5%) 0.78 0.20 3.13 Example 5 (Ag: 1%) 1.56 0.20 6.25 ─────────────── ──────────────────────

Example 8 Production of Antibacterial Material The silver-adhered titanium dioxide fine powder of Example 1 was added to 1% by weight of ABS resin, mixed and molded by a known method to obtain an ABS resin sheet. It was When the surface of the obtained ABS resin sheet was examined by an electron microscope, many exposed surfaces of silver-deposited titanium dioxide fine powder were observed.

[Example 9] Production of antibacterial material (silver-adhered titanium dioxide fine powder kneaded resin film) and evaluation of antibacterial property The silver-adhered titanium dioxide fine powder of Example 3 was added to the polyethylene resin in an amount of 1% by weight. After mixing, the mixture was molded by a known method to obtain a 20 μm thick silver-adhered titanium dioxide fine powder kneaded resin film. When the surface of the resin film obtained by kneading the obtained silver-adhered titanium dioxide fine powder was examined by an electron microscope, many exposed surfaces of silver-adhered titanium dioxide fine powder were observed. Wrap the fillet of goldfish in the silver-adhered titanium dioxide fine powder kneaded resin film obtained above,
It was left at room temperature. At the same time, as a control, a resin film in which the silver-titanium dioxide fine powder was not kneaded was prepared. Similarly, a fillet of goldfish was wrapped and left at room temperature. When the discolored state of the fillet of Kinme sea bream was observed on both sides, after 16 days, the control of the Kinme sea bream fillet showed a clear discoloration (changed to dark color) after 16 days, but the silver-adhered titanium dioxide fine powder kneaded resin film No discoloration was seen in the fillet of Kimame sea bream wrapped in.

[Example 10] Production of antibacterial material (silver-adhered titanium dioxide fine powder kneaded resin filament) and evaluation of antibacterial property [0028] 1% by weight of the silver-adhered titanium dioxide fine powder of Example 3 was added to the polyethylene resin. After mixing, the mixture was molded by a known method to obtain a resin filament having a thickness of 300 μm and a fine powder of silver-attached titanium dioxide kneaded therein. When the surface of the resin filament kneaded with the fine silver-titanium dioxide fine powder thus obtained was examined with an electron microscope, an innumerable exposed surface of the fine silver-titanium dioxide fine powder was observed. Resin filament 30 cm (0.0
2 g) and 300 mL of water was placed in a vase, tulips were placed in the vase, and the mixture was left at room temperature. At the same time, as a control, only the same amount of water was put in a vase, tulips were placed in the vase, and the mixture was left at room temperature. When the condition of the flowers was observed after 10 days, wilting and discoloration (darkening) of the flowers were confirmed in the control, but almost no flowers were immersed in water containing the resin filaments kneaded with the silver-adhered titanium dioxide fine powder. No change was seen.

[0029]

The finely powdered metallic antibacterial agent of the present invention has a form in which fine particles of antibacterial metal are dispersed and adhered to the surface of ceramic fine particles or base metal fine particles, and the fine particles of antibacterial metal are Since it has a high specific surface area, if silver is taken as an example of the antibacterial metal, compared to pure silver particles,
It is inexpensive and can ensure high antibacterial properties. Furthermore, since the adhered surface is not an ion but a metal such as silver itself, its safety is high and its antibacterial activity is highly durable. Therefore, the finely powdered metallic antibacterial agent of the present invention is particularly useful as an antibacterial agent to be mixed into various medical materials, molded products, cosmetics, food packaging films and the like.

[Brief description of drawings]

1 is an electron micrograph (magnification: 60,000 times) of a silver-adhered titanium dioxide fine powder according to the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location D01F 1/10 6/46 A

Claims (8)

[Claims] 1. An average particle corresponding to an amount of 0.1 to 60% by weight based on the weight of the ceramic particle or base metal particle on the surface of the ceramic particle or base metal particle having an average particle diameter of 0.01 to 0.5 μm. Diameter 0.0001-0.1 μm
A fine powder metal antibacterial agent obtained by dispersing and adhering antibacterial metal particles. 2. The metallic antibacterial agent according to claim 1, wherein the specific surface area of the ceramic particles or base metal particles is 5 to 100 m ² / g. 3. The metallic antibacterial agent according to claim 1, wherein the ceramic particles or the base metal particles have a specific surface area of 10 to 100 m ² / g. 4. The metallic antibacterial agent according to claim 1, wherein the antibacterial metal is silver. 5. The metallic antibacterial agent according to claim 1, wherein the average particle diameter of the ceramic particles or base metal particles is 0.01 to 0.1 μm. 6. The metallic antibacterial agent according to claim 1, wherein the ratio of the amount of antibacterial metal particles to the amount of ceramic particles or base metal particles is in the range of 1 to 25% by weight. 7. The metallic antibacterial agent according to claim 1, wherein the average particle diameter of the antibacterial metal particles is in the range of 1 to 20% of the average particle diameter of the ceramic particles or the base metal particles. 8. An antibacterial material obtained by embedding the metallic antibacterial agent according to any one of claims 1 to 7 in a resin product or a textile product with a part of its surface exposed.