JP2000319109A - Antimicrobial material and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject material producible by a relatively inexpensive process, not impairing antimicrobial properties for a long-term practical period by dispersedly embedding antimicrobial agent particles in the surface of a base material in a partially exposed state. SOLUTION: Antimicrobial agent particles having preferably 0.01-100 μm average particle diameter [e.g. antimicrobial metal (Ag, Cu, Zn, Ni, etc.), 2-(4- thiazolyl)-benzimidazole, etc.], are subjected to embedding treatment (blast treatment), for example, by high-speed collision to the surface of a base material (the external surface or the internal surface of structure of a base material with which a microorganism of the outside can be brought into contact or, in the case of the base material being a foamy or porous material, the surface of foam or cell). Preferably the interval of the particles is 0.5 to <=10 μm size of ordinary microorganism cell and the dispersion density is such a degree as not to substantially cause the colony of microorganism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial material having an antibacterial property provided on all or a part of the surface of a substrate (an outer surface or an inner surface of a structure that can be contacted by external microorganisms) and a method for producing the same. .

[0002]

2. Description of the Related Art Recently, microbiological hygiene such as tableware, cooking utensils, medical utensils, etc. is not limited to those of which importance is placed on them, but also automobile supplies, housing / construction supplies, automobile supplies, daily miscellaneous goods, office equipment. In a wide range of products, such as those provided with antibacterial properties, attention has been paid.

[0003] Conventional techniques for imparting antibacterial properties to these products (substrates) include a technique (A) for forming a coating layer containing an antibacterial agent on the surface of the substrate and an antibacterial property for the substrate itself. And a technique (B) of concentrating or precipitating the composition in the surface layer of the base material.

As the prior art (A), for example, Japanese Patent Application Laid-Open No. Hei 10-251557 discloses an antibacterial property by applying a paint containing a specific antibacterial agent containing an antibacterial metal or an organic antibacterial substance. A coated steel sheet is disclosed. Japanese Patent Application Laid-Open No. 10-264297 discloses a laminate in which a resin film containing a specific antibacterial agent composition is adhered to the surface of a predetermined substrate via an adhesive layer.

[0005] The prior art (B) is a method which is often used for a metal base material.
No. 1785 discloses a stainless steel containing 0.1 to 10% by weight of Cu, which is annealed and then subjected to a desilica treatment on its surface to increase the concentration of Cu, thereby imparting antibacterial properties. Have been. Japanese Patent Application Laid-Open No. 10-306352 discloses a ferritic stainless steel sheet containing 1.0 to 5.0% by weight of Cu, in which Cu is precipitated on the surface to impart antibacterial properties. ing.

[0006]

However, in the prior art of the above-mentioned group (A), it is essentially unavoidable that a clear interface remains between the substrate and the coating layer. Even if the strength is enhanced, interfacial delamination occurs due to environmental external forces (temperature change, humidity change, frictional force, mechanical shock, etc.) acting on the surface of the substrate during its long-term practical use. There was a problem that the antibacterial property of the was impaired.

In the prior art of the above-mentioned group (B), the workability of the base material is deteriorated (for example, quenching becomes impossible) and the physical properties are deteriorated by forcibly including the antibacterial composition in the metal base material. There has been a problem that the production process is complicated and the cost is high due to the fear that the antibacterial component is increased in concentration or the like, because there is a concern that the antimicrobial composition may be reduced.

Accordingly, the present invention provides an antibacterial material which can be produced by a relatively simple and inexpensive process and which does not impair the antibacterial property of the substrate during a long practical use of the substrate, and a method for producing the same. Is an issue to be solved.

[0009]

Means for Solving the Problems (Structure of the First Invention) The structure of the first invention of the present application (the invention of claim 1) for solving the above-mentioned problems is that at least a part of the surface of the base material has an antibacterial property. An antimicrobial material in which material particles are partially exposed and dispersed and embedded.

(Structure of the Second Invention) The structure of the second invention (the invention described in claim 2) for solving the above-mentioned problem is as follows.
An antimicrobial material layer in which at least a part of the substrate surface has an antimicrobial material particle partially exposed and dispersed and embedded therein is formed in a state without a peelable interface between the substrate and the antimicrobial material layer. Yes,
It is an antibacterial material.

(Structure of Third Invention) The structure of the third invention of the present application (the invention according to claim 3) for solving the above problems is as follows.
An antibacterial material, wherein the antibacterial material particles according to the first or second invention are dispersed at a microbiologically effective density.

(Structure of the Fourth Invention) The structure of the fourth invention of the present application (the invention according to claim 4) for solving the above problems is as follows.
By burying the antimicrobial material particles in a partially exposed state by mechanical energy on at least a part of the substrate surface,
A method for producing an antibacterial material for producing the antibacterial material according to any of the first to third inventions.

(Structure of the Fifth Invention) The structure of the fifth invention (the invention described in claim 5) for solving the above problems is as follows.
The means for applying mechanical energy in the fourth invention is:
This is a method for producing an antibacterial material, which is a process of causing antibacterial material particles to collide with a base material at a high speed or a ball mill process.

[0014]

[Action and Effect of the Invention] (Action and Effect of the First Invention) In the first invention, since the antibacterial material particles are partially exposed and dispersed and embedded in at least a part of the surface of the base material,
Antibacterial properties are imparted to the surface portion of the substrate. When the antibacterial material particles are embedded in the entire surface of the substrate as described above, it goes without saying that the entire surface of the substrate is provided with antibacterial properties.

Further, the antibacterial material particles embedded in the base material can be easily subjected to environmental external forces such as temperature change, humidity change, frictional force, mechanical shock, etc. acting during a long period of practical use of the base material. Since it does not fall off, the antibacterial property of the substrate is ensured in a durable manner.

Further, since the antimicrobial particles are distributed only on the surface of the substrate, there is a possibility that the physical properties of the substrate may be deteriorated as in the prior art (B) as long as the substrate has a certain thickness. Absent.

(Function / Effect of Second Invention) In the second invention, the antibacterial material layer in which the antibacterial material particles are embedded is formed without a peelable interface between the antibacterial material layer and the substrate. ,
In addition to the actions and effects of the first invention, the phenomenon of interface delamination from the substrate cannot occur even in the entire surface layer portion including the antibacterial material, and thus the antibacterial properties of the substrate can be ensured in a durable manner.

(Action / Effect of Third Invention) In the third invention, the antibacterial material particles are dispersed at a microbiologically effective density (at least a density that does not cause microbial colonies). Even with a surface structure in which particles are dispersed, substantially complete antibacterial properties can be ensured.

(Function / Effect of the Fourth Invention) In the fourth invention, the antibacterial material particles are partially exposed and buried in the base material by mechanical energy. (B) without concern of interface delamination of the layer
Cost increase, deterioration of substrate workability,
The antibacterial material according to the first to third inventions can be easily and inexpensively manufactured without deteriorating the physical properties of the base material.

(Function / Effect of the Fifth Invention) When the means for imparting mechanical energy is a treatment in which antibacterial material particles collide with a base material at a high speed or a ball mill treatment, the function / effect of the fourth invention is particularly effective. It is remarkable, and it is easy to disperse the antibacterial material particles at a microbiologically effective density.

[0021]

Next, embodiments of the first to fifth inventions will be described. Hereinafter, the "present invention" indicates the first to fifth inventions collectively.

[Substrate] The material of the substrate is not limited as long as it is a solid material into which the antibacterial material particles can be embedded. Therefore, since heat resistance for processing is not required, for example, not only metal materials such as iron, aluminum, and general stainless steel, but also inorganic materials such as cement, concrete, mortar, glass, brick, and inorganic porous material. Thermoplastics such as polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, ABS resin, polystyrene, thermoplastic polyester resin, polyvinyl alcohol, polycarbonate, polyamide, phenol resin,
Thermosetting resin such as urea resin, epoxy resin, melamine resin, polyurethane resin, etc., in solid or foam form, various rubber materials in solid or foam form, cellulosic such as wood and paper Materials and the like can be used without limitation.

As the product form of the base material, a special shape or property (for example, that it is highly flat, that it is smooth or conversely rough, that it is not porous, etc.) Since it is not required, for example, metal medical tools such as forceps and scissors, metal tableware such as spoons and knives, aluminum wheels, automobile supplies such as metal bumpers and resin bumpers, dashboards, window glasses, aluminum sashes, etc. Household goods such as toilet bowls, wallpapers, mortar slate, ALC boards, flexible boards, building materials such as soundproof walls, casings and keyboards for various electrical products such as personal computers, hanging rings for trains, plastic molded products such as plastic films for various uses, and others Can be used as the substrate of the present invention without limitation.

[Exposed Surface of Substrate] The substrate is subjected to the antibacterial property imparting treatment of the present invention in which the antibacterial material particles are partially exposed and dispersed and embedded in part or all of the surface. .
As used herein, the term "substrate surface" refers to the outer surface of the substrate or the inner surface of the structure to which microorganisms in the environment can come in contact, or the surface of the bubbles or pores when the substrate is foamed or porous. To tell.

The inner surface of the structure of the base material can be subjected to an antibacterial treatment before assembling the structure. Antibacterial property imparting treatment can be performed to a certain depth by blasting.

When a part of the surface of the base material is subjected to an antibacterial treatment, for example, only a knife or scissors blade as a base material may be subjected to an antibacterial treatment, or a surface of a flush part of a toilet bowl as a base material may be used. For example, a case where only the antibacterial property imparting treatment is performed is exemplified.

Alternatively, according to certain special requirements, antibacterial properties can be imparted only to a specific area so as to form, for example, a stripe pattern, a polka dot pattern, or any other random pattern on a specific portion or all of the substrate surface. Processing can also be performed.

[Antibacterial material particles] The material constituting the antibacterial material particles is not limited as long as it is a material having antibacterial properties and as long as the material does not clearly lose antibacterial properties due to the process of embedding in a base material. The type is not limited.

Therefore, various organic substances and inorganic substances known to have antibacterial properties can be arbitrarily used, and in some cases, so-called antibacterial proteins or the like can be used. In particular, antibacterial metals are preferably used. Can be.
These antibacterial substances may be mixed with other components or impurities as long as the action is not significantly impaired.

The type of the above-mentioned antibacterial metal is not limited, but Ag, Cu, Zn, Ni or Co, and oxides (oxides, suboxides, peroxides, etc.) of these metals are particularly preferred. be able to. Also, next to these,
Cr and its oxides are also preferably exemplified.

Incidentally, regarding the antibacterial action mechanism of these antibacterial metals and their oxides, by generating ions of these metals on the surface of the base material, (1) a trace amount of metal ions are taken into the cells, and The effect of causing respiratory inhibition by binding to the SH group of the enzyme system, (2) the catalytic action of metal ions,
It is possible to point out an oligodynamic effect in which oxygen in the air or dissolved oxygen in water changes to active oxygen only on the cell surface and damages the cell membrane of bacterial cells.

In the present invention, "antimicrobial" is a concept including antifungal properties. And, as a material of which antifungal property is noted together with antibacterial property, or mainly of which antifungal property is noted, diiodomethyl-p-tolylsulfone (trade name: Amical 48), 2,4,4′-trichloro-
2'-hydroxydiphenyl ether (generic name triclosan), N- (trichloromethylthio) -4-cyclohexyl-2-dicarboximide (generic name orthoside), zinc-2-pyridinethiol-1-oxide (generic name zinc pyrithione) , 2-n-octyl-4
-Isothiazolin-3-one (trade name SKANE M)
-8), 2- (4-thiazolyl) -benzimidazole (commonly called TBZ), 2,3,5,6-tetrachloro-4
-(Methylsulfonyl) -pyridine (trade name Dens
il S-100), 2,3,5,6-tetrachloroisophthalonitrile (commonly known as TPN), 10-10'-oxybisphenoxy-arsenic (generic name: binazine),
6-di (Np-chlorophenylbiguanide) hexanedigluconate (general name: chlorhexidine gluconate), 2-methylcarbonyl-aminobenzimidazole (commonly called BCM), N- (fluorodichloro-methylthio) phthalimide (trade name: Preventol) A3),
N-dimethyl-N'-phenyl- (N'-fluorodichloro-methylthio) sulfamide (trade name Priventol A4S), p-chloro-m-cresol (trade name)
Preventor CMK) and the like. These can be embedded in a substrate, for example, in a state of being coated on appropriate particles. Of the above, TBZ is particularly preferred.

Although the size of the antibacterial material particles is not limited, the dispersing efficiency of the antibacterial material particles and the ease and reliability of embedding processing into the substrate (particularly in the case of the method of the fourth or fifth invention) are considered. When considered, the average particle size is 0.01
It is preferably in the range of μm to 100 μm, particularly preferably in the range of 1 μm to 30 μm.

Further, the antibacterial material particles having such an average particle diameter
When embedding into a substrate by the method of the invention or the fifth invention, it becomes easy to disperse and embed at a microbiologically effective density. In the present invention, a certain beneficial antibacterial property is ensured as long as the antibacterial material particles are embedded in a dispersed state, but it is particularly preferable that the dispersion density is a microbiologically effective density.

As used herein, "dispersion at a microbiologically effective density" refers to a state in which antimicrobial material particles are embedded at a dispersion density that does not substantially cause microbial colonies. Means that the particles are dispersed at intervals of about 0.5 μm to 10 μm, which is the normal size of the microbial cells. If the dispersion density of the antibacterial material particles is too low, the antibacterial property may be insufficient to some extent. On the other hand, if the dispersion density of the antibacterial material particles is too high to constitute a peelable integrated layer, one of the antibacterial material particles Since there is a concern that the part may fall off, the above-mentioned “dispersion at a microbiologically effective density” is one criterion for determining the amount of embedded antimicrobial material particles.

The form of the antibacterial material particles is not particularly limited, and the shape may be any shape such as a sphere, a square mass, a whisker, a scale, and the like. Further, the antibacterial material particles may be composed of only the antibacterial material, or may be used as particles in which the antibacterial material is adhered or coated on another kind of core material for the purpose of imparting mass and hardness to the particles. It is possible.

As the antibacterial material particles, only one kind may be used in kind or form, or two or more kinds may be used in combination.

[Embedded state of antibacterial material particles] The embedded state of the antibacterial material particles in the base material is determined by the external environmental force (temperature change, humidity change, frictional force, A part or most of the individual antibacterial material particles are buried in the base material and the other parts are exposed to such an extent that the particles do not fall off due to mechanical shock or the like. Here, “exposed” means that, for example, the antibacterial material particles may be deeper than the surface of the base material as long as the antibacterial material particles are in a state capable of exerting an antibacterial action on microorganisms in the outside world.

Since the antibacterial material particles are embedded in the base material, a peelable interface as seen in the prior art (A) exists between the entire antibacterial material particles and the base material. Essentially nonexistent. In a more preferred case, the antimicrobial material particles embedded in the substrate are chemically or physically integrated with the substrate. If the antibacterial material particles are excessively embedded as described above, an integrated layer composed of only the antibacterial material particles is formed, and there is a case where waste occurs that the surface side portion of the integrated layer is peeled off. However, the antimicrobial material particles directly embedded in the base material do not peel or fall off.

[Manufacturing method of antibacterial material] The manufacturing method of the antibacterial material of the first to third inventions is not limited at all as long as it is practically possible. However, a particularly preferred method is the production method of the fourth invention.

In the manufacturing method of the fourth invention, "mechanical energy" is a concept including the potential energy and the kinetic energy of an object, and the concrete method of the fourth invention is various, As a method of applying mechanical energy, antibacterial material particles are scattered on the surface of the base material and struck with an appropriate jig and embedded therein, or the antibacterial material particles are applied to a highly rigid brush-like jig. And a method in which the surface of the substrate is covered with a film of an antibacterial material and the material is beaten with the brush-like jig.

As a method of applying mechanical energy to the substrate side, antibacterial material particles scattered on a rigid bearing surface are
Examples of the method include a method of strongly pressing the base material and a method of hitting the metal base material.

In the manufacturing method of the fourth invention, in order to satisfactorily embed the antibacterial material particles in the base material, it is more preferable that the antibacterial material particles have a hardness equal to or higher than that of the base material.
When the base material is relatively hard, the metal or thermoplastic base material can be softened to some extent by heating.

However, among the above-mentioned production methods of the fourth invention, a method of embedding or ball milling the antibacterial material particles by colliding with the base material at a high speed is particularly preferable, and the former method is particularly preferable.

Ball milling refers to the case where a substrate is relatively hard to be damaged or broken by a mechanical impact, such as a metal material, and has relatively small dimensions (for example, bolts and nuts). Is treated with a ball mill together with antibacterial particles to embed the antibacterial particles in a substrate.

The process of embedding the antimicrobial material particles by colliding with the base material at a high speed includes embedding a gas or liquid containing the antimicrobial material particles.
For example, a method of spraying or colliding the base material at a high speed as a compressed air or a jet liquid flow, a method of colliding antibacterial material particles with the base material at a high speed by centrifugal force of a rotating body, and the like can be considered.

A particularly preferred method is a blast treatment generally known as shot blasting, shot peening, or the like, in which particles collide with a substrate at a high speed. As the blasting apparatus, a commercially available general mechanism, for example, a compressed air type such as a direct pressure type or a siphon type, or a centrifugal type can be suitably used.

As an example, when a compressed air type blasting device equipped with an injection nozzle is used, antibacterial material particles supplied from a storage tank such as a hopper and compressed air separately adjusted to a high pressure are appropriately mixed. The antibacterial material particles can be embedded in the substrate by projecting it from the injection nozzle toward the substrate at high speed.

In the blast treatment, the average particle size of the antibacterial material particles is in the range of 0.01 μm to 100 μm, particularly 1 μm
It is preferably within the range of from 30 to 30 μm, especially within the range of from 5 μm to 30 μm for a good dispersion state and embedded state of the antibacterial material particles.

The projection speed of the antibacterial material particles is appropriately selected according to the particle size and mass of the antibacterial material particles, the type of the base material, and the like.
For those having an average particle size in the range of 0 μm, 20 to 2
About 40 m / sec is preferable for a good dispersion state and an embedded state of the antibacterial material particles. In relation to the type of the base material, when the antibacterial material particles having the above average particle diameter are projected onto a relatively hard base material such as a metal, 150 to 240 m / m
Seconds (projection pressure of 4 to 6 kgf / cm ² ), when the antibacterial material particles having the above average particle diameter are projected onto a relatively low-hardness base material such as a synthetic resin, 50 to 150 m / sec (projection pressure of 2 to
About 4 kgf / cm ² ) is preferable.

In carrying out the blasting treatment, two or more kinds of antibacterial material particles may be mixed in advance in a kind or shape and then projected at once, or these may be divided into a plurality of types and projected.

Further, in response to the case where the surface of the base material is worn or scraped off to some extent during practical use, the projection speed is adjusted to adjust the projection speed so that the surface of the base material is deeper than the surface of the same base material. A process of embedding the antibacterial material particles in the portion and a process of embedding the antibacterial material particles shallowly in the base material surface may be performed.

[0053]

EXAMPLES (Preparation of Antibacterial Substrate Piece and Comparative Substrate Piece ) A predetermined number of plate-shaped base pieces each made of aluminum steel and having a size of 10 mm × 50 mm × 4 mm were prepared. One side surface (test surface) of the specimen was Cu ₂ O and Cu respectively by a direct pressure type compressed air type shot blasting device.
Shot blasting is performed by projecting particles having an average particle size of O, Cu and Ag of 10 μm at a projection pressure of ^{2 to 4} kgf / cm ² and a projection speed of about 150 m / sec. And The shot blast treatment was not performed on the other three pieces of the base material, and they were used as comparative base material pieces.

The antibacterial substrate and the comparative substrate were ultrasonically cleaned with acetone for 5 minutes and air-dried for 30 minutes.
The test surface was subjected to a sterilization treatment by UV irradiation for 20 seconds, and the following antibacterial test was performed.

( Antibacterial test ) Escherichia coli
IFO 3301) in 35 mL of normal broth medium at 35 ° C.
After culturing for 8 hours, a 50 mM phosphate buffer (pH
The test bacteria A solution was prepared by diluting 20,000 times in 7). Next, 1 mL of the test bacterium A solution was added to SCD manufactured by Nippon Pharmaceutical Co., Ltd.
Dilute with 9 mL of LP medium, 0.5 mL of this is SCD
The test bacteria B solution was prepared by diluting and mixing with 4.5 mL of LP medium.

1 mL of the test B solution was placed in a petri dish and pour-plated. In addition, 1 mL of a solution obtained by diluting 0.5 mL of the test bacterium B solution with 4.5 mL of the SCDLP medium and mixing them.
L, 0.1 mL, and 0.01 mL were each placed in a Petri dish and pour-plated.

These pour plate cultures are performed by adding 20 mL of Pearl Core standard agar medium kept at 45 to 50 ° C. to a Petri dish containing the bacterial solution, mixing gently, and solidifying the agar. It was carried out by a method called overnight culture.

After overnight culture, the number of colonies in a petri dish in which 50 to 500 colonies appeared was measured, and the viable cell count S1 at the start (test bacteria A solution) was determined by the following equation (1).

S1 = (C × R) / V (1) In the above formula (1), C is the number of colonies, and V is the volume (mL) of the liquid put in the dish in the pour plate culture.
Number) and R are dilution ratios of the solution from the test bacteria A solution.

Each of the three antibacterial substrate pieces and the comparative substrate piece was placed in a Petri dish, and 1 mL of the test bacterium A solution was dropped and left at 25 ° C. for 24 hours. While being recovered from the substrate piece, the substrate piece was carefully washed with 9 mL of SCDLP medium, and the washing solution was also collected (recovery A solution).

Put 1 mL of the recovered A solution into a petri dish,
Pour plating was performed in the same manner as described above. Also, 0.2 ml of a solution obtained by diluting 1 mL of the recovered A solution with 9 mL of the SCDLP medium and mixing.
L and 0.01 mL were each placed in a Petri dish, and pour-plated by the same method as described above. After overnight culture, the number of colonies in a petri dish in which 50 to 500 colonies appeared was measured, and the viable cell count S2 of the recovered A solution was calculated by the same formula as the above formula (1).
I asked.

From the viable cell count S1 of the test bacterium A solution and the viable cell count S2 of the recovered bacterium A solution, the sterilization rate D (%) was obtained by the following equation (2).
I asked.

D = (S1−S2) × 100 / S1 (2) Then, three antibacterial base pieces each having embedded therein antibacterial particles of Cu ₂ O, CuO, Cu and Ag were used. Table 1 shows each value and average value of the sterilization rates for the three pieces of the base material for comparison. In Table 1, the antibacterial base material pieces are described as “shot blasted steel”, and the comparative base material pieces are described as “comparative steel”. In addition, in the comparative substrate piece, the number of viable cells actually increased (S1 <S2). Therefore, for convenience of description, the sterilization rate was expressed as 0%.

As can be seen from Table 1, the sterilization rate of each antibacterial base material piece exceeded 73%, and it was evaluated that the antibacterial base material exhibited extremely satisfactory antibacterial properties.

[0065]

[Table 1]

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masana Hirai 41-Cho, Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside Toyota Central R & D Laboratories Co., Ltd. 41, Yokomichi, Toyota Central Research Laboratory Co., Ltd. (72) Inventor Hiroshi Kawahara 41, Toyoda Central R & D Laboratories, Co., Ltd. F-term (reference) 4D075 BB04Z BB12Z CA45 DC30 DC38 EA02 4H011 AA02 BA04 BB18 BC18 DA02 DB02 DB07 DD07 DE10 DF03 DF04 DG15

Claims (5)

[Claims] 1. An antibacterial material, wherein antibacterial material particles are embedded in a partly exposed state and dispersed in at least a part of the surface of a base material. 2. An antimicrobial material layer in which antimicrobial material particles are partially exposed and dispersed and embedded in at least a part of the surface of a substrate, without having a peelable interface with the substrate. An antimicrobial material characterized by being formed in a state. 3. The antimicrobial material according to claim 1, wherein the antimicrobial material particles are dispersed at a microbiologically effective density. 4. The antibacterial material according to claim 1, wherein the antibacterial material particles are partially buried by mechanical energy in at least a part of the surface of the base material. A method for producing an antibacterial material, comprising: 5. The method for producing an antibacterial material according to claim 4, wherein the means for applying mechanical energy is a process of causing the antibacterial material particles to collide with a base material at a high speed or a ball mill process.