JP2000344613A - Antimicrobial substance and antimicrobial material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antimicrobial substance and an antimicrobial material effective in aspects of antimicrobial activity, material processability and cost. SOLUTION: The antimicrobial substance is obtained by including preferably 0.1-60 wt.% of indium or indium oxide in a metal substrate. The antimicrobial material is prepared by forming the indium, indium oxide or antimicrobial substance into a state of a layer on a substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial material and an antibacterial material, and more particularly to an antibacterial material provided with antibacterial properties by containing indium or indium oxide.
The present invention relates to an antibacterial material in which the antibacterial material is provided in a layer on any substrate.

[0002]

2. Description of the Related Art Antimicrobial materials can be broadly classified into three types: inorganic, organic and natural. Among them, Ag (metal) is predominantly used as an inorganic antibacterial material, and Ti oxide, Cu (metal), Zn (oxide) and the like are also used.

[0003] In particular, Ag is well known for its strong antibacterial properties, and is used as a simple substance, and is also used in the form of being applied to a non-antibacterial material or mixed. In addition, antibacterial stainless steel with antibacterial properties added by adding Cu to stainless steel (Nissin Steel)
Also, Ti oxide and the like which are antibacterial photocatalysts are well known. Zn oxide also has an antibacterial photocatalytic action.

On the other hand, tin (Sn), which is a kind of metal, is a general-purpose metal. For example, alloy additives include solder, gunmetal, bearing alloys, type alloys, bronze (castings, spring materials), and the like.
The plating material is tin (Sn plated steel plate / beverage can,
It is used in various product fields such as cups, cookware, food processing equipment, etc., and corrosion-resistant and decorative accessories (spoons, forks, etc.). In addition, as a general theory, tin is often included in the category of antibacterial metals, so currently expensive A
If a tin alloy or the like can be provided as an antibacterial low-cost material for antibacterial product applications where g is used, its industrial significance is extremely large.

[0005]

However, the inventors of the present application have conducted an antibacterial test to confirm that tin and its oxides themselves do not exhibit antibacterial properties that can be said to be effective. Go and check. Accordingly, it is desired to impart effective antibacterial properties to tin or a material containing tin as a main component.

[0006] However, in exchange for imparting antibacterial properties, the excellent processability / moldability and durability of the appearance of the product, which are the characteristics of tin as a general-purpose metal (discoloration and surface deposits even after long-term use, may occur). It does not make sense to do that).

[0007] For example, Ag is formed on tin in the form of an alloy, plating or the like.
In the case where is applied, the product surface becomes dark due to oxidation, sulfide, etc. of Ag, which impairs the commercial value. Furthermore, when a metal oxide having a photocatalytic action is used, it is not possible to attach a light source to each tin product, which causes a problem that microorganisms propagate in the product when stored in a dark place.

In view of the above, the present inventor has already
In the specification attached to the application of Japanese Patent Application No. 9-240579, an antibacterial effect, a cost aspect, and a workability / formability of a material using a tin alloy containing a predetermined amount of zinc or zinc oxide or an oxidized product thereof are used. We propose an antimicrobial material that is advantageous in both aspects.

Meanwhile, according to the subsequent research conducted by the present inventors, indium or indium oxide, whose antibacterial properties had not been known until now, is alloyed with tin to form a work / indium.
It turned out to be an excellent antibacterial material with good moldability.

[0010] That is, indium or indium oxide sufficiently exhibits antibacterial activity to the extent required for the use of tin products, and the addition of indium or indium oxide lowers the melting point of tin and improves workability / moldability. The mechanical properties of the material are also improved. Also, the elution of indium ions as antibacterial components is promoted by the redox potential difference between tin and indium.

Further, indium or indium oxide may be
To exhibit good antibacterial properties even when contained in any material other than tin (for example, aluminum and other metal materials)
It has also been found that these indium- or indium-oxide-containing materials are suitable for performing processing such as coating on an arbitrary substrate.

Accordingly, the present invention provides a novel antibacterial material containing indium or indium oxide, which is advantageous in antibacterial power and material processing / formability, and an antibacterial material which is provided in a layer on any substrate. Is to be solved.

[0013]

(Structure of the first invention) The structure of the first invention (the invention described in claim 1) for solving the above-mentioned problem is that an antibacterial material containing indium or indium oxide is used. It is.

(Structure of the Second Invention) The structure of the second invention (the invention according to claim 2) for solving the above-mentioned problem is as follows.
An antibacterial material made of a tin alloy containing indium or indium oxide or an oxide thereof.

(Structure of Third Invention) The structure of the third invention (the invention described in claim 3) for solving the above-mentioned problem is as follows.
The antibacterial material according to the first or second invention, wherein the content of indium or indium oxide is 0.1 to 60% by weight.

(Structure of the Fourth Invention) The structure of the fourth invention (the invention described in claim 4) for solving the above problems is as follows.
The antibacterial material according to the first to third inventions, or the antibacterial material provided with indium or indium oxide so as to entirely or partially cover an arbitrary substrate.

[0017]

Action / Effects of the Invention (Action / Effects of the First Invention) The antibacterial mechanism of the antibacterial material containing indium or indium oxide is considered to be due to the following single actions (a) or (b). (A) A trace amount of indium ion binds to the SH group of the respiratory enzyme system of the microorganism to cause respiration inhibition. (B) By the catalytic action of indium ions, oxygen in the air or dissolved oxygen in the water is converted into active oxygen, which damages cell membranes.

The antibacterial mechanism described above is not limited to the case where the substrate of the antibacterial material is a metal (an alloy of any metal and indium or indium oxide), and the substrate of the antibacterial material is a nonmetallic inorganic material such as ceramic. In some cases, rubber,
It is also effective when it is an organic polymer material such as plastic.

(Action and Effect of Second Invention) The antibacterial material of the second invention, which is a tin-indium alloy, has a melting point similar to or lower than that of tin itself, and has excellent properties such as elongation of the material. / It has good moldability and can be easily finished into products of various shapes.

Further, by utilizing the low melting point, as in the fourth invention, it is easy to immerse a product made of another kind of material in a melt bath of the present material and perform a coating treatment. Further, the antimicrobial material of the second invention may be plated on the surface of a product made of another material, or may be coated in a gas phase.

Products finished in various forms as described above do not cause surface discoloration or powder precipitation for a long period of time, and have a material strength superior to that of a single tin material. , High commercial value.

(Action / Effect of Third Invention) In the first invention and the second invention, the content of indium or indium oxide in the antibacterial material is not limited as long as the antibacterial effect can be exhibited. .1 to 60% by weight
In particular, the antibacterial effect is exhibited particularly effectively and efficiently.

If the content is less than 0.1% by weight, the antibacterial action may be insufficient due to a shortage of the absolute amount of indium or indium oxide, and the content exceeds 60% by weight. However, the increase in the antibacterial activity due to the increase in indium has leveled off, and on the other hand, an excessively large indium composition ratio may affect the softening of the alloy material and the cost.

(Operation and Effect of the Fourth Invention) First to third inventions
The antibacterial material of the present invention can be used as various antibacterial products by molding them as they are. However, as in the fourth invention, any antibacterial material can be used on any substrate (the surface of various products made of any material). Antimicrobial properties may be imparted to these products by providing them so as to cover them completely or partially. Furthermore, indium or indium oxide can be provided as it is so as to cover the entire surface or any part of any substrate.

The antimicrobial material may be provided so as to cover the entire surface or the entire surface of the substrate by liquid phase coating,
Means such as vapor phase coating, plating, and supporting or embedding the particulate antibacterial material on the surface of the substrate can be adopted. If these means are used arbitrarily according to the type and shape of the substrate, etc. good.

According to the fourth aspect of the invention, it is possible to reduce the amount of the antibacterial material used, to impart antibacterial properties to various products after their production, and to make it difficult to contain indium or indium oxide. Antimicrobial properties can be easily imparted to products made of various materials.

[0027]

Next, embodiments of the first to fourth inventions will be described. In the following, when simply saying "the present invention", the first to fourth inventions are collectively referred to.

(Antimicrobial Material) The antimicrobial material of the present invention is a material in which indium or indium oxide is contained in a material which is a substrate (matrix).

The content of indium or indium oxide must be equal to or more than the necessary effective amount as an antibacterial component. However, the required effective amount as an antibacterial component differs between, for example, a medical device requiring a high level of antibacterial activity and a daily necessity such as stationery which requires a lower antibacterial activity. Therefore, the lower limit of the content cannot be uniformly limited. However, as one standard, for example, a numerical value of "0.1% by weight or more" with respect to the matrix of the antibacterial material can be cited.

On the other hand, it is difficult to uniformly limit the upper limit of the content of indium or indium oxide depending on the use of the antibacterial material, but one standard is a numerical value of "60% by weight or less". Can be mentioned. The reason is that even if the amount exceeds 60% by weight, the antibacterial activity reaches a peak, and on the other hand, there is a concern that softening of the antibacterial material and an increase in cost may be affected.

In consideration of a practical balance between the antibacterial activity, cost, and processability of the antibacterial material, the content of indium or indium oxide is particularly preferably 0.5 to 5% by weight.

Next, as the kind of indium to be contained, the latter is more preferable among indium and indium oxide, and among the indium oxides, monovalent indium oxide In ₂ O is particularly preferable.

(Substrate and Content of Antimicrobial Material) The substrate serving as the matrix of the antimicrobial material is typically a metal, especially tin, and in these cases, the content of indium or indium oxide is An alloy of a substrate metal and indium or indium oxide, or a so-called composition gradient alloy in which indium in the substrate metal is concentrated on the surface by preferential oxidation.

The material structure of the alloy is not limited, and may be, for example, a single-phase structure or a mixed structure as seen in a eutectic alloy. The alloy of the substrate metal and indium or indium oxide may not be oxidized, or may have at least the surface oxidized by means such as heating.

Taking the case where the substrate metal is tin as an example, as an example of the case where the alloy of tin and indium or indium oxide is oxidized, there is a case where these form a composite oxide. It is. Further, there may be a mixed system of tin metal / indium oxide and a mixed system of tin oxide / metal indium.

The antimicrobial material having the above-mentioned metal as a substrate is not limited to the above-mentioned various alloys or oxidized products thereof. In order to reinforce the action and effect of the above, furthermore, in order to express other preferable actions and effects while maintaining the antibacterial action, other optional alloy components, additives, etc. are added to the third component and the fourth component. Etc. may be included.

In addition to metals, non-metallic inorganic materials such as ceramics, rubbers,
An organic polymer material such as plastic can also be used. In these cases, indium or indium oxide can be contained, for example, in the form of fine particles dispersed therein, and further, an alloy of the substrate metal and indium or indium oxide or an oxidized product thereof or a composition containing these as a main component Can be contained in the form of fine particles dispersed in the non-metallic substrate.

Even when the substrate of the antibacterial material is a nonmetallic material, it can contain the third component, the fourth component and the like for any purpose as described above.

(Material form of antibacterial material) The specific form of the antibacterial material of the present invention may be any raw material such as bulk, plate, powder, etc. It may be molded / processed. Other forms such as foil (foil) and wire (wire) are of course included. The following antibacterial materials are also typical material forms.

(Antimicrobial Material) The antimicrobial material according to the fourth aspect of the present invention is provided by providing the above various antimicrobial materials, or indium or indium oxide as they are, so as to entirely or partially cover an arbitrary substrate. can do.

The antibacterial material may be provided so as to cover the whole or partial surface of the base material, for example, in a melt bath of the above antibacterial material or metal indium or indium oxide which is a fusible material such as metal. The base product is immersed in, or the base product is immersed in a melt bath of unvulcanized rubber or plastic in which the above antibacterial material fine particles, metal indium fine particles or indium oxide fine particles are dispersed, and subjected to liquid phase coating It is also easy (the rubber is then thermally vulcanized).

Further, the surface of the base material is plated with an antimicrobial material such as a metal, metal indium or indium oxide, and the unvulcanized rubber or plastic in which the antimicrobial material fine particles, the metal indium fine particles or the indium oxide fine particles are dispersed. The melt can be applied by various means.

Further, mechanical energy such as vapor phase coating by various means, treatment of supporting the particulate antibacterial material by immersing the porous substrate in the dispersion of antibacterial material fine particles, or blasting of the particulate antibacterial material is used. A method such as embedding in the surface of the base material by means of the above-described method can be adopted, and these means may be arbitrarily used according to the type and shape of the base material.

(Commodity form of antibacterial material) The antibacterial material and the antibacterial material according to the present invention include metal medical tools such as forceps and scissors, metal tableware such as spoons and knives, aluminum wheels, metal bumpers and the like. Automotive supplies such as resin bumpers and dashboards, window glass, aluminum sashes, toilets, wallpaper and other housing supplies, mortar slate, ALC boards, flexible boards, sound-insulating walls and other building materials, personal computers and other electrical products casings and keyboards, It can be used without limitation for plastic trains, plastic molded products such as plastic films for various uses, and other various products.

[0045]

Advantageous Embodiments of the Invention The following (1) to (20)
Next, useful embodiments of the first to fourth inventions of the present application will be listed.

(1) An antibacterial material containing indium or indium oxide. (2) The content of indium or indium oxide in the above (1) is 0.1 to 60% by weight. (3) The content of indium or indium oxide in the above (1) is 0.5 to 5% by weight. (4) When the antibacterial material contains indium oxide, the indium oxide is a monovalent indium oxide In.
₂ O. (5) In the above (1) to (4), the antibacterial material is an alloy of a substrate metal and indium or indium oxide or an oxide thereof. (6) In (5) above, the oxide of the alloy of the substrate metal and indium or indium oxide forms a composite oxide. (7) In the above (5), the antibacterial material is a mixed system of an oxide of a substrate metal and indium, or a mixed system of a substrate metal and indium oxide. (8) In the above (5) to (7), the alloy has a single phase structure or a mixed structure such as a eutectic alloy. (9) In the above (5) to (8), the alloy is a tin alloy or an oxide thereof. (10) In the above (1) to (4), the substrate of the antibacterial material is a nonmetallic inorganic material such as ceramic, or an organic polymer material such as rubber or plastic. (11) In the above (10), the substrate contains indium or indium oxide in the form of fine particles dispersed. (12) In the above (10), the substrate is the above (5) to
(9) An alloy of a substrate metal and indium or indium oxide or an oxide thereof is contained in the form of fine particles dispersed therein. (13) The antibacterial material of (1) to (12) contains another component for reinforcing the antibacterial action or for imparting another preferable action or effect without inhibiting the antibacterial action. . (14) The antibacterial material of (1) to (13) is bulk,
It is in the form of a raw material such as a plate or a powder, or is formed / processed into a specific product having an arbitrary three-dimensional shape, or is in the form of a foil, a wire or the like. (15) The antimicrobial material according to (1) to (12) is provided so as to entirely or partially cover an arbitrary substrate. (16) The antibacterial material is formed by providing indium or indium oxide so as to entirely or partially cover an arbitrary base material. (17) The antibacterial material, indium or indium oxide provided so as to entirely or partially cover the substrate in the above (15) to (16) is subjected to a liquid phase coating process, a gas phase coating process or a plating process. It is provided. (18) The antibacterial material, indium or indium oxide provided so as to entirely or partially cover the substrate in (15) to (16) above is obtained by immersing the porous substrate in the antibacterial material fine particle dispersion. It is provided by the carrying process. (19) The antibacterial material, indium or indium oxide provided so as to entirely or partially cover the base material in the above (15) to (16) provides mechanical energy such as blast treatment to the granular antibacterial material. It is provided by embedding by means to be used. (20) The product form of the antibacterial material or the antibacterial material of the above (1) to (19) is a metal medical tool, metal tableware, an automobile article, a house article, a building material, or a plastic molded article for various uses. It is.

[0047]

EXAMPLES Examples and comparative examples of the present invention will be described below.

[Preparation of antibacterial material and comparative material]
Using n and Sn raw materials, the weight ratio In / Sn of both was 0/100 as Comparative Example 1, 0.5 / 99.5 as Example 1, 1/99 as Example 2, and Example 3 respectively.
4/96, Example 4 15/85, Example 5
15 / g was weighed so as to be 60/40 as 100% and as Example 6 as 100/0. One to several samples were prepared for the weighed materials in each of these examples.

Each sample of the weighed material in each of the examples was placed in an alumina container, placed in an electric furnace maintained at 150 to 270 ° C., and heated to melt. Next, these hot melts are cast into a ceramic container having a smooth bottom surface and allowed to cool naturally,
A disk-shaped specimen having a diameter of about 30 mm and a thickness of 2 mm having a smooth surface formed by the smooth bottom surface of the container was obtained.

Further, the smooth surface of the disc-shaped test piece was put into a sputtering apparatus and sputter-cleaned in Ar gas under a predetermined condition to remove dirt on the surface to obtain a clean surface. For antibacterial test.

Note that "List of antibacterial test results" described later.
In the above, as a test piece different from the test piece, a plating bath of the alloy according to the present example (In / Sn weight ratio of 1
A test piece (Example 7) plated on a Fe base plate using a plating bath of 0/90, and a melt bath of the alloy according to the example (In / Sn weight ratio 15/85) However, a test piece (Example 8) coated on a glass plate by using a melt bath was also included.

In addition, for an arbitrary number of samples of one to several samples of the disc-shaped test pieces according to each example, the disc-shaped test pieces were maintained at 100 ° C. after the sputter cleaning. , And heated for 20 hours to perform an antibacterial test after performing a surface oxidation treatment on a smooth surface. The surface oxidation treatment of the sample group of Comparative Example 1 was performed by heating at 100 ° C. for 200 hours, heating at a maximum temperature of 180 ° C. in high-pressure steam for 10 hours, and nitric acid as a strong acid. Immersion is included.

Next, using an indium oxide (In ₂ O ₃ ) target, a sample (Example 9) in which indium oxide was coated on a Mg alloy substrate by sputtering was prepared. In addition, an uncoated one was designated as Comparative Example 2, and these plate-like test pieces were subjected to an antibacterial test. The results are shown in the list of antibacterial test results described below.

[Antibacterial test] Escherichia coli
IFO 3301) in normal broth medium (Eiken Chemical Co., Ltd.) for 35
After culturing at 18 ° C. for 18 hours, the culture was diluted with 50 mM phosphate buffer (pH 7) to prepare a test bacterial solution (about 2 × 10 ⁵ individuals / ml).

Next, the non-oxidized sample and the oxidized sample of the disc-shaped test specimen according to each of the above examples were placed horizontally in an environment where there was no contamination of various bacteria and no sunlight or artificial light was applied. Allow to stand, and add 0.5 ml of each of the test bacterial solutions described above to their smooth surfaces, and add 25 °
C for 24 hours.

Thereafter, a test bacterial solution was collected from each disk-shaped test sample, and the remaining test bacterial solution was also added to the SCDLP medium.
By washing out with 5 ml, the test bacterial solution on each disk-shaped test sample was almost completely recovered. Then, a part (1 ml of about 5 ml) of the recovered solution was subjected to a pour plate culture method (37 ° C.,
1 day), the viable cell count 24 hours later was measured.

The procedure of the above-mentioned pour plate culture method is as follows. A part (1 ml) of the above-mentioned recovered solution is put in a petri dish and kept at 45 ° C.
20 ml of Pearl Core standard agar medium (manufactured by Eiken Chemical Co., Ltd.) kept at 50 ° C. was added and mixed gently. After the agar medium had solidified, it was cultured at 37 ° C. for 1 day, and the number of colonies was measured. is there. In addition, the above-mentioned recovered liquid used for the culture was used after being diluted at a predetermined magnification, and the count of the number of colonies was correspondingly multiplied by the predetermined magnification to obtain a measurement result.

Based on the viable cell count thus measured, the presence or absence of antibacterial activity was determined for each sample according to each example. That is, when the number of viable bacteria after 24 hours is smaller than the number of viable bacteria at the start, it is determined that there is antibacterial activity (indicated by a circle in the antibacterial test result list), and conversely, Was determined to have no antibacterial activity (represented by x in the list of antibacterial activity test results).

[Evaluation of Antibacterial Material] The test results of each sample according to each of the examples and comparative examples are listed below for the non-oxidized and oxidized samples. In addition, in this list, the term shown with "-" indicates that the test was not performed.

Examples / Comparative Examples Non-Oxidation Treatment Oxidation Treatment Example 1 ○ ○ Example 2 ○ ○ Example 3 ○ ○ Example 4 ○ ○ Example 5 ○ ○ Example 6 ○-Example 7 ○ ○ Example 8 ○ ○ Example 9 ○-Comparative Example 1 × × Comparative Example 2 ×-As is clear from the above results, the material consisting of tin alone of Comparative Example 1 does not show antibacterial properties, while the indium of Example 6 And the tin-indium alloy materials of Examples 1 to 5 exhibited sufficient antibacterial properties without being significantly affected by the indium content. The Mg alloy material of Comparative Example 2 did not show antibacterial properties,
When the material is coated with indium oxide, antibacterial properties are exhibited.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takashi Shimamura 41-cho, Yokomichi, Nagakute-cho, Aichi-gun, Aichi F-1 term in Toyota Central R & D Laboratories Co., Ltd. 4H011 AA02 BB18 DA01 DC10

Claims (4)

[Claims] 1. An antibacterial material containing indium or indium oxide. 2. An antibacterial material comprising a tin alloy containing indium or indium oxide or an oxide thereof. 3. The antibacterial material according to claim 1, wherein the content of indium or indium oxide is 0.1 to 60% by weight. 4. The antibacterial material according to any one of claims 1 to 3, or indium or indium oxide,
An antibacterial material provided so as to entirely or partially cover an arbitrary substrate.