Fluid dispersion, manufacturing method of antibacterial substrate and manufacturing method of conjugate

Abstract

To provide a fluid dispersion including an antibacterial metal unlikely to cause sedimentation, capable of obtaining an antibacterial substrate having sufficient antibacterial properties by being applied to a substrate, and also to provide a manufacturing method of an antibacterial substrate using the fluid dispersion and a manufacturing method of a conjugate.SOLUTION: A fluid dispersion includes, in a medium, submicron-sized antibacterial metal particles and a silane coupling agent. A content of the antibacterial metal particles is 0.00005 to 0.05 mass% based on a total amount of the fluid dispersion. The silane coupling agent includes an organic functional group containing a sulfur atom or a nitrogen atom. A mass ratio of the silane coupling agent to the antibacterial metal particles is 0.007 to 2.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to dispersions, methods for making antimicrobial substrates, and methods for making conjugates. [Background technology]

[0002] A method of applying a composition such as a solution containing an antibacterial agent to a product made of glass, plastic, metal, etc., is known as a treatment method for imparting antibacterial properties to the product. For example, Patent Document 1 describes an example of an antibacterial treatment method. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 11-116414 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional dispersions containing antibacterial metals as antibacterial agents, increasing the content of the antibacterial metal to impart superior antibacterial properties makes the dispersion more susceptible to precipitation, whereas decreasing the content of the antibacterial metal to suppress precipitation in the dispersion makes it impossible to impart sufficient antibacterial properties.

[0005] The present disclosure aims to provide a dispersion containing an antibacterial metal that is unlikely to cause precipitation and that can provide an antibacterial substrate having sufficient antibacterial properties by applying it to a substrate. The present disclosure also aims to provide a method for producing an antibacterial substrate using the dispersion, and a method for producing a bonded body. [Means for solving the problem]

[0006] The present invention provides the following [1] to

[11] . [1] A dispersion liquid containing submicron-sized antibacterial metal particles and a silane coupling agent in a medium, The content of the antibacterial metal particles is 0.00005 to 0.05% by mass based on the total amount of the dispersion liquid, The silane coupling agent has an organic functional group containing a sulfur atom or a nitrogen atom, A mass ratio of the silane coupling agent to the antibacterial metal particles is 0.007 to 2. [2] The dispersion liquid according to [1], wherein the antibacterial metal particles are particles formed by the reduction of antibacterial metal ions in the medium by a reducing agent. [3] The dispersion according to [1] or [2], wherein the antibacterial metal particles are silver particles. [4] The dispersion liquid according to any one of [1] to [3], wherein the organic functional group containing a sulfur atom is an organic functional group having a mercapto group. [5] The dispersion according to any one of [1] to [4], wherein the content of the antibacterial metal particles is 0.0005 to 0.005% by mass based on the total amount of the dispersion. [6] The dispersion according to any one of [1] to [5], wherein the mass ratio of the silane coupling agent to the antibacterial metal particles is 0.05 to 0.5. [7] A method for producing an antibacterial substrate by contacting a substrate with an antibacterial dispersion, The antibacterial dispersion is a dispersion according to any one of [1] to [6]. [8] The method according to [7], comprising contacting the substrate with the antibacterial dispersion and removing at least a portion of the volatile matter in the antibacterial dispersion at 25 to 120°C. [9] The method according to [7] or [8], wherein the substrate is brought into contact with the antibacterial dispersion by immersing the substrate in the antibacterial dispersion.

[10] The method according to any one of [7] to [9], wherein the substrate is a resin substrate or a fibrous substrate.

[11] A method for producing a bonded body for bonding a first base material and a second base material facing each other, comprising the steps of: At least one of the first substrate and the second substrate has an opposing surface which is a hydrophilic resin substrate, A method for producing a bonded body, comprising forming a layer made of the dispersion liquid according to any one of [1] to [6] on at least one of the opposing surfaces, and then bonding the surfaces. Effect of the Invention

[0007] According to the present invention, it is possible to provide a dispersion liquid containing an antibacterial metal that is unlikely to cause precipitation and that can obtain an antibacterial substrate having sufficient antibacterial properties by applying it to a substrate. Furthermore, according to the present invention, it is possible to suppress the antibacterial metal particles contained in the dispersion from becoming finer over time. In addition, the dispersion liquid has little effect on the color of the substrate, the antibacterial substrate obtained using this dispersion liquid has sufficient durability, and the bonded body obtained using this dispersion liquid has sufficient antibacterial properties and adhesive strength. Furthermore, according to the present invention, it is possible to provide a method for producing an antibacterial substrate using this dispersion liquid, and a method for producing a bonded body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described, but the invention is not limited to this embodiment.

[0009] The dispersion according to the embodiment includes antimicrobial metal particles of submicron size.

[0010] The antibacterial metal particles are particles made of an antibacterial metal, and the antibacterial properties of the antibacterial metal can be determined based on, for example, JIS Z2801. Examples of the antibacterial metal include silver, copper, zinc, cobalt, nickel, aluminum, molybdenum, vanadium, zirconium, tungsten, palladium, and lead. The antibacterial metal particles are preferably silver particles (antibacterial silver particles). In this case, the antibacterial base material formed using the dispersion liquid has more sufficient antibacterial properties.

[0011] The particle size of the antibacterial metal particles is less than 1 μm, that is, submicron. The particle size of the antibacterial metal particles can be, for example, 750 nm or less, 500 nm or less, or 250 nm or less. The particle size of the antibacterial metal particles can be 1 nm or more, 10 nm or more, 50 nm or more, or 100 nm or more. The particle size of the antibacterial metal particles can also be 1 to 750 nm, 1 to 500 nm, 1 to 250 nm, 10 to 750 nm, 10 to 500 nm, 10 to 250 nm, 50 to 750 nm, 50 to 500 nm, 50 to 250 nm, 100 to 750 nm, 100 to 500 nm, or 100 to 250 nm. By having a particle size of 1 nm or more, the surface area of ​​the antibacterial metal particles is sufficiently large, and sufficient antibacterial properties can be exhibited even when bonded to a silane coupling agent having an organic functional group containing a sulfur atom or a nitrogen atom, which will be described later. When the particle size of the antibacterial metal particles is within the above range, the dispersion is less likely to cause precipitation, and when applied to a substrate, an antibacterial substrate having sufficient antibacterial properties can be obtained. Furthermore, the antibacterial metal particles contained therein can be prevented from becoming finer over time. In addition, the dispersion has little effect on the color of the substrate, the antibacterial substrate obtained using the dispersion has sufficient durability, and the bonded body obtained using the dispersion has sufficient antibacterial properties and adhesive strength.

[0012] The antibacterial metal particles may be produced by a method in which bulk raw materials are pulverized to the desired size by mechanical crushing or the like, or by a method in which cluster-shaped raw materials are constructed to the desired size.

[0013] Methods for producing antibacterial metal particles include a gas phase method and a liquid phase method. The gas phase method is a method in which a synthesis reaction is mainly carried out by a physical method, such as a sputtering method and a gas evaporation method. The liquid phase method is a method in which nanoparticles are mainly obtained by a chemical method, such as a method in which an antibacterial metal source is reduced in a solvent to precipitate nanoparticles. In this case, a surface protective agent (dispersant) may be used. The antibacterial metal source is typically an antibacterial metal ion present in a solvent (see, for example, Surface Technology, 2008, Vol. 59, No. 11, pp. 724-728).

[0014] The liquid phase method produces a solution in which metal nanoparticles are dispersed in a solvent. This solution is in the form of metal nanoparticles dispersed in a solvent, i.e., a metal colloid. It is preferable that the antibacterial metal particles are formed by the liquid phase method. In this case, since the antibacterial metal particles can be obtained as nanoparticles (antibacterial metal particles of submicron size), the dispersion is less likely to precipitate and can impart excellent antibacterial properties when applied to a substrate.

[0015] When metals become colloids with particle diameters of several to several hundred nm, plasmon resonance occurs, causing changes in magnetic and optical properties. For example, gold turns reddish purple, and silver turns yellow. Therefore, depending on the color of the solution, it can be determined that the solution is a colloidal solution, that is, that metal particles with particle diameters of several to several hundred nm (submicron-sized metal particles) are dispersed in the solution (see, for example, Journal of the Adhesion Society of Japan, 2008, Vol. 44, No. 11, pp. 433-437, and Surface Chemistry, 2008, Vol. 29, No. 6, pp. 350-355).

[0016] Whether antibacterial metal particles are submicron size can also be measured by photon correlation spectroscopy. That is, when the most frequent particle size (mode diameter) on a number basis is smaller than 1 μm in the particle size distribution measured by photon correlation spectroscopy, the antibacterial metal particles can be determined to be submicron size. Note that the resolution for measuring the mode diameter is preferably 10 nm or less.

[0017] The antibacterial metal particles may have various shapes, such as spheres, plates, needles, rods, polyhedrons, blocks, etc. The shapes of the antibacterial metal particles contained in the dispersion do not all need to be the same, and a mixture of a plurality of shapes may be used.

[0018] The antibacterial metal source may be, for example, an antibacterial metal ion. In the case of antibacterial silver particles, silver ions contained in an aqueous silver nitrate solution may be used as the antibacterial metal source.

[0019] The antibacterial metal source can be reduced by the action of a reducing agent, by irradiation with ultraviolet light, etc. Examples of the reducing agent include sodium borohydride, hydrazine, alcohol, ascorbic acid, and dimethylformamide.

[0020] The surface protective agent (dispersant) used in the liquid phase method is one that has the effect of suppressing the association (aggregation) of nanoparticles. For example, a silane coupling agent, citric acid, etc. can be used as the surface protective agent. This silane coupling agent may be a silane coupling agent having an organic functional group containing a sulfur atom or a nitrogen atom, or may be another silane coupling agent.

[0021] The content of the antibacterial metal particles is 0.00005 to 0.05% by mass based on the total amount of the dispersion. When the content of the antibacterial metal particles is within the above range, the dispersion is less likely to cause precipitation, and an antibacterial substrate having sufficient antibacterial properties can be obtained by applying the dispersion to a substrate. Furthermore, the antibacterial metal particles contained in the dispersion can be prevented from becoming finer over time. In addition, the dispersion has little effect on the color of the substrate, the antibacterial substrate obtained using this dispersion has sufficient durability, and the bonded body obtained using this dispersion has sufficient antibacterial properties and adhesive strength. The content of the antibacterial metal particles can also be 0.0005 to 0.005% by mass, 0.0006 to 0.004% by mass, or 0.0007 to 0.003% by mass based on the total amount of the dispersion.

[0022] The dispersion liquid according to the embodiment contains a silane coupling agent having an organic functional group containing a sulfur atom or a nitrogen atom.

[0023] The silane coupling agent can be represented, for example, by the following general formula (1). R n -SiX (4-n) …(1)

[0024] In the formula, R represents an organic group (at least one of the organic groups contains a sulfur atom or a nitrogen atom), X represents a hydroxyl group or a hydrolyzable group, and n represents a number of 1 to 3. At least one hydrogen atom of the organic group (R) may be substituted with -SiX3 (X is as defined above).

[0025] The hydrolyzable group refers to a substituent that can generate a silanol group by hydrolysis, and examples of the hydrolyzable group include a halogen atom, an alkoxy group, an acyloxy group, an alkenyloxy group, a carbamoyl group, an amino group, an aminooxy group, and a ketoximate group.

[0026] The organic group includes an alkyl group, an aryl group, or an aralkyl group. However, at least one of the organic groups must have a sulfur atom or a nitrogen atom. The silane coupling agent has an organic functional group containing a sulfur atom or a nitrogen atom and a silanol group, so that the antibacterial substrate can have sufficient antibacterial properties and durability.

[0027] The organic functional group containing a sulfur atom or a nitrogen atom includes an organic group in which at least one hydrogen atom is substituted with a functional group containing a sulfur atom or a functional group containing a nitrogen atom (hereinafter sometimes referred to as a "first organic group"), and an organic group in which one or more sulfur atoms or nitrogen atoms are inserted between the carbon atoms of the organic group (hereinafter sometimes referred to as a "second organic group").

[0028] Among the first organic groups, the functional group containing a sulfur atom includes a mercapto group, and the functional group containing a nitrogen atom includes an amino group, an isocyanurate group, and a ureido group.

[0029] Examples of silane coupling agents having an organic group having a mercapto group include mercaptoalkylalkoxysilanes such as (3-mercaptopropyl)trimethoxysilane. When the organic functional group containing a sulfur atom is a mercapto group, the dispersion is less likely to precipitate, and an antibacterial substrate having sufficient antibacterial properties can be obtained by applying the dispersion to a substrate. Furthermore, the antibacterial metal particles contained in the dispersion can be sufficiently prevented from becoming finer over time. In addition, the dispersion has a sufficiently small effect on the color of the substrate, and the antibacterial substrate obtained by using this dispersion has sufficient durability.

[0030] Examples of silane coupling agents having an organic group having an amino group include 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane.

[0031] An example of a silane coupling agent having an isocyanurate group is tris(trimethoxysilylpropyl)isocyanurate.

[0032] An example of a silane coupling agent having an organic group having a ureido group is 3-ureidopropyltrialkoxysilane.

[0033] The second organic group may have a sulfide group, i.e., one sulfur atom inserted between carbon atoms (-S-), or two or more sulfur atoms inserted (-SS-, -SSS-, -SSSS-, etc.). The second organic group may also have one nitrogen atom inserted between carbon atoms (-NR 1 -, R 1 is a hydrogen atom or an organic group).

[0034] Examples of silane coupling agents having an organic group having a sulfide group include bis-(3-triethoxysilylpropyl)-disulfide and bis-(3-triethoxysilylpropyl)-tetrasulfide.

[0035] The dispersion liquid according to the embodiment may contain 0.00000035 to 0.1 mass %, or 0.000005 to 0.005 mass %, of a silane coupling agent having an organic functional group containing a sulfur atom or a nitrogen atom, based on the total amount of the dispersion liquid.

[0036] The mass ratio of the silane coupling agent having an organic functional group containing a sulfur atom or a nitrogen atom to the antibacterial metal particles (mass of the silane coupling agent / mass of the metal particles) is 0.007 to 2. The above ratio can also be 0.01 to 1, 0.05 to 0.5, or 0.07 to 0.3. When the mass ratio of the silane coupling agent to the antibacterial metal particles is within the above range, the dispersion is less likely to cause precipitation, and an antibacterial substrate having sufficient antibacterial properties can be obtained by applying the dispersion to a substrate. Furthermore, the antibacterial metal particles contained in the dispersion can be prevented from becoming finer over time. In addition, the dispersion has little effect on the color of the substrate, the antibacterial substrate obtained using this dispersion has sufficient durability, and the bonded body obtained using this dispersion has sufficient antibacterial properties and adhesive strength.

[0037] The medium of the dispersion liquid according to the embodiment may be any medium capable of dispersing the submicron-sized antibacterial metal particles and the silane coupling agent having an organic functional group containing a sulfur atom or a nitrogen atom. The medium is preferably a polar solvent, and examples thereof include water, alcohol (methanol, ethanol, isopropanol, etc.), acetone, and other polar organic solvents. The medium is preferably water.

[0038] The dispersion according to the embodiment may contain 0.00005 to 0.15 mass %, 0.0001 to 0.05 mass %, or 0.005 to 0.03 mass % of the medium based on the total amount of the dispersion.

[0039] In the dispersion according to the embodiment, the silane coupling agent having an organic functional group containing a sulfur atom or a nitrogen atom and the submicron-sized antibacterial metal particles may be present separately, or at least a part of the silane coupling agent having an organic functional group containing a sulfur atom or a nitrogen atom may be bonded or attached to the submicron-sized antibacterial metal particles. In the latter case, the organic functional group or hydrolyzable group containing a sulfur atom or a nitrogen atom of the silane coupling agent can be bonded to the submicron-sized antibacterial metal particles by chemical or coordinate bonds.

[0040] In the method for producing an antibacterial substrate according to the embodiment, the above-mentioned dispersion (antibacterial dispersion) is brought into contact with a substrate.

[0041] The substrate may be made of, for example, an inorganic material such as glass or ceramic, an organic material such as wood or natural fiber, a metal, or a thermosetting or thermoplastic resin. Since the antibacterial substrate can be produced under mild conditions, it is possible to obtain an antibacterial substrate in which deterioration of the substrate is suppressed even if the substrate is made of resin.

[0042] The shape of the substrate may be fibrous, spherical, plate-like, film-like, polyhedral, or a three-dimensional shape having a three-dimensional curved surface. When the substrate is fibrous, the antibacterial metal particles penetrate between the fibers of the substrate when the substrate is contacted with the dispersion liquid, so that the amount of the antibacterial metal particles attached can be increased, and thus an antibacterial substrate having higher durability can be produced. The shape, size, and material of the substrate can be arbitrarily combined. For example, a fibrous resin material may be used as the substrate.

[0043] When the substrate has a surface made of metal or ceramic, it is preferable to wash the surface of the substrate before contacting with the dispersant. Examples of the washing method include ozone treatment, plasma treatment, ultrasonic washing, solvent washing, etc. In this case, the antibacterial substrate can be produced more efficiently, and the obtained antibacterial substrate has more sufficient antibacterial properties and durability.

[0044] When the substrate has a surface made of a resin, it is preferable to hydrophilize the surface of the substrate before contacting the dispersion. This hydrophilization treatment generates a sufficient number of hydroxyl groups on the substrate surface, so that the silane coupling agent having an organic functional group containing a sulfur atom or a nitrogen atom and the hydrophilized surface are more strongly bonded, and the antibacterial layer formed on the substrate is stronger. In addition, an antibacterial substrate exhibiting excellent antibacterial properties can be obtained more efficiently, and the obtained antibacterial substrate has more sufficient antibacterial properties and durability. Examples of hydrophilization methods include ozone treatment, oxygen plasma treatment, hydrophilic coating, and the like. For example, when the surface of the substrate is made of polyester, the hydrophilization treatment can be performed by washing with an aqueous sodium hydroxide solution. In addition, if the resin is highly hydrophilic, the same effect can be obtained without hydrophilization treatment. Examples of highly hydrophilic resins include polylactic acid and nylon.

[0045] The method for contacting the substrate with the dispersion liquid is arbitrary, and for example, the substrate can be contacted with the dispersion liquid by coating, spraying, immersion, etc. In this case, the state of the dispersion liquid is liquid, droplets, mist, etc. When the substrate is immersed in the dispersion liquid, an antibacterial substrate having sufficient antibacterial properties and durability can be produced by a simpler method.

[0046] When or after contacting the substrate with the dispersion, at least a part of the volatile matter of the dispersion may be removed. In this case, an antibacterial substrate having sufficient antibacterial properties and durability and little effect of the dispersion on color can be obtained. Furthermore, the antibacterial substrate can be produced efficiently in a shorter time.

[0047] The volatile components include the medium contained in the dispersion liquid, as well as molecules generated during hydrolysis or condensation of the silane coupling agent having an organic functional group containing a sulfur atom or a nitrogen atom.

[0048] Methods for removing volatile matters include natural drying, heat treatment, reduced pressure heat treatment, reduced pressure treatment, etc. The temperature for removing volatile matters is preferably 25 to 120°C or less, more preferably 70°C to 110°C or less. By setting the removal temperature at 70°C or more, the treatment time can be shortened. Although there is no problem if the removal temperature is 120°C or more, by setting the removal temperature at 120°C or less, deterioration of the product due to heat can be suppressed.

[0049] The method for producing a bonded body according to the embodiment includes a step of bonding a first base material and a second base material that face each other.

[0050] The manufacturing method of the bonded body according to the embodiment is a manufacturing method of a bonded body in which a first substrate and a second substrate facing each other are bonded, and at least one of the first substrate and the second substrate has a hydrophilic resin substrate facing each other, and a layer made of the above-mentioned dispersion is formed on at least one of the facing surfaces (preferably on the surface of the hydrophilic resin substrate) to bond them. At least one of the first substrate and the second substrate may have a hydrophilized resin substrate facing each other, and a layer made of the above-mentioned dispersion may be formed on the hydrophilized surface of the substrate to bond them. In carrying out the manufacturing method of the bonded body, it is preferable to bond the facing surfaces together using an adhesive, and it is preferable to use an adhesive that generates hydrogen bonds or chemical reactions with the hydrophilic groups on the hydrophilized surface. For example, when active hydrogen groups such as hydroxyl groups are generated on the surfaces as a result of hydrophilization, an adhesive that can react with active hydrogen, such as an epoxy adhesive or a urethane adhesive, can be used.

[0051] The hydrophilic resin substrate includes a substrate made of a resin (polylactic acid, nylon, etc.) to which the non-volatile components of the dispersion liquid are sufficiently attached even without hydrophilization treatment, and a substrate made of a hydrophilized resin. At least one of the opposing first substrate and second substrate can be a resin substrate whose opposing surface is hydrophilized. The other substrate may be a resin substrate whose opposing surface is hydrophilized like the one substrate, or a substrate made of another material. The first substrate and the second substrate may be made of the same or different materials. Examples of the other material include inorganic materials such as ceramics, organic materials such as wood or natural fibers, and metals. In addition, when both the first substrate and the second substrate have a resin surface, it is preferable that both the first substrate and the second substrate have their opposing surfaces hydrophilized.

[0052] The shape of the first substrate and the second substrate may be a fiber shape, a sphere shape, a plate shape, a film shape, a polyhedron shape, a three-dimensional shape having a three-dimensional curved surface, etc. The shape of the first substrate and the second substrate may be the same or different from each other. One substrate may be folded, etc., to form the opposing surfaces.

[0053] Methods for hydrophilizing the surface of a resin substrate include ozone treatment, oxygen plasma treatment, hydrophilic coating, etc. For example, when the resin is polyester, the surface of the substrate can be hydrophilized by washing with an aqueous sodium hydroxide solution.

[0054] When a bonded body is manufactured by hydrophilizing a substrate, a layer made of the above-mentioned dispersion is formed on the hydrophilized surface of the substrate, and bonding is performed. The layer made of the dispersion can be formed by contacting at least one of the opposing surfaces of the first substrate or the second substrate with the dispersion. Before bonding, at least a part or all of the volatile content of the dispersion formed on the hydrophilized surface may be volatilized, or bonding may be performed without volatilization. That is, the layer made of the dispersion may be a layer made of the dispersion from which at least a part or all of the volatile content of the dispersion has been volatilized, or a layer made of the dispersion from which the volatile content has not been volatilized.

[0055] In the above-mentioned manufacturing method, the above-mentioned dispersion of the embodiment is used, and since this dispersion exhibits sufficient antibacterial properties even when the concentration of the antibacterial component is low, when a layer made of the dispersion is formed on a substrate, the hydrophilic groups affected by the antibacterial component are reduced. In other words, even if antibacterial properties are imparted, the hydrophilic groups on the substrate surface remain sufficiently, so that when an adhesive that forms hydrogen bonds or chemical reactions with the hydrophilic groups is used, the bonded body has sufficient adhesive strength. EXAMPLES

[0056] First, 100 mL of water was placed in a beaker, and 0.5 g of glacial acetic acid was dissolved to obtain an aqueous acetic acid solution. 0.1 mg of (3-mercaptopropyl)trimethoxysilane (manufactured by Kanto Chemical Co., Ltd.) was added to this aqueous acetic acid solution, and the solution was thoroughly stirred. Furthermore, 0.1 mL of a 0.16 g / mL% aqueous silver nitrate solution was added to the above solution. Then, 0.1 mL of a 0.1 g / mL% aqueous sodium borohydride solution was added, and the entire solution was stirred until it became uniform. At this time, since the solution after stirring was brown, it was confirmed that a silver colloid in which submicron-sized silver particles were dispersed in the solution was obtained. In this way, the dispersion liquid according to Example 1 was obtained.

[0057] Dispersions according to Examples 2 to 9 and Comparative Examples 1 to 16 were obtained in the same manner as in Example 1, except that the amounts of the mercaptosilane aqueous solution, the silver nitrate aqueous solution, and the sodium borohydride aqueous solution were changed to the amounts shown in Table 1.

[0058] The stability of the dispersions according to the Examples and Comparative Examples was evaluated as follows. That is, first, 50 mL of the dispersion according to the examples and comparative examples was placed in a 100 mL beaker. The dispersion was left to stand at room temperature for three days, and then the state of the dispersion was observed to evaluate the stability of the dispersion. The results are shown in Table 1.

[0059] The evaluation criteria were as follows: if the entire dispersion was transparent, it was rated as "transparent", if a faint precipitate was visible at the bottom of the container, it was rated as "partial precipitate", if a precipitate was clearly visible at the bottom of the container, it was rated as "precipitation", and if none of the above applied and the entire dispersion was brown and transparent, it was rated as "dispersed".

[0060] The dispersions of Examples 1 to 9 and Comparative Examples 2 to 4, which were evaluated as "dispersed" in terms of stability, were used to prepare antibacterial substrates of Examples 1 to 9 and Comparative Examples 2 to 4. The substrate used was a glass cloth (WEA 22F, manufactured by Nitto Boseki Co., Ltd.) from which bundling materials and the like sprayed during glass fiber production had been removed by heat treatment.

[0061] Specifically, a test substrate was prepared by cutting a 0.2 mm thick glass cloth into a size of 3 cm length and 3 cm width. Next, the entire test substrate was immersed in the dispersion liquid and then taken out within 30 seconds. After that, the glass cloth placed on a petri dish was left to stand at room temperature for 60 minutes or more to dry naturally. Furthermore, the test substrate was heated under conditions of 110°C and 10 minutes. Finally, the substrate was placed in 1 L of pure water and ultrasonically cleaned for 30 minutes under conditions of 40 kHz and 600 W to shake off the silver particles weakly adsorbed on the surface of the test substrate. In this way, antibacterial substrates according to Examples 1 to 9 and Comparative Examples 2 to 4 were obtained.

[0062] The effect of the dispersion on the color of the antibacterial substrates according to Examples 1 to 9 and Comparative Examples 2 to 4 was evaluated by visually comparing the color of the substrate with that of an untreated glass cloth. The results are shown in Table 1. The evaluation criteria were as follows: no change in color compared to the untreated glass cloth was rated as "no coloring" and a change in color was rated as "discoloration."

[0063] The antibacterial properties of the antibacterial substrates according to the examples and comparative examples were evaluated. The sterilization rate was used as an index of the antibacterial properties.

[0064] Specifically, first, a test specimen was cut out from the antibacterial substrate prepared by the above method, measuring 1 cm in length and 1 cm in width. At the same time, a comparison sample was also cut out from an untreated glass cloth measuring 1 cm in length and 1 cm in width. The same operation as that performed on the test specimen was also performed on the comparison sample at the same time. Next, the test specimen was placed in the center of a petri dish, and 10 μL of Escherichia coli K-12 strain bacterial liquid was dropped onto the center of the test specimen. Then, the petri dish was covered with a lid to prevent the inclusion of impurities, and the specimen was left to stand at room temperature (25°C ± 3°C) for 1 hour. Finally, the test specimen was washed with 1 mL of water after the standing to wash out the bacterial liquid. Furthermore, the washed-out bacterial liquid was seeded on an agar medium and cultured at 37°C for 24 hours, and the number of colonies was counted. The same experiment was performed three times, and the average number of colonies counted was used as the measurement result.

[0065] The average number of colonies derived from the bacterial liquid washed from the test piece obtained in the above experiment is A S The average number of colonies derived from the bacterial liquid washed out from the comparison sample is B ref Then, the sterilization rate of such an antibacterial substrate can be calculated by the following formula (1). Eradication rate (%)=(B ref -A S ) / B ref ×100 (1) The sterilization rates of the antibacterial substrates according to the examples and comparative examples are shown in Table 1.

[0066] A fiberglass reinforced plastic (FRP) plate was produced by hand lay-up molding. Specifically, a 3 mm thick spacer and a film coated with a release agent were placed in a flat mold, 14 layers of resin-impregnated glass cloth were laminated on top of that, and wrapped in a film coated with a release agent, and excess resin was pushed out using a roller to remove voids. After that, a hydraulic molding machine was used to pressurize and heat the material under conditions of 2.15 MPa, 35°C, for 20 minutes, and then pressurized and heated under conditions of 2.15 MPa, 80°C, for 3 hours to form a 3 mm thick FRP plate. The resin used was a mixture of 100 parts by weight of unsaturated polyester resin (Rigolac 158BQTN-1, manufactured by Resonac Corporation) and 1 part by weight of a hardener (Permec (registered trademark) N, manufactured by NOF Corporation). The glass cloth was a 0.2 mm thick glass cloth (WEA 22F 105 BS N, manufactured by Nitto Boseki Co., Ltd.). The film was a PET film (SP-PET-50-01-BU, manufactured by Mitsui Chemicals Tocello Inc.). The release agent was a silicone (Si)-based release agent (silicone spray KF96SP, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0067] The molded FRP plate was cut along the fiber direction of the glass cloth into a size of 100 mm length, 25 mm width and 3 mm thickness to obtain an FRP test piece.

[0068] The FRP test piece was immersed in a 3 mol / L NaOH aqueous solution at 85°C for 24 hours, and then washed twice with pure water to perform a hydrophilic treatment. Furthermore, the hydrophilic treated FRP test piece was immersed in the dispersion liquid according to Example 5 for 30 seconds, and then placed in a drying oven at 100°C and dried for 3 hours to perform an antibacterial coating, thereby obtaining an antibacterial FRP test piece according to Example 10.

[0069] Two antibacterial FRP test pieces according to Example 10 were prepared by the above-mentioned method, and were bonded together to prepare a joint. The two antibacterial FRP test pieces in the joint were arranged in a cross shape. That is, the two antibacterial FRP test pieces were stacked so that their planes of 100 mm length and 25 mm width were in contact, and then one of the antibacterial FRP test pieces was rotated 90° around a straight line that passed through the center of the plane and was perpendicular to the plane. The bonding surface was the part where the two antibacterial FRP test pieces were in contact, that is, the size of 25 mm length and 25 mm width.

[0070] Specifically, a fast-curing, room-temperature-curing, two-part epoxy resin (2086M, manufactured by ThreeBond Co., Ltd.) was applied to the adhesive surface of one of the antibacterial FRP test pieces, and then the other antibacterial FRP test piece was placed on top of it in the above-mentioned positional relationship, and the antibacterial FRP test piece was naturally dried for 12 hours to produce an antibacterial FRP test piece. The amount of adhesive applied was set so that the thickness of the adhesive after heating was 300 μm. In this way, a joint for a cross peel strength test according to Example 10 was obtained.

[0071] A joint for a tensile shear adhesion test of Example 10 was obtained in the same manner as the joint for a cross peel strength test of Example 10, except that the positional relationship of the two antibacterial FRP test pieces was such that the two antibacterial FRP test pieces were overlapped so that their flat surfaces of 100 mm length and 25 mm width were in contact, and then one of the antibacterial FRP test pieces was translated in the longitudinal direction until the longitudinal length of the overlapping part of the two antibacterial FRP test pieces reached 12.5 mm. The size of the adhesive surface of the joint for a tensile shear adhesion test was 12.5 mm length and 25 mm width.

[0072] An antibacterial FRP test piece, a joint for a cross peel strength test, and a joint for a tensile shear adhesion test of Example 11 were obtained in the same manner as in Example 10, except that a fluorine (F)-based release agent (Daifree GW-4000, manufactured by Daikin Industries, Ltd.) was used as the release agent.

[0073] An antibacterial FRP test piece, a joint for a cross peel strength test, and a joint for a tensile shear adhesion test of Example 12 were obtained in the same manner as in Example 10, except that a resin prepared by mixing 100 parts by mass of an in-situ polymerized thermoplastic acrylic resin (Elium (registered trademark) 190 AP, manufactured by Arkema K.K.) with 1 part by mass of a hardener (Perloil (registered trademark) TCP, manufactured by NOF Corporation) was used as the resin, and the pressurized heating in molding the FRP plate was performed under conditions of 2.15 MPa, 40°C, and 3 hours, and then under conditions of 2.15 MPa, 80°C, and 1 hour.

[0074] An antibacterial FRP test piece, a joint for a cross peel strength test, and a joint for a tensile shear adhesion test of Example 13 were obtained in the same manner as in Example 12, except that a fluorine (F)-based release agent (Daifree GW-4000, manufactured by Daikin Industries, Ltd.) was used as the release agent.

[0075] A joint for a cross peel strength test and a joint for a tensile shear adhesion test according to Comparative Example 17 were obtained in the same manner as in Example 10, except that the hydrophilic treatment and antibacterial coating steps were omitted.

[0076] A joint for a cross peel strength test and a joint for a tensile shear adhesion test according to Comparative Example 18 were obtained in the same manner as in Example 11, except that the hydrophilic treatment and antibacterial coating steps were omitted.

[0077] A joint for a cross peel strength test and a joint for a tensile shear adhesion test according to Comparative Example 19 were obtained in the same manner as in Example 12, except that the hydrophilic treatment and antibacterial coating steps were omitted.

[0078] A joint for a cross peel strength test and a joint for a tensile shear adhesion test according to Comparative Example 20 were obtained in the same manner as in Example 13, except that the hydrophilic treatment and antibacterial coating steps were omitted.

[0079] The adhesive strength was evaluated using the cross peel strength test joints and the tensile shear adhesion test joints of Examples 10 to 13 and Comparative Examples 17 to 20, using a universal testing machine (AG-1 ​​manufactured by Shimadzu Corporation). The cross peel strength and the tensile shear adhesive strength were used as indicators of adhesive strength. Each evaluation was performed using five joints produced under the same conditions, and the average value was calculated.

[0080] A cross peel strength test was carried out on the joints for the cross peel strength test according to Examples 10 to 13 and Comparative Examples 17 to 20, and the maximum load [N] at which the joint broke was measured. The maximum load was divided by the bonding width of 25 mm to calculate the cross peel strength. The measurement conditions were that the tensile direction was perpendicular to the bonding surface and in the direction in which the two FRP test pieces separated, and the test speed was 1 mm / min. The results are shown in Table 2.

[0081] A tensile shear adhesive strength test was carried out on the joints for the shear adhesive test according to Examples 10 to 13 and Comparative Examples 17 to 20, and the maximum load [N] at which the joint broke was measured. 2 The tensile shear adhesive strength was calculated by dividing the measured value by the tensile strength. The measurement conditions were in accordance with JIS K 6850, and the tensile speed was 0.2 mm / min. The results are shown in Table 2.

[0082] [Table 1]

[0083] [Table 2]

[0084] In Table 2 above, "UP" is "unsaturated polyester resin," "PMMA" is "acrylic resin (polymethyl methacrylate)," "Si-based" is "silicone-based release agent," and "F-based" is "fluorine-based release agent."

[0085] From the results shown in Table 1, it was confirmed that the dispersions according to Examples 1 to 9 maintained the metal colloid because no precipitation occurred and the color was brown even after being left for 3 days. It was also confirmed that the use of the dispersions according to Examples 1 to 9 allowed the formation of antibacterial substrates that had sufficient antibacterial properties with a sterilization rate of 65% or more and were not affected by the color of the dispersion.

[0086] On the other hand, the dispersions of Comparative Examples 1, 6, 8, 10, and 12, in which the mass ratio of the silane coupling agent to the antibacterial metal particles was 2 or more, were evaluated as “transparent” in terms of stability, and it was confirmed that the silver particles became finer over time due to dissolution and reprecipitation, and that the metal colloid necessary for antibacterial properties was not maintained.

[0087] In addition, the stability evaluation results for the dispersions of Comparative Examples 5, 7, 9, and 11, in which the mass ratio of silane coupling agent to antibacterial metal particles was 0.007 or less, and the dispersions of 13 to 16, in which the content of antibacterial metal particles was 0.05 mass% or more based on the total amount of the dispersion, were "precipitation" or "partial precipitation," confirming that precipitation of the antibacterial metal particles had occurred.

[0088] The antibacterial substrates according to Comparative Examples 2 to 4, in which the content of antibacterial metal particles was 0.00005% by mass or less based on the total amount of the dispersion liquid, had a sterilization rate of 20.5% or less, and were therefore confirmed to not have sufficient antibacterial properties.

[0089] From the results shown in Table 2, it was confirmed that the bonded structures of Examples 10 to 13 had higher cross peel strength and tensile shear adhesive strength and had excellent adhesive strength compared to Comparative Examples 17 to 20 which were produced under the same conditions except that the hydrophilic treatment and antibacterial coating were omitted.

[0090] From the above, it was confirmed that the dispersion of the present disclosure is unlikely to cause precipitation, and when applied to a substrate, an antibacterial substrate having sufficient antibacterial properties can be formed. Furthermore, it was confirmed that this dispersion can suppress the antibacterial metal particles contained in the dispersion from becoming finer over time, and has little effect on the color of the substrate. In addition, it was confirmed that the bonded body obtained using this dispersion has sufficient adhesive strength.

Claims

1. A dispersion comprising submicron-sized antibacterial metal particles and a silane coupling agent in a medium, The content of the antibacterial metal particles is 0.00005 to 0.05% by mass based on the total amount of the dispersion, The silane coupling agent has an organic functional group containing a sulfur atom or a nitrogen atom, A dispersion liquid in which the mass ratio of the silane coupling agent to the antibacterial metal particles is 0.007 to 2.

2. 2. The dispersion according to claim 1, wherein the antibacterial metal particles are particles formed by reducing antibacterial metal ions in the medium with a reducing agent.

3. The dispersion of claim 1 , wherein the antimicrobial metal particles are silver particles.

4. The dispersion according to claim 1 , wherein the organic functional group containing a sulfur atom is an organic functional group having a mercapto group.

5. 2. The dispersion according to claim 1, wherein the content of the antibacterial metal particles is 0.0005 to 0.005% by mass based on the total amount of the dispersion.

6. 2. The dispersion according to claim 1, wherein a mass ratio of the silane coupling agent to the antibacterial metal particles is 0.05 to 0.

5.

7. 1. A method for producing an antibacterial substrate by contacting a substrate with an antibacterial dispersion, comprising: The method of claim 1 , wherein the antibacterial dispersion is a dispersion according to any one of claims 1 to 6.

8. The method according to claim 7, wherein the substrate is contacted with the antibacterial dispersion to remove at least a portion of the volatile matter of the antibacterial dispersion at 25 to 120°C.

9. The method of claim 7 , wherein the substrate is contacted with the antibacterial dispersion by immersing the substrate in the antibacterial dispersion.

10. The method according to claim 7 , wherein the substrate is a resin substrate or a fibrous substrate.

11. A method for manufacturing a bonded body for bonding a first base material and a second base material facing each other, comprising the steps of: At least one of the first substrate and the second substrate has an opposing surface which is a hydrophilic resin substrate, A method for producing a bonded body, comprising forming a layer made of the dispersion liquid according to any one of claims 1 to 6 on at least one of the opposing surfaces, and then bonding the surfaces.

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