Metal Nanoparticle-Supported Polymer, Composition, Article, and Method for Producing the Polymer

Abstract

To provide a metal nanoparticle-carrying polymer that is soluble in water or organic solvent and suppresses coloration in solution.MEANS FOR SOLVING THE PROBLEM: A metal nanoparticle-carrying polymer contains an uncrosslinked organic polymer backbone having a side chain containing a charging group, and metal nanoparticles supported on the uncrosslinked organic polymer backbone. A solution of the metal nanoparticle-carrying polymers (0.01 mass%) in water has an absorbance of 0.100 or less at a wavelength of 350 nm or more and 750 nm or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a metal nanoparticle-supported polymer, a composition containing the polymer, an article containing the composition, and a method for producing a metal nanoparticle-supported polymer.

Background Art

[0002] It has long been known that metal ions typified by silver ions have antibacterial properties. Recently, metal ions having antiviral properties have also become known. Similar effects have also been reported in metal nanoparticles such as silver nanoparticles and platinum nanoparticles. Components having antibacterial and / or antiviral properties (hereinafter also referred to as "antibacterial and antiviral agents") using metal nanoparticles are expected to increase more and more in the future. In addition to such uses, metal nanoparticles can be used for various applications. Conventionally, methods for supporting metal nanoparticles on organic polymers have been studied (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present inventors have studied a metal nanoparticle-supported polymer in which metal nanoparticles are supported on an organic polymer backbone. As a result, the present inventors have found that when a metal nanoparticle-supported polymer is dissolved in a solvent, coloring presumably caused by the metal nanoparticles is observed. Such coloring may make it difficult to develop a metal nanoparticle-supported polymer for applications that require, for example, colorless transparency.

[0005] This disclosure aims to provide a metal nanoparticle-supported polymer that is soluble in water or an organic solvent and has suppressed coloring in solution. Another object of this disclosure is to provide a method for producing such a metal nanoparticle-supported polymer, a composition containing the polymer, and an article containing the composition.

Means for Solving the Problems

[0006] The present inventors have conducted studies to solve the above problems. As a result, the present inventors have found that by supporting metal complex ions on a non-crosslinked organic polymer and then appropriately reducing the supported metal complex ions to form metal nanoparticles, a metal nanoparticle-supported polymer with suppressed coloring in solution can be obtained.

[0007] The metal nanoparticle-supported polymer of the present disclosure is a metal nanoparticle-supported polymer comprising a non-crosslinked organic polymer backbone having a side chain containing a charged group and metal nanoparticles supported on the non-crosslinked organic polymer backbone, wherein the absorbance of an aqueous solution of the metal nanoparticle-supported polymer at a concentration of 0.01% by mass in the wavelength range of 350 nm or more and 750 nm or less is 0.100 or less. The composition of the present disclosure contains the above metal nanoparticle-supported polymer. The article of the present disclosure contains the above composition. The method for producing a metal nanoparticle-supported polymer of the present disclosure includes: (1) a step of preparing a non-crosslinked organic polymer having a side chain containing a charged group, a metal salt, and a complexing agent; (2) a step of dissolving the non-crosslinked organic polymer, the metal salt, and the complexing agent in water to obtain a metal complex ion-supported polymer in which metal complex ions are supported on the non-crosslinked organic polymer; and (3) a step of reducing the metal complex ions in the metal complex ion-supported polymer to form metal nanoparticles supported on the non-crosslinked organic polymer.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to provide a metal nanoparticle-supported polymer that is soluble in water or an organic solvent and has suppressed coloring in solution. Further, according to the present disclosure, it is possible to provide a method for producing such a metal nanoparticle-supported polymer, a composition containing the polymer, and an article containing the composition.

Brief Description of Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0010] In the present disclosure, "antibacterial property" refers to the property of killing or damaging either or both of bacteria and fungi, or the property of continuously suppressing the growth and proliferation of either or both of bacteria and fungi. Examples of bacteria include staphylococcus, Escherichia coli, Salmonella, Pseudomonas aeruginosa, Vibrio cholerae, Shigella, Bacillus anthracis, Mycobacterium tuberculosis, Clostridium botulinum, Clostridium tetani, and Streptococcus. Examples of fungi (or molds) include Trichophyton, Candida, and Aspergillus.

[0011] In the present disclosure, "antiviral property" refers to the property of inactivating a virus by denaturing or damaging the proteins constituting the capsid or envelope of the virus. Examples of the virus include norovirus, influenza virus, adenovirus, coronavirus, measles virus, rubella virus, hepatitis virus, herpes virus, and HIV.

[0012] [Polymer Supported Metal Nanoparticles] The metal nanoparticle-supported polymer of the present disclosure (hereinafter also referred to as "the polymer of the present disclosure") comprises a non-crosslinked organic polymer backbone having a side chain containing a charged group, and metal nanoparticles supported on the non-crosslinked organic polymer backbone. and contains

[0013] The absorbance of the polymer of the present disclosure in an aqueous solution with a concentration of 0.01% by mass in the wavelength range of 350 nm or more and 750 nm or less is 0.100 or less. Since the polymer of the present disclosure exhibits such an extremely low absorbance, it can be suitably used for various applications.

[0014] <Non-crosslinked Organic Polymer Skeleton> The polymer of the present disclosure includes a non-crosslinked organic polymer backbone. Hereinafter, when describing the non-crosslinked organic polymer as a molecule, it will be simply referred to as "non-crosslinked polymer", and when describing it as a component of the polymer of the present disclosure, it will be referred to as "non-crosslinked polymer backbone".

[0015] The non-crosslinked polymer functions as a carrier for metal nanoparticles and metal complex ions described later. In the present disclosure, the non-crosslinked polymer means a polymer having no three-dimensional crosslinked structure, and is usually a chain polymer such as a linear polymer and a branched-chain polymer. The non-crosslinked polymer has no physical or chemical crosslinked structure in a solvent, for example. Therefore, the polymer of the present disclosure containing a non-crosslinked polymer backbone is soluble in water or a predetermined organic solvent. Here, "soluble" means, for example, that when 1 g of the polymer is added to 100 mL of the solvent at room temperature (25 °C), it does not become cloudy, settle, or gel. By using the polymer of the present disclosure containing a non-crosslinked polymer backbone, a transparent composition can be prepared or a transparent film can be formed.

[0016] The non-crosslinked polymer has a side chain containing a charged group. The charged group is a group that can be negatively or positively charged (ionized) in water, and is, for example, a proton-donating group (Bronsted acid) or a proton-accepting group (Bronsted base). Thereby, in water, the molecular chain of the non-crosslinked polymer is negatively or positively charged, the entanglement of the molecular chains of the non-crosslinked polymer is loosened by electrostatic repulsion, and at the same time, the charged group or a binding group described later is exposed in water. The metal nanoparticles described later are bound to the exposed charged group or binding group. The binding group may be the same as or different from the charged group.

[0017] Examples of the charged group include anionic groups (charged groups that can be negatively charged in water) such as carboxy groups and sulfo groups, and cationic groups (charged groups that can be positively charged in water) such as amino groups. Among these, anionic groups such as carboxy groups and sulfo groups are preferable, and carboxy groups are more preferable. The charged group includes a group that is negatively or positively charged (ionized). For example, when the charged group is a carboxy group, the charged group includes carboxylate ions.

[0018] The side chain may be the charged group itself.

[0019] The chargeable group contained in the non-crosslinked polymer is preferably only one of an anionic group or a cationic group. For example, in the case of a non-crosslinked polymer having a side chain containing a carboxy group, it is preferable that the non-crosslinked polymer does not have a side chain containing an amino group, and in the case of a non-crosslinked polymer having a side chain containing an amino group, it is preferable that the non-crosslinked polymer does not have a side chain containing a carboxy group.

[0020] The content of the chargeable group in the non-crosslinked polymer is preferably 0.1 mmol / g or more and 100 mmol / g or less, more preferably 0.5 mmol / g or more and 50 mmol / g or less, and still more preferably 1 mmol / g or more and 20 mmol / g or less. When the content of the chargeable group is within the above range, the entanglement of the molecular chains of the non-crosslinked polymer can be sufficiently loosened by electrostatic repulsion in water, and the non-crosslinked polymer can sufficiently hold the metal nanoparticles and the metal complex ions described later by the chargeable groups.

[0021] The chargeable group is preferably uniformly distributed over the entire molecular chain of the non-crosslinked polymer. When the side chains containing the chargeable groups are unevenly distributed within the molecular chain, the solubility of the non-crosslinked polymer in water may decrease or the loading amount of the metal nanoparticles may decrease.

[0022] The non-crosslinked polymer having a side chain containing a chargeable group can be obtained, for example, by homopolymerizing or copolymerizing a monomer containing a chargeable group. Examples of the non-crosslinked polymer having a side chain containing a chargeable group include vinyl polymers, polysaccharides, and proteins having a repeating structural unit containing a chargeable group. Among these, vinyl polymers having a repeating structural unit containing a chargeable group are preferable.

[0023] In the above non-crosslinked polymer, the content ratio of the repeating structural unit containing a chargeable group is preferably 50 mol% or more, more preferably 60 mol% or more, and still more preferably 70 mol% or more in all the repeating structural units. In the present disclosure, the content ratio of the above structural unit can be determined by NMR.

[0024] Examples of the vinyl polymer having a repeating structural unit containing a charged group include a homopolymer or copolymer of an ethylenically unsaturated monomer containing a charged group, and a copolymer of an ethylenically unsaturated monomer containing a charged group and an ethylenically unsaturated monomer not containing a charged group.

[0025] Examples of the ethylenically unsaturated monomer containing a charged group include carboxy group-containing monomers such as (meth)acrylic acid, crotonic acid, β-carboxyethyl (meth)acrylate, maleic acid, itaconic acid, fumaric acid, and citraconic acid, and anhydrides of unsaturated dicarboxylic acids such as maleic anhydride and itaconic anhydride; and sulfo group-containing monomers such as vinylsulfonic acid and p-styrenesulfonic acid.

[0026] Examples of the ethylenically unsaturated monomer not containing a charged group include styrenes, vinyl alkanoates, vinyl aromatic carboxylates, and (meth)acrylates.

[0027] Examples of the styrenes include styrene, methylstyrene, vinyltoluene, vinyl ethylbenzene, and vinylnaphthalene. Examples of the vinyl alkanoates include vinyl acetate, vinyl propionate, and vinyl butyrate. Examples of the vinyl aromatic carboxylates include vinyl benzoate.

[0028] Examples of the (meth)acrylates include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate; alicyclic or aromatic ring-containing (meth)acrylates such as cyclohexyl (meth)acrylate, benzyl (meth)acrylate, and methylcyclohexyl (meth)acrylate; hydroxyl group-containing (meth)acrylates such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate; and glycidyl group-containing (meth)acrylates such as glycidyl (meth)acrylate.

[0029] In a copolymer of an ethylenically unsaturated monomer containing a charged group and an ethylenically unsaturated monomer not containing a charged group, the content ratio of the structural unit derived from the ethylenically unsaturated monomer containing a charged group is preferably 50 mol% or more, more preferably 60 mol% or more, and still more preferably 70 mol% or more in all the repeating structural units.

[0030] Specific examples of the vinyl polymer having a repeating structural unit containing a charged group include poly(meth)acrylic acid, polymaleic acid, polyitaconic acid, polyvinyl sulfonic acid, polystyrene sulfonic acid, (meth)acrylic acid-maleic acid copolymer, and (meth)acrylic acid-vinyl sulfonic acid copolymer, and metal salts thereof. Examples of the metal salts include sodium salts and potassium salts. Among these, poly(meth)acrylic acid and its metal salts are preferable, and polyacrylic acid and its metal salts are more preferable.

[0031] Examples of the polysaccharide having a repeating structural unit containing a charged group include polysaccharides having a repeating structural unit containing a carboxy group, and specific examples include carboxymethyl cellulose, carboxyethyl cellulose, carboxymethyl starch, carboxymethyl dextran, and alginic acid, and metal salts thereof. Examples of the metal salts include sodium salts and potassium salts.

[0032] Among these, carboxymethyl cellulose, alginic acid, and metal salts thereof are preferable, and carboxymethyl cellulose, sodium carboxymethyl cellulose, alginic acid, and sodium alginate are more preferable.

[0033] Proteins have repeating structural units consisting of amino acid residues. Examples of amino acids having side chains containing charged groups include acidic amino acids such as aspartic acid and glutamic acid, and basic amino acids such as lysine.

[0034] In a protein having an amino acid residue with a side chain containing a charged group, the ratio (number basis) of the amino acid residue with a side chain containing a charged group is preferably 50% or more, more preferably 60% or more, and still more preferably 70% or more among all amino acid residues.

[0035] Examples of proteins having amino acid residues with side chains containing charged groups include proteins of acidic amino acids such as polyaspartic acid and polyglutamic acid, and proteins of basic amino acids such as poly-L-lysine. Among these, poly-L-lysine is preferable.

[0036] Among non-crosslinked polymers having side chains containing charged groups, poly(meth)acrylic acid is preferable, and polyacrylic acid is more preferable.

[0037] As the non-crosslinked polymer having a side chain containing a charged group, a commercially available product may be used, or it may be synthesized by polymerizing a monomer by a conventionally known method. After obtaining a non-crosslinked polymer having no charged group by polymerizing a monomer not containing a charged group, a charged group may be introduced into the polymer. For example, carboxymethyl cellulose can be obtained by substituting part or all of the hydrogen atoms of the hydroxy group in the structure of cellulose or the hydrogen atoms bonded to the oxygen atom of the hydroxymethyl group with carboxymethyl groups. Further, as the non-crosslinked polymer having a side chain containing a charged group, an extract from a natural product such as sodium alginate may be used.

[0038] The weight average molecular weight (Mw) of the non-crosslinked polymer is preferably 1,000 or more and 1,000,000 or less, more preferably 2,000 or more and 100,000 or less, and even more preferably 5,000 or more and 30,000 or less. When Mw is below the upper limit value, it is preferable because aggregation of the non-crosslinked polymer in a solvent is suppressed. In the present disclosure, Mw is the weight average molecular weight in terms of polystyrene, which is determined by gel permeation chromatography (GPC) in accordance with JIS K7252-1 (2008).

[0039] The non-crosslinked polymer skeleton constituting the polymer of the present disclosure may have a hydrophobic group bonded to the above-mentioned chargeable group. That is, the non-crosslinked polymer skeleton may have a group in which a hydrophobic group is bonded to the above-mentioned chargeable group. Thereby, the solubility of the polymer of the present disclosure in an organic solvent is increased, and the miscibility with other polymers can be improved.

[0040] In one embodiment, the hydrophobic group is preferably introduced into the non-crosslinked polymer skeleton by esterification or amidation of the above-mentioned chargeable group. Examples of the group in which the hydrophobic group is bonded to the above-mentioned chargeable group include, when the chargeable group is a carboxy group or a sulfo group, a group represented by -CONHR, -COOR, or -SO2OR, and when the chargeable group is an amino group, a group represented by -NHCOR. Here, R is a hydrophobic group.

[0041] Examples of the hydrophobic group include hydrocarbon groups such as aliphatic hydrocarbon groups, alicyclic-containing hydrocarbon groups, and aromatic-ring-containing hydrocarbon groups. The number of carbon atoms of the hydrophobic group is preferably 4 or more and 18 or less. When the polymer of the present disclosure is dissolved in an organic solvent having a low polarity (dielectric constant) (such as toluene or cyclohexane), it is preferable that a larger number of carbon atoms of the hydrophobic group are bonded to the above-mentioned chargeable group.

[0042] Examples of the aliphatic hydrocarbon group include alkyl groups such as butyl group, hexyl group, 2-ethylhexyl group, octyl group, decyl group, hexadecyl group and octadecyl group; and alkenyl groups such as oleyl group. Examples of the alicyclic hydrocarbon group include cycloalkyl groups such as cyclohexyl group. Examples of the aromatic ring-containing hydrocarbon group include aralkyl groups such as benzyl group.

[0043] In the polymer of the present disclosure, among the above-mentioned chargeable groups, the proportion (in terms of moles) of the hydrophobic group bonded to the chargeable group is preferably 0.1% or more and 50% or less, more preferably 0.5% or more and 20% or less, and still more preferably 1% or more and 10% or less. In one embodiment, the above proportion is the proportion in which the chargeable group is esterified or amidated by the hydrophobic group. The above proportion can be measured by nuclear magnetic resonance method (NMR) or matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS).

[0044] Fig. 1 shows a schematic diagram of the polymer of the present disclosure. Fig. 1 is an example in which the non-crosslinked polymer is polyacrylic acid and the metal nanoparticles are silver nanoparticles. The metal nanoparticle-supported polymer 10 includes a non-crosslinked polymer skeleton 11 and metal nanoparticles 12 supported on the non-crosslinked polymer skeleton 11. A hydrophobic group 14 (n-octyl group) is bonded to a part of the plurality of chargeable groups 13 (carboxy groups) of the non-crosslinked polymer skeleton 11 via an amide bond.

[0045] <Metal Nanoparticles> The polymer of the present disclosure includes metal nanoparticles supported on the non-crosslinked polymer skeleton. Examples of the metal nanoparticles include nanoparticles formed from noble metal elements, specifically, silver nanoparticles, gold nanoparticles, platinum nanoparticles, palladium nanoparticles and rhodium nanoparticles. These nanoparticles are preferable because they are less likely to be oxidized in air or in a solvent. Among the metal nanoparticles, silver nanoparticles are preferable because they have high antibacterial and antiviral properties.

[0046] The supported form of the metal nanoparticles on the non-crosslinked polymer backbone is not particularly limited. The metal nanoparticles are bonded, for example, to a bonding group, preferably a charged group, contained in the main chain or side chain of the non-crosslinked polymer backbone. Examples of the bonding group include a carboxy group, a sulfo group, an amino group, a thiol group, and a thioether bond. Among these, anionic groups such as a carboxy group and a sulfo group are preferred, and a carboxy group is more preferred. The anionic group can strongly bond to the metal nanoparticles by being negatively charged (ionized) in water.

[0047] In the polymer of the present disclosure, the median diameter (D50) of the metal nanoparticles supported on the non-crosslinked polymer backbone is preferably less than 5 nm, more preferably 4 nm or less, still more preferably 3 nm or less, even more preferably 2 nm or less, and particularly preferably 1.5 nm or less. Metal nanoparticles with a D50 less than the upper limit value or below are considered not to cause the localized surface plasmon resonance described later. The lower limit of D50 is not particularly limited, but is, for example, 0.5 nm.

[0048] D50 is the median diameter (D50) indicating the 50% integrated value of the integrated distribution curve obtained by measuring the volume-based particle size distribution by the dynamic light scattering method (DLS). By using DLS, the particle size of the metal nanoparticles in the solvent can be measured in the state of being supported on the non-crosslinked polymer.

[0049] The content rate (loading rate) of the metal nanoparticles in the polymer of the present disclosure is preferably 10% by mass or more and 70% by mass or less, more preferably 15% by mass or more and 65% by mass or less. If the content rate is 10% by mass or more, the effects of the metal nanoparticles (for example, antibacterial and antiviral properties) are exhibited well. If the content rate is 70% by mass or less, aggregation of the metal nanoparticle-supported polymer in the solution is suppressed, and thus a composition or film excellent in transparency can be obtained.

[0050] The content rate of the metal nanoparticles is calculated using the following calculation formula.

[0051]

Equation

[0052] In the above formula, "the mass of the metal nanoparticle-supported polymer" represents the solid content mass when the solvent is removed from the obtained metal nanoparticle-supported polymer. On the other hand, "the mass of the non-crosslinked polymer" represents the mass of the non-crosslinked polymer introduced into the reaction system in the metal complex ion-supporting step described later.

[0053] <Absorbance> The metal nanoparticle-supported polymer of the present disclosure is characterized in that the absorbance in the range of a wavelength of 350 nm or more and 750 nm or less in an aqueous solution having a concentration of 0.01% by mass of the polymer is 0.100 or less. This is a significant feature as compared with the case of conventional metal nanoparticle-supported polymers, which could not achieve such a low absorbance. For example, by using the polymer of the present disclosure, a substantially colorless composition or film can be obtained while containing metal nanoparticles.

[0054] The above absorbance is measured by the following procedure. The metal nanoparticle-supported polymer and pure water are mixed to prepare an aqueous solution having a concentration of 0.01% by mass of the above polymer. This aqueous solution is placed in a cell with an optical path length of 1 cm, and the absorbance in the range of a wavelength of 300 nm or more and 800 nm or less is measured under the condition of a measurement temperature of 25 °C using an ultraviolet-visible spectrophotometer (for example, V-730 manufactured by JASCO Corporation). Pure water is used as the blank solution. The absorption spectrum is measured in a state where the aqueous solution substantially contains no impurities.

[0055] Regarding the reason why the absorbance in the above wavelength range is extremely low in the polymer of the present disclosure, the present inventors presume as follows. However, the following explanation is only a presumption and does not limit the polymer of the present disclosure in any way.

[0056] Metal nanoparticles with a particle size in the nanometer range are generally known to exhibit localized surface plasmon resonance (hereinafter also referred to as "localized SPR"). Localized SPR is a phenomenon in which free electrons in metal nanoparticles absorb incident light energy and cause collective vibration. When localized SPR occurs, a maximum absorption (hereinafter also referred to as "plasmon absorption") appears in the range of 350 nm or more and 750 nm or less. For example, in the case of silver nanoparticles, light in the range of 400 nm or more and 500 nm or less is strongly absorbed depending on the particle size, and in the case of gold nanoparticles, light in the range of 500 nm or more and 600 nm or less is strongly absorbed depending on the particle size.

[0057] The light absorption efficiency (molar extinction coefficient) due to localized SPR is known to be a thousand to a hundred thousand times higher than that of ordinary organic dyes. Therefore, even if only a small amount of metal nanoparticles is present in the system, the observer can recognize the color due to the metal nanoparticles. This has conventionally made it difficult to apply metal nanoparticles to applications that require transparency (for example, antibacterial and antiviral agents).

[0058] On the other hand, the polymer of the present disclosure exhibits extremely low absorbance. This is due to the fact that the metal nanoparticles contained in the polymer of the present disclosure do not cause localized SPR. The reason why the metal nanoparticles in the present disclosure do not cause localized SPR is related to the particle size of the metal nanoparticles. In the case of silver nanoparticles, it is considered that localized SPR occurs when the particle size is 5 nm or more and 100 nm or less, and localized SPR does not occur when the particle size is less than 5 nm.

[0059] For example, in the case of a polymer supporting silver nanoparticles, since the particle size of conventional silver nanoparticles is 5 nm or more, the color development due to the above-described localized SPR occurs. In the prior art, it was impossible to obtain ultra-fine silver nanoparticles with a particle size of less than 5 nm in a stable state.

[0060] However, in the present disclosure, by the manufacturing method described later, a polymer supporting silver nanoparticles with a particle size of less than 5 nm can be obtained. Therefore, in the present disclosure, silver nanoparticles that do not cause localized SPR can be obtained in a stable state. It is considered that such ultrafine silver nanoparticles can exist stably only when supported on a non-crosslinked polymer. In this polymer, almost no discoloration due to the influence of light or heat is shown. Note that the above matters are the same not only for silver nanoparticles but also for the above-described metal nanoparticles.

[0061] The presence or absence of the above localized SPR greatly affects the shape of the absorption spectrum of an aqueous solution with a concentration of 0.01% by mass of the metal nanoparticle-supported polymer. Since the metal nanoparticles in the polymer of the present disclosure do not cause localized SPR, the polymer of the present disclosure exhibits a very low absorbance. Thus, the presence or absence of localized SPR can be easily judged visually, and strictly speaking, it can be judged from the absorption spectrum of a 0.01% by mass aqueous solution of the metal nanoparticle-supported polymer. The above description is only an estimation and does not limit the polymer of the present disclosure in any way.

[0062] <Storage of Polymer Supported Metal Nanoparticles> The metal nanoparticle-supported polymer of the present disclosure is preferably stored in a state dissolved in a solvent. That is, the polymer of the present disclosure is preferably stored in a state of a solution containing the polymer. When the metal nanoparticle-supported polymer is dried and made into a powder, it may be difficult to redissolve it in a solvent.

[0063] In one embodiment, a metal nanoparticle-supported polymer in which a hydrophobic group is not bonded to the above chargeable group or the amount of introduced hydrophobic group is small can be stored in water for a long time. In one embodiment, a metal nanoparticle-supported polymer in which a hydrophobic group is bonded to the above chargeable group or the amount of introduced hydrophobic group is large can be stored in an organic solvent for a long time.

[0064] Examples of the solvent include water and organic solvents. Examples of the organic solvent include alcohol solvents such as methanol, ethanol, 2-propanol, and 1-butanol; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; glycol solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, and propylene glycol monomethyl ether acetate; ester solvents such as methyl acetate, ethyl acetate, and butyl acetate; hydrocarbon solvents such as n-hexane, cyclohexane, benzene, toluene, and xylene; halogenated hydrocarbon solvents such as methylene chloride and chloroform; ether solvents such as tetrahydrofuran; nitrogen-containing solvents such as acetonitrile and N,N-dimethylformamide; and sulfur-containing solvents such as dimethyl sulfoxide. The solvent may be one kind or a mixed solvent of two or more kinds.

[0065] [Method for Producing Polymer Supported Metal Nanoparticles]

[0066] The metal nanoparticle-supported polymer of the present disclosure can be produced, for example, by the following production method. In one embodiment, the production method of the metal nanoparticle-supported polymer of the present disclosure (1) A step of preparing a non-crosslinked polymer having a side chain containing a chargeable group, a metal salt, and a complexing agent (hereinafter also referred to as "step (1)" or "preparation step"), (2) A step of dissolving the non-crosslinked polymer, the metal salt, and the complexing agent in water to obtain a metal complex ion-supported polymer in which metal complex ions are supported on the non-crosslinked polymer (hereinafter also referred to as "step (2)" or "metal complex ion support step"), (3) A step of reducing the metal complex ions in the metal complex ion-supported polymer to form metal nanoparticles supported on the non-crosslinked polymer (hereinafter also referred to as "step (3)" or "metal nanoparticle formation step") (see Figure 2).

[0067] In one embodiment, the production method of the metal nanoparticle-supported polymer of the present disclosure (4) Step of bonding a hydrophobic group to the charged group of the non-crosslinked polymer (hereinafter also referred to as "step (4)" or "hydrophobization step") further includes (see Figure 2).

[0068] In one embodiment, the method for producing a metal nanoparticle-supported polymer of the present disclosure (5) Step of isolating the metal nanoparticle-supported polymer (hereinafter also referred to as "step (5)" or "polymer isolation step") further includes.

[0069] <Step (1) (Preparation Step)> Step (1) is a step of preparing a non-crosslinked polymer having a side chain containing a charged group, a metal salt, and a complexing agent. Since the details of the non-crosslinked polymer have been described above, the description is omitted here. The metal salt and the complexing agent will be described in the following step (2).

[0070] <Step (2) (Metal Complex Ion Loading Step)> Step (2) is a step of dissolving the non-crosslinked polymer, the metal salt, and the complexing agent in water to obtain a metal complex ion-supported polymer in which metal complex ions are supported on the non-crosslinked polymer.

[0071] When the metal salt and the complexing agent are dissolved in water, metal complex ions are usually formed. When the non-crosslinked polymer coexists in this system, the metal complex ions are supported on the non-crosslinked polymer. Figure 3 shows a schematic diagram of the step in which metal complex ions 31 are supported on the non-crosslinked polymer 11. By forming metal complex ions using a complexing agent, the reduction rate of metal ions can be appropriately controlled in step (3), and an increase in the particle size of metal nanoparticles can be suppressed.

[0072] The metal salt is not particularly limited as long as it dissolves in water and ionizes. As the metal salt, salts containing the above-mentioned noble metal elements are preferable, and examples include silver salts such as silver nitrate and silver sulfate, chloroauric acid, chloroplatinic acid, palladium chloride, and rhodium chloride. Among these, silver salts are preferable, and silver nitrate is more preferable.

[0073] A complexing agent means a compound capable of forming a complex with metal ions and is a ligand for metal ions. Examples of the complexing agent include compounds having a functional group capable of coordinating to metal ions. Examples of the functional group capable of coordinating to metal ions include monovalent functional groups such as amino group, hydroxy group, carboxy group and thiol group; and divalent functional groups such as ether bond and thioether bond (sulfide bond). Among these, from the viewpoint of suppressing the aggregation of the polymer in the solution well, amino group, hydroxy group, ether bond and thioether bond (sulfide bond) are preferable.

[0074] The number of functional groups capable of coordinating to metal ions in the complexing agent is preferably 2 or more, more preferably 2 or more and 6 or less, and still more preferably 2 or more and 4 or less. With such a number of functional groups, the complexing agent can coordinate well to metal ions.

[0075] The molecular weight of the complexing agent is preferably 400 or less, more preferably 300 or less, still more preferably 200 or less, and even more preferably 150 or less. With such a molecular weight, the complexing agent can coordinate well to metal ions and the obtained metal complex ion can be supported well on the non-crosslinked polymer.

[0076] Specific examples of the complexing agent include ethylenediamine, 2,2'-thiodiethanol, ethanolamine, diethanolamine, diglycolamine, disodium ethylenediaminetetraacetate (EDTA·2Na), disodium iminodiacetate and sodium citrate. Among these, from the viewpoint of suppressing the aggregation of the polymer in the solution well, ethylenediamine, 2,2'-thiodiethanol, ethanolamine, diethanolamine and diglycolamine are preferable.

[0077] For example, when polyacrylic acid is used as the non-crosslinked polymer, silver nitrate is used as the metal salt, and ethylenediamine, thiodiethanol, or ethanolamine is used as the complexing agent, an example of the state of the metal complex ions supported on the non-crosslinked polymer is shown below.

[0078]

Chemical formula

[0079] For example, it is considered that the above functional group in the complexing agent and the carboxylate ion in polyacrylic acid coordinate from both sides of the silver ion. That is, a silver complex ion composed of silver ions coordinated by the complexing agent is formed, and it is considered that the carboxylate ion in polyacrylic acid coordinates to the silver complex ion. At this time, if polyacrylic acid is loosened by the electrostatic repulsion of the carboxylate ion as described above, the silver complex ion is likely to approach the carboxylate ion in polyacrylic acid, so the loading amount of the silver complex ion increases.

[0080] Specifically, step (2) preferably includes a step of preparing an aqueous solution of a non-crosslinked polymer having a side chain containing a charged group, and a step of adding a metal salt and a complexing agent to the aqueous solution.

[0081] First, dissolve the non-crosslinked polymer in water. The concentration of the non-crosslinked polymer in the aqueous solution is preferably 0.1% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 5% by mass. When the concentration of the non-crosslinked polymer is below the upper limit value, the loading efficiency of the metal complex ions is good. When the concentration of the non-crosslinked polymer is above the lower limit value, the production efficiency is good.

[0082] From the viewpoint of promoting the dissolution of the non-crosslinked polymer in water, the aqueous solution may be heated as necessary. For example, the liquid temperature of the aqueous solution is preferably heated to 50°C or more and 90°C or less, more preferably 60°C or more and 85°C or less.

[0083] In order to charge the charged groups contained in the non-crosslinked polymer in water, an acid or a base may be added to the aqueous solution of the non-crosslinked polymer as necessary to adjust the pH. For example, when the charged group is a carboxy group, if the pH of the aqueous solution is adjusted to a range of 5 or more and 9 or less, the non-crosslinked polymer tends to be loosened by electrostatic repulsion, and the amount of metal complex ions supported increases. Further, by adjusting the pH, the reduction rate in step (3), and thus the formation rate of metal nanoparticles, can be adjusted. Examples of the pH adjuster include bases such as sodium hydroxide, potassium hydroxide, and sodium carbonate; and acids such as hydrochloric acid and nitric acid.

[0084] Next, a complexing agent and a metal salt are added to the aqueous solution of the non-crosslinked polymer. The final concentrations of the complexing agent and the metal salt in the aqueous solution are each independently preferably 1 mM or more and 1000 mM or less, more preferably 5 mM or more and 700 mM or less, and still more preferably 10 mM or more and 200 mM or less.

[0085] The addition amount of the complexing agent is preferably 1 to 100 times the molar amount of the addition amount of the metal salt, more preferably 1 to 50 times the molar amount, still more preferably 1 to 10 times the molar amount, and particularly preferably 3 to 5 times the molar amount. When the addition amount of the complexing agent is below the upper limit value, it is preferable that the amount of metal complex ions supported does not decrease. When the addition amount of the complexing agent is above the lower limit value, it is preferable that the solubility of the metal salt in water increases.

[0086] From the viewpoint of promoting the loading of metal complex ions onto the non-crosslinked polymer, the aqueous solution may be heated as necessary. For example, the liquid temperature of the aqueous solution is preferably heated to 50°C or more and 90°C or less, more preferably 60°C or more and 85°C or less. When heated, the loading of metal complex ions is usually completed within 10 minutes.

[0087] The content rate (loading rate) of the metal complex ions in the metal complex ion-supported polymer is preferably 10% by mass or more and 70% by mass or less, more preferably 15% by mass or more and 65% by mass or less. If the content rate is 10% by mass or more, a sufficient amount of metal nanoparticles can be formed in subsequent steps. If the content rate is 70% by mass or less, aggregation of the metal complex ion-supported polymer in the solution is suppressed, and a composition or film with excellent transparency can be obtained.

[0088] The content rate of the metal complex ions is calculated using the following formula.

[0089]

Equation

[0090] In the above formula, "the mass of the metal complex ion-supported polymer" represents the solid content mass when the solvent is removed from the obtained metal complex ion-supported polymer. On the other hand, "the mass of the non-crosslinked polymer" represents the mass of the non-crosslinked polymer introduced into the reaction system in the metal complex ion loading step.

[0091] The aqueous solution of the metal complex ion-supported polymer obtained in step (2) may be subjected to a purification step. By the purification step, unreacted substances and impurities can be removed. Examples of the purification method include dialysis and gel filtration chromatography.

[0092] <Step (3) (Metal Nanoparticle Formation Step)> Step (3) is a step of reducing the metal complex ions in the metal complex ion-supported polymer to form metal nanoparticles supported on the non-crosslinked polymer. By this step, a metal nanoparticle-supported polymer in which metal nanoparticles are supported on the non-crosslinked polymer skeleton is obtained. In step (3), by reducing the metal complex ions while they are supported on the non-crosslinked polymer, metal nanoparticles with a small particle size can be formed. Fig. 3 shows a schematic diagram of the step in which the metal complex ions 31 supported on the non-crosslinked polymer 11 are reduced to metal nanoparticles 12.

[0093] The metal complex ion may be reduced using a reducing agent, may be reduced by physical actions such as ultrasonic waves, light irradiation, and γ-ray irradiation without using a reducing agent, or may be reduced by using a reducing agent and a physical action in combination.

[0094] As the reducing agent, a known compound having reducing properties can be used. Examples of the reducing agent include glucose, diethylenetriamine, triethylenetetramine, citric acid, ascorbic acid, sodium borohydride, hydrazine, ethanol, polyol, formaldehyde, tannic acid, and diborane.

[0095] The addition amount of the reducing agent is preferably 0.1 mol or more and 5 mol or less, more preferably 0.5 mol or more and 3 mol or less, and still more preferably 0.8 mol or more and 1.5 mol or less with respect to 1 mol of the metal salt added in step (2). It is particularly preferable to add the reducing agent in an equimolar amount with respect to the metal salt added in step (2). If the addition amount of the reducing agent is within the above range, metal ions can be reduced to form metal nanoparticles, and an increase in their particle size can be suppressed.

[0096] The reaction temperature and reaction time in step (3) are preferably set according to the reducing agent used and the above-described physical actions. In one embodiment, the reaction temperature in step (3) is, for example, 5°C or higher and 90°C or lower, preferably 10°C or higher and 85°C or lower. When reduction is carried out under mild conditions, an increase in the particle size of the metal nanoparticles can be suppressed. For example, by appropriately adjusting the reaction temperature and reaction time during reduction according to the reducing power of the reducing agent, the particle size of the formed metal nanoparticles can be controlled.

[0097] The aqueous solution of the polymer supporting the metal nanoparticles obtained in step (3) may be subjected to a purification step. Unreacted substances and impurities can be removed by the purification step. Examples of the purification method include dialysis and gel filtration chromatography.

[0098] <Step (4) (Hydrophobization Step)> The hydrophobization process is a process of hydrophobizing the charged groups contained in the metal nanoparticle-supported polymer. In one embodiment, a hydrophobic group is introduced into the charged group contained in the metal nanoparticle-supported polymer. For example, a hydrophobic group is introduced by esterifying or amidating the above-mentioned charged group.

[0099] Note that the polymer obtained in the hydrophobization process is also included in the metal nanoparticle-supported polymer. However, when the polymers before and after the hydrophobization process are described by particularly distinguishing them, the polymer obtained in the hydrophobization process is described as a "metal nanoparticle-supported hydrophobized polymer". Specific examples of the hydrophobic group are as described above.

[0100] For example, an amide bond is formed by a condensation reaction between a carboxy group in a non-crosslinked polymer backbone supporting metal nanoparticles and an amine having a hydrophobic group, and the hydrophobic group is introduced into the above polymer backbone. FIG. 4 shows a schematic diagram of a process of introducing an n-octyl group into the carboxy group of polyacrylic acid supporting metal nanoparticles (converting the carboxy group into an n-octylaminocarbonyl group).

[0101] Examples of the amine having a hydrophobic group include amines having an aliphatic hydrocarbon group such as alkylamines such as n-butylamine, t-butylamine, n-hexylamine, 2-ethylhexylamine, n-octylamine, decylamine, hexadecylamine and octadecylamine; alkenylamines such as oleylamine; amines having an alicyclic hydrocarbon group such as cycloalkylamines such as cyclohexylamine; and amines having an aromatic ring-containing hydrocarbon group such as aralkylamines such as benzylamine.

[0102] In order to allow the above condensation reaction to proceed under mild conditions, it is preferable to use a condensing agent. Examples of the condensing agent include carbodiimide-based condensing agents such as 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl), dicyclohexylcarbodiimide, and diisopropylcarbodiimide; triazine-based condensing agents such as 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM); and carbonate ester-based condensing agents such as carbonyldiimidazole. Among these, EDC·HCl and DMT-MM, which can be used in water, are preferable.

[0103] After converting the carboxy group in the non-crosslinked polymer backbone into an active ester group, an amide bond may be formed. In that case, it is preferable to use N-hydroxysuccinimide (NHS), 1-hydroxybenzotriazole (HOBT), etc. in combination with the above carbodiimide-based condensing agent.

[0104] For example, an ester bond is formed by a condensation reaction between a carboxy group in a non-crosslinked polymer backbone supporting metal nanoparticles and an alcohol having a hydrophobic group, and the hydrophobic group is introduced into the above polymer backbone. For example, an amide bond is formed by a condensation reaction between an amino group in a non-crosslinked polymer backbone supporting metal nanoparticles and a carboxylic acid having a hydrophobic group, and the hydrophobic group is introduced into the above polymer backbone.

[0105] The above condensation reaction is usually carried out in water. When the miscibility of an amine, alcohol, or carboxylic acid having a hydrophobic group with water is not high, it is preferable to add a necessary amount of alcohol to water. That is, it is preferable to use a mixed solvent of water and alcohol as the reaction solvent. Examples of the alcohol include methanol and ethanol. The mixing ratio of water and alcohol is set so that an alkylamine or the like to be used can be freely miscible with the solvent. For example, octylamine is miscible well with a mixed solvent of equal volumes of water and methanol.

[0106] In the above condensation reaction, the concentration of the metal nanoparticle-supported polymer in the aqueous solution is preferably 0.1% by mass or more and 2% by mass or less, more preferably 0.5% by mass or more and 1% by mass or less. When the concentration is below the upper limit value, the condensation reaction proceeds well. When the concentration is above the lower limit value, the production efficiency is improved.

[0107] In the hydrophobization step, the metal nanoparticle-supported polymer is hydrophobized, and usually, an emulsion (aqueous dispersion) of the metal nanoparticle-supported hydrophobized polymer is formed. That is, the emulsion of the metal nanoparticle-supported polymer is formed simultaneously with the introduction of a hydrophobic group into the non-crosslinked polymer backbone. When a hydrophobic group is introduced into the metal nanoparticle-supported polymer, the solubility of the polymer in an aqueous solvent (for example, water and a mixed solvent of water and alcohol) decreases, and part or all of the metal nanoparticle-supported polymer cannot be dissolved in the aqueous solvent and is dispersed in the aqueous solvent as fine droplets. In this way, an O / W type emulsion is formed.

[0108] Hereinafter, an example of hydrophobization using EDC·HCl, NHS, and alkylamine will be described. EDC·HCl and NHS are added to an aqueous solution of the metal nanoparticle-supported polymer. The final concentrations of these are preferably 1 mM or more and 100 mM or less, independently. The reaction temperature is preferably 20°C or more and 60°C or less, and the reaction time is preferably 1 minute or more and 30 minutes or less. Thereby, when a non-crosslinked polymer having a carboxy group is used, the carboxy group in the non-crosslinked polymer backbone constituting the metal nanoparticle-supported polymer is converted into an active ester group.

[0109] Next, alkylamine is added to the above aqueous solution. The final concentration of the alkylamine is preferably 10 mM or more and 300 mM or less, more preferably 10 mM or more and 100 mM or less. The reaction temperature is preferably 20°C or more and 50°C or less, and the reaction time is preferably 1 minute or more and 30 minutes or less. Thereby, the active ester group in the non-crosslinked polymer backbone constituting the metal nanoparticle-supported polymer reacts with the alkylamine to form an amide bond.

[0110] <Step (5) (Polymer Isolation Step)> The polymer isolation step is a step of isolating the metal nanoparticle-supported polymer. The metal nanoparticle-supported polymer (metal nanoparticle-supported hydrophobized polymer) in the emulsion is recovered, for example, by a known method. For example, by allowing the emulsion to stand, it can be separated into two layers: an upper solvent layer and a lower metal nanoparticle-supported polymer layer. To enhance the separation efficiency, centrifugation or electric field separation may be utilized. For example, after removing the upper solvent, it is preferable to dissolve the metal nanoparticle-supported polymer in the lower layer in a suitable organic solvent and recover it. Specific examples of the organic solvent are as described above.

[0111] In one embodiment, the isolation of the polymer is carried out by the following procedure. Transfer the above emulsion to a centrifuge tube and perform centrifugation using a centrifuge. The centrifugal acceleration is preferably 1,000×g or more and 10,000×g or less, and the centrifugation time is preferably 1 minute or more and 30 minutes or less. Next, remove the supernatant, and dissolve the metal nanoparticle-supported polymer remaining at the bottom of the centrifuge tube in an organic solvent such as alcohol. If necessary, perform ultrasonic treatment during the dissolution process.

[0112] [Composition] The composition of the present disclosure contains one or more of the metal nanoparticle-supported polymers of the present disclosure. In one embodiment, the composition of the present disclosure has antibacterial and antiviral properties and is preferably used for at least one of antibacterial and antiviral applications.

[0113] The content ratio of the polymer of the present disclosure in the composition of the present disclosure can be arbitrarily selected according to the use of the composition. In one embodiment, it is 0.01% by mass or more and 70% by mass or less, preferably 0.1% by mass or more and 50% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less.

[0114] In one embodiment, the composition of the present disclosure contains at least one selected from water and organic solvents. For example, the polymer of the present disclosure is dissolved in at least one selected from water and organic solvents. Examples of the organic solvent include the specific examples described above.

[0115] The content ratio of the solvent in the composition of the present disclosure can be arbitrarily selected according to the use of the composition. In one embodiment, it is 30% by mass or more and 99.5% by mass or less, preferably 50% by mass or more and 99% by mass or less, more preferably 60% by mass or more and 98% by mass or less.

[0116] For example, the composition of the present disclosure can be obtained by dissolving the metal nanoparticle-supported polymer of the present disclosure in at least one solvent selected from water and organic solvents. As a method for dissolving the polymer of the present disclosure in a solvent, for example, a method using a magnetic stirrer, a motor with stirring blades, a homogenizer or an ultrasonic cleaner can be mentioned. In one embodiment, the composition of the present disclosure is provided in forms such as liquid, gel and spray.

[0117] In one embodiment, the composition of the present disclosure contains one or more resins other than the polymer of the present disclosure. For example, the polymer of the present disclosure can be well mixed with the above resins. Since the polymer of the present disclosure is excellent in dispersibility in the resin, when the resin is excellent in transparency in one embodiment, the transparency of the resin can be maintained.

[0118] Examples of the resin include polyolefins such as polyethylene, polypropylene and cyclic polyolefin; polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; styrene resins such as acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer and polystyrene; polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacrylonitrile, polyamide, polyimide, polyamideimide, (meth)acrylic resin, polycarbonate, polyaryl phthalate, polysulfone, polyethersulfone, polyphenylene sulfide, polyurethane, acetal resin, cellulose resin, fluororesin, phenol resin, melamine resin, epoxy resin, unsaturated polyester resin and silicone resin.

[0119] The polymer of the present disclosure can be used in an amount of 0.1 part by mass or more and 50 parts by mass or less, preferably 0.5 part by mass or more and 40 parts by mass or less, more preferably 1 part by mass or more and 30 parts by mass or less, based on 100 parts by mass of the above resin.

[0120] The polymer of the present disclosure and the above resin can be mixed using a known mixing device such as a Henschel mixer, a V-type blender, a tumbler, rolls, and a kneader.

[0121] In one embodiment, the composition of the present disclosure contains one or more active energy ray curable resin components. For example, the polymer of the present disclosure can be well mixed with the active energy ray curable resin component. Since the polymer of the present disclosure has excellent dispersibility in the active energy ray curable resin component, in one embodiment, the transparency of the cured product of the active energy ray curable resin component can be maintained.

[0122] The active energy ray curable resin component is a resin component that cures upon irradiation with active energy rays. The resin component may be any of a monomer, an oligomer, and a polymer. Examples of the active energy rays include electromagnetic waves such as ultraviolet rays (UV), X-rays, and γ-rays; and charged particle beams such as electron beams (EB), α-rays, and ion beams.

[0123] As the active energy ray curable resin component, a photocurable resin component is preferable, and a (meth)acrylic photocurable resin component is more preferable. Examples of the (meth)acrylic photocurable resin component include polyfunctional (meth)acrylates [for example, (meth)acrylates having 2 or more and 8 or less polymerizable groups such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc.], epoxy (meth)acrylates [polyfunctional epoxy (meth)acrylates having 2 or more (meth)acryloyl groups], polyester (meth)acrylates [polyfunctional polyester (meth)acrylates having 2 or more (meth)acryloyl groups], urethane (meth)acrylates [polyfunctional urethane (meth)acrylates having 2 or more (meth)acryloyl groups], silicone (meth)acrylates [polyfunctional silicone (meth)acrylates having 2 or more (meth)acryloyl groups], and (meth)acrylic polymers having a polymerizable group.

[0124] The (meth)acrylic polymer having a polymerizable group may be a polymer in which a polymerizable unsaturated group is introduced into a part of the carboxy groups of the (meth)acrylic polymer. For example, it may be a (meth)acrylic polymer in which the epoxy group of an epoxy group-containing (meth)acrylate is reacted with a part of the carboxy groups of a (meth)acrylic acid-(meth)acrylate copolymer to introduce a polymerizable group (photopolymerizable unsaturated group) into the side chain.

[0125] In one embodiment, the polymer of the present disclosure can be used in an amount of 0.1 part by mass or more and 50 parts by mass or less, preferably 0.5 part by mass or more and 40 parts by mass or less, more preferably 1 part by mass or more and 30 parts by mass or less, based on 100 parts by mass of the active energy ray curable resin component.

[0126] When the composition contains a photocurable resin component, the composition preferably contains one or more photopolymerization initiators capable of initiating a curing reaction by light irradiation. Examples of the photopolymerization initiator include alkylphenone compounds, acetophenone compounds, benzoin compounds, acylphosphine oxide compounds, benzophenone compounds, thioxanthone compounds, and aminobenzophenone compounds. The content of the photopolymerization initiator is preferably 0.1 part by mass or more and 15 parts by mass or less, more preferably 0.5 part by mass or more and 10 parts by mass or less, based on 100 parts by mass of the photocurable resin component.

[0127] The polymer of the present disclosure is excellent in miscibility with a resin and a photoactive energy ray-curable resin component and also excellent in dispersibility, so that metal nanoparticles contained in the polymer of the present disclosure can be present at a sufficient density on the surface of the film formed from the composition of the present disclosure. Thereby, in one embodiment, high immediate antibacterial and antiviral properties can be obtained.

[0128] The composition of the present disclosure may contain one or more other antibacterial and antiviral components, such as sodium hypochlorite, hypochlorous acid water, and quaternary ammonium salts, if necessary. The composition of the present disclosure may contain at least one selected from the group consisting of a dispersion stabilizer, a humectant, a thickener, a pH adjuster, and a surfactant, if necessary.

[0129] Using the composition of the present disclosure, various molded articles such as pellets, sheets, films, plates, containers, and pipes can be formed. The composition of the present disclosure may be applied to the surface of a substrate, such as a paint and a coating agent.

[0130] [Article] The article of the present disclosure includes the composition of the present disclosure. In one embodiment, the component formed from the composition of the present disclosure has antibacterial and antiviral properties. Therefore, the article of the present disclosure is preferably used for at least one of antibacterial and antiviral applications.

[0131] The articles of the present disclosure are not particularly limited as long as they contain the compositions of the present disclosure. The above articles are formed from the compositions of the present disclosure or include components (e.g., surface layers, members, or parts) formed from the compositions of the present disclosure. In one embodiment, the article of the present disclosure includes a layer formed from the composition of the present disclosure, and the layer constitutes at least a part of the surface layer of the article of the present disclosure. Since the articles of the present disclosure are excellent in antibacterial and antiviral properties in one embodiment, they can be widely used, for example, as articles that people touch with their hands.

[0132] In one embodiment, the thickness of the layer formed from the composition of the present disclosure is 0.05 μm or more and 200 μm or less, preferably 0.1 μm or more and 10 μm or less, more preferably 0.15 μm or more and 5 μm or less.

[0133] In the present disclosure, the antibacterial property of the article is evaluated in accordance with ISO 22196 (JIS Z2801), and the antiviral property of the article is evaluated in accordance with ISO 21702.

[0134] Examples of the above articles include film products for protecting touch panels, face shields, handrails, buttons, switches, and windows; textile products such as socks, underwear, towels, curtains, and carpets; building materials such as floor materials, wallpapers, tiles, and paints; kitchen supplies such as sponges, cutting boards, film packaging materials, brushes, and lunch boxes; bath and toilet supplies such as bath mats, brushes with toilet cases, and bottles; daily necessities such as toothbrushes, shoe insoles, masks, and antibacterial sprays; toys such as stuffed animals and building blocks; household appliances such as washing machines, vacuum cleaners, and refrigerators; and automotive parts such as steering wheels, shift knobs, air cleaners, and interior materials.

[0135] The present disclosure relates to, for example, the following [1] to

[17] . [1] A metal nanoparticle-supported polymer comprising a non-crosslinked organic polymer backbone having a side chain containing a charged group and metal nanoparticles supported on the non-crosslinked organic polymer backbone, wherein the absorbance in the range of wavelengths from 350 nm to 750 nm in an aqueous solution with a concentration of 0.01% by mass of the metal nanoparticle-supported polymer is 0.100 or less. [2] The metal nanoparticle-supported polymer according to [1] above, wherein the metal nanoparticles are bonded to the charged group. [3] The metal nanoparticle-supported polymer according to [1] or [2] above, wherein the charged group is a carboxy group. [4] The metal nanoparticle-supported polymer according to any one of [1] to [3] above, wherein a hydrophobic group is bonded to a part of the plurality of charged groups of the non-crosslinked organic polymer backbone. [5] The metal nanoparticle-supported polymer according to [4] above, wherein the hydrophobic group is a hydrocarbon group having 4 to 18 carbon atoms. [6] The metal nanoparticle-supported polymer according to any one of [1] to [5] above, wherein the metal nanoparticles are silver nanoparticles. [7] The metal nanoparticle-supported polymer according to any one of [1] to [6] above, wherein the content rate of the metal nanoparticles is 10% by mass or more and 70% by mass or less. [8] A composition containing the metal nanoparticle-supported polymer according to any one of [1] to [7] above. [9] The composition according to [8] above, which has antibacterial and / or antiviral properties.

[10] An article containing the composition according to [8] or [9] above.

[11] A method for producing a metal nanoparticle-supported polymer, comprising: (1) a step of preparing a non-crosslinked organic polymer having a side chain containing a charged group, a metal salt, and a complexing agent; (2) a step of dissolving the non-crosslinked organic polymer, the metal salt, and the complexing agent in water to obtain a metal complex ion-supported polymer in which metal complex ions are supported on the non-crosslinked organic polymer; and (3) a step of reducing the metal complex ions in the metal complex ion-supported polymer to form metal nanoparticles supported on the non-crosslinked organic polymer, wherein the absorbance in the range of wavelengths from 350 nm to 750 nm in an aqueous solution with a concentration of 0.01% by mass of the obtained metal nanoparticle-supported polymer is 0.100 or less.

[12] The method for producing a metal nanoparticle-supported polymer according to

[11] above, further comprising a step of bonding a hydrophobic group to a charged group of the non-crosslinked organic polymer.

[13] The method for producing a metal nanoparticle-supported polymer according to

[12] above, wherein the hydrophobic group is a hydrocarbon group having 4 to 18 carbon atoms.

[14] In step (4), an emulsion of the hydrophobized metal nanoparticle-supported polymer is formed, and the production method further comprises (5) a step of isolating the hydrophobized metal nanoparticle-supported polymer from the emulsion. The method for producing a metal nanoparticle-supported polymer according to

[12] or

[13] above.

[15] The method for producing a metal nanoparticle-supported polymer according to any one of

[11] to

[14] above, wherein the charged group is a carboxy group.

[16] The method for producing a metal nanoparticle-supported polymer according to any one of

[11] to

[15] above, wherein the metal salt is a silver salt.

[17] The method for producing a metal nanoparticle-supported polymer according to any one of

[11] to

[16] above, wherein the complexing agent is a compound having a molecular weight of 400 or less and having at least one functional group selected from an amino group, a hydroxy group, a carboxy group, a thiol group, an ether bond, and a sulfide bond.

Examples

[0136] Hereinafter, the polymers and the like of the present disclosure will be described using specific examples. [Antibacterial Test] The antibacterial property of the metal nanoparticle-supported polymer aqueous solution was evaluated according to the following procedure.

[0137] The polymer (such as a silver nanoparticle-supported polymer) obtained in the example or comparative example was added to pure water to obtain 10 mL of an aqueous solution (specimen) having a polymer concentration of 0.01% by mass. Escherichia coli (NBRC 3972) used in the test was cultured in a liquid medium at 35 °C for 24 hours for enrichment culture. After the culture, the concentration of Escherichia coli was adjusted to 10 using sterilized normal broth medium (1 / 500 NB medium). 8Adjusted to cfu / mL (cfu: colony forming unit). 0.1 mL of this bacterial solution was inoculated into 10 mL of the above specimen containing the above polymer and left at 25°C for 1 hour. Then, a 10-fold dilution series of the specimen was prepared using sterilized phosphate buffered saline (PBS). 1 mL was taken from each dilution series and mixed with SCDLP agar medium. After culturing this at 30°C for 48 hours, the grown colonies were counted and converted to the viable cell count. As a negative control, PBS not containing the above polymer was similarly tested. Finally, the antibacterial activity value was calculated using the following formula. When the antibacterial activity value was 2.0 or more, it was determined to be effective.

[0138]

Number

[0139] [Measurement of Absorption Spectrum and Absorbance] The polymer obtained in the example or comparative example and pure water were mixed to prepare an aqueous solution with a concentration of 0.01% by mass of the polymer. This aqueous solution was placed in a cell with an optical path length of 1 cm, and using an ultraviolet-visible spectrophotometer (V-730 manufactured by JASCO Corporation), the absorbance in the wavelength range of 300 nm or more and 800 nm or less was measured under the condition of a measurement temperature of 25°C. Pure water was used as the blank solution. The absorption spectrum was measured in a state where the aqueous solution substantially contained no impurities.

[0140] [Measurement of Particle Size of Metal Nanoparticles] Measurement was performed by the dynamic light scattering method (DLS) as follows. The polymer obtained in the example or comparative example and pure water were mixed to prepare a plurality of diluted aqueous solutions of the polymer. The aqueous solution concentration was selected to be within the specified range of a particle size distribution meter (NanoTrack UPA-UT manufactured by Nikkiso Co., Ltd.) used for particle size measurement, and the particle size distribution was measured under the conditions of a solvent refractive index of 1.333, a non-spherical particle shape, and a measurement temperature of 20°C.

[0141] [Silver Nanoparticle Content] The content rate of silver nanoparticles was calculated according to the above-described formula.

[0142] [Example 1] 0.6 g of polyacrylic acid (weight average molecular weight 25,000, FUJIFILM Wako Pure Chemical Industries, Ltd.) was dissolved in 30 mL of water. To this, 1 mL of ethylenediamine and 0.85 g of silver nitrate were added, and the mixture was stirred at 70 - 80 °C for 5 minutes. Next, 0.54 mL of diethylenetriamine was added, and the mixture was further stirred at room temperature for 30 minutes. Finally, the obtained polymer aqueous solution was sealed in a dialysis tube and dialysis was performed in pure water. The silver nanoparticle content of the obtained polymer supporting silver nanoparticles was 56.4 mass%.

[0143] [Example 2] 0.6 g of polyacrylic acid (weight average molecular weight 25,000, FUJIFILM Wako Pure Chemical Industries, Ltd.) was dissolved in 30 mL of water. To this, 1 mL of ethylenediamine and 0.425 g of silver nitrate were added, and the mixture was stirred at 70 - 80 °C for 5 minutes. Next, 0.27 mL of diethylenetriamine was added, and the mixture was further stirred at 70 - 80 °C for 5 minutes. Finally, the obtained polymer aqueous solution was sealed in a dialysis tube and dialysis was performed.

[0144] [Examples 3 - 5] The procedure was the same as in Example 2 except that the amounts of silver nitrate and diethylenetriamine used were changed as described in Table 1.

[0145] [Example 6] 0.6 g of polyacrylic acid (weight average molecular weight 25,000, FUJIFILM Wako Pure Chemical Industries, Ltd.) was dissolved in 30 mL of water. To this, 5 mL of 1 M NaOH aqueous solution, 2 mL of thiodiethanol, and 0.85 g of silver nitrate were sequentially added, and the mixture was stirred at 70 - 80 °C for 5 minutes. Next, 5 mL of 1 M D - glucose aqueous solution was added, and the mixture was further stirred at 70 - 80 °C for 15 minutes. Finally, the obtained polymer aqueous solution was sealed in a dialysis tube and dialysis was performed in pure water. When the particle size (D50) of the silver nanoparticles was measured using DLS, it was 1 nm.

[0146] [Example 7] 0.6 g of sodium carboxymethyl cellulose (FUJIFILM Wako Pure Chemical Corporation, hereinafter also referred to as "CMC·Na") was dissolved in 30 mL of water. 2 mL of thiodiethanol and 0.85 g of silver nitrate were added thereto, and the mixture was stirred at 70 - 80 °C for 5 minutes. Subsequently, 5 mL of 1M D-glucose aqueous solution was added, and the mixture was further stirred at 70 - 80 °C for 30 minutes. Finally, the obtained polymer aqueous solution was sealed in a dialysis tube and dialysis was carried out in pure water.

[0147] [Comparative Example 1] The procedure was carried out in the same manner as in Example 1 except that silver nitrate was not added.

[0148] [Comparative Example 2] 0.6 g of polyacrylic acid (weight average molecular weight 25,000, FUJIFILM Wako Pure Chemical Corporation) was dissolved in 30 mL of water. 1 mL of ethylenediamine and 0.85 g of silver nitrate were added thereto, and the mixture was stirred at 70 - 80 °C for 5 minutes. Subsequently, 5 mL of 1M D-glucose aqueous solution was added, and the mixture was further stirred at 70 - 80 °C for 30 minutes. Finally, the obtained polymer aqueous solution was sealed in a dialysis tube and dialysis was carried out in pure water.

[0149] [Comparative Example 3] 0.6 g of bovine bone gelatin (FUJIFILM Wako Pure Chemical Corporation) was dissolved in 30 mL of water. 2 mL of thiodiethanol and 0.21 g of silver nitrate were added thereto, and the mixture was stirred at 70 - 80 °C for 5 minutes. Subsequently, 1.25 mL of 1M D-glucose aqueous solution and 5 mL of 1M NaOH aqueous solution were added, and the mixture was further stirred at 70 - 80 °C for 15 minutes. Finally, the obtained polymer aqueous solution was sealed in a dialysis tube and dialysis was carried out in pure water.

[0150] [Comparative Example 4] The procedure was carried out in the same manner as in Comparative Example 3 except that the amount of silver nitrate added was changed to 0.05 g and the amount of 1M D-glucose aqueous solution added was changed to 0.31 mL.

[0151] [Results] When the absorption spectrum of the aqueous solution of the polymer obtained in the example was measured, plasmon absorption by silver nanoparticles was not observed (Figure 5), and moreover, this aqueous solution exhibited excellent antibacterial properties (Table 1).

[0152] When the absorption spectrum of the aqueous solution of the polymer obtained in Comparative Example 1 was measured, since silver nitrate was not added, silver nanoparticles were not present, and thus plasmon absorption was not observed (Figure 6). When an antibacterial test was conducted on this aqueous solution, antibacterial properties were not recognized (Table 2). Although the aqueous solutions of the polymers obtained in Comparative Examples 2 to 4 exhibited antibacterial properties, plasmon absorption by silver nanoparticles was observed.

[0153]

Table 1

[0154]

Table 2

[0155] In Example 1, diethylenetriamine having a strong reducing power was used and reacted at 30 °C or lower for 30 minutes. On the other hand, in Comparative Example 2, glucose having a weak reducing power was used and reacted at 70 °C or higher for 30 minutes. Thus, by appropriately controlling the reaction temperature and reaction time during reduction according to the reducing power of the reducing agent, silver nanoparticles without observable plasmon absorption could be formed.

[0156] In Example 6, a pH adjuster was added to the polyacrylic acid aqueous solution before adding silver nitrate, and glucose having a weak reducing power was used and reacted at 70 °C or higher for 15 minutes. On the other hand, in Comparative Example 2, glucose having a weak reducing power was used and reacted at 70 °C or higher for 30 minutes. Thus, even when using a reducing agent with a weak reducing power, by appropriately controlling the reaction temperature, reaction time, and pH during reduction, silver nanoparticles without observable plasmon absorption could be formed.

[0157] As described above, by appropriately adjusting the reaction temperature, reaction time, pH, etc. during reduction according to the reducing power of the reducing agent, silver nanoparticles that do not exhibit plasmon absorption can be formed.

[0158] In Comparative Example 3, it is considered that the amount of silver complex ions supported on bovine bone gelatin is less than that on polyacrylic acid. When the amount of silver complex ions supported is small, silver nanoparticles tend to be formed in a free state in the solution. The silver nanoparticles thus formed are considered to rapidly aggregate and reach a size of 5 nm or more. Therefore, it is also preferable to reduce the silver complex ions in a state where most of the silver complex ions are supported (fixed) on the polymer from the viewpoint of suppressing the above aggregation.

[0159] [Example 8] The silver nanoparticle-supported polymer obtained in Example 6 was hydrophobized according to the following procedure. First, 10 mL of pure water and 20 mL of methanol were added to 10 mL of an aqueous solution of silver nanoparticle-supported polymer (3.1% by mass). 2 mL of an aqueous solution of EDC·HCl / NHS (each 0.1 M) was added thereto and left for 10 minutes. 1.5 mL of n-octylamine was added thereto and left for 3 minutes. Thereby, an emulsion of the hydrophobized polymer supporting silver nanoparticles was obtained. After centrifuging this emulsion, the supernatant was removed, and the obtained solid content was dissolved in 10 mL of methanol. The solid content concentration of the obtained hydrophobized polymer supporting silver nanoparticles was 2.0% by mass.

[0160] [Example 9] A coating agent was prepared using a methanol solution of the hydrophobized polymer supporting silver nanoparticles obtained in Example 8, and the polyethylene terephthalate (PET) film was coated as follows using the coating agent.

[0161] First, a coating agent having the following composition was prepared. · Solvent: Methyl isobutyl ketone 5.046 g · Antibacterial component: 2.0% by mass methanol solution of the hydrophobized polymer supporting silver nanoparticles 0.789 mL ·UV curable resin component: PET-30 (Nippon Kayaku) 0.157 g ·Polymerization initiator: Omnirad184 (BASF) 0.006 g

[0162] The above coating agent was applied to a PET film (Cosmo Shine (registered trademark) A4100, Toyobo) and dried, and then irradiated with ultraviolet rays. As a result, a cured film with a thickness of about 200 nm containing a silver nanoparticle-supported hydrophobized polymer was formed on the surface of the PET film.

[0163] The antibacterial property of the cured film obtained as described above was evaluated according to ISO 22196 (JIS Z2801). As a result, the antibacterial activity value was 7.4, and excellent antibacterial property was recognized. The negative control was the above PET film not coated with the above coating agent.

Explanation of reference numerals

[0164] 10 ··· Metal nanoparticle-supported polymer 11 ··· Non-crosslinked polymer (skeleton) 12 ··· Metal nanoparticles 13 ··· Charged group 14 ··· Hydrophobic group 31 ··· Metal complex ion

Claims

1. (1) A step of preparing a non-crosslinked organic polymer having a side chain containing a charged group, a metal salt, and a complexing agent; (2) A step of dissolving the non-crosslinked organic polymer, the metal salt, and the complexing agent in water to obtain a metal complex ion-supported polymer in which metal complex ions are supported on the non-crosslinked organic polymer; (3) A step of reducing the metal complex ions in the metal complex ion-supported polymer to form metal nanoparticles supported on the non-crosslinked organic polymer; (4) A step of bonding a hydrophobic group to the charged group of the non-crosslinked organic polymer and the absorbance in the range of 350 nm or more and 750 nm or less in an aqueous solution having a concentration of 0.01% by mass of the obtained metal nanoparticle-supported polymer is 0.100 or less; the hydrophobic group is a hydrocarbon group having 4 to 18 carbon atoms, A method for producing a metal nanoparticle-supported polymer.

2. In the step (4), an emulsion of the hydrophobized metal nanoparticle-supported polymer is formed, and the production method further includes (5) a step of isolating the hydrophobized metal nanoparticle-supported polymer from the emulsion. The method for producing a metal nanoparticle-supported polymer according to Claim 1.

3. The method for producing a metal nanoparticle-supported polymer according to Claim 1 or 2, wherein the charged group is a carboxy group.

4. The method for producing a metal nanoparticle-supported polymer according to any one of Claims 1 to 3, wherein the metal salt is a silver salt.

5. The method for producing a metal nanoparticle-supported polymer according to any one of Claims 1 to 4, wherein the complexing agent is a compound having a molecular weight of 400 or less and having at least one functional group selected from an amino group, a hydroxy group, a carboxy group, a thiol group, an ether bond, and a thioether bond.

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