WO2016104359A1 - Method for producing silver nanowires, silver nanowires obtained by said method, and ink containing said silver nanowires - Google Patents

Method for producing silver nanowires, silver nanowires obtained by said method, and ink containing said silver nanowires Download PDF

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WO2016104359A1
WO2016104359A1 PCT/JP2015/085481 JP2015085481W WO2016104359A1 WO 2016104359 A1 WO2016104359 A1 WO 2016104359A1 JP 2015085481 W JP2015085481 W JP 2015085481W WO 2016104359 A1 WO2016104359 A1 WO 2016104359A1
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silver
silver nanowires
producing
nanowires
compound
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PCT/JP2015/085481
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French (fr)
Japanese (ja)
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内田　博
真尚 原
菅原　篤
守 橘川
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昭和電工株式会社
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Priority to CN201580063555.3A priority Critical patent/CN107000065B/en
Priority to KR1020177012753A priority patent/KR101990346B1/en
Priority to JP2016566193A priority patent/JP6636949B2/en
Publication of WO2016104359A1 publication Critical patent/WO2016104359A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
    • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
    • B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/07—Metallic powder characterised by particles having a nanoscale microstructure
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/52—Electrically conductive inks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B5/00—Non-insulated conductors or conductive bodies characterised by their form
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2301/00—Metallic composition of the powder or its coating
    • B22F2301/25—Noble metals, i.e. Ag Au, Ir, Os, Pd, Pt, Rh, Ru
    • B22F2301/255—Silver or gold

Definitions

  • the present invention relates to a method for producing silver nanowires, a silver nanowire obtained by the method, and an ink containing the silver nanowire.
  • silver nanowires have attracted attention as raw materials for highly transparent and highly conductive thin films that can be substituted for ITO (indium tin oxide) films used for transparent electrodes such as touch panels.
  • Such silver nanowires are generally produced by heating a silver compound in the presence of a polyol such as polyvinylpyrrolidone and ethylene glycol (Patent Document 1, Non-Patent Document 1).
  • Patent Document 2 Although polyvinylpyrrolidone has solubility in glycol and water, in the above reaction, in order to control the wire diameter of silver nanowires, chloride salts and other inorganic salts often coexist (Patent Document 2). When these are present, the solubility of polyvinyl pyrrolidone in glycol and water decreases. For this reason, it has been difficult to deposit after the reaction so that polyvinylpyrrolidone adheres to the surface of the silver nanowire grown in the presence of these, and to remove it by washing.
  • the subject of this invention is providing the silver nanowire manufacturing method with which the washing
  • one embodiment of the present invention is a method for producing a silver nanowire, wherein R-CONHR ′ (R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ′ is In the presence of a polymer having a weight average molecular weight of 100,000 to 280000 and a reducing agent containing a secondary amide compound represented by a alkenyl group having a carbon-carbon double bond and having 2 or 3 carbon atoms in the monomer unit. And a step of heating the silver compound.
  • R-CONHR ′ R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ′ is In the presence of a polymer having a weight average molecular weight of 100,000 to 280000 and a reducing agent containing a secondary amide compound represented by a alkenyl group having a carbon-carbon double bond and having 2 or 3 carbon atoms in the monomer unit.
  • the polymer of the above compound is preferably at least one polymer selected from poly (N-vinylformamide), poly (N-vinylacetamide) or poly (N-vinylpropionamide).
  • the silver compounds are silver nitrate, hexafluorophosphate silver, silver borofluoride, silver perchlorate, silver chlorate, silver chloride, silver bromide, silver fluoride, silver carbonate, silver sulfate, silver acetate, trifluoro. It is preferably any of silver acetate.
  • polyol is preferably a divalent to hexavalent alcohol compound having 2 to 6 carbon atoms.
  • the method for producing the silver nanowire it is preferable to use 10,000 to 100,000 parts by weight of polyol with respect to 100 parts by weight of the silver compound.
  • the method for producing the silver nanowire further adds a quaternary ammonium salt.
  • the method for producing silver nanowires further includes a step of removing a polymer attached to the surface of the obtained silver nanowires.
  • another embodiment of the present invention is a silver nanowire, which is obtained by any one of the above-described silver nanowire manufacturing methods.
  • Still another embodiment of the present invention is an ink, characterized in that it contains the silver nanowire.
  • the cleaning process during the production of silver nanowires can be greatly simplified.
  • FIG. 3 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of the silver nanowires obtained in Example 1.
  • FIG. 6 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of silver nanowires obtained in Example 2.
  • FIG. 6 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of the silver nanowires obtained in Example 3.
  • FIG. 6 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of silver nanowires obtained in Example 4.
  • FIG. 6 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of the silver nanowires obtained in Example 5.
  • FIG. 6 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of the silver nanowires obtained in Example 6.
  • FIG. 10 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of the silver nanowires obtained in Example 7.
  • FIG. 10 is a diagram showing a field emission scanning electron microscope (FE-
  • the method for producing a silver nanowire according to the present embodiment includes R-CONHR ′ (R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ′ represents the number of carbon atoms having a carbon-carbon double bond. And a step of heating the silver compound in the presence of a polymer containing a secondary amide compound represented by 2 or 3 alkenyl group) as a monomer unit and a reducing agent.
  • Silver nanowires refer to silver nanofibers with a diameter on the order of nanometers.
  • Examples of the silver compound include silver salts, which may be used singly or in combination of two or more.
  • reaction can be performed homogeneously by using a silver compound soluble in the solvent which melt
  • the above silver salts are roughly classified into inorganic salts and organic salts, but inorganic salts are preferred from the viewpoint of industrial availability.
  • silver compound silver nitrate (AgNO 3), hexafluorophosphate silver (AgPF 6), ⁇ halide (AgBF 4), silver perchlorate (AgClO 4), silver perchlorate (AgClO 3), chloride Silver (AgCl), silver bromide (AgBr), silver fluoride (AgF), silver carbonate (Ag 2 CO 3 ), silver sulfate (Ag 2 SO 4 ), silver acetate (AgO 2 CCH 3 ), silver trifluoroacetate (AgO 2 CCF 3 ), and from the viewpoint of obtaining the production efficiency of the silver nanowire and the shape of the target silver nanowire, silver nitrate, silver perchlorate, silver chlorate, silver fluoride, hexafluorophosphate silver, Silver borofluoride and silver trifluoroacetate are preferred, and silver nitrate, hexafluorophosphate silver, silver borofluoride and silver trifluoroa
  • the silver concentration in the reaction solution is preferably in the range of 0.05 to 2% by mass as metal silver, more preferably in the range of 0.06 to 1% by mass, and in the range of 0.07 to 0.5% by mass. It is particularly preferable for obtaining a silver nanowire having a diameter.
  • the polymer (polymer) containing the secondary amide compound in the monomer unit used in the present embodiment acts as a capping agent in the silver nanowire synthesis stage.
  • the capping agent is a substance (ion, surfactant, etc.) adsorbed on a specific surface of the generated nucleus, and controls the shape of the generated particles by suppressing the growth rate of the surface.
  • thin and long nanowires can be obtained by selecting those that adsorb to the side portions of the nanowires.
  • the capping agent is outlined in the following non-patent literature, for example. Xia, et al. Acc. Chem. Res. 2007, 40, 1067. ⁇ Nobuyuki Korezu, Journal of Japanese Society for Crystal Growth, 2010, 37, No. 4, 281
  • Examples of the capping agent include R-CONHR ′ (R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ′ represents an alkenyl group having 2 or 3 carbon atoms having a carbon-carbon double bond. And a polymer having a monomer unit of the secondary amide compound which is a derivative of formic acid, acetic acid, propionic acid and butyric acid, which is a carboxylic acid having a relatively hydrophilic carbon atom number of 3 or less.
  • R ′ include a vinyl group, an isopropenyl group, and an allyl group.
  • the capping agent examples include poly (N-vinylformamide), poly (N-vinylacetamide), and poly (N-vinylpropionamide).
  • the capping agent can be easily washed from the produced silver nanowire by heating the silver compound in the presence of one or more polymers selected from such polymers and a reducing agent. it can.
  • the polymer is not only a single polymer selected from poly (N-vinylformamide), poly (N-vinylacetamide) or poly (N-vinylpropionamide) or a mixture as a polymer, but also the secondary amide.
  • Copolymers with other polymerizable monomers containing the compound in monomer units can also be used.
  • examples of other polymerizable monomers include acrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, phenyl (meth) acrylate, acrylamide, N, N-dimethylacrylamide and the like. It is done.
  • the secondary amide monomer unit in the copolymer is preferably in the range of 20 to 95 mol%, more preferably 30 to 90 mol%.
  • these polymers have a hydrogen atom bonded to the nitrogen atom constituting the amide group, and have a high affinity with the (hydrophilic) reaction solvent described later, so the protective colloid properties are low.
  • the range of molecular weights of the polymers that can be used to obtain them.
  • the total amount of the polymer used is not particularly limited, but is usually about 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass with respect to 1 part by mass of the silver compound. If it is lower than 0.5 parts by mass, it cannot be effectively adsorbed, and if it exceeds 20 parts by mass, the viscosity of the reaction solution becomes too high, which is not preferable.
  • the heating of the silver compound in the presence of the polymer can be performed in the presence of an alkali metal inorganic acid salt together with the polymer.
  • the alkali metal inorganic acid salt is preferably an alkali metal nitrate or alkali metal nitrite, more preferably an alkali metal nitrate.
  • potassium nitrate sodium nitrate
  • potassium nitrite sodium nitrite and the like, and any of these may be used alone or in combination.
  • the total amount of the alkali metal inorganic acid salt used is not particularly limited, but is usually about 0.05 to 2 molar equivalents, preferably 0.1 to 1 molar equivalents, per 1 mol of the silver compound.
  • an alkali metal halide may be used together with this.
  • alkali metal halides include alkali metal chlorides such as sodium chloride and potassium chloride; alkali metal bromides such as sodium bromide and potassium bromide; alkali metal iodides such as sodium iodide and potassium iodide. Any of these may be used alone or in combination.
  • the total amount of the alkali metal halide used is not particularly limited, but is usually about 1 ⁇ 10 ⁇ 7 to 3 ⁇ 10 ⁇ 1 molar equivalent, preferably 1 ⁇ 10 ⁇ 6 to 1 ⁇ , per 1 mol of the silver compound. 10 -2 molar equivalents.
  • the total amount of alkali metal halide used is less than 1 ⁇ 10 ⁇ 7 molar equivalent, selective growth into a silver nanowire shape is not promoted and the yield of the wire is extremely reduced.
  • the total amount of alkali metal halide used exceeds 3 ⁇ 10 ⁇ 1 molar equivalent, the yield of coarse silver particles increases and the yield decreases extremely.
  • a quaternary ammonium salt may be used together with the polymer.
  • Such quaternary ammonium salts include quaternary ammonium chlorides such as tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, hexadecyltrimethylammonium chloride, tetramethylammonium bromide, bromide bromide.
  • Quaternary ammonium bromides such as tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, hexadecyltrimethylammonium bromide and the like can be mentioned, and any of these may be used alone or in combination. .
  • tetrabutylammonium chloride and tetrabutylammonium bromide are preferable from the viewpoint of the obtained wire shape.
  • the total amount of the quaternary ammonium salt used is not particularly limited, but is usually about 0 to 1 molar equivalent, preferably 0 to 0.5 molar equivalent, relative to 1 mol of the silver compound.
  • the above heating is performed in the presence of a reducing agent.
  • the silver compound is reduced by the reducing agent, and metallic silver is deposited.
  • the reducing agent those having a known reducing action, for example, hydrogen gas, hydrazine, sodium borohydride, lithium aluminum hydride and the like can be used, but those that can also be used as a solvent described later may be used. From the viewpoint of safety and economy.
  • the above heating needs to be performed in the presence of a solvent in a state where the silver compound is dissolved or dispersed.
  • a solvent examples include polyol, water, monohydric alcohol, and the like. From the viewpoint of obtaining a reducing action, a solvent containing a polyol is preferable.
  • polyol examples include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, polyethylene glycol 300, propylene glycol, dipropylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2- Dihydric alcohols such as butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol; trihydric alcohols such as glycerin; pentaerythritol, diglycerin, ditrile Examples include tetravalent alcohols such as methylolpropane and hexavalent alcohols such as sorbitol, and any of these may be used alone or in combination.
  • a bivalent to hexavalent alcohol compound having 2 to 6 carbon atoms is more preferable in terms of a high boiling point and a high temperature at normal pressure, and a reducing property.
  • the use of a polyol as a solvent eliminates the need for a separate reducing agent.
  • dihydric alcohols are more preferable from the viewpoint of not having high viscosity, and ethylene glycol and propylene glycol are particularly preferable from the viewpoint of economy.
  • the total amount of the polyol used is not particularly limited, but is usually about 10,000 to 100,000 parts by weight, preferably 15,000 to 60,000 parts by weight with respect to 100 parts by weight of the silver compound. If the amount is less than this, the reduction rate becomes slow, and if it is more, the productivity tends to deteriorate.
  • the total amount of the solvent containing or not containing the polyol as a solvent is not particularly limited, but is usually about 10,000 to 100,000 parts by weight, preferably 15,000 to 60,000 parts by weight with respect to 100 parts by weight of the silver compound. .
  • the total amount of the solvent used is less than 10000 parts by mass, the silver concentration in the reaction solution is too high, and side reactions such as spherical powder formation may occur and the yield of the wire may decrease.
  • the total amount of the solvent used exceeds 100000 parts by mass, the silver concentration in the reaction solution is too low, the reaction rate is lowered, and the productivity is lowered.
  • the heating temperature of the silver compound is not particularly limited, but is usually 60 to 300 ° C., preferably 100 to 200 ° C.
  • the heating time is usually 0.1 to 48 hours, preferably 0.2 to 24 hours.
  • the silver nanowire produced by the heating step is purified by centrifugation, crossflow filtration, etc. to remove the capping agent attached to the surface, but the capping agent used in this embodiment is compared with polyvinylpyrrolidone. Because of its high water solubility, it can be removed with a simple washing process. Solvents that can be used for washing include water, methanol, ethanol, isopropyl alcohol, n-propyl alcohol, n-butanol, isobutanol, sec-butanol, etc. Among them, methanol, ethanol, isopropyl alcohol are industrial. It is preferable in terms of availability and easiness of solvent exchange in a subsequent process.
  • the silver nanowires obtained by the production method described above have very little residue derived from the capping agent, the resistance after the ink is prepared and applied is easily reduced, and the dispersibility in an aqueous solvent is particularly improved. .
  • the diameter of the obtained silver nanowire is about 20 to 250 nm, and the length is about 1 to 50 ⁇ m.
  • the diameter and length of silver nanowire according to the method as described in the Example mentioned later.
  • the ink according to this embodiment contains silver nanowires obtained by the above production method.
  • the content of silver nanowires in the ink is preferably large from the viewpoint of improving the conductivity of the pattern formed by the ink, but has an upper limit from the viewpoint of suppressing optical properties and aggregation, and is 0.05 to 60. % By mass is preferable, and 0.1 to 30% by mass is more preferable.
  • it is preferably 0.05 to 10% by mass, more preferably 0.1 to 5% by mass in consideration of light transmittance.
  • the solvent contained in the ink of the present embodiment is not particularly limited.
  • water alcohol solvents such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol; acetone, methyl ethyl ketone, Ketone solvents such as methyl isobutyl ketone; alkylene glycol solvents such as ethylene glycol, diethylene glycol, propylene glycol, and 1,3-propanediol; hydrocarbon solvents such as alkyl ethers of alkylene glycol, terpineol, toluene, and hexane It is done. These may be used individually by 1 type and may use 2 or more types together.
  • poly (N-vinylformamide), poly (N-vinylacetamide) or poly (N-vinylpropionamide) is used.
  • organic solvents more hydrophobic
  • the amount of these added is not particularly limited, but is usually about 0.01 to 10 parts by mass, preferably 0.01 to 1 part by mass with respect to 100 parts by mass of silver nanowires.
  • binder resin polyurethane resin, cellulose resin, polyacetal resin, polyalkylene glycol resin, etc.
  • binder resin components polyurethane resin, cellulose resin, polyacetal resin, polyalkylene glycol resin, etc.
  • the ink of the present embodiment includes various additives other than those described above (for example, surfactants, polymerizable compounds, polymers, antioxidants, corrosion inhibitors, viscosity modifiers, antiseptics, etc.) Agent).
  • additives for example, surfactants, polymerizable compounds, polymers, antioxidants, corrosion inhibitors, viscosity modifiers, antiseptics, etc.
  • the substrate on which the ink of the present embodiment is printed is not particularly limited, and examples thereof include insulating materials such as resin, glass, ceramic, and paper, semiconductor materials, and conductors such as metal.
  • the resin substrate include a polyethylene terephthalate substrate, a triacetyl cellulose substrate, a polyethylene naphthalate substrate, a polycarbonate substrate, a polyester substrate, an acrylonitrile-butadiene-styrene substrate, and a polyacryl substrate.
  • GPC gel permeation chromatography
  • Measuring apparatus HPLC manufactured by Shodex Eluent: Distilled water Detector: shodex RI-201I Pump: SHIMADZU LC-20AD Column oven: SHODEX AO-30C Analysis device: SHIMAZU SIC 480II Data Station Pump flow rate: 0.7 mL / min Column: 2 Shodex GPC SB-806 HQ Column temperature: 40 ° C Sample concentration: 0.2% by mass Injection volume: 200 ⁇ L
  • the shape (length / diameter) of the silver nanowires was determined by observing the diameter of 100 nanowires using an ultra high resolution field emission scanning electron microscope SU8020 (acceleration voltage 3 to 10 kV) manufactured by Hitachi High-Technologies Corporation.
  • Thermogravimetric analysis of the purified sample was performed using TG / DTA manufactured by NETZSCH.
  • Synthesis Example 1 Synthesis of poly (N-vinylformamide) N-vinylformamide (Tokyo Chemical Industry Co., Ltd., 100 g, 1.41 mol) and 400 g of pure water were added to a 1 L three-necked flask and completely dissolved. The liquid phase was replaced with nitrogen gas for 2 hours (nitrogen gas flow for the gas phase and nitrogen gas bubbling for the liquid phase). Only the substitution of nitrogen gas in the liquid phase was stopped, and the temperature was raised to 60 ° C. with the gas phase flowing in the nitrogen gas flow.
  • V-50 manufactured by Wako Pure Chemical Industries, Ltd., 0.9 g, 3.32 mmol
  • 10 g of pure water was added to the system using a syringe.
  • the reaction solution is put into a vat and placed in an oven.
  • the temperature is slowly raised to 120 ° C while watching the drying condition at normal pressure, and finally transferred to a vacuum oven.
  • 77 g of poly (N-vinylformamide) was obtained as a white solid.
  • Mw was 160000.
  • Example 1 Production of Silver Nanowire
  • a reaction vessel for personal organic synthesizer PPS-CTRL1 manufactured by Tokyo Rika Kikai Co., Ltd. 20 g of propylene glycol and 0.68 g of poly (N-vinylformamide) synthesized in Synthesis Example 1 (9 .6 mmol) was added and stirred at 60 ° C. for 1 hour for complete dissolution.
  • a vial 0.3 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 4 g of propylene glycol were added and completely dissolved by stirring at room temperature.
  • a dropping funnel was installed at the top of the reaction vessel and the silver nitrate solution prepared earlier was added. did. Nitrogen gas was passed through the branch pipe at a flow rate of 300 mL / min for 5 minutes to replace the system with nitrogen gas. The nitrogen gas in the branch pipe was stopped, a thermometer was installed, and the temperature was raised until the internal temperature reached 130 ° C. The contents of the dropping funnel were dropped over 6 minutes at an internal temperature of 130 ° C., and the reaction was further continued at 130 ° C. for 1 hour.
  • AROS tetrabutylammonium chloride
  • the reaction mixture was diluted 5-fold with ethanol, and silver nanowires were precipitated by treating with a centrifuge at a rotation speed of 6000 rpm for 5 minutes.
  • the operation of adding 50 g of ethanol and treating at 6000 rpm for 5 minutes was further performed twice to wash the poly (N-vinylformamide) and the solvent remaining in the system.
  • the shape of the obtained wire was measured using a field emission scanning electron microscope (FE-SEM).
  • the shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
  • Example 2 Production of Silver Nanowire Instead of 0.68 g (9.6 mmol) of poly (N-vinylformamide) synthesized in Synthesis Example 1, poly (N-vinylacetamide) (hereinafter abbreviated as PNVA)
  • PNVA poly (N-vinylacetamide)
  • a silver nanowire was obtained under the same conditions as in Example 1 except that GP191-405 (Mw: 130000, 0.817 g, 9.6 mmol) was used and the reaction time at 130 ° C. was changed from 1 hour to 20 minutes. Then, the shape of the wire was measured.
  • the shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
  • FE-SEM field emission scanning electron microscope
  • Example 3 A silver nanowire was obtained under the same conditions as in Example 2 except that GP191-405 (Mw: 260000) was used as PNVA, and the shape of the wire was measured.
  • the shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
  • Example 4 A silver nanowire was obtained under the same conditions as in Example 2 except that GE191-205 (Mw: 180000) was used as PNVA, and the shape of the wire was measured. The shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
  • GE191-205 Mw: 180000
  • FE-SEM field emission scanning electron microscope
  • Example 5 9-to-1 copolymer of N-vinylacetamide and acrylonitrile instead of 0.68 g (9.6 mmol) of poly (N-vinylformamide) synthesized in Synthesis Example 1 (hereinafter referred to as NVA / AN)
  • NVA / AN poly (N-vinylformamide) synthesized in Synthesis Example 1
  • Silver nanowires were obtained under the same conditions as in Example 1 except that 0.82 g (9.6 mmol) was used, and the shape of the wires was measured.
  • the shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
  • FE-SEM field emission scanning electron microscope
  • Example 6 instead of 0.68 g (9.6 mmol) of poly (N-vinylformamide) synthesized in Synthesis Example 1, a 9-to-1 copolymer of N-vinylacetamide and methyl methacrylate (hereinafter referred to as NVA / MMA) Silver nanowires were obtained under the same conditions as in Example 1 except that 0.82 g (9.6 mmol) manufactured by Mw: 150,000) was used, and the shape of the wires was measured. The shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
  • NVA / MMA 9-to-1 copolymer of N-vinylacetamide and methyl methacrylate
  • Example 7 Propylene glycol 20 g and PNVA GP191-405 (Mw: 130000) 0.54 g (6.4 mmol) were placed in a reaction vessel for the personal organic synthesizer PPS-CTRL1 manufactured by Tokyo Rika Kikai Co., Ltd., and stirred at 60 ° C. for 1 hour. To completely dissolve. 0.075 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 1 g of propylene glycol were placed in a vial and stirred completely at room temperature for complete dissolution.
  • PPS-CTRL1 personal organic synthesizer
  • a dropping funnel was installed at the top of the reaction vessel and the silver nitrate solution prepared earlier was added. did. Nitrogen gas was supplied from the branch pipe at a flow rate of 300 mL / min to replace the system with nitrogen gas, and the temperature was increased until the internal temperature reached 130 ° C. The contents of the dropping funnel were added dropwise at an internal temperature of 130 ° C. over 1 minute, and the reaction was further continued at 130 ° C. for 1 hour.
  • AROS tetrabutylammonium chloride
  • the reaction mixture was diluted 5-fold with ethanol, and silver nanowires were precipitated by treating with a centrifuge at a rotation speed of 6000 rpm for 5 minutes.
  • the operation of adding 50 g of ethanol and treating at 6000 rpm for 5 minutes was further performed twice to wash away PNVA and the solvent remaining in the system.
  • the shape of the wire was measured using a field emission scanning electron microscope (FE-SEM).
  • the shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
  • Example 8 A 1 L four-necked flask (mechanical stirrer, dropping funnel, reflux tube, thermometer) was charged with 200 g of propylene glycol and PNVA GP191-405 (Mw: 130000, 8.17 g, 96 mmol) and stirred at 60 ° C. for 1 hour. It was completely dissolved. In a beaker, 3 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 40 g of propylene glycol were placed and stirred at room temperature for complete dissolution.
  • PNVA GP191-405 Mw: 130000, 8.17 g, 96 mmol
  • the reaction mixture was diluted 4 times with methanol, and washed using a cross flow filtration apparatus (NGK Filtech Corp., Selfif tabletop tester, pore size 2 ⁇ m). Table 2 shows the washing conditions and the analysis results by TG / DTA.
  • Comparative Example 1 A silver nanowire manufacturing process was performed under the same conditions as in Example 2 except that GE191-104 (Mw: 300,000) was used as PNVA. The shape of the product is shown in Table 1.
  • the shape of the product in this comparative example was spherical, and silver nanowires could not be produced. This is probably because the weight average molecular weight Mw of PNVA was as high as 300000.
  • Comparative Example 2 A silver nanowire manufacturing process was performed under the same conditions as in Example 2 except that GE191-405P (Mw: 80000) was used as PNVA. The shape of the product is shown in Table 1.
  • the shape of the product in this comparative example was fine, and silver nanowires could not be produced. This is probably because the weight average molecular weight Mw of PNVA was as low as 80000.
  • Comparative Example 3 1 L four-necked flask (mechanical stirrer, dropping funnel, reflux tube, thermometer) with propylene glycol 200 g, polyvinylpyrrolidone K-90 (hereinafter abbreviated as PVP K-90, manufactured by Wako Pure Chemical Industries, Ltd.) 10.7 g ( 96 mmol) was added and stirred at 60 ° C. for 1 hour for complete dissolution. 3 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 80 g of propylene glycol were placed in a beaker and stirred at room temperature for complete dissolution.
  • PVP K-90 polyvinylpyrrolidone K-90
  • the reaction mixture was diluted 4 times with methanol, and washed using a cross flow filtration apparatus (NGK Filtech Corp., Selfif tabletop tester, pore size 2 ⁇ m). Table 2 shows the washing conditions and the analysis results by TG / DTA.
  • Example 8 using PNVA After the filtration washing process by cross flow filtration was repeated 6 times, in Example 8 using PNVA, the residual amount of resin was 0.05% by mass, whereas in Comparative Example 3 using PVP, 0.29% by mass. It can be seen that a large amount of resin cannot be cleaned.

Abstract

Provided are: a method for producing silver nanowires, wherein produced silver nanowires are able to be easily cleaned; silver nanowires which are obtained by this method; and an ink which contains the silver nanowires. Silver nanowires according to the present invention are produced by heating a silver compound in the presence of a reducing agent and a polymer which has a weight average molecular weight of 100,000-280,000, and which contains, as a monomer unit, a secondary amide compound that is represented by R-CONHR' (wherein R represents a hydrogen atom or an alkyl group having 1-3 carbon atoms; and R' represents an alkenyl group having 2 or 3 carbon atoms and a carbon-carbon double bond). The polymer of the compound is one or more polymers selected from among poly(N-vinyl formaldehyde), poly(N-vinyl acetamide) and poly(N-vinyl propionamide).

Description

銀ナノワイヤーの製造方法、該方法で得られた銀ナノワイヤー及び該銀ナノワイヤーを含有するインクSilver nanowire manufacturing method, silver nanowire obtained by the method, and ink containing the silver nanowire
　本発明は、銀ナノワイヤーの製造方法、該方法で得られた銀ナノワイヤー及び該銀ナノワイヤーを含有するインクに関する。 The present invention relates to a method for producing silver nanowires, a silver nanowire obtained by the method, and an ink containing the silver nanowire.
　タッチパネル等の透明電極に使用されるＩＴＯ（酸化インジウムスズ）膜の代替となる高透明性・高導電性薄膜の原料として、銀ナノワイヤーが近年注目されている。斯かる銀ナノワイヤーは、一般に、ポリビニルピロリドンとエチレングリコール等のポリオールの存在下に銀化合物を加熱することによって製造されている（特許文献１、非特許文献１）。 In recent years, silver nanowires have attracted attention as raw materials for highly transparent and highly conductive thin films that can be substituted for ITO (indium tin oxide) films used for transparent electrodes such as touch panels. Such silver nanowires are generally produced by heating a silver compound in the presence of a polyol such as polyvinylpyrrolidone and ethylene glycol (Patent Document 1, Non-Patent Document 1).
　しかしながら、ポリビニルピロリドンはグリコールや水に対する溶解性を有するものの、上記反応では、銀ナノワイヤーのワイヤー径をコントロールするために塩化物塩や他の無機塩を共存させることが多く（特許文献２）、これらが存在するとポリビニルピロリドンのグリコールや水に対する溶解度が低下する。そのためかこれらの存在下で成長させた銀ナノワイヤー表面にはポリビニルピロリドンが付着するように析出し反応後に洗浄によって除去することは困難であった。このようなポリビニルピロリドンが残存した銀ナノワイヤーを用いた場合には、大過剰のアルコールを用いて銀ナノワイヤーを洗浄しないと、銀ナノワイヤー上のポリビニルピロリドンを除去できないという欠点があった。銀ナノワイヤーをインク化する際には、印刷する基材によって水やアルコール、有機溶媒等を使い分ける必要があるが、銀ナノワイヤー表面にポリビニルピロリドンが残存した場合には、導電性薄膜の抵抗を下げるのに銀ナノワイヤー表面のポリビニルピロリドンを除去するための強いエネルギーが必要になる上、分散媒、特に疎水性の分散媒に対する分散性が十分でなく、更に分散剤を添加する必要があった。 However, although polyvinylpyrrolidone has solubility in glycol and water, in the above reaction, in order to control the wire diameter of silver nanowires, chloride salts and other inorganic salts often coexist (Patent Document 2). When these are present, the solubility of polyvinyl pyrrolidone in glycol and water decreases. For this reason, it has been difficult to deposit after the reaction so that polyvinylpyrrolidone adheres to the surface of the silver nanowire grown in the presence of these, and to remove it by washing. In the case of using silver nanowires in which such polyvinyl pyrrolidone remains, there is a drawback that polyvinyl pyrrolidone on the silver nanowires cannot be removed unless the silver nanowires are washed with a large excess of alcohol. When making silver nanowires into ink, it is necessary to use water, alcohol, organic solvent, etc. properly depending on the substrate to be printed, but when polyvinylpyrrolidone remains on the surface of silver nanowires, the resistance of the conductive thin film is reduced. In order to lower the level, strong energy is required to remove polyvinylpyrrolidone on the surface of the silver nanowires, and the dispersibility of the dispersion medium, particularly the hydrophobic dispersion medium, is insufficient, and a dispersant must be added. .
米国特許第７，５８５，３４９号明細書US Pat. No. 7,585,349 米国特許第８，５１２，４３８号明細書US Pat. No. 8,512,438
　したがって、本発明の課題は、製造後の銀ナノワイヤーの洗浄が容易な銀ナノワイヤーの製造方法、該方法で得られた銀ナノワイヤー及び該銀ナノワイヤーを含有するインクを提供することにある。 Therefore, the subject of this invention is providing the silver nanowire manufacturing method with which the washing | cleaning of the silver nanowire after manufacture is easy, the silver nanowire obtained by this method, and the ink containing this silver nanowire. .
　上記目的を達成するために、本発明の一実施形態は、銀ナノワイヤーの製造方法であって、Ｒ－ＣＯＮＨＲ’（Ｒは水素原子または炭素原子数が１～３のアルキル基、Ｒ’は炭素－炭素二重結合を有する炭素原子数が２または３のアルケニル基）で表される第二級アミド化合物をモノマー単位に含む重量平均分子量が１０００００～２８００００の重合体および還元剤の存在下で、銀化合物を加熱する工程を含むことを特徴とする。 In order to achieve the above object, one embodiment of the present invention is a method for producing a silver nanowire, wherein R-CONHR ′ (R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ′ is In the presence of a polymer having a weight average molecular weight of 100,000 to 280000 and a reducing agent containing a secondary amide compound represented by a alkenyl group having a carbon-carbon double bond and having 2 or 3 carbon atoms in the monomer unit. And a step of heating the silver compound.
　上記化合物の重合体は、ポリ（Ｎ－ビニルホルムアミド）、ポリ（Ｎ－ビニルアセトアミド）またはポリ（Ｎ－ビニルプロピオンアミド）から選ばれる１種以上の重合体であるのが好適である。 The polymer of the above compound is preferably at least one polymer selected from poly (N-vinylformamide), poly (N-vinylacetamide) or poly (N-vinylpropionamide).
　また、上記銀化合物は、硝酸銀、ヘキサフルオロホスフェート銀、硼弗化銀、過塩素酸銀、塩素酸銀、塩化銀、臭化銀、フッ化銀、炭酸銀、硫酸銀、酢酸銀、トリフルオロ酢酸銀のいずれかであるのが好適である。 The silver compounds are silver nitrate, hexafluorophosphate silver, silver borofluoride, silver perchlorate, silver chlorate, silver chloride, silver bromide, silver fluoride, silver carbonate, silver sulfate, silver acetate, trifluoro. It is preferably any of silver acetate.
　ポリオールを前記還元剤および／または溶媒として含むことが好適である。また、ポリオールが、炭素原子数２～６であり、２～６価のアルコール化合物であることが好適である。 It is preferable to contain polyol as the reducing agent and / or solvent. The polyol is preferably a divalent to hexavalent alcohol compound having 2 to 6 carbon atoms.
　また、上記銀ナノワイヤーの製造方法は、銀化合物１００質量部に対してポリオールを１００００～１０００００質量部用いるのが好適である。 In addition, in the method for producing the silver nanowire, it is preferable to use 10,000 to 100,000 parts by weight of polyol with respect to 100 parts by weight of the silver compound.
　また、上記銀ナノワイヤーの製造方法は、４級アンモニウム塩をさらに加えるのが好適である。 In addition, it is preferable that the method for producing the silver nanowire further adds a quaternary ammonium salt.
　また、上記銀ナノワイヤーの製造方法は、得られた銀ナノワイヤーの表面に付着した重合体を除去する工程をさらに含む。 The method for producing silver nanowires further includes a step of removing a polymer attached to the surface of the obtained silver nanowires.
　また、本発明の他の実施形態は、銀ナノワイヤーであって、上記いずれかの銀ナノワイヤーの製造方法で得られたことを特徴とする。 Further, another embodiment of the present invention is a silver nanowire, which is obtained by any one of the above-described silver nanowire manufacturing methods.
　また、本発明のさらに他の実施形態は、インクであって、上記銀ナノワイヤーを含有することを特徴とする。 Still another embodiment of the present invention is an ink, characterized in that it contains the silver nanowire.
　本発明によれば、銀ナノワイヤーの製造時の洗浄工程を大幅に簡略化できる。 According to the present invention, the cleaning process during the production of silver nanowires can be greatly simplified.
実施例１で得られた銀ナノワイヤーの電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を表す図である。3 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of the silver nanowires obtained in Example 1. FIG. 実施例２で得られた銀ナノワイヤーの電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を表す図である。6 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of silver nanowires obtained in Example 2. FIG. 実施例３で得られた銀ナノワイヤーの電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を表す図である。6 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of the silver nanowires obtained in Example 3. FIG. 実施例４で得られた銀ナノワイヤーの電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を表す図である。6 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of silver nanowires obtained in Example 4. FIG. 実施例５で得られた銀ナノワイヤーの電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を表す図である。6 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of the silver nanowires obtained in Example 5. FIG. 実施例６で得られた銀ナノワイヤーの電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を表す図である。6 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of the silver nanowires obtained in Example 6. FIG. 実施例７で得られた銀ナノワイヤーの電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を表す図である。10 is a diagram showing a field emission scanning electron microscope (FE-SEM) image of the silver nanowires obtained in Example 7. FIG.
　以下、本発明を実施するための形態（以下、実施形態という）を説明する。 Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described.
　本実施形態にかかる銀ナノワイヤーの製造方法は、Ｒ－ＣＯＮＨＲ’（Ｒは水素原子または炭素原子数が１～３のアルキル基を表し、Ｒ’は炭素－炭素二重結合を有する炭素原子数が２または３のアルケニル基）で表される第二級アミド化合物をモノマー単位に含む重合体および還元剤の存在下で銀化合物を加熱する工程を含むことを特徴とする。銀ナノワイヤーは、直径がナノメーターオーダーである銀のナノファイバーのことをいう。 The method for producing a silver nanowire according to the present embodiment includes R-CONHR ′ (R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ′ represents the number of carbon atoms having a carbon-carbon double bond. And a step of heating the silver compound in the presence of a polymer containing a secondary amide compound represented by 2 or 3 alkenyl group) as a monomer unit and a reducing agent. Silver nanowires refer to silver nanofibers with a diameter on the order of nanometers.
　上記銀化合物としては、銀塩が挙げられ、１種単独で又は２種以上を組み合わせて用いてもよい。なお、後述するアルカリ金属の無機酸塩を用いる場合は、該アルカリ金属の無機酸塩を溶解する溶媒に可溶な銀化合物を用いることで、反応を均質に行うことができる。 Examples of the silver compound include silver salts, which may be used singly or in combination of two or more. In addition, when using the alkali metal inorganic acid salt mentioned later, reaction can be performed homogeneously by using a silver compound soluble in the solvent which melt | dissolves this alkali metal inorganic acid salt.
　上記銀塩は無機塩と有機塩とに大別されるが、工業的入手の容易性の観点から、無機塩が好ましい。 The above silver salts are roughly classified into inorganic salts and organic salts, but inorganic salts are preferred from the viewpoint of industrial availability.
　銀化合物の具体例としては、硝酸銀（ＡｇＮＯ３）、ヘキサフルオロホスフェート銀（ＡｇＰＦ６）、硼弗化銀（ＡｇＢＦ４）、過塩素酸銀（ＡｇＣｌＯ４）、塩素酸銀（ＡｇＣｌＯ３）、塩化銀（ＡｇＣｌ）、臭化銀（ＡｇＢｒ）、フッ化銀（ＡｇＦ）、炭酸銀（Ａｇ２ＣＯ３）、硫酸銀（Ａｇ２ＳＯ４）、酢酸銀（ＡｇＯ２ＣＣＨ３）、トリフルオロ酢酸銀（ＡｇＯ２ＣＣＦ３）が挙げられ、銀ナノワイヤーの製造効率及び目的の銀ナノワイヤーの形状が得られる観点から、硝酸銀、過塩素酸銀、塩素酸銀、フッ化銀、ヘキサフルオロホスフェート銀、硼弗化銀、トリフルオロ酢酸銀が好ましく、硝酸銀、ヘキサフルオロホスフェート銀、硼弗化銀、トリフルオロ酢酸銀が溶媒への溶解性の観点から、より好ましい。反応液中の銀濃度は、金属銀として０．０５～２質量％の範囲が好ましく、０．０６～１質量％の範囲がより好ましく、０．０７～０．５質量％の範囲が、細径の銀ナノワイヤーを得るためには特に好ましい。 Specific examples of the silver compound, silver nitrate (AgNO 3), hexafluorophosphate silver (AgPF 6),硼弗halide (AgBF 4), silver perchlorate (AgClO 4), silver perchlorate (AgClO 3), chloride Silver (AgCl), silver bromide (AgBr), silver fluoride (AgF), silver carbonate (Ag 2 CO 3 ), silver sulfate (Ag 2 SO 4 ), silver acetate (AgO 2 CCH 3 ), silver trifluoroacetate (AgO 2 CCF 3 ), and from the viewpoint of obtaining the production efficiency of the silver nanowire and the shape of the target silver nanowire, silver nitrate, silver perchlorate, silver chlorate, silver fluoride, hexafluorophosphate silver, Silver borofluoride and silver trifluoroacetate are preferred, and silver nitrate, hexafluorophosphate silver, silver borofluoride and silver trifluoroacetate are more preferred from the viewpoint of solubility in a solvent. The silver concentration in the reaction solution is preferably in the range of 0.05 to 2% by mass as metal silver, more preferably in the range of 0.06 to 1% by mass, and in the range of 0.07 to 0.5% by mass. It is particularly preferable for obtaining a silver nanowire having a diameter.
　本実施形態で用いる上記第二級アミド化合物をモノマー単位に含む重合体（ポリマー）は、銀ナノワイヤーの合成段階でキャッピング剤として作用する。キャッピング剤とは、生成してくる核の特定の面に吸着する物質（イオン，界面活性剤など）であり、その面の成長速度を抑制して、生成する粒子の形状を制御する。銀のナノワイヤーの場合にはナノワイヤーの側面の部分に吸着するようなものを選ぶことにより、細くて長いナノワイヤーを得ることが出来る。キャッピング剤に関しては、例えば以下の非特許文献に概説されている。
　　・Xia, et al. Acc. Chem. Res. 2007, 40, 1067.
　　・是津信行, 日本結晶成長学会誌, 2010, 37, No. 4, 281 The polymer (polymer) containing the secondary amide compound in the monomer unit used in the present embodiment acts as a capping agent in the silver nanowire synthesis stage. The capping agent is a substance (ion, surfactant, etc.) adsorbed on a specific surface of the generated nucleus, and controls the shape of the generated particles by suppressing the growth rate of the surface. In the case of silver nanowires, thin and long nanowires can be obtained by selecting those that adsorb to the side portions of the nanowires. The capping agent is outlined in the following non-patent literature, for example.
Xia, et al. Acc. Chem. Res. 2007, 40, 1067.
・ Nobuyuki Korezu, Journal of Japanese Society for Crystal Growth, 2010, 37, No. 4, 281
　上記キャッピング剤としては、Ｒ－ＣＯＮＨＲ’（Ｒは水素原子または炭素原子数が１～３のアルキル基を表し、Ｒ’は炭素－炭素二重結合を有する炭素原子数が２または３のアルケニル基）で表される、比較的親水性の炭素原子数が３以下のカルボン酸であるギ酸、酢酸、プロピオン酸、酪酸の誘導体である上記第二級アミド化合物をモノマー単位に含むポリマーが挙げられる。Ｒ’の具体例としては、ビニル基、イソプロペニル基、アリル基が挙げられる。キャッピング剤の具体例としては、ポリ（Ｎ－ビニルホルムアミド）、ポリ（Ｎ－ビニルアセトアミド）、ポリ（Ｎ－ビニルプロピオンアミド）が好適である。本実施形態では、このようなポリマーから選ばれる１種以上のポリマーおよび還元剤の存在下で、銀化合物を加熱することによって、製造した銀ナノワイヤーからのキャッピング剤の洗浄を容易に行うことができる。 Examples of the capping agent include R-CONHR ′ (R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ′ represents an alkenyl group having 2 or 3 carbon atoms having a carbon-carbon double bond. And a polymer having a monomer unit of the secondary amide compound which is a derivative of formic acid, acetic acid, propionic acid and butyric acid, which is a carboxylic acid having a relatively hydrophilic carbon atom number of 3 or less. Specific examples of R ′ include a vinyl group, an isopropenyl group, and an allyl group. Specific examples of the capping agent include poly (N-vinylformamide), poly (N-vinylacetamide), and poly (N-vinylpropionamide). In the present embodiment, the capping agent can be easily washed from the produced silver nanowire by heating the silver compound in the presence of one or more polymers selected from such polymers and a reducing agent. it can.
　なお、上記ポリマーは、ポリ（Ｎ－ビニルホルムアミド）、ポリ（Ｎ－ビニルアセトアミド）またはポリ（Ｎ－ビニルプロピオンアミド）から選ばれる単独のポリマーあるいはポリマーとしての混合物だけでなく、上記第二級アミド化合物をモノマー単位に含む他の重合性モノマーとのコポリマーを使用することもできる。他の重合性モノマーの例としてはアクリロニトリル、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸ブチル、（メタ）アクリル酸フェニル、アクリルアミド、Ｎ，Ｎ－ジメチルアクリルアミド等が挙げられる。他の重合性モノマーとのコポリマーを用いる場合はコポリマー中の第二級アミドモノマー単位が２０～９５ｍｏｌ％の範囲とすることが好ましく、３０～９０ｍｏｌ％であることがより好ましい。ただし、これらのポリマーはアミド基を構成する窒素原子に水素原子が結合しており、後述の（親水性）反応溶媒との親和性が高いため保護コロイド性が低く、銀化合物から銀ナノワイヤーを得るためには使用出来るポリマーの分子量の範囲に制約がある。 The polymer is not only a single polymer selected from poly (N-vinylformamide), poly (N-vinylacetamide) or poly (N-vinylpropionamide) or a mixture as a polymer, but also the secondary amide. Copolymers with other polymerizable monomers containing the compound in monomer units can also be used. Examples of other polymerizable monomers include acrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, phenyl (meth) acrylate, acrylamide, N, N-dimethylacrylamide and the like. It is done. When a copolymer with another polymerizable monomer is used, the secondary amide monomer unit in the copolymer is preferably in the range of 20 to 95 mol%, more preferably 30 to 90 mol%. However, these polymers have a hydrogen atom bonded to the nitrogen atom constituting the amide group, and have a high affinity with the (hydrophilic) reaction solvent described later, so the protective colloid properties are low. There are restrictions on the range of molecular weights of the polymers that can be used to obtain them.
　すなわち、これらのポリマーを用いる場合には重量平均分子量が１０００００～２８００００の範囲のポリマーを用いる必要があり、好ましくは１１００００～２５００００、より好ましくは１２００００～２０００００である。分子量が１０００００より小さいと、微粒子状の銀粒子しか得られず、また、分子量が２８００００を超えても、分子量が大きすぎて却って吸着しづらくなるためか、微粒子状の銀粒子の割合が増える傾向がある。 That is, when these polymers are used, it is necessary to use a polymer having a weight average molecular weight in the range of 100,000 to 280000, preferably 110,000 to 250,000, more preferably 120,000 to 200,000. If the molecular weight is less than 100,000, only fine silver particles can be obtained, and even if the molecular weight exceeds 280000, the molecular weight is too large to be easily adsorbed, or the proportion of fine silver particles tends to increase. There is.
　上記ポリマーの合計使用量は特に限定されないが、銀化合物１質量部に対し、通常０．５から２０質量部程度であり、好ましくは１質量部から１０質量部である。０．５質量部より低いと有効に吸着できず、２０質量部よりも多いと反応溶液の粘度が高くなりすぎ好ましくない。 The total amount of the polymer used is not particularly limited, but is usually about 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass with respect to 1 part by mass of the silver compound. If it is lower than 0.5 parts by mass, it cannot be effectively adsorbed, and if it exceeds 20 parts by mass, the viscosity of the reaction solution becomes too high, which is not preferable.
　また、上記ポリマーの存在下で行う銀化合物の加熱は、上記ポリマーとともにアルカリ金属の無機酸塩の存在下で行うことができる。斯かるアルカリ金属の無機酸塩としては、アルカリ金属の硝酸塩、アルカリ金属の亜硝酸塩が好ましく、アルカリ金属の硝酸塩がより好ましい。 The heating of the silver compound in the presence of the polymer can be performed in the presence of an alkali metal inorganic acid salt together with the polymer. The alkali metal inorganic acid salt is preferably an alkali metal nitrate or alkali metal nitrite, more preferably an alkali metal nitrate.
　具体的には、硝酸カリウム、硝酸ナトリウム、亜硝酸カリウム、亜硝酸ナトリウム等が挙げられ、これらのいずれかを単独で使用しても組み合わせて使用してもよい。 Specific examples include potassium nitrate, sodium nitrate, potassium nitrite, sodium nitrite and the like, and any of these may be used alone or in combination.
　上記アルカリ金属の無機酸塩の合計使用量は特に限定されないが、銀化合物１モルに対し、通常０．０５～２モル当量程度であり、好ましくは０．１～１モル当量である。 The total amount of the alkali metal inorganic acid salt used is not particularly limited, but is usually about 0.05 to 2 molar equivalents, preferably 0.1 to 1 molar equivalents, per 1 mol of the silver compound.
　また、アルカリ金属の無機酸塩を用いる場合、これと共にアルカリ金属ハロゲン化物を用いてもよい。斯かるアルカリ金属ハロゲン化物としては、塩化ナトリウム、塩化カリウム等のアルカリ金属塩化物；臭化ナトリウム、臭化カリウム等のアルカリ金属臭化物；ヨウ化ナトリウム、ヨウ化カリウム等のアルカリ金属ヨウ化物等が挙げられ、これらのいずれかを単独で使用しても組み合わせて使用してもよい。 Further, when an alkali metal inorganic acid salt is used, an alkali metal halide may be used together with this. Examples of such alkali metal halides include alkali metal chlorides such as sodium chloride and potassium chloride; alkali metal bromides such as sodium bromide and potassium bromide; alkali metal iodides such as sodium iodide and potassium iodide. Any of these may be used alone or in combination.
　上記アルカリ金属ハロゲン化物の合計使用量は特に限定されないが、銀化合物１モルに対し、通常１×１０－７～３×１０－１モル当量程度であり、好ましくは１×１０－６～１×１０－２モル当量である。アルカリ金属ハロゲン化物の合計使用量が１×１０－７モル当量未満では銀ナノワイヤー形状への選択的成長が促進されずワイヤーの収率が極端に低下する。またアルカリ金属ハロゲン化物の合計使用量が３×１０－1モル当量を超える場合は粗大銀粒子の生成割合が増大し収率が極端に低下する。 The total amount of the alkali metal halide used is not particularly limited, but is usually about 1 × 10 −7 to 3 × 10 −1 molar equivalent, preferably 1 × 10 −6 to 1 ×, per 1 mol of the silver compound. 10 -2 molar equivalents. When the total amount of alkali metal halide used is less than 1 × 10 −7 molar equivalent, selective growth into a silver nanowire shape is not promoted and the yield of the wire is extremely reduced. On the other hand, when the total amount of alkali metal halide used exceeds 3 × 10 −1 molar equivalent, the yield of coarse silver particles increases and the yield decreases extremely.
　また、上記加熱において、上記ポリマーとともに４級アンモニウム塩を用いてもよい。斯かる４級アンモニウム塩としては、塩化テトラメチルアンモニウム、塩化テトラエチルアンモニウム、塩化テトラプロピルアンモニウム、塩化テトラブチルアンモニウム、塩化ヘキサデシルトリメチルアンモニウム等の４級アンモニウム塩化物や、臭化テトラメチルアンモニウム、臭化テトラエチルアンモニウム、臭化テトラプロピルアンモニウム、臭化テトラブチルアンモニウム、臭化ヘキサデシルトリメチルアンモニウム等の４級アンモニウム臭化物等が挙げられ、これらのいずれかを単独で使用しても組み合わせて使用してもよい。これらの中でも、得られるワイヤー形状の観点から、塩化テトラブチルアンモニウム、臭化テトラブチルアンモニウムが好ましい。 In the heating, a quaternary ammonium salt may be used together with the polymer. Such quaternary ammonium salts include quaternary ammonium chlorides such as tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, hexadecyltrimethylammonium chloride, tetramethylammonium bromide, bromide bromide. Quaternary ammonium bromides such as tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, hexadecyltrimethylammonium bromide and the like can be mentioned, and any of these may be used alone or in combination. . Among these, tetrabutylammonium chloride and tetrabutylammonium bromide are preferable from the viewpoint of the obtained wire shape.
　上記４級アンモニウム塩の合計使用量は特に限定されないが、銀化合物１モルに対し、通常０～１モル当量程度であり、好ましくは０～０．５モル当量である。 The total amount of the quaternary ammonium salt used is not particularly limited, but is usually about 0 to 1 molar equivalent, preferably 0 to 0.5 molar equivalent, relative to 1 mol of the silver compound.
　また、上記加熱は還元剤の存在下で行う。還元剤により銀化合物が還元され金属銀が析出する。還元剤としては公知の還元作用を有するもの、例えば水素ガス、ヒドラジン、水素化ホウ素ナトリウム、水素化アルミニウムリチウム等を使用することが可能であるが、後述の溶媒として兼用できるものを使用することが、安全性、経済性の点で好ましい。 In addition, the above heating is performed in the presence of a reducing agent. The silver compound is reduced by the reducing agent, and metallic silver is deposited. As the reducing agent, those having a known reducing action, for example, hydrogen gas, hydrazine, sodium borohydride, lithium aluminum hydride and the like can be used, but those that can also be used as a solvent described later may be used. From the viewpoint of safety and economy.
　上記加熱は銀化合物を溶解または分散させた状態で溶媒の存在下で行う必要がある。溶媒としては、ポリオール、水、１価のアルコール等が挙げられ、還元作用を得る観点から、ポリオールを含む溶媒が好ましい。ポリオールとしては、エチレングリコール、ジエチレングリコール、トリエチレングリコール、ポリエチレングリコール２００、ポリエチレングリコール３００、プロピレングリコール、ジプロピレングリコール、１，３－プロパンジオール、２－メチル－１，３－プロパンジオール、１，２－ブタンジオール、１，４－ブタンジオール、１，５－ペンタンジオール、１，６－ヘキサンジオール、１，４－シクロヘキサンジオール等の２価アルコール；グリセリン等の３価アルコール；ペンタエリスリトール、ジグリセリン、ジトリメチロールプロパンのような４価のアルコール、ソルビトール等の６価アルコール等が挙げられ、これらのいずれかを単独で使用しても組み合わせて使用してもよい。炭素原子数が２～６であり、２～６価のアルコール化合物を使用すると沸点が高く常圧で温度を上げられる点と還元性の点でより好ましい。ポリオールを溶媒として使用することにより還元剤を別に用いる必要性もなくなる。 The above heating needs to be performed in the presence of a solvent in a state where the silver compound is dissolved or dispersed. Examples of the solvent include polyol, water, monohydric alcohol, and the like. From the viewpoint of obtaining a reducing action, a solvent containing a polyol is preferable. Examples of the polyol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, polyethylene glycol 300, propylene glycol, dipropylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2- Dihydric alcohols such as butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol; trihydric alcohols such as glycerin; pentaerythritol, diglycerin, ditrile Examples include tetravalent alcohols such as methylolpropane and hexavalent alcohols such as sorbitol, and any of these may be used alone or in combination. The use of a bivalent to hexavalent alcohol compound having 2 to 6 carbon atoms is more preferable in terms of a high boiling point and a high temperature at normal pressure, and a reducing property. The use of a polyol as a solvent eliminates the need for a separate reducing agent.
　上記ポリオールの中でも、高粘度にならないという観点で２価アルコールがさらに好ましく、その中でもエチレングリコール、プロピレングリコールが経済性の点で特に好ましい。 Among the above polyols, dihydric alcohols are more preferable from the viewpoint of not having high viscosity, and ethylene glycol and propylene glycol are particularly preferable from the viewpoint of economy.
　上記ポリオールの合計使用量は特に限定されないが、銀化合物１００質量部に対し、通常１００００～１０００００質量部程度であり、好ましくは１５０００～６００００質量部である。これよりも少ないと還元速度が遅くなり、多いと生産性が悪くなる傾向がある。 The total amount of the polyol used is not particularly limited, but is usually about 10,000 to 100,000 parts by weight, preferably 15,000 to 60,000 parts by weight with respect to 100 parts by weight of the silver compound. If the amount is less than this, the reduction rate becomes slow, and if it is more, the productivity tends to deteriorate.
　また、上記ポリオールを溶媒として含むまたは含まない上記溶媒の合計使用量は特に限定されないが、銀化合物１００質量部に対し、通常１００００～１０００００質量部程度であり、好ましくは１５０００～６００００質量部である。 In addition, the total amount of the solvent containing or not containing the polyol as a solvent is not particularly limited, but is usually about 10,000 to 100,000 parts by weight, preferably 15,000 to 60,000 parts by weight with respect to 100 parts by weight of the silver compound. .
　溶媒の合計使用量が１００００質量部未満の場合、反応液中の銀濃度が高すぎるため球状粉生成などの副反応が起こりワイヤーの収率が低下することがある。また溶媒の合計使用量が１０００００質量部を超えると、反応液中の銀濃度が低すぎるため反応速度が低下し、生産性が低下する。 When the total amount of the solvent used is less than 10000 parts by mass, the silver concentration in the reaction solution is too high, and side reactions such as spherical powder formation may occur and the yield of the wire may decrease. On the other hand, when the total amount of the solvent used exceeds 100000 parts by mass, the silver concentration in the reaction solution is too low, the reaction rate is lowered, and the productivity is lowered.
　また、銀化合物の加熱温度は特に限定されないが、通常６０～３００℃であり、好ましくは１００～２００℃である。また、加熱時間は、通常０．１～４８時間であり、好ましくは０．２～２４時間である。 The heating temperature of the silver compound is not particularly limited, but is usually 60 to 300 ° C., preferably 100 to 200 ° C. The heating time is usually 0.1 to 48 hours, preferably 0.2 to 24 hours.
　なお、上記加熱工程によって生成した銀ナノワイヤーは、その表面に付着したキャッピング剤を除去するために遠心分離、クロスフロー濾過等により精製するが、本実施形態で使用するキャッピング剤はポリビニルピロリドンに比べて水溶性が高いため、簡単な洗浄工程で除去することができる。洗浄に使用できる溶媒としては水、メタノール、エタノール、イソプロピルアルコール、ｎ－プロピルアルコール、ｎ－ブタノール、イソブタノール、ｓｅｃ－ブタノール等が挙げられるが、これらの中でもメタノール、エタノール、イソプロピルアルコールが工業的な入手容易性と、後工程での溶媒交換のやり易さの点で好ましい。 The silver nanowire produced by the heating step is purified by centrifugation, crossflow filtration, etc. to remove the capping agent attached to the surface, but the capping agent used in this embodiment is compared with polyvinylpyrrolidone. Because of its high water solubility, it can be removed with a simple washing process. Solvents that can be used for washing include water, methanol, ethanol, isopropyl alcohol, n-propyl alcohol, n-butanol, isobutanol, sec-butanol, etc. Among them, methanol, ethanol, isopropyl alcohol are industrial. It is preferable in terms of availability and easiness of solvent exchange in a subsequent process.
　以上に述べた製造方法で得られる銀ナノワイヤーにはキャッピング剤由来の残存物が非常に少なく、インクを調製し塗布した後の抵抗が容易に下がるとともに、特に水系溶媒への分散性が良くなる。 The silver nanowires obtained by the production method described above have very little residue derived from the capping agent, the resistance after the ink is prepared and applied is easily reduced, and the dispersibility in an aqueous solvent is particularly improved. .
　また、得られる銀ナノワイヤーの直径は、２０～２５０ｎｍ程度であり、長さは、１～５０μｍ程度である。なお、銀ナノワイヤーの直径及び長さは、後述する実施例に記載の方法に従い測定すればよい。 The diameter of the obtained silver nanowire is about 20 to 250 nm, and the length is about 1 to 50 μm. In addition, what is necessary is just to measure the diameter and length of silver nanowire according to the method as described in the Example mentioned later.
　本実施形態にかかるインクは、上記製造方法によって得られた銀ナノワイヤーを含有するものである。インク中の銀ナノワイヤーの含有量としては、インクにより形成されるパターンの導電性向上の観点からは多い方がよいが、光学特性や凝集を抑える観点からは上限があり、０．０５～６０質量％が好ましく、０．１～３０質量％がより好ましい。特に透明導電膜として用いる場合には光線透過率も考慮して、０．０５～１０質量％が好ましく、０．１～５質量％がより好ましい。 The ink according to this embodiment contains silver nanowires obtained by the above production method. The content of silver nanowires in the ink is preferably large from the viewpoint of improving the conductivity of the pattern formed by the ink, but has an upper limit from the viewpoint of suppressing optical properties and aggregation, and is 0.05 to 60. % By mass is preferable, and 0.1 to 30% by mass is more preferable. In particular, when used as a transparent conductive film, it is preferably 0.05 to 10% by mass, more preferably 0.1 to 5% by mass in consideration of light transmittance.
　また、本実施形態のインクに含まれる溶媒は特に限定されないが、例えば、水；メタノール、エタノール、１－プロパノール、２－プロパノール、１－ブタノール、２－ブタノール等のアルコール系溶剤；アセトン、メチルエチルケトン、メチルイソブチルケトン等のケトン系溶剤；エチレングリコール、ジエチレングリコール、プロピレングリコール、１，３－プロパンジオール等のアルキレングリコール系溶剤；アルキレングリコールのアルキルエーテル系、ターピネオール、トルエン、ヘキサン等の炭化水素系溶剤が挙げられる。これらは、１種単独で使用してもよいし、２種以上を併用してもよい。 The solvent contained in the ink of the present embodiment is not particularly limited. For example, water; alcohol solvents such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol; acetone, methyl ethyl ketone, Ketone solvents such as methyl isobutyl ketone; alkylene glycol solvents such as ethylene glycol, diethylene glycol, propylene glycol, and 1,3-propanediol; hydrocarbon solvents such as alkyl ethers of alkylene glycol, terpineol, toluene, and hexane It is done. These may be used individually by 1 type and may use 2 or more types together.
　また、本実施形態のインクに加える溶媒として、水、低級アルコール系の溶媒を使用する場合にはポリ（Ｎ－ビニルホルムアミド）、ポリ（Ｎ－ビニルアセトアミド）またはポリ（Ｎ－ビニルプロピオンアミド）を、他の有機溶媒（より疎水的な）を使用する場合には、ポリ－Ｎ－ビニルピロリドン、ポリ－Ｎ－ビニルカプロラクタム、ポリビニル（Ｎ－メチル）アセトアミド等を、添加することがインク中の銀ナノワイヤーの分散性の点で好適である。これらの添加量は特に限定されないが、銀ナノワイヤー１００質量部に対し、通常０．０１～１０質量部程度であり、好ましくは０．０１～１質量部である。量があまりに多いと低抵抗化が難しく、あまりに少ないと添加する効果を発現しない。これらはインク中の銀ナノワイヤーの分散性を保持するとともに、バインダー樹脂としての機能を備える。なお、上記以外の公知のバインダー樹脂成分（ポリウレタン樹脂、セルロース系樹脂、ポリアセタール樹脂、ポリアルキレングリコール樹脂等）を配合することもできる。 In addition, when water or a lower alcohol solvent is used as a solvent to be added to the ink of the present embodiment, poly (N-vinylformamide), poly (N-vinylacetamide) or poly (N-vinylpropionamide) is used. When other organic solvents (more hydrophobic) are used, it is possible to add poly-N-vinyl pyrrolidone, poly-N-vinyl caprolactam, polyvinyl (N-methyl) acetamide, etc. It is suitable in terms of dispersibility of nanowires. The amount of these added is not particularly limited, but is usually about 0.01 to 10 parts by mass, preferably 0.01 to 1 part by mass with respect to 100 parts by mass of silver nanowires. If the amount is too large, it is difficult to reduce the resistance, and if the amount is too small, the effect of adding is not expressed. These hold | maintain the dispersibility of the silver nanowire in an ink, and are provided with the function as binder resin. In addition, well-known binder resin components (polyurethane resin, cellulose resin, polyacetal resin, polyalkylene glycol resin, etc.) other than the above can also be blended.
　なお、本実施形態のインクには、必要に応じて、上記以外の各種の添加剤等（例えば、界面活性剤、重合性化合物、重合体、酸化防止剤、腐食防止剤、粘度調整剤、防腐剤）を含有することができる。 The ink of the present embodiment includes various additives other than those described above (for example, surfactants, polymerizable compounds, polymers, antioxidants, corrosion inhibitors, viscosity modifiers, antiseptics, etc.) Agent).
　また、本実施形態のインクを印刷する基材は特に限定されるものではなく、樹脂、ガラス、セラミック、紙等の絶縁性材料、半導体材料または金属等の導体が挙げられる。これらのうち、上記樹脂基材としては、例えば、ポリエチレンテレフタレート基材、トリアセチルセルロース基材、ポリエチレンナフタレート基材、ポリカーボネート基材、ポリエステル基材、アクリロニトリル－ブタジエン－スチレン基材、ポリアクリル基材、ポリスチレン基材、ポリウレタン基材、エポキシ樹脂基材、ポリ塩化ビニル系基材、ポリアミド系基材等が挙げられる。 Further, the substrate on which the ink of the present embodiment is printed is not particularly limited, and examples thereof include insulating materials such as resin, glass, ceramic, and paper, semiconductor materials, and conductors such as metal. Among these, examples of the resin substrate include a polyethylene terephthalate substrate, a triacetyl cellulose substrate, a polyethylene naphthalate substrate, a polycarbonate substrate, a polyester substrate, an acrylonitrile-butadiene-styrene substrate, and a polyacryl substrate. Polystyrene base, polyurethane base, epoxy resin base, polyvinyl chloride base, polyamide base and the like.
　以下、実施例を挙げて本発明を詳細に説明するが、本発明はこれら実施例に限定されるものではない。 Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.
　実施例における各分析条件は以下に示すとおりである。 Each analysis condition in the examples is as shown below.
＜分子量測定＞
　重量平均分子量Ｍｗの測定にはゲルパーミエーションクロマトグラフィー（以下ＧＰＣと省略する）を用い、プルラン（標準試料）に換算した値で求めた。なおＧＰＣの測定条件は以下のとおりである。 <Molecular weight measurement>
For the measurement of the weight average molecular weight Mw, gel permeation chromatography (hereinafter abbreviated as GPC) was used, and it was obtained as a value converted to pullulan (standard sample). The measurement conditions for GPC are as follows.
　測定装置　　　　：Ｓｈｏｄｅｘ製　ＨＰＬＣ
　溶離液　　　　　：蒸留水
　検出器　　　　　：ｓｈｏｄｅｘ　ＲＩ－２０１Ｉ
　ポンプ　　　　　：ＳＨＩＭＡＤＺＵ　ＬＣ－２０ＡＤ
　カラムオーブン　：ＳＨＯＤＥＸ　ＡＯ－３０Ｃ
　解析装置　　　　：ＳＨＩＭＡＺＵ　ＳＩＣ　４８０II　Ｄｅｔａ　Ｓｔａｔｉｏｎ
　ポンプ流速　　　：０．７ｍＬ／ｍｉｎ
　カラム　　　　　：Ｓｈｏｄｅｘ　ＧＰＣ　ＳＢ－８０６　ＨＱ　２本
　カラム温度　　　：４０℃
　試料濃度　　　　：０．２質量％
　注入量　　　　　：２００μＬ Measuring apparatus: HPLC manufactured by Shodex
Eluent: Distilled water Detector: shodex RI-201I
Pump: SHIMADZU LC-20AD
Column oven: SHODEX AO-30C
Analysis device: SHIMAZU SIC 480II Data Station
Pump flow rate: 0.7 mL / min
Column: 2 Shodex GPC SB-806 HQ Column temperature: 40 ° C
Sample concentration: 0.2% by mass
Injection volume: 200 μL
＜銀ナノワイヤーの形状の観測＞
　銀ナノワイヤーの形状（長さ・直径）は、株式会社日立ハイテクノロジーズ製超高分解能電界放出形走査電子顕微鏡ＳＵ８０２０（加速電圧３～１０ｋＶ）を用いて１００本のナノワイヤーの径を観測した。 <Observation of silver nanowire shape>
The shape (length / diameter) of the silver nanowires was determined by observing the diameter of 100 nanowires using an ultra high resolution field emission scanning electron microscope SU8020 (acceleration voltage 3 to 10 kV) manufactured by Hitachi High-Technologies Corporation.
＜熱重量分析＞
　精製サンプルの熱重量分析はＮＥＴＺＳＣＨ社製ＴＧ／ＤＴＡを用いて行った。 <Thermogravimetric analysis>
Thermogravimetric analysis of the purified sample was performed using TG / DTA manufactured by NETZSCH.
合成例１　ポリ（Ｎ－ビニルホルムアミド）の合成
　１Ｌ三口フラスコにＮ－ビニルホルムアミド（東京化成工業（株）製、１００ｇ、１．４１ｍｏｌ）および純水４００ｇを加え完全に溶解させた後、気相と液相を窒素ガスで２時間置換（気相は窒素ガスフロー、液相は窒素ガスバブリング）した。液相の窒素ガス置換のみを止め、気相を窒素ガスフローさせたまま６０℃まで昇温した。重合開始剤としてＶ－５０（和光純薬工業（株）製、０．９ｇ、３．３２ｍｍｏｌ）を純水１０ｇに溶解させ、シリンジを用いて系中に加えた。６０℃で６時間反応を継続した後、反応液をバットにあけオーブンに入れて、常圧で乾燥具合を見ながら突沸しないように１２０℃までゆっくり昇温し、最終的に真空オーブンに移して２４時間減圧乾燥させることでポリ（Ｎ－ビニルホルムアミド）を白色固体として７７ｇ得た。ＧＰＣによる分子量測定の結果、Ｍｗは１６００００であった。 Synthesis Example 1 Synthesis of poly (N-vinylformamide) N-vinylformamide (Tokyo Chemical Industry Co., Ltd., 100 g, 1.41 mol) and 400 g of pure water were added to a 1 L three-necked flask and completely dissolved. The liquid phase was replaced with nitrogen gas for 2 hours (nitrogen gas flow for the gas phase and nitrogen gas bubbling for the liquid phase). Only the substitution of nitrogen gas in the liquid phase was stopped, and the temperature was raised to 60 ° C. with the gas phase flowing in the nitrogen gas flow. As a polymerization initiator, V-50 (manufactured by Wako Pure Chemical Industries, Ltd., 0.9 g, 3.32 mmol) was dissolved in 10 g of pure water and added to the system using a syringe. After the reaction is continued for 6 hours at 60 ° C, the reaction solution is put into a vat and placed in an oven. The temperature is slowly raised to 120 ° C while watching the drying condition at normal pressure, and finally transferred to a vacuum oven. By drying under reduced pressure for 24 hours, 77 g of poly (N-vinylformamide) was obtained as a white solid. As a result of molecular weight measurement by GPC, Mw was 160000.
実施例１　銀ナノワイヤーの製造
　東京理化機械（株）製のパーソナル有機合成装置ＰＰＳ－ＣＴＲＬ１用反応容器に、プロピレングリコール２０ｇ、合成例１で合成したポリ（Ｎ－ビニルホルムアミド）０．６８ｇ（９．６ｍｍｏｌ）を仕込み、６０℃で１時間撹拌することで完全に溶解させた。バイアル瓶に硝酸銀（和光純薬工業（株）製）０．３ｇ、プロピレングリコール４ｇを入れ室温で撹拌することで完全に溶解させた。塩化テトラブチルアンモニウム（ＡＣＲＯＳ社製）の１質量％プロピレングリコール溶液０．７３８ｇ（２６．６μｍｏｌ）を反応容器に添加した後、反応容器上部に滴下漏斗を設置して先に調製した硝酸銀溶液を投入した。枝管より窒素ガスを３００ｍＬ／ｍｉｎの流量で５分間流して系を窒素ガス置換した。枝管の窒素ガスを止め温度計を設置し、内温が１３０℃となるまで昇温した。内温１３０℃にて６分間かけて滴下漏斗の内容物を滴下し、さらに１３０℃で１時間反応を継続した。反応混合物をエタノールで５倍に希釈し、遠心分離機を用いて６０００ｒｐｍの回転数で５分間処理することで銀ナノワイヤーを沈降させた。エタノール５０ｇを添加し６０００ｒｐｍで５分間処理する操作をさらに２回行い系中に残存するポリ（Ｎ－ビニルホルムアミド）及び溶媒を洗浄した。得られたワイヤーについて電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）を用いてワイヤーの形状を測定し。得られた銀ナノワイヤーの形状を表１に、電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を図１に示す。 Example 1 Production of Silver Nanowire In a reaction vessel for personal organic synthesizer PPS-CTRL1 manufactured by Tokyo Rika Kikai Co., Ltd., 20 g of propylene glycol and 0.68 g of poly (N-vinylformamide) synthesized in Synthesis Example 1 (9 .6 mmol) was added and stirred at 60 ° C. for 1 hour for complete dissolution. In a vial, 0.3 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 4 g of propylene glycol were added and completely dissolved by stirring at room temperature. After adding 0.738 g (26.6 μmol) of a 1% by mass propylene glycol solution of tetrabutylammonium chloride (ACROS) to the reaction vessel, a dropping funnel was installed at the top of the reaction vessel and the silver nitrate solution prepared earlier was added. did. Nitrogen gas was passed through the branch pipe at a flow rate of 300 mL / min for 5 minutes to replace the system with nitrogen gas. The nitrogen gas in the branch pipe was stopped, a thermometer was installed, and the temperature was raised until the internal temperature reached 130 ° C. The contents of the dropping funnel were dropped over 6 minutes at an internal temperature of 130 ° C., and the reaction was further continued at 130 ° C. for 1 hour. The reaction mixture was diluted 5-fold with ethanol, and silver nanowires were precipitated by treating with a centrifuge at a rotation speed of 6000 rpm for 5 minutes. The operation of adding 50 g of ethanol and treating at 6000 rpm for 5 minutes was further performed twice to wash the poly (N-vinylformamide) and the solvent remaining in the system. The shape of the obtained wire was measured using a field emission scanning electron microscope (FE-SEM). The shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
実施例２　銀ナノワイヤーの製造
　合成例１で合成したポリ（Ｎ－ビニルホルムアミド）０．６８ｇ（９．６ｍｍｏｌ）の代わりにポリ（Ｎ－ビニルアセトアミド）（以下ＰＮＶＡと略する昭和電工（株）製）ＧＰ１９１－４０５（Ｍｗ：１３００００、０．８１７ｇ、９．６ｍｍｏｌ）を用い、１３０℃での反応時間を１時間から２０分間に変更した以外は実施例１同様の条件により銀ナノワイヤーを得て、ワイヤーの形状を測定した。得られた銀ナノワイヤーの形状を表１に、電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を図２に示す。 Example 2 Production of Silver Nanowire Instead of 0.68 g (9.6 mmol) of poly (N-vinylformamide) synthesized in Synthesis Example 1, poly (N-vinylacetamide) (hereinafter abbreviated as PNVA) A silver nanowire was obtained under the same conditions as in Example 1 except that GP191-405 (Mw: 130000, 0.817 g, 9.6 mmol) was used and the reaction time at 130 ° C. was changed from 1 hour to 20 minutes. Then, the shape of the wire was measured. The shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
実施例３
　ＰＮＶＡとしてＧＰ１９１－４０５（Ｍｗ：２６００００）を用いた以外は実施例２と同様の条件により銀ナノワイヤーを得て、ワイヤーの形状を測定した。得られた銀ナノワイヤーの形状を表１に、電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を図３に示す。 Example 3
A silver nanowire was obtained under the same conditions as in Example 2 except that GP191-405 (Mw: 260000) was used as PNVA, and the shape of the wire was measured. The shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
実施例４
　ＰＮＶＡとしてＧＥ１９１－２０５（Ｍｗ：１８００００）を用いた以外は実施例２と同様の条件により銀ナノワイヤーを得て、ワイヤーの形状を測定した。得られた銀ナノワイヤーの形状を表１に、電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を図４に示す。 Example 4
A silver nanowire was obtained under the same conditions as in Example 2 except that GE191-205 (Mw: 180000) was used as PNVA, and the shape of the wire was measured. The shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
実施例５
　合成例１で合成したポリ（Ｎ－ビニルホルムアミド）０．６８ｇ（９．６ｍｍｏｌ）の代わりにＮ－ビニルアセトアミドとアクリロニトリルの９対１共重合体（以下ＮＶＡ／ＡＮと略する昭和電工（株）製、Ｍｗ：１５００００）０．８２ｇ（９．６ｍｍｏｌ）を用いた以外は実施例１同様の条件により銀ナノワイヤーを得て、ワイヤーの形状を測定した。得られた銀ナノワイヤーの形状を表１に、電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を図５に示す。 Example 5
9-to-1 copolymer of N-vinylacetamide and acrylonitrile instead of 0.68 g (9.6 mmol) of poly (N-vinylformamide) synthesized in Synthesis Example 1 (hereinafter referred to as NVA / AN) Silver nanowires were obtained under the same conditions as in Example 1 except that 0.82 g (9.6 mmol) was used, and the shape of the wires was measured. The shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
実施例６
　合成例１で合成したポリ（Ｎ－ビニルホルムアミド）０．６８ｇ（９．６ｍｍｏｌ）の代わりにＮ－ビニルアセトアミドとメタクリル酸メチルの９対１共重合体（以下ＮＶＡ／ＭＭＡと略する昭和電工（株）製、Ｍｗ：１５００００）０．８２ｇ（９．６ｍｍｏｌ）を用いた以外は実施例１同様の条件により銀ナノワイヤーを得て、ワイヤーの形状を測定した。得られた銀ナノワイヤーの形状を表１に、電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を図６に示す。 Example 6
Instead of 0.68 g (9.6 mmol) of poly (N-vinylformamide) synthesized in Synthesis Example 1, a 9-to-1 copolymer of N-vinylacetamide and methyl methacrylate (hereinafter referred to as NVA / MMA) Silver nanowires were obtained under the same conditions as in Example 1 except that 0.82 g (9.6 mmol) manufactured by Mw: 150,000) was used, and the shape of the wires was measured. The shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
実施例７
　東京理化機械（株）製のパーソナル有機合成装置ＰＰＳ－ＣＴＲＬ１用反応容器に、プロピレングリコール２０ｇ、ＰＮＶＡ ＧＰ１９１－４０５（Ｍｗ：１３００００）０．５４ｇ（６．４ｍｍｏｌ）を仕込み、６０℃で１時間撹拌することで完全に溶解させた。バイアル瓶に硝酸銀（和光純薬工業（株）製）０．０７５ｇ、プロピレングリコール１ｇを入れ室温で撹拌することで完全に溶解させた。塩化テトラブチルアンモニウム（ＡＣＲＯＳ社製）の１質量％プロピレングリコール溶液０．７３８ｇ（２６．６μｍｏｌ）を反応容器に添加した後、反応容器上部に滴下漏斗を設置して先に調製した硝酸銀溶液を投入した。枝管より窒素ガスを３００ｍＬ／ｍｉｎの流量で流して系を窒素ガス置換しつつ、内温が１３０℃となるまで昇温した。内温１３０℃にて１分間かけて滴下漏斗の内容物を滴下し、さらに１３０℃で１時間反応を継続した。反応混合物をエタノールで５倍に希釈し、遠心分離機を用いて６０００ｒｐｍの回転数で５分間処理することで銀ナノワイヤーを沈降させた。エタノール５０ｇを添加し６０００ｒｐｍで５分間処理する操作をさらに２回行い系中に残存するＰＮＶＡ及び溶媒を洗浄した。得られたワイヤーについて電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）を用いてワイヤーの形状を測定した。得られた銀ナノワイヤーの形状を表１に、電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）画像を図７に示す。 Example 7
Propylene glycol 20 g and PNVA GP191-405 (Mw: 130000) 0.54 g (6.4 mmol) were placed in a reaction vessel for the personal organic synthesizer PPS-CTRL1 manufactured by Tokyo Rika Kikai Co., Ltd., and stirred at 60 ° C. for 1 hour. To completely dissolve. 0.075 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 1 g of propylene glycol were placed in a vial and stirred completely at room temperature for complete dissolution. After adding 0.738 g (26.6 μmol) of a 1% by mass propylene glycol solution of tetrabutylammonium chloride (ACROS) to the reaction vessel, a dropping funnel was installed at the top of the reaction vessel and the silver nitrate solution prepared earlier was added. did. Nitrogen gas was supplied from the branch pipe at a flow rate of 300 mL / min to replace the system with nitrogen gas, and the temperature was increased until the internal temperature reached 130 ° C. The contents of the dropping funnel were added dropwise at an internal temperature of 130 ° C. over 1 minute, and the reaction was further continued at 130 ° C. for 1 hour. The reaction mixture was diluted 5-fold with ethanol, and silver nanowires were precipitated by treating with a centrifuge at a rotation speed of 6000 rpm for 5 minutes. The operation of adding 50 g of ethanol and treating at 6000 rpm for 5 minutes was further performed twice to wash away PNVA and the solvent remaining in the system. The shape of the wire was measured using a field emission scanning electron microscope (FE-SEM). The shape of the obtained silver nanowire is shown in Table 1, and a field emission scanning electron microscope (FE-SEM) image is shown in FIG.
実施例８
　１Ｌ四つ口フラスコ（メカニカルスターラー、滴下漏斗、還流管、温度計）にプロピレングリコール２００ｇ、ＰＮＶＡ　ＧＰ１９１－４０５（Ｍｗ：１３００００、８．１７ｇ、９６ｍｍｏｌ）を仕込み、６０℃で１時間撹拌することで完全に溶解させた。ビーカーに硝酸銀（和光純薬工業（株）製）３ｇ、プロピレングリコール４０ｇを入れ室温で撹拌することで完全に溶解させた。塩化テトラブチルアンモニウム（ＡＣＲＯＳ社製）の１質量％プロピレングリコール溶液７．３８ｇ（０．２７ｍｍｏｌ）をフラスコに添加した後、滴下漏斗へ先に作製した硝酸銀溶液を投入した。滴下漏斗上部より窒素ガスを３００ｍＬ／ｍｉｎの流量で２０分間流して系を窒素ガス置換した。枝管の窒素ガスを止め、内温が１３０℃となるまで昇温した。内温１３０℃にて３０分間かけて滴下漏斗の内容物を滴下し、さらに１３０℃で６０分反応を継続した。 Example 8
A 1 L four-necked flask (mechanical stirrer, dropping funnel, reflux tube, thermometer) was charged with 200 g of propylene glycol and PNVA GP191-405 (Mw: 130000, 8.17 g, 96 mmol) and stirred at 60 ° C. for 1 hour. It was completely dissolved. In a beaker, 3 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 40 g of propylene glycol were placed and stirred at room temperature for complete dissolution. After adding 7.38 g (0.27 mmol) of a 1% by mass propylene glycol solution of tetrabutylammonium chloride (manufactured by ACROS) to the flask, the previously prepared silver nitrate solution was charged into the dropping funnel. Nitrogen gas was supplied from the upper part of the dropping funnel at a flow rate of 300 mL / min for 20 minutes to replace the system with nitrogen gas. The nitrogen gas in the branch pipe was stopped and the temperature was raised until the internal temperature reached 130 ° C. The contents of the dropping funnel were added dropwise at an internal temperature of 130 ° C. over 30 minutes, and the reaction was further continued at 130 ° C. for 60 minutes.
　反応混合物をメタノールで４倍に希釈し、クロスフローろ過装置（ＮＧＫフィルテック株式会社製セルフィト卓上試験機、細孔径２μｍ）を用いて洗浄をおこなった。洗浄条件およびＴＧ／ＤＴＡによる分析結果を表２に示す。 The reaction mixture was diluted 4 times with methanol, and washed using a cross flow filtration apparatus (NGK Filtech Corp., Selfif tabletop tester, pore size 2 μm). Table 2 shows the washing conditions and the analysis results by TG / DTA.
比較例１
　ＰＮＶＡとしてＧＥ１９１－１０４（Ｍｗ：３０００００）を用いた以外は実施例２と同様の条件により銀ナノワイヤーの製造工程を実施した。生成物の形状を表１に示す。 Comparative Example 1
A silver nanowire manufacturing process was performed under the same conditions as in Example 2 except that GE191-104 (Mw: 300,000) was used as PNVA. The shape of the product is shown in Table 1.
　表１に示されるように、本比較例における生成物の形状は球状となり、銀ナノワイヤーは製造できなかった。これは、ＰＮＶＡの重量平均分子量Ｍｗが３０００００と高かったためと考えられる。 As shown in Table 1, the shape of the product in this comparative example was spherical, and silver nanowires could not be produced. This is probably because the weight average molecular weight Mw of PNVA was as high as 300000.
比較例２
　ＰＮＶＡとしてＧＥ１９１－４０５Ｐ（Ｍｗ：８００００）を用いた以外は実施例２と同条件にて銀ナノワイヤーの製造工程を実施した。生成物の形状を表１に示す。 Comparative Example 2
A silver nanowire manufacturing process was performed under the same conditions as in Example 2 except that GE191-405P (Mw: 80000) was used as PNVA. The shape of the product is shown in Table 1.
　表１に示されるように、本比較例における生成物の形状は微粒状となり、銀ナノワイヤーは製造できなかった。これは、ＰＮＶＡの重量平均分子量Ｍｗが８００００と低かったためと考えられる。 As shown in Table 1, the shape of the product in this comparative example was fine, and silver nanowires could not be produced. This is probably because the weight average molecular weight Mw of PNVA was as low as 80000.
比較例３
　１Ｌ四つ口フラスコ（メカニカルスターラー、滴下漏斗、還流管、温度計）にプロピレングリコール２００ｇ、ポリビニルピロリドン　Ｋ－９０（以下ＰＶＰ　Ｋ－９０と省略する和光純薬工業（株）製）１０．７ｇ（９６ｍｍｏｌ）を仕込み、６０℃で１時間撹拌することで完全に溶解させた。ビーカーに硝酸銀（和光純薬工業（株）製）３ｇ、プロピレングリコール８０ｇを入れ室温で撹拌することで完全に溶解させた。塩化テトラブチルアンモニウム（ＡＣＲＯＳ社製）の１質量％プロピレングリコール溶液７．３８ｇ（０．２７ｍｍｏｌ）をフラスコに添加した後、滴下漏斗へ先に作製した硝酸銀溶液を投入した。滴下漏斗上部より窒素ガスを３００ｍＬ／ｍｉｎの流量で２０分間流して系を窒素ガス置換した。枝管の窒素ガスを止め、内温が１６０℃となるまで昇温した。内温１６０℃にて３０分間かけて滴下漏斗の内容物を滴下し、さらに１６０℃で６０分反応を継続した。 Comparative Example 3
1 L four-necked flask (mechanical stirrer, dropping funnel, reflux tube, thermometer) with propylene glycol 200 g, polyvinylpyrrolidone K-90 (hereinafter abbreviated as PVP K-90, manufactured by Wako Pure Chemical Industries, Ltd.) 10.7 g ( 96 mmol) was added and stirred at 60 ° C. for 1 hour for complete dissolution. 3 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 80 g of propylene glycol were placed in a beaker and stirred at room temperature for complete dissolution. After adding 7.38 g (0.27 mmol) of a 1% by mass propylene glycol solution of tetrabutylammonium chloride (manufactured by ACROS) to the flask, the previously prepared silver nitrate solution was charged into the dropping funnel. Nitrogen gas was supplied from the upper part of the dropping funnel at a flow rate of 300 mL / min for 20 minutes to replace the system with nitrogen gas. The nitrogen gas in the branch pipe was stopped and the temperature was raised until the internal temperature reached 160 ° C. The contents of the dropping funnel were added dropwise at an internal temperature of 160 ° C. over 30 minutes, and the reaction was further continued at 160 ° C. for 60 minutes.
　反応混合物をメタノールで４倍に希釈し、クロスフローろ過装置（ＮＧＫフィルテック株式会社製セルフィト卓上試験機、細孔径２μｍ）を用いて洗浄をおこなった。洗浄条件およびＴＧ／ＤＴＡによる分析結果を表２に示す。 The reaction mixture was diluted 4 times with methanol, and washed using a cross flow filtration apparatus (NGK Filtech Corp., Selfif tabletop tester, pore size 2 μm). Table 2 shows the washing conditions and the analysis results by TG / DTA.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　クロスフローろ過によるろ過洗浄工程を６回繰り返した後、ＰＮＶＡを用いた実施例８では樹脂の残存量が０．０５質量％であるのに対し、ＰＶＰを用いた比較例３では０．２９質量％と多くの樹脂が洗浄できず残存していることが分かる。
  After the filtration washing process by cross flow filtration was repeated 6 times, in Example 8 using PNVA, the residual amount of resin was 0.05% by mass, whereas in Comparative Example 3 using PVP, 0.29% by mass. It can be seen that a large amount of resin cannot be cleaned.

Claims (10)

  1. 　Ｒ－ＣＯＮＨＲ’（Ｒは水素原子または炭素原子数が１～３のアルキル基、Ｒ’は炭素－炭素二重結合を有する炭素原子数が２または３のアルケニル基）で表される第二級アミド化合物をモノマー単位に含む重量平均分子量が１０００００～２８００００の重合体および還元剤の存在下で、銀化合物を加熱する工程を含む銀ナノワイヤーの製造方法。 A secondary group represented by R—CONHR ′ (wherein R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ′ is an alkenyl group having 2 or 3 carbon atoms having a carbon-carbon double bond) A method for producing silver nanowires, comprising a step of heating a silver compound in the presence of a polymer containing an amide compound in a monomer unit and having a weight average molecular weight of 100,000 to 280000 and a reducing agent.
  2. 　前記重合体が、ポリ（Ｎ－ビニルホルムアミド）、ポリ（Ｎ－ビニルアセトアミド）またはポリ（Ｎ－ビニルプロピオンアミド）から選ばれる１種以上の重合体である、請求項１に記載の銀ナノワイヤーの製造方法。 The silver nanowire according to claim 1, wherein the polymer is at least one polymer selected from poly (N-vinylformamide), poly (N-vinylacetamide), or poly (N-vinylpropionamide). Manufacturing method.
  3. 　前記銀化合物が、硝酸銀、ヘキサフルオロホスフェート銀、硼弗化銀、過塩素酸銀、塩素酸銀、塩化銀、臭化銀、フッ化銀、炭酸銀、硫酸銀、酢酸銀、トリフルオロ酢酸銀のいずれかである請求項１または２に記載の銀ナノワイヤーの製造方法。 The silver compound is silver nitrate, hexafluorophosphate silver, silver borofluoride, silver perchlorate, silver chlorate, silver chloride, silver bromide, silver fluoride, silver carbonate, silver sulfate, silver acetate, silver trifluoroacetate The method for producing silver nanowires according to claim 1 or 2, wherein the silver nanowires are any one of the above.
  4. 　ポリオールを前記還元剤および／または溶媒として含む、請求項１～３のいずれか一項に記載の銀ナノワイヤーの製造方法。 The method for producing silver nanowires according to any one of claims 1 to 3, comprising a polyol as the reducing agent and / or solvent.
  5. 　前記ポリオールが、炭素原子数２～６であり、２～６価のアルコール化合物である請求項４に記載の銀ナノワイヤーの製造方法。 The method for producing silver nanowires according to claim 4, wherein the polyol is a divalent to hexavalent alcohol compound having 2 to 6 carbon atoms.
  6. 　前記銀化合物１００質量部に対して前記ポリオールを１００００～１０００００質量部用いる、請求項４または５に記載の銀ナノワイヤーの製造方法。 The method for producing silver nanowires according to claim 4 or 5, wherein 10,000 to 100,000 parts by mass of the polyol is used with respect to 100 parts by mass of the silver compound.
  7. 　４級アンモニウム塩をさらに加える、請求項１～６のいずれか一項に記載の銀ナノワイヤーの製造方法。 The method for producing a silver nanowire according to any one of claims 1 to 6, wherein a quaternary ammonium salt is further added.
  8. 　請求項１～７のいずれか一項に記載の銀ナノワイヤーの製造方法で得られた銀ナノワイヤーの表面に付着した前記重合体を除去する工程をさらに含む銀ナノワイヤーの製造方法。 A method for producing silver nanowires, further comprising a step of removing the polymer attached to the surface of the silver nanowires obtained by the method for producing silver nanowires according to any one of claims 1 to 7.
  9. 　請求項１～８のいずれか一項に記載の銀ナノワイヤーの製造方法で得られた銀ナノワイヤー。 A silver nanowire obtained by the method for producing a silver nanowire according to any one of claims 1 to 8.
  10. 　請求項９に記載の銀ナノワイヤーを含有するインク。
          An ink containing the silver nanowire according to claim 9.
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