TWI682406B - Production method of silver nanowire, silver nanowire produced by production method and ink comprising silver nanowire - Google Patents

Abstract

An object of the present invention is to provide a method for manufacturing a silver nanowire that can easily wash the silver nanowire after manufacturing, a silver nanowire obtained by the method, and an ink containing the silver nanowire.

The solution of the present invention is R-CONHR' contained in the monomer unit (R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R'is an alkene having 2 or 3 carbon atoms with a carbon-carbon double bond In the presence of a polymer having a weight average molecular weight of 100,000 to 280,000 represented by a second-stage amide compound represented by a base) and a reducing agent, silver nanowires are manufactured by heating the silver compound. The polymer of the above compound is one or more polymers selected from poly(N-vinylformamide), poly(N-vinylacetamide), or poly(N-vinylacetamide).

Description

Manufacturing method of silver nanowire, silver nanowire obtained by this method, and ink containing silver nanowire

The invention relates to a method for manufacturing silver nanowire, a silver nanowire obtained by the method, and an ink containing the silver nanowire.

In recent years, silver nanowires have been attracting attention as a raw material for high transparency and high conductivity thin films used to replace ITO (indium tin oxide) films used in transparent electrodes such as touch panels. The silver nanowire is produced by heating a silver compound in the presence of a general polyol such as polyvinylpyrrolidone and ethylene glycol (Patent Document 1, Non-Patent Document 1).

However, although polyvinylpyrrolidone is soluble in glycol water, there are many cases where chloride salts or other inorganic salts coexist in order to control the wire diameter of the silver nanowire during the above reaction (Patent Document 2). Reduce the solubility of glycol or water in polyvinylpyrrolidone. Therefore, in such a state, polyvinylpyrrolidone is deposited on the surface of the grown silver nanowires, and it is difficult to remove by washing after the reaction. Use so If the silver nanowire of polyvinylpyrrolidone remains, if the silver nanowire is not cleaned with an excessive amount of alcohol, there is a disadvantage that the polyvinylpyrrolidone on the silver nanowire cannot be removed. Although when printing silver nanowires, water, alcohol, organic solvents, etc. must be used according to the printed substrate. When polyvinylpyrrolidone remains on the surface of the silver nanowires, the resistance of the conductive film is reduced, not only to remove the silver The strong energy of polyvinylpyrrolidone on the surface of the nanowire is also insufficient for the dispersion medium, that is, especially for the aqueous dispersion medium, and a dispersant must be added.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] US Patent No. 7,585,349

[Patent Document 2] US Patent No. 8,512,438

[Non-Patent Literature]

[Non-Patent Document 1] Ducamp-Sanguesa, et al., J. Solid State Chem., 1992, 100, 272

Therefore, an object of the present invention is to provide a method for manufacturing a silver nanowire that can easily wash the silver nanowire after manufacturing, a silver nanowire obtained by the method, and an ink containing the silver nanowire.

In order to achieve the above object, one embodiment of the present invention is a method for manufacturing silver nanowires, characterized by R-CONHR' (R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R' It is a step of heating the silver compound in the presence of a polymer having a weight average molecular weight of 100,000 to 280,000 and a reducing agent of the second-stage amide compound having a carbon-carbon double bond and an alkenyl group having a carbon number of 2 or 3).

The polymer of the above compound is one or more polymers selected from poly(N-vinylformamide), poly(N-vinylacetamide), or poly(N-vinylacetamide).

In addition, the silver compound is silver nitrate, silver hexafluorophosphate, silver fluoride borate, silver perchlorate, silver chlorate, silver chloride, silver bromide, silver fluoride, silver carbonate, silver sulfate, silver acetate, trifluoro Any one of silver acetate is more suitable.

It is appropriate to include a polyhydric alcohol as the reducing agent and/or solvent. In addition, a polyol-based alcohol compound having 2 to 6 carbon atoms and 2 to 6 valences is more suitable.

Moreover, the manufacturing method of the said silver nanowire is suitable to use 10,000-100,000 mass parts of polyols with respect to 100 mass parts of silver compounds.

In addition, the above-mentioned method of manufacturing silver nanowires is more appropriate to add a fourth-grade ammonia salt.

In addition, the method for manufacturing the silver nanowire further includes the step of removing the polymer adsorbed on the surface of the obtained silver nanowire.

In addition, another embodiment of the present invention is a silver nanowire, which is characterized by being obtained by any of the above-mentioned methods for manufacturing silver nanowire.

In addition, still another embodiment of the present invention is an ink characterized by including the aforementioned silver nanowire.

According to the present invention, the washing step when manufacturing silver nanowires can be greatly simplified.

[Fig. 1] A diagram showing a field emission scanning electron microscope (FE-SEM) image of silver nanowires obtained in Example 1.

[Fig. 2] A diagram showing a field emission scanning electron microscope (FE-SEM) image of silver nanowires obtained in Example 2.

[Fig. 3] A diagram showing a field emission scanning electron microscope (FE-SEM) image of silver nanowires obtained in Example 3.

[Fig. 4] A diagram showing a field emission scanning electron microscope (FE-SEM) image of silver nanowires obtained in Example 4.

[Fig. 5] A diagram showing a field emission scanning electron microscope (FE-SEM) image of silver nanowires obtained in Example 5.

[Fig. 6] A diagram showing a field emission scanning electron microscope (FE-SEM) image of silver nanowires obtained in Example 6.

[Figure 7] Field emission scan of the silver nanowire obtained in Example 7 Image of an electron microscope (FE-SEM) image.

Hereinafter, an embodiment for implementing the present invention (hereinafter referred to as an embodiment) will be described.

The manufacturing method of the silver nanowire of this embodiment is R-CONHR' (R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms) contained in the monomer unit, and R'represents the carbon number having a carbon-carbon double bond The alkenyl group represented by 2 or 3) includes the step of heating the silver compound in the presence of the polymer of the second-stage amide compound and the reducing agent. Silver nanowire means nanofibers with a diameter of silver of nanometer grade.

Examples of the silver compound include silver salts, which can be used alone or in combination of two or more. In addition, when an inorganic acid salt of an alkali metal described later is used, by using a silver compound that can be dissolved in a solvent in which the inorganic acid salt of the alkali metal is dissolved, the reaction can be performed uniformly.

Although the above-mentioned silver salt is roughly an inorganic salt and an organic salt, an inorganic salt is preferable from the viewpoint of easy industrial start.

Specific examples of silver compounds include silver nitrate (AgNO ₃ ), silver hexafluorophosphate (AgPF ₆ ), silver fluoride borate (AgBF ₄ ), silver perchlorate (AgClO ₄ ), silver chlorate (AgClO ₃ ), and chlorine Silver chloride (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 ), trifluoroacetic acid Silver (AgO ₂ CCF ₃ ), from the viewpoint of the production efficiency of silver nanowires and the shape of the silver nanowires to be obtained, silver nitrate, silver perchlorate, silver chlorate, silver fluoride, silver hexafluorophosphate , Silver fluoride borate and silver trifluoroacetate are preferred. From the viewpoint of solubility in solvents, silver nitrate, silver hexafluorophosphate, silver fluoride borate and silver acetate are more preferred. The silver concentration in the reaction solution is metallic silver. Although the range of 0.05 to 2% by mass is preferable, and the range of 0.06 to 1% by mass is more preferable, the range of 0.07 to 0.5% by mass is particularly preferable in order to obtain a fine-diameter silver nanowire. .

The polymer (polymer) of the second-stage amide compound contained in the monomer unit used in the present embodiment functions as a coating agent in the synthesis stage of the silver nanowire. The coating agent means a substance (ion, surfactant, etc.) adsorbed on a specific surface of the generated core, suppresses the growth rate of the surface, and controls the shape of the generated particles. By choosing the part of the silver nanowire that is adsorbed on the side of the nanowire, a slender nanowire can be obtained. The coating agent is summarized in the following non-patent literature, for example.

Xia,et al.Acc.Chem.Res.2007,40,1067. is Jin Xinxing, Journal of Japan Crystal Growth Society, 2010,37,No.4,281

Examples of the coating agent include R-CONHR' contained in the monomer unit (R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R'has a carbon-carbon double bond and has 2 or 3 carbon atoms. Alkenyl) represents a relatively hydrophilic polymer of the above-mentioned second-stage amide compound of derivatives of carboxylic acid formic acid, acetic acid, propionic acid, and butyric acid with a comparatively hydrophilic carbon number of 3 or less. Specific examples of R'include vinyl, isopropenyl, and allyl. Specific examples of the coating agent are poly(N-vinylformamide), poly(N-vinylacetamide), and poly(N-vinylacetamide). In the present embodiment, in the presence of one or more polymers selected from such polymers and a reducing agent, by heating the silver compound from The manufactured silver nanowire can easily wash the coating agent.

In addition, the above-mentioned polymer system is not only selected from a single polymer of poly(N-vinylformamide), poly(N-vinylacetamide) or poly(N-vinylacetamide) or as a polymer It is also possible to use a copolymer of the above-mentioned second-stage amide compound and other polymerizable monomers contained in the monomer unit. Examples of other polymerizable monomers include acrylonitrile, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, phenyl (meth)acrylate, acrylamide, N , N-dimethylacrylamide, etc. When using a copolymer with other polymerizable monomers, the second-stage amide monomer unit in the copolymer is preferably in the range of 20 to 95 mol%, and more preferably in the range of 30 to 90 mol%. However, these polymers are hydrogen atoms bonded to the nitrogen atom of the amide group, and have a high affinity with the (hydrophilic) reaction solvent described later, so the protective colloid is low, and it can be used to obtain silver nanowires from silver compounds. Limitation of the molecular weight range of polymers.

That is, when using such polymers, polymers having a weight average molecular weight in the range of 100,000 to 280,000 must be used, preferably 110,000 to 250,000, and more preferably 120,000 to 200,000. When the molecular weight is less than 100,000 hours, only fine-particle silver particles can be obtained, and even if the molecular weight exceeds 280,000, the molecular weight becomes too large and it is difficult to adsorb, and the proportion of fine-particle silver particles tends to increase.

Although the total use amount of the above-mentioned polymers is not particularly limited, it is usually about 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass relative to 1 part by mass of the silver compound. When it is lower than 0.5 parts by mass, it cannot effectively adsorb, and when it is more than 20 parts by mass, the viscosity of the reaction solution becomes Too high and not good.

In addition, the heating of the silver compound in the presence of the above-mentioned polymer can be performed in the presence of the above-mentioned polymer and an inorganic acid salt of an alkali metal. As such an alkali metal inorganic acid salt, alkali metal nitrate and alkali metal nitrite are preferable, and alkali metal nitrate is more preferable.

Specifically, potassium nitrate, sodium nitrate, potassium nitrite, sodium nitrite, etc. can be cited, and any of these can be used alone or in combination.

Although the total usage amount of the above-mentioned alkali metal inorganic acid salts is not particularly limited, it is usually about 0.05 to 2 molar equivalents relative to 1 mole of silver compound, preferably 0.1 to 1 molar equivalent.

In addition, when an inorganic acid salt of an alkali metal is used, an alkali metal halide can be used at the same time. 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; and the like. One can be used alone or in combination.

Although the total usage amount of the above-mentioned alkali metal halides is not particularly limited, it is usually about 1×10 ^-7 to 3×10 ^-1 molar equivalents relative to 1 mole of silver compound, preferably 1×10 ^-6 to 1 ×10 ^-2 molar equivalent. When the total usage amount of the alkali metal halide is less than 1×10 ⁻⁷ mol equivalent, it does not promote the selective growth of the shape of the silver nanowire and extremely reduces the yield of the wire. In addition, when the total amount of alkali metal halides exceeds 3×10 ⁻¹ molar equivalent, the production ratio of large and large silver particles increases, which extremely reduces the yield.

In addition, the fourth-stage ammonia salt can be used together with the polymer during the heating. As such fourth-level ammonia salts, tetramethylammonium chloride, Tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, hexadecyltrimethylammonium chloride and other quaternary ammonium chlorides or tetramethylammonium bromide, tetraethylammonium bromide Quaternary ammonium bromide such as ammonium, tetrapropylammonium bromide, tetrabutylammonium bromide, cetyltrimethylammonium bromide, etc., any of these can be used alone or in combination. From the viewpoint of the linear shape obtained in these, tetrabutylammonium chloride and tetrabutylammonium bromide are preferred.

Although the total amount of the above-mentioned fourth-grade ammonia salt is not particularly limited, it is usually about 0 to 1 mole equivalent, preferably 0 to 0.5 mole equivalent, relative to 1 mole of silver compound.

In addition, the above heating is performed in the presence of a reducing agent. The silver compound is precipitated by reducing the silver compound with a reducing agent. Although those having a well-known reducing action as a reducing agent can use, for example, hydrogen, hydrazine, sodium borohydride, lithium aluminum hydride, etc., those who can use both as solvents described later are preferred from the viewpoint of safety and economy.

The above heating must be performed in the state where the silver compound is dissolved or dispersed in the presence of the solvent. Examples of the solvent include polyhydric alcohols, water, and monovalent alcohols. From the viewpoint of obtaining a reduction effect, a solvent containing a polyhydric alcohol is preferred. Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, polyethylene glycol 300, propylene glycol, dipropylene glycol, 1,3-propanediol, and 2-methyl-1,3. -Divalent alcohols such as propylene glycol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol; glycerin, etc. Trivalent alcohols; pentaerythritol, diglycerin, hexavalent alcohols such as divalent methyl propane tetravalent alcohols, sorbitol, etc., any of these can be used alone or in combination. When the carbon number is 2~6, the 2~6 valent alcohol compound has a high boiling point, and is usually It is better from the viewpoint of pressure to raise the temperature and from the viewpoint of reducibility. By using polyol as a solvent, it is not necessary to additionally use a reducing agent.

Among the above-mentioned polyols, divalent alcohols are preferable from the viewpoint of not becoming high viscosity, and among them, ethylene glycol and propylene glycol are particularly preferable from the economic viewpoint.

Although the total usage amount of the above-mentioned polyol is not particularly limited, it is usually about 10,000 to 100,000 parts by mass, preferably 15,000 to 60,000 parts by mass relative to 100 parts by mass of the silver compound. When it is less than this, the reduction rate becomes slower, and if it is more, the productivity tends to deteriorate.

In addition, although the total usage amount of the solvent including or not including the polyol as a solvent is not particularly limited, it is usually about 10,000 to 100,000 parts by mass, preferably 15,000 to 60,000 parts by mass relative to 100 parts by mass of the silver compound.

When the total usage amount of the solvent is less than 10,000 parts by mass, the silver concentration in the reaction solution becomes too high, which may cause side reactions such as the formation of spherical powder, which may lower the yield of the thread. When the total amount of the solvent exceeds 100,000 parts by mass, the silver concentration in the reaction solution becomes too low, which lowers the reaction rate and reduces productivity.

In addition, although the heating temperature of the silver compound is not particularly limited, it is usually 60 to 300°C, preferably 100 to 200°C. In addition, the heating time is usually 0.1 to 48 hours, preferably 0.2 to 24 hours.

In addition, in order to remove the coating agent adsorbed on the surface, the silver nanowire produced by the above heating step is purified by telecentric separation, cross-flow filtration, etc., but the coating agent water used in this embodiment The solubility is higher than that of polyvinylpyrrolidone and can be removed by a simple washing step. Examples of solvents that can be used for cleaning include water, methanol, ethanol, isopropanol, N-propanol, N-butanol, isobutanol, sec-butanol, etc. Among these, methanol, ethanol, isopropanol It is preferable from the viewpoints of industrial ease of starting and ease of operation of solvent exchange in the subsequent step.

The silver nanowire obtained by the above manufacturing method has very few residues derived from the coating agent, and the resistance after coating of the prepared ink tends to decrease and at the same time, especially the dispersibility of the aqueous solvent becomes good.

In addition, the diameter of the obtained silver nanowire is about 20 to 250 nm, and the length is about 1 to 50 μm. In addition, the diameter and length of the silver nanowire can be measured according to the method described in the examples described later.

The ink of this embodiment contains the silver nanowire obtained by the above-mentioned manufacturing method. The content of silver nanowires in the ink is more preferable from the viewpoint of improving the conductivity of the pattern formed by the ink, but there is an upper limit from the viewpoint of suppressing optical characteristics or aggregation, 0.05 to 60 mass % Is better, and 0.1-30% by mass is even better. Especially when the transparent conductive film is used, the light transmittance is also considered, and 0.05 to 10% by mass is preferable, and 0.1 to 5% by mass is more preferable.

In addition, although 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 can be cited. Ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; alkylene glycol solvents such as ethylene glycol, diethylene glycol, propylene glycol and 1,3-propanediol; alkylene glycol Hydrocarbon solvents such as alkyl ethers, terpineol, toluene, hexane, etc. Alone 1 You can use 2 or more types together.

In addition, as a solvent added to the ink of the present embodiment, when water or a lower alcohol-based solvent is used from the viewpoint of the dispersibility of silver nanowires in the ink, it is more appropriate to add poly(N-vinylmethylamide) and poly( N-vinylacetamide) or poly(N-vinylacetamide), when using other organic solvents (more hydrophobic), it is more appropriate to add N-vinylpyrrolidone, poly-N-caprolactam, polyethylene Alcohol (N-methyl) acetamide, etc. Although the addition amount is not particularly limited, it is usually about 0.01 to 10 parts by mass, preferably 0.01 to 1 part by mass relative to 100 parts by mass of the silver nanowire. When the amount is too large, it is difficult to reduce the resistance, and when it is too small, the additive effect is not exhibited. These maintain the dispersibility of the silver nanowires in the ink and at the same time function as a 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.

In addition, the ink of the present embodiment can contain various additives other than the above (for example, surfactant, polymerizable compound, polymer, antioxidant, resist, viscosity adjuster, preservative) if necessary.

In addition, in particular, the substrate for printing the ink of this embodiment is not limited, and insulating materials such as resin, glass, ceramics, and paper, semiconductor materials, and conductors such as metals can be cited. Among these, examples of the resin substrate include polyethylene terephthalate substrate, triethylene cellulose substrate, polyethylene naphthalate substrate, polycarbonate substrate, and polyester substrate. , Acrylonitrile-butadiene-styrene substrate, polypropylene substrate, polystyrene substrate, polyamine Carbamate substrates, epoxy resin substrates, polyvinyl chloride-based substrates, polyamide-based substrates, etc.

[Examples]

Hereinafter, the present invention will be described in detail by exemplifying examples, but the present invention is not limited to these examples.

The analysis conditions of the examples are as follows.

<Molecular weight measurement>

The weight-average molecular weight Mw was measured by gel permeation chromatography (hereinafter abbreviated as GPC) and converted to the value of pullulan (standard sample). In addition, the measurement conditions of GPC are as follows.

Measuring device: HPLC made by Shodex

Eluent: distilled water

Detector: Shodex RI-201I

Pump: SHIMADZU LC-20AD

Column oven: SHODEX AO-30C

Resolution device: SHIMAZU SIC 480II Deta Station

Pump flow rate: 0.7mL/min

Column: Shodex GPC SB-806 HQ 2

Column temperature: 40℃

Sample concentration: 0.2% by mass

Injection volume: 200μL

<Observation of the shape of the silver nanowire>

The shape (length ‧ diameter) of the silver nanowires is the diameter of 100 nanowires observed using the ultra-high resolution energy field emission scanning electron microscope SU8020 (acceleration voltage 3~10kV) manufactured by Hitachi Global Advanced Technologies Co., Ltd.

<thermogravimetric analysis>

TG/DTA manufactured by NETZSCH was used for thermogravimetric analysis of the refined samples.

Synthesis Example 1 Synthesis of poly(N-vinylformamide)

After adding N-vinylformamide (Tokyo Chemical Industry Co., Ltd., 100g, 1.41mol) and 400g of pure water to completely dissolve in a 1L three-necked flask, replace the gas phase and liquid phase with nitrogen for 2 hours (gas phase system) Nitrogen circulation, liquid phase nitrogen bubbling). Only the nitrogen substitution in the liquid phase was stopped, and the temperature was raised to 60°C with the gas phase nitrogen flowing. After dissolving V-50 (made by Wako Pure Chemical Industries, Ltd., 0.9 g, 3.32 mmol) in 10 g of pure water as a polymerization initiator, it was added to the system using a syringe. After continuing the reaction at 60°C for 6 hours, add the reaction solution to the tray and place it in an oven. Slowly increase the temperature to 120°C under normal pressure while watching the drying condition without boiling. Finally, move to a vacuum oven to dry under reduced pressure for 24 hours. 77 g of poly(N-vinylformamide) was obtained as a white solid. According to the molecular weight measurement of GPC, Mw was 160,000.

Example 1 Manufacture of silver nanowire

20 g of propylene glycol and 0.68 g of poly(N-vinylformamide) (9.6 mmol) synthesized in Synthesis Example 1 were mixed into a reaction container for PPS-CTRL1 made by Tokyo Physical and Chemical Machinery Co., Ltd., at 60 Stir at ℃ for 1 hour to dissolve completely. 0.3 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 4 g of propylene glycol were mixed into a container bottle and stirred at room temperature to completely dissolve. After adding 0.738 g (26.6 μmol) of a 1% by mass propylene glycol solution of tetrabutylammonium chloride (manufactured by ACROS) to the reaction vessel, a dropping funnel was provided on the upper part of the reaction vessel and the silver nitrate solution prepared previously was charged. Nitrogen was circulated at a flow rate of 300 mL/min for 5 minutes from the manifold to replace the system with nitrogen. Stop the nitrogen in the manifold and set a thermometer to increase the internal temperature to 130°C. The contents of the dropping funnel were dropped at 130°C for 6 minutes, and the reaction was continued at 130°C for 1 hour. The reaction mixture was diluted 5 times with ethanol, and the silver nanowires were precipitated by using a centrifuge at a rotation speed of 6000 rpm for 5 minutes. After adding 50 g of ethanol, the operation was performed at 6000 rpm for 5 minutes, and the operation was repeated twice to wash the poly(N-vinylformamide) remaining in the system and the solvent. The shape of the line was measured using a field emission scanning electron microscope (FE-SEM) for the obtained line. Table 1 shows the shape of the silver nanowires obtained, and FIG. 1 shows the field emission scanning electron microscope (FE-SEM) image.

Example 2 Manufacture of silver nanowire

Instead of 0.68 g (9.6 mmol) of poly(N-vinylformamide) synthesized in Synthesis Example 1, poly(N-vinylacetamide) was used (hereinafter abbreviated as And PNVA (GPVA) GP191-405 (Mw: 130000, 0.817g, 9.6mmol), and the reaction time at 130°C was changed from 1 hour to 20 minutes except that silver nanoparticles were obtained under the same conditions as in Example 1. Line, determine the shape of the line. Table 1 shows the shape of the silver nanowires obtained, and FIG. 2 shows the field emission scanning electron microscope (FE-SEM) image.

Example 3

As the PNVA, except for GP 191-405 (Mw: 260000), silver nanowires were obtained under the same conditions as in Example 2 and the shape of the wires was measured. Table 1 shows the shape of the silver nanowires obtained, and FIG. 3 shows the field emission scanning electron microscope (FE-SEM) image.

Example 4

As the PNVA, except for GE 191-205 (Mw: 180000), silver nanowires were obtained under the same conditions as in Example 2 and the shape of the wires was measured. Table 1 shows the shape of the obtained silver nanowires, and FIG. 4 shows the field emission scanning electron microscope (FE-SEM) image.

Example 5

Instead of the 0.68 g (9.6 mmol) poly(N-vinylformamide) synthesized in Synthesis Example 1, a 9:1 copolymer of N-vinylacetamide and acrylonitrile (hereinafter abbreviated as NVA/AN, Except for Showa Denko Co., Ltd., Mw: 150000) except for 0.82 g (9.6 mmol), silver nanowires were obtained under the same conditions as in Example 1, and the shape of the wires was measured. Table 1 shows the obtained The shape of the silver nanowire is shown in Fig. 5 by a field emission scanning electron microscope (FE-SEM) image.

Example 6

Instead of the 0.68 g (9.6 mmol) poly(N-vinylformamide) synthesized in Synthesis Example 1, a 9:1 copolymer of N-vinylacetamide and methyl methacrylate (hereinafter abbreviated as NVA) is used /MMA, Showa Denko Corporation, Mw: 150000) Other than 0.82 g (9.6 mmol), silver nanowires were obtained under the same conditions as in Example 1, and the shape of the wires was measured. Table 1 shows the shape of the obtained silver nanowires, and FIG. 6 shows the field emission scanning electron microscope (FE-SEM) image.

Example 7

20g of propylene glycol and 0.54g (6.4mmol) of PNVA GP191-405 (Mw: 130000) were mixed into a reaction vessel for a personal organic synthesis device PPS-CTRL 1 made by Tokyo Physical and Chemical Machinery Co., Ltd., and stirred at 60°C for 1 hour to complete Dissolve. 0.075g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 1g of propylene glycol were mixed into a container bottle and stirred at room temperature to completely dissolve. After adding 0.738 g (26.6 μmol) of a 1% by mass propylene glycol solution of tetrabutylammonium chloride (manufactured by ACROS) to the reaction vessel, a dropping funnel was provided on the upper part of the reaction vessel and the silver nitrate solution prepared previously was charged. While the nitrogen was circulated from the branch tube at a flow rate of 300 mL/min to replace the system with nitrogen, the internal temperature was raised to 130°C. Spend 1 minute at an internal temperature of 130°C to drop the contents of the dropping funnel, and then hold at 130°C Continue the reaction for 1 hour. The reaction mixture was diluted 5 times with ethanol, and the silver nanowires were precipitated by using a centrifuge at a rotation speed of 6000 rpm for 5 minutes. After the addition of 50 g of ethanol, the operation was performed at 6000 rpm for 5 minutes, and the operation was repeated twice to wash the remaining PNVA and solvent in the system. The shape of the line was measured using a field emission scanning electron microscope (FE-SEM) for the obtained line. Table 1 shows the shape of the silver nanowires obtained, and FIG. 7 shows the field emission scanning electron microscope (FE-SEM) image.

Example 8

200g of propylene glycol and PNVA GP191-405 (Mw: 130000, 8.17g, 96mmol) were incorporated into a 1L four-necked flask (mechanical stirrer, dropping funnel, return tube, thermometer), and stirred at 60°C for 1 hour to completely dissolve. 3 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 40 g of propylene glycol were mixed into the flask and stirred at room temperature to completely dissolve. After a solution of 7.38 g (0.27 mmol) of 1% by mass propylene glycol in tetrabutylammonium chloride (manufactured by ACROS) was added to the flask, the silver nitrate solution prepared previously was put into a dropping funnel. Nitrogen was flowed from the top of the dropping funnel at 300 mL/min for 20 minutes to replace the system with nitrogen. The nitrogen in the manifold was stopped, and the temperature was raised until the internal temperature reached 130°C. The contents of the dropping funnel were dropped at an internal temperature of 130°C for 30 minutes, and the reaction was continued at 130°C for 60 minutes.

The reaction mixture was diluted to 4 times with methanol, and washed using a cross-flow filtration device (Sel Fit table tester manufactured by NGK Phil Technology Co., Ltd., pore size 2 μm). Table 2 shows the cleaning conditions and Analysis results due to TG/DTA.

Comparative example 1

Except that GE191-104 (Mw: 300,000) was used as the PNVA, the procedure for manufacturing the silver nanowire was carried out under the same conditions as in Example 2. Table 1 shows the shape of the product.

As shown in Table 1, the shape of the product of this comparative example is spherical, and silver nanowires cannot be produced. It can be thought that this is the reason why the weight average molecular weight Mw of PNVA is as high as 300,000.

Comparative example 2

The procedure for producing silver nanowires was carried out under the same conditions as in Example 2 except that GE191-405P (Mw: 80000) was used as PNVA. Table 1 shows the shape of the product.

As shown in Table 1, the shape of the product of this comparative example is particulate, and silver nanowires cannot be produced. I can think of this because the weight average molecular weight Mw of PNVA is as low as 80,000.

Comparative Example 3

Mix 200g of propylene glycol and 10.7g of polyvinylpyrrolidone K-90 (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter abbreviated as PVP K-90) (96mmol) into a 1L four-necked flask (mechanical stirrer, dropping funnel, return flow) Tube, thermometer), stirring at 60 ℃ for 1 hour to completely dissolve. Mix 3g of silver nitrate (made by Wako Pure Chemical Industries, Ltd.) and 80g of propylene glycol After entering the flask, stir at room temperature to completely dissolve. After a solution of 7.38 g (0.27 mmol) of 1% by mass propylene glycol in tetrabutylammonium chloride (manufactured by ACROS) was added to the flask, the silver nitrate solution prepared previously was put into a dropping funnel. Nitrogen was flowed from the top of the dropping funnel at 300 mL/min for 20 minutes to replace the system with nitrogen. The nitrogen in the manifold was stopped, and the internal temperature was raised to 160°C. The contents of the dropping funnel were dropped at an internal temperature of 160°C for 30 minutes, and the reaction was continued at 160°C for 60 minutes.

The reaction mixture was diluted to 4 times with methanol, and washed using a cross-flow filtration device (Sel Fit table tester manufactured by NGK Phil Technology Co., Ltd., pore size 2 μm). Table 2 shows the analysis results by cleaning conditions and TG/DTA.

It was found that after repeating the filtration and washing step by lateral flow filtration 6 times, the residual amount of the resin in Example 8 using PNVA was 0.05% by mass, and a large amount of 0.29% by mass in Comparative Example 3 using PVP The resin cannot be washed and remains.

Claims (9)

A method for manufacturing silver nanowires, which includes R-CONHR' (R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms) contained in a monomer unit, and R'is a carbon number having a carbon-carbon double bond The step of heating the silver compound in the presence of a polymer having a weight average molecular weight of 100,000 to 280,000 and a reducing agent in the second-stage amide compound represented by 2 or 3). For example, the method for manufacturing silver nanowires according to item 1 of the patent application, wherein the aforementioned polymer is selected from poly(N-vinylformamide), poly(N-vinylacetamide) or poly(N-ethylene More than one type of polymer). For example, the method of manufacturing silver nanowires according to item 1 or 2 of the patent application, wherein the aforementioned silver compound is silver nitrate, silver hexafluorophosphate, silver fluoride borate, silver perchlorate, silver chlorate, silver chloride, bromide Any one of silver, silver fluoride, silver carbonate, silver sulfate, silver acetate, and silver trifluoroacetate. A method for manufacturing silver nanowires according to item 1 or 2 of the patent application scope, wherein a polyhydric alcohol is contained as the aforementioned reducing agent and/or solvent. For example, in the method of manufacturing a silver nanowire according to item 4 of the patent application, the aforementioned polyol is an alcohol compound having 2 to 6 carbon atoms and 2 to 6 valences. For example, in the method for manufacturing silver nanowires according to item 4 of the patent application range, 10,000 to 100,000 parts by mass of the aforementioned polyol is used with respect to 100 parts by mass of the aforementioned silver compound. For example, the manufacturing method of silver nanowires according to item 1 or 2 of the patent application scope, in which a fourth-grade ammonia salt is further added. For example, the manufacturing method of the silver nanowire in the fourth item of the patent scope, Furthermore, a fourth-grade ammonia salt is added. A method of manufacturing silver nanowires, which further includes removing the aforementioned polymerization of adsorbing on the surface of the silver nanowires obtained by the method of manufacturing silver nanowires according to any one of claims 1 to 8 Steps.

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