KR102147466B1 - Conductive Ink and the Fabrication Method of Conductive Film using Thereof - Google Patents

Abstract

The conductive ink according to the present invention comprises a metal nanostructure; Water-soluble polymer; And metal halides; And a polar solvent.

Description

Conductive Ink and the Fabrication Method of Conductive Film using Thereof}

The present invention relates to a conductive nanostructure-based conductive ink and a method of manufacturing a conductive film using the same.

Transparent conductive films are transparent in fields that require both transparency and conductivity, such as flat liquid crystal displays, touch panels, electroluminescent devices, and photovoltaic cells. It is widely used as an electrode, and a conductive film is also widely used as an optical film such as anti-reflection or luminance improvement, anti-static layers or electromagnetic wave shielding layers.

Metal oxides such as indium tin oxide (ITO) have excellent optical transparency and electrical conductivity, but are easily damaged by physical impact and are not physically deformable, and high cost is consumed during manufacturing. However, there is a limit to requiring a high-temperature process.

In the case of a conductive polymer, there is a problem in that the electrical and optical properties are deteriorated, as well as chemical and long-term stability.

Accordingly, the demand for a transparent conductive film that has excellent electrical and optical properties, can stably maintain its physical properties for a long period of time, and can physically deform is continuously increasing.

In accordance with this demand, a conductive film having a structure in which a network of metal nanowires such as silver nanowires is embedded in an organic matrix, as in Korean Patent Application Publication No. 2013-0135186, has been developed.

In the case of such a metal nanowire-based conductive film, binding between metal nanowires is required to obtain lower electrical resistance and excellent mechanical properties. For binding between metal nanowires, processes such as melting and bonding the contacts between nanowires by heating the nanowires applied to the substrate or photo-sintering by irradiating strong pulsed white light are performed.However, in the case of heating, the process is performed at a relatively high temperature. Due to the complexity of the process, such as light irradiation such as white light, photo sintering is suppressed by an organic binder, and light for sintering must be irradiated after removing the binder, the process is complex and mass production based on a continuous process In case the binder is not removed beforehand, high optical energy is required to decompose the binder, and thus there is a problem in that the substrate is damaged like heating.

Republic of Korea Patent Publication No. 2013-0135186

The present invention enables the formation of a network of uniformly dispersed metal nanostructures even when applied to a large area, is substantially free from thermal damage, and is capable of producing a conductive film having excellent electrical and optical properties, and conductive ink using the same. It is to provide a method of manufacturing a film.

The conductive ink according to the present invention comprises a metal nanostructure; Water-soluble polymer; And metal halides; And a polar solvent.

In the conductive ink according to an embodiment of the present invention, the water-soluble polymer may include cellulose ether.

In the conductive ink according to an embodiment of the present invention, the weight ratio of the metal halide: cellulose ether may be 1:2 or more.

In the conductive ink according to an embodiment of the present invention, the weight ratio of the metal nanostructure: the metal halide may be 1:0.2 to 0.4.

In the conductive ink according to an embodiment of the present invention, the conductive composition may contain 0.01 to 5% by weight of metal nanostructures.

In the conductive ink according to an embodiment of the present invention, the weight ratio of the metal nanostructure: the water-soluble polymer may be 1: 0.5 to 1.5.

In the conductive ink according to an embodiment of the present invention, the metal nanostructure is at least one selected from gold, silver, platinum, palladium, copper, nickel, or nanowires of an alloy thereof, nanotubes, nanorods, and metal nanobelts. I can.

In the conductive ink according to an embodiment of the present invention, the metal nanostructure may include metal nanowires having an aspect ratio of 5 to 50 nm and an aspect ratio of 100 to 10000.

The conductive ink according to an embodiment of the present invention may further include a second water-soluble polymer that is a polyoxyalkylene polymer, a polyacrylic polymer, a polyvinyl polymer, a polysaccharide, or a mixture thereof.

The present invention includes a method of manufacturing a conductive film using the conductive ink described above.

The method of manufacturing a conductive film according to the present invention includes a) forming a network of metal nanostructures by applying the aforementioned conductive ink to a substrate.

The method of manufacturing a conductive film according to an embodiment of the present invention may further include a washing step after step a).

As the conductive ink according to the present invention is a water-based ink, it is eco-friendly, has excellent work safety and commercial properties, and can produce a conductive film having uniform and excellent electrical and optical properties through an extremely simple process of simply applying and drying the ink on a substrate. There is an advantage to be able to.

1 is a view showing the ratio of the sheet resistance (Ω / sq.) of the conductive film prepared in Preparation Examples 1 to 9 divided by the sheet resistance of the conductive film prepared in Preparation Example 8,
2 is a view showing the ratio of the sheet resistance (Ω / sq.) of the conductive film prepared in Preparation Examples 11 to 15 divided by the sheet resistance of the conductive film prepared in Preparation Example 8,
3 is a diagram showing a ratio of the sheet resistance (Ω/sq.) of the conductive films prepared in Preparation Examples 16 to 23 divided by the sheet resistance of the conductive film prepared in Preparation Example 8. FIG.

Hereinafter, the conductive ink of the present invention and a method of manufacturing the same will be described in detail. At this time, unless there are other definitions in the technical and scientific terms used, they have the meanings commonly understood by those of ordinary skill in the technical field to which this invention belongs, and unnecessarily obscure the subject matter of the present invention in the following description. Description of possible known functions and configurations will be omitted.

In order to manufacture a nanostructure-based conductive film having uniform physical properties in a large area essential for commercialization, the applicant of the present invention first requires uniform coating of nanostructures with the aid of a polymer that can play the role of a binder and dispersant. I realized it should be. However, the polymer contained together with the nanostructures in the ink causes incomplete binding between the nanostructures or requires high energy to limit the usable substrate, and requires a prior process for removing the polymer. Settlement) is adversely affected.

As a result of conducting research on a nanostructure-based conductive ink composition using various materials for a long period of time to solve the adverse effects of such polymers, the Applicant has excellent commerciality and eco-friendly water-based ink, ensuring uniform physical properties over a large area. Development of a nanostructure-based aqueous ink that contains a polymer that can be used and produces a conductive film that enables stable electrical bonding between nanostructures without applying additional energy, even though it is difficult to handle such as acids and does not use substances harmful to the human body. Thus, the present invention was filed.

The conductive ink according to the present invention comprises a metal nanostructure; Water-soluble polymer; And metal halides; And a polar solvent.

The metal of the metal nanostructure is not particularly limited, but may include gold, silver, platinum, palladium, copper, nickel, or an alloy thereof.

The metal nanostructure may be at least one selected from metal nanowires, metal nanotubes, metal nanorods and metal nanobelts, and includes metal nanowires capable of forming a stable current transfer path in a relatively small amount by a high aspect ratio. It is advantageous. According to an advantageous example, the metal nanostructure may include a nanowire of gold, silver, platinum, palladium, copper, nickel, or an alloy thereof, and according to a more specific and advantageous example, the metal nanostructure may include a silver nanowire. When the metal nanostructure includes a metal nanowire, the average short axis diameter of the metal nanowire may be 5 to 50 nm, the aspect ratio may be 100 to 10000, and more specifically, the average short axis diameter may be 10 to 45 nm, and the aspect ratio May be 100 to 5000, and more specifically, the uniaxial average diameter may be 15 to 30 nm, and the aspect ratio may be 500 to 3000.

The content of the metal nanostructures in the conductive ink can be appropriately adjusted in consideration of the specific use of the conductive film to be manufactured using the conductive ink. As an example, the use of the transparent electrode is a conductive ink containing 0.01 to 5% by weight of metal nanostructures, more specifically 0.05 to 1% by weight of metal nanostructures, and more specifically 0.05 to 0.5% by weight of metal nanostructures. It may contain. The content of such a trace amount of metal nanostructures is advantageous in terms of high transmittance. However, in the case of containing a very small amount of metal nanostructures ranging from 0.05 to 1% by weight, it is more preferable that the metal nanostructures contain metal nanowires so that a large amount of contact points between the metal nanostructures can be formed to form a stable current movement path. good.

The polar solvent contained in the conductive ink preferably contains water. Water can dissolve water-soluble polymers and metal halides, can act as a dispersion medium for metal nanostructures, does not chemically react with substrates, has excellent commerciality and process safety, and has a high dissolved oxygen saturation concentration, which is an effective reaction field ( reaction field) can be provided.

As described above, it is preferable that the polar solvent contains water, but the present invention should not be interpreted as excluding polar solvents other than water, and when necessary in consideration of the specific application method, water and other polar solvents are mixed. It goes without saying that a mixed solvent may be used. Specific examples of polar solvents used as mixed solvents include 2-butoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene glycol butyl ether, 2-ethoxyethyl acetate, ethylene glycol diacetate , Terpineol (terpineol), isobutyl alcohol, or a mixture thereof, etc., but the present invention cannot be limited by the type of polar solvent (polar solvent other than water) mixed with water.

The water-soluble polymer may be a cellulose ether (cellulose ether type), and advantageously, C1-C3 alkyl hydroxy C1-C3 alkyl cellulose, more advantageously, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, ethyl hydroxyethyl cellulose Or a mixture thereof. Water-soluble when the water-soluble polymer comprises a cellulose ether, in particular a C1-C3 alkyl hydroxy C1-C3 alkyl cellulose, more specifically, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, ethyl hydroxyethyl cellulose or mixtures thereof Even in the presence of a polymer, a stronger and more stable binding (fusion) between metal nanostructures can be made with the help of a halogen derived from a simple metal halide rather than an acid, making it possible to manufacture a conductive film having a remarkably low surface resistance. When the conductive ink is simply applied, binding between metal nanostructures can be made very uniformly even on a large area. As described above, the water-soluble polymer is a cellulose ether, in particular, a C1-C3 alkyl hydroxy C1-C3 alkyl cellulose, more specifically, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, ethyl hydroxyethyl cellulose or mixtures thereof. In the case of containing, while the conductive ink maintains the same state as the metal halide-free ink, metal nanoparticles are produced by a halogen ion-derived reaction in the process of coating and drying (coating and drying the conductive ink) in which the water-soluble polymer is present and maintained. The contacts between the structures can be bonded at room temperature.

The content of the cellulose ether in the conductive ink may be adjusted according to the content of the metal halide that generates halogen ions. Specifically, the weight ratio of the metal halide: cellulose ether contained in the conductive ink may be 1: 2 or more, and in this case, the contact between the nanostructures is stably bonded to produce a conductive film having a constant and low surface resistance. That is, a cellulose ether, in particular, a C1-C3 alkyl hydroxy C1-C3 alkyl cellulose, more specifically, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, ethyl hydroxyethyl cellulose or a mixture thereof in a weight ratio of metal halide If the contrast is less than 2, there is a risk of incomplete binding between nanostructures due to a reaction derived from a metal halide.

When the weight ratio of the cellulose ether to the weight of the metal halide is 2 or more, a conductive film having excellent electrical conductivity can be produced by a simple process of applying and drying ink even in the presence of a water-soluble binder, and the drying speed of the applied ink and substantially Regardless, a conductive film having a stably low surface resistance can be produced. 2 or more cellulose ethers, in particular, C1-C3 alkyl hydroxy C1-C3 alkyl cellulose, more specifically, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, ethyl hydroxyethyl cellulose, or mixtures thereof based on the weight of the metal halide. When contained, the maximum content of cellulose ether may be appropriately adjusted as necessary, as it is possible to reproducibly prepare a conductive film having a low surface resistance. In one embodiment, a metal halide: a cellulose ether, in particular, a C1-C3 alkyl hydroxy C1-C3 alkyl cellulose, more specifically, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, ethyl hydroxyethyl cellulose, or their The weight ratio of the mixture may be 1: 2 to 10. However, if the content of the water-soluble polymer in the conductive ink is excessively high, there is a risk that the electrical properties of the produced conductive film will be reduced. If the content of the water-soluble polymer is too small, it is difficult to uniformly apply the metal nanostructures, so the conductive film has homogeneous electrical properties As it becomes difficult to manufacture, it is preferable that the content of the water-soluble polymer in the conductive ink has an appropriately controlled value.

Specifically, in terms of manufacturing a conductive film having uniform and excellent electrical properties, it is advantageous that the weight ratio of the metal nanostructure in the conductive ink: the water-soluble polymer satisfies 1: 0.5 to 1.5, specifically 1: 0.8 to 1.2. The polymer has a weight ratio of the water-soluble polymer to the weight of the metal nanostructure in a range that satisfies the weight ratio of 1: 0.5 to 1.5, specifically 1: 0.8 to 1.2, and the weight of the metal halide to the weight of the cellulose ether, in particular, C1-C3 alkyl hydroxy C1-C3 Alkyl cellulose, more specifically, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, ethyl hydroxyethyl cellulose, or a mixture thereof preferably satisfies the condition that the weight ratio is 2 or more.

As described above, the conductive ink is a water-soluble polymer with a cellulose ether, in particular, a C1-C3 alkyl hydroxy C1-C3 alkyl cellulose, more specifically, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, ethyl hydroxyethyl cellulose or It is advantageous to contain mixtures of these, more advantageously cellulose ethers, in particular C1-C3 alkyl hydroxy C1-C3 alkyl cellulose, more particularly, hydroxyethyl methylcellulose, hydroxypropyl methyl relative to the weight of the metal halide. It is preferable that the weight ratio of cellulose, ethyl hydroxyethyl cellulose or a mixture thereof is 2 or more. However, the present invention is a water-soluble polymer as a cellulose ether, in particular, a C1-C3 alkyl hydroxy C1-C3 alkyl cellulose, more specifically, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, ethyl hydroxyethyl cellulose or a mixture thereof It should not be construed as excluding other water-soluble polymers, and it goes without saying that it may further include other types of water-soluble polymers capable of improving binding strength and serving as a dispersant or a binder together with an advantageous amount of cellulose ether.

Cellulose ethers, in particular, C1-C3 alkyl hydroxy C1-C3 alkyl cellulose, more specifically, when hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, ethyl hydroxyethyl cellulose or mixtures thereof are referred to as the first water-soluble polymer , If necessary, the water-soluble polymer may further include a second water-soluble polymer different from the first water-soluble polymer together with the first water-soluble polymer.

The second water-soluble polymer, so that the second water-soluble polymer can be used as a viscosity modifier to adjust to have a viscosity suitable for a specific application method, a binder for binding metal nanostructures to an ink application object, and/or a dispersant for metal nanostructures. Oxyalkylene-based polymers, polyacrylic polymers, polyvinyl-based polymers, polysaccharides, or mixtures thereof may be included. Specifically, the second water-soluble polymer includes polyoxyalkylene polymers such as polyethylene glycol, polypropylene glycol, and polyethylene glycol-propylene glycol copolymer; Polyacrylic polymers such as sodium polyacrylate, polyethylacrylate, and polyacrylamide; Polyvinyl polymers such as polyvinyl alcohol, polyvinyl acetate, and polyvinylpyridone; Glycogen, amylose, amylopectin, calose, agar, algin, alginate, pectin, carrageenan, cellulose, chitin, chitosan, curdran, dextran, fructan, collagen, gellan gum, gum arabic, Starch, xanthan, gum tragacanth (gum tragacanth), carayan (carayan), carabean (carabean), polysaccharides such as glucomannan; one or more may be selected from the group consisting of. At this time, the molecular weight (number average molecular weight, Mn) of the water-soluble polymer (the first water-soluble polymer or the second water-soluble polymer) may be 5x10 ⁵ or less, specifically 3,000 to 2x10 ⁵ , but the present invention is not limited thereto. In addition, the content of the second water-soluble polymer is not particularly limited, as long as the first water-soluble polymer satisfies the condition of 2 parts by weight or more based on the weight of the metal halide, but the total water-soluble polymer (the first water-soluble polymer and the It goes without saying that the content of the second water-soluble polymer can be appropriately adjusted within a range in which the weight ratio of the 2 water-soluble polymer) satisfies 1: 0.5 to 1.5, specifically 1: 0.8 to 1.2.

Can be a halogen source capable of providing a halogen anion selected from one or more of ^- a metal halide is a dispersion medium and dissolved in a solvent, a polar solvent of a water-soluble polymer F of the metal nanostructure ^-, Cl ^-, I ^- and Br. As a halogen source, not only a halogen salt, which is a metal halide, but also a halogen acid such as HCl, etc. can be exemplified, but in the case of an acid that can also play a role of removing water-soluble polymers, process construction and maintenance are required due to toxicity. It is difficult and the waste liquid generated when washing the conductive film must be separately managed and treated, and it is harmful to the human body, so there is a limit to commercial use. Accordingly, the conductive ink according to an embodiment of the present invention is a water-soluble polymer with a cellulose ether, in particular, a C1-C3 alkyl hydroxy C1-C3 alkyl cellulose, more specifically, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, ethyl By containing hydroxyethyl cellulose or a mixture thereof, as well as metal halides as a source of halogen, process safety is excellent, environmentally friendly, and is easily cleaned and removed using polar solvents including water, and advanced waste management is not required. It has the advantage of being able to manufacture a conductive film having excellent electrical properties by being bonded at room temperature by simple application and drying. The metal halide is preferably an alkali metal halide in consideration of ease of supply and demand, cost reduction, and eco-friendly characteristics. The alkali metal halide may be NaCl, NaBr, NaI, NaF, KCl, KBr, KI, KF, LiCl, LiBr, LiI, LiF, or a mixture thereof. When the metal halide is an alkali metal halide, NaF, NaCl, KCl, or a mixture thereof may be included so that stable binding can be achieved at the contact points between metal nanostructures by simple application. The weight ratio of the metal nanostructure: metal halide contained in the conductive ink may be 1: 0.2 to 0.4, more preferably 1: 0.2 to 0.35. When the content of metal halide is as low as 0.2, the binding effect between metal nanostructures is insignificant, so it may be difficult to form an integrally bonded metal nanostructure network.If the conductive ink contains an excessive amount of metal halide, There is a risk that the haze property of the conductive film is deteriorated.

The present invention includes a method of manufacturing the conductive ink described above.

In detail, the method for preparing a conductive ink according to the present invention includes a mixing step of injecting and mixing a metal halide in a first solution containing a water-soluble polymer, a metal nanostructure, and a polar solvent.

The specific material and content of the water-soluble polymer, the metal nanostructure, the polar solvent, and the metal halide are similar to or the same as the specific material and the content of the water-soluble polymer, the metal nanostructure, the polar solvent, and the metal halide of the conductive ink. The method of manufacturing the conductive ink includes all the contents of the conductive ink described above.

The present invention includes a method of manufacturing a conductive film using the conductive ink described above.

The method of manufacturing a conductive film according to the present invention includes a) applying the above-described conductive ink to a substrate to form a network of metal nanostructures, and may further include a washing step after step a).

The substrate to which the conductive ink is applied may be appropriately selected according to the use of the conductive film. Specifically, the substrate to which the conductive ink is applied is an insulating substrate, and may be a transparent or opaque substrate, and may be a physically rigid substrate or a flexible substrate. Examples of the hard transparent insulating substrate include glass, polycarbonate, acrylic polyethylene terephthalate, and the like, and examples of the flexible transparent insulating substrate include polyester-based such as polyester naphthalate and polycarbonate; Polyolefin-based such as linear, branched, and cyclic polyolefins; Polyvinyl systems such as polyvinyl chloride, polyvinylidene chloride, polyvinyl acetal, polystyrene and polyacrylic; Cellulose ester bases such as cellulose triacetate or cellulose acetate; Polysulfones such as polyethersulfone; Polyimide-based or silicone-based, but are not limited thereto.

Application of the conductive ink may include printing, specifically inkjet printing, fine contact printing, imprinting, gravure printing, gravure-offset printing, flexographic printing, offset/reverse offset printing, slot die coating, bar coating, Any method known to be used for application of dispersions containing one-dimensional nanostructures such as carbon nanotubes or nanowires, such as blade coating, spray coating, dip coating, and roll coating, may be used.

After application of the conductive ink, a drying step for volatilizing and removing the solvent in the coating film may be further performed, and room temperature drying, hot air drying, cold air drying, heat drying, or a combination thereof may be used depending on the process design. Heat drying does not adversely affect the substrate, and drying may be performed at a temperature (for example, 40 to 80°C) at which the solvent can be volatilized and removed, as well as hot air drying may be performed at a temperature of 80 to 130°C. Of course. Specifically, the method of manufacturing a conductive film includes preparing a conductive film including a network of metal nanostructures in which contacts between metal nanostructures are bonded by applying conductive ink to an insulating substrate and drying the coating film at room temperature or hot air. I can. As described above, after preparing the conductive film by drying the coating film, the step of washing the obtained conductive film may be further performed, and metal halide remaining in the conductive film may be removed by such washing. Washing may be performed using a conventional washing method such as spraying a polar solvent containing water or dipping in a polar solvent containing water.

After washing is performed, if necessary, a step of forming an insulating transparent coating layer on the network of the metal nanostructure may be further performed, and the insulating transparent coating layer may be performed by applying and drying a solution in which the insulating transparent resin is dissolved. Specific examples of the insulating transparent resin include polyesters such as polyester naphthalate and polycarbonate; Polyolefin-based such as linear, branched, and cyclic polyolefins; Polyvinyl systems such as polyvinyl chloride, polyvinylidene chloride, polyvinyl acetal, polystyrene and polyacrylic; Cellulose ester bases such as cellulose triacetate or cellulose acetate; Polysulfones such as polyethersulfone; Polyimide-based or silicone-based, but are not limited thereto.

(Production Example 1)

Ag nanowires (average short axis diameter 35 nm, average length 25 μm) and hydroxypropyl methylcellulose (HPMC, Mn=86,000, METHOCEL) were added to deionized water and mixed to prepare a nanowire dispersion, and NaCl was added to the nanowire dispersion. It was added and mixed to prepare a water-based conductive ink containing 0.134% by weight Ag nanowire, 0.136% by weight HPMC, 0.036% by weight NaF and the remaining amount of water.

A water-based conductive ink was applied to a polyethylene terephthalate (PET, refractive index 1.55) film (20cmx1m) using a slot die, the coating film was dried at room temperature, and washed with water to prepare a conductive film. At the time of slot die coating, the slot die coating thickness was 50 μm, the discharge amount was 0.25 ml/s, the die gap was 80 μm, and the die shim was 100 μm.

(Production Examples 2 to 9)

In Preparation Example 1, according to Table 1 instead of HPMC, polyvinyl alcohol (PVA, Mn=22,000), polyvinylpyrrolidone (PVP, Mn=10,000), polyethylene glycol (PEG, Mn=20,000), hydro Conductive ink and conductivity in the same manner as in Preparation Example 1, except that oxyethylmethylcellulose (HEMC, Mn=41,000), ethylhydroxyethylcellulose (EHEC, Mn=63,000) was used, and NaF or NaCl was used as a metal halide. The film was prepared.

(Table 1)

(Production Example 10)

In Preparation Example 1, a conductive film was prepared in the same manner as in Preparation Example 1 by using the nanowire dispersion as a conductive ink without adding NaF, which is a metal halide, to the nanowire dispersion.

(Production Examples 11-15)

1.34 g of Ag nanowire (average short axis diameter 35 nm, average length 25 μm), 0.28 g NaCl and 0.30 g (Production Example 11), 0.50 g (Production Example 12), 0.70 g (Preparation Example 13) based on solid content per 1 kg of aqueous conductive ink ), 0.90 g (Preparation Example 14) or 1.10 g (Preparation Example 15) of a water-based conductive ink was prepared similarly to Preparation Example 1 to contain hydroxypropyl methylcellulose, and a conductive film was prepared in the same manner as Preparation Example 1. .

(Production Examples 16 to 21)

1.34 g of Ag nanowire (average short axis diameter 35 nm, average length 25 μm), 0.40 g NaF and 0.50 g (Production Example 16), 0.60 g (Production Example 17), 0.70 g (Production Example 18) based on solid content per 1 kg of aqueous conductive ink ), 0.80 g (Preparation Example 19), 0.90 g (Preparation Example 20) or 1.00 g (Preparation Example 21) of hydroxypropyl methylcellulose to prepare a water-based conductive ink similarly to Preparation Example 1, and Preparation Example 1 A conductive film was prepared in the same manner as.

(Production Examples 22-23)

1.34 g of Ag nanowire (average short axis diameter 35 nm, average length 25 μm), 0.10 g (Preparation Example 22) or 0.65 g (Preparation Example 23) NaCl and 1.36 g hydroxypropyl methylcellulose, based on solid content per 1 kg of aqueous conductive ink Thus, a water-based conductive ink was prepared in the same manner as in Preparation Example 1, and a conductive film was prepared in the same manner as in Preparation Example 1.

(Production Example 24)

A conductive ink was prepared in the same manner as in Preparation Example 1, and a conductive film was prepared in the same manner as in Preparation Example 1 except for drying with hot air at 110° C. instead of drying at room temperature.

1 is a view showing the ratio of the sheet resistance (Ω / sq.) of the conductive film prepared in Preparation Examples 1 to 9 divided by the sheet resistance of the conductive film prepared in Preparation Example 10. The sheet resistance of the conductive film of Preparation Example 10, which is a reference in FIG. 1, is the sheet resistance of the conductive film subjected to washing for the same comparison with other Preparation Examples containing NaCl. The sheet resistance of the conductive film prepared in Preparation Example 10 was 35.7Ω/sq. At this time, the sheet resistance of the prepared conductive film was measured 20 times at a random position and an average value was used.

As can be seen from FIG. 1, it can be seen that the sheet resistance of the prepared conductive film varies greatly depending on the type of water-soluble polymer contained in the conductive ink. As in Preparation Examples 1 and 5 to 9, the conductive ink is hydroxyethyl When containing C1-C3 alkyl hydroxy C1-C3 alkyl cellulose such as methylcellulose, hydroxypropyl methylcellulose, and ethyl hydroxyethyl cellulose, the sheet resistance is significantly reduced. Through this, it can be seen that it is advantageous for the conductive ink to contain C1-C3 alkyl hydroxy C1-C3 alkyl cellulose in order to exhibit the binding effect between Ag nanowires by halogen ions. In the case of other water-soluble polymers, the effect of halogen ions is It can be seen that it does not appear substantially. Furthermore, in the case of Preparation Examples 2 to 4, it can be seen that it is advantageous to contain hydroxypropyl methylcellulose in terms of uniform distribution and stable binding of nanowires, since the variation in sheet resistance by position of the film is very large.

Figure 2 is a view showing the ratio of the sheet resistance (Ω / sq.) of the conductive film prepared in Preparation Examples 11 to 15 divided by the sheet resistance of the conductive film prepared in Preparation Example 10, Figure 3 is in Preparation Examples 16 to 23 It is a diagram showing the ratio of the sheet resistance (Ω/sq.) of the prepared conductive film divided by the sheet resistance of the conductive film prepared in Preparation Example 10.

In the case of the conductive films prepared in Preparation Example 11, Preparation Example 12, Preparation Example 16, and Preparation Example 17, it was confirmed that not only the effect of reducing the sheet resistance was insignificant, but also the sheet resistance was greatly varied for each film position to be measured.

In addition, as a result of measuring the sheet resistance of the conductive film according to the relative content of C1-C3 alkyl hydroxy C1-C3 alkyl cellulose compared to the metal halide content through Preparation Examples 11 to 21, the conductive ink was at least twice as high as C1-C3 based on metal halide. It can be seen that the sheet resistance of the conductive film is stabilized at a level of 22 to 24 (Ω/sq.) when the alkyl hydroxy C1-C3 alkyl cellulose is contained. That is, in order to stably exhibit the binding effect between Ag nanowires by halogen ions, it can be seen that it is advantageous for the conductive ink to contain at least twice the C1-C3 alkyl hydroxy C1-C3 alkyl cellulose based on the metal halide.

In addition, as can be seen in Preparation Examples 1, 13 to 15, Preparation Examples 19 to 21, Preparation 22 and Preparation 23, in order to stably exhibit the effect of improving the conductivity at the silver nanowire contact point by halogen ions, the ink It can be seen that it is advantageous to contain a metal halide of 20% or more of the contained silver nanowire mass.

The light transmittance of the conductive films prepared in Preparation Example 1, Preparation Examples 5 to 9, Preparation Examples 13 to 15, Preparation Examples 19 to 21, and Preparation Example 23 was 90.2 to 90.8% based on 550 nm, and the haze was 1.23 to 1.28%. In the case of Preparation Example 23 containing a large amount of metal halide, although a conductive film having excellent electrical properties was produced, the haze was 1.40%, and when an excessive amount of metal halide was contained, the haze property of the film was deteriorated.

In addition, as in Preparation Example 24, as a result of drying by blowing hot air at 110° C., the average sheet resistance of the prepared conductive film was 22.3 (Ω/sq.), and the conductive film prepared by room temperature drying of Preparation Example 1 and electrical and It was confirmed that a conductive film having substantially similar optical properties was produced, and it was confirmed that the quality of the produced conductive film did not change sensitively to process conditions.

As described above, in the present invention, specific matters and limited embodiments and drawings have been described, but this is provided only to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention is Those of ordinary skill in the relevant field can make various modifications and variations from this description.

Therefore, the spirit of the present invention is limited to the described embodiments and should not be defined, and all things that are equivalent or equivalent to the claims as well as the claims to be described later fall within the scope of the spirit of the present invention. .

Claims (11)

Silver nanostructures; Water-soluble polymers including C1-C3 alkyl hydroxy C1-C3 alkyl cellulose; Sodium halide; And a polar solvent.
delete The method of claim 1,
The sodium halide: C1-C3 alkyl hydroxy C1-C3 alkyl cellulose weight ratio of 1: 2 or more conductive ink. The method of claim 1,
The silver nanostructure: the weight ratio of sodium halide 1: 0.2 to 0.4 conductive ink. The method of claim 1,
The conductive ink is a conductive ink containing 0.01 to 5% by weight of silver nanostructures. The method of claim 1,
The silver nanostructure: the weight ratio of C1-C3 alkyl hydroxy C1-C3 alkyl cellulose is 1: 0.5 to 1.5 conductive ink.
delete The method of claim 1,
The silver nanostructure is a conductive ink containing silver nanowires having a minor axis diameter of 5 to 50 nm and an aspect ratio of 100 to 10000. The method of claim 1,
The conductive ink is a conductive ink further comprising a second water-soluble polymer that is a polyoxyalkylene polymer, a polyacrylic polymer, a polyvinyl polymer, a polysaccharide, or a mixture thereof. a) forming a network of metal nanostructures by applying the conductive ink according to any one of claims 1, 3 to 6, and 8 to 9 to a substrate; of a conductive film comprising: Manufacturing method. The method of claim 10,
After the step a), the method of manufacturing a conductive film further comprising a washing step.

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