KR20180071808A - Composition for forming conductive layer and conductive layer manufactured using the same - Google Patents

Abstract

The present invention relates to a composition for forming a conductive film used as a transparent electrode included in a large-area display. The present invention provides the composition for forming the conductive film, which has high stability against ultraviolet rays to have low surface resistance and can form a conductive film exhibiting high transmittance.

Description

TECHNICAL FIELD [0001] The present invention relates to a composition for forming a conductive film and a conductive film using the same. BACKGROUND ART [0002]

The present invention relates to a composition for forming a conductive film used for forming a transparent conductive film in a large-area display manufacturing process.

In a large-area display, a transparent conductive film (that is, a transparent electrode) that transmits light to transmit an image and generates an electric current is one of the key components. The transparent conductive film must be chemically stable, excellent in smoothness, . As materials of the transparent conductive film, oxides such as indium tin oxide (ITO), fluorine doped tin oxide, conductive polymers, and metal nanowires are used.

Indium tin oxide (ITO) has a high transmittance and is excellent in conductivity and is widely used in the production of a transparent conductive film. However, the indium tin oxide has a problem in that the manufacturing cost of the transparent conductive film is increased due to the limited amount of the storage.

The conductive polymer is a material that can replace indium tin oxide. However, since the solubility of the conductive polymer is low, a transparent conductive film using the conductive polymer is difficult to manufacture and the energy band gap is 3 eV or less.

The transparent conductive film prepared using the metal nanowire may exhibit a surface resistance similar to that of the transparent conductive film made of indium tin oxide, but is very vulnerable to ultraviolet rays, resulting in a problem that the surface resistance is rapidly increased during use. That is, a polymer compound is used as a binder material when forming a transparent conductive film with a metal nanowire. As the polymer compound is optically dissociated by ultraviolet rays, oxygen is generated, and the metal nanowires are oxidized by the generated oxygen, The surface resistance of the film is drastically increased.

Accordingly, an ultraviolet stabilizer is used to protect the transparent conductive film from ultraviolet rays, but a satisfactory level of effect is not obtained.

Korean Patent Publication No. 2007-0096941

The present invention provides a composition for forming a conductive film which is high in stability against ultraviolet rays and low in surface resistance and capable of forming a conductive film exhibiting high transmittance.

The present invention also provides a conductive film produced using the composition for forming a conductive film.

In order to solve the above problems, the present invention provides a metal nanowire; bookbinder; Ultraviolet stabilizer; And an inorganic oxide, wherein the inorganic oxide has an average particle size (D ₅₀ ) of 20 nm or less.

The present invention also provides a conductive film produced using the composition for forming a conductive film.

Since the composition for forming a conductive film of the present invention contains an inorganic oxide having a specific particle size, when a conductive film is formed using the composition, the stability against ultraviolet rays is high, and thus a low surface resistance can be maintained, high strength and high permeability Can be provided.

Hereinafter, the present invention will be described.

One. Conductive film  Composition for forming

The composition for forming a conductive film of the present invention (hereinafter, referred to as a "composition") includes metal nanowires; bookbinder; Ultraviolet stabilizer; And inorganic oxides.

The metal nanowires included in the composition of the present invention serve to impart conductivity to the composition. Such metal nanowires are not particularly limited, but they are preferably at least one selected from the group consisting of silver nanowires having high electrical conductivity and high electrical stability, gold nanowires, and platinum nanowires.

The diameter of the metal nanowires is not particularly limited, but is preferably 20 nm or less, more preferably 10 to 20 nm. When the diameter of the metal nanowire exceeds 20 nm, milky phenomenon occurs and the visibility of the display on which the conductive film is applied may be reduced.

The content of the metal nanowires is not particularly limited, but is preferably 0.05 to 0.2 parts by weight based on 100 parts by weight of the composition. If the content of the metal nanowires is less than 0.05 parts by weight, the conductivity of the composition may be deteriorated. If the content of the metal nanowires exceeds 0.2 parts by weight, the composition may be used more than necessary.

The binder included in the composition of the present invention serves as a matrix for fixing metal nanowires dispersed and interconnected. Such a binder is not particularly limited, but is preferably a cellulose-based polymer. When the cellulose-based polymer is used as a binder, the conductive film can serve as a constant viscosity maintaining and fixing matrix within a range of maintaining a high transmittance.

The cellulose-based polymer is not particularly limited, but is preferably at least one selected from the group consisting of methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose, nitrocellulose and carboxymethyl cellulose.

The content of such a binder is not particularly limited, but is preferably 0.05 to 1 part by weight based on 100 parts by weight of the composition. If the content of the binder is less than 0.05 part by weight, dispersion and interconnectivity of the metal nanowire may be deteriorated. If the content of the binder is more than 1 part by weight, the yellow index value of the conductive film may increase, have.

The ultraviolet stabilizer included in the composition of the present invention enhances ultraviolet stability of the composition. Such ultraviolet stabilizer is not particularly limited, but is preferably a hindered amine light stabilizer (HALS). When the hindered amine compound is used as an ultraviolet stabilizer, oxygen radicals in the conductive film are effectively removed, and the polymer compound in the conductive film is prevented from being deteriorated by light.

The content of such ultraviolet stabilizer is not particularly limited, but is preferably 0.01 to 0.1 parts by weight based on 100 parts by weight of the composition. If the content of the ultraviolet stabilizer is less than 0.01 part by weight, the ultraviolet stability of the composition may be deteriorated. If the amount of the ultraviolet stabilizer is more than 0.1 parts by weight, the sheet resistance may be increased.

The inorganic oxide contained in the composition of the present invention plays a role of absorbing ultraviolet rays. Specifically, the inorganic oxide absorbs ultraviolet rays having intrinsic wavelengths possessed by the inorganic oxide, so that the polymer compound and the base material (for example, PET) in the conductive film can be prevented from being optically dissociated by ultraviolet rays. In addition, the presence of the oxygen radical in the conductive film is minimized, and the oxidation of the metal nanowires included in the conductive film can be prevented.

The average particle size (D ₅₀ ) of the inorganic oxide is 20 nm or less, preferably 5 to 20 nm. If the average particle size of the inorganic oxide exceeds 20 nm, the Milky characteristic of the conductive film may be deteriorated.

The inorganic oxide is not particularly limited, but is preferably at least one selected from the group consisting of titanium dioxide, zinc oxide, zirconium oxide, cerium oxide, magnesium oxide, talc, kaolin, tungsten trioxide and perovskite type metal oxides.

The content of such an inorganic oxide is not particularly limited, but is preferably 0.05 to 0.1 parts by weight. If the content of the inorganic oxide is less than 0.05 part by weight, the strength and transparency of the conductive film may be lowered. If the content is more than 0.1 part by weight, the workability and moldability of the conductive film may be lowered.

The composition of the present invention may further include at least one additive selected from the group consisting of a thickener, a surface tension modifier, and an adhesion promoter in order to improve the physical properties thereof. The content of such an additive is not particularly limited, but is preferably 0.005 to 0.1 part by weight based on 100 parts by weight of the composition.

Specifically, the thickener enhances the viscosity of the composition to improve the coating property of the composition. These thickeners may be those known in the art.

The surface tension regulator enhances the coatability of the composition to improve the moldability of the conductive film. Such surface tension regulators are not particularly limited, but fluorine-based compounds (fluorine surfactants) such as perfluoroalkyl carboxylates, perfluorinated sulfonates, perfluorinated sulfates and perfluorinated phosphates can be mentioned.

The content of the surface tension modifier is not particularly limited, but is preferably 0.001 to 0.01 part by weight based on 100 parts by weight of the composition. If the content of the surface tension regulator is less than 0.001 part by weight, the surface tension of the composition may be high and the formability of the conductive film may be deteriorated. If the amount is more than 0.01 part by weight, the effect of controlling the bubble formation of the composition may be deteriorated, .

The adhesion promoter serves to enhance the adhesion between the substrate and the conductive film when the conductive film is formed by coating the composition on the substrate. The adhesion promoting agent is not particularly limited, and examples thereof include an epoxy resin, an acrylic resin, and a urethane resin.

The content of the adhesion promoting agent is preferably 0.005 to 0.1 part by weight based on 100 parts by weight of the composition. When the content of the adhesion promoter is less than 0.005 parts by weight, the adhesion between the substrate and the conductive film may be deteriorated. When the content of the adhesion promoter is more than 0.1 parts by weight, the sheet resistance may be increased.

In addition, the composition of the present invention may further contain solvents, stabilizers, dispersants, reducing agents, wetting agents, antifoaming agents, coupling agents and the like known in the art within a range not affecting the physical properties thereof.

2. Conductive film

The present invention provides a conductive film made from the composition described above.

The method for preparing the conductive film of the present invention is not particularly limited, but may be prepared by coating the substrate with the above-mentioned composition and drying.

The substrate to which the composition is coated is not particularly limited, but may be a polyimide (PI), a polyethylene terephthalate (PET), a polyethersulfone (PES), a nylon, a polytetrafluoroethylene (PTFE) (PEEK), polycarbonate (PC), polyarylate (PAR), and the like; Or a glass substrate.

The method of coating the composition on the substrate is not particularly limited, and a method of coating the composition on the substrate is not particularly limited, and examples thereof include a bar coating, a spin coating, a roll coating, a spray coating, a dip coating, an inkjet printing, , Pad printing, gravure printing, flexography printing, stencil printing, imprinting, and the like.

Conditions for drying the composition coated on the substrate are not particularly limited, but the drying temperature may be 100 to 120 ° C, and the drying time may be 3 to 7 minutes.

The thickness of the conductive film thus produced is not particularly limited, but is preferably 100 to 200 nm.

Since the conductive film according to the present invention is made of a composition having excellent conductivity and transparency as well as excellent stability against ultraviolet rays, it can be applied to various electric and electronic devices, and in particular, as a transparent electrode included in a large- Can be usefully applied.

Hereinafter, the present invention will be described in detail with reference to examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

[ Example  1 to 3]

The components shown in Table 1 were mixed for about 30 minutes using a vortex mixer to prepare a composition for forming a conductive film.

Next, # 12 The composition for forming a conductive film was coated on a PET substrate using a bar coater and dried at 120 ° C for 5 minutes to prepare a conductive film.

ingredient Example 1 Example 2 Example 3 Metal nanowire The nanowire
(Particle size: 15 nm) 0.2 0.2 0.2 bookbinder Hydroxypropylmethylcellulose 0.2 0.2 0.2 Ultraviolet stabilizer Hindered Amine Light Stabilizer 0.05 0.05 0.05 Inorganic oxide ZnO with a particle diameter of 20 nm 0.05 - - ZnO with a particle diameter of 10 nm - 0.05 - TiO _{2 having a} particle diameter of 20 nm - - 0.05 Surface tension agent Fluorine compound 0.05 0.05 0.05 menstruum Deionized water (DIW) Honey. Honey. Honey. Total (parts by weight) 100 100 100

[ Comparative Example  1 to 3]

Except that the composition for forming a conductive film having the composition shown in the following Table 2 was applied, a conductive film was prepared.

ingredient Comparative Example 1 Comparative Example 2 Comparative Example 3 Metal nanowire The nanowire
(Particle size: 15 nm) 0.2 0.2 0.2 bookbinder Hydroxypropylmethylcellulose 0.2 0.2 0.2 Ultraviolet stabilizer Hindered Amine Light Stabilizer - - 0.05 Inorganic oxide ZnO having a particle diameter of 40 nm - 0.05 0.05 Surface tension agent Fluorine compound 0.05 0.05 0.05 menstruum Deionized water (DIW) Honey. Honey. Honey. Total (parts by weight) 100 100 100

[ Experimental Example ]

The properties of the conductive film thus prepared were evaluated by the following methods. The results are shown in Table 3 below.

1. Resistivity: Measured using an R-CHEK model RC2175 surface resistivity meter from Electronic Design To Market, Inc. (Toledo, OH) (Ohio Toledo).

2. Adhesion: Using a Elcometer 1542, a cross cut was made on the conductive film, followed by a Nitodenko # 31b tape. After that, the sheet resistance change before and after the tape adhesion was compared and analyzed using a sheet resistance meter.

3. Pencil hardness: The pencil hardness meter MT-PC1 manufactured by M-Tech Co., Ltd. was used to check whether a conductive film was scratched or not.

4. Transmittance: Measured using NDH5000 from NIPPON DENSHUKU.

     Sample Sheet resistance (ohm / sq.)   Adhesiveness    Pencil hardness    Permeability Before UV irradiation After UV irradiation (480h) Increase rate of sheet resistance (%) Example 1 29 35 20 Good 2H 88.9 Example 2 30 34 13 Good 2H 89.0 Example 3 31 37 19 Good 2H 88.8 Comparative Example 1 36 66 83 Good HB 89.0 Comparative Example 2 34 71 108 Bad H 88.5 Comparative Example 3 30 48 60 Good H 88.4

Referring to Table 3, it can be seen that the conductive film made of the composition for forming a conductive film of the present invention has a low increase rate of sheet resistance and excellent adhesion, pencil hardness, and transparency.

Claims (12)

Metal nanowires; bookbinder; Ultraviolet stabilizer; And an inorganic oxide,
Wherein the inorganic oxide has an average particle size (D ₅₀ ) of 20 nm or less. The method according to claim 1,
Wherein the inorganic oxide is at least one selected from the group consisting of titanium dioxide, zinc oxide, zirconium oxide, cerium oxide, magnesium oxide, talc, kaolin, tungsten trioxide and perovskite type metal oxides. The method according to claim 1,
Wherein the metal nanowires are at least one selected from the group consisting of silver nanowires, gold nanowires, and platinum nanowires. The method according to claim 1,
Wherein the metal nanowires have a diameter of 20 nm or less. The method according to claim 1,
Wherein the binder is a cellulose-based polymer. The method of claim 5,
Wherein the cellulose polymer is at least one selected from the group consisting of methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, hydroxypropylmethylcellulose, nitrocellulose, and carboxymethylcellulose. The method according to claim 1,
Wherein the ultraviolet light stabilizer is a hindered amine compound (HALS). The method according to claim 1,
Wherein the composition further comprises at least one additive selected from the group consisting of a thickener, a surface tension modifier, and an adhesion promoter. The method of claim 8,
Wherein the surface tension regulator is a fluorine-based compound. The method of claim 8,
0.05 to 0.2 parts by weight of the metal nanowire;
0.05 to 1 part by weight of the binder;
0.01 to 0.1 parts by weight of the ultraviolet stabilizer;
0.05 to 0.1 parts by weight of the inorganic oxide; And
And 0.005 to 0.1 part by weight of the additive. A conductive film produced from the composition for forming a conductive film according to any one of claims 1 to 10. The method of claim 11,
Wherein the conductive film is a transparent electrode included in the display.