TW201920509A - Coating composition, conductive film, touch panel and manufacturing method improving touch panel performances such as touch detection sensitivity, operation reliability, and stability - Google Patents

Abstract

Disclosed is to improve touch panel performances such as touch detection sensitivity, operation reliability, stability, etc. of a touch panel. Solution provided in the disclosed is a coating composition comprising chain-like conductive inorganic particles, a binder, a high boiling point solvent, and a low boiling point solvent, wherein the content of the chain-like conductive inorganic particles of the coating composition is 10 to 70% by mass with respect to the total amount of the chain-like conductive inorganic particles and the binder; the coating composition is used in: forming a conductive film on the surface of the touch panel substrate on which an electrode pattern is presented in a touch panel having a TFT substrate, a liquid crystal layer, a color filter substrate, and a touch panel substrate stacked sequentially between two polarizing plates.

Description

Coating composition, conductive film, touch panel and manufacturing method

The present invention relates to a coating composition for forming a conductive film, and particularly to a coating composition for forming a conductive film of a touch panel.

In the past, among the types of liquid crystal display panels, a vertical electric field method typified by a TN (twisted nematic) type has been dominant, but a liquid crystal display panel recently called a lateral electric field method has also become mainstream. The liquid crystal display panel of the horizontal electric field method has the advantage of a wider viewing angle than the vertical electric field method, but has a problem that does not occur in the liquid crystal display panel of the vertical electric field method. It has a liquid crystal display panel that is affected by static electricity from the outside or inside. Or external electromagnetic interference, light leakage occurs during black display, and the problem of display quality degradation. This is because the liquid crystal display panel of the transverse electric field type has a structure in which display electrodes and reference electrodes are accumulated on a transparent substrate on one side. Therefore, it becomes a conductive layer having no shielding function against static electricity from the outside at all. Composition.

In order to solve the problem of such a panel structure in the transverse electric field method, it has been proposed to form a transparent substrate of a liquid crystal display panel with a transparent substrate on a side of the transparent substrate farther from the backlight unit than the liquid crystal layer. The technology of an optically conductive layer and having an electrostatic discharge (ESD) function is specifically a method of forming an antistatic film containing ITO or the like as a conductive layer.

In addition, various types of touch panels are proposed based on the principle of detecting the position on the touch panel sensor. In smart phones, from the point of view of optically bright and simple structure, the electrostatic capacity method is mostly used. The principle is a mechanism that detects the position of an object by a new parasitic capacity occurring through a dielectric body contacting the touch panel sensor layer through a dielectric body that should detect the position.

Recently, as represented by a liquid crystal display device used in a smart phone or the like, the need for a liquid crystal display device using a touch liquid crystal display panel has increased. In one example of a touch liquid crystal display panel, there is a so-called on-cell type touch panel. The cell-type touch panel is a built-in liquid crystal display panel with a touch panel function, and has a layer structure in which a touch detection electrode is laminated between a color filter substrate and an upper polarizing plate.

Patent Document 1 describes a structure of a built-in liquid crystal display panel with a touch panel function. The touch panel shown in FIG. 6 of Patent Document 1 includes a TFT array substrate 21, a touch panel driving electrode COML, a liquid crystal layer 6, and a color filter, which are sequentially laminated between two polarizing plates 4, 54. A layer structure of the light sheet 32, the touch detection electrode CB1, the protective layer 33, the adhesion layer 51, the conductive layer 52, and the cover layer 53.

The conductive layer 52 has a conductive function and is electrically connected to the TFT array substrate. As a result, the conductive layer 52 reduces image display disturbance when static electricity is applied to the surface of the polarizing plate 5. Alternatively, the conductive layer 52 prevents or suppresses a decrease in touch detection sensitivity when static electricity is applied to the surface of the polarizing plate 5.

A cell-type touch panel is used in a liquid crystal display device requiring high quality because of its excellent sensitivity. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2016-4183

[Problems to be Solved by the Invention]

As for the touch panel, as the display performance of the liquid crystal display panel is improved, it is required to further improve the touch panel performance such as touch detection sensitivity, motion reliability, and stability. [Means for solving problems]

The invention provides a coating composition, which is a coating composition including chain-shaped conductive inorganic particles, a binder, a high-boiling point solvent and a low-boiling point solvent. The coating composition is relative to the chain-shaped conductive inorganic particles and The total amount of the binder is 10 to 70% by mass of the chain-shaped conductive inorganic particles. It is used for a TFT substrate, a liquid crystal layer, and a color filter that are sequentially laminated between two polarizing plates. In a touch panel of a substrate and a touch panel substrate, the use of a conductive film is formed on a surface on which an electrode pattern of the touch panel substrate exists.

In a certain aspect, the coating composition contains a solid component composed of the chain-shaped conductive inorganic particles and the binder in an amount of 0.1 to 5.0% by mass, and has a viscosity of 7.0 mPa · s or less.

In a certain aspect, the aforementioned chain-shaped conductive inorganic particles are formed by connecting 2 to 50 primary particles having a particle diameter of 2 to 30 nm.

In a certain aspect, the chain-shaped conductive inorganic particles include at least one particle selected from the group consisting of antimony-containing tin oxide particles, tin-containing indium oxide particles, and phosphorus-containing tin oxide particles.

In one form, the aforementioned touch panel is a touch panel having a second touch panel substrate laminated between a TFT substrate and a color filter substrate.

The present invention also provides a conductive film for a touch panel having a TFT substrate, a liquid crystal layer, a color filter substrate, and a touch panel substrate that are sequentially laminated between two polarizing plates. The upper surface of the substrate is formed using the coating composition as described above.

In one embodiment, the conductive film has a film thickness of 2 to 100 nm.

In one embodiment, the conductive film has a surface resistance of 1.0 × 10 ⁹ to 1.0 × 10 ¹⁴ W / □ or more.

In one form, the conductive film has a pencil hardness of 3H to 9H.

In one form, the aforementioned touch panel is a touch panel having a second touch panel substrate laminated between a TFT substrate and a color filter substrate.

The present invention also provides a touch panel including a TFT substrate, a liquid crystal layer, a color filter substrate, a touch panel substrate, and any one of the foregoing conductive films laminated in order between two polarizing plates.

In one form, the aforementioned touch panel is a touch panel having a second touch panel substrate laminated between a TFT substrate and a color filter substrate.

In addition, the present invention provides a method for forming a conductive film, which includes a TFT substrate, a liquid crystal layer, a color filter substrate, and a touch panel substrate which are sequentially laminated between two polarizing plates. In a touch panel, a step of applying a coating composition on a surface where an electrode pattern of the touch panel substrate exists and drying the coating composition. The coating composition includes chain-shaped conductive inorganic particles, a binder, and a high boiling point. The content of the solvent and the low-boiling-point solvent relative to the total amount of the chain-shaped conductive inorganic particles and the binder is 10 to 70% by mass, and the coating is performed by a spray method. [Effect of the invention]

According to the present invention, it is possible to provide a coating composition and a conductive film that can improve the touch panel performance such as the touch detection sensitivity of the touch panel and the stability with time. In addition, according to the present invention, a touch panel having improved touch panel performance such as touch detection sensitivity, motion reliability, and stability can be provided.

[Mode for Carrying Out the Invention]

The touch panel to which the coating composition of the present invention is applied is an electrostatic capacity type touch panel that detects an electrostatic capacity that changes according to the capacity of an object approaching or contacting an electrode. In addition, the liquid crystal display device with a touch detection function using the touch panel is a transverse electric field type liquid crystal provided with a detection electrode for touch detection on any one of a TFT substrate and a counter substrate forming the display device. Display device.

(Coating composition) First, the coating composition of this embodiment will be described.

The coating composition of this embodiment contains chain-shaped conductive inorganic particles, a binder, a high-boiling point solvent, and a low-boiling point solvent. The content of the chain-shaped conductive inorganic particles is 10 to 70% by mass based on the total amount of the chain-shaped conductive inorganic particles and the binder.

By using the above-mentioned coating composition, a conductive film having high ESD performance without reducing touch sensitivity and having excellent light transmittance and hardness can be provided.

<Chain conductive inorganic particles> ＞ The coating composition of this embodiment is based on the total amount of the chain conductive inorganic particles and the binder, and the content of the chain conductive inorganic particles is set to 10 to 70% by mass, and can provide a conductive film with high ESD performance without reducing touch sensitivity. When the content of the chain-shaped conductive inorganic particles is less than 10% by mass, the ESD function of the conductive film is reduced. When the content of the chain-shaped conductive inorganic particles exceeds 70% by mass, the touch sensitivity is reduced. The content of the chain-shaped conductive inorganic particles is preferably 12 to 62% by mass, more preferably 14 to 43% by mass, and even more preferably 15 to 34% by mass relative to the total amount of the chain-shaped conductive inorganic particles and the binder. %.

In addition, by using the above-mentioned chain-shaped conductive inorganic particles, the conductivity of the conductive film can be improved by a smaller amount than when the non-chain-shaped conductive inorganic particles are used. It is thought that this is because the inorganic particles have a chain structure, and the conductive network between the inorganic particles is increased more than when the inorganic particles exist alone, and the conductivity of the entire conductive film is increased. Therefore, since the amount of inorganic particles used to achieve specific conductivity of the conductive film can be reduced, the light transmittance of the conductive film can also be increased.

The above-mentioned chain-shaped conductive inorganic particles are chain-shaped secondary particles in which primary particles are connected. The so-called primary particles mean particles that exist alone, and the so-called secondary particles mean particles that have two or more primary particles. Specifically, it is preferable that the chain-shaped conductive inorganic particles are formed by connecting 2 to 50 particles using primary particles having a particle diameter of 2 to 30 nm, and more preferably are formed by connecting 3 to 20 particles. When the number of primary particles having the above-mentioned particle size exceeds 50, the haze value of the conductive film tends to increase due to scattering of the particles. If the number of primary particles having the above-mentioned particle size is less than two, the particles become non-chain and the formation of a conductive network between the inorganic particles becomes difficult, and the conductivity of the conductive film decreases.

The particle diameter and the number of connections are, for example, a coating composition that can be diluted with a low-boiling solvent, and coated on various substrates with a film thickness of 2 to 10 nm to form a conductive film, and observed by a transmission electron microscope (TEM) The particle diameter and the number of connections of each particle constituting the chain-shaped conductive inorganic particles were measured and determined.

The chain-shaped conductive inorganic particles are not particularly limited as long as they are chain-shaped particles having both transparency and conductivity. For example, metal particles, carbon particles, conductive metal oxide particles, and conductive nitride particles can be used. . Among these, conductive metal oxide particles having both transparency and conductivity are preferred. Examples of the conductive metal oxide particles include tin oxide particles, antimony oxide particles, antimony-containing tin oxide (ATO) particles, tin-containing indium oxide (ITO) particles, phosphorus-containing tin oxide (PTO) particles, Metal oxide particles such as aluminum-containing zinc oxide (AZO) particles, gallium-containing zinc oxide (GZO) particles, and the like. The conductive metal oxide particles may be used alone or in combination of two or more. The chain-shaped conductive inorganic particles preferably include at least one selected from the group consisting of ATO particles, ITO particles, and PTO particles. These conductive inorganic particles are excellent in transparency, conductivity, and chemical properties, and can achieve high light transmittance and conductivity even when they are conductive films.

The method for producing the above-mentioned chain-shaped conductive inorganic particles is not particularly limited. For example, Japanese Patent Application Laid-Open No. 2000-196287, Japanese Patent Application Laid-Open No. 2005-139026, Japanese Patent Application Laid-Open No. 2006-339113, and Japanese Patent Laid-Open No. 2012 can be used. The manufacturing method described in -25793.

<Binder> The binder is not particularly limited as long as it can disperse the chain-shaped conductive inorganic particles to form a coating film, and any of an inorganic binder and an organic binder can be used. The content of the binder is preferably 20% by mass or more based on the total amount of the chain-shaped conductive inorganic particles and the binder. If it is less than 20% by mass, the strength of the conductive film tends to decrease.

As the inorganic adhesive, for example, an alkoxysilane can be used. More specifically, the alkoxysilane is preferably a compound in which 3 to 4 alkoxy groups are bonded to silicon, and when dissolved in water, a polymer having a high molecular weight SiO ₂ formed by -OSiO- linkage can be used.

As said alkoxysilane, it is preferable that it is a polyfunctionality containing at least 1 sort (s) chosen from the group which consists of a tetraalkoxysilane, trialkoxysilane, dialkoxysilane, and an alkoxysilane oligomer. Alkoxysilane. The so-called alkoxysilane oligomer refers to a high-molecular-weight alkoxysilane formed by condensing monomers of alkoxysilane, and has two or more siloxane bonds (- OSiO-). The number of bonds is preferably 2 to 20.

Examples of the above-mentioned tetraalkoxysilanes include carbon number of tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetra-third-butoxysilane, etc. A silane substituted by an alkoxy group of 1 to 4;

Examples of the trialkoxysilane include trimethoxysilane, triethoxysilane, tripropoxysilane, tributoxysilane, triisopropoxysilane, and tri-L-butoxysilane The silanes substituted by alkoxy groups having 1 to 4 carbon atoms, such as "KBM-13 (methyltrimethoxysilane)", "KBE-13 (methyltriethoxysilane)", etc. Silane substituted by alkyl.

Examples of the dialkoxysilane include processes such as dimethyldimethoxysilane, diphenyldimethoxysilane, dimethyldiethoxysilane, and diphenyldiethoxysilane. Part of the silanes substituted by alkoxy groups having 1 to 4 carbon atoms, "KBM-22 (dimethyldimethoxysilane)", "KBE-22 (dimethyldiethoxysilane)", etc. Silane substituted by alkyl.

As an example of the said alkoxysilane oligomer, the alkoxysilane oligomer which has a comparatively low molecular weight which has both an organic group and an alkoxysilyl group is mentioned. Specific examples include "X-40-2308", "X-40-9238", "X-40-9247", "KR-401N", "KR-510", and "KR" manufactured by Shin-Etsu Chemical Co., Ltd. -9218 "," Ethyl Silicate 40 "," Ethyl Silicate 48 "," Methyl Silicate 51, "Methyl Silicate 53A", etc. "manufactured by COLCOAT.

Among the specific examples of the above-mentioned alkoxysilane, in order to form a conductive film having a higher hardness, it is preferable to use a combination of tetraalkoxysilane, tetraalkoxysilane, and trialkoxysilane, and a part of the Take trialkoxysilane or dialkoxysilane, and the alkoxysilane oligomer whose functional group is alkoxysilyl. This is because by using these, the hardness of the conductive film is strengthened by promoting the three-dimensional cross-linking of the siloxane bond between the molecules of the adhesive, which can further eliminate the occurrence of turtles in the conductive film due to changes over time. The risk of cracking can further improve the adhesion to the substrate.

Furthermore, in order to form a good-quality film with good reproducibility in a more stable state, it is preferable to use a hydrolyzation reaction of an alkoxysilane with respect to the coating composition and use it in a silanolized state. Examples of the adjustment method include a method of adding water and an acid catalyst to an alkoxysilane diluted with a low-boiling point solvent such as alcohol, and silicifying it in advance, or a conductive coating composition. Add water and acid catalyst to make it silanolized. The content of water is determined from the structure of the alkoxysilane, and the theoretical value is obtained. However, it is appropriately adjusted according to the pot life of the coating composition, the coating adaptability, and the physical characteristics of the conductive film. The content of the water is preferably 50 to 1500% by mass based on the entire amount of the alkoxysilane. This is because if it is less than 50% by mass, the strength of the conductive film is reduced, and if it exceeds 1500% by mass, the drying speed is slowed down and the coating adaptability is affected.

Examples of the organic binder include acrylic resin, polyester resin, polyamide resin, polycarbonate resin, polyurethane resin, polystyrene resin, polyvinyl chloride resin, and polyvinylidene chloride. Dichloroethylene resin, polyvinyl alcohol resin, polyvinyl acetate resin, and photopolymerizable resin containing a photopolymerizable monomer and a polymerization initiator.

The photopolymerizable monomer is preferably a tri-functional or higher (meth) acrylic monomer containing 50 to 90%. Here, the content rate of a photopolymerizable monomer means the mass ratio of a photopolymerizable monomer with respect to the total mass of a photopolymerizable monomer and a polymerization initiator. By polymerizing and curing (meth) acrylic monomer having many reaction points to form a matrix resin, the strength of the conductive film can be further increased. When the mass ratio of the trifunctional or more photopolymerizable monomer is less than 50%, the hardness of the coating film becomes weak, and the durability decreases. In addition, since it is necessary to use a polymerization initiator together with the photopolymerizable monomer, it is substantially difficult to make the mass ratio of the photopolymerizable monomer exceed 90%.

Examples of the trifunctional (meth) acrylic monomer include trimethylolpropane tri (meth) acrylate. Pentaerythritol tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate; examples of tetrafunctional or higher (meth) acrylic monomers include pentaerythritol tetraacrylate, dipentaerythritol pentaerythritol Acrylate, dipentaerythritol hexaacrylate, etc. In addition, as the photopolymerizable monomer, a commercially available polyfunctional acrylic oligomer may be used. Particularly preferred is one having high hardenability and high hardness. Examples include "AH-600" manufactured by Kyoeisha Chemical Co., Ltd., "UA-306H" or "NK Oligo U-6HA" and "NK Oligo U-15HA" manufactured by Shin Nakamura Chemical Co., Ltd.

Moreover, the said photopolymerizable monomer may contain monofunctional and bifunctional photopolymerizable monomer, For example, a 1, 4- butanediol di (meth) acrylate, neopentyl glycol di (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, ethoxylated bisphenol A di (meth) acrylic acid Esters, bifunctional polymerizable monomers such as cyclohexanedimethanol di (meth) acrylate; vinyl monomers such as vinyl pyrrolidone, vinylformamide, butyl (meth) acrylate, ( (Meth) acrylic acid alkyl (meth) acrylates such as 2-ethylhexyl acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, alicyclic (meth) acrylates, ( (Meth) hydroxyethyl methacrylate, hydroxypropyl (meth) acrylate, etc.Hydroxy (meth) acrylate, acrylamidomorpholine, dimethylaminoethyl (meth) acrylate, etc. Monofunctional aromatic (meth) acrylates such as nitrogen (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, tetrahydrofurfuryl acrylate, etc. Polymerizable monomer.

Examples of the polymerization initiator include a-diketones such as diphenylethylenedione and diethylfluorene, acetophenones such as benzoin, benzoin methyl ether, and benzoin ethyl Ethers, acetoin isopropyl ethers, etc., thioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, thioxanthone-4-sulfonic acid Ketones, diphenyl ketones, 4,4'-bis (dimethylamino) diphenyl ketones, 4,4'-bis (diethylamino) diphenyl ketones, and other diphenyl ketones , Michelin, acetophenone, 2- (4-toluenesulfonyloxy) -2-phenylacetophenone, p-dimethylaminoacetophenone, a, a'-dimethoxy Ethyloxydiphenyl ketone, 2,2'-dimethoxy-2-phenylacetophenone, p-methoxyacetophenone, 2-methyl-1- [4- (methylthio) Phenyl] -2-morpholinylpropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinylphenyl) -but-1-one, and the like Quinones, anthraquinone, 1,4-naphthoquinone, acetophenone chloride, trihalomethylphenylhydrazone, ginseng (trihalomethyl) -s-tri And the like, halogen compounds, fluorenylphosphine oxides, peroxides such as di-tert-butyl peroxide, and the like.

The photopolymerizable monomer and the polymerization initiator may be used alone or in combination of two or more kinds.

<High boiling point solvent> As the high boiling point solvent, as long as it can dissolve the binder component and can be removed by the drying step after coating, for example, ethylene glycol, dimethylarsine, and N-formaldehyde can be used. Methylpyrrolidone, N-ethylpyrrolidone, N-methylformamide, 1,2-propanediol, N, N-dimethylaniline, cresol, nitrobenzene, ethylene glycol, and the like. The high-boiling-point solvent is preferably an organic-based or inorganic-based solvent having a boiling point of 120 ° C or higher.

The content of the high boiling point solvent may be about 0.1 to 30.0% by mass based on the total amount of the conductive coating composition.

<Low boiling point solvent> As the low boiling point solvent, for example, ethanol, methanol, n-propanol, isopropanol, n-butanol, isobutanol, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, and acetone can be used. ,two Alkane, ethyl acetate, chloroform, acetonitrile, pyridine, acetic acid, water, etc. By using the low-boiling-point solvent, the dispersibility of the chain-shaped conductive inorganic particles is improved. Low-boiling solvents are preferably organic and inorganic solvents having a boiling point of less than 120 ° C.

The content of the low boiling point solvent may be about 50.0 to 99.5% by mass based on the entire amount of the conductive coating composition.

<Acid Catalyst> In the coating composition of the present invention, a commonly used acid catalyst (hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid, etc.) may be further added. This makes it possible to form a high-quality conductive film with more stable performance and good reproducibility. The content of the acid catalyst may be about 1.0 to 30.0% by mass based on the total amount of the alkoxysilane.

<Leveling agent> A leveling agent may be further added to the coating composition of the present invention. Thereby, the surface smoothness of a conductive film can be ensured. As the leveling agent, for example, polyether modified polydimethylsiloxane, dipropylene glycol monomethyl ether, or the like can be used. The content of the leveling agent catalyst may be about 0.01 to 5.0% by mass based on the entire amount of the conductive coating composition.

<Preparation method> The preparation method of the coating composition of the present invention is not particularly limited as long as the above-mentioned components can be mixed and the chain-shaped conductive inorganic particles are dispersed in the binder and the solvent. Each component can be processed by mechanical treatment of permeating media such as ball mills, sand mills, hand mills, paint conditioners, etc., or by using ultrasonic dispersers, homogenizers, dispersers, and jet mills to perform dispersion treatment. Mix and disperse.

The coating composition-based solid content concentration of the present invention after the above preparation is 0.1 to 5.0% by mass based on the entire amount. The solid content of the coating composition is typically the total amount of the chain-shaped conductive inorganic particles and the binder. If the solid content concentration of the coating composition is less than 0.1% by mass, in order to control the thickness of the conductive film to an appropriate range and increase the coating amount, the transfer from the wet film to the dry film during the drying process takes time and process. Not practical. In addition, if it exceeds 5.0% by mass, the coating amount decreases, so the thickness of the wet film becomes insufficient, the leveling agent performance cannot be exhibited, and variations in the substrate occur in the film characteristics such as surface resistance. The solid content concentration of the coating composition is preferably 0.3 to 3.0% by mass, and more preferably 0.5 to 2.0% by mass.

The viscosity of the coating composition of the present invention is preferably 50 mPa · s or less. If the viscosity of the coating composition exceeds 50 mPa · s, the atomization of the spray composition is not performed properly, the spray droplets are too large, or the particle size distribution of the spray droplets is excessively uneven. As a result, among the characteristics of the film such as surface resistance, the characteristics within the substrate are deviated, or the appearance of the film is deteriorated. The viscosity of the coating composition is preferably 25 mPa · s, and more preferably 7.0 mPa · s or less.

(Conductive film) Hereinafter, the conductive film of the present invention will be described.

The conductive film of the present invention is formed by applying the coating composition of the present invention to a touch panel substrate 9 described later to form a coating film, drying the coating film, and curing the film if necessary.

As the coating method of the coating composition, a spray method is preferably used. The object to be coated is the touch panel substrate 9, and an electrode pattern 92 exists on the substrate, that is, a pattern-shaped convex portion exists on the surface of the object to be coated. Therefore, by using the spraying method, a uniform film can be formed on the entire surface of the electrode substrate 91 and the electrode pattern 92.

As the coating conditions using the spraying method, the diameter of the spray gun is preferably 0.5 to 3.0 mm, the needle opening is 0.05 to 0.30 mm, the amount of liquid to be discharged is 0.10 to 3.00 g / min, and the minimum distance between the spray gun and the substrate is 50 to 300mm, coating speed is 100-2000mm / sec, overlap pitch is 2-30mm, pressure of atomizing air is 0.05-0.50MPa. As the number of spray guns, in addition to the use of a single gun, from the viewpoint of coating efficiency, it is appropriate to arrange a plurality of guns in accordance with the size of the substrate.

After the coating composition is coated on the electrode substrate 91, the solvent is removed by drying to form a film. If necessary, the coating film may be irradiated with UV light or EB light to harden the coating film. For example, by using the coating composition and spraying method of the present invention, the coating film of the coating film is dried and hardened if necessary, and the formed film is a conductive spray film.

The surface resistance of the conductive film of the present invention is 1.0 × 10 ⁹ to 1.0 × 10 ¹⁴ W / □. If the surface resistance of the conductive film does not reach 11.0 × 10 ⁹ W / □, the touch sensitivity decreases, and if it exceeds 1.0 × 10 ¹⁴ W / □, the antistatic performance decreases. The surface resistance of the conductive film is preferably 1.0 × 10 ⁹ to 1.0 × 10 ¹³ W / □, and more preferably 7.0 × 10 ¹⁰ to 5.0 × 10 ¹² W / □.

The conductive film of the present invention has a surface resistance of 1.0 × 10 ⁹ to 1.0 × 10 ¹⁴ W / □ after being held for 500 hours under an environment of a temperature of 65 ° C. and a relative humidity of 90%, preferably 1.0 × 10 ⁹ to 1.0 × 10 ¹³ W / □, more preferably 7.0 × 10 ¹⁰ to 5.0 × 10 ¹² W / □. In addition, in order to provide a conductive film that has high ESD performance after the reliability test and does not reduce the touch sensitivity, the change in surface resistance before and after reliability is relatively small even if it changes on either the falling side or the rising side. It is preferably in the range of 1.0 power W / □, and more preferably in the range of 0.5 power W / □.

The thickness of the conductive film of the present invention is 2 to 100 nm. If the thickness of the conductive film is less than 2 nm, the smoothness of the surface of the film is impaired because the size of the primary particles is less than the primary particle size. If it exceeds 100 nm, the total light transmittance of the film is deteriorated. The thickness of the conductive film is preferably 5 to 80 nm, and more preferably 10 to 60 nm.

The hardness of the conductive film pencil of the present invention is 3H-9H, preferably 4H-7H, and more preferably 5H-6H.

The total light transmittance (based on JIS K7105) of the conductive film of the present invention is 95.0% or more, and preferably 97.0 to 99.9%.

Moreover, the touch panel is generally divided into a small substrate from a large substrate with a diamond cutter in a panel manufacturing step. Therefore, when the conductive film of the present invention is cut together with a glass substrate, it is preferable that no adherence occurs on the cutter and a smooth cut surface is provided.

<Touch panel> (1) A touch panel to which the coating composition of the present invention is applied is a type of touch panel having a layer structure in which a touch panel substrate is laminated on a color filter substrate. As such a touch panel, a cell-type touch panel is typically exemplified. The touch panel to which the coating composition of the present invention is applied may have a second touch panel substrate. The second touch panel substrate may be laminated at an appropriate position between the color filter substrate and the upper polarizing plate, or may be laminated at an appropriate position between the TFT substrate and the color filter substrate.

FIG. 1 is a cross-sectional view showing a structure of a cell-type touch panel according to an embodiment of the present invention. The display area of the on-cell touch panel 1 is represented by Ad, and the non-display area is represented by As. Generally, the peripheral region As is an upper region of the substrate 21 and is a region located on the outer peripheral side of the substrate 21 than the display region Ad.

The cell-type touch panel 1 has the following elements laminated between the lower polarizing plate 2 and the upper polarizing plate 3. That is, the TFT substrate 4, the common electrode 5, the insulating film 6, the liquid crystal display panel 7 (consisting of the pixel electrode 71, the liquid crystal layer 72, and the sealing portion 73), the color filter substrate 8, and the touch panel substrate 9 (consisting of Electrode substrate 91, electrode pattern 92). The conductive film 10 and the adhesive layer 11. An adhesive layer 12 and a cover glass 13 are laminated on the upper polarizing plate 3.

In addition, the so-called "lamination" in the description of this case means that the layers are in a state of overlapping. The layers to be laminated may be, for example, by having another layer therebetween without contacting each other.

The electrode pattern 92 constituting the touch panel substrate 9 is composed of conductive lines provided on the electrode substrate 91. The thickness of the conductive wire is generally several μm, for example, 5 μm. The pattern shape of the electrode pattern 92 is generally a sawtooth shape or a mesh shape in a planar view. That is, there are convex portions in a pattern on the upper surface of the touch panel substrate 9.

A conductive film 10 is provided on the touch panel substrate 9. When the conductive film 10 is not provided, static electricity is applied from the outside of the cell-type touch panel 1 and, for example, the surface of the polarizing plate 5 is charged. The electric field caused by the static electricity has the liquid crystal molecules of the liquid crystal layer 6 The alignment state is disordered, and the display of the image may be disordered.

On the other hand, by providing the conductive film 10, the static electricity applied from the outside of the unit cell-type touch panel 1 can be escaped to the outside, and the static electricity applied to the unit cell-type touch panel 1 can be reduced. Disturbance of image display.

The conductive film 10 is preferably arranged on the touch panel substrate 9 over the entire area of the display area Ad so as to cover the electrode pattern. The conductive film 10 is formed using the coating composition of the present invention. That is, the conductive film 10 is directly provided on the touch panel substrate without using an adhesive layer.

Thereby, a cell-type touch panel with improved touch panel performance such as touch detection sensitivity, motion reliability, and stability can be provided. Although the reason is not clear, it is considered as follows. Generally, an adhesive is used for the application which follows the component of a touch panel. A strong adhesive force is not required, and the adhesive system obtains a certain adhesive force immediately after bonding.

For example, in the on-cell touch panel of FIG. 6 in Patent Document 1, an adhesive layer 51 is provided between the conductive layer 52 and the conductive pattern CB1. In addition, as another form of the antistatic conductive film, there is a method in which conductive inorganic particles are dispersed in an adhesive layer.

On the other hand, the adhesive is also soft after bonding. Therefore, the elements laminated through the adhesive are not completely fixed in place. For example, after the time elapses after bonding, the adhesive system flows slowly, or when the temperature of the surrounding environment is high, the adhesive system softens and there is a possibility that the position of the adherend changes.

The static electricity applied to the unit cell-type touch panel 1 discharges the TFT substrate through the antistatic conductive film and wiring, but when the lamination system of the antistatic conductive film is performed with an adhesive, the antistatic conductive As the position of the conductive film changes, as a result, the distance between the antistatic conductive conductive film and the TFT substrate also changes, so the conductivity changes. Moreover, in the antistatic conductive film in which conductive inorganic particles are dispersed in the adhesive layer, the position of the conductive inorganic particles in the adhesive layer changes, and the conductivity changes.

In contrast, when the conductive film of the present invention is formed on a touch panel substrate, no adhesive is used. The conductive film of the present invention has a pencil hardness of 3H to 9H. Therefore, the conductive inorganic particles are fixed in the conductive film, and the distance between the conductive film and the TFT substrate does not change. Further, the distance between the conductive film and the TFT substrate is shortened by omitting the adhesive layer, and the conductivity is increased.

As a result, the touch panel of the present invention is considered to have improved touch panel performance such as touch detection sensitivity, motion reliability, and stability.

FIG. 2 is a cross-sectional view schematically showing a layer structure of a cell-type touch panel to which the coating composition of the present invention can be applied. The above cell-type touch panel is shown in FIG. 2a, and may have a second touch panel substrate 9 'laminated between the color filter substrate 8 and the touch panel substrate 9. The second touch panel substrate is shown in FIG. 2b, and may be laminated between the liquid crystal layer 72 and the color filter substrate 8.

FIG. 3 is a cross-sectional view schematically showing a layer structure of an intra-cell type touch panel to which the coating composition of the present invention can be applied. In the intracellular touch panel of FIG. 3, on the TFT substrate 4, a common electrode that also has a touch detection function is laminated, that is, the common electrode and the touch electrode 5 '. The touch panel substrate 9 is laminated between the color filter substrate 8 and the upper polarizing plate. The common electrode and touch electrode 5 'is equivalent to a second touch panel substrate. Even if it is an intra-cell touch panel, as long as the touch panel substrate has a layer structure laminated on a color filter substrate, the touch panel substrate that can be laminated on the color filter substrate The patterned electrode is applied with the coating composition of the present invention. [Example]

Hereinafter, the present invention will be specifically described based on examples. However, the present invention is not limited by the following examples. In addition, the following "parts" and "%" are based on quality unless otherwise specified.

<Chain-shaped antimony-containing tin oxide (ATO) particle dispersion liquid> As a chain-shaped ATO particle dispersion liquid, prepare "ELCOM V-3560" manufactured by Nichiken Chemical Co., Ltd. The chain-shaped ATO particle dispersion "ELCOM V-3560" is a mixed dispersion of chain-shaped ATO particles: 20.8 parts, ethanol: 70.0 parts, and isopropyl alcohol 9.2 parts.

3 and 4 are transmission electron microscope (TEM) photographs of the chain-shaped ATO particles used in the chain-shaped ATO particle dispersion. Referring to FIGS. 2 and 3, it can be seen that the chain-shaped ATO particles (chain-shaped conductive inorganic particles) formed by connecting 2 to 50 primary particles having a particle diameter of 2 to 30 nm in the above-mentioned ATO particle system. Table 1 shows the main materials used in the examples.

(Manufacturing example) <Production of Dispersion Liquid A> A plastic bottle was added with 20.8 parts of conductive ATO particles "SN100P" (trade name) made by Ishihara Sangyo Co., Ltd. and a dispersant "BYK180" made by BYK Chemical Japan (Trade name) 2.0 parts and 77.2 parts of isobutanol (solvent) were dispersed in a paint conditioner (manufactured by Toyo Seiki Co., Ltd.) for 2 hours using zirconia beads having a diameter of 0.3 mm, and then stirred to produce dispersion A.

(Examples 1 to 6 and Comparative Examples 1 to 3) <Manufacturing of coating composition> In a plastic bottle, each component was added in an amount to a specific content, and the coating composition was prepared by stirring. However, the alkoxysilane is diluted with a part of alcohol, and water and an acid catalyst are added to make it silanolized before use.

The viscosity of the obtained coating composition was measured using a TV25 viscometer manufactured by Toki Sangyo Co., Ltd. Tables 2 and 3 show the types, blending amounts, non-volatile solid content and viscosity of the coating composition.

<Manufacturing of a conductive film> A coating film was formed by applying the coating composition by spray coating on a substrate of alkali-free glass having a size of 10 cm square and a thickness of 0.7 mm. In the spraying machine, a spray gun (vortex nozzle, caliber: 1.0 mm) manufactured by NORDSON was used. The coating conditions are as follows. That is, the needle opening degree: 0.10mm, the discharged liquid volume: 0.60g / min, the shortest distance between the spray gun and the substrate: 100mm, the coating speed: 300mm / sec, the overlap distance: 10mm, the pressure of the atomizing air and vortex air: 0.25 MPa. The formed coating film was heated at 120 ° C for 1 hour to prepare a conductive film.

In the case of Example 6, the coating solution of Example 6 was coated on a glass substrate with a sprayer and dried at 80 ° C. for 5 minutes. Then, a high-pressure mercury lamp was used at 300 mJ / cm ² . The amount of light was irradiated with ultraviolet rays to harden, and the conductive film of Example 6 was formed.

Next, the characteristics of the obtained conductive film were tested as described below. The results are shown in Tables 4 and 5.

<Film thickness> 切断 The conductive film was cut together with the glass substrate, and a cross-section observation was performed with a scanning electron microscope (SEM, "S-4500" by Hitachi, Ltd.) to measure the film thickness.

<Surface resistance> The surface resistance of the conductive film was measured using a surface resistance meter ("Hiresta MCP-HT450" manufactured by Mitsubishi Chemical Corporation, applied voltage: 10V), and used as a normal surface resistance.

In addition, the surface resistance of the conductive film after the glass substrate with the conductive film was kept in an environment at a temperature of 65 ° C. and a relative humidity of 500% for 500 hours was measured in the same manner as the surface resistance after the high temperature and high humidity test.

<Total light transmittance> First, the total light transmittance of a glass substrate with a conductive film was measured using a photometer "Hazemeter NDH2000" manufactured by Nippon Denshoku Industries. The numerical value only shows the value of the coating film.

<Pencil hardness> The surface hardness tester "HEIDON-14DR" manufactured by Shinto Scientific was used to measure the pencil hardness of the conductive film.

<Glass Cut-off Property> The glass substrate provided with a conductive film was cut by using a simple cutting knife "Linear Cutter LC200AHH" and a cutting wheel "APIO φ3mm TYPEA" made by Samsung Diamond Industry Co., Ltd., and the glass cut was evaluated. Breaking.

The conditions at the time of cutting are set as follows. That is, the load was repeated 100 times under the conditions of a load of 10 N, a cutting amount of 0.15 μm, and a scribe length of 100 mm. Then, the condition of the wheel attachment and the cut surface was visually confirmed. The evaluation criteria are as follows.

Criteria for evaluating glass cutting properties ○: No adhesion, good cut surface, △: There are few adhesions, and there are few defects on the cut surface, ´: There are adhesions, and there are defects on the cut surface

<Manufacturing of a cell-type touch panel> A liquid crystal display device having a screen size of 4 inches and a total thickness of the liquid crystal display device of 1 mm was manufactured as shown in FIG. 1.

The conductive film is formed on the upper surface of the touch panel substrate, and the coating liquid is applied using a sprayer under the same conditions as described above, and then dried in a dryer at 120 ° C. for 1 hour to form the conductive film. Next, a silver paste ("Dotite D-362" manufactured by Fujikura Kasei Co., Ltd.) was used to attach a ground wire to the end of the conductive film, and then a polarizing plate was attached to the conductive film. In addition, a pixel electrode and a common electrode are provided, and a polarizing plate is also attached to the backlight side of the lower glass substrate.

Next, the touch sensitivity and electrostatic discharge (ESD) performance of each of the above-mentioned liquid crystal display devices were confirmed as follows.

<Touch sensitivity> 触控 Touch the liquid crystal display device with your finger to confirm the touch sensitivity. As a result, the case of the touch of the responding finger was evaluated as ○, and the case of the touch of the non-reactive finger was evaluated as ´.

In addition, the touch sensitivity of the conductive film after the glass substrate with a conductive film was kept at a temperature of 65 ° C. and a relative humidity of 90% for 500 hours was measured in the same manner as above. Control sensitivity.

<ESD properties> (1) After irradiating light from the lower glass substrate side with backlight to confirm that the liquid crystal display device is in a non-energized state and black display, static electricity is applied to the upper glass substrate with a voltage of ± 12 kV using a static electricity applying device. Then, after the ground wire of the conductive film was grounded, a visual confirmation of a non-energized state was displayed. As a result, the case where the above-mentioned liquid crystal display device maintained a black display was evaluated as ○, and the case where white was seen due to light leakage was evaluated as ´.

In addition, the ESD property of the conductive film after the glass substrate with the conductive film was kept at a temperature of 65 ° C. and a relative humidity of 90% for 500 hours was measured in the same manner as the ESD property after the high temperature and high humidity test. .

The above results are shown in Tables 6 and 7.

1‧‧‧ On-Cell type touch panel

2‧‧‧ lower polarizer

3‧‧‧ upper polarizer

4‧‧‧TFT substrate

5‧‧‧ common electrode

5’‧‧‧Common electrode and touch detection electrode

6‧‧‧ insulating film

72‧‧‧LCD layer

8‧‧‧ color filter substrate

9‧‧‧ touch panel substrate

9’‧‧‧Second touch panel substrate

10‧‧‧ conductive film

11‧‧‧ Adhesive layer

12‧‧‧ Adhesive layer

13‧‧‧ cover glass

FIG. 1 is a cross-sectional view showing a structure of an on-cell touch panel according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a layer structure of a cell-type touch panel to which the coating composition of the present invention can be applied. FIG. 3 is a cross-sectional view schematically showing a layer structure of an In-Cell type touch panel to which the coating composition of the present invention can be applied. Fig. 4 is a transmission electron microscope photograph of the chain-shaped antimony-containing tin oxide particles used in Example 1. FIG. 5 is an enlarged transmission electron microscope photograph of FIG. 4.

Claims (13)

A coating composition is a coating composition containing chain-shaped conductive inorganic particles, a binder, a high-boiling solvent and a low-boiling solvent. 涂布 The coating composition is relative to the chain-shaped conductive inorganic particles and the binder. In total, the content of the chain-shaped conductive inorganic particles is 10 to 70% by mass. It is used for: a TFT substrate, a liquid crystal layer, a color filter substrate, and a substrate having a laminated layer between two polarizing plates in order. In a touch panel of a control panel substrate, the use of a conductive film is formed on a surface on which an electrode pattern of the touch panel substrate exists. For example, the coating composition of claim 1 contains a solid component composed of the chain-shaped conductive inorganic particles and the binder in an amount of 0.1 to 5.0% by mass, and has a viscosity of 7.0 mPa · s or less. The coating composition according to claim 1 or 2, wherein the chain-shaped conductive inorganic particle-based primary particle having a particle diameter of 2 to 30 nm is connected to 2 to 50 particles. The coating composition according to any one of claims 1 to 3, wherein the chain-shaped conductive inorganic particles are selected from the group consisting of tin oxide particles containing antimony, indium oxide particles containing tin, and tin oxide particles containing phosphorus. Group of at least one particle. The coating composition according to any one of claims 1 to 4, wherein the aforementioned touch panel is a touch panel having a second touch panel substrate laminated between a TFT substrate and a color filter substrate. A conductive film is used on a touch panel substrate having a TFT substrate, a liquid crystal layer, a color filter substrate, and a touch panel substrate laminated in order between two polarizing plates. It is formed by coating the composition according to any one of claims 1 to 5. The conductive film according to claim 6, which has a film thickness of 2 to 100 nm. For example, the conductive film of claim 6 or 7 has a surface resistance of 1.0 × 10 ⁹ to 1.0 × 10 ¹⁴ W / □ or more. The conductive film according to any one of claims 6 to 8, which has a pencil hardness of 3H to 9H. The conductive film according to any one of claims 6 to 9, wherein the aforementioned touch panel is a touch panel having a second touch panel substrate laminated between a TFT substrate and a color filter substrate. A touch panel having a TFT substrate, a liquid crystal layer, a color filter substrate, a touch panel substrate, and the conductivity according to any one of claims 6 to 9 laminated in order between two polarizing plates. membrane. The touch panel as claimed in claim 11, which has a second touch panel substrate laminated between a TFT substrate and a color filter substrate. A method for forming a conductive film included in a touch panel having a TFT substrate, a liquid crystal layer, a color filter substrate, and a touch panel substrate laminated in order between two polarizing plates, A step of applying a coating composition on a surface where an electrode pattern of the touch panel substrate exists and drying the coating composition; the coating composition includes chain-shaped conductive inorganic particles, a binder, a high-boiling point solvent, and a low-boiling point solvent; The content of the chain-shaped conductive inorganic particles is 10 to 70% by mass relative to the total amount of the chain-shaped conductive inorganic particles and the binder, and the coating is performed by a spray method.