JP6048148B2 - Coating composition for touch panel, coating film and touch panel - Google Patents

Description

  The present invention relates to a coating composition for a touch panel, a coating film formed from the coating composition, and a touch panel having the coating film.

  Conventionally, inorganic coatings have been formed for various purposes on the surface of a substrate such as glass, ceramic, metal, and plastic. By forming an inorganic coating on the surface of the substrate, it is possible to impart electrical properties, optical properties, chemical properties, mechanical properties, and the like to the substrate. Therefore, these inorganic coatings have been put into practical use as conductive films, insulating films, selective transmission or absorption films of light rays, alkali elution prevention films, chemical resistant films, hard coat films, and the like.

  Examples of a method for forming such an inorganic coating include a vapor phase method such as CVD (Chemical Vapor Deposition), PVD (Physical Vapor Deposition), and sputtering, or a liquid phase method using an alkoxide compound.

  In general, the vapor phase method requires an expensive and large-scale apparatus such as a vacuum deposition apparatus. There is also a problem that the size and shape of the base material on which the film can be formed are limited. On the other hand, as a liquid phase method using an alkoxide compound or the like, a so-called sol-gel method is known. This method has advantages such as application to a large area and support for patterning. For this reason, the inorganic film by a liquid phase method is actively used as a coating film in an electronic device (for example, refer to Patent Document 1). In particular, recently, application to a touch panel has been studied.

  In recent years, with the spread of smartphones, the display screen of mobile phones has become larger. For this reason, development of the touch panel which can perform input operation using the display of a display is performed actively. According to the touch panel, an input unit such as a push-down switch is not necessary, and the display screen can be enlarged.

  The touch panel detects a contact position of an operation area touched by a finger or a pen. Using this function, the touch panel is used as an input device. The contact position detection method includes a resistance film method and a capacitance method. The resistive film method uses two opposing substrates, whereas the capacitive method allows a single substrate to be used. For this reason, according to the electrostatic capacity method, a thin touch panel can be configured and is suitable for a portable device or the like, so that development has been actively promoted in recent years.

  Patent Document 2 discloses a capacitive touch panel. In this touch panel, a first transparent electrode for detecting coordinates in the X direction and a second transparent electrode for detecting coordinates in the Y direction are arranged on one surface of the transparent substrate, and intersect each other. An interlayer insulating film is interposed in the portion so as not to conduct.

  The touch panel is incorporated in a display device such as a liquid crystal display device, and is used as a display device with a touch panel function capable of detecting a touch position. Since a person who operates the touch panel visually recognizes the display device through the touch panel, a member having excellent light transmission characteristics is used for the transparent electrode. For example, an inorganic material such as ITO (Indium Tin Oxide) is used. As the interlayer insulating film, patterning is possible, and an insulating acrylic material or the like is used.

Japanese Patent No. 2881847 Japanese Unexamined Patent Publication No. 2010-28115

  The touch panel as described above is required to have strength and high reliability because a finger or a pen tip may be actually touched and pressed in the operation area. Therefore, studies have been made to provide a protective film on the first and second electrodes that overlap with each other via an interlayer insulating film.

  As the protective film, a patternable acrylic material is used. However, since the acrylic material is an organic material, the hardness as a protective film is not sufficient. Moreover, when ITO etc. are used for a transparent electrode, the adhesiveness with respect to ITO is weak, and becomes a cause of reducing the reliability of a touch panel. Furthermore, it is difficult to form a film using an acrylic material using a printing technique such as flexographic printing. For this reason, it is necessary to use a photolithography technique with complicated processes in forming the film.

  For these reasons, a coating film containing an inorganic material as a component instead of an acrylic film has been studied as a protective film. In the case of a film containing an inorganic material as a component, the hardness is generally high, and high reliability can be expected as a coating film for a touch panel. For this reason, it is required that a coating film using an inorganic material as a component can be formed using a printing technique and has high adhesion to an interlayer insulating film made of an organic material such as an acrylic material. ing.

  Further, in a capacitive touch panel, a difference in reflectance occurs between a region where a transparent electrode such as ITO is formed and a region where a transparent electrode is not formed. As a result, there is a problem that the pattern of the transparent electrode is visually recognized and display properties are lowered.

  As described above, in the conventional touch panel, an acrylic film has been used as a protective film material on the transparent electrode. However, in this case, no consideration is given to the refractive index characteristics of the acrylic film. Therefore, the effect of making the transparent electrode pattern inconspicuous in the acrylic film cannot be expected. Therefore, when a coat film containing an inorganic material as a component is used instead of the acrylic film, the coat film preferably makes the transparent electrode pattern inconspicuous. Specifically, it is preferable to use a coating film in which the refractive index is considered.

  The present invention has been made in view of these points. That is, an object of the present invention is to provide a coating film with a controlled refractive index that can be applied to a touch panel to achieve high reliability, and a coating composition that can form such a coating film.

  Another object of the present invention is to provide a touch panel having a coating film on an electrode, the refractive index of which is controlled and high reliability can be realized.

The present invention is for achieving the above-mentioned object, and the gist thereof is as follows.
1. A coating composition for forming a coating film on at least a part of a transparent electrode in a touch panel having a transparent electrode pattern in an operation region of a substrate, the first metal alkoxide represented by the following general formula (I) And a second metal alkoxide represented by the following general formula (II), a metal salt represented by the following general formula (III), an organic solvent, water, and a precipitation inhibitor , the content of the second metal alkoxide, based on the total metal alkoxide combined first metal alkoxide and a second metal alkoxide, a touch panel for a coating composition, characterized in 15 to 80 mole% der Rukoto.
M ¹ (OR ¹ ) _n (I)
(Wherein M ¹ is a group consisting of silicon (Si), titanium (Ti), tantalum (Ta), zirconium (Zr), boron (B), aluminum (Al), magnesium (Mg) and zinc (Zn). R ¹ represents an alkyl group having 1 to 5 carbon atoms, and n represents a valence 2 to 5 of M ¹ .
R ² _l M ² (OR ³ ) _ml (II)
(Wherein M ¹ is a group consisting of silicon (Si), titanium (Ti), tantalum (Ta), zirconium (Zr), boron (B), aluminum (Al), magnesium (Mg) and zinc (Zn). It represents at least one metal selected from .R ² is main mercapto group, methacryloxy group, acryloxy group, were or are substituted with a ureido group, and, optionally carbon atoms 1 to have a hetero atom Represents a hydrocarbon group of 20. R ³ represents an alkyl group having 1 to 5 carbon atoms, m represents a valence of 2 to 5 of M ² , and l represents 1 when m has a valence of 3 or 2 is 1 to 3 when the valence of m is 4, and 1 to 4 when the valence of m is 5.)
M ³ (X) _k (III)
(Wherein M ³ represents aluminum (Al), indium (In), zinc (Zn), zirconium (Zr), bismuth (Bi), lanthanum (La), tantalum (Ta), yttrium (Y) and cerium ( Ce) represents at least one metal selected from the group consisting of: X is a residue of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, succinic acid, sfamic acid, sulfonic acid, acetoacetic acid or acetylacetonate, or their basicity Represents a salt, and k represents the valence of M ^3. )

2 . 2. The touch panel as described in 1 above, wherein the precipitation inhibitor is at least one selected from the group consisting of N-methyl-pyrrolidone, ethylene glycol, dimethylformamide, dimethylacetamide, diethylene glycol, propylene glycol, hexylene glycol and derivatives thereof. Coating composition.

3. The molar ratio of the metal atom (M ³ ) of the metal salt to the metal atoms (M ¹ and M ² ) of the first metal alkoxide and the second metal alkoxide is:
0.01 ≦ M ³ / (M ¹ + M ² + M ³ ) ≦ 0.7
The coating composition for touch panels as described in 1 or 2 above.
4). 4. The touch panel coating composition according to any one of 1 to 3 , wherein the first metal alkoxide is a mixture of silicon alkoxide or a partial condensate thereof and titanium alkoxide.
5. The metal salt is a metal nitrate, metal sulfate, metal acetate, metal chloride, metal oxalate, metal sphamate, metal sulfonate, metal acetoacetate, metal acetylacetonate or a basic salt thereof. The coating composition for touchscreens in any one of Claims 1-4 .
6). The said organic solvent is a coating composition in any one of said 1-5 containing alkylene glycol or its monoether derivative.
7). The coating film formed into a film using the coating composition for touchscreens in any one of said 1-6 .
8). 8. The coating film according to 7 above, having a refractive index of 1.52 to 1.70 and a film thickness of 40 nm to 170 nm.
9. A touch panel in which a transparent electrode pattern is formed in an operation region of a substrate, wherein the coating film according to 7 or 8 is disposed on at least a part of the transparent electrode pattern.
10. The transparent electrode pattern includes a first transparent electrode pattern for detecting positions in at least two different directions, and a second transparent electrode pattern,
At least a part of the first transparent electrode pattern and the second transparent electrode pattern overlap each other in the operation region of the substrate, and the first transparent electrode pattern and the second transparent electrode in the overlapping part A film made of organic material is placed between the pattern and
The touch panel according to claim 9 , wherein the coating film is configured to cover at least a part of the film made of the organic material together with at least a part of the first transparent electrode pattern or the second transparent electrode pattern.
11. There are a plurality of overlapping portions of the first transparent electrode pattern and the second transparent electrode pattern in the operation region of the substrate, and each of the overlapping portions has an area larger than the area of the overlapping portion. 11. The touch panel as described in 10 above, wherein a film made of the organic material is arranged.

  ADVANTAGE OF THE INVENTION According to this invention, the coating composition for touchscreens which can be applied to a touchscreen and can form the coating film with which the refractive index was controlled which can implement | achieve high reliability is provided.

  Moreover, according to this invention, a refractive index is controlled and it has high intensity | strength and the coating film suitable as a coating film of a touchscreen is provided.

  ADVANTAGE OF THE INVENTION According to this invention, it is suppressed that the pattern of an electrode is conspicuous and the touch panel which has high reliability is provided.

It is a top view which shows typically the structure of the touchscreen of this invention. It is sectional drawing which follows the A1-A1 'line | wire of FIG. (A)-(d) is process sectional drawing which shows the manufacturing method of the touchscreen of this invention. It is sectional drawing which shows schematic structure of another example of the touchscreen of this invention. It is a top view which shows typically the structure of another example of the touchscreen of this invention. It is sectional drawing which follows the B1-B1 'line | wire of FIG.

<Coating composition>
The coating composition of the present invention includes a first metal alkoxide represented by the above general formula (I), a second metal alkoxide represented by the above general formula (II), and a metal represented by the above general formula (III). Contains a salt, an organic solvent, moisture, and a precipitation inhibitor. A coating suitable for a touch panel can be obtained by depositing this coating composition.

  The coating film obtained from the coating composition of the present invention is mainly composed of an inorganic metal oxide, and has a higher hardness and higher strength than a coating film made of an organic material such as an acrylic material. Have. Therefore, it is suitable as a protective film for an electrode of a touch panel. Further, the refractive index is controlled within the optimum range so as to reduce the so-called “electrode pattern appearance” phenomenon in which the transparent electrode pattern is visually recognized on the touch panel. As a result, it is possible to prevent deterioration in display properties of a display device to which a touch panel using this coat film is applied.

  The coating film obtained by the present invention is configured, for example, by including two types of transparent electrode patterns for detecting the positions in two different directions in the transparent electrode pattern arranged in the operation region of the touch panel substrate. Sometimes. At this time, an interlayer insulating film made of an organic material such as acrylic is disposed between the two transparent electrode patterns so as not to be electrically connected. In the case of the touch panel having such a configuration, the coat film is also formed on the interlayer insulating film. Here, due to the difference in thermal stretchability between the coat film and the interlayer insulating film, there is a problem that the coat film cracks and the reliability of the touch panel is lowered.

  In the coating composition of this invention, it selects suitably about the structure and composition of the component to contain so that a crack may not generate | occur | produce in the coating film of a touch panel. More specifically, in the coating composition of the present invention, the metal alkoxide that is the main component can be selected in a structure and composition that are suitable for forming a coating film.

式（Ｉ）中、Ｍ^１、Ｒ^１、ｎは、上記に定義したとおりである。なかでも、Ｍ^１は、珪素（Ｓｉ）、チタン（Ｔｉ）、ジルコニウム（Ｚｒ）、またはアルミニウム（Ａｌ）が好ましく、特には、珪素（Ｓｉ）、またはチタン（Ｔｉ）が好ましい。また、ｎは３または４が好ましい。

式（ＩＩ）中、Ｍ^２、Ｒ^２、Ｒ^３、ｍは、上記に定義したとおりである。なかでも、Ｍ^２は、珪素（Ｓｉ）、チタン（Ｔｉ）、ジルコニウム（Ｚｒ）、またはアルミニウム（Ａｌ）が好ましく、特には、珪素（Ｓｉ）、またはチタン（Ｔｉ）が好ましい。The coating composition of the present invention contains a first metal alkoxide having a structure represented by the following general formula (I) and a second metal alkoxide having a structure represented by the following general formula (II).

In formula (I), M ¹ , R ¹ and n are as defined above. Among these, M ¹ is preferably silicon (Si), titanium (Ti), zirconium (Zr), or aluminum (Al), and particularly preferably silicon (Si) or titanium (Ti). N is preferably 3 or 4.

In formula (II), M ² , R ² , R ³ and m are as defined above. Among these, M ² is preferably silicon (Si), titanium (Ti), zirconium (Zr), or aluminum (Al), and particularly preferably silicon (Si) or titanium (Ti).

式（ＩＶ）中、Ｒ’は、炭素数１〜５、好ましくは、１〜３のアルキル基、またはアセトキシ基を表す。When a silicon alkoxide or a partial condensate thereof is used as the metal alkoxide represented by the formula (I), one or a mixture or a partial condensate (preferably a pentamer) of the compound represented by the general formula (IV) The following is used:

In the formula (IV), R ′ represents an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, or an acetoxy group.

  More specifically, as the silicon alkoxide, for example, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and tetraacetoxysilane are used.

式（Ｖ）中、Ｒ”は、炭素数１〜５のアルキル基を表す。
式（Ｉ）で示される金属アルコキシドとして、具体的には、チタンアルコキシドとして、チタニウムテトラエトキシド、チタニウムテトラプロポキシド、チタニウムテトラブトキシドなどのチタニウムテトラアルコキシド化合物またはチタニウムテトラ−ｎ−ブトキシドテトラマーなどの部分縮合物などが用いられる。When a titanium alkoxide or a partial condensate is used as the metal alkoxide represented by the formula (I), one or a mixture of two or more compounds or a partial condensate of the compound represented by the general formula (V) (preferably 5 amounts) Body or less) is used.

In formula (V), R ″ represents an alkyl group having 1 to 5 carbon atoms.
As the metal alkoxide represented by the formula (I), specifically, as titanium alkoxide, a titanium tetraalkoxide compound such as titanium tetraethoxide, titanium tetrapropoxide, titanium tetrabutoxide or a portion such as titanium tetra-n-butoxide tetramer A condensate or the like is used.

  Other examples of the metal alkoxide represented by the formula (I) include zirconium tetraalkoxide compounds such as zirconium tetraethoxide, zirconium tetrapropoxide, zirconium tetrabutoxide; aluminum tributoxide, aluminum triisopropoxide, aluminum triethoxide And aluminum trialkoxide compounds such as tantalum pentapropoxide and tantalum pentaalkoxide compounds such as tantalum pentataboxide.

  The content of the first metal alkoxide is preferably 20 mol% to 85 mol%, preferably 30 mol% to 70 mol%, based on the total amount of one metal alkoxide and second metal alkoxide contained in the coating composition. Mole% is more preferable.

  The second metal alkoxide represented by the above formula (II) is used in the coating composition of the present invention together with the first metal alkoxide. In the coating composition, when the coating film is formed on a film made of an organic material such as an acrylic material by including the second metal alkoxide, there is a difference in thermal stretchability between the coating film and the organic film. Alleviated. As a result, even if a coat film may be formed on the organic film, it is possible to prevent cracks from occurring in the coat film. For example, in a touch panel, even when an organic film made of an acrylic material is used for the above-described interlayer insulating film and a coat film is formed on the organic film, a crack occurs in the coat film on the interlayer insulating film. Can be prevented.

The content of the second metal alkoxide content is preferably 80 mol% to 15 mol%, preferably 70% to 30 mol, based on the total amount of one metal alkoxide and the second metal alkoxide contained in the coating composition. % Is more preferable. When the carbon number of R ² is 3 or less, the content of the metal alkoxide represented by the formula (II) is 30% or more, and when the carbon number of R ² is 4 or more, or a mercapto group is contained in R ² In this case, the content of the second metal alkoxide is more preferably 15% or more, and more preferably 75 mol% or less.
When the content of the second metal alkoxide is less than 15 mol%, a crack may occur in the coating film obtained on the above-described organic film. On the other hand, if it is 80 mol% or more, cracks may not occur, but a phenomenon that a uniform coating film cannot be obtained may occur. By setting it as such content, crack generation | occurrence | production in an above-described coat film can be suppressed.

  The total content of the first metal alkoxide and the second metal alkoxide contained in the coating composition is preferably 0.5 wt% to 20 wt%, more preferably 1 wt% to 15 wt%. When this ratio is large, the storage stability of the coating composition is deteriorated and it is difficult to control the film thickness of the coating film. On the other hand, when the thickness is small, the thickness of the resulting coating film becomes thin, and many coatings are required to obtain a predetermined film thickness.

As a preferable metal alkoxide represented by the formula (II), for example, when M ² is silicon, the following compounds may be mentioned.
For example, gamma - methacryloxypropyltrimethoxysilane, .gamma.-mercaptopropyltrimethoxysilane, .gamma.-mercaptopropyl triethoxysilane emissions, gamma - methacryloxypropyl methyl dimethoxy silane, .gamma.-methacryloxypropyl methyl diethoxy silane, .gamma. mercaptopropylmethyldimethoxysilane, .gamma.-mercapto methyl diethoxy Sila down, 3 - methacryloxypropyl trimethoxy silane, 3-methacryloxypropyl triethoxysilane, 3-acryloxy propyl trimethoxy silane, 3-acryloxy propyl triethoxysilane etc. emissions can be mentioned. These can be used alone or in combination of two or more.

式（ＩＩＩ）中、Ｍ^３、Ｘ、ｋは、上記に定義したとおりである。なかでも、Ｍ^３は、アルミニウム（Ａｌ）、インジウム（Ｉｎ）、セリウム（Ｃｅ）またはジルコニウム（Ｚｒ）が好ましい。また、Ｘは、塩酸、硝酸、酢酸、蓚酸、スルホン酸、アセト酢酸若しくはアセチルアセトナートの残基、またはそれらの塩基性塩が好ましい。上記Ｘにおける各酸の残基は、例えば、硝酸は硝酸根、硫酸は硫酸根とも呼ばれ、その量は、Ｍ^３の価数と等価になるように含まれる。また、塩基性塩とは、上記各酸の残基中にＯＨ基を含む場合を意味する。
式（ＩＩＩ)で示される金属塩のうち、特に、硝酸塩、塩化物塩、蓚酸塩またはその塩基性塩が好ましい。この内、入手の容易性と、コーティング組成物の貯蔵安定性の点から、アルミニウム、インジウム、またはセリウムの硝酸塩がより好ましい。The metal salt contained in the coating composition of the present invention is represented by the following general formula (III).

In formula (III), M ³ , X and k are as defined above. Among these, M ³ is preferably aluminum (Al), indium (In), cerium (Ce), or zirconium (Zr). X is preferably a residue of hydrochloric acid, nitric acid, acetic acid, succinic acid, sulfonic acid, acetoacetic acid or acetylacetonate, or a basic salt thereof. The residue of each acid in X is, for example, nitric acid is also called a nitrate radical and sulfuric acid is also called a sulfate radical, and the amount thereof is included so as to be equivalent to the valence of M ³ . Moreover, a basic salt means the case where OH group is contained in the residue of said each acid.
Of the metal salts represented by the formula (III), nitrates, chloride salts, oxalates or basic salts thereof are particularly preferable. Of these, aluminum, indium, or cerium nitrate is more preferred from the viewpoint of availability and storage stability of the coating composition.

  The coating composition of the present invention contains an organic solvent. The organic solvent is for adjusting the viscosity of the coating composition and improving the coating property when forming a coating film from the coating composition to obtain a coating film. Content of the organic solvent in the coating composition Is preferably 80 wt% to 99.5 wt%, more preferably 85 wt% to 99 wt%, based on the total metal alkoxide contained in the coating composition. When the content of the organic solvent is small, the thickness of the resulting coating film is reduced, and many coatings are required to obtain a predetermined film thickness. On the other hand, when the amount is large, the storage stability of the coating composition is deteriorated and it is difficult to control the thickness of the coating film.

  Examples of the organic solvent used in the coating composition include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, and 2-methyl-2-propanol. Esters such as ethyl acetate; glycols such as ethylene glycol; or ester derivatives thereof; ethers such as diethyl ether; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; aromatic hydrocarbons such as benzene and toluene; Is mentioned. These are used alone or in combination.

  When the coating composition contains a titanium alkoxide component, the alkylene glycol or monoether thereof contained in the organic solvent is, for example, ethylene glycol, diethylene glycol, propylene glycol, hexylene glycol, or their monomethyl, monoethyl , Monopropyl, monobutyl or monophenyl ether.

  When the molar ratio of the glycols or monoethers contained in the organic solvent used in the coating composition is less than 1 with respect to the titanium alkoxide, the stability of the titanium alkoxide is small, and the storage stability of the coating composition is reduced. Sexuality gets worse. on the other hand. It is not a problem to use a large amount of glycols or monoethers thereof. For example, all of the organic solvents used in the coating composition can be the above-described glycols or monoethers thereof. However, when the coating composition does not contain a titanium alkoxide, it is not necessary to specifically contain the above-mentioned glycol and / or its monoether.

  The coating composition preferably contains a precipitation inhibitor. The anti-deposition agent prevents the metal salt from precipitating in the coating film when a coating film is formed from the coating composition. Examples of the precipitation inhibitor include N-methyl-pyrrolidone, dimethylformamide, dimethylacetamide, ethylene glycol, diethylene glycol, propylene glycol, hexylene glycol, and derivatives thereof. Of these, N-methyl-pyrrolidone, ethylene glycol, diethylene glycol, propylene glycol, hexylene glycol or derivatives thereof are more preferable. At least one kind of precipitation inhibitor can be used.

The content of the precipitation inhibitor in the coating composition is preferably used at a ratio (weight ratio) satisfying the following, when the metal of the metal salt is converted into a metal oxide.
(Precipitation inhibitor / metal oxide) ≧ 1
When the ratio is less than 1, the effect of preventing precipitation of the metal salt at the time of forming the coating film is reduced. On the other hand, the use of a large amount of precipitation inhibitor does not affect the coating composition at all, but is preferably 200 or less.

  In the precipitation inhibitor, metal alkoxide, particularly silicon alkoxide, titanium alkoxide, or silicon alkoxide and titanium alkoxide may be added during hydrolysis / condensation reaction in the presence of a metal salt. It may be added after completion of the condensation reaction.

On the other hand, the content of the metal salt contained in the coating composition is the sum of the metal atoms (M ¹ and M ² ) constituting the first and second metal alkoxides and the metal atom (M ³ ) of the metal salt. The content ratio is preferably a ratio (molar ratio) that satisfies the following.
0.01 ≦ M ³ / (M ¹ + M ² + M ³ ) ≦ 0.7
If this ratio is less than 0.01, the mechanical strength of the resulting coating is not sufficient, which is not preferable. On the other hand, when it exceeds 0.7, the adhesion of the coating film to a substrate such as a glass substrate or a transparent electrode is lowered. Furthermore, when baked at a low temperature of 450 ° C. or lower, the chemical resistance of the resulting coating film tends to be lowered. Especially, it is more preferable that this ratio is 0.01 to 0.6.

In the coating composition of the present invention, other components than the above-described components, for example, inorganic fine particles, metalloxane oligomers, metalloxane polymers, leveling agents, surfactants and the like, as long as the effects of the present invention are not impaired. May be included.
As the inorganic fine particles, fine particles such as silica fine particles, alumina fine particles, titania fine particles, and magnesium fluoride fine particles are preferable, and a colloid solution of these inorganic fine particles is particularly preferable. This colloidal solution may be a dispersion of inorganic fine particle powder in a dispersion medium or a commercially available colloidal solution.

In the present invention, the inclusion of inorganic fine particles makes it possible to impart the surface shape of the formed cured film and other functions. The inorganic fine particles preferably have an average particle size of 0.001 to 0.2 μm, more preferably 0.001 to 0.1 μm. When the average particle diameter of the inorganic fine particles exceeds 0.2 μm, the transparency of the cured film formed using the prepared coating liquid may be lowered.
Examples of the dispersion medium for the inorganic fine particles include water and organic solvents. As a colloidal solution, it is preferable that pH or pKa is adjusted to 1-10, More preferably, it is 2-7 from a stability viewpoint of the coating liquid for film formation.

  Organic solvents used for the dispersion medium of the colloidal solution include methanol, ethanol, propanol, butanol, ethylene glycol, propylene glycol, butanediol, pentanediol, 2-methyl-2,4-pentanediol, diethylene glycol, dipropylene glycol, ethylene Alcohols such as glycol monopropyl ether; ketones such as methyl ethyl ketone and methyl isobutyl ketone; aromatic hydrocarbons such as toluene and xylene; amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone; ethyl acetate and butyl acetate And esters such as γ-butyrolactone; ethers such as tetrahydrofuran and 1,4-dioxane. Of these, alcohols and ketones are preferred. These organic solvents can be used alone or in admixture of two or more as a dispersion medium.

  The solid content concentration in the coating composition of the present invention is preferably in the range of 0.5 wt% to 20 wt% when the metal alkoxide and metal salt are converted as metal oxides. When the solid content exceeds 20% by weight, the storage stability of the coating composition is deteriorated and it is difficult to control the thickness of the coating film. On the other hand, when the solid content is less than 0.5% by weight, the resulting coating film is thin, and many coatings are required to obtain a predetermined film thickness. Especially, it is more preferable that solid content concentration is 1 to 15 weight%.

  The coating composition of the present invention contains water in order to hydrolyze the first and second metal alkoxides in the presence of the metal salt to obtain a condensate. The amount of water is preferably 2 to 24 moles relative to the total moles of the first and second metal alkoxides. When the ratio of (amount of water (mole) / (total number of moles of metal alkoxide) is 2 or less, hydrolysis of the metal alkoxide becomes insufficient, resulting in a decrease in film formability or a coat obtained. It is not preferable because the strength of the film is decreased, and when the ratio is more than 24, polycondensation continues to proceed, so that storage stability is decreased. More preferably, it is ~ 20.

  In addition, when the metal salt contained in the coating composition is a hydrate salt, the moisture content is involved in the hydrolysis reaction, so the amount of water contained in the coating composition includes the moisture content of the metal salt. It is necessary to consider. For example, when the coexisting metal salt is a hydrated salt of an aluminum salt, it is necessary to consider the moisture content of the aluminum salt with respect to the amount of water used for hydrolysis because the moisture content is involved in the reaction.

  The coating composition of the present invention can form a coating film suitable for a touch panel. This coat film is a coat film containing an inorganic metal oxide as a main component, and has higher strength than a film made of an organic material such as an acrylic material. And in the touch panel mentioned later, it applies as a protective film of an electrode. Since the coat film has an appropriate thermal expansion / contraction characteristic, even if it is formed on the organic film constituting the touch panel, generation of cracks is suppressed to a minimum. In addition, the refractive index is controlled in an optimal range so that a decrease in display performance of the display device due to the visual recognition of the transparent electrode pattern is reduced.

  Control of the refractive index of the coating film can be realized by controlling the composition of the coating composition. That is, the coating film in the present invention is produced by hydrolyzing and condensing the metal alkoxide contained in the coating composition described above. By selecting the composition of the metal alkoxide, the coating film to be formed is refracted. It is possible to adjust the rate within a predetermined range. For example, when silicon alkoxide and titanium alkoxide are selected as the metal alkoxide, by adjusting the mixing ratio thereof, within a predetermined range described below, specifically within a range of about 1.45 to 2.1, It is possible to adjust the refractive index of the resulting coating film.

  That is, when a required refractive index is determined in a coating film formed by applying a coating composition and forming a film, preferably after drying and baking, a metal is formed so as to realize the refractive index. It is possible to determine the composition molar ratio of alkoxide, for example, silicon alkoxide and titanium alkoxide. For example, the refractive index of a coating film from a coating composition obtained by hydrolyzing only silicon alkoxide is a value of about 1.45. And the refractive index of the coating film from the coating composition obtained by hydrolyzing only a titanium alkoxide is a value of about 2.1. Therefore, when it is desired to set the refractive index of the coating film to a specific value between about 1.45 and 2.1, coating is performed using silicon alkoxide and titanium alkoxide at a predetermined ratio so as to realize the refractive index value. It is possible to produce a composition.

  The refractive index of the resulting coating film can also be adjusted by using other metal alkoxides. Furthermore, the refractive index of the coating film in the present invention can be adjusted by selecting film forming conditions in addition to the composition conditions. In this way, it is possible to realize a high hardness of the coating film and a desired refractive index value.

When obtaining a coated film from the coating composition of the present invention, the coating film of the coating composition is preferably dried and then baked as described above. Drying is preferably performed at room temperature to 150 ° C, and more preferably at 40 to 120 ° C. The drying time is preferably about 30 seconds to 10 minutes, and more preferably about 1 to 8 minutes. As a drying method, it is preferable to use a hot plate, a hot air circulating oven, or the like.
The firing is preferably performed at 100 ° C. to 300 ° C., more preferably 150 ° C. to 250 ° C. in consideration of the heat resistance of the other components of the touch panel. The firing time is preferably 5 minutes or more, and more preferably 15 minutes or more. As a baking method, it is preferable to use a hot plate, a thermal circulation oven, an infrared oven, or the like.
When a coating film is produced by baking a coating film of the coating composition, the refractive index of the coating film obtained varies depending on the baking temperature. In this case, the higher the baking temperature, the higher the refractive index of the coating film. Therefore, the refractive index of the resulting coating film can be adjusted by selecting an appropriate baking temperature.

  Moreover, when obtaining a coat film from a coating composition, if the coating film is irradiated with ultraviolet rays (UV) before firing, the refractive index of the resulting coat film varies. Specifically, the refractive index of the coat film can be increased as the amount of ultraviolet irradiation is increased. Therefore, it is possible to select the presence or absence of ultraviolet irradiation in order to achieve a desired refractive index. In particular, when the metal alkoxide contained in the coating composition contains titanium alkoxide, zirconium alkoxide, or tantalum alkoxide, the refractive index of the resulting coating film fluctuates due to ultraviolet (UV) irradiation to the coating before firing, and ultraviolet rays The higher the irradiation amount, the higher the refractive index of the coat film. In the coating film, when a desired refractive index can be realized by selecting conditions such as composition, ultraviolet irradiation is not necessary.

When ultraviolet irradiation is performed, the refractive index of the coating film can be adjusted by selecting the irradiation amount. When the coating film needs to be irradiated with ultraviolet rays in order to obtain a desired refractive index, for example, a high-pressure mercury lamp can be used. In 365nm terms when using a high-pressure mercury lamp, total light irradiation 1000 mJ / cm ² or more dose are preferred ^and the dose of 3000mJ / cm ² ~10000mJ / cm 2 is more preferable. As an ultraviolet light source, in addition to a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, a xenon lamp, an excimer lamp, or the like can be used. In the case of using a light source other than the case of using a high-pressure mercury lamp, it is only necessary to irradiate the same amount of integrated light as in the case of using the high-pressure mercury lamp. When performing ultraviolet irradiation, an ultraviolet irradiation process can also be performed between a drying process and a baking process.

  In particular, when the coating composition contains a titanium alkoxide component, the coating composition has the property of gradually increasing the viscosity under storage at room temperature. Although there is no concern that this will cause a serious problem in practice, careful control over temperature and the like is preferable when the thickness of the coating film is precisely controlled. Such an increase in viscosity becomes more significant as the composition ratio of titanium alkoxide in the coating composition increases. This is presumably because titanium alkoxide has a higher hydrolysis rate than silicon alkoxide and the like, and the condensation reaction is fast.

In the case where the coating composition contains a titanium alkoxide component, the following two production methods (1) and (2) are preferable in order to reduce the viscosity change.
(1) When hydrolyzing titanium alkoxide in the presence of a metal salt, after sufficiently mixing glycols and titanium alkoxide in advance, if necessary, it is mixed with silicon alkoxide and hydrolyzed in the presence of an organic solvent. . By doing so, a coating composition having a small viscosity change can be obtained. The production method of (1) is effective because when titanium alkoxide is mixed with glycols, heat is generated, so transesterification occurs between the alkoxy group of titanium alkoxide and glycols, resulting in hydrolysis / condensation reaction. This is thought to be because of stabilization.

(2) A silicon alkoxide is preliminarily hydrolyzed in the presence of a metal salt and then mixed with a titanium alkoxide solution mixed with glycols to perform a condensation reaction to obtain a coating composition. By doing so, a coating composition having a small viscosity change can be obtained.
The reason why the production method (2) is effective is considered to be as follows. That is, the hydrolysis reaction of silicon alkoxide is performed at a high rate, but the subsequent condensation reaction is slower than titanium alkoxide. Therefore, when titanium alkoxide is added quickly after finishing the hydrolysis reaction, the silanol group of the hydrolyzed silicon alkoxide and the titanium alkoxide react uniformly. Thereby, it is thought that the hydrolyzed silicon alkoxide stabilizes the condensation reactivity of titanium alkoxide.

  Attempts have already been made to mix pre-hydrolyzed silicon alkoxide and titanium alkoxide. However, when the organic solvent used for the reaction does not contain glycols, a coating composition having excellent storage stability cannot be obtained. The method shown in 2) is also useful when a coating composition is obtained from another metal alkoxide having a high hydrolysis rate and silicon alkoxide.

  The coating composition of the present invention is formed by applying a commonly applied coating method to form a coating film and then forming a coating film. As the coating method, for example, a dip coating method, a spin coating method, a spray coating method, a brush coating method, a roll transfer method, a screen printing method, an ink jet method, or a flexographic printing method is used. Of these, the inkjet method and flexographic printing method suitable for pattern printing are particularly preferred.

<Coating film>
The coating film of the present invention is formed using the above-described coating composition of the present invention. And it applies to the touch panel of this invention mentioned later as an electrode protective film of a touch panel.
The coat film of the present invention is a coat film containing a metal oxide that is an inorganic substance as a component, and has higher hardness and higher strength than a coat film made of an organic material such as an acrylic material. That is, it excels in mechanical strength and protects the transparent electrode from multiple pressings with a finger or the like.

  When the touch panel is formed using a film made of an organic material, for example, when the interlayer insulating film disposed between the electrodes of the touch panel is formed of an organic material such as acrylic, the coating film of the present invention is particularly effective. It is. That is, even if the coating film of the present invention is formed on a film made of an organic material, the component composition is selected so that cracks do not occur due to the difference in thermal stretchability with the organic film.

  Further, the coating film of the present invention is also suitable as a protective film for an electrode of a touch panel described later. That is, according to this coat film, it is possible to suppress a phenomenon in which the transparent electrode pattern is visually recognized (electrode pattern appearance phenomenon). Therefore, according to the touch panel formed using this coat film, it is possible to reduce the deterioration in display properties of the display device.

  The reason why the transparent electrode pattern is visually recognized on the touch panel is that the refractive index of the transparent electrode pattern in the operation region of the substrate is different from the refractive index of the substrate. The transparent electrode pattern of the touch panel is usually made of ITO (Indium Tin Oxide) which is an inorganic metal oxide. The refractive index of ITO is about 1.8 to 2.1. Is approximately 1.4 to 1.5, and thus is significantly different from the refractive index of ITO, which is different between the region where the transparent electrode pattern is formed and the region where the transparent electrode pattern is not formed. In other words, the difference in the light reflection characteristic is caused between the area where the transparent electrode pattern is formed and the area where the transparent electrode pattern is not formed, thereby making the electrode pattern stand out in the screen display. .

  Therefore, as a result of intensive studies to make the transparent electrode pattern inconspicuous, the inventor has such that the refractive index and the film thickness are within a desired range on the transparent electrode pattern arranged on the substrate. It has been found that providing a controlled layer is effective. Specifically, it was found that by controlling the refractive index and the film thickness of the protective layer of the transparent electrode pattern within the optimum range, it is possible to suppress the unintended viewing of the transparent electrode pattern on the touch panel.

In the coating film of the present invention, particularly when the phenomenon of the transparent electrode pattern being visually recognized is to be suppressed, the refractive index is in the range of 1.50 to 1.70, preferably in the range of 1.52 to 1.70. It is controlled to become. As described above, the refractive index control method can be realized by controlling the component composition of the coating composition and also by controlling the film forming method.
As a method for forming the coating film, a coating method is applied to the coating composition of the present invention by applying a commonly applied coating method such as flexographic printing to form a coating film on the electrode of the touch panel, and then forming the coating film. Is mentioned.

<Touch panel>
Next, a touch panel having the coating film of the present invention will be described.
1 and 2 are diagrams for explaining the configuration of the touch panel of the present invention. FIG. 1 is a plan view schematically showing the structure of the touch panel. FIG. 2 is a cross-sectional view taken along line A1-A1 ′ of FIG.

  As shown in FIG. 1, the touch panel 1 is configured using a transparent substrate 2, and a transparent electrode pattern is formed in an operation region of the substrate 2. Specifically, in the operation region of the substrate 2, the first transparent electrode 3 extending in the Y direction and the second transparent electrode 4 extending in the X direction are included. The first transparent electrode 3 and the second transparent electrode 4 are formed from the same layer provided on the same surface of the substrate 2.

  The substrate 2 is made of a transparent material such as glass, acrylic resin, polyester resin, polyethylene terephthalate resin, polycarbonate resin, polyvinylidene chloride resin, polymethyl methacrylate resin, polyethylene naphthalate resin, or triacetyl cellulose resin. In particular, it is preferable to select a material having heat resistance and chemical resistance suitable for forming the coat film 5. The thickness of the substrate 2 is, for example, about 0.1 mm to 2 mm when glass is used, and is about 10 μm to 2000 μm, for example, when a resin film is used.

  In FIG. 1, each of the first transparent electrode 3 and the second transparent electrode 4 includes a plurality of pad portions 21 as components. The pad portions 21 are arranged so as to be separated from each other in a planar manner, and the gap between the pad portions 21 is reduced. That is, the pad portions 21 forming a row in the X-axis direction and the pad portions 21 forming a row in the Y-axis direction are arranged in the entire operation region so that the region where they intersect each other is as small as possible. The The pad part 21 can be made into polygonal shapes, such as a rhombus, a rectangle, and a hexagon, for example, These are arrange | positioned alternately or in series, for example. Further, the number of separated (separated) electrodes is not limited to the example in FIG. 1, and is determined according to the size of the operation area and the required detection position accuracy.

  The first transparent electrode 3 and the second transparent electrode 4 configured by connecting a plurality of pad portions 21 are formed at positions corresponding to the operation area of the touch panel 1. The first transparent electrode 3 is provided separately in a plurality of regions along the X direction, and detects coordinates in the X direction. The second transparent electrode 4 is provided separately in a plurality of regions along the Y direction, and detects coordinates in the Y direction. With such a structure, the accuracy of touch position detection can be increased.

  The first transparent electrode 3 and the second transparent electrode 4 are formed using a transparent electrode material having high transmittance at least for visible light and having conductivity. Examples of such a transparent electrode material having conductivity include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), and ZnO (zinc oxide). When ITO is used, the thickness is preferably 10 nm to 200 nm so as to ensure sufficient conductivity.

For example, the first transparent electrode 3 and the second transparent electrode 4 are formed as follows.
First, a transparent conductive film is formed by a method selected from sputtering, vacuum deposition, ion plating, spraying, dipping, CVD, or the like in consideration of the material of the substrate 2 as a base. Next, the transparent conductive film is patterned using a photolithography technique. Alternatively, a desired pattern may be formed by a printing method using a paint in which a conductive filler made of the above material is dispersed in an organic solvent.

  In the transparent electrode forming step, it is preferable that the film thickness can be accurately controlled. Therefore, it is preferable to select a method capable of forming a desired film thickness and forming a low-resistance film excellent in transparency.

  As shown in FIGS. 1 and 2, the first transparent electrode 3 and the second transparent electrode 4 are formed on the same surface of the substrate 2 and form the same layer. For this reason, the 1st transparent electrode 3 and the 2nd transparent electrode 4 cross | intersect in several places, and form the cross | intersection part 18. FIG.

  In the present invention, at the intersection 18, one of the first transparent electrode 3 and the second transparent electrode 4 is divided so as not to contact the other. That is, as shown in FIG. 2, the second transparent electrode 4 is connected at any of the plurality of intersecting portions 18, but the first transparent electrode 3 is divided. And in order to connect the parting part of the 1st transparent electrode 3, the bridge | crosslinking electrode 20 is provided. An interlayer insulating film 19 made of an insulating material is provided between the bridging electrode 20 and the second transparent electrode 4. Hereinafter, further details will be described with reference to FIGS. 1 and 2.

As shown in FIG. 2, a light transmissive interlayer insulating film 19 is formed on the second transparent electrode 4 at the intersection 18. An organic material such as a photosensitive acrylic resin is used to form the interlayer insulating film 19. When using a photosensitive acrylic resin, it is set as the structure where the acrylic film was formed only on the 2nd transparent electrode 4 in the cross | intersection part 18 using the photolithographic method. An inorganic material such as SiO ₂ can also be used. When SiO ₂ is used, a similar structure can be formed by, for example, a sputtering method using a mask. In consideration of patterning properties, it is preferable to use an acrylic film for the interlayer insulating film 19.

  A bridging electrode 20 is provided on the interlayer insulating film 19. The bridging electrode 20 is for electrically connecting the first transparent electrodes 3 separated by the intersecting portion 18, and is preferably formed of a light transmissive material. By providing the bridging electrode 20, the first transparent electrode 3 can be electrically connected in the Y direction.

  As shown in FIG. 1, the first transparent electrode 3 and the second transparent electrode 4 have a shape in which a plurality of rhombus pad portions 21 are arranged vertically or horizontally. In the second transparent electrode 4, the connection portion located at the intersecting portion 18 has a shape narrower than the rhomboid pad portion 21 of the second transparent electrode 4. The bridging electrode 20 is also formed in a strip shape having a narrower width than the diamond-shaped pad portion 21.

  As shown in FIGS. 1 and 2, in the touch panel 1 of the present invention, the above-described coat film 5 of the present invention is formed as a protective film on the first transparent electrode 3 and the second transparent electrode 4. ing. And the formation area and non-formation area | region of the transparent electrode in the part corresponded to the operation area | region of the touch panel 1 are coat | covered. The coat film 5 has high hardness and excellent adhesion to the first transparent electrode 3 and the second transparent electrode 4 made of an inorganic material.

  The coating composition of the present invention described above is used for forming the coating film 5 of the present invention. Specifically, the coating composition obtained by hydrolyzing and condensing the metal alkoxides represented by the above formulas (I) and (II) in an organic solvent in the presence of an aluminum salt, and further adding a precipitation inhibitor. Things are used.

  In the touch panel 1, the refractive index and the film thickness of the coat film 5 can be selected so that the transparent electrode patterns of the first transparent electrode 3 and the second transparent electrode 4 are not visible. Specifically, the refractive index of the coating film 5 is preferably in the range of 1.50 or more and 1.70 or less, and the film thickness is preferably in the range of 40 nm to 170 nm. When the refractive index of the coat film 5 is larger than 1.50 and smaller than 1.60, the film thickness is more preferably in the range of 60 nm to 150 nm. Moreover, when the refractive index of the coat film 5 is in the range of 1.60 or more and 1.70 or less, the film thickness is more preferably in the range of 40 nm to 170 nm.

  In the touch panel 1, for example, the coat film 5 is formed from a coating composition containing silicon alkoxide and titanium alkoxide, and has a refractive index of 1.52 and a film thickness of 100 nm.

  As shown in FIG. 2, the touch panel 1 has an adhesive layer using an acrylic photocurable resin or the like on the surface on which the first transparent electrode 3 and the like are formed and the uppermost layer on the viewing side of the display panel 10. By superimposing via 9, it can be set as one display apparatus. Here, the adhesive layer 9 is provided on the coat film 5.

  Said display apparatus has the touch panel 1 and the display panel 10, and can have a backlight as needed. Although details are omitted in FIG. 2, the display panel 10 can have the same configuration as a known display device. For example, in the case of a liquid crystal display device, the display panel 10 can have a structure in which a liquid crystal layer is sandwiched between two transparent substrates. A polarizing plate can be provided on the side of each transparent substrate opposite to the side in contact with the liquid crystal layer. In addition, a segment electrode or a common electrode can be formed on each transparent substrate in order to control the state of the liquid crystal. The liquid crystal layer is sealed with each transparent substrate and a sealing material.

  As shown in FIG. 1, in the touch panel 1, terminals (not shown) are provided at end portions of the first transparent electrode 3 and the second transparent electrode 4, and a plurality of lead wires 11 are provided from the terminals. Is pulled out. The lead wiring 11 can be an opaque metal wiring using an alloy containing these metals such as Mo—Nb (molybdenum-niobium) alloy in addition to silver, aluminum, chromium, copper, or molybdenum. The lead-out wiring 11 is connected to a control circuit (not shown) that detects voltage application and a touch position to the first transparent electrode 3 and the second transparent electrode 4.

  In the touch panel 1 having the above configuration, a voltage is sequentially applied to the plurality of first transparent electrodes 3 and the second transparent electrodes 4 to give an electric charge. When a finger as a conductor touches any part of the operation region, a capacitor is formed by capacitive coupling between the fingertip and the first transparent electrode 3 and the second transparent electrode 4. Therefore, it is possible to detect which part of the finger touched by capturing the change in the charge at the contact position of the fingertip.

  The touch panel 1 can also selectively apply a voltage to one of the first transparent electrode 3 and the second transparent electrode 4 under the control of a control circuit (not shown). In this case, an electric field is formed on the transparent electrode to which a voltage is applied, and when a finger or the like touches in this state, the contact position is grounded via the capacitance of the human body. As a result, a change in resistance value occurs between the terminal (not shown) of the first transparent electrode 3 or the second transparent electrode 4 as a target and the contact position. Since this resistance value is proportional to the distance between the contact position and the terminal of the first transparent electrode 3 or the second transparent electrode 4 as a target, the contact position and the first transparent electrode 3 or the first transparent electrode 3 as a target. The coordinates of the contact position can be obtained by the control circuit detecting the current value flowing between the two transparent electrodes 4.

  In the touch panel 1 of the present invention, the conspicuous transparent electrode pattern is suppressed in the operation region due to the effect of the coating film 5 provided on the first and second transparent electrodes 3 and 4.

Next, the manufacturing method of the touch panel 1 of this invention is demonstrated.
3A to 3D are process cross-sectional views illustrating a method for manufacturing a touch panel as a first example of the present invention.

  First, a transparent substrate 2 such as a glass substrate is prepared. The substrate 2 is cut into a desired shape and washed as necessary. Next, a transparent conductive film is formed on one surface of the substrate 2. An intermediate layer such as SiOx, SiNx, or SiON may be formed between the substrate 2 and the transparent conductive film. The transparent conductive film is, for example, ITO, and is formed to a thickness of 10 to 200 nm using a sputtering method, a vacuum deposition method, or the like. Next, the transparent conductive film is etched in a state where an etching mask made of a photosensitive resin or the like is formed on the upper layer side of the transparent conductive film, and the first transparent electrode 3 and the second transparent electrode 4 are formed by patterning. By removing the etching mask, a transparent conductive film substrate 14 having a transparent electrode pattern as shown in FIG. 3A is obtained.

  Here, at the intersecting portion 18 of the transparent conductive film substrate 14, the second transparent electrode 4 is connected via a connection portion, but the first transparent electrode 3 is divided.

Next, a photosensitive resin is applied to the side on which the first transparent electrode 3 and the second transparent electrode 4 are provided, and then exposed and developed, whereby an interlayer insulation is formed at the connection portion of the second transparent electrode 4. A film 19 is formed (FIG. 3B). As the photosensitive resin for forming the interlayer insulating film 19, a transparent resin is used. For example, an acrylic resin can be used. When the interlayer insulating film 19 is formed using SiO ₂ , the same structure can be obtained by sputtering using a mask. However, when patterning property is taken into consideration, it is preferable to use an acrylic resin.

  Next, after forming a transparent conductive film on the interlayer insulating film 19, the transparent conductive film is etched with an etching mask made of a photosensitive resin formed on the surface of the transparent conductive film. Thereafter, the etching mask is removed, and a bridging electrode 20 is formed on the interlayer insulating film 19 so as to connect the divided portions of the first transparent electrode 3. Thereby, the structure shown in FIG. 3C is obtained. An example of the transparent conductive film formed on the interlayer insulating film 19 is an ITO film. In that case, the bridging electrode 20 is formed of ITO.

  The lead wiring 11 described above is formed using silver ink or the like in a later step. However, when the transparent conductive film is etched in the above step, the transparent conductive film is left along the outer peripheral edges of the first transparent electrode 3 and the second transparent electrode 4 to form the lead-out wiring 11. Is possible.

  Next, a coating composition for forming a metal oxide layer is applied on the first transparent electrode 3, the second transparent electrode 4, and the bridging electrode 20 by flexographic printing. Here, the coating composition is obtained by hydrolyzing and condensing a metal alkoxide in an organic solvent in the presence of a metal salt (for example, an aluminum salt) and further adding a precipitation inhibitor. Subsequently, the board | substrate 2 with which the coating film of the coating composition was formed is dried on 40-150 degreeC (for example, 60 degreeC), for example on a hotplate. Thereafter, the metal oxide layer 5 is formed on the first transparent electrode 3, the second transparent electrode 4, and the bridging electrode 20 by heating, for example, in an oven at 100 to 300 ° C. (for example, 250 ° C.). . Thereby, the touch panel board | substrate 30 shown in FIG.3 (d) is obtained. In addition, after drying the coating film on the board | substrate 2, for example on a hotplate, after irradiating this coating film with an ultraviolet-ray, you may heat in oven.

  The coating film 5 of the present invention thus obtained has high hardness and high strength with inorganic metal oxide as the main component. In addition, no cracks are generated even on the interlayer insulating film 19 which is an organic film.

  Next, a lead-out wiring 11 is formed with silver ink or the like from end terminals (not shown) of the first transparent electrode 3 and the second transparent electrode 4 to form the touch panel 1. The touch panel 1 is connected to a control circuit (not shown) of the touch panel via the lead wiring 11.

  The completed touch panel 1 is attached to the front surface of the display panel 10 via an adhesive layer 9 such as an acrylic transparent adhesive. At this time, alignment is performed by providing alignment marks at the corners of the substrate 2 and the display panel 10 as necessary.

  In the touch panel 1 attached to the display panel 10, since the coating film 5 is provided, high reliability is realized. And it can suppress that the transparent electrode pattern of the 1st transparent electrode 3 and the 2nd transparent electrode 4 is conspicuous in the operation area | region of the touch panel 1. FIG.

  FIG. 4 is a cross-sectional view showing a schematic configuration of another example of the touch panel of the present invention. As illustrated in FIG. 4, the touch panel 101 includes a transparent substrate 102. A transparent electrode pattern is formed in the operation region of the substrate 102. That is, the first transparent electrode 103 and the second transparent electrode 104 for detecting positions in two different directions are provided on the upper layer of the substrate 102.

  The first transparent electrode 103 and the second transparent electrode 104 are formed using a transparent electrode material that has at least high transmittance for visible light and has conductivity. As such a transparent electrode material having conductivity, for example, ITO or ZnO can be used. When ITO is used, the thickness is preferably 10 to 200 nm so as to ensure sufficient conductivity.

  The first transparent electrode 103 and the second transparent electrode 104 are formed by a transparent substrate 102 as an underlayer or an overcoat to be described later by sputtering, vacuum deposition, ion plating, spraying, dipping or CVD. An optimum method is selected in consideration of the layer 107.

  For example, a transparent electrode formed in a planar shape is patterned by an etching method using photolithography technology, or a coating material in which a conductive filler made of the above material is dispersed in an organic solvent, and directly by a printing method. There is a method of forming a desired pattern. In the transparent electrode forming step, it is preferable that the film thickness can be accurately controlled. Therefore, it is preferable to select a method capable of forming a desired film thickness and forming a low-resistance film excellent in transparency.

  As shown in FIG. 4, the first transparent electrode 103 is disposed on the substrate 102. A coating film 105 of the present invention is formed on the first transparent electrode 103. For the formation of the coating film 105, the above-described coating composition of the present invention is used. The coat film 105 covers the formation region and the non-formation region of the first transparent electrode 103 corresponding to the operation region of the touch panel 101.

  An overcoat layer 107 is provided on the coat film 105. The overcoat layer 107 is a film made of an organic material formed from a highly transparent acrylic resin.

  As shown in FIG. 4, the second transparent electrode 104 is disposed on the overcoat layer 107. On the second transparent electrode 104, the coating film 106 of the present invention is formed. For the formation of the coating film 106, the above-described coating composition of the present invention is used. The coat film 106 covers the transparent electrode forming region and the non-forming region corresponding to the operation region of the touch panel 101. The coat films 105 and 106 have high hardness and excellent adhesion to the first transparent electrode 103 and the second transparent electrode 104. The coat film 106 of the present invention contains an inorganic metal oxide as a main component, but does not cause cracks on the overcoat layer 107. That is, even if the coat film 106 is formed so as to cover the overcoat layer 107 which is a film made of an organic material together with the second transparent electrode 104, no crack is generated inside.

  In the touch panel 101, the refractive index and film thickness of the coating films 105 and 106 can be selected so that the transparent electrode patterns of the first transparent electrode 103 and the second transparent electrode 104 are not visible. Specifically, the refractive indexes of the coating films 105 and 106 are preferably in the range of 1.50 to 1.70 and the film thickness is preferably in the range of 40 nm to 170 nm. And when the refractive index of the coating films 105 and 106 is larger than 1.50 and smaller than 1.60, it is more preferable that a film thickness exists in the range of 60 nm-150 nm. Moreover, when the refractive indexes of the coating films 105 and 106 are in the range of 1.60 or more and 1.70 or less, the film thickness is more preferably in the range of 40 nm to 170 nm.

  In the touch panel 101, for example, the first transparent electrode 103 and the second transparent electrode 104 are each made of ITO having a film thickness of 28 nm. In this case, the coating films 105 and 106 are each formed from the coating composition of the present invention containing silicon alkoxide and titanium alkoxide, and have a refractive index of 1.52 and a film thickness of 100 nm.

  As shown in FIG. 4, an adhesive layer 108 made of an acrylic transparent adhesive is provided on the coat film 106. The display panel 110 is attached to the touch panel 101 via the adhesive layer 108.

  In the touch panel 101 having the above configuration, when a finger that is a conductor touches any part of the operation region, capacitive coupling between the fingertip and the first transparent electrode 103 and the second transparent electrode 104 is performed. To form a capacitor. Therefore, it is possible to detect which part of the finger touched by capturing the change in charge at the contact position of the fingertip.

  In the touch panel 101, high reliability is realized by the effects of the coating films 105 and 106 provided on the first transparent electrode 103 and the second transparent electrode 104. It is also possible to suppress the conspicuous transparent electrode pattern in the operation area.

  5 and 6 are diagrams showing the structure of still another example of the touch panel of the present invention. FIG. 5 is a plan view schematically showing the structure of still another example of the touch panel of the present invention. 6 is a cross-sectional view taken along line B1-B1 'of FIG.

  As shown in FIG. 5, the touch panel 201 is configured using a transparent substrate 202, and a transparent electrode pattern is formed in the operation area of the substrate 202. That is, the first transparent electrode 203 for detecting the coordinate in the X direction formed on one surface of the substrate 202 and the second transparent electrode for detecting the coordinate in the Y direction formed on the other surface of the substrate 202. 204. In the following description, one surface of the substrate 202 is upward and the other surface of the substrate 202 is downward. In this case, the other surface of the substrate 202 is a surface to be attached to the display panel 210.

  The substrate 202 is a dielectric substrate. As the material of the substrate 202, a transparent material such as glass, acrylic resin, polyester resin, polyethylene terephthalate resin, polycarbonate resin, polyvinylidene chloride resin, polymethyl methacrylate resin, polyethylene naphthalate resin, or triacetyl cellulose resin is used. In particular, it is preferable to select a material having heat resistance and chemical resistance suitable for forming the coating films 205 and 206 of the present invention. The thickness of the substrate 202 can be about 0.1 mm to 2 mm for glass, and can be 10 μm to 2000 μm for a resin film.

  As shown in FIG. 5, each of the first transparent electrode 203 and the second transparent electrode 204 is an elongated rectangular electrode. The first transparent electrode 203 extends in the Y direction, and the second transparent electrode 204 extends in the X direction. The first transparent electrode 203 is arranged in a stripe shape at regular intervals. The first transparent electrode 203 and the second transparent electrode 204 are disposed so as to be orthogonal to each other, and have a lattice shape as a whole.

  The first transparent electrode 203 and the second transparent electrode 204 are formed using a transparent electrode material that has at least high transmittance for visible light and has conductivity. As such a transparent electrode material having conductivity, for example, ITO or ZnO can be used. When ITO is used, the thickness is preferably 10 to 200 nm so as to ensure sufficient conductivity.

  The first transparent electrode 203 and the second transparent electrode 204 are optimal in consideration of the transparent substrate 202 as a base from sputtering, vacuum deposition, ion plating, spraying, dipping or CVD. It is formed by selecting a proper method.

  For example, a transparent electrode formed in a planar shape is patterned by an etching method using photolithography, or directly by a printing method using a paint in which a conductive filler made of the above material is dispersed in an organic solvent. There is a method of forming the pattern. In the transparent electrode forming step, it is important to be able to control the film thickness with high accuracy. Therefore, it is preferable to select a method capable of forming a desired film thickness and forming a low-resistance film excellent in transparency.

  As shown in FIGS. 5 and 6, a coat film 205 is formed on the first transparent electrode 203. The coat film 205 covers the transparent electrode forming region and the non-forming region corresponding to the operation region of the touch panel 201. Further, as shown in FIG. 6, a coat film 206 is also formed on the second transparent electrode 204 (below in the drawing). The coat film 206 covers the transparent electrode forming region and the non-forming region corresponding to the operation region of the touch panel 201. The coating films 205 and 206 are high in hardness and excellent in adhesion with the first transparent electrode 203 and the second transparent electrode 204.

  For the formation of the coating films 205 and 206, the above-described coating composition of the present invention obtained by hydrolyzing and condensing metal alkoxide in an organic solvent in the presence of an aluminum salt and further adding a precipitation inhibitor is used. It is done.

  In the touch panel 201, the refractive indexes and film thicknesses of the coating films 205 and 206 can be selected so that the transparent electrode patterns of the first transparent electrode 203 and the second transparent electrode 204 are not visible. Specifically, the refractive indices of the coat films 205 and 206 are each preferably greater than 1.50 and not greater than 1.70, and the film thicknesses are preferably within the range of 40 nm to 170 nm, respectively. And when the refractive index of the coating films 205 and 206 is larger than 1.50 and smaller than 1.60, it is more preferable that the film thickness is in the range of 60 nm to 150 nm. Moreover, when the refractive indexes of the coat films 205 and 206 are in the range of 1.60 or more and 1.70 or less, the film thickness is more preferably in the range of 40 nm to 170 nm.

  In the touch panel 201, for example, the first transparent electrode 203 and the second transparent electrode 204 are each made of ITO having a film thickness of 28 nm. In this case, the coat films 205 and 206 are each formed from a coating composition prepared using silicon alkoxide and titanium alkoxide, and have a refractive index of 1.52 and a film thickness of 100 nm.

  As shown in FIG. 6, an adhesive layer 208 made of an acrylic transparent adhesive is provided on one surface of the substrate 202. A cover film 207 made of a transparent resin is bonded on the adhesive layer 208. In FIG. 5, the cover film 207 is omitted.

The cover film 207 functions as a protective film for the first transparent electrode 203 and the coat film 205. Instead of the cover film 207, a transparent resin may be coated. In this case, the adhesive layer 208 can be omitted.
The display panel 110 is attached to the other surface of the substrate 202 via an adhesive layer 209 made of an acrylic transparent adhesive.

  Although details are omitted in FIG. 6, the display panel 210 can have the same configuration as a known display device. For example, in the case of a liquid crystal display device, the display panel 210 can have a structure in which a liquid crystal layer is sandwiched between two transparent substrates. A polarizing plate can be provided on the side of each transparent substrate opposite to the side in contact with the liquid crystal layer. In addition, a segment electrode or a common electrode can be formed on each transparent substrate in order to control the state of the liquid crystal. The liquid crystal layer is sealed with each transparent substrate and a sealing material.

  In the touch panel 201, terminals (not shown) are provided at the ends of the first transparent electrode 3 and the second transparent electrode 4, and a plurality of lead wires (not shown) are drawn from the terminals. . The lead-out wiring can be an opaque metal wiring using silver, aluminum, chromium, copper or an alloy containing these. The lead-out wiring is connected to a control circuit (not shown) that detects the touch position and voltage application to the first transparent electrode 203 and the second transparent electrode 204.

  In the touch panel 201 having the above configuration, when a finger that is a conductor touches any part of the operation region, capacitive coupling between the fingertip and the first transparent electrode 203 and the second transparent electrode 204 is achieved. To form a capacitor. Therefore, it is possible to detect which part of the finger touched by capturing the change in charge at the contact position of the fingertip.

  In the touch panel 201, the effect of the coating films 205 and 206 provided on the first transparent electrode 203 and the second transparent electrode 204 is suppressed from conspicuous in the operation region.

  As described above, in another example of the touch panel of the present embodiment, unlike the above example, a structure in which the coating film of the present invention is provided on an organic film made of an acrylic resin, such as an interlayer insulating film or an overcoat layer. It is not. The coating film of the present invention effectively functions as a protective film for high-strength electrodes even for such touch panel examples. And it prevents that a transparent electrode pattern stands out.

  The touch panel of the present invention has been described above, but the present invention is not limited to the above embodiment. For various types of touch panels using transparent electrodes such as ITO, the coating film of the present invention can be applied as a protective film on the transparent electrodes. And high reliability is realized. In addition, the conspicuousness of the transparent electrode can be suppressed. At that time, even if the coating film of the present invention is formed on various organic films provided in the touch panel, cracks and the like are not generated inside.

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail according to an Example, this invention is not limited to these.

[Abbreviations used in Examples]
The meanings of the abbreviations used in the following examples are as follows.
TEOS: tetraethoxysilane C18: octadecyltriethoxysilane MPS: γ-mercaptopropyltrimethoxysilane GPS: γ-glycidoxypropyltrimethoxysilane UPS: γ-ureidopropyltriethoxysilane APS: γ-aminopropyltriethoxysilane ACPS : Γ-acryloxypropyltrimethoxysilane MPMS: γ-methacryloxypropyltrimethoxysilane MTES: methyltriethoxysilane TIPT: tetraisopropoxytitanium AN: aluminum nitrate nonahydrate EG: ethylene glycol HG: 2-methyl-2 , 4-Pentanediol (also known as hexylene glycol)
BCS: 2-butoxyethanol (also known as butyl cellosolve)
IPA: 2-propanol

<Synthesis Example 1> (Synthesis of Coating Composition K1)
In a 200 mL flask, 12.7 g of AN and 3.0 g of water were added and stirred to dissolve AN. EG 13.6g, HG 38.8g, BCS 36.8g, TEOS 21.7g, GPS 10.6g was put there, and it stirred for 30 minutes under room temperature conditions, and obtained A1 liquid.

In a 300 mL volumetric flask, 4.7 g of TIPT was put as titanium alkoxide, 58.2 g of HG was added thereto, and the mixture was stirred for 30 minutes at room temperature to obtain A2 liquid.
Subsequently, the above-mentioned A1 liquid and A2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K1.

<Synthesis Example 2> (Synthesis of Coating Composition K2)
In a 200 mL flask, 12.7 g of AN and 3.0 g of water were added and stirred to dissolve AN. EG 13.7g, HG 39.2g, BCS 37.3g, TEOS 21.7g, MPS 8.8g was put there, and it stirred for 30 minutes under room temperature conditions, and obtained B1 liquid.

In a 300 mL volumetric flask, 4.7 g of TIPT was added as titanium alkoxide, 58.9 g of HG was added thereto, and the mixture was stirred for 30 minutes at room temperature to obtain B2 liquid.
Subsequently, the above-mentioned B1 liquid and B2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K2.

<Synthesis Example 3> (Synthesis of Coating Composition K3)
In a 200 mL flask, 12.7 g of AN and 3.0 g of water were added and stirred to dissolve AN. EG 13.6g, HG 38.8g, BCS 36.9g, TEOS 21.7g, ACPS 10.5g was put there, and it stirred under room temperature conditions for 30 minutes, and obtained C1 liquid.

In a 300 mL volumetric flask, 4.7 g of TIPT as titanium alkoxide was added, 58.2 g of HG was added thereto, and the mixture was stirred at room temperature for 30 minutes to obtain C2 solution.
Subsequently, the above-mentioned C1 liquid and C2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K3.

<Synthesis Example 4> (Synthesis of Coating Composition K4)
In a 200 mL flask, 12.7 g of AN and 3.0 g of water were added and stirred to dissolve AN. EG 13.5g, HG 38.6g, BCS 36.7g, TEOS 21.7g, MPMS 11.1g was put there, and it stirred under room temperature conditions for 30 minutes, and obtained D1 liquid.

In a 300 mL flask, 4.7 g of TIPT and 57.9 g of HG were added and stirred for 30 minutes at room temperature to obtain a D2 solution.
Subsequently, the above-mentioned D1 liquid and D2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K4.

<Synthesis Example 5> (Synthesis of Coating Composition K5)
In a 200 mL flask, 12.7 g of AN and 3.0 g of water were added and stirred to dissolve AN. EG 13.9g, HG 39.7g, BCS 37.7g, TEOS 15.5g, MTES 13.3g was put there, and it stirred for 30 minutes under room temperature conditions, and obtained E1 liquid.

In a 300 mL flask, 4.7 g of TIPT and 59.5 g of HG were added and stirred for 30 minutes at room temperature to obtain a liquid E2.
Subsequently, the above-mentioned E1 liquid and E2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K5.

<Synthesis Example 6> (Synthesis of Coating Composition K6)
In a 200 mL flask, 12.7 g of AN and 3.0 g of water were added and stirred to dissolve AN. EG 13.4g, HG 38.3g, BCS 36.4g, TEOS 21.7g, MPMS 9.3g, C18 3.1g was put there, and it stirred for 30 minutes at room temperature conditions, and obtained F1 liquid .

In a 300 mL flask, 4.7 g of TIPT and 57.4 g of HG were added and stirred for 30 minutes at room temperature to obtain an F2 solution.
Subsequently, the above-mentioned F1 liquid and F2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K6.

<Synthesis Example 7> (Synthesis of Coating Composition K7)
In a 200 mL flask, 12.7 g of AN and 3.0 g of water were added and stirred to dissolve AN. EG 13.5g, HG 38.6g, BCS 36.7g, TEOS 15.5g, APS 1.7g, ACPS 6.7g, GPS 8.8g was put there, and it stirred for 30 minutes under room temperature conditions. G1 liquid was obtained.

In a 300 mL flask, 4.7 g of TIPT and 57.9 g of HG were added and stirred for 30 minutes at room temperature to obtain a G2 solution.
Subsequently, the above-mentioned G1 liquid and G2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K7.

<Synthesis Example 8> (Synthesis of Coating Composition K8)
In a 200 mL flask, 12.7 g of AN and 3.0 g of water were added and stirred to dissolve AN. EG 13.5g, HG 38.5g, BCS 36.6g, TEOS 15.5g, MPS 1.5g, ACPS 10.5g, UPS 5.9g was put there, and it stirred for 30 minutes under room temperature conditions, An H1 solution was obtained.

In a 300 mL flask, 4.7 g of TIPT and 57.7 g of HG were added and stirred for 30 minutes at room temperature to obtain an H2 solution.
Subsequently, the above-mentioned H1 liquid and H2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K8.

<Synthesis Example 9> (Synthesis of Coating Composition K9)
In a 200 mL flask, 13.1 g of AN and 3.1 g of water were added and stirred to dissolve AN. EG 13.3g, HG 95.2g, BCS 36.2g, TEOS 16.3g, MPMS 22.8g was put there, and it stirred under room temperature conditions for 30 minutes. This obtained coating composition K9.

<Synthesis Example 10> (Synthesis of Coating Composition K10)
In a 200 mL flask, 12.1 g of AN and 2.8 g of water were added and stirred to dissolve AN. EG 13.5g, HG 56.7g, BCS 36.8g, TEOS 13.7g, MPMS 10.9g was put there, and it stirred for 30 minutes under room temperature conditions, and obtained I1 liquid.

In a 300 mL flask, 13.4 g of TIPT and 40.1 g of HG were put, and stirred for 30 minutes at room temperature to obtain a liquid I2.
Subsequently, the above-mentioned I1 liquid and I2 liquid were mixed and stirred for 30 minutes at room temperature. This obtained coating composition K10.

<Synthesis Example 11> (Synthesis of Coating Composition K11)
In a 200 mL flask, 11.8 g of AN and 2.8 g of water were added and stirred to dissolve AN. EG 13.6g, HG 44.8g, BCS 36.8g, TEOS 10.5g, MPMS 10.3g was put there, and it stirred for 30 minutes under room temperature conditions, and obtained J1 liquid.

In a 300 mL flask, 17.4 g of TIPT and 52.1 g of HG were put, and stirred for 30 minutes at room temperature to obtain a solution J2.
Subsequently, the above-mentioned J1 liquid and J2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K11.

<Synthesis Example 12> (Synthesis of Coating Composition K12)
In a 200 mL flask, 11.5 g of AN and 2.7 g of water were added and stirred to dissolve AN. EG 13.6g, HG 33.5g, BCS 36.9g, TEOS 7.2g, and MPMS 10.0g were put there, and it stirred under room temperature conditions for 30 minutes, and obtained L1 liquid.

In a 300 mL flask, 21.2 g of TIPT and 63.6 g of HG were put, and stirred at room temperature for 30 minutes to obtain a liquid L2.
Subsequently, the above-mentioned L1 liquid and L2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K12.

<Synthesis Example 13> (Synthesis of Coating Composition K13)
In a 200 mL flask, 12.7 g of AN and 3.0 g of water were added and stirred to dissolve AN. EG 13.7g, HG 39.1g, BCS 37.1g, and TEOS 31.1g were put there, and it stirred under room temperature conditions for 30 minutes, and obtained M1 liquid.

In a 300 mL flask, 4.7 g of TIPT and 58.6 g of HG were placed, and stirred at room temperature for 30 minutes to obtain a liquid M2.
Subsequently, the above-mentioned M1 liquid and M2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K13. The coating composition K13 does not contain the metal alkoxide having the structure represented by the general formula (II).

<Synthesis Example 14> (Synthesis of Coating Composition K14)
In a 200 mL flask, 12.7 g of AN and 3.0 g of water were added and stirred to dissolve AN. EG 13.7g, HG 39.2g, BCS 37.3g, TEOS 28.0g, and MTES 2.7g were put there, and it stirred under room temperature conditions for 30 minutes, and obtained N1 liquid.

In a 300 mL flask, 4.7 g of TIPT and 58.8 g of HG were put, and stirred for 30 minutes at room temperature to obtain N2 liquid.
Subsequently, the above-mentioned N1 liquid and N2 liquid were mixed, and it stirred for 30 minutes under room temperature conditions. This obtained coating composition K14.
Compared with the coating compositions K1 to K12 of Synthesis Examples 1 to 12 described above, the coating composition K13 contains only a small amount of the metal alkoxide having the structure represented by the general formula (II). .

<Synthesis Example 15> (Synthesis of Coating Composition K15)
In a 200 mL flask, 12.7 g of AN and 3.0 g of water were added and stirred to dissolve AN. IPA 145.6g, TEOS 15.5g, MPMS 18.5g, and TIPT 4.7g were put there, and it stirred under room temperature conditions for 30 minutes. This obtained coating composition K15.

<Evaluation of stability>
About the coating composition by the synthesis example mentioned above, coating composition K1-K12 and K15 are made into stability of Reference Example 1 , Examples 2-4 , Reference Example 5, Examples 6-12, and Comparative Example 1, respectively. Evaluation was performed.
As a method for evaluating stability, the synthesized coating composition (K1 to K12, K15) is used, subjected to pressure filtration with a membrane filter having a pore diameter of 0.5 μm, and then allowed to stand at room temperature for one week. Subsequently, when a film was formed on the silicon substrate (100) by spin coating, the case where no foreign matter was observed on the coating film on the silicon substrate was evaluated as “Good”, and the case where foreign matter was observed was evaluated as “X”. The evaluation results are shown in Table 1.

<Method I for Coating Film I>
Using the coating composition according to the synthesis example described above, pressure filtration is performed with a membrane filter having a pore size of 0.5 μm, and a coating film is formed on the substrate by spin coating. The substrate is heated for 3 minutes on a hot plate set to 60 ° C. and dried. Next, using an ultraviolet irradiation device (UB011-3A type manufactured by Eye Graphics Co., Ltd.), using a high-pressure mercury lamp (input power supply 1000 W), ultraviolet irradiation is performed for 2 minutes at a light intensity of 50 mW / cm ² (wavelength 365 nm conversion). . The amount of ultraviolet irradiation is 6000 mJ / cm ² . After the ultraviolet irradiation, it is transferred into a hot air circulation oven set at 250 ° C. and baked for 30 minutes. Thus, a coat film is formed on the substrate.

<Method II of Coating Film Formation>
Using the coating composition according to the synthesis example described above, pressure filtration is performed with a membrane filter having a pore size of 0.5 μm, and a coating film is formed on the substrate by spin coating. The substrate is heated for 3 minutes on a hot plate set to 60 ° C. and dried. Next, it is transferred into a hot air circulation oven set at 250 ° C. and baked for 30 minutes. Thus, a coat film is formed on the substrate.

The method for forming the coating film of this example using the coating composition of this example has been described above. Next, the evaluation of the coating film of this example will be described. At this time, with the coating composition K1~K8 by synthesis examples described above, on a suitable substrate, the film forming method in Reference Example co over preparative film coat film deposited (KL1~KL8) by I 13, It is set as Examples 14-16, Reference Example 17, and Examples 18-20 . Then, the coating films (KL9 to KL12) formed by the above-described film forming method II on the appropriate substrate using the coating compositions K9 to K12 according to the synthesis examples described above are used as the coating films according to the embodiments 21 to 24 of the present invention. And In addition, a coating film (KM2) formed by the above film forming method II on a suitable substrate using the coating composition K13 according to the synthesis example described above is referred to as a comparative example 2 of the coating film.

<Evaluation of refractive index>
A silicon substrate (100) was used as the substrate. As described above, the coating film of Reference Example 13, Examples 14 to 16, Reference Example 17, and Examples 18 to 20 formed on the silicon substrate by the film forming method I, and formed by the film forming method II. The coated films of Examples 21 to 24 and the coated films of Comparative Example 2 and Comparative Example 3 formed by the film forming method II were formed, and the refractive index was evaluated. The evaluation method was performed by measuring the refractive index at a wavelength of 633 nm using an ellipsometer (DVA-FLVW, manufactured by Mizoji Optical Co., Ltd.).
The evaluation results of each coat film are shown in Table 2 below together with the coating composition used for forming each coat film.

<Crack evaluation>
An acrylic film having a thickness of 2 μm was formed on the glass substrate. The acrylic film was formed as follows. First, the acrylic material composition was filtered under pressure with a membrane filter having a pore size of 0.5 μm, and a coating film was formed on the entire surface of the glass substrate by a spin coating method. Next, this substrate was heated and dried for 2 minutes on a hot plate, then transferred to a hot-air circulating oven and baked for 30 minutes. As a result, an acrylic film was formed on the glass substrate.

A coat film having a thickness of 100 nm is formed on the acrylic film by the film formation method I or the film formation method II.
And by the coating film of the reference example 13, Examples 14-16, Reference example 17, and Examples 18-20 formed by the film-forming method I on the glass substrate in which the acrylic film was formed, by the film-forming method II The formed coating films of Examples 21 to 24 and the coating film of Comparative Example 2 formed by the film forming method II were formed, and the coating film was evaluated for cracks.

Regarding the evaluation criteria for crack evaluation, in the coating film on the substrate, those that do not cause cracks are evaluated as ◎, those that do not occur in the plane but cracks only at the edges are evaluated as ○, and those that cause cracks on the entire surface are × It was evaluated.
As a result of the evaluation, it was found that the coating films of Reference Example 13, Examples 14 to 16, Reference Example 17, and Examples 18 to 24 were improved in the generation of cracks as compared with the coating film of Comparative Example 2.

<Transparent conductive film substrate>
A transparent conductive film substrate on which a patterned transparent conductive film is formed on a substrate is prepared. A glass substrate is used as the substrate, and ITO is used as the transparent conductive film. As this transparent conductive film substrate, the transparent conductive film substrate 14 used in the touch panel 1 of the present invention described above can be used. Here, the film thickness of ITO was 28 nm.

<Production of touch panel>
A substrate in which the coating film KL8 of Example 20 was formed to a thickness of 100 nm on the transparent conductive film substrate having a thickness of ITO of 28 nm was produced. An optical adhesive was applied onto the substrate, and 0.7 mm of raw glass was bonded. Next, UV irradiation is performed for 80 seconds at a light intensity of 50 mW / cm ² (converted to a wavelength of 365 nm) using a high-pressure mercury lamp (input power supply 1000 W) using an ultraviolet irradiation device (UB011-3A type manufactured by Eye Graphics Co., Ltd.). did. Thereby, the optical adhesive was hardened and the touch panel of Example 25 was produced as a touch panel for characteristic evaluation.

  Next, a touch panel of Example 26 was produced by the same production method as above except that the coat film KL10 of Example 22 was used instead of KL8 of Example 20. Further, a touch panel of Example 27 was produced by the same production method as described above except that the coat film KL11 of Example 23 was used instead of KL8 of Example 20. Further, a touch panel of Example 28 was produced by the same production method as above except that the coat film KL12 of Example 24 was used instead of KL8 of Example 20.

  Further, on the transparent conductive film substrate, a coating film was formed by the film forming method I using the coating composition K12, and the rest was the same as in the case of Example 25, and the touch panel of Example 29 was used. Was made. In addition, the refractive index measured with the evaluation method similar to the above about the coating film formed into a film by the film-forming method I using coating composition K12 was 1.70.

  Then, for comparative evaluation, a touch panel of Comparative Example 3 was produced by the same production method as described above except that the coat film KM2 of Comparative Example 2 was used instead of KL8 of Example 20 as the coat film. Moreover, the touchscreen of the comparative example 4 was produced by the production method similar to the above except that the transparent conductive film substrate described above was used and no coating film was formed. Therefore, the evaluation touch panel of Comparative Example 4 has no coating film formed on the transparent electrode.

<Evaluation of electrode pattern appearance>
Using the evaluation touch panels of Example 25 to Example 29 and Comparative Examples 3 and 4, evaluation of whether the electrode pattern of ITO is conspicuous was performed, and evaluation of the appearance of the electrode pattern was performed.

As an evaluation method, each touch panel was placed on a black cloth and visually observed with the light illuminated from above. And in the touch panel of the comparative example 4, after confirming that a transparent electrode pattern is visible, another touch panel is observed. As a result of these observations, a transparent electrode pattern that could not be seen was evaluated as ◎. And although the transparent electrode pattern can be seen, the degree of improvement compared to the touch panel of Comparative Example 4 that does not have a coating film is evaluated as “Good”, and the one that is not improved compared to the touch panel of Comparative Example 4 is × It was evaluated.
Table 3 shows the results of the electrode pattern appearance evaluation for the evaluation touch panels of Examples 25 to 29 and Comparative Examples 3 and 4.

As a result of the above evaluation, it was found from Table 1 that the stability of the coating composition was improved by including a metal nitrate and a precipitation inhibitor.
From Table 2, by controlling the structure and composition of the metal alkoxide contained in the coating composition appropriately, the coating film formed therefrom is a stable film that does not crack even on an organic thin film made of an acrylic resin or the like. Was found to be formed.

From Table 3, it was found that the appearance of the electrode pattern can be suppressed on the touch panel by forming a coat film having an appropriately controlled refractive index on the electrode.
Each of the coating films of the present example has a hardness of 5H or more, which is significantly higher than that of a general organic acrylic material less than 3H.

  The coating composition of the present invention can provide a high-strength coat film with a controlled refractive index, and the electrode pattern does not stand out on a touch panel using the coat film. Therefore, it is useful as a touch panel for a display device that requires excellent appearance and high reliability.

  In addition, the entire content of the specification, claims, drawings and abstract of Japanese Patent Application No. 2011-010164 filed on January 20, 2011 is cited here as disclosure of the specification of the present invention. Incorporated.

1, 101, 201 Touch panel 2, 102, 202 Substrate 3, 103, 203 First transparent electrode 4, 104, 204 Second transparent electrode 5, 6, 105, 106, 205, 206 Coat film 9, 108, 208 , 209 Adhesive layer 10, 110, 210 Display panel 11 Lead-out wiring 14 Transparent conductive film substrate 18 Crossing portion 19 Interlayer insulating film 20 Cross-linked electrode 21 Pad portion 30 Touch panel substrate 107 Overcoat layer 207 Cover film

Claims (11)

A coating composition for forming a coating film on at least a part of a transparent electrode in a touch panel having a transparent electrode pattern in an operation region of a substrate, the first metal alkoxide represented by the following general formula (I) And a second metal alkoxide represented by the following general formula (II), a metal salt represented by the following general formula (III), an organic solvent, water, and a precipitation inhibitor , the content of the second metal alkoxide, based on the total metal alkoxide combined first metal alkoxide and a second metal alkoxide, a touch panel for a coating composition, characterized in 15 to 80 mole% der Rukoto.
M ¹ (OR ¹ ) _n (I)
(Wherein M ¹ is a group consisting of silicon (Si), titanium (Ti), tantalum (Ta), zirconium (Zr), boron (B), aluminum (Al), magnesium (Mg) and zinc (Zn). R ¹ represents an alkyl group having 1 to 5 carbon atoms, and n represents a valence 2 to 5 of M ¹ .
R ² _l M ² (OR ³ ) _ml (II)
(Wherein M ¹ is a group consisting of silicon (Si), titanium (Ti), tantalum (Ta), zirconium (Zr), boron (B), aluminum (Al), magnesium (Mg) and zinc (Zn). It represents at least one metal selected from .R ² is main mercapto group, methacryloxy group, acryloxy group, was or is substituted with a ureido group, and, carbon atoms which may have a hetero atom 1 R ³ represents an alkyl group having 1 to 5 carbon atoms, m represents a valence 2 to 5 of M ² , and 1 represents 1 when m has a valence of 3. Or 2 when the valence of m is 4, and 1 to 4 when the valence of m is 5.
M ³ (X) _k (III)
(Wherein M ³ represents aluminum (Al), indium (In), zinc (Zn), zirconium (Zr), bismuth (Bi), lanthanum (La), tantalum (Ta), yttrium (Y) and cerium ( Ce) represents at least one metal selected from the group consisting of: X is a residue of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, succinic acid, sfamic acid, sulfonic acid, acetoacetic acid or acetylacetonate, or their basicity Represents a salt, and k represents the valence of M ^3. ) Precipitation inhibitor, N- methyl - pyrrolidone, ethylene glycol, dimethylformamide, dimethylacetamide, diethylene glycol, propylene glycol, hexylene glycol and of claim 1 is at least one or more selected from the group consisting of derivatives Coating composition for touch panel. The molar ratio of the metal atom (M ³ ) of the metal salt to the metal atoms (M ¹ and M ² ) of the first metal alkoxide and the second metal alkoxide is:
0.01 ≦ M ³ / (M ¹ + M ² + M ³ ) ≦ 0.7
The coating composition for a touch panel according to claim 1 or 2 . The coating composition for a touch panel according to any one of claims 1 to 3 , wherein the first metal alkoxide is a mixture of silicon alkoxide or a partial condensate thereof and titanium alkoxide.
The metal salt is a metal nitrate, metal sulfate, metal acetate, metal chloride, metal oxalate, metal sphamate, metal sulfonate, metal acetoacetate, metal acetylacetonate or a basic salt thereof. The coating composition for touchscreens in any one of Claims 1-4 . The organic solvents are alkylene glycols or coating composition according to any one of claims 1 to 5 including the mono-ether derivatives. The coating film formed into a film using the coating composition for touchscreens in any one of Claims 1-6 . The coating film according to claim 7 , wherein the refractive index is 1.52 to 1.70 and the film thickness is 40 nm to 170 nm. A touch panel in which a transparent electrode pattern is formed in an operation region of a substrate, wherein the coating film according to claim 7 or 8 is disposed on at least a part of the transparent electrode pattern. The transparent electrode pattern includes a first transparent electrode pattern for detecting positions in at least two different directions, and a second transparent electrode pattern,
At least a part of the first transparent electrode pattern and the second transparent electrode pattern overlap each other in the operation region of the substrate, and the first transparent electrode pattern and the second transparent electrode in the overlapping part A film made of organic material is placed between the pattern and
The touch panel according to claim 9 , wherein the coating film is configured to cover at least a part of the film made of the organic material together with at least a part of the first transparent electrode pattern or the second transparent electrode pattern.   There are a plurality of overlapping portions of the first transparent electrode pattern and the second transparent electrode pattern in the operation region of the substrate, and each of the overlapping portions has an area larger than the area of the overlapping portion. The touch panel according to claim 10, wherein a film made of the organic material is arranged.

Images