JP2000094592A - Transparent conductive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive film excellent in durability to input, which can prevent generating of interference on a display, and generating of sticking and a Newton's ring. SOLUTION: A resin layer (a hard-coated layer) is formed on at least one side of a transparent base film by applying directly or with another layer therebetween a coating containing at least a resin and fine particles having an average particle diameter of 1500 nm (and particles having an average particle diameter of 0.620 μm can be contained). A transparent conductive layer is provided on the resin layer directly or with another layer therebetween.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent conductive film, and more particularly to a transparent conductive film which is applied to touch panels and the like, has excellent durability and visibility on a display, and is particularly effective for preventing sticking and Newton's ring. Related to a functional film.

[0002]

2. Description of the Related Art In recent years, a transparent touch panel using a transparent conductive film has been widely used. The transparent touch panel inputs predetermined information and the like to a computer or the like by pressing a predetermined position with a finger or a pen. When input is repeated with a finger or a pen, the resistance value of the transparent conductive film gradually changes and information or the like cannot be input accurately.Also, when pressing a predetermined position with a finger or a pen, a transparent conductive layer of a transparent conductive film, Contact with the opposing transparent conductive layer,
Due to the repeated non-contact, distortion or the like is generated, which causes a problem such as the occurrence of Newton's ring. Therefore, it has been proposed to form a coating layer of an organic resin containing a filler and form a transparent conductive layer thereon. However, when a transparent conductive film is formed through a coating layer of an organic resin containing a filler, although there is an effect of preventing Newton's ring, the adhesion between the coating layer and the transparent conductive film is insufficient or
Because the film hardness of the organic resin coating layer is weak,
The input durability was poor and not satisfactory. Also,
When a coating layer containing a filler is provided, especially when used on a color display, it depends on the pitch of the color filter, but there is a problem that the filler causes dot-like interference and visibility is poor. .

[0003]

Accordingly, the present invention has excellent input durability, prevents occurrence of interference on a display,
Provided is a transparent conductive film which prevents sticking and Newton's ring from occurring.

[0004]

That is, the present invention relates to a transparent base material film (A.), which has at least one resin and an average particle diameter of 1 to 5 directly or through another layer.
A resin layer (B.) containing fine particles of 00 nm, and a transparent conductive layer (C.) provided directly or via another layer on the resin layer (B.). The transparent conductive film, wherein the resin layer (B.) is a hard coat layer, wherein the resin layer (B.) also contains particles having an average particle size of 0.6 to 20 μm. Film. Also, the particles are 0.0
5 to 30% by weight, fine particles are 0.001 to
90% by weight of the above-mentioned transparent conductive film which is a resin layer (B.), and further on the side opposite to the side on which the transparent conductive layer (C.) of the base film (A.) is provided. The transparent conductive film described above, on which a hard coat layer (D.) is formed.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The base film (A.) used in the present invention is not particularly limited, but it is preferable to use a film having high transparency in view of workability and application. Cellulose resins such as cellulose triacetate and acetate, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acrylic resins such as polymethyl methacrylate, and artificial resins such as polycarbonate resins can be used. preferable. Further, on the base film (A.),
Resin layer (M.) for improving adhesion between base film (A.) and resin layer (B.) or hard coat layer (D.)
May be formed.

The resin layer (B.) used in the present invention is not particularly limited in its resin, but it is preferable that the resin layer (B.) after formation has improved durability as a transparent conductive film and has an affinity with fine particles. A hard coat layer having a pencil hardness of H or more from the viewpoint of properties and the like, and a resin layer (B.) as the hard coat layer will be described below. The hard coat layer described below therefore also includes the hard coat layer (D.). The hard coat resin used for the resin layer (B.), that is, the hard coat paint for forming the hard coat layer (B. and D.) is mainly a thermosetting resin,
Alternatively, an ionizing radiation-curable resin is conceivable. Among them, it is preferable to use an ionizing radiation-curable resin in view of work environment and productivity. The hard coat layer (D.) may or may not contain the fine particles. The resin layer (B.) and the hard coat layer (D.)
Is not particularly limited, but is in the range of 0.3 to 10 μm from the balance between transparency and durability. The ionizing radiation-curable resin is formed from a paint containing at least a resin that is cured by irradiation with an electron beam or ultraviolet rays.
Specifically, it contains a photopolymerizable prepolymer, a photopolymerizable monomer, and a photopolymerization initiator, and further contains, if necessary, additives such as a sensitizer, a non-reactive resin, and a leveling agent, and a solvent. It is. The structure and molecular weight of the photopolymerizable prepolymer relate to the curing of the ionizing radiation-type curable coating material, and determine properties such as hardness and crack resistance.
The photopolymerizable prepolymer is generally of a type which undergoes radical polymerization by irradiating an acryloyl group introduced into a skeleton with ionizing radiation. Those cured by radical polymerization are particularly preferred because they have a high curing rate and a high degree of freedom in resin design. As the photopolymerizable prepolymer, an acrylic prepolymer having an acryloyl group is particularly preferable, and an acrylic prepolymer having two or more acryloyl groups in one molecule and having a three-dimensional network structure is preferable. As the acrylic prepolymer, urethane acrylate, melamine acrylate, polyester acrylate, and the like can be used. The photopolymerizable monomer is used for diluting a high-viscosity photopolymerizable prepolymer, lowering the viscosity and improving workability, and for imparting coating strength as a crosslinking agent. Further, when the amount of the photopolymerizable monomer increases, the coating film becomes harder than necessary. Therefore, the mixing ratio is preferably selected so that a desired hardness or a desired flexibility can be obtained.

The particle size of the particles used for preventing Newton's ring in the present invention is preferably as small as possible in order to suppress image deterioration, but in order to obtain a sufficient Newton's ring preventing effect due to unevenness on the surface, the average particle size is preferably 0%. It is necessary to be not less than 0.6 μm and not more than 20 μm.

The particles used in the present invention are not particularly limited, but include silica, silicone resin particles, acrylic resin particles, styrene resin particles, nylon resin particles and the like, and the shape of the particles is spherical or nearly spherical. Is preferred. The amount of particles added to prevent Newton's rings is affected by the specific gravity of the particles used, but is usually in the range of 0.05 to 30% by weight, preferably 0.2 to 5% by weight of the resin solids. It is. In the present invention, the thickness of the hard coat layer containing the particles is not more than the average particle size of the particles, preferably not more than 80% of the average particle size. Although depending on the particle size distribution, if the hard coat layer is thicker than 80% of the average particle size, most of the particles are buried in the hard coat layer, and a sufficient Newton ring preventing effect cannot be obtained. Further, in order to prevent the loss of particles, the average particle diameter is desirably 50% or more.

According to the present invention, the input durability of the transparent conductive film is improved,
When adding particles to the resin layer to prevent Newton's ring, fine particles are added to the resin layer to prevent interference on a color display, and the fine particles have an average particle diameter of 1 to 500 nm. In particular, fine particles having an average particle diameter of 5 to 200 nm are preferably used. If the average particle size exceeds 500 nm, the transmittance tends to be impaired. Handling properties,
Considering the adhesion to the transparent conductive film, a metal oxide sol prepared from a hydrolyzate of a metal alkoxide or the like and in which inorganic oxide fine particles are dispersed in a colloidal form is preferable. More preferably, the colloidally dispersed fine particles are stabilized using a dispersant or the like. Examples of the inorganic oxide fine particles include silicon oxide, antimony oxide, tin oxide, indium oxide, zinc oxide, alumina, titania, and zirconia. Among them, colloidal silica in which silicon oxide is dispersed is preferable in consideration of price and color. In order to enhance the conductive effect of the transparent conductive layer, tin oxide, antimony oxide-tin oxide, or the like can be suitably used. However, when the inorganic oxide fine particles are simply mixed and dispersed with the hard coat resin, the crosslinking density of the hard coat resin itself tends to decrease, and the hardness tends to decrease. Therefore, it is more preferable that the surface of the inorganic oxide particles is treated with an acryloxy-functional silane or the like and modified with acrylate so as to be crosslinked by ionizing radiation, and then mixed with the hard coat resin. When the surface acrylated inorganic oxide fine particles use an acrylic monomer or a prepolymer for the hard coat resin, they participate in crosslinking with the hard coat resin, so that even when blended in large amounts, the hardness does not decrease, Conversely, the hardness tends to increase. Further, it is easily mixed with the hard coat resin, and is excellent in transparency after mixing. Inorganic oxide fine particles subjected to acrylate surface treatment may be used in combination with fine particles not subjected to acrylate surface treatment.

The addition amount of the fine particles is in the range of 0.001 to 90% by weight, preferably 0.2 to 40% by weight. still,
The hard coat layer referred to in the present invention has a pencil hardness of H or more. As a method for forming the hard coat layer using the ionizing radiation paint, a usual coating method, for example, bar, blade, spin, gravure, spray or the like can be used. As the transparent conductive layer in the present invention, a coating layer mainly composed of an inorganic oxide formed by coating a hydrolyzate such as a metal alkoxide, or CVD, EB evaporation, ion plating, sputtering, etc. Is a layer having a refractive index (nC) of 1.8 or more and 2.4 or less and an optical thickness (ndC) of 10 nm or more and 270 nm or less, preferably 20 nm or more and 200 nm or less. , ZnO2, CdO, SnO2, and the like. In the present invention, the base film (A.) and the resin layer (B.) are provided on the base film (A.).
Alternatively, a resin layer (M.) may be used to improve the adhesive force with the hard coat layer (D.). However, as a resin for forming the resin layer (M.), a known adhesive layer may be used. The resin for improving the property is selected from the base film (A.) and the resin layer (B.) or the hard coat layer (D.) in relation to the selected constituent resin. Select as appropriate. Specific examples thereof include acrylic resins, urethane resins, polyester resins, and the like.

[0011]

EXAMPLES The present invention will be described in more detail with reference to the following examples. The transparent conductive films obtained in the respective examples were evaluated as follows. The transparent conductive film obtained in each example was processed into an upper electrode, and a glass substrate was used as a lower electrode, and an ITO film was formed as a transparent conductive layer. The model of the touch panel was created by opposing the transparent conductive layer of the upper electrode, and input was repeatedly executed to evaluate the input durability, the presence of interference, and the occurrence of Newton rings.

Example 1 On a polyester film having a thickness of 188 μm, 50 parts of a hexafunctional acrylate monomer, 31 parts of a bifunctional urethane acrylate, 3 parts of a photoinitiator, 16 parts of colloidal silica fine particles having an average particle diameter of 10 nm, and 100 parts of toluene 2. The thickness after curing of the hard coat resin binder portion is changed to 3.
The solution was applied with a Mayer bar so as to have a thickness of 5 μm, dried with a solvent, and irradiated with ultraviolet rays at 300 mJ / cm ² using a high-pressure mercury lamp to cure the resin layer to form a resin layer (the pencil hardness of the resin layer was 2).
H). On the resin layer (hard coat layer), an ITO film was formed as a transparent conductive layer by using indium: tin = 90: 10.
The pressure in the vacuum chamber was set to 10-3 Pa, and a mixed gas of Ar and O2 was introduced.
It was formed by DC sputtering at 1 Pa. This I
The refractive index of the TO film is 2.05 and the optical thickness nd is 60 n
m.

Example 2 50 parts of a hexafunctional acrylate monomer, 31 parts of a bifunctional urethane acrylate, 3 parts of a photoinitiator, and silica particles 3 having an average particle diameter of 5 μm on a 188 μm thick polyester film.
Parts, 6 parts of colloidal silica fine particles having an average particle diameter of 10 nm,
A coating composed of 10 parts of colloidal silica fine particles having an average particle diameter of 10 nm and 100 parts of toluene, the surface of which has been acrylated, is applied with a Mayer bar so that the thickness of the hard coat resin binder portion after curing becomes 3.5 μm. After drying, the resin layer was irradiated with ultraviolet rays at 300 mJ / cm ² by a high pressure mercury lamp and cured to form a resin layer (the pencil hardness of the resin layer was 2H). On the resin layer (hard coat layer),
An ITO film was used as a transparent conductive layer, and indium: tin = 90:
10-3 Pa in the vacuum chamber using 10 targets
5 × 10 5 while introducing a mixed gas of Ar and O 2.
−1 Pa was formed by DC sputtering. The refractive index of this ITO film is 2.05 and the optical thickness nd is 60
nm.

Comparative Example 1 90 parts of a polyester polyol resin and an isocyanate curing agent 10 were coated on a 188 μm thick polyester film.
Parts, 50 parts of MEK and 50 parts of toluene are applied with a Meyer bar so that the cured thickness of the binder part becomes 3.5 μm, dried at 120 ° C. for 60 seconds, cured and cured to form a resin layer (pencil hardness: B). On the resin layer, an ITO film as a transparent conductive layer was formed by using indium:
Using a target of tin = 90: 10, the inside of the vacuum chamber was 10
-3 Pa, and 5 × 10 -1 Pa while introducing a mixed gas of Ar and O 2, and formed by DC sputtering. The refractive index of this ITO film was 2.05, and the optical thickness nd was 60 nm.

Comparative Example 2 90 parts of a polyester polyol resin and an isocyanate curing agent 10 were coated on a 188 μm thick polyester film.
Parts, 50 parts of MEK, 50 parts of toluene, and 3 parts of silica particles having an average particle diameter of 5 μm are applied with a Mayer bar so that the cured thickness of the binder part becomes 3.5 μm, and dried at 120 ° C. for 60 seconds. And cured to form a resin layer (pencil hardness was B). On the resin layer, an ITO film was used as a transparent conductive layer, a target of indium: tin = 90: 10 was used, the vacuum chamber was set to 10-3 Pa, and A
5 × 10-1 P while introducing a mixed gas of r and O2
a was formed by DC sputtering. The refractive index of this ITO film was 2.05, and the optical thickness nd was 60 nm.

The transparent conductive films obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated as follows. (1) Input durability An input test was performed using a polyacetal pen until the surface resistance changed by 5%. (2) Interference A touch panel model was placed on a TFT liquid crystal color display having a pitch of RGB 360 μm, and the degree of interference was visually evaluated. A: No interference B: Strong interference (3) Newton ring Pen input was performed, and the occurrence of Newton rings was evaluated visually. A: Without Newton ring B: With Newton ring “Evaluation result” Input durability Interference Newton ring Example 1 50,000 times A B Example 2 50,000 times A A Comparative example 1 2000 times AB Comparative example 2 2000 times B A

[0017]

The transparent conductive film of the present invention has excellent input durability when used for a touch panel or the like, prevents interference on a display, and prevents sticking or Newton's ring from occurring. It is a film.

Claims (5)

[Claims] 1. A resin layer (B.) containing at least a resin and fine particles having an average particle size of 1 to 500 nm is formed on at least one surface of a transparent substrate film (A.) directly or via another layer, A transparent conductive film comprising a transparent conductive layer (C.) provided directly or via another layer on the resin layer (B.). 2. The transparent conductive film according to claim 1, wherein the resin layer (B.) is a hard coat layer. 3. The resin layer (B.) has an average particle size of 0.6 to 20.
2. The transparent conductive film according to claim 1, further comprising particles of μm. 4. The particles are 0.05 to 30% by weight based on the resin content, and the fine particles are 0.001 to 90% by weight based on the resin content.
Resin layer B. The transparent conductive film according to claim 1, which is: 5. The transparent conductive film according to claim 1, wherein a hard coat layer (D.) is formed on the side of the base film (A.) opposite to the side where the transparent conductive layer (C.) is provided.