Transparent Conductive Film

Abstract

To provide a transparent conductive film which is excellent in pen slide durability, pen weight pressurization durability, and antiglare property, when being used in a touch panel.SOLUTION: There is provided a transparent conductive film, wherein a crystal particle size of a transparent conductive film of an indium-tin complex oxide is 10 to 100 nm, a degree of crystallization of the transparent conductive film of the indium-tin complex oxide is 20 to 80%, the transparent conductive film of the indium-tin complex oxide contains 0.5 to 10 mass% of tin oxide, thickness of the transparent conductive film of the indium-tin complex oxide is 10 to 30 nm, when three-dimensional surface roughness SRa of the transparent conductive film of the indium-tin complex oxide is represented by X, X is 1 to 100 nm, and when three-dimensional surface roughness SRa on a surface opposite to the side of the transparent conductive film on a transparent plastic film base material is represented by Y, Y is 70 to 270 nm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a transparent conductive film in which a transparent conductive film of crystalline indium-tin composite oxide is laminated on a transparent plastic film substrate, and in particular to a transparent conductive film that has excellent pen sliding durability, pen heavy pressure durability, and anti-glare properties when used in a resistive touch panel. [Background technology]

[0002] Transparent conductive films, which are made by laminating a transparent, low-resistance thin film onto a transparent plastic substrate, are widely used in electrical and electronic applications that utilize their conductivity, such as flat panel displays such as liquid crystal displays and electroluminescence (EL) displays, and transparent electrodes in touch panels.

[0003] Resistive touch panels combine a fixed electrode (a glass or plastic substrate coated with a transparent conductive thin film) with a movable electrode (film electrode) (a plastic film coated with a transparent conductive thin film), which is layered on top of a display. The touch panel recognizes position information by pressing the film electrode with a finger or pen, bringing the transparent conductive thin films of the fixed electrode and film electrode into contact. Compared to a finger, a pen often exerts a stronger force on the touch panel. Continuous pen input on a touch panel can cause damage such as cracking, peeling, and wear to the transparent conductive thin film on the film electrode side. Furthermore, applying force greater than that expected for normal use, such as hitting the touch panel hard with a pen or using very strong pen input, can cause damage such as cracking and peeling to the transparent conductive thin film. To address these issues, transparent conductive films that combine excellent pen sliding durability and high pen pressure durability are needed. Furthermore, anti-glare properties are also required to prevent glare from fluorescent lights and other light sources from appearing on the touch panel.

[0004] One method for improving pen sliding durability is to make the transparent conductive thin film on the film electrode side crystalline (see, for example, Patent Document 1). However, conventional transparent conductive films have been realized with excellent pen sliding durability by controlling the crystallinity of indium-tin composite oxide. However, conventional transparent conductive films were insufficient when subjected to the pen heavy pressure durability test described below. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-071171 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the above-mentioned conventional problems, an object of the present invention is to provide a transparent conductive film that has excellent pen sliding durability when used in a touch panel, excellent pen heavy pressure durability, and can also provide excellent anti-glare properties. [Means for solving the problem]

[0007] The present invention has been made in view of the above circumstances, and the transparent conductive film of the present invention, which has been able to solve the above problems, has the following configuration. 1. A transparent conductive film in which a transparent conductive film of indium-tin composite oxide is laminated on one side of a transparent plastic film substrate, wherein the ON resistance of the transparent conductive film in the pen sliding durability test described below is 10 kΩ or less, and further, the increase in the surface resistance of the transparent conductive film in the pen heavy pressure test described below is 1.5 or less, and further, the 60° specular gloss of the side of the transparent plastic film substrate opposite the transparent conductive film side is 50% or more and 120% or less. (Pen sliding durability test method) The transparent conductive film of the present invention is used as one panel, and the other panel is a transparent conductive thin film made of a 20 nm-thick indium-tin composite oxide thin film (tin oxide content: 10% by mass) sputtered onto a glass substrate. The two panels are arranged with the transparent conductive thin films facing each other, with 30 μm diameter epoxy beads in between, and the film-side panel and the glass-side panel are attached with 170 μm thick double-sided tape to produce a touch panel. Next, a polyacetal pen (tip shape: 0.8 mmR) is used to apply a load of 2.5 N to the touch panel, and a linear sliding test of 180,000 strokes is performed. In this test, the pen load is applied to the transparent conductive film surface of the present invention. The sliding distance is 30 mm and the sliding speed is 180 mm / sec. After this sliding durability test, the ON resistance (the resistance value when the movable electrode (film electrode) and fixed electrode come into contact) is measured when the sliding part is pressed with a pen load of 0.8 N. (Pen pressure test method) A 50 mm x 50 mm piece of the transparent conductive film of the present invention was used as one panel, and the other panel consisted of a 20 nm-thick transparent conductive thin film of an indium-tin composite oxide thin film (tin oxide content: 10% by mass) sputtered onto a glass substrate. The two panels were arranged with the transparent conductive thin films facing each other, with 30 μm diameter epoxy beads sandwiched between them. The film-side panel and the glass-side panel were attached with double-sided tape adjusted to a thickness of 120 μm to produce a touch panel. A polyacetal pen (tip shape: 0.8 mm R) was used to apply a 35 N load to a position 2.0 mm from the end of the double-sided tape, and linear sliding was performed 10 times (five round trips) parallel to the double-sided tape. In this test, the pen load was applied to the surface of the transparent conductive film of the present invention. The sliding distance was 30 mm, and the sliding speed was 20 mm / sec. The sliding was performed in a position where there were no epoxy beads. After sliding, the transparent conductive film is removed and the surface resistance (four-terminal method) is measured at any five points on the sliding area, and the average value is calculated. When measuring the surface resistance, four terminals are arranged perpendicular to the sliding area, with the sliding area located between the second and third terminals. The average surface resistance value of the sliding area is divided by the surface resistance value of the non-sliding area (measured using the four-terminal method) to calculate the rate of increase in surface resistance. 2. The transparent conductive film according to claim 1, wherein the crystal grain size of the transparent conductive film of indium-tin composite oxide is 10 to 100 nm, the degree of crystallinity of the transparent conductive film of indium-tin composite oxide is 20 to 80%, the transparent conductive film of indium-tin composite oxide contains 0.5 to 10 mass % of tin oxide, the thickness of the transparent conductive film of indium-tin composite oxide is 10 to 30 nm, and when the three-dimensional surface roughness SRa of the transparent conductive film of indium-tin composite oxide is X, X is 1 to 100 nm, and further when the three-dimensional surface roughness SRa of the surface of the transparent plastic film substrate opposite to the transparent conductive film side is Y, Y is 70 to 270 nm. 3. A transparent conductive film according to claim 1 or 2 above, in which the transparent conductive film does not peel off when an adhesion test (JIS K5600-5-6:1999) is conducted on the surface of the transparent conductive film, and in which a bending resistance test (JIS K5600-5-1:1999) is conducted on the indium-tin composite oxide transparent conductive film side of the transparent conductive film, and the mandrel diameter at which cracks or peeling occurs when the bent portion is observed with a 10x magnifying glass is smaller than 20 mm. 4. The transparent conductive film according to any one of the above items 1 to 3, wherein the transparent conductive film has a thickness of 100 to 250 μm. 5. The transparent conductive film according to any one of the above items 1 to 4, which has a curable resin layer between a transparent conductive film of indium-tin composite oxide and a transparent plastic film substrate. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a transparent conductive film that has excellent pen sliding durability, excellent pen heavy pressure durability, and also excellent anti-glare properties. The obtained transparent conductive film is extremely useful for applications such as resistive touch panels. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing an example (part 1) of the longest part of a crystal grain in the present invention. [Figure 2] FIG. 3 is a schematic diagram showing another example (part 2) of the longest part of a crystal grain in the present invention. [Figure 3] FIG. 4 is a schematic diagram showing another example (part 3) of the longest part of a crystal grain in the present invention. [Figure 4] FIG. 4 is a schematic diagram showing another example (No. 4) of the longest part of a crystal grain in the present invention. [Figure 5] FIG. 2 is a schematic diagram illustrating the position of a center roll in an example of a sputtering device preferably used in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The transparent conductive film of the present invention is a transparent conductive film having a transparent conductive film of indium-tin composite oxide laminated on one side of a transparent plastic film substrate, and it is preferred that the transparent conductive film of the transparent conductive film has an ON resistance of 10 kΩ or less in the pen sliding durability test described below, an increase in the surface resistance of the transparent conductive film of the transparent conductive film in the pen heavy pressure test described below of 1.5 or less, and a 60° specular gloss of 50% or more and 120% or less on the side of the transparent plastic film substrate opposite the transparent conductive film side. (Pen sliding durability test) The transparent conductive film according to the present invention was used as one panel, and the other panel was a transparent conductive thin film consisting of a 20 nm-thick indium-tin composite oxide thin film (tin oxide content: 10% by mass) sputtered onto a glass substrate. These two panels were arranged with their transparent conductive thin films facing each other, with 30 μm diameter epoxy beads sandwiched between them. The film-side panel and the glass-side panel were attached with 170 μm-thick double-sided tape to produce a touch panel. Next, a linear sliding test was performed on the touch panel, with a 2.5 N load applied to a polyacetal pen (tip shape: 0.8 mmR) and 180,000 reciprocations. In this test, the pen load was applied to the transparent conductive film surface according to the present invention. The sliding distance was 30 mm, and the sliding speed was 180 mm / sec. After this sliding durability test, the ON resistance (the resistance value when the movable electrode (film electrode) and the fixed electrode contact each other) was measured when the sliding portion was pressed with a pen load of 0.8 N. (Pen pressure test) A transparent conductive film according to the present invention, cut to a size of 50 mm x 50 mm, was used as one panel plate. The other panel plate was a transparent conductive thin film consisting of a 20 nm-thick indium-tin composite oxide thin film (tin oxide content: 10% by mass) sputtered onto a glass substrate. These two panels were arranged with the transparent conductive thin films facing each other, with 30 μm diameter epoxy beads sandwiched between them. The film-side panel plate and the glass-side panel plate were attached with double-sided tape adjusted to a thickness of 120 μm to produce a touch panel. A polyacetal pen (tip shape: 0.8 mm R) was used to apply a 35 N load to a position 2.0 mm from the end of the double-sided tape, and linear sliding was performed 10 times (five round trips) parallel to the double-sided tape. In this test, the pen load was applied to the surface of the transparent conductive film according to the present invention. The sliding distance was 30 mm, and the sliding speed was 20 mm / sec. However, the sliding was performed in a position where there were no epoxy beads. After sliding, the transparent conductive film is removed and the surface resistance (four-terminal method) is measured at any five points on the sliding area, and the average value is calculated. When measuring the surface resistance, four terminals are arranged perpendicular to the sliding area, with the sliding area located between the second and third terminals. The average surface resistance value of the sliding area is divided by the surface resistance value of the non-sliding area (measured using the four-terminal method) to calculate the rate of increase in surface resistance.

[0011] The transparent conductive film of the present invention has excellent pen sliding durability and pen heavy pressure durability. Pen sliding durability and pen heavy pressure durability are contradictory properties. First, pen sliding durability will be described. Transparent conductive films of indium-tin composite oxide that have excellent pen sliding durability have a high degree of crystallinity in the transparent conductive film and a large crystal grain size. Crystallinity and crystal grain size will be described. Portions with circular or polygonal regions observed under a transmission electron microscope are defined as crystals (=crystal grains) of the transparent conductive film, and the remaining portions are defined as amorphous. A high degree of crystallinity indicates a high proportion of crystals. A large crystal grain size indicates large circular or polygonal regions observed under a transmission electron microscope. A transparent conductive film with a high degree of crystallinity has a high proportion of hard crystals, and a film with a large crystal grain size has large strain around the crystal grains, making the transparent conductive film hard and resulting in excellent pen sliding durability. Next, pen heavy pressure durability will be described. Transparent conductive films made of indium-tin composite oxide that exhibit excellent pen-induced heavy pressure durability require low crystallinity, small crystal grain size, and low three-dimensional surface roughness. While three-dimensional surface roughness will be discussed later, transparent conductive films with low crystallinity have a high proportion of soft amorphous material, and those with small crystal grain size have reduced strain around the crystal grains. This reduces the likelihood of cracks occurring even when a load is applied to the transparent conductive film, resulting in excellent pen-induced heavy pressure durability. As mentioned above, pen sliding durability and pen-induced heavy pressure durability are mutually exclusive properties. As a result of our research, we discovered that by controlling the crystallinity and crystal grain size of the transparent conductive film, both pen sliding durability and pen-induced heavy pressure durability can be achieved. This paper describes a transparent conductive film having a transparent conductive film that exhibits both pen sliding durability and pen-induced heavy pressure durability.

[0012] In the present invention, if the ON resistance of the transparent conductive film of the transparent conductive film in the pen sliding durability test is 10 kΩ or less, cracking, peeling, wear, etc. of the transparent conductive film is suppressed even when continuous input is made to the touch panel with a pen, which is preferable. In one embodiment, the ON resistance may be 9.5 kΩ or less, more preferably 5 kΩ or less. For example, the ON resistance may be 3 kΩ or less, 1.5 kΩ or less, and preferably 1 kΩ or less. If the ON resistance is 0 kΩ, the pen sliding durability is very excellent, and in the present invention, the ON resistance can be 0 kΩ. The ON resistance may be, for example, 3 kΩ or more, or 5 kΩ or more. By keeping the ON resistance within this range, cracks, peeling, wear, etc. on the transparent conductive film can be suppressed even when continuous input is made to the touch panel with a pen. In one embodiment, these upper and lower limits may be combined as appropriate.

[0013] In the present invention, it is desirable that the rate of increase in the surface resistance of the transparent conductive film in a pen heavy pressure test is 1.5 or less. By having such a characteristic, for example, even if a force stronger than that expected in normal use is applied, cracking, peeling, etc. of the transparent conductive film can be suppressed. More preferably, the rate of increase in the surface resistance is 1.2 or less, and particularly preferably 1.0 (no increase). Here, the rate of increase in the surface resistance of the transparent conductive film according to the present invention is preferably 1.0 or more.

[0014] In one embodiment, the ON resistance of the transparent conductive layer of the transparent conductive film in a pen sliding durability test is 0.05 kΩ or more and 9.5 kΩ or less, and the increase rate of the surface resistance value of the transparent conductive layer of the transparent conductive film in a pen heavy pressure (durability) test is 1.0 or more and 1.5 or less. As described above, pen sliding durability and pen heavy pressure durability are usually contradictory properties. In the present invention, these two durability properties can be balanced within the above ranges. Furthermore, even when continuous input is made to the touch panel with a pen, cracking, peeling, wear, etc. of the transparent conductive film can be suppressed, and further, excellent durability can be exhibited against loads due to pen sliding and heavy pen pressure. The numerical ranges and values ​​can be selected from those described in this specification.

[0015] In the present invention, excellent anti-glare properties can be provided when the 60° specular gloss of the surface opposite the transparent conductive film side on the transparent plastic film substrate is 50% or more and 120% or less. The lower the 60° specular gloss, the less reflections from fluorescent lights and the like are likely to occur, i.e., the better the anti-glare properties. More preferably, the 60° specular gloss of the surface opposite the transparent conductive film side is 100% or less. Even more preferably, the 60° specular gloss of the surface opposite the transparent conductive film side is 80% or less. A 60° specular gloss of 50% or more on the surface opposite the transparent conductive film side is preferable because it improves the clarity of images on the touch panel. The clarity of images on the touch panel was determined by the sum of the clarity of transmitted images of the transparent conductive film. The transmitted image clarity of the transparent conductive film is measured at comb widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm, and it is desirable that the total transmitted image clarity of the transparent conductive film for each comb width is 50% or more, as this will result in good image clarity on the touch panel. In this specification, the term "comb width" refers to the optical comb width conforming to JIS-K7105.

[0016] In the transparent conductive film of the present invention, the crystal grain size of the transparent conductive film of indium-tin composite oxide is preferably 10 to 100 nm, and the crystallinity of the transparent conductive film of indium-tin composite oxide is preferably 20 to 80%. When the crystal grain size of the transparent conductive film of indium-tin composite oxide is 10 nm or more, the transparent conductive film becomes appropriately hard due to strain around the crystal grains of the transparent conductive film, which is preferable because it has excellent pen sliding durability. More preferably, the crystal grain size of the transparent conductive film of indium-tin composite oxide is 30 nm or more. On the other hand, if the crystal grain size of the transparent conductive film of indium-tin composite oxide is 100 nm or less, the transparent conductive film is not too hard due to distortion around the crystal grains of the transparent conductive film, and therefore has excellent pen heavy pressure durability, which is preferable. More preferably, the crystal grain size of the transparent conductive film of indium-tin composite oxide is 90 nm or less. In one embodiment, the crystal grain size of the transparent conductive film of indium-tin composite oxide is 30 nm or more and 95 nm or less, for example, 40 nm or more and 90 nm or less. A crystallinity of 20% or more for the transparent conductive film of indium-tin composite oxide is preferred because the hard crystals contained in the transparent conductive film make it moderately hard and provide excellent pen sliding durability. A crystallinity of 25% or more for the transparent conductive film of indium-tin composite oxide is more preferred. On the other hand, a crystallinity of 80% or less for the transparent conductive film of indium-tin composite oxide is preferred because, although the amount of hard crystals contained is large, the transparent conductive film is not too hard and provides excellent pen heavy pressure durability. In one embodiment, the crystallinity of the transparent conductive film of indium-tin composite oxide is 25% or more and 78% or less, for example, 25% or more and 76% or less.

[0017] In the transparent conductive film of the present invention, when the three-dimensional surface roughness SRa of the transparent conductive film is X, X is preferably 1 to 100 nm. If X is 1 to 100 nm, the surface protrusions of the transparent conductive film are small, so that the amount of deformation of the surface protrusions when subjected to a pen pressure test is small, thereby suppressing the occurrence of cracks in the transparent conductive film, and further, since the transparent conductive film has some surface protrusions, the film can be easily wound. X is more preferably 1 to 80 nm. Even more preferably, X is 1 to 65 nm.

[0018] The transparent conductive film of the present invention is made of indium-tin composite oxide and preferably contains 0.5% to 10% by mass of tin oxide. Tin oxide in indium-tin composite oxide corresponds to an impurity in indium oxide. The presence of tin oxide impurities increases the melting point of the indium-tin composite oxide. The presence of tin oxide impurities inhibits crystallization, making it an important factor closely correlated with crystallinity, such as crystal grain size and degree of crystallinity. A tin oxide content of 0.5% by mass or more is preferred, as it ensures that the surface resistance of the transparent conductive film reaches a practical level. A tin oxide content of 1% by mass or more is more preferred, with 2% by mass or more being particularly preferred. A tin oxide content of 10% by mass or less facilitates crystallization during adjustment to the semi-crystalline state described below, and is therefore preferred for improved pen sliding durability. A tin oxide content of 8% by mass or less is more preferred, with 6% by mass or less being even more preferred, and 4% by mass or less being particularly preferred. The surface resistance of the transparent conductive film of the present invention is preferably 50 to 900 Ω / □, and more preferably 50 to 600 Ω / □.

[0019] In the present invention, the thickness of the transparent conductive film is preferably 10 nm or more and 30 nm or less. The thickness of the transparent conductive film is an important factor that is strongly correlated with crystallinity, such as crystal grain size and crystallinity. When the thickness of the transparent conductive film is 10 nm or more, the transparent conductive film does not contain too much amorphous material, and it is easy to impart an appropriate crystal grain size and crystallinity to achieve the semi-crystalline state described below, which is preferable because pen sliding durability is maintained. The thickness of the transparent conductive film is more preferably 13 nm or more, and more preferably 16 nm or more. Furthermore, when the thickness of the transparent conductive film is 30 nm or less, the crystal grain size of the transparent conductive film is not too large and the crystallinity is not too high, making it easy to maintain the semi-crystalline state and pen heavy pressure durability is preferable. The thickness is more preferably 28 nm or less, and even more preferably 25 nm or less.

[0020] In the transparent conductive film of the present invention, when the three-dimensional surface roughness SRa of the surface opposite to the transparent conductive film side on the transparent plastic film substrate is defined as Y, it is desirable that Y is 70 to 270 nm, since excellent anti-glare properties can be provided. The larger the value of Y, the better the anti-glare properties. More preferably, Y is 90 nm or more. Even more preferably, Y is 130 nm or more. Furthermore, it is preferable that the value of Y is 270 nm or less, since this improves the clarity of images on touch panels.

[0021] The transparent conductive film of the present invention preferably does not peel off even when an adhesion test (JIS K5600-5-6:1999) is conducted on the transparent conductive film surface. A transparent conductive film that does not peel off in an adhesion test is preferred because the transparent conductive film is in close contact with the layer in contact with the transparent conductive film, such as the transparent plastic substrate or the cured resin layer, and therefore cracking, peeling, abrasion, etc. of the transparent conductive film is suppressed even when continuous input is made to the touch panel with a pen, and further, cracking, peeling, etc. of the transparent conductive film is suppressed even when a force stronger than that expected in normal use is applied.

[0022] The transparent conductive film of the present invention preferably has a mandrel diameter of less than 20 mm at which cracking or peeling occurs when the bent portion is observed with a 10x magnifying glass in a bending resistance test (JIS K5600-5-1:1999) on the transparent conductive film side of the transparent conductive film. A mandrel diameter of less than 20 mm is preferred because a pen pressure test prevents cracking of the layer in contact with the transparent conductive film and cracks from occurring in the transparent conductive film. A more preferred diameter is 18 mm or less. In one embodiment, the value in the flex resistance test may be 1 mm or more, for example, 8 mm or more, 10 mm or more, and in another embodiment, the value in the flex resistance test may be 13 mm or more, or 15 mm or more. When the thickness is within this range, the layer in contact with the transparent conductive film does not crack when subjected to a pen heavy pressure test, and cracks do not occur in the transparent conductive film, which is preferable. It is also possible to provide a transparent conductive film that has both excellent pen sliding durability and excellent pen heavy pressure durability.

[0023] In the transparent conductive film of the present invention, the thickness of the transparent plastic film substrate is preferably in the range of 100 to 250 μm, more preferably 130 to 220 μm. A plastic film thickness of 100 μm or more is preferred because it maintains mechanical strength, reduces deformation due to pen input, and provides excellent pen sliding durability and pen heavy pressure durability when used in a touch panel. On the other hand, a thickness of 250 μm or less is preferred because, when used in a touch panel, it is not necessary to apply a particularly large load to position the film during pen input.

[0024] The transparent conductive film of the present invention preferably has a curable resin layer between the transparent conductive film and the plastic film substrate. The presence of the curable resin layer increases the adhesive strength of the transparent conductive film and can distribute the force applied to the transparent conductive film, thereby suppressing cracking, peeling, abrasion, etc. of the transparent conductive film in a pen sliding test and further suppressing cracking, peeling, etc. of the transparent conductive film in a pen heavy pressure test, which is preferable.

[0025] The crystallinity of the transparent conductive film of the present invention is neither too high nor too low (such crystallinity is referred to as semi-crystalline or semi-crystalline). It is extremely difficult to stably make a transparent conductive film semi-crystalline. This is because semi-crystalline is a state in which the film undergoes a sudden phase change from amorphous to crystalline and is stopped midway through. Therefore, the film is sensitive to the moisture content in the film-forming atmosphere, which is a parameter related to crystallinity, and is particularly sensitive to hydrogen-containing gases. Even a small amount of hydrogen-containing gas or moisture in the film-forming atmosphere results in almost complete crystallinity (high crystallinity). Conversely, even a small amount of hydrogen-containing gas or moisture in the film-forming atmosphere results in amorphousness (low crystallinity).

[0026] The manufacturing method for obtaining the transparent conductive film of the present invention is not particularly limited, but the following manufacturing method can be exemplified as a preferred example. Sputtering is a preferred method for forming a transparent conductive film of crystalline indium-tin composite oxide on at least one surface of a transparent plastic film substrate. To produce transparent conductive films with high productivity, a so-called roll-type sputtering device is preferably used, which supplies a film roll and winds it up into a film roll after film formation. A preferred method is to introduce a hydrogen atom-containing gas (hydrogen, ammonia, a hydrogen + argon mixed gas, or any gas containing hydrogen atoms, excluding water) into the film formation atmosphere using a mass flow controller in the amount described below. Furthermore, the film temperature during sputtering is kept below 0°C. A sintered target of indium-tin composite oxide containing 0.5 to 10 mass% tin oxide is used, and the thickness of the transparent conductive film of indium-tin composite oxide is adjusted to 10 to 30 nm. This transparent conductive film is then formed on a transparent plastic film having a three-dimensional surface roughness SRa of 1 to 100 nm. In the film-forming atmosphere during sputtering, a hydrogen atom-containing gas has the effect of inhibiting crystallization of the transparent conductive film. When hydrogen gas is flowed in the film-forming atmosphere, the value of (hydrogen gas flow rate) ÷ (inert gas flow rate + hydrogen gas flow rate) × 100 (sometimes simply referred to as hydrogen concentration) is preferably 0.01 to 3.00%. The hydrogen concentration may be, for example, 0.01% to 2.00%, or 0.01% to 1.00%. A hydrogen concentration within this range can contribute to obtaining good results in both the ON resistance value in a pen sliding durability test and the heavy pen pressure durability test, for example. Examples of inert gases include helium, neon, argon, krypton, and xenon. When using a hydrogen-atom-containing gas other than hydrogen gas, the amount of hydrogen gas (= hydrogen molecules) can be calculated by converting the amount of hydrogen atoms contained in the hydrogen-atom-containing gas. When precisely flowing the hydrogen-atom-containing gas into the film-forming atmosphere using a mass flow controller, positioning the gas outlet so that the hydrogen-atom-containing gas can be uniformly sprayed in a direction perpendicular to the longitudinal direction of the film roll reduces the likelihood of a transparent conductive film having a mixture of high and low crystallinity, making it easier to obtain a uniform semi-crystalline transparent conductive film. This makes it possible to obtain a transparent conductive film with excellent pen sliding durability and pen heavy pressure durability. Since a high water content in the film-forming atmosphere is known to reduce the crystallinity of transparent conductive films, the amount of moisture in the film-forming atmosphere is also an important factor. When using a hydrogen-atom-containing gas, the median value (the midpoint between the maximum and minimum values) of the ratio of water pressure to inert gas pressure in the film-forming atmosphere during sputtering on the film roll must be 1.0 × 10. -4 ~2.0×10 -3 Furthermore, the difference between the maximum and minimum values ​​of the ratio of water pressure to inert gas pressure in the film formation atmosphere during sputtering from the start to the end of film formation was 1.0 × 10 -3If the ratio is less than this, the uniformity of the crystallinity of the transparent conductive film is maintained throughout the entire length of the film. Therefore, in addition to using a rotary pump, turbomolecular pump, or cryopump commonly used as an exhaust device for a sputtering machine, it is preferable to reduce the amount of moisture released from the film during deposition and release a uniform amount of moisture throughout the entire length of the film by, for example, using the bombardment process described below and limiting the height difference of the unevenness on the edge surface of the film roll described below, thereby eliminating the need for precise control of the moisture content. However, the median value of the ratio of water pressure to inert gas also depends somewhat on the tin oxide content in the indium-tin composite oxide transparent conductive film and the thickness of the transparent conductive film. When the indium-tin composite oxide transparent conductive film contains a large amount of tin oxide or the transparent conductive film is thin, it is desirable to set the median value of the ratio of water pressure to inert gas lower within the above range. Conversely, when the indium-tin composite oxide transparent conductive film contains a low tin oxide content or the transparent conductive film is thick, it is desirable to set the median value of the ratio of water pressure to inert gas higher within the above range. It is preferable to deposit a transparent conductive film on a transparent plastic film by maintaining the film temperature at 0°C or below during sputtering. The film temperature during deposition is substituted by the temperature setting of a temperature controller that adjusts the temperature of the center roll that the running film contacts. Figure 5 shows a schematic diagram of an example of a sputtering device suitable for use in the present invention, in which the running film 1 partially contacts the surface of the center roll 2. An indium-tin sputtering target 4 is installed via a chimney 3, and a thin film of indium-tin composite oxide is deposited and laminated on the surface of the film 1 running on the center roll 2. The temperature of the center roll 2 is controlled by a temperature controller (not shown). A film temperature of 0°C or below is preferable because it suppresses the release of impurity gases such as water and organic gases from the film, which can cause variations in the crystallinity of the transparent conductive film, and therefore facilitates uniform crystallinity of the transparent conductive film from the start to the end of deposition. When using a hydrogen atom-containing gas, the median value (the midpoint between the maximum and minimum values) of the ratio of water pressure to inert gas in the film-deposition atmosphere during sputtering should be 1.0 x 10 -4 ~2.0×10 -3It is desirable that the ratio of water pressure to inert gas in the film-forming atmosphere during sputtering be within the above range, because the hydrogen atom-containing gas effectively inhibits the crystallinity of the transparent conductive film. It is also desirable to add oxygen gas during sputtering in order to achieve a practical level of surface resistance and total light transmittance of the transparent conductive film. This manufacturing method focuses on controlling the crystallinity with a hydrogen-containing gas, while minimizing the influence of water crystallinity, which is a factor that causes variations in the crystallinity of the transparent conductive film.

[0027] To control the moisture content when depositing an indium-tin composite oxide film on a plastic film, it is preferable to actually observe the moisture content during film deposition rather than observing the ultimate vacuum for the following two reasons.

[0028] The first reason is that when a film is formed on a plastic film by sputtering, the film is heated and moisture is released from the film, increasing the amount of moisture in the film formation atmosphere and exceeding the amount of moisture measured when the ultimate vacuum is measured. Therefore, it is more accurate to express this in terms of the amount of moisture at the time of film formation rather than in terms of the ultimate vacuum.

[0029] The second reason is the case with equipment that inputs a large amount of transparent plastic film. In such equipment, the film is input in the form of a film roll. When the film is rolled and input into a vacuum chamber, water easily escapes from the outer layer of the roll, but water does not easily escape from the inner layer of the roll. This is because, while the film roll is stopped when measuring the ultimate vacuum, the film roll runs during film formation, and the inner layer of the film roll, which contains a lot of water, is unwound, increasing the amount of moisture in the film formation atmosphere and exceeding the amount of moisture measured at the ultimate vacuum. In the present invention, the amount of moisture in the film formation atmosphere can be controlled by observing the ratio of water pressure to inert gas pressure in the film formation atmosphere during sputtering.

[0030] Before depositing the transparent conductive film, it is desirable to subject the film to a bombardment process. This process involves applying a voltage to generate a discharge and generate plasma while flowing an inert gas, such as argon, or a mixture of a reactive gas, such as oxygen, and an inert gas. Specifically, the film is preferably bombarded by RF sputtering using a stainless steel target. The bombardment process exposes the film to plasma, releasing water and organic components from the film. This reduces the amount of water and organic components released during the deposition of the transparent conductive film, which is desirable because it facilitates uniform crystallinity of the transparent conductive film from the start to the end of deposition. Furthermore, the bombardment process activates the layers in contact with the transparent conductive film, improving the adhesion of the transparent conductive film and improving pen sliding durability and pen pressure durability.

[0031] In a film roll for forming a transparent conductive film, the height difference between the most convex and most concave points on the roll end face is preferably 10 mm or less. If it is 10 mm or less, there is less unevenness in the release of water and organic components from the film end face when the film roll is placed in a sputtering device, which is preferable because it makes it easier to uniformize the crystallinity of the transparent conductive film from the start to the end of film formation.

[0032] In a method for forming a transparent conductive film of crystalline indium-tin composite oxide on at least one surface of a transparent plastic film substrate, it is desirable to introduce oxygen gas during sputtering. Introducing oxygen gas during sputtering prevents defects due to oxygen deficiency in the transparent conductive film of indium-tin composite oxide, and the transparent conductive film has low surface resistance and high total light transmittance, which is preferable. Therefore, it is desirable to introduce oxygen gas during sputtering in order to achieve a practical level of surface resistance and total light transmittance of the transparent conductive film. The total light transmittance of the transparent conductive film of the present invention is preferably 70 to 95%.

[0033] The transparent conductive film of the present invention is preferably obtained by forming a transparent conductive film of indium-tin composite oxide on a transparent plastic film substrate and then heat-treating the film in an oxygen-containing atmosphere at 80 to 200°C for 0.1 to 12 hours. A temperature of 80°C or higher facilitates a treatment to slightly increase the crystallinity to achieve a semi-crystalline state, which is preferable because it improves pen sliding durability. A temperature of 200°C or lower is preferable because it ensures the flatness of the transparent plastic film.

[0034] <Transparent plastic film substrate> The transparent plastic film substrate used in the present invention is a film obtained by melt-extruding or solution-extruding an organic polymer into a film shape, and then, as necessary, stretching the film in the longitudinal direction and / or the width direction, cooling, and heat-setting. Examples of the organic polymer include polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthalate, polypropylene terephthalate, polybutylene terephthalate, nylon 6, nylon 4, nylon 66, nylon 12, polyimide, polyamideimide, polyethersulfane, polyetheretherketone, polycarbonate, polyarylate, cellulose propionate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyetherimide, polyphenylene sulfide, polyphenylene oxide, polystyrene, syndiotactic polystyrene, and norbornene-based polymers.

[0035] Among these organic polymers, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, syndiotactic polystyrene, norbornene-based polymers, polycarbonate, polyarylate, etc. These organic polymers may be copolymerized with a small amount of monomers of other organic polymers or may be blended with other organic polymers.

[0036] The transparent plastic film substrate used in the present invention may be subjected to a surface activation treatment such as corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, or ozone treatment, as long as the object of the present invention is not impaired.

[0037] Applying a curable resin layer to a transparent plastic film substrate provides strong adhesion between the transparent conductive film and the curable resin layer and distributes the force applied to the transparent conductive film, thereby reducing cracking, peeling, and abrasion of the transparent conductive film during a pen sliding test. Furthermore, this is preferable because it also reduces cracking and peeling of the transparent conductive film during a pen-pressure test. Furthermore, forming a transparent conductive film on a curable resin layer with an irregular surface reduces the true contact area between the transparent conductive thin film and glass during a pen sliding test, improving the sliding properties between the glass surface and the transparent conductive film, improving pen sliding durability, improving film roll winding, and anti-Newton ring properties. However, excessive irregularities are undesirable because they increase the deformation of surface protrusions during a pen-pressure test, causing cracks in the transparent conductive film. Therefore, it is preferable for the surface irregularities to be 1 to 100 nm, where X is the three-dimensional surface roughness SRa of the transparent conductive film. Furthermore, the curable resin layer may be applied to both sides of the transparent plastic film substrate. When the three-dimensional surface roughness SRa of the curable resin layer on the side opposite to the side on which the transparent conductive film is formed is defined as Y, Y is preferably set to 70 to 270 nm. Details of the curable resin layer are described below.

[0038] The curable resin preferably used in the present invention is not particularly limited as long as it is a resin that is cured by application of energy such as heating, ultraviolet irradiation, or electron beam irradiation, and examples thereof include silicone resin, acrylic resin, methacrylic resin, epoxy resin, melamine resin, polyester resin, urethane resin, etc. From the viewpoint of productivity, it is preferable to use an ultraviolet curable resin as the main component.

[0039] Examples of such ultraviolet-curable resins include polyfunctional acrylate resins such as acrylic acid or methacrylic acid esters of polyhydric alcohols, and polyfunctional urethane acrylate resins synthesized from diisocyanates, polyhydric alcohols, and hydroxyalkyl esters of acrylic acid or methacrylic acid, etc. If necessary, these polyfunctional resins can be copolymerized by adding monofunctional monomers such as vinylpyrrolidone, methyl methacrylate, and styrene.

[0040] Furthermore, in order to improve the adhesive strength between the transparent conductive thin film and the curable resin layer, it is effective to treat the surface of the curable resin layer by the following methods. Specific methods include a discharge treatment method in which glow or corona discharge is applied to increase the number of carbonyl groups, carboxyl groups, and hydroxyl groups, and a chemical treatment method in which acid or alkali is used to increase the number of polar groups such as amino groups, hydroxyl groups, and carbonyl groups.

[0041] UV-curable resins are usually used with the addition of a photopolymerization initiator. Any known compound that absorbs UV light and generates radicals can be used as the photopolymerization initiator, without any particular limitations. Examples of such photopolymerization initiators include various benzoins, phenyl ketones, and benzophenones. The amount of photopolymerization initiator added is usually preferably 1 to 5 parts by mass per 100 parts by mass of the UV-curable resin.

[0042] In the present invention, the curable resin layer preferably contains inorganic particles or organic particles in addition to the curable resin, which is the main component. By dispersing inorganic particles or organic particles in the curable resin, irregularities can be formed on the surface of the curable resin, thereby improving the surface roughness over a wide area.

[0043] Examples of the inorganic particles include silica, etc. Examples of the organic particles include polyester resin, polyolefin resin, polystyrene resin, polyamide resin, etc.

[0044] In addition to inorganic particles and organic particles, it is also preferable to use a resin incompatible with the curable resin, which is the main constituent component, in combination with the curable resin. By using a small amount of a resin incompatible with the curable resin of the matrix in combination, phase separation occurs in the curable resin, allowing the incompatible resin to be dispersed in particle form. The dispersed particles of this incompatible resin form unevenness on the surface of the curable resin, thereby improving surface roughness over a wide area.

[0045] Examples of the incompatible resin include polyester resin, polyolefin resin, polystyrene resin, and polyamide resin.

[0046] Here, as an example, the blending ratio when inorganic particles are used in the curable resin layer directly below the transparent conductive film is shown. The inorganic particles are preferably 0.1 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and particularly preferably 0.1 to 12 parts by mass per 100 parts by mass of the ultraviolet curable resin. When the blending amount of the inorganic particles is 0.1 to 20 parts by mass per 100 parts by mass of the ultraviolet-curable resin, the convex portions formed on the surface of the curable resin layer are not too small, and three-dimensional surface roughness can be effectively imparted; the amount of deformation of the surface protrusions when subjected to a pen-load pressure test is small, the occurrence of cracks in the transparent conductive film is suppressed, and high-definition images can be provided; and further, since the transparent conductive film has some surface protrusions, film winding properties can be maintained, which is preferable.

[0047] Here, as an example, the blending ratio of inorganic particles in the curable resin layer on the opposite side to the side on which the transparent conductive film is formed is shown. The blending ratio is preferably 12.5 to 48 parts by mass of inorganic particles per 100 parts by mass of ultraviolet curable resin, more preferably 17 to 48 parts by mass, and particularly preferably 25.5 to 48 parts by mass. It is preferable that the amount of the inorganic particles is 12.5 to 48 parts by mass per 100 parts by mass of the ultraviolet-curable resin, because the size of the irregularities formed on the surface of the curable resin layer becomes appropriate, making it possible to provide excellent anti-glare properties.

[0048] The ultraviolet curable resin, photopolymerization initiator, and resin incompatible with inorganic particles, organic particles, and ultraviolet curable resin are dissolved in a common solvent to prepare a coating liquid. There are no particular limitations on the solvent used, and for example, alcohol-based solvents such as ethyl alcohol and isopropyl alcohol, ester-based solvents such as ethyl acetate and butyl acetate, ether-based solvents such as dibutyl ether and ethylene glycol monoethyl ether, ketone-based solvents such as methyl isobutyl ketone and cyclohexanone, and aromatic hydrocarbon-based solvents such as toluene, xylene, and solvent naphtha can be used alone or in combination.

[0049] The concentration of the resin component in the coating solution can be appropriately selected taking into consideration the viscosity and other factors appropriate for the coating method. For example, the total amount of the ultraviolet-curable resin, photopolymerization initiator, and high-molecular-weight polyester resin in the coating solution is usually 20 to 80% by mass. Furthermore, other known additives, such as a silicone-based leveling agent, may be added to the coating solution as needed.

[0050] In the present invention, the prepared coating solution is coated onto a transparent plastic film substrate. The coating method is not particularly limited, and conventional methods such as bar coating, gravure coating, and reverse coating can be used.

[0051] The coated coating liquid is then dried, where the solvent is evaporated and removed. During this process, the high-molecular-weight polyester resin that was uniformly dissolved in the coating liquid becomes particles and precipitates in the UV-curable resin. After the coating is dried, the plastic film is irradiated with UV light, causing the UV-curable resin to crosslink and harden, forming a hard-coat layer. During this hard-coat process, the high-molecular-weight polyester resin particles are fixed in the hard-coat layer, and protrusions are formed on the surface of the hard-coat resin layer, improving surface roughness over a wide area.

[0052] The thickness of the curable resin layer is preferably in the range of 0.1 to 15 μm, more preferably in the range of 0.5 to 10 μm, and particularly preferably in the range of 1 to 8 μm. When the thickness of the curable resin layer is 0.1 μm or more, sufficient protrusions are formed, which is preferable. On the other hand, when the thickness is 15 μm or less, productivity is good, which is preferable. [Example]

[0053] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Various measurements and evaluations in the examples were carried out by the following methods. (1) Total light transmittance The total light transmittance was measured using NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS-K7136-1:1997.

[0054] (2) Surface resistance Measurement was carried out by the four-terminal method in accordance with JIS-K7194:1994. The measuring instrument used was Lotesta AX MCP-T370 manufactured by Mitsubishi Chemical Analytech Co., Ltd.

[0055] (3) Three-dimensional center plane average surface roughness SRa The three-dimensional central plane average surface roughness SRa is specified in ISO 25178, and was determined using a three-dimensional surface profiler VertScan (R5500H-M100, manufactured by Ryoka Systems Co., Ltd. (measurement conditions: wave mode, measurement wavelength 560 nm, objective lens 10x)). Five measurements were taken, and the average value was calculated. Here, the values ​​were rounded to the nearest tenth in nm. Here, the three-dimensional surface roughness SRa of the transparent conductive film is defined as X, and the surface of the transparent plastic film substrate opposite the transparent conductive film side is defined as SRa. Hardening resin layer The three-dimensional surface roughness SRa is defined as Y.

[0056] (4) Crystal grain size A film sample with a laminated transparent conductive thin film layer was cut into pieces measuring 1 mm x 10 mm, and attached to the top surface of a suitable resin block with the conductive thin film facing outward. After trimming, ultrathin sections roughly parallel to the film surface were prepared using a standard ultramicrotome technique. The slice was observed under a transmission electron microscope (JEOL, JEM-2010) and a surface portion of the conductive thin film that was not significantly damaged was selected and photographed at an accelerating voltage of 200 kV and a direct magnification of 40,000 times. When observing crystal grains under a transmission electron microscope, the longest part of each crystal grain is measured, and the average of these measurements is taken as the crystal grain size. Figures 1 to 4 show an example of how to determine the longest part when measuring the longest part of a crystal grain. That is, the longest part is determined by the length of the straight line that allows the largest measurement of the grain size of each crystal grain.

[0057] (5) Thickness of the transparent conductive film (film thickness) A film sample piece laminated with a transparent conductive thin film layer was cut into 1 mm x 10 mm pieces and embedded in epoxy resin for electron microscopy. This was fixed in a sample holder of an ultramicrotome, and a thin cross-sectional section parallel to the short side of the embedded sample piece was prepared. Next, a portion of this section where the thin film was not significantly damaged was photographed using a transmission electron microscope (JEOL, JEM-2010) at an accelerating voltage of 200 kV and a bright field magnification of 10,000 times, and the film thickness was determined from the photograph obtained.

[0058] (6) Pen sliding durability test The transparent conductive film according to the present invention was used as one panel, and the other panel was a transparent conductive thin film consisting of a 20 nm-thick indium-tin composite oxide thin film (tin oxide content: 10% by mass) sputtered onto a glass substrate. These two panels were arranged with the transparent conductive thin films facing each other, with 30 μm diameter epoxy beads in between, to fabricate a touch panel. Next, a linear sliding test was performed on the touch panel, with a 5.0 N load applied to a polyacetal pen (tip shape: 0.8 mmR) and 180,000 reciprocations. In this test, the pen load was applied to the transparent conductive film surface according to the present invention. The sliding distance was 30 mm, and the sliding speed was 180 mm / sec. After this sliding durability test, the ON resistance (the resistance value when the movable electrode (film electrode) and the fixed electrode come into contact) was measured when the sliding portion was pressed with a pen load of 0.8 N. The ON resistance is preferably 10 kΩ or less. In the comparative examples, the films in the respective comparative examples were used instead of the transparent conductive film according to the present invention.

[0059] (7) Pen heavy pressure test A transparent conductive film according to the present invention, cut to a size of 50 mm x 50 mm, was used as one panel plate. The other panel plate was a transparent conductive thin film consisting of a 20 nm-thick indium-tin composite oxide thin film (tin oxide content: 10% by mass) sputtered onto a glass substrate. These two panels were arranged with the transparent conductive thin films facing each other, with 30 μm diameter epoxy beads sandwiched between them. The film-side panel plate and the glass-side panel plate were attached with double-sided tape adjusted to a thickness of 120 μm to produce a touch panel. A polyacetal pen (tip shape: 0.8 mm R) was used to apply a 35 N load to a position 2.0 mm from the end of the double-sided tape, and linear sliding was performed 10 times (five round trips) parallel to the double-sided tape. In this test, the pen load was applied to the surface of the transparent conductive film according to the present invention. The sliding distance was 30 mm, and the sliding speed was 20 mm / sec. However, the sliding was performed in a position where there were no epoxy beads. After sliding, the transparent conductive film is removed and the surface resistance (four-terminal method) is measured at any five points on the sliding area, and the average value is calculated. When measuring the surface resistance, four terminals are arranged perpendicular to the sliding area, with the sliding area located between the second and third terminals. The average surface resistance value of the sliding area is divided by the surface resistance value of the non-sliding area (measured using the four-terminal method) to calculate the rate of increase in surface resistance. In the comparative examples, the films in the respective comparative examples were used instead of the transparent conductive film according to the present invention.

[0060] (8) Measurement of the tin oxide content in transparent conductive films Cut the sample (approximately 15 cm 2 ) was placed in a quartz Erlenmeyer flask, 20 ml of 6 mol / l hydrochloric acid was added, and the flask was sealed with film to prevent the acid from volatilizing. The flask was left at room temperature for 9 days with occasional shaking to dissolve the transparent conductive film. The remaining film was removed, and the hydrochloric acid in which the transparent conductive film had dissolved was used as the measurement solution. In and Sn in the solution were determined using a calibration curve method with an ICP optical emission spectrometer (manufacturer: Rigaku, model: CIROS-120 EOP). A wavelength with high sensitivity and no interference was selected for the measurement wavelength for each element. Commercially available standard solutions of In and Sn were diluted and used as standard solutions.

[0061] (9) Adhesion test The test was carried out in accordance with JIS K5600-5-6:1999.

[0062] (10) Bending resistance test The test was carried out in accordance with JIS K5600-5-1: 1999. However, if no cracking or peeling occurred up to a mandrel diameter of 13 mm, no further bending resistance tests were carried out, and all tests were recorded as 13 mm.

[0063] (11) 60° specular gloss test The 60° specular gloss of the surface opposite to the transparent conductive film side on the transparent plastic film substrate was measured in accordance with JIS Z 8741. The measuring machine used was a Gloss Meter VG 2000 manufactured by Nippon Denshoku Industries Co., Ltd.

[0064] (12) Transmitted image clarity test In accordance with JIS-K7105, the transmitted image clarity of the transparent conductive film was measured at comb widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm, and the sum of the transmitted image clarity for each comb width was calculated. The measuring device used was an image clarity measuring instrument ICM-1T manufactured by Suga Test Instruments Co., Ltd.

[0065] The transparent plastic film substrate used in the examples and comparative examples was a biaxially oriented transparent PET film (A4340, manufactured by Toyobo Co., Ltd.; thickness is shown in Table 1) with easy-adhesion layers on both sides. For the curable resin layer, 100 parts by mass of a photopolymerization initiator-containing acrylic resin (Seikabeam® EXF-01J, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) was blended with silica particles (Snowtex ZL, manufactured by Nissan Chemical Industries, Ltd.) in the amount shown in Table 1. A toluene / MEK (8 / 2: mass ratio) mixed solvent was added as a solvent to a solids concentration of 50% by mass, and the mixture was stirred to dissolve uniformly to prepare a coating solution (hereinafter referred to as Coating Solution A). The prepared coating solution was applied using a Meyer bar to a coating thickness of 5 μm. After drying at 80°C for 1 minute, the coating was irradiated with ultraviolet light (light intensity: 300 mJ / cm) using an ultraviolet irradiation device (UB042-5AM-W, manufactured by Eye Graphics Co., Ltd.).2 The curable resin layers were formed on both sides of the transparent plastic substrate.

[0066] (Examples 1 to 8) Each example was carried out under the conditions shown in Table 1 as follows. The film is placed in the vacuum chamber and 1.5 x 10 -4 Then, after oxygen was introduced, argon was introduced as an inert gas and hydrogen gas as a hydrogen-containing gas at the concentrations shown in Table 1, and the total pressure was adjusted to 0.6 Pa. 3W / cm for an indium-tin composite oxide sintered target or an indium oxide sintered target that does not contain tin oxide 2 A transparent conductive film was formed by DC magnetron sputtering using a power density of 1000 W. The film thickness was controlled by changing the speed at which the film passed over the target. The ratio of water vapor pressure to inert gas in the film-forming atmosphere during sputtering was measured using a gas analyzer (Transpector XPR3, manufactured by Inficon). In each example, the ratio of water vapor pressure to inert gas in the film-forming atmosphere during sputtering was adjusted by adjusting the presence or absence of a bombardment process, the unevenness of the film roll end surface, and the temperature of the heating medium in the temperature regulator that controls the temperature of the center roll with which the film is in contact, as shown in Table 1. The temperature exactly midway between the maximum and minimum temperatures from the start to the end of film formation on the film roll is listed as the median value in Table 1. The film on which the transparent conductive film was formed and laminated was subjected to the heat treatment shown in Table 1, and then measurements were carried out. The measurement results are shown in Table 1.

[0067] (Comparative Examples 1 to 9) Transparent conductive films were prepared and evaluated in the same manner as in Example 1 under the conditions shown in Table 1. However, in Comparative Example 7, no curable resin layer was provided. However, in Comparative Example 8, the thickness of the coating of the curable resin layer was adjusted to 20 μm. The results are shown in Table 2.

[0068] [Table 1A]

[0069] [Table 1B]

[0070] [Table 2A]

[0071] [Table 2B]

[0072] As shown in Tables 1A and 1B, the transparent conductive films of Examples 1 to 8 are excellent in pen sliding durability, pen heavy pressure durability, and anti-glare, and combine all properties. However, as shown in Table 2, Comparative Examples 1 to 9 do not satisfy all of the pen sliding durability, pen heavy pressure durability, and anti-glare properties. [Industrial Applicability]

[0073] As described above, according to the present invention, a transparent conductive film having excellent pen sliding durability, pen heavy pressure durability, and anti-glare properties can be produced, which is extremely useful for applications such as resistive touch panels. [Explanation of symbols]

[0074] 1. Film 2. Center roll 3. Chimney 4. Indium-tin composite oxide target

Claims

[Claim 1] A transparent conductive film having a transparent conductive film of indium-tin composite oxide laminated on one surface of a transparent plastic film substrate, The transparent conductive film is made of indium-tin composite oxide and has a curable resin layer containing silica particles between the transparent plastic film substrate. a curable resin layer containing silica fine particles on the surface opposite to the surface on which the transparent conductive film is formed on the transparent plastic film substrate; the crystal grain size of the transparent conductive film of indium-tin composite oxide is 10 to 100 nm, the crystallinity of the transparent conductive film of indium-tin composite oxide is 20 to 80%, the transparent conductive film of indium-tin composite oxide contains 0.5 to 10 mass % of tin oxide, the thickness of the transparent conductive film of indium-tin composite oxide is 10 to 30 nm, and when the three-dimensional surface roughness SRa of the transparent conductive film of indium-tin composite oxide is X, X is 1 to 100 nm, and further when the three-dimensional surface roughness SRa of the curable resin layer on the surface opposite to the transparent conductive film side on the transparent plastic film substrate is Y, Y is 70 to 270 nm, The transparent conductive film has a thickness of 100 to 250 μm, A transparent conductive film in which the transparent conductive film does not peel off when an adhesion test (JIS K5600-5-6:1999) is conducted on the surface of the transparent conductive film, and in which a bending resistance test (JIS K5600-5-1:1999) is conducted on the indium-tin composite oxide transparent conductive film side of the transparent conductive film, and when the bending portion is observed with a 10x magnifying glass, cracks or peeling occurs, the mandrel diameter is smaller than 20 mm.

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