Transparent conductive film

Abstract

Provided is a transparent conductive film having a brisk operability when used for a touch panel and excellent pen-sliding durability. The transparent conductive film is a transparent conductive film in which an indium-tin composite oxide is laminated on at least one side of a transparent plastic film substrate, and the input start load of the transparent conductive film obtained by a specific input load test method is 3 g or more and 15 g or less.

Description

Technical Field

[0001] The present invention relates to a transparent conductive film having an indium-tin composite oxide laminated on a transparent plastic film substrate, and particularly to a transparent conductive film having a light operability and excellent pen-sliding durability when used in a resistive film type touch panel. Background Art

[0002] A transparent conductive film formed by laminating a transparent and low-resistance film on a transparent plastic substrate is widely used in applications that utilize its conductivity, such as flat panel displays such as liquid crystal displays and electroluminescent (EL) displays, and applications in the electrical / electronic field such as transparent electrodes of touch panels.

[0003] A resistive film type touch panel is a touch panel formed by combining a fixed electrode coated with a transparent conductive film on a glass or plastic substrate and a movable electrode (= film electrode) coated with a transparent conductive film on a plastic film, and is used by being laminated on the upper side of a display body. When a finger or a pen presses the film electrode, the transparent conductive films of the fixed electrode and the film electrode come into contact with each other, which serves as an input for position recognition of the touch panel. In particular, when inputting with a pen, pen-sliding durability is required.

[0004] In addition, in recent years, since capacitive touch panels are common, in resistive film type touch panels as well as in capacitive touch panels, it is required to be able to input even with a light touch. For example, it is strongly required to be able to input even with a light touch for people with weak finger-pressing force due to age, illness, or other reasons, or people with weak pen pressure.

[0005] However, in a resistive film type touch panel, in order to press the film electrode with a finger or a pen and make the transparent conductive films of the fixed electrode and the film electrode come into contact with each other, a certain degree of input load is required, so there is no light operation feeling like that of a capacitive touch panel. In order to solve these problems, a transparent conductive film having a light operability is desired.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-071171

[0009] The conventional transparent conductive film shown in Patent Document 1 attempts to improve pen-sliding durability by controlling the crystallinity of the indium-tin composite oxide. However, the conventional transparent conductive film has insufficient operability when the input load test described below is performed. Summary of the Invention

[0010] -Problems to be Solved by the Invention-

[0011] An object of the present invention is to provide a transparent conductive film having a light operability and excellent pen-sliding durability in view of the above-mentioned conventional problems.

[0012] -Means for Solving the Problem-

[0013] The present invention has been completed in view of the above situation, and the transparent conductive film of the present invention capable of solving the above problems has the following structure.

[0014] 1. A transparent conductive film, wherein a transparent conductive film of indium-tin composite oxide is laminated on at least one side of a transparent plastic film substrate.

[0015] The input start load of the transparent conductive film obtained by the following input load test is 3 g or more and 15 g or less.

[0016] (Input Load Test Method)

[0017] The transparent conductive film (size: 220 mm × 135 mm) is used as one panel, and as the other panel, a transparent conductive film A made of an indium-tin composite oxide film (tin oxide content: 10% by mass) is used. The indium-tin composite oxide film is formed on a glass substrate (size: 232 mm × 151 mm) by sputtering and has a thickness of 20 nm.

[0018] On the side of the glass substrate with the indium-tin composite oxide film, hereinafter also referred to as ITO glass, of the transparent conductive film A, epoxy resins (longitudinal 60 μm × transverse 60 μm × height 5 μm) as dot spacers are arranged in a square lattice pattern with a pitch of 4 mm.

[0019] Next, starting from any one of the four corners of the ITO glass, a double-sided tape (thickness: 105 μm, width 6 mm) is pasted on the side of the transparent conductive film A of the ITO glass so that a rectangle of 190 mm × 135 mm can be formed.

[0020] Next, on the double-sided tape pasted on the ITO glass, the transparent conductive film B side of the transparent conductive film is pasted, and the transparent conductive film A and the transparent conductive film B are laminated so as to face each other.

[0021] At this time, one short side of the transparent conductive film protrudes from the ITO glass.

[0022] Next, a tester is connected to the ITO glass and the transparent conductive film.

[0023] Next, a load is applied from the side of the transparent conductive film using a polyoxymethylene pen with a tip shape of 0.8 mm R, and the load value when the resistance value measured by the tester is stable is set as the input start load.

[0024] The position where the load is applied with the pen is the central area surrounded by four point spacers, and the average value of the input start loads at three points is calculated.

[0025] For example, it is preferable to measure the input start load at any three points more than 50 mm away from the double-sided tape and take the average value. In addition, the decimal point can also be rounded.

[0026] In addition, the position where the load is applied with the pen is Figure 6 the central area of the four point spacers shown. In Figure 6 it, each reference numeral represents the ITO glass 10, the point spacer 11, and the position 12 where the load is applied with the pen.

[0027] 2. According to the above-mentioned transparent conductive film, wherein,

[0028] The flexural resistance of the following film flexural resistance test is 0.23 N·cm or more and 0.90 N·cm or less, and further, the following average maximum peak height of the conductive surface of the transparent conductive film satisfies the following formulas (2-1) and (2-2).

[0029] (Film flexural resistance test method)

[0030] A test piece of 20 mm × 250 mm is collected from the transparent conductive film, and the test piece is placed on a smooth horizontal table with the transparent conductive layer facing up. At this time, only the 20 mm × 20 mm part of the test piece is placed on the horizontal table, and the 20 mm × 230 mm part is placed so as to protrude outside the horizontal table. In addition, a heavy object is placed on the 20 mm × 20 mm part of the test piece. At this time, the weight and size of the heavy object are selected so that there is no gap between the test piece and the horizontal table.

[0031] Next, the difference in height between the horizontal table and the front end of the film is read with a scale, and hereinafter it is δ. Next, the numerical value is substituted into the following formula (1) to calculate the flexural resistance.

[0032] (g × a × b × L 4 ) ÷ 8δ (N·cm) Formula (1)

[0033] g = acceleration due to gravity, a = length of the short side of the test piece, b = specific gravity of the test piece, L = length of the test piece, δ = difference in height between the horizontal table and the front end of the film

[0034] (Average maximum peak height evaluation)

[0035] The average maximum peak height is the average of the maximum peak heights at 5 points. The method for selecting the 5 points is as follows: First, arbitrarily select 1 point A. Next, select 1 point each upstream and downstream of A by 1 cm in the machine direction (MD) of the film, for a total of 2 points. Next, select 1 point each to the left and right of A by 1 cm in the transverse direction (TD) of the film, for a total of 2 points. The maximum peak height is defined by ISO 25178, and using a three-dimensional surface shape measuring device, Bert Scan (manufactured by Rhombic System Co., Ltd., R5500H-M100 (measurement conditions: wave mode, measurement wavelength 560 nm, objective lens 10 times)), the maximum peak height is obtained. In addition, values less than 1 nm are rounded off.

[0036] Average maximum peak height (μm) ≥ 4.7 × Flexural property - 1.8 Equation (2-1)

[0037] 0.005 (μm) ≤ Average maximum peak height (μm) ≤ 12.000 (μm) Equation (2-2)

[0038] 3. According to the above-mentioned transparent conductive film, wherein,

[0039] The maximum value of the maximum peak height in the evaluation of the average maximum peak height exceeds 1.0 times and is 1.4 times or less of the average maximum peak height, and,

[0040] The minimum value of the maximum peak height in the evaluation of the average maximum peak height is 0.6 times or more and 1.0 times or less of the average maximum peak height.

[0041] 4. According to the above-mentioned transparent conductive film, wherein,

[0042] The thickness of the transparent conductive film is 10 nm or more and 100 nm or less.

[0043] 5. According to the above-mentioned transparent conductive film, wherein,

[0044] The concentration of tin oxide contained in the transparent conductive film is 0.5% by mass or more and 40% by mass or less.

[0045] 6. According to the above-mentioned transparent conductive film, wherein,

[0046] There is a curable resin layer between the transparent conductive film and the transparent plastic film substrate,

[0047] On the side opposite to the transparent conductive film of the transparent plastic film substrate, there is also a functional layer.

[0048] 7. According to the above-mentioned transparent conductive film, wherein,

[0049] An easy-bonding layer is provided on at least one side of the transparent plastic film substrate.

[0050] 8. According to the above-mentioned transparent conductive film, wherein,

[0051] The easily adherable layer is disposed at least at one position between the transparent plastic film substrate and the curable resin layer, or between the transparent plastic film substrate and the functional layer.

[0052] 9. According to the above-mentioned transparent conductive film, wherein,

[0053] The on-resistance of the transparent conductive film obtained by the following pen sliding durability test is 10 kΩ or less.

[0054] (Pen sliding durability test)

[0055] Use the transparent conductive film as one panel, and as the other panel, use a transparent conductive film composed of an indium-tin composite oxide film (tin oxide content: 10% by mass), which is formed on a glass substrate by sputtering and has a thickness of 20 nm. Arrange these two panels with an epoxy bead having a diameter of 30 μm in between so that the transparent conductive films face each other to fabricate a touch panel. Next, apply a load of 2.5 N to a polyacetal pen (front end shape: 0.8 mmR), and conduct a linear sliding test with 50,000 reciprocations on the touch panel. The sliding distance at this time is 30 mm, and the sliding speed is 180 mm / second. After this sliding durability test, measure the on-resistance (the resistance value when the movable electrode (thin film electrode) contacts the fixed electrode) when pressing the sliding portion with a pen load of 0.8 N.

[0056] 10. According to the above-mentioned transparent conductive film, wherein,

[0057] In the adhesion test according to JIS K5600-5-6:1999 on the surface of the transparent conductive film, the residual area ratio of the transparent conductive film is 95% or more.

[0058] -Advantages of the invention-

[0059] According to the present invention, it is possible to provide a transparent conductive film having a light operability and excellent pen sliding durability. Description of the drawings

[0060] Figure 1 It is a schematic diagram showing the position of the center roll as an example of a sputtering device preferably used in the present invention.

[0061] Figure 2 It is a schematic diagram showing the structure of one embodiment of the present invention.

[0062] Figure 3 It is a schematic diagram showing the structure of one embodiment of the present invention.

[0063] Figure 4 It is a schematic diagram showing the structure of one embodiment of the present invention.

[0064] Figure 5 It is a schematic diagram showing the structure of one embodiment of the present invention.

[0065] Figure 6 It is a schematic diagram illustrating the measurement positions in the input load test method. Detailed Description of the Invention

[0066] 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 at least one side of a transparent plastic film substrate, and is a transparent conductive film having an input start load of 3 g or more and 15 g or less obtained by the following input load test.

[0067] (Input Load Test Method)

[0068] A transparent conductive film (size: 220 mm × 135 mm) is used as one panel, and as the other panel, a transparent conductive film A made of an indium-tin composite oxide film (tin oxide content: 10% by mass) is used. The indium-tin composite oxide film is formed on a glass substrate (size: 232 mm × 151 mm) by sputtering and has a thickness of 20 nm.

[0069] Epoxy resin (longitudinal 60 μm × transverse 60 μm × height 5 μm) as a dot spacer is arranged in a square lattice pattern with a 4 mm pitch on the side of the glass substrate with the indium-tin composite oxide film, hereinafter also referred to as ITO glass, of the transparent conductive film A.

[0070] Next, starting from any one of the four corners of the ITO glass, a double-sided tape (thickness: 105 μm, width 6 mm) is pasted on the side of the transparent conductive film A of the ITO glass so as to be able to form a rectangle of 190 mm × 135 mm.

[0071] Next, the transparent conductive film B side of the transparent conductive film is pasted on the double-sided tape pasted on the ITO glass, and the transparent conductive film A and the transparent conductive film B are stacked so as to face each other.

[0072] At this time, one short side of the transparent conductive film protrudes from the ITO glass.

[0073] Next, the ITO glass and the transparent conductive film are connected with a tester.

[0074] Next, a load is applied from the side of the transparent conductive film using a polyacetal pen (front end shape: 0.8 mmR), and the load value when the resistance value measured by the tester is stabilized is set as the input start load.

[0075] The position where the load is applied with a pen is the central area surrounded by four point spacers, and the average value of the input start load at three points is calculated.

[0076] For example, the input start load is preferably measured at any three points more than 50 mm away from the double-sided tape and the average value is obtained. In addition, rounding can also be performed on the decimal point.

[0077] In addition, as Figure 6 shown, the position where the load is applied with a pen is the central area of the four point spacers.

[0078] Here, in the present invention, in the case of measurement using a tester, according to external important factors such as the measured environment, the judgment of "stable resistance value" is preferably a state where the resistance value varies within a range of ±5%.

[0079] The present invention having such characteristics can provide a transparent conductive film having a light operability and excellent pen sliding durability. The obtained transparent conductive film is extremely useful for applications such as resistive film type touch panels.

[0080] The transparent conductive film of the present invention has a light operability. It has been found that: the maximum peak height of the surface on the transparent conductive film side of the indium-tin composite oxide transparent conductive film with excellent operability is in a moderate range relative to the height of the point spacers of the ITO glass for touch panels; the bending resistance of the film in the bending resistance test is low; the tin oxide concentration of the transparent conductive film is close to the tin oxide concentration of the ITO glass for touch panels.

[0081] The light operability will be described. The light operability means that even when pressing on the resistive film type touch panel from the transparent conductive film side with a pen or a finger with a light force, input can be made to the resistive film type touch panel. For the light operability, in the present invention, it is evaluated by an input load test. In the present invention, if the input start load of the transparent conductive film based on the input load test is 3 g or more and 15 g or less, it has a light operability.

[0082] The present invention having such an input start load is a transparent conductive film used in applications such as resistive film type touch panels, and can also be input by gently touching for people with weak finger pressing force due to age, illness, or other reasons, or people with weak pen pressure.

[0083] If the input start load is 15 g or less, it has a light operability, and thus is preferred. More preferably, it is 13 g or less. Further preferably, it is 11 g or less. On the other hand, if the input start load is 3 g or more, false responses of the touch panel can be prevented, and thus it is preferred. More preferably, it is 5 g or more, and further preferably, it is 8 g or more.

[0084] In the present invention, preferably, the bending resistance of the following thin film bending resistance test is 0.23 N·cm or more and 0.90 N·cm or less, and further, the following average maximum peak height of the surface on the transparent conductive film side of the transparent conductive thin film satisfies the following formula (2-1) and formula (2-2).

[0085] First, the bending resistance based on the thin film bending resistance test will be described. In the thin film bending resistance test, the test piece is placed on a smooth horizontal table with the transparent conductive layer on the upper side. This is to press the transparent conductive thin film from the non-transparent conductive layer side with a pen or finger so that the deformation direction of the transparent conductive thin film is the same. Even for the same transparent conductive thin film, the value of the bending resistance will change depending on whether the transparent conductive layer is on the upper or lower side in the thin film bending resistance test. Therefore, attention needs to be paid during evaluation.

[0086] In addition, when a curable resin layer is disposed between the transparent plastic substrate and the transparent conductive film, the thickness and hardness of the curable resin layer affect the bending resistance. In addition, when curable resin layers are disposed on both sides of the transparent plastic substrate, the balance of the thickness and hardness of the curable resin layer on each side affects the bending resistance.

[0087] If the bending resistance of the transparent conductive thin film is 0.23 N·cm or more, when inadvertently contacting the transparent conductive thin film with a very light force, the transparent conductive thin film is not easily deformed. Therefore, it is difficult to cause electrical contact between the transparent conductive film of the transparent conductive thin film and the transparent conductive film of the ITO glass for the touch panel, and it is easy to prevent misinput. Therefore, it is preferable. In addition, since the pen sliding durability is also excellent, it is preferable. More preferably, it is 0.27 N·cm or more. Further preferably, it is 0.30 N·cm or more.

[0088] On the other hand, if the bending resistance of the transparent conductive thin film is 0.90 N·cm or less, even when pressing from the transparent conductive thin film side with a lower input load using a pen or finger, the transparent conductive thin film is easily deformed. Therefore, the transparent conductive film of the transparent conductive thin film and the transparent conductive film of the ITO glass are easily in electrical contact. Therefore, it has a light operation feeling and is therefore preferable. More preferably, it is 0.80 N·cm or less. Further preferably, it is 0.70 N·cm or less. Particularly preferably, it is 0.60 N·cm or less.

[0089] (Thin film bending resistance test method)

[0090] Collect a test piece of 20 mm × 250 mm from the transparent conductive film, and place the test piece on a horizontal table with a smooth surface with the transparent conductive layer facing up. At this time, only place the 20 mm × 20 mm part of the test piece on the horizontal table, and place the 20 mm × 230 mm part so that it extends outside the horizontal table. In addition, place a heavy object on the 20 mm × 20 mm part of the test piece. At this time, select the weight and size of the heavy object so that there is no gap between the test piece and the horizontal table.

[0091] Next, read the difference in height between the horizontal table and the front end of the film (=δ) with a scale. Next, substitute the value into the following formula (1) to calculate the bending resistance.

[0092] ((g × a × b × L 4 )÷8δ (N·cm) Formula (1)

[0093] g = acceleration due to gravity, a = length of the short side of the test piece, b = specific gravity of the test piece, L = length of the test piece, δ = difference in height between the horizontal table and the front end of the film

[0094] In the present invention, when the film bending resistance test is performed, it is preferable that the bending resistance of the film bending resistance test is 0.23 N·cm or more and 0.90 N·cm or less, and furthermore, the following average maximum peak height of the surface on the transparent conductive film side of the transparent conductive film satisfies the following formula (2-1) and formula (2-2).

[0095] (Average maximum peak height evaluation)

[0096] The average maximum peak height is the average of the maximum peak heights of 5 points. The selection method for the 5 points is as follows: First, select any 1 point A. Next, select 1 point each upstream and downstream 1 cm in the machine direction (MD) of the film with respect to A, for a total of 2 points. Next, select 1 point each to the left and right 1 cm in the transverse direction (TD) of the film with respect to A, for a total of 2 points. The maximum peak height is defined by ISO 25178, and a three-dimensional surface shape measuring device, Bert Scanner (manufactured by Rhomb System Co., Ltd., R5500H-M100 (measurement conditions: wave mode, measurement wavelength 560 nm, objective lens 10 times)) is used to obtain the maximum peak height. In addition, values less than 1 nm are rounded off.

[0097] Average maximum peak height ≥ 4.7 × bending resistance - 1.8 Formula (2-1)

[0098] 0.005 (μm) ≤ average maximum peak height (μm) ≤ 12.000 (μm) Formula (2-2)

[0099] If the maximum peak height of the surface on the transparent conductive film side satisfies Expression (2-1) and Expression (2-2), even when pressed from the transparent conductive film side with a low input load using a pen or finger, it is possible to make electrical contact with the transparent conductive film disposed on the protrusions on the transparent conductive film side of the transparent conductive film and the transparent conductive film of the ITO glass for a touch panel. Therefore, it has a light operability and is thus preferred.

[0100] More preferably, it is the y-section of Expression (2-1), that is, the value shown as “-1.8” in the above Expression (2-1) is -1.7 or more. Further preferably, the y-section of Expression (2-1) is -1.6 or more.

[0101] In addition, if the average maximum peak height is 0.005 (μm) or more, the transparent conductive film can be rolled into a roll without any obstacles, and is thus preferred. More preferably, it is 0.010 (μm) or more. Further preferably, it is 0.020 (μm) or more. In addition, if the average maximum peak height is 12.000 (μm) or less, accidental electrical contact between the transparent conductive film disposed on the protrusions on the transparent conductive film side of the transparent conductive film and the transparent conductive film of the ITO glass for a touch panel is less likely to occur, and thus it is easy to prevent misinput, and is thus preferred. More preferably, it is 11.000 (μm) or less. Further preferably, it is 10.000 (μm) or less. Based on this, it is found that by a proper balance of the bending resistance and the average maximum peak height, light operability and the like are satisfied.

[0102] In the present invention, the maximum value of the maximum peak height in the average maximum peak height evaluation described below exceeds 1.0 times and is 1.4 times or less of the average maximum peak height, and the minimum value of the maximum peak height in the average maximum peak height evaluation is 0.6 times or more and 1.0 times or less of the average maximum peak height. If it is within the above range, the deviation of the input start load is less than ±5%, and is thus preferred.

[0103] If the minimum value of the maximum peak height in the average maximum peak height evaluation is 0.6 times or more of the average maximum peak height, the in-plane distribution of the high protrusions on the transparent conductive film side of the transparent conductive film related to the light operability is balanced. Therefore, when pressing from the transparent conductive film side with a pen or finger, the touch panel can be input with the same input load regardless of the location, and is thus preferred. More preferably, it is 0.7 times or more. Further preferably, it is 0.8 times or more.

[0104] On the other hand, if the maximum value of the maximum peak height in the average maximum peak height evaluation is 1.4 times or less of the average maximum peak height, the in-plane distribution of the high protrusions on the transparent conductive film side of the transparent conductive film related to the brisk operability is balanced. Therefore, when pressing from the transparent conductive film side with a pen or a finger, the input of the touch panel can be performed with the same input load regardless of the location, which is thus preferred. More preferably, it is 1.3 times or less. Even more preferably, it is 1.2 times or less.

[0105] (Average maximum peak height evaluation)

[0106] The average maximum peak height is the average of the maximum peak heights at 5 points. The selection method for the 5 points is as follows: First, arbitrarily select 1 point A. Next, select 1 point each at 1 cm upstream and downstream of A in the machine direction (MD) of the film, for a total of 2 points. Next, select 1 point each at 1 cm to the left and right of A in the transverse direction (TD) of the film, for a total of 2 points. The maximum peak height is defined by ISO 25178, and the maximum peak height is obtained using a three-dimensional surface shape measuring device, Bert scan (manufactured by Rhombus System Co., Ltd., R5500H-M100 (measurement conditions: wave mode, measurement wavelength 560 nm, objective lens 10 times)). In addition, values less than 1 nm are rounded off.

[0107] The transparent conductive film in the present invention is composed of indium-tin composite oxide. In addition, the surface resistance of the transparent conductive film of the present invention is preferably 50 to 900 Ω / square, more preferably 50 to 700 Ω / square. Moreover, the total light transmittance of the transparent conductive film of the present invention is preferably 70 to 95%.

[0108] In the present invention, the thickness of the transparent conductive film is preferably 10 nm or more and 100 nm or less. If the thickness of the transparent conductive film is 10 nm or more, the entire transparent conductive film adheres to the transparent film substrate and the curable resin layer, and the film quality of the transparent conductive film is stable. As a result, the surface resistance value is stable and falls within a preferred range, which is thus preferred. More preferably, the thickness of the transparent conductive film is 13 nm or more, even more preferably 16 nm or more. In addition, if the thickness of the transparent conductive film is 100 nm or less, the grain diameter and crystallinity of the transparent conductive film are appropriate, and furthermore, the total light transmittance reaches a practical level, which is thus preferred. More preferably, it is 50 nm or less, even more preferably 30 nm or less, and particularly preferably 25 nm or less.

[0109] In the present invention, the concentration of tin oxide contained in the transparent conductive film of the transparent conductive film is preferably 0.5 to 40% by mass. It has been found that: the closer the concentration of tin oxide contained in the transparent conductive film of the transparent conductive film is to the concentration of tin oxide contained in the ITO glass for touch panels, the easier it is for the transparent conductive film of the transparent conductive film and the transparent conductive film of the ITO glass to be in electrical contact, and thus it has a light and brisk operability. The concentration of tin oxide contained in the ITO glass for touch panels is generally 10% by mass.

[0110] In the present invention, if the difference between the concentration of tin oxide contained in the transparent conductive film of the transparent conductive film and the concentration of tin oxide contained in the ITO glass for touch panels is 30% by mass or less, it is easy for the transparent conductive film of the transparent conductive film and the transparent conductive film of the ITO glass to be in electrical contact, and thus it has a light and brisk operability, and is therefore preferred.

[0111] The concentration of tin oxide contained in the ITO glass for touch panels is mostly 10% by mass. Therefore, in the present invention, the concentration of tin oxide in the transparent conductive film is preferably 40% by mass or less. More preferably, it is 25% by mass or less. Further preferably, it is 20% by mass or less. Particularly preferably, it is 2% by mass or more and 18% by mass. In addition, if it contains 0.5% by mass or more of tin oxide, the surface resistance of the transparent conductive film becomes a practical level and is preferred. More preferably, the content rate of tin oxide is 1% by mass or more, and particularly preferably, it is 2% by mass or more.

[0112] In one aspect, the transparent conductive film in the present invention has a curable resin layer between the transparent conductive film and the transparent plastic film substrate.

[0113] Furthermore, it is preferred to have a functional layer on the opposite side of the transparent conductive film of the transparent plastic substrate.

[0114] As Figure 2 shown in the structural example shown, it can sequentially have a transparent conductive film 5, a curable resin layer 6, a transparent plastic film substrate 7, and a functional layer 8.

[0115] During the touch panel processing process, the transparent conductive film is heated. At this time, if monomers and oligomers generated from the transparent plastic film substrate precipitate onto the transparent conductive film, it may hinder the light and brisk operability of the touch panel.

[0116] Therefore, by having a curable resin layer between the transparent conductive film and the transparent plastic film substrate, it is possible to block the precipitation of monomers and oligomers on the transparent conductive film, and is therefore preferred.

[0117] In addition, monomers and oligomers precipitated from the transparent plastic substrate may reduce the visual recognition of the transparent conductive film. Therefore, it is preferred to have a curable resin layer and a functional layer on the transparent plastic film substrate.

[0118] In addition, by having a curable resin layer and a functional layer, the bending resistance of the transparent conductive film can be further adjusted to a preferred range in the present invention.

[0119] The curable resin layer and the functional layer according to the present invention can more effectively discover various characteristics such as pen sliding durability. In particular, in the present invention, by having a curable resin layer and a functional layer, the bending resistance of the transparent conductive film of the present invention can be adjusted, and the input start load can be adjusted to a given range. On this basis, excellent visual recognition can be achieved.

[0120] It should not be construed as a specific theory, but in the present invention, by having both a curable resin layer and a functional layer, a light operation feeling and more accurate input performance can be represented in a resistive film type touch panel.

[0121] In addition, by having a curable resin layer on the transparent plastic film substrate, in addition to increasing the close contact force of the transparent conductive film, the force applied to the transparent conductive film can be dispersed. Therefore, cracks, peeling, wear, etc. can be suppressed with respect to the transparent conductive film in the pen sliding durability test, so it is preferred. In addition, by having a functional layer on the transparent plastic film substrate, damage caused by input with a pen or the like is not likely to occur, so it is preferred.

[0122] In one aspect, the transparent conductive film in the present invention laminates an easily adhesive layer on at least one side of the transparent plastic film substrate.

[0123] For example, the transparent conductive film in the present invention preferably includes an easily adhesive layer in either one between the transparent plastic film substrate and the curable resin layer, or between the transparent plastic film substrate and the functional layer, or both include an easily adhesive layer. In Figure 3 , Figure 4 , Figure 5 shows a structural example. In these figures, an easily adhesive layer 9 is arranged. Other symbols are synonymous with Figure 2 .

[0124] By having an easily adhesive layer, the curable resin layer and the functional layer can be firmly adhered to the transparent plastic film substrate, so that peeling of the curable resin layer and the functional layer caused by external force can be more effectively suppressed, so it is preferred.

[0125] The transparent conductive film of the present invention is a transparent conductive film in which an indium-tin composite oxide transparent conductive film is laminated on at least one surface of a transparent plastic film substrate, and preferably the on-resistance of the transparent conductive film obtained by the following pen sliding durability test is 10 kΩ or less.

[0126] (Pen Sliding Durability Test)

[0127] The transparent conductive film involved in the present invention is used as one panel. As the other panel, a transparent conductive film made of an indium-tin composite oxide film (tin oxide content: 10% by mass) is used. The indium-tin composite oxide film is formed on a glass substrate by sputtering and has a thickness of 20 nm. These two panels are arranged with epoxy beads having a diameter of 30 μm therebetween so that the transparent conductive films face each other, and the panel on the film side and the panel on the glass side are pasted with a double-sided tape having a thickness of 170 μm to fabricate a touch panel. Next, a load of 2.5 N is applied to a polyacetal pen (front end shape: 0.8 mm R), and a linear sliding test of 50,000 reciprocations is performed on the touch panel. In this test, the load of the pen is applied to the surface of the transparent conductive film involved in the present invention. The sliding distance at this time is set to 30 mm, and the sliding speed is 180 mm / second. After this sliding durability test, the conduction resistance (the resistance value when the movable electrode (film electrode) contacts the fixed electrode) when pressing the sliding portion with a pen load of 0.8 N is measured.

[0128] In the present invention, if the conduction resistance of the transparent conductive film based on the pen sliding durability test is 10 kΩ or less, even if the touch panel is continuously input with a pen, cracks, peeling, wear, etc. with respect to the transparent conductive film can be suppressed, and thus it is preferred. In one embodiment, the conduction resistance can be 9.5 kΩ or less, more preferably 5 kΩ or less. For example, the conduction resistance can be 3 kΩ or less, can be 1.5 kΩ or less, and is preferably 1 kΩ or less.

[0129] Examples of the conduction resistance are 5 kΩ or more, can be 3 kΩ or more, and are preferably 0 kΩ or more.

[0130] By making the conduction resistance within such a range, even if the touch panel is continuously input with a pen, cracks, peeling, wear, etc. with respect to the transparent conductive film can be suppressed.

[0131] In one embodiment, these upper and lower limits can also be appropriately combined.

[0132] For example, in the adhesion test according to JIS K5600-5-6:1999 on the surface of the transparent conductive film of the transparent conductive film of the present invention, the residual area ratio of the transparent conductive film is 95% or more. For the transparent conductive film of the present invention, even when the adhesion test (JIS K5600-5-6:1999) is carried out on the surface of the transparent conductive film, the residual area ratio of the transparent conductive film is preferably 95% or more, more preferably the peeling area of the transparent conductive film is 99% or more, and particularly preferably 99.5% or more. By the residual area ratio of the transparent conductive film in the adhesion test being within the above range, the transparent conductive film and the layers in contact with the transparent conductive film such as the transparent plastic film substrate and the curable resin layer are in close contact. Therefore, even when continuously inputting to the touch panel with a pen, cracks, peeling, wear, etc. with respect to the transparent conductive film can be suppressed. Furthermore, even when applying a strong force greater than the assumed normal use, cracks, peeling, etc. with respect to the transparent conductive film can be suppressed. Therefore, it is preferred.

[0133] For example, in the adhesion test according to JIS K5600-5-6:1999 on the surface of the functional layer of the transparent conductive film of the present invention, the residual area ratio of the functional layer is 95% or more. For the transparent conductive film of the present invention, even when the adhesion test (JIS K5600-5-6:1999) is carried out on the functional layer surface, the residual area ratio of the functional layer surface is preferably 95% or more, more preferably the residual area ratio of the functional layer surface is 99% or more, and particularly preferably 99.5% or more.

[0134] In the transparent conductive film in which the functional layer does not peel off in the adhesion test, since the transparent plastic film substrate is in close contact with the functional layer, even when continuously inputting to the touch panel with a pen, appearance defects such as cracks, peeling, and wear of the functional layer are suppressed. Furthermore, even when applying a strong force greater than the assumed normal use, the functional layer will relieve the strong force. Therefore, cracks, peeling, etc. of the transparent conductive film are suppressed. Therefore, it is preferred.

[0135] The manufacturing method for obtaining the transparent conductive film of the present invention is not particularly limited. For example, the following manufacturing methods can be preferably exemplified.

[0136] As a method for forming a transparent conductive film of indium-tin composite oxide on at least one surface of a transparent plastic film substrate, a sputtering method is preferably used. In order to manufacture a transparent conductive film with high productivity, a so-called roll sputtering device that supplies a film roll and winds the film roll after film formation is preferably used. The following method can be preferably adopted: in a film formation atmosphere, a mass flow controller is used to introduce an inert gas and oxygen, a sintered target of indium-tin composite oxide is used, the thickness of the transparent conductive film of indium-tin composite oxide is adjusted to 10 to 100 nm, and a transparent conductive film is formed on the transparent plastic film. In order to improve production efficiency, multiple sintered targets of indium-tin composite oxide can also be provided in the direction of film flow. In addition, in the film formation atmosphere, a mass flow controller is used, and a gas containing hydrogen atoms can also be introduced (as long as it is a gas containing hydrogen atoms such as hydrogen, ammonia, hydrogen + argon mixed gas, etc., there is no particular limitation. Among them, water is excluded). If there is a lot of water in the film formation atmosphere, the film quality of the transparent conductive film will deteriorate, the surface resistance value will deviate from the preferred range, or the originally crystallized transparent conductive film will not crystallize, etc., which will have an adverse effect on the film quality of the transparent conductive film. Therefore, the moisture content in the film formation atmosphere is also an important factor. By controlling the central value (the value in the middle of the maximum value and the minimum value) of the ratio of the water partial pressure in the film formation atmosphere during sputtering of the film roll to the inert gas to 7.00×10 -3 The following can suppress the deterioration of the film quality of the transparent conductive film, so it is preferable. In order to control the moisture content in the film formation atmosphere, in addition to the rotary pump, turbo molecular pump, and cryopump that are often used as the exhaust device of the sputtering machine, the following bombardment process, the limitation of the height difference of the unevenness on the end face of the film roll, pasting a protective film with low water absorption on the opposite side of the surface where the transparent conductive film is formed, etc. can reduce the amount of moisture released from the film during the formation of the transparent conductive film, so it is preferable. In addition, it is preferable to make the film temperature during sputtering below 0 °C and form a transparent conductive film on the transparent plastic film. The film temperature during film formation is replaced by the set temperature of a temperature controller that adjusts the temperature of the center roller in contact with the traveling film. Here, Figure 1 FIG. shows a schematic diagram of an example of a sputtering device preferably used in the present invention. The traveling film 1 partially contacts the surface of the center roller 2 and travels. An indium-tin sputtering target 4 is provided via a chimney 3, and a film of indium-tin composite oxide is deposited and laminated on the surface of the film 1 traveling on the center roller 2. The center roller 2 is temperature-controlled by a temperature controller (not shown). If the film temperature is below 0 °C, the release of impurity gases such as water and organic gases from the film that deteriorate the film quality of the transparent conductive film can be suppressed, so it is preferable. In addition, the surface resistance and total light transmittance of the transparent conductive film reach practical levels, and it is preferable to add oxygen during sputtering.

[0137] In the control of the amount of moisture during the formation of indium-tin composite oxide film on a plastic film, there are the following two reasons why the actually observed amount of moisture during film formation is preferably compared with the observed vacuum degree.

[0138] The first reason is that when forming a film on a plastic film by sputtering, the film is heated and moisture is released from the film, so the amount of moisture in the film-forming atmosphere increases compared with the amount of moisture when measuring the vacuum degree reached, and thus it is more accurate to express it in terms of the amount of moisture during film formation than in terms of the vacuum degree reached.

[0139] The second reason is the case of a device that inputs a large amount of transparent plastic film. In such a device, the film is input in the form of a film roll. If the film is input into the vacuum chamber as a roll, the water on the outer layer part of the roll is easily shed, but the water on the inner layer part of the roll is difficult to shed. This is because when measuring the vacuum degree reached, the film roll stops, but during film formation, the film roll moves forward, so the inner layer part of the film roll containing a large amount of water is unrolled, and thus the amount of moisture in the film-forming atmosphere increases compared with the amount of moisture when measuring the vacuum degree reached. In the present invention, when controlling the amount of moisture in the film-forming atmosphere, it is possible to preferably cope with it by observing the ratio of the moisture pressure in the film-forming atmosphere during sputtering to the inert gas.

[0140] Preferably, before forming the transparent conductive film, the film is passed through a bombardment process. The so-called bombardment process means that in a state where only an inert gas such as argon or a mixed gas of a reactive gas such as oxygen and an inert gas is introduced, a voltage is applied to generate a discharge to generate plasma. Specifically, it is preferable to bombard the film by RF sputtering using a SUS target or the like. Since the film is exposed to plasma through the bombardment process, water and organic components are released from the film, and the water and organic components released from the film during the formation of the transparent conductive film are reduced, so the film quality of the transparent conductive film becomes good, and thus it is preferable. In addition, since the layer in contact with the transparent conductive film is activated through the bombardment process, the adhesion of the transparent conductive film is improved, so the pen sliding durability is improved, and thus it is preferable.

[0141] For the film roll used for forming the transparent conductive film, the height difference between the most convex part and the most concave part at the roll end face is preferably 10 mm or less. If it is 10 mm or less, it is not easy to release water and organic components from the film end face when the film roll is put into the sputtering device, so the film quality of the transparent conductive film becomes good, and thus it is preferable.

[0142] In the film (transparent plastic film substrate) for forming the transparent conductive film, it is preferable to paste a protective film with a low water absorption rate on the opposite side of the surface for forming the transparent conductive film. By pasting a protective film with a low water absorption rate, it is not easy to release gases such as water from the film substrate, and the film quality of the transparent conductive film becomes good, and thus it is preferable. As the substrate of the protective film with a low water absorption rate, polyethylene, polypropylene, cycloolefin, etc. are preferable.

[0143] In the method of forming a transparent conductive film of crystalline indium-tin composite oxide on at least one surface of a transparent plastic film substrate, it is preferable to introduce oxygen during sputtering. If oxygen is introduced during sputtering, no adverse conditions will occur due to the lack of oxygen in the transparent conductive film of indium-tin composite oxide. The surface resistance of the transparent conductive film is low, and the total light transmittance is high, which is preferable. Therefore, in order to make the surface resistance and the total light transmittance of the transparent conductive film reach a practical level, it is preferable to introduce oxygen during sputtering. In addition, the total light transmittance of the transparent conductive film of the present invention is preferably 70 to 95%.

[0144] The transparent conductive film of the present invention is preferably heat-treated at 80 to 200 °C for 0.1 to 12 hours in an oxygen-containing atmosphere after forming and laminating a transparent conductive film of indium-tin composite oxide on a transparent plastic film substrate. If it is 80 °C or higher, it is preferable for the purpose of improving the pen sliding durability and in the case where it is necessary to improve the crystallinity of the transparent conductive film. If it is 200 °C or lower, it is preferable to ensure the flatness of the transparent plastic film.

[0145] <Transparent plastic film substrate>

[0146] The transparent plastic film substrate used in the present invention refers to a film obtained by melt-extruding or solution-extruding an organic polymer in a film shape and stretching, cooling, and thermally fixing it in the longitudinal direction and / or the width direction as needed. 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, polyethersulfone, polyetheretherketone, polycarbonate, polyarylate, cellulose propionate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyetherimide, polyphenylene sulfide, polyphenylene ether, polystyrene, syndiotactic polystyrene, norbornene-based polymers, etc.

[0147] Among these organic polymers, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene 2,6-naphthalate, syndiotactic polystyrene, norbornene-based polymers, polycarbonate, polyarylate, etc. are preferable. In addition, these organic polymers can copolymerize a small amount of monomers of other organic polymers or blend other organic polymers.

[0148] Within the scope not impairing the object of the present invention, the transparent plastic film substrate used in the present invention can be subjected to surface activation treatments such as corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, ozone treatment, etc. on the film.

[0149] In the present invention, the thickness of the transparent plastic film substrate of the transparent conductive film is preferably in the range of 100 μm or more and 240 μm or less, more preferably 120 μm or more and 220 μm or less. If the thickness of the plastic film is 100 μm or more, the mechanical strength is maintained. In particular, when used for a touch panel, the deformation during pen input is small and the pen sliding durability is excellent, so it is preferred. On the other hand, when the thickness is 240 μm or less, when used for a touch panel, a light operability is maintained, so it is preferred.

[0150] If a curable resin layer is laminated on the transparent plastic film substrate, monomers and oligomers generated from the transparent plastic film substrate can be blocked from depositing on the transparent conductive film, so that the light operability of the touch panel is not hindered, so it is preferred. In addition, the transparent conductive film and the curable resin layer are firmly adhered to each other, and the force applied to the transparent conductive film can be dispersed. Therefore, cracks, peeling, wear, etc. can be suppressed with respect to the transparent conductive film in the pen sliding durability test, so it is preferred. In order to improve the adhesion force between the transparent plastic film substrate and the curable resin layer, it is preferred to provide an easy-bonding layer between the transparent plastic film substrate and the curable resin layer.

[0151] If a functional layer is laminated on the transparent plastic film substrate, monomers and oligomers generated from the transparent plastic film substrate can be blocked from depositing, and the reduction of the visual recognition of the transparent conductive film can be suppressed, so it is preferred. In order to adjust the bending resistance of the transparent conductive film, it is preferred to have a functional layer on the transparent plastic film substrate. In addition, by having a functional layer on the transparent plastic film substrate, damage caused by input with a pen or the like is not likely to occur, so it is preferred.

[0152] In addition, as the resin contained in the curable resin layer and the functional layer preferably used in the present invention, there is no particular limitation as long as it is a resin that is cured by applying energy such as heating, ultraviolet irradiation, or electron beam irradiation. Examples thereof include silicone resin, acrylic resin, methacrylic resin, epoxy resin, melamine resin, polyester resin, polyurethane resin, etc. From the viewpoint of productivity, it is preferred to use an ultraviolet curable resin as the main component.

[0153] The resins contained in the curable resin layer and the functional layer may be the same resin or different resins.

[0154] As such an ultraviolet curable resin, for example, a polyfunctional polyurethane acrylate resin synthesized from a polyfunctional acrylate resin such as an acrylate or methacrylate of a polyol, a diisocyanate, a polyol, and a hydroxyalkyl ester of acrylic acid or methacrylic acid can be cited. If necessary, a monofunctional monomer such as vinylpyrrolidone, methyl methacrylate, or styrene can be added to these polyfunctional resins for copolymerization.

[0155] In addition, in order to improve the adhesion between the transparent conductive film and the curable resin layer, it is effective to treat the surface of the curable resin layer by the method described below. As a specific method, the following can be cited: a discharge treatment method such as glow or corona discharge irradiation to increase carbonyl, carboxyl, and hydroxyl groups; a chemical agent treatment method such as treatment with an acid or a base to increase polar groups such as amino, hydroxyl, and carbonyl groups, etc.

[0156] The ultraviolet curable resin is usually used by adding a photosensitizer. As the photosensitizer, a known compound that absorbs ultraviolet rays and generates free radicals can be used without particular limitation. As such a photosensitizer, for example, various benzoin compounds, benzophenone compounds, diphenylmethanone compounds, etc. can be cited. The addition amount of the photosensitizer is preferably increased to 1 to 5 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin.

[0157] In addition, in the present invention, in addition to the curable resin as the main constituent, it is preferable to use inorganic particles and organic particles for the curable resin layer and the functional layer at the same time. By dispersing the inorganic particles and organic particles in the curable resin, unevenness can be formed on the surfaces of the curable resin layer and the functional layer, and the surface roughness in a wide area can be improved.

[0158] In the present invention, by increasing the surface roughness of the curable resin layer, the bending resistance of the transparent conductive film can be adjusted to a more preferable range in the present invention. In addition, various characteristics such as pen sliding durability, anti-Newton ring property, and film winding property can be found more effectively.

[0159] In the present invention, by increasing the surface roughness of the functional layer, the bending resistance of the transparent conductive film can be adjusted to a more preferable range in the present invention. In addition, various characteristics such as film winding property, writing feeling of a pen, and touch feeling of a finger can be found more effectively.

[0160] Examples of the inorganic particles include silica and the like. Examples of the organic particles include polyester resin, polyolefin resin, polystyrene resin, and polyamide resin, etc. The particles contained in the curable resin layer and the functional layer may be the same particles or different particles.

[0161] In addition to inorganic particles and organic particles, in addition to the curable resin as the main constituent, it is also preferable to use a resin incompatible with the curable resin at the same time. By using a small amount of an incompatible resin in the matrix curable resin at the same time, phase separation can occur in the curable resin, and the incompatible resin can be dispersed in a particulate form. Through the dispersed particles of the incompatible resin, unevenness is formed on the surfaces of the curable resin layer and the functional layer, and the surface roughness in a wide area can be improved.

[0162] Examples of the incompatible resin include polyester resin, polyolefin resin, polystyrene resin, polyamide resin, etc.

[0163] Here, as an example, the mixing ratio in the case of using inorganic particles in the curable resin layer is shown. With respect to 100 parts by mass of the ultraviolet curable resin, the inorganic particles are preferably 0.1 part by mass or more and 30 parts by mass or less, more preferably 0.1 part by mass or more and 25 parts by mass or less, and particularly preferably 0.1 part by mass or more and 20 parts by mass or less. If the mixing amount of the inorganic particles is 0.1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the ultraviolet curable resin, the convex portions formed on the surface of the curable resin layer will not be too small, an effective average maximum peak height can be imparted, and a light operability for the touch panel can be obtained. Furthermore, there are a few surface protrusions on the transparent conductive film, so the film winding property can also be maintained, thus it is preferred. In addition, when using inorganic particles in the curable resin layer, when the mixing ratio is within the above range, there is a tendency for the average maximum peak height of the curable resin layer to become higher.

[0164] In addition, when using inorganic particles in the curable resin layer, when the mixing ratio is relatively high within the above range, there is a tendency to increase the bending resistance of the transparent conductive film.

[0165] Here, as an example, the mixing ratio in the case of using inorganic particles in the functional layer is shown. With respect to 100 parts by mass of the ultraviolet curable resin, the inorganic particles are preferably 0.1 part by mass or more and 60 parts by mass or less.

[0166] When using inorganic particles in the functional layer, when the mixing ratio is relatively high within the above range, there is a tendency to reduce the bending resistance of the transparent conductive film. If the mixing amount of the inorganic particles is 0.1 part by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the ultraviolet curable resin, the bending resistance of the transparent conductive film can be adjusted to an appropriate value according to the present invention, thus it is preferred. In addition, since the surface protrusions can be made on the functional layer within the range that does not damage the effects of the present invention, the film winding property can also be maintained, thus it is preferred.

[0167] The ultraviolet curable resin, photoinitiator, and inorganic particles, organic particles, and resins incompatible with the ultraviolet curable resin are respectively dissolved in a common solvent to prepare a coating solution. The solvent used is not particularly limited. For example, alcohol solvents such as ethanol and isopropyl alcohol, ester solvents such as ethyl acetate and butyl acetate, ether solvents such as dibutyl ether and ethylene glycol monoethyl ether, ketone solvents such as methyl isobutyl ketone and cyclohexanone, and aromatic hydrocarbon solvents such as toluene, xylene, and solvent naphtha can be used alone or in combination.

[0168] The concentration of the resin component in the coating liquid (i.e., the solid component concentration) can be appropriately selected in consideration of the viscosity and the like corresponding to the coating method. For example, the total amount of the ultraviolet curable resin, the photoinitiator, and the high molecular weight polyester resin usually accounts for 20 to 80% by mass in the coating liquid. When the concentration of the resin component is high, the average maximum peak height of the cured resin layer tends to become higher. In addition, if necessary, other known additives such as silicone leveling agents can also be added to the coating liquid.

[0169] In the present invention, the prepared coating liquid is coated on a transparent plastic film substrate. The coating method is not particularly limited, and known methods such as a bar coating method, a gravure coating method, and a reverse coating method can be used.

[0170] In the subsequent drying process, the solvent in the coated coating liquid is evaporated and removed. In this process, the high molecular weight polyester resin uniformly dissolved in the coating liquid becomes particles and precipitates in the ultraviolet curable resin. After drying the coating film, ultraviolet rays are irradiated on the plastic film, whereby the ultraviolet curable resin is crosslinked and cured to form a cured resin layer and a functional layer. In this curing process, the particles of the high molecular weight polyester resin are fixed in the hard coat, and protrusions are formed on the surfaces of the cured resin layer and the functional layer, increasing the surface roughness in a wide area.

[0171] In addition, the thickness of the cured resin layer is preferably in the range of 0.1 μm or more and 15 μm or less. More preferably, it is in the range of 0.5 μm or more and 10 μm or less, and particularly preferably in the range of 1 μm or more and 8 μm or less. When the thickness of the cured resin layer is 0.1 μm or more, it is preferable to form sufficient protrusions. On the other hand, if it is 15 μm or less, the productivity is good, so it is preferable. In addition, if the cured resin layer is thick, the bending resistance of the transparent conductive film tends to increase.

[0172] In addition, the thickness of the functional layer is preferably in the range of 0.1 μm or more and 15 μm or less. More preferably, it is in the range of 0.5 μm or more and 15 μm or less, and particularly preferably in the range of 1 μm or more and 10 μm. If the functional layer is thick, the bending resistance of the transparent conductive film tends to decrease. When the thickness of the functional layer is 0.1 μm or more, it is preferable to form sufficient protrusions. On the other hand, if it is 15 μm or less, the productivity is more preferable.

[0173] Regarding the addition amounts of the inorganic particles, organic particles, and incompatible resins contained in the cured resin layer, and further the influence of the thickness of the cured resin layer on the bending resistance of the transparent conductive film, by appropriately selecting the addition amounts of the inorganic particles, organic particles, and incompatible resins contained in the functional layer, and the thickness of the functional layer, the bending resistance of the transparent conductive film can be made the above-mentioned appropriate value.

[0174] Therefore, in the present invention, if only the functional layer is provided, the effects achieved by the present invention cannot be obtained. By having the features involved in the present invention, the bending resistance of the transparent conductive film can be effectively improved.

[0175] In one embodiment, the thickness of the cured resin layer and the thickness of the functional layer may be the same. Additionally, in another embodiment, for example, the absolute value of the difference between the thickness of the cured resin layer and the thickness of the functional layer has the following relationship.

[0176] 0.1μm ≤ |thickness of cured resin layer - thickness of functional layer| ≤ 3μm

[0177] In this way, in the present invention, by setting a difference in the thickness of the cured resin layer and the thickness of the functional layer, the bending resistance of the transparent conductive film can also be adjusted to a more preferable range in the present invention. Moreover, various properties such as pen sliding durability can be more effectively exhibited, and a transparent conductive film with a light and easy operability can be obtained.

[0178] Furthermore, it is preferred that the particle mass per unit volume of the cured resin layer is different from the particle mass per unit volume of the functional layer.

[0179] The easy - adhesion layer according to the present invention is preferably formed from a composition containing a polyurethane resin, a cross - linker, and a polyester resin. As the cross - linker, blocked isocyanate is preferred, further preferably blocked isocyanate with a functionality of 3 or more, and particularly preferably blocked isocyanate with a functionality of 4 or more. The thickness of the easy - adhesion layer is preferably 0.001μm or more and 2.00μm or less.

[0180] In one embodiment, the present invention provides a resistive film - type touch panel having the transparent conductive film according to the present invention. In addition to the transparent conductive film of the present invention, the touch panel may also have well - known components. If it is the transparent conductive film for the resistive film - type touch panel of the present invention, the above - mentioned various effects can be better exerted in the touch panel.

[0181] Examples

[0182] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited by any of these examples. Additionally, various measurements and evaluations in the examples are carried out by the following methods.

[0183] (1) Total light transmittance

[0184] According to JIS - K7361 - 1:1997, using NDH - 2000 manufactured by Nippon Denshoku Industries Co., Ltd., the total light transmittance is measured.

[0185] (2) Surface resistance value

[0186] The measurement was carried out by the four-terminal method in accordance with JIS-K7194:1994. The measuring machine used was Lotesta AX MCP-T370 manufactured by Mitsubishi Chemical Analytech Co., Ltd.

[0187] (3) Average maximum peak height evaluation

[0188] The average maximum peak height is the average of the maximum peak heights at 5 points. The selection method for the 5 points is as follows: First, arbitrarily select 1 point A. Next, select 1 point each upstream and downstream 1 cm in the machine direction (MD) of the film with respect to A, for a total of 2 points. Next, select 1 point each to the left and right 1 cm in the transverse direction (TD) of the film with respect to A, for a total of 2 points. The maximum peak height is specified by ISO 25178, and the maximum peak height was obtained using a three-dimensional surface shape measuring device, Burt Scanner (manufactured by Rhodamine Systems Co., R5500H-M100 (measurement conditions: wave mode, measurement wavelength 560 nm, objective lens 10 times)). In addition, values less than 1 nm are rounded off.

[0189] (4) Crystallinity of the transparent conductive film

[0190] The film specimen piece laminated with the transparent conductive film layer was cut into a size of 1 mm × 10 mm, and was pasted onto the upper surface of an appropriate resin block with the conductive film surface facing outward. After trimming it, an ultra-thin section approximately parallel to the film surface was produced by the technique of a general ultra-microtome.

[0191] This section was observed with a transmission electron microscope (manufactured by JEOL Ltd., JEM-2010), and the surface portion of the conductive film without significant damage was selected, and photographed at an accelerating voltage of 200 kV and a direct magnification of 40,000 times.

[0192] As an evaluation of the crystallinity of the transparent conductive film, the ratio of crystal grains observed under the transmission electron microscope, that is, the crystallinity, was observed.

[0193] (5) Thickness (film thickness) of the transparent conductive film

[0194] The film specimen piece laminated with the transparent conductive film layer was cut into a size of 1 mm × 10 mm and embedded in an epoxy resin for electron microscopy. It was fixed to the specimen holder of an ultra-microtome, and a thin cross-section parallel to the short side of the embedded specimen piece was produced. Next, at the non-significantly damaged part of the film in this section, a transmission electron microscope (manufactured by JEOL Ltd., JEM-2010) was used to photograph at an accelerating voltage of 200 kV and a viewing magnification of 10,000 times in bright field, and the film thickness was obtained from the obtained photograph.

[0195] (6) Pen sliding durability test

[0196] A transparent conductive film was used as one panel, and as the other panel, a transparent conductive film composed of an indium-tin composite oxide film (tin oxide content: 10% by mass) was used. The indium-tin composite oxide film was formed on a glass substrate by sputtering and had a thickness of 20 nm. These two panels were arranged with epoxy beads having a diameter of 30 μm therebetween so that the transparent conductive films faced each other, and a touch panel was fabricated. Next, a load of 2.5 N was applied to a polyacetal pen (tip shape: 0.8 mm R), and a linear sliding test with 50,000 reciprocations was performed on the touch panel. The sliding distance at this time was 30 mm, and the sliding speed was 180 mm / second. After this sliding durability test, the conduction resistance (the resistance value when the movable electrode (thin film electrode) contacts the fixed electrode) was measured when pressing the sliding portion with a pen load of 0.8 N. The conduction resistance is preferably 10 kΩ or less.

[0197] (7) Measurement of the content ratio of tin oxide contained in the transparent conductive film

[0198] A sample (about 15 cm 2 ) was cut out, 20 ml of 6 mol / l hydrochloric acid was added to a quartz Erlenmeyer flask, and the film was sealed so that there was no acid volatilization. It was left for 9 days while shaking frequently at room temperature to dissolve the transparent conductive film. The residual film was taken out, and the hydrochloric acid in which the transparent conductive film was dissolved was used as the measurement solution. Using an ICP emission analysis device (manufacturer name: Rigaku; device specification: CIROS-120EOP), In and Sn in the dissolution solution were obtained by the calibration curve method. The measurement wavelengths of each element were selected to be wavelengths with no interference and high sensitivity. In addition, standard solutions were prepared by diluting commercially available In and Sn standard solutions.

[0199] (8) Input load test method

[0200] A transparent conductive film (size: 220 mm × 135 mm) was used as one panel, and as the other panel, a transparent conductive film A composed of an indium-tin composite oxide film (tin oxide content: 10% by mass) was used. The indium-tin composite oxide film was formed on a glass substrate (size: 232 mm × 151 mm) by sputtering and had a thickness of 20 nm.

[0201] Epoxy resins (longitudinal 60 μm × transverse 60 μm × height 5 μm) as dot spacers were arranged in a square lattice pattern with a 4 mm pitch on the side of the transparent conductive film A of the glass substrate with an indium-tin composite oxide film, hereinafter also referred to as ITO glass.

[0202] Next, starting from any one of the four corners of the ITO glass, a double-sided tape (thickness: 105 μm, width 6 mm) can be pasted on the transparent conductive film A side of the ITO glass to form a rectangle of 190 mm × 135 mm.

[0203] Next, on the double-sided tape pasted on the ITO glass, the transparent conductive film B side of the transparent conductive film is pasted, and the transparent conductive film A and the transparent conductive film B are laminated face to face.

[0204] At this time, one short side of the transparent conductive film extends out from the ITO glass.

[0205] Next, connect the ITO glass and the transparent conductive film with a tester.

[0206] Next, apply a load from the transparent conductive film side using a polyacetal pen (front end shape: 0.8 mm R), and set the load value when the resistance value measured by the tester is stable as the input start load.

[0207] The position where the load is applied with the pen is the central area surrounded by four point spacers, and the average value of the input start loads at three points is calculated.

[0208] The position where the load is applied with the pen is as Figure 6 shown, which is the central area of the four point spacers. In addition, the input start load is the average value of any three points more than 50 mm away from the double-sided tape. Round off the decimal point.

[0209] (9) Thin film flexural property test method

[0210] Collect a test piece of 20 mm × 250 mm from the transparent conductive film, and place the test piece on a smooth horizontal table with the transparent conductive layer facing up. At this time, only the 20 mm × 20 mm part of the test piece is placed on the horizontal table, and the 20 mm × 230 mm part is placed outside the horizontal table. In addition, place a heavy object on the 20 mm × 20 mm part of the test piece. At this time, select the weight and size of the heavy object so that there is no gap between the test piece and the horizontal table. Next, read the difference in height between the horizontal table and the front end of the film (=δ) with a scale. Next, substitute the values into the following formula (1) to calculate the flexural property.

[0211] (g×a×b×L 4 )÷8δ (N·cm) Formula (1)

[0212] g = acceleration due to gravity, a = length of the short side of the test piece, b = specific gravity of the test piece, L = length of the test piece, δ = difference in height between the horizontal table and the front end of the film

[0213] (10) Evaluation of the maximum value of the maximum peak height relative to the average maximum peak height and the minimum value of the maximum peak height

[0214] Divide the maximum value and the minimum value among the five maximum peak height values measured in the average maximum peak height evaluation by the average maximum peak height.

[0215] (11) Adhesion test

[0216] Performed in accordance with JIS K5600-5-6:1999.

[0217] The results in the following table represent the adhesion in terms of the residual area ratio. The highest value of the residual area ratio is 100%. The closer the residual area ratio of the adhesion test in the table is to 100%, the less the peeling area.

[0218] The transparent plastic film substrate used in the examples and comparative examples is a biaxially oriented transparent PET film (manufactured by Toyobo Co., Ltd., A4380, thickness is described in Tables 1 and 2) having an easy-bonding layer on both sides. In 100 parts by mass of an acrylic resin containing a photoinitiator (manufactured by Dainichi Seika Kogyo Co., Ltd., SEIKA Beam (registered trademark) EXF-01J) as the curable resin layer, the amounts of silica particles (manufactured by Nissan Chemical Industries, Ltd., SNOWTEX ZL) described in Tables 1 and 2 are mixed, and a mixed solvent of toluene / MEK (8 / 2: mass ratio) as the solvent is added so that the solid content concentration becomes the values described in Tables 1 and 2, and stirred to dissolve uniformly to prepare a coating liquid (hereinafter, this coating liquid is referred to as coating liquid A). The prepared coating liquid is coated using a Meyer rod so that the thickness of the coating film is the value described in Tables 1 and 2. After drying at 80 °C for 1 minute, ultraviolet rays (light quantity: 300 mJ / cm 2 ) are irradiated using an ultraviolet irradiation device (manufactured by EYEGRAPHICS Co., Ltd., UB042-5AM-W type) to cure the coating film.

[0219] In addition, under the conditions shown in Tables 1 to 4, a functional layer is provided on the surface of the transparent plastic substrate opposite to the above curable resin layer.

[0220] (Examples 1 to 7)

[0221] Each example level is carried out as follows under the conditions shown in Table 1.

[0222] Put the film into a vacuum chamber and evacuate to 1.5×10 -4 Pa. Next, after introducing oxygen, argon as an inert gas is introduced to make the total pressure 0.6 Pa.

[0223] At 3 W / cm 2Power is applied to a sintered target of indium-tin composite oxide or a sintered target of indium oxide without tin oxide at a power density of 10000 W, and a transparent conductive film is formed by a DC magnetron sputtering method. The film thickness is controlled by changing the speed at which the film passes over the target. In addition, the ratio of the water partial pressure to the inert gas in the film-forming atmosphere during sputtering is measured using a gas analyzer (manufactured by Inficon, Transpector XPR3). At the level of each embodiment, in order to adjust the ratio of the water partial pressure to the inert gas in the film-forming atmosphere during sputtering, the presence or absence of a bombardment process, the height difference of the end face of the film roller, and the temperature of the heat medium of the temperature controller that controls the temperature of the center roller at which the film contacts the moving film are adjusted as described in Table 1. The temperature exactly in the middle of the maximum and minimum values of the temperature from the beginning of film formation on the film roller to the end of film formation is recorded in Table 1 as the center value.

[0224] The thin film on which the transparent conductive film was formed and laminated was subjected to the heat treatment described in Table 1, and then the measurement was performed. The measurement results are shown in Tables 1, 3 and 4.

[0225] (Comparative Examples 1 to 7)

[0226] Under the conditions described in Table 2, a transparent conductive film was produced and evaluated in the same manner as in Example 1. The results are shown in Tables 2 to 4.

[0227] [Table 1]

[0228]

[0229] [Table 2]

[0230]

[0231] [Table 3]

[0232]

[0233] [Table 4]

[0234]

[0235] As shown in Tables 1 to 4, the input start loads of the transparent conductive films described in Examples 1 to 7 are within the range of the present invention, and therefore, when used in a resistive film touch panel, they have excellent light operability and excellent pen sliding durability, and have both characteristics. However, Comparative Examples 1 to 7 cannot have both light operability and pen sliding durability.

[0236] --Industrial Availability--

[0237] As described above, according to the present invention, it is possible to provide a transparent conductive film having a light operability and excellent pen-sliding durability, which is extremely useful in applications such as resistive film type touch panels.

[0238] --Explanation of Reference Numerals--

[0239] 1. Film

[0240] 2. Center Roll

[0241] 3. Chimney

[0242] 4. Target of Indium-Tin Composite Oxide

[0243] 5. Transparent Conductive Film

[0244] 6. Curing-Type Resin Layer

[0245] 7. Transparent Plastic Film Substrate

[0246] 8. Functional Layer

[0247] 9. Easy-Adhesion Layer

[0248] 10. ITO Glass

[0249] 11. Dot Spacer

[0250] 12. Position where a load is applied by a pen.

Claims

1. A transparent conductive film, wherein, a transparent conductive film of indium-tin composite oxide is laminated on at least one surface side of a transparent plastic film substrate, the input start load of the transparent conductive film obtained by the following input load test is 3 g or more and 15 g or less, in the input load test method, a transparent conductive film with dimensions of 220 mm × 135 mm is used as one panel, and as the other panel, a transparent conductive film A composed of an indium-tin composite oxide film is used, where the tin oxide content is 10% by mass. This indium-tin composite oxide film is formed on a glass substrate with dimensions of 232 mm × 151 mm by sputtering, and has a thickness of 20 nm, on the side of the glass substrate with the indium-tin composite oxide film, hereinafter also referred to as ITO glass, of the transparent conductive film A, epoxy resins as point spacers are arranged in a square lattice with a 4 mm pitch, with a length of 60 μm × a width of 60 μm × a height of 5 μm, Next, starting from any one of the four corners of the ITO glass, a double-sided tape with a thickness of 105 μm and a width of 6 mm is pasted on the side of the transparent conductive film A of the ITO glass so as to be able to form a rectangle of 190 mm × 135 mm, Next, on the double-sided tape pasted on the ITO glass, the transparent conductive film B side of the transparent conductive film is pasted, and laminated so that the transparent conductive film A and the transparent conductive film B are opposed to each other, At this time, one short side of the transparent conductive film protrudes from the ITO glass, Next, a tester is connected to the ITO glass and the transparent conductive film, Next, a load is applied from the transparent conductive film side using a polyoxymethylene pen with a tip shape of 0.8 mmR, and the load value when the resistance value measured by the tester is stable is set as the input start load, The position where the load is applied by the pen is the central area surrounded by four point spacers, and the average value of the input start loads at 3 points is calculated.

2. The transparent conductive film according to claim 1, wherein, the bending resistance of the following film bending resistance test is 0.23 N·cm or more and 0.90 N·cm or less, Furthermore, the following average maximum peak height of the conductive surface of the transparent conductive film satisfies the following formula (2-1) and formula (2-2), in the film bending resistance test method, a test piece of 20 mm × 250 mm is collected from the transparent conductive film, and the test piece is placed on a smooth horizontal table with the transparent conductive layer facing up. At this time, only the 20 mm × 20 mm part of the test piece is placed on the horizontal table, and the 20 mm × 230 mm part is placed so as to protrude outside the horizontal table. In addition, a heavy object is placed on the 20 mm × 20 mm part of the test piece. At this time, the weight and size of the heavy object are selected so that no gap is generated between the test piece and the horizontal table, Next, the difference in height between the horizontal table and the front end of the film, hereinafter also referred to as δ, is read by a scale, and then the numerical value is substituted into the following formula (1) to calculate the bending resistance, (g × a × b × L 4 ) ÷ 8δ (N·cm) Equation (1) where, g = acceleration due to gravity, a = length of the short side of the test piece, b = specific gravity of the test piece, L = length of the test piece, δ = difference in height between the horizontal platform and the front end of the thin film, In the average maximum peak height evaluation, the average maximum peak height is the average of the maximum peak heights at 5 points. In the method of selecting 5 points, first, arbitrarily select 1 point A. Next, with respect to A, select 1 point each at 1 cm upstream and downstream in the machine direction (MD) of the long side of the thin film, for a total of 2 points. Next, with respect to A, select 1 point each at 1 cm to the left and right in the transverse direction (TD) of the width of the thin film, for a total of 2 points. The maximum peak height is specified by ISO 25178 and obtained by using a three-dimensional surface shape measuring device, Bert Scan. The three-dimensional surface shape measuring device, Bert Scan, is manufactured by Rhomboid Systems Co., Ltd., model R5500H-M100, where the measurement conditions are wave mode, the measurement wavelength is 560 nm, and the objective lens is 10 times magnification. In addition, values less than 1 nm are rounded off. Average maximum peak height (μm) ≥ 4.7 × Flexural property - 1.8 Equation (2-1) 0.005 (μm) ≤ Average maximum peak height (μm) ≤ 12.000 (μm) Equation (2-2).

3. The transparent conductive film according to claim 2, wherein, the maximum value of the maximum peak height in the average maximum peak height evaluation exceeds 1.0 times and is 1.4 times or less of the average maximum peak height, and the minimum value of the maximum peak height in the average maximum peak height evaluation is 0.6 times or more and 1.0 times or less of the average maximum peak height.

4. The transparent conductive film according to any one of claims 1 to 3, wherein, the thickness of the transparent conductive film is 10 nm or more and 100 nm or less.

5. The transparent conductive film according to any one of claims 1 to 3, wherein, the concentration of tin oxide contained in the transparent conductive film is 0.5 mass% or more and 40 mass% or less.

6. The transparent conductive film according to any one of claims 1 to 3, wherein, a curable resin layer is provided between the transparent conductive film and the transparent plastic film substrate, and a functional layer is further provided on the side of the transparent plastic film substrate opposite to the transparent conductive film.

7. The transparent conductive film according to any one of claims 1 to 3, wherein, an easy-bonding layer is provided on at least one side of the transparent plastic film substrate.

8. The transparent conductive film according to claim 6, wherein, the easy-bonding layer is disposed at least at one of the positions between the transparent plastic film substrate and the curable resin layer, or between the transparent plastic film substrate and the functional layer.

9. The transparent conductive film according to any one of claims 1 to 3, wherein, the on-resistance of the transparent conductive film of the transparent conductive film obtained by the following pen-sliding durability test is 10 kΩ or less, In the pen-sliding durability test, A transparent conductive film is used as one panel, and a transparent conductive film made of an indium-tin composite oxide film is used as the other panel. The content of tin oxide is 10% by mass. The indium-tin composite oxide film is formed on a glass substrate by sputtering and has a thickness of 20 nm. The two panels are arranged with epoxy beads having a diameter of 30 μm in between so that the transparent conductive films face each other to fabricate a touch panel. Next, a load of 2.5 N is applied to a polyacetal pen with a tip shape of 0.8 mmR, and a linear sliding test of 50,000 reciprocations is performed on the touch panel. At this time, the sliding distance is 30 mm and the sliding speed is 180 mm / second. After this sliding durability test, the conduction resistance when pressing the sliding portion with a pen load of 0.8 N, that is, the resistance value when the movable electrode as the thin film electrode contacts the fixed electrode, is measured.

10. The transparent conductive film according to any one of claims 1 to 3, wherein in the adhesion test based on JIS K5600-5-6:1999 on the surface of the transparent conductive film, the residual area ratio of the transparent conductive film is 95% or more.

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