Transparent Conductive Film

Abstract

Provided is a transparent conductive film having excellent lightsome input, input stability, and clarity.　The transparent conductive film, in which a transparent conductive film of an indium-tin composite oxide is laminated on at least one surface of a transparent plastic film substrate, has: an input starting load of 3-15 g; a voltage loss time of 0.00-0.40 milliseconds; and a total sum of five types of transmission image clarity of 400-500%, as measured using each of five types of optical combs which have a 0.125 mm width, 0.25 mm width, 0.5 mm width, 1 mm width, and 2 mm width, respectively.

Description

[Technical Field]

[0001] The present invention relates to a transparent conductive film in which a transparent conductive film of indium-tin composite oxide is laminated on a transparent plastic film substrate. [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 made of a glass or plastic substrate coated with a transparent conductive thin film with a movable electrode (called a film electrode) made of a plastic film coated with a transparent conductive thin film, and are used by overlaying them on top of the display. When the film electrode is pressed with a finger or pen (called input), the transparent conductive thin films of the fixed electrode and the film electrode come into contact, and the input position is recognized.

[0004] Patent Document 1 discloses a transparent conductive laminate for touch panels, which has a transparent conductive film made mainly of substantially crystalline indium oxide laminated on at least one surface of a polymer film. It is said that crystallizing the indium oxide improves writing durability. [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] Touch panels are required to have properties (pen sliding durability) that prevent cracks, peeling, and wear on the transparent conductive film even when continuous input is made with a pen. Touch panels also require light input capabilities, which means that when inputting data onto a resistive touch panel with a pen or finger, the data can be input even with a light touch.

[0007] Furthermore, touch panels are required to have excellent input stability, meaning that input to the touch panel remains stable from the time the touch panel is touched with a pen or other object until it is released. For example, excellent features are required, such as reducing the blurring that can occur when continuously entering characters (stenographic stability) and preventing the brushing of characters (brushing stability). Clearness of the touch panel is also desirable. High clarity of the touch panel has the advantage of making images appear sharper and creating a sense of luxury by making the touch panel appear clearly black when the display is turned off. The technology of Patent Document 1 could not improve pen sliding durability unless indium oxide was crystallized. Furthermore, conventional transparent conductive films including those of Patent Document 1 were insufficient in terms of light input performance, input stability (shorthand stability, sweep stability), clarity, etc.

[0008] Therefore, an object of the present invention is to provide a transparent conductive film that is excellent in light input performance, input stability, and clarity. Another preferred object of the present invention is to provide a transparent conductive film that also has pen sliding durability. Another preferred object of the present invention is to provide a transparent conductive film that also has the ability to prevent false responses. [Means for solving the problem]

[0009] 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 having a transparent conductive film of indium-tin composite oxide laminated on at least one surface of a transparent plastic film substrate, The input start load determined by test method 1 is 3g or more and 15g or less, The voltage loss time determined by test method 2 is between 0.00 milliseconds and 0.40 milliseconds, A transparent conductive film having a total transmitted image clarity of 400 to 500% for five different types of measured in accordance with JIS K7374 using an image clarity measuring device using five optical combs with widths of 0.125 mm, 0.25 mm, 0.5 mm, 1 mm, and 2 mm. [Test Method 1] A 20-nm-thick indium-tin composite oxide conductive film (tin oxide content: 10% by mass) was formed on one side of a glass substrate. Dot spacers (60 μm long x 60 μm wide x 5 μm high) were formed on the surface of this thin film in a square lattice pattern with a 4-mm pitch to create a panel board. A 105-μm-thick, adhesive rectangular frame with an inner circumference of 190 mm x 135 mm was sandwiched between the conductive film side of this panel board, and a transparent conductive film was placed on top of it so that the conductive films faced each other to create an evaluation panel. From the transparent conductive film side of this evaluation panel, pressure was applied to the center of the four-point grid of dot spacers with a hemispherical polyacetal pen with a 0.8 mm radius. The pressure at which the resistance began to stabilize was defined as the input starting load. [Test Method 2] The evaluation panel was connected to a 6V constant voltage power supply, and a pen with a hemispherical tip of 0.8mm radius was used to press the center of the four-point grid of the dot spacer from the transparent conductive film side with a load of 50gf at intervals of 5 times per second. The time when the pen began to separate from the transparent conductive film and the voltage decreased from 6V was taken as the starting point, and the time until the voltage reached 5V was measured and recorded as the voltage loss time. [2] The film bending resistance (BR) determined by Test Method 3 is 0.23 N·cm or more and 0.90 N·cm or less, The average of the maximum peak heights Sp of the conductive surface (AVSp) obtained by Test Method 4 satisfies the following formulas (2-1) and (2-2), The contact area ratio (CA) calculated by Test Method 5 satisfies the following formula (2-3), The transparent conductive film according to [1], having an arithmetic mean height Sa (in accordance with ISO 25178) of 1 to 55 nm. AVSp≧4.7×BR-1.8…Formula (2-1) 0.005≦AVSp≦12.000 …Formula (2-2) CA≧32.6×BR+17.2 …Formula (2-3) (Wherein, BR is the film bending resistance (N·cm), AVSp is the average maximum peak height (μm), and CA is the contact area ratio (%).) [Test Method 3] A 20mm x 250mm transparent conductive film test piece is placed on a horizontal table with the transparent conductive film facing up, and the test piece is allowed to protrude 230mm from the edge of the table, and the bending resistance (BR) is determined based on the following formula. Bending resistance (BR(N cm))=g×a×b×L 4 / (8×δ×10 11 ) (where a is 9.81 (gravitational acceleration; m / s 2 ), and b is the specific gravity of the test piece (g / cm 3 ), L is 230 (the length of the long side of the test piece outside the horizontal table; mm), and δ is the difference in height between the tip of the test piece and the height of the table (cm). [Test Method 4] A total of five measurement points are determined on the conductive surface of the transparent conductive film: three points at 1 cm intervals in the MD direction, and two points symmetrically from the center in the TD direction. The maximum peak height Sp (in accordance with ISO 25178) due to surface roughness is measured at each point, and the average value is taken as the average maximum peak height (AVSp) (μm). [Test Method 5] The average height Rc (μm), maximum peak height Rp (μm), and average length Rsm (μm) of the line roughness of the conductive surface of the transparent conductive film are measured, and the arithmetic mean height Ra (μm) of the line roughness is measured at locations where at least one of formulas (X1) and (X2) and formula (X3) are satisfied. The average height Rc (μm), maximum peak height Rp (μm), average length Rsm (μm), and arithmetic mean height Ra (μm) are determined using a 3D surface profiler, VertScan (R5500H-M100, manufactured by Ryoka Systems Co., Ltd. (measurement conditions: wave mode, measurement wavelength 560 nm, objective lens 50x). The determination of the maximum peak height Rp (μm), average length Rsm (μm), and arithmetic mean height Ra (μm) is in accordance with the provisions of JIS B 0601-2001. The measurement length of the arithmetic mean height Ra (μm) is 100 μm or more and 200 μm or less. Rp-Rc-Ra≦0.20…Formula (X1) (Rp-Rc) / Ra≦5.0…Formula (X2) Rsm≦30…Formula (X3) The objective lens of the 3D surface shape measuring device, Bart Scan, was changed to 10x, and the particle analysis in the measuring device was used to calculate the "arithmetic mean height Ra (μm) - 15 × 10 -3 The height where "(μm) - average height Rc (μm)" is used as the threshold value, and the sample is sliced ​​in the planar direction to calculate the sum of the cross-sectional areas. The sum of the cross-sectional areas is divided by the area of ​​the measurement field of view, and the result multiplied by 100 is the contact area ratio (CA) (%). [3] The maximum value MXSp of the maximum peak heights Sp determined by the test method 4 is more than 1.0 times and 1.4 times or less of the average maximum peak height AVSp, and The transparent conductive film according to [2], wherein the minimum value MNSp of the maximum peak heights Sp determined by the test method 4 is 0.6 to 1.0 times the average maximum peak height AVSp. [4] The transparent conductive film according to any one of [1] to [3], wherein the transparent conductive film has a thickness of 10 nm or more and 100 nm or less. [5] The transparent conductive film according to any one of [1] to [4], wherein the concentration of tin oxide contained in the transparent conductive film is 0.5% by mass or more and 40% by mass or less. [6] A curable resin layer is provided between the transparent conductive film and the transparent plastic film substrate, The transparent conductive film according to any one of [1] to [5], further comprising a functional layer on the opposite side of the transparent plastic substrate from the transparent conductive film. [7] The transparent conductive film according to any one of [1] to [6], which has an easy-adhesion layer on at least one side of the transparent plastic film substrate. [8] The transparent conductive film according to [7], wherein the easy-adhesion layer is disposed at least one position between the transparent plastic film substrate and the curable resin layer or between the transparent plastic substrate and the functional layer. [9] The transparent conductive film according to any one of [1] to [8], which has an ON resistance determined by Test Method 6 of 10 kΩ or less. [Test Method 6] An evaluation panel was created by stacking a panel board with a 20 nm thick indium-tin composite oxide conductive film (tin oxide content: 10% by mass) formed on one side of a glass substrate and a transparent conductive film, with the conductive films facing each other. The transparent conductive film side of this evaluation panel was slid with a hemispherical polyacetal pen with a 0.8 mm radius tip while applying a load of 2.5 N (50,000 reciprocating strokes, sliding distance: 30 mm, sliding speed: 180 mm / sec). After sliding, the center of the sliding area was pressed with a pen load of 0.8 N to establish an electrical connection, and the resistance (ON resistance) was measured.

[10] The transparent conductive film according to any one of [1] to [9], wherein the remaining area ratio of the transparent conductive film on the surface of the transparent conductive film is 95% or more in an adhesion test in accordance with JIS K5600-5-6:1999. [Effects of the Invention]

[0010] According to the present invention, a transparent conductive film can be provided that exhibits excellent clarity, input stability, and light input performance. Furthermore, according to the present invention, a transparent conductive film can be provided that, when desired, further exhibits pen sliding durability and resistance to erroneous responses. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic side view showing an example of the transparent conductive film of the present invention. [Figure 2] FIG. 2 is a schematic side view showing another example of the transparent conductive film of the present invention. [Figure 3] FIG. 3 is a schematic side view showing still another example of the transparent conductive film of the present invention. [Figure 4] FIG. 4 is a schematic side view showing another example of the transparent conductive film of the present invention. [Figure 5] FIG. 5 is a conceptual diagram showing the relationship between voltage and time in one embodiment of the present invention. [Figure 6] FIG. 6 is a schematic diagram of an apparatus showing an example of the film forming method of the present invention. [Figure 7] FIG. 7 is a schematic plan view for explaining the input start load measuring method according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] 1. Transparent conductive film The transparent conductive film of the present invention comprises a transparent plastic film substrate and a transparent conductive film of indium-tin composite oxide laminated on at least one surface thereof. By providing a transparent conductive film on the surface, the film can be widely used in electrical and electronic applications, utilizing its electrical conductivity, such as flat panel displays such as liquid crystal displays and electroluminescence (EL) displays, and transparent electrodes for touch panels. The specific layer structure of the transparent conductive film can be appropriately determined, and examples thereof include the structures shown in the schematic side views of Figures 1, 2, 3, and 4.

[0013] The transparent conductive film of FIG. 1 has a transparent conductive film 5 formed on one side of a transparent plastic film substrate 7 via a curable resin layer 6, and a functional layer 8 formed on the opposite side of the transparent plastic film substrate 7. Forming the curable resin layer 6 between the transparent conductive film 5 and the transparent plastic film substrate 7 can block the precipitation of monomers and oligomers from the transparent plastic film substrate 7 onto the transparent conductive film 5. The transparent conductive film of the present invention has improved input strength characteristics (e.g., prevention of erroneous responses, quick input), input stability, and clarity by controlling the input start load, voltage loss time, and transmitted image clarity, as described below. Blocking oligomer precipitation further improves the input strength characteristics (e.g., prevention of erroneous responses, quick input), input stability, and clarity. Furthermore, by preventing the precipitation of monomers and oligomers using the curable resin layer 6 and / or functional layer 8, the transparency (clarity) and visibility of the transparent conductive film can be further improved. Furthermore, the presence of the curable resin layer 6 and / or functional layer 8 allows the bending resistance of the transparent conductive film, as described below, to be adjusted. Depending on the rigidity of the transparent plastic film substrate, the curable resin layer 6 and / or the functional layer 8 may not necessarily be required.

[0014] In one embodiment, the transparent conductive film of the present invention has an easy-adhesion layer laminated on at least one side of the transparent plastic film substrate. For example, as shown in FIG. 2, the curable resin layer 6 and the transparent plastic film substrate 7 may be bonded together with an easy-adhesion layer 9. As shown in FIG. 3, the functional layer 8 and the transparent plastic film substrate 7 may be bonded together with an easy-adhesion layer 9. As shown in FIG. 4, the curable resin layer 6 and the functional layer 8 may each be bonded together with the transparent plastic film substrate 7 with an easy-adhesion layer 9. The presence of the easy-adhesion layer 9 can more effectively prevent the curable resin layer 6 and / or the functional layer 8 from peeling off from the transparent plastic film substrate 7 due to external force.

[0015] The transparent conductive film of the present invention is characterized in that the input start load determined by Test Method 1 is 3 g or more and 15 g or less (Feature 1). By setting the input start load to a predetermined value or less, it is possible to improve the smoothness of input. By setting the input start load to a predetermined value or more, it is possible to improve the prevention of erroneous responses of the touch panel. The input start load may be any one of 4 g or more, 5 g or more, or 6 g or more, and may be any one of 14 g or less, 13 g or less, or 12 g or less.

[0016] [Test Method 1] A 20 nm thick indium-tin composite oxide conductive film (tin oxide content: 10% by mass) was formed on one side of a glass substrate. Dot spacers (60 μm length x 60 μm width x 5 μm height) were formed on the surface of the thin film in a square lattice pattern with a 4 mm pitch to create a panel board. A 105 μm thick, adhesive rectangular frame with an inner circumference of 190 mm x 135 mm was sandwiched between the conductive film side of this panel board, and a transparent conductive film was placed on top of the panel board so that the conductive films faced each other to create an evaluation panel. From the transparent conductive film side of the evaluation panel, pressure was applied to the center of the four-point grid of dot spacers with a hemispherical polyacetal pen with a 0.8 mm radius tip. The pressure at which the resistance value began to stabilize was defined as the input initial load. Here, "stable resistance value" refers to a state in which the resistance value fluctuates within a ±5% range.

[0017] The transparent conductive film also has a feature (Feature 2) in that the voltage loss time determined by Test Method 2 is between 0.00 milliseconds and 0.40 milliseconds. By keeping the voltage loss time within a specified range, the electrically stable contact time can be extended. By setting the input start load below a specified value, smooth input can be improved, and by keeping the voltage loss time within a specified range, input stability, such as sweeping stability and shorthand stability, can be improved. While the reason for this input stability effect should not be interpreted as being limited to a specific theory, it is believed that the electrically stable contact time can be extended and electrically unstable contact conditions can be further reduced. As a result, the unstable input time is shortened, preventing, for example, blurring of characters when writing consecutive characters and reducing blurring of characters during shorthand. Furthermore, this can solve the problem of characters appearing blurred or not appearing on a touch panel when sweeping characters. This allows for vivid drawing of desired characters and pictures on a resistive touch panel. For example, it can also express brush strokes of characters as if they were written with a calligraphy brush.

[0018] The voltage loss time is preferably 0.39 milliseconds or less, more preferably 0.35 milliseconds or less, and even more preferably 0.30 milliseconds or less, and the shorter the better. The voltage loss time may be 0.01 milliseconds or more, for example, 0.02 milliseconds or more.

[0019] [Test Method 2] The evaluation panel was connected to a 6V constant-voltage power supply, and a pen with a hemispherical tip and a radius of 0.8mm was used to press the center of the four-point grid of the dot spacer from the transparent conductive film side with a load of 50gf at intervals of 5 times per second. The time when the pen began to separate from the transparent conductive film and the voltage decreased from 6V was measured, and the time until the voltage reached 5V was measured was determined as the voltage loss time. For example, Figure 5 is a conceptual diagram showing the relationship between voltage and time in one embodiment of the present invention, where the horizontal axis 13 is the time axis, the vertical axis 14 is the voltage, and the voltage loss time 15 is measured.

[0020] The transparent conductive film is also characterized in that the sum of five types of transmitted image clarity measured in accordance with JIS K7374 using an image clarity measuring device using five types of optical combs with widths of 0.125 mm, 0.25 mm, 0.5 mm, 1 mm, and 2 mm is 400 to 500% (Feature 4). Having the sum of transmitted image clarity within the specified range results in excellent clarity of the touch panel. The sum of transmitted image clarity is preferably 430 to 500%, more preferably 450 to 500%, and even more preferably 460 to 500%, with the larger the sum, the better.

[0021] The transparent conductive film preferably has an ON resistance of 10 kΩ or less as determined by Test Method 6 (Feature 3). The smaller the ON resistance, the higher the pen sliding durability. The ON resistance is preferably 8 kΩ or less, more preferably 5 kΩ or less, even more preferably 3 kΩ or less, and particularly preferably 1.0 kΩ or less. The ON resistance may be, for example, 0.1 kΩ or more, 2 kΩ or more, or 4 kΩ or more. [Test Method 6] An evaluation panel was created by stacking a panel board with a 20 nm thick indium-tin composite oxide conductive film (tin oxide content: 10% by mass) formed on one side of a glass substrate and a transparent conductive film, with the conductive films facing each other. The transparent conductive film side of this evaluation panel was slid with a hemispherical polyacetal pen with a 0.8 mm radius tip while applying a load of 2.5 N (50,000 reciprocating strokes, sliding distance: 30 mm, sliding speed: 180 mm / sec). After sliding, the center of the sliding area was pressed with a pen load of 0.8 N to establish an electrical connection, and the resistance (ON resistance) was measured. Transparent conductive films that have Feature 1 (input start load), Feature 2 (voltage loss time), and Feature 4 (clarity) are extremely useful for applications such as resistive touch panels.

[0022] The transparent conductive film preferably has a film bending resistance (BR) of 0.23 N·cm or more and 0.90 N·cm or less, as determined by Test Method 3. By reducing the film bending resistance (BR) to a predetermined value or less, the ON resistance can be reduced to a predetermined value or less. Reducing the film bending resistance (BR) is also useful for reducing the input initial load. The film bending resistance (BR) is more preferably 0.27 N·cm or more, and even more preferably 0.30 N·cm or more. It is also more preferably 0.80 N·cm or less, even more preferably 0.70 N·cm or less, and particularly preferably 0.60 N·cm or less.

[0023] [Test Method 3] A 20mm x 250mm transparent conductive film test piece is placed on a horizontal table with the transparent conductive film facing up, and the test piece is allowed to protrude 230mm from the edge of the table, and the bending resistance (BR) is determined based on the following formula. Note that the bending resistance value changes if the transparent conductive film is placed facing down, so care must be taken. Bending resistance (BR(N cm))=g×a×b×L 4 / (8×δ×10 11 ) (where a is 9.81 (gravitational acceleration; m / s 2 ), and b is the specific gravity of the test piece (g / cm 3 ), L is 230 (the length of the long side of the test piece outside the horizontal table; mm), and δ is the difference in height between the tip of the test piece and the height of the table (cm).

[0024] The transparent conductive film preferably has an average maximum peak height Sp (AVSp) of the conductive surface determined by Test Method 4 that satisfies the following formula (2-1): The input initial load is governed by two parameters, the film bending resistance (BR) and the average maximum peak height (AVSp), and by setting the average maximum peak height (AVSp) to a predetermined value or more determined from the film bending resistance (BR), the input initial load can be set to a predetermined value or less. AVSp≧4.7×BR-1.8…Formula (2-1) (Wherein, BR is the film bending resistance (N·cm), and AVSp is the average maximum peak height (μm)) [Test Method 4] A total of five measurement points are determined on the conductive surface of the transparent conductive film: three points at 1 cm intervals in the MD direction, and two points symmetrically from the center in the TD direction. The maximum peak height Sp (in accordance with ISO 25178) due to surface roughness is measured at each point, and the average value is taken as the average maximum peak height (AVSp) (μm).

[0025] The relationship of the inequality sign on the right side of formula (2-1) is more preferably AVSp ≧ 4.7 × BR − 1.7, even more preferably AVSp ≧ 4.7 × BR − 1.6, even more preferably AVSp ≧ 4.7 × BR − 1.5, and particularly preferably AVSp ≧ 4.7 × BR − 1.4. Although the upper limit of AVSp is not limited by its relationship with BR, the effects of the present invention can be achieved even if, for example, AVSp ≦ 4.7 × BR + 10 or AVSp ≦ 4.7 × BR + 3.

[0026] The transparent conductive film preferably has an average maximum peak height (AVSp) that satisfies the following formula (2-2). When the average maximum peak height (AVSp) is a predetermined value or more, the transparent conductive film can be wound into a roll without any problems. The average maximum peak height (AVSp) is more preferably 0.010 (μm) or more, and even more preferably 0.020 (μm) or more. Furthermore, by setting the average maximum peak height (AVSp) to a predetermined value or less, unintended electrical contact can be more appropriately prevented. The average maximum peak height (AVSp) is more preferably 10,000 (μm) or less, and even more preferably 5,000 (μm) or less. 0.005≦AVSp≦12.000 …Formula (2-2) (wherein AVSp is the average maximum peak height (μm))

[0027] The transparent conductive film preferably has a contact area ratio (CA) determined by Test Method 5 that satisfies the following formula (2-3). By ensuring that the contact area ratio (CA) is equal to or greater than a predetermined value, the voltage loss time can be reduced to a predetermined value or less. This is thought to be because the greater the contact area ratio (CA), the more stable the electrical contact between the conductive layers. This is thought to increase the time it takes for a pen, finger, or other object to separate from the transparent conductive film of a resistive touch panel before the contact area becomes unstable. Furthermore, the reason why the contact area ratio (CA) increases with increasing bending resistance (BR) in formula (2-3) is that the greater the bending resistance (BR), the faster a pen, finger, or other object separates from the transparent conductive film of a resistive touch panel, making it necessary to use a transparent conductive film with a high contact area ratio (CA). CA≧32.6×BR+17.2 …Formula (2-3) (Wherein, BR is the film bending resistance (N·cm), and CA is the contact area ratio (%).)

[0028] [Test Method 5] The average height Rc (μm), maximum peak height Rp (μm), and average length Rsm (μm) of the line roughness of the conductive surface of the transparent conductive film are measured, and the arithmetic mean height Ra (μm) of the line roughness is measured at locations where at least one of formulas (X1) and (X2) and formula (X3) are satisfied. The average height Rc (μm), maximum peak height Rp (μm), average length Rsm (μm), and arithmetic mean height Ra (μm) are determined using a 3D surface profiler, VertScan (R5500H-M100, manufactured by Ryoka Systems Co., Ltd. (measurement conditions: wave mode, measurement wavelength 560 nm, objective lens 50x). The determination of the maximum peak height Rp (μm), average length Rsm (μm), and arithmetic mean height Ra (μm) is in accordance with the provisions of JIS B 0601-2001. The measurement length of the arithmetic mean height Ra (μm) is 100 μm or more and 200 μm or less. Rp-Rc-Ra≦0.20…Formula (X1) (Rp-Rc) / Ra≦5.0…Formula (X2) Rsm≦30…Formula (X3) The objective lens of the 3D surface shape measuring device, Bart Scan, was changed to 10x, and the particle analysis in the measuring device was used to calculate the arithmetic mean height Ra (μm) -15 × 10 from the average surface (a 3D representation of the average line). -3 The height where "(μm) - average height Rc (μm)" is used as the threshold value, and the sample is sliced ​​in the planar direction to calculate the sum of the cross-sectional areas. The sum of the cross-sectional areas is divided by the area of ​​the measurement field of view, and the result multiplied by 100 is the contact area ratio (CA) (%).

[0029] In the test method 5, "arithmetic mean height Ra (μm) - 15 × 10 -3 The reason for considering "(μm)" is as follows: Most of the transparent conductive film in contact with the transparent conductive glass is a protrusion of the average height of the transparent conductive film. Since it is difficult to accurately calculate the contact area with protrusions of this average height, a height slightly smaller than the average protrusion height (= 15 x 10 times the average height of the transparent conductive film) was used as an alternative indicator. -3 The cross-sectional area of ​​the transparent conductive film on the transparent conductive film side at a height (height lower than the mean plane by an average height Rc (μm)) was used (note that this height is based on the point that is lower by an average height Rc (μm) from the mean plane). Here, if the arithmetic mean roughness Ra according to JIS B 0601-2001 is used as the average protrusion height of the transparent conductive film, this is not preferable because the arithmetic mean roughness Ra will be larger than the actual average protrusion height of the transparent conductive film due to the influence of the few but very tall coarse protrusions on the transparent conductive film side of the transparent conductive film. Therefore, in order to eliminate the influence of the coarse protrusions, the arithmetic mean height Ra (μm) was measured at locations that satisfied at least one of formulas (X1) and (X2) and formula (X3).

[0030] The relationship between CA and BR represented by formula (2-3) is more preferably CA ≥ 32.6 × BR + 17.5, even more preferably CA ≥ 32.6 × BR + 18.0, even more preferably CA ≥ 32.6 × BR + 19.0, and particularly preferably CA ≥ 32.6 × BR + 30. There is no particular upper limit to CA in relation to BR, but the effects of the present invention can be achieved even if, for example, CA ≤ 32.6 × BR + 85 or CA ≤ 32.6 × BR + 65.

[0031] The transparent conductive film preferably has an arithmetic mean height Sa (in accordance with ISO 25178) of 1 to 55 nm. By setting the arithmetic mean height Sa to a predetermined value or less, the size and number of surface protrusions become smaller, thereby reducing light scattering and increasing the total clarity of transmitted images, resulting in good clarity. By setting the arithmetic mean height Sa to a predetermined value or more, it is possible to achieve a size and number of surface protrusions that are effective for maintaining film winding properties. The arithmetic mean height Sa is more preferably 3 nm or more, even more preferably 5 nm or more, more preferably 50 nm or less, and even more preferably 45 nm or less.

[0032] The transparent conductive film preferably has a maximum value MXSp of maximum peak height Sp determined by Test Method 4 that is more than 1.0 times but not more than 1.4 times the average maximum peak height AVSp. By setting the maximum value MXSp to a predetermined value or less, the in-plane distribution of tall protrusions on the transparent conductive film becomes uniform, which is preferable because it enables touch panel input operations with the same input initiation load at any location. A maximum value MXSp of 1.3 times or less is more preferable, and a maximum value MXSp of 1.2 times or less is even more preferable.

[0033] The transparent conductive film preferably has a minimum value MNSp of the maximum peak height Sp determined by Test Method 4 that is 0.6 to 1.0 times the average maximum peak height AVSp. By setting the minimum value MNSp to a predetermined value or more, the in-plane distribution of tall protrusions on the transparent conductive film becomes uniform, which is preferable because it enables touch panel input with the same input initiation load at any location. The minimum value MNSp is more preferably 0.7 times or more, and even more preferably 0.8 times or more. Furthermore, by setting both the maximum value MXSp and the minimum value MNSp within a predetermined range, the variation in the input start load can be reduced to less than ±5%.

[0034] The total light transmittance of the transparent conductive film is, for example, 70% or more and 95% or less, preferably 80% or more and 95% or less, and more preferably 85% or more and 90% or less.

[0035] 2.Transparent conductive film The transparent conductive film is made of an indium-tin composite oxide. The tin oxide concentration in the transparent conductive film is preferably 0.5% by mass or more and 40% by mass or less. A tin oxide content of 0.5% by mass or more is preferable because the surface resistance of the transparent conductive film is at a practical level. Furthermore, by setting the tin oxide concentration to 40% by mass or less, the tin oxide concentration in the transparent conductive film of the transparent conductive film can be made closer to the tin oxide concentration in the transparent conductive glass substrate for touch panels. The closer the tin oxide concentrations of the transparent conductive film and the transparent conductive film of the glass substrate, the easier the electrical contact between the two transparent conductive films becomes, resulting in better input strength characteristics (e.g., prevention of false responses, smooth input performance) and input stability. The tin oxide concentration in the transparent conductive film is more preferably 25% by mass or less, even more preferably 20% by mass or less, particularly preferably 18% by mass or less, more preferably 1% by mass or more, and even more preferably 2% by mass or more.

[0036] The tin oxide concentration in a transparent conductive glass substrate for a touch panel is generally 10% by mass. The difference between the tin oxide concentration of the transparent conductive film and the tin oxide concentration of the glass substrate is, for example, 30% by mass or less, preferably 20% by mass or less, and more preferably 10% by mass or less.

[0037] The crystallinity of the transparent conductive film may be from 0% to 100%, preferably from 10% to 100%, and more preferably from 50% to 100%. The higher the crystallinity, the better the pen sliding properties.

[0038] The surface resistance of the transparent conductive film is, for example, 50 Ω / □ to 900 Ω / □, preferably 50 Ω / □ to 700 Ω / □, and more preferably 70 Ω / □ to 500 Ω / □.

[0039] The thickness of the transparent conductive film is preferably 10 nm or more and 100 nm or less. When the thickness of the transparent conductive film is 10 nm or more, the entire transparent conductive film adheres to the transparent plastic film substrate or the cured resin layer described below, the film quality of the transparent conductive film is stable, and the surface resistance value tends to be stable and within a preferred range. This is also effective in reducing the ON resistance determined by Test Method 6. The thickness of the transparent conductive film is more preferably 13 nm or more, and even more preferably 16 nm or more. Furthermore, when the thickness of the transparent conductive film is 100 nm or less, the crystal grain size and degree of crystallinity of the transparent conductive film become appropriate, and the total light transmittance reaches a practical level, which is preferable. The thickness is more preferably 50 nm or less, even more preferably 30 nm or less, and particularly preferably 25 nm or less.

[0040] In an adhesion test on the surface of the transparent conductive film in accordance with JIS K5600-5-6:1999, the remaining area ratio of the transparent conductive film is preferably 95% or more, more preferably 99% or more, and particularly preferably 99.5% or more. When the remaining area ratio of the transparent conductive film in the adhesion test is within the above range, the transparent conductive film adheres well to layers in contact with the transparent conductive film, such as the transparent plastic film substrate and the cured resin layer described below, and cracking, peeling, wear, etc. of the transparent conductive film are suppressed even when continuous input is made to the touch panel with a pen, and further cracking, peeling, etc. of the transparent conductive film are suppressed even when a force stronger than expected in normal use is applied, which is preferable.

[0041] The method for forming the transparent conductive film is not particularly limited, but a preferred method is, for example, a method in which a transparent conductive film of indium-tin composite oxide is formed by sputtering on at least one surface of a transparent plastic film substrate 7 (hereinafter referred to as the film to be treated) on the surface of which a cured resin layer 6 may be formed. In order to produce a transparent conductive film with high productivity, it is preferable to use a so-called roll-type sputtering device in which the film to be treated is supplied from a film roll and, after film formation, is wound up into the shape of a film roll.

[0042] Figure 6 is a schematic diagram of an example of a film formation method in a roll-type sputtering device. In this illustrated example, a film 1 to be treated, fed from a film roll (not shown), runs while partially contacting the surface of a center roll 2. An indium-tin sputtering target 4 is placed in a chimney 3 having an opening facing the contact point between the film 1 to be treated and the center roll 2, and a thin film of indium-tin composite oxide is deposited and laminated on the surface of the film 1 to be treated running on the center roll 2. The temperature of the center roll 2 can be controlled by a temperature regulator (not shown).

[0043] As the target, it is preferable to use a sintered target of indium-tin composite oxide. In order to improve production efficiency, a plurality of sintered targets of indium-tin composite oxide may be placed in the direction of film flow.

[0044] To form the film-forming atmosphere, it is preferable to flow oxygen gas, an inert gas (such as argon gas), or the like, using a mass flow controller as needed. Adding oxygen gas can improve the surface resistance and total light transmittance of the transparent conductive film. The flow rate ratio (volume ratio) of oxygen gas to the inert gas (oxygen gas / inert gas) is, for example, 0.005 or more, preferably 0.010 or more, more preferably 0.020 or more, and for example, 0.15 or less, preferably 0.1 or less, more preferably 0.07 or less, and even more preferably 0.05 or less. Furthermore, a hydrogen-atom-containing gas (hydrogen, ammonia, a hydrogen + argon mixed gas, or the like, is not particularly limited as long as it contains hydrogen atoms, but water is excluded) may be flowed into the film-forming atmosphere as needed, using a mass flow controller.

[0045] The median value (the midpoint between the maximum and minimum values) of the ratio of water pressure to inert gas in the film formation atmosphere (water pressure / inert gas partial pressure) is, for example, 7.00 x 10 -3 Less than or equal to 5.00 x 10 -3 or less, more preferably 3.00 x 10 -3 The lower the water content in the film-forming atmosphere, the more appropriate the quality of the transparent conductive film, the easier it is to achieve a desirable surface resistance value, and the more reliable the crystallization. While it is possible to control the moisture content using the ultimate vacuum as a guide, measuring the moisture content (water pressure) during film formation is preferable for two reasons. First, when a film is formed on a plastic film by sputtering, the film is heated and moisture is released from the film. The ultimate vacuum does not reflect the effect of this released moisture. Second, the ultimate vacuum does not reflect the effect of moisture in the center of the roll when the film is formed after being unwound from the film roll. When a film roll is held in a vacuum chamber, water easily escapes from the outer layer of the roll, but water does not escape from the inner layer of the roll. While the film is stopped when measuring the ultimate vacuum, the film continues to move during film formation, unwinding the inner layer of the film roll, which contains a large amount of water. This increases the moisture content in the film-forming atmosphere, resulting in a higher moisture content than measured when measuring the ultimate vacuum. The median value of the water pressure ratio (water pressure / inert gas partial pressure) is 0.3 x 10-3 More than that is fine.

[0046] 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, more preferably 8 mm or less, and even more preferably 4 mm or less. If it is 10 mm or less, water and organic components are less likely to be released from the film end face when the film roll is placed in a sputtering device, resulting in good film quality of the transparent conductive film. The height difference may be 1 mm or more.

[0047] Before forming the transparent conductive film, it is desirable to subject the film to a bombardment process. The bombardment process involves applying a voltage to generate a discharge and generate plasma while flowing only an inert gas such as argon gas, or a mixture of an inert gas and a reactive gas such as oxygen. Specifically, it is desirable to bombard the film using RF sputtering with a stainless steel target. The bombardment process exposes the film to plasma, which releases water and organic components from the film. This reduces the amount of water and organic components released from the film during the deposition of the transparent conductive film, improving the quality of the transparent conductive film. In addition, the bombardment process activates the layers that the transparent conductive film comes into contact with, improving the adhesion of the transparent conductive film and further improving its pen sliding durability.

[0048] It is desirable to attach a protective film with low water absorption to the surface of the film to be treated 1 opposite the surface on which the transparent conductive film is formed. By attaching the protective film, gases such as water are less likely to be released from the film to be treated 1, improving the quality of the transparent conductive film. Examples of the base material for the protective film include olefins such as polyethylene, polypropylene, and cycloolefin.

[0049] During film formation, the film to be processed 1 is cooled to, for example, 0°C or below, preferably -5°C or below. By cooling the film to be processed 1, it is possible to suppress the release of impurities such as water and organic gases from the film, thereby ensuring appropriate film quality for the transparent conductive film. The film temperature during film formation can be substituted by the set temperature of a temperature controller that adjusts the temperature of the center roll with which the running film comes into contact (if there are multiple set temperatures, the intermediate value between the maximum and minimum values). The film temperature may be -20°C or above.

[0050] The sputtering apparatus is preferably equipped with an exhaust device such as a rotary pump, a turbomolecular pump, a cryopump, etc. The amount of moisture in the film formation atmosphere can be controlled by the exhaust device.

[0051] After forming and laminating a transparent conductive film of indium-tin composite oxide on the film to be treated, it is desirable to perform a heat treatment in an oxygen-containing atmosphere at 80°C or higher and 200°C or lower for 0.1 to 12 hours. By heating at 80°C or higher, the crystallinity of the transparent conductive film can be increased, further improving pen sliding durability. By heating at 200°C or lower, the flatness of the transparent plastic film can be ensured. The temperature is preferably 100°C or higher and 180°C or lower, more preferably 120°C or higher and 170°C or lower. The time is preferably 0.3 to 6 hours, more preferably 0.5 to 2 hours.

[0052] 3.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 stretching it in the longitudinal direction and / or the transverse direction, cooling, and heat-setting it as necessary. Examples of the organic polymer include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate, polyethylene-2,6-naphthalate, polypropylene terephthalate, and polybutylene terephthalate; polyamides such as nylon 6, nylon 4, nylon 66, and 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.

[0053] 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.

[0054] The transparent plastic film substrate may be subjected to 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.

[0055] The thickness of the transparent plastic film substrate is preferably in the range of 100 μm or more and 240 μm or less, and more preferably 120 μm or more and 220 μm or less. The thinner the plastic film, the lower the bending resistance (BR) of the film and the easier it is for the average maximum peak height (AVSp) to satisfy formula (2-1). Furthermore, a plastic film having a thickness of 100 μm or more is preferred because it maintains mechanical strength, resulting in small deformation due to pen input when used in a touch panel and excellent pen sliding durability. On the other hand, a thickness of 240 μm or less is preferred because it maintains light input performance and excellent input stability when used in a touch panel.

[0056] 4.Curing resin layer The curable resin layer is formed, for example, between a transparent plastic film substrate and a transparent conductive film, serving as a base layer for the transparent conductive film. It is also preferable because it can block the deposition of monomers and oligomers generated from the transparent plastic film substrate onto the transparent conductive film, thereby not impairing the comfortable input performance of the touch panel. Furthermore, the adhesive layer or the like strongly adheres the transparent conductive film to the curable resin layer and can distribute the force applied to the transparent conductive film, thereby suppressing cracking, peeling, wear, etc. of the transparent conductive film in a pen sliding durability test.

[0057] The resin of the curable resin layer is not particularly limited as long as it is a resin that can be cured by application of energy such as heating, ultraviolet irradiation, or electron beam irradiation, or by a curing agent, and examples thereof include silicone-based resins, acrylic-based resins, methacrylic-based resins, epoxy-based resins, melamine-based resins, polyester-based resins, and urethane-based resins, which may be used alone or in combination of two or more. From the viewpoint of productivity, it is preferable to use an ultraviolet-curable resin as the main component.

[0058] Examples of 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.

[0059] The curable resin layer preferably contains a curing reaction initiator at least before curing. The curing reaction initiator can be selected depending on the type of curing of the curable resin, and examples include radical polymerization initiators such as thermal polymerization initiators and photopolymerization initiators, and curing agents, with photopolymerization initiators being preferred. The amount of the curing reaction initiator is, for example, 1 part by mass or more and 5 parts by mass or less per 100 parts by mass of the curable resin.

[0060] As the photopolymerization initiator, any known compound that absorbs ultraviolet light and generates radicals can be used without any particular limitation, and examples thereof include various benzoins, phenyl ketones, benzophenones, and the like.

[0061] The curable resin layer preferably contains particles. The particles can form irregularities on the surface of the curable resin layer. Therefore, while the inclusion of particles generally reduces the contact area ratio CA from 100%, it also facilitates control of the average maximum peak height AVSp and the average arithmetic height Sa. Increasing the amount of particles can also reduce the bending resistance BR, making it possible to adjust the bending resistance BR by adjusting the amount of particles. Furthermore, the particles can more effectively exhibit various properties, such as pen sliding durability, anti-Newton ring properties, and film winding properties.

[0062] Examples of the particles include inorganic particles and organic particles. Examples of inorganic particles include silica particles. Examples of organic particles include particles made of polyester resin, polyolefin resin, polystyrene resin, polyamide resin, acrylic resin, etc. The particles may be of one type or two or more types.

[0063] Furthermore, it is preferable to use monodisperse particles as the particles. By using monodisperse particles as particles with a relatively large particle size (e.g., particle A described below), the average maximum peak height AVSp tends to be increased even when the total amount of particles added to the curable resin layer is small, and therefore the average arithmetic height Sa tends to be reduced. Therefore, the use of monodisperse particles as particle A is effective in achieving both input strength characteristics (e.g., prevention of erroneous responses, smooth input performance, etc.) and clarity. Furthermore, the upper and lower displacement ratios of the maximum peak height Sp described below tend to be close to 1.0. Monodisperse particles may also be used as particles with a relatively small particle size (e.g., particle B described below used in combination with particle A).

[0064] The number average particle diameter of particles A, which have a relatively large particle diameter among the particles (even when there is only one type of number average particle diameter, they are referred to as particles A), is, for example, 2 μm to 11 μm, preferably 2 μm to 6 μm, and more preferably 2 μm to 5 μm. The larger the average particle diameter, the larger the average maximum peak height AVSp of the transparent conductive layer, the larger the average arithmetic height Sa, and the smaller the value of the contact area ratio CA tends to be. Even if the number-average particle diameter of particles A is 11 μm or less (for example, about 10 μm), if it is sufficiently large relative to the thickness of the curable resin layer, the average arithmetic height Sa may become too large. In such cases, the average arithmetic height Sa can be reduced by further reducing the number-average particle diameter of particles A or by reducing the amount of particles A added. Even if the number-average particle size of particles A is 2 μm or more (for example, about 3 μm), if the difference between the number-average particle size and the thickness of the curable resin layer is small, the average maximum peak height AVSp may become too small. In such cases, the average maximum peak height AVSp can be increased by increasing the difference between the number-average particle size of particles A and the thickness of the curable resin layer.

[0065] The standard deviation of the particle diameter is, for example, 20% or less of the number average particle diameter, preferably 10% or less of the number average particle diameter, and more preferably 5% or less of the number average particle diameter. The smaller the standard deviation of the particle diameter, the closer both the upper mutation rate and the lower mutation rate of the maximum peak height Sp of the transparent conductive film become to 1.0, which is preferable. Although inorganic particles may be used as the particles A, organic particles are preferred, and acrylic resin particles are more preferred.

[0066] The optimum amount of particles A in the curable resin layer is, for example, 0.1% by mass to 30% by mass, preferably 5% by mass to 25% by mass, relative to 100% by mass of the solid content of the curable resin layer. The greater the amount of particles A, the smaller the value of the contact area ratio CA and the larger the average arithmetic height Sa. Furthermore, the greater the thickness of the curable resin layer, the larger the optimum amount of particles A added. Furthermore, the greater the density of the curable resin layer, the smaller the optimum amount of particles A added.

[0067] In one embodiment, it is preferable to use particles B having a number-average particle diameter of 0.01 μm or more and 1.0 μm or less in combination with the above particles. Two or more types of particles B may be used. If the particle diameter of particles B is 0.01 μm or more, small irregularities can be formed in the transparent conductive layer, which prevents sticking between the fixed electrode and the film electrode in a resistive touch panel when a finger or pen is pressed and slid across the film electrode, thereby preventing a decrease in the accuracy of the touch panel input position. If the particle diameter of particles B is 1.0 μm or less, this tends to increase the contact area ratio CA, which is preferable. When particles B are contained, the amount of particles B in the curable resin layer is, for example, 0.1% by mass to 25% by mass, and preferably 0.5% by mass to 18% by mass, relative to 100% by mass of the solid content of the curable resin layer. When the amount of particles B is large, the value of the contact area ratio CA tends to be small, and the average arithmetic height Sa tends to be large. The standard deviation of the particle size of particles B is, for example, 20% or less of the number average particle size, and preferably 10% or less of the average particle size. Although organic particles may be used as the particles B, inorganic particles are preferred, and silica particles are more preferred.

[0068] It is preferable to use monodisperse particles having a size (number average particle diameter) larger than the thickness of the curable resin layer as particles A and not include particles B, or to use monodisperse particles having a size (number average particle diameter) larger than the thickness of the curable resin layer as particles A and include particles B. This is preferable because it is easy to control the average maximum peak height AVSp depending on the difference between the size (number average particle diameter) of particles A and the thickness of the curable resin layer. However, it is preferable that the size (number average particle diameter) of particles A is 7 times or less the thickness of the curable resin layer. If the size (number average particle diameter) of particles A is 7 times or less the thickness of the curable resin layer, particle detachment tends to be prevented, which is preferable. The ratio of the number average particle diameter of particles A to the thickness of the curable resin layer is preferably 1.1 to 6.0, more preferably 1.2 to 5.0.

[0069] The thickness of the curable resin layer is preferably in the range of 0.1 μm to 10 μm, more preferably in the range of 0.2 μm to 7 μm, and particularly preferably in the range of 0.3 μm to 5 μm. A thickness of 0.1 μm or more is preferable because sufficient protrusions are formed and the added particles are prevented from falling off. Furthermore, a thick curable resin layer tends to increase the bending resistance BR of the transparent conductive film. On the other hand, a thickness of 10 μm or less is preferable because it allows for good productivity and allows the average maximum peak height AVSp to be set to a moderate value.

[0070] By adjusting the particle size and quantity and the thickness of the curable resin layer in this way, the average maximum peak height AVSp of the transparent conductive layer can be made to satisfy formula (2-1) while preventing the contact area ratio CV and the total transmitted image clarity from becoming too small. The film's bending resistance BR and average arithmetic height Sa can also be adjusted. This allows the input start load to be controlled to a low value, shortening the voltage loss time and increasing the total transmitted image clarity, achieving smooth input performance, input stability, and clarity.

[0071] The curable resin layer may contain a resin that is incompatible with the curable resin (hereinafter, sometimes simply referred to as an incompatible resin). By dispersing the incompatible resin in the curable resin layer, unevenness can be formed on the surface of the curable resin layer, thereby improving surface roughness over a wide area. Examples of incompatible resins include polyester resins, polyolefin resins, polystyrene resins, and polyamide resins.

[0072] The curable resin layer is formed by liquefying the curable resin before curing, applying it to the lamination target (e.g., a transparent plastic film substrate, an easy-adhesive layer), and curing it. In addition to the curable resin, the coating may contain a curing reaction initiator (a radical polymerization initiator such as a thermal polymerization initiator or a photopolymerization initiator, a curing agent, etc.; preferably a photopolymerization initiator), particles, a resin incompatible with the curable resin, a solvent, etc. If necessary, other known additives, such as a silicone-based leveling agent, may also be added to the coating liquid. There are no particular limitations on the solvent used; 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.

[0073] The concentration of the curable resin in the coating solution (referred to as solids concentration) can be appropriately selected taking into consideration the viscosity and other factors appropriate for the coating method. The solids concentration is, for example, 35% by mass or more and 58% by mass or less, and preferably 42% by mass or more and 55% by mass or less. A high solids concentration tends to increase the average maximum peak height AVSp, increase the average arithmetic height Sa, and decrease the contact area ratio CA.

[0074] The method for coating the coating liquid onto the lamination target is not particularly limited, and known methods such as bar coating, gravure coating, and reverse coating can be used. The solvent in the coated coating liquid is evaporated and removed in the subsequent drying step. If an incompatible resin (such as a polyester resin) is dissolved in the coating liquid, the incompatible resin will become particles in this drying step and precipitate in the ultraviolet-curable resin. After drying the coating film, a curable resin layer can be formed by performing an appropriate treatment (for example, ultraviolet irradiation) depending on the type of curing.

[0075] The surface to be coated may be subjected to a treatment to improve the adhesion of the curable resin layer, if necessary, before coating the coating liquid. Examples of treatments to improve adhesion include a discharge treatment method using glow or corona discharge to increase the number of carbonyl groups, carboxyl groups, and hydroxyl groups, and a chemical treatment method using an acid or alkali to increase the number of polar groups such as amino groups, hydroxyl groups, and carbonyl groups.

[0076] As described above, various factors must be adjusted to achieve the desired average maximum peak height AVSp, the desired contact area ratio CA, and the desired average arithmetic height Sa. The details are described above. However, to summarize, omitting the details, these can be achieved by utilizing the following relationships. Basically, the larger the particle size, the higher the solids concentration, or the thinner the resin layer, the larger the absolute value of the average maximum peak height AVSp and the larger the average arithmetic height Sa. The average maximum peak height AVSp that satisfies Equation (2-1) varies depending on the bending resistance BP. The smaller the bending resistance BP, the smaller the average maximum peak height AVSp. Furthermore, the larger the average maximum peak height AVSp or the smaller the average arithmetic height Sa, the smaller the contact area ratio CA. However, if two different average particle sizes, large and small, are added to the resin layer, and the large particles are monodispersed and the amount of large particles added is small, the larger the average maximum peak height AVSp, the larger the contact area ratio CV, and the smaller the average arithmetic height Sa. When two types of particles, large and small, are used, the smaller the amount of large particles added, the greater the effect that the average particle size and amount of small particles have on the contact area ratio CA and average arithmetic height Sa.

[0077] 5. Functional Layer The functional layer is preferably basically the same as the curable resin layer except that it is formed on the opposite side of the transparent plastic film substrate. The description of the curable resin layer applies to the functional layer in its entirety (including the type of curable resin layer, the thickness of the curable resin layer, the solids concentration of the curable resin layer, the type of particles, etc.) except for the particle size and amount. Laminating a functional layer on a transparent plastic film substrate can prevent precipitation of monomers and oligomers from the transparent plastic film substrate, thereby suppressing a decrease in the visibility of the transparent conductive film. It also allows the bending resistance BR of the transparent conductive film to be adjusted. Furthermore, having a functional layer on the transparent plastic film substrate is preferable because it makes it less susceptible to scratches caused by writing with a pen or the like.

[0078] To improve clarity, it is preferable that the functional layer does not essentially contain particles. However, particles (particles C) may be added to the functional layer for the purpose of adjusting the bending resistance BR of the transparent conductive film or maintaining the film winding properties. When particles are added, the number-average particle diameter of particles C is, for example, 0.01 μm or more and 1.0 μm or less, preferably 0.01 μm or more and 0.8 μm or less, and more preferably 0.01 μm or more and 0.5 μm or less. The amount of particles C is preferably 0.1 to 50 parts by mass, more preferably 0.3 to 30 parts by mass, and even more preferably 0.5 to 20 parts by mass, per 100 parts by mass of the curable resin in the functional layer. The bending resistance BR of the transparent conductive film can be adjusted by adjusting the amount of particles C. Furthermore, particles C can form surface protrusions on the functional layer, thereby maintaining the film's winding properties. The particles C can be selected from the same types of particles as those of the curable resin layer, and although organic particles are acceptable, inorganic particles are preferred, and silica particles are more preferred.

[0079] In an adhesion test on the surface of the functional layer in accordance with JIS K5600-5-6:1999, the remaining area ratio of the functional layer is preferably 95% or more, more preferably 99% or more, and particularly preferably 99.5% or more. When the remaining area ratio of the functional layer in the adhesion test is within the above range, the transparent conductive film is favorable because the transparent plastic film substrate and the functional layer are in close contact with each other, and appearance defects such as cracking, peeling, and wear of the functional layer are suppressed even when continuous input is made to the touch panel with a pen, and further, cracking, peeling, and the like are suppressed even when a force stronger than expected in normal use is applied to the functional layer.

[0080] When the transparent conductive film has a functional layer and a cured resin layer, it is preferable that the thicknesses of the functional layer and the cured resin layer are the same, and it is preferable that the absolute value of the difference in thickness between the functional layer and the cured resin layer satisfy the following relationship: 0.1 μm≦ |Thickness of cured resin layer - Thickness of functional layer| ≦3 μm By providing a thickness difference between the functional layer and the cured resin layer, the bending resistance BR of the transparent conductive film can be adjusted in some cases. Furthermore, various properties such as pen sliding durability can be more effectively exhibited. Furthermore, input strength characteristics (such as prevention of erroneous responses and light input characteristics) can be further improved. The thickness difference (absolute value) may be 2 μm or less. Furthermore, it is preferable that the particle mass per unit volume of the cured resin layer and the particle mass per unit volume of the functional layer are different.

[0081] 6.Easy adhesive layer The adhesive layer is preferably formed from a composition containing a urethane resin, a crosslinking agent, and a polyester resin. The crosslinking agent is preferably a blocked isocyanate, more preferably a trifunctional or higher functional blocked isocyanate, and particularly preferably a tetrafunctional or higher functional blocked isocyanate. The thickness of the adhesive layer is preferably 0.001 μm or more and 2.00 μm or less.

[0082] This application claims the benefit of priority to Japanese Patent Application No. 2022-021557, filed February 15, 2022. The entire contents of the specification of Japanese Patent Application No. 2022-021557, filed February 15, 2022, are incorporated herein by reference. [Example]

[0083] 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.

[0084] 1. Measurement evaluation (1) Average particle size of silica particles and acrylic particles Three observation sites were randomly selected from the cross section of each of the curable resin layer or functional layer of the transparent conductive film. Particles at each observation site were observed using a scanning electron microscope (Keyence Corporation, VE-8800). Fifty particles were randomly selected from each observation site and their particle diameters were observed. The particle diameters (circle-equivalent diameters) of the 50 observed particles were then divided into 0.020 μm intervals. The total number of particles in each interval was calculated, and a histogram was created with the number of particles on the vertical axis and particle diameters on the horizontal axis in 0.020 μm intervals. For particles with diameters within ±30% of the absolute value of the center of the particle diameter interval where the peak of the normal distribution was observed, the average particle diameter was calculated as the number average of the observed particle diameters. For example, if the histogram has two peaks of the normal distribution, this indicates the addition of two types of particles. The average particle diameters of the two types were calculated using the same method as above. The average particle diameters at three locations in the curable resin layer were further averaged, and the average particle diameter of the curable resin layer and the average particle diameters at three locations in the functional layer were further averaged to obtain the average particle diameter of the functional layer.

[0085] (2) Thickness of the curable resin layer and the functional layer The thickness of the curable resin layer was determined by observing the cross section of the transparent conductive film (Keyence Corporation, VE-8800) at 5000x magnification, randomly selecting five points, and averaging the results to determine the thickness. The same method was used for the thickness of the functional layer.

[0086] (3) Content of tin oxide in the transparent conductive film 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.

[0087] (4) Transparent conductive film thickness Film specimens laminated with a transparent conductive thin film layer were cut into 1 mm x 10 mm pieces and embedded in epoxy resin for electron microscopy. The epoxy resin consisted of the base resin (Epon 812, Nacalai Tesque, Inc.), the curing agent (MNA, Nacalai Tesque, Inc.), and the accelerator (DNP-30, Nacalai Tesque, Inc.) in a volume ratio of 100:89:1.5. The mixture was then cured at 60°C for 12 hours. The epoxy resin-encapsulated specimen was fixed in an ultramicrotome holder, and cross-sectional thin sections parallel to the short edges of the embedded specimen were prepared. Next, a portion of the specimen without significant damage to the thin film was photographed using a transmission electron microscope (JEOL, JEM-2010) at an accelerating voltage of 200 kV and a bright-field magnification of 10,000x. The film thickness was determined from the resulting photographs.

[0088] (5) Crystallinity of transparent conductive film A film sample laminated with a transparent conductive film was cut into 1 mm x 10 mm pieces and attached to the top of a suitable resin block with the conductive film facing outward. The resin block consisted of a base resin (Epon 812, Nacalai Tesque, Inc.), a curing agent (MNA, Nacalai Tesque, Inc.), and an accelerator (DNP-30, Nacalai Tesque, Inc.) mixed in a volume ratio of 100:89:1.5, and cured at 60°C for 12 hours. The sample was trimmed and then cut into ultrathin sections parallel to the film surface using a standard ultramicrotome. The sections were observed under a transmission electron microscope (JEOL, JEM-2010) at an accelerating voltage of 200 kV and a direct magnification of 40,000x. The undamaged conductive thin film surface was selected and photographed. The crystallinity of the transparent conductive film was evaluated by observing the proportion of crystal grains under a transmission electron microscope, that is, the degree of crystallinity.

[0089] (6) Total light transmittance (%) The total light transmittance was measured using NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS-K7361-1:1997.

[0090] (7) 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.

[0091] (8) Adhesion test The test was carried out in accordance with JIS K5600-5-6:1999. The results in the table below show the adhesion as a remaining area rate (%). The maximum remaining area rate is 100%. The closer the remaining area rate in the adhesion test in the table is to 100%, the smaller the peeled area.

[0092] (9) Bending resistance (BR) (Test method 3) A 20mm x 250mm test piece was taken from the transparent conductive film and placed on a smooth horizontal table with the transparent conductive film facing up. Only a 20mm x 20mm section from one end of the test piece was placed on the horizontal table, leaving a 20mm x 230mm section protruding horizontally from the edge of the table. A weight was placed on the 20mm x 20mm section of the test piece, and the weight and size of the weight were selected to prevent any gaps between the test piece and the horizontal table. Next, the difference (δ) between the height of the horizontal table and the height of the tip of the film was read on a scale. The bending resistance was calculated by substituting the values ​​into the following formula. Bending resistance BR (N cm)=g×a×b×L 4 / (8×δ×10 11 ) (where a is 9.81 (gravitational acceleration; m / s 2 ), and b is the specific gravity of the test piece (g / cm 3 ), L is 230 (the length of the long side of the test piece outside the horizontal table; mm), and δ is the difference in height between the tip of the test piece and the height of the table (cm). The specific gravity b was measured by the following method. The transparent conductive film was cut into a 5.0 cm square, and the total thickness was measured at 10 different locations using a micrometer to three significant digits, and the average thickness (t: μm) was calculated. The weight (w: g) of the sample cut into a 5.0 cm square was measured to four significant digits using an automatic top-pan balance, and the specific gravity was calculated using the following formula. The specific gravity was rounded to two significant digits. Specific gravity b(g / cm 3 )=w / (5.0×5.0×t×10 -4 )

[0093] (10) Maximum peak height (Sp), average maximum peak height AVSp (μm) (Test Method 4) The maximum peak height (Sp) (ISO; surface roughness) was measured at five points on the conductive surface of the transparent conductive film, and the arithmetic mean value was defined as the average maximum peak height (AVSp). The five points were selected by first selecting one arbitrary point A. Next, two points were selected, one 1 cm upstream and one 1 cm downstream from A in the longitudinal (MD) direction of the film. Next, two points were selected, one 1 cm to the left and one 1 cm to the right and one 1 cm to the left and right in the transverse (TD) direction of A. The maximum peak height (Sp) (ISO; surface roughness) was determined using a 3D surface profiler, VertScan (R5500H-M100, manufactured by Ryoka Systems Co., Ltd., measurement conditions: wave mode, measurement wavelength: 560 nm, objective lens: 10x). Values ​​less than 1 nm were rounded off.

[0094] (11) Maximum peak height upper displacement ratio (MXSp / AVSp), maximum peak height lower displacement ratio (MNSp / AVSp) The ratio of the maximum value MXSp of the maximum peak height Sp obtained by the above-mentioned Test Method 4 to the average value AVSp was defined as the maximum peak height upward displacement ratio (MXSp / AVSp). The ratio (MNSp / AVSp) of the minimum value MNSp of the maximum peak height Sp obtained by the above-mentioned test method 4 to the average value AVSp was defined as the maximum peak height downward displacement rate.

[0095] (12) Contact area ratio CA (%), average height Rc (μm), maximum peak height Rp (μm), average length Rsm (μm), arithmetic mean height Ra (μm) (Test method 5) The average height Rc (μm), maximum peak height Rp (μm), and average length Rsm (μm) of the conductive surface of the transparent conductive film due to line roughness were measured, and the arithmetic mean height Ra (μm) of the line roughness was measured at locations where at least one of formulas (X1) and (X2) and formula (X3) were satisfied. The average height Rc (μm), maximum peak height Rp (μm), average length Rsm (μm), and arithmetic mean height Ra (μm) were determined using a 3D surface profiler, VertScan (R5500H-M100, manufactured by Ryoka Systems Co., Ltd. (measurement conditions: wave mode, measurement wavelength 560 nm, objective lens 50x). The maximum peak height Rp (μm), average length Rsm (μm), and arithmetic mean height Ra (μm) were determined in accordance with the provisions of JIS B 0601-2001. The measurement length of the arithmetic mean height Ra (μm) was set to 100 μm or more and 200 μm or less. Rp-Rc-Ra≦0.20…Formula (X1) (Rp-Rc) / Ra≦5.0…Formula (X2) Rsm≦30…Formula (X3) The objective lens of the 3D surface shape measuring device, Bart Scan, was changed to 10x, and the particle analysis in the measuring device was used to calculate the "arithmetic mean height Ra (μm) - 15 × 10 -3 The height where "(μm) - average height Rc (μm)" was used as a threshold value, and the sample was sliced ​​in the planar direction to calculate the sum of the cross-sectional areas. The sum of the cross-sectional areas was divided by the area of ​​the measurement field of view, and the result multiplied by 100 was used to calculate the contact area ratio (CA) (%).

[0096] (13) Input start load measurement (Test method 1) After placing the glass substrate (size: 232 mm × 151 mm) in the sputtering device, -4 The chamber was evacuated to a vacuum of 10 mPa. Oxygen was then introduced to 10 mPa, followed by argon, to bring the total pressure to 0.6 Pa. An indium-tin composite oxide sintered target was used, and the pressure was 3 W / cm. 2A 20 nm thick indium-tin composite oxide conductive film (tin oxide content: 10 wt%) was formed on one side of a glass substrate by DC magnetron sputtering using a power density of 1000 W. Next, dot spacers (60 μm length × 60 μm width × 5 μm height) made of UV-curable resin (product name "CR-103C-1" manufactured by Toyobo Co., Ltd.) were formed on the surface of the conductive film at a 4 mm pitch in a square lattice pattern (ITO glass substrate). Double-sided tape (product name "#741" manufactured by Ebisu Chemical Industry Co., Ltd.) cut to a specified size (thickness: 105 μm, width: 6 mm) was attached to the transparent conductive film side so that a 190 mm × 135 mm rectangle was formed starting from one of the four corners of the ITO glass substrate. This double-sided tape formed an adhesive rectangular frame with a thickness of 105 μm and an inner circumference of 190 mm × 135 mm. The transparent conductive film (size: 220 mm × 135 mm) obtained in the Examples or Comparative Examples was attached to a rectangular frame (double-sided tape) attached to an ITO glass substrate without applying tension, and the conductive films were laminated so that the conductive films faced each other. At this time, one short side of the transparent conductive film protruded from the ITO glass substrate (evaluation panel). The ITO glass substrate and transparent conductive film of the obtained evaluation panel were connected with a tester. A load was applied from the transparent conductive film side using a polyacetal pen (trade name "TPS (registered trademark) POM (NC)" manufactured by Toray Plastics Precision Co., Ltd., tip shape: 0.8 mmR). The load value when the resistance value measured by the tester stabilized (i.e., when the resistance value fluctuation was within ±5%) was defined as the input starting load. The position 12 where the load was applied with the pen was the central region of four dot spacers 11 arranged in a grid on the surface of the ITO glass substrate 10, as shown in Figure 7. The input start load was measured at three arbitrary points 50 mm or more away from the double-sided tape and the average value was calculated. The value was rounded to the nearest whole number.

[0097] (14) Voltage loss time measurement (Test method 2) A constant-voltage power supply was connected to the evaluation panel prepared for the input load measurement. A recorder (Keyence GR-7000) capable of measuring the voltage between the ITO glass substrate and the transparent conductive film was then connected. The recorder was used to observe the time course of the voltage. 6 V was then applied to the constant-voltage power supply, and the recorder began measuring the voltage in 0.02-millisecond increments. Next, a 50 g load was applied to the transparent conductive film side five times per second (30 mm strokes) using a polyacetal pen (product name "TPS (registered trademark) POM (NC)" manufactured by Toray Plastics Precision Co., Ltd., tip shape: 0.8 mmR). The pen applied the load at the center of the four dot spacers arranged in a grid pattern. The data on the time course of the voltage as the pen applied the load to the transparent conductive film was retrieved from the recorder. The time from when the pen began to separate from the transparent conductive film and the voltage decreased from 6 V to when the voltage reached 5 V was measured and recorded as the voltage loss time (see Figure 5). The results of three measurements were averaged.

[0098] (15) Input strength test (prevention of false reactions and smooth input) A resistive touch panel was fabricated using the transparent conductive films obtained in the examples and comparative examples. Specifically, a glass substrate (size: 232 mm × 151 mm) was first placed in a sputtering device, and then a 1.5 × 10 -4 The chamber was evacuated to a vacuum of 10 mPa. Oxygen was then introduced to 10 mPa, followed by argon, to bring the total pressure to 0.6 Pa. An indium-tin composite oxide sintered target was used, and the pressure was 3 W / cm. 2A 20 nm thick indium-tin composite oxide conductive film (tin oxide content: 10 wt%) was formed on one side of a glass substrate by DC magnetron sputtering using a power density of 1000 W. Next, dot spacers (circular (30 μm length × 30 μm width) × 4 μm height) made of UV-curable resin (product name "CR-103C-1" manufactured by Toyobo Co., Ltd.) were formed on the surface of the conductive film at a 4 mm pitch in a square lattice pattern (ITO glass substrate). Double-sided tape (product name "#741" manufactured by Ebisu Chemical Industry Co., Ltd.) cut to a specified size (thickness: 105 μm, width: 6 mm) was attached to the transparent conductive film side so that a 190 mm × 135 mm rectangle was formed starting from one of the four corners of the ITO glass substrate. This double-sided tape formed an adhesive rectangular frame with a thickness of 105 μm and an inner circumference of 190 mm × 135 mm. The transparent conductive film (size: 220 mm x 135 mm) obtained in the Example or Comparative Example was attached to a rectangular frame (double-sided tape) attached to an ITO glass substrate without applying tension, and the conductive films were stacked so that they faced each other. At this time, one short side of the transparent conductive film protruded from the ITO glass substrate. Two positioning wires for the X coordinate were attached to the ITO glass substrate, and two positioning wires for the Y coordinate were attached to the transparent conductive film, forming a four-wire analog resistive touch panel. The input strength was examined using a polyacetal pen (trade name "TPS (registered trademark) POM (NC)", manufactured by Toray Plastics Precision Co., Ltd., tip shape: 0.8 mmR). (Prevents false reactions) ○...Even if the pen touches the touch panel lightly (with a load of about 1 to 2 g), no input is made to the touch panel. ×...When the pen touches the touch panel lightly (with a load of about 1 to 2 g), input may be made to the touch panel. (Easy input) ○...You can input with just a light touch (a load of about 3 to 15 g), meaning you don't have to consciously apply strong force. ×...You cannot input data with a light touch (a load of about 3 to 15 g), that is, unless you consciously apply a strong force.

[0099] (16) Input stability (writing stability, shorthand stability) Using the transparent conductive films obtained in the examples and comparative examples, touch panels identical to the 4-wire analog resistive touch panels used in (15) Input Strength Test (Prevention of False Responses and Smooth Input) were produced. Input stability was examined using a polyacetal pen (product name "TPS (registered trademark) POM (NC)", manufactured by Toray Plastics Precision Co., Ltd., tip shape: 0.8 mmR). (Payment stability) ○...When entering characters, the strokes are less likely to be blurred. ×...When entering characters, the strokes tend to be faint. (shorthand) ○: When characters are input continuously, the characters are less likely to be blurred. ×: Characters tend to be blurred when entering characters continuously.

[0100] (17) Pen sliding durability (Test method 6) After placing the glass substrate (size: 60 mm × 50 mm) in the sputtering device, -4 The chamber was evacuated to a vacuum of 10 mPa. Oxygen was then introduced to 10 mPa, followed by argon, to bring the total pressure to 0.6 Pa. An indium-tin composite oxide sintered target was used, and the pressure was 3 W / cm. 2A 20 nm-thick indium-tin composite oxide conductive film (tin oxide content: 10% by mass) was formed on one side of the glass substrate by DC magnetron sputtering. Double-sided tape (product name "No. 500" manufactured by Nitto Denko Corporation) (thickness: 170 μm, width: 5 mm) was attached to the transparent conductive film side so that a 40 mm × 40 mm square was formed starting from one of the four corners of the ITO glass substrate. This attached double-sided tape formed an adhesive rectangular frame with a thickness of 170 μm and an inner circumference of 40 mm × 40 mm. A transparent conductive film (size: 60 mm × 50 mm) obtained in the Examples or Comparative Examples was attached to the rectangular frame (double-sided tape) attached to the ITO glass substrate without applying tension, so that the conductive films faced each other. At this time, the transparent conductive film was allowed to protrude from the ITO glass substrate (evaluation panel). The ITO glass substrate and transparent conductive film of the obtained evaluation panel were connected with a tester. Next, a load of 2.5 N was applied to a polyacetal pen (trade name "TPS (registered trademark) POM (NC)", manufactured by Toray Plastics Precision Co., Ltd., tip shape: 0.8 mmR), and a linear sliding test was performed on the touch panel 50,000 times. The sliding location was near the center of the evaluation panel. 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 fixed electrode come into contact) was measured when the center of the sliding part was pressed with a pen load of 0.8 N. An ON resistance of 10 kΩ or less is more preferable.

[0101] (18) Sum of transmitted image clarity The transparent conductive film was measured in accordance with JIS K7374 using an image clarity measuring instrument (Image Clarity Meter ICM-1T manufactured by Suga Test Instruments Co., Ltd.) with optical combs of 0.125 mm width, 0.25 mm width, 0.5 mm width, 1 mm width, or 2 mm width. The sum of the transmitted image clarity for each optical comb was calculated.

[0102] (19) Mean arithmetic height Sa The average arithmetic height Sa of the transparent conductive layer side of the transparent conductive film was determined in accordance with ISO 25178 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 value was rounded to the nearest tenth in nm.

[0103] 2.Laminated film In the examples, the following laminated films were used, each comprising a transparent plastic film substrate, a curable resin layer, and a functional layer. (1) Base material Substrate 1 (transparent plastic film substrate): biaxially oriented transparent PET film (A4380, manufactured by Toyobo Co., Ltd., thickness shown in Table 1) having easy-adhesion layers on both sides (applies to Examples 1 to 8 and Comparative Examples 1, 2, 3, 6, and 7). Substrate 2 (transparent plastic film substrate): A biaxially oriented transparent PET film (manufactured by Toyobo Co., Ltd., A4180, thickness shown in Table 1) having an easy-adhesion layer on one side and no easy-adhesion layer on the other side (applies to Comparative Examples 4 and 5). Substrate 3 (transparent plastic film substrate): The adhesive surface of a biaxially oriented transparent PET film (manufactured by Toyobo Co., Ltd., A4180, thickness shown in Table 1) without an adhesive layer on one side was wiped with a Bemcot (manufactured by Asahi Kasei Corporation) soaked in methyl ethyl ketone to remove the adhesive layer (corresponding to Comparative Example 8).

[0104] (2) Curing resin layer Particles (particles A, particle B) with the number-average particle size shown in Table 1 were blended in the amounts shown in Table 1 with 100 parts by mass of a photopolymerization initiator-containing acrylic resin (Seikabeam (registered trademark) EXF-01J, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.). Particles A were monodispersed acrylic particles or polydispersed acrylic particles. Particles B were monodispersed silica particles. A mixed solvent of toluene / methyl ethyl ketone (MEK) (8 / 2: mass ratio) was added so that the solid content concentration was the value shown in Table 1, and the mixture was stirred to dissolve uniformly, preparing a coating solution (coating solution A). Coating solution A, prepared so that the coating thickness was the value shown in Table 1, was applied to one side of a transparent plastic film substrate using a Meyer bar. 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 ) and the coating was cured.

[0105] (3) Functional layer Silica particles (particles C) having the number-average particle size shown in Table 2 were blended in the amount shown in Table 2 with 100 parts by mass of a photopolymerization initiator-containing acrylic resin (Seikabeam (registered trademark) EXF-01J, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.). A mixed solvent of toluene / MEK (8 / 2: mass ratio) was added as the solvent so that the solid content concentration was the value shown in Table 2, and the mixture was stirred to dissolve uniformly, thereby preparing a coating solution (coating solution C). Coating solution C, which had been prepared so that the coating film thickness was the value shown in Table 2, was applied to the surface of a transparent plastic film substrate opposite the curable resin layer using a Meyer bar. 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 ) and the coating was cured.

[0106] Examples 1 to 8 The laminated film was placed in the vacuum chamber and 1.5 x 10 -4 The chamber was evacuated to a vacuum of 0.6 Pa. Next, oxygen was introduced, followed by argon, to bring the total pressure to 0.6 Pa. The flow rate ratio of oxygen to argon is shown in Table 3. As shown in Figure 6, a transparent conductive film was formed by sputtering from a target 4 in a chimney 3 onto a curable resin layer of a laminated film (film to be treated) 1 on a center roll 2. A sintered target of indium-tin composite oxide (the tin oxide concentration is shown in Table 3, the remainder is indium oxide) was used as the target 4, and the sputtering power was 3 W / cm. 2 A transparent conductive film was deposited by DC magnetron sputtering at a power density of 1000 . The film thickness was controlled by changing the speed at which the film passed over the target. The ratio of water pressure to argon in the film formation atmosphere during sputtering was measured using a gas analyzer (Transpector XPR3, manufactured by Inficon), and is shown in Table 3. As shown in Table 3, the water pressure ratio was adjusted by the presence or absence of a bombardment process, the presence or absence of a protective film, the unevenness of the film roll end surface, and adjusting the temperature of the heating medium in the temperature regulator that controls the temperature of the center roll with which the film runs in contact. In the bombardment process, SUS (stainless steel) was used as the target, and the temperature was 0.5 W / cm 2 RF sputtering was performed at 1000 K. The amount of gas introduced for RF sputtering was the same as the amount of gas introduced into the vacuum device described in the Examples. When a protective film was used, a polyethylene film with a thickness of 65 μm was used. An acrylic adhesive was applied to one side of the protective film. A protective film was attached to the side of the laminated film opposite the side on which the transparent conductive film was formed. The temperature of the heating medium was taken as the value listed in Table 3, which was the temperature exactly halfway between the maximum and minimum temperatures from the start to the end of film formation on the film roll. The film on which the transparent conductive film was laminated was subjected to a heat treatment shown in Table 3 to obtain a transparent conductive film. The obtained transparent conductive films were evaluated for the film thickness, crystallinity, total light transmittance (%), surface resistance (Ω / □), adhesion to the transparent conductive film, and adhesion to the functional layer. The results are shown in Table 4.

[0107] The bending resistance (BR), average maximum peak height (AVSp), contact area ratio (CA), maximum peak height upward displacement ratio (MXSp / AVSp), and maximum peak height downward displacement ratio (MNSp / AVSp) were measured for the obtained transparent conductive film. The results are shown in Table 5.

[0108] The obtained transparent conductive film was examined for input start load, voltage loss time, input strength test (false response prevention, light input), input stability (wiping stability, shorthand stability), total transmitted image clarity, and pen sliding durability. The results are shown in Table 6.

[0109] Comparative Examples 1 to 8 Transparent conductive films were produced in the same manner as in Examples 1 to 8, except that laminate films produced under the conditions shown in Tables 1 and 2 were used and transparent conductive films were formed under the conditions shown in Table 3. In Comparative Example 6, an indium oxide sintered target not containing tin oxide was used as target 4 instead of the indium-tin composite oxide sintered target. The properties of the obtained films are shown in Tables 4 to 6. [Table 1] [Table 2] [Table 3] [Table 4] [Table 5] [Table 6] [Industrial Applicability]

[0110] Transparent conductive films can be widely used in electrical and electronic applications, such as flat panel displays such as liquid crystal displays and electroluminescence (EL) displays, and transparent electrodes for touch panels. [Explanation of symbols]

[0111] 1. Film to be processed 2 Center Roll 3 Chimney 4. Target 5. Transparent conductive film 6 Curing resin layer 7. Transparent plastic film substrate 8 Functional Layer 9 Easy adhesive layer 10 ITO glass substrate 11 Dot Spacer 12 Position to apply load with pen 13 hours 14 Voltage 15 Voltage loss time

Claims

1. A transparent conductive film having a transparent conductive film of indium-tin composite oxide laminated on at least one surface of a transparent plastic film substrate, The input start load determined by test method 1 is 3 g or more and 15 g or less, The voltage loss time determined by Test Method 2 is 0.00 milliseconds or more and 0.40 milliseconds or less, A transparent conductive film in which the sum of five types of transmitted image clarity measured in accordance with JIS K7374 using an image clarity measuring device using five types of optical combs each having a width of 0.125 mm, 0.25 mm, 0.5 mm, 1 mm, or 2 mm is 400 to 500%. [Test Method 1] A 20 nm thick indium-tin composite oxide conductive film (tin oxide content: 10% by mass) was formed on one side of a glass substrate, and dot spacers (60 μm long x 60 μm wide x 5 μm high) were formed on the surface of the thin film in a square lattice pattern with a 4 mm pitch to form a panel plate. An adhesive rectangular frame with a thickness of 105 μm and an inner circumference of 190 mm x 135 mm was sandwiched between the conductive film side of this panel plate, and a transparent conductive film was layered on top of it so that the conductive films faced each other to produce an evaluation panel. From the transparent conductive film side of this evaluation panel, the center of the four-point grid of dot spacers was pressed with a hemispherical polyacetal pen with a radius of 0.8 mm. The pressure when the resistance value began to stabilize was defined as the input starting load. [Test Method 2] The evaluation panel was connected to a 6 V constant voltage power supply, and a pen with a hemispherical tip having a radius of 0.8 mm was used to press the center of the four-point lattice of the dot spacer from the transparent conductive film side with a load of 50 gf at intervals of 5 times per second. The time when the pen began to separate from the transparent conductive film and the voltage decreased from 6 V was taken as the starting point, and the time until the voltage reached 5 V was measured and recorded as the voltage loss time.

2. The film bending resistance (BR) determined by Test Method 3 is 0.23 N cm or more and 0.90 N cm or less, The average (AVSp) of the maximum peak heights Sp of the conductive surface obtained by Test Method 4 satisfies the following formulas (2-1) and (2-2): The contact area ratio (CA) calculated by Test Method 5 satisfies the following formula (2-3): The transparent conductive film according to claim 1, wherein the arithmetic mean height Sa (based on ISO 25178) is 1 to 55 nm. AVSp≧4.7×BR-1.8...Formula (2-1) 0.005≦AVSp≦12.000...Formula (2-2) CA≧32.6×BR+17.2…Formula (2-3) (wherein BR is the film bending resistance (N cm), AVSp is the average maximum peak height (μm), and CA is the contact area ratio (%).) [Test Method 3] A 20 mm x 250 mm transparent conductive film test piece is placed on a horizontal table with the transparent conductive film facing up, and the test piece is allowed to protrude from the edge of the table by a length of 230 mm, and the bending resistance (BR) is determined based on the following formula. Stiffness / softness (BR (N·cm)) = g × a × b × L ４ / (8×δ×10 １１ ) (where a is 9.81 (gravitational acceleration; m / s ２ ), and b is the specific gravity of the test piece (g / cm ３ ), L is 230 (the length of the long side of the test piece that extends outside the horizontal table; mm), and δ is the difference in height between the tip of the test piece and the height of the table (cm). [Test Method 4] A total of five measurement points are determined on the conductive surface of the transparent conductive film: three points at 1 cm intervals in the MD direction and two points symmetrically from the center in the TD direction. The maximum peak height Sp (in accordance with ISO 25178) due to surface roughness is measured at each point, and the average value is taken as the average maximum peak height (AVSp) (μm). [Test Method 5] The average height Rc (μm), maximum peak height Rp (μm), and average length Rsm (μm) due to line roughness are measured for the conductive surface of the transparent conductive film, and the arithmetic mean height Ra (μm) due to line roughness is measured at locations that satisfy at least one of formulas (X1) and (X2) and formula (X3). The average height Rc (μm), maximum peak height Rp (μm), average length Rsm (μm), and arithmetic mean height Ra (μm) are determined using a three-dimensional surface profiler, Bertscan (Rhioka Systems Co., Ltd., R5500H-M100 (measurement conditions: wave mode, measurement wavelength 560 nm, objective lens 50x)). The determination of the maximum peak height Rp (μm), average length Rsm (μm), and arithmetic mean height Ra (μm) is in accordance with the provisions of JIS B 0601-2001. The measurement length of the arithmetic mean height Ra (μm) is set to 100 μm or more and 200 μm or less. Rp-Rc-Ra≦0.20...Formula (X1) (Rp-Rc) / Ra≦5.0...Formula (X2) Rsm≦30...Formula (X3) The objective lens of the three-dimensional surface shape measuring device, Vert Scan, was changed to 10 times, and the particle analysis in the measuring device was used to calculate the "arithmetic mean height Ra (μm) - 15 × 10" from the average surface. －３ The height "(μm) - average height Rc (μm)" is used as a threshold value, and the sample is sliced ​​in the planar direction to determine the sum of the cross-sectional areas. The sum of the cross-sectional areas is divided by the area of ​​the measurement field of view, and the result multiplied by 100 is the contact area ratio (CA) (%).

3. The maximum value MXSp of the maximum peak heights Sp obtained by the test method 4 is more than 1.0 times and not more than 1.4 times the average maximum peak height AVSp, and 3. The transparent conductive film according to claim 2, wherein the minimum value MNSp of the maximum peak heights Sp determined by Test Method 4 is 0.6 to 1.0 times the average maximum peak height AVSp.

4. 3. The transparent conductive film according to claim 1, wherein the transparent conductive film has a thickness of 10 nm or more and 100 nm or less.

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

6. A curable resin layer is provided between the transparent conductive film and the transparent plastic film substrate, The transparent conductive film according to claim 1 or 2, further comprising a functional layer on the opposite side of the transparent plastic substrate from the transparent conductive film.

7. 3. The transparent conductive film according to claim 1, further comprising an easy-adhesion layer on at least one side of the transparent plastic film substrate.

8. The transparent conductive film according to claim 7 , wherein the easy-adhesion layer is disposed at least one of between the transparent plastic film substrate and the curable resin layer and between the transparent plastic substrate and the functional layer.

9. 3. The transparent conductive film according to claim 1, wherein the ON resistance determined by Test Method 6 is 10 kΩ or less. [Test Method 6] An evaluation panel was prepared by stacking a panel plate with a 20 nm thick indium-tin composite oxide conductive film (tin oxide content: 10% by mass) formed on one side of a glass substrate and a transparent conductive film, with the conductive films facing each other. The transparent conductive film side of this evaluation panel was slid with a hemispherical polyacetal pen with a 0.8 mm radius tip while applying a load of 2.5 N (50,000 reciprocating strokes, sliding distance: 30 mm, sliding speed: 180 mm / sec). After sliding, the center of the sliding section was pressed with a pen load of 0.8 N to establish an electrical connection, and the resistance (ON resistance) was measured.

10. 3. The transparent conductive film according to claim 1, wherein the remaining area ratio of the transparent conductive film on the surface of the transparent conductive film is 95% or more in an adhesion test in accordance with JIS K5600-5-6:1999.

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