WO2022070609A1

WO2022070609A1 - Transparent conductive film

Info

Publication number: WO2022070609A1
Application number: PCT/JP2021/029153
Authority: WO
Inventors: 央多々見
Original assignee: 東洋紡株式会社
Priority date: 2020-09-29
Filing date: 2021-08-05
Publication date: 2022-04-07
Also published as: JPWO2022070609A1; CN115769315A; TW202219989A

Abstract

[Problem] The present invention provides a transparent conductive film which is excellent in terms of pen sliding durability, pen weight pressure durability and high definition when used in a touch panel. [Solution] A transparent conductive film which is obtained by superposing a transparent conductive membrane of an indium-tin composite oxide on at least one surface of a transparent plastic film base material, wherein: the ON resistance of the transparent conductive membrane of the transparent conductive film as determined by a pen sliding durability test is 10kΩ or less; the rate of increase of the surface resistance value of the transparent conductive membrane of the transparent conductive film as determined by a pen weight pressure test is 1.5 or less; and the total sharpness of transmitted images of the transparent conductive film at the comb widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm is not less than 250% but less than 500%.

Description

Transparent conductive film

The present invention relates to a transparent conductive film in which a transparent conductive film of a crystalline indium-tin composite oxide is laminated on a transparent plastic film base material, particularly a pen sliding durability when used for a resistance film type touch panel. It relates to a transparent conductive film having excellent heavy pressure durability and high definition.

A transparent conductive film in which a transparent and low-resistance thin film is laminated on a transparent plastic base material is used for applications that utilize the conductivity, for example, flat panel displays such as liquid crystal displays and electroluminescence (EL) displays. , As a transparent electrode for touch panels, etc., is widely used in applications in the electrical and electronic fields.

The resistance film type touch panel is a combination of a fixed electrode coated with a transparent conductive thin film on a glass or plastic substrate and a movable electrode (= film electrode) coated with a transparent conductive thin film on a plastic film. It is used by stacking it on the upper side. Pressing the film electrode with a finger or a pen to bring the fixed electrode and the transparent conductive thin film of the film electrode into contact with each other is an input for position recognition of the touch panel. Compared to fingers, pens often exert more force on the touch panel. If the touch panel is continuously input with a pen, the transparent conductive thin film on the film electrode side may be broken such as cracks, peeling, and wear. In addition, if a stronger force than expected for normal use, such as hitting the touch panel violently with a pen or inputting with a pen with a very strong force, is applied to the touch panel, the transparent conductive thin film may be cracked or peeled off. In order to solve these problems, there is a demand for a transparent conductive film having both excellent pen sliding durability and excellent pen heavy pressure durability. Further, it is required that the image on the touch panel has high definition.

As a means for improving the pen sliding durability, there is a method of making the transparent conductive thin film on the film electrode side crystalline (see, for example, Patent Document 1). However, the conventional transparent conductive film realizes a transparent conductive film having excellent pen sliding durability by controlling the crystallinity of the indium-tin composite oxide. However, the conventional transparent conductive film was insufficient when the pen heavy pressure durability test described later was carried out.

Japanese Unexamined Patent Publication No. 2004-071171

In view of the above-mentioned conventional problems, an object of the present invention is transparency that is excellent in pen sliding durability when used for a touch panel, is also excellent in pen heavy pressure durability, and can provide a high-definition image. The purpose is to provide a conductive film.

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. 1. A transparent conductive film in which a transparent conductive film of an indium-tin composite oxide is laminated on one surface of a transparent plastic film substrate, and is a transparent conductive film of the transparent conductive film according to the following pen sliding durability test. The ON resistance is 10 kΩ or less, the increase rate of the surface resistance value of the transparent conductive film of the transparent conductive film by the following pen heavy pressure test is 1.5 or less, and the comb widths are 0.125 mm and 0.25 mm. A transparent conductive film having a total transmission image sharpness of 250% or more and less than 500% at 0.5 mm, 1.0 mm, and 2.0 mm.
(Pen sliding durability test method)
The transparent conductive film according to the present invention is used as one panel plate, and the other panel plate is an indium-tin composite oxide thin film having a thickness of 20 nm by a sputtering method on a glass substrate (tin oxide content: 10% by mass). A transparent conductive thin film made of is used. The two panel plates are arranged via epoxy beads having a diameter of 30 μm so that the transparent conductive thin films face each other, and the film side panel plate and the glass side panel plate are attached with double-sided tape having a thickness of 170 μm. , Make a touch panel. Next, a load of 2.5 N is applied to a polyacetal pen (tip shape: 0.8 mmR), and a linear sliding test of 180,000 reciprocations is performed on the touch panel. In this test, a pen load is applied to the transparent conductive film surface according to the present invention.
At this time, the sliding distance is 30 mm and the sliding speed is 180 mm / sec. After this sliding durability test, the ON resistance (resistance value when the movable electrode (film electrode) and the fixed electrode come into contact with each other) when the sliding portion is pressed with a pen load of 0.8 N is measured.
(Pen heavy pressure test method)
The transparent conductive film according to the present invention cut to 50 mm × 50 mm is used as one panel plate, and the other panel plate is an indium-tin oxide composite oxide thin film (tin oxide) having a thickness of 20 nm on a glass substrate by a sputtering method. A transparent conductive thin film having a content of 10% by mass) is used. The two panel plates are arranged via epoxy beads having a diameter of 30 μm so that the transparent conductive thin films face each other, and the thickness is adjusted to 120 μm with double-sided tape. The panel plate on the film side and the panel on the glass side. A touch panel was made by pasting a board. A load of 35 N is applied to a position 2.0 mm from the end of the double-sided tape with a pen made of polyacetal (tip shape 0.8 mmR), and linear sliding is performed 10 times (5 reciprocations) in parallel with the double-sided tape. In this test, a pen load is applied to the transparent conductive film surface according to the present invention. At this time, the sliding distance is 30 mm and the sliding speed is 20 mm / sec. Slide in a position where there are no epoxy beads. After sliding, the transparent conductive film is removed, the surface resistance (4 terminal method) at any 5 points of the sliding part is measured, and the average value is calculated. When measuring the surface resistance, arrange the four terminals in a direction perpendicular to the sliding portion so that the sliding portion comes between the second terminal and the third terminal. The rate of increase in the surface resistance value is calculated by dividing the average value of the surface resistance values of the sliding portion by the surface resistance value of the non-sliding portion (measured by the 4-terminal method).
2. 2. The crystal grain size of the transparent conductive film of the indium-tin composite oxide is 10 to 100 nm, the crystallinity of the transparent conductive film of the indium-tin composite oxide is 20 to 80%, and the crystal size of the transparent conductive film of the indium-tin oxide is 20 to 80%. The transparent conductive film contains 0.5 to 10% by mass of tin oxide, the thickness of the transparent conductive film of the indium-tin composite oxide is 10 to 30 nm, and the thickness of the transparent conductive film of the indium-tin composite oxide is three-dimensional. When the surface roughness SRa is X, X is 1 to 100 nm, and when the three-dimensional surface roughness SRa on the transparent conductive film substrate opposite to the transparent conductive film side is Y, (X ³ ). + Y ³ ) The transparent conductive film according to the first item above, wherein ^1/3 is 140 nm or less.
3. 3. Even if the adhesion test (JIS K5600-5-6: 1999) was performed on the surface of the transparent conductive film, the transparent conductive film did not peel off, and the transparent conductive film was resistant to the transparent conductive film side of the indium-tin composite oxide. The transparent conductivity according to the first or second above, wherein the mandrel diameter is smaller than 20 mm, in which cracking or peeling occurs when a bending part is observed by a bending test (JIS K5600-5: 1: 1999) with a 10-fold loupe. Sex film.
4. The transparent conductive film according to any one of the above 1st to 3rd, wherein the transparent conductive film has a thickness of 100 to 250 μm.
5. The transparent conductive film according to any one of the above 1 to 4, which has a curable resin layer between a transparent conductive film of an indium-tin composite oxide and a transparent plastic film substrate.

According to the present invention, it is possible to provide a transparent conductive film having both excellent pen sliding durability and excellent pen heavy pressure durability, and capable of providing a high-definition image. The obtained transparent conductive film is extremely useful for applications such as a resistance film type touch panel.

It is a schematic diagram which shows an example (the 1) of the longest part of the crystal grain in this invention. It is a schematic diagram which shows another example (the 2) of the longest part of the crystal grain in this invention. It is a schematic diagram which shows another example (the 3) of the longest part of the crystal grain in this invention. It is a schematic diagram which shows another example (the 4) of the longest part of the crystal grain in this invention. It is a schematic diagram for demonstrating the position of the center roll of an example of a sputtering apparatus preferably used in this invention.

The transparent conductive film of the present invention is a transparent conductive film in which a transparent conductive film of an indium-tin composite oxide is laminated on one surface of a transparent plastic film base material, and the following pen sliding durability test is performed. The ON resistance of the transparent conductive film of the transparent conductive film is 10 kΩ or less, and the increase rate of the surface resistance value of the transparent conductive film of the transparent conductive film by the following pen heavy pressure test is 1.5 or less. It is preferable that the total transmission image sharpness of the transparent conductive film at widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm is 250% or more and less than 500%.
(Pen sliding durability test)
The transparent conductive film according to the present invention is used as one panel plate, and the other panel plate is an indium-tin composite oxide thin film having a thickness of 20 nm by a sputtering method on a glass substrate (tin oxide content: 10% by mass). A transparent conductive thin film made of is used. The two panel plates are arranged via epoxy beads having a diameter of 30 μm so that the transparent conductive thin films face each other, and the film side panel plate and the glass side panel plate are attached with double-sided tape having a thickness of 170 μm. , Made a touch panel. Next, a load of 2.5 N was applied to a polyacetal pen (tip shape: 0.8 mmR), and a linear sliding test of 180,000 reciprocations was performed on the touch panel. In this test, a pen load is applied to the transparent conductive film surface according to the present invention. At this time, the sliding distance was 30 mm and the sliding speed was 180 mm / sec. After this sliding durability test, the ON resistance (resistance value when the movable electrode (film electrode) and the fixed electrode came into contact with each other) when the sliding portion was pressed with a pen load of 0.8 N was measured.
(Pen heavy pressure test)
A transparent conductive film obtained by cutting the transparent conductive film according to the present invention into 50 mm × 50 mm is used as one panel plate, and the other panel plate is an indium-tin composite oxide having a thickness of 20 nm by a sputtering method on a glass substrate. A transparent conductive thin film composed of a thin film (tin oxide content: 10% by mass) was used. The two panel plates are arranged via epoxy beads having a diameter of 30 μm so that the transparent conductive thin films face each other, and the thickness is adjusted to 120 μm with double-sided tape. The panel plate on the film side and the panel on the glass side. A touch panel was made by pasting a board. A load of 35 N is applied to a position 2.0 mm from the end of the double-sided tape with a pen made of polyacetal (tip shape 0.8 mmR), and linear sliding is performed 10 times (5 reciprocations) in parallel with the double-sided tape. In this test, a pen load is applied to the transparent conductive film surface according to the present invention. At this time, the sliding distance is 30 mm and the sliding speed is 20 mm / sec. However, sliding is performed at a position where there are no epoxy beads. After sliding, the transparent conductive film is removed, the surface resistance (4 terminal method) at any 5 points of the sliding part is measured, and the average value is calculated. When measuring the surface resistance, arrange the four terminals in a direction perpendicular to the sliding portion so that the sliding portion comes between the second terminal and the third terminal. The rate of increase in the surface resistance value is calculated by dividing the average value of the surface resistance values of the sliding portion by the surface resistance value of the non-sliding portion (measured by the 4-terminal method).

The transparent conductive film of the present invention is excellent in pen sliding durability and pen heavy pressure durability. Pen sliding durability and pen heavy pressure durability are contradictory properties. First, the pen sliding durability will be described. The transparent conductive film of indium-tin composite oxide having excellent pen sliding durability has a high crystallinity of the transparent conductive film and a large crystal grain size. The degree of crystallinity and the crystal grain size will be described. The portion having a circular or polygonal region observed under a transmission electron microscope is defined as a crystal (= crystal grain) of a transparent conductive film, and the other portion is defined as an amorphous. A high degree of crystallinity means a high proportion of crystals. A large crystal grain size means a large circular or polygonal region observed under a transmission electron microscope. A transparent conductive film with a high degree of crystallinity has a high proportion of hard crystals, and a transparent conductive film having a large crystal grain size has a large strain around the crystal grains. Excellent for. Next, the pen heavy pressure durability will be described. A transparent conductive film of an indium-tin composite oxide having excellent pen heavy pressure durability needs to have a low crystallinity of the transparent conductive film, a small crystal grain size, and a small three-dimensional surface roughness of the transparent conductive film. be. The three-dimensional surface roughness will be described later. First, a transparent conductive film having a low crystallinity has a high proportion of soft amorphous, and a transparent conductive film having a small crystal grain size has a small strain around the crystal grains. Therefore, even if a load is applied to the transparent conductive film, cracks are less likely to occur, and the pen heavy pressure durability is excellent. As described above, it can be seen that the pen sliding durability and the pen heavy pressure durability are contradictory properties. As a result of the study, it was invented that the pen sliding durability and the pen heavy pressure durability can be achieved at the same time by controlling the crystallinity and the crystal grain size of the transparent conductive film. A transparent conductive film having a transparent conductive film that achieves both pen sliding durability and pen heavy pressure durability will be described.

In the present invention, if the ON resistance of the transparent conductive film of the transparent conductive film according to the pen sliding durability test is 10 kΩ or less, cracks, peeling, wear, etc. are suppressed with respect to the transparent conductive film even if continuous input is made to the touch panel with a pen. It is preferable because it is used. In one embodiment, the ON resistance may be 9.5 kΩ or less, more preferably 5 kΩ or less. For example, the ON resistance is 3 kΩ or less, may be 1.5 kΩ or less, and is preferably 1 kΩ or less. If the ON resistance is 0 kΩ, the pen sliding durability is very excellent, and in the present invention, the ON resistance can be 0 kΩ. The ON resistance may be, for example, 3 kΩ or more, or 5 kΩ or more.
When the ON resistance is within such a range, cracks, peeling, wear, and the like can be suppressed with respect to the transparent conductive film even if the touch panel is continuously input with a pen.
In one embodiment, these upper and lower limits may be combined as appropriate.

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

In one embodiment, the ON resistance of the transparent conductive film of the transparent conductive film by the pen sliding durability test is 0.05 kΩ or more and 9.5 kΩ or less, and the transparent conductive film by the pen heavy pressure (durability) test. The rate of increase in the surface resistance value of the transparent conductive film is 1.0 or more and 1.5 or less.
As described above, pen sliding durability and pen heavy pressure durability are usually contradictory properties. In the present invention, these two durability can be well-balanced within such a range. In addition, even if continuous input is made to the touch panel with a pen, cracks, peeling, wear, etc. can be suppressed against the transparent conductive film, and in addition, excellent durability is achieved against loads caused by pen sliding and pen heavy pressure. Can be shown. As the numerical range, the range and the value described in the present specification can be selected.

In the present invention, if the total transmission image sharpness of the transparent conductive film at comb widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm is 250% or more and less than 500%, the definition is high. It is desirable because it is possible to provide various images. The larger the total sharpness of the transmitted image, the higher the sharpness of the elephant, that is, the better the high definition. More preferably, the total transmission image sharpness of the transparent conductive film is 300% or more. More preferably, the total transmission image sharpness of the transparent conductive film is 400% or more.
In addition, in this specification, "comb width" means an optical comb width which conforms to JIS-K7105.

In the transparent conductive film of the present invention, the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 10 to 100 nm, and the crystallinity of the transparent conductive film of the indium-tin composite oxide is 20 to 80%. It is preferable to have. When the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 10 nm or more, the transparent conductive film becomes moderately hard due to the strain around the crystal grains of the transparent conductive film, so that the pen sliding durability is excellent. preferable. More preferably, the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 30 nm or more.
On the other hand, when the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 100 nm or less, the transparent conductive film is not too hard due to the strain around the crystal grains of the transparent conductive film, so that the pen heavy pressure durability is improved. It is preferable because it is excellent. More preferably, the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 90 nm or less.
In one embodiment, the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 30 nm or more and 95 nm or less, for example, 40 nm or more and 90 nm or less.
When the crystallinity of the transparent conductive film of the indium-tin composite oxide is 20% or more, it becomes moderately hard due to the hard crystals occupying the transparent conductive film, and the pen sliding durability is excellent, which is preferable. More preferably, the crystallinity of the transparent conductive film of the indium-tin composite oxide is 25% or more. On the other hand, when the crystallinity of the transparent conductive film of the indium-tin composite oxide is 80% or less, the amount of hard crystals contained is large, but the transparent conductive film is not too hard, so that the pen heavy pressure durability is excellent. Therefore, it is preferable.
In one embodiment, the crystallinity of the transparent conductive film of the indium-tin composite oxide is 25% or more and 78% or less, for example, 25% or more and 76% or less.

The transparent conductive film in the present invention preferably has an X of 1 to 100 nm, where X is the three-dimensional surface roughness SRa of the transparent conductive film. When X is 1 to 100 nm, the surface protrusions of the transparent conductive film are small, so that the amount of deformation of the surface protrusions is small when the pen heavy pressure test is performed, crack generation of the transparent conductive film is suppressed, and the transparent conductivity is further suppressed. Since the film has some surface protrusions, it is preferable because the film winding property can be maintained. More preferably, X is 1 to 80 nm. More preferably, X is 1 to 65 nm.

The transparent conductive film in the present invention is made of an indium-tin composite oxide, and preferably contains 0.5% by mass or more and 10% by mass or less of tin oxide. Tin oxide in the indium-tin composite oxide corresponds to an impurity for indium oxide. The inclusion of tin oxide impurities increases the melting point of the indium-tin composite oxide. That is, since the impurity content of tin oxide acts in the direction of inhibiting crystallization, it is an important factor having a strong correlation with crystallinity such as crystal grain size and crystallinity. When tin oxide is contained in an amount of 0.5% by mass or more, the surface resistance of the transparent conductive film becomes a practical level, which is preferable. More preferably, the tin oxide content is 1% by mass or more, and particularly preferably 2% by mass or more. When the tin oxide content is 10% by mass or less, crystallization is likely to occur in adjusting to the semi-crystalline state described later, and the pen sliding durability is good, which is preferable. The tin oxide content is more preferably 8% by mass or less, further preferably 6% by mass or less, and particularly preferably 4% by mass or less. The surface resistance of the transparent conductive film of the present invention is preferably 50 to 900 Ω / □, more preferably 50 to 600 Ω / □.

In the present invention, the thickness of the transparent conductive film is preferably 10 nm or more and 30 nm or less. The thickness of the transparent conductive film is an important factor having a strong correlation with crystallinity such as crystal grain size and crystallinity. When the thickness of the transparent conductive film is 10 nm or more, the transparent conductive film does not have too many amorphous substances, and it is easy to give an appropriate crystal grain size and crystallinity to make a semi-crystalline state, which will be described later, and as a result, the pen slides. Durability is maintained and is preferable. The thickness of the transparent conductive film is more preferably 13 nm or more, more preferably 16 nm or more. Further, when the thickness of the transparent conductive film is 30 nm or less, the crystal grain size of the transparent conductive film is not too large, the crystallinity is not too high, the semi-crystalline state is easily maintained, and the pen heavy pressure durability is maintained. It is preferable that the sex is maintained. It is more preferably 28 nm or less, still more preferably 25 nm or less.

The transparent conductive film in the present invention has (X ³ + Y ³ ) ^1/3 of 140 nm or less, where Y is the three-dimensional surface roughness SRa of the surface of the transparent plastic film substrate opposite to the transparent conductive film side. If this is the case, the total transmission image sharpness of the transparent conductive film at the comb widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm is 250% or more and less than 500%, which is high. This is desirable because it enables the provision of fine images. ((X ³ + Y ³ ) The smaller the value of ^1/3 , the smaller the unevenness on both sides of the transparent conductive film, so that the transmitted image sharpness for improving the straightness of the incident light on the transparent conductive film is improved. It was confirmed that it tended to be higher and used. More preferably (X ³ + Y ³ ) ^1/3 is 120 nm or less. More preferably (X ³ + Y ³ ) ^1/3 is 70 nm or less (X). ³ + Y ³ ) When ^1/3 is 1 nm or more, it is preferable because the transparent conductive film has some surface protrusions and can maintain the film winding property.

It is preferable that the transparent conductive film in the present invention does not peel off even when the adhesion test (JIS K5600-5-6: 1999) is carried out on the transparent conductive film surface. The transparent conductive film that does not peel off in the adhesion test is a transparent conductive film that is in close contact with a layer that is in contact with the transparent conductive film, such as a transparent plastic substrate or a curable resin layer. Even if continuous input is performed, cracks, peeling, wear, etc. are suppressed on the transparent conductive film, and even if a stronger force than expected for normal use is applied, cracks, peeling, etc. are suppressed on the transparent conductive film. preferable.

The transparent conductive film in the present invention is cracked or peeled when a bending resistance test (JIS K5600-5: 1: 1999) is performed on the transparent conductive film side of the transparent conductive film and the bent portion is observed with a 10-fold loupe. It is preferable that the mandrel diameter at which this occurs is smaller than 20 mm. When the mandrel diameter is smaller than 20 mm, the layer in contact with the transparent conductive film does not crack when the pen heavy pressure test is performed, and the transparent conductive film does not crack, which is preferable. More preferably, it is 18 mm or less.
In one embodiment, the value of the bending resistance test may be 1 mm or more, for example, 8 mm or more and 10 mm or more. Further, in one embodiment, the value of the bending resistance test is 13 mm or more, and may be 15 mm or more.
Within such a range, the layer in contact with the transparent conductive film does not crack when the pen heavy pressure test is performed, and the transparent conductive film does not crack, which is preferable.
Further, it becomes possible to provide a transparent conductive film having both excellent pen sliding durability and excellent pen heavy pressure durability.

In the transparent conductive film in the present invention, the thickness of the transparent plastic film base material is preferably in the range of 100 to 250 μm, more preferably 130 to 220 μm. When the thickness of the plastic film is 100 μm or more, the mechanical strength is maintained, the deformation with respect to the pen input when used for a touch panel is small, and the pen sliding durability and the pen heavy pressure durability are excellent, which is preferable. On the other hand, when the thickness is 250 μm or less, when it is used for a touch panel, it is not necessary to particularly increase the load for positioning by pen input, which is preferable.

The transparent conductive film in the present invention preferably has a curable resin layer between the transparent conductive film and the plastic film base material. The presence of the curable resin layer can increase the adhesion of the transparent conductive film and disperse the force applied to the transparent conductive film, so that cracks, peeling, wear, etc. are suppressed with respect to the transparent conductive film in the pen sliding test. Further, it is preferable because cracks and peeling are suppressed with respect to the transparent conductive film in the pen heavy pressure test.

The crystallinity of the transparent conductive film in the present invention is neither too high nor too low (such crystallinity is referred to as semi-crystalline or semi-crystalline). It is very difficult to make the transparent conductive film stable and semi-crystalline. This is because the state of being stopped in the middle of the rapid phase change from amorphous to crystalline is semi-crystalline. Therefore, it is sensitive to the amount of water in the film-forming atmosphere, which is a parameter related to crystallinity, and in particular, it is very sensitive to the hydrogen atom-containing gas, and if the amount of hydrogen atom-containing gas and water in the film-forming atmosphere is small, It becomes almost completely crystalline (high crystalline), and conversely, if there is a large amount of hydrogen atom-containing gas or water content in the film-forming atmosphere, it becomes amorphous (low crystalline).

The production method for obtaining the transparent conductive film of the present invention is not particularly limited, and for example, the following production methods can be preferably exemplified.
The sputtering method is preferably used as a method for forming a transparent conductive film of a crystalline indium-tin composite oxide on at least one surface of a transparent plastic film substrate. In order to produce a transparent conductive film with high productivity, it is preferable to use a so-called roll-type sputtering apparatus in which a film roll is supplied, and after film formation, the film is wound into the shape of the film roll. The hydrogen atom-containing gas (hydrogen, ammonia, hydrogen + argon mixed gas, etc., which is not particularly limited as long as it contains hydrogen atoms, but water is excluded) is described below by the mass flow controller in the film forming atmosphere. Indium-tin composite oxide using a sintered target of indium-tin composite oxide containing 0.5 to 10% by mass of tin oxide, with the film temperature during sputtering set to 0 ° C. or lower. The thickness of the transparent conductive film is adjusted to be 10 to 30 nm, and the transparent conductive film is placed on a transparent plastic film having a three-dimensional surface roughness SRa of the transparent conductive film of indium-tin composite oxide of 1 to 100 nm. It is preferable to form a film. The hydrogen atom-containing gas has the effect of inhibiting the crystallization of the transparent conductive film in the film forming atmosphere during sputtering. When hydrogen gas is flowed in the film forming atmosphere, the value of (hydrogen gas flow rate) ÷ (inert gas flow rate + hydrogen gas flow rate) × 100 (may be simply described as hydrogen concentration) is 0.01 to 3. It is desirable that it is 0.00%. The hydrogen concentration is, for example, 0.01% or more and 2.00%, and may be 0.01% or more and 1.00% or less.
When the hydrogen concentration is within such a range, it can contribute to leading to good results in both the pen sliding durability test ON resistance value and the pen heavy pressure durability test, for example.
Examples of the inert gas include helium, neon, argon, krypton, xenon and the like. When a hydrogen atom-containing gas other than hydrogen gas is used, the amount of hydrogen atom contained in the hydrogen atom-containing gas may be converted into the amount of hydrogen gas (= hydrogen molecule) for calculation. A gas outlet is arranged so that the hydrogen atom-containing gas can be sprayed uniformly in the direction perpendicular to the longitudinal direction of the film roll when the hydrogen atom-containing gas is precisely flowed in the film formation atmosphere by the mass flow controller. By doing so, it is difficult to form a transparent conductive film in which high and low crystalline parts are mixed, and it is easy to obtain a uniform semi-crystalline transparent conductive film. Therefore, excellent pen sliding durability and pen heavy pressure are applied. It is possible to suitably obtain a transparent conductive film having durability. Since it is known that the crystallinity of the transparent conductive film deteriorates when there is a large amount of water in the film-forming atmosphere, the amount of water in the film-forming atmosphere is also an important factor. When a hydrogen atom-containing gas is used, the center value (the value between the maximum value and the minimum value) of the ratio of the water pressure to the inert gas in the film formation atmosphere at the time of sputtering onto a film roll is 1.0 × 10. Controlled to ^-4 to 2.0 × 10 ^-3 , and the difference between the maximum and minimum values of the ratio of the water pressure to the inert gas in the film formation atmosphere during sputtering from the start of film formation to the end of film formation. When is 1.0 × 10 ^-3 or less, the uniformity of the crystallinity of the transparent conductive film is maintained over the entire length of the film. In addition, the amount of water released from the film when forming a transparent conductive film is small, such as the following bombarding process and the following limitation of the height difference of the unevenness of the end face of the film roll, so that the amount of water is uniform over the entire length of the film. If it is released, precise control of the water content becomes unnecessary, which is preferable. However, the central value of the ratio of the water pressure to the inert gas depends somewhat on the content of tin oxide in the transparent conductive film of the indium-tin composite oxide and the thickness of the transparent conductive film. When the amount of tin oxide added to the transparent conductive film of the indium-tin composite oxide is large or the transparent conductive film is thin, the center value of the ratio of the water pressure to the inert gas is set low within the above range. It is desirable to do. On the contrary, when the content of tin oxide in the transparent conductive film of the indium-tin composite oxide is low or the transparent conductive film is thick, the center value of the ratio of the water pressure to the inert gas is within the above range. It is desirable to set it higher. It is preferable to set the film temperature during sputtering to 0 ° C. or lower to form a transparent conductive film on the transparent plastic film. The film temperature during film formation is substituted by the set temperature of the temperature controller that adjusts the temperature of the center roll that the traveling film comes into contact with. Here, FIG. 5 shows a schematic diagram of an example of a sputtering apparatus preferably used in the present invention, in which the traveling film 1 partially contacts the surface of the center roll 2 and travels. An indium-tin sputtering target 4 is installed via the chimney 3, and a thin film of indium-tin composite oxide is deposited and laminated on the surface of the film 1 running on the center roll 2. The temperature of the center roll 2 is controlled by a temperature controller (not shown). When the film temperature is 0 ° C. or lower, the release of impurity gases such as water and organic gas from the film, which disperses the crystallinity of the transparent conductive film, can be suppressed, so that the film is transparent from the start of film formation to the end of film formation. It is preferable because the crystallinity of the conductive film is easily made uniform. When a hydrogen atom-containing gas is used, the center value of the ratio of the water pressure to the inert gas in the film forming atmosphere during sputtering (the value between the maximum value and the minimum value) is 1.0 × 10 ^-4 to 2 It is desirable that it is 0.0 × 10 ^-3 . When the ratio of the water pressure to the inert gas in the film forming atmosphere during sputtering is in the above range, it is desirable because the inhibition of the crystallinity of the transparent conductive film by the hydrogen atom-containing gas effectively acts. In addition, it is desirable to add oxygen gas during sputtering in order to bring the surface resistance and total light transmittance of the transparent conductive film to a practical level. The main purpose of this manufacturing method is to eliminate the influence of water-induced crystallinity, which is a factor that disperses the crystallinity of the transparent conductive film, as much as possible, and to control the crystallinity with a hydrogen-containing gas.

In order to control the water content when forming an indium-tin composite oxide on a plastic film, it is better to actually observe the water content at the time of film formation than to observe the ultimate vacuum degree. Desirable for one reason.

The first reason is that when a film is formed on a plastic film by sputtering, the film is heated and water is released from the film, so that the amount of water in the film formation atmosphere increases and the ultimate vacuum is measured. Since it increases more than the amount of water at the time, it is more accurate to express it with the amount of water at the time of film formation than to express it with the degree of ultimate vacuum.

The second reason is the case of a device that puts in a large amount of transparent plastic film. In such a device, the film is charged in the form of a film roll. When the film is rolled into a vacuum chamber, water easily drains from the outer layer of the roll, but water does not easily drain from the inner layer of the roll. When measuring the ultimate vacuum, the film roll is stopped, but the film roll runs during film formation, and the inner layer of the film roll containing a large amount of water is unwound, so that the moisture in the film formation atmosphere This is because the amount increases and the amount of water increases from the amount of water when the ultimate vacuum degree is measured. In the present invention, when controlling the amount of water in the film-forming atmosphere, it is possible to preferably cope with it by observing the ratio of the water pressure to the inert gas in the film-forming atmosphere during sputtering.

It is desirable to pass the film through the bombard process before forming the transparent conductive film. The bombarding step is to generate plasma by applying a voltage and discharging with only an inert gas such as argon gas or a mixed gas of a reactive gas such as oxygen and an inert gas flowing. .. Specifically, it is desirable to bombard the film by RF sputtering with a SUS target or the like. Since the film is exposed to plasma by the bombarding process, water and organic components are released from the film, and the amount of water and organic components released from the film when forming a transparent conductive film is reduced, so that the film is formed from the start of film formation. It is preferable because the crystallinity of the transparent conductive film up to the end is easily made uniform. Further, since the layer in contact with the transparent conductive film is activated by the bombard process, the adhesion of the transparent conductive film is improved, which is desirable because the pen sliding durability and the pen heavy pressure durability are improved.

The film roll for forming a transparent conductive film preferably has a height difference of 10 mm or less between the most convex portion and the most concave portion on the roll end face. If it is 10 mm or less, the crystal of the transparent conductive film from the start of film formation to the end of film formation will be less uneven in the way water and organic components are discharged from the end face of the film when the film roll is put into the sputtering apparatus. It is preferable because the properties are easily made uniform.

In the method of forming a transparent conductive film of a crystalline indium-tin composite oxide on at least one surface of a transparent plastic film substrate, it is desirable to introduce oxygen gas during sputtering. When oxygen gas is introduced during sputtering, there is no problem due to lack of oxygen in the transparent conductive film of the indium-tin composite oxide, the surface resistance of the transparent conductive film is low, and the total light transmittance is high, which is preferable. Therefore, it is desirable to introduce oxygen gas during sputtering in order to bring the surface resistance and total light transmittance of the transparent conductive film to a practical level. The total light transmittance of the transparent conductive film of the present invention is preferably 70 to 95%.

The transparent conductive film of the present invention is formed by laminating a transparent conductive film of an indium-tin composite oxide on a transparent plastic film substrate, and then in an atmosphere containing oxygen at 80 to 200 ° C. and 0.1 to 1. It is desirable that it has been heat-treated for 12 hours. When the temperature is 80 ° C. or higher, it is easy to take measures to slightly increase the crystallinity so as to make the pen semi-crystalline state, and the pen sliding durability is improved, which is preferable. When the temperature is 200 ° C. or lower, the flatness of the transparent plastic film is ensured, which is preferable.

<Transparent plastic film base material>
The transparent plastic film base material used in the present invention is a film obtained by melt-extruding or solution-extruding an organic polymer into a film, and if necessary, stretching, cooling, and heat-fixing in the longitudinal direction and / or the width direction. The organic polymers include polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthalate, polypropylene terephthalate, polybutylene terephthalate, nylon 6, nylon 4, nylon 66, nylon 12, polyimide, polyamideimide, and polyether. Sulfane, polyether ether ketone, polycarbonate, polyarylate, cellulose propionate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyetherimide, polyphenylene sulfide, polyphenylene oxide, polystyrene, syndiotactic polystyrene, norbornene polymer, etc. Can be mentioned.

Among these organic polymers, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, syndiotactic polystyrene, norbornene-based polymer, polycarbonate, polyarylate and the like are suitable. Further, these organic polymers may be copolymerized with a small amount of a monomer of another organic polymer, or may be blended with another organic polymer.

The transparent plastic film substrate used in the present invention has surface activity of the film such as corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, ozone treatment, etc., as long as the object of the present invention is not impaired. It may be subjected to a chemical discharge treatment.

When the curable resin layer is applied to the transparent plastic film base material, the transparent conductive film adheres strongly to the curable resin layer and the force applied to the transparent conductive film can be dispersed. It is preferable because cracks, peeling, abrasion, etc. are suppressed with respect to the film, and cracks, peeling, etc. are suppressed with respect to the transparent conductive film in the pen heavy pressure test. Further, when a transparent conductive film is formed on the surface of the curable resin layer having an uneven surface, the true contact area when the transparent conductive thin film comes into contact with the glass during the pen sliding test is reduced, so that the glass surface is reduced. It can be expected that the slipperiness between the transparent conductive film and the transparent conductive film will be improved and the pen sliding durability will be improved, the winding property of the film roll will be improved, and the anti-Newton ring property will be improved. This is not preferable because the amount of deformation of the surface protrusions when the pen heavy pressure test is performed becomes large and cracks occur in the transparent conductive film. Therefore, when the three-dimensional surface roughness SRa of the transparent conductive film is X as the surface unevenness, it is preferable that X is 1 to 100 nm. Further, the curable resin layer may be applied to both surfaces of the transparent plastic film base material. When the three-dimensional surface roughness SRa of the curable resin layer on the surface opposite to the surface on which the transparent conductive film is formed is Y, it is preferable that Y is 1 to 139 nm. Details of the curable resin layer are described below.

The curable resin preferably used in the present invention is not particularly limited as long as it is a resin that can be cured by applying energy such as heating, ultraviolet irradiation, electron beam irradiation, etc., and is a silicone resin, an acrylic resin, a methacrylic resin, or an epoxy resin. , Melamine resin, polyester resin, urethane resin and the like. From the viewpoint of productivity, it is preferable to use an ultraviolet curable resin as a main component.

Such an ultraviolet curable resin is synthesized from, for example, a polyfunctional acrylate resin such as acrylic acid or methacrylic acid ester of polyhydric alcohol, diisocyanate, polyhydric alcohol and hydroxyalkyl ester of acrylic acid or methacrylic acid. Examples thereof include a polyfunctional urethane acrylate resin and the like. If necessary, monofunctional monomers such as vinylpyrrolidone, methylmethacrylate, and styrene can be added to these polyfunctional resins to copolymerize them.

Further, in order to improve the adhesive force between the transparent conductive thin film and the curable resin layer, it is effective to treat the surface of the curable resin layer by the method described below. Specific methods include a discharge treatment method in which a glow or corona discharge is applied to increase the number of carbonyl groups, carboxyl groups, and hydroxyl groups, and an acid or alkali to increase polar groups such as amino groups, hydroxyl groups, and carbonyl groups. Examples include a chemical treatment method for processing.

The ultraviolet curable resin is usually used by adding a photopolymerization initiator. As the photopolymerization initiator, a known compound that absorbs ultraviolet rays to generate radicals can be used without particular limitation, and such photopolymerization initiators include, for example, various benzoins, phenylketones, and benzophenones. The kind etc. can be mentioned. The amount of the photopolymerization initiator added is usually preferably 1 to 5 parts by mass per 100 parts by mass of the ultraviolet curable resin.

Further, in the present invention, it is preferable to use inorganic particles and organic particles in combination with the curable resin layer, which is the main constituent component, in the curable resin layer. By dispersing the inorganic particles and organic particles in the curable resin, unevenness can be formed on the surface of the curable resin, and the surface roughness in a wide region can be improved.

Examples of the inorganic particles include silica and the like. Examples of the organic particles include polyester resin, polyolefin resin, polystyrene resin, and polyamide resin.

In addition to the inorganic particles and organic particles, it is also preferable to use a resin that is incompatible with the curable resin in combination with the curable resin that is the main component. By using a small amount of an incompatible resin in combination with the curable resin of the matrix, phase separation occurs in the curable resin and the incompatible resin can be dispersed in the form of particles. The dispersed particles of the incompatible resin can form irregularities on the surface of the curable resin and improve the surface roughness in a wide area.

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

Here, as an example, the mixing ratio when inorganic particles are used in the curable resin layer directly under the transparent conductive film is shown. The amount of the inorganic particles is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and particularly preferably 0.1 to 12 parts by mass per 100 parts by mass of the ultraviolet curable resin. When the blending amount is 0.1 to 20 parts by mass per 100 parts by mass of the ultraviolet curable resin, the convex portions formed on the surface of the curable resin layer are not too small, and three-dimensional surface roughness can be effectively imparted. When the pen heavy pressure test is performed, the amount of deformation of the surface protrusions is reduced, cracks in the transparent conductive film are suppressed, high-definition images can be provided, and the transparent conductive film has some surface protrusions, so the film is wound. It is preferable because it can maintain the removability.

Here, as an example, the blending ratio when inorganic particles are used in the curable resin layer on the surface opposite to the surface on which the transparent conductive film is formed is shown. The amount of the inorganic particles is preferably 0.1 to 25 parts by mass, more preferably 0.1 to 15 parts by mass, and particularly preferably 0.1 to 12 parts by mass per 100 parts by mass of the ultraviolet curable resin. When the blending amount is 0.1 to 25 parts by mass per 100 parts by mass of the ultraviolet curable resin, the convex portions formed on the surface of the curable resin layer are not too small, and three-dimensional surface roughness can be effectively imparted. It is preferable because it is possible to provide a high-definition image and the film winding property can be maintained because the transparent conductive film has some surface protrusions.

The above-mentioned ultraviolet curable resin, photopolymerization initiator, and resin incompatible with inorganic particles, organic particles, and ultraviolet curable resin are dissolved in a common solvent to prepare a coating liquid. The solvent used is not particularly limited, and is, for example, an alcohol solvent such as ethyl alcohol and isopropyl alcohol, an ester solvent such as ethyl acetate and butyl acetate, and dibutyl ether and ethylene glycol monoethyl ether. Ketone-based solvents such as ether-based solvents, methylisobutylketone, cyclohexanone and the like, aromatic hydrocarbon-based solvents such as toluene, xylene, solventnaphtha and the like can be used alone or in combination.

The concentration of the resin component in the coating liquid can be appropriately selected in consideration of the viscosity and the like according to the coating method. For example, the ratio of the total amount of the ultraviolet curable resin, the photopolymerization initiator, and the high molecular weight polyester resin in the coating liquid is usually 20 to 80% by mass. Further, other known additives such as a silicone-based leveling agent may be added to the coating liquid, if necessary.

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

The solvent of the coated coating liquid is evaporated and removed in the next drying step. In this step, the high molecular weight polyester resin uniformly dissolved in the coating liquid becomes particles and precipitates in the ultraviolet curable resin. After the coating film is dried, the plastic film is irradiated with ultraviolet rays to crosslink and cure the ultraviolet curable resin to form a curable resin layer. In this curing step, the high-molecular-weight polyester resin particles are fixed in the hard coat layer, and protrusions are formed on the surface of the curable resin layer to improve the surface roughness in a wide area.

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

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. The various measurements and evaluations in the examples were performed by the following methods.
(1) Total light transmittance The total light transmittance was measured using NDH-2000 manufactured by Nippon Denshoku Kogyo Co., Ltd. in accordance with JIS-K7136-1: 1997.

(2) Surface resistance value Measured by the 4-terminal method in accordance with JIS-K7194: 1994. As a measuring machine, Rotesta AX MCP-T370 manufactured by Mitsubishi Chemical Analytec Co., Ltd. was used.

(3) Three-dimensional center surface average surface roughness SRa
The three-dimensional center surface average surface roughness SRa is defined in ISO 25178, and is a three-dimensional surface shape measuring device Bartscan (R5500H-M100 manufactured by Ryoka System Co., Ltd. (measurement conditions: wave mode, measurement wavelength 560 nm,). The three-dimensional center plane average surface roughness SRa was obtained using an objective lens 10 times)). The number of measurements was set to 5, and the average value thereof was calculated. Here, the first decimal place in nm is rounded off. Here, the three-dimensional surface roughness SRa of the transparent conductive film is X, and the three-dimensional surface roughness SRa of the surface of the transparent plastic film substrate opposite to the transparent conductive film side is Y.

(4) Crystal grain size A film sample piece on which a transparent conductive thin film layer was laminated was cut into a size of 1 mm × 10 mm and attached to the upper surface of an appropriate resin block with the conductive thin film surface facing outward. After trimming this, an ultrathin section almost parallel to the film surface was prepared by a general ultramicrotome technique.
This section was observed with a transmission electron microscope (JEM-2010, manufactured by JEOL Ltd.), a conductive thin film surface portion having no significant damage was selected, and photographs were taken at an acceleration voltage of 200 kV and a direct magnification of 40,000 times.
In the crystal grains observed under a transmission electron microscope, the longest part of all the crystal grains is measured, and the average value of those measured values is taken as the crystal grain size. Here, FIGS. 1 to 4 show an example of a method for certifying the longest part of a crystal grain at the time of measurement. That is, the longest part is certified by the length of the straight line that can measure the largest particle size of each crystal grain.

(5) Thickness (film thickness) of transparent conductive film
A film sample piece on which a transparent conductive thin film layer was laminated was cut into a size of 1 mm × 10 mm and embedded in an epoxy resin for an electron microscope. This was fixed to the sample holder of the ultramicrotome, and a thin section having a cross section parallel to the short side of the embedded sample piece was prepared. Next, a photograph was taken at a site where the thin film of this section was not significantly damaged, using a transmission electron microscope (JEM-2010, manufactured by JEOL) at an acceleration voltage of 200 kV and a bright field of view at an observation magnification of 10,000 times. The film thickness was calculated from the photographs taken.

(6) Pen Sliding Durability Test The transparent conductive film according to the present invention is used as one panel plate, and the other panel plate is an indium-tin composite oxide thin film having a thickness of 20 nm on a glass substrate by a sputtering method. A transparent conductive thin film having a tin oxide content (10% by mass) was used. A touch panel was produced by arranging these two panel plates via epoxy beads having a diameter of 30 μm so that the transparent conductive thin films face each other. Next, a load of 5.0 N was applied to a polyacetal pen (tip shape: 0.8 mmR), and a linear sliding test of 180,000 reciprocations was performed on the touch panel. In this test, a pen load is applied to the transparent conductive film surface according to the present invention. At this time, the sliding distance was 30 mm and the sliding speed was 180 mm / sec. After this sliding durability test, the ON resistance (resistance value when the movable electrode (film electrode) and the fixed electrode came into contact with each other) when the sliding portion was pressed with a pen load of 0.8 N was measured. The ON resistance is preferably 10 kΩ or less.
In the comparative examples, the films in each comparative example were used instead of the transparent conductive film according to the present invention.

(7) Pen Heavy Pressurization Test A transparent conductive film obtained by cutting the transparent conductive film according to the present invention into a size of 50 mm × 50 mm is used as one panel plate, and the thickness of the other panel plate is increased by sputtering on a glass substrate. A transparent conductive thin film made of a 20 nm indium-tin oxide composite oxide thin film (tin oxide content: 10% by mass) was used. The two panel plates are arranged via epoxy beads having a diameter of 30 μm so that the transparent conductive thin films face each other, and the thickness is adjusted to 120 μm with double-sided tape. The panel plate on the film side and the panel on the glass side. A touch panel was made by pasting a board. A load of 35 N is applied to a position 2.0 mm from the end of the double-sided tape with a pen made of polyacetal (tip shape 0.8 mmR), and linear sliding is performed 10 times (5 reciprocations) in parallel with the double-sided tape. In this test, a pen load is applied to the transparent conductive film surface according to the present invention. At this time, the sliding distance is 30 mm and the sliding speed is 20 mm / sec. However, sliding is performed at a position where there are no epoxy beads. After sliding, the transparent conductive film is removed, the surface resistance (4 terminal method) at any 5 points of the sliding part is measured, and the average value is calculated. When measuring the surface resistance, arrange the four terminals in a direction perpendicular to the sliding portion so that the sliding portion comes between the second terminal and the third terminal. The rate of increase in the surface resistance value is calculated by dividing the average value of the surface resistance values of the sliding portion by the surface resistance value of the non-sliding portion (measured by the 4-terminal method).
In the comparative examples, the films in each comparative example were used instead of the transparent conductive film according to the present invention.

(8) Measurement of the content of tin oxide contained in the transparent conductive film Cut a sample (about 15 cm ² ), put it in a quartz Erlenmeyer flask, add 20 ml of 6 mol / l hydrochloric acid, and seal the film so that the acid does not volatilize. Did. It was left at room temperature for 9 days with occasional shaking to dissolve the transparent conductive film. The remaining film was taken out, and hydrochloric acid in which the transparent conductive film was dissolved was used as a measuring solution. In and Sn in the solution were determined by a calibration curve method using an ICP emission spectrometer (manufacturer name; Rigaku, device model; CIROS-120 EOP). For the measurement wavelength of each element, a wavelength with high sensitivity without interference was selected. As the standard solution, a commercially available standard solution of In and Sn was diluted and used.

(9) Adhesion test Conducted in accordance with JIS K5600-5-6: 1999.

(10) Flexibility test Performed in accordance with JIS K5600-5: 1: 1999. However, if cracking or peeling does not occur up to a mandrel diameter of 13 mm, no further bending resistance test is performed, and all are described as 13 mm.

(11) Transmission image sharpness test According to JIS-K7105, the transmission image sharpness of the transparent conductive film at comb widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm is measured. , The total of the transmission image sharpness of each comb width was calculated. As the measuring machine, the image quality measuring device ICM-1T manufactured by Suga Test Instruments Co., Ltd. was used.

The transparent plastic film base material used in Examples and Comparative Examples is a biaxially oriented transparent PET film having easy-adhesive layers on both sides (manufactured by Toyobo Co., Ltd., A4340, thickness is shown in Table 1). As the curable resin layer, 100 parts by mass of a photopolymerization initiator-containing acrylic resin (Seika Beam (registered trademark) EXF-01J, manufactured by Dainichi Seika Kogyo Co., Ltd.) and silica particles (Snowtex ZL, manufactured by Nissan Chemical Co., Ltd.) are shown. Add the amount described in 1 and add a mixed solvent of toluene / MEK (8/2: mass ratio) as a solvent so that the solid content concentration becomes 50% by mass, and stir to uniformly dissolve the coating liquid. Prepared (this coating liquid is hereinafter referred to as coating liquid A). The prepared coating liquid was applied using a Meyer bar so that the thickness of the coating film was 5 μm. After drying at 80 ° C. for 1 minute, the coating film was cured by irradiating with ultraviolet rays (light intensity: 300 mJ / cm ² ) using an ultraviolet irradiation device (UB042-5AM-W type manufactured by Eye Graphics). .. Further, the curable resin layer was provided on both sides of the transparent plastic base material.

(Examples 1 to 8)
Each example level was carried out as follows under the conditions shown in Table 1.
The film was placed in a vacuum chamber and evacuated to 1.5 × 10 ^-4 Pa. Next, after the introduction of oxygen, argon was introduced as the inert gas and hydrogen gas was introduced as the hydrogen-containing gas at the concentrations shown in Table 1 to bring the total pressure to 0.6 Pa.
Power was applied to an indium-tin oxide composite oxide sintering target or an indium oxide sintered target containing no tin oxide at a power density of 3 W / cm ² , and a transparent conductive film was formed by a DC magnetron sputtering method. The film thickness was controlled by changing the speed at which the film passed over the target. The ratio of the water pressure to the inert gas in the film formation atmosphere during sputtering was measured using a gas analyzer (Transpector XPR3 manufactured by Inficon). At each example level, in order to adjust the ratio of the water pressure to the inert gas in the film formation atmosphere during sputtering, as shown in Table 1, the presence or absence of the bombard step, the unevenness height difference of the film roll end face, and the film The temperature of the temperature medium of the temperature controller that controls the temperature of the center roll traveling in contact was adjusted. Table 1 shows the temperature at the center of the maximum and minimum temperatures from the start of film formation to the end of film formation on the film roll as the center value.
The film on which the transparent conductive film was formed and laminated was subjected to the heat treatment shown in Table 1 and then measured. The measurement results are shown in Table 1.

(Comparative Examples 1 to 9)
A transparent conductive film was prepared and evaluated in the same manner as in Example 1 under the conditions shown in Table 1. However, Comparative Example 7 does not have a curable resin layer. However, in Comparative Example 8, the thickness of the coating film of the curable resin layer was adjusted to be 20 μm. The results are shown in Table 2.

As shown in Tables 1A and 1B, the transparent conductive films shown in Examples 1 to 8 are excellent in pen sliding durability, pen heavy pressure durability, and high definition, and have all the characteristics. There is. However, as shown in Table 2, Comparative Examples 1 to 9 cannot satisfy all of the pen sliding durability, the pen heavy pressure durability, and the high definition.

As described above, according to the present invention, a transparent conductive film having excellent pen sliding durability, pen heavy pressure durability, and high definition can be produced, which is extremely useful for applications such as a resistance film type touch panel. be.

1. 1. Film 2. Center roll 3. Chimney 4. Target of indium-tin composite oxide

Claims

A transparent conductive film in which a transparent conductive film of an indium-tin composite oxide is laminated on one surface of a transparent plastic film substrate, and is a transparent conductive film of the transparent conductive film according to the following pen sliding durability test. The ON resistance is 10 kΩ or less, the increase rate of the surface resistance value of the transparent conductive film of the transparent conductive film by the following pen heavy pressure test is 1.5 or less, and the comb widths are 0.125 mm, 0.25 mm, and 0. A transparent conductive film having a total transmission image sharpness of 2.5 mm, 1.0 mm, and 2.0 mm, which is 250% or more and less than 500%.
(Pen sliding durability test method)
The transparent conductive film is used as one panel plate, and the other panel plate is transparent composed of an indium-tin oxide composite oxide thin film (tin oxide content: 10% by mass) having a thickness of 20 nm on a glass substrate by a sputtering method. Use a conductive thin film. The two panel plates are arranged via epoxy beads having a diameter of 30 μm so that the transparent conductive thin films face each other, and the film side panel plate and the glass side panel plate are attached with double-sided tape having a thickness of 170 μm. , Make a touch panel. Next, a load of 2.5 N is applied to a polyacetal pen (tip shape: 0.8 mmR), and a linear sliding test of 180,000 reciprocations is performed on the touch panel. In this test, a pen load is applied to the transparent conductive film surface. At this time, the sliding distance is 30 mm and the sliding speed is 180 mm / sec. After this sliding durability test, the ON resistance (resistance value when the movable electrode (film electrode) and the fixed electrode come into contact with each other) when the sliding portion is pressed with a pen load of 0.8 N is measured.
(Pen heavy pressure test method)
The transparent conductive film cut to 50 mm × 50 mm is used as one panel plate, and the other panel plate is an indium-tin oxide composite oxide thin film having a thickness of 20 nm by a sputtering method on a glass substrate (tin oxide content: 10). A transparent conductive thin film consisting of (% by mass) is used. The two panel plates are arranged via epoxy beads having a diameter of 30 μm so that the transparent conductive thin films face each other, and the thickness is adjusted to 120 μm with double-sided tape. The panel plate on the film side and the panel on the glass side. A touch panel was made by pasting a board. A load of 35 N is applied to a position 2.0 mm from the end of the double-sided tape with a pen made of polyacetal (tip shape 0.8 mmR), and linear sliding is performed 10 times (5 reciprocations) in parallel with the double-sided tape. In this test, a pen load is applied to the transparent conductive film surface. At this time, the sliding distance is 30 mm and the sliding speed is 20 mm / sec. Slide in a position where there are no epoxy beads. After sliding, the transparent conductive film is removed, the surface resistance (4 terminal method) at any 5 points of the sliding part is measured, and the average value is calculated. When measuring the surface resistance, arrange the four terminals in a direction perpendicular to the sliding portion so that the sliding portion comes between the second terminal and the third terminal. The rate of increase in the surface resistance value is calculated by dividing the average value of the surface resistance values of the sliding portion by the surface resistance value of the non-sliding portion (measured by the 4-terminal method).
The crystal grain size of the transparent conductive film of the indium-tin composite oxide is 10 to 100 nm, the crystallinity of the transparent conductive film of the indium-tin composite oxide is 20 to 80%, and the crystal size of the transparent conductive film of the indium-tin oxide is 20 to 80%. The transparent conductive film contains 0.5 to 10% by mass of tin oxide, the thickness of the transparent conductive film of the indium-tin composite oxide is 10 to 30 nm, and the thickness of the transparent conductive film of the indium-tin composite oxide is three-dimensional. When the surface roughness SRa is X, X is 1 to 100 nm, and when the three-dimensional surface roughness SRa on the transparent conductive film substrate opposite to the transparent conductive film side is Y, (X 3 ). + Y 3 ) The transparent conductive film according to claim 1, wherein 1/3 is 140 nm or less.
Even if the adhesion test (JIS K5600-5-6: 1999) was performed on the surface of the transparent conductive film, the transparent conductive film did not peel off, and the transparent conductive film was resistant to the transparent conductive film side of the indium-tin composite oxide. The transparent conductivity according to claim 1 or 2, wherein the mandrel diameter is smaller than 20 mm, in which cracking or peeling occurs when a bending portion is observed by a bending test (JIS K5600-5: 1: 1999) with a 10-fold loupe. the film.
The transparent conductive film according to any one of claims 1 to 3, wherein the thickness of the transparent conductive film is 100 to 250 μm.
The transparent conductive film according to any one of claims 1 to 4, which has a curable resin layer between the transparent conductive film of the indium-tin composite oxide and the transparent plastic film substrate.