JP7272488B2 - transparent conductive film - Google Patents

Description

The present invention relates to a transparent conductive film obtained by laminating a transparent conductive film of a crystalline indium-tin composite oxide on a transparent plastic film substrate, in particular, pen sliding durability when used in a resistive touch panel, pen The present invention relates to a transparent conductive film excellent in durability under heavy pressure and environmental stability.

Transparent conductive films, which are made by laminating a transparent and low-resistance thin film on a transparent plastic substrate, are used in applications that make use of their conductivity, such as flat panel displays such as liquid crystal displays and electroluminescence (EL) displays. It is widely used in the electrical and electronic fields as a transparent electrode for touch panels, etc.

A resistive touch panel is a combination of a fixed electrode made by coating a transparent conductive thin film on a glass or plastic substrate and a movable electrode (= film electrode) made by coating a transparent conductive thin film on a plastic film. It is used overlaid on top. Pressing the film electrode with a finger or a pen to bring the transparent conductive thin films of the fixed electrode and the film electrode into contact with each other serves as an input for recognizing the position of the touch panel.

For example, as a means for improving pen sliding durability, there is a method of making the transparent conductive thin film on the film electrode side crystalline (see Patent Document 1).

Japanese Patent Application Laid-Open No. 2004-071171

A conventional transparent conductive film disclosed in Patent Document 1 attempts to improve pen sliding durability by controlling the crystallinity of an indium-tin composite oxide. However, conventional transparent conductive films were insufficient in the pen heavy pressure durability test described below. In addition, in recent years, the applications of resistive touch panels have been diversifying, and there is a demand for further improvement in pen sliding durability.

In many cases, a pen exerts a stronger force on a touch panel than a finger. If the pen continues to be used to input information to the touch panel, the transparent conductive thin film on the film electrode side may be damaged by cracks, peeling, abrasion, or the like. In addition, if a force stronger than expected for normal use is applied to the touch panel, such as striking the touch panel with a pen or pen input with a very strong force, the transparent conductive thin film may be cracked, peeled off, or otherwise destroyed.
In order to solve these problems, there is a demand for a transparent conductive film that achieves both excellent pen sliding durability and excellent pen heavy pressure durability. Furthermore, there is a demand for a transparent conductive film that can operate as a resistive touch panel without problems even under severe environments such as high-temperature, high-humidity conditions and high-temperature conditions.

In view of the above-mentioned conventional problems, the object of the present invention is to provide a transparent conductive material having excellent pen sliding durability when used in a touch panel, excellent pen heavy pressure durability, and excellent environmental stability. to provide the film.

The present invention has been made in view of the above circumstances, and the transparent conductive film of the present invention, which has solved the above problems, has the following configuration.
[1] A 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 base material, and has a total light transmittance of 70 to 95%. The ON resistance of the transparent conductive film of the transparent conductive film in the pen sliding durability test is 10 kΩ or less,
The increase rate of the surface resistance value of the transparent conductive film of the transparent conductive film in the following pen heavy pressure test is 1.5 or less,
The environmental stability evaluation value ES ₆₀ represented by the following formula 1 is 0.5 or more and 1.5 or less, and
Environmental stability evaluation value ES ₉₀ represented by the following formula 2 is 0.5 or more and 1.5 or less,
Transparent conductive film.
(Pen sliding durability test method)
Using the transparent conductive film according to the present invention as one panel plate, and as the other panel plate, an indium-tin composite oxide thin film having a thickness of 20 nm (tin oxide content: 10% by mass) was formed on a glass substrate by a sputtering method. A transparent conductive thin film consisting of The two panel plates are arranged so that the transparent conductive thin films face each other with epoxy beads having a diameter of 30 μm interposed therebetween, and the panel plate on the film side and the panel plate on the glass side are attached with double-sided tape having a thickness of 170 μm. , to produce a touch panel. Next, a linear sliding test of 180,000 reciprocations is performed on the touch panel by applying a load of 2.5 N to a pen made of polyacetal (tip shape: 0.8 mmR). In this test, a pen load is applied to the surface of the transparent conductive film according to the present invention.
The sliding distance at this time 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 are in contact) is measured when the sliding portion is pressed with a pen load of 0.8N.
(Pen heavy pressure test method)
A transparent conductive film according to the present invention cut to 50 mm × 50 mm was used as one panel plate, and as the other panel plate, an indium-tin composite oxide thin film (tin oxide content: 10% by mass). These two panel plates are arranged so that the transparent conductive thin films face each other, with epoxy beads having a diameter of 30 μm interposed therebetween. A touch panel was produced by pasting the plates. A polyacetal pen (tip shape 0.8 mmR) is applied at a position 2.0 mm from the end of the double-sided tape with a load of 35 N, and the double-sided tape is linearly slid 10 times (5 times reciprocating) parallel to the double-sided tape. In this test, a pen load is applied to the surface of the transparent conductive film according to the present invention. The sliding distance at this time is 30 mm, and the sliding speed is 20 mm/sec. Sliding is performed at the position where there is no epoxy bead. After sliding, remove the transparent conductive film, measure the surface resistance (four-probe method) at any five locations on the sliding portion, and calculate the average value. When measuring the surface resistance, align the four terminals in a direction perpendicular to the sliding part so that the sliding part is between the second and third terminals. The increase rate of the surface resistance is calculated by dividing the average value of the surface resistance of the sliding portion by the surface resistance of the non-sliding portion (measured by the 4-probe method).
(Environmental stability evaluation)
A transparent conductive film roll is cut to 100 mm in the longitudinal (MD) direction. The cut film is heat-treated at 165° C. for 75 minutes.
Let R ₁ S be the average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the heat-treated transparent conductive film, and the surface resistance at two points in the central region of the transparent conductive film. Let R _C S be the average value of the values, and let R ₂ S be the average value of the surface resistance values at two points in the second end region located on the opposite side of the first end region.
Next, the heat-treated transparent conductive film is further treated at 60° C. and 95% RH for 240 hours under high temperature and high humidity conditions. The average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the transparent conductive film treated at 60 ° C. 95% RH for 240 hours is defined as R ₁ aE, and in the central region of the transparent conductive film The average value of the surface resistance values at the two points is R _C aE, and the average value of the surface resistance values at the two points in the second end region located on the opposite side of the first end region is R ₂ aE. do.
Moreover, the transparent conductive film heat-treated at 165° C. for 75 minutes is further treated at 90° C. for 240 hours. The average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the transparent conductive film treated at 90 ° C. for 240 hours was defined as R ₁ bE, and the two points in the central region of the transparent conductive film. Let R _C bE be the average value of the surface resistance values of , and let R ₂ bE be the average value of the surface resistance values at two points in the second end region located on the opposite side of the first end region.
The value shown by the following formula 1 is the environmental stability evaluation value ES ₆₀ ,
Environmental stability evaluation value ES ₉₀ represented by the following formula 2 [(R ₁ aE/R ₁ S) + (R _C aE/R _C S) + (R ₂ aE/R ₂ S)]/3 ( Formula 1)
[(R ₁ bE/R ₁ S)+(R _C bE/R _C S)+(R ₂ bE/R ₂ S)]/3 (Formula 2)
[2] In one aspect of the transparent conductive film of the present invention, the transparent conductive film of the indium-tin composite oxide has a crystal grain size of 10 to 100 nm, and the transparent conductive film of the indium-tin composite oxide is crystallized. content is 20 to 80%, and the indium-tin composite oxide transparent conductive film contains 0.5 to 10% by mass of tin oxide.
[3] In one aspect of the transparent conductive film of the present invention, the transparent conductive film of the indium-tin composite oxide has a thickness of 10 to 30 nm, and the three-dimensional surface of the transparent conductive film of the indium-tin composite oxide is 3. The transparent conductive film according to claim 1, wherein the roughness SRa is 1 to 100 nm, and the thickness distribution in the width (TD) direction of the transparent conductive film is 5% or less.
(Evaluation of thickness distribution in width (TD) direction of transparent conductive film)
A transparent conductive film roll is cut 50 mm in the longitudinal (MD) direction. The thickness of the cut film is measured every 50 mm in the width (TD) direction from the extreme end of the width (TD) direction, and the thickness is measured to the opposite extreme end. Calculate the thickness distribution.
Also, the distance between the opposite end portion and the measurement site one point before it may be less than 50 mm.
[(maximum thickness of transparent conductive film) - (minimum thickness of transparent conductive film)]/(maximum thickness of transparent conductive film) x 100 (Formula 3)
[4] In one aspect of the transparent conductive film of the present invention, the transparent conductive film does not peel off even when an adhesion test (JIS K5600-5-6:1999) is performed on the surface of the transparent conductive film,
A flex resistance test (JIS K5600-5-1: 1999) was performed on the transparent conductive film side of the indium-tin composite oxide of the transparent conductive film, and when the flexed portion was observed with a magnifying glass of 10x magnification, no cracks or peeling occurred. The resulting mandrel diameter is less than 20 mm.
[5] In one aspect, the transparent conductive film of the present invention has a thickness of 100 to 250 μm.
[6] In one aspect, the transparent conductive film of the present invention has a curable resin layer between the transparent conductive film of the indium-tin composite oxide and the transparent plastic film substrate.

According to the present invention, excellent pen sliding durability and excellent pen heavy pressure durability are combined, and excellent environmental stability is achieved.

FIG. 2 is a schematic diagram showing an example (No. 1) of the longest part of a crystal grain in the present invention; FIG. 4 is a schematic diagram showing another example (No. 2) of the longest part of the crystal grains in the present invention. FIG. 3 is a schematic diagram showing another example (No. 3) of the longest part of a crystal grain in the present invention; FIG. 10 is a schematic diagram showing another example (No. 4) of the longest part of the crystal grains in the present invention. FIG. 2 is a schematic diagram for explaining the position of a center roll of an example of a sputtering apparatus preferably used in the present invention; It is a schematic diagram which shows an example of the test piece used for evaluation of environmental stability.

A transparent conductive film in which a transparent conductive film of indium-tin composite oxide is laminated on at least one surface of a transparent plastic film substrate, and the transparent conductive film of the transparent conductive film is subjected to a pen sliding durability test described later. has an ON resistance of 10 kΩ or less,
The increase rate of the surface resistance value of the transparent conductive film of the transparent conductive film in the pen heavy pressure test described later is 1.5 or less,
The environmental stability evaluation value ES ₆₀ represented by the following formula 1 is 0.5 or more and 1.5 or less, and
Environmental stability evaluation value ES ₉₀ represented by the following formula 2 is 0.5 or more and 1.5 or less,
Transparent conductive film.
(Environmental stability evaluation)
A transparent conductive film roll is cut to 100 mm in the longitudinal (MD) direction. The cut film is heat-treated at 165° C. for 75 minutes.
Let R ₁ S be the average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the heat-treated transparent conductive film, and the surface resistance at two points in the central region of the transparent conductive film. Let R _C S be the average value of the values, and let R ₂ S be the average value of the surface resistance values at two points in the second end region located on the opposite side of the first end region.
Next, the heat-treated transparent conductive film is further treated at 60° C. and 95% RH for 240 hours under high temperature and high humidity conditions. The average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the transparent conductive film treated at 60 ° C. 95% RH for 240 hours is defined as R ₁ aE, and in the central region of the transparent conductive film The average value of the surface resistance values at the two points is R _C aE, and the average value of the surface resistance values at the two points in the second end region located on the opposite side of the first end region is R ₂ aE. do.
Moreover, the transparent conductive film heat-treated at 165° C. for 75 minutes is further treated at 90° C. for 240 hours. The average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the transparent conductive film treated at 90 ° C. for 240 hours was defined as R ₁ bE, and the two points in the central region of the transparent conductive film. Let R _C bE be the average value of the surface resistance values of , and let R ₂ bE be the average value of the surface resistance values at two points in the second end region located on the opposite side of the first end region.
The value shown by the following formula 1 is the environmental stability evaluation value ES ₆₀ ,
Environmental stability evaluation value ES ₉₀ represented by the following formula 2 [(R ₁ aE/R ₁ S) + (R _C aE/R _C S) + (R ₂ aE/R ₂ S)]/3 ( Formula 1)
[(R ₁ bE/R ₁ S)+(R _C bE/R _C S)+(R ₂ bE/R ₂ S)]/3 (Formula 2)

The transparent conductive film of the present invention is excellent in pen sliding durability and pen heavy pressure durability. Moreover, it has excellent environmental stability. The obtained transparent conductive film is extremely useful for applications such as resistive touch panels.

Pen sliding durability and pen heavy pressure durability are contradictory properties. First, the pen sliding durability will be described. A transparent conductive film made of indium-tin composite oxide, which has excellent pen sliding durability, must have a high degree of crystallinity, a large crystal grain size, and a small three-dimensional surface roughness of the transparent conductive film. . Although the three-dimensional surface roughness will be explained later, the degree of crystallinity and the crystal grain size will be explained first. A portion having a circular or polygonal region observed under a transmission electron microscope is defined as a crystal (=crystal grain) of the transparent conductive film, and the other portion is defined as amorphous. A high degree of crystallinity indicates a high proportion of crystals. A large crystal grain size indicates 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 ratio of hard crystals, and a large crystal grain size causes a large strain around the crystal grains. Excellent for
According to the present invention, it has excellent sliding durability even for input with a pen, and the present invention that is arranged on the film electrode side even when continuously inputting with a pen on the touch panel In the transparent conductive thin film according to, breakage such as cracks, peeling, and abrasion can be suppressed.
The present invention, of course, can have excellent sliding durability even when a finger is used for input to the touch panel.

Next, pen heavy pressure durability will be described. The transparent conductive film of indium-tin composite oxide, which is excellent in pen heavy pressure durability, has a low degree of crystallinity and a small crystal grain size. A transparent conductive film with a low degree of crystallinity has a high percentage of soft amorphous, and a film with a small crystal grain size has less strain around the crystal grains. It is difficult to enter, and has excellent pen heavy pressure durability.
In many cases, a pen exerts a stronger force on a touch panel than a finger. According to the present invention, as described above, it has excellent pen heavy pressure durability even for input with a pen, and even if you continue to input with a pen on the touch panel, it is arranged on the film electrode side. In the transparent conductive thin film according to the present invention, damage such as cracks, peeling and abrasion can be suppressed.
The present invention, of course, can have excellent heavy pressure durability even in input to the touch panel with a finger.

As described above, it can be seen that pen sliding durability and pen heavy pressure durability are contradictory properties. As a result of investigation, the present inventors have found that by controlling the crystallinity and crystal grain size of the transparent conductive film, it is possible to achieve both pen sliding durability and pen heavy pressure durability.
Furthermore, the present invention can provide a transparent conductive film excellent in environmental stability. In particular, it is extremely useful for applications such as resistive touch panels.
Hereinafter, a transparent conductive film having a transparent conductive film that can achieve both pen sliding durability and pen heavy pressure durability and is excellent in environmental stability will be described.

(Pen sliding durability test method)
Using the transparent conductive film according to the present invention as one panel plate, and as the other panel plate, an indium-tin composite oxide thin film having a thickness of 20 nm (tin oxide content: 10% by mass) was formed on a glass substrate by a sputtering method. A transparent conductive thin film consisting of The two panel plates are arranged so that the transparent conductive thin films face each other with epoxy beads having a diameter of 30 μm interposed therebetween, and the panel plate on the film side and the panel plate on the glass side are attached with double-sided tape having a thickness of 170 μm. , to produce a touch panel. Next, a linear sliding test of 180,000 reciprocations is performed on the touch panel by applying a load of 2.5 N to a pen made of polyacetal (tip shape: 0.8 mmR). In this test, a pen load is applied to the surface of the transparent conductive film according to the present invention.
The sliding distance at this time 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 are in contact) is measured when the sliding portion is pressed with a pen load of 0.8N.

In the present invention, if the ON resistance of the transparent conductive film of the transparent conductive film in the pen sliding durability test is 10 kΩ or less, cracks, peeling, abrasion, etc. of the transparent conductive film can be suppressed even if the pen is continuously input to the touch panel. preferred because it is In one aspect, 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 preferably is 1 kΩ or less.
The ON resistance is preferably a smaller value, and may be, for example, 5 kΩ or more, or 3 kΩ or more. In one aspect, it is 0 kΩ or greater, and may be, for example, 0.05 kΩ or greater.
When the ON resistance is within such a range, cracks, peeling, abrasion, etc. of the transparent conductive film can be suppressed even when continuous input is made with a pen on the touch panel.
In one aspect, these upper and lower limits may be combined as appropriate.

(Pen heavy pressure test method)
A transparent conductive film according to the present invention cut to 50 mm × 50 mm was used as one panel plate, and as the other panel plate, an indium-tin composite oxide thin film (tin oxide content: 10% by mass). These two panel plates are arranged so that the transparent conductive thin films face each other, with epoxy beads having a diameter of 30 μm interposed therebetween. A touch panel was produced by pasting the plates. A polyacetal pen (tip shape 0.8 mmR) is applied at a position 2.0 mm from the end of the double-sided tape with a load of 35 N, and the double-sided tape is linearly slid 10 times (5 times reciprocating) parallel to the double-sided tape. In this test, a pen load is applied to the surface of the transparent conductive film according to the present invention. The sliding distance at this time is 30 mm, and the sliding speed is 20 mm/sec. Sliding is performed at the position where there is no epoxy bead. After sliding, remove the transparent conductive film, measure the surface resistance (four-probe method) at any five locations on the sliding portion, and calculate the average value. When measuring the surface resistance, align the four terminals in a direction perpendicular to the sliding part so that the sliding part is between the second and third terminals. The increase rate of the surface resistance is calculated by dividing the average value of the surface resistance of the sliding portion by the surface resistance of the non-sliding portion (measured by the 4-probe method).

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

In one aspect, the transparent conductive film has an ON resistance of 0.05 or more and 9.5 or less in the pen sliding durability test, and the transparent conductive film in 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 normally contradictory properties. In the present invention, these two durabilitys can be well-balanced within such a range. In addition, the transparent conductive film can be prevented from cracking, peeling, and wearing even if the pen is used for continuous input to the touch panel. can be shown. For the numerical range, the ranges and values described in this specification can be selected.

In the transparent conductive film of the present invention, it is preferred that the transparent conductive film does not peel off even when an adhesion test (JIS K5600-5-6:1999) is carried out on the transparent conductive film surface. The transparent conductive film does not peel off in the adhesion test. The transparent conductive film is in close contact with the transparent plastic base material, curable resin layer, and other layers that are in contact with the transparent conductive film. Cracking, peeling, and abrasion of the transparent conductive film are suppressed even with continuous input, and cracking and peeling of the transparent conductive film are suppressed even when a force stronger than expected for normal use is applied. preferable.

In the transparent conductive film of the present invention, the crystal grain size of the transparent conductive film of indium-tin composite oxide is 10 to 100 nm, and the crystallinity of the transparent conductive film of indium-tin composite oxide is 20 to 80%. Preferably. 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 strain around the crystal grains of the transparent conductive film, so that 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, if the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 100 nm or less, the transparent conductive film will not be too hard due to distortion around the crystal grains of the transparent conductive film, and pen heavy pressure durability will not be 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 aspect, the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 10 nm or more and 95 nm or less, for example, 30 nm or more and 90 nm or less. For example, it is 40 nm or more and 80 nm or less.
For example, the crystal grain size observed under a transmission electron microscope WHEREIN: The longest part of all the crystal grains is measured, and let the average value of those measured values be a crystal grain size. Here, FIGS. 1 to 4 show an example of a method for recognizing the longest part of a crystal grain when measuring the longest part.

When the crystallinity of the transparent conductive film of the indium-tin composite oxide is 20% or more, it is moderately hardened by the hard crystals occupying the transparent conductive film, and is excellent in pen sliding durability, which is preferable. More preferably, the crystallinity of the transparent conductive film of indium-tin composite oxide is 25% or more. On the other hand, if 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 the pen heavy pressure durability is excellent. Therefore, it is preferable.
In one aspect, 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 of the invention preferably has a three-dimensional surface roughness SRa of 1 to 100 nm. When the three-dimensional surface roughness SRa of the transparent conductive film 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 a pen heavy pressure test is performed, and the transparent conductive film is improved. It is preferable because the occurrence of cracks is suppressed and the film windability can be maintained because the transparent conductive film has some surface protrusions. More preferably, the three-dimensional surface roughness SRa of the transparent conductive film is 1-80 nm. More preferably, the three-dimensional surface roughness SRa of the transparent conductive film 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 impurities for indium oxide. The melting point of the indium-tin composite oxide increases due to the presence of tin oxide impurities. That is, the inclusion of impurities in tin oxide works to inhibit crystallization, and is therefore an important factor that has a strong correlation with crystallinity such as grain size and degree of crystallinity. When the tin oxide content is 0.5% by mass or more, the surface resistance of the transparent conductive film is at a practical level, which is preferable. More preferably, the content of tin oxide is 1% by mass or more, and particularly preferably 2% by mass or more. When the content of tin oxide is 10% by mass or less, crystallization is likely to occur when adjusting to a semi-crystalline state, which will be described later, and pen sliding durability is improved, which is preferable. The tin oxide content is more preferably 8% by mass or less, even more preferably 6% by mass or less, and particularly preferably 4% by mass or less. The transparent conductive film of the present invention preferably has a surface resistance of 50 to 900 Ω/square, more preferably 50 to 600 Ω/square.

In the present invention, the thickness of the transparent conductive film is preferably 10 nm or more and 30 nm or less. The thickness of the transparent conductive film is an important factor that has a strong correlation with crystallinity such as crystal grain size and degree of crystallinity. When the thickness of the transparent conductive film is 10 nm or more, the transparent conductive film does not have too much amorphous content, and it is easy to provide an appropriate crystal grain size and degree of crystallinity for the semi-crystalline state described later, and as a result, the pen slides. It is preferable because it maintains durability. More preferably, the thickness of the transparent conductive film is 13 nm or more, more preferably 16 nm or more. In addition, when the thickness of the transparent conductive film is 30 nm or less, the crystal grain size of the transparent conductive film is not too large and the degree of crystallinity is not too high, so that the semi-crystalline state can be easily maintained, and the pen heavy pressure durability can be maintained. It is preferable because it maintains the characteristics. It is more preferably 28 nm or less, still more preferably 25 nm or less.

The transparent conductive film of the present invention was subjected to a bending resistance test (JIS K5600-5-1: 1999) on the transparent conductive film side of the transparent conductive film, and when the bending portion was observed with a magnifying glass of 10 times, cracks and peeling occurred. Preferably, the mandrel diameter at which shear occurs is less than 20 mm. When the mandrel diameter is smaller than 20 mm, the layer in contact with the transparent conductive film does not break when pen heavy pressure test is performed, and cracks do not occur in the transparent conductive film, which is preferable. More preferably, it is 18 mm or less. In one embodiment, the bending resistance test value is, for example, 15 mm or more, may be 8 mm or more, and preferably is 1 mm or more.

In the transparent conductive film of the invention, the thickness of the transparent plastic film substrate is preferably in the range of 100 to 250 μm, more preferably 130 to 220 μm. When the thickness of the plastic film is 100 μm or more, the mechanical strength is maintained, the deformation against pen input when used in a touch panel is small, and the pen sliding durability and pen heavy pressure durability are excellent, which is preferable. On the other hand, when the thickness is 250 μm or less, when used in a touch panel, there is no need to 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 of the indium-tin composite oxide and the plastic film substrate.
The presence of the curable resin layer can increase the adhesive strength of the transparent conductive film and disperse the force applied to the transparent conductive film, so cracks, peeling, and abrasion of the transparent conductive film in the pen sliding test are suppressed. Furthermore, cracks and peeling of the transparent conductive film in a pen heavy pressure test are suppressed, which is preferable.

The crystallinity of the transparent conductive film in the present invention is neither too high nor too low (such crystallinity is called semi-crystalline or semi-crystalline). It is very difficult to stably make a transparent conductive film semicrystalline. This is because the semi-crystalline state is the state in which the abrupt phase change from amorphous to crystalline is halted. Therefore, it is sensitive to the amount of moisture in the film formation atmosphere, which is a parameter related to crystallinity, and is particularly sensitive to gases containing hydrogen atoms. It becomes almost completely crystalline (high crystallinity), and conversely, it becomes amorphous (low crystallinity) if there is even a small amount of hydrogen atom-containing gas or moisture in the film forming atmosphere.

The transparent conductive film of the present invention is a transparent conductive film in which a transparent conductive film of indium-tin composite oxide is laminated on at least one surface of a transparent plastic film substrate, and is represented by the following formula 1. Environmental stability evaluation value ES ₆₀ is 0.5 or more and 1.5 or less, and
Environmental stability evaluation value ES ₉₀ represented by the following formula 2 is 0.5 or more and 1.5 or less,
It is a transparent conductive film.
(Environmental stability evaluation)
A transparent conductive film roll is cut to 100 mm in the longitudinal (MD) direction. The cut film is heat-treated at 165° C. for 75 minutes.
Let R ₁ S be the average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the heat-treated transparent conductive film, and the surface resistance at two points in the central region of the transparent conductive film. Let R _C S be the average value of the values, and let R ₂ S be the average value of the surface resistance values at two points in the second end region located on the opposite side of the first end region.
Next, the heat-treated transparent conductive film is further treated at 60° C. and 95% RH for 240 hours under high temperature and high humidity conditions. The average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the transparent conductive film treated at 60 ° C. 95% RH for 240 hours is defined as R ₁ aE, and in the central region of the transparent conductive film The average value of the surface resistance values at the two points is R _C aE, and the average value of the surface resistance values at the two points in the second end region located on the opposite side of the first end region is R ₂ aE. do.
Moreover, the transparent conductive film heat-treated at 165° C. for 75 minutes is further treated at 90° C. for 240 hours. The average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the transparent conductive film treated at 90 ° C. for 240 hours was defined as R ₁ bE, and the two points in the central region of the transparent conductive film. Let R _C bE be the average value of the surface resistance values of , and let R ₂ bE be the average value of the surface resistance values at two points in the second end region located on the opposite side of the first end region.
The value shown by the following formula 1 is the environmental stability evaluation value ES ₆₀ ,
Environmental stability evaluation value ES ₉₀ represented by the following formula 2 [(R ₁ aE/R ₁ S) + (R _C aE/R _C S) + (R ₂ aE/R ₂ S)]/3 ( Formula 1)
[(R ₁ bE/R ₁ S)+(R _C bE/R _C S)+(R ₂ bE/R ₂ S)]/3 (Formula 2)

For example, environmental stability ratings may be measured in the manner shown in FIG. In FIG. 6, two “black circles” indicate two points in the first end region along the longitudinal (MD) direction, and the average value of the surface resistance values of these two points is measured as R ₁ S. be able to.
Similarly, in FIG. 6, "black triangles" indicate two points in the central region of the transparent conductive film, and the average value of the surface resistance values at these two points can be measured as _RCS .
Also, in FIG. 6 , two “black squares” indicate two points in the second end region located on the opposite side of the first end region along the longitudinal (MD) direction, The average value of the surface resistance values at these two points can be measured as R ₂ S.
Each measurement position shown in FIG. 6 is merely an example, and two points in the first end region can be selected within the range assumed by common technical knowledge. Similarly, other measurement positions can be appropriately selected, and evaluation can be performed at positions different from the measurement positions shown in FIG.

The transparent conductive film of the present invention has an environmental stability evaluation value ES ₆₀ represented by Formula 1 of 0.5 or more and 1.5 or less, and an environmental stability evaluation value ES ₉₀ represented by Formula 2 below. Since it is 0.5 or more and 1.5 or less, even in severe environments such as high temperature and high humidity conditions (60 ° C. 95% RH) and high temperature conditions (90 ° C.), the characteristics required for touch panels, such as accurate input characteristics, can be achieved. Satisfied.
In particular, the present invention can exhibit good physical properties under both high temperature and high humidity conditions (60° C. 95% RH) and high temperature conditions (90° C.). Even in a closed space such as the inside of a vehicle when the humidity is high or when the temperature is very high, such as in the summer, the characteristics required of a touch panel, such as accurate input characteristics, can be satisfied. In addition, since the transparent conductive film of the present invention has an environmental stability evaluation value represented by formulas 1 and 2 within the above range, the resistive touch panel can be operated without problems even in the severe environment as described above. possible and preferred.

In one aspect, the Environmental Stability Rating ES ₆₀ for the value represented by Formula 1 is 1.5 or less, may be 1.3 or less, and preferably is 1.2 or less. Also, the environmental stability evaluation value ES ₆₀ represented by Formula 1 is 0.5 or more, may be 0.7 or more, and preferably is 0.8 or more. In one aspect, these upper and lower limits may be combined as appropriate.
Since the environmental stability evaluation value ES ₆₀ is within such a range, the transparent conductive film of the present invention has the properties required as a touch panel even in a severe environment of high temperature and high humidity (60 ° C. 95% RH). , for example, can satisfy accurate input characteristics and durability. Moreover, such a resistive touch panel can be operated without problems, which is preferable.

In one aspect, the Environmental Stability Rating ES ₉₀ for the value represented by Equation 2 is 1.5 or less, may be 1.45 or less, and preferably is 1.4 or less. Also, the environmental stability evaluation value ES ₉₀ represented by Formula 2 is 0.5 or more, may be 0.7 or more, and preferably is 0.8 or more. In one aspect, these upper and lower limits may be combined as appropriate.
Since the environmental stability evaluation value ES ₆₀ is within such a range, the transparent conductive film of the present invention has properties required as a touch panel, such as accurate Input characteristics and durability can be satisfied. Moreover, such a resistive touch panel can be operated without problems, which is preferable.

The transparent conductive film of the transparent conductive film of the present invention is in a semi-crystalline state when the rapid phase change from amorphous to crystalline is halted.
The present inventors succeeded in making the transparent conductive film in a semi-crystalline state and maintaining uniform semi-crystalline properties over the entire surface of the transparent conductive film. As a result, even when exposed to high temperature and high humidity conditions (60° C., 95% RH) for 240 hours, semicrystalline alteration could be suppressed. Furthermore, even when exposed to high temperature conditions (90° C.) for 240 hours, semi-crystalline alteration could be suppressed. As a result, both the environmental stability evaluation value ES ₆₀ and the environmental stability evaluation value ES ₉₀ can be led to 0.5 or more and 1.5 or less, and in addition, the pen sliding durability test and the pen heavy pressure test Also, a remarkable effect can be exhibited.

The transparent conductive film of the transparent conductive film of the present invention is semicrystalline. The semi-crystalline state in the present invention is a state in which the rapid phase change from amorphous to crystalline is stopped in the middle.
The present inventors succeeded in making the transparent conductive film in a semi-crystalline state and maintaining uniform semi-crystalline properties over the entire surface of the transparent conductive film. As a result, by making the transparent conductive film in a semi-crystalline state according to the present invention and making the thickness distribution in the width (TD) direction of the transparent conductive film more uniform, the environmental stability evaluation value ES ₆₀ and the environmental stability It was found that the sex evaluation value ES ₉₀ satisfies the predetermined conditions.

The thickness distribution in the width (TD) direction of the transparent conductive film of the present invention is desirably 5% or less. The thickness distribution in the width (TD) direction of the transparent conductive film can be evaluated by the following method.
(Evaluation of thickness distribution in width (TD) direction of transparent conductive film)
A transparent conductive film roll is cut 50 mm in the longitudinal (MD) direction. The thickness of the cut film is measured every 50 mm in the width (TD) direction from the extreme end of the width (TD) direction, and the thickness is measured to the opposite extreme end. Calculate the thickness distribution.
{(maximum thickness of transparent conductive film) - (minimum thickness of transparent conductive film)}/(maximum thickness of transparent conductive film) x 100 (Formula 3)
In addition, the distance between the opposite end portion and the one point ahead thereof may be less than 50 mm.

When the thickness distribution in the width (TD) direction of the transparent conductive film of the present invention is large, environmental stability evaluation value ES ₆₀ and environmental stability evaluation value ES ₉₀ are likely to change. The reason is described below. In order to produce a transparent conductive film with high productivity, it is preferable to use a roll-to-roll sputtering apparatus. When a film roll (transparent plastic film substrate) with a large thickness distribution in the width (TD) direction is placed in a roll-to-roll type sputtering apparatus, water and organic gas are generated in the width (TD) direction of the film in the film roll. comes out unevenly. That is, when the transparent conductive film is formed on the film, the amount of water and organic gas released from the film differs in the width (TD) direction of the film. In addition, when the amount of water and organic gas is large, defects and hydroxyl groups in the transparent conductive film increase, which may cause a change in semi-crystallinity. As a result, when the thickness distribution in the width (TD) direction is large, the uniformity of the semi-crystallinity of the transparent conductive film in the semi-crystalline state is lost in the width (TD) direction of the film. The ES ₆₀ and ES ₉₀ Environmental Stability Ratings are considered to be variable.
However, simply having the thickness distribution in the width (TD) direction of the transparent conductive film within a predetermined range does not provide the effects of the present invention. That is, in the present invention, the evaluation results of the pen sliding durability test, the evaluation results of the pen heavy pressure durability test, and the evaluation results of the environmental stability test are also included within the scope of the present invention, so that various effect can be exhibited more highly.

If the thickness distribution in the width (TD) direction of the transparent conductive film of the present invention is 5% or less, the film in the film roll in the width (TD) direction is water and/or organic gases are uniformly released from the film roll. As a result, semi-crystallinity becomes more uniform, defects and hydroxyl groups are reduced, and the environmental stability evaluation value ES ₆₀ and the environmental stability evaluation value ES ₉₀ satisfy predetermined conditions, which is desirable.
For example, the thickness distribution in the width (TD) direction of the transparent conductive film may be 4.8% or less, preferably 4.5% or less.
The thickness distribution in the width (TD) direction of the transparent conductive film is preferably as small as possible. In one aspect, these upper and lower limits may be combined as appropriate.

The production method for obtaining the transparent conductive film of the present invention is not particularly limited, but for example, the following production methods can be preferably exemplified.
A 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 that feeds a film roll and winds up the film in the form of a film roll after film formation. Hydrogen atom-containing gas (hydrogen, ammonia, mixed gas of hydrogen + argon, etc., is not particularly limited as long as it contains hydrogen atoms. However, water is excluded.) In addition, the film temperature during sputtering is set to 0 ° C. or less, and a sintered target of indium-tin composite oxide containing 0.5 to 10% by mass of tin oxide is used, and an indium-tin composite oxide is used. The thickness of the transparent conductive film is adjusted to 10 to 30 nm, and the three-dimensional surface roughness SRa of the transparent conductive film of indium-tin composite oxide is 1 to 100 nm. Film formation can be preferably employed. In the film formation atmosphere during sputtering, the hydrogen atom-containing gas has the effect of inhibiting crystallization of the transparent conductive film. When hydrogen gas is flowed in the film formation atmosphere, the value of (hydrogen gas flow rate) ÷ (inert gas flow rate + hydrogen gas flow rate) × 100 (sometimes simply referred to as hydrogen concentration) is 0.01 to 3. .00% is desirable. 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.
A hydrogen concentration within such a range can contribute to good results in both the ON resistance value of the pen sliding durability test and the pen heavy pressure durability test, for example.

Inert gases include helium, neon, argon, krypton, and xenon. A hydrogen concentration of 0.01 to 3.00% is preferable because the transparent conductive film can be made semicrystalline. When using a hydrogen atom-containing gas other than hydrogen gas, the amount of hydrogen atoms contained in the hydrogen atom-containing gas may be converted into the amount of hydrogen gas (=hydrogen molecules) for calculation. The gas outlet is arranged so that the hydrogen atom-containing gas can be uniformly blown in the direction perpendicular to the longitudinal direction of the film roll when precisely flowing the hydrogen atom-containing gas into the film formation atmosphere with a mass flow controller. By doing so, it is difficult to obtain a transparent conductive film in which portions with high crystallinity and portions with low crystallinity are mixed, and it is easy to obtain a uniform semi-crystalline transparent conductive film, so excellent pen sliding durability and pen heavy pressure It becomes 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.

If the water and organic gas generated from the film are generated unevenly from the inside of the film, the semi-crystallinity of the transparent conductive film becomes uneven, and defects and hydroxyl groups increase, resulting in an environmental stability evaluation value. ES ₆₀ and Environmental Stability Rating ES ₉₀ tend to be variable. As a countermeasure by the manufacturing method, it is desirable to continuously form at least two layers of transparent conductive films on a film roll.
In one embodiment, the transparent conductive film precursor is deposited until the thickness of the transparent conductive film precursor reaches 35 to 65% of the total thickness of the transparent conductive film. In the present invention, the transparent conductive film precursor obtained under such conditions is referred to as a seed layer.
Furthermore, when using a hydrogen atom-containing gas when forming the seed layer, the median value of the ratio of the water pressure to the inert gas in the film formation atmosphere during sputtering on the film roll (water pressure / inert gas partial pressure) It is desirable to control X, that is, the intermediate value between the maximum and minimum values of the above ratio to be 1.00×10 ⁻³ to 4.80×10 ⁻³ .
The precursor of the transparent conductive film is formed until the thickness of the precursor of the transparent conductive film reaches 35 to 65% of the total thickness of the transparent conductive film, that is, the seed layer is formed to form the base film. Since a transparent conductive film is formed on the film, the generation of water and organic gas from the film can be sufficiently suppressed, and the non-uniformity of the amount of water and/or organic gas generated from various parts of the film surface can be sufficiently reduced. can.
In the case of using a hydrogen atom-containing gas, by controlling X to 1.00×10 ⁻³ to 4.80×10 ⁻³ , a semi-crystalline film with high uniformity in the plane of the film of the present invention can be obtained. It becomes a seed layer for growing a transparent conductive film. The seed layer may be one layer or two layers or more.

Although it should not be interpreted as being limited to a specific theory, in the present invention, the decrease in crystallinity of the transparent conductive film that can occur when there is a large amount of water and organic gas generated from the film is suppressed, and the desired state is achieved. can maintain semi-crystallinity. As a result, it is possible to suppress the increase of defective parts of the transparent conductive film, hydroxyl groups, etc., which cause deterioration under high temperature, high humidity, and high temperature, and the environmental stability evaluation value ES ₆₀ and the environmental stability evaluation value ES ₉₀ can be suppressed. is presumed to satisfy the conditions of

In the present invention, for example, it is desirable to continuously form at least two or more transparent conductive films on a film roll as a countermeasure by the manufacturing method. When forming a transparent conductive film until the thickness of the transparent conductive film reaches 35 to 65% of the total thickness of the transparent conductive film, and when using a hydrogen atom-containing gas, film formation during sputtering on a film roll. It is desirable to control the median value X (value between the maximum value and the minimum value) of the ratio of water pressure to inert gas in the atmosphere to be 1.00×10 ⁻³ to 4.80×10 ⁻³ . By forming a transparent conductive film (seed layer) until the thickness of the transparent conductive film reaches 35 to 65% of the total thickness of the transparent conductive film, the transparent conductive film is formed on the film, so The generation of water and organic gas can be sufficiently suppressed. As a result, it is possible to sufficiently reduce the increase in defects, hydroxyl groups, and the like in the transparent conductive film, which cause deterioration under high temperature, high humidity, and high temperature. In the case of using a hydrogen atom-containing gas, by controlling X to 1.00×10 ⁻³ to 4.80×10 ⁻³ , a semicrystalline transparent conductive film with few defects and hydroxyl groups can be obtained. becomes a seed layer for growing The seed layer may be one layer or two layers or more. Next, when forming a transparent conductive film on the seed layer until the thickness of the transparent conductive film reaches the target total thickness of the transparent conductive film, furthermore, when using a hydrogen atom-containing gas, the seed layer The central value Y of the ratio of the water pressure to the inert gas in the film forming atmosphere during sputtering (water pressure/inert gas partial pressure), that is, the intermediate value between the maximum value and the minimum value of the above ratio, is 0.15 × It is desirable to control from 10 ⁻³ to 0.90×10 ⁻³ .

Furthermore, it is desirable to control the average Z of X and Y to 0.58×10 ⁻³ to 2.80×10 ⁻³ . One transparent conductive film or two or more transparent conductive films may be formed on the seed layer. As a result, a semi-crystalline transparent conductive film with few defects and hydroxyl groups can be produced, and it is assumed that the environmental stability evaluation value ES ₆₀ and the environmental stability evaluation value ES ₉₀ can satisfy the predetermined conditions according to the present invention. be done.
Furthermore, regarding Z, when the difference between the maximum value and the minimum value from the start of film formation to the end of film formation was 1.00×10 ⁻³ or less, the uniformity of the crystallinity of the transparent conductive film was maintained over the entire length of the film. be For example, in addition to rotary pumps, turbomolecular pumps, and cryopumps that are often used as exhaust devices for sputtering machines, the following bombardment process, limiting the height difference of unevenness on the end surface of the film roll described below, and forming a transparent conductive film When forming a transparent conductive film, the amount of water released from the film can be reduced by applying a protective film with a low water absorption rate to the opposite side of the film, and the amount of water released can be uniform over the entire length of the film. This is preferable because it eliminates the need for precise control of the amount. However, Z also depends somewhat on the content of tin oxide in the transparent conductive film of the indium-tin composite oxide, the thickness of the transparent conductive film, and the like. When the amount of tin oxide added to the transparent conductive film of the indium-tin composite oxide is large, or when the transparent conductive film is thin, it is desirable to set Z to a lower value within the above range. Conversely, when the content of tin oxide in the transparent conductive film of the indium-tin composite oxide is small, when the transparent conductive film is thick, etc., Z, which is the central value of the ratio of the water pressure to the inert gas, is set to It is desirable to set it higher in the range.

It is preferable to form the transparent conductive film on the transparent plastic film by setting the film temperature to 0° C. or lower during sputtering. The film temperature during film formation is substituted by the set temperature of a temperature controller that adjusts the temperature of the center roll with which the running film is in contact.
Here, FIG. 5 shows a schematic diagram of an example of a sputtering apparatus preferably used in the present invention. An indium-tin sputtering target 4 is placed through a chimney 3 , and a thin film of indium-tin composite oxide is deposited and laminated on the surface of the film 1 running on the center roll 2 . Each target is separated by a partition 5 . The temperature of the center roll 2 is controlled by a temperature controller (not shown). If the film temperature is 0°C or less, it is possible to suppress the release of impurity gases such as water and organic gases from the film, which cause variations in the crystallinity of the transparent conductive film. This is preferable because the crystallinity of the conductive film is easily made uniform. When using a hydrogen atom-containing gas, the average Z of X and Y is preferably 0.58×10 ⁻³ to 2.80×10 ⁻³ . It is desirable that Z is within the above range because the hydrogen atom-containing gas effectively inhibits the crystallinity of the transparent conductive film. In addition, in order to bring the surface resistance and total light transmittance of the transparent conductive film to a practical level, it is desirable to add oxygen gas during sputtering. This manufacturing method aims at controlling the crystallinity with a hydrogen-containing gas while eliminating as much as possible the effect of water on the crystallinity, which is a factor that causes variation in the crystallinity of the transparent conductive film.

In order to control the water content when forming an indium-tin composite oxide film on a plastic film, it is better to actually observe the water content during film formation than to observe the ultimate vacuum. desirable for two reasons.

The first reason is that when a film is formed on a plastic film by sputtering, the film is heated and moisture is released from the film, so the amount of moisture in the film-forming atmosphere increases, and the ultimate vacuum was measured. It is more accurate to express the moisture content at the time of film formation rather than the ultimate degree of vacuum, since the moisture content increases more than the moisture content at the time of film formation.

The second reason for this is the case of an apparatus into which a large amount of transparent plastic film is fed. In such devices the film is input in the form of film rolls. When the film is rolled and placed in a vacuum chamber, the outer layer of the roll is easy to drain, but the inner layer of the roll is difficult to drain. When the ultimate vacuum is measured, the film roll is stopped, but since the film roll is running during film formation, the inner layer part of the film roll containing a lot of water is unwound, so the moisture in the film formation atmosphere This is because the amount of water increases, and the amount of water increases more than the amount of water when the degree of ultimate vacuum is measured. In the present invention, the control of the water content in the film-forming atmosphere can be preferably handled by observing the ratio of the water pressure to the inert gas in the film-forming atmosphere during sputtering.

Prior to depositing the transparent conductive film, it is desirable to pass the film through a bombardment process. The bombardment process is to generate plasma by applying a voltage to generate a discharge while only an inert gas such as argon gas or a mixed gas of a reactive gas such as oxygen and an inert gas is 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 in the bombardment process, water and organic components are released from the film. It is preferable because the crystallinity of the transparent conductive film can be easily made uniform until the end, the defect portions of the transparent conductive film of the transparent conductive film can be reduced, and moreover, hydroxyl groups and the like can be reduced. In addition, since the layer in contact with the transparent conductive film is activated by the bombardment 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.

A film roll for forming a transparent conductive film preferably has a height difference of 10 mm or less between the most convex part and the most concave part on the end surface of the roll. If the thickness is 10 mm or less, the unevenness in the way water and organic components are released from the film end surface when the film roll is put into the sputtering device becomes small, so the crystal of the transparent conductive film from the start of film formation to the end of film formation. It is preferable because the properties can be easily made uniform, the number of defects in the transparent conductive film of the transparent conductive film can be reduced, and moreover, hydroxyl groups and the like can be reduced.

In the film (transparent plastic film substrate) on which the transparent conductive film is to be formed, it is desirable to attach a protective film having a low water absorption rate to the surface opposite to the surface on which the transparent conductive film is to be formed. By applying a protective film with a low water absorption rate, it becomes difficult for gases such as water to be released from the film base material, and as a result, the unevenness in the way gases such as water are released is reduced, so the film starts to grow from the start of film formation. It is preferable because the crystallinity of the transparent conductive film is easily uniformed until the film is finished, and the crystallinity in the plane of the transparent conductive film of the transparent conductive film is easily uniformized. Polyethylene, polypropylene, cycloolefin and the like are preferable as the base material of the protective film having a low water absorption rate.

In the method of forming a transparent conductive film of crystalline indium-tin composite oxide on at least one surface of a transparent plastic film substrate, it is desirable to introduce oxygen gas during sputtering. When oxygen gas is introduced during sputtering, problems due to lack of oxygen in the transparent conductive film of the indium-tin composite oxide do not occur, and the transparent conductive film has a low surface resistance and a high total light transmittance, which is preferable. Therefore, in order to bring the surface resistance and total light transmittance of the transparent conductive film to a practical level, it is desirable to introduce oxygen gas during sputtering. The total light transmittance of the transparent conductive film of the invention is preferably 70 to 95%.

The transparent conductive film of the present invention is produced by laminating a transparent conductive film of an indium-tin composite oxide on a transparent plastic film substrate, and then heating it at 80 to 200° C. at 0.1 to 0.1 in an oxygen-containing atmosphere. It is desirable to be heat-treated for 12 hours. When the temperature is 80° C. or higher, it is easy to slightly increase the crystallinity so as to obtain a 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 secured, which is preferable.

<Transparent plastic film substrate>
The transparent plastic film substrate used in the present invention is a film obtained by melt-extrusion or solution-extrusion of an organic polymer into a film, and if necessary, stretching in the longitudinal direction and/or the width direction, cooling, and heat setting. and 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, polyether Sulfan, polyether ether ketone, polycarbonate, polyarylate, cellulose propionate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyetherimide, polyphenylene sulfide, polyphenylene oxide, polystyrene, syndiotactic polystyrene, norbornene polymer, etc. is 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 monomers of other organic polymers, or may be blended with other organic polymers.

The transparent plastic film substrate used in the present invention may be subjected to surface activation treatment such as corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, ozone treatment, etc., within the scope not impairing the object of the invention. It may be subjected to a hardening treatment.

When a curable resin layer is applied to a transparent plastic film substrate, 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., of the film are suppressed, and cracking, peeling, etc., of the transparent conductive film in a pen heavy pressure test are suppressed. In addition, if the transparent conductive film is formed on the surface of the curable resin layer with unevenness, the true contact area when the transparent conductive film comes into contact with the glass during the pen sliding test decreases. It can be expected that the slipperiness between the transparent conductive film and the transparent conductive film will be improved, 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 expected. , the amount of deformation of the surface projections becomes large when a pen heavy pressure test is performed, and cracks occur in the transparent conductive film, which is not preferable. Therefore, it is preferable that the three-dimensional surface roughness SRa of the transparent conductive film is 1 to 100 nm as the surface unevenness. Details of the curable resin layer are described below.

In addition, the curable resin preferably used in the present invention is not particularly limited as long as it is a resin that is cured by applying energy such as heating, ultraviolet irradiation, electron beam irradiation, etc. Silicone resins, acrylic resins, methacrylic resins, epoxy resins. , 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 UV-curable resins include, for example, polyfunctional acrylate resins such as acrylic or methacrylic acid esters of polyhydric alcohols, diisocyanates, polyhydric alcohols, and hydroxyalkyl esters of acrylic acid or methacrylic acid. Polyfunctional urethane acrylate resins such as those described above can be mentioned. If necessary, a monofunctional monomer such as vinylpyrrolidone, methyl methacrylate, or styrene can be added to these polyfunctional resins for copolymerization.

Moreover, in order to improve the adhesion 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 glow or corona discharge is applied to increase carbonyl groups, carboxyl groups, and hydroxyl groups, and an acid or alkali treatment method to increase polar groups such as amino groups, hydroxyl groups, and carbonyl groups. A chemical treatment method, etc., to be treated can be mentioned.

UV-curable resins are usually used by adding a photopolymerization initiator. As the photopolymerization initiator, any known compound that absorbs ultraviolet rays and generates radicals can be used without particular limitation. etc. can be mentioned. The amount of the photopolymerization initiator to be added is preferably 1 to 5 parts by mass per 100 parts by mass of the ultraviolet curable resin.

In the present invention, the curable resin layer preferably contains inorganic particles and organic particles in addition to the curable resin, which is the main component. By dispersing inorganic particles or organic particles in the curable resin, unevenness is formed on the surface of the curable resin, and surface roughness in a wide area can be improved.

Silica etc. are illustrated as said inorganic particle. Examples of the organic particles include polyester resins, polyolefin resins, polystyrene resins, polyamide resins, and the like.

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

Examples of non-compatible resins include polyester resins, polyolefin resins, polystyrene resins, polyamide resins, and the like.

Here, as an example, the mixing ratio when inorganic particles are used in the curable resin layer 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 protrusions formed on the surface of the curable resin layer are not too small, and the three-dimensional surface roughness can be effectively imparted. When subjected to a pen heavy pressure test, the amount of deformation of the surface projections is reduced, the occurrence of cracks in the transparent conductive film is suppressed, and the transparent conductive film has some surface projections, which is preferable because film windability can be maintained.

The UV-curable resin, the photopolymerization initiator, and the resin incompatible with the inorganic particles, organic particles, and UV-curable resin are dissolved in a common solvent to prepare a coating liquid. The solvent to be used is not particularly limited, and examples thereof include alcohol solvents such as ethyl alcohol and isopropyl alcohol, ester solvents such as ethyl acetate and butyl acetate, and dibutyl ether and ethylene glycol monoethyl ether. Ether-based solvents, ketone-based solvents such as methyl isobutyl ketone and cyclohexanone, and aromatic hydrocarbon-based solvents such as toluene, xylene, solvent naphtha, and the like can be used singly or in combination. The higher the amount of the ultraviolet curable resin, the photopolymerization initiator, and the solvent that dissolves in the resin incompatible with the inorganic particles, organic particles, and ultraviolet curable resin, that is, the lower the solid content concentration. is preferable because the thickness distribution of the curable resin layer is small.

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 UV-curable resin, the photopolymerization initiator and the high-molecular-weight polyester resin in the coating liquid is usually 20 to 80% by mass. If necessary, other known additives such as a silicone leveling agent may be added to the coating liquid.

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 bar coating, gravure coating and reverse coating can be used.

In the coating liquid coated, the solvent is removed by evaporation in the next drying step. In this step, the high-molecular-weight polyester resin uniformly dissolved in the coating solution is precipitated in the UV-curable resin as particles. After drying the coating film, 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 particles of the high-molecular-weight polyester resin are fixed in the hard coat layer and form projections on the surface of the curable resin layer to improve surface roughness over a wide area.

Moreover, 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, 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 projections are formed, which is preferable. On the other hand, if the thickness is 15 μm or less, the productivity is good and it is preferable. Moreover, the thickness distribution of the curable resin layer is preferably 5% or less.

EXAMPLES 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 measurement evaluations in the examples were performed by the following methods.

(1) Total light transmittance Based on JIS-K7361-1:1997, the total light transmittance was measured using NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd.

(2) Surface resistance value Measured by the four-probe method in accordance with JIS-K7194:1994. Lotesta AX MCP-T370 manufactured by Mitsubishi Chemical Analytech Co., Ltd. was used as the measuring instrument.

(3) Three-dimensional center plane average surface roughness SRa
The three-dimensional center plane average surface roughness SRa is defined in ISO 25178, and is a three-dimensional surface profile measuring device Vertscan (manufactured by Ryoka Systems Co., Ltd., R5500H-M100 (measurement conditions: wave mode, measurement wavelength 560 nm, A three-dimensional center plane average surface roughness SRa was obtained using a 10x objective lens)). The number of measurements was set to 5, and their average value was obtained. Here, the first decimal place in nm units was rounded off.

(4) Crystal grain size A film sample piece laminated with a transparent conductive thin film layer was cut into a size of 1 mm x 10 mm, and was attached to the upper surface of a suitable resin block with the conductive thin film surface facing outward. After trimming it, an ultrathin section almost parallel to the film surface was made by a common ultramicrotome technique.
This section was observed with a transmission electron microscope (JEM-2010, manufactured by JEOL), and the conductive thin film surface portion without significant damage was selected and photographed at an acceleration voltage of 200 kV and a direct magnification of 40,000.
In crystal grains observed under a transmission electron microscope, the longest part of all crystal grains is measured, and the average value of the measured values is taken as the crystal grain size. Here, FIGS. 1 to 4 show an example of a method for recognizing the longest part of a crystal grain when measuring the longest part. That is, the longest portion is determined by the length of the straight line that allows the largest measurement of the grain size of each crystal grain.

(5) Thickness of transparent conductive film (film thickness)
A film sample piece laminated with a transparent conductive thin film layer was cut into a size of 1 mm×10 mm and embedded in an epoxy resin for electron microscopes. This was fixed to a sample holder of an ultramicrotome, and a cross-sectional slice parallel to the short side of the embedded sample piece was produced. Then, a transmission electron microscope (manufactured by JEOL, JEM-2010) is used to photograph a portion of the section where the thin film is not significantly damaged at an acceleration voltage of 200 kV and a bright field with an observation magnification of 10,000 times. The film thickness was obtained from the obtained photograph.

(6) Pen sliding durability test Using the transparent conductive film according to the present invention as one panel plate, as the other panel plate, an indium-tin composite oxide thin film having a thickness of 20 nm by sputtering on a glass substrate ( Tin oxide content: 10% by mass) was used. A touch panel was produced by arranging these two panel plates so that the transparent conductive thin films faced each other with epoxy beads having a diameter of 30 μm interposed therebetween. Next, a linear sliding test of 180,000 reciprocations was performed on the touch panel by applying a load of 2.5 N to a pen made of polyacetal (tip shape: 0.8 mmR). In this test, a pen load is applied to the surface of the transparent conductive film according to the present invention. The sliding distance at this time was 30 mm, and the sliding speed was 180 mm/sec. After this sliding durability test, the ON resistance (the resistance value when the movable electrode (film electrode) and the fixed electrode are in contact) was measured when the sliding portion was pressed with a pen load of 0.8N. It is desirable that the ON resistance is 10 kΩ or less.
In addition, in the comparative examples, the film in each comparative example was used instead of the transparent conductive film according to the present invention.

(7) 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 was used as one panel plate, and as the other panel plate, the thickness was increased by sputtering on a glass substrate. A transparent conductive thin film made of a 20 nm indium-tin composite oxide thin film (tin oxide content: 10% by mass) was used. These two panel plates are arranged so that the transparent conductive thin films face each other, with epoxy beads having a diameter of 30 μm interposed therebetween. A touch panel was produced by pasting the plates. A polyacetal pen (tip shape: 0.8 mmR) is applied at a position 2.0 mm from the end of the double-sided tape with a load of 35 N, and the double-sided tape is linearly slid 10 times (5 times reciprocating) parallel to the double-sided tape. In this test, a pen load is applied to the surface of the transparent conductive film according to the present invention. The sliding distance at this time is 30 mm, and the sliding speed is 20 mm/sec. However, the sliding is performed at the position where there is no epoxy bead. After sliding, remove the transparent conductive film, measure the surface resistance (four-probe method) at any five locations on the sliding portion, and calculate the average value. When measuring the surface resistance, align the four terminals in a direction perpendicular to the sliding part so that the sliding part is between the second and third terminals. The increase rate of the surface resistance is calculated by dividing the average value of the surface resistance of the sliding portion by the surface resistance of the non-sliding portion (measured by the 4-probe method).
In addition, in the comparative examples, the film in each comparative example was used instead of the transparent conductive film according to the present invention.

(8) Measurement of Tin Oxide Content in Transparent Conductive Film Cut a sample (approximately 15 cm ² ) and put it in a quartz Erlenmeyer flask, add 20 ml of 6 mol/l hydrochloric acid, and seal with a film to prevent volatilization of the acid. Did. The transparent conductive film was dissolved by allowing it to stand at room temperature for 9 days with occasional shaking. 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 the calibration curve method using an ICP emission spectrometer (manufacturer: Rigaku, device model: CIROS-120 EOP). As the measurement wavelength for each element, a wavelength with no interference and high sensitivity was selected. In addition, standard solutions of commercially available In and Sn were diluted and used.

(9) Adhesion test It was carried out in accordance with JIS K5600-5-6:1999.

(10) Bending resistance test It was carried out according to JIS K5600-5-1:1999. However, when cracking and peeling did not occur up to a mandrel diameter of 13 mm, no further bending endurance test was performed, and all were described as 13 mm.

(11) Evaluation of Environmental Stability A transparent conductive film roll was cut to 100 mm in the longitudinal (MD) direction. The cut film was heat-treated at 165° C. for 75 minutes.
Let R ₁ S be the average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the heat-treated transparent conductive film, and the surface resistance at two points in the central region of the transparent conductive film. Let R _C S be the average value of the values, and let R ₂ S be the average value of the surface resistance values at two points in the second end region located on the opposite side of the first end region.
Next, the heat-treated transparent conductive film was further treated under high-temperature and high-humidity conditions at 60° C. and 95% RH for 240 hours. The average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the transparent conductive film treated at 60 ° C. 95% RH for 240 hours is defined as R ₁ aE, and in the central region of the transparent conductive film The average value of the surface resistance values at the two points is R _C aE, and the average value of the surface resistance values at the two points in the second end region located on the opposite side of the first end region is R ₂ aE. do.
Moreover, the transparent conductive film heat-treated at 165° C. for 75 minutes was further treated at 90° C. for 240 hours. The average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the transparent conductive film treated at 90 ° C. for 240 hours was defined as R ₁ bE, and the two points in the central region of the transparent conductive film. Let R _C bE be the average value of the surface resistance values of , and let R ₂ bE be the average value of the surface resistance values at two points in the second end region located on the opposite side of the first end region.
The value shown by the following formula 1 is the environmental stability evaluation value ES ₆₀ ,
Each value was calculated using the environmental stability evaluation value ES ₉₀ shown in the following formula 2.
[(R ₁ aE/R ₁ S)+(R _C aE/R _C S)+(R ₂ aE/R ₂ S)]/3 (Formula 1)
[(R ₁ bE/R ₁ S)+(R _C bE/R _C S)+(R ₂ bE/R ₂ S)]/3 (Formula 2)
In addition, environmental stability evaluation was measured in the mode shown in FIG. In FIG. 6, the two "filled circles" indicate two points in the first end region along the longitudinal (MD) direction, and the "filled triangles" indicate two points in the central region of the transparent conductive film. , “filled squares” indicate two points in the second end region located opposite the first end region along the longitudinal (MD) direction.

(12) Thickness distribution evaluation in the width (TD) direction of the transparent conductive film)
A transparent conductive film roll was cut to 50 mm in the longitudinal (MD) direction. The thickness of the cut film is measured every 50 mm in the width (TD) direction from the extreme end of the width (TD) direction, and the thickness is measured to the opposite extreme end. Thickness distribution was calculated. However, in some cases, the distance between the opposite end and the one point before it was less than 50 mm.
The thickness of the transparent conductive film was measured with a micrometer.
[(maximum thickness of transparent conductive film) - (minimum thickness of transparent conductive film)]/(maximum thickness of transparent conductive film) x 100 (Formula 3)

The transparent plastic film base material used in Examples and Comparative Examples is a biaxially oriented transparent PET film (A4340, manufactured by Toyobo Co., Ltd., thickness is shown in Table 1) having easy-adhesion layers on both sides. As a curable resin layer, silica particles (manufactured by Nissan Chemical Co., Ltd., Snowtex ZL) are added to 100 parts by mass of an acrylic resin containing a photopolymerization initiator (manufactured by Dainichiseika Kogyo Co., Ltd., Seika Beam (registered trademark) EXF-01J). 1 is blended, and a mixed solvent of toluene/MEK (8/2: mass ratio) is added as a solvent so that the solid content concentration is as shown in Tables 1 and 2, and stirred to dissolve uniformly. Then, a coating liquid was 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 average value of the thickness of the coating film at arbitrary five points was 5 μm. After drying at 80° C. for 1 minute, the coating film was cured by irradiating ultraviolet rays (light amount: 300 mJ/cm ² ) using an ultraviolet irradiation device (manufactured by Eye Graphics, UB042-5AM-W type). . Moreover, the curable resin layer was provided on both sides of the transparent plastic substrate.

(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 oxygen was introduced, argon as an inert gas and hydrogen gas as a hydrogen-containing gas were introduced at concentrations shown in Table 1 to make the total pressure 0.6 Pa.
An indium-tin composite oxide sintered target or an indium oxide sintered target containing no tin oxide is supplied with power at a power density of 4.5 W/cm ² , and a seed layer and then a transparent layer are formed by DC magnetron sputtering. A conductive film was formed. The film thickness was controlled by changing the speed at which the film passed over the target. Also, 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). In order to adjust the water pressure ratios X, Y, and the average Z of X and Y in the deposition atmosphere during sputtering, for each example level, the bombardment process was carried out as described in Table 1. The presence or absence of a protective film, the unevenness of the film roll end face, and the temperature of the heating medium of the temperature controller that controls the temperature of the center roll on which the film is running in contact were adjusted. Table 1 shows the center value of the temperature that is right in the middle between the maximum and minimum temperatures from the start of film formation on the film roll to the end of film formation.
The film formed by laminating the transparent conductive film was subjected to the heat treatment described in Table 1A, and then measured. The measurement results are shown in Table 1B.

(Comparative Examples 1 to 11)
A transparent conductive film was produced and evaluated in the same manner as in Example 1 under the conditions shown in Table 1. However, in Comparative Example 7, no curable resin layer was provided. However, in Comparative Example 8, the coating film thickness of the curable resin layer was adjusted to 20 μm. The film formation conditions are shown in Table 2A, and the results are shown in Table 2B.

As shown in Table 1B, the transparent conductive films of Examples 1 to 8 are excellent in pen sliding durability and pen heavy pressure durability, and have both properties. Furthermore, it is excellent in both high-temperature and high-humidity conditions and high-temperature conditions, and has excellent environmental stability.
However, as shown in Table 2B, Comparative Examples 1 to 11 cannot achieve both pen sliding durability and pen heavy pressure durability. Furthermore, they could not have good environmental stability.

As described above, according to the present invention, a transparent conductive film having excellent pen sliding durability, pen heavy pressure durability, and environmental stability can be produced, which is extremely useful for applications such as resistive touch panels. be.

1. film 2 . Center roll 3 . Chimney 4. Indium-tin composite oxide target5. Chamber

Claims (6)

A 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, and has a total light transmittance of 70 to 95%, and the following pen rubbing The ON resistance of the transparent conductive film of the transparent conductive film in a dynamic durability test is 10 kΩ or less,
The increase rate of the surface resistance value of the transparent conductive film of the transparent conductive film in the following pen heavy pressure test is 1.5 or less,
The environmental stability evaluation value ES ₆₀ represented by the following formula 1 is 0.5 or more and 1.5 or less, and
Environmental stability evaluation value ES ₉₀ represented by the following formula 2 is 0.5 or more and 1.5 or less,
Transparent conductive film.
(Pen sliding durability test method)
Using the transparent conductive film according to the present invention as one panel plate, and as the other panel plate, an indium-tin composite oxide thin film having a thickness of 20 nm (tin oxide content: 10% by mass) was formed on a glass substrate by a sputtering method. A transparent conductive thin film consisting of The two panel plates are arranged so that the transparent conductive thin films face each other with epoxy beads having a diameter of 30 μm interposed therebetween, and the panel plate on the film side and the panel plate on the glass side are attached with double-sided tape having a thickness of 170 μm. , to produce a touch panel. Next, a linear sliding test of 180,000 reciprocations is performed on the touch panel by applying a load of 2.5 N to a pen made of polyacetal (tip shape: 0.8 mmR). In this test, a pen load is applied to the surface of the transparent conductive film according to the present invention.
The sliding distance at this time 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 are in contact) is measured when the sliding portion is pressed with a pen load of 0.8N.
(Pen heavy pressure test method)
A transparent conductive film according to the present invention cut to 50 mm × 50 mm was used as one panel plate, and as the other panel plate, an indium-tin composite oxide thin film (tin oxide content: 10% by mass). These two panel plates are arranged so that the transparent conductive thin films face each other, with epoxy beads having a diameter of 30 μm interposed therebetween. A touch panel was produced by pasting the plates. A polyacetal pen (tip shape 0.8 mmR) is applied at a position 2.0 mm from the end of the double-sided tape with a load of 35 N, and the double-sided tape is linearly slid 10 times (5 times reciprocating) parallel to the double-sided tape. In this test, a pen load is applied to the surface of the transparent conductive film according to the present invention. The sliding distance at this time is 30 mm, and the sliding speed is 20 mm/sec. Sliding is performed at the position where there is no epoxy bead. After sliding, remove the transparent conductive film, measure the surface resistance (four-probe method) at any five locations on the sliding portion, and calculate the average value. When measuring the surface resistance, align the four terminals in a direction perpendicular to the sliding part so that the sliding part is between the second and third terminals. The increase rate of the surface resistance is calculated by dividing the average value of the surface resistance of the sliding portion by the surface resistance of the non-sliding portion (measured by the 4-probe method).
(Environmental stability evaluation)
A transparent conductive film roll is cut to 100 mm in the longitudinal (MD) direction. The cut film is heat-treated at 165° C. for 75 minutes.
Let R ₁ S be the average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the heat-treated transparent conductive film, and the surface resistance at two points in the central region of the transparent conductive film. Let R _C S be the average value of the values, and let R ₂ S be the average value of the surface resistance values at two points in the second end region located on the opposite side of the first end region.
Next, the heat-treated transparent conductive film is further treated at 60° C. and 95% RH for 240 hours under high temperature and high humidity conditions. The average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the transparent conductive film treated at 60 ° C. 95% RH for 240 hours is defined as R ₁ aE, and in the central region of the transparent conductive film The average value of the surface resistance values at the two points is R _C aE, and the average value of the surface resistance values at the two points in the second end region located on the opposite side of the first end region is R ₂ aE. do.
Moreover, the transparent conductive film heat-treated at 165° C. for 75 minutes is further treated at 90° C. for 240 hours. The average value of the surface resistance values at two points in the first end region along the longitudinal (MD) direction of the transparent conductive film treated at 90 ° C. for 240 hours was defined as R ₁ bE, and the two points in the central region of the transparent conductive film. Let R _C bE be the average value of the surface resistance values of , and let R ₂ bE be the average value of the surface resistance values at two points in the second end region located on the opposite side of the first end region.
The value shown by the following formula 1 is the environmental stability evaluation value ES ₆₀ ,
Environmental stability evaluation value ES ₉₀ represented by the following formula 2 [(R ₁ aE/R ₁ S) + (R _C aE/R _C S) + (R ₂ aE/R ₂ S)]/3 ( Formula 1)
[(R ₁ bE/R ₁ S)+(R _C bE/R _C S)+(R ₂ bE/R ₂ S)]/3 (Formula 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 indium-tin composite oxide The transparent conductive film according to claim 1, wherein the transparent conductive film contains 0.5 to 10% by mass of tin oxide. The transparent conductive film of indium-tin composite oxide has a thickness of 10 to 30 nm, and the transparent conductive film of indium-tin composite oxide has a three-dimensional surface roughness SRa of 1 to 100 nm. 3. The transparent conductive film according to claim 1, wherein the thickness distribution in the width (TD) direction is 5% or less.
(Evaluation of thickness distribution in width (TD) direction of transparent conductive film)
A transparent conductive film roll is cut 50 mm in the longitudinal (MD) direction. The thickness of the cut film is measured every 50 mm in the width (TD) direction from the extreme end of the width (TD) direction, and the thickness is measured to the opposite extreme end. Calculate the thickness distribution.
Also, the distance between the opposite end portion and the measurement site one point before it may be less than 50 mm.
[(maximum thickness of transparent conductive film) - (minimum thickness of transparent conductive film)]/(maximum thickness of transparent conductive film) x 100 (Formula 3) The transparent conductive film does not peel off even when an adhesion test (JIS K5600-5-6: 1999) is performed on the surface of the transparent conductive film,
A flex resistance test (JIS K5600-5-1: 1999) was performed on the transparent conductive film side of the indium-tin composite oxide of the transparent conductive film, and when the flexed portion was observed with a magnifying glass of 10x magnification, no cracks or peeling occurred. 4. A transparent conductive film according to any one of claims 1 to 3, wherein the resulting mandrel diameter is less than 20 mm. The transparent conductive film according to any one of claims 1 to 4, wherein the transparent conductive film has a thickness of 100 to 250 µm. 6. The transparent conductive film according to claim 1, further comprising a curable resin layer between the transparent conductive film of indium-tin composite oxide and the transparent plastic film substrate.

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