CN115769315A - Transparent conductive film - Google Patents
Transparent conductive film Download PDFInfo
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- CN115769315A CN115769315A CN202180044765.3A CN202180044765A CN115769315A CN 115769315 A CN115769315 A CN 115769315A CN 202180044765 A CN202180044765 A CN 202180044765A CN 115769315 A CN115769315 A CN 115769315A
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- transparent conductive
- conductive film
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/02—Physical, chemical or physicochemical properties
- B32B7/025—Electric or magnetic properties
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/045—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B5/00—Non-insulated conductors or conductive bodies characterised by their form
- H01B5/14—Non-insulated conductors or conductive bodies characterised by their form comprising conductive layers or films on insulating-supports
Abstract
The invention provides a transparent conductive film which has excellent pen sliding durability, pen heavy pressure durability and high fineness when used in a touch panel. A transparent conductive film comprising a transparent plastic film substrate and a transparent conductive film of an indium-tin composite oxide laminated on one surface of the substrate, wherein the transparent conductive film has an on-resistance of 10 kOmega or less as a transparent conductive film obtained by the following pen sliding durability test, the transparent conductive film has a surface resistance value increasing rate of 1.5 or less as a transparent conductive film obtained by the following pen weight press test, and the sum of the transmission image vividness of the transparent conductive film at a comb width of 0.125mm, 0.25mm, 0.5mm, 1.0mm, and 2.0mm is 250% or more and less than 500%.
Description
Technical Field
The present invention relates to a transparent conductive film in which a transparent conductive film of a crystalline indium-tin composite oxide is laminated on a transparent plastic film substrate, and particularly relates to a transparent conductive film excellent in pen sliding durability, pen heavy pressure durability, and high precision when used in a resistive touch panel.
Background
Transparent conductive films obtained by laminating a transparent and low-resistance film on a transparent plastic substrate are widely used in the electric and electronic fields as applications utilizing the conductivity, for example, transparent electrodes of flat panel displays such as liquid crystal displays and Electroluminescence (EL) displays, and touch panels.
A resistive touch panel is a touch panel in which a fixed electrode formed by coating a transparent conductive thin film on a glass or plastic substrate and a movable electrode (= thin-film electrode) formed by coating a transparent conductive thin film on a plastic film are combined, and is used by being stacked on the upper side of a display body. The film electrode is pressed with a finger or a pen, and the transparent conductive films of the fixed electrode and the film electrode are brought into contact with each other, thereby making an input for position recognition of the touch panel. The force applied by the pen to the touch panel is mostly stronger than that of a finger. If an input is continuously made to the touch panel with a pen, a transparent conductive film on the film electrode side may be broken by a crack, peeling, abrasion, or the like. Further, when a strong force, which is assumed to be larger than that used in general, is applied to the touch panel, such as when the touch panel is strongly touched with a pen or when a pen input is performed with a very strong force, a crack, peeling, or the like may occur in the transparent conductive film. In order to solve these problems, a transparent conductive film having both excellent pen sliding durability and excellent pen re-pressurization durability is desired. Further, the image of the touch panel is also required to be highly precise.
As a means for improving the durability against sliding of the pen, there is a method of making a transparent conductive film on the film electrode side crystalline (for example, see patent document 1). However, the conventional transparent conductive thin film realizes a transparent conductive thin film having excellent pen sliding durability by controlling the crystallinity of the indium-tin composite oxide. However, the conventional transparent conductive film is insufficient when subjected to a pen-weight-application durability test described later.
Prior art documents
Patent document
Patent document 1: japanese patent laid-open publication No. 2004-071171
Disclosure of Invention
Problems to be solved by the invention
In view of the above-described conventional problems, an object of the present invention is to provide a transparent conductive film which has excellent pen sliding durability and excellent pen re-pressurization durability when used in a touch panel, and which can provide a high-definition image.
Means for solving the problem
The present invention has been made in view of the above circumstances, and a transparent conductive film of the present invention capable of solving the above problems has the following structure.
1. A transparent conductive film comprising a transparent plastic film substrate and a transparent conductive film of an indium-tin composite oxide laminated on one surface of the transparent conductive film, wherein the transparent conductive film has an on-resistance of 10k [ omega ] or less as obtained by the pen sliding durability test described below, and wherein the transparent conductive film has a surface resistance value increasing rate of 1.5 or less as obtained by the pen weight press test described below, and wherein the sum of transmission image vividness of the transparent conductive film at a comb width of 0.125mm, 0.25mm, 0.5mm, 1.0mm, or 2.0mm is 250% or more and less than 500%.
(Pen sliding durability test method)
The transparent conductive thin film was used as one panel, and as the other panel, a transparent conductive thin film containing an indium-tin composite oxide thin film (tin oxide content: 10 mass%) formed on a glass substrate by a sputtering method and having a thickness of 20nm was used. The 2 panels were placed with epoxy beads 30 μm in diameter so that the transparent conductive films were opposed to each other, and the panel on the film side and the panel on the glass side were bonded with a double-sided tape 170 μm in thickness to produce a touch panel. Next, a linear sliding test of 18 ten thousand reciprocating movements was performed on the touch panel by applying a load of 2.5N to a pen made of polyacetal (shape of tip: 0.8 mmR). In this test, a load of a pen was applied to the transparent conductive film surface.
The sliding distance was 30mm and the sliding speed was 180 mm/sec. After the sliding durability test, the on-resistance (resistance value when the movable electrode (thin film electrode) and the fixed electrode were in contact) when the sliding portion was pressed with a pen load of 0.8N was measured.
(Pen weight pressurization test method)
The transparent conductive thin film cut into 50mm × 50mm was used as one panel, and as the other panel, a transparent conductive thin film containing an indium-tin composite oxide thin film (tin oxide content: 10 mass%) formed on a glass substrate by a sputtering method and having a thickness of 20nm was used. The 2 panels were placed with epoxy beads 30 μm in diameter so that the transparent conductive films were opposed to each other, and the panel on the film side and the panel on the glass side were bonded with a double-sided tape adjusted to a thickness of 120 μm to produce a touch panel. A 35N load was applied to a position 2.0mm from the end of the double-sided tape by a polyacetal pen (shape of tip 0.8 mmR), and linear sliding was performed 10 times (5 times of reciprocation) in parallel with the double-sided tape. In this test, a pen load was applied to the transparent conductive film surface. The sliding distance was 30mm and the sliding speed was 20 mm/sec. Sliding was performed in the position where there was no epoxy bead. After sliding, the transparent conductive film was removed, and the surface resistance at any 5 places of the sliding part was measured (4-terminal method), and the average value was obtained. In the measurement of the surface resistance, 4 terminals were arranged in a direction perpendicular to the sliding portion so that the sliding portion appeared between the second terminal and the third terminal. The increase rate of the surface resistance value was calculated by dividing the average value of the surface resistance values of the sliding portions by the surface resistance value of the non-sliding portion (measured by the 4-terminal method).
2. The transparent conductive film according to the above item 1, wherein,
the transparent conductive film of indium-tin composite oxide has a crystal grain diameter of 10 to 100nm, a degree of crystallization of 20 to 80% and contains 0.5 to 10 mass% of tin oxideThe thickness of the transparent conductive film of the indium-tin composite oxide is 10 to 30nm, X is 1 to 100nm when the three-dimensional surface roughness SRa of the transparent conductive film of the indium-tin composite oxide is X, and Y is the three-dimensional surface roughness SRa of the surface opposite to the transparent conductive film side on the transparent plastic film substrate (X) 3 +Y 3 ) 1/3 Is 140nm or less.
3. The transparent conductive film according to the above 1 or 2, wherein,
even if an adhesion test (JIS K5600-5-6 1999) is performed on the surface of the transparent conductive film, the transparent conductive film is not peeled, and the mandrel diameter at which cracking or peeling occurs when the transparent conductive film side of the indium-tin composite oxide of the transparent conductive film is subjected to a bending resistance test (JIS K5600-5-1 1999) and the bent portion is observed with a 10-fold magnifying glass is less than 20mm.
4. The transparent conductive film according to any one of the above 1 to 3, wherein,
the thickness of the transparent conductive film is 100 to 250 μm.
5. The transparent conductive film according to any one of the above 1 to 4, wherein,
a curable resin layer is provided between a transparent conductive film of an indium-tin composite oxide and a transparent plastic film substrate.
Effect of the invention
According to the present invention, it is possible to provide a transparent conductive film which has both excellent pen sliding durability and excellent pen re-pressurization durability and can provide a high-definition image. The obtained transparent conductive thin film is extremely useful for applications such as a resistive touch panel.
Drawings
FIG. 1 is a schematic view showing one example (one of) longest portions of crystal grains in the present invention.
FIG. 2 is a schematic view showing another example (second example) of the longest portion of the crystal grain in the present invention.
FIG. 3 is a schematic view showing another example (third) of the longest portion of the crystal grain in the present invention.
FIG. 4 is a schematic view showing another example (fourth example) of the longest portion of the crystal grain in the present invention.
Fig. 5 is a schematic diagram for explaining the position of the center roller of an example of the sputtering apparatus preferably used in the present invention.
Detailed Description
The transparent conductive film of the present invention is a transparent conductive film in which a transparent conductive film of an indium-tin composite oxide is laminated on one surface of a transparent plastic film substrate, and the transparent conductive film of the transparent conductive film obtained by the following pen sliding durability test has an on-resistance of 10k Ω or less, and the transparent conductive film of the transparent conductive film obtained by the following pen weight press test has an increase rate of a surface resistance value of 1.5 or less, and the sum of transmission image vividness of the transparent conductive film at a comb width of 0.125mm, 0.25mm, 0.5mm, 1.0mm, and 2.0mm is preferably 250% or more and less than 500%.
(Pen sliding durability test)
The transparent conductive thin film according to the present invention was used as one panel, and as the other panel, a transparent conductive thin film including an indium-tin composite oxide thin film (tin oxide content: 10 mass%) formed on a glass substrate by a sputtering method and having a thickness of 20nm was used. The 2 panels were arranged with epoxy beads 30 μm in diameter so that the transparent conductive films were opposed to each other, and the panel on the film side and the panel on the glass side were bonded with a double-sided tape 170 μm in thickness to produce a touch panel. Next, a linear sliding test of 18 ten thousand reciprocating movements was performed on the touch panel by applying a load of 2.5N to a pen made of polyacetal (shape of tip: 0.8 mmR). In this test, a pen load was applied to the transparent conductive film surface according to the present invention. The sliding distance was 30mm and the sliding speed was 180 mm/sec. After the sliding durability test, the on-resistance (resistance value when the movable electrode (thin film electrode) and the fixed electrode were in contact) when the sliding portion was pressed with a pen load of 0.8N was measured.
(Pen weight pressure test)
The transparent conductive film according to the present invention was cut into 50mm × 50mm transparent conductive films for one panel, and an indium-tin composite oxide film (tin oxide content: 10 mass%) having a thickness of 20nm formed on a glass substrate by sputtering was used for the other panel. The 2 panels were arranged with epoxy beads 30 μm in diameter so that the transparent conductive films were opposed, and the panel on the film side and the panel on the glass side were bonded with a double-sided tape adjusted to a thickness of 120 μm to fabricate a touch panel. A 35N load was applied to a position 2.0mm from the end of the double-sided tape by a polyacetal pen (shape of tip 0.8 mmR), and linear sliding was performed 10 times (5 times of reciprocation) in parallel with the double-sided tape. In this test, a pen load was applied to the transparent conductive film surface according to the present invention. The sliding distance was 30mm and the sliding speed was 20 mm/sec. Wherein the sliding is performed at a position where there is no epoxy bead. After sliding, the transparent conductive film was removed, and the surface resistance at any 5 places of the sliding part was measured (4-terminal method), and the average value was obtained. In the measurement of the surface resistance, 4 terminals were arranged in a direction perpendicular to the sliding portion so that the sliding portion appeared between the second terminal and the third terminal. The increase rate of the surface resistance value was calculated by dividing the average value of the surface resistance values of the sliding portions by the surface resistance value of the non-sliding portion (measured by the 4-terminal method).
The transparent conductive film of the present invention is excellent in pen sliding durability and pen heavy pressurization durability. Pen sliding durability and pen re-pressurization durability are opposite properties. First, pen sliding durability will be explained. The transparent conductive film of the indium-tin composite oxide transparent conductive film having excellent pen sliding durability has a high crystallization degree and a large crystal particle diameter. The degree of crystallization and the crystal particle diameter are explained. A portion of a region having a circular or polygonal shape 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 an amorphous portion. A high degree of crystallization indicates a high proportion of crystals. The large crystal grain size means that the region of a circular or polygonal shape observed under a transmission electron microscope is large. Since the transparent conductive film having a high degree of crystallization has a high proportion of hard crystals and large strain around crystal grains having a large crystal grain size, the transparent conductive film becomes hard and has excellent pen-sliding durability. Next, the durability against the pen pressurization will be explained. The transparent conductive film of an indium-tin composite oxide having excellent durability against heavy pressure is required to have a low degree of crystallization of the transparent conductive film, a small crystal particle diameter, and further a small three-dimensional surface roughness of the transparent conductive film. As for the three-dimensional surface roughness, as will be described later, first, a transparent conductive film having a low degree of crystallization has a high proportion of soft and amorphous, and the strain around crystal grains of a transparent conductive film having a small crystal grain size is small, and therefore cracks and the like are less likely to occur even if a load is applied to the transparent conductive film, and the transparent conductive film has excellent durability against heavy pressure. As described above, the pen sliding durability and the pen re-pressurization durability are opposite properties. As a result of the investigation, it is possible to achieve both pen sliding durability and pen pressurization durability by controlling the crystallization degree and the crystal particle diameter of the transparent conductive film. A transparent conductive film having a transparent conductive film that can achieve both pen sliding durability and pen pressurization durability will be described.
In the present invention, it is preferable that the on-resistance of the transparent conductive film of the transparent conductive thin film based on the pen sliding durability test is 10k Ω or less because cracks, peeling, abrasion, and the like can be suppressed in the transparent conductive film even if a pen is continuously applied to the touch panel. In one embodiment, the on-resistance may be 9.5k Ω or less, and more preferably 5k Ω or less. For example, the on-resistance is 3k Ω or less, and may be 1.5k Ω or less, and preferably 1k Ω or less. If the on resistance is 0k Ω, the pen sliding durability is very excellent, and in the present invention, the on resistance may be 0k Ω. The on-resistance may be 3k Ω or more, or 5k Ω or more, for example.
By setting the on-resistance within such a range, even if a pen is used to continuously input to the touch panel, cracks, peeling, abrasion, and the like can be suppressed in the transparent conductive film.
In one embodiment, these upper and lower limits may be combined as appropriate.
In the present invention, the increase rate of the surface resistance value of the transparent conductive film by the pen weight pressure test is preferably 1.5 or less. By having such characteristics, for example, even if a strong force that is assumed to be used or more is applied, cracks, peeling, and the like can be suppressed in the transparent conductive film. The increase rate of the surface resistance value is more preferably 1.2 or less, and particularly preferably 1.0 (no increase).
Here, the increase rate of the surface resistance value of the transparent conductive film according to the present invention is preferably 1.0 or more.
In one embodiment, the on-resistance of the transparent conductive film in the pen sliding durability test is 0.05k Ω or more and 9.5k Ω or less, and the increase rate of the surface resistance value of the transparent conductive film in the pen weight pressurization (durability) test is 1.0 or more and 1.5 or less.
As described above, generally, the pen sliding durability and the pen re-pressurization durability are opposite properties. In the present invention, within such a range, both durability properties can be obtained in a well-balanced manner. Further, even if a pen is used to continuously input an input to the touch panel, the transparent conductive film can be prevented from being cracked, peeled, abraded, or the like, and excellent durability can be exhibited against a load due to sliding of the pen or heavy pressurization of the pen. In addition, the numerical range can be selected from the ranges and values described in the present specification.
In the present invention, it is preferable that the sum of the transmitted image vividness of the transparent conductive film at a comb width of 0.125mm, 0.25mm, 0.5mm, 1.0mm, 2.0mm is 250% or more and less than 500%, since a high-definition image can be provided. The larger the total sum of the sharpness of the transmitted image, the higher the sharpness of the image, i.e., the more excellent the high definition. More preferably, the total of the transmitted image sharpness of the transparent conductive film is 300% or more. Further preferably, the total of the transmitted image sharpness of the transparent conductive film is 400% or more.
In the present specification, the term "comb width" means the width of an optical comb according to JIS-K7105.
In the transparent conductive film of the present invention, the crystal grain size of the transparent conductive film of indium-tin composite oxide is preferably 10 to 100nm, and the degree of crystallization of the transparent conductive film of indium-tin composite oxide is preferably 20 to 80%. When the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 10nm or more, the transparent conductive film is suitably hardened due to strain around the crystal grains of the transparent conductive film, and therefore, the pen-sliding durability is excellent, which is preferable. More preferably, the crystal grain diameter of the transparent conductive film of the indium-tin composite oxide is 30nm or more.
On the other hand, when the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 100nm or less, the transparent conductive film is not too hard due to strain around the crystal grains of the transparent conductive film, and therefore, the durability against heavy pressure is excellent, which is preferable. More preferably, the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 90nm or less.
In one embodiment, the crystal grain size of the transparent conductive film of the indium-tin composite oxide is 30nm or more and 95nm or less, for example, 40nm or more and 90nm or less.
When the crystallization degree of the transparent conductive film of the indium-tin composite oxide is 20% or more, the transparent conductive film is suitably hardened due to hard crystals occupied in the transparent conductive film, and the pen-sliding durability is excellent. The crystallinity of the transparent conductive film of the indium-tin composite oxide is more preferably 25% or more. On the other hand, if the crystallization degree 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 excessively hard, and therefore, the pen-weight-pressing durability is excellent, which is preferable.
In one embodiment, the crystallinity of the transparent conductive film of indium-tin composite oxide is 25% or more and 78% or less, for example, 25% or more and 76% or less.
In the transparent conductive film of the present invention, when the three-dimensional surface roughness SRa of the transparent conductive film is X, X is preferably 1 to 100nm. When X is 1 to 100nm, the surface protrusion of the transparent conductive film is small, so that the amount of deformation of the surface protrusion is small when the pen weight press test is performed, the occurrence of cracks in the transparent conductive film is suppressed, and further, the surface protrusion is small on the transparent conductive film, so that the film windability can be maintained, which is preferable. More preferably, X is 1 to 80nm. More preferably, X is 1 to 65nm.
The transparent conductive film in the present invention contains an indium-tin composite oxide, and preferably contains 0.5 mass% to 10 mass% of tin oxide. Tin oxide in the indium-tin composite oxide corresponds to an impurity for indium oxide. The melting point of the indium-tin composite oxide increases by the impurities containing tin oxide. That is, the impurity content of tin oxide acts in a direction of inhibiting crystallization, and therefore is an important factor having a strong correlation with crystallinity such as a crystal grain diameter and a degree of crystallization. When tin oxide is contained in an amount of 0.5 mass% or more, the surface resistance of the transparent conductive film is preferably at a practical level. The content of tin oxide is more preferably 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 the semi-crystalline state described later is adjusted, and the pen sliding durability is preferable. The content of tin oxide is more preferably 8% by mass or less, still more preferably 6% by mass or less, and particularly preferably 4% by mass or less. The surface resistance of the transparent conductive film of the present invention is preferably 50 to 900 Ω/□, more preferably 50 to 600 Ω/□.
In the present invention, the thickness of the transparent conductive film is preferably 10nm or more and 30nm or less. The thickness of the transparent conductive film is an important factor having a strong correlation with crystallinity such as crystal grain size and crystallinity. When the thickness of the transparent conductive film is 10nm or more, the transparent conductive film is not excessively amorphous, and an appropriate crystal grain size and crystallization degree in a semi-crystalline state, which will be described later, are easily provided, and as a result, pen sliding durability is maintained. The thickness of the transparent conductive film is more preferably 13nm or more, and still more preferably 16nm or more. Further, when the thickness of the transparent conductive film is 30nm or less, the crystal grain size of the transparent conductive film is not excessively large, the degree of crystallization is not excessively high, the semi-crystal state is easily maintained, and the pen-weight pressurization durability is maintained. More preferably 28nm or less, and still more preferably 25nm or less.
In the transparent conductive film of the present invention, when the three-dimensional surface roughness SRa of the surface of the transparent plastic film substrate opposite to the transparent conductive film side is Y, (X) 3 +Y 3 ) 1/3 When the thickness is 140nm or less, the sum of the transmitted image vividness of the transparent conductive film at a comb width of 0.125mm, 0.25mm, 0.5mm, 1.0mm, or 2.0mm is 250% or more and less than 500%, and therefore, a high-definition image can be provided, which is preferable. ((X) 3 +Y 3 ) 1/3 Since the smaller the value of (b) is, the smaller the unevenness on both sides of the transparent conductive film is, it was confirmed that the transmitted image clarity tends to be high for improving the linearity of the incident light to the transparent conductive film. More preferably (X) 3 +Y 3 ) 1/3 Is 120nm or less. Further preferred is (X) 3 +Y 3 ) 1/3 Is 70nm or less. If (X) 3 +Y 3 ) 1/3 The thickness of 1nm or more is preferable because a slight surface protrusion is present on the transparent conductive film, and the film windability can be maintained.
The transparent conductive film of the present invention is preferably one in which the transparent conductive film does not peel off even when an adhesion test (JIS K5600-5-6. The transparent conductive film in which the transparent conductive film is not peeled off in the adhesion test is preferably a transparent conductive film in which the transparent conductive film is in close contact with a layer in contact with the transparent conductive film, such as a transparent plastic substrate or a curable resin layer, and therefore, even when a pen is continuously applied to the touch panel, cracks, peeling, abrasion, and the like can be suppressed in the transparent conductive film, and further, even when a strong force that is assumed to be used or more is applied, cracks, peeling, and the like can be suppressed in the transparent conductive film.
The transparent conductive film of the present invention is preferably one in which the mandrel diameter at which the crack or peeling occurs when the bent portion is observed with a 10-fold magnifying glass is less than 20mm by a bending resistance test (JIS K5600-5-1. If the diameter of the mandrel is less than 20mm, the layer in contact with the transparent conductive film is not broken when the pen weight test is performed, and no crack is generated in the transparent conductive film, which is preferable. More preferably 18mm or less.
In one embodiment, the value of the bending resistance test may be 1mm or more, for example, 8mm or more and 10mm or more. In one embodiment, the value of the bending resistance test is 13mm or more, and may be 15mm or more.
Within such a range, the layer in contact with the transparent conductive film is not broken when the pen weight test is performed, and no crack is generated in the transparent conductive film, which is preferable.
Further, a transparent conductive film having both excellent pen sliding durability and excellent pen heavy pressure durability can be provided.
The thickness of the transparent plastic film substrate of the transparent conductive film of the present invention is preferably in the range of 100 to 250. Mu.m, and more preferably 130 to 220. Mu.m. When the thickness of the plastic film is 100 μm or more, the mechanical strength is maintained, and particularly when the plastic film is used for a touch panel, deformation with respect to pen input is small, and pen sliding durability and pen heavy pressurization durability are excellent, so that the plastic film is preferable. On the other hand, when the thickness is 250 μm or less, it is not necessary to increase the load for positioning particularly in pen input when used for a touch panel.
The transparent conductive film in the present invention preferably has a curable resin layer between the transparent conductive film and the plastic film substrate. The presence of the curable resin layer is preferable because the increase in the adhesion of the transparent conductive film and the force applied to the transparent conductive film can be dispersed, and therefore, cracks, peeling, abrasion, and the like are suppressed in the transparent conductive film in the pen sliding test, and further, cracks, peeling, and the like are suppressed in the transparent conductive film in the pen heavy pressure test.
The crystallinity of the transparent conductive film in the present invention is in a state of not being too high or not being too low (such crystallinity is referred to as semicrystalline or semicrystalline structure). It is very difficult to stabilize the transparent conductive film to be semicrystalline. This is because a state in which the phase is stopped in the middle of rapid transition from amorphous to crystalline is semicrystalline. Therefore, the film formation atmosphere is sensitive to the amount of water in the film formation atmosphere, which is a parameter relating to crystallinity, and particularly sensitive to a hydrogen atom-containing gas, and even if the hydrogen atom-containing gas and the water content in the film formation atmosphere are slightly reduced, the film is substantially completely crystallized (high crystallinity), whereas if the hydrogen atom-containing gas and the water content in the film formation atmosphere are slightly increased, the film is amorphous (low crystallinity).
The method for producing the transparent conductive film of the present invention is not particularly limited, and the following production methods can be preferably exemplified.
As a method for forming a crystalline indium-tin composite oxide transparent conductive film on at least one surface of a transparent plastic film substrate, a sputtering method is preferably used. In order to produce a transparent conductive thin film with high productivity, a so-called roll sputtering apparatus is preferably used, in which a film roll is supplied and wound into a shape of a film roll after film formation. The following methods are preferably employed: in the film formation atmosphere, a gas containing a hydrogen atom (except for water, as long as it is a hydrogen atom-containing gas such as hydrogen, ammonia, a hydrogen + argon mixed gas, etc.) is introduced into a mass flow controller in an amount described below, and further, a film temperature at the time of sputtering is set to 0 ℃ or lower, a thickness of the transparent conductive film of the indium-tin composite oxide is adjusted to 10 to 30nm using a sintered target of indium-tin composite oxide containing 0.5 to 10 mass% of tin oxide, and the transparent conductive film is formed on a transparent plastic film of the indium-tin composite oxide in which a three-dimensional surface roughness SRa is 1 to 100nm. In the film formation atmosphere during sputtering, a hydrogen atom-containing gas has an 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 (which may be simply referred to as hydrogen concentration) is preferably 0.01 to 3.00%. The hydrogen concentration may be, for example, 0.01% or more and 2.00% or less, or 0.01% or more and 1.00% or less.
When the hydrogen concentration is in such a range, it can contribute to a favorable result in any of the pen sliding durability test on-resistance value and the pen re-pressurization durability test, for example.
Examples of the inert gas include helium, argon, krypton, and xenon. When a gas containing hydrogen atoms other than hydrogen gas is used, the amount of hydrogen atoms contained in the gas containing hydrogen atoms may be calculated in terms of the hydrogen gas (= hydrogen molecule) amount. When the gas containing hydrogen atoms is precisely flowed by the mass flow controller in the film forming atmosphere, the gas blowoff port is arranged so that the gas containing hydrogen atoms can be uniformly blown in the direction perpendicular to the longitudinal direction of the film roll, and the transparent conductive film in which the high-crystallinity part and the low-crystallinity part are not easily mixed is obtained, and thus the uniform semi-crystalline transparent conductive thin film can be suitably obtainedA transparent conductive film having excellent pen sliding durability and pen re-pressurizing durability. It is known that if the amount of water in the film forming atmosphere is large, the crystallinity of the transparent conductive film is reduced, and therefore the amount of water in the film forming atmosphere is also an important factor. When a gas containing hydrogen atoms is used, the central value (the value between the maximum value and the minimum value) of the ratio of the water partial pressure of the film-forming atmosphere to the inert gas during sputtering is controlled to 1.0X 10 -4 ～2.0×10 -3 Further, regarding the ratio of the water partial pressure of the film forming atmosphere to the inert gas in sputtering, if the difference between the maximum value and the minimum value from the start of film formation to the end of film formation is 1.0 × 10 -3 Hereinafter, since the uniformity of crystallinity of the transparent conductive film is maintained over the entire length of the thin film, it is preferable to perform a bombardment step described below, a limitation of the height difference of the irregularities of the film roll end surface described below, or the like, in addition to a rotary pump, a turbo molecular pump, and a cryopump which are frequently used as an exhaust device of a sputtering machine, that is, to reduce the amount of moisture released from the thin film at the time of forming the transparent conductive film and to release a uniform amount of moisture over the entire length of the thin film, because the precise control of the amount of moisture is not necessary. The central value of the ratio of the water partial pressure to the inert gas depends somewhat on the content of tin oxide in the transparent conductive film of the indium-tin composite oxide and the thickness of the transparent conductive film. When the amount of tin oxide added to the transparent conductive film of the indium-tin composite oxide is large, or when the transparent conductive film is thin, the central value of the ratio of the water partial pressure to the inert gas is preferably set to be low in the above range. Conversely, when the content of tin oxide in the transparent conductive film of the indium-tin composite oxide is small or when the transparent conductive film is thick, the center value of the ratio of the water partial pressure to the inert gas is preferably set to be high within the above range. The transparent conductive film is preferably formed on the transparent plastic film by setting the film temperature at sputtering to 0 ℃ or lower. The film temperature during film formation is replaced by the set temperature of a temperature controller for adjusting the temperature of the center roller in contact with the running film. Here, fig. 5 is a schematic view showing an example of a sputtering apparatus preferably used in the present invention, in which a traveling thin film 1 partially contacts with the surface of a center roll 2 and travels.An indium-tin sputtering target 4 is provided through a chimney 3, and a thin film of an indium-tin composite oxide is deposited and laminated on the surface of the thin film 1 running on the center roll 2. The center roller 2 is temperature-controlled by a temperature controller not shown. When the film temperature is 0 ℃ or lower, it is preferable because the release of impurity gases such as water and organic gases from the thin film that disperses the crystallinity of the transparent conductive film can be suppressed, and therefore, the crystallinity of the transparent conductive film is easily made uniform from the start of film formation to the end of film formation. When a gas containing hydrogen atoms is used, the center value (the value between the maximum value and the minimum value) of the ratio of the water partial pressure of the film-forming atmosphere to the inert gas during sputtering is preferably 1.0 × 10 -4 ～2.0×10 -3 . When the ratio of the water partial pressure of the film forming atmosphere to the inert gas in sputtering is within the above range, the inhibition of crystallinity of the transparent conductive film by the hydrogen atom-containing gas effectively acts, and therefore, it is preferable. In order to achieve a practical level of surface resistance and total light transmittance of the transparent conductive thin film, it is preferable to add oxygen during sputtering. This manufacturing method is mainly intended to eliminate as much as possible the influence of crystallinity due to water, which is an important factor for scattering the crystallinity of the transparent conductive film, and to control the crystallinity by a hydrogen-containing gas.
In controlling the moisture content when forming the indium-tin composite oxide on the plastic thin film, it is preferable to observe the moisture content at the time of actual film formation to be the following two reasons, compared with the observation of the degree of vacuum reached.
As the reason for this, at point 1, when a film is formed on a plastic film by sputtering, the film is heated and moisture is released from the film, so that the moisture content in the film forming atmosphere increases and is increased as compared with the measurement of the moisture content at the time of reaching the vacuum degree, and therefore, the moisture content at the time of film formation is expressed more accurately as compared with the expression at the time of reaching the vacuum degree.
The reason for this is that, in point 2, a large amount of transparent plastic film is put into the apparatus. In such an apparatus, a thin film is fed as a film roll. When the film is fed as a roll into a vacuum vessel, water in the outer layer portion of the roll is easily removed, but water in the inner layer portion of the roll is hardly removed. This is because the film roll is stopped when the measurement reaches the vacuum degree, but the film roll is moved during film formation, and therefore the inner layer portion of the film roll containing a large amount of water is wound up, and therefore the moisture content in the film forming atmosphere increases and increases compared with the moisture content when the measurement reaches the vacuum degree. In the present invention, when the amount of water in the film forming atmosphere is controlled, it is possible to preferably cope with this by observing the ratio of the water partial pressure of the film forming atmosphere to the inert gas during sputtering.
Preferably, the thin film is subjected to a bombardment step before forming the transparent conductive film. The bombardment step is a step of generating plasma by applying a voltage to discharge while only an inert gas such as argon or a mixed gas of a reactive gas such as oxygen and an inert gas is introduced. Specifically, the thin film is preferably bombarded by RF sputtering with an SUS target or the like. Since the thin film is exposed to plasma in the bombardment step, water and organic components are released from the thin film, and water and organic components released from the thin film are reduced when the transparent conductive film is formed, and therefore, crystallinity of the transparent conductive film is easily uniformized from the start of film formation to the end of film formation, which is preferable. Further, since the layer to which the transparent conductive film is in contact is activated by the bombardment step, the adhesion of the transparent conductive film is improved, and thus the pen sliding durability and the pen re-pressurizing durability are improved.
In the film roller for forming the transparent conductive film, the difference in height between the most convex portion and the most concave portion in the roller end surface is preferably 10mm or less. When the thickness is 10mm or less, the thickness is preferably set so that the crystallinity of the transparent conductive film from the start of film formation to the end of film formation is easily made uniform because the unevenness of the method of releasing water and organic components from the film end surface is reduced when the film roll is put into the sputtering apparatus.
In the method of forming a transparent conductive film of a crystalline indium-tin composite oxide on at least one surface of a transparent plastic film substrate, it is preferable to introduce oxygen gas during sputtering. When oxygen is introduced during sputtering, defects due to lack of oxygen in the transparent conductive film of the indium-tin composite oxide do not occur, the surface resistance of the transparent conductive film is low, and the total light transmittance is preferably high. Therefore, in order to achieve a practical level of surface resistance and total light transmittance of the transparent conductive thin film, it is preferable to introduce oxygen gas during sputtering. In addition, the total light transmittance of the transparent conductive film of the present invention is preferably 70 to 95%.
The transparent conductive film of the present invention is preferably formed by laminating a transparent conductive film of an indium-tin composite oxide on a transparent plastic film substrate and then subjecting the film to a heat treatment at 80 to 200 ℃ for 0.1 to 12 hours in an oxygen-containing atmosphere. When the temperature is 80 ℃ or higher, handling for slightly improving crystallinity to form a semi-crystalline state is easy, and pen sliding durability is improved, which is preferable. When the temperature is 200 ℃ or lower, the flatness of the transparent plastic film is preferably ensured.
< transparent Plastic film substrate >
The transparent plastic film substrate used in the present invention is a film obtained by melt-extruding or solution-extruding an organic polymer in a film form, and stretching, cooling and heat-fixing it in the longitudinal direction and/or the width direction as necessary, and examples of the organic polymer include polyethylene, polypropylene, polyethylene terephthalate, polyethylene 2,6-naphthalene dicarboxylate, polypropylene terephthalate, polybutylene terephthalate, nylon 6, nylon 4, nylon 66, nylon 12, polyimide, polyamideimide, polyether sulfone, polyether ether ketone, polycarbonate, polyarylate, cellulose propionate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyether imide, polyphenylene sulfide, polyphenylene oxide, polystyrene, syndiotactic polystyrene, and norbornene-based polymers.
Among these organic polymers, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene 2,6-naphthalate, syndiotactic polystyrene, norbornene polymer, polycarbonate, polyarylate and the like are preferable. In addition, these organic polymers may be obtained by copolymerizing a small amount of monomers of other organic polymers or by blending 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, or the like, on the film, as long as the object of the present invention is not impaired.
When the curable resin layer is applied to the transparent plastic film substrate, the transparent conductive film and the curable resin layer are firmly adhered to each other or a force applied to the transparent conductive film is dispersed, and therefore, cracks, peeling, abrasion, and the like can be suppressed in the transparent conductive film in the pen sliding test, and further, cracks, peeling, and the like can be suppressed in the transparent conductive film in the pen re-pressurization test, which is preferable. Further, when the transparent conductive film is formed on the surface of the curable resin layer with the irregularities, the actual contact area when the transparent conductive film and the glass are in contact with each other in the pen sliding test is reduced, so that the sliding property between the glass surface and the transparent conductive film is improved, the pen sliding durability is improved, and the improvement of the take-up property of the film roll and the newton ring resistance can be expected. Therefore, when the three-dimensional surface roughness SRa of the transparent conductive film is X, it is preferable that X is 1 to 100nm as the surface unevenness. The curable resin layer may be coated on both surfaces of the transparent plastic film substrate. When the three-dimensional surface roughness SRa of the curable resin layer on the surface opposite to the surface on which the transparent conductive film is formed is Y, Y is preferably 1 to 139nm. The curable resin layer will be described in detail below.
The curable resin layer preferably used in the present invention is not particularly limited as long as it is a resin that is cured by energy application such as heating, ultraviolet irradiation, electron beam irradiation, and the like, and examples thereof include silicone resin, acrylic resin, methacrylic resin, epoxy resin, melamine resin, polyester resin, polyurethane resin, and the like. From the viewpoint of productivity, it is preferable to use an ultraviolet curable resin as the main component.
Examples of such an ultraviolet curable resin include polyfunctional acrylate resins such as acrylic acid or methacrylic acid ester of polyol, and polyfunctional urethane acrylate resins synthesized from diisocyanate, polyol, hydroxyalkyl ester of acrylic acid or methacrylic acid, and the like. If necessary, a monofunctional monomer such as vinyl pyrrolidone, methyl methacrylate, styrene, or the like may be added to these polyfunctional resins to copolymerize them.
In addition, 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 irradiated to increase carbonyl groups, carboxyl groups, and hydroxyl groups; chemical treatment methods in which a polar group such as an amino group, a hydroxyl group, or a carbonyl group is increased by treatment with an acid or a base.
The ultraviolet curable resin is usually used with a photoinitiator added. As the photoinitiator, known compounds that absorb ultraviolet rays and generate radicals can be used without particular limitation, and examples of such photoinitiators include various benzoins, benzophenones, and the like. The amount of the photoinitiator added is preferably 1 to 5 parts by mass per 100 parts by mass of the ultraviolet-curable resin.
In the present invention, it is preferable that the curable resin layer and the functional layer contain both inorganic particles and organic particles in addition to the curable resin as a main constituent. By dispersing inorganic particles and organic particles in the curable resin, irregularities can be formed on the surfaces of the curable resin layer and the functional layer, and the surface roughness in a wide region can be improved.
Examples of the inorganic particles include silica and the like. Examples of the organic particles include polyester resins, polyolefin resins, polystyrene resins, polyamide resins, and the like.
In addition to the inorganic particles and the organic particles, it is preferable to use a resin incompatible with the curable resin in addition to the curable resin as a main constituent. By using a small amount of the incompatible resin in the matrix of the 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 form irregularities on the surface of the curable resin layer, and the surface roughness in a wide range can be improved.
Examples of the immiscible resin include polyester resins, polyolefin resins, polystyrene resins, and polyamide resins.
Here, the blending ratio in the case where inorganic particles are used in the curable resin layer directly below the transparent conductive film is shown as an example. 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 amount of the inorganic particles is 0.1 to 30 parts by mass per 100 parts by mass of the ultraviolet curable resin, the amount of the inorganic particles is preferably not too small because the projections formed on the surface of the curable resin layer are not too small, the occurrence of cracks in the transparent conductive film is suppressed, a high-definition image can be provided, and further, the surface of the transparent conductive film is slightly protruded, and the film windability can be maintained.
Here, the blending ratio in the case where inorganic particles are used for the curable resin layer on the side opposite to the side on which the transparent conductive film is formed is shown as an example. The amount of the inorganic particles is preferably 0.1 to 25 parts by mass, more preferably 0.1 to 15 parts by mass, and particularly preferably 0.1 to 12 parts by mass per 100 parts by mass of the ultraviolet-curable resin. When the amount of the inorganic particles is 0.1 to 25 parts by mass per 100 parts by mass of the ultraviolet curable resin, the amount of the inorganic particles is preferably small because the protrusions formed on the surface of the curable resin layer are small enough to effectively impart three-dimensional surface roughness and provide a high-definition image, and further, the surface of the transparent conductive film is slightly protruded, so that the film windability is maintained.
The ultraviolet-curable resin, the photoinitiator, and the inorganic particles, organic particles, and resin immiscible with the ultraviolet-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 ethanol and isopropyl alcohol, ester solvents such as ethyl acetate and butyl acetate, ether solvents such as dibutyl ether and ethylene glycol monoethyl ether, ketone solvents such as methyl isobutyl ketone and cyclohexanone, and aromatic hydrocarbon solvents such as toluene, xylene and solvent naphtha.
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 total amount of the ultraviolet curable resin, the photoinitiator, and the high molecular weight polyester resin is usually 20 to 80% by mass in the coating liquid. If necessary, other known additives, for example, a silicone leveling agent and the like, 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 a bar coating method, a gravure coating method, and a reverse coating method can be used.
The coating liquid after coating is subjected to solvent evaporation and removal in the subsequent drying step. In this step, the high molecular weight polyester resin uniformly dissolved in the coating liquid becomes particles and precipitates in the ultraviolet curable resin. After the coating film is dried, the plastic film is irradiated with ultraviolet rays, thereby crosslinking/curing the ultraviolet-curable resin to form a curable resin layer. In the curing step, the particles of the high molecular weight polyester resin are fixed in the hard coat layer, and protrusions are formed on the surface of the curable resin layer, thereby improving the surface roughness in a wide region.
The thickness of the curable resin layer is preferably in the range of 0.1 to 15 μm. More preferably in the range of 0.5 to 10 μm, and particularly preferably in the range of 1 to 8 μm. When the thickness of the curable resin layer is 0.1 μm or more, it is preferable to form a sufficient protrusion. On the other hand, a thickness of 15 μm or less is preferable because productivity is good.
Examples
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, various measurement evaluations in the examples were performed by the following methods.
(1) Total light transmittance
According to JIS-K7361-1:1997, NDH-2000 manufactured by Nippon Denshoku industries Co., ltd., was used to measure the total light transmittance.
(2) Surface resistance value
According to JIS-K7194:1994, measured by the 4-terminal method. The measuring machine used Lotetta AX MCP-T370 manufactured by Mitsubishi Chemical analysis technology (Mitsubishi Chemical Analyticch Co., ltd.).
(3) Three-dimensional center plane average surface roughness SRa
The three-dimensional center plane average surface roughness SRa was determined by Bert's scanning (R5500H-M100 manufactured by Trapa system, inc. (measurement conditions: wave mode, measurement wavelength 560nm, objective lens magnification)) using a three-dimensional surface texture measuring apparatus specified in ISO 25178. The number of measurements was set to 5, and the average value of these measurements was obtained. Here, the first decimal place in nm units is rounded. Here, the three-dimensional surface roughness SRa of the transparent conductive film is X, and the three-dimensional surface roughness SRa of the surface of the transparent plastic film substrate opposite to the transparent conductive film side is Y.
(4) Crystal grain size
A film sample sheet on which a transparent conductive thin film layer is laminated is cut into a size of 1mm × 10mm, and the conductive thin film is attached to the upper surface of an appropriate resin block with the conductive thin film surface facing outward. After trimming, an ultra-thin section is produced substantially parallel to the surface of the film by a common microtome technique.
The surface portion of the conductive film where the cut piece was observed with a transmission electron microscope (JEOL Ltd., JEM-2010) without significant damage was selected, and photographed at an accelerating voltage of 200kV and a direct magnification of 40000 times.
The longest part of all crystal grains among the crystal grains observed under the transmission electron microscope was measured, and the average of the measured values was defined as the crystal grain diameter. Here, fig. 1 to 4 show an example of a method of determining the longest portion when measuring the longest portion of the crystal grain. That is, the longest portion is determined by the length of a straight line that can measure the grain size of each crystal grain to the maximum.
(5) Thickness of transparent conductive film (film thickness)
A thin film sample piece having a transparent conductive thin film layer laminated thereon was cut into a size of 1mm × 10mm and embedded in an epoxy resin for an electron microscope. This was fixed to a sample holder of an microtome, and a thin section parallel to the short side of the embedded sample piece was prepared. Then, a transmission electron microscope (JEOL, JEM-2010) was used to photograph the sliced thin film at an accelerating voltage of 200kV and at an observation magnification of 1 ten thousand times in the bright field, and the film thickness was determined from the obtained photograph.
(6) Pen sliding durability test
The transparent conductive thin film according to the present invention was used as one panel, and as the other panel, a transparent conductive thin film including an indium-tin composite oxide thin film (tin oxide content: 10 mass%) formed on a glass substrate by a sputtering method and having a thickness of 20nm was used. The 2-piece panel was placed with epoxy beads 30 μm in diameter so that the transparent conductive films were opposed to each other, to produce a touch panel. Next, a linear sliding test of 18 ten thousand cycles was performed on the touch panel by applying a load of 5.0N to a polyacetal pen (tip shape: 0.8 mmR). In this test, a pen load was applied to the transparent conductive film surface according to the present invention. The sliding distance was 30mm and the sliding speed was 180 mm/sec. After the sliding durability test, the on-resistance (resistance value when the movable electrode (thin film electrode) and the fixed electrode were in contact) when the sliding portion was pressed with a pen load of 0.8N was measured. The on-resistance is preferably 10k Ω or less.
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 weight pressure test
The transparent conductive film according to the present invention was cut into 50mm × 50mm transparent conductive films for one panel, and an indium-tin composite oxide film (tin oxide content: 10 mass%) having a thickness of 20nm formed on a glass substrate by sputtering was used for the other panel. The 2 panels were placed with epoxy beads 30 μm in diameter so that the transparent conductive films were opposed to each other, and a panel on the film side and a panel on the glass side were bonded with a double-sided tape adjusted to a thickness of 120 μm to produce a touch panel. A 35N load was applied to a position 2.0mm from the end of the double-sided tape by a polyacetal pen (shape of tip 0.8 mmR), and linear sliding was performed 10 times (5 times of reciprocation) in parallel with the double-sided tape. In this test, a pen load was applied to the transparent conductive film surface according to the present invention. The sliding distance was 30mm and the sliding speed was 20 mm/sec. Wherein the sliding is performed at a position where there is no epoxy bead. After the sliding, the transparent conductive film was removed, and the surface resistance at any 5 points of the sliding part was measured (4-terminal method), and the average value was obtained. In the measurement of the surface resistance, 4 terminals were arranged in a direction perpendicular to the sliding portion so that the sliding portion appeared between the second terminal and the third terminal. The increase rate of the surface resistance value was calculated by dividing the average value of the surface resistance values of the sliding portions by the surface resistance value of the non-sliding portion (measured by the 4-terminal method).
In comparative examples, the film of each comparative example was used in place of the transparent conductive film according to the present invention.
(8) Measurement of content of tin oxide contained in transparent conductive film
Samples (about 15 cm) were cut 2 ) In a quartz Erlenmeyer flask, 20ml of 6mol/l hydrochloric acid was added, and the flask was sealed with a thin film without volatilization of the acid. The transparent conductive film was allowed to stand for 9 days while being shaken at room temperature at all times to dissolve the transparent conductive film. The residual film was taken out, and hydrochloric acid in which the transparent conductive film was dissolved was used as a measurement solution. In and Sn In the solution were determined by a calibration curve method using an ICP emission spectrometer (trade name; science, apparatus type; CIROS-120 EOP). The measurement wavelength of each element is selected to have high sensitivity without interference. The standard solution was prepared using commercially available In and Sn standard solutions.
(9) Adhesion test
According to JIS K5600-5-6: 1999.
(10) Bending resistance test
According to JIS K5600-5-1: 1999. When the mandrel diameter did not break or peel until 13mm, the above bending resistance test was not performed, and all of them are described as 13mm.
(11) Transmission image sharpness test
The transmission image clarity of the transparent conductive film at the comb widths of 0.125mm, 0.25mm, 0.5mm, 1.0mm and 2.0mm was measured in accordance with JIS-K7105, and the sum of the transmission image clarity of each comb width was determined. The measuring machine used was an image measuring instrument ICM-1T manufactured by Suga testing machine (Co.).
The transparent plastic film substrates used in the examples and comparative examples were biaxially oriented transparent PET films having easy-adhesive layers on both sides (a 4380, manufactured by toyobo co., ltd., thickness is shown in tables 1 and 2). As the curable resin layer, silica particles (snowtex zl, manufactured by SEIKA corporation) in the amounts shown in tables 1 and 2 were mixed with 100 parts by mass of an acrylic resin containing a photoinitiator (manufactured by sun chemical industries, inc., SEIKA beam (registered trademark)) and a mixed solvent of toluene/MEK (8/2: mass ratio) was added as a solvent so that the solid content concentration became the values shown in tables 1 and 2, and the mixture was stirred and dissolved uniformly to prepare a coating liquid (hereinafter, this coating liquid is referred to as coating liquid a). The prepared coating liquid was coated using a Meyer bar so that the thickness of the coating film was 5 μm. After drying at 80 ℃ for 1 minute, the plate was irradiated with ultraviolet light (light quantity: 300 mJ/cm) using an ultraviolet irradiation apparatus (model UB042-5AM-W, manufactured by EYEGRAPHICS, inc.) 2 ) And curing the coating film. The curable resin layers are provided on both surfaces of the transparent plastic substrate.
(examples 1 to 8)
The levels of the examples were as follows under the conditions shown in Table 1.
Putting the film into a vacuum tank, and vacuumizing to 1.5 × 10 -4 Pa. Next, after oxygen was introduced, argon as an inert gas and hydrogen as a hydrogen-containing gas were introduced at concentrations shown in table 1 so that the total pressure was 0.6Pa.
At 3W/cm 2 The power density of (2) is obtained by applying electric power to a sintered target of indium-tin composite oxide or a sintered target of indium oxide containing no tin oxide, and forming a transparent conductive film by a DC magnetron sputtering method. The film thickness is controlled by changing the speed of the thin film passing over the target. In addition, the ratio of water partial pressure of film forming atmosphere to inert gas during sputtering was usedThe measurement was performed by a gas analyzer (trade name: transreactor XPR3, inficon). At each level of examples, in order to adjust the ratio of the water partial pressure of the film forming atmosphere to the inert gas during sputtering, as shown in table 1, the temperature of the heat medium of the temperature controller was adjusted so as to control the presence or absence of the bombardment step, the difference in level of the irregularities on the end surface of the film roll, and the temperature of the thin film contacting the center roll during the travel. Table 1 shows the temperature at the very middle of the maximum value and the minimum value of the temperatures from the start of film formation on the film roll to the end of film formation as the center value.
The film on which the transparent conductive film was formed and laminated was subjected to the heat treatment described in table 1, and then measured. The measurement results are shown in table 1.
Comparative examples 1 to 9
Transparent conductive films were produced and evaluated under the conditions shown in table 1 in the same manner as in example 1. In comparative example 7, no curable resin layer was provided. In comparative example 8, the thickness of the coating film of the curable resin layer was adjusted to 20 μm. The results are shown in Table 2.
[ Table 1A ]
[ Table 1B ]
[ Table 2A ]
[ Table 2B ]
As shown in tables 1A and 1B, the transparent conductive films described in examples 1 to 8 were excellent in pen sliding durability, pen re-pressurization durability, and high fineness, and had all the characteristics. However, as shown in table 2, comparative examples 1 to 9 cannot all satisfy the pen sliding durability, the pen re-pressurizing durability, and the high fineness.
Industrial availability-
As described above, according to the present invention, a transparent conductive film having excellent pen sliding durability, pen pressurization durability, and high definition can be produced, and this is extremely useful for applications such as a resistive film type touch panel.
Description of reference symbols
1. Film(s)
2. Center roller
3. Chimney
4. A target of indium-tin composite oxide.
Claims (5)
1. A transparent conductive film comprising a transparent plastic film substrate and a transparent conductive film of an indium-tin composite oxide laminated on one surface of the transparent conductive film, wherein the transparent conductive film of the transparent conductive film obtained by the following pen sliding durability test has an on-resistance of 10 kOmega or less, the transparent conductive film of the transparent conductive film obtained by the following pen weight press test has a surface resistance increasing rate of 1.5 or less, and the sum of transmission image vividness of the transparent conductive film at a comb width of 0.125mm, 0.25mm, 0.5mm, 1.0mm, and 2.0mm is 250% or more and less than 500%,
in the pen sliding durability test method,
the transparent conductive film was used as one panel, and as the other panel, a transparent conductive film comprising an indium-tin composite oxide film formed on a glass substrate by a sputtering method and having a thickness of 20nm and a tin oxide content of 10 mass%,
2 of the panels were arranged with epoxy beads 30 μm in diameter so that the transparent conductive films were opposed to each other, and the panel on the film side and the panel on the glass side were bonded with a double-sided tape 170 μm in thickness to produce a touch panel,
then, a linear sliding test of 18 ten thousand reciprocating movements was performed on a touch panel by applying a load of 2.5N to a polyacetal pen having a tip shape of 0.8mmR,
in this test, a pen load was applied to the transparent conductive film surface, the sliding distance was 30mm, the sliding speed was 180 mm/sec,
after the sliding durability test, the on-resistance when the sliding portion was pressed with a pen load of 0.8N, which is the resistance value when the movable electrode as the thin film electrode was in contact with the fixed electrode, was measured,
in the pen re-pressurization test method,
the transparent conductive film cut into 50mm × 50mm was used as one panel, and as the other panel, a transparent conductive film comprising an indium-tin composite oxide film formed by a sputtering method on a glass substrate and having a thickness of 20nm and a tin oxide content of 10 mass%,
2 of the panels were arranged with epoxy beads 30 μm in diameter so that the transparent conductive films were opposed to each other, and the panel on the film side and the panel on the glass side were bonded with a double-sided tape adjusted to a thickness of 120 μm to produce a touch panel,
A35N load was applied to a position 2.0mm from the end of the double-sided tape by a polyacetal pen having a tip shape of 0.8mmR, and linear sliding was performed 10 times, that is, 5 times in a reciprocating manner in parallel with the double-sided tape,
in this test, a pen load was applied to the transparent conductive film surface, the sliding distance was 30mm, the sliding speed was 20 mm/sec,
sliding the film at the position where no epoxy beads are present, removing the transparent conductive film after sliding, measuring the surface resistance at any 5 positions of the sliding part by the 4-terminal method to obtain an average value,
in measuring the surface resistance, 4 terminals were arranged in a direction perpendicular to the sliding part so that the sliding part appeared between the second terminal and the third terminal,
the increase rate of the surface resistance value was calculated by dividing the average value of the surface resistance values of the sliding portions by the surface resistance value of the non-sliding portion measured by the 4-terminal method.
2. The transparent conductive film according to claim 1,
the crystal grain diameter of the transparent conductive film of the indium-tin composite oxide is 10-100 nm, the crystallization degree of the transparent conductive film of the indium-tin composite oxide is 20-80%, the transparent conductive film of the indium-tin composite oxide contains 0.5-10% by mass of tin oxide, the thickness of the transparent conductive film of the indium-tin composite oxide is 10-30 nm,
when the three-dimensional surface roughness SRa of the transparent conductive film of the indium-tin composite oxide is X, X is 1 to 100nm, and when the three-dimensional surface roughness SRa of the surface opposite to the transparent conductive film side on the transparent plastic film substrate is Y, (X) 3 +Y 3 ) 1/3 Is 140nm or less.
3. The transparent conductive film according to claim 1 or 2,
even if the adhesion test is carried out on the surface of the transparent conductive film, JIS K5600-5-6:1999, the transparent conductive film was not peeled off, and the bending resistance test JIS K5600-5-1:1999 and observe the mandrel diameter at the bend with a 10-fold magnifying glass, which causes cracking or peeling, to be less than 20mm.
4. The transparent conductive film according to any one of claims 1 to 3,
the thickness of the transparent conductive film is 100 to 250 μm.
5. The transparent conductive film according to any one of claims 1 to 4,
a curable resin layer is provided between a transparent conductive film of an indium-tin composite oxide and a transparent plastic film substrate.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020163453 | 2020-09-29 | ||
| JP2020-163453 | 2020-09-29 | ||
| PCT/JP2021/029153 WO2022070609A1 (en) | 2020-09-29 | 2021-08-05 | Transparent conductive film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115769315A true CN115769315A (en) | 2023-03-07 |
Family
ID=80951347
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202180044765.3A Pending CN115769315A (en) | 2020-09-29 | 2021-08-05 | Transparent conductive film |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPWO2022070609A1 (en) |
| CN (1) | CN115769315A (en) |
| TW (1) | TW202219989A (en) |
| WO (1) | WO2022070609A1 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4975897B2 (en) * | 2000-08-03 | 2012-07-11 | 東洋紡績株式会社 | Transparent conductive film, transparent conductive sheet and touch panel |
| JP2002343150A (en) * | 2001-05-22 | 2002-11-29 | Mitsui Chemicals Inc | Transparent electric conductive film and its manufacturing method |
-
2021
- 2021-08-05 WO PCT/JP2021/029153 patent/WO2022070609A1/en active Application Filing
- 2021-08-05 CN CN202180044765.3A patent/CN115769315A/en active Pending
- 2021-08-05 JP JP2021549297A patent/JPWO2022070609A1/ja active Pending
- 2021-09-27 TW TW110135760A patent/TW202219989A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO2022070609A1 (en) | 2022-04-07 |
| TW202219989A (en) | 2022-05-16 |
| JPWO2022070609A1 (en) | 2022-04-07 |
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