CN116762145A - Transparent conductive film - Google Patents
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- CN116762145A CN116762145A CN202280009958.XA CN202280009958A CN116762145A CN 116762145 A CN116762145 A CN 116762145A CN 202280009958 A CN202280009958 A CN 202280009958A CN 116762145 A CN116762145 A CN 116762145A
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
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- 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
-
- 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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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
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- General Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Human Computer Interaction (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Non-Insulated Conductors (AREA)
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Abstract
Disclosed is a transparent conductive film which contains metal nanowires and has excellent conductivity and transparency. The transparent conductive film of the present invention is a transparent conductive film comprising a substrate and a transparent conductive layer disposed on one side of the substrate, wherein the transparent conductive layer comprises metal nanowires, and the amount x (g/m) of the metal nanowires in the transparent conductive layer 2 ) The relation with the conductivity y (1/Ω) of the transparent conductive film is the relation of the following formula (1): y=a×x (1). In formula (1), a is 0.77 or more.
Description
Technical Field
The present invention relates to a transparent conductive film.
Background
Conventionally, in an image display device having a touch sensor, a transparent conductive film obtained by forming a metal oxide layer such as ITO (Indium Tin Oxides; indium tin composite oxide) on a transparent resin film is often used as an electrode of the touch sensor. However, the transparent conductive film including the metal oxide layer has the following problems: the conductive property is easily lost by bending, and the conductive material is hardly used for applications requiring flexibility such as flexible displays.
On the other hand, as a transparent conductive film having high flexibility, a transparent conductive film including metal nanowires is known. The metal nanowires are wire-like conductive substances having a diameter of nanometer size. In a transparent conductive film made of metal nanowires, by forming the metal nanowires into a lattice shape, a good conductive path can be formed by a small number of metal nanowires, and an opening can be formed in a gap of the lattice, thereby realizing high light transmittance. As for the transparent conductive film containing such metal nanowires, there has been studied an improvement in conductivity essentially required for the conductive film.
Prior art literature
Patent literature
Patent document 1: japanese patent application laid-open No. 2009-505358
Patent document 2: japanese patent No. 6199034
Disclosure of Invention
Problems to be solved by the invention
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a transparent conductive film which includes metal nanowires and has excellent conductivity and transparency.
Means for solving the problems
The transparent conductive film of the present invention is a transparent conductive film comprising a substrate and a transparent conductive layer disposed on one side of the substrate, wherein the transparent conductive layer comprises metal nanowires, and the amount x (g/m) of the metal nanowires in the transparent conductive layer 2 ) The relation with the conductivity y (1/Ω) of the transparent conductive film is the relation of the following formula (1).
y＝a×x (1)
In formula (1), a is 0.77 or more.
In 1 embodiment, the transparent conductive film has a haze value of 20% or less.
In 1 embodiment, the surface resistance value of the transparent conductive film is 0.1 Ω/≡to 1000 Ω/≡.
In 1 embodiment, the amount of metal nanowires in the transparent conductive layer, x (g/m 2 ) Is 0.005g/m 2 ～0.05g/m 2 。
Effects of the invention
According to the present invention, a transparent conductive film containing metal nanowires and having excellent conductivity and transparency can be provided.
Drawings
Fig. 1 is a schematic cross-sectional view of a transparent conductive film obtained by the manufacturing method according to 1 embodiment of the present invention.
Detailed Description
A. Transparent conductive film
Fig. 1 is a schematic cross-sectional view of a transparent conductive film obtained by the manufacturing method according to 1 embodiment of the present invention. The transparent conductive film 100 includes a base material 10 and a transparent conductive layer 20 disposed on one side of the base material 10. The transparent conductive layer 20 includes metal nanowires (not shown).
The surface resistance value of the transparent conductive film is preferably 0.1 Ω/∈h to 1000 Ω/∈h, more preferably 0.5 Ω/∈h to 300 Ω/∈h, still more preferably 1 Ω/∈h to 200 Ω/∈h, particularly preferably 1 Ω/∈h to 150 Ω/∈h, and most preferably 20 Ω/∈h to 100 Ω/∈h. The surface resistance value can be measured by the "resistivity automatic measuring system MCP-S620 type MCP-S521 type" of Mitsubishi Chemical Analytech company.
The haze value of the transparent conductive film is preferably 20% or less, more preferably 10% or less, further preferably 0.1% to 5%, further preferably 0.1% to 3%, and particularly preferably 0.1% to 1%.
The total light transmittance of the transparent conductive film is preferably 30% or more, more preferably 35% or more, and particularly preferably 40% or more.
(transparent conductive layer)
As described above, the transparent conductive layer includes metal nanowires.
The amount x (g/m of the metal nanowire in the transparent conductive layer 2 ) The relation with the conductivity y (1/Ω) of the transparent conductive film is the relation of the following formula (1):
y＝a×x (1)
in formula (1), a is 0.77 or more. At the bookIn the invention, the metal nanowire is prepared by the method of adding the metal nanowire in the amount x (g/m 2 ) In the above relation with the conductivity y (1/Ω), a transparent conductive film remarkably excellent in conductivity can be obtained. The transparent conductive film of the present invention has a high conductivity while reducing the amount of metal nanowires used. Such a transparent conductive film is very advantageous in that high conductivity and transparency (low haze) can be achieved at the same time. Such a transparent conductive film can be obtained by the following steps as described below: the transparent conductive layer forming composition is applied to form a coating layer, and the coating layer is left for a predetermined time and then subjected to a blowing process in the next process. It is considered that by leaving the coating layer for a predetermined time, the flow of the metal nanowires in the coating layer can be preferably adjusted, and the contact points between the metal nanowires become large, so that the above-described effects can be obtained.
In the above formula (1), a is preferably 0.79 or more, more preferably 0.8 or more, still more preferably 0.85 or more, particularly preferably 0.88 or more, still more preferably 0.9 or more. In such a range, the above effect becomes more remarkable. The larger a is, the better, but its upper limit is, for example, 2.0. The greater the amount of silver, the higher the conductivity, but correspondingly the haze becomes higher, resulting in impaired transparency. Amount of metal nanowires x (g/m 2 ) Is present at every 1m 2 Weight of the metal nanowires of the transparent conductive layer. Conductivity is the inverse of the above surface resistance value.
Amount of metal nanowires in transparent conductive layer x (g/m 2 ) Preferably 0.005g/m 2 ～0.05g/m 2 More preferably 0.008g/m 2 ～0.03g/m 2 Further preferably 0.01g/m 2 ～0.025g/m 2 Particularly preferably 0.01g/m 2 ～0.02g/m 2 。
In 1 embodiment, the transparent conductive layer further comprises a polymer matrix. In this embodiment, metal nanowires are present in the polymer matrix. In a transparent conductive layer composed of a polymer matrix, the metal nanowires are protected by the polymer matrix. As a result, corrosion of the metal nanowire can be prevented, and a transparent conductive film having more excellent durability can be obtained.
The thickness of the transparent conductive layer is preferably 2 μm to 10 μm, more preferably 3 μm to 9 μm, and still more preferably 4 μm to 8 μm.
The content ratio of the metal nanowires in the transparent conductive layer is preferably 0.1 to 50 parts by weight, more preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the binder resin constituting the transparent conductive layer. When the content is in such a range, a transparent conductive film excellent in conductivity and light transmittance can be obtained.
The total light transmittance of the transparent conductive layer is preferably 85% or more, more preferably 90% or more, and even more preferably 95% or more.
The metal nanowire is a conductive substance made of metal, having a needle-like or linear shape, and having a diameter of nanometer. The metal nanowires may be linear or curved. When a transparent conductive layer made of metal nanowires is used, the metal nanowires are formed in a grid shape, so that a good conductive path can be formed even with a small number of metal nanowires, and a transparent conductive film having a small resistance can be obtained. Further, by forming the metal nanowires into a mesh shape and forming openings in the gaps of the mesh, a transparent conductive film having high light transmittance can be obtained.
The ratio of the thickness d to the length L (aspect ratio: L/d) of the metal nanowire is preferably 10 to 100000, more preferably 50 to 100000, particularly preferably 100 to 10000. If metal nanowires having a large aspect ratio are used in this manner, the metal nanowires cross each other well, and higher conductivity can be exhibited by a small number of metal nanowires. As a result, a transparent conductive film having high light transmittance can be obtained. In the present specification, "thickness of a metal nanowire" refers to a diameter of the metal nanowire when the cross section of the metal nanowire is circular, a minor diameter of the metal nanowire when the cross section of the metal nanowire is elliptical, and a longest diagonal line when the cross section of the metal nanowire is polygonal. The thickness and length of the metal nanowires can be confirmed by a scanning electron microscope or a transmission electron microscope.
The thickness of the metal nanowires is preferably less than 500nm, more preferably less than 200nm, particularly preferably 10nm to 100nm, and most preferably 10nm to 50nm. When the amount is in such a range, a transparent conductive layer having high light transmittance can be formed.
The length of the metal nanowire is preferably 1 μm to 1000 μm, more preferably 10 μm to 500 μm, and particularly preferably 10 μm to 100 μm. When the content is in such a range, a transparent conductive film having high conductivity can be obtained.
As the metal constituting the metal nanowire, any suitable metal may be used as long as it is a conductive metal. Examples of the metal constituting the metal nanowire include silver, gold, copper, and nickel. In addition, a material obtained by subjecting the above metals to plating treatment (for example, gold plating treatment) may be used. Among them, silver, copper or gold is preferable, and silver is more preferable from the viewpoint of conductivity.
As a method for producing the metal nanowire, any suitable method may be used. For example, there may be mentioned: a method of reducing silver nitrate in a solution; and a method in which a voltage or current is applied to the surface of the precursor from the tip of the probe, and the metal nanowire is pulled out from the tip of the probe, thereby continuously forming the metal nanowire. In the method for reducing silver nitrate in solution, silver salt such as silver nitrate is subjected to liquid phase reduction in the presence of polyhydric alcohol such as ethylene glycol and polyvinylpyrrolidone, thereby synthesizing silver nanowires. Silver nanowires of uniform size can be mass produced, for example, according to the methods described in Xia, Y. Et al, chem. Mater (2002), 14, 4736-4745, xia, Y. Et al, nano letters (2003) 3 (7), 955-960.
(substrate)
Any suitable material may be used as the material constituting the base material. Specifically, a polymer substrate such as a film or a plastic substrate is preferably used. This is because the smoothness of the substrate and wettability to the transparent conductive layer-forming composition are excellent, and the productivity can be greatly improved by continuous production using rolls.
The material constituting the base material is typically a polymer film containing a thermoplastic resin as a main component. Examples of the thermoplastic resin include polyester resins; cycloolefin resins such as polynorbornene; an acrylic resin; a polycarbonate resin; cellulose resin, and the like. Among them, polyester resins, cycloolefin resins, or acrylic resins are preferable. These resins are excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, and the like. The thermoplastic resin may be used alone or in combination of 2 or more. In addition, an optical film such as a low-retardation substrate, a high-retardation substrate, a retardation plate, a brightness enhancement film, or the like, which is used for a polarizing plate, may be used as a substrate.
The thickness of the base material is preferably 20 μm to 200. Mu.m, more preferably 30 μm to 150. Mu.m.
The total light transmittance of the base material is preferably 30% or more, more preferably 35% or more, and even more preferably 40% or more.
B. Method for producing transparent conductive film
In one embodiment, the method for producing a transparent conductive film of the present invention comprises: a coating step of forming a coating layer by coating a composition for forming a transparent conductive layer containing metal nanowires on a substrate; a setting step of setting the coating layer for a predetermined time; and a blowing step of blowing the coating layer after the placing step, whereby the transparent conductive film can be obtained, that is, a transparent conductive film comprising a base material and a transparent conductive layer disposed on one side of the base material. The above-described production method may include any suitable process other than the above-described coating process and blowing process. In one embodiment, the method may further include a drying step of drying the coating layer after the air blowing step. In another embodiment, the blowing step is a step of drying the coating layer, and the transparent conductive layer is formed through the blowing step.
In 1 embodiment, the above-described manufacturing method may be performed while conveying the substrate. Typically, the above-described coating step, the placing step, and the blowing step (and other steps such as a drying step, if necessary) are performed while the substrate in a roll state is discharged and conveyed, thereby forming an elongated transparent conductive film including the substrate and the transparent conductive layer disposed on one side of the substrate. In one embodiment, the transparent conductive film is wound after being formed.
As a method for transporting the substrate, any suitable method can be used. Examples thereof include conveyance by a conveyance roller, conveyance by a conveyance belt, and a combination thereof. The transport speed is, for example, 5m/min to 50m/min.
(coating step)
As described above, in the coating step, the composition for forming a transparent conductive layer including metal nanowires is applied to the substrate by any appropriate method to form a coating layer. In 1 embodiment, a transparent conductive layer-forming composition containing metal nanowires is applied to a long substrate while the substrate is being transported, thereby forming a coating layer.
The composition for forming a transparent conductive layer contains the metal nanowire. In 1 embodiment, the composition for forming a transparent conductive layer is prepared by dispersing metal nanowires in any appropriate solvent. Examples of the solvent include water, alcohol solvents, ketone solvents, ether solvents, hydrocarbon solvents, and aromatic solvents. The composition for forming a transparent conductive layer may further contain additives such as a resin (binder resin), a conductive material other than the metal nanowire (for example, conductive particles), and a leveling agent. The composition for forming a transparent conductive layer may contain additives such as plasticizers, heat stabilizers, light stabilizers, lubricants, antioxidants, ultraviolet absorbers, flame retardants, colorants, antistatic agents, compatibilizers, crosslinking agents, tackifiers, inorganic particles, surfactants, and dispersants.
The viscosity of the transparent conductive layer-forming composition is preferably 5 mPas/25 to 300 mPas/25 ℃, more preferably 10 mPas/25 to 100 mPas/25 ℃. In such a range, the effect of the present invention is remarkable. The viscosity of the transparent conductive layer-forming composition can be measured by a rheometer (for example, MCR302 of Anton Paar corporation).
The dispersion concentration of the metal nanowires in the composition for forming a transparent conductive layer is preferably 0.01 to 5 wt%. In such a range, the effect of the present invention is remarkable.
As a method for applying the composition for forming a transparent conductive layer, any suitable method can be used. Examples of the coating method include spray coating, bar coating, roll coating, die coating, inkjet coating, screen coating, dip coating, relief printing, gravure printing, and intaglio (gravure) printing.
The weight per unit area of the coating layer is preferably 0.3g/m 2 ～30g/m 2 More preferably 1.6g/m 2 ～16g/m 2 . In the case of such a range, the metal nanowires can be satisfactorily dispersed by the air blowing in the air blowing step, and a transparent conductive film having smaller conductive anisotropy can be produced.
The thickness Ts of the coating layer in the coating step is preferably 10 μm to 50. Mu.m, more preferably 13 μm to 40. Mu.m, still more preferably 13 μm to 30. Mu.m, particularly preferably 13 μm to 20. Mu.m. When the amount is in the above range, a transparent conductive film having particularly excellent conductivity can be obtained. The thickness Ts (hereinafter, also referred to as initial thickness Ts of the coating layer) refers to the thickness (wet thickness) of the coating layer immediately after the coating. The thickness of the coating layer, ts (wet thickness), can be measured by an optical interferometry film thickness meter (e.g., the "spectrometer FLAME-S" manufactured by ocean weight).
(placing step)
The depositing step is a step of depositing the coating layer for a predetermined time as described above. More specifically, the method is a step of placing a coating layer in an airless environment at 25 ℃ or less (preferably 20 to 25 ℃) to form a laminate including a substrate and the coating layer. In the present specification, the windless state refers to a state in which the wind speed (relative wind speed in the case of transporting the substrate) is less than 0.5 m/s. In addition, in the present specification, the term "placing" means that the thickness of the coating layer is reduced in a windless state, and is a concept including the following operations as well: the thickness of the coating layer is reduced while conveying a laminate structure including a substrate and the coating layer.
The time for placing the coating layer is, for example, 1 second to 300 seconds. The time for placing the coating layer corresponds to the time after the formation of the coating layer in the previous step and before the start of the air blowing in the subsequent step.
In the present invention, a transparent conductive film having excellent conductivity can be obtained by performing a blowing step in the next step after the coating layer is left for a predetermined time. When the transparent conductive film obtained by the above-described production method is compared with a transparent conductive film obtained by drying the coating layer without blowing or a transparent conductive film obtained by blowing the coating layer immediately after coating, the metal nanowires of the transparent conductive film obtained by the above-described production method have more excellent conductivity per unit weight. It is considered that, according to the manufacturing method of the present invention, by leaving the coating layer for a predetermined time, the flow of the metal nanowires in the coating layer can be preferably adjusted, and the contact points between the metal nanowires become large, so that the above-described effects can be obtained.
The thickness of the coating layer after the placing step (thickness Tb of the coating layer at the start of air blowing in the air blowing step) is preferably more than 1 μm, more preferably 2 μm or more. That is, the step of depositing is preferably terminated before the thickness of the coating layer is 1 μm or less (preferably, less than 2 μm). If this is done, the flow of the metal nanowires in the coating layer can be preferably adjusted, enabling more contact points of the metal nanowires with each other.
In 1 embodiment, the setting time is determined based on the thickness Ts of the coating layer in the coating process and the thickness of the coating layer after the setting process (the thickness Tb of the coating layer when the air blowing is started in the air blowing process). In 1 embodiment, the thickness Tb of the coating layer at the start of the air blowing in the air blowing step is 25% to 90%, more preferably 27% to 89%, and still more preferably 30% to 88% of the thickness Ts of the coating layer in the above-described coating step. In the case of such a range, the flow of the metal nanowires in the coating layer can be preferably adjusted, and the contact points between the metal nanowires become large, so that a transparent conductive film having high conductivity per unit weight of the metal nanowires can be obtained.
In 1 embodiment, the coating layer is preferably placed in a period of time until the thickness of the coating layer is 2 μm to 12 μm thinner than the initial thickness Ts of the coating layer, more preferably in a period of time until the thickness is 4 μm to 11 μm thinner than the initial thickness Ts of the coating layer, still more preferably in a period of time until the thickness is 6 μm to 10 μm thinner than the initial thickness Ts of the coating layer, and still more preferably in a period of time until the thickness is 6 μm to 9 μm thinner than the initial thickness Ts of the coating layer. In such a range, the flow of the metal nanowires in the coating layer can be preferably adjusted, and the number of contact points between the metal nanowires can be increased.
In addition, in the case where the initial thickness Ts of the coating layer is 10 μm to 13 μm, it is preferable to place the coating layer until the thickness Tb of the coating layer becomes 2.5 μm to 9 μm, and it is more preferable to place the coating layer until the thickness Tb of the coating layer becomes 3 μm to 5 μm. In the case where the initial thickness Ts of the coating layer exceeds 13 μm and falls below 16 μm, the coating layer is preferably placed until the thickness Tb of the coating layer becomes 4 μm to 12 μm, and more preferably placed until the thickness Tb of the coating layer becomes 5 μm to 7 μm. In the case where the initial thickness Ts of the coating layer exceeds 16 μm (preferably exceeds 16 μm and is 30 μm or less, more preferably exceeds 16 μm and is 20 μm or less), the coating layer is preferably placed until the thickness Tb of the coating layer becomes 6 μm to 14 μm, more preferably until the thickness Tb of the coating layer becomes 7 μm to 9 μm. In such a range, the flow of the metal nanowires in the coating layer can be preferably adjusted, and the number of contact points between the metal nanowires can be increased.
(air blowing step)
The air supply to the coating layer may be performed by any suitable method. In 1 embodiment, the air blowing to the coating layer can be performed by using an air blower disposed above (on the side opposite to the substrate) and/or on the side of the coating layer. The air blowing direction is set to any appropriate direction. For example, the air blowing direction may be set to have a predetermined angle (for example, 10 ° to 170 °) with respect to the coating layer surface, or may be set to be substantially parallel to the coating layer surface (for example, lower than 10 ° with respect to the coating layer surface). In addition, the wind blown spirally may be supplied. For example, a shutter (louver) may be provided in the blower, and the direction of the air flow may be adjusted by the direction of the shutter. In one embodiment, the direction of the air flow may be defined by the direction of the opening of the shutter. In the case of blowing helical wind, a blower having a helical wind direction plate at a blower opening may be used.
The wind speed of the wind is preferably 0.5 to 10m/s, more preferably 1 to 5m/s. When the content is in the above range, the metal nanowires can be well dispersed, and a transparent conductive film having excellent conductivity can be produced. In addition, a transparent conductive film excellent in surface smoothness and thickness uniformity can be obtained. The wind speed can be appropriately set according to the solvent or the like contained in the transparent conductive layer-forming composition. In the case of using a transparent conductive layer-forming composition prepared from water, the wind speed is preferably 0.5m/s to 10m/s, more preferably 1m/s to 5m/s. In the present specification, the wind speed means a wind speed at a point of time when the coating layer is reached.
The temperature of the air is preferably 10 to 50 ℃, more preferably 15 to 30 ℃. The wind speed can be appropriately set according to the solvent or the like contained in the transparent conductive layer-forming composition. In the case of using a transparent conductive layer-forming composition prepared from water, the temperature of the wind is preferably 10 to 50 ℃, more preferably 15 to 30 ℃. In the present specification, the temperature of the wind means the temperature of the wind at the time point when the coating layer is reached.
The blowing time is preferably 1 to 10 minutes, more preferably 2 to 5 minutes. When the content is in such a range, a transparent conductive film having a smaller conductive anisotropy can be produced with good dispersion of the metal nanowires. Specifically, if the blowing time is set to the above range and the blown area is defined, the metal nanowires can be appropriately dispersed throughout the coating layer. In addition, a transparent conductive film excellent in surface smoothness and thickness uniformity can be obtained.
In the air blowing step, the air blowing may be performed in multiple stages. For example, the air blowing may be performed stepwise in regions depending on the direction of the air, the wind speed, the temperature, and the like.
Any appropriate treatment may be performed after the air blowing step. For example, in the case of using a composition for forming a transparent conductive layer containing a binder resin, hardening treatment by ultraviolet irradiation or the like may be performed. In addition, the drying step may be performed after the air blowing step. Examples of the drying method include oven heating and natural drying.
Examples
Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The evaluation methods in the examples are as follows. The thickness was measured by an optical interferometer (optical spectrometer FLAME-S manufactured by ocean light).
(1) Surface resistance and conductivity
The surface resistance values (surface resistance values of MD and TD) of the transparent conductive film were measured by an eddy current method using a noncontact surface resistance meter (trade name "EC-80") manufactured by Napson corporation. The measurement temperature was set at 23 ℃. The inverse of the surface resistance value was obtained as the conductivity.
In addition, by { conductivity y (1/Ω)/every 1m 2 The amount x (g/m) of the metal nanowires 2 ) The formula of } is obtained by finding a (m) of the above-mentioned "y=a×x (1)" 2 /Ω·g)。
(2) Haze value
The haze value of the transparent conductive film was measured by a method specified in JIS 7136 using a haze meter (trade name "HN-150" manufactured by Country color science research Co., ltd.).
PREPARATION EXAMPLE 1 preparation of composition for Forming transparent conductive layer
Silver nanowires were synthesized based on the method described in chem. Mate. 2002, 14, 4736-4745.
The silver nanowires thus obtained were dispersed in pure water so that the concentration of the silver nanowires became 0.2 wt% and the concentration of the pentaethylene glycol dodecyl ether became 0.1 wt%, respectively, to obtain a composition for forming a transparent conductive layer.
Example 1
A PET film (trade name "S100" manufactured by mitsubishi resin) was used as the base material. While the substrate was conveyed by a conveying roller, the transparent electroconductive layer-forming composition prepared in production example 1 was applied to the substrate by a bar coater (product name "bar coater No.6", manufactured by first science Co., ltd.) to form a coating layer having a thickness (initial thickness of coating layer Ts) of 13 μm (i.e., every 1 m) 2 The amount x (g/m) of the metal nanowires 2 )＝0.012g/m 2 ). Then, the coating layer was left to stand until the thickness of the coating layer (thickness Tb of the coating layer at the start of blowing in the blowing step) became 9.1 μm (i.e., tb/ts=0.7) (leaving step). Then, air is blown from the center of the base material to both ends in the direction from the inner side in the width direction to both outer sides in the width direction. The angle between the conveyance direction of the substrate and the blowing direction (blowing direction viewed from the coating layer side) was set to 90 °, and the angle between the conveyance direction of the substrate and the blowing direction (blowing direction viewed from the coating layer side) was set to 0 °. The wind speed was set to 2m/s and the wind temperature was set to 25 ℃. The air blowing time (drying time) was set to 2 minutes.
The obtained transparent conductive film was supplied to the above evaluations (1) and (2). The results are shown in Table 1.
Examples 2 to 8 and comparative examples 1 to 2
A transparent conductive film was obtained in the same manner as in example 1, except that the initial thickness Ts of the coating layer (as a result, the amount x of the metal nanowires) and the thickness Tb of the coating layer at the time of starting air blowing in the air blowing process (at the time of starting air blowing) were set as shown in table 1. The obtained transparent conductive film was supplied to the above evaluations (1) and (2). The results are shown in Table 1.
Comparative example 3
A PET film (trade name "S100" manufactured by mitsubishi resin) was used as the base material. While the substrate was conveyed by a conveying roller, the transparent conductive layer-forming composition prepared in production example 1 was coated on the substrate by a bar coater (product name "bar coater No.6" manufactured by first science Co., ltd.) to form a coating layer having a thickness of 13 μm (i.e., every 1 m) 2 The amount x (g/m) of the metal nanowires 2 )＝0.012g/m 2 ). Then, the substrate on which the coating layer was formed was put into an oven at a temperature of 100 ℃ for 2 minutes to obtain a transparent conductive film. The obtained transparent conductive film was supplied to the above evaluations (1) and (2). The results are shown in Table 1.
TABLE 1
As can be seen from Table 1, according to the present invention, the specific value of the specific value is calculated by { conductivity y (1/Ω)/every 1m } 2 The amount x (g/m) of the metal nanowires 2 ) A (m) of the above "y=a×x (1)" obtained by the expression } 2 And/Ω·g) is a specific value or more, a transparent conductive film having high conductivity and low haze value adjusted in a balanced manner can be obtained. Such a transparent conductive film can be produced by a step of leaving the film. In addition, by optimizing the thickness of the coating layer at the start of blowing (optimizing the setting time) according to the initial thickness of the coating layer, the above effect becomes more remarkable.
Symbol description
10: substrate material
20: transparent conductive layer
100: a transparent conductive film.
Claims (4)
1. A transparent conductive film comprising a substrate and a transparent conductive layer disposed on one side of the substrate,
the transparent conductive layer comprises metal nanowires which,
the metal nanowires in the transparent conductive layer are in g/m 2 The relationship between the amount x in units and the electrical conductivity y in units of 1/Ω of the transparent conductive film is represented by the following formula (1):
y＝a×x (1)
in the formula (1), a is 0.77 or more.
2. The transparent conductive film according to claim 1, having a haze value of 20% or less.
3. The transparent conductive film according to claim 1 or 2, having a surface resistance value of 0.1 Ω/≡to 1000 Ω/≡.
4. The transparent conductive film according to any one of claims 1 to 3, wherein the metal nanowires in the transparent conductive layer are in g/m 2 The amount x in units is 0.005g/m 2 ～0.05g/m 2 。
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| Application Number | Priority Date | Filing Date | Title |
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| JP2021003466A JP2022108459A (en) | 2021-01-13 | 2021-01-13 | transparent conductive film |
| JP2021-003466 | 2021-01-13 | ||
| PCT/JP2022/000470 WO2022153958A1 (en) | 2021-01-13 | 2022-01-11 | Transparent conductive film |
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| CN116762145A true CN116762145A (en) | 2023-09-15 |
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| KR (1) | KR20230114757A (en) |
| CN (1) | CN116762145A (en) |
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| EP2816569B1 (en) | 2012-02-16 | 2017-04-19 | Okura Industrial Co., Ltd. | Method for manufacturing transparent conductive base material |
| KR20200130370A (en) * | 2018-03-09 | 2020-11-18 | 다이니폰 인사츠 가부시키가이샤 | Conductive film, sensor, touch panel and image display device |
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| JP2022108459A (en) | 2022-07-26 |
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