JP7419609B2 - transparent conductive film - Google Patents

Description

The present invention relates to transparent conductive films.

A transparent conductive film is known that includes a base material and a transparent conductive layer containing krypton in order on one side in the thickness direction (for example, see Patent Document 1 below).

In the transparent conductive film of Patent Document 1, the specific resistance of the transparent conductive layer is low.

Japanese Patent Application Publication No. 05-334924

When the transparent conductive layer is amorphous, depending on the use and purpose of the transparent conductive film, the amorphous transparent conductive layer can be converted into a crystalline transparent conductive layer by heating (amorphous transparent conductive layer). crystallization of the conductive layer). Since the transparent conductive layer is more fragile than the base material, there is a problem in that the transparent conductive layer is easily damaged by the above-mentioned heating.

The present inventors studied damage to an amorphous transparent conductive layer and obtained the following knowledge.

The amorphous transparent conductive layer containing krypton contracts in the plane direction by the heating described above. The surface direction is perpendicular to the thickness direction.

On the other hand, depending on the use and purpose of the transparent conductive film, there are cases where it is desired to provide the transparent conductive film with a base material that expands (expands) when heated.

In a transparent conductive film comprising the above-described base material that can be stretched by heating and the above-described amorphous transparent conductive layer containing krypton, the base material stretches while the non-crystalline conductive layer is stretched during crystallization of the amorphous transparent conductive layer. The crystalline transparent conductive layer contracts. Then, since the shrinkage direction of the amorphous transparent conductive layer is opposite to the stretching direction of the base material and a large stress is applied to the amorphous transparent conductive layer, the shrinkage direction of the amorphous transparent conductive layer is Damage becomes apparent.

The present inventors have found that damage to the amorphous transparent conductive layer can be suppressed by making the density of the amorphous transparent conductive layer exceed 7.27 g/cm ³ .

The present invention provides a transparent conductive film that is provided with a base material that can be stretched during crystallization of the amorphous transparent conductive layer, and that suppresses damage to the amorphous transparent conductive layer during crystallization of the amorphous transparent conductive layer. I will provide a.

The present invention (1) includes a base material and an amorphous transparent conductive layer in order toward one side in the thickness direction, and the base material has a first heat-shrinkable layer in a first direction perpendicular to the thickness direction. the second heat shrinkage rate HS2 of the base material in a second direction perpendicular to the thickness direction and the first direction, the second heat shrinkage rate HS2 being lower than the second heat shrinkage rate HS1; HS2 is 0.00% or less, the amorphous transparent conductive layer contains a rare gas with an atomic number higher than argon, and the density of the amorphous transparent conductive layer is 7.27 g/ ^cm3. Transparent conductive film.

Since the second heat shrinkage rate HS2 of the base material is 0.00% or less, the transparent conductive film includes a base material that can be stretched during crystallization of the amorphous transparent conductive layer.

On the other hand, since the density of the amorphous transparent conductive layer exceeds 7.27 g/cm ³ , damage to the amorphous transparent conductive layer during crystallization can be suppressed.

In the present invention (2), the transparent conductive film has a third heat shrinkage rate HS3 in the first direction, a fourth heat shrinkage rate HS4 lower than the third heat shrinkage rate HS3, and a fourth heat shrinkage rate HS4 in the second direction. 4 heat shrinkage rate HS4, and the fourth heat shrinkage rate HS4 is less than 0.04%.

In the present invention (3), a value obtained by subtracting the second heat shrinkage rate HS2 of the base material from the fourth heat shrinkage rate HS4 of the transparent conductive film (HS4-HS2) is 0.00% or more, The transparent conductive film described in (2) is included, the content of which is 0.10% or less.

The transparent conductive film of the present invention has a base material that can be stretched during crystallization of the amorphous transparent conductive layer, while suppressing damage to the amorphous transparent conductive layer during crystallization of the amorphous transparent conductive layer. Ru.

FIG. 1 is a plan view of an embodiment of a transparent conductive film of the present invention. 2 is a cross-sectional view of the transparent conductive film in FIG. 1. FIG.

1. Transparent conductive film 1
A transparent conductive film 1 that is an embodiment of the present invention will be described with reference to FIGS. 1 and 2. This transparent conductive film 1 extends in a direction perpendicular to the thickness direction. The direction orthogonal to the thickness direction includes a first direction and a second direction. The second direction is orthogonal to the first direction. In this embodiment, the transparent conductive film 1 extends in the first direction. The transparent conductive film 1 may be a roll (not shown) that is elongated in the first direction.

1.1 Layer Configuration of Transparent Conductive Film 1 The transparent conductive film 1 includes a base material 2 and an amorphous transparent conductive layer 3 in this order toward one side in the thickness direction. That is, in this transparent conductive film 1, the base material 2 and the amorphous transparent conductive layer 3 are arranged in order toward one side in the thickness direction. In this embodiment, the transparent conductive film 1 includes only the base material 2 and the amorphous transparent conductive layer 3.

1.2 Base material 2
In this embodiment, the base material 2 forms the other surface of the transparent conductive film 1 in the thickness direction. The base material 2 improves the mechanical strength of the transparent conductive film 1. The base material 2 extends in the first direction.

1.2.1 First heat shrinkage rate HS1 and second heat shrinkage rate HS2 of base material 2
The base material 2 has a first heat shrinkage rate HS1 in the first direction and a second heat shrinkage rate HS2 in the second direction. The second heat shrinkage rate HS2 is lower than the first heat shrinkage rate HS1. Note that the first direction in the first heat shrinkage rate HS1 is the direction that gives the base material 2 the highest heat shrinkage rate. In this embodiment, the first direction is the longitudinal direction of the base material 2. The second direction is orthogonal to the first direction. The second direction is the width direction of the base material 2.

The first thermal shrinkage rate HS1 is the degree of shrinkage in the first direction after heating the base material 2 at 160° C. for 1 hour. The first heat shrinkage rate HS1 is determined by the following formula.

First thermal contraction rate HS1 = [Length of the base material 2 in the first direction before heating - Length of the base material 2 in the first direction after heating] / [Length of the base material 2 in the first direction before heating] ]×100(%)

The second thermal shrinkage rate HS2 is the degree of shrinkage in the second direction after heating the base material 2 at 160° C. for 1 hour. The second heat shrinkage rate HS2 is determined by the following formula.

Second thermal contraction rate HS2 = [Length of the base material 2 in the second direction before heating - Length of the base material 2 in the second direction after heating] / [Length of the base material 2 in the second direction before heating] ]×100(%)

The first heat shrinkage rate HS1 is, for example, more than 0.00%, preferably 0.10% or more, more preferably 0.20% or more, and still more preferably 0.30% or more. That is, in this embodiment, the base material 2 contracts in the first direction when heated. The upper limit of the first heat shrinkage rate HS1 is not limited. The upper limit of the first heat shrinkage rate HS1 is, for example, 2.00%, or, for example, 1.00%.

On the other hand, the second heat shrinkage rate HS2 is 0.00% or less. That is, the base material 2 either expands in the second direction or does not change in size (does not expand or contract) when heated. Preferably, the substrate 2 stretches in the second direction when heated. Therefore, depending on the use and purpose, the transparent conductive film 1 can be suitably provided with the base material 2 that can be stretched in the second direction.

The second heat shrinkage rate HS2 is preferably -0.01% or less, more preferably -0.02% or less, still more preferably -0.03% or less, particularly preferably -0.04% or less. , most preferably -0.05% or less.

The second heat shrinkage rate HS2 is, for example, -0.20% or more, preferably -0.10% or more.

The first heat shrinkage rate HS1 and the second heat shrinkage rate HS2 of the base material 2 are determined by removing the amorphous transparent conductive layer 3 from the transparent conductive film 1 and heating the remaining base material 2. .

1.2.2 Layer Configuration of Base Material 2 In this embodiment, the base material 2 includes a base sheet 21 and a functional layer 20 in this order in the thickness direction. In this embodiment, the functional layer 20 is a multilayer. The functional layer 20 contacts one side and the other side of the base sheet 21 in the thickness direction. The functional layer 20 preferably includes an optical adjustment layer 22 and a hard coat layer 23. In this embodiment, the base material 2 preferably includes an optical adjustment layer 22, a base sheet 21, and a hard coat layer 23 in this order toward the other side in the thickness direction.

1.2.2.1 Base sheet 21
The base sheet 21 has flexibility. An example of the base sheet 21 is a resin film. The resin in the resin film is not limited. Examples of the resin include polyester resin, acrylic resin, olefin resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, polystyrene resin, and norbornene resin. Preferably, the resin is a polyester resin from the viewpoint of transparency and mechanical strength. Examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, and preferably PET.

The thickness of the base sheet 21 is preferably 1 μm or more, more preferably 10 μm or more, and still more preferably 30 μm or more. The thickness of the base sheet 21 is preferably 300 μm or less, more preferably 200 μm or less, still more preferably 150 μm or less, particularly preferably 100 μm or less. The ratio of the thickness of the base sheet 21 to the thickness of the base material 2 is, for example, 80% or more, preferably 95% or more, and is, for example, 100% or less, preferably 99% or less.

1.2.2.2 Optical adjustment layer 22
The optical adjustment layer 22 makes it difficult for the pattern shape of the amorphous transparent conductive layer 3 (or the crystalline transparent conductive layer 30 described later) to be visually recognized. The optical adjustment layer 22 is arranged on one surface of the base sheet 21 in the thickness direction. The optical adjustment layer 22 contacts one surface of the base sheet 21 in the thickness direction. The optical adjustment layer 22 is, for example, a cured product layer of a curable composition (first curable composition) containing a curable resin. Examples of the curable resin include acrylic resin, urethane resin, amide resin, silicone resin, epoxy resin, and melamine resin. In this embodiment, the cured material layer preferably does not contain particles. The refractive index of the optical adjustment layer 22 is, for example, 1.40 or more, preferably 1.55 or more, and is, for example, 1.80 or less, preferably 1.70 or less. The thickness of the optical adjustment layer 22 is, for example, 5 nm or more, preferably 10 nm or more, and is, for example, 200 nm or less, preferably 100 nm or less. The ratio of the thickness of the optical adjustment layer 22 to the thickness of the base material 2 is, for example, 0.01% or more, preferably 0.1% or more, and, for example, 2% or less, preferably 1% or less. be.

1.2.2.3 Hard coat layer 23
The hard coat layer 23 prevents scratches from being formed on one side of the amorphous transparent conductive layer 3 in the thickness direction when the transparent conductive film 1 is wound up to produce a roll body. Hard coat layer 23 is arranged on the other surface of base sheet 21 in the thickness direction. Hard coat layer 23 contacts the other surface of base sheet 21 in the thickness direction. The hard coat layer 23 is, for example, a cured product layer of a curable composition (second curable composition) containing particles and a curable resin. Examples of the particles include oxide particles, glass particles, and organic particles. Examples of the oxide particles include silica particles, alumina particles, titania particles, zirconia particles, calcium oxide particles, tin oxide particles, indium oxide particles, cadmium oxide particles, and antimony oxide particles. Examples of the material for the organic particles include polymethyl methacrylate particles, polystyrene particles, polyurethane particles, acrylic-styrene copolymer particles, benzoguanamine particles, melamine particles, and polycarbonate particles. Examples of the curable resin include curable resins contained in the first curable composition. The thickness of the hard coat layer 23 is, for example, 0.1 μm or more, preferably 0.5 μm or more, and is, for example, 10 μm or less, preferably 3 μm or less. The ratio of the thickness of the hard coat layer 23 to the thickness of the base material 2 is, for example, 0.1% or more, preferably 2% or more, and is, for example, 10% or less, preferably 5% or less.

The thickness of the functional layer 20 is, for example, 0.15 μm or more and, for example, 3.5 μm or less. The thickness of the functional layer 20 is the total thickness of the optical adjustment layer 22 and the hard coat layer 23. The ratio of the thickness of the functional layer 20 to the thickness of the base sheet 21 is, for example, 0.01 or more, preferably 0.02 or more, and is, for example, 0.10 or less, preferably 0.05 or less. be. The ratio of the thickness of the functional layer 20 to the thickness of the base material 2 is, for example, 1% or more, preferably 2% or more, and is, for example, 10% or less, preferably 5% or less.

1.2.3 Thickness of the base material 2 The thickness of the base material 2 is, for example, 5 μm or more, preferably 10 μm or more, more preferably 25 μm or more, and also, for example, 500 μm or less, preferably 200 μm or less, More preferably, it is 100 μm or less. The thickness of the base material 2 is the total thickness of the base material sheet 21, the optical adjustment layer 22, and the hard coat layer 23.

1.2.4 Physical Properties of Base Material 2 Other than Heat Shrinkage Rate The total light transmittance of base material 2 is, for example, 75% or more, preferably 80% or more, more preferably 85% or more, and even more preferably, It is 90% or more. The upper limit of the total light transmittance of the base material 2 is not limited. The upper limit of the total light transmittance of the base material 2 is, for example, 100%. The total light transmittance of the base material 2 is determined based on JIS K 7375-2008. The total light transmittance of the following members is determined based on the same method as above.

As the base material 2, a commercially available product can be used. Commercially available products include, for example, GF-50JBN (Mitsubishi Chemical Corporation).

1.3 Amorphous transparent conductive layer 3
In this embodiment, the amorphous transparent conductive layer 3 forms one surface of the transparent conductive film 1 in the thickness direction. The amorphous transparent conductive layer 3 is arranged on one surface of the base material 2 in the thickness direction. The amorphous transparent conductive layer 3 contacts one surface of the base material 2 in the thickness direction. In this embodiment, the amorphous transparent conductive layer 3 contacts one surface of the optical adjustment layer 22 (functional layer 20) in the thickness direction.

1.3.1 Heat Shrinkage Rate of Amorphous Transparent Conductive Layer 3 The heat shrinkage rate of the amorphous transparent conductive layer 3 in the second direction exceeds, for example, 0.00%. That is, the amorphous transparent conductive layer 3 contracts by heating, for example, in the second direction.

1.3.2 Density of the amorphous transparent conductive layer 3 The density of the amorphous transparent conductive layer 3 exceeds 7.27 g/cm ³ .

On the other hand, if the density of the amorphous transparent conductive layer 3 is 7.27 g/cm ³ or less, the amorphous transparent conductive layer 3 is not dense enough, and therefore, in the crystallization of the amorphous transparent conductive layer 3. , the amount of shrinkage of the transparent conductive layer 3 becomes large, and damage to the amorphous transparent conductive layer 3 cannot be suppressed. Specifically, the crystalline transparent conductive layer 30 is cracked.

On the other hand, in the present invention, since the density of the amorphous transparent conductive layer 3 exceeds 7.27 g/cm ³ , the amorphous transparent conductive layer 3 is sufficiently dense. In the crystallization, the amount of shrinkage of the transparent conductive layer 3 is reduced, and as a result, damage to the amorphous transparent conductive layer 3 is suppressed. Specifically, cracks in the crystalline transparent conductive layer 30 are suppressed.

The density of the amorphous transparent conductive layer 3 is preferably 7.28 g/cm ³ or more, more preferably 7.30 g/cm ³ or more, still more preferably 7.35 g/cm ³ or more, particularly preferably, It is preferably 7.38 g/cm ³ or more, most preferably 7.39 g/cm ³ or more, and even more preferably 7.40 g/cm ³ or more.

The upper limit of the density of the amorphous transparent conductive layer 3 is not limited. The upper limit of the density of the amorphous transparent conductive layer 3 is, for example, 8.00 g/cm ³ , more preferably 7.75 g/cm ³ .

The density of the amorphous transparent conductive layer 3 is adjusted, for example, by the method and conditions for forming the amorphous transparent conductive layer 3. When forming the amorphous transparent conductive layer 3 by sputtering, preferably the atmospheric pressure of the film forming gas is lowered and/or the film forming temperature is increased.

The density of the amorphous transparent conductive layer 3 is determined using the X-ray reflectance method.

1.3.3 Material, thickness, and other physical properties of the amorphous transparent conductive layer 3 Examples of the material of the amorphous transparent conductive layer 3 include metal oxides. The metal oxide contains at least one metal selected from the group consisting of In, Sn, Zn, Ga, Sb, Nb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. . Specifically, the material of the amorphous transparent conductive layer 3 is preferably indium zinc composite oxide (IZO), indium gallium zinc composite oxide (IGZO), indium gallium composite oxide (IGO), or indium tin. Examples include composite oxide (ITO) and antimony tin composite oxide (ATO), and preferably indium tin composite oxide (ITO) from the viewpoint of improving crack resistance.

The content of tin oxide (SnO ₂ ) in the indium tin composite oxide is, for example, 0.5% by mass or more, preferably 3% by mass or more, more preferably 6% by mass or more, and, for example, , less than 50% by weight, preferably 25% by weight or less, more preferably 15% by weight or less.

The amorphous transparent conductive layer 3 contains a rare gas having an atomic number higher than argon. In this embodiment, the amorphous transparent conductive layer 3 preferably contains a rare gas having an atomic number higher than argon, and does not contain argon.

In the first step described below, when the sputtering gas contains argon, a large amount of argon is taken into the amorphous transparent conductive layer 3. On the other hand, in the present embodiment in which the sputtering gas contains a rare gas having a higher atomic number than argon and does not contain argon, the amorphous transparent conductive layer 3 is suppressed from taking in a large amount of the sputtering gas. Therefore, the amorphous transparent conductive layer 3 becomes dense, and as a result, the density of the amorphous transparent conductive layer 3 becomes high.

Specifically, the amorphous transparent conductive layer 3 is a metal oxide containing a rare gas having an atomic number higher than argon. In other words, the amorphous transparent conductive layer 3 is a composition in which a rare gas having an atomic number higher than argon is mixed into a metal oxide.

Examples of the rare gas having an atomic number higher than argon include krypton, xenon, and radon. These can be used alone or in combination. Preferred examples of the rare gas having an atomic number larger than argon include krypton and xenon, and more preferably krypton (Kr) from the viewpoint of obtaining low cost and excellent electrical conductivity.

The method for identifying rare gases is not limited. For example, Rutherford Backscattering Spectrometry, secondary ion mass spectrometry, laser resonance ionization mass spectrometry, and/or X-ray fluorescence analysis shows that the atomic number of Noble gases are identified.

The content ratio of the rare gas having an atomic number higher than argon in the amorphous transparent conductive layer 3 is, for example, 0.0001 atom% or more, preferably 0.001 atom% or more, and, for example, 1.0 atom%. More preferably 0.7 atom% or less, still more preferably 0.5 atom% or less, even more preferably 0.3 atom% or less, particularly preferably 0.2 atom% or less, most preferably 0.15 atom% % or less. If the content of the rare gas having an atomic number higher than argon in the amorphous transparent conductive layer 3 is within the above range, the amorphous transparent conductive layer 3 can be made dense.

The lower limit of the content is a proportion corresponding to when the existence of a rare gas having an atomic number higher than argon is confirmed by a fluorescent X-ray analyzer, and is at least 0.0001 atomic % or more.

The thickness of the amorphous transparent conductive layer 3 is, for example, 15 nm or more, preferably 35 nm or more, more preferably 50 nm or more, even more preferably 75 nm or more, even more preferably 100 nm or more, particularly preferably 120 nm or more. It is. The thickness of the amorphous transparent conductive layer 3 is, for example, 500 nm or less, preferably 300 nm or less, and more preferably 200 nm or less.

The total light transmittance of the amorphous transparent conductive layer 3 is, for example, 75% or more, preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more. The upper limit of the total light transmittance of the amorphous transparent conductive layer 3 is not limited. The upper limit of the total light transmittance of the amorphous transparent conductive layer 3 is, for example, 100%.

The specific resistance of the amorphous transparent conductive layer 3 is, for example, 7.0×10 ⁻⁴ Ω·cm or less, preferably 6.0×10 ⁻⁴ Ω·cm or less, more preferably 5.5×10 ^-4 Ω・cm or less, more preferably 5.0×10 ⁻⁴ Ω・cm or less, and for example, 1×10 ⁻⁴ Ω・cm or more, preferably 2×10 ⁻⁴ Ω・cm More preferably, it is 3.0×10 ⁻⁴ Ω·cm or more. Specific resistance is measured by the four-terminal method.

1.4 Third heat shrinkage rate HS3 and fourth heat shrinkage rate HS4 of transparent conductive film 1
The transparent conductive film 1 has a third heat shrinkage rate HS3 in the first direction and a fourth heat shrinkage rate HS4 in the second direction. The fourth heat shrinkage rate HS4 is lower than the third heat shrinkage rate HS3.

In addition, in this embodiment, the 1st direction in 3rd heat shrinkage rate HS3 is the direction which gives the highest heat shrinkage rate to the transparent conductive film 1. In this embodiment, the first direction is the longitudinal direction of the transparent conductive film 1.

In this embodiment, the third thermal shrinkage rate HS3 is the degree of shrinkage in the first direction after the transparent conductive film 1 is heated at 160° C. for 1 hour. The third heat shrinkage rate HS3 is determined by the following formula.
Third thermal shrinkage rate HS3 = [Length of transparent conductive film 1 in the first direction before heating - Length of transparent conductive film 1 in the first direction after heating] / [Transparent in the first direction before heating Length of conductive film 1] x 100 (%)

In this embodiment, the fourth thermal shrinkage rate HS4 is the degree of shrinkage in the second direction after heating the transparent conductive film 1 at 160° C. for 1 hour. The fourth heat shrinkage rate HS4 is determined by the following formula.

Fourth heat shrinkage rate HS4 = [Length of transparent conductive film 1 in the second direction before heating - Length of transparent conductive film 1 in the second direction after heating] / [Transparent in second direction before heating Length of conductive film 1] x 100 (%)

The third heat shrinkage rate HS3 is, for example, more than 0.00%, preferably 0.10%, more preferably 0.15% or more, and still more preferably 0.20% or more. That is, in this embodiment, the transparent conductive film 1 contracts in the first direction when heated. The upper limit of the third heat shrinkage rate HS3 is not limited. The upper limit of the third heat shrinkage rate HS3 is, for example, 2.00%, or, for example, 1.00%.

The fourth heat shrinkage rate HS4 is, for example, 0.10% or less, preferably 0.05% or less, more preferably 0.04% or less, still more preferably 0.03% or less, particularly preferably 0. .00% or less, most preferably less than 0.00%, and even more preferably -0.01% or less. The fourth heat shrinkage rate HS4 is, for example, -0.20% or more, preferably -0.10% or more. If the fourth heat shrinkage rate HS4 is below the above-mentioned upper limit and above the above-mentioned lower limit, the difference (HS4-HS2) can be set to 0.00% or a small positive number, and as a result, the amorphous transparent conductive layer 3 Damage during crystallization can be effectively suppressed.

The fourth thermal contraction rate HS4 is adjusted, for example, by the method of forming the amorphous transparent conductive layer 3 and the conditions thereof. When forming the amorphous transparent conductive layer 3 by sputtering, preferably the atmospheric pressure of the film forming gas is lowered and/or the film forming temperature is increased.

The value obtained by subtracting the second heat shrinkage rate HS2 of the base material 2 from the fourth heat shrinkage rate HS4 of the transparent conductive film 1 (HS4-HS2) is, for example, 0.00% or more, preferably 0.00%. Excess, more preferably 0.01% or more, and, for example, 0.20% or less, preferably 0.10% or less, more preferably 0.07% or less, even more preferably 0.05%. % or less. If the above value (HS4-HS2) is above the above lower limit and below the upper limit, the amount of shrinkage of the amorphous transparent conductive layer 3 in the second direction during heating and the shrinkage amount of the base material 2 in the second direction during heating. The difference in the amount of elongation can be made small, and therefore, the stress applied to the amorphous transparent conductive layer 3 can be reduced, and damage to the amorphous transparent conductive layer 3 during crystallization can be effectively suppressed.

1.5 Thickness and other physical properties of the transparent conductive film 1 The thickness of the transparent conductive film 1 is, for example, 2 μm or more, preferably 20 μm or more, more preferably 30 μm or more, and, for example, 300 μm or less, Preferably it is 200 μm or less, more preferably 100 μm or less.

The total light transmittance of the transparent conductive film 1 is, for example, 75% or more, preferably 80% or more, and, for example, 100% or less.

1.6 Method for manufacturing transparent conductive film 1 In this method, each layer is arranged, for example, by a roll-to-roll method. The MD direction and TD direction in the roll-to-roll method correspond to the above-described first direction and second direction, respectively.

First, a long base material 2 is prepared. Specifically, each of the first curable composition and the second curable composition is applied to one side and the other side of the elongated base sheet 21, respectively. Thereafter, the curable resins in each of the first curable composition and the second curable composition are cured by heat or ultraviolet irradiation. As a result, the optical adjustment layer 22 and the hard coat layer 23 are formed on one side and the other side of the base sheet 21, respectively. In this way, the base material 2 is prepared. The base material 2 has the above-described first heat shrinkage rate HS1 and second heat shrinkage rate HS2.

Thereafter, an amorphous transparent conductive layer 3 is formed on one surface of the base material 2 in the thickness direction. For example, sputtering is carried out, preferably reactive sputtering.

A sputtering device is used for sputtering. The sputtering device includes a film forming roll. The film forming roll is equipped with a temperature adjustment device. The temperature adjustment device can adjust the temperature of the film forming roll. Since the film forming roll can contact the base material 2, the temperature of the base material 2 can be adjusted.

In sputtering (preferably reactive sputtering), the above-described metal oxide (sintered body thereof) is used as a target. The surface temperature of the film forming roll corresponds to the film forming temperature in sputtering. The film forming temperature is, for example, 0°C or higher, preferably 10°C or higher, more preferably 20°C or higher, even more preferably 30°C or higher, particularly preferably 40°C or higher, furthermore, 50°C or higher, and even more preferably is preferably 60°C or higher. If the film-forming temperature is equal to or higher than the above-mentioned lower limit, a (dense) amorphous transparent conductive layer 3 having a desired density can be formed.

The upper limit of the film forming temperature is, for example, 100°C, preferably 80°C. If the film-forming temperature is below the above-mentioned upper limit, the crystallization rate of the amorphous transparent conductive layer 3 can be increased.

Examples of the sputtering gas include rare gases having an atomic number higher than that of argon. Examples of the rare gas having an atomic number larger than argon include krypton, xenon, and radon, and preferably krypton (Kr). The sputtering gas preferably does not contain argon. The sputtering gas may be mixed with a reactive gas. Examples of the reactive gas include oxygen. The ratio of the amount of reactive gas introduced to the total amount of sputtering gas and reactive gas introduced is, for example, 0.1 flow% or more, preferably 0.5 flow% or more, and, for example, 5 flow% or less. , preferably 3% or less.

The atmospheric pressure within the sputtering apparatus is, for example, 1.0 Pa or less, preferably 0.8 Pa or less, more preferably 0.5 Pa or less, still more preferably 0.3 Pa or less, and, for example, 0.01 Pa or more. , preferably 0.05 Pa or more. If the atmospheric pressure in the sputtering device is below the above-mentioned upper limit, it is possible to form the amorphous transparent conductive layer 3 having a desired density (fine).

As a result, a transparent conductive film 1 including a base material 2 and an amorphous transparent conductive layer 3 is manufactured.

Thereafter, depending on the use and purpose, the amorphous transparent conductive layer 3 can be converted to a crystalline state to form a crystalline transparent conductive layer 30, as indicated by the parenthetical symbols in FIG.

In order to convert the amorphous transparent conductive layer 3 into a crystalline state, the transparent conductive film 1 provided with the amorphous transparent conductive layer 3 is heated.

The heating temperature is, for example, 80°C or higher, preferably 110°C or higher, more preferably 130°C or higher, especially preferably 150°C or higher, and, for example, 200°C or lower, preferably, The temperature is 180°C or lower, more preferably 175°C or lower, even more preferably 170°C or lower. The heating time is, for example, 1 minute or more, preferably 3 minutes or more, more preferably 5 minutes or more, and for example, 5 hours or less, preferably 3 hours or less, more preferably 2 hours or less. be. Heating is performed, for example, under atmospheric conditions.

The crystallinity of the transparent conductive layer can be determined, for example, by immersing the transparent conductive layer in hydrochloric acid (20° C., concentration 5% by mass) for 15 minutes, followed by washing with water and drying, and then dipping the transparent conductive layer in a 15 mm distance from one side of the transparent conductive layer. Judgment is made by measuring the resistance between the terminals. In the amorphous transparent conductive layer 3 after immersion, water washing, and drying, if the resistance between terminals (resistance between two terminals) between 15 mm is 10 kΩ or less, the transparent conductive layer is crystalline (that is, the crystalline transparent conductive layer 30), and on the other hand, when the resistance exceeds 10 kΩ, the transparent conductive layer 3 is amorphous (that is, an amorphous transparent conductive layer 3).

The density of the crystalline transparent conductive layer 30 is, for example, 6.50 g/cm ³ or more, preferably 6.60 g/cm ³ or more, more preferably 6.70 g/cm ³ or more, more preferably 6.80 g /cm ³ or more, preferably 6.90g/cm ³ or more, preferably 7.00g/cm ³ or more, preferably 7.10g/cm ³ or more, preferably 7.20g/cm ³ or more. , and, for example, 8.0 g/cm ³ or less. If the density of the crystalline transparent conductive layer 30 is at least the above-described lower limit, damage to the dense crystalline transparent conductive layer 30 is suppressed.

The total light transmittance of the crystalline transparent conductive layer 30 is, for example, 75% or more, preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more. The upper limit of the total light transmittance of the crystalline transparent conductive layer 30 is not limited. The upper limit of the total light transmittance of the crystalline transparent conductive layer 30 is, for example, 100%.

The specific resistance of the crystalline transparent conductive layer 30 is, for example, 5.0×10 ⁻⁴ Ω·cm or less, preferably 2.5×10 ⁻⁴ Ω·cm or less, more preferably 2.4×10 ⁻⁴ Ω・cm or less, more preferably 2.0×10 ⁻⁴ Ω・cm or less, even more preferably 1.8×10 −4 Ω・cm or less, and, for example, 0.1×10 ^-4 Ω·cm or more, preferably 0.5×10 ⁻⁴ Ω·cm or more, more preferably 1.0×10 ⁻⁴ Ω·cm or more. Specific resistance is measured by the four-terminal method.

1.7 Applications of the transparent conductive film 1 The transparent conductive film 1 is used, for example, in articles. Examples of the article include optical articles. Specifically, examples of the article include a touch sensor, an electromagnetic shield, a light control element, a photoelectric conversion element, a heat ray control member, a light-transmitting antenna member, a light-transmitting heater member, an image display device, and lighting.

2. Effects of one embodiment In this transparent conductive film 1, the second heat shrinkage rate HS2 of the base material 2 is 0.00% or less. In crystallization, a stretchable substrate 2 is provided. Therefore, the transparent conductive film 1 can be suitably used in fields where the base material 2 is allowed to stretch.

On the other hand, since the density of the amorphous transparent conductive layer 3 exceeds 7.27 g/cm ³ , damage to the amorphous transparent conductive layer 3 during crystallization can be suppressed.

Further, if the fourth heat shrinkage rate HS4 of the transparent conductive film 1 is less than 0.00%, damage to the amorphous transparent conductive layer 3 during crystallization can be effectively suppressed.

Furthermore, the value obtained by subtracting the second heat shrinkage rate HS2 of the base material 2 from the fourth heat shrinkage rate HS4 of the transparent conductive film 1 (HS4-HS2) may be 0.00% or more and 0.10% or less. For example, the difference between the amount of shrinkage of the transparent conductive film 1 in the second direction during heating during crystallization of the amorphous transparent conductive layer 3 and the amount of shrinkage of the base material 2 in the second direction during heating can be reduced.
Therefore, the stress applied to the amorphous transparent conductive layer 3 can be reduced, and damage to the amorphous transparent conductive layer 3 during crystallization can be effectively suppressed.

3. Modification Examples In each modification example below, the same reference numerals are given to the same members and steps as in the above-described embodiment, and detailed explanation thereof will be omitted. Moreover, each modification can produce the same effects as the one embodiment except as otherwise specified. Furthermore, one embodiment and the modified examples can be combined as appropriate.

When the transparent conductive film 1 is not unrolled from the roll body and the MD direction and the TD direction are unknown, the first direction is the direction in which the thermal shrinkage rate is maximized by heating. The second direction is perpendicular to the first direction and the thickness direction. As a result, the first direction and the second direction are specified, and as a result, the third heat shrinkage rate HS3 and the fourth heat shrinkage rate HS4 of the transparent conductive film 1 and the first heat shrinkage rate HS1 and the fourth heat shrinkage rate HS4 of the base material 2 are determined. 2 The heat shrinkage rate HS2 is determined.

In a modified example, although not shown, the functional layer 20 is arranged on one side or the other side of the base sheet 21 in the thickness direction. The functional layer 20 may be either a hard coat layer or an optical adjustment layer. That is, the single or plural functional layers 20 are arranged on one side and/or the other side of the base sheet 21 in the thickness direction.

EXAMPLES Below, the present invention will be explained in more detail with reference to Examples. Note that the present invention is not limited to the examples at all. In addition, the specific numerical values of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description are the corresponding blending ratios ( Content percentage), physical property values, parameters, etc. can be replaced with the upper limit (value defined as "less than" or "less than") or lower limit (value defined as "more than" or "exceeding"). can.

<Example 1>
A long base material 2 was prepared. Specifically, a base sheet 21 made of PET, an optical adjustment layer 22 disposed on one surface of the base material 2 in the thickness direction, and a hard coat layer 23 disposed on the other surface of the base material 2 in the thickness direction. A roll body of base material 2 (manufactured by Mitsubishi Chemical Corporation, product name: GF-50JBN) having a thickness of 52 μm was prepared.

An amorphous transparent conductive layer 3 having a thickness of 145 nm was formed on one side of the base material 2 by a reactive sputtering method. In the reactive sputtering method, the roll body described above is set in a DC magnetron sputtering device, and while the base material 2 is fed out from the roll body in the MD direction, an amorphous transparent conductive layer 3 is continuously formed on one side of the base material 2. The transparent conductive film 1 was formed into a roll body.

The sputtering conditions are as follows. A sintered body of indium oxide and tin oxide was used as a target. The tin oxide concentration in the sintered body was 10% by mass. A voltage was applied to the target using a DC power supply. The horizontal magnetic field strength above the target was 90 mT. The film forming temperature was 30°C. The film forming temperature is the surface temperature of the film forming roll, and is the same as the temperature of the base material 2. Further, the film forming chamber was evacuated until the ultimate vacuum degree within the film forming chamber in the DC magnetron sputtering apparatus reached 0.9×10 ⁻⁴ Pa, and the base material 2 was degassed. Thereafter, Kr as a sputtering gas and oxygen as a reactive gas were introduced into the film forming chamber, and the atmospheric pressure in the film forming chamber was set to 0.2 Pa. The ratio of the amount of oxygen introduced to the total amount of Kr and oxygen introduced into the film forming chamber was about 3.1%.

<Example 2 to Example 3 and Comparative Example 1 to Comparative Example 2>
Transparent conductive film 1 was produced in the same manner as in Example 1. However, the atmospheric pressure in the film forming chamber or the film forming temperature was changed as shown in Table 1.

<Evaluation>
The following items were evaluated for the transparent conductive film 1 of each Example and each Comparative Example.

(1) Third heat shrinkage rate HS3 and fourth heat shrinkage rate HS4 of transparent conductive film 1
The transparent conductive film 1 immediately after production was cut into a size of 10 cm x 10 cm (see virtual line in FIG. 1). The dimensions of the transparent conductive film 1 in the first direction (MD direction) and second direction (TD direction) were measured using a plane biaxial device (manufactured by Mitutoyo, QV ACCEL606-PRO).

Thereafter, the transparent conductive film 1 was heated in a hot air oven at 160° C. for 1 hour, and then left to stand until the temperature returned to room temperature. This converted the amorphous transparent conductive layer 3 to crystalline. Thereafter, the dimensions of the transparent conductive film 1 in the first direction (MD direction) and the second direction (TD direction) were measured. Then, the third heat shrinkage rate HS3 and the fourth heat shrinkage rate HS4 of the transparent conductive film 1 were determined. The results are listed in Table 1.

(2) First heat shrinkage rate HS1 and second heat shrinkage rate HS2 of base material 2
The transparent conductive film 1 immediately after production was cut into a size of 10 cm x 10 cm. Thereafter, the amorphous transparent conductive layer 3 was removed from the transparent conductive film 1. Specifically, the transparent conductive film 1 was immersed in hydrochloric acid (20° C., concentration 5% by mass) for 30 minutes, then washed with water and dried. In this way, a base material 2 was obtained.

Thereafter, the dimensions of the base material 2 in the first direction (MD direction) and second direction (TD direction) were measured using a plane biaxial device (manufactured by Mitutoyo, QV ACCEL606-PRO). Thereafter, the base material 2 was heated in a hot air oven at 160° C. for 1 hour, and then left to stand until the temperature returned to room temperature. This converted the amorphous transparent conductive layer 3 to crystalline. Thereafter, the dimensions of the base material 2 in the first direction (MD direction) and the second direction (TD direction) were measured. Then, the first heat shrinkage rate HS1 and the second heat shrinkage rate HS2 of the base material 2 were determined. The results are listed in Table 1.

(3) Density of amorphous transparent conductive layer 3 The density of the amorphous transparent conductive layer 3 was determined using an X-ray reflectance method. Specifically, using a horizontal X-ray diffraction device (product name "SmartLab", manufactured by Rigaku Co., Ltd.), "XRR-vibration analysis/fitting" of analysis software (software name "SmartLab Studio II") was used, Fitting of the X-ray reflectance curve obtained in the measurement and the theoretical profile was performed in the range of 2θ=0.5 to 1.0 deg. In the fitting, the quasi-Newton method and residual type |Δ(LogI)|(I: X-ray intensity) were used.

<Measurement conditions>
・Parallel beam optical arrangement ・Light source: CuKα ray (wavelength: 1.54059 Å)
・Incidence side slit system: Solar slit OPEN
・Incidence slit: 0.050mm
・Light receiving side slit system: Solar slit 5.0deg
・Light receiving slit: 0.050mm
・Detector: Multidimensional pixel detector Hypix-3000
・Output: 45kV, 200mA
・Measurement speed: 0.1°/min ・Measurement range: 0° to 1.5°
・Scan axis: 2θ/ω
・Step interval: 0.008°
The results are listed in Table 1.

(4) Evaluation of crack resistance (i) A first heating test and (ii) a second heating test were conducted.

(i) First heating test The transparent conductive film 1 was rolled out from the roll body immediately after production, and cut into a size of 50 cm x 5 cm. Both short sides of the cut transparent conductive film 1 were fixed with heat-resistant tape, and heated in a hot air oven at 160° C. for 1 hour in the atmosphere.

Thereafter, the transparent conductive film 1 was cut into 10 pieces. The size of each transparent conductive film 1 is 5 cm x 5 cm. The number of transparent conductive films 1 in which cracks were observed among the ten transparent conductive films 1 was counted. Cracks were observed under a microscope.

(ii) Second heating test The transparent conductive film 1 immediately after forming the amorphous transparent conductive layer 3 and before being wound into a roll body was continuously conveyed under vacuum without being wound. At the same time, it was brought into contact with a heating roll (temperature: 160°C) and heated for about 5 minutes. Thereafter, the transparent conductive film 1 was cut into a size of 50 cm x 5 cm.

Thereafter, the transparent conductive film 1 was cut into 10 pieces. The size of each transparent conductive film 1 is 5 cm x 5 cm. The number of transparent conductive films 1 in which cracks were observed among the ten transparent conductive films 1 was counted. Cracks were observed under a microscope.

Then, the crack resistance was evaluated as follows.

Excellent: In both (i) the first heating test and (ii) the second heating test, cracks were confirmed in the crystalline transparent conductive layer 30 of 5 or less of the 10 transparent conductive films 1. .
Good: (i) In the first heating test, cracks were observed in the crystalline transparent conductive layer 30 of 5 or less of the 10 transparent conductive films 1. On the other hand, in (ii) the second heating test, cracks were confirmed in the crystalline transparent conductive layer 30 of 6 or more of the 10 transparent conductive films 1.
Defective: In both (i) the first heating test and (ii) the second heating test, cracks were confirmed in the crystalline transparent conductive layer 30 of 6 or more of the 10 transparent conductive films 1.

The results are listed in Table 1.

(5) [Confirmation of Kr in amorphous transparent conductive layer 3]
It was confirmed in the following manner that the amorphous transparent conductive layer 3 in each of Examples 1 to 3 and Comparative Examples 1 to 2 contained Kr.

First, using a scanning X-ray fluorescence analyzer (product name "ZSX Primus IV", manufactured by Rigaku Corporation), X-ray fluorescence analysis measurements were repeated five times under the following measurement conditions, and the average value of each scanning angle was calculated. and created an X-ray spectrum. In the created X-ray spectrum, it was confirmed that a peak appeared near the scanning angle of 28.2°.

<Measurement conditions>
Spectrum; Kr-KA
Measurement diameter: 30mm
Atmosphere: Vacuum Target: Rh
Tube voltage: 50kV
Tube current: 60mA
Primary filter: Ni40
Scanning angle (deg): 27.0 to 29.5
Step (deg): 0.020
Speed (deg/min): 0.75
Attenuator: 1/1
Slit: S2
Spectroscopic crystal: LiF (200)
Detector: SC
PHA: 100-300

(6) [Confirmation of Ar in amorphous transparent conductive layer 3]
It was confirmed by Rutherford backscattering spectroscopy (RBS) that the amorphous transparent conductive layers 3 in each of Examples 1 to 3 and Comparative Examples 1 to 2 did not contain Ar.

Specifically, the four elements of detection were In+Sn (with Rutherford backscattering spectroscopy, it was difficult to measure In and Sn separately, so the evaluation was performed as a sum of the two elements), O, and Ar. The presence of Ar in the transparent conductive layer was confirmed. The equipment used and measurement conditions are as follows.

<Equipment used>
Pelletron 3SDH (manufactured by National Electrostatics Corporation)

<Measurement conditions>
Incident ion: 4He++
Incident energy: 2300keV
Incident angle: 0deg
Scattering angle: 160deg
Sample current: 6nA
Beam diameter: 2mmφ
In-plane rotation: None Irradiation dose: 75μC

Note that although the above invention has been provided as an exemplary embodiment of the present invention, this is merely an example and should not be interpreted in a limiting manner. Variations of the invention that are obvious to those skilled in the art are within the scope of the following claims.

Transparent conductive films are used in optical articles.

1 Transparent conductive film 2 Base material 3 Amorphous transparent conductive layer HS1 First heat shrinkage rate of the base material in the first direction HS2 First heat shrinkage rate of the base material in the second direction HS3 Transparent conductive film in the first direction The first heat shrinkage rate HS4 of the transparent conductive film in the second direction

Claims (3)

A base material and an amorphous transparent conductive layer are provided in order toward one side in the thickness direction,
The base material has a second heat shrinkage rate HS2 lower than a first heat shrinkage rate HS1 in a first direction perpendicular to the thickness direction, and the second heat shrinkage rate HS2 in a second direction perpendicular to the thickness direction and the first direction. 2 has a heat shrinkage rate HS2,
The second heat shrinkage rate HS2 of the base material is 0.00% or less,
The amorphous transparent conductive layer contains a rare gas having an atomic number higher than argon,
The transparent conductive film has a density of the amorphous transparent conductive layer exceeding 7.27 g/cm ³ . The transparent conductive film has a third heat shrinkage rate HS3 in the first direction and a fourth heat shrinkage rate HS4 lower than the third heat shrinkage rate HS3, and a fourth heat shrinkage rate HS4 in the second direction. have,
The transparent conductive film according to claim 1, wherein the fourth heat shrinkage rate HS4 is less than 0.04%.
The value obtained by subtracting the second heat shrinkage rate HS2 of the base material from the fourth heat shrinkage rate HS4 of the transparent conductive film (HS4-HS2) is 0.00% or more and 0.10% or less. , The transparent conductive film according to claim 2.