JP6823480B2 - Transparent conductive film - Google Patents

Description

The present invention relates to a transparent conductive film.

Conventionally, a transparent conductive laminate in which an anti-blocking layer, a color difference adjusting layer, and a transparent conductive layer are laminated in this order on a transparent polymer base material has been proposed (see, for example, Patent Document 1).

In the transparent conductive laminate described in Patent Document 1, the transparent conductive layer is formed in a pattern having a predetermined shape.

In Patent Document 1, the anti-blocking layer ensures the anti-blocking property, and the color difference adjusting layer suppresses the difference in the visibility of the pattern to ensure the optical characteristics.

Japanese Unexamined Patent Publication No. 2012-666477

However, in Patent Document 1, it is necessary to provide two layers, an anti-blocking layer and a color difference adjusting layer, which causes a problem that the layer structure becomes complicated.

Further, in recent years, further improvement in both anti-blocking property and optical property has been desired.

An object of the present invention is to provide a transparent conductive film having a simple layer structure and excellent in both blocking resistance and optical properties.

The present invention (1) includes a transparent base material, transparent conductive layers arranged on one side or both sides of the transparent base material, and an intermediate layer interposed between the transparent base material and the transparent conductive layer. The intermediate layer contains first inorganic particles having a median diameter of 5 nm or more and less than 45 nm, second inorganic particles having a median diameter of 45 nm or more and less than 120 nm, and a resin, and the first inorganic particles of the first inorganic particles. The content ratio to 100 parts by mass of the resin is 65 parts by mass or more and 235 parts by mass or less, and the content ratio of the second inorganic particles to 100 parts by mass of the resin is 5 parts by mass or more and 80 parts by mass or less. , Includes transparent conductive film.

The transparent conductivity according to (1), wherein the content ratio of the first inorganic particles and the second inorganic particles to 100 parts by mass of the resin is 85 parts by mass or more and 260 parts by mass or less. Includes sex film.

The present invention (3) includes the transparent conductive film according to (1) or (2), wherein the intermediate layer has a thickness of less than 500 nm.

The present invention (4) includes the transparent conductive film according to any one of (1) to (3), wherein the intermediate layer is a blocking-resistant optical adjustment layer.

The present invention (5) includes the transparent conductive film according to any one of (1) to (4), wherein both the first inorganic particles and the second inorganic particles are zirconia particles.

The present invention (6) includes the transparent conductive film according to any one of (1) to (5), further comprising a hard coat layer interposed between the transparent base material and the intermediate layer.

According to (6), the present invention (7) has a plurality of protrusions on the surface of the hard coat layer, and the maximum protrusion length of the protrusions per 1 cm ^{2 of the} hard coat layer is 200 nm or less. Includes a transparent conductive film.

The transparent conductive film of the present invention has a simple layer structure and is excellent in both blocking resistance and optical properties.

FIG. 1 shows a cross-sectional view of an embodiment of the transparent conductive film of the present invention (a mode in which a hard coat layer, an intermediate layer, and a transparent conductive layer are provided on a transparent base material). FIG. 2 shows a modified example of the transparent conductive film shown in FIG. 1 (a mode in which a hard coat layer, an intermediate layer, and a transparent conductive layer are provided above and below the transparent base material). FIG. 3 shows a modified example of the transparent conductive film shown in FIG. 1 (a mode in which an intermediate layer and a transparent conductive layer are provided on a transparent base material). FIG. 4 shows a modified example of the transparent conductive film shown in FIG. 1 (a mode in which an intermediate layer and a transparent conductive layer are provided above and below the transparent base material).

An embodiment of the transparent conductive film of the present invention will be described with reference to FIG.

1. 1. Transparent Conductive Film As shown in FIG. 1, the transparent conductive film 1 has a film shape (including a sheet shape) having a predetermined thickness, extends in a predetermined direction (plane direction) orthogonal to the thickness direction, and is flat. It has a flat upper surface and a flat lower surface (two main surfaces).

The transparent conductive film 1 includes a transparent base material 2, a transparent conductive layer 5 arranged on one side of the transparent base material 2, and a hard coat layer 3 and an intermediate layer interposed between the transparent base material 2 and the transparent conductive layer 5. 4 and. Specifically, the transparent conductive film 1 includes a transparent base material 2, a hard coat layer 3, an intermediate layer 4, and a transparent conductive layer 5 in this order. That is, the transparent conductive film 1 is formed on the transparent base material 2, the hard coat layer 3 provided on the transparent base material 2, the intermediate layer 4 provided on the hard coat layer 3, and the intermediate layer 4. It is provided with a transparent conductive layer 5 to be provided. Preferably, the transparent conductive film 1 is composed of only the transparent base material 2, the hard coat layer 3, the intermediate layer 4, and the transparent conductive layer 5. Hereinafter, each layer will be described in detail.

2. 2. Transparent base material The transparent base material 2 is a lower layer of the transparent conductive film 1 and is a support layer (support material) for ensuring the mechanical strength of the transparent conductive film 1. Further, the transparent base material 2 has a film shape extending in the surface direction, and has a flat flat surface and a flat lower surface (two main surfaces).

The transparent base material 2 is made of a polymer film. The polymer film has transparency. Examples of the material of the polymer film include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and (meth) acrylic resins (acrylic resin and / or methacrylic resin) such as polymethacrylate, for example, polyethylene. Olefin resins such as polypropylene and cycloolefin polymers (COPs), such as polycarbonate resins, such as polyether sulfone resins, such as polyarylate resins, such as melamine resins, such as polyamide resins, such as polyimide resins, such as cellulose resins. For example, polystyrene resin, for example, norbornene resin and the like can be mentioned. These polymer films can be used alone or in combination of two or more. From the viewpoint of transparency, mechanical properties and the like, an olefin resin is preferable, and COP is more preferable.

The thickness of the transparent substrate 2 is, for example, 2 μm or more, preferably 20 μm or more, and for example, 300 μm or less, preferably 200 μm or less.

3. 3. Hard coat layer The hard coat layer 3 is a layer for enhancing the scratch resistance of the transparent conductive film 1, and is a layer interposed between the transparent base material 2 and the intermediate layer 4 described below. The hard coat layer 3 has a film shape extending in the plane direction, and has a substantially flat upper surface and a flat lower surface (two main surfaces).

The hard coat layer 3 has a film shape (including a sheet shape) and is in direct contact with the entire upper surface of the transparent base material 2.

The hard coat layer 3 is made of, for example, a known resin composition. Further, the resin composition may also contain particles (particles containing organic particles and inorganic particles) described later in an appropriate ratio.

Further, the hard coat layer 3 may have a plurality of protrusions (not shown) on the upper surface thereof, and the maximum protrusion length of such protrusions per 1 cm ² of the hard coat layer is, for example, 200 nm or less. It is preferably 100 nm or less, more preferably 10 nm or less, and for example, 1 nm or more. When the maximum protrusion length of the protrusion is equal to or less than the above upper limit, the upper surface of the hard coat layer 3 can be substantially smoothed. Therefore, haze can be suppressed.

The roughness (surface roughness) of the upper surface of the hard coat layer 3 is, for example, 10 nm or less, preferably 5 nm or less, and for example, 0.1 nm or more. A method for measuring the surface roughness of the hard coat layer 3 will be described in a later example.

The thickness of the hard coat layer 3 is, for example, 0.1 μm or more, preferably 0.5 μm or more, and for example, 10 μm or less, preferably 5 μm or less.

4. Intermediate layer The intermediate layer 4 is provided on the upper surface of the hard coat layer 3. The intermediate layer 4 is a layer interposed between the hard coat layer 3 and the transparent conductive layer 5 described below. Further, the intermediate layer 4 is a functional layer that imparts functionality according to the purpose. Specifically, the intermediate layer 4 imparts blocking resistance to the transparent conductive film 1, and after the transparent conductive layer 5 is formed into a pattern in a later step, there is a difference between the non-patterned portion and the patterned portion. It is a blocking-resistant optical adjustment layer that adjusts the optical properties of the transparent conductive layer 5 so as not to be recognized (that is, to suppress the visibility of the pattern).

The intermediate layer 4 is in direct contact with the entire upper surface of the hard coat layer 3. The intermediate layer 4 has a film shape extending in the plane direction. The intermediate layer 4 has an uneven upper surface (not shown in FIG. 1) due to the second inorganic particles described later, and a substantially flat lower surface (two) corresponding to the upper surface of the hard coat layer 3. Main surface).

The intermediate layer 4 contains the first inorganic particles, the second inorganic particles, and the resin. Specifically, the intermediate layer 4 is composed of a particle resin composition containing the first inorganic particles, the second inorganic particles, and a resin. That is, the material of the intermediate layer 4 is a particle resin composition.

The particle resin composition preferably contains the first inorganic particles, the second inorganic particles, and the resin. More preferably, the particle resin composition comprises only the first inorganic particles, the second inorganic particles, and the resin.

4-1. First Inorganic Particles The first inorganic particles are small particles having a relatively small median diameter among the inorganic particles. The first inorganic particles are optical particles that improve the optical properties of the transparent conductive film 1, specifically, by adjusting the refractive index of the intermediate layer 4 to a desired range, the pattern visibility of the transparent conductive layer 5 is suppressed. Optical particles.

Examples of the first inorganic particles include silicon oxide (silica) particles, for example, metal oxide particles composed of zirconium oxide (zirconia), titanium oxide (titania), zinc oxide, tin oxide and the like, and carbonates such as calcium carbonate. Inorganic particles such as salt particles can be mentioned. As the first inorganic particle, a single type can be used alone, or a plurality of types can be used in combination. Examples of the particles include metal oxide particles, more preferably silicon oxide (silica) particles, zirconium oxide (zirconia), and even more preferably zirconium oxide particles (zirconia particles). Zirconium oxide particles are suitable as the first inorganic particles because the refractive index of the film can be easily changed depending on the amount of the zirconium oxide particles added.

The first inorganic particles have a median diameter of 5 nm or more and less than 45 nm.

The first inorganic particles preferably have a median diameter of 6 nm or more, more preferably 9 nm or more, still more preferably 10 nm or more, particularly preferably 12 nm or more, most preferably 15 nm or more, and preferably. It has a median diameter of 40 nm or less, more preferably less than 40 nm, and particularly preferably 35 nm or less.

If the median diameter of the first inorganic particles exceeds the above-mentioned lower limit, the adhesion of the intermediate layer 4 to the transparent conductive layer 5 can be improved. When the median diameter of the first inorganic particles is less than the above-mentioned upper limit, the transparent conductive film 1 can have an excellent appearance.

The first inorganic particles are monodisperse particles having a standard deviation of particle size distribution within 10%. In that case, the first inorganic particles have one median diameter.

On the other hand, the first inorganic particles can also have a bimodal particle size distribution. In that case, the first inorganic particles have two median diameters. In this case, the first inorganic particle contains, of the two median diameters, a small diameter particle having a small median diameter and a large diameter particle having a large median diameter. The content ratio of the small-diameter particles is, for example, 10 parts by mass or more, preferably 20 parts by mass or more, and for example, less than 50 parts by mass, preferably 20 parts by mass or less with respect to 100 parts by mass of the large-diameter particles. Is. The content ratio of the small-diameter particles is 10 parts by mass or more, preferably 20 parts by mass or more, more preferably 25 parts by mass or more, and for example, less than 50 parts by mass, with respect to 100 parts by mass of the resin. Preferably, it is 30 parts by mass or less. The content ratio of the large-diameter particles is, for example, 100 parts by mass or more, preferably 300 parts by mass or more, more preferably 500 parts by mass or more, and for example, 1000 parts by mass with respect to 100 parts by mass of the small-diameter particles. Hereinafter, it is preferably 750 parts by mass or less, and more preferably 500 parts by mass or less. The content ratio of the large-diameter particles is 50 parts by mass or more, preferably 100 parts by mass or more, more preferably 130 parts by mass or more, and for example, 200 parts by mass or less with respect to 100 parts by mass of the resin. It is preferably 175 parts by mass or less, and more preferably 130 parts by mass or less.

The content ratio of the first inorganic particles is 65 parts by mass or more, preferably 70 parts by mass or more, more preferably 75 parts by mass or more, still more preferably 80 parts by mass or more, based on 100 parts by mass of the resin. Particularly preferably, it is 90 parts by mass or more, and most preferably 100 parts by mass or more.

The content ratio of the first inorganic particles is 235 parts by mass or less, preferably 230 parts by mass or less, more preferably 200 parts by mass or less, still more preferably 175 parts by mass or less, based on 100 parts by mass of the resin. Particularly preferably, it is 150 parts by mass or less.

Further, the content ratio of the first inorganic particles is, for example, 30% by mass or more, preferably 35% by mass or more, more preferably 40% by mass, based on the intermediate layer 4 (that is, the solid content of the particle resin composition). % Or more, more preferably 45% by mass or more, and for example, 66% by mass or less, preferably 63% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass or less. ..

If the content ratio of the first inorganic particles is not less than the above lower limit, or if the content ratio of the first inorganic particles is not more than the above upper limit, the refractive index of the intermediate layer 4 can be set in a desired range. .. Therefore, the reflectance difference (ΔR, which will be described later) between the pattern formed from the transparent conductive layer 5 and the non-pattern cannot be reduced, and the pattern visibility of the transparent conductive layer 5 can be suppressed.

4-2. Second Inorganic Particles The second inorganic particles are large particles having a larger median diameter than the first inorganic particles among the inorganic particles. The second inorganic particles are blocking-resistant particles that impart excellent blocking resistance to the transparent conductive film 1.

Examples of the second inorganic particles include the inorganic particles exemplified in the first inorganic particles, preferably inorganic particles of the same type as the first inorganic particles, and more preferably zirconium oxide particles.

If the first inorganic particles and the second inorganic particles are the same type of inorganic particles (preferably zirconium particles), the composition of the intermediate layer 4 can be simplified while simplifying the manufacturing process of the transparent conductive film 1. it can.

The second inorganic particles have a median diameter of 45 nm or more and less than 120 nm. The second inorganic particles are preferably 55 nm or more, more preferably 60 nm or more, still more preferably 65 nm or more, and preferably 110 nm or less, more preferably 100 nm or less, still more preferably 80 nm or less. Has a median diameter.

When the median diameter of the second inorganic particles exceeds the above-mentioned lower limit, the transparent conductive film 1 can have excellent blocking resistance. When the median diameter of the second inorganic particles is less than the above-mentioned upper limit, the transparent conductive film 1 can have an excellent appearance.

It should be noted that preferably, the second inorganic particles are monodisperse particles having a standard deviation of the particle size distribution within 10%.

The content ratio of the second inorganic particles is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, more preferably more than 10 parts by mass, and even more preferably 12 parts by mass or more, based on 100 parts by mass of the resin. Particularly preferably, it is 15 parts by mass or more, and most preferably 20 parts by mass or more.

The content ratio of the second inorganic particles is, for example, 80 parts by mass or less, preferably less than 80 parts by mass, preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and further, with respect to 100 parts by mass of the resin. Preferably, it is 25 parts by mass or less.

Further, the content ratio of the first inorganic particles is, for example, 2.5% by mass or more, preferably 5% by mass or more, more preferably, with respect to the intermediate layer 4 (that is, the solid content of the particle resin composition). 7% by mass or more, more preferably 7.5% by mass or more, particularly preferably 9% by mass or more, and for example, 23% by mass or less, preferably 17% by mass or less, more preferably 15% by mass. % Or less.

The content ratio of the second inorganic particles to the first inorganic particles (ratio, the number of parts by mass of the second inorganic particles / the number of parts by mass of the first inorganic particles) is, for example, 0.06 or more, preferably 0.1 or more. It is preferably 0.15 or more, more preferably 0.2 or more, and for example, 0.45 or less, preferably 0.4 or less, and more preferably 0.3 or less.

When the content ratio of the second inorganic particles is at least the above lower limit, the transparent conductive film 1 can have excellent blocking resistance. On the other hand, if the content ratio of the second inorganic particles is not more than the above upper limit, the haze of the intermediate layer 4 can be lowered.

The content ratio of the total amount of the first inorganic particles and the second inorganic particles to 100 parts by mass of the resin is, for example, 85 parts by mass or more, preferably 100 parts by mass or more, and for example, 260 parts by mass or less, preferably 260 parts by mass or less. , 200 parts by mass or less. When the content ratio of the total amount of the first inorganic particles and the second inorganic particles is equal to or higher than the above lower limit, the total light transmittance of the transparent conductive film 1 can be increased. When the content ratio of the total amount of the first inorganic particles and the second inorganic particles is not more than the above-mentioned upper limit, the reflected hue of the transparent conductive film 1 can be made more neutral.

4-3. Resin The resin is not particularly limited, and examples thereof include a curable resin and a thermoplastic resin (for example, a polyolefin resin), and a curable resin is preferable.

Examples of the curable resin include an active energy ray-curable resin that is cured by irradiation with active energy rays (specifically, ultraviolet rays, electron beams, etc.), for example, a thermosetting resin that is cured by heating. An active energy ray-curable resin is preferable, and an ultraviolet curable resin is more preferable.

Specific examples of the active energy ray-curable resin include (meth) acrylic ultraviolet curable resins such as urethane acrylates and epoxy acrylates, such as urethane resins, for example, melamine resins, for example, alkyd resins, for example. Examples thereof include siloxane-based polymers such as organic silane condensates. Preferred are (meth) acrylic UV curable resins, more preferably urethane acrylates.

These resins can be used alone or in combination of two or more.

The resin content is the balance of the content of the first inorganic particles and the second inorganic particles. Specifically, the content ratio of the resin is, for example, 25% by mass or more, preferably 30% by mass or more, with respect to the intermediate layer 4 (that is, the solid content of the particle resin composition), and for example. It is 60% by mass or less, preferably 55% by mass or less.

4-4. Method for Producing Intermediate Layer To prepare the intermediate layer 4, for example, first, the above-mentioned particle resin composition is prepared. Preferably, the first inorganic particles, the second inorganic particles, the resin and the solvent are blended to prepare a particle resin composition solution (coating liquid, coating liquid for forming an intermediate layer).

Examples of the solvent include organic solvents, and such organic solvents are not particularly limited, and are alcohol-based solvents such as, for example, methanol, isopropyl alcohol, butanol, ethylene glycol, ethylene glycol-monopropyl ether, and propylene glycol monomethyl ether. For example, a ketone solvent such as methyl ethyl ketone and methyl isobutyl ketone, for example, an ester solvent such as ethyl acetate and butyl acetate, and an aromatic solvent such as xylene and toluene can be mentioned.

In order to prepare the particle resin composition solution (coating liquid), for example, a particle resin mixture in which a resin and one of the first inorganic particles and the second inorganic particles are mixed in advance is prepared, and the particle resin mixture is prepared. And the other (inorganic particles) are mixed. At this time, the solvent may be blended together with any of the above-mentioned raw materials (resin, first inorganic particles, or second inorganic particles). Alternatively, the solvent can be added after the raw material is prepared.

Alternatively, first, the resin and the solvent are mixed to prepare a resin solution, and then the first inorganic particles and the second inorganic particles are mixed in the resin solution. Further, the resin is blended with the first inorganic particles, the second inorganic particles and a solvent.

Preferably, a particle resin mixture in which the resin and the first inorganic particles are premixed (first particle resin mixture) and a particle resin mixture in which the resin and the second inorganic particles are premixed (second particle resin mixture). , Then they are mixed, and then the solvent is added to prepare the coating solution and adjust the solid content in the coating solution. The solid content in the coating liquid is, for example, 0.1% by mass or more, preferably 1% by mass or more, and for example, 30% by mass or less, preferably 15% by mass or less.

As the particle resin mixture (first particle resin mixture or second particle resin mixture), a commercially available product can be used, and specifically, Opstar series (manufactured by Arakawa Chemical Co., Ltd.) or the like is used.

Then, the particle resin composition solution is applied to the entire upper surface of the hard coat layer 3.

Then, the solvent is removed by heating. The heating temperature is, for example, 50 ° C. or higher, preferably 55 ° C. or higher, and for example, 100 ° C. or lower, preferably 80 ° C. or lower. The heating time is, for example, 10 seconds or more, preferably 20 seconds or more, and, for example, 5 minutes or less, preferably 3 minutes or less.

As a result, a coating film made of the particle resin composition is formed.

Then, when the particle resin composition contains an active energy ray-curable resin, the coating film is irradiated with active energy rays. This cures the resin.

As a result, the intermediate layer 4 is formed on the upper surface of the hard coat layer 3.

The first inorganic particles and the second inorganic particles contained in the intermediate layer 4 are qualitatively analyzed (identified) by, for example, burning the intermediate layer 4 and then performing an elemental analysis of the obtained ash. The first inorganic particles and the second inorganic particles are quantitatively analyzed by measuring their particle sizes with a laser diffraction type particle size distribution measuring device or the like. In the above quantitative analysis, a particle size distribution curve having two peaks based on two median diameters of the first inorganic particle and the second inorganic particle is obtained, and from those peaks, the first inorganic particle and the second inorganic particle are obtained. The median diameter and compounding ratio are obtained, respectively.

4-5. Physical characteristics of the intermediate layer The haze of the intermediate layer 4 is, for example, 0.7 or less, preferably 0.6 or less, more preferably 0.5 or less, still more preferably 0.4 or less, and for example. It is over 0. If the haze of the intermediate layer 4 is less than the above-mentioned upper limit, the transparent conductive film 1 is excellent in optical characteristics. A method for measuring the haze of the intermediate layer 4 will be described in a later example.

The roughness (surface roughness) of the upper surface of the intermediate layer 4 is, for example, 10 nm or less, preferably 6 nm or less, and for example, 0.3 nm or more, preferably 0.5 nm or more.

The thickness of the intermediate layer 4 is, for example, less than 500 nm, preferably 300 nm or less, more preferably 200 nm or less, still more preferably 140 nm or less, particularly preferably 120 nm or less, and most preferably 105 nm or less. The thickness of the intermediate layer 4 is, for example, 10 nm or more, preferably 50 nm or more, and more preferably 60 nm or more. If the thickness of the intermediate layer 4 is less than the above-mentioned upper limit, the thickness of the transparent conductive film 1 can be reduced. Furthermore, if the thickness of the intermediate layer 4 is less than the above-mentioned upper limit, it is possible to thin the pattern portion (described later) formed from the transparent conductive layer 5.

5. Transparent conductive layer The transparent conductive layer 5 is an upper layer of the transparent conductive film 1, and specifically, is arranged above the transparent base material 2. The transparent conductive layer 5 is a conductive layer for forming a pattern portion (not shown) by forming a pattern in a later step. The transparent conductive layer 5 has a film shape (including a sheet shape) extending in the surface direction, and has a flat lower surface and a flat upper surface. The transparent conductive layer 5 is in direct contact with the entire upper surface of the intermediate layer 4.

The material for forming the transparent conductive layer 5 is at least selected from the group consisting of, for example, In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. Examples include metal oxides containing one type of metal. The metal oxide can be further doped with the metal atoms shown in the above group, if necessary.

As the material, indium tin composite oxide (ITO), antimony tin composite oxide (ATO) and the like are preferable, and ITO is more preferable.

The thickness of the transparent conductive layer 5 is, for example, 10 nm or more, preferably 20 nm or more, and for example, 35 nm or less, preferably 30 nm or less.

The transparent conductive layer 5 is formed on the entire upper surface of the intermediate layer 4 by a known method.

As a result, the transparent conductive film 1 including the transparent base material 2, the hard coat layer 3, the intermediate layer 4, and the transparent conductive layer 5 in this order can be obtained.

6. Method and Physical Properties of Transparent Conductive Film This transparent conductive film 1 is obtained by arranging a hard coat layer 3, an intermediate layer 4 and a transparent conductive layer 5 in this order on the upper side of the transparent base material 2. The method for producing the transparent conductive film 1 is a roll-to-roll method. Moreover, it is also possible to carry out a part or all in a batch method.

The thickness of the transparent conductive film 1 is, for example, 200 μm or less, preferably 150 μm or less, and for example, 20 μm or more, preferably 30 μm or more.

7. Use of Transparent Conductive Film Such a transparent conductive film 1 is provided in, for example, an image display device.

In particular, the transparent conductive film 1 is used, for example, as a base material for a touch panel. Examples of the touch panel type include various methods such as an optical method, an ultrasonic method, a capacitance method, and a resistance film method. The transparent conductive film 1 is particularly preferably used for a capacitance type touch panel.

Specifically, first, the transparent conductive layer 5 of the transparent conductive film 1 is removed by, for example, etching to form a patterned portion (not shown) and a non-patterned portion (not shown). ..

The reflectance difference ΔR between the patterned portion and the non-patterned portion of the transparent conductive film 1 is an absolute value thereof, for example, 2 or less, preferably 1.5 or less, more preferably 1.0 or less, still more preferably. , 0.5 or less. When the reflectance difference ΔR is equal to or less than the above upper limit, visual recognition in the pattern portion of the transparent conductive layer 5 can be suppressed. The reflectance difference ΔR in the transparent conductive film 1 is a value obtained by subtracting the reflectance R2 of the non-patterned portion from the reflectance R1 of the patterned portion, and is, for example, by the method described in JP-A-2015-166184. Desired.

After that, the transparent conductive film 1 is provided in the image display device described above.

8. Action effect In this transparent conductive film 1, the intermediate layer 4 has a first inorganic particle having a median diameter of 5 nm or more and less than 45 nm, a second inorganic particle having a median diameter of 45 nm or more and less than 120 nm, and a resin. Since it contains, it is excellent in both blocking resistance and optical characteristics.

On the other hand, in Patent Document 1, it is necessary to provide two layers, an anti-blocking layer and a color difference adjusting layer, which causes a problem that the layer structure becomes complicated.

However, in this transparent conductive film 1, since the intermediate layer 4 is a blocking-resistant optical adjustment layer, the transparent conductive film 1 is transparently conductive while reliably imparting blocking resistance to the transparent conductive film 1 while having a simple layer structure. The visibility of the pattern in the layer 5 can be reliably suppressed.

Further, in the transparent conductive film 1, the content ratio of the first inorganic particles to 100 parts by mass of the resin is 65 parts by mass or more and 235 parts by mass or less, and the content ratio of the second inorganic particles to 100 parts by mass of the resin. However, it is 5 parts by mass or more and 80 parts by mass or less. Therefore, the transparent conductive film 1 can have excellent blocking resistance and an excellent appearance while suppressing the pattern visibility of the transparent conductive layer 5.

As a result, the transparent conductive film 1 has a simple layer structure and is excellent in both blocking resistance and optical properties.

Further, in the transparent conductive film 1, if the content ratio of the first inorganic particles and the second inorganic particles to 100 parts by mass of the resin is 85 parts by mass or more, the total light transmittance of the transparent conductive film 1 is increased. If it is 260 parts by mass or less, the reflected hue of the transparent conductive film 1 can be made more neutral.

Further, in the transparent conductive film 1, if the thickness of the intermediate layer 4 is less than 500 nm, the thickness of the transparent conductive film 1 can be reduced. Furthermore, if the thickness of the intermediate layer 4 is 200 nm or less, the pattern portion formed from the transparent conductive layer 5 can be thinned.

Furthermore, in the transparent conductive film 1, if the first inorganic particles and the second inorganic particles are both zirconia particles, the intermediate layer 4 can be easily optically adjusted, and a high-quality transparent conductive film 1 can be obtained. be able to.

Further, since the transparent conductive film 1 includes the hard coat layer 3, the scratch resistance of the transparent conductive film 1 can be improved.

Further, in the transparent conductive film 1, the hard coat layer 3 has a plurality of protrusions on its surface, and if the maximum protrusion length of the protrusions per 1 cm ² of the hard coat layer 31 is 200 nm or less, the hard coat layer 3 is hard coated. The smoothness of the layer 3 can be ensured, and haze can be suppressed.

9. Modified Examples In the modified examples, the same members and processes as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In one embodiment shown in FIG. 1, the transparent conductive film 1 includes a hard coat layer 3, an intermediate layer 4, and a transparent conductive layer 5 arranged only on the upper side of the transparent base material 2. However, the arrangement of the hard coat layer 3, the intermediate layer 4 and the transparent conductive layer 5 is not limited to the above, and for example, as shown in FIG. A coat layer 3, an intermediate layer 4, and a transparent conductive layer 5 can also be provided. That is, as shown in FIG. 2, the transparent conductive film 1 has a transparent base material 2, two transparent conductive layers 5 arranged on both sides of the transparent base material 2, a transparent base material 2 and a transparent conductive layer 5. It is provided with two hard coat layers 3 and two intermediate layers 4 interposed between the two.

The modification shown in FIG. 2 can also have the same effect as that of the embodiment shown in FIG.

Further, in one embodiment shown in FIG. 1, the transparent conductive film 1 includes a hard coat layer 3. However, as shown in FIG. 3, the transparent conductive film 1 does not include the hard coat layer 3, but may include only the transparent base material 2, the intermediate layer 4, and the transparent conductive layer 5 in this order. In this modification, the transparent conductive film 1 preferably comprises only the transparent base material 2, the intermediate layer 4, and the transparent conductive layer 5. The intermediate layer 4 is arranged on the upper surface of the transparent base material 2. Specifically, the intermediate layer 4 is in direct contact with the entire upper surface of the transparent base material 2.

The modified example shown in FIG. 3 can also have the same effect as that of the embodiment shown in FIG.

Further, as shown in FIG. 4, the transparent conductive film 1 may also include an intermediate layer 4 and a transparent conductive layer 5 which are sequentially arranged on both upper and lower sides of the transparent base material 2. As shown in FIG. 4, the transparent conductive film 1 is interposed between the transparent base material 2, the transparent conductive layers 5 arranged on both sides of the transparent base material 2, and the transparent base material 2 and the transparent conductive layer 5. The intermediate layer 4 is provided.

The modified example shown in FIG. 4 can also have the same effect as that of the embodiment shown in FIG.

The above-mentioned modification examples can be combined as appropriate.

For example, the hard coat layer 3, the intermediate layer 4, and the transparent conductive layer 5 are provided on the upper side of the transparent base material 2 as shown in FIG. 1, while the transparent base material 2 is provided as shown in FIG. Only the intermediate layer 4 and the transparent conductive layer 5 may be provided on the lower side.

Examples and comparative examples are shown below, and the present invention will be described in more detail. The present invention is not limited to Examples and Comparative Examples. In addition, specific numerical values such as the compounding ratio (content ratio), physical property values, and parameters used in the following description are the compounding ratios corresponding to those described in the above-mentioned "Form for carrying out the invention". Substitute the upper limit value (value defined as "less than or equal to" or "less than") or the lower limit value (value defined as "greater than or equal to" or "excess") such as content ratio), physical property value, and parameters. be able to.

(Preparation of coating liquid)
Preparation Example 1
A first particle resin mixture containing urethane acrylate as an ultraviolet curable resin and zirconia particles having a median diameter of 30 nm as first inorganic particles (manufactured by Arakawa Chemical Industry Co., Ltd., product name "Opstar Z7412", content ratio of first inorganic particles) A second particle resin mixture (manufactured by Arakawa Chemical Industry Co., Ltd., product name "Opstar KZ6941") in which urethane acrylate as an ultraviolet curable resin and zirconia particles having a median diameter of 64 nm as second inorganic particles are previously blended. , The content ratio of the second inorganic particles: 47% by mass) was mixed at the blending ratio shown in Table 1, and further, a solvent (butyl acetate) was blended so that the solid content concentration was 3.5% by mass. A mixed coating liquid (coating liquid for forming an intermediate layer) was prepared.

Preparation Example 2-Comparative Preparation Example 2
A coating liquid (coating liquid for forming an intermediate layer) was prepared in the same manner as in Preparation Example 1 except that the blending ratios of the first particle resin mixture and the second particle resin mixture were changed according to Table 1.

Details of each coating liquid in Table 1 are shown below.

Opstar Z7412: First particle resin mixture, content ratio of zirconia particles (first inorganic particles) with a median diameter of 30 nm 47% by mass
Opstar KZ6954: First particle resin mixture, zirconia particles with a median diameter of 25 nm (first inorganic particles, large diameter particles) content ratio of 54% by mass, silica particles with a median diameter of 10 nm (first inorganic particles, small diameter particles) Content ratio 13% by mass
Opstar KZ6734: First particle resin mixture, content ratio of zirconia particles (first inorganic particles) with a median diameter of 30 nm 72% by mass
Opstar KZ6956: Second particle resin mixture, content ratio of zirconia particles (first inorganic particles) with a median diameter of 25 nm 54% by mass
Opstar KZ6941: Second particle resin mixture, content ratio of zirconia particles (first inorganic particles) with a median diameter of 64 nm 47% by mass
Opstar RA009: Second particle resin mixture, content ratio of zirconia particles (first inorganic particles) with a median diameter of 64 nm 54% by mass
Opstar RA010: Second particle resin mixture, content ratio of zirconia particles (first inorganic particles) with a median diameter of 64 nm 72% by mass
Example 1
A 1 μm-thick hard coat layer 3 made of an organic-inorganic hybrid resin (KZ6506 JSR) was provided on the upper surface of a 100 μm-thick COP film (ZEONOR ZF-16, manufactured by Nippon Zeon Co., Ltd.) as the transparent base material 2.

Next, the coating liquid of Preparation Example 1 was applied to the upper surface of the hard coat layer 3 using a wire bar, dried in a drying oven at 60 ° C. for 1 minute, and the solvent was volatilized to form a coating film. did. Thereafter, a coating film, using an oxygen concentration 2500ppm atmosphere at 160 W / cm ² of air-cooled mercury lamp (manufactured by Eye Graphics Co., Ltd.), ultraviolet illuminance 60 mW / cm ^2, was irradiated with irradiation dose 280 mJ / cm ² , The coating film was cured.

As a result, the intermediate layer 4 having a thickness of 85 nm was formed on the upper surface of the hard coat layer 3.

Then, a transparent conductive layer 5 made of ITO having a thickness of 25 nm was formed on the upper surface of the intermediate layer 4.

As a result, the transparent conductive film 1 was obtained.

Example 2 to Comparative Example 2
A transparent conductive film 1 was obtained in the same manner as in Example 1 except that the formulation of the intermediate layer 4 was changed based on Table 2.

(Evaluation)
The following items were measured. The results are shown in Table 2.

(Thickness of intermediate layer)
The thickness of the intermediate layer 4 was determined from the peak wavelength of the reflection spectrum obtained by a spectrophotometer (model number "U4100", manufactured by Hitachi High-Technologies Corporation).

(Blocking resistance)
A COP film (ZEONOR film ZF-16, manufactured by ZEON Corporation) was pressure-bonded to the intermediate layer 4 with a finger, the degree of adhesion was observed, and the blocking resistance was evaluated according to the following criteria.
◯: The COP film does not stick.
Δ: COP film sticking occurs once, but after 10 seconds, the COP film separates from the intermediate layer 4.
X: The COP film was stuck, and the COP film did not separate from the intermediate layer 4 even after 10 seconds had passed.

(Middle layer haze)
The haze of the transparent conductive film 1 after the intermediate layer 4 was formed and before the transparent conductive layer 5 was formed was measured by a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute).

(Refractive index of intermediate layer)
The refractive index of the intermediate layer 4 was determined by a high-speed spectroscopic ellipsometer (M-2000, manufactured by JA Woolam).

(Surface roughness of hard coat layer)
The surface roughness of the hard coat layer 3 was determined by AFM (manufactured by Digital Instruments).

1 Transparent conductive film 2 Transparent base material 3 Hard coat layer 4 Intermediate layer 5 Transparent conductive layer

Claims (7)

A transparent base material, a transparent conductive layer arranged on one side or both sides of the transparent base material, and an intermediate layer interposed between the transparent base material and the transparent conductive layer are provided.
The intermediate layer
First inorganic particles having a median diameter of 5 nm or more and less than 45 nm,
Second inorganic particles having a median diameter of 45 nm or more and less than 120 nm,
Including resin
The content ratio of the first inorganic particles to 100 parts by mass of the resin is 65 parts by mass or more and 235 parts by mass or less.
A transparent conductive film characterized in that the content ratio of the second inorganic particles to 100 parts by mass of the resin is 5 parts by mass or more and 80 parts by mass or less. The transparent conductive film according to claim 1, wherein the content ratio of the first inorganic particles and the second inorganic particles to 100 parts by mass of the resin is 85 parts by mass or more and 260 parts by mass or less. .. The transparent conductive film according to claim 1 or 2, wherein the intermediate layer has a thickness of less than 500 nm. The transparent conductive film according to any one of claims 1 to 3, wherein the intermediate layer is a blocking-resistant optical adjustment layer. The transparent conductive film according to any one of claims 1 to 4, wherein the first inorganic particles and the second inorganic particles are both zirconia particles. The transparent conductive film according to any one of claims 1 to 5, further comprising a hard coat layer interposed between the transparent base material and the intermediate layer. The hard coat layer has a plurality of protrusions on its surface and has a plurality of protrusions.
The transparent conductive film according to claim 6, wherein the maximum protrusion length of the protrusions per 1 cm ^{2 of the} hard coat layer is 200 nm or less.

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