TW202000759A - Hard coat film and transparent conductive film for providing both excellent bending resistance and scratch resistance, and excellent flexibility - Google Patents

Abstract

The hard coat film of the present invention is provided with a transparent substrate and a hard coat layer sequentially in the thickness direction. The hard coat layer includes a resin matrix and particles. The hardness of the hard coat layer measured by the nano-indentation method is 0.320 GPa or more and 0.520 GPa or less. The pencil hardness of the hard coat layer is B or less. Therefore, the hard coat film is provided with both excellent bending resistance and scratch resistance, and excellent flexibility.

Description

Hard coating film and transparent conductive film

The present invention relates to a hard coating film and a transparent conductive film. Specifically, it relates to a hard coating film and a transparent conductive film provided with the hard coating film.

Conventionally, a hard coating film having a hard coating layer on one side of a transparent resin substrate has been known.

For example, there is disclosed a hard coating film having a hard coating layer having an elastic modulus of 2.1 to 5.0 GPa (for example, refer to Japanese Patent Laid-Open No. 2014-25061).

However, the hard coating layer is required to have excellent bending resistance, but the hard coating film described in Japanese Patent Laid-Open No. 2014-25061 has a high elastic modulus of the hard coating layer of 2.1 to 5.0 GPa, so it is impossible Fully meet the above requirements.

On the other hand, the hard coating film is also required to have excellent scratch resistance.

Furthermore, the hard coating film is also required to have excellent bending resistance and scratch resistance, and be soft.

The present invention provides a hard coating film having excellent bending resistance, scratch resistance, and excellent flexibility, and a transparent conductive film provided with the hard coating film.

The present invention (1) includes a hard coating film that is sequentially provided with a transparent substrate and a hard coating layer in the thickness direction. The hard coating layer includes a resin matrix and particles, and the hard coating layer is measured by a nanoindentation method The hardness is 0.320 GPa or more and 0.520 GPa or less, and the pencil hardness of the hard coat layer is B or less.

The present invention (2) includes the hard coating film as described in (1), wherein the thickness of the hard coating layer is 3 μm or less.

The present invention (3) includes the hard coating film as described in (1) or (2), wherein the arithmetic average roughness Ra of the hard coating layer is 3 nm or more and 14 nm or less.

The present invention (4) includes the hard coating film according to any one of (1) to (3), wherein the material of the transparent substrate is a cycloolefin polymer.

The present invention (5) includes a transparent conductive film including the hard coating film, the optical adjustment layer, and the transparent conductive layer as described in any one of (1) to (4) in the thickness direction.

The hard coating film and the transparent conductive film of the present invention have excellent hardness and scratch resistance as well as a hardness of 0.320 GPa or more and 0.520 GPa or less, and a pencil hardness of the hard coat layer of B or less. Excellent softness.

One embodiment of the hard coating film of the present invention will be described with reference to FIG.

The hard coating film 1 has one surface and the other surface (two main surfaces) facing each other spaced apart in the thickness direction. One side and the other side of the hard coating film 1 are planes parallel to each other. The hard coating film 1 has a substantially film shape extending in a plane direction orthogonal to the thickness direction.

The hard coating film 1 is, for example, one of the components included in the transparent conductive film 6 (see FIG. 2) described below. In short, it is not the transparent conductive film 6. That is, the hard coating film 1 is a component used for manufacturing the transparent conductive film 6, does not include the optical adjustment layer 4 and the transparent conductive layer 5, and is circulated as a component alone, and is an element that can be industrially used.

The hard coating film 1 includes a transparent base material 2 and a hard coating layer 3 in this order toward one side in the thickness direction. That is, the hard coating film 1 includes the transparent base material 2 and the hard coat layer 3 disposed on one surface in the thickness direction of the transparent base material 2. Moreover, it is preferable that the hard coating film 1 includes only the transparent substrate 2 and the hard coating layer 3.

The transparent substrate 2 forms the other surface of the hard coating film 1. Specifically, the transparent substrate 2 is a supporting material that ensures the mechanical strength of the hard coating film 1. The transparent substrate 2 has a film shape extending in the plane direction. The transparent base material 2 has one surface and the other surface which are opposed to each other and spaced apart in the thickness direction. One side and the other side of the transparent substrate 2 are planes parallel to each other. The other surface of the transparent substrate 2 in the thickness direction is exposed on the other side in the thickness direction.

The material of the transparent substrate 2 is not particularly limited as long as it is transparent. Examples of the material of the transparent substrate 2 include resin (including polymer). Examples of the resin include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and (meth)acrylic resins such as polymethacrylate. (Acrylic resin and/or methacrylic resin), olefin resins such as polyethylene, polypropylene, cycloolefin polymer (COP), such as polycarbonate resins, such as polyether resins, such as polyarylate resins, such as melamine Resins, such as polyamido resins, such as polyimide resins, such as cellulose resins, such as polystyrene resins, such as norbornene resins, and the like. These resins can be used alone or in combination of two or more. From the viewpoint of ensuring excellent optical characteristics (including transparency), olefin resins are preferably mentioned, and COP is more preferable.

COP is superior to polyester resin in optical properties (isotropy). On the other hand, COP has lower mechanical strength (easy to break) than polyester resin. However, since the hard coating film 1 has the hard coating layer 3 having the required hardness and pencil hardness, even if the mechanical strength of the transparent substrate 2 is low, the hard coating film 1 can suppress a large decrease in mechanical strength (cracked produce).

The total light transmittance (JIS K 7375-2008) of the transparent substrate 2 is, for example, 80% or more, preferably 85% or more.

The thickness of the transparent substrate 2 is the length between one side and the other side (the same in each layer below), specifically, for example, 2 μm or more, preferably 20 μm or more, and for example 300 μm or less, preferably It is less than 200 μm.

The hard coat layer 3 forms one side of the hard coat film 1. Specifically, the hard coat layer 3 is a hard layer that provides the hard coating film 1 with excellent bending resistance and also ensures excellent scratch resistance. In addition, the hard coat layer 3 is also an anti-adhesion layer that imparts anti-adhesion properties to the hard coating film 1. The hard coat layer 3 has a film shape extending in the plane direction. The hard coat layer 3 has one surface and the other surface facing each other in the thickness direction. The other surface of the hard coat layer 3 is in contact with one surface of the transparent substrate 2. One surface of the hard coat layer 3 is exposed on one side in the thickness direction of the hard coat film 1, for example, and has a fine uneven shape (not shown in FIG. 1).

The hard coat layer 3 contains resin and particles. The hard coat layer 3 preferably contains only resin and particles. Specifically, the material of the hard coat layer 3 is a composition containing resin and particles.

The resin is not particularly limited as long as it is a transparent resin, and examples thereof include curable resins and thermoplastic resins, preferably curable resins, and more preferably photocurable resins. Examples of the photocurable resins include acrylic resins, epoxy resins, and silicone resins. From the viewpoint of ensuring excellent optical characteristics and excellent mechanical strength, acrylic resins are preferably used. These resins can be used alone or in combination of two or more.

The material of the particles is not particularly limited, as long as it is transparent, and examples include organic materials and inorganic materials. Examples of organic materials include polymers such as acrylic polymers and polystyrene, and preferably acrylic polymers. Examples of the inorganic material include silicon oxide, metal oxides including zirconia, titanium oxide, zinc oxide, and tin oxide, and carbonates such as calcium carbonate. Preferably, silicon oxide is used. These materials can be used alone or in combination of two or more.

The shape of the particles is not particularly limited, and examples thereof include a substantially spherical shape, a substantially needle shape, a substantially plate shape, and an indefinite shape, and preferably a substantially spherical shape.

The average value of the maximum length of the particles (the average particle diameter if it is roughly spherical) is preferably smaller, more preferably the nanometer size. Specifically, the average value of the maximum length of the particles is, for example, 100 nm or less, preferably 80 nm or less, more preferably 60 nm or less, and for example, 1 nm or more, preferably 5 nm or more, more preferably 10 Above nm.

If the average value of the maximum length of the particles is equal to or less than the above upper limit, the arithmetic mean roughness Ra of one surface of the hard coat layer 3 described below can be easily and surely set to a desired range.

If the average value of the maximum length of the particles is equal to or higher than the above lower limit, the hard coating film 1 can be given excellent anti-blocking properties.

Furthermore, the hard coat layer 3 is formed from the above composition, and the hard coat layer 3 is provided with a resin matrix and particles dispersed in the resin matrix.

The number of parts by mass of particles is, for example, 0.1 parts by mass or more, preferably 1 part by mass or more, and, for example, 75 parts by mass or less, preferably 55 parts by mass or less relative to 100 parts by mass of the resin.

The hardness of the hard coat layer 3 is 0.320 GPa or more, preferably 0.350 GPa or more, and more preferably 0.360 GPa or more. If the hardness of the hard coating layer 3 is lower than the above lower limit, the hard coating film 1 cannot ensure excellent scratch resistance.

The hardness of the hard coat layer 3 is 0.520 GPa or less, preferably 0.500 GPa or less, more preferably 0.450 GPa or less, and further preferably 0.400 GPa or less, and particularly preferably 0.370 GPa or less. If the hardness of the hard coat layer 3 exceeds the upper limit described above, the hard coat film 1 cannot ensure excellent bending resistance.

The hardness of the hard coat layer 3 is the indentation hardness at 23° C. measured by the nano indentation method, specifically, the indentation obtained by pressing the nano indenter (indenter) against the hard coat layer 3 at 23° C. hardness. The method of measuring the hardness is described in detail in the following examples.

In addition, the pencil hardness of the hard coat layer 3 is B or less, preferably 2B or less, more preferably 3B or less, further preferably 4B or less, and particularly preferably 5B or less. Furthermore, the pencil hardness of the hard coat layer 3 is, for example, 10B or more, and further 9B or more.

When the pencil hardness of the hard coat layer 3 exceeds the upper limit (B) (more than B), the excellent softness of the hard coat layer 3 cannot be ensured.

The pencil hardness of the hard coat layer 3 is measured in accordance with JIS K5600-5-4 "Scratch Hardness (Pencil Method)" (1999).

The arithmetic average roughness Ra of one surface of the hard coat layer 3 is, for example, 1 nm or more, preferably 3 nm or more, more preferably 5 nm or more, and for example 20 nm or less, preferably 14 nm or less, more preferably 12 Below nm.

If the arithmetic average roughness Ra of one surface of the hard coat layer 3 is equal to or greater than the above lower limit, the hard coating film 1 can be provided with excellent blocking resistance.

If the arithmetic average roughness Ra of one surface of the hard coat layer 3 is equal to or lower than the above upper limit, the increase in the haze of the hard coat film 1 can be suppressed, and excellent transparency can be ensured.

The arithmetic average roughness Ra of the hard coat layer 3 is measured in accordance with JIS B 0601 (2013).

The hard coat layer 3 is preferably thin. Specifically, the thickness of the hard coat layer 3 is, for example, less than 10 μm, preferably 9 μm or less, more preferably 7 μm or less, and further preferably 5 μm or less, particularly preferably 3 μm or less, and most preferably 2 μm the following. If the thickness of the hard coat layer 3 is equal to or less than the above-mentioned upper limit, excellent bending resistance can be ensured.

The thickness of the hard coat layer 3 is, for example, 0.001 μm or more, preferably 0.01 μm or more, more preferably 0.1 μm or more, and still more preferably 0.5 μm or more. If the thickness of the hard coat layer 3 is more than the above lower limit, the scratch resistance of the hard coat layer 3 can be improved.

The thickness of the hard coat layer 3 was measured using Intensified Multichannel Photodetector "MCPD2000" (trade name) manufactured by Otsuka Electronics Co., Ltd.

When the thickness of the hard coating film 1 is 101 μm, for example, it is less than 0.5, preferably 0.40 or less, more preferably 0.30 or less, further preferably 0.20 or less, particularly preferably 0.15 or less, and usually 0.01 or more .

If the haze of the hard coating film 1 is lower than the above upper limit, the hard coating film 1 is excellent in transparency.

The thickness of the hard coating film 1 is, for example, 150 μm or less, preferably 125 μm or less, and for example, 5 μm or more, preferably 10 μm or more.

To manufacture the hard coating film 1, for example, the transparent substrate 2 is prepared first, and then, the composition is disposed on one surface in the thickness direction of the transparent substrate 2 by, for example, a wet method.

Specifically, first, a coating liquid (varnish) obtained by diluting the composition with a solvent is prepared. A mixture (commercially available product) in which the particles are dispersed in the resin in advance can be prepared (prepared) as a coating liquid, or the particles can be mixed with the resin and the particles can be dispersed in the resin to prepare. Furthermore, if necessary, an initiator may be added to the coating liquid, or a resin to which an initiator has been added in advance may be used.

Then, a coating liquid (varnish) is applied to one surface of the transparent substrate 2 in the thickness direction. Thereafter, the solvent is removed by heating, and then, when the composition contains a curable resin, the curable resin is cured. With this, the hard coat layer 3 in which particles are dispersed in the resin matrix is formed.

With this, the hard coat layer 3 is formed on one surface of the transparent substrate 2 in the thickness direction.

By this, the hard coating film 1 provided with the transparent base material 2 and the hard coating layer 3 is manufactured.

The hard coating film 1 can be used for various industrial applications, for example, for optical applications such as transparent conductive films and dimming films, and further for electromagnetic shielding applications. It is preferably used for optical applications, and more preferably used for transparent conductive films.

Next, the transparent conductive film 6 provided with the hard coating film 1 will be described with reference to FIG. 2.

The transparent conductive film 6 has one surface and the other surface (two main surfaces) facing each other spaced apart in the thickness direction. One side and the other side of the transparent conductive film 6 are planes parallel to each other. The transparent conductive film 6 has a substantially film shape extending in the plane direction. The transparent conductive film 6 is, for example, a component such as a touch panel base material or a dimming panel included in an optical device (for example, an image display device or a dimming device), but it is not an optical device in general. That is, the transparent conductive film 6 is a component used for manufacturing an optical device and the like, does not include an image display element such as an LCD module or a light source such as an LED, and is circulated as a component alone, and is an element that can be industrially used.

The transparent conductive film 6 includes a hard coating film 1, an optical adjustment layer 4 and a transparent conductive layer 5 in this order toward one side in the thickness direction. Specifically, the transparent conductive film 6 includes a transparent substrate 2, a hard coat layer 3, an optical adjustment layer 4, and a transparent conductive layer 5 in this order toward one side in the thickness direction. Preferably, the transparent conductive film 6 includes only the transparent substrate 2, the hard coat layer 3, the optical adjustment layer 4 and the transparent conductive layer 5.

The optical adjustment layer 4 is a layer for adjusting the optical properties of the transparent conductive film 6 (refractive index matching layer), which makes it impossible to distinguish between the non-pattern portion and the pattern portion after the transparent conductive layer 5 is formed as a wiring pattern in the subsequent step Difference (ie, suppress the visibility of the wiring pattern). The optical adjustment layer 4 has a film shape extending in the plane direction, and has one side and the other side facing each other and spaced apart in the thickness direction. Examples of the material of the optical adjustment layer 4 include the above-mentioned resin (without particles) and the above-mentioned composition (with particles). The thickness of the optical adjustment layer 4 is, for example, 30 nm or more, preferably 80 nm or more, and for example 150 nm or less, preferably 130 nm or less.

The transparent conductive layer 5 is a conductive layer for forming a wiring pattern and forming a pattern portion in a subsequent step. The transparent conductive layer 5 forms a surface in the thickness direction of the transparent conductive film 6. The transparent conductive layer 5 has a film shape (including a sheet shape) extending in the plane direction, and has one side and the other side facing each other spaced apart in the thickness direction.

As a material of the transparent conductive layer 5, for example, it may include: selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W Metal oxide of at least one metal. Furthermore, if necessary, the metal oxide is doped with the metal atoms shown in the above group. As the material, preferably, indium-tin composite oxide (ITO), antimony-tin composite oxide (ATO), etc. are mentioned.

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 thickness of the transparent conductive film 6 is, for example, 150 μm or less, preferably 125 μm or less, and for example, 5 μm or more, preferably 10 μm or more.

In order to manufacture the transparent conductive film 6, the optical adjustment layer 4 and the transparent conductive layer 5 are sequentially arranged on one surface of the hard coat layer 3 in the thickness direction of the hard coating film 1 according to a known method.

In addition, in the hard coating film 1 and the transparent conductive film 6, the hardness of the hard coating layer 3 is 0.320 GPa or more, so excellent scratch resistance can be ensured.

In addition, the hardness of the hard coat layer 3 is 0.520 GPa or less, so that excellent bending resistance can be ensured.

Furthermore, the pencil hardness of the hard coat layer 3 is B or less, so it has excellent bending resistance and scratch resistance, and can ensure flexibility.

In addition, if the thickness of the hard coat layer 3 is 3 μm or less, excellent bending resistance can be ensured.

In addition, if the arithmetic average roughness Ra of the hard coat layer 3 is 3 nm or more and 14 nm or less, the hard coating film 1 can be provided with excellent anti-blocking property, and the excellent transparency of the hard coating film 1 can be ensured.

If the material of the transparent substrate 2 is COP, the transparent substrate 2 is excellent in optical characteristics. On the other hand, although the mechanical strength becomes low (it becomes easy to break), the hard coating film 1 has the above-mentioned hardness and pencil hardness. The hard coating layer 3 can suppress a large decrease in the mechanical strength of the hard coating layer 3 in the hard coating film 1 (the occurrence of cracks).

Variations In each of the following modifications, the same reference numerals are given to the same components and steps as in the above-mentioned embodiment, and detailed descriptions thereof are omitted. In addition, each modified example can exert the same effect as the first embodiment except for special marks. Furthermore, an embodiment and a modified example can be combined as appropriate.

In one embodiment shown in FIG. 1, the hard coating film 1 includes a hard coating layer 3 disposed only on one surface of the transparent substrate 2. However, the arrangement of the hard coat layer 3 is not limited to the above. For example, although not shown, the hard coat layer 3 may be provided on one side and the other side (two main surfaces) of the transparent substrate 2.

In one embodiment shown in FIG. 2, the transparent conductive film 6 includes the hard coat layer 3, the optical adjustment layer 4, and the transparent conductive layer 5 that are arranged only on one side in the thickness direction of the transparent substrate 2, but the hard coat layer 3 The arrangement of the optical adjustment layer 4 and the transparent conductive layer 5 is not limited to the above, for example, a hard coat layer 3 may be provided on one side and the other side of the transparent substrate 2 in the thickness direction in order 、 Optical adjustment layer 4 and transparent conductive layer 5. Examples

Examples and comparative examples are shown below to further illustrate the present invention. Furthermore, the present invention is not limited to any examples and comparative examples. In addition, the specific values such as the blending ratio (ratio), physical property values, and parameters used in the following description can be replaced by the blending ratio (ratio) and physical properties corresponding to those described in the above-mentioned "embodiments". The upper limit (defined as the value of "below" and "not reached") or the lower limit (defined as the value of "above" and "exceeded") described in the values and parameters.

Example 1 As the transparent substrate 2, a COP film (ZEONOR ZF-16, manufactured by ZEON Corporation, Japan) having a thickness of 100 μm was prepared.

Next, using a wire bar applicator #6, the coating liquid (composition) prepared according to the formula described in Table 1 was applied to one side of the transparent substrate 2, and then the solvent was removed by heating at 80°C for 1 minute. After that, it was photo-hardened with a cumulative light amount of 230 mJ/cm ² to form a hard coat layer 3. In addition, each component described in Table 1 is described in Table 2 in detail.

By this, the hard coating film 1 provided with the transparent base material 2 and the hard coating layer 3 is manufactured.

Example 2 to Comparative Example 2 The hard coat layer 3 was formed in the same manner as in Example 1 except that the coating liquid (composition) was changed according to the formula described in Table 1.

<Evaluation> The following items were evaluated, and the results are shown in Table 3.

thickness The thickness of the hard coat layer 3 was measured using MCPD2000 (manufactured by Otsuka Electronics Co., Ltd.).

hardness The hardness of the hard coat layer 3 was measured by the nano-indentation method.

In the nano-indentation method, the nano-indenter (probe, indenter) is pressed against one side of the hard coating 3, and the displacement-load hysteresis curve obtained by this is performed using the software (triboscan) attached to the measurement device Numerical processing, whereby the indentation hardness is obtained.

The nano indenter device and measurement conditions are as follows. Nano indenter device: "Tribo Indenter", manufactured by Hysitron Inc Measurement method: single press method Compression speed: 60 μN/sec Maximum pressing force: 300 μN Maximum pressing time: 2 seconds Probe: triangular cone type (triangular cone type) Temperature: 23℃ Depth of pressing: 1/10 of the thickness of hard coating 3 Pencil hardness The pencil hardness of the hard coat layer 3 was measured according to JIS K5600-5-4 "Scratch Hardness (Pencil Method)" (1999).

Arithmetic mean roughness Ra The arithmetic average roughness Ra of the hard coat layer 3 was measured according to JIS B 0601 (2013).

Anti-blocking The other transparent substrate (ZEONOR ZF-16, manufactured by ZEON Japan) was pressed against the surface of the hard coating layer 3 by finger pressure, and the adhesion of the other transparent substrate to the hard coating layer 3 (anti-sticking) was evaluated as follows Connectivity). ○: The adhesion of another transparent substrate to the hard coat layer 3 did not occur. △: Although another transparent base material is temporarily attached to the hard coat layer 3, it detaches from the hard coat layer 3 after 10 seconds. ×: Another transparent substrate adhered to the hard coat layer 3, and did not detach from the hard coat layer 3 even after 10 seconds.

Haze The haze of the hard coating film 1 (thickness 101 μm) was measured by a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute).

[表2]

[表3]

再者，上述發明雖作為本發明之例示之實施形態提供，但該實施形態僅為例示，並非限定性地解釋。該技術領域之業者所瞭解之本發明之變化例包含於下述專利申請範圍中。Flexural resistance The flexural resistance of the hard coating film 1 was evaluated by a 180-degree bending test. The evaluation criteria are as follows. ○: The hard coating film 1 does not break even when bent at 180 degrees ×: The hard coating film 1 breaks after bending at 180 degrees. The scratch resistance is evaluated by rubbing back and forth 10 times in the thickness direction of the hard coating film 1 with 100 g of steel wool. The scratch resistance of hard coating film 1. The evaluation criteria are as follows. ○: Only less than 10 scratches were observed ×: More than 10 scratches were observed [Table 1]

[Table 2]

[table 3]

In addition, although the above invention is provided as an exemplary embodiment of the present invention, this embodiment is only an example and is not to be interpreted in a limited manner. Variations of the invention known to those skilled in the art are included in the scope of the following patent applications.

1‧‧‧ Hard coating 2‧‧‧Transparent substrate 3‧‧‧hard coating 4‧‧‧Optical adjustment layer 5‧‧‧Transparent conductive layer 6‧‧‧Transparent conductive film

FIG. 1 is a cross-sectional view showing an embodiment of the hard coating film of the present invention. 2 is a cross-sectional view showing a transparent conductive film provided with the hard coating film shown in FIG. 1.

1‧‧‧ Hard coating

2‧‧‧Transparent substrate

3‧‧‧hard coating

Claims (5)

A hard coating film characterized by: With transparent substrate and hard coating in order in the thickness direction, The hard coat layer contains a resin matrix and particles, The hardness of the hard coating layer measured by the nanoindentation method is 0.320 GPa or more and 0.520 GPa or less, The pencil hardness of the above hard coat layer is B or less. The hard coating film according to claim 1, wherein the thickness of the hard coating layer is 3 μm or less. The hard coating film according to claim 1 or 2, wherein the arithmetic average roughness Ra of the above hard coating layer is 3 nm or more and 14 nm or less. The hard coating film according to claim 1 or 2, wherein the material of the transparent substrate is a cycloolefin polymer. A transparent conductive film comprising the hard coating film according to any one of claims 1 to 4 in the thickness direction, an optical adjustment layer, and a transparent conductive layer.

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