JP2019215408A - Hard coat film and transparent conductive film - Google Patents

Abstract

To provide a hard coat film has both excellent flex resistance and scratch resistance and excellent flexibility, and a transparent conductive film including the same.SOLUTION: A hard coat film 1 comprises a transparent base material 2 and a hard coat layer 3 in order in a thickness direction. The hard coat layer 3 includes a resin matrix and particles. The hardness of the hard coat layer 3 measured by a nano-indentation method is 0.320 GPa or more and 0.520 GPa or less. The pencil hardness of the hard coat layer 3 is B or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hard coat film and a transparent conductive film, and more particularly, to a hard coat film and a transparent conductive film including the same.

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

  For example, a hard coat film including a hard coat layer having an elastic modulus of 2.1 to 5.0 GPa has been proposed (for example, see Patent Document 1).

  JP 201425061A

  However, the hard coat layer is required to have excellent bending resistance. However, in the hard coat film described in Patent Document 1, the elastic modulus of the hard coat layer is as high as 2.1 to 5.0 GPa. The demand cannot be fully satisfied.

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

  Further, the hard coat film is required to be flexible while having excellent bending resistance and scratch resistance.

  The present invention provides a hard coat film having both excellent bending resistance and abrasion resistance and excellent flexibility, and a transparent conductive film including the same.

  The present invention (1) comprises a transparent base material and a hard coat layer in the thickness direction in order, the hard coat layer includes a resin matrix and particles, and the hardness of the hard coat layer measured by a nanoindentation method. A hard coat film having 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.

  The present invention (2) includes the hard coat film according to (1), wherein the thickness of the hard coat layer is 3 μm or less.

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

  The present invention (4) includes the hard coat 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 coat film according to any one of (1) to (4), an optical adjustment layer, and a transparent conductive layer in the thickness direction.

  In the hard coat film and the transparent conductive film of the present invention, the hardness of the hard coat layer 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. It has both flexibility and abrasion resistance and excellent flexibility.

FIG. 1 shows a cross-sectional view of one embodiment of the hard coat film of the present invention. FIG. 2 is a sectional view of a transparent conductive film provided with the hard coat film shown in FIG.

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

  The hard coat film 1 has one surface and the other surface (two main surfaces) that face each other at an interval in the thickness direction. One surface and the other surface of the hard coat film 1 are flat surfaces parallel to each other. The hard coat film 1 has a substantially film shape extending in a plane direction orthogonal to the thickness direction.

  The hard coat film 1 is, for example, one component provided in a transparent conductive film 6 (see FIG. 2) described later, that is, is not the transparent conductive film 6. That is, the hard coat film 1 is a component for producing the transparent conductive film 6, does not include the optical adjustment layer 4 and the transparent conductive layer 5, and is a device which is distributed as a component alone and industrially usable.

  The hard coat film 1 includes a transparent substrate 2 and a hard coat layer 3 in order toward one side in the thickness direction. That is, the hard coat film 1 includes the transparent substrate 2 and the hard coat layer 3 disposed on one surface in the thickness direction of the transparent substrate 2. Further, preferably, the hard coat film 1 is composed of only the transparent base material 2 and the hard coat layer 3.

  The transparent substrate 2 forms the other surface of the hard coat film 1. Specifically, the transparent base material 2 is a support material for securing the mechanical strength of the hard coat film 1. The transparent substrate 2 has a film shape extending in the plane direction. The transparent substrate 2 has one surface and the other surface that are arranged to face each other at an interval in the thickness direction. One surface and the other surface of the transparent substrate 2 are flat surfaces parallel to each other. The other surface in the thickness direction of the transparent substrate 2 is exposed to 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 a resin (including a polymer). Examples of the resin include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; for example, (meth) acrylic resins such as polymethacrylate (acrylic resin and / or methacrylic resin); for example, polyethylene, polypropylene, and cycloolefin Olefin resin such as polymer (COP), for example, polycarbonate resin, for example, polyether sulfone resin, for example, polyarylate resin, for example, melamine resin, for example, polyamide resin, for example, polyimide resin, for example, cellulose resin, for example, polystyrene Resins, for example, norbornene resins and the like. These resins can be used alone or in combination of two or more. From the viewpoint of securing excellent optical characteristics (including transparency), preferably, an olefin resin is used, and more preferably, COP is used.

  COP is superior in optical characteristics (isotropic) as compared with polyester resin. On the other hand, COP has lower mechanical strength (easy to crack) than polyester resin. However, since the hard coat film 1 includes the hard coat layer 3 having desired hardness and pencil hardness, even if the mechanical strength of the transparent substrate 2 is low, the hard coat film 1 has a large decrease in mechanical strength. (Cracking) can be suppressed.

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

  The thickness of the transparent substrate 2 is a length between one surface and the other surface (the same applies to each of the following layers), specifically, for example, 2 μm or more, preferably 20 μm or more. It is 300 μm or less, preferably 200 μm or less.

  The hard coat layer 3 forms one surface of the hard coat film 1. Specifically, the hard coat layer 3 is a hard layer that secures excellent scratch resistance while imparting excellent flex resistance to the hard coat film 1. Further, the hard coat layer 3 is also an anti-blocking layer that provides the hard coat film 1 with blocking resistance. 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 which are opposed to each other at an interval 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, for example, exposed on one side in the thickness direction of the hard coat film 1 and has a fine uneven shape (not shown in FIG. 1).

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

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

  The material of the particles is not particularly limited, and is not particularly limited as long as it is transparent, and examples thereof include an organic material and an inorganic material. Examples of the organic material include polymers such as an acrylic polymer and polystyrene, and preferably include an acrylic polymer. Examples of the inorganic material include metal oxides composed of silica, for example, zirconium oxide, titanium oxide, zinc oxide, tin oxide, and the like, for example, carbonates such as calcium carbonate. Preferably, silica 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 irregular shape, and preferably a substantially spherical shape.

  The average value of the maximum length of the particles (the average particle diameter in the case of a substantially spherical shape) is preferably relatively small, and more preferably nano-sized. 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 Is 10 nm or more.

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

  When the average value of the maximum length of the particles is equal to or more than the above lower limit, excellent antiblocking properties can be imparted to the hard coat film 1.

  The hard coat layer 3 is formed from the above-described composition, and a resin matrix and particles dispersed therein are provided in the hard coat layer 3.

  The number of parts by mass of the particles is, for example, 0.1 part 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 with respect to 100 parts by mass of the resin. is there.

  Hard coat layer 3 has a hardness of 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 coat layer 3 is lower than the lower limit described above, the hard coat film 1 cannot secure 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, still more preferably 0.400 GPa or less, and particularly preferably 0.370 GPa or less. It is. If the hardness of the hard coat layer 3 exceeds the upper limit described above, the hard coat film 1 cannot secure excellent flex resistance.

  The hardness of the hard coat layer 3 is an indentation hardness of 23 ° C. measured by a nanoindentation method, and specifically, is obtained by pushing a nano indenter (indenter) into the hard coat layer 3 at 23 ° C. Indentation hardness. The details of the method for measuring the hardness will be described in Examples below.

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

  If the pencil hardness of the hard coat layer 3 exceeds the above upper limit (B) (exceeds B), excellent flexibility of the hard coat layer 3 cannot be secured.

  The pencil hardness of the hard coat layer 3 is measured according to JIS K5600-5-4 "Scratch hardness (pencil method)" (1999).

  Arithmetic average roughness Ra of one surface of 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 Is 12 nm or less.

  If the arithmetic average roughness Ra of one surface of the hard coat layer 3 is equal to or more than the lower limit, excellent anti-blocking properties can be imparted to the hard coat film 1.

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

  The arithmetic average roughness Ra of the hard coat layer 3 is measured according to JIS B0601 (2013).

  The hard coat layer 3 is preferably relatively 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, further preferably 5 μm or less, particularly preferably 3 μm or less, and most preferably 2 μm or less. It is as follows. When the thickness of the hard coat layer 3 is equal to or less than the above 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 further preferably 0.5 μm or more. When the thickness of the hard coat layer 3 is at least the lower limit described above, the scratch resistance of the hard coat layer 3 can be improved.

  The thickness of the hard coat layer 3 is measured using an instantaneous multi-photometry system “MCPD2000” (trade name) manufactured by Otsuka Electronics Co., Ltd.

  The haze of the hard coat film 1 is, for example, less than 0.5, preferably 0.40 or less, more preferably 0.30 or less, further preferably 0.20 or less, particularly preferably 0.20 or less in the case of a thickness of 101 μm. , 0.15 or less, and usually 0.01 or more.

  If the haze of the hard coat film 1 is less than the above-mentioned upper limit, the hard coat film 1 will be excellent in transparency.

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

  In order to manufacture the hard coat film 1, for example, first, a transparent substrate 2 is prepared, 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 solution (varnish) prepared by diluting the composition with a solvent is prepared. A mixture (commercially available) in which particles are dispersed in a resin in advance can be prepared (prepared) as it is as a coating solution, or it can be prepared by mixing particles and a resin and dispersing the particles in the resin. it can. In addition, an initiator can be added to the coating liquid, if necessary, or a resin to which an initiator has been added in advance can be used.

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

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

  Thus, the hard coat film 1 including the transparent substrate 2 and the hard coat layer 3 is manufactured.

  The hard coat film 1 is used for various industrial uses, for example, for optical uses such as a transparent conductive film and a light control film, and further for electromagnetic shielding. Preferably, it is used for optical applications, and more preferably for transparent conductive films.

  Next, the transparent conductive film 6 including the hard coat film 1 will be described with reference to FIG.

  The transparent conductive film 6 has one surface and the other surface (two main surfaces) that face each other at an interval in the thickness direction. One surface and the other surface of the transparent conductive film 6 are flat surfaces 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, one component such as a base material for a touch panel or a light control panel provided in an optical device (for example, an image display device or a light control device), that is, it is not an optical device. That is, the transparent conductive film 6 is a component for producing an optical device or the like, does not include an image display element such as an LCD module, or a light source such as an LED, is distributed as a component alone, and is an industrially usable device. It is.

  The transparent conductive film 6 includes the hard coat film 1, the optical adjustment layer 4, and the transparent conductive layer 5 sequentially in the thickness direction. Specifically, the transparent conductive film 6 includes the transparent base material 2, the hard coat layer 3, the optical adjustment layer 4, and the transparent conductive layer 5 sequentially in the thickness direction. Preferably, the transparent conductive film 6 includes only the transparent base material 2, the hard coat layer 3, the optical adjustment layer 4, and the transparent conductive layer 5.

  After the transparent conductive layer 5 is formed on the wiring pattern in a later step, the optical adjustment layer 4 is formed so that the difference between the non-pattern part and the pattern part is not recognized (that is, the visual recognition of the wiring pattern is suppressed). And a layer (index matching layer) for adjusting the optical properties of the transparent conductive film 6. The optical adjustment layer 4 has a film shape extending in the plane direction, and has one surface and the other surface that are opposed to each other at an interval in the thickness direction. Examples of the material of the optical adjustment layer 4 include the above-described resin (containing no particles) and the above-described composition (containing 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 in a later step to form a pattern portion. The transparent conductive layer 5 forms one 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 surface direction, and has one surface and the other surface arranged to face each other at an interval in the thickness direction.

  As the material of the transparent conductive layer 5, for example, at least one selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W Metal oxide containing the metal of the formula The metal oxide can be further doped with a metal atom shown in the above group, if necessary. Preferably, the material includes indium tin composite oxide (ITO), antimony tin composite oxide (ATO), and the like.

  The thickness of the transparent conductive layer 5 is, for example, 10 nm or more, preferably 20 nm or more, and is, 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 is, 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 in the thickness direction of the hard coat layer 3 of the hard coat film 1 by a known method.

  In the hard coat film 1 and the transparent conductive film 6, the hardness of the hard coat layer 3 is 0.320 GPa or more, so that excellent scratch resistance can be secured.

  Further, since the hardness of the hard coat layer 3 is 0.520 GPa or less, excellent bending resistance can be secured.

  Furthermore, since the pencil hardness of the hard coat layer 3 is B or less, flexibility can be secured while having excellent bending resistance and scratch resistance.

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

  When the arithmetic average roughness Ra of the hard coat layer 3 is 3 nm or more and 14 nm or less, excellent anti-blocking properties can be imparted to the hard coat film 1 while ensuring excellent transparency of the hard coat film 1. be able to.

  When the material of the transparent substrate 2 is COP, the transparent substrate 2 has excellent optical properties, but has low mechanical strength (easy to be cracked). Since the hard coat layer 3 having hardness is provided, it is possible to suppress a large decrease in the mechanical strength of the hard coat layer 3 (the occurrence of cracks) in the hard coat film 1.

Modified Examples In the following modified examples, the same members and steps as those of the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In addition, each modified example can achieve the same operation and effect as those of the embodiment except for special mention. Further, one embodiment and a modified example can be appropriately combined.

  In one embodiment shown in FIG. 1, the hard coat film 1 includes a hard coat layer 3 disposed on only 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 includes the hard coat layer 3 disposed on both one surface and the other surface (two main surfaces) of the transparent substrate 2. You can also.

  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 disposed only on one side in the thickness direction of the transparent substrate 2. The arrangement of the layer 3, the optical adjustment layer 4, and the transparent conductive layer 5 is not limited to the above. For example, the hard coat layer 3 and the optical An adjustment layer 4 and a transparent conductive layer 5 can also be provided.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. In addition, this invention is not limited to an Example and a comparative example at all. Specific numerical values such as the mixing ratio (ratio), physical property values, and parameters used in the following description are the mixing ratios (ratio) corresponding to those described in the above “Embodiment of the Invention”. ), Physical properties, parameters, etc., can be replaced by the upper limit (numerical values defined as “less than” or “less than”) or the lower limit (numerical values defined as “more than” or “exceeding”).

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

Subsequently, a coating solution (composition) prepared according to the formulation shown in Table 1 was applied to one surface of the transparent substrate 2 using a wire bar # 6, and then the solvent was heated at 80 ° C. for 1 minute. After the removal, photo-curing was performed with an integrated light amount of 230 mJ / cm ² to form a hard coat layer 3. In addition, the details of each component described in Table 1 are described in Table 2.

  Thus, a hard coat film 1 including the transparent substrate 2 and the hard coat layer 3 was 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 solution (composition) was changed according to the formulation shown 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 a nanoindentation method.

  In the nanoindentation method, a nanoindenter (probe, indenter) is pushed into one surface of the hard coat layer 3, and a displacement-load hysteresis curve obtained by this is numerically processed by software (triboscan) attached to the measuring device. To obtain indentation hardness.

The nano indenter device and measurement conditions are as follows.
Nano indenter device: "Tribo Indenter", manufactured by Hysitron Inc. Measurement method: Single indentation method Indentation speed: 60 μN / sec Maximum indentation force: 300 μN
Maximum pushing force holding time: 2 seconds Tip: triangular pyramid type (Birkovich type)
Temperature: 23 ° C
Indentation depth: 1/10 of the thickness of the hard coat layer 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 B0601 (2013).

Anti-blocking property Another transparent substrate (ZEONOR ZF-16, manufactured by Zeon Corporation) is pressed on the surface of the hard coat layer 3 by finger pressure, and another transparent substrate is stuck to the hard coat layer 3 (anti-blocking property). Was evaluated as follows.
：: No sticking of another transparent substrate to the hard coat layer 3 occurred.
Δ: Another transparent substrate once adhered to the hard coat layer 3, but separated from the hard coat layer 3 after 10 seconds.
×: Another transparent substrate was stuck to the hard coat layer 3 and did not separate from the hard coat layer 3 even after 10 seconds.

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

Flex resistance The flex resistance of the hard coat film 1 was evaluated by a 180-degree bending test. The evaluation criteria are as follows.
：: Hard coat film 1 was not broken even when bent at 180 degrees. X: Hard coat film 1 was broken when bent at 180 degrees. Scratch resistance One side in the thickness direction of hard coat film 1 was reciprocated 10 times with 100 g of steel wool. The abrasion resistance of the hard coat film 1 was evaluated by rubbing.
The evaluation criteria are as follows.
：: Less than 10 scratches observed ×: 10 or more scratches observed

DESCRIPTION OF SYMBOLS 1 Hard-coat film 2 Transparent base material 3 Hard-coat layer 4 Optical adjustment layer 5 Transparent conductive layer 6 Transparent conductive film

Claims (5)

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

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