JP4574766B2 - Hard coat film and antireflection film - Google Patents

Description

【００５７】
【発明の効果】
本発明によれば、透明基材上に２層以上からなるハードコート層を形成してハードコートフィルムとし、透明基材に最も近く形成されたハードコート層の弾性率を、表層のハードコート層の弾性率よりも高くすることによって、ハードコート層全体の厚みを１０〜５０μｍに厚くしても、従来技術の如きハードコートの割れや剥れ、及びカールを防止しながら、鉛筆硬度４Ｈ以上、且つスクラッチ硬度１５０ｇ以上の優れた硬度を有するハードコートフィルムを提供することができる。
【図面の簡単な説明】
【図１】本発明のハードコートフィルムの基本的な層構成を示す図。
【図２】図１の層構成にプライマー層を付加した構成を示す図。
【図３】防眩性を付与したハードコートフィルムの構成を示す図。
【図４】図１のハードコート層上に反射防止層を設けた構成を示す図。
【図５】スクラッチ硬度の測定に使用したシャープペンシルの仕様を説明する図。
【符号の説明】
１：透明基材
２，２’：ハードコート層
３：接着剤層
４：プライマー層
５：凹凸状
６，６’：反射防止層
ａ：チップ先端径
ｂ：チップ肉厚
ｃ：チップ先端Ｒ
ｄ：チップの長さ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-hardness transparent hard coat film and an antireflection film, and more particularly to a hard coat film and an antireflection film used on the surface of a display such as a CRT, LCD, or PDP.
[0002]
[Prior art]
In recent years, plastic products have been replaced with glass products from the viewpoint of processability and weight reduction, but hard coat films are often used for the purpose of imparting scratch resistance to prevent scratches on the surface. Also, even for conventional glass products, there is an increasing number of cases in which a plastic film is bonded to prevent scattering of glass pieces at the time of breakage, but because the film has insufficient surface hardness, In most cases, a hard coat layer is formed.
[0003]
In recent years, CRT and LCD displays have become widespread, and the number of cases in which a hard coat film is bonded to protect the surface of the displayed image has increased. For the same reason as above, an increase in hardness is required. At the same time, good visibility of the display screen itself via the hard coat film is required. Conventionally, the hard coat layer provided to solve the drawbacks of surface hardness is applied and cured on a base substrate using an ionizing radiation curable resin such as a thermosetting resin or an ultraviolet curable resin. A method of forming one layer of a coating film having a thickness of about 3 to 10 μm is known.
[0004]
However, this film thickness is easily affected by deformation of the base substrate, and the film strength was not sufficiently high. On the other hand, although the deformation of the substrate can be suppressed by increasing the elastic modulus of the hard coat layer, the hard coat layer is liable to crack, and the curl due to curing shrinkage of the hard coat layer increases. At the same time, stress concentrates on the surface of the hard coat layer, so that cracking due to stress strain is likely to occur, and as a result, the film surface is easily scratched. Even if the coating thickness of the hard coat layer is simply increased, the hardness is improved, but cracking, peeling and curling of the hard coat layer cannot be prevented.
[0005]
To solve these problems , Special In Kaihei No. 5-8350, the hard coat layer is divided into two layers, and the hardness of the hard coat layer on the surface layer side is made harder (higher elastic modulus) than that on the substrate side to improve the surface hardness. . When the elastic modulus on the surface layer side is increased in this way, it is certainly possible to prevent damage to a relatively soft material such as a pencil, and to obtain a hardened material.
[0006]
However, when the mechanical pencil base has a high hardness such as a diamond needle, if the elastic modulus of the hard coat layer is too high, the stress is concentrated on the surface and the surface is damaged. In the case of a hard coat film in which an antireflection layer (AR layer) is formed on the hard coat layer of this specification by vapor deposition or sputtering, this phenomenon appears remarkably, and stress is concentrated on the AR layer, resulting in damage. Can be observed visually
[0007]
[Problems to be solved by the invention]
Accordingly, the present invention provides a hard coat film in which a hard coat layer composed of two or more layers is formed on a base material to improve surface hardness, prevent damage to the hard coat film due to stress concentration, and prevent damage to the hard coat film. The purpose is to provide film.
[0008]
[Means for Solving the Problems]
Therefore, in order to solve the above problems, the present invention provides a hard coat film in which a hard coat layer is formed on at least one surface of a transparent substrate, and the hard coat layer is formed in two or more layers. And A hard coat layer is fixed on the plate, and a diamond indenter with a face angle of 136 ° at the tip of the square pyramid is used to gradually load from the hard coat layer surface, and each hard coat is determined from the load when the indentation depth is 1 μm. When the elastic modulus (unit: mN / μm) of the layer was determined, The elastic modulus σm of the hard coat layer formed closest to the transparent substrate is higher than the elastic modulus σs of the surface hard coat layer. And the content of the inorganic fine particles of the hard coat layer formed closest to the transparent substrate is higher than the content of the hard coat layer of the surface layer. A hard coat film is provided.
[0009]
Further, the present invention provides a hard coat film in which an elastic modulus σm of the hard coat layer formed closest to the transparent substrate and an elastic modulus σs of the hard coat layer of the surface layer are 3>σm−σs> 0, A hard coat film having an elastic modulus of 8 mN / μm or more and 13 mN / μm or less of the hard coat layer formed closest to the substrate, and an elastic modulus of the hard coat layer of the surface layer of 6 mN / μm or more and 9 mN / μm or less, Provided is a hard coat film in which the elastic modulus σh of the hard coat film and the elastic modulus σs of the hard coat layer of the surface layer are 2 ≧ σh−σs ≧ 0.
[0010]
Further, the present invention provides a hard coat film having a surface hardness of 4H or more by the pencil hardness method and a scratch hardness of 150 g or more, and a hard coat layer formed at least closest to the transparent substrate. Hard coat fill containing 20 to 80% by mass of inorganic fine particles The provide.
[0011]
Further, the present invention provides a hard coat film in which the inorganic fine particles are silica ultrafine particles having a particle diameter of 100 nm or less, a hard coat layer forming material, a hard coat film mainly comprising an ionizing radiation curable resin, and a thickness of the hard coat layer. However, the hard coat film having a total thickness of 10 μm to 50 μm, the hard coat film having a surface hardness of HB or less by the pencil hardness method, and the transparent substrate having a thickness of 100 μm to 300 μm of polyethylene terephthalate ( A hard coat film that is a film (hereinafter simply referred to as PET) is provided.
[0012]
Furthermore, the present invention provides an antireflection film, wherein the antireflection layer is formed on the hard coat layer of the hard coat film, and the antireflection layer is formed into two or more layers by sputtering or vapor deposition. Among the antireflection films, the antireflection film, wherein the layer in contact with the hard coat layer is composed of ultrafine metal oxide particles.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to preferred embodiments.
The basic layer structure of the hard coat film of the present invention is shown in FIG. In FIG. 1, 1 is a transparent substrate, and 2 and 2 'are two hard coat layers formed of different hard coat layer forming materials.
[0014]
In this example, the hard coat layer is formed of two layers (2, 2 ′), but the hard coat layer may have three or more layers as long as the thickness is 10 μm to 50 μm as a whole. By forming the hard coat layer into two or more layers, it is possible to disperse stress such as bending and impact given from the outside, and there is a problem of cracking and peeling of the thick hard coat layer, and further, a problem of curling. It will be further improved.
[0015]
That is, the hard coat layers 2 and 2 ′ having a thickness of 10 μm to 50 μm are formed on the transparent substrate 1 as a whole, and the hard coat layer 2 contains 20 to 80 mass percent of inorganic fine particles, and the hard coat layer By making the elastic modulus of 2 higher than that of the hard coat layer 2 ′, a hard coat film having an excellent hardness of pencil hardness of 4H or more was realized while preventing cracking, peeling and curling of the hard coat layer. .
[0016]
Here, in the hard coat film of the present invention, the modulus of elasticity σm of the hard coat layer formed closest to the transparent substrate is higher than the modulus of elasticity σ s of the hard coat layer of the surface layer. Characteristics can be obtained. Further, the elastic modulus σm of the hard coat layer formed closest to the transparent substrate and the elastic modulus σs of the hard coat layer of the surface layer are preferably 3>σm−σs> 0, and most preferably 3> σm− σs> 1.
[0017]
As a numerical value of the elastic modulus, the elastic modulus of the hard coat layer formed closest to the transparent substrate is preferably 8 mN / μm or more and 13 mN / μm or less, more preferably 8 mN / μm or more and 12 mN / μm or less, Most preferably, it is 8 mN / μm or more and 10 mN / μm or less. The elastic modulus of the hard coat layer of the surface layer is preferably 6 mN / μm or more and 9 mN / μm or less, more preferably 6.5 mN / μm or more and 9 mN / μm or less, most preferably 7 mN / μm or more and 8.5 mN. / Μm or less. Further, the elastic modulus σh of the hard coat film and the elastic modulus σs of the hard coat layer of the surface layer are preferably 2 ≧ σh−σs ≧ 0, more preferably 1 ≧ σh−σs ≧ 0, most preferably 1>σh−σs> 0.
[0018]
In the present invention, an adhesive layer made of a conventionally known adhesive is used to attach the hard coat film to an object on the opposite side to the hard coat layers 2 and 2 'side of the transparent substrate 1 in the hard coat film. 3 may be provided. Further, as shown in FIG. 2, in order to improve the adhesion between the hard coat layer 2 and the transparent substrate 1, a primer layer 4 having a thickness of about 0.1 μm to 3 μm is used with a conventionally known primer material. May be used.
[0019]
FIG. 3 shows another example of the layer structure of the hard coat film of the present invention, and shows a hard coat film in which the surface of the hard coat layer 2 ′ has an uneven shape 5 to impart antiglare properties. FIG. 4 shows still another layer configuration example of the hard coat film of the present invention. In order to give an antireflection effect to the hard coat film, at least 2 is further provided on the hard coat layer 2 ′ of the hard coat film of FIG. An example of the antireflection hard coat film (antireflection film) provided with the antireflection layers 6 and 6 ′ is shown.
[0020]
The transparent substrate used in the present invention may be any material, but preferably has a pencil hardness of HB or less, more preferably 4B or more and HB or less. As such a transparent substrate, for example, a PET film is suitably used. When visibility of the surface of the object to be stuck to which the hard coat film is stuck is required, a PET film having a thickness of 100 μm to 300 μm is suitable as a transparent substrate.
[0021]
The total thickness of the hard coat layer used in the present invention is 10 to 50 μm, preferably 15 to 50 μm. If the thickness is less than 10 μm, the effect of suppressing the deformation of the transparent substrate by the hard coat layer is small and the hardness is not sufficient, and if the thickness is more than 50 μm, the above-described cracking and peeling, and Any curling is undesirable.
[0022]
Examples of the hard coat layer forming material include ionizing radiation curable resins, thermosetting resins, thermoplastic resins, and engineering plastics. The ionizing radiation curable resin is preferable because the film forming operation can be easily performed on the transparent substrate and the pencil hardness can be easily increased to a desired value.
[0023]
Examples of the ionizing radiation curable resin used for forming the hard coat layer include the following. The ionizing radiation curable resin is preferably one having an acrylate functional group, more preferably a polyester acrylate or a urethane acrylate. The polyester acrylate is composed of a polyester polyol oligomer acrylate or methacrylate (in the present specification, acrylate and / or methacrylate is hereinafter referred to as (meth) acrylate) or a mixture thereof. Further, the urethane (meth) acrylate is constituted by (meth) acrylate of an oligomer composed of a polyol compound and a diisocyanate compound.
[0024]
Monomers constituting (meth) acrylate are methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meth) Examples include acrylate and phenyl (meth) acrylate.
[0025]
Moreover, when giving hardness to a coating film, a polyfunctional monomer can be used together. For example, trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and the like.
[0026]
Polyester oligomers are a condensation of adipic acid and glycol (ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, butylene glycol, polybutylene glycol, etc.) and triol (glycerin, trimethylolpropane, etc.), sebacic acid and glycol or triol. There are polyadipate polyol and polysebacate polyol as products. In addition, some or all of the aliphatic dicarboxylic acids can be replaced with other organic acids. For example, isophthalic acid, terephthalic acid, phthalic anhydride, or the like can be used as a component for imparting excellent hardness to the hard coat layer.
[0027]
The polyurethane-based oligomer can be obtained from an addition product of a polyisocyanate and a polyol. For example, adducts of methylene bis (p-phenylene diisocyanate), hexamethylene diisocyanate hexanetriol, hexamethylene diisocyanate, tolylene diisocyanate, tolylene diisocyanate / trimethylol propane, 1,5-naphthylene diisocyanate, thio Selected from propyl diisocyanate, ethylbenzene-2,4-diisocyanate, 2,4-tolylene diisocyanate dimer, hydrogenated xylylene diisocyanate, tris (4-phenylisocyanate) thiophosphate, and the following polyols: It is obtained by reaction.
[0028]
Examples of polyols include polyether polyols such as polyoxytetramethylene glycol, polyester polyols such as polyadipate polyol and polycarbonate polyol, copolymers of (meth) acrylic acid esters and hydroxyethyl (meth) acrylate, and the like. .
[0029]
Further, when the ionizing radiation curable resin is used as an ultraviolet curable resin, acetophenones, benzophenones, Michler benzoylbenzoate, α-amyloxime esters, thioxanthones, etc. As a photosensitizer, n-butylamine, triethylamine, tri-n-butylphosphine and the like are mixed and used.
[0030]
Urethane (meth) acrylate is rich in elasticity and flexibility and excellent in workability (foldability), but cannot be obtained with a pencil hardness of 2H or higher due to poor surface hardness. On the other hand, polyester (meth) acrylate can provide hardness by selection of the structural component of polyester. To obtain a flexible hard coat film, blending 40 to 10 parts by mass of polyester (meth) acrylate with 60 to 90 parts by mass of urethane (meth) acrylate achieves both high hardness and flexibility. A hard coat film is obtained.
[0031]
And the inorganic fine particle with a particle size of 100 nm or less is added to the coating liquid for forming the hard-coat layer 2 in the ratio of 20-80 mass percentage. By the addition of the inorganic particles, the elastic modulus of the hard coat layer to be formed is improved, and even when the thickness of the hard coat layer is increased, there is an effect of relieving stress at the time of curing the hard coat layer forming material. . If the inorganic fine particles are less than 20% by mass, sufficient cracking prevention, peeling prevention and curl prevention effects cannot be obtained. On the other hand, if the inorganic fine particles exceed 80% by mass, the transparency of the hard coat film obtained is reduced, The flexibility of the coating layer is lowered, and sufficient cracking prevention and peeling prevention effects cannot be obtained as described above. In forming the surface hard coat layer 2 ′, the inorganic fine particles may or may not be contained. However, when it is contained, the content is preferably less than the content of the hard coat layer 2.
[0032]
Silica, magnesium carbonate, aluminum hydroxide, barium sulfate, etc. can be used for the inorganic fine particles. The particle diameter of the preferred inorganic fine particles is 100 nm or less, more preferably 1 nm or more and 100 nm or less, and most preferably 5 nm or more and 30 nm or less. Particularly preferred inorganic fine particles are ultrafine silica particles. These inorganic fine particles are preferred because surface treatment with a silane coupling agent or the like improves dispersibility in the hard coat layer forming material and improves the transparency and strength of the formed hard coat film. The hard coat layers 2 and 2 ′ are coated by roll coating, gravure coating, bar coating, extrusion coating and the like according to the properties of the paint and the coating amount by a conventionally known method. 'Can be formed. The coating is performed in two or more times so that the total dry coating amount is 10 to 50 μm.
[0033]
In the present invention, the hard coat layer is formed in two or more layers using the above materials. As shown in FIG. 1, the hard coat layers 2 and 2 ′ are formed from different hard coat layer forming materials. Even if the resin used is the same system, for example, when the material used is an acrylate material, the acrylic equivalent (average molecular weight / average number of moles of acrylic groups per molecule) is Even if different resin materials and resin materials are the same, if the additives are different, they are different hard coat layer forming materials.
[0034]
Although the thickness of the hard-coat layer 2 is not specifically limited, It is important when suppressing a deformation | transformation of a transparent base material, and it is preferable that it is a thickness of 5 micrometers-45 micrometers. Therefore, the thickness of the hard coat layer 2 ′ is 45 μm to 5 μm. The hard coat layer 2 ′ may also contain inorganic fine particles, but the upper limit thereof is preferably less than 80% by mass and is preferably less than the content of the inorganic fine particles in the hard coat layer 2. If the content of the inorganic fine particles in the hard coat layer 2 ′ is higher than that in the hard coat layer 2, the elastic modulus becomes too high and the surface may become brittle.
[0035]
The elastic modulus of each of the hard coat layers 2 and 2 ′ can be changed depending on the material for forming these layers, the crosslink density, etc., but the crosslink density of the hard coat layer 2 is the same as that of the hard coat layer 2 ′ of the surface layer. It is preferable to make it higher than the crosslinking density. For example, when the hard coat layer forming material is an ionizing radiation curable acrylate monomer or oligomer, the hard coat layer 2 is formed using a material having a small acrylic equivalent, and the hard coat layer 2 ' This can be achieved by using a material having a higher acrylic equivalent.
[0036]
In the present invention, the antireflection film of the present invention is obtained by providing an antireflection layer on the hard coat layer 2 'of the hard coat film obtained as described above. As shown in FIG. 4, the antireflection layer may have a structure of two layers (6, 6 ′) or more. For example, in the case of a two-layer structure, the layer 6 in contact with the hard coat layer is made of a metal having a high refractive index. If the layer is made of ultrafine oxide particles and the surface side layer 6 ′ has a low refractive index, an excellent antireflection effect is exhibited.
[0037]
There are various modes of the antireflection layer as follows, and in the present invention, any structure may be used as long as it is composed of two or more layers using these layers.
(1) MgF with a thickness of about 0.1 μm ₂ A method of using a very thin film such as an antireflection layer.
(2) A method of forming a metal vapor deposition film to form an antireflection layer.
(3) A method of forming an antireflection layer by providing a low refractive index layer made of a material whose light refractive index is lower than that of the hard coat layer.
(4) A method in which a high refractive index layer is in contact with a hard coat layer and a low refractive index layer is provided thereon to form an antireflection layer. For example, an ultrafine particle layer of a metal oxide having a high refractive index may be unevenly distributed at a portion in contact with the hard coat layer 2 ′ in the antireflection layer.
(5) A method in which the layer structure of (4) above is repeatedly laminated to form an antireflection layer.
(6) A method in which a middle refractive index layer, a high refractive index layer and a low refractive index layer are sequentially laminated to form an antireflection layer.
[0038]
【Example】
Next example Reference examples The present invention will be described more specifically with reference to comparative examples.
reference Example 1
An easy-adhesion PET film (U-42: trade name, manufactured by Toray Industries, Inc.) having a thickness of 188 μm was used as a transparent substrate, and an ionizing radiation curable resin (KZ7992, manufactured by JSR Corporation) was used on the PET film having a thickness of 188 μm. (The elastic modulus is 9.2 mN / μm when formed to a thickness of 14 μm on top) is applied to a dry thickness of about 6 μm, and a fusion H bulb is used, and 120 mJ / cm ² The hard coat layer 2 was formed by curing with ultraviolet rays.
[0039]
Next, an ionizing radiation curable resin (EH65, manufactured by The Inktec Co., Ltd .; the elastic modulus when formed on a 188 μm-thick PET film with a thickness of 14 μm) is dried on the hard coat layer 2. The hard coat layer 2 ′ is formed by coating with a thickness of about 8 μm and curing with an electron beam with an acceleration voltage of 175 kV and an irradiation dose of 10 Mrad. Reference example A hard coat film was obtained.
[0040]
Example 2
Using a 188 μm-thick easy-adhesion PET film (U-42: trade name, manufactured by Toray Industries, Inc.) as a transparent substrate, and containing about 40 mass percent of silica ultrafine particles having a particle size of 10 nm to 50 nm that are surface-treated thereon Ionizing radiation curable resin (KZ7992, manufactured by JSR Corporation; the elastic modulus is 11.5 mN / μm when formed on a 188 μm-thick PET film with a thickness of 14 μm) is applied to a dry thickness of about 6 μm. 120mJ / cm using a fusion H valve ² The hard coat layer 2 was formed by curing with ultraviolet rays.
[0041]
Next, an ionizing radiation curable resin (EH65, manufactured by The Inktec Co., Ltd .; the elastic modulus when formed on a 188 μm-thick PET film with a thickness of 14 μm) is dried on the hard coat layer 2. The coating was applied to a thickness of about 8 μm, and cured with an electron beam having an acceleration voltage of 175 kV and an irradiation dose of 10 Mrad to form a hard coat layer 2 ′, thereby obtaining a hard coat film of the present invention.
Example 3
A hard coat film of the present invention was obtained in the same manner as in Example 2 except that the dry thickness of the hard coat layer 2 ′ obtained in Example 2 was about 12 μm.
[0042]
Example 4
The hard coat layer 2 ′ of the hard coat film obtained in Example 2 is made of 27 nm of ITO, SiO 2 as an antireflection layer. ₂ 24 nm, ITO 75 nm and SiO ₂ Was formed to a thickness of 92 nm by a sputtering method to obtain the antireflection film of the present invention.
[0043]
Example 5
On one side of a 50 μm-thick PET film (MC-19: trade name, manufactured by Reiko Co., Ltd.) whose surface was treated with an acrylic melamine resin, ZrO ₂ Fine particle coating solution No. 1275 (ZrO ₂ A coating solution comprising 3 parts by mass of a binder with respect to 15 parts by mass of fine particles: manufactured by Sumitomo Osaka Cement Co., Ltd. was applied to a dry thickness of 57 nm. Furthermore, the ionizing radiation curable resin (EH65, manufactured by The Inktec Co., Ltd.) used in Example 2 as the surface hard coat layer 2 ′ was applied to a dry thickness of about 8 μm and accelerated. Curing was performed with an electron beam having a voltage of 175 kV and an irradiation dose of 10 Mrad.
[0044]
Next, an ultra-fine particle-containing ionizing radiation curable resin (KZ7678, JSR) used in Example 2 as a hard substrate layer 188 μm-thick easy-adhesion PET film (U-42: trade name, manufactured by Toray Industries, Inc.) as a transparent substrate. Co., Ltd.) was applied so that the dry thickness was about 6 μm. Thereafter, the ZrO is applied to the coated surface. ₂ A film on which the fine particle layer and the surface hard coat layer 2 ′ were formed was laminated with the hard coat layer 2 ′ facing each other.
[0045]
Thereafter, the hard coat layer 2 was cured with an electron beam having an acceleration voltage of 175 kV and an irradiation dose of 10 Mrad. By peeling a PET film having a surface thickness of 50 μm from this cured body, ZrO ₂ A hard coat film in which one antireflection layer was formed with fine particles was obtained. Furthermore, as a reflection preventing layer, ITO is formed with 105 nm and SiO. ₂ Was formed to a thickness of 85 nm by a sputtering method to obtain the antireflection film of the present invention.
[0046]
Comparative Example 1
As a transparent base material, an easily adhesive PET film (U-42: trade name, manufactured by Toray Industries, Inc.) having a thickness of 188 μm was used, and an ionizing radiation curable resin (EH65, manufactured by The Inktec Co., Ltd.) was dried thereon. The hard coat film of Comparative Example 1 was obtained by coating with a thickness of about 6 μm and curing with an electron beam having an acceleration voltage of 175 kV and an irradiation dose of 10 Mrad.
[0047]
Comparative Example 2
A hard coat film of Comparative Example 2 was obtained in the same manner as in Comparative Example 1 except that the dry thickness of the hard coat layer in Comparative Example 1 was about 14 μm.
Comparative Example 3
A hard coat film of Comparative Example 3 was obtained in the same manner as in Comparative Example 1 except that the dry thickness of the hard coat layer in Comparative Example 1 was about 20 μm.
[0048]
Comparative Example 4
Uses 188 μm-thick easy-adhesion PET film (U-42: trade name, manufactured by Toray Industries, Inc.) as a transparent substrate, and contains about 40% by mass of silica ultrafine particles having a particle size of 10 nm to 50 nm that are surface-treated thereon. Hard coating of Comparative Example 4 by applying an ionizing radiation curable resin (KZ7978, manufactured by JSR Corporation) to a dry thickness of about 6 μm and curing it with an electron beam with an acceleration voltage of 175 kV and an irradiation dose of 10 Mrad A film was obtained.
[0049]
Comparative Example 5
A hard coat film of Comparative Example 5 was obtained in the same manner as in Comparative Example 4 except that the dry thickness of the hard coat layer in Comparative Example 4 was about 14 μm.
Comparative Example 6
As a transparent base material, an easily adhesive PET film (U-42: trade name, manufactured by Toray Industries, Inc.) having a thickness of 188 μm was used, and an ionizing radiation curable resin (EH65, manufactured by The Inktec Co., Ltd.) was dried thereon. Coating to a thickness of about 8μm, using a fusion H bulb, 120mJ / cm ² The hard coat layer 2 was formed by curing with ultraviolet rays.
[0050]
Next, an ionizing radiation curable resin (KZ7978, manufactured by JSR Corporation) containing about 40% by mass of surface-treated ultrafine silica particles having a particle size of 10 nm to 50 nm on the hard coat layer 2 has a dry thickness of about 6 μm. The hard coat layer 2 ′ was formed by curing with an electron beam having an acceleration voltage of 175 kV and an irradiation dose of 10 Mrad, and a hard coat film of Comparative Example 6 was obtained.
[0051]
Comparative Example 7
The hard coat layer 2 ′ of the hard coat film obtained in Comparative Example 6 was coated with 27 nm ITO as an antireflection layer, SiO ₂ 24 nm, ITO 75 nm and SiO ₂ Was formed to a thickness of 92 nm by a sputtering method to obtain an antireflection film of Comparative Example 7.
[0052]
Each of the above embodiments Reference examples The following various measurements were performed on each hard coat film or hard coat layer in Comparative Examples, and the results are shown in Table 1 below.
Measurement of elastic modulus:
A resin film on which a hard coat layer is formed (for example, a PET film having a thickness of 188 μm) is fixed on a glass plate with an adhesive, and gradually from the surface of the hard coat layer by a diamond indenter having a facing angle of 136 ° at the tip of a quadrangular pyramid. The elastic modulus (unit: mN / μm) is obtained from the load when the indentation depth becomes 1 μm, and is used as the elastic modulus of the hard coat layer. Actual measurement was performed for the hard coat layer on the surface layer, the hard coat layer closest to the substrate, and the hard coat film.
[0053]
Pencil hardness measurement:
Perform in accordance with JIS K-5400. This measurement shows the hardness of the hard coat film by the hardness of the pencil used when scratching 5 times and no appearance abnormality such as scratches 2 times or more was observed. For example, the measurement is performed 5 times using a 4H pencil, and if the appearance abnormality does not occur twice or more, the pencil hardness of the hard coat film is displayed as 4H.
[0054]
Scratch hardness measurement:
By tilting the tip of the mechanical pencil having the specifications shown in FIG. 5 at 45 °, the curved surface portion (c) of the tip is brought into contact with the film as the object to be measured, and 6.35 mm / sec while applying a load. Scratch the surface of the hard coat film at a speed of. The load is changed in increments of 10 g, the determination is made visually, and the maximum load value at which no abnormal appearance is found is taken as the scratch hardness of the hard coat film. In FIG. 5, the specifications of the mechanical pencil are as follows.
Model number Pentel PD-355 or equivalent
Tip tip diameter a = 0.9 ± 0.06mm
Chip thickness b = 0.2mm
Tip tip Rc ≦ 0.15mm
Chip length d ≦ 3.0mm
Chip hardness 200 ± 20Hv
[0055]
Measurement of curl:
Place the A4 size hard coat film so that the hard coat surface is in close contact with the installation surface, leave it for 24 hours in an environment of 23 ± 2 ° C, 50 ± 5% RH, and set the four corners of the hard coat film. The distance of lifting from the surface was measured, and the maximum value was evaluated. If less than 15 mm, it was evaluated as ◯ if it was 15-30 mm, and x if it was more than 30 mm.
Evaluation of adhesion:
l. A 5 mm square cross-hatch test was performed twice on the hard coat film, and the number of hard coat layers that did not peel from the substrate was displayed.
[0056]
[Table 1]

[0057]
【The invention's effect】
According to the present invention, a hard coat layer composed of two or more layers is formed on a transparent substrate to form a hard coat film, and the elastic modulus of the hard coat layer formed closest to the transparent substrate is determined as the surface hard coat layer. Even when the thickness of the entire hard coat layer is increased to 10 to 50 μm by making the elastic modulus higher than the above, the pencil hardness of 4H or more is prevented while preventing cracking, peeling, and curling of the hard coat as in the prior art. And the hard coat film which has the outstanding hardness of 150 g or more of scratch hardness can be provided.
[Brief description of the drawings]
FIG. 1 is a view showing a basic layer structure of a hard coat film of the present invention.
FIG. 2 is a diagram showing a configuration in which a primer layer is added to the layer configuration of FIG.
FIG. 3 is a diagram showing a configuration of a hard coat film imparted with antiglare properties.
4 is a view showing a configuration in which an antireflection layer is provided on the hard coat layer of FIG. 1;
FIG. 5 is a diagram for explaining the specifications of a mechanical pencil used for measurement of scratch hardness.
[Explanation of symbols]
1: Transparent substrate
2, 2 ': Hard coat layer
3: Adhesive layer
4: Primer layer
5: Concavity and convexity
6, 6 ': Antireflection layer
a: Tip tip diameter
b: Chip thickness
c: Tip tip R
d: Length of chip

Claims (14)

A hard coat film having a hard coat layer formed on at least one surface of a transparent substrate, wherein the hard coat layer is formed in two or more layers, and the hard coat layer is fixed on a plate, A diamond indenter with a face angle of 136 ° at the tip of the pyramid is gradually loaded from the surface of the hard coat layer, and the elastic modulus of each hard coat layer (unit: mN / μm) from the load when the indentation depth becomes 1 μm when asked for, modulus σm of the hard coat layer which is closest formed on the transparent substrate, rather higher than the elastic modulus σs of the surface layer of the hard coat layer, and, formed closest to said transparent substrate hard coat film content of inorganic fine particles of the hard coat layer, than the content of the surface layer of the hard coat layer and wherein the high Ikoto. The elastic modulus σm (unit: mN / μm) of the hard coat layer formed closest to the transparent substrate and the elastic modulus σs (unit: mN / μm) of the hard coat layer of the surface layer are 3>σm−σs> 0 The hard coat film according to claim 1.   The elastic modulus of the hard coat layer formed closest to the transparent substrate is 8 mN / μm or more and 13 mN / μm or less, and the elastic modulus of the hard coat layer of the surface layer is 6 mN / μm or more and 9 mN / μm or less. The hard coat film according to 1 or 2. Modulus .SIGMA.H (Unit: mN / μm) of the hard coat film and the surface layer of the hard coat layer modulus [sigma] s (Unit: mN / [mu] m) any of claims 1 to 3 is 2 ≧ σh-σs ≧ 0 2. The hard coat film according to item 1.   The hard coat film according to any one of claims 1 to 4, wherein the hard coat film has a surface hardness of 4H or more in terms of pencil hardness and a scratch hardness of 150 g or more.   The hard coat film according to any one of claims 1 to 5, wherein the hard coat layer formed at least closest to the transparent substrate contains 20 to 80% by mass of inorganic fine particles. The hard coat film according to claim 6, wherein the inorganic fine particles are ultrafine silica particles having a particle diameter of 100 nm or less. The hard coat film according to any one of claims 1 to 7 , wherein the hard coat layer forming material mainly comprises an ionizing radiation curable resin. The hard coat film according to any one of claims 1 to 8 , wherein the hard coat layer has a total thickness of 10 µm to 50 µm. The hard coat film according to any one of claims 1 to 9 , wherein the surface hardness of the transparent substrate is HB or less by a pencil hardness method. The hard coat film according to any one of the transparent substrate, according to claim 1 to 1 0 is a polyethylene terephthalate film having a thickness of 100 m to 300 m. An antireflection film, wherein an antireflection layer is formed on the hard coat layer of the hard coat film according to any one of claims 1 to 11. The antireflection film as described the antireflection layer to claim 1 2, which is formed of two or more layers by sputtering or vapor deposition. Among the anti-reflection layer, the layer in contact with the hard coat layer, an antireflection film according to claims 1 to 3, is composed of ultrafine particles of metal oxides.

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