JP7013680B2 - Hardcourt film, ionizing radiation curable resin composition, and display - Google Patents

Description

The present invention relates to a hard coat film having a hard coat layer on a substrate, an ionizing radiation curable resin composition forming the hard coat layer, and a display provided with the hard coat film.

The image display surface of an image display device such as a liquid crystal display, a CRT display, a projection display, a plasma display, an electroluminescence display, and a touch panel display is required to have scratch resistance so as not to be scratched during handling. In response to such a demand, it is generally practiced to improve the scratch resistance of the image display surface of the image display device by using a hard coat film having a hard coat layer provided on the substrate.

For example, Patent Document 1 describes an infrared spectroscopic peak area P1 of a carbon-carbon double bond of a hard coat layer formed on one surface of a transparent substrate and an infrared spectroscopic spectrum of a carbon-oxygen double bond. A hard coat film in which the ratio of the peak area P2 (P1 / P2) is within a specific range is disclosed. Further, Patent Document 2 discloses a laminate for forming a hard coat, which is formed by laminating a curable composition layer formed by using a curable composition having inorganic oxide particles added to at least one surface of a plastic film. Has been done.

Japanese Unexamined Patent Publication No. 2015-69071 Japanese Unexamined Patent Publication No. 2012-148484

The hard-coated film is required to have excellent stability during its manufacturing process. Further, when it is used in an image display device or the like, it is required to have excellent workability because it is subjected to processing such as punching, router processing, cutting processing, cutting processing, and bending processing.
Further, in recent years, the development of a flexible display capable of bending has been active, and the hard coat film installed on the surface of the flexible display is also required to have excellent flexibility.

On the other hand, in the examples of Patent Document 1, although the hard coat layer containing no metal oxide particles has been measured for ultrafine indentation hardness and evaluated for pencil hardness, there is no description or evaluation regarding flexibility. Further, as a result of confirmation by the present inventors, it was found that the hard-coated film of Patent Document 1 does not have both hardness and flexibility.
Further, in a conventional hard coat film as in Patent Document 2, although the hardness can be improved by adding inorganic oxide particles, the flexibility is not sufficient and cracks may occur during processing. be. Further, if a large amount of inorganic oxide particles are added in order to increase the hardness, the dispersibility of the inorganic oxide particles deteriorates, and the hardness may rather decrease.

The present invention has been made in view of such circumstances, and is a hard coat film having high hardness and excellent flexibility, and an ionizing radiation curable resin composition forming a hard coat layer of the hard coat film. , And a display provided with the hardcourt film.

As a result of diligent studies to solve the above problems, the present inventors have determined to solve the above problems by containing a binder resin having an oxyethylene structure and metal oxide particles in the hard coat layer. I found it.
The present invention has been completed based on such findings.

That is, the present invention provides the following [1] to [3].
[1] A hard coat film having a hard coat layer on a substrate, wherein the hard coat layer contains a binder resin having an oxyethylene structure and metal oxide particles, and a Vickers indenter is pushed into the hard coat layer. The indentation hardness (HIT) measured thereby is 600 N / mm ² or more when the maximum indentation depth of the Vickers indenter is 500 nm, and conforms to JIS-K5600-5-1 (1999). A hard coat film having a minimum diameter of 20 mm or less in a bending resistance test measured by the cylindrical mandrel method.
[2] A display having a curved structure or foldable with the hard-coated film according to the above [1].
[3] It contains (A) an ionizing radiation curable resin and (B) metal oxide particles, and the component (A) has (i) an oxyethylene group and a (meth) acryloyl group content of 6. The (meth) acryloyl group in the total amount of the (A) component, which contains a polyfunctional (meth) acrylate compound having a concentration of 0.0 mmol / g or more and (ii) a polyfunctional (meth) acrylate compound having no oxyethylene group. An ionizing radiation curable resin composition having a total amount of 3.0 to 6.5 mmol / g and a content of oxyethylene groups contained in the total solid content of 0.5 to 14% by mass.

According to the present invention, a hard coat film having high hardness and excellent flexibility, an ionizing radiation curable resin composition forming a hard coat layer of the hard coat film, and a display provided with the hard coat film. Can be provided.

It is a schematic diagram which shows one form of the cross section of the hard coat film of this invention. 6 is an SEM photograph of a cross section of the hard coat film obtained in Example 1 taken with a scanning electron microscope. 6 is an SEM photograph of a cross section of the hard coat film obtained in Comparative Example 1 taken with a scanning electron microscope. 4 (a) and 4 (b) are diagrams for explaining a method of measuring the indentation hardness (HIT) of a hard-coated film.

<Hardcourt film>
The hard coat film of the present invention has a binder resin having an oxyethylene structure and a hard coat layer containing metal oxide particles on a base material.
Here, in the present invention, "having an oxyethylene structure" means having a group containing an oxyethylene bond ( _-CH2 - _CH2 -O-).
Further, in the hard coat film of the present invention, the indentation hardness (HIT) measured by pushing the Vickers indenter into the hard coat layer is 600 N / mm ² when the maximum pushing depth of the Vickers indenter is 500 nm. In addition, in the bending resistance test measured by the cylindrical mandrel method according to JIS-K5600-5-1 (1999), the minimum diameter of the mandrel is 20 mm or less.

FIG. 1 is a schematic view showing one form of a cross section of the hard coat film of the present invention. In the schematic diagram shown in FIG. 1, for the sake of facilitation of explanation, the scale in the thickness direction (vertical direction in the figure) is greatly enlarged and exaggerated from the scale in the width direction (horizontal direction in the figure). be. The hard coat film 10 is provided with a hard coat layer 2 on the base material 1.

FIG. 2 is an SEM photograph of a cross section of the hard coat film obtained in Example 1 taken with a scanning electron microscope. In the SEM photograph, the silica particles (metal oxide particles) contained in the hard coat layer are uniformly dispersed, and the silica particles existing at a depth of 1.5 μm (l ₁ ) from the surface of the hard coat layer and the base. No bias is observed between the silica particles existing at a height of 1 μm (l ₂ ) from the interface between the material and the hard coat layer.
It is considered that this is because the hard coat layer contains the binder resin having an oxyethylene structure, so that the dispersibility of the silica particles contained in the hard coat layer is improved. As a result, the hardness of the hard coat layer is increased, and excellent flexibility is imparted to the hard coat layer.

FIG. 3 is an SEM photograph of a cross section of the hard coat film obtained in Comparative Example 1 taken with a scanning electron microscope. In the SEM photograph, the silica particles existing at a depth of 1.5 μm (l ₁ ) from the surface of the hard coat layer are sparse, whereas the silica particles are sparse at a height of 1 μm (l ₂ ) from the interface between the substrate and the hard coat layer. The silica particles present are dense. As described above, when the binder resin contained in the hard coat layer does not have an oxyethylene structure, silica particles are unevenly distributed in the vicinity of the interface of the hard coat layer with the base material, and the rigidity of the hard coat layer is increased in the vicinity of the interface. It will be higher and cracks will be more likely to occur.

The hard coat film of the present invention has an indentation hardness (HIT) measured by pushing a Vickers indenter into a hard coat layer at 600 N / mm ² or more when the maximum indentation depth of the Vickers indenter is 500 nm. Yes, preferably 650 N / mm ² or more, more preferably 700 N / mm ² or more. If it is less than 600 N / mm ² , the hardness of the hard coat film surface becomes insufficient, and the scratch resistance may not be sufficiently exhibited.

An example of the method for measuring the indentation hardness (HIT) will be described with reference to FIGS. 4 (a) and 4 (b).
As shown in FIG. 4 (a), a hard coat film 20 provided with a hard coat layer 12 is prepared on the base material 11. Further, a Vickers indenter 30 for pushing against the surface 12a on the hard coat layer 12 side of the hard coat film 20 is prepared.

Next, as shown in FIG. 4 (b), the Vickers indenter 30 is pushed into the surface 12a on the hard coat layer 12 side of the hard coat film 20. At this time, the indentation hardness (HIT) of the surface 12a of the hard coat film 20 can be calculated by measuring the load F _max required to make the maximum indentation depth h _max of the Vickers indenter 30 to 500 nm. can. For example, the indentation hardness (HIT) (N / mm ² ) is calculated by the following formula (I).

ここで、式（Ｉ）中、Ｆ_ｍａｘは最大試験荷重（Ｎ）、Ａ_ｐは接触投影面積（ｍｍ^２）である。また、ｈ_ｒはナノインデンテーションから得られる荷重―変位曲線において、除荷曲線の接線より得られる深さ（mm）、εは圧子の幾何学形状による補正係数である。
なお、上記インデンテーション硬さ（ＨＩＴ）の測定は、例えば、（株）フィッシャー・インスツルメント製、ピコデンターＨＭ－５００を用いて測定することができる。

Here, in the formula (I), F _max is the maximum test load (N), and _Ap is the contact projection area (mm ² ). Further, hr is the depth (mm) obtained from the tangent of the unloading curve in the load-displacement curve obtained from the _{nanoindentation} , and ε is the correction coefficient due to the geometric shape of the indenter.
The indentation hardness (HIT) can be measured by using, for example, Picodenter HM-500 manufactured by Fisher Instruments Co., Ltd.

The hard-coated film of the present invention has a minimum diameter of 20 mm or less, preferably 18 mm or less, more preferably 18 mm or less in a bending resistance test measured by a cylindrical mandrel method based on JIS-K5600-5-1 (1999). Is 16 mm or less. If it exceeds 20 mm, the flexibility of the hard coat film becomes insufficient, and cracks may easily occur.

Hereinafter, embodiments of each layer constituting the hard-coated film of the present invention will be described.
(Base material)
The base material used for the hard coat film of the present invention is preferably one having light transmittance, smoothness, heat resistance, and excellent mechanical strength. Examples of such a base material include polyester, triacetyl cellulose (TAC), cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyether sulphon, polysulphon, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, and the like. Examples thereof include plastic films such as polyether ketone, polymethyl methacrylate, polycarbonate, polyurethane and amorphous olefin (Cyclo-Olfin-Polymer: COP). The base material may be made by laminating two or more plastic films.
Among the above, a substrate selected from a triacetyl cellulose film, a polyester film, and an acrylic film is preferable. From the viewpoint of mechanical strength and dimensional stability, stretched polyester (polyethylene terephthalate, polyethylene naphthalate) is preferable, and TAC and acrylic are light-transmitting and optically isotropic. Suitable from the viewpoint.

The thickness of the base material is preferably 5 to 300 μm, more preferably 15 to 200 μm, and further preferably 25 to 100 μm from the viewpoint of strength and handleability.
In addition to physical treatment such as corona discharge treatment and oxidation treatment, a paint called an anchor agent or a primer may be applied to the surface of the base material in advance in order to improve the adhesiveness.

(Hard coat layer)
The hard coat layer has a role of increasing the surface hardness of the hard coat film and imparting scratch resistance to the hard coat film. In the present invention, the hard coat layer means a layer having a hardness of "H" or higher in a pencil hardness test. The hard coat layer in the present invention is preferably 2H to 6H, more preferably 3H to 6H in the pencil hardness test from the viewpoint of the balance between high hardness and scratch resistance.

The hard coat layer contains a binder resin having an oxyethylene structure and metal oxide particles. This makes it possible to increase the hardness of the surface of the hard-coated film and to impart excellent flexibility to the hard-coated film.

The content of the oxyethylene structure contained in the hardcourt layer is preferably 0.5 to 14% by mass, more preferably 2.5 to 13% by mass, still more preferably, with respect to the total mass of the hardcourt layer. It is 5.5 to 10% by mass. By setting the content to 0.5% by mass or more, it is possible to impart excellent flexibility to the hardcoat layer, improve the dispersibility of the metal oxide particles, and increase the hardness of the hardcoat layer. By setting the content to 14% by mass or less, it is possible to suppress a decrease in the hardness of the hard coat layer.

The content of the metal oxide particles contained in the hardcoat layer is preferably 20 to 60% by mass, more preferably 25 to 55% by mass, and further preferably 30 with respect to the total mass of the hardcoat layer. ~ 50% by mass. When it is 20% by mass or more, sufficient hardness can be imparted to the hard coat layer, and when it is 60% by mass or less, the decrease in flexibility can be suppressed.

Further, the hard coat layer contains (i) a polyfunctional (meth) acrylate compound having an oxyethylene group and a (meth) acryloyl group content of 6.0 mmol / g or more, and (ii) an oxyethylene group. It is preferably composed of a cured product of an ionizing radiation curable resin composition containing (A) an ionizing radiation curable resin and (B) metal oxide particles, which contains a polyfunctional (meth) acrylate compound which does not have.
Here, in the present invention, "(meth) acrylate" means acrylate or methacrylate.
Further, "ionizing radiation" means an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing or cross-linking a molecule, and usually ultraviolet (UV) or electron beam (EB) is used. In addition, electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as α-rays and ion rays can also be used.
Hereinafter, each component contained in the ionizing radiation curable resin composition will be described.

<Ionizing radiation curable resin composition>
[(A) Ionizing radiation curable resin]
The ionizing radiation curable resin of the component (A) is (i) a polyfunctional (meth) acrylate compound having an oxyethylene group and having a (meth) acryloyl group content of 6.0 mmol / g or more, and (ii). Includes polyfunctional (meth) acrylate compounds having no oxyethylene group. Here, the cured product of the ionizing radiation curable resin of the component (A) is a binder resin.

The polyfunctional (meth) acrylate compound of the component (i) is a polyfunctional (meth) acrylate compound having an oxyethylene group ( _-CH2 - _CH2 -O-), preferably 2 oxyethylene groups in the molecule. Have one or more.
The polyfunctional (meth) acrylate compound of the component (i) has a (meth) acryloyl group content of preferably 6.0 mmol / g or more, more preferably 6.0 to 8.5 mmol / g, and even more preferably. It is 6.5 to 8.0 mmol / g. When the hardness is 6.0 mmol / g or more, sufficient hardness can be obtained, and when the hardness is 8.5 mmol / g or less, the decrease in flexibility can be suppressed.
The (meth) acryloyl group content is a value calculated by 1000 / (meth) acrylic equivalent [g / eq].

The polyfunctional (meth) acrylate compound of the component (i) can impart flexibility by having an oxyethylene group. In addition, the dispersibility of the metal oxide particles of the component (B) described later can be improved, and the flexibility and hardness of the hard coat layer can be further enhanced.
Therefore, by blending the polyfunctional (meth) acrylate compound of the component (i) in the ionizing radiation curable resin composition, the hardness of the surface of the hard coat film is further increased, and the hard coat film has excellent flexibility. Can be given.

Examples of the polyfunctional (meth) acrylate compound of the component (i) include compounds represented by the following general formulas (1) to (6).

In the above general formulas (1) to (6), R ¹ to R ⁶ are independently hydrogen atoms or methyl groups, and hydrogen atoms are preferable from the viewpoint of curing rate. Further, from the viewpoint of the balance between hardness and flexibility, the compounds represented by the general formulas (1), (2) and (5) are preferable.
These may be used alone or in combination of two or more.

The content of the oxyethylene group contained in the polyfunctional (meth) acrylate compound of the component (i) is preferably 5 to 75% by mass, more preferably 10 to 70% by mass, and further preferably 20 to 60% by mass. be. When the content is 5% by mass or more, excellent flexibility can be imparted to the hard-coated film, the dispersibility of the metal oxide particles can be enhanced, and the hardness of the surface of the hard-coated film can be further enhanced. By setting the content to 75% by mass or less, it is possible to suppress a decrease in hardness of the hard coat layer.

The content of the oxyethylene group contained in the total solid content of the ionizing radiation curable resin composition is preferably 0.5 to 14% by mass, more preferably 2.5 to 13% by mass, and further preferably 5.5. ~ 10% by mass. When the content is 0.5% by mass or more, excellent flexibility can be imparted to the hardcoat film, the dispersibility of the metal oxide particles can be enhanced, and the hardness of the surface of the hardcoat film can be further enhanced. .. By setting the content to 14% by mass or less, it is possible to suppress a decrease in hardness of the hard coat layer.
Here, the "total solid content" means the one excluding the solvent.

Further, the content of the polyfunctional (meth) acrylate compound of the component (i) contained in the total amount of the component (A) is preferably 2 to 85% by mass, more preferably 4 from the viewpoint of the balance between hardness and flexibility. It is -80% by mass, more preferably 10 to 70% by mass.

The polyfunctional (meth) acrylate compound of the component (ii) is a compound having no oxyethylene group, and may be a polyfunctional (meth) acrylate compound other than the polyfunctional (meth) acrylate compound of the component (i) described above. However, the present invention is not particularly limited, and any of a monomer, an oligomer, and a polymer can be used.
By using (ii-a) a polyfunctional (meth) acrylate monomer or (ii-b) a polyfunctional (meth) acrylate oligomer as the component (ii), the hardness of the surface of the hard coat film can be increased. Further, by using the (ii-c) polyfunctional (meth) acrylate polymer, it is possible to impart flexibility to the hardcourt film and suppress curl generation due to reduction of curing shrinkage.
Therefore, from the viewpoint of high hardness, low curl, and flexibility, the polyfunctional (meth) acrylate compound is preferably a combination of a monomer or an oligomer and a polymer, and is a combination of the monomer and the polymer. Is more preferable.

Among the polyfunctional (meth) acrylate compounds, preferred bifunctional (meth) acrylate monomers include bisphenol A tetrapropoxydi (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nonanediol di. Examples thereof include (meth) acrylate.
Examples of the trifunctional or higher functional (meth) acrylate monomer include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and dipenta. Examples thereof include erythritol penta (meth) acrylate and isocyanuric acid-modified tri (meth) acrylate.
Further, as long as the performance of the present invention is not impaired, a part of the molecular skeleton of the (meth) acrylate monomer is modified with propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol and the like. Can be used.

The content of the acryloyl group contained in the polyfunctional (meth) acrylate monomer of the component (ii-a) is preferably 3.0 to 13.0 mmol / g, more preferably 6. It is 0 to 12.5 mmol / g, more preferably 8.0 to 12.0 mmol / g.

Further, the content of the polyfunctional (meth) acrylate monomer of the component (ii-a) contained in the total amount of the component (A) is preferably 0 to 78% by mass, more preferably 0 to 78% by mass, from the viewpoint of the balance between hardness and flexibility. It is 0 to 76% by mass, more preferably 10 to 60% by mass.

The polyfunctional (meth) acrylate oligomer of the component (ii-b) is not particularly limited as long as it is a bifunctional or higher functional (meth) acrylate-based oligomer. For example, a urethane (meth) acrylate oligomer or an epoxy (meth) acrylate oligomer. , Various (meth) acrylate-based oligomers such as polyester (meth) acrylate oligomers and polyether (meth) acrylate oligomers.
Urethane (meth) acrylate oligomers are obtained, for example, by reacting polyhydric alcohols and organic diisocyanates with hydroxy (meth) acrylates.
Further, the preferred epoxy (meth) acrylate oligomer is a (meth) acrylate obtained by reacting a trifunctional or higher functional aromatic epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, or the like with a (meth) acrylic acid. A (meth) acrylate obtained by reacting a polybasic acid with a polybasic acid and a (meth) acrylic acid with a functional or higher aromatic epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, etc., and a bifunctional or higher functional aromatic epoxy resin. , An alicyclic epoxy resin, an aliphatic epoxy resin, etc., and a (meth) acrylate obtained by reacting phenols with (meth) acrylic acid.

The polyfunctional (meth) acrylate oligomer of the component (ii-b) preferably has a weight average molecular weight (polystyrene-equivalent weight average molecular weight measured by the GPC method) of less than 4,000, more preferably more than 1,000. Less than 3,000.
Further, the polyfunctional (meth) acrylate oligomer of the component (ii-b) is more preferably 3 to 12 functional, still more preferably 3 to 10 functional, from the viewpoint of increasing the hardness.

The content of the acryloyl group contained in the polyfunctional (meth) acrylate oligomer of the component (ii-b) is preferably 2.0 mmol / g or more, more preferably 2.5 mmol / g or more, and further, from the viewpoint of hardness. It is preferably 3.0 mmol / g or more.

Further, the content of the polyfunctional (meth) acrylate oligomer of the component (ii-b) contained in the total amount of the component (A) is preferably 0 to 25% by mass, more preferably from the viewpoint of hardness, flexibility and curl. Is 5 to 25% by mass, more preferably 5 to 20% by mass.

The polyfunctional (meth) acrylate polymer of the (ii-c) component is not particularly limited as long as it is a bifunctional or higher functional (meth) acrylate polymer, for example, a urethane (meth) acrylate polymer or an epoxy (meth) acrylate polymer. , Polyester (meth) acrylate polymers, polyether (meth) acrylate polymers and other various (meth) acrylate-based polymers can be used.

The polyfunctional (meth) acrylate polymer of the component (ii-c) has a weight average molecular weight (polystyrene-equivalent weight average molecular weight measured by the GPC method) of 4,000 or more from the viewpoint of flexibility and low curl. It is preferably 10,000 to 100,000, more preferably 10,000 to 50,000. When the weight average molecular weight is 100,000 or less, the curability and coatability are good.
Further, the number of functional groups of the polyfunctional (meth) acrylate polymer of the (ii-c) component is not particularly limited, but from the viewpoint of curability, the number of functional groups per molecule is large (that is, the functional group equivalent is low). Is preferable. The functional group equivalent of the polyfunctional (meth) acrylate polymer is preferably 400 g / equivalent or less, more preferably 350 g / equivalent or less, still more preferably 300 g / equivalent or less.

The content of the acryloyl group contained in the polyfunctional (meth) acrylate polymer of the component (ii-c) is preferably 2.0 to 6.0 mmol / g, more preferably 2.5 to 5 from the viewpoint of hardness. It is 9.0 mmol / g, more preferably 3.0 to 4.0 mmol / g.

Further, the content of the polyfunctional (meth) acrylate polymer of the component (ii-c) contained in the total amount of the component (A) is preferably 0 to 25% by mass, more preferably from the viewpoint of hardness, flexibility and curl. Is 5 to 25% by mass, more preferably 5 to 20% by mass.

The total amount of (meth) acryloyl groups in the total amount of the component (A) is preferably 3.0 to 6.5 mmol / g, more preferably 3.3 to 6.3 mmol / g, and further preferably 3.5 to 3.5. It is 6.3 mmol / g. When the hardness is 3.0 mmol / g or more, sufficient hardness can be obtained, and when the hardness is 6.5 mmol / g or less, flexibility and low curl can be maintained.

The ratio of the polyfunctional (meth) acrylate compound of the component (i) to the polyfunctional (meth) acrylate compound of the component (ii) [(i) component / (ii) component] is from the viewpoint of the balance between hardness and flexibility. Therefore, it is preferably 0.04 to 4.5, and more preferably 0.2 to 4.0.
Further, the ratio of the (ii-a) component and the (ii-b) component to the (ii-c) component [(iii-a) + (ii-b) / (ii-c)] is the hardness and From the viewpoint of the balance of flexibility, it is preferably 0.0 to 5.5, more preferably 0.0 to 5.0.

The ratio of the oxyethylene group to the (meth) acryloyl group [oxyethylene group / (meth) acryloyl group] contained in the total amount of the component (A) is preferably 0.01 to 0.01 from the viewpoint of the balance between hardness and flexibility. It is 0.60, more preferably 0.05 to 0.55.

[(B) Metal oxide particles]
The metal oxide particles are components that impart hardness to the hard coat layer.
The average particle size of the metal oxide particles is preferably 5 to 100 nm, more preferably 8 to 80 nm, and even more preferably 10 to 60 nm. The metal oxide particles may be aggregated particles, and in the case of aggregated particles, the secondary particle diameter is preferably within the above range. When the average particle size of the metal oxide particles is 5 nm or more, sufficient hardness can be imparted to the hard coat layer, and when it is 100 nm or less, the transparency of the hard coat layer can be maintained.
In the present invention, the average particle size means a 50% average particle size, and for example, in the case of a composition, it can be obtained by using a Microtrac particle size analyzer (dynamic light scattering method) manufactured by Nikkiso Co., Ltd. can. Further, in the case of a cured product, the average particle diameter of the particles can be calculated by the following operations (1) to (3).
(1) The cross section of the hard coat film of the present invention is imaged by TEM or STEM. The acceleration voltage of TEM or STEM is preferably 10 kv to 30 kV, and the magnification is preferably 50,000 to 300,000 times.
(2) Arbitrary 10 particles are extracted from the observation image, the major axis and the minor axis of each particle are measured, and the particle size of each particle is calculated from the average of the major axis and the minor axis. The major axis is the longest diameter on the screen of each particle. Further, the minor axis is a line segment orthogonal to the midpoint of the line segment constituting the major axis, and refers to the distance between two points where the orthogonal line segment intersects the particle.
(3) The same operation is performed 5 times on the observation image on another screen of the same sample, and the value obtained from the number average of the particle diameters for a total of 50 particles is taken as the average particle diameter of the particles.

The metal oxide particles are preferably contained in an amount of 20 to 60% by mass, more preferably 25 to 55% by mass, based on the total solid content of the ionizing radiation curable resin composition. When it is 20% by mass or more, sufficient hardness can be imparted to the hard coat layer, and when it is 60% by mass or less, the decrease in flexibility can be suppressed.

The metal oxide particles are not limited to those having a single material or a single average particle diameter, but two or more kinds of metal oxide particles having different materials and average particle diameters may be used in combination. When two or more kinds are used in combination, it is preferable that the average particle diameter of each particle is within 5 to 100 nm and the total mass% of each particle is 20 to 60% by mass.

Examples of the metal oxide particles include silica particles, alumina particles, zirconia particles, titania particles, zinc oxide particles, and the like, and from the viewpoint of increasing hardness, silica particles and alumina particles are preferable, and silica particles are particularly preferable.

The metal oxide particles are preferably reactive metal oxide particles having a reactive group from the viewpoint of increasing the hardness. Reactive metal oxide particles are treated with a silane coupling agent on the surface of the metal oxide particles to introduce (meth) acryloyl group, epoxy group, oxetanyl group, etc., thereby ionizing and radiation curing the component (A). Reactivity with the sex resin is imparted, and the hardness of the hard coat layer can be further increased.

Preferred examples of the silane coupling agent include known silane coupling agents having a vinyl group, an epoxy group, a (meth) acryloyl group, an allyl group and the like, and more specifically, γ-methacryloxypropyltrimethoxysilane. γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyldimethylmethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyldimethylethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyl Methyldimethoxysilane, γ-acryloxypropyldimethylmethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropylmethyldiethoxysilane, γ-acryloxypropyldimethylethoxysilane, vinyltriethoxysilane, γ-glycid Xipropyltrimethoxysilane and the like are preferably mentioned, and more preferably, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and γ-methacryloxypropyldimethylmethoxysilane.

The method of surface-decorating the metal oxide particles with the silane coupling agent is not particularly limited and may be any known method. A dry method of spraying the silane coupling agent or a method of dispersing the metal oxide particles in a solvent is used. A wet method of adding a silane coupling agent and reacting with the silane coupling agent can be mentioned.

[Photopolymerization initiator]
When the ionizing radiation curable resin composition is an ultraviolet curable resin composition, a photopolymerization initiator can be blended.
Examples of the photopolymerization initiator include acetophenone-based, ketone-based, benzophenone-based, benzoin-based, ketal-based, anthraquinone-based, disulfide-based, thioxanthone-based, thiuram-based, and fluoroamine-based photopolymerization initiators. Of these, acetophenone-based, ketone-based, and benzophenone-based are preferable. Each of these photopolymerization initiators can be used alone, or a plurality of these photopolymerization initiators can be used in combination.

The content of the photopolymerization initiator in the ionizing radiation curable resin composition is preferably 0.5 to 10 parts by mass, more preferably 1 part by mass with respect to 100 parts by mass of the ionizing radiation curable resin from the viewpoint of curability. ~ 5 parts by mass.

The ionizing radiation curable resin composition may contain a resin component other than the above-mentioned (i) component and (ii) component as long as the performance of the present invention is not impaired. Examples of the resin component include thermoplastic resins and thermosetting resins. When the ionizing radiation curable resin composition contains a thermosetting resin, a curing agent is added as necessary.

[Other ingredients]
The ionizing radiation curable resin composition further contains additives such as a photopolymerization accelerator, a refractive index adjusting agent, an antiglare agent, an antifouling agent, an antistatic agent, a leveling agent, and an easy lubricant, if necessary. You can also do it.
The photopolymerization accelerator can reduce the polymerization inhibition due to air at the time of curing and accelerate the curing property, and is selected from, for example, p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester and the like. One or more types can be mentioned.

Further, the ionizing radiation curable resin composition can contain a solvent. The solvent can be used without particular limitation as long as it is a solvent that dissolves each component contained in the resin composition, but ketones, ethers or esters are preferable, and methyl ethyl ketone, methyl isobutyl ketone and propylene glycol monomethyl ether are preferable. At least one selected from is more preferred. The solvent can be used alone or in combination of two or more.
The content of the solvent in the ionizing radiation curable resin composition is usually 20 to 90% by mass, preferably 30 to 85% by mass, and more preferably 40 to 80% by mass. When the content of the solvent is within the above range, the coating suitability is excellent.

The method for forming the hard coat layer is not particularly limited as long as it can be formed with a uniform film thickness. For example, an ionizing radiation curable resin composition prepared by mixing other components such as the above-mentioned (A) ionizing radiation curable resin, (B) metal oxide particles, and a photopolymerization initiator is conventionally used on a substrate. It can be formed by applying it by a known coating method, drying it if necessary, and then irradiating it with ultraviolet rays (UV) to cure it.

The thickness (at the time of curing) of the hard coat layer can be appropriately selected depending on the strength of the base material and the required performance, and is usually 0.1 to 100 μm, preferably 5 to 20 μm. Further, it is more preferably 10 to 20 μm from the viewpoint of developing sufficient hardness and suppressing the occurrence of warpage and cracks.
The thickness of the hard coat layer can be calculated from the average value of the values at 20 points by measuring the thickness at 20 points from the image of the cross section taken by, for example, a scanning transmission electron microscope (STEM). The acceleration voltage of the STEM is preferably 10 kV to 30 kV. The STEM magnification is preferably 1000 to 7000 times.

It is preferable that the hard coat film of the present invention does not substantially contain particles having an average particle diameter of 1 mm or more in the hard coat layer. This is because it tends to be the starting point of cracks at the time of bending. The fact that the hard coat layer does not substantially contain particles having an average particle size of 1 mm or more means that the proportion of particles having an average particle size of 1 mm or more in the total solid content of the hard coat layer is 1% by mass or less. It means, preferably 0.1% by mass or less, more preferably 0.01% by mass or less, and further preferably 0% by mass.

The hard-coated film of the present invention preferably has a total light transmittance (JIS K7631-1: 1997) of 90% or more, and more preferably 92% or more. Further, the hard coat film of the present invention preferably has a haze (JIS K7136: 2000) of 1.0% or less, more preferably 0.7% or less, and more preferably 0.4% or less. More preferred.
The light incident surface when measuring the total light transmittance and the haze is on the substrate side.

The arithmetic mean roughness Ra (JIS B0601: 1994) of the surface of the hard coat film of the present invention (the surface on the hard coat layer side) is preferably 10 nm or less, and more preferably 3 nm or less.

Since the hard coat film of the present invention has high hardness and excellent flexibility, it is excellent in processability such as punching, router processing, cutting processing, cutting processing, and bending processing. Further, it can be used on the surface of an image display device such as a liquid crystal display, a CRT display, a projection display, a plasma display, an electroluminescence display, and a touch panel display.

<Display>
The display of the present invention includes the above-mentioned hard-coated film. Since the hard-coated film has high hardness and excellent flexibility, it can be suitably used for the surface of a display having a curved structure or a bendable display.
The display of the present invention can be used as a surface of a display device such as an electronic paper, a personal digital assistant (PDA), or a mobile phone.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited to the embodiments described in the examples.
The evaluation of the hard-coated films of Examples and Comparative Examples was performed as follows. The results are shown in Table 2.

ここで、式（Ｉ）中、Ｆ_ｍａｘは最大試験荷重（Ｎ）、Ａ_ｐは接触投影面積（ｍｍ^２）である。また、ｈ_ｒはナノインデンテーションから得られる荷重―変位曲線において、除荷曲線の接線より得られる深さ（ｍｍ）、ε＝０．７５である。 (1) Indentation hardness (HIT)
By the method described with reference to FIGS. 4 (a) and 4 (b), the maximum indentation depth h _max of the Vickers indenter (diamond) is set to 500 nm by using Picodenter HM-500 manufactured by Fisher Instruments Co., Ltd. The load F _max required for this was measured, and the indentation hardness (HIT) of the hard coat film was calculated from the following formula (I).

Here, in the formula (I), F _max is the maximum test load (N), and _Ap is the contact projection area (mm ² ). Further, hr is the depth (mm) obtained from the tangent of the unloading curve in the load-displacement curve obtained from the _{nanoindentation} , ε = 0.75.

(2) Bending resistance A mandrel test was performed in accordance with the cylindrical mandrel method specified in JIS-K5600-5-1 (1999). The value (mmφ) shown in Table 2 indicates the minimum mandrel diameter at which peeling or cracking of the hardcoat layer does not occur when the hardcourt film is wound around a mandrel rod with the hardcoat layer surface facing outward. The smaller the value, the better the flexibility.

(3) Pencil hardness test The hardness of the pencil scratch test is determined by adjusting the humidity of the prepared hard coat film for 2 hours under the conditions of a temperature of 25 ° C and a relative humidity of 60%, and then using a test pencil specified by JIS-S-6006. Then, a pencil hardness test (4.9 N load) specified in JIS K5600-5-4 (1999) was performed, and the highest pencil hardness that did not cause scratches was evaluated.

(4) A sample piece obtained by cutting a curl hard-coated film into 100 mm × 100 mm was placed on a horizontal table (flat surface), and the distance between two facing sides was measured. The curl evaluation was 30 mm or more.

Production Example 1 (Preparation of ionizing radiation curable resin composition)
The following components were mixed to prepare an ionizing radiation curable resin composition. The total amount of (meth) acryloyl groups in the total amount of (A) components was 4.5 mmol / g, and the content of oxyethylene groups contained in the total solid content was 0.6% by mass.
[(A) component]
-Ethylene oxide-modified (6EO-modified) dipentaerythritol hexaacrylate (having 6 oxyethylene groups in one molecule) (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., trade name NK ester A-DPH-6E, acryloyl group content : 7.1 mmol / g) 2 parts by mass, dipentaerythritol hexaacrylate (DPHA) (manufactured by Dicel Ornics Co., Ltd., trade name DPHA, acryloyl group content: 10.4 mmol / g) 38 parts by mass, reactive polymer (Manufactured by Kyoeisha Chemical Co., Ltd., trade name SMP-250AP, acryloyl group content: 4.0 mmol / g) 10 parts by mass [component (B)]
50 parts by mass of silica particles (manufactured by JGC Catalysts and Chemicals Co., Ltd., trade name V-8803, average particle diameter 25 nm) [Other components]
・ Photopolymerization initiator (BASF, trade name IRGACURE184) 4 parts by mass ・ Leveling agent (DIC, Megafuck F477) 0.1 parts by mass ・ Solvent Methyl isobutyl ketone (MIBK) 90 parts by mass, Methyl ethyl ketone (MEK) 10 parts by mass Department

Production Examples 2 to 6 (Preparation of Ionizing Radiation Curable Resin Composition)
Similar to Production Example 1, each component was mixed at the ratio shown in Table 1 to prepare an ionizing radiation curable resin composition. In Table 1, blanks indicate no compounding.

Production Example 7 (Preparation of ionizing radiation curable resin composition)
The following components were mixed to prepare an ionizing radiation curable resin composition. The total amount of (meth) acryloyl groups in the total amount of (A) components was 4.3 mmol / g, and the content of oxyethylene groups contained in the total solid content was 2.3% by mass.
[(A) component]
Ethylene oxide-modified (4EO-modified) dipentaerythritol hexaacrylate (having four oxyethylene groups in one molecule) (synthesized by the method described in Synthesis Example 2 of JP-A-2015-67680, acryloyl group content: 8 .0 mmol / g) 10 parts by mass · Dipentaerythritol hexaacrylate (DPHA) (manufactured by Daicel Ornics Co., Ltd., trade name DPHA, acryloyl group content: 10.4 mmol / g) 30 parts by mass · Reactive polymer (Kyoeisha) Made by Chemical Co., Ltd., trade name SMP-250AP, acryloyl group content: 4.0 mmol / g) 10 parts by mass [component (B)]
50 parts by mass of silica particles (manufactured by JGC Catalysts and Chemicals Co., Ltd., trade name V-8803, average particle diameter 25 nm) [Other components]
・ Photopolymerization initiator (BASF, trade name IRGACURE184) 4 parts by mass ・ Leveling agent (DIC, Megafuck F477) 0.1 parts by mass ・ Solvent MIBK 90 parts by mass, MEK 10 parts by mass

Production Example 8 (Preparation of ionizing radiation curable resin composition)
Similar to Production Example 7, each component was mixed at the ratio shown in Table 1 to prepare an ionizing radiation curable resin composition.

Production Example 9 (Preparation of Ionizing Radiation Curable Resin Composition)
The following components were mixed to prepare an ionizing radiation curable resin composition. The total amount of (meth) acryloyl groups in the total amount of (A) components was 4.2 mmol / g, and the content of oxyethylene groups contained in the total solid content was 5.8% by mass.
[(A) component]
-Ethethylene oxide-modified (4EO-modified) diacrylate (having four oxyethylene groups in one molecule) (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate 4EG-A, acryloyl group content: 6.6 mmol / g) 10 parts by mass, dipentaerythritol hexaacrylate (DPHA) (manufactured by Daicel Ornics Co., Ltd., trade name DPHA, acryloyl group content: 10.4 mmol / g) 30 parts by mass, reactive polymer (manufactured by Kyoeisha Chemical Co., Ltd.) , Trade name SMP-250AP, Acryloyl group content: 4.0 mmol / g) 10 parts by mass [Component (B)]
50 parts by mass of silica particles (manufactured by JGC Catalysts and Chemicals Co., Ltd., trade name V-8803, average particle diameter 25 nm) [Other components]
・ Photopolymerization initiator (BASF, trade name IRGACURE184) 4 parts by mass ・ Leveling agent (DIC, Megafuck F477) 0.1 parts by mass ・ Solvent MIBK 90 parts by mass, MEK 10 parts by mass

Production Example 10 (Preparation of Ionizing Radiation Curable Resin Composition)
The following components were mixed to prepare an ionizing radiation curable resin composition. The total amount of (meth) acryloyl groups in the total amount of (A) components was 4.3 mmol / g, and the content of oxyethylene groups contained in the total solid content was 5.1% by mass.
[(A) component]
-Ethethylene oxide-modified (3EO-modified) diacrylate (having three oxyethylene groups in one molecule) (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate 3EG-A, acryloyl group content: 7.7 mmol / g) 10 parts by mass, dipentaerythritol hexaacrylate (DPHA) (manufactured by Daicel Ornics Co., Ltd., trade name DPHA, acryloyl group content: 10.4 mmol / g) 30 parts by mass, reactive polymer (manufactured by Kyoeisha Chemical Co., Ltd.) , Trade name SMP-250AP, Acryloyl group content: 4.0 mmol / g) 10 parts by mass [Component (B)]
50 parts by mass of silica particles (manufactured by JGC Catalysts and Chemicals Co., Ltd., trade name V-8803, average particle diameter 25 nm) [Other components]
・ Photopolymerization initiator (BASF, trade name IRGACURE184) 4 parts by mass ・ Leveling agent (DIC, Megafuck F477) 0.1 parts by mass ・ Solvent MIBK 90 parts by mass, MEK 10 parts by mass

Production Example 11 (Preparation of ionizing radiation curable resin composition)
Similar to Production Example 10, each component was mixed at the ratio shown in Table 1 to prepare an ionizing radiation curable resin composition.

Production Example 12 (Preparation of Ionizing Radiation Curable Resin Composition)
The following components were mixed to prepare an ionizing radiation curable resin composition.
[(A) component]
・ Dipentaerythritol hexaacrylate (DPHA) (manufactured by Daicel Ornics Co., Ltd., trade name DPHA, acryloyl group content: 10.4 mmol / g) 40 parts by mass ・ Reactive polymer (manufactured by Kyoeisha Chemical Co., Ltd., trade name) SMP-250AP, acryloyl group content: 4.0 mmol / g) 10 parts by mass [component (B)]
-Silica particles (manufactured by Shin Nakamura Chemical Industry Co., Ltd., trade name V-8803, average particle diameter 25 nm) 50 parts by mass [Other components]
・ Photopolymerization initiator (BASF, trade name IRGACURE184) 4 parts by mass ・ Leveling agent (DIC, Megafuck F477) 0.1 parts by mass ・ Solvent MIBK 90 parts by mass, MEK 10 parts by mass

Production Example 13 (Preparation of Ionizing Radiation Curable Resin Composition)
The following components were mixed to prepare an ionizing radiation curable resin composition. The total amount of (meth) acryloyl groups in the total amount of (A) components was 3.6 mmol / g, and the content of oxyethylene groups contained in the total solid content was 15.7% by mass.
[(A) component]
-Ethylene oxide-modified (6EO-modified) dipentaerythritol hexaacrylate (having 6 oxyethylene groups in one molecule) (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., trade name NK ester A-DPH-6E, acryloyl group content : 7.1 mmol / g) 50 parts by mass [Component (B)]
50 parts by mass of silica particles (manufactured by JGC Catalysts and Chemicals Co., Ltd., trade name V-8803, average particle diameter 25 nm) [Other components]
・ Photopolymerization initiator (BASF, trade name IRGACURE184) 4 parts by mass ・ Leveling agent (DIC, Megafuck F477) 0.1 parts by mass ・ Solvent MIBK 90 parts by mass, MEK 10 parts by mass

Production Example 14 (Preparation of ionizing radiation curable resin composition)
The following components were mixed to prepare an ionizing radiation curable resin composition. The total amount of (meth) acryloyl groups in the total amount of (A) components was 3.4 mmol / g, and the content of oxyethylene groups contained in the total solid content was 14.1% by mass.
[(A) component]
-Ethethylene oxide modified (6EO modified) dipentaerythritol hexaacrylate (having 6 oxyethylene groups in one molecule) (manufactured by Shin Nakamura Chemical Industry Co., Ltd., trade name NK ester A-DPH-6E, acryloyl group content : 7.1 mmol / g) 45 parts by mass ・ Reactive polymer (manufactured by Kyoeisha Chemical Industry Co., Ltd., trade name SMP-250AP, acryloyl group content: 4.0 mmol / g) 5 parts by mass [(B) component]
50 parts by mass of silica particles (manufactured by JGC Catalysts and Chemicals Co., Ltd., trade name V-8803, average particle diameter 25 nm) [Other components]
・ Photopolymerization initiator (BASF, trade name IRGACURE184) 4 parts by mass ・ Leveling agent (DIC, Megafuck F477) 0.1 parts by mass ・ Solvent MIBK 90 parts by mass, MEK 10 parts by mass

Production Example 15 (Preparation of ionizing radiation curable resin composition)
The following components were mixed to prepare an ionizing radiation curable resin composition. The total amount of (meth) acryloyl groups in the total amount of (A) components was 3.3 mmol / g, and the content of oxyethylene groups contained in the total solid content was 11.9% by mass.
[(A) component]
Ethylene oxide-modified (12EO-modified) dipentaerythritol hexaacrylate (having 12 oxyethylene groups in one molecule) (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., trade name NK ester A-DPH-12E, acryloyl group content : 5.4 mmol / g) 25 parts by mass, dipentaerythritol hexaacrylate (DPHA) (manufactured by Dicel Ornics Co., Ltd., trade name DPHA, acryloyl group content: 10.4 mmol / g) 15 parts by mass, reactive polymer (Manufactured by Kyoeisha Chemical Co., Ltd., trade name SMP-250AP, acryloyl group content: 4.0 mmol / g) 10 parts by mass [component (B)]
50 parts by mass of silica particles (manufactured by JGC Catalysts and Chemicals Co., Ltd., trade name V-8803, average particle diameter 25 nm) [Other components]
・ Photopolymerization initiator (BASF, trade name IRGACURE184) 4 parts by mass ・ Leveling agent (DIC, Megafuck F477) 0.1 parts by mass ・ Solvent MIBK 90 parts by mass, MEK 10 parts by mass

Production Example 16 (Preparation of Ionizing Radiation Curable Resin Composition)
The following components were mixed to prepare an ionizing radiation curable resin composition. The total amount of (meth) acryloyl groups in the total amount of (A) components was 6.6 mmol / g, and the content of oxyethylene groups contained in the total solid content was 8.9% by mass.
[(A) component]
-Ethylene oxide-modified (3EO-modified) diacrylate (having three oxyethylene groups in one molecule) (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate 3EG-A, acryloyl group content: 7.7 mmol / g) 20 parts by mass, dipentaerythritol hexaacrylate (DPHA) (manufactured by Daicel Ornics Co., Ltd., trade name DPHA, acryloyl group content: 10.4 mmol / g) 50 parts by mass [component (B)]
30 parts by mass of silica particles (manufactured by JGC Catalysts and Chemicals Co., Ltd., trade name V-8803, average particle diameter 25 nm) [Other components]
・ Photopolymerization initiator (BASF, trade name IRGACURE184) 4 parts by mass ・ Leveling agent (DIC, Megafuck F477) 0.1 parts by mass ・ Solvent MIBK 90 parts by mass, MEK 10 parts by mass

Production Example 17 (Preparation of ionizing radiation curable resin composition)
The following components were mixed to prepare an ionizing radiation curable resin composition. The total amount of (meth) acryloyl groups in the total amount of (A) components was 2.9 mmol / g, and the content of oxyethylene groups contained in the total solid content was 3.1% by mass.
[(A) component]
-Ethylene oxide-modified (6EO-modified) dipentaerythritol hexaacrylate (having 6 oxyethylene groups in one molecule) (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., trade name NK ester A-DPH-6E, acryloyl group content : 7.1 mmol / g) 10 parts by mass, dipentaerythritol hexaacrylate (DPHA) (manufactured by Dicel Ornics Co., Ltd., trade name DPHA, acryloyl group content: 10.4 mmol / g) 10 parts by mass, reactive polymer (Manufactured by Kyoeisha Chemical Co., Ltd., trade name SMP-250AP, acryloyl group content: 4.0 mmol / g) 30 parts by mass [component (B)]
-Silica particles (manufactured by Shin Nakamura Chemical Industry Co., Ltd., trade name V-8803, average particle diameter 25 nm) 50 parts by mass [Other components]
・ Photopolymerization initiator (BASF, trade name IRGACURE184) 4 parts by mass ・ Leveling agent (DIC, Megafuck F477) 0.1 parts by mass ・ Solvent MIBK 90 parts by mass, MEK 10 parts by mass

Production Example 18 (Preparation of Ionizing Radiation Curable Resin Composition)
The following components were mixed to prepare an ionizing radiation curable resin composition.
・ Pentaerythritol triacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name PE-3A) 15 parts by mass ・ Pentaerythritol tetraacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name PE-4A) 15 parts by mass ・ Urethane acrylate (Kyoeisha Chemical Co., Ltd.) 25 parts by mass of photopolymerization initiator (BASF, trade name IRGACURE184) 3 parts by mass of leveling agent (Big Chemy Japan, BYK-350) 0.1 parts by mass of methyl ethyl ketone (MEK) 43 parts by mass

Example 1 (Manufacturing of Hardcourt Film)
The ionizing radiation curable resin composition obtained in Production Example 1 was applied onto a triacetyl cellulose (TAC) substrate (manufactured by Konica Minolta, KC8UA, thickness 80 μm) to form a coating film. The coating film was dried at 70 ° C. for 60 seconds to remove the solvent. Next, the coating film is irradiated with ultraviolet rays at an irradiation amount of 136 mJ / cm ² using an ultraviolet irradiation device to cure the coating film, and a hard coat film having a hard coat (HC) layer having a film thickness of 14 μm after curing is obtained. Obtained.
FIG. 2 shows an SEM photograph of the cross section of the obtained hard coat film taken with a scanning electron microscope. In the SEM photograph, the silica particles present at a depth of 1.5 μm (l ₁ ) from the surface of the hard coat layer and the silica particles present at a height of 1 μm (l ₂ ) from the interface between the substrate and the hard coat layer. There was no bias between them.

Examples 2 to 11 (Manufacturing of hard-coated film)
Hard coat in the same manner as in Example 1 except that the ionizing radiation curable resin composition obtained in Production Examples 2 to 11 was used instead of the ionizing radiation curable resin composition obtained in Production Example 1. I got a film.

Comparative Examples 1 to 6 (Manufacturing of hard-coated film)
Hard coat in the same manner as in Example 1 except that the ionizing radiation curable resin composition obtained in Production Examples 12 to 18 was used instead of the ionizing radiation curable resin composition obtained in Production Example 1. I got a film.

FIG. 3 shows an SEM photograph of the cross section of the hard coat film obtained in Comparative Example 1 taken with a scanning electron microscope. In the SEM photograph, the silica particles existing at a depth of 1.5 μm (l ₁ ) from the surface of the hard coat layer are sparse, whereas the silica particles are sparse at a height of 1 μm (l ₂ ) from the interface between the substrate and the hard coat layer. The silica particles present were dense, and the silica particles contained in the hardcoat layer were unevenly distributed.

Comparative Example 7 (Manufacturing of Hardcourt Film)
The ionizing radiation curable resin composition obtained in Production Example 18 is dried by a bar coating method on a triacetyl cellulose (TAC) substrate (Konica Minolta, KC8UA, thickness 80 μm) to a thickness of 5 μm. It was coated and dried. Then, a hard coat layer was formed by irradiating ultraviolet rays of 300 mJ / cm ² with a high-pressure mercury lamp in an atmosphere having an oxygen concentration of 1000 ppm to prepare a hard coat film.

(Summary of results)
From Examples 1 to 11, it can be seen that the hard coat film having the hard coat layer formed by using the ionizing radiation curable resin composition of the present invention has high hardness and excellent flexibility. On the other hand, in Comparative Examples 1 to 7 using the resin compositions that do not satisfy the requirements of the ionizing radiation curable resin composition of the present invention, it can be seen that the hardness or flexibility is low in each of them.

Since the hard coat film of the present invention has high hardness and excellent flexibility, it can be used on the surface of an image display device such as a liquid crystal display, a CRT display, a projection display, a plasma display, an electroluminescence display, and a touch panel display. In particular, it can be suitably used for the surface of a display having a curved structure or a bendable display.

1, 11: Base material 2, 12: Hard coat layer 10, 20: Hard coat film 12a: Surface 30: Vickers indenter

Claims (12)

A hardcoat film having a hardcoat layer on a substrate.
The hard coat layer is a cured product of an ionizing radiation curable resin composition containing (A) an ionizing radiation curable resin and (B) metal oxide particles.
The component (A) has (i) a polyfunctional (meth) acrylate compound having an oxyethylene group and a (meth) acryloyl group content of 6.0 mmol / g or more, and (ii) an oxyethylene group. Does not contain polyfunctional (meth) acrylate compounds and
The polyfunctional (meth) acrylate compound of the component (ii) is (ii-a) a polyfunctional (meth) acrylate monomer having a content of 10 to 78% by mass in the total amount of the component (A), or (ii). -B) The polyfunctional (meth) acrylate oligomer having a content of 5 to 25% by mass in the total amount of the (A) component and (ii-c) a content of 5 to 25% by mass in the total amount of the (A) component. % In combination with a polyfunctional (meth) acrylate polymer,
The total amount of (meth) acryloyl groups in the total amount of the (A) component is 3.0 to 6.5 mmol / g, and the content of oxyethylene groups contained in the total solid content is 0.5 to 14 mass by mass. % And
The indentation hardness (HIT) measured by pushing the Vickers indenter into the hard coat layer is 600 N / mm ² or more when the maximum pushing depth of the Vickers indenter is 500 nm, and JIS-K5600. -A hard coat film having a minimum diameter of 20 mm or less in a mandrel in a bending resistance test measured by a cylindrical mandrel method according to 5-1 (1999). The hardcoat film according to claim 1, wherein the metal oxide particles have a reactive group. The hardcoat film according to claim 1 or 2 , wherein the metal oxide particles are silica particles. The invention according to any one of claims 1 to 3, wherein the polyfunctional (meth) acrylate compound of (i) has a (meth) acryloyl group content of 6.0 mmol / g or more and 8.5 mmol / g or less. Hard coat film. The polyfunctional (meth) acrylate compound of the component (ii) is (ii-a) a polyfunctional (meth) acrylate monomer having a content of 10 to 78% by mass in the total amount of the component (A) and (ii-). c) It is a combination with a polyfunctional (meth) acrylate polymer having a content of 5 to 25% by mass in the total amount of the component (A).
The content of the (meth) acryloyl group contained in the polyfunctional (meth) acrylate monomer of the component (ii-a) is 3.0 to 13.0 mmol / g.
Any one of claims 1 to 4, wherein the content of the (meth) acryloyl group contained in the polyfunctional (meth) acrylate polymer of the component (ii-c) is 2.0 to 6.0 mmol / g. The hard coat film described in. The polyfunctional (meth) acrylate compound of the component (ii) is (ii-b) a polyfunctional (meth) acrylate oligomer having a content of 5 to 25% by mass in the total amount of the component (A) and (ii-). c) It is a combination with a polyfunctional (meth) acrylate polymer having a content of 5 to 25% by mass in the total amount of the component (A).
The content of the (meth) acryloyl group contained in the polyfunctional (meth) acrylate oligomer of the component (ii-b) is 2.0 mmol / g or more, and the content is 2.0 mmol / g or more.
Any one of claims 1 to 4, wherein the content of the (meth) acryloyl group contained in the polyfunctional (meth) acrylate polymer of the component (ii-c) is 2.0 to 6.0 mmol / g. The hard coat film described in. The hard coat film according to any one of claims 1 to 6 , wherein the hard coat layer has a thickness of 5 to 20 μm. A display having a curved structure or a bendable structure provided with the hard-coated film according to any one of claims 1 to 7 . It contains (A) an ionizing radiation curable resin and (B) metal oxide particles, and the component (A) has (i) an oxyethylene group and a (meth) acryloyl group content of 6.0 mmol /. It contains a polyfunctional (meth) acrylate compound having a concentration of g or more and (ii) a polyfunctional (meth) acrylate compound having no oxyethylene group.
The polyfunctional (meth) acrylate compound of the component (ii) is (ii-a) a polyfunctional (meth) acrylate monomer having a content of 10 to 78% by mass in the total amount of the component (A), or (ii). -B) The polyfunctional (meth) acrylate oligomer having a content of 5 to 25% by mass in the total amount of the (A) component and (ii-c) a content of 5 to 25% by mass in the total amount of the (A) component. % In combination with a polyfunctional (meth) acrylate polymer,
The total amount of (meth) acryloyl groups in the total amount of the (A) component is 3.0 to 6.5 mmol / g, and the content of oxyethylene groups contained in the total solid content is 0.5 to 14 mass by mass. %, Ionizing radiation curable resin composition. The ionizing radiation curable resin composition according to claim 9, wherein the polyfunctional (meth) acrylate compound of (i) has a (meth) acryloyl group content of 6.0 mmol / g or more and 8.5 mmol / g or less. .. The polyfunctional (meth) acrylate compound of the component (ii) is (ii-a) a polyfunctional (meth) acrylate monomer having a content of 10 to 78% by mass in the total amount of the component (A) and (ii-). c) It is a combination with a polyfunctional (meth) acrylate polymer having a content of 5 to 25% by mass in the total amount of the component (A).
The content of the (meth) acryloyl group contained in the polyfunctional (meth) acrylate monomer of the component (ii-a) is 3.0 to 13.0 mmol / g.
The ionizing radiation according to claim 9 or 10, wherein the content of the (meth) acryloyl group contained in the polyfunctional (meth) acrylate polymer of the component (ii-c) is 2.0 to 6.0 mmol / g. Curable resin composition. The polyfunctional (meth) acrylate compound of the component (ii) is (ii-b) a polyfunctional (meth) acrylate oligomer having a content of 5 to 25% by mass in the total amount of the component (A) and (ii-). c) It is a combination with a polyfunctional (meth) acrylate polymer having a content of 5 to 25% by mass in the total amount of the component (A).
The content of the (meth) acryloyl group contained in the polyfunctional (meth) acrylate oligomer of the component (ii-b) is 2.0 mmol / g or more, and the content is 2.0 mmol / g or more.
The ionizing radiation according to claim 9 or 10, wherein the content of the (meth) acryloyl group contained in the polyfunctional (meth) acrylate polymer of the component (ii-c) is 2.0 to 6.0 mmol / g. Curable resin composition.

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