JP5641036B2 - Antireflection article and image display device - Google Patents

Description

  The present invention relates to an antireflection article and an image display device.

  In recent years, regarding an antireflection film, which is a film-shaped antireflection article, there has been proposed a method for preventing reflection by arranging a large number of microprotrusions closely on the surface of a transparent substrate (transparent film) (patent) References 1-3). In this method, the refractive index with respect to incident light is continuously changed in the thickness direction, thereby eliminating the discontinuous interface of the refractive index and preventing reflection.

  The film having a large number of microprojections has high antireflection performance. However, due to its surface structure, dirt such as sebum is likely to adhere, and the dirt penetrates into the groove between the microprotrusions, so that it is difficult to remove and the surface appearance tends to deteriorate.

Patent Document 4 describes a fine concavo-convex structure made of a cured product of a specific active energy ray-curable resin composition as a fine concavo-convex structure excellent in contaminant removal and also having scratch resistance. . In Patent Document 4, the cured product of the specific resin composition described above has a specific composition, whereby the crosslink density is increased, the elastic modulus and hardness of the cured product are increased, and the scratch resistance is increased. Contaminant by making it easy to allow water to enter between the surface of the fine concavo-convex structure and the contaminant adhering to the surface. It is described that it has excellent removability.
According to the method of Patent Document 4, since the cross-linking density is increased to increase the hardness of the fine concavo-convex structure, the fine concavo-convex structure is difficult to deform, and it is difficult to reach the gaps of the fine concavo-convex structure during wiping. . Therefore, when wiping off the contaminants, it is necessary to lift off the dirt with a cleaner or the like containing water or alcohol, and it is difficult to remove the dirt by dry wiping.

Japanese Patent Laid-Open No. 50-70040 Special Table 2003-531962 Japanese Patent No. 4632589 International Publication No. 2012/096322 Pamphlet

  In the antireflection article including the fine uneven layer, when removing dirt that has penetrated to the back of the groove between the microprojections, conventionally, using a cloth containing water, alcohol, etc. The dirt surfaced and was wiped off. However, for example, an image display device provided in an electronic device such as a mobile phone is not preferable to wipe with water, and thus an antireflection article including a fine uneven layer that can be wiped off with dry wiping is required.

  The present invention has been made in view of the above circumstances, and the antireflection article including a fine uneven layer capable of wiping dirt with dry wiping without reducing the antireflection performance, and the antireflection performance is lowered. An object of the present invention is to provide an image display device capable of wiping off dirt by dry wiping.

The antireflective article according to the present invention includes an antireflective layer comprising at least one surface side of a transparent substrate, which is made of a cured resin composition and has a fine uneven layer having a fine uneven shape on the surface opposite to the transparent substrate. Goods,
The surface of the fine concavo-convex layer has a fine concavo-convex shape provided with a group of fine protrusions formed by a collection of fine protrusions, and the microprotrusions have the shortest wavelength of the wavelength band of light for preventing reflection as Λ _min . When the maximum value of the distance d between adjacent protrusions of the protrusion is _dmax ,
d _max ≦ Λ _min
And the cross-sectional area occupancy rate of the material portion forming the microprojection in the horizontal cross section when it is assumed that the microprojection is cut in a horizontal plane perpendicular to the depth direction of the microprojection is It has a structure that increases gradually and gradually as it approaches the deepest part from the top,
The storage elastic modulus (E ′) at 25 ° C. of the cured product of the resin composition is 1 MPa or more and 300 MPa or less, and the loss elastic modulus with respect to the storage elastic modulus (E ′) at 25 ° C. of the cured product of the resin composition. The ratio (tan δ (= E ″ / E ′)) of (E ″) is 0.2 or less.

  In the antireflection article according to the present invention, the contact angle of n-hexadecane on the surface of the cured product of the resin composition is 30 degrees or less, or the contact angle of oleic acid is 25 degrees or less. This is preferable from the viewpoint of improved visibility.

  In the antireflection article according to the present invention, the resin composition contains a compound having a long-chain alkyl group having 10 or more carbon atoms, so that attached dirt can be easily removed and the visibility after dry wiping is improved. It is preferable from the point of becoming good.

  The image display device according to the present invention includes the antireflection article according to the present invention on at least one side of a display panel.

  According to the present invention, an antireflection article including a fine uneven layer that can be wiped off by dry wiping without deteriorating the antireflection performance, and wiping off dirt by dry wiping without deteriorating the antireflection performance. It is possible to provide an image display device capable of performing the above.

FIG. 1 is a cross-sectional view schematically showing an example of an antireflection article according to the present invention. FIG. 2 is a cross-sectional view schematically showing an example of an image display device according to the present invention. FIG. 3 is a diagram illustrating an example of a Delaunay diagram. FIG. 4 is a frequency distribution diagram used for measuring the distance between adjacent protrusions. FIG. 5 is a frequency distribution diagram for explaining the minute height. FIG. 6 is a schematic view showing an example of a method for producing an antireflection article according to the present invention. FIG. 7 is a scatter diagram showing the relationship between the storage elastic modulus E ′ and the loss tangent tan δ of the example and the comparative example.

Hereinafter, the antireflection article and the image display device according to the present invention will be described in detail in order.
In the present invention, (meth) acryl means either acryl or methacryl, and (meth) acrylate means either acrylate or methacrylate.

[Anti-reflective article]
The antireflective article according to the present invention includes an antireflective layer comprising at least one surface side of a transparent substrate, which is made of a cured resin composition and has a fine uneven layer having a fine uneven shape on the surface opposite to the transparent substrate. Goods,
The surface of the fine concavo-convex layer has a fine concavo-convex shape provided with a group of fine protrusions formed by a collection of fine protrusions, and the microprotrusions have the shortest wavelength of the wavelength band of light for preventing reflection as Λ _min . When the maximum value of the distance d between adjacent protrusions of the protrusion is _dmax ,
d _max ≦ Λ _min
And the cross-sectional area occupancy rate of the material portion forming the microprojection in the horizontal cross section when it is assumed that the microprojection is cut in a horizontal plane perpendicular to the depth direction of the microprojection is It has a structure that increases gradually and gradually as it approaches the deepest part from the top,
The storage elastic modulus (E ′) at 25 ° C. of the cured product of the resin composition is 300 MPa or less, and the loss elastic modulus (E) relative to the storage elastic modulus (E ′) at 25 ° C. of the cured product of the resin composition. ”) (Tan δ (= E ″ / E ′), hereinafter may be referred to as loss tangent) is 0.2 or less.

The antireflection article according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing an example of an antireflection article according to the present invention. An antireflection article 10 shown in FIG. 1 has a fine uneven layer 2 having a fine uneven shape on one surface side of a transparent substrate 1.
The surface of the fine uneven layer 2 has a fine uneven shape with a fine projection group fine projections 3 will be set, the microprojections 3, the shortest wavelength in the wavelength band of light to improve the anti-reflection lambda _min When the maximum value of the adjacent protrusion interval d (FIG. 1) of the minute protrusion 3 is d _max ,
d _max ≦ Λ _min
And the cross-sectional area occupancy rate of the material portion forming the microprojections 3 in the horizontal cross section when it is assumed that the microprojections are cut in a horizontal plane perpendicular to the depth direction of the microprojections is 3 has a structure that increases gradually and gradually from the top to the deepest part. When the fine concavo-convex layer 2 has such a structure, it is possible to prevent reflection of light having a wavelength of Λ _min or more.

  In the antireflection article of the present invention, the fine concavo-convex layer is made of a cured product of the resin composition, the storage elastic modulus (E ′) at 25 ° C. of the cured product of the resin composition is 300 MPa or less, and the resin The ratio of the loss elastic modulus (E ″) to the storage elastic modulus (E ′) at 25 ° C. of the cured product of the composition (tan δ (= E ″ / E ′)) is 0.2 or less. It is possible to wipe off dirt by dry wiping.

The present inventors have paid attention to the fact that pressure is applied to the fine protrusions when wiping the contaminants attached to the surface of the fine uneven layer. The present inventors have designed that the microprotrusions are deformed by the pressure at the time of wiping and the grooves between the protuberances are widened, or the grooves between the protuberances are filled, so that the contaminants adhered between the microprotrusions. We thought that it would be easy to scrape out mechanically and that it would be possible to wipe off the dirt with dry wiping.
Conventional antireflective articles have been widely used in which the hardness of the microprojections is high from the viewpoint of scratch resistance. Since the fine protrusions with high hardness hardly deform even when pressure is applied during wiping, it is difficult to wipe off the dirt by dry wiping.
On the other hand, the microprotrusions that can be easily deformed by the pressure are likely to be crushed or sticking by the pressure, so that a wiping mark may remain at the wiped portion.
In this invention, the hardened | cured material of the resin composition which has the said specific physical property is used as a fine uneven | corrugated layer. The cured product of the resin composition has a storage elastic modulus (E ′) of 300 MPa or less and a loss tangent (tan δ) of 0.2 or less. It is deformed by pressure and has excellent elastic resilience. Therefore, when wiping dirt with dry wiping, the micro-protrusions are deformed by the pressure, making it easy to mechanically scrape the dirt adhering between the micro-protrusions, and then plastic deformation occurs when the pressure is removed It restores the original shape of the microprojections. For this reason, the antireflection article of the present invention can wipe off dirt without deteriorating the antireflection performance even when it is dry wiped.
The size of the pressure when Ri wipe in the invention is not particularly limited, usually, is about 2~5kg / cm ² pressure of about.
Hereinafter, the transparent base material and the fine uneven layer included in the antireflection article according to the present invention will be described in order.

<Transparent substrate>
The transparent base material used for this invention can be suitably selected and used according to a use from the well-known transparent base materials used for an antireflection article. Specific examples of materials used for the transparent substrate include, for example, acetyl cellulose resins such as triacetyl cellulose, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, olefin resins such as polyethylene and polymethylpentene, and acrylic resins. Transparent resins such as resin, polyurethane resin, polyethersulfone, polycarbonate, polysulfone, polyether, polyetherketone, acrylonitrile, methacrylonitrile, cycloolefin polymer, cycloolefin copolymer, soda glass, potassium glass, lead glass And glass, ceramics such as PLZT, transparent inorganic materials such as quartz and fluorite, and the like.

  The transparent substrate preferably has a transmittance in the visible light region of 80% or more, and more preferably 90% or more. Here, the transmittance | permeability of a transparent base material can be measured by JISK7361-1 (the test method of the total light transmittance of a plastic-transparent material).

  Although the thickness of the said transparent base material can be suitably set according to the use of the antireflective article of this invention, Although it does not specifically limit, Usually, it is 20-5000 micrometers, The said transparent base material is supplied with the form of a roll. However, it may be any one of those that do not bend to the extent that they can be wound, but that can be bent by applying a load, or those that do not bend completely.

The configuration of the transparent substrate used in the present invention is not limited to a configuration consisting of a single layer, and may have a configuration in which a plurality of layers are laminated. When it has the structure by which the several layer was laminated | stacked, the layer of the same composition may be laminated | stacked, and the several layer which has a different composition may be laminated | stacked.
Moreover, you may form the primer layer for improving the adhesiveness of a transparent base material and the fine uneven | corrugated layer mentioned later, and by extension, abrasion resistance (scratch resistance) on a transparent base material. This primer layer preferably has adhesion to both the transparent substrate and the fine concavo-convex structure and transmits visible light.

<Fine uneven layer>
The surface of the fine concavo-convex layer has a fine concavo-convex shape provided with a group of fine protrusions formed by a collection of fine protrusions. The shape of the microprotrusions is such that the cross-sectional area occupancy of the material part forming the microprotrusions in the horizontal cross section when it is assumed that the microprojections are cut in a horizontal plane perpendicular to the depth direction of the microprotrusions is What is necessary is just to select suitably from what has a structure which increases gradually gradually as it approaches the deepest part direction. Specific examples of the shape of such microprojections include those having a vertical cross-sectional shape such as a semicircular shape, a semi-elliptical shape, a triangular shape, a parabolic shape, and a bell shape. The plurality of microprojections may have the same shape or different shapes. Since the fine protrusion has the above-described shape, the refractive index continuously changes in the depth direction such as fine unevenness, and thus antireflection properties are imparted.

In the present invention, the distance d between adjacent protrusions and the height H of the minute protrusions are measured by the following method.
(1) First, an in-plane arrangement of projections (planar shape of the projection arrangement) is detected using an atomic force microscope (AFM) or a scanning electron microscope (SEM).

  (2) Subsequently, a maximum point of the height of each protrusion (hereinafter simply referred to as a maximum point) is detected from the obtained in-plane arrangement. There are various methods for obtaining the maximum point, such as a method of sequentially comparing the planar view shape and the enlarged photograph of the corresponding cross-sectional shape to obtain the maximum point, and a method of obtaining the maximum point by image processing of the plan view enlarged photo. Can be applied.

  (3) Next, a Delaunay diagram with the detected maximum point as a generating point is created. Here, Delaunay diagram is obtained by dividing the Voronoi region adjacent to the Voronoi region when the Voronoi division is performed with each local maximum as the generating point, and connecting the adjacent generating points with line segments. This is a net-like figure made up of triangular aggregates. Each triangle is called a Delaunay triangle, and a side of each triangle (a line segment connecting adjacent generating points) is called a Delaunay line. FIG. 3 is a diagram in which a Delaunay diagram (a diagram represented by a white line segment) is superimposed on the original image.

  (4) Next, the frequency distribution of the line segment length of each Delaunay line, that is, the frequency distribution of the distance between adjacent maximum points (hereinafter referred to as the distance between adjacent protrusions) is obtained. FIG. 4 is a histogram of the frequency distribution created from the Delaunay diagram of FIG. In addition, when there is a groove-like recess at the top of the protrusion, or when the top is split into a plurality of peaks, from the obtained frequency distribution, the microstructure in which there is a recess at the top of such protrusion, The data resulting from the fine structure in which the top part is divided into a plurality of peaks is removed, and only the data of the projection body itself is selected to create a frequency distribution.

  Specifically, a fine structure in which a concave portion exists on the top of the protrusion, or a fine structure related to a fine protrusion (multi-modal micro protrusion) in which the top is divided into a plurality of peaks has such a fine structure. The distance between adjacent protrusions is clearly different from the numerical range in the case of non-protruding microprotrusions (single-peak microprotrusions). Thus, by removing the corresponding data using this feature, only the data of the projection body itself is selected and the frequency distribution is detected. More specifically, for example, about 5 to 20 adjacent single-peaked microprojections are selected from an enlarged photograph of the microprojections (group) in plan view, and the value of the distance between the adjacent projections is sampled. The frequency distribution is excluded by excluding values that are clearly out of the numerical range obtained by sampling (usually, data having a value of 1/2 or less of the average distance between adjacent protrusions obtained by sampling). To detect. In the example of FIG. 4, data having a distance between adjacent protrusions of 56 nm or less (the leftmost small mountain indicated by the arrow A) is excluded. FIG. 4 shows a frequency distribution before such exclusion processing is performed.

(5) The average value d _AVG and the standard deviation σ are obtained from the frequency distribution of the distance d between adjacent protrusions thus obtained. Here, when the frequency distribution obtained in this manner is regarded as a normal distribution and the average value d _AVG and the standard deviation σ are obtained, the average value d _AVG = 158 nm and the standard deviation σ = 38 nm are obtained in the example of FIG. Thus, the maximum value of the distance d between adjacent protrusions is set to d _max = d _AVG + 2σ, and in this example, d _max = 234 nm.

The same method is applied to define the height of the protrusion. In this case, a relative height difference of each local maximum point position from a specific reference position is acquired from the local maximum point obtained by the above (2), and is histogrammed. FIG. 5 is a diagram showing a histogram of the frequency distribution of the protrusion height H with the protrusion root position obtained in this way as a reference (height 0). The average value _HAVG of the protrusion height and the standard deviation σ are obtained from the frequency distribution based on the histogram. Here in the example of FIG. 5, the mean value _H AVG = 178 nm, the standard deviation sigma = 30 nm. Thus in this example, the height of the projections is an average value _H AVG = 178 nm. In the histogram of the projection height H shown in FIG. 5, in the case of a multi-peak microprojection, the plurality of data are mixed for one projection because of having a plurality of vertices. Therefore, in this case, the frequency distribution is obtained by adopting the vertex having the highest height from among the plurality of vertices belonging to the same microprotrusion as the protuberance.

When each microprotrusion in the microprotrusion group has the same height H and the microprotrusions are regularly arranged with a constant period, the adjacent protrusion interval d matches the period p of the microprotrusion array. d _max = p. Therefore, the condition that can exhibit the antireflection effect is d _max = p ≦ Λ _min , and the antireflection effect can be exhibited for light having a wavelength longer than the period p of the microprojection array (for example, see Japanese Patent Application Laid-Open (JP-A)). No. 50-70040, Japanese Patent No. 4632589, and Japanese Patent No. 4270806). Therefore, for example, in order to obtain an antireflection effect for all wavelengths in the visible light band, when the shortest wavelength in the visible light band is 380 nm, the period of the microprojection array may be set to 380 nm or less. The height H of the microprojections is preferably 0.2 times or more of the longest wavelength Λ _max among the wavelengths for obtaining the antireflection effect (H ≧ 0.2 × Λ _max ). Therefore, for example, in order to obtain an excellent antireflection effect for all wavelengths in the visible light band, when the longest wavelength in the visible light band is 780 nm, H ≧ 0.2 × 780 nm = 156 nm. Is preferred.

When the protrusions are irregularly arranged, the maximum value d _max = d _AVG + 2σ of the distance d between adjacent protrusions obtained as described above needs to satisfy d _max ≦ Λ _min. It is preferable that the average value H _AVG of the height H of the protrusion satisfies H _AVG ≧ 0.2 × Λ _max . For example, d _max = d _AVG + 2σ ≦ 380 nm may be set so that the antireflection effect can be obtained for all wavelengths in the visible light band. A preferable condition that can more reliably exhibit an antireflection effect for all wavelengths in the visible light band is d _max ≦ 300 nm, and a more preferable condition is d _max ≦ 200 nm. Further, for the reasons such as the expression of the antireflection effect and the securing of the isotropic (low angle dependency) of the reflectance, d _max ≧ 50 nm is usually satisfied, and preferably d _max ≧ 100 nm. The projections for the height H, in order to exhibit a sufficient anti-reflection effect, the shortest wavelength in the wavelength band of light to improve the antireflection when a lambda _max, the H _AVG ≧ 0.2 × Λ _max it is preferred, is preferably _{H AVG} ≧ 0.2 × 780nm = _156nm in order to can achieve an antireflection effect for all wavelengths of visible light _band, it is more preferably a _{H AVG} ≧ 170 nm. The height _{HAVG of the} protrusion is usually 350 nm or less from the viewpoint of the antireflection effect. Further, the height distribution of the protrusions is usually 50 to 350 nm.

Preferably fine aspect ratio of projections (average projection height _{H AVG} / average adjacent protrusions distance _{d AVG)} is 0.8 to 2.5, further more preferably 0.8 to 2.1.

  The thickness of the fine uneven layer (T in FIG. 1) may be adjusted as appropriate, but is preferably 3 μm to 30 μm, and more preferably 5 μm to 10 μm. In the present invention, the thickness T of the fine concavo-convex layer is defined as the thickness from the interface of the fine concavo-convex layer to the transparent base material to the top of the highest minute protrusion.

  In this invention, a fine uneven | corrugated layer consists of the hardened | cured material of a resin composition. In the present invention, the cured product refers to a material that has become hard through a chemical reaction, and the curability refers to a property that becomes hard through a chemical reaction. Hereinafter, the physical properties of the cured product of the resin composition will be described, and then the composition of the resin composition will be described.

(Hardened resin composition)
The cured product of the resin composition is obtained by curing a resin composition described later by the action of light and / or heat. By the manufacturing method described later, the cured product can be made into a fine uneven layer provided with a predetermined fine uneven shape.

  In the present invention, the cured product of the resin composition has a storage elastic modulus (E ′) at 25 ° C. of 300 MPa or less. By setting E ′ to 300 MPa or less, the minute protrusions are deformed by the pressure during wiping, and the dirt that has entered the gap between the minute protrusions can be removed by dry wiping. Among them, the storage elastic modulus (E ′) is preferably 1 to 250 MPa, and more preferably 1 to 100 MPa.

  In the present invention, the ratio of the loss elastic modulus (E ″) to the storage elastic modulus (E ′) at 25 ° C. of the cured product of the resin composition (tan δ (= E ″ / E ′) loss tangent) is 0. .2 or less. By setting the loss tangent to 0.2 or less, the minute protrusions deformed at the time of wiping are elastically restored and easily return to the original shape. Thereby, the plastic deformation and sticking of the protrusions are suppressed, and the dirt can be wiped off by dry wiping without deteriorating the antireflection performance. Among them, tan δ is preferably 0.18 or less.

In the present invention, the storage elastic modulus (E ′) and the loss elastic modulus (E ″) are measured by the following method in accordance with JIS K7244.
First, a resin composition for forming a fine uneven layer is sufficiently cured by irradiating ultraviolet rays having an energy of 2000 mJ / cm ² for 1 minute or more, and does not have a substrate and fine uneven shapes, a thickness of 1 mm, a width A single film having a length of 5 mm and a length of 30 mm is used.
Next, by applying a cyclic external force of 25 g at 10 Hz in the length direction of the cured product of the resin composition at 25 ° C. and measuring dynamic viscoelasticity, E ′ and E ″ at 25 ° C. are obtained. As a measuring device, for example, Rhegel E400 manufactured by UBM can be used.

The cured product of the resin composition preferably has a contact angle of n-hexadecane of 30 ° or less or a contact angle of oleic acid of 25 ° or less on the surface of the cured product. Even if the oily dirt adhering to the surface of the fine concavo-convex layer is not completely wiped off because the surface of the cured product of the resin composition has the lipophilicity as described above, the surface of the fine concavo-convex layer is not removed. Since it spreads thinly, the dirt becomes inconspicuous and visibility after wiping is improved.
Moreover, it is preferable that the contact angle of the water on the surface of the said hardened | cured material is 70 degree | times or more from the point of the wiping property of the surface of the hardened | cured material of the said resin composition.

In the present invention, the contact angle is measured as follows.
First, a resin composition for a fine concavo-convex layer is applied on a transparent substrate, and cured by irradiating ultraviolet rays with an energy of 2000 mJ / cm ² for 1 minute or longer to form a coating film having no fine concavo-convex shape. To do. Adhere horizontally to a black acrylic plate with an adhesive layer with the coating side facing up. Next, a droplet of 1.0 μL of a solvent (water, n-hexadecane, or oleic acid) whose contact angle is to be measured was dropped on the fine uneven layer, and the contact angle 10 seconds after the landing was measured. As the measuring device, for example, a contact angle meter DM 500 manufactured by Kyowa Interface Science Co., Ltd. can be used.

In the antireflection article of the present invention, the elastic modulus of the surface of the fine uneven layer is preferably 200 to 500 MPa, more preferably 220 to 400 MPa, from the viewpoint of excellent flexibility.
The maximum indentation depth on the surface of the fine concavo-convex layer is preferably 1.0 to 2.0 μm, and more preferably 1.2 to 1.8 μm from the viewpoint of being easily deformable and excellent in wiping properties.
In addition, the elastic recovery rate of the surface of the fine concavo-convex layer is preferably 80% or more, and more preferably 85 to 98% from the viewpoint that the plastic deformation is small and wiping marks are not easily generated.

In the present invention, the elastic modulus, the maximum indentation depth, and the elastic recovery rate are measured as follows.
An indenter is pressed into the surface of the anti-reflective article on the fine uneven layer side under the following specific conditions, and the elastic modulus, maximum indentation depth, and elastic recovery rate of the film surface can be measured.
As the measuring apparatus, for example, PICODENER HM-500 manufactured by Fischer Instruments can be used.
<Measurement conditions>
・ Loading speed 1mN / 10 seconds ・ Holding time 10 seconds ・ Load unloading speed 1 mN / 10 seconds ・ Indenter Vickers ・ Measurement temperature 25 ℃

(Resin composition)
As the resin composition for the fine uneven layer, a resin composition containing a thermosetting component and / or a photocurable component and having the above physical properties after curing is used. Especially, it is preferable that it is a photocurable resin composition containing a photocurable component.
As said photocurable component, it is preferable that it is a composition containing the compound which has an ethylenically unsaturated bond, and it is more preferable that it is a composition containing (meth) acrylate.
The photocurable resin composition should just contain the said photocurable component at least, and may contain another component as needed.
Moreover, it is preferable that the said resin composition contains the compound which has a C10 or more long-chain alkyl group from the point that the lipophilicity of hardened | cured material surface improves and a microprotrusion is excellent in a softness | flexibility.
Hereinafter, each component in the composition containing (meth) acrylate which is preferably used as the photocurable component will be described in order.

(1) (Meth) acrylate (meth) acrylate is a monofunctional (meth) acrylate having one (meth) acryloyl group in one molecule, but two or more (meth) acryloyl groups in one molecule It may be a polyfunctional acrylate having a monofunctional (meth) acrylate and a polyfunctional (meth) acrylate.
Among these, it is preferable to use a monofunctional (meth) acrylate and a polyfunctional (meth) acrylate in combination from the viewpoint that the cured product satisfies the above physical properties and the microprotrusions have both flexibility and elastic resilience.

  Specific examples of monofunctional (meth) acrylates include, for example, methyl (meth) acrylate, hexyl (meth) acrylate, decyl (meth) acrylate, allyl (meth) acrylate, benzyl (meth) acrylate, butoxyethyl (meth) acrylate , Butoxyethylene glycol (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycerol (meth) acrylate, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) ) Acrylate, 2-hydroxypropyl (meth) acrylate, isobornyl (meth) acrylate, isodexyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate Relate, 2-methoxyethyl (meth) acrylate, methoxyethylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, stearyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, biphenyloxyethyl acrylate, bisphenol A diglycidyl (meth) acrylate, biphenylyloxyethyl (meth) acrylate, ethylene oxide modified biphenylyloxyethyl (meth) acrylate, bisphenol A epoxy (meth) acrylate, and the like. Among these, a monofunctional (meth) acrylate having a long-chain alkyl group having 10 or more carbon atoms is preferable from the viewpoint that the lipophilicity of the cured product surface is improved and the microprotrusions are excellent in flexibility. It is even more preferable that it contains at least one of tridecyl (meth) acrylate and dodecyl (meth) acrylate. These monofunctional (meth) acrylic acid esters can be used alone or in combination of two or more. In addition, when using the monofunctional (meth) acrylate which has a C10 or more long-chain alkyl group, it has the characteristic of the compound which has a C10 or more long-chain alkyl group mentioned later.

  It is preferable that content of monofunctional (meth) acrylate is 5-40 mass% with respect to the total solid of a photocurable resin composition, and it is more preferable that it is 10-30 mass%.

  Specific examples of the polyfunctional acrylate include, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene di (meth) acrylate, hexanediol di (meth) acrylate, and polyethylene glycol di (meth) acrylate. Bisphenol A di (meth) acrylate, tetrabromobisphenol A di (meth) acrylate, bisphenol S di (meth) acrylate, butanediol di (meth) acrylate, di (meth) acrylate phthalate, ethylene oxide modified bisphenol A di ( (Meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, tri (Acryloxyethyl) isocyanurate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, urethane tri (meth) acrylate, ester tri (meth) acrylate, urethane hexa (meth) acrylate, ethylene oxide modified tri Examples include methylolpropane tri (meth) acrylate. Among these, from the viewpoint that the microprotrusions are excellent in flexibility and restorability, it is preferable to use a polyfunctional (meth) acrylate containing an alkylene oxide, more preferably an ethylene oxide modified polyfunctional (meth) acrylate, and an ethylene oxide modified Even more preferably, at least one of bisphenol A di (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, and polyethylene glycol di (meth) acrylate is included.

  It is preferable that content of the said polyfunctional (meth) acrylate is 10-95 mass% with respect to the total solid of a photocurable resin composition, and it is more preferable that it is 15-90 mass%.

(2) Compound having a long-chain alkyl group having 10 or more carbon atoms The resin composition used in the present invention has 10 or more carbon atoms because the lipophilicity of the cured product surface is improved and the microprojections are excellent in flexibility. A compound having a long-chain alkyl group is preferably contained, and a compound having a long-chain alkyl group having 12 or more carbon atoms is more preferably contained.
Specific examples of the compound having a long chain alkyl group having 10 or more carbon atoms include compounds having decane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, and the like. Moreover, unless the effect of this invention is impaired, you may have a substituent further. Specific examples of the substituent include halogen atoms such as fluorine, chlorine and bromine, hydroxyl groups, carboxy groups, amino groups and sulfo groups, as well as ethylenically unsaturated double bonds such as vinyl groups and (meth) acryloyl groups. Groups and the like. Especially, it is preferable to have an ethylenically unsaturated double bond from a point provided with photocurability, and it is more preferable to have a (meth) acryloyl group.
In addition, when the compound which has a C10 or more long-chain alkyl group has a (meth) acryloyl group, the said compound may correspond also to the said (meth) acrylate.

  When using a compound having a long-chain alkyl group having 10 or more carbon atoms, the content of the compound is preferably 5 to 30% by mass with respect to the total solid content of the photocurable resin composition. More preferably, it is 20 mass%.

  The photo-curable resin composition preferably used in the present invention can easily adjust the storage modulus and loss tangent of the cured product to the above-mentioned predetermined ranges, and can easily be adjusted to be oleophilic, thereby obtaining excellent dry wiping properties. It is particularly preferable that at least a (meth) acrylate having a long-chain alkyl group having 10 or more carbon atoms and an ethylene oxide-modified polyfunctional (meth) acrylate are contained. Especially, it is preferable that the content rate of the (meth) acrylate which has a C10 or more long-chain alkyl group is 5-30 mass parts with respect to 100 mass parts of ethylene oxide modified polyfunctional (meth) acrylate. More preferably, it is -15 mass parts.

(3) Photopolymerization initiator In order to initiate or accelerate the curing reaction of the (meth) acrylate, a photopolymerization initiator may be appropriately selected and used as necessary. Specific examples of the photopolymerization initiator include, for example, bisacylphosphinoxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 2,2-dimethoxy-1. , 2-Diphenylethane-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-methyl-1- [4- (Methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-hydroxy-2-methyl-1-phenyl -Propane-1-ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, phenylbis (2,4,6-trimethylbenzene) Benzoyl) - phosphine oxide, phenyl (2,4,6-trimethylbenzoyl) ethyl phosphinic acid and the like. These can be used alone or in combination of two or more.

  When using a photoinitiator, content of the said photoinitiator is 0.8-20 mass% normally with respect to the total solid of a photocurable resin composition, and 0.9-10 mass% It is preferable that

(4) Antistatic agent In this invention, it is preferable to contain an antistatic agent in the said resin composition. By containing the antistatic agent, it is possible to prevent the dirt from adhering to the surface of the fine concavo-convex layer, and the dirt is easily removed during wiping.
The antistatic agent can be appropriately selected from conventionally known ones. Specific examples of the antistatic agent include, for example, various cationic compounds having a cationic group such as a quaternary ammonium salt, a pyridinium salt, and a primary to tertiary amino group, a sulfonate group, a sulfate ester base, and a phosphate ester. Bases, anionic compounds having an anionic group such as phosphonic acid bases, amphoteric compounds such as amino acid series and aminosulfate ester series, nonionic compounds such as amino alcohol series, glycerin series and polyethylene glycol series, tin and titanium alkoxides And metal chelate compounds such as acetylacetonate salts thereof. Of these, cationic compounds are preferred, cationic compounds having a tertiary amino group are more preferred, and trialkylamines such as N, N-dioctyl-1-octaneamine are even more preferred.

  When using an antistatic agent, content of the said antistatic agent is 1-20 mass% normally with respect to the total solid of a photocurable resin composition, and it is preferable that it is 2-10 mass%.

(5) Solvent In the present invention, the resin composition may use a solvent from the viewpoint of imparting coatability and the like. In the case of using a solvent, the solvent does not react with each component in the composition, and can be appropriately selected from solvents that can dissolve or disperse each component. Specific examples of such solvents include hydrocarbon solvents such as benzene and hexane, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, tetrahydrofuran, 1,2-dimethoxyethane, propylene glycol monoethyl ether ( PGME) ether solvents such as chloroform and dichloromethane, halogenated alkyl solvents such as methyl acetate, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate and other amide solvents such as N, N-dimethylformamide And sulfoxide solvents such as dimethyl sulfoxide, anone solvents such as cyclohexane, and alcohol solvents such as methanol, ethanol, and propanol, but are not limited thereto. Not to. Moreover, the solvent used for a resin composition may be used individually by 1 type, and the mixed solvent of two or more types of solvents may be sufficient as it.

  The ratio of the solid content with respect to the total amount of the resin composition is preferably 20 to 70% by mass, and more preferably 30 to 60% by mass. In addition, in this invention, solid content represents all components other than the solvent in a resin composition.

(6) Other components The resin composition for fine concavo-convex layers used in the present invention may further contain other components as long as the effects of the present invention are not impaired. Other components include, for example, a surfactant for adjusting wettability, a silane coupling agent for improving adhesion, a stabilizer, an antifoaming agent, a repellency inhibitor, an antioxidant, an anti-aggregation agent, and a viscosity. Preparation agents, release agents and the like can be mentioned.

<Other layers>
The antireflection article of the present invention may further have other layers as long as the effects of the present invention are not impaired. The surface side of the transparent substrate that does not have the fine uneven layer may have various conventionally known layers used for optical film applications. For example, a conventionally known single layer or multilayer antireflection layer, a layer imparting antiglare property (or antireflection) by light diffusion, a conventionally known hard coat layer for preventing scratches, and the like can be mentioned.

  In the antireflection article of the present invention, the transmittance in the visible light region is preferably 80% or more, and more preferably 90% or more. Here, the transmittance of the antireflective article can be measured by JIS K7361-1 (a test method for the total light transmittance of plastic-transparent material).

<Use of anti-reflective article>
The antireflection article according to the present invention can be used for various articles in addition to the image display device described later.
For example, shop windows, exhibition windows for museum exhibits; display windows for clocks and other measuring instruments; various printed materials such as road signs and posters; vehicles such as automobiles and aircraft; and windows for various buildings Visibility can be improved by arranging it on the front surface or both surfaces. It can also be used as a window material for various optical devices such as glasses, cameras, telescopes, microscopes, and various illumination devices.

In the above-described embodiment, the wavelength band of the electromagnetic wave for preventing reflection has been described as the visible light band, but the present invention is not limited to this, and the wavelength band of the electromagnetic wave for preventing reflection is infrared, ultraviolet, or the like. The wavelength band other than visible light may be set. In that case, in each of the above conditional expressions, the shortest wavelength Λ _min and the longest wavelength Λ _max of the wavelength band of the electromagnetic wave are respectively set to the shortest wavelength and the longest wavelength for which an antireflection effect is desired in the wavelength band of infrared rays, ultraviolet rays, etc. It is sufficient to set each. For example, when it is desired to prevent reflection in the infrared band where the shortest wavelength Λ _min is 850 nm, the distance d between adjacent protrusions (or its maximum value d _max ) may be designed to be 850 nm or less, for example, d _max = 800 nm.

<Method for producing antireflection article>
What is necessary is just to select suitably the manufacturing method of the reflection preventing article of this invention from the conventionally well-known method of forming a fine uneven | corrugated layer on a transparent base material.
For example, first, a resin composition for forming a fine concavo-convex layer is applied onto a transparent substrate, and the concavo-convex shape of the original substrate for forming a fine concavo-convex layer having a desired fine concavo-convex shape is formed into a coating film of the resin composition. Thereafter, the resin composition is cured to form a fine concavo-convex layer, and then peeled off from the fine concavo-convex layer forming original plate. The method for curing the resin composition can be appropriately selected according to the type of the resin composition.

The master for forming the fine uneven layer is not particularly limited as long as it is not deformed and worn when repeatedly used, and may be made of metal or resin, Metal is preferably used. This is because it is excellent in deformation resistance and wear resistance.
The surface having the fine concavo-convex shape of the original plate for forming the fine concavo-convex layer is not particularly limited, but is preferably made of aluminum from the viewpoint of being easily oxidized and easily processed by anodization.
Specifically, the master for forming the fine uneven layer is, for example, a high-purity aluminum by sputtering or the like directly on the surface of a metal base material such as stainless steel, copper, or aluminum, or through various intermediate layers. A layer is provided, and the aluminum layer is formed with an uneven shape. Prior to providing the aluminum layer, the surface of the base material may be made into a super mirror surface by an electrolytic composite polishing method in which electrolytic elution action and abrasion action by abrasive grains are combined.
As a method of forming a fine uneven shape on the original plate for forming a fine uneven layer, for example, an anodic oxidation step of forming a plurality of fine holes on the surface of the aluminum layer by an anodic oxidation method, and etching the aluminum layer A first etching step for forming a tapered shape in the opening of the microhole, and a second for enlarging the hole diameter of the microhole by etching the aluminum layer at an etching rate higher than the etching rate of the first etching step. It can be formed by sequentially repeating the etching process.
When forming a fine concavo-convex shape, a desired shape can be obtained by appropriately adjusting the purity (amount of impurities), crystal grain size, anodizing treatment and / or etching conditions of the aluminum layer. . In the anodizing treatment, more specifically, by controlling the liquid temperature, the voltage to be applied, the time for the anodizing, etc., fine holes are formed into shapes corresponding to the target depth and the shape of the fine protrusions, respectively. be able to.
In this way, in the original plate for forming a fine concavo-convex layer, a large number of fine holes whose pore diameter gradually decreases in the depth direction are densely produced. In the fine concavo-convex layer manufactured using the fine concavo-convex layer forming original plate, fine concavo-convex portions having a small protrusion group that gradually decreases in diameter as it approaches the top corresponding to the fine holes are formed. The cross-sectional area occupancy rate of the material portion forming the fine unevenness in the horizontal cross section when it is assumed to be cut in a horizontal plane perpendicular to the depth direction of the fine unevenness approaches the deepest portion direction from the top of the fine unevenness. As a result, a fine concavo-convex shape that gradually increases gradually is formed.

Further, the shape of the original plate for forming a fine uneven layer is not particularly limited as long as it can shape a desired shape. For example, it may be a flat plate shape or a roll shape. However, it is preferable to use a roll-shaped mold (hereinafter sometimes referred to as a “roll mold”) from the viewpoint of improving productivity.
As a roll mold used in the present invention, for example, as a base material, a cylindrical metal material is used, and an aluminum layer provided directly or via various intermediate layers on the peripheral side surface of the base material, As described above, there may be mentioned those in which fine irregularities are produced by repeating anodizing treatment and etching treatment.

In FIG. 6, when a photocurable resin composition is used as the resin composition for forming the fine uneven layer and a roll mold is used as the original plate for forming the fine uneven layer, the fine uneven layer is formed on the transparent substrate. An example of the method is shown.
In the method shown in FIG. 6, in the resin supplying step, an uncured and liquid photocurable resin composition is applied to the transparent base material 1 in the form of a strip with a die 11 to form a microprojection-shaped receiving layer 2 ′. To do. In addition, about application | coating of a photocurable resin composition, not only the case by the die | dye 11 but various methods are applicable. Subsequently, the pressing roller 13 presses and presses the transparent base material 1 against the peripheral side surface of the roll mold 12 which is a master for forming a fine uneven layer, thereby bringing the receiving layer 2 ′ into close contact with the transparent base material 1, A fine concavo-convex recess formed on the peripheral side surface of the roll mold 12 is sufficiently filled with the photocurable resin composition constituting the receiving layer 2 ′. In this state, the photocurable resin composition is cured by irradiation with ultraviolet rays, whereby the fine uneven layer 2 is produced on the surface of the transparent substrate 1. Subsequently, the transparent substrate 1 is peeled off from the roll die 12 through the peeling roller 14 together with the hardened fine uneven structure 2. If necessary, an adhesive layer or the like is produced on the transparent substrate 1 and then cut to a desired size to produce the antireflection article 1. As a result, the anti-reflective article is formed by sequentially molding the fine concavo-convex shape produced on the peripheral side surface of the roll mold 12 which is the original plate for forming the fine concavo-convex layer on the long transparent base material 1 made of a roll material, and efficiently. Mass production.

  In the above-described embodiment, the case where a film-shaped antireflection article is produced by a forming process using a roll mold is described. However, the present invention is not limited to this, and the transparent substrate according to the shape of the antireflection article is used. Depending on the shape of the substrate, for example, when creating an antireflection article by processing a flat plate or a sheet using a mold for molding with a specific curved shape, a step relating to the molding process, a master for forming a microprojection structure Can be appropriately changed according to the shape of the transparent substrate according to the shape of the antireflection article.

[Image display device]
The image display device according to the present invention includes the antireflection article according to the present invention on at least one side of a display panel.

As shown in FIG. 2, the image display device 20 of the present invention includes the antireflection article 10 according to the present invention on at least one surface side of the display panel 4. The antireflection article 10 may be directly bonded to the display panel 4, and has another member between the antireflection article 10 and the display panel 4 as long as the effects of the present invention are not impaired. Also good. As said other member, a well-known touch panel member etc. are mentioned, for example.
The image display device of the present invention may be a device having only a display function (for example, an LCD monitor, a CRT monitor, etc.), but a device having a display function as a part of the function of the device is also applicable. For example, a portable information terminal, a car navigation system, or the like.

  Since the image display device of the present invention can wipe off dirt by dry wiping without degrading the antireflection performance, it can maintain excellent antireflection properties. Therefore, in particular, it can be suitably used also in an image display device provided with a touch panel member, which often touches the display device surface directly with a finger.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

(Production Example 1 Preparation of a fine uneven layer forming original)
A rolled aluminum plate having a purity of 99.50% is polished so that its surface has an irregular shape with a 10-point average roughness Rz of 30 nm and a period of 1 μm, and then formed in an electrolyte solution of 0.02 M oxalic acid aqueous solution. Anodization was performed for 120 seconds under conditions of a voltage of 40 V and 20 ° C. Next, as a first etching process, an etching process was performed for 60 seconds with the electrolytic solution after anodization. Subsequently, as the second etching treatment, a pore size treatment was performed with a 1.0 M phosphoric acid aqueous solution for 150 seconds. Furthermore, the said process was repeated and these were added and implemented 5 times in total. As a result, an anodized aluminum layer having fine irregularities formed on the aluminum substrate was formed. Finally, a fluorine-based mold release agent was applied and the excess mold release agent was washed to obtain an original plate for forming a fine uneven layer. In addition, the fine uneven shape formed in the aluminum layer has an average distance between adjacent micropores of 100 nm, an average depth of 200 nm, and a large number of micropores that are gradually reduced in the depth direction. It was a shape.

(Production Example 2 Preparation of Resin Composition A for Forming Fine Uneven Layer)
The following components were mixed, and a resin composition A for forming a fine uneven layer having a solid content of 45% by mass was prepared using methyl ethyl ketone and methyl isobutyl ketone as diluent solvents.
<Composition of Resin Composition A>
-Ethylene oxide modified (EO modified) bisphenol A diacrylate 55 parts by mass-EO modified trimethylolpropane triacrylate 35 parts by mass-Tridecyl acrylate 5 parts by mass-Dodecyl acrylate 5 parts by mass-Diphenyl (2,4,6-trimethoxy Benzoyl) phosphine oxide (Lucirin TPO) 1 part by mass

(Production Example 3 Preparation of Resin Composition B for Forming Fine Uneven Surface)
The following components were mixed, and a resin composition B for forming a fine uneven layer having a solid content of 45% by mass was prepared using methyl ethyl ketone and methyl isobutyl ketone as diluent solvents.
<Composition of Resin Composition B>
-EO-modified bisphenol A diacrylate 50 parts by mass-EO-modified trimethylolpropane triacrylate 30 parts by mass-tridecyl acrylate 5 parts by mass-dodecyl acrylate 5 parts by mass-methyl methacrylate 5 parts by mass-hexyl methacrylate 5 parts by mass-diphenyl (2 , 4,6-Trimethoxybenzoyl) phosphine oxide (Lucillin TPO) 1 part by mass

(Comparative Production Example 1 Preparation of Resin Composition C for Forming Fine Uneven Layer)
The following components were mixed, and a resin composition C for forming a fine uneven layer having a solid content of 45% by mass was prepared using methyl ethyl ketone and methyl isobutyl ketone as diluent solvents.
<Composition of Resin Composition C>
-EO-modified bisphenol A diacrylate 30 parts by mass-EO-modified trimethylolpropane triacrylate 20 parts by mass-dodecyl acrylate 50 parts by mass-diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide (lucillin TPO) 1 part by mass

(Comparative Production Example 2 Preparation of Resin Composition D for Forming Fine Uneven Surface Layer)
The following components were mixed, and a resin composition D for forming a fine uneven layer having a solid content of 45% by mass was prepared using methyl ethyl ketone and methyl isobutyl ketone as diluent solvents.
<Composition of Resin Composition D>
Pentaerythritol triacrylate 15 parts by mass 2,4,4-trimethylhexamethylene diisocyanate 15 parts by mass Polyethylene glycol diacrylate 70 parts by mass Diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide (lucillin TPO) 1 Parts by mass

Example 1
The fine concavo-convex layer forming resin composition A obtained in Production Example 2 is covered with the fine concavo-convex surface of the fine concavo-convex layer forming original plate obtained in Production Example 1, and the thickness of the fine concavo-convex layer after curing is 20 μm. After coating and filling so as to become a transparent base material, a triacetyl cellulose film (TAC) (manufactured by Fuji Film Co., Ltd.) having a thickness of 80 μm is laminated from an oblique direction, and then the laminated body is a rubber roller. And crimped with a load of 10 N / cm ² . After confirming that the uniform composition was applied to the entire original plate, ultraviolet rays were irradiated from the transparent substrate side with an energy of 2000 mJ / cm ² to cure the resin composition for forming a fine uneven layer. Then, it peeled from the original plate and obtained the antireflection article A of Example 1.

(Example 2)
In Example 1, instead of the resin composition A for forming a fine uneven layer, an antireflection article was prepared in the same manner as in Example 1 except that the resin composition B for forming a fine uneven layer obtained in Production Example 2 was used. B was obtained.

(Comparative Example 1)
In Example 1, in place of the resin composition A for forming a fine uneven layer, the antireflection was applied in the same manner as in Example 1 except that the resin composition C for forming a fine uneven layer obtained in Comparative Production Example 1 was used. Article C was obtained.

(Comparative Example 2)
In Example 1, in place of the resin composition A for forming a fine uneven layer, the antireflection was applied in the same manner as in Example 1 except that the resin composition D for forming a fine uneven layer obtained in Comparative Production Example 2 was used. Article D was obtained.

[Evaluation]
<Measurement of storage elastic modulus (E ′) and tan δ>
Each of the resin compositions A to D for forming a fine uneven layer is sufficiently cured by irradiating ultraviolet rays having an energy of 2000 mJ / cm ² for 1 minute or more, and does not have a substrate and fine uneven shapes, a thickness of 1 mm, a width Test single films A to D each having a length of 5 mm and a length of 30 mm were obtained.
Next, in accordance with JIS K7244, by applying a periodic external force of 25 g at 25 Hz at 10 Hz in the length direction of the cured product of the resin composition, and measuring the dynamic viscoelasticity, the storage elasticity at 25 ° C. The modulus E ′ and the loss modulus E ″ were obtained. Further, tan δ was calculated from the results of E ′ and E ″. As a measuring device, Rheogel E400 made by UBM was used. The results are shown in Table 1.

<Measurement of contact angle>
The coating composition which does not have a fine uneven | corrugated shape by apply | coating the resin composition AD for fine uneven | corrugated layer formation on a triacetyl cellulose film, and making it harden | cure by irradiating the ultraviolet-ray of energy of 2000 mJ / cm < ² > for 1 minute or more. Formed. The surface of the coating film side was used as the upper surface, and a droplet of 1.0 μL of water was dropped on the surface adhered to a black acrylic plate with an adhesive layer, and the contact angle of water 5 seconds after the landing was measured. The contact angle of each solvent was measured using n-hexadecane and oleic acid, respectively, instead of water. The results are shown in Table 1.
As a measuring device, a contact angle meter DM 500 manufactured by Kyowa Interface Science Co., Ltd. was used.

<Measurement of elastic modulus, maximum indentation depth, elastic recovery rate>
The indentation is pushed into the surface of the fine uneven layer side of the antireflection articles A to D obtained in Examples 1 and 2 and Comparative Examples 1 and 2 under the following specific conditions, the elastic modulus of the surface of the fine uneven layer, the maximum push Depth and elastic recovery were measured. The measuring device used was PICODENER HM-500 manufactured by Fisher Instruments. The results are shown in Table 1.
<Measurement conditions>
・ Loading speed 1mN / 10 seconds ・ Holding time 10 seconds ・ Load unloading speed 1 mN / 10 seconds ・ Indenter Vickers ・ Measurement temperature 25 ℃

<Fingerprint wiping test>
The anti-reflective articles A to D obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were attached to a black acrylic plate with an adhesive layer with the surface of the fine uneven layer side as the upper surface, and then the finger was pressed to print the fingerprint. Attached. Thereafter, the fingerprint was wiped dry with Zavina Minimax (Fuji Chemical). Dry wiping was performed 10 times with a force of about 3 kg / cm ² , and the appearance after wiping was evaluated. The results are shown in Table 1.
[Fingerprint wiping test evaluation criteria]
A: Fingerprint stains are not visible.
B: A slight color change is visually recognized on the fingerprint adhesion mark.
C: Fingerprints are hardly wiped off.

<Slidability test>
The anti-reflective articles A to D obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were attached to a black acrylic plate with an adhesive layer with the fine uneven layer side surface as the upper surface, and then Xavina Minimax (Fuji (Chemical) was rubbed 10 times with a force of about 3 kg / cm ² . The visibility after 1 minute of rubbing was evaluated according to the following criteria. The results are shown in Table 1.
[Slidability test evaluation criteria]
A: Scratch marks are not visually recognized.
B: The tint has a slight change in color.
C: Scratch marks are clearly cloudy.

[Summary of results]
Example 1 and Example which have a fine uneven | corrugated layer formed using the hardened | cured material of the resin composition whose storage elastic modulus (E ') is 300 Mpa or less and tan-delta is 0.2 or less in 25 degreeC. The anti-reflective article 2 was able to wipe fingerprints even with dry wiping, and no wiping trace was confirmed. In Comparative Example 1 where tan δ is 0.69, it is presumed that fine protrusions caused plastic deformation or stacking occurred due to the pressure during wiping. In Comparative Example 2 having a storage elastic modulus E ′ of 330 MPa, the fine protrusions were not easily deformed, and the fingerprint stain could not be sufficiently removed by dry wiping.

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Fine uneven | corrugated layer 2 'Receptive layer 3 Minute protrusion 4 Display panel 10 Antireflection article 11 Die 12 Roll metal mold 13 Press roller 14 Peeling roller 20 Image display apparatus

Claims (4)

An antireflective article comprising a fine concavo-convex layer comprising a cured product of the resin composition on at least one surface side of the transparent base material and having a fine concavo-convex shape on the surface opposite to the transparent base material,
The surface of the fine concavo-convex layer has a fine concavo-convex shape provided with a group of fine protrusions formed by a collection of fine protrusions, and the microprotrusions have the shortest wavelength of the wavelength band of light for preventing reflection as Λ _min . When the maximum value of the distance d between adjacent protrusions of the protrusion is _dmax ,
d _max ≦ Λ _min
And the cross-sectional area occupancy rate of the material portion forming the microprojection in the horizontal cross section when it is assumed that the microprojection is cut in a horizontal plane perpendicular to the depth direction of the microprojection is It has a structure that increases gradually and gradually as it approaches the deepest part from the top,
The storage elastic modulus (E ′) at 25 ° C. of the cured product of the resin composition is 1 MPa or more and 300 MPa or less, and the loss elastic modulus with respect to the storage elastic modulus (E ′) at 25 ° C. of the cured product of the resin composition. A ratio of (E ″) (tan δ (= E ″ / E ′)) is 0.2 or less, an antireflection article,   The antireflection article according to claim 1, wherein the contact angle of n-hexadecane is 30 degrees or less or the contact angle of oleic acid is 25 degrees or less on the surface of the cured product of the resin composition.   The antireflection article according to claim 1 or 2, wherein the resin composition contains a compound having a long-chain alkyl group having 10 or more carbon atoms.   An image display device comprising the antireflection article according to any one of claims 1 to 3 on at least one surface side of the display panel.