JP2015184440A - Antireflection article and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antireflection article designed such that soil on its surface can easily be wiped regardless of wiping with water or dry-wiping and nebula after wiping is inhibited.SOLUTION: An antireflection object is formed of a hardened resin composition, and has a fine rugged layer having on its surface fine recessed and projecting shapes with groups of minute projections, in which the minute projects are arranged in close contact with one another. The minute projections has a relation of d(the maximum value of the interval d between adjacent projections)≤Λ(the shortest wavelength of a wavelength area of light used for antireflection). The minute projections have a tapering structure. The angle of the contact between the fine rugged surface of the fine rugged layer and water is not smaller than 15 degrees. The average of horizontal force measured during 25 to 40 sec after indenter movement when an indenter pressed at a press depth of 55 to 75% of the average projection height Hof each of the minute projections is horizontally moved at a temperature of 25°C or below and at speed of 1 μm/15 sec is 8.0 μN or less in the fine rugged surface.

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 the contaminants cannot be removed by dry wiping.

  On the other hand, in Patent Document 5, in an optical element having an antireflection function provided with a structure having fine irregularities on the surface of a substrate, the structure is attached so that dirt attached to the structure can be removed by wiping. It is described that the elastic modulus of the material forming the body and the aspect ratio of the structure are within a specific range. Patent Document 5 describes that when the surface is wiped off, the structure is deformed, and dirt that has penetrated between the structures is pushed out, so that the dirt can be removed.

Japanese Patent Laid-Open No. 50-70040 Special Table 2003-531962 Japanese Patent No. 4632589 International Publication No. 2012/096322 Pamphlet Japanese Patent No. 5075234

However, as described in Patent Document 5, the present inventors cannot remove dirt even when the elastic modulus of the material forming the structure and the aspect ratio of the structure are within a specific range, It has been found that it may become cloudy after wiping work. Thus, it has been difficult for conventional antireflection articles to have sufficient removal of dirt adhered to the surface while maintaining physical properties in both water wiping and dry wiping.
The present invention has been made in view of the above problems, and can be easily wiped off dirt adhering to the surface in both water wiping and dry wiping, and further anti-reflective article in which white turbidity after wiping work is suppressed. And it aims at providing the image display apparatus provided with the said reflection preventing article.

An antireflective article according to the present invention includes a fine concavo-convex layer having a fine concavo-convex shape on the surface, which is formed of a cured product of a resin composition and includes a group of microprotrusions in which a plurality of microprotrusions are closely arranged. Anti-reflective article,
When the shortest wavelength of the wavelength band of light for preventing reflection is Λ _min and the maximum value of the distance d between adjacent protrusions is d _max ,
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 contact angle of water on the surface of the fine concavo-convex shape side of the fine concavo-convex layer is 15 degrees or more,
The surface of the fine irregularities side of the fine uneven layer, the indenter is pushed by the average projection height H 55% to 75% of the indentation depth of _AVG of the microprojections, a temperature of 25 ° C., of 1 [mu] m / 15 sec The average of the horizontal force measured within 25 to 40 seconds after moving the indenter when moving in the horizontal direction at a speed is 8.0 μN or less.

  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, in any of water wiping and dry wiping, dirt attached to the surface can be easily wiped off, and further, an antireflection article in which white turbidity after wiping is suppressed and an image provided with the antireflection article A display device can be provided.

It is sectional drawing which shows typically an example of the anti-reflective article which concerns on this invention. It is a figure for demonstrating the measuring method of a horizontal force. It is a figure which shows an example of a Delaunay diagram typically. It is the schematic which shows an example of the manufacturing method of the reflection preventing article which concerns on this invention. It is sectional drawing which shows typically an example of the image display apparatus which concerns on this invention.

In this specification, “article” is a concept including aspects such as “plate”, “sheet”, “film” and the like, and the terms “plate”, “sheet”, and “film” are based only on the difference in names. Are not distinguished from each other.
In addition, “film surface (plate surface, sheet surface)” means a target film-like member (plate-like) when the target film-like (plate-like, sheet-like) member is viewed as a whole and globally. It refers to a surface that coincides with the planar direction of the member (sheet-like member).
Further, as used in this specification, the shape and geometric conditions and the degree thereof are specified. For example, terms such as “horizontal”, “orthogonal”, “identical”, length and angle values, etc. are strictly Without being bound by meaning, it should be interpreted including the extent to which similar functions can be expected.
In the present invention, (meth) acryl represents each of acryl or methacryl, (meth) acrylate represents each of acrylate or methacrylate, and (meth) acryloyl represents each of acryloyl or methacryloyl.
Moreover, in this invention, hardened | cured material means what solidified.

An antireflective article according to the present invention includes a fine concavo-convex layer having a fine concavo-convex shape on the surface, which is formed of a cured product of a resin composition and includes a group of microprotrusions in which a plurality of microprotrusions are closely arranged. Anti-reflective article,
When the shortest wavelength of the wavelength band of light for preventing reflection is Λ _min and the maximum value of the distance d between adjacent protrusions is d _max ,
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 contact angle of water on the surface of the fine concavo-convex shape side of the fine concavo-convex layer is 15 degrees or more,
The surface of the fine irregularities side of the fine uneven layer, the indenter is pushed by the average projection height H 55% to 75% of the indentation depth of _AVG of the microprojections, a temperature of 25 ° C., of 1 [mu] m / 15 sec The average of the horizontal force measured within 25 to 40 seconds after moving the indenter when moving in the horizontal direction at a speed is 8.0 μN 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 concavo-convex shape side of the fine concavo-convex layer 2 has a fine concavo-convex shape provided with a group of fine protrusions formed by a collection of microprotrusions 3, and the microprotrusions 3 have a wavelength band of light for preventing reflection. When the shortest wavelength is Λ _min , and 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. The surface of the fine uneven layer 2 on the fine uneven shape side may be simply referred to as a fine uneven surface 2a hereinafter.

Moreover, the anti-reflective article of this invention can wipe off the stain | pollution | contamination adhering to the surface easily in any of water wiping and dry wiping, and the white turbidity after the wiping operation | work is suppressed. In order to sufficiently remove dirt on the surface with a fine concavo-convex structure, the fine protrusions move sufficiently in the wiping direction when wiping is performed, and dirt components that have entered between the fine protrusions due to the behavior of the fine protrusions on the surface. It is considered necessary to make it rise. In addition, the cloudiness after the wiping work is caused by the fact that the minute protrusions move by the wiping work and when the minute protrusions come in contact with each other adjacent minute protrusions through moisture or the like. Conceivable. On the other hand, the present inventors specify the stress (referred to as “horizontal force” in the present invention) when the microprotrusions are moved in the direction of the horizontal plane perpendicular to the depth of the microprotrusions, which is the direction to wipe off the microprotrusions. Focused on doing.
The horizontal force is not the hardness of the material itself, which is determined by the composition of the resin composition constituting the fine concavo-convex layer, but the aspect ratio of the fine concavo-convex shape, or the fine shape of the microprojections that cannot be specified by the aspect ratio, for example, the tip Can be measured as a numerical value taking into account the influence of whether the surface is flat or pointed, and whether the thickness of the microprotrusions is thick or thin. On the other hand, as in the invention described in Patent Document 5, only by specifying the elastic modulus measured using a tensile tester, the material of the article to be measured can be specified, and fine irregularities The difference in shape cannot be taken into account. In addition, the elastic modulus measured by pushing the indenter in the depth direction of the fine concavo-convex layer may be affected by the lower layer, and further, fine differences in the fine concavo-convex shape are not reflected. In the antireflection article of the present invention, the average of the specific horizontal force on the surface of the fine concavo-convex shape side of the fine concavo-convex layer (the fine concavo-convex surface 2a) is set to be equal to or less than the above value, so that each minute protrusion is sufficiently in the wiping direction. It is estimated that it becomes easy to move.
In the present invention, since the water contact angle on the fine uneven surface is more than the lower limit value, since the hydrophilicity is low, even when the microprotrusions adjacent to each other by the wiping work, It is estimated that adhesion between the contacted parts is suppressed. Moreover, in this invention, even if it cannot completely remove the stain | pollution | contamination component adhering to the fine uneven surface by the wiping operation, there exists an effect which makes the said stain | pollution | contamination component wet and spread, and becomes inconspicuous. This is presumably due to the fact that the fine uneven surface has lipophilicity. For these reasons, the antireflective article of the present invention can easily lift the dirt component that has entered between the microprotrusions to the surface by the behavior of the microprotrusions by dry wiping or water wiping, and easily wipe off the dirt adhering to the surface. Even if a small amount of the dirt component adhering to the fine uneven surface remains without being wiped off, the dirt component is not noticeable because it spreads wet, and even when wiping is performed, the minute protrusions are not easily attached to each other For this reason, it is considered that the cloudiness after the wiping operation is suppressed.

<Fine uneven layer>
The fine concavo-convex layer provided in the antireflection article according to the present invention has the fine concavo-convex shape provided on the surface thereof, which is made of a cured product of the resin composition and includes a group of microprojections in which a plurality of microprojections are closely arranged. .
Further, in the above fine irregularities side surface of the fine uneven layer, the indenter is pushed by the average projection height H 55% to 75% of the indentation depth of _AVG of the microprojections, a temperature of 25 ° C., 1 [mu] m / 15 The average of the horizontal force measured within 25 to 40 seconds after moving the indenter when moving in the horizontal direction at a speed of second is 8.0 μN or less. Here, the average projection and shoved in height _H 55% to 75% of the indentation depth of _AVG, the average projection height _H 55% to 75% of the length of _AVG from the tip of the microprojection said microprojection It means that it was pushed in the depth direction of the minute protrusion. Moreover, moving in the horizontal direction means moving in the direction of a horizontal plane perpendicular to the depth direction of the microprotrusions.
In the present invention, the horizontal force on the fine concavo-convex surface is obtained by moving the indenter 5 pushed into the fine concavo-convex surface in the horizontal direction at a temperature of 25 ° C. and a speed of 1 μm / 15 seconds. Sometimes stress is measured. The stress can be measured, for example, with a nanoindenter (for example, TI 950 TriboIndenter manufactured by HYSITRON) using a Barkovic indenter having a tip ridge angle of 105 °. The average horizontal force measured between 25 and 40 seconds after moving the indenter means that the horizontal force is measured 3 to 5 times, and in each measurement, the horizontal force measured between 25 and 40 seconds after moving the indenter. The average value is calculated, and the average value of the average value calculated in each measurement is further calculated. Moreover, the average of the horizontal force within the range of the indentation depth is preferably 6.0 μN or less, and more preferably 5.0 μN or less from the viewpoint of excellent wiping properties. The average lower limit of the horizontal force is not particularly limited as long as the fine uneven shape can be maintained in a stationary state, but it is usually preferably 1.0 μN or more.

In the fine uneven layer, the contact angle of water on the surface of the fine uneven shape side is 15 degrees or more, and more preferably 20 degrees or more. Thereby, even if it is a case where the microprotrusions which mutually adjoin each other by wiping work, adhesion of the contacted parts is suppressed. Moreover, when the contact angle of water is equal to or greater than the lower limit value, it becomes hydrophobic and it becomes easy to remove dirt adhered to the fine uneven layer.
The contact angle of water is not particularly limited, but is preferably less than 90 degrees from the viewpoint of wiping by water wiping.
The water contact angle of the antireflection article according to the present invention is measured as follows.
First, the fine uneven surface side of the fine uneven layer of the antireflective article according to the present invention is placed on the black acrylic plate with the adhesive layer, with the fine uneven surface side as the upper surface. Next, a droplet of 1.0 μL of water, which is a solvent for measuring the contact angle, is dropped on the fine uneven surface, and the contact angle after 1 second of the landing is measured. As the measuring device, for example, a contact angle meter DM 500 manufactured by Kyowa Interface Science Co., Ltd. can be used.

  The shape of the fine protrusions constituting the fine uneven shape of the fine uneven layer is a cut of the material portion forming the fine protrusions in the horizontal cross section when it is assumed that the fine protrusions are cut along a horizontal plane perpendicular to the depth direction of the fine protrusions. What is necessary is just to select suitably from what has a structure where area occupancy increases continuously and gradually as it approaches the deepest part direction from the top part of the said microprotrusion, ie, what has a structure where each microprotrusion tapers. Specific examples of the shape of such microprotrusions include those having a vertical cross-sectional shape such as a semicircular shape, a semi-elliptical shape, a triangular shape, a parabolic shape, a bell shape, and a trapezoidal 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 a schematic diagram of an enlarged photograph in plan view.

  (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. 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.

(5) The frequency distribution of the distance d between adjacent protrusions thus determined is regarded as a normal distribution, and the average value d _AVG and the standard deviation σ _d are determined. In the present invention, the maximum value d _max of the distance d between adjacent protrusions is defined as d _max = d _AVG + 2σ _d and is calculated.

Mean H _AVG and standard deviation sigma _H of the height H of the minute projections can be obtained by applying a procedure similar to the average value d _AVG and standard deviation sigma _d of the aforementioned adjacent protrusions distance d .
First, the 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) to form a histogram. The average value H _AVG of the projection height and the standard deviation σ _H are obtained from the frequency distribution by the histogram. In the histogram of the protrusion height H, in the case of a multi-peak microprotrusion, the plurality of data are mixed for one protrusion due to having a plurality of vertices. 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 at the heel (base) portion as the protrusion height of the microprotrusion.

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, it is necessary that the maximum value d _max = d _AVG + 2σ _{d of the} distance d between adjacent protrusions obtained as described above satisfies d _max ≦ Λ _min . mean _{H AVG} height H of the minute projections _preferably satisfies the _{H AVG} ≧ 0.2 × _{Λ max.} For example, d _max = d _AVG + 2σ _d ≦ 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 370 nm or less from the viewpoint of the antireflection effect. The height distribution of the protrusions is usually 50 to 370 nm.

The aspect ratio (average height H _AVG / average interval d _AVG ) of the microprojections is not particularly limited, but is preferably 1.4 or more, and more preferably greater than 1.5. When the aspect ratio is not less than the lower limit, the antifouling property of the fine uneven surface is improved. This is because when the wiping operation is performed to remove dirt such as fingerprints adhering to the fine concavo-convex surface, if the aspect ratio is equal to or greater than the lower limit value, the fine protrusions are easy to move, and the behavior of the fine protrusions causes the fine protrusions to move between the fine protrusions. This is because it is presumed to be excellent in the action of lifting the dirt component that has entered into the surface. Moreover, when the aspect ratio is not less than the lower limit, the antireflection performance is improved. On the other hand, although not particularly limited, the visibility is poorer as the aspect ratio is larger when dirt is attached. Therefore, the aspect ratio is preferably 2.5 or less.

  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 a surface opposite to the fine concavo-convex surface of the fine concavo-convex layer when one surface of the fine concavo-convex layer is a fine concavo-convex surface as shown in FIG. To the top of the highest minute protrusion of the fine uneven surface. In the present invention, both surfaces of the fine concavo-convex layer may be fine concavo-convex surfaces. It is the distance in the perpendicular direction to the horizontal plane where the top of the highest microprotrusion touches.

A fine uneven | corrugated layer consists of hardened | cured material of a resin composition. The resin composition for the fine uneven layer is preferably a curable resin composition containing at least one selected from a thermosetting component and a photocurable component. 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.

  Although it does not specifically limit as a resin composition for fine uneven | corrugated layers in this invention, The storage elastic modulus (E ') in 25 degreeC of the hardened | cured material of the said resin composition becomes like this. Preferably it is 100 Mpa or more. Is selected and used at 200 MPa or more. The fine protrusions in the fine concavo-convex layer formed using such a resin composition are highly recoverable, and crushing and adhesion of fine protrusions (sticking) are suppressed during dry wiping. The upper limit of the storage elastic modulus at 25 ° C. of the cured product of the resin composition is not particularly limited, but is preferably 1200 MPa or less, more preferably 800 MPa or less, from the viewpoint of the flexibility and wiping property of the microprojections, Even more preferably, it is 400 MPa or less.

In the present invention, the storage elastic modulus (E ′) is 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, E ′ at 25 ° C. is obtained by applying a periodic 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. As the measuring device, for example, Rheogel E400 manufactured by UBM can be used.

Hereinafter, each component in the composition containing (meth) acrylate which is preferably used as the photocurable component will be described in order.
The (meth) acrylate may be a monofunctional (meth) acrylate or a polyfunctional (meth) acrylate, and is a combination of a monofunctional (meth) acrylate and a polyfunctional (meth) acrylate. Also good.

  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, it is easy to make the average of the contact angle of water and the horizontal force within the range specified in the present invention, and from the viewpoint of improving the dirt wiping property, a single chain having a long-chain alkyl group having 10 or more carbon atoms. Functional (meth) acrylate is preferable, and among them, it is more preferable that the number of carbon atoms is 12 or more, and it is even more preferable that at least one of tridecyl (meth) acrylate and dodecyl (meth) acrylate is included. 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.

  Specific examples of the polyfunctional (meth) 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, (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 Examples include trimethylolpropane tri (meth) acrylate. Among these, a polyfunctional (meth) acrylate containing an alkylene oxide is used because the cured product is excellent in flexibility and resilience, and the average of the horizontal force can be easily within the range defined in the present invention. More preferably, ethylene oxide-modified polyfunctional (meth) acrylate is used, ethylene oxide-modified bisphenol A di (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, and polyethylene glycol di (meth) Even more preferably, one or more selected from acrylates are included.

  From the viewpoint of the storage elastic modulus of the cured product of the resin composition and the horizontal force, it is preferable to use polyfunctional (meth) acrylate. Among them, it becomes easy to make the average of the horizontal force within the range defined in the present invention and to make the storage elastic modulus of the cured product within the preferred range, and the microprojections have elastic resilience and flexibility. Therefore, it is preferable to use a polyfunctional (meth) acrylate containing an alkylene oxide, more preferably an ethylene oxide modified polyfunctional (meth) acrylate, an ethylene oxide modified bisphenol A di (meth) acrylate, ethylene. It is even more preferable to include at least one selected from oxide-modified trimethylolpropane tri (meth) acrylate and polyethylene glycol di (meth) acrylate.

In addition, the resin composition has improved oleophilicity on the surface of the cured product, is provided with flexibility, and it is easy to make the average of the contact angle of water and the horizontal force within the range defined in the present invention. Therefore, a compound having a long-chain alkyl group having 10 or more carbon atoms may be contained from the viewpoint of improving the dirt wiping property.
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.

  From the viewpoint of elastic resilience of the microprotrusions, a (meth) acrylate having a hydroxyl group and a polyvalent isocyanate compound may be used in combination. Specific examples of the polyvalent isocyanate compound include, for example, 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4 -Diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis ( Socyanate methyl) cyclohexane, methylcyclohexane diisocyanate, 4,4′-diphenyl ether diisocyanate, 4,4′-diphenyl sulfoxide diisocyanate, 4,4′-diphenylsulfone diisocyanate, 4,4′-biphenyl diisocyanate, and derivatives thereof. It is done.

  In order to start 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.

  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 resin composition 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. Examples thereof include a regulator and a release agent.
The resin composition may further contain an antistatic agent. 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.

It is preferable to adjust the blending ratio of each component in the resin composition so that the average of the contact angle of water and the horizontal force is within the range defined in the present invention.
In the resin composition, the content of the polyfunctional (meth) acrylate is preferably 10 to 99% by mass and more preferably 15 to 90% by mass with respect to the total solid content of the resin composition. preferable.
Especially, it is preferable to contain 35-95 mass% of polyfunctional (meth) acrylate containing an alkylene oxide in the said resin composition with respect to the total solid of the said resin composition, and 40-90 mass% is contained. It is more preferable.
Moreover, it is preferable that content of monofunctional (meth) acrylate in the said resin composition is 0-40 mass% with respect to the total solid of the said resin composition, and it is 5-40 mass%. Is preferable, and it is more preferable that it is 8-30 mass%.
In the resin composition, the content of the polyvalent isocyanate compound is preferably 0 to 30% by mass, preferably 5 to 30% by mass, based on the total solid content of the resin composition. More preferably, it is -20 mass%.
Content of a photoinitiator is 0.8-20 mass% normally with respect to the total solid of the said resin composition, and it is preferable that it is 0.9-10 mass%.
When using an antistatic agent, content of the said antistatic agent is 1-20 mass% normally with respect to the total solid of the said resin composition, and it is preferable that it is 2-10 mass%.
The ratio of the solid content to the total amount of the resin composition including the solvent is preferably 20 to 70% by mass, and more preferably 30 to 60% by mass. In addition, in this invention, solid content represents all the components except a solvent.

<Transparent substrate>
The antireflection article according to the present invention may include a transparent substrate as a support. 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 acetyl cellulose resins such as triacetyl cellulose, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, olefin resins such as polyethylene and polymethylpentene, acrylic resins, Transparent resins such as polyurethane resin, polyethersulfone, polycarbonate, polysulfone, polyether, polyetherketone, acrylonitrile, methacrylonitrile, cycloolefin polymer, cycloolefin copolymer, glass such as soda glass, potassium glass, lead glass And transparent inorganic materials such as ceramics such as lead lanthanum zirconate titanate (PLZT), quartz, and fluorite.

  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 said fine uneven | corrugated layer, and, thereby improving abrasion resistance (scratch resistance) on a transparent base material. This primer layer preferably has adhesiveness to the transparent substrate and the fine uneven layer adjacent to the transparent substrate via the primer layer and transmits visible light.
As a material for the primer layer, for example, a material selected from a fluorine-based coating agent, a silane coupling agent, and the like can be used as appropriate. Examples of commercially available fluorine-based coating agents include Fluorosurf FG-5010Z130 manufactured by Fluoro Technology, and examples of commercially available silane coupling agents include Durasurf Primer DS-PC-3B manufactured by Harves. Is 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.

  Moreover, in the antireflection article according to the present invention, a peelable protective film may be temporarily adhered to the surface of the fine unevenness side of the fine unevenness layer. Thereby, in a state where the protective film is temporarily bonded to the surface of the fine unevenness side of the fine unevenness layer, the antireflection article according to the present invention is stored, transported, bought and sold, post-processed or constructed, and the protective film is applied in a timely manner. Since it can be made into the form which peels and removes, the damage of the surface by the side of the fine grooving | roughness of the fine grooving | roughness layer during storage, conveyance, etc., and contamination can be prevented.

  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 the fine uneven | corrugated layer which has fine uneven | corrugated shape.
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 anodization and etching.

In FIG. 4, 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. 4, 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 material, for example, when making a sheet-shaped antireflection article by a shaping process using a flat plate, a master for forming a fine uneven layer with a specific curved surface, etc. The layer forming original plate can be appropriately changed according to the shape of the transparent substrate according to the shape of the antireflection article.
Further, in the antireflection article according to the present invention, the transparent substrate used in the production may be peeled off as necessary to provide only a fine uneven layer, or a transparent substrate as a resin composition for the fine uneven layer. By using the same material as that described above, the fine uneven layer and the transparent substrate may be integrated.

[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. 5, 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.

  The image display device of the present invention can easily wipe off the dirt adhered to the surface by wiping work while suppressing white turbidity in the antireflection article according to the present invention provided on at least one side of the display panel. , Have excellent antifouling properties and 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.

(Preparation of master A for forming fine uneven layer)
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 0.04 M oxalic acid aqueous solution. Anodization was performed for 120 seconds under conditions of a voltage of 75 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 a second etching treatment, a pore size treatment was performed with a 1.0 M phosphoric acid aqueous solution for 180 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 A for forming a fine uneven layer. In addition, the fine uneven | corrugated shape formed in the aluminum layer was a shape in which the average space | interval was 195 nm and many fine holes in which a hole diameter becomes small gradually are formed densely in the depth direction.

(Preparation of fine uneven layer forming master B)
A fine uneven layer forming original plate B was obtained in the same manner as described above except that in forming the fine uneven layer forming original plate A, the formation voltage was 52 V and the second etching treatment was performed for 130 seconds. The fine concavo-convex shape formed in the aluminum layer was a shape in which an average interval was 150 nm and a large number of fine holes with a gradually decreasing hole diameter were formed in the depth direction.

(Preparation of fine uneven layer forming master C)
In the production of the fine uneven layer forming master A, a fine uneven layer forming original plate C was obtained in the same manner as described above except that the formation voltage was 60 V and the second etching treatment was 120 seconds. The fine concavo-convex shape formed in the aluminum layer was a shape in which an average interval was 180 nm and a large number of micropores gradually decreasing in the depth direction were densely formed.

(Preparation of resin composition A for forming fine uneven layer)
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-trimethoxybenzoyl) ) 1 part by mass of hosifin oxide (lucillin TPO) was 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 dilution solvents.

(Preparation of resin composition B for forming fine uneven layer)
Pentaerythritol triacrylate 15 parts by mass, polyethylene glycol diacrylate 70 parts by mass, 2,4,4-trimethylhexamethylene diisocyanate 15 parts by mass, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (Lucillin TPO) 1 part by mass Parts 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 dilution solvents.

(Preparation of resin composition C for forming fine uneven layer)
15 parts by mass of pentaerythritol triacrylate, 35 parts by mass of polyethylene glycol diacrylate, 50 parts by mass of 1,4-butanediol diacrylate, 1 part by mass of diphenyl (2,4,6-trimethoxybenzoyl) fosifine oxide (lucillin TPO) Were mixed using methyl ethyl ketone and methyl isobutyl ketone as diluent solvents, to prepare a resin composition C for forming a fine uneven layer having a solid content of 45% by mass.

(Preparation of resin composition D for forming fine uneven layer)
30 parts by mass of pentaerythritol triacrylate, 20 parts by mass of polyethylene glycol diacrylate, 50 parts by mass of 1,4-butanediol diacrylate, 1 part by mass of diphenyl (2,4,6-trimethoxybenzoyl) fosifine oxide (lucillin TPO) Were mixed using methyl ethyl ketone and methyl isobutyl ketone as diluent solvents, to prepare a resin composition D for forming a fine uneven layer having a solid content of 45% by mass.

Example 1
As the resin composition for forming a fine concavo-convex layer, the resin composition A for forming a fine concavo-convex layer is coated with the fine concavo-convex surface of the original substrate A for forming a fine concavo-convex layer obtained above, and the thickness of the fine concavo-convex layer after curing Is applied and filled so that the thickness becomes 20 μm, and a 80 μm-thick triacetyl cellulose film (TAC) (manufactured by Fuji Film Co., Ltd.) is bonded obliquely thereon as a transparent substrate, and then the bonded body is bonded. Was pressed with a rubber roller under 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 of Example 1. The resulting fine projection group provided in the fine uneven layer of the antireflective article has an average adjacent projections spacing _{d AVG} is 195 nm (standard deviation sigma _d 38 nm), the mean height _{H AVG} was 370 nm.

(Example 2)
In Example 1, an antireflection article of Example 2 was obtained in the same manner as in Example 1 except that the fine uneven layer forming original plate B was used instead of the fine uneven layer forming original plate A. The resulting fine projection group provided in the fine uneven layer of the antireflective article has an average adjacent projections spacing _{d AVG} is 150 nm (standard deviation sigma _d 34 nm), the mean height _{H AVG} was 255 nm.

(Example 3)
In Example 1, an antireflection article of Example 3 was obtained in the same manner as in Example 1 except that the fine uneven layer forming original plate C was used instead of the fine uneven layer forming original plate A. The resulting fine projection group provided in the fine uneven layer of the antireflective article has an average adjacent projections spacing _{d AVG} is 180 nm (standard deviation sigma _d 38 nm), the mean height _{H AVG} was 255 nm.

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

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

(Comparative Example 3)
In Example 1, an antireflection article of Comparative Example 3 was obtained in the same manner as in Example 1 except that the resin composition D for forming a fine uneven layer was used instead of the resin composition A for forming a fine uneven layer. .

(Comparative Example 4)
In Example 2, an antireflection article of Comparative Example 4 was obtained in the same manner as in Example 2 except that the resin composition B for forming a fine uneven layer was used instead of the resin composition A for forming a fine uneven layer. .

<Measurement of storage elastic modulus (E ')>
About the hardened | cured material of resin composition AD for fine uneven | corrugated layer formation used in each Example and comparative example, the storage elastic modulus (E ') was measured with the following method.
The resin composition for forming a fine concavo-convex 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 concavo-convex shape, a thickness of 1 mm, a width of 5 mm, and a length A single test membrane having a thickness of 30 mm was 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 rate E ′ was determined. As a measuring device, Rheogel E400 made by UBM was used. The measurement results are shown in Table 1.

(Evaluation)
<Measurement of horizontal force>
A Barkovic indenter (tip ridge angle 105 °) was pushed to the depth shown in Table 1 into the surface on the fine uneven surface side (fine uneven surface) of the fine uneven layer of the anti-reflective article obtained in each Example and Comparative Example, and the temperature was 25 Measure the stress (horizontal force) when moved in the horizontal direction at a speed of 1 μm / 15 seconds at ℃, and calculate the average value of the horizontal force measured between 25 and 40 seconds after the start of indenter movement did. For measurement of the horizontal force, a nanoindenter (TI 950 TriboIndenter manufactured by HYSITRON) was used. Similarly, the horizontal force was measured three times in total, and the average value was calculated for each. The average value of the average values calculated from each measurement was further calculated to obtain the average horizontal force of the antireflection article. Table 1 shows the average of the calculated horizontal forces.

<Measurement of contact angle>
In each anti-reflective article obtained in each of the examples and comparative examples, a 1.0 μL drop of water was dropped on the anti-reflective article having a fine uneven surface on the top and attached to a black acrylic plate with an adhesive layer. The contact angle of water after 1 second of dropping was measured. As a measuring device, a contact angle meter DM 500 manufactured by Kyowa Interface Science Co., Ltd. was used. The measurement results are shown in Table 1.

<Wipeability evaluation>
Each antireflective article obtained in each Example and Comparative Example was attached to a black acrylic plate with an adhesive layer with the fine uneven surface on top, and an ultraviolet-visible spectrophotometer (trade name “V- 7100 "), the 5 ° regular reflectance to the surface of the antireflective article was measured with a double field of view (D65 light source) in accordance with JIS Z8701-1999.
Next, a finger was pressed against the fine uneven surface of the antireflection article to attach a fingerprint.
Thereafter, the fingerprint was wiped dry with a wiping cloth (Xavina Minimax, manufactured by Fuji Chemical). Dry wiping was performed 10 times with a force of about 3 kg / cm ² . About each anti-reflective article after dry-wiping, 5 degree regular reflectance was measured like the above. The difference (ΔY) between the value of 5 ° regular reflectance before fingerprint attachment measured above and the value of 5 ° regular reflectance after dry wiping was calculated.
Moreover, the fingerprint was wiped with water with the same force and frequency as in the case of the dry wiping. When wiping with water, a wiping cloth (Xavina Minimax, manufactured by Fuji Chemical Co., Ltd.) was sprayed with a moth eye panel cleaner (manufactured by Sharp) and sufficiently wetted. For each antireflective article after wiping, measure the 5 ° regular reflectance and calculate the difference (ΔY) between the 5 ° regular reflectance value before fingerprint attachment and the 5 ° regular reflectance value after water wiping. did.
Table 1 shows the respective values of ΔY.

<Evaluation of clouding (measurement of haze)>
The fine uneven surface of each antireflective article obtained in each Example and Comparative Example was wiped with water in the same manner as the above-described wiping evaluation, and each antireflective article after wiping was angled at 30 degrees with respect to the fine uneven surface. And visually determined whether it was clouded.
The case where the clouded state could not be observed was evaluated as A, and the case where it was observed was evaluated as B. The evaluation results are shown in Table 1.

(Summary of results)
The antireflective articles of Examples 1 to 3 are antireflective articles according to the present invention in which the contact angle of water on the fine uneven surface is 15 degrees or more and the average of the specific horizontal force is 8.0 μN or less. . Therefore, ΔY with respect to the antireflective article before adhesion of the fingerprint was small and excellent wiping property of dirt was obtained regardless of whether dry wiping or water wiping was performed. Moreover, the cloudiness before and after wiping was suppressed.
On the other hand, in the antireflection articles of Comparative Examples 1 and 4, since the water contact angle of the fine uneven surface was less than 15 degrees, white turbidity occurred after wiping with water, and the antireflection effect was visually impaired. It is presumed that the adjacent microprotrusions were adhered during wiping. In addition, the antireflection articles of Comparative Examples 1 and 4 could not measure the 5 ° regular reflectance after wiping with water due to cloudiness.
In the antireflection articles of Comparative Examples 2 and 3, the contact angle of water on the fine uneven surface was less than 15 degrees, and the average of the horizontal force was larger than 8.0 μN. Of ΔY was large, and the wipeability of dirt was poor.

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Fine uneven | corrugated layer 2a Fine uneven | corrugated surface 2 'Receptive layer 3 Minute protrusion 4 Display panel 5 Indenter 10 Antireflection article 11 Die 12 Roll die 13 Press roller 14 Peeling roller 20 Image display apparatus

Claims (2)

An antireflective article comprising a fine concavo-convex layer having a fine concavo-convex shape on the surface, which is formed of a cured product of a resin composition and has a microprojection group in which a plurality of microprotrusions are closely arranged,
When the shortest wavelength of the wavelength band of light for preventing reflection is Λ _min and the maximum value of the distance d between adjacent protrusions is d _max ,
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 contact angle of water on the surface of the fine concavo-convex shape side of the fine concavo-convex layer is 15 degrees or more,
The surface of the fine irregularities side of the fine uneven layer, the indenter is pushed by the average projection height H 55% to 75% of the indentation depth of _AVG of the microprojections, a temperature of 25 ° C., of 1 [mu] m / 15 sec An antireflective article characterized in that the average of horizontal force measured within 25 to 40 seconds after moving the indenter when moved in the horizontal direction at a speed is 8.0 μN or less.   An image display device comprising the antireflection article according to claim 1 on at least one surface side of the display panel.