JP6826803B2 - A photocurable resin composition, a cured film and antiglare film formed from the composition, an image display device, and a method for producing the cured film and antiglare film. - Google Patents

Description

The present invention relates to a photocurable resin composition, a cured film and antiglare film formed from the composition, an image display device, and a method for producing the cured film and antiglare film.

In image display devices (hereinafter, also simply referred to as displays) such as tablet terminals and televisions, the visibility of the screen is lowered due to the reflection of sunlight, fluorescent lamps, and the like on the screen. Therefore, an antiglare film is provided on the surface of the display in order to suppress reflection.

Generally, the antiglare film is formed by laminating a transparent base material and a cured film having antiglare properties (hereinafter, also simply referred to as an antiglare layer). The antiglare layer is formed by, for example, applying and curing a photocurable resin composition containing fine particles on a transparent base material, and has fine irregularities on the surface due to the fine particles. According to the antiglare film, the antiglare layer exhibits antiglare by scattering or diffusing light due to unevenness, so that reflection can be suppressed.

By the way, in recent years, the resolution of a display has been improved, and the displayed image has become higher definition. Along with this improvement in resolution, the antiglare film has a problem that when it is attached to a high resolution display, the surface of the antiglare layer has uneven brightness and the visibility of the screen is lowered. When the display is turned on, when the transmitted light from the back reaches the screen, fine unevenness of brightness (brightness) appears on the screen surface, and when the observer changes the viewing angle, the uneven brightness becomes uneven. This is a phenomenon in which the position of the light appears to change, especially when the entire white display or the entire green display is displayed. It is considered that this luminance unevenness is caused by the transmitted light interfering with the unevenness of the antiglare layer. As described above, in the antiglare film, antiglare property can be obtained by the unevenness of the antiglare layer, but since the unevenness causes uneven brightness, both excellent antiglare property and suppression of uneven brightness are achieved. That has become difficult.

As a method for solving this problem, a method of adjusting the difference between the refractive index of the resin constituting the antiglare layer of the antiglare film and the refractive index of the fine particles contained in the antiglare layer within a predetermined range is disclosed. (See, for example, Patent Documents 1 to 3).

Japanese Unexamined Patent Publication No. 11-326608 Japanese Unexamined Patent Publication No. 2008-262190 JP-A-2009-175375

However, the methods of Patent Documents 1 to 3 have a limit in suppressing brightness unevenness while maintaining excellent antiglare properties, and there is room for improvement.

The present invention has been made in view of the above problems, and is a photocurable resin composition capable of forming a cured film having excellent antiglare properties and less uneven brightness, a cured film and an antiglare film, an image display device, and the like. Another object of the present invention is to provide a method for producing a cured film and an antiglare film.

According to the first aspect of the present invention
A photocurable resin composition containing a photopolymerizable component (A), fine particles (B) and a photopolymerization initiator (C).
The photopolymerizable component (A) contains a photopolymerizable (meth) acrylic resin (a1) having a weight average molecular weight of 10,000 or more.
The fine particles (B) contain organic fine particles and / or inorganic fine particles having an average particle diameter of 1.0 μm or more and 2.8 μm or less.
Provided is a photocurable resin composition having a viscosity at 23 ° C. of 1 mPa · s or more and 1000 mPa · s or less.

According to the second aspect of the present invention
The photocurable resin composition of the first aspect is provided as the fine particles (B), which comprises silicon fine particles containing alumina fine particles.

According to the third aspect of the present invention
Provided is the photocurable resin composition of the first aspect or the second aspect, which contains the fine particles (B) in a range of 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of solid content. To.

According to the fourth aspect of the present invention
The first to first steps, wherein the photopolymerizable component (A) contains a (meth) acrylate-based monomer other than the photopolymerizable (meth) acrylic resin (a1) and / or a (meth) acrylate-based resin (a2). A photocurable resin composition according to any of the three aspects is provided.

According to the fifth aspect of the present invention
Provided is a cured film formed from the photocurable resin composition according to any one of the first to fourth aspects and having irregularities on the surface due to the fine particles (B).

According to the sixth aspect of the present invention
A fifth aspect of the cured coating having a surface roughness Ra of 0.01 μm or more and 0.17 μm or less is provided.

According to the seventh aspect of the present invention
Provided is a cured film according to a fifth or sixth aspect, wherein the average spacing Sm of the unevenness is 30 μm or more and 300 μm or less.

According to the eighth aspect of the present invention.
Provided is a cured coating according to any of the fifth to seventh aspects, wherein the 60 ° mirror surface gloss measured according to JIS K5600-4-7 is 120% or less.

According to the ninth aspect of the present invention.
An antiglare film comprising a transparent substrate and a cured coating according to any of the fifth to eighth aspects is provided.

According to the tenth aspect of the present invention.
A ninth aspect of the antiglare film is provided, wherein the turbidity measured according to JIS K7136 is 40% or less.

According to the eleventh aspect of the present invention
According to JIS K7374, the total value of image sharpness measured using optical combs with slit widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm is 350% or more. , A ninth aspect or a tenth aspect of the antiglare film is provided.

According to the twelfth aspect of the present invention
An image display device comprising the antiglare film of any of the ninth to eleventh aspects is provided.

According to the thirteenth aspect of the present invention.
Provided is a method for producing a cured film, which comprises a curing step of curing the photocurable resin composition according to any one of the first to fourth aspects by light irradiation.

According to the fourteenth aspect of the present invention.
A coating step of applying the photocurable resin composition according to any one of the first to fourth aspects to at least one main surface of the transparent substrate, and
Provided is a method for producing an antiglare film, which comprises a curing step of curing the photocurable resin composition by light irradiation to form a cured film after the coating step.

According to the present invention, a photocurable resin composition, a cured film and a film, and an image display device capable of forming an antiglare film having excellent antiglare properties and less uneven brightness can be obtained.

It is the schematic which shows a part of the cross section of the antiglare film which concerns on one Embodiment of this invention. It is the schematic which shows a part of the cross section of the conventional antiglare film.

As a result of studies by the present inventor in order to solve the above problems, it has been found that the causes of brightness unevenness in the conventional antiglare film are mainly the following two points.

One is that the unevenness of the antiglare layer is not densely formed in the plane. As shown in FIG. 2, in the antiglare layer 110, the convex portion 111 is formed on the surface by the presence of the fine particles (B) at a predetermined position in the thickness direction, but conventionally, the fine particles (B) are formed. There may be a portion 112 in the antiglare layer 110 that is settled and the convex portion is not partially formed. Therefore, the convex portions 111 are sparsely distributed in the plane of the antiglare layer 110, and the average interval Sm of the unevenness in the antiglare layer 110 is large.
The other is that the surface roughness due to unevenness is large. As shown in FIG. 2, in the antiglare layer 110, the surface roughness Ra is determined by the height of the convex portion 111 on the surface, but conventionally, coarse secondary particles formed by agglomeration of fine particles (B). This may result in a portion 113 in which the height of the convex portion is excessively large. As a result, the surface roughness Ra of the antiglare layer 110 is large.

As described above, when the average interval Sm of the unevenness and the surface roughness Ra of the antiglare layer 110 are increased, the transmitted light from the display is likely to interfere with the unevenness, and the brightness unevenness is likely to occur. From this, in order to reduce the brightness unevenness while maintaining the excellent antiglare property in the antiglare layer 110, it is preferable to configure the antiglare layer 110 so that the average interval Sm of the unevenness and the surface roughness Ra due to the unevenness are reduced. I understand.

Therefore, the present inventor has studied a method for suppressing sedimentation and aggregation of fine particles in a photocurable resin composition forming an antiglare layer in order to reduce the average spacing Sm of irregularities and the surface roughness Ra due to irregularities. went. Specifically, a method for suppressing sedimentation and aggregation of fine particles having an average particle diameter of 1.0 to 2.8 μm so as to be able to form desired irregularities and obtain a predetermined antiglare property was investigated.

First, the present inventor set a high viscosity of the photocurable resin composition and conducted a study. This is because, in general, when the viscosity is high, the fine particles dispersed in the photocurable resin composition are less likely to settle or aggregate. As a result of the examination, when the viscosity at 23 ° C. is in the range of 1 mPa · s or more and 1000 mPa · s or less, sedimentation and aggregation of fine particles can be suppressed, but photopolymerizable (meth) acrylic contained in the photocurable resin composition. It was found that if the molecular weight of the resin is low, sedimentation and aggregation cannot be sufficiently suppressed. That is, it was found that the adjustment of the viscosity alone is not sufficient to suppress the sedimentation and aggregation of the fine particles, and it is necessary to increase the molecular weight of the photopolymerizable (meth) acrylic resin.

Further studies on the molecular weight of the photopolymerizable (meth) acrylic resin revealed that if the weight average molecular weight is less than 10,000, precipitation and aggregation of fine particles cannot be sufficiently suppressed even if the viscosity is within the above range. It was found that when the weight average molecular weight is 10,000 or more, it can be suppressed well.

The present inventor speculates that this factor is as follows. In general, it is known that the lower the molecular weight, the shorter the molecular chain of the resin component, and the higher the molecular weight, the longer the molecular chain. According to the resin component having a high molecular weight and a long molecular chain, the size is larger than that of the resin component having a low molecular weight and a short molecular chain, so that it is easy to capture fine particles having a predetermined average particle size. Therefore, in the photocurable resin composition containing a high molecular weight resin component, the fine particles are trapped and the sedimentation is suppressed, so that the fine particles tend to float. Further, since the fine particles are captured and the aggregation of the fine particles is suppressed, the fine particles can be finely dispersed. Therefore, in the antiglare layer formed from the antiglare layer, sedimentation and aggregation of fine particles are suppressed, and the average spacing Sm of the unevenness and the surface roughness Ra due to the unevenness are reduced. That is, according to the above configuration, it is possible to form a cured film having excellent antiglare properties and less uneven brightness.

The present invention has been made based on the above findings.

Hereinafter, one embodiment of the present invention will be described in the following order.
1. 1. Photocurable resin composition 1-1. Photopolymerizable component (A)
1-2. Fine particles (B)
1-3. Photopolymerization initiator (C)
1-4. Viscosity 1-5. Other additives 1-6. Preparation method 2. Anti-glare film 3. Manufacturing method of anti-glare film 4. Effect of this embodiment

<1. Photocurable resin composition>
The photocurable resin composition according to the present embodiment is obtained by mixing a photopolymerizable component (A), fine particles (B), and a photopolymerization initiator (C), and has a viscosity at 23 ° C. of 1 mPa · s or more. It is 1000 mPa · s or less.

<1-1. Photopolymerizable component (A)>
The photopolymerizable component (A) contains a photopolymerizable (meth) acrylic resin (a1) having a weight average molecular weight of 10,000 or more (hereinafter, also simply referred to as “(meth) acrylic resin (a1)”). I'm out. In addition, in this specification, (meth) acrylic means at least one of acrylic and corresponding methacrylic.

The (meth) acrylic resin (a1) is a resin component having a polymer of a (meth) acrylic monomer in the main skeleton and a photopolymerizable functional group in the side chain. Examples of the photopolymerizable functional group include (meth) acryloyl group, vinyl group, allyl group and the like. Among them, the (meth) acryloyl group is preferable because of its high reactivity and high curing rate by light irradiation.

The weight average molecular weight of the (meth) acrylic resin (a1) is 10,000 or more, preferably 15,000 or more. As described above, when the weight average molecular weight is less than 10,000, the precipitation and aggregation of the fine particles (B) in the photocurable resin composition cannot be sufficiently suppressed, so that the average spacing Sm of the unevenness in the antiglare layer and the unevenness are used. The surface roughness Ra becomes large, and uneven brightness is likely to occur. In the cured film, the weight average molecular weight may be large from the viewpoint of preventing the occurrence of defects such as agglomerates and repellents and improving the appearance while reducing the average spacing Sm of the unevenness and the surface roughness Ra due to the unevenness. It is preferably 15,000 or more. The upper limit of the weight average molecular weight is not particularly limited, but is preferably 200,000 or less, more preferably 100,000 or less, and further preferably 60,000 or less. By setting such a weight average molecular weight, it is possible to obtain a desired high hardness in the cured film without impairing flexibility and flexibility. In this embodiment, the weight average molecular weight is calculated from the measurement result of gel permeation chromatography (GPC) using polystyrene as a standard.

The photopolymerizable component (A) preferably contains a (meth) acrylate-based monomer and / or a (meth) acrylate-based resin (a2) as a component other than the (meth) acrylic resin (a1). By containing such a (meth) acrylate-based monomer and / or (meth) acrylate-based resin (a2), the hardness and scratch resistance of the cured film can be improved.

As the (meth) acrylate-based monomer, for example, one having two or more polymerizable functional groups in the monomer can be used. Specifically, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di ( Bifunctional monomers such as meta) acrylate and tetraethylene glycol di (meth) acrylate: trimethylpropantri (meth) acrylate, tris (2- (meth) acryloyloxyethyl) isocyanurate, tris (2- (meth) acryloyloxy) Many such as propyl) isocyanurate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Examples include functional monomers. Among these, a polyfunctional monomer having four or more polymerizable functional groups in the monomer is particularly preferable from the viewpoint of improving the hardness of the cured film. These (meth) acrylate-based monomers can be used alone or in combination of two or more.
Further, as the (meth) acrylate-based resin, for example, a photocurable (meth) acrylate-based monomer such as urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, and epoxy (meth) acrylate is polymerized. The resin obtained by the above can be mentioned. These (meth) acrylate-based resins may be used alone or in combination of two or more.

The blending amount of the (meth) acrylate-based monomer and / or the (meth) acrylate-based resin (a2) is based on 100 parts by mass of the solid content of the photocurable resin composition from the viewpoint of not excessively improving the hardness of the cured film. It is preferably 0 parts by mass or more and 40 parts by mass or less, and more preferably 0 parts by mass or more and 20 parts by mass or less. In the present embodiment, the solid content is a photocurable resin composition obtained by removing volatile components such as an organic solvent, and indicates a component that remains as a cured film when cured.

<1-2. Fine particles (B)>
The fine particles (B) form irregularities on the surface of the cured film (antiglare layer) when the photocurable resin composition is cured. As the fine particles (B), those having an average particle diameter of 1.0 μm or more and 2.8 μm or less can be used. When the average particle size of the fine particles (B) is less than 1.0 μm, the height of the convex portion in the antiglare layer is small when the photocurable resin composition is cured, and the surface roughness Ra thereof is excessive. It becomes smaller. Therefore, the reflection cannot be sufficiently suppressed due to the unevenness, and high anti-glare property cannot be obtained. On the other hand, when the average particle size exceeds 2.8 μm, the height of the convex portion of the antiglare layer is large, and the surface roughness Ra becomes excessively large. Therefore, the brightness unevenness occurs in the antiglare layer and the visibility is lowered. In this embodiment, the average particle size indicates the median diameter (D50).

As the fine particles (B), conventionally known fine particles can be used. For example, as the organic fine particles, acrylic fine particles, polystyrene fine particles, polyethylene wax fine particles, polypropylene wax fine particles, PTFE fine particles, urethane fine particles, silicon fine particles and the like can be used. Further, for example, as the inorganic fine particles, metal oxide fine particles such as silicon dioxide fine particles, aluminum oxide fine particles, zirconium oxide fine particles, zinc oxide fine particles, and titanium oxide fine particles can be used. One of these may be used alone, or two or more thereof may be used in combination. As the fine particles (B), it is preferable to use silicon fine particles, which are organic fine particles, from the viewpoint of further suppressing uneven brightness. From the viewpoint of suppressing uneven brightness and suppressing glare to improve antiglare, silicon fine particles containing alumina fine particles are more preferable. The silicon fine particles containing the alumina fine particles are superior in light diffusivity as compared with the silicon fine particles, and can further improve the antiglare property.

The blending amount of the fine particles (B) can be appropriately changed according to various properties such as antiglare, scratch resistance and transparency (turbidity) required for the cured film. When the photocurable resin composition is applied to an antiglare film to be attached to the screen of an image display device, various characteristics are required in a well-balanced manner. Therefore, the blending amount of the fine particles (B) is the photocurable resin composition. It is preferably 0.1 part by mass or more and 20 parts by mass or less, and more preferably 4 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the solid content. If the blending amount of the fine particles (B) is less than the above range, various characteristics may not be obtained in a well-balanced manner, and if it is more than the above range, the turbidity of the cured film may increase and the transparency may be impaired. is there.

<1-3. Photopolymerization initiator (C)>
The photopolymerization initiator (C) generates radicals or cations by light irradiation to cure the photopolymerizable component (A). The photopolymerization initiator (C) may be any as long as it can cure the photopolymerizable component (A). For example, a benzoin-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, a thioxanthone-based photopolymerization initiator, and the like can be used.
Examples of the benzoin-based photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.
Examples of the acetophenone-based photopolymerization initiator include benzyldimethylketal (also known as 2,2-dimethoxy-2-phenylacetophenone), diethoxyacetophenone, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, and 4-t-. Butyl-trichloroacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecyl) Phenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4- (Methylthio) phenyl] -2-morpholinopropane-1-one and the like can be mentioned.
Examples of the benzophenone-based photopolymerization initiator include benzophenone, benzoyl benzoic acid, methyl benzoyl benzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylicized benzophenone, 4-benzoyl-4'-methyldiphenyl sulfate, and 3,3'-dimethyl-. Examples thereof include 4-methoxybenzophenone.
Examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropyl. Examples thereof include thioxanthone.
One of these photopolymerization initiators may be used alone, or two or more thereof may be used in combination.

The blending amount of the photopolymerization initiator (C) is preferably 0.1 part by mass or more and 10 parts by mass or less, and more preferably 3 parts by mass or more and 6 parts by mass with respect to 100 parts by mass of the solid content of the photocurable resin composition. It is less than a part. If the blending amount is less than the above range, the rate (curing rate) at which the photocurable resin composition is cured may be slow, and if it is more than the above range, the curing rate may be excessively high. ..

<1-4. Viscosity>
The viscosity of the photocurable resin composition according to the present embodiment is 1 mPa · s or more and 1000 mPa · s or less at 23 ° C. It is preferably 1 to 500 mPa · s, more preferably 3 to 60 mPa · s, and even more preferably 3 to 40 mPa · s. If the viscosity is less than 1 mPa · s, the viscosity becomes excessively low, so that the fine particles (B) settle or aggregate in the photocurable resin composition. On the other hand, if the viscosity exceeds 1000 mPa · s, the leveling property of the photocurable resin composition becomes low, so that it becomes difficult to apply and it becomes impossible to form a cured film having a uniform film thickness.

<1-5. Other additives>
The photocurable resin composition according to the present embodiment may contain other additives other than the above-mentioned components, if necessary. As another additive, an organic solvent may be contained from the viewpoint of adjusting the viscosity within a predetermined range. As the organic solvent, conventionally known ones can be used. For example, aromatic hydrocarbons (eg xylene, toluene, etc.), ketones (eg, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, etc.), esters (eg, ethyl acetate, butyl acetate, isobutyl acetate, etc.), alcohols (eg, ethyl acetate, butyl acetate, isobutyl acetate, etc.) Examples include various organic solvents such as isopropyl alcohol, butanol, etc., and glycol ethers (eg, propylene glycol monomethyl ether, etc.). These organic solvents can be used alone or in combination of two or more.

In addition, a leveling agent may be contained as another additive. According to the leveling agent, it is possible to improve the repelling of the photocurable resin composition, improve the wettability to the surface to be coated, and form a cured film having a uniform film thickness. Examples of the leveling agent include various leveling agents such as fluorine-based, acrylic-based, and silicon-based. Among them, a fluorine-based leveling agent is more preferable because it can not only improve the leveling property but also impart antifouling functions such as water repellency and oil repellency. The blending amount of these leveling agents is preferably 0.1 part by mass or more and 1.5 parts by mass or less, and 0.5 parts by mass or more and 1.0 part by mass or less with respect to 100 parts by mass of the solid content of the photocurable composition. Is more preferable.

In addition, a defoaming agent may be contained as another additive. According to the defoaming agent, it is possible to suppress the generation of air bubbles in the photocurable resin composition and improve the appearance of the cured film. Examples of the defoaming agent include various defoaming agents such as acrylic type and silicon type. The blending amount of these antifoaming agents is preferably 0.0001 mass or more and 1.0 mass part or less with respect to 100 parts by mass of the solid content of the photocurable composition.

Further, as other additives, a polymerization inhibitor, a non-reactive diluent, a matting agent, a precipitation inhibitor, a dispersant, a heat stabilizer, an ultraviolet absorber and the like may be contained. These blending amounts can be appropriately changed as long as the effects of the present embodiment are not impaired.

<1-6. Preparation method>
The photocurable resin composition according to the present embodiment is prepared, for example, as follows.
First, the photopolymerizable component (A), the photopolymerization initiator (C), and other additives, if necessary, are dissolved in the organic solvent. Subsequently, the fine particles (B) are added to the obtained solution and stirred to obtain the photocurable resin composition of the present embodiment. At the time of preparation, it is advisable to appropriately change the blending amounts of the photopolymerizable component (A), the fine particles (B), the organic solvent and the like so that the viscosity of the photocurable resin composition is within a predetermined range.

<2. Anti-glare film>
Subsequently, the antiglare film 1 formed by using the above-mentioned photocurable resin composition will be described with reference to FIG. FIG. 1 is a schematic view showing a cross section of an antiglare film 1 according to an embodiment of the present invention.

As shown in FIG. 1, the antiglare film 1 according to the present embodiment includes a transparent base material 20 and a cured film (antiglare layer) 10.

As the transparent base material 20, a transparent plastic film made of a transparent material can be used. Examples of the transparent plastic film include triacetyl cellulose film, polyethylene terephthalate (PET) film, diacetyl cellulose film, acetate butyrate cellulose film, polyether sulfone film, polyacrylic resin film, polyurethane resin film, polyester film, and the like. Examples thereof include a polycarbonate film, a polysulfone film, a polyether film, a polymethylpentene film, a polyether ketone film, and a (meth) acrylic nitrile film. Among these, polyethylene terephthalate film is preferable in terms of balance of strength and optical characteristics.

The cured film (antiglare layer) 10 is provided on one main surface of the transparent base material 20. The cured film 10 is formed of a photocurable resin composition and has irregularities on the surface due to the fine particles (B). As described above, in the photocurable resin composition, sedimentation and aggregation of the fine particles (B) are suppressed. Therefore, when the photocurable resin composition is applied, the fine particles (B) float in the thickness direction without settling and are finely dispersed without agglomeration in the coating film. In the cured coating film 10 obtained by curing this coating film, the precipitation of the fine particles (B) is suppressed and the convex portions 11 due to the fine particles (B) are uniformly formed in the plane, so that the unevenness is densely distributed. It has become. Further, since the convex portion 11 is formed so that the aggregation of the fine particles (B) is suppressed and the height of the convex portion 11 does not become excessively large, the surface roughness due to the unevenness in the cured film 10 is reduced. ..

Specifically, in the cured film 10, the unevenness is densely formed, and the average interval Sm of the unevenness is preferably 30 μm or more and 300 μm or less, and more preferably 40 μm or more and 200 μm or less. The average interval Sm indicates the average of the distances between the convex portions 11, and the larger the average interval Sm, the smaller the density of the convex portions 11. When the average interval Sm exceeds 300 μm, the unevenness becomes sparse, so that uneven brightness is suppressed, but it is difficult to obtain excellent antiglare properties.

Further, in the cured film 10, the surface roughness Ra due to the unevenness is preferably 0.01 μm or more and 0.17 μm or less, and more preferably 0.05 μm or more and 0.15 μm or less. If the surface roughness Ra is less than 0.01 μm, excellent antiglare properties cannot be obtained, and if it exceeds 0.17 μm, uneven brightness may not be sufficiently suppressed.

The antiglare film 1 according to the present embodiment can be particularly preferably used on the outermost surface of a tablet terminal, but can also be applied to a display such as a television.

The cured film 10 may be formed not only on one side of the transparent base material 20 but also on both sides. Further, another layer (not shown) may be formed between the transparent base material 20 and the cured film 10. Examples of other layers include a polarizing layer, a light diffusion layer, a low reflection layer, an antifouling layer, an antistatic layer, an ultraviolet / near infrared (NIR) absorption layer, a neon cut layer, and an electromagnetic wave shield layer. .. Further, a coating layer (not shown) such as an antifouling layer may be formed on the surface of the cured coating film 10.

<3. Manufacturing method of anti-glare film>
Subsequently, the method for producing the antiglare film 1 described above will be described. The antiglare film 1 is manufactured, for example, by the following steps.

(Preparation process)
First, a PET film having a thickness of, for example, 100 μm is prepared as the transparent base material 20.

(Applying process)
Subsequently, the photocurable resin composition is applied onto one main surface of the transparent base material 20 to form a coating film. The thickness of the coating film (coating thickness of the photocurable resin composition) at this time varies depending on the characteristics required for the cured film (antiglare layer) 10, but for example, the thickness of the cured film 10 is at least 1 μm or more. It is preferably adjusted to be 2 μm or more. On the other hand, the upper limit of the thickness of the cured film is not particularly limited, but from the viewpoint of handleability of the antiglare film 1, the thickness of the coating film is adjusted so as to be, for example, 4 μm or less, preferably 3 μm or less. Good.

The coating method can be appropriately changed depending on the type and composition of the photocurable resin composition, the type of the transparent base material 20 to be coated, and the like. For example, a spray coating method, a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, an extrusion coating method and the like can be mentioned. Among these, the spray coating method is preferable from the viewpoint of workability and productivity.

(Light irradiation process)
Subsequently, the coating film is irradiated with active energy rays. Examples of active energy rays include electromagnetic waves such as X-rays and γ-rays, electron beams, proton beams, neutron rays, etc., in addition to rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, and infrared rays. Ultraviolet rays are preferable in terms of availability and price of the irradiation device. Examples of the method of curing with ultraviolet rays include a method of irradiating about 100 to 3000 mJ / cm ² using a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp or the like that emits light in the wavelength range of 200 to 500 nm.

The photocurable resin composition is cured by light irradiation for a predetermined time to form a cured film 10. As a result, the antiglare film 1 according to the present embodiment is obtained.

In this embodiment, a drying step of drying the photocurable resin composition may be provided between the coating step and the light irradiation step. Examples of the drying method include vacuum drying, heat drying, and a method of combining these drying methods.

<4. Effect of this embodiment>
According to this embodiment, one or more of the following effects are exhibited.

According to the photocurable resin composition of the present embodiment, the (meth) acrylic resin (a1) having a weight average molecular weight of 10,000 or more and the fine particles (B) having an average particle diameter of 1.0 μm or more and 2.8 μm or less. And, are configured so that the viscosity at 23 ° C. is 1 mPa · s or more and 1000 mPa · s or less. As a result, the sedimentation of the fine particles (B) in the photocurable resin composition can be suppressed, so that the convex portions 11 due to the fine particles (B) are densely formed in the cured coating film 10 formed from the fine particles (B), and the average spacing of the irregularities Sm. Can be small, for example, in the range of 30 to 300 μm. At the same time, since the aggregation of the fine particles (B) can be suppressed, the convex portion 11 due to the fine particles (B) can be formed so as not to become excessively large, so that the surface roughness Ra of the cured coating 10 can be reduced, for example, 0.01 to 0. It can be configured in the range of .17 μm. Therefore, according to the present embodiment, it is possible to form a cured film 10 having excellent antiglare properties and less uneven brightness, and an antiglare film 1 including the cured film 10.

Further, in the present embodiment, as the fine particles (B), silicon fine particles containing alumina fine particles may be used. Since the silicon fine particles containing the alumina fine particles are superior in light diffusivity as compared with the silicon fine particles and the like, the antiglare property of the cured film 10 can be further improved.

Further, in the present embodiment, the fine particles (B) may be contained in the range of 0.1 to 20 parts by mass with respect to 100 parts by mass of the solid content. As a result, the scratch resistance of the cured film 10 can be obtained, and the increase in turbidity due to the fine particles (B) can be suppressed to ensure transparency.

Further, in the present embodiment, the photopolymerizable component (A) may contain a (meth) acrylate-based monomer and / or a (meth) acrylate-based resin (a2) in addition to the (meth) acrylic resin (a1). .. As a result, the hardness of the cured film 10 can be improved, and the scratch resistance can be further improved.

Further, in the present embodiment, the cured coating film 10 is excellent in antiglare property, and preferably, the 60 ° mirror surface glossiness measured in accordance with JIS K5600-4-7, which is an index of antiglare property, is 120%. It becomes as follows.

Further, in the present embodiment, the antiglare film 1 provided with the cured film 10 is excellent in transparency, and the turbidity measured in accordance with JIS K7136, which is an index of transparency, is 40% or less.

Further, in the present embodiment, since the antiglare film 1 includes a cured film 10 having excellent antiglare properties and less uneven brightness, it is possible to suppress reflection of light on the screen and glare on the screen. .. That is, the antiglare film 1 is excellent in visibility. Specifically, the total value of image sharpness measured using optical combs having slit widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm according to JIS K7374 is It is 350% or more and has excellent visibility.

Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

<Example 1>
〔material〕
The raw materials used are as follows.

As a photopolymerizable component (A)
A photopolymerizable (meth) acrylic resin (a1) (Taisei Fine Chemicals) having an acrylic main skeleton, a (meth) acryloyl group as a photopolymerizable functional group in the side chain, and a weight average molecular weight (Mw) of 40,000. "Acrylo 8KX-078" manufactured by Co., Ltd., solid content 40%) was used.

As fine particles (B)
Alumina fine particle-encapsulating silicon fine particles (aluminum oxide fine particle-encapsulating polyorganosylsesquioxane fine particles: 100% solid content) having an average particle diameter of 1.9 μm were used. The average particle size was measured under the following conditions using a laser diffraction type particle size distribution measuring device (“SALD-2200” manufactured by Shimadzu Corporation).
Dispersion medium: Water dispersant: Sodium hexametaphosphate Rotation speed: 7
Ultrasonic dispersion time: 10 minutes

As a photopolymerization initiator (C)
1-Hydroxy-cyclohexyl-phenyl-ketone (BASF Corporation "Irgacure 184D", 100% solid content) and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (BASF Corporation "Irga""CureTPO", solid content 100%) and was used.

As other additives
Hydroquinone, a polymerization inhibitor (manufactured by Mitsui Chemicals, Inc., 100% solid content),
Silicone antifoaming agent ("BYK-066N" manufactured by BYK Co., Ltd., solid content 1%) and
Fluorine-based leveling agent ("Mega Fvck RS-75" manufactured by DIC Corporation, solid content 40%),
Methyl ethyl ketone, which is an organic solvent, was used.

[Preparation of photocurable resin composition]
As shown in Table 1 below, the photocurable resin composition of Example 1 was prepared by blending the above raw materials.
Specifically, 67.0 parts by mass of a photopolymerizable acrylic resin (a1) having a weight average molecular weight (Mw) of 40,000 as a photopolymerizable component (A) was added to 29.3 parts by mass of methyl ethyl ketone (A1). C) As a photopolymerization initiator, 0.6 parts by mass of Irgacure 184D, 0.6 parts by mass of Irgacure TPO, and as other additives, 0.02 parts by mass of hydroquinone and a silicon-based defoaming agent. 0.02 parts by mass and 0.7 parts by mass of the fluorine-based leveling agent were added and dissolved. Then, 1.8 parts by mass of alumina fine particle-encapsulating silicon fine particles having an average particle diameter of 1.9 μm was added to the solution and stirred. As a result, a photocurable resin composition in which the fine particles (B) were dispersed was obtained.

When the viscosity of the prepared photocurable resin composition was measured at 23 ° C. using a viscometer (“HAAKE Viscotester 6 plus” manufactured by Thermo Fisher Scientific Co., Ltd.), it was confirmed to be 16 mPa · s.

[Making anti-glare film]
Next, an antiglare film was prepared using the photocurable resin composition obtained above.
First, as a transparent base material, a PET film (“Cosmo Shine A4300” manufactured by Toyobo Co., Ltd., length 200 mm × width 150 mm × thickness 100 μm) was prepared. Subsequently, the photocurable resin composition prepared above was applied to one main surface of the PET film to form a coating film. At this time, the thickness of the coating film was adjusted and applied so that the film thickness (dry film thickness) of the obtained cured film was 2 to 3 μm. Subsequently, the coating film was irradiated with ultraviolet rays using a high-pressure mercury lamp (irradiation amount: 300 to 400 mJ / cm ² ). The coating film was cured by irradiation to form a cured film having a film thickness of 2.0 μm, and the antiglare film of this example was produced.

Regarding the obtained antiglare film, when the average interval Sm of the unevenness in the cured film and the surface roughness Ra due to the unevenness were measured, the average interval Sm was 49.6 μm and the surface roughness Ra was 0.11 μm. Was confirmed. The average interval Sm and the surface roughness Ra were measured using an ultra-compact surface roughness measuring machine E-35B (manufactured by Tokyo Seimitsu Co., Ltd.).

〔Evaluation methods〕
Next, the obtained antiglare film was evaluated as follows.

(Anti-glare)
The 60 ° mirror surface gloss was measured according to JIS K5600-4-7, and the antiglare property of the antiglare film was evaluated. In this example, when the 60 ° mirror surface glossiness was 120% or less, it was evaluated that the antiglare property was excellent.

(Brightness unevenness)
The degree of luminance unevenness was evaluated by visually judging the glare of the image projected on the antiglare film. Specifically, "iPad (registered trademark)" is used as an image display device, the display display is set to green by the application software "Free Light", and the antiglare film is cured with the coated surface facing the front side. The glare of the image when it was placed on the display and lightly pressed was visually judged. In this example, the degree of glare was classified into the following levels, and when the level was 3 or more, it was evaluated that the brightness unevenness was small.
5: No glare at all 4: Almost no glare 3: Some glare but acceptable 2: Lots of glare 1: Lots of glare

(Turbidity)
The turbidity (haze: HZ) of the antiglare film was measured and evaluated according to JIS K7136. In this example, when the turbidity was 40% or less, the visibility of the image was excellent, and when it was 20% or less, it was evaluated to be particularly excellent. The turbidity was measured using a haze meter (NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.).

(Total light transmittance)
The total light transmittance (TT) of the antiglare film was measured and evaluated according to JIS K7361. In this example, if the total light transmittance is 85% or more, it is evaluated that the transmittance is high. The total light transmittance was measured using a haze meter (NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.).

(Image sharpness)
The image sharpness is a numerical evaluation of how clear an image that can be observed through an antiglare film looks, and is measured in accordance with JIS K7374. In this embodiment, image sharpness measured using five types of optical combs (slit widths: 0.125 mm, 0.25 mm, 0.5 mm, 1 mm and 2 mm) having different slit widths in accordance with JIS K7374. It was evaluated by the total value of, and if the total value was 350% or more, it was evaluated that the image was clearly visible. The image sharpness was measured using ICM-1T manufactured by Suga Test Instruments Co., Ltd.

(hardness)
A pencil hardness test was performed under a load of 750 g in accordance with JIS K 5600, and the pencil hardness of the antiglare film was measured and evaluated. In this example, when the pencil hardness was H or more, it was evaluated that it had sufficient hardness and was excellent in scratch resistance.

(appearance)
The antiglare film is tilted 45 ° from the state where the cured film is facing upward, and the cured film is visually observed through the transparent substrate, and the presence or absence of fine particle agglomerates on the surface of the cured film, the presence or absence of cissing, and the surface The uniformity of was evaluated. In this example, those having no agglomerates or repellents and having a uniform surface were evaluated as having a good appearance.

<Example 2>
In Example 2, a photocurable resin composition was prepared in the same manner as in Example 1 except that a photopolymerizable (meth) acrylic resin (a1) having a weight average molecular weight of 10,000 was used. An antiglare film was produced.

<Example 3>
In Example 3, a photocurable resin composition was prepared in the same manner as in Example 1 except that a photopolymerizable (meth) acrylic resin (a1) having a weight average molecular weight of 20,000 was used. An antiglare film was produced.

<Example 4>
In Example 4, a photocurable resin composition was prepared in the same manner as in Example 1 except that a photopolymerizable (meth) acrylic resin (a1) having a weight average molecular weight of 80,000 was used. An antiglare film was produced.

< Reference example 1 >
In Reference Example 1 , a photocurable resin composition was prepared in the same manner as in Example 1 except that silicon fine particles having an average particle diameter of 2.0 μm were used as the fine particles (B) to prepare an antiglare film.

<Example 5 >
In Example 5 , the (meth) acrylate-based monomer (a2) was used together with the photopolymerizable (meth) acrylic resin (a1) as the photopolymerizable component (A), except that the blending amount was appropriately changed. A photocurable resin composition was prepared in the same manner as in 1. In this example, a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (solid content 100%) was used as the (meth) acrylate-based monomer (a2).

< Reference example 2 >
In Reference Example 2 , a photocurable resin composition was prepared in the same manner as in Example 5 except that acrylic fine particles having an average particle diameter of 1.2 μm were used as the fine particles (B) to prepare an antiglare film.

< Reference example 3 >
In Reference Example 3 , a photocurable resin composition was prepared in the same manner as in Example 5 except that acrylic fine particles having an average particle diameter of 2.3 μm were used as the fine particles (B) to prepare an antiglare film.

< Reference example 4 >
In Reference Example 4 , a photocurable resin composition was prepared in the same manner as in Example 5 except that hydrophobic silica fine particles having an average particle diameter of 2.1 μm were used as the fine particles (B) to prepare an antiglare film. ..

<Comparative example 1>
In Comparative Example 1, as shown in Table 2 below, a urethane acrylate resin (solid content) having a weight average molecular weight of 900 without using a photopolymerizable (meth) acrylic resin (a1) as the photopolymerizable component (A). 40%) was used to prepare a photocurable resin composition in the same manner as in Example 1 except that the blending amount was appropriately changed to prepare an antiglare film.

<Comparative example 2>
In Comparative Example 2, a photocurable resin composition was prepared in the same manner as in Example 5 except that alumina fine particle-encapsulating silicon fine particles having an average particle diameter of 3.0 μm were used as the fine particles (B), and an antiglare film was prepared. Was produced.

<Comparative example 3>
In Comparative Example 3, a photocurable resin composition was prepared in the same manner as in Example 5 except that acrylic fine particles having an average particle diameter of 3.0 μm were used as the fine particles (B) to prepare an antiglare film.

<Comparative example 4>
In Comparative Example 4, a photocurable resin composition was prepared in the same manner as in Example 5 except that acrylic fine particles having an average particle diameter of 0.7 μm were used as the fine particles (B) to prepare an antiglare film.

<Comparative example 5>
In Comparative Example 5, a photocurable resin composition was prepared in the same manner as in Example 5 except that acrylic fine particles having an average particle diameter of 0.8 μm were used as the fine particles (B) to prepare an antiglare film.

As shown in Table 1, in the antiglare films of Examples 1 to 5 and Reference Examples 1 to 4 , the average spacing Sm of the unevenness is 30 to 300 μm, and the surface average roughness Ra is 0.01 to 0. It was confirmed to be 17 μm. It was confirmed that Examples 1 to 5 and Reference Examples 1 to 4 had a 60 ° mirror surface gloss of 120% or less and were excellent in antiglare property. In addition, the level of glare was 3 or more, and the brightness unevenness was small. It was also confirmed that the turbidity, total light transmittance, image sharpness and hardness were also excellent.

When Examples 1, 3 to 5 and Reference Examples 1 to 4 are compared with Example 2, in Examples 1 , 3 to 5 and Reference Examples 1 to 4 , photopolymerizability having a weight average molecular weight of 15,000 or more is achieved . Since the acrylic resin (a1) was used, it was confirmed that the appearance of the cured film could be improved as compared with Example 2 using the photopolymerizable acrylic resin (a1) having a weight average molecular weight of 10,000.

When Example 1 and Reference Example 1 are compared, in Example 1 in which alumina fine particles-encapsulating silicon fine particles are used as the fine particles (B), the mirror glossiness is reduced by 60 ° as compared with Reference Example 1 in which silicon fine particles are used. It was confirmed that it was possible and was superior in anti-glare property. It is presumed that this is because the alumina fine particle-encapsulating silicon fine particles are superior in light diffusivity to the silicon fine particles.

When compared with Examples 1-4 and Reference Example 1 and Example 5 and Reference Examples 2-4, Example 5 and Reference Example 2-4, since using the acrylate monomer (a2), Examples 1 It was confirmed that the hardness of the cured film could be made higher than that of 4 and Reference Example 1 .

As shown in Table 2, in Comparative Example 1, it was confirmed that the average spacing Sm of the unevenness was as large as 354.3 μm, and the convex portions due to the fine particles (B) were not densely formed. As a result, it was confirmed that the 60 ° mirror surface glossiness was as high as 141% and the antiglare property was inferior. It is presumed that this is because the fine particles (B) settled in the antiglare layer because the urethane acrylate resin having a low weight average molecular weight was used.

In Comparative Examples 2 and 3, since the fine particles (B) having an average particle diameter larger than 2.8 μm were used, it was confirmed that the surface roughness Ra was larger than 0.17 μm. As a result, it was confirmed that the brightness unevenness increased and the image sharpness decreased.

In Comparative Examples 4 and 5, fine particles (B) having an average particle diameter smaller than 1.0 μm were used, and it was confirmed that the average interval Sm was larger than 300 μm. As a result, it was confirmed that although the brightness unevenness was small, the 60 ° mirror surface glossiness was higher than 120%, and sufficient antiglare property could not be obtained, probably because the unevenness was not formed precisely.

1 Anti-glare film 10 Cured film (anti-glare layer)
11 Convex part 20 Transparent base material

Claims (14)

A photocurable resin composition containing a photopolymerizable component (A), fine particles (B) and a photopolymerization initiator (C).
The photopolymerizable component (A) contains only a photopolymerizable (meth) acrylic resin (a1) having a weight average molecular weight of 10,000 or more.
The fine particles (B) are polyorganosylsesquioxane fine particles containing aluminum oxide fine particles having an average particle diameter of 1.0 μm or more and 2.8 μm or less.
A photocurable resin composition having a viscosity at 23 ° C. of 13 mPa · s or more and 1000 mPa · s or less. A photocurable resin composition containing a photopolymerizable component (A), fine particles (B) and a photopolymerization initiator (C).
The photopolymerizable component (A) is photopolymerizable other than the photopolymerizable (meth) acrylic resin (a1) having a weight average molecular weight of 10,000 or more and the photopolymerizable (meth) acrylic resin (a1). The photocurable resin composition comprises only the (meth) acrylate-based monomer and / or the (meth) acrylate-based resin (a2), and the (meth) acrylate-based monomer and / or the (meth) acrylate-based resin (a2). In an amount of 40 parts by mass or less with respect to 100 parts by mass of the solid content of
The fine particles (B) are polyorganosylsesquioxane fine particles containing aluminum oxide fine particles having an average particle diameter of 1.0 μm or more and 2.8 μm or less.
A photocurable resin composition having a viscosity at 23 ° C. of 13 mPa · s or more and 1000 mPa · s or less. The first or second claim, wherein the fine particles (B) are contained in a range of 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the solid content of the photocurable resin composition. Photocurable resin composition. The photocurable resin composition according to any one of claims 1 to 3, which is used for forming an antiglare film. A cured film formed from the photocurable resin composition according to any one of claims 1 to 4, characterized by having irregularities due to the fine particles (B) on the surface. The cured coating according to claim 5, wherein the surface roughness Ra is 0.01 μm or more and 0.17 μm or less. The cured coating according to claim 5 or 6, wherein the average spacing Sm of the unevenness is 30 μm or more and 300 μm or less. The cured coating according to any one of claims 5 to 7, wherein the 60 ° mirror surface gloss measured in accordance with JIS K5600-4-7 is 120% or less. An antiglare film comprising a transparent base material and the cured film according to any one of claims 5 to 8 provided on the transparent base material. The antiglare film according to claim 9, wherein the turbidity measured in accordance with JIS K7136 is 40% or less. According to JIS K7374, the total value of image sharpness measured using optical combs with slit widths of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm is 350% or more. The antiglare film according to claim 9 or 10. An image display device comprising the antiglare film according to any one of claims 9 to 11. A method for producing a cured film, which comprises a curing step of curing the photocurable resin composition according to any one of claims 1 to 4 by light irradiation. A coating step of applying the photocurable resin composition according to any one of claims 1 to 4 to at least one main surface of a transparent substrate.
A method for producing an antiglare film, which comprises, after the coating step, a curing step of curing the photocurable resin composition by light irradiation to form a cured film.