JP4582305B2 - Method for producing antireflection film - Google Patents

Description

  The present invention relates to a method for producing an antiglare antireflection film for a display having excellent in-plane uniformity and excellent antiglare properties, surface hardness, and contrast.

  Usually, the display surface is glass or plastic, but a hard coat treatment with a methacrylic resin is performed to prevent the screen from being damaged. Since the methacrylic resin exhibits high surface hardness, it exhibits good scratching properties, but also has a feature of high glossiness, which causes a new problem of glare on the display surface. In order to solve this problem, Patent Document 1 discloses an antiglare treatment in which a cohesive silica gel is blended with a polyester acrylate resin. Thus, by blending inorganic particles such as silica gel particles, high anti-glare properties can be obtained, but since the reflected light on the surface also scatters at the same time, it looks whitish and the image contrast is low. Lowering becomes a new problem.

  Therefore, by laminating an antireflection layer on the antiglare layer, it is possible to suppress the surface scattering effect and achieve both high contrast and antiglare properties. For example, by laminating a fluorine-based low refractive index layer having a refractive index of 1.38 to 1.49 on an antiglare hard coat layer containing particles of 0.3 to 10.0 μm, the contrast is reduced and the image is reflected Japanese Patent Application Laid-Open No. H10-228707 proposes to prevent the jamming.

  However, coating of a fluorine-based low refractive index material is very difficult due to the repelling caused by the surface energy inherent to fluorine. In addition, when forming a film on the uneven antiglare layer by the wet coating method, the thickness in the film varies due to the leveling of the coating liquid, and it is difficult to form an antireflection layer uniformly. Another problem is that the film becomes uneven.

Patent literature is described below.
JP 59-151109 A JP 2001-281411 A

  The present invention has been made to solve the above-described problems, and is excellent in antiglare property, surface hardness, and contrast, and has high in-plane uniformity and high reliability in antiglare antireflection for displays. It aims at providing the manufacturing method of a film.

In order to achieve the above object, that is, the invention according to claim 1 is an antireflection film in which a hard coat layer (B) and an antireflection layer (C) are sequentially laminated on at least a base material (A). A manufacturing method comprising:
The antireflection layer (C), on the hard coat layer (B), after deposited by flash evaporation method with a fluorine functional group in the molecule in vacuum (meth) acryloyl compound (D), an active energy ray Is formed by irradiating and curing the (meth) acryloyl compound (D).

The invention according to claim 2 is characterized in that the hard coat layer (B) includes a compound (E) having a (meth) acryloyl group in the molecule and fine particles (F) having a particle diameter of 1 μm to 10 μm, and (meth) acryloyl The method for producing an antireflection film according to claim 1, wherein a difference in refractive index between the compound (E) having a group in the molecule and the fine particles (F) is 0.01 or less.

  The invention according to claim 3 is the method for producing an antireflection film according to claim 1 or 2, wherein the fine particles (F) are organic resin fine particles (G).

  The invention according to claim 4 is the method for producing an antireflection film according to claim 1 or 2, wherein the fine particles (F) are inorganic fine particles (H).

  According to the present invention, by laminating a (meth) acryloyl compound having a low refractive index on a hard coat layer containing fine particles by flash vapor deposition, the antiglare property, surface hardness, and contrast are excellent, and the film thickness is uneven. A highly reliable antiglare antireflection film for display having high uniformity in the surface without any defects can be produced. In addition, the antireflection film obtained by the production method of the present invention can be used for various products, but can be particularly suitably used as a protective film for display products.

  Hereinafter, an exemplary embodiment of the present invention will be described in detail. The method for producing an antireflection film of the present invention is a method for producing an antireflection film in which a hard coat layer (B) and an antireflection layer (C) are sequentially laminated on at least a substrate (A), After the antireflection layer (C) has deposited the (meth) acryloyl compound (D) having a fluorine functional group in the molecule in a vacuum on the hard coat layer (B), it is irradiated with active energy rays, It is formed by curing the (meth) acryloyl compound (D).

  In the present invention, the plastic film (A) is used on the display surface or inside thereof, and is not particularly limited, and a highly transparent film can be used. Examples include polyesters such as PET and PEN, polyolefins such as PE and PP, cycloolefins such as norbornene, celluloses such as TAC, polyether sulfones such as PES, and the like. is not. In particular, when a cellulose-based film such as TAC is used, an antireflection film with high visibility and high reliability can be obtained.

  The hard coat layer (B) of the present invention prevents the base material from being damaged by being formed on the plastic film (A) as a base material, and is a compound having a (meth) acryloyl group in the molecule ( E) and fine particles (F) having a particle diameter of 1 to 10 μm.

  The compound (E) having a (meth) acryloyl group in the molecule can obtain a high surface hardness by irradiating an active energy ray at the time of formation to polymerize the (meth) acryloyl group and take a crosslinked structure. It can be a so-called hard coat component. The compound (E) having a (meth) acryloyl group in the molecule is not particularly limited, but high surface hardness can be obtained when a compound having three or more (meth) acryloyl groups is used. Moreover, what has 1-2 (meth) acryloyl groups can also be used according to purposes, such as adhesiveness and a softness | flexibility.

For example, as the compound (E) having 3 or more (meth) acryloyl groups in the molecule,
(Meth) acrylic polyfunctional monomers such as dipentaerythritol hexa (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, trimethylolpropane triacrylate, trimethylolpropane tetraacrylate, and polyfunctional urethane Acrylate and polyfunctional epoxy acrylate can be used. In particular, when dipentaerythritol hexa (meth) acrylate and pentaerythritol tri (meth) acrylate are used, high surface hardness, scratch resistance, and quick curing can be obtained.

  Examples of the compound having 1 to 2 (meth) acryloyl groups include compounds having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, Compounds having amino groups such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, (meth) acrylic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl hexahydro Compounds having a carboxyl group such as phthalic acid, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate, phenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, etc. (Meth) acrylate having a skeleton, isoamyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, Acrylic monofunctional compounds such as methoxydipropylene glycol (meth) acrylate. And diethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, triethylene di (meth) acrylate , PEG # 200 di (meth) acrylate, PEG # 400 di (meth) acrylate, PEG # 600 di (meth) acrylate, neopentyl di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, etc. And bifunctional epoxy (meth) acrylate and bifunctional urethane acrylate.

  The compounding ratio of the compound having 3 or more (meth) acryloyl groups and 1 to 2 or more (meth) acryloyl compounds is 1 to 50 to 100 parts by weight of the compound having 3 or more (meth) acryloyl groups. ~ 2 to 50 parts by weight of (meth) acryloyl compound can be blended, and if it exceeds 50 parts by weight, the crosslink density may be lowered, so that sufficient surface hardness may not be obtained.

  The fine particles (F) are so-called antiglare agents that form an unevenness on the surface of the hard coat layer (B) and exhibit antiglare properties by scattering light reflected on the surface of the layer. 1-10 micrometers can be used for microparticles | fine-particles (F). Preferably, when 3 to 7 μm is used, high antiglare property and image contrast can be obtained.

  As the fine particles (F), organic fine particles (G) and inorganic fine particles (H) can be used. In either case, there is no particular limitation, and a compound having a difference from the refractive index of the compound (E) having a (meth) acryloyl group in the molecule of less than 0.01 can be used. Preferably, it is less than 0.005, and more preferably, when the difference is 0, high transparency and image contrast can be obtained.

The organic fine particles (G) are not particularly limited, and fine particles that are cross-linked polymers made of acrylic resin, styrene resin, benzoguanine resin, melamine resin, and formaldehyde resin can be used. Fine particles obtained by copolymerizing these resins can also be used. In particular, when fine particles made of an acrylic styrene copolymer resin are used, it is very easy to adjust the refractive index, and high transparency can be achieved.

  The inorganic fine particles (H) are not particularly limited, and silica, alumina, talc, glass filler and the like can be used. In particular, a glass filler having an adjusted refractive index is suitable.

  The fine particles (F) are preferably 1 to 50 parts by weight with respect to 100 parts by weight of the compound (E) having a (meth) acryloyl group in the molecule. When the amount is less than 1 part by weight, sufficient anti-glare property cannot be obtained, and when it exceeds 50 parts by weight, the scattering of the surface becomes strong and the image contrast is lowered. Preferably it is 3-30 weight part, More preferably, it is 5-15 weight part, At this time, the anti-glare film which shows a high contrast can be obtained.

  In the hard coat layer (B) in the present invention, a photoinitiator is preferably blended. The photoinitiator is not particularly limited, and a compound (I) that generates a radical when irradiated with active energy such as ultraviolet rays can be used. For example, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-methyl [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2,2- Dimethoxy-1,2-diphenylethane-1-one, benzophenone, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl 1-propan-1-one, 2-benzyl-2-dimethylamino-1 -(4-Morpholinophenyl) butan-1-one, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and the like can be used.

  In the present invention, the compounding amount of compound (I) is 0.1 to 10 parts by weight, preferably 1 to 7 parts by weight, more preferably 100 parts by weight of compound (E) having a (meth) acryloyl machine in the molecule. Is 1 to 5 parts by weight. When the amount is less than 0.1 part by weight, the hardness of the antiglare coat layer (B) is insufficient, and when it exceeds 10 parts by weight, the hard coat film may be easily cracked. In particular, when the compounding amount of the compound (J) is set to 1 to 5 parts by weight, the hard coat layer (B) is efficiently cured, and cracks can be prevented from being generated.

  The hard coat layer (B) of the present invention can be prepared by dissolving the compound (E), the fine particles (F) and the compound (I) in an appropriate solvent using an appropriate mixing apparatus such as a homomixer. .

  The solvent is not particularly limited, and ketones such as methyl ethyl ketone, acetone and methyl isobutyl ketone, esters such as methyl acetate, ethyl acetate and butyl acetate, aromatic compounds such as toluene and xylene, ethers such as diethyl ether and tetrahydrofuran And alcohols such as methanol, ethanol and isopropanol. The concentration is, for example, about 10 to 90% with respect to the solid content.

  The hard coat layer (B) of the present invention can be applied to the base material by a conventional coating system such as a slot coater, a spin coater, a roll coater, a curtain coater, or screen printing. The film thickness of the film formed at this time is usually about 0.1 to 50 μm, preferably 1 to 25 μm, and more preferably 3 to 10 μm. If it is less than 0.1 μm, sufficient pencil hardness cannot be obtained, and if it is thicker than 50 μm, cracks are likely to occur.

  By making the antireflection layer (C) have a refractive index lower than that of the hard coat layer (B), reflection of light on the film surface can be suppressed.

The (meth) acryloyl compound (D) having a fluorine functional group in the molecule contained in the antireflection layer (C) is aggregated in vacuum and then cured by irradiation with active energy rays to form. Can do. When it is formed by a commonly used wet process, unevenness due to the uneven thickness of the antireflection layer occurs due to the unevenness of the antiglare layer. It is possible to form an antireflection layer that exhibits high coverage and follows unevenness, and an antireflection layer with uniform film thickness can be obtained.

  The antireflection layer (C) can form a cured film by irradiating an active energy ray during film formation to polymerize a (meth) acryloyl group and take a crosslinked structure. When a polymerization initiator is used with the active energy ray to be irradiated, a cured film can be effectively obtained. When EB line is also used, it is preferable to cure without adding a polymerization initiator.

  The film thickness of the antireflection layer (C) only needs to satisfy the general formula nd = λ / 4 (in the range of 450 ≦ λ ≦ 650), and the layer thickness d is controlled in the range of 450 ≦ λ ≦ 650. Thus, an antireflection film having a low luminous reflectance can be obtained.

  Examples of the (meth) acryloyl compound (D) having a fluorine functional group in the molecule include 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3, -tetrafluoropropyl (meth) acrylate, Monofunctional acrylic compounds such as 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 1H, 1H, 2H, 2H-heptadecafluorodecyl (meth) acrylate, 2,2,3,3,4,4,5 , 5,6,6,7,7,8,8,9,9-hexadecafluoro-1,10-decandiol-diepoxy (meth) acrylate, PEPF # 1000 di (meth) acrylate, etc. However, it is not limited to this.

  The (meth) acryloyl compound (D) having a fluorine functional group in the molecule can be blended with a (meth) acrylate compound not containing fluorine, if necessary. For example, when a (meth) acryl polyfunctional monomer such as dipentaerythritol hexa (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, trimethylolpropane triacrylate, or trimethylolpropane tetraacrylate is blended An antireflection layer having high strength can be formed.

  Examples of the present invention will be specifically described below. However, the present invention is not limited to these examples.

  Organic fine particles (refractive index of 1.520) consisting of 100 parts by weight of dipentaerythritol hexaacrylate (Nippon Kayaku Co., Ltd., Kayalld DPHA) as compound (E) and acrylic styrene resin having an average particle size of 5.5 μm as fine particles (F). ) 15 parts by weight and 5 parts by weight of 1-hydroxycyclohexyl phenyl ketone (Ciba Geigy, Irgacure 184) as compound (I) are mixed and dissolved in methyl ethyl ketone and applied to a thickness of 10 μm on a TAC film with a roll coater. Then, after removing the solvent in an oven, it was cured by ultraviolet irradiation to obtain a hard coat layer (B) having a refractive index of 1.520.

  Subsequently, a fluorine-containing acrylic trifunctional compound (FA-17-3L, manufactured by Kyoeisha Chemical Co., Ltd., refractive index 1.426) as a compound (D) is flash-deposited on the hard coat layer (B) in a vacuum. After agglomerating sequentially, electron beam irradiation was performed at an energy of 10 kV to form an antireflection layer (C), thereby obtaining an antireflection film by the production method of the present invention.

About the obtained antireflection film, the pencil hardness, luminous reflectance, transmittance, haze, and surface state were evaluated based on the evaluation methods described below. The results are shown in Table 1.
<Pencil hardness>
This was performed in accordance with JIS K5400.
<Transmissivity>
It measured using the image clarity measuring device [Nippon Denshoku Industries Co., Ltd. make, NDH-2000].
<Haze>
It measured using the image clarity measuring device [Nippon Denshoku Industries Co., Ltd. make, NDH-2000].
<Visual reflectance>
Using an automatic spectrophotometer (U-4000, manufactured by Hitachi, Ltd.), the luminous reflectance was measured from the spectral reflectance. At the time of measurement, the surface opposite to the coated surface was matted and black paint was applied, and antireflection treatment from the back surface side was performed.
<Image contrast>
The contrast between the black image and the white image was visually evaluated.
<Surface condition>
In-plane unevenness was evaluated visually.

  80 parts by weight of pentaerythritol triacrylate (manufactured by Nippon Kayaku Co., Ltd., Kayrad PET-30) and 20 parts by weight of 1,4-hexanediol diacrylate (manufactured by Kyoeisha, Light Acrylate 1.6HX-A) as the compound (E) A hard coat layer having a refractive index of 1.500 comprising 30 parts by weight of a glass filler (refractive index of 1.502) having an average particle diameter of 5.0 μm as fine particles (F), and a fluorine group-containing diacrylate (FA) as the compound (D) -18, manufactured by Kyoeisha Chemical Co., Ltd., with a refractive index of 1.367) was obtained in the same manner as in Example 1 to obtain an antireflection film by the production method of the present invention, and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

As a comparative example for comparing the performance with the antireflection film by the production method of the present invention,
A refractive index of 1. 100 parts by weight of dipentaerythritol hexaacrylate as the compound (A) and 10 parts by weight of organic fine particles (refractive index of 1.520) made of acrylic styrene resin having an average particle size of 5.5 μm as the fine particles (E) A 520 hard coat layer was formed. Subsequently, 100 parts by weight of a fluorine group-containing diacrylate (FA-18, manufactured by Kyoeisha Chemical Co., Ltd., refractive index 1.367) as a compound (D) and 1-hydroxycyclohexyl phenyl ketone (as a photoinitiator) on the hard coat layer. 5 parts by weight of Ciba Geigy, Irgacure 184) is mixed and dissolved in methyl ethyl ketone, coated on a TAC film with a roll coater to a thickness of 0.1 μm, and after removing the solvent in an oven, cured by UV irradiation to prevent reflection. After forming a film and obtaining an antireflection film, the same evaluation as in Example 1 was performed. The evaluation results are shown in Table 1.

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  From Table 1, the antireflection film according to the production method of the present invention obtained in Examples 1 and 2 has a low luminous reflectance, a good surface state, and excellent antiglare properties, surface hardness, and contrast. In addition, the film had high uniformity in the surface with no unevenness in film thickness. On the other hand, the antireflection film obtained in Example 3 as a comparative example had particularly noticeable unevenness in the film thickness.

Claims (4)

It is a method for producing an antireflection film in which a hard coat layer (B) and an antireflection layer (C) are sequentially laminated on at least a substrate (A),
The antireflection layer (C), on the hard coat layer (B), after deposited by flash evaporation method with a fluorine functional group in the molecule in vacuum (meth) acryloyl compound (D), an active energy ray Is formed by curing the (meth) acryloyl compound (D), and a method for producing an antireflection film.   The hard coat layer (B) includes a compound (E) having a (meth) acryloyl group in the molecule and a fine particle (F) having a particle diameter of 1 μm to 10 μm and having a (meth) acryloyl group in the molecule ( The method for producing an antireflection film according to claim 1, wherein the difference in refractive index between E) and the fine particles (F) is 0.01 or less.   The method for producing an antireflection film according to claim 1 or 2, wherein the fine particles (F) are organic resin fine particles (G). The method for producing an antireflection film according to claim 1, wherein the fine particles (F) are inorganic fine particles (H).