JP2011081120A - Antireflection film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antireflection film with low reflection and exhibiting black tightness by making dense the arrangement of low refractive index particle contained in a low refractive index layer. <P>SOLUTION: The antireflection film having the low refractive index layer laminated at least on one side of a transparent base material is formed using a low refractive index coating agent containing an organic modified poly siloxane of a leveling agent and at least a low refractive index silica particle having void inside the particles in an ionizing radiation curing type material. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an antireflection film and a method for producing the same, and in particular, to an image display device such as a CRT display, liquid crystal display, plasma display, EL display, etc. The present invention relates to an antireflection film.

  In general, an image display apparatus has a problem that it is difficult to recognize an image when external light is reflected on a display screen. Furthermore, recently, opportunities to be taken not only indoors but also outdoors have increased, and reflection of external light on the display screen has become a more important problem.

  Reflection on the display screen is solved by a method of reducing the reflectance. As the technique, a method of laminating layers having different refractive indexes is used for the antireflection film, and the antireflection performance improves as the number of layers increases.

  However, since the cost increases with an increase in the number of layers, a two-layer or three-layer laminate that exhibits better antireflection performance than a single layer while suppressing the cost is often used. In addition, there is a known method of putting fine particles containing voids inside the layer having a low refractive index. However, if the voids are excessively increased, the mechanical strength of the antireflection film decreases, and the surface of the antireflection film is scratch-resistant. There is a reciprocal relationship that the nature deteriorates.

  When manufacturing an antireflection film, dry coating methods such as physical vapor deposition (PVD) and chemical vapor deposition (CVD) and wet coating methods are known. In the case of the dry coating method, there is an advantage that the film thickness of the low refractive index layer and the high refractive index layer can be precisely controlled, but since the film formation is performed in a vacuum, the productivity is low and it is not suitable for mass production. There's a problem. On the other hand, the wet coating method can increase the area, continuously produce, and reduce the cost.

JP-A-11-189621 Japanese Patent Laid-Open No. 11-228631 JP 2000-313709 A

  For example, a low refractive index layer is formed on the surface of a transparent substrate using a coating liquid containing an ultraviolet curable material, low refractive index particles, and a solvent. It is effective to increase the particle diameter of the porous silica fine particles used for the low refractive index layer provided in the layer, or to use a layer containing a fluorine-based material. However, when a fluorine-based material is used, there are concerns such as deterioration of surface area and show-through.

  The show-through is when the antireflection layer or low refractive index layer forming surface produced by roll-to-roll comes into contact with the other surface (antireflection layer non-forming surface or low refractive index layer non-forming surface). When the fluorine-based material component adheres to the back surface of the antireflection film, there is a problem that not only the film characteristics of the antireflection film are deteriorated but also a great problem is caused in the subsequent processing steps.

  When an antireflection film is used as a display member, a polarizing plate is attached to the back surface of the display member and an antireflection film is placed on the front surface of the display. Therefore, the performance required for the antireflection film includes optical characteristics, mechanical characteristics, and antifouling It must have sufficient performance in all sexes. In particular, in order to suppress the reflection, the low reflection and the tightness of black accompanying the recent sharpening of the image are important.

  An object of the present invention is to obtain an antireflection film having a low refractive index and a black tightening by densely arranging low refractive index particles contained in a low refractive index layer.

  In order to solve the above-mentioned problems, the invention according to claim 1 is directed to an antireflective film in which a low refractive index layer is laminated on at least one surface of a transparent substrate. An antireflective film formed using a low refractive index coating agent comprising siloxane and low refractive index silica particles having voids at least inside the particles.

  In the invention according to claim 2 of the present invention, the addition amount of the organically modified polysiloxane is 0.5 parts by weight or more and 2.5 parts by weight or less, and the surface tension change is 2 before and after the addition of the organically modified polysiloxane. The antireflection film according to claim 1, wherein the antireflection film has a surface roughness change of 0.8 nm or more and 2.2 nm or less in a range of from 0.0 mN / m to 6.0 mN / m.

  According to a third aspect of the present invention, in the antireflection film, the surface roughness (Ra) is 0.3 nm or more and 1.5 nm or less, and the average luminous reflectance is 0.4% or more and 0.00. It is 8% or less, It is an antireflection film of Claim 1 characterized by the above-mentioned.

  The invention according to claim 4 of the present invention comprises the antireflection film according to any one of claims 1 to 3, and a first polarizing plate provided on the low refractive index layer non-formation surface of the antireflection film. It is the anti-reflective polarizing plate characterized.

  The invention according to claim 5 of the present invention comprises, in order from the observer side, the antireflective polarizing plate according to claim 4, a liquid crystal cell, a second polarizing plate, and a backlight unit in this order. A transmissive liquid crystal display characterized in that a liquid crystal cell is held on the side of the low polarizing layer non-formation surface of the polarizing plate.

  ADVANTAGE OF THE INVENTION According to this invention, an antireflection film and its manufacturing method can be provided using the low refractive index coating agent with a low average luminous reflectance and a feeling of black tightening.

It is a cross-sectional schematic diagram of the antireflection film of one Example of this invention. It is a cross-sectional schematic diagram of the anti-reflective polarizing plate using the anti-reflective film of one Example of this invention. It is a cross-sectional schematic diagram which shows a transmissive liquid crystal display provided with the antireflection film of one Example of this invention.

  The antireflection film of the present invention will be described.

  The cross-sectional schematic diagram of the antireflection film (10) of the present invention is shown in FIG.

  As shown in FIG. 1, the antireflection film (10) according to the embodiment of the present invention has a hard coat layer (12) on the first transparent substrate (11) and a low coat on the hard coat layer (12). A refractive index layer (13) is provided. The outermost surface of the antireflection film (10) is a low refractive index layer (13). In order to exhibit the antireflection performance only with the low refractive index layer (13), the low refractive index layer (13) having a layer thickness having an optical film thickness that is ¼ of the wavelength in the visible light region is provided. . By providing a low-refractive-index layer (13) with a layer thickness that has an optical thickness that is ¼ of the wavelength in the visible light region, reflection of external light incident on the surface of the antireflection film (10) is suppressed. can do.

  Further, by providing the hard coat layer (12) on the first transparent substrate (11), a high surface hardness can be imparted to the surface of the antireflection film (10), and the reflection is excellent in scratch resistance. It can be set as a prevention film (10).

  In addition, the antireflection film (10) according to the embodiment of the present invention is not limited to the configuration of the antireflection film (10) shown in FIG. 1, and for example, a low refractive index layer (13) and a hard coat. By providing a high refractive index layer between the layers (12) and forming a laminated structure of the low refractive index layer (13) and the high refractive index layer, it is possible to impart high antireflection performance to the antireflection film (10). it can.

  Further, by providing an antistatic layer between the low refractive index layer (13) and the hard coat layer (12) and between the hard coat layer (12) and the first substrate (11), an antireflection film ( 10) can be provided with antistatic performance. Moreover, you may provide antistatic property by adding a conductive material to a hard-coat layer (12) or a high refractive index layer.

  First, the transparent substrate (11, 22, 41, 42) will be described.

  As the transparent substrate (11, 22, 41, 42) of the present invention, a plastic film can be suitably used. For example, polyethylene terephthalate (PET), polyethersulfone (PES), polystyrene (PS), polyethylene naphthalate (PEN), polyarylate (PAR), polyetheretherketone (PEEK), polycarbonate (PC), polyethylene (PE ), Polyamide (PA) such as polypropylene (PP) and nylon 6, cellulose resin films such as polyimide (PI) and triacetyl cellulose (TAC), fluorine resins such as polyurethane (PUR) and polytetrafluoroethylene, poly Vinyl compounds such as vinyl chloride (PVC), polyacrylic acid (PMMA), polyacrylic acid esters, polyacrylonitrile, addition polymers of vinyl compounds, polymethacrylic acid, polymethacrylic acid esters, polyvinylidene chloride, etc. Vinylidene compounds, vinylidene fluoride / trifluoroethylene copolymers, vinyl compounds such as ethylene / vinyl acetate copolymers or copolymers of fluorine compounds, polyethers such as polyethylene oxide, epoxy resins, polyvinyl alcohol (PVA), Polyvinyl butyral or the like can be used, but is not limited thereto, and any material that has excellent mechanical strength and dimensional stability may be used. In order to improve adhesion, corona treatment, low temperature plasma treatment, or the like may be performed as pretreatment.

  Among the transparent substrates described above, it is particularly preferable to use triacetyl cellulose. Since the triacetyl cellulose film has little birefringence and good transparency, it can be suitably used when the antireflection film of the present invention is used in a liquid crystal display. The refractive index of the triacetyl cellulose film is about 1.50, which is lower than that of other transparent substrates. For example, a polyethylene terephthalate film widely used as a transparent substrate is about 1.60.

  The thickness of the transparent substrate is not particularly limited, but considering the suitability as the antireflection film (10) and the lamination of a plurality of layers, the thickness of the transparent substrate is 20 μm or more and 200 μm or less. It is preferable to be within the range. In particular, when triacetyl cellulose is used, it is preferable to use a thickness of 35 μm or more and 80 μm or less.

  Next, the hard coat layer (12) will be described.

  A hard coat layer (12) is formed on the surface of the first transparent base material (11). The hard coat layer (12) improves the surface hardness of the first transparent base material (11), and a load such as a pencil. It is possible to prevent scratches due to such scratches, and it is possible to suppress cracks in the low refractive index layer (13) due to the bending of the first transparent base material (11), and the antireflection film (10). The mechanical strength of can be improved.

  The hard coat layer (12) is formed by applying a coating liquid for forming the hard coat layer (12) containing an ionizing radiation curable material onto the first transparent base material (11). A hard coat is formed by forming a coating film on the top, drying the coating film as necessary, and then irradiating ionizing radiation such as ultraviolet rays and electron beams to cure the ionizing radiation curable material. The hard coat layer (12) can be formed by a roll-to-roll method.

  As the ionizing radiation curable material added to the coating liquid for forming the hard coat layer (12), an acrylic material can be used. The acrylic material is synthesized from a monofunctional or polyfunctional (meth) acrylate compound such as acrylic acid or methacrylic acid ester of polyhydric alcohol, diisocyanate and polyhydric alcohol, and hydroxyester of acrylic acid or methacrylic acid. Such a polyfunctional urethane (meth) acrylate compound can be used. Besides these, polyether resins having an acrylate functional group, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and the like can be used.

  In the embodiment of the present invention, “(meth) acrylate” indicates both “acrylate” and “methacrylate”. For example, “urethane (meth) acrylate” indicates both “urethane acrylate” and “urethane methacrylate”.

  Examples of the monofunctional (meth) acrylate compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl ( (Meth) acrylate, t-butyl (meth) acrylate, glycidyl (meth) acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) ) Acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, benzyl (Meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phosphoric acid (meth) acrylate, ethylene oxide modified phosphoric acid (meth) acrylate, phenoxy (meta) ) Acrylate, ethylene oxide modified phenoxy (meth) acrylate, propylene oxide modified phenoxy (meth) acrylate, nonylphenol (meth) acrylate, ethylene oxide modified nonylphenol (meth) acrylate, propylene oxide modified nonylphenol (meth) acrylate, methoxydiethylene glycol (meth) Acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypropylene glycol (meth) acrylate 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth) acryloyloxyethyl hydrogen phthalate, 2- (meth) acryloyloxypropyl hydrogen Phthalate, 2- (meth) acryloyloxypropyl hexahydrohydrogen phthalate, 2- (meth) acryloyloxypropyl tetrahydrohydrogen phthalate, dimethylaminoethyl (meth) acrylate, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate , Hexafluoropropyl (meth) acrylate, octafluoropropyl (meth) acrylate, octafluoropropyl (meth) acrylate, 2 -Adamantane derivatives mono (meth) acrylates such as adamantyl acrylate having a monovalent mono (meth) acrylate derived from adamantane and adamantanediol.

  Examples of the bifunctional (meth) acrylate compound include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, and nonanediol di (meth). Acrylate, ethoxylated hexanediol di (meth) acrylate, propoxylated hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di ( (Meth) acrylate, neopentyl glycol di (meth) acrylate, ethoxylated neopentyl glycol di (meth) acrylate, tripropylene glycol Di (meth) acrylate, di (meth) acrylate, such as hydroxypivalic acid neopentyl glycol di (meth) acrylate.

  Examples of the trifunctional or higher functional (meth) acrylate compound include trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, and tris 2-hydroxyethyl. 3 such as tri (meth) acrylate such as isocyanurate tri (meth) acrylate and glycerol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate Functional (meth) acrylate compounds, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra Trifunctional or more polyfunctional (meth) such as (meth) acrylate, dipentaerythritol penta (meth) acrylate, ditrimethylolpropane penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane hexa (meth) acrylate Examples thereof include acrylate compounds and polyfunctional (meth) acrylate compounds in which a part of these (meth) acrylates is substituted with an alkyl group or ε-caprolactone.

  Among acrylic materials, polyfunctional urethane acrylate is preferably used because the desired molecular weight and molecular structure can be designed and the physical properties of the formed hard coat layer (12) can be easily balanced. be able to. The urethane acrylate is obtained by reacting a polyhydric alcohol, a polyvalent isocyanate, and a hydroxyl group-containing acrylate. Specifically, manufactured by Kyoeisha Chemical Co., Ltd., UA-306H, UA-306T, UA-306l, etc., manufactured by Nippon Synthetic Chemical Co., Ltd. -7650B, etc., manufactured by Shin-Nakamura Chemical Co., Ltd., U-4HA, U-6HA, UA-100H, U-6LPA, U-15HA, UA-32P, U-324A, etc., manufactured by Daicel UCB, Ebecryl-1290, Ebecryl -1290K, Ebecryl-5129, etc., manufactured by Negami Kogyo Co., Ltd., UN-3220HA, UN-3220HB, UN-3220HC, UN-3220HS, and the like, but are not limited thereto.

  When the coating liquid for forming the hard coat layer (12) is cured by ultraviolet rays, a photopolymerization initiator is added to the coating liquid for forming the hard coat layer (12). Any photopolymerization initiator may be used as long as it generates radicals when irradiated with ultraviolet rays. For example, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones are used. Can do. The addition amount of the photopolymerization initiator is 0.1 parts by weight or more and 10 parts by weight or less, preferably 1 part by weight or more and 7 parts by weight or less with respect to 100 parts by weight of the ionizing radiation curable material.

  Furthermore, a solvent and various additives can be added to the coating liquid for forming the hard coat layer (12) as necessary. Solvents include aromatic hydrocarbons such as toluene, xylene, cyclohexane and cyclohexylbenzene, hydrocarbons such as n-hexane, dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, dioxane, dioxolane, and trioxane. , Ethers such as tetrahydrofuran, anisole and phenetole, and ketones such as methyl isobutyl ketone, methyl butyl ketone, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, and methylcyclohexanone , Ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate Esters such as acetic acid n- pentyl, and γ- butyrolactone, furthermore, methyl cellosolve, cellosolve, butyl cellosolve, is suitably selected from such cellosolves such as cellosolve acetate in consideration of the coating proper and the like. In addition, a surface adjusting agent, a refractive index adjusting agent, an adhesion improver, a curing agent, and the like can be added to the coating liquid as additives.

  In addition, the antireflection film (10) is easily charged with static electricity and may cause a problem in appearance due to adhesion of dust. Therefore, a conductive material for preventing static electricity can be added to impart antistatic performance. For example, antistatic properties can be imparted by dispersing metal oxide fine particles in the hard coat layer (12). As the metal oxide fine particles, ATO (antimony-doped tin oxide), ITO (indium tin oxide oxide), tin oxide, titanium oxide, antimony pentoxide and the like used for the transparent conductive film can be used. Further, a quaternary ammonium salt or a conductive polymer can be used as the conductive material.

  As a coating method for forming the hard coat layer (12), a roll coater, a reverse roll coater, a gravure coater, a micro gravure coater, a knife coater, a bar coater, a wire bar coater, a die coater, and a dip coater The method can be used.

  After the coating liquid for forming the hard coat layer (12) is applied to the surface of the first transparent substrate (11), the solvent in the coating film on the surface of the first transparent substrate (11) is removed as necessary. In order to do so, a drying process is provided.

  The coating film on the surface of the first transparent substrate (11) is cured by irradiating active energy rays to form a hard coat layer (12). As the active energy rays, ultraviolet rays, electron beams, gamma rays, or the like can be used. When an electron beam or a gamma ray is used as the active energy ray, the coating liquid for forming the hard coat layer (12) does not necessarily need to contain a photopolymerization initiator or a photoinitiator aid. As a light source for generating ultraviolet rays, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, an electrodeless discharge tube, or the like can be used. Moreover, as an electron beam, the electron beam emitted from various electron beam accelerators, such as a Cockloftwald type, a bande graph type, a resonance transformation type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type, can be used.

  In the antireflection film of the present invention, the thickness of the hard coat layer to be formed is preferably 5 μm or more and 12 μm or less, and the pencil hardness is H or more in order to have physical scratch resistance. Is preferred.

  Next, the low refractive index layer (13) will be described.

  A low refractive index layer (13) is formed on the surface of the hard coat layer (12) formed on the surface of the first transparent substrate (11).

  The low refractive index layer (13) is formed by applying a coating solution for forming containing an ionizing radiation curable material, low refractive index particles, a leveling agent, a silicone material having water repellency, and a solvent. It forms by the coating process to form, the drying process which dries a coating film, and the ultraviolet irradiation process which irradiates an ultraviolet-ray to a coating film.

  As the ionizing radiation curable material added to the coating liquid for forming the low refractive index layer (13), an acrylic material can be used as in the case of the coating liquid for forming the hard coat layer (12). Acrylic materials include polyfunctional (meth) acrylate compounds such as polyhydric alcohol acrylic acid or methacrylic acid ester, simple compounds synthesized from diisocyanate and polyhydric alcohol, acrylic acid or methacrylic acid hydroxy ester, and the like. A functional or polyfunctional urethane (meth) acrylate compound can be used. Besides these, polyether resins having an acrylate functional group, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and the like can be used.

  Examples of the monofunctional (meth) acrylate compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl ( (Meth) acrylate, t-butyl (meth) acrylate, glycidyl (meth) acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) ) Acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, benzyl (Meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phosphoric acid (meth) acrylate, ethylene oxide modified phosphoric acid (meth) acrylate, phenoxy (meta) ) Acrylate, ethylene oxide modified phenoxy (meth) acrylate, propylene oxide modified phenoxy (meth) acrylate, nonylphenol (meth) acrylate, ethylene oxide modified nonylphenol (meth) acrylate, propylene oxide modified nonylphenol (meth) acrylate, methoxydiethylene glycol (meth) Acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypropylene glycol (meth) acrylate 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth) acryloyloxyethyl hydrogen phthalate, 2- (meth) acryloyloxypropyl hydrogen Phthalate, 2- (meth) acryloyloxypropyl hexahydrohydrogen phthalate, 2- (meth) acryloyloxypropyl tetrahydrohydrogen phthalate, dimethylaminoethyl (meth) acrylate, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate , Hexafluoropropyl (meth) acrylate, octafluoropropyl (meth) acrylate, octafluoropropyl (meth) acrylate, 2 -Adamantane derivatives mono (meth) acrylates such as adamantyl acrylate having a monovalent mono (meth) acrylate derived from adamantane and adamantanediol.

  Examples of the bifunctional (meth) acrylate compound include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, and nonanediol di (meth). Acrylate, ethoxylated hexanediol di (meth) acrylate, propoxylated hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di ( (Meth) acrylate, neopentyl glycol di (meth) acrylate, ethoxylated neopentyl glycol di (meth) acrylate, tripropylene glycol Di (meth) acrylate, di (meth) acrylate, such as hydroxypivalic acid neopentyl glycol di (meth) acrylate.

  Examples of the trifunctional or higher functional (meth) acrylate compound include trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, and tris 2-hydroxyethyl. 3 such as tri (meth) acrylate such as isocyanurate tri (meth) acrylate and glycerol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate Functional (meth) acrylate compounds, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra Trifunctional or more polyfunctional (meth) such as (meth) acrylate, dipentaerythritol penta (meth) acrylate, ditrimethylolpropane penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane hexa (meth) acrylate Examples thereof include acrylate compounds and polyfunctional (meth) acrylate compounds in which a part of these (meth) acrylates is substituted with an alkyl group or ε-caprolactone.

Among acrylic materials, a polyfunctional urethane acrylate can be suitably used because the desired molecular weight and molecular structure can be designed and the physical properties of the hard coat layer to be formed can be easily balanced. . The urethane acrylate is obtained by reacting a polyhydric alcohol, a polyvalent isocyanate, and a hydroxyl group-containing acrylate.
Specifically, Kyoeisha Chemical Co., Ltd., UA-306H, UA-306T, UA-306l, etc., Nippon Synthetic Chemical Co., Ltd., UV-1700B, UV-6300B, UV-7600B, UV-7605B, UV-7640B, UV -7650B, etc., Shin-Nakamura Chemical Co., Ltd., U-4HA, U-6HA, UA-100H, U-6LPA, U-15HA, UA-32P, U-324A, etc., Daicel UCB, Ebecryl-1290, Ebecryl -1290K, Ebecryl-5129, etc., manufactured by Negami Kogyo Co., Ltd., UN-3220HA, UN-3220HB, UN-3220HC, UN-3220HS, and the like, but are not limited thereto.

The low refractive index particles added to the coating liquid for forming the low refractive index layer (13) include LiF, MgF, 3NaF.AlF3 or AlF3 (all having a refractive index of 1.4), or Na ₃ AlF ₆ (ice crystal). Low refractive index particles made of a low refractive material such as stone and a refractive index of 1.33) can be used.

  In the low refractive index particles, low refractive index particles having voids inside the particles can be suitably used. In the particles having voids inside the particles, the void portion can have the refractive index of air (≈1), so that the particles can have low refractive index having a very low refractive index. Specifically, low refractive index silica particles having voids inside can be used.

  The low refractive index silica particles added to the coating liquid for forming the low refractive index layer (13) preferably have a particle size of 1 nm to 100 nm. Furthermore, the particle size is preferably in the range of 60 nm to 80 nm.

  When the particle diameter of the low refractive index silica particles exceeds 100 nm, light is remarkably reflected by Rayleigh scattering, and the low refractive index layer (13) is whitened and the transparency of the antireflection film (10) tends to be lowered. . On the other hand, when the particle diameter of the low refractive index silica particles is less than 1 nm, problems such as particle non-uniformity in the low refractive index layer (13) due to aggregation of the particles occur.

  In the case of low refractive index silica particles having voids inside, the voids can be made to have a refractive index of air (≈1), so that low refractive index silica particles having a very low refractive index can be obtained. it can. As the low refractive index silica particles having voids therein, porous silica particles or shell-structured silica particles can be used.

  Moreover, as a space | gap of the low refractive index silica particle which has a space | gap inside, it is preferable that they are 20 nm or more and 80 nm or less. This is because, when the gap exceeds 80 nm, sufficient scratch resistance cannot be obtained and the antireflection film provided on the display surface is not suitable. On the other hand, when the gap is less than 20 nm, the refractive index is 1.45 or more, and the average luminous reflectance is 1.0% or more.

  In addition, as an example of the low refractive index silica particles having voids inside, the refractive index is 1.35 lower than the refractive index of glass 1.45 while maintaining the spherical shape, the radius is 20 nm or more and 25 nm or less, A spherical structure of density (ρ1) is in the central part, and the periphery is covered with layers of different densities (ρ2) having a thickness of 10 nm to 15 nm, and the value of (ρ1 / ρ2) is 0.5, 0.1, 0.0, and the center part of the low refractive index silica particle is a structural model that has a density of about 1/10 of the external silica.

  As a leveling agent added to the coating liquid for forming the low refractive index layer (13), it is preferable to use an organically modified polysiloxane. Furthermore, it is preferable to use a polyether-modified polydimethylsiloxane solution represented by the chemical formula (Chemical Formula 1).

  In addition to the above, as the leveling agent, polydimethylsiloxane having a polyether-modified acrylic group, polydimethylsiloxane having a polyester-modified acrylic group, polyether-modified hydroxyl group-containing polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane and the like can be mentioned. It is done.

  Moreover, the surface tension in the drying process can be lowered by adding organically modified polysiloxane. The addition amount of the organically modified polysiloxane is preferably in the range of 0.5 to 2.0 parts by weight. When the addition amount of the organically modified polysiloxane is 0.5 parts by weight or less, the decrease in surface tension is small and the surface roughness is not affected. On the other hand, when the addition amount of the organically modified polysiloxane is 2.0 parts by weight or more, bleeding of the leveling agent on the surface of the low refractive index layer and whitening of the surface occur.

  In addition, before and after the addition of the organically modified polysiloxane, the surface tension change is in the range of 2.0 mN / m to 6.0 mN / m and the surface roughness change is in the range of 0.8 nm to 2.2 nm. It is preferable to be within. When the change in surface tension is 2.0 mN / m or less, the effect on black tightening is small and the image appears to be blurred white. On the other hand, when the change in surface tension is 6.0 mN / m or more, surface defects that occur due to susceptibility to liquid sag and apparatus vibrations occur.

  Furthermore, when the change in surface roughness is 0.8 nm or less, the effect on black tightening is small, and white blur appears. On the other hand, when the surface roughness change is 2.2 nm or more, the surface roughness of the film itself is close, so that the effect is small.

  Examples of silicone materials having water repellency that are added to the coating liquid for forming the low refractive index layer (13) include alkyl aralkyl-modified silicone oil, alkyl-modified silicone oil, polyether-modified silicone oil, and alkyl polyether-modified silicone oil. It is preferable to use it.

  In addition, as the silicone material having water repellency, an organosilicon compound which does not contain fluorine and does not have a (meth) acryl group can also be used. Specifically, an alkyl alkoxysilane compound, a silane siloxane compound, a silane compound containing a polyester group, a silane compound having a polyether group, or a siloxane compound can also be used.

  A solvent is added to the coating liquid for forming the low refractive index layer (13). Solvents include aromatic hydrocarbons such as toluene, xylene, cyclohexane and cyclohexylbenzene, hydrocarbons such as n-hexane, dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, dioxane, dioxolane, and trioxane. , Ethers such as tetrahydrofuran, anisole and phenetole, and ketones such as methyl isobutyl ketone, methyl butyl ketone, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, and methylcyclohexanone , Ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate Coating suitability among esters such as n-pentyl acetate and γ-ptyrolactone, cellosolves such as methyl cellosolve, cellosolve, butyl cellosolve and cellosolve acetate, and alcohols such as methanol, ethanol and isopropyl alcohol. It chooses suitably in consideration. A photopolymerization initiator is also added.

  Any photopolymerization initiator may be used as long as it generates radicals when irradiated with ultraviolet rays. For example, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones are used. Can do. The addition amount of the photopolymerization initiator is 0.1 parts by weight or more and 10 parts by weight or less, preferably 1 part by weight or more and 7 parts by weight or less with respect to 100 parts by weight of the ionizing radiation curable material.

  The low refractive index layer (13) is for forming a low refractive index layer (13) containing an ionizing radiation curable material, low refractive index silica particles, a leveling agent, a silicone material having water repellency and a solvent. It is formed by an application process for applying a coating liquid to form a coating film, a drying process for drying the coating film, and an ultraviolet irradiation process for irradiating the coating film with ultraviolet rays. The film thickness of the low refractive index layer is preferably in the range of 95 nm to 110 nm.

  In the method for producing an antireflection film (10) of the present invention, the low refractive index layer (13) is formed by a roll-to-roll method. As a method for applying the coating liquid for forming the low refractive index layer (13), as in the case of the coating liquid for forming the hard coat layer (12), a roll coater, reverse roll coater, gravure coater, micro gravure coater, knife A coating method using a coater, bar coater, wire bar coater, die coater or dip coater can be used.

  The low refractive index layer (13) is formed by curing the coating film by irradiating the coating film on the hard coat layer (12) with ultraviolet rays. As a light source for generating ultraviolet rays, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, an electrodeless discharge tube, or the like can be used.

  The antireflection film (10) preferably has an average luminous reflectance in the range of 0.4% to 0.8% and a total light transmittance of 95% or more. When the average luminous reflectance exceeds 0.8%, the antireflection performance is lowered, and reflection of external light tends to occur. On the other hand, when the average luminous reflectance is less than 0.4%, it is necessary to laminate a high refractive index layer and a low refractive index in order to realize high antireflection performance, resulting in high cost. Further, when the total light transmittance is less than 95%, it becomes unsuitable to be provided on the surface of an image device such as a transmissive liquid crystal display.

The average luminous reflectance is obtained from the spectral reflectance curve on the surface of the low refractive index layer. The spectral reflectance curve of the antireflective film of the present invention is obtained after the surface opposite to the low refractive index layer of the antireflective film is matted with a black paint, and from the direction perpendicular to the surface of the low refractive index layer. The incident angle is set to 5 degrees, a C light source is used as the light source, and the angle is obtained under conditions of a 2 degree visual field. The average luminous reflectance is a reflectance value obtained by calibrating the reflectance of each wavelength of visible light with the relative luminous sensitivity and averaging it. At this time, the photopic standard relative visual sensitivity is used as the specific visual sensitivity.

  The surface roughness (Ra) is preferably in the range of 0.3 nm to 1.5 nm. When the surface roughness is 0.3 nm or less, the effect is small because the surface roughness of the film itself is close to. On the other hand, when the surface roughness is 1.5 nm or more, black tightening is weak and white blurring occurs. It looks like.

  Next, the 1st polarizing plate (20) using the antireflection film (10) of this invention is demonstrated.

  FIG. 2 illustrates an antireflection polarizing plate (210) using the antireflection film (10) of the present invention.

  The antireflective polarizing plate (20) of FIG. 2 is an antireflective film in which a hard coat layer (12) and a low refractive index layer (13) are provided in this order on one surface of the first transparent substrate (11). (10), which is an antireflective polarizing plate (210) comprising a first polarizing layer (23) and a second transparent substrate (22) in this order on the low refractive index layer non-forming surface side.

  The antireflection film (10) according to the embodiment of the present invention can be used as a part of a display member or an image device.

  The structure of the transmissive liquid crystal display using the antireflection film of the present invention will be described.

  FIG. 3 shows a transmissive liquid crystal display using the antireflection film of the present invention. In the transmissive liquid crystal display of FIG. 3A, the first polarizing plate (20) in which the antireflection film (10) of the present invention is bonded to one surface is provided on the surface where the low refractive index layer is not formed. An antireflection polarizing plate (200), a liquid crystal cell (30), a second polarizing plate (40), and a backlight unit (50) are provided in this order. At this time, the antireflection film (10) side becomes the observation side, that is, the display surface.

  In Fig.3 (a), it is a transmissive | pervious liquid crystal display provided with the transparent base material (11) of an antireflection film (10), and the transparent base material of a 1st polarizing plate (20) separately.

  The backlight unit (50) includes a light source and a light diffusion plate. The liquid crystal cell (30) has a structure in which an electrode is provided on one transparent substrate, an electrode and a color filter are provided on the other transparent substrate, and liquid crystal is sealed between both electrodes. In the first and second polarizing plates provided so as to sandwich the liquid crystal cell (30), the polarizing layer (23, 43) is sandwiched between the transparent base materials (21, 22, 41, 42). It has become.

  Moreover, in FIG.3 (b), the antireflective film (10) provided with the low-refractive-index layer (13) on one surface of the transparent base material (11), and the low-refractive-index layer of the said antireflective film A non-formation surface is provided with a polarizing layer (23) and a transparent substrate (22) in this order to form an antireflection polarizing plate (210), and the antireflection polarizing plate (210), liquid crystal cell (30), Two polarizing plates (40) and a backlight unit (50) are provided in this order. At this time, the low refractive index layer (13) side of the antireflection film (10) becomes the observation side, that is, the display surface.

  In FIG.3 (b), the antireflection property provided with the polarizing layer (23) and the transparent base material (22) in this order as a 1st polarizing plate in the antireflection layer non-formation surface of an antireflection film. It is a transmissive liquid crystal display provided with a polarizing plate (210).

  In FIG. 3B as well, as in FIG. 3A, the backlight unit (50) includes a light source and a light diffusion plate. The liquid crystal cell has a structure in which an electrode is provided on one transparent substrate, an electrode and a color filter are provided on the other transparent substrate, and liquid crystal is sealed between both electrodes. In the first and second polarizing plates provided so as to sandwich the liquid crystal cell (30), the polarizing layer (23, 43) is sandwiched between the transparent base materials (11, 22, 41, 42). It has become.

  Moreover, in the transmissive liquid crystal display of this invention, you may provide another functional member. Other functional members include, for example, a diffusion film, a prism sheet, a brightness enhancement film for effectively using light emitted from a backlight, and a phase difference film for compensating for a phase difference between a liquid crystal cell and a polarizing plate. However, the transmissive liquid crystal display of the present invention is not limited to these.

  As described above, a transmissive liquid crystal display using the antireflection film of the present invention is manufactured.

  Examples of the present invention will be described below. In addition, this invention is not limited to an Example.

Example 1
As shown in FIGS. 1 to 3, a triacetyl cellulose film having a thickness of 80 μm was prepared as the first transparent substrate (11).

The hard coat layer (12) formed on the surface of the first transparent substrate (11) is made by Nippon Synthetic Chemical Co., Ltd. as a ionizing radiation curable material, 100 parts by weight of purple light, UV-7605B, a photopolymerization initiator. 4 parts by weight of Irgacure 184 manufactured by Ciba Geigy Co., 50 parts by weight of methyl acetate as a solvent and 50 parts by weight of 2-butanone were mixed to prepare a coating solution for forming the hard coat layer (12). A coating liquid for forming a hard coat layer (12) is applied onto a triacetyl cellulose film which is a transparent substrate (11), dried, and an irradiation dose of 300 mJ using an ultraviolet irradiation device (Fusion UV System Japan, light source H bulb). A transparent hard coat layer (12) having a dry film thickness of 10 μm was formed by irradiating with ultraviolet rays at / m ² .

  Furthermore, in the coating liquid for forming the low refractive index layer (13) formed on the surface of the hard coat layer (12), 0.5 part by weight of an organically modified polysiloxane as a leveling agent and low refractive index silica particles ( 36 parts by weight of an average particle size of 80 nm), 1.6 parts by weight of dipentaerythritol hexaacrylate (DPHA) as an ionizing radiation curable material, and 0.2% of TSF44 manufactured by Toshiba GE Silicone as a silicone material having water repellency. 0.2 parts by weight of Ciba Japan Co., Ltd. Irgacure 184, 72.2 parts by weight of isopropyl alcohol and 13.8 parts by weight of methyl isobutyl ketone as a photopolymerization initiator were prepared.

The obtained coating liquid for forming the low refractive index layer is applied onto the hard coat layer (12) to form a coating film, and then dried in an oven at a temperature of 60 ° C. After drying, an ultraviolet irradiation device ( Using a Fusion UV System Japan, light source H bulb), an ultraviolet ray was irradiated at an irradiation dose of 384 mJ / m ² and cured to form a low refractive index layer (13) to produce an antireflection film (10).

(Example 2)
In (Example 1), an antireflection film (as in Example 1) except that the organically modified polysiloxane, which is a leveling agent for forming the low refractive index layer (13), was changed to 2.0 parts by weight. 10) was produced.

(Comparative Example 1)
As in Example 1, a triacetyl cellulose film having a thickness of 80 μm was prepared as the first transparent substrate (11).

The hard coat layer (12) formed on the surface of the first transparent substrate (11) is made by Nippon Synthetic Chemical Co., Ltd. as a ionizing radiation curable material, 100 parts by weight of purple light, UV-7605B, a photopolymerization initiator. As a mixture, 4 parts by weight of Ciba Japan Co., Ltd. Irgacure 184, 50 parts by weight of methyl acetate as a solvent and 50 parts by weight of 2-butanone were mixed to prepare a coating solution for forming a hard coat layer (12). A coating liquid for forming a hard coat layer is applied onto a triacetyl cellulose film as a transparent substrate (11), and then dried, and an irradiation dose of 300 mJ / m ² using an ultraviolet irradiation device (Fusion UV System Japan, light source H bulb). A transparent hard coat layer (12) having a dry film thickness of 10 μm was formed by irradiating with UV.

  Furthermore, the coating liquid for forming the low refractive index layer (13) formed on the surface of the hard coat layer (12) includes 36 parts by weight of low refractive index silica particles (average particle diameter: 50 nm), ionizing radiation curable type. 1.6 parts by weight of dipentaerythritol hexaacrylate (DPHA) as a material, 0.2 parts by weight of TSF44 manufactured by Toshiba GE Silicone as a silicone material having water repellency, Irgacure manufactured by Ciba Japan as a photopolymerization initiator 0.28 parts by weight of 184, 72.2 parts by weight of isopropyl alcohol as a solvent, and 13.8 parts by weight of methyl isobutyl ketone were prepared.

The obtained coating liquid for forming the low refractive index layer is applied onto the hard coat layer (12) to form a coating film, and then dried in an oven at a temperature of 60 ° C. After drying, an ultraviolet irradiation device ( Using a Fusion UV System Japan, light source H bulb), an ultraviolet ray was irradiated at an irradiation dose of 384 mJ / m ² and cured to form a low refractive index layer (13) to produce an antireflection film (10).

(Comparative Example 2)
In (Comparative Example 1), an antireflection film (10) is produced in the same manner as in (Comparative Example 1) except that the particle size of the low refractive index silica particles when forming the low refractive index layer (13) is changed to 80 nm. did.

(Comparative Example 3)
As in Example 1, a triacetyl cellulose film having a thickness of 80 μm was prepared as the first transparent substrate (11).

The hard coat layer (12) formed on the surface of the first transparent substrate (11) is made by Nippon Synthetic Chemical Co., Ltd. as a ionizing radiation curable material, 100 parts by weight of purple light, UV-7605B, a photopolymerization initiator. 4 parts by weight of Irgacure 184 manufactured by Ciba Geigy Co., 50 parts by weight of methyl acetate as a solvent and 50 parts by weight of 2-butanone were mixed to prepare a coating solution for forming the hard coat layer (12). A coating liquid for forming a hard coat layer (12) is applied onto a triacetyl cellulose film which is a transparent substrate (11), dried, and an irradiation dose of 300 mJ using an ultraviolet irradiation device (Fusion UV System Japan, light source H bulb). A transparent hard coat layer (12) having a dry film thickness of 10 μm was formed by irradiating with ultraviolet rays at / m ² .

  Furthermore, in the coating liquid for forming the low refractive index layer (13) formed on the surface of the hard coat layer (12), 0.2 parts by weight of an organically modified polysiloxane as a leveling agent and low refractive index silica particles ( 36 parts by weight of an average particle size of 80 nm), 1.6 parts by weight of dipentaerythritol hexaacrylate (DPHA) as an ionizing radiation curable material, and 0.2% of TSF44 manufactured by Toshiba GE Silicone as a silicone material having water repellency. 0.2 parts by weight of Ciba Japan Co., Ltd. Irgacure 184, 72.2 parts by weight of isopropyl alcohol and 13.8 parts by weight of methyl isobutyl ketone as a photopolymerization initiator were prepared.

The obtained coating liquid for forming the low refractive index layer is applied onto the hard coat layer (12) to form a coating film, and then dried in an oven at a temperature of 60 ° C. After drying, an ultraviolet irradiation device ( Using a Fusion UV System Japan, light source H bulb), an ultraviolet ray was irradiated at an irradiation dose of 384 mJ / m ² and cured to form a low refractive index layer (13) to produce an antireflection film (10).

(Comparative Example 4)
In (Comparative Example 3), an antireflection film (as in Comparative Example 3) except that the organically modified polysiloxane, which is a leveling agent for forming the low refractive index layer (13), was changed to 3.0 parts by weight. 10) was produced.

(Evaluation)
The antireflection film (10) obtained in (Example 1), (Example 2), and (Comparative Example 1) to (Comparative Example 4) was evaluated by the following method. The evaluation results are shown in (Table 1).

(surface tension)
Using a fully automatic surface tension meter (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.), the evaluation coating solution was taken on a petri dish by the Wilhelmy method, and the plate was once brought into contact with the evaluation coating solution and then measured again.

(Black tightening)
The surface of the low refractive index layer of the obtained antireflection film was irradiated with a three-wavelength fluorescent lamp and visually evaluated in reflected light. In the evaluation, a matte black paint was applied to the surface of the triacetylcellulose film, which is a transparent substrate, on which the low refractive index layer was not formed, and antireflection treatment was performed.
Black tightening refers to the degree to which black appears to be black. When the black tightening is weak, black appears to be blurred.

  In the visual evaluation, the determination method is “◯” when there is no white blur, “Δ” when there is a slight white blur, and “X” when there is white blur.

(Surface roughness)
Using a scanning probe microscope (Dimension D3100, manufactured by Nippon Beco Co., Ltd.), measurement was performed in a scanning range of 1 μm square.

(Average luminous reflectance)
About the surface of the low refractive index layer of the obtained antireflection film, the spectral reflectance at an incident angle of 5 ° was measured using an automatic spectrophotometer (manufactured by Hitachi, U-4100, measurement wavelength 360 to 800 nm). Further, the average luminous reflectance was obtained from the obtained spectral reflectance curve. In the measurement, a matte black paint was applied to the surface of the triacetylcellulose film, which is a transparent substrate, on which the low refractive index layer was not formed, and an antireflection treatment was performed.

  As shown in (Table 1), in (Comparative Example 1), although the black tightening is good, the average luminous reflectance is high. In (Comparative Example 2), white blurring occurred in the appearance and black tightening was bad. In (Comparative Example 3), white blurring in appearance slightly occurred, black tightening was poor, and the amount of change in surface roughness was small. In (Comparative Example 4), the leveling agent has bleed on the surface of the low refractive index layer in appearance. On the other hand, in (Example 1) and (Example 2), it can be seen that the average luminous reflectance is low and the black tightening is good.

The antireflection film of the present invention is used for the surfaces of image display devices, windows made of glass or plastic films, optical lenses, glasses and the like.

DESCRIPTION OF SYMBOLS 10 Antireflection film 11 1st transparent base material 12 Hard coat layer 13 Low refractive index layer 20 1st polarizing plate 22 2nd transparent base material 23 1st polarizing layer 200 Antireflection polarizing plate 210 Antireflection polarizing light Plate 30 Liquid crystal cell 40 Second polarizing plate 41 Third transparent substrate 42 Fourth transparent substrate 43 Second polarizing layer 50 Backlight unit

Claims (5)

  In an antireflection film in which a low refractive index layer is laminated on at least one surface of a transparent substrate, an ionizing radiation curable material, an organically modified polysiloxane as a leveling agent, and low refractive index silica particles having voids at least inside the particles An antireflection film formed by using a low refractive index coating agent comprising The addition amount of the organically modified polysiloxane is 0.5 parts by weight or more and 2.5 parts by weight or less,
Before and after the addition of the organically modified polysiloxane, the surface tension change is 2.0 mN / m or more and 6.0 mN / m or less, and the surface roughness change is 0.8 nm or more and 2.2 nm or less. Item 2. The antireflection film according to Item 1.   The antireflection film has a surface roughness (Ra) of 0.3 nm to 1.5 nm and an average luminous reflectance of 0.4% to 0.8%. Item 2. The antireflection film according to Item 1.   An antireflective polarizing plate comprising the antireflective film according to any one of claims 1 to 3 and a first polarizing plate on a surface where the low refractive index layer is not formed.   The antireflective polarizing plate according to claim 4, the liquid crystal cell, the second polarizing plate, and the backlight unit are provided in this order from the observer side, and the low refractive index layer non-formation surface of the antireflective polarizing plate A transmissive liquid crystal display characterized in that a liquid crystal cell is held on the side.

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