JP2013104959A - Antireflection film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an antireflection film having an excellent optical characteristics, which can provide a multilayer construction in one coating process.SOLUTION: An antireflection film comprises: a transparent base material; a hard coat layer which is laminated on the transparent base material; and an antireflection layer which is laminated on the hard coat layer. The hard coat layer is a mixed layer in which components of the transparent base material and a binder matrix are mixed. The antireflection layer includes, in an order from the hard coat layer side, a high refractive index layer in which the binder matrix is locally present and a low refractive index layer in which low refractive index particles are locally present, with the refractive index of the high refractive index layer being in the range of 1.51-1.58, the refractive index of the low refractive index layer being in the range of 1.29-1.43, and the optical film thickness of the low refractive index layer is in the range of 110 nm to 140 nm.

Description

  The present invention relates to an antireflection film, a polarizing plate using the antireflection film, a display device using the antireflection film, and a method for producing an antireflection film suitable for producing the antireflection film.

  In general, the image display apparatus has a problem that it becomes difficult to recognize an image when external light is reflected on a display screen. In recent years, opportunities to be taken not only indoors but also outdoors have increased, and reflection of external light on the display screen and high durability have become more important issues. Therefore, it has been proposed that a laminate in which layers having different refractive indexes are laminated as an antireflection layer is used as an antireflection film, and the antireflection film is provided on the display device surface.

  Further, in the antireflection film, in order to impart surface hardness and scratch resistance, a hard cord layer having excellent hardness is disposed inside the laminate.

  Further, it has been proposed to provide a polarizing layer on an antireflection film and use it as a polarizing plate for use in a display device or the like.

  For example, as a polarizing plate used for a liquid crystal display panel (LCD panel), a polarizing plate having a configuration in which a polarizing layer is provided on an antireflection film is known (see Patent Document 1).

  As a method for producing the antireflection film as described above, it has been proposed to use a wet film formation method. The wet film forming method is a method of forming a laminated body by adjusting a coating liquid for each layer and coating the coating liquid for each layer.

  For example, it is known that an antireflection film in which an antireflection layer / hard coat layer / transparent substrate is laminated in this order as viewed from the observation surface is manufactured using a wet film formation method (see Patent Document 2). ).

JP 2000-32428 A JP 2005-199707 A

  In the antireflection film, optical characteristics such as antireflection performance and other characteristics can be improved by adopting a multilayer structure. However, when manufacturing an antireflection film having a hard coat layer using a wet film formation method, the coating liquid in which materials are dispersed is adjusted for each layer, such as a hard coat layer and an antireflection layer, and the coating liquid is applied. There was a need to do. For this reason, there existed a problem that the number of manufacturing processes increased and manufacturing efficiency fell.

  Then, this invention was made | formed in order to solve the above-mentioned problem, and it is aimed at providing the manufacturing method of the anti-reflective film which can be set as a multilayer structure by one coating and is excellent in an optical characteristic. And

In order to solve the above problems, the invention according to claim 1 includes a transparent substrate, a hard coat layer laminated on the transparent substrate, and an antireflection layer laminated on the hard coat layer. The hard coat layer is a mixed layer in which the components of the transparent substrate and the binder matrix are mixed, and the antireflection layer is a high refractive index layer in which the binder matrix is localized in order from the hard coat layer side. And a low refractive index layer in which low refractive index particles are localized, the refractive index of the high refractive index layer is in the range of 1.51 to 1.58, and the refractive index of the low refractive index layer Is in the range of 1.29 to 1.43, and the optical film thickness of the low refractive index layer is in the range of 110 nm to 140 nm.
The invention according to claim 2 is characterized in that the mixed layer, the high refractive index layer, and the low refractive index layer are optically separated from each other. It was.
According to a third aspect of the present invention, the content of the low refractive index particles in the antireflection layer is 0.5 wt% or more and less than 5.0 wt%, and the content per unit area in the antireflection layer is low. the content of the refractive index particles were the antireflection film according to claim 1 or claim 2, characterized in that in the range of 0.05 g / m ² or more 0.50 g / m ² or less.
The invention according to claim 4 is a polarizing plate characterized in that a polarizing layer is provided on the antireflection film according to any one of claims 1 to 3.
Moreover, as invention concerning Claim 5, it was set as the display apparatus provided with the antireflection film in any one of Claims 1 thru | or 4.

An invention according to claim 6 is an antireflection film comprising a transparent substrate, a hard coat layer laminated on the transparent substrate, and an antireflection layer laminated on the hard coat layer. A manufacturing method comprising: dissolving or dispersing at least a low refractive index particle and a binder matrix in a solvent to adjust a coating liquid containing a component that dissolves and swells the transparent substrate; and the coating liquid A coating step for coating on a transparent substrate; and a drying step for drying the coating liquid coated on the transparent substrate to form a coating film on the transparent substrate. A mixture layer in which the components of the transparent substrate and the binder matrix are mixed, and the antireflective layer includes a high refractive index layer and a low refractive index particle in which the binder matrix is localized in order from the hard coat layer side. Station The refractive index of the high refractive index layer is in the range of 1.51 to 1.58, and the refractive index of the low refractive index layer is 1.29 to 1.43. The antireflection film manufacturing method is characterized in that it is in the following range and the optical film thickness of the low refractive index layer is in the range of 110 nm to 140 nm.
In the invention according to claim 7, the proportion of the solvent in the coating liquid is in the range of 55 wt% to 85 wt%, and the proportion of the component that dissolves and swells the transparent substrate in the solvent is 30 wt%. The antireflection film manufacturing method according to claim 6, wherein the method falls within a range of not less than 90% and not more than 90 wt%.

  The antireflection film of the present invention comprises a low refractive index particle and a binder matrix, and is coated with a coating solution containing a component that dissolves and swells the transparent substrate. An antireflection film having a multilayer structure in which a base material / a mixed layer in which a transparent base material is dissolved / swelled / a high refractive index layer in which a binder matrix is localized / a low refractive index layer in which low refractive index particles are localized is laminated in this order. Can be formed. For this reason, it is possible to produce an antireflection film that has not only sufficient optical properties but also low production costs.

It is the schematic which shows an example of the antireflection film of this invention. It is the schematic which shows an example of the polarizing plate of this invention. It is the schematic which shows an example of the display apparatus of this invention.

  The method for producing an antireflection film of the present invention comprises applying a coating liquid containing a component containing low refractive index particles and a binder matrix and dissolving and swelling a transparent substrate to the transparent substrate in one application. Antireflection of multilayer structure in which transparent substrate / mixed layer with transparent substrate dissolved / swelled / high refractive index layer with localized binder matrix / low refractive index layer with localized low refractive index particles laminated in this order A film can be formed.

  In the method for producing an antireflection film of the present invention, a “coating liquid containing a component that dissolves and swells a transparent substrate” is applied onto the transparent substrate. At this time, the “component that dissolves and swells the transparent substrate” penetrates into the transparent substrate, and at the same time, the components of the binder matrix also penetrate into the transparent substrate side. Thereby, a mixed layer in which the components of the transparent substrate and the binder matrix are mixed with a gradient is formed. Further, the low refractive index particles dispersed in the coating liquid are bulky as compared with the dissolved / melted binder matrix, and therefore do not easily penetrate into the transparent substrate side. Therefore, the low refractive index particles are segregated to the observation surface side, and the mixed layer and the antireflection layer (low refractive index layer and high refractive index layer) are separated.

  In addition, in the antireflection film manufacturing method of the present invention, when applying the “coating liquid containing a component that dissolves and swells the transparent base material” onto the transparent base material, the transparent base is applied from the transparent base material side to the applied liquid side. The component of the material moves. For this reason, in the applied coating liquid, a flow due to mass transfer occurs from the transparent substrate side to the surface side. At this time, the low refractive index particles dispersed in the coating liquid diffuse and move along the flow due to mass transfer. Therefore, the low refractive index particles are segregated on the observation surface side, and a low refractive index layer in which the low refractive index particles are localized and a high refractive index layer in which the binder matrix is localized are formed.

  As described above, in the antireflection film manufacturing method of the present invention, a hard coat layer (mixed layer) and an antireflection layer (high refractive index layer and low refractive index layer) are suitably formed by forming a mixed layer. Can be separated. Therefore, a multilayer laminate that can be efficiently used as an antireflection film can be formed by a single coating. The mixed layer gradually changes from the refractive index of the transparent substrate to the refractive index of the binder matrix of the low refractive index hard coat layer because the components of the transparent substrate and the components of the binder matrix are mixed with a gradient. Therefore, it is possible to prevent the occurrence of interference fringes caused by the difference in refractive index between the hard coat layer and the transparent substrate interface. Moreover, since the interface between the transparent substrate and the mixed layer is unclear, peeling at the layer interface can be suppressed.

  Since the layer formation is performed as described above, the physical boundary of each layer of the transparent substrate / mixed layer / high refractive index layer / low refractive index layer is not clear, but each layer is “optically Are separated ". “Optically separated” means that the spectral reflectance in visible light (380 nm or more and 800 nm or less) is obtained at an incident angle of 5 ° from the low refractive index layer side of the antireflection film of the present invention. This indicates a state in which interference peaks caused by the mixed layer, the high refractive index layer, and the low refractive index layer can be confirmed when optical simulation is performed on the refractive index.

  Hereinafter, the antireflection film manufacturing method of the present invention will be described.

<Coating solution adjustment process>
First, a coating liquid containing a component that dissolves and swells a transparent substrate is prepared by dispersing low refractive index particles and a binder matrix in a solvent.

The low-refractive particles are made of a low-refractive material such as LiF, MgF ₂ , 3NaF · AlF ₃ (all having a refractive index of 1.4), or Na ₃ AlF ₆ (cryolite, having a refractive index of 1.33). Refractive index particles can be used. Moreover, the particle | grains which have a space | gap inside a particle | grain can be used suitably. In the case of particles having voids inside the particles, the voids can be made to have a refractive index of air (≈1), so that they can be low refractive index particles having a very low refractive index. Specifically, low refractive index silica particles having voids inside can be used. Moreover, since the particle | grains which have a space | gap have small specific gravity and can segregate to the surface side suitably when forming a mixed layer, they are preferable as a low refractive particle used for the antireflection film of this invention.

  The particle size of the low refractive index particles is preferably in the range of about 1 nm to 100 nm, and more preferably in the range of about 50 nm to 80 nm. When the particle size exceeds 100 nm, light is remarkably reflected by Rayleigh scattering, the antireflection layer is whitened, and the transparency of the antireflection film tends to be lowered. On the other hand, when the particle size is less than 1 nm, problems such as non-uniformity of particles in the antireflection layer due to aggregation of particles occur.

  The binder matrix forming material of the present invention includes an ionizing radiation curable material. As the ionizing radiation curable material, an acrylic material can be preferably used. Acrylic materials are synthesized from polyfunctional or polyfunctional (meth) acrylate compounds such as polyhydric alcohol acrylic acid or methacrylic acid ester, diisocyanate and polyhydric alcohol, and acrylic acid or methacrylic acid hydroxy ester. Such a polyfunctional urethane (meth) acrylate compound can be used. Besides these, as ionizing radiation curable materials, it is possible to use polyether resins having an acrylate functional group, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, etc. it can.

  In the present invention, “(meth) acrylate” refers to 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, ethoxylated phenylphenol acrylate, propylene oxide modified nonylphenol (meth) acrylate , Methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, Xylpropylene 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, tetra Fluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropropyl (meth) acrylate, oct And adamantane derivative mono (meth) acrylate such as adamantyl acrylate having monovalent mono (meth) acrylate derived from tafluoropropyl (meth) acrylate, 2-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, ethoxylated bisphenol A diacrylate, 1.54 ethoxylated bisphenol A dimethacrylate, 9,9-bis (4- (2-acryloyloxyethoxyphenyl) fluorene and the like.

  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-hydroxy. Ethyl isocyanurate tri (meth) acrylate, tri (meth) acrylate such as glycerin tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, etc. Trifunctional (meth) acrylate compounds, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol te Trifunctional or higher polyfunctionality such as la (meth) acrylate, dipentaerythritol penta (meth) acrylate, ditrimethylolpropane penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane hexa (meth) acrylate ( Examples thereof include a (meth) acrylate compound and a polyfunctional (meth) acrylate compound obtained by substituting a part of these (meth) acrylates with an alkyl group or ε-caprolactone.

  Polyfunctional urethane acrylate can also be used as the acrylic material. 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-306I, 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, etc. can be mentioned, but not limited thereto.

  Besides these, as ionizing radiation curable materials, it is possible to use polyether resins having an acrylate functional group, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, etc. it can.

  In the present invention, in order to form a high refractive index layer below the low refractive index layer in the uneven distribution layer, as the ionizing radiation curable material for forming the high refractive index layer, in addition to the (meth) acrylate group An acrylic material having an aromatic ring can be suitably used. An acrylic material having an aromatic ring in addition to a (meth) acrylate group is bulky and therefore does not penetrate into the hard coat layer (mixed layer), so that a high refractive index layer is efficiently formed on the hard coat layer (mixed layer). Can be formed. Furthermore, an acrylic material having an aromatic ring in addition to a (meth) acrylate group has a high refractive index. More preferably, an acrylic material having a (meth) acrylate group as a substituent of bisphenol A can be used. Specific examples include ethoxylated bisphenol A dimethacrylate, ethoxylated bisphenol A diacrylate, ethoxylated phenylphenol acrylate, and the like.

  The binder matrix forming material can also include a thermoplastic resin. By including the thermoplastic resin, it is possible to suppress the occurrence of warping of the antireflection film itself. Examples of the thermoplastic resin include cellulose derivatives such as acetylcellulose, nitrocellulose, acetylbutylcellulose, ethylcellulose, and methylcellulose, vinyl acetate and copolymers thereof, vinyl chloride and copolymers thereof, vinylidene chloride and copolymers thereof, and the like. Vinyl resins, acetal resins such as polyvinyl formal and polyvinyl butyral, acrylic resins and copolymers thereof, acrylic resins such as methacrylic resins and copolymers thereof, polystyrene resins, polyamide resins, linear polyester resins, polycarbonate resins, Etc.

  Any photopolymerization initiator may be used as long as it generates radicals when irradiated with ionizing radiation. For example, photoinitiators of acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones can be used. The addition amount of the photopolymerization initiator is preferably in the range of about 0.1 to 10 parts by weight, more preferably 1 to 7 parts by weight with respect to 100 parts by weight of the ionizing radiation curable material. It is preferable that the amount is about part or less.

  As the solvent, an appropriately known material capable of dispersing and dissolving the material used for the binder matrix may be used according to the material selected for the transparent substrate. The solvent may be a mixed solvent in which a plurality of materials are mixed. By using a mixed solvent, the ratio of “solvent that dissolves and swells the transparent substrate” and “solvent that does not dissolve and swell the transparent substrate” is adjusted to adjust the ratio of “solvent and swell the transparent substrate” in the coating liquid. The amount of the component to be adjusted can be adjusted, and the coating liquid capable of suitably forming the mixed layer can be adjusted.

  In the case of using a mixed solvent, the ratio of the “solvent that dissolves and swells the transparent substrate” in the total solvent is preferably in the range of about 30 wt% to 90 wt%, and preferably about 40 wt% to 80 wt%. Within the range, more preferably within the range of about 50 wt% or more and 70 wt% or less. By being in the range of about 30 wt% or more and 90 wt% or less, it is possible to suitably form a mixed layer and segregate low refractive particles to form a low refractive index layer. When the amount is less than 30 wt%, the transparent substrate cannot be sufficiently dissolved and swollen, and a mixed layer cannot be suitably formed. On the other hand, if it is larger than 90 wt%, the thickness of the mixed layer increases and the hardness of the antireflection film decreases, and the low refractive index particles of the uneven distribution layer aggregate to cause undesired haze.

  Further, the ratio of the solvent in the coating liquid is preferably in the range of 55 wt% to 85 wt%. By setting it within the above range, formation of a low refractive index layer by segregation of low refractive index particles in the coating film and formation of a mixed layer by dissolution and swelling of the transparent substrate can be suitably performed. If it is less than 55 wt%, the coating film may dry rapidly and segregation may not be performed sufficiently. Moreover, when it exceeds 85 wt%, it is necessary to lengthen a drying time, and it becomes unsuitable for mass production.

  The solvent contained in the coating liquid is preferably a volatile solvent having a high boiling point. Specifically, the boiling point is preferably 100 ° C. or higher, and more preferably 200 ° C. or higher. This is because a higher boiling point makes it easier to adjust the time of the drying step, which is an important factor for forming the mixed layer and the low refractive index layer.

  When a triacetyl cellulose film is used for the transparent substrate, examples of the “solvent for dissolving and swelling the transparent substrate” include dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, dioxane, dioxolane, trioxane, Ethers such as tetrahydrofuran, anisole and phenetole, and some ketones such as acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone, and ethyl formate, propyl formate, formic acid Esters such as n-pentyl, methyl acetate, ethyl acetate, methyl propionate, propion brewed ethyl, n-pentyl acetate, and γ-ptyrolactone, Bed, cellosolve, butyl cellosolve, cellosolve such as cellosolve acetate, other N- methyl-2-pyrrolidone (N- methylpyrrolidone), dimethyl carbonate, and the like. Moreover, you may use the said solvent individually by 1 type or in combination of 2 or more types.

  When a triacetyl cellulose film is used as a transparent substrate, examples of the “solvent that does not dissolve or swell the transparent substrate” include, for example, alcohols such as ethanol and isopropyl alcohol, and aromatic carbonization such as toluene, xylene, cyclohexane, and cyclohexylbenzene. Examples thereof include hydrogens, hydrocarbons such as n-hexane, and some ketones such as methyl isobutyl ketone, methyl butyl ketone, and diacetone alcohol. Moreover, you may use the said solvent individually by 1 type or in combination of 2 or more types.

  Moreover, when using a triacetylcellulose film for a transparent base material, it is preferable that a solvent contains N-methylpyrrolidone. N-methylpyrrolidone has a high boiling point and good compatibility between triacetylcellulose and N-methylpyrrolidone, and can suitably form a mixed layer and a low refractive index layer.

  Moreover, you may add an additive to a coating liquid. For example, surface additives, refractive index adjusters, adhesion improvers, curing agents, and the like may be used as additives.

<Application process>
Next, the said coating liquid is apply | coated on a transparent base material.

  The material used for the transparent substrate may be appropriately selected from known materials in consideration of optical properties such as transparency and refractive index of light, and various physical properties such as impact resistance, heat resistance and durability. For example, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polyethylene naphthalate, celluloses such as triacetyl cellulose, diacetyl cellulose and cellophane, polyamides such as 6-nylon and 6,6-nylon, polymethyl Those made of an organic polymer such as acrylic, such as methacrylate, polystyrene, polyvinyl chloride, polyimide, polyvinyl alcohol, polycarbonate, ethylene vinyl alcohol are used. In particular, an organic polymer film such as polyethylene terephthalate, triacetyl cellulose, polycarbonate, polymethyl methacrylate, or the like may be used. The material used for the transparent substrate may be a material to which an additive is added. Examples of the additive include an ultraviolet absorber, an infrared absorber, a plasticizer, a lubricant, a colorant, an antioxidant, a flame retardant, and the like. The material used for the transparent substrate is particularly preferably a triacetyl cellulose film. A triacetyl cellulose film is a film having a small birefringence and good transparency. For this reason, it can be used suitably especially as an antireflection film provided on the surface of a liquid crystal display. The material used for the transparent substrate may be a mixture of one or more materials or a polymer.

  The thickness of the transparent substrate is preferably in the range of about 25 μm to 200 μm, and more preferably in the range of about 40 μm to 80 μm. However, the thickness of the transparent substrate used in the method for producing an antireflection film of the present invention is not limited to the above range. The transparent substrate may be a multilayer substrate in which a plurality of layers are laminated.

  As the coating method, a coating method using a roll coater, reverse roll coater, gravure coater, micro gravure coater, knife coater, bar coater, wire bar coater, die coater, dip coater, or the like can be used.

<Drying process>
Next, the said coating liquid apply | coated on the said transparent base material is dried, the solvent in a coating liquid is removed, and a coating film is formed on a transparent base material. Drying may be performed appropriately using a known drying means. For example, heating, blowing, hot air, etc. can be used as the drying means.

  Moreover, it is preferable that a drying process performs multiple steps of drying. In the antireflection film manufacturing method of the present invention, the mixed layer is formed by dissolving and swelling the transparent base material with the coating liquid. Therefore, if the drying is performed immediately after the coating liquid is applied, the formation of the mixed layer is inhibited. The For this reason, it can dry suitably, forming a mixed layer by performing drying of several steps and changing drying conditions for every step.

  For example, secondary drying may be performed after primary drying. At this time, the primary drying is preferably performed within a range of a drying temperature of about 20 ° C. to 30 ° C., and the secondary drying is preferably performed within a range of a drying temperature of about 50 ° C. to about 150 ° C.

  In the drying step, it is preferable that the time until the solvent contained in the coating film on the transparent substrate becomes 10 wt% or less is in the range of about 2 seconds to 60 seconds. In the initial stage of drying that “the solvent contained in the coating film is 10 wt% or less”, by setting the drying time within the above range, the formation of the mixed layer and the antireflection layer (low refractive index layer and high refractive index layer) Can be suitably performed. When the drying time is less than 2 seconds, segregation of the antireflection layer is inhibited by rapid drying of the coating liquid. Moreover, when the drying time is longer than 60 seconds, the tact time for production increases, which causes an increase in cost. In particular, when the antireflection film production method of the present invention is carried out by a roll-to-roll method, if the drying time is long, (1) the transport speed of the transparent substrate is reduced, and (2) the coating film is dried. It is necessary to lengthen the drying unit. For this reason, if the drying time is longer than 60 seconds, it is difficult to produce continuously, which is not realistic. In addition, the quantity of the solvent contained in the apply | coated coating liquid can be calculated | required by measuring a weight. It can also be measured by an infrared monitor.

  The drying step is preferably performed in a solvent atmosphere having a solvent concentration of 0.2 vol% or more and 10 vol% or less. Here, “solvent concentration” refers to the concentration of at least one solvent selected from the solvents contained in the coating liquid. When the solvent concentration is lower than 0.2 vol%, the drying becomes rapid and segregation of the antireflection layer is hindered. In addition, when the solvent concentration is higher than 10 vol%, the drying time increases and the tact time for production increases, which increases the cost.

<Ionizing radiation irradiation process>
Next, the coating film is cured by irradiating the coating film with ionizing radiation. Irradiate with ionizing radiation to cure. A high surface hardness can be imparted to the surface of the antireflection film, and an antireflection film having excellent scratch resistance can be obtained.

  As the ionizing radiation, ultraviolet rays, electron beams, or the like may be used. In the case of ultraviolet curing, a light source such as a high pressure mercury lamp, a low pressure mercury lamp, an ultra high pressure mercury lamp, a metal halide lamp, a carbon arc, or a xenon arc can be used. In the case of electron beam curing, electron beams emitted from various electron beam accelerators such as cockloftwald type, bandegraph type, resonant transformer type, insulated core transformer type, linear type, dynamitron type, and high frequency type are used. it can. The electron beam used preferably has an energy of about 50 KeV or more and 1000 KeV or less, and more preferably an electron beam having an energy of about 100 KeV or more and 300 KeV or less.

  The antireflection film manufacturing method of the present invention includes (1) a single-wafer method applied to a sheet-like transparent substrate, and (2) a roll-shaped transparent substrate applied, and the manufactured antireflection film is wound up. , Roll-to-roll method may be used. In particular, the roll-to-roll method can form an antireflection film continuously, and is preferable as an implementation method of the method for producing an antireflection film of the present invention. For example, when the anti-reflection film manufacturing method of the present invention is carried out using a roll-to-roll method, the transparent substrate is taken up in the following order: unwinding unit / coating unit / drying unit / ionizing radiation irradiation unit / winding unit. The antireflection film may be produced continuously by passing the film at a distance and continuously running.

  From the above, antireflection with laminated transparent substrate / mixed layer of transparent substrate dissolved / swelled / high refractive index layer with localized binder matrix and low refractive index layer with localized low refractive index particles / stacked in this order A film can be manufactured.

Hereinafter, the antireflection film of the present invention will be described.
The antireflection film of the present invention comprises a transparent substrate, a hard coat layer laminated on the transparent substrate, and an antireflection layer laminated on the hard coat layer,
The hard coat layer is a mixed layer in which the components of the transparent base material and a binder matrix are mixed, and the antireflection layer includes at least a low refractive index layer in which low refractive index particles are localized and a binder matrix. A high refractive index layer.

In the antireflection film of the present invention, the binder matrix is contained in each of the mixed layer / high refractive index layer / low refractive index layer, and is particularly localized in the high refractive index layer.
The abundance of the binder matrix in each layer constituting the antireflection film of the present invention can be determined by fluorescent X-ray analysis and Raman spectroscopic analysis. Moreover, the abundance (content ratio) of the low refractive index particles in each layer can be measured by fluorescent X-ray analysis. Further, the abundance (content ratio) of the transparent substrate component in each layer can be obtained by measuring a cross-sectional profile by Raman spectroscopic analysis. Moreover, the abundance (content) of the binder matrix in each layer can be determined by subtracting the abundance of the low refractive index particles and the transparent base material component in each layer from the whole. In addition, unless otherwise indicated, the density | concentration of the component of each layer described in this specification points out the density | concentration of the average component in each whole layer. In particular, the composition of the mixed layer changes with a gradient, so even if it is the concentration, the composition changes depending on the measurement part and is not fixed.

  In the mixed layer, the component of the transparent substrate and the component of the binder matrix are mixed, and the physical boundary between the transparent substrate and the mixed layer is not clear. For this reason, compared with the conventional antireflection film manufactured by coating each layer, (1) interference fringes generated by light interference at the layer interface and (2) physical peeling at the layer interface are suppressed. I can do it. In the antireflection film of the present invention, the mixed layer and the transparent substrate are not optically separated. In the present specification, “not optically separated” means that the spectral reflectance in visible light (380 nm or more and 800 nm or less) is obtained at an incident angle of 5 ° from the surface of the antireflection film. When an optical simulation is performed on the rate, it means a state in which the spectrum caused by the mixed layer cannot be observed.

  In the antireflection film of the present invention, the mixed layer and the antireflection layer are optically separated. According to the antireflection film manufacturing method of the present invention, layer separation between the mixed layer and the low refractive index layer can be promoted by forming the mixed layer. For this reason, when the optical measurement is performed, the mixed layer and the antireflection layer can be separated so as to be optically separated. In addition, although it repeats, in this specification, "optically isolate | separates" calculates | requires the spectral reflectance in visible light (380 nm or more and 800 nm or less) with the incident angle of 5 degrees from the surface of an antireflection film. In addition, it means a state where a spectral spectrum caused by each layer can be observed when an optical simulation is performed on this spectral reflectance.

  The high refractive index layer is a layer in which the binder matrix is localized. The high refractive index layer preferably contains a binder matrix of 95 vol% or more and 100 vol% or less. When the binder matrix contained in the high refractive index layer is less than 95 vol%, the transparent base material may be excessively dissolved or swollen by the coating liquid, and the binder matrix is diluted with the components derived from the transparent base material. There is a possibility that the required hard coat performance cannot be exhibited.

  In addition, the antireflection film of the present invention is “the refractive index of the low refractive index layer is in the range of 1.29 or more and 1.43 or less, and the optical film thickness of the low refractive index layer is 110 nm or more and 140 nm or less. The refractive index of the high refractive index layer is in the range of 1.51 to 1.58 ”. By setting the optical film thickness of the low refractive index layer within the range of about 110 nm to 140 nm, the optical film thickness of the low refractive index layer can be set to about ¼ wavelength of the visible light wavelength. Therefore, by forming the low refractive index layer and the high refractive index layer within the above range, an antireflection layer having high antireflection performance over a wide wavelength range can be obtained.

  When the optical film thickness of the low refractive index layer is within the above range, the spectral reflectance curve obtained from the observation surface side of the antireflection film can be a spectral reflectance curve having a minimum value in the vicinity of 500 nm. By making the spectral reflectance curve a spectral reflectance curve that takes a minimum value in the vicinity of 500 nm, a steep increase in the short wavelength direction when the minimum value of the spectral reflectance curve in the visible light wavelength range is used as a reference. Since it can suppress, it can be set as an antireflection film with small reflection hue and few color unevenness generation. The spectral reflectance curve of the antireflection film having the mixed layer that is not optically separated and the antireflection layer that is optically separated according to the present invention has a rising curve in the short wavelength direction based on the minimum value. It shows a steep tendency compared to the rising curve in the long wavelength direction. At this time, the steep rising curve in the short wavelength direction based on the minimum value of the spectral reflectance curve causes the color of the reflected light of the antireflection film, and uneven thickness of the uneven distribution layer. When it occurs, it may cause color unevenness of the antireflection film.

  In the present specification, “color unevenness” means reflected color unevenness due to film thickness unevenness of the antireflection layer, and refers to a phenomenon in which appearance defects occur when in-plane color variation increases. In addition, “interference fringes” are a type of color unevenness due to optical interference, mainly due to the difference in refractive index at the boundary between the transparent substrate and the dry film thickness, and multiple optical interferences occur simultaneously, resulting in a rainbow-like shape. A phenomenon in which uneven color is observed.

  Moreover, it is preferable that the content rate of the said low refractive index particle | grain in the said antireflection layer is 0.5 wt% or more and less than 5.0 wt%. Since the antireflective film of the present invention forms a low refractive index layer by segregation, it can exhibit sufficient antireflective performance with a small content as compared to the conventional amount, and has a low refractive index. A decrease in mechanical strength of the antireflection film due to excessive addition of particles can be prevented. When the content of the low refractive index particles is less than 0.5 wt%, a sufficient amount of the low refractive index particles cannot be segregated, and there is a possibility that sufficient antireflection performance as an antireflection film cannot be obtained. is there. On the other hand, when the content of the low refractive index particles exceeds 5 wt%, the visible light transmittance of the obtained antireflection film is lowered, the mechanical strength is lowered, and the cost may be increased.

Further, it is preferable that the content of the low refractive index particles per unit area of the antireflection layer is in the range of 0.05 g / ^{m 2} or more 0.50 g / ^{m 2} or less. When the content of the low refractive index particles is less than 0.05 g / m ² , a sufficient amount of the low refractive index particles cannot be segregated, and sufficient antireflection performance as an antireflection film cannot be obtained. There is a fear. Further, when the content of the low refractive index particles per unit area exceeds 0.5 g / m ² , the visible light transmittance of the obtained antireflection film is lowered, the mechanical strength is lowered, and the cost may be increased. is there.

  In addition, the total film thickness of the three layers of the hard coat layer and antireflection layer (high refractive index layer and low refractive index layer) formed by one application is in the range of about 2.5 μm to 15 μm. Is preferred. When it is smaller than 2.5 μm, it is not preferable because sufficient hard coat properties are not provided and the hardness of the antireflection film becomes insufficient. On the other hand, if it is larger than 15 μm, from the viewpoint of (1) increase in cost due to increase in the amount of coating liquid used, (2) decrease in flexibility, (3) occurrence of curling of the antireflection film due to curing shrinkage of the coating film, etc. It is not preferable. However, the total film thickness of the head coat layer and the antireflection layer in the antireflection film of the present invention is not limited to the above range.

  In the antireflection film of the present invention, the visual average reflectance on the observation surface side is preferably in the range of about 0.3% to 2.0%, and more preferably 0.5% to 1.5%. More preferably within the following range. When the visual average reflectance on the surface of the antireflection film on the observation surface side is larger than 2.0%, an antireflection film having sufficient antireflection performance cannot be obtained. Moreover, when the visual average reflectance on the antireflection film surface on the observation surface side is smaller than 0.3%, it is difficult to function as an antireflection film due to optical interference.

FIG. 1 shows an example of the antireflection film 1 of the present invention.
FIG. 1 is a schematic cross-sectional view of an antireflection film 1 of the present invention comprising an antireflection layer 11 laminated on an upper layer of a transparent substrate 20 and comprising a mixed layer 12 which is a hard coat layer and an upper layer of the mixed layer 12. is there. In FIG. 1, the antireflection layer 11 is composed of two layers: a high refractive index layer 11b in which a binder matrix is localized, and a low refractive index layer 11a in which low refractive index particles are localized on the upper layer of the high refractive index layer 11b. .

Hereinafter, the polarizing plate of the present invention will be described.
The polarizing plate of the present invention is a polarizing plate characterized in that a polarizing layer is provided on the antireflection film described above.

  The polarizing layer may be formed by appropriately selecting a material that exhibits physical properties to be polarized when transmitted from known materials. For example, a PVA polarizing film may be used. A PVA polarizing film is a film that exhibits polarizing performance by orienting and adsorbing iodine to a stretched and oriented polyvinyl alcohol film and derivatives thereof.

FIG. 2 shows an example of the polarizing plate of the present invention.
FIG. 2 is a schematic cross-sectional view of the polarizing plate 2 of the present invention having a configuration in which the polarizing layer 22 is held between the transparent substrate side of the antireflection film 1 of the present invention and the polarizing plate transparent substrate 1. The polarizing plate transparent substrate 1 may be appropriately selected from the same materials as the transparent substrate that can be used in the antireflection film 1 of the present invention. For example, a film made of triacetyl cellulose may be used as the polarizing plate transparent substrate 1.

The display device of the present invention will be described below.
The display device of the present invention is a display device provided with the antireflection film described above.
Examples of the display device of the present invention include a display device in which the antireflection film of the present invention is attached to the observation surface side, and a display device in which the polarizing plate of the present invention described above is incorporated.

  The display device of the present invention may include other functional members in addition to the antireflection film and the polarizing plate of the present invention. Other functional members include, for example, a diffusion film, a prism sheet, a brightness enhancement film, a retardation film for compensating for a retardation of a liquid crystal cell and a polarizing plate, for effectively using light emitted from a backlight, Etc.

FIG. 3 shows a transmissive liquid crystal display in which the polarizing plate of the present invention is incorporated as an example of the display device of the present invention.
FIG. 3 is a schematic cross-sectional view of a display device in which polarizing plate 2 / liquid crystal cell 3 / second polarizing plate 4 / backlight unit 5 are arranged in this order as viewed from the observation surface side. The polarizing plate 2 has a configuration in which the polarizing layer 22 is held between the transparent base material side of the antireflection film 1 of the present invention and the polarizing plate transparent base material 21. The second polarizing plate has a configuration in which the second polarizing plate polarizing layer 42 is held between the second polarizing plate transparent base material upper layer 40 and the second polarizing plate transparent base material lower layer 41. Further, the backlight unit 5 projects light toward the viewing surface direction. The light projected from the backlight unit 5 passes through the second polarizing plate 4 / liquid crystal cell 3 / polarizing plate 2 in order, and displays a pattern on the observation surface.

<Example 1>
First, the coating liquid containing the component which melt | dissolves and swells a transparent base material was adjusted. The composition is shown below.

(Coating liquid: Example 1)
Low refractive particles: Hollow silica fine particle dispersion (primary particle diameter 30 nm / solid content 20 wt% / isopropyl alcohol dispersion) 6.0 parts by weight.
Binder matrix (ionizing radiation curable material): 23.3 parts by weight of pentaerythritol tetraacrylate (PETA), 15.6 parts by weight of ethoxylated bisphenol A dimethacrylate (manufactured by Shin-Nakamura Chemical).
Photopolymerization initiator: 2.0 parts by weight of Irgacure 184 (manufactured by Ciba Japan).
Solvent: methyl ethyl ketone: isopropyl alcohol: N-methylpyrrolidone = 55.2 parts by weight of a mixed solvent mixed at 6: 2: 2 (weight ratio).
Solid content: 40 wt%
Solvent content in the coating liquid: 60 wt%
Ingredient for dissolving / swelling transparent base material in solvent: 55 wt%

Next, the coating liquid was apply | coated on the transparent base material.
At this time, the transparent substrate was a triacetyl cellulose film (refractive index 1.49, thickness 80 μm). Moreover, it apply | coated using the wire bar coater.

Next, the applied coating liquid was dried to form a coating film on the transparent substrate.
At this time, primary drying, secondary drying, and two-stage drying were performed. The drying conditions of primary drying and secondary drying are shown below.

(Drying conditions)
Primary drying: room temperature drying at 25 ° C. for 30 seconds in a semi-enclosed space under a solvent atmosphere of 2 vol% or more and 5 vol% or less.
Secondary drying: dried in an oven at 80 ° C. for 1 minute.
In the primary drying, the time required for the solvent contained in the coating film on the transparent substrate to be 10 wt% or less was 4 seconds.

Next, the coating film was irradiated with ionizing radiation to cure the coating film.
At this time, ultraviolet rays were irradiated as ionizing radiation. In addition, the irradiation of ultraviolet rays was carried out using a conveyor type ultraviolet curing device with an exposure amount of 400 mJ / cm 2.

  From the above, an antireflection film of the present invention in which a transparent substrate / mixed layer / high refractive index layer / low refractive index layer was laminated in this order was obtained.

<Example 2>
An antireflection film was produced in the same manner as in Example 1. However, the composition of the coating liquid was the following composition containing ethoxylated bisphenol A diacrylate in the binder matrix.

(Coating solution: Example 2)
Low refractive particles: Hollow silica fine particle dispersion (primary particle diameter 30 nm / solid content 20 wt% / isopropyl alcohol dispersion) 6.0 parts by weight.
Binder matrix (ionizing radiation curable material): 23.3 parts by weight of pentaerythritol tetraacrylate (PETA), 15.6 parts by weight of ethoxylated bisphenol A diacrylate (manufactured by Shin-Nakamura Chemical).
Photopolymerization initiator: 2.0 parts by weight of Irgacure 184 (manufactured by Ciba Japan).
Solvent: methyl ethyl ketone: diacetone alcohol: N-methylpyrrolidone = 55.2 parts by weight of a mixed solvent mixed at 5: 3: 2 (weight ratio).
Solid content: 40 wt%
Solvent content in the coating liquid: 60 wt%
Ingredient for dissolving / swelling transparent base material in solvent: 55 wt%

<Example 3>
An antireflection film was produced in the same manner as in Example 1. However, the composition of the coating liquid was the following composition using the binder matrix containing ethoxylated bisphenol A diacrylate and increasing the weight parts of the hollow particles.

(Coating liquid: Example 3)
Low refractive particles: Hollow silica fine particle dispersion (primary particle diameter 30 nm / solid content 20 wt% / isopropyl alcohol dispersion) 7.0 parts by weight.
Binder matrix (ionizing radiation curable material): 23.3 parts by weight of pentaerythritol tetraacrylate (PETA), 15.6 parts by weight of ethoxylated bisphenol A diacrylate (manufactured by Shin-Nakamura Chemical).
Photopolymerization initiator: 2.0 parts by weight of Irgacure 184 (manufactured by Ciba Japan).
Solvent: methyl ethyl ketone: isopropyl alcohol: diacetone alcohol = 55.2 parts by weight of a mixed solvent mixed at 6: 6: 2 (weight ratio).
Solid content: 40 wt%
Solvent content in the coating liquid: 60 wt%
Ingredient that dissolves and swells transparent base material in solvent: 64 wt%

<Example 4>
An antireflection film was produced in the same manner as in Example 1. However, the composition of the coating liquid was the following composition containing ethoxylated phenylphenol acrylate in the binder matrix.

(Coating solution: Example 4)
Low refractive particles: Hollow silica fine particle dispersion (primary particle diameter 30 nm / solid content 20 wt% / isopropyl alcohol dispersion) 6.0 parts by weight.
Binder matrix (ionizing radiation curable material): 26.1 parts by weight of pentaerythritol tetraacrylate (PETA), 14 parts by weight of ethoxylated phenylphenol acrylate (manufactured by Shin-Nakamura Chemical).
Photopolymerization initiator: 2.0 parts by weight of Irgacure 184 (manufactured by Ciba Japan).
Solvent: methyl ethyl ketone: isopropyl alcohol: N-methylpyrrolidone = 54 parts by weight of a mixed solvent mixed at 6: 6: 2 (weight ratio).
Solid content: 40 wt%
Solvent content in the coating liquid: 60 wt%
Ingredient for dissolving / swelling transparent base material in solvent: 55 wt%

<Comparative Example 1>
An antireflection film was produced in the same manner as in Example 1. However, the composition of the coating liquid was the following composition containing diethylene glycol di (meth) acrylate in the binder matrix.

(Coating liquid: Comparative Example 1)
Low refractive particles: Hollow silica fine particle dispersion (primary particle diameter 30 nm / solid content 20 wt% / isopropyl alcohol dispersion) 6.0 parts by weight.
Binder matrix (ionizing radiation curable material): 23.3 parts by weight of pentaerythritol tetraacrylate (PETA), 15.6 parts by weight of diethylene glycol di (meth) acrylate.
Photopolymerization initiator: 2.0 parts by weight of Irgacure 184 (manufactured by Ciba Japan).
Solvent: methyl ethyl ketone: isopropyl alcohol: N-methylpyrrolidone = 55.2 parts by weight of a mixed solvent mixed at 6: 6: 2 (weight ratio).
Solid content: 40 wt%
Solvent content in the coating liquid: 60 wt%
Ingredient for dissolving / swelling transparent base material in solvent: 55 wt%

<Comparative example 2>
An antireflection film was produced in the same manner as in Example 1. However, the composition of the coating liquid was as follows, including diethylene glycol di (meth) acrylate in the binder matrix and increasing the weight parts of the low refractive particles.

(Coating solution: Comparative example 2)
Low refractive particles: Hollow silica fine particle dispersion (primary particle size 30 nm / solid content 20 wt% / isopropyl alcohol dispersion) 9.0 parts by weight.
Binder matrix (ionizing radiation curable material): 22 parts by weight of pentaerythritol tetraacrylate (PETA), 15.1 parts by weight of diethylene glycol di (meth) acrylate.
Photopolymerization initiator: 2.0 parts by weight of Irgacure 184 (manufactured by Ciba Japan).
Solvent: methyl ethyl ketone: isopropyl alcohol: N-methylpyrrolidone = 54 parts by weight of a mixed solvent mixed at 6: 6: 2 (weight ratio).
Solid content: 40 wt%
Solvent content in the coating liquid: 75 wt%
Ingredient that dissolves and swells transparent base material in solvent: 28 wt%

<Comparative Example 3>
An antireflection film was produced in the same manner as in Example 1. However, the composition of the coating liquid was the following composition containing 9,9-bis (4- (2-acryloyloxyethoxyphenyl) fluorene in the binder matrix.

(Coating liquid: Comparative Example 3)
Low refractive particles: Hollow silica fine particle dispersion (primary particle diameter 30 nm / solid content 20 wt% / isopropyl alcohol dispersion) 6.0 parts by weight.
Binder matrix (ionizing radiation curable material): 23.3 parts by weight of pentaerythritol tetraacrylate (PETA), 15.6 parts by weight of 9,9-bis (4- (2-acryloyloxyethoxyphenyl) fluorene.
Photopolymerization initiator: 2.0 parts by weight of Irgacure 184 (manufactured by Ciba Japan).
Solvent: methyl ethyl ketone: isopropyl alcohol: N-methylpyrrolidone = 55.2 parts by weight of a mixed solvent mixed at 6: 6: 2 (weight ratio).
Solid content: 40 wt%
Solvent content in the coating liquid: 60 wt%
Ingredient for dissolving / swelling transparent base material in solvent: 55 wt%

<Comparative example 4>
An antireflection film was produced in the same manner as in Example 1. However, the composition of the coating liquid was the following composition in which the solvent was toluene, the component that did not dissolve and swell the transparent base material was included, and the mixed layer was not formed.

(Coating solution: Comparative example 4)
Low refractive particles: Hollow silica fine particle dispersion (primary particle diameter 30 nm / solid content 20 wt% / isopropyl alcohol dispersion) 6.0 parts by weight.
Binder matrix (ionizing radiation curable material): 23.3 parts by weight of pentaerythritol tetraacrylate (PETA), 15.6 parts by weight of ethoxylated bisphenol A dimethacrylate (manufactured by Shin-Nakamura Chemical).
Photopolymerization initiator: 2.0 parts by weight of Irgacure 184 (manufactured by Ciba Japan).
Solvent: 55.2 parts by weight of toluene.
Solid content: 40 wt%
Solvent content in the coating liquid: 60 wt%
Ingredient that dissolves and swells transparent substrate in solvent: 0 wt%

<Comparative Example 5>
The antireflection film in which the transparent substrate / hard coat layer / high refractive index layer / low refractive index layer were laminated in this order was laminated for each layer by a wet film forming method to produce an antireflection film.

First, a coating liquid for forming a hard coat layer was applied to a transparent substrate, dried, and irradiated with ultraviolet rays to form a hard coat layer on the transparent substrate. At this time, a triacetyl cellulose film was used as the transparent substrate. A wire bar coater was used for coating. Moreover, drying conditions were set to 80 degreeC drying for 1 minute in oven. Moreover, the ultraviolet-ray irradiation was made into the exposure amount of 400mJ / cm < ² > using the conveyor type | mold ultraviolet curing device. The formed hard coat layer had a thickness of 5 μm. The composition of the hard coat layer forming coating solution is shown below.

(Hardcoat layer forming coating solution: Comparative Example 5)
Ionizing radiation curable material: 10 parts by weight of dipentaerythritol hexaacrylate (DPHA), 30 parts by weight of pentaerythritol tetraacrylate (PETA), 10 parts by weight of urethane acrylate (UA-306T manufactured by Kyoeisha Chemical Co., Ltd.).
Photopolymerization initiator: Irgacure 184 (Ciba Japan Co., Ltd.) 2.5 parts by weight.
Solvent: 25 parts by weight of methyl ethyl ketone, 25 parts by weight of butyl acetate.

  Next, a coating solution for forming a high refractive index layer was applied on the surface-treated hard coat layer and dried to form a high refractive index layer on the hard coat layer. At this time, the surface treatment of the hard coat layer was an alkali treatment. A wire bar coater was used for coating. The drying conditions were oven-dried at 120 ° C. for 1 minute. Further, the optical film thickness (nd) of the formed high refractive index layer was set to ¼ of the visible light wavelength. Hereafter, the adjustment method of the coating liquid for high refractive index layer formation is shown.

(Coating liquid for forming a high refractive index layer: Comparative Example 5)
Isopropyl alcohol and 0.1N hydrochloric acid were added to tetraethoxysilane and hydrolyzed to obtain a solution containing a tetraethoxysilane polymer. Antimony-doped tin oxide (ATO) fine particles with a primary particle size of 8 nm are mixed in a solution containing a tetraethoxysilane polymer, isopropyl alcohol is added, and tetraethoxysilane is added to 100 parts by weight of the coating solution for forming a high refractive index layer. A coating solution for forming a high refractive index layer containing 2.5 parts by weight of the coalescence and 2.5 parts by weight of antimony-doped tin oxide fine particles was prepared.

  Next, a coating solution for forming a low refractive index layer was applied on the high refractive index layer and dried to form a low refractive index layer. At this time, a wire bar coater was used for coating. The drying conditions were oven-dried at 120 ° C. for 1 minute. Hereafter, the adjustment method of the coating liquid for low refractive index layer formation is shown.

(Low refractive index layer forming coating solution: Comparative Example 5)
Tetraethoxysilane and 1H, 1H, 2H, 2H-perfluorooctyltrimethoxysilane are mixed at a molar ratio of 95: 5 and hydrolyzed by adding isopropyl alcohol and 0.1N hydrochloric acid to form an organosilicon compound. A solution containing the polymer was obtained. A low refractive index silica fine particle dispersion (with a primary particle size of 30 nm / solid content of 20% by weight) having voids inside is mixed into a solution containing a polymer of an organosilicon compound, isopropyl alcohol is added, and a coating for forming a low refractive index layer is added. A coating solution for forming a low refractive index layer containing 2.0 parts by weight of an organosilicon compound and 2.0 parts by weight of low refractive index silica fine particles in 100 parts by weight of the liquid was obtained.

  From the above, an antireflection film was obtained in which a transparent substrate / hard coat layer / high refractive index layer / low refractive index layer were laminated in this order.

<Measurement / Evaluation>
About the obtained antireflection films of Examples 1 to 4 and Comparative Examples 1 to 5, (1) the content of low refractive index particles in the antireflection layer, the content of low refractive index particles per unit area of the antireflection layer, (2) Spectral reflectance measurement, (3) Luminous average reflectance measurement, (4) Presence / absence of mixed layer, (5) Steel wool resistance, (6) Interference fringe measurement were performed. Table 1 summarizes the results.

(1) The content of low refractive index particles in the antireflection layer and the content of low refractive index particles per unit area of the antireflection layer.
The amount (wt%) of low refractive index particles in the antireflection layer (low refractive index layer and high refractive index layer) was measured using fluorescent X-ray analysis. Further, the content (g / m ² ) of the low refractive index particles per unit area of the antireflection layer was obtained from the abundance (wt%) of the low refractive index particles and the thickness of the antireflection layer.

(2) Measurement of spectral reflectance.
About the antireflection film, the surface opposite to the observation surface was applied in black by a black matte spray, and the spectral reflectance on the observation surface side was measured using an automatic spectrophotometer (Hitachi, U-4000). At this time, the measurement conditions were a C light source, a 2-degree field of view, and an incident angle of 5 °. In addition, the optical simulation method is used to determine the presence or absence of the low refractive index layer and the high refractive index layer, the optical film thickness, the refractive index of the low refractive index layer, and the refractive index of the high refractive index layer from the obtained spectral reflectance curve. It was. Here, the optical film thickness (nd) is a value obtained by multiplying the refractive index (n) of the target layer by the layer thickness (d). Therefore, when the optical film thickness obtained by the optical simulation is thicker than the assumed film thickness, it can be determined that the low refractive index layer in which the low refractive particles are localized is formed.
In addition, when only the interference peak corresponding to the assumed film thickness of the dried coating film is observed from the spectral reflectance obtained from the antireflection film (a large number of ripples are observed in the waveform of the spectral spectrum), the binder matrix is further transparent. This means that there is no layer containing the substrate component, which indicates that there is no mixed layer.

(3) Measurement of luminous average reflectance.
About the antireflection film, the surface opposite to the observation surface was applied in black by a black matte spray, and the spectral reflectance on the observation surface side was measured using an automatic spectrophotometer (Hitachi, U-4000). At this time, the measurement conditions were a C light source, a 2-degree field of view, and an incident angle of 5 °. Further, the average luminous reflectance (Y%) was calculated from the obtained spectral reflectance. At this time, the standard visual acuity for photopic vision was used as the specific visual sensitivity.

(4) Presence or absence of mixed layer.
The antireflection film was cross-sectioned with a microtome, and the cross-section was observed using an electron microscope. At this time, the mixed layer was formed when the boundary with the transparent substrate was unclear. Moreover, when it was judged that the mixed layer was formed, it confirmed that the cross-sectional profile of the mixed layer was 0.5 micrometer or more.

(5) Resistance to steel wool.
The surface of the anti-reflection film is attached to steel wool (Bonster No. 0000 Nippon Steel Wool Co., Ltd.) on a Gakushin type friction fastness tester (AB301, manufactured by Tester Sangyo Co., Ltd.), and the surface is 10 under a load of 200 g. By rubbing repeatedly, the presence or absence of scratches on the surface was visually confirmed.

(6) Measurement of interference fringes.
About the antireflection film, a fluorescent lamp was reflected on the observation surface side, and the presence or absence of interference fringes was confirmed by visually observing the reflected light.

  From Table 1, it was confirmed that Examples 1-7 in which the mixed layer was formed formed a low refractive index layer in which low refractive index particles were localized. Therefore, it was confirmed that by forming the mixed layer, the low refractive index particles are localized, and a multi-layer laminate can be formed by a single coating to produce an antireflection film.

  In Example 1, a high refractive index layer in which ethoxylated bisphenol A dimetallate was localized was formed by using ethoxylated bisphenol A dimethacrylate in the binder matrix. The average luminous reflectance (%) was 0.46. Therefore, it was confirmed that it can be suitably used as an antireflection film.

  Moreover, in Example 2, the high refractive index layer in which the ethoxylated bisphenol A diacrylate was localized was formed by using ethoxylated bisphenol A diacrylate in the binder matrix. The average luminous reflectance (%) was 0.38. Therefore, it was confirmed that it can be suitably used as an antireflection film. In addition, it was confirmed that by using ethoxylated bisphenol A diacrylate, excellent antireflection performance can be provided even with low refractive particles of the same amount as in Example 1.

  In Example 3, the average luminous reflectance (%) was 0.33 by increasing the amount of low refractive particles compared to Example 2. Therefore, it was confirmed that it can be suitably used as an antireflection film.

  Moreover, in Example 4, the high refractive index layer in which the ethoxylated phenylphenol acrylate was localized was formed by using ethoxylated phenylphenol acrylate for the binder matrix. For this reason, the refractive index of the high refractive index layer can be improved, and the average luminous reflectance (%) was 0.27. Therefore, it was confirmed that it can be suitably used as an antireflection film. It was also confirmed that by using ethoxylated phenylphenol acrylate, even with the same amount of low refractive particles as in Example 1, excellent antireflection performance can be provided.

In Comparative Example 1, a high refractive index layer in which diethylene glycol di (meth) acrylate was localized was formed by using diethylene glycol di (meth) acrylate in the binder matrix, but the formed high refractive index layer was 1 It did not satisfy the range of not less than 51 and not more than 1.58, and could not be the antireflection film of the present invention. The antireflection film of Comparative Example 1 had a higher average luminous reflectance than the antireflection films of Examples 1 to 4, and was inferior in antireflection performance.

  In Comparative Example 2, a high refractive index layer in which diethylene glycol di (meth) acrylate was localized was formed by using diethylene glycol di (meth) acrylate in the binder matrix, but the formed high refractive index layer was 1 It did not satisfy the range of not less than 51 and not more than 1.58, and could not be the antireflection film of the present invention. Moreover, since the amount of the low refractive particles was increased as compared with Comparative Example 1, the average luminous reflectance (%) was lower than that of Comparative Example 1 in average luminous reflectance (%). However, the antireflection film of Comparative Example 2 had a higher average luminous reflectance than the antireflection films of Examples 1 to 4, and was inferior in antireflection performance. Moreover, it was confirmed that the steel wool resistance was reduced in Comparative Example 2 in which the composition in which the amount of the low refractive particles was increased was applied as a coating liquid and layer formation was performed.

  In Comparative Example 3, 9,9-bis (4- (2-acryloyloxyethoxyphenyl) fluorene was localized by using 9,9-bis (4- (2-acryloyloxyethoxyphenyl) fluorene. Although the high refractive index layer was formed, the formed high refractive index layer did not satisfy the range of 1.51 or more and 1.58 or less, and could not be used as the antireflection film of the present invention. The antireflection film 3 had an average luminous reflectance (%) of 0.13, but it was confirmed that interference fringes were generated because the refractive index of the high refractive index layer was too high.

  Moreover, in Comparative Example 4, the mixed layer was not formed because the coating liquid did not contain a component that dissolves and swells the transparent substrate. For this reason, low refractive particles did not segregate, and a sufficiently low refractive index layer was not formed. Moreover, since the mixed layer was not formed, the boundary between the dried coating film and the transparent substrate was clarified, and the occurrence of interference fringes due to the layer thickness between the dried coating film and the transparent substrate was confirmed. . Therefore, an antireflection film having sufficient antireflection performance could not be obtained.

  Further, in Comparative Example 5, since each layer was manufactured using the wet film forming method, the boundary between the layers was clarified, and the occurrence of interference fringes due to the difference in refractive index between the layers was confirmed. Therefore, an antireflection film having sufficient antireflection performance could not be obtained. Moreover, in the comparative example 2, it was necessary to adjust and apply | coat a coating liquid for every layer, and compared with Examples 1-4, there were many process steps to manufacture.

  The present invention is expected to be used as an antireflection film provided for the purpose of preventing external light from being reflected. Moreover, the use as a polarizing plate is anticipated by providing a polarizing layer in an antireflection film. For example, (1) liquid crystal display (LCD), transmissive liquid crystal display (LCD), CRT display, organic electroluminescence display (ELD), plasma display (PDP), surface electric field display (SED), field emission display (FED), It is expected to be used as an antireflection film and a polarizing plate used for display devices such as (2) window surfaces such as glass and plastic films, and (3) surfaces of optical members such as optical lenses and glasses.

DESCRIPTION OF SYMBOLS 1 ... Antireflection film 11 ... Antireflection layer 11a ... Low refractive index layer 11b ... High refractive index layer 12 ... Hard coat layer 20 ... Transparent base material 2 ... Polarizing plate 21 ... Polarizing plate transparent group Material 22 ... Polarizing layer 3 ... Liquid crystal cell 4 ... Second polarizing plate 40 ... Second polarizing plate transparent base material upper layer 41 ... Second polarizing plate transparent base material lower layer 42 ... Second polarizing plate polarizing layer 5 …… Backlight unit

Claims (7)

A transparent substrate;
A hard coat layer laminated on the transparent substrate;
An antireflection layer laminated on the hard coat layer,
The hard coat layer is a mixed layer in which the components of the transparent substrate and a binder matrix are mixed,
The antireflection layer has a high refractive index layer in which the binder matrix is localized and a low refractive index layer in which low refractive index particles are localized in order from the hard coat layer side,
The refractive index of the high refractive index layer is in the range of 1.51 to 1.58, and
The reflection characterized in that the refractive index of the low refractive index layer is in the range of 1.29 to 1.43 and the optical film thickness of the low refractive index layer is in the range of 110 nm to 140 nm. Prevention film. The antireflection film according to claim 1, wherein the mixed layer, the high refractive index layer, and the low refractive index layer are optically separated. The content of the low refractive index particles in the antireflection layer is 0.5 wt% or more and less than 5.0 wt%,
To claim 1 or claim 2, wherein the content of the low refractive index particles per unit area of the antireflection layer is in the range of 0.05 g / m ² or more 0.50 g / m ² or less The antireflection film as described. A polarizing plate provided with a polarizing layer on the antireflection film according to claim 1.   A display device comprising the antireflection film according to claim 1. An antireflection film comprising a transparent substrate, a hard coat layer laminated on the transparent substrate, and an antireflection layer laminated on the hard coat layer,
A coating liquid adjusting step of adjusting a coating liquid containing a component that dissolves or disperses at least the low refractive index particles and the binder matrix in a solvent and dissolves and swells the transparent substrate;
An application step of applying the coating liquid on a transparent substrate;
Drying the coating liquid applied on the transparent substrate, and forming a coating film on the transparent substrate, and
The hard coat layer is a mixed layer in which the components of the transparent substrate and the binder matrix are mixed,
The antireflection layer has a high refractive index layer in which the binder matrix is localized and a low refractive index layer in which low refractive index particles are localized in order from the hard coat layer side,
The refractive index of the high refractive index layer is in the range of 1.51 to 1.58, and
Reflection characterized in that the refractive index of the low refractive index layer is in the range of 1.29 to 1.43 and the optical film thickness of the low refractive index layer is in the range of 110 nm to 140 nm. Prevention film manufacturing method. The proportion of the solvent in the coating liquid is in the range of 55 wt% to 85 wt%,
The method for producing an antireflection film according to claim 6, wherein the proportion of the component that dissolves and swells the transparent substrate in the solvent is in the range of 30 wt% to 90 wt%.

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