JP2013064832A - Manufacturing method of antireflection film and antireflection film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antireflection film which is excellent in optical performance and is produced by using a safe and inexpensive material.SOLUTION: An antireflection film 1 includes a low refractive index layer 13 on a transparent substrate 11. The manufacturing method of the antireflection film includes the steps of: adding a gas or liquid to a coating liquid containing a silicone material, and forming cavities in the coating liquid; coating a substrate with the coating liquid containing the cavities and forming a coating film; and hardening the coating film and forming a low refractive index layer having the cavities. The method further includes agitating the coating liquid in a pressurized space and forming cavities in the coating liquid after adding the gas or liquid to the coating liquid containing the silicone material. After adding the gas or liquid to the coating liquid containing the silicone material, the agitation is carried out while applying an ultrasonic wave to the coating liquid to form the cavities in the coating liquid.

Description

  The present invention relates to an antireflection film provided for the purpose of preventing external light from being reflected on the surface of a window or display. In particular, the present invention relates to an antireflection film provided on the surface of a display such as a liquid crystal display (LCD), a CRT display, an organic electroluminescence display (ELD), a plasma display (PDP), a surface electric field display (SED), or a field emission display (FED). . In particular, it relates to an antireflection film provided on the surface of a liquid crystal display (LCD). Furthermore, the present invention relates to an antireflection film provided on the surface of a transmissive liquid crystal display (LCD).

  In general, a display is used in an environment where external light or the like enters regardless of whether the display is used indoors or outdoors. Incident light such as external light is specularly reflected on the display surface and the like, and the reflected image thereby mixes with the display image, thereby degrading the screen display quality. For this reason, it is essential to provide an antireflection function on the display surface or the like, and there is a demand for higher performance of the antireflection function and a combination of functions other than the antireflection function.

  In general, the antireflection function is obtained by forming an antireflection layer having a multilayer structure having a repeating structure of a high refractive index layer and a low refractive index layer made of a transparent material such as a metal oxide on a transparent substrate. These antireflection layers having a multilayer structure can be formed by a dry film forming method such as a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method.

  In the case of forming an antireflection layer using a dry film formation 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 the film formation is performed in a vacuum. There is a problem that productivity is low and it is not suitable for mass production. On the other hand, as a method for forming an antireflection layer, attention has been focused on production of an antireflection film by a wet film formation method using a coating liquid capable of increasing the area, continuously producing, and reducing the cost.

  In addition, in an antireflection film in which these antireflection layers are provided on a transparent substrate, since the surface thereof is relatively flexible, in order to impart surface hardness, an acrylic material is generally cured. A method of providing a hard coat layer obtained in this manner and forming an antireflection layer thereon is used. The hard coat layer is made of an acrylic material and has high surface hardness, gloss, transparency, and scratch resistance.

  When an antireflection layer is formed by a wet film formation method, it is produced by applying at least a low refractive index layer on a hard coat layer obtained by curing these ionizing radiation curable materials. Compared to the membrane method, it has the merit of being able to be manufactured at low cost, and is widely available in the market.

JP-A-2005-202389 JP 2005-199707 A JP-A-11-92750 JP 2007-121993 A JP 2005-144849 A JP 2006-159415 A JP 2010-008863 A JP 2010-085682 A International Publication No. 2010/038709

  By providing an antireflection film on the display surface, reflection of external light can be suppressed by the antireflection function, and contrast in a bright place can be improved. Further, since the transmittance can be improved at the same time, the image can be displayed brighter. It can also be expected to save energy by reducing the output of the backlight.

  In the antireflection film, an antireflection film excellent in antireflection performance and optical characteristics is required. In order to satisfy these characteristics, the existing antireflection layer film uses a technology to form a low refractive index layer using nanometer-sized silica particles, but in recent years, biotoxicity has been pointed out in these materials. Therefore, alternative materials are needed. An object of the present invention is to provide an antireflection film excellent in optical characteristics using a safe and inexpensive material.

In order to solve the above problems, the invention according to claim 1 is a method for producing an antireflection film having a low refractive index layer on a transparent substrate, wherein a gas or a liquid is added to a coating liquid containing a silicone material. A step of forming a void in the coating liquid, a step of applying a coating liquid containing the void on the substrate to form a coating film, and curing the coating film to form a low refractive index layer having a void. The manufacturing method of the antireflection film characterized by including the process to do.
According to a second aspect of the present invention, a gas or a liquid is added to the coating liquid containing the silicone material, and then stirred in a pressurized space to form a void in the coating liquid. It was set as the manufacturing method of the reflection prevention film of description.
The invention according to claim 3 is characterized in that after adding a gas or a liquid to the coating liquid containing the silicone material, stirring is performed while applying an ultrasonic wave to form a void in the coating liquid. It was set as the manufacturing method of the antireflection film of Claim 1.
Moreover, as invention concerning Claim 4, the gas or liquid added to the coating liquid containing the said silicone material is water, The antireflection film in any one of Claim 1 thru | or 3 characterized by the above-mentioned. It was set as the manufacturing method.
According to a fifth aspect of the present invention, the void included in the low refractive index layer to be formed has a spherical shape or a spherical approximate shape having a diameter in the range of 10 nm to 200 nm. It was set as the manufacturing method of the antireflection film in any one of thru | or 4.
Moreover, as invention concerning Claim 6, it was set as the antireflection film manufactured by the manufacturing method of Claims 1 thru | or 5.

  In the antireflection film according to the present invention, the antireflective film having a reduced reflectance can be obtained because the low refractive index layer is composed of a silicone material containing voids. Further, by using a transmissive liquid crystal display using an antireflection film, the contrast in a bright place can be improved as described above, and an image can be displayed brighter. Furthermore, energy saving effect can be expected.

It is a cross-sectional schematic diagram of the antireflection film of one Example of this invention. It is the schematic of the manufacturing process 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.

  In the antireflection film of the present invention, a hard coat layer and a low refractive index layer are provided on one surface of the transparent substrate. FIG. 1 shows a schematic cross-sectional view of the antireflection film (1) of the present invention. In the antireflection film (1) of the present invention shown in FIG. 1, a hard coat layer (12) and a low refractive index layer (13) are sequentially provided on one surface of the transparent substrate (11).

  In the antireflection film of the present invention, the low refractive index layer (13) includes a gap (14). The voids in the low refractive index layer are formed by adding a gas or a liquid to a coating liquid containing a silicone material, forming a void in the coating liquid, and applying the coating liquid containing the voids on a substrate. And a step of curing the coating film and forming a low refractive index layer having voids.

  The present inventor easily forms a void by forming a void by adding a gas or a liquid at the coating liquid stage using a silicone material, and forming a low refractive index layer on the transparent substrate using the coating liquid containing the void. In addition, the inventors have found that a low refractive index layer having voids in the low refractive index layer can be formed, and an antireflection film having sufficient antireflection performance can be obtained, and the present invention has been achieved.

  The transparent base material used for the antireflection film of the present invention will be described.

  As the transparent substrate in the antireflection film of the present invention, films or sheets made of various organic polymers can be used. For example, a base material usually used for an optical member such as a display can be cited, considering optical properties such as transparency and refractive index of light, and further various physical properties such as impact resistance, heat resistance and durability, 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 methacrylate, etc. Those made of organic polymers such as acrylic, polystyrene, polyvinyl chloride, polyimide, polyvinyl alcohol, polycarbonate, ethylene vinyl alcohol are used. In particular, polyethylene terephthalate, triacetyl cellulose, polycarbonate, and polymethyl methacrylate are preferable. Furthermore, functions can be added to these organic polymers by adding known additives such as antistatic agents, ultraviolet absorbers, infrared absorbers, plasticizers, lubricants, colorants, antioxidants, flame retardants, etc. Can also be used. The transparent substrate may be composed of one or a mixture of two or more selected from the above organic polymers, or a polymer, or may be a laminate of a plurality of layers. Moreover, as thickness of a transparent base film, it is preferable to use 35 micrometers or more and 120 micrometers or less. Moreover, when using triacetylcellulose, it is preferable to use the thickness of 35 micrometers or more and 80 micrometers or less. Moreover, when using a polyethylene terephthalate, it is preferable to use the thickness of 20 micrometers or more and 80 micrometers or less.

  Especially, since a triacetylcellulose film has little birefringence and favorable transparency, when using the antireflection film of this invention for a liquid crystal display, it can be used conveniently. The refractive index of the triacetyl cellulose film is about 1.50, which is lower than that of other transparent substrates. Moreover, the polyethylene terephthalate film used widely as a transparent base material is about 1.60.

  Next, the formation method of the hard-coat layer provided on a base material is demonstrated. As shown in FIG. 1, a hard coat layer is provided on a base material, and a low refractive index layer is formed on the hard coat layer. By providing the hard coat layer, high surface hardness can be imparted to the surface of the low refractive index layer of the antireflection film.

  The hard coat layer is formed by applying a coating liquid for forming a hard coat layer containing an ionizing radiation curable material and a solvent onto the transparent substrate to form a coating film, drying the coating film, and ionizing the dried coating film. It is formed by irradiating with radiation.

  An acrylic material can be used as the ionizing radiation curable material contained in the hard coat layer forming coating solution. 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, as ionizing radiation type materials, 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 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, 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 Ruji (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-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-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, etc. can be mentioned, but not limited thereto.

  In addition to these, as ionizing radiation-type materials, polyether resins, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, etc. having (meth) acrylate functional groups are used. can do.

  The hard coat layer forming coating solution contains a solvent. 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, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, methylcyclohexanone, methyl isobutyl ketone, methyl butyl ketone, diacetone alcohol, etc. Ketones, ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, Esters such as Onjo ethyl, n-pentyl acetate, and γ-ptyrolactone, cellosolves such as methyl cellosolve, cellosolve, butyl cellosolve, cellosolve acetate, alcohols such as ethanol and isopropyl alcohol, and N-methyl- Examples include 2-pyrrolidone and dimethyl carbonate. These can be used alone or in combination of two or more.

  The coating liquid for forming a hard coat layer can contain a photopolymerization initiator. When ultraviolet rays are used as the ionizing radiation for curing the coating film, a photopolymerization initiator is added to the coating liquid for forming the hard coat layer. Any photopolymerization initiator may be used as long as it generates radicals when irradiated with ionizing radiation. For example, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, and thioxanthones are used. be able to. The addition amount of the photopolymerization initiator is preferably in the range of 0.1 wt% or more and 10 wt% or less with respect to the ionizing radiation curable material, and more preferably 1 wt% or more and 8.5 wt% or less. preferable.

  Further, in the hard coat layer forming coating solution, other additives may be added to the hard coating layer forming coating solution in addition to the surface conditioner described above. . As the functional additive, an ultraviolet absorber, an infrared absorber, an adhesion improver, a curing agent, or the like can be used.

  Also, a conductive material can be added to the hard coat layer forming coating solution. By adding a conductive material to the hard coat layer-forming coating solution, an antistatic function can be imparted to the resulting antireflection film, and pride adhesion to the display surface can be prevented.

  As the conductive material, a quaternary ammonium salt material, metal oxide particles, a conductive polymer, or the like can be used.

As the quaternary ammonium salt material which is a conductive material, a material containing a quaternary ammonium salt material as a functional group in the molecule can be preferably used. Quaternary ammonium salt material -N ⁺ X ^- shows the structure of quaternary ammonium cation (-N ⁺⁾ and anion (X ^-) expressing the conductive hard coat layer by providing the. At this time, as X ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , F ⁻ , HSO ₄ ⁻ , SO ₄ ²⁻ , NO ₃ ⁻ , PO ₄ ³⁻ , HPO ₄ ²⁻ , H ₂ PO ₄ ⁻ , SO ₃ ^-, OH ^-, and the like can be given.

  Metal oxide particles used as the conductive material include zirconium oxide, antimony-containing tin oxide (ATO), phosphorus-containing tin oxide (PTO), tin-containing indium oxide, aluminum oxide, cerium oxide, zinc oxide, and aluminum-containing zinc oxide. In addition, conductive metal oxide particles mainly composed of one or more metal oxides selected from tin oxide, antimony-containing zinc oxide and indium-containing zinc oxide can be used.

  Examples of the conductive polymer used as the conductive material include polyacetylene, polyaniline, polythiophene, polypyrrole, polyphenylene sulfide, poly (1,6-heptadiyne), polybiphenylene (polyparaphenylene), polyparafinylene sulfide, polyphenylacetylene, One or a mixture of two or more selected from poly (2,5-thienylene) and derivatives thereof can be used.

  A coating liquid for forming a hard coat layer obtained by adjusting the above materials is applied on a transparent substrate by a wet film formation method, a coating film is formed, the coating film is dried, and ionizing radiation is applied to the coating film. By irradiating, a hard coat layer can be formed. The method for forming the hard coat layer is shown below.

  The coating liquid for forming a hard coat layer is applied on a transparent substrate to form a coating film. As a coating method for applying a coating liquid for forming a hard coat layer on a transparent substrate, 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, A coating method using a dip coater can be used. In addition, since the hard-coat layer of this invention is a thin coating film and needs to be a uniform film thickness, it is preferable to use the micro gravure coater method and the die coater method.

  Next, the solvent in the coating film is removed by drying the coating film of the hard coat layer formed on the transparent substrate. At this time, heating, blowing, hot air, or the like can be used as the drying means.

  Next, the hard coat layer is formed by irradiating the coating film obtained by applying the coating liquid for forming the hard coat layer on the transparent substrate with ionizing radiation.

  As the ionizing radiation, ultraviolet rays and electron beams can be used. In the case of ultraviolet curing, a light source such as a high pressure mercury lamp, a low pressure mercury lamp, an ultrahigh 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 can be used. . The electron beam preferably has an energy of 50 to 1000 KeV. An electron beam having an energy of 100 to 300 KeV is more preferable.

  In the antireflection film of the present invention, the thickness of the hard coat layer to be formed is preferably 3 μm or more and 10 μm or less, and the pencil hardness of the surface of the low refractive index layer is H in order to have sufficient scratch resistance. The above is preferable.

  In the antireflection film of the present invention, a low refractive index layer is formed on the hard coat layer. A method for forming the low refractive index layer will be described.

  The coating liquid for forming a low refractive index layer can be obtained by adding a gas or a liquid to a coating liquid containing a silicone material and forming voids in the coating liquid. A layer having a low refractive index (low refractive index layer) can be formed by forming a low refractive index layer using a coating liquid containing the voids. This is because the voids included in the low refractive index layer have a refractive index of air (≈1).

  As the silicone material contained in the coating solution for forming the low refractive index layer, a curing reaction type silicone material such as an addition reaction type, a condensation reaction type, a UV curing type, and an EB curing type can be used. More specifically, a typical dimethylsiloxane polymer as a compound having an organosiloxane as a basic skeleton, a methylphenylsiloxane polymer in which a part of the methyl group is substituted with a phenyl group, a part of the methyl group is a hydrogen atom And methylhydrogensiloxane polymer substituted with Further, an alkyl-modified siloxane polymer in which a part of the methyl group of the dimethylsiloxane polymer is substituted with an alkyl group, a higher fatty acid-modified siloxane polymer substituted with a higher fatty acid, a fluorine-modified siloxane polymer substituted with a functional group having a fluorine group, An amino-modified siloxane polymer substituted with a functional group having an amino group, an epoxy-modified siloxane polymer substituted with a functional group having an epoxy group, a carboxyl-modified siloxane polymer substituted with a functional group having a carboxyl group, a functional group having a hydroxyl group In addition to a hydroxyl group-containing siloxane polymer substituted with a methacryl-modified siloxane polymer substituted with a functional group having a methacryl group, a low molecular weight cyclic siloxane can also be mentioned. At this time, the silicone material may be used alone or in combination of two or more. Moreover, you may mix a silicone hardening | curing agent.

  Gas or liquid is added to the silicone material to form voids in the coating solution for forming the low refractive index layer. Examples of the gas or liquid added to the silicone material include a monomolecular gas, an organic solvent, water, an aqueous solvent, and the like, and a substance that does not cause curing inhibition can be used as appropriate. More specifically, gases such as hydrogen gas, helium gas, nitrogen gas, oxygen gas, argon gas, carbon dioxide gas, air and carbon dioxide, liquids such as liquid helium, liquid nitrogen, liquid oxygen and water, and dry ice Solids, alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol and ethylene glycol, aromatic hydrocarbons such as toluene, xylene, cyclohexane and cyclohexylbenzene, hydrocarbons such as n-hexane, dibutyl ether and dimethoxy Ethers such as methane, dimethoxyethane, diethoxyethane, propylene oxide, dioxane, dioxolane, trioxane, tetrahydrofuran, fluoroether, anisole and phenetole, methyl isobutyl ketone, methyl butyl keto Ketones such as acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, and methylcyclohexanone, and ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, It is appropriately selected from esters such as methyl propionate, ethyl propionate, n-pentyl acetate, and γ-ptyrolactone, and cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, cellosolve acetate, and the like.

  The timing for adding the gas or liquid for forming the voids can be added at the stage of preparing the coating liquid for forming the low refractive index layer. By adding a gas or liquid at the liquid preparation stage, uniform dispersion of the voids can be promoted. Further, the added gas or liquid is not limited to one kind, and a plurality of different kinds of substances may be used. Further, the amount of gas or liquid added to the coating liquid for forming a low refractive index layer can be appropriately changed in order to form an arbitrary void shape.

  In forming fine voids by adding a gas or liquid to a coating liquid containing a silicone material, a method of atomization such as stirring, mill dispersion, pressure dispersion, ultrasonic dispersion, nanobubbles or microbubbles is used. be able to. In the mill dispersion, a technique using inorganic fine particles as a dispersion aid can be applied. The inorganic fine particles can be removed by precipitation or filtering after the dispersion, but the inorganic fine particles may remain in the coating liquid after the dispersion.

  In forming a void in the coating liquid for forming a low refractive index layer containing a silicone material, it is preferable to add a gas or a liquid to the coating liquid containing a silicone material and then stir in a pressurized space. By adding a gas or liquid to the coating liquid and then stirring in a pressurized space, it is possible to easily form minute voids in the low refractive index forming coating liquid.

  In addition, in forming a void in a coating liquid for forming a low refractive index layer containing a silicone material, after adding a gas or a liquid to the coating liquid containing a silicone material, stirring may be performed while applying an ultrasonic wave. preferable. . By adding a gas or liquid to the coating liquid and then stirring while applying an ultrasonic wave, a minute gap can be easily formed in the coating liquid for forming a low refractive index.

  Moreover, water can be suitably used as the gas or liquid added to the silicone material. By adding a small amount of water, voids can be easily formed in the coating liquid containing the silicone material. In particular, by adding a small amount of water to the silicone material and stirring in a pressurized space, or adding a small amount of water to the silicone material and stirring while applying ultrasonic waves, A minute gap can be formed. Moreover, the water which generated the microbubble can also be used as water.

  When water is used as a gas or liquid added to the silicone material, water should be added within a range of 0.01 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the silicone material (including the curing agent). Is preferred. If the amount of water added exceeds 10, curing failure may occur. If the amount of water added is less than 0.01 parts by weight, a sufficient amount of voids may not be formed in the coating liquid.

  The coating liquid for forming a low refractive index layer in which voids are formed is applied onto the hard coat layer to form a coating film. As a coating method at this time, a coating method using 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, or a dip coater can be used.

  Next, the coating film is cured by heating or irradiating the coating film on the hard coat layer with ionizing radiation and non-ionizing radiation. The curing method is appropriately selected depending on the curing method (addition reaction type, condensation reaction type, UV curing type, EB curing type) of the silicone material. In addition, it may be irradiated with ionizing radiation or non-ionizing radiation after heating, and the process can be appropriately selected according to the characteristics of the coating solution for forming the low refractive index layer. After these processes, the heat treatment is performed again. You may do it.

  At this time, ultraviolet rays and electron beams can be used as the ionizing radiation. As in the case of forming the hard coat layer, a light source such as a high pressure mercury lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a carbon arc, or a xenon arc can be used for ultraviolet curing. 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 can be used. . The electron beam preferably has an energy of 50 to 1000 keV. An electron beam having an energy of 100 to 300 keV is more preferable. As the non-ionizing radiation, radio waves such as visible light, infrared rays, millimeter waves, and microwaves can be used.

  As described above, a low refractive index layer having voids is formed. In the low refractive index layer in the antireflection film of the present invention, by providing a void having an air refractive index (≈1) inside, it has a low refractive index and is provided on the surface of the antireflection film. Expresses antireflection performance.

  The film thickness (d) of the low refractive index layer is such that the optical film thickness (nd) obtained by multiplying the film thickness (d) by the refractive index (n) of the low refractive index layer is 1/4 of the wavelength of visible light. Is designed to be equal to The film thickness of the low refractive index layer is preferably 50 nm or more and 200 nm or less.

  The void included in the low refractive index layer in the antireflection film of the present invention preferably has a spherical shape or a spherical approximate shape having a diameter in the range of 20 nm to 200 nm. When the diameter of the void exceeds 200 nm, light is remarkably reflected by Rayleigh scattering, and the transparency of the antireflection film obtained by whitening the low refractive index layer tends to be lowered. On the other hand, when the diameter of the gap is less than 20 nm, the average luminous reflectance of the surface of the low refractive index layer of the antireflective film obtained by forming a layer structure having a high refractive index starts to increase. In the present invention, the diameter of the void in the low refractive index layer represents the maximum diameter of the void having a spherical shape or a spherical approximate shape, and the diameter of the void in the low refractive index is measured by observation with an electron microscope. The

  Moreover, it is preferable that the low refractive index layer in the antireflection film of the present invention has a refractive index with respect to a light source of 589 nm of the low refractive index layer in a range of 1.30 or more and less than 1.45. By making the refractive index of the low refractive index layer in the range of 1.30 or more and less than 1.45, an antireflection function can be imparted to the antireflection film. When the refractive index of the low refractive index layer exceeds 1.45, the resulting antireflection film may not be able to obtain a sufficient antireflection function. On the other hand, the refractive index of the low refractive index layer is preferably low, but in order to make it lower than 1.30, it is necessary to greatly increase the occupation ratio of the internal voids, which causes a decrease in strength. End up.

  In the antireflection film of the present invention, the average luminous reflectance on the surface of the low refractive index layer is preferably in the range of 0.3% or more and less than 2.0%. 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 luminous average 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 antireflection film of the present invention preferably has a total light transmittance of 90.0% or more. In the antireflection film having a total light transmittance of less than 90.0%, the transmittance is too low, so that it is not suitable for the antireflection film provided on the display surface.

  The antireflection film of the present invention is preferably formed continuously by a roll-to-roll method. FIG. 2 shows a schematic diagram of the production process of the antireflection film of one embodiment of the present invention. The web-shaped transparent substrate being wound is continuously run from the unwinding portion (31) to the winding portion (32). At this time, the transparent substrate (11) is applied to the coating unit (coating step (21)), By passing the heating / drying unit (heating / drying step (22)) and the ionizing radiation irradiation unit (ionizing radiation irradiation step (23)), the hard coat layer (12) is continuously formed on the transparent substrate (11). Is done. Thereafter, the low refractive index layer (13) is passed through the hardening step in the same manner, whereby the low refractive index layer (13) is formed on the hard coat layer (12), and the antireflection film (1) is applied. Can be manufactured. When the hard coat layer is formed, it is wound on a roll, and when the low refractive index layer is formed, the low refractive index layer may be formed again by a roll-to-roll method, or continuously after the hard coat layer is formed. Alternatively, a low refractive index layer may be formed and wound on a roll. The heating / drying unit (22) and the ionizing radiation curing unit (23) are appropriately selected depending on the curing type of the silicone material. The order of each unit can be changed as appropriate. Moreover, in FIG. 4, although the heat drying unit (22) is comprised from two units, a primary drying unit (22a) and a secondary drying unit (22b), each unit is comprised by two or more in this way. Also good.

  As described above, the antireflection film of the present invention can be obtained. In addition, in FIG. 1, although the antireflection layer which comprises a hard-coat layer and a low-refractive-index layer in order on a transparent base material is shown, this invention is not limited to this. A low refractive index layer having a hard coat property can also be formed by applying the coating liquid for forming a low refractive index layer having the voids with the thickness of the hard coat layer. At this time, the voids in the low refractive index layer may be segregated on the surface side (the side opposite to the base material).

  Next, an antireflection polarizing plate using the antireflection film of the present invention will be described. The cross-sectional schematic diagram of the anti-reflective polarizing plate using the anti-reflective film of one Example of this invention was shown in FIG.

  The antireflection polarizing plate (510) includes an antireflection film (1) comprising a hard coat layer (12) and a low refractive index layer (13) in this order on one surface of the first transparent substrate (11). Thus, the antireflective polarizing plate (510) having the first polarizing layer (53) and the second transparent substrate (52) in this order on the low refractive index layer non-forming surface side is obtained.

  The antireflection film (1) according to the embodiment of the present invention can be used as a part of a display member or an image device. Next, the configuration of a transmissive liquid crystal display using the antireflection film of the present invention will be described. FIG. 4 is a schematic cross-sectional view showing a transmissive liquid crystal display provided with the antireflection film of one embodiment of the present invention.

  In the transmissive liquid crystal display of FIG. 4A, the first polarizing plate (50) in which the antireflection film (1) 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 (500), a liquid crystal cell (60), a second polarizing plate (70), and a backlight unit (80) are provided in this order. At this time, the antireflection film (1) side becomes the observation side, that is, the display surface.

  In Fig.4 (a), it is a transmissive | pervious liquid crystal display provided with the transparent base material (11) of an antireflection film (1), and the transparent base material of a 1st polarizing plate (50) separately.

  The backlight unit (80) includes a light source and a light diffusion plate. The liquid crystal cell (60) 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 (60), the polarizing layer (53, 73) is sandwiched between the transparent substrates (51, 52, 71, 72). It has become.

  Moreover, in FIG.4 (b), the antireflective film (1) 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 On the non-formed surface, a polarizing layer (53) and a transparent substrate (52) are provided in this order to form an antireflection polarizing plate (510), and the antireflection polarizing plate (510), liquid crystal cell (60), Two polarizing plates (70) and a backlight unit (80) are provided in this order. At this time, the low refractive index layer (13) side of the antireflection film (1) is the observation side, that is, the display surface.

  In FIG. 4B, a polarizing layer (53) and a transparent substrate (52) are provided in this order as a first polarizing plate on the surface of the antireflective film (1) where the low refractive index layer is not formed. A transmissive liquid crystal display provided with the antireflection polarizing plate (510).

  In FIG. 4B as well, as in FIG. 4A, the backlight unit (80) 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 (60), the polarizing layer (53, 73) is sandwiched between the transparent base materials (11, 52, 71, 72). 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 Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.

  A PET film (thickness 80 μm, refractive index 1.67) was prepared as a transparent substrate.

(Coating liquid for forming hard coat layer)
・ Pentaerythritol triacrylate 100 parts by weight ・ Photopolymerization initiator (product name: Irgacure 184, manufactured by Ciba Japan Co., Ltd.) 10 parts by weight is dissolved in methyl ethyl ketone so that the solid content is 50% to form a hard coat layer. Coating liquid 1 was prepared.

(Formation of hard coat layer)
The said coating liquid for hard-coat layer formation was apply | coated to the single side | surface of PET film (film thickness of 80 micrometers), and after the primary drying at 25 degreeC for 60 second, the secondary drying was subsequently performed at 80 degreeC for 60 second. After drying, a transparent hard coat layer having a dry film thickness of 5 μm was formed by performing ultraviolet irradiation at an irradiation dose of 300 mJ / m ² using an ultraviolet irradiation device (Fusion UV System Japan, light source H bulb).

  Next, a low refractive index layer is formed on the hard coat layer to produce an antireflection film. An example of preparation of a coating solution for forming a low refractive index layer used at that time is shown below.

(Coating liquid for low refractive index layer formulation example 1)
・ Silicon base (made by Shin-Etsu Silicone, trade name: KE-106) 100 parts by weight ・ Silicone curing agent (Shin-Etsu Silicone, trade name: CAT-RG) 10 parts by weight ・ Surface conditioner (by BYK, trade name: BYK-025) 0 .3 parts by weight, and after stirring these, add 1 part by weight of pure water, stir for 10 minutes in a pressurized space of 5 atm, and then release to atmospheric pressure to release coating solution 1 for the low refractive index layer. Prepared.

(Formation example 2 for coating liquid for forming a low refractive index layer)
・ Using 100 parts by weight of silicone (product name: UVHV1101) manufactured by Momentive Performance Material, after stirring these, add 1 part by weight of pure water in which microbubbles of oxygen were generated, and stirring while adding ultrasonic waves By performing, the coating liquid 2 for low refractive index layers was prepared.

  (Example 1) and (Example) by forming a low refractive index layer on the hard coat layer using the coating liquid for forming a low refractive index layer (Formulation Example 1) and (Formulation Example 2). The antireflection film of 2) is obtained.

Example 1
As a specific method for forming the low refractive index layer, the coating conditions are such that the film thickness after curing the coating solution for forming the low refractive index layer of (Formulation Example 1) is 100 nm on the hard coat layer. Was set and applied. After the first drying (heating) was performed at a temperature of 100 ° C. for 30 seconds, the second drying (heating) was performed at a temperature of 80 ° C. for 300 seconds to be cured to form a low refractive index layer, thereby producing an antireflection film.

(Example 2)
As a specific method for forming the low refractive index layer, the low refractive index layer forming coating liquid of (Formulation Example 2) was applied on the hard coat layer so that the film thickness after drying was 100 nm. After the first drying (heating) is performed at a temperature of 25 ° C. for 25 seconds, the second drying (heating) is performed at a temperature of 80 ° C. for 50 seconds, and an ultraviolet irradiation device (manufactured by Fusion UV System Japan Co., Ltd., light source H bulb) is used. An antireflection film was produced by irradiating with ultraviolet rays at an irradiation dose of 600 mJ / m ² to form a low refractive index layer.

  The antireflection film produced in (Example 1) and (Example 2) was measured and evaluated as follows.

"Visibility average reflectance"
The surface of the obtained antireflection film opposite to the surface on which the low refractive index layer was formed was applied in black by a black matte spray. After coating, the low refractive index layer formation surface measured using an automatic spectrophotometer (manufactured by Hitachi, Ltd., U-4000) is averaged from the spectral reflectance at an incident angle of 5 ° under the condition of a C light source and a 2-degree field of view. The reflectance (Y%) was calculated. In addition, the photopic standard relative luminous sensitivity was used as the specific luminous efficiency.

“Measurement of haze (H) and parallel light transmittance”
About the obtained anti-reflective film, haze (H) and parallel light transmittance were measured using the image clarity measuring device (Nippon Denshoku Industries Co., Ltd. make, NDH-2000).

“Measurement of surface resistance”
The surface of the low-refractive index layer of the obtained antireflection film was measured with a high resistivity meter (manufactured by Dia Instruments, High Lester MCP-HT260) according to JIS-K6911.

"Confirmation of uneven color interference fringes"
The back surface of the obtained antireflection film was painted black with a spray ink, and the state of the coated surface was visually confirmed.
The visually confirmed evaluation is as follows.
○: Color unevenness and interference fringes were not confirmed.
X: Color unevenness and interference fringes were confirmed.

  Table 1 shows the measurement / confirmation results of the luminous average reflectance, haze, parallel light transmittance, surface resistance value, and color uneven interference fringes of the antireflection film obtained.

  In the antireflection film obtained in (Example 1) and (Example 2), it was possible to provide an antireflection film excellent in optical characteristics using a silicone material that is safe and low in production cost. .

  The refractive indexes of the low refractive index layers obtained from the spectral reflectance curves for the antireflection films obtained in (Example 1) and (Example 2) are 1.38 (Example 1) and 1.36, respectively. (Example 2).

  Moreover, about the anti-reflective film obtained in (Example 1) and (Example 2), as a result of performing cross-sectional observation by a transmission electron microscope, it was confirmed that a space | gap is a spherical shape or a spherical approximate shape. At this time, the diameter of the gap was 20 to 80 nm in the antireflection film obtained in (Example 1), and 50 to 80 nm in the antireflection film obtained in (Example 2). It was.

  The antireflection film of the present invention includes a reflection film such as a window or a display, a diffusion film, a prism sheet, a brightness enhancement film, a touch panel, a liquid crystal cell, a member or lens for compensating optical characteristics of a polarizing plate, and a prism element. It can be applied to all members that should prevent reflection, such as light emitting diodes, photodiodes, CCDs, and lighting equipment.

DESCRIPTION OF SYMBOLS 1 Antireflection film 11 Transparent base material or 1st transparent base material 12 Hard-coat layer 13 Low-refractive-index layer 14 Space | gap 21 Application | coating process (unit)
22 Heating and drying process (unit)
22a Primary drying process (unit)
22b Secondary drying process (unit)
23 Ionizing radiation irradiation process (unit)
DESCRIPTION OF SYMBOLS 31 Unwinding part 32 Winding part 50 1st polarizing plate 52 2nd transparent base material 53 1st polarizing layer 60 Liquid crystal cell 70 2nd polarizing plate 71 3rd transparent base material 72 4th transparent base material 73 Second polarizing layer 80 Backlight unit 500 Antireflection polarizing plate 510 Antireflection polarizing plate

Claims (6)

A method for producing an antireflection film comprising a low refractive index layer on a transparent substrate,
Adding a gas or liquid to a coating liquid containing a silicone material to form voids in the coating liquid;
Applying a coating liquid containing the voids on a substrate to form a coating film;
A method for producing an antireflection film, comprising: a step of curing the coating film and forming a low refractive index layer having voids.   The method for producing an antireflection film according to claim 1, wherein after adding a gas or a liquid to the coating liquid containing the silicone material, stirring is performed in a pressurized space to form a void in the coating liquid.   The method for producing an antireflection film according to claim 1, wherein after adding a gas or a liquid to the coating liquid containing the silicone material, stirring is performed while applying ultrasonic waves to form voids in the coating liquid. .   The method for producing an antireflection film according to claim 1, wherein the gas or liquid added to the coating liquid containing the silicone material is water.   5. The antireflection film according to claim 1, wherein the voids included in the formed low refractive index layer have a spherical shape or a spherical approximate shape having a diameter in the range of 10 nm to 200 nm. Manufacturing method.   An antireflection film produced by the production method according to claim 1.

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