JP5895657B2 - Manufacturing method of optical film - Google Patents

Description

  The present invention relates to an optical film, a method for producing the optical film, a polarizing plate using the optical film, a glass scattering prevention film for an image display device, a touch panel, and a liquid crystal display device.

  Anti-reflective layer that reduces surface reflection to improve transmittance and contrast and reduce glare mainly in optical lenses, portable terminals, portable terminals with touch panel functions, image display devices such as computers and televisions, etc. An antireflection film having the following has been proposed.

  On the other hand, portable terminals, portable terminals having a touch panel function, and the like are required to be used outdoors, downsized, and thinned, and the members used in the portable terminals are also desired to be thinned. ing. In addition, since the portable terminal is often used outdoors, durability is required for a member to be used. As the antireflection layer, it is effective to reduce light reflection at the interface between the laminate and the air by laminating several layers having appropriate values of refractive index and optical film thickness as the optical interference layer.

  As the optical interference layer, at least a low refractive index layer is provided. The low refractive index layer contains fine particles having a lower refractive index than the base film (for example, hollow silica fine particles having an outer shell layer that is porous or hollow inside, magnesium fluoride fine particles, etc.) to lower the refractive index. It is common to do. In addition, in order to impart mechanical strength, the antireflection film is generally an antireflection film in which a hard coat layer is formed as an intermediate layer on a base film, and hard coat properties are imparted, and usually hard coat properties. In the antireflection film having, after the hard coat layer is applied, the antireflection layer is coated on the hard coat layer.

  In recent years, from the viewpoint of productivity and low cost, various techniques for forming a hard coat layer and an antireflection layer (specifically, a fine particle localized (localized) phase) in a single coating process have been studied, for example, It is disclosed in Patent Literature 1 and Patent Literature 2.

Patent Document 1 discloses (A) a polymerizable compound, (B) a particle having a refractive index of 1.40 or less, and (D) a step of applying a curable composition containing a solvent on a cellulose resin substrate, curable properties. An antireflection laminate comprising the step of curing the composition to form a cured film on the cellulose resin substrate, wherein the particles are unevenly distributed on the surface opposite to the surface in contact with the cellulose resin substrate in the cured film A method for producing a body, wherein (D) in 100% by mass of a solvent, (D1) a base material cellulose resin is dissolved, and a solvent having a boiling point at 0.1 MPa of 80 ° C. or more and 250 ° C. or less is a specific range. It is a manufacturing method of the laminated body for reflection prevention contained in. In the technique, particles having a refractive index of 1.40 or less are formed on a surface opposite to the surface in contact with the cellulose resin substrate by applying and curing the curable composition once on the cellulose resin substrate. This is a technique for forming an anti-reflection laminate that forms both high-density layers and has both scratch resistance and low refractive index.
Patent Document 2 forms a coating film by applying an ultraviolet curable resin composition containing components (A) to (D), and forms two or more layers by evaporating the solvent from one coating film. It is a manufacturing method of a laminated body. (A) Metal oxide particles obtained by bonding an organic compound having a polymerizable unsaturated group, (B) an ethylenically unsaturated group-containing fluoropolymer, (C) a fast volatile solvent, and (D) a slow volatile solvent. In the technique, two or more layers are formed by evaporating the solvent from one coating film obtained by applying the ultraviolet curable resin composition on the substrate, and a layer having a high fluorine content is obtained as the outermost layer. The film is excellent in antireflection.

  However, in response to demands for miniaturization and thinning, an antireflection film in which a hard coat layer and fine particle unevenly distributed (localized) phases are formed in a single coating process using a thin film substrate film is used, and the film is used for carrying When durability tests were conducted assuming the use of outdoor applications such as terminals, there was a problem that curling and flexibility (flexibility, flexibility) deteriorated. These have led to a decline in the commercial value, and an immediate solution has been desired.

JP 2011-203560 A Japanese Patent No. 474825

  The present invention has been made in view of the above-described problems and situations, and the problem to be solved is that a hard coat layer and a fine particle localized phase are formed in a single coating process using a thin film substrate film (hereinafter referred to as a single layer). It is also an optical film excellent in antireflection and providing an optical film excellent in curling and flexibility (flexibility) after a durability test. Moreover, it is providing the manufacturing method of the said optical film, the polarizing plate using the said optical film, the glass scattering prevention film for image display apparatuses, a touch panel, and a liquid crystal display device.

  In order to solve the above-mentioned problems, the present inventor has a functional layer formed of a single layer containing a resin material and fine particles dispersed in the resin material in the process of examining the cause of the above-mentioned problem. An optical film, wherein the functional layer includes fine particles having a specific refractive index in a region less than ½ L in the thickness direction from the surface opposite to the base film when the layer thickness is L. An optical film having a localized phase contained at a specific ratio and having the functional layer formed on a surface on which the matting agent of the base film is localized is used after an endurance test. The present inventors have found that an optical film excellent in curling and flexibility (flexibility) can be obtained, and have reached the present invention.

  That is, the said subject which concerns on this invention is solved by the following means.

1. An optical film in which a functional layer containing a resin material and fine particles dispersed in the resin material is formed as a single layer on at least one surface of a base film containing a matting agent having a primary average particle size of 20 nm or less The substrate film is a solution casting in which a dope is cast on a belt-like metal support so that the matting agent is localized on the air surface side during belt casting. The coating composition formed by the film forming method and forming the functional layer satisfies the following (A) to (C), and the coating composition is formed on the base film so that the thickness after drying becomes 1 μm or more. After coating, curing is performed, and when the thickness of the functional layer is L, the fine particles contained in the functional layer in a region less than 1/2 L in the thickness direction from the surface opposite to the base film containing more than 50 wt% localized phase is formed, and the functions of Method for producing an optical film, wherein the layer, thereby forming the surface on which the matting agent of the base film is localized.
(A) The resin material is a curable resin.
(B) The fine particles have a refractive index lower than that of the resin material by 0.04 or more.
(C) An organic solvent that swells or dissolves the base film is contained.

2. 2. The method for producing an optical film according to item 1, wherein the fine particles have a refractive index in the range of 1.35 to 1.45.

3. The method for producing an optical film according to item 1 or 2 , wherein the substrate film is a cellulose ester film .

4). The film thickness of the said base film exists in the range of 5-40 micrometers, The manufacturing method of the optical film as described in any one of Claims 1-3 characterized by the above-mentioned.

  By the above means of the present invention, an optical film excellent in antireflection in which a hard coat layer and a fine particle localized phase are formed in a single coating process using a thin film substrate film, and curls and flexibility after a durability test ( An optical film excellent in flexibility can be provided.

  Moreover, the polarizing plate using the said optical film, the glass scattering prevention film for image display apparatuses, a touch panel, and a liquid crystal display device can be provided.

  The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

  The inventor is an optical film excellent in antireflection in which a thin film base film is used and a hard coat layer and a fine particle localized phase are formed as a functional layer in a single coating process, As a result of studying the cause of the above-mentioned problems in order to solve the problem of deterioration of flexibility (flexibility), additives and base films added to obtain a plastic effect and the like when forming the base film When a functional layer is formed on a base film that is uniformly mixed with a matting agent added to prevent blocking and handleability, the plasticizer in the base film partially dissolves in the functional layer. It is estimated that curl degradation is caused by the decrease in the elastic modulus of the base film and the significant decrease in the elastic modulus of the base film in the durability test. In particular, in a thin film substrate film, curl deterioration was significant because the stiffness of the substrate film itself was weak.

  In addition, it is considered that the durability test causes a reaction between the additive of the base film and the resin component of the functional layer, and the flexibility (flexibility) is deteriorated.

  For this reason, by providing the functional layer on the mat agent unevenly distributed (localized) surface of the thin film base film produced by the film forming method in which the additive and the mat agent are unevenly distributed (localized) in the front and back surface regions. It is estimated that an optical film excellent in antireflection with excellent curling and flexibility (flexibility) after durability test can be obtained because the reaction with additives is suppressed, and the elastic modulus of the base film can be suppressed. doing.

Cross-sectional photograph of the hard coat film of the present invention Schematic cross-sectional view using glass scattering prevention film for image display device in image display device Schematic diagram of polarizing plate 101

The method for producing an optical film of the present invention has a function of containing a resin material and fine particles dispersed in the resin material on at least one surface of a base film containing a matting agent having a primary average particle diameter of 20 nm or less. A method for producing an optical film in which a conductive layer is formed as a single layer, wherein the base film is a belt-like metal support so that the matting agent is localized on the air surface side during belt casting. The coating composition that is formed by a solution casting film forming method in which a dope is cast on the coating layer and that forms the functional layer satisfies the following (A) to (C), and the coating composition has a thickness after drying. After applying to the base film to be 1 μm or more and curing, when the thickness of the functional layer is L, from the surface on the opposite side of the base film to a region less than 1/2 L in the thickness direction, Contains 50% by mass or more of the fine particles contained in the functional layer. The localized phase is formed, and the functional layer, the matting agent of the substrate film and forming the surface to be localized.
(A) The resin material is a curable resin.
(B) The fine particles have a refractive index lower than that of the resin material by 0.04 or more.
(C) An organic solvent that swells or dissolves the base film is contained.

This feature is a technical feature common to the inventions according to claims 1 to 4 .

  The “single layer” in the case of the “functional layer formed by a single layer” in the present invention means a layer that can be formed by a single coating step, and the same resin material is used. It means that the layer exists continuously.

  In addition, the “refractive index” in this specification refers to the refractive index of Na-D line (wavelength 589 nm) at 25 ° C. The “refractive index of the particles” in the present specification is 25% in accordance with JIS K7105, in which a composition having a particle content of 1% by mass, 10% by mass, and 20% by mass is formed in the same matrix. The refractive index of Na-D line at ° C. is measured, and the value of the particle content of 100% by mass calculated by the calibration curve method is used.

  The “surface on which the matting agent of the base film is localized” in the present invention is defined as follows.

  After taking a tomographic photograph of the base film with a transmission electron microscope, the number of matting agents in the range of 2 μm in thickness and 25 μm in width from the side in contact with air was observed on both sides of the base film. When the number of matting agents is A, the number of matting agents is A, the number of matting agents in tomography is B, and the number of matting agents is B, the A / B Is greater than 1.01 times, the matting agent is defined to be localized on the A plane. More preferably, A / B is 1.05 times or more.

  As an embodiment of the present invention, the refractive index of the fine particles is preferably in the range of 1.35 to 1.45 from the viewpoint of manifesting the effects of the present invention. Moreover, it is preferable that a functional layer contains curable resin, it is preferable that the said base film is a cellulose ester film, and the film thickness of the said base film is in the range of 5-40 micrometers. In view of the effects of antireflection, curling and flexibility, it is preferable.

Further, in the present invention, the base film is formed by a solution casting film forming method in which a dope is cast on a belt-shaped metal support, and the matting agent is locally formed on the air surface side during belt casting film forming. that have Mashimashi. This ensures that the optical film is obtained having excellent curl and flexibility after the durability test (bending property).

  The optical film of the present invention can be suitably included in a polarizing plate, a glass scattering prevention film for an image display device, a touch panel and a liquid crystal display device.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<Functional layer>
(Resin material)
The resin material is easy to obtain the object effect of the present invention, and is excellent in mechanical film strength (abrasion resistance, pencil hardness). Therefore, the resin material is irradiated with active rays (also called active energy rays) such as ultraviolet rays and electron beams. A resin (curable resin) that cures through a crosslinking reaction is preferable. Specifically, UV curable acrylate resins (UV curable urethane acrylate resins, UV curable polyester acrylate resins, UV curable epoxy acrylate resins, UV curable polyol acrylate resins, etc.), or UV curable resins An epoxy resin or the like is preferably used, and an ultraviolet curable acrylate resin is particularly preferable.

  As the ultraviolet curable acrylate resin, a polyfunctional acrylate is preferable. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. Here, the polyfunctional acrylate is a compound having two or more acryloyloxy groups or methacryloyloxy groups in the molecule. Examples of the polyfunctional acrylate monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate. , Tetramethylolmethane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tri / tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, glycerol triacrylate relay , Dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol di Methacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pen Pentaerythritol tetramethacrylate, glycerol trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol penta methacrylate, dipentaerythritol hexa methacrylate, etc. isocyanurate derivatives of the active energy ray-curable are preferably exemplified. Among these, pentaerythritol tri (meth) acrylate and pentaerythritol tetra (meth) acrylate are preferable. The active energy ray-curable isocyanurate derivative may be a compound having a structure in which one or more ethylenically unsaturated groups are bonded to the isocyanuric acid skeleton, and isocyanuric acid triacrylate, isocyanuric acid diacrylate, ε-caprolactone. Examples include modified tris- (acryloxyethyl) isocyanurate. As a commercial item of an isocyanuric acid triacrylate compound, Shin-Nakamura Chemical Co., Ltd. A-9300 etc. are mentioned, for example. As a commercial item of an isocyanuric acid diacrylate compound, Toagosei Co., Ltd. Aronix M-215 etc. are mentioned, for example. Examples of the mixture of the isocyanuric acid triacrylate compound and the isocyanuric acid diacrylate compound include Aronix M-315 and Aronix M-313 manufactured by Toagosei Co., Ltd. Examples of ε-caprolactone-modified tris- (acryloxyethyl) isocyanurate include A-9300-1CL manufactured by Shin-Nakamura Chemical Co., Ltd. and Aronix M-327 manufactured by Toagosei Co., Ltd.

  Commercial products other than the active energy ray-curable isocyanurate derivatives include Adekaoptomer N series, Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612. (Sanyo Chemical Industries, Ltd.), Aronix M-6100, M-8030, M-8060, Aronix M-215, Aronix M-315, Aronix M-313, Aronix M-327 (manufactured by Toagosei Co., Ltd.) , NK-ester A-TMM-3L, NK-ester AD-TMP, NK-ester ATM-35E, NK ester A-DOG, NK ester A-IBD-2E, A-9300, A-9300-1CL (Shin Nakamura Chemical Industry Co., Ltd.), PE-3A (Kyoeisha Chemical) and the like.

You may mix the said curable resin individually or in mixture of 2 or more types. A monofunctional acrylate may also be used.
Monofunctional acrylates include isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, lauryl acrylate, isooctyl acrylate, tetrahydrofurfuryl acrylate, behenyl Examples include acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and cyclohexyl acrylate. Such monofunctional acrylates can be obtained from Nippon Kasei Kogyo Co., Ltd., Shin-Nakamura Chemical Co., Ltd., Osaka Organic Chemical Co., Ltd., etc.

  When using a monofunctional acrylate, it is preferable to contain in the range of polyfunctional acrylate: monofunctional acrylate = 80: 20-98: 2 by the mass ratio of polyfunctional acrylate and monofunctional acrylate. Examples of other resin materials include vinyl compounds, epoxy compounds, and alkoxymethylamine compounds. Examples of vinyl compounds include divinylbenzene, ethylene glycol divinyl ether, diethylene glycol divinyl ether, and triethylene glycol divinyl ether. As epoxy compounds, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, glycerin triglycidyl ether, etc. Can be mentioned. Examples of the alkoxymethylamine compound include hexamethoxymethylated melamine, hexabutoxymethylated melamine, tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril and the like. Moreover, as a refractive index of the said resin material, 1.49 or more are preferable, More preferably, it is the range of 1.49-1.6.

(Solvent that dissolves or swells the base film)
The solvent for dissolving or swelling the base film will be described. Examples of the solvent for dissolving or swelling the base film include the following solvents when the base film is made of a cellulose ester resin film, but the present invention is not limited thereto.

  Ethers having 3 to 12 carbon atoms: specifically, propylene glycol monomethyl ether, dibutyl ether, dimethoxymethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3, 5-trioxane, tetrahydrofuran, anisole and phenetole.

  Ketones having 3 to 12 carbon atoms: specifically, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, and the like.

  Esters having 3 to 12 carbon atoms: specifically, ethyl formate, propyl formate, formic acid-n-pentyl, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, acetic acid-n-pentyl, ethyl lactate, And γ-ptyrolactone.

Organic solvent having two or more kinds of functional groups: Specifically, methyl 2-methoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-methoxyethanol, 2-propoxyethanol, 2-butoxyethanol, 1 , 2-acetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, and ethyl acetoacetate.
Amides: dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like.
These can be used singly or in combination of two or more.

  As the solvent for dissolving or swelling the base film, cyclohexanone, methyl ethyl ketone, and γ-butyrolactone are preferable.

  When a solvent that swells or dissolves the base film is present in the functional composition coated on the base film made of cellulose ester resin, part of the cellulose ester resin is dissolved. Since the dissolved cellulose ester resin is hydrophilic, the applied functional composition has increased hydrophilicity in the vicinity of the base film, and the relatively hydrophobic particles described later are unevenly distributed on the side opposite to the base ( Is considered to be localized).

  As content of the solvent which melt | dissolves or swells the base film in a functional composition, it is the range of 1-200 mass% with respect to 100 mass parts of resin materials, Preferably it is the range of 1-100 mass%. is there.

(Solvent that does not dissolve or swell the base film)
The functional composition can also contain a solvent that does not dissolve or swell the base film. Solvents that do not dissolve or swell the base film include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2-butanol, cyclohexane Examples include hexanol, propylene glycol monoethyl ether, isobutyl acetate, methyl isobutyl ketone, 2-octanone, 2-pentanone, 2-hexanone, 2-heptanone, 3-pentanone, 3-heptanone, 4-heptanone, and toluene. As content, it is the range of 1-200 mass% with respect to 100 mass parts of resin materials.

(Fine particles)
The fine particles contained in the functional layer according to the present invention will be described. The fine particles contained in the functional layer according to the present invention refer to particles having a number average particle diameter of 400 nm or less when measured with a transmission electron microscope. In this case, the particle diameter of each particle is defined as the diameter when the projection plane in the transmission electron microscope is converted into a circle of the same volume. In order not to cause unnecessary scattering, the particle diameter of the fine particles is preferably sufficiently smaller than that of visible light, specifically 1 to 200 nm is preferable, more preferably 1 to 100 nm, particularly Preferably it is the range of 5-60 nm. The shape of the particles is not limited to a spherical shape, and may be an irregular shape.

  Further, the fine particles are fine particles having a refractive index lower than that of the resin material by 0.04 or more. Specifically, the refractive index is in the range of 1.35 to 1.45, and further has hydrophobicity. preferable. By including such fine particles, when the thickness of the functional layer is L, the functional layer is formed in a region less than ½ L in the thickness direction from the surface of the functional layer opposite to the base film. When a localized phase containing 50% by mass or more of the fine particles contained in the layer is formed, and further when the localized phase is formed, an excellent low refractive index property is obtained and the antireflection effect is excellent.

Specific examples of the fine particles include (organo) silica sol, titanium oxide sol, alumina oxide sol, tin oxide, hollow silica particles, and metal fluoride particles. Among these fine particles, organosilica sol and hollow silica particles are preferable, and hollow silica particles are more preferable. Further, the fine particles are preferably uniformly and finely dispersed, and are preferably present as primary particles. As a commercially available organosilica sol, for example, manufactured by Nissan Chemical Industries, Ltd .: MEK-AC-2101 (solvent: methyl ethyl ketone, specific gravity (20 ° C.): 1.011, average primary particle size 12 nm, viscosity (20 ° C.): 1. 1 mPa · s SiO ₂ : 30.6% moisture: 0.16), manufactured by Nissan Chemical Industries, Ltd .: MEK-AC-4101 (solvent: methyl ethyl ketone, specific gravity (20 ° C.): 1.006, average primary particle size 43 nm , Viscosity (20 ° C.): 3.2 mPa · s SiO ₂ : 30.7% moisture: 0.06%) and the like.

  Since hollow silica particles have cavities inside, hollow silica particles can have a lower refractive index than non-hollow particles.

  Examples of commercially available hollow silica particles include “JX1008SIV” manufactured by JGC Catalysts & Chemicals Co., Ltd. (number average particle diameter 50 nm, solid content 20% by mass, isopropyl alcohol solvent obtained with a transmission electron microscope), “JX1009SIV” ( And a number average particle diameter of 50 nm, a solid content of 20% by mass, and a methyl isobutyl ketone solvent) obtained with a transmission electron microscope.

  In addition, hydrophobic treatment can be performed by modifying fine particles such as hollow silica particles. Examples of the particle modifier that modifies fine particles such as hollow silica particles include compounds having a polymerizable unsaturated group and a hydrolyzable silyl group (hereinafter also referred to as “polymerizable particle modifier”). Examples of the polymerizable unsaturated group of the polymerizable particle modifier include a vinyl group and a (meth) acryloyl group. The hydrolyzable silyl group is a group that reacts with water to produce a silanol group (Si—OH). For example, one or more methoxy groups, ethoxy groups, n-propoxy groups, isopropoxy groups on silicon. A group, an alkoxyl group such as an n-butoxy group, an aryloxy group, an acetoxy group, an amino group, or a halogen atom is bonded.

  Commercially available products such as methacryloyloxypropyltrimethoxysilane can also be used as the polymerizable particle modifier. Further, as the particle modifier, a compound having a hydrolyzable silyl group containing fluorine (hereinafter, also referred to as “fluorine-containing particle modifier”) can be used.

  By using the fluorine-containing particle modifier, the hollow silica particles can be unevenly distributed on the surface opposite to the base film efficiently.

  As the fluorine-containing particle modifier, commercially available products such as tridecafluorooctyltrimethoxysilane can be used. Moreover, the particle modifier which has an alkyl group, and the particle modifier which has a silicone chain can be used similarly to a fluorine-containing particle modifier. The above various particle modifiers may be used alone or in combination of two or more.

  In order to modify the fine particles such as the hollow silica particles, the fine particles such as the hollow silica particles and the particle modifier may be mixed and hydrolyzed to bond them together.

  The binding amount of the particle modifier for fine particles such as hollow silica particles is preferably in the range of 0.01 to 40% by mass, more preferably 0, when the fine particles such as hollow silica particles after modification are 100% by mass. 0.1 to 30% by mass, particularly preferably 1 to 20% by mass. By setting the amount of the particle modifier to be reacted with fine particles such as hollow silica particles in the above range, not only can the dispersibility of the fine particles such as hollow silica particles in the functional composition be improved, but also the cured product obtained can be obtained. The effect of increasing transparency can be expected.

In the functional composition, the content of the fine particles can be appropriately adjusted according to the thickness of the cured film to be formed. For example, when the thickness of the cured film is 10 μm, when the total of components excluding the solvent is 100% by mass, the range is preferably 0.4 to 1.2% by mass, more preferably 0.5 to 1% by mass. % Range. For example, when the thickness of the cured film is 7 μm, it is preferably in the range of 0.6 to 1.8 mass%, more preferably in the range of 0.7 to 1.5 mass%, and the thickness of the cured film is 1 μm. As described above, in the case of 3 μm, the range is preferably 1.2 to 4% by mass, more preferably 1.5 to 3% by mass.
When the content of the fine particles is less than the above range, the antireflection ability (low refractive index) may not be obtained. On the other hand, if the content of the fine particles exceeds the above range, the thickness of the layer in which fine particles exhibiting antireflection ability exist at a high density becomes too large, and the reflectance reduction effect may not be exhibited.

(Localized phase)
FIG. 1 is an actual cross-sectional photograph of the functional layer of the present invention. FIG. 1B is an enlarged view of the localized phase portion of FIG.

  The localized phase referred to in the present invention is contained in the functional layer in a region less than 1/2 L in the thickness direction opposite to the transparent substrate film, where L is the total thickness of the functional layer. A phase containing 50% by mass or more of fine particles.

  When the cross-sectional photograph is observed, when the total thickness of the functional layer is L, fine particles are locally distributed in a region less than 1/2 L in the thickness direction opposite to the base film to form a localized phase. You can see that In the present invention, the localized phase contains 50% by mass or more of all fine particles contained in the functional layer. More preferably 70% by mass or more is preferable for achieving both scratch resistance and haze, and particularly preferably 90% by mass or more.

  The layer in which the fine particles in the functional layer in the present invention are locally distributed (localized phase) is obtained by taking a tomographic image of an optical film with a transmission electron microscope at a magnification of 5000 times, It can confirm by calculating | requiring the content mass% of the fine particle contained in the area | region less than 2L.

  In addition, by performing element mapping by elemental analysis, it is possible to determine the content mass% of fine particles by region.

  The thickness of the localized phase is preferably thin in the vicinity of the functional layer surface from the viewpoint of antireflection and excellent curling and flexibility resistance after the durability test, specifically 0.03-0.5 μm. It is preferable to be within the range. More preferably, it exists in the range of 0.05-0.5 micrometer.

(Functional layer thickness)
The functional layer is formed by a coating method to be described later, and the coating amount at that time is suitably in the range of 1 to 40 μm, preferably in the range of 2 to 30 μm, as the wet film thickness.

  As a dry film thickness, it is 1 micrometer or more, Preferably it is the range of 1-10 micrometers. When the dry film thickness is 1 μm or more, the above-mentioned localized phase is easily formed, and excellent mechanical strength can be obtained. In addition to the above components, the functional composition may contain the following compounds.

(Other compounds: polymerization initiator)
A polymerization initiator may be added to accelerate the curing of the resin material. Examples of the polymerization initiator include a compound that thermally generates active radical species (thermal polymerization initiator) and a compound that generates active radical species by radiation (light) irradiation (radiation (light) radical polymerization initiator). Can do. Moreover, the compound (radiation (light) acid generator) etc. which generate | occur | produce an acid by irradiation with an acidic compound and radiation (light) can also be mentioned. Among these, a radiation (photo) polymerization initiator is preferable.

  The radiation (photo) radical polymerization initiator is not particularly limited as long as it can be decomposed by light irradiation to generate radicals to initiate polymerization. For example, acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone 2,2-dimethoxy-1,2-diphenylethane-1-one, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxy Benzophenone, 4,4'-diaminobenzophenone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-o 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2- Morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) and the like. Examples of commercially available radiation (photo) radical polymerization initiators include Irgacure 184, 369, 651, 500, 819, 907, 784, 2959, CGI 1700, CGI 1750, CGI 1850, CG 24-61, etc., manufactured by BASF Japan. It is done.

  The thermal radical polymerization initiator is not particularly limited as long as it is decomposed by heating to generate radicals to initiate polymerization, and examples thereof include peroxides and azo compounds. Specific examples include: Examples include benzoyl peroxide, t-butyl-peroxybenzoate, and azobisisobutyronitrile.

As the radiation (photo) acid generator, compounds of triarylsulfonium salts and diaryliodonium salts can be used. Examples of commercially available radiation (light) acid generators include CPI-100P and 101A manufactured by San Apro.
In the functional composition, the polymerization initiator is preferably in the range of 0.01 to 20% by mass, more preferably 0.1 to 10% by mass, when the total of components excluding the solvent is 100% by mass. It is a range. When it is in the range of 0.01 to 20% by mass, the hardness when cured is sufficient, and the hardness of the coating film is not impaired. In addition, a polymerization initiator may use a multiple types of compound together.

(Other compounds: Conductive agent)
The functional layer may contain a conductive agent in order to impart antistatic properties. Preferred conductive agents include π-conjugated conductive polymers and ionic liquids.

(Other compounds: additives)
The functional layer may contain an additive such as a silicone surfactant, a fluorine surfactant, an anionic surfactant, and a fluorine-siloxane graft compound, a fluorine compound, and an acrylic copolymer. Moreover, you may contain the compound whose HLB value is 3-18. The HLB value is Hydrophile-Lipophile-Balance, hydrophilic-lipophilic-balance, and is a value indicating the hydrophilicity or lipophilicity of a compound. The smaller the HLB value, the higher the lipophilicity, and the higher the value, the higher the hydrophilicity. The HLB value can be obtained by the following calculation formula.

HLB = 7 + 11.7Log (Mw / Mo)
In the formula, Mw represents the molecular weight of the hydrophilic group, Mo represents the molecular weight of the lipophilic group, and Mw + Mo = M (molecular weight of the compound). Alternatively, according to the Griffin method, HLB value = 20 × total formula weight of hydrophilic part / molecular weight (J. Soc. Cosmetic Chem., 5 (1954), 294) and the like. Specific examples of the compound having an HLB value of 3 to 18 are listed below, but the present invention is not limited thereto. Figures in parentheses indicate HLB values.

  Made by Kao Corporation: Emulgen 102KG (6.3), Emulgen 103 (8.1), Emulgen 104P (9.6), Emulgen 105 (9.7), Emulgen 106 (10.5), Emulgen 108 (12. 1), Emulgen 109P (13.6), Emulgen 120 (15.3), Emulgen 123P (16.9), Emulgen 147 (16.3), Emulgen 210P (10.7), Emulgen 220 (14.2) , Emulgen 306P (9.4), Emulgen 320P (13.9), Emulgen 404 (8.8), Emulgen 408 (10.0), Emulgen 409PV (12.0), Emulgen 420 (13.6), Emulgen 430 (16.2), Emulgen 705 (10.5), Emulgen 707 (12.1), Emulgen 7 9 (13.3), Emulgen 1108 (13.5), Emulgen 1118S-70 (16.4), Emulgen 1135S-70 (17.9), Emulgen 2020G-HA (13.0), Emulgen 2025G (15. 7), Emulgen LS-106 (12.5), Emulgen LS-110 (13.4), Emulgen LS-114 (14.0), manufactured by Nissin Chemical Industry Co., Ltd .: Surfynol 104E (4), Surfynol 104H (4), Surfinol 104A (4), Surfinol 104BC (4), Surfinol 104DPM (4), Surfinol 104PA (4), Surfinol 104PG-50 (4), Surfinol 104S (4), Surfi Knoll 420 (4), Surfynol 440 (8), Surfynol 46 (13), Surfinol 485 (17), Surfinol SE (6), manufactured by Shin-Etsu Chemical Co., Ltd .: X-22-4272 (7), X-22-6266 (8), KF-351 (12), KF-352 (7), KF-353 (10), KF-354L (16), KF-355A (12), KF-615A (10), KF-945 (4), KF-618 (11), KF -6011 (12), KF-6015 (4), KF-6004 (5). Examples of the silicone surfactant include polyether-modified silicone, and the KF series manufactured by Shin-Etsu Chemical Co., Ltd. can be used. Examples of the acrylic copolymer include commercially available compounds such as BYK-350 and BYK-352 manufactured by BYK Japan. Examples of the fluorosurfactant include Megafac RS series manufactured by DIC Corporation, Megafac F-444 Megafac F-556, and the like. The fluorine-siloxane graft compound refers to a compound of a copolymer obtained by grafting polysiloxane and / or organopolysiloxane containing siloxane and / or organosiloxane alone on at least a fluorine-based resin. Such a fluorine-siloxane graft compound can be prepared by a method as described in Examples described later. Or as a commercial item, Fuji Chemical Industries Ltd. ZX-022H, ZX-007C, ZX-049, ZX-047-D etc. can be mentioned. Moreover, as a fluorine-type compound, Daikin Industries Ltd. OPTOOL DSX, OPTOOL DAC, etc. can be mentioned. These additives are preferably added in the range of 0.005 parts by mass or more and 5 parts by mass or less with respect to the components excluding the solvent in the functional composition.

(Other compounds: UV absorber)
The functional layer may further contain an ultraviolet absorber described in the base film described later. The content of the ultraviolet absorber is preferably in the range of mass ratio and ultraviolet absorber: resin material = 0.01: 100 to 10: 100.

(Other compounds)
The functional layer can contain a particle dispersant, an antioxidant, a light stabilizer, a silane coupling, a thermal polymerization inhibitor, a colorant, a storage stabilizer, a plasticizer, a lubricant, and the like, if necessary. Among these, by using a compound containing a fluorine atom or a compound having a siloxane chain as a particle dispersant, it is possible to promote uneven distribution of fine particles such as hollow silica particles and to lower the refractive index of the coating film. it can.

(Method for producing functional layer)
The method for producing the functional layer includes a curable resin that is a resin material, fine particles, an organic solvent that swells or dissolves the base film, and a solvent that does not swell or dissolve the base film as necessary, a polymerization initiator, and others. A functional composition containing the additive is prepared by mixing at room temperature or under heating conditions, and the mixed functional composition is applied on the surface of the base film on which the matting agent is unevenly distributed. And curing the functional composition to form a cured film. According to such a method for producing a functional layer, the functional composition is once applied on the base film and cured, so that the side opposite to the side in contact with the base film (the thickness of the functional layer) Where L is 50% by mass or more of the fine particles contained in the functional layer in a region less than ½ L in the thickness direction from the surface opposite to the base film of the functional layer. A layer in which fine particles are present in a high density in the existing phase) is formed. Hereinafter, it demonstrates for every process.

(Coating process)
The method for applying the functional composition on the base film is not particularly limited, and examples thereof include die coating, reduced-press die coating, bar coat coating, air knife coating, gravure coating, gravure reverse coating, Known methods such as reverse roll coating, lip coating, dip coating, offset printing, flexographic printing, and screen printing can be used. Among these, die coating, reduced pressing die coating, and gravure coating are preferable.

(Curing process)
The functional composition applied on the base film is cured to form a cured film. The curing conditions are not particularly limited. Specifically, a functional layer is formed by performing a curing treatment with radiation and / or heat after drying a volatile component by drying in a range of 0 to 200 ° C., preferably 80 to 120 ° C. can do. Preferable conditions for curing with heat are in the range of 20 to 150 ° C. and in the range of 10 seconds to 24 hours. When curing with radiation, it is preferable to use ultraviolet rays or electron beams. The amount of ultraviolet irradiation is preferably in the range of 0.01 to 10 J / cm ² , and more preferably in the range of 0.1 to ² J / cm ² . Moreover, the irradiation conditions of an electron beam are the range whose pressurization voltage is 10-300 kV, the electron density is 0.02-0.30 mA / cm < ² >, and the electron beam irradiation amount is the range of 1-10 Mrad.

(Drying process)
A drying step may be provided before the curing step. As a drying process, what is necessary is just to have the function to volatilize and remove the solvent in a functional composition. As drying temperature, it is the range of 0-200 degreeC, Preferably it is the range of 80-120 degreeC.

  A solvent that swells or dissolves the base film in the functional composition applied on the base film made of the cellulose ester resin dissolves a part of the cellulose ester resin that is the base film.

  Since the dissolved cellulose ester resin is hydrophilic, the applied functional composition has increased hydrophilicity in the vicinity of the base film, and relatively hydrophobic fine particles are separated from the base film in the drying step. When the thickness of the functional layer is L by being unevenly distributed (localized) and cured in the curing process, the thickness of the functional layer from the surface opposite to the base film is ½ L in the thickness direction. It is estimated that a localized phase containing 50% by mass or more of fine particles contained in the functional layer can be obtained in a region less than the above.

(Reflectance)
The visibility reflectance of the optical film of the present invention indicates that the lower the numerical value, the better the antireflection performance. Specifically, the visibility reflectance is preferably 4.0% or less, more preferably 3.0% or less. The visibility reflectance is a value obtained by treating the back surface of the obtained optical film with black spray or the like and measuring with a spectrocolorimeter CM-3700d (manufactured by Konica Minolta).

(Haze)
The haze of the optical film is preferably in the range of 0.2 to 10% from the visibility when used in an image display device. Haze can be measured according to JIS-K7105 and JIS K7136.

(hardness)
The optical film of the present invention has a pencil hardness, which is an index of hardness, of H or higher, more preferably 2H or higher. If it is more than H, it will be hard to be damaged in the polarizing plate forming step. The pencil hardness is determined by conditioning the prepared optical film at a temperature of 23 ° C. and a relative humidity of 55% for 2 hours or more and then using a test pencil specified by JIS S 6006 under a weight of 500 g. It is the value measured according to the pencil hardness evaluation method prescribed | regulated by JISK5400. Next, the base film according to the present invention will be described.

<Base film>
The base film of the optical film according to the present invention is preferably a cellulose ester resin film from the viewpoint that the objective effect of the present invention is easily obtained. Hereinafter, the cellulose ester resin film will be described.

  Examples of the cellulose ester resin film (hereinafter also referred to as cellulose ester film or cellulose acetate film) include a triacetyl cellulose film, a cellulose acetate propionate film, a cellulose diacetate film, and a cellulose acetate butyrate film. The cellulose ester film may be used in combination with polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate resins, polyethylene resins, polypropylene resins, norbornene resins, fluororesins, and cycloolefin polymers. Examples of commercially available cellulose ester films include Konica Minoltak KC8UX, KC4UX, KC8UY, KC4UY, KC6UA, KC4UA, KC4UE, and KC4UZ (manufactured by Konica Minolta Opto, Inc.). The refractive index of the cellulose ester film is preferably 1.45 to 1.55. The refractive index can be measured according to JIS K7142-2008.

(Cellulose ester resin)
The cellulose ester resin (hereinafter also referred to as cellulose ester) is preferably a lower fatty acid ester of cellulose. The lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. For example, cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, etc. Further, mixed fatty acid esters such as cellulose acetate butyrate can be used.

  Among the above descriptions, the lower fatty acid esters of cellulose that are particularly preferably used are cellulose diacetate, cellulose triacetate, and cellulose acetate propionate. These cellulose esters can be used alone or in combination.

  Cellulose diacetate preferably has an average degree of acetylation (bound acetic acid amount) of 51.0% to 56.0%. Examples of commercially available products include L20, L30, L40, and L50 manufactured by Daicel Corporation, and Ca398-3, Ca398-6, Ca398-10, Ca398-30, and Ca394-60S manufactured by Eastman Chemical Japan Co., Ltd. .

  Cellulose triacetate preferably has an average degree of acetylation (bound acetic acid amount) in the range of 54.0 to 62.5%, and more preferably has an average degree of acetylation in the range of 58.0 to 62.5%. Cellulose triacetate.

  As the cellulose triacetate, a cellulose triacetate A having a number average molecular weight (Mn) of 125,000 or more and less than 155000, a weight average molecular weight (Mw) of 265,000 or more and less than 310,000, and Mw / Mn of 1.9 to 2.1. The degree of acetyl group substitution is 2.75 to 2.90, the number average molecular weight (Mn) is 155000 or more and less than 180000, Mw is 290000 or more and less than 360,000, and Mw / Mn is in the range of 1.8 to 2.0. It is preferable to contain a certain cellulose triacetate B.

  Cellulose acetate propionate has an acyl group having 2 to 4 carbon atoms as a substituent. When the substitution degree of acetyl group is X and the substitution degree of propionyl group or butyryl group is Y, the following formula (I ) And (II) are preferably satisfied at the same time.

Formula (I) 2.6 ≦ X + Y ≦ 3.0
Formula (II) 0 ≦ X ≦ 2.5
Among them, it is preferable that 1.9 ≦ X ≦ 2.5 and 0.1 ≦ Y ≦ 0.9.

  The method for measuring the substitution degree of the acyl group can be measured according to ASTM-D817-96.

  The number average molecular weight (Mn) and molecular weight distribution (Mw) of the cellulose ester can be measured using high performance liquid chromatography. The measurement conditions are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803G
(Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (GL Science Co., Ltd.)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corp.) Mw = 100000 to 500 samples were used. The 13 samples are preferably used at approximately equal intervals.

(Thermoplastic acrylic resin)
The cellulose ester film may be used in combination with a thermoplastic acrylic resin. When used in combination, the mass ratio of the thermoplastic acrylic resin to the cellulose ester resin is preferably in the range of thermoplastic acrylic resin: cellulose ester resin = 95: 5 to 50:50.

  Acrylic resin also includes methacrylic resin. Although it does not restrict | limit especially as an acrylic resin, What consists of the range of 50-99 mass% of methyl methacrylate units, and the range of 1-50 mass% of other monomer units copolymerizable with this is preferable. . Other monomers that can be copolymerized include alkyl methacrylates having 2 to 18 carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, acrylic acid, methacrylic acid, and the like. Unsaturated group-containing divalent carboxylic acids such as saturated acid, maleic acid, fumaric acid and itaconic acid, aromatic vinyl compounds such as styrene and α-methylstyrene, α, β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, Maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride and the like may be mentioned, and these may be used alone or in combination of two or more.

  Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer, and methyl acrylate and n -Butyl acrylate is particularly preferably used. Moreover, it is preferable that a weight average molecular weight (Mw) is the range of 80000-500000, More preferably, it is the range of 110000-500000.

The weight average molecular weight of the acrylic resin can be measured by gel permeation chromatography. Commercially available acrylic resins include, for example, Delpet 60N, 80N (Asahi Kasei Chemicals Corporation), Dialnal BR52, BR80, BR83, BR85, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Electrochemical Industry Co., Ltd.) )) And the like. Two or more acrylic resins can be used in combination.
(Matting agent)
In order to improve the handleability, the base film according to the present invention, for example, acrylic particles, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, It contains a known matting agent such as inorganic fine particles such as aluminum silicate, magnesium silicate and calcium phosphate, and a crosslinked polymer. Among these, silicon dioxide is preferable from the viewpoint that the haze of the base film can be reduced and the surface where the matting agent is localized is easily formed. The average primary particle diameter of the matting agent is at 2 0 nm or less, more preferably in the range of 5 to 16 nm, especially preferably in the range of 5～12Nm.

  It is preferable that a base film contains the ester compound or sugar ester represented by the following general formula (X) from the dimensional stability by an environmental change. First, the ester compound represented by the general formula (X) will be described.

Formula (X) B- (GA) _n -GB
(Wherein B is a hydroxy group or carboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms) , A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.)
In the general formula (X), as the alkylene glycol component having 2 to 12 carbon atoms, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl -1,5-pentanediol 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl There are 1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like. Used as a mixture of two or more. In particular, an alkylene glycol having 2 to 12 carbon atoms is particularly preferable because of excellent compatibility with cellulose acetate. Examples of the aryl glycol component having 6 to 12 carbon atoms include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol and the like, and these glycols can be used as one kind or a mixture of two or more kinds.

  Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and the like. These glycols are one kind or two or more kinds. Can be used as a mixture. Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, and the like. Used as a mixture of two or more. Examples of the arylene dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and the like. Although the specific example (compound X-1-compound X-17) of a compound represented by general formula (X) below is shown, it is not limited to this.

  Next, the sugar ester compound will be described. The sugar ester compound is a sugar ester other than cellulose ester, and is a compound obtained by esterifying all or part of the OH group of a sugar such as the following monosaccharide, disaccharide, trisaccharide or oligosaccharide. Examples of the sugar include glucose, galactose, mannose, fructose, xylose, arabinose, lactose, sucrose, nystose, 1F-fructosyl nystose, stachyose, maltitol, lactitol, lactulose, cellobiose, maltose, cellotriose, maltotriose, raffinose And kestose. In addition, gentiobiose, gentiotriose, gentiotetraose, xylotriose, galactosyl sucrose, and the like are also included. Among these compounds, compounds having a furanose structure and / or a pyranose structure are particularly preferable. Among these, sucrose, kestose, nystose, 1F-fructosyl nystose, stachyose and the like are preferable, and sucrose is more preferable. As oligosaccharides, maltooligosaccharides, isomaltooligosaccharides, fructooligosaccharides, galactooligosaccharides, and xylo-oligosaccharides can also be preferably used.

  The monocarboxylic acid used for esterifying the sugar is not particularly limited, and known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid and the like can be used. The carboxylic acid to be used may be one kind or a mixture of two or more kinds. Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid , Saturated fatty acids such as tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, heptacosanoic acid, montanic acid, melicic acid, and laccelic acid, Examples include unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid and octenoic acid. Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof. Examples of preferred aromatic monocarboxylic acids include benzoic acid, aromatic monocarboxylic acids having an alkyl group or alkoxy group introduced into the benzene ring of benzoic acid, cinnamic acid, benzylic acid, biphenylcarboxylic acid, naphthalenecarboxylic acid, tetralin An aromatic monocarboxylic acid having two or more benzene rings such as carboxylic acid, or a derivative thereof can be mentioned, and more specifically, xylic acid, hemelic acid, mesitylene acid, planicylic acid, γ-isojurylic acid, Julylic acid, mesitic acid, α-isoduric acid, cumic acid, α-toluic acid, hydroatropic acid, atropic acid, hydrocinnamic acid, salicylic acid, o-, m, p-anisic acid, creosote acid, o-, m, p-homosalicylic acid, o-pyrocatechuic acid, β-resorcylic acid, vanillic acid, isovanillic acid, veratrum acid o- veratric acid, gallic acid, asarone acid, mandelic acid, homoanisic acid, homovanillic acid, homoveratric acid, o- homoveratric acid, Futaron acid, can be mentioned p- coumaric acid, especially benzoic acid. Among the ester compounds esterified, an acetyl compound into which an acetyl group has been introduced by esterification is preferable. Although the specific example of the sugar ester compound which can be used for this invention below is shown, it is not limited to these.

  The sugar ester compound is preferably a compound represented by the general formula (Y). Below, the compound shown by general formula (Y) is demonstrated.

(Wherein R _{1 to} R ₈ represent a hydrogen atom, a substituted or unsubstituted alkylcarbonyl group having 2 to 22 carbon atoms, or a substituted or unsubstituted arylcarbonyl group having 2 to 22 carbon atoms; R ₁ to R ₈ may be the same or different.)
Although the compound shown with general formula (Y) below is shown more concretely (compound Y-1-compound Y-23), it is not limited to these. In the following table, when the average degree of substitution is less than 8.0, any one of R _{1 to} R ₈ represents a hydrogen atom.

  The substitution degree distribution can be adjusted to the desired substitution degree by adjusting the esterification reaction time or mixing compounds having different substitution degrees.

  The ester compound or sugar ester compound represented by the general formula (X) is preferably contained in the base film in the range of 1 to 30% by mass, more preferably in the range of 5 to 25% by mass. It is particularly preferable to contain ~ 20% by mass.

(Other additives)
[Plasticizer]
The base film according to the present invention may contain a plasticizer as necessary. The plasticizer is not particularly limited, but is a polyvalent carboxylic ester plasticizer, glycolate plasticizer, phthalate ester plasticizer, phosphate ester plasticizer, and polyhydric alcohol ester plasticizer, acrylic. A plasticizer etc. are mentioned. In these, an acrylic plasticizer is preferable from the point which can control a cellulose-ester film to the retardation value mentioned later.

  The polyhydric alcohol ester plasticizer is a plasticizer comprising an ester of a divalent or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule. Preferably it is a 2-20 valent aliphatic polyhydric alcohol ester. Specific examples of the polyhydric alcohol ester plasticizer are shown below, but are not limited thereto.

  The glycolate plasticizer is not particularly limited, but alkylphthalylalkyl glycolates can be preferably used. Examples of alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl ethyl Glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl glycol Butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalyl methyl glycolate, octyl phthalate Ethyl glycolate, and the like.

  Examples of the phthalate ester plasticizer include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, and dicyclohexyl terephthalate.

  Examples of the phosphate ester plasticizer include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate and the like.

  The polyvalent carboxylic acid ester plasticizer is a compound composed of an ester of a divalent or higher valent, preferably a divalent to -20 valent polyvalent carboxylic acid and an alcohol. Specific examples include triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyl triphenyl citrate, acetyl tribenzyl citrate, dibutyl tartrate, tartaric acid Examples include, but are not limited to, diacetyldibutyl, tributyl trimellitic acid, tetrabutyl pyromellitic acid, and the like.

  The acrylic plasticizer is preferably an acrylic polymer, and the acrylic polymer is preferably a homopolymer or copolymer of acrylic acid or alkyl methacrylate. Examples of the acrylate monomer include methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-), pentyl acrylate ( n-, i-, s-), hexyl acrylate (n-, i-), heptyl acrylate (n-, i-), octyl acrylate (n-, i-), nonyl acrylate (n-, i-), myristyl acrylate (n-, i-), acrylic acid (2-ethylhexyl), acrylic acid (ε-caprolactone), acrylic acid (2-hydroxyethyl), acrylic acid (2-hydroxypropyl), acrylic Acid (3-hydroxypropyl), acrylic acid (4-hydroxybutyl), acrylic acid (2-hydroxybutyl), acrylic acid (2-methoxyethyl), acrylic acid 2-ethoxyethyl), etc., or the acrylic acid ester may include those obtained by changing the methacrylic acid ester. The acrylic polymer is a homopolymer or copolymer of the above-mentioned monomers, but the acrylic acid methyl ester monomer unit preferably has 30% by mass or more, and the methacrylic acid methyl ester monomer unit has 40% by mass or more. preferable. In particular, a homopolymer of methyl acrylate or methyl methacrylate is preferred.

  In addition, when it contains the plasticizer mentioned above, it is preferable to make the usage-amount contain in the range of 1-50 mass% with respect to a cellulose acetate, for example, and it is more preferable to make it contain in the range of 5-35 mass%, It is especially preferable to make it contain in 25 mass%.

(UV absorber)
The base film according to the present invention may contain an ultraviolet absorber. Since the ultraviolet absorber absorbs ultraviolet rays of 400 nm or less, durability can be improved. In particular, the ultraviolet absorber preferably has a transmittance of 10% or less at a wavelength of 370 nm, more preferably 5% or less, and still more preferably 2% or less. Specific examples of the ultraviolet absorber are not particularly limited. For example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex salts, inorganic powders. Examples include the body.

  More specifically, for example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxylphenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6 -(Linear and side chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone, etc. can be used. Commercially available products may be used. For example, TINUVIN such as TINUVIN 109, TINUVIN 171, TINUVIN 234, TINUVIN 326, TINUVIN 327, and TINUVIN 328 manufactured by BASF Japan Ltd. can be preferably used.

  Preferred ultraviolet absorbers are benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, and triazine ultraviolet absorbers, and particularly preferred are benzotriazole ultraviolet absorbers and benzophenone ultraviolet absorbers.

In addition, a discotic compound such as a compound having a 1,3,5 triazine ring is also preferably used as the ultraviolet absorber. As the UV absorber, a polymer UV absorber can be preferably used, and a polymer type UV absorber is particularly preferably used.
As a benzotriazole ultraviolet absorber, TINUVIN 109 (octyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazole-2-) manufactured by BASF Japan Ltd., which is a commercial product, is available. Yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate), TINUVIN 928 (2 -(2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol) and the like can be used. As the triazine-based ultraviolet absorber, TINUVIN 400 (2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -manufactured by BASF Japan Ltd., which is a commercial product, is available. Reaction product of 5-hydroxyphenyl and oxirane), TINUVIN 460 (2,4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3-5 Triazine), TINUVIN 405 (2- (2,4-dihydroxyphenyl) -4,6-bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidic acid ester Reaction products) and the like.

  The ultraviolet absorber is added by dissolving the ultraviolet absorber in an alcohol such as methanol, ethanol, butanol or the like, an organic solvent such as methylene chloride, methyl acetate, acetone, dioxolane, or a mixed solvent thereof, and then becomes a base film. It may be added to the resin solution (dope) or directly during the dope composition. For an inorganic powder that does not dissolve in an organic solvent, a dissolver or a sand mill is used in the organic solvent and cellulose acetate to disperse and then added to the dope.

  The amount of the ultraviolet absorber used is preferably in the range of 0.5 to 10% by mass, more preferably in the range of 0.6 to 4% by mass with respect to the base film.

(Antioxidant)
The base film according to the present invention may further contain an antioxidant (deterioration inhibitor). As the antioxidant, hindered phenol compounds are preferably used. For example, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl). -4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3 5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- 3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 1,3 5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate Etc. The addition amount of these compounds is preferably in the range of 1 to 10000 ppm, more preferably in the range of 10 to 1000 ppm by mass ratio with respect to the base film.

(Disadvantage)
The substrate film preferably has a defect of 5 μm or more in diameter of 1 piece / 10 cm square or less. More preferably, it is 0.5 piece / 10 cm square or less, more preferably 0.1 piece / 10 cm square or less. Here, the diameter of the defect indicates the diameter when the defect is circular, and when the defect is not circular, the range of the defect is determined by observing with a microscope by the following method, and the maximum diameter (diameter of circumscribed circle) is determined.

  The range of the defect is the size of the shadow when the defect is observed with the transmitted light of the differential interference microscope when the defect is a bubble or a foreign object. When the defect is a change in the surface shape such as transfer of a roller scratch or an abrasion, the size can be confirmed by observing the defect with the reflected light of a differential interference microscope.

  When the number of defects is greater than 1/10 cm square, for example, when the film is tensioned during processing in a later process, the film may break with the defects as a starting point, and productivity may decrease. Moreover, when the diameter of a defect becomes 5 micrometers or more, it can confirm visually by polarizing plate observation etc., and when used as an optical member, a bright spot may arise.

  Moreover, even when it cannot be visually confirmed, when a functional layer is formed, a coating film cannot be formed uniformly, resulting in a defect (missing coating). Here, the defect is a void in the film (foaming defect) generated due to the rapid evaporation of the solvent in the drying process of the solution casting, a foreign matter in the film forming stock solution, or a foreign matter mixed in the film forming. This refers to foreign matter (foreign matter defect) in the film. In addition, the base film preferably has a breaking elongation of at least one direction of 10% or more, more preferably 20% or more, in the measurement based on JIS-K7127-1999. The upper limit of the elongation at break is not particularly limited, but is practically about 250%. In order to increase the elongation at break, it is effective to suppress defects in the film caused by foreign matter and foaming.

(optical properties)
The base film preferably has a total light transmittance of 90% or more, more preferably 92% or more. Moreover, as a realistic upper limit, it is about 99%. The haze value is preferably 10% or less, more preferably 2% or less. The total light transmittance and haze value can be measured according to JIS K7361 and JIS K7136.

  The in-plane retardation value Ro of the base film is preferably in the range of 0 to 20 nm, and the retardation value Rth in the thickness direction is preferably in the range of −100 to 100 nm. Further, Rth is more preferably in the range of −50 to 50 nm.

  Ro and Rth are values defined by the following formulas (i) and (ii).

Formula _{(i) Ro = (n x} -n y) × d
Formula (ii) Rth = {(n _x + _ny ) / 2−n _z } × d
(Wherein, n _x is a refractive index in a slow axis direction in the substrate film surface, n _y is the refractive index in the direction perpendicular to the slow axis in the base film surface, the thickness of the n _z is a substrate film (The refractive index in the direction, d represents the thickness (nm) of the substrate film, respectively.)
The retardation can be determined at a wavelength of 590 nm in an environment of 23 ° C. and 55% RH (relative humidity) using, for example, KOBRA-21ADH (manufactured by Oji Scientific Instruments). Use of the base film controlled to the retardation value is preferable from the viewpoint of excellent visibility when used in an image display device such as a touch panel or a liquid crystal display device. Retardation can be adjusted by the kind and addition amount of a plasticizer mentioned above, the film thickness of a base film, stretching conditions, and the like.

(Method for forming base film)
Next, although the example of the film forming method of a base film is demonstrated, it is not limited to this. As a method for forming a cellulose ester film, a production method such as an inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, or a hot press method can be used. The casting method is preferred from the viewpoint of easy formation.

(Organic solvent)
In addition, organic solvents useful for forming a resin solution (dope) when a base film is produced by a solution casting method are those that simultaneously dissolve resins such as cellulose ester resins and other additives. If it is, it can be used without limitation. For example, as the chlorinated organic solvent, methylene chloride, as the non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol, etc. Can, methylene chloride, methyl acetate, ethyl acetate, may be used preferably acetone. The solvent is preferably a dope in which a total of 15 to 45% by mass of cellulose ester resin, matting agent, plasticizer and other additives are dissolved.

[Solution casting film forming method]
In the solution casting film forming method, a step of preparing a dope in which a resin, a matting agent and an additive are dissolved in a solvent, a step of casting the dope on a belt-like or drum-like metal support, and a cast dope It is performed by a step of drying as a web, a step of peeling from a metal support, a step of stretching or maintaining the width, a step of further drying, and a step of winding up the finished cellulose ester film.

  As the metal support, a stainless steel belt or a drum whose surface is plated with a casting is preferably used.

  By forming the base film according to the present invention by a solution casting film forming method in which a dope is cast on a belt-like metal support, the drying speed of the dope is different on the belt surface side and the air surface side. The base film having a surface on which the matting agent is localized (air surface side) and a surface on which the plasticizer is localized (belt surface side) is obtained depending on the specific gravity of the components in the dope. As the film forming method, a solution casting film forming method using belt film forming is preferable. By applying the functional layer according to the present invention to the matting agent localizing surface using the base film produced using the film forming method, the elastic modulus of the base film is reduced or the mixed layer region is used. It is preferable because the reaction can be suppressed and excellent curling characteristics and flexibility can be obtained after the durability test.

  In addition to the method of taking and analyzing tomographic images of the substrate film with the transmission electron microscope described above, the confirmation of the localized state of the matting agent and plasticizer of the substrate film is also possible with the time-of-flight secondary ion mass for each surface. It can also be confirmed by analyzing with an analyzer (TOF-SIMS) or an X-ray photoelectron analyzer (ESCA).

  Here, time-of-flight secondary ion mass spectrometry can measure the chemical information of atoms and molecules on a solid sample with a sensitivity of one molecular layer or less, and the distribution of specific atoms and molecules with a spatial resolution of 100 nm or less. This is an observable mass spectrometry method. Time-of-flight secondary ion mass spectrometry is a type of secondary ion mass spectrometry (SIMS), in which a solid sample is irradiated with a primary ion beam, and ions emitted from the outermost surface of the sample (two Analysis is performed by detecting (secondary ions). Since a time-of-flight mass spectrometer (TOF-MS) is used as the mass spectrometer, it is referred to as TOF-SIMS.

  According to time-of-flight secondary ion mass spectrometry, it is possible to measure a sample substantially non-destructively by irradiating the sample with an ion beam in a pulsed manner. It has been widely applied to the analysis of

  The width of the base film cast is preferably in the range of 1 to 4 m. The surface temperature of the metal support in the casting step is set in a range of −50 ° C. to a temperature at which the solvent boils and does not foam. A higher temperature is preferred because the web can be dried faster, but if it is too high, the web may foam or the flatness may deteriorate.

  A preferable support temperature is appropriately determined in the range of 0 to 100 ° C, and more preferably in the range of 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing warm air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short.

  When using warm air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the intended temperature is used while preventing foam .

  In particular, it is preferable to perform drying efficiently by changing the temperature of the support and the temperature of the drying air during the period from casting to peeling.

  In order for the base film to obtain good flatness, the amount of residual solvent when peeling the web from the metal support is preferably in the range of 10 to 150% by mass, more preferably 20 to 40% by mass. The range or the range of 60 to 130% by mass, particularly preferably the range of 20 to 30% by mass or the range of 70 to 120% by mass. The amount of residual solvent is defined by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Note that M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.

  Further, in the drying process of the base film, the web is peeled off from the metal support and dried, and the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less, particularly preferably. It is the range of 0-0.01 mass%.

  In the film drying step, generally, a roller drying method (a method in which webs are alternately passed through a plurality of rollers arranged above and below) and a method in which the web is dried while being conveyed by a tenter method are employed.

  A preferable support temperature is appropriately determined in the range of 0 to 100 ° C, and more preferably in the range of 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing warm air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short.

  When using warm air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the intended temperature is used while preventing foam .

  In particular, it is preferable to perform drying efficiently by changing the temperature of the support and the temperature of the drying air during the period from casting to peeling.

  In the stretching step, the film can be sequentially or simultaneously stretched in the longitudinal direction (MD direction) and the width direction (TD direction) of the film. It is preferable that the draw ratios in the biaxial directions orthogonal to each other are finally in the range of 1.0 to 2.0 times in the MD direction and in the range of 1.05 to 2.0 times in the TD direction. It is preferable to carry out in the range of 1.0 to 1.5 times in the MD direction and in the range of 1.05 to 2.0 times in the TD direction. For example, a method of making a difference in peripheral speed between a plurality of rollers and stretching in the MD direction using the difference in peripheral speed of the roller between them, fixing both ends of the web with clips and pins, and widening the interval between the clips and pins in the traveling direction And a method of stretching in the MD direction, a method of stretching in the transverse direction and stretching in the TD direction, a method of stretching the MD direction and the TD direction at the same time, and stretching in both directions.

  These width maintenance or width direction stretching in the film forming process is preferably performed by a tenter, and may be a pin tenter or a clip tenter.

  The film transport tension in the film forming process such as a tenter depends on the temperature, but is preferably in the range of 120 to 200 N / m, and more preferably in the range of 140 to 200 N / m. A range of 140 to 160 N / m is most preferred.

  When the glass transition temperature of the base film is Tg, the temperature during stretching is in the range of (Tg-30) to (Tg + 100) ° C., more preferably in the range of (Tg-20) to (Tg + 80) ° C., and more preferably ( The range is from Tg-5) to (Tg + 20) ° C.

  The Tg of the base film can be controlled by the material type constituting the film and the ratio of the constituting materials. The Tg at the time of drying the base film is preferably 110 ° C. or higher, more preferably 120 ° C. or higher. Especially preferably, it is 150 degreeC or more. The glass transition temperature is preferably 190 ° C. or lower, more preferably 170 ° C. or lower. The Tg of the base film can be determined by the method described in JIS K7121. The stretching temperature is preferably 150 ° C. or more and the stretching ratio is 1.15 times or more because the surface is appropriately roughened. Roughening the surface of the base film is preferable because it improves slipperiness and improves surface processability.

[Melt casting method]
The base film may be formed by a melt casting film forming method. In the melt casting film forming method, a composition containing other additives such as a resin and a plasticizer is heated and melted to a temperature showing fluidity, and then a melt containing a fluid cellulose ester is cast. Say.

  In the melt casting film forming method, the melt extrusion method is preferable from the viewpoint of mechanical strength and surface accuracy. A plurality of raw materials used for melt extrusion are usually preferably kneaded and pelletized in advance.

  Pelletization may be performed by a known method. For example, dry cellulose ester, plasticizer, and other additives are fed to an extruder with a feeder and kneaded using a single-screw or twin-screw extruder, and formed into a strand from a die. It can be done by extrusion, water cooling or air cooling and cutting.

  The additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders.

  A small amount of additives such as particles and antioxidants are preferably mixed in advance in order to mix uniformly.

  The extruder is preferably processed at a temperature as low as possible so that it can be pelletized so that the shearing force is suppressed and the resin does not deteriorate (molecular weight reduction, coloring, gel formation, etc.). For example, in the case of a twin screw extruder, it is preferable to rotate in the same direction using a deep groove type screw. From the uniformity of kneading, the meshing type is preferable.

  A film is formed using the pellets obtained as described above. Of course, the raw material powder can be directly fed to the extruder by a feeder without being pelletized to form a film as it is.

  Using a single or twin screw extruder, the pellets are melted at a temperature of about 200 to 300 ° C., filtered through a leaf disk type filter or the like to remove foreign matter, and then formed into a film from a T die. Then, the film is nipped between the cooling roller and the elastic touch roller, and solidified on the cooling roller to form a substrate film.

  Moreover, it is preferable that the base film obtained as described above is further stretched after passing through the step of contacting the cooling roller.

  As the stretching method, a known roller stretching machine or tenter can be preferably used. The stretching temperature is preferably carried out in the temperature range of Tg to (Tg + 60) ° C. of the resin that usually constitutes the film.

  Prior to winding, the ends may be slit and cut to the width of the product, and knurling (embossing) may be applied to both ends to prevent sticking or scratching during winding. The knurling method can be performed by heating or pressurizing using a metal ring having an uneven pattern on the side surface. Since the base film is deformed and cannot be used as a product, the clip holding portions at both ends of the film are usually cut out and reused.

(Physical properties of film)
The film thickness of the substrate film according to the present invention is preferably in the range of 5 to 100 μm, more preferably in the range of 5 to 40 μm. In the thin film region as described above, the curl reduction effect after the durability test is particularly easily exhibited.

  The length of the base film is preferably in the range of 500 to 10000 m, more preferably in the range of 1000 to 8000 m. By setting it as the range of the said length, it is excellent in the processability in application | coating of a functional layer etc., and the handleability of the base film itself.

  The arithmetic average roughness Ra of the substrate film is preferably in the range of 2 to 10 nm, more preferably in the range of 2 to 5 nm. The arithmetic average roughness Ra can be measured according to JIS B0601: 1994.

<Polarizing plate>
A polarizing plate using the optical film of the present invention will be described. The polarizing plate can be produced by a general method. For example, the optical film of the present invention is subjected to alkali saponification treatment, and the treated optical film is bonded to at least one surface of a polarizing film produced by immersing and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Is preferred.

  The other side is KC8UX, KC4UX, KC4UY, KC8UA, KC6UA, KC4UA, KC4UE, KC4CZ, KC8UCR, KC4FR (manufactured by Konica Minolta Opto), Arton Film (JSR) Zeonor Film (manufactured by Nippon Zeon Co., Ltd.) and the like can be used.

  The polarizing film, which is the main component of the polarizing plate, is an element that transmits only light having a polarization plane in a certain direction. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film. There are those in which iodine is dyed on a system film and those in which dichroic dye is dyed, but it is not limited to this.

  As the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxial stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound. The thickness of the polarizing film is 5 to 30 μm, preferably 8 to 15 μm.

  On the surface of the polarizing film, one side of the optical film according to the present invention is bonded to form a polarizing plate. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.

(Adhesive layer)
The pressure-sensitive adhesive layer used on one side of the film to be bonded to the substrate of the liquid crystal cell is preferably optically transparent and exhibits moderate viscoelasticity and adhesive properties.

  Specific examples of the adhesive layer include adhesives or adhesives such as acrylic copolymers, epoxy resins, polyurethanes, silicone polymers, polyethers, butyral resins, polyamide resins, polyvinyl alcohol resins, and synthetic rubbers. A film such as a drying method, a chemical curing method, a thermal curing method, a thermal melting method, a photocuring method, or the like can be formed and cured using a polymer such as the above. Among them, the acrylic copolymer can be preferably used because it is most easy to control the physical properties of the adhesive and is excellent in transparency, weather resistance, durability and the like.

<Image display device>
The optical film of this invention is preferable at the point by which the performance excellent in visibility and nonuniformity is exhibited by using it for an image display apparatus. As an image display device, a reflection type, a transmission type, a transflective type liquid crystal display device, a liquid crystal display device of various drive systems such as a TN type, STN type, OCB type, VA type, IPS type, ECB type, etc., a touch panel display device And organic EL display devices and plasma displays. Among these image display devices, when the optical film of the present invention is used for a liquid crystal display device or a touch panel display device, it is preferable in view of particularly excellent visibility and unevenness.

<Touch panel>
The optical film of the present invention can be used, for example, in an inner touch panel or a capacitive touch panel using a touch panel member under the upper surface side polarizing plate of a liquid crystal display device (upper surface side polarizing plate / liquid crystal cell / lower surface side polarizing plate configuration). Can also be used.

<Glass scattering prevention film for image display device>
Next, a glass scattering prevention film for an image display device using the optical film of the present invention will be described. FIG. 2 shows an example of a schematic sectional view in which the glass scattering prevention film for an image display device using the optical film of the present invention is used in the image display device.
The image display device 30 includes an image display panel 31, a conductive glass substrate 33 disposed on the display unit (display surface) of the image display panel 31 via an adhesive layer 32, and a conductive glass substrate 33. It is comprised roughly from the glass scattering prevention film 41 for image display apparatuses stuck.
The conductive glass substrate 33 includes a glass substrate 34 and a conductive film 35.
The glass scattering prevention film 41 for an image display device is adhered to the glass substrate 34 with an adhesive layer 43.

  The glass scattering prevention film 41 for an image display device comprising the optical film 42 of the present invention has high adhesiveness with an adhesive or the like and does not need to be subjected to an easy adhesion treatment. Moreover, sufficient scattering prevention property can be obtained for the glass scattering prevention film. Further, deformation and the like hardly occur after the durability test, and the visibility is excellent.

The optical film 42 preferably has a refractive index in the range of 1.45 to 1.55 at a wavelength of 589 nm measured according to JIS K7142-2008. The pressure-sensitive adhesive layer 43 also preferably has a refractive index of 1.40 to 1.55 at a wavelength of 589 nm measured in accordance with JIS K7142-2008, more preferably 1.45 to 1.52.
The refractive index of the pressure-sensitive adhesive layer 43 can be adjusted by, for example, a method of increasing the refractive index by including an aromatic ring or a method of decreasing the refractive index by including a fluorine atom.
By setting the refractive index of the pressure-sensitive adhesive layer 43 and the glass scattering prevention film 41 for an image display device within the above range, the refractive index when bonded to a glass substrate or the like is small, and the interference fringes are excellent.

  The thickness of the pressure-sensitive adhesive layer is preferably in the range of 5 to 30 μm, and more preferably in the range of 10 to 25 μm. As an adhesive which comprises an adhesive layer, an acrylic adhesive, a silicone adhesive, a urethane adhesive, a rubber adhesive, a polyester adhesive, etc. are mentioned. These pressure-sensitive adhesives may be emulsion type, solvent type, or solventless type. Among these pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferable from the viewpoints of easy adhesion control and weather resistance. The acrylic pressure-sensitive adhesive is preferably a cross-linked acrylic resin having a weight average molecular weight in the range of 500 to 2,000,000, preferably in the range of 7,000 to 1,700,000. When the weight average molecular weight is in the above range, a film for preventing scattering can be obtained in which the adhesive force and the holding force are balanced. The aforementioned weight average molecular weight is a value in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

  As the acrylic resin contained in the acrylic pressure-sensitive adhesive, a (meth) acrylic ester copolymer is used. As this (meth) acrylic acid ester copolymer, the (meth) acrylic acid ester having 1 to 20 carbon atoms in the alkyl group of the ester portion, a monomer having a functional group having active hydrogen, and, if desired, Copolymers with other monomers used are preferred. Examples of the (meth) acrylic acid ester having 1 to 20 carbon atoms in the alkyl group of the ester moiety include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, Examples include isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) acrylate. These may be used alone or in combination of two or more. Examples of the monomer having a functional group having active hydrogen include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth). (Meth) acrylic acid hydroxyalkyl esters such as acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylol Acrylamides such as acrylamide and N-methylolmethacrylamide, monoalkylaminoalkyl (meth) acrylates such as methylaminoethyl (meth) acrylate and monoethylaminoethyl (meth) acrylate, Le acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, ethylenically unsaturated carboxylic acids such as citraconic acid. These may be used alone or in combination of two or more.

  In the acrylic pressure-sensitive adhesive, the (meth) acrylic acid ester copolymer used as a resin component may be any of random, block, and graft copolymers with respect to the copolymerization form. As the crosslinking agent used for the crosslinking treatment, a polyisocyanate compound or an epoxy compound is preferably used. A crosslinking agent may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, although the usage-amount is based also on the kind of crosslinking agent, it is 0.01-20 mass parts normally with respect to 100 mass parts of said (meth) acrylic acid ester-type copolymer solid content, Preferably, 0.1-10 It is the range of mass parts. A tackifier, antioxidant, ultraviolet absorber, light stabilizer, softener, silane coupling agent, filler and the like can be added to the acrylic pressure-sensitive adhesive. Furthermore, a protective film and a release sheet may be attached to the pressure-sensitive adhesive layer 42. Examples of the base material of the release sheet include polyethylene terephthalate, polyethylene, and polypropylene film. In order to make the surface of the release sheet substrate have release properties, a release agent such as a fluorine resin, a silicone resin, or a long-chain alkyl group-containing carbamate is attached to the surface by coating. The thickness of the release sheet substrate is preferably in the range of 5 to 300 μm, more preferably in the range of 10 to 200 μm.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
(Preparation of cellulose ester film 1)
-Preparation of silicon dioxide dispersion Aerosil R812 (manufactured by Nippon Aerosil Co., Ltd., average diameter of primary particles 7 nm)
10 parts by mass Ethanol 90 parts by mass The above was stirred and mixed with a dissolver for 30 minutes, and then dispersed with Manton Gorin. 88 parts by mass of methylene chloride was added to the silicon dioxide dispersion while stirring, and the mixture was stirred and mixed for 30 minutes with a dissolver to prepare a silicon dioxide dispersion dilution. It filtered with the fine particle dispersion | distribution dilution liquid filter (Advantech Toyo Co., Ltd .: Polypropylene wind cartridge filter TCW-PPS-1N).

<Preparation of dope 1>
(Cellulose ester resin)
Cellulose triacetate A (cellulose triacetate synthesized from linter cotton,
Acetyl group substitution degree 2.88, Mn = 14000) 90 parts by mass (additive)
X-1 5 parts by mass X-12 4 parts by mass (UV absorber)
TINUVIN 928 (manufactured by BASF Japan Ltd.) 3 parts by mass (fine particles)
Silicon dioxide dispersion dilution 4 parts by mass (solvent)
Methylene chloride 432 parts by mass Ethanol 38 parts by mass The above was put into a sealed container, heated and stirred, and dissolved completely. Azumi filter paper No. Azumi filter paper No. 24 was used to prepare a dope (Dope 1).

  Next, it cast | flow_spreaded uniformly on the stainless steel band support body using the belt casting film forming apparatus. With the stainless steel band support, the solvent was evaporated until the residual solvent amount reached 100%, and the stainless steel band support was peeled off. The cellulose ester film web was evaporated at 35 ° C., slit to 1.15 m width, and dried at a drying temperature of 160 ° C. while stretching 1.2 times in the TD direction (film width direction) with a tenter. I let you. Then, after drying for 15 minutes while transporting the inside of a drying device at 130 ° C. with many rollers, slitting to a width of 1.3 m, applying a knurling process with a width of 10 mm and a height of 5 μm on both ends of the film, and winding it around a winding core The cellulose ester film 1 was obtained. The film thickness of the cellulose ester film 1 was 40 μm, and the winding length was 5000 m. In addition, the draw ratio of MD direction computed from the rotational speed of a stainless steel band support body and the driving speed of a tenter was 1.01 times.

  The cellulose ester film 1 was prepared using a microtome to prepare an ultrathin slice sample for electron microscope observation, and then the cross section of the cellulose ester film 1 was observed with a transmission electron microscope as follows.

  After taking a tomographic photograph of the cellulose ester film 1 with a transmission electron microscope, both the air surface side and the belt surface side of the cellulose ester film 1 have a thickness of 2 μm and a width of 25 μm inward from the side in contact with air. The number of matting agents was observed.

  As a result, the number of matting agents was 1.1 times greater on the air surface side than on the belt surface side, and in the case of the cellulose ester film 1, it was confirmed that the matting agent was localized on the air surface side.

  Moreover, about the air surface side and belt surface side of the obtained cellulose-ester film 1, it analyzed using the TOF-SIMS analyzer. As a result of TOF-SIMS analysis, it was confirmed that the matting agent was localized on the air surface side.

  The TOF-SIMS analysis was performed under the following measurement conditions.

Measuring apparatus: 2100TRIFT2 (manufactured by Physical Electronics)
Measurement mode: Cooling measurement (temperature range -95 to -105 ° C)
Primary ion: Ga (15 kV)
Measurement area: 60 μm square Integration time: 2 minutes Measurement and analysis were performed with WIN-Cadence Ver4.0.14 manufactured by Physical Electronics.

(Production of cellulose ester films 2 to 5)
In producing the cellulose ester film 1, cellulose ester films 2 to 5 were produced in the same manner except that the film thickness was changed as described in Table 1.

  As a result of observing TOF-SIMS analysis of the air surface side and the belt surface side of the cellulose ester films 2 to 5 and tomographic photographs by a transmission electron microscope, the matting agent was also localized on the air surface side of the cellulose ester films 2 to 5. Confirmed that.

(Production of cellulose ester films 6-9)
In producing the cellulose ester films 1 to 5, cellulose ester films 6 to 9 were produced in the same manner except that the belt casting film forming apparatus was changed to the drum casting film forming apparatus.

  Next, as a result of observing the TOF-SIMS analysis on the air surface side and the belt surface side of the cellulose ester films 6 to 9 and the tomographic photograph by a transmission electron microscope, the plasticizer and the matting agent are uniformly mixed. It was confirmed that the matting agent was not localized on the side.

[Preparation of optical film 1]
On the air surface side (mat agent localized surface) of the produced cellulose ester film 1, the following functional composition 1 filtered through a polypropylene filter having a pore diameter of 1 μm is applied using an extrusion coater and dried. After drying at a temperature of 80 ° C., while purging with nitrogen so that the oxygen concentration is 0.2 vol% or less, the illuminance of the irradiated part is 100 mW / cm ² using an ultraviolet lamp, and the irradiation dose is 0.3 J / The coating layer was cured as cm ² to form a functional layer 1 having a dry film thickness of 3 μm, and a take-up roll-shaped optical film 1 was produced.

(Functional composition 1)
In a container shielded from ultraviolet rays, hollow silica particle dispersion 1 (solid content concentration 20% by mass, trade name “JX-1009SIV”, methyl isobutyl ketone sol, refractive index 1.36, manufactured by JGC Catalysts and Chemicals) 5 mass Parts, pentaerythritol tri / tetraacrylate (trade name “NK Ester A-TMM-3L”, refractive index 1.49, manufactured by Shin-Nakamura Chemical Co., Ltd.), 96 parts by mass, 2-methyl-1 [4- (methylthio ) Phenyl] -2-Morpholinopropan-1-one (trade name “Irgacure (registered trademark) 907”, manufactured by BASF Japan Ltd.) 3 parts by mass, Silaplane FM0725 (manufactured by Chisso Corporation) 0.1 parts by mass Further, 75 parts by mass of methyl isobutyl ketone, 20 parts by mass of cyclohexanone and 5 parts by mass of γ-butyrolactone were added and stirred at room temperature for 2 hours. To give a functional composition 1 by Rukoto.

[Preparation of optical film 2]
In the production of the optical film 1, the hollow silica particle dispersion 1 of the functional composition 1 was changed to the hollow silica particle dispersion 2 modified as follows, and the addition amount was changed to 4.4 parts by mass. Thus, an optical film 2 was produced.

(Preparation of hollow silica particle dispersion 2)
90.9 parts by mass (solid content concentration: 20% by mass) of hollow silica particles (trade name “JX-1009SIV”, methyl isobutyl ketone sol, manufactured by JGC Catalysts & Chemicals Co., Ltd.), tridecafluorooctyltrimethoxysilane (GE Toshiba Silicone) (Made by Co., Ltd.) 1 part by mass, 0.1 part by mass of isopropanol and 0.05 part by mass of ion-exchanged water were stirred at 80 ° C. for 3 hours, and then 0.7 part by mass of methyl orthoformate was added. Furthermore, a colorless and transparent hollow silica particle dispersion 2 was obtained by heating and stirring at the same temperature for 1 hour. The solid content concentration was 22.5% by mass.

[Preparation of optical films 3 to 5]
Optical films 3 to 5 were similarly produced except that the thickness of the functional layer was changed as shown in Table 1 in the production of the optical film 1.

[Preparation of optical films 6 to 14]
Optical films 6 to 14 were similarly prepared except that the cellulose ester film 1 was changed as shown in Table 1 in the production of the optical film 1.

[Production of optical films 15 and 16]
Optical films 15 and 16 were prepared in the same manner except that the application surface of the functional composition was changed to the belt surface side (non-mat agent phase) in the production of the optical film 1 and the optical film 2.

<Evaluation>
(An endurance test)
Each roll-shaped optical film packaged in aluminum was stored for 30 days under conditions of 85 ° C. and 80%, and was subjected to wet heat treatment. Next, wet heat treatment was performed.
3 m was cut from each roll of the roll-shaped optical film, and the cut optical film was conditioned for 2 hours under the conditions of a temperature of 23 ° C. and a relative humidity of 55%, and then evaluated for the following curls and flexibility.

1. Curl Measurement of the curl of each optical film after the endurance test was performed using the curl measurement template of Method A in “Measurement Method of Curling of Photographic Film” of JIS K7619-1988. Here, the curl is positive when the hard coat layer coating side of the film is on the inside of the curve, and the minus is the curl when the coating side is on the outside of the curve. Further, the curl is expressed by the following formula A.

(Formula A) Curl = 1 / R R is the radius of curvature (m)
The ranking was as follows according to the curl amount of the measurement result.
○ (excellent): minus 10 to plus 10
× (slightly inferior, practically problematic): minus 15 to minus 10 excess, plus 10 excess to plus 15
XX (Inferior): minus 15 or less, plus 15 or more Flexibility (flexibility)
Each optical film after the durability test was evaluated for flexibility (numerical diameter of the mandrel) by a cylindrical mandrel method using a type 1 test apparatus in accordance with JIS K5600-5-1. It shows that it is excellent in the flexibility, so that the numerical value of the diameter of a mandrel is low. In JIS K5600-5-1, the cylindrical mandrel has a diameter of only 2 mm, so a 1 mm diameter was prototyped.

  Next, with respect to the optical film before the durability test, the measurement of the visibility reflectance and the localized phase were observed by the following method.

3. Visibility reflectance The surface (back surface) on which the functional layer of each of the produced optical films was not coated was treated with black spray. Next, the functional layer surface was measured using a spectrocolorimeter CM-3700d (manufactured by Konica Minolta Co., Ltd.) using the optical film after black treatment, and the visibility reflectance was determined. The lower the value, the better the antireflection performance.

4). Confirmation of Localized Phase For each of the optical films prepared above, a microtome was used to prepare an ultrathin section sample for transmission electron microscope observation, and then the transmission optical microscope (Hitachi) was used at a magnification of 5000 times using the prepared optical film. A tomographic photograph was taken at Seisakusho Co., Ltd. (H-7650). From the tomogram after photographing, 500 fine particles were observed in the thickness direction of the film, and from the particle distribution, the fine particles contained in a region less than 1/2 L in the thickness direction from the surface opposite to the base film. The mass% contained was evaluated according to the following criteria to confirm the localized phase.

A: 70% by mass or more contained in a region less than 1/2 L in the thickness direction. ○: 50% by mass or more contained less than 70% by mass in a region less than 1/2 L in the thickness direction. X: No localized phase formed In the functional layer in which the localized phase was not formed, the added fine particles were uniformly dispersed in the functional layer. Further, the film thickness of the localized phase in which the fine particles are localized was measured by observation with the transmission electron microscope.

5. Comprehensive evaluation Comprehensive evaluation was performed about the optical films 1-16 based on the said evaluation result with the following references | standards.

○: Visibility reflectance 3.0% or less, curl after durability test is ○, flexibility (mandrel diameter) is 4mm or less ×: Visibility reflectance exceeds 3.0% In addition, the curl after the durability test is less than x, and the numerical value of the flexibility (mandrel diameter) exceeds 4 mm. The results obtained above are shown in Table 1.

  As can be seen from the results in Table 1, a solvent (cyclohexanone, γ-butyrolactone) that swells or dissolves the curable resin, fine particles, and the base film on the matting agent (localized) localized surface of the base film (cellulose ester film). When the functional layer containing the composition is cured and then cured to form a functional layer having a thickness of 1 μm or more, the thickness of the functional layer is L, Optics with excellent antireflection, curl and durability after endurance test by obtaining a phase in which fine particles are unevenly distributed (localized) in a region less than 1/2 L in the thickness direction from the surface on the opposite side Since a film is obtained, it turns out that it is preferable.

  In particular, the optical film of the present invention (optical films 1, 6 and 7) having a thickness of the base film in the range of 5 to 40 μm has the same thickness as the optical film of the comparative example (optical). Compared with the films 10 to 12), the curl is particularly excellent, and it can be seen that this is a particularly preferable configuration.

  About the optical films 1-16, hardness was confirmed by the pencil hardness test. Using the test pencil specified by JIS-S6006, according to the pencil hardness evaluation method specified by JIS-K5400, the hard coat layer surface of the optical films 1 to 16 is repeatedly scratched with a pencil of each hardness using a 500 g weight. As a result of measuring the hardness of up to one scratch, the pencil hardness of the optical film of the present invention was all 2H or higher.

Example 2
[Preparation of Polarizing Plate 101]
A polarizing plate 101 was prepared using the optical film 1 and the cellulose ester film 1 after the durability test.

(A) Production of Polarizing Film What was impregnated with 10 parts by mass of glycerin and 170 parts by mass of water in 100 parts by mass of polyvinyl alcohol (hereinafter abbreviated as PVA) having a saponification degree of 99.95 mol% and a polymerization degree of 2400 After melt-kneading and defoaming, the film was melt-extruded from a T die onto a metal roller to form a film. Then, it dried and heat-processed and obtained the PVA film.

  The obtained PVA film had an average thickness of 25 μm, a moisture content of 4.4%, and a film width of 3 m. Next, the obtained PVA film was continuously processed in the order of preliminary swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying, and heat treatment to prepare a polarizing film. That is, the PVA film was preliminarily swollen in water at a temperature of 30 ° C. for 30 seconds, and immersed in an aqueous solution having an iodine concentration of 0.4 g / liter and a potassium iodide concentration of 40 g / liter at a temperature of 35 ° C. for 3 minutes. Subsequently, the film was uniaxially stretched 6 times in a 50% aqueous solution with a boric acid concentration of 4% under the condition that the tension applied to the film was 700 N / m, and the potassium iodide concentration was 40 g / liter and the boric acid concentration was 40 g / liter. Then, it was immersed in an aqueous solution having a zinc chloride concentration of 10 g / liter and a temperature of 30 ° C. for 5 minutes for fixing. Thereafter, the PVA film was taken out, dried with hot air at a temperature of 40 ° C., and further heat-treated at a temperature of 100 ° C. for 5 minutes. The obtained polarizing film had an average thickness of 13 μm, a polarizing performance of a transmittance of 43.0%, a polarization degree of 99.5%, and a dichroic ratio of 40.1.

(B) Production of Polarizing Plate A polarizing plate 101 was produced by bonding the polarizing film, the cellulose ester film 1 and the optical film 1 according to the following steps 1 to 4.

  Process 1: The above-mentioned polarizing film was immersed in the storage tank of the polyvinyl alcohol adhesive agent solution of 2 mass% of solid content for 1-2 seconds.

Step 2: The optical film 1 was subjected to alkali treatment on the cellulose ester film 1 and the optical film 1 under the following conditions after pasting protective films before alkali treatment. Next, in Step 1, the polarizing film was immersed in the polyvinyl alcohol adhesive solution. Excess adhesive adhered to the immersed polarizing film was removed, and the cellulose ester film 1 and the optical film 1 were sandwiched between the polarizing films as shown in FIG. . After producing the polarizing plate, the protective film of the optical film 1 was peeled off.
(Alkali treatment)
Saponification step 3 mol / L-NaOH 50 ° C. 90 seconds Water washing step Water 30 ° C. 60 seconds Neutralization step 10 parts HCl 30 ° C. 45 seconds Water washing step Water 30 ° C. 60 seconds After saponification treatment, water washing, neutralization and water washing are performed in this order. Then dried at 100 ° C.

Step 3: The laminate was bonded at a speed of about 2 m / min at a pressure of ^{20 to} 30 N / cm ² with two rotating rollers. At this time, care was taken to prevent bubbles from entering.

  Step 4: The sample prepared in Step 3 was dried in a dryer at a temperature of 100 ° C. for 5 minutes to prepare a polarizing plate.

<Production of Polarizing Plates 102 to 116>
Polarizers 102 to 116 were produced in the same manner except that the optical film 1 was changed to the optical films 2 to 16 in the production of the polarizer 101.

<Production of Liquid Crystal Display Device 201>
(Durability test evaluation)
The produced roll-shaped polarizing plate 101 was wrapped in an aluminum moisture-proof sheet and stored for 25 days in a thermostatic bath at 50 ° C. and 80% relative humidity assuming long-term transportation. After storage for 25 days, an adhesive layer was provided as follows and then incorporated into a liquid crystal display device to produce a liquid crystal display device 201.

(Adhesive layer)
A commercially available acrylic pressure-sensitive adhesive was applied to the cellulose ester film 1 of the polarizing plate 101 so that the thickness after drying was 25 μm, dried in an oven at 110 ° C. for 5 minutes to form an adhesive layer, and then peeled off to the adhesive layer A protective film was attached.

(Liquid crystal display device 201)
Of the two pairs of polarizing plates installed on the liquid crystal display device (VS239H-P ASUS) with the liquid crystal layer sandwiched between them, the polarizing plate on one side on the viewer side is peeled off, and the polarizing plate 101 produced above is used as the functional layer. The pressure-sensitive adhesive layer and the liquid crystal cell glass were bonded together so that was on the viewing side. The liquid crystal display device 201 was manufactured by arranging the transmission axis of the polarizing plate on the viewer side and the transmission axis of the polarizing plate on the backlight side to be orthogonal to each other.

<Production of Liquid Crystal Display Devices 202 to 216>
In the production of the liquid crystal display device 201, except that the polarizing plate 101 was changed to the polarizing plates 102 to 116, respectively, after the endurance test of the polarizing plate, it was incorporated into the liquid crystal display device to produce the liquid crystal display devices 202 to 216. .

<Evaluation>
The following contents were evaluated about the produced liquid crystal display device.

a. Unevenness Evaluation Each of the liquid crystal display devices produced above was observed from the front with a black display, and unevenness was evaluated according to the following criteria.

  A: Unevenness due to deformation is not recognized at all.

  ○: Slight unevenness due to deformation is observed.

  Δ: Unevenness due to fine deformation is observed. This is a practically problematic level.

  X: Unevenness due to deformation is observed.

b. Visibility evaluation Each of the liquid crystal display devices prepared above was placed on a desk 80 cm high from the floor, and a daylight direct fluorescent lamp (FLR40S • D / MX Panasonic was placed on the ceiling 3 m high from the floor. (Made by Co., Ltd.) One set of 40W × 2 was arranged in 10 sets at 1.5 m intervals. In this case, when the evaluator is in front of the display surface of the liquid crystal display panel, the fluorescent lamp is arranged so that the fluorescent lamp comes to the ceiling portion from the evaluator's overhead to the rear. Next, each liquid crystal display panel was tilted by 25 ° from the vertical direction with respect to the desk, and the visibility (visibility) of the screen was evaluated by dividing it into the following ranks so that a fluorescent lamp was reflected.

  ○: I don't mind the reflection of fluorescent lights.

  X: Slightly worried about reflection of nearby fluorescent lamp. This is a practically problematic level.

  XX: I am worried about the reflection of fluorescent lights.

  The above evaluation results are shown in Table 2.

  As can be seen from the results in Table 2, it can be seen that a liquid crystal display device incorporating a polarizing plate produced using the optical film of the present invention is preferable because of its excellent image display performance such as unevenness and visibility.

Example 3
(Production of substrate-less adhesive sheet)
On the release surface of the release sheet (trade name: SP-PET 381031, thickness 38 μm, manufactured by Lintec Corporation), using a die coater, the pressure-sensitive adhesive-containing composition 1 was applied so that the thickness after drying was 15 μm. It dried at 120 degreeC for 2 minute (s), the adhesive layer was formed, and the base material-less adhesive sheet which consists of a peeling sheet and the adhesive layer formed in the peeling surface was obtained.
<< Adhesive-containing composition 1 >>
The following composition was stirred to prepare an adhesive-containing composition 1.
-Acrylate ester copolymer (molecular weight 800,000, concentration 35% by mass) obtained by copolymerizing 79% by mass of n-butyl acrylate, 20% by mass of methyl acrylate, and 1% by mass of 2-hydroxyethyl acrylate 100 parts by mass -Toluene and xylylene diisocyanate-based trifunctional adduct (trade name: TD-75, concentration 75% by mass, manufactured by Soken Chemical Co., Ltd.) 0.1 part by mass [for glass scattering prevention film for image display device and image display device Production]
The roll-shaped optical films 1 to 16 produced in Example 1 were wrapped in an aluminum moisture-proof sheet, stored for 30 days in a thermostatic bath at a temperature of 80 ° C. and a relative humidity of 80% assuming long-term transportation, and a durability test was performed.

  After the durability test, the adhesive layers of the substrate-less pressure-sensitive adhesive sheet were bonded to both surfaces of the optical films 1 to 16 to obtain glass scattering prevention films 1 to 16 for an image display device.

  Next, after bonding the glass plate having a thickness of 1 mm and the side opposite to the surface on which the functional layer is provided, the adhesive layer of the base material-less pressure-sensitive adhesive sheet of each functional layer is attached to a liquid crystal display device with a touch panel ( Image display devices 1 to 16 were prepared by bonding to a model name: LCD-USB10XB-T (manufactured by I / O Data Equipment Co., Ltd.), and the visibility was evaluated according to the following criteria.

<Evaluation>
・ Visibility evaluation In the room where 10 sets are arranged at 1.5m intervals with 2 sets of 40W x 2 daylight straight tube fluorescent lamps (FLR40S, D / MX manufactured by Panasonic Corporation) on the ceiling. The display device was observed from various angles in a black display state, and the state of reflected light reflected on the image display device was evaluated according to the following criteria.

Evaluation criteria ○: The level at which the reflected light reflected on the image display device cannot be seen at all.

×: Level at which reflected light reflected on the image display device is slightly seen and causes a problem in practice XX: Level at which reflected light reflected on the image display device can be clearly confirmed.
・ Evaluation of scattering prevention of glass scattering prevention film for image display device Substrate-free only on the uncoated surface (surface opposite to the surface on which the functional layer is provided) of optical films 1 to 16 after the durability test The glass scattering prevention films 1-16 for image display apparatuses which bonded the adhesive layer of the adhesive sheet were bonded together with the glass plate of thickness 1mm.

Then, the laminated body which consists of a glass plate and a scattering prevention film was arrange | positioned so that a scattering prevention film might face upwards on a stand with a height of 10 mm. Next, an iron ball was dropped from a height of 30 cm onto the anti-scattering film of the laminate, and the glass scattering state was visually observed and evaluated according to the following criteria.
<Evaluation>
-Glass scattering prevention evaluation criteria ○: The scattering prevention film did not tear.

  Δ: The scattering prevention film was slightly torn. This is a practically problematic level.

  X: The scattering prevention film was torn.

  As can be seen from the results in Table 3, the glass scattering prevention film for an image display device composed of the optical film of the present invention has excellent visibility when used in a liquid crystal display device with a touch panel, and also has a glass scattering prevention property. It turns out that it is excellent.

DESCRIPTION OF SYMBOLS 1 Localized phase 2 Functional layer 3 Base film 4 Fine particle 5 Curable resin L Thickness of functional layer 30 Image display apparatus 31 Image display panel 32 Adhesive layer 33 Conductive glass substrate 34 Glass substrate 35 Conductive film 41 Glass scattering prevention film 42 for image display device Hard coat film 43 Adhesive layer

Claims (4)

An optical film in which a functional layer containing a resin material and fine particles dispersed in the resin material is formed as a single layer on at least one surface of a base film containing a matting agent having a primary average particle size of 20 nm or less A manufacturing method of
The base film is formed by a solution casting film forming method in which a dope is cast on a belt-like metal support so that the matting agent is localized on the air surface side during belt casting film formation. The coating composition for forming the functional layer satisfies the following (A) to (C), the coating composition is applied to a base film so that the thickness after drying is 1 μm or more, and then cured, When the thickness of the functional layer is L, 50% by mass or more of the fine particles contained in the functional layer is contained in a region less than 1/2 L in the thickness direction from the surface opposite to the base film. method for producing an optical film, characterized in that the localized phase is formed, and the functional layer, the matting agent of the base film is formed on a surface localized.
(A) The resin material is a curable resin.
(B) The fine particles have a refractive index lower than that of the resin material by 0.04 or more.
(C) An organic solvent that swells or dissolves the base film is contained. The method for producing an optical film according to claim 1, wherein a refractive index of the fine particles is in a range of 1.35 to 1.45. The method for producing an optical film according to claim 1 , wherein the base film is a cellulose ester film . The film thickness of the said base film is in the range of 5-40 micrometers, The manufacturing method of the optical film as described in any one of Claims 1-3 characterized by the above-mentioned.