JP4080520B2 - Antiglare hard coat film, method for producing antiglare hard coat film, optical element, polarizing plate and image display device - Google Patents

Description

  The present invention relates to an antiglare hard coat film, a method for producing an antiglare hard coat film, an optical element, a polarizing plate, and an image display device.

  Along with the advancement of technology in recent years, in addition to the conventional CRT (Cathode Ray Tube), liquid crystal displays (LCD), plasma displays (PDP), electroluminescent displays (ELD), etc. have been developed and put into practical use. ing. Among these, LCDs are changing from notebook personal computers and monitors to televisions due to technological innovations such as high viewing angles, high definition, high speed response, and color reproducibility. . The basic structure of an LCD is that a glass substrate on a flat plate, each with a transparent electrode, is placed oppositely through a spacer so as to form a gap with a constant interval, and a liquid crystal material is injected between the glass substrates and sealed. The liquid crystal cell is further provided with polarizing plates on the outer surfaces of the pair of glass substrates. Conventionally, a cover plate made of glass or plastic is attached to the surface of the liquid crystal cell to prevent damage to the polarizing plate attached to the surface of the liquid crystal cell. However, when a cover plate is attached, it is disadvantageous in terms of cost and weight, and a hard coat treatment is gradually applied to the surface of the polarizing plate. In the hard coat treatment, an antiglare hard coat film is generally used to prevent reflection of a light source on the LCD.

  The antiglare hard coat film has a thin hard coat layer of about 2 to 10 μm formed on one or both sides of a transparent plastic film substrate using a resin such as a thermosetting resin or an ultraviolet curable resin and fine particles. Is obtained. The surface of the hard coat layer becomes uneven due to the fine particles, thereby exhibiting antiglare properties. When the resin is coated on glass and a hard coat layer is provided, the pencil hardness shows a hardness of 4H or more, but when the base is a transparent plastic film substrate, the thickness of the hard coat layer is If not sufficient, the pencil hardness is generally lowered to 3H or less due to the influence of the transparent plastic film substrate.

  With the transition of LCD applications to home TVs, general home TV users can handle TVs using LCDs in the same way as TVs using conventional glass CRTs. Easy to assume. Since the pencil hardness of glass CRT is about 9H, the improvement in hardness is required for the antiglare hard coat film used in the LCD.

  The hardness of the antiglare hard coat film can be improved by increasing the thickness of the hard coat layer. However, when the layer thickness is increased, there is a possibility that particles contained in the hard coat layer are completely embedded in the hard coat layer and sufficient antiglare property (antiglare property) cannot be exhibited. In order to solve this problem, there is a method of increasing the addition amount of the fine particles, but in this case, there is also a problem that the number of particles in the layer direction increases and as a result, the haze value increases. Techniques described in the following Patent Documents 1 to 4 have been proposed for increasing the hardness of an antiglare hard coat film and the problems associated with antiglare properties and haze values.

  Patent Document 1 discloses an anti-glare film in which a hard coat layer mainly composed of particles having an average particle diameter of 0.6 to 20 μm, fine particles having an average particle diameter of 1 to 500 nm, and a hard coat resin is formed on a transparent substrate film. A hard coat film is disclosed. Further, it is described that the thickness of the hard coat layer is not more than the particle diameter of the particles, preferably not more than 80% of the average particle diameter (specifically, not more than 16 μm).

  Patent Document 2 discloses a hard coat film in which at least one hard coat layer is formed on at least one surface of a plastic base film, and the thickness of the hard coat layer is 3 to 30 μm. Further, it is described that inorganic fine particles having a secondary particle size of 20 μm or less are added to the hard coat layer. Furthermore, there is a description that the surface of the hard coat layer is uneven to impart antiglare properties.

  Patent Document 3 discloses an antireflection film obtained by laminating a hard coat film layer, a metal alkoxide and a hydrolyzate thereof as a main component on at least one surface of a plastic film, An antireflection film having an elastic modulus of 0.7 to 5.5 GPa below the fracture strain of the layer is disclosed. It also describes that the film thickness of the hard coat layer is 0.5 μm or more and 20 μm or less, and the average particle diameter of the fine particles contained in the hard coat layer is 0.01 to 10 μm.

  Patent Document 4 discloses an antiglare hard coat layer containing particles having an average particle diameter of 1 to 10 μm, inorganic fine particles having an average particle diameter of 0.001 to 0.2 μm, and photocurability on a transparent support. Of the organosilane hydrolyzate and / or its partial condensate, and a low-refractive index layer having a refractive index in the range of 1.35 to 1.49, which is sequentially formed from a composition containing a fluorine-containing polymer An antiglare antireflection film is disclosed which has a haze value in the range of 3 to 20% and an average reflectance of 450 nm to 650 nm of 1.8% or less. . In addition, this document describes that the film thickness of the antiglare hard coat layer is 1 to 10 μm.

  However, it cannot be said that these conventional antiglare hard coat films have sufficiently solved both problems of hardness and antiglare property. First, in the said patent document 1, when the thickness of the said hard-coat layer is the said grade, there exists a problem that sufficient hardness cannot be exhibited. In Patent Document 2, in the configuration as described above, the surface roughness of the hard coat layer surface is not considered at all, and the inorganic fine particles are completely embedded in the hard coat layer. In some cases, there is a problem that sufficient antiglare property cannot be exhibited. Although the antireflection film described in Patent Document 3 has improved hardness and scratch resistance, for example, when fine particles having an average particle size of about 1.8 μm are added to a hard coat layer having a thickness of about 20 μm However, there is a problem that the fine particles are completely embedded in the hard coat layer and cannot exhibit sufficient antiglare properties. The antiglare antireflection film described in Patent Document 4 is intended to improve scratch resistance, antiglare properties, etc., but has a problem that sufficient hardness is not obtained.

Japanese Patent Laid-Open No. 11-286083 JP 2000-326447 A JP 2001-194504 A JP 2001-264508 A

  Therefore, the present invention provides an antiglare hard coat film excellent in hardness, scratch resistance and antiglare property, an optical element using the same, a polarizing plate, an image display device, and a method for producing an antiglare hard coat film. Objective.

In order to achieve the above object, the antiglare hard coat film of the present invention is an antiglare hard coat film having a hard coat layer containing fine particles on at least one surface of a transparent plastic film substrate, The thickness of the hard coat layer is in the range of 15 to 30 μm, the weight average particle size of the fine particles is in the range of 30 to 75% of the thickness of the hard coat layer, and the average slope of the uneven shape on the surface of the hard coat layer The angle θa is in the range of 0.4 to 1.5 degrees, the average inclination angle θa is a value defined by the following mathematical formula (1), and the hard coat layer has the following component (A): B) and a hard coat layer forming resin containing the component (C). In the hard coat layer forming resin, the component (B) Percentage It is in the range of 70 to 180 wt%, the proportion of the component (C) is in the range of 25 to 110 wt% with respect to the component (A), and the blending proportion of the fine particles is for forming the hard coat layer It is the range of 2-70 weight part with respect to 100 weight part of the whole resin component of resin.
Component (A): At least one of urethane acrylate and urethane methacrylate (B) Component: At least one of polyol acrylate and polyol methacrylate (C) Component: Polymer or copolymer formed from at least one of the following (C1) and (C2) Or mixed polymer (C1) of the above polymer and copolymer: alkyl acrylate having an alkyl group having at least one group of hydroxyl group and acryloyl group (C2): alkyl methacrylate having an alkyl group having at least one group of hydroxyl group and acryloyl group

Average inclination angle θa = tan ⁻¹ Δa (1)
Δa: In the reference length L of the roughness curve defined in JIS B 0601 (1994 version), the sum of the difference (height h) between the apex of the adjacent mountain and the lowest point of the valley is the reference length. Value divided by L

The method for producing an antiglare hard coat film of the present invention is a method for producing an antiglare hard coat film having a hard coat layer containing fine particles on at least one surface of a transparent plastic film substrate, the hard coat film comprising: Preparing a hard coat layer forming material comprising a layer forming resin, fine particles having a weight average particle diameter in the range of 30 to 75% of the thickness of the hard coat layer, and a solvent; and The step of coating the at least one surface of the transparent plastic film substrate to form a coating film, the coating film is cured, the thickness thereof is in the range of 15 to 30 μm, and the average of the uneven shape on the surface tilt angle θa is and forming a hard coat layer is in the range of 0.4 to 1.5 degrees, the average tilt angle θa is a value defined by the following equation (1), before A hard coat layer-forming resin, the component (A) below, (B) comprises a component and the component (C), in the hard coat layer-forming resin for the component (A), the component (B) The ratio of the component (C) is in the range of 25 to 110% by weight with respect to the component (A), and the blending ratio of the fine particles is the hard coat. It is the range of 2-70 weight part with respect to 100 weight part of the whole resin component of resin for layer formation .
Component (A): At least one of urethane acrylate and urethane methacrylate (B) Component: At least one of polyol acrylate and polyol methacrylate (C) Component: Polymer or copolymer formed from at least one of the following (C1) and (C2) Or mixed polymer (C1) of the above polymer and copolymer: alkyl acrylate having an alkyl group having at least one group of hydroxyl group and acryloyl group (C2): alkyl methacrylate having an alkyl group having at least one group of hydroxyl group and acryloyl group

Average inclination angle θa = tan ⁻¹ Δa (1)
Δa: In the reference length L of the roughness curve defined in JIS B 0601 (1994 version), the sum of the difference (height h) between the apex of the adjacent mountain and the lowest point of the valley is the reference length. Value divided by L

  The optical element of the present invention is an optical element in which an antiglare hard coat film is disposed on at least one surface of an optical member, and the antiglare hard coat film is the antiglare hard coat film of the present invention. It is characterized by being.

  The polarizing plate of the present invention is a polarizing plate having a polarizer and an antiglare hard coat film, wherein the antiglare hard coat film is the antiglare hard coat film of the present invention. .

  The image display device of the present invention is an image display device comprising an antiglare hard coat film, an optical element or a polarizing plate, wherein the hard coat film is the hard coat film of the present invention, and the optical element is the book. An optical element of the invention, wherein the polarizing plate is the polarizing plate of the invention.

In the hard-coated antiglare film of the present invention, since the thickness of the hard coat layer is a predetermined range, the hardness becomes sufficient, in the range particle size of the predetermined said microparticles, said microparticles Since the blending ratio is in the predetermined range and the average inclination angle θa of the uneven shape on the hard coat layer surface is in the predetermined range, the antiglare property is excellent and the scratch resistance is also excellent. Therefore, the image display device to which the antiglare hard coat film of the present invention is applied has an excellent image display characteristic because the screen is appropriately protected, the handleability is excellent, and the antiglare property is excellent. Further, in the antiglare hard coat film of the present invention, the hard coat layer is formed using a resin for forming a hard coat layer containing the three components in a proportion of the predetermined range , and the fine particles are the predetermined particles. Since it mix | blends in the ratio of a range , hardness improves more, the crack of a hard-coat layer is prevented, and the curl generation resulting from the hardening shrinkage | contraction of a hard-coat layer is prevented effectively. Moreover, such a high-performance anti-glare hard coat film of the present invention can be produced by the production method of the present invention. However, the antiglare hard coat film of the present invention may be produced by another production method.

  The component (B) preferably contains at least one of pentaerythritol triacrylate and pentaerythritol tetraacrylate. This is because the hardness is further improved, the flexibility is maintained, and the occurrence of curling can be prevented more effectively.

  In the antiglare hard coat film of the present invention, an antireflection layer may be formed on the hard coat layer. The antireflection layer preferably contains hollow and spherical silicon oxide ultrafine particles.

  In the antiglare hard coat film of the present invention, the glossiness according to JIS K 7105 is preferably in the range of 50 to 95. The glossiness means a 60 ° specular glossiness of JIS K 7105 (1981 edition).

  In the method for producing an antiglare hard coat film of the present invention, the solvent preferably contains ethyl acetate. This is because, in the obtained antiglare hard coat film, the adhesion between the hard coat layer and the transparent plastic film substrate is improved, and peeling of the hard coat layer can be prevented. It is preferable that the content rate of the said ethyl acetate is 20 weight% or more with respect to the said whole solvent.

  Next, the present invention will be described in detail. However, the present invention is not limited by the following description.

  The antiglare hard coat film of the present invention has a hard coat layer on one side or both sides of a transparent plastic film substrate.

  The transparent plastic film substrate is not particularly limited, but preferably has a visible light transmittance (preferably a light transmittance of 90% or more) and a transparency (preferably a haze value of 1% or less). . Examples of the material for forming the transparent plastic film substrate include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polycarbonate polymers and polymethyl methacrylate. Etc. Examples of the material for forming the transparent plastic film substrate include styrene polymers such as polystyrene and acrylonitrile-styrene copolymers, polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene copolymers. Examples thereof include olefin polymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide. Furthermore, examples of the material for forming the transparent plastic film substrate include imide polymers, sulfone polymers, polyether sulfone polymers, polyether ether ketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, and vinylidene chloride. Examples thereof include polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, epoxy polymers and blends of the aforementioned polymers. Among these, those having a small optical birefringence are preferably used. The antiglare hard coat film of the present invention can also be used for a polarizing plate as a protective film, for example. In this case, as the transparent plastic film substrate, triacetyl cellulose, polycarbonate, acrylic polymer, cyclic A film formed from a polyolefin having a norbornene structure or the like is preferable. In the present invention, the transparent plastic film substrate may be a polarizer itself. With such a configuration, a protective layer made of TAC or the like is not required, and the structure of the polarizing plate can be simplified. Therefore, the number of manufacturing steps of the polarizing plate or the image display device can be reduced, and the production efficiency can be improved. Moreover, if it is such a structure, a polarizing plate can be made thinner. In addition, when the said transparent plastic film base material is a polarizer, a hard-coat layer will play the role as the conventional protective layer. Moreover, if it is such a structure, an anti-glare hard-coat film will serve as the function as a cover plate with which the liquid crystal cell surface is mounted | worn.

  In the present invention, the thickness of the transparent plastic film substrate is not particularly limited, but is preferably in the range of 10 to 500 μm, more preferably in consideration of workability such as strength and handleability and thin layer properties. Is in the range of 20-300 μm, optimally in the range of 30-200 μm. The refractive index of the transparent plastic film substrate is not particularly limited, and is, for example, in the range of 1.30 to 1.80, and preferably in the range of 1.40 to 1.70.

  As described above, the hard coat layer is formed using, for example, a hard coat layer forming resin containing the following components (A), (B), and (C).

Component (A): At least one of urethane acrylate and urethane methacrylate (B) Component: At least one of polyol acrylate and polyol methacrylate (C) Component: Polymer or copolymer formed from at least one of the following (C1) and (C2) Or mixed polymer (C1) of the above polymer and copolymer: alkyl acrylate having an alkyl group having at least one group of hydroxyl group and acryloyl group (C2): alkyl methacrylate having an alkyl group having at least one group of hydroxyl group and acryloyl group

  As said urethane acrylate and urethane methacrylate which are said (A) component, what contains acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, a polyol, and diisocyanate as a structural component is used. For example, by using at least one monomer of acrylic acid, methacrylic acid, acrylic acid ester and methacrylic acid ester and a polyol, at least one of hydroxy acrylate having one or more hydroxyl groups and hydroxy methacrylate having one or more hydroxyl groups is produced. Then, at least one of urethane acrylate and urethane methacrylate can be produced by reacting this with diisocyanate. In the component (A), one type of urethane acrylate or urethane methacrylate may be used alone, or two or more types may be used in combination.

  Examples of acrylic esters include alkyl acrylates such as methyl acrylate, ethyl acrylate, isopropyl acrylate, and butyl acrylate; cycloalkyl acrylates such as cyclohexyl acrylate, and the like. Examples of the methacrylic acid ester include alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, and butyl methacrylate; cycloalkyl methacrylates such as cyclohexyl methacrylate.

  The polyol is a compound having at least two hydroxyl groups, such as ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 2,2,4-trimethyl-1,3-pentanediol, 3-methyl-1,5 -Pentanediol, hydroxypivalic acid neopentyl glycol ester, tricyclodecane dimethylol, 1,4-cyclohexanediol, spiroglycol, tricyclodecane dimethylol, hydrogenated bisphenol A, ethylene oxide-added bisphenol A, propylene glycol Side addition bisphenol A, trimethylolethane, trimethylolpropane, glycerin, 3-methylpentane-1,3,5-triol, pentaerythritol, dipentaerythritol, tripentaerythritol, glucose and the like can be mentioned.

  As said diisocyanate, various aromatic, aliphatic, or alicyclic diisocyanates can be used, for example, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 4 , 4-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 3,3-dimethyl-4,4-diphenyl diisocyanate, xylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-diphenylmethane diisocyanate, and hydrogenated products thereof Is given.

The mixing ratio of the component (A) is not particularly limited. By using the component (A), the flexibility of the hard coat layer to be formed and the adhesion to the transparent plastic film substrate can be improved. From these points and the viewpoint of the hardness of the hard coat layer, the blending ratio of the component (A) is, for example, in the range of 15 to 55% by weight with respect to the entire resin component in the hard coat layer forming material. Preferably, it is in the range of 25 to 45% by weight. The whole resin component means the total amount of the component (A), the component (B) and the component (C), or, when other resin components are used, the total amount of the three components and the total amount of the resin component The same applies hereinafter.

  Examples of the component (B) include pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, 1,6-hexanediol acrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, penta Examples include erythritol tetramethacrylate, dipentaerythritol hexamethacrylate, and 1,6-hexanediol methacrylate. These may be used alone or in combination of two or more. For example, the polyol acrylate is preferably a monomer component made of a polymer of pentaerythritol triacrylate and pentaerythritol tetraacrylate and a mixed component containing pentaerythritol triacrylate and pentaerythritol tetraacrylate.

The blending ratio of (B) is in the range of 70 to 180% by weight, preferably in the range of 100 to 150% by weight, based on the component (A). When the blending ratio of the component (B) is 180% by weight or less with respect to the component (A), it is possible to effectively prevent curing shrinkage of the formed hard coat layer, and as a result, curl of the antiglare hard coat film. Can be prevented and a decrease in flexibility can be prevented. Further, if the blending ratio of the component (B) is 70% by weight or more of the component (A), the hardness of the hard coat layer to be formed can be further improved, and the scratch resistance can be improved. It becomes.

前記式（１）において、Ｒ^１は、−Ｈ若しくは−ＣＨ_３であり、Ｒ^２は、−ＣＨ_２ＣＨ_２ＯＸ若しくは下記一般式（２）で表される基であり、前記Ｘは、−Ｈ若しくは下記一般式（３）で表されるアクリロイル基である。

前記一般式（２）において、前記Ｘは、−Ｈ若しくは下記一般式（３）で表されるアクリロイル基であり、前記Ｘは、同一であってもよいし、異なっていてもよい。

In the component (C), the alkyl group of (C1) and (C2) is not particularly limited, and is, for example, an alkyl group having 1 to 10 carbon atoms, which may be linear or branched. There may be. Examples of the component (C) include a polymer, a copolymer or a mixture of the polymer and the copolymer containing a repeating unit of the following general formula (1).

In the formula (1), R ¹ is —H or —CH ₃ , R ² is —CH ₂ CH ₂ OX or a group represented by the following general formula (2), and the X is — H or an acryloyl group represented by the following general formula (3).

In the general formula (2), X is —H or an acryloyl group represented by the following general formula (3), and the Xs may be the same or different.

  Examples of the component (C) include 2,3-dihydroxypropyl acrylate, 2,3-diacryloyloxypropyl acrylate, 2-hydroxy-3-acryloyloxypropyl acrylate, 2-acryloyloxy-3-hydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate, 2,3-diacryloyloxypropyl methacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, 2-acryloyloxy-3-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-acryloyloxy At least one monomer selected from the group consisting of ethyl acrylate, 2-hydroxyethyl methacrylate and 2-acryloyloxy methacrylate; Formed polymer, a mixture of copolymer or the polymer and the copolymer can be mentioned.

The blending ratio of the component (C) is in the range of 25 to 110% by weight, preferably in the range of 45 to 85% by weight with respect to the component (A). When the blending ratio of the component (C) is 110% by weight or less, the coating property of the hard coat layer forming material becomes excellent, and when the blending ratio of the component (C) is 25% by weight or more, it is formed. Curing shrinkage of the hard coat layer can be prevented, and as a result, curling can be prevented in the antiglare hard coat film.

  The hard coat layer contains fine particles in order to impart an antiglare property by making the surface structure uneven. Examples of the fine particles include inorganic fine particles and organic fine particles. The inorganic fine particles are not particularly limited, and examples thereof include silicon oxide fine particles, titanium oxide fine particles, aluminum oxide fine particles, zinc oxide fine particles, tin oxide fine particles, calcium carbonate fine particles, barium sulfate fine particles, talc fine particles, kaolin fine particles, calcium sulfate fine particles and the like. Can be given. The organic fine particles are not particularly limited, and examples thereof include polymethyl methacrylate acrylate resin powder (PMMA fine particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin powder, melamine resin powder, Examples thereof include polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, and polyfluorinated ethylene resin powder. These inorganic fine particles and organic fine particles may be used alone or in combination of two or more.

  The weight average particle diameter of the fine particles is in the range of 30 to 75%, preferably in the range of 30 to 50% of the film thickness of the hard coat layer. When the weight average particle size of the fine particles is 30% or more, a sufficient uneven shape can be formed on the surface of the hard coat layer, and a sufficient antiglare function can be imparted. On the other hand, if the weight average particle size of the fine particles is 75% or less, the unevenness of the surface can be made appropriate, the appearance can be improved, and the scattering of reflected light is made appropriate. be able to. The weight average particle diameter of the fine particles can be measured, for example, by the method described in Examples described later.

  The shape of the fine particles is not particularly limited, and may be, for example, a bead-like substantially spherical shape or an irregular shape such as a powder. In the present invention, the fine particles are preferably a plurality of types of fine particles having an average particle size of 2 or more. In this case, the fine particles mean that there are two or more groups (fine particle powder) in which a plurality of fine particles having one weight average particle diameter are gathered. As described above, the fine particles are preferably substantially spherical, more preferably substantially spherical fine particles having an aspect ratio of 1.5 or less. This is because if the aspect ratio is 1.5 or less, the average inclination angle θa can be more preferably controlled in the uneven shape on the surface of the hard coat layer.

The mixing ratio of the fine particles is in the range of 2 to 70 parts by weight, preferably in the range of 4 to 50 parts by weight, more preferably in the range of 15 to 40 parts by weight with respect to 100 parts by weight of the whole resin component. is there.

  The average inclination angle θa in the concavo-convex shape on the surface of the hard coat layer is in the range of 0.4 to 1.5 degrees. If the average inclination angle θa is 0.4 degrees or more, the antiglare property is excellent, and if the average inclination angle θa is 1.5 degrees or less, the haze value can be in an appropriate range. In the present invention, the average inclination angle θa is preferably in the range of 0.5 to 1.2 degrees, and more preferably in the range of 0.6 to 1.1 degrees. In the present invention, the average inclination angle θa can be adjusted, for example, by appropriately selecting the type of the resin for forming the hard coat layer, the thickness of the hard coat layer, the type of the fine particles, the average particle diameter of the fine particles, and the like. Those skilled in the art can set the average inclination angle θa within the predetermined range of the present invention without undue trial and error.

In the present invention, the average inclination angle θa is a value defined by the following mathematical formula (1). The average inclination angle θa is, for example, a value measured by a method described in an example described later.
Average inclination angle θa = tan ⁻¹ Δa (1)

In the mathematical formula (1), Δa is a peak length and a valley between adjacent peaks in the reference length L of the roughness curve defined in JIS B 0601 (1994 version) as shown in the following mathematical formula (2). This is a value obtained by dividing the sum (h1 + h2 + h3... + Hn) of the difference (height h) from the lowest point by the reference length L. The roughness curve is a curve obtained by removing a surface waviness component longer than a predetermined wavelength from a cross-sectional curve with a phase difference compensation type high-pass filter. The cross-sectional curve is a contour that appears at the cut end when the target surface is cut along a plane perpendicular to the target surface. FIG. 3 shows an example of the roughness curve, the height h, and the reference line L.
Δa = (h1 + h2 + h3... + Hn) / L (2)

  In the concavo-convex shape of the hard coat layer, the arithmetic average roughness Ra (arithmetic average surface roughness Ra), which is one of the surface roughnesses, is, for example, in the range of 0.05 to 0.3 μm, preferably 0.00. It is the range of 07-0.2 micrometer, More preferably, it is the range of 0.09-0.15 micrometer. The arithmetic average surface roughness Ra is as defined in JIS B 0601 (1994 edition), and is measured, for example, by the method of an example described later. In the present invention, the arithmetic average surface roughness Ra is appropriately selected from, for example, the type of the resin for forming the hard coat layer, the thickness of the hard coat layer, the type of the fine particles, and the weight average particle size of the fine particles. Those skilled in the art can adjust the arithmetic average surface roughness Ra within the predetermined range without undue trial and error.

  From the viewpoint of preventing light scattering and interference fringes generated at the interface between the fine particles and the hard coat layer, it is preferable to reduce the refractive index difference between the fine particles and the hard coat layer. The interference fringes are a phenomenon in which reflected light of external light incident on the hard coat film exhibits a rainbow hue. Recently, three-wavelength fluorescent lamps with excellent clarity are frequently used in offices and the like, and interference fringes appear remarkably under the three-wavelength fluorescent lamps. Since the refractive index of the hard coat layer is generally in the range of 1.4 to 1.6, fine particles having a refractive index close to this refractive index range are preferred. The difference in refractive index between the fine particles and the hard coat layer is preferably less than 0.05.

  When the difference between the refractive index of the transparent plastic film substrate and the refractive index of the hard coat layer is d, the d is preferably 0.04 or less. If d is 0.04 or less, interference fringes can be suppressed. The d is more preferably 0.02 or less.

  The thickness of the hard coat layer is in the range of 15 to 30 μm, and preferably in the range of 18 to 25 μm. When the thickness is within the predetermined range, the hardness of the hard coat layer is sufficient (for example, pencil hardness of 4H or more), and curling can be more effectively prevented.

  The antiglare hard coat film of the present invention comprises, for example, a hard coat layer forming resin containing the three components, a hard coat layer forming material containing the fine particles and a solvent, and the hard coat layer forming material is used as the transparent plastic. It can be manufactured by coating at least one surface of a film substrate to form a coating film, curing the coating film, and forming the hard coat layer.

  The solvent is not particularly limited, and various solvents can be used. For example, dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1, 3,5-trioxane, tetrahydrofuran, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, propionic acid Methyl, ethyl propionate, n-pentyl acetate, acetylacetone, diacetone alcohol, methyl acetoacetate, ethyl acetoacetate, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, -Butanol, 1-pentanol, 2-methyl-2-butanol, cyclohexanol, isobutyl acetate, methyl isobutyl ketone (MIBK), 2-octanone, 2-pentanone, 2-hexanone, 2-heptanone, 3-heptanone, ethylene Examples include glycol monoethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether. These may be used alone or in combination of two or more. In addition, the solvent preferably contains ethyl acetate in a proportion of 20% by weight or more of the whole from the viewpoint of improving the adhesion between the transparent plastic film substrate and the hard coat layer, and more preferably It is to contain ethyl acetate in a proportion of 25% by weight or more, and optimally to contain ethyl acetate in a proportion of 30 to 70% by weight of the whole. If it is 70% by weight or less, the volatilization rate of the solvent can be made appropriate, and coating unevenness and drying unevenness can be effectively prevented. The kind of solvent used in combination with ethyl acetate is not particularly limited, and examples thereof include butyl acetate, methyl ethyl ketone, ethylene glycol monobutyl ether, and propylene glycol monomethyl ether.

  Various leveling agents can be added to the hard coat layer forming material. Examples of the leveling agent include a fluorine-based or silicone-based leveling agent, and a silicone-based leveling agent is preferable. Examples of the silicone leveling agent include reactive silicone, polydimethylsiloxane, polyether-modified polydimethylsiloxane, and polymethylalkylsiloxane. Of these silicone leveling agents, the reactive silicone is particularly preferred. By adding the reactive silicone, slipperiness is imparted to the surface, and scratch resistance is maintained over a long period of time. Further, when the reactive silicone having a hydroxyl group is used, when an antireflection layer (low refractive index layer) containing a siloxane component is formed on the hard coat layer, the antireflection layer and the The adhesion of the hard coat layer is improved.

  The blending amount of the leveling agent is, for example, 5 parts by weight or less, preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the entire resin component.

  In the hard coat layer forming material, pigments, fillers, dispersants, plasticizers, UV absorbers, surfactants, antioxidants, thixotropic agents, etc. are added as necessary, as long as the performance is not impaired. May be. These additives may be used alone or in combination of two or more.

  A conventionally well-known photoinitiator can be used for the said hard-coat layer forming material. Examples of the photopolymerization initiator include 2,2-dimethoxy-2-phenylacetophenone, acetophenone, benzophenone, xanthone, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, benzoisopropyl ether, benzyl Dimethyl ketal, N, N, N ′, N′-tetramethyl-4,4′-diaminobenzophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, etc. In addition, thioxanthone compounds can be used.

  Examples of the method for coating the hard coat layer forming material on a transparent plastic film substrate include, for example, a phanten coating method, a die coating method, a spin coating method, a spray coating method, a gravure coating method, a roll coating method, and a bar coating method. Etc. can be used.

  The hard coat layer forming material is applied to form a coating film on the transparent plastic film substrate, and the coating film is cured. Prior to the curing, the coating film is preferably dried. The drying may be, for example, natural drying, air drying by blowing air, heat drying, or a combination of these.

The means for curing the coating film of the hard coat layer forming material is not particularly limited, but ionizing radiation curing is preferable. Various active energies can be used as the means, but ultraviolet rays are preferred. As the energy ray source, for example, a high pressure mercury lamp, a halogen lamp, a xenon lamp, a metal halide lamp, a nitrogen laser, an electron beam accelerator, a radioactive element, or the like is preferable. The irradiation amount of the energy ray source is preferably 50 to 5000 mJ / cm ² as an integrated exposure amount at an ultraviolet wavelength of 365 nm. When the irradiation amount is 50 mJ / cm ² or more, the curing becomes more sufficient and the hardness of the formed hard coat layer becomes more sufficient. Moreover, if it is 5000 mJ / cm < ² > or less, coloring of the hard-coat layer formed can be prevented and transparency can be improved.

  As described above, the antiglare hard coat film of the present invention can be produced by forming the hard coat layer on at least one surface of the transparent plastic film substrate. In addition, you may manufacture the anti-glare hard coat film of this invention with manufacturing methods other than the above-mentioned method. The hardness of the antiglare hard coat film of the present invention is, for example, 4H or more in pencil hardness.

  An example of the antiglare hard coat film of the present invention is shown in the schematic sectional view of FIG. As shown in the figure, the anti-glare hard coat film 4 of this example has a hard coat layer 2 containing fine particles 3 formed on one surface of a transparent plastic film substrate 1. In addition, this invention is not limited to the structure of FIG. 1, The anti-glare hard coat film in which the hard-coat layer 2 was formed on both surfaces of the transparent plastic film base material 1 may be sufficient. In addition, the hard coat layer 2 in this example is a single layer, but the present invention is not limited to this, and the hard coat layer 2 may have a multilayer structure in which two or more layers are laminated.

  In the antiglare hard coat film of the present invention, an antireflection layer (low refractive index layer) may be disposed on the hard coat layer. An example of the antiglare hard coat film of the present invention having an antireflection layer is shown in the schematic sectional view of FIG. As shown in the figure, the antiglare hard coat film 6 of this example has a hard coat layer 2 containing fine particles 3 formed on one side of a transparent plastic film substrate 1, and an antireflection layer is formed on the hard coat layer 2. 5 is formed. When light strikes an object, it repeats the phenomenon of reflection at the interface, absorption inside, and scattering, and passes through the back of the object. For example, when an anti-glare hard coat film is attached to an image display device, one of the factors that lower the image visibility is the reflection of light at the interface between air and the hard coat layer. The antireflection layer reduces the surface reflection. In the antiglare hard coat film 6 shown in FIG. 2, the hard coat layer 2 and the antireflection layer 5 are formed on one side of the transparent plastic film substrate 1, but the present invention is not limited to this. The hard coat layer 2 and the antireflection layer 5 may be formed on both surfaces of the transparent plastic film substrate 1. Further, in the antiglare hard coat film 6 shown in FIG. 2, the hard coat layer 2 and the antireflection layer 5 are each a single layer, but the present invention is not limited thereto, and the hard coat layer 2 and the antireflection layer are not limited thereto. Each of the layers 5 may have a multilayer structure in which two or more layers are stacked.

  In the present invention, the antireflection layer is an optical thin film in which thickness and refractive index are strictly controlled, or a laminate of two or more optical thin films. The antireflection layer exhibits an antireflection function by canceling out the reversed phases of incident light and reflected light using the interference effect of light. The wavelength region of visible light that exhibits the antireflection function is, for example, 380 to 780 nm, and the wavelength region with particularly high visibility is in the range of 450 to 650 nm, and the reflectance at 550 nm, which is the central wavelength, is minimized. Thus, it is preferable to design the antireflection layer.

  In designing the antireflection layer based on the light interference effect, as a means for improving the interference effect, for example, there is a method of increasing the refractive index difference between the antireflection layer and the hard coat layer. In general, in a multilayer antireflection layer having a structure in which two to five optical thin layers (thin films whose thickness and refractive index are strictly controlled) are laminated, a plurality of components having different refractive indexes are formed in a predetermined thickness. Thus, the degree of freedom in optical design of the antireflection layer is increased, the antireflection effect can be further improved, and the spectral reflection characteristics can be made uniform (flat) in the visible light region. Since the optical thin film requires high thickness accuracy, each layer is generally formed by a dry method such as vacuum evaporation, sputtering, or CVD.

  The multilayer antireflection layer has a two-layer structure in which a low refractive index silicon oxide layer (refractive index: about 1.45) is laminated on a high refractive index titanium oxide layer (refractive index: about 1.8). More preferably, a four-layer structure in which a silicon oxide layer is laminated on a titanium oxide layer, a titanium oxide layer is laminated on the silicon oxide layer, and a silicon oxide layer is laminated on the titanium oxide layer. belongs to. By forming these two-layer antireflection layers or four-layer antireflection layers, it is possible to uniformly reduce reflection in the visible light wavelength region (for example, a range of 380 to 780 nm).

  Further, the antireflection effect can be exhibited also by forming a single-layer optical thin film (antireflection layer) on the hard coat layer. In general, for forming the single-layer antireflection layer, for example, a wet method such as phanten coating, die coating, spin coating, spray coating, gravure coating, roll coating, or bar coating is employed.

  The material for forming the single-layer antireflection layer is, for example, a resin material such as an ultraviolet curable acrylic resin, a hybrid material in which inorganic fine particles such as colloidal silica are dispersed in the resin, tetraethoxysilane, titanium tetraethoxide, or the like. Examples include sol-gel materials using metal alkoxides. Moreover, in the said forming material, what contains a fluorine group is preferable for imparting antifouling properties to the surface. In the forming material, for reasons such as scratch resistance, a forming material having a high inorganic component content is preferable, and the sol-gel material is more preferable. The sol-gel material can be used after partial condensation.

  As an antireflection layer (low refractive index layer), a siloxane oligomer having a number average molecular weight of 500 to 10,000 in terms of ethylene glycol, and a fluorine compound having a polystyrene equivalent number average molecular weight of 5000 or more and having a fluoroalkyl structure and a polysiloxane structure And the like (a material described in JP-A No. 2004-167827) are preferable because they can achieve both scratch resistance and low reflection.

  The antireflection layer (low refractive index layer) may contain an inorganic sol in order to improve the film strength. The inorganic sol is not particularly limited, and examples thereof include inorganic sols such as silica, alumina, and magnesium fluoride. Among these, silica sol is preferable. The blending ratio of the inorganic sol is, for example, in the range of 10 to 80 parts by weight with respect to 100 parts by weight of the total solid content of the antireflection layer forming material. The particle size of the inorganic fine particles in the inorganic sol is preferably in the range of 2 to 50 nm, and more preferably in the range of 5 to 30 nm.

  The material for forming the antireflection layer preferably contains hollow spherical silicon oxide ultrafine particles. The silicon oxide ultrafine particles preferably have an average particle diameter of about 5 to 300 nm, and more preferably in the range of 10 to 200 nm. The silicon oxide ultrafine particles are hollow spheres in which cavities are formed inside the outer shell having pores, and the cavities include at least one of a solvent and a gas at the time of preparing the silicon oxide ultrafine particles. It is. Moreover, it is preferable that the precursor substance for forming the said cavity of the said silicon oxide ultrafine particle remains in the said cavity. The thickness of the outer shell is preferably in the range of about 1 to 50 nm and in the range of about 1/50 to 1/5 of the average particle diameter of the silicon oxide ultrafine particles. The outer shell is preferably formed from a plurality of coating layers. Further, in the silicon oxide ultrafine particles, it is preferable that the pores are closed and the cavity is sealed by the outer shell. This is because the porous or voids of the silicon oxide ultrafine particles are maintained in the antireflection layer, and the refractive index of the antireflection layer can be further reduced. As a method for producing such hollow and spherical silicon oxide ultrafine particles, for example, the method for producing silica-based fine particles disclosed in JP-A-2000-233611 is suitably employed.

  The temperature of drying and curing when forming the antireflection layer (low refractive index layer) is not particularly limited, and is, for example, in the range of 60 to 150 ° C, preferably in the range of 70 to 130 ° C. The drying and curing time is, for example, in the range of 1 to 30 minutes, and when considering productivity, the range of 1 to 10 minutes is preferable. Further, after the drying and curing, a high-hardness antiglare hard coat film having an antireflection layer can be obtained by further heat treatment. The temperature of the heat treatment is not particularly limited, and is, for example, in the range of 40 to 130 ° C., preferably in the range of 50 to 100 ° C. The heat treatment time is not particularly limited, and for example, 1 minute to From the viewpoint of improving scratch resistance for 100 hours, it is more preferable to carry out for 10 hours or more. The heat treatment can be performed by a method using a hot plate, an oven, a belt furnace, or the like.

  When an anti-glare hard coat film having an antireflection layer is mounted on an image display device, the antireflection layer is frequently the outermost layer, and thus is easily contaminated by the external environment. Antireflection layers are more prone to contamination than mere transparent plates.For example, surface reflectance changes due to adhesion of contaminants such as fingerprints, hand dirt, sweat, and hairdressing materials, and the deposits appear white. The displayed content may be unclear. In order to prevent the adhesion of contaminants and improve the ease of removing the adhered contaminants, a contamination prevention layer formed of a fluorine group-containing silane compound or fluorine group-containing organic compound is laminated on the antireflection layer. It is preferable to do.

  In the antiglare hard coat film of the present invention, it is preferable to perform a surface treatment on at least one of the transparent plastic film substrate and the hard coat layer. If the surface of the transparent plastic film substrate is surface-treated, the adhesion with the hard coat layer, the polarizer or the polarizing plate is further improved. In addition, if the surface of the hard coat layer is surface-treated, the adhesion with the antireflection layer, the polarizer or the polarizing plate is further improved. Examples of the surface treatment include low-pressure plasma treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, and acid or alkali treatment. As the surface treatment when a triacetyl cellulose film is used as the transparent plastic film substrate, alkali treatment is preferable. This alkali treatment can be carried out, for example, by bringing the triacetyl cellulose film surface into contact with an alkali solution, washing with water and drying. As the alkaline solution, for example, potassium hydroxide solution and sodium hydroxide solution can be used. The specified concentration (molar concentration) of hydroxide ions in the alkaline solution is preferably in the range of 0.1 to 3.0 N (mol / L), more preferably 0.5 to 2.0 N (mol / L). Range.

  In the antiglare hard coat film in which the hard coat layer is formed on one surface of the transparent plastic film substrate, a solvent treatment may be performed on the other surface in order to prevent curling. The solvent treatment can be carried out by contacting a solvent capable of dissolving the transparent plastic film substrate or a solvent capable of swelling. Curling can be prevented by applying a force to curl the other surface by the solvent treatment and thereby canceling the force to curl by forming the hard coat layer. Similarly, in the antiglare hard coat film in which the hard coat layer is formed on one surface of the transparent plastic film substrate, a transparent resin layer is formed on the other surface in order to prevent curling. Also good. Examples of the transparent resin layer include a layer mainly composed of a thermoplastic resin, a radiation curable resin, a thermosetting resin, and other reactive resins. Among these, a layer mainly composed of a thermoplastic resin is particularly preferable.

  In the antiglare hard coat film of the present invention, the transparent plastic film substrate side can usually be bonded to an optical member used for LCD or ELD via an adhesive or an adhesive. In addition, in this bonding, various surface treatments as described above may be performed on the surface of the transparent plastic film substrate.

  Examples of the optical member include a polarizer and a polarizing plate. In general, the polarizing plate has a transparent protective film on one side or both sides of the polarizer. When providing a transparent protective film on both surfaces of a polarizer, the same material may be sufficient as the transparent protective film of front and back, and a different material may be sufficient as it. The polarizing plates are usually disposed on both sides of the liquid crystal cell. Further, the polarizing plates are arranged so that the absorption axes of the two polarizing plates are substantially orthogonal to each other.

  Next, an optical member in which the antiglare hard coat film of the present invention is laminated will be described by taking a polarizing plate as an example. A polarizing plate having the function of the present invention can be obtained by laminating the antiglare hard coat film of the present invention with a polarizer or a polarizing plate using an adhesive or a pressure-sensitive adhesive.

  The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene / vinyl acetate copolymer partially saponified film, and iodine and dichroic dyes. Examples thereof include a polyene-based oriented film such as a film obtained by adsorbing a chromatic substance and uniaxially stretched, a dehydrated polyvinyl alcohol product or a dehydrochlorinated polyvinyl chloride product. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic substance such as iodine is preferable because of its high polarization dichroic ratio. Although the thickness in particular of the said polarizer is not restrict | limited, For example, it is about 5-80 micrometers.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be produced, for example, by immersing the polyvinyl alcohol film in an aqueous solution of iodine and stretching it 3 to 7 times the original length. The aqueous solution of iodine may contain boric acid, zinc sulfate, zinc chloride or the like, if necessary. Alternatively, the polyvinyl alcohol film may be immersed in an aqueous solution containing boric acid, zinc sulfate, zinc chloride or the like. If necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. By washing the polyvinyl alcohol film with water, it is possible to clean the surface of the polyvinyl alcohol film and anti-blocking agents. In addition, the polyvinyl alcohol film is swollen to prevent unevenness such as uneven coloring. There is also an effect. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As the transparent protective film provided on one side or both sides of the polarizer, those having excellent transparency, mechanical strength, thermal stability, moisture shielding property, retardation value stability and the like are preferable. Examples of the material for forming the transparent protective film include the same materials as those for the transparent plastic film substrate.

  Moreover, as a transparent protective film, the polymer film as described in Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007) is mention | raise | lifted. The polymer film described in the publication includes, for example, (A) a thermoplastic resin having at least one imide group of a substituted imide group and an unsubstituted imide group on the side chain, and (B) a substituted phenyl group and an unsubstituted group on the side chain. Examples thereof include a polymer film formed from a resin composition containing a thermoplastic resin having at least one phenyl group and a nitrile group. Examples of the polymer film formed from the resin composition include a polymer film formed from a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer. can give. The polymer film can be produced by extruding the resin composition into a film. The polymer film has a small phase difference and a small photoelastic coefficient, and therefore, when applied to a protective film such as a polarizing plate, it can eliminate problems such as unevenness due to distortion and has a low moisture permeability. Excellent in humidification durability.

  The transparent protective film is preferably a film made of a cellulose resin such as triacetyl cellulose or a film made of a norbornene resin from the viewpoints of polarization characteristics and durability. Commercially available products of the transparent protective film include, for example, trade name “Fujitac” (Fuji Photo Film Co., Ltd.), trade name “ZEONOR” (manufactured by Nippon Zeon Co., Ltd.), trade name “ARTON” (manufactured by JSR Corporation), and the like. It is done.

  The thickness of the transparent protective film is not particularly limited, but is, for example, in the range of 1 to 500 μm from the viewpoints of workability such as strength, handleability, and thin layer properties. If it is the said range, a polarizer will be protected mechanically, and even if it exposes to high temperature and high humidity, a polarizer will not shrink | contract and it can maintain the stable optical characteristic. The thickness of the transparent protective film is preferably in the range of 5 to 200 μm, and more preferably in the range of 10 to 150 μm.

  The configuration of the polarizing plate laminated with the antiglare hard coat film is not particularly limited. For example, the transparent protective film, the polarizer and the transparent protective film are laminated in this order on the antiglare hard coat film. Alternatively, the polarizer and the transparent protective film may be laminated in this order on the antiglare hard coat film.

  Various optical members such as an antiglare hard coat film of the present invention and a polarizing plate using the same can be preferably used in various image display devices such as liquid crystal display devices. The liquid crystal display device of the present invention has the same configuration as the conventional liquid crystal display device except that the antiglare hard coat film of the present invention is used. For example, it can be manufactured by appropriately assembling components such as a liquid crystal cell, an optical member such as a polarizing plate, and an illumination system (backlight or the like) as necessary, and incorporating a drive circuit. The liquid crystal cell is not particularly limited, and various types such as a TN type, an STN type, and a π type can be used.

  In the present invention, the configuration of the liquid crystal display device is not particularly limited, and a liquid crystal display device in which the optical member is disposed on one side or both sides of a liquid crystal cell, a liquid crystal display device using a backlight or a reflector in an illumination system, and the like. can give. In these liquid crystal display devices, the optical member of the present invention can be disposed on one side or both sides of the liquid crystal cell. When optical members are arranged on both sides of the liquid crystal cell, they may be the same or different. Furthermore, various optical members and optical components such as a diffusion plate, an antiglare layer, an antireflection layer, a protective plate, a prism array, a lens array sheet, a light diffusion plate, and a backlight may be disposed in the liquid crystal display device. Good.

  Next, examples of the present invention will be described together with comparative examples. However, the present invention is not limited by the following examples and comparative examples. Various characteristics in the following examples and comparative examples were evaluated or measured by the following methods.

(Thickness of hard coat layer)
Using a micro gauge thickness meter manufactured by Mitutoyo Corporation, measuring the total thickness of the antiglare hard coat film, and subtracting the thickness of the transparent plastic film substrate from the total thickness, the thickness of the hard coat layer was calculated. . In Table 1, the thickness of the hard coat layer is indicated as “film thickness”.

(Thickness of antireflection layer)
The thickness of the antireflection layer was calculated from the waveform of the interference spectrum using MCPD2000 (trade name) which is an instantaneous multi-side optical system manufactured by Otsuka Electronics Co., Ltd.

(Haze)
According to the haze (cloudiness) of JIS K7136 (1981 version), the haze value was measured using a trade name haze meter HR300 (manufactured by Murakami Color Research Laboratory Co., Ltd.).

(Glossiness)
The glossiness was measured using a trade name digital variable angle gloss system UGV-5DP (manufactured by Suga Test Instruments Co., Ltd.) according to JIS K7105 (1981 version) with a measurement angle of 60 °.

(Pencil hardness)
After placing the antiglare hard coat film on a glass plate with the surface on which the hard coat layer is not formed facing down, the surface of the hard coat layer is subjected to a pencil hardness test described in JIS K-5400 (however, load 500 g) and the pencil hardness was measured.

(Abrasion resistance)
The scratch resistance of the antiglare hard coat film was evaluated by the following test contents.
(1) The sample is cut into a size of at least 25 mm in width and 100 mm in length, and placed on a glass plate.
(2) Steel wool # 0000 is uniformly attached to a smooth cross section of a cylinder with a diameter of 25 mm, and the sample surface is reciprocated 30 times at a speed of about 100 mm per second with a load of 1.5 kg. Judged.
○: No scratch at all.
Δ: There are fine scratches, but the visibility is not affected.
X: There is an obvious scratch and the visibility is impaired.

(Arithmetic average surface roughness Ra and average inclination angle θa)
A glass plate (thickness: 1.3 mm) manufactured by MATSANAMI is bonded to the surface of the antiglare hard coat film on which the hard coat layer is not formed, and a high precision fine shape measuring instrument (trade name; Surfcorder ET4000). The surface shape of the hard coat layer was measured using Kosaka Laboratory Co., Ltd., and the arithmetic average surface roughness Ra value and the average inclination angle θa value were determined. The high-precision fine shape measuring instrument automatically calculates the arithmetic average surface roughness Ra and the average inclination angle θa.

(Reflectance)
By sticking a black acrylic plate (thickness 2.0 mm, manufactured by Mitsubishi Rayon Co., Ltd.) on the surface of the antiglare hard coat film where the hard coat layer is not formed, and forming an adhesive layer having a thickness of about 20 μm, The reflection on the back surface of the antiglare hard coat film was eliminated. With respect to this antiglare hard coat film, the reflectance of the hard coat layer surface was determined. The reflectance is measured by using a spectrophotometer (trade name UV2400PC (with 8 ° tilt integrating sphere)) manufactured by Shimadzu Corporation to measure the spectral reflectance (specular reflectance + diffuse reflectance), C light source / 2 ° field of view. The total reflectance (Y value) was determined by calculation.

(Refractive index of hard coat layer)
The refractive index of the hard coat layer was measured using a multiwavelength Abbe refractometer (manufactured by Atago Co., Ltd., trade name: DR-M2 / 1550).

(Refractive index of fine particles)
Fine particles are placed on a slide glass, a refractive index standard solution is dropped on the fine particles, and a cover glass is placed over to prepare a sample. The sample was observed with a microscope, and the refractive index of the refractive index standard solution in which the contour of the fine particles was most hardly visible at the interface with the refractive index standard solution was defined as the refractive index of the fine particles.

(Adhesion)
The adhesion of the hard coat layer to the transparent plastic film substrate was evaluated by performing a cross-cut peel test described in JIS K 5400. That is, the peeling test was performed 100 times, the number of peeling of the hard coat layer from the film substrate was counted, and the number of peeling / 100 was expressed.

(Weight average particle diameter of fine particles)
Corresponds to the volume of fine particles when the fine particles pass through the fine pores by using a particle size distribution analyzer (trade name: Coulter Multisizer, manufactured by Beckman Coulter, Inc.) using the pore electrical resistance method by the Cole Count method. The number and volume of the fine particles were measured by measuring the electric resistance of the electrolyte solution, and the weight average particle size of the fine particles was measured.

Example 1
Resin raw material containing a resin component containing the following components (A), (B) and (C), and a photopolymerization initiator in a mixed solvent of ethyl acetate and butyl acetate at a solid content concentration of 66% by weight: (Dainippon Ink Co., Ltd., trade name GRANDIC PC1071) was prepared. To 100 parts by weight of the resin raw material, 30 parts by weight of PMMA particles (weight average particle size 10 μm, refractive index 1.49) and 0.5 parts by weight of a leveling agent are added, and further butyl acetate: ethyl acetate (weight ratio) = 55. The hard coat layer forming material was prepared by diluting with ethyl acetate so that the solid concentration was 55 wt%. The leveling agent is a copolymer obtained by copolymerization at a molar ratio of dimethylsiloxane: hydroxypropylsiloxane: 6-isocyanatohexyl isocyanuric acid: aliphatic polyester = 6.3: 1.0: 2.2: 1.0. It is a thing.

Component (A): Urethane acrylate (100 parts by weight) comprising pentaerythritol acrylate and hydrogenated xylene diisocyanate
Component (B): 49 parts by weight of dipentaerythritol hexaacrylate (hereinafter referred to as B1 component (monomer)), 41 parts by weight of pentaerythritol tetraacrylate (hereinafter referred to as component B4 (monomer)) and pentaerythritol triacrylate (hereinafter referred to as component B5) Monomer)) 24 parts by weight (C) component: polymer having a repeating unit represented by the general formula (1), a copolymer or a mixture of the polymer and copolymer (59 parts by weight)
Photopolymerization initiator: Trade name Irgacure 184 (manufactured by Ciba Specialty Chemicals) 3 parts by weight Mixed solvent: butyl acetate: ethyl acetate (weight ratio) = 89: 11

The hard coat layer forming material is coated on a transparent plastic film substrate (80 μm thick triacetyl cellulose film, refractive index: 1.48) using a bar coater and heated at 100 ° C. for 1 minute. The coating was dried by Thereafter, ultraviolet rays having an integrated light quantity of 300 mJ / cm ² were irradiated with a metal halide lamp and cured to form a hard coat layer having a thickness of 20 μm, thereby producing an antiglare hard coat film according to this example.

(Example 2)
In this example, an antiglare hard coat film was produced in the same manner as in Example 1 except that the amount of PMMA particles added was changed to 15 parts by weight.

(Example 3)
In this example, the same method as in Example 1 except that 30 parts by weight of PMMA particles (refractive index 1.49) having a weight average particle diameter of 15 μm were added and the solid content concentration was changed to 35%. Thus, an antiglare hard coat film was produced.

Example 4
In this example, 30 parts by weight of PMMA particles (refractive index 1.49) having a weight average particle size of 8 μm were added, and the film thickness of the hard coat layer was changed to 16 μm. By the method, an antiglare hard coat film was produced.

(Example 5)
In this example, an antiglare hard coat film was produced in the same manner as in Example 1 except that the thickness of the hard coat layer was changed to 16 μm.

(Example 6)
In this example, an antiglare hard coat film was produced in the same manner as in Example 1 except that the film thickness of the hard coat layer was changed to 29 μm.

(Example 7)
In this example, 30 parts by weight of PMMA particles (refractive index 1.49) having a weight average particle diameter of 15 μm were added, and the film thickness of the hard coat layer was changed to 23 μm. By the method, an antiglare hard coat film was produced.

(Example 8)
In this example, an antiglare hard coat film was produced in the same manner as in Example 1 except that an antireflection layer was provided on the hard coat layer.

  The antireflection layer was formed as follows. First, as a material for forming the antireflection layer, a siloxane oligomer (Colcoat N103 (manufactured by Colcoat Co., Ltd., solid content: 2% by weight)) having an average molecular weight in terms of ethylene glycol of 500 to 10,000 is prepared, and the number average molecular weight is determined. It was measured. As a result, the number average molecular weight was 950. In addition, as a fluorine compound having a number average molecular weight in terms of polystyrene of 5000 or more and having a fluoroalkyl structure and a polysiloxane structure, a trade name Opstar JTA105 (manufactured by JSR Corporation, solid content 5% by weight) is prepared. When the number average molecular weight of this fluorine compound was measured, the number average molecular weight in terms of polystyrene was 8,000. Moreover, as a hardening | curing agent, brand name JTA105A (The product made from JSR Corporation, solid content 5 weight%) was used.

  Next, 100 parts by weight of OPSTAR JTA105, 1 part by weight of JTA105A, 590 parts by weight of Colcoat N103 and 151.5 parts by weight of butyl acetate were mixed to prepare an antireflection layer forming material. This antireflection layer-forming material is coated on the hard coat layer with a die coater so as to have the same width as the hard coat layer, and dried and cured by heating at 120 ° C. for 3 minutes to form an antireflection layer ( A low refractive index layer having a thickness of 0.1 μm and a refractive index of 1.43) was formed.

Example 9
In this example, an antireflection layer was formed on the hard coat layer of the antiglare hard coat film obtained in Example 1 to produce an antiglare antireflection hard coat film.

  The antireflection layer was formed as follows. That is, 100 parts by weight of dipentaerythritol acrylate, 15 parts by weight of a silicone polymer having a methacryloxypropyl group and a butyl group, 2.5 parts by weight of hexanediol acrylate, 6 parts by weight of a lucillin type photopolymerization initiator, Surface treatment is performed with a silane coupling agent having an acrylic group, and a hydrophobic spherical and spherical silicon oxide ultrafine particle having a diameter of 60 nm is mixed with a mixed solvent (IPA / MIBK / Puchicello / toluene (80/9 / 10.5 / 0.5)) and adjusted so that the solid content was 3% by weight to obtain an antireflection layer-forming material. Using this antireflection layer forming material, an antireflection layer was formed on the hard coat layer by the same method as in Example 7.

(Example 10)
First, in the same manner as in Example 1, an antiglare hard coat film according to this example was produced. Next, on the non-hard coat surface of the triacetyl cellulose film (the surface opposite to the surface on which the hard coat layer is formed), a coating solution described later is applied with a wire bar so that the wet thickness becomes 20 μm. And a drying treatment at 80 ° C. for 1 minute. As the coating solution, a mixed solvent of acetone: ethyl acetate: IPA (isopropyl alcohol) = 37: 58: 5 (weight ratio) was used.

(Example 11)
First, in the same manner as in Example 1, an antiglare hard coat film according to this example was produced. Next, on the non-hard coat surface of the triacetyl cellulose film (the surface opposite to the surface on which the hard coat layer is formed), a coating solution described later is applied with a wire bar so that the wet thickness becomes 20 μm. And a drying treatment at 80 ° C. for 1 minute. As the coating solution, diacetyl cellulose is mixed with a mixed solvent of acetone: ethyl acetate: IPA (isopropyl alcohol) = 37: 58: 5 (weight ratio) so that the solid content concentration is 0.5% by weight. What was blended was used.

(Example 12)
In this example, an antiglare hard coat film was produced in the same manner as in Example 1 except that no leveling agent was used.

(Comparative Example 1)
100 parts by weight of urethane acrylate ultraviolet curable resin, 15 parts by weight of polystyrene particles (refractive index: 1.59) having a weight average particle size of 3.5 μm, leveling agent (trade name: MegaFuck F470N, Dainippon Ink & Chemicals, Inc.) Co., Ltd.) 0.5 parts by weight, synthetic smectite 2.5 parts by weight, photopolymerization initiator (trade name; Irgacure 907, Ciba Specialty Chemicals) 5 parts by weight, mixed solvent of butyl acetate and toluene (acetic acid The material for forming the hard coat layer was prepared by diluting with a butyl: toluene = 13: 87 weight ratio) so that the solid content concentration was 35% by weight.

Next, the material for forming the hard coat layer is coated on a transparent plastic film substrate (80 μm thick triacetyl cellulose film, refractive index: 1.48) with a bar coater to form a coating film, This coating film was dried by heating at 100 ° C. for 1 minute. Further, the coating film was irradiated with ultraviolet rays having an integrated light quantity of 300 mJ / cm ² with a metal halide lamp and cured to form a hard coat layer having a thickness of 5 μm. This produced the anti-glare hard coat film concerning this comparative example.

(Comparative Example 2)
In this comparative example, an antiglare hard coat film according to this comparative example was obtained in the same manner as in Example 1 except that the amount of PMMA particles added was changed to 3 parts by weight.

(Comparative Example 3)
In this comparative example, an antiglare hard coat film according to this comparative example was obtained in the same manner as in Example 1 except that the amount of PMMA particles added was changed to 70 parts by weight.

(Comparative Example 4)
In this Comparative Example, the same method as Comparative Example 1 except that the fine particles were PMMA particles (refractive index: 1.49) having a weight average particle diameter of 3 μm and the addition amount was changed to 30 parts by weight. Thus, an antiglare hard coat film according to this comparative example was obtained.

  Various properties were measured or evaluated for the antiglare hard coat films of Examples and Comparative Examples thus obtained. The results are shown in Table 1 below.

  As shown in Table 1, the antiglare hard coat film of this example was excellent in all the characteristics of hardness, scratch resistance, antiglare property and adhesion. On the other hand, the antiglare hard coat film of Comparative Example 1 has insufficient hardness, and the antiglare hard coat film of Comparative Example 2 is inferior in antiglare property. The coated film was inferior in scratch resistance.

  The antiglare hard coat film of the present invention is excellent in hardness, scratch resistance and antiglare property. Therefore, the antiglare hard coat film of the present invention can be suitably used for various image display devices such as an optical element such as a polarizing plate, CRT, LCD, PDP, and ELD. It is applicable to.

FIG. 1 is a schematic cross-sectional view showing the structure of an example of the antiglare hard coat film of the present invention. FIG. 2 is a schematic cross-sectional view showing the structure of another example of the antiglare hard coat film of the present invention. FIG. 3 is a schematic diagram illustrating an example of the relationship between the roughness curve, the height h, and the reference length L.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent plastic film base material 2 Hard coat layer 3 Fine particle 4, 6 Anti-glare hard coat film 5 Antireflection layer

Claims (12)

An antiglare hard coat film having a hard coat layer containing fine particles on at least one surface of a transparent plastic film substrate,
The hard coat layer has a thickness in the range of 15 to 30 μm,
The weight average particle size of the fine particles is in the range of 30 to 75% of the thickness of the hard coat layer;
The average inclination angle θa of the concavo-convex shape on the surface of the hard coat layer is in the range of 0.4 to 1.5 degrees,
The average inclination angle θa is a value defined by the following mathematical formula (1),
The hard coat layer is formed using a hard coat layer forming resin containing the following component (A), component (B) and component (C):
In the hard coat layer forming resin,
The ratio of the component (B) to the component (A) is in the range of 70 to 180% by weight,
The ratio of the component (C) to the component (A) is in the range of 25 to 110% by weight,
The antiglare hard coat film , wherein the blending ratio of the fine particles is in the range of 2 to 70 parts by weight with respect to 100 parts by weight of the entire resin component of the resin for forming the hard coat layer .
Component (A): At least one of urethane acrylate and urethane methacrylate (B) Component: At least one of polyol acrylate and polyol methacrylate (C) Component: Polymer or copolymer formed from at least one of the following (C1) and (C2) Or mixed polymer (C1) of the above polymer and copolymer: alkyl acrylate having an alkyl group having at least one group of hydroxyl group and acryloyl group (C2): alkyl methacrylate having an alkyl group having at least one group of hydroxyl group and acryloyl group

Average inclination angle θa = tan ⁻¹ Δa (1)
Δa: In the reference length L of the roughness curve defined in JIS B 0601 (1994 version), the sum of the difference (height h) between the apex of the adjacent mountain and the lowest point of the valley is the reference length. Value divided by L
The antiglare hard coat film according to claim 1, wherein the component (B) contains at least one of pentaerythritol triacrylate and pentaerythritol tetraacrylate. The anti-glare hard coat film according to claim 1, wherein an antireflection layer is formed on the hard coat layer. The anti-glare hard coat film according to claim 3, wherein the antireflection layer contains hollow spherical silicon oxide ultrafine particles. The antiglare hard coat film according to any one of claims 1 to 4, wherein the glossiness according to JIS K 7105 is in the range of 50 to 95. A method for producing an antiglare hard coat film having a hard coat layer containing fine particles on at least one surface of a transparent plastic film substrate,
Preparing a hard coat layer forming material comprising a hard coat layer forming resin, fine particles having a weight average particle diameter in the range of 30 to 75% of the thickness of the hard coat layer, and a solvent;
Applying the hard coat layer forming material to at least one surface of the transparent plastic film substrate to form a coating film;
A step of curing the coating film to form a hard coat layer having a thickness in the range of 15 to 30 μm and an average inclination angle θa of the concavo-convex shape of the surface in the range of 0.4 to 1.5 degrees; Have
The average inclination angle θa is a value defined by the following mathematical formula (1),
The hard coat layer forming resin includes the following components (A), (B) and (C):
In the hard coat layer forming resin,
The ratio of the component (B) to the component (A) is in the range of 70 to 180% by weight,
The ratio of the component (C) to the component (A) is in the range of 25 to 110% by weight,
The method for producing an antiglare hard coat film , wherein the mixing ratio of the fine particles is in the range of 2 to 70 parts by weight with respect to 100 parts by weight of the entire resin component of the resin for forming a hard coat layer .
Component (A): At least one of urethane acrylate and urethane methacrylate (B) Component: At least one of polyol acrylate and polyol methacrylate (C) Component: Polymer or copolymer formed from at least one of the following (C1) and (C2) Or mixed polymer (C1) of the above polymer and copolymer: alkyl acrylate having an alkyl group having at least one group of hydroxyl group and acryloyl group (C2): alkyl methacrylate having an alkyl group having at least one group of hydroxyl group and acryloyl group

Average inclination angle θa = tan ⁻¹ Δa (1)
Δa: In the reference length L of the roughness curve defined in JIS B 0601 (1994 version), the sum of the difference (height h) between the apex of the adjacent mountain and the lowest point of the valley is the reference length. Value divided by L
The method for producing an antiglare hard coat film according to claim 6, wherein the component (B) contains at least one of pentaerythritol triacrylate and pentaerythritol tetraacrylate. The method for producing an antiglare hard coat film according to claim 6 or 7, wherein the solvent contains ethyl acetate. The method for producing an antiglare hard coat film according to claim 8, wherein a content ratio of the ethyl acetate is 20% by weight or more based on the whole solvent. An anti-glare hard coat film according to any one of claims 1 to 5, wherein the anti-glare hard coat film is an optical element having an anti-glare hard coat film disposed on at least one surface of the optical member. An optical element, which is a coat film. A polarizing plate having a polarizer and an antiglare hard coat film, wherein the antiglare hard coat film is the antiglare hard coat film according to any one of claims 1 to 5. A polarizing plate. An image display device comprising an antiglare hard coat film, an optical element or a polarizing plate, wherein the hard coat film is the hard coat film according to any one of claims 1 to 5, and the optical element is claimed. An optical display device according to item 10, wherein the polarizing plate is the polarizing plate according to claim 11.

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