JP2009075360A - Optical film, polarizing plate, image display apparatus and method of manufacturing optical film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film excellent in an anti-glare performance and black sharpness and a method of manufacturing the optical film and to provide a polarizing plate and an image display apparatus using the optical film. <P>SOLUTION: The optical film has an anti-glare layer on a transparent support, the anti-glare layer has a matrix constituting it and at least two kinds of translucent particles. At least one kind of the translucent particle (particle A) has an average particle diameter of 5.5 to 15.0 μm and at least one kind thereof (particle B) has an average particle diameter of 105% to 135% to that of the particle A. Film thickness of the anti-glare layer in the optical film is 8 to 40 μm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical film, a polarizing plate and an image display device having the optical film, and a method for producing the optical film.

  In various image display devices such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescence display (ELD), and cathode ray tube display (CRT), contrast reduction due to reflection of external light and image reflection In order to prevent this, an antiglare film or an antiglare antireflection film is used on the surface of the display. Increased use in office and home environments requires improvements in anti-glare properties that prevent indoor fluorescent lights and viewer images from appearing on the display surface, and further improvements in display contrast in bright places Has been.

  The anti-glare film that obtains anti-glare properties by scattering the light by providing unevenness on the surface has the problem of degrading the image quality that black in the bright place does not tighten due to light scattering on the surface, and anti-glare properties The challenge was to achieve both blackness and blackness. As means for improving this problem, an antiglare film containing fine particles having an average particle diameter of 6 μm to 15 μm has been proposed (for example, see Patent Document 1).

  However, the antiglare film using the particles of the size shown in Patent Document 1 has a problem that it is difficult to obtain the reproducibility of the surface shape at the time of manufacture and it is desired to improve the reproducibility.

JP 2007-41533 A

  An object of the present invention is to provide an antiglare film excellent in antiglare property and black tightening property with good reproducibility. Another object of the present invention is to provide a polarizing plate and an image display device provided with the optical film. Still another object of the present invention is to provide a method for producing an antiglare film having excellent antiglare properties and black tightening properties.

  As a result of intensive studies, the present inventors have found that an antiglare film excellent in antiglare property and blackness can be produced with good reproducibility by using a combination of particles having a specific particle size. The present invention has been completed.

That is, the present inventors achieved the above object with the following configurations.
(1)
An optical film having an antiglare layer on a transparent support, wherein the antiglare layer has a matrix constituting the antiglare layer and at least two kinds of translucent particles, and at least one of the translucent particles is The average particle diameter is 5.5 μm or more and 15.0 μm or less (Particle A), and at least one kind has translucent particles (Particle B) whose average particle diameter is 105% or more and 135% or less with respect to Particle A. An optical film, wherein the film thickness of the antiglare layer is 8 μm or more and 40 μm or less.
(2)
2. The optical film as described in 1 above, wherein the refractive index of A particles is different from that of B particles, and the difference in refractive index is 0.02 or more.
(3)
3. The optical film as described in 1 or 2 above, wherein at least one of the A particles or B particles has a refractive index of 1.54 or more and 1.70 or less, and at least one of the refractive indexes is 1.53 or less.
(4)
4. The optical film as described in any one of 1 to 3 above, wherein a haze value resulting from surface scattering is from 0% to 10%.
(5)
5. The optical film as described in any one of 1 to 4 above, wherein the haze value resulting from internal scattering is 10 to 90%.
(6)
6. The optical film as described in any one of 1 to 5 above, further comprising a layer having a refractive index lower than that of the light scattering layer.
(7)
7. The optical film as described in any one of 1 to 6 above, wherein the integrated reflectance is 3.0% or less.
(8)
In the polarizing plate comprising a polarizing film and two protective films for protecting both the front side and the back side of the polarizing film, at least one of the protective films is the optical film according to any one of 1 to 7 above. A polarizing plate characterized by.
(9)
8. An image display device comprising the optical film according to any one of 1 to 7 or the polarizing plate according to 8.
(10)
A liquid crystal display device comprising the optical film described in any one of 1 to 7 or the polarizing plate described in 8 above.
(11)
A method for producing an optical film having an antiglare layer on a transparent support, wherein the coating solution for the antiglare layer has a matrix constituting the antiglare layer, at least two kinds of translucent particles, and at least two kinds of solvents. At least one of the translucent particles has an average particle size of 5.5 μm to 15.0 μm (particle A), and at least one of the light transmitting particles has an average particle size of 105% to 135% with respect to the particle A. A method for producing an optical film, comprising translucent particles (particle B), wherein the film thickness of the antiglare layer after coating and curing the coating solution for the antiglare layer is 8 μm or more and 40 μm or less.

  According to the present invention, an optical film (antiglare film) excellent in antiglare property and black tightening property can be provided with good reproducibility. Further, according to the present invention, it is possible to provide a polarizing plate and an image display device excellent in antiglare property and black tightening property. According to the present invention, it is possible to provide a manufacturing method in which an optical film excellent in antiglare property and black tightening property has good reproducibility.

  Hereinafter, the present invention will be described in more detail. In the present specification, when a numerical value represents a physical property value, a characteristic value, etc., the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”. . In the present specification, the description “(meth) acrylate” means “at least one of acrylate and methacrylate”. The same applies to “(meth) acrylic acid” and the like.

<Layer structure of optical film>
The optical film of the present invention is an optical film having an antiglare layer on a transparent support, the antiglare layer having a matrix constituting the antiglare layer and at least two kinds of translucent particles, At least one of the conductive particles has an average particle size of 5.5 μm to 15.0 μm (particle A), and at least one of the particles has an average particle size of 105% to 135% with respect to the particle A It is an optical film having (particle B) and having an antiglare layer thickness of 8 μm or more and 40 μm or less.

  The optical film of the present invention has at least one antiglare layer on a transparent support. In the antiglare layer, it is preferable that translucent particles are dispersed in the matrix of the layer. The antiglare layer may be a single layer or a plurality of layers, for example, 2 to 4 layers.

The example of the preferable layer structure of the optical film of this invention is shown below. In the following configuration, the base film refers to a support composed of a film.
・ Base film / antiglare layer ・ Base film / antistatic layer / antiglare layer ・ Base film / antiglare layer / low refractive index layer ・ Base film / antiglare layer / antistatic layer / low refractive index layer -Base film / hard coat layer / antiglare layer / low refractive index layer- Base film / hard coat layer / anti-glare layer / antistatic layer / low refractive index layer-Base film / hard coat layer / antistatic layer / Anti-glare layer / Low refractive index layer -Base film / Anti-glare layer / High refractive index layer / Low refractive index layer -Base film / Anti-glare layer / Medium refractive index layer / High refractive index layer / Low refractive index layer・ Antistatic layer / Base film / Anti-glare layer / Medium refractive index layer / High refractive index layer / Low refractive index layer ・ Base film / Antistatic layer / Anti-glare layer / Medium refractive index layer / High refractive index layer / Low refractive index layer Antistatic layer / base film / antiglare layer / high refractive index layer / low refractive index layer / high refractive index layer / low refractive index layer

  In the optical film of the present invention, layers other than the antiglare layer may be coated, and examples of these layers include a hard coat layer, an antistatic layer, a low refractive index layer, and an antifouling layer. . More preferably, the antiglare layer has functions such as a hard coat layer, an antistatic layer, and an antifouling layer at the same time.

  In the present invention, an antireflection film comprising a medium refractive index layer / a high refractive index layer / a low refractive index layer is preferable from the viewpoint of low reflection. For example, JP-A-8-122504 and 8-110401 are preferable. The configurations described in Japanese Patent Laid-Open No. 10-300902, Japanese Patent Laid-Open No. 2002-243906, Japanese Patent Laid-Open No. 2000-11706, and the like can be given. In terms of simple production and high productivity, the preferred form of the present invention is an optical film having a single antiglare layer on a support, and a single antiglare layer and a single layer on a support. It is an antireflection film having a low refractive index layer in this order.

<Configuration of antiglare layer>
The antiglare layer of the present invention comprises translucent particles (particle A) having an average particle size of 5.5 to 15 μm, particles (particle B) having an average particle size of 105% to 135% with respect to the particle A, and a matrix-forming component ( It is a layer formed by applying, drying, and curing a coating solution containing binder monomers and the like and an organic solvent.

  The coating solution for forming the antiglare layer includes, for example, main monomers for matrix-forming binders that are raw materials for a light-transmitting polymer formed by curing with ionizing radiation, the light-transmitting particles having the specific particle diameter, and a polymerization initiator. Preferably, it contains a polymer compound for adjusting the viscosity of the coating solution, an inorganic fine particle filler for curling reduction and refractive index adjustment, a coating aid and the like.

  The thickness of the antiglare layer is 8 μm to 40 μm, more preferably 10 μm to 35 μm, and most preferably 13 μm to 25 μm. When the thickness is less than 8 μm, the surface irregularities become too large when the light-transmitting particles described below are used, and the black tightening deteriorates, and when it exceeds 40 μm, the surface irregularities become small and the antiglare property is insufficient.

<Translucent particles of antiglare layer>
The average particle diameter of the particles A is 5.5 μm to 15 μm, more preferably 6.0 μm to 12 μm, and even more preferably 6.0 μm to 10 μm. The average particle size of the particles B is 5.8 μm to 20 μm, more preferably 6.3 μm to 16.2 μm, and even more preferably 6.3 μm to 13.5 μm. The ratio of the average particle size of the particles B to the particles A is 105% to 135%, and more preferably 110% to 135%.

  In the present invention, the translucent particles preferably include only two types of particles A and particles B, but further include particles C having the same average particle size as either one of particles A or particles B. it can. In the present invention, the light-transmitting particles are dispersed in a coating solution for forming an antiglare layer and coated, dried and cured to form an antiglare layer. The average particle diameter of the translucent particles refers to the primary particle diameter regardless of whether two or more particles are present adjacent to each other in the coating film or independently. However, agglomerated inorganic particles having a primary particle size of about 0.1 μm are dispersed as secondary particles in the coating solution in a size that satisfies the particle size of the present application, and then applied to the secondary particles. Magnitude.

In this invention, it is excellent in stability of the surface shape after preserve | saving a coating liquid as the average particle diameter of particle | grains A and particle | grains B is said range. In addition, the screen is excellent in blackening and has an appropriate anti-glare property.
In the present invention, in order to achieve excellent anti-glare property and black tightening simultaneously, in addition to the above, the ratio of the average particle size φ and the film thickness (t) of both the translucent particles A and B (φ / t) is important. φA / t is preferably 0.3 to 0.7, more preferably 0.35 to 0.65. Especially preferably, it is 0.4-0.6. If φ / t is too large, the surface becomes very rough and the appearance is deteriorated, and if it is too small, the black tightening is deteriorated.

  In the present invention, it is necessary to adjust the refractive index of the particles and the matrix in order to obtain the necessary internal scattering properties. The refractive index difference between at least one of the particles A or B and the matrix is preferably 0.02 to 0.5, more preferably 0.02 to 0.20, and most preferably 0.03 to 0.3. 15. The refractive index difference between the particles A and the particles B may be 0, but is preferably 0.02 to 0.20, and more preferably 0.02 to 0.10.

  In addition, it is also preferable that one of the particles A and the particles B has a refractive index lower than that of the matrix and one of the particles A or B has a higher refractive index than that of the matrix. For example, among the A particles or the B particles, the high refractive index particles preferably have a refractive index of 1.54 to 1.70, more preferably 1.55 to 1.60, and the low refractive index side particles have a refractive index of 1.44 to 1. .53 is preferred, and more preferably 1.46 to 1.52. Due to the difference in refractive index between the particle A and the particle B, the internal scattering and the control of the surface shape are facilitated. Further, the stability of the surface shape after storing the coating solution is improved.

  The reason why the stability of the surface shape is improved before and after storage of the coating solution is not clear, but is estimated as follows. When particles having different refractive indexes are used, the surface state is different, so that the aggregation and dispersion behavior in the matrix is also different. By coexisting particles that are slightly different in particle size and difficult to agglomerate with particles that tend to agglomerate, the particle agglomeration does not progress during storage of the coating solution, and the surface morphology of the applied antiglare layer Stabilization is realized. For example, when a general-purpose polyfunctional acrylate compound is used as a matrix-forming binder, when resin particles having a refractive index of translucent particles of 1.54 or more are used, the tendency of the particles to agglomerate is strong. The surface shape changes easily. By mixing particles having different particle sizes, it is possible to suppress the growth of the size of the aggregates and to stabilize the surface shape. In addition, by mixing particles having a refractive index of 1.53 or less, which has a small aggregating property of the particles themselves, the growth of the aggregates can be more effectively suppressed, and the stabilization of the surface morphology is achieved.

  The addition amount of the particles A is preferably 1 to 30% by mass in the total solid content of the light scattering layer, more preferably 2 to 25% by mass, and most preferably 2 to 20% by mass. The addition amount of the particles B is preferably 1 to 30% by mass, more preferably 2 to 25% by mass, and most preferably 2 to 20% by mass in the total solid content of the light scattering layer. The mass ratio of particles A to all particles is preferably 10% to 90%, more preferably 20% to 80%, and most preferably 20% to 40% or 60% to 80%. When the ratio of the particles is this ratio, the effect of reducing the variation in the surface morphology of the coating film accompanying the change with time of the coating solution, which is an effect of the present invention, is excellent.

  Particle A and particle B can be selected from the particles described below according to the desired refractive index and average particle size.

  In the present invention, resin particles and / or inorganic fine particles are used as the translucent particles.

  Specific examples of the resin particles include, for example, crosslinked polymethyl methacrylate particles, crosslinked methyl methacrylate-styrene copolymer particles, crosslinked polystyrene particles, crosslinked methyl methacrylate-methyl acrylate copolymer particles, crosslinked acrylate-styrene copolymer particles, Preferred examples include resin particles such as melamine / formaldehyde resin particles and benzoguanamine / formaldehyde resin particles. Of these, crosslinked styrene particles, crosslinked polymethyl methacrylate particles, crosslinked methyl methacrylate-styrene copolymer particles, and the like are preferable. Furthermore, the surface of these resin particles is a so-called surface-modified particle in which a compound containing a fluorine atom, a silicon atom, a carboxyl group, a hydroxyl group, an amino group, an sulfonic acid group, a phosphoric acid group, or the like is chemically bonded. The particle | grains which couple | bonded the inorganic fine particle of the size to the surface are also mentioned preferably. Moreover, inorganic fine particles can also be used as the translucent particles. Specific examples of the inorganic fine particles include silica particles and alumina particles, and silica particles are particularly preferably used.

  In the present invention, in the case where the unevenness of coating and the unevenness of interference are inconspicuous, or from the viewpoint of cost, the refractive index of the matrix is 1.54 or less, and particularly preferably the refractive index is 1.53 or less. The particles are preferably crosslinked polymethylmethacrylate particles, crosslinked methylmethacrylate-styrene copolymer particles, and silica particles. When using crosslinked methyl methacrylate-styrene copolymer particles, the copolymerization ratio of styrene is preferably 50% or more and 90% or less.

  As the shape of the particle, either a true sphere or an irregular shape can be used. The particle size distribution is preferably monodisperse particles because of the haze value, controllability of diffusibility, and uniformity of the coated surface. For example, when a particle having a particle size of 20% or more than the average particle size is defined as a coarse particle, the proportion of the coarse particle is preferably 1% or less of the total number of particles, more preferably 0.1% or less. Yes, more preferably 0.01% or less. Particles having such a particle size distribution are obtained by classification after a normal synthesis reaction, and particles having a more preferable distribution can be obtained by increasing the number of classifications or increasing the degree of classification.

  The particle size distribution of the particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution. The average particle size is calculated from the obtained particle distribution.

  In the antiglare film of the present invention, the haze value resulting from surface scattering is preferably 0 to 10%, more preferably 0.5 to 5%. By setting the surface haze to this range, an antiglare film excellent in blackening can be obtained. The haze value resulting from internal scattering is preferably 8 to 90%, more preferably 10 to 40%, and most preferably 10 to 30%. By setting the internal haze in this range, it is possible to practically satisfy the two performances of lowering the surface contrast and preventing glare. These hazes can be adjusted by adjusting the type and amount of the light-transmitting particles.

<Binder for matrix formation of antiglare layer>
Although it does not specifically limit as a binder which forms the matrix which forms an anti-glare layer, It is preferable that it is a translucent polymer which has a saturated hydrocarbon chain or a polyether chain as a main chain after hardening by ionizing radiation etc. Moreover, it is preferable that the main binder polymer after hardening has a crosslinked structure.

  As the binder polymer having a saturated hydrocarbon chain as a main chain after curing, an ethylenically unsaturated monomer selected from compounds of the first group described below and a polymer thereof are preferable. Moreover, as a polymer which has a polyether chain as a principal chain, the epoxy-type monomer chosen from the compound of the 2nd group described below and the polymer by these ring-opening are preferable. Furthermore, a polymer of a mixture of these monomers is also preferable.

  In the present invention, as the first group of compounds, the binder polymer having a saturated hydrocarbon chain as the main chain and having a crosslinked structure is a (co) polymer of monomers having two or more ethylenically unsaturated groups. Is preferred. In order to obtain a high refractive index, the monomer structure preferably contains at least one selected from an aromatic ring, a halogen atom other than fluorine, a sulfur atom, a phosphorus atom, and a nitrogen atom.

  As a monomer having two or more ethylenically unsaturated groups used in a binder polymer for forming a light scattering layer, an ester of a polyhydric alcohol and (meth) acrylic acid {for example, ethylene glycol di (meth) Acrylate, 1,4-cyclohexanediacrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) ) Acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-chlorohexanetetrameta Relate, polyurethane polyacrylate, polyester polyacrylate}, vinylbenzene and its derivatives (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinyl sulfone (eg, , Divinylsulfone), (meth) acrylamide (for example, methylenebisacrylamide) and the like.

  Furthermore, resins having two or more ethylenically unsaturated groups, such as relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins And oligomers or prepolymers such as polyfunctional compounds such as polyhydric alcohols. Two or more of these monomers may be used in combination, and the resin having two or more ethylenically unsaturated groups is preferably contained in an amount of 10 to 100% based on the total amount of the binder.

  Polymerization of the monomer having an ethylenically unsaturated group can be performed by irradiation with ionizing radiation or heating in the presence of a photoradical polymerization initiator or a thermal radical polymerization initiator. Accordingly, a coating solution containing a monomer having an ethylenically unsaturated group, a photo radical polymerization initiator or a thermal radical polymerization initiator, and particles, and if necessary, an inorganic filler, a coating aid, other additives, an organic solvent and the like. After coating the coating solution on a transparent support, it is cured by a polymerization reaction with ionizing radiation or heat to form an antiglare layer. It is also preferable to perform ionizing radiation curing and thermal curing together. Commercially available compounds can be used as the photo and thermal polymerization initiators, and they are described in “Latest UV Curing Technology” (p. 159, publisher: Kazuhiro Takahisa, publisher; Technical Information Association, 1991). Issued) and Ciba Specialty Chemicals catalog.

In the present invention, the epoxy compound described below is preferably used as the second group of compounds in order to reduce the curing shrinkage of the cured film. As these monomers having an epoxy group, monomers having two or more epoxy groups in one molecule are preferable, and examples thereof include JP-A Nos. 2004-264563, 2004-264564, and 2005-37737, Examples thereof include epoxy monomers described in JP-A-2005-37738, JP-A-2005-140862, JP-A-2005-140862, JP-A-2005-140863, and JP-A-2002-322430.
The monomer having an epoxy group is preferably contained in an amount of 20 to 100% by mass with respect to all binders constituting the layer in order to reduce curing shrinkage, more preferably 35 to 100% by mass, and more preferably 50 to 100% by mass. It is more preferable to contain.

Examples of photoacid generators that generate cations by the action of light for polymerizing epoxy monomers and compounds include ionic compounds such as triarylsulfonium salts and diaryliodonium salts, and nitrobenzyl esters of sulfonic acids. Non-ionic compounds and the like can be used, and various known photoacid generators such as compounds described in “Organic Materials for Imaging” published by Bunshin Publishing Co., Ltd. (1997) can be used. . Among these, a sulfonium salt or an iodonium salt is particularly preferable, and PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , B (C ₆ F ₅ ) ₄ ^{− and the} like are preferable as a counter ion.

  The polymerization initiator is preferably used in a range of 0.1 to 15 parts by mass with respect to 100 parts by mass of the compound of the first group or the second group in the total amount of the polymerization initiator. Is more preferable.

<High molecular compound of antiglare layer>
The antiglare layer of the present invention may contain a polymer compound. By adding a polymer compound, curing shrinkage can be reduced, and the viscosity of the coating solution can be adjusted.

  The polymer compound has already formed a polymer when added to the coating solution. Examples of the polymer compound include cellulose esters (for example, cellulose triacetate, cellulose diacetate, cellulose propionate, cellulose acetate Pionate, cellulose acetate butyrate, cellulose nitrate, etc.), urethane acrylates, polyester acrylates, (meth) acrylic acid esters (for example, methyl methacrylate / (meth) methyl acrylate copolymer, methyl methacrylate / (Meth) ethyl acrylate copolymer, methyl methacrylate / (meth) butyl acrylate copolymer, methyl methacrylate / styrene copolymer, methyl methacrylate / (meth) acrylic acid copolymer, polymethyl methacrylate Etc.), poly Resins such as styrene are preferably used.

  The polymer compound is preferably from 1 to 50% by mass, more preferably from 5 to 40%, based on the total binder contained in the layer containing the polymer compound, from the viewpoint of the effect on curing shrinkage and the effect of increasing the viscosity of the coating solution. It is preferable to contain in the range of mass%. Further, the molecular weight of the polymer compound is preferably from 30,000 to 400,000 in terms of mass average, more preferably from 50,000 to 300,000, and even more preferably from 50,000 to 200,000.

<Inorganic filler for antiglare layer>
In addition to the above particles A and B, the antiglare layer of the present invention is for the purpose of adjusting the refractive index, adjusting the film strength, reducing the shrinkage of curing, and reducing the reflectance when a low refractive index layer is provided. Accordingly, an inorganic filler can be used. For example, it is made of an oxide containing at least one metal element selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony, and the average particle size of primary particles is generally 0.2 μm or less, preferably It is also preferable to contain a fine high refractive index inorganic filler that is 0.1 μm or less, more preferably 0.06 μm or less and 1 nm or more.

  When it is necessary to lower the refractive index of the matrix in order to adjust the refractive index difference with the particle A or the particle B, a fine low refractive index inorganic filler such as silica fine particles or hollow silica fine particles is used as the inorganic filler. Can be used. The preferred particle size is the same as that of the fine high refractive index inorganic filler.

  The surface of the inorganic filler is preferably subjected to a silane coupling treatment or a titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.

  It is preferable that the addition amount of an inorganic filler is 10-90 mass% of the total mass of a light-scattering layer, More preferably, it is 20-80 mass%, Most preferably, it is 30-75 mass%.

  In addition, since the inorganic filler has a particle size sufficiently shorter than the wavelength of light, scattering does not occur, and the dispersion in which the filler is dispersed in the binder polymer has the property of an optically uniform substance.

<Surfactant of antiglare layer>
In the antiglare layer of the present invention, in order to ensure surface uniformity such as coating unevenness, drying unevenness, point defects, etc., either a fluorine-based surfactant or a silicone-based surfactant, or both, is used for the light scattering layer. It is preferable to contain in the coating composition. In particular, a fluorine-based surfactant is preferably used because an effect of improving surface defects such as coating unevenness, drying unevenness, and point defects of the optical film of the present invention appears with a smaller addition amount.
The purpose is to increase productivity by giving high-speed coating suitability while improving surface uniformity. Preferable examples of the fluorine-based surfactant include compounds described in paragraph numbers 0049 to 0074 of JP2007-188070A.

  The preferable addition amount of the surfactant (particularly the fluorine-based polymer) used in the antiglare layer of the present invention is in the range of 0.001 to 5% by mass, preferably 0.005 to 3% by mass with respect to the coating solution. %, And more preferably in the range of 0.01 to 1% by mass. When the addition amount of the surfactant is 0.001% by mass or more, the effect is sufficient, and by setting the addition amount to 5% by mass or less, the coating film is sufficiently dried and good performance as a coating film (for example, reflection) Rate, scratch resistance).

<Organic solvent of coating solution for antiglare layer>
An organic solvent can be added to the coating composition for forming the antiglare layer.

  As an organic solvent, for example, in an alcohol system, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, isoamyl alcohol, 1-pentanol, n-hexanol, methyl amyl alcohol In the ketone system, methyl isobutyl ketone, methyl ethyl ketone, diethyl ketone, acetone, cyclohexanone, diacetone alcohol, etc., in the ester system, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, isobutyl acetate, n-butyl acetate, Isoamyl acetate, n-amyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, methyl acetate, methyl lactate, ethyl lactate, ether, acetal, 1,4 dioxane, te In hydrocarbons such as lahydrofuran, 2-methylfuran, tetrahydropyran, diethyl acetal, etc., hexane, heptane, octane, isooctane, ligroin, cyclohexane, methylcyclohexane, toluene, xylene, ethylbenzene, styrene, divinylbenzene, etc., halogen hydrocarbons In, carbon tetrachloride, chloroform, methylene chloride, ethylene chloride, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene, tetrachloroethylene, 1,1,1,2-tetrachloroethane In the case of polyhydric alcohols and derivatives thereof, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoacetate, diethylene glycol, In fatty acid systems such as lenglycol, dipropylene glycol, butanediol, hexylene glycol, 1,5-pentanediol, glycerin monoacetate, glycerin ethers, 1,2,6-hexanetriol, formic acid, acetic acid, propionic acid, In the case of nitrogen compounds such as entrained acid, isoentangled acid, isovaleric acid, and lactic acid, formamide, N, N-dimethylformamide, acetamide, acetonitrile, and the like, and in the case of sulfur compounds, dimethyl sulfoxide and the like can be mentioned.

  Among organic solvents, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, acetone, toluene, xylene, ethyl acetate, 1-pentanol and the like are particularly preferable. In addition, an alcohol or a polyhydric alcohol solvent may be appropriately mixed with the organic solvent for the purpose of controlling cohesion. These organic solvents may be used alone or in combination, and the coating composition preferably contains 20 wt% to 90 wt%, and preferably 30 wt% to 80 wt% as the total amount of the organic solvent. More preferably, it is most preferable to contain 40 to 70% by weight. In order to stabilize the surface shape of the antiglare layer, it is preferable to use a solvent having a boiling point of less than 100 ° C. and a solvent having a boiling point of 100 ° C. or more in combination.

<Curing of antiglare layer>
The anti-glare layer can be formed by applying a coating solution to a support, and then carrying out light irradiation, electron beam irradiation, heat treatment or the like to cause crosslinking or polymerization reaction. In the case of ultraviolet irradiation, ultraviolet rays emitted from light such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, etc. can be used. Curing with ultraviolet rays is preferably carried out by nitrogen purge or the like in an atmosphere having an oxygen concentration of 4% by volume or less, more preferably 2% by volume or less, and most preferably 0.5% by volume or less.

  Below, layers other than an anti-glare layer are demonstrated.

<Low refractive index layer>
The optical film of the present invention preferably has a low refractive index layer in order to reduce the reflectance. The refractive index of the low refractive index layer is preferably 1.20 to 1.46, more preferably 1.25 to 1.46, and particularly preferably 1.30 to 1.40. The thickness of the low refractive index layer is preferably 50 to 200 nm, and more preferably 70 to 100 nm. The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, and most preferably 1% or less.

As an aspect of a preferable cured product composition,
(1) A composition containing a fluorine-containing polymer having a crosslinkable or polymerizable functional group,
(2) a composition comprising as a main component a hydrolysis-condensation product of a fluorine-containing organosilane material;
(3) a composition containing a monomer having two or more ethylenically unsaturated groups and inorganic fine particles having a hollow structure;
Is mentioned.

(1) Fluorine-containing compound having a crosslinkable or polymerizable functional group As the fluorine-containing compound having a crosslinkable or polymerizable functional group, co-polymerization of a fluorine-containing monomer and a monomer having a crosslinkable or polymerizable functional group Coalescence can be mentioned. Specific examples of these fluoropolymers are described in JP2003-222702A, JP2003-183322A, and the like.

  As described in JP 2000-17028 A, a curing agent having a polymerizable unsaturated group may be used in combination with the above polymer. Moreover, combined use with the compound which has a fluorine-containing polyfunctional polymerizable unsaturated group as described in Unexamined-Japanese-Patent No. 2002-145952 is also preferable. Examples of the compound having a polyfunctional polymerizable unsaturated group include the above-described monomers having two or more ethylenically unsaturated groups. Moreover, the hydrolysis-condensation product of the organolane described in Unexamined-Japanese-Patent No. 2004-170901 is also preferable, and the hydrolysis-condensation product of the organosilane containing a (meth) acryloyl group is especially preferable. These compounds are particularly preferred because they have a large combined effect for improving scratch resistance, particularly when a compound having a polymerizable unsaturated group is used in the polymer body.

  When the polymer itself does not have sufficient curability, necessary curability can be imparted by blending a crosslinkable compound. For example, when the polymer body contains a hydroxyl group, various amino compounds are preferably used as the curing agent. The amino compound used as the crosslinkable compound is, for example, a compound containing one or both of a hydroxyalkylamino group and an alkoxyalkylamino group in total, specifically, for example, a melamine compound, Examples include urea compounds, benzoguanamine compounds, glycoluril compounds, and the like. For curing these compounds, an organic acid or a salt thereof is preferably used.

(2) Hydrolyzed condensate of fluorine-containing organosilane material A composition containing a hydrolyzed condensate of a fluorine-containing organosilane compound as a main component is also preferable because of its low refractive index and high hardness on the coating film surface. A condensate of a tetraalkoxysilane with a hydrolyzable silanol-containing compound at one or both ends with respect to the fluorinated alkyl group is preferred. The specific composition is described in Unexamined-Japanese-Patent No. 2002-265866, 317152.

(3) A composition containing a monomer having two or more ethylenically unsaturated groups and inorganic fine particles having a hollow structure As yet another preferred embodiment, a low refractive index layer comprising low refractive index particles and a binder can be mentioned. . The low refractive index particles may be organic or inorganic, but particles having pores inside are preferable. Specific examples of the hollow particles are described in the silica-based particles described in JP-A-2002-79616. The particle refractive index is preferably 1.15 to 1.40, more preferably 1.20 to 1.30. Examples of the binder include monomers having two or more ethylenically unsaturated groups described on the page of the antiglare layer.

  It is preferable to add the polymerization initiator described on the page of the antiglare layer to the low refractive index layer of the present invention. When a radically polymerizable compound is contained, 1 to 10 parts by mass, preferably 1 to 5 parts by mass of a polymerization initiator can be used with respect to the compound.

  In the low refractive layer of the present invention, inorganic particles can be used in combination. In order to impart scratch resistance, fine particles having a particle size of 15% to 150%, preferably 30% to 100%, more preferably 45% to 60% of the thickness of the low refractive index layer can be used. .

  In the low refractive index layer of the present invention, for the purpose of imparting properties such as antifouling property, water resistance, chemical resistance, and slipping property, a known polysiloxane-based or fluorine-based antifouling agent, slipping agent, etc. are appropriately used. Can be added.

  In the present invention, the preferred integrated reflectance of the antireflection antiglare film provided with a low refractive index layer or the like is preferably 3.0% or less, more preferably 2.0% or less, and most preferably 1.5%. % Or less and 0.3% or more. By reducing the integrated reflectance, sufficient antiglare properties can be obtained even if the light scattering on the surface of the antiglare film is reduced, so that an antiglare antireflection film excellent in blackening can be obtained.

<Transparent support>
A plastic film is preferably used as the transparent support of the optical film of the present invention. Examples of the polymer forming the plastic film include cellulose acylate (eg, triacetyl cellulose, diacetyl cellulose, typically TAC-TD80U, TD80UF, etc. manufactured by Fuji Film), polyamide, polycarbonate, polyester (eg, polyethylene terephthalate, polyethylene). Naphthalate), polystyrene, polyolefin, norbornene resin (Arton: trade name, manufactured by JSR), amorphous polyolefin (ZEONEX: trade name, manufactured by ZEON CORPORATION), (meth) acrylic resin (ACRYPET VRL20A: product) Name, manufactured by Mitsubishi Rayon Co., Ltd., ring structure-containing acrylic resin described in JP-A No. 2004-70296 and JP-A No. 2006-171464), and the like. Of these, triacetyl cellulose, polyethylene terephthalate, and polyethylene naphthalate are preferable, and triacetyl cellulose is particularly preferable.

  When the optical film of the present invention is used in a liquid crystal display device, it is disposed on the outermost surface of the display by providing an adhesive layer on one side. Moreover, you may combine the optical film and polarizing plate of this invention. When the transparent support is triacetyl cellulose, triacetyl cellulose is used as a protective film for protecting the polarizing layer of the polarizing plate. Therefore, it is preferable in terms of cost to use the optical film of the present invention as it is for the protective film.

When the optical film of the present invention is disposed on the outermost surface of a display by providing an adhesive layer on one side or used as it is as a protective film for a polarizing plate, the optical film on the transparent support is sufficient for adhesion. It is preferable to carry out a saponification treatment after forming the outermost layer. The saponification treatment is performed by a known method, for example, by immersing the film in an alkali solution for an appropriate time. After being immersed in the alkaline solution, it is preferable to sufficiently wash with water or neutralize the alkaline component by dipping in a dilute acid so that the alkaline component does not remain in the film.
By saponification treatment, the surface of the transparent support opposite to the side having the outermost layer is hydrophilized.

<Application method>
The optical film of the present invention can be formed by the following method, but is not limited to this method. First, a coating solution containing components for forming each layer is prepared. Next, a coating solution for forming various functional layers is applied onto the transparent support by dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating or die coating. The microgravure coating method, the wire bar coating method, and the die coating method (see US Pat. No. 2,681,294 and JP-A-2006-122889) are more preferable, and the die coating method is particularly preferable.

  Thereafter, the monomer for forming the functional layer is polymerized and cured by light irradiation or heating. Thereby, a functional layer is formed. If necessary, the functional layer can be a plurality of layers.

  Next, a coating solution for forming a low refractive index layer is applied onto the functional layer in the same manner, and is irradiated with light or heated (irradiated with ionizing radiation such as ultraviolet rays, preferably irradiated with ionizing radiation under heating. Cured) to form a low refractive index layer. In this way, the optical film of the present invention is obtained.

<Polarizing plate>
The polarizing plate is mainly composed of two protective films that protect both the front and back sides of the polarizing film. The optical film of the present invention is preferably used for at least one of the two protective films sandwiching the polarizing film from both sides. The manufacturing cost of a polarizing plate can be reduced because the optical film of the present invention also serves as a protective film. In addition, by using the optical film of the present invention as the outermost layer, reflection of external light and the like can be prevented, and a polarizing plate having excellent scratch resistance, antifouling property and the like can be obtained.

The hydrophilized surface is particularly effective for improving the adhesion with a polarizing film containing polyvinyl alcohol as a main component. In addition, the hydrophilic surface makes it difficult for dust in the air to adhere to it, making it difficult for dust to enter between the polarizing film and the optical film when bonded to the polarizing film, and is effective in preventing point defects caused by dust. It is.
The saponification treatment is preferably carried out so that the contact angle of water on the surface of the transparent support opposite to the side having the outermost layer is 40 ° or less. More preferably, it is 30 ° or less, particularly preferably 20 ° or less.

<Image display device>
The optical film of the present invention is applied to an image display device such as a liquid crystal display device (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), a cathode ray tube display device (CRT), and a surface electric field display (SED). can do. It is particularly preferably used for a liquid crystal display (LCD). Since the optical film of the present invention has a transparent support, it is used by bonding the transparent support side to the image display surface of the image display device.

  When the optical film of the present invention is used as one side of a surface protective film of a polarizing film, it is twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optically. It can be preferably used for a transmissive, reflective, or transflective liquid crystal display device in a mode such as a compensated bend cell (OCB).

  In order to describe the present invention in detail, examples will be described below, but the present invention is not limited thereto. Unless otherwise specified, “part” and “%” are based on mass.

Composition of coating solution A-1 for light scattering layer 8-30 g PET-30
Irgacure 127 3.0g
6 μm crosslinked acrylic particles (30%) 10.0 g
8μm crosslinked acrylic / styrene particles (30%) 26.6g
FP-13 0.2g
CAB 0.5g
MIBK 55.0g
MEK 25.0g

Composition of coating solution A-2 for light scattering layer 85.8 g PET-30
Irgacure 127 3.0g
6 μm crosslinked acrylic particles (30%) 10.0 g
6μm cross-linked acrylic / styrene particles (30%) 26.6g
FP-13 0.2g
CAB 0.5g
MIBK 55.0g
MEK 25.0g

Composition of coating solution A-3 for light scattering layer 8-30 g PET-30
Irgacure 127 3.0g
6 μm cross-linked acrylic / styrene particles (30%) 10.0 g
8μm crosslinked acrylic / styrene particles (30%) 26.6g
FP-13 0.2g
CAB 0.5g
MIBK 55.0g
MEK 25.0g

Composition of coating solution A-4 for light scattering layer 8-30 g PET-30
Irgacure 127 3.0g
6μm cross-linked acrylic / styrene particles (30%) 36.6g
FP-13 0.2g
CAB 0.5g
MIBK 55.0g
MEK 25.0g

Composition of coating solution A-5 for light scattering layer 8-30 g PET-30
Irgacure 127 3.0g
6 μm crosslinked acrylic particles (30%) 10.0 g
9μm cross-linked acrylic / styrene particles (30%) 26.6g
FP-13 0.2g
CAB 0.5g
MIBK 55.0g
MEK 25.0g

Composition of coating solution A-6 for light scattering layer 8-30 g PET-30
Irgacure 127 3.0g
8 μm crosslinked acrylic particles (30%) 10.0 g
8μm crosslinked acrylic / styrene particles (30%) 26.6g
FP-13 0.2g
CAB 0.5g
MIBK 55.0g
MEK 25.0g

Composition of coating solution A-7 for light scattering layer 8-30 g PET-30
Irgacure 127 3.0g
9 μm crosslinked acrylic particles (30%) 10.0 g
8μm crosslinked acrylic / styrene particles (30%) 26.6g
FP-13 0.2g
CAB 0.5g
MIBK 55.0g
MEK 25.0g

Composition of coating solution A-8 for light scattering layer 8-30 g PET-30
Irgacure 127 3.0g
10 μm crosslinked acrylic particles (30%) 10.0 g
8μm crosslinked acrylic / styrene particles (30%) 26.6g
FP-13 0.2g
CAB 0.5g
MIBK 55.0g
MEK 25.0g

Composition of coating solution A-9 for light scattering layer 8-30 g of PET-30
Irgacure 127 3.0g
11 μm crosslinked acrylic particles (30%) 10.0 g
8μm crosslinked acrylic / styrene particles (30%) 26.6g
FP-13 0.2g
CAB 0.5g
MIBK 55.0g
MEK 25.0g

Composition of coating solution A-10 for light scattering layer 8-30 g PET-30
Irgacure 127 3.0g
8 μm crosslinked acrylic particles (30%) 10.0 g
6μm melamine particles (30%) 26.6g
FP-13 0.2g
CAB 0.5g
MIBK 55.0g
MEK 25.0g

Each coating solution for the antiglare layer was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution.
The refractive index of the matrix after curing in the coating solution was 1.51.

The refractive index of the particles was as follows.
6, 8, 9, 10 μm crosslinked acrylic particles 1.49
6,8,9μm cross-linked acrylic / styrene particles 1.58
6 μm melamine particles 1.60

Composition of coating liquid L-1 for low refractive index layer Ethylenically unsaturated group-containing fluorine-containing polymer (A-1) 3.9 g
Silica dispersion A (22%) 25.0 g
Irgacure 127 0.2g
DPHA 0.4g
MEK 100.0g
MIBK 45.5g

The coating solution for the low refractive index layer was filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating solution.
The refractive index after curing of the low refractive index layer obtained by coating and curing the coating solution was 1.36.

The compounds used are shown below.
PET-30: A mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate [manufactured by Nippon Kayaku Co., Ltd.];
DPHA: a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate [manufactured by Nippon Kayaku Co., Ltd.];
6 μm cross-linked acrylic particles (30%): MIBK dispersion in which average particle size is 6.0 μm [manufactured by Soken Chemical Co., Ltd.] with a Polytron disperser at 10,000 rpm for 20 minutes)
(Cross-linked acrylic particles of other particle sizes were prepared in the same manner.);
6 μm cross-linked acrylic / styrene particles (30%): MIBK dispersion in which an average particle size of 6.0 μm [manufactured by Sekisui Co., Ltd.] was dispersed with a Polytron disperser at 10,000 rpm for 20 minutes)
(Cross-linked acrylic / styrene particles of other particle sizes were prepared in the same manner.);
6 μm melamine particles (30%): MIBK dispersion in which an average particle size of 6.0 μm is dispersed with a polytron disperser at 10,000 rpm for 20 minutes);
Irgacure 127: Polymerization initiator [Ciba Specialty Chemicals Co., Ltd.];
CAB: cellulose acetate butyrate;
Ethylenically unsaturated group-containing fluoropolymer (A-1): fluoropolymer (A-1) described in Production Example 3 of JP-A-2005-89536;

  SP-13: Fluorine-based surfactant (used after dissolving as a 10% by mass solution of MEK)

(Silica dispersion A)
Hollow silica fine particle sol (Isopropyl alcohol silica sol, average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20% by mass, silica particle refractive index 1.31, prepared by changing the size according to Preparation Example 4 of JP-A-2002-79616 ) 10 g of acryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) and 1.0 g of diisopropoxyaluminum ethyl acetate were added to and mixed with 500 g, and then 3 g of ion-exchanged water was added. After making it react at 60 degreeC for 8 hours, it cooled to room temperature and added 1.0 g of acetylacetone. While adding cyclohexanone to 500 g of this dispersion so that the content of silica was almost constant, solvent substitution by vacuum distillation was performed. There was no generation of foreign matter in the dispersion, and the viscosity when the solid content concentration was adjusted to 22% by mass with cyclohexanone was 5 mPa · s at 25 ° C. When the residual amount of isopropyl alcohol in the obtained dispersion A was analyzed by gas chromatography, it was 1.0%.

[Example 1]
Preparation of optical film samples 101-112

(1) Coating of anti-glare layer An 80 μm-thick triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Film Co., Ltd.) is unwound in roll form, and the anti-glare layer coating solution shown in Table 1 is used. In the die coating method using the slot die described in Example 1 of Japanese Patent Application Laid-Open No. 2006-122889, coating was performed under the condition of a conveyance speed of 30 m / min, drying at 60 ° C. for 150 seconds, and further oxygen concentration under a nitrogen purge. Using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 0.1% and 160 W / cm, the coating layer is cured by irradiating with an ultraviolet ray having an illuminance of 400 mW / cm ² and an irradiation amount of 100 mJ / cm ^2. It was. The coating amount was adjusted so that the film thickness of each antiglare layer was the value shown in Table 1.

(2) Coating of low refractive index layer The triacetyl cellulose film coated with the antiglare layer is unwound again, and the coating solution for the low refractive index layer is conveyed by a die coating method using the slot die. After coating at 30 m / min and drying at 90 ° C. for 75 seconds, an air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) having an oxygen concentration of 0.01 to 0.1% and 240 W / cm under a nitrogen purge was used. Then, an ultraviolet ray having an illuminance of 400 mW / cm ² and an irradiation amount of 240 mJ / cm ² was irradiated to form a low refractive index layer having a thickness of 100 nm, and wound up to prepare an antiglare antireflection film.

(Saponification of optical film)
After coating, the sample was subjected to the following treatment. A 1.5 mol / L aqueous sodium hydroxide solution was prepared and kept at 55 ° C. A 0.01 mol / L dilute sulfuric acid aqueous solution was prepared and kept at 35 ° C. The produced optical film was immersed in the aqueous sodium hydroxide solution for 2 minutes, and then immersed in water to sufficiently wash away the aqueous sodium hydroxide solution. Subsequently, after being immersed in the above-mentioned dilute sulfuric acid aqueous solution for 1 minute, it was immersed in water to sufficiently wash away the dilute sulfuric acid aqueous solution. Finally, the sample was thoroughly dried at 120 ° C.
In this way, saponified optical films (invention samples 101 to 115 and comparative samples 121 to 133) were produced.

(Preparation of polarizing plate)
Example 1 of a triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Film Co., Ltd.) having a thickness of 80 μm, which was immersed in a 1.5 mol / L, 55 ° C. NaOH aqueous solution for 2 minutes and then neutralized and washed with water. A polarizing plate was prepared by adhering and protecting both sides of a polarizing film prepared by adsorbing iodine to polyvinyl alcohol and stretching the film on each sample of the present invention sample (saponified). In this way, a polarizing plate was produced.

(Evaluation of optical film and polarizing plate)
About these obtained optical film samples, the following items were evaluated. The results are shown in Table 1.

(1) Evaluation of reproducibility of surface shape The surface roughness Ra and the average mountain valley distance Sm were measured using a sample applied 2 hours after the preparation of the coating solution for the antiglare layer, and defined as Ra and Sm of each sample. Further, Ra26 and Sm26 were obtained by performing the same measurement on the sample applied 26 hours after the preparation of the coating solution. ΔRa = Ra26−Ra and ΔSm = Sm26−Sm were calculated and used as indices of surface shape stability before and after the coating solution was aged. Ra and Sm were measured as follows.

Surface roughness (Ra):
According to JIS-B0601, the centerline average roughness (Ra) (μm) was measured using a surf coder MODEL SE-3F manufactured by Kosaka Laboratory.

Average mountain valley distance Sm:
The average value Sm (μm) of the intervals of one mountain valley was obtained from the intersection where the roughness curve intersected the center line according to JIS-B0601. The measuring device used was Kosaka Laboratory Co., Ltd., Surfcoder MODEL SE-3F. In addition, the notation “-” in the table indicates that measurement is impossible.

(2) Haze [1] The total haze value (H) of the obtained optical film is measured according to JIS-K7136.
[2] A few drops of silicone oil are added to the front and back surfaces of the optical film, and two glass plates with a thickness of 1 mm (micro slide glass product number S9111, made by MATSUNAMI) are sandwiched from the front and back sides to completely separate the two glasses. The plate was adhered to the obtained optical film, the haze was measured in a state where the surface haze was removed, and the value obtained by subtracting the haze measured by sandwiching only silicone oil between two separately measured glass plates was measured. Calculated as internal haze (Hi).
[3] A value obtained by subtracting the internal haze (Hi) calculated in [2] from the total haze (H) measured in [1] above was calculated as the surface haze (Hs) of the film.

(3) Average reflectivity The back side of the film was treated with black ink after sanding the back side of the film, and the back side was removed using a spectrophotometer (manufactured by JASCO Corp.). The spectral reflectance was measured in the wavelength region of 380 to 780 nm. The arithmetic average value of the integrated reflectance of 450 to 650 nm was used for the result.

(4) Blackening feeling A sensory evaluation was performed on the feeling of blackening on a liquid crystal display device in which a polarizing plate having an optical film attached to the viewing side surface was disposed. The evaluation method is a method in which multiple displays are arranged in parallel and compared at the same time. From the front, the blackness when the power is turned off and the blackness (black image) when the power is turned on are compared for each film, and evaluated according to the following criteria. did. It was expressed by the standard that the stronger the blackness, the stronger the tightness of the screen.
A: Strong black and the screen looks very strong.
○: Black color is strong and the screen looks strong.
Δ: Black but gray, and the screen is not tight.
×: The color is very gray and there is no tightness on the screen.

(5) Anti-glare The entire back side of the coated surface of the obtained film is painted with black magic ink, and the exposed fluorescent lamp (8000 cd / m ² ) without louver is projected from an angle of 5 degrees, from the direction of −5 degrees. The degree of blurring of the reflected image when observed from an angle of 45 degrees and observed from a direction of -45 degrees was evaluated according to the following criteria.
◎: Fluorescent lamp outline is slightly observed at -5 degrees and -45 degrees. ◯: Fluorescent lamp outline is slightly observed at -5 degrees, but the outline is relatively clear at -45 degrees. I understand.
Δ: The outline of the fluorescent lamp can be seen relatively clearly even at −5 degrees or −45 degrees.
X: The outline of the fluorescent light is clearly visible or dazzling at -5 degrees or -45 degrees.

  The evaluation results of each sample are shown in Table 1.

  From the results shown in Table 1, the following is clear. The optical film of the present invention has desirable optical performance (average reflectance, darkening, antiglare property) as an antiglare antireflection film. It can be seen that by setting the particle size ratio of the light-transmitting particles of the antiglare layer within the range of the present invention, the values of ΔRa and ΔSm are close to zero and the surface shape is excellent in stability.

[Example 2]
80 μm-thick triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Film Co., Ltd.), which was immersed in an aqueous 1.5 mol / L, 55 ° C. NaOH solution for 2 minutes, neutralized and washed with water, Example 1 A polarizing plate was prepared by adhering and protecting both sides of a polarizing film prepared by adsorbing iodine to polyvinyl alcohol and stretching the film on each sample of the present invention sample (saponified). The polarizing plate produced in this way is a liquid crystal display device of a notebook personal computer equipped with a transmission type TN liquid crystal display device so that the light scattering layer or the low refractive index layer is the outermost surface (a polarization separation film having a polarization selection layer). A display device with extremely low background reflection and very high display quality when the polarizing plate on the viewing side of D-BEF manufactured by Sumitomo 3M Co., Ltd. is placed between the backlight and the liquid crystal cell. was gotten.

[Example 3]
As a protective film on the liquid crystal cell side of the polarizing plate on the viewing side of the transmission type TN liquid crystal cell to which each film of the sample of the present invention in Example 1 was attached, and as a protective film on the liquid crystal cell side of the polarizing plate on the backlight side, When using an optical compensation film (Wide View Film Ace, manufactured by Fuji Film Co., Ltd.), it has excellent contrast in a bright room, very wide viewing angles in the top, bottom, left and right, extremely excellent visibility, and high display quality. A liquid crystal display device was obtained.

[Example 4]
When each film of the sample of the present invention in Example 1 was bonded to the glass plate on the surface of the organic EL display device via an adhesive, reflection on the glass surface was suppressed, and a display device with high visibility was obtained. It was.

[Example 5]
Using each film of the sample of the present invention in Example 1, a polarizing plate having the optical film of the present invention on one side was prepared, and λ / on the opposite side of the polarizing plate having the optical film of the present invention. When four plates are bonded together and pasted on the glass plate on the surface of the organic EL display device so that the optical film side of the present invention is the outermost surface, the surface reflection and the reflection from the inside of the surface glass are cut off and extremely visible. High display was obtained.

Claims (11)

  An optical film having an antiglare layer on a transparent support, wherein the antiglare layer has a matrix constituting the antiglare layer and at least two kinds of translucent particles, and at least one of the translucent particles is The average particle diameter is 5.5 μm or more and 15.0 μm or less (Particle A), and at least one kind has translucent particles (Particle B) whose average particle diameter is 105% or more and 135% or less with respect to Particle A. An optical film, wherein the film thickness of the antiglare layer is 8 μm or more and 40 μm or less.   The optical film according to claim 1, wherein the refractive index of the A particles is different from that of the B particles, and the refractive index difference is 0.02 or more.   3. The optical film according to claim 1, wherein at least one of the A particles and the B particles has a refractive index of 1.54 or more and 1.70 or less, and at least one of them has a refractive index of 1.53 or less.   The haze value resulting from surface scattering is 0% or more and 10% or less, The optical film according to any one of claims 1 to 3.   The optical film according to any one of claims 1 to 4, wherein a haze value resulting from internal scattering is 10 to 90%.   The optical film according to claim 1, further comprising a layer having a refractive index lower than that of the light scattering layer.   The optical film according to claim 1, wherein the integrated reflectance is 3.0% or less.   In the polarizing plate which consists of a polarizing film and two protective films which protect both the front side and back side of this polarizing film, at least one of this protective film is an optical film in any one of Claims 1-7. A polarizing plate characterized by that.   An image display device comprising the optical film according to claim 1 or the polarizing plate according to claim 8.   A liquid crystal display device comprising the optical film according to claim 1 or the polarizing plate according to claim 8.   A method for producing an optical film having an antiglare layer on a transparent support, wherein the coating solution for the antiglare layer has a matrix constituting the antiglare layer, at least two kinds of translucent particles, and at least two kinds of solvents. At least one of the translucent particles has an average particle size of 5.5 μm to 15.0 μm (particle A), and at least one of the light transmitting particles has an average particle size of 105% to 135% with respect to the particle A. A method for producing an optical film, comprising translucent particles (particle B), wherein the film thickness of the antiglare layer after coating and curing the coating solution for the antiglare layer is 8 μm or more and 40 μm or less.