JP2005266231A - Optical film, polarizing plate, and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film where irregular reflection is reduced while keeping the function of a back coat layer, and to provide a polarizing plate and an image display device. <P>SOLUTION: In the optical film having a functional thin film layer on one side on a transparent film and having the back coat layer containing cellulose ester, particles and organic solvent as main components on the opposite side of the transparent film, the refractive index of the particles is ≤1.42 and a diameter is ≤0.2μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical film, a polarizing plate, and an image display device with little reflection unevenness.

  An optical film may be used as a protective layer for a liquid crystal monitor, a polarizing plate of a television, etc. as one of uses. In this case, when the polarizing plate is used, a saponification treatment is performed to ensure adhesion with the adhesive, and thereafter, it is bonded to the polarizer with the adhesive.

  Conventionally, a film having an actinic radiation curable resin layer (also referred to as a hard coat layer) or an antiglare layer often generates curl when cured by irradiation with actinic radiation. As a preventive measure, a solvent treatment is performed on the back surface of the hard coat layer (for example, see Patent Documents 1 and 2), or a technique for forming a backcoat layer as an anti-curl layer (also serving as an anti-blocking layer) (for example, Patent Documents). 3-5.) Etc. are disclosed.

When the present inventors used an antireflection film on the outermost surface of a liquid crystal image display device according to the above technique, while providing a backcoat layer on the back surface of the antireflection film that is one of the optical films, It was found that uneven reflection was conspicuous.
JP-A-9-20912 JP-A-9-218302 JP 2001-183528 A JP 2001-64422 A JP 2001-83327 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical film, a polarizing plate, and an image display device with little reflection unevenness while maintaining the function of a backcoat layer. .

  The above object of the present invention is achieved by the following configurations.

(Claim 1)
In an optical film having a functional thin film layer on one side of the transparent film and a back coat layer mainly composed of cellulose ester, fine particles and an organic solvent on the opposite side, the refractive index of the fine particles is 1.42 or less, and An optical film having a diameter of 0.2 μm or less.

(Claim 2)
The optical film according to claim 1, wherein the fine particles are hollow silica-based fine particles.

(Claim 3)
An optical film comprising a functional thin film layer on one side of a transparent film and a backcoat layer comprising cellulose ester, fine particles, a plasticizer (high boiling point solvent) and an organic solvent as main components on the opposite side.

(Claim 4)
The optical film according to any one of claims 1 to 3, wherein the back coat layer further contains fine particles having a diameter of 0.2 to 5 µm.

(Claim 5)
The optical film according to claim 1, wherein the transparent film is a cellulose ester film.

(Claim 6)
In an optical film having a functional thin film layer on one side of a transparent film and a back coat layer mainly composed of cellulose ester and fine particles on the opposite side, the refractive index of the fine particles is that of the cellulose ester and the transparent film. And the content of the fine particles was adjusted so that the refractive index of the backcoat layer after saponification was a value within ± 0.02 with respect to the refractive index of the transparent film. A featured optical film.

(Claim 7)
The optical film according to claim 6, wherein the fine particles are metal oxide fine particles selected from Zr, Sn, Sb, As, Zn, Nb, In, and Al.

(Claim 8)
The functional thin film layer is a hard coat layer mainly composed of an active energy ray curable resin, and an antireflection layer by optical interference provided directly or indirectly on the hard coat layer. The optical film of any one of -7.

(Claim 9)
A polarizing plate produced by saponifying the optical film according to any one of claims 1 to 7 and then bonding it with a polarizer mainly composed of polyvinyl alcohol and iodine.

(Claim 10)
An image display device using the polarizing plate according to claim 9.

  According to the present invention, it is possible to provide an optical film, a polarizing plate and an image display device with little reflection unevenness while maintaining the function of the backcoat layer.

  As a result of diligent research, the present inventor has refracted fine particles in an optical film having a functional thin film layer on one side of a transparent film and a back coat layer mainly composed of cellulose ester, fine particles and an organic solvent on the opposite side. It has been found that an optical film having a ratio of 1.42 or less and a diameter of 0.2 μm or less can provide an optical film with little reflection unevenness while maintaining the function of the backcoat layer.

  Also, an optical film having a functional thin film layer on one side of the transparent film and a back coat layer mainly composed of cellulose ester, fine particles, plasticizer (high boiling point solvent) and organic solvent on the other side, one side of the transparent film In the optical film having a functional thin film layer and a back coat layer mainly composed of cellulose ester and fine particles on the opposite side, the refractive index of the fine particles is 0.1 times the refractive index of the cellulose ester and the transparent film. By using an optical film in which the content of the fine particles is adjusted so that the refractive index of the backcoat layer is a value within ± 0.02 with respect to the refractive index of the transparent film after saponification treatment. It has been found that an optical film with little reflection unevenness can be obtained while maintaining the function of the layer.

  As a result of the study by the present inventors, the antireflection film provided with the backcoat layer by a conventional method has a difference in reflection unevenness before and after saponification to be bonded to the polarizer when making a polarizing plate. It is estimated that the back coating layer on the back surface is altered by the saponification treatment, and light reflection is increased at the interface between the transparent film substrate and the back coating layer, thereby causing uneven reflection. For this reason, when the optical film having the functional thin film layer other than the antireflection layer and the back coat layer was investigated, the same situation was observed although there was a difference in the deterioration width of the reflection unevenness. The backcoat layer comprising the composition of the present invention is considered to be capable of suppressing alteration due to saponification treatment and suppressing reflection unevenness.

  The present invention will be described in detail below.

[Transparent film]
The transparent film used as the substrate of the optical film in the present invention is not particularly limited. For example, polyester film, polyethylene film, polypropylene film, cellophane, cellulose diacetate film, cellulose acetate butyrate film, cellulose acetate phthalate film, cellulose Acetate propionate film (CAP film), cellulose triacetate, cellulose ester such as cellulose nitrate or a derivative thereof, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene film, Polycarbonate film, norbornene resin film, polymethylpentene film Polyether ketone film, polyether sulfone film, polysulfone film, polyether ketone imide film, polyamide film, fluororesin film, nylon film, polymethyl methacrylate film, acrylic film, polyarylate film or polylactic acid film However, the present invention includes cellulose ester films such as cellulose triacetate film (TAC film), polycarbonate (hereinafter abbreviated as PC) film, syndiotactic polystyrene film, polyarylate film, norbornene resin system. Films and polysulfone-based films are preferred because they have no transparency, mechanical properties, and optical anisotropy. Particularly, cellulose ester films (CAP Irumu, TAC film), they are preferably used because of excellent is easy workability film-forming properties, among preferable to particularly use a TAC film.

  When the cellulose ester film is used, the cellulose ester film may be saponified before the coating layers of the present invention are applied. For example, after saponification treatment after film formation, an actinic radiation curable resin layer may be applied and further saponification treatment may be performed.

  Next, although a method for forming a TAC film will be described, CAP can also be formed in the same manner. A TAC film is generally made of a TAC flake raw material and a plasticizer dissolved in methylene chloride to form a viscous liquid, and the plasticizer is dissolved into a dope. From a extruder die, a metal such as stainless steel that rotates endlessly. It is cast on a belt (also referred to as a band), dried, peeled off from the belt in a freshly dried state, and dried from both sides by a transport device such as a roll and wound up to be manufactured. The PC film can be formed in the same manner as the TAC film.

  As the plasticizer, phosphoric acid esters or carboxylic acid esters are preferably used. Phosphoric esters include triphenyl phosphate (TPP) and tricresyl phosphate (TCP), biphenyl-diphenyl phosphate, dimethyl ethyl phosphate. Representative examples of the carboxylic acid ester include phthalic acid esters and citric acid esters. Examples of phthalic acid esters include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diethyl hexyl phthalate (DEHP), ethyl phthalyl ethyl glycolate and the like. As the citrate ester, acetyltriethyl citrate (OACTE) and acetyltributyl citrate (OACTB) are used. Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters. Phosphate ester plasticizers (TPP, TCP, biphenyl-diphenyl phosphate, dimethylethyl phosphate) and phthalate ester plasticizers (DMP, DEP, DBP, DOP, DEHP) are preferably used. In addition, a polymer compound having a weight average molecular weight of 1,000 to 100,000, such as a polyvinyl acetate copolymer, an aliphatic linear polyester, or a methyl methacrylate copolymer, can be added as a polymer plasticizer.

  Among these, triphenyl phosphate (TPP) and ethyl phthalyl ethyl glycolate are particularly preferably used. The addition amount of the plasticizer is usually 2 to 15% by mass in the film, more preferably 4 to 8% by mass.

  Also, the plasticizer can be added to the PC film.

  Furthermore, the protective film for polarizing plates excellent in light resistance can be obtained by containing a ultraviolet absorber in the TAC or PC film which is a base material useful for the present invention. Examples of ultraviolet absorbers useful in the present invention include salicylic acid derivatives (UV-1), benzophenone derivatives (UV-2), benzotriazole derivatives (UV-3), acrylonitrile derivatives (UV-4), benzoic acid derivatives (UV- 5) or an organic metal complex salt (UV-6), and (UV-1) is phenyl salicylate, 4-t-butylphenylsalicylic acid, etc., and (UV-2) is 2-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone and the like (UV-3) include 2- (2'-hydroxy-5'-methylphenyl) -benzotriazole, 2- (2'-hydroxy-3'-5 ' -Di-butylphenyl) -5-chlorobenzotriazole and the like (UV-4) is 2-ethylhexyl-2-cyano- , 3'-diphenyl acrylate, methyl-α-cyano-β- (p-methoxyphenyl) acrylate, etc. (UV-5) is resorcinol-monobenzoate, 2 ', 4'-di-t-butylphenyl -3,5-t-butyl-4-hydroxybenzoate and the like (UV-6) include nickel bis-octylphenylsulfamide, ethyl-3,5-di-t-butyl-4-hydroxybenzyl phosphate And nickel salts of these.

  Moreover, in order to improve slipperiness, fine particles (average particle diameter 0.005-0.2 micrometer), such as a silica, are 0.01-0.5 mass% in dope at the time of manufacturing these base-material transparent films. It can also be added. For example, Nippon Aerosil Co., Ltd. Aerosil 200V, Aerosil R972V, etc. can be added. The sliding property is measured with a steel ball, and it is desired that the coefficient of dynamic friction is 0.4 or less, preferably 0.2 or less.

  Although the refractive index of a transparent film changes with kinds of transparent film resin, in this invention, a preferable cellulose-ester film is 1.45-1.50.

[Back coat layer]
The present invention provides (1) an optical film having a functional thin film layer on one side of a transparent film and a back coat layer containing cellulose ester, fine particles and an organic solvent as main components on the opposite side. An optical film having a diameter of 1.42 or less and a diameter of 0.2 μm or less, (2) having a functional thin film layer on one side of a transparent film, and cellulose ester, fine particles, plasticizer (on the other side) A high-boiling solvent) and an optical film having a backcoat layer mainly composed of an organic solvent, or (3) a functional thin film layer on one side of a transparent film, and cellulose ester and fine particles on the opposite side. In an optical film having a back coat layer as a main component, the refractive index of the fine particles is more than 0.1 from the refractive index of the cellulose ester and the transparent film. Refractive index of the backcoat layer after saponification treatment is an optical film characterized in that to adjust the content of the fine particles so that the value within ± 0.02 relative refractive index of the transparent film.

(Cellulose ester)
In the present invention, it is necessary to use a cellulose ester as one of the coating compositions for the backcoat layer (binder). As the cellulose ester, cellulose ester resins such as nitrocellulose, cellulose acetate propionate, diacetyl cellulose, cellulose acetate butyrate, and cellulose acetate propionate resin can be used. Of these, diacetylcellulose is particularly preferred.

  Other binders include, for example, vinyl chloride / vinyl acetate copolymer, vinyl chloride resin, vinyl acetate resin, copolymer of vinyl acetate and vinyl alcohol, partially hydrolyzed vinyl chloride / vinyl acetate copolymer, vinyl chloride / chloride. Vinyl polymers such as vinylidene copolymer, vinyl chloride / acrylonitrile copolymer, ethylene / vinyl alcohol copolymer, chlorinated polyvinyl chloride, ethylene / vinyl chloride copolymer, ethylene / vinyl acetate copolymer Polymers, copolymers of maleic acid and / or acrylic acid, acrylate copolymers, acrylonitrile / styrene copolymers, chlorinated polyethylene, acrylonitrile / chlorinated polyethylene / styrene copolymers, methyl methacrylate / butadiene / styrene Copolymer, acrylic resin, polyvinyl chloride Rubber resins such as ruacetal resin, polyvinyl butyral resin, polyester polyurethane resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, polyether resin, polyamide resin, amino resin, styrene / butadiene resin, butadiene / acrylonitrile resin, silicone Resin, fluorine resin and the like can be used in combination.

  As acrylic resins, Acrypet MD, VH, MF, V (manufactured by Mitsubishi Rayon Co., Ltd.), Hyperl M-4003, M-4005, M-4006, M-4202, M-5000, M-5001, M-4501 ( Manufactured by Negami Kogyo Co., Ltd.), Dialnal BR-50, BR-52, BR-53, BR-60, BR-64, BR-73, BR-75, BR-77, BR-79, BR-80, BR- 82, BR-83, BR-85, BR-87, BR-88, BR-90, BR-93, BR-95, BR-100, BR-101, BR-102, BR-105, BR-106, Acrylic and methacrylic monomers such as BR-107, BR-108, BR-112, BR-113, BR-115, BR-116, BR-117, BR-118, etc. (manufactured by Mitsubishi Rayon Co., Ltd.) Various homopolymers and copolymers such as to produce a charge is preferably used.

(Fine particles)
A back coat layer is provided on the surface opposite to the side on which the functional thin film layer of the optical film of the present invention is provided. The back coat layer is provided in order to correct curling caused by providing a hard coat layer or other layers. That is, the degree of curling can be balanced by imparting the property of being rounded with the surface on which the backcoat layer is provided facing inward. In the optical film of the present invention, the back coat layer is preferably applied also as an anti-blocking layer, and fine particles are added to the back coat layer coating composition to provide an anti-blocking function. These fine particles have a refractive index of 1.42 or less, preferably 0.1 or more apart from those of the cellulose ester and the transparent film, and preferably have a diameter of 0.2 μm or less.

  The fine particles are preferably metal oxide fine particles selected from Zr, Sn, Sb, As, Zn, Nb, In, and Al. These metal oxide fine particles are conductive, and by imparting antistatic properties, they contribute to uniform film thickness application in the process of transporting and applying a functional thin film layer described later at high speed, and as a result suppress uneven reflection. To do.

  Furthermore, it is also preferable to contain fine particles having a diameter of 0.2 to 5 μm in order to enhance the blocking prevention effect.

  These fine particles added to the back coat layer include, as examples of inorganic compounds, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, oxidized Mention may be made of tin, indium oxide, zinc oxide, ITO, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Fine particles containing silicon are preferred from the viewpoint of low haze, and particularly silicon dioxide, especially hollow silica fine particles described later.

  These fine particles are commercially available under the trade names of, for example, Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, and TT600 (manufactured by Nippon Aerosil Co., Ltd.). . Zirconium oxide fine particles are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used. Examples of the polymer fine particles include silicone resin, fluororesin, and acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.) It is marketed by name and can be used.

  Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large anti-blocking effect while keeping haze low.

  The refractive index of the cellulose ester (approximately 1.45 to 1.50), the refractive index of the transparent film, and the addition amount of fine particles separated by 0.1 or more to the backcoat layer are adjusted, and the refraction of the backcoat layer after saponification treatment It is preferable to adjust the refractive index so as to be a value within ± 0.02 with respect to the refractive index of the transparent film. For example, if the transparent film is a cellulose triacetate resin film (refractive index 1.49), hollow silica-based fine particles having a refractive index of 1.28 are added to the backcoat layer (lowering the refractive index) and after saponification treatment When the refractive index of the backcoat layer is adjusted to a value within 1.49 ± 0.02, and the transparent film is a polyethylene terephthalate film (refractive index 1.59), titanium oxide having a refractive index of 2.76 Fine particles are added to the backcoat layer (increasing the refractive index) so that the refractive index of the backcoat layer after the saponification treatment is adjusted to a value within 1.59 ± 0.02.

  The fine particles contained in the backcoat layer are preferably from 0.1 to 50% by weight, and preferably from 0.1 to 10% by weight, based on the binder. When the back coat layer is provided, the increase in haze is preferably 1% or less, more preferably 0.5% or less, and particularly preferably 0.0 to 0.1%.

(Plasticizer)
In the present invention, a plasticizer is preferably used as one of the coating compositions for the backcoat layer. As the plasticizer, the plasticizer described in the section of the transparent film can be used.

(Organic solvent)
In the present invention, it is necessary to use an organic solvent as one of the coating compositions for the backcoat layer. The organic solvent has an anti-curl function in addition to the function as a solvent. The imparting of the anti-curl function is specifically performed by applying a composition containing a solvent for dissolving or swelling a transparent film used as an optical film substrate. As an organic solvent to be used, in addition to a solvent to be dissolved or a mixture of solvents to be swollen, there may be a case where a solvent that is not dissolved is further included. Do with quantity.

  In order to enhance the curl prevention function, it is effective to increase the mixing ratio of the solvent for dissolving the solvent composition to be used or the solvent for swelling and to decrease the ratio of the solvent not to be dissolved. The mixing ratio is preferably (solvent to be dissolved or solvent to be swollen) :( solvent not to be dissolved) = 10: 0 to 1: 9.

  Examples of the solvent for dissolving or swelling the transparent film contained in such a mixed composition include dioxane, acetone, methyl ethyl ketone, N, N-dimethylformamide, methyl acetate, ethyl acetate, trichloroethylene, methylene chloride, ethylene chloride, There are tetrachloroethane, trichloroethane, chloroform and the like. Examples of the solvent that does not dissolve include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butanol, cyclohexanol, and hydrocarbons (toluene, xylene).

  These coating compositions are preferably applied to the surface of the transparent film with a wet film thickness of 1 to 100 μm using a gravure coater, dip coater, reverse coater, wire bar coater, die coater, spray coating, ink jet coating or the like. In particular, the thickness is preferably 5 to 30 μm.

  The order in which the backcoat layer is applied may be before or after the transparent film hardcoat layer is applied, but when the backcoat layer also serves as an anti-blocking layer, it is preferably applied first. Further, the back coat layer can be applied in two or more times.

[Functional thin film layer]
The antireflection film of the present invention is also suitable for forming various functional layers by coating or plasma CVD, particularly atmospheric pressure plasma treatment, and these impart various functions to the optical film of the present invention. Useful for. As a result, an antireflection layer (low refractive index layer, high refractive index layer, medium refractive index layer), transparent conductive layer, antistatic layer, antifouling layer, etc. provided directly or indirectly on the hard coat layer are further formed. be able to.

[Hard coat layer]
The hard coat layer of the optical film of the present invention uses an active ray curable resin as a main component. Therefore, hereinafter, the hard coat layer is also referred to as an actinic radiation curable resin layer.

(Actinic radiation curable resin)
The actinic radiation curable resin layer refers to a layer mainly composed of a resin that cures through a crosslinking reaction or the like by irradiation with actinic rays such as ultraviolet rays or electron beams. As the actinic radiation curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and an actinic radiation curable resin layer is formed by curing by irradiation with actinic radiation such as ultraviolet rays or electron beams. The Typical examples of the actinic radiation curable resin include an ultraviolet curable resin and an electron beam curable resin, and a resin curable by ultraviolet irradiation is preferable.

  Examples of the ultraviolet curable resin include urethane acrylate resins, polyester acrylate resins, epoxy acrylate resins, polyol acrylate resins, and epoxy resins as acrylate resin resins. In the present invention, an acrylate resin resin is preferably used.

  Acrylic urethane-based resins generally include 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as acrylate including acrylate) to products obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer. Can be easily obtained by reacting an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate. For example, those described in JP-A-59-151110 can be used.

  For example, a mixture of 100 parts Unidic 17-806 (Dainippon Ink Co., Ltd.) and 1 part Coronate L (Nihon Polyurethane Co., Ltd.) is preferably used.

  Examples of UV curable polyester acrylate resins include those which are easily formed when 2-hydroxyethyl acrylate and 2-hydroxy acrylate monomers are generally reacted with polyester polyols. JP-A-59-151112 Can be used.

  Specific examples of the ultraviolet curable epoxy acrylate resin include an epoxy acrylate as an oligomer, a reactive diluent and a photoreaction initiator added thereto, and reacted to form an oligomer. Those described in US Pat. No. 105738 can be used.

  Specific examples of UV curable polyol acrylate resins include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, etc. Can be mentioned.

  Specific examples of the photoreaction initiator of these ultraviolet curable resins include benzoin and its derivatives, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof. You may use with a photosensitizer. The photoinitiator can also be used as a photosensitizer. In addition, when using an epoxy acrylate photoinitiator, a sensitizer such as n-butylamine, triethylamine, or tri-n-butylphosphine can be used. The photoreaction initiator or photosensitizer used in the ultraviolet curable resin composition is 0.1 to 15 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the composition.

  Examples of the resin monomer may include general monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, cyclohexyl acrylate, vinyl acetate, and styrene as monomers having one unsaturated double bond. In addition, monomers having two or more unsaturated double bonds include ethylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, 1,4-cyclohexane diacrylate, 1,4-cyclohexyldimethyl adiacrylate, and the above-mentioned trimethylolpropane. A triacrylate, a pentaerythritol tetraacryl ester, etc. can be mentioned.

  Examples of commercially available ultraviolet curable resins that can be used in the present invention include ADEKA OPTMER KR / BY series: KR-400, KR-410, KR-550, KR-566, KR-567, BY-320B (Asahi Denka ( Co., Ltd.); Koeihard A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T-102, D-102, NS -101, FT-102Q8, MAG-1-P20, AG-106, M-101-C (manufactured by Guangei Chemical Co., Ltd.); Seika Beam PHC2210 (S), PHC X-9 (K-3), PHC2213, DP -10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, SCR900 (manufactured by Dainichi Seika Kogyo Co., Ltd.) KRM7033, KRM7039, KRM7130, KRM7131, UVECRYL29201, UVECRYL29202 (manufactured by Daicel UCB Corporation); RC-5015, RC-5016, RC-5020, RC-5031, RC-5100, RC-5102, RC-5120 RC-5122, RC-5152, RC-5171, RC-5180, RC-5181 (manufactured by Dainippon Ink & Chemicals, Inc.); 340 clear (manufactured by China Paint Co., Ltd.); Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (Sanyo Chemical Industries, Ltd.); SP -1509, SP-1507 (manufactured by Showa Polymer Co., Ltd.); RCC-15C (manufactured by Grace Japan Co., Ltd.), Aronix M-6100, M-8030, M-8060 (manufactured by Toagosei Co., Ltd.), etc. Can be selected as appropriate.

  Examples of specific compounds include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, and the like. .

(Fine particles)
The hard coat layer thus obtained preferably contains metal oxide fine particles in order to adjust the scratch resistance, slipperiness and refractive index.

  As the metal oxide fine particles, metal oxide fine particles selected from Ti, Zr, Sn, Sb, As, Zn, Nb, In, and Al are preferable. Specifically, silicon oxide, titanium oxide, aluminum oxide, oxide Tin, indium oxide, ITO (indium tin oxide), ATO (antimony doped tin oxide), zinc oxide, zirconium oxide, magnesium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated silica Mention may be made of calcium acid, aluminum silicate, magnesium silicate and calcium phosphate. In particular, zirconium oxide, ITO, ATO or the like is preferably used.

  It is preferable that the hard coat layer is composed of two or more layers, and the metal oxide fine particles are contained in any one of the layers.

  Organic fine particles may also be included. Examples of the organic fine particles include polymethacrylic acid methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder, silicon resin powder, polystyrene resin powder, polycarbonate resin powder, benzoguanamine. Resin powder, melamine resin powder, polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, or polyfluorinated ethylene resin powder. Particularly preferred are cross-linked polystyrene particles (for example, SX-130H, SX-200H, SX-350H, manufactured by Soken Chemical) and polymethyl methacrylate-based particles (for example, MX150, MX300, manufactured by Soken Chemical).

  The average particle size of these fine particle powders is preferably 0.005 to 5 μm, and particularly preferably 0.01 to 4 μm. Moreover, it is preferable to contain 2 or more types of microparticles | fine-particles from which a particle size differs. The proportion of the ultraviolet curable resin composition and the fine particles is desirably blended so as to be 0.1 to 30 parts by mass with respect to 100 parts by mass of the resin composition.

  The hard coat layer is a clear hard coat layer having a center line average roughness (Ra) defined by JIS B 0601 of 0.001 to 0.1 μm, or an antiglare layer having Ra of about 0.1 to 1 μm. It is preferable that The center line average roughness (Ra) is preferably measured by an optical interference type surface roughness measuring instrument, and can be measured, for example, using a non-contact surface fine shape measuring device WYKO NT-2000 manufactured by WYKO.

  The refractive index of the hard coat layer according to the present invention is preferably 1.57 to 2.00 from the viewpoint of optical design for obtaining a low reflective film. The refractive index of the hard coat layer can be adjusted depending on the refractive index and content of the fine particles to be added or the inorganic binder. To increase the refractive index, titanium oxide and Ti, Zr, Sn, Sb, As, Zn, Nb, In Metal oxide fine particles selected from Al are preferred.

  The thickness of the hard coat layer is preferably 1 to 20 μm and more preferably 1.5 to 10 μm from the viewpoint of imparting sufficient durability and impact resistance.

  An adhesive layer and an adhesive layer may be provided between the transparent film and the hard coat layer. In this case, the film thickness should be 0.1 μm or less so as not to obstruct the effect of the present invention. Flame treatment, corona discharge, and plasma processing may be performed as pretreatment for applying the hard coat layer on the support. These hard coat layer layers can be coated by a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, and an ink jet method.

As a light source for curing an ultraviolet curable resin by a photocuring reaction to form a cured film layer, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 5 to 100 mJ / cm ² , and particularly preferably 20 to 80 mJ / cm ² .

  Moreover, when irradiating actinic radiation, it is preferable to carry out while applying tension | tensile_strength in the conveyance direction of a film, More preferably, it is performing applying tension | tensile_strength also in the width direction. The tension to be applied is preferably 30 to 300 N / m. The method for applying the tension is not particularly limited, and the tension may be applied in the conveying direction on the back roll, or the tension may be applied in the width direction or the biaxial direction by a tenter. This makes it possible to obtain a film with further excellent flatness.

  The ultraviolet curable resin layer composition coating solution may contain a solvent, or may be appropriately contained and diluted as necessary. Examples of the organic solvent contained in the coating liquid include hydrocarbons (toluene, xylene), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone), An ester (methyl acetate, ethyl acetate, methyl lactate), glycol ethers, and other organic solvents can be appropriately selected, or a mixture thereof can be used. Propylene glycol monoalkyl ether (1 to 4 carbon atoms of the alkyl group) or propylene glycol monoalkyl ether acetate ester (1 to 4 carbon atoms of the alkyl group) is 5% by mass or more, more preferably 5 to 80%. It is preferable to use the organic solvent containing at least mass%.

  In addition, it is particularly preferable to add a silicon compound to the ultraviolet curable resin layer composition coating solution. For example, polyether-modified silicone oil is preferably added. The number average molecular weight of the polyether-modified silicone oil is, for example, 1,000 to 100,000, preferably 2,000 to 50,000. When the number average molecular weight is less than 1,000, the coating film is dried. On the contrary, when the number average molecular weight exceeds 100,000, it tends to be difficult to bleed out on the surface of the coating film.

  Commercially available silicon compounds include DKQ8-779 (trade name, manufactured by Dow Corning), SF3771, SF8410, SF8411, SF8419, SF8421, SF8428, SH200, SH510, SH1107, SH3749, SH3771, BX16-034, SH3746, SH3749, SH8400, SH3771M, SH3772M, SH3773M, SH3775M, BY-16-837, BY-16-839, BY-16-869, BY-16-870, BY-16-004, BY-16-891, BY-16 872, BY-16-874, BY22-008M, BY22-012M, FS-1265 (above, product names manufactured by Toray Dow Corning Silicone), KF-101, KF-100T, KF351, KF3 2, KF353, KF354, KF355, KF615, KF618, KF945, KF6004, Silicone X-22-945, X22-160AS (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), XF3940, XF3949 (trade name, manufactured by Toshiba Silicone Co., Ltd.) ), Disparon LS-009 (manufactured by Enomoto Kasei Co., Ltd.), Granol 410 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.), TSF4440, TSF4441, TSF4445, TSF4446, TSF4452, TSF4460 (manufactured by GE Toshiba Silicone), BYK-306, BYK- 330, BYK-307, BYK-341, BYK-344, BYK-361 (manufactured by BYK-Japan) L series (for example, L7001, L-7006, L-7604, L-9000) manufactured by Nippon Unicar Co., Ltd. Y Over's, FZ series (FZ-2203, FZ-2206, FZ-2207) and the like, are preferably used.

  These components enhance the applicability to the substrate and the lower layer. When added to the outermost surface layer of the laminate, it not only improves the water repellency, oil repellency and antifouling properties of the coating film, but also exhibits an effect on the scratch resistance of the surface. These components are preferably added in a range of 0.01 to 3% by mass with respect to the solid component in the coating solution.

  As a method for applying the ultraviolet curable resin composition coating solution, the above-described methods can be used. The coating amount is suitably 1 to 40 μm as a wet film thickness, and preferably 3 to 20 μm. The dry film thickness is 1 to 20 μm, preferably 1.5 to 10 μm as described above.

The ultraviolet curable resin composition is preferably irradiated with ultraviolet rays during or after coating and drying, and the irradiation time for obtaining the necessary irradiation amount of active rays is preferably about 0.1 seconds to 1 minute, and is cured by ultraviolet rays. From the viewpoint of the curing efficiency or work efficiency of the functional resin, 0.1 to 10 seconds is more preferable. Moreover, it is preferable that the illuminance of these active ray irradiation parts is 50-150 mW / m < ² >. When two layers of hard coat layers are applied, it is preferable to irradiate with ultraviolet rays in the state of being stacked.

(Low refractive index layer)
The optical film of the present invention has a low refractive index layer on the hard coat layer directly or via other optical layers such as a medium refractive index layer and a high refractive index layer. The low refractive index layer is preferably provided directly on the hard coat layer.

  The low refractive index layer preferably contains hollow silica-based fine particles having an outer shell layer, which will be described later, or porous or hollow inside, or a fluorine-based resin. It is preferable that the hollow silica-based fine particles and the alkoxysilane compound are the main components.

  The low refractive index layer can be formed by coating by dispersing a metal oxide powder in a binder resin dissolved in a solvent, coating and drying, a method using a polymer having a crosslinked structure as a binder resin, Examples include a method of forming a layer by containing a saturated monomer and a photopolymerization initiator and irradiating with actinic radiation.

  In the present invention, an antireflection layer is provided on a transparent film provided with a hard coat layer, and at least one of the antireflection layers is a low refractive index layer.

  Although the structure of a preferable optical film is shown below, it is not limited to these.

Back coat layer / transparent film / hard coat layer / low refractive index layer Back coat layer / transparent film / hard coat layer / high refractive index layer / low refractive index layer Back coat layer / transparent film / hard coat layer / medium refractive index layer / High refractive index layer / Low refractive index layer Back coat layer / Transparent film / Antistatic layer / Hard coat layer / Low refractive index layer Back coat layer / Transparent film / Antistatic layer / Hard coat layer / High refractive index layer / Low Refractive index layer Back coat layer / Transparent film / Antistatic layer / Hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer Back coat layer / Transparent film / Anti-glare hard coat layer / Low refractive index layer Back coat layer / transparent film / anti-glare hard coat layer / high refractive index layer / low refractive index layer Back coat layer / transparent film / anti-glare hard coat layer / medium refractive index layer / high refractive index layer / low bending Index layer Backcoat layer / Transparent film / Antistatic layer / Anti-glare hard coat layer / Low refractive index layer Back coat layer / Transparent film / Antistatic layer / Anti-glare hard coat layer / High refractive index layer / Low refractive index Layer Back coat layer / Transparent film / Antistatic layer / Anti-glare hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer The medium refractive index layer and high refractive index layer will be described later.

(Hollow silica fine particles)
A hollow silica-based fine particle having an outer shell layer and having a porous or hollow inside, which is preferably used for the low refractive index layer and the backcoating layer, will be described.

  The hollow silica fine particles having an outer shell layer and porous inside are composite silica fine particles composed of porous particles and a coating layer provided on the surface of the porous particles. The hollow silica-based fine particles are hollow silica-based fine particles having a cavity inside and filled with a solvent, a gas, or a porous substance. Note that the low refractive index layer only needs to contain one of these particles, or may contain both.

  Note that the cavity particles are particles having a cavity inside, and the cavity is surrounded by a particle wall. The cavity is filled with contents such as a solvent, a gas or a porous substance used at the time of preparation. It is desirable that the average particle diameter of such silica-based fine particles is in the range of 5 to 300 nm, preferably 10 to 200 nm. The silica-based fine particles used are appropriately selected according to the thickness of the transparent film to be formed, and are in the range of 2/3 to 1/10 of the film thickness of the transparent film such as the low refractive index layer to be formed. Is desirable. These silica-based fine particles are preferably used in a state of being dispersed in an appropriate medium in order to form a low refractive index layer. As the dispersion medium, water, alcohol (for example, methanol, ethanol, isopropyl alcohol), ketone (for example, methyl ethyl ketone, methyl isobutyl ketone), and ketone alcohol (for example, diacetone alcohol) are preferable.

  The thickness of the coating layer of the composite particles or the thickness of the particle walls of the hollow particles is desirably in the range of 1 to 20 nm, preferably 2 to 15 nm. In the case of composite particles, if the thickness of the coating layer is less than 1 nm, the particles may not be completely covered, and it is easy to use a silicate monomer or oligomer having a low polymerization degree, which is a coating liquid component described later. In some cases, the composite particles enter the inside of the composite particles and the internal porosity is reduced, so that the effect of the low refractive index cannot be sufficiently obtained. When the thickness of the coating layer exceeds 20 nm, the silicic acid monomer and oligomer do not enter the inside, but the porosity (pore volume) of the composite particles is lowered and the effect of low refractive index is sufficiently obtained. It may not be possible. In the case of hollow particles, if the particle wall thickness is less than 1 nm, the particle shape may not be maintained, and even if the thickness exceeds 20 nm, the effect of low refractive index may not be sufficiently exhibited. .

The coating layer of the composite particles or the particle wall of the hollow particles is preferably composed mainly of silica. The coating layer of the composite particle or the particle wall of the hollow particle may contain a component other than silica, specifically, Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO _2. CeO ₂ , P ₂ O ₃ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ , WO _{3 and the} like. Examples of the porous particles constituting the composite particles include those made of silica, those made of silica and an inorganic compound other than silica, and those made of CaF ₂ , NaF, NaAlF ₆ , MgF, and the like. Among these, porous particles made of a composite oxide of silica and an inorganic compound other than silica are particularly preferable. Examples of inorganic compounds other than silica include Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , P ₂ O ₃ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ , WO _{3 and the} like. 1 type or 2 types or more can be mentioned. In such porous particles, the molar ratio MOX / SiO ₂ when the silica is represented by SiO ₂ and the inorganic compound other than silica is represented by oxide (MOX) is 0.0001 to 1.0, preferably It is desirable to be in the range of 0.001 to 0.3. It is difficult to obtain porous particles having a molar ratio MOX / SiO ₂ of less than 0.0001, and even if obtained, those having a lower refractive index are not obtained. On the other hand, if the molar ratio MOX / SiO _{2 of} the porous particles exceeds 1.0, the ratio of silica decreases, so that particles having a small pore volume and a low refractive index may not be obtained.

  The pore volume of such porous particles is desirably in the range of 0.1 to 1.5 ml / g, preferably 0.2 to 1.5 ml / g. If the pore volume is less than 0.1 ml / g, particles having a sufficiently reduced refractive index cannot be obtained. If the pore volume exceeds 1.5 ml / g, the strength of the fine particles is lowered, and the strength of the resulting coating may be lowered. is there.

  In addition, the pore volume of such porous particles can be determined by a mercury intrusion method. Examples of the contents of the hollow particles include a solvent, a gas, and a porous substance used at the time of preparing the particles. The solvent may contain an unreacted particle precursor used when preparing the hollow particles, the catalyst used, and the like. Moreover, what consists of the compound illustrated by the said porous particle as a porous substance is mentioned. These contents may be composed of a single component or may be a mixture of a plurality of components.

  As a method for producing such silica-based fine particles, for example, the method for preparing composite oxide colloidal particles disclosed in paragraphs (0010) to (0033) of JP-A-7-133105 is suitably employed. Specifically, when the composite particles are composed of silica and an inorganic compound other than silica, the composite particles are manufactured from the following first to third steps.

First Step: Preparation of Porous Particle Precursor In the first step, an alkali aqueous solution of a silica raw material and an inorganic compound raw material other than silica is separately prepared in advance, or a silica raw material and an inorganic compound raw material other than silica are prepared in advance. A mixed aqueous solution is prepared, and this aqueous solution is gradually added to an aqueous alkaline solution having a pH of 10 or more while stirring according to the composite ratio of the target composite oxide to prepare a porous particle precursor.

  As the silica raw material, alkali metal, ammonium or organic base silicate is used. Sodium silicate (water glass) or potassium silicate is used as the alkali metal silicate. Examples of the organic base include quaternary ammonium salts such as tetraethylammonium salt, and amines such as monoethanolamine, diethanolamine, and triethanolamine. The ammonium silicate or the organic base silicate includes an alkaline solution obtained by adding ammonia, a quaternary ammonium hydroxide, an amine compound or the like to a silicic acid solution.

  In addition, alkali-soluble inorganic compounds are used as raw materials for inorganic compounds other than silica. Specifically, an oxo acid of an element selected from Al, B, Ti, Zr, Sn, Ce, P, Sb, Mo, Zn, W, etc., an alkali metal salt or alkaline earth metal salt of the oxo acid, ammonium And salts and quaternary ammonium salts. More specifically, sodium aluminate, sodium tetraborate, zirconyl ammonium carbonate, potassium antimonate, potassium stannate, sodium aluminosilicate, sodium molybdate, cerium ammonium nitrate, and sodium phosphate are suitable.

Although the pH value of the mixed aqueous solution changes simultaneously with the addition of these aqueous solutions, an operation for controlling the pH value within a predetermined range is not particularly required. The aqueous solution finally has a pH value determined by the type of inorganic oxide and the mixing ratio thereof. There is no restriction | limiting in particular in the addition rate of the aqueous solution at this time. Further, in the production of composite oxide particles, a dispersion of seed particles can be used as a starting material. The seed particles are not particularly limited, but inorganic oxides such as SiO ₂ , Al ₂ O ₃ , TiO ₂ or ZrO ₂ or fine particles of these composite oxides are used. Usually, these sols are used. Can do. Furthermore, the porous particle precursor dispersion obtained by the above production method may be used as a seed particle dispersion. When the seed particle dispersion is used, the pH of the seed particle dispersion is adjusted to 10 or more, and then the aqueous solution of the compound is added to the above-described alkaline aqueous solution while stirring. Also in this case, it is not always necessary to control the pH of the dispersion. In this way, when seed particles are used, it is easy to control the particle size of the porous particles to be prepared, and particles with uniform particle sizes can be obtained.

  The silica raw material and the inorganic compound raw material described above have high solubility on the alkali side. However, when both are mixed in this highly soluble pH region, the solubility of oxo acid ions such as silicate ions and aluminate ions decreases, and these composites precipitate and grow into fine particles, or seed particles. It grows on the top and particle growth occurs. Therefore, it is not always necessary to perform pH control as in the conventional method for precipitation and growth of fine particles.

The composite ratio of silica and inorganic compound other than silica in the first step is that the inorganic compound relative to silica is converted to oxide (MOx), and the molar ratio of MOx / SiO ₂ is 0.05 to 2.0, preferably It is desirable to be within the range of 0.2 to 2.0. Within this range, the pore volume of the porous particles increases as the proportion of silica decreases. However, even when the molar ratio exceeds 2.0, the pore volume of the porous particles hardly increases. On the other hand, when the molar ratio is less than 0.05, the pore volume becomes small. When preparing hollow particles, the molar ratio of MOx / SiO ₂ is preferably in the range of 0.25 to 2.0.

Second step: Removal of inorganic compound other than silica from porous particles In the second step, inorganic compounds other than silica (elements other than silicon and oxygen) are obtained from the porous particle precursor obtained in the first step. At least a portion is selectively removed. As a specific removal method, the inorganic compound in the porous particle precursor is dissolved and removed using a mineral acid or an organic acid, or is contacted with a cation exchange resin for ion exchange removal.

  The porous particle precursor obtained in the first step is a particle having a network structure in which silicon and an inorganic compound constituent element are bonded through oxygen. By removing the inorganic compound (elements other than silicon and oxygen) from the porous particle precursor in this way, porous particles having a larger porosity and a larger pore volume can be obtained. Further, if the amount of removing the inorganic oxide (elements other than silicon and oxygen) from the porous particle precursor is increased, the hollow particles can be prepared.

  In addition, prior to removing inorganic compounds other than silica from the porous particle precursor, a silicic acid solution obtained by removing the alkali metal salt of silica from the porous particle precursor dispersion obtained in the first step. Alternatively, it is preferable to form a silica protective film by adding a hydrolyzable organosilicon compound. The thickness of the silica protective film may be 0.5 to 15 nm. Even if the silica protective film is formed, the protective film in this step is porous and thin, so that it is possible to remove inorganic compounds other than silica described above from the porous particle precursor.

  By forming such a silica protective film, inorganic compounds other than silica described above can be removed from the porous particle precursor while maintaining the particle shape. Further, when forming the silica coating layer described later, the pores of the porous particles are not blocked by the coating layer, and therefore the silica coating layer described later is formed without reducing the pore volume. Can do. Note that when the amount of the inorganic compound to be removed is small, the particles are not broken, and thus it is not always necessary to form a protective film.

  When preparing hollow particles, it is desirable to form this silica protective film. When preparing the hollow particles, the inorganic compound is removed to obtain a hollow particle precursor composed of a silica protective film, a solvent in the silica protective film, and an undissolved porous solid content. When a coating layer to be described later is formed on the precursor, the formed coating layer becomes a particle wall to form hollow particles.

The amount of the silica source added for forming the silica protective film is preferably small as long as the particle shape can be maintained. If the amount of the silica source is too large, the silica protective film becomes too thick, and it may be difficult to remove inorganic compounds other than silica from the porous particle precursor. The hydrolyzable organic silicon compound used for the silica protective film formed of the general formula _{R n Si (OR ') 4} -n [R, R': an alkyl group, an aryl group, a vinyl group, such as acrylic group An alkoxysilane represented by a hydrocarbon group, n = 0, 1, 2, or 3] can be used. In particular, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane are preferably used.

  As an addition method, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of these alkoxysilane, pure water, and alcohol is added to the dispersion of the porous particles, and the alkoxysilane is hydrolyzed. The produced silicic acid polymer is deposited on the surface of the inorganic oxide particles. At this time, alkoxysilane, alcohol, and catalyst may be simultaneously added to the dispersion. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used.

  When the dispersion medium of the porous particle precursor is water alone or when the ratio of water to the organic solvent is high, a silica protective film can be formed using a silicic acid solution. When a silicic acid solution is used, a predetermined amount of the silicic acid solution is added to the dispersion, and at the same time an alkali is added to deposit the silicic acid solution on the surface of the porous particles. In addition, you may produce a silica protective film together using a silicic acid liquid and the said alkoxysilane.

Third Step: Formation of Silica Coating Layer In the third step, a hydrolyzable organosilicon compound or silicic acid solution is added to the porous particle dispersion prepared in the second step (in the case of hollow particles, a hollow particle precursor dispersion). Etc. is added to coat the surface of the particles with a polymer such as a hydrolyzable organosilicon compound or silicic acid solution to form a silica coating layer.

The hydrolyzable organic silicon compound used for the silica coating layer formed, the above-mentioned such general formula _{R n Si (OR ') 4} -n [R, R': an alkyl group, an aryl group, a vinyl group, It is preferable to use an alkoxysilane represented by a hydrocarbon group such as an acryl group, n = 0, 1, 2, or 3]. In particular, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane are preferably used.

  As an addition method, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of these alkoxysilane, pure water, and alcohol is used as a dispersion of the porous particles (in the case of hollow particles, a hollow particle precursor). In addition, the silicic acid polymer produced by hydrolyzing alkoxysilane is deposited on the surface of the porous particles (in the case of hollow particles, hollow particle precursors). At this time, alkoxysilane, alcohol, and catalyst may be simultaneously added to the dispersion. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used.

  When the dispersion medium of porous particles (cavity particle precursor in the case of hollow particles) is water alone or a mixed solvent with an organic solvent and the mixed solvent has a high ratio of water to the organic solvent, a silicate solution You may form a coating layer using. The silicic acid solution is an aqueous solution of a low silicic acid polymer obtained by dealkalizing an aqueous solution of an alkali metal silicate such as water glass by ion exchange treatment.

  The silicic acid solution is added to the dispersion of porous particles (in the case of hollow particles, hollow particle precursors), and at the same time, alkali is added to make the low-silicic acid polymer into porous particles (in the case of hollow particles, hollow particle precursors). ) Deposit on the surface. In addition, you may use a silicic acid liquid for the coating layer formation in combination with the said alkoxysilane. The addition amount of the organosilicon compound or silicic acid solution used for forming the coating layer only needs to be sufficient to cover the surface of the colloidal particles, and the finally obtained silica coating layer has a thickness of 1 to 20 nm. In such an amount, it is added in a dispersion of porous particles (in the case of hollow particles, hollow particle precursor) in a dispersion. When the silica protective film is formed, the organosilicon compound or the silicate solution is added in such an amount that the total thickness of the silica protective film and the silica coating layer is in the range of 1 to 20 nm.

  Next, the dispersion liquid of the particles on which the coating layer is formed is heat-treated. By the heat treatment, in the case of porous particles, the silica coating layer covering the surface of the porous particles is densified, and a dispersion of composite particles in which the porous particles are coated with the silica coating layer is obtained. In the case of a hollow particle precursor, the formed coating layer is densified to form hollow particle walls, and a dispersion of hollow particles having cavities filled with a solvent, gas, or porous solid content is obtained.

  The heat treatment temperature at this time is not particularly limited as long as it can close the fine pores of the silica coating layer, and is preferably in the range of 80 to 300 ° C. When the heat treatment temperature is less than 80 ° C., the fine pores of the silica coating layer may not be completely closed and densified, and the treatment time may take a long time. Further, when the heat treatment temperature exceeds 300 ° C. for a long time, fine particles may be formed, and the effect of low refractive index may not be obtained.

  The refractive index of the inorganic fine particles thus obtained is as low as less than 1.44. Such inorganic fine particles are presumed to have a low refractive index because the porosity inside the porous particles is maintained or the inside is hollow.

  The proportion of the binder resin and fine particles in the low refractive index layer is desirably blended so as to be 0.1 to 30 parts by mass with respect to 100 parts by mass of the binder resin.

(Fluorine resin)
As the binder for the low refractive index layer, a fluorine resin that is crosslinked by heat or ionizing radiation (hereinafter, also referred to as “fluorine resin before crosslinking”) is preferably used.

  Preferred examples of the fluorine-based resin before crosslinking include a fluorine-containing copolymer formed from a fluorine-containing vinyl monomer and a monomer for imparting a crosslinkable group. Specific examples of the fluorine-containing vinyl monomer unit include, for example, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3 -Dioxoles, etc.), (meth) acrylic acid partial or fully fluorinated alkyl ester derivatives (for example, Biscoat 6FM (produced by Osaka Organic Chemicals) or M-2020 (produced by Daikin)), fully or partially fluorinated vinyl ethers, etc. Is mentioned. As monomers for imparting a crosslinkable group, glycidyl methacrylate, vinyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, vinyl glycidyl ether, and other vinyl monomers having a crosslinkable functional group in advance in the molecule. , Vinyl monomers having a carboxyl group, hydroxyl group, amino group, sulfonic acid group, etc. (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, hydroxyalkyl vinyl ether, hydroxyalkyl allyl) Ether, etc.). In the latter, it is possible to introduce a crosslinked structure by adding a compound having a group that reacts with a functional group in the polymer and one or more reactive groups after copolymerization, as disclosed in JP-A-10-25388 and 10-147739. In the issue. Examples of the crosslinkable group include acryloyl, methacryloyl, isocyanate, epoxy, aziridine, oxazoline, aldehyde, carbonyl, hydrazine, carboxyl, methylol, and active methylene group. When the fluorine-containing copolymer is cross-linked by heating by a cross-linking group that reacts by heating, or a combination of an ethylenically unsaturated group and a thermal radical generator or an epoxy group and a thermal acid generator, the thermosetting type In the case of crosslinking by irradiation with light (preferably ultraviolet rays, electron beams, etc.) by a combination of an ethylenically unsaturated group and a photo radical generator, or an epoxy group and a photo acid generator, etc., it is an ionizing radiation curable type .

  Further, in addition to the above monomers, a fluorine-containing copolymer formed by using a monomer other than the fluorine-containing vinyl monomer and the monomer for imparting a crosslinkable group may be used as the fluorine-based resin before crosslinking. The monomer that can be used in combination is not particularly limited. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, 2-acrylic acid 2- Ethyl hexyl), methacrylates (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyl toluene, α-methylstyrene, etc.), vinyl ethers (methyl vinyl ether) Etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate, etc.), acrylamides (N-tertbutylacrylamide, N-cyclohexylacrylamide, etc.), methacrylamides, Ronitoriru derivatives and the like can be mentioned. In addition, it is also preferable to introduce a polyorganosiloxane skeleton or a perfluoropolyether skeleton into the fluorinated copolymer in order to impart slipperiness and antifouling properties. For example, polyorganosiloxane or perfluoropolyether having an acrylic group, methacrylic group, vinyl ether group, styryl group or the like at the terminal is polymerized with the above monomer, and polyorganosiloxane or perfluoropolyester having a radical generating group at the terminal. It can be obtained by polymerization of the above monomers with ether, reaction of a polyorganosiloxane or perfluoropolyether having a functional group with a fluorine-containing copolymer, or the like.

  The proportion of each of the above monomers used to form the fluorinated copolymer before crosslinking is preferably 20 to 70 mol%, more preferably 40 to 70 mol%, more preferably 40 to 70 mol% of the fluorinated vinyl monomer. The amount of the monomer is preferably 1 to 20 mol%, more preferably 5 to 20 mol%, and the other monomer used in combination is preferably 10 to 70 mol%, more preferably 10 to 50 mol%.

  The fluorine-containing copolymer can be obtained by polymerizing these monomers in the presence of a radical polymerization initiator by means such as solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization.

  The fluorine-based resin before crosslinking is commercially available and can be used. Examples of commercially available fluorine-based resins before crosslinking include Cytop (Asahi Glass), Teflon (R) AF (DuPont), polyvinylidene fluoride, Lumiflon (Asahi Glass), Opstar (JSR), and the like. It is done.

  The low refractive index layer containing a crosslinked fluororesin as a constituent component preferably has a dynamic friction coefficient in the range of 0.03 to 0.15 and a contact angle with water in the range of 90 to 120 degrees.

  The low refractive index layer containing a crosslinked fluororesin as a constituent component contains the silica-based fine particles described above.

(Alkoxysilane compound)
Various sol-gel materials can also be used as binders for other low refractive index layers. As such a sol-gel material, metal alcoholates (alcolates such as silane, titanium, aluminum, and zirconium), organoalkoxy metal compounds, and hydrolysates thereof can be used. In particular, alkoxysilane, organoalkoxysilane and its hydrolyzate are preferable. Examples of these include tetraalkoxysilane (tetramethoxysilane, tetraethoxysilane, etc.), alkyltrialkoxysilane (methyltrimethoxysilane, ethyltrimethoxysilane, etc.), aryltrialkoxysilane (phenyltrimethoxysilane, etc.), dialkyl. Examples thereof include dialkoxysilane and diaryl dialkoxysilane. In addition, organoalkoxysilanes having various functional groups (vinyl trialkoxysilane, methylvinyl dialkoxysilane, γ-glycidyloxypropyltrialkoxysilane, γ-glycidyloxypropylmethyl dialkoxysilane, β- (3,4-epoxy) Dicyclohexyl) ethyltrialkoxysilane, γ-methacryloyloxypropyltrialkoxysilane, γ-aminopropyltrialkoxysilane, γ-mercaptopropyltrialkoxysilane, γ-chloropropyltrialkoxysilane, etc.), perfluoroalkyl group-containing silane compounds ( For example, (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, etc.), containing fluoroalkyl ether group It is also preferable to use a run-compound. In particular, the use of a fluorine-containing silane compound is preferable in terms of lowering the refractive index of the layer and imparting water and oil repellency.

  The low refractive index layer preferably contains 5 to 50% by mass of polymer. The polymer has a function of adhering the silica-based fine particles and maintaining the structure of the low refractive index layer including voids. The amount of the polymer used is adjusted so that the strength of the low refractive index layer can be maintained without filling the voids. The amount of the polymer is preferably 10 to 30% by mass of the total amount of the low refractive index layer. In order to adhere silica-based fine particles (hereinafter also simply referred to as fine particles) with a polymer, (1) the polymer is bonded to the surface treatment agent of the fine particles, or (2) a polymer shell is formed around the fine particles as a core. Or (3) It is preferable to use a polymer as a binder between the fine particles. The polymer to be bonded to the surface treatment agent (1) is preferably the shell polymer (2) or the binder polymer (3). The polymer (2) is preferably formed around the fine particles by a polymerization reaction before preparing the coating solution for the low refractive index layer. The polymer (3) is preferably formed by adding a monomer to the coating solution for the low refractive index layer and performing a polymerization reaction simultaneously with or after the coating of the low refractive index layer. It is preferable to carry out a combination of two or all of the above (1) to (3), and to carry out a combination of (1) and (3) or (1) to (3) all of the combinations. Particularly preferred. (1) Surface treatment, (2) shell, and (3) binder will be described sequentially.

(1) Surface treatment It is preferable that the fine particles (particularly inorganic fine particles) are subjected to a surface treatment to improve the affinity with the polymer. The surface treatment can be classified into physical surface treatment such as plasma discharge treatment and corona discharge treatment, and chemical surface treatment using a coupling agent. It is preferable to carry out only chemical surface treatment or a combination of physical surface treatment and chemical surface treatment. As the coupling agent, an organoalkoxy metal compound (eg, titanium coupling agent, silane coupling agent) is preferably used. Particles when made of SiO _2, surface treatment with a silane coupling agent can be particularly effectively conducted. As a specific example of the silane coupling agent, a silane coupling agent described later is preferably used.

  The surface treatment with the coupling agent can be carried out by adding the coupling agent to the dispersion of fine particles and leaving the dispersion at a temperature from room temperature to 60 ° C. for several hours to 10 days. In order to accelerate the surface treatment reaction, inorganic acids (for example, sulfuric acid, hydrochloric acid, nitric acid, chromic acid, hypochlorous acid, boric acid, orthosilicic acid, phosphoric acid, carbonic acid), organic acids (for example, acetic acid, polyacrylic acid, Benzenesulfonic acid, phenol, polyglutamic acid), or salts thereof (eg, metal salts, ammonium salts) may be added to the dispersion.

(2) Shell The polymer forming the shell is preferably a polymer having a saturated hydrocarbon as the main chain. A polymer containing a fluorine atom in the main chain or side chain is preferred, and a polymer containing a fluorine atom in the side chain is more preferred. Polyacrylic acid esters or polymethacrylic acid esters are preferred, and esters of fluorine-substituted alcohols with polyacrylic acid or polymethacrylic acid are most preferred. The refractive index of the shell polymer decreases as the content of fluorine atoms in the polymer increases. In order to lower the refractive index of the low refractive index layer, the shell polymer preferably contains 35 to 80% by mass of fluorine atoms, and more preferably contains 45 to 75% by mass of fluorine atoms. The polymer containing a fluorine atom is preferably synthesized by a polymerization reaction of an ethylenically unsaturated monomer containing a fluorine atom. Examples of ethylenically unsaturated monomers containing fluorine atoms include fluoroolefins (eg, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole), Mention may be made of esters of fluorinated vinyl ethers and fluorine-substituted alcohols with acrylic acid or methacrylic acid.

  The polymer forming the shell may be a copolymer composed of a repeating unit containing a fluorine atom and a repeating unit not containing a fluorine atom. The repeating unit containing no fluorine atom is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer containing no fluorine atom. Examples of ethylenically unsaturated monomers that do not contain fluorine atoms include olefins (eg, ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride), acrylic acid esters (eg, methyl acrylate, ethyl acrylate, acrylic acid 2- Ethyl hexyl), methacrylic acid esters (for example, methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate), styrene and its derivatives (for example, styrene, divinylbenzene, vinyltoluene, α-methylstyrene), vinyl ether ( For example, methyl vinyl ether), vinyl esters (for example, vinyl acetate, vinyl propionate, vinyl cinnamate), acrylamide (for example, N-tertbutylacrylamide, N-cyclohexylacrylic) Amides), methacrylamide and acrylonitrile.

  When the binder polymer (3) described later is used in combination, a crosslinkable functional group may be introduced into the shell polymer to chemically bond the shell polymer and the binder polymer by crosslinking. The shell polymer may have crystallinity. When the glass transition temperature (Tg) of the shell polymer is higher than the temperature at the time of forming the low refractive index layer, it is easy to maintain microvoids in the low refractive index layer. However, if Tg is higher than the temperature at which the low refractive index layer is formed, the fine particles are not fused, and the low refractive index layer may not be formed as a continuous layer (resulting in a decrease in strength). In that case, it is desirable to use a binder polymer (3) described later in combination, and form the low refractive index layer as a continuous layer with the binder polymer. By forming a polymer shell around the fine particles, core-shell fine particles are obtained. The core-shell fine particles preferably contain 5 to 90% by volume of a core composed of inorganic fine particles, and more preferably 15 to 80% by volume. Two or more kinds of core-shell fine particles may be used in combination. Further, inorganic fine particles having no shell and core-shell particles may be used in combination.

(3) Binder The binder polymer is preferably a polymer having a saturated hydrocarbon or polyether as the main chain, and more preferably a polymer having a saturated hydrocarbon as the main chain. The binder polymer is preferably crosslinked. The polymer having a saturated hydrocarbon as the main chain is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer. In order to obtain a crosslinked binder polymer, it is preferable to use a monomer having two or more ethylenically unsaturated groups. Examples of monomers having two or more ethylenically unsaturated groups include esters of polyhydric alcohols and (meth) acrylic acid (for example, ethylene glycol di (meth) acrylate, 1,4-dichlorohexane diacrylate, pentaerythritol). Tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate), vinylbenzene and its derivatives For example, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloyl ethyl ester, 1,4-divinylcyclohexanone), vinyl sulfone (eg, divinyl sulfone), acrylamide (eg, methylene bisacrylamide) and methacrylamide Can be mentioned. The polymer having a polyether as the main chain is preferably synthesized by a ring-opening polymerization reaction of a polyfunctional epoxy compound. Instead of or in addition to the monomer having two or more ethylenically unsaturated groups, a crosslinked structure may be introduced into the binder polymer by the reaction of a crosslinkable group. Examples of crosslinkable functional groups include isocyanate groups, epoxy groups, aziridine groups, oxazoline groups, aldehyde groups, carbonyl groups, hydrazine groups, carboxyl groups, methylol groups, and active methylene groups. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane can also be used as a monomer for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. The cross-linking group is not limited to the above compound, and may be one that exhibits reactivity as a result of decomposition of the functional group. As the polymerization initiator used for the polymerization reaction and the crosslinking reaction of the binder polymer, a thermal polymerization initiator or a photopolymerization initiator is used, and the photopolymerization initiator is more preferable. Examples of photopolymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds , Fluoroamine compounds and aromatic sulfoniums. Examples of acetophenones include 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone and 2 -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone. Examples of benzoins include benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. Examples of benzophenones include benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone. Examples of phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

  The binder polymer is preferably formed by adding a monomer to the coating solution for the low refractive index layer, and at the same time as or after the coating of the low refractive index layer, by a polymerization reaction (further crosslinking reaction if necessary). Even if a small amount of polymer (for example, polyvinyl alcohol, polyoxyethylene, polymethyl methacrylate, polymethyl acrylate, diacetyl cellulose, triacetyl cellulose, nitrocellulose, polyester, alkyd resin) is added to the coating solution for the low refractive index layer Good.

  Moreover, it is preferable to add a slipping agent to the low refractive index layer or other refractive index layers of the present invention, and scratch resistance can be improved by imparting slipperiness. As the slip agent, silicon oil or a wax-like substance is preferably used. For example, a compound represented by the following general formula is preferable.

General formula R ₁ COR ₂
In the formula, R ₁ represents a saturated or unsaturated aliphatic hydrocarbon group having 12 or more carbon atoms. An alkyl group or an alkenyl group is preferable, and an alkyl group or alkenyl group having 16 or more carbon atoms is more preferable. R ₂ represents —OM ₁ group (M ₁ represents an alkali metal such as Na or K), —OH group, —NH ₂ group, or —OR ₃ group (R ₃ represents a saturated or unsaturated group having 12 or more carbon atoms. R ₂ represents a saturated aliphatic hydrocarbon group, preferably an alkyl group or an alkenyl group, and R ₂ is preferably an —OH group, —NH ₂ group, or —OR ₃ group. Specifically, higher fatty acids such as behenic acid, stearamide, and pentacoic acid, or derivatives thereof, and carnauba wax, beeswax, and montan wax containing many of these components as natural products can also be preferably used. Polyorganosiloxane as disclosed in JP-B-53-292, higher fatty acid amide as disclosed in US Pat. No. 4,275,146, JP-B 58-33541, British patent No. 927,446 or JP-A-55-126238 and 58-90633, higher fatty acid esters (fatty acids having 10 to 24 carbon atoms and 10 to 24 carbon atoms). Esters of alcohols), and higher fatty acid metal salts as disclosed in U.S. Pat. No. 3,933,516, dicarboxylic acids having up to 10 carbon atoms as disclosed in JP-A-51-37217 A polyester compound comprising an acid and an aliphatic or cycloaliphatic diol, a dicarboxylic acid disclosed in JP-A-7-13292, Mention may be made of oligo polyester or the like from the Le.

For example, the amount of slip agent to be used in the low refractive index layer is preferably ^{0.01mg / m 2 ~10mg / m 2} .

[Medium refractive index layer, High refractive index layer]
In the present invention, it is also preferable to provide a high refractive index layer between the transparent film provided with the hard coat layer and the low refractive index layer in order to reduce the reflectance. In addition, it is more preferable to provide an intermediate refractive index layer between the transparent film and the high refractive index layer in order to reduce the reflectance. The refractive index of the high refractive index layer is preferably 1.55 to 2.30, and more preferably 1.57 to 2.20. The refractive index of the middle refractive index layer is adjusted to be an intermediate value between the refractive index of the transparent film and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.55-1.80. The thickness of the high refractive index layer and the medium refractive index layer is preferably 5 nm to 1 μm, more preferably 10 nm to 0.2 μm, and most preferably 30 nm to 0.1 μm. The haze of the high refractive index layer and the medium refractive index layer is preferably 5% or less, more preferably 3% or less, and most preferably 1% or less. The strength of the high refractive index layer and the medium refractive index layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher, with a pencil hardness of 1 kg.

  Among the refractive index layers used in the present invention, the high refractive index layer was formed by applying and drying a coating solution containing a monomer, oligomer or hydrolyzate of an organic titanium compound represented by the following general formula. A layer of 55 to 2.5 is preferred.

General formula Ti (OR ¹ ) ₄
In the formula, R ¹ is preferably an aliphatic hydrocarbon group having 1 to 8 carbon atoms, preferably an aliphatic hydrocarbon group having 1 to 4 carbon atoms. Moreover, the monomer, oligomer, or hydrolyzate thereof of an organic titanium compound reacts like -Ti-O-Ti- when an alkoxide group is hydrolyzed to form a crosslinked structure, thereby forming a cured layer.

Examples of the monomer or oligomer of the organic titanium compound used in the present invention include Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (On-C ₃ H ₇ ) ₄ , Ti (O-i- _{C 3 H 7) 4, Ti} (O-n-C 4 H 9) 4, Ti (O-n-C 3 H 7) 4 2-10 mer, Ti (O-i-C 3 H 7) Preferred examples include ₄ to 10 mer of ₄ and 2 to 10 mer of Ti (On-C ₄ H ₉ ) ₄ . These can be used alone or in combination of two or more. Of these _{Ti (O-n-C 3} H 7) 4, Ti (O-i-C 3 H 7) 4, Ti (O-n-C 4 H 9) 4, Ti (O-n-C 3 H 7 ) ₄ to 10-mer and Ti (On-C ₄ H ₉ ) ₄ to 10-mer are particularly preferable.

  Among the coating solutions for the high refractive index layer used in the present invention, it is preferable to add the organic titanium compound to a solution in which water and an organic solvent described later are sequentially added. When water is added later, hydrolysis / polymerization does not proceed uniformly, and white turbidity occurs or film strength decreases. After the water and the organic solvent are added, it is preferable that they are mixed and dissolved in order to mix well.

  Further, as another method, it is also a preferred embodiment that an organic titanium compound and an organic solvent are mixed and this mixed solution is added to the mixed and stirred solution of water and the organic solvent.

Moreover, it is preferable that the quantity of water is the range of 0.25-3 mol with respect to 1 mol of organic titanium compounds. When the amount is less than 0.25 mol, hydrolysis and polymerization are not sufficiently progressed and the film strength is lowered. If it exceeds 3 moles, hydrolysis and polymerization will proceed excessively, resulting in generation of coarse TiO ₂ particles and white turbidity. Therefore, the amount of water needs to be adjusted within the above range.

  Moreover, it is preferable that the content rate of water is less than 10 mass% with respect to the coating liquid total amount. If the water content is 10% by mass or more with respect to the total amount of the coating solution, it is not preferable because the stability of the coating solution with time deteriorates and white turbidity occurs.

  Among these, the organic solvent for the high refractive index layer is preferably a water-miscible organic solvent. Examples of water-miscible organic solvents include alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc.), many Monohydric alcohols (for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.), multivalent Alcohol ethers (eg, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether) , Ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol mono Phenyl ether, propylene glycol monophenyl ether, etc.), amines (eg, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine) , Triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.), amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.), heterocyclic rings (For example, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, etc.), sulfoxides (for example, dimethyl sulfoxide, etc.), sulfones (for example, , Sulfolane and the like), urea, acetonitrile, acetone and the like, and alcohols, polyhydric alcohols, and polyhydric alcohol ethers are particularly preferable. As described above, the amount of these organic solvents used may be adjusted so that the water content is less than 10% by mass relative to the total amount of the coating solution.

  The monomer, oligomer or hydrolyzate of the organic titanium compound used in the present invention preferably occupies 50.0% by mass to 98.0% by mass in the solid content contained in the coating solution. The solid content ratio is more preferably 50% by mass to 90% by mass, and further preferably 55% by mass to 90% by mass. In addition, it is also preferable to add to the coating composition a polymer of an organic titanium compound (a product obtained by crosslinking the organic titanium compound in advance by hydrolysis) or titanium oxide fine particles.

  The high refractive index layer and medium refractive index layer used in the present invention preferably include those containing metal oxide particles as fine particles and further containing a binder polymer.

  Alternatively, when the organotitanium compound hydrolyzed / polymerized by the coating liquid preparation method and the metal oxide particles are combined, the metal oxide particles and the hydrolyzed / polymerized organotitanium compound adhere firmly, and the hardness of the particles A strong coating film having the flexibility of a uniform film can be obtained.

The metal oxide particles used for the high refractive index layer and the medium refractive index layer preferably have a refractive index of 1.80 to 2.80, and more preferably 1.90 to 2.80. The mass average diameter of the primary particles of the metal oxide particles is preferably 1 to 150 nm, more preferably 1 to 100 nm, and most preferably 1 to 80 nm. The mass average diameter of the metal oxide particles in the layer is preferably 1 to 200 nm, more preferably 5 to 150 nm, still more preferably 10 to 100 nm, and more preferably 10 to 80 nm. Most preferred. The average particle diameter of the metal oxide particles is measured by a light scattering method if it is 20-30 nm or more, and by an electron micrograph if it is 20-30 nm or less. The specific surface area of metal oxide particles, as measured values by the BET method is preferably from 10 to 400 m ² / g, more preferably from 20 to 200 m ² / g, with 30 to 150 m ² / g Most preferably it is.

  Examples of the metal oxide particles include at least one selected from Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P, and S. Specific examples of the metal oxide include titanium dioxide (eg, rutile, rutile / anatase mixed crystal, anatase, amorphous structure), tin oxide, indium oxide, zinc oxide, and zirconium oxide. Of these, titanium oxide, tin oxide, and indium oxide are particularly preferable. The metal oxide particles are mainly composed of oxides of these metals, can further contain other elements, and fine particles imparted with conductivity are also preferably used. The main component means a component having the largest content (mass%) among the components constituting the particles. Examples of other elements include Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P, and S.

  The metal oxide particles are preferably surface-treated. The surface treatment can be performed using an inorganic compound or an organic compound. Examples of inorganic compounds used for the surface treatment include alumina, silica, zirconium oxide and iron oxide. Of these, alumina and silica are preferable. Examples of the organic compound used for the surface treatment include polyols, alkanolamines, stearic acid, silane coupling agents, and titanate coupling agents. Of these, a silane coupling agent is most preferable.

  Specific examples of the silane coupling agent include methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane. Methoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropyltriacetoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxy Propyltriethoxysilane, γ- (β-glycidyloxyethoxy) propyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, Examples include N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane and β-cyanoethyltriethoxysilane.

  Examples of silane coupling agents having a disubstituted alkyl group with respect to silicon include dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, and γ-glycidyloxypropylmethyldiethoxysilane. Γ-glycidyloxypropylmethyldimethoxysilane, γ-glycidyloxypropylphenyldiethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldi Ethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimeth Shishiran, .gamma.-mercaptopropyl methyl diethoxy silane, .gamma.-aminopropyl methyl dimethoxy silane, .gamma.-aminopropyl methyl diethoxy silane, methyl vinyl dimethoxy silane, and methyl vinyl diethoxy silane.

  Among these, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane having a double bond in the molecule. Γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, and γ-methacryloyloxypropylmethyldiethoxy having a disubstituted alkyl group with respect to silicon Silane, methylvinyldimethoxysilane and methylvinyldiethoxysilane are preferred, and γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxyp Particularly preferred are propyltrimethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane and γ-methacryloyloxypropylmethyldiethoxysilane.

  Two or more coupling agents may be used in combination. In addition to the silane coupling agents shown above, other silane coupling agents may be used. Other silane coupling agents include alkyl esters of orthosilicate (eg, methyl orthosilicate, ethyl orthosilicate, n-propyl orthosilicate, i-propyl orthosilicate, n-butyl orthosilicate, sec-butyl orthosilicate, orthosilicate). Acid t-butyl) and its hydrolyzate.

  The surface treatment with the coupling agent can be carried out by adding the coupling agent to the dispersion of fine particles and leaving the dispersion at a temperature from room temperature to 60 ° C. for several hours to 10 days. In order to accelerate the surface treatment reaction, inorganic acids (for example, sulfuric acid, hydrochloric acid, nitric acid, chromic acid, hypochlorous acid, boric acid, orthosilicic acid, phosphoric acid, carbonic acid), organic acids (for example, acetic acid, polyacrylic acid, Benzenesulfonic acid, phenol, polyglutamic acid), or salts thereof (eg, metal salts, ammonium salts) may be added to the dispersion.

  These silane coupling agents are preferably hydrolyzed with a necessary amount of water in advance. When the silane coupling agent is hydrolyzed, the surfaces of the organic titanium compound and the metal oxide particles described above are likely to react and a stronger film is formed. It is also preferable to add a hydrolyzed silane coupling agent to the coating solution in advance. The water used for this hydrolysis can also be used for the hydrolysis / polymerization of the organic titanium compound.

  In the present invention, the treatment may be performed by combining two or more kinds of surface treatments. The shape of the metal oxide particles is preferably a rice grain shape, a spherical shape, a cubic shape, a spindle shape or an indefinite shape. Two or more kinds of metal oxide particles may be used in the high refractive index layer or the middle refractive index layer.

  The ratio of the metal oxide particles in the high refractive index layer and the medium refractive index layer is preferably 5 to 65% by volume, more preferably 10 to 60% by volume, and still more preferably 20 to 55% by volume. is there.

  The metal oxide particles are supplied to a coating solution for forming a high refractive index layer and a medium refractive index layer in a dispersion state dispersed in a medium. As a dispersion medium for metal oxide particles, it is preferable to use a liquid having a boiling point of 60 to 170 ° C. Specific examples of the dispersion solvent include water, alcohol (eg, methanol, ethanol, isopropanol, butanol, benzyl alcohol), ketone (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), ketone alcohol (eg, diacetone alcohol). , Esters (eg, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate), aliphatic hydrocarbons (eg, hexane, cyclohexane), halogenated hydrocarbons (eg, methylene) Chloride, chloroform, carbon tetrachloride), aromatic hydrocarbons (eg, benzene, toluene, xylene), amides (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone), ethers (eg, diethyl ether, dioxane, Tiger hydrofuran), ether alcohols (e.g., 1-methoxy-2-propanol). Of these, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol are particularly preferable.

  The metal oxide particles can be dispersed in the medium using a disperser. Examples of the disperser include a sand grinder mill (eg, a bead mill with pins), a high-speed impeller mill, a pebble mill, a roller mill, an attritor, and a colloid mill. A sand grinder mill and a high-speed impeller mill are particularly preferred. Further, preliminary dispersion processing may be performed. Examples of the disperser used for the preliminary dispersion treatment include a ball mill, a three-roll mill, a kneader, and an extruder.

  The high refractive index layer and medium refractive index layer used in the present invention preferably use a polymer having a crosslinked structure (hereinafter also referred to as a crosslinked polymer) as a binder polymer. Examples of the crosslinked polymer include polymers having a saturated hydrocarbon chain such as polyolefin (hereinafter collectively referred to as polyolefin), and crosslinked products such as polyether, polyurea, polyurethane, polyester, polyamine, polyamide, and melamine resin. Among them, a crosslinked product of polyolefin, polyether and polyurethane is preferred, a crosslinked product of polyolefin and polyether is more preferred, and a crosslinked product of polyolefin is most preferred. Further, it is further preferable that the crosslinked polymer has an anionic group. The anionic group has a function of maintaining the dispersion state of the inorganic fine particles, and the crosslinked structure has a function of imparting a film forming ability to the polymer and strengthening the film. The anionic group may be directly bonded to the polymer chain or may be bonded to the polymer chain via a linking group, but is bonded to the main chain as a side chain via the linking group. Is preferred.

  Examples of the anionic group include a carboxylic acid group (carboxyl), a sulfonic acid group (sulfo), and a phosphoric acid group (phosphono). Of these, sulfonic acid groups and phosphoric acid groups are preferred. Here, the anionic group may be in a salt state. The cation that forms a salt with the anionic group is preferably an alkali metal ion. Moreover, the proton of the anionic group may be dissociated. The linking group that binds the anionic group and the polymer chain is preferably a divalent group selected from —CO—, —O—, an alkylene group, an arylene group, and combinations thereof. The crosslinked polymer which is a preferable binder polymer is preferably a copolymer having a repeating unit having an anionic group and a repeating unit having a crosslinked structure. In this case, the ratio of the repeating unit having an anionic group in the copolymer is preferably 2 to 96% by mass, more preferably 4 to 94% by mass, and most preferably 6 to 92% by mass. preferable. The repeating unit may have two or more anionic groups.

  The crosslinked polymer having an anionic group may contain other repeating units (a repeating unit having neither an anionic group nor a crosslinked structure). Other repeating units are preferably a repeating unit having an amino group or a quaternary ammonium group and a repeating unit having a benzene ring. The amino group or quaternary ammonium group has a function of maintaining the dispersed state of the inorganic fine particles, like the anionic group. The benzene ring has a function of increasing the refractive index of the high refractive index layer. The amino group, the quaternary ammonium group, and the benzene ring can obtain the same effect even if they are contained in a repeating unit having an anionic group or a repeating unit having a crosslinked structure.

  In the crosslinked polymer containing a repeating unit having an amino group or a quaternary ammonium group as a constituent unit, the amino group or quaternary ammonium group may be directly bonded to the polymer chain, or may be a side chain via a linking group. May be bonded to the polymer chain, but the latter is more preferred. The amino group or quaternary ammonium group is preferably a secondary amino group, a tertiary amino group or a quaternary ammonium group, more preferably a tertiary amino group or a quaternary ammonium group. The group bonded to the nitrogen atom of the secondary amino group, tertiary amino group or quaternary ammonium group is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, still more preferably carbon number. 1 to 6 alkyl groups. The counter ion of the quaternary ammonium group is preferably a halide ion. The linking group that connects the amino group or quaternary ammonium group to the polymer chain is a divalent group selected from —CO—, —NH—, —O—, an alkylene group, an arylene group, and combinations thereof. Is preferred. When the crosslinked polymer includes a repeating unit having an amino group or a quaternary ammonium group, the ratio is preferably 0.06 to 32% by mass, more preferably 0.08 to 30% by mass, Most preferably, it is 0.1-28 mass%.

  The cross-linked polymer is prepared by blending a monomer for generating a cross-linked polymer to prepare a coating solution for forming a high refractive index layer and a medium refractive index layer, and is generated by a polymerization reaction simultaneously with or after coating of the coating solution. Is preferred. Each layer is formed with the production of the crosslinked polymer. The monomer having an anionic group functions as a dispersant for inorganic fine particles in the coating solution. The monomer having an anionic group is preferably used in an amount of 1 to 50% by mass, more preferably 5 to 40% by mass, and still more preferably 10 to 30% by mass with respect to the inorganic fine particles. The monomer having an amino group or a quaternary ammonium group functions as a dispersion aid in the coating solution. The monomer having an amino group or a quaternary ammonium group is preferably used in an amount of 3 to 33% by mass based on the monomer having an anionic group. These monomers can be made to function effectively before application of the coating liquid by a method in which a crosslinked polymer is produced by a polymerization reaction simultaneously with or after application of the coating liquid.

  As the monomer used in the present invention, a monomer having two or more ethylenically unsaturated groups is most preferable, and examples thereof include esters of polyhydric alcohol and (meth) acrylic acid (eg, ethylene glycol di ( (Meth) acrylate, 1,4-dichlorohexanediacrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol Tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester Terpolyacrylate), vinylbenzene and its derivatives (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinylsulfone (eg, divinylsulfone), acrylamide (E.g., methylenebisacrylamide) and methacrylamide. Commercially available monomers may be used as the monomer having an anionic group and the monomer having an amino group or a quaternary ammonium group. As a commercially available monomer having a commercially available anionic group, KAYAMAPMPM-21, PM-2 (manufactured by Nippon Kayaku Co., Ltd.), Antox MS-60, MS-2N, MS-NH4 (manufactured by Nippon Emulsifier Co., Ltd.) , Aronix M-5000, M-6000, M-8000 series (manufactured by Toagosei Chemical Industry Co., Ltd.), Biscote # 2000 series (manufactured by Osaka Organic Chemical Industry Co., Ltd.), New Frontier GX-8289 (Daiichi Kogyo Seiyaku) NK ester CB-1, A-SA (manufactured by Shin-Nakamura Chemical Co., Ltd.), AR-100, MR-100, MR-200 (manufactured by Eighth Chemical Industry Co., Ltd.), and the like. It is done. Examples of commercially available monomers having a commercially available amino group or quaternary ammonium group include DMAA (manufactured by Osaka Organic Chemical Industry Co., Ltd.), DMAEA, DMAPAA (manufactured by Kojin Co., Ltd.), and Bremer QA (Nippon Yushi Co., Ltd.). ) And New Frontier C-1615 (Daiichi Kogyo Seiyaku Co., Ltd.).

  For the polymerization reaction of the polymer, a photopolymerization reaction or a thermal polymerization reaction can be used. A photopolymerization reaction is particularly preferable. A polymerization initiator is preferably used for the polymerization reaction. For example, the thermal polymerization initiator mentioned later used in order to form the binder polymer of a hard-coat layer, and a photoinitiator are mentioned.

  A commercially available polymerization initiator may be used as the polymerization initiator. In addition to the polymerization initiator, a polymerization accelerator may be used. The addition amount of the polymerization initiator and the polymerization accelerator is preferably in the range of 0.2 to 10% by mass of the total amount of monomers. The coating liquid (dispersion of inorganic fine particles containing monomer) may be heated to promote polymerization of the monomer (or oligomer). Moreover, it may heat after the photopolymerization reaction after application | coating, and may additionally process the thermosetting reaction of the formed polymer.

  For the medium refractive index layer and the high refractive index layer, it is preferable to use a polymer having a relatively high refractive index. Examples of the polymer having a high refractive index include polystyrene, styrene copolymer, polycarbonate, melamine resin, phenol resin, epoxy resin, and polyurethane obtained by reaction of cyclic (alicyclic or aromatic) isocyanate and polyol. . Polymers having other cyclic (aromatic, heterocyclic, and alicyclic) groups and polymers having halogen atoms other than fluorine as substituents can also be used with a high refractive index.

  Each layer of the antireflection layer can be formed by coating by dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, micro gravure coating or extrusion coating. it can.

〔Polarizer〕
The polarizing plate of the present invention will be described.

  The polarizing plate can be produced by a general method. An optical film obtained by subjecting the optical film of the present invention to an alkali saponification treatment on the back side is bonded to at least one surface of a polarizing film prepared by immersing and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Is preferred. The optical film may be used on the other surface, or another polarizing plate protective film may be used. The polarizing plate protective film used on the other surface of the optical film of the present invention preferably has an in-plane retardation Ro of 590 nm, a phase difference of 20 to 70 nm, and Rt of 70 to 400 nm. . These can be prepared, for example, by the methods described in JP-A No. 2002-71957 and Japanese Patent Application No. 2002-155395. Alternatively, it is preferable to use a polarizing plate protective film that also serves as an optical compensation film having an optically anisotropic layer formed by aligning a liquid crystal compound such as a discotic liquid crystal. For example, the optically anisotropic layer can be formed by the method described in JP-A-2003-98348. By using it in combination with the optical film of the present invention, a polarizing plate having excellent flatness and a stable viewing angle expansion effect can be obtained.

  As the polarizing plate protective film used on the back side, KC8UX2MW, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3 (manufactured by Konica Minolta Opto Co., Ltd.) and the like are preferably used as commercially available transparent films.

  The polarizing film, which is the main component of the polarizing plate, is an element that transmits only light having a polarization plane in a certain direction. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed. As the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxially stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound. On the surface of the polarizing film, one side of the optical film of the present invention is bonded to form a polarizing plate. It is preferably bonded with a water-based adhesive mainly composed of completely saponified polyvinyl alcohol or the like.

  The polarizing plate using the conventional optical film showed reflection unevenness, but the polarizing plate using the optical film of the present invention had little reflection unevenness. In addition, even when the durability test is performed at 60 ° C. and 90% RH, the unevenness of reflection does not increase, and even a polarizing plate having an optical compensation film on the back side has good visibility even after the durability test. Could be provided.

<Image display device>
By incorporating the polarizing plate of the present invention into an image display device, various image display devices with little reflection unevenness and excellent visibility can be produced. The optical film of the present invention is preferably a reflective, transmissive, transflective LCD, or TN, STN, OCB, HAN, VA (PVA, MVA), IPS, or other driving LCD. Used. Further, the optical film of the present invention has remarkably little color unevenness in the reflected light of the antireflection layer, and has excellent flatness, and various display devices such as plasma display, field emission display, organic EL display, inorganic EL display, and electronic paper. Also preferably used. In particular, a large-screen display device with a 30-inch screen or more has the effect of less color unevenness and wavy unevenness, and eyes are not tired even during long-time viewing.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these. Unless otherwise specified, “%” in the examples represents “mass%”.

Example 1
[Preparation of optical film 1]
(1) Substrate A transparent cellulose triacetate film (film thickness 80 μm, width 1330 mm) produced as follows was used.

<Production of resin film>
(Dope composition)
Cellulose triacetate (average degree of acetylation 61.0%) 100 parts by weight Triphenyl phosphate 8 parts by weight 2- [5-Chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (t-butyl ) Phenol 1 part by weight 2-[(2H) -benzotriazol-2-yl] -4,6-di-t-pentylphenol 1 part by weight Methylene chloride 430 parts by weight Methanol 90 parts by weight The above composition is put into a sealed container. The solution was kept at 80 ° C. under pressure and dissolved completely with stirring to obtain a dope composition.

  Next, the dope composition is filtered, cooled and kept at 33 ° C., and uniformly cast on a stainless steel band. After the solvent is evaporated until peeling becomes possible, the dope composition is peeled off from the stainless steel band. The film was dried while being conveyed to obtain a film having a thickness of 80 μm.

  The surface in contact with the stainless steel band is defined as b-plane and the other surface is defined as a-plane.

  In addition, b side was used for hard-coat layer formation.

(2) Composition of hard coat layer solution The following were mixed and used.

Dipentaerythritol hexaacrylate monomer 60 parts by weight Dipentaerythritol hexaacrylate dimer 20 parts by weight More than dipentaerythritol hexaacrylate trimer 20 parts by weight Diethoxybenzophenone photoinitiator 4 parts by weight Silicone surface activity Agent 1 part by weight Methyl acetate 75 parts by weight Acetone 75 parts by weight (3) Composition of backcoat layer solution The following were mixed and used.

Acetone 32 parts by weight Ethyl acetate 50 parts by weight Isopropyl alcohol 4 parts by weight Diacetylcellulose (average degree of acetylation 2.4) 0.5 parts by weight Ultrafine silica (Aerosil 200, particle size 15 nm, refractive index 1. 44) 0.1% by mass of 2% acetone dispersion (4) Optical film production apparatus Hard coat layer applicator, active energy ray irradiator, dryer (dryer) are arranged, and back coat layer liquid applicator is installed. An optical film was prepared. In addition, all used the application machine of the slide hopper type.

  The hard coat layer was applied with a wet film thickness of 13 μm, the dry film thickness was 5 μm, and the back coat layer was applied with a wet film thickness of 13 μm.

Ultraviolet irradiation conditions: 160 mJ / cm ² was irradiated.

  Dryer drying conditions: 80 ° C. and a conveyance speed of 30 m / min.

[Preparation of optical film 2]
Optical film 2 was prepared in the same manner as in the production of optical film 1 except that cellulose triacetate used for the substrate was replaced with cellulose acetopropionate.

[Preparation of optical film 3]
An optical film 3 was prepared in the same manner as in the production of the optical film 1, except that the ultrafine silica used in the backcoat layer was replaced with the following hollow silica fine particles.

(Preparation of hollow silica fine particles)
A mixture of 100 g of silica sol having an average particle diameter of 5 nm and a SiO ₂ concentration of 20% and 1900 g of pure water was heated to 80 ° C. The pH of this reaction mother liquor was 10.5, and 9000 g of 0.98% sodium silicate aqueous solution as SiO ₂ and 9000 g of 1.02% sodium aluminate aqueous solution as Al ₂ O ₃ were simultaneously added to the mother liquor. Meanwhile, the temperature of the reaction solution was kept at 80 ° C. The pH of the reaction solution rose to 12.5 immediately after the addition and hardly changed thereafter. After completion of the addition, the reaction solution was cooled to room temperature and washed with an ultrafiltration membrane to prepare a SiO ₂ .Al ₂ O ₃ core particle dispersion with a solid concentration of 20%. (Process (a))
1700 g of pure water is added to 500 g of this core particle dispersion and heated to 98 ° C., and while maintaining this temperature, a silicate solution (SiO ₂₎ obtained by dealkalizing a sodium silicate aqueous solution with a cation exchange resin. A dispersion of core particles in which 3000 g (concentration 3.5%) was added to form a first silica coating layer was obtained. (Process (b))
Next, 1125 g of pure water was added to 500 g of the core particle dispersion formed with the first silica coating layer having a solid content of 13% by washing with an ultrafiltration membrane, and concentrated hydrochloric acid (35.5%) was further added dropwise. The pH was adjusted to 1.0 and dealumination was performed. Next, the aluminum salt dissolved in the ultrafiltration membrane was separated while adding 10 L of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water, and SiO ₂ · Al from which some of the constituent components of the core particles forming the first silica coating layer were removed. A dispersion of ₂ O ₃ porous particles was prepared (step (c)). A mixture of 1500 g of the above porous particle dispersion, 500 g of pure water, 1,750 g of ethanol, and 626 g of 28% ammonia water is heated to 35 ° C., and then 104 g of ethyl silicate (SiO ₂ 28%) is added. The surface of the porous particles on which the silica coating layer was formed was coated with a hydrolyzed polycondensate of ethyl silicate to form a second silica coating layer. Next, a dispersion of hollow silica-based fine particles having a solid content concentration of 20% was prepared by replacing the solvent with ethanol using an ultrafiltration membrane.

The thickness of the first silica coating layer of the hollow silica-based fine particles was 3 nm, the average particle size was 47 nm, MOx / SiO ₂ (molar ratio) was 0.0017, and the refractive index was 1.28. Here, the average particle diameter was measured by a dynamic light scattering method.

[Preparation of optical film 4]
In the production of the optical film 1, an optical film 4 was produced in the same manner except that 0.05 parts by mass of dioctyl phthalate (plasticizer) was further added to the backcoat layer.

[Preparation of optical film 5]
An optical film 5 was prepared in the same manner as in the production of the optical film 1 except that 0.05 parts by mass of triphenyl phosphate (plasticizer) was further added to the backcoat layer.

[Preparation of optical film 6]
In the production of the optical film 3, except that 0.05 parts by mass of dioctyl phthalate (plasticizer) and conductive SnO ₂ and 0.1 parts by mass of antimony composite fine particles (manufactured by Mitsubishi Materials Corporation) were added to the back coat layer. An optical film 6 was produced in the same manner.

[Preparation of optical film 7]
In the production of the optical film 3, the optical film 7 was produced in the same manner except that 0.1 part by mass of silica fine particles having an average particle diameter of 2 μm was further added to the backcoat layer.

[Preparation of optical film 8]
An optical film 8 was prepared in the same manner as in the production of the optical film 2 except that 0.05 parts by mass of dioctyl phthalate (plasticizer) was further added to the backcoat layer.

[Evaluation of optical film]
The produced optical film was saponified as follows.

(Saponification treatment)
One optical film and one triacetyl cellulose film cut in a longitudinal direction of 30 cm and a lateral direction of 18 cm were used as protective films, which were immersed in a 2 mol / l sodium hydroxide solution at 60 ° C. for 5 minutes, further washed with water and dried. did. The optical film had an easy-adhesion film pasted on the hard coat layer surface in advance.

  The optical film before and after the saponification treatment was coated with a matte black spray paint on the back coat layer, and illuminated with a three-wavelength fluorescent lamp from the hard coat layer side, and visually observed for the presence or absence of reflection unevenness based on the following criteria. The results are shown in Table 1.

A: Completely uniform and no unevenness including reflection unevenness ○: Level with no problem even without reflection unevenness x: Level where a certain amount of reflection unevenness is observed and causes a problem

  Table 1 shows that the optical film of the present invention has little reflection unevenness.

Example 2
About the optical film produced in Example 1, blocking property was evaluated as follows. The results are shown in Table 2.

(Evaluation of blocking properties)
The occurrence of blocking was visually evaluated according to the following criteria.

○: No blocking ○ △: There is no trace or deformation in the sample to the extent that a light peeling sound is made △: There is no deformation, but a trace remains in the sample △ ×: There is no deformation but a trace remains clearly ×: There is deformation Unevenness remains in the sample XX: Strong resistance when loosening the sample

  From Table 2, it can be seen that the optical film 7 of the present invention is particularly excellent in blocking properties.

Example 3
[Preparation of optical film 9]
In the production of the optical film 1 of Example 1, cellulose triacetate (TAC) used for the resin film is replaced with polyethylene terephthalate (PET), and the hard coat layer liquid is changed to SNAP (conductive fine particles, SbO ₂ dispersion, solid content 15%, An optical film 9 was produced in the same manner except that 100 parts by mass of CI Chemical Co., Ltd. was added.

(surface treatment)
The optical film with a hard coat is immersed in a 1.5 mol / L-NaOH aqueous solution heated to 50 ° C. for 5 minutes for alkali treatment, washed with water, and then washed in a 0.5 mass% H ₂ SO ₄ aqueous solution at room temperature for 30 minutes. It was immersed for 2 seconds to neutralize, washed with water and dried.

(Antireflection layer)
The following antireflection layer (one of functional thin film layers) was applied on the surface-treated hard coat layer.

<< Production of Medium Refractive Index Layer >>
On the hard coat layer, the following medium refractive index layer composition was applied by an extrusion coater and dried for 1 minute at 80 ° C. and 0.1 m / second. After drying, the medium refractive index layer was produced by curing by irradiating with ultraviolet rays of 130 mJ / cm ² using a high-pressure mercury lamp (80 W).

<Medium refractive index layer composition>
Titanium oxide fine particle dispersion (RTSPNB15WT% -G0, solid content 15%, manufactured by CI Chemical Industry Co., Ltd.) 270 parts by mass Tetra (n) butoxytitanium 5 parts by mass Dipentaerythritol hexaacrylate (KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd.) 40 Mass parts Irgacure 184 (manufactured by Ciba Specialty Chemicals) 10 parts by mass Linear dimethyl silicone-EO block copolymer (FZ-2207, Nihon Unicar) 1 part by mass Propylene glycol monomethyl ether 1470 parts by mass Isopropyl alcohol 2720 parts by mass Methyl ethyl ketone 490 parts by mass Part The thickness of the medium refractive index layer was 77 nm and the refractive index was 1.70.

<< Preparation of high refractive index layer >>
On the medium refractive index layer, the following high refractive index layer composition was applied by an extrusion coater and dried at 80 ° C. and 0.1 m / second for 1 minute. After drying, a high-refractive index layer was produced by curing by irradiating with ultraviolet rays of 130 mJ / cm ² using a high-pressure mercury lamp (80 W).

<High refractive index layer composition>
Titanium oxide fine particle dispersion (RTSPNB15WT% -G0, solid content 15%, manufactured by CI Chemical Industry Co., Ltd.) 530 parts by mass Tetra (n) butoxytitanium 50 parts by mass γ-methacryloxypropyltrimethoxysilane (KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.) )
10 parts by weight Linear dimethyl silicone-EO block copolymer (FZ-2207, manufactured by Nihon Unicar) 1 part by weight Propylene glycol monomethyl ether 1470 parts by weight Isopropyl alcohol 2490 parts by weight Methyl ethyl ketone 490 parts by weight The thickness of this high refractive index layer Was 80 nm and the refractive index was 1.85.

<< Production of low refractive index layer >>
On the high refractive index layer, the following low refractive index layer composition was applied by an extrusion coater and dried for 1 minute at 80 ° C. and 0.1 m / second. After drying, the film was cured by irradiating with ultraviolet rays of 130 mJ / cm ² using a high-pressure mercury lamp (80 W), and further thermally cured at 120 ° C. for 5 minutes to prepare an antireflection layer having a low refractive index layer.

<Low refractive index layer composition>
Tetraethoxysilane hydrolyzate A 103 parts by mass γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM503)
1 part by weight Linear dimethyl silicone-EO block copolymer (Nippon Unicar Co., Ltd., FZ-2207) 0.1 part by weight Hollow silica-based fine particles (see Example 1) 50 parts by weight Propylene glycol monomethyl ether 270 parts by weight Isopropyl alcohol 270 parts by weight Part (Preparation of tetraethoxysilane hydrolyzate A)
The mixture was prepared by mixing 25 g of tetraethoxysilane and 222 g of ethanol, adding 54 g of a 1.5% aqueous solution of citric acid monohydrate, and then stirring at room temperature for 3 hours.

In addition, the thickness of the low refractive index layer of this antireflection layer was 93 nm, and the refractive index was 1.44.

[Preparation of optical film 10]
In the production of the optical film 9, the ultrafine particle silica of the backcoat layer is replaced with a titanium oxide fine particle dispersion (RTSPNB15WT% -G0, solid content 15%, manufactured by CII Kasei Kogyo Co., Ltd.), and the refractive index of the backcoat layer after saponification The optical film 10 was produced in the same manner except that the amount of titanium oxide added was adjusted to 2.48 parts by mass so that the refractive index of the base film was 1.59.

[Preparation of optical film 11]
In the production of the optical film 9, the ultrafine silica of the backcoat layer is replaced with ELCOM V2504 (conductive fine particles, ITO sol, solid content 20%, manufactured by Catalyst Kasei Co., Ltd.), and the refractive index of the backcoat layer after saponification is based on Optical film 11 was produced in the same manner except that the amount of ITO added was adjusted to 2.75 so that the refractive index of the material film was the same as 1.59.

[Preparation of polarizing plate]
Polarizers 9 to 11 were produced according to the following methods using the produced optical films 9 to 11 as protective films for polarizing plates.

  A 120 μm thick polyvinyl alcohol film was immersed in an aqueous solution containing 1 part by mass of iodine, 2 parts by mass of potassium iodide, and 4 parts by mass of boric acid, and stretched 4 times at 50 ° C. to obtain a polarizing film.

  In the following steps (1) to (5), the polarizing film, the optical film, and the protective resin film were bonded together to produce a polarizing plate.

<Production method of polarizing plate>
(1) One optical film and a resin film (triacetylcellulose film) cut in a longitudinal direction of 30 cm and a lateral direction of 18 cm are used as protective films, and these are placed in a 2 mol / l sodium hydroxide solution at 60 ° C. for 2 minutes. It was immersed, further washed with water and dried. The optical film had an easy-adhesion film attached to the surface of the antireflection layer in advance.

  (2) The polarizing film having the same size as the protective resin film sample is immersed in a polyvinyl alcohol adhesive tank having a solid content concentration of 2% for 1 to 2 seconds.

  (3) The excess adhesive adhering to the polarizing film of (2) was lightly removed and placed on the surface a of the optical film treated in (1), and further treated in (1) above. The protective resin film is laminated and disposed so that the a-side of the protective resin film is in contact with the polarizing film.

(4) After applying pressure to the laminate of the polarizing film, the optical film, and the protective resin film laminated in (3) above with a hand roller, the excess adhesive and bubbles are removed from the end of the laminate. to paste together. A roller speed of about 2 m / min was applied by applying a stress of 20 to 30 N / cm ^{2 with} a hand roller.

  (5) The sample obtained in (4) is left in an oven at 80 ° C. for 2 minutes.

[Evaluation of polarizing plate]
About the produced polarizing plate, the matte black spray coating was applied to the backcoat layer, and the presence or absence of reflection unevenness was visually observed based on the following criteria by illuminating with a three-wavelength fluorescent lamp from the antireflection layer side. The results are shown in Table 3.

◎: Completely uniform and completely free of unevenness including reflection unevenness ○: Level of waste without unevenness of reflection ×: Level that causes a problem when reflection unevenness of a certain level or more is observed

  From Table 3, it can be seen that the polarizing plate of the present invention has little reflection unevenness.

[Production of liquid crystal display device]
Subsequently, the liquid crystal display devices 9-11 were produced using the polarizing plates 9-11, respectively.

  A liquid crystal panel for viewing angle measurement was produced as follows, and the characteristics as a liquid crystal display device were evaluated.

  The polarizing plates on both sides of the 15-inch display VL-150SD manufactured by Fujitsu were previously peeled off, and the above-prepared polarizing plates 9 to 11 were each stuck to the glass surface of the liquid crystal cell.

  At that time, the direction of bonding of the polarizing plate is such that the surface of the optical compensation film (retardation film) is on the liquid crystal cell side and the absorption axis is in the same direction as the polarizing plate previously bonded. The liquid crystal display devices 9 to 11 were produced. Moreover, the used polarizing plate used what was cut out from the edge part of the long optical film in which performance is easy to vary.

[Evaluation of liquid crystal display devices]
About each liquid crystal display device, the screen was set as black display and the reflection unevenness of the surface was visually evaluated according to the following criteria.

◎: Unevenness of reflected light is not known and black appears to be blurred ○: Unevenness of reflected light is slightly recognized △: Unevenness of reflected light is recognized, but there is no practical problem ×: Unevenness of reflected light Pretty worried

  From the results of Table 4, it was confirmed that the liquid crystal display device produced using the polarizing plate of the present invention had little reflection unevenness.

Claims (10)

In an optical film having a functional thin film layer on one side of the transparent film and a back coat layer mainly composed of cellulose ester, fine particles and an organic solvent on the opposite side, the refractive index of the fine particles is 1.42 or less, and An optical film having a diameter of 0.2 μm or less. The optical film according to claim 1, wherein the fine particles are hollow silica-based fine particles. An optical film comprising a functional thin film layer on one side of a transparent film and a backcoat layer comprising cellulose ester, fine particles, a plasticizer (high boiling point solvent) and an organic solvent as main components on the opposite side. The optical film according to any one of claims 1 to 3, wherein the back coat layer further contains fine particles having a diameter of 0.2 to 5 µm. The optical film according to claim 1, wherein the transparent film is a cellulose ester film. In an optical film having a functional thin film layer on one side of a transparent film and a back coat layer mainly composed of cellulose ester and fine particles on the opposite side, the refractive index of the fine particles is that of the cellulose ester and the transparent film. And the content of the fine particles was adjusted so that the refractive index of the backcoat layer after saponification was a value within ± 0.02 with respect to the refractive index of the transparent film. A featured optical film. The optical film according to claim 6, wherein the fine particles are metal oxide fine particles selected from Zr, Sn, Sb, As, Zn, Nb, In, and Al. The functional thin film layer is a hard coat layer mainly composed of an active energy ray curable resin, and an antireflection layer by optical interference provided directly or indirectly on the hard coat layer. The optical film of any one of -7. A polarizing plate produced by saponifying the optical film according to any one of claims 1 to 7 and then bonding it with a polarizer mainly composed of polyvinyl alcohol and iodine. An image display device using the polarizing plate according to claim 9.