JP2012036394A - Method for manufacturing optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition from which an antireflection film can be produced having low reflectance, neutral tone, and excellent scratch resistance, and suitable for mass production with high productivity.SOLUTION: The coating composition contains a first resin component capable of forming a cured layer having a surface free energy of 30 mN/m or less, a second resin component curable with the first resin component, first inorganic fine particles having an average particle size of 2 to 100 nm, and at least one organic solvent, wherein the first resin component and/or the second resin component have an ionization radiation curable functional group, and the coating composition can give a cured layer by curing. The coating composition in the cured layer contains the first inorganic fine particles unevenly present in a lower part of the cured layer and gives an upper layer and a lower layer having different refractive indices.

Description

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

  Anti-reflection films include liquid crystal display (LCD), plasma display panel (PDP), electroluminescence display (ELD), cathode ray tube display (CRT), field emission display (FED), surface conduction electron-emitting device display (SED). In various image display devices such as), they are arranged on the surface of a display in order to prevent a decrease in contrast due to reflection of external light or reflection of an image. Therefore, in addition to high antireflection performance, the antireflection film is required to have high transmittance, high physical strength (such as scratch resistance), chemical resistance, and weather resistance (such as moisture and heat resistance).

  As an antireflection layer (a high refractive index layer, a medium refractive index layer, a low refractive index layer, etc.) used for an antireflection film, a multilayer film obtained by laminating a transparent thin film of metal oxide has been widely used. The metal oxide transparent thin film has been usually formed by a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method, particularly a vacuum vapor deposition method which is a kind of physical vapor deposition method. However, a method for forming a transparent thin film of metal oxide by vapor deposition has low productivity and is not suitable for mass production, and a method of forming by high-productivity wet coating has been proposed.

When preparing an antireflection film by wet coating, a coating composition prepared by dissolving or dispersing a film-forming composition having a specific refractive index in a solvent is coated on a transparent support base, dried, and if necessary It is necessary to form a single-layer or multilayer thin film by curing. In the case of a single layer, a layer (low refractive index layer) having a lower refractive index than that of the substrate (support) may be formed with an optical film thickness of ¼ of the design wavelength. When lower reflection is required, a layer having a higher refractive index than the transparent support (high refractive index layer) may be formed between the substrate and the layer having a low refractive index. In order to reduce the refractive index, a mode is also proposed in which an intermediate refractive index layer having a refractive index intermediate between the transparent base material and the high refractive index layer is provided on the transparent base material side of the high refractive index layer (Patent Document 1). .
When a plurality of layers having different refractive indexes are formed, the adhesion between the two layers is low, so that the scratch resistance is reduced, and the application process is increased, so that productivity may be reduced and cost may be increased. As means for solving this problem, a technique for simultaneously forming two layers having different refractive indexes has been disclosed (see, for example, Patent Document 2 and Patent Document 3). However, further improvements such as low reflectance, neutral color, high scratch resistance, and high productivity are desired.

JP 2003-121606 A JP 2004-317734 A JP 2004-359930 A

  An object of the present invention is to provide an optical film having a low reflectance, a neutral color, excellent scratch resistance, good productivity and suitable for mass production, a coating composition capable of producing the optical film, and production thereof. In providing a method. Another object of the present invention is to provide an image display device which is prevented from being reflected and has excellent display performance.

As a result of intensive studies to solve the above-described problems, the present inventors have found that the above-described problems can be solved and the object can be achieved, and the present invention has been completed.
That is, the present invention is as follows.
[1] A first resin component capable of forming a cured layer having a surface free energy of 30 mN / m or less, a second resin component curable with the first resin component, an average particle size of 2 nm to 100 nm. A coating composition containing one inorganic fine particle and at least one organic solvent, wherein the first resin component and / or the second resin component has an ionizing radiation-curable functional group,
The coating composition is a coating composition in which a cured layer is formed by curing, and the first inorganic fine particles are unevenly distributed under the cured layer to form an upper layer and a lower layer having different refractive indexes.
[2] The coating composition according to [1], wherein the first resin component is a thermosetting or ionizing radiation curable fluorine-containing compound.
[3] The fluorine-containing compound is a compound having a silicone structure in the molecule, or having a crosslinkable group that is the same as the crosslinkable group included in the silicone compound in which the coating composition includes a silicone compound having a crosslinkable group. The coating composition according to [1] or [2].
[4] Any of [1] to [3], wherein the first inorganic fine particles are inorganic fine particles that have been surface-treated with at least one selected from a silane coupling agent, a partial hydrolyzate thereof, and a condensate thereof. The coating composition according to claim 1.
[5] The surface free energy of the second resin component is larger than the surface free energy of the first resin component, and the difference between the surface free energy of the first resin component and the surface free energy of the second resin component is The coating composition according to any one of [1] to [4], which is 5 mN / m or more.
[6] The surface free energy of the first inorganic fine particles is larger than the surface free energy of the first resin component, and the difference between the surface free energy of the first inorganic fine particles and the surface free energy of the first resin component is The coating composition according to any one of [1] to [5], which is 10 mN / m or more.
[7] The coating composition according to any one of [1] to [6], wherein the second inorganic fine particles include inorganic fine particles having a refractive index of 1.46 or less.
[8] The surface free energy of the second inorganic fine particles is smaller than the surface free energy of the first inorganic fine particles, and the difference between the surface free energy of the first inorganic fine particles and the surface free energy of the second inorganic fine particles is The coating composition according to [7], which is 5 mN / m or more.
[9] An optical film having a cured layer obtained by curing the coating composition according to any one of [1] to [8] on a transparent support.
[10] The optical film according to [9], wherein the cured layer is a low refractive index layer that is an outermost layer of the optical film and a high refractive index layer adjacent thereto.
[11] A polarizing plate having a polarizing film and two protective films protecting both the front side and the back side of the polarizing film, wherein at least one of the protective films is as described in [9] or [10] The polarizing plate which is an optical film of description.
[12] An image display device having at least one of the optical film according to [9] or [10] or the polarizing plate according to [11].
[13] A method for producing an optical film having a layer formed by curing a coating composition on a transparent support, the step of applying the coating composition according to any one of [1] to [8] And a method for producing an optical film having a drying step.
[14] The step of applying is a step of applying the coating composition together with the composition for forming a hard coat layer or the composition for forming a medium refractive index layer after feeding the transparent support, and each of the layers. The manufacturing method according to [13], in which no winding step is included between the formations of.
[15] The step of applying is a step of applying the coating composition together with the composition for forming a hard coat layer or the composition for forming a medium refractive index layer after feeding the transparent support, and the hard The production method according to the above [13] or [14], which is a step of simultaneously applying at least two of the coating layer forming composition, the medium refractive index layer forming composition, and the coating composition.
[16] The production method according to any one of [13] to [15], further including a step of curing.

According to the present invention, by using the coating composition of the present invention, a cured layer having two layers of an upper layer and a lower layer having different refractive indexes and in which the first inorganic fine particles are unevenly distributed in the lower portion of the cured layer is produced. Therefore, an optical film can be produced at low cost and high productivity. Moreover, the optical film obtained from the coating composition of the present invention has less surface reflection and less reflected light. Furthermore, the coating composition of the present invention is less colored and is not colored red-purple or blue-violet even when a light source with high brightness is reflected on the display surface under specific conditions, resulting in poor display quality. An optical film with a small amount can be manufactured. In addition, an optical film having good scratch resistance can be produced.
In the optical film of the present invention, the integrated reflectance from 450 nm to 650 nm is preferably 2.0% or less, more preferably 1.5% or less, and even more preferably 1.0% or less. By setting the reflectance within the above range, there is little surface reflection, and when applied to a liquid crystal display, deterioration of visibility due to reflection of reflected light is prevented at a high level. In addition, there is no coloring, and there is no red-purple or blue-purple coloring that is of concern when a bright light source such as a fluorescent light on the back of the user heading to the display is reflected on the display surface. There is little decrease in Further, it can be produced at low cost and high productivity. In addition, polarizing plates used in various modes of liquid crystal display devices, surface protective plates combining polarizing plates used in organic EL and λ / 4 plates, flat CRT or PDP surface protective plates applied to PET films, SED surface protection It can be used for various displays such as films.

It is sectional drawing which shows typically one preferable embodiment of the antireflection film of this invention. It is sectional drawing of the coater 10 using the slot die 13 which implemented this invention. (A) shows the cross-sectional shape of the slot die 13 of the present invention, and (B) shows the cross-sectional shape of the conventional slot die 30. It is a perspective view which shows the slot die 13 of the application | coating process which implemented this invention, and its periphery. It is sectional drawing which shows the pressure reduction chamber 40 and the web W which are adjoining. (The back plate 40a is integrated with the main body of the chamber 40) It is an example of the die coater for simultaneous multilayer coating which implemented this invention.

  The present invention will be described below. In the present specification, when a numerical value represents a physical property value, a characteristic value, etc., the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”. . In the present specification, the description “(meth) acrylate” means “at least one of acrylate and methacrylate”. The same applies to “(meth) acrylic acid” and the like. Furthermore, “on the support” as used in the present invention includes both the case where the surface is the direct surface of the support and the case where the surface is a surface where a certain layer (film) is provided on the support. It is the purpose.

The optical film of the present invention (preferably an antireflection film) is a first resin component capable of forming a cured layer having a surface free energy of 30 mN / m or less on a transparent support, and the first resin component and the cured film. It has a cured layer comprising a possible second resin component and first inorganic fine particles having an average particle size of 2 nm to 100 nm, and the first resin component and / or the second resin component is ionizing radiation cured An optical film having a functional functional group, wherein the first inorganic fine particles are unevenly distributed under the cured layer, and the cured layer has an upper layer and a lower layer having different refractive indexes.
In the present specification, a layer having physical and optical functions formed on a transparent support is referred to as a functional layer. In the optical film of the present invention, the cured layer serves as a plurality of functional layers, and may further have other functional layers as required in addition to the cured layer.

[Coating composition]
The coating composition of the present invention comprises a first resin component capable of forming a cured layer having a surface free energy of 30 mN / m or less, a second resin component curable with the first resin component, and an average particle size of 2 nm. The coating composition containing the first inorganic fine particles of 100 nm or less and at least one organic solvent, wherein the first resin component and / or the second resin component has an ionizing radiation curable functional group, The coating composition is cured to form a cured layer, and the first inorganic fine particles are unevenly distributed under the cured layer to form an upper layer and a lower layer having different refractive indexes.

  The first resin component is preferably a thermosetting or ionizing radiation curable fluorine-containing compound, and the fluorine-containing compound has a silicone structure in the molecule or the coating composition has a crosslinkable group. It is more preferable that it is a compound having the same crosslinkable group as the crosslinkable group contained in the silicone compound.

In the coating composition of the present invention, the first inorganic fine particles are unevenly distributed under the cured layer, whereby the cured layer is separated into upper and lower layers having different refractive indexes. Thereby, the coating composition of this invention can serve as the composition which forms multiple layers. The cured layer will be described in detail in the description of the optical film described later.
Further details will be described below.

<First resin component>
As said 1st resin component used for this invention, it can harden | cure and can form a hardened layer, If it is resin which can form the hardened layer with the said specific surface free energy, it will use without a restriction | limiting especially. be able to.

The first resin component is a resin capable of forming a cured layer having a surface free energy of 30 mN / m or less.
The surface free energy is more preferably in the range of 18 to 25 mN / m, and particularly preferably in the range of 20 to 23 mN / m.
By setting the above range, layer separation can be formed significantly. On the other hand, if the surface free energy after curing is too high, layer separation is difficult to occur, and a decrease in reflectance or unevenness may occur. . The surface free energy is preferably set to the above preferable lower limit or more from the viewpoints of strength and applicability.

The first resin component used in the coating composition of the present invention is preferably a thermosetting or ionizing radiation curable fluorine-containing compound. Moreover, a resin component can be used individually by 1 type or in mixture of 2 or more types.
Examples of the fluorine-containing compound include the following compounds.

  The first resin component is preferably a fluorine-containing compound having a crosslinkable or polymerizable functional group, and a fluorine-containing monomer, oligomer, polymer, or fluorine-containing sol-gel material is preferably used. The fluorine-containing monomer, oligomer, polymer, or fluorine-containing sol-gel material having a crosslinkable or polymerizable functional group is preferably crosslinked by heat or ionizing radiation, and the dynamic friction coefficient of the formed low refractive index layer surface is 0. A material having a contact angle of 85 to 120 ° with respect to water is preferable. More preferred are fluorine-containing monomers, oligomers and polymers which are crosslinked by heat or ionizing radiation, and particularly preferred are fluoropolymers which are crosslinked by heat or ionizing radiation.

{First fluoropolymer for resin component}
The fluorine-containing polymer suitable for the first resin component is a fluorine-containing polymer that is cross-linked by heat or ionizing radiation, which is preferable in terms of improving productivity in the case of applying and curing a roll film while conveying the web. . From the viewpoint of productivity, a fluorine-containing polymer that is crosslinked by ionizing radiation is more preferable, and from the viewpoint of productivity and scratch resistance, a fluorine-containing polymer having a plurality of ethylenically unsaturated groups as crosslinkable groups in the molecule. Particularly preferred.
In addition, when the light scattering film of the present invention is mounted on an image display device, the lower the peel strength from a commercially available adhesive tape, the easier it is to peel off after sticking a seal or memo, so the peel strength is 500 gf (4.9 N). ) Or less, more preferably 300 gf (2.9 N) or less, and most preferably 100 gf (0.98 N) or less. Further, the higher the surface hardness measured with a microhardness meter, the harder it is to scratch. Therefore, the surface hardness is preferably 0.3 GPa or more, and more preferably 0.5 GPa or more.

  Examples of the fluorine-containing compound having a crosslinkable or polymerizable functional group include a copolymer of a fluorine-containing monomer and a monomer having a crosslinkable or polymerizable functional group. Examples of the fluorine-containing monomer include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.) (meta ) Partially or fully fluorinated alkyl ester derivatives of acrylic acid (for example, Biscoat 6FM (manufactured by Osaka Organic Chemicals) or M-2020 (manufactured by Daikin)), fully or partially fluorinated vinyl ethers, and the like.

  As an example of the monomer for imparting a crosslinkable group, a (meth) acrylate monomer having a crosslinkable functional group in the molecule in advance such as glycidyl methacrylate can be exemplified. In another embodiment, after synthesizing a fluorinated copolymer using a monomer having a functional group such as a hydroxyl group, the monomer is further modified to introduce a crosslinkable or polymerizable functional group by modifying the substituent. It is. These monomers include (meth) acrylate 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, etc.) Is mentioned. The latter embodiment is disclosed in Japanese Patent Laid-Open Nos. 10-25388 and 10-147739.

From the viewpoints of solubility, dispersibility, coatability, antifouling property, antistatic property and the like, the fluorine-containing copolymer can contain a copolymerizable component as appropriate. In particular, for imparting antifouling properties and slipperiness, it is preferable to introduce silicone, and it can be introduced into both the main chain and the side chain.
The polysiloxane partial structure introduction method to the main chain is, for example, an azo group-containing polysiloxane amide described in JP-A-6-93100 (VPS-0501, 1001 (trade name; Wako Pure Chemical Industries, Ltd. And a method using a polymer-type initiator such as a company)).
Further, the method of introducing into the side chain is, for example, as described in J. Appl. Polym. Sci. 2000, 78, 1955, JP-A-56-28219, etc. For example, a silaplane series (manufactured by Chisso Corporation) can be synthesized by a method of polymer reaction or a method of polymerizing a polysiloxane-containing silicon macromer, and both methods can be preferably used.

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

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

  Specific examples of these fluoropolymers are described in JP2003-222702A, JP2003-183322A, and the like.

{Fluorine-containing compounds having crosslinkable or polymerizable functional groups}
Examples of the fluorine-containing compound having a crosslinkable or polymerizable functional group include a copolymer of a fluorine-containing monomer and a monomer having a crosslinkable or polymerizable functional group as described above. Examples of the fluorine-containing monomer include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.) (meta ) Partially or fully fluorinated alkyl ester derivatives of acrylic acid (for example, Biscoat 6FM (manufactured by Osaka Organic Chemicals) or M-2020 (manufactured by Daikin)), fully or partially fluorinated vinyl ethers, and the like.

Further, a fluorine-containing compound having crosslinkability can also be used. As the fluorine-containing compound, a compound having a fluoroalkyl group is preferable. The fluoroalkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and a straight chain (for example, —CF ₂ CF ₃ , —CH ₂ (CF ₂ ) ₄ H, —CH ₂ (CF ₂ ) 8CF ₃ , —CH ₂ CH ₂ (CF ₂ ) ₄ H, etc.), even branched structures (eg, CH (CF ₃ ) ₂ , CH ₂ CF (CF ₃ ) ₂ , CH (CH ₃ ) CF ₂ CF ₃ , CH (CH ₃ ) (CF ₂ ) ₅ CF ₂ H, etc.), but alicyclic structures (preferably 5-membered or 6-membered rings such as perfluorocyclohexyl group, perfluorocyclopentyl group) Or an alkyl group substituted with these, or may have an ether bond (for example, CH ₂ OCH ₂ CF ₂ CF ₃ , CH ₂ CH ₂ OCH ₂ C ₄ F ₈ H, CH ₂ CH ₂ OCH ₂ CH ₂ C ₈ F ₁₇ , CH ₂ CH ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ H, etc.). A plurality of the fluoroalkyl groups may be contained in the same molecule.

  Examples of the crosslinkable group include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, polyoxyalkylene group, carboxyl group and amino group. The fluorine-based compound may be a copolymer or an oligomer with a compound not containing a fluorine atom, and the molecular weight is not particularly limited. Although there is no restriction | limiting in particular in fluorine atom content of a fluorine-containing compound, It is preferable that it is 20 mass% or more, It is especially preferable that it is 30-70 mass%, It is most preferable that it is 40-70 mass%. Preferred examples of such a fluorine-containing compound having a crosslinkable group include Daikin Chemical Industries, Ltd., R-2020, M-2020, R-3833, M-3833 (trade names), Dai Nippon Ink Co., Ltd. ) Manufactured by Megafac F-171, F-172, F-179A, and defender MCF-300 (trade name), but are not limited thereto.

{Hydrolysis condensate of fluorine-containing organosilane material}
As the first resin component, a composition mainly composed of a hydrolyzed condensate of a fluorine-containing organosilane compound can also be preferably used because it has a low refractive index and a high hardness on the surface of the coating film. A condensate of a tetraalkoxysilane with a hydrolyzable silanol-containing compound at one or both ends with respect to the fluorinated alkyl group is preferred. The specific composition is described in Unexamined-Japanese-Patent No. 2002-265866, 317152.

The fluorine-containing compound suitable as the first resin component preferably has a silicone structure in the molecule as described above. However, the coating composition may contain a silicone compound containing the same crosslinkable group as the fluorine-containing compound. Good.
Examples of the compound having a silicone structure in the molecule include the following compounds.

  Examples of the silicone compound containing a crosslinkable group include those having a substituent at the terminal and / or side chain of a compound chain containing a plurality of dimethylsilyloxy units as repeating units. The compound chain containing dimethylsilyloxy as a repeating unit may contain a structural unit other than dimethylsilyloxy. The substituents may be the same or different, and a plurality of substituents are preferable. Examples of preferred substituents include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, fluoroalkyl group, polyoxyalkylene group, carboxyl group, amino group and the like. It is done. Although there is no restriction | limiting in particular in molecular weight, It is preferable that it is 100,000 or less, It is more preferable that it is 50,000 or less, It is especially preferable that it is 3000-30000, It is most preferable that it is 10,000-20000. Although there is no restriction | limiting in particular in silicone atom content of a silicone compound, it is preferable that it is 18.0 mass% or more, it is especially preferable that it is 25.0-37.8 mass%, and 30.0-37.0 mass. % Is most preferred. Examples of preferred silicone compounds are X-22-174DX, X-22-2426, X-22-164B, X22-164C, X-22-170DX, X-22-176D, X-, manufactured by Shin-Etsu Chemical Co., Ltd. 22-1821 (named above), Chisso Corporation, FM-0725, FM-7725, FM-4421, FM-5521, FM6621, FM-1221, Gelest DMS-U22, RMS-033, RMS-083 , UMS-182, DMS-H21, DMS-H31, HMS-301, FMS121, FMS123, FMS131, FMS141, FMS221 (above trade names) and the like, but are not limited thereto.

  The silicone compound is preferably added in an amount of 0.01 to 20% by mass, more preferably 0.05 to 10% by mass of the first resin component. Yes, particularly preferably 0.1 to 7% by mass.

<Second resin component>
The coating composition of the present invention and / or the composition for forming each layer contains a first resin component and a curable second resin component. As a preferred example of the second resin component, a monomer or oligomer having a reactive group that crosslinks by heat or ionizing radiation is preferable, and a resin component having a polyfunctional monomer or polyfunctional oligomer having two or more functional groups is more preferable, A resin component having a polyfunctional monomer or polyfunctional oligomer having three or more functional groups is more preferable. These polyfunctional monomers and oligomers are also preferably contained in the composition for forming a layer that the optical film of the present invention and the antireflection film may have other than the layer formed using the coating composition of the present invention. The

The second resin component preferably has a larger surface free energy than the first resin component. A resin capable of forming a cured layer having a surface free energy of 30 mN / m or more is preferable, a range of 35 to 80 mN / m is more preferable, and a range of 40 to 60 mN / m is particularly preferable. The difference in surface free energy between the first resin component and the second resin component is preferably 5 mN / m or more, and more preferably 10 mN / m or more and 40 mN / m or less.
By setting it as the above range, layer separation is more easily formed. If the surface free energy after curing is too high or too low, a decrease in reflectance or unevenness may occur. The surface free energy is preferably set to the above preferable lower limit or more from the viewpoints of strength and applicability.

The functional group of the ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer is preferably a light, electron beam, or radiation polymerizable group, and among them, a photopolymerizable functional group is preferable.
Specific examples of the photopolymerizable functional group include unsaturated polymerizable functional groups such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Of these, a (meth) acryloyl group is preferable. .

As a specific example of a photopolymerizable polyfunctional monomer having a photopolymerizable functional group,
(Meth) acrylic acid diesters of alkylene glycol such as neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate;
(Meth) acrylic acid diesters of polyoxyalkylene glycols such as triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate;
(Meth) acrylic acid diesters of polyhydric alcohols such as pentaerythritol di (meth) acrylate;
(Meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts such as 2,2-bis {4- (acryloxy · diethoxy) phenyl} propane and 2-bis {4- (acryloxy · polypropoxy) phenyl} propane And the like.

  Furthermore, epoxy (meth) acrylates, urethane (meth) acrylates, and polyester (meth) acrylates are also preferably used as the photopolymerizable polyfunctional monomer.

  Among these, esters of polyhydric alcohol and (meth) acrylic acid are preferable. More preferably, a polyfunctional monomer having 3 or more (meth) acryloyl groups in one molecule is preferable. Specifically, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, 1,2,4-cyclohexanetetra (meth) acrylate, pentaglycerol triacrylate, pentaerythritol tetra (meth) acrylate, penta Erythritol tri (meth) acrylate, (di) pentaerythritol triacrylate, (di) pentaerythritol pentaacrylate, (di) pentaerythritol tetra (meth) acrylate, (di) pentaerythritol hexa (meth) acrylate, tripentaerythritol triacrylate , Tripentaerythritol hexatriacrylate and the like. In the present specification, “(meth) acrylate”, “(meth) acrylic acid”, and “(meth) acryloyl” represent “acrylate or methacrylate”, “acrylic acid or methacrylic acid”, and “acryloyl or methacryloyl”, respectively. .

As the monomer binder, monomers having different refractive indexes can be used to control the refractive index of each layer. Examples of particularly high refractive index monomers include bis (4-methacryloylthiophenyl) sulfide, vinyl naphthalene, vinyl phenyl sulfide, 4-methacryloxyphenyl-4′-methoxyphenyl thioether, and the like.
Further, for example, dendrimers described in JP-A-2005-76005 and JP-A-2005-36105, and norbornene ring-containing monomers as described in JP-A-2005-60425 can also be used.

Two or more polyfunctional monomers may be used in combination.
When using the said resin component, it is preferable to use the photoinitiator used for the polymerization reaction of a photopolymerizable polyfunctional monomer. As the photopolymerization initiator, a photoradical polymerization initiator and a photocationic polymerization initiator are preferable, and a photoradical polymerization initiator is particularly preferable.

(Polymerization initiator)
The polymerization of the monomer having an ethylenically unsaturated group can be performed by irradiation with ionizing radiation or heating in the presence of a photo radical initiator or a thermal radical initiator. Accordingly, a coating liquid containing a monomer having an ethylenically unsaturated group, a photo radical initiator or a thermal radical initiator, metal oxide particles, and, if necessary, matte particles is prepared, and the coating liquid is placed on the transparent support. After coating, it can be cured by a polymerization reaction with ionizing radiation or heat to form a hard coat layer of an antireflection film.

(Photo radical polymerization initiator)
As radical photopolymerization initiators, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides (described in JP 2001-139663 A), Examples include 2,3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfoniums, onium salts, borate salts, and active halogen compounds.

  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 is included.

  Examples of benzoins include benzoin benzene sulfonate, benzoin toluene sulfonate, 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.

  “Latest UV Curing Technology” {Publisher: Kazuhiro Takasato, Publisher; Technical Information Association, 1991}, p. 159, and “UV Curing System” (written by Kiyotsugu Kato, published by General Technology Center in 1989), pages 65 to 148, are described in various examples and are useful for the present invention.

  As a commercially available photocleavable photoradical polymerization initiator, a trade name “Irgacure (651, 184, 907)” manufactured by Ciba Geigy Japan, Inc. can be mentioned as a preferred example.

  It is preferable to use a photoinitiator in the range of 0.1-15 mass parts with respect to 100 mass parts of polyfunctional monomers, More preferably, it is the range of 1-10 mass parts.

(Photosensitizer)
In addition to the photopolymerization initiator, a photosensitizer may be used. Specific examples of the photosensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, Michler's ketone and thioxanthone.

  Moreover, as said 2nd resin component, the following organosilane compound other than the above-mentioned compound can also be used preferably.

<Organosilane compound for low refractive index layer>
The second resin composition includes an organosilane compound, a hydrolyzate of the organosilane, and a partial condensate of the hydrolyzate of the organosilane (hereinafter, the obtained reaction solution is also referred to as “sol component”). It is preferable to contain at least one selected from the viewpoints of scratch resistance and surface free energy.
These components function as a binder by applying the curable composition and then condensing in a drying and heating process to form a cured product. In the present invention, since the fluorine-containing compound preferably has the fluorine-containing polymer, a binder having a three-dimensional structure is formed by irradiation with actinic rays.
The organosilane compound is preferably represented by the following general formula (1).
Formula _{^{(1) :( R 10) m}} -Si (X) 4-m

In the general formula (1), R ¹⁰ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, hexyl, decyl, hexadecyl and the like. The alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 6 carbon atoms.
Examples of the aryl group include phenyl and naphthyl, and a phenyl group is preferable.
X represents a hydroxyl group or a hydrolyzable group, for example, an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms, such as a methoxy group or an ethoxy group), a halogen atom (for example, Cl, Br, I or the like). ) And R ² COO (R ² is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Examples include CH ₃ COO, C ₂ H ₅ COO, etc.), preferably An alkoxy group, particularly preferably a methoxy group or an ethoxy group. m represents an integer of 1 to 3, preferably 1 or 2, and particularly preferably 1.

When R ¹⁰ or X there are a plurality, a plurality of R ¹⁰ or X groups may be different, even the same, respectively.
The substituent contained in R ¹⁰ is not particularly limited, but a halogen atom (fluorine, chlorine, bromine, etc.), hydroxyl group, mercapto group, carboxyl group, epoxy group, alkyl group (methyl, ethyl, i-propyl, propyl, t-butyl etc.), aryl groups (phenyl, naphthyl etc.), aromatic heterocyclic groups (furyl, pyrazolyl, pyridyl etc.), alkoxy groups (methoxy, ethoxy, i-propoxy, hexyloxy etc.), aryloxy (phenoxy etc.) ), Alkylthio groups (methylthio, ethylthio, etc.), arylthio groups (phenylthio, etc.), alkenyl groups (vinyl, 1-propenyl, etc.), acyloxy groups (acetoxy, acryloyloxy, methacryloyloxy, etc.), alkoxycarbonyl groups (methoxycarbonyl, ethoxy) Carbonyl, etc.), aryloxy Carbonyl groups (such as phenoxycarbonyl), carbamoyl groups (such as carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N-methyl-N-octylcarbamoyl), acylamino groups (acetylamino, benzoylamino, acrylicamino, methacrylamino) Etc.), and these substituents may be further substituted.

When there are a plurality of R ^{10 s} , at least one is preferably a substituted alkyl group or a substituted aryl group. Among the organosilane compounds represented by the general formula (1), an organosilane compound having a vinyl polymerizable substituent represented by the following general formula (2) is preferable.

General formula (2)

In the general formula (2), R ¹ represents a hydrogen atom, a methyl group, a methoxy group, an alkoxycarbonyl group, a cyano group, a fluorine atom, or a chlorine atom. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group. A hydrogen atom, a methyl group, a methoxy group, a methoxycarbonyl group, a cyano group, a fluorine atom, and a chlorine atom are preferable, a hydrogen atom, a methyl group, a methoxycarbonyl group, a fluorine atom, and a chlorine atom are more preferable, and a hydrogen atom and a methyl group Is particularly preferred.
Y represents a single bond or * -COO-**, * -CONH-** or * -O-**, preferably a single bond, * -COO-** or * -CONH-**, * -COO-** is more preferable, and * -COO-** is particularly preferable. * Represents a position bonded to ═C (R ¹ ) —, and ** represents a position bonded to L.

  L represents a divalent linking chain. Specifically, a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, a substituted or unsubstituted alkylene group having a linking group (eg, ether, ester, amide, etc.) inside, and a linking group inside. A substituted or unsubstituted arylene group, a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, and an alkylene group having a linking group therein are preferred, an unsubstituted alkylene group and an unsubstituted arylene group Further, an alkylene group having an ether or ester linking group inside is more preferable, an unsubstituted alkylene group, and an alkylene group having an ether or ester linking group inside is particularly preferable. Examples of the substituent include a halogen, a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, and an aryl group, and these substituents may be further substituted.

n represents 0 or 1. When there are a plurality of Xs, the plurality of Xs may be the same or different. n is preferably 0.
R ¹⁰ has the same meaning as in formula (1), preferably a substituted or unsubstituted alkyl group or an unsubstituted aryl group, and more preferably an unsubstituted alkyl group or an unsubstituted aryl group.
X has the same meaning as in formula (1), preferably a halogen atom, a hydroxyl group, or an unsubstituted alkoxy group, more preferably a chlorine atom, a hydroxyl group, or an unsubstituted alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, or a carbon number of 1 -3 alkoxy groups are more preferred, and methoxy groups are particularly preferred.

  Two or more kinds of the compounds represented by the general formulas (1) and (2) may be used in combination. Specific examples of the compounds represented by general formula (1) and general formula (2) are shown below, but the present invention is not limited thereto.

  Of the compounds represented by M-1 to 75, M-1, M-2 and M-49 are preferable.

  The hydrolyzate and / or partial condensate of the organosilane compound is generally produced by treating the organosilane compound in the presence of a catalyst. Catalysts include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid; organic acids such as oxalic acid, acetic acid, formic acid, methanesulfonic acid and toluenesulfonic acid; inorganic bases such as sodium hydroxide, potassium hydroxide and ammonia; triethylamine, Examples thereof include organic bases such as pyridine; metal alkoxides such as triisopropoxyaluminum and tetrabutoxyzirconium; metal chelate compounds having a metal such as Zr, Ti or Al as a central metal. In the present invention, it is preferable to use a metal chelate compound, an acid catalyst of inorganic acids and organic acids. Inorganic acids are preferably hydrochloric acid and sulfuric acid, and organic acids are preferably those having an acid dissociation constant (pKa value (25 ° C.)) of 4.5 or less in water, and further, acid dissociation constants in hydrochloric acid, sulfuric acid and water. Is preferably an organic acid having an acid dissociation constant of 2.5 or less in hydrochloric acid, sulfuric acid or water, more preferably an organic acid having an acid dissociation constant of 2.5 or less in water. Specifically, methanesulfonic acid, oxalic acid, phthalic acid, and malonic acid are more preferable, and oxalic acid is particularly preferable.

As the metal chelate compound, (wherein, R ³ represents an alkyl group having 1 to 10 carbon atoms) Formula R ³ OH alcohol and R ⁴ COCH ₂ COR ⁵ (formula represented by, R ⁴ is the number of carbon atoms 1 to 10 alkyl groups, R ⁵ is an alkyl group having 1 to 10 carbon atoms or a compound represented by an alkoxy group having 1 to 10 carbon atoms), and is selected from Zr, Ti, and Al. Any metal having a central metal as the metal can be used without any particular limitation. Within this category, two or more metal chelate compounds may be used in combination. The metal chelate compound used in the present invention has the general formula Zr (OR ³ ) _p1 (R ⁴ COCHCOR ⁵ ) _p2 , Ti (OR ³ ) _q1 (R ⁴ COCHCOR ⁵ ) _q2 , and Al (OR ³ ) _r1 (R ⁴ Those selected from the group of compounds represented by COCHCOR ⁵ ) _r2 are preferred and serve to promote the condensation reaction of the hydrolyzate and / or partial condensate of the organosilane compound.

R ³ and R ⁴ in the metal chelate compound may be the same or different, and an alkyl group having 1 to 10 carbon atoms, specifically, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, sec -Butyl group, t-butyl group, n-pentyl group, phenyl group and the like. R ⁵ represents an alkyl group having 1 to 10 carbon atoms as described above, or an alkoxy group having 1 to 10 carbon atoms such as a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, and n-butoxy. Group, sec-butoxy group, t-butoxy group and the like. Moreover, p1, p2, q1, q2, r1, and r2 in the metal chelate compound represent integers determined so as to be p1 + p2 = 4, q1 + q2 = 4, and r1 + r2 = 3, respectively.

  Specific examples of these metal chelate compounds include tri-n-butoxyethyl acetoacetate zirconium, di-n-butoxybis (ethylacetoacetate) zirconium, n-butoxytris (ethylacetoacetate) zirconium, tetrakis (n-propylacetate). Zirconium chelate compounds such as acetate) zirconium, tetrakis (acetylacetoacetate) zirconium, tetrakis (ethylacetoacetate) zirconium; diisopropoxy bis (ethylacetoacetate) titanium, diisopropoxy bis (acetylacetate) titanium, diiso Titanium chelate compounds such as propoxy bis (acetylacetone) titanium; diisopropoxyethyl acetoacetate aluminum, diisopropyl Poxyacetylacetonate aluminum, isopropoxybis (ethylacetoacetate) aluminum, isopropoxybis (acetylacetonate) aluminum, tris (ethylacetoacetate) aluminum, tris (acetylacetonato) aluminum, monoacetylacetonate bis (ethyl) An aluminum chelate compound such as acetoacetate) aluminum.

  Among the specific examples of the metal chelate compounds, tri-n-butoxyethyl acetoacetate zirconium, diisopropoxybis (acetylacetonato) titanium, diisopropoxyethyl acetoacetate aluminum, and tris (ethyl acetoacetate) aluminum are preferable. is there. These metal chelate compounds can be used individually by 1 type or in mixture of 2 or more types. Moreover, the partial hydrolyzate of these metal chelate compounds can be used.

  In the present invention, it is preferable that a β-diketone compound and / or a β-ketoester compound is further added to the curable composition. This will be further described below.

The β-diketone compound and / or β-ketoester compound represented by the general formula R ⁴ COCH ₂ COR ⁵ is used in the present invention, and is used as a stability improver for the curable composition used in the present invention. It works. Here, R ⁴ represents an alkyl group having 1 to 10 carbon atoms, and R ⁵ represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms. That is, by coordinating with the metal atom in the metal chelate compound (zirconium, titanium and / or aluminum compound), the condensation reaction of the hydrolyzate and / or partial condensate of the organosilane compound by these metal chelate compounds is performed. It is considered that the promoting action is suppressed and the storage stability of the resulting composition is improved. R ⁴ and R ⁵ constituting the β- diketone compound and / or β- ketoester compound are the same as R ⁴ and R ⁵ constituting the metal chelate compound.

  Specific examples of the β-diketone compound and / or β-ketoester compound include acetylacetone, methyl acetoacetate, ethyl acetoacetate, acetoacetate-n-propyl, acetoacetate-i-propyl, acetoacetate-n-butyl, acetoacetate. Acetic acid-sec-butyl, acetoacetic acid-t-butyl, 2,4-hexane-dione, 2,4-heptane-dione, 3,5-heptane-dione, 2,4-octane-dione, 2,4-nonane -Dione, 5-methyl-hexane-dione and the like can be mentioned. Of these, ethyl acetoacetate and acetylacetone are preferred, and acetylacetone is particularly preferred. These β-diketone compounds and / or β-ketoester compounds may be used alone or in combination of two or more. In the present invention, the β-diketone compound and / or β-ketoester compound is preferably used in an amount of 2 mol or more, more preferably 3 to 20 mol, per 1 mol of the metal chelate compound. Within the above range, good storage stability can be obtained.

  5-100 mass% is preferable, as for the usage-amount of the 2nd resin component with respect to a 1st resin component, 5-50 mass% is more preferable, 8-40 mass% is further more preferable, and 10-30 mass% is especially preferable. . If the amount used is small, it is difficult to obtain the effect of the present invention, and if the amount used is too large, the refractive index increases or the shape / surface shape of the film deteriorates. Moreover, the 1st resin component and the 2nd resin component can each be used individually by 1 type or in mixture of 2 or more types.

<First inorganic fine particles>
The first inorganic fine particle used in the present invention is an inorganic fine particle having an average particle diameter of 2 nm to 100 nm, preferably an inorganic fine particle having an average particle diameter of 5 nm to 80 nm, more preferably 10 nm to 60 nm. The following inorganic fine particles.
When the average particle size is less than 2 nm, the particles easily aggregate and are difficult to disperse. When the average particle size exceeds 100 nm, the haze increases.
Examples of the first inorganic fine particles include the inorganic fine particles described below, and can be used alone or in combination of two or more.

  As the first inorganic fine particles, it is preferable to use inorganic fine particles mainly composed of an oxide of at least one metal selected from at least titanium, zirconium, aluminum, indium, zinc, tin, and antimony. When these inorganic fine particles are unevenly distributed in the lower part of the cured layer, the lower part preferably has a high refractive index in order to increase the refractive index of the lower part and sufficiently reduce the reflectance of the optical film of the present invention. Is preferably 1.60 to 3.00, more preferably 1.80 to 2.90, and particularly preferably 1.90 to 2.80.

As the first inorganic fine particles, it is particularly desirable to use at least one metal oxide selected from metal oxides mainly composed of oxides of at least one metal selected from titanium and zirconium. . Of these, zirconium having no photocatalytic action is preferable from the viewpoint of light resistance, but it is also preferable to use titanium in which the photocatalytic action is suppressed.
Also, from the viewpoint of antistatic, it is desirable to use conductive inorganic fine particles, and among the inorganic fine particles mainly composed of an oxide of at least one metal selected from indium, zinc, tin, and antimony. It is desirable to use at least one selected metal oxide.
The first inorganic fine particles are suitably used as inorganic fine particles for adjusting the refractive index in the other layers used in the optical film of the present invention, for example, in the hard coat layer and the medium refractive index layer.

{Surface treatment of first inorganic fine particles}
The first inorganic fine particles are preferably surface-treated. Specific means of surface treatment include dispersion stabilization and improved affinity / binding properties with resin components such as binders in coating compositions, compositions for forming each layer, or dispersions added to these compositions. If it can do, it will not be specifically limited. Regarding the surface treatment, in addition to the detailed description in the section “Dispersant and surface treatment agent for inorganic fine particles”, the organosilane compound described as the second resin component, the hydrolyzate of the organosilane, the organosilane A partial condensate of a hydrolyzate is preferably used.

[Dispersant of inorganic fine particles, surface treatment agent]
Inorganic particles used in the present invention are dispersed in a dispersion liquid or a coating liquid, such as plasma discharge treatment or corona discharge treatment in order to stabilize dispersion or to increase affinity and binding properties with a binder component. It is preferable that chemical surface treatment with a physical surface treatment or a surfactant or a coupling agent is performed.

The surface treatment can be carried out using a surface treatment agent of an inorganic compound or an organic compound. Examples of inorganic compounds used for the surface treatment include inorganic compounds containing cobalt (CoO ₂ , Co ₂ O ₃ , Co ₃ O _4, etc.), inorganic compounds containing aluminum (Al ₂ O ₃ , Al (OH) _{3, etc.} Etc.), inorganic compounds containing zirconium (ZrO ₂ , Zr (OH) ₄ etc.), inorganic compounds containing silicon (SiO ₂ etc.), inorganic compounds containing iron (Fe ₂ O ₃ etc.), etc. .
Inorganic compounds containing cobalt, inorganic compounds containing aluminum, and inorganic compounds containing zirconium are particularly preferred, and inorganic compounds containing cobalt, Al (OH) ₃ , and Zr (OH) ₄ are most preferred.
Examples of the organic compound used for the surface treatment include polyols, alkanolamines, stearic acid, silane coupling agents, and titanate coupling agents. Silane coupling agents are most preferred. In particular, the surface treatment is preferably performed with at least one of a silane coupling agent (organosilane compound), a partial hydrolyzate thereof, and a condensate thereof.

Examples of titanate coupling agents include metal alkoxides such as tetramethoxy titanium, tetraethoxy titanium, and throat tetraisopropoxy titanium, and preneact (KR-TTS, KR-46B, KR-55, KR-41B, etc .; Ajinomoto Co., Inc. ))).
Examples of the organic compound used for the surface treatment include polyols, alkanolamines, and other organic compounds having an anionic group, and particularly preferable are organic compounds having a carboxyl group, a sulfonic acid group, or a phosphoric acid group. is there. Stearic acid, lauric acid, oleic acid, linoleic acid, linolenic acid and the like can be preferably used.
The organic compound used for the surface treatment preferably further has a crosslinked or polymerizable functional group. Crosslinkable or polymerizable functional groups include ethylenically unsaturated groups (for example, (meth) acrylic groups, allyl groups, styryl groups, vinyloxy groups, etc.) that can undergo addition reactions and polymerization reactions with radical species, cationic polymerizable groups (Epoxy groups, oxatanyl groups, vinyloxy groups, etc.), polycondensation reactive groups (hydrolyzable silyl groups, etc., N-methylol groups) and the like can be mentioned, and groups having an ethylenically unsaturated group are preferred.

  Two or more kinds of these surface treatments can be used in combination, and it is particularly preferable to use an inorganic compound containing aluminum and an inorganic compound containing zirconium.

A coupling agent is also preferably used. As the coupling agent, an alkoxy metal compound (eg, titanium coupling agent, silane coupling agent) is preferably used. Of these, silane coupling treatment is particularly effective. The silane coupling agent may be used as a partial hydrolyzate or condensate.
The above-mentioned coupling agent is used as a surface treatment agent for inorganic fine particles in advance for surface treatment prior to the preparation of the coating solution for the layer. Is preferred.
The inorganic fine particles are preferably dispersed in the medium in advance before the surface treatment in order to reduce the load of the surface treatment.
Specific examples of the surface treatment agent and the surface treatment catalyst that can be preferably used in the present invention include organosilane compounds and catalysts described in WO 2004/017105.

The following various dispersants can also be preferably used for dispersing the particles used in the present invention.
The dispersant preferably further contains a cross-linkable or polymerizable functional group. Crosslinkable or polymerizable functional groups include ethylenically unsaturated groups (for example, (meth) acryloyl groups, allyl groups, styryl groups, vinyloxy groups, etc.) that can undergo addition reactions and polymerization reactions with radical species, and cationic polymerizable groups (epoxies). Groups, oxatanyl groups, vinyloxy groups, etc.), polycondensation reactive groups (hydrolyzable silyl groups, etc., N-methylol groups) and the like, and functional groups having an ethylenically unsaturated group are preferred.

It is preferable to use a dispersant having an anionic group for the dispersion of inorganic particles, particularly for the dispersion of inorganic particles containing TiO ₂ as a main component, more preferably having an anionic group and a crosslinkable or polymerizable functional group, It is particularly preferable that the dispersant has the cross-linked or polymerizable functional group in the side chain.

  As the anionic group, a group having an acidic proton such as a carboxyl group, a sulfonic acid group (sulfo), a phosphoric acid group (phosphono), a sulfonamide group, or a salt thereof is effective, and in particular, a carboxyl group, a sulfonic acid group, A phosphoric acid group or a salt thereof is preferable, and a carboxyl group or a phosphoric acid group is particularly preferable. The number of anionic groups contained in the dispersing agent per molecule may be plural, but is preferably 2 or more on average, more preferably 5 or more, Particularly preferred is 10 or more. Moreover, the anionic group contained in a dispersing agent may contain multiple types in 1 molecule.

In the dispersant having an anionic group in the side chain, the composition of the anionic group-containing repeating unit is a ^10-4 range ～100Mol% of the total repeating units, preferably 1 to 50 mol%, particularly preferably 5 ˜20 mol%.

  The dispersant preferably further contains a cross-linkable or polymerizable functional group. Crosslinkable or polymerizable functional groups include ethylenically unsaturated groups (for example, (meth) acryloyl groups, allyl groups, styryl groups, vinyloxy groups, etc.) that can undergo addition reactions and polymerization reactions with radical species, and cationic polymerizable groups (epoxies). Groups, oxatanyl groups, vinyloxy groups, etc.), polycondensation reactive groups (hydrolyzable silyl groups, etc., N-methylol groups) and the like, and functional groups having an ethylenically unsaturated group are preferred.

  The average number of cross-linkable or polymerizable functional groups contained in the dispersant per molecule is preferably 2 or more, more preferably 5 or more, and particularly preferably 10 or more. Moreover, the crosslinking or polymerizable functional group contained in the dispersant may contain a plurality of types in one molecule.

In the preferred dispersant used in the present invention, examples of the repeating unit having an ethylenically unsaturated group in the side chain include poly-1,2-butadiene and poly-1,2-isoprene structures, or (meth) acrylic acid. An ester or amide repeating unit to which a specific residue (the R group of —COOR or —CONHR) is bonded can be used. Examples of the specific residue (R _{group), - (CH 2) n} -CR 21 = CR 22 R 23, - (CH 2 O) n-CH 2 CR 21 = CR 22 R 23, - (CH _{2 CH 2 O) n-CH} 2 CR 21 = CR 22 R 23, - (CH 2) n-NH-CO-O-CH 2 CR 21 = CR 22 R 23, - (CH 2) n-O-CO —CR ²¹ ═CR ²² R ²³ and — (CH ₂ CH ₂ O) ₂ —X (R ^{21 to} R ²³ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, or an alkoxy group. R ²¹ and R ²² or R ²³ may be bonded to each other to form a ring, n is an integer of 1 to 10, and X is a dicyclopentadienyl residue. There are). Specific examples of R of the ester residue include —CH ₂ CH═CH ₂ (corresponding to an allyl (meth) acrylate polymer described in JP-A No. 64-17047), —CH ₂ CH ₂ O—CH ₂ CH _{= CH 2, -CH 2 CH 2} OCOCH = CH 2, -CH 2 CH 2 OCOC (CH 3) = CH 2, -CH 2 C (CH 3) = CH 2, -CH 2 CH = CH-C 6 H ₅ , —CH ₂ CH ₂ OCOCH═CH—C ₆ H ₅ , —CH ₂ CH ₂ —NHCOO—CH ₂ CH═CH ₂ and —CH ₂ CH ₂ O—X (X is a dicyclopentadienyl residue) Is included. Specific examples of R of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (Y is a 1-cyclohexenyl residue) and —CH ₂ CH ₂ —OCO—CH═CH ₂ , _{-CH 2 CH 2 -OCO-C (} CH 3) = CH 2 are included.

  In the dispersant having an ethylenically unsaturated group, a free radical (a polymerization initiation radical or a growth radical in the polymerization process of the polymerizable compound) is added to the unsaturated bond group, and the polymerizable compound directly or between the molecules. Addition polymerization is carried out through the polymerization chain, and a crosslink is formed between the molecules to cure. Alternatively, atoms in the molecule (for example, hydrogen atoms on carbon atoms adjacent to the unsaturated bond group) are extracted by free radicals to form polymer radicals that are bonded together to form a bridge between the molecules. Harden.

  The weight average molecular weight (Mw) of the dispersant having an anionic group and a crosslinkable or polymerizable functional group and having the crosslinkable or polymerizable functional group in the side chain is not particularly limited, but is preferably 1000 or more. . The more preferable weight average molecular weight (Mw) of the dispersant is 2000 to 1000000, more preferably 5000 to 200000, and particularly preferably 10000 to 100000.

  The cross-linkable or polymerizable functional group-containing unit may constitute all repeating units other than the anionic group-containing repeating unit, preferably 5 to 50 mol% of the total cross-linking or repeating unit, particularly Preferably it is 5-30 mol%.

  The dispersant may be a copolymer with an appropriate monomer other than a monomer having a crosslinking or polymerizable functional group or an anionic group. Although it does not specifically limit regarding a copolymerization component, It selects from various viewpoints, such as dispersion stability, compatibility with another monomer component, and the intensity | strength of a formed film. Preferable examples include methyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, styrene and the like.

  The form of the dispersant is not particularly limited, but is preferably a block copolymer or a random copolymer, and particularly preferably a random copolymer from the viewpoint of cost and ease of synthesis.

  The amount of the dispersant used relative to the inorganic particles is preferably in the range of 1 to 50% by mass, more preferably in the range of 5 to 30% by mass, and most preferably 5 to 20% by mass. Two or more dispersants may be used in combination.

  Specific examples of the dispersant preferably used in the present invention are shown below, but the dispersant for the present invention is not limited thereto. Unless otherwise specified, it represents a random copolymer.

[Dispersion of inorganic fine particles]
The inorganic fine particles can be dispersed 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 inorganic fine particles are preferably made as fine as possible in the dispersion medium, and the preferred weight average diameter is in accordance with the aforementioned particle diameter.

{Surface free energy of the first inorganic fine particles}
The surface free energy of the first inorganic fine particles is higher than the surface free energy of the first resin component, and the difference between the two is 10 mN / m or more in order to advantageously form a layer separation structure. And more preferably 15 mN / m or more and 60 mN / m or less, and particularly preferably 20 mN / m or more and 50 mN / m or less. By setting the above range, layer separation can be formed significantly. On the other hand, if the surface free energy is too high or too low, a decrease in reflectance, unevenness, or the like may occur. The surface free energy is preferably within the above-mentioned preferable range from the viewpoints of strength and applicability.

The surface free energy of the inorganic fine particles is obtained by statically settling or centrifuging the coating composition, repeating solvent washing, removing components other than inorganic fine particles, casting on the washed glass plate, drying the solvent, and forming a thin film. It can calculate using the contact angle of water and methylene iodide of the inorganic fine particles. The surface free energy of other components such as a resin component can be calculated in the same manner.
The mixing ratio of the first inorganic fine particles in the coating composition can be adjusted according to the content of the inorganic fine particles in each layer when the coating composition is used as the composition for forming each layer.

<Second inorganic fine particles>
Further, in the coating composition of the present invention, as the second inorganic fine particles in addition to the above-described components, a refractive index of 1.46 or less, more desirably a refractive index of 1.17 to 1.46, particularly preferably 1. It is preferable to contain inorganic fine particles of 17 to 1.40, more preferably 1.17 to 1.35, and most preferably 1.17 to 1.32. The second inorganic fine particles are unevenly distributed in the upper part of the hardened layer and contribute to the improvement of scratch resistance and the reduction of the refractive index.
Examples of the second inorganic fine particles include the inorganic fine particles described below, and these can be used alone or in combination of two or more.
Specific examples of such second inorganic fine particles include fine particles of magnesium fluoride and silicon oxide (silica). In particular, silica fine particles are preferable in terms of refractive index, dispersion stability, and cost.
The average particle diameter of the inorganic fine particles is preferably 10 nm to 100 nm, more preferably 15 nm to 80 nm, and still more preferably 30 nm to 60 nm.
If the particle size of the inorganic fine particles is too small, the effect of improving the scratch resistance is reduced. It is preferable to be within the above-mentioned range. The inorganic fine particles may be either crystalline or amorphous, and may be monodispersed particles or aggregated particles as long as a predetermined particle size is satisfied. The shape is most preferably a spherical diameter, but there is no problem even if the shape is indefinite.
Here, the average particle diameter of the inorganic fine particles is measured by a Coulter counter.

More preferably, the inorganic fine particles have a hollow structure. In the case of inorganic fine particles having a hollow structure, the refractive index does not represent the refractive index of the outer shell only, but represents the average value of the entire particle. At this time, the radius of the cavity inside the particle a, when the radius of the outer shell of the particle b, the porosity x represented by the following formula (II) (Formula ^{II): x = (4πa 3} /3) / (4πb ^3/3) a × 100, preferably from 10% to 60%, further preferably 20 to 60%, most preferably 30 to 60%.
If the refractive index of the hollow inorganic fine particles is made lower and the porosity is increased, the thickness of the outer shell becomes thinner and the strength of the particles becomes weaker. From the viewpoint of scratch resistance, the refractive index is 1 Particles with a low refractive index of less than .17 do not hold. The refractive index of the inorganic fine particles can be measured with an Abbe refractometer (manufactured by Atago Co., Ltd.).

  The amount of the second inorganic fine particles is preferably 10 to 60% by mass of the first resin component, more preferably 15 to 55% by mass, and particularly preferably 20 to 50% by mass. If the amount is too large or too large, the film becomes weak. If the amount is too large, there are particles unevenly distributed in the lower portion of the cured layer, and the effect of reducing the reflectivity is reduced.

  Small inorganic fine particles may be used in combination as the second inorganic fine particles. The particle size of the small-sized inorganic fine particles is preferably 1 nm to 20 nm, more preferably 5 nm to 15 nm, and particularly preferably 8 nm to 15 nm. Use of such inorganic fine particles is preferable in terms of raw material costs and a retaining agent effect.

Inorganic fine particles are treated with physical surface treatment such as plasma discharge treatment or corona discharge treatment in order to stabilize dispersion in the dispersion or coating solution, or to improve the affinity and binding properties with the binder component. Chemical surface treatment with a surfactant, a coupling agent, or the like may be performed. Of these, the use of a coupling agent is particularly preferred. As the coupling agent, an alkoxy metal compound (eg, titanium coupling agent, silane coupling agent) is preferably used. Of these, silane coupling treatment is particularly effective.
The coupling agent is used as a surface treatment agent for the second inorganic fine particles, particularly the inorganic fine particles of the low refractive index layer in the case of forming the low refractive index layer, in order to perform a surface treatment in advance before preparing the coating liquid for the layer. It is preferable to add it as an additive at the time of preparing the layer coating solution, and to add it to the layer.
The inorganic fine particles are preferably dispersed in the medium in advance before the surface treatment in order to reduce the load of the surface treatment.

  The second inorganic fine particles preferably have a smaller surface free energy than the first inorganic fine particles. In order to control the surface free energy with the surface treatment agent, a fluorine-containing organosilane compound, a hydrolyzate of the organosilane, A partial condensate of the hydrolyzate of organosilane is preferably used. An example of a specific compound is shown below.

  In addition to the surface treatment with the fluorine-containing compound, the second inorganic fine particles are also preferably used in combination with the surface treatment agent used for the surface treatment of the first inorganic fine particles. In the present invention, the mass% of the fluorine-containing compound in the surface treatment agent for the second inorganic fine particles is preferably 5% or more and 100% or less, and more preferably 15% or more and 90% or less. By using the surface treatment agent in combination, it becomes easy to adjust the surface free energy of the second inorganic fine particles, and it is possible to impart the binding property to the curable resin.

Further, the surface free energy of the second inorganic fine particles is lower than the surface free energy of the first inorganic fine particles, and the difference between the two is 5 mN / m or more. From the viewpoint of uneven distribution, it is more preferably 7 mN / m or more and 50 mN / m, further preferably 10 mN / m or more and 40 mN / m. By setting it in this range, both particles are separated from the same coating solution and a layer is easily formed.
When the coating composition is used as a composition for forming each layer used in the optical film or antireflection film of the present invention, for example, in the case of a composition for forming a low refractive index layer, the second inorganic fine particles have a low refractive index. Inorganic fine particles suitably used in the rate layer can be used.
The blending ratio of the second inorganic fine particles in the coating composition can be adjusted in accordance with the content of the inorganic fine particles in each layer when the coating composition is used as the composition for forming each layer.

<Organic solvent>
As the organic solvent used in the present invention, it is possible to dissolve or disperse each component, to easily form a uniform surface in the coating process and the drying process, to ensure liquid storage stability, and to have an appropriate saturated vapor pressure. It is possible to use various solvents selected in view of the above.
Two or more kinds of solvents can be mixed and used. In particular, from the viewpoint of drying load, the main component is a solvent having a boiling point of 100 ° C. or lower at normal pressure and room temperature, and a small amount of solvent having a boiling point of 100 ° C. or higher for adjusting the drying speed (100 mass of solvent having a boiling point of 100 ° C. or lower). 1 to 50 parts by mass, more preferably 2 to 40 parts by mass, and particularly preferably 3 to 30 parts by mass) of a solvent having a boiling point of 100 ° C. or higher. By using at least two kinds of organic solvents having different boiling points, it becomes easy to disperse the lower part of the inorganic fine particles and to separate the binder.

  Examples of the solvent having a boiling point of 100 ° C. or lower include hydrocarbons such as hexane (boiling point 68.7 ° C.), heptane (98.4 ° C.), cyclohexane (80.7 ° C.), benzene (80.1 ° C.), Halogenated carbonization such as dichloromethane (39.8 ° C), chloroform (61.2 ° C), carbon tetrachloride (76.8 ° C), 1,2-dichloroethane (83.5 ° C), trichloroethylene (87.2 ° C) Hydrogens, diethyl ether (34.6 ° C), diisopropyl ether (68.5 ° C), dipropyl ether (90.5 ° C), ethers such as tetrahydrofuran (66 ° C), ethyl formate (54.2 ° C), Esters such as methyl acetate (57.8 ° C.), ethyl acetate (77.1 ° C.), isopropyl acetate (89 ° C.), acetone (56.1 ° C.), 2-butanone (methyl ether) Ketones such as Luketone, 79.6 ° C, methanol (64.5 ° C), ethanol (78.3 ° C), 2-propanol (82.4 ° C), 1-propanol (97.2 ° C), etc. Alcohols, cyano compounds such as acetonitrile (81.6 ° C.), propionitrile (97.4 ° C.), carbon disulfide (46.2 ° C.), and the like. Of these, ketones and esters are preferable, and ketones are particularly preferable. Among the ketones, 2-butanone is particularly preferable.

  Examples of the solvent having a boiling point of 100 ° C or higher include, for example, octane (125.7 ° C), toluene (110.6 ° C), xylene (138 ° C), tetrachloroethylene (121.2 ° C), chlorobenzene (131.7 ° C), Dioxane (101.3 ° C.), dibutyl ether (142.4 ° C.), isobutyl acetate (118 ° C.), cyclohexanone (155.7 ° C.), 2-methyl-4-pentanone (same as MIBK, 115.9 ° C.), Examples thereof include 1-butanol (117.7 ° C.), N, N-dimethylformamide (153 ° C.), N, N-dimethylacetamide (166 ° C.), dimethyl sulfoxide (189 ° C.) and the like. Cyclohexanone and 2-methyl-4-pentanone are preferable.

  Another preferred example of using two or more kinds of organic solvents is to use two kinds of solvents having a difference in boiling point greater than a specific value. The difference between the boiling points of the two solvents is preferably 25 ° C. or higher, particularly preferably 35 ° C. or higher, and further preferably 50 ° C. or higher. A large difference in boiling points facilitates the uneven distribution of the inorganic fine particles and the separation of the binder.

  The blending ratio of the organic solvent is preferably added so that the solid content concentration is 2 to 30% by mass, more preferably 3 to 20% by mass, and more preferably 5 to 15% by mass. It is particularly preferable to add them as described above. If the solid content concentration is too low, it takes time to dry, and there is a concern that film thickness unevenness due to drying is likely to occur.If the solid content concentration is too high, uneven distribution of particles does not occur sufficiently, the coating amount decreases, There is concern that uneven coating tends to occur.

  In the coating composition of the present invention, other additives can be added and used in addition to the above-described components. Examples of the other additives that can be used in the present invention include the following additives.

<Leveling agent>
Various leveling agents can be used for the purpose of preventing unevenness. Specifically, as the leveling agent, a fluorine-based leveling agent or a silicone-based leveling agent is preferable, and in particular, a fluorine-based leveling agent is preferable because of its high unevenness preventing ability.
The leveling agent is preferably an oligomer or a polymer rather than a low molecular compound.

  Hereinafter, a preferred fluorine-based leveling agent as the leveling agent will be described. The silicone leveling agent will be described later.

As the fluorine leveling agent, a polymer having a fluoroaliphatic group is preferable, and a polymer of a repeating unit (polymerization unit) corresponding to the monomer (i) below or a repeating unit corresponding to the monomer (i) below. An acrylic resin, a methacrylic resin, and a copolymer with a vinyl monomer copolymerizable therewith are useful, including (polymerized unit) and a repeating unit (polymerized unit) corresponding to the monomer (ii) below. Examples of such monomers include Polymer Handbook 2nd ed. , J .; Brandrup, Wiley Interscience (1975) Chapter 2, Pages 1-483 can be used.
For example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. I can give you.

  (I) Fluoroaliphatic group-containing monomer represented by the following general formula 1

General formula 1

In the general formula 1, R ¹ represents a hydrogen atom, a halogen atom or a methyl group, preferably a hydrogen atom or a methyl group. X represents an oxygen atom, a sulfur atom or —N (R ¹² ) —, more preferably an oxygen atom or —N (R ¹² ) —, and still more preferably an oxygen atom. R ¹² represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms which may have a substituent, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and further preferably a hydrogen atom or a methyl group. R _f represents —CF ₃ or —CF ₂ H.
M in the general formula 1 represents an integer of 1 to 6, more preferably 1 to 3, and still more preferably 1.
N in the general formula 1 represents an integer of 1 to 11, more preferably 1 to 9, and still more preferably 1 to 6. R _f is preferably —CF ₂ H.
In addition, two or more kinds of polymer units derived from the fluoroaliphatic group-containing monomer represented by the general formula 1 may be contained in the fluorine-based polymer as a constituent component.

  (Ii) Monomer represented by the following general formula 2 copolymerizable with the above (i)

General formula 2

In the general formula 2, R ¹³ represents a hydrogen atom, a halogen atom or a methyl group, a hydrogen atom, more preferably a methyl group. Y represents an oxygen atom, a sulfur atom or —N (R ¹⁵ ) —, more preferably an oxygen atom or —N (R ¹⁵ ) —, and still more preferably an oxygen atom. R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and still more preferably a hydrogen atom or a methyl group.
R ¹⁴ is a linear, branched or cyclic alkyl group having 1 to 60 carbon atoms which may have a substituent, or an aromatic group which may have a substituent (for example, phenyl group or naphthyl). Group). The alkyl group may include a poly (alkyleneoxy) group. Furthermore, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms is more preferable, and a linear or branched alkyl group having 1 to 10 carbon atoms is very preferable.

  The amount of the fluoroaliphatic group-containing monomer represented by the above general formula 1 used for the production of a preferred fluoropolymer is 10% by mass or more, preferably 50% by mass based on the total amount of the monomer of the fluoropolymer. % Or more, More preferably, it is 70-100 mass%, More preferably, it is the range of 80-100 mass%.

Hereinafter, although the specific structural example of a preferable fluorine-type polymer is shown, it is not this limitation.
In addition, the number in a formula shows the molar ratio of each monomer component. Mw represents a mass average molecular weight.

  The amount of polymerized units of the fluoroaliphatic group-containing monomer constituting the fluoropolymer is preferably more than 10% by mass, more preferably 50 to 100% by mass, and the viewpoint of preventing unevenness of the light scattering layer In view of the above, it is most preferably 75 to 100% by mass, and most preferably 50 to 75% by mass when a low refractive index layer is applied on the light scattering layer. (Described in all polymer units constituting the fluoropolymer)

  The silicone leveling agent will be described. Examples of the silicone-based leveling agent include polydimethylsiloxane having various substituents such as oligomers such as ethylene glycol and propylene glycol, and the side chain and the terminal of the main chain are modified. KF-96 manufactured by Shin-Etsu Chemical Co., Ltd. X-22-945.

In addition, a nonionic surfactant having a hydrophobic group composed of dimethylpolysiloxane and a hydrophilic group composed of polyoxyalkylene can also be preferably used.
Specific examples of these nonionic surfactants include, for example, Nippon Unicar Co., Ltd., silicone surfactants SILWET L-77, L-720, L-7001, L-7002, L-7604, Y-7006, FZ-2101, FZ-2104, FZ-2105, FZ-2110, FZ-2118, FZ-2120, FZ-2122, FZ-2123, FZ-2130, FZ-2154, FZ-2161, FZ-2162, FZ- 2163, FZ-2164, FZ-2166, FZ-2191, and SUPERSILWET SS-2801, SS-2802, SS-2803, SS-2804, SS-2805, and the like.
In addition, as a preferable structure of the nonionic surfactant in which the hydrophobic group is composed of dimethylpolysiloxane and the hydrophilic group is composed of polyoxyalkylene, a dimethylpolysiloxane structure portion and a polyoxyalkylene chain are alternately and repeatedly bonded. A linear block copolymer is preferred, and JP-A-6-49486 can be referred to.
Specific examples thereof include, for example, silicone surfactants ABN SILWET FZ-2203, FZ-2207, FZ-2208 and the like manufactured by Nippon Unicar Co., Ltd.

  The amount of the fluorine-containing leveling agent and silicone leveling agent added to the coating solution is preferably 0.001% by mass to 1.0% by mass, more preferably 0.01% by mass to 0.2% by mass. It is.

The preferred weight average molecular weight of the fluoropolymer is preferably 3000 to 100,000, more preferably 5,000 to 80,000.
Furthermore, the preferable addition amount of a fluorine-type polymer is the range of 0.001-5 mass% with respect to a coating liquid, Preferably it is the range of 0.005-3 mass%, More preferably, it is 0.01-1 It is the range of mass%. If the addition amount of the fluorine-based polymer is less than 0.001% by mass, the effect is insufficient, and if it exceeds 5% by mass, the coating film may not be sufficiently dried or the performance as a coating film (for example, reflectance) , May have an adverse effect on the scratch resistance).

A thickener can be used to adjust the viscosity of the coating solution.
The term “thickener” as used herein means one that increases the viscosity of the liquid by adding it.

Examples of such thickeners include, but are not limited to:
Poly-ε-caprolactone poly-ε-caprolactone diol poly-ε-caprolactone triol polyvinyl acetate poly (ethylene adipate)
Poly (1,4-butylene adipate)
Poly (1,4-butylene glutarate)
Poly (1,4-butylene succinate)
Poly (1,4-butylene terephthalate)
polyethylene terephthalate)
Poly (2-methyl-1,3-propylene adipate)
Poly (2-methyl-1,3-propylene glutarate)
Poly (neopentyl glycol adipate)
Poly (neopentyl glycol sebacate)
Poly (1,3-propylene adipate)
Poly (1,3-propylene glutarate)
Polyvinyl butyral Polyvinyl formal Polyvinyl acetal Polyvinyl propanal Polyvinyl hexanal Polyvinyl pyrrolidone Polyacrylic acid ester Polymethacrylic acid ester Cellulose acetate Cellulose propionate Cellulose acetate butyrate

  In addition, known viscosity adjustments such as layered compounds such as smectite, mica, bentonite, silica, montmorillonite described in JP-A-8-325491, and sodium polyacrylate, JP-A-10-219136 ethylcellulose, polyacrylic acid, organic clay, etc. An agent or a thixotropic agent can be used. As the thixotropic agent, those obtained by organically treating a layered compound having a particle size of 0.3 μm or less are particularly preferable. A particle size of 0.1 μm or less is more preferable. The particle size of the layered compound can be considered as the length of the long axis. Usually, it is suitable to set it as about 1-10 mass parts with respect to 100 mass parts of ultraviolet curable resin.

[Underlayer]
The underlayer of the layer formed from the coating composition preferably contains the second resin component and / or the first inorganic fine particles contained in the coating composition. By containing at least one of these two components, adhesion between layers is improved, scratch resistance is improved, and inorganic fine particles are easily unevenly distributed in the layer formed from the coating composition. be able to.

[Optical film]
The optical film of the present invention comprises a first resin component having a surface free energy of 30 mN / m or less, a second resin component curable with the first resin component, and an average particle size of 2 nm on a transparent support. The first resin component and / or the second resin component is an optical film having an ionizing radiation-curable functional group, the first resin component and / or the second resin component having a cured layer containing the first inorganic fine particles of 100 nm or less. One inorganic fine particle is unevenly distributed under the cured layer, and the cured layer has an upper layer and a lower layer having different refractive indexes.
This will be described in more detail below.

  The fact that “the first inorganic fine particles are unevenly distributed under the hardened layer” can be confirmed by observing a cross section of the optical film with a transmission electron microscope (TEM). Another object of the present invention is to form a two-layer structure of an upper layer and a lower layer having different refractive indexes in a pseudo manner by the inorganic fine particles being unevenly distributed in the lower portion of the cured layer. Formation of a two-layer structure with different refractive indexes is performed by measuring the spectral reflectance of an optical film, changing the refractive index and thickness of each layer of the interference pattern, performing theoretical calculations of the reflectance, and measuring the measured spectral reflectance data. And can be clarified by fitting. That is, in the case of a two-layer configuration of an upper layer and a lower layer having different refractive indexes, the measurement result and the spectral reflectance curve do not match unless calculation is performed with the two layers having different refractive indexes.

[Configuration of optical film]
As described above, the optical film of the present invention is an optical film having the above-mentioned cured layer on a transparent support. The antireflection film of the present invention has a low refractive index layer as the outermost layer of the optical film, and the low refractive index layer and preferably a high refractive index layer adjacent thereto are preferably the cured layer. Is preferred. In the optical film of the present invention, the cured layer serves as a plurality of functional layers, and may further have other functional layers as required in addition to the low refractive index layer. Next, the layers constituting the optical film of the present invention will be described.
As a preferred embodiment of the optical film of the present invention, a configuration example of an antireflection film will be described. FIG. 1 is a cross-sectional view schematically showing a layer structure of a multilayer antireflection film having excellent antireflection performance. The antireflection film shown in FIG. 1 includes a transparent support 1, a layer having hard coat properties (hereinafter, hard coat layer) 2, a medium refractive index layer 3, a high refractive index layer 4, and a low refractive index layer (outermost layer) 5. In this order. The transparent support 1, the medium refractive index layer 3, the high refractive index layer 4, and the low refractive index layer 5 desirably have refractive indexes that satisfy the following relationship.

  Refractive index of high refractive index layer> refractive index of medium refractive index layer> refractive index of transparent support> refractive index of low refractive index layer

  In the layer configuration as shown in FIG. 1, as described in JP-A-59-50401, the medium refractive index layer is represented by the following formula (I), the high refractive index layer is represented by the following formula (II), and the low refractive index. The layer preferably satisfies the following formula (III) in that an antireflection film having more excellent antireflection performance can be produced.

Formula (I)
(Hλ / 4) × 0.7 <n3d3 <(hλ / 4) × 1.3

  In formula (I), h is a positive integer (generally 1, 2 or 3), n3 is the refractive index of the medium refractive index layer, and d3 is the layer thickness (nm) of the medium refractive index layer. . λ is the wavelength (nm) of visible light, and is a value in the range of 380 to 680 nm.

Formula (II)
(Iλ / 4) × 0.7 <n4d4 <(iλ / 4) × 1.3

  In formula (II), i is a positive integer (generally 1, 2 or 3), n4 is the refractive index of the high refractive index layer, and d4 is the layer thickness (nm) of the high refractive index layer. . λ is the wavelength (nm) of visible light, and is a value in the range of 380 to 680 nm.

Formula (III)
(Jλ / 4) × 0.7 <n5d5 <(jλ / 4) × 1.3

  In Formula (III), j is a positive odd number (generally 1), n5 is the refractive index of the low refractive index layer, and d5 is the layer thickness (nm) of the low refractive index layer. λ is the wavelength (nm) of visible light, and is a value in the range of 380 to 680 nm.

In the layer configuration as shown in FIG. 1, it is particularly preferable that the middle refractive index layer satisfies the following formula (IV), the high refractive index layer satisfies the following formula (V), and the low refractive index layer satisfies the following formula (VI). .
Here, λ is 500 nm.

Formula (IV)
(Λ / 4) × 0.80 <n3d3 <(λ / 4) × 1.00
Formula (V)
(Λ / 2) × 0.75 <n4d4 <(λ / 2) × 0.95
Formula (VI)
(Λ / 4) × 0.95 <n5d5 <(λ / 4) × 1.05

The reflectance of the antireflection film of the present invention is preferably 1.5% or less, and more preferably 1.0% or less. It is more preferably 0.7% or less, particularly preferably 0.5% or less. When obtaining a low reflectance, since layers having different refractive indexes are laminated, the color can be adjusted by adjusting the refractive index and the film thickness to maintain the quality. The color of the antireflection film of the present invention is preferably | a ^* | ≦ 10, | b ^* | ≦ 10, particularly preferably | a ^* | ≦ 7, | b ^* | ≦ 7, | a ^* | ≦ 5, | B ^* | ≦ 5 is more preferable, | a ^* | ≦ 4 and | b ^* | ≦ 4 are particularly preferable.

[Transparent support]
The support for the film of the present invention is not particularly limited, such as a transparent resin film, a transparent resin plate, a transparent resin sheet, or transparent glass. Transparent resin films include cellulose acylate films (for example, cellulose triacetate film (refractive index 1.48), cellulose diacetate film, cellulose acetate butyrate film, cellulose acetate propionate film), polyethylene terephthalate film, polyethersulfone. Film, polyacrylic resin film, polyurethane resin film, polyester film, polycarbonate film, polysulfone film, polyether film, polymethylpentene film, polyetherketone film, (meth) acrylonitrile film, polymer having alicyclic structure (Norbornene resin (Arton: trade name, manufactured by JSR, amorphous polyolefin (ZEONEX: trade name, Nippon The thickness of the support is usually about 25 μm to 1000 μm, preferably 25 μm to 200 μm, more preferably 30 μm to 150, and more preferably 30 to 150 μm. More preferably, it is 90 μm.
Any width of the support can be used, but from the viewpoint of handling, yield, and productivity, a width of 100 to 5000 mm is usually used, preferably 800 to 3000 mm, and preferably 1000 to 2000 mm. More preferably.
The surface of the support is preferably smooth, and the average roughness Ra is preferably 1 μm or less, preferably 0.0001 to 0.5 μm, and 0.001 to 0.1 μm. Is more preferable.
The transparent support is preferably a plastic film. Examples of the plastic film include cellulose esters (eg, triacetylcellulose, diacetylcellulose, propionylcellulose, butyrylcellulose, acetylpropionylcellulose, nitrocellulose) and polyolefins (eg, polypropylene, polyethylene, polymethylpentene, triacetylcellulose, In addition, since polyolefin has a small retardation and high optical uniformity, it is preferable for use as a polarizing plate. In particular, when used in a liquid crystal display device, triacetyl cellulose is preferable.

[Hard coat layer]
The film of the present invention is preferably provided with a hard coat layer on one surface of the transparent support in order to impart the physical strength of the film.

  The refractive index of the hard coat layer in the present invention is preferably in the range of 1.48 to 1.75, more preferably 1.49 to 1, from the optical design for obtaining an antireflection film. .65, and more preferably 1.50 to 1.55. In the present invention, the refractive index of the hard coat layer is preferably in this range from the viewpoints of reflectance, color, unevenness and cost.

From the viewpoint of imparting sufficient durability and impact resistance to the film, the thickness of the hard coat layer is usually about 0.5 μm to 50 μm, preferably 1 μm to 30 μm, more preferably 2 μm. ˜20 μm, most preferably 3 μm to 15 μm. The thickness of the hard coat layer is preferably in the above range from the viewpoint of curling, productivity, and cost.
The strength of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in the pencil hardness test. More preferably, it is 5H or more.
Furthermore, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

  In the optical film of the present invention, haze caused by surface scattering (hereinafter referred to as surface haze) is preferably 0.3% to 20%, particularly preferably 0.5% to 10%, and 0 It is preferably 5% to 5%, particularly preferably 0.5 to 2%. When the surface haze is too large, the bright room contrast is deteriorated, and when it is too small, the reflection is deteriorated.

The optical film of the present invention preferably has a haze due to internal scattering (hereinafter referred to as internal haze) of 0% to 60%, more preferably 1% to 40%. It is particularly preferably 10% to 35%, and more preferably 15% to 30%. If the internal haze is too large, the front contrast is lowered and the brownishness is increased.
If it is too small, the combination of materials that can be used is limited, and it becomes difficult to match antiglare and other characteristic values, and the cost is high.

  The haze of the hard coat layer varies depending on the function imparted to the antireflection film.

In addition to the function of suppressing the reflectance of the surface, when the anti-glare function is imparted by the surface scattering of the hard coat layer, the surface haze (the value obtained by subtracting the internal haze value from the total haze value. The internal haze value is the film surface). Can be measured by eliminating the unevenness of the film with a material having the same refractive index as the film surface.
) Is preferably 0.1% to 20%, particularly preferably 0.2% to 10%, preferably 0.2% to 5%, particularly preferably 0.2 to 2%. preferable. When the surface haze is too large, the bright room contrast is deteriorated, and when it is too small, the reflection is deteriorated.

In addition, when the hard coat layer contains translucent particles to give internal scattering, the preferred range of internal haze varies depending on the purpose, but due to internal scattering, liquid crystal panel patterns, color unevenness, luminance unevenness, glare, etc. are observed. When making it difficult or providing the function of expanding the viewing angle by scattering, the internal haze value is preferably 0% to 60%, more preferably 1% to 40%, and more preferably 10% to 35%. It is particularly preferable that it is 15% to 30%. If the internal haze is too large, the front contrast is lowered and the brownishness is increased. If it is too small, the combination of materials that can be used is limited, and it becomes difficult to match antiglare and other characteristic values, and the cost is high. On the other hand, when importance is attached to the front contrast, 0% to 30% is preferable, more preferably 1% to 20%, and most preferably 1% to 10%.
The film of the present invention can freely set surface haze and internal haze according to the purpose.

  Moreover, about the surface uneven | corrugated shape of a hard-coat layer, it is preferable that centerline average roughness (Ra) shall be 0.30 micrometer or less. Ra is more preferably 0.01 to 0.20 μm, still more preferably 0.01 to 0.12 μm or less. When Ra is large, there are problems such as white blurring caused by surface scattering, and difficulty in obtaining uniformity of the layer formed on the hard coat layer. In the film of the present invention, the surface unevenness of the hard coat layer is dominant to the surface unevenness of the film, and the center line average roughness of the antireflection film is adjusted by adjusting the center line average roughness of the hard coat layer. It can be set as the said range.

  In order to maintain the sharpness of the image, it is preferable to adjust the clarity of the transmitted image in addition to adjusting the uneven shape of the surface. The transmitted image definition of the antireflection film is preferably 60% or more. The transmitted image clarity is generally an index indicating the degree of blurring of an image reflected through a film, and the larger this value, the clearer and better the image viewed through the film. The transmitted image definition is preferably 80% or more, and more preferably 90% or more.

[High refractive index layer, medium refractive index layer]
The film of the present invention can be provided with a high refractive index layer and a medium refractive index layer to enhance antireflection properties.
In the following specification, the high refractive index layer and the middle refractive index layer may be collectively referred to as a high refractive index layer. In the present invention, “high”, “medium”, and “low” in the high refractive index layer, medium refractive index layer, and low refractive index layer represent the relative refractive index relationship between the layers. In terms of the relationship with the transparent support, the refractive index preferably satisfies the relationship of transparent support> low refractive index layer, high refractive index layer> transparent support.
In the present specification, the high refractive index layer, the middle refractive index layer, and the low refractive index layer may be collectively referred to as an antireflection layer.

  In order to construct an antireflection film by constructing a low refractive index layer on a high refractive index layer, the refractive index of the high refractive index layer is preferably 1.55 to 2.20, more preferably It is 1.60 to 2.00, more preferably 1.65 to 1.90, and most preferably 1.70 to 1.85. The higher the refractive index of the high refractive index layer, the easier it is to reduce the reflectance. However, the color becomes stronger and the amount of inorganic fine particles in the high refractive index layer increases, so that the layer becomes brittle and haze increases. In the present invention, it is preferable to adjust to the above range.

  When an antireflection film is formed by coating a medium refractive index layer, a high refractive index layer, and a low refractive index layer in order from the support, the refractive index of the medium refractive index layer is higher than the refractive index of the low refractive index layer. It adjusts so that it may become a value between the refractive indexes of a refractive index layer. The refractive index of the middle refractive index layer is preferably 1.55 to 1.80, and the refractive index difference between the low refractive index layer and / or the high refractive index layer is preferably 0.08 or more, and 0.10 or more. Is particularly preferred.

  The high refractive index layer and the medium refractive index layer used in the present invention contain a binder (for example, ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer) and high refractive index inorganic fine particles for the purpose of controlling the refractive index. Become.

  The underlayer of the layer formed from the coating composition preferably contains the second resin component and / or the first inorganic fine particles contained in the coating composition. By containing at least one of these two components, adhesion between layers is improved, scratch resistance is improved, and inorganic fine particles are easily unevenly distributed in the layer formed from the coating composition. be able to.

  In a preferred embodiment of the present invention, a coating composition containing the first resin component, the second resin component, and the first inorganic fine particles is applied on the high refractive index layer or the middle refractive index layer. The low refractive index layer and the high refractive index layer are formed simultaneously. From the viewpoint of improving the adhesion between layers, improving the scratch resistance, and facilitating the uneven distribution of the first inorganic fine particles, the binder of the high refractive index layer or the middle refractive index layer is a second resin component, a high refractive index. As the inorganic fine particles, the first inorganic fine particles are preferably used.

  The film thickness of the high refractive index layer can be appropriately designed depending on the application. The high refractive index layer is preferably 30 to 200 nm, more preferably 50 to 170 nm, and particularly preferably 60 to 150 nm. In the present invention, the film thickness can be obtained together with the refractive index by fitting by optical calculation of the spectral reflectance.

The haze of the high refractive index layer is preferably as low as possible. It is preferably 5% or less, more preferably 3% or less, and particularly preferably 1% or less.
The high refractive index layer is preferably constructed directly on the transparent support or via another layer.

  In the case of forming the middle refractive index layer in the present invention, it is more preferable to form the hard coat layer and the middle refractive index layer by one coating. That is, when a coating composition containing both components used for forming the hard coat layer and the medium refractive index layer is used, and when applying, drying and curing, the high refractive index inorganic fine particles used for forming the medium refractive index layer are This can be achieved by making the surface portion unevenly distributed. In order to make the high refractive index inorganic fine particles unevenly distributed on the surface, it is preferable to make the surface free energy of the inorganic fine particles smaller than the surface free energy of the binder. It is preferably 2 mN / m or less, more preferably 4 mN / m or more.

  The surface free energy of the inorganic fine particles can be controlled by surface treatment with a surface treatment agent. Although there is no restriction | limiting in particular in a surface treating agent, It is preferable to select and use it according to the kind of binder from the above-mentioned surface treating agent.

[Transparent conductive layer]
The optical film of the present invention is preferably provided with a transparent conductive layer for the purpose of preventing static electricity from the viewpoint of preventing static electricity on the film surface. The transparent conductive layer is effective when there is a demand for lowering the surface resistance value from the display side or when dust on the surface or the like becomes a problem. As a method of forming the transparent conductive layer, for example, a method of applying a conductive coating liquid containing conductive particles and a reactive curable resin, or a metal or metal oxide that forms a transparent film is deposited or sputtered. And a known method such as a method of forming a conductive thin film. In the case of coating, the method is not particularly limited, and an optimum method is selected from known methods such as roll coating, gravure coating, bar coating, extrusion coating, etc., depending on the characteristics of the coating liquid and the coating amount. You can do it. The transparent conductive layer can be formed on the transparent support or the hard coat layer directly or via a primer layer that strengthens the adhesion with them.

The thickness of the transparent conductive layer is preferably from 0.01 to 10 μm, more preferably from 0.03 to 7 μm, still more preferably from 0.05 to 5 μm. When used in a layer close to the outermost layer, sufficient antistatic properties can be obtained even if the film is thin. The surface resistance of the transparent conductive layer is preferably from 10 ⁵ ~10 ¹² Ω / sq, more preferably from 10 ⁵ ~10 ⁹ Ω / sq, it is 10 ⁵ ~10 ⁸ Ω / sq Most preferred. The surface resistance of the transparent conductive layer can be measured by a four probe method.

It is preferable that the transparent conductive layer is substantially transparent. Specifically, the haze of the transparent conductive layer is preferably 10% or less, more preferably 5% or less, still more preferably 3% or less, and most preferably 1% or less. preferable. The transmittance of light having a wavelength of 550 nm is preferably 50% or more, more preferably 60% or more, still more preferably 65% or more, and most preferably 70% or more.
The transparent conductive layer preferably has excellent strength, and the specific antistatic layer has a pencil hardness of 1 kg (as defined in JIS-K-5400), preferably H or higher. More preferably, it is more preferably 3H or more, and most preferably 4H or more.

  In the present invention, the conductive layer is preferably formed by using conductive inorganic oxide fine particles in the medium refractive index layer and / or the high refractive index layer. As the conductive inorganic oxide fine particles, conductive inorganic oxide fine particles among those described in the first inorganic fine particles can be used.

[Low refractive index layer]
In order to reduce the reflectance of the film, the optical film of the present invention is provided with a low refractive index layer as the uppermost layer of the optical film, and the low refractive index layer and the high refractive index layer adjacent thereto are the cured layers. It is preferable.

The refractive index of the low refractive index layer is preferably 1.20 to 1.46, more preferably 1.30 to 1.40, and particularly preferably 1.33 to 1.38.
The thickness of the low refractive index layer is preferably 50 to 200 nm, and more preferably 70 to 100 nm. In the present invention, the film thickness can be obtained together with the refractive index by fitting by optical calculation of the spectral reflectance. The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, and most preferably 1% or less.
The strength after forming the low refractive index layer is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test under a 500 g load. More preferably, it is 5H or more.
Further, in order to improve the antifouling performance of the optical film, it is preferable that the contact angle of water on the surface is 90 degrees or more. More preferably, it is 95 degrees or more, and particularly preferably 100 degrees or more. The dynamic friction coefficient of the surface of the low refractive index layer is preferably 0.03 to 0.30.

  The low refractive index layer can be formed using a curable composition. The low refractive index layer used in the present invention contains a binder and / or low refractive index inorganic fine particles. In the present invention, a low refractive index layer and a high refractive index layer are formed simultaneously from a coating composition containing at least the first resin component, the second resin component, and the first inorganic fine particles. Further, second inorganic fine particles are also preferably used. That is, the binder is not particularly limited as the first resin component and the second resin component, and the low refractive index inorganic fine particles, but the second inorganic fine particles are preferably used.

  In the present invention, a fluorine-containing polymer is preferably used as a binder for the low refractive index layer from the viewpoint of chemical resistance and productivity. As the fluorine-containing polymer, either a thermosetting type or an ionizing radiation curable type can be used as described above. Fluoropolymers are ionizing radiation-cured when forming a high-refractive index layer and a low-refractive index layer at the same time, and in order to increase the affinity and bonding with the components of the high-refractive index layer and to improve the scratch resistance of the antireflection film. A mold is particularly preferred. When the thermosetting type is used, it is preferable to simultaneously use other binder components having both a thermosetting type and an ionizing radiation curable type crosslinkable group. That is, it is more preferable that the first resin component and / or the second resin component have an ionizing radiation curable functional group, and both the first resin component and the second resin component have an ionizing radiation curable functional group. It is particularly preferable to have a plurality of ethylenically unsaturated groups.

  For the purpose of imparting properties such as dust resistance and antistatic properties, a known cationic surfactant or a dustproof agent such as a polyoxyalkylene compound, an antistatic agent, or the like can be appropriately added. These dustproofing agent and antistatic agent may contain the structural unit as a part of the function in the above-mentioned silicone compound or fluorine compound. When these are added as additives, it is preferably added in the range of 0.01 to 20% by mass of the total solid content of the low refractive index layer, more preferably in the range of 0.05 to 10% by mass. Particularly preferred is 0.1 to 5% by mass. Examples of preferred compounds include, but are not limited to, Dainippon Ink Co., Ltd., MegaFace F-150 (trade name), Toray Dow Corning Co., Ltd., SH-3748 (trade name), and the like. Do not mean.

[Step of applying an outermost layer comprising at least two layers]
In the method for producing an optical film of the present invention, in the step of applying the outermost layer composed of at least two layers, a coating composition capable of simultaneously forming at least two outermost layers (the outermost layer multilayer simultaneous forming coating composition) is used. The at least two outermost layers are not particularly limited, but preferably a composition capable of forming two outermost layers, more preferably two outermost layers of a low refractive index layer and a high refractive index layer. Composition. The coating composition contains both the component contained in the low refractive index layer and the component contained in the high refractive index layer, but the first resin component, the second resin component, A coating composition containing the first inorganic fine particles and the organic solvent is preferable, and the second inorganic fine particles are also preferably used.
The coating composition is capable of forming a cured layer by curing, and the coating composition has a refractive index in which the first inorganic fine particles are unevenly distributed in the lower portion of the cured layer. Different upper and lower layers can be formed. The first inorganic fine particles are unevenly distributed in the lower part of the layer, and the proportion of the inorganic fine particles in the high refractive index layer is preferably 60% or more, more preferably 70% or more, and 80% or more. Is more preferable. The existence state of the inorganic fine particles can be observed with a TEM (transmission electron microscope) in the section of the optical film. For example, the existence ratio in the high refractive index layer can be obtained from the ratio of inorganic fine particles present below the average position of the interface between the upper layer and the lower layer. If the interface is not straight, draw the center line to make the interface. When the proportion of the inorganic fine particles is low in the high refractive index layer, the reflectance of the optical film is small and unevenness is likely to occur.

  The second inorganic fine particles are preferably present in a large amount in the upper part of the layer, and more preferably unevenly distributed. It is preferable that the second inorganic fine particles exist mainly in the low refractive index layer. The proportion of the low refractive index inorganic fine particles present in the low refractive index layer is preferably 20% or more, more preferably 30% or more, and even more preferably 30% or more. The presence state of the inorganic fine particles can be confirmed by the same method as described above.

[Method for forming optical film]
Next, the manufacturing method of the optical film of this invention is demonstrated.
The method for producing an optical film of the present invention comprises a step of applying a hard coat layer or a composition for forming each layer of a hard coat layer and a medium refractive index layer on a transparent support, and further for forming at least two outermost layers. A step of applying the composition is preferably used. It is particularly preferable not to go through a step of winding up the transparent support applied between the two steps.
Preferably, the step of applying the hard coat layer, or the hard coat layer and the medium refractive index layer is a step of extruding onto a support using a throttle die, or a step of extruding onto a support simultaneously from a coater having two throttles. It is.
Preferably, after the step of applying the hard coat layer, or the hard coat layer and the medium refractive index layer, and the step of applying at least two outermost layers, further drying and curing steps are performed. Have times.
Preferably, the above-described coating composition of the present invention is used in at least one step of coating at least two outermost layers.

  In some cases, a plurality of layers may be formed in addition to the two surface layers. However, these layers may be fed, layered, and wound up as many times as necessary to form each layer one by one. However, all the layers are formed in one step by providing a set of coating stations and drying and curing zones in the same number as the number of layers between the time when the transparent support is fed and the time of winding. This is advantageous in terms of productivity and cost.

Since the optical film or antireflection film of the present invention forms two surface layers by one coating, the number of coating stations and drying / curing zone sets can be reduced by one, and a great merit is obtained in terms of equipment. It is done. For example, when four layers of a hard coat layer, a medium refractive index layer, a high refractive index layer, and a low refractive index layer are formed on a transparent support, the high refractive index layer and the low refractive index are formed by using the technique of the present invention. It is possible to form two surface layers of the index layer at the same time, and further to form a hard coat layer and a medium refractive index layer at the same time. It is only necessary to arrange two sets of zones, which is very effective.
Hereinafter, each step will be further described in detail.

  In the application of the present invention, it is more preferable to apply using a throttle die having a plurality of throttles. For example, when four layers of a hard coat layer, a medium refractive index layer, a high refractive index layer, and a low refractive index layer are formed on a transparent support, a throttle die having two throttles is used. Four layers are formed by extruding a coating composition for simultaneously forming two surface layers of a low refractive index layer and a coating composition for simultaneously forming a hard coat layer and a medium refractive index layer onto a transparent support from separate throttles. Even with a coating machine having only one coating station and one set of drying and curing zones, four layers can be formed by one coating, which has a further great effect.

The cured layer (two outermost layers, preferably a high refractive index layer and a low refractive index layer, and in another embodiment, a hard coat layer and a medium refractive index layer) in the optical film of the present invention is the coating composition of the present invention described above. In addition, functional layers other than the cured layer can be formed by the following coating methods using the respective coating liquids for forming, but are not limited to this method.
Dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar coating method, gravure coating method or extrusion coating method (die coating method) (see US Pat. No. 2,681,294), micro gravure coating method, etc. Known methods are used, among which the microgravure coating method and the die coating method are preferable, and the die coating method is particularly preferable.

  The micro gravure coating method used in the present invention is a gravure roll having a diameter of about 10 to 100 mm, preferably about 20 to 50 mm and engraved with a gravure pattern on the entire circumference, below the support and in the transport direction of the support. The gravure roll is rotated in reverse with respect to the gravure roll, the excess coating liquid is scraped off from the surface of the gravure roll by a doctor blade, and a fixed amount of the coating liquid is removed from the support in a position where the upper surface of the support is in a free state. The coating method is characterized in that the coating liquid is transferred onto the lower surface for coating.

[Process of extruding onto a support using a throttle die]
In order to supply the film of the present invention with high productivity, an extrusion method (die coating method) is preferably used. In particular, a die coater that can be preferably used in a region with a small amount of wet coating (20 cc / m ² or less) such as a hard coat layer or an antireflection layer will be described below.

{Configuration of die coater}
FIG. 2 is a cross-sectional view of a coater using a throttle die (hereinafter also referred to as “slot die”) embodying the present invention. The coater 10 is applied to the web W supported by the backup roll 11 and continuously applied from the slot die 13 as a bead 14a to form a coating film 14b on the web W.

  Inside the slot die 13, a pocket 15 and a slot 16 are formed. The pocket 15 has a curved section and a straight section, and may be substantially circular or semicircular. The pocket 15 is a liquid storage space for the coating liquid extended in the width direction of the slot die 13 with its cross-sectional shape, and the length of the effective extension is generally equal to or slightly longer than the coating width. The supply of the coating liquid 14 to the pocket 15 is performed from the side surface of the slot die 13 or from the center of the surface opposite to the slot opening 16a. The pocket 15 is provided with a stopper that prevents the coating liquid 14 from leaking out.

  The slot 16 is a flow path of the coating liquid 14 from the pocket 15 to the web W, and has a cross-sectional shape in the width direction of the slot die 13 similarly to the pocket 15, and the opening 16a located on the web side is generally Using a width regulating plate (not shown), the width is adjusted to be approximately the same as the coating width. The angle between the slot tip of the slot 16 and the tangent in the web running direction of the backup roll 11 is preferably 30 ° or more and 90 ° or less.

  The tip lip 17 of the slot die 13 where the opening 16a of the slot 16 is located is tapered, and the tip is a flat part 18 called a land. In the land 18, the upstream side in the traveling direction of the web W with respect to the slot 16 is referred to as an upstream lip land 18 a and the downstream side is referred to as a downstream lip land 18 b.

FIG. 3 shows a cross-sectional shape of the slot die 13 in comparison with a conventional one, (A) shows the slot die 13 of the present invention, and (B) shows a conventional slot die 30. In the conventional slot die 30, the distance between the upstream lip land 31a and the web of the downstream lip land 31b is equal. Reference numeral 32 denotes a pocket, and 33 denotes a slot. On the other hand, in the slot die 13 of the present invention, the downstream side lip land length I _LO is shortened, whereby the wet film thickness of 20 μm or less can be applied with high accuracy.

The land length I _UP of the upstream lip land 18a is not particularly limited, but is preferably used in the range of 500 μm to 1 mm. The land length I _LO of the downstream lip land 18b is not less than 30 μm and not more than 100 μm, preferably not less than 30 μm and not more than 80 μm, more preferably not less than 30 μm and not more than 60 μm. If the land length I _LO of the downstream lip is shorter than 30 μm, the edge or land of the tip lip is likely to be chipped, streaks are likely to occur in the coating film, and consequently application is impossible. In addition, it becomes difficult to set the position of the wetting line on the downstream side, and the coating liquid tends to spread on the downstream side. It has been conventionally known that this spreading of the coating solution on the downstream side means that the wetting line is not uniform, and a defective shape such as a streak is caused on the coating surface. On the other hand, when the land length I _LO of the downstream lip is longer than 100 μm, the bead itself cannot be formed, so that it is impossible to apply the thin layer.

Further, the downstream lip land 18b has an overbite shape closer to the web W than the upstream lip land 18a. Therefore, the degree of decompression can be lowered, and a bead suitable for thin film coating can be formed. The difference in distance between the downstream lip land 18b and the web W of the upstream lip land 18a (hereinafter referred to as overbit length LO) is preferably 30 μm or more and 120 μm or less, more preferably 30 μm or more and 100 μm or less, and most preferably 30 μm. It is 80 μm or less. When the slot die 13 has an overbite shape, the gap _GL between the tip lip 17 and the web W indicates the gap between the downstream lip land 18b and the web W.

FIG. 4 is a perspective view showing a slot die and its periphery in a coating process in which the present invention is implemented.
On the opposite side of the web W in the direction of travel, the decompression chamber 40 is installed at a position where it does not come into contact with the bead 14a so that sufficient decompression adjustment can be performed. The decompression chamber 40 includes a back plate 40a and a side plate 40b for maintaining its operating efficiency, and there are gaps G _B and G between the back plate 40a and the web W and between the side plate 40b and the web W, respectively. _S exists.

FIG. 5 is a cross-sectional view showing the vacuum chamber 40 and the web W that are close to each other. The side plate and the back plate may be integrated with the chamber main body as shown in FIG. 9, or may be structured to be fastened to the chamber with screws so that the gap can be appropriately changed. In any structure, portions that are actually opened between the back plate 40a and the web W and between the side plate 40b and the web W are defined as gaps G _B and G _S , respectively. The gap G _B between the back plate 40a and the web W of the decompression chamber 40, when the vacuum chamber 40 is placed under the web W and the slot die 13 as shown in FIG. 8, the uppermost end of the back plate 40a to the web W Indicates the gap.

Is preferably placed in the gap G _B between the back plate 40a and the web W is larger than the gap G _L between the end lip 17 and the web W of the slot die 13, beads vicinity due to the eccentricity of the backup roll 11 thereby The change in the degree of decompression can be suppressed. For example, when the gap G _L between the end lip 17 and the web W of the slot die 13 is 30μm or more 100μm or less, the gap G _B between the back plate 40a and the web W is preferably 100μm or 500μm or less.

[Material and accuracy]
The longer the length in the web traveling direction of the tip lip on the traveling direction side of the web, the more disadvantageous it is for bead formation. It becomes unstable. Therefore, it is preferable that the fluctuation width in the slot die width direction is within 20 μm.
Further, when the material of the tip lip of the slot die is made of a material such as stainless steel, the length of the slot die tip lip in the web running direction is set to 30 to 100 μm as described above. Even within this range, the accuracy of the tip lip cannot be satisfied. Therefore, in order to maintain high processing accuracy, it is important to use a cemented carbide material as described in Japanese Patent No. 2817053. Specifically, at least the tip lip of the slot die is preferably made of a cemented carbide formed by bonding carbide crystals having an average particle size of 5 μm or less. Cemented carbides include carbide crystal particles such as tungsten carbide (hereinafter referred to as WC) bonded by a bonding metal such as cobalt, and other bonding metals include titanium, tantalum, niobium, and mixed metals thereof. Can also be used. The average particle size of the WC crystal is more preferably 3 μm or less.
In order to realize high-precision coating, the length of the land on the web traveling direction side of the tip lip and the variation in the slot die width direction of the gap with the web are also important factors. It is desirable to achieve a combination of these two factors, that is, straightness within a range in which the fluctuation range of the gap can be suppressed to some extent. Preferably, the straightness of the tip lip and the backup roll is set so that the fluctuation width of the gap in the slot die width direction is 5 μm or less.

[Application speed]
By achieving the accuracy of the backup roll and the tip lip as described above, the coating method preferably used in the present invention has high film thickness stability during high-speed coating. Furthermore, since the coating method is a pre-measuring method, it is easy to ensure a stable film thickness even during high-speed coating. With respect to a coating solution of a low coating amount, the coating method can be applied at high speed with good film thickness stability. Although coating is possible by other coating methods, the dip coating method inevitably causes vibration of the coating liquid in the liquid receiving tank, and stepped unevenness is likely to occur. In the reverse roll coating method, stepped unevenness is likely to occur due to eccentricity and deflection of the roll related to coating. Moreover, since these coating methods are post-measuring methods, it is difficult to ensure a stable film thickness. From the viewpoint of productivity, it is preferable to apply the die coating method at 25 m / min or more.

[Step of simultaneously extruding onto a support from a coater having two or more throttles and / or slides]
Except for using a coater having two throttles as described below, the process is almost the same as the process of extruding using the throttle die described above. By using such a coater having two or more throttles and / or slides, productivity can be further increased.

  The form of the coating head used for simultaneous coating is shown in FIG. Another sliding portion may be provided on the coating head shown in FIGS. 6 (A) to 6 (C). When applying a hard-coat layer and a medium refractive index layer simultaneously, FIG. 6 (A) is preferable. In this case, three layers of a hard coat layer, a medium refractive index layer, and (two layers) outermost layer may be applied simultaneously.

[Dry]
After the coating composition has been applied directly onto the substrate film or via other layers, it is conveyed in a web to a heated zone to dry the solvent. In this case, the temperature of the drying zone is preferably 25 ° C. to 140 ° C., the first half of the drying zone is relatively low temperature, and the second half is preferably relatively high temperature. However, it is preferably below the temperature at which components other than the solvent contained in the coating composition of each layer start to volatilize. For example, some of the commercially available photo radical generators used in combination with ultraviolet curable resins volatilize around several tens of percent within a few minutes in warm air at 120 ° C. Some acrylate monomers and the like undergo volatilization in warm air at 100 ° C. In such a case, it is preferable that it is below the temperature at which components other than the solvent contained in the coating composition of each layer start to volatilize as described above.

The drying wind after applying the coating composition of each layer on the base film is in the range of 0.1 to 2 m / sec on the surface of the coating film while the solid content concentration of the coating composition is 1 to 50%. In order to prevent unevenness in drying, it is preferable.
After coating the coating composition of each layer on the base film, the temperature difference between the transport roll and the base film in contact with the surface opposite to the base film coating surface in the drying zone is within 0 ° C to 20 ° C. Then, drying unevenness due to heat transfer unevenness on the transport roll can be prevented, which is preferable.

[Curing]
After the solvent drying zone, the coating is cured by passing through a zone where the coating is cured by ionizing radiation and / or heat on the web. For example, if the coating film is UV curable, it is to cure each layer by irradiating an irradiation amount of ultraviolet rays of 10mJ / cm ² ~1000mJ / cm ² by an ultraviolet lamp preferred. At that time, the irradiation distribution in the width direction of the web is preferably 50 to 100%, more preferably 80 to 100%, including both ends with respect to the central maximum irradiation. Further, when it is necessary to purge the nitrogen gas or the like to reduce the oxygen concentration in order to promote surface hardening, the oxygen concentration is preferably 5% or less, particularly preferably 0.01% to 5%. In particular, the oxygen concentration of the low refractive index layer is preferably 0.1% or less, particularly preferably 0.05% or less, and particularly preferably 0.02% or less. The distribution in the width direction is preferably 2% or less in terms of oxygen concentration.

  When two or more layers are to be formed, if the first layer cure rate (100-residual functional group content) is less than 100%, a second layer is provided thereon and cured by ionizing radiation and / or heat. In this case, it is preferable that the curing rate of the first layer is higher than that before the second layer is provided, because the adhesion between the two layers is improved.

[Protective film for polarizing plate]
When the antireflection film of the present invention is used in a liquid crystal display device, a low refractive index layer is provided in order to use the antireflection film as a surface protective film for a polarizing film (protective film for a polarizing plate) in preparing a polarizing plate. It is preferable to improve the adhesion to the polarizing film containing polyvinyl alcohol as a main component by hydrophilizing the surface of the transparent support opposite to the side, that is, the surface to be bonded to the polarizing film.

As the transparent support, it is particularly preferable to use a triacetyl cellulose film.
As a method for producing a protective film for polarizing plate in the present invention, (1) each of the above-mentioned layers (eg, hard coat layer, medium refractive index layer, two surface layers, etc.) on one surface of a previously saponified transparent support. There are two methods: (2) a method of coating each layer on one side of the transparent support, and then a saponification treatment on the side to be bonded to the polarizing film. Since the surface to which the coat is to be applied is hydrophilized, it is difficult to ensure the adhesion between the support and the hard coat layer, so the method (2) is preferred.

[Saponification] (1) Immersion method This is a technique in which an antireflection film is immersed in an alkaline solution under appropriate conditions, and all surfaces having reactivity with alkali on the entire surface of the film are saponified, and special equipment is provided. Is preferable from the viewpoint of cost. The alkaline liquid is preferably a sodium hydroxide aqueous solution. A preferred concentration is 0.5 to 3 mol / l, particularly preferably 1 to 2 mol / l. The liquid temperature of a preferable alkali liquid is 30-70 degreeC, Most preferably, it is 40-60 degreeC.
The combination of the above saponification conditions is preferably a combination of relatively mild conditions, but can be set according to the material and configuration of the antireflection film and the target contact angle.
After being immersed in the alkaline solution, it is preferable to sufficiently wash with water or neutralize the alkaline component by immersing in a dilute acid so that the alkaline component does not remain in the film.

By saponification treatment, the surface of the transparent support opposite to the surface having the antireflection layer is hydrophilized. The protective film for polarizing plate is used by adhering the hydrophilic surface of the transparent support to the polarizing film.
The hydrophilized surface is effective for improving the adhesiveness with the adhesive layer mainly composed of polyvinyl alcohol.
In the saponification treatment, the lower the contact angle with water on the surface of the transparent support opposite to the side having the low refractive index layer, the better from the viewpoint of adhesion to the polarizing film, while the dipping method simultaneously reduces the low refractive index. Since the surface having the rate layer is damaged by alkali, it is important to set the reaction conditions to the minimum necessary. As an index of the damage received by the antireflection layer due to alkali, particularly when the surface of the transparent support opposite to the side having the antireflection structure layer, that is, the bonding angle of the antireflection film, the contact angle with water is used. When the support is triacetylcellulose, the contact angle is preferably 20 to 50 degrees, preferably 30 to 50 degrees, more preferably 40 to 50 degrees. If it is 50 degrees or more, there is a problem in the adhesion to the polarizing film, which is not preferable. On the other hand, if the angle is less than 20 degrees, the damage received by the antireflection layer is too great, and physical strength and light resistance are impaired.

(2) Alkaline liquid application method As a means for avoiding damage to the antireflection film in the above-described immersion method, the alkaline liquid is applied only on the surface opposite to the surface having the antireflection film under appropriate conditions, heated, washed with water, A drying alkaline solution coating method is preferably used. The application in this case means that an alkali solution or the like is brought into contact only with the surface to be saponified, and at this time, the contact angle with respect to water of the bonded surface of the antireflection film is 10 to 50 degrees. It is preferable to perform a saponification treatment. In addition to the application, it may include spraying, contact with a belt containing liquid, or the like. By adopting these methods, a separate facility and process for applying an alkaline solution are required, which is inferior to the immersion method (1) from the viewpoint of cost. On the other hand, since the alkali solution contacts only the surface to be saponified, the opposite surface can have a layer using a material that is weak against the alkali solution. For example, vapor deposition films and sol-gel films have various effects such as corrosion, dissolution, and peeling due to alkali solution, so it is not desirable to use the immersion method. Is possible.

  In any of the saponification methods (1) and (2) above, since each layer can be formed by unwinding from a roll-shaped support, a series of operations can be performed in addition to the above-described antireflection film production process. You can go. Furthermore, the polarizing plate can be produced more efficiently than the same operation with a single wafer by continuously performing the pasting step with the polarizing plate made of the unwound support.

[Polarizer]
The polarizing plate of the present invention is a polarizing plate having a polarizing film and two protective films for protecting both the front side and the back side of the polarizing film, and at least one of the protective films of the present invention described above. It is an optical film or the antireflection film of the present invention. Hereinafter, an antireflection film will be described as an example.
The polarizing plate of this invention has the antireflection film of this invention in at least one of the protective film (protective film for polarizing plates) of a polarizing film. The transparent support of the antireflection film is adhered to the polarizing film through an adhesive layer made of polyvinyl alcohol, and the protective film of the other polarizing film is adhered to the antireflective film of the polarizing film through the adhesive layer. It adheres to the main surface opposite to the main surface. The surface main surface opposite to the main surface bonded to the polarizing film of the other protective film has an adhesive layer.
By using the antireflection film of the present invention as a protective film for a polarizing plate, a polarizing plate having physical strength and an excellent antireflection function can be produced, and the cost can be greatly reduced.
Further, by preparing a polarizing plate using the antireflection film of the present invention as one of the protective films for polarizing plates and an optical compensation film having optical anisotropy described later as the other protective film of the polarizing film, Thus, it is possible to produce a polarizing plate that improves the contrast in the bright room of the liquid crystal display device and can greatly widen the viewing angle in the vertical and horizontal directions and in the oblique direction.

[Optical compensation film]
The optical compensation film (retardation film) can improve the viewing angle characteristics of the liquid crystal display screen.
A known film can be used as the optical compensation film, but it has optical anisotropy made of a compound having a discotic structural unit described in JP-A-2001-100042 in terms of widening the viewing angle. An optical compensation film having a layer, wherein the angle formed by the discotic compound and the support varies with the distance from the transparent support, is preferable.
The angle preferably increases as the distance from the support surface side of the optically anisotropic layer increases.
When the optical compensation film is used as a protective film for the polarizing film, the surface on the side to be bonded to the polarizing film is preferably saponified, and is preferably performed according to the saponifying process.
Also, an aspect in which the optically anisotropic layer further contains a cellulose ester, an aspect in which an alignment layer is formed between the optically anisotropic layer and the transparent support, and an optical compensation film having the optically anisotropic layer It is also preferable that the transparent support has an optically negative uniaxial property, has an optical axis in the normal direction of the transparent support surface, and further satisfies the following conditions.
20 ≦ {(nx + ny) / 2−nz} × d ≦ 400
In the above conditional expression, nx is the refractive index in the slow axis direction (direction in which the refractive index is maximum) in the film plane, and ny is the fast axis direction in the film plane (direction in which the refractive index is minimum). Where nz is the refractive index in the thickness direction of the film, and d is the thickness of the optical compensation layer.

[Image display device]
The image display device of the present invention has at least one of the above-described optical film of the present invention, the antireflection film of the present invention, or the polarizing plate of the present invention.
As an image display device having the antireflection film of the present invention, a liquid crystal display device (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), a cathode tube display device (CRT), a field emission display (FED), Surface electric field display (SED) etc. are mentioned. Examples of the image display device having the polarizing plate having the antireflection film of the present invention include image display devices such as a liquid crystal display device (LCD) and an electroluminescence display (ELD). In the image display device of the present invention, the polarizing plate having the antireflection film of the present invention is used by bonding directly to the glass of the liquid crystal cell of the liquid crystal display device or through another layer.

The polarizing plate using the antireflection film used in the present invention includes twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optically compensated bend cell ( It can be preferably used for a transmissive, reflective, or transflective liquid crystal display device in a mode such as OCB).
Further, when used in a transmissive or transflective liquid crystal display device, it is used in combination with a commercially available brightness enhancement film (a polarized light separation film having a polarization selective layer, such as D-BEF manufactured by Sumitomo 3M Co., Ltd.). Thus, a display device with higher visibility can be obtained.
Further, by combining with a λ / 4 plate, it can be used to reduce the reflected light from the surface and inside as a polarizing plate for reflective liquid crystal or a surface protective plate for organic EL display.

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

(Synthesis of perfluoroolefin copolymer (P1))

Perfluoroolefin copolymer (P1)

Into an autoclave with a stirrer made of stainless steel having an internal volume of 100 ml, 40 ml of ethyl acetate, 14.7 g of hydroxyethyl vinyl ether and 0.55 g of dilauroyl peroxide were charged, and the inside of the system was deaerated and replaced with nitrogen gas. Further, 25 g of hexafluoropropylene (HFP) was introduced into the autoclave and the temperature was raised to 65 ° C. The pressure when the temperature in the autoclave reached 65 ° C. was 0.53 Mpa (5.4 kg / cm ² ). The reaction was continued for 8 hours while maintaining the temperature, and when the pressure reached 0.31 MPa (3.2 kg / cm ² ), the heating was stopped and the mixture was allowed to cool. When the internal temperature dropped to room temperature, unreacted monomers were driven out, the autoclave was opened, and the reaction solution was taken out. The obtained reaction solution was poured into a large excess of hexane, and the polymer was precipitated by removing the solvent by decantation. Further, this polymer was dissolved in a small amount of ethyl acetate and reprecipitated twice from hexane to completely remove the residual monomer. After drying, 28 g of polymer was obtained. Next, 20 g of the polymer was dissolved in 100 ml of N, N-dimethylacetamide, and 11.4 g of acrylic acid chloride was added dropwise under ice cooling, followed by stirring at room temperature for 10 hours. Ethyl acetate was added to the reaction solution, washed with water, the organic layer was extracted and concentrated, and the resulting polymer was reprecipitated with hexane to obtain 19 g of a perfluoroolefin copolymer (P1). The resulting polymer had a refractive index of 1.421.

(Preparation of sol solution a)
A stirrer, a reactor equipped with a reflux condenser, 120 parts of methyl ethyl ketone, 100 parts of acryloyloxypropyltrimethoxysilane (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts of diisopropoxyaluminum ethyl acetoacetate were added and mixed. Thereafter, 30 parts of ion-exchanged water was added and reacted at 60 ° C. for 4 hours, and then cooled to room temperature to obtain sol solution a. The mass average molecular weight was 1600, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 100%. Further, from the gas chromatography analysis, the raw material acryloyloxypropyltrimethoxysilane did not remain at all.

(Preparation of silica dispersion A)
Hollow silica fine particle sol (Isopropyl alcohol silica sol, average particle diameter 40 nm, shell thickness 6 nm, silica concentration 20% by mass, silica particle refractive index 1.30, prepared by changing the size according to Preparation Example 4 of JP-A-2002-79616 ) 500 parts, 8 parts acryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.), 2 parts tridecafluorooctyltrimethoxysilane (manufactured by GE Toshiba Silicone Co., Ltd.), and diisopropoxyaluminum ethyl acetate 1 After adding 5 parts and mixing, 9 parts of ion-exchanged water was added. After reacting at 60 ° C. for 8 hours, the mixture was cooled to room temperature, and 1.8 parts of acetylacetone was added.
While adding cyclohexanone to 500 g of this dispersion so that the silica content was almost constant, solvent substitution was performed by distillation under reduced pressure at a pressure of 20 kPa. There was no generation of foreign matter in the dispersion, and the viscosity when adjusted to a solid content concentration of 22% by mass with cyclohexanone was 9 mPa · s at 25 ° C. The amount of isopropyl alcohol remaining in the obtained dispersion A was analyzed by gas chromatography and found to be 1.0%.

(Adjustment of dispersion B)
500 g of a methyl isobutyl ketone dispersion (solid content concentration 20 mass%) of ZrO ₂ particles having a particle diameter of 15 nm, 10 g of acryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.), and diisopropoxyaluminum ethyl acetate After adding 5 g and mixing, 3 g of ion-exchanged water was added. After reacting at 60 ° C. for 8 hours, the mixture was cooled to room temperature, and 1.8 g of acetylacetone was added to prepare dispersion B. 31.4 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) is added to Dispersion B and distilled under reduced pressure at a pressure of 20 kPa to produce a solution having a solid content concentration of 62%. did. 0.5 g of a photopolymerization initiator (Irgacure 184, manufactured by Ciba Geigy) and 0.5 g of a photopolymerization initiator (Irgacure 904, manufactured by Ciba Geigy) are added and dissolved by stirring. Dispersion B having a partial concentration of about 61% and a ZrO ₂ content of about 70% in the solid content was prepared.

(Adjustment of coating liquid A for hard coat layer)
306 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) was dissolved in a mixed solvent of 16 parts by mass of methyl ethyl ketone and 220 parts by mass of cyclohexanone. After adding 7.5 parts by mass of a photopolymerization initiator (Irgacure 184, manufactured by Ciba Geigy) to the resulting solution and stirring until dissolved, 450 parts by mass of MEK-ST (average particle size of 10 to 20 nm, solid content) Add a methyl ethyl ketone dispersion of SiO ₂ sol having a concentration of 30% by mass (manufactured by Nissan Chemical Co., Ltd.), stir to obtain a mixture, and filter through a polypropylene filter (PPE-03) with a pore size of 3 μm for a hard coat layer. A coating solution A was prepared. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet rays was 1.50.

(Preparation of coating liquid B for hard coat layer)
71.2 g of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (PET-30, manufactured by Nippon Kayaku Co., Ltd.) and 2.9 g of a polymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) , 0.1 g of fluorine-based surface modifier (SP-13), 11.8 g of silane coupling agent (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to methyl isobutyl ketone, and 60 by air disperser. Stir for minutes to completely dissolve the solute. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet rays was 1.52. 13.7 g of a crosslinked poly (acryl-styrene) particle having an average particle size of 3.5 μm (copolymerization composition ratio = 50/50, refractive index 1.536) was dispersed with a Polytron disperser at 10,000 rpm for 20 minutes and 30% methyl isobutyl. It added as a ketone dispersion liquid, methyl isobutyl ketone and methyl ethyl ketone were added, solid content concentration was adjusted to 45 mass%, and it stirred for 10 minutes with the air disper. The mass ratio of methyl isobutyl ketone and methyl ethyl ketone was adjusted to 9: 1.
The mixed solution was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution B for hard coat layer.

(Adjustment of coating solution for medium refractive index layer)
57 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) and 3 g of a photopolymerization initiator (Irgacure 904, manufactured by Ciba Geigy) are added to 65.6 g of the dispersion B, and the solid content Methyl isobutyl ketone was added so that the concentration was 3.5% by weight and stirred for 10 minutes. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet rays was 1.62.
The mixture was filtered through a polypropylene filter (PPE-03) having a pore size of 3 μm to prepare a coating solution for a medium refractive index layer.

(Adjustment of coating liquid A for the surface layer 2 layers)
Dispersion B132g, perfluoroolefin copolymer (P1) 50.8g, reactive silicone X-22-164B (trade name; manufactured by Shin-Etsu Chemical Co., Ltd.) 1.6g, photopolymerization initiator (Irgacure 907 (trade name) ), 1.6 g of Ciba Specialty Chemicals Co., Ltd.), cyclohexanone and methyl ethyl ketone were added to a solid content concentration of 5.4%, and the mixture was stirred for 10 minutes. The mass ratio of methyl ethyl ketone and cyclohexanone was adjusted to 9: 1.
The mixed solution was filtered through a polypropylene filter (PPE-03) having a pore diameter of 3 μm to prepare a surface layer two-layer coating solution A.

(Adjustment of coating liquid B for surface layer 2 layers)
In 132 g of the dispersion B, 780.2 g of a heat-crosslinkable fluorine-containing polymer having a refractive index of 1.44 containing polysiloxane and a hydroxyl group (JTA113, solid content concentration 6%, manufactured by JSR Corporation), sol solution a 7.3 g, 0.5 g of photopolymerization initiator A was added, and cyclohexanone was added to methyl ethyl ketone so that the solid content concentration was 5.4%, followed by stirring for 10 minutes. The mass ratio of methyl ethyl ketone and cyclohexanone was adjusted to 9: 1.
The mixed solution was filtered through a polypropylene filter (PPE-03) having a pore size of 3 μm to prepare a surface layer 2-layer coating solution B.

(Initiator A)

(Adjustment of coating liquid C for the surface layer 2 layers)
Dispersion B132g, perfluoroolefin copolymer (P1) 30g, dispersion A120g, reactive silicone X-22-164B (trade name; manufactured by Shin-Etsu Chemical Co., Ltd.) 1.6g, sol liquid a 7.2g, light 1.6 g of a polymerization initiator (Irgacure 907 (trade name), manufactured by Ciba Specialty Chemicals Co., Ltd.) was added, methyl ethyl ketone and cyclohexanone were added to a solid content concentration of 5.4%, and the mixture was stirred for 10 minutes. The mass ratio of methyl ethyl ketone and cyclohexanone was adjusted to 8: 2.
The mixed solution was filtered through a polypropylene filter (PPE-03) having a pore size of 3 μm to prepare a surface layer 2-layer coating solution C.

(Adjustment of surface layer 2 layer coating solution D)
Surface layer 2 layer coating solution D was prepared in the same manner as surface layer 2 layer coating solution A, except that all solvents were methyl ethyl ketone.

(Adjustment of coating solution E for surface layer 2 layers)
Instead of perfluoroolefin copolymer (P1) and reactive silicone X-22-164B (trade name; manufactured by Shin-Etsu Chemical Co., Ltd.), the same amount of dipentaerythritol pentaacrylate and dipenta as the total amount of the two components The surface layer 2 layer coating solution E was prepared in the same manner as the surface layer 2 layer coating solution A, except that a mixture of erythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.) was used.

[Example 1]
(Preparation of antireflection film)
(Preparation of antireflection film 1-1A)
To the triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd., refractive index: 1.49) having a thickness of 80 μm, the above-mentioned coating liquid A for hard coat layer was added to a throttle die coater (FIG. 3 (A )) And dried at 100 ° C. for 2 minutes. Next, purging with nitrogen and irradiating with ultraviolet rays of 70 mJ / cm ² under a condition where the oxygen concentration is 0.1%, the coating layer is cured, and a hard coat layer (refractive index: 1.50, film thickness: 6 μm) Formed. Subsequently, the above medium refractive index layer coating solution was applied using a throttle die coater (FIG. 3A), dried at 100 ° C., purged with nitrogen, and the oxygen concentration was adjusted to 0.1%. Under the irradiation, ultraviolet rays were irradiated at 200 mJ / cm ² to cure the coating layer, and an intermediate refractive index layer (refractive index: 1.62, film thickness: 60 nm) was provided. On the medium refractive index layer, the above-mentioned surface layer two-layer coating solution A is applied using a throttle die coater (FIG. 3A), dried at 100 ° C. for 1 minute, and then purged with nitrogen to adjust the oxygen concentration. An antireflection film 1-1A was produced by irradiating with ultraviolet rays of 500 mJ / cm ² under a condition of 0.05%, curing the coating layer, and simultaneously forming a high refractive index layer and a low refractive index layer. The refractive index and the film thickness of the high refractive index layer and the low refractive index layer are as follows. From the fitting of the spectral reflection curve of the formed film, the high refractive index layer has a refractive index of 1.72 and the film thickness is 110 nm. The refractive index was 1.43 and the film thickness was 90 nm, confirming optical separation into two layers.

(Preparation of antireflection film 1-1B)
The surface layer 2 layer coating solution B was used as the surface layer 2 layer coating solution, dried at 100 ° C., then thermally cured at 100 ° C. for 10 minutes, and then purged with nitrogen to have an oxygen concentration of 0.05%. The antireflection film 1-1B was produced by the same method as the antireflection film 1-1A except that the coating layer was cured by irradiating with 500 mJ / cm ² of ultraviolet rays. The refractive index and film thickness of the high refractive index layer and the low refractive index layer formed at the same time from the coating solution for the two surface layers are such that the refractive index of the high refractive index layer is 1. 72, the film thickness: 110 nm, and the low refractive index layer had a refractive index of 1.44 and a film thickness of 90 nm, confirming optical separation into two layers.

(Preparation of antireflection film 1-1C)
An antireflection film 1-1C was produced in the same manner as the antireflection film 1-1A, except that the surface layer 2 layer coating liquid C was used as the surface layer 2 layer coating liquid. The refractive index and film thickness of the high refractive index layer and the low refractive index layer formed at the same time from the coating solution for the two surface layers are such that the refractive index of the high refractive index layer is 1. 72, film thickness: 110 nm, and the low refractive index layer had a refractive index of 1.38 and a film thickness of 95 nm, confirming optical separation into two layers.

(Preparation of antireflection film 1-1D)
An antireflection film 1-1D was produced in the same manner as the antireflection film 1-1A, except that the surface layer 2 layer coating liquid D was used as the surface layer 2 layer coating liquid. The refractive index and film thickness of the high refractive index layer and the low refractive index layer formed at the same time from the coating solution for the two surface layers are such that the refractive index of the high refractive index layer is 1. 69, film thickness: 110 nm, and the low refractive index layer had a refractive index of 1.48 and a film thickness of 90 nm, confirming optical separation into two layers.

(Preparation of antireflection film 1-1E)
An antireflection film 1-1E was produced in the same manner as the antireflection film 1-1A, except that the surface layer 2 layer coating liquid E was used as the surface layer 2 layer coating liquid. Two layers of a high refractive index layer, a low refractive index layer, and a low refractive index layer are not formed from the coating solution for the surface layer, and the refractive index is 1.63 from the fitting of the spectral reflection curve of the formed film. : Only one layer of 200 nm was formed.

(Calculation of surface free energy)
Mixture of perfluoroolefin copolymer (P1) and reactive silicone X-22-164B, thermally crosslinkable fluoropolymer (JTA113, solid content concentration 6%, manufactured by JSR Corporation), dipentaerythritol pentaacrylate, di Each mixture of pentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) was dissolved in MEK, applied, dried and cured to produce a cured product, and the single surface free energy was determined. For the perfluoroolefin copolymer (P1), a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), a photopolymerization initiator having a solid content concentration of 5% ( Irgacure 907 (trade name), manufactured by Ciba Specialty Chemicals Co., Ltd.) was added. Drying and curing conditions were a mixture of perfluoroolefin copolymer (P1) and reactive silicone X-22-164B, a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) ) With respect to the same conditions as when the antireflection film 1-1A was cured on the two surface layers, and with respect to the thermally crosslinkable fluorine-containing polymer (JTA113, solid content concentration 6%, manufactured by JSR Corporation), the antireflection film 1-1B The conditions were the same as those for the two-layer curing. The surface free energy was calculated from the contact angle between water and methylene iodide.
Mixture of perfluoroolefin copolymer (P1) and reactive silicone X-22-164B, thermally crosslinkable fluoropolymer (JTA113, solid content concentration 6%, manufactured by JSR Corporation), dipentaerythritol pentaacrylate and di The surface free energy of each of the mixtures with pentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) was 22.5 mN / m, 22.0 mN / m, and 49.0 mN / m.

  For silica dispersion A and dispersion B, particles were precipitated by centrifuging and decanted, then MEK solvent was added, and ultrasonic waves were applied for 2 minutes with an ultrasonic transmitter. Thereafter, centrifugation, decantation, MEK solvent, and US application were repeated 4 times, and then cast on a washed glass substrate and dried to obtain a thin film sample of oxide fine particles. When the surface free energy was calculated from the contact angle measurement of the sample, the oxide fine particles prepared from the silica dispersion A and the dispersion B were 34.5 mN / m and 52.0 mN / m, respectively.

(Evaluation of antireflection film)
About the obtained film, the following items were evaluated. The results are summarized in Table 1.

(1) Integral reflectance and color The back side of the film is sandpaper and then treated with black ink, and the back side reflection is eliminated, and the spectrophotometer V-550 (manufactured by JASCO Corporation) is used. The integrated reflectance was measured, the average reflectance of 450 to 650 nm was calculated, and the antireflection property was evaluated. Further, the CIE 1976 L ^* a ^* b ^* color space a ^* value and b ^* value representing the color of the specularly reflected light with respect to the 5-degree incident light of the CIE standard light source D65 are calculated from the measured reflection spectrum, and the reflected light The color was evaluated.

(2) Haze The following measurements measured the total haze (H), internal haze (Hi), and surface haze (Hs) of the obtained film.
[1] The total haze value (H) of the film obtained according to JIS-K7136 was measured.
[2] A few drops of silicone oil are added to the front and back surfaces of the obtained film on the low refractive index layer side, and two glass plates having a thickness of 1 mm (micro slide glass product number S 9111, manufactured by MATSANAMI) are used from the front and back. The two glass plates and the obtained film are optically closely attached, and the haze is measured with the surface haze removed, and only silicone oil is sandwiched between two separately measured glass plates. The value obtained by subtracting the haze measured in step 1 was calculated as the internal haze (Hi) of the film.
[3] A value obtained by subtracting the internal haze (Hi) calculated in [2] from the total haze (H) measured in [1] above was calculated as the surface haze (Hs) of the film.

(3) Pencil hardness evaluation Pencil hardness evaluation described in JIS K 5400 was performed as an index of scratch resistance. After conditioning the antireflection film at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, it was evaluated using the 2H-5H test pencil specified in JIS S 6006 at a load of 500 g as follows. Then, the highest hardness that is OK was taken as the evaluation value.
In evaluation of n = 5, there is no scratch to one scratch: OK
In evaluation of n = 5, 3 or more scratches: NG

(4) Steel wool scratch resistance evaluation Steel wool scratch resistance can be used as an index of scratch resistance by conducting a rubbing test under the following conditions using a rubbing tester.
Evaluation environmental conditions: 25 ° C., 60% RH,
Rubbing material: Steel wool (manufactured by Nippon Steel Wool Co., Ltd., Grade No. 0000)
Wrap around the tip (1cm x 1cm) of the scraper of the tester that comes into contact with the sample, and fix the band.
Travel distance (one way): 13cm
Rubbing speed: 13 cm / second,
Load: 200 g / cm ²
Tip contact area: 1 cm × 1 cm, rubbing frequency: 10 reciprocations.
Oily black ink was applied to the back side of the rubbed sample, and scratches on the rubbed portion were visually observed with reflected light, and the following determinations were made.
A: I'm scared of scratches B: I'm worried about scratches C: I'm very worried about scratches

(5) Contact angle measurement As an index of surface contamination resistance, the optical material was conditioned at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, and then the contact angle of pure water was measured to obtain an index of fingerprint adhesion. .

(6) Centerline average roughness The centerline average roughness Ra of the film obtained according to JIS-B0601 was measured.

  Examples 1-1A to 1-1D all showed good antireflection performance. Among 1-1A to 1-1D, the antireflection performance of 1-1D was slightly inferior. Particularly preferred are 1-1A and 1-1C, and most preferred is 1-1C. In Comparative Example 1-E, the value of the integrated reflectance is a value that is difficult to say that the reflection is prevented.

Section TEM photographs of each sample of Examples 1-1A to 1-1E were taken to confirm the presence state of ZrO ₂ particles. In all of Examples 1-1A to 1-1C, the uneven distribution of the lower part was observed, and the part where the particles were present and the part where the particles were not present were clearly separated. In 1-1D, the presence interface of ZrO ₂ particles was wavy compared with 1-1A to 1-1C, and the presence of particles in the high refractive index layer was sparser than 1-1A and 1-1B. 1-1E was not found to be unevenly distributed in the lower part of the ZrO ₂ particles, and was dispersed almost uniformly in the surface layer 2 layer forming layer.

  As a result of taking a section TEM photograph of the sample of Example 1-1C and confirming the presence state of the hollow silica fine particles, the sample was unevenly distributed in the upper part.

An antireflection film 1-2A is prepared in the same manner as the antireflection film 1-A, except that the coating liquid B for the hard coat layer is used instead of the coating liquid A for the hard coat layer of the antireflection film 1-1A. did. The results are summarized in Table 2.

  The antireflection film 1-2A was given a weak antiglare property, and the antireflection performance was further improved than that of 1-1A. Further, an antireflection film having an internal haze of 25.1% and having an effect of improving glare prevention performance when used in a high-definition LCD and viewing angle characteristics of the LCD was obtained.

(Preparation of antireflection film 1-3A)
Using a die coater (FIG. 6 (A)) for simultaneous multilayer coating, the coating liquid A for the antireflection film hard coat layer is extruded from the throttle part, the medium refractive index coating liquid from the slide part, and simultaneously extruded from the throttle die. An antireflection film 1-3A was produced in the same manner as 1-1A, except that it was coated on a transparent support. Drying / curing conditions of the hard coat layer and the middle refractive index layer applied simultaneously with the multilayer were dried at 100 ° C. for 2 minutes, and then irradiated with UV rays at a concentration of 0.1% under a nitrogen purge at 200 mJ / cm ² . . Although the obtained antireflection film 1-3A had an integrated reflectance of 1.3%, which was slightly inferior to 1-1A, good antireflection performance could be efficiently produced. The refractive index and film thickness of the high-refractive index layer and low-refractive index layer formed simultaneously from the surface layer two-layer coating solution are optically separated into two layers by fitting the spectral reflection curve of the formed film. I was able to confirm.

(Preparation of antireflection film 1-4A)
Use a die coater with one more slide part for the simultaneous multi-layer coating die coater (Fig. 6 (A)), apply coating solution for hard coat layer from the throttle part, and apply for medium refractive index layer from the two slide parts, respectively. The antireflection film 1-4A was produced by the same method as 1-1A except that the liquid and the coating liquid A for the surface layer 2 layer were extruded and simultaneously applied onto the transparent support. Drying / curing conditions for the hard coat layer and the middle refractive index layer applied simultaneously with multiple layers were dried at 100 ° C. for 2 minutes, and then irradiated with ultraviolet rays at 500 mJ / cm ² under a nitrogen purge with an oxygen concentration of 0.05%. . Although the obtained antireflection film 1-4A had an integrated reflectance of 1.5%, which was slightly inferior to 1-3A, an antireflection film showing good antireflection performance could be produced efficiently. The refractive index and film thickness of the high-refractive index layer and low-refractive index layer formed simultaneously from the surface layer two-layer coating solution are optically separated into two layers by fitting the spectral reflection curve of the formed film. I was able to confirm.

[Example 2]
(Saponification treatment of antireflection film)
The following processing was performed on each of the samples 1-1A to 1E, 2A, and 3A.
A 1.5 mol / l aqueous sodium hydroxide solution was prepared and kept at 55 ° C. A 0.01 mol / l dilute sulfuric acid aqueous solution was prepared and kept at 35 ° C. The prepared antireflection film was immersed in the aqueous sodium hydroxide solution for 2 minutes, and then immersed in water to sufficiently wash away the aqueous sodium hydroxide solution. Subsequently, after being immersed in the dilute sulfuric acid aqueous solution for 1 minute, it was immersed in water to sufficiently wash away the dilute sulfuric acid aqueous solution. Finally, the sample was thoroughly dried at 120 ° C.
In this way, a saponified antireflection film was produced.

(Preparation of polarizing plate)
80 μm-thick triacetylcellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.), saponified, immersed in 1.5 mol / L, 55 ° C. NaOH aqueous solution for 2 minutes, neutralized and washed with water A polarizing plate is prepared by adhering and protecting a used antireflection film (saponified samples 1-1A to 1E, 2A, 3A, 4A) by adsorbing iodine to polyvinyl alcohol and stretching the polarizer. Produced. These are designated as Samples 2-1A to 1E, 2A, 3A, and 4A.
Moreover, a polarizing plate is produced using the saponified triacetyl cellulose film as a protective film on both sides, and this is designated as Sample 2-5A (Comparative Example).

(Evaluation of polarizing plate)
The produced polarizing plate samples 2-1A to 1E, 2A, 3A, 4A, and 5A were produced as a substitute for the polarizing plate on the viewing side of the liquid crystal television. As the liquid crystal television, “LC-37GD4” (MVA method) manufactured by Sharp Corporation was used.
When samples 2-1A to 1D, 2A, 3A, and 4A, which are examples, were used as polarizing plates, images with little reflection and good contrast were obtained. Moreover, there was no coloration due to the reflection on the surface, and a good image in which black looked black was obtained. When 2-2A was used, the reflection was less due to the antiglare property. In addition, the viewing angle characteristics were improved, and the contrast and gradation characteristics in an oblique 45 degree direction were improved. When Samples 2-E and 5A, which are comparative examples, were used, there was no anti-reflective property, and the reflected image was strongly transferred, adversely affecting the display performance.

[Example 3]
Sample 3-1-A was produced in the same manner as Sample 1-1-A, except that PET with an easy-adhesion layer (Cosmo Shine A4100 manufactured by Toyobo Co., Ltd., film thickness: 188 μm) was used as the transparent support. When the surface film of the 42-inch plasma display (pioneer direct color filter type PDU-42H6A1) without the front plate is peeled off and the sample 3-1A is attached with an adhesive instead, a good display with little reflection Performance was obtained.

[Example 4]
A circularly polarizing plate (Sample 4-1-A) was prepared by laminating a λ / 4 plate with an adhesive on the surface of Sample 1-1-A opposite to the low refractive index layer. When Sample 4-1-A was attached to the surface of the organic EL display with an adhesive so that the low refractive index layer was on the outside, good display performance with little reflection was obtained.

[Example 5]
When Sample 4-1-A was used as a polarizing plate on the surface of a reflective liquid crystal display and a transflective liquid crystal display so that the low refractive index layer was on the outside, good display performance with little reflection was obtained. It was.

[Example 6]
When the sample 4-1-A was affixed on the glass on the surface of the laser display used in Example 3 with an adhesive so that the low refractive index layer was on the outside, the white brightness was reduced, but the contrast was remarkably high. Improved display performance was obtained with less reflection.

[Example 7]
(Preparation of antireflection film 7-1A)
To the 80 μm thick triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd., refractive index: 1.49), the above hard coat layer coating solution B was added to a throttle die coater (FIG. 3 (A )) And dried at 100 ° C. for 2 minutes. Next, purging with nitrogen and irradiating with ultraviolet rays of 70 mJ / cm ² under the condition that the oxygen concentration is 0.1%, the coating layer is cured, and a hard coat layer (refractive index: 1.52, film thickness: 6 μm) Formed. Subsequently, the above surface layer 2 layer coating solution A was applied using a throttle die coater (FIG. 3A), dried at 100 ° C. for 1 minute, and then purged with nitrogen to make the oxygen concentration 0.05%. Under the conditions, ultraviolet rays were irradiated at 500 mJ / cm ² to cure the coating layer, and a high refractive index layer and a low refractive index layer were formed at the same time to produce an antireflection film 7-1A.
The obtained antireflection film 7-1A had an integrated reflectance of 1.0%. The refractive index and the film thickness of the high refractive index layer and the low refractive index layer are as follows. From the fitting of the spectral reflection curve of the formed film, the high refractive index layer has a refractive index of 1.72 and the film thickness is 110 nm. The refractive index was 1.43 and the film thickness was 90 nm, confirming optical separation into two layers.

(Preparation of antireflection film 7-2A)
Using a die coater (Fig. 6 (A)) for simultaneous multi-layer coating, the coating liquid A for the anti-reflection film hard coat layer is extruded from the throttle part, and the coating liquid B for the hard coat layer is extruded from the slide part simultaneously from the throttle die. An antireflection film 7-2A was produced in the same manner as 7-1A, except that it was coated on a transparent support. Drying / curing conditions were as follows: after drying at 100 ° C. for 2 minutes, irradiation with ultraviolet rays of 500 mJ / cm ² was performed under a nitrogen purge with an oxygen concentration of 0.05%.
Although the obtained antireflection film 7-2A had an integrated reflectance of 2.0% and was inferior to 7-1A, a film showing antireflection performance could be produced.

Section TEM photographs of the samples of the antireflection films 7-1A and 7-2A were taken to confirm the presence of ZrO ₂ particles. The 7-1A ZrO ₂ particles segregated into a layer having a thickness of 110 nm 90 nm below the film surface, and corresponded well to the film thickness of 110 nm obtained by fitting the spectral reflection curve.
On the other hand, it was found that the 7-2A ZrO ₂ particles were distributed in a layer form over a thickness of about 500 nm 90 nm below the film surface and diffused into the lower hard coat layer. The antireflection films 1-3A and 1-4A of Example 1 contain ZrO ₂ common to the lower segregation component in the surface layer two-layer coating solution at the time of simultaneous multilayer coating, It is estimated that there is little loss of reflectivity during multilayer coating. On the other hand, since the antireflection film 7-2A of Example 7 does not contain ZrO ₂ common to the lower segregation component in the surface layer two-layer coating liquid during simultaneous multilayer coating, the lower layer coating liquid contains ZrO ₂ particles. It is presumed that the decrease in reflectance at the time of simultaneous multi-layer coating was increased.

DESCRIPTION OF SYMBOLS 1 Transparent support 2 Hard coat layer 3 Medium refractive index layer 4 High refractive index layer 5 Low refractive index layer 10 Coater 11 Backup roll W Web 13 Slot die 14 Coating liquid 14a Bead 14b Coating film 15 Pocket 16 Slot 16a Slot opening part 17 Tip lip 18 Land 18a Upstream lip land 18b Downstream lip land I _UP Land length of upstream lip land 18a I _LO Land length of downstream lip land 18b LO Over bite length (downstream lip land 18b and upstream side (Difference in distance between the lip land 18a and the web W)
G _L End lip 17 and web W gap (downstream lip land 18b and web W gap)
30 the gap G _S side plate 40b and the web W between the conventional slot-die 31a upstream lip land 31b downstream lip land 32 pocket 33 slot 40 vacuum chamber 40a back plate 40b side plate 40c screws G _B back plate 40a and the web W Gap between

The present invention relates to a method for producing a light optical film.

An object of the present invention has a low reflectance, color excellent in scratch resistance in neutral, and the productivity is suitable for mass production, to provide a method for producing an optical fill beam.

As a result of intensive studies to solve the above-described problems, the present inventors have found that the above-described problems can be solved and the object can be achieved, and the present invention has been completed.
That is, the present invention is as follows.
[1] A step of applying a coating composition for forming an upper layer and a lower layer having different refractive indexes on the transparent support and a coating composition for forming a hard coat layer or a medium refractive index layer forming composition on a transparent support and curing. The manufacturing method of the optical film which has a process to do.
A first resin component capable of forming a cured layer having a surface free energy of 30 mN / m or less, a first resin component and a curable second resin component, a first inorganic material having an average particle size of 2 nm to 100 nm particulates, and at least the coating composition containing one organic solvent, said first resin component 及 beauty / or said second resin component has an ionizing radiation-curable functional groups, the coating composition Is a coating composition in which a cured layer is formed by curing, and the first inorganic fine particles are unevenly distributed under the cured layer to form an upper layer and a lower layer having different refractive indexes.
[2] The method for producing an optical film according to the above [1], wherein both the coating composition directly and adjacently applied to the coating composition forming the upper layer and the lower layer having different refractive indexes contain inorganic fine particles.
[3] The method for producing an optical film according to [2], wherein both the coating composition for forming the upper layer and the lower layer having different refractive indexes are directly adjacent to each other and contain the same inorganic fine particles. .
[4] Three coating compositions: a coating composition for forming a hard coat layer, a coating composition for forming a medium refractive index layer, and a coating composition for forming an upper layer and a lower layer having different refractive indexes on a transparent support. The manufacturing method of the optical film as described in any one of said [1]-[3] which has the process of apply | coating simultaneously, and the process of hardening | curing.
[5] A coating composition for forming an upper layer and a lower layer having different refractive indexes is coated on a transparent support simultaneously with a die coater, simultaneously with the coating composition for forming a hard coat layer or the coating composition for forming a medium refractive index layer. The manufacturing method of the optical film as described in any one of said [1]-[4] which has the process and the process of hardening.
[6] A coating composition for forming an upper layer and a lower layer having different refractive indexes,
A first resin component capable of forming a cured layer having a surface free energy of 30 mN / m or less, a first resin component and a curable second resin component, a first inorganic material having an average particle size of 2 nm to 100 nm A coating composition containing fine particles, inorganic fine particles having a refractive index of 1.46 or less, and at least one organic solvent as the second inorganic fine particles, wherein the first resin component and / or the second resin component Has an ionizing radiation curable functional group, and the coating composition is cured to form a cured layer, the first inorganic fine particles are unevenly distributed in the lower part of the cured layer, and the second inorganic fine particles are Coating composition that is unevenly distributed on top of the cured layer to form an upper layer and a lower layer having different refractive indexes
The method for producing an optical film according to any one of the above [1] to [5].
[7] A coating composition for forming an upper layer and a lower layer having different refractive indexes
A first resin component capable of forming a cured layer having a surface free energy of 30 mN / m or less, a first resin component and a curable second resin component, a first inorganic material having an average particle size of 2 nm to 100 nm A coating composition containing fine particles, inorganic fine particles having a refractive index of 1.46 or less, and at least one organic solvent as the second inorganic fine particles, wherein the first resin component and / or the second resin component Has an ionizing radiation curable functional group, and the coating composition is cured to form a cured layer, the first inorganic fine particles are unevenly distributed in the lower part of the cured layer, and the second inorganic fine particles are Coating composition that is unevenly distributed on top of the cured layer to form an upper layer and a lower layer having different refractive indexes
Because
The first resin component is a thermosetting or ionizing radiation curable fluorine-containing compound,
The second inorganic fine particles are surface-treated with a fluorine-containing organosilane compound, a hydrolyzate of the organosilane, or a partial condensate of the hydrolyzate of the organosilane,
The surface free energy of the second resin component is larger than the surface free energy of the first resin component, and the difference between the surface free energy of the first resin component and the surface free energy of the second resin component is 5 mN / m or more,
The surface free energy of the first inorganic fine particles is larger than the surface free energy of the first resin component, and the difference between the surface free energy of the first inorganic fine particles and the surface free energy of the first resin component is: 10 mN / m or more,
The surface free energy of the second inorganic fine particles is smaller than the surface free energy of the first inorganic fine particles, and the difference between the surface free energy of the first inorganic fine particles and the surface free energy of the second inorganic fine particles is: 5 mN / m or more
The manufacturing method of the optical film as described in any one of said [1]-[6].
In addition, although this invention is a manufacturing method of the optical film described in said [1]-[7], the other matter is also described in the specification for reference.

Claims (16)

A first resin component capable of forming a cured layer having a surface free energy of 30 mN / m or less, a first resin component and a curable second resin component, a first inorganic material having an average particle size of 2 nm to 100 nm A coating composition containing fine particles and at least one organic solvent, wherein the first resin component and / or the second resin component has an ionizing radiation curable functional group,
The coating composition is a coating composition in which a cured layer is formed by curing, and the first inorganic fine particles are unevenly distributed under the cured layer to form an upper layer and a lower layer having different refractive indexes.   The coating composition according to claim 1, wherein the first resin component is a thermosetting or ionizing radiation curable fluorine-containing compound.   The fluorine-containing compound has a silicone structure in the molecule, or the coating composition contains a silicone compound having a crosslinkable group and has the same crosslinkable group as the crosslinkable group contained in the silicone compound. 3. The coating composition according to 1 or 2.   The said 1st inorganic fine particle is an inorganic fine particle surface-treated with at least 1 type chosen from a silane coupling agent, its partial hydrolyzate, and its condensate. Coating composition.   The surface free energy of the second resin component is greater than the surface free energy of the first resin component, and the difference between the surface free energy of the first resin component and the surface free energy of the second resin component is 5 mN / It is m or more, The coating composition as described in any one of Claims 1-4.   The surface free energy of the first inorganic fine particles is larger than the surface free energy of the first resin component, and the difference between the surface free energy of the first inorganic fine particles and the surface free energy of the first resin component is 10 mN / It is m or more, The coating composition as described in any one of Claims 1-5.   The coating composition according to any one of claims 1 to 6, comprising inorganic fine particles having a refractive index of 1.46 or less as the second inorganic fine particles.   The surface free energy of the second inorganic fine particles is smaller than the surface free energy of the first inorganic fine particles, and the difference between the surface free energy of the first inorganic fine particles and the surface free energy of the second inorganic fine particles is 5 mN / The coating composition according to claim 7, which is m or more.   The optical film which has a hardened layer formed by hardening | curing the coating composition as described in any one of Claims 1-8 on a transparent support body.   The optical film according to claim 9, wherein the cured layer is a low refractive index layer that is an outermost layer of the optical film and a high refractive index layer adjacent thereto.   It is a polarizing plate which has a polarizing film and two protective films which protect both the front side and back side of this polarizing film, Comprising: At least one of this protective film is an optical film of Claim 9 or 10. Polarizer.   The image display apparatus which has at least 1 of the optical film of Claim 9 or 10, or the polarizing plate of Claim 11.   It is a manufacturing method of the optical film which has a layer formed by hardening | curing a coating composition on a transparent support body, Comprising: The process of apply | coating the coating composition in any one of Claims 1-8, The process of drying, The manufacturing method of the optical film which has this.   The step of applying is a step of applying the coating composition together with the composition for forming a hard coat layer or the composition for forming a medium refractive index layer after feeding the transparent support, and between the formation of each layer The manufacturing method of Claim 13 which does not have a winding-up process.   The step of applying is a step of applying the coating composition together with the composition for forming a hard coat layer or the composition for forming a medium refractive index layer after feeding the transparent support, and forming the hard coat layer The manufacturing method according to claim 13 or 14, which is a step of simultaneously applying at least two of the composition for forming, the medium refractive index layer forming composition, and the coating composition.   The manufacturing method according to claim 13, further comprising a curing step.

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