JP2005283656A - Method for manufacturing antireflection film, antireflection film, polarizing plate and image display device using the film or the plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an antireflection film which improves the transferring effect of embosses in imparting ruggedness on the surface of the antireflection layer of the antireflection film by embossing work and having excellent performance in an antidazzle characteristic and to provide an antireflection film and moreover to provide a polarizing plate and an image display device equipped with the antireflection film. <P>SOLUTION: The manufacturing method of the antireflection film having the antireflection layer consisting of at least one layer on a transparent substrate, has following processes (1) to (4) in order: (1) a process for applying at least one hard coat precursor layer with an easy embossing characteristic on the transparent substrate; (2) a process for applying the antireflection layer on the hard coat precursor layer with easy embossing characteristic and hardening the antireflection layer; (3) a process for forming the ruggedness on an antireflection layer-side film surface with pressing work; and (4) a process for hardening the hard coat precursor layer with easy embossing characteristic by a means different from a means for hardening the antireflection layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antireflection film and a method for producing the same, and more particularly to an antireflection film used for an image display device such as a liquid crystal display device and a method for producing the same.

The antireflection film is provided in various image display devices such as a liquid crystal display device (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), and a cathode ray tube display device (CRT).
As an antireflection film, a multilayer film obtained by laminating a transparent thin film of metal oxide has been conventionally used. The reason for using a plurality of transparent thin films is to prevent reflection of light of various wavelengths. The transparent thin film of metal oxide is 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.
The antireflection film by the PVD method may be formed on a base material having an antiglare property due to surface unevenness depending on applications. Although the parallel light transmittance is lower than that formed on a smooth substrate, the reflection of the background is scattered and reduced by surface irregularities, so it exhibits anti-glare properties and combined with the anti-reflection effect, image formation When applied to an apparatus, the display quality is remarkably improved.
However, this metal oxide transparent thin film has excellent optical properties as an antireflection film, but the formation method by vapor deposition is low in productivity and is not suitable for mass production.

  Therefore, a method of forming an antireflection film by applying inorganic fine particles instead of the vapor deposition method has been proposed. For example, Patent Document 1 discloses an antireflection layer having fine pores and fine inorganic particles. Here, the antireflection layer is formed by coating. The fine pores are formed by performing an activated gas treatment after the application of the layer and releasing the gas from the layer. Patent Document 2 discloses an antireflection film in which a base material, a high refractive index layer, and a low refractive index layer are laminated in this order. The document also discloses an antireflection film in which an intermediate refractive index layer is provided between a substrate and a high refractive index layer. Here, the low refractive index layer is formed by application of a polymer or inorganic fine particles.

  As a means for imparting antiglare properties to the antireflection film by application as described above, a method of applying an antireflection layer on a substrate having surface irregularities, or mat particles for forming surface irregularities in the antireflection layer A method of adding to the above has been studied. However, in the former method, the coating solution of the antireflection layer flows from the convex part to the concave part, resulting in uneven film thickness in the surface, and significantly less antireflection performance compared to the coating film on the smooth surface. There is a problem that gets worse. Further, in the latter method, mat particles having a particle size of about 1 micron or more necessary for expressing sufficient anti-glare properties are embedded in a thin film having a thickness of about 0.1 to 0.3 microns. As a result, there arises a problem of powder falling off of the matte particles.

  In addition, as means for forming irregularities, a hard coat is applied to the undercoat layer formed with irregularities by applying a composition (paint) containing a specific pigment, as described in Patent Document 3 and Patent Document 4, etc. A method for producing a hard coat film having surface irregularities by providing a layer or attaching and transferring a cured coating while forming irregularities is disclosed. There are problems such as complexity and the above-described problems occurring when a functional layer is applied after the formation of irregularities.

  As a countermeasure against this, the applicant of the present application disclosed in Patent Document 5 and Patent Document 6 that the transparent substrate is made uneven as in the past, or mat particles are added to the antireflection layer to form the surface of the antireflection layer. Instead of providing irregularities, a method has been proposed in which an antireflection film provided with an antireflection layer is pressed by a metal embossing roller and a metal backup roller, and the irregularities are transferred to the surface of the antireflection film.

  However, the method of pressing the antireflection film with the embossing roller and the backup roller is that the embossing roller convexity for applying irregularities to the surface of the antireflection layer is antireflection in the process of applying press pressure to the antireflection film. There is a problem of penetrating the film and opening a hole in the antireflection film (hereinafter referred to as opening). As a countermeasure, it is improved to some extent by adjusting the press pressure, but the perforation cannot be solved completely. Also, if the press pressure is reduced until the perforations are eliminated without fail, the unevenness transfer accuracy becomes extremely poor.

Also, since the unevenness due to the embossing roller is mainly formed on the base film, the temperature of the embossing treatment needs to be higher than the glass transition temperature of the base film, and the base material is deformed during processing, There is a problem that handling of the substrate becomes difficult. In addition, the antiglare antireflection film is applied to the surface of a liquid crystal display device and the like, and is used for the purpose of improving its visibility. It is required not to change. However, the concavo-convex shape formed on the antireflection film by embossing has a problem that the antiglare property is lost due to change with the passage of time due to deformation strain remaining on the transparent substrate.
Japanese Patent Publication No. 60-59250 JP 59-50401 A JP 2002-370303 A JP-A-8-112866 JP 2000-275404 A JP 2000-329905 A

  In view of the circumstances concerned, the present invention provides no irregularities on the surface of the antireflection layer of the antireflection film by embossing, and does not cause perforation in the antireflection film, and is used over time at high temperatures and high humidity. It is another object of the present invention to provide a method for producing an antireflection film whose performance does not change. The present invention also provides an antireflection film having excellent antiglare properties and antireflection properties, the performance of which does not easily deteriorate with time, and a polarizing plate and an image display device comprising the antireflection film. The purpose is to provide.

In order to achieve the above object, the present invention provides an easily embossed hard coat precursor layer on a transparent substrate, and after application and curing of the antireflection layer, imparts irregularities by pressing, and further cures the antireflection layer. It has the characteristics in the manufacturing method which hardens this embossing hard-coat precursor layer with another hardening method.
That is, the above object of the present invention is achieved by the following means.

[1] In the production of an antireflection film having an antireflection layer comprising at least one layer on a transparent substrate, the method for producing an antireflection film comprising the following steps (1) to (4) in order: .
(1) A step of coating at least one easily embossable hard coat precursor layer on a transparent substrate;
(2) coating an antireflection layer on the easily embossable hard coat precursor layer and curing the antireflection layer;
(3) a step of forming irregularities on the antireflection layer side film surface by pressing,
(4) A step of curing the easily embossable hard coat precursor layer by means different from the means for curing the antireflection layer.
[2] The antireflection film according to [1], wherein the means for curing the easily embossable hard coat precursor layer, which is a means different from the means for curing the antireflection layer, is electron beam irradiation. Production method.
[3] The method for producing an antireflection film as described in [1] or [2] above, wherein unevenness is formed by pressing with a plate of 0.01 ≦ Ra ≦ 2.0 μm, 5 ≦ RSm ≦ 60 μm. .
[4] The method for producing an antireflection film as described in [1] to [3] above, wherein pressing is performed at a temperature not higher than the glass transition temperature of the transparent substrate.
[5] The surface elastic modulus of the easily embossable hard coat precursor layer after the step (1) is less than 4.5 GPa, and the surface elastic modulus of the easily embossable hard coat cured layer after the step (4) is 4. The method for producing an antireflection film according to the above [1] to [4], which is 5 Gpa or more.
[6] An antireflection film produced by the method according to any one of [1] to [5].
[7] The easily embossed hard coat cured layer obtained by curing the easily embossable hard coat precursor layer contains at least one compound having a repeating unit represented by the following general formula (1) [6] ] Antireflection film of description.
General formula (1)

In the general formula (1), R ² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. P ² is a monovalent group containing an ethylenically unsaturated group, and L ² is a single bond or a divalent linking group.
[8] The antireflection film as described in [6] or [7] above, wherein the arithmetic average roughness (Ra) of the outermost surface opposite to the transparent substrate surface is 0.05 to 0.5 μm .
[9] The antireflection film as described in [6] to [8], wherein the transparent support substantially does not contain a benzotriazole skeleton ultraviolet absorber.
[10] A polarizing plate, wherein the antireflection film according to any one of the above [6] to [9] is used for one of the two protective films of the polarizing plate in the polarizing plate.
[11] An image display device, wherein the antireflection film according to any one of [6] to [9] or the polarizing plate according to [10] is used on an outermost surface of a display.

  According to the present invention, in providing unevenness on the surface of the antireflection layer of the antireflection film by embossing, there is no perforation in the antireflection film, and even at high temperatures and high humidity over time, It is possible to provide an antireflection film whose performance does not change.

  Hereinafter, the manufacturing method of the antireflection film with an antiglare function according to the present invention and preferred embodiments of the antireflection film will be described in detail. In the present specification, the description of “numerical value A” to “numerical value B” indicating physical property values and characteristic values represents the meaning of “numerical value A to numerical value B”.

The antireflection film of the present invention has an easily embossed hard coat cured layer on a transparent substrate, and has at least one antireflection layer on the layer. Furthermore, since the film surface on the side having the antireflection layer has irregularities, it exhibits an antiglare function.
In the method for producing an antireflection film of the present invention, an easily embossable hard coat precursor layer is first coated (applied and dried) on a transparent substrate (step (1)), and then the easily embossed hard coat precursor layer. After applying at least one antireflection layer thereon, the antireflection layer is cured (step (2)). Further, after applying unevenness to the surface of the film having the antireflection layer with respect to the transparent substrate by pressing (step (3)), the embossed hard coat precursor is prepared by means other than the means for curing the antireflection layer. A layer is hardened and desired hardness is provided (process (4)). In addition, hardening of an easily embossable hard-coat precursor layer (process (4)) may be performed during press (process (3)), and desired hardness may be provided.
If the same means is used for curing the antireflection layer and the easy embossing hard coat precursor layer, the hardness of the easy embossing hard coat precursor layer will increase when the antireflection layer is cured, and it is necessary even if embossing is applied. It is difficult to make unevenness. In order to solve this problem, if the pressing pressure is increased and the unevenness is forcibly applied, cracking occurs in the easily embossed hard coat cured layer. On the other hand, since the hardness of the easily embossable hard coat precursor layer is not increased, if the antireflection layer is hardened sufficiently, mixing between layers occurs, and the required optical performance cannot be obtained.
There is no particular limitation as long as the means for curing the antireflection layer and the means for curing the easily embossable hard coat precursor layer after pressing are different, depending on the type of the cured composition forming each layer, ultraviolet rays, electron beams, It can be appropriately selected from active energy ray types such as near ultraviolet rays, visible light, near infrared rays, infrared rays, and X-rays.
In the present invention, after the antireflection layer is cured by ultraviolet irradiation, a means for curing the easily embossable hard coat precursor layer to a desired hardness by electron beam irradiation is preferable. In the case of ultraviolet rays, ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arcs, xenon arcs, metal halide lamps and the like can be used. In the case of electron beam irradiation, energy of 50 to 1000 keV emitted from various electron beam accelerators such as Cockloft Walton type, bandegraph type, resonant transformation type, insulated core transformer type, linear type, dynamitron type, and high frequency type. An electron beam having
The easily embossed hard coat precursor layer may be pre-cured by ultraviolet irradiation, electron beam irradiation or the like before the step (2), and the hardness may be increased stepwise.

  In the method of the present invention, in order to impart antiglare properties, the embossing hard coat precursor layer is pressed and embossed before raising the hardness to the final hardness. Therefore, since the embossing is performed in a state where the hardness of the easy embossing hard coat precursor layer is low, the embossing is easily performed, and it is possible to prevent the formation of holes even when unevenness is provided on the film surface by the embossing. In addition, the unevenness is formed mainly by the deformation of the easily embossed hard coat precursor layer, and the layer is further cured after the embossing process. Can be maintained over time. In addition, since the anti-reflection layer can be applied with the surface of the easily embossed hard coat precursor layer being smooth, the anti-reflection layer having a film thickness as designed can be formed uniformly.

  Hereinafter, the structure and manufacturing method of each layer of the antireflection film having an antiglare function according to the present invention will be described with reference to the drawings as necessary.

[Formation of Easily Embossed Hard Coat Precursor Layer and Easily Embossed Hard Coat Hardened Layer]
A known curable resin can be used for the curable composition used to form the easily embossed hard coat precursor layer, and it contains two or more ethylenically unsaturated groups that are cured by active energy rays in the same molecule. A curable resin or a curable resin containing a ring-opening polymerizable group is preferred. Two kinds of curable resins can be used in combination.

Preferred types of ethylenically unsaturated groups are acryloyl group, methacryloyl group, vinyl group, styryl group and allyl group, and particularly preferably acryloyl group. Note that these curable resins containing two or more ethylenically unsaturated groups in the same molecule may be used alone or in combination.
Examples of the curable resin containing two or more ethylenically unsaturated groups in the same molecule include a curable resin called a polyfunctional (meth) acrylate monomer, urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meta ) An oligomer having a molecular weight of several hundred to several thousands having three or more (meth) acrylic acid ester groups in a molecule called acrylate can be preferably used. In the present specification, “(meth) acrylate”, “(meth) acryloyl” and “(meth) acrylic acid” mean “acrylate or methacrylate”, “acryloyl or methacryloyl” and “acrylic acid or methacrylic acid”. .

  Specific examples of the curable resin having two or more acrylic groups in the same molecule include butanediol diacrylate, hexanediol diacrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate, 1,4-cyclohexane diacrylate, Polyol polyacrylates such as methylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and hydroxyl groups such as polyisocyanate and hydroxyethyl acrylate Urethane acrylate, bisphenol A, etc. obtained by reaction of acrylate containing glycidyl Epoxy acrylates obtained by a reaction such as acrylate, tris (acryloxyethyl) isocyanurate, and the like.

Examples of other curable resins having two or more ethylenically unsaturated groups in the molecule include styrene compounds (for example, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester), 1,4- Examples thereof include divinylcyclohexanone, vinyl sulfone (for example, divinyl sulfone), and acrylamide (for example, methylene bisacrylamide).
Further, as the curable resin and its monomer, for example, those described in “Photocuring Technology Data Book Material” (Technonet Books, Technonet) and the like can be used.

The curable resin containing a ring-opening polymerizable group is preferably a curable resin having a ring structure in which ring-opening polymerization proceeds by the action of a cation, an anion, a radical, etc. Among them, a heterocyclic group-containing curable resin is preferable. . Examples of such curable resins include epoxy compounds, oxetane compounds, tetrahydrofuran compounds, cyclic lactone compounds, cyclic carbonate compounds, cyclic imino ethers such as oxazoline compounds, and the like, and epoxy compounds, oxetane compounds, and oxazoline compounds are particularly preferable.
In the present invention, the curable resin having a ring-opening polymerizable group preferably has two or more ring-opening polymerizable groups in the same molecule, more preferably three or more. In the present invention, two or more curable resins having a ring-opening polymerizable group may be used in combination. In this case, a curable resin having one ring-opening polymerizable group in the same molecule is used as necessary. Can be used together.

  The curable resin having a ring-opening polymerizable group referred to in the present invention is not particularly limited as long as it is a curable resin having a cyclic structure as described above. Preferred examples of such curable resins include monofunctional glycidyl ethers, monofunctional alicyclic epoxies, difunctional alicyclic epoxies, diglycidyl ethers (for example, ethylene glycol diglycidyl ether as glycidyl ethers). Bisphenol A diglycidyl ether), trifunctional or higher glycidyl ethers (trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, glycerol triglycidyl ether, triglycidyl trishydroxyethyl isocyanurate, etc.) Ethers (sorbitol tetraglycidyl ether, pentaerythritol tetraglycyl ether, polyglycidyl ether of cresol novolac resin, phenol novolac Fatty polyglycidyl ether, etc.), cycloaliphatic epoxies (Celoxide 2021P, Celoxide 2081, Epolide GT-301, Epolide GT-401 (above, manufactured by Daicel Chemical Industries), EHPE (Daicel Chemical Industries, Ltd.) ), Phenol novolak resin polycyclohexyl epoxy methyl ether, etc.), oxetanes (OX-SQ, PNOX-1009 (above, manufactured by Toagosei Co., Ltd.), etc.), etc., but the present invention is limited to these. It is not a thing.

  The curable resin having a ring-opening polymerizable group particularly preferably contains a crosslinkable polymer containing a ring-opening polymerizable group in a repeating unit. As such a crosslinkable polymer, an acrylate ester having a ring-opening polymerizable group is preferable. Examples of the ring-opening polymerizable group include monovalent groups including an imino ether ring such as an epoxy ring, an oxetane ring, a tetrahydrofuran ring, a lactone ring, a carbonate ring, and an oxazoline ring, and among these, an epoxy ring and an oxetane are particularly preferable. It is a monovalent group containing a ring and an oxazoline ring. A specific example is a polymer of glycidyl methacrylate.

  In the present invention, a crosslinkable polymer containing a repeating unit represented by the following general formula (1) can also be preferably used as a compound having a plurality of ethylenically unsaturated groups in the molecule, and the crosslinkable composition can be used as a curable composition. It is preferable to contain at least one polymer. Hereinafter, the crosslinkable polymer containing the repeating unit represented by the general formula (1) will be described in detail.

General formula (1)

In the general formula (1), R ² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom or a methyl group. P ² is a monovalent group containing an ethylenically unsaturated group, preferably a monovalent group containing an acryloyl group, a methacryloyl group or a styryl group, and most preferably a monovalent group containing an acryloyl group. L ² is a single bond or a divalent linking group, preferably a single bond, —O—, an alkylene group, an arylene group, and * —COO—, * —CONH—, * — linked to the main chain on the * side. OCO- and * -NHCO-, and two or more of these may be combined.

  Although the preferable specific example of the repeating unit represented by General formula (1) below is shown, this invention is not limited to these.

The crosslinkable polymer containing the repeating unit represented by the general formula (1) may be synthesized by a method in which (a) a corresponding monomer is polymerized to directly introduce an ethylenically unsaturated group; You may synthesize | combine by the method of introduce | transducing an ethylenically unsaturated group into a polymer obtained by superposing | polymerizing the monomer which has a functional group by polymer reaction. Moreover, it can also synthesize | combine combining the method of (a) and (b). Examples of the polymerization reaction include radical polymerization, cationic polymerization, and anionic polymerization. When the method (a) is used, it is necessary to use the difference in polymerizability between the ethylenically unsaturated group consumed by the polymerization reaction and the ethylenically unsaturated group remaining in the crosslinkable polymer.
For example, in the case of using a monovalent group including an acryloyl group and a methacryloyl group among the preferable P ^{2 in} the general formula (1), the polymerization reaction for generating a crosslinkable polymer is set as a cationic polymerization to form the above-mentioned (a). The crosslinkable polymer of the present invention can be obtained by a technique. On the other hand, when P ² is a monovalent group containing a styryl group, gelation is likely to proceed by any of radical polymerization, cationic polymerization, and anionic polymerization. A synthetic polymer.

The easily embossable hard coat precursor layer can be cured to a desired hardness by a means different from the means for curing the antireflection layer after the pressing step after curing the antireflection layer to form an easily embossed hardcoat cured layer. As this curing method, electron beam irradiation is preferred.
When the easily embossable hard coat precursor layer is cured by electron beam irradiation, it is not necessary to add an initiator to the easily embossable hard coat precursor layer, and the easily embossed hard coat precursor layer at the time of curing the antireflection layer. This is preferable because it can suppress curing of the resin and deactivation of the initiator.
Further, the easily embossed hard coat precursor layer may be pre-cured with ultraviolet rays or electron beams before coating the antireflection layer.

For the purpose of increasing the hardness of the easily embossed hard coat cured layer, inorganic and organic fine particles can be added as necessary. Examples of the inorganic fine particles include oxides of at least one metal selected from silicon, zirconium, titanium, aluminum, indium, zinc, tin, and antimony, and BaSO ₄ , CaCO ₃ , talc, and kaolin. The particle size is 100 nm or less, preferably 50 nm or less. An easily embossed hard coat cured layer that does not impair the transparency can be formed by refining the inorganic fine particles to 100 nm or less.
On the other hand, for the purpose of increasing the refractive index of the easily embossed hard coat cured layer, the inorganic fine particles include at least one metal oxide ultrafine particle selected from Al, Zr, Zn, Ti, In and Sn. Specific examples include ZrO ₂ , TiO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO, and the like. Among these, ZrO ₂ is particularly preferably used.

As a solvent used in the coating composition for forming each layer of 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, and to ensure liquid storage stability. Various solvents selected from the viewpoint of having an appropriate saturated vapor pressure can be used.
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 ethyl) 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 more include, for example, octane (125.7 ° C.), toluene (110.6 ° C.), xylene (138 ° C.), tetrachloroethylene (121.2 ° C.), and 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.) 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.

The easily embossable hard coat precursor layer coating composition is obtained by adding additives such as a curable composition, inorganic particles, and organic particles that form the easily embossable hard coat precursor layer to the above-described solvent.
Examples of the coating apparatus for applying the easily embossable hard coat precursor layer coating composition include an extrusion method, a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a rod coating method, and a gravure coating method. Existing application equipment can be used.

  The film thickness of the easily embossed hard coat cured layer is preferably 1 μm or more and 50 μm or less in a state where all the stepwise curing has been completed. Within this range, the embossing transfer effect is sufficiently reflected in the layer, and an excellent antiglare property can be imparted, the surface hardness is high, the curing time is short, and curling can be prevented. In this respect, the film thickness is more preferably 3 μm or more and 20 μm or less, and further preferably 4 μm or more and 12 μm or less.

  After applying the easy embossing hard coat precursor layer coating composition, the drying apparatus for drying the coating composition may be any drying system such as a convection drying system using hot air or a radiation drying system using radiant heat such as infrared rays. Well, as a film transport system in the drying apparatus, any of a contact transport system such as roller transport or a non-contact system in which the film is transported while being floated by air or gas may be used.

After applying and drying the coating composition, the active energy ray used for precuring the easily embossable hard coat precursor layer is appropriately selected according to the type of the curable composition to be used.
The surface elastic modulus of the easily embossable hard coat precursor layer before pressing is preferably less than 4.5 GPa, more preferably less than 4.0 GPa and 2.0 GPa or more. This range is preferable in that embossing can be easily performed and holes can be prevented from being generated by embossing. Furthermore, it is preferable that the easily embossed hard coat precursor layer is cured after embossing to have a surface elasticity of 4.5 Gpa or more. Below 4.5 Gpa, there are problems such as insufficient pencil hardness.

[Configuration of antireflection film]
In the present invention, an antireflection layer comprising at least one layer is coated on the easily embossed hard coat precursor layer. As the antireflection layer, a known single layer of a low refractive index layer, a two-layer antireflection layer comprising a high refractive index layer and a low refractive index layer, a middle refractive index layer, a high refractive index layer and a low refractive index layer, A three-layered antireflection layer comprising a plurality of layers, or a multilayered antireflection layer. A preferred three-layer antireflection layer will be described.
The antireflection film of the present invention has a layer structure in which an easily embossed hard coat cured layer, a medium refractive index layer, a high refractive index layer, and a low refractive index layer (outermost layer) are laminated in this order on a transparent substrate. Is preferred. The transparent substrate, the medium refractive index layer, the high refractive index layer, and the low refractive index layer have a refractive index that satisfies the following relationship.

  Refractive index of the high refractive index layer> Refractive index of the medium refractive index layer> Refractive index of the transparent substrate> Refractive index of the low refractive index layer

  In such a layer structure, 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 layer is represented by Satisfying the following mathematical formula (III) is preferable in that an antireflection film having more excellent antireflection performance can be produced.

Formula (I):
(Hλ / 4) × 0.7 <n ₃ d ₃ <(hλ / 4) × 1.3
In formula (I), h is a positive integer (generally 1, 2 or 3), n ₃ is the refractive index of the medium refractive index layer, and d ₃ is the layer thickness (nm) of the medium refractive index layer. It is. 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 <n ₄ d ₄ <(iλ / 4) × 1.3
In formula (II), i is a positive integer (generally 1, 2 or 3), n ₄ is the refractive index of the high refractive index layer, and d ₄ is the layer thickness (nm) of the high refractive index layer. It is. 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 <n ₅ d ₅ <(jλ / 4) × 1.3
In Formula (III), j is a positive odd number (generally 1), n ₅ is the refractive index of the low refractive index layer, and d ₅ 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.

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 <n ₃ d ₃ <(λ / 4) × 1.00
Formula (V):
(Λ / 2) × 0.75 <n ₄ d ₄ <(λ / 2) × 0.95
Formula (VI):
(Λ / 4) × 0.95 <n ₅ d ₅ <(λ / 4) × 1.05

[Give antiglare properties]
In this invention, after forming an antireflection layer, an unevenness | corrugation can be formed in the film surface by embossing and the glare-proof property can be provided.

FIG. 1 shows an example of a transfer device that performs embossing.
The concavo-convex shape is transferred to the surface having the antireflection layer 24 of the antireflection film 30 having the pre-cured easy embossed hard coat precursor layer 25 by the transfer device 16. After the transfer, the antiglare antireflection film 32 is cured by the curing device 17 in the irradiation chamber 80.

  As shown in FIG. 1, the transfer device 16 includes an embossing roller 34 having a large number of irregularities on a roller surface serving as a transfer surface, and a backup roller 36 disposed to face the embossing roller 34. The roll diameters of the embossing roller 34 and the backup roller 36 are preferably in the range of 100 mmφ to 800 mmφ. The backup roller 36 approaches and separates from the embossing roller 34 to adjust the clearance between the embossing roller 34 and the backup roller 36 and the press load when the antireflection film 30 is nipped between the embossing roller 34 and the backup roller 36. The The dimension of the clearance and the press load are appropriately set according to the thickness of the antireflection film 30 to be embossed, the uneven shape formed on the antireflection film 30, and other embossing conditions. A micrometer, a laser measuring instrument, etc. can be used for the actual measurement of the clearance when setting the clearance.

FIG. 2 shows a cross-sectional view of an antiglare antireflection film having irregularities transferred by embossing.
As shown in FIG. 2, the unevenness formed on the antireflection film 30 by embossing is preferably such that RSm of JIS B0601: 2001 is 5 to 30 μm, Ra is 0.01 to 1 μm, and RSm is 10 to 25 μm. , Ra is more preferably 0.015 to 0.5 μm.
Accordingly, the unevenness formed on the roll surface of the embossing roller 34 shown in FIG. 1 varies depending on the antiglare antireflection film 32 as a product, but when viewed from the transfer accuracy, the RSm of the plate JIS B0601: 2001 is 5 It is preferably 60 μm and Ra is 0.01 to 2.0 μm, more preferably RSm is 7 to 25 μm and Ra is 0.02 to 1.0 μm. Further, since the size of the unevenness transferred by the elasticity of the transparent base material 20 after transfer is somewhat reduced, the unevenness RSm and Ra of the embossing roller 34 to be used is applied to the antireflection film 30 according to the material of the transparent base material 20. It is preferable to use one that is 0% to 100% larger than the target RSm and Ra to be transferred. In this case, the unevenness due to the embossing of the easily embossable hard coat precursor layer 25 may appear on the opposite surface (the surface on the transparent base material 20 side) of the easily embossable hard coat precursor layer 25, but the embossed hard coat precursor layer 25 was embossed. The back surface of the subsequent antireflection film 30 may not be completely flat.
Further, the shape of the convex portion 34A formed on the roll surface of the embossing roller 34 is preferably a part of a spheroid. As a method for forming irregularities on the roller surface of the embossing roller 34, various known methods such as photolithography, machining, electric discharge machining, and laser processing can be employed depending on the material of the embossing roller and the shape of the irregularities.

The longitudinal elastic modulus of the embossing roller 34 is preferably 9.8 × 10 ⁶ N / cm ² or more, and more preferably 2.0 × 10 ⁷ N / cm ² or more. As the material of the embossing roller 34, steel such as S45C or a hard chrome plated material can be used.
As the backup roller 36, a roller whose longitudinal elastic modulus or hardness is smaller than that of the embossing roller 34 is used. That is, the longitudinal elastic modulus of the backup roller 36 is preferably specified to be 9.8 × 10 ⁴ N / cm ² or more and less than 9.8 × 10 ⁶ N / cm ² , more preferably 9.8 × 10 6. ^It is specified as ⁴ N / cm ² or more and 1.5 × 10 ⁶ N / cm ² or less. Any roller material can be used as long as it satisfies the conditions of longitudinal elastic modulus and hardness, but a plastic roller, particularly a polyamide resin (commonly known as MC nylon) or polyacetal resin that has been subjected to a hard treatment, is preferably used. Can do.

As described above, when the longitudinal elastic modulus and pencil hardness of the backup roller 36 are made smaller than the longitudinal elastic modulus and pencil hardness of the embossing roller 34, the antireflection film 30 is nipped between the embossing roller 34 and the backup roller 36. When the unevenness is imparted to the surface of the antireflection layer 24, it is preferable in that the backup roller 36 can disperse the pressure by which the convex portion 34 </ b> A of the embossing roller 34 presses the backup roller 36 through the antireflection film 30. By this pressure dispersion, it is possible to prevent the convex portion 34 </ b> A of the embossing roller 34 from penetrating the antireflection film 30 and opening a hole in the antireflection film 30. Further, if the longitudinal elastic modulus and hardness of the backup roller 36 are too small, the transfer accuracy is deteriorated. However, by setting the lower limit of the longitudinal elastic modulus to 9.8 × 10 ⁴ N / cm ² , the transfer accuracy is adversely affected. Nor.

  As other conditions in this transfer operation, the press pressure (linear pressure) for nipping the antireflection film 30 between the embossing roller 34 and the backup roller 36 is preferably 1000 N / cm to 30000 N / cm, more preferably 5000 N / cm. ~ 15000 N / cm. Therefore, the clearance between the embossing roller 34 and the backup roller 36 and the pressing load may be adjusted according to the thickness of the antireflection film 30 so as to obtain this pressing pressure. In this case, it is preferable to provide a load measuring device such as a load cell to measure the press load, grasp the relationship between the press load and the perforation of the antireflection film 30 and the transfer accuracy, and adjust the clearance and the press load based on the relationship. The transfer processing speed is preferably in the range of 0.1 m / min to 50 m / min, and more preferably in the range of 1 m / min to 20 m / min.

  Moreover, it is preferable to emboss the antireflection film 30 in a state where the roller surface temperatures of the embossing roller 34 and the backup roller 36 are heated. The upper limit of the roller surface temperature of the embossing roller 34 and the backup roller 36 is preferably equal to or lower than the glass transition temperature of the transparent substrate 20 to be used. Above the glass transition temperature, the substrate may be stretched or deformed due to heat shrinkage, which may make handling difficult. Therefore, treatment at a glass transition temperature or lower is preferable. As a heating means for obtaining such a temperature condition, although not particularly illustrated, for example, a water passage pipe is incorporated in each of the embossing roller 34 and the backup roller 36, and the water passage pipe is respectively connected via a rotary joint. And connected to a heat medium supply device. Then, the roller surface temperature of the embossing roller 34 and the backup roller 36 is heated by circulating a heat medium such as hot water between the rollers. The heating means is not limited to the medium circulation method, and induction heating or other heating methods can be used.

  In the present embodiment, the transfer device 16 has been described as a continuous method in which the embossing is performed by continuously flowing the strip-shaped antireflection film 30 through the embossing roller 34 and the backup roller 36, but the single-leaf antireflection film 30 is used. A batch system in which the sheet is nipped between the embossing roller 34 and the backup roller 36 one by one may be used. In the case of this batch system, instead of the embossing roller 34 and the backup roller 36, a plate mold 70 having a large number of irregularities formed on the transfer surface as shown in FIG. It is also possible to use a configuration in which a flat support member 72 having the same longitudinal elastic modulus and hardness as the backup roller 36 described above is disposed on the support base 74 and the single-leaf antireflection film 30 is pressed by the plate 70 and the support member 72.

[Transparent substrate]
The transparent substrate is preferably a plastic film. Examples of the plastic film include cellulose acylate (for example, cellulose triacetate, cellulose diacetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose propionate, nitrocellulose, etc.), polyolefin (for example, polypropylene, polyethylene, polymethylpentene). Are included). Among these, triacetylcellulose and polyolefin are preferable for polarizing plates because of their low retardation and high optical uniformity. In particular, when used in a liquid crystal display device, it is preferable to use cellulose triacetate.

Plastic film (transparent substrate) has various additives depending on various purposes (for example, UV absorber, release agent, antistatic agent, deterioration preventing agent (for example, antioxidant, peroxide decomposer, radical inhibitor, Metal deactivators, acid scavengers, amines) and infrared absorbers, etc.) may be solid or oily. Moreover, when a film is formed from a multilayer, the kind and addition amount of the additive of each layer may differ. For these details, materials described in detail on pages 16 to 22 of the technique No. 2001-1745 are preferably used.
It is preferable to use the above-mentioned cellulose triacetate for the transparent substrate of the present invention. Examples of ultraviolet absorbers preferably used for cellulose triacetate include benzophenone compounds, oxybenzophenone compounds, benzotriazole compounds, salicylate compounds, cyanoacrylate compounds, nickel complex compounds, and the like in the present invention. Is preferably substantially free of a benzotriazole skeleton ultraviolet absorber from the viewpoint of preventing yellowing during electron beam irradiation. Here, “substantially not contained” means that the content of the ultraviolet absorber having a benzotriazole skeleton is 0.1% by mass or less based on cellulose triacetate.

[Antireflection layer]
<High (medium) refractive index layer>
The antireflection layer of the present invention may be a single layer or a multilayer structure, but it is preferable that the low refractive index layer, the high refractive index layer, and the middle refractive index layer are laminated in this order from the outermost surface. In the present invention, the refractive index of the high refractive index layer is preferably 1.65 to 2.40, more preferably 1.70 to 2.20. The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.55 to 1.80. The haze of the high refractive index layer and the medium refractive index layer is preferably 3% or less.

  In the high refractive index layer and the middle refractive index layer of the present invention, inorganic fine particles having a high refractive index are organically substituted with a binder precursor such as a polyfunctional monomer described below, an initiator, and a general formula [A]. A cured product of a cured composition dispersed in a silicon compound is preferably used. As the inorganic fine particles, metal (eg, aluminum, titanium, zirconium, antimony) oxides are preferable, and from the viewpoint of refractive index, titanium dioxide fine particles are most preferable. When using a monomer and an initiator in a coating composition for forming a high refractive index layer or a medium refractive index layer, the medium refractive index is excellent in scratch resistance and adhesion by curing the monomer by ionizing radiation or heat polymerization after coating. A refractive index layer and a high refractive index layer can be formed. The average particle size of the inorganic fine particles is preferably 10 to 100 nm.

As the titanium dioxide fine particles, inorganic fine particles containing titanium dioxide as a main component and containing at least one element selected from cobalt, aluminum, and zirconium are particularly preferable. The main component means a component having the largest content (mass%) among the components constituting the particles.
The inorganic fine particles mainly composed of titanium dioxide in the present invention preferably have a refractive index of 1.90 to 2.80, more preferably 2.10 to 2.80, and 2.20 to 2.80. 80 is most preferred.
The mass average diameter of primary particles of inorganic fine particles mainly composed of titanium dioxide is preferably 1 to 200 nm, more preferably 5 to 150 nm, still more preferably 10 to 100 nm, and particularly preferably 10 to 80 nm.

The particle diameter of the inorganic fine particles can be measured by a light scattering method or an electron micrograph. The specific surface area of the inorganic fine particles is preferably 10 to 400 m ² / g, more preferably from 20 to 200 m ² / g, and most preferably from 30 to 150 m ² / g.
The crystal structure of the inorganic fine particles containing titanium dioxide as a main component is preferably a rutile, rutile / anatase mixed crystal, anatase or amorphous structure, particularly preferably a rutile structure. The main component means a component having the largest content (mass%) among the components constituting the particles.

By containing at least one element selected from Co (cobalt), Al (aluminum) and Zr (zirconium) in the inorganic fine particles mainly composed of titanium dioxide, the photocatalytic activity of titanium dioxide can be suppressed, The weather resistance of the high refractive index layer and the medium refractive index layer of the present invention can be improved.
A particularly preferable element is Co (cobalt). It is also preferable to use two or more types in combination.

[Dispersant]
A dispersant can be used for dispersing inorganic fine particles mainly composed of titanium dioxide used in the high refractive index layer and the medium refractive index layer of the present invention.
In order to disperse the inorganic fine particles mainly composed of titanium dioxide of the present invention, it is particularly preferable to use a dispersant having an anionic group.
As the anionic group, a group having an acidic proton such as a carboxyl group, a sulfonic acid group (and a sulfo group), a phosphoric acid group (and a phosphono group), or a sulfonamide group, or a salt thereof is effective. A sulfonic acid group, a phosphoric acid group and a salt thereof are preferable, and a carboxyl group and a phosphoric acid group are particularly preferable. The number of anionic groups contained in the dispersant per molecule may be one or more.
A plurality of anionic groups may be contained for the purpose of further improving the dispersibility of the inorganic fine particles. The average number is preferably 2 or more, more preferably 5 or more, and particularly preferably 10 or more. Moreover, the anionic group contained in a dispersing agent may contain multiple types in 1 molecule.

The dispersant preferably further contains a crosslinkable or polymerizable functional group. Examples of the crosslinkable or polymerizable functional group include ethylenically unsaturated groups (for example, (meth) acryloyl group, allyl group, styryl group, vinyloxy group, etc.) capable of addition reaction / polymerization reaction by radical species, cationic polymerizable group (epoxy) Groups, oxatanyl groups, vinyloxy groups, etc.), polycondensation reactive groups (hydrolyzable silyl groups, etc., N-methylol groups), and the like. Preferred are functional groups having an ethylenically unsaturated group.
A preferred dispersant used for dispersion of inorganic fine particles mainly composed of titanium dioxide used in the high refractive index layer of the present invention has an anionic group and a crosslinkable or polymerizable functional group, and the crosslinkable or polymerizable functional group. In the side chain.
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 mass average molecular weight (Mw) of the dispersant is 2000 to 1000000, more preferably 5000 to 200000, and particularly preferably 10000 to 100000.

  The amount of the dispersant used relative to the inorganic fine 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.

[Dispersion of inorganic fine particles]
The inorganic fine particles mainly composed of titanium dioxide used for the high refractive index layer and the medium refractive index layer are used for forming the high refractive index layer and the medium refractive index layer in the state of dispersion.
In the dispersion of the inorganic fine particles, it is dispersed in a dispersion medium in the presence of the dispersant.
As the dispersion medium, a liquid having a boiling point of 60 to 170 ° C. is preferably used. Examples of dispersion media include water, alcohol (eg, methanol, ethanol, isopropanol, butanol, benzyl alcohol), ketone (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), ester (eg, methyl acetate, ethyl acetate, Propyl acetate, butyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate), aliphatic hydrocarbons (eg, hexane, cyclohexane), halogenated hydrocarbons (eg, methylene chloride, chloroform, carbon tetrachloride), aromatic Hydrocarbon (eg, benzene, toluene, xylene), amide (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone), ether (eg, diethyl ether, dioxane, tetrahydrofuran), ether alcohol (eg, 1-methyl) Carboxymethyl-2-propanol) are included. Toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol are preferred.
Particularly preferred dispersion media are methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

The inorganic fine particles are dispersed using a disperser. Examples of dispersers include sand grinder mills (eg, pin bead mills), high speed impeller mills, pebble mills, roller mills, attritors and colloid mills. 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 have a mass average diameter of 1 to 200 nm. Preferably it is 5-150 nm, More preferably, it is 10-100 nm, Most preferably, it is 10-80 nm.
By refining the inorganic fine particles to 200 nm or less, a high refractive index layer and a medium refractive index layer that do not impair transparency can be formed.

<Method for forming high (medium) refractive index layer>
The high refractive index layer and medium refractive index layer used in the present invention are preferably a binder precursor (for example, described later) required for forming a matrix in a dispersion liquid in which inorganic fine particles are dispersed in a dispersion medium as described above. Ionizing radiation curable polyfunctional monomers and polyfunctional oligomers), photopolymerization initiators, etc. are added to form a coating composition for forming a high refractive index layer and a medium refractive index layer. It is preferably formed by applying a coating composition for forming a medium refractive index layer and curing it by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound (for example, a polyfunctional monomer or a polyfunctional oligomer).

Furthermore, it is preferable to cause the binder of the high refractive index layer and the medium refractive index layer to undergo a crosslinking reaction or a polymerization reaction with the dispersant simultaneously with or after the coating of the layer.
The binder of the high refractive index layer and the medium refractive index layer produced in this way is, for example, the above-mentioned preferred dispersant and ionizing radiation curable polyfunctional monomer or polyfunctional oligomer are crosslinked or polymerized to form a binder. The anionic group of the dispersant is incorporated. Furthermore, in the binder of the high refractive index layer and the medium refractive index layer, the anionic group contained in the dispersant has a function of maintaining the dispersed state of the inorganic fine particles, and the crosslinked or polymerized structure imparts a film forming ability to the binder. Therefore, this can improve the physical strength, chemical resistance, and weather resistance of the high refractive index layer and the middle refractive index layer.

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.
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. Among them, 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, 2-2-2bis {4- (acryloxy-polypropoxy) phenyl} propane ;
Etc.

  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, dipentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol triacrylate, tripentaerythritol hexatriacrylate, etc. Is mentioned.
Two or more polyfunctional monomers may be used in combination.

It is preferable to use a photopolymerization initiator for the polymerization reaction of the 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.
Examples of the radical photopolymerization initiator include acetophenones, benzophenones, Michler's benzoylbenzoate, α-amyloxime ester, tetramethylthiuram monosulfide, and thioxanthones.

  Commercially available radical photopolymerization initiators include KAYACURE (DETX-S, BP-100, BDDK, CTX, BMS, 2-EAQ, ABQ, CPTX, EPD, ITX, QTX, BTC, manufactured by Nippon Kayaku Co., Ltd. MCA, etc.), Irgacure (651, 184, 500, 907, 369, 1173, 2959, 4265, 4263, etc.) manufactured by Ciba Geigy Japan, Ltd., Esacure (KIP100F, KB1, EB3, BP, X33, KT046) manufactured by Sartomer , KT37, KIP150, TZT) and the like.

In particular, photocleavable photoradical polymerization initiators are preferred. The photocleavable photoradical polymerization initiator is described in the latest UV curing technology (p.159, issuer; Kazuhiro Takashiro, publisher; Technical Information Association, published in 1991).
Examples of commercially available photocleavable photoradical polymerization initiators include Irgacure (651, 184, 907) manufactured by Ciba Geigy Japan.

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.
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.
Examples of commercially available photosensitizers include KAYACURE (DMBI, EPA) manufactured by Nippon Kayaku Co., Ltd.
The photopolymerization reaction is preferably performed by ultraviolet irradiation after the high refractive index layer is applied and dried.

The high refractive index layer used in the present invention further contains an organosilane compound represented by the general formula [A] and / or a hydrolyzate thereof and / or a partial condensate thereof (hereinafter referred to as a sol component). You can also.
Formula _{^{[A] (R 10) m}} -Si (X) 4-m

In the above general formula [A], R ¹⁰ is a substituted or unsubstituted alkyl group (a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, heptyl, etc. , Octyl, decyl, dodecyl, isopropyl, s-butyl, t-amyl, cyclohexyl, cyclopentyl), a substituted or unsubstituted aryl group (an aryl group having 6 to 20 carbon atoms, for example, phenyl, 1-naphthyl). .
X represents a hydrolyzable group, for example, an alkoxy group (an alkoxy group having 1 to 5 carbon atoms, such as methoxy, ethoxy), halogen (for example, Cl, Br, I, etc.), or R ² COO (R ² is A hydrogen atom or an alkyl group having 1 to 5 carbon atoms is preferable, and examples thereof include CH ₃ COO and C ₂ H ₅ COO. X is preferably an alkoxy group, particularly preferably a methoxy group or an ethoxy group.
m represents an integer of 1 to 3. When R ¹⁰ or X there are a plurality, a plurality of R ¹⁰ or X may be different even in the same, respectively. m is preferably 1 or 2, particularly preferably 1.

The substituent contained in R ¹⁰ is not particularly limited, but is halogen (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 (such as methylthio, ethylthio), arylthio groups (such as phenylthio), alkenyl groups (such as vinyl and 1-propenyl), acyloxy groups (such as acetoxy, acryloyloxy, methacryloyloxy), alkoxycarbonyl groups (methoxycarbonyl, ethoxycarbonyl) Etc.), aryloxyca Bonyl group (such as phenoxycarbonyl), carbamoyl group (such as carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N-methyl-N-octylcarbamoyl), acylamino group (acetylamino, benzoylamino, acrylicamino, methacrylamino) Etc.), and these substituents may be further substituted.

  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 1.65 to 2.40. More preferably, it is 70 to 2.20.

  In addition to the above-mentioned components (inorganic fine particles, polymerization initiators, photosensitizers, etc.), the high (medium) refractive index layer contains resins, surfactants, antistatic agents, coupling agents, thickeners, and coloring prevention. Agents, colorants (pigments, dyes), antifoaming agents, leveling agents, flame retardants, UV absorbers, infrared absorbers, adhesion promoters, polymerization inhibitors, antioxidants, surface modifiers, conductive metal fine particles , Etc. can also be added.

In the formation of the high (medium) refractive index layer, the crosslinking reaction or polymerization reaction of the ionizing radiation curable compound is preferably carried out in an atmosphere having an oxygen concentration of 10% by volume or less.
By forming the high (medium) refractive index layer in an atmosphere having an oxygen concentration of 10% by volume or less, the physical strength, chemical resistance and weather resistance of the high (medium) refractive index layer, and also the high (medium) refractive index The adhesion between the layer, the high (medium) refractive index layer and the adjacent layer can be improved.
Preferably, it is formed by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound in an atmosphere having an oxygen concentration of 6% by volume or less, more preferably an oxygen concentration of 4% by volume or less, particularly preferably an oxygen concentration of 2% by volume. Hereinafter, it is most preferably 1% by volume or less.

<Low refractive index layer>
The low refractive index layer is preferably formed by a cured film of a copolymer having a repeating unit derived from a fluorine-containing vinyl monomer and a repeating unit having a (meth) acryloyl group in the side chain as essential constituent components. The copolymer-derived component preferably occupies 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 80% by mass or more. From the viewpoint of achieving both low refractive index and film hardness, a curing agent such as polyfunctional (meth) acrylate is also preferably used in an addition amount within a range that does not impair the compatibility.

The refractive index of the low refractive index layer is preferably 1.20 to 1.49, more preferably 1.25 to 1.48, and particularly preferably 1.30 to 1.46.
The thickness of the low refractive index layer is preferably 50 to 200 nm, and more preferably 70 to 100 nm. The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, and most preferably 1% or less. The specific strength of the low refractive index layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test under a 500 g load.
Further, in order to improve the antifouling performance of the antireflection film, it is preferable that the contact angle of the surface with respect to water is 90 ° or more. More preferably, it is 95 ° or more, and particularly preferably 100 ° or more.

The copolymer used for the low-refractive-index layer of this invention is demonstrated below.
Examples of the fluorine-containing vinyl monomer include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, etc.), (meth) acrylic acid moieties or fully fluorinated alkyl ester derivatives (for example, biscoat 6FM (trade name) , Osaka Organic Chemical Co., Ltd.), M-2020 (trade name, manufactured by Daikin Co., Ltd.), fully or partially fluorinated vinyl ethers, and the like. Preferred are perfluoroolefins, refractive index, solubility, and transparency. From the viewpoint of availability, hexafluoropropylene is particularly preferable. Increasing the composition ratio of these fluorinated vinyl monomers can lower the refractive index but lowers the film strength. In the present invention, the fluorine-containing vinyl monomer is preferably introduced so that the fluorine content of the copolymer is 20 to 60% by mass, more preferably 25 to 55% by mass, and particularly preferably 30 to 50%. This is a case of mass%.

  The copolymer of the present invention preferably has a repeating unit having a (meth) acryloyl group in the side chain as an essential component. If the composition ratio of these (meth) acryloyl group-containing repeating units is increased, the film strength is improved, but the refractive index is also increased. Generally, the (meth) acryloyl group-containing repeating unit preferably accounts for 5 to 90% by mass, more preferably 30 to 70% by mass, although it varies depending on the type of repeating unit derived from the fluorine-containing vinyl monomer. It is particularly preferred to account for ~ 60% by weight.

  In the copolymer useful for the present invention, in addition to the repeating unit derived from the above-mentioned fluorine-containing vinyl monomer and the repeating unit having a (meth) acryloyl group in the side chain, it contributes to adhesion to the substrate and Tg of the polymer (film hardness). And other vinyl monomers can be copolymerized as appropriate from various viewpoints such as solubility in a solvent, transparency, slipperiness, dust resistance and antifouling properties. A plurality of these vinyl monomers may be combined depending on the purpose, and are preferably introduced in the range of 0 to 65 mol% in the copolymer in total, and more preferably in the range of 0 to 40 mol%. Is particularly preferably in the range of 0 to 30 mol%.

  The vinyl monomer unit that can be used in combination is not particularly limited. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, acrylic acid) 2-ethylhexyl, 2-hydroxyethyl acrylate), methacrylic acid esters (methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-hydroxyethyl methacrylate, etc.), styrene derivatives (styrene, p-hydroxymethylstyrene, p -Methoxystyrene, etc.), vinyl ethers (methyl vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, etc.), vinyl esters (vinyl acetate) Vinyl propionate, vinyl cinnamate, etc.), unsaturated carboxylic acids (acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, etc.), acrylamides (N, N-dimethylacrylamide, N-tertbutylacrylamide, N- Cyclohexyl acrylamide, etc.), methacrylamides (N, N-dimethylmethacrylamide), acrylonitrile and the like.

  As a preferred form of the copolymer used in the present invention, one having the following general formula 1 can be mentioned.

In General Formula 1, L represents a linking group having 1 to 10 carbon atoms, more preferably a linking group having 1 to 6 carbon atoms, particularly preferably a linking group having 2 to 4 carbon atoms, It may have a branched structure, may have a ring structure, and may have a heteroatom selected from O, N, and S.
Preferred _{examples, * - (CH 2) 2} -O - **, * - (CH 2) 2 -NH - **, * - (CH 2) 4 -O - **, * - (CH 2) ₆ −O − **, * − (CH ₂ ) ₂ −O− (CH ₂ ) ₂ −O − **, −CONH− (CH ₂ ) ₃ −O − **, * −CH ₂ CH (OH) CH ₂ —O— *, * —CH ₂ CH ₂ OCONH (CH ₂ ) ₃ —O — ** (* represents a connecting site on the polymer main chain side, and ** represents a connecting site on the (meth) acryloyl group side) And the like). m represents 0 or 1;

  In general formula 1, X represents a hydrogen atom or a methyl group. From the viewpoint of curing reactivity, a hydrogen atom is more preferable.

  In the general formula 1, A represents a repeating unit derived from an arbitrary vinyl monomer, and is not particularly limited as long as it is a constituent component of a monomer copolymerizable with hexafluoropropylene. Tg (contributes to film hardness), solubility in solvents, transparency, slipperiness, dust / antifouling properties, etc., can be selected as appropriate, depending on the purpose, depending on the single or multiple vinyl monomers It may be configured.

  In the general formula 1, preferred examples of A include methyl vinyl ether, ethyl vinyl ether, t-butyl vinyl ether, cyclohexyl vinyl ether, isopropyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, vinyl ethers such as glycidyl vinyl ether, allyl vinyl ether, acetic acid, and the like. Vinyl esters such as vinyl, vinyl propionate, vinyl butyrate, methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, glycidyl methacrylate, allyl (meth) acrylate, (meth) acryloyloxypropyltri (Meth) acrylates such as methoxysilane, styrene, styrene derivatives such as p-hydroxymethylstyrene, crotonic acid, male Acid, can be mentioned and unsaturated carboxylic acids and derivatives thereof such as itaconic acid, more preferably a vinyl ether derivative, vinyl ester derivatives, particularly preferably a vinyl ether derivative.

  x, y, and z represent mol% of each constituent component, and represent values satisfying 30 ≦ x ≦ 60, 5 ≦ y ≦ 70, and 0 ≦ z ≦ 65. Preferably, 35 ≦ x ≦ 55, 30 ≦ y ≦ 60, and 0 ≦ z ≦ 20, and particularly preferably 40 ≦ x ≦ 55, 40 ≦ y ≦ 55, and 0 ≦ z ≦ 10.

A particularly preferred form of the copolymer used in the present invention is General Formula 2.

In the general formula 2, X, x, and y have the same meaning as in the general formula 1, and preferred ranges are also the same.
n represents an integer of 2 ≦ n ≦ 10, preferably 2 ≦ n ≦ 6, and particularly preferably 2 ≦ n ≦ 4.
B represents a unit of a repeating unit derived from an arbitrary vinyl monomer, and may be composed of a single composition or a plurality of compositions. As an example, what was demonstrated as an example of A in the said General formula 1 is applicable.
Z1 and Z2 represent mol% of each repeating unit, and represent values satisfying 0 ≦ z1 ≦ 65 and 0 ≦ z2 ≦ 65. It is preferable that 0 ≦ z1 ≦ 30 and 0 ≦ z2 ≦ 10 respectively, and it is particularly preferable that 0 ≦ z1 ≦ 10 and 0 ≦ z2 ≦ 5.

  The copolymer represented by the general formula 1 or the general formula 2 can be synthesized, for example, by introducing a (meth) acryloyl group into a copolymer containing a hexafluoropropylene component and a hydroxyalkyl vinyl ether component. A method for synthesizing the copolymers represented by the general formulas 1 and 2 of the present invention is described in detail in JP-A-2004-045462.

  Although the preferable example of the copolymer useful by this invention is shown below, this invention is not limited to these.

  The low refractive index layer coating liquid composition in the present invention is usually in the form of a liquid, and the copolymer is an essential constituent, and various additives and a radical polymerization initiator are dissolved in an appropriate solvent as necessary. Produced. At this time, the concentration of the solid content is appropriately selected according to the use, but is generally about 0.01 to 60% by mass, preferably 0.5 to 50% by mass, particularly preferably 1% to 20% by mass. %.

  As described above, it is not always advantageous to add an additive such as a curing agent from the viewpoint of film hardness of the low refractive index layer, but from the viewpoint of interfacial adhesion with the high refractive index layer, etc. ) A curing agent such as an acrylate compound, polyfunctional epoxy compound, polyisocyanate compound, aminoplast, polybasic acid or anhydride thereof, or a small amount of inorganic fine particles such as silica can be added. When adding these, it is preferable that it is the range of 0-30 mass% with respect to the total solid of a low refractive index layer membrane | film | coat, It is more preferable that it is the range of 0-20 mass%, 0-10 mass % Range is particularly preferred.

  In addition, for the purpose of imparting properties such as antifouling properties, water resistance, chemical resistance, and slipping properties, known silicone-based or fluorine-based antifouling agents, slipping agents, and the like can be appropriately added. When these additives are added, it is preferably added in the range of 0 to 20% by mass of the total solid content of the low refractive index layer, and more preferably in the range of 0 to 10% by mass. Particularly preferred is 0 to 5% by mass.

  The radical polymerization initiator may be in any form of generating radicals by the action of heat or generating radicals by the action of light.

As the compound that initiates radical polymerization by the action of heat, organic or inorganic peroxides, organic azo, diazo compounds, and the like can be used.
Specifically, benzoyl peroxide, halogen benzoyl peroxide, lauroyl peroxide, acetyl peroxide, dibutyl peroxide, cumene hydroperoxide, butyl hydroperoxide as organic peroxides, hydrogen peroxide, peroxides as inorganic peroxides. Ammonium sulfate, potassium persulfate, etc., 2-azo-bis-isobutyronitrile, 2-azo-bis-propionitrile, 2-azo-bis-cyclohexanedinitrile, etc., diazoaminobenzene, p-nitrobenzene, etc. as organic diazo compounds And diazonium.

When a compound that initiates radical polymerization by the action of light is used, the coating is cured by irradiation with active energy rays.
Examples of such radical photopolymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds , Disulfide compounds, fluoroamine compounds and aromatic sulfoniums. Examples of acetophenones include 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone and 2 -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone is included. Examples of benzoins include benzoin benzene sulfonate, benzoin toluene sulfonate, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether. Examples of the benzophenones include benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone. Examples of phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide. Sensitizing dyes can also be preferably used in combination with these photoradical polymerization initiators.

  The amount of the compound that initiates radical polymerization by the action of heat or light may be any amount that can initiate the polymerization of the carbon-carbon double bond, but generally the total amount in the low refractive index layer forming composition is not limited. 0.1-15 mass% is preferable with respect to solid content, More preferably, it is 0.5-10 mass%, Most preferably, it is a case of 2-5 mass%.

  The solvent contained in the low refractive index layer coating liquid composition is not particularly limited as long as the composition containing the fluorine-containing copolymer is uniformly dissolved or dispersed without causing precipitation. A solvent can also be used in combination. Preferred examples include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), esters (ethyl acetate, butyl acetate, etc.), ethers (tetrahydrofuran, 1,4-dioxane, etc.), alcohols (methanol, ethanol, isopropyl). Alcohol, butanol, ethylene glycol, etc.), aromatic hydrocarbons (toluene, xylene, etc.), water and the like.

  The low refractive index layer may contain a filler (for example, inorganic fine particles and organic fine particles), a silane coupling agent, a slip agent (silicone compound such as dimethyl silicone), a surfactant, etc. in addition to the fluorine-containing compound. it can. In particular, it is preferable to contain inorganic fine particles, a silane coupling agent, and a slip agent.

  As the inorganic fine particles, silicon dioxide (silica), fluorine-containing particles (magnesium fluoride, calcium fluoride, barium fluoride) and the like are preferable. Particularly preferred is silicon dioxide (silica). The mass average diameter of primary particles of the inorganic fine particles is preferably 1 to 150 nm, more preferably 1 to 100 nm, and most preferably 1 to 80 nm. It is preferable that the inorganic fine particles are more finely dispersed in the outermost layer. The shape of the inorganic fine particles is preferably a rice grain shape, a spherical shape, a cubic shape, a spindle shape, a short fiber shape, a ring shape, or an indefinite shape.

  As the silane coupling agent, a compound represented by the general formula A and / or a derivative compound thereof can be used. Preferred are silane coupling agents containing a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, an alkoxysilyl group, an acyloxy group, and an acylamino group, and particularly preferred are an epoxy group and a polymerizable acyloxy group ( (Meth) acryloyl), a silane coupling agent containing a polymerizable acylamino group (acrylamino, methacrylamino).

Particularly preferred among the compounds represented by formula A are compounds having a (meth) acryloyl group as a crosslinkable or polymerizable functional group, such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxy. Silane etc. are mentioned.
As the slip agent, dimethyl silicone and a fluorine-containing compound into which a polysiloxane segment is introduced are preferable.

The low refractive index layer is a coating reaction in which a fluorine-containing compound or other optional components contained or dissolved as desired is dissolved or dispersed simultaneously with coating, or after coating, by light irradiation, electron beam irradiation or heating, It is preferably formed by a polymerization reaction.
In particular, when the low refractive index layer is formed by a crosslinking reaction or polymerization reaction of an ionizing radiation curable compound, the crosslinking reaction or polymerization reaction is preferably performed in an atmosphere having an oxygen concentration of 10% by volume or less. By forming in an atmosphere having an oxygen concentration of 10% by volume or less, an outermost layer having excellent physical strength and chemical resistance can be obtained.
The oxygen concentration is preferably 6% by volume or less, more preferably 4% by volume or less, particularly preferably 2% by volume or less, and most preferably 1% by volume or less.

  As a method of reducing the oxygen concentration to 10% by volume or less, it is preferable to replace the atmosphere (nitrogen concentration of about 79% by volume, oxygen concentration of about 21% by volume) with another gas, particularly preferably replacement with nitrogen (nitrogen purge). It is to be.

[Other layers of antireflection film]
As described above, in order to produce an antireflection film having better antireflection performance, an intermediate refractive index layer having a refractive index between the refractive index of the high refractive index layer and the refractive index of the transparent substrate is provided. Is preferred.
The medium refractive index layer is preferably produced in the same manner as described in the high refractive index layer of the present invention, and the refractive index can be adjusted by controlling the content of the inorganic fine particles in the film.
The antireflection film may be provided with layers other than those described above. For example, an adhesive layer, a shield layer, a sliding layer, or an antistatic layer may be provided. The shield layer is provided to shield electromagnetic waves and infrared rays.
Further, the antireflection film may be provided with a hard coat layer having a higher hardness than the hard embossed hard coat cured layer. Thereby, it is easy to give an unevenness | corrugation to an antireflection layer, and it is possible to raise the pencil hardness of an antireflection film.

  In addition, when an antireflection film is applied to a liquid crystal display device, for the purpose of improving viewing angle characteristics, an undercoat layer to which particles having an average particle diameter of 0.1 to 10 μm are added is newly constructed or easily embossed. The said particle | grain can be added in a hard-coat hardened layer, and it can be set as a light-scattering easily embossable hard-coat hardened layer. The average particle diameter of the particles is preferably 0.2 to 5.0 μm, more preferably 0.3 to 4.0 μm, and particularly preferably 0.5 to 3.5 μm.

The refractive index of the particles is preferably 1.35 to 1.80, more preferably 1.40 to 1.75, and still more preferably 1.45 to 1.75.
The narrower the particle size distribution, the better. The S value indicating the particle size distribution of the particles is represented by the following formula, preferably 1.5 or less, more preferably 1.0 or less, and particularly preferably 0.7 or less.
S = [D (0.9) −D (0.1)] / D (0.5)
D (0.1): Particle size equivalent to 10% of the integrated value of the volume converted particle size D (0.5): Particle size equivalent to 50% of the integrated value of the volume converted particle size D (0.9): Volume converted particle Diameter equivalent to 90% of the integrated diameter

The difference in refractive index between the refractive index of the particles and the refractive index of the undercoat layer is preferably 0.02 or more. More preferably, the difference in refractive index is 0.03 to 0.5, more preferably the difference in refractive index is 0.05 to 0.4, and particularly preferably the difference in refractive index is 0.07 to 0.3. .
As the particles to be added to the undercoat layer, various inorganic particles or organic particles satisfying the above refractive index can be used. Organic particles include polymethyl methacrylate beads (refractive index 1.49), acrylic-styrene copolymer beads (refractive index 1.54), melamine beads (refractive index 1.57), polycarbonate beads (refractive index 1.57). ), Styrene beads (refractive index 1.60), cross-linked polystyrene beads (refractive index 1.61), polyvinyl chloride beads (refractive index 1.60), benzoguanamine-melamine formaldehyde beads (refractive index 1.68), etc. It is done.
As the inorganic particles, silica beads (refractive index 1.44), alumina beads (refractive index 1.63), and the like are used.
The undercoat layer is preferably constructed between the easily embossed hard coat cured layer and the transparent substrate. Moreover, it can also be set as a light-scattering easily embossable hard-coat hardened layer also serving as an easily embossable hard-coat hardened layer.
When particles having an average particle diameter of 0.1 to 10 μm are added to the undercoat layer, the haze of the undercoat layer is preferably 3 to 60%. More preferably, it is 5 to 50%, further preferably 7 to 45%, particularly preferably 10 to 40%.

[Antireflection film formation method, etc.]
Each layer of the antireflection film can be formed by a coating method such as wire bar coating, gravure coating, micro gravure, or die coating. The microgravure method and the gravure method are preferable from the viewpoint of eliminating drying unevenness by minimizing the wet coating amount, and in the coating part from the viewpoint of the film thickness uniformity in the width direction and the film thickness uniformity in the longitudinal direction over time. A forward gravure method in which a transparent substrate is nipped between a plate cylinder and an impression cylinder is particularly preferable. At least two layers of the plurality of optical thin films of the antireflection film of the present invention are formed by a process of feeding the transparent base film once, forming each optical thin film, and winding the film. It is preferable from the viewpoint of production cost, and when the antireflection layer has a three-layer structure, it is more preferable to form the three layers in one step. In such a manufacturing method, a plurality of coating stations and drying / curing zone sets, preferably the same number or more as the number of optical thin films, are arranged in series between the feeding and winding of the transparent substrate film of the coating machine. This is achieved by providing them.
FIG. 4 shows an example of the device configuration. FIG. 4 shows a first coating station (102), a first drying zone (103), and a first UV irradiator (104) during one step from roll film delivery (101) to winding (112). , Second coating station (105), second drying zone (106), second UV irradiator (107), third coating station (108), third drying zone (109), third This is an example including a UV irradiator (110) and a post-drying zone (111), for example, a medium refractive index layer, a high refractive index layer and a low refractive index layer, a hard coat layer, a high refractive index layer and a low refractive index. It is possible to form up to three functional layers and up to three functional layers in one step. If necessary, the number of coating stations is reduced to two, and only two layers, the middle refractive index layer and the high refractive index layer, are formed in one step, and the results of checking the surface shape, film thickness, etc. are fed back. As a result, the hard coat layer, medium refractive index layer, high refractive index layer, and low refractive index layer are formed in a single process, resulting in a significant reduction in coating cost. It is also mentioned as another preferable form that it is set as the manufacturing method of these.

  The arithmetic average roughness (Ra) of the outermost surface opposite to the transparent substrate surface of the antireflection film having an antiglare function of the present invention is preferably 0.05 to 0.5 μm, and 0.07. More preferably, it is -0.3 micrometer, and it is most preferable that it is 0.08-0.25 micrometer. This range is preferable in that a sufficient anti-glare function can be obtained, and the resolution can be reduced, and the image can be prevented from shining white when exposed to external light.

The reflectance of the antireflection film of the present invention is a mirror surface average reflectance of 450 to 650 nm, preferably 0.40% or less, and more preferably 0.30% or less.
The pencil hardness of the surface is a value measured by the method described in JIS K 5400, preferably H or higher, and more preferably 2H or higher.

[Protective film for polarizing plate]
In creating the polarizing plate of the present invention, in order to use the antireflection film as the surface protective film of the polarizing film (protective film for polarizing plate), the surface of the transparent substrate opposite to the side having the high refractive index layer, That is, it is essential to improve the adhesion with a polarizing film containing polyvinyl alcohol as a main component by making the surface of the side to be bonded to the polarizing film hydrophilic.

  As a method for producing a protective film for polarizing plate in the present invention, (1) each layer (eg, high refractive index layer, easily embossed hard coat cured layer, outermost layer) on one surface of a transparent substrate previously saponified. (2) Each layer described above (eg, high refractive index layer, hard embossed hard coat cured layer, low refractive index layer, outermost layer, etc.) was formed on one surface of the transparent substrate. There are two possible methods: saponification treatment on the side to be bonded to the polarizing film, but (1) is hydrophilic to the surface on which the hard embossed hard coat layer is to be formed. The method (2) is preferred because it is difficult to ensure adhesion with the coat cured layer.

[Saponification]
(1) Immersion method An antireflection film is immersed in an alkaline solution under appropriate conditions to saponify all surfaces that are reactive with alkali on the entire surface of the film, requiring no special equipment. Therefore, it 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 opposite to the surface having the antireflection layer of the transparent substrate is hydrophilized. The protective film for polarizing plate is used by adhering the hydrophilic surface of a transparent substrate to a 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 of water on the surface of the transparent substrate opposite to the side having the high refractive index layer, the better from the viewpoint of adhesiveness to the polarizing film. Since the surface having the rate layer is damaged by the alkali, it is important to set the necessary minimum reaction conditions. As an index of the damage received by the antireflection layer due to alkali, particularly when using the contact angle with water of the surface of the transparent substrate opposite to the side having the antireflection structure layer, that is, the bonding surface of the antireflection film, 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, a problem arises in the adhesion to the polarizing film, which is not preferable. On the other hand, when the angle is less than 20 degrees, the damage received by the antireflection film is too large, and physical strength and light resistance are impaired.

(2) Alkaline liquid application method As a means for avoiding damage to the antireflection layer in the above-described immersion method, the alkaline liquid is applied only to the surface opposite to the surface having the antireflection layer under appropriate conditions, heated, washed with water, A drying alkali 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, contacting 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, peeling, etc. caused by alkali solution, so it is not desirable to use the immersion method, but this coating method does not contact the solution and should be used without problems. 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 bonding process with the polarizing plate made of the transparent base material that has been unwound in the same manner.

[Polarizer]
The preferable polarizing plate of this invention has the antireflection film (10) of this invention in at least one of the protective film (protective film for polarizing plates) of a polarizing film, as shown in FIG. In FIG. 5, the transparent support (1) of the antireflection film is adhered to the polarizing film (7) through the adhesive layer (6) made of polyvinyl alcohol, and the protective film (8) of the other polarizing film. Is bonded to the main surface opposite to the main surface to which the antireflection film of the polarizing film (7) is bonded via the adhesive layer (6). The other surface of the protective film (8) has a pressure-sensitive adhesive layer (9) on the surface main surface opposite to the main surface bonded to the polarizing film.
By using the antireflection film of the present invention as a protective film for a polarizing plate, a polarizing plate having an antireflection function excellent in physical strength and light resistance can be produced, and the cost can be greatly reduced and the display device can be thinned. .
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, a polarizing plate capable of improving the contrast in the bright room of the liquid crystal display device and greatly widening the vertical and horizontal viewing angles can be produced.

[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 preferred.
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.
An embodiment in which the optically anisotropic layer further contains a cellulose ester, an embodiment 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]
A polarizing plate having an antireflection film can be applied to an image display device such as a liquid crystal display device (LCD) or an electroluminescence display (ELD).
A polarizing plate having the antireflection film of the present invention as shown in FIG. 5 is used by adhering to the glass of the liquid crystal cell of the liquid crystal display device directly or via 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.

[Example 1]
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention should not be construed as being limited thereto.
(Preparation of coating liquid HC-1 for easily embossed hard coat precursor layer)
The following composition was put into a mixing tank and stirred to obtain a hard coat layer coating solution.
Add 48.0 parts by mass of methyl ethyl ketone and 12.0 parts by mass of cyclohexanone to 40.0 parts by mass of a 20:80 copolymer of methacrylic acid and allyl methacrylate having a mass average molecular weight of 45,000 (manufactured by Sankyo Chemical) and stirring. did. It filtered with the polypropylene filter with the hole diameter of 0.4 micrometer, and prepared coating liquid HC-1 for an easily embossable hard-coat precursor layer.

(Preparation of coating liquid HC-2 for easily embossed hard coat precursor layer)
750.0 parts by mass of trimethylolpropane triacrylate (Biscoat # 295 (manufactured by Osaka Organic Chemical Co., Ltd.)), 270.0 parts by mass of poly (glycidyl methacrylate) having a mass average molecular weight of 15000, 730.0 parts by mass of methyl ethyl ketone, 500 cyclohexanone 0.05 parts by mass and 50.0 parts by mass of a photopolymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) were added and stirred, filtered through a polypropylene filter having a pore size of 0.4 μm, and a hard coat layer. A coating solution was prepared.

(Preparation of easy embossing hard coat precursor layer coating film H-1)
A coating liquid HC-1 for easy embossing hard coat precursor layer is applied on a triacetyl cellulose film (TD80UF, manufactured by Fuji Photo Film Co., Ltd., glass transition temperature 160 to 170 ° C.) with a thickness of 80 μm using a gravure coater. And dried at 100 ° C. to form an easily embossable hard coat precursor layer having a thickness of 8 μm. The surface elastic modulus of the easily embossable hard coat precursor layer was 3.9 GPa.
The surface elastic modulus can be determined using a micro surface hardness tester (manufactured by Fischer Instruments Co., Ltd .: Fischer Scope H100VP-HCU). Specifically, a sample provided with an easily embossed layer of 10 μm or more under the same conditions as the film prepared on a glass substrate was prepared, and a diamond pyramid indenter (tip facing angle: 136 °) was used, and the indentation depth The indentation depth under an appropriate test load was measured in a range where the thickness did not exceed 0.5 μm or more, and was determined from the change in load and displacement at the time of unloading.

(Preparation of easily embossed hard coat precursor layer coating films H-2 to 4)
The coating liquid HC-2 for hard coat layer was applied on a triacetyl cellulose film (TD80UF, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm using a gravure coater. After drying at 100 ° C., an irradiance of 400 mW / cm using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less. ^2. An ultraviolet ray having an irradiation amount of 300 mJ / cm ² was irradiated to cure the coating layer, thereby forming an easily embossed hard coat precursor layer H-2 having a thickness of 8 μm.
Furthermore, the irradiation amount of ultraviolet rays was changed to 50 mJ / cm ² and 100 mJ / cm ² to prepare easy embossed hard coat precursor layer films H-3 and H-4. The surface elastic moduli of H-2 to H-4 were 5.0 GPa, 3.0 GPa, and 4.0 GPa, respectively.

(Preparation of titanium dioxide fine particle dispersion)
As the titanium dioxide fine particles, titanium dioxide fine particles (MPT-129C, manufactured by Ishihara Sangyo Co., Ltd., TiO ₂ : Co ₃ O ₄ : containing cobalt and subjected to surface treatment using aluminum hydroxide and zirconium hydroxide: Al ₂ O ₃ : ZrO ₂ = 90.5: 3.0: 4.0: 0.5 mass ratio) was used.
The following dispersant (41.1 parts by mass) and cyclohexanone (701.8 parts by mass) were added to 257.1 parts by mass of the particles and dispersed by dynomill to prepare a titanium dioxide dispersion having a mass average diameter of 70 nm.

Dispersant

(Preparation of coating solution for medium refractive index layer)
In 99.1 parts by mass of the above titanium dioxide dispersion, 68.0 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA), 3.6 parts by mass of a photopolymerization initiator (Irgacure 907), light A sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1.2 parts by mass, 279.6 parts by mass of methyl ethyl ketone and 1049.0 parts by mass of cyclohexanone were added and stirred. After sufficiently stirring, the solution was filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a coating solution for a medium refractive index layer.

(Preparation of coating solution for high refractive index layer)
To 469.8 parts by mass of the above titanium dioxide dispersion, 40.0 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.), a photopolymerization initiator (Irgacure 907) Ciba Specialty Chemicals Co., Ltd.) 3.3 parts by mass, photosensitizer (Kayacure-DETX, Nippon Kayaku Co., Ltd.) 1.1 parts by mass, methyl ethyl ketone 526.2 parts by mass, and cyclohexanone 459 .6 parts by mass was added and stirred. The solution was filtered through a polypropylene filter having a pore diameter of 0.4 μm to prepare a coating solution for a high refractive index layer.

(Preparation of coating solution for low refractive index layer)
The following perfluoroolefin copolymer (1) is dissolved in methyl isobutyl ketone so as to have a concentration of 7% by mass, and the terminal methacrylate group-containing silicone resin X-22-164C (manufactured by Shin-Etsu Chemical Co., Ltd.) is added to the solid content. On the other hand, 3% of the photo radical generator Irgacure 907 (trade name) was added in an amount of 5% by mass based on the solid content to prepare a coating solution for a low refractive index layer.

(Synthesis of the perfluoroolefin copolymer (1))
Into a stainless steel autoclave with a stirrer 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. Furthermore, 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 5.4 kg / cm ² . The reaction was continued for 8 hours while maintaining the temperature, and when the pressure reached 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 perfluoroolefin copolymer (1). The resulting polymer had a refractive index of 1.421.

(Preparation of antireflection film 101)
Three coating solutions for the medium refractive index layer, the coating solution for the high refractive index layer, and the coating solution for the low refractive index layer are formed on the easily embossed hard coat precursor layer films H-1 and H-2 to 4 prepared above. The coating was continuously performed using a gravure coater having a coating station.

The medium refractive index layer was dried at 90 ° C. for 30 seconds, and the ultraviolet curing condition was 180 W / cm air-cooled metal halide lamp (eye graphics) while purging with nitrogen so that the atmosphere had an oxygen concentration of 1.0% by volume or less. ), And the irradiation dose was 400 mW / cm ² and the irradiation dose was 400 mJ / cm ² .
The medium refractive index layer after curing had a refractive index of 1.630 and a film thickness of 67 nm.

The drying condition of the high refractive index layer is 90 ° C. for 30 seconds, and the ultraviolet curing condition is 240 W / cm air-cooled metal halide lamp (eye graphics) while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less. ), And the irradiation dose was 600 mW / cm ² and the irradiation dose was 400 mJ / cm ² .
The cured high refractive index layer had a refractive index of 1.905 and a film thickness of 107 nm.

The low refractive index layer was dried at 90 ° C. for 30 seconds, and the ultraviolet curing condition was 240 W / cm air-cooled metal halide lamp (eye graphics) while purging with nitrogen so that the atmosphere had an oxygen concentration of 0.1% by volume or less. ), And the irradiation amount was 600 mW / cm ² and the irradiation amount was 600 mJ / cm ² .
The low refractive index layer after curing had a refractive index of 1.440 and a film thickness of 85 nm. In this way, antireflection films 101 and 102 to 104 were produced.

The surface elastic moduli of the easily embossable hard coat precursor layer after irradiation with the same ultraviolet rays as in the preparation of the antireflection layer were 3.9 GPa, 5.0 GPa, 4.2 GPa, and 4.7 GPa, respectively.
Here, the surface elastic modulus of the easily embossable hard coat precursor layer after ultraviolet irradiation is determined by forming the antireflection layer without applying the antireflection layer after coating the easily embossable hard coat precursor layer on the transparent substrate. It is the surface elastic modulus of the easily embossed hard coat precursor layer cured by irradiating with ultraviolet rays under the same conditions as described above (the same applies after the electron beam irradiation).

(Embossing, production of antiglare antireflection film)
The anti-reflection film 101-104 produced above is nipped with a 100 mmφ metal embossing roller and a 100 mmφ MC nylon backup roller to form the irregular shape formed on the roll surface of the embossing roller into an antireflection film. Transcribed. Furthermore, using an electron beam irradiator (EC250 / 15 / 180L manufactured by Iwasaki Electric Co., Ltd.), 15 MRad electron beam was irradiated at an acceleration voltage of 100 kV under the condition of an oxygen concentration of 300 ppm to produce antireflection films 101 to 104 with an antiglare function. . The surface elastic modulus of the easily embossed hard coat precursor layer cured by electron ship irradiation was 5.0 GPa.
The embossing roller unevenness RSm was 15 μm and Ra was 0.4 μm. The transfer processing speed in this transfer operation was 1 m / min, and the roll surface temperature of the embossing roller was 130 ° C. The clearance between the embossing roller and the backup roller was 0.1 mm, and the press pressure (linear pressure) was 9800 N / cm.

(Evaluation)
The following evaluation was implemented with respect to the produced anti-reflective film with an anti-glare function. The results are shown in Table 1.
[Arithmetic mean roughness]
The arithmetic average roughness (Ra) of the outermost surface side of the antireflection layer surface of the film was measured using a “Micromap” machine manufactured by RYOKA SYSTEM Co., Ltd., on the uneven surface of the film provided with antiglare properties.

[Average reflectance]
Using a spectrophotometer (manufactured by JASCO Corporation), the spectral reflectance at an incident angle of 5 ° was measured in a wavelength region of 380 to 780 nm. The mirror surface average reflectance of 450-650 nm was used for the result.

[Pencil hardness evaluation]
After the antireflection film was conditioned at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, the pencil hardness was evaluated by the method described in JIS K 5400. The load was 4.9N.

[Glitter evaluation]
The produced antireflection film with antiglare function was placed on a cell imitating 200 ppi (200 pixels / inch) at a distance of 1 mm, and the degree of glare (brightness variation caused by surface protrusions of the antireflection film) was determined. Visual evaluation was performed according to the following criteria.
◎: No glare is observed at all ○: Almost no glare is observed △: There is slight glare ×: There is an unpleasant glare

[Anti-glare evaluation]
The produced antiglare antireflection film was projected on a bare fluorescent lamp (8000 cd / m ² ) without a louver, and the degree of blur of the reflected image of the fluorescent lamp was visually evaluated according to the following criteria.
○: Fluorescent light is clearly blurred (anti-glare property is sufficient)
Δ: Fluorescent light is blurred (anti-glare)
X: Fluorescent lamp is hardly blurred (insufficient anti-glare property)

  As a result of comparing the concavo-convex shape transferred to the produced antiglare antireflection film, as in Samples 101, 103, 104, what was subjected to final curing of the easy-embossing hard coat precursor layer after providing concavo-convex by pressing, An embossing roller with a similar RSm of 15 μm and Ra of 0.4 μm was transferred. Also, from Table 1, these samples had low reflectance and excellent antiglare properties. In particular, a sample having a surface elastic modulus of 4.5 Gpa or less before pressing was excellent. On the other hand, sample 102 is inferior in antiglare property and reflectivity because it has a final hardness (5.0 Gpa) when an easily embossed hard coat precursor layer is applied.

[Example 2]
In the production of the antireflection films 101 and 103 produced in Example 1, the ultraviolet irradiation amount for producing the antireflection layer was changed to 0.9, 1.1, and 1.2 times for each layer, and the conditions for producing the antireflection layer were changed. The stability of anti-glare performance was tested. The results are shown in Table 2.
Curing of antireflection layer when easy embossing hard coat precursor layer contains polymer having repeating unit represented by general formula (1) and further does not contain a polymerization initiator that starts curing by means of curing antireflection layer It was particularly excellent in pencil hardness and antiglare stability when conditions changed.

[Example 3]
Transparent base materials B-1 and B-2 containing an ultraviolet absorber (UV-1, UV-2) having a benzotriazole skeleton as an additive for a triacetyl cellulose film, a transparent base material B-3 from which this is removed, and benzophenone A transparent base material B-4 containing a skeleton UV absorber (UV-3) was produced as follows. B-1, B-2, and B-4 were added in amounts so that the transmittance at 380 nm was 1%.

[Dope composition]
Triacetyl cellulose (substitution degree 2.84, viscosity average polymerization degree 306, water content 0.2 mass%, viscosity 6 mass% in dichloromethane solution 315 mPa · s, average particle diameter 1.5 mm, standard deviation 0.5 mm 100 parts by weight methylene chloride (first solvent) 320 parts by weight methanol (second solvent) 83 parts by weight 1-butanol (third solvent) 3 parts by weight plasticizer A (triphenyl phosphate) 7.6 parts by weight Part plasticizer B (biphenyldiphenyl phosphate) 3.8 parts by weight UV-1 1.0 part by weight citrate ester mixture (citric acid, monoethyl ester, diethyl ester, triethyl ester mixture) 0.006 parts by weight fine particles (silicon dioxide (Particle size 15 nm), Mohs hardness about 7)
0.05 parts by mass

A dope having the above composition was cast to prepare a transparent substrate B-1.
Furthermore, transparent substrate B-2 in which UV-1 was changed to UV-2, transparent substrate B-3 in which UV-1 was removed, and B-4 in which UV-1 was changed to B-3 were prepared. The addition amount of the UV agent was adjusted so that the transmittance at 380 nm was 1%.

  An antireflection film with an antiglare function was produced on these transparent substrates in the same manner as the sample 101 of Example 1. A sample using a transparent base material containing no benzotriazole skeleton UV absorber had small yellowing after electron beam irradiation and excellent visibility.

[Example 4]
(Preparation of protective film for polarizing plate)
A saponification solution in which a 1.5 mol / l sodium hydroxide aqueous solution was kept at 50 ° C. was prepared. Furthermore, a 0.005 mol / l dilute sulfuric acid aqueous solution was prepared.
In the antiglare antireflection film prepared in Example 1, the surface of the transparent support opposite to the side having the high refractive index layer of the present invention was saponified using the saponification solution.
The aqueous sodium hydroxide solution on the surface of the saponified transparent support is thoroughly washed with water, then washed with the above-mentioned diluted sulfuric acid aqueous solution, and further, the diluted sulfuric acid aqueous solution is thoroughly washed with water and sufficiently dried at 100 ° C. It was.
When the contact angle of the surface of the saponified transparent support on the side opposite to the side having the high refractive index layer of the antireflection film was evaluated, it was 40 degrees or less. Thus, the protective film for polarizing plates was produced.

(Preparation of polarizing plate)
A polyvinyl alcohol film having a thickness of 75 μm (manufactured by Kuraray Co., Ltd.) was immersed in an aqueous solution consisting of 1000 parts by mass of water, 7 parts by mass of iodine, and 105 parts by mass of potassium iodide to adsorb iodine.
Subsequently, this film was uniaxially stretched 4.4 times in the longitudinal direction in a 4% by mass boric acid aqueous solution, and then dried in a tension state to produce a polarizing film.
A saponified triacetyl cellulose surface of the antireflection film of the present invention (protective film for polarizing plate) was bonded to one surface of the polarizing film using a polyvinyl alcohol-based adhesive as an adhesive. Further, a triacetyl cellulose film saponified in the same manner as described above was bonded to the other surface of the polarizing film using the same polyvinyl alcohol-based adhesive.

(Evaluation of image display device)
The TN, STN, IPS, VA, OCB mode transmission type, reflection type, or transflective type liquid crystal display device equipped with the polarizing plate of the present invention thus produced has excellent antireflection performance and is extremely Visibility was excellent. In particular, the effect is remarkable in the VA mode.

[Example 5]
(Preparation of polarizing plate)
The disc surface of the discotic structural unit is inclined with respect to the transparent support surface, and the angle formed by the disc surface of the discotic structural unit and the transparent support surface changes in the depth direction of the optical anisotropic layer. In an optical compensation film having an optical compensation layer (wide view film SA-12B, manufactured by Fuji Photo Film Co., Ltd.), the surface opposite to the side having the optical compensation layer was saponified under the same conditions as in Example 4. .
The polarizing film produced in Example 4 was saponified with the antireflection film (protective film for polarizing plate) produced in Example 4 on one surface of the polarizing film using a polyvinyl alcohol-based adhesive as an adhesive. The triacetyl cellulose surface was bonded. Further, the triacetyl cellulose surface of the saponified optical compensation film was bonded to the other surface of the polarizing film using the same polyvinyl alcohol adhesive.

(Evaluation of image display device)
The TN, STN, IPS, VA, OCB mode transmissive, reflective, or transflective liquid crystal display device equipped with the polarizing plate of the present invention thus fabricated does not use an optical compensation film. Compared with a liquid crystal display device equipped with a polarizing plate, the contrast in the bright room was excellent, the viewing angles of the top, bottom, left and right were very wide, the antireflection performance was excellent, and the visibility and display quality were extremely excellent.
The effect was particularly remarkable in the VA mode.

It is a figure which shows an example of the transfer apparatus (uneven | corrugated transfer apparatus) which performs embossing to the antireflection film of this invention, and a hardening apparatus. It is sectional drawing which shows an example of the anti-glare antireflection film to which the uneven | corrugated shape was transcribe | transferred. It is another aspect of the uneven | corrugated transfer apparatus, and is the schematic diagram comprised by the plate mold and the supporting member. It is a figure which shows an example of the apparatus which performs coating and hardening of the antireflection layer of the antireflection film of this invention. It is a figure which shows an example which used the antireflection film of this invention for the polarizing plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent support 6 Adhesive layer 7 Polarizing film 8 Protective film 9 Adhesive layer 10 Antireflection film 16 Transfer apparatus 17 Curing apparatus 20 Transparent base material 24 Antireflection layer 25 Easily embossable hard coat precursor layer 30 Antireflection film 32 Antireflection Anti-glare film 34 Embossed roller 34A Convex part on roller surface 34B Concave part on roller surface 36 Backup roller 72 Support member 74 Support base 70 Plate 80 Irradiation chamber 101 Roll film delivery 102 First coating station 103 First drying zone(
104 First UV irradiation machine 105 Second coating station 106 Second drying zone 107 Second UV irradiation machine 108 Third coating station 109 Third drying zone 110 Third UV irradiation machine 111 Post-drying zone 112 Winding

Claims (10)

In the production of an antireflection film having an antireflection layer comprising at least one layer on a transparent substrate, the method for producing an antireflection film comprising the following steps (1) to (4) in order.
(1) A step of coating at least one easily embossable hard coat precursor layer on a transparent substrate;
(2) a step of coating an antireflection layer on the easily embossed hard coat precursor layer and curing the antireflection layer;
(3) a step of forming irregularities on the antireflection layer side film surface by pressing,
(4) A step of curing the easily embossable hard coat precursor layer by means different from the means for curing the antireflection layer.   2. The method for producing an antireflection film according to claim 1, wherein the means for curing the easily embossable hard coat precursor layer, which is a means different from the means for curing the antireflection layer, is electron beam irradiation.   3. The method for producing an antireflection film according to claim 1, wherein unevenness is provided by pressing with a plate of 0.01 ≦ Ra ≦ 2.0 μm, 5 ≦ RSm ≦ 60 μm.   4. The method for producing an antireflection film according to claim 1, wherein pressing is performed at a temperature not higher than the glass transition temperature of the transparent substrate.   An antireflection film produced by the method according to claim 1. The easily embossed hard coat cured layer obtained by curing the easily embossable hard coat precursor layer contains at least one compound having a repeating unit represented by the following general formula (1). Antireflection film.
General formula (1)
In the general formula (1), R ² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. P ² is a monovalent group containing an ethylenically unsaturated group, and L ² is a single bond or a divalent linking group.   The antireflection film according to claim 5, wherein the arithmetic average roughness (Ra) of the outermost surface opposite to the transparent substrate surface is 0.05 to 0.5 μm.   The antireflection film according to claim 5, wherein the transparent substrate substantially does not contain an ultraviolet absorber having a benzotriazole skeleton.   The antireflection film in any one of Claims 5-8 is used for one of the two protective films in a polarizing plate, The polarizing plate characterized by the above-mentioned.   An image display device, wherein the antireflection film according to claim 5 or the polarizing plate according to claim 9 is used on the outermost surface of the display.