JP7377311B2 - Optical laminate, polarizing plate, image display device, and method for producing optical laminate - Google Patents

Description

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

The antireflection film is a transparent film that has antireflection properties. Conventionally, an optical laminate including a multilayer film in which a high refractive index layer and a low refractive index layer are successively laminated on a transparent substrate has been used as an antireflection film. The antireflection film is provided, for example, on the display screen of a display device such as a liquid crystal display (LCD), a plasma display (PDP), or an organic EL display (OELD). Thereby, it is possible to reduce the reflectance of the display screen using the principle of optical interference, thereby suppressing a decrease in contrast and image reflection due to reflection of external light on the display screen.

Furthermore, as an antireflection film, an AGAR type film that has antiglare (AG) as well as antireflection (AR) properties has also been developed. In order to impart anti-glare properties to anti-reflection films, a technology has been proposed in which a rough surface structure is formed using micro-order fine particles (filler) on the film surface, and the rough surface structure scatters incident light. .

For example, in Patent Document 1, in order to impart anti-glare properties to an anti-reflection film, matte particles of 1 to 10 μm are dispersed and contained in an anti-glare hard coat layer, which is a high refractive index layer. A technique is disclosed in which a protrusion structure having dome-shaped protrusions corresponding to the shape of the matte particles is formed on the surface of an antireflection film. Furthermore, Patent Document 2 discloses a technique in which an anti-glare layer contains transparent fine particles or an inorganic filler with a diameter of 2 to 5 μm to form a protrusion-like structure having dome-shaped protrusions on the film surface. .

Patent No. 5331919 Patent No. 4431540

However, if a protruding structure is formed on the surface of the anti-reflection film as described in Patent Documents 1 and 2 above in order to impart anti-glare properties to the anti-reflection film, the scratch resistance of the anti-reflection film will deteriorate. There was a problem with the decline. For example, when an anti-reflection film is provided on a display screen such as a touch panel of a smartphone or various operating devices, the load applied to the surface screen by the operator's fingers or pointing device will be concentrated on the protruding parts of the protruding structure. Put it away. For this reason, there was a problem in that the protruding structure was easily scratched and scratched, and the scratch resistance of the film surface was reduced. Therefore, in the past, protruding structures were eliminated as much as possible on the surface of the antireflection film to form a dimple-like rough surface structure, thereby maintaining anti-glare properties and improving the scratch resistance of the film surface. There has been a desire for an optical laminate that can.

The present invention has been made in view of the above problems, and provides an optical laminate, a polarizing plate equipped with the same, and an optical laminate capable of improving scratch resistance while maintaining anti-glare properties. The present invention aims to provide a method for manufacturing a display device and an optical laminate.

In order to solve the above problems, according to a certain aspect of the present invention,
a transparent base material,
at least one or more hard coat layer formed on the transparent base material and made of a resin composition;
at least one metal oxide layer formed on the hard coat layer and made of a metal oxide;
at least one antifouling layer provided on the metal oxide layer and containing a fluorine-based organic compound;
Equipped with
An uneven structure is randomly formed on the surface of the hard coat layer on the metal oxide layer side,
An optical laminate is provided in which the height distribution of the surface of the uneven structure satisfies the following formula (1).
A/1.9 < P...(1)
A: Height of the highest point on the surface of the uneven structure when the height B of the lowest point on the surface of the uneven structure is 0 [μm]
P: the mode of the height distribution of the surface of the uneven structure when the height B of the lowest point on the surface of the uneven structure is 0 [μm]

The height difference between the tops of the plurality of convex portions constituting the uneven structure of the hard coat layer may be within 0.5 μm .

The outermost surface of the optical laminate has an uneven surface that follows the shape of the uneven structure of the hard coat layer,
The height difference between the tops of the plurality of convex portions constituting the uneven surface may be within 0.5 μm .

The height difference of the uneven structure of the hard coat layer may be ±0.3 μm or less with respect to a reference plane of the tops of the convex portions forming the uneven structure.

The outermost surface of the optical laminate has an uneven surface that follows the shape of the uneven structure of the hard coat layer,
The height difference of the uneven structure constituting the uneven surface may be ±0.3 μm or less with respect to a reference plane of the top of the convex portion forming the uneven structure .

The surface roughness Sa of the uneven structure of the hard coat layer may be 50 nm or more and 300 nm or less.

Using a friction tester using steel wool, the steel wool was rubbed against the surface of the optical laminate under the conditions of load: 1 kg, contact area: 1 cm x 1 cm, and reciprocating motion: 2000 times. The contact angle of the outermost surface of the optical laminate with water may be 90 degrees or more.

The external haze value specified by JIS K7136 may be 3% or more and 40% or less.

The hard coat layer may include metal oxide fine particles having an average particle size of 20 nm or more and 100 nm or less.

The hard coat layer does not need to contain filler particles having an average particle size of 1 μm or more.

The metal oxide layer includes an antireflection layer,
The antireflection layer is composed of a laminate in which low refractive index layers and high refractive index layers having a higher refractive index than the low refractive index layers are alternately laminated,
The optical laminate may be an antireflection film having an antiglare function and an antireflection function.

The metal oxide layer may include an adhesion layer provided between the hard coat layer and the antireflection layer.

In order to solve the above problems, according to another aspect of the present invention,
A polarizing plate is provided that includes the optical laminate described above.

In order to solve the above problems, according to another aspect of the present invention,
An image display device including the optical laminate described above is provided.

In order to solve the above problems, according to another aspect of the present invention,
A method for manufacturing the optical laminate, comprising:
providing a hard coat layer made of a resin composition on a transparent substrate;
providing at least one metal oxide layer on the hard coat layer;
providing an antifouling layer on the metal oxide layer;
including;
The step of providing the hard coat layer includes:
applying the resin composition on the surface of the transparent base material;
a step of transferring an uneven shape of a transfer mold having a random uneven shape to the resin composition;
A method for manufacturing an optical laminate is provided.

According to the present invention, it is possible to improve scratch resistance while maintaining anti-glare properties.

FIG. 1 is a cross-sectional view showing an optical laminate according to an embodiment of the present invention. It is a sectional view showing an example of the hard coat layer concerning the same embodiment. It is a figure showing a 3D image of an example of an optical layered product concerning the same embodiment. It is a figure which shows the cross-sectional roughness of an example of the optical laminated body based on the same embodiment. It is a flow chart which shows the manufacturing method of the optical layered product concerning the same embodiment. It is a process diagram explaining an example of the manufacturing method of the transfer mold based on the same embodiment. FIG. 3 is a process diagram illustrating a coating process and a transfer process according to the same embodiment. FIG. 7 is a diagram showing a histogram of sample A according to a comparative example. FIG. 7 is a diagram showing a histogram of sample B according to a comparative example. FIG. 7 is a diagram showing a histogram of sample C according to a comparative example. FIG. 7 is a diagram showing a histogram of sample D according to a comparative example. FIG. 7 is a diagram showing a histogram of sample E according to a comparative example. FIG. 7 is a diagram showing a histogram of sample K according to a comparative example. It is a figure which shows the histogram of the sample F based on an Example. It is a figure showing the histogram of sample G concerning an example. It is a figure which shows the histogram of the sample H based on an Example. It is a figure which shows the histogram of the sample I based on an Example. It is a figure which shows the histogram of the sample J based on an Example.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in these embodiments are merely illustrative to facilitate understanding of the invention, and do not limit the invention unless otherwise specified. In this specification and the drawings, elements with substantially the same functions and configurations are given the same reference numerals to omit redundant explanation, and elements not directly related to the present invention are omitted from illustration. do.

Note that in the drawings referred to in the following description, the sizes of some of the components may be exaggerated for convenience of explanation. Therefore, the relative sizes of the constituent elements illustrated in each drawing do not necessarily accurately represent the actual size relationship between the constituent elements.

[1. Overall configuration of optical laminate]
First, with reference to FIG. 1, the overall configuration of an optical laminate 10 according to an embodiment of the present invention will be described. FIG. 1 is a cross-sectional view showing an optical laminate 10 according to this embodiment.

The optical laminate 10 according to the present embodiment is used, for example, as an AGAR type antireflection film having an antiglare function (AG) and an antireflection function (AR). As shown in FIG. 1, the optical laminate 10 according to the present embodiment includes a transparent base material 11, a hard coat layer 12, an adhesive layer 13, an antireflection layer 14, and an antifouling layer 15, which are laminated in this order. It is something that has been done. Each layer will be explained below.

[Transparent base material 11]
The transparent base material 11 is formed of, for example, a transparent material that can transmit light in the visible light range having a wavelength of 350 to 830 nm. Note that in this embodiment, the "transparent material" is a material that has a transmittance of light in the used wavelength range of 80% or more, for example, within a range that does not impair the effects of the optical laminate 10 according to this embodiment.

The transparent base material 11 may be made of, for example, a plastic film as an organic material, or a glass film as an inorganic material. The constituent materials of the plastic film are polyester resin, acetate resin, polyethersulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, (meth)acrylic resin, polyvinyl chloride resin, Any one or more of polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate resin, and polyphenylene sulfide resin, preferably polyester resin, acetate resin, or polycarbonate resin. Any one or more of a resin and a polyolefin resin. In addition, in this embodiment, "(meth)acrylic" means methacryl and acrylic.

The transparent base material 11 is made of, for example, polycarbonate (PC), polyethylene terephthalate (PET), triacetyl cellulose (TAC), polyimide (PI), polymethyl methacrylate (PMMA), cycloolefin polymer (COP), cycloolefin copolymer ( COC), and one or more selected from the group of glass.

In this embodiment, an example in which the transparent base material 11 is made of triacetyl cellulose (TAC) will be described. When the transparent base material 11 is made of TAC, when the hard coat layer 12 is formed on one side thereof, a permeation layer is formed in which a part of the components constituting the hard coat layer 12 permeates. As a result, the adhesion between the transparent base material 11 and the hard coat layer 12 is improved, and the occurrence of interference fringes due to the difference in refractive index between the layers can be suppressed.

Further, the transparent base material 11 may contain a reinforcing material as long as the optical properties are not significantly impaired. Examples of the reinforcing material include cellulose nanofibers and nanosilica.

Moreover, the transparent base material 11 may be a film provided with one or both of an optical function and a physical function. Examples of films having one or both of optical and physical functions include polarizing plates, retardation compensation films, heat ray blocking films, transparent conductive films, brightness enhancement films, barrier property improvement films, etc. .

The thickness of the transparent base material 11 is not particularly limited, but from the viewpoint of handleability, flexibility, cost, and characteristics, it is, for example, 10 μm or more and 500 μm or less, preferably 25 μm or more and 188 μm or less, and more preferably is 40 μm or more and 100 μm or less.

When the thickness of the transparent base material 11 is 25 μm or more, the rigidity of the base material itself is ensured, and wrinkles are less likely to occur even when stress is applied to the optical laminate 10. Moreover, it is preferable that the thickness of the transparent base material 11 is 25 μm or more, since even if the hard coat layer 12 is continuously formed on the transparent base material 11, wrinkles are unlikely to occur and there are few manufacturing concerns. When the thickness of the transparent base material 11 is 40 μm or more, wrinkles are even less likely to occur, which is preferable.

When using a roll when manufacturing the optical laminate 10, the thickness of the transparent base material 11 is preferably 1,000 μm or less, more preferably 600 μm or less. When the thickness of the transparent base material 11 is 1000 μm or less, the optical laminate 10 that is being manufactured and the optical laminate 10 that has been manufactured can be easily wound into a roll, and the optical laminate 10 can be efficiently manufactured. Moreover, when the thickness of the transparent base material 11 is 1000 μm or less, the optical laminate 10 can be made thinner and lighter. When the thickness of the transparent base material 11 is 600 μm or less, the optical laminate 10 can be manufactured more efficiently, and further thinning and weight reduction are possible, which is preferable.

The transparent base material 11 may be previously subjected to one or more of various treatments such as sputtering, corona discharge, ultraviolet irradiation, electron beam irradiation, chemical conversion, etching treatment such as oxidation, and undercoating treatment. By performing these treatments on the surface of the transparent base material 11 in advance, adhesion with the hard coat layer 12 formed on the transparent base material 11 can be improved. In addition, before forming the hard coat layer 12 on the transparent base material 11, the surface of the transparent base material 11 can be cleaned by solvent cleaning, ultrasonic cleaning, etc., as necessary. It is also preferable to remove dust and clean it.

[Hard coat layer 12]
Hard coat layer 12 is provided on transparent base material 11 . The hard coat layer 12 is an AG type hard coat layer, and a concavo-convex structure 30 is formed on the surface of the hard coat layer 12 for imparting anti-glare properties to the optical laminate 10. The hard coat layer 12 is made of a resin, for example, a cured product of a resin composition. The resin constituting the hard coat layer 12 is not particularly limited, but includes, for example, energy ray curable resins such as ultraviolet ray curable resins, electron beam curable resins, and infrared ray curable resins, thermosetting resins, thermoplastic resins, Examples include two-component mixed resins. Among these, it is preferable to use an ultraviolet curable resin that can efficiently form the hard coat layer 12 by irradiating ultraviolet rays.

Examples of the ultraviolet curable resin include acrylic, urethane, epoxy, polyester, amide, and silicone resins. Among these, it is preferable to use an acrylic material that provides high transparency when the laminated thin film is used for optical purposes, for example.

The acrylic ultraviolet curable resin is not particularly limited, but may be selected from monofunctional, bifunctional, trifunctional or higher polyfunctional acrylic monomers, oligomers, polymer components, etc. with hardness, adhesion, processability, etc. In view of the above, they can be appropriately selected and blended. Moreover, a photopolymerization initiator is blended into the ultraviolet curable resin.

Specific examples of monofunctional acrylate components include carboxylic acids (acrylic acid), hydroxys (2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate), alkyl or alicyclic monomers (isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, lauryl acrylate, stearyl acrylate, isobonyl acrylate, cyclohexyl acrylate), other functional monomers (2-methoxyethyl acrylate, methoxyethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl) Acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, N,N-dimethylaminoethyl acrylate, N,N-dimethylaminopropylacrylamide, N,N-dimethylacrylamide, acryloylmorpholine, N-isopropylacrylamide, N, N-diethylacrylamide, N-vinylpyrrolidone, 2-(perfluorooctyl)ethyl acrylate, 3-perfluorohexyl-2-hydroxypropyl acrylate, 3-perfluorooctyl-2-hydroxypropyl-acrylate, 2-(perfluorooctyl) decyl)ethyl acrylate, 2-(perfluoro-3-methylbutyl)ethyl acrylate), 2,4,6-tribromophenol acrylate, 2,4,6-tribromophenol methacrylate, 2-(2,4,6 -tribromophenoxy)ethyl acrylate), 2-ethylhexyl acrylate, nonylphenol EO-modified acrylate, and the like.

Specific examples of the bifunctional acrylate component include polyethylene glycol (600) diacrylate, dimethylol-tricyclodecane diacrylate, bisphenol AEO-modified diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, Propoxylated bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, 1,4-butanediol diacrylate, polyethylene glycol (200) diacrylate, tetraethylene glycol diacrylate, polyethylene glycol (400) diacrylate, cyclohexanedimethanol diacrylate, aliphatic urethane acrylate, polyether urethane acrylate, and the like. Specific examples available on the market include, for example, Sartomer Co., Ltd.'s product name "SR610".

Specific examples of trifunctional or higher functional acrylate components include pentaerythryl triacrylate (PETA), 2-hydroxy-3-acryloyloxypropyl methacrylate, isocyanuric acid EO-converted triacrylate, and ε-caprolactone modified tris-(2-acrylate). (oxyethyl) isocyanurate, trimethylolpropane triacrylate (TMPTA), ε-caprolactone-modified tris(acryloxyethyl)acrylate, tris-(2-acryloxyethyl)isocyanurate, and the like. Specific examples available on the market include Sartomer's trade name "CN968" and Sartomer's trade name "SR444."

Specific examples of the photopolymerization initiator include alkylphenone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, titanocene photopolymerization initiators, and the like. Specific examples available on the market include 1-hydroxycyclohexylphenyl ketone (IRGACURE184, BASF Japan Ltd.).

Further, the acrylic ultraviolet curable resin preferably contains a leveling agent in order to improve smoothness. Specific examples of the leveling agent include silicone leveling agents, fluorine leveling agents, acrylic leveling agents, and the like, and one or more of these can be used. Among these, it is preferable to use silicone leveling agents from the viewpoint of coating properties. Specific examples available on the market include BYK337 (polyether-modified polydimethylsiloxane) manufactured by BYK-Chemie Japan Co., Ltd., and the like.

Further, the solvent used for the acrylic ultraviolet curable resin is not particularly limited as long as it satisfies the coating properties of the resin composition, but it is preferably selected in consideration of safety. Specific examples of the solvent include propylene glycol monomethyl ether acetate, butyl acetate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl cellosolve acetate, ethyl lactate, methyl 3-methoxypropionate, 2-heptanone, cyclohexanone, Examples include ethyl carbitol acetate, butyl carbitol acetate, propylene glycol methyl ether, and one or more of these can be used. Among these, propylene glycol monomethyl ether acetate and butyl acetate are preferably used from the viewpoint of coating properties. In addition to the above, acrylic ultraviolet curing resins also include hue adjusting agents, coloring agents, ultraviolet absorbers, antistatic agents, various thermoplastic resin materials, refractive index adjusting resins, refractive index adjusting particles, and adhesive properties. A functional imparting agent such as a imparting resin can be contained.

Furthermore, fine metal oxide particles (not shown) may be dispersed and contained in the resin of the hard coat layer 12 . Here, the metal oxide fine particles contained in the hard coat layer 12 according to the present embodiment are micro-order filler particles (with an average particle size of 1 μm or more), they are nano-order fine particles (average particle size of less than 1 μm) that have a smaller particle size than filler particles. By containing nano-order metal oxide fine particles in the hard coat layer 12, the adhesion between the hard coat layer 12 and the adhesive layer 13 can be improved.

Metal oxide fine particles are particles of metal oxide. The average particle size of the metal oxide fine particles is preferably 800 nm or less, more preferably 20 nm or more and 100 nm or less. If the average particle size of the metal oxide fine particles is too large than 800 nm, it will be difficult to use the laminated thin film for optical purposes. On the other hand, if the average particle size of the metal oxide fine particles is too small than 20 nm, the adhesion between the hard coat layer 12 and the adhesive layer 13 will decrease. Therefore, by setting the average particle size of the metal oxide fine particles according to the present embodiment within the above range, the optical laminate 10 can be suitably applied to optical applications, and the adhesion between the hard coat layer 12 and the adhesive layer 13 is improved. can be improved. In addition, in this embodiment, the average particle diameter refers to a value measured by the BET method.

Further, the content of the metal oxide fine particles is preferably 20% by mass or more and 50% by mass or less based on the entire solid content of the resin composition of the hard coat layer 12. If the content of metal oxide fine particles is too small, the adhesion between the hard coat layer 12 and the adhesive layer 13 will decrease. On the other hand, if the content of metal oxide fine particles is too large, the flexibility etc. of the hard coat layer 12 will deteriorate. Therefore, by setting the content of the metal oxide fine particles according to the present embodiment within the above range, the adhesion between the hard coat layer 12 and the adhesive layer 13 can be maintained while suppressing the deterioration of the flexibility etc. of the hard coat layer 12. can be improved. Note that the solid content of the resin composition refers to all components other than the solvent, and liquid monomer components are also included in the solid content.

Specific examples of metal oxides constituting the metal oxide fine particles include SiO ₂ (silica), Al ₂ O ₃ (alumina), TiO ₂ (titania), ZrO ₂ (zirconia), CeO ₂ (ceria), and MgO ( Magnesia), ZnO, Ta ₂ O ₅ , Sb ₂ O ₃ , SnO ₂ , MnO ₂ and the like. Among these, it is preferable to use silica, which provides high transparency when the laminated thin film is used for optical purposes, for example. Specific examples available on the market include, for example, the product name "IPA-ST-L" (silica sol) manufactured by Nissan Chemical Co., Ltd. Further, a functional group such as an acrylic group or an epoxy group may be introduced onto the surface of the metal oxide fine particles for the purpose of increasing adhesion or affinity with the resin.

Further, the hard coat layer 12 according to the present embodiment may contain the nano-order metal oxide fine particles described above, but filler particles having an average particle size of 1 μm or more (containing the conventional filler particles described in Patent Documents 1 and 2 above) (micro-order particles to form protrusion-like structures). However, even if the hard coat layer 12 according to the present embodiment does not contain filler particles, the uneven structure 30 is formed on the surface on the adhesive layer 13 side, so the uneven structure 30 provides the optical laminate 10 with anti-glare properties. can be granted. Note that the configuration of the uneven structure 30 of the hard coat layer 12 and the method for forming the uneven structure 30 will be described in detail later.

The thickness of the hard coat layer 12 is not particularly limited, but is preferably, for example, 0.5 μm or more, more preferably 1 μm or more. When the thickness of the hard coat layer 12 is 0.5 μm or more, sufficient hardness is obtained, so that scratches during manufacturing are less likely to occur. Further, the thickness of the hard coat layer 12 is preferably 100 μm or less. When the thickness of the hard coat layer 12 is 100 μm or less, the optical laminate 10 can be made thinner and lighter. Further, when the thickness of the hard coat layer 12 is 100 μm or less, microcracks in the hard coat layer 12 that occur when the optical laminate 10 is bent during manufacture are less likely to occur, resulting in good productivity.

The hard coat layer 12 may be a single layer or may be a stack of multiple layers. Furthermore, the hard coat layer 12 may be further provided with known functions such as ultraviolet absorption performance, antistatic performance, refractive index adjustment function, and hardness adjustment function. Further, the functions provided to the hard coat layer 12 may be provided in a single hard coat layer, or may be provided in a plurality of divided hard coat layers.

[Adhesion layer 13]
The adhesion layer 13 is a layer formed to improve the adhesion between the hard coat layer 12, which is an organic film, and the antireflection layer 14, which is an inorganic film. The adhesive layer 13 is preferably made of an oxygen-deficient metal oxide or metal. The metal oxide in an oxygen-deficient state refers to a metal oxide in a state in which the number of oxygen atoms is insufficient compared to the stoichiometric composition. Examples of metal oxides in an oxygen-deficient state include SiOx, AlOx, TiOx, ZrOx, CeOx, MgOx, ZnOx, TaOx, SbOx, SnOx, MnOx, and the like. Further, examples of the metal include Si, Al, Ti, Zr, Ce, Mg, Zn, Ta, Sb, Sn, Mn, and In. The adhesion layer 13 may be, for example, one in which x in SiOx is greater than 0 and less than 2.0. Further, the adhesive layer 13 may be formed from a mixture of multiple types of metals or metal oxides.

Note that when the adhesive layer 13 is made of SiOx, the refractive index of the adhesive layer 13 is preferably 1.20 to 1.60. In other words, when the adhesion layer 13 is made of SiOx, the adhesion layer 13 also functions as a low refractive index layer 14b, which will be described later.

From the viewpoint of maintaining transparency and adhesion with the antireflection layer 14 and obtaining good optical properties, the thickness of the adhesive layer 13 is preferably more than 0 nm and less than 20 nm, and preferably more than 1 nm and less than 10 nm. It is particularly preferable that there be.

Note that it is preferable to provide the adhesion layer 13 between the hard coat layer 12 and the antireflection layer 14 because the adhesion between both layers can be improved. However, the adhesion layer 13 is not essential, and the antireflection layer 14 may be directly laminated on the hard coat layer 12.

[Anti-reflection layer 14]
The antireflection layer 14 is an example of a metal oxide layer provided on the hard coat layer 12. The antireflection layer 14 is an example of an optical functional layer. The antireflection layer 14 is a laminate that exhibits an antireflection function. As shown in FIG. 1, the antireflection layer 14 is made of a laminate in which low refractive index layers 14b and high refractive index layers 14a are alternately laminated. In this embodiment, the antireflection layer 14 is a laminate of a total of four layers in which high refractive index layers 14a and low refractive index layers 14b are alternately laminated in order from the adhesive layer 13 side. The number of high refractive index layers 14a and low refractive index layers 14b is not particularly limited, and the number of high refractive index layers 14a and low refractive index layers 14b can be any number of layers.

As shown in FIG. 1, the antifouling layer 15 is in contact with the low refractive index layer 14b that constitutes the antireflection layer 14. Therefore, light incident from the antifouling layer 15 side is diffused by the antireflection layer 14. This provides an antireflection function that prevents light incident from the antifouling layer 15 side from being reflected in one direction.

The low refractive index layer 14b preferably contains an oxide of Si from the viewpoint of availability and cost, and is preferably a layer containing SiO ₂ (an oxide of Si) or the like as a main component. The SiO ₂ single layer film is colorless and transparent. In this embodiment, the main component of the low refractive index layer 14b means a component contained in the low refractive index layer 14b in an amount of 50% by mass or more.

When the low refractive index layer 14b is a layer containing Si oxide as a main component, it may contain less than 50% by mass of another element. The content of elements other than Si oxide is preferably 10% or less. Other elements may include, for example, Na for the purpose of improving durability, Zr, Al, and N for the purpose of improving hardness, and Zr and Al for improving alkali resistance.

The refractive index of the low refractive index layer 14b is preferably 1.20 to 1.60, more preferably 1.30 to 1.50. Examples of the dielectric material used for the low refractive index layer 14b include magnesium fluoride (MgF ₂ , refractive index 1.38).

The refractive index of the high refractive index layer 14a is preferably 2.00 to 2.60, more preferably 2.10 to 2.45. Examples of dielectric materials used in the high refractive index layer 14a include niobium pentoxide (Nb ₂ O ₅ , refractive index 2.33), titanium oxide (TiO ₂ , refractive index 2.33 to 2.55), and tungsten oxide (WO ₃ , refractive index 2.2), cerium oxide (CeO ₂ , refractive index 2.2), tantalum pentoxide (Ta ₂ O ₅ , refractive index 2.16), zinc oxide (ZnO, refractive index 2.1), Examples include indium tin oxide (ITO, refractive index 2.06) and zirconium oxide (ZrO ₂ , refractive index 2.2).

If it is desired to impart conductive properties to the high refractive index layer 14a, for example, ITO, indium zinc oxide (IZO) can be selected.

It is preferable that the antireflection layer 14 is made of, for example, niobium pentoxide (Nb ₂ O ₅ , refractive index 2.33) as the high refractive index layer 14a, and made of SiO ₂ as the low refractive index layer 14b. .

The film thickness of the low refractive index layer 14b may be in the range of 1 nm or more and 200 nm or less, and is appropriately selected depending on the wavelength range that requires an antireflection function.

The film thickness of the high refractive index layer 14a may be, for example, 1 nm or more and 200 nm or less, and is appropriately selected depending on the wavelength range that requires an antireflection function.

The film thicknesses of the high refractive index layer 14a and the low refractive index layer 14b can be appropriately selected depending on the design of the antireflection layer 14, respectively. For example, in order from the adhesive layer 13 side, the high refractive index layer 14a with a thickness of 5 to 50 nm, the low refractive index layer 14b with a thickness of 10 to 80 nm, the high refractive index layer 14a with a thickness of 20 to 200 nm, and the low refractive index layer 14b with a thickness of 50 to 200 nm. be able to.

Among the layers forming the antireflection layer 14, a low refractive index layer 14b is arranged on the antifouling layer 15 side. It is preferable that the low refractive index layer 14b of the antireflection layer 14 is in contact with the antifouling layer 15 because the antireflection performance of the antireflection layer 14 is improved.

In addition, in this embodiment, although the antireflection layer 14 was given as an example of the optical functional layer provided on the hard coat layer 12, the optical functional layer is not limited to such an example. The optical functional layer is a layer that exhibits an optical function. Optical functions are functions that control the properties of light, such as reflection, transmission, and refraction, and include, for example, antireflection functions, selective reflection functions, antiglare functions, and lens functions. In addition to the antireflection layer 14 described above, the optical functional layer may be, for example, a selective reflection layer or an antiglare layer. As the selective reflection layer and the anti-glare layer, known ones can be used. The antireflection layer, selective reflection layer, and antiglare layer may all be a single layer or a laminate of multiple layers.

[Antifouling layer 15]
The antifouling layer 15 is formed on the outermost surface of the antireflection layer 14 and prevents the antireflection layer 14 from being soiled. Furthermore, when applied to a touch panel or the like, the antifouling layer 15 suppresses wear and tear on the antireflection layer 14 due to its abrasion resistance.

The antifouling layer 15 of this embodiment is made of a vapor-deposited film in which an antifouling material is vapor-deposited. In this embodiment, the antifouling layer 15 is formed by vacuum-depositing a fluorine-based organic compound as an antifouling material on one surface of the low refractive index layer 14b constituting the antireflection layer 14. In this embodiment, since the antifouling material contains a fluorine-based organic compound, the optical laminate 10 has even better abrasion resistance and alkali resistance.

As the fluorine-based organic compound constituting the antifouling layer 15, a compound consisting of a fluorine-modified organic group and a reactive silyl group (eg, alkoxysilane) is preferably used. The fluorine-based organic compound constituting the antifouling layer 15 is, for example, a silane compound having a fluoroalkyl chain or an alkoxysilane compound having a perfluoropolyether group. Commercially available products include Optool DSX (manufactured by Daikin Corporation) and KY-100 series (manufactured by Shin-Etsu Chemical Co., Ltd.).

By using an alkoxysilane compound having a perfluoropolyether group as the fluorine-based organic compound constituting the antifouling layer 15, the contact angle of the antifouling layer 15 with water can be 110 degrees or more, and water repellency and It becomes possible to improve stain resistance.

As the fluorine-based organic compound constituting the antifouling layer 15, a compound consisting of a fluorine-modified organic group and a reactive silyl group (for example, alkoxysilane) is used, and the antireflection layer 14 in contact with the antifouling layer 15 has a low refractive index. When the layer 14b is made of SiO ₂ , a siloxane bond is formed between the silanol group, which is the skeleton of the fluorine-based organic compound, and SiO ₂ . Therefore, the adhesion between the antireflection layer 14 and the antifouling layer 15 becomes good, which is preferable.

The optical thickness of the antifouling layer 15 may be in the range of 1 nm or more and 20 nm or less, preferably in the range of 3 nm or more and 10 nm or less. When the thickness of the antifouling layer 15 is 1 nm or more, sufficient abrasion resistance can be ensured when the optical laminate 10 is applied to a touch panel or the like. Moreover, when the thickness of the antifouling layer 15 is 20 nm or less, the time required for vapor deposition is short, and it can be manufactured efficiently.

The antifouling layer 15 contains a light stabilizer, an ultraviolet absorber, a coloring agent, an antistatic agent, a lubricant, a leveling agent, an antifoaming agent, an antioxidant, a flame retardant, an infrared absorber, a surfactant, etc., as necessary. It may contain additives.

The antifouling layer 15 formed by vapor deposition is strongly bonded to the antireflection layer 14 and is dense with few voids. As a result, the antifouling layer 15 of this embodiment exhibits characteristics different from antifouling layers formed by conventional methods such as applying an antifouling material.

[2. Uneven structure 30 of hard coat layer 12]
Next, the uneven structure of the hard coat layer 12 according to this embodiment will be described with reference to FIGS. 1 to 4.

FIG. 2 is a cross-sectional view showing an example of the hard coat layer 12 according to this embodiment. As shown in FIG. 2, an uneven structure 30 is formed on the surface of the hard coat layer 12 on the adhesive layer 13 side according to the present embodiment. The uneven structure 30 includes a plurality of convex portions 32 and a plurality of concave portions 34. The top portions 32a of the plurality of convex portions 32 constituting the uneven structure 30 of the hard coat layer 12 have substantially the same height, and each of the top portions 32a has a substantially flat surface. Furthermore, the plurality of recesses 34 forming the uneven structure 30 of the hard coat layer 12 do not penetrate the hard coat layer 12 . That is, the bottom portion 34a of the recess 34 of the hard coat layer 12 does not contact the surface of the transparent base material 11.

Further, as described above, the thickness of the adhesive layer 13 (for example, about 0.005 μm), the thickness of the antireflection layer 14 (for example, about 0.2 μm), and the thickness of the antifouling layer 15 (for example, about 0.005 μm) The thickness of the hard coat layer 12 is much thinner than the thickness of the hard coat layer 12 (eg, 5 to 10 μm). Therefore, the adhesion layer 13, the antireflection layer 14, and the antifouling layer 15 are formed to follow the uneven structure 30 of the hard coat layer 12.

Therefore, as shown in FIG. 1, the surface of the adhesive layer 13 has an uneven surface 40 that follows the shape of the uneven structure 30 of the hard coat layer 12. Therefore, like the tops 32a of the projections 32 of the hard coat layer 12, the tops of the plurality of projections constituting the uneven surface 40 of the adhesive layer 13 have substantially the same height, and , each of the tops has a substantially flat surface.

Similarly, the surface of the antireflection layer 14, that is, the surface of the high refractive index layer 14a and the surface of the low refractive index layer 14b, form uneven surfaces 50a and 50b that follow the shape of the uneven structure 30 of the hard coat layer 12. There is. Therefore, the tops of the plurality of protrusions forming the uneven surface 50a of the high refractive index layer 14a and the tops of the plurality of protrusions forming the uneven surface 50b of the low refractive index layer 14b are the same as those of the hard coat layer 12. Like the tops 32a of portion 32, they have substantially the same height as each other, and each of the tops has a substantially flat surface.

Further, the surface of the antifouling layer 15 , that is, the outermost surface of the optical laminate 10 has an uneven surface 60 that follows the shape of the uneven structure 30 of the hard coat layer 12 . Therefore, the uneven surface 60 formed on the outermost surface of the optical laminate 10 is composed of a plurality of convex portions 62 and a plurality of concave portions 64. Therefore, the plurality of convex portions 62 forming the uneven surface 60 have the same shape as the plurality of convex portions 32 of the hard coat layer 12. That is, the tops 62a of the plurality of projections 62 constituting the uneven surface 60 have substantially the same height as the tops 32a of the projections 32 of the hard coat layer 12, and the tops 62a each has a substantially planar surface. Further, the plurality of recesses 64 forming the uneven surface 60 have the same shape as the plurality of recesses 34 of the hard coat layer 12 .

FIG. 3 is a diagram showing a 3D image of an example of the optical laminate 10 according to this embodiment. FIG. 4 is a diagram showing the cross-sectional roughness of an example of the optical laminate 10 according to this embodiment.

As shown in FIG. 3, the outermost surface of the optical laminate 10 is an uneven surface 60 composed of a plurality of convex portions 62 and a plurality of concave portions 64. In this uneven surface 60, the plurality of convex portions 62 are formed in the shape of floating islands that are randomly distributed and arranged in the surface direction. Each of the convex portions 62 has a generally frustum shape, but the planar shape of the convex portions 62 is random. Similarly, the plurality of convex portions 32 constituting the concavo-convex structure 30 of the hard coat layer 12 are also formed in the shape of floating islands that are randomly distributed and arranged in the surface direction.

Further, the tops 62a of the plurality of convex portions 62 forming the uneven surface 60 of the optical laminate 10 have substantially the same height. Therefore, it can be said that the top portions 32a of the plurality of convex portions 32 constituting the uneven structure 30 of the hard coat layer 12 also have substantially the same height. Here, "substantially the same height" means, for example, as shown in FIG. This means that the optical laminate 10 has a structure capable of evenly distributing stress against a load caused by an object that comes into contact with the optical laminate 10, such as an operator's finger or a stylus pen (pointing device). When the heights of the apexes 62a of the plurality of protrusions 62 are "substantially the same height," the heights of the apexes 62a of the plurality of protrusions 62 vary (i.e., the heights of the apexes 62a of the plurality of protrusions 62 are substantially the same). The height difference) may be desirably within 0.5 μm, more preferably within 0.2 μm. Similarly, when the heights of the tops 32a of the plurality of projections 32 are "substantially the same height", the height of the tops 32a of the plurality of projections 32 (i.e., the height of the tops 32a of the plurality of projections 32) (height difference) may be desirably within 0.5 μm, more preferably within 0.2 μm.

Furthermore, it is more desirable that each of the top portions 62a of the plurality of convex portions 62 constituting the uneven surface 60 of the hard coat layer 12 has a substantially flat surface (top surface). Here, the term "substantially flat surface" includes not only the case where the top portion 62a of the convex portion 62 has a completely flat surface but also the case where the top portion 62a has a flat surface with fine irregularities formed thereon. The flat surface on which fine asperities are formed means, for example, a flat surface in which the height difference of the fine asperities is ±0.3 μm or less, preferably ±0.1 μm or less with respect to the reference plane of the top portion 62a. Note that the reference surface is a completely flat surface that is virtually set at a desired height position of the convex portion 62.

Similarly, it is more desirable that each of the top portions 32a of the plurality of convex portions 32 constituting the uneven structure 30 of the optical laminate 10 has a substantially flat surface (top surface). Here, the term "substantially flat surface" includes not only the case where the top portion 32a of the convex portion 32 has a completely flat surface, but also the case where the top portion 32a of the convex portion 32 has a flat surface with fine irregularities formed thereon. The flat surface on which fine asperities are formed means, for example, a flat surface in which the height difference of the fine asperities is ±0.3 μm or less, preferably ±0.1 μm or less with respect to the reference plane of the top portion 32a. Note that the reference surface is a completely flat surface that is virtually set at a desired height position of the convex portion 32.

Further, as shown in FIG. 3, in the uneven surface 60 of the optical laminate 10, the plurality of recesses 64 are randomly distributed and scattered in the surface direction. The individual recesses 64 are, for example, recesses having a random planar shape, and the depths of the bottoms 64a of the recesses 64 are also random. Similarly, the plurality of recesses 34 constituting the uneven structure 30 of the hard coat layer 12 are also randomly distributed and dotted in the surface direction, and the planar shape of each recess 34 is also random, and the bottom 34a of the recess 34 is The depth is also random.

Further, as shown in FIG. 4, on the uneven surface 60 of the optical laminate 10, the height difference between the top 62a of the convex portion 62 and the bottom 64a of the concave portion 64 is, for example, about 0.4 μm to 1 μm. . Similarly, in the concavo-convex structure 30 of the hard coat layer 12, the height difference between the top 32a of the convex portion 32 and the bottom 34a of the concave portion 34 is, for example, about 0.4 μm to 1 μm.

In this way, the hard coat layer 12 has the uneven structure 30, that is, the uneven surface 60 is formed on the outermost surface of the optical laminate 10. Thereby, the incident light is scattered on the uneven surface 60 of the optical laminate 10, so that the optical laminate 10 can exhibit anti-glare properties.

Further, the height distribution of the surface of the uneven structure 30 of the hard coat layer 12 according to the present embodiment satisfies the following formula (1).
A/1.9 < P...(1)
A: Height of the highest point on the surface of the uneven structure 30 when the height B of the lowest point on the surface of the uneven structure 30 is 0 [μm]
P: mode of the height distribution of the surface of the uneven structure 30 when the height B of the lowest point on the surface of the uneven structure 30 is set to 0 [μm]
In other words, P is the maximum point of the distribution when the height distribution of the surface of the uneven structure 30 is expressed as a histogram.

When the above formula (1) is satisfied, in the uneven structure 30 of the hard coat layer 12, the convex portions 32 having substantially flat apexes 32a are distributed more often than the convex portions having conical or dome-shaped peaks. However, the distribution area of the flat top portions 32a is wide, and the heights of the flat top portions 32a are approximately the same. Therefore, the concavo-convex structure 30 has a rough surface structure including many flat tops 32a, and has excellent scratch resistance. On the other hand, when the above formula (1) is not satisfied, that is, when A/1.9≧P, the uneven structure of the hard coat layer has a large distribution of convex portions having cone-shaped or dome-shaped peaks. Therefore, the distribution area of the flat top becomes narrower. Therefore, the uneven structure becomes a protrusion-like structure having sharp protrusions, and the scratch resistance is reduced.

As explained above, the outermost surface of the optical laminate 10 according to the present embodiment has an uneven surface 60 that follows the shape of the uneven structure 30 of the hard coat layer 12. The tops 62a of the protrusions 62 have substantially the same height, and each of the tops 62a of the plurality of protrusions 62 has a substantially flat surface.

For this reason, a protrusion structure having a dome-shaped or cone-shaped protrusion as in the prior art is hardly formed on the outermost surface of the optical laminate 10. Therefore, the surface of the optical laminate 10 according to this embodiment has a table-like rough surface structure in which the top portion 62a of the convex portion 62 is a substantially flat surface. As a result, for example, when the optical laminate 10 is installed as an anti-reflection film on a touch panel, the load applied to the surface screen by an operator's finger or a pointing device can be dispersed at the top 62a of the convex portion 62. It becomes possible. Therefore, compared to conventional optical laminates having a protrusion structure having dome-shaped or cone-shaped protrusions, the optical laminate 10 can suppress wear of the convex portions 62 and improve scratch resistance. can be improved. Thereby, it becomes possible to improve the durability of the optical laminate 10.

[3. Characteristics of optical laminate 10]
Next, the characteristics of the optical laminate 10 according to this embodiment will be explained. The optical laminate 10 according to this embodiment has, for example, the following characteristics (A) to (C).

(A) Water contact angle (WCA)
In accordance with JIS L0849, using a friction tester using steel wool, steel wool was applied to the surface of the optical laminate 10 under the conditions of load: 1 kg, contact area: 1 cm x 1 cm, and reciprocating motion: 2000 times. Let us consider the case of performing a friction test in which friction is caused by friction. In the optical laminate 10 according to the present embodiment, the contact angle of the outermost surface of the optical laminate 10 with water after this friction test is preferably 90 degrees or more.

When a protrusion-like structure having sharp protrusions is formed on the outermost surface of an optical laminate as in the prior art, the protrusions are scraped by the sliding action of the steel wool, producing chips. In this case, the friction test is continued with scraps interposed between the steel wool and the optical laminate, so that the antifouling layer as well as the antireflection layer is scraped off from the hard coat layer. In this case, since the antifouling layer is removed from the outermost surface of the optical laminate, the outermost surface of the optical laminate 10 becomes easily wetted, and the contact angle with water after the friction test becomes less than 90 degrees. In other words, when the contact angle with water after the friction test is less than 90 degrees, by performing the friction test, the antifouling layer 15 is scraped together with the convex portions 62 forming the uneven surface 60 of the optical laminate 10. It can be said that the scratch resistance is low.

On the other hand, in the optical laminate 10 according to the present embodiment, even after performing the above friction test, the contact angle of the outermost surface of the optical laminate 10 with water after friction is 90 degrees or more. It has the characteristic of being. Therefore, in the optical laminate 10 according to the present embodiment, even when the above friction test is performed, the convex portions 62 (antifouling layer 15) forming the uneven surface 60 of the optical laminate 10 are hardly scraped. As a result, in the optical laminate 10 according to this embodiment, the uneven surface 60 is hard to be damaged and has excellent scratch resistance.

(B) Surface roughness Sa
The surface roughness Sa of the uneven structure 30 of the hard coat layer 12 is preferably 50 nm or more and 300 nm or less. Note that the surface roughness Sa means the arithmetic mean height Sa (ISO25178).

If the surface roughness Sa is less than 50 nm, there is a problem that sufficient anti-glare properties cannot be exhibited, and if it exceeds 300 nm, the tops 62a of the plurality of convex portions 62 may have substantially the same height. There is a problem in that it is difficult to obtain abrasion resistance, and sufficient scratch resistance cannot be achieved. On the other hand, since the surface roughness Sa of the uneven structure of the hard coat layer 12 of the optical laminate 10 according to the present embodiment is 50 nm or more and 300 nm or less, anti-glare properties and scratch resistance can be suitably achieved. becomes possible.

(C) External haze value (Haze)
The optical laminate 10 according to the present embodiment preferably has an external haze value defined by JIS K7136 of 3% or more and 40% or less. The external haze value is a numerical representation of the proportion of the diffused light component in the total light transmittance. The external haze value is a value obtained by removing the scattering component inside the sample (optical laminate 10) from the haze value defined in JIS K7136.

If the external haze value of the optical laminate is less than 3%, there is a problem that sufficient anti-glare properties cannot be exhibited, and if it exceeds 40%, the black reproducibility and image clarity when displaying images are impaired. There is a problem that the value becomes low. On the other hand, since the optical laminate 10 according to the present embodiment has an external haze value of 3% to 40%, it is possible to suitably achieve anti-glare properties and high image display quality. .

As explained above, the hard coat layer 12 of the optical laminate 10 according to the present embodiment has a micro-order uneven structure 30. Thereby, the optical laminate 10 according to this embodiment can exhibit anti-glare properties. Further, the uneven structure 30 of the hard coat layer 12 according to the present embodiment is formed by transfer using a transfer mold described later, and is not formed by containing filler particles as in the prior art. Therefore, the top portions 32a of the plurality of convex portions 32 constituting the uneven structure 30 according to the present embodiment have substantially the same height, and each of the top portions 32a of the plurality of convex portions 32 has It has a substantially flat surface. Therefore, even on the uneven surface 60 on the outermost surface of the optical laminate 10, the apexes 62a of the plurality of protrusions 62 have substantially the same height, and the apexes 62a of the plurality of protrusions 62 have substantially the same height. Each has a substantially flat surface and does not have a sharp protrusion, so that the scratch resistance of the optical laminate 10 is improved. Therefore, the optical laminate 10 can improve scratch resistance while maintaining anti-glare properties.

[4. Manufacturing method of optical laminate 10]
FIG. 5 is a flowchart showing a method for manufacturing the optical laminate 10 according to this embodiment.

As shown in FIG. 5, the method for manufacturing the optical laminate 10 according to the present embodiment includes a hard coat layer forming step S110, an adhesion layer forming step S120, an antireflection layer forming step S130, and an antifouling layer forming step S140. including. Each step will be explained below.

[Hard coat layer forming step S110]
The hard coat layer forming step S110 is a step of providing the hard coat layer 12 on the transparent base material 11.

In this embodiment, the hard coat layer forming step S110 includes a coating step S112 and a transfer step S114. In the transfer step S114 of the hard coat layer forming step S110, the uneven structure 30 is transferred onto the surface of the hard coat layer 12 using a transfer mold. Below, first, a method for manufacturing a transfer mold according to this embodiment will be described with reference to FIG. Next, with reference to FIG. 7, the coating process S112 and the transfer process S114 will be described.

FIG. 6 is a process diagram illustrating an example of a method for manufacturing the transfer mold 150 according to this embodiment. In addition, in FIG. 6, black circles indicate the filler particles 120, and white circles indicate the solvent 112. As shown in FIG. 6, first, a resin 100 for a transfer mold is created. The resin 100 is, for example, a binder resin 110 with filler particles 120 dispersed therein. The binder resin 110 constituting the resin 100 is not particularly limited, but it is preferably transparent that transmits energy rays such as ultraviolet rays, infrared rays, and electron beams. Line-curable resins, thermoplastic resins, thermosetting resins, etc. can be used.

Energy ray-curable resins used for the binder resin 110 include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinylpyrrolidone, carboxylic acids (acrylic acid), and hydroxyls (2-hydroxyethyl acrylate). , 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate), alkyl or alicyclic monomers (isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, lauryl acrylate, stearyl acrylate, isobonyl acrylate, cyclohexyl acrylate), and other functions monomers (2-methoxyethyl acrylate, methoxyethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, N,N-dimethylaminoethyl acrylate, N,N- Dimethylaminopropylacrylamide, N,N-dimethylacrylamide, acryloylmorpholine, N-isopropylacrylamide, N,N-diethylacrylamide, N-vinylpyrrolidone, 2-(perfluorooctyl)ethyl acrylate, 3-perfluorohexyl-2 -Hydroxypropyl acrylate, 3-perfluorooctyl-2-hydroxypropyl-acrylate, 2-(perfluorodecyl)ethyl-acrylate, 2-(perfluoro-3-methylbutyl)ethyl acrylate), 2,4,6-tri Examples include bromophenol acrylate, 2,4,6-tribromophenol methacrylate, 2-(2,4,6-tribromophenoxy)ethyl acrylate), 2-ethylhexyl acrylate, and nonylphenol EO-modified acrylate.

In addition, examples of compounds that are energy ray-curable resins having two or more unsaturated bonds include trimethylolpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, and dipropylene Glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate ) acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, isocyanuric acid Tri(meth)acrylate, isocyanuric acid di(meth)acrylate, polyester tri(meth)acrylate, polyester di(meth)acrylate, bisphenol di(meth)acrylate, diglycerin tetra(meth)acrylate, adamantyl di(meth)acrylate, Isobornyl di(meth)acrylate, dicyclopentanedi(meth)acrylate, tricyclodecane di(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, polyethylene glycol (600) diacrylate, dimethylol-tricyclodecane diacrylate, bisphenol AEO modified diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, propoxylated bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, 1, 4-butanediol diacrylate, polyethylene glycol (200) diacrylate, tetraethylene glycol diacrylate, polyethylene glycol (400) diacrylate, cyclohexanedimethanol diacrylate, aliphatic urethane acrylate, polyether urethane acrylate, 2-hydroxy- 3-acryloyloxypropyl methacrylate, isocyanuric acid EO-converted triacrylate, ε-caprolactone modified tris-(2-acryloxyethyl) isocyanurate, trimethylolpropane triacrylate (TMPTA), ε-caprolactone modified tris(acryloxyethyl) Examples include polyfunctional compounds such as acrylate and tris-(2-acryloxyethyl)isocyanurate. Among them, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA) and pentaerythritol tetraacrylate (PETTA) are preferably used. Note that "(meth)acrylate" refers to methacrylate and acrylate. Furthermore, as energy ray-curable resins, those obtained by modifying the above-mentioned compounds with PO (propylene oxide), EO (ethylene oxide), CL (caprolactone), etc. can also be used.

Examples of thermoplastic resins used for the binder resin 110 include styrene resins, (meth)acrylic resins, vinyl acetate resins, vinyl ether resins, halogen-containing resins, alicyclic olefin resins, polycarbonate resins, and polyesters. Examples thereof include polyamide-based resins, polyamide-based resins, cellulose derivatives, silicone-based resins, and rubbers or elastomers. The thermoplastic resin is preferably non-crystalline and soluble in an organic solvent (particularly a common solvent capable of dissolving a plurality of polymers and curable compounds). In particular, from the viewpoint of transparency and weather resistance, styrene resins, (meth)acrylic resins, alicyclic olefin resins, polyester resins, cellulose derivatives (cellulose esters, etc.), and the like are preferred.

Examples of thermosetting resins used for the binder resin 110 include phenol resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, aminoalkyd resins, and melamine-urea cocondensation resins. Examples include resins, silicone resins, polysiloxane resins (including so-called silsesquioxanes such as cage-shaped and ladder-shaped silsesquioxanes), and the like.

Note that here, as the binder resin 110, an ultraviolet curing resin is taken as an example. Moreover, a photopolymerization initiator is blended into the ultraviolet curable resin.

As the filler particles 120 contained in the binder resin 110, known particles such as particles made of inorganic oxides such as silica (Si oxide) particles and alumina (aluminum oxide) particles, or organic particles can be used. . The average particle size of the inorganic oxide particles such as silica particles and alumina particles as the filler particles 120 is not particularly limited, but is preferably 0.5 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less. be.

Furthermore, examples of the organic particles as the filler particles 120 include acrylic resin. The particle diameter of the organic particles is not particularly limited, but is preferably 0.5 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less.

The content of the binder resin 110 in the resin 100 is adjusted to be as low as possible so that the filler particles 120 are not buried in the binder resin 110 when the resin 100 is applied to a mold base material 130, which will be described later.

Then, the created resin 100 is applied onto the surface 130a of the mold base material 130. The mold base material 130 is made of, for example, a material that can transmit ultraviolet rays. The mold base material 130 may be formed of, for example, the same organic material or inorganic material as the transparent base material 11 described above. The surface 130a of the mold base material 130 to which the resin 100 is applied is substantially flat. Here, "substantially flat" means that there is no substantial height difference over the entire surface 130a of the mold base material 130. For example, the height difference over the entire surface 130a of the mold base material 130 is It may be preferably within 0.5 μm, more preferably within 0.2 μm. Further, fine irregularities may be formed on the surface 130a of the mold base material 130. The height difference of the fine irregularities formed on the surface 130a is preferably ±0.3 μm or less, preferably ±0.1 μm or less with respect to the reference plane of the surface 130a. Note that the reference surface is a completely flat surface that is virtually set at a desired height position of the surface 130a.

Thereafter, while drying the resin 100 applied to the mold base material 130, the resin 100 is irradiated with ultraviolet rays to cure the ultraviolet curable resin as the binder resin 110 contained in the resin 100. Then, the solvent 112 contained in the resin 100 evaporates, and the binder resin 110 aggregates around the filler particles 120.

In this way, the transfer mold 150 in which the filler particles 120 covered with the binder resin 110 are scattered on the surface 130a of the mold base material 130 is manufactured. The filler particles 120 covered with the binder resin 110 form protrusions in an arbitrary shape such as a dome shape or a cone shape on the surface 130a of the mold base material 130. Hereinafter, the filler particles 120 covered with the binder resin 110 will be simply referred to as "protrusions 140." A plurality of protrusions 140 are formed on the flat surface 130a of the mold base material 130 so as to be spaced apart from each other. A flat surface 130a of the mold base material 130 is exposed between adjacent protrusions 140. In this way, a transfer mold 150 having an uneven shape 152 consisting of a plurality of convex portions 142 and a plurality of concave portions 132 is manufactured. The convex portion 142 of this uneven shape 152 is composed of the protrusion 140 described above, and the bottom of the concave portion 132 is the flat surface 130a of the mold base material 130.

[Coating process S112]
Next, with reference to FIG. 7, the coating step S112 and the transfer step S114 shown in FIG. 5 will be described. FIG. 7 is a process diagram illustrating the coating process S112 and the transfer process S114 according to the present embodiment. The coating step S112 is a step of coating the surface of the transparent base material 11 with, for example, the energy ray curable resin composition 70. The energy ray curable resin composition 70 includes an uncured energy ray curable resin, an energy ray polymerization initiator, and metal oxide fine particles.

Note that the thickness (film thickness) of the energy ray-curable resin composition 70 applied to the surface of the transparent base material 11 is greater than the height of the projections 140 (convex portions 142) of the transfer mold 150 shown in FIG. .

[Transfer step S114]
The transfer step S114 is a step of transferring the uneven shape 152 of the transfer mold 150 onto the energy beam curable resin composition 70. Specifically, first, the uneven shape 152 of the transfer mold 150 is pressed against the energy ray curable resin composition 70. Then, energy rays are irradiated to cure the energy ray curable resin composition 70. Note that, as described above, the transfer mold 150 has transparency that allows energy rays to pass therethrough. Therefore, by irradiating the energy beam while pressing the uneven shape 152 of the transfer mold 150 onto the energy ray curable resin composition 70, the uneven shape 152 of the transfer mold 150 is transferred to the energy ray curable resin composition 70. At the same time, the energy ray curable resin composition 70 can be cured.

Then, when the transfer mold 150 is peeled off from the cured energy ray curable resin composition 70, the hard coat layer 12 having the uneven structure 30 is formed. The uneven structure 30 of the hard coat layer 12 has an inverted shape of the uneven shape 152 of the transfer mold 150. Specifically, the convex portions 32 constituting the concavo-convex structure 30 of the hard coat layer 12 have a shape corresponding to the concave portions 132 of the concavo-convex shape 152 of the transfer mold 150. Further, the recesses 34 forming the uneven structure 30 of the hard coat layer 12 have a shape corresponding to the projections 142 (protrusions 140) of the uneven structure 152 of the transfer mold 150.

Further, as described above, the surface 130a of the mold base material 130 of the transfer mold 150 is substantially flat. Therefore, by transferring the uneven shape 152 of the transfer mold 150, the tops 32a of the plurality of protrusions 32 forming the uneven structure 30 of the hard coat layer 12 also have substantially the same height. . Further, as described above, the height difference of the fine irregularities on the surface 130a of the mold base material 130 of the transfer mold 150 is ±0.3 μm or less with respect to the reference plane of the surface 130a. Therefore, by transferring the uneven shape 152 of the transfer mold 150, each of the top portions 32a of the plurality of convex portions 32 forming the uneven structure 30 of the hard coat layer 12 also has a substantially flat surface.

Note that the uneven shape 152 of the transfer mold 150 is adjusted according to the desired shape of the uneven structure 30 of the hard coat layer 12. Specifically, when manufacturing the transfer mold 150, the particle size of the filler particles 120 contained in the resin 100, the content of the filler particles 120, etc. are adjusted depending on the desired shape of the uneven structure 30. . For example, if it is desired to increase the size of the convex portions 32 of the concavo-convex structure 30 of the hard coat layer 12, the content of the filler particles 120 may be reduced. If it is desired to make the convex portions 32 of the concavo-convex structure 30 of the hard coat layer 12 small, the content of filler particles 120 may be increased. Furthermore, if it is desired to increase the height of the convex portions 32 of the uneven structure 30 of the hard coat layer 12 or the depth of the concave portions 34, the particle size of the filler particles 120 may be increased. If it is desired to reduce the height of the convex portions 32 or the depth of the concave portions 34 of the hard coat layer 12, the particle size of the filler particles 120 may be reduced.

In addition, the surface of the transfer mold 150 (the filler particles 120 covered with the binder resin 110 and the surface 130a between the filler particles 120) may be provided with a shape that reduces peeling of the transfer mold 150 or has a surface shape as necessary. An additional layer may be provided for the purpose of protecting (not shown). Examples of the layers include, in order from the binder resin 110 side, an inorganic layer and an antifouling layer. The antifouling layer improves releasability when peeling off after transferring the shape to the energy ray curable resin composition 70 (hard coat layer 12). Further, the inorganic layer has the effect of more firmly bonding the antifouling layer to the transfer mold 150. Here, the inorganic layer can be provided by sputtering or vapor deposition, and the number of layers can be set arbitrarily. The antifouling layer may be made of any material as long as it improves releasability from the hard coat layer 12, and examples include silane compounds having a fluorine-containing group such as a fluoroalkyl group. Methods for forming the antifouling layer include coating and drying, vapor deposition, and the like. That is, if a desired shape can be transferred to the hard coat layer 12, another optical laminate having a shape corresponding to the desired shape can be used as the transfer mold 150.

Note that the hard coat layer forming step S110 is not limited to the above, and may be performed by any known method. For example, it may be carried out by shape transfer using a rigid roll provided with a desired shape, injection molding, etc. using a stamper provided with a desired shape, or the like.

[Adhesion layer forming step S120]
Returning to FIG. 5, the adhesion layer forming step S120 is a step of forming the adhesion layer 13 on the surface of the hard coat layer 12.

[Anti-reflection layer forming step S130]
The antireflection layer forming step S130 is a step of forming the antireflection layer 14 on the surface of the adhesive layer 13. For example, in the antireflection layer forming step S130, high refractive index layers 14a and low refractive index layers 14b are alternately formed.

In this embodiment, the adhesion layer forming step S120 and the antireflection layer forming step S130 are performed by sputtering. In this embodiment, it is preferable to use magnetron sputtering as the sputtering method from the viewpoint of increasing the film formation rate. Note that the sputtering method is not limited to the magnetron sputtering method, and a two-pole sputtering method that uses plasma generated by direct current glow discharge or high frequency, a three-pole sputtering method that uses a hot cathode, etc. may be used. .

[Antifouling layer forming step S140]
The antifouling layer forming step S140 is a step of forming the antifouling layer 15 on the surface of the antireflection layer 14. In this embodiment, the antifouling layer forming step S140 is performed by, for example, a vacuum deposition method.

By the above manufacturing method, an optical laminate 10 including a transparent base material 11, a hard coat layer 12, an adhesion layer 13, an antireflection layer 14, and an antifouling layer 15 is obtained.

In the optical laminate 10 according to the present embodiment, various coatings may be applied to the second surface of both surfaces of the transparent base material 11, which is opposite to the first surface on which the hard coat layer 12 and the like are laminated. layers may be provided. For example, an adhesive layer used for adhesion to other members may be provided. Further, another optical film may be provided via this adhesive layer. Examples of other optical films include films that function as polarizing films (polarizing plates), retardation compensation films, 1/2 wavelength plates, and 1/4 wavelength plates.

Further, the second surface of the transparent base material 11 may be provided with functions such as antireflection, selective reflection, antiglare, polarization, phase difference compensation, viewing angle compensation or expansion, light guide, diffusion, brightness improvement, hue adjustment, or conductivity. A layer containing the material may be formed directly.

The optical laminate 10 according to this embodiment can be applied to optical members such as polarizing plates and image display devices. For example, the optical laminate 10 may be provided on a display screen of an image display device such as a liquid crystal display panel or an organic EL display panel. As a result, high scratch resistance can be imparted to, for example, a touch panel display section of a smartphone or an operating device, and an image display device with excellent durability and suitable for actual use can be realized.

Furthermore, the article to which the optical laminate 10 is applied is not limited to the example of the image display device described above. For example, window glass, goggles, light-receiving surfaces of solar cells, smartphone screens, personal computer displays, information input terminals, tablet terminals, AR (augmented reality) devices, VR (virtual reality) devices, electronic display boards, glass tables. The optical laminate 10 can be applied to various articles such as surfaces, game machines, operation support devices such as airplanes and trains, navigation systems, instrument panels, and surfaces of optical sensors.

Examples and comparative examples of the present invention will be specifically described below. Note that the examples shown below are merely examples, and the optical laminate and the method for manufacturing the optical laminate according to the present invention are not limited to the examples below.

As samples of optical laminates, samples A to E and sample K were prepared as comparative examples, and samples F to J were prepared as examples. Furthermore, in preparing Samples A to J, Resin A and Resin B were prepared. The composition of Resin A is shown in Table 1 below. The composition of resin B is shown in Table 2 below. In addition, the unit of the compounding ratio in Tables 1 and 2 is weight %.

[Sample A: Comparative example]
As the transparent base material 11, a TAC film (ZRD60SL manufactured by Fujifilm) was used. A mixture containing resin A: 7.3% by weight, butyl acetate: 91.2% by weight, leveling agent BYK-377: 0.75% by weight, and Sekisui Plastics organic filler SSX-101: 0.75% by weight. The resin was applied onto the transparent substrate 11 by spin coating. The spin coating conditions were 3500 rpm. Thereafter, the transparent base material 11 coated with the mixed resin was dried for 1 minute in an environment of 80° C., and then UV irradiation was performed to harden the mixed resin to form a hard coat layer on the transparent base material 11. After forming a metal oxide layer on the hard coat layer using a sputtering device, an antifouling layer was formed using a vapor deposition device to obtain sample A.

In sample A according to the comparative example, it was confirmed that a plurality of protrusion-like structures having different heights were scattered. Further, in Sample A according to the comparative example, more concave portions than convex portions were formed.

[Sample B: Comparative example]
Sample A except that resin A: 9.8% by weight, butyl acetate: 88% by weight, leveling agent BYK-377: 1.2% by weight, and Sekisui Plastics organic filler BMSA-18GN: 1.0% by weight. Sample B was obtained in the same manner.

In sample B according to the comparative example, it was confirmed that a plurality of protrusion structures having different heights were scattered like floating islands. Further, Sample B according to the comparative example had more concave portions than convex portions.

[Sample C: Comparative example]
Resin A: 11.1% by weight, butyl acetate: 86.5% by weight, leveling agent BYK-377: 1.3% by weight, organic filler manufactured by Sekisui Kasei BMSA-18GN: 1.1% by weight. Sample C was obtained in the same manner as A.

In sample C according to the comparative example, it was confirmed that a plurality of protrusion-like structures having different heights were scattered like floating islands. Further, in Sample B according to the comparative example, the convex portions and the concave portions were formed to be approximately equal.

[Sample D: Comparative example]
Except that the transparent base material 11 and the hard coat layer were commercially available film A comprising a cured product of an acrylic resin composition containing filler particles with a particle diameter of 2 μm on a TAC base material with a thickness of 60 μm. , Sample D was obtained in the same manner as Sample A.

In sample D according to the comparative example, it was confirmed that a plurality of protrusion-like structures having different heights were scattered.

[Sample E: Comparative example]
Except that the transparent base material 11 and the hard coat layer were commercially available film B comprising a cured product of an acrylic resin composition containing filler particles with a particle diameter of 5 μm on a TAC base material with a thickness of 60 μm. , Sample E was obtained in the same manner as Sample A.

In sample E according to the comparative example, it was confirmed that a plurality of protrusion structures having different heights were scattered.

[Sample F: Example]
As the transparent base material 11, a TAC film (ZRD60SL manufactured by Fujifilm) was used. Resin B was coated onto the transparent base material 11 using a known method so as to have a film thickness of 10 μm. Thereafter, the transparent base material 11 coated with resin B was dried for 1 minute in an environment of 80° C., and sample A was then laminated as a transfer mold 150. After curing resin B by UV irradiation, sample A was peeled off from the transfer mold 150 to form a hard coat layer 12 on the transparent base material 11. Subsequently, a metal oxide layer (adhesive layer 13 and antireflection layer 14) is formed on the hard coat layer 12 using a sputtering device, and then an antifouling layer 15 is formed using a vapor deposition device. I got it.

In sample F according to the example, it was confirmed that a plurality of protrusions 62 having substantially the same height were formed in a floating island shape. Furthermore, in Sample F, it was confirmed that each of the top portions 62a of the convex portions 62 had a substantially flat surface. Furthermore, in sample F according to the example, more convex portions 62 than concave portions 64 were formed.

[Sample G]
Sample G was obtained in the same manner as Sample F except that Sample B was used as the transfer mold 150 to be laminated.

In sample G according to the example, it was confirmed that a plurality of protrusions 62 having substantially the same height were formed in a floating island shape. Furthermore, in Sample G, it was confirmed that each of the top portions 62a of the convex portions 62 had a substantially flat surface. Furthermore, in sample G according to the example, more convex portions 62 than concave portions 64 were formed.

[Sample H]
Sample H was obtained in the same manner as Sample F except that Sample C was used as the transfer mold 150 to be laminated.

In sample H according to the example, it was confirmed that a plurality of protrusions 62 having substantially the same height were formed in a floating island shape. Furthermore, in Sample H, it was confirmed that each of the top portions 62a of the convex portions 62 had a substantially flat surface. Furthermore, in sample H according to the example, the convex portions 62 and the concave portions 64 were formed approximately equally.

[Sample I]
Sample I was obtained in the same manner as Sample F except that Sample D was used as the transfer mold 150 to be laminated.

It was confirmed that in Sample I according to the example, a plurality of protrusions 62 having substantially the same height were formed in a floating island shape.

[Sample J]
Sample J was obtained in the same manner as Sample F except that Sample E was used as the transfer mold 150 to be laminated.

It was confirmed that in sample J according to the example, a plurality of protrusions 62 having substantially the same height were formed in a floating island shape.

[Sample K: Comparative example]
As the transparent base material 11, a TAC film (ZRD60SL manufactured by Fujifilm) was used. Resin B was coated onto the transparent base material 11 using a known method so as to have a film thickness of 10 μm. Thereafter, the transparent base material 11 coated with resin B was dried for 1 minute in an environment of 80° C., and sample J was then laminated as a transfer mold 150. After curing resin B by UV irradiation, sample J was peeled off from transfer mold 150 to form a hard coat layer on transparent base material 11. Subsequently, a metal oxide layer was formed on the hard coat layer using a sputtering device, and then an antifouling layer was formed using a vapor deposition device to obtain sample K.

In sample K according to the comparative example, it was confirmed that a plurality of protrusion-like structures having different heights were scattered.

[Shape evaluation]
The surface shapes of samples A to K were imaged using a scanning white interference microscope VS1800 manufactured by Hitachi High-Technologies. The objective lens used during imaging was 20x. After the image was captured, a csv file in which measurement data of the height of each pixel of the captured image was recorded was obtained. Then, after detecting the lowest point of height from the csv file, an offset was applied to all data so that the lowest point became 0 (zero). Then, the highest point of height was detected and a histogram was created. Then, based on the histogram, the values of the highest point height A [μm] and the mode P [μm] shown in the above formula (1) were obtained.

FIG. 8 is a diagram showing a histogram of sample A according to a comparative example. FIG. 9 is a diagram showing a histogram of sample B according to a comparative example. FIG. 10 is a diagram showing a histogram of sample C according to a comparative example. FIG. 11 is a diagram showing a histogram of sample D according to a comparative example. FIG. 12 is a diagram showing a histogram of sample E according to a comparative example. FIG. 13 is a diagram showing a histogram of sample K according to a comparative example. Note that in FIGS. 8 to 13, the broken line indicates the value of "A/1.9".

As shown in FIG. 8, the highest point height A of sample A according to the comparative example was 3.41 μm, and the mode P was 1.76 μm . Therefore, for sample A, A/1.9>P. That is, in the histogram shown in FIG. 8, the mode P [μm] is located to the left of the broken line indicating A/1.9.

As shown in FIG. 9, the height A of the highest point of sample B according to the comparative example was 2.21 μm, and the mode P was 0.43 μm . Therefore, for sample B, A/1.9>P. That is, in the histogram shown in FIG. 9, the mode P [μm] is located to the left of the broken line indicating A/1.9.

As shown in FIG. 10, the height A of the highest point of sample C according to the comparative example was 1.71 μm, and the mode P was 0.30 μm . Therefore, for sample C, A/1.9>P. That is, in the histogram shown in FIG. 10, the mode P [μm] is located to the left of the broken line indicating A/1.9.

As shown in FIG. 11, the height A of the highest point of sample D according to the comparative example was 1.29 μm, and the mode P was 0.30 μm . Therefore, for sample D, A/1.9>P. That is, in the histogram shown in FIG. 11, the mode P [μm] is located to the left of the broken line indicating A/1.9.

As shown in FIG. 12, the height A of the highest point of sample E according to the comparative example was 2.51 μm, and the mode P was 0.49 μm . Therefore, for sample E, A/1.9>P. That is, in the histogram shown in FIG. 12, the mode P 2 [μm] is located to the left of the broken line indicating A/1.9.

As shown in FIG. 13, the height A of the highest point of sample K according to the comparative example was 1.90 μm, and the mode P was 0.59 μm . Therefore, for sample K, A/1.9>P. That is, in the histogram shown in FIG. 13, the mode P [μm] is located to the left of the broken line indicating A/1.9.

FIG. 14 is a diagram showing a histogram of sample F according to the example. FIG. 15 is a diagram showing a histogram of sample G according to the example. FIG. 16 is a diagram showing a histogram of sample H according to the example. FIG. 17 is a diagram showing a histogram of sample I according to the example. FIG. 18 is a diagram showing a histogram of sample J according to the example. Note that in FIGS. 14 to 18, the broken line indicates the value of "A/1.9".

As shown in FIG. 14, the highest point height A of sample F according to the example was 3.26 μm, and the mode P was 2.62 μm . Therefore, for sample F, A/1.9<P. That is, in the histogram shown in FIG. 14, the mode P [μm] is located on the right side of the broken line indicating A/1.9.

As shown in FIG. 15, the height A of the highest point of sample G according to the example was 2.66 μm, and the mode P was 2.21 μm . Therefore, for sample G, A/1.9<P. That is, in the histogram shown in FIG. 15, the mode P [μm] is located on the right side of the broken line indicating A/1.9.

As shown in FIG. 16, the height A of the highest point of sample H according to the example was 1.67 μm, and the mode P was 1.17 μm . Therefore, for sample H, A/1.9<P. That is, in the histogram shown in FIG. 16, the mode P [μm] is located on the right side of the broken line indicating A/1.9.

As shown in FIG. 17, the height A of the highest point of sample I according to the example was 1.22 μm, and the mode P was 0.87 μm . Therefore, for sample I, A/1.9<P. That is, in the histogram shown in FIG. 17, the mode P [μm] is located on the right side of the broken line indicating A/1.9.

As shown in FIG. 18, the height A of the highest point of sample J according to the example was 2.57 μm, and the mode P was 2.08 μm . Therefore, for sample J, A/1.9<P. That is, in the histogram shown in FIG. 17, the mode P [μm] is located on the right side of the broken line indicating A/1.9.

From the above results, it was confirmed that Sample F, Sample G, Sample H, Sample I, and Sample J according to Examples satisfy the above formula (1). That is, in Samples F to J according to Examples, on the uneven surface 60 of the outermost surface of the optical laminate 10 (the surface of the antifouling layer 15), the tops 62a of the plurality of convex portions 62 are substantially mutually It was confirmed that they have the same height, and that each of the tops 62a of the plurality of convex portions 62 has a substantially flat surface, and that the uneven surface 60 has a rough structure with excellent scratch resistance. Ta.

On the other hand, it was confirmed that Sample A, Sample B, Sample C, Sample D, Sample E, and Sample K according to the comparative example did not satisfy the above formula (1). In other words, in samples A to E and sample K according to comparative examples, the height of each of the tops of the plurality of convex portions on the uneven surface of the outermost surface (in the direction of the antifouling layer) of the optical laminate is substantially It was confirmed that the uneven surface had a protrusion-like structure including many sharp protrusions (points) with different heights, and the scratch resistance was poor.

[Evaluation of scratch resistance]
Samples A to E and Sample K according to Comparative Examples, and Samples F to J according to Examples were each laminated to a 100 mm x 50 mm blue plate glass using transparent PSA (TD06A) manufactured by Tomegawa Paper Mills. A test piece was prepared. Subsequently, using a friction tester type I based on JIS L0849, the friction body was horizontally reciprocated along the surface of each test piece. Steel wool (#0000, manufactured by Bonstar Co., Ltd.) was used as the friction body. The conditions for this friction test were a load of 1 kg, a contact area of 1 cm x 1 cm, a sliding distance of 50 mm, and a sliding speed of 60 reciprocations/min. Further, the number of horizontal reciprocations was set to 2000 times. Thereafter, the contact angle of pure water was measured.

The pure water contact angle (WCA) was measured by the ellipse fitting method using a fully automatic contact angle meter DM-700 (manufactured by Kyowa Interface Science Co., Ltd.) under the following conditions. Distilled water was placed in a glass syringe, a stainless steel needle was attached to the tip of the syringe, and pure water was dripped onto each test piece.
Dropped amount of pure water: 2.0μL
Measurement temperature: 25℃
The contact angle after 4 seconds had elapsed after dropping pure water was measured at six arbitrary locations on the surface of the test piece, and the average value was taken as the pure water contact angle (WCA).

[Optical evaluation]
The external haze values of Samples A to E and Sample K according to Comparative Examples and Samples F to J according to Examples were measured. The external haze value was measured using Nippon Denshoku NDH-7000 based on JIS K7136.

The results measured for Samples F to J according to the above Examples are summarized in Table 31 below. In addition, the results measured for Samples A to E and Sample K according to Comparative Examples are summarized in Table 4 below.

Referring to the results in Tables 3 and 4, the external haze values [%] of Samples F to J according to Examples are 3% or more and 40%, similar to Samples A to E and Sample K according to Comparative Examples. It turns out that the following is true. Therefore, it was confirmed that Samples F to J according to Examples have external haze values [%] comparable to Samples A to E and Sample K according to Comparative Examples.

Furthermore, referring to the results in Tables 3 and 4, the surface roughness Sa [nm] of Samples F to J according to Examples is 60 nm or more, similar to Samples A to E and Sample K according to Comparative Examples. , 250 nm or less. Therefore, it was confirmed that Samples F to J according to Examples had the same surface roughness Sa as Samples A to E and Sample K according to Comparative Examples.

From the above measurement results of external haze value [%] and surface roughness Sa [nm], Samples F to J according to Examples have anti-glare properties comparable to Samples A to E and Sample K according to Comparative Examples. It turns out that it has sex.

Further, referring to the results in Table 3, it was confirmed that Samples F to J according to Examples satisfied the above formula (1). That is, in Samples F to J according to Examples, the tops 62a of the plurality of convex portions 62 forming the uneven surface 60 of the outermost surface (antifouling layer 15) have substantially the same height. However, it was also confirmed that each of the top portions 62a of the plurality of convex portions 62 had a substantially flat surface.

On the other hand, referring to the results in Table 4, it was confirmed that Samples A to E and Sample K according to Comparative Examples did not satisfy the above formula (1). In other words, in Samples A to E and Sample K according to comparative examples, the heights of the tops of the plurality of convex portions forming the uneven surface of the outermost surface (antifouling layer) are not substantially the same. It was confirmed that the top part was not a flat surface, that is, it had a protrusion-like structure having a plurality of protrusions having mutually different heights.

Further, referring to the results in Table 3, it was confirmed that the contact angle of the outermost surface of Samples F to J according to the example after performing the friction test was 90 degrees or more with respect to water. . As a result, it was found that Samples F to J according to Examples had high scratch resistance.

On the other hand, referring to the results in Table 4, it can be seen that the contact angle of the outermost surface of Sample A to Sample E and Sample K according to the comparative example after performing the friction test was 58 degrees or less with respect to water. confirmed.

In other words, the contact angles of the outermost surfaces of Samples F to J according to Examples after performing the friction test with water are 1.5% of the contact angles of Samples A to E and Sample K according to Comparative Examples. It was 57 times to 1.96 times.

As explained above, according to the present embodiment, the anti-glare property is comparable to that of the conventional technology in which a concavo-convex structure is formed using filler particles of about 1 to 10 μm, while the scratch resistance is significantly improved compared to the conventional technology. It becomes possible to provide an improved optical laminate 10, a polarizing plate, and an image display device including the same.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these embodiments. It is clear that those skilled in the art can come up with various changes and modifications within the scope of the claims, and it is understood that these naturally fall within the technical scope of the present invention. be done.

In addition, in the said embodiment, the case where the optical laminated body 10 is provided with the adhesive layer 13, the antireflection layer 14, and the antifouling layer 15 was mentioned as an example. However, the optical laminate 10 only needs to include at least one metal oxide layer made of a metal oxide on the hard coat layer 12. The metal oxide layer may be any of the various optical functional layers described above. For example, the optical laminate 10 may include a transparent base material 11, a hard coat layer 12, an adhesive layer 13, an optical functional layer, and an antifouling layer 15. Further, either one or both of the adhesive layer 13 and the antifouling layer 15 may not be provided.

10 Optical laminate 11 Transparent base material 12 Hard coat layer 13 Adhesion layer (metal oxide layer)
14 Antireflection layer (metal oxide layer)
14a High refractive index layer 14b Low refractive index layer 150 Transfer mold 30 Uneven structure 32 Convex portion 32a Top portion 34 Concave portion 60 Uneven surface 62 Convex portion 62a Top portion 64 Concave portion

Claims (15)

a transparent base material,
at least one or more hard coat layer formed on the transparent base material and made of a resin composition;
at least one metal oxide layer formed on the hard coat layer and made of a metal oxide;
at least one antifouling layer provided on the metal oxide layer and containing a fluorine-based organic compound;
Equipped with
An uneven structure is randomly formed on the surface of the hard coat layer on the metal oxide layer side,
An optical laminate in which the height distribution of the surface of the uneven structure satisfies the following formula (1).
A/1.9 < P...(1)
A: Height of the highest point on the surface of the uneven structure when the height B of the lowest point on the surface of the uneven structure is 0 [μm]
P: the mode of the height distribution of the surface of the uneven structure when the height B of the lowest point on the surface of the uneven structure is 0 [μm] The optical laminate according to claim 1, wherein a difference in height between the tops of the plurality of convex portions constituting the uneven structure of the hard coat layer is within 0.5 μm . The outermost surface of the optical laminate has an uneven surface that follows the shape of the uneven structure of the hard coat layer,
The optical laminate according to claim 2, wherein a height difference between the tops of the plurality of convex portions forming the uneven surface is within 0.5 μm . According to any one of claims 1 to 3 , the height difference of the uneven structure of the hard coat layer is ±0.3 μm or less with respect to a reference plane of the top of the convex portion forming the uneven structure. The optical laminate described above. The outermost surface of the optical laminate has an uneven surface that follows the shape of the uneven structure of the hard coat layer,
5. The optical laminate according to claim 4 , wherein the height difference of the uneven structure forming the uneven surface is ±0.3 μm or less with respect to a reference plane of the top of the convex portion forming the uneven structure. The optical laminate according to any one of claims 1 to 3, wherein the surface roughness Sa of the uneven structure of the hard coat layer is 50 nm or more and 300 nm or less. Using a friction tester using steel wool, the steel wool was rubbed against the surface of the optical laminate under the conditions of load: 1 kg, contact area: 1 cm x 1 cm, and reciprocating motion: 2000 times. The optical laminate according to any one of claims 1 to 3, wherein the outermost surface of the optical laminate has a contact angle with water of 90 degrees or more. The optical laminate according to any one of claims 1 to 3, having an external haze value defined by JIS K7136 of 3% or more and 40% or less. The optical laminate according to any one of claims 1 to 3, wherein the hard coat layer contains metal oxide fine particles having an average particle size of 20 nm or more and 100 nm or less. The optical laminate according to any one of claims 1 to 3, wherein the hard coat layer does not contain filler particles having an average particle size of 1 μm or more. The metal oxide layer includes an antireflection layer,
The antireflection layer is composed of a laminate in which low refractive index layers and high refractive index layers having a higher refractive index than the low refractive index layers are alternately laminated,
The optical laminate according to any one of claims 1 to 3, wherein the optical laminate is an antireflection film having an antiglare function and an antireflection function. The optical laminate according to claim 11, wherein the metal oxide layer includes an adhesion layer provided between the hard coat layer and the antireflection layer. A polarizing plate comprising the optical laminate according to any one of claims 1 to 3. An image display device comprising the optical laminate according to claim 1. A method for producing an optical laminate according to any one of claims 1 to 3, comprising:
providing a hard coat layer made of a resin composition on a transparent substrate;
providing at least one metal oxide layer on the hard coat layer;
providing an antifouling layer on the metal oxide layer;
including;
The step of providing the hard coat layer includes:
applying the resin composition on the surface of the transparent base material;
a step of transferring an uneven shape of a transfer mold having a random uneven shape to the resin composition;
A method for manufacturing an optical laminate, comprising:

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