Optical laminate and article provided with same

Abstract

An optical laminate 102 comprises in the following order: a transparent base material 11; a hard coat layer 12; an adhesion layer 13 which is composed of a sputtered film; an optical function layer 14 in which high refractive index layers that are each composed of a sputtered film and low refractive index layers that have a refractive index lower than the high refractive index layers are alternately laminated; and an antifouling layer 15. The hard coat layer 12 contains silica particles (A) that have an average particle diameter of 65 nm or more, and the optical laminate satisfies the condition 1 and the condition 2 described below. Condition 1: The ratio ((A) / (B)) of the Martens hardness (A) on the optical laminate antifouling layer side to the Martens hardness (B) on the hard coat layer side of a laminate having only the transparent base material and the hard coat layer is 3.65 or less. Condition 2: Using a friction testing machine that uses steel wool in accordance with JIS L0849, the difference in contact angle with respect to water before friction and after friction, in which the steel wool is subjected to 200 horizontal reciprocating motions, is 20° or less.

Description

Optical laminate and article containing the same

[0001] The present invention relates to an optical laminate and an article equipped therewith, and more particularly to an optical laminate used as an anti-reflective film suitable for displays that are bent, such as flexible displays, and an article equipped therewith. This application claims priority to Japanese Patent Application No. 2024-188734, filed in Japan on October 28, 2024, the contents of which are incorporated herein by reference.

[0002] In recent years, foldable displays have been introduced in mobile communication devices such as smartphones and information equipment such as notebook PCs. These displays also sometimes utilize optical laminates, such as anti-reflective films, to reduce surface reflection. However, optical laminates used in foldable displays require greater durability against bending compared to non-foldable displays.

[0003] For example, Patent Document 1 proposes improving the flexibility of a hard coat film having an optical functional layer consisting of a hard coat layer and a sputtered film by setting the ratio of the thickness of the hard coat layer to the optical functional layer to a predetermined range.

[0004] Furthermore, Patent Document 2 describes how the flexibility can be improved by making the hard coat layer and anti-reflective layer from resin.

[0005] Japanese Patent Publication No. 2022-185597 Japanese Patent Publication No. 2020-74019

[0006] However, while Patent Document 1 can improve the abrasion resistance and flexibility of the hard coat film, it does not evaluate scratch resistance, leaving room for improvement. Similarly, while Patent Document 2 can improve the flexibility of the anti-reflective film, the anti-reflective layer is made of resin, resulting in inferior scratch resistance.

[0007] This invention has been made in view of the above problems, and aims to provide an optical laminate and an article equipped therewith that can achieve excellent scratch resistance and further improve flexibility.

[0008] To solve the above problems, this invention proposes the following means: [1] An optical laminate having a transparent substrate, a hard coat layer, an optical functional layer including an anti-reflective layer, and an anti-fouling layer in this order, wherein the hard coat layer contains silica particles (A) with an average particle diameter of 65 nm or more, and satisfies the following conditions 1 and 2. Condition 1: The ratio ((A) / (B)) of the Martens hardness (A) measured from the anti-fouling layer side of the optical laminate to the Martens hardness (B) measured from the hard coat layer side of a laminate having only the transparent substrate and the hard coat layer is 3.65 or less. Condition 2: Using a friction tester with steel wool conforming to JIS L0849, the difference in contact angle with water before friction and after friction in which the steel wool is moved horizontally back and forth 200 times is 20° or less.

[0009] [2] The optical laminate according to [1], wherein the silica particles (A) are surface-modified with functional groups derived from a silane compound.

[0010] [3] The optical laminate according to [1], wherein the hard coat layer further contains silica particles (B) with an average particle diameter of 55 nm or less.

[0011] [4] The optical laminate according to [3], wherein the silica particles (B) are surface-modified with functional groups derived from a silane compound.

[0012] [5] The optical laminate according to [2] or [4], wherein the silane compound is one or more selected from vinyl group-containing silane compounds, (meth)acryloyl group-containing silane compounds, amino group-containing silane compounds, isocyanate group-containing silane compounds, isocyanurate group-containing silane compounds, epoxy group-containing silane compounds and mercapto group-containing silane compounds.

[0013] [6] The optical laminate according to [5], wherein the silane compound is a (meth)acryloyl group-containing silane compound.

[0014] [7] The optical laminate according to [2], wherein the hard coat layer contains a binder resin and silica particles (A), and the functional group derived from the silane compound has the same functional group as the binder resin.

[0015] [8] The hard coat layer contains a binder resin, silica particles (A), and silica particles (B), and the functional group derived from the silane compound has the same functional group as the binder resin. The optical laminate according to [4]. [9] The binder resin contains a (meth)acrylate compound, and the functional group derived from the silane compound is a (meth)acryloyl group. The optical laminate according to [7] or [8].

[0016]

[10] The optical laminate according to [1], wherein the thickness of the hard coat layer is 0.5 μm or more and 100 μm or less.

[0017]

[11] The optical laminate according to [1], wherein the optical functional layer includes a high refractive index layer and a low refractive index layer having a lower refractive index than the high refractive index layer.

[0018]

[12] When the optical laminate is bent 180° by a flat body unloaded U-shaped expansion and contraction tester so that the surface on which the antifouling layer is formed faces inward, the compression ratio C (%) of the optical functional layer calculated by the following formula (2) when bent until reaching the minimum bending radius at which no crack occurs satisfies 4.5 ≦ C. The optical laminate according to [1]. C(%) = {1 - (R3 / R1)} × 100... (2) (However, R3 is the distance obtained by subtracting the thickness of the optical laminate from half of the distance between the plates, and R1 is the distance obtained by subtracting half of the thickness of the optical laminate from half of the distance between the plates.)

[13] An article provided with the optical laminate according to any one of [1] or [2].

[0019] According to the present invention, it is possible to provide an optical laminate that realizes excellent scratch resistance and further improves bending resistance, and an article provided with the same. Further, it is possible to provide an optical laminate with high transparency by suppressing an increase in haze value and an article provided with the same.

[0020] It is a cross-sectional view showing an example of the optical laminate of this embodiment. It is a cross-sectional view showing another example of the optical laminate of this embodiment. It is a schematic view for explaining an example of a manufacturing apparatus that can be used in the manufacturing method of the optical laminate of this embodiment. It is a schematic view for explaining an example of an article provided with the optical laminate of this embodiment.

[0021] Hereinafter, this embodiment will be described in detail with appropriate reference to the drawings. The drawings used in the following description may show, for the sake of convenience, the characteristic parts enlarged in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may be different from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto, and it can be appropriately modified and implemented within the range in which the effects are achieved. In this specification, the refractive index refers to the refractive index at a wavelength of 550 nm unless otherwise specified.

[0022] [Optical laminate] FIG. 1 is a cross-sectional view showing another example of the optical laminate of this embodiment. The optical laminate 102 shown in FIG. 1 is formed by laminating a transparent base material 11, a hard coat layer 12, an adhesion layer 13, an optical functional layer 14, and an antifouling layer 15 in this order. The adhesion layer 13 is a layer that exhibits adhesion between the hard coat layer 12 and the optical functional layer 14. The optical functional layer 14 is a layer that exhibits an optical function. The optical function is a function of controlling properties of light such as reflection, transmission, and refraction, and examples thereof include an antireflection function, a selective reflection function, and a lens function. The optical functional layer 14 preferably contains any one selected from an antireflection layer and a selective reflection layer. Known ones can be used as the antireflection layer and the selective reflection layer. The antireflection layer and the selective reflection layer may each be a single layer or a laminate of a plurality of layers.

[0023] FIG. 2 is a cross-sectional view showing another example of the optical laminate of this embodiment. The optical laminate 10 shown in FIG. 2 has an antireflection layer provided as the optical functional layer 14 in the optical laminate 102 shown in FIG. 1. As shown in FIG. 2, the optical functional layer 14 (antireflection layer) is composed of a laminate in which a low refractive index layer 14b and a high refractive index layer 14a are alternately laminated. The optical functional layer 14 shown in FIG. 2 is laminated in this order with the hard coat layer 12, the adhesion layer 13, the high refractive index layer 14a, the low refractive index layer 14b, the high refractive index layer 14a, the low refractive index layer 14b, and the antifouling layer 15 from the side of the transparent base material 11. Therefore, the antifouling layer 15 is in contact with the low refractive index layer 14b of the optical functional layer 14.

[0024] The transparent substrate 11 can be formed from a transparent material capable of transmitting light in the visible light range. For example, a plastic film is preferably used as the transparent substrate 11. Specific examples of constituent materials of the plastic film include polyester resins, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, and polyphenylene sulfide resins.

[0025] In this invention, "transparent material" refers to a material with a light transmittance of 80% or more in the wavelength range used, as long as it does not impair the effects of the present invention. In this embodiment, "(meth)acrylic" means methacrylic and acrylic.

[0026] The transparent substrate 11 may contain a reinforcing material, provided that it does not significantly impair the optical properties. Examples of reinforcing materials include cellulose nanofibers and nanosilica.

[0027] If the plastic film is a PET substrate, the optical laminate 102 can be manufactured with a good balance between optical properties and material cost. If the plastic film is a CPI substrate (transparent polyimide), it has good bending performance, so the optical laminate 102 can be manufactured with even better bending resistance. If the plastic film is a TAC substrate, when a hard coat layer 12 is formed on one side thereof, a permeation layer is formed in which some of the components constituting the hard coat layer 12 penetrate. As a result, the adhesion between the transparent substrate 11 and the hard coat layer 12 is improved, and the generation of interference fringes caused by the difference in refractive index between the layers can be suppressed.

[0028] The transparent substrate 11 may be a film to which optical and / or physical functions are imparted. Examples of films having optical and / or physical functions include polarizing plates, phase difference compensation films, heat shielding films, transparent conductive films, brightness-enhancing films, and barrier-enhancing films.

[0029] The thickness of the transparent substrate 11 is not particularly limited, but is preferably 20 μm or more, and more preferably 30 μm or more. When the thickness of the transparent substrate 11 is 20 μm or more, the rigidity of the substrate itself is ensured, and wrinkles are less likely to occur even when stress is applied to the optical laminate 10. Furthermore, when the thickness of the transparent substrate 11 is 20 μm or more, wrinkles are less likely to occur even when the hard coat layer 12 is continuously formed on the transparent substrate 11, which is preferable as it reduces manufacturing concerns. When the thickness of the transparent substrate 11 is 30 μm or more, wrinkles are even less likely to occur, which is preferable.

[0030] When manufacturing is carried out using a roll, the thickness of the transparent substrate 11 is, for example, 1000 μm or less, preferably 600 μm or less, more preferably 300 μm or less, even more preferably 200 μm or less, and may also be 100 μm or less or 80 μm or less. When the thickness of the transparent substrate 11 is 600 μm or less, the optical laminate 10 during manufacturing and the optical laminate 10 after manufacturing can be easily wound into a roll, and the optical laminate 10 can be manufactured efficiently. Furthermore, when the thickness of the transparent substrate 11 is 600 μm or less, it becomes possible to make the optical laminate 10 thinner and lighter. When the thickness of the transparent substrate 11 is 300 μm or less, the optical laminate 10 can be manufactured more efficiently, and further thinning and weight reduction is possible, which is preferable. Furthermore, when the thickness of the transparent substrate 11 is 100 μm or less, cracking of the transparent substrate 11 is less likely to occur when bent, and bending resistance is improved, which is more preferable.

[0031] The transparent substrate 11 may have its surface pre-treated with etching treatments such as sputtering, corona discharge, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, and / or undercoating treatments. These treatments can improve adhesion with the hard coat layer 12 formed on the transparent substrate 11. Furthermore, before forming the hard coat layer 12 on the transparent substrate 11, it is preferable to remove dust and clean the surface of the transparent substrate 11 by performing solvent cleaning, ultrasonic cleaning, etc., as needed.

[0032] The hard coat layer 12 consists of a binder resin and a filler as essential components, and may contain other components such as a dispersant as optional components. Known binder resins can be used. The filler is included in the binder resin to the extent that it does not impair transparency. The filler may be made of organic materials, inorganic materials, or a combination of organic and inorganic materials. However, from the viewpoint of hardness and flexibility, inorganic materials are preferred, and silica particles made of silicon oxide are even more preferred. Furthermore, silica particles with surface modification are particularly preferred.

[0033] The binder resin used in the hard coat layer 12 is preferably transparent, and for example, ionizing radiation-curable resins that harden with ultraviolet light or electron beams, thermoplastic resins, thermosetting resins, etc. can be used.

[0034] Examples of ionizing radiation-curable resins used in the binder resin of the hard coat layer 12 include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinylpyrrolidone, etc. Furthermore, examples of compounds that are ionizing radiation-curable resins having two or more unsaturated bonds include trimethylolpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, 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, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. Examples of polyfunctional compounds include lysritol 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, isobolonyl di(meth)acrylate, dicyclopentane di(meth)acrylate, tricyclodecane di(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate. Among these, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), and pentaerythritol tetraacrylate (PETTA) are preferably used. Note that "(meth)acrylate" refers to both methacrylate and acrylate. In addition, as an ionizing radiation-curable resin, compounds modified with PO (propylene oxide), EO (ethylene oxide), CL (caprolactone), etc., as described above can also be used.Furthermore, urethane (meth)acrylate oligomers and epoxy (meth)acrylate oligomers can also be used from the viewpoint of hard coat layer film formation and viscoelasticity adjustment.

[0035] Examples of thermoplastic resins used in the binder resin of the hard coat layer 12 include styrene resins, (meth)acrylic resins, vinyl acetate resins, vinyl ether resins, halogen-containing resins, alicyclic olefin resins, polycarbonate resins, polyester resins, polyamide resins, cellulose derivatives, silicone resins, and rubber or elastomers. The thermoplastic resin is preferably amorphous and soluble in organic solvents (especially a common solvent capable of dissolving multiple 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.) are preferred.

[0036] The hard coat layer 12 includes, for example, a binder resin and silica particles as fillers. In this embodiment, the hard coat layer 12 contains silica particles (A) with an average particle diameter of 65 nm or more. The average particle diameter of the silica particles (A) is preferably 70 nm or more, and more preferably 75 nm or more. Setting the average particle diameter of the silica particles (A) to 65 nm or more can improve the flexibility of the optical laminate 10. The average particle diameter of the silica particles (A) can be calculated, for example, using particle diameter and particle number values ​​obtained by observation using a scanning electron microscope or a transmission electron microscope. When using a scanning electron microscope (SEM), the average particle diameter of the silica particles (A) is obtained by photographing the silica particles (A) with the SEM, and for the silica particles (A) confirmed on the two-dimensional image, the maximum length of the distance between two points on the contour line of the primary particles of 50 or more randomly selected silica particles (A) is taken as the particle diameter, and the average value is adopted.

[0037] The silica particles (A) preferably include silica particles that have been surface-modified in advance. The compound used as a surface treatment agent when surface-modifying the silica particles is not particularly limited, and known coupling agents can be used, but it is preferable to use a silane compound. Specific examples of silane compounds include vinyl group-containing silane compounds, (meth)acryloyl group-containing silane compounds, amino group-containing silane compounds, isocyanate group-containing silane compounds, isocyanurate group-containing silane compounds, epoxy group-containing silane compounds, and mercapto group-containing silane compounds, and these may be used individually or in combination. The silane compound is appropriately selected according to the type of binder resin, but if the binder resin contains functional groups, a silane compound having the same functional groups as the binder resin is preferred. For example, if the binder resin contains a (meth)acrylate compound as an ionizing radiation-curable resin, a (meth)acryloyl group-containing alkoxysilane compound is preferred as the silane compound. Note that "(meth)acrylate" refers to methacrylate and / or acrylate. In this invention, methacrylate and acrylate are treated as the same substance in terms of their reaction mechanism. The silane compound used for surface modification preferably has alkoxysilyl or silanol groups at its terminus, as this facilitates good bonding with hydroxyl groups present on the surface of the silica particles. Pre-surface modification of the silica particles improves their dispersibility in the binder resin and strengthens their bond with the binder resin through the reaction of the surface treatment agent used for surface modification, thereby improving the hardness of the optical laminate. These silica particles may be exposed on the surface of the hard coat layer 12 on the optical functional layer 14 side. In this case, the hard coat layer 12 and the optical functional layer 14 are more strongly bonded via the adhesion layer 13. Methods for exposure include glow treatment, which will be described later, in which case the surface modification of the exposed silica surface is removed. When the silica particles are exposed on the hard coat layer surface and the surface modification is removed, an electrostatic attraction is generated between the hydroxyl groups formed on the filler surface and the adhesion layer 13, which will be described later, further improving adhesion.Furthermore, the exposed silica particles act as anchors, embedding themselves into the adhesion layer 13, which also contributes to improved adhesion. The improvement in flexibility is achieved through a combination of the bonding with the binder resin due to the surface modification of the silica particle surface mentioned above, and the interaction between the silica particles and the adhesion layer.

[0038] The average particle diameter of the silica particles (A) in the hard coat layer 12 is, for example, 800 nm or less, preferably 400 nm or less, more preferably 140 nm or less, and may also be 120 nm or less or 100 nm or less. If the average particle diameter of the silica particles (A) is 800 nm or less, the flexibility of the optical laminate 10 can be improved. Furthermore, if the average particle diameter of the silica particles (A) is 140 nm or less, the haze value of the entire optical laminate 10 can be reduced to 2% or less. An optical laminate 10 with a haze of 2% or less has high transparency and becomes a so-called clear type anti-reflective film.

[0039] The hard coat layer 12 preferably further contains silica particles (B) with an average particle diameter of 55 nm or less. The average particle diameter of the silica particles (B) is preferably 53 nm or less, and more preferably 50 nm or less. Generally, increasing the particle diameter of the silica particles contained in the hard coat layer 12 tends to increase the haze value of the entire optical laminate 10. If the average particle diameter of the silica particles (B) is within this range, by using a combination of silica particles (A) with a large average particle diameter and silica particles (B) with a small average particle diameter, the haze value of the entire optical laminate 10 can be further reduced while maintaining the good flexibility of the optical laminate 10, thereby increasing transparency. The average particle diameter of the silica particles (B) can be calculated, for example, using particle diameter and particle number values ​​obtained by observation using a scanning electron microscope or a transmission electron microscope. The method for measuring the average particle diameter of the silica particles (B) is the same as the method for measuring the average particle diameter of the silica particles (A).

[0040] The mass % (M) of silica particles (A) relative to the total solid content of the hard coat layer composition Ａ ) and the mass % (M) of silica particles (B) relative to the total solid content of the hard coat layer composition. Ｂ ) ratio ((M Ａ ) / (M Ｂ)) is preferably 0.1 or more and 9.0 or less. Further, the ratio ((M Ａ ) / (M Ｂ )) is more preferably 0.2 or more and 6.0 or less, and even more preferably 0.25 or more and 5.0 or less. When the ratio ((M Ａ ) / (M Ｂ )) is 0.1 or more and 9.0 or less, while maintaining good bending resistance of the optical laminate 10, an increase in the haze value of the entire optical laminate 10 can be further suppressed, and the transparency of the optical laminate 10 can be improved.

[0041] Also, the mass% (M Ａ ) of the silica particles (A) with respect to the total solid content of the hard coat layer composition and the mass% (M Ｂ ) of the silica particles (B) with respect to the total solid content of the hard coat layer composition, the ratio ((M Ａ ) / (M Ａ + M Ａ )) of the mass% (M Ｂ ) of the silica particles (A) with respect to the total solid content of the hard coat layer composition is preferably 0.10 or more and 0.90 or less. Further, the ratio ((M Ａ ) / (M Ａ + M Ｂ )) is more preferably 0.15 or more and 0.86 or less, and even more preferably 0.20 or more and 0.80 or less. When the ratio ((M Ａ ) / (M Ａ + M Ｂ )) is 0.10 or more and 0.90 or less, while maintaining good bending resistance of the optical laminate 10, an increase in the haze value of the entire optical laminate 10 can be further suppressed.

[0042] It is preferable that the silica particles (B) include silica particles that have been pre-surface modified. Specific examples of silane compounds used for surface modification of silica particles (B) are the same as those used for surface modification of silica particles (A). Also, as with silica particles (A), the silane compound used for surface modification of silica particles (B) is appropriately selected depending on the type of binder resin, but if the binder resin contains functional groups, a silane compound having the same functional groups as the binder resin is preferred.

[0043] When the hard coat layer 12 contains silica particles (A) and silica particles (B), it is preferable that both of the silica particles (A) and (B) contain silica particles that have been pre-surface modified, but either of the silica particles (A) or (B) may contain silica particles that have been pre-surface modified. For example, of the silica particles (A) and (B) contained in the hard coat layer 12, the one with a higher mass percentage of silica particles relative to the total solid content of the hard coat layer composition may contain silica particles that have been pre-surface modified, while the one with a lower mass percentage of silica particles relative to the total solid content of the hard coat layer composition may not be surface modified.

[0044] The average particle size of the silica particles (B) in the hard coat layer 12 may be, for example, 10 nm or more, 20 nm or more, or 30 nm or more. If the average particle size of the silica particles (B) is within this range, an optical laminate 10 with a good balance between flexibility and overall haze value can be obtained.

[0045] In this embodiment, the hard coat layer 12 contains silica particles (A) with an average particle diameter of 65 nm or more, but is not limited to this, and may contain a predetermined amount or more of silica particles with a predetermined particle size or larger. Specifically, the hard coat layer 12 may contain 5% to 60% by mass of silica particles with a particle diameter of 65 nm or more, when the total solid content of the hard coat layer 12 is considered to be 100% by mass. The mass percentage of silica particles with a particle diameter of 65 nm or more relative to the total solid content of the hard coat layer 12 is calculated, for example, from the values ​​of the total solid content of the hard coat layer 12 and the specific gravity of the silica particles measured by a known method, and from the particle diameter, number of particles, and volume ratio of silica particles to the total solid content of the hard coat layer 12 obtained by observation using a scanning electron microscope or a transmission electron microscope. In this case, the optical laminate 10 may also satisfy conditions 1 and 2 described later. This configuration can also achieve excellent scratch resistance and further improve flexibility. In addition, it is preferable that these silica particles, like silica particles (A) and (B), include silica particles that have been pre-surface-modified.

[0046] Furthermore, in the above configuration, the hard coat layer 12 may contain 5% to 60% by mass of silica particles with a particle size of 55 nm or less, when the total solid content of the hard coat layer 12 is considered to be 100% by mass.

[0047] The hard coat layer 12 is preferably subjected to treatments such as glow discharge treatment, plasma treatment, ion etching, or alkaline treatment on its surface. Among these, glow discharge treatment is preferred because it allows for large-area treatment. The intensity of the glow discharge treatment is, for example, 100 W / m² as the electrode power density. ２ ~11000W / m ２ This can be done at 1600W / m ２ ~7000W / m ２It is preferable to perform the glow discharge treatment on the surface of the hard coat layer 12. By performing glow discharge treatment on the surface of the hard coat layer 12, the surface of the hard coat layer 12 is roughened at the nano level, and weakly bonding substances present on the surface of the hard coat layer 12 are removed. As a result, the adhesion between the hard coat layer 12 and the adhesion layer 13 formed on the hard coat layer 12 is improved. It also has the effect of exposing silica particles from the hard coat layer 12. Furthermore, although increasing the strength during the discharge treatment tends to improve the flexibility resistance described later, the effect plateaus above a certain discharge strength, and excessive glow discharge strength can lead to deterioration of the resin constituting the hard coat layer. Therefore, it is preferable to perform the glow discharge treatment at the aforementioned range of discharge strength.

[0048] Furthermore, if an anti-glare optical laminate is to be obtained, the hard coat layer 12 may contain fillers with an average particle size of, for example, 0.5 μm or more or 1 μm or more. For such fillers, organic fine particles such as acrylic resin are preferably used. By using fillers with a particle size within this range, irregularities are formed on the surface of the hard coat layer, providing anti-glare properties, thus resulting in a so-called anti-glare (AG) type anti-reflective film. In this case, the average particle size of the filler is preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 5 μm or less. As fillers contained in the hard coat layer 12, various reinforcing materials can be used to provide toughness to the hard coat layer 12, within a range that does not impair optical properties. Examples of reinforcing materials include cellulose nanofibers.

[0049] The thickness of the hard coat layer 12 is not particularly limited, but is preferably 0.5 μm or more, more preferably 1 μm or more. The thickness of the hard coat layer 12 is preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. If the thickness of the hard coat layer 12 is 0.5 μm or more, sufficient hardness is obtained, making it less likely for scratches to occur during manufacturing. Also, if the thickness of the hard coat layer 12 is 50 μm or less, microcracks in the hard coat layer 12 that occur when the optical laminate 10 is bent during manufacturing are less likely to occur, resulting in good productivity. Also, if the thickness of the hard coat layer 12 is 20 μm or less, it becomes possible to make the optical laminate 10 thinner and lighter.

[0050] The hard coat layer 12 may be a single layer or a laminate of multiple layers. Furthermore, the hard coat layer 12 may be provided with known functions such as ultraviolet absorption, antistatic properties, refractive index adjustment, and hardness adjustment. The functions provided to the hard coat layer 12 may be provided within a single hard coat layer or divided and provided across multiple layers.

[0051] The adhesion layer 13 is a layer formed to improve adhesion between the hard coat layer 12, which is an organic film, and the optical functional layer 14, which is an inorganic film. In the optical laminate 10 shown in Figure 2, the adhesion layer 13 is provided between the hard coat layer 12 and the optical functional layer 14, and the adhesion layer 13 has the function of bringing the hard coat layer 12 and the optical functional layer 14 into close contact. The adhesion layer 13 is preferably made of an oxygen-deficient metal oxide or metal. An oxygen-deficient metal oxide refers to a metal oxide in which the number of oxygen atoms is insufficient compared to the stoichiometric composition. Examples of oxygen-deficient metal oxides include SiOx, AlOx, TiOx, ZrOx, CeOx, MgOx, ZnOx, TaOx, SbOx, SnOx, and MnOx. Examples of metals include Si, Al, Ti, Zr, Ce, Mg, Zn, Ta, Sb, Sn, Mn, and In. The adhesion layer 13 may, for example, have x in SiOx greater than 0 and less than 2.0. The adhesion layer may also be formed from a mixture of multiple metals or metal oxides. From the viewpoint of maintaining transparency and adhesion to the optical functional layer and obtaining good optical properties, the thickness of the adhesion layer is preferably greater than 0 nm and less than or equal to 20 nm, and particularly preferably between 1 nm and 10 nm. The method for forming the film constituting the adhesion layer is not particularly limited, but dry coating methods such as vacuum deposition, CVD, sputtering, and electron beam vapor deposition are preferred because they can form thin films with uniform thickness. Among these, sputtering is preferred because it offers excellent uniformity of film thickness and easily forms a dense film. In this specification, a thin film formed by sputtering is referred to as a sputtered film.

[0052] In this embodiment, the optical laminate 10 has an adhesion layer 13, but it is not limited to this and may not have an adhesion layer 13. For example, if the adhesion between the hard coat layer 12 and the optical functional layer 14 is good, the optical laminate 10 does not have an adhesion layer 13, and the hard coat layer 12 and the optical functional layer 14 are provided in contact with each other. In this case, the optical laminate 10 can have a simple laminated structure.

[0053] The optical functional layer 14 is, for example, a laminate that exhibits an anti-reflective function. When the optical functional layer 14 is an anti-reflective layer, it is, for example, a laminate of multiple thin films with different refractive indices, preferably an alternating laminate of high refractive index layers and low refractive index layers. The optical functional layer 14 shown in Figure 2 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 from the adhesion 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. For example, the optical functional layer 14 can have a configuration that includes a high refractive index layer 14a and a low refractive index layer 14b, or it can have a configuration that includes either a high refractive index layer 14a or a low refractive index layer 14b. The method for depositing the thin films constituting the optical functional layer is not particularly limited, and either a wet coating method or a dry coating method may be used. Dry coating methods such as vacuum deposition, CVD, sputtering, and electron beam vapor deposition are preferred because they can form thin films with uniform thickness. Among these, sputtering is preferred because it offers excellent uniformity of film thickness and easily forms dense films.

[0054] In the optical laminate 10 shown in Figure 2, the optical functional layer 14 consists of a laminate in which low refractive index layers 14b and high refractive index layers 14a are alternately stacked. Therefore, light incident from the antifouling layer 15 side interferes with each other through the optical functional layer 14, reducing the intensity of reflected light and enabling an anti-reflective function. Thus, an anti-reflective function is obtained that prevents light incident from the antifouling layer 15 side from being reflected in one direction.

[0055] The low refractive index layer 14b contains, for example, a metal oxide. Specifically, silicon oxide (SiO₂) ２ ), titanium nitride (TiN), magnesium fluoride (MgF ２ ), calcium fluoride (CaF ２ Examples include those listed above. Among them, Si oxide may be included due to its ease of availability and cost, and SiO ２ It is preferable that the layer is mainly composed of (silicon oxides), etc. ２The single layer film is colorless and transparent. In this embodiment, the main component of the low refractive index layer 14b means a component that is present in the low refractive index layer 14b at a concentration of 50% by mass or more. If the low refractive index layer 14b is a layer mainly composed of Si oxide, it may also contain other elements at a concentration of less than 50% by mass. 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 the purpose of improving alkali resistance.

[0056] The refractive index of the low refractive index layer 14b is preferably 1.2 to 1.6, and more preferably 1.3 to 1.5.

[0057] The refractive index of the high refractive index layer 14a is preferably 2.0 to 2.6, and more preferably 2.1 to 2.5. The dielectric material used for the high refractive index layer 14a is niobium pentoxide (Nb ２ O ５ ), titanium oxide (TiO ２ ), tungsten oxide (WO ３ ), cerium oxide (CeO ２ ), tantalum pentoxide (Ta ２ O ５ ), zinc oxide (ZnO), indium tin oxide (ITO), zirconium oxide (ZrO) ２ Examples include the above. If it is desired to impart conductive properties to the high refractive index layer 14a, for example, ITO or indium zinc oxide (IZO) can be selected.

[0058] For example, the optical functional layer 14 may be made of niobium pentoxide (Nb₂O₅) as the high refractive index layer 14a, and SiO₂ as the low refractive index layer 14b. ２ It is preferable to use one consisting of the following:

[0059] The film thickness of the low refractive index layer 14b may be, for example, in the range of 1 nm to 200 nm, and can be appropriately selected according to the wavelength range in which anti-reflective function is required. The film thickness of the high refractive index layer 14a may be, for example, in the range of 1 nm to 200 nm, and can be appropriately selected according to the wavelength range in which anti-reflective function is required. The film thicknesses of the high refractive index layer 14a and the low refractive index layer 14b can each be appropriately selected according to the design of the optical functional layer 14. For example, starting from the adhesion layer 13 side, the layers can be, in order: high refractive index layer 14a of 5 to 50 nm, low refractive index layer 14b of 10 to 80 nm, high refractive index layer 14a of 20 to 200 nm, and low refractive index layer 14b of 50 to 200 nm.

[0060] Of the layers forming the optical functional layer 14, a low refractive index layer 14b is arranged on the side facing the antifouling layer 15. When the low refractive index layer 14b of the optical functional layer 14 is in contact with the antifouling layer 15, the anti-reflective performance of the optical functional layer 14 is improved, which is preferable.

[0061] The antifouling layer 15 is formed on the outermost surface of the optical functional layer 14 and prevents contamination of the optical functional layer 14. Furthermore, when applied to touch panels and the like, the antifouling layer 15 suppresses wear of the optical functional layer 14 due to its abrasion resistance. Known materials can be used as the material for the antifouling layer 15, such as fluorine-based organic compounds and fluorine-free silicone-based compositions. The antifouling layer 15 can be formed by wet coating methods such as reverse coating, die coating, and gravure coating, or by dry coating methods such as vacuum deposition and CVD. In this embodiment, the antifouling layer 15 is formed by vacuum deposition of a fluorine-based organic compound as an antifouling material on one surface of the low refractive index layer 14b that constitutes the optical functional 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.

[0062] Preferably, the fluorine-based organic compound constituting the antifouling layer 15 is a compound consisting of a fluorine-modified organic group and a reactive silyl group (e.g., alkoxysilane). Commercially available products include Optool DSX (manufactured by Daikin Corporation) and the KY-100 series (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0063] 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 (e.g., alkoxysilane) is used, and as the low refractive index layer 14b of the optical functional layer 14 in contact with the antifouling layer 15, SiO ２ When using a material consisting of the silanol group, which is the skeleton of the fluorine-based organic compound, and SiO ２ A siloxane bond is formed between them. This results in good adhesion between the optical functional layer 14 and the anti-fouling layer 15, which is desirable.

[0064] The optical thickness of the antifouling layer 15 may be, for example, 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. If the optical 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 touch panel applications, etc. If the optical thickness of the antifouling layer 15 is 3 nm or more, the liquid resistance of the optical laminate 10 is improved. Furthermore, if the optical thickness of the antifouling layer 15 is 20 nm or less, the time required for deposition is shortened, and manufacturing can be done efficiently.

[0065] In the optical laminates 10 and 102 configured as described above, the ratio ((A) / (B)) of the Martens hardness (A) measured from the antifouling layer 15 side of the optical laminates 10 and 102 to the Martens hardness (B) measured from the hard coat layer 12 side of the laminate having only the transparent substrate 11 and the hard coat layer 12 is 3.65 or less (Condition 1). Furthermore, the above ratio ((A) / (B)) is preferably 3.5 or less, and more preferably 3.0 or less. When the above ratio ((A) / (B)) is 3.65 or less, the difference in hardness between the hard coat layer surface and the antifouling layer surface becomes small, which suppresses deformation, and as a result, excellent scratch resistance can be achieved, and flexibility can be further improved.

[0066] Furthermore, in the optical laminates 10 and 102 configured as described above, a friction tester using steel wool conforming to JIS L0849 is used, and the difference in contact angle with water before friction and after friction in which the steel wool is moved horizontally 200 times is 20° or less (Condition 2). If the hardness of the optical laminates 10 and 102 is high, the above contact angle difference will be 20° or less, and excellent scratch resistance can be achieved.

[0067] In the optical laminates 10 and 102 configured as described above, when the optical laminates 10 and 102 are bent 180° so that the surface on which the antifouling layer 15 is formed faces inward, the compression ratio C (%) of the optical functional layer 14, calculated by the following formula (1), using the mandrel with the smallest diameter that does not produce cracks, preferably satisfies 4.5 ≤ C, and more preferably satisfies 5 ≤ ​​C. This further improves the bending resistance of the optical laminates 10 and 102. C (%) = {1 - (R3 / R1)} × 100 ... (1) (wherein R3 is the distance from the axis center of the mandrel to the surface of the optical laminate facing the antifouling layer, and R1 is the distance from the axis center of the mandrel to a virtual line indicating a position corresponding to half the total thickness of the optical laminate.)

[0068] Furthermore, the mandrel diameter and compression ratio C in the mandrel test described above shall be calculated from the average value of three measurements taken from three identical samples.

[0069] Furthermore, in the optical laminates 10 and 102 configured as described above, when the optical laminates 10 and 102 are bent 180° using a planar body unloaded U-shaped stretch tester with the surface on which the anti-fouling layer 15 is formed facing inward, the compression ratio C (%) of the optical functional layer 14, calculated by the following formula (2), when bent to the minimum bending radius at which no cracks occur, preferably satisfies 4.5 ≤ C, more preferably 5 ≤ C, and even more preferably 8 ≤ C. This further improves the bending resistance of the optical laminates 10 and 102. C (%) = {1 - (R3 / R1)} × 100 ... (2) (wherein R3 is the distance obtained by subtracting the thickness of the optical laminate from half the distance between the flat plates, and R1 is the distance obtained by subtracting half the thickness of the optical laminate from half the distance between the flat plates.)

[0070] Furthermore, the compression ratio C in the unloaded U-shaped test described above shall be calculated from the average value of three measurements taken from three identical samples.

[0071] [Method for Manufacturing an Optical Laminate] The optical laminate 10 of this embodiment shown in Figure 2 can be manufactured, for example, by the method described below. In this embodiment, as an example of a method for manufacturing the optical laminate 10, the case in which the optical laminate 10 is manufactured using a transparent substrate 11 wound in a roll shape will be described. First, the transparent substrate 11 wound in a roll shape is unwound. Then, a slurry containing a material that will become the hard coat layer 12 is applied to the transparent substrate 11 by a known method, and cured by a known method corresponding to the material that will become the hard coat layer 12. Examples of slurry used include a composition containing a binder resin and silica particles (A) as a filler, and this composition is applied to the transparent substrate 11 and then cured. This forms a hard coat layer 12 on the transparent substrate 11 (hard coat layer formation step). The above composition may contain one or more additives such as a polymerization initiator and a leveling agent as needed. As a polymerization initiator, for example, a photopolymerization initiator is used. After that, the transparent substrate 11 with the hard coat layer 12 formed on its surface is wound into a roll shape by a known method.

[0072] Next, an adhesion layer forming step is performed to form an adhesion layer 13 on the hard coat layer 12, and an optical functional layer forming step is performed to form an optical functional layer 14. After that, an antifouling layer forming step is performed to form an antifouling layer 15 on the optical functional layer 14. In this embodiment, it is preferable to perform a first surface treatment step to treat the surface of the hard coat layer 12 before performing the adhesion layer forming step and the optical functional layer forming step. Also, in this embodiment, it is preferable to perform a second surface treatment step to treat the surface of the optical functional layer 14 after the optical functional layer forming step before performing the antifouling layer forming step.

[0073] In the manufacturing method of the optical laminate 10 of this embodiment, it is preferable that the first surface treatment step, the adhesion layer formation step, the optical functional layer formation step, the second surface treatment step, and the antifouling layer formation step be carried out continuously while maintaining the optical laminate in the process of manufacturing under reduced pressure. When the first surface treatment step, the adhesion layer formation step, the optical functional layer formation step, the second surface treatment step, and the antifouling layer formation step are carried out continuously while maintaining the optical laminate in the process of manufacturing under reduced pressure, for example, a known apparatus equipped with a thin film forming apparatus can be used as a sputtering apparatus.

[0074] A specific example of a manufacturing apparatus that can be used in the manufacturing method of the optical laminate of this embodiment is the manufacturing apparatus 20 shown in Figure 3. The manufacturing apparatus 20 shown in Figure 3 comprises a roll unwinding device 4, a pretreatment device 2A, a sputtering device 1, a pretreatment device 2B, a vapor deposition device 3, and a roll winding device 5. As shown in Figure 3, these devices 4, 2A, 1, 2B, 3, and 5 are connected in this order. The manufacturing apparatus 20 shown in Figure 3 is a roll-to-roll type manufacturing apparatus that continuously forms multiple layers on a substrate by unwinding the substrate from a roll, passing it through the connected devices (in Figure 3, the pretreatment device 2A, the sputtering device 1, the pretreatment device 2B, and the vapor deposition device 3) in succession, and then winding it up.

[0075] When manufacturing the optical laminate 10 using a roll-to-roll manufacturing apparatus, the transport speed (line speed) of the optical laminate 10 during manufacturing can be set as appropriate. The transport speed is preferably 0.5 to 20 m / min, and more preferably 0.5 to 10 m / min.

[0076] <Roll Unwinding Device> The roll unwinding device 4 shown in Figure 3 comprises a chamber 34 whose interior is kept in a predetermined reduced-pressure atmosphere, one or more vacuum pumps 21 (one in Figure 3) that discharge the gas from the chamber 34 to create a reduced-pressure atmosphere, and an unwinding roll 23 and a guide roll 22 installed inside the chamber 34. As shown in Figure 3, the chamber 34 is connected to the chamber 31 of the sputtering device 1 via the pretreatment device 2A. A transparent substrate 11 with a hard coat layer 12 formed on its surface is wound around the unwinding roll 23. The unwinding roll 23 supplies the transparent substrate 11 with the hard coat layer 12 formed on its surface to the pretreatment device 2A at a predetermined transport speed.

[0077] <Pretreatment device 2A> The pretreatment device 2A shown in Figure 3 comprises a chamber 32 whose interior is kept in a predetermined reduced-pressure atmosphere, a can roll 26, a plurality (two in Figure 3) of guide rolls 22, and a plasma discharge device 42. As shown in Figure 3, the can roll 26, the guide rolls 22, and the plasma discharge device 42 are installed inside the chamber 32. As shown in Figure 3, the chamber 32 is connected to the chamber 31 of the sputtering device 1.

[0078] The can roll 26 and guide roll 22 transport the transparent substrate 11, on which the hard coat layer 12 is formed, from the roll unwinding device 4 at a predetermined transport speed, and send the transparent substrate 11 with the hard coat layer 12 surface treated to the sputtering device 1. As shown in Figure 3, the plasma discharge device 42 is positioned opposite the outer circumferential surface of the can roll 26 at a predetermined distance apart. The plasma discharge device 42 ionizes a gas by glow discharge. The gas is preferably inexpensive, inert, and does not affect the optical properties. For example, argon gas, oxygen gas, nitrogen gas, helium gas, etc., can be used. In this embodiment, it is preferable to use argon gas or oxygen gas as the gas.

[0079] <Sputtering Apparatus> The sputtering apparatus 1 shown in Figure 3 comprises a chamber 31 whose interior is kept under a predetermined reduced pressure atmosphere, one or more vacuum pumps 21 (two in Figure 3) that discharge the gas from the chamber 31 to create a reduced pressure atmosphere, a film deposition roll 25, a plurality of guide rolls 22 (two in Figure 3), and a plurality of film deposition units 41 (four in the example shown in Figure 3). As shown in Figure 3, the film deposition roll 25, the guide rolls 22, and the film deposition units 41 are installed inside the chamber 31. As shown in Figure 3, the chamber 31 is connected to the chamber 32 of the pretreatment apparatus 2B.

[0080] The film-forming roll 25 and guide roll 22 transport the transparent substrate 11, which has a hard coat layer 12 formed on its surface and has been sent from the pre-processing device 2A, at a predetermined transport speed, and supply the transparent substrate 11, on which an adhesion layer 13 and an optical functional layer 14 have been formed on the hard coat layer 12, to the pre-processing device 2B. In the sputtering apparatus 1 shown in Figure 3, the adhesion layer 13 is laminated on the hard coat layer 12 of the transparent substrate 11 running on the film-forming roll 25 by sputtering, and then a high refractive index layer 14a and a low refractive index layer 14b are alternately laminated on top of that to form the optical functional layer 14.

[0081] As shown in Figure 3, the film-forming sections 41 are arranged opposite the outer surface of the film-forming roll 25 at a predetermined distance apart, and multiple sections are provided to surround the film-forming roll 25. The number of film-forming sections 41 is determined according to the total number of layers of the adhesion layer 13 and the high refractive index layer 14a and low refractive index layer 14b that form the optical functional layer 14. If it is difficult to secure distance between adjacent film-forming sections 41 due to a large total number of layers of the adhesion layer 13 and the high refractive index layer 14a and low refractive index layer 14b forming the optical functional layer 14, multiple film-forming rolls 25 may be provided in the chamber 31, and the film-forming sections 41 may be arranged around each film-forming roll 25. When multiple film-forming rolls 25 are provided, guide rolls 22 may be installed as needed. Multiple chambers 31 equipped with film-forming rolls 25 and film-forming sections 41 may be connected together. In addition, the diameter of the film-forming roll 25 may be appropriately changed to make it easier to secure distance between adjacent film-forming sections 41.

[0082] Each film deposition section 41 is equipped with a predetermined target (not shown). A voltage is applied to the target by a known structure. In this embodiment, a gas supply section (not shown) that supplies a predetermined reactive gas and carrier gas to the target at a predetermined flow rate, and a known magnetic field source (not shown) that forms a magnetic field on the surface of the target are provided near the target.

[0083] The target material, as well as the type and flow rate of the reactive gas, are appropriately determined according to the composition of the adhesion layer 13, high refractive index layer 14a, and low refractive index layer 14b formed on the transparent substrate 11 by passing between the film formation section 41 and the film formation roll 25. For example, SiO ２ When forming a layer consisting of the above, Si is used as the target and O is used as the reactive gas. ２ Use Nb. Also, for example, ２ O ５ When forming a layer consisting of Nb or niobium oxide (NbOx) as the target, O is used as the reactive gas. ２ The low refractive index layer 14b is preferably deposited under a vacuum of less than 0.5 Pa, and the high refractive index layer 14a is preferably deposited under a vacuum of less than 1.0 Pa. When these layers are deposited under these vacuum conditions, the optical functional layer 14 becomes denser, the water vapor transmittance decreases, and durability and other properties are improved.

[0084] In this embodiment, from the viewpoint of increasing the film deposition rate, it is preferable to use the magnetron sputtering method as the sputtering method. However, the sputtering method is not limited to the magnetron sputtering method, and a two-electrode sputtering method that utilizes plasma generated by DC glow discharge or high frequency, or a three-electrode sputtering method that adds a hot cathode may also be used.

[0085] The sputtering apparatus 1 includes an optical monitor (not shown) as a measurement unit for measuring optical properties after each layer, which will become the adhesion layer 13 and the optical functional layer 14, has been formed. This allows for confirmation of the quality of the formed adhesion layer 13 and optical functional layer 14. If the sputtering apparatus 1 has, for example, two or more chambers, it is preferable to install an optical monitor in each chamber.

[0086] An example of an optical monitor (not shown) is one that measures the optical properties in the width direction of the adhesion layer 13 and the optical functional layer 14 formed on the hard coat layer 12 using an optical head that can scan in the width direction. When such an optical monitor is provided, for example, the optical thickness distribution in the width direction of the adhesion layer 13 and the optical functional layer 14 can be measured by measuring the peak wavelength of reflectance as an optical property and converting it to optical thickness. By measuring the optical properties using the optical monitor, it is possible to form an optical laminate 10 having an adhesion layer 13 and an optical functional layer 14 with optimal optical properties while adjusting the sputtering conditions in real time.

[0087] <Pretreatment device 2B> The pretreatment device 2B shown in Figure 3 comprises a chamber 32 with a predetermined reduced pressure atmosphere inside, a can roll 26, a plurality (two in Figure 3) of guide rolls 22, and a plasma discharge device 42. As shown in Figure 3, the can roll 26, the guide rolls 22, and the plasma discharge device 42 are installed inside the chamber 32. As shown in Figure 3, the chamber 32 is connected to the chamber 33 of the deposition device 3.

[0088] The can roll 26 and guide roll 22 transport the transparent substrate 11, on which each layer up to the optical functional layer 14 has been formed, from the sputtering apparatus 1, at a predetermined transport speed, and send the transparent substrate 11 with the surface of the optical functional layer 14 treated to the deposition apparatus 3. As the plasma discharge apparatus 42, for example, one similar to the pretreatment apparatus 2A can be used.

[0089] <Evaporation Apparatus> The evaporation apparatus 3 shown in Figure 3 comprises a chamber 33 whose interior is kept in a predetermined reduced-pressure atmosphere, one or more vacuum pumps 21 (one in Figure 3) that discharge the gas from the chamber 33 to create a reduced-pressure atmosphere, a plurality of guide rolls 22 (four in Figure 3), an evaporation source 43, and a heating device 53. As shown in Figure 3, the guide rolls 22 and the evaporation source 43 are installed inside the chamber 33. The chamber 33 is connected to the chamber 35 of the roll winding device 5.

[0090] The vapor deposition source 43 is positioned opposite the transparent substrate 11, whose surface has been treated with an optical functional layer 14, and which is being conveyed substantially horizontally between two adjacent guide rolls 22. The vapor deposition source 43 supplies an evaporated gas consisting of the material that will become the antifouling layer 15 onto the optical functional layer 14. The orientation of the vapor deposition source 43 can be set arbitrarily. The heating device 53 heats the material that will become the antifouling layer 15 to its vapor pressure temperature. As the heating device 53, a resistance heating method, a heater heating method, an induction heating method, or an electron beam heating method can be used. In the resistance heating method, the container containing the antifouling material that will become the antifouling layer 15 is heated by current as a resistor. In the heater heating method, the container is heated by a heater placed on the outer circumference of the container. In the induction heating method, the container or the antifouling material is heated by electromagnetic induction from an induction coil installed externally.

[0091] The deposition apparatus 3 shown in Figure 3 includes a guide plate (not shown) for guiding the deposition material evaporated by the deposition source 43 to a predetermined position, a film thickness gauge (not shown) for observing the thickness of the antifouling layer 15 formed by deposition, a vacuum pressure gauge (not shown) for measuring the pressure inside the chamber 33, and a power supply (not shown). The guide plate may have any shape as long as it can guide the evaporated deposition material to the desired position. The guide plate does not need to be provided if it is not necessary. For example, an ion gauge can be used as the vacuum pressure gauge. For example, a high-frequency power supply can be used as the power supply.

[0092] <Roll Winding Device> The roll winding device 5 shown in Figure 3 comprises a chamber 35 whose interior is kept in a predetermined reduced-pressure atmosphere, one or more vacuum pumps 21 (one in Figure 3) that discharge the gas from the chamber 35 to create a reduced-pressure atmosphere, and a winding roll 24 and a guide roll 22 installed inside the chamber 35. A transparent substrate 11 (optical laminate 10) with each layer up to the anti-fouling layer 15 formed on its surface is wound around the winding roll 24. The winding roll 24 and the guide roll 22 wind the optical laminate 10 at a predetermined winding speed. A carrier film may also be used if necessary.

[0093] The vacuum pump 21 provided in the manufacturing apparatus 20 shown in Figure 3 can be, for example, a dry pump, an oil rotary pump, a turbomolecular pump, an oil diffusion pump, a cryopump, a sputter ion pump, or a getter pump. The vacuum pump 21 can be appropriately selected or used in combination in each of the chambers 31, 32, 33, 34, and 35 to create the desired reduced pressure state.

[0094] The vacuum pump 21 only needs to be able to maintain both the chamber 31 of the sputtering apparatus 1 and the chamber 33 of the deposition apparatus 3 in a desired reduced pressure state, and the installation location and number of vacuum pumps 21 in the manufacturing apparatus 20 are not particularly limited. In addition, in the manufacturing apparatus 20 shown in Figure 3, the roll unwinding device 4, the pretreatment device 2A, the sputtering apparatus 1, the pretreatment device 2B, the deposition apparatus 3, and the roll winding device 5 are connected. For this reason, the vacuum pump 21 may be installed in each of the chambers 31, 32, 33, 34, and 35, or it may be installed in only some of the chambers 31, 32, 33, 34, and 35, as long as it can maintain both the chamber 31 of the sputtering apparatus 1 and the chamber 33 of the deposition apparatus 3 in a desired reduced pressure state.

[0095] Next, a method will be described for continuously performing the first surface treatment process, the adhesion layer formation process, the optical functional layer formation process, the second surface treatment process, and the antifouling layer formation process using the manufacturing apparatus 20 shown in Figure 3, while maintaining the optical laminate 10 in the process of being manufactured under reduced pressure. First, an unwinding roll 23, around which a transparent substrate 11 with a hard coat layer 12 formed on its surface is wound, is placed in the chamber 34 of the roll unwinding device 4. Then, the unwinding roll 23 and the guide roll 22 are rotated to feed the transparent substrate 11 with the hard coat layer 12 formed on its surface to the pretreatment device 2A at a predetermined transport speed.

[0096] Next, a first surface treatment step is performed in the chamber 32 of the pretreatment apparatus 2A as a pretreatment for the surface on which the adhesion layer 13 and the optical functional layer 14 will be formed. In this embodiment, the first surface treatment step is performed on the transparent substrate 11 on which the hard coat layer 12 is formed. In the first surface treatment step, the can roll 26 and the guide roll 22 are rotated to transport the transparent substrate 11 on which the hard coat layer 12 is formed at a predetermined transport speed, while the surface of the hard coat layer 12 running on the can roll 26 is treated.

[0097] For example, glow discharge treatment, plasma treatment, ion etching, and alkaline treatment can be used as surface treatment methods for the hard coat layer 12. As mentioned above, among these, glow discharge treatment is preferred because it allows for large-area treatment.

[0098] Next, the adhesion layer formation process and the optical functional layer formation process are performed in the chamber 31 of the sputtering apparatus 1. Specifically, the film formation roll 25 and the guide roll 22 are rotated to transport the transparent substrate 11 on which the hard coat layer 12 has been formed at a predetermined transport speed, and the adhesion layer 13 and the optical functional layer 14 are formed on the hard coat layer 12 as it travels on the film formation roll 25.

[0099] In this embodiment, an adhesion layer 13 is formed by sputtering while changing the target material installed in each film deposition section 41, or the type and flow rate of reactive gas supplied from the gas supply section, and a high refractive index layer 14a and a low refractive index layer 14b are alternately laminated on top of it. That is, the adhesion layer formation process and the optical functional layer formation process are performed continuously within the sputtering apparatus 1. This forms the adhesion layer 13 and the optical functional layer 14, which is an anti-reflective layer. The high refractive index layer 14a and the low refractive index layer 14b are each deposited under conditions below a predetermined vacuum level. Specifically, the high refractive index layer 14a is deposited at a vacuum level of less than 1.0 Pa, and the low refractive index layer 14b is deposited at a vacuum level of less than 0.5 Pa.

[0100] When forming a SiOx film as the adhesion layer 13, it is preferable to form it using a silicon target and reactive sputtering in a mixed gas atmosphere of oxygen and argon. When continuously stacking the adhesion layer 13, the high refractive index layer 14a, and the low refractive index layer 14b by sputtering, the target material may be changed during the formation of the adhesion layer 13, the high refractive index layer 14a, and the low refractive index layer 14b. Alternatively, for example, one type of material may be used as the target, and by changing the oxygen (reactive gas) flow rate during sputtering, layers made of the target material and layers made of oxides of the target material may be alternately formed, forming the adhesion layer 13, the high refractive index layer 14a, and the low refractive index layer 14b.

[0101] The pressure used during sputtering to form the adhesion layer 13 and the optical functional layer 14 varies depending on the metal being sputtered, but may be 2 Pa or less, preferably 1 Pa or less, more preferably 0.6 Pa or less, and particularly preferably 0.2 Pa or less. When sputtering is performed under reduced pressure of 1 Pa or less, the mean free path of the film-forming molecules becomes longer, and the films are layered while the energy of the film-forming molecules remains high, resulting in a denser and better film quality. It is preferable that the sputtering pressures for the high refractive index layer and the low refractive index layer be different, because the mean free path differs for each type of film. By changing the pressure for each type of film, a denser film can be formed.

[0102] Subsequently, the transparent substrate 11, on which the adhesion layer 13 and the optical functional layer 14 are formed on the hard coat layer 12, is fed to the pretreatment device 2B by the rotation of the film-forming roll 25 and the guide roll 22. Next, a second surface treatment step is performed in the chamber 32 of the pretreatment device 2B as a pretreatment for the surface on which the antifouling layer 15 will be formed. In this embodiment, the transparent substrate 11 on which the optical functional layer 14 has been formed, obtained in the optical functional layer formation step, is continuously subjected to the second surface treatment step while being maintained under reduced pressure without being exposed to the atmosphere. In the second surface treatment step, the can roll 26 and the guide roll 22 are rotated to transport the transparent substrate 11, on which each layer up to the optical functional layer 14 has been formed, at a predetermined transport speed, and a discharge treatment is performed on the surface of the optical functional layer 14 as it travels on the can roll 26.

[0103] For example, glow discharge treatment, plasma treatment, ion etching, and alkaline treatment can be used as surface treatment methods for the optical functional layer 14. Among these, glow discharge treatment is preferred because it allows for large-area treatment.

[0104] When an electrical discharge treatment is performed on the surface of the optical functional layer 14, the surface of the optical functional layer 14 is etched, and the surface state of the optical functional layer 14 changes. The surface state of the optical functional layer 14 is expressed by the surface roughness Ra or the average element length RSm. For example, in the case of a clear type anti-reflective film with a haze value of 2.0% or less, the surface state of the optical functional layer 14 is easily defined by the surface roughness Ra. Also, for example, in the case of an AG type anti-reflective film with a haze value of more than 2.0%, the surface state of the optical functional layer 14 is easily defined by the average element length RSm. The surface roughness Ra and the average element length RSm are measured in accordance with JIS B0601 (ISO 4287).

[0105] Subsequently, the transparent substrate 11 with the surface of the optical functional layer 14 treated is fed to the deposition apparatus 3 by the rotation of the can roll 26 and guide roll 22. Next, the antifouling layer formation process is performed in the chamber 33 of the deposition apparatus 3. In this embodiment, the transparent substrate 11 with the surface of the optical functional layer 14 treated in the second surface treatment process is continuously subjected to the antifouling layer formation process while being maintained under reduced pressure without being exposed to the atmosphere. In the antifouling layer formation process, the guide roll 22 is rotated to transport the transparent substrate 11 with the surface of the optical functional layer 14 treated at a predetermined transport speed, while the deposition source 43 is deposited on the surface of the optical functional layer 14.

[0106] In this embodiment, for example, an antifouling material made of a fluorine-based organic compound that will become the antifouling layer 15 is heated to its vapor pressure temperature by a heating device 53, and the resulting evaporated gas is supplied from a deposition source 43 under a reduced pressure environment and deposited onto the surface-treated optical functional layer 14 to form the antifouling layer 15 by vacuum deposition. The pressure when performing vacuum deposition of the antifouling layer 15 is preferably 0.05 Pa or less, more preferably 0.01 Pa or less, and particularly preferably 0.001 Pa or less. When the pressure during vacuum deposition is a reduced pressure of 0.05 Pa or less, the mean free path of the film-forming molecules is long and the deposition energy is high, so a denser and better antifouling layer 15 can be obtained.

[0107] By the above method, an optical laminate 10 is obtained in which an antifouling layer 15 is formed by vacuum deposition on an adhesion layer 13 and an optical functional layer 14 formed by sputtering.

[0108] Subsequently, the transparent substrate 11 (optical laminate 10), on which each layer up to the anti-fouling layer 15 has been formed, is fed to the roll winding device 5 by the rotation of the guide roll 22. Then, within the chamber 35 of the roll winding device 5, the optical laminate 10 is wound onto the winding roll 24 by the rotation of the winding roll 24 and the guide roll 22.

[0109] In this embodiment, it is preferable to perform the optical functional layer formation process and the antifouling layer formation process continuously under reduced pressure. In particular, when the optical laminate 10 is continuously manufactured as a roll-to-roll roll, as in the manufacturing method of this embodiment using the manufacturing apparatus 20 shown in Figure 3, it is even more preferable to perform the optical functional layer formation process and the antifouling layer formation process continuously in line while maintaining a reduced pressure state. In line means performing the antifouling layer formation process without exposing the optical functional layer 14 formed in the optical functional layer formation process to the atmosphere. By performing the optical functional layer formation process and the antifouling layer formation process continuously under reduced pressure, the formation of a natural oxide film on the optical functional layer 14 formed in the optical functional layer formation process before the antifouling layer 15 is formed is suppressed. In addition, contamination such as foreign matter when winding the roll can be prevented from adhering to the optical functional layer 14 and hindering the adhesion between the optical functional layer 14 and the antifouling layer 15. Therefore, compared to the case where, after the optical functional layer formation process, the transparent substrate 11 on which each layer up to the optical functional layer 14 is formed is removed from the chamber under reduced pressure, and then placed back into the chamber to perform the antifouling layer formation process under reduced pressure, the adhesion between the optical functional layer 14 and the antifouling layer 15 is good, and an optical laminate with excellent transparency can be obtained.

[0110] Furthermore, since the antifouling layer 15 of the optical laminate 10 in this embodiment is a vapor-deposited film, it exhibits higher abrasion resistance compared to, for example, an antifouling film formed by a coating method. This is presumed to be due to the following reasons: In antifouling films formed by a coating method, there are voids caused by the solvent contained in the paint. In contrast, vapor-deposited films do not have voids caused by the solvent. For this reason, vapor-deposited films are denser than antifouling films formed by a coating method, and are presumed to exhibit higher abrasion resistance and alkali resistance.

[0111] The manufacturing method for the optical laminate 10 of this embodiment includes an adhesion layer formation step of forming an adhesion layer 13, an optical functional layer formation step of forming an optical functional layer 14 by alternately laminating a high refractive index layer 14a and a low refractive index layer 14b, a second surface treatment step of treating the surface of the optical functional layer 14, and an antifouling layer formation step of forming an antifouling layer 15 on the surface-treated optical functional layer 14. As a result, the adhesion between the optical functional layer 14 and the antifouling layer 15 formed on the optical functional layer 14 is good, and the friction resistance and alkali resistance are further improved.

[0112] In this embodiment, when the first surface treatment step, the optical functional layer formation step, the second surface treatment step, and the antifouling layer formation step are performed continuously while maintaining the optical laminate under reduced pressure during manufacturing, the reduced pressure conditions in the chambers of, for example, the sputtering apparatus and the deposition apparatus may differ, as long as they do not interfere with each manufacturing step.

[0113] In this embodiment, it is preferable to measure the film formation results over time using a measuring instrument in one or more of the following steps: the adhesion layer formation step, the optical functional layer formation step, and the antifouling layer formation step, and to feed the results back into the conditions of the subsequent manufacturing step. This makes it easier to optimize the characteristics of the entire optical laminate and makes the in-plane characteristics of the optical laminate uniform. It is also possible to feed back the manufacturing conditions in the same step using the measuring instrument. In this case, the layer formed in that step will have uniform and stable characteristics.

[0114] In this embodiment, the case in which a second surface treatment step is performed between the optical functional layer formation step and the antifouling layer formation step has been described as an example, but the second surface treatment step may be performed as needed or may not be performed at all. Even if the second surface treatment step is not performed, it is preferable to perform the optical functional layer formation step and the antifouling layer formation step continuously under reduced pressure.

[0115] Furthermore, in the manufacturing method of this embodiment, the optical functional layer is formed under conditions below a predetermined vacuum level. As a result, the optical functional layer 14 becomes denser, the water vapor permeability decreases, and the abrasion resistance and alkali resistance improve. In addition, by ensuring that the film thickness of the antifouling layer is greater than or equal to a predetermined thickness, sufficient scratch resistance and alkali resistance can be secured.

[0116] In this embodiment, the manufacturing apparatus 20 shown in Figure 3, which includes a pretreatment device 2A, a sputtering device 1, a pretreatment device 2B, a vapor deposition device 3, a roll unwinding device 4, and a roll winding device 5, was described as an example of continuously manufacturing an optical laminate 10 using a roll-to-roll method. However, the manufacturing apparatus for manufacturing the optical laminate 10 is not limited to the manufacturing apparatus 20 shown in Figure 3. For example, a manufacturing apparatus may be used that does not include the pretreatment devices 2A and 2B, but in which the roll unwinding device 4, the sputtering device 1, the vapor deposition device 3, and the roll winding device 5 are connected in that order.

[0117] The manufacturing apparatus 20 shown in Figure 3 may include a pre-treatment chamber (not shown) between the chamber 33 of the deposition apparatus 3 and the chamber 32 of the pre-treatment apparatus 2B for cleaning the surface of the optical functional layer 14 on which the antifouling layer 15 is formed. The manufacturing apparatus 20 shown in Figure 3 may also include a post-treatment chamber (not shown) between the chamber 33 of the deposition apparatus 3 and the chamber 35 of the roll winding apparatus 5 for cooling and / or inspecting the transparent substrate 11 on which each layer up to the antifouling layer 15 is formed.

[0118] The manufacturing apparatus 20 shown in Figure 3 may include a hard coat layer forming apparatus between the roll unwinding apparatus 4 and the sputtering apparatus 1 for forming a hard coat layer 12 on the surface of the transparent substrate 11. In this case, not only the optical functional layer 14 and the antifouling layer 15, but also the hard coat layer 12 can be manufactured continuously using a roll-to-roll method, which is preferable.

[0119] In this embodiment, the example described was that the optical functional layer formation process is performed using a sputtering apparatus and the antifouling layer formation process is performed using a vapor deposition apparatus. However, if the second surface treatment process is not performed, the optical functional layer formation process and the antifouling layer formation process may be performed in the same apparatus (in one chamber).

[0120] In the optical laminate 10 of this embodiment, various layers may be provided on the surface facing the surface on which the optical functional layer of the transparent substrate is formed, as needed. For example, an adhesive layer used for bonding with other components may be provided. Alternatively, another optical film may be provided via this adhesive layer. Examples of other optical films include polarizing films, phase difference compensation films, films that function as half-wave plates or quarter-wave plates.

[0121] Furthermore, a layer having functions such as anti-reflection, selective reflection, anti-glare, polarization, phase difference compensation, viewing angle compensation or expansion, light guidance, diffusion, brightness enhancement, hue adjustment, and conductivity may be directly formed on the opposing surface of the transparent substrate.

[0122] The article of this embodiment is provided with the above-described optical laminate 10 on the display surface of an image display unit, such as a liquid crystal display panel or an organic EL display panel. This makes it possible to provide high abrasion resistance and alkali resistance to the touch panel display unit of a smartphone or operating device, for example, and realize an image display device that is highly durable and suitable for practical use.

[0123] Furthermore, the object is not limited to an image display device; for example, any object to which the optical laminate 10 can be applied is acceptable, such as glass or goggles with the optical laminate of this embodiment on its surface, the light-receiving surface of a solar cell, the screen of a smartphone or a display for a notebook PC, an information input terminal, a tablet terminal, an AR (augmented reality) device, a VR (virtual reality) device, an electronic display board, a table surface, amusement machines, operation support devices for aircraft or trains, a navigation system, an instrument panel, or the surface of an optical sensor.

[0124] Figure 4 is a schematic diagram illustrating an example of an article equipped with the optical laminate of this embodiment. As shown in Figure 4, the terminal 60 comprises a housing 61, an image display unit 62 provided on the housing 61, and an optical laminate 10 provided on the surface of the image display unit 62. The terminal 60 has a bendable portion 63 and is configured to rotate about an axis B along the width direction of the housing 61 such that the surface A on which the image display unit 62 and the optical laminate 10 are provided faces inward. The terminal 60 is not particularly limited, but for example, it could be a touch panel type smartphone.

[0125] Although embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. For example, an anti-glare layer can be formed instead of the hard coat layer 12, or any functional layer can be added as needed, such as a flexible soft coat layer. These may be laminated.

[0126] The following describes embodiments of the present invention. Note that the optical laminates created in the following embodiments and comparative examples are examples of structures that function as anti-reflective films, and the spirit of the present invention is not limited to these.

[0127] <Preparation of composition for hard coat layer> First, a photocurable composition 1 was prepared such that the content of silica particles with an average particle size of 80 nm (particle size distribution of 75-85 nm) was 29% by mass of the total solid content of the composition. Composition 1 was prepared by dissolving acrylate (binder resin), silica particles, and a photopolymerization initiator in a solvent, as shown in Table 1, and then adding a leveling agent.

[0128]

[0129] CN968: Hexafunctional aliphatic urethane acrylate with a polyester backbone SR610: Polyethylene glycol diacrylate, average molecular weight of polyethylene glycol chain 600 PGM-AC-4130Y: Surface-modified silica sol with methacryloyl group-containing silane compound, dispersion medium propylene glycol monomethyl ether MEK-AC-5140Y: Surface-modified silica sol with methacryloyl group-containing silane compound, dispersion medium methyl ethyl ketone IPA-ST-L: Silica sol (unmodified), dispersion medium isopropyl alcohol Ominirad 184: 1-Hydroxycyclohexylphenyl ketone

[0130] (Example 1) A PET film with a thickness of 50 μm was used as a transparent substrate. Composition 1 was applied to this PET film using a bar coater, and then composition 1 was photopolymerized to form a hard coat layer with a thickness of 5 μm on the transparent substrate.

[0131] Next, the surface of the hard coat layer was subjected to an electrode power density of 5500 W / m². ２ The surface was treated by glow discharge treatment. Subsequently, on the hard coat layer, a Si target and an Nb target were used as sputtering targets, and Ar gas and O ２ An adhesion layer and an optical functional layer were continuously formed by reactive sputtering using a gas mixture. Specifically, an adhesion layer made of oxygen-deficient Si oxide (SiOx, 0 < x < 2) with a thickness of 3 nm and an Nb layer with a thickness of 10 nm were formed on the hard coat layer. ２ O ５ A first high refractive index layer consisting of and a 26 nm thick SiO ２ A first low refractive index layer consisting of and a 110 nm thick Nb ２ O ５ A second high refractive index layer consisting of and a SiO layer with a thickness of 85 nm ２ A second low refractive index layer consisting of the above was deposited in this order.

[0132] Next, with a deposition chamber pressure of 0.01 Pa, a deposition temperature of 230°C, and a holding time of 7.2 s, the SiO2 layer at the top of the optical functional layer was deposited. ２A 3 nm thick antifouling layer made of an alkoxysilane compound having a perfluoropolyether group (KY1903-1, manufactured by Shin-Etsu Chemical Co., Ltd.) was formed on the film by vacuum deposition to produce the optical laminate (anti-reflective film) of the example.

[0133] (Example 2) An optical laminate was obtained in the same manner as in Example 1, except that a photocurable composition 2 was prepared such that the content of silica particles with an average particle diameter of 80 nm (particle size distribution of 75 nm to 85 nm) was 48% by mass relative to the total solid content of the composition.

[0134] (Example 3) An optical laminate was obtained in the same manner as in Example 1, except that a photocurable composition 3 was prepared such that the content of silica particles with an average particle size of 80 nm (particle size distribution of 75 nm to 85 nm) was 24% by mass relative to the total solid content of the composition, and the content of silica particles (filler) with an average particle size of 45 nm (particle size distribution of 40 nm to 50 nm) was 24% by mass relative to the total solid content of the composition.

[0135] (Example 4) An optical laminate was obtained in the same manner as in Example 1, except that a photocurable composition 4 was prepared such that the content of silica particles with an average particle size of 80 nm (particle size distribution of 75 nm to 85 nm) was 10% by mass relative to the total solid content of the composition, and the content of silica particles with an average particle size of 45 nm (particle size distribution of 40 nm to 50 nm) was 38% by mass relative to the total solid content of the composition.

[0136] (Example 5) An optical laminate was obtained in the same manner as in Example 1, except that a photocurable composition 5 was prepared such that the content of silica particles with an average particle size of 80 nm (particle size distribution of 75 nm to 85 nm) was 19% by mass of the total solid content of the composition, and the content of silica particles with an average particle size of 45 nm (particle size distribution of 40 nm to 50 nm) was 29% by mass of the total solid content of the composition.

[0137] (Example 6) An optical laminate was obtained in the same manner as in Example 1, except that a photocurable composition 6 was prepared such that the content of silica particles with an average particle size of 80 nm (particle size distribution of 75 nm to 85 nm) was 29% by mass of the total solid content of the composition, and the content of silica particles with an average particle size of 45 nm (particle size distribution of 40 nm to 50 nm) was 19% by mass of the total solid content of the composition.

[0138] (Example 7) An optical laminate was obtained in the same manner as in Example 1, except that a photocurable composition 7 was prepared such that the content of silica particles with an average particle size of 80 nm (particle size distribution of 75-85 nm) was 39% by mass of the total solid content of the composition, and the content of silica particles with an average particle size of 45 nm (particle size distribution of 40-50 nm) was 10% by mass of the total solid content of the composition.

[0139] (Comparative Example 1) An optical laminate was obtained in the same manner as in Example 1, except that composition 1, which forms the hard coat layer, was changed to composition 8 shown in Table 1.

[0140] Next, the optical laminates obtained in Examples 1 to 7 and Comparative Example 1 were measured and evaluated using the following methods.

[0141] <Bending Test> As a sample, an optical laminate cut to 1 cm x 15 cm was prepared. It was confirmed that there were no cracks on the cut surface of the optical laminate. (Mandrel Test) A 5.0 mm mandrel was set in a bending test machine that can accommodate a mandrel. The aforementioned optical laminate was set in this test machine so that the side with the antifouling layer formed on it was bent inward. Then, the test machine was bent over 2 seconds to bend the optical laminate 180° and held for 10 seconds. After that, the presence or absence of cracks in the antifouling layer was checked visually and with an optical microscope. The above procedure was repeated while changing the mandrel diameter to a smaller one by 0.2 mm increments until any abnormalities such as cracks were observed on the surface of the antifouling layer of the optical laminate visually and with an optical microscope. The diameter (φ mm) of the mandrel that was 0.2 mm larger than the diameter of the mandrel in which the first crack was found was taken as the test result of the bending test.

[0142] Furthermore, the theoretical elongation rate S (%) of the optical functional layer was calculated using the smallest diameter mandrel that did not exhibit cracking during the mandrel test. The elongation rate S was calculated as follows: S (%) = {(R2 / R1) - 1} × 100 (where R2 is the distance from the axis center of the mandrel to the outer surface of the optical laminate, and R1 is the distance from the axis center of the mandrel to a virtual line indicating a position corresponding to half the total thickness of the optical laminate.)

[0143] (Unloaded U-shaped test) An optical laminate was horizontally stretched and attached to a pair of tilt clamps (parallel plates) using a planar unloaded U-shaped stretch test machine (manufactured by Yuasa System Equipment Co., Ltd., device name "DMLHB / DMX-FSB"), and set so that the surface with the antifouling layer was bent inward. The optical laminate was bent 180° at an average bending speed of 2 cm / second and held for 10 seconds. After that, the presence or absence of cracks on the surface with the antifouling layer was checked visually and with an optical microscope. The distance between the pair of tilt clamps was gradually reduced until cracks or other abnormalities were observed on the surface with the antifouling layer of the optical laminate visually and with an optical microscope. The distance between the clamps (distance between the flat plates) when the first crack was discovered was taken as the test result of the bending test.

[0144] Furthermore, in an unloaded U-shaped test, the theoretical compression ratio C (%) of the optical functional layer was calculated when the surface with the antifouling layer was set to be bent inward, and the layer was bent to the minimum bending radius at which no cracks occurred. The compression ratio C was calculated as follows: C (%) = {1 - (R3 / R1)} × 100 (where R3 is the distance obtained by subtracting the thickness of the optical laminate from half the distance between the flat plates, and R1 is the distance obtained by subtracting half the thickness of the optical laminate from half the distance between the flat plates.)

[0145] For each measurement, three samples were prepared, and each value was calculated from the average of the three measurements.

[0146] <Martens Hardness> Laminates (samples) were prepared using compositions 1 to 7, each consisting of a hard coat layer formed on a transparent substrate. For the optical laminates obtained in Examples 1 to 7 and Comparative Example 1, the Martens hardness of the antifouling layer side of the optical laminate was measured. For the laminates with only a hard coat layer, the Martens hardness of the hard coat layer side of the laminate was measured. For the measurements, a microcompression tester (ENT-NEXUS, manufactured by Elionix Corporation, measuring indenter: Berkovich indenter) was used in accordance with ISO 14577-1. For the optical laminates, the hardness at an indentation depth of 50 nm was determined, and for the laminates with only a hard coat layer, the hardness at a depth of 1 / 10 of the hard coat layer thickness was determined. Furthermore, the Martens hardness of the optical laminates measured above was denoted as (A), and the Martens hardness of the laminates with only a hard coat layer formed on a transparent substrate was denoted as (B), and the ratio (A) / (B) was calculated. The results are shown in Table 2.

[0147] Furthermore, the optical laminates obtained in Examples 1 to 7 and Comparative Example 1 were measured and evaluated using the following methods.

[0148] <Contact Angle Measurement Test with Pure Water> A fully automatic contact angle meter DM-700 (manufactured by Kyowa Interface Chemical Co., Ltd.) was used to measure the contact angle using the elliptic fitting method under the following conditions. Pure water was placed in a glass syringe, a stainless steel needle was attached to the tip, and the pure water was dropped onto the optical laminate (test piece). Amount of pure water dropped: 2.0 μL Measurement temperature: 25°C The contact angle was measured at six arbitrary locations on the surface of the test piece one second after the pure water was dropped onto the laminate (sample), and the average value was taken as the pure water contact angle.

[0149] <Steel Wool Sliding Test> Using a Type I friction tester compliant with JIS L0849, a friction element was moved horizontally back and forth along the surface of an optical laminate (test specimen) to obtain a test specimen. Steel wool (Bonstar Co., Ltd., #0000 grade) was used as the friction element. The test setting was a load of 1000 g / cm². ２The sliding distance was set to 50 mm, the sliding speed to 60 rpm (1 cycle / second), and the number of sliding cycles to 200 (100 cycles). After sliding, the same test as the contact angle measurement test for pure material described above was performed on the sample, and the difference in contact angle before and after the test was determined. The results are shown in Table 2.

[0150]

[0151] From the results in Table 2, it was found that in all of Examples 1 to 7, the hard coat layer contained silica particles (A) with an average particle size of 80 nm, and the ratio ((A) / (B)) of the Martens hardness (A) on the antifouling layer side of the optical laminate to the Martens hardness (B) on the hard coat layer side of the laminate having only a transparent substrate and a hard coat layer was 3.65 or less, indicating that excellent hardness could be achieved while further improving flexibility. In particular, it was found that the silica particles contained in the hard coat layer were surface-modified with methacryloyl groups derived from a methacryloyl group-containing silane compound, which is thought to have resulted in a stronger bond between the methacryloyl groups and the acrylate (binder resin), thereby improving the hardness of the optical laminate. Furthermore, it was found that the methacryloyl groups on the surface of the silica particles further improved the adhesion between the hard coat layer and the adhesion layer, and between the optical functional layer via the adhesion layer, further improving flexibility. Furthermore, in all of Examples 1 to 7, the difference in contact angle with water before friction and after friction by 200 horizontal reciprocating motions of the steel wool was 20° or less. This suggests that the silica particles contained in the hard coat layer are surface-modified with methacryloyl groups derived from methacryloyl group-containing silane compounds, resulting in stronger bonding of the methacryloyl groups to the acrylate (binder resin). As a result, the hardness of the optical laminate is improved, and excellent scratch resistance can be achieved.

[0152] Furthermore, in Examples 3 to 7, it was found that when the hard coat layer contains silica particles (A) with an average particle diameter of 80 nm and silica particles (B) with an average particle diameter of 45 nm, the haze value is reduced and high transparency is achieved while maintaining the same hardness, flexibility, and scratch resistance as in Examples 1 and 2, where the hard coat layer contains only silica particles (A) with an average particle diameter of 80 nm.

[0153] On the other hand, in Comparative Example 1, when a hard coat layer was formed using composition 8 containing unmodified silica particles with an average particle size of 45 nm, the above ratio ((A) / (B)) became 3.71, resulting in a lower hardness of the laminate. Furthermore, the compression ratio C (internal bending) was 4.4, indicating poor bending resistance. In addition, the contact angle difference before and after the steel wool sliding test was 21.8°, indicating poor scratch resistance.

[0154] 10, 102... Optical laminate 11... Transparent substrate 12... Hard coat layer 13... Adhesion layer 14... Optical functional layer 14a... High refractive index layer 14b... Low refractive index layer 15... Antifouling layer 20... Manufacturing equipment 1... Sputtering equipment 2A, 2B... Pretreatment equipment 3... Evaporation equipment 4... Roll unwinding equipment 5... Roll winding equipment 20... Manufacturing equipment 21... Vacuum pump 22... Guide roll 23... Unwinding roll 24... Winding roll 25... Film deposition roll 26... Can roll 31, 32, 33, 34, 35... Chamber 41... Film deposition section 42... Plasma discharge equipment 43... Evaporation source 53... Heating equipment 60... Terminal 61... Housing 62... Image display section 63... Bending section

Claims

1. An optical laminate having a transparent substrate, a hard coat layer, an optical functional layer including an anti-reflective layer, and an anti-fouling layer in this order, wherein the hard coat layer contains silica particles (A) with an average particle diameter of 65 nm or more, and satisfies the following conditions 1 and 2. Condition 1: The ratio ((A) / (B)) of the Martens hardness (A) measured from the anti-fouling layer side of the optical laminate to the Martens hardness (B) measured from the hard coat layer side of a laminate having only the transparent substrate and the hard coat layer is 3.65 or less. Condition 2: Using a friction tester with steel wool conforming to JIS L0849, the difference in contact angle with water before friction and after friction by moving the steel wool horizontally back and forth 200 times is 20° or less.

2. The optical laminate according to claim 1, wherein the silica particles (A) are surface-modified with functional groups derived from a silane compound.

3. The optical laminate according to claim 1, wherein the hard coat layer further contains silica particles (B) with an average particle diameter of 55 nm or less.

4. The optical laminate according to claim 3, wherein the silica particles (B) are surface-modified with functional groups derived from a silane compound.

5. The optical laminate according to claim 2 or 4, wherein the silane compound is one or more selected from vinyl group-containing silane compounds, (meth)acryloyl group-containing silane compounds, amino group-containing silane compounds, isocyanate group-containing silane compounds, isocyanurate group-containing silane compounds, epoxy group-containing silane compounds, and mercapto group-containing silane compounds.

6. The optical laminate according to claim 5, wherein the silane compound is a (meth)acryloyl group-containing silane compound.

7. The optical laminate according to claim 2, wherein the hard coat layer contains a binder resin and silica particles (A), and the functional group derived from the silane compound has the same functional group as the binder resin.

8. The optical laminate according to claim 4, wherein the hard coat layer contains a binder resin, silica particles (A), and silica particles (B), and the functional group derived from the silane compound has the same functional group as the binder resin.

9. The optical laminate according to claim 7 or 8, wherein the binder resin contains a (meth)acrylate compound, and the functional group derived from the silane compound is a (meth)acryloyl group.

10. The optical laminate according to claim 1, wherein the thickness of the hard coat layer is 0.5 μm or more and 100 μm or less.

11. The optical laminate according to claim 1, wherein the optical functional layer includes a high refractive index layer and a low refractive index layer having a lower refractive index than the high refractive index layer.

12. The optical laminate according to claim 1, wherein when the optical laminate is bent 180° using a planar body unloaded U-shaped stretch tester with the surface on which the antifouling layer is formed facing inward, the compression ratio C (%) of the optical functional layer, calculated by the following formula (2), satisfies 4.5 ≤ C when the laminate is bent to the smallest bending radius without cracking, and C (%) = {1 - (R3 / R1)} × 100 ... (2) (wherein R3 is the distance obtained by subtracting the thickness of the optical laminate from half the distance between the flat plates, and R1 is the distance obtained by subtracting half the thickness of the optical laminate from half the distance between the flat plates.) 13. An article comprising an optical laminate according to any one of claims 1 or 2.

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