Optical laminate and article including same

Abstract

Provided is an optical laminate that can achieve excellent scratch resistance and further improves bending resistance. [Solution] An optical laminate 102 has, in this order, a transparent substrate 11, a hard coat layer 12, an adhesion layer 13 made of a sputtered film, an optical functional layer 14 formed by alternating high-refractive-index layers made of sputtered films and low-refractive-index layers with a lower refractive index than the high-refractive-index layers, and an antifouling layer 15. The hard coat layer 12 contains a silica filler, and the optical laminate satisfies the following conditions 1 and 2. Condition 1: The ratio ((A) / (B)) of the Martens hardness (A) of the antifouling layer side of the optical laminate to the Martens hardness (B) of the hard coat layer side of a laminate having only the transparent substrate and the hard coat layer is 3.6 or less. Condition 2: Using a friction tester using steel wool in accordance with JIS L0849, the difference in contact angle with water before and after 200 horizontal reciprocating strokes of the steel wool is 20° or less.

Description

[Technical Field]

[0001] The present invention relates to an optical laminate and an article including the same, and particularly to an optical laminate used as an anti-reflection film suitable for displays that are used in a bent state, such as flexible displays, and an article including the same. [Background technology]

[0002] In recent years, mobile communication terminals such as smartphones and information devices such as notebook PCs equipped with foldable displays have been released on the market. Optical laminates such as anti-reflection films are sometimes used in these displays to reduce surface reflection. Optical laminates used in foldable displays are required to have higher durability against bending than non-foldable displays.

[0003] For example, Patent Document 1 proposes that in a hard coat film having a hard coat layer and an optical functional layer consisting of a sputtered film, the thickness ratio of the hard coat layer to the optical functional layer be set within a predetermined range to improve the flex resistance.

[0004] Furthermore, Patent Document 2 describes that bending resistance can be improved by making the hard coat layer and antireflection layer out of resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-189597 [Patent Document 2] Japanese Patent Application Publication No. 2020-74019 Summary of the Invention [Problem to be solved by the invention]

[0006] However, although Patent Document 1 aims to improve the abrasion resistance and flex resistance of the hard coat film, it does not evaluate the scratch resistance, and there is room for improvement. Furthermore, although Patent Document 2 also improves the bending resistance of the antireflection film, the antireflection layer is made of resin, resulting in poor scratch resistance.

[0007] The present invention has been made in consideration of the above problems, and aims to provide an optical laminate that can achieve excellent scratch resistance and further improves bending resistance, and an article including the same. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention proposes the following means. [1] An optical laminate having, in this order, a transparent substrate, a hard coat layer, an adhesion layer made of a sputtered film, a high refractive index layer made of a sputtered film, and an optical function layer in which a low refractive index layer having a refractive index lower than that of the high refractive index layer is alternately laminated, and an antifouling layer, the hard coat layer contains a silica filler, An optical laminate that satisfies the following conditions 1 and 2. Condition 1: The ratio ((A) / (B)) of the Martens hardness (A) measured from the antifouling 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 3.6 or less. Condition 2: Using a friction tester using steel wool conforming to JIS L0849, the difference in contact angle with water before and after 200 horizontal reciprocating movements of the steel wool is 20° or less.

[0009] [2] The optical laminate according to the above [1], wherein the silica filler is surface-modified with a functional group derived from a silane compound.

[0010] [3] The optical laminate according to [2] above, wherein the silane compound is one or more selected from the group consisting of 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.

[0011] [4] The optical laminate according to the above [2], wherein the silane compound is a (meth)acryloyl group-containing silane compound.

[0012] [5] The hard coat layer contains a binder resin and a silica filler, The optical laminate according to [2] above, wherein the functional group derived from the silane compound has the same functional group as the binder resin.

[0013] [6] The binder resin contains a (meth)acrylate compound, The optical laminate according to the above [5], wherein the functional group derived from the silane compound is a (meth)acryloyl group.

[0014] [7] The optical laminate according to the above [1], wherein the average particle diameter of the silica filler is 800 nm or less.

[0015] [8] The optical laminate according to the above [1], wherein the thickness of the hard coat layer is 0.5 μm or more and 100 μm or less.

[0016] [9] The optical laminate described in [1] above, wherein when the optical laminate is bent 180° so that the surface on which the antifouling layer is formed is facing outward, and a mandrel of the smallest diameter on which no cracks occur is used, the elongation S (%) of the optical functional layer calculated by the following formula (1) satisfies 1.3≦S. S(%)={(R2 / R1)-1}×100 ···(1) (where R2 is the distance from the axial center of the mandrel to the outer surface of the optical laminate, and R1 is the distance from the axial center of the mandrel to an imaginary line indicating a position corresponding to 1 / 2 of the total thickness of the optical laminate.)

[0017]

[10] The optical laminate described in claim 9, wherein when the optical laminate is bent 180 degrees so that the surface on which the antifouling layer is formed is on the inside, and a mandrel of the smallest diameter on which no cracks occur is used, the compression ratio C (%) of the optical functional layer calculated by the following formula (2) satisfies 4.5≦C. C(%)={1-(R3 / R1)}×100...(2) (where R3 is the distance from the axial center of the mandrel to the surface of the optical laminate on the antifouling layer side, and R1 is the distance from the axial center of the mandrel to an imaginary line indicating a position corresponding to 1 / 2 of the total thickness of the optical laminate.)

[0018]

[11] An article comprising the optical laminate according to any one of [1] to

[10] above. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide an optical layered body that can achieve excellent scratch resistance and further improves flex resistance, and an article including the same. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 2 is a cross-sectional view showing another example of the optical laminate of the present embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing another example of the optical laminate of the present embodiment. [Figure 3] FIG. 2 is a schematic diagram illustrating an example of a manufacturing apparatus that can be used in the method for manufacturing an optical laminate of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, this embodiment will be described in detail with reference to the drawings as appropriate. The drawings used in the following description may show characteristic portions enlarged for the sake of convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may differ from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited to them and can be implemented with appropriate changes within the scope of the effects.

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

[0023] FIG. 2 is a cross-sectional view showing another example of the optical laminate of the present embodiment. The optical laminate 101 shown in FIG. 2 is the same as the optical laminate 102 shown in FIG. 1, except that an antireflection layer is provided as the optical functional layer 14. As shown in FIG. 1, the optical functional layer 14 (antireflection layer) is made of a laminate in which low refractive index layers 14b and high refractive index layers 14a are alternately stacked. The optical functional layer 14 shown in FIG. 1 is made of a hard coat layer 12, an adhesive layer 13, a high refractive index layer 14a, a low refractive index layer 14b, a high refractive index layer 14a, a low refractive index layer 14b, and an antifouling layer 15 stacked in this order from the transparent substrate 11 side. 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 may be formed from a transparent material that can transmit light in the visible light range. For example, a plastic film is preferably used as the transparent substrate 11. Specific examples of materials that can be used to form 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] The term "transparent material" as used in the present invention refers to a material having a transmittance of 80% or more for light in the wavelength range used, provided that the effect of the present invention is not impaired. In addition, in this embodiment, "(meth)acrylic" means methacrylic and acrylic.

[0026] The transparent substrate 11 may contain a reinforcing material as long as it does not significantly impair the optical properties. Examples of the reinforcing material include cellulose nanofiber and nanosilica. In particular, polyester-based resins, acetate-based resins, polycarbonate-based resins, and polyolefin-based resins are preferably used as the reinforcing material. Specifically, a triacetyl cellulose (TAC) substrate is preferably used as the reinforcing material. The transparent substrate 11 may also be a glass film, which is an inorganic substrate.

[0027] When the plastic film is a TAC substrate, forming a hard coat layer 12 on one side thereof forms a permeation layer formed by the penetration of some of the components constituting the hard coat layer 12. As a result, the adhesion between the transparent substrate 11 and the hard coat layer 12 is improved, and the occurrence of interference fringes due to the difference in refractive index between the layers can be suppressed.

[0028] The transparent substrate 11 may be a film having optical and / or physical functions. Examples of films having optical and / or physical functions include a polarizing plate, a retardation compensation film, a heat-shielding film, a transparent conductive film, a brightness-enhancing film, and a barrier-enhancing film.

[0029] The thickness of the transparent substrate 11 is not particularly limited, but is preferably, for example, 25 μm or more, and more preferably 40 μm or more. When the thickness of the transparent substrate 11 is 25 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 25 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 there are fewer concerns about production. When the thickness of the transparent substrate 11 is 40 μm or more, wrinkles are even less likely to occur, which is preferable.

[0030] When the production is carried out using a roll, the thickness of the transparent substrate 11 is preferably 1000 μm or less, and more preferably 600 μm or less. When the thickness of the transparent substrate 11 is 1000 μm or less, the optical laminate 10 during production and the optical laminate 10 after production can be easily wound into a roll, and the optical laminate 10 can be produced efficiently. Furthermore, when the thickness of the transparent substrate 11 is 1000 μm or less, the optical laminate 10 can be made thinner and lighter. When the thickness of the transparent substrate 11 is 600 μm or less, the optical laminate 10 can be produced more efficiently and can be made even thinner and lighter, which is preferable.

[0031] The surface of the transparent substrate 11 may be previously subjected to an etching treatment such as sputtering, corona discharge, ultraviolet irradiation, electron beam irradiation, conversion treatment, oxidation, and / or an undercoat treatment. By previously performing these treatments, adhesion to the hard coat layer 12 to be formed on the transparent substrate 11 can be improved. Furthermore, before forming the hard coat layer 12 on the transparent substrate 11, it is also preferable to remove dust and clean the surface of the transparent substrate 11 by subjecting the surface of the transparent substrate 11 to solvent washing, ultrasonic cleaning, or the like, as necessary.

[0032] The hard coat layer 12 contains a binder resin and a filler as essential components, and may optionally contain other components such as a dispersant. Known binder resins can be used. The filler is contained in the binder resin to the extent that transparency is not impaired. The filler may be an organic filler, an inorganic filler, or a combination of an organic filler and an inorganic filler, but from the viewpoint of hardness and flex resistance, an inorganic filler is preferred, silica particles made of silica are more preferred, and surface-modified silica particles are particularly preferred.

[0033] The binder resin used in the hard coat layer 12 is preferably transparent, and examples thereof include ionizing radiation curable resins that are cured by ultraviolet light or electron beams, thermoplastic resins, and thermosetting resins.

[0034] Examples of the ionizing radiation curable resin used as the binder resin of the hard coat layer 12 include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, and N-vinylpyrrolidone. Examples of the compound that is an ionizing radiation curable resin 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 ... Examples of suitable polyfunctional compounds include erythritol penta(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, isocyanuric acid tri(meth)acrylate, isocyanuric acid di(meth)acrylate, polyester tri(meth)acrylate, polyester di(meth)acrylate, bisphenol di(meth)acrylate, diglycerin tetra(meth)acrylate, adamantyl di(meth)acrylate, isobornyl di(meth)acrylate, 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 particularly preferred. The term "(meth)acrylate" refers to methacrylate and acrylate. Furthermore, the above-mentioned compounds modified with PO (propylene oxide), EO (ethylene oxide), CL (caprolactone), etc. can also be used as ionizing radiation curable resins. Furthermore, urethane (meth)acrylate oligomers, epoxy (meth)acrylate oligomers, etc. can also be used from the viewpoint of film formation of the hard coat layer and adjustment of viscoelasticity.

[0035] Examples of thermoplastic resins used as the binder resin of the hard coat layer 12 include styrene-based resins, (meth)acrylic resins, vinyl acetate-based resins, vinyl ether-based resins, halogen-containing resins, alicyclic olefin-based resins, polycarbonate-based resins, polyester-based resins, polyamide-based resins, cellulose derivatives, silicone-based resins, and rubber or elastomers. The thermoplastic resins are preferably amorphous and soluble in organic solvents (particularly common solvents capable of dissolving multiple polymers and curable compounds). In particular, from the viewpoints of transparency and weather resistance, styrene-based resins, (meth)acrylic resins, alicyclic olefin-based resins, polyester-based resins, cellulose derivatives (cellulose esters, etc.), and the like are preferred.

[0036] The hard coat layer 12 contains, for example, a binder resin and silica particles as a filler. The silica particles preferably contain silica particles that have been surface-modified in advance. 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. These may be used alone or in combination. The silane compound is appropriately selected depending on the type of binder resin. When the binder resin contains a functional group, a silane compound having the same functional group as the binder resin is preferred. For example, when the binder resin contains a (meth)acrylate compound as an ionizing radiation-curable resin, the silane compound is preferably a (meth)acryloyl group-containing alkoxysilane compound. Note that "(meth)acrylate" refers to methacrylate and / or acrylate. In the present invention, methacrylate and acrylate are treated as the same entity in terms of reaction mechanism. The silane compound used for surface modification preferably has an alkoxysilyl group or a silanol group at its terminal, since this improves bonding with the hydroxyl groups present on the surface of the silica particles. By pre-surface-modifying the silica particles, the dispersibility in the binder resin is improved, and the reaction between the surface treatment agent used for surface modification and the binder resin causes the particles to bond more firmly to the binder resin, 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 side of the optical functional layer 14. In this case, the hard coat layer 12 and the optical functional layer 14 are more strongly bonded via the adhesive layer 13. Examples of a method for exposing the silica particles include glow treatment, which will be described later, and in this case, the surface modification on the exposed silica surface is removed. The filler is exposed on the surface of the hard coat layer, and the surface modification is removed at that time, which generates an electrostatic attraction between the hydroxyl groups on the filler surface and the adhesion layer 13 described below, further improving adhesion. The exposed filler also acts as an anchor to dig into the adhesion layer 13, which also contributes to improved adhesion. The improvement in flex resistance is achieved by a combination of the bonding with the binder resin due to the surface modification of the silica surface described above and the interaction between the silica and the adhesion layer.

[0037] The average particle size of the filler in the hard coat layer 12 is, for example, 800 nm or less, preferably 780 nm or less, and more preferably 100 nm or less. When the particle size of the filler is within this range, the haze value of the entire optical laminate 10 is 2% or less. An optical laminate 10 with a haze of 2% or less has high transparency and serves as a so-called clear antireflection film.

[0038] The surface of the hard coat layer 12 is preferably subjected to, for example, glow discharge treatment, plasma treatment, ion etching, alkali treatment, etc. 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 / m as electrode power density. 2 ~11000W / m 2 It can be done at 1600W / m 2 ~7000W / m 2 It is preferable to do so. By performing a glow discharge treatment on the surface of the hard coat layer 12, the surface of the hard coat layer 12 is roughened at the nanometer level and weakly bonded substances present on the surface of the hard coat layer 12 are removed. As a result, adhesion between the hard coat layer 12 and the adhesion layer 13 formed on the hard coat layer 12 is improved. This also has the effect of exposing silica particles from the hard coat layer 12. Furthermore, while increasing the strength during the discharge treatment tends to improve the flex resistance described below, this effect plateaus once the discharge strength exceeds a certain level. Furthermore, excessive glow discharge strength can lead to deterioration of the resin that constitutes the hard coat layer. Therefore, it is preferable to perform the glow discharge treatment at a discharge strength within the aforementioned range.

[0039] If an anti-glare optical laminate is desired, the average particle size of the filler in the hard coat layer 12 may be, for example, 0.5 μm or more. Suitable fillers of this size include organic fine particles of acrylic resin, for example. When the particle size of the filler is within this range, the haze value of the entire optical laminate 10 exceeds 2%. An optical laminate 10 with a haze of more than 2% has anti-glare properties and serves as a so-called anti-glare (AG) type anti-reflection film. Even in this case, the average particle size of the filler is preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less. As the filler contained in the hard coat layer 12, various reinforcing materials can be used within a range that does not impair the optical properties in order to impart toughness to the hard coat layer 12. Examples of reinforcing materials include cellulose nanofibers.

[0040] The thickness of the hard coat layer 12 is not particularly limited, but is preferably 0.5 μm or more, and more preferably 1 μm or more. The thickness of the hard coat layer 12 is preferably 100 μm or less. When the thickness of the hard coat layer 12 is 0.5 μm or more, sufficient hardness is obtained, making it less susceptible to scratches during production. Furthermore, when the thickness of the hard coat layer 12 is 100 μm or less, the optical laminate 10 can be made thinner and lighter. Furthermore, when the thickness of the hard coat layer 12 is 100 μm or less, microcracks in the hard coat layer 12 that occur when the optical laminate 10 is bent during production are less likely to occur, improving productivity.

[0041] The hard coat layer 12 may be a single layer or a laminate of multiple layers. The hard coat layer 12 may further be provided with known functions such as ultraviolet absorption, antistatic properties, refractive index adjustment, and hardness adjustment. Furthermore, the function imparted to the hard coat layer 12 may be imparted to a single hard coat layer, or may be imparted to a plurality of separate layers.

[0042] The adhesion layer 13 is a layer formed to improve adhesion between the transparent substrate 11 or 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 FIG. 2, the adhesion layer 13 is provided between the hard coat layer 12 and the optical functional layer 14. The adhesion layer 13 functions to adhere the hard coat layer 12 and the optical functional layer 14. 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 deficient 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 be, for example, SiOx, where x is greater than 0 and less than 2.0. The adhesion layer may also be formed from a mixture of multiple types of metals or metal oxides. The thickness of the adhesive layer is preferably more than 0 nm and not more than 20 nm, particularly preferably 1 nm or more and 10 nm or less, from the viewpoint of maintaining transparency and adhesiveness with the optical functional layer and obtaining good optical properties.

[0043] The optical function layer 14 is a laminate that exhibits an anti-reflection function. The optical function layer 14 shown in Fig. 2 is a laminate of four layers in total, in which high-refractive-index layers 14a and low-refractive-index layers 14b are alternately stacked in this order from the adhesive layer 13 side. The number of high-refractive-index layers 14a and low-refractive-index layers 14b is not particularly limited, and the number of high-refractive-index layers 14a and low-refractive-index layers 14b can be any number.

[0044] 2, the optical functional layer 14 is made of a laminate in which low refractive index layers 14b and high refractive index layers 14a are alternately stacked, and therefore, light incident from the antifouling layer 15 side interferes with the optical functional layer 14, thereby reducing the intensity of the reflected light and providing an antireflection function. Therefore, an antireflection function is obtained that prevents light incident from the antifouling layer 15 side from being reflected in one direction.

[0045] The low refractive index layer 14b contains, for example, a metal oxide. The low refractive index layer 14b may contain an oxide of Si from the viewpoints of availability and cost, and is preferably a layer whose main component is SiO2 (oxide of Si) or the like. A single SiO2 layer is colorless and transparent. In this embodiment, the main component of the low refractive index layer 14b means a component contained in the low refractive index layer 14b at 50 mass % or more. When the low refractive index layer 14b is a layer mainly composed of an oxide of Si, it may contain less than 50 mass% of another element. The content of elements other than the oxide of Si is preferably 10% or less. Examples of other elements that may be included include Na for improving durability, Zr, Al, or N for improving hardness, and Zr and Al for improving alkali resistance.

[0046] The refractive index of the low refractive index layer 14b is preferably 1.20 to 1.60, and more preferably 1.30 to 1.50. Examples of the dielectric material used for the low refractive index layer 14b include magnesium fluoride (MgF2, refractive index 1.38).

[0047] The refractive index of the high refractive index layer 14a is preferably 2.00 to 2.60, and more preferably 2.10 to 2.45. Examples of dielectric materials that can be used for the high refractive index layer 14a include niobium pentoxide (Nb2O5, refractive index 2.33), titanium oxide (TiO2, refractive index 2.33 to 2.55), tungsten oxide (WO3, refractive index 2.2), cerium oxide (CeO2, refractive index 2.2), tantalum pentoxide (Ta2O5, refractive index 2.16), zinc oxide (ZnO, refractive index 2.1), indium tin oxide (ITO, refractive index 2.06), and zirconium oxide (ZrO2, refractive index 2.2). 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.

[0048] The optical function layer 14 preferably uses, for example, niobium pentoxide (Nb2O5, refractive index 2.33) as the high refractive index layer 14a and SiO2 as the low refractive index layer 14b.

[0049] The film thickness of the low refractive index layer 14b may be in the range of 1 nm to 200 nm, and is appropriately selected depending on the wavelength range in which the anti-reflection function is required. The thickness of the high refractive index layer 14a may be, for example, 1 nm or more and 200 nm or less, and is appropriately selected depending on the wavelength range in which the anti-reflection function is required. The thicknesses of the high refractive index layer 14a and the low refractive index layer 14b can be appropriately selected depending on the design of the optical function layer 14. For example, from the adhesive layer 13 side, the layers may be a high refractive index layer 14a of 5 to 50 nm, a low refractive index layer 14b of 10 to 80 nm, a high refractive index layer 14a of 20 to 200 nm, and a low refractive index layer 14b of 50 to 200 nm.

[0050] Of the layers forming the optical functional layer 14, a low refractive index layer 14b is disposed on the side of the antifouling layer 15. It is preferable that the low refractive index layer 14b of the optical functional layer 14 is in contact with the antifouling layer 15, as this improves the antireflection performance of the optical functional layer 14.

[0051] The antifouling layer 15 is formed on the outermost surface of the optical functional layer 14 and prevents the optical functional layer 14 from being soiled. Furthermore, when the antifouling layer 15 is applied to a touch panel or the like, it suppresses wear of the optical functional layer 14 due to its abrasion resistance. The antifouling layer 15 of this embodiment is made of a vapor-deposited film formed by vapor-depositing an antifouling material. In this embodiment, the antifouling layer 15 is formed by vacuum-depositing a fluorine-based organic compound as the antifouling material on one surface of the low refractive index layer 14b that constitutes the optical function layer 14. In this embodiment, the antifouling material contains a fluorine-based organic compound, which results in an optical laminate 10 with even better abrasion resistance and alkali resistance.

[0052] A compound comprising a fluorine-modified organic group and a reactive silyl group (e.g., alkoxysilane) is preferably used as the fluorine-based organic compound constituting the antifouling layer 15. Examples of commercially available products include Optool DSX (manufactured by Daikin Corporation) and KY-100 series (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0053] When a compound consisting of a fluorine-modified organic group and a reactive silyl group (e.g., alkoxysilane) is used as the fluorine-based organic compound constituting the antifouling layer 15 and a layer consisting of SiO2 is used as the low refractive index layer 14b of the optical function layer 14 in contact with the antifouling layer 15, a siloxane bond is formed between the silanol group, which is the skeleton of the fluorine-based organic compound, and the SiO2. This results in good adhesion between the optical function layer 14 and the antifouling layer 15, which is preferable.

[0054] The optical thickness of the antifouling layer 15 may be in the range of 1 nm or more and 20 nm or less, and preferably in the range of 3 nm or more and 10 nm or less. If the thickness of the antifouling layer 15 is 1 nm or more, sufficient abrasion resistance can be ensured when the optical laminate 10 is used for touch panels, etc. If the thickness of the antifouling layer 15 is 3 nm or more, the liquid resistance, etc. of the optical laminate 10 is improved. If the thickness of the antifouling layer 15 is 20 nm or less, the time required for vapor deposition can be shortened, allowing for efficient production.

[0055] In the optical laminate 10, 102 configured as described above, the ratio ((A) / (B)) of the Martens hardness (A) measured from the antifouling layer 15 side of the optical laminate 10, 102 to the Martens hardness measured from the hard coat layer 12 side of a laminate having only the transparent substrate 11 and the hard coat layer 12 is 3.6 or less (condition 1). Furthermore, the ratio ((A) / (B)) is preferably 3.5 or less, and more preferably 3.4 or less. When the ratio ((A) / (B)) is 3.6 or less, the difference in hardness between the hard coat layer surface and the antifouling layer surface is small, thereby suppressing deformation, and as a result, excellent scratch resistance can be achieved and bending resistance can be further improved.

[0056] Furthermore, in the optical laminate 10, 102 configured as described above, a difference in contact angle with water before and after 200 horizontal reciprocating movements of the steel wool is measured using a friction tester using steel wool conforming to JIS L0849, and the difference is 20° or less (condition 2). If the optical laminate 10, 102 has high hardness, the difference in contact angle becomes 20° or less, and excellent scratch resistance can be achieved.

[0057] In the optical laminate 10, 102 configured as described above, when the optical laminate 10, 102 is bent 180° so that the surface on which the antifouling layer 15 is formed faces outward, the elongation S (%) of the optical functional layer 14 calculated by the following formula (1) when using a mandrel of the smallest diameter that does not cause cracks preferably satisfies 1.3≦S. This allows the bending resistance of the optical laminate 10, 102 to be further improved. S = {(R2 / R1)-1} × 100 (1) (where R2 is the distance from the axial center of the mandrel to the outer surface of the optical laminate, and R1 is the distance from the axial center of the mandrel to an imaginary line indicating a position corresponding to 1 / 2 of the total thickness of the optical laminate.)

[0058] Furthermore, in the optical laminate 10, 102, when the optical laminate 10, 102 is bent 180° so that the surface on which the antifouling layer 15 is formed faces inward, and a mandrel of the smallest diameter that does not cause cracks is used, the compression ratio C (%) of the optical functional layer 14 calculated by the following formula (2) preferably satisfies 4.5≦C, and more preferably satisfies 5≦C. This allows the bending resistance of the optical laminate 10, 102 to be further improved. C(%)={1-(R3 / R1)}×100 ···(2) (where R3 is the distance from the axial center of the mandrel to the surface of the optical laminate on the antifouling layer side, and R1 is the distance from the axial center of the mandrel to an imaginary line indicating a position corresponding to 1 / 2 of the total thickness of the optical laminate.)

[0059] Furthermore, it is preferable that the optical functional layer 14 satisfy both the above-mentioned ranges for the elongation percentage S (%) and the above-mentioned ranges for the compression percentage C (%). That is, in the optical laminate 10, 102, when the optical laminate 10, 102 is bent 180° so that the surface on which the antifouling layer 15 is formed is on the outside, the elongation percentage S (%) of the optical functional layer 14 calculated by the following formula (1) satisfies 1.3≦S when a mandrel of the smallest diameter at which no cracks occur is used, and when the optical laminate 10, 102 is bent 180° so that the surface on which the antifouling layer 15 is formed is on the inside, the compression percentage C (%) of the optical functional layer 14 calculated by the above formula (2) satisfies 4.5≦C. This can further improve the bending resistance of the optical laminate 10, 102.

[0060] The above elongation percentages are values ​​when the substrate is PET and the thickness is 50 μm, and these values ​​may vary if the thickness is reduced.

[0061] In the optical laminate 10, 102 configured as described above, when the thickness of the hard coat layer of the optical laminate is 5 μm, if the optical laminate 10, 102 is bent 180° so that the surface on which the anti-fouling layer 15 is formed is facing outward, the diameter of the mandrel is gradually changed to one that is smaller, and the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel at which the first crack was discovered is preferably 4.0φmm or less, more preferably 3.5φmm or less, and even more preferably 3.0φmm or less.

[0062] Furthermore, when the thickness of the hard coat layer of the optical laminate is 5 μm, if the optical laminate 10, 102 is bent 180° so that the surface on which the anti-fouling layer 15 is formed is on the inside, the diameter of the mandrel is gradually changed to one that is smaller, and the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel at which the first crack was discovered is preferably 1.1φmm or less, and more preferably less than 1.0φmm.

[0063] Furthermore, when the thickness of the hard coat layer of the optical laminate is 5 μm, when the optical laminate 10, 102 is bent 180° so that the side on which the anti-fouling layer 15 is formed is on the outside, it is more preferable that the diameter of the mandrel is gradually reduced to 4.0φmm or less, and when the optical laminate 10, 102 is bent 180° so that the side on which the anti-fouling layer 15 is formed is on the inside, it is more preferable that the diameter of the mandrel is gradually reduced to 0.2 mm larger than the diameter of the mandrel on which the first crack is found is 1.1φmm or less.

[0064] In the optical laminate 10, 102 configured as described above, when the thickness of the hard coat layer of the optical laminate is 10 μm, if the optical laminate 10, 102 is bent 180° so that the surface on which the anti-fouling layer 15 is formed is facing outward, the diameter of the mandrel is gradually changed to one that is smaller, and the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel at which the first crack was discovered is preferably 4.0φmm or less, more preferably 3.5φmm or less, and even more preferably 3.0φmm or less.

[0065] Furthermore, when the thickness of the hard coat layer of the optical laminate is 10 μm, if the optical laminate 10, 102 is bent 180° so that the surface on which the antifouling layer 15 is formed is on the inside, the diameter of the mandrel is gradually changed to one that is smaller, and the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel at which the first crack was discovered is preferably 1.4φmm or less, and more preferably 1.2φmm or less.

[0066] Furthermore, when the thickness of the hard coat layer of the optical laminate is 10 μm, when the optical laminate 10, 102 is bent 180° so that the side on which the anti-fouling layer 15 is formed is on the outside, it is more preferable that the diameter of the mandrel is gradually reduced to 4.0φmm or less, and when the optical laminate 10, 102 is bent 180° so that the side on which the anti-fouling layer 15 is formed is on the inside, it is more preferable that the diameter of the mandrel is gradually reduced to 0.2 mm larger than the diameter of the mandrel on which the first crack is found is 1.4φmm or less.

[0067] In the optical laminate 10, 102 configured as described above, when the thickness of the hard coat layer of the optical laminate is 2 μm, if the optical laminate 10, 102 is bent 180° so that the surface on which the anti-fouling layer 15 is formed is facing outward, the diameter of the mandrel is gradually changed to one that is smaller, and the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel at which the first crack was discovered is preferably 4.0φmm or less, more preferably 3.5φmm or less, and even more preferably 3.0φmm or less.

[0068] Furthermore, when the thickness of the hard coat layer of the optical laminate is 2 μm, if the optical laminate 10, 102 is bent 180° so that the surface on which the antifouling layer 15 is formed is on the inside, the diameter of the mandrel is gradually changed to one that is smaller, and the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel at which the first crack was discovered is preferably 1.1φmm or less, and more preferably less than 1.0φmm.

[0069] Furthermore, when the thickness of the hard coat layer of the optical laminate is 2 μm, when the optical laminate 10, 102 is bent 180° so that the side on which the anti-fouling layer 15 is formed is on the outside, it is more preferable that the diameter of the mandrel is gradually reduced to 4.0φmm or less, and when the optical laminate 10, 102 is bent 180° so that the side on which the anti-fouling layer 15 is formed is on the inside, it is more preferable that the diameter of the mandrel is gradually reduced to 0.2 mm larger than the diameter of the mandrel on which the first crack is found is 1.1φmm or less.

[0070] The mandrel diameter is calculated by cutting out three identical samples, measuring them, and averaging the three measurements.

[0071] [Method of manufacturing optical laminate] The optical laminate 10 of this embodiment shown in FIG. 2 can be produced, for example, by the method described below. In this embodiment, as an example of a method for producing the optical laminate 10, a case in which the optical laminate 10 is produced 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 for forming the hard coat layer 12 is applied onto the transparent substrate 11 by a known method, and cured by a known method corresponding to the material for forming the hard coat layer 12. The slurry used may be, for example, a composition containing a binder resin and silica particles as a filler. This composition is applied to the transparent substrate 11 and then cured. In this way, the hard coat layer 12 is formed on the transparent substrate 11 (hard coat layer forming step). The composition may contain one or more additives such as a polymerization initiator and a leveling agent, as necessary. As the polymerization initiator, for example, a photopolymerization initiator is used. Thereafter, the transparent substrate 11 having the hard coat layer 12 formed on its surface is wound into a roll 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 function layer forming step is performed to form an optical function layer 14. Thereafter, an antifouling layer forming step is performed to form an antifouling layer 15 on the optical function 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 the optical function layer forming step, and then perform the adhesion layer forming step and the optical function layer forming step. Also, in this embodiment, it is preferable to perform a second surface treatment step to treat the surface of the optical function layer 14 after the optical function layer forming step, and then perform the antifouling layer forming step.

[0073] In the method for producing the optical laminate 10 of this embodiment, 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 preferably performed consecutively while the optical laminate in the middle of production is maintained 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 performed consecutively while the optical laminate in the middle of production is maintained under reduced pressure, for example, a sputtering device equipped with the thin film formation device described in Patent Document 4 can be used.

[0074] A specific example of a manufacturing apparatus that can be used in the method for manufacturing an optical laminate of this embodiment is a manufacturing apparatus 20 shown in FIG. The manufacturing apparatus 20 shown in Figure 3 includes a roll unwinding device 4, a preprocessing device 2A, a sputtering device 1, a preprocessing 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 unwinds a substrate from a roll, passes the substrate through connected devices in succession (preprocessing device 2A, sputtering device 1, preprocessing device 2B, and vapor deposition device 3 in Figure 3), and then winds it up, thereby continuously forming multiple layers on the substrate.

[0075] When the optical laminate 10 is produced using a roll-to-roll production device, the conveying speed (line speed) of the optical laminate 10 during production can be appropriately set. The conveying speed is, for example, 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 Fig. 3 has a chamber 34 the inside of which is kept at a predetermined reduced pressure, one or more vacuum pumps 21 (one in Fig. 3) that exhaust gas from the chamber 34 to create a reduced pressure atmosphere, and an unwinding roll 23 and a guide roll 22 installed in the chamber 34. As shown in Fig. 3, the chamber 34 is connected to the chamber 31 of the sputtering device 1 via the pretreatment device 2A. The transparent substrate 11 having the hard coat layer 12 formed on the surface thereof is wound around the unwinding roll 23. The unwinding roll 23 supplies the transparent substrate 11 having the hard coat layer 12 formed on the surface thereof to the pretreatment device 2A at a predetermined transport speed.

[0077] <Pre-treatment device 2A> Pretreatment device 2A shown in Fig. 3 has chamber 32, the interior of which is kept at a predetermined reduced pressure, can roll 26, multiple (two in Fig. 3) guide rolls 22, and plasma discharge device 42. As shown in Fig. 3, can roll 26, guide roll 22, and plasma discharge device 42 are installed in chamber 32. As shown in Fig. 3, chamber 32 is connected to chamber 31 of sputtering device 1.

[0078] The can roll 26 and the guide roll 22 transport the transparent substrate 11 on which the hard coat layer 12 has been formed, which has been sent from the roll unwinding device 4, at a predetermined transport speed, and send the transparent substrate 11 with the surface of the hard coat layer 12 treated to the sputtering device 1. As shown in Fig. 3, the plasma discharge device 42 is disposed opposite the outer peripheral surface of the can roll 26 at a predetermined distance. The plasma discharge device 42 ionizes gas by glow discharge. The gas is preferably inexpensive, inert, and does not affect optical properties, and examples of the gas that can be used include argon gas, oxygen gas, nitrogen gas, and helium gas. In this embodiment, argon gas or oxygen gas is preferably used as the gas.

[0079] <Sputtering equipment> The sputtering apparatus 1 shown in Fig. 3 includes a chamber 31, the interior of which is maintained at a predetermined reduced pressure, one or more vacuum pumps 21 (two in Fig. 3) that exhaust gas from the chamber 31 to create a reduced pressure atmosphere, a film-forming roll 25, a plurality of guide rolls 22 (two in Fig. 4), and a plurality of film-forming units 41 (four in the example shown in Fig. 3). As shown in Fig. 3, the film-forming roll 25, the guide roll 22, and the film-forming units 41 are installed in the chamber 31. As shown in Fig. 3, the chamber 31 is connected to a chamber 32 of a pretreatment device 2B.

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

[0081] As shown in FIG. 3 , multiple film forming units 41 are disposed facing the outer circumferential surface of the film forming roll 25 at a predetermined distance, surrounding the film forming roll 25. The number of film forming units 41 is determined based on the total number of layers including the adhesive layer 13 and the high-refractive index layers 14a and low-refractive index layers 14b that form the optical functional layer 14. When the total number of layers including the adhesive layer 13 and the high-refractive index layers 14a and low-refractive index layers 14b that form the optical functional layer 14 is large, making it difficult to ensure sufficient distance between adjacent film forming units 41, multiple film forming rolls 25 may be provided within the chamber 31, and film forming units 41 may be disposed around each film forming roll 25. When multiple film forming rolls 25 are provided, additional guide rolls 22 may be installed as necessary. Multiple chambers 31 each equipped with a film forming roll 25 and a film forming unit 41 may be connected together. Furthermore, the diameter of the film forming roll 25 may be appropriately adjusted to facilitate ensuring sufficient distance between adjacent film forming units 41.

[0082] A predetermined target (not shown) is installed in each film forming unit 41. A voltage is applied to the target using a known structure. In this embodiment, a gas supply unit (not shown) that supplies a predetermined reactive gas and carrier gas to the target at a predetermined flow rate, and a known magnetic field generating source (not shown) that forms a magnetic field on the surface of the target are installed near the target.

[0083] The target material and the type and flow rate of the reactive gas are determined appropriately depending on 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-forming unit 41 and the film-forming roll 25. For example, when forming a layer made of SiO2, Si is used as the target and O2 is used as the reactive gas. For example, when forming a layer made of Nb2O5, Nb is used as the target and O2 is used as the reactive gas. The low-refractive index layer 14b is preferably formed at a vacuum level of less than 0.5 Pa, and the high-refractive index layer 14a is preferably formed at a vacuum level of less than 1.0 Pa. Forming these layers at these vacuum levels results in a denser optical function layer 14, a lower water vapor permeability, and improved durability.

[0084] In this embodiment, it is preferable to use magnetron sputtering as the sputtering method from the viewpoint of increasing the film formation speed. The sputtering method is not limited to magnetron sputtering, and may be a two-pole sputtering method that uses plasma generated by DC glow discharge or high frequency, or a three-pole sputtering method that adds a hot cathode.

[0085] The sputtering apparatus 1 is equipped with an optical monitor (not shown) as a measurement unit that measures optical properties after forming each layer that will become the adhesion layer 13 and the optical functional layer 14. This makes it possible to confirm the quality of the formed adhesion layer 13 and optical functional layer 14. When 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 uses an optical head capable of scanning in the width direction to measure 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. When such an optical monitor is provided, for example, the peak wavelength of reflectance is measured as the optical property, and converted into optical thickness, thereby making it possible to measure the optical thickness distribution in the width direction of the adhesion layer 13 and the optical functional layer 14. By measuring the optical properties using the optical monitor, it is possible to form an optical laminate 10 that includes an adhesion layer 13 and an optical functional layer 14 with optimal optical properties while adjusting the sputtering conditions in real time.

[0087] <Pre-treatment device 2B> Pretreatment device 2B shown in Fig. 3 has chamber 32, the interior of which is kept at a predetermined reduced pressure, can roll 26, multiple (two in Fig. 3) guide rolls 22, and plasma discharge device 42. As shown in Fig. 3, can roll 26, guide roll 22, and plasma discharge device 42 are installed in chamber 32. As shown in Fig. 3, chamber 32 is connected to chamber 33 of vapor deposition device 3.

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

[0089] <Vapor deposition equipment> The vapor deposition apparatus 3 shown in Figure 4 includes a chamber 33 the interior of which is maintained at a predetermined reduced pressure, one or more vacuum pumps 21 (one in Figure 3) that evacuate gas from the chamber 33 to create a reduced pressure atmosphere, multiple guide rolls 22 (four in Figure 3), a vapor deposition source 43, and a heating device 53. As shown in Figure 3, the guide rolls 22 and the vapor deposition source 43 are installed in the chamber 33. The chamber 33 is connected to a chamber 35 of the roll winding device 5.

[0090] The vapor deposition source 43 is disposed opposite the transparent substrate 11, on which the surface of the optical functional layer 14 has been treated, and which is being transported substantially horizontally between two adjacent guide rolls 22. The vapor deposition source 43 supplies evaporated gas made of a 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 as desired. The heating device 53 heats the material that will become the antifouling layer 15 to the vapor pressure temperature. The heating device 53 can be one that uses a resistance heating method, a heater heating method, an induction heating method, an electron beam heating method, or the like. In the resistance heating method, a container that contains the antifouling material that will become the antifouling layer 15 is heated by passing electricity through it as a resistor. In the heater heating method, the container is heated by a heater arranged around the periphery of the container. In the induction heating method, the container or the antifouling material is heated by electromagnetic induction from an externally installed induction coil.

[0091] The vapor deposition device 3 shown in Figure 3 is equipped with a guide plate (not shown) that guides the vapor deposition material evaporated from the vapor deposition source 43 to a predetermined position, a film thickness meter (not shown) that observes the thickness of the antifouling layer 15 formed by vapor deposition, a vacuum pressure meter (not shown) that measures the pressure inside the chamber 33, and a power supply unit (not shown). The guide plate may have any shape as long as it can guide the evaporated deposition material to a desired position. If the guide plate is not necessary, it does not have to be provided. As the vacuum pressure gauge, for example, an ion gauge can be used. The power supply device may be, for example, a high frequency power supply.

[0092] <Roll winding device> The roll winding device 5 shown in Figure 3 has a chamber 35 inside which a predetermined reduced pressure atmosphere is maintained, one or more vacuum pumps 21 (one in Figure 3) that exhaust 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. The transparent substrate 11 (optical laminate 10) having each layer formed on its surface up to the antifouling layer 15 is wound around the winding roll 24. The winding roll 24 and the guide roll 22 wind up the optical laminate 10 at a predetermined winding speed. If necessary, a carrier film may also be used.

[0093] 4 may be equipped with a dry pump, an oil rotary pump, a turbomolecular pump, an oil diffusion pump, a cryopump, a sputter ion pump, a getter pump, etc. The vacuum pump 21 may be appropriately selected or used in combination to create a desired reduced pressure state in each of the chambers 31, 32, 33, 34, and 35.

[0094] The location and number of vacuum pumps 21 installed in manufacturing apparatus 20 are not particularly limited as long as they can maintain both chamber 31 of sputtering apparatus 1 and chamber 33 of vapor deposition apparatus 3 at the desired reduced pressure. In manufacturing apparatus 20 shown in FIG. 3, roll unwinding apparatus 4, preprocessing apparatus 2A, sputtering apparatus 1, preprocessing apparatus 2B, vapor deposition apparatus 3, and roll winding apparatus 5 are connected. Therefore, vacuum pumps 21 may be installed in each of chambers 31, 32, 33, 34, and 35, or may be installed in only some of chambers 31, 32, 33, 34, and 35, as long as they can maintain both chamber 31 of sputtering apparatus 1 and chamber 33 of vapor deposition apparatus 3 at the desired reduced pressure.

[0095] Next, we will explain a method of using the manufacturing apparatus 20 shown in Figure 3 to continuously perform the first surface treatment process, adhesion layer formation process, optical functional layer formation process, second surface treatment process, and antifouling layer formation process while maintaining the optical laminate 10 in the middle of production under reduced pressure. First, the unwinding roll 23 around which the transparent substrate 11 having the 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 send the transparent substrate 11 having the hard coat layer 12 formed on its surface to the pretreatment device 2A at a predetermined transport speed.

[0096] Next, in the chamber 32 of the pretreatment device 2A, a first surface treatment step is performed as a pretreatment for the surface on which the adhesion layer 13 and the optical functional layer 14 are to 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 treating the surface of the hard coat layer 12 running on the can roll 26.

[0097] For example, glow discharge treatment, plasma treatment, ion etching, alkali treatment, etc. can be used as a surface treatment method for the hard coat layer 12. As described above, among these, glow discharge treatment is preferred because it allows treatment over a large area.

[0098] Next, an adhesion layer forming step and an optical function layer forming step are performed in the chamber 31 of the sputtering apparatus 1. Specifically, the film forming 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 function layer 14 are formed on the hard coat layer 12 running on the film forming roll 25.

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

[0100] When an SiOx film is formed as the adhesion layer 13, it is preferable to form it by reactive sputtering using a silicon target in a mixed gas atmosphere of oxygen gas and argon gas. When the adhesion layer 13, the high refractive index layer 14a, and the low refractive index layer 14b are successively laminated by sputtering, different target materials may be used for forming 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 layers made of the target material and layers made of an oxide of the target material may be alternately formed by changing the flow rate of oxygen (reactive gas) during sputtering, to form the adhesion layer 13, the high refractive index layer 14a, and the low refractive index layer 14b.

[0101] The pressure during sputtering to form the adhesion layer 13 and the optical function 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 the pressure during sputtering is reduced to 1 Pa or less, the mean free path of the film-forming molecules becomes longer, and the film-forming molecules are deposited while maintaining high energy, resulting in a denser and better film quality. It is preferable that the pressure during sputtering of the high refractive index layer and the low refractive index layer be different. This is because the mean free path differs depending on the film-forming species. By changing the pressure for each film-forming species, a denser film can be formed.

[0102] Thereafter, the transparent substrate 11 having the adhesive layer 13 and the optical functional layer 14 formed on the hard coat layer 12 is sent to the pretreatment device 2B by the rotation of the film-forming roll 25 and the guide roll 22. Next, in the chamber 32 of the pretreatment device 2B, a second surface treatment step is carried out as a pretreatment for the surface on which the antifouling layer 15 is to be formed. In this embodiment, the second surface treatment step is carried out continuously while maintaining the transparent substrate 11 on which the optical functional layer 14 formed in the optical functional layer forming step under reduced pressure without exposing it to the air. In the second surface treatment process, 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, while a discharge treatment is performed on the surface of the optical functional layer 14 running on the can roll 26.

[0103] For example, glow discharge treatment, plasma treatment, ion etching, alkali treatment, etc. can be used as a surface treatment method for the optical functional layer 14. Among these, glow discharge treatment is preferred because it allows treatment over a large area.

[0104] When the surface of the optical functional layer 14 is subjected to a discharge treatment, the surface of the optical functional layer 14 is etched, and the surface condition of the optical functional layer 14 changes. The surface condition 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 anti-reflection film in which the haze of the optical functional layer 14 is 2.0 or less, the surface condition of the optical functional layer 14 is easily defined by the surface roughness Ra. In addition, for example, in the case of an AG anti-reflection film in which the haze of the optical functional layer 14 is greater than 2.0, the surface condition 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 (ISO4287).

[0105] Thereafter, the transparent substrate 11 with the surface of the optical functional layer 14 treated is sent to the vapor deposition device 3 by the rotation of the can roll 26 and the guide roll 22 . Next, an antifouling layer forming step is carried out in the chamber 33 of the vapor deposition device 3. In this embodiment, the transparent substrate 11, whose surface has been treated with the optical functional layer 14 obtained in the second surface treatment step, is continuously subjected to the antifouling layer forming step while being maintained under reduced pressure without being exposed to the atmosphere. In the antifouling layer forming step, the guide roll 22 is rotated to transport the transparent substrate 11, whose surface has been treated with the optical functional layer 14, at a predetermined transport speed, while vapor deposition source 43 is vapor-deposited onto 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 a vapor pressure temperature by a heating device 53, and the resulting evaporated gas is supplied from a vapor deposition source 43 in a reduced pressure environment and attached to the optical function layer 14 whose surface has been treated, thereby forming the antifouling layer 15 by vacuum deposition. The pressure during vacuum deposition of the antifouling layer 15 is, for example, 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, resulting in a denser and better antifouling layer 15.

[0107] By the above method, an optical laminate 10 is obtained in which the antifouling layer 15 is formed by vacuum deposition on the adhesion layer 13 and the optical functional layer 14 formed by sputtering. The antifouling layer 15 after film formation preferably has an initial fluorine content of 0.03 or more as measured by X-ray fluorescence analysis (XRF).

[0108] Thereafter, the transparent substrate 11 (optical laminate 10) on which each layer up to the antifouling layer 15 has been formed is sent to the roll winding device 5 by the rotation of the guide roll 22. Then, in the chamber 35 of the roll winding device 5, the optical laminate 10 is wound around 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 forming process and the antifouling layer forming process continuously under reduced pressure. In particular, when the optical laminate 10 is continuously produced as a wound body using a roll-to-roll method, as in the manufacturing method of this embodiment using the manufacturing apparatus 20 shown in FIG. 3 , it is more preferable to perform the optical functional layer forming process and the antifouling layer forming process continuously in-line while maintaining a reduced pressure. "In-line" means that the antifouling layer forming process is performed without exposing the optical functional layer 14 formed in the optical functional layer forming process to the atmosphere. By performing the optical functional layer forming process and the antifouling layer forming process continuously under reduced pressure, the formation of a natural oxide film on the optical functional layer 14 formed in the optical functional layer forming process before the antifouling layer 15 is formed can be suppressed. Furthermore, contamination such as foreign matter that adheres to the optical functional layer 14 during winding of the roll can be prevented, which would inhibit the adhesion between the optical functional layer 14 and the antifouling layer 15. Therefore, compared to when, after the optical functional layer forming process, the transparent substrate 11 on which each layer up to the optical functional layer 14 has been formed is removed from the chamber under reduced pressure, and then placed back into the chamber to perform the anti-fouling layer forming process under reduced pressure, an optical laminate with good adhesion between the optical functional layer 14 and the anti-fouling layer 15 and excellent transparency can be obtained.

[0110] Furthermore, since the antifouling layer 15 of the optical laminate 10 of this embodiment is a vapor-deposited film, it has higher abrasion resistance than, for example, an antifouling film formed by a coating method. This is presumably due to the following reasons. Specifically, an antifouling film formed by a coating method has voids caused by the solvent contained in the paint. In contrast, a vapor-deposited film does not have voids caused by the solvent. For this reason, it is presumed that a vapor-deposited film has a higher density and has higher abrasion resistance and alkali resistance than an antifouling film formed by a coating method.

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

[0112] In this embodiment, when the first surface treatment process, the optical functional layer formation process, the second surface treatment process, and the antifouling layer formation process are performed successively while maintaining the optical laminate in the middle of production under reduced pressure, the reduced pressure conditions in the chambers of, for example, the sputtering apparatus and the vapor deposition apparatus may be different, as long as they do not interfere with each production process.

[0113] In this embodiment, it is preferable to measure the film formation results over time using a measuring device in one or more of the adhesion layer formation process, optical function layer formation process, and antifouling layer formation process, and feed the results back to the conditions of the subsequent manufacturing process. This makes it easier to optimize the properties of the entire optical laminate and make the in-plane properties of the optical laminate uniform. In addition, the measuring device can also be used to feedback the manufacturing conditions in the same process. In this case, the layer formed in that process will have uniform and stable properties.

[0114] In this embodiment, the second surface treatment step is performed between the optical functional layer forming step and the antifouling layer forming step, but the second surface treatment step may be performed as needed or may not be performed. Even when the second surface treatment step is not performed, it is preferable to perform the optical functional layer forming step and the antifouling layer forming step consecutively under reduced pressure.

[0115] In the manufacturing method of this embodiment, the optical functional layer is formed under conditions of a predetermined vacuum level or less. This results in a dense optical functional layer 14, a reduced water vapor permeability, and improved abrasion resistance and alkali resistance. Furthermore, by ensuring that the antifouling layer has a thickness equal to or greater than the predetermined thickness, sufficient abrasion resistance and alkali resistance can be ensured.

[0116] In this embodiment, an example has been described in which the optical laminate 10 is continuously manufactured using a roll-to-roll method using a manufacturing apparatus 20 shown in Figure 3, which is equipped with a pre-processing apparatus 2A, a sputtering apparatus 1, a pre-processing apparatus 2B, a vapor deposition apparatus 3, a roll unwinding apparatus 4, and a roll winding apparatus 5. 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 pretreatment devices 2A and 2B, and that includes roll unwinding device 4, sputtering device 1, vapor deposition device 3, and roll winding device 5 connected in this order.

[0117] The manufacturing apparatus 20 shown in FIG. 3 may be provided with a pretreatment chamber (not shown) between the chamber 33 of the vapor deposition apparatus 3 and the chamber 32 of the pretreatment apparatus 2B for cleaning the surface of the optical functional layer 14 on which the antifouling layer 15 is to be formed. The manufacturing apparatus 20 shown in FIG. 3 may be provided with a post-treatment chamber (not shown) between the chamber 33 of the vapor 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 has been formed.

[0118] 3 may be provided with a hard coat layer forming device between the roll unwinding device 4 and the sputtering device 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 continuously produced by the roll-to-roll method, which is preferable.

[0119] In this embodiment, an example has been described in which the optical functional layer formation process is performed using a sputtering device and the antifouling layer formation process is performed using a vapor deposition device, but 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 device (within one chamber).

[0120] In the optical laminate 10 of this embodiment, various layers may be provided as needed on the surface of the transparent substrate opposite the surface on which the optical functional layer or the like is formed. For example, a pressure-sensitive adhesive layer used for bonding to other members may be provided. Furthermore, another optical film may be provided via this pressure-sensitive adhesive layer. Examples of other optical films include films that function as polarizing films, retardation compensation films, half-wave plates, and quarter-wave plates.

[0121] Furthermore, a layer having functions such as antireflection, selective reflection, antiglare, polarization, phase difference compensation, viewing angle compensation or expansion, light guiding, diffusion, brightness improvement, hue adjustment, and conductivity may be formed directly on the opposing surface of the transparent substrate. The optical laminate may have a smooth shape or a shape having a nano-order uneven structure that exhibits a moth-eye or anti-glare function. It may also have a geometric shape on the order of micro to millimeters, such as a lens or prism. The shape can be formed by, for example, a combination of photolithography and etching, shape transfer, heat pressing, or the like. In this embodiment, since the film is formed by vapor deposition or the like, even if the substrate has an uneven shape, the uneven shape can be maintained.

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

[0123] Furthermore, the article is not limited to image display devices, and may be anything to which the optical laminate 10 can be applied, such as window glass or goggles having the optical laminate of this embodiment provided on the surface, the light receiving surface of a solar cell, a smartphone screen or a display such as a notebook PC, an information input terminal, a tablet terminal, an AR (augmented reality) device, a VR (virtual reality) device, an electronic display board, the surface of a glass table, an amusement machine, an operation support device for an aircraft or train, a navigation system, an instrument panel, or the surface of an optical sensor.

[0124] Although the embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be embodied 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 modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. For example, instead of the hard coat layer 12, an anti-glare layer may be formed, or an arbitrary functional layer such as a soft coat layer having flexibility may be added as needed. These may also be laminated. [Example]

[0125] Examples of the present invention will be described below. Note that the optical laminates produced in the following examples and comparative examples are examples that function as anti-reflection films, and the scope of the present invention is not limited to these.

[0126] <Preparation of hard coat layer composition> First, a photocurable composition 1 was prepared, containing 28 mass% of silica particles (filler) with an average particle size of 50 nm relative to the total solid content of the composition. As shown in Table 1, composition 1 was prepared by dissolving acrylate (binder resin), silica particles, and a photopolymerization initiator in a solvent, and then adding a leveling agent.

[0127] [Table 1]

[0128] CN968: Hexafunctional aliphatic urethane acrylate having a polyester backbone SR610: Polyethylene glycol diacrylate, average molecular weight of the polyethylene glycol chain: 600 PGM-AC-4130Y: Silica sol surface-modified with a methacryloyl group-containing silane compound, dispersion medium: propylene glycol monomethyl ether Ominirad 184: 1-Hydroxy-cyclohexyl-phenyl-ketone

[0129] (Example 1) A 50-μm-thick PET film was used as the transparent substrate, and Composition 1 was coated on this PET film using a bar coater. Then, Composition 1 was photopolymerized to form a 5-μm-thick hard coat layer on the transparent substrate.

[0130] Next, the surface of the hard coat layer was surface-treated by glow discharge treatment with an electrode power density of 5500 W / m 2 Subsequently, on the hard coat layer, using a Si target and a Nb target as sputtering targets and a mixed gas of Ar gas and O2 gas, an adhesion layer and an optical functional layer were continuously formed by reactive sputtering. That is, on the hard coat layer, an adhesion layer composed of 3 nm of Si oxide (SiOx, 0 < x < 2) that may have oxygen deficiency, a first high refractive index material layer composed of 10 nm of Nb2O5, a first low refractive index material layer composed of 26 nm of SiO2, a second high refractive index material layer composed of 110 nm of Nb2O5, and a second low refractive index material layer composed of 85 nm of SiO2 were formed in this order.

[0131] Next, a 3 nm thick antifouling layer made of an alkoxysilane compound (KY1903-1, manufactured by Shin-Etsu Chemical Co., Ltd.) having a perfluoropolyether group was formed by vapor deposition on the SiO2 film of the topmost optical functional layer at a pressure of 0.01 Pa in the vapor deposition chamber, a vapor deposition temperature of 230°C, and a holding time of 7.2 s, thereby producing an optical laminate (anti-reflection film) of the example.

[0132] Example 2 The electrode power density during glow discharge treatment was 5500 W / m 2 to 1100W / m 2 An optical layered body was obtained in the same manner as in Example 1, except for changing the above.

[0133] Example 3 The electrode power density for glow discharge treatment was set to 5500 W / m 2 to 6600W / m 2 An optical layered body was obtained in the same manner as in Example 1, except for changing the above.

[0134] Example 4 An optical layered body was obtained in the same manner as in Example 1, except that the thickness of the hard coat layer formed on the transparent substrate was 2 μm.

[0135] Example 5 An optical layered body was obtained in the same manner as in Example 1, except that the composition for the hard coat layer was changed to Composition 2.

[0136] Example 6 An optical layered body was obtained in the same manner as in Example 1, except that the composition for the hard coat layer was changed to Composition 3.

[0137] Example 7 An optical laminate was obtained in the same manner as in Example 1, except that a 23 μm thick PET film was used as the transparent substrate instead of the 50 μm thick PET film.

[0138] Example 8 An optical laminate was obtained in the same manner as in Example 1, except that the thickness of the hard coat layer formed on the transparent substrate was 10 μm.

[0139] Example 9 The electrode power density during glow discharge treatment was 5500 W / m 2 to 3300W / m 2 An optical layered body was obtained in the same manner as in Example 8, except for changing the above.

[0140] Example 10 The electrode power density during glow discharge treatment was 5500 W / m 2 to 1100W / m 2 An optical layered body was obtained in the same manner as in Example 8, except for changing the above.

[0141] Example 11 The electrode power density during glow discharge treatment was 5500 W / m 2 to 550W / m 2 An optical layered body was obtained in the same manner as in Example 8, except for changing the above.

[0142] (Comparative Example 1) Composition 1 for forming the hard coat layer was changed to composition 4 shown in Table 1, and the electrode power density during glow discharge treatment was set to 5000 W / m 2 An optical layered body was obtained in the same manner as in Example 1, except that the above-mentioned conditions were met.

[0143] (Comparative Example 2) The thickness of the hard coat layer formed on the transparent substrate was set to 10 μm, and the electrode power density during glow discharge treatment was set to 5000 W / m 2 to 1100W / m 2 An optical layered body was obtained in the same manner as in Comparative Example 1, except for changing the above.

[0144] Next, the optical layered bodies obtained in Examples 1 to 11 and Comparative Examples 1 and 2 were measured and evaluated by the following methods.

[0145] <Bending test> As a sample, an optical laminate was cut into a size of 1 cm x 15 cm and prepared. It was confirmed that there were no cracks on the cut surface of the optical laminate. A 5.0 mm mandrel was set in a bending tester capable of setting a mandrel. The optical laminate described above was set in this tester so that the surface on which the antifouling layer was formed was bent outward. The tester was then bent over 2 seconds to bend the optical laminate 180° and held for 10 seconds. The presence or absence of cracks in the antifouling layer was then confirmed visually and under an optical microscope. The above procedure was repeated, changing the mandrel diameter to a smaller one every 0.2 mm, until abnormalities such as cracks were found on the surface of the antifouling layer side of the optical laminate both visually and under an optical microscope.The diameter (φmm) of the mandrel 0.2 mm larger than the diameter of the mandrel where the first crack was found was taken as the test result of the bending test. Similarly, measurements were also taken when the optical laminate was set in the above-mentioned testing machine so that the side on which the anti-fouling layer was formed was bent inward, and the test result of the bending test was determined to be the mandrel diameter (φmm) that was 0.2 mm larger than the mandrel diameter at which the first crack was discovered.

[0146] In addition, the theoretical elongation percentage S (%) of the optical functional layer was calculated when a mandrel with the smallest diameter at which no cracks occurred was used. The elongation percentage S was calculated as follows. S(%)={(R2 / R1)-1}×100 (where R2 is the distance from the axial center of the mandrel to the outer surface of the optical laminate, and R1 is the distance from the axial center of the mandrel to an imaginary line indicating a position corresponding to 1 / 2 of the total thickness of the optical laminate.)

[0147] In addition, when the surface on which the antifouling layer was formed was bent inward, the theoretical compression ratio C (%) of the optical functional layer was calculated using the mandrel with the smallest diameter that did not cause cracks. The compression ratio C was calculated as follows: C(%) = {1-(R3 / R1)} × 100 (where R3 is the distance from the axial center of the mandrel to the surface of the optical laminate on the antifouling layer side, and R1 is the distance from the axial center of the mandrel to an imaginary line indicating a position corresponding to 1 / 2 of the total thickness of the optical laminate.)

[0148] Three samples were prepared for each measurement, and each value was calculated as the average of the three measurements. The smallest mandrel diameter was 1.0φmm, and although 1.0φmm was used for measuring elongation, the results of the bending test were recorded as less than 1.0φmm because no cracks occurred.

[0149] <Martens hardness> Compositions 1 to 4 were used to prepare laminates (samples) each having a hard coat layer formed on a transparent substrate. For the optical laminates obtained in Examples 1 to 11 and Comparative Examples 1 and 2, the Martens hardness of the antifouling layer side of the optical laminate was measured. For laminates having only a hard coat layer formed thereon, the Martens hardness of the hard coat layer side of the laminate was measured. For the measurement, a microcompression tester (ENT-NEXUS, manufactured by Elionix, measuring indenter: Berkovich indenter) was used in accordance with ISO 14577-1. For the optical laminates, the hardness was measured at an indentation depth of 50 nm, and for laminates having only a hard coat layer formed thereon, the hardness was measured when indented to a depth of 1 / 10 the thickness of the hard coat layer. The Martens hardness of the optical laminate measured above was designated as (A), and the Martens hardness of the laminate in which only the hard coat layer was formed on the transparent substrate was designated as (B), and the ratio (A) / (B) was calculated. The results are shown in Table 2.

[0150] The optical layered bodies obtained in Examples 1 to 11 and Comparative Examples 1 and 2 were measured and evaluated by the following methods.

[0151] <Contact angle measurement test for pure water> Measurement was performed using an automatic contact angle meter DM-700 (manufactured by Kyowa Interface Science Co., Ltd.) by the ellipse 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℃ Pure water was dropped onto the laminate (sample), and the contact angle after 4 seconds was measured at any 6 points on the surface of the test piece, and the average value was taken as the pure water contact angle.

[0152] <Steel wool sliding test> Using a friction tester type I conforming to JIS L0849, the friction body was moved back and forth horizontally along the surface of the optical laminate (test piece) to obtain a test piece. Steel wool (#0000 manufactured by Bonstar Co., Ltd.) was used as the friction material. The test was set at a load of 1000 g / cm 2 The sliding distance was 50 mm, the sliding speed was 60 rpm (1 reciprocation / second), and the number of sliding cycles was 200 (100 reciprocations). After sliding, the sample was subjected to the same test as the contact angle measurement test for pure water described above, and the difference in contact angle before and after the test was determined. The results are shown in Table 3.

[0153] [Table 2]

[0154] [Table 3]

[0155] The results in Table 2 indicate that in all of Examples 1 to 7, the ratio ((A) / (B)) of the Martens hardness (A) of the antifouling layer side of the optical laminate to the Martens hardness (B) of the hard coat layer side of a laminate having only a transparent substrate and a hard coat layer was 3.6 or less, thereby achieving excellent hardness while further improving flex resistance. 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 more firmly bond the methacryloyl groups to the acrylate (binder resin), resulting in improved hardness of the optical laminate. Furthermore, it was found that the methacryloyl groups on the silica particle surfaces further improved adhesion between the hard coat layer and the adhesion layer, as well as between the hard coat layer and the optical functional layer via the adhesion layer, further improving flex resistance. Furthermore, in all of Examples 1 to 7, the difference in contact angle with water before and after rubbing, in which the steel wool was moved back and forth horizontally 200 times, was 20° or less. This suggests that the silica particles contained in the hard coat layer are surface-modified with methacryloyl groups derived from the methacryloyl group-containing silane compound, and that the methacryloyl groups are more firmly bonded to the acrylate (binder resin). As a result, it was found that the hardness of the optical laminate was improved, enabling excellent scratch resistance to be achieved.

[0156] Furthermore, from the results in Table 3, it was found that in all of Examples 8 to 11, the difference in contact angle with water before and after rubbing, in which the steel wool was horizontally reciprocated 200 times, was 20° or less, as in Examples 1 to 7, and the hardness of the optical laminate was improved, enabling excellent scratch resistance to be realized. Furthermore, the ratio ((A) / (B)) of the Martens hardness (A) of the antifouling layer side of the optical laminate to the Martens hardness (B) of the hard coat layer side of a laminate having only a transparent substrate and a hard coat layer was 3.6 or less, enabling further improvement in flex resistance while realizing excellent hardness.

[0157] On the other hand, in Comparative Example 1, when a hard coat layer was formed using Composition 4 containing unsurface-modified silica particles, the ratio ((A) / (B)) was 3.71, resulting in a low hardness of the laminate. Furthermore, the elongation rate S (outward bending) was 1.22, and the compression rate C (inward bending) was 4.4, resulting in poor flex resistance.

[0158] In Comparative Example 2, when a hard coat layer was formed using Composition 2 containing unsurface-modified silica particles, the difference in contact angle was 23.6°, indicating a decrease in scratch resistance. Furthermore, the elongation rate S (outward bending) was 1.29, and the compression rate C (inward bending) was 3.63, indicating poor flex resistance. [Explanation of symbols]

[0159] 10, 102...Optical laminate 11...Transparent base material 12...Hard coat layer 13...Adhesion layer 14...Optical functional layer 14a...High refractive index layer 14b...Low refractive index layer 15...Anti-fouling layer 20…Manufacturing equipment 1...Sputtering equipment 2A, 2B...Pretreatment equipment 3...Vapor deposition equipment 4...Roll unwinding device 5...Roll winding device 20…Manufacturing equipment 21...Vacuum pump 22...Guide roll 23...Unwinding roll 24...Take-up roll 25...Deposition roll 26...Can Roll 31, 32, 33, 34, 35…Chambers 41...Film forming section 42...Plasma discharge device 43...evaporation source 53...Heating device

Claims

1. An optical laminate having, in this order, a transparent substrate, a hard coat layer, an adhesion layer made of a sputtered film, a high refractive index layer made of a sputtered film, an optical functional layer in which low refractive index layers with a refractive index lower than the high refractive index layer are alternately laminated, and an anti-fouling layer, The thickness of the transparent substrate is 25 μm or more and 50 μm or less. The hard coat layer contains a surface-modified silica filler, A portion of the silica filler is exposed on the surface of the hard coat layer on the optical functional layer side. An optical laminate in which the surface modification of the silica filler surface exposed on the aforementioned surface has been removed.

2. The optical laminate according to claim 1, wherein the silica filler is surface-modified with functional groups derived from a silane compound.

3. The optical laminate according to claim 2, 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.

4. The optical laminate according to claim 2, wherein the silane compound is a (meth)acryloyl group-containing silane compound.

5. An optical laminate having in this order a transparent substrate, a hard coat layer, an adhesion layer made of a sputtered film, a high refractive index layer made of a sputtered film, an optical functional layer in which low refractive index layers having a refractive index lower than the high refractive index layer are alternately laminated, and an anti-fouling layer, The thickness of the transparent substrate is 25 μm or more and 50 μm or less. The hard coat layer contains silica filler, The silica filler is surface-modified with functional groups derived from silane compounds. An optical laminate in which the silane compound is a (meth)acryloyl group-containing silane compound.

6. The hard coat layer contains a binder resin and a silica filler. The optical laminate according to claim 2 or 5, wherein the functional group derived from the silane compound has the same functional group as the binder resin.

7. The binder resin contains a (meth)acrylate compound, The optical laminate according to claim 6, wherein the functional group derived from the silane compound is a (meth)acryloyl group.

8. The optical laminate according to claim 1 or 5, wherein the average particle size of the silica filler is 800 nm or less.

9. The optical laminate according to claim 1 or 5, wherein the thickness of the hard coat layer is 0.5 μm or more and 100 μm or less.

10. The optical laminate according to claim 1 or 5, wherein when the optical laminate is bent 180° so that the surface on which the anti-fouling layer is formed faces outward, the elongation rate S (%) of the optical functional layer, calculated by the following formula (1), satisfies 1.3 ≤ S, using the mandrel of the smallest diameter on which no cracks occur. S(%)={(R2 / R1)-1}×100...(1) (However, R2 is the distance from the axial center of the mandrel to the outer surface of the optical laminate, and R1 is the distance from the axial center of the mandrel to a virtual line indicating a position corresponding to half the total thickness of the optical laminate.)

11. The optical laminate according to claim 10, wherein when the optical laminate is bent 180° so that the surface on which the antifouling layer is formed faces inward, the compressibility ratio C (%) of the optical functional layer, calculated by the following formula (2), satisfies 4.5 ≤ C, using the mandrel of the smallest diameter on which no cracks occur. C (%) = {1-(R3 / R1)}×100...(2) (However, 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.)

12. An article comprising an optical laminate according to any one of claims 1 to 5.

Images