Optical laminate, article equipped therewith, and method for manufacturing an optical laminate

Abstract

To provide an optical laminate that can realize excellent abrasion resistance and further improves flex resistance.SOLUTION: An optical laminate 102 includes a transparent base material 11, a hard coat layer 12, an adhesive layer 13 made of a sputter film, an optical functional layer 14 in which a high refractive index layer made of the sputter film and a low refractive index layer having a lower refractive index than the high refractive index layer are laminated alternately, and an antifouling layer 15 in this order. 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)) between a Martens hardness (A) in a side of the optical laminate antifouling layer and a Martens hardness (B) in a side of the hard coat layer of the laminate having only the transparent base material and the hard coat layer is 3.6 or less. Condition 2: a contact angle difference for water between before friction and after friction in which a steel wool is reciprocated horizontally 200 times is 20° or less by using a friction testing machine using the steel wool conforming to JIS L0849.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical laminate. 、 This is the best item and method for manufacturing optical laminates In relation to this, an optical laminate used as an anti-reflective film, particularly suitable for displays that are bent or curved, such as flexible displays. 、 This is the best item and method for manufacturing optical laminates This concerns... [Background technology]

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

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

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

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-185597 [Patent Document 2] Japanese Patent Publication No. 2020-74019 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, while Patent Document 1 can improve the abrasion resistance and flexibility of hard coat films, it does not evaluate scratch resistance, leaving room for improvement. Furthermore, while Patent Document 2 describes how the flexibility of the anti-reflective film can be improved, the scratch resistance is inferior because the anti-reflective layer is made of resin.

[0007] The present invention has been made in view of the above problems, and provides an optical laminate that can achieve excellent scratch resistance and further improve flexibility. 、 This is the best item and method for manufacturing optical laminates The purpose is to provide. [Means for solving the problem]

[0008] To solve the above problems, this 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, 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 hard coat layer contains 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 compliant with JIS L0849 and steel wool, the difference in contact angle with water before friction and after friction by 200 horizontal reciprocating motions of the steel wool is 20° or less.

[0009] [2] The optical laminate according to [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 a vinyl group-containing silane compound, a (meth)acryloyl group-containing silane compound, an amino group-containing silane compound, an isocyanate group-containing silane compound, an isocyanurate group-containing silane compound, an epoxy group-containing silane compound, and a mercapto group-containing silane compound.

[0011] [4] The optical laminate according to [2] above, 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 [5] above, wherein the functional group derived from the silane compound is a (meth)acryloyl group.

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

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

[0016] [9] When the optical laminate is bent 180° so that the surface on which the antifouling layer is formed faces outward, the elongation rate S (%) of the optical functional layer calculated by the following formula (1) when using the mandrel with the minimum diameter without cracking satisfies 1.3 ≦ S. The optical laminate according to [1] above. 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.)

[0017]

[10] The optical laminate according to claim 9, wherein when the optical laminate is bent 180° such 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), when the mandrel of the smallest diameter on which no cracks occur is used, satisfies 4.5 ≤ C. 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.)

[0018]

[11] An article comprising an optical laminate as described in any of [1] to

[10] above. [Effects of the Invention]

[0019] According to the present invention, an optical laminate can be made that has excellent scratch resistance and further improved flexibility. 、 This is the best item and method for manufacturing optical laminates This will make it possible to provide this. [Brief explanation of the drawing]

[0020] [Figure 1] This is a cross-sectional view showing another example of the optical laminate of this embodiment. [Figure 2] This is a cross-sectional view showing another example of the optical laminate of this embodiment. [Figure 3] This is a schematic diagram illustrating an example of a manufacturing apparatus that can be used in the manufacturing method of the optical laminate according to this embodiment. [Modes for carrying out the invention]

[0021] This embodiment will now be described in detail with reference to the figures as appropriate. The drawings used in the following description may show enlarged versions of key features for convenience in order to clearly illustrate the features of the present invention, and the dimensional ratios of each component may differ from those in reality. The materials, dimensions, etc. exemplified in the following description are examples only, and the present invention is not limited to them. It can be implemented with appropriate modifications within the scope of achieving its effects.

[0022] [Optical laminate] Figure 1 is a cross-sectional view showing another example of the optical laminate according to this embodiment. The optical laminate 102 shown in Figure 1 is made up of a transparent substrate 11, a hard coat layer 12, an adhesion layer 13, an optical functional layer 14, and an anti-fouling layer 15, all of which are laminated in that order. The adhesion layer 13 is a layer that creates adhesion between the hard coat layer 12 and the optical functional layer 14. The optical functional layer 14 is a layer that exhibits optical functions. Optical functions are functions that control the properties of light, such as reflection, transmission, and refraction, and examples include anti-reflective functions, selective reflection functions, and lens functions. The optical functional layer 14 preferably includes one selected from an anti-reflective layer and a selective reflective layer. Known materials can be used as the anti-reflective layer and the selective reflective layer. The anti-reflective layer and the selective reflective layer may both be single layers or laminates of multiple layers.

[0023] Figure 2 is a cross-sectional view showing another example of the optical laminate according to this embodiment. The optical laminate 101 shown in Figure 2 is provided with an anti-reflective layer as the optical functional layer 14 in the optical laminate 102 shown in Figure 1. The optical functional layer 14 (anti-reflective layer), as shown in Figure 1, consists of a laminate in which low refractive index layers 14b and high refractive index layers 14a are alternately laminated. The optical functional layer 14 shown in Figure 1 is laminated in the following order from the transparent substrate 11 side: hard coat layer 12, adhesion layer 13, high refractive index layer 14a, low refractive index layer 14b, high refractive index layer 14a, low refractive index layer 14b, and anti-fouling layer 15. Therefore, the anti-fouling layer 15 is in contact with the low refractive index layer 14b of the optical functional layer 14.

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

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

[0026] The transparent substrate 11 may contain a reinforcing material, provided that it does not significantly impair the optical properties. Examples of reinforcing materials include cellulose nanofibers and nanosilica. In particular, polyester resins, acetate resins, polycarbonate resins, and polyolefin resins are preferably used as reinforcing materials. Specifically, triacetylcellulose (TAC) substrates are preferably used as reinforcing materials. Furthermore, an inorganic substrate such as glass film can also be used for the transparent substrate 11.

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

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

[0029] The thickness of the transparent substrate 11 is not particularly limited, but is preferably 25 μm or more. The film thickness of the transparent substrate 11 is more preferably 40 μm or more. If 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, if 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 it reduces manufacturing concerns. If the thickness of the transparent substrate 11 is 40 μm or more, wrinkles are even less likely to occur, which is preferable.

[0030] When manufacturing is carried out using a roll, the thickness of the transparent substrate 11 is 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 manufacturing and the optical laminate 10 after manufacturing can be easily wound into a roll, and the optical laminate 10 can be manufactured efficiently. Furthermore, when the thickness of the transparent substrate 11 is 1000 μm or less, it becomes possible to make the optical laminate 10 thinner and lighter. When the thickness of the transparent substrate 11 is 600 μm or less, the optical laminate 10 can be manufactured more efficiently, and further thinning and weight reduction is possible, which is preferable.

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

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

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

[0034] Examples of ionizing radiation-curable resins used in the binder resin of the hard coat layer 12 include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, and N-vinylpyrrolidone. Furthermore, examples of compounds that are ionizing radiation-curable resins having two or more unsaturated bonds include trimethylolpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. Examples of polyfunctional compounds include lysritol penta(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, isocyanuric acid tri(meth)acrylate, isocyanuric acid di(meth)acrylate, polyester tri(meth)acrylate, polyester di(meth)acrylate, bisphenol di(meth)acrylate, diglycerin tetra(meth)acrylate, adamantyl di(meth)acrylate, isobolonyl di(meth)acrylate, dicyclopentane di(meth)acrylate, tricyclodecane di(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate. Among these, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), and pentaerythritol tetraacrylate (PETTA) are preferably used. Note that "(meth)acrylate" refers to both methacrylate and acrylate. Furthermore, as ionizing radiation-curable resins, compounds modified with PO (propylene oxide), EO (ethylene oxide), CL (caprolactone), etc., can also be used. Urethane (meth)acrylate oligomers and epoxy (meth)acrylate oligomers can also be used from the viewpoint of hard coat film formation and viscoelasticity adjustment.

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

[0036] The hard coat layer 12 includes, for example, a binder resin and silica particles as a filler. Preferably, the silica particles include silica particles that have been surface-modified beforehand. 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 individually or in combination. The silane compound is appropriately selected according to the type of binder resin, but if the binder resin contains functional groups, a silane compound having the same functional groups as the binder resin is preferred. For example, if the binder resin contains a (meth)acrylate compound as an ionizing radiation-curable resin, a (meth)acryloyl group-containing alkoxysilane compound is preferred. Note that "(meth)acrylate" refers to methacrylate and / or acrylate. Furthermore, in this invention, methacrylate and acrylate are treated as the same substance in terms of their reaction mechanisms. The silane compounds used for surface modification preferably have alkoxysilyl or silanol groups at their termini, as this allows for good bonding with hydroxyl groups present on the silica particle surface. The pre-surface modification of the silica particles improves their dispersibility in the binder resin, and the reaction between the surface treatment agent used for surface modification and the binder resin strengthens the bond between the silica particles and 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 optical functional layer 14 side. In this case, the hard coat layer 12 and the optical functional layer 14 are more strongly bonded via the adhesion layer 13. Methods for exposing the particles include glow treatment, which will be described later, in which case any surface modifications on the exposed silica surface are removed. When the filler is exposed on the hard coat layer surface, and the surface modification is removed at that time, an electrostatic attraction is generated between the hydroxyl groups formed on the filler surface and the adhesion layer 13, which will be described later, thereby improving adhesion. In addition, the exposed filler also contributes to improved adhesion by biting into the adhesion layer 13 as an anchor. The improvement in flexural resistance occurs through a combination of the bonding with the binder resin due to the aforementioned surface modification of the silica surface 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 becomes a so-called clear type anti-reflective film.

[0038] The hard coat layer 12 is preferably subjected to treatments such as glow discharge treatment, plasma treatment, ion etching, or alkaline treatment on its surface. Among these, glow discharge treatment is preferred because it allows for large-area treatment. The intensity of the glow discharge treatment is, for example, 100 W / m² as the electrode power density. 2 ~11000W / m 2 This can be done with 1600W / m 2 ~7000W / m 2 It is preferable to do so. By performing glow discharge treatment on the surface of the hard coat layer 12, the surface of the hard coat layer 12 is roughened at the nanoscale, and weakly bonding substances present on the surface of the hard coat layer 12 are removed. As a result, the adhesion between the hard coat layer 12 and the adhesion layer 13 formed on the hard coat layer 12 is improved. There is also the effect of exposing silica particles from the hard coat layer 12. Furthermore, while increasing the intensity during discharge treatment tends to improve the flexibility resistance described later, this effect plateaus above a certain discharge intensity, and excessive glow discharge intensity can lead to deterioration of the resin constituting the hard coat layer. Therefore, it is preferable to perform glow discharge treatment at the aforementioned range of discharge intensity.

[0039] Furthermore, 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. Organic fine particles such as acrylic resin are preferably used as fillers of this size. When the particle size of the filler is within this range, the overall haze value of the optical laminate 10 will exceed 2%. An optical laminate 10 with a haze of over 2% has anti-glare properties and becomes a so-called anti-glare (AG) type anti-reflective 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. Various reinforcing materials can be used as fillers in the hard coat layer 12 to impart toughness to the hard coat layer 12, provided that they do not impair the optical properties. 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. If the thickness of the hard coat layer 12 is 0.5 μm or more, sufficient hardness is obtained, making it less likely for scratches to occur during manufacturing. Also, if the thickness of the hard coat layer 12 is 100 μm or less, it becomes possible to make the optical laminate 10 thinner and lighter. In addition, if 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 manufacturing are less likely to occur, resulting in good productivity.

[0041] The hard coat layer 12 may be a single layer or a laminate of multiple layers. Furthermore, the hard coat layer 12 may be provided with known functions such as ultraviolet absorption performance, antistatic performance, refractive index adjustment function, and hardness adjustment function. Furthermore, the function provided to the hard coat layer 12 may be provided within a single hard coat layer, or it may be provided by dividing it into multiple 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 Figure 2, the adhesion layer 13 is provided between the hard coat layer 12 and the optical functional layer 14. The adhesion layer 13 has the function of bringing the hard coat layer 12 and the optical functional layer 14 into close contact. The adhesion layer 13 is preferably made of an oxygen-deficient metal oxide or metal. An oxygen-deficient metal oxide refers to a metal oxide in which the number of oxygen atoms is insufficient compared to the stoichiometric composition. Examples of oxygen-deficient metal oxides include SiOx, AlOx, TiOx, ZrOx, CeOx, MgOx, ZnOx, TaOx, SbOx, SnOx, and MnOx. Examples of metals include Si, Al, Ti, Zr, Ce, Mg, Zn, Ta, Sb, Sn, Mn, and In. The adhesion layer 13 may, for example, be a material in which x in SiOx is greater than 0 and less than 2.0. Furthermore, the adhesion layer may be formed from a mixture of multiple metals or metal oxides. From the viewpoint of maintaining transparency and adhesion with the optical functional layer and obtaining good optical properties, the thickness of the adhesion layer is preferably greater than 0 nm and less than or equal to 20 nm, and particularly preferably between 1 nm and 10 nm.

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

[0044] In the optical laminate 10 shown in Figure 2, the optical functional layer 14 consists of a laminate in which low refractive index layers 14b and high refractive index layers 14a are alternately stacked. Therefore, light incident from the antifouling layer 15 side interferes with each other through the optical functional layer 14, reducing the intensity of reflected light and enabling an anti-reflective function. Thus, an anti-reflective function is obtained that prevents light incident from the antifouling layer 15 side from being reflected in one direction.

[0045] The low refractive index layer 14b contains, for example, a metal oxide. The low refractive index layer 14b may also contain an oxide of Si from the standpoint of availability and cost, and is preferably a layer mainly composed of SiO2 (an oxide of Si). The SiO2 monolayer film is colorless and transparent. In this embodiment, the main component of the low refractive index layer 14b means a component that is present in the low refractive index layer 14b at a concentration of 50% by mass or more. If the low refractive index layer 14b is a layer mainly composed of Si oxide, it may contain other elements in an amount of less than 50% by mass. The content of elements other than Si oxide is preferably 10% or less. Examples of other elements include Na for the purpose of improving durability, Zr, Al, and N for the purpose of improving hardness, and Zr and Al for the purpose of improving alkali resistance.

[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 dielectric materials 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 dielectrics used in 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 you want to impart conductive properties to the high refractive index layer 14a, you can choose materials such as ITO or indium zinc oxide (IZO).

[0048] For example, the optical functional layer 14 preferably uses 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 thickness of the low refractive index layer 14b can be in the range of 1 nm to 200 nm, and can be appropriately selected depending on the wavelength range in which anti-reflective function is required. The thickness of the high refractive index layer 14a can be, for example, between 1 nm and 200 nm, and can be appropriately selected depending on the wavelength range in which anti-reflective properties are required. The film thicknesses of the high refractive index layer 14a and the low refractive index layer 14b can be appropriately selected according to the design of the optical functional layer 14. For example, starting from the adhesion layer 13 side, the layers can be arranged in the following order: a high refractive index layer 14a of 5-50 nm, a low refractive index layer 14b of 10-80 nm, another high refractive index layer 14a of 20-200 nm, and a third low refractive index layer 14b of 50-200 nm.

[0050] Of the layers forming the optical functional layer 14, a low refractive index layer 14b is arranged on the side facing the antifouling layer 15. When the low refractive index layer 14b of the optical functional layer 14 is in contact with the antifouling layer 15, the anti-reflective performance of the optical functional layer 14 is improved, which is preferable.

[0051] The anti-fouling layer 15 is formed on the outermost surface of the optical functional layer 14 and prevents contamination of the optical functional layer 14. In addition, when applied to touch panels, etc., the anti-fouling layer 15 suppresses wear of the optical functional layer 14 due to its abrasion resistance. The antifouling layer 15 in this embodiment consists of a vapor-deposited film formed by depositing an antifouling material. In this embodiment, the antifouling layer 15 is formed by vacuum-depositing a fluorine-based organic compound as an antifouling material onto one surface of the low refractive index layer 14b that constitutes the optical functional layer 14. In this embodiment, because the antifouling material contains a fluorine-based organic compound, the optical laminate 10 has even better abrasion resistance and alkali resistance.

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

[0053] When a fluorine-based organic compound comprising a fluorine-modified organic group and a reactive silyl group (e.g., alkoxysilane) is used as the antifouling layer 15, and when SiO2 is used as the low refractive index layer 14b of the optical functional layer 14 that is 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. Therefore, good adhesion between the optical functional layer 14 and the antifouling layer 15 is achieved, 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, 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 applied to touch panel applications, etc. If the thickness of the antifouling layer 15 is 3 nm or more, the liquid resistance of the optical laminate 10 is improved. Furthermore, if the thickness of the antifouling layer 15 is 20 nm or less, the time required for deposition is shortened, and manufacturing can be done efficiently.

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

[0056] Furthermore, in the optical laminates 10 and 102 configured as described above, a friction tester using steel wool conforming to JIS L0849 was used, and the difference in contact angle with water before friction and after friction in which the steel wool was moved horizontally 200 times was 20° or less (Condition 2). If the hardness of the optical laminates 10 and 102 is high, the above contact angle difference will be 20° or less, and excellent scratch resistance can be achieved.

[0057] In the optical laminates 10,102 configured as described above, when the optical laminates 10,102 are bent 180° so that the surface on which the anti-fouling layer 15 is formed faces outward, the elongation rate S (%) of the optical functional layer 14, calculated by the following formula (1), is preferably 1.3 ≤ S, when using the mandrel of the smallest diameter that does not cause cracks. This further improves the bending resistance of the optical laminates 10,102. 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.)

[0058] Furthermore, in the optical laminates 10,102, when the optical laminates 10,102 are bent 180° so that the surface on which the anti-fouling layer 15 is formed faces inward, the compressibility ratio C (%) of the optical functional layer 14, calculated by the following formula (2), when using the mandrel with the smallest diameter that does not cause cracks, preferably satisfies 4.5 ≤ C, and more preferably satisfies 5 ≤ ​​C. This further improves the bending resistance of the optical laminates 10,102. 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.)

[0059] Furthermore, it is preferable that the optical functional layer 14 satisfies both the above range for elongation S(%) and the above range for compressibility C(%). That is, in the optical laminates 10,102, when the optical laminates 10,102 are 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 formula (1) below, using the smallest diameter mandrel that does not cause cracks, satisfies 1.3 ≤ S, and when the optical laminates 10,102 are bent 180° so that the surface on which the antifouling layer 15 is formed faces inward, the compressibility C(%) of the optical functional layer 14 calculated by formula (2) above, using the smallest diameter mandrel that does not cause cracks, satisfies 4.5 ≤ C. This further improves the bending resistance of the optical laminates 10,102.

[0060] The elongation rates mentioned above are based on a PET substrate with a thickness of 50 μm; these values ​​may vary if the thickness is reduced.

[0061] In the optical laminates 10, 102 configured as described above, when the thickness of the hard coat layer of the optical laminate is 5 μm, and the optical laminates 10, 102 are bent 180° so that the surface on which the anti-fouling layer 15 is formed faces outward, the diameter of the mandrels is gradually reduced, and it is preferable that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel in which the crack is first discovered is 4.0 φ mm or less, more preferably 3.5 φ mm or less, and even more preferably 3.0 φ mm or less.

[0062] Furthermore, when the hard coat layer of the optical laminate is 5 μm thick, and the optical laminates 10 and 102 are bent 180° so that the surface on which the anti-fouling layer 15 is formed faces inward, the diameter of the mandrels is gradually reduced, and it is preferable that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel in which the crack is first discovered is 1.1 mm or less, and more preferably less than 1.0 mm.

[0063] Furthermore, when the hard coat layer of the optical laminate is 5 μm thick, and the optical laminates 10, 102 are bent 180° so that the surface with the antifouling layer 15 is facing outwards, it is preferable that the diameter of the mandrel is gradually reduced until the diameter of the mandrel in which the crack was first discovered is 0.2 mm larger than the diameter of the mandrel in which the crack was first discovered is 4.0 mm in diameter or less, and it is even more preferable that when the optical laminates 10, 102 are bent 180° so that the surface with the antifouling layer 15 is facing inwards, the diameter of the mandrel is gradually reduced until the diameter of the mandrel in which the crack was first discovered is 0.2 mm larger than the diameter of the mandrel in which the crack was first discovered is 1.1 mm in diameter or less.

[0064] In the optical laminates 10, 102 configured as described above, when the thickness of the hard coat layer of the optical laminate is 10 μm, and the optical laminates 10, 102 are bent 180° so that the surface on which the anti-fouling layer 15 is formed faces outward, the diameter of the mandrels is gradually reduced, and it is preferable that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel in which the crack is first discovered is 4.0 φ mm or less, more preferably 3.5 φ mm or less, and even more preferably 3.0 φ mm or less.

[0065] Furthermore, when the hard coat layer of the optical laminate is 10 μm thick, and the optical laminates 10 and 102 are bent 180° so that the surface on which the anti-fouling layer 15 is formed faces inward, the diameter of the mandrels is gradually reduced, and it is preferable that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel in which the crack is first discovered is 1.4 mm or less, and more preferably 1.2 mm or less.

[0066] Furthermore, when the hard coat layer of the optical laminate is 10 μm thick, and the optical laminate 10,102 is bent 180° so that the surface with the antifouling layer 15 is facing outwards, it is preferable that the diameter of the mandrel is gradually reduced until the diameter of the mandrel in which the crack was first discovered is 0.2 mm larger than the diameter of the mandrel in which the crack was first discovered is 4.0 mm in diameter or less, and it is even more preferable that when the optical laminate 10,102 is bent 180° so that the surface with the antifouling layer 15 is facing inwards, the diameter of the mandrel is gradually reduced until the diameter of the mandrel in which the crack was first discovered is 0.2 mm larger than the diameter of the mandrel in which the crack was first discovered is 1.4 mm in diameter or less.

[0067] In the optical laminates 10, 102 configured as described above, when the thickness of the hard coat layer of the optical laminate is 2 μm, and the optical laminates 10, 102 are bent 180° so that the surface on which the anti-fouling layer 15 is formed faces outward, the diameter of the mandrels is gradually reduced, and it is preferable that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel in which the crack is first discovered is 4.0 φ mm or less, more preferably 3.5 φ mm or less, and even more preferably 3.0 φ mm or less.

[0068] Furthermore, when the hard coat layer of the optical laminate is 2 μm thick, and the optical laminates 10 and 102 are bent 180° so that the surface on which the anti-fouling layer 15 is formed faces inward, the diameter of the mandrels is gradually reduced, and it is preferable that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel in which the crack is first discovered is 1.1 mm or less, and more preferably less than 1.0 mm.

[0069] Furthermore, when the hard coat layer of the optical laminate is 2 μm thick, and the optical laminates 10, 102 are bent 180° so that the surface with the antifouling layer 15 is facing outwards, it is preferable that the diameter of the mandrel is gradually reduced until the diameter of the mandrel in which the crack was first discovered is 0.2 mm larger than the diameter of the mandrel in which the crack was first discovered is 4.0 mm in diameter or less, and it is even more preferable that when the optical laminates 10, 102 are bent 180° so that the surface with the antifouling layer 15 is facing inwards, the diameter of the mandrel is gradually reduced until the diameter of the mandrel in which the crack was first discovered is 0.2 mm larger than the diameter of the mandrel in which the crack was first discovered is 1.1 mm in diameter or less.

[0070] The mandrel diameter mentioned above should be calculated by cutting out three pieces from the same sample, measuring them, and averaging the results of the three measurements.

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

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

[0073] In the manufacturing method of the optical laminate 10 of this embodiment, it is preferable that the first surface treatment step, the adhesion layer formation step, the optical functional layer formation step, the second surface treatment step, and the antifouling layer formation step be carried out continuously while maintaining the optical laminate in the process of manufacturing under reduced pressure. When the first surface treatment step, the adhesion layer formation step, the optical functional layer formation step, the second surface treatment step, and the antifouling layer formation step are carried out continuously while maintaining the optical laminate in the process of manufacturing under reduced pressure, for example, an apparatus equipped with a thin film forming apparatus as described in Patent Document 4 can be used as a sputtering apparatus.

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

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

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

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

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

[0079] <Sputtering equipment> The sputtering apparatus 1 shown in Figure 3 comprises a chamber 31 whose interior is kept under a predetermined reduced pressure atmosphere, one or more vacuum pumps 21 (two in Figure 3) that discharge the gas from the chamber 31 to create a reduced pressure atmosphere, a film deposition roll 25, a plurality (two in Figure 4) of guide rolls 22, and a plurality (four in the example shown in Figure 3) of film deposition units 41. As shown in Figure 3, the film deposition roll 25, the guide rolls 22, and the film deposition units 41 are installed inside the chamber 31. As shown in Figure 3, the chamber 31 is connected to the chamber 32 of the pretreatment apparatus 2B.

[0080] The film-forming roll 25 and guide roll 22 transport the transparent substrate 11 with the hard coat layer 12 formed on its surface, which has been sent from the pre-treatment device 2A, at a predetermined transport speed, and supply the transparent substrate 11 with the adhesion layer 13 and 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 onto the hard coat layer 12 of a transparent substrate 11 that runs on a film-forming roll 25, and then a high refractive index layer 14a and a low refractive index layer 14b are alternately laminated on top of that to form an optical functional layer 14.

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

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

[0083] The target material, and the type and flow rate of the reactive gas are appropriately determined according to the composition of the adhesion layer 13, high refractive index layer 14a, and low refractive index layer 14b formed on the transparent substrate 11 by passing between the film formation section 41 and the film formation roll 25. For example, when forming a layer made of SiO2, Si is used as the target and O2 is used as the reactive gas. Also, 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 of less than 0.5 Pa, and the high refractive index layer 14a is preferably formed at a vacuum of less than 1.0 Pa. When these layers are formed at the vacuum levels, the optical functional layer 14 becomes denser, the water vapor transmittance decreases, and durability and other properties are improved.

[0084] In this embodiment, from the viewpoint of increasing the film deposition rate, it is preferable to use magnetron sputtering as the sputtering method. Furthermore, the sputtering method is not limited to the magnetron sputtering method; other methods such as a two-electrode sputtering method using plasma generated by DC glow discharge or high frequency, or a three-electrode sputtering method with the addition of a hot cathode may also be used.

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

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

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

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

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

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

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

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

[0093] The vacuum pump 21 provided in the manufacturing apparatus 20 shown in Figure 4 can be, for example, a dry pump, an oil rotary pump, a turbomolecular pump, an oil diffusion pump, a cryopump, a sputter ion pump, or a getter pump. The vacuum pump 21 can be appropriately selected or used in combination in each chamber 31, 32, 33, 34, and 35 to create the desired reduced pressure state.

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

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

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

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

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

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

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

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

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

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

[0104] When an electrical discharge treatment is performed on the surface of the optical functional layer 14, the surface of the optical functional layer 14 is etched, and the surface state of the optical functional layer 14 changes. The surface state of the optical functional layer 14 is expressed by the surface roughness Ra or the average element length RSm. For example, in the case of a clear type anti-reflective film with a haze of 2.0 or less, the surface state of the optical functional layer 14 is easily defined by the surface roughness Ra. Also, for example, in the case of an AG type anti-reflective film with a haze greater than 2.0, the surface state of the optical functional layer 14 is easily defined by the average element length RSm. The surface roughness Ra and the average element length RSm are measured in accordance with JIS B0601 (ISO4287).

[0105] Subsequently, the transparent substrate 11, whose surface has been treated with the optical functional layer 14, is fed to the vapor deposition apparatus 3 by the rotation of the can roll 26 and guide roll 22. Next, the antifouling layer formation process is performed in the chamber 33 of the vapor deposition apparatus 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 process, is kept under reduced pressure without being exposed to the atmosphere, and the antifouling layer formation process is performed continuously. In the antifouling layer formation process, the guide roll 22 is rotated to transport the transparent substrate 11, on which the surface of the optical functional layer 14 has been treated, at a predetermined transport speed, while the deposition source 43 is 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 its vapor pressure temperature by a heating device 53, and the resulting evaporated gas is supplied from a deposition source 43 under a reduced pressure environment and deposited onto the surface-treated optical functional layer 14 to form the antifouling layer 15 by vacuum deposition. The pressure used when vacuum deposition of the antifouling layer 15 is preferably 0.05 Pa or less, more preferably 0.01 Pa or less, and particularly preferably 0.001 Pa or less. When the pressure used during vacuum deposition is reduced to 0.05 Pa or less, the mean free path of the film-forming molecules is longer and the deposition energy is higher, resulting in a denser and better antifouling layer 15.

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

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

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

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

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

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

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

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

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

[0116] In this embodiment, the example described was a case in which an optical laminate 10 is continuously manufactured using a roll-to-roll method with a manufacturing apparatus 20 shown in Figure 3, which includes a pre-processing apparatus 2A, a sputtering apparatus 1, a pre-processing apparatus 2B, a 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 apparatuses 2A and 2B, but instead consists of a roll unwinding apparatus 4, a sputtering apparatus 1, a deposition apparatus 3, and a roll winding apparatus 5 connected in that order.

[0117] The manufacturing apparatus 20 shown in Figure 3 may include a pretreatment chamber (not shown) between the chamber 33 of the 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 formed. The manufacturing apparatus 20 shown in Figure 3 may include a post-processing 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] The manufacturing apparatus 20 shown in Figure 3 may include a hard coat layer forming apparatus between the roll unwinding apparatus 4 and the sputtering apparatus 1 for forming a hard coat layer 12 on the surface of the transparent substrate 11. In this case, not only the optical functional layer 14 and the antifouling layer 15, but also the hard coat layer 12 can be manufactured continuously using a roll-to-roll method, which is preferable.

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

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

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

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

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

[0124] Although embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. For example, instead of the hard coat layer 12, an anti-glare layer can be formed, or any functional layer such as a flexible soft coat layer can be added as needed. These layers may be laminated. [Examples]

[0125] The following describes embodiments of the present invention. Note that the optical laminates created in the following embodiments and comparative examples are examples of structures that function as anti-reflective films, and the spirit of the present invention is not limited to these.

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

[0127] [Table 1]

[0128] CN968: Hexafunctional aliphatic urethane acrylate having a polyester backbone SR610: Polyethylene glycol diacrylate, average molecular weight of 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 applied onto this PET film using a bar coater. Subsequently, 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 using 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 made of Si oxide (SiOx, 0 < x < 2) that may have oxygen deficiency with a thickness of 3 nm, a first high refractive index material layer made of Nb2O5 with a thickness of 10 nm, a first low refractive index material layer made of SiO2 with a thickness of 26 nm, a second high refractive index material layer made of Nb2O5 with a thickness of 110 nm, and a second low refractive index material layer made of SiO2 with a thickness of 85 nm 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 on the uppermost layer of the optical functional layer at an internal 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, and an optical laminate (anti-reflection film) of the example was produced.

[0132] (Example 2) An optical laminate was obtained in the same manner as in Example 1, except that the electrode power density during the glow discharge treatment was changed from 5500 W / m 2 to 1100 W / m 2 .

[0133] (Example 3) An optical laminate was obtained in the same manner as in Example 1, except that the electrode power density of the glow discharge treatment was changed from 5500 W / m 2 to 6600 W / m 2 .

[0134] (Example 4) 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 set to 2 μm.

[0135] (Example 5) An optical laminate 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 laminate 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 the 50-μm thick PET film was replaced with a 23-μm thick PET film as the transparent substrate.

[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 set to 10 μm.

[0139] (Example 9) The electrode power density during glow discharge processing is 5500 W / m². 2 From 3300W / m 2 An optical laminate was obtained in the same manner as in Example 8, except for the change made to [specific component].

[0140] (Example 10) The electrode power density during glow discharge processing is 5500 W / m². 2 From 1100W / m 2 An optical laminate was obtained in the same manner as in Example 8, except for the change made to [specific component].

[0141] (Example 11) The electrode power density during glow discharge processing is 5500 W / m². 2 From 550W / m 2 An optical laminate was obtained in the same manner as in Example 8, except for the change made to [specific component].

[0142] (Comparative Example 1) By changing composition 1, which forms the hard coat layer, to composition 4 shown in Table 1, the electrode power density during glow discharge treatment is increased to 5000 W / m². 2 An optical laminate was obtained in the same manner as in Example 1, except for the aforementioned difference.

[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 / m². 2 From 1100W / m 2 An optical laminate was obtained in the same manner as in Comparative Example 1, except for the change made to [specific component].

[0144] Next, the optical laminates obtained in Examples 1-11 and Comparative Examples 1-2 were measured and evaluated using the following methods.

[0145] <Bending Test> As a sample, an optical laminate cut to 1 cm x 15 cm was prepared. The optical laminate was confirmed to have no cracks on the cut surface. A 5.0 mm mandrel was set in a bending test machine capable of accommodating a mandrel. The aforementioned optical laminate was placed in this machine so that the side with the antifouling layer formed on it was bent outwards. The optical laminate was then bent 180° by bending the test machine over 2 seconds and held for 10 seconds. After that, the presence or absence of cracks in the antifouling layer was checked visually and with an optical microscope. The above procedure was repeated, changing the mandrel diameter by 0.2 mm every so far, until cracks or other abnormalities were observed on the surface of the antifouling layer of the optical laminate by visual inspection and under an optical microscope. The diameter (φ mm) of the mandrel that was 0.2 mm larger than the diameter of the mandrel in which the first crack was found was used as the test result for the bending test. Similarly, measurements were taken when the optical laminate was set in the aforementioned testing machine so that the surface with the anti-fouling layer was bent inward. The diameter of the mandrel (φmm) that was 0.2 mm larger than the diameter of the mandrel in which the first crack was discovered was used as the test result for the bending test.

[0146] Furthermore, the theoretical elongation rate S (%) of the optical functional layer was calculated using the smallest diameter mandrel in which no cracks occurred. The elongation rate S was calculated as follows: S(%) = {(R2 / R1)-1} × 100 (However, R2 is the distance from the axis center of the mandrel to the outer surface of the optical laminate, and R1 is the distance from the axis center of the mandrel to a virtual line indicating a position corresponding to half the total thickness of the optical laminate.)

[0147] Furthermore, the theoretical compressibility C (%) of the optical functional layer was calculated when the surface with the antifouling layer was set to be folded inward, using the smallest diameter mandrel in which no cracks occurred. The compressibility C was calculated as follows: C(%) = {1 - (R3 / R1)} × 100 (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.)

[0148] For the measurements, three samples were prepared for each type of sample, and each value was calculated from the average of the three measurements. The smallest mandrel diameter was 1.0 mm, and this was used for measuring elongation. However, since no cracks occurred, the bending test results were recorded as less than 1.0 mm.

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

[0150] Furthermore, the optical laminates obtained in Examples 1-11 and Comparative Examples 1-2 were measured and evaluated using the following methods.

[0151] <Contact angle measurement test with pure water> A fully automatic contact angle meter DM-700 (manufactured by Kyowa Interface Chemical Co., Ltd.) was used to measure the contact angle using the elliptic fitting method under the following conditions. Pure water was placed in a glass syringe, a stainless steel needle was attached to the tip, and the pure water was dropped onto the optical laminate (test specimen). Amount of pure water to be added: 2.0 μL Measurement temperature: 25℃ The contact angle of the laminate (sample) was measured at six arbitrary locations on the surface of the test piece after 4 seconds of dropping pure water onto it, and the average value was defined as the pure water contact angle.

[0152] <Steel wool sliding test> Using a Type I friction tester compliant with JIS L0849, a friction element was moved horizontally back and forth along the surface of an optical laminate (test specimen) to obtain a test specimen. Steel wool (Bonstar Co., Ltd., #0000 grade) was used as the friction material. The test setting was a load of 1000 g / cm². 2 The sliding distance was set to 50 mm, the sliding speed to 60 rpm (1 cycle / second), and the number of sliding cycles to 200 (100 cycles). The same test as the contact angle measurement test for pure material described above was performed on the sample after sliding, 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] From the results in Table 2, in all of Examples 1 to 7, the ratio ((A) / (B)) of the Martens hardness (A) on the antifouling layer side of the optical laminate to the Martens hardness (B) on the hard coat layer side of the laminate having only a transparent substrate and a hard coat layer was 3.6 or less, indicating that excellent hardness can be achieved while further improving flexibility. In particular, it was found that the silica particles contained in the hard coat layer are surface-modified with methacryloyl groups derived from a methacryloyl group-containing silane compound, which is thought to result in a stronger bond between the methacryloyl groups and the acrylate (binder resin), thereby improving the hardness of the optical laminate. Furthermore, it was found that the methacryloyl groups on the surface of the silica particles further improve the adhesion between the hard coat layer and the adhesion layer, and between the optical functional layer via the adhesion layer, further improving flexibility. Furthermore, in all of Examples 1 to 7, the difference in contact angle with water before friction and after friction by 200 horizontal reciprocating motions of the steel wool was 20° or less. This suggests that the silica particles contained in the hard coat layer are surface-modified with methacryloyl groups derived from methacryloyl group-containing silane compounds, resulting in stronger bonding of the methacryloyl groups to the acrylate (binder resin). As a result, the hardness of the optical laminate is improved, and excellent scratch resistance can be achieved.

[0156] Furthermore, the results in Table 3 show that in all of Examples 8 to 11, similar to Examples 1 to 7, the difference in contact angle with water before friction and after friction with steel wool reciprocated horizontally 200 times was 20° or less, indicating that the hardness of the optical laminate was improved and excellent scratch resistance could be achieved. In addition, the ratio ((A) / (B)) of the Martens hardness of the antifouling layer side of the optical laminate (A) to the Martens hardness of the hard coat layer side of the laminate having only a transparent substrate and a hard coat layer (B) was 3.6 or less, indicating that excellent hardness could be achieved while further improving flexibility.

[0157] On the other hand, in Comparative Example 1, when a hard coat layer was formed using composition 4 containing unmodified silica particles, the above ratio ((A) / (B)) became 3.71, resulting in a lower hardness of the laminate. Furthermore, the elongation S (outer bending) was 1.22 and the compressibility C (inner bending) was 4.4, indicating poor bending resistance.

[0158] In Comparative Example 2, when a hard coat layer was formed using composition 2 containing unmodified silica particles, the contact angle difference was 23.6°, indicating a decrease in scratch resistance. Furthermore, the elongation S (outward bending) was 1.29 and the compressibility C (inward bending) was 3.63, indicating poor bending resistance. [Explanation of Symbols]

[0159] 10, 102...Optical laminate 11...Transparent base material 12…Hard court layer 13…Intimate layer 14...Optical functional layer 14a... High refractive index layer 14b... Low refractive index layer 15… Anti-fouling layer 20…Manufacturing equipment 1…Sputtering device 2A, 2B... Pre-treatment devices 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... Reel roll 25…Film deposition roll 26... Canroll 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. The surface modification of the silica filler surface exposed on the aforementioned surface has been removed. 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 that conforms to JIS L0849 and uses steel wool, the difference in contact angle with water before friction and after friction by moving the steel wool horizontally back and forth 200 times is 20° or less.

2. The optical laminate according to claim 1, wherein the silica 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. The hard coat layer contains a binder resin and a silica filler. The optical laminate according to claim 2, wherein the functional group derived from the silane compound has the same functional group as the binder resin.

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

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

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

9. The optical laminate according to claim 1, wherein when the optical laminate is bent 180° so that the surface on which the antifouling 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.)

10. The optical laminate according to claim 9, 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.)

11. An article comprising an optical laminate according to any one of claims 1 to 10.

12. A method for manufacturing an optical laminate according to claim 1, A hard coat layer formation step involves forming a hard coat layer containing surface-modified silica filler on a transparent substrate, The process includes forming an adhesion layer on the hard coat layer, which consists of an adhesion layer made of a sputtered layer, A surface treatment step for treating the surface of the hard coat layer, An optical functional layer formation step is to form an optical functional layer on the aforementioned adhesion layer in which a high refractive index layer made of a sputtered film and a low refractive index layer with a refractive index lower than the high refractive index layer are alternately laminated. The process includes forming an antifouling layer on the optical functional layer, It has, A method for manufacturing an optical laminate, comprising the above surface treatment step, in which the surface of the hard coat layer is treated by glow discharge treatment to remove surface modifications of the silica filler surface exposed on the surface.

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