Optical laminate and article provided with same

Abstract

An optical laminate (102) has, in this order, a transparent substrate (11), a hard coat layer (12), an adhesion layer (13) comprising a sputtering film, an optical functional layer (14) obtained by alternately laminating a high-refractive-index layer comprising a sputtering film and a low-refractive-index layer having a lower refractive index than the high-refractive-index layer, and an antifouling layer (15). The hard coat layer 12 contains a silica filler, and the optical laminate satisfies the following conditions 1 and 2. Condition 1: The ratio ((A) / (B)) of the Martens hardness (A) on the antifouling layer side of the optical laminate and the Martens hardness (B) on the hard coat layer side of the laminate having only the transparent substrate and the hard coat layer is 3.6 or less. Condition 2: The difference in contact angle with water before friction and after friction by horizontally reciprocating the steel wool 200 times is 20 DEG or less using a friction tester using the steel wool in accordance with JIS L0849.

Description

Technical Field

[0001] The present invention relates to optical laminates and articles having the optical laminates, and more particularly to optical laminates used as anti-reflective films for displays suitable for use as flexible displays or other curved displays, and articles having the optical laminates.

[0002] This application claims priority based on Japanese Patent Application No. 2023-074698 filed on April 28, 2023, Japanese Patent Application No. 2024-063462 filed on April 10, 2024, and Japanese Patent Application No. 2024-069031 filed on April 22, 2024, the contents of which are incorporated herein by reference. Background Technology

[0003] In recent years, foldable displays have been sold in the market, appearing in portable communication terminals such as smartphones and information devices such as laptops. These displays sometimes use optical layers such as anti-reflective films to reduce surface reflection. Compared to non-foldable displays, foldable displays require greater durability against bending.

[0004] For example, in Patent Document 1, it is proposed that in a hard coating film having an optical functional layer consisting of a hard coating and a sputtered film, the bending resistance is improved by setting the thickness ratio of the hard coating to the optical functional layer within a specified range.

[0005] In addition, Patent Document 2 describes a method to improve bending resistance by making the hard coating and anti-reflective layer made of resin.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2022-185597

[0009] Patent Document 2: Japanese Patent Application Publication No. 2020-74019 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, in Patent Document 1, although the wear resistance and bending resistance of the hard coating were improved, the scratch resistance was not evaluated, leaving room for improvement.

[0012] In addition, although the bending resistance of the antireflective film can be improved in Patent Document 2, the antireflective layer is made of resin, so its scratch resistance is poor.

[0013] The present invention was made in view of the above-mentioned problems, and its object is to provide an optical laminate that can achieve excellent scratch resistance and further improve bending resistance, and an article having the optical laminate.

[0014] Methods for solving problems

[0015] To address the aforementioned issues, the present invention proposes the following solutions.

[0016] [1] An optical laminate, comprising, in sequence, a transparent substrate, a hard coating layer, an adhesive layer composed of sputtered films, an optical functional layer, and an antifouling layer, wherein the optical functional layer is formed by alternately stacking a high refractive index layer composed of sputtered films and a low refractive index layer with a refractive index lower than that of the high refractive index layer.

[0017] The aforementioned hard coating contains silica filler.

[0018] The aforementioned optical laminate satisfies the following conditions 1 and 2.

[0019] Condition 1: The ratio ((A) / (B)) of the martensitic hardness (A) of the optical laminate measured from the antifouling layer side to the martensitic hardness (B) of the laminate having only the transparent substrate and the hard coating layer measured from the hard coating layer side is 3.6 or less.

[0020] Condition 2: Using a friction tester based on JIS L0849 with steel wool, the difference in the contact angle with water before friction and after friction by making the steel wool reciprocate horizontally 200 times is less than 20°.

[0021] [2] According to the optical laminate described in [1] above, wherein the silica filler is surface-modified by functional groups from silane compounds.

[0022] [3] According to the optical laminate described in [2] above, wherein the silane compound is one or more selected from silane compounds containing vinyl groups, silane compounds containing (meth)acryloyl groups, silane compounds containing amino groups, silane compounds containing isocyanate groups, silane compounds containing isocyanurate groups, silane compounds containing epoxy groups, and silane compounds containing mercapto groups.

[0023] [4] According to the optical laminate described in [2] above, wherein the silane compound is a silane compound containing (meth)acryloyl groups.

[0024] [5] According to the optical laminate described in [2] above, wherein the hard coating contains an adhesive resin and a silica filler, and the functional group from the silane compound has the same functional group as the adhesive resin.

[0025] [6] According to the optical laminate described in [5] above, wherein the adhesive resin contains a (meth)acrylate compound and the functional group derived from the silane compound is a (meth)acryloyl group.

[0026] [7] According to the optical laminate described in [1] above, the average particle size of the silica filler is less than 800 nm.

[0027] [8] According to the optical laminate described in [1] above, the thickness of the hard coating is 0.5 μm or more and 100 μm or less.

[0028] [9] According to the optical laminate described in [1] above, when the optical laminate is bent 180° with the surface having the antifouling layer facing outward, the elongation S (%) of the optical functional layer calculated by the following formula (1) when using a mandrel with the smallest diameter that does not produce cracks satisfies 1.3 ≤ S.

[0029] S(%)={(R2 / R1)-1}×100···(1)

[0030] Wherein, R2 is the distance from the center of the aforementioned mandrel to the outer surface of the aforementioned optical laminate, and R1 is the distance from the center of the aforementioned mandrel to an imaginary line representing a position equivalent to 1 / 2 of the total thickness of the aforementioned optical laminate.

[0031]

[10] According to claim 9, when the optical laminate is bent 180° with the surface having the antifouling layer inside, the compression ratio C (%) of the optical functional layer calculated by the following formula (2) when using a mandrel with the smallest diameter that does not produce cracks satisfies 4.5 ≤ C.

[0032] C(%)={1-(R3 / R1)}×100···(2)

[0033] Wherein, R3 is the distance from the center of the aforementioned mandrel to the antifouling layer side surface of the aforementioned optical laminate, and R1 is the distance from the center of the aforementioned mandrel to an imaginary line representing a position equivalent to 1 / 2 of the total thickness of the aforementioned optical laminate.

[0034]

[11] An article having any one of the optical laminates described in any one of [1] to

[10] above.

[0035] Invention Effects

[0036] According to the present invention, it is possible to provide an optical laminate that achieves excellent scratch resistance and further improves bending resistance, and an article having the optical laminate. Attached Figure Description

[0037] [ Figure 1 [ ] is a cross-sectional view showing another example of the optical laminate of this embodiment.

[0038] [ Figure 2 [ ] is a cross-sectional view showing another example of the optical laminate of this embodiment.

[0039] [ Figure 3 [Illustrated diagram] is a schematic diagram of an example of a manufacturing apparatus that can be used in the manufacturing method of the optical laminate of this embodiment. Detailed Implementation

[0040] Hereinafter, this embodiment will be described in detail with appropriate reference to the accompanying drawings.

[0041] In the accompanying drawings used in the following description, for ease of understanding of the features of the invention, some parts that are to be considered features are sometimes shown in enlarged form, and the size ratios of the constituent elements may sometimes differ from the actual dimensions. The materials, dimensions, etc., illustrated in the following description are examples, and the invention is not limited thereto; it can be implemented with appropriate modifications within the scope of its effects.

[0042] [Optical laminate]

[0043] Figure 1 This is a cross-sectional view showing another example of the optical laminate of this embodiment.

[0044] Figure 1 The optical laminate 102 shown is formed by sequentially stacking a transparent substrate 11, a hard coating layer 12, an adhesive layer 13, an optical functional layer 14, and an antifouling layer 15.

[0045] The sealing layer 13 is the layer that enables the sealing between the hard coating layer 12 and the optical functional layer 14.

[0046] Optical functional layer 14 is the layer that expresses optical functions. Optical functions are the functions that control the reflection, transmission, and refraction of light as properties, such as anti-reflection functions, selective reflection functions, and lens functions.

[0047] The optical functional layer 14 preferably includes any one selected from an anti-reflective layer and a selective reflective layer. Known anti-reflective layers and selective reflective layers can be used as the anti-reflective layer and selective reflective layer. Both the anti-reflective layer and the selective reflective layer can be single layers or multi-layered stacks.

[0048] Figure 2 This is a cross-sectional view showing another example of the optical laminate of this embodiment.

[0049] Figure 2 In the optical laminate 101 shown, as Figure 1The optical functional layer 14 in the optical laminate 102 shown has an anti-reflective layer. For example... Figure 1 As shown, the optical functional layer 14 (anti-reflective layer) is composed of a stack of alternating layers of low refractive index layer 14b and high refractive index layer 14a. Figure 1 The optical functional layer 14 shown comprises, in sequence from the transparent substrate 11 side, a hard coating layer 12, an adhesive layer 13, a high refractive index layer 14a, a low refractive index layer 14b, another high refractive index layer 14a, a low refractive index layer 14b, and an 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.

[0050] The transparent substrate 11 can be formed of a transparent material that can transmit light in the visible light region. For example, a plastic film is preferably used as the transparent substrate 11. Specific examples of materials constituting 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.

[0051] It should be noted that the "transparent material" mentioned in this invention refers to a material with a light transmittance of 80% or more in the wavelength range used, without impairing the effect of this invention.

[0052] In addition, in this embodiment, "(meth)acrylic acid" refers to methacrylic acid and acrylic acid.

[0053] The transparent substrate 11 may also include a reinforcing material, provided that the optical properties are not significantly impaired. Examples of reinforcing materials include cellulose nanofibers and nano-silica. Polyester-based resins, acetate-based resins, polycarbonate-based resins, and polyolefin-based resins are particularly preferred as reinforcing materials. Specifically, triacetyl cellulose (TAC) substrates are preferred as reinforcing materials.

[0054] Alternatively, the transparent substrate 11 can also be a glass film, which is an inorganic substrate.

[0055] If the plastic film is a TAC substrate, when the hard coating 12 is formed on one side, a permeation layer is formed by the permeation of a portion of the components constituting the hard coating 12. As a result, the adhesion between the transparent substrate 11 and the hard coating 12 becomes good, and the generation of interference fringes caused by the refractive index difference between the layers can be suppressed.

[0056] The transparent substrate 11 can be a film that imparts optical and / or physical functions. Examples of films with optical and / or physical functions include polarizers, phase difference compensation films, heat ray blocking films, transparent conductive films, brightness enhancement films, and barrier properties improving films.

[0057] 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.

[0058] When the thickness of the transparent substrate 11 is 25 μm or more, the rigidity of the substrate itself is ensured, and wrinkles are less likely to occur even when stress is applied to the optical laminate 10. Furthermore, if the thickness of the transparent substrate 11 is 25 μm or more, wrinkles are less likely to occur even when the hard coating 12 is continuously formed on the transparent substrate 11, reducing manufacturing concerns and making this preferable. If the thickness of the transparent substrate 11 is 40 μm or more, wrinkles are even less likely to occur, making this preferable as well.

[0059] During manufacturing, when using rollers, the thickness of the transparent substrate 11 is preferably 1000 μm or less, more preferably 600 μm or less. When the thickness of the transparent substrate 11 is 1000 μm or less, it is easy to wind the optical laminate 10 during manufacturing and the manufactured optical laminate 10 into a roll, enabling efficient manufacturing of the optical laminate 10. Furthermore, if the thickness of the transparent substrate 11 is 1000 μm or less, it is possible to achieve thinner and lighter optical laminate 10. If the thickness of the transparent substrate 11 is 600 μm or less, it is preferable to manufacture the optical laminate 10 more efficiently and further achieve thinner and lighter weight.

[0060] The transparent substrate 11 may undergo pre-treatment of its surface by sputtering, corona discharge, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, or other etching processes and / or primer treatment. By performing these pre-treatments, the adhesion to the hard coating 12 formed on the transparent substrate 11 can be improved. Furthermore, it is preferable to perform solvent cleaning, ultrasonic cleaning, or other methods on the surface of the transparent substrate 11 as needed before forming the hard coating 12, thereby removing dust and cleaning the surface of the transparent substrate 11.

[0061] The hard coating 12 uses adhesive resin and fillers as essential components, and may contain other components such as dispersants as optional components. The adhesive resin can be a known substance. The filler is included in the adhesive resin to the extent that it does not impair transparency.

[0062] As fillers, fillers composed of organic materials, inorganic materials, or a combination of both can be used. From the viewpoint of hardness and flexural strength, fillers composed of inorganic materials are preferred, and silica particles composed of silica are even more preferred. In addition, silica particles that have undergone surface modification are particularly preferred.

[0063] The adhesive resin used in the hard coating 12 is preferably a transparent adhesive resin, such as an ionizing radiation-curable resin, thermoplastic resin, thermosetting resin, etc., which are resins that are cured by ultraviolet light or electron beam.

[0064] Examples of ionizing radiation-curing resins used as adhesive resins in the hard coating 12 include ethyl methacrylate, ethylhexyl methacrylate, styrene, methylstyrene, and N-vinylpyrrolidone.

[0065] In addition, 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, di(trimethylolpropane)tetra(meth)acrylate, and di... Multifunctional compounds such as pentaerythritol penta(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, isocyanurate tri(meth)acrylate, isocyanurate di(meth)acrylate, polyester tri(meth)acrylate, polyester di(meth)acrylate, bisphenol di(meth)acrylate, diglycerol tetra(meth)acrylate, adamantyl di(meth)acrylate, isobornyl di(meth)acrylate, dicyclopentane di(meth)acrylate, tricyclodecane di(meth)acrylate, and di(trimethylolpropane)tetra(meth)acrylate are used. Among them, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), and pentaerythritol tetraacrylate (PETTA) are preferred. It should be noted that "(meth)acrylate" refers to methacrylates and acrylates. Alternatively, as an ionizing radiation-curing resin, a resin modified with PO (propylene oxide), EO (ethylene oxide), CL (caprolactone), etc., can also be used. Furthermore, from the viewpoint of film formation and viscoelasticity adjustment of the hard coating, urethane (meth)acrylate oligomers, epoxy (meth)acrylate oligomers, etc., can also be used.

[0066] Thermoplastic resins used as adhesive resins for the hard coating 12 include, for example, styrene-based resins, (meth)acrylic resins, vinyl acetate resins, vinyl ether resins, halogenated resins, alicyclic olefin resins, polycarbonate resins, polyester resins, polyamide resins, cellulose derivatives, silicone resins, and rubbers or elastomers. These thermoplastic resins are preferably non-crystalline and soluble in organic solvents (especially general solvents capable of dissolving various polymers and curing compounds). From the viewpoint of transparency and weather resistance, styrene-based resins, (meth)acrylic resins, alicyclic olefin resins, polyester resins, and cellulose derivatives (cellulose esters, etc.) are particularly preferred.

[0067] The hard coating 12 comprises, for example, an adhesive resin and silica particles as fillers. Preferably, the silica particles are pre-surface-modified silica particles.

[0068] Specific examples of silane compounds include vinyl silane compounds, (meth)acryloyl silane compounds, amino silane compounds, isocyanate silane compounds, isocyanurate silane compounds, epoxy silane compounds, and mercapto silane compounds. One or more of these compounds may be used. The silane compound is appropriately selected based on the type of adhesive resin, but when the adhesive resin contains functional groups, a silane compound having the same functional groups as the adhesive resin is preferred. For example, when the adhesive resin contains a (meth)acrylate compound as an ionizing radiation-curing resin, the silane compound is preferably an alkoxysilane compound containing a (meth)acryloyl group. It should be noted that "(meth)acrylate" refers to methacrylate and / or acrylate. Furthermore, in this invention, from the perspective of the reaction mechanism, methacrylate and acrylate are treated as the same substance. Since the silane compound used for surface modification bonds well with the hydroxyl groups present on the surface of silica particles, it is preferable to have alkoxysilyl or silanol groups at the terminal.

[0069] By pre-modifying the surface of silica particles, the adhesive resin is more firmly bonded to the adhesive resin through improved dispersibility in the adhesive resin and the reaction between the surface treatment agent used in the surface modification and the adhesive resin, thereby increasing the hardness of the optical laminate.

[0070] These silica particles can be exposed on the surface of the hard coating 12 on the side of the optical functional layer 14. In this case, the hard coating 12 and the optical functional layer 14 are more strongly bonded via the bonding layer 13. Exposure methods include glow discharge treatment, which is described later, in which case the surface modifications on the exposed silica surface are removed.

[0071] By exposing the filler on the hard coating surface and removing the surface modification, electrostatic attraction is generated between the hydroxyl groups on the filler surface and the adhesive layer 13 (described later), further improving the adhesion. Additionally, the exposed filler acting as an anchor that bites into the adhesive layer 13 also contributes to improved adhesion. The improved flexural strength results from the combination of the surface modification of the silica surface, the bonding with the adhesive resin, and the interaction between the silica and the adhesive layer.

[0072] The average particle size of the filler in the hard coating 12 is, for example, 800 nm or less, preferably 780 nm or less, and more preferably 100 nm or less. If the particle size of the filler is within this range, the overall haze value of the optical laminate 10 is 2% or less. The optical laminate 10 with a haze of 2% or less has high transparency and is thus considered a transparent antireflective film.

[0073] The hard coating 12 is preferably subjected to surface treatments such as glow discharge treatment, plasma treatment, ion etching, or alkaline treatment. Glow discharge treatment is preferred because it allows for large-area processing. The intensity of the glow discharge treatment, for example as the electrode power density, can be as high as 100 W / m². 2 ~ 11000W / m 2 The preferred setting is 1600W / m. 2 ~7000W / m 2 conduct.

[0074] By performing glow discharge treatment on the surface of the hard coating 12, the surface of the hard coating 12 is roughened at the nanoscale, and weakly bonded substances present on the surface of the hard coating 12 are removed. As a result, the adhesion between the hard coating 12 and the adhesive layer 13 formed on the hard coating 12 becomes good. In addition, it also has the effect of exposing silica particles from the hard coating 12. Furthermore, if the intensity of the discharge treatment is increased, there is a tendency for improved flexural strength, which will be described later. However, if a certain or higher discharge intensity is reached, the effect reaches its peak. Moreover, excessive glow discharge intensity can lead to the deterioration of the resin constituting the hard coating. Therefore, it is preferable to perform glow discharge treatment with a discharge intensity within the above-mentioned range.

[0075] It should be noted that, when an anti-glare optical laminate is desired, the average particle size of the filler in the hard coating 12 can be, for example, 0.5 μm or more. Organic microparticles such as acrylic resin are suitable as fillers of this size. If the filler particle size is within this range, the overall haze value of the optical laminate 10 exceeds 2%. An optical laminate 10 with a haze exceeding 2% exhibits anti-glare properties and becomes a so-called anti-glare (AG) type anti-reflective film. In this case, the average particle size of the filler is preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less.

[0076] As fillers contained in the hard coating 12, various reinforcing materials can be used within a range that does not impair optical properties in order to impart high toughness to the hard coating 12. Examples of reinforcing materials include cellulose nanofibers.

[0077] The thickness of the hard coating 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 coating 12 is preferably 100 μm or less. When the thickness of the hard coating 12 is 0.5 μm or more, sufficient hardness can be obtained, thus reducing the likelihood of manufacturing scratches. Furthermore, when the thickness of the hard coating 12 is 100 μm or less, thinner and lighter optical laminates 10 can be achieved. Additionally, when the thickness of the hard coating 12 is 100 μm or less, microcracks in the hard coating 12 that occur during bending of the optical laminate 10 during manufacturing are less likely to occur, resulting in better productivity.

[0078] The hard coating 12 can be a single layer or a layer with multiple layers stacked on top of each other. In addition, the hard coating 12 can be further endowed with known functions such as ultraviolet absorption properties, antistatic properties, refractive index adjustment functions, and hardness adjustment functions.

[0079] In addition, the function of applying the hard coating 12 can be applied to a single hard coating or applied to multiple layers in a segmented manner.

[0080] The bonding layer 13 is formed to ensure good adhesion between the transparent substrate 11 (an organic film) or the hard coating layer 12 and the optical functional layer 14 (an inorganic film). Figure 2 In the optical laminate 10 shown, an adhesive layer 13 is provided between the hard coating layer 12 and the optical functional layer 14. The adhesive layer 13 functions to seal the hard coating layer 12 and the optical functional layer 14. The adhesive layer 13 is preferably composed of an oxygen-deficient metal oxide or a metal. An oxygen-deficient metal oxide refers to a metal oxide in which the number of oxygens is insufficient compared to its 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 adhesive layer 13 can be, for example, a layer in SiOx where x is greater than 0 and less than 2.0. Alternatively, the adhesive layer can also be formed from a mixture of various metals or metal oxides.

[0081] From the viewpoint of maintaining transparency and tightness with the optical functional layer and obtaining good optical properties, the thickness of the sealing layer is preferably greater than 0 nm and less than 20 nm, and particularly preferably greater than 1 nm and less than 10 nm.

[0082] The optical functional layer 14 is a laminate that performs anti-reflective functions. Figure 2 The optical functional layer 14 shown is a stack of four layers consisting of alternating high-refractive-index layers 14a and low-refractive-index layers 14b, starting from the sealing layer 13 side. The number of high-refractive-index layers 14a and low-refractive-index layers 14b is not particularly limited and can be set to any number.

[0083] exist Figure 2 In the optical laminate 10 shown, the optical functional layer 14 is composed of a laminate with alternating layers of low-refractive-index layer 14b and high-refractive-index layer 14a. Therefore, light incident from the anti-fouling layer 15 side is interfered with by the optical functional layer 14, thereby reducing the intensity of reflected light and achieving an anti-reflection function. Thus, an anti-reflection function that prevents light incident from the anti-fouling layer 15 side from being reflected in one direction can be obtained.

[0084] The low refractive index layer 14b may contain, for example, a metal oxide. From the viewpoint of ease of acquisition and cost, the low refractive index layer 14b may contain an oxide of Si, preferably a layer with SiO2 (an oxide of Si) as the main component. The SiO2 monolayer film is colorless and transparent. In this embodiment, the main component of the low refractive index layer 14b refers to a component containing 50% by mass or more in the low refractive index layer 14b.

[0085] In the case where the low refractive index layer 14b is a layer mainly composed of Si oxide, it may also contain less than 50% by mass of other elements. The content of elements different from Si oxide is preferably 10% or less. As other elements, Na may be included for the purpose of improving durability, Zr, Al or N may be included for the purpose of improving hardness, and Zr or Al may be included for the purpose of improving alkali resistance.

[0086] The refractive index of the low refractive index layer 14b is preferably 1.20 to 1.60, more preferably 1.30 to 1.50. Examples of dielectrics used in the low refractive index layer 14b include magnesium fluoride (MgF2, refractive index 1.38).

[0087] The refractive index of the high refractive index layer 14a is preferably 2.00 to 2.60, more preferably 2.10 to 2.45. Examples of 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).

[0088] If it is desired to impart conductive properties to the high refractive index layer 14a, for example, ITO, indium oxide, or zinc oxide (IZO) can be selected.

[0089] The optical functional layer 14 preferably uses a layer made of niobium pentoxide (Nb2O5, refractive index 2.33) as a high refractive index layer 14a, and a layer made of SiO2 as a low refractive index layer 14b.

[0090] The thickness of the low refractive index layer 14b only needs to be in the range of 1 nm or more and 200 nm or less, and can be appropriately selected according to the wavelength range required for anti-reflection function.

[0091] The thickness of the high refractive index layer 14a can be, for example, greater than 1 nm and less than 200 nm, and can be appropriately selected according to the wavelength range required for the anti-reflection function.

[0092] 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.

[0093] For example, starting from the sealing layer 13 side, there can be a high refractive index layer 14a of 5~50nm, a low refractive index layer 14b of 10~80nm, a high refractive index layer 14a of 20~200nm, and a low refractive index layer 14b of 50~200nm.

[0094] A low-refractive-index layer 14b is disposed on the side of the anti-fouling layer 15 in the layer forming the optical functional layer 14. When the low-refractive-index layer 14b of the optical functional layer 14 is in contact with the anti-fouling layer 15, the anti-reflective performance of the optical functional layer 14 becomes good, which is therefore preferred.

[0095] An anti-fouling layer 15 is formed on the outermost surface of the optical functional layer 14 to prevent contamination of the optical functional layer 14. In addition, when the anti-fouling layer 15 is applied to touch panels or the like, it suppresses wear and tear on the optical functional layer 14 through its abrasion resistance.

[0096] In this embodiment, the antifouling layer 15 is composed of a vapor-deposited film containing an antifouling material. In this embodiment, the antifouling layer 15 is formed on one side of the low-refractive-index layer 14b constituting the optical functional layer 14 by vacuum vapor deposition of a fluorine-based organic compound as the antifouling material. In this embodiment, the antifouling material contains a fluorine-based organic compound, thus resulting in an optical laminate 10 with better abrasion resistance and alkali resistance.

[0097] As the fluorinated organic compound constituting the antifouling layer 15, a compound consisting of fluorinated modified organic groups and reactive silyl groups (e.g., alkoxysilanes) is preferably used. Examples of commercially available products include OPTOOL DSX (manufactured by Daikin Industries, Ltd.) and the KY-100 series (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0098] When a fluorinated organic compound constituting the antifouling layer 15 is used, consisting of fluorinated modified organic groups and reactive silyl groups (e.g., alkoxysilanes), and a low-refractive-index layer 14b of the optical functional layer 14 in contact with the antifouling layer 15 is made of SiO2, siloxane bonds are formed between the silanol groups that form the backbone of the fluorinated organic compound and the SiO2. Therefore, good adhesion between the optical functional layer 14 and the antifouling layer 15 is preferred.

[0099] The optical thickness of the anti-fouling layer 15 can 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 anti-fouling layer 15 is 1 nm or more, sufficient wear resistance can be ensured when the optical laminate 10 is applied to touch panels, etc. In addition, if the thickness of the anti-fouling layer 15 is 3 nm or more, the liquid resistance of the optical laminate 10 is improved. In addition, if the thickness of the anti-fouling layer 15 is 20 nm or less, the time required for vapor deposition can be shortened, enabling efficient manufacturing.

[0100] In the optical laminates 10 and 102 configured as described above, the ratio ((A) / (B)) of the martensitic hardness (A) measured from the antifouling layer 15 side of the optical laminates 10 and 102 to the martensitic hardness measured from the hard coating 12 side of the laminate having only the transparent substrate 11 and the hard coating 12 is 3.6 or less (condition 1). Furthermore, the ratio ((A) / (B)) is preferably 3.5 or less, more preferably 3.4 or less. When the ratio ((A) / (B)) is 3.6 or less, the hardness difference between the hard coating surface and the antifouling layer surface becomes smaller, thereby suppressing deformation. As a result, excellent scratch resistance can be achieved, and bending resistance can be further improved.

[0101] Furthermore, in the optical laminates 10 and 102 constructed as described above, using a friction testing machine with steel wool according to JIS L0849, the difference in contact angle with water before friction and after friction by making the steel wool reciprocate horizontally 200 times is 20° or less (condition 2). When the hardness of the optical laminates 10 and 102 is high, the above-mentioned contact angle difference becomes 20° or less, which can achieve excellent scratch resistance.

[0102] In the optical laminates 10 and 102 configured as described above, when the optical laminates 10 and 102 are bent 180° with the surface having the anti-fouling layer 15 facing outwards, the elongation S (%) of the optical functional layer 14, calculated by the following formula (1) when using a mandrel with the smallest diameter that does not produce cracks, preferably satisfies 1.3 ≤ S. This further improves the bending resistance of the optical laminates 10 and 102.

[0103] S={(R2 / R1)-1}×100···(1)

[0104] (Where R2 is the distance from the center of the aforementioned mandrel to the outer surface of the aforementioned optical laminate, and R1 is the distance from the center of the aforementioned mandrel to an imaginary line representing a position equivalent to 1 / 2 of the total thickness of the aforementioned optical laminate).

[0105] Furthermore, in the optical laminates 10 and 102, when the optical laminates 10 and 102 are bent 180° with the surface having the anti-fouling layer 15 forming the inside, the compression ratio C (%) of the optical functional layer 14 calculated by the following formula (2) when using a mandrel with the smallest diameter that does not produce cracks preferably satisfies 4.5 ≤ C, and more preferably satisfies 5 ≤ ​​C. This further improves the bending resistance of the optical laminates 10 and 102.

[0106] C(%)={1-(R3 / R1)}×100···(2)

[0107] (Where R3 is the distance from the center of the aforementioned mandrel to the antifouling layer side surface of the aforementioned optical laminate, and R1 is the distance from the center of the aforementioned mandrel to an imaginary line representing a position equivalent to 1 / 2 of the total thickness of the aforementioned optical laminate).

[0108] Furthermore, the optical functional layer 14 preferably satisfies both the aforementioned range of elongation S (%) and compression ratio C (%). That is, in the optical laminates 10 and 102, when the optical laminates 10 and 102 are bent 180° with the surface having the anti-fouling layer 15 facing outwards, the elongation S (%) of the optical functional layer 14 calculated by the following formula (1) using a mandrel with the smallest diameter that does not produce cracks satisfies 1.3 ≤ S, and when the optical laminates 10 and 102 are bent 180° with the surface having the anti-fouling layer 15 facing inwards, the compression ratio C (%) of the optical functional layer 14 calculated by the above formula (2) using a mandrel with the smallest diameter that does not produce cracks preferably satisfies 4.5 ≤ C. As a result, the bending resistance of the optical laminates 10 and 102 can be further improved.

[0109] It should be noted that the above elongation is the value when the substrate is PET and the thickness is 50μm. If the thickness is reduced, the value may change.

[0110] In the optical laminates 10 and 102 configured as described above, when the thickness of the hard coating of the optical laminate is 5 μm, when the optical laminates 10 and 102 are bent 180° with the surface having the antifouling layer 15 facing outward, the mandrel diameter is gradually replaced with a smaller mandrel diameter. The diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is preferably 4.0 φ mm or less, more preferably 3.5 φ mm or less, and even more preferably 3.0 φ mm or less.

[0111] Furthermore, when the thickness of the hard coating of the optical laminate is 5 μm, when the optical laminates 10 and 102 are bent 180° with the surface where the antifouling layer 15 is formed facing inward, the mandrel diameter is gradually replaced with a smaller mandrel diameter. The diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is preferably 1.1 φ mm or less, and more preferably less than 1.0 φ mm.

[0112] Furthermore, when the thickness of the hard coating of the optical laminate is 5 μm, it is more preferable that when the optical laminates 10 and 102 are bent 180° with the surface having the antifouling layer 15 on the outside, the mandrel diameter is gradually replaced with a smaller mandrel diameter, such that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is 4.0 φ mm or less. Also, when the optical laminates 10 and 102 are bent 180° with the surface having the antifouling layer 15 on the inside, the mandrel diameter is gradually replaced with a smaller mandrel diameter, such that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is 1.1 φ mm or less.

[0113] In the optical laminates 10 and 102 configured as described above, when the thickness of the hard coating of the optical laminate is 10 μm, when the optical laminates 10 and 102 are bent 180° with the surface having the antifouling layer 15 facing outward, the mandrel diameter is gradually replaced with a smaller mandrel diameter. The diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is preferably 4.0 φ mm or less, more preferably 3.5 φ mm or less, and even more preferably 3.0 φ mm or less.

[0114] Furthermore, when the thickness of the hard coating of the optical laminate is 10 μm, when the optical laminates 10 and 102 are bent 180° with the surface where the antifouling layer 15 is formed facing inward, the mandrel diameter is gradually replaced with a smaller mandrel diameter. The diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is preferably 1.4 φ mm or less, and more preferably 1.2 φ mm or less.

[0115] Furthermore, when the thickness of the hard coating of the optical laminate is 10 μm, it is more preferable that when the optical laminates 10 and 102 are bent 180° with the surface having the antifouling layer 15 on the outside, the mandrel diameter is gradually replaced with a smaller mandrel diameter, such that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is 4.0 φ mm or less. Also, when the optical laminates 10 and 102 are bent 180° with the surface having the antifouling layer 15 on the inside, the mandrel diameter is gradually replaced with a smaller mandrel diameter, such that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is 1.4 φ mm or less.

[0116] In the optical laminates 10 and 102 configured as described above, when the thickness of the hard coating of the optical laminate is 2 μm, when the optical laminates 10 and 102 are bent 180° with the surface having the antifouling layer 15 facing outward, the mandrel diameter is gradually replaced with a smaller mandrel diameter. The diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is preferably 4.0 φ mm or less, more preferably 3.5 φ mm or less, and even more preferably 3.0 φ mm or less.

[0117] Furthermore, when the thickness of the hard coating of the optical laminate is 2 μm, when the optical laminates 10 and 102 are bent 180° with the surface where the antifouling layer 15 is formed facing inward, the mandrel diameter is gradually replaced with a smaller mandrel diameter. The diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is preferably 1.1 φ mm or less, and more preferably less than 1.0 φ mm.

[0118] Furthermore, when the thickness of the hard coating of the optical laminate is 2 μm, it is more preferable that when the optical laminates 10 and 102 are bent 180° with the surface having the antifouling layer 15 on the outside, the mandrel diameter is gradually replaced with a smaller mandrel diameter, such that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is 4.0 φ mm or less. Also, when the optical laminates 10 and 102 are bent 180° with the surface having the antifouling layer 15 on the inside, the mandrel diameter is gradually replaced with a smaller mandrel diameter, such that the diameter of the mandrel that is 0.2 mm larger than the diameter of the mandrel where the crack was first discovered is 1.1 φ mm or less.

[0119] It should be noted that the above mandrel diameter was measured by cutting three pieces of the same sample and calculated from the average of the three measurements.

[0120] [Manufacturing method of optical laminates]

[0121] Figure 2 The optical laminate 10 of this embodiment shown can be manufactured, for example, by the method shown below.

[0122] In this embodiment, as an example of the manufacturing method of the optical laminate 10, the case of manufacturing the optical laminate 10 using a transparent substrate 11 wound into a roll will be described.

[0123] First, a transparent substrate 11 wound into a roll is unwound. Then, a slurry containing a material that forms a hard coating 12 is applied to the transparent substrate 11 using a known method, and cured using a known method corresponding to the material forming the hard coating 12. For example, a composition containing an adhesive resin and silica particles as filler can be used as the slurry. This composition is applied to the transparent substrate 11 and then cured. Thus, a hard coating 12 is formed on the transparent substrate 11 (hard coating formation step). The composition may contain one or more additives such as a polymerization initiator and a leveling agent, as needed. For example, a photopolymerization initiator is used as the polymerization initiator. Then, the transparent substrate 11 with the hard coating 12 formed on its surface is wound into a roll using a known method.

[0124] Next, an adhesive layer forming process is performed to form an adhesive layer 13 on the hard coating 12, and an optical functional layer forming process is performed to form an optical functional layer 14. Then, an antifouling layer forming process 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 process to treat the surface of the hard coating 12 before the optical functional layer forming process, and then perform the adhesive layer forming process and the optical functional layer forming process. Alternatively, in this embodiment, it is preferable to perform a second surface treatment process to treat the surface of the optical functional layer 14 after the optical functional layer forming process, and then perform the antifouling layer forming process.

[0125] In the manufacturing method of the optical laminate 10 of this embodiment, it is preferable that the first surface treatment step, the adhesive layer formation 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. When the first surface treatment step, the adhesive layer formation 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, for example, an apparatus equipped with a thin film forming apparatus as described in Patent Document 4 can be used as the sputtering apparatus.

[0126] Specifically, examples of manufacturing apparatus that can be used in the manufacturing method of the optical laminate of this embodiment include: Figure 3 The manufacturing apparatus 20 shown.

[0127] Figure 3The manufacturing apparatus 20 shown includes 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. For example... Figure 3 As shown, these devices 4, 2A, 1, 2B, 3, and 5 are connected in sequence. Figure 3 The manufacturing apparatus 20 shown is a roll-to-roll manufacturing apparatus, in which the substrate is unwound from the roll and continuously passed through a connecting device (in... Figure 3 After the pretreatment device 2A, sputtering device 1, pretreatment device 2B, and vapor deposition device 3 are connected, they are wound to continuously form multiple layers on the substrate.

[0128] When manufacturing the optical laminate 10 using a roll-to-roll manufacturing apparatus, the conveying speed (linear speed) of the optical laminate 10 during manufacturing can be appropriately set. The conveying speed is preferably 0.5 to 20 m / min, and more preferably 0.5 to 10 m / min.

[0129] <Roller Unwinding Device>

[0130] Figure 3 The roller unwinding device 4 shown has a chamber 34 with a predetermined reduced pressure atmosphere inside, and one or more vacuum pumps 21 that discharge the gas in the chamber 34 to form a reduced pressure atmosphere. Figure 3 (One of them) and the unwinding roller 23 and guide roller 22 disposed in the chamber 34. Figure 3 As shown, chamber 34 is connected to chamber 31 of sputtering device 1 via pretreatment device 2A.

[0131] A transparent substrate 11 with a hard coating 12 formed on its surface is wound on the unwinding roller 23. The unwinding roller 23 supplies the transparent substrate 11 with the hard coating 12 formed on its surface to the forward processing device 2A at a predetermined conveying speed.

[0132] <Pre-processing unit 2A>

[0133] Figure 3 The pretreatment apparatus 2A shown has a chamber 32 with a prescribed reduced pressure atmosphere inside, rollers 26, and multiple (in) Figure 3 The middle section contains two guide rollers 22 and a plasma discharge device 42. (For example...) Figure 3 As shown, the roller 26, guide roller 22, and plasma discharge device 42 are disposed within the chamber 32. Figure 3 As shown, chamber 32 is connected to chamber 31 of sputtering device 1.

[0134] The roller 26 and guide roller 22 convey the transparent substrate 11 with a hard coating 12 from the unwinding device 4 at a specified conveying speed, and the transparent substrate 11 with the hard coating 12 surface treated is sent to the sputtering device 1.

[0135] like Figure 3 As shown, the plasma discharge device 42 and the outer peripheral surface of the roller 26 are arranged opposite each other at a predetermined interval. The plasma discharge device 42 ionizes the gas through glow discharge. As the gas, a low-valence, inactive gas that does not affect optical properties is preferred, such as argon, oxygen, nitrogen, helium, etc. In this embodiment, argon or oxygen is preferably used as the gas.

[0136] Sputtering device

[0137] Figure 3 The sputtering apparatus 1 shown has a chamber 31 with a predetermined reduced pressure atmosphere inside, and one or more vacuum pumps 21 that exhaust the gas in the chamber 31 to form a reduced pressure atmosphere. Figure 3 Two in the middle), film forming roller 25, multiple (two in Figure 4) guide rollers 22, multiple (in Figure 4) Figure 3 The example shown has four film-forming sections 41. Figure 3 As shown, the film-forming roller 25, guide roller 22, and film-forming section 41 are disposed within the chamber 31. Figure 3 As shown, chamber 31 is connected to chamber 32 of pretreatment device 2B.

[0138] The film-forming roller 25 and the guide roller 22 convey the transparent substrate 11, which has a surface-treated hard coating 12, from the pretreatment device 2A at a specified conveying speed, and supply the transparent substrate 11, on which an adhesive layer 13 and an optical functional layer 14 are formed, to the pretreatment device 2B.

[0139] exist Figure 3 In the sputtering apparatus 1 shown, an adhesive layer 13 is deposited by sputtering on the hard coating layer 12 of a transparent substrate 11 traveling on a film-forming roller 25, and a high refractive index layer 14a and a low refractive index layer 14b are alternately deposited thereon to form an optical functional layer 14.

[0140] like Figure 3As shown, the film-forming sections 41 and the outer peripheral surfaces of the film-forming rollers 25 are arranged opposite each other at predetermined intervals, and multiple sections are provided to surround the film-forming rollers 25. The number of film-forming sections 41 is determined by the total number of layers of the adhesive layer 13 and the high-refractive-index layer 14a and low-refractive-index layer 14b to form the optical functional layer 14. When it is difficult to ensure the distance between adjacent film-forming sections 41 due to the large total number of layers of the adhesive layer 13 and the high-refractive-index layer 14a and low-refractive-index layer 14b to form the optical functional layer 14, multiple film-forming rollers 25 can be provided in the chamber 31, and film-forming sections 41 can be arranged around each film-forming roller 25. When multiple film-forming rollers 25 are provided, guide rollers 22 can be further provided as needed. Multiple chambers 31 with film-forming rollers 25 and film-forming sections 41 can also be connected together. Furthermore, the diameter of the film-forming rollers 25 can be appropriately changed to easily ensure the distance between adjacent film-forming sections 41.

[0141] Each film-forming section 41 is provided with a predetermined target (not shown). A voltage is applied to the target using a known structure. In this embodiment, a gas supply section (not shown) that supplies a predetermined reactive gas and a carrier gas to the target at a predetermined flow rate, and a known magnetic field generating source (not shown) that forms a magnetic field on the surface of the target are provided near the target.

[0142] The target material and the type and flow rate of the reactive gas are appropriately determined based on the composition of the bonding layer 13, the high refractive index layer 14a, and the low refractive index layer 14b to be formed on the transparent substrate 11 between the film-forming section 41 and the film-forming roller 25. For example, in the case of forming a layer composed of SiO2, Si is used as the target and O2 is used as the reactive gas. Alternatively, for example, in the case of forming a layer composed 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 with a vacuum degree of less than 0.5 Pa, and the high refractive index layer 14a is preferably formed with a vacuum degree of less than 1.0 Pa. If these layers are formed with this vacuum degree, the optical functional layer 14 becomes dense, the water vapor transmittance is reduced, and the durability is improved.

[0143] In this embodiment, from the viewpoint of increasing the film formation speed, magnetron sputtering is preferred as the sputtering method.

[0144] In addition, sputtering methods are not limited to magnetron sputtering; two-electrode sputtering methods that utilize plasma generated by DC glow discharge or high frequency, and three-electrode sputtering methods with an additional hot cathode can also be used.

[0145] The sputtering apparatus 1 includes an optical monitor (not shown) as a measurement unit. This optical monitor measures the optical properties after each layer, which will become the sealing layer 13 and the optical functional layer 14, is formed. This allows for confirmation of the quality of the formed sealing layer 13 and optical functional layer 14. For example, if the sputtering apparatus 1 has two or more chambers, it is preferable to install an optical monitor in each chamber.

[0146] As an optical monitor (not shown), an example is an optical monitor that measures the optical properties of the bonding layer 13 and the optical functional layer 14 formed on the hard coating 12 in the width direction using an optical head capable of scanning in the width direction. With such an optical monitor, for example, by measuring the peak wavelength of reflectivity as an optical property and converting it into optical thickness, the optical thickness distribution of the bonding layer 13 and the optical functional layer 14 in the width direction can be measured. By measuring the optical properties using an optical monitor, an optical laminate 10 having an bonding layer 13 and an optical functional layer 14 with optimal optical properties can be formed while adjusting the sputtering conditions in real time.

[0147] <Pre-processing unit 2B>

[0148] Figure 3 The pretreatment device 2B shown has a chamber 32 with a prescribed reduced pressure atmosphere inside, rollers 26, and multiple (in) Figure 3 The middle section contains two guide rollers 22 and a plasma discharge device 42. (For example...) Figure 3 As shown, the roller 26, guide roller 22, and plasma discharge device 42 are disposed within the chamber 32. Figure 3 As shown, chamber 32 is connected to chamber 33 of vapor deposition apparatus 3.

[0149] The roller 26 and guide roller 22 convey the transparent substrate 11, which is formed with each layer up to the optical functional layer 14, from the sputtering device 1 at a specified conveying speed, and deliver the transparent substrate 11 with the surface treated of the optical functional layer 14 to the vapor deposition device 3.

[0150] As a plasma discharge device 42, for example, the same device as the pretreatment device 2A can be used.

[0151] <Evaporation Equipment>

[0152] The vapor deposition apparatus 3 shown in Figure 4 has a chamber 33 with a predetermined reduced pressure atmosphere inside, and one or more vacuum pumps 21 that discharge the gas in the chamber 33 to form a reduced pressure atmosphere. Figure 3 (1 in the middle) (multiple in the middle) Figure 3 The system consists of four components: guide rollers 22, vapor deposition source 43, and heating device 53. Figure 3 As shown, the guide roller 22 and the vapor deposition source 43 are disposed in the chamber 33. The chamber 33 is connected to the chamber 35 of the roller winding device 5.

[0153] The vapor deposition source 43 is positioned opposite a transparent substrate 11, whose surface has been treated, and which is conveyed substantially horizontally between two adjacent guide rollers 22. The vapor deposition source 43 supplies evaporated gas, which is composed of a material that forms an anti-fouling layer 15, to the optical functional layer 14. The orientation of the vapor deposition source 43 can be set arbitrarily.

[0154] 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 any heating device that uses resistance heating, heater heating, induction heating, or electron beam heating. In resistance heating, the container holding the antifouling material that will become the antifouling layer 15 is heated by passing electricity through it. In heater heating, the container is heated using a heater located on its outer periphery. In induction heating, the container or antifouling material is heated by electromagnetic induction from an externally located induction coil.

[0155] Figure 3 The vapor deposition apparatus 3 shown includes a guide plate (not shown) for guiding the vapor deposition material evaporated from the vapor deposition source 43 to a predetermined position, a film thickness gauge (not shown) for observing the thickness of the anti-fouling layer 15 formed by vapor deposition, a vacuum barometer (not shown) for measuring the pressure inside the chamber 33, and a power supply device (not shown).

[0156] The guide plate can be of any shape as long as it can guide the evaporated deposited material to the desired position. If the guide plate is not needed, it can be omitted.

[0157] As a vacuum pressure gauge, it can be used, for example, as an ion meter.

[0158] As a power supply device, examples include high-frequency power supplies.

[0159] <Roller winding device>

[0160] Figure 3 The roller winding device 5 shown has a chamber 35 with a predetermined reduced pressure atmosphere inside, and one or more vacuum pumps 21 that discharge the gas in the chamber 35 to form a reduced pressure atmosphere. Figure 3 (One of them) and a winding roller 24 and a guide roller 22 disposed in the chamber 35.

[0161] A transparent substrate 11 (optical laminate 10) having layers up to an anti-fouling layer 15 formed on its surface is wound on a winding roller 24. The winding roller 24 and the guide roller 22 wind the optical laminate 10 at a specified winding speed.

[0162] A carrier membrane may also be used if needed.

[0163] The vacuum pump 21 included 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 cryogenic pump, a sputtering ion pump, a suction pump, etc. The vacuum pump 21 is appropriately selected or combined in each of the chambers 31, 32, 33, 34, and 35 to create the desired reduced pressure state.

[0164] 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 evaporation apparatus 3 at the desired reduced pressure; the location and number of the vacuum pump 21 in the manufacturing apparatus 20 are not particularly limited. Furthermore, in Figure 3 In the manufacturing apparatus 20 shown, the roll unwinding device 4, the pretreatment device 2A, the sputtering device 1, the pretreatment device 2B, the vapor deposition device 3, and the roll winding device 5 are connected. Therefore, the vacuum pump 21 can be installed in chambers 31, 32, 33, 34, and 35 respectively. As long as the chamber 31 of the sputtering device 1 and the chamber 33 of the vapor deposition device 3 can be maintained at the desired depressurization state, it can also be installed in only a portion of the chambers 31, 32, 33, 34, and 35.

[0165] Next, use Figure 3 The manufacturing apparatus 20 shown describes a method for continuously performing a first surface treatment process, an adhesive layer formation process, an optical functional layer formation process, a second surface treatment process, and an antifouling layer formation process while maintaining the optical laminate 10 in a depressurized state during manufacturing.

[0166] First, an unwinding roller 23 is installed in the chamber 34 of the unwinding device 4. The unwinding roller 23 is wound with a transparent substrate 11 on which a hard coating 12 is formed. Then, the unwinding roller 23 and the guide roller 22 are rotated to feed the transparent substrate 11 with the hard coating 12 on its surface to the pretreatment device 2A at a predetermined conveying speed.

[0167] Next, a first surface treatment process is performed in chamber 32 of the pretreatment apparatus 2A as a pretreatment for the surfaces on which the sealing layer 13 and the optical functional layer 14 are to be formed. In this embodiment, the first surface treatment process is performed on the transparent substrate 11 on which the hard coating 12 is formed.

[0168] In the first surface treatment process, the roller 26 and the guide roller 22 are rotated, and the transparent substrate 11 with the hard coating 12 is conveyed at a specified conveying speed while the surface of the hard coating 12 traveling on the roller 26 is treated.

[0169] As a surface treatment method for the hard coating 12, glow discharge treatment, plasma treatment, ion etching, alkaline treatment, etc., can be used. As described above, glow discharge treatment is preferred because it allows for large-area processing.

[0170] Next, the bonding layer formation process and the optical functional layer formation process are performed in the chamber 31 of the sputtering apparatus 1. Specifically, the film-forming roller 25 and the guide roller 22 are rotated, and while the transparent substrate 11 with the hard coating 12 is conveyed at a specified conveying speed, the bonding layer 13 and the optical functional layer 14 are formed on the hard coating 12 traveling on the film-forming roller 25.

[0171] In this embodiment, by changing the material of the target provided in each film-forming section 41 or the type and flow rate of the reactive gas supplied from the gas supply section and performing sputtering, a sealing layer 13 is formed, on which a high refractive index layer 14a and a low refractive index layer 14b are alternately layered. That is, the sealing layer formation process and the optical functional layer formation process are performed continuously within the sputtering apparatus 1. Thus, the sealing layer 13 and the optical functional layer 14, which serves as an anti-reflection layer, are formed.

[0172] The high refractive index layer 14a and the low refractive index layer 14b are formed under conditions below a specified vacuum level. Specifically, the high refractive index layer 14a is formed under a vacuum level of less than 1.0 Pa, and the low refractive index layer 14b is formed under a vacuum level of less than 0.5 Pa.

[0173] When forming a SiOx film as the sealing layer 13, it is preferable to use a silicon target and form it by reactive sputtering based on a mixed gas atmosphere of oxygen and argon.

[0174] When the adhesive layer 13, the high-refractive-index layer 14a, and the low-refractive-index layer 14b are continuously stacked by sputtering, the target material can be changed during the deposition of the adhesive layer 13, the high-refractive-index layer 14a, and the low-refractive-index layer 14b. Alternatively, for example, a single material can be used as the target, and by changing the oxygen (reactive gas) flow rate during sputtering, layers composed of the target material and layers composed of oxides of the target material can be alternately formed as the adhesive layer 13, the high-refractive-index layer 14a, and the low-refractive-index layer 14b.

[0175] The sputtering pressure used to form the bonding layer 13 and the optical functional layer 14 varies depending on the metal being sputtered, and can be 2 Pa or less, preferably 1 Pa or less, more preferably 0.6 Pa or less, and particularly preferably 0.2 Pa or less. When the sputtering pressure is reduced to 1 Pa or less, the mean free path of the film-forming molecules becomes longer, resulting in higher energy and direct stacking of the molecules, thus forming a denser and better film. The sputtering pressures for high-refractive-index layers and low-refractive-index layers are preferably different. This is because the mean free path differs for each type of film. By varying the pressure for each type of film, a denser film can be formed.

[0176] Then, the transparent substrate 11, on which the adhesive layer 13 and the optical functional layer 14 are formed on the hard coating 12, is sent to the pretreatment device 2B by the rotation of the film forming roller 25 and the guide roller 22.

[0177] Next, a second surface treatment process is performed in chamber 32 of the pretreatment apparatus 2B as a pretreatment for the surface to which the antifouling layer 15 is to be formed. In this embodiment, the transparent substrate 11 with the optical functional layer 14 formed by the optical functional layer formation process is not exposed to the atmosphere, and the second surface treatment process is performed continuously under a reduced pressure.

[0178] In the second surface treatment process, the roller 26 and the guide roller 22 are rotated, and while conveying the transparent substrate 11 on which each layer up to the optical functional layer 14 is formed at a specified conveying speed, the surface of the optical functional layer 14 traveling on the roller 26 is subjected to discharge treatment.

[0179] For example, surface treatment methods for the optical functional layer 14 can include glow discharge treatment, plasma treatment, ion etching, and alkaline treatment. Among these, glow discharge treatment is preferred because it allows for large-area processing.

[0180] When the surface of the optical functional layer 14 is subjected to a discharge process, 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 represented by the surface roughness Ra or the average length RSm of the element. For example, in the case of a transparent antireflective film with a haze of 2.0 or less for the optical functional layer 14, the surface state of the optical functional layer 14 is easily defined by the surface roughness Ra. Alternatively, for example, in the case of an AG-type antireflective film with a haze of more than 2.0 for the optical functional layer 14, the surface state of the optical functional layer 14 is easily defined by the average length RSm of the element. The surface roughness Ra and the average length RSm of the element are measured according to JIS B0601 (ISO 4287).

[0181] Then, the transparent substrate 11 with the surface treated of the optical functional layer 14 is fed into the vapor deposition apparatus 3 by the rotation of the roller 26 and the guide roller 22.

[0182] Next, an antifouling layer formation process is performed in chamber 33 of the vapor deposition apparatus 3. In this embodiment, the antifouling layer formation process is performed continuously under reduced pressure without exposing the transparent substrate 11, which has undergone surface treatment of the optical functional layer 14 obtained through the second surface treatment process, to the atmosphere.

[0183] In the antifouling layer formation process, the guide roller 22 is rotated while the transparent substrate 11 with surface treatment of the optical functional layer 14 is conveyed at a specified conveying speed, and the vapor deposition source 43 is vapor deposited on the surface of the optical functional layer 14.

[0184] In this embodiment, for example, the antifouling material, which is composed of a fluorine-based organic compound that forms the antifouling layer 15, is heated to the vapor pressure temperature by the heating device 53, and the resulting evaporated gas is supplied from the vapor deposition source 43 under reduced pressure so that it adheres to the surface-treated optical functional layer 14, and the antifouling layer 15 is formed by vacuum vapor deposition.

[0185] The pressure during vacuum evaporation of the antifouling layer 15 is preferably 0.05 Pa or less, more preferably 0.01 Pa or less, and particularly preferably 0.001 Pa or less. When the pressure during vacuum evaporation is reduced to 0.05 Pa or less, the mean free path of the film-forming molecules is longer, and the evaporation energy is higher, thus a denser and better antifouling layer 15 can be obtained.

[0186] Using the above method, an optical laminate 10 is obtained in which an antifouling layer 15 is formed on the sputtered bonding layer 13 and the optical functional layer 14 by vacuum evaporation. Preferably, the initial amount of fluorine in the antifouling layer 15 after film formation is 0.03 or more, as determined by X-ray fluorescence analysis (XRF).

[0187] Then, by rotating the guide roller 22, the transparent substrate 11 (optical laminate 10) with each layer up to the anti-fouling layer 15 is fed to the roller winding device 5.

[0188] Then, within the chamber 35 of the roller winding device 5, the optical laminate 10 is wound onto the winding roller 24 by the rotation of the winding roller 24 and the guide roller 22.

[0189] In this embodiment, it is preferable to perform the optical functional layer formation process and the antifouling layer formation process continuously under reduced pressure. This is especially true for applications such as... Figure 3In the case where the optical laminate 10 is continuously manufactured using a roll-to-roll winding method as in the manufacturing method of this embodiment of the manufacturing apparatus 20 shown, it is more preferable to perform the optical functional layer formation process and the antifouling layer formation process continuously online while maintaining a depressurized state. Online 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 continuously performing the optical functional layer formation process and the antifouling layer formation process under depressurized conditions, the formation of a natural oxide film on the optical functional layer 14 formed in the optical functional layer formation process is suppressed before the formation of the antifouling layer 15. In addition, it is possible to prevent contaminants such as foreign matter from adhering to the optical functional layer 14 when it is wound onto the roll, thus preventing the adhesion between the optical functional layer 14 and the antifouling layer 15. Therefore, compared with 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 depressurization, and then placed back into the chamber to perform the antifouling layer formation process under depressurization, an optical laminate with good adhesion between the optical functional layer 14 and the antifouling layer 15 and excellent transparency can be obtained.

[0190] Furthermore, the antifouling layer 15 of the optical laminate 10 in this embodiment is a vapor-deposited film, thus exhibiting higher wear resistance compared to antifouling films formed by coating. This is presumably due to the following reason: antifouling films formed by coating contain voids caused by solvents contained in the coating material. In contrast, vapor-deposited films do not contain voids caused by solvents. Therefore, it is presumed that vapor-deposited films have a higher density than antifouling films formed by coating, resulting in higher wear resistance and alkali resistance.

[0191] The manufacturing method of the optical laminate 10 in this embodiment includes an adhesive layer forming step to form an adhesive layer 13, an optical functional layer forming step to form an optical functional layer 14 by alternately stacking a high refractive index layer 14a and a low refractive index layer 14b, a second surface treatment step to treat the surface of the optical functional layer 14, and an anti-fouling layer forming step to form an anti-fouling layer 15 on the surface-treated optical functional layer 14. Therefore, the optical functional layer 14 and the anti-fouling layer 15 formed on the optical functional layer 14 have good adhesion, and the friction resistance and alkali resistance are even better.

[0192] In this embodiment, when the first surface treatment process, the optical functional layer formation process, the second surface treatment process, and the antifouling layer formation process are performed continuously while the optical laminate is maintained in a depressurized state during manufacturing, the depressurization conditions in the chamber can be different, for example, in sputtering apparatus and vapor deposition apparatus, as long as it does not interfere with each manufacturing process.

[0193] In this embodiment, it is preferable to measure the film formation result over time using a measuring instrument in one or more of the steps of forming the adhesive layer, the optical functional layer, and the antifouling layer, and then feed the result back to the conditions of the manufacturing step corresponding to the subsequent step. This facilitates the optimization of the overall characteristics of the optical laminate and enables uniform in-plane characteristics of the optical laminate. Furthermore, the measuring instrument can also provide feedback on the manufacturing conditions within the same step. In this case, the film formed in this step has uniform and stable characteristics.

[0194] In this embodiment, an example is given where a second surface treatment step is performed between the optical functional layer formation step and the antifouling layer formation step. However, the second surface treatment step can be performed as needed or omitted. If the second surface treatment step is omitted, it is preferable to perform the optical functional layer formation step and the antifouling layer formation step continuously under reduced pressure.

[0195] Furthermore, in the manufacturing method of this embodiment, the optical functional layer is formed under conditions below a specified vacuum level. Therefore, the optical functional layer 14 becomes denser, water vapor transmittance is reduced, and abrasion resistance and alkali resistance are improved. Furthermore, by making the antifouling layer film thickness at or above a specified thickness, sufficient scratch resistance and alkali resistance can be ensured.

[0196] In this embodiment, a device comprising a pretreatment apparatus 2A, a sputtering apparatus 1, a pretreatment apparatus 2B, a vapor deposition apparatus 3, a roll unwinding apparatus 4, and a roll winding apparatus 5 is used. Figure 3 The example described is a manufacturing apparatus 20 used to continuously manufacture the optical laminate 10 in a roll-to-roll manner. However, the manufacturing apparatus for manufacturing the optical laminate 10 is not limited to this type. Figure 3 The manufacturing apparatus 20 shown.

[0197] For example, the pretreatment devices 2A and 2B may be omitted, and a manufacturing apparatus consisting of a roll unwinding device 4, a sputtering device 1, a vapor deposition device 3, and a roll winding device 5 connected in sequence may be used instead.

[0198] exist Figure 3 In the manufacturing apparatus 20 shown, a pretreatment chamber (not shown) for cleaning the surface of the optical functional layer 14 on which the anti-fouling layer 15 is formed may also be provided between the chamber 33 of the vapor deposition apparatus 3 and the chamber 32 of the pretreatment apparatus 2B.

[0199] exist Figure 3 In the manufacturing apparatus 20 shown, a post-processing chamber (not shown) may also be provided 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 anti-fouling layer 15 is formed.

[0200] exist Figure 3 In the manufacturing apparatus 20 shown, a hard coating forming apparatus for forming a hard coating 12 on the surface of the transparent substrate 11 may also be provided between the roll unwinding apparatus 4 and the sputtering apparatus 1. In this case, not only the optical functional layer 14 and the anti-fouling layer 15, but also the hard coating 12 can be manufactured continuously in a roll-to-roll manner, which is preferable.

[0201] In this embodiment, the optical functional layer formation process is described using a sputtering apparatus and the antifouling layer formation process is described using a vapor deposition apparatus. However, without performing a second surface treatment process, the optical functional layer formation process and the antifouling layer formation process can also be performed in the same apparatus (one chamber).

[0202] In the optical laminate 10 of this embodiment, various layers can be provided on the surface of the transparent substrate facing the surface where optical functional layers are formed, as needed. For example, an adhesive layer for bonding with other components can also be provided. In addition, other optical films can be provided through the adhesive layer. Examples of other optical films include films that function as polarizing films, phase difference compensation films, half-wavelength plates, and quarter-wavelength plates.

[0203] Alternatively, layers with functions such as anti-reflection, selective reflection, anti-glare, polarization, phase difference compensation, viewing angle compensation or magnification, light guiding, diffusion, brightness enhancement, color tone adjustment, and conductivity can be directly formed on the opposite surface of the transparent substrate.

[0204] Furthermore, the shape of the optical laminate can be a smooth shape or a nanoscale uneven structure with features such as a moth's eye or anti-glare display. It can also be a geometric shape ranging from micrometers to millimeters, such as a lens or prism. The shape can be formed, for example, through a combination of photolithography and etching, shape transfer, hot pressing, etc. In this embodiment, since the film is formed by vapor deposition or the like, the uneven shape can be maintained even when the substrate has an uneven shape.

[0205] In this embodiment, the optical laminate 10 is provided on the display surface of an image display unit such as a liquid crystal display panel or an organic EL display panel. Therefore, for example, high wear resistance and alkali resistance can be imparted to the touch panel display unit of a smartphone or operating device, enabling the realization of an image display device with excellent durability suitable for practical use.

[0206] Furthermore, the object is not limited to an image display device. For example, any object that can be equipped with the optical laminate 10, such as window glass, goggles, light-receiving surface of a solar cell, screen of a smartphone, display of a laptop PC, information input terminal, tablet terminal, AR (augmented reality) device, VR (virtual reality) device, electro-optical display panel, glass table surface, game console, operation assistance device of an airplane or train, navigation system, instrument panel, or surface of an optical sensor, can be an object.

[0207] The embodiments of the present invention have been described above, but these embodiments are provided as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, 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, and are also included within the scope of the invention as described in the claims and its equivalents.

[0208] For example, an anti-glare layer can be formed instead of the hard coating 12, or any functional layer such as a soft coating with flexibility can be added as needed. They can also be stacked.

[0209] Example

[0210] The embodiments of the present invention will be described below. It should be noted that the optical laminates fabricated in the following embodiments and comparative examples are examples of functions as antireflective films, and the scope of the present invention is not limited to these.

[0211] <Preparation of compositions for hard coating>

[0212] First, a photocurable composition 1 was prepared, containing silica particles (filler) with an average particle size of 50 nm at a content of 28% by mass relative to the total solid content of the composition. Composition 1 is shown in Table 1. The acrylate (adhesive resin), silica particles, and photopolymerization initiator were dissolved in a solvent, and a leveling agent was further added for adjustment.

[0213] [Table 1]

[0214]

[0215] CN 968: Hexafunctional aliphatic urethane acrylates with a polyester backbone

[0216] SR 610: Polyethylene glycol diacrylate, with an average molecular weight of 600 for the polyethylene glycol chains.

[0217] PGM-AC-4130Y: A silica sol surface-modified with a silane compound containing a methacrylamide group, dispersed by propylene glycol monomethyl ether as the dispersion medium.

[0218] Ominirad 184: 1-Hydroxy-cyclohexyl-phenyl-ketone

[0219] (Example 1)

[0220] Using a PET film with a thickness of 50 μm as the transparent substrate, after coating the above Composition 1 on the PET film using a rod coater, the Composition 1 was photo-polymerized to form a hard coat with a thickness of 5 μm on the transparent substrate.

[0221] Next, the surface of the hard coat was surface-treated by glow discharge treatment with an electrode power density of 5500 W / m 2 . Next, on the hard coat, using a Si target and a Nb target as sputtering targets, a mixed gas of Ar gas and O2 gas was used, and a conformal layer and an optical functional layer were continuously formed by reactive sputtering.

[0222] That is, a conformal layer composed 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 composed of Nb2O5 with a thickness of 10 nm, a first low refractive index material layer composed of SiO2 with a thickness of 26 nm, a second high refractive index material layer composed of Nb2O5 with a thickness of 110 nm, and a second low refractive index material layer composed of SiO2 with a thickness of 85 nm were sequentially formed on the hard coat.

[0223] Next, at a chamber pressure of 0.01 Pa, an evaporation temperature of 230 °C, and a holding time of 7.2 s, an anti-fouling layer with a thickness of 3 nm composed of an alkoxysilane compound (KY 1903-1, manufactured by Shin-Etsu Chemical Co., Ltd.) having a perfluoropolyether group was formed by evaporation on the uppermost SiO2 film of the optical functional layer to produce the optical laminate (anti-reflection film) of the example.

[0224] (Example_2)

[0225] Except that the electrode power density during glow discharge treatment was changed from 550 W / m 2 to 1100 W / m 2 , an optical laminate was obtained in the same manner as in Example 1.

[0226] (Example 3)

[0227] Except that the electrode power density of the glow discharge treatment was changed from <5500> W / m 2 to <6600> W / m 2 , an optical laminate was obtained in the same manner as in Example 1.

[0228] (Example 4)

[0229] Except that the thickness of the hard coating formed on the transparent substrate is 2 μm, an optical laminate is obtained in the same manner as in Example 1.

[0230] (Example 5)

[0231] Except for changing the composition for the hard coating to composition 2, an optical laminate was obtained in the same manner as in Example 1.

[0232] (Example 6)

[0233] Except for changing the composition for the hard coating to composition 3, an optical laminate was obtained in the same manner as in Example 1.

[0234] (Example 7)

[0235] As a transparent substrate, a 23μm PET film was used instead of a 50μm thick PET film, otherwise, an optical laminate was obtained in the same manner as in Example 1.

[0236] (Example 8)

[0237] Except that the thickness of the hard coating formed on the transparent substrate is set to 10 μm, the optical laminate is obtained in the same manner as in Example 1.

[0238] (Example 9)

[0239] In addition to increasing the electrode power density during glow discharge processing from 5500 W / m 2 Change to 3300W / m 2 In addition, an optical laminate was obtained in the same manner as in Example 8.

[0240] (Example 10)

[0241] In addition to increasing the electrode power density during glow discharge processing from 5500 W / m 2 Change to 1100W / m 2 In addition, an optical laminate was obtained in the same manner as in Example 8.

[0242] (Example 11)

[0243] In addition to increasing the electrode power density during glow discharge processing from 5500 W / m 2 Change to 550W / m 2 In addition, an optical laminate was obtained in the same manner as in Example 8.

[0244] (Comparative Example 1)

[0245] The composition 1 forming the hard coating was changed to composition 4 shown in Table 1, and the electrode power density during glow discharge treatment was set to 5000 W / m. 2 In addition, an optical laminate is obtained in the same manner as in Example 1.

[0246] (Comparative Example 2)

[0247] The thickness of the hard coating formed on the transparent substrate was set to 10 μm, and the electrode power density during glow discharge treatment was set from 5000 W / m. 2 Change to 1100W / m 2 In addition, an optical laminate was obtained in the same manner as in Comparative Example 1.

[0248] Next, the optical laminates obtained in Examples 1-11 and Comparative Examples 1-2 were measured and evaluated using the following methods.

[0249] <Bending Test>

[0250] As a sample, an optical laminate was prepared to be cut into 1cm × 15cm pieces. It was confirmed that the optical laminate had no cracks on the cut surface.

[0251] A 5.0 mm mandrel was set on a bending tester capable of setting the mandrel. The aforementioned optical laminate was placed on the tester with the antifouling layer facing outwards. Then, the optical laminate was bent 180° using a 2-second bending tester and held for 10 seconds. The presence or absence of cracks in the antifouling layer was then checked visually and with an optical microscope.

[0252] The above steps were repeated while replacing the smaller mandrels every 0.2 mm until cracks and other abnormalities were observed on the antifouling layer side surface of the optical laminate by visual inspection and optical microscope. The diameter (φmm) of the mandrel that was 0.2 mm larger than the diameter of the mandrel where the crack was first found was taken as the test result of the bending test.

[0253] Similarly, the same test was performed on the optical laminate placed in the aforementioned testing machine with the anti-fouling layer formed on the inward-facing side. The diameter (φmm) of the mandrel that was 0.2mm larger than the diameter of the mandrel where the crack was first discovered was taken as the test result of the bending test.

[0254] In addition, the theoretical elongation S (%) of the optical functional layer was calculated when using a mandrel with the smallest diameter that does not produce cracks. The elongation S was calculated as follows.

[0255] S(%) = {(R2 / R1) - 1} × 100

[0256] (Where R2 is the distance from the center of the aforementioned mandrel to the outer surface of the aforementioned optical laminate, and R1 is the distance from the center of the aforementioned mandrel to an imaginary line representing a position equivalent to 1 / 2 of the total thickness of the aforementioned optical laminate.)

[0257] Furthermore, for the case where the antifouling layer is bent inwards, the theoretical compressibility C (%) of the optical functional layer is calculated when using a mandrel with the smallest diameter that does not produce cracks. The compressibility C is calculated as follows.

[0258] C(%) = {1 - (R3 / R1)} × 100

[0259] (Where R3 is the distance from the center of the aforementioned mandrel to the antifouling layer side surface of the aforementioned optical laminate, and R1 is the distance from the center of the aforementioned mandrel to an imaginary line representing a position equivalent to 1 / 2 of the total thickness of the aforementioned optical laminate.)

[0260] It should be noted that three samples were prepared for each measurement, and each value was calculated by averaging the three measurements. Additionally, the minimum mandrel diameter was 1.0 φ mm. While 1.0 φ mm was used in the elongation measurement, since no cracks were produced, the result for the bending test was less than 1.0 φ mm.

[0261] <Madall hardness>

[0262] Using compositions 1 to 4, laminates (samples) with only a hard coating formed on a transparent substrate were prepared.

[0263] For the optical laminates obtained in Examples 1-11 and Comparative Examples 1-2, the martensitic hardness of the antifouling layer side of the optical laminates was measured. For laminates with only a hard coating, the martensitic hardness of the hard coating side of the laminates was measured. The measurements were performed according to ISO 14577-1 using a micro-compression testing machine (Elionix, ENT-NEXUS, measuring indenter: Glass indenter). For the optical laminates, the hardness at an indentation depth of 50 nm was determined; for the laminates with only a hard coating, the hardness at an indentation depth of 1 / 10 of the hard coating thickness was determined.

[0264] Furthermore, the martensitic hardness of the optical laminate measured above is set as (A), and the martensitic hardness of the laminate with only a hard coating formed on a transparent substrate is set as (B), and their ratio (A) / (B) is calculated. The results are shown in Table 2.

[0265] In addition, the optical laminates obtained in Examples 1 to 11 and Comparative Examples 1 to 2 were measured and evaluated using the following methods.

[0266] <Contact Angle Measurement Test for Pure Water>

[0267] The contact angle was measured using an automated DM-700 contact angle meter (manufactured by Kyowa Interface Chemical Co., Ltd.) under the following conditions via elliptic fitting. Pure water was placed in a glass syringe, a stainless steel needle was attached to its tip, and pure water was added dropwise to the optical laminate (test piece).

[0268] The amount of pure water added is 2.0 μL.

[0269] Measurement temperature: 25℃

[0270] Add pure water to the laminate (sample) and measure the contact angle at any 6 points on the surface of the test piece after 4 seconds. Take the average value as the pure water contact angle.

[0271] <Steel wool sliding test>

[0272] Using a friction testing machine of type I according to JIS L0849, the friction body is moved horizontally back and forth along the surface of the optical laminate (test piece) to obtain the test piece.

[0273] Steel wool (BONSTAR Co., Ltd. #0000) was used as the friction material. The test setup was set to a load of 1000 g / cm². 2 Set the sliding distance to 50mm, the sliding speed to 60rpm (1 reciprocation / second), and the number of sliding cycles to 200 (100 reciprocations).

[0274] The sample after sliding was subjected to the same test as the contact angle test for pure water described above, and the difference in contact angle before and after the test was determined.

[0275] The results are shown in Table 3.

[0276] [Table 2]

[0277]

[0278] [Table 3]

[0279]

[0280] As shown in Table 2, in Examples 1-7, the ratio ((A) / (B)) of the Martens hardness (A) of the antifouling layer side of the optical laminate to the Martens hardness (B) of the hard coating side of the laminate having only a transparent substrate and a hard coating is 3.6 or less, thus achieving excellent hardness and further improving bending resistance. In particular, it is believed that the silica particles contained in the hard coating are surface-modified by methacryloyl groups from silane compounds containing methacryloyl groups, resulting in a stronger bond between the methacryloyl groups and the acrylate (adhesive resin), thereby increasing the hardness of the optical laminate. Furthermore, it is known that the adhesion between the hard coating and the adhesive layer, and between the adhesive layer and the optical functional layer, is further improved through the methacryloyl groups on the surface of the silica particles, further enhancing bending resistance.

[0281] Furthermore, it is known that in Examples 1-7, the difference in contact angle with water before friction and after friction by making the steel wool reciprocate horizontally 200 times is less than 20°. It is believed that the silica particles contained in the hard coating are surface modified by the methacryloyl groups from the silane compound containing methacryloyl groups. The methacryloyl groups are more firmly bonded to the acrylate (adhesive resin). As a result, the hardness of the optical laminate is improved, and excellent scratch resistance can be achieved.

[0282] Furthermore, as shown in Table 3, Examples 8-11, like Examples 1-7, exhibited a water contact angle difference of less than 20° between the initial friction and the friction after 200 horizontal reciprocating motions of the steel wool. This improved the hardness of the optical laminate and resulted in excellent scratch resistance. Additionally, the ratio (A) / (B) of the Martens hardness of the antifouling layer side of the optical laminate to the Martens hardness of the hard coating side of the laminate consisting only of a transparent substrate and a hard coating is less than 3.6, thus achieving excellent hardness and further improving bending resistance.

[0283] On the other hand, in Comparative Example 1, when a hard coating was formed using composition 4 containing unmodified silica particles, the ratio ((A) / (B)) was 3.71, resulting in lower hardness of the laminate. Furthermore, the elongation S (outer bending) was 1.22, and the compression ratio C (inner bending) was 4.4, indicating poor bending resistance.

[0284] Furthermore, in Comparative Example 2, when a hard coating was formed using Composition 2 containing unmodified silica particles, the contact angle difference became 23.6°, indicating a decrease in scratch resistance. Additionally, the elongation S (outer bending) was 1.29, and the compression ratio C (inner bending) was 3.63, indicating poor bending resistance.

[0285] Explanation of reference numerals in the attached figures

[0286] 10, 102… Optical laminate, 11… Transparent substrate, 12… Hard coating, 13… Adhesive layer, 14… Optical functional layer, 14a… High refractive index layer, 14b… Low refractive index layer, 15… Antifouling layer, 20… Manufacturing apparatus, 1… Sputtering apparatus, 2A, 2B… Pretreatment apparatus, 3… Evaporation apparatus, 4… Roll unwinding apparatus, 5… Roll winding apparatus, 20… Manufacturing apparatus, 21… Vacuum pump, 22… Guide roller, 23… Unwinding roller, 24… Winding roller, 25… Film forming roller, 26… Cylinder roller, 31, 32, 33, 34, 35… Chamber, 41… Film forming section, 42… Plasma discharge apparatus, 43… Evaporation source, 53… Heating apparatus.

Claims

1. An optical laminate, comprising, in sequence, a transparent substrate, a hard coating layer, an adhesive layer composed of sputtered films, an optical functional layer, and an antifouling layer, wherein the optical functional layer is formed by alternately stacking a high-refractive-index layer composed of sputtered films and a low-refractive-index layer with a refractive index lower than the high-refractive-index layer. The hard coating contains silica filler. The optical laminate satisfies the following conditions 1 and 2. Condition 1: The ratio of the martensitic hardness (A) of the optical laminate measured from the antifouling layer side to the martensitic hardness (B) of the laminate having only the transparent substrate and the hard coating layer measured from the hard coating layer side, i.e., (A) / (B), is 3.6 or less. Condition 2: Using a friction tester based on JIS L0849 with steel wool, the difference in the contact angle with water before friction and after friction by making the steel wool reciprocate horizontally 200 times is less than 20°.

2. The optical laminate according to claim 1, wherein, The silica filler was surface-modified with functional groups derived from silane compounds.

3. The optical laminate according to claim 2, wherein, The silane compound is selected from one or more of the following: silane compounds containing vinyl groups, silane compounds containing (meth)acryloyl groups, silane compounds containing amino groups, silane compounds containing isocyanate groups, silane compounds containing isocyanurate groups, silane compounds containing epoxy groups, and silane compounds containing mercapto groups.

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

5. The optical laminate according to claim 2, wherein, The hard coating contains an adhesive resin and a silica filler, wherein the functional groups derived from the silane compound have the same functional groups as the adhesive resin.

6. The optical laminate according to claim 5, wherein, The adhesive resin contains a (meth)acrylate compound, 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 below 800 nm.

8. The optical laminate according to claim 1, wherein, The thickness of the hard coating is greater than 0.5 μm and less than 100 μm.

9. The optical laminate according to claim 1, wherein, When the optical laminate is bent 180° with the side having the antifouling layer facing outward, the elongation S of the optical functional layer, calculated by the following formula (1) as a percentage, when using a mandrel with the smallest diameter that does not produce cracks, satisfies 1.3 ≤ S. S(%)={(R2 / R1)-1}×100···(1) Wherein, R2 is the distance from the center of the mandrel to the outer surface of the optical laminate, and R1 is the distance from the center of the mandrel to an imaginary line representing a position equivalent to 1 / 2 of the total thickness of the optical laminate.

10. The optical laminate according to claim 9, wherein, When the optical laminate is bent 180° with the surface having the antifouling layer facing inward, the compression ratio C of the optical functional layer, calculated by the following formula (2) as a percentage, satisfies 4.5 ≤ C when using a mandrel with the smallest diameter that does not produce cracks. C(%)={1-(R3 / R1)}×100···(2) Wherein, R3 is the distance from the center of the mandrel to the antifouling layer side surface of the optical laminate, and R1 is the distance from the center of the mandrel to an imaginary line representing a position equivalent to 1 / 2 of the total thickness of the optical laminate.

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

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