Method for manufacturing optical laminate

Abstract

To provide a method for manufacturing an optical laminate including an antifouling layer excellent in durability.SOLUTION: The method for manufacturing an optical laminate according to the present invention manufactures an optical laminate formed by laminating a plastic film, an adhesion layer, an optical functional layer, and an antifouling layer in order and includes: an adhesion layer formation step of forming an adhesion layer; an optical functional layer formation step of forming an optical functional layer; a surface treatment step of subjecting a surface of the optical functional layer to a glow discharge treatment; and an antifouling layer formation step of forming an antifouling layer on the surface-treated optical functional layer. The integrated output of the glow discharge treatment is 130 W min / m2 or more and 2,000 W min / m2 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing an optical laminate. [Background technology]

[0002] For example, in flat panel displays (FPDs), touch panels, solar cells, etc., various antireflection films are used as optical laminates to prevent surface reflection. Conventionally, an antireflection film has been proposed that includes a multilayer film in which a high refractive index layer and a low refractive index layer are sequentially laminated on a transparent substrate. An antifouling layer (surface protection layer) is generally formed on the outermost surface of such an antireflection film for the purpose of protecting the surface and preventing fouling.

[0003] In recent years, anti-reflection films (optical laminates) have been widely used in touch panels of smartphones and various operating devices, which has led to a demand for improved abrasion resistance of optical laminates. For example, Patent Document 1 discloses a transparent substrate laminate in which the abrasion resistance is improved by adjusting the amount of fluorine contained in the constituent material of the antifouling layer to a specific range.

[0004] Patent Document 2 describes a method for forming an antifouling layer, which involves pretreating at least one surface of a substrate to be treated before forming the antifouling layer, and then forming the antifouling layer on the pretreated surface. Patent Document 2 also describes that the pretreatment is any of a high-frequency discharge plasma method, an electron beam method, an ion beam method, a vapor deposition method, a sputtering method, an alkali treatment method, an acid treatment method, a corona treatment method, and an atmospheric pressure glow discharge plasma method.

[0005] Patent Document 3 describes a method for producing an antifouling optical article, in which an antireflection film is formed on the surface of a substrate by vapor deposition, oxygen or argon is introduced to perform plasma treatment, and then a fluorine-containing organosilicon compound is vacuum-deposited to form an antifouling layer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2019 / 078313 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-175438 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-301208 [Patent Document 4] Patent No. 6542970 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the transparent substrate laminate described in Patent Document 1 has a problem in that repeated friction causes unreacted substances that contribute to abrasion resistance to be rubbed off, making it impossible to maintain high abrasion resistance. There has been a demand for an optical laminate equipped with an antifouling layer that can maintain high abrasion resistance even against repeated friction.

[0008] The present invention has been made in view of the above problems, and has an object to provide a method for producing an optical laminate having excellent durability. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention proposes the following means.

[0010] [1] A method for producing an optical laminate according to a first aspect of the present invention is a method for producing an optical laminate in which a plastic film, an adhesive layer, an optical functional layer, and an antifouling layer are laminated in this order, an adhesion layer forming step of forming an adhesion layer; an optical function layer forming step of forming an optical function layer; a surface treatment step of treating the surface of the optical functional layer so that the rate of change in surface roughness represented by the following formula (1) is 1 to 25%, or the rate of change in average element length represented by the following formula (2) is 7 to 65%; and an antifouling layer forming step of forming an antifouling layer on the surface-treated optical functional layer: Surface roughness change rate (%) = ((Ra2 / Ra1) - 1) × 100 (%) Equation (1) (In equation (1), Ra1 represents the surface roughness (Ra) of the optical functional layer before the surface treatment, and Ra2 represents the surface roughness (Ra) of the optical functional layer after the surface treatment.) Average element length change rate (%) = ((RSm2 / RSm1)-1) × 100 (%) Equation (2) (In formula (2), Rsm1 represents the average length (RSm) of the elements of the optical functional layer before surface treatment, and RSm2 represents the average length (RSm) of the elements of the optical functional layer after surface treatment.)

[0011] [2] A method for producing an optical laminate according to a second aspect of the present invention is a method for producing an optical laminate in which a plastic film, an adhesive layer, an optical functional layer, and an antifouling layer are laminated in this order, an adhesion layer forming step of forming an adhesion layer; an optical function layer forming step of forming an optical function layer; a surface treatment step of glow discharge treating the surface of the optical functional layer; an antifouling layer forming step of forming an antifouling layer on the surface-treated optical functional layer, The cumulative power of the glow discharge treatment is 130W·min / m 2 More than 2000W min / m 2 The following is the result.

[0012] [3] In the method for producing an optical laminate according to the above aspect, the adhesive layer and the optical functional layer may be formed by sputtering. [4] In the method for producing an optical laminate according to the above aspect, the antifouling layer forming step may form the antifouling layer by vacuum deposition. [5] In the method for producing the optical laminate according to the above aspect, the adhesion layer forming step, the optical functional layer forming step, the surface treatment step, and the antifouling layer forming step may be carried out successively under reduced pressure.

[0013] [6] The method for producing an optical laminate according to the above aspect may include a hard coat layer forming step of forming a hard coat layer before the adhesion layer forming step. [7] In the method for producing an optical laminate according to the above aspect, the optical functional layer may include any one layer selected from an antireflection layer and a selective reflection layer. [8] In the method for producing an optical laminate according to the above aspect, the optical functional layer may include a low refractive index layer.

[0014] [9] In the method for producing an optical laminate according to the above aspect, the optical function layer forming step may be a step of forming a laminate by alternately laminating low refractive index layers and high refractive index layers.

[10] In the method for producing an optical laminate according to the above aspect, the surface of the low refractive index layer may be treated in the surface treatment step.

[11] In the method for producing an optical laminate according to the above aspect, the low refractive index layer may contain a metal oxide.

[0015]

[12] An optical laminate according to a third aspect of the present invention is an optical laminate comprising a transparent substrate, an adhesive layer, an optical functional layer, and an antifouling layer laminated in this order, and the antifouling layer is made of a vapor-deposited film formed by vapor-depositing an antifouling material.

[13] In the optical laminate according to the above embodiment, the optical functional layer may include any one layer selected from an antireflection layer and a selective reflection layer.

[0016]

[14] In the optical laminate according to the above aspect, the optical functional layer may include a low refractive index layer.

[15] In the optical laminate according to the above aspect, the optical functional layer may be a laminate in which low refractive index layers and high refractive index layers are alternately stacked.

[16] In the optical laminate according to the above aspect, the antifouling layer may be provided in contact with the low refractive index layer.

[17] In the optical laminate according to the above aspect, the adhesive layer may contain a metal or a metal oxide.

[0017]

[18] In the optical laminate according to the above aspect, the antifouling material may contain a fluorine-based organic compound.

[19] The optical layered body according to the above embodiment may further include a hard coat layer between the transparent substrate and the adhesive layer.

[20] An article according to a fourth aspect of the present invention comprises the optical laminate according to the above aspect.

[0018]

[21] A fifth aspect of the present invention relates to a method for producing an optical laminate, which is a method for producing an optical laminate according to any of the above aspects, and includes an antifouling layer forming step of forming an antifouling layer on one side of the optical functional layer, the antifouling layer being a vapor-deposited film formed by vacuum deposition of an antifouling material.

[22] The method for producing an optical laminate according to the above aspect may include an optical function layer forming step of forming the optical function layer by sputtering, and the optical function layer forming step and the antifouling layer forming step may be carried out successively under reduced pressure. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a method for producing an optical laminate provided with an antifouling layer having excellent durability. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a cross-sectional view showing an example of an optical laminate of the present embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing another example of the optical laminate of the present embodiment. [Figure 3] FIG. 2 is a cross-sectional view showing another example of the optical laminate of the present embodiment. [Figure 4] FIG. 2 is a schematic diagram illustrating an example of a manufacturing apparatus that can be used in the method for manufacturing an optical laminate of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present embodiment will be described in detail below with reference to the drawings as appropriate. The drawings used in the following description may show characteristic portions enlarged for the sake of clarity, and the dimensional ratios of each component may differ from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto. Appropriate changes can be made within the scope of the present invention.

[0022] [Optical laminate] FIG. 1 is a cross-sectional view illustrating an example of the optical laminate of the present embodiment. As shown in FIG. 1, the optical laminate 101 of this embodiment is formed by laminating a transparent substrate 11, an adhesive layer 13, an optical functional layer 14, and an antifouling layer 15 in this order. The adhesive layer 13 is a layer that provides adhesiveness. The optical function layer 14 is a layer that exhibits an optical function, which is a function that controls the properties of light, such as reflection, transmission, and refraction, and examples thereof include an anti-reflection function, a selective reflection function, and a lens function. The optical functional layer 14 preferably includes any one selected from an antireflection layer and a selective reflection layer. Known antireflection layers, selective reflection layers, and antiglare layers can be used. Each of the antireflection layer, selective reflection layer, and antiglare layer may be a single layer or a laminate of multiple layers.

[0023] FIG. 2 is a cross-sectional view showing another example of the optical laminate of the present embodiment. The optical laminate 102 shown in FIG. 2 is formed by laminating a transparent substrate 11, a hard coat layer 12, an adhesive layer 13, an optical functional layer 14, and an antifouling layer 15 in this order. The adhesive layer 13 is a layer that provides adhesiveness. The optical function layer 14 is a layer that exhibits an optical function. The optical function is a function that controls the properties of light, such as reflection, transmission, and refraction, and examples thereof include an anti-reflection function and a selective reflection lens function. The optical functional layer 14 preferably includes any one selected from an antireflection layer and a selective reflection layer. Known antireflection layers and selective reflection layers can be used. Each of the antireflection layer and selective reflection layer may be a single layer or a laminate of multiple layers.

[0024] FIG. 3 is a cross-sectional view showing another example of the optical laminate of the present embodiment. The optical laminate 10 shown in FIG. 3 is the same as the optical laminate 102 shown in FIG. 2, except that an antireflection layer is provided as the optical functional layer 14. As shown in FIG. 2, the optical functional layer 14 (antireflection layer) is made of a laminate in which low refractive index layers 14b and high refractive index layers 14a are alternately stacked. The optical functional layer 14 shown in FIG. 2 is made of a hard coat layer 12, an adhesive layer 13, a high refractive index layer 14a, a low refractive index layer 14b, a high refractive index layer 14a, a low refractive index layer 14b, and an antifouling layer 15 stacked in this order from the transparent substrate 11 side. Therefore, the antifouling layer 15 is in contact with the low refractive index layer 14b of the optical functional layer 14.

[0025] The transparent substrate 11 may be formed from a transparent material that can transmit light in the visible light range. For example, a plastic film is preferably used as the transparent substrate 11. Specific examples of materials that can be used to form the plastic film include polyester resins, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, and polyphenylene sulfide resins.

[0026] The term "transparent material" as used in the present invention refers to a material having a transmittance of 80% or more for light in the wavelength range used, provided that the effect of the present invention is not impaired. In addition, in this embodiment, "(meth)acrylic" means methacrylic and acrylic.

[0027] The transparent substrate 11 may contain a reinforcing material as long as it does not significantly impair the optical properties. Examples of the reinforcing material include cellulose nanofiber and nanosilica. In particular, polyester-based resins, acetate-based resins, polycarbonate-based resins, and polyolefin-based resins are preferably used as the reinforcing material. Specifically, a triacetyl cellulose (TAC) substrate is preferably used as the reinforcing material. The transparent substrate 11 may also be a glass film, which is an inorganic substrate.

[0028] When the plastic film is a TAC substrate, forming a hard coat layer 12 on one side thereof forms a permeation layer formed by the penetration of some of the components constituting the hard coat layer 12. As a result, the adhesion between the transparent substrate 11 and the hard coat layer 12 is improved, and the occurrence of interference fringes due to the difference in refractive index between the layers can be suppressed.

[0029] The transparent substrate 11 may be a film having optical and / or physical functions. Examples of films having optical and / or physical functions include a polarizing plate, a retardation compensation film, a heat-shielding film, a transparent conductive film, a brightness-enhancing film, and a barrier-enhancing film.

[0030] The thickness of the transparent substrate 11 is not particularly limited, but is preferably, for example, 25 μm or more, and more preferably 40 μm or more. When the thickness of the transparent substrate 11 is 25 μm or more, the rigidity of the substrate itself is ensured, and wrinkles are less likely to occur even when stress is applied to the optical laminate 10. Furthermore, when the thickness of the transparent substrate 11 is 25 μm or more, wrinkles are less likely to occur even when the hard coat layer 12 is continuously formed on the transparent substrate 11, which is preferable as there are fewer concerns about production. When the thickness of the transparent substrate 11 is 40 μm or more, wrinkles are even less likely to occur, which is preferable.

[0031] When the production is carried out using a roll, the thickness of the transparent substrate 11 is preferably 1000 μm or less, and more preferably 600 μm or less. When the thickness of the transparent substrate 11 is 1000 μm or less, the optical laminate 10 during production and the optical laminate 10 after production can be easily wound into a roll, and the optical laminate 10 can be produced efficiently. Furthermore, when the thickness of the transparent substrate 11 is 1000 μm or less, the optical laminate 10 can be made thinner and lighter. When the thickness of the transparent substrate 11 is 600 μm or less, the optical laminate 10 can be produced more efficiently and can be made even thinner and lighter, which is preferable.

[0032] The surface of the transparent substrate 11 may be previously subjected to an etching treatment such as sputtering, corona discharge, ultraviolet irradiation, electron beam irradiation, conversion treatment, oxidation, and / or an undercoat treatment. By previously performing these treatments, adhesion to the hard coat layer 12 to be formed on the transparent substrate 11 can be improved. Furthermore, before forming the hard coat layer 12 on the transparent substrate 11, it is also preferable to remove dust and clean the surface of the transparent substrate 11 by subjecting the surface of the transparent substrate 11 to solvent washing, ultrasonic cleaning, or the like, as necessary.

[0033] A known material can be used as the hard coat layer 12. The hard coat layer 12 may be made of only a binder resin, or may contain a filler together with the binder resin to the extent that transparency is not impaired. The filler may be made of an organic substance, an inorganic substance, or a mixture of organic and inorganic substances.

[0034] The binder resin used in the hard coat layer 12 is preferably transparent, and examples thereof include ionizing radiation curable resins that are cured by ultraviolet light or electron beams, thermoplastic resins, and thermosetting resins.

[0035] Examples of the ionizing radiation curable resin used as the binder resin of the hard coat layer 12 include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, and N-vinylpyrrolidone. Examples of the compound that is an ionizing radiation curable resin having two or more unsaturated bonds include trimethylolpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane ... Examples of suitable polyfunctional compounds include erythritol penta(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, isocyanuric acid tri(meth)acrylate, isocyanuric acid di(meth)acrylate, polyester tri(meth)acrylate, polyester di(meth)acrylate, bisphenol di(meth)acrylate, diglycerin tetra(meth)acrylate, adamantyl di(meth)acrylate, isobornyl di(meth)acrylate, dicyclopentane di(meth)acrylate, tricyclodecane di(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate. Among these, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), and pentaerythritol tetraacrylate (PETTA) are particularly preferred. The term "(meth)acrylate" refers to methacrylate and acrylate. As the ionizing radiation curable resin, the above-mentioned compounds modified with PO (propylene oxide), EO (ethylene oxide), CL (caprolactone), etc. can also be used.

[0036] Examples of thermoplastic resins used as the binder resin of the hard coat layer 12 include styrene-based resins, (meth)acrylic resins, vinyl acetate-based resins, vinyl ether-based resins, halogen-containing resins, alicyclic olefin-based resins, polycarbonate-based resins, polyester-based resins, polyamide-based resins, cellulose derivatives, silicone-based resins, and rubber or elastomers. The thermoplastic resins are preferably amorphous and soluble in organic solvents (particularly common solvents capable of dissolving multiple polymers and curable compounds). In particular, from the viewpoints of transparency and weather resistance, styrene-based resins, (meth)acrylic resins, alicyclic olefin-based resins, polyester-based resins, cellulose derivatives (cellulose esters, etc.), and the like are preferred.

[0037] Examples of thermosetting resins used as the binder resin of the hard coat layer 12 include phenolic resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, aminoalkyd resins, melamine-urea co-condensation resins, silicon resins, and polysiloxane resins (including so-called silsesquioxanes such as cage-shaped and ladder-shaped silsesquioxanes).

[0038] The hard coat layer 12 may contain an organic resin and an inorganic material, or may be an organic-inorganic hybrid material. One example is a layer formed by a sol-gel method. Examples of inorganic materials include silica, alumina, zirconia, and titania. Examples of organic materials include acrylic resin. The filler contained in the hard coat layer 12 can be selected from various types depending on the application of the optical laminate 10, from the viewpoints of antiglare properties, adhesion to the optical functional layer 14 described below, and antiblocking properties. Specifically, known fillers such as silica (oxide of Si) particles, alumina (aluminum oxide) particles, and organic fine particles can be used.

[0039] The hard coat layer 12 may contain, for example, a binder resin and silica particles and / or alumina particles as a filler. By dispersing silica particles and / or alumina particles as a filler in the hard coat layer 12, fine irregularities can be formed on the surface of the hard coat layer 12. These silica particles and / or alumina particles may be exposed on the surface of the hard coat layer 12 facing the optical functional layer 14. In this case, the binder resin of the hard coat layer 12 and the optical functional layer 14 are strongly bonded together. This improves the adhesion between the hard coat layer 12 and the optical functional layer 14, increases the hardness of the hard coat layer 12, and improves the scratch resistance of the optical laminate 10.

[0040] The average particle size of the filler in the hard coat layer 12 is, for example, 800 nm or less, preferably 780 nm or less, and more preferably 100 nm or less. Suitable fillers of this size include, for example, silica particles and alumina particles. When the particle size of the filler is within this range, the haze value of the entire optical laminate 10 is 2% or less. An optical laminate 10 with a haze of 2% or less has high transparency and serves as a so-called clear anti-reflection film.

[0041] The average particle size of the filler in the hard coat layer 12 may be, for example, 0.5 μm or more. Suitable fillers of this size include organic fine particles of acrylic resin, etc. When the particle size of the filler is within this range, the haze value of the entire optical laminate 10 exceeds 2%. An optical laminate 10 with a haze of more than 2% has antiglare properties and serves as a so-called antiglare (AG) type antireflection film. Even in this case, the average particle size of the filler is preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less. As the filler contained in the hard coat layer 12, various reinforcing materials can be used within a range that does not impair the optical properties in order to impart toughness to the hard coat layer 12. Examples of reinforcing materials include cellulose nanofibers.

[0042] The thickness of the hard coat layer 12 is not particularly limited, but is preferably 0.5 μm or more, and more preferably 1 μm or more. The thickness of the hard coat layer 12 is preferably 100 μm or less. When the thickness of the hard coat layer 12 is 0.5 μm or more, sufficient hardness is obtained, making it less susceptible to scratches during production. Furthermore, when the thickness of the hard coat layer 12 is 100 μm or less, the optical laminate 10 can be made thinner and lighter. Furthermore, when the thickness of the hard coat layer 12 is 100 μm or less, microcracks in the hard coat layer 12 that occur when the optical laminate 10 is bent during production are less likely to occur, improving productivity.

[0043] The hard coat layer 12 may be a single layer or a laminate of multiple layers. The hard coat layer 12 may further be provided with known functions such as ultraviolet absorption, antistatic properties, refractive index adjustment, and hardness adjustment. Furthermore, the function imparted to the hard coat layer 12 may be imparted to a single hard coat layer, or may be imparted to a plurality of separate layers.

[0044] The adhesion layer 13 is a layer formed to improve adhesion between the transparent substrate 11 or hard coat layer 12, which is an organic film, and the optical functional layer 14, which is an inorganic film. In the optical laminate 10 shown in FIG. 3, the adhesion layer 13 is provided between the hard coat layer 12 and the optical functional layer 14. The adhesion layer 13 functions to adhere the hard coat layer 12 and the optical functional layer 14. The adhesion layer 13 is preferably made of an oxygen-deficient metal oxide or metal. An oxygen-deficient metal oxide refers to a metal oxide in which the number of oxygen atoms is deficient compared to the stoichiometric composition. Examples of oxygen-deficient metal oxides include SiOx, AlOx, TiOx, ZrOx, CeOx, MgOx, ZnOx, TaOx, SbOx, SnOx, and MnOx. Examples of metals include Si, Al, Ti, Zr, Ce, Mg, Zn, Ta, Sb, Sn, Mn, and In. The adhesion layer 13 may be, for example, SiOx, where x is greater than 0 and less than 2.0. The adhesion layer may also be formed from a mixture of multiple types of metals or metal oxides. The thickness of the adhesive layer is preferably more than 0 nm and not more than 20 nm, particularly preferably 1 nm or more and 10 nm or less, from the viewpoint of maintaining transparency and adhesiveness with the optical functional layer and obtaining good optical properties.

[0045] The optical function layer 14 is a laminate that exhibits an anti-reflection function. The optical function layer 14 shown in Fig. 3 is a laminate of four layers in total, in which high-refractive-index layers 14a and low-refractive-index layers 14b are alternately stacked in this order from the adhesive layer 13 side. The number of high-refractive-index layers 14a and low-refractive-index layers 14b is not particularly limited, and the number of high-refractive-index layers 14a and low-refractive-index layers 14b can be any number.

[0046] 3, the optical functional layer 14 is made of a laminate in which low refractive index layers 14b and high refractive index layers 14a are alternately stacked, and therefore light incident from the antifouling layer 15 side is diffused by the optical functional layer 14. Therefore, an antireflection function is obtained that prevents light incident from the antifouling layer 15 side from being reflected in one direction.

[0047] The low refractive index layer 14b contains, for example, a metal oxide. The low refractive index layer 14b may contain an oxide of Si from the viewpoints of availability and cost, and is preferably a layer whose main component is SiO2 (oxide of Si) or the like. A single SiO2 layer is colorless and transparent. In this embodiment, the main component of the low refractive index layer 14b means a component contained in the low refractive index layer 14b at 50 mass % or more. When the low refractive index layer 14b is a layer mainly composed of an oxide of Si, it may contain less than 50 mass% of another element. The content of elements other than the oxide of Si is preferably 10% or less. Examples of other elements that may be included include Na for improving durability, Zr, Al, or N for improving hardness, and Zr and Al for improving alkali resistance.

[0048] The refractive index of the low refractive index layer 14b is preferably 1.20 to 1.60, and more preferably 1.30 to 1.50. Examples of the dielectric material used for the low refractive index layer 14b include magnesium fluoride (MgF2, refractive index 1.38).

[0049] The refractive index of the high refractive index layer 14a is preferably 2.00 to 2.60, and more preferably 2.10 to 2.45. Examples of dielectric materials that can be used for the high refractive index layer 14a include niobium pentoxide (Nb2O5, refractive index 2.33), titanium oxide (TiO2, refractive index 2.33 to 2.55), tungsten oxide (WO3, refractive index 2.2), cerium oxide (CeO2, refractive index 2.2), tantalum pentoxide (Ta2O5, refractive index 2.16), zinc oxide (ZnO, refractive index 2.1), indium tin oxide (ITO, refractive index 2.06), and zirconium oxide (ZrO2, refractive index 2.2). If it is desired to impart conductive properties to the high refractive index layer 14a, for example, ITO or indium zinc oxide (IZO) can be selected.

[0050] The optical function layer 14 preferably uses, for example, niobium pentoxide (Nb2O5, refractive index 2.33) as the high refractive index layer 14a and SiO2 as the low refractive index layer 14b.

[0051] The film thickness of the low refractive index layer 14b may be in the range of 1 nm to 200 nm, and is appropriately selected depending on the wavelength range in which the anti-reflection function is required. The thickness of the high refractive index layer 14a may be, for example, 1 nm or more and 200 nm or less, and is appropriately selected depending on the wavelength range in which the anti-reflection function is required. The thicknesses of the high refractive index layer 14a and the low refractive index layer 14b can be appropriately selected depending on the design of the optical function layer 14. For example, from the adhesive layer 13 side, the layers may be a high refractive index layer 14a of 5 to 50 nm, a low refractive index layer 14b of 10 to 80 nm, a high refractive index layer 14a of 20 to 200 nm, and a low refractive index layer 14b of 50 to 200 nm.

[0052] Of the layers forming the optical functional layer 14, a low refractive index layer 14b is disposed on the side of the antifouling layer 15. It is preferable that the low refractive index layer 14b of the optical functional layer 14 is in contact with the antifouling layer 15, as this improves the antireflection performance of the optical functional layer 14.

[0053] The antifouling layer 15 is formed on the outermost surface of the optical functional layer 14 and prevents the optical functional layer 14 from being soiled. Furthermore, when the antifouling layer 15 is applied to a touch panel or the like, it suppresses wear of the optical functional layer 14 due to its abrasion resistance. The antifouling layer 15 of this embodiment is made of, for example, a vapor-deposited film formed by vapor-depositing an antifouling material. In this embodiment, the antifouling layer 15 is formed by vacuum-depositing a fluorine-based organic compound as the antifouling material on one surface of the low refractive index layer 14b that constitutes the optical function layer 14. In this embodiment, the antifouling material contains a fluorine-based organic compound, which results in an optical laminate 10 with even better abrasion resistance and alkali resistance.

[0054] A compound comprising a fluorine-modified organic group and a reactive silyl group (e.g., alkoxysilane) is preferably used as the fluorine-based organic compound constituting the antifouling layer 15. Examples of commercially available products include Optool DSX (manufactured by Daikin Corporation) and KY-100 series (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0055] When a compound consisting of a fluorine-modified organic group and a reactive silyl group (e.g., alkoxysilane) is used as the fluorine-based organic compound constituting the antifouling layer 15 and a layer consisting of SiO2 is used as the low refractive index layer 14b of the optical functional layer 14 in contact with the antifouling layer 15, a siloxane bond is formed between the silanol group, which is the skeleton of the fluorine-based organic compound, and the SiO2. This results in good adhesion between the optical functional layer 14 and the antifouling layer 15, which is preferable.

[0056] The optical thickness of the antifouling layer 15 may be in the range of 1 nm or more and 20 nm or less, and preferably in the range of 3 nm or more and 10 nm or less. When the thickness of the antifouling layer 15 is 1 nm or more, sufficient abrasion resistance can be ensured when the optical laminate 10 is used for touch panels, etc. Furthermore, when the thickness of the antifouling layer 15 is 20 nm or less, the time required for vapor deposition can be shortened, allowing for efficient production.

[0057] The surface roughness Ra of the antifouling layer 15 varies depending on the application and configuration of the optical laminate. For example, when the optical laminate is a transparent antireflection layer without antiglare function (clear-type antireflection film), the surface roughness Ra of the antifouling layer 15 is preferably, for example, 3 nm or more. There is no particular upper limit, but from the viewpoint of scratch resistance, for example, it is preferably 9 nm or less. On the other hand, when the optical laminate is an antireflection layer with antiglare function (AG-type antireflection film), the surface roughness Ra of the antifouling layer 15 is preferably, for example, 10 nm or more, and more preferably 30 nm or more. Note that the surface roughness Ra of the antifouling layer 15 referred to here is the value before the scratch resistance test is conducted.

[0058] The average length RSm of the elements of the antifouling layer 15 varies depending on the application and configuration of the optical laminate. For example, when the optical laminate is an antireflection layer having an antiglare function (AG-type antireflection film), the average length RSm of the elements of the antifouling layer 15 is preferably, for example, 59 nm or more, and more preferably 92 nm or less. Note that the average length RSm of the elements of the antifouling layer 15 referred to here is the value before the scratch resistance test is conducted.

[0059] The antifouling layer 15 may contain additives such as light stabilizers, ultraviolet absorbers, colorants, antistatic agents, lubricants, leveling agents, antifoaming agents, antioxidants, flame retardants, infrared absorbers, and surfactants, as needed.

[0060] The antifouling layer 15 formed by vapor deposition is tightly bonded to the optical function layer 14 and is dense with few voids. As a result, the antifouling layer 15 of this embodiment exhibits properties different from those of antifouling layers formed by conventional methods such as coating an antifouling material.

[0061] For example, the antifouling layer 15 of the clear optical laminate 10 of this embodiment has the following properties. (1) After an abrasion test in which steel wool is moved back and forth horizontally 500 times, the difference in the contact angle with water is 12° or less. (2) After an abrasion test in which steel wool is moved back and forth horizontally 500 times, the contact angle with water is 109° or more.

[0062] (3) After an abrasion test in which a cloth (nonwoven fabric wiper) is moved back and forth 4,000 times, the contact angle with water is 108° or more. (4) The change in the L*a*b* values ​​(ΔE value) shown by the following formula (3) using SCI (Specular Component Include, a method of measuring reflected color that takes specular reflection into account) before and after an abrasion test in which steel wool is moved back and forth horizontally 500 times is 3.0 or less.

[0063]

number

[0064] (5) The change in the L*a*b* values ​​(ΔE value) shown by the following formula (4) using SCE (Specular Component Exclude, a method of measuring reflected color that does not take into account specular reflection) before and after an abrasion test in which steel wool is moved back and forth horizontally 500 times is 0.5 or less.

[0065]

number

[0066] (6) The residual fluorine rate measured by X-ray fluorescence analysis (XRF) after immersion in a 0.1 mol / L NaOH solution (liquid temperature 55°C) for 4 hours is 70% or more.

[0067] (7) The fluorine remaining rate measured by X-ray fluorescence analysis (XRF) after the ultrasonic cleaning test is 79% or more.

[0068] Furthermore, for example, the antifouling layer 15 of the AG-type optical laminate 10 of this embodiment has the following properties. (1) After an abrasion test in which a cloth (non-woven fabric wiper) is moved back and forth 4,000 times, the fluorine remaining rate measured by an X-ray photoelectron spectrometer (ESCA) is 78% or more. (2) The residual fluorine rate measured by X-ray fluorescence analysis (XRF) after immersion in a 0.1 mol / L NaOH solution (liquid temperature 55°C) for 4 hours is 90% or more. (3) The fluorine remaining rate measured by X-ray fluorescence analysis (XRF) after the ultrasonic cleaning test is 77% or more.

[0069] The optical laminate 10 including the antifouling layer 15 of this embodiment formed by vapor deposition has fewer voids and is denser than an antifouling layer formed by coating. Furthermore, in the optical laminate 10 of this embodiment, the antifouling layer 15 is firmly bonded to the low refractive index layer 14b that is in contact with the antifouling layer 15. Therefore, the optical laminate 10 of this embodiment has excellent visible light transmittance, can maintain high abrasion resistance against repeated friction, and can also maintain high alkali resistance.

[0070] [Method of manufacturing optical laminate] The optical laminate 10 of this embodiment shown in FIG. 3 can be produced, for example, by the method described below. In this embodiment, as an example of a method for producing the optical laminate 10, a case in which the optical laminate 10 is produced using a transparent substrate 11 wound in a roll shape will be described. First, the transparent substrate 11 wound in a roll shape is unwound. Then, a slurry containing a material for forming the hard coat layer 12 is applied onto the transparent substrate 11 by a known method, and cured by a known method corresponding to the material for forming the hard coat layer 12. In this way, the hard coat layer 12 is formed (hard coat layer forming step). Thereafter, the transparent substrate 11 with the hard coat layer 12 formed on its surface is wound into a roll by a known method.

[0071] Next, an adhesion layer forming step is performed to form an adhesion layer 13 on the hard coat layer 12, and an optical function layer forming step is performed to form an optical function layer 14. Thereafter, an antifouling layer forming step is performed to form an antifouling layer 15 on the optical function layer 14. In this embodiment, it is preferable to perform a first surface treatment step to treat the surface of the hard coat layer 12 before the optical function layer forming step, and then perform the adhesion layer forming step and the optical function layer forming step. Also, in this embodiment, it is preferable to perform a second surface treatment step to treat the surface of the optical function layer 14 after the optical function layer forming step, and then perform the antifouling layer forming step.

[0072] In the method for producing the optical laminate 10 of this embodiment, the first surface treatment step, the adhesion layer formation step, the optical functional layer formation step, the second surface treatment step, and the antifouling layer formation step are preferably performed consecutively while the optical laminate in the middle of production is maintained under reduced pressure. When the first surface treatment step, the adhesion layer formation step, the optical functional layer formation step, the second surface treatment step, and the antifouling layer formation step are performed consecutively while the optical laminate in the middle of production is maintained under reduced pressure, for example, a sputtering device equipped with the thin film formation device described in Patent Document 4 can be used.

[0073] A specific example of a manufacturing apparatus that can be used in the method for manufacturing the optical laminate of this embodiment is a manufacturing apparatus 20 shown in FIG. The manufacturing apparatus 20 shown in Figure 4 includes a roll unwinding device 4, a preprocessing device 2A, a sputtering device 1, a preprocessing device 2B, a vapor deposition device 3, and a roll winding device 5. As shown in Figure 4, these devices 4, 2A, 1, 2B, 3, and 5 are connected in this order. The manufacturing apparatus 20 shown in Figure 4 is a roll-to-roll type manufacturing apparatus that unwinds a substrate from a roll, passes the substrate through connected devices in succession (preprocessing device 2A, sputtering device 1, preprocessing device 2B, and vapor deposition device 3 in Figure 4), and then winds it up, thereby continuously forming multiple layers on the substrate.

[0074] When the optical laminate 10 is produced using a roll-to-roll production device, the conveying speed (line speed) of the optical laminate 10 during production can be appropriately set. The conveying speed is, for example, preferably 0.5 to 20 m / min, and more preferably 0.5 to 10 m / min.

[0075] <Roll unwinding device> The roll unwinding device 4 shown in Fig. 4 has a chamber 34 the inside of which is kept at a predetermined reduced pressure, one or more vacuum pumps 21 (one in Fig. 4) that exhaust gas from the chamber 34 to create a reduced pressure atmosphere, and an unwinding roll 23 and a guide roll 22 installed in the chamber 34. As shown in Fig. 4, the chamber 34 is connected to the chamber 31 of the sputtering device 1 via the pretreatment device 2A. The transparent substrate 11 having the hard coat layer 12 formed on the surface thereof is wound around the unwinding roll 23. The unwinding roll 23 supplies the transparent substrate 11 having the hard coat layer 12 formed on the surface thereof to the pretreatment device 2A at a predetermined transport speed.

[0076] <Pre-treatment device 2A> Pretreatment device 2A shown in Fig. 4 has chamber 32, the interior of which is kept at a predetermined reduced pressure, can roll 26, multiple (two in Fig. 4) guide rolls 22, and plasma discharge device 42. As shown in Fig. 4, can roll 26, guide roll 22, and plasma discharge device 42 are installed in chamber 32. As shown in Fig. 4, chamber 32 is connected to chamber 31 of sputtering device 1.

[0077] The can roll 26 and the guide roll 22 transport the transparent substrate 11 on which the hard coat layer 12 has been formed, which has been sent from the roll unwinding device 4, at a predetermined transport speed, and send the transparent substrate 11 with the surface of the hard coat layer 12 treated to the sputtering device 1. As shown in Fig. 4, the plasma discharge device 42 is disposed facing the outer peripheral surface of the can roll 26 at a predetermined distance. The plasma discharge device 42 ionizes gas by glow discharge. The gas is preferably inexpensive, inert, and does not affect the optical properties, and examples of the gas that can be used include argon gas, oxygen gas, nitrogen gas, and helium gas. Argon gas is preferably used as the gas because it has a large mass, is chemically stable, and is easily available. In this embodiment, it is preferable to use a glow discharge device as the plasma discharge device 42, which ionizes argon gas with high frequency plasma.

[0078] <Sputtering equipment> The sputtering apparatus 1 shown in Fig. 4 includes a chamber 31, the interior of which is maintained at a predetermined reduced pressure, one or more vacuum pumps 21 (two in Fig. 4) that exhaust gas from the chamber 31 to create a reduced pressure atmosphere, a film-forming roll 25, a plurality of guide rolls 22 (two in Fig. 4), and a plurality of film-forming units 41 (four in the example shown in Fig. 4). As shown in Fig. 4, the film-forming roll 25, the guide roll 22, and the film-forming units 41 are installed in the chamber 31. As shown in Fig. 4, the chamber 31 is connected to a chamber 32 of a pretreatment device 2B.

[0079] The film-forming roll 25 and the guide roll 22 transport the transparent substrate 11 having the surface-treated hard coat layer 12 formed thereon, sent from the pre-treatment device 2A, at a predetermined transport speed, and supply the transparent substrate 11 having the adhesion layer 13 and the optical functional layer 14 formed on the hard coat layer 12 to the pre-treatment device 2B. In the sputtering apparatus 1 shown in Figure 4, an adhesion layer 13 is laminated by sputtering on the hard coat layer 12 of the transparent substrate 11 running on the film-forming roll 25, and high refractive index layers 14a and low refractive index layers 14b are alternately laminated on top of that to form an optically functional layer 14.

[0080] As shown in FIG. 4 , multiple film forming units 41 are disposed facing the outer circumferential surface of the film forming roll 25 at a predetermined distance, surrounding the film forming roll 25. The number of film forming units 41 is determined based on the total number of layers including the adhesive layer 13 and the high-refractive index layers 14a and low-refractive index layers 14b that form the optical functional layer 14. When the total number of layers including the adhesive layer 13 and the high-refractive index layers 14a and low-refractive index layers 14b that form the optical functional layer 14 is large, making it difficult to ensure sufficient distance between adjacent film forming units 41, multiple film forming rolls 25 may be provided within the chamber 31, and film forming units 41 may be disposed around each film forming roll 25. When multiple film forming rolls 25 are provided, additional guide rolls 22 may be installed as necessary. Multiple chambers 31 each equipped with a film forming roll 25 and a film forming unit 41 may be connected together. Furthermore, the diameter of the film forming roll 25 may be appropriately adjusted to facilitate ensuring sufficient distance between adjacent film forming units 41.

[0081] A predetermined target (not shown) is installed in each film forming unit 41. A voltage is applied to the target using a known structure. In this embodiment, a gas supply unit (not shown) that supplies a predetermined reactive gas and carrier gas to the target at a predetermined flow rate, and a known magnetic field generating source (not shown) that forms a magnetic field on the surface of the target are installed near the target.

[0082] The target material and the type and flow rate of the reactive gas are determined appropriately depending on the compositions of the adhesion layer 13, high refractive index layer 14a, and low refractive index layer 14b formed on the transparent substrate 11 by passing between the film-forming unit 41 and the film-forming roll 25. For example, when forming a layer made of SiO2, Si is used as the target and O2 is used as the reactive gas. Also, when forming a layer made of Nb2O5, Nb is used as the target and O2 is used as the reactive gas.

[0083] In this embodiment, it is preferable to use magnetron sputtering as the sputtering method from the viewpoint of increasing the film formation speed. The sputtering method is not limited to magnetron sputtering, and may be a two-pole sputtering method that uses plasma generated by DC glow discharge or high frequency, or a three-pole sputtering method that adds a hot cathode.

[0084] The sputtering apparatus 1 is equipped with an optical monitor (not shown) as a measurement unit that measures optical properties after forming each layer that will become the adhesion layer 13 and the optical functional layer 14. This makes it possible to confirm the quality of the formed adhesion layer 13 and optical functional layer 14. When the sputtering apparatus 1 has, for example, two or more chambers, it is preferable to install an optical monitor in each chamber.

[0085] An example of an optical monitor (not shown) is one that uses an optical head capable of scanning in the width direction to measure the optical properties in the width direction of the adhesion layer 13 and the optical functional layer 14 formed on the hard coat layer 12. When such an optical monitor is provided, for example, the peak wavelength of reflectance is measured as the optical property, and converted into optical thickness, thereby making it possible to measure the optical thickness distribution in the width direction of the adhesion layer 13 and the optical functional layer 14. By measuring the optical properties using the optical monitor, it is possible to form an optical laminate 10 that includes an adhesion layer 13 and an optical functional layer 14 with optimal optical properties while adjusting the sputtering conditions in real time.

[0086] <Pre-treatment device 2B> Pretreatment device 2B shown in Fig. 4 has chamber 32, the interior of which is kept at a predetermined reduced pressure, can roll 26, multiple (two in Fig. 4) guide rolls 22, and plasma discharge device 42. As shown in Fig. 4, can roll 26, guide roll 22, and plasma discharge device 42 are installed in chamber 32. As shown in Fig. 4, chamber 32 is connected to chamber 33 of vapor deposition device 3.

[0087] The can roll 26 and the guide roll 22 transport the transparent substrate 11, on which each layer up to the optical functional layer 14 has been formed, sent from the sputtering device 1, at a predetermined transport speed, and send the transparent substrate 11, on which the surface of the optical functional layer 14 has been treated, to the vapor deposition device 3. The plasma discharge device 42 may be, for example, the same as the pretreatment device 2A. The plasma discharge device 42 ionizes gas by glow discharge. The gas is preferably inexpensive, inert, and does not affect the optical properties, and examples of the gas that can be used include argon gas, oxygen gas, nitrogen gas, and helium gas. Argon gas and oxygen gas have a large effect on the surface of the optical functional layer 14. In particular, using argon gas, which has a large mass, makes it easier to adjust the surface roughness Ra or the average element length RSm of the optical functional layer 14.

[0088] <Vapor deposition equipment> The vapor deposition apparatus 3 shown in Figure 4 includes a chamber 33 the interior of which is maintained at a predetermined reduced pressure, one or more vacuum pumps 21 (one in Figure 4) that evacuate gas from the chamber 33 to create a reduced pressure atmosphere, multiple guide rolls 22 (four in Figure 4), a vapor deposition source 43, and a heating device 53. As shown in Figure 4, the guide rolls 22 and the vapor deposition source 43 are installed in the chamber 33. The chamber 33 is connected to a chamber 35 of the roll winding device 5.

[0089] The vapor deposition source 43 is disposed opposite the transparent substrate 11, on which the surface of the optical functional layer 14 has been treated, and which is being transported substantially horizontally between two adjacent guide rolls 22. The vapor deposition source 43 supplies evaporated gas made of a material that will become the antifouling layer 15 onto the optical functional layer 14. The orientation of the vapor deposition source 43 can be set as desired. The heating device 53 heats the material that will become the antifouling layer 15 to the vapor pressure temperature. The heating device 53 can be one that uses a resistance heating method, a heater heating method, an induction heating method, an electron beam heating method, or the like. In the resistance heating method, a container that contains the antifouling material that will become the antifouling layer 15 is heated by passing electricity through it as a resistor. In the heater heating method, the container is heated by a heater arranged around the periphery of the container. In the induction heating method, the container or the antifouling material is heated by electromagnetic induction from an externally installed induction coil.

[0090] The vapor deposition device 3 shown in Figure 4 is equipped with a guide plate (not shown) that guides the vapor deposition material evaporated from the vapor deposition source 43 to a predetermined position, a film thickness meter (not shown) that observes the thickness of the antifouling layer 15 formed by vapor deposition, a vacuum pressure meter (not shown) that measures the pressure inside the chamber 33, and a power supply unit (not shown). The guide plate may have any shape as long as it can guide the evaporated deposition material to a desired position. If the guide plate is not necessary, it does not have to be provided. As the vacuum pressure gauge, for example, an ion gauge can be used. The power supply device may be, for example, a high frequency power supply.

[0091] <Roll winding device> The roll winding device 5 shown in Figure 4 has a chamber 35 inside which a predetermined reduced pressure atmosphere is maintained, one or more vacuum pumps 21 (one in Figure 4) that exhaust gas from the chamber 35 to create a reduced pressure atmosphere, and a winding roll 24 and a guide roll 22 installed inside the chamber 35. The transparent substrate 11 (optical laminate 10) having each layer formed on its surface up to the antifouling layer 15 is wound around the winding roll 24. The winding roll 24 and the guide roll 22 wind up the optical laminate 10 at a predetermined winding speed. If necessary, a carrier film may also be used.

[0092] 4 may be equipped with a dry pump, an oil rotary pump, a turbomolecular pump, an oil diffusion pump, a cryopump, a sputter ion pump, a getter pump, etc. The vacuum pump 21 may be appropriately selected or used in combination to create a desired reduced pressure state in each of the chambers 31, 32, 33, 34, and 35.

[0093] The location and number of vacuum pumps 21 installed in manufacturing apparatus 20 are not particularly limited as long as they can maintain both chamber 31 of sputtering apparatus 1 and chamber 33 of vapor deposition apparatus 3 at the desired reduced pressure. In manufacturing apparatus 20 shown in FIG. 4, roll unwinding apparatus 4, preprocessing apparatus 2A, sputtering apparatus 1, preprocessing apparatus 2B, vapor deposition apparatus 3, and roll winding apparatus 5 are connected. Therefore, vacuum pumps 21 may be installed in each of chambers 31, 32, 33, 34, and 35, or may be installed in only some of chambers 31, 32, 33, 34, and 35, as long as they can maintain both chamber 31 of sputtering apparatus 1 and chamber 33 of vapor deposition apparatus 3 at the desired reduced pressure.

[0094] Next, we will explain a method of using the manufacturing apparatus 20 shown in Figure 4 to continuously perform the first surface treatment process, adhesion layer formation process, optical functional layer formation process, second surface treatment process, and anti-fouling layer formation process while maintaining the optical laminate 10 in the middle of production under reduced pressure. First, the unwinding roll 23 around which the transparent substrate 11 having the hard coat layer 12 formed on its surface is wound is placed in the chamber 34 of the roll unwinding device 4. Then, the unwinding roll 23 and the guide roll 22 are rotated to send the transparent substrate 11 having the hard coat layer 12 formed on its surface to the pretreatment device 2A at a predetermined transport speed.

[0095] Next, in the chamber 32 of the pretreatment device 2A, a first surface treatment step is performed as a pretreatment for the surface on which the adhesion layer 13 and the optical functional layer 14 are to be formed. In this embodiment, the first surface treatment step is performed on the transparent substrate 11 on which the hard coat layer 12 is formed. In the first surface treatment step, the can roll 26 and the guide roll 22 are rotated to transport the transparent substrate 11 on which the hard coat layer 12 is formed at a predetermined transport speed, while treating the surface of the hard coat layer 12 running on the can roll 26.

[0096] The surface of the hard coat layer 12 can be treated by, for example, glow discharge treatment, plasma treatment, ion etching, or alkali treatment. Among these, glow discharge treatment is preferred because it allows treatment over a large area. The glow discharge treatment can be performed at a treatment intensity of, for example, 0.1 to 10 kWh. By performing glow discharge treatment on the surface of the hard coat layer 12, the surface of the hard coat layer 12 is roughened at the nano level and substances with weak bonding strength present on the surface of the hard coat layer 12 are removed, resulting in good adhesion between the hard coat layer 12 and the optical functional layer 14 formed on the hard coat layer 12.

[0097] Next, an adhesion layer forming step and an optical function layer forming step are performed in the chamber 31 of the sputtering apparatus 1. Specifically, the film forming roll 25 and the guide roll 22 are rotated to transport the transparent substrate 11 on which the hard coat layer 12 has been formed at a predetermined transport speed, and the adhesion layer 13 and the optical function layer 14 are formed on the hard coat layer 12 running on the film forming roll 25.

[0098] In this embodiment, the adhesion layer 13 is formed by sputtering while changing the material of the target installed in each film forming unit 41 or the type and flow rate of the reactive gas supplied from the gas supply unit, and high refractive index layers 14a and low refractive index layers 14b are alternately laminated on top of the adhesion layer 13. That is, the adhesion layer formation process and the optical function layer formation process are performed consecutively within the sputtering apparatus 1. In this way, the adhesion layer 13 and the optical function layer 14, which is an anti-reflection layer, are formed.

[0099] SiO as the adhesion layer 13 x When forming the film, it is preferable to form it by reactive sputtering using a silicon target in a mixed gas atmosphere of oxygen gas and argon gas. When the adhesion layer 13, the high refractive index layer 14a, and the low refractive index layer 14b are successively laminated by sputtering, different target materials may be used for forming the adhesion layer 13, the high refractive index layer 14a, and the low refractive index layer 14b. Alternatively, for example, one type of material may be used as the target, and layers made of the target material and layers made of an oxide of the target material may be alternately formed by changing the flow rate of oxygen (reactive gas) during sputtering, to form the adhesion layer 13, the high refractive index layer 14a, and the low refractive index layer 14b.

[0100] The pressure during sputtering to form the adhesion layer 13 and the optical functional layer 14 varies depending on the metal to be sputtered, but may be 2 Pa or less, preferably 1 Pa or less, more preferably 0.6 Pa or less, and particularly preferably 0.2 Pa or less. When the pressure during sputtering is reduced to 1 Pa or less, the mean free path of the film-forming molecules becomes longer, and the film-forming molecules are deposited while maintaining high energy, resulting in a denser and better film quality.

[0101] Thereafter, the transparent substrate 11 having the adhesive layer 13 and the optical functional layer 14 formed on the hard coat layer 12 is sent to the pretreatment device 2B by the rotation of the film-forming roll 25 and the guide roll 22. Next, in the chamber 32 of the pretreatment device 2B, a second surface treatment step is carried out as a pretreatment for the surface on which the antifouling layer 15 is to be formed. In this embodiment, the second surface treatment step is carried out continuously while maintaining the transparent substrate 11 on which the optical functional layer 14 formed in the optical functional layer forming step under reduced pressure without exposing it to the air. In the second surface treatment process, the can roll 26 and the guide roll 22 are rotated to transport the transparent substrate 11, on which each layer up to the optical functional layer 14 has been formed, at a predetermined transport speed, while a discharge treatment is performed on the surface of the optical functional layer 14 running on the can roll 26.

[0102] The surface of the optical functional layer 14 can be treated by, for example, glow discharge treatment, plasma treatment, ion etching, or alkali treatment. Among these, glow discharge treatment is preferred because it allows for large-area treatment. The glow discharge treatment is preferably performed in an atmosphere of O2 gas or argon gas. Using these gases makes it easier to adjust the surface roughness of the optical functional layer 14. When the surface of the optical functional layer 14 is subjected to a discharge treatment, the surface of the optical functional layer 14 is etched, and the surface roughness of the optical functional layer 14 changes. The surface roughness Ra of the optical functional layer 14 can be controlled by setting the cumulative power during the discharge treatment within an appropriate range. The cumulative power during the discharge treatment is 130 W·min / m 2 More than 2000W min / m 2 In this embodiment, the integrated output is a value obtained by dividing the product of the glow discharge output irradiated onto the optical function layer 14 and the irradiation time during the discharge treatment by a unit area.

[0103] The conditions for the discharge treatment can be set as appropriate. By appropriately setting the conditions for the discharge treatment, the adhesion between the optical functional layer 14 and the antifouling layer 15 formed thereon can be improved, and an optical laminate 10 with even better abrasion resistance and alkali resistance can be obtained. The surface roughness Ra and average element length RSm of the optical functional layer 14 after the discharge treatment differ depending on the average length of the surface roughness elements of the hard coat layer 12 provided below the optical functional layer 14 . Furthermore, the surface roughness Ra and the average element length RSm of the optical functional layer 14 after the discharge treatment affect the surface roughness Ra and the average element length RSm of the antifouling layer 15 formed on the optical functional layer 14 .

[0104] In the second surface treatment step, the surface of the optical functional layer is treated so that the rate of change in surface roughness, expressed by the following formula (1), is 1 to 25%. The surface of the optical functional layer is treated under these conditions, particularly in the case of a clear anti-reflection film. For example, the integrated output during the discharge treatment is one of the parameters that affect the rate of change in surface roughness. Surface roughness change rate (%) = ((Ra2 / Ra1) - 1) × 100 (%) Equation (1) (In equation (1), Ra1 represents the surface roughness (Ra) of the optical functional layer before the surface treatment, and Ra2 represents the surface roughness (Ra) of the optical functional layer after the surface treatment.)

[0105] The second surface treatment step is preferably carried out so that the rate of change in surface roughness represented by formula (1) is 5% to 25%, more preferably 8% to 25%, even more preferably 8% to 20%, even more preferably 8% to 15%, and even more preferably 10% to 14%. When the rate of change in surface roughness represented by formula (1) is 1% or more, the effect of improving the adhesion between the optical functional layer 14 and the antifouling layer 15 by carrying out the second surface treatment step is significant. Furthermore, when the rate of change in surface roughness represented by formula (1) is 25% or less, the thickness of the optical functional layer 14 is appropriate, and therefore, an antifouling layer 15 with a uniform thickness is formed on the optical functional layer 14.

[0106] In the second surface treatment step, the surface of the optical functional layer is treated so that the rate of change in the average length of the elements, as expressed by the following formula (2), is 7 to 65%. In particular, the surface of the optical functional layer is treated under these conditions in the case of an AG-type antireflection film. For example, the integrated output during the discharge treatment is one of the parameters that affect the average length of the elements. Average element length change rate (%) = ((RSm2 / RSm1)-1) × 100 (%)...Equation (2) (In formula (2), RSm1 represents the average length (RSm) of the elements of the optical functional layer before surface treatment, and RSm2 represents the average length (RSm) of the elements of the optical functional layer after surface treatment.)

[0107] The second surface treatment step is preferably carried out so that the rate of change in the average length (RSm) of the elements represented by formula (2) is 11% to 62%, more preferably 11% to 45%, and even more preferably 11% to 17%. When the rate of change in the average length of the elements represented by formula (2) is within the above range, the effect of improving the adhesion between the optical functional layer 14 and the antifouling layer 15 by carrying out the second surface treatment step is significant. Furthermore, when the rate of change in the average length of the elements represented by formula (2) is a predetermined value or less, the thickness of the optical functional layer 14 is appropriate, and therefore, an antifouling layer 15 with a uniform thickness is formed on the optical functional layer 14.

[0108] In this embodiment, the surface roughness (Ra) of the optical function layer 14 can be measured by the following method: 2 The surface roughness (Ra) is measured in accordance with JIS B0601 (ISO4287). The mean element length (RSm) is measured using an atomic force microscope. 2 The average length of the elements (RSm) is also measured in accordance with JIS B0601 (ISO4287).

[0109] Thereafter, the transparent substrate 11 with the surface of the optical functional layer 14 treated is sent to the vapor deposition device 3 by the rotation of the can roll 26 and the guide roll 22 . Next, an antifouling layer forming step is carried out in the chamber 33 of the vapor deposition device 3. In this embodiment, the transparent substrate 11, whose surface has been treated with the optical functional layer 14 obtained in the second surface treatment step, is continuously subjected to the antifouling layer forming step while being maintained under reduced pressure without being exposed to the atmosphere. In the antifouling layer forming step, the guide roll 22 is rotated to transport the transparent substrate 11, whose surface has been treated with the optical functional layer 14, at a predetermined transport speed, while vapor deposition source 43 is vapor-deposited onto the surface of the optical functional layer 14.

[0110] In this embodiment, for example, an antifouling material made of a fluorine-based organic compound that will become the antifouling layer 15 is heated to a vapor pressure temperature by a heating device 53, and the resulting evaporated gas is supplied from a vapor deposition source 43 in a reduced pressure environment and attached to the optical function layer 14 whose surface has been treated, thereby forming the antifouling layer 15 by vacuum deposition. The pressure during vacuum deposition of the antifouling layer 15 is, for example, preferably 0.05 Pa or less, more preferably 0.01 Pa or less, and particularly preferably 0.001 Pa or less. When the pressure during vacuum deposition is a reduced pressure of 0.05 Pa or less, the mean free path of the film-forming molecules is long and the deposition energy is high, resulting in a denser and better antifouling layer 15.

[0111] By the above method, an optical laminate 10 is obtained in which the antifouling layer 15 is formed by vacuum deposition on the adhesion layer 13 and the optical functional layer 14 formed by sputtering.

[0112] Thereafter, the transparent substrate 11 (optical laminate 10) on which each layer up to the antifouling layer 15 has been formed is sent to the roll winding device 5 by the rotation of the guide roll 22. Then, in the chamber 35 of the roll winding device 5, the optical laminate 10 is wound around the winding roll 24 by the rotation of the winding roll 24 and the guide roll 22.

[0113] In this embodiment, it is preferable to perform the optical functional layer formation process and the antifouling layer formation process continuously under reduced pressure. In particular, when the optical laminate 10 is continuously produced as a wound body using a roll-to-roll method, as in the manufacturing method of this embodiment using the manufacturing apparatus 20 shown in FIG. 4, it is more preferable to perform the optical functional layer formation process and the antifouling layer formation process continuously in-line while maintaining a reduced pressure. "In-line" means that the antifouling layer formation process is performed without exposing the optical functional layer 14 formed in the optical functional layer formation process to the atmosphere. By performing the optical functional layer formation process and the antifouling layer formation process continuously under reduced pressure, the formation of a natural oxide film on the optical functional layer 14 formed in the optical functional layer formation process before the antifouling layer 15 is formed can be suppressed. Furthermore, contamination such as foreign matter that adheres to the optical functional layer 14 during winding of the roll can be prevented, which would inhibit the adhesion between the optical functional layer 14 and the antifouling layer 15. Therefore, compared to when, after the optical functional layer forming process, the transparent substrate 11 on which each layer up to the optical functional layer 14 has been formed is removed from the chamber under reduced pressure, and then placed back into the chamber to perform the anti-fouling layer forming process under reduced pressure, an optical laminate with good adhesion between the optical functional layer 14 and the anti-fouling layer 15 and excellent transparency can be obtained.

[0114] Furthermore, since the antifouling layer 15 of the optical laminate 10 of this embodiment is a vapor-deposited film, it has higher abrasion resistance and liquid resistance than, for example, an antifouling film formed by a coating method. This is presumably due to the following reasons. Specifically, an antifouling film formed by a coating method has voids caused by the solvent contained in the paint. In contrast, a vapor-deposited film does not have voids caused by the solvent. For this reason, it is presumed that a vapor-deposited film has a higher density and has higher abrasion resistance and alkali resistance than an antifouling film formed by a coating method.

[0115] The method for producing the optical laminate 10 of this embodiment includes an adhesion layer forming step of forming an adhesion layer 13, an optical functional layer forming step of forming an optical functional layer 14 by alternately laminating high refractive index layers 14a and low refractive index layers 14b, a second surface treatment step of treating the surface of the optical functional layer 14, and an antifouling layer forming step of forming an antifouling layer 15 on the surface-treated optical functional layer 14. This results in good adhesion between the optical functional layer 14 and the antifouling layer 15 formed on the optical functional layer 14, and further improved friction resistance and alkali resistance.

[0116] In particular, when the surface of the optical functional layer is treated in the second surface treatment step so that the rate of change in surface roughness expressed by formula (1) is 1 to 25%, the surface of the optical functional layer 14 is changed to an appropriate roughness, and the surface is activated by etching, which is preferable because it improves reactivity with the antifouling layer 15 formed on the optical functional layer 14. The same is true when the surface of the optical functional layer is treated in the second surface treatment step so that the rate of change in the average length of the elements expressed by formula (2) is 7 to 65%. Furthermore, in the manufacturing method of the optical laminate 10 of this embodiment, the optical laminate 10 can be continuously formed using a roll-to-roll method, and the film thickness can be controlled with high precision, so it is preferable to form the optical functional layer 14 by sputtering in the optical functional layer formation process.

[0117] In this embodiment, when the first surface treatment process, the optical functional layer formation process, the second surface treatment process, and the antifouling layer formation process are performed successively while maintaining the optical laminate in the middle of production under reduced pressure, the reduced pressure conditions in the chambers of, for example, the sputtering apparatus and the vapor deposition apparatus may be different, as long as they do not interfere with each production process.

[0118] In this embodiment, it is preferable to measure the film formation results over time using a measuring device in one or more of the adhesion layer formation process, optical function layer formation process, and antifouling layer formation process, and feed the results back to the conditions of the subsequent manufacturing process. This makes it easier to optimize the properties of the entire optical laminate and make the in-plane properties of the optical laminate uniform. In addition, the measuring device can also be used to feedback the manufacturing conditions in the same process. In this case, the layer formed in that process will have uniform and stable properties.

[0119] In this embodiment, the second surface treatment step is performed between the optical functional layer forming step and the antifouling layer forming step, but the second surface treatment step may be performed as needed or may not be performed. Even when the second surface treatment step is not performed, it is preferable to perform the optical functional layer forming step and the antifouling layer forming step consecutively under reduced pressure.

[0120] In this embodiment, an example has been described in which the optical laminate 10 is continuously manufactured using a roll-to-roll method using a manufacturing apparatus 20 shown in Figure 4, which is equipped with a pre-processing device 2A, a sputtering device 1, a pre-processing device 2B, a vapor deposition device 3, a roll unwinding device 4, and a roll winding device 5. However, the manufacturing apparatus for manufacturing the optical laminate 10 is not limited to the manufacturing apparatus 20 shown in Figure 4. For example, a manufacturing apparatus may be used that does not include pretreatment devices 2A and 2B, and that includes roll unwinding device 4, sputtering device 1, vapor deposition device 3, and roll winding device 5 connected in this order.

[0121] The manufacturing apparatus 20 shown in FIG. 4 may be provided with a pretreatment chamber (not shown) between the chamber 33 of the vapor deposition apparatus 3 and the chamber 32 of the pretreatment apparatus 2B for cleaning the surface of the optical functional layer 14 on which the antifouling layer 15 is to be formed. The manufacturing apparatus 20 shown in FIG. 4 may be provided with a post-treatment chamber (not shown) between the chamber 33 of the vapor deposition device 3 and the chamber 35 of the roll winding device 5 for cooling and / or inspecting the transparent substrate 11 on which each layer up to the antifouling layer 15 has been formed.

[0122] 4 may be provided with a hard coat layer forming device between the roll unwinding device 4 and the sputtering device 1 for forming a hard coat layer 12 on the surface of the transparent substrate 11. In this case, not only the optical functional layer 14 and the antifouling layer 15 but also the hard coat layer 12 can be continuously produced by the roll-to-roll method, which is preferable.

[0123] In this embodiment, an example has been described in which the optical functional layer formation process is performed using a sputtering device and the antifouling layer formation process is performed using a vapor deposition device, but if the second surface treatment process is not performed, the optical functional layer formation process and the antifouling layer formation process may be performed in the same device (within one chamber).

[0124] In the optical laminate 10 of this embodiment, various layers may be provided as needed on the surface of the transparent substrate opposite the surface on which the optical functional layer or the like is formed. For example, a pressure-sensitive adhesive layer used for bonding to other members may be provided. Furthermore, another optical film may be provided via this pressure-sensitive adhesive layer. Examples of other optical films include films that function as polarizing films, retardation compensation films, half-wave plates, and quarter-wave plates.

[0125] Furthermore, a layer having functions such as antireflection, selective reflection, antiglare, polarization, phase difference compensation, viewing angle compensation or expansion, light guiding, diffusion, brightness improvement, hue adjustment, and conductivity may be formed directly on the opposing surface of the transparent substrate. The optical laminate may have a smooth shape or a shape having a nano-order uneven structure that exhibits a moth-eye or anti-glare function. It may also have a geometric shape on the order of micro to millimeters, such as a lens or prism. The shape can be formed by, for example, a combination of photolithography and etching, shape transfer, heat pressing, or the like. In this embodiment, since the film is formed by vapor deposition or the like, even if the substrate has an uneven shape, the uneven shape can be maintained.

[0126] The article of this embodiment is, for example, a liquid crystal display panel, an organic EL display panel, or the like, in which the above-described optical laminate 10 is provided on the display surface of an image display unit. This makes it possible to impart high abrasion resistance and alkali resistance to, for example, the touch panel display unit of a smartphone or an operating device, and to realize an image display device that is excellent in durability and suitable for practical use.

[0127] Furthermore, the article is not limited to image display devices, and may be anything to which the optical laminate 10 can be applied, such as window glass or goggles having the optical laminate of this embodiment provided on the surface, the light receiving surface of a solar cell, a smartphone screen or a personal computer display, an information input terminal, a tablet terminal, an AR (augmented reality) device, a VR (virtual reality) device, an electronic display board, the surface of a glass table, an amusement machine, operation support devices for aircraft and trains, navigation systems, instrument panels, the surface of an optical sensor, or the like.

[0128] Although the embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. For example, instead of the hard coat layer 12, an anti-glare layer may be formed, or an arbitrary functional layer such as a soft coat layer having flexibility may be added as needed. These may also be laminated. [Example]

[0129] The effects of the present invention were verified. The optical laminates produced in the following Examples and Comparative Examples are merely examples that function as anti-reflection films, and the scope of the present invention is not limited to these.

[0130] (Examples 1 to 5, Comparative Examples 2 and 4) First, a photocurable resin composition was prepared, containing 28 mass% of silica particles (filler) with an average particle size of 50 nm relative to the total solid content of the resin composition (binder resin). The resin composition was prepared by dissolving silica particles, acrylate, a leveling agent, and a photopolymerization initiator in a solvent, as shown in Table 1.

[0131] [Table 1]

[0132] SR610: Polyethylene glycol diacrylate, average molecular weight of polyethylene glycol chain: 600 CN968: Hexafunctional aliphatic urethane acrylate with polyester backbone Irgacure 184: 1-Hydroxy-cyclohexyl-phenyl-ketone

[0133] <Hard Coat Layer Forming Process> A roll of TAC film having a thickness of 80 μm and a length of 3,900 m was prepared as the transparent substrate 11, and the photocurable resin composition shown in Table 1 was applied onto the TAC film using a gravure coater, and then cured by irradiating with light to form a hard coat layer 12 having a thickness of 5 μm.

[0134] Next, using the roll-to-roll method, an adhesion layer 13, an optical functional layer 14, and an antifouling layer 15 were continuously produced in this order on the transparent substrate 11 on which the hard coat layer 12 was formed, by the method described below, to produce optical laminates (anti-reflection films) of Examples 1 to 5, Comparative Example 2, and Comparative Example 4. The manufacturing apparatus used was the manufacturing apparatus 20 shown in Fig. 4. The line speed was 2 m / min. The first surface treatment step, the adhesion layer forming step, the optical functional layer forming step, the second surface treatment step, and the antifouling layer forming step were continuously performed while the optical laminate in the middle of production was maintained under reduced pressure.

[0135] <First surface treatment process> Next, the treatment intensity of the glow discharge treatment on the hard coat layer 12 was set to 4000 W·min / m 2Then, a glow discharge treatment was carried out.

[0136] <Adhesion layer forming process and optical function layer forming process> On the hard coat layer 12 after the glow discharge treatment, an adhesion layer 13 made of SiOx and having a thickness of 5 nm was formed by sputtering in a chamber with a pressure of 1.0 Pa or less, and an optical function layer 14 (laminate) made of a 15 nm thick Nb2O5 film (high refractive index layer), a 38 nm thick SiO2 film (low refractive index layer), a 30 nm thick Nb2O5 film (high refractive index layer), and a 102 nm thick SiO2 film (low refractive index layer) was formed on the adhesion layer.

[0137] <Second surface treatment process> Glow discharge treatment was performed on the surface of the optical functional layer 14. The glow discharge was performed by first reducing the pressure in the chamber to 2×10 -5 After the pressure was adjusted to 0.4 Pa, argon gas was introduced into the chamber from the linear ion source at 800 sccm, and the pressure inside the chamber was adjusted to 0.4 Pa. The integrated output of the glow discharge was adjusted by the voltage, current, and treatment time of the glow discharge.

[0138] For Examples 1 to 3, the cumulative output power of the glow discharge treatment was 326 W·min / m 2 It was decided. For Example 4, the cumulative output power of the glow discharge treatment was 760 W·min / m 2 It was decided. For Example 5, the cumulative output power of the glow discharge treatment was 1086 W·min / m 2 It was decided. For Comparative Example 2, the cumulative output power of the glow discharge treatment was 3260 W·min / m 2 It was decided. For Comparative Example 4, the cumulative output of the glow discharge treatment was 109 W·min / m 2 It was decided.

[0139] Table 2 also shows the rate of change in surface roughness expressed by the following formula (1). Surface roughness change rate (%) = ((Ra2 / Ra1) - 1) × 100 (%) Equation (1) (In equation (1), Ra1 represents the surface roughness (Ra) of the optical functional layer before the surface treatment, and Ra2 represents the surface roughness (Ra) of the optical functional layer after the surface treatment.)

[0140] <Anti-fouling layer formation process> Next, an antifouling layer 15 made of an alkoxysilane compound having a perfluoropolyether group (KY-1901, manufactured by Shin-Etsu Chemical Co., Ltd.), which is an organic compound having fluorine, was formed on the optical functional layer 14 by vapor deposition at a vapor deposition chamber pressure of 0.01 Pa or less, a vapor deposition temperature of 230°C, and a line speed of 2.0 m / min. The optical film thickness of the obtained antifouling layer 15 is shown in Table 2. Thereafter, the film was wound into a roll to obtain optical laminates (anti-reflection films) of Examples 1 to 5 and Comparative Examples 2 and 4.

[0141] [Table 2]

[0142] (Comparative Example 1) An optical laminate (anti-reflection film) of Comparative Example 1 was produced in the same manner as in Example 1, except that after the optical functional layer formation process was performed in the same manner as in Example 1, the anti-fouling layer formation process was performed without performing the second surface treatment process, and an anti-fouling layer 15 was formed on the optical functional layer 14.

[0143] (Comparative Example 3) After the optical functional layer formation step was carried out in the same manner as in Example 1, the TAC film on which the hard coat layer 12, the adhesive layer 13, and the optical functional layer 14 were formed was wound up and removed from the manufacturing apparatus, and placed in a roll-to-roll coating apparatus (coater). Thereafter, under atmospheric pressure, the TAC film on which the hard coat layer 12, the adhesive layer 13, and the optical functional layer 14 were formed was unwound, and an antifouling agent was applied onto the SiO film (low refractive index layer) of the optical functional layer 14 using a gravure coater at a line speed of 20 m / min.

[0144] The antifouling agent used was an alkoxysilane compound having a perfluoropolyether group (KY-1901, manufactured by Shin-Etsu Chemical Co., Ltd.) diluted to a concentration of 0.1% by mass using a fluorine solvent (Fluorinert FC-3283, manufactured by 3M Japan Ltd.) The antifouling agent was applied so that the thickness after drying would be as shown in Table 2.

[0145] The surface roughness Ra of the antifouling layer of each of the obtained optical laminates (antireflection films) of Examples 1 to 5 and Comparative Examples 1 to 4 was measured by the method described below. The results are shown in Table 2.

[0146] (Measurement of surface roughness Ra of antifouling layer) A measurement sample of 50 mm × 50 mm was cut out from the center of the length direction and the center of the width direction of each roll of the optical laminate wound up. The surface of the sample was observed using an atomic force microscope (AFM) (product name SPA400, NanoNavi II; manufactured by Hitachi, Ltd.), and an area of ​​1 μm 2 The surface roughness Ra was measured in the range of 1. The measurement was carried out at three points on the sample, and the average value was taken as the measured value.

[0147] The surface roughness Ra of the antifouling layer is affected by the surface roughness Ra of the underlying optical functional layer. In particular, an antifouling layer formed by vapor deposition does not have voids due to the solvent contained in the paint, as is the case with antifouling layers formed by coating methods, and is formed at a high density. Therefore, the surface roughness Ra of the underlying optical functional layer is more significantly affected than that of antifouling layers formed by coating methods. The surface roughness of the optical functional layer increases with glow discharge treatment, which in turn increases the surface roughness of the antifouling layer. Furthermore, when the optical functional layer is exposed to the atmosphere, a natural oxide film forms on the optical functional layer, reducing the surface roughening effect of the glow discharge treatment. However, when the optical functional layer and the antifouling layer are formed without exposure to the atmosphere, there is no such effect. Furthermore, the difference in surface roughness between Example 1 and Comparative Example 1 is due to the presence or absence of glow discharge treatment.

[0148] (Examples 6 to 8, Comparative Examples 5 to 8) Examples 6 to 8 and Comparative Examples 5 to 8 differ from Examples 1 to 5 and Comparative Examples 1 to 3 in that the hard coat structure was changed. In Examples 6 to 8 and Comparative Examples 5 to 8, the hard coat layer-forming step was not performed, and a commercially available film (manufactured by Dai Nippon Printing Co., Ltd.) was used. The hard coat layer was a cured product of an acrylic resin composition containing a filler with an average particle size of 2 μm. The hard coat layer had a thickness of 3 μm. The hard coat layer was laminated on a TAC (transparent substrate) with a thickness of 80 μm. In Examples 6 to 8 and Comparative Examples 5 and 6, the hard coat layer was subjected to a first surface treatment step, an adhesion layer-forming step, an optical function layer-forming step, a second surface treatment step, and an antifouling layer-forming step, in that order. In Comparative Example 7, the second surface treatment step was not performed. In Comparative Example 8, the second surface treatment step was not performed, and an antifouling layer was formed by a coating method similar to Comparative Example 3.

[0149] The integrated output for each example in which glow discharge treatment was performed in the second surface treatment step is as follows. For Examples 6 and 8, the cumulative output power of the glow discharge treatment was 1086 W·min / m 2 It was decided. For Example 7, the cumulative output power of the glow discharge treatment was 1629 W·min / m 2 It was decided. For Comparative Example 5, the cumulative output power of the glow discharge treatment was 3260 W·min / m 2 It was decided. For Comparative Example 6, the cumulative output of the glow discharge treatment was 109 W·min / m 2 It was decided.

[0150] In addition, in these Examples and Comparative Examples, the rate of change in the average length of the elements, expressed by the following formula (2), was measured. Rate of change in average element length (%)=((RSm2 / RSm1)-1)×100(%) Equation (2) (In Equation (2), RSm1 represents the average element length (RSm) of the optical functional layer before surface treatment, and RSm2 represents the average element length (RSm) of the optical functional layer after surface treatment.)

[0151] (Measurement of the average length RSm of the elements of the antifouling layer) A 50 mm x 50 mm measurement sample was cut out from the center of the length direction and the center of the width direction of each roll of the optical laminate. The surface of the sample was measured using an atomic force microscope (AFM) (product name SPA400, NanoNavi II; manufactured by Hitachi, Ltd.), and three straight lines in a top view that were not affected by the filler contained in the hard coat layer to exhibit the anti-glare function were selected. An area of ​​0.5 μm was calculated from the actual unevenness of the three straight lines. 2 The average element length RSm in the range was calculated as the average value. The results of these examples are summarized in Table 3.

[0152] [Table 3]

[0153] (Examples 9 to 12, Comparative Examples 9 to 12) Examples 9 to 12 and Comparative Examples 9 to 12 differ from Examples 1 to 5 and Comparative Examples 1 to 3 in that the hard coat structure was changed. In Examples 9 to 12 and Comparative Examples 9 to 12, the hard coat layer-forming step was not performed, and a commercially available film (manufactured by Dai Nippon Printing Co., Ltd.) was used. The hard coat layer was a cured product of an acrylic resin composition containing a filler with an average particle size of 2 μm. The hard coat layer had a thickness of 5 μm. The hard coat layer was laminated on a 60 μm-thick TAC (transparent substrate). In Examples 9 to 12 and Comparative Examples 9 and 10, the hard coat layer was subjected to a first surface treatment step, an adhesion layer-forming step, an optical function layer-forming step, a second surface treatment step, and an antifouling layer-forming step, in that order. In Comparative Example 11, the second surface treatment step was not performed. In Comparative Example 12, the second surface treatment step was not performed, and an antifouling layer was formed by a coating method similar to Comparative Example 3.

[0154] The integrated output for each example in which glow discharge treatment was performed in the second surface treatment step is as follows. For Examples 9 and 12, the cumulative output power of the glow discharge treatment was 1086 W·min / m 2 It was decided. For Example 10, the cumulative output power of the glow discharge treatment was 1629 W·min / m2 It was decided. For Example 11, the cumulative output of the glow discharge treatment was 543 W·min / m 2 It was decided. For Comparative Example 9, the cumulative output power of the glow discharge treatment was 3260 W·min / m 2 It was decided. For Comparative Example 10, the cumulative output of the glow discharge treatment was 109 W·min / m 2 It was decided. The results of these examples are summarized in Table 4.

[0155] [Table 4]

[0156] The properties of the optical laminates (anti-reflection films) of the above examples and comparative examples were also investigated. The results are shown in the table below. The test pieces used for measuring the properties were cut from approximately the center of the roll of the optical laminate in the longitudinal direction.

[0157] [Table 5]

[0158] [Table 6]

[0159] [Table 7]

[0160] [Table 8]

[0161] [Table 9]

[0162] [Table 10]

[0163] (1) Contact angle (anti-fouling properties) (1-1) Contact angle measurement test for pure water Measurement was performed using an automatic contact angle meter DM-700 (manufactured by Kyowa Interface Science Co., Ltd.) by the ellipse fitting method under the following conditions: Distilled water was placed in a glass syringe, a stainless steel needle was attached to the tip, and pure water was dropped onto the optical laminate (test piece). Amount of pure water dropped: 2.0 μL Measurement temperature: 25℃ Pure water was dropped, and the contact angle was measured at any six points on the surface of the test piece four seconds later, and the average value was taken as the pure water contact angle.

[0164] (1-2) Contact angle measurement test for oleic acid, n-hexadecane, and diiodomethane (reagents) Measurements were made using a fully automatic contact angle meter DM-700 (manufactured by Kyowa Interface Science Co., Ltd.) by the ellipse fitting method under the following conditions: Each of the above reagents was placed in a glass syringe, a stainless steel needle was attached to the tip, and each reagent was dropped onto the optical laminate (test piece). Drop volume of each reagent: 2.0 μL Measurement temperature: 25℃ The contact angles were measured at 10 random locations on the test piece surface 4 seconds after each reagent was dropped, and the average values ​​were used as the contact angles for oleic acid, n-hexadecane, and diiodomethane.

[0165] (2) Fluoride content measurement test The amount of fluorine (cps: counts per unit time) of the optical laminate (test piece) was measured (amount of fluorine before cleaning (amount of fluorine in the initial state)).

[0166] The fluorine content was measured using an X-ray photoelectron spectroscopy for chemical analysis (ESCA) (PHI5000 VersaProb*eIII, ULVAC-PHI, Inc.) and X-ray fluorescence analysis (XRF) (EDX-8000, Shimadzu Corporation). The fluorine value (cps) determined by X-ray photoelectron spectroscopy and X-ray fluorescence analysis was the average value calculated from the results of measurements of n = 3 for the initial state and n = 15 after the alkali resistance test.

[0167] (3) Alkali resistance test The optical properties of the optical laminate (test piece) were measured (sample before treatment). Next, a 0.1 mol / L aqueous sodium hydroxide solution (reagent) was prepared. A cylindrical member with an inner diameter of 38 mm was then attached to the optical laminate (test piece), the reagent was dropped into it, and the upper opening was covered with a glass plate. After leaving it at a liquid temperature of 55°C for 4 hours, each test piece was washed with distilled water to obtain a post-treatment sample.

[0168] (3-1) Optical property measurement (hue change) The backsides of the above-mentioned untreated and treated samples were attached to a black acrylic plate with transparent tape to eliminate backside reflection, and the optical properties were then measured. For optical measurements, an integrating sphere spectrophotometer (SP-64: manufactured by X-rite Co., Ltd.) was used. The settings were a D65 light source and a 10° angle, and the ΔE value, which is the amount of change in the L*a*b* (based on CIE 1976) values ​​shown in formula (2) above, was calculated using SCI (Specular Component Include, a method for measuring reflected color that takes specular reflection into account) for the unprocessed and processed samples. (3-2) Fluoride Residual Amount Measurement Test Using Alkaline Solution In the same manner as in the above-mentioned test (2), the amount of fluorine (cps) in the sample after treatment with the alkaline solution was measured using ESCA or XRF, and the residual rate (%) of fluorine in the sample after treatment was calculated.

[0169] (4) Scratch test using steel wool Using a friction tester type I conforming to JIS L0849, the friction body was moved back and forth horizontally along the surface of the optical laminate (test piece) to obtain a test piece. Steel wool (#0000 manufactured by Bonstar Co., Ltd.) was used as the friction material. The test settings were a load of 1000 g / cm 2 The stroke was 75 mm and the speed was 7 mm / s. The table shows the number of horizontal reciprocations of the friction body.

[0170] (4-1) Contact angle In the same manner as in the test (1-1) above, the contact angle of the test piece after rubbing was measured, and the difference in contact angle between the test piece before rubbing and the test piece after 500 horizontal reciprocating movements (100 horizontal reciprocating movements for Examples 6 to 12 and Comparative Examples 5 to 12) was determined. The test was carried out within 30 minutes after rubbing. (4-2) Optical property measurement (hue change) In the same manner as in the test (3-1) described above, the ΔL by SCI of the test piece before and after 500 horizontal reciprocating movements (100 horizontal reciprocating movements in Examples 6 to 12 and Comparative Examples 5 to 12) was measured. * a * b * The ΔE value, which is the amount of change in value, was calculated. In addition, similarly to the test (3-1) described above, the L value shown by the above formula (3) was measured by SCE (Specular Component Exclude, a measurement method of reflected color that does not take regular reflection light into consideration) of the test piece before rubbing and after 500 horizontal reciprocating movements (100 horizontal reciprocating movements in Examples 6 to 12 and Comparative Examples 5 to 12). * a * b * The ΔE value, which is the amount of change in value, was calculated.

[0171] (5) Scratch test using a rag (non-woven fabric wiper) The scratch test was carried out in the same manner as the scratch test using steel wool, except that a rag (nonwoven fabric wiper) (Bencotto Lint Free CT-8, manufactured by Asahi Kasei Corporation) was used as the friction body. The test settings were a load of 250 g / cm. 2The stroke was 25 mm and the speed was 50 mm / s. The table shows the number of horizontal reciprocating movements of the friction body. (5-1) Contact angle The contact angle of the test piece after rubbing was measured in the same manner as in the test (1-1) above, and the difference in the contact angle between the test piece before rubbing and the test piece after rubbing with 4000 horizontal reciprocating movements was calculated. The test was carried out within 30 minutes after rubbing.

[0172] (5-2) Fluoride Residual Amount Measurement Test In the same manner as in the test (2) above, the amount of fluorine (cps) in the treated sample was measured after 4000 horizontal reciprocating movements using a cloth using ESCA, and the remaining fluorine rate (%) in the treated sample was calculated.

[0173] (6) Ultrasonic cleaning test A fluorine-based solvent (Fluorinert FC-3283, manufactured by 3M Japan Ltd.) was placed in a container, and the optical laminate (test piece) was immersed. Ultrasonic waves were applied at 40 kHz and 240 W for 10 minutes using an ultrasonic cleaner (USK-5R, manufactured by AS ONE Corporation). The test piece was then rinsed using the fluorine-based solvent. The fluorine content (cps) of the sample after ultrasonic cleaning was measured using XRF, and the residual fluorine rate (%) of the sample after cleaning was calculated.

[0174] As shown in Tables 2 to 4, the optical laminates of Examples 1 to 5, which underwent a surface treatment process for treating the surface of the optical functional layer 14 and an antifouling layer formation process for forming an antifouling layer 15 on the surface-treated optical functional layer 14, had a higher fluorine residual rate in the alkali resistance test and a small hue change ΔE of 5 or less, compared to Comparative Example 1, which did not undergo the surface treatment process, and were therefore confirmed to have good alkali resistance. Furthermore, the optical laminates of Examples 1 to 5 had a small contact angle difference of 14 or less in an abrasion test using a waste cloth (nonwoven fabric wiper) and a high residual fluorine rate compared to Comparative Examples 1 and 2. Compared with Comparative Examples 1 and 2, the optical layered bodies of Examples 1 to 5 showed less change in hue in the alkali resistance test and had a higher residual fluorine rate.

[0175] Compared with Comparative Example 3, the optical laminates of Examples 1 to 5 had a small contact angle difference of 14 or less in an abrasion test using a rag (nonwoven fabric wiper), a small hue change in an alkali resistance test, and a high residual fluorine rate. [Explanation of symbols]

[0176] 10, 101, 102...optical laminate 11...Transparent base material 12...Hard coat layer 13...Adhesion layer 14...Optical functional layer 14a...High refractive index layer 14b...Low refractive index layer 15...Anti-fouling layer 20…Manufacturing equipment 1...Sputtering equipment 2A, 2B...Pretreatment equipment 3...Vapor deposition equipment 4...Roll unwinding device 5...Roll winding device 20…Manufacturing equipment 21...Vacuum pump 22...Guide roll 23...Unwinding roll 24...Take-up roll 25...Deposition roll 26...Can Roll 31, 32, 33, 34, 35…Chambers 41...Film forming section 42...Plasma discharge device 43...evaporation source 53...Heating device

Claims

1. A method for producing an optical laminate in which a transparent substrate, a hard coat layer, an adhesive layer, an optical functional layer, and an antifouling layer are laminated in this order, comprising: a hard coat layer forming step of forming a hard coat layer; an adhesion layer forming step of forming an adhesion layer; an optical function layer forming step of forming an optical function layer; a surface treatment step of glow discharge treating the surface of the optical functional layer; an antifouling layer forming step of forming an antifouling layer on the surface-treated optical functional layer, the hard coat layer is made of a cured product of a curable resin composition containing a binder resin and silica particles having an average particle diameter of 100 nm or less, the antifouling layer is made of a vapor-deposited film formed by vapor-depositing an alkoxysilane compound having a perfluoropolyether group, The thickness of the adhesion layer is 1 nm or more and 10 nm or less, the optical functional layer is a laminate in which low refractive index layers and high refractive index layers are alternately laminated, the thickness of the low refractive index layer is 1 nm or more and 200 nm or less, the antifouling layer has a thickness of 3 nm or more and 10 nm or less and a surface roughness Ra of 3 nm or more and 9 nm or less; The adhesion layer forming step, the optical functional layer forming step, the surface treatment step, and the antifouling layer forming step are carried out under reduced pressure, The cumulative power of the glow discharge treatment was 130 W·min / m ２ More than 760W・min / m ２ The following is a method for producing an optical laminate.

2. The method for producing an optical laminate according to claim 1 , wherein in the adhesive layer forming step and the optical function layer forming step, the adhesive layer and the optical function layer are formed by sputtering.

3. The method for producing an optical laminate according to claim 1 , wherein the antifouling layer is formed by vacuum deposition in the antifouling layer forming step.

4. The method for producing an optical laminate according to any one of claims 1 to 3, wherein the optical functional layer includes any one selected from an antireflection layer and a selective reflection layer.

5. The method for producing an optical laminate according to any one of claims 1 to 4, wherein the surface of the low refractive index layer is treated in the surface treatment step.

6. The method for producing an optical laminate according to any one of claims 1 to 5, wherein the low refractive index layer contains a metal oxide.

7. The method for producing an optical laminate according to any one of claims 1 to 6, wherein the adhesion layer contains a metal or a metal oxide.

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