Optical film, method for manufacturing optical film, optical member, and image display device

Abstract

Provided are an optical film capable of inhibiting or preventing display characteristic deterioration, a method for manufacturing an optical film, an optical member, and an image display device. An optical film (10) characterized by having a resin layer (B) (12) formed on a light-transmissive substrate (A) (11), and an element constituting the resin layer (B) (12) containing silicon, and in the resin layer (B) (12), the number of atoms at a depth of 1 nm from a surface on the opposite side to the light-transmissive substrate (A) (10) satisfies the following mathematical expression (1). 5.0 ≤ [(n Si / n total ) × 100] ≤ 9.0 (1). In the mathematical expression (1), n total is the total number of atoms of carbon, nitrogen, oxygen, and silicon, and n Si is the number of silicon atoms.

Description

Technical Field

[0001] This invention relates to optical thin films, methods for manufacturing optical thin films, optical components, and image display devices. Background Technology

[0002] Optical films used in image display devices and the like can be of the type in which a resin layer, such as a hard coating, is formed on a light-transmitting substrate (Patent Document 1, etc.). In addition, other layers are sometimes further attached to the resin layer.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-221746 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In order to make devices such as image display devices thinner, the optical films used therein are preferably made as thin as possible.

[0008] However, for the aforementioned optical films, if the thickness of the resin layer formed on the light-transmitting substrate is reduced, there is a concern that display performance defects known as pinholes (Japanese: ハジキ) may occur. On the other hand, if the amount of additives in the resin layer is increased to prevent pinholes, there is a concern that display performance defects may still occur due to contamination or peeling when other layers are attached to the resin layer.

[0009] Therefore, the object of the present invention is to provide an optical thin film that can suppress or prevent poor display characteristics, a method for manufacturing an optical thin film, an optical component, and an image display device.

[0010] Solution for solving the problem

[0011] To achieve the above objectives, the optical film of the present invention is characterized in that a resin layer (B) is formed on a light-transmitting substrate (A).

[0012] The elements constituting the resin layer (B) mentioned above include silicon.

[0013] In the resin layer (B) described above, the number of atoms at a depth of 1 nm from the surface opposite to the light-transmitting substrate (A) described above satisfies the following mathematical formula (1).

[0014] 5.0≤[(n Si / n total [1] ≤ 9.0

[0015] In the above mathematical formula (1), n totaln is the total number of atoms of carbon, nitrogen, oxygen, and silicon. Si This represents the number of silicon atoms.

[0016] A method for manufacturing the optical thin film of the present invention, characterized in that the method includes a resin layer (B) forming step in which the resin layer (B) is formed on the light-transmitting substrate (A) in a manner satisfying the mathematical formula (1).

[0017] The resin layer (B) forming process includes: a coating process of coating a resin layer forming coating liquid onto the light-transmitting substrate (A); and a coating film forming process of drying the coated resin layer forming coating liquid to form a coating film.

[0018] The coating liquid for forming the resin layer contains resin, silicon-containing additives, and diluent.

[0019] The optical component of the present invention is an optical component comprising the optical thin film of the present invention.

[0020] The image display device of the present invention is an image display device that includes the optical thin film of the present invention or the optical component of the present invention.

[0021] The effects of the invention

[0022] According to the present invention, an optical thin film capable of suppressing or preventing poor display characteristics, a method for manufacturing the optical thin film, an optical component, and an image display device can be provided. Attached Figure Description

[0023] Figure 1 A cross-sectional view illustrating an example of the optical thin film and its manufacturing method according to the present invention.

[0024] Figure 2 A cross-sectional view illustrating another example of the optical thin film of the present invention.

[0025] Explanation of reference numerals in the attached figures

[0026] 10' Optical Thin Film

[0027] 11. Translucent substrate (A)

[0028] 12. Resin layer (B)

[0029] 12a Resin layer forms resin

[0030] 12b particles

[0031] 12c thixotropic agent

[0032] 13 Adhesive layer

[0033] 20 Other Layers (C) Detailed Implementation

[0034] Next, examples will be given to further illustrate the invention. However, the invention is not limited by the following description.

[0035] In the optical thin film of the present invention, for example, the thickness of the above-mentioned resin layer (B) can be 1.0 to 5.0 μm.

[0036] In the optical thin film of the present invention, for example, the resin layer (B) described above may contain a surface modifier and the element constituting the surface modifier may contain silicon.

[0037] In the optical thin film of the present invention, for example, the surface conditioning agent described above may contain a silicon compound having a dimethylsiloxane backbone.

[0038] In the optical thin film of the present invention, for example, the resin layer (B) described above can be formed from a copolymer of oligomers having functional groups and monomers.

[0039] In the optical thin film of the present invention, for example, the resin layer (B) described above can be a hard coating.

[0040] In the optical film of the present invention, for example, on the surface of the resin layer (B) opposite to the light-transmitting substrate (A), other layers (C) may be attached by means of an adhesive layer.

[0041] In the optical thin film of the present invention, for example, the adhesive layer described above can satisfy the conditions of the following mathematical formula (2). It should be noted that the method for measuring the water contact angles d1 and d2 in the following mathematical formula (2) is not particularly limited, for example, it can be measured by the method described in the embodiments described later.

[0042] (d1-d2) / d1≥0.10 (2)

[0043] In the above mathematical formula (2), d1 is the water contact angle (°) of the surface of the resin layer (B) when the adhesive layer and the other layers (C) are not present on the surface of the resin layer (B), and d2 is the water contact angle (°) of the surface of the adhesive layer after the other layers (C) are peeled off from the adhesive layer. It should be noted that the above mathematical formula (2) has the same meaning as d2 being less than 90% of d1 (reduced by more than 10%).

[0044] In the optical thin film of the present invention, for example, the other layers (C) described above can be glass or resin films.

[0045] In the method for manufacturing the optical thin film of the present invention, for example, the resin layer (B) forming step may further include a curing step for curing the coating film.

[0046] In the method for manufacturing the optical thin film of the present invention, for example, the resin layer (B) in the optical thin film contains a surface modifier, the element constituting the surface modifier includes silicon, and the silicon-containing additive may be the surface modifier. The surface modifier may, for example, contain a silicon compound having a dimethylsiloxane backbone, as described above.

[0047] In the method for manufacturing the optical thin film of the present invention, for example, the diluent may contain MIBK (methyl isobutyl ketone) and cyclopentanone.

[0048] The optical components of the present invention may be, for example, polarizing plates.

[0049] It should be noted that in this invention, "weight" and "mass" can be used interchangeably unless otherwise stated. For example, "parts by mass" can be replaced with "parts by weight", "parts by weight" can be replaced with "parts by mass", "mass%" can be replaced with "weight%", and "weight%" can be replaced with "mass%".

[0050] [1. Optical Thin Films]

[0051] As described above, the optical thin film of the present invention is characterized in that a resin layer (B) is formed on a light-transmitting substrate (A).

[0052] The elements constituting the resin layer (B) mentioned above include silicon.

[0053] In the resin layer (B) described above, the number of atoms at a depth of 1 nm from the surface opposite to the light-transmitting substrate (A) described above satisfies the following mathematical formula (1).

[0054] 5.0≤[(n Si / n total [1] ≤ 9.0

[0055] In the above mathematical formula (1), n total n is the total number of atoms of carbon, nitrogen, oxygen, and silicon. Si This represents the number of silicon atoms.

[0056] Figure 1 An example of the optical thin film and its manufacturing method of the present invention is shown. First, as... Figure 1 As shown in (a), a light-transmitting substrate (A) 11 is prepared. Next, as... Figure 1 As shown in (b), a resin layer (B) 12 is formed on one surface of the light-transmitting substrate (A) 11. The number of atoms in the resin layer (B) 12 at a depth of 1 nm from the surface of the light-transmitting substrate (A) 11 on the opposite side satisfies the above mathematical formula (1). This operation enables the manufacture of... Figure 1The optical thin film 10 of the present invention is shown in (b). It should be noted that the manufacturing method of the optical thin film of the present invention will be described in detail below.

[0057] Alternatively, it can be like Figure 1 As shown in (c), other layers (C) 20 are then attached to the surface of the resin layer (B) 12 opposite to the light-transmitting substrate (A) 11 using an adhesive layer 13, thereby forming the optical film 10' of the present invention containing other layers (C) 20.

[0058] in addition, Figure 2 The cross-sectional view shows another example of the optical film of the present invention. As shown, the optical film 10 has a resin layer (B) 12 laminated on one side of a light-transmitting substrate (A) 11. Figure 2 In the optical thin film 10, the resin layer (B) 12 is an anti-glare hard coating. The anti-glare hard coating (B) 12 is formed in the resin layer. The resin 12a contains particles 12b and a thixotropic agent 12c.

[0059] It should be noted that in this invention, the resin layer (B) may be formed solely of resin, or it may contain other components. These other components are not particularly limited and may be one or more, for example, such as... Figure 2 As shown, it can be particles, thixotropic agents, etc.

[0060] Furthermore, the surface of the resin layer (B) opposite to the light-transmitting substrate (A) can be flat, for example, it can be as follows: Figure 2 As shown, it has unevenness. It should be noted that, in this invention, the "depth" of the surface opposite to the light-transmitting substrate (A) from the resin layer (B) is the depth in a direction perpendicular to the surface of the light-transmitting substrate (A), whether the surface is flat or uneven.

[0061] As described above, in the resin layer (B) of the optical thin film of the present invention, the number of atoms at a depth of 1 nm from the surface opposite to the light-transmitting substrate (A) satisfies the above mathematical formula (1). Satisfying the above mathematical formula (1) has the same meaning as described below: in the resin layer (B), at a depth of 1 nm from the surface opposite to the light-transmitting substrate (A), the number of silicon atoms relative to the total number of carbon, nitrogen, oxygen, and silicon atoms is 5.0% to 9.0%. At a depth of 1 nm from the surface opposite to the light-transmitting substrate (A), the number of silicon atoms relative to the total number of carbon, nitrogen, oxygen, and silicon atoms can be, for example, 5.5% or more, 6.0% or more, or 6.5% or more, or for example, 8.5% or less, 8.0% or less, or 7.5% or less.

[0062] It should be noted that the resin layer (B) described above, as defined in mathematical formula (1), must contain silicon as an element. Furthermore, the resin layer (B) may contain all three types of elements: carbon, nitrogen, and oxygen, or it may not contain all three types, or it may contain only one or two types. Additionally, the resin layer (B) may contain elements other than carbon, nitrogen, oxygen, and silicon, or it may not contain any of them.

[0063] Furthermore, the thickness of the resin layer (B) can be, for example, 1.0 to 5.0 μm as described above. The thickness of the resin layer (B) can be, for example, 1.5 μm or more, or for example, 4.5 μm or less, 4.0 μm or less, 3.5 μm or less, 3.0 μm or less, or 2.5 μm or less.

[0064] The following examples further illustrate the above-mentioned light-transmitting substrate (A), resin layer (B), adhesive layer, and other layers (C).

[0065] The aforementioned light-transmitting substrate (A) is not particularly limited, and examples include transparent plastic film substrates. The aforementioned transparent plastic film substrate is not particularly limited, but those with excellent visible light transmittance (preferably 90% or more) and excellent transparency (preferably haze value of 1% or less) are preferred. Examples include the transparent plastic film substrate described in Japanese Patent Application Publication No. 2008-90263. As the aforementioned transparent plastic film substrate, those with low optical birefringence are suitable. The optical film of the present invention can also be used as a protective film for a polarizing plate. In this case, as the aforementioned transparent plastic film substrate, films formed from cellulose triacetate (TAC), polycarbonate, acrylic polymers, polyolefins having cyclic or norbornene structures are preferred. Furthermore, in the present invention, as described later, the aforementioned transparent plastic film substrate can be the polarizing element itself. With such a configuration, a protective layer formed from TAC or the like is not required, simplifying the structure of the polarizing plate. Therefore, the number of manufacturing steps for the polarizing plate or image display device can be reduced, improving production efficiency. Furthermore, with such a configuration, the polarizing plate can be further thinned. It should be noted that when the aforementioned transparent plastic film substrate is a polarizing element, the aforementioned resin layer (B) and the other layers (C) serve as protective layers. Furthermore, with this configuration, the optical film also functions as a cover plate when mounted on, for example, the surface of a liquid crystal cell.

[0066] In this invention, the thickness of the light-transmitting substrate (A) is not particularly limited, and is, for example, in the range of 10–500 μm, 20–300 μm, or 30–200 μm, taking into account factors such as strength, processability, and thinness. The refractive index of the light-transmitting substrate (A) is not particularly limited. The refractive index is, for example, in the range of 1.30–1.80 or 1.40–1.70.

[0067] In the optical film of the present invention, for example, the resin contained in the light-transmitting substrate (A) described above may include an acrylic resin.

[0068] In the optical films of the present invention, for example, the light-transmitting substrate (A) described above can be an acrylic film.

[0069] In the optical film of the present invention, for example, the surface of the resin layer (B) opposite to the light-transmitting substrate has an unevenness, because the external haze value of the unevenness can be 5% or more. For a high anti-glare film, there is a risk of the overall appearance becoming white and blurry, and the formation of black and white patterns of varying shades. From the viewpoint of suppressing or preventing this situation, and from the viewpoint of suppressing reflected glare, it is preferable that the external haze value be as large as possible. On the other hand, from the viewpoint of suppressing or preventing the degradation of display characteristics (e.g., the image becomes unclear, the contrast in dark areas decreases, etc.), it is preferable that the external haze value is not too large. The external haze value is not particularly limited, for example, it can be 5% or more, 10% or more, 15% or more, or 20% or more, for example, it can be 50% or less, 45% or less, 40% or less, or 35% or less. In the present invention, the method for measuring the external haze value is not particularly limited, for example, it can be measured using the measurement methods described in (1) to (3) below.

[0070] (1) The total haze value of the optical thin film of the present invention was determined based on the method according to JIS K 7136.

[0071] (2) A light-transmitting adhesive is laminated onto the surface of the resin layer (B) of the optical film described in (1) opposite to the light-transmitting substrate (A), and a COP film (manufactured by Zeon Corporation, Japan, trade name ZEONOR FILM) is then attached thereon to form a laminate. When the laminate is measured using the same method as the total haze value measurement method according to JIS K 7136 (i.e., the measurement method described in (1) above), the internal haze value of the optical film described in (1) can be obtained. This internal haze value is the haze value after eliminating the influence of the unevenness of the outermost surface on the resin layer (B) side from the total haze value described in (1).

[0072] (3) The value obtained by subtracting the internal haze value measured in (2) from the total haze value measured in (1) above is taken as the external haze value of the optical film in (1) above.

[0073] In the optical film of the present invention, the resin contained in the resin layer (B) is not particularly limited, for example, it may contain acrylate resin (also known as acrylic resin).

[0074] In the optical film of the present invention, for example, the resin contained in the resin layer (B) described above may include urethane acrylate resin.

[0075] In the optical thin film of the present invention, for example as described above, the resin layer (B) can be formed from a copolymer of an oligomer having functional groups and a monomer. The oligomer having functional groups is not particularly limited, and examples include cured urethane acrylate resins. Examples of cured urethane acrylate resins include, for example, the product manufactured by Mitsubishi Chemical Corporation under the trade name "UV-1700TL". The monomer is not particularly limited, and examples include polyfunctional acrylates. Examples of polyfunctional acrylates include, for example, the product manufactured by Toa Synthetic Co., Ltd. under the trade name "M-920".

[0076] In the optical film of the present invention, for example, the resin contained in the resin layer (B) described above may be a copolymer of a cured urethane acrylate resin and a polyfunctional acrylate.

[0077] In the optical thin film of the present invention, the resin layer (B) must contain silicon as an element, as described above. Therefore, as described above, the resin layer (B) may contain a surface modifier, and the element constituting the surface modifier may include silicon. Furthermore, the surface modifier may contain a silicon compound having a dimethylsiloxane backbone. Examples of the surface modifier include leveling agents, dimethylsiloxane-modified methacrylates, polydimethylsiloxane cyclic compounds, etc. Examples of the surface modifier include "LE-303" manufactured by Kyoei Chemicals Co., Ltd., and "PC4100" manufactured by DIC Co., Ltd. The amount of the surface modifier added is not particularly limited; for example, it can be suitably set in a manner that keeps the silicon content in the resin layer (B) within the aforementioned range.

[0078] In the optical film of the present invention, the resin layer (B) is not particularly limited, and may be, for example, a hard coating, such as an anti-glare hard coating.

[0079] The optical film of the present invention can, for example, be formed by using an anti-glare hard coating forming material comprising resin and filler to form the resin layer (B), wherein the resin layer (B) has aggregated portions forming convex portions on its surface due to the aggregation of the filler. Furthermore, in the aggregated portions forming convex portions, the filler may be present in a state where multiple fillers are concentrated in one direction along the planar direction of the resin layer (B). In the image display device of the present invention, the optical film of the present invention may also be arranged such that one direction in which multiple fillers are aggregated aligns with the long side direction of the aforementioned black matrix pattern. Examples of fillers include, for example, the aforementioned particles and the aforementioned thixotropic agent.

[0080] The aforementioned resin layer (B) can be formed, for example, as follows: a coating liquid comprising resin, a silicon-containing additive, and a diluent is applied to the surface of the aforementioned translucent substrate (A) to form a coating film, as described later; then, the solvent is removed from the coating film, thereby forming the layer. Examples of the aforementioned resin include thermosetting resins and ionizing radiation-cured resins that are cured by ultraviolet light and / or light. Commercially available thermosetting resins, ultraviolet-cured resins, etc., can also be used as the aforementioned resin.

[0081] As the aforementioned thermosetting and UV-curing resins, curable compounds having at least one of acrylate and methacrylate groups that can be cured by heat, light (ultraviolet light, etc.), or electron beams can be used. Examples include oligomers or prepolymers of acrylates, methacrylates, and other polyfunctional compounds such as silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and polyols. These can be used alone or in combination of two or more.

[0082] In the above-mentioned resins, reactive diluents having at least one of acrylate and methacrylate groups can also be used. These reactive diluents can be, for example, those described in Japanese Patent Application Publication No. 2008-88309, including, for example, monofunctional acrylates, monofunctional methacrylates, polyfunctional acrylates, and polyfunctional methacrylates. As the above-mentioned reactive diluents, acrylates with three or more functions and methacrylates with three or more functions are preferred. This is because they can result in excellent hardness of the resin layer (B). Examples of the above-mentioned reactive diluents include, for example, butanediol glycerol ether diacrylate, isocyanuric acid acrylate, and isocyanuric acid methacrylate. These can be used alone or in combination of two or more.

[0083] The resin layer (B) described above may or may not contain a thixotropic agent. The thixotropic agent may be, for example, at least one selected from the group consisting of organoclay, oxidized polyolefin, and modified urea. Additionally, the thixotropic agent may be, for example, a thickener. The thixotropic agent may be used alone or in combination of two or more.

[0084] In the optical film of the present invention, the total mass of the resin forming the resin layer (B) may contain, for example, 0.2 to 5% by mass or 0.4 to 4% by mass of the thixotropic agent.

[0085] The other layers (C) mentioned above are not particularly limited, and may be, for example, a protective layer, a decorative layer, etc. The other layers (C) mentioned above may be, for example, glass or resin film (plastic film). As for the resin film mentioned above, there are no particular limitations; for example, the "E-MASK" series manufactured by Nitto Denko Corporation can be cited. The thickness of the other layers (C) mentioned above is not particularly limited; for example, it may be 10μm or more, 20μm or more, or 30μm or more, and for example, it may be 80μm or less, 70μm or less, 60μm or less, 50μm or less, or 40μm or less.

[0086] The aforementioned adhesive layer may be, for example, an adhesive layer formed by an adhesive (adhesive composition). In this invention, the aforementioned adhesive layer is preferably a layer from which the other layers (C) can be peeled off from the aforementioned resin layer (B). The thickness of the aforementioned adhesive layer is not particularly limited, and may be, for example, 5 μm or more or 10 μm or more, or may be 50 μm or less, 40 μm or less, 30 μm or less, or 20 μm or less. The aforementioned adhesive is not particularly limited, and examples include (meth)acrylic polymers. These may be dissolved or dispersed in a solvent to form a solution or dispersion and used as the aforementioned adhesive (adhesive composition). Examples of the aforementioned solvents include ethyl acetate, and only one may be used, or multiple may be used in combination. The concentration of the solute or dispersed substance (e.g., the aforementioned acrylic polymer) in the aforementioned solution or dispersion may be, for example, 10% by mass or more or 15% by mass or more, or may be 60% by mass or less, 50% by mass or less, 40% by mass or less, or 25% by mass or less. It should be noted that, in this invention, "(meth)acrylic acid polymer" refers to a polymer or copolymer of at least one monomer selected from (meth)acrylic acid, (meth)acrylate, and (meth)acrylamide. Furthermore, in this invention, "(meth)acrylic acid" means "at least one of acrylic acid and methacrylic acid," and "(meth)acrylate" means "at least one of acrylate and methacrylate." Examples of the aforementioned (meth)acrylates include, for example, straight-chain or branched alkyl esters of (meth)acrylic acid. In the aforementioned straight-chain or branched alkyl esters of (meth)acrylic acid, the number of carbon atoms in the alkyl group can be, for example, 1 or more, 2 or more, 3 or more, or 4 or more, and for example, 18 or less, 16 or less, 14 or less, 12 or less, 10 or less, or 8 or less. The aforementioned alkyl group can be substituted by one or more substituents, or it can be unsubstituted. Examples of the aforementioned substituents include hydroxyl groups, and when there are multiple substituents, they can be the same or different. Specific examples of the aforementioned (meth)acrylates include, for example, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and 4-hydroxybutyl acrylate. In addition, one type of adhesive may be used, or multiple types may be used in combination.

[0087] Furthermore, the optical film of the present invention may include, or may not include, any layers other than the light-transmitting substrate (A), the resin layer (B), the adhesive layer, and the other layers (C) described above. The aforementioned additional layers are not particularly limited; examples include easy-to-adhere layers, anti-reflective layers, and substrate layers with adhesives attached.

[0088] As described above, for optical films, if the thickness of the resin layer formed on a light-transmitting substrate is reduced, there is a concern that display characteristic defects, known as pinholes, may occur. On the other hand, if the amount of additives (such as leveling agents or other surface conditioning agents) in the resin layer is increased to prevent pinholes, there is a concern that display characteristic defects may still occur due to contamination or peeling when other layers are attached to the resin layer. In contrast, the present invention enables the resin layer (B) to satisfy the above mathematical formula (1), thereby suppressing or preventing contamination, peeling, etc., and as a result, provides an optical film that can suppress or prevent display characteristic defects.

[0089] [2. Manufacturing method of optical thin film]

[0090] The manufacturing method of the optical thin film of the present invention is not particularly limited, and it can be manufactured by any method, but preferably by the manufacturing method of the optical thin film of the present invention described above.

[0091] The manufacturing method of the aforementioned optical thin film can be carried out, for example, as described below.

[0092] First, the resin layer (B) is formed on the light-transmitting substrate (A) in a manner satisfying the mathematical formula (1) (resin layer (B) forming process). This produces a laminate of the light-transmitting substrate (A) and the resin layer (B). The resin layer (B) forming process, as described above, includes a coating process of applying a coating liquid for forming the resin layer (hereinafter sometimes simply referred to as "coating liquid" or "resin layer (B) forming material") to the light-transmitting substrate (A), and a coating film forming process of drying the applied coating liquid to form a coating film. Furthermore, as described above, the resin layer (B) forming process may further include a curing process of curing the coating film. The curing may be performed after drying, but is not limited to this. The curing may be performed by heating, light irradiation, etc. The light source is not particularly limited; for example, it may be ultraviolet light. The light source for the light irradiation is also not particularly limited; for example, it may be a high-pressure mercury lamp.

[0093] The coating liquid (resin layer (B) forming material) described above comprises the resin, the silicon-containing additive, and the diluent (hereinafter sometimes simply referred to as "solvent"). The coating liquid may or may not contain other components. These other components are not particularly limited; examples include the particles and the thixotropic agent described above.

[0094] The solvents described above are not particularly limited; various solvents can be used, either alone or in combination. To obtain the optical thin film of the present invention, the optimal solvent type and solvent ratio can be appropriately selected based on the composition of the resin, the type and content of the particles and the thixotropic agent. As solvents, there are no particular limitations, but examples include: alcohols such as methanol, ethanol, isopropanol (IPA), butanol, tert-butanol (TBA), and 2-methoxyethanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone; esters such as methyl acetate, ethyl acetate, and butyl acetate; ethers such as diisopropyl ether and propylene glycol monomethyl ether; glycols such as ethylene glycol and propylene glycol; cellosolvers such as ethyl cellosolvers and butyl cellosolvers; aliphatic hydrocarbons such as hexane, heptane, and octane; and aromatic hydrocarbons such as benzene, toluene, and xylene. Furthermore, the solvents described above may include hydrocarbon solvents and ketone solvents. For example, the hydrocarbon solvents described above may be aromatic hydrocarbons. The aforementioned aromatic hydrocarbon may be, for example, at least one selected from the group consisting of toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and benzene. The aforementioned ketone solvent may be, for example, at least one selected from the group consisting of cyclopentanone and acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, cyclohexanone, isophorone, and acetophenone. For example, to dissolve the thixotropic agent (e.g., thickener), the solvent preferably contains the aforementioned hydrocarbon solvent (e.g., toluene). The aforementioned solvent may be, for example, a solvent obtained by mixing the aforementioned hydrocarbon solvent and the aforementioned ketone solvent in a mass ratio of 90:10 to 10:90. The mass ratio of the aforementioned hydrocarbon solvent to the aforementioned ketone solvent may be, for example, 80:20 to 20:80, 70:30 to 30:70, or 40:60 to 60:40, etc. In this case, for example, the aforementioned hydrocarbon solvent may be toluene and the aforementioned ketone solvent may be methyl ethyl ketone. In addition, the solvent may contain, for example, toluene and at least one selected from the group consisting of ethyl acetate, butyl acetate, IPA, methyl isobutyl ketone, methyl ethyl ketone, methanol, ethanol and TBA.

[0095] As a transparent substrate (A), for example, when forming an intermediate layer (permeable layer) using an acrylic film, a good solvent suitable for the acrylic film (acrylic resin) can be suitably used. This solvent can be, for example, a solvent comprising a hydrocarbon solvent and a ketone solvent as described above. The hydrocarbon solvent can be, for example, an aromatic hydrocarbon. The aromatic hydrocarbon can be, for example, at least one selected from the group consisting of toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and benzene. The ketone solvent can be, for example, at least one selected from the group consisting of cyclopentanone, acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, cyclohexanone, isophorone, and acetophenone. The solvent can be, for example, a solvent obtained by mixing the hydrocarbon solvent and the ketone solvent at a mass ratio of 90:10 to 10:90. The mass ratio of the hydrocarbon solvent to the ketone solvent can be, for example, 80:20 to 20:80, 70:30 to 30:70, or 40:60 to 60:40, etc. In this case, for example, the hydrocarbon solvent could be toluene, and the ketone solvent could be methyl ethyl ketone.

[0096] When using cellulose triacetate (TAC) as the light-transmitting substrate (A), the solvent is not particularly limited, and examples include ethyl acetate, methyl ethyl ketone, MIBK (methyl isobutyl ketone), cyclopentanone, etc. Only one solvent can be used, or multiple solvents can be used in combination. In this case, the solvent can be, for example, a mixture of MIBK and cyclopentanone. The mixing ratio of MIBK and cyclopentanone is not particularly limited, and can be, for example, by mass ratio, 90:10 to 10:90, 80:20 to 20:80, or 70:30 to 30:70.

[0097] Furthermore, by appropriately selecting solvents, thixotropic properties can be well exhibited in anti-glare hard coating forming materials (coating solutions) when thixotropic agents are present. For example, when using organoclay, toluene and xylene can be used alone or in combination; when using oxidized polyolefins, methyl ethyl ketone, ethyl acetate, and propylene glycol monomethyl ether can be used alone or in combination; and when using modified urea, butyl acetate and methyl isobutyl ketone can be used alone or in combination.

[0098] Various leveling agents can be added to the resin layer (B) forming material described above. For example, fluorine-based or silicone-based leveling agents can be used to prevent uneven coating (to homogenize the coating surface). Silicone-based leveling agents can also be used to include silicon as an element in the resin layer (B). In this invention, the leveling agent can be appropriately selected based on whether the surface of the resin layer (B) requires antifouling properties or whether an antireflective layer (low refractive index layer) or a layer containing an interlayer filler is formed on the resin layer (B) as another layer (C).

[0099] The amount of the leveling agent mixed with the resin is, for example, 5 parts by weight or less, preferably in the range of 0.01 to 5 parts by weight, relative to 100 parts by weight of the resin.

[0100] In the aforementioned resin layer (B) forming material, pigments, fillers, dispersants, plasticizers, ultraviolet absorbers, surfactants, antifouling agents, antioxidants, etc., may also be added as needed, within a range that does not impair performance. These additives may be used alone, or in combination of two or more.

[0101] In the above-mentioned resin layer (B) forming material, a conventionally known photopolymerization initiator, such as that described in Japanese Patent Application Publication No. 2008-88309, can be used.

[0102] As a method for forming a coating film by coating the above-mentioned resin layer (B) forming material (coating liquid) onto the above-mentioned light-transmitting substrate (A), coating methods such as spray coating, mold coating, spray coating, gravure coating, roller coating, and bar coating can be used.

[0103] Next, as described above, the coating is dried and cured to form a resin layer (B). The drying process can be, for example, natural drying, air drying, heat drying, or a combination of these methods.

[0104] The drying temperature of the aforementioned resin layer (B) forming material (coating liquid) can, for example, be in the range of 30 to 200°C. The aforementioned drying temperature can be, for example, above 40°C, above 50°C, above 60°C, above 70°C, above 80°C, above 90°C, or above 100°C, and can be below 190°C, below 180°C, below 170°C, below 160°C, below 150°C, below 140°C, below 135°C, below 130°C, below 120°C, or below 110°C. The drying time is not particularly limited, and can, for example, be above 30 seconds, above 40 seconds, above 50 seconds, or above 60 seconds, and can be below 150 seconds, below 130 seconds, below 110 seconds, or below 90 seconds.

[0105] The curing method for the above coating is not particularly limited, but ultraviolet curing is preferred. The irradiation dose from the energy source, calculated as the cumulative exposure at an ultraviolet wavelength of 365 nm, is preferably 50–500 mJ / cm². 2 If the radiation dose is 50 mJ / cm 2 In this way, curing can proceed easily and completely, and the hardness of the resulting resin layer (B) can easily become higher. Additionally, if it is 500 mJ / cm... 2 The following can prevent the formed resin layer (B) from becoming colored.

[0106] The above-described operation can be used to manufacture a laminate of the light-transmitting substrate (A) and the resin layer (B). This laminate can be used directly as the optical film of the present invention, or, for example, the other layers (C) can be attached to the surface of the resin layer (B) opposite to the light-transmitting substrate (A) using the adhesive layer to form the optical film of the present invention.

[0107] [3. Optical components and image display devices]

[0108] The optical components of this invention are not particularly limited; for example, they can be polarizing plates. The polarizing plates themselves are also not particularly limited; for example, they may include the optical thin film and polarizing element of this invention, or they may also include other constituent elements. The constituent elements of the polarizing plate can be bonded together, for example, using adhesives or bonding agents.

[0109] The image display device of the present invention is not particularly limited and can be any image display device, such as liquid crystal display device, organic EL display device, etc.

[0110] The image display device of the present invention may be, for example, an image display device having the optical thin film of the present invention on the visual recognition side surface, and the image display device having a black matrix pattern.

[0111] The optical film of the present invention can, for example, be bonded to an optical component for an LCD using an adhesive or bonding agent, with the light-transmitting substrate (A) side attached. It should be noted that during this bonding process, the surface of the light-transmitting substrate (A) can undergo various surface treatments as described above. As described above, the method for manufacturing the optical film according to the present invention allows for free control of the surface shape of the optical film within a wider range. Therefore, the optical properties obtained by laminating the optical film with other optical components using adhesives or bonding agents can cover a wider range corresponding to the surface shape of the optical film.

[0112] Examples of such optical components include polarizing elements or polarizing plates. Polarizing plates typically have transparent protective films on one or both sides of the polarizing element. When transparent protective films are provided on both sides of the polarizing element, the transparent protective films on the front and back sides can be made of the same material or different materials. Polarizing plates are usually disposed on both sides of a liquid crystal cell. Furthermore, the polarizing plates are arranged such that the absorption axes of the two polarizing plates are approximately orthogonal to each other.

[0113] The configuration of the polarizing plate having the aforementioned optical thin film stacked is not particularly limited. For example, it can be configured such that a transparent protective film, the aforementioned polarizing element, and the aforementioned transparent protective film are stacked sequentially on the aforementioned optical thin film, or it can be configured such that the aforementioned polarizing element and the aforementioned transparent protective film are stacked sequentially on the aforementioned optical thin film.

[0114] The image display device of the present invention has the same configuration as conventional image display devices, except that the optical thin film is arranged in a specific direction. For example, in the case of an LCD, it can be manufactured by appropriately assembling various components such as liquid crystal cells, polarizing plates, and illumination systems (backlights, etc.) used as needed, and incorporating driving circuits.

[0115] The optical film of this invention has no particular limitation on its application and can be used for any purpose. Examples of its applications include personal computer monitors, laptops, copiers and other office automation (OA) equipment, mobile phones, watches, digital cameras, portable information terminals (PDAs), portable game consoles and other portable devices, cameras, televisions, microwave ovens and other household electrical appliances, rearview monitors, car navigation system monitors, car audio systems and other in-vehicle equipment, commercial store information monitors and other display equipment, surveillance monitors and other security equipment, nursing monitors, medical monitors and other nursing and medical equipment, etc.

[0116] Example

[0117] Next, embodiments of the present invention will be described together with comparative examples. However, the present invention is not limited to the following embodiments and comparative examples.

[0118] It should be noted that in the following examples and comparative examples, the number of parts of substances is by mass (parts by weight) unless otherwise specified.

[0119] [Example 1]

[0120] The optical film of the present invention having a resin layer (hard coating) (B) formed on a light-transmitting substrate (A) is manufactured as described below.

[0121] As the resin contained in the hard coating, 40 parts by weight of UV-curable acrylic resin (manufactured by Toa Synthetic Co., Ltd., trade name "M-920", 100% solids content) and 60 parts by weight of UV-curable acrylic resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name "UV-1700TL", 80% solids content) were prepared. Relative to the above resin solids content of 100 parts by weight, 3 parts by weight of photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907") and 0.12 parts by weight of leveling agent (manufactured by Kyoei Chemical Co., Ltd., trade name "LE-303", 40% solids content) were mixed. This mixture was diluted with a MIBK / cyclopentanone mixed solvent (weight ratio 70 / 30) to a solids content concentration of 30%, thereby preparing a coating liquid (E1) for forming a hard coating.

[0122] A transparent plastic film substrate (TAC, manufactured by Konica Minolta Co., Ltd., trade name "KC2UA") is prepared as the light-transmitting substrate (A). Next, the aforementioned hard coating forming coating liquid (E1) is applied to one side of the transparent plastic film substrate using a bar coater to form a coating layer (coating process). The transparent plastic film substrate with the coating layer formed is then conveyed to a drying process (coating film forming process). Furthermore, in the drying process (coating film forming process), it is heated at 80°C for 1 minute, thereby drying the coating layer to form a coating film. Afterwards, the coating film is irradiated with a high-pressure mercury lamp, accumulating a light intensity of 240 mJ / cm². 2 The coating is cured by ultraviolet light (curing process) to form a hard coating layer (resin layer (B)) with a thickness of 2.0 μm. As described above, the hard coating film (optical film) of Example 1, in which the resin layer (B) is formed on the light-transmitting substrate (A), is obtained.

[0123] [Example 2]

[0124] The optical film of the present invention having a resin layer (hard coating) (B) formed on a light-transmitting substrate (A) is manufactured as described below.

[0125] As the resin contained in the hard coating, 40 parts by weight of UV-curable acrylic resin (manufactured by Toa Synthetic Co., Ltd., trade name "M-920", 100% solids content) and 60 parts by weight of UV-curable acrylic resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name "UV-1700TL", 80% solids content) were prepared. Relative to the above resin solids content of 100 parts by weight, 3 parts by weight of photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907") and 0.20 parts by weight of leveling agent (manufactured by Kyoei Chemical Co., Ltd., trade name "LE-303", 40% solids content) were mixed. This mixture was diluted with a MIBK / cyclopentanone mixed solvent (weight ratio 70 / 30) to a solids content concentration of 30%, thereby preparing a coating liquid (E2) for forming a hard coating.

[0126] A transparent plastic film substrate (TAC, manufactured by Konica Minolta Co., Ltd., trade name "KC2UA") is prepared as the light-transmitting substrate (A). Next, the aforementioned hard coating forming coating liquid (E2) is applied to one side of the transparent plastic film substrate using a bar coater to form a coating layer (coating process). The transparent plastic film substrate with the coating layer formed is then conveyed to a drying process (coating film forming process). Furthermore, in the drying process (coating film forming process), it is heated at 80°C for 1 minute, thereby drying the coating layer to form a coating film. Afterwards, the coating film is irradiated with a high-pressure mercury lamp, accumulating a light intensity of 240 mJ / cm². 2The coating is cured by ultraviolet light (curing process) to form a hard coating layer (resin layer (B)) with a thickness of 2.0 μm. As described above, the hard coating film (optical film) of Example 2, in which the resin layer (B) is formed on the light-transmitting substrate (A), is obtained.

[0127] [Example 3]

[0128] The optical film of the present invention having a resin layer (hard coating) (B) formed on a light-transmitting substrate (A) is manufactured as described below.

[0129] As the resin contained in the hard coating, 50 parts by weight of UV-curable acrylic resin (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "A-DCP", 100% solids content) and 50 parts by weight of UV-curable acrylic resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name "UV-1700TL", 80% solids content) were prepared. Relative to the above resin solids content of 100 parts by weight, 5 parts by weight of photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907") and 0.20 parts by weight of leveling agent (manufactured by Kyoei Chemical Co., Ltd., trade name "LE-303", 40% solids content) were mixed. This mixture was diluted with a MIBK / cyclopentanone mixed solvent (weight ratio 60 / 40) to a solids content concentration of 30%, thereby preparing a coating liquid (E3) for forming a hard coating.

[0130] A transparent plastic film substrate (TAC, manufactured by Fujifilm Corporation, trade name "TJ25UL") is prepared as the light-transmitting substrate (A). Next, the aforementioned hard coating forming coating liquid (E3) is applied to one side of the transparent plastic film substrate using a bar coater to form a coating layer (coating process). The transparent plastic film substrate with the coating layer formed is then conveyed to a drying process (coating film forming process). Furthermore, in the drying process (coating film forming process), it is heated at 60°C for 1 minute, thereby drying the coating layer to form a coating film. Afterwards, the coating film is irradiated with a high-pressure mercury lamp, accumulating a light intensity of 220 mJ / cm². 2 The coating is cured by ultraviolet light (curing process) to form a hard coating layer (resin layer (B)) with a thickness of 2.5 μm. As described above, the hard coating film (optical film) of Example 3, in which the resin layer (B) is formed on the light-transmitting substrate (A), is obtained.

[0131] [Example 4]

[0132] The optical film of the present invention having a resin layer (hard coating) (B) formed on a light-transmitting substrate (A) is manufactured as described below.

[0133] As the resin contained in the hard coating, 50 parts by weight of UV-curable acrylic resin (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "A-DCP", 100% solids content) and 50 parts by weight of UV-curable acrylic resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name "UV-1700TL", 80% solids content) were prepared. Relative to the above resin solids content of 100 parts by weight, 5 parts by weight of photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907") and 0.10 parts by weight of leveling agent (manufactured by Kyoei Chemical Co., Ltd., trade name "LE-303", 40% solids content) were mixed. This mixture was diluted with a MIBK / cyclopentanone mixed solvent (weight ratio 60 / 40) to a solids content concentration of 30%, thereby preparing a coating liquid (E4) for forming a hard coating.

[0134] A transparent plastic film substrate (TAC, manufactured by Fujifilm Corporation, trade name "TJ25UL") is prepared as the light-transmitting substrate (A). A coating layer (coating process) is formed by applying the hard coating forming liquid (E4) to one side of the transparent plastic film substrate using a bar coater. The transparent plastic film substrate with the coating layer is then conveyed to a drying process (coating film forming process). Furthermore, in the drying process (coating film forming process), the substrate is heated at 60°C for 1 minute, thereby drying the coating layer to form a coating film. Afterwards, the coating film is irradiated with a high-pressure mercury lamp, accumulating a light intensity of 220 mJ / cm². 2 The coating is cured by ultraviolet light (curing process) to form a hard coating layer (resin layer (B)) with a thickness of 2.5 μm. As described above, the hard coating film (optical film) of Example 4, in which the resin layer (B) is formed on the light-transmitting substrate (A), is obtained.

[0135] [Comparative Example 1]

[0136] An optical film having a resin layer (hard coating) formed on a light-transmitting substrate is manufactured as described below.

[0137] As the resin contained in the hard coating, 40 parts by weight of UV-curable acrylic resin (manufactured by Toa Synthetic Co., Ltd., trade name "M-920", 100% solids content) and 60 parts by weight of UV-curable acrylic resin (manufactured by Mitsubishi Chemical Corporation, trade name "UV-1700TL", 80% solids content) were prepared. Relative to the above resin solids content of 100 parts by weight, 3 parts by weight of photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907") and 0.01 parts by weight of leveling agent (manufactured by DIC Corporation, trade name "PC4100", 40% solids content) were mixed. This mixture was diluted with a MIBK / cyclopentanone mixed solvent (weight ratio 72 / 28) to a solids content concentration of 25%, thereby preparing a coating liquid (C1) for forming a hard coating.

[0138] A transparent plastic film substrate (TAC, manufactured by Konica Minolta Co., Ltd., trade name "KC2UA") was prepared as the light-transmitting substrate. It should be noted that this light-transmitting substrate (transparent plastic film substrate) is the same as the light-transmitting substrate (A) of Example 1. A coating layer was formed by applying the aforementioned hard coating forming liquid (C1) to one side of the transparent plastic film substrate using a bar coater. Then, the transparent plastic film substrate with the coating layer formed was conveyed to a drying process. In the drying process, it was heated at 80°C for 1 minute, thereby drying the coating layer and forming a coating film. Afterwards, the coating film was irradiated with a high-pressure mercury lamp, accumulating a light intensity of 240 mJ / cm². 2 The coating was cured by ultraviolet light to form a hard coating with a thickness of 2.0 μm. This process was repeated to obtain a hard coating film of Comparative Example 1, on which the hard coating was formed on the light-transmitting substrate.

[0139] [Comparative Example 2]

[0140] An optical film having a resin layer (hard coating) formed on a light-transmitting substrate is manufactured as described below.

[0141] As the resin contained in the hard coating, 40 parts by weight of UV-curable acrylic resin (manufactured by Toa Synthetic Co., Ltd., trade name "M-920", 100% solids content) and 60 parts by weight of UV-curable acrylic resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name "UV-1700TL", 80% solids content) were prepared. Relative to the above resin solids content of 100 parts by weight, 3 parts by weight of photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907") and 0.10 parts by weight of leveling agent (manufactured by Kyoei Chemical Co., Ltd., trade name "LE-303", 40% solids content) were mixed. This mixture was diluted with a MIBK / cyclopentanone mixed solvent (weight ratio 70 / 30) to a solids content concentration of 30%, thereby preparing a coating liquid (C2) for forming a hard coating.

[0142] A transparent plastic film substrate (TAC, manufactured by Konica Minolta Co., Ltd., trade name "KC2UA") was prepared as the light-transmitting substrate. It should be noted that this light-transmitting substrate (transparent plastic film substrate) is the same as the light-transmitting substrate (A) of Example 1. A coating layer was formed by applying the aforementioned hard coating forming liquid (C2) to one side of the transparent plastic film substrate using a bar coater. Then, the transparent plastic film substrate with the coating layer formed was conveyed to a drying process. In the drying process, the coating layer was heated at 80°C for 1 minute to dry it, forming a coating film. Afterwards, the coating film was irradiated with a high-pressure mercury lamp, accumulating a light intensity of 240 mJ / cm². 2 The coating was cured by ultraviolet light to form a hard coating with a thickness of 2.0 μm. This process was repeated to obtain a hard coating film of Comparative Example 2, on which the hard coating was formed on the light-transmitting substrate.

[0143] [Comparative Example 3]

[0144] An optical film having a resin layer (hard coating) formed on a light-transmitting substrate is manufactured as described below.

[0145] As the resin contained in the hard coating, 40 parts by weight of UV-curable acrylic resin (manufactured by Toa Synthetic Co., Ltd., trade name "M-920", 100% solids content) and 60 parts by weight of UV-curable acrylic resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name "UV-1700TL", 80% solids content) were prepared. Relative to the above resin solids content of 100 parts by weight, 3 parts by weight of photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907") and 0.50 parts by weight of leveling agent (manufactured by Kyoei Chemical Co., Ltd., trade name "LE-303", 40% solids content) were mixed. This mixture was diluted with a MIBK / cyclopentanone mixed solvent (weight ratio 70 / 30) to a solids content concentration of 30%, thereby preparing a coating liquid (C3) for forming a hard coating.

[0146] A transparent plastic film substrate (TAC, manufactured by Konica Minolta Co., Ltd., trade name "KC2UA") was prepared as the light-transmitting substrate. It should be noted that this light-transmitting substrate (transparent plastic film substrate) is the same as the light-transmitting substrate (A) of Example 1. A coating layer was formed by applying the hard coating forming liquid (C3) to one side of the transparent plastic film substrate using a bar coater. Then, the transparent plastic film substrate with the coating layer formed was conveyed to a drying process. In the drying process, it was heated at 80°C for 1 minute, thereby drying the coating layer and forming a coating film. Afterwards, the coating film was irradiated with a high-pressure mercury lamp with a cumulative light intensity of 240 mJ / cm². 2 The coating was cured by ultraviolet light to form a hard coating with a thickness of 2.0 μm. This process was repeated to obtain a hard coating film of Comparative Example 3, on which the hard coating was formed on the light-transmitting substrate.

[0147] [Determination of the silicon atom ratio]

[0148] For the optical films (hard-coated films) of the above embodiments and comparative examples, XPS measurement based on the following measurement method was used to determine the ratio of the number of silicon atoms to the total number of carbon, nitrogen, oxygen and silicon atoms at a depth of 1 nm from the surface of the resin layer (B) or the resin layer of the comparative example that is opposite to the surface of the light-transmitting substrate (A) or the light-transmitting substrate of the comparative example.

[0149] (XPS measurement)

[0150] The atomic ratio of silicon (Si) atoms in the hard-coated resin layer of the hard-coated films in the examples and comparative examples was determined using XPS (X-ray Photoelectron Spectroscopy) within a depth of 1 nm from the surface opposite to the transparent substrate. It should be noted that XPS is also known as ESCA (Electron Spectroscopy for Chemical Analysis). As for the measurement conditions, the hard-coated films used as test samples were cut into 5 mm × 5 mm squares, fixed to the sample stage with a Mo (molybdenum) plate, and measured under the conditions described below. Specifically, a wide-scan measurement was first performed on the test samples under the following measurement conditions for qualitative analysis. Furthermore, narrow-scan measurements were performed on C (carbon), N (nitrogen), O (oxygen), Si (silicon), and F (fluorine) at a depth of 1 nm, and the percentage of Si (silicon) atoms was calculated when the sum of the total number of C (carbon), N (nitrogen), O (oxygen), Si (silicon), and F (fluorine) atoms was 100%.

[0151] XPS measurement conditions:

[0152] Test sample: Hard coated film, 5mm × 5mm square

[0153] Device; ULVAC-PHI Quantera SXM

[0154] X-ray source; monochromatic Al Ka.

[0155] Xray Setting; [15kV, 30W]

[0156] Photoelectron extraction angle: 10 degrees relative to the sample surface (analysis depth: 1 nm)

[0157] Binding energy correction; the peak from the C1s bond in the C1s spectrum was corrected to 285.0 eV.

[0158] [Confirmation of the presence or absence of shrinkage cavities]

[0159] The hard-coated films (optical films) of the above embodiments and comparative examples were cut into rectangles of 440 mm × 1000 mm as test samples. For these test samples, the presence or absence of pinholes (discrepancies) was confirmed using the following measurement methods: orange light reflection test, Z-light reflection test, point light source transmission test, and fiber light reflection test. As a result, optical films that showed no pinholes in all of the following measurement methods were determined to be "pinhole-free," and optical films that showed pinholes in one or more of the following measurement methods were determined to be "pinhole-containing."

[0160] <Method for confirming shrinkage holes: Orange light reflection inspection>

[0161] Orange light (manufactured by Funatech, model "FNA-35") was shone parallel to the hard coating surface of the hard coating film used as the test sample (the surface on the side where the resin layer (B) is formed for the transparent substrate (A), or the surface on the side where the resin layer is formed for the transparent substrate of the comparative example. The same applies below). As a result, when the hard coating surface was checked at an angle of 45 degrees relative to the test sample and at a distance of 300 mm from the center of the hard coating surface, samples in which pinholes (showing unevenness) could be visually identified were recorded as "with pinholes", and samples in which pinholes (showing unevenness) could not be visually identified were recorded as "without pinholes".

[0162] <Method for confirming pinholes: Z-ray reflection inspection>

[0163] For the hard-coated surface of the hard-coated film used as the test sample, Z-light (manufactured by Yamada Electric Co., Ltd., model "Z-208") was irradiated at a 45-degree angle from a distance of 400 mm. As a result, when the hard-coated surface was checked at an angle of 45 degrees (90 degrees from the light source) from a distance of 300 mm from the center of the hard-coated surface, samples in which pinholes (unevenness) could be visually identified were recorded as "with pinholes", and samples in which pinholes could not be visually identified were recorded as "without pinholes".

[0164] <Method for confirming shrinkage holes: Point light source transmission inspection>

[0165] A point light source (Hamamatsu Photonics KK, model "L8425-01") is used to illuminate the sample from a position 560 mm away from the center of the hard coating surface at an angle of 45 degrees relative to the hard coating surface. The transmitted light, which penetrates the sample, is projected onto a white board positioned 1050 mm away from the point light source. In other words, the sample is positioned between the point light source and the white board, and the illumination and projection of the transmitted light are performed. The transmitted light projected onto the white board under these conditions is visually identified. Samples with visible pinholes (uneven distribution) are marked as "with pinholes," while samples without visible pinholes are marked as "without pinholes."

[0166] <Method for confirming pinholes: Fiberoptic light reflection inspection>

[0167] A fiber optic light (MEC, model "INS-1303-103" (custom-made)) was used to illuminate the hard-coated film, which was being tested, at an angle of 45 degrees relative to the hard-coated surface, 400 mm from the center of the hard-coated surface. As a result, when the hard-coated surface was examined at an angle of 45 degrees (90 degrees from the light source) from the test sample, 300 mm from the center of the hard-coated surface, samples with pinholes (indicating unevenness) whose outlines were only visually identifiable by strong defects were recorded as "with pinholes," while samples without visible pinholes were recorded as "without pinholes."

[0168] [Manufacturing of hard-coated thin films (optical thin films) with other layers (C)]

[0169] For the hard-coated films (optical films) of the above embodiments and comparative examples, a surface protective film with adhesive, "E-MASK (trade name)" manufactured by Nitto Denko Corporation, was attached as an additional layer (C) and an adhesive layer, thereby manufacturing the above-mentioned hard-coated films (optical films) having the additional layer (C). It should be noted that for the above-mentioned surface protective film "E-MASK (trade name)," the following three types (1), (2), and (3) were manufactured. For the hard-coated films (optical films) of the above embodiments and comparative examples, three types of hard-coated films (optical films) having the additional layer (C) corresponding to "E-MASK (trade name)" (1), (2), and (3) were manufactured respectively. It should be noted that the measurement results of the characteristics of "ring marks," "contamination," and "stop marks" described later were obtained for the three types of hard-coated films corresponding to "E-MASK (trade name)" (1), (2), and (3).

[0170] [Manufacturing method of E-MASK(1)]

[0171] The E-MASK is manufactured as described below (1).

[0172] (Manufacturing of the coating agent)

[0173] A dispersion of 25% polyester resin (trade name "Binarol MD-1480", manufactured by Toyobo Co., Ltd., an aqueous dispersion of saturated copolyester resin) (binder dispersion) was prepared as an adhesive. Additionally, an aqueous dispersion of carnauba wax (wax ester) was prepared as a lubricant (lubricant dispersion). Furthermore, an aqueous solution (trade name "Baytron P", manufactured by HCStark Co., Ltd.), containing 0.5% poly(3,4-dioxothiophene) (PEDOT) and 0.8% polystyrene sulfonate (number average molecular weight 150,000) (PSS), was prepared as a conductive polymer (conductive polymer aqueous solution).

[0174] To a mixed solvent prepared by mixing water and ethanol in a 1:1 mass ratio, add 100 parts by weight of the above-mentioned binder dispersion, 30 parts by weight of the above-mentioned lubricant dispersion, 50 parts by weight of the above-mentioned conductive polymer aqueous solution, and a melamine-based crosslinking agent, and stir for about 20 minutes to mix thoroughly. This produces a coating agent with approximately 0.15% NV.

[0175] (Formation of the topcoat)

[0176] A transparent polyethylene terephthalate (PET) film with a thickness of 38 μm, a width of 30 cm, and a length of 40 cm was prepared, on one side (the first side) of which was subjected to corona treatment. The aforementioned coating agent was applied to the corona-treated surface of the PET film using a bar coater, and then dried by heating at 130°C for 2 minutes. This produced a substrate (substrate with a topcoat) having a transparent topcoat layer with a thickness of 10 nm on the first side of the PET film.

[0177] (Preparation of the adhesive composition)

[0178] 200 parts by weight of 2-ethylhexyl acrylate, 8 parts by weight of 2-hydroxyethyl acrylate, 0.4 parts by weight of 2,2'-azobisisobutyronitrile (2,2'-azobisisobutyronitrile) as a polymerization initiator, and 312 parts by weight of ethyl acetate as a solvent were added to a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet, and condenser. Nitrogen gas was introduced while stirring slowly to maintain the liquid temperature in the flask at approximately 65°C, and the polymerization reaction was carried out for 6 hours to produce an acrylic polymer solution (40% by weight). The above acrylic polymer has a weight-average molecular weight of 540,000, a glass transition temperature (Tg) of -68°C, and an acid value of 0.0.

[0179] The above-mentioned acrylic polymer solution (40% by weight) was diluted with ethyl acetate to 20% by weight. Relative to 100 parts by weight of the solid components in the solution, 0.3 parts by weight of ammonium polyoxyethylene nonylpropene phenyl ether sulfate (trade name "Aqualon HS-10", manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an anionic surfactant, 3 parts by weight of isocyanurate derivative of hexamethylene diisocyanate (trade name "CORONATE HX", manufactured by Nippon Polyurethane Kogyo Co., Ltd.) as a crosslinking agent, 0.03 parts by weight of dibutyltin dilaurate (trade name "OL-1", manufactured by Tokyo Fine Chemical Co., Ltd., 0.5% ethyl acetate solution) as a crosslinking catalyst, and acetylacetone as a crosslinking delay agent in a total solvent volume of 3 parts by weight were added. The mixture was stirred to prepare an acrylic adhesive composition.

[0180] (Manufacturing of E-MASK(1))

[0181] A release sheet was prepared by applying a silicone-based release agent to one side of a PET film. The acrylic adhesive composition was coated onto the release sheet's release surface (the surface where the release treatment was applied), and dried at 130°C for 1 minute to form an acrylic adhesive layer (adhesive layer) with a thickness of 10 μm. This acrylic adhesive layer was then bonded to the other side (the second side, i.e., the side without the topcoat) of the coated substrate and cured (aged) at 50°C and 15% RH for 3 days to obtain an E-MASK (1) as a surface protective film (adhesive sheet). This surface protective film (E-MASK (1)) has the coated substrate as the other layer (C) and the acrylic adhesive layer as the adhesive layer.

[0182] [Manufacturing method of E-MASK(2)]

[0183] The thickness of the acrylic adhesive layer (adhesive layer) is changed from 10 μm to 20 μm, and the surface protective film (E-MASK (2)) is manufactured by the same manufacturing method as the E-MASK (1) described above. The surface protective film (E-MASK (2)) has the substrate with the topcoat as the other layer (C) and the acrylic adhesive layer as the adhesive layer.

[0184] [Manufacturing method of E-MASK(3)]

[0185] The E-MASK is manufactured as described below (3).

[0186] (Manufacturing of (meth)acrylic acid polymers)

[0187] 100 parts by weight of 2-ethylhexyl acrylate (2EHA), 10 parts by weight of 4-hydroxybutyl acrylate (4HBA), 0.02 parts by weight of acrylic acid (AA), 0.2 parts by weight of 2,2'-azobisisobutyronitrile (2,2'-azobisisobutyronitrile) as a polymerization initiator, and 157 parts by weight of ethyl acetate were added to a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet, and condenser. Nitrogen gas was introduced while stirring slowly to maintain the liquid temperature in the flask at approximately 65°C, and the polymerization reaction was carried out for 6 hours to produce a (meth)acrylic acid polymer solution (40% by weight). The weight-average molecular weight of the above acrylic polymer is 540,000, and the glass transition temperature (Tg) is -67°C.

[0188] (Manufacturing of acrylic oligomers)

[0189] To a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet pipe, condenser, and dropping funnel, add 100 parts by weight of toluene, 60 parts by weight of dicyclopentyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), 40 parts by weight of methyl methacrylate (MMA), and 3.5 parts by weight of methyl mercaptoacetate as a chain transfer agent. Then, after stirring at 70°C under a nitrogen atmosphere for 1 hour, 0.2 parts by weight of 2,2'-azobisisobutyronitrile (2,2'-azobisisobutyronitrile) as a polymerization initiator is added. The reaction is carried out at 70°C for 2 hours, followed by a reaction at 80°C for 4 hours, and then at 90°C for 1 hour, thereby obtaining an acrylic oligomer. The weight-average molecular weight of the above acrylic oligomer is 4000, and the glass transition temperature (Tg) is 144°C.

[0190] (Preparation of adhesive solution)

[0191] The above-mentioned (meth)acrylic acid polymer solution (40% by weight) was diluted to 20% by weight with ethyl acetate. To 500 parts by weight (100 parts by weight of solids) of this solution, the following were added: 0.5 parts by weight of the above-mentioned acrylic oligomer (solids); 2 parts by weight (solids) of a solution containing an oxyalkylene chain-containing organosiloxane (KF-353, manufactured by Shin-Etsu Chemical Co., Ltd.) diluted to 10% with ethyl acetate; 15 parts by weight (solids) of an alkali metal salt (ionic compound) as an antistatic agent, namely lithium bis(trifluoromethanesulfonyl)imide (LiN(CF3SO2)2:LiTFSI, manufactured by Tokyo Chemical Industry Co., Ltd.), diluted to 1% with ethyl acetate; and the trifunctional isocyanate compound, namely hexamethylene diisocyanate isocyanurate (manufactured by Nippon Polyurethane Co., Ltd., CORONATE), as a crosslinking agent. An acrylic adhesive solution is prepared by mixing and stirring 3.5 parts by weight of HX (3.5 parts by weight of solids), 0.3 parts by weight of 1,3-bis(isocyanate methyl)cyclohexane (manufactured by Mitsui Chemicals, TAKENATE 600) (0.3 parts by weight of solids) as a difunctional isocyanate compound, and 2 parts by weight of dibutyltin dilaurate (1% ethyl acetate solution) (0.02 parts by weight of solids) as a crosslinking catalyst.

[0192] (Manufacturing of antistatic treated film)

[0193] An antistatic agent solution was prepared by diluting 10 parts by weight of an antistatic agent (manufactured by SOLVEX, MICROSOLVER RMd-142, with tin oxide and polyester resin as the main components) with a mixed solvent containing 30 parts by weight of water and 70 parts by weight of methanol.

[0194] The obtained antistatic agent solution was coated onto a polyethylene terephthalate (PET) film (thickness: 38 μm) using a bar coater, and dried at 130 °C for 1 minute to remove the solvent, forming an antistatic layer (thickness: 0.2 μm), thereby manufacturing an antistatic treated film.

[0195] (Manufacturing of E-MASK(3))

[0196] The acrylic adhesive solution described above was applied to the surface of the antistatic film opposite to the antistatic treated surface, and heated at 130°C for 2 minutes to form an adhesive layer with a thickness of 15 μm. Next, the silicone-treated surface of a polyethylene terephthalate film (25 μm thick) that had undergone silicone treatment on one side was adhered to the surface of the adhesive layer to obtain an E-MASK (3) as a surface protective film (adhesive sheet). This surface protective film (E-MASK (3)) has the antistatic treated film as the other layer (C) and the acrylic adhesive layer as the adhesive layer.

[0197] [Determination of water contact angle]

[0198] For the hard-coated film (optical film) with other layers (C) manufactured as described above, the water contact angle d2 of the adhesive layer surface was measured using the following method. First, the hard-coated film (optical film) with other layers (C) was left to stand for 24 hours at room temperature (24±2°C) and relative humidity (50±20%). Then, the other layers (C) were peeled off to expose the adhesive layer. Next, using a water contact angle measuring device (trade name "DM-301", manufactured by Kyowa Interface Science Co., Ltd.), approximately 4.0 μL of water was dropped onto the adhesive layer surface with the other layers (C) attached using the droplet method at room temperature (24±2°C) and relative humidity (50±20%). The angle between the surface of the adhered object and the tangent at the tip of the water droplet was measured one second after the drop was placed, and this angle was taken as the water contact angle (°). Furthermore, the same measurement was performed at five points within the sample, and the average value of these five measurements was taken as the water contact angle d2 (°) of the adhesive layer surface.

[0199] Furthermore, the water contact angle d1 (°) of the surface of the resin layer (B) of the optical films (hard-coated films) of the above embodiments and comparative examples, which do not have the above adhesive layer and the other layers (C) on the surface of the above resin layer (B), was measured by the same method.

[0200] The results of the above-mentioned water contact angles d1 and d2 are shown in Tables 1 to 6 below. As shown in Tables 1 to 6 below, when any one of E-MASK (1), E-MASK (2), and E-MASK (3) is used, the water contact angle d2 of the above-mentioned adhesive layer surface is 90% or less (more than 10%) of the water contact angle d1 of the above-mentioned resin layer (B) surface.

[0201] [Table 1]

[0202] Water contact angles d1 (°) and d2 (°) in Example 1

[0203]

[0204] [Table 2]

[0205] Water contact angles d1 (°) and d2 (°) in Example 2

[0206]

[0207] [Table 3]

[0208] Water contact angles d1 (°) and d2 (°) in Example 3

[0209]

[0210] [Table 4]

[0211] Water contact angles d1 (°) and d2 (°) in Example 4

[0212]

[0213] [Table 5]

[0214] Compare the water contact angles d1 (°) and d2 (°) in Example 2.

[0215]

[0216] [Table 6]

[0217] Compare the water contact angles d1 (°) and d2 (°) in Example 3.

[0218]

[0219] [Product SPV Test]

[0220] For the hard-coated thin film (optical thin film) with other layers (C) manufactured as described above, the characteristics of "ring mark", "contamination" and "stop mark" are measured and evaluated using the following measurement methods. In this embodiment, these measurements and evaluations are collectively referred to as "product SPV test".

[0221] <Circular Marks: Evaluation Methods>

[0222] The hard-coated film (optical film) with the other layers (C) described above was cut into 40mm × 40mm squares as test samples. The light-transmitting substrate side of the test sample was attached to an acrylic sheet with adhesive, and the protective film (the other layers (C)) of the test sample was temporarily peeled off. It was then reattached while air bubbles were present. After being placed at room temperature (24±2℃) and relative humidity (50±20%) for a specified time (120 hours or 240 hours), the protective film was peeled off to check for visible air bubble marks.

[0223] <Circular Marks: Judgment Criteria>

[0224] The case where no ring-shaped mark can be seen after 240 hours in a dark outdoor environment is judged as ○, and the case where a ring-shaped mark can be seen under the same conditions is judged as ×.

[0225] <Pollution: Assessment Methods>

[0226] The aforementioned hard-coated film (optical film) with the other layers (C) was cut into 40mm × 40mm squares as test samples. The light-transmitting substrate side of the test sample was attached to an acrylic sheet with adhesive, and placed in an oven under specified conditions (60°C, 60°C / 90% humidity). A thermostat (ESPEC CORP., trade name PH(H)-202) or a low-temperature thermo-humidifier (ESPEC CORP., trade name PL-2J) was used as the oven. Afterwards, the test samples were removed after specified times (120 hours, 240 hours, or 500 hours), and the protective film (the aforementioned other layers (C)) was peeled off. Adhesive tape (NICHIBAN Co., Ltd., trade name "Cero Tape Large Roll CT405AP-24") was attached to the surface of the peeled adhesive layer, and contamination was then confirmed by visual inspection.

[0227] <Pollution: Judgment Criteria>

[0228] A case where no contamination is visible even after 500 hours in a dark outdoor environment is classified as ○, while a case where contamination is visible under the same conditions is classified as ×.

[0229] <Stop Tracking: Evaluation Methods>

[0230] The hard-coated film (optical film) with the other layers (C) described above was cut into rectangles of 25 mm × 100 mm as test samples. The light-transmitting substrate side of the test sample was attached to an acrylic sheet with adhesive, and placed in an oven under specified conditions (60°C, 40°C / 92% humidity). A thermostat (ESPEC CORP., trade name PH(H)-202) or a low-temperature thermo-humidifier (ESPEC CORP., trade name PL-2J) was used as the oven. Afterwards, the test samples were removed after a specified time (120 hours). Peeling was temporarily stopped when half of the protective film (the other layers (C)) of the test sample was peeled off, and the remaining protective film was then peeled off. Visual inspection was used to confirm whether any stopping marks (marks of the protective film) were visible.

[0231] <Stop Tracks: Judgment Criteria>

[0232] The case where no stopping marks are visible after 120 hours in a dark outdoor environment is marked as ○, and the case where stopping marks are visible under the same conditions is marked as ×.

[0233] The silicon atom ratio (Si element ratio), presence or absence of pinholes, and SPV test results of the product as measured above are summarized in Table 7 below. In Table 7 below, "Si element ratio at 1 nm on the HC surface" means the ratio of the number of silicon atoms to the total number of carbon, nitrogen, oxygen, and silicon atoms at a depth of 1 nm from the surface opposite to the light-transmitting substrate (A) or the light-transmitting substrate of the comparative example in the above resin layer (B).

[0234] [Table 7]

[0235]

[0236] As shown in Table 7 above, the optical films of the embodiments that satisfy all the requirements of the present invention are free of pinholes, and the SPV test results of the products are all good, thus confirming that display performance defects are suppressed. In contrast, the Si element ratio of Comparative Example 2 is 4.7%, which does not meet the conditions of the present invention (5.0-9.0%). As a result, the SPV test results of Comparative Example 2 are good, but pinholes are present. In addition, the Si element ratio of Comparative Example 3 is 9.2%, which does not meet the conditions of the present invention (5.0-9.0%). As a result, Comparative Example 3 is free of pinholes, but the SPV test results of the products are poor. In addition, the Si element ratio of Comparative Example 1 is 1.2%, which deviates significantly from the conditions of the present invention (5.0-9.0%). As a result, pinholes frequently occur in Comparative Example 1. Therefore, for the optical film of Comparative Example 1, since it did not reach the level of confirming the product SPV test results and was obviously not practical, the product SPV test was not conducted.

[0237] Industrial availability

[0238] As explained above, according to the present invention, an optical thin film capable of suppressing or preventing poor display characteristics, a method for manufacturing the optical thin film, an optical component, and an image display device can be provided. The application of the optical thin film of the present invention is not particularly limited; for example, it can be applied to any widely used image display device.

[0239] This application claims priority based on Japanese Application Special Purpose 2020-143056 filed on August 26, 2020 and Japanese Application Special Purpose 2021-051002 filed on March 25, 2021, the entire contents of which are incorporated herein by reference.

Claims

1. An optical thin film, characterized in that, A resin layer (B) is formed on a light-transmitting substrate (A). The elements constituting the resin layer (B) include silicon. The thickness of the resin layer (B) is 1.0~4.5μm. In the resin layer (B), the number of atoms at a depth of 1 nm from the surface opposite to the light-transmitting substrate (A) satisfies the following mathematical formula (1). On the surface of the resin layer (B) opposite to the light-transmitting substrate (A), another layer (C) is attached using an adhesive layer. 5.0≤[(n Si / n total )×100]≤8.5 (1) In the mathematical formula (1), n total n is the total number of atoms of carbon, nitrogen, oxygen, and silicon. Si This represents the number of silicon atoms.

2. The optical thin film according to claim 1, wherein, The resin layer (B) contains a surface conditioner. The elements constituting the surface modifier include silicon.

3. The optical thin film according to claim 2, wherein, The surface modifier comprises a silicon compound having a dimethylsiloxane backbone.

4. The optical thin film according to claim 1 or 2, wherein, The resin layer (B) is formed by a copolymer of oligomers with functional groups and monomers.

5. The optical thin film according to claim 1 or 2, wherein, The resin layer (B) is a hard coating.

6. The optical thin film according to claim 1 or 2, wherein, The adhesive layer satisfies the condition of the following mathematical formula (2). (d1-d2) / d1≥0.10 (2) In the mathematical formula (2), d1 is the water contact angle (°) of the surface of the resin layer (B) when there is no adhesive layer and the other layer (C) on the surface of the resin layer (B), and d2 is the water contact angle (°) of the surface of the adhesive layer after the other layer (C) is peeled off from the adhesive layer.

7. The optical thin film according to claim 1 or 2, wherein, The other layer (C) is a glass or resin film.

8. A method for manufacturing an optical thin film according to any one of claims 1 to 7, characterized in that, It includes: a resin layer (B) forming process in which the resin layer (B) is formed on the light-transmitting substrate (A) in a manner satisfying the mathematical formula (1); and In the process of attaching other layers (C) to the resin layer (B) on the side opposite to the light-transmitting substrate (A) using an adhesive layer, The resin layer (B) forming process includes: a coating process of coating a resin layer forming coating liquid onto the light-transmitting substrate (A); and a coating film forming process of drying the coated resin layer forming coating liquid to form a coating film. The coating liquid for forming the resin layer comprises resin, silicon-containing additives, and diluent.

9. The method for manufacturing an optical thin film according to claim 8, wherein, The resin layer (B) forming process further includes a curing process for curing the coating film.

10. The method for manufacturing an optical thin film according to claim 8 or 9, wherein, The optical thin film is the optical thin film according to claim 2 or 3. The silicon-containing additive is the surface conditioner.

11. The method for manufacturing an optical thin film according to claim 8 or 9, wherein, The diluting solvent contains MIBK (methyl isobutyl ketone) and cyclopentanone.

12. An optical component comprising the optical thin film according to any one of claims 1 to 7.

13. The optical component according to claim 12, wherein it is a polarizing plate.

14. An image display device comprising an optical thin film according to any one of claims 1 to 7, or an optical component according to claim 12 or 13.

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