WO2022260152A1

WO2022260152A1 - Hard coat film, optical member, and image display device

Info

Publication number: WO2022260152A1
Application number: PCT/JP2022/023388
Authority: WO
Inventors: 尚樹橋本; 幸大宮本; 岳仁淵田; 裕貴水川; 豊角田; 豪彦安藤
Original assignee: 日東電工株式会社
Priority date: 2021-06-11
Filing date: 2022-06-09
Publication date: 2022-12-15
Also published as: JP2022189597A; KR20240011799A; CN117480412A; TW202313334A

Abstract

Provided is a hard coat film which exhibits both surface wear resistance and bending endurance.　This hard coat film (10) has a hard coat layer (B)(12), an optically functional layer (C)(13), and an anti-fouling layer (D)(14) stacked in this order on at least one surface of a light transmitting base material (A)(11). The anti-fouling layer (D) (14) includes fluorine as an element. The average thickness dS [μm] of the light transmitting base material (A)(11), the average thickness dH [μm] of the hard coat layer (B)(12), and the average thickness dI [μm] of the optically functional layer (C)(13) satisfy the following expressions (1) and (2). (1): 0.2 ≤ dH × dI ≤ 4 (2): 0.02 ≤ (dH + dI)/dS ≤ 0.62

Description

HARD COAT FILM, OPTICAL MEMBER, AND IMAGE DISPLAY DEVICE

The present invention relates to hard coat films, optical members, and image display devices.

A hard coat film is a film in which a hard coat layer is provided on the film surface to increase the surface strength, etc., and is widely used in image display devices (Patent Document 1, etc.).

JP 2008-221746 A

In recent years, there has been an increasing demand for flexible display devices and the like as image display devices. When a hard coat film is used for such applications, not only surface wear resistance but also bending resistance are required.

Accordingly, an object of the present invention is to provide a hard coat film, an optical member, and an image display device that achieve both surface abrasion resistance and bending resistance.

In order to achieve the above object, the hard coat film of the present invention is
A hard coat layer (B), an optical functional layer (C) and an antifouling layer (D) are laminated in the order described above on at least one surface of the light transmissive substrate (A),
The antifouling layer (D) contains fluorine as an element,
The average thicknesses of the light-transmitting substrate (A), the hard coat layer (B) and the optical function layer (C) are characterized by satisfying the following formulas (1) and (2).

0.2≦dH×dI≦4 (1)
0.02≦(dH+dI)/dS≦0.62 (2)

In the above formulas (1) and (2),
dS is the average thickness [μm] of the light transmissive substrate (A),
dH is the average thickness [μm] of the hard coat layer (B),
dI is the average thickness [μm] of the optical function layer (C).

The optical member of the present invention is an optical member containing the hard coat film of the present invention.

The image display device of the present invention is an image display device containing the hard coat film of the present invention or the optical member of the present invention.

According to the present invention, it is possible to provide a hard coat film, an optical member, and an image display device that have both surface abrasion resistance and bending resistance.

FIG. 1 is a cross-sectional view illustrating the configuration of the hard coat film of the present invention. FIG. 2 is a cross-sectional view showing another example of the hard coat film of the present invention. FIG. 3 is a cross-sectional view schematically showing the bending resistance test method of the example.

Next, the present invention will be described more specifically with examples. However, the present invention is not limited in any way by the following description.

In the hard coat film of the present invention, for example, the antifouling layer (D) may have a surface roughness in the range of 1 to 10 nm on the side opposite to the substrate (A).

In the hard coat film of the present invention, for example, the average thickness of the hard coat layer (B) may be in the range of 2 to 12 μm.

In the hard coat film of the present invention, for example, the light-transmitting substrate (A) may have an average thickness of 100 µm or less.

In the hard coat film of the present invention, for example, the antifouling layer (D) may have an average thickness in the range of 1 to 30 nm.

In the hard coat film of the present invention, for example, the hard coat layer (B) may contain at least one selected from the group consisting of organic resin, silicon oxide, titanium oxide and zirconium oxide.

The optical member of the present invention may be, for example, a polarizing plate.

In the image display device of the present invention, for example,
In the hard coat film, the hard coat layer (B), the optical function layer (C) and the antifouling layer (D) are arranged in the order described above on only one side of the light-transmitting substrate (A). laminated,
An adhesive layer is laminated on the other surface of the light-transmitting substrate (A),
The hard coat film may be attached to a member containing glass or a plastic film via the adhesive layer.

In the present invention, "weight" and "mass" may be read interchangeably unless otherwise specified. For example, "parts by weight" may be read as "parts by weight", "parts by weight" may be read as "parts by weight", "mass%" may be read as "% by weight", "% by weight" ” may be read as “% by mass”.

[1. Hard coat film]
The hard coat film of the present invention, as described above,
A hard coat layer (B), an optical functional layer (C) and an antifouling layer (D) are laminated in the order described above on at least one surface of the light transmissive substrate (A),
The antifouling layer (D) contains fluorine as an element,
The average thicknesses of the light-transmitting substrate (A), the hard coat layer (B) and the optical function layer (C) are characterized by satisfying the following formulas (1) and (2).

0.2≦dH×dI≦4 (1)
0.02≦(dH+dI)/dS≦0.62 (2)

In the above formulas (1) and (2),
dS is the average thickness [μm] of the light transmissive substrate (A),
dH is the average thickness [μm] of the hard coat layer (B),
dI is the average thickness [μm] of the optical function layer (C).

[1-1. Configuration of hard coat film, etc.]
The cross-sectional view of FIG. 1 schematically shows an example of the configuration of the hard coat film of the present invention. As shown, the hard coat film 10 includes a hard coat layer (B) 12, an optical function layer (C) 13 and an antifouling layer (D) on at least one surface of a light transmissive substrate (A) 11. 14 are stacked in the above order. The antifouling layer (D) 14 contains fluorine as an element. In the figure, dS is the average thickness [μm] of the light transmissive substrate (A) 11 . dH is the average thickness [μm] of the hard coat layer (B) 12 . dI is the average thickness [μm] of the optical function layer (C) 13 . dF is the average thickness [μm] of the antifouling layer (D) 14 . The average thickness dS [μm] of the light-transmitting substrate (A) 11, the average thickness dH [μm] of the hard coat layer (B) 12, and the average thickness dI [μm] of the optical function layer (C) 13 are calculated according to the above formula It satisfies the relationships (1) and (2).

In addition, in the present invention, "on" or "on the surface" may be in a state of being in direct contact with the surface, or may be in a state of intervening another layer or the like.

Another example of the hard coat film of the present invention is schematically shown in the cross-sectional view of FIG. As shown, the hard coat film 10A comprises a hard coat layer (B) 12, an optical functional layer (C) 13 and an antifouling layer (D) on at least one surface of a light transmissive substrate (A) 11. 14 are stacked in the above order. The antifouling layer (D) 14 contains fluorine as an element. Although the surface of each layer is flat in FIG. 1, unevenness is formed on the surface of the hard coat layer (B) 12 opposite to the light transmissive substrate (A) 11 in FIG. The surfaces of the optical functional layer (C) 13 and the antifouling layer (D) 14 formed on the hard coat layer (B) 12 also have the same uneven shape as the surface of the hard coat layer (B) 12. . Further, in FIG. 2, the hard coat layer (B) 12 contains particles. As illustrated, the hard coat layer (B) 12 is formed by containing particles 12b in a resin layer 12a.

In addition, in the present invention, "on" or "on the surface" may be in a state of being in direct contact with the surface, or may be in a state of intervening another layer or the like. For example, in FIGS. 1 and 2, the light transmissive substrate (A) 11, the hard coat layer (B) 12, the optical function layer (C) 13 and the antifouling layer (D) 14 are directly laminated, which will be described later. It may be laminated via other layers so as to be carried out.

In the hard coat film of the present invention, each of the layers (A) to (D) may be flat as shown in FIG. 1, or may be uneven as shown in FIG.

In the hard coat film of the present invention, the method for measuring the "average thickness" of each layer (A) to (D) is not particularly limited, but for example, linear gauge, TEM (transmission electron microscope), fluorescent X-ray, etc. Specifically, for example, it can be measured by the method described in Examples below. Further, for example, even if the surface of each layer (for example, the hard coat layer (B)) has unevenness and the thickness of each part varies, for example, any three points can be detected by imaging in a 1 μm square field of view. The thickness is measured, and the thickness is measured at 5 points in a 1 μm square visual field in the same manner, and the average value of the thickness measurement results at 15 points in total is taken as the average thickness, whereby the average thickness can be measured.

As described above, the hard coat film of the present invention satisfies the following formula (1). That is, the product of the average thickness dH [μm] of the hard coat layer (B) and the average thickness dI [μm] of the optical function layer (C) is in the range of 0.2-4.

0.2≦dH×dI≦4 (1)

When the product dH×dI of the average thickness dH [μm] of the hard coat layer (B) and the average thickness dI [μm] of the optical function layer (C) is less than 0.2, the mechanical strength of the hard coat film decreases, resulting in insufficient wear resistance. If dH [μm]×dI [μm] exceeds 4, the hard coat film becomes too hard and lacks toughness, resulting in insufficient bending resistance, which may cause breakage of the hard coat film when bent. dH [μm]×dI [μm] may be, for example, 0.2 or more, 0.3 or more, 0.4 or more, or 0.5 or more, for example, 4.0 or less, 3.5 or less , 3.0 or less, or 2.5 or less, for example, 0.2 to 4.0, 0.3 to 3.5, 0.4 to 3.0, or 0.5 to 2.0. 5 may be used.

As described above, the hard coat film of the present invention satisfies the following formula (2). That is, the average thickness dH [μm] of the hard coat layer (B) and the average thickness dH [μm] of the hard coat layer (B) are added to the average thickness dS [μm] of the light-transmitting substrate (A). ] is in the range of 0.02 to 0.62.

0.02≦(dH+dI)/dS≦0.62 (2)

(dH [μm] + dI [μm]) / dS [μm] is less than 0.02, in the hard coat film, the thickness of the hard coat layer (B) that ensures hardness and the optical function layer ( The ratio of the thickness of the light-transmitting substrate (A), which has a lower elastic modulus than the hard coat layer (B) and the optical function layer (C), to the total thickness of C) is too large. means In such a case, members having weak strength occupy most of the composition of the entire hard coat film, resulting in low abrasion resistance. On the other hand, if (dH[μm]+dI[μm])/dS[μm] exceeds 0.62, the portion with high hardness accounts for too large a proportion of the entire hard coat film, resulting in low bending resistance. (dH [μm] + dI [μm])/dS [μm] may be, for example, 0.02 or more, 0.03 or more, 0.04 or more, or 0.05 or more, for example, 0.6 0.5 or less, 0.4 or less, or 0.3 or less, for example, 0.02 to 0.6, 0.03 to 0.5, 0.04 to 0.4, or It may be from 0.05 to 0.3.

In addition, the hard coat film of the present invention contains layers other than the light transmissive substrate (A), the hard coat layer (B), the optical function layer (C) and the antifouling layer (D). It may or may not contain For example, the light-transmitting substrate (A), the hard coat layer (B), the optical function layer (C), and the antifouling layer (D) may be directly laminated. You may laminate|stack via other layers, such as a layer. Further, for example, another layer may or may not be laminated on the outside of the antifouling layer (D).

In addition, in the present invention, "adhesive layer" means "adhesive layer or adhesive layer". "Adhesive layer" means "a layer formed by an adhesive". "Adhesive layer" means "a layer formed by an adhesive". In general, an adhesive that has a relatively small adhesive force (adhesive force) and can be removed from the adherend is called an "adhesive", and has a relatively large adhesive force (adhesive force) that makes it impossible to remove the adherend. Difficult things are sometimes called "adhesives" to distinguish them. In the present invention, a substance with a relatively small adhesive force (adhesive force) is called an "adhesive", and a substance with a relatively large adhesive force (adhesive force) is called an "adhesive", but there is no clear distinction between the two. .

The adhesive layer may be, for example, an adhesive layer formed of an adhesive (adhesive composition). The thickness of the adhesive layer is not particularly limited. may be Although the adhesive is not particularly limited, examples thereof include (meth)acrylic polymers. For example, these may be dissolved or dispersed in a solvent to form a solution or dispersion, which may be used as the pressure-sensitive adhesive (pressure-sensitive adhesive composition). Examples of the solvent include ethyl acetate and the like, and one type thereof may be used alone, or a plurality of types may be used in combination. The concentration of the solute or dispersoid (e.g., the acrylic polymer) in the solution or dispersion may be, for example, 10% by mass or more, or 15% by mass or more, for example, 60% by mass or less, or 50% by mass. % or less, 40 mass % or less, or 25 mass % or less. In the present invention, "(meth)acrylic polymer" refers to a polymer or copolymer of at least one monomer selected from (meth)acrylic acid, (meth)acrylic acid ester, and (meth)acrylamide. In the present invention, (meth)acrylic acid means "at least one of acrylic acid and methacrylic acid", and "(meth)acrylic acid ester" means "at least one of acrylic acid ester and methacrylic acid ester". means. Examples of the (meth)acrylic acid ester include linear or branched alkyl esters of (meth)acrylic acid. In the linear or branched alkyl ester of (meth)acrylic acid, the number of carbon atoms in the alkyl group may be, for example, 1 or more, 2 or more, 3 or more, or 4 or more, for example, 18 or less, 16 or less. , 14 or less, 12 or less, 10 or less, or 8 or less. Said alkyl groups may be substituted or unsubstituted, for example with one or more substituents. Examples of the substituents include hydroxyl groups and the like, and in the case of a plurality of substituents, they may be the same or different. Specific examples of the (meth)acrylic acid ester include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate and the like. Moreover, the said adhesive may use only one type, and may use multiple types together.

Next, each of the layers (A) to (D) will be described with examples.

[1-2. Light-transmitting substrate (A)]
The light-transmitting substrate (A) is not particularly limited. A base material etc. are mentioned. The transparent plastic film substrate is not particularly limited, but preferably has excellent visible light transmittance (preferably light transmittance of 90% or more) and excellent transparency (preferably haze value of 1% or less). , for example, a transparent plastic film substrate described in JP-A-2008-90263. As the transparent plastic film substrate, one having optically low birefringence is preferably used. The hard coat film of the present invention can also be used for a polarizing plate as a protective film, for example. A film formed of polyolefin or the like having a or norbornene structure is preferable. Moreover, in the present invention, the transparent plastic film substrate may be the polarizer itself. Such a structure eliminates the need for a protective layer made of TAC or the like and simplifies the structure of the polarizing plate, thereby reducing the number of steps for manufacturing the polarizing plate or the image display device and improving the production efficiency. Moreover, with such a configuration, the polarizing plate can be made thinner. When the transparent plastic film substrate is a polarizer, for example, the non-transparent layer functions as a protective layer. Further, with such a structure, the hard coat film of the present invention also functions as a cover plate, for example, when attached to the surface of a liquid crystal cell.

In the present invention, the average thickness of the light-transmitting substrate (A) is not particularly limited. 100 μm or less, such as 90 μm or less, 80 μm or less, 70 μm or less, or 60 μm or less, for example, 10-100 μm, 20-90 μm, 30-80 μm, 40-70 μm, or 50 μm or less. It may be 60 μm. From the viewpoints of ensuring workability and bending resistance, it is preferable that the average thickness of the light-transmitting substrate (A) is not too large. From the viewpoint of insufficient strength, it is preferable that the average thickness of the light-transmitting substrate (A) is not too small. The method for measuring the average thickness of the light-transmitting substrate (A) is not particularly limited, but for example, it can be measured using a linear gauge as in Examples described later.

The refractive index of the light transmissive substrate (A) is not particularly limited. The refractive index ranges, for example, from 1.30 to 1.80 or from 1.40 to 1.70.

In the present invention, "refractive index" refers to the refractive index at a wavelength of 550 nm unless otherwise specified. Moreover, in the present invention, the method for measuring the refractive index is not particularly limited, but in the case of the refractive index of fine substances such as particles, for example, the Becke method can be used. In the Becke method, a sample to be measured is dispersed in a standard refractive liquid on a slide glass, and the refractive index of the standard refractive liquid when the outline of the sample disappears or becomes blurred when observed with a microscope is used as the refractive index of the sample. It is a measurement method that In addition, the method for measuring the refractive index of a measurement object whose refractive index cannot be measured by the Becke method (for example, an antiglare film, an antiglare layer, or a resin constituting an antiglare layer, etc.) is not particularly limited, but for example, It can be measured using a general refractometer (instrument for measuring refractive index). The refractometer is also not particularly limited, and examples thereof include an Abbe refractometer. Examples of the Abbe refractometer include a multi-wavelength Abbe refractometer DR-M2/1550 (trade name) manufactured by Atago Co., Ltd.

[1-3. Hard coat layer (B)]
The hard coat layer (B) is not particularly limited, and may be, for example, similar to or similar to a hard coat layer of a general hard coat film. For example, the hard coat layer (B) may be formed of a resin layer. Further, for example, the hard coat layer (B) may or may not contain fillers, thixotropy-imparting agents, surface control agents, pigments, dyes, and the like. Although the filler is not particularly limited, it may be, for example, particles. The particles are not particularly limited, and may be, for example, organic particles or inorganic particles, and may be amorphous particles or spherical particles. The material for forming the hard coat layer (B) will be described later in detail.

In the present invention, the average thickness of the hard coat layer (B) is not particularly limited. for example, 30 μm or less, 25 μm or less, 20 μm or less, 15 μm or less, or 10 μm or less, for example, 0.5-30 μm, 1.0-25 μm, 101.5-20 μm, 2.0 μm or less. ˜15 μm, or 2.5-10 μm. From the viewpoint of preventing curling and processing defects, it is preferable that the average thickness of the hard coat layer (B) is not too large. From the viewpoint of preventing a decrease in pencil hardness and insufficient hardness, it is preferable that the average thickness of the hard coat layer (B) is not too small. The method for measuring the average thickness of the hard coat layer (B) is not particularly limited, but for example, it can be measured using a linear gauge as in Examples described later.

In the present invention, the surface roughness of the surface of the hard coat layer (B) opposite to the substrate (A) is not particularly limited, but is, for example, 1 nm or more, 1.5 nm or more, or 2.0 nm or more. , 2.5 nm or more, or 3.0 nm or more, for example, 10 nm or less, 9.5 nm or less, 9.0 nm or less, 8.5 nm or less, or 8.0 nm or less, for example, It may be 1-10 nm, 1.5-9.5 nm, 2.0-9.0 nm, 2.5-8.5 nm, or 3.0-8.0 nm. In the following, unless otherwise specified, the "surface roughness" of each layer of the hard coat film of the present invention refers to the surface roughness on the side opposite to the substrate (A). The surface roughness of the hard coat layer (B) affects, for example, the adhesion between the hard coat layer (B) and the optical function layer (C). From the viewpoint of preventing haze and scratching of the surface, it is preferable that the surface roughness of the hard coat layer (B) is not too large. From the viewpoint of preventing poor adhesion with the optical function layer (C) and preventing deterioration of antiblocking properties, it is preferable that the surface roughness of the hard coat layer (B) is not too small.

In the present invention, the method for measuring the surface roughness Ra of each layer of the hard coat film is not particularly limited, but it can be measured, for example, by the following measuring method. In the hard coat film of the present invention, when the surface roughness of the outermost layer is measured, the surface roughness of the layer below it can be generally estimated to be approximately equal to the surface roughness of the outermost layer. When no other layer is formed on the antifouling layer (D), the antifouling layer (D) is the outermost layer. For example, when the antifouling layer (D) is the outermost layer, if the surface roughness of the antifouling layer (D) is measured, usually the optical functional layer (C) and the hard coat layer (B) can be estimated to be approximately equal to the measured value of the surface roughness of the antifouling layer (D).

[Method for measuring surface roughness Ra]
The surface of the antifouling layer (D) in the hard coat film of the present invention was observed with an atomic force microscope (trade name “SPI3800”, manufactured by Seiko Instruments Inc.). (Arithmetic mean roughness) is calculated.

[1-4. Optical functional layer (C)]
The optical function layer (C) may be, for example, an antireflection layer having an antireflection function. Also, the optical function layer (C) may be an inorganic layer formed of an inorganic substance, for example. In addition, in the present invention, the “inorganic substance” includes, for example, an organic-inorganic hybrid material described later. The inorganic substance that is the material for forming the optical function layer (C) is not particularly limited, but may contain, for example, at least one selected from the group consisting of metals, metal oxides, silicon and silicon oxides. . The optical functional layer (C) will be described below with reference to examples.

In the optical function layer (C), the metal is not particularly limited, but examples thereof include aluminum, zinc, tin, indium, gallium, zirconium, lead and the like. The metal oxide is not particularly limited, but for example, aluminum oxide (eg, Al ₂ O ₃ ), zinc-tin composite oxide (ZTO), indium-tin composite oxide (ITO), indium-zinc composite oxide (IZO), Gallium-zinc composite oxide (GZO), zirconium oxide (ZrO ₂ ), and the like are included. In the present invention, the silicon oxide is, for example, a compound represented by SiOx (0<x≦2). Examples of the silicon oxide include, but are not limited to, silicon dioxide (SiO ₂ ).

The material for forming the optical functional layer (C) is not particularly limited, and may be the same as the optical functional layer in a general optical film (eg, hard coat film). For example, when the optical function layer (C) is an antireflection layer, the material for forming it may be the same as that of a general antireflection layer. For example, when the optical function layer (C) is an inorganic layer, the material for forming the layer may be the same as for general inorganic layers. Further, the optical function layer (C) may consist of only one layer, or may consist of a plurality of layers. Each layer of the optical function layer (C) may be made of only one type of forming material, or may be made of a plurality of types of forming materials. For example, the optical function layer (C) may be a laminate of an adhesion layer and another layer. Specifically, for example, in order to increase the adhesion between the hard coat layer (B) and the other layer, first, the adhesion layer is formed on the hard coat layer (B), and then The other layers may be formed. The adhesion layer may be, for example, an ITO layer. ITO has a high refractive index and absorbs light easily, so if the thickness of the ITO layer is too large, for example, antireflection performance may decrease. Therefore, when the optical function layer (C) is an antireflection layer, it is preferable not to increase the thickness of the ITO layer too much.

The optical function layer (C) may contain, for example, an organic-inorganic hybrid material. The organic-inorganic hybrid material is not particularly limited, but examples thereof include polysiloxane resins and silsesquioxane resins. Further, the optical function layer (C) may or may not contain, for example, components other than the inorganic substance. Said other component may be, for example, an organic compound. The organic compound is not particularly limited, but may be, for example, various resins. Although the resin is not particularly limited, for example, it may be the same as the resin that can be used as the material for forming the light-transmitting base material (A), and one type of resin may be used alone or a plurality of types may be used in combination. The resin may be, for example, an acrylic resin or the like. For example, the optical function layer (C) may be formed of a mixture of acrylic resin and zirconium oxide, a mixture of acrylic resin and silicon oxide (silica), or the like. When the optical function layer (C) contains the other component, the content is not particularly limited, but may be, for example, 10% by mass or less, 5% by mass or less, or 1% by mass or less. is not particularly limited, but is, for example, a numerical value exceeding 0% by mass.

A method for forming the optical function layer (C) is not particularly limited, but a so-called dry process (a forming method that does not use a solvent) is preferable. Specifically, for example, it may be formed by at least one method selected from the group consisting of vacuum deposition, sputtering, and chemical vapor deposition (CVD). Specific methods for vacuum deposition, sputtering, and chemical vapor deposition (CVD) are also not particularly limited, and may be, for example, the same or similar to general methods.

The method for forming the optical function layer (C) of the present invention is not particularly limited. For example, using an inorganic substance, the optical function layer (C) having a certain thickness or more is formed by at least one method selected from the group consisting of vacuum deposition, sputtering, and chemical vapor deposition (CVD). By forming, the optical function layer (C) of the present invention can be formed. The inorganic substance is not particularly limited, but may contain, for example, at least one material selected from the group consisting of metals, metal oxides, silicon and silicon oxides, as described above.

The average thickness of the optical function layer (C) is not particularly limited. For example, it may be 0.5 μm or less, 0.4 μm or less, 0.3 μm or less, 0.2 μm or less, or 0.1 μm or less, such as 0.05 to 0.5 μm, 0.06 to 0.4 μm. , 0.07-0.3 μm, 0.08-0.2 μm, or 0.09-0.1 μm. From the viewpoint of preventing deterioration of bending resistance, it is preferable that the average thickness of the optical function layer (C) is not too large. From the viewpoint of preventing deterioration of sliding resistance, it is preferable that the average thickness of the optical function layer (C) is not too small. Although the method for measuring the average thickness of the optical function layer (C) is not particularly limited, for example, it can be measured using a TEM (transmission electron microscope) as in Examples described later.

In the present invention, the surface roughness of the optical function layer (C) is not particularly limited, but is, for example, the same as the surface roughness of the hard coat layer (B). Moreover, from the viewpoint of preventing haze and scratching of the surface, it is preferable that the surface roughness of the optical function layer (C) is not too large. From the viewpoint of preventing poor adhesion with the antifouling layer (D) and preventing deterioration of antiblocking properties, it is preferable that the surface roughness of the optical function layer (C) is not too small.

[1-5. Antifouling layer (D)]
The antifouling layer (D) is not particularly limited, but may be, for example, similar to or conforming to an antifouling layer used in general optical members and the like. The antifouling layer (D) contains fluorine as an element as described above. Specifically, for example, the antifouling layer (D) may contain at least one of elemental fluorine and a fluorine compound as an antifouling component. Examples of the antifouling component include, but are not particularly limited to, an organic silane compound having a perfluoropolyether group. In addition, the antifouling layer (D) may or may not contain components other than the antifouling component. When the antifouling layer (D) contains the other component, the content is not particularly limited, but is, for example, 50% by mass or less, 25% by mass or less, 20% by mass or less, 10% by mass or less, 5% by mass. % or less, or 1% by mass or less, and the lower limit is not particularly limited, but it is, for example, a numerical value exceeding 0% by mass.

By containing fluorine as an element, the antifouling layer (D) can exhibit high antifouling properties even with a small film thickness, for example, so that the optical function of the optical function layer (C) is less likely to be impaired. The optical function of the optical function layer (C) includes, for example, an antireflection function. In addition, since the antifouling layer (D) contains fluorine as an element, for example, a low refractive index can be realized, and the refractive index difference with the optical function layer (C) is reduced. Accordingly, for example, the antifouling layer (D) is less likely to change the reflection spectrum of the optical function layer (C), and less likely to impede the optical function (for example, antireflection function) of the optical function layer (C). When compared with antifouling layers such as titanium oxide, the antifouling layer (D) in the present invention can achieve, for example, a low refractive index as described above. In addition, it is difficult to form an antifouling layer of titanium oxide or the like by a method other than a dry process (a forming method that does not use a solvent). Therefore, if the thickness of the antifouling layer is large, there is a possibility that the productivity will be low. On the other hand, the antifouling layer (D) in the present invention can be formed (formed) by various methods such as wet coating and vapor deposition, depending on the material used to form the layer. The forming method is not limited.

The method for forming the antifouling layer (D) is not particularly limited as described above, but a so-called dry process (a forming method that does not use a solvent) is preferred. Specifically, for example, it may be formed by at least one method selected from the group consisting of vacuum deposition, sputtering, and chemical vapor deposition (CVD). Specific methods for vacuum deposition, sputtering, and chemical vapor deposition (CVD) are also not particularly limited, and may be, for example, the same or similar to general methods.

The average thickness of the antifouling layer (D) is not particularly limited, but may be, for example, 1 nm or more, 2 nm or more, 3 nm or more, 4 nm or more, or 5 nm or more. , 24 nm or less, or 22 nm or less, for example, 1-30 nm, 2-28 nm, 3-26 nm, 4-24 nm, or 5-22 nm. From the viewpoint of preventing film detachment (peeling of the antifouling layer (D)), it is preferable that the average thickness of the antifouling layer (D) is not too large. From the viewpoint of preventing deterioration of wear resistance and antifouling properties, it is preferable that the average thickness of the antifouling layer (D) is not too small. Although the method for measuring the average thickness of the antifouling layer (D) is not particularly limited, for example, it can be measured using fluorescent X-rays as in Examples described later.

In the present invention, the surface roughness of the antifouling layer (D) is not particularly limited. for example, 10 nm or less, 9.5 nm or less, 9.0 nm or less, 8.5 nm or less, or 8.0 nm or less, for example, 1 to 10 nm, 1.5 to 9.5 nm , 2.0-9.0 nm, 2.5-8.5 nm, or 3.0-8.0 nm. A method for measuring the surface roughness is not particularly limited, and is, for example, as described above. From the viewpoints of preventing haze and susceptibility to scratches, it is preferable that the surface roughness of the antifouling layer (D) is not too large. From the viewpoint of antiblocking properties, it is preferable that the surface roughness of the antifouling layer (D) is not too small.

In the present invention, the water contact angle of the antifouling layer (D) surface (the surface on the side opposite to the substrate (A)) is not particularly limited. ° or more, 110° or more, or 115° or more. From the viewpoint of antifouling performance, it is preferable that the water contact angle of the antifouling layer (D) is not too large.

[1-6. others]
The hard coat film of the present invention can be used, for example, as a clear film or an antiglare film (also called AG film). For example, in order to use it as an antiglare film, the hard coat layer (B) may be provided with antiglare properties (AG properties).

The hard coat film of the present invention may have, for example, a light transmittance of 90% or more at a wavelength of 550 nm for the entire hard coat film. The light transmittance of the entire hard coat film at a wavelength of 550 nm is, for example, 90% or more, 92% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more. for example, 100% or less, 99% or less, 98% or less, 97% or less, 96% or less, 95% or less, 94% or less, 93% or less, 92% or less, or even 90% or less well, for example, 90-100%, 90-99%, 90-98%, 90-97%, 90-96%, 90-95%, 90-94%, 90-93%, 90-92%, 92 ~100%, 92-99%, 92-98%, 92-97%, 92-96%, 92-95%, 92-94%, 92-93%, 94-100%, 94-99%, 94 ~98%, 94-97%, 94-96%, 94-95%, 95-100%, 95-99%, 95-98%, 95-97%, 95-96%, 96-100%, 96 It may be ~99%, 96-98%, 96-97%, 97-100%, 97-99%, 97-98%, 98-100%, 98-99%, or 99-100%. Due to the high light transmittance of the entire hard coat film, there are advantages such as not impairing the brightness when made into a polarizing plate, and easy appearance inspection due to high transparency.

In addition, in the present invention, the method for measuring the light transmittance is not particularly limited, but it can be measured, for example, by the following measuring method.

[Method for measuring light transmittance]
・Apparatus: Integrating sphere type spectral transmittance measuring instrument (product name: DOT-3C, manufactured by Murakami Color Research Laboratory)
・Measurement mode: total light transmittance & color calculation ・Light source: D65 light source ・Viewing angle: 2 degree field of view .

[2. Method for producing hard coat film]
The method for producing the hard coat film of the present invention is not particularly limited, and for example, it can be carried out in the same manner as or according to a general method for producing a hard coat film. The method for producing the hard coat film of the present invention will be described below with reference to examples.

First, a light-transmitting substrate (A) is prepared. The material, thickness, etc. of the light-transmitting substrate (A) are, for example, as described above.

Next, a hard coat layer (B) is formed on the light transmissive substrate (A). The method for forming the hard coat layer (B) on the light-transmitting substrate (A) is not particularly limited, but is, for example, as follows. Hereinafter, the step of forming this hard coat layer (B) may be referred to as a "hard coat layer forming step". In the hard coat layer forming step, for example, a coating solution for forming a hard coat layer (hereinafter sometimes simply referred to as "coating solution" or "hard coat layer forming material") is applied onto the light-transmitting substrate (A). ) and a coating film forming step of drying the applied coating liquid to form a coating film. Further, for example, the hard coat layer forming step may further include a curing step of curing the coating film. The curing can be performed after the drying, for example, but not limited thereto. The curing can be performed, for example, by heating, light irradiation, or the like. Although the light is not particularly limited, it may be, for example, ultraviolet light. The light source for the light irradiation is also not particularly limited, and may be, for example, a high-pressure mercury lamp.

The coating liquid (hard coat layer forming material) may be, for example, a coating liquid containing a resin material and a diluent solvent (hereinafter sometimes simply referred to as "solvent"). Moreover, the coating liquid may or may not contain components other than these. Examples of the other components include, but are not limited to, thixotropy-imparting agents and fillers. Examples of the filler include particles. The particles are not particularly limited, and may be, for example, organic particles or inorganic particles, and may be amorphous particles or spherical particles. The thixotropic agent, the particles, and the like are not particularly limited, but may be, for example, the same as or similar to the thixotropic agent, particles, and the like contained in a general hard coat layer. Examples of the particles include acrylic-styrene copolymers, silicone resins, and silica.

The resin material contained in the coating liquid may be, for example, the resin itself that forms the hard coat layer (B), or may be a resin material that forms the resin through polymerization, curing, or the like. The resin is not particularly limited, but may be, for example, a thermosetting resin, an ionizing radiation curable resin, or the like. Further, the resin may contain, for example, an acrylate resin (also referred to as acrylic resin), and may contain, for example, a urethane acrylate resin. Further, the resin may be, for example, a copolymer of a curable urethane acrylate resin and a polyfunctional acrylate.

The resin material may contain, for example, an oligomer having a functional group and a monomer. For example, the resin forming the hard coat layer (B) may be a copolymer of the oligomer having the functional group and the monomer. Examples of the oligomer having the functional group include, but are not particularly limited to, curable urethane acrylate resins. Examples of the curable urethane acrylate resin include "UV-1700TL" (trade name) manufactured by Mitsubishi Chemical Corporation, "UT-7314" (trade name) manufactured by Mitsubishi Chemical Corporation, and the like. Examples of the monomer include, but are not limited to, polyfunctional acrylates. Examples of the polyfunctional acrylate include trade name "M-920" manufactured by Toagosei Co., Ltd., and the like.

The solvent is not particularly limited, and various solvents can be used. One type may be used alone, or two or more types may be used in combination. For example, the optimum solvent type and solvent ratio may be appropriately selected according to the composition of the resin, the types and contents of the nanosilica particles and the thixotropy-imparting agent. Examples of the solvent include, but are not limited to, alcohols such as methanol, ethanol, isopropyl alcohol (IPA), butanol, t-butyl alcohol (TBA), 2-methoxyethanol; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclo ketones such as pentanone; 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; cellosolves such as ethyl cellosolve and butyl cellosolve ; aliphatic hydrocarbons such as hexane, heptane and octane; and aromatic hydrocarbons such as benzene, toluene and xylene. Further, for example, the solvent may contain a hydrocarbon solvent and a ketone solvent. Said hydrocarbon solvent may be, for example, an aromatic hydrocarbon. The 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 ketone solvent may be, for example, cyclopentanone and at least one selected from the group consisting of acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, cyclohexanone, isophorone, and acetophenone. The solvent preferably contains the hydrocarbon solvent (eg, toluene), for example, in order to dissolve the thixotropic agent (eg, thickener). The solvent may 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 and the ketone solvent may be, for example, 80:20-20:80, 70:30-30:70, or 40:60-60:40. In this case, for example, the hydrocarbon solvent may be toluene and the ketone solvent may be methyl ethyl ketone. In addition, the solvent may contain, for example, toluene, and may further contain at least one selected from the group consisting of ethyl acetate, butyl acetate, IPA, methyl isobutyl ketone, methyl ethyl ketone, methanol, ethanol, and TBA. good.

For example, when an acrylic film is used as the light-transmitting substrate (A) to form the intermediate layer (permeation layer), a good solvent for the acrylic film (acrylic resin) can be suitably used. The solvent may be, for example, a solvent containing a hydrocarbon solvent and a ketone solvent, as described above. Said hydrocarbon solvent may be, for example, an aromatic hydrocarbon. The 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 ketone solvent may be, for example, at least one selected from the group consisting of cyclopentanone, acetone, methylethylketone, methylisobutylketone, diethylketone, cyclohexanone, isophorone, and acetophenone. The solvent may 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 and the ketone solvent may be, for example, 80:20-20:80, 70:30-30:70, or 40:60-60:40. In this case, for example, the hydrocarbon solvent may be toluene and the ketone solvent may be methyl ethyl ketone.

For example, when triacetyl cellulose (TAC) is used as the light-transmitting substrate (A), the solvent is not particularly limited, but examples include ethyl acetate, methyl ethyl ketone, MIBK (methyl isobutyl ketone), and cyclopentanone. etc., and one type may be used alone or a plurality of types may be used in combination. In this case, the solvent may be, for example, a mixed solvent of MIBK and cyclopentanone. The mixing ratio of MIBK and cyclopentanone is not particularly limited, but may be, for example, 90:10 to 10:90, 80:20 to 20:80, 70:30 to 30:70 in mass ratio.

In addition, by appropriately selecting the solvent, it is possible to exhibit good thixotropic properties in the antiglare hard coat layer-forming material (coating liquid) when the thixotropy-imparting agent is contained. For example, when using organoclays, toluene and xylene can be suitably used alone or in combination. They can be used or used in combination. For example, when modified urea is used, butyl acetate and methyl isobutyl ketone can be preferably used alone or in combination.

Various leveling agents can be added to the hard coat layer forming material. As the leveling agent, for example, a fluorine-based or silicone-based leveling agent can be used for the purpose of preventing coating unevenness (uniformizing the coated surface). In the present invention, when antifouling property is required on the surface of the hard coat layer, or when the other layer antireflection layer (low refractive index layer) or layer containing an interlayer filler is formed on the hard coat layer. A suitable leveling agent can be selected according to the requirements.

The amount of the leveling agent compounded is, for example, 5 parts by weight or less, preferably in the range of 0.01 to 5 parts by weight, per 100 parts by weight of the resin.

Pigments, fillers, dispersants, plasticizers, UV absorbers, surfactants, antifouling agents, antioxidants, and the like are added to the hard coat layer-forming material as necessary within a range that does not impair the performance. may be These additives may be used singly or in combination of two or more.

Conventionally known photopolymerization initiators, such as those described in JP-A-2008-88309, can be used for the hard coat layer-forming material.

Examples of the method for forming a coating film by coating the hard coat layer-forming material (coating solution) on the light-transmitting substrate (A) include a fountain coating method, a die coating method, a spray coating method, and a gravure coating method. A coating method such as a coating method, a roll coating method, or a bar coating method can be used.

Next, as described above, the coating film is dried and cured to form a hard coat layer (B). The drying may be, for example, natural drying, air drying by blowing air, heat drying, or a combination thereof.

The drying temperature of the hard coat layer forming material (coating liquid) may be, for example, in the range of 30 to 200°C. The drying temperature may be, for example, 40° C. or higher, 50° C. or higher, 60° C. or higher, 70° C. or higher, 80° C. or higher, 90° C. or higher, or 100° C. or higher, 190° C. or lower, 180° C. or lower, 170° C. °C or lower, 160 °C or lower, 150 °C or lower, 140 °C or lower, 135 °C or lower, 130 °C or lower, 120 °C or lower, or 110 °C or lower. The drying time is not particularly limited. may

The means for curing the coating film is not particularly limited, but ultraviolet curing is preferable. The irradiation amount of the energy beam source is preferably 50 to 500 mJ/cm ² as an integrated exposure amount at an ultraviolet wavelength of 365 nm. When the irradiation dose is 50 mJ/cm ² or more, curing proceeds sufficiently and the hardness of the formed hard coat layer tends to increase. Moreover, if it is 500 mJ/cm ² or less, coloring of the formed hard coat layer can be prevented.

As described above, a laminate in which the hard coat layer (B) is laminated on the light-transmitting substrate (A) can be produced.

Next, an optical functional layer (C) is formed on the surface of the hard coat layer (B) opposite to the light transmissive substrate (A) (optical functional layer forming step). The method for forming the optical function layer (C) in this optical function layer forming step is not particularly limited, but dry processes are preferred as described above, and examples include vacuum deposition, sputtering, and chemical vapor deposition (CVD). may be formed by at least one method selected from the group consisting of Specific methods for vacuum deposition, sputtering, and chemical vapor deposition (CVD) are also not particularly limited, and may be, for example, the same or similar to general methods. The material, thickness, etc. of the optical function layer (C) are, for example, as described above. Further, for example, prior to the optical functional layer forming step of forming the optical functional layer (C), the hard coating layer (B) may be formed in order to increase the adhesion between the hard coating layer (B) and the optical functional layer (C). The surface may be surface-treated by methods such as plasma treatment, corona treatment, water washing treatment, and solvent coating. Conditions for this surface treatment are also not particularly limited, and may be, for example, similar to or in conformity with general front surface treatment.

In the "hard coat layer forming step" and the "optical functional layer forming step", the average thickness of the light transmissive substrate (A), the hard coat layer (B) and the optical functional layer (C) is A hard coat layer (B) and an optical function layer (C) are formed so as to satisfy the relationships (1) and (2).

Furthermore, an antifouling layer (D) is further formed on the surface of the optical functional layer (C) opposite to the light-transmissive substrate (A) (antifouling layer forming step) to obtain the hard coat film of the present invention. can be manufactured. The method (manufacturing method) for forming the antifouling layer (D) in this antifouling layer forming step is not particularly limited, but may be, for example, similar to or conforming to a general antifouling layer forming method. Specifically, for example, as described above, it can be formed by a dry process, such as a vacuum deposition method, a sputtering method, a chemical vapor deposition method (CVD), or the like. This method is not particularly limited, and for example, as described above, it may be similar to or based on general vacuum deposition methods, sputtering methods, and chemical vapor deposition methods (CVD). The material, thickness, etc. of the antifouling layer (D) are, for example, as described above.

As described above, the hard coat layer (B), the optical functional layer (C) and the antifouling layer (D) are laminated in the order described above on at least one surface of the light transmissive substrate (A). Inventive hardcoat films can be produced. However, as described above, this production method is an example, and the production method of the hard coat film of the present invention is not limited to this.

Also, the method for producing the hard coat film of the present invention can be, for example, a continuous production method. Specifically, for example, in the method for producing a hard coat film of the present invention, the light-transmissive substrate (A) is elongated, and the hard coat film is conveyed while the light-transmissive substrate (A) is conveyed. The manufacturing method may be such that the coating layer forming step, the optical function layer forming step, the antifouling layer forming step, and, if necessary, other steps are performed continuously. More specifically, for example, the long light-transmitting substrate (A) is in the form of a roll, and the method for producing the hard coat film of the present invention while unwinding the light-transmitting substrate (A) from the roll. may be implemented.

[3. Hard coat film, optical member, and image display device]
The hard coat film of the present invention is not particularly limited. For example, as described above, it may be a clear film or an antiglare film (antiglare hard coat film).

Although the optical member of the present invention is not particularly limited, it may be, for example, a polarizing plate. The polarizing plate is also not particularly limited, but may contain, for example, the hard coat film and polarizer of the present invention, and may further contain other constituent elements. Each constituent element of the polarizing plate may be bonded together by, for example, an adhesive or a pressure-sensitive adhesive.

The image display device of the present invention is also not particularly limited, and may be any image display device, such as a liquid crystal display device, an organic EL display device, an inorganic EL display device, a plasma display device, and the like.

The configuration of the image display device of the present invention is not particularly limited, and may have, for example, the same configuration as a general image display device. For example, an LCD can be manufactured by appropriately assembling components such as a liquid crystal cell, optical members such as a polarizing plate, and, if necessary, an illumination system (backlight, etc.) and incorporating a drive circuit.

The application of the image display device of the present invention is not particularly limited, and can be used for any application. Applications include, for example, personal computer monitors, laptop computers, tablets, smartphones, OA equipment such as copiers, mobile phones, clocks, digital cameras, personal digital assistants (PDAs), portable equipment such as portable game machines, video cameras, Household electrical equipment such as televisions and microwave ovens, back monitors, car navigation system monitors, car audio equipment, display equipment such as information monitors for commercial stores, security equipment such as surveillance monitors, nursing care monitors , nursing and medical equipment such as medical monitors, smart glasses, and VR equipment. The image display device of the present invention may be, for example, an image display device having a camera function. In that case, for example, as described above, the transparent layer in the hard coat film of the present invention may be a transparent layer for a camera hole of an image display device. According to the present invention, as described above, it is possible to provide a hard coat film without impairing the transparency of the transparent layer. Therefore, for example, it is possible to provide an image display device without impairing the image quality of camera images. be.

Next, examples of the present invention will be described together with comparative examples. However, the present invention is not limited by the following examples and comparative examples.

In addition, in the following examples and comparative examples, the number of parts of substances is parts by mass (parts by weight) unless otherwise specified.

[Example 1]
According to the present invention, a hard coat layer (B), an optical functional layer (C) and an antifouling layer (D) are laminated in the order described above on one surface of a light transmissive substrate (A) in the following manner. of the hard coat film was produced.

First, a polyethylene terephthalate (PET) film (thickness: 65 μm) was prepared as the light-transmitting substrate (A). Next, a hard coat layer (B) was formed on one surface of the light transmissive substrate (A) (hard coat layer forming step). Specifically, first, a mixture of UV-curable monomer and SiO ₂ filler (trade name “OPSTAR Z7540”, solid content concentration 56% by mass, manufactured by Arakawa Chemical Industries, Ltd.) 100 parts by mass (solid content conversion), light A polymerization initiator (trade name “IRGACURE906”, manufactured by BASF) 5 parts by mass and a leveling agent (trade name “LE-303”, manufactured by Kyoeisha Chemical Co., Ltd.) 0.1 part by mass are mixed to obtain a mixed solution. rice field. A mixed solvent of butyl acetate and MIBK (mass ratio: 50:50) was added to the mixture to adjust the solid content concentration to 40%. Thus, an ultraviolet curable resin composition (varnish) was prepared. The resin composition was applied to one side of the PET film (light-transmitting substrate (A)) to form a coating film. This coating film was dried by heating and then cured by UV irradiation. The temperature for heating the coating film was 70° C., and the heating time was 60 seconds. In the ultraviolet irradiation, a high-pressure mercury lamp was used as a light source, ultraviolet rays with a wavelength of 365 nm were used, and the cumulative irradiation light amount was set at 300 mJ/cm ² . As described above, a hard coat layer (B) having a thickness of 5 μm is formed on the PET film (light-transmitting substrate (A)), and the light-transmitting substrate (A) and the hard coat layer (B) are formed. was manufactured. In the following description, the hard coat layer (B) formed in this example may be simply referred to as "HC layer". Further, hereinafter, the laminate of the light-transmitting substrate (A) and the hard coat layer (B) produced in this example may be referred to as "HC layer-attached PET film".

In addition, in this example, the average thickness dS of the light transmissive substrate (A) was measured with a linear gauge. Since the light-transmissive substrate (A) of this example has a uniform thickness, it can be estimated that the thickness at any point is equal to the average thickness dS. The average thickness dH of the hard coat layer (B) is obtained by measuring the average thickness of the laminate (HC layer-attached PET film) of the light-transmitting substrate (A) and the hard coat layer (B) with a linear gauge. , and the value obtained by subtracting dS from the value was defined as dH. For the average thickness dS+dH of the laminate of the light-transmitting substrate (A) and the hard coat layer (B), the thickness of any three points of the laminate was measured by imaging in a field of view of 1 μm square, and In the same manner, measurements were taken at 5 points in a 1 μm square field of view, and the average value of the thickness measurement results at a total of 15 points was taken as the average thickness dS+dH. The same applies to each example and comparative example described later.

Next, the HC layer surface of the HC layer-attached PET film was plasma-treated under a vacuum atmosphere of 1.0 Pa using a roll-to-roll type plasma treatment apparatus. In this plasma treatment, argon gas was used as an inert gas, and the discharge power was 780W.

Next, on the HC layer of the HC layer-attached PET film after the plasma treatment, an adhesion layer and an inorganic oxide base layer are formed in the order described above by a sputtering film formation method (sputter film formation step), thereby achieving the adhesion. An optical functional layer (C) composed of the layer and the inorganic oxide underlayer was formed (optical functional layer forming step). Specifically, first, an indium tin oxide (ITO) layer having a thickness of 2.0 nm as an adhesion layer is first formed on the HC layer of the HC layer-attached PET film by a roll-to-roll type sputtering deposition apparatus. formed. Next, using the same sputtering film forming apparatus, a SiO ₂ layer and a Nb ₂ O ₅ layer were formed on the ITO layer as inorganic oxide underlayers in the above order so that the total thickness was 0.23 μm. formed. The SiO ₂ layer was formed to have a thickness of 0.11 μm, and the Nb ₂ O ₅ layer was formed to have a thickness of 0.12 μm. As described above, an optical function layer (C) composed of the adhesion layer (ITO layer) and the inorganic oxide base layer (laminated body of the SiO ₂ layer and the Nb ₂ O ₅ layer) was formed. In forming the adhesion layer, an ITO target is used, argon gas is used as an inert gas, and 10 parts by volume of oxygen gas is used as a reactive gas with respect to 100 parts by volume of the argon gas. The ITO layer was formed by MFAC sputtering at 350 V and the pressure in the film formation chamber (film formation pressure) of 0.4 Pa. In the formation of the inorganic oxide underlayer, a Si target and an Nb target were used, 100 parts by volume of argon gas and 30 parts by volume of oxygen gas were used, the discharge voltage was 350 V, the film formation pressure was 0.3 Pa, and the MFAC The _SiO2 layer and the _Nb2O5 layer were formed by _sputtering .

In this example, the average thickness dI of the optical function layer (C) was measured by TEM (transmission electron microscope) observation of the cross section. Specifically, first, the surface of the optical functional layer (C) in the laminate of the light transmissive substrate (A), the hard coat layer (B) and the optical functional layer (C) is protected with an FIB resin, and then Cut in the depth direction. The cross section obtained by cutting is observed with a TEM (transmission electron microscope), and in the cross-sectional image, the optical functional layer (C) and the FIB resin protection from the interface between the hard coat layer (B) and the optical functional layer (C). The distance to the interface with the film was defined as the average thickness dI of the optical function layer (C). Since the optical function layer (C) in this example has a substantially uniform thickness, it can be estimated that the thickness at any point is equal to the average thickness dI. However, in this example, the thickness of the optical function layer (C) was measured at the same 15 points as the measurement points of the average thickness dS+dH of the laminate of the light-transmitting substrate (A) and the hard coat layer (B). , and the numerical value obtained by averaging the measurement results of the 15 points was defined as the average thickness dI of the optical function layer (C). The average thickness dI of the optical function layer (C) was measured in the same manner in each example and comparative example described later. The average thickness dI of the optical functional layer (C) can also be measured in the same manner for the hard coat film (on which the antifouling layer (D) is formed) as a finished product.

Further, an antifouling layer (D) was formed on the optical function layer (C) (antifouling layer forming step). Specifically, an antifouling layer (D) having a thickness of 10 nm was formed on the inorganic oxide underlayer by a vacuum deposition method using an alkoxysilane compound containing a perfluoropolyether group as a deposition source. The vapor deposition source is a solid content obtained by drying "KY1903-1" (perfluoropolyether group-containing alkoxysilane compound, solid content concentration: 20% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. The heating temperature of the vapor deposition source in the vacuum vapor deposition method was set to 260.degree.

In this example, the average thickness dF of the antifouling layer (D) was measured in the quantitative mode of a fluorescent X-ray spectrometer (manufactured by Rigaku Corporation, trade name ZXS Primus II). In this example, the thickness of the antifouling layer (D) was measured at the same 15 points as the measurement points of the average thickness dS+dH of the laminate of the light-transmitting substrate (A) and the hard coat layer (B). , and the average value of the 15 measurement results was taken as the average thickness dF of the antifouling layer (D). The same applies to each example and comparative example described later.

As described above, the hard coat layer (B), the optical function layer (C) and the antifouling layer (D) are laminated in the order described above on one surface of the light-transmitting substrate (A). A hard coat film of Example (Example 1) was produced.

[Examples 2 to 5 and Comparative Examples 1 to 4]
Change the average thickness of the hard coat layer (B), the optical function layer (C), and the antifouling layer (D) on one side of the light-transmitting substrate (A) as shown in Table 1 below. Hard coat films of Examples 2 to 5 and Comparative Examples 1 to 4 were produced in the same manner as in Example 1 except for the above. In Examples 2 to 5 and Comparative Examples 1 to 4, a PET film was used as the light transmissive substrate (A). In the optical function layer (C) of Comparative Example 1, the SiO ₂ layer was formed to have a thickness of 0.15 μm, and the Nb ₂ O ₅ layer was formed to have a thickness of 0.15 μm. In the optical function layer (C) of Comparative Examples 2 and 3, the SiO ₂ layer was formed to have a thickness of 0.20 μm, and the Nb ₂ O ₅ layer was formed to have a thickness of 0.20 μm. In the optical function layer (C) of Comparative Example 4, the SiO ₂ layer was formed to have a thickness of 0.05 μm, and the Nb ₂ O ₅ layer was formed to have a thickness of 0.05 μm.

Abrasion resistance tests and bending resistance tests were performed on the hard coat films of the examples and comparative examples produced as described above by the following measurement methods.

[Abrasion resistance test]
For each hard coat film of Examples and Comparative Examples, the degree of deterioration of the antifouling property of the surface of the antifouling layer (D) before and after rubbing the surface of the antifouling layer (D) with an eraser was measured. It was a test. Specifically, it is as follows. First, the surface of the antifouling layer (D) of the hard coat film was rubbed by bringing an eraser into contact with the eraser and reciprocating it. In this reciprocating motion, an eraser (Φ6 mm) manufactured by Minoan was used, the load of the eraser on the surface of the antifouling layer (D) was 1 kgw/6 mmΦ, and the moving distance of the eraser on the surface of the antifouling layer (D) (in the reciprocating motion The one-way distance) was set to 20 mm, the moving speed of the eraser was set to 40 rpm, and the number of reciprocating motions of the eraser to the antifouling layer (D) surface was set to 6000 times. On the other hand, on the surface of the antifouling layer (D), the water contact angle θ0 before rubbing and the water contact angle θ1 after rubbing of the portion rubbed with an eraser were measured by the following methods.

<Method for measuring water contact angle>
The water contact angle of the surface of the antifouling layer (C) opposite to the light-transmitting substrate (A) was measured for each of the hard coat films of Examples and Comparative Examples. First, about 1 μL of pure water was dropped on the surface of the antifouling layer to form water droplets. Next, the angle formed by water droplets on the surface of the antifouling layer (D) and the surface of the antifouling layer (D) was measured. A contact angle meter (trade name “DMo-501”, manufactured by Kyowa Interface Science Co., Ltd.) was used for the measurement.

<Evaluation of wear resistance>
The absolute value |θ0−θ1| of the difference between the water contact angle θ0 before rubbing and the water contact angle θ1 after rubbing was calculated on the surface of the antifouling layer (D). The smaller the value of |θ0−θ1|, the smaller the change in the surface condition before and after rubbing, and the better the abrasion resistance. As shown below, the abrasion resistance was evaluated in three grades of ◯Δ×.

○: |θ0-θ1|≦20°
△: 20°≦|θ0−θ1|≦30°
×: 30°≦|θ0−θ1|

[Preparation of adhesive composition A]
A pressure-sensitive adhesive composition A used in a bending resistance test described below was prepared by the following method.

(Preparation of acrylic oligomer)
60 parts by weight of dicyclopentanyl methacrylate (DCPMA) and 40 parts by weight of methyl methacrylate (MMA) as monomer components, 3.5 parts by weight of α-thioglycerol as a chain transfer agent, and 100 parts by weight of toluene as a polymerization solvent are mixed. and stirred at 70° C. for 1 hour under a nitrogen atmosphere. Next, 0.2 parts by weight of 2,2′-azobisisobutyronitrile (AIBN) was added as a thermal polymerization initiator, reacted at 70° C. for 2 hours, and then heated to 80° C. for 2 hours. reacted. After that, the reaction solution was heated to 130° C., and the toluene, chain transfer agent and unreacted monomer were removed by drying to obtain a solid acrylic oligomer. The acrylic oligomer had a weight average molecular weight of 5100 and a glass transition temperature (Tg) of 130°C.

(Polymerization of prepolymer)
As monomer components for forming the prepolymer, 43 parts by weight of lauryl acrylate (LA), 44 parts by weight of 2-ethylhexyl acrylate (2EHA), 6 parts by weight of 4-hydroxybutyl acrylate (4HBA), and N-vinyl-2-pyrrolidone (NVP ) and 0.015 parts by weight of "Omnirad 184" manufactured by IGM Resins as a photopolymerization initiator, and polymerized by irradiating ultraviolet rays to obtain a prepolymer composition (polymerization rate: about 10%). rice field.

(Preparation of adhesive composition)
To 100 parts by weight of the prepolymer composition, 0.07 parts by weight of 1,6-hexanediol diacrylate (HDDA), 3 parts by weight of the above oligomer, and a silane coupling agent (Shin-Etsu Chemical Co., Ltd. ("KBM403"): 0.3 parts by weight were added, and these were uniformly mixed to prepare a pressure-sensitive adhesive composition A.

[Bending resistance test]
As described below, using the hard coat films of Examples and Comparative Examples, simulated samples simulating an organic EL display device were manufactured, and a bending resistance test was performed using the simulated samples. First, as shown in FIG. 3A, the hard coat layer (B) 12, the optical functional layer (C) 13, and the antifouling layer (D) 14 in the light-transmitting substrate (A) 11 of the hard coat film are On the surface opposite to the laminated side, acrylic adhesive layer 21 (adhesive composition A, thickness 25 μm), polyimide film 22 (manufactured by KORON, thickness 50 μm), acrylic adhesive layer 23 (said Adhesive composition A, thickness 25 μm), PET film 24 (manufactured by Toray Industries, Inc., thickness 38 μm), and acrylic adhesive layer 25 (adhesive composition A, thickness 25 μm) are laminated in this order, A simulated sample 100 simulating an organic EL display device was manufactured. Next, as shown in FIG. 3B, a cylindrical core 200 made of stainless steel and having a diameter of 1 mm was brought into contact with the antifouling layer (D) 14 side of the simulated sample (D). After that, as shown in FIG. 3(c), the simulated sample 100 was folded toward the cylindrical core 200 to obtain a folded state. After that, the simulated sample 100 was opened and returned to the state shown in FIG. 3(b). This opening and closing (bending and opening) was repeated 150,000 times. This opening and closing was performed using a durability tester (model number "DMLHB-FS-C", manufactured by YUASA). Before and after opening and closing 150,000 times, the folded portion 101 (the contact portion between the simulated sample 100 and the cylindrical core 200) of the simulated sample 100 is irradiated with light from an LED light source (trade name LK-H766B manufactured by Twin Bird Co., Ltd.) and bent. The appearance of the portion 101 was visually inspected by reflection, and the bending resistance was evaluated in the following three grades of ◯Δ×.

◯: No change is observed in the appearance of the bent portion 101 before and after opening and closing.
Δ: The appearance of the bent portion 101 changes before and after opening and closing, but it is difficult to confirm the state of the change.
x: The appearance of the bent portion 101 significantly changed before and after opening and closing.

Table 1 below summarizes the test results of wear resistance and bending resistance tested as described above.

As shown in Table 1 above, dH×dI is in the range of 0.2 to 4 (satisfies the above formula (1)), and (dH+dI)/dS is in the range of 0.02 to 0.62. All of the hard coat films of Examples 1 to 5 (which satisfy the above formula (2)) had both surface abrasion resistance and bending resistance. On the other hand, none of the hard coat films of Comparative Examples 1 to 4 satisfy either of the above-mentioned formulas (1) and (2), and as a result, both surface wear resistance and bending resistance It was bad.

As described above, according to the present invention, it is possible to provide a hard coat film, an optical member, and an image display device that achieve both surface wear resistance and bending resistance. As described above, the hard coat film of the present invention can be used both as a clear film and as an antiglare film (antiglare hard coat film), and can be used in a wide variety of optical members and image display devices. Therefore, its industrial utility value is enormous.

This application claims priority based on Japanese Patent Application No. 2021-098260 filed on June 11, 2021, and the entire disclosure thereof is incorporated herein.

10, 10A Hard coat film 11 Light transmissive substrate (A)
12 Hard coat layer (B)
12a resin layer 12b particles 13 optical function layer (C)
14 antifouling layer (D)
21, 23, 25 Acrylic adhesive layer 22 Polyimide film 24 PET film 100 Simulated sample 101 Folding part 200 Cylindrical core

Claims

A hard coat layer (B), an optical functional layer (C) and an antifouling layer (D) are laminated in the order described above on at least one surface of the light transmissive substrate (A),
The antifouling layer (D) contains fluorine as an element,
A hard coat characterized in that the average thicknesses of the light-transmitting substrate (A), the hard coat layer (B), and the optical function layer (C) satisfy the relationships of the following formulas (1) and (2). the film.

0.2≦dH×dI≦4 (1)
0.02≦(dH+dI)/dS≦0.62 (2)

In the above formulas (1) and (2),
dS is the average thickness [μm] of the light transmissive substrate (A),
dH is the average thickness [μm] of the hard coat layer (B),
dI is the average thickness [μm] of the optical function layer (C).
The hard coat film according to claim 1, wherein the antifouling layer (D) has a surface roughness of 1 to 10 nm on the side opposite to the substrate (A).
The hard coat film according to claim 1 or 2, wherein the average thickness of the hard coat layer (B) is in the range of 2 to 12 µm.
The hard coat film according to any one of claims 1 to 3, wherein the light-transmitting substrate (A) has an average thickness of 100 µm or less.
The hard coat film according to any one of claims 1 to 4, wherein the antifouling layer (D) has an average thickness in the range of 1 to 30 nm.
The hard coat film according to any one of claims 1 to 5, wherein the hard coat layer (B) contains at least one selected from the group consisting of organic resin, silicon oxide, titanium oxide and zirconium oxide.
An optical member comprising the hard coat film according to any one of claims 1 to 6.
The optical member according to claim 7, which is a polarizing plate.
An image display device comprising the hard coat film according to any one of claims 1 to 6 or the optical member according to claim 7 or 8.
In the hard coat film, the hard coat layer (B), the optical function layer (C) and the antifouling layer (D) are arranged in the order described above on only one side of the light-transmitting substrate (A). laminated,
An adhesive layer is laminated on the other surface of the light-transmitting substrate (A),
10. The image display device according to claim 9, wherein the hard coat film is attached to a member containing glass or a plastic film through the adhesive layer.