Antireflective film and eye shield

Abstract

Provided is an antireflective film 1 comprising an optical functional layer 11 formed of resin, wherein the optical functional layer 11 has a fine uneven structure 12 including projections 13 or recesses 14 arranged at a pitch equal or inferior to the wavelength of visible light, the indentation elastic modulus of the optical functional layer 11 is 45 MPa or more, the water absorption rate of the optical functional layer 11 is 11 mass % or more, and the water contact angle of the surface of the optical functional layer 11 is 65° or more.

Description

Anti-reflection film and eye shield

[0001] The present invention relates to an anti-reflection film and an eye shield. This application claims the benefit of priority based on Japanese Patent Application No. 2024-166815 filed on September 25, 2024, the content of which is incorporated herein by reference.

[0002] Substrates constituting medical eye shields, industrial protective glasses, camera cover glasses, etc. are required to have an anti-fogging function and an anti-reflection function. As techniques for imparting an anti-fogging function, techniques for heating the substrate surface, techniques for laminating a hydrophilic film on the substrate surface, and techniques for laminating a water-absorbent film on the substrate surface have been proposed. The technique of heating the substrate surface exhibits an anti-fogging function by heating and evaporating fine water droplets adhering to the substrate surface. The technique of laminating a hydrophilic film on the substrate surface exhibits an anti-fogging function by spreading fine water droplets with the hydrophilic film to form a thin water film. The technique of laminating a water-absorbent film on the substrate surface exhibits an anti-fogging function by absorbing fine water droplets with the water-absorbent film.

[0003] Among the above techniques for imparting an anti-fogging function, the technique of heating the substrate surface has problems such as the apparatus becoming large-scale and not being applicable to eye shields, protective glasses, and camera cover glasses. Also, in the technique of laminating a hydrophilic film on the substrate surface, as the time of contact with high-humidity outside air increases, the thickness of the water film increases. Then, there is a problem that the water film becomes large water droplets and falls off from the hydrophilic film.

[0004] Therefore, as a technique for imparting an anti-fogging function to substrates constituting medical eye shields, industrial protective glasses, camera cover glasses, etc., the technique of laminating a water-absorbent film has been studied. As a technique for laminating a water-absorbent film, for example, Patent Document 1 discloses a technique of applying a film made of polyurethane having an oxyethylene group and having a water absorption rate of 15% by weight or more and 30% by weight or less to a glass substrate.

[0005] On the other hand, as a technology for providing anti-reflective properties, for example, Patent Document 2 discloses a technology for providing a film body having a fine uneven structure on its surface, in which multiple minute protrusions are arranged, to the surface of a substrate.

[0006] Patent No. 4992894, Patent No. 6391935

[0007] In order to achieve both anti-fogging and anti-reflective properties, it is conceivable to form the fine uneven structure described in Patent Document 2 using the material with a high water absorption rate described in Patent Document 1.

[0008] However, if a micro-textured structure is formed using a material with a high water absorption rate, the protrusions of the micro-textured structure will swell and soften and collapse when the structure absorbs water. This results in a physical deformation of the micro-textured structure, which impairs its anti-reflective function.

[0009] Therefore, the present invention has been made in view of the above problems, and the object of the present invention is to provide an anti-reflective film and an eye shield that can suppress deformation of the fine uneven structure due to water absorption and achieve both anti-fogging and anti-reflective functions.

[0010] To solve the above problems, according to one aspect of the present invention, an anti-reflective film is provided comprising an optical functional layer formed of resin, wherein the optical functional layer has a fine uneven structure including protrusions or recesses arranged at a pitch of less than or equal to the wavelength of visible light, the indentation modulus of the optical functional layer is 45 MPa or more, the water absorption rate of the optical functional layer is 11% by mass or more, and the water contact angle of the surface of the optical functional layer is 65° or more.

[0011] The resin forming the optical functional layer may consist of a cured product of an uncured resin composition, and the uncured resin composition may contain a silicone having an acrylic functional group.

[0012] The Martens hardness of the optical functional layer may be 3 MPa or higher.

[0013] The resin forming the optical functional layer may consist of a cured product of an uncured resin composition, and the uncured resin composition may contain an acrylate monomer having one or both of an ethylene oxide group and an acrylamide group.

[0014] The number of repeating units of the ethylene oxide group in the acrylate monomer having the ethylene oxide group may be 4 or more and 20 or less.

[0015] The content of the acrylate monomer having an ethylene oxide group in the uncured resin composition may be 90% by mass or less.

[0016] The content of acrylate monomers having acrylamide groups in the uncured resin composition may be 50% by mass or less.

[0017] The resin forming the optical functional layer may consist of a cured product of an uncured resin composition, and the uncured resin composition may contain a polyfunctional acrylate monomer.

[0018] The content of polyfunctional acrylate monomer in the uncured resin composition may be 10% by mass or more.

[0019] The material further comprises a substrate, and the optical functional layer may be provided on the substrate.

[0020] The optical functional layer may also have an anti-fogging function.

[0021] To solve the above problems, according to one aspect of the present invention, an eye shield is provided that includes the anti-reflective film described above.

[0022] As described above, according to the present invention, deformation of the fine uneven structure due to water absorption can be suppressed, thereby achieving both anti-fogging and anti-reflective functions.

[0023] Figure 1 is a schematic cross-sectional view showing an anti-reflective film according to one embodiment of the present invention. Figure 2 is a flowchart showing the procedure for calculating the water absorption rate according to the same embodiment. Figure 3 is a schematic perspective view showing a master disc according to the same embodiment. Figure 4 is a schematic diagram showing the configuration of a transfer apparatus for manufacturing a transfer product using the master disc according to the same embodiment.

[0024] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. In this specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant descriptions will be omitted.

[0025] [1. Structure of the Anti-Reflective Film] First, the structure of the anti-reflective film 1 according to one embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a schematic cross-sectional view showing the anti-reflective film 1 according to this embodiment.

[0026] As shown in Figure 1, the anti-reflective film 1 comprises, for example, a substrate 10 and an optical functional layer 11. The optical functional layer 11 is provided on the substrate 10. The optical functional layer 11 has a fine uneven structure 12 on its surface. The fine uneven structure 12 has a plurality of fine protrusions 13 or recesses 14 arranged at a pitch of visible light wavelength (for example, 380 nm or more and 830 nm or less).

[0027] The base material 10 constitutes the base material of the anti-reflective film 1. The base material 10 is, for example, a flexible film-like base material. Therefore, the entire anti-reflective film 1 is also flexible. The base material 10 may be, for example, a flat film as shown in Figure 1, or a curved or corrugated film. The planar shape (XY plane), size, and thickness (Z direction) of the base material 10 are not particularly limited, but are preferably adjusted as appropriate according to the application of the anti-reflective film 1.

[0028] The base material 10 is formed of, for example, a transparent material, preferably a transparent organic material. The base material 10 is preferably formed of a resin material with excellent light transmittance, and in particular, a resin material with excellent visible light transmittance. "Transparent" means that the transmittance of light having wavelengths belonging to the visible light range (for example, 380 nm or more and 830 nm or less) is high, and for example, the visible light transmittance may be 70% or more, preferably 90% or more. The visible light transmittance can be measured by a spectrophotometer. The measurement results can be used to calculate the transmittance from wavelengths of 380 nm to 900 nm according to JIS R 3106:1998, and the visible light transmittance can be calculated as the average of the transmittances in these wavelength ranges.

[0029] Examples of organic resins for the base material 10 include polyethylene terephthalate (PET), polycarbonate, polymethyl methacrylate, triacetylcellulose (TAC), cyclic olefin polymer (COP), or cyclic olefin copolymer (COC).

[0030] Furthermore, the substrate 10 may be formed from an inorganic material with excellent visible light transmittance. For example, the substrate 10 may be formed from a transparent glass material such as quartz glass, soda-lime glass, or lead glass.

[0031] The optical functional layer 11 is a layer laminated on the substrate 10. The optical functional layer 11 is made of resin. The material of the optical functional layer 11 will be described in detail later. A micro-recessed structure 12 having fine irregularities (protrusions 13 and recesses 14) is formed on the surface of the optical functional layer 11.

[0032] The micro-textured structure 12 may be, for example, a structure having nano-order fine irregularities formed on the surface of the substrate 10 (a so-called moth-eye structure). The pitch (average period) of the irregularities in the micro-textured structure 12 is less than or equal to the wavelength of visible light (for example, 380 nm or more and 830 nm or less). The micro-textured structure 12 has the function of preventing light reflection on the surface of the anti-reflective film 1 (anti-reflective function). By providing such a micro-textured structure 12, the anti-reflective film 1 will have an anti-reflective function.

[0033] The micro-textured surface 12 is provided on at least one surface of the substrate 10. In the example shown in Figure 1, the micro-textured surface 12 is provided only on one surface of the substrate 10 (i.e., surface 10A). However, the example is not limited to this, and for example, the micro-textured surface 12 may be provided on both surfaces of the substrate 10 (i.e., surface 10A and back surface 10B).

[0034] The fine uneven structure 12 has a plurality of protrusions 13 and a plurality of recesses 14. The protrusions 13 are projection-like structures that protrude perpendicularly from the surface of the substrate 10. The recesses 14 are recessed portions between adjacent protrusions 13. The size and arrangement pitch of the protrusions 13 are, for example, tens of nanometers or more and hundreds of nanometers or less (nano-order), and are extremely fine.

[0035] In order to exhibit the anti-reflective function of visible light, etc., by the micro-textured structure 12, the protrusions (protrusions 13 and recesses 14) of the micro-textured structure 12 are arranged on the surface of the substrate 10 at a pitch less than or equal to the wavelength of visible light. In other words, the pitch of the multiple protrusions 13 constituting the micro-textured structure 12 is less than or equal to the wavelength of visible light. For example, if the wavelength range of visible light (i.e., the visible light range) is, for example, 380 nm or more and 830 nm or less, the pitch is 380 nm or less.

[0036] In the micro-textured structure 12, the average distance between adjacent protrusions 13, 13 is preferably 5 nm or more and 1000 nm or less, more preferably 10 nm or more and 500 nm, and even more preferably 50 nm or more and 300 nm. Also, in the micro-textured structure 12, the average distance between adjacent recesses 14, 14 is preferably 5 nm or more and 1000 nm or less, more preferably 10 nm or more and 500 nm, and even more preferably 50 nm or more and 300 nm. This improves the anti-reflective function of the optical functional layer 11.

[0037] Furthermore, in the fine uneven structure 12, the average height of the protrusions 13 is preferably 1 nm or more and 1000 nm or less, more preferably 5 nm or more and 500 nm or less, even more preferably 10 nm or more and 300 nm or less, and particularly preferably 50 nm or more and 300 nm or less. This improves the transferability and peelability of the master disc in the transfer process described later, and improves the production efficiency of the optical functional layer 11. It also improves the anti-reflective function of the optical functional layer 11.

[0038] By providing a micro-rough structure 12 consisting of multiple protrusions 13 arranged at the minute pitch described above on the surface of the optical functional layer 11, a moth-eye structure with excellent visible light anti-reflection properties can be formed on the surface of the anti-reflective film 1. This creates an effective refractive index gradient at the interface between the optical functional layer 11 and the outside air. Therefore, light (visible light, etc.) incident on the surface of the anti-reflective film 1 and passing through the micro-rough structure 12 is gently refracted, and surface reflection is suppressed.

[0039] In addition, it is preferable that the fine concavo-convex structure 12 according to the present embodiment has a hexagonal lattice arrangement in which a plurality of convex portions 13 are arranged at the vertices and the center of a hexagon on the surface of the base material 10 (on the XY plane). Thereby, a large number of convex portions 13 are arranged so as to be most densely packed on the surface of the base material 10 (on the XY plane), and the antireflection function as a moth-eye structure can be improved. However, the plurality of convex portions 13 of the fine concavo-convex structure 12 are not limited to the above hexagonal lattice example, and may be regularly arranged in other modes such as a square lattice, a rectangular lattice, a triangular lattice, etc. Alternatively, the plurality of convex portions 13 may be irregularly arranged on the surface of the base material 10. For example, the plurality of convex portions 13 may be irregularly arranged at positions randomly shifted within a range of a predetermined variation width from the positions of the above various lattice arrangements while using the above various lattice arrangements as a reference.

[0040] As shown in FIG. 1, the fine concavo-convex structure 12 may be formed only on one surface (surface 10A) of the base material 10, and not formed on the other surface (back surface 10B). Thereby, the reflection of incident light on the surface 10A of the base material 10 can be suppressed, and the reflection of incident light on one surface of the antireflection film 1 can be suppressed.

[0041] Although not shown, if the fine concavo-convex structure 12 is formed on both surfaces (surface 10A and back surface 10B) of the base material 10, the reflection of incident light and outgoing light on the surface 10A and back surface 10B of the base material 10 can be suppressed. Although not shown, a fine concavo-convex structure 12 may be provided on one surface of the base material 10, and an antireflection film having a multilayer structure may be provided on the other surface.

[0042] In addition, the antireflection film 1 according to the present embodiment may not include the base material 10. That is, the antireflection film 1 may be composed only of the optical functional layer 11.

[0043] In addition, it is preferable that the optical functional layer 11 according to the present embodiment has an antifogging function in addition to the above antireflection function.

[0044] [2. Characteristics of the optical functional layer] Next, the characteristics of the optical functional layer 11 according to this embodiment will be described. The optical functional layer 11 according to this embodiment has the following characteristics (A), (B), and (C). In addition, the optical functional layer 11 according to this embodiment preferably has the following characteristics (D) and (E) in addition to characteristics (A), (B), and (C).

[0045] (A) Indentation elastic modulus The indentation elastic modulus according to this embodiment is calculated by the Oliver & Pharr method based on a curve fitted in the range of 40% to 98% with respect to the maximum load among the unloading curves obtained by pressing a Vickers indenter against the surface of the optical functional layer 11 using an indentation tester. In this embodiment, the indentation elastic modulus is calculated based on the unloading curve obtained under the conditions of a load of 0.5 mN / 10 s, holding for 10 s, and unloading at 0.5 mN / 10 s. The indentation tester is, for example, a nanoindentation tester manufactured by Anton Paar, model name "Hit 300".

[0046] The indentation elastic modulus of the optical functional layer 11 according to this embodiment obtained by the above calculation method is 45 MPa or more, preferably 100 MPa or more, more preferably 150 MPa or more, and even more preferably 200 MPa or more. If the indentation elastic modulus of the optical functional layer 11 is less than 45 MPa, when the optical functional layer 11 absorbs water, the convex portions 13 of the fine concavo-convex structure 12 swell, soften, and collapse. Then, the fine concavo-convex structure 12 is physically deformed, and the antireflection function by the fine concavo-convex structure 12 is impaired. In addition, since the fine concavo-convex structure 12 is deformed, the transparency of the optical functional layer 11 is lowered. Since the indentation elastic modulus of the optical functional layer 11 according to this embodiment is 45 MPa or more, deformation of the fine concavo-convex structure 12 due to water absorption can be suppressed. Therefore, it is possible to suppress a decrease in the antireflection function of the optical functional layer 11 and also suppress a decrease in transparency.

[0047] Furthermore, the indentation modulus of the optical functional layer 11 according to this embodiment, obtained by the calculation method, is, for example, 5000 MPa or less, preferably 4000 MPa or less, more preferably 3500 MPa or less, and even more preferably 1000 MPa or less. If the indentation modulus of the optical functional layer 11 exceeds 5000 MPa, cracks will occur in the optical functional layer 11 after transfer. Since the indentation modulus of the optical functional layer 11 according to this embodiment is 5000 MPa or less, it is possible to avoid the situation in which cracks occur in the optical functional layer 11 after transfer.

[0048] Furthermore, the indentation modulus of the optical functional layer 11 according to this embodiment may be the indentation modulus measured by the measurement method specified in ISO 14577. In other words, the indentation modulus of the optical functional layer 11 according to this embodiment obtained by the measurement method specified in ISO 14577 may be 45 MPa or more and 5000 MPa or less.

[0049] (B) Water Absorption Rate The water absorption rate according to this embodiment is calculated by the procedure shown in Figure 2. Figure 2 is a flowchart showing the procedure for calculating the water absorption rate according to this embodiment. As shown in Figure 2, first, in step S10, the optical functional layer 11 is exposed to an environment of 23°C and 50% RH for 24 hours or more. Next, in step S12, the mass M1 of the optical functional layer 11 is measured. Subsequently, in step S14, the optical functional layer 11 is immersed in distilled water at 23°C for 24 hours or more. Then, in step S16, the optical functional layer 11 is removed from the distilled water and any moisture adhering to the surface is removed. Subsequently, in step S18, the mass M2 of the optical functional layer 11 is measured. Finally, in step S20, the water absorption rate of the optical functional layer 11 is calculated using the following formula (A). Water absorption rate [mass %] = (mass M2 - mass M1) / mass M1 × 100 …Formula (A)

[0050] The water absorption rate of the optical functional layer 11 according to this embodiment, obtained by the calculation method, is 11% by mass or more, preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. If the water absorption rate of the optical functional layer 11 is less than 11% by mass, the anti-fogging function of the optical functional layer 11 will be reduced. Since the water absorption rate of the optical functional layer 11 according to this embodiment is 11% by mass or more, it is possible to exhibit the anti-fogging function.

[0051] Furthermore, the water absorption rate of the optical functional layer 11 according to this embodiment, obtained by the calculation method, is, for example, 50% by mass or less, preferably 40% by mass or less, and more preferably 30% by mass or less. If the water absorption rate of the optical functional layer 11 exceeds 50% by mass, the optical functional layer 11 itself will whiten (become cloudy) when it absorbs water, and the transparency of the optical functional layer 11 will decrease. Since the water absorption rate of the optical functional layer 11 according to this embodiment is 50% by mass or less, whitening of the optical functional layer 11 itself when it absorbs water can be prevented. Therefore, a decrease in the transparency of the optical functional layer 11 can be prevented.

[0052] (C) Water Contact Angle The water contact angle according to this embodiment is measured using a contact angle meter by the droplet method under the following conditions: Amount of water dropped: 1.0 μL Measurement temperature: 25°C The water contact angle of the optical functional layer 11 is calculated by the θ / 2 method based on the measurement value after 10 seconds have elapsed since dropping water onto the surface of the optical functional layer 11.

[0053] The contact angle meter in question is, for example, the "Contact Angle Meter DMe-700" manufactured by Kyowa Interface Chemical Co., Ltd.

[0054] The water contact angle of the surface of the optical functional layer 11 according to this embodiment, obtained by the calculation method, is 65° or more, preferably 80° or more, more preferably 100° or more, and even more preferably 120° or more. When the optical functional layer 11 absorbs water, the protrusions 13 of the micro-textured structure 12 may swell and soften and collapse. If the water contact angle of the surface of the optical functional layer 11 is less than 65°, the collapsed protrusions 13 will stick together when they come into contact with each other. In this case, even if the water is removed from the optical functional layer 11 and the swelling is relieved, the physical deformation of the micro-textured structure 12 is maintained, and the anti-reflective function of the micro-textured structure 12 is impaired. In addition, because the micro-textured structure 12 is deformed, the transparency of the optical functional layer 11 decreases. In this embodiment, the water contact angle of the surface of the optical functional layer 11 is 65° or more. Therefore, even if the protrusions 13 of the fine uneven structure 12 swell and soften due to water absorption by the optical functional layer 11, causing them to come into contact with each other, the protrusions 13 can be prevented from sticking together. As a result, when the water is removed and the swelling subsides, the optical functional layer 11 in this embodiment can restore the fine uneven structure 12 to its original shape. Consequently, a decrease in the anti-reflective function of the optical functional layer 11 can be suppressed, and a decrease in transparency can also be suppressed.

[0055] The water contact angle of the surface of the optical functional layer 11 according to this embodiment, obtained by the calculation method, is preferably 150° or less. This makes it possible to manufacture the optical functional layer 11 according to this embodiment at low cost and efficiently.

[0056] In this embodiment, the water contact angle of the surface of the optical functional layer 11 may be the water contact angle measured by the measurement method specified in JIS R 3257 (1999). In other words, the water contact angle of the surface of the optical functional layer 11 obtained by the measurement method specified in JIS R 3257 (1999) may be 65° or more and 150° or less.

[0057] (D) Martens hardness The Martens hardness according to this embodiment is calculated by dividing the test load applied when a Vickers indenter is pressed against the surface of the optical functional layer 11 using an indentation tester by the surface area into which the Vickers indenter penetrates the optical functional layer 11. The test load is, for example, the maximum test load. In this embodiment, the Martens hardness is calculated based on the conditions of a load of 0.5 mN / 10 seconds, a holding time of 10 seconds, and an unloading time of 0.5 mN / 10 seconds. The indentation tester is, for example, a nanoindentation tester manufactured by Anton Paar, product name "Hit 300".

[0058] The Martens hardness of the optical functional layer 11 according to this embodiment, obtained by the calculation method, is, for example, 3 MPa or more, preferably 5 MPa or more, more preferably 10 MPa or more, and even more preferably 15 MPa or more. If the Martens hardness of the optical functional layer 11 is less than 3 MPa, when the optical functional layer 11 absorbs water, the protrusions 13 of the fine uneven structure 12 swell and soften and collapse. As a result, the fine uneven structure 12 is physically deformed, and the anti-reflective function of the fine uneven structure 12 is impaired. In addition, because the fine uneven structure 12 is deformed, the transparency of the optical functional layer 11 decreases. Since the Martens hardness of the optical functional layer 11 according to this embodiment is 3 MPa or more, deformation of the fine uneven structure 12 due to water absorption can be suppressed. Therefore, the decrease in the anti-reflective function of the optical functional layer 11 can be suppressed, and the decrease in transparency can also be suppressed.

[0059] Furthermore, the Martens hardness of the optical functional layer 11 according to this embodiment, obtained by the calculation method, is, for example, 200 MPa or less, preferably 170 MPa or less, more preferably 150 MPa or less, even more preferably 140 MPa or less, and particularly preferably 100 MPa or less. If the Martens hardness of the optical functional layer 11 exceeds 200 MPa, cracks will occur in the optical functional layer 11 after transfer. Since the Martens hardness of the optical functional layer 11 according to this embodiment is 200 MPa or less, it is possible to avoid the situation in which cracks occur in the optical functional layer 11 after transfer.

[0060] In this embodiment, the Martens hardness of the optical functional layer 11 may be the Martens hardness measured by the measurement method specified in ISO 14577. In other words, the Martens hardness of the optical functional layer 11 obtained by the measurement method specified in ISO 14577 may be 3 MPa or more and 200 MPa or less.

[0061] (E) Thickness The thickness (Z direction) of the optical functional layer 11 according to this embodiment is, for example, 2 μm or more, preferably 4 μm or more, and more preferably 8 μm or more. If the thickness (layer thickness) of the optical functional layer 11 is less than 2 μm, a defect will occur if foreign matter is mixed in during the transfer process. Also, if the thickness of the optical functional layer 11 is less than 2 μm, the anti-fogging function of the optical functional layer 11 will be reduced. Since the thickness of the optical functional layer 11 according to this embodiment is 2 μm or more, the occurrence of defects can be prevented even if foreign matter is mixed in during the transfer process. Also, since the thickness of the optical functional layer 11 according to this embodiment is 2 μm or more, the reduction in the anti-fogging function can be suppressed.

[0062] Furthermore, the thickness of the optical functional layer 11 according to this embodiment, obtained by the calculation method, is, for example, 20 μm or less, preferably 15 μm or less, and more preferably 10 μm or less. If the thickness of the optical functional layer 11 exceeds 20 μm, the curl of the optical functional layer 11 may increase or the optical functional layer 11 may crack due to shrinkage of the optical functional layer 11 during the curing process described later. Since the thickness of the optical functional layer 11 according to this embodiment is less than 20 μm, the curl of the optical functional layer 11 due to shrinkage can be reduced, and the situation in which the optical functional layer 11 cracks can be avoided.

[0063] [3. Composition of the uncured resin composition forming the optical functional layer] Next, the composition of the resin forming the optical functional layer 11 according to this embodiment will be described. Preferably, the resin forming the optical functional layer 11 according to this embodiment consists of a cured product of an uncured resin composition.

[0064] The uncured resin composition preferably contains silicone having acrylic functional groups. This allows the silicone having acrylic functional groups to segregate on the surface of the fine uneven structure 12 of the optical functional layer 11 during the transfer process. As a result, it is possible to improve the water contact angle of the surface of the fine uneven structure 12 of the optical functional layer 11. Furthermore, it is possible to improve the release properties of the optical functional layer 11 from the master disc during the transfer process.

[0065] Furthermore, the uncured resin composition may contain an acrylate monomer having one or both of ethylene oxide groups and acrylamide groups. This can improve the water absorption rate of the cured product of the uncured resin composition. In other words, by including an acrylate monomer having one or both of ethylene oxide groups and acrylamide groups in the uncured resin composition, the water absorption rate of the optical functional layer 11 can be improved.

[0066] Furthermore, the uncured resin composition may contain a polyfunctional acrylate monomer. This can improve the indentation modulus of the cured product of the uncured resin composition. In other words, by including a polyfunctional acrylate monomer in the uncured resin composition, the indentation modulus of the optical functional layer 11 can be improved.

[0067] [3.1. Acrylate Monomers Having an Ethylene Oxide Group] The acrylate monomer having an ethylene oxide group is one or more selected from the group consisting of, for example, polyethylene glycol monoacrylate shown in formula (1) below, polyethylene glycol diacrylate shown in formula (2) below, trimethylolpropane EO-modified triacrylate shown in formula (3) below, pentaerythritol EO-modified tetraacrylate shown in formula (4) below, dipentaerythritol EO-modified polyacrylate shown in formula (5) below, and glycerin EO-modified triacrylate shown in formula (6) below, and preferably trimethylolpropane EO-modified triacrylate shown in formula (3) below. "EO" represents ethylene oxide. The acrylate monomer shown in formula (1) below can be obtained, for example, from NOF Corporation. The acrylate monomers shown in formulas (2) to (6) below can be obtained, for example, from Shin Nakamura Chemical Industry Co., Ltd.

[0068] /

[0069] /

[0070] In formulas (3), (4), and (6) above, R represents an ethylene oxide group. In formula (5) above, X represents an ethylene oxide group.

[0071] The repeating units of the ethylene oxide group in the acrylate monomer having an ethylene oxide group may be 4 or more and 20 or less. For example, one or more selected from the group consisting of a, b, c, d, e, f, n, m, l, and k in formulas (1) to (6) above may be 4 or more and 20 or less. If the repeating units of the ethylene oxide group in the acrylate monomer are less than 4, the water absorption rate of the optical functional layer 11 will decrease. On the other hand, if the repeating units of the ethylene oxide group in the acrylate monomer exceed 20, the indentation modulus of the optical functional layer 11 will decrease. By setting the repeating units of the ethylene oxide group in the acrylate monomer having an ethylene oxide group to 4 or more and 20 or less, it is possible to achieve both a high water absorption rate and a high indentation modulus in the optical functional layer 11.

[0072] Furthermore, the content of acrylate monomers having ethylene oxide groups in the uncured resin composition is, for example, 90% by mass or less, preferably 70% by mass or less, and more preferably 60% by mass or less. If the content of acrylate monomers having ethylene oxide groups in the uncured resin composition exceeds 90% by mass, the optical functional layer 11 itself will whiten when it absorbs water, and the transparency of the optical functional layer 11 will decrease. Therefore, by keeping the content of acrylate monomers having ethylene oxide groups in the uncured resin composition at 90% by mass or less, whitening of the optical functional layer 11 itself when it absorbs water can be prevented. Thus, a decrease in the transparency of the optical functional layer 11 can be prevented.

[0073] Furthermore, the content of acrylate monomers having ethylene oxide groups in the uncured resin composition is, for example, greater than 0% by mass, preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 40% by mass or more, and particularly preferably 50% by mass or more. The higher the content of acrylate monomers having ethylene oxide groups in the uncured resin composition, the greater the water absorption rate of the optical functional layer 11, but the lower the indentation modulus. Therefore, by having a content of acrylate monomers having ethylene oxide groups in the uncured resin composition greater than 0% by mass, it is possible to achieve both a high water absorption rate and a high indentation modulus in the optical functional layer 11.

[0074] [3.2. Acrylate Monomers Having an Acrylamide Group] An acrylate monomer having an acrylamide group is, for example, a monofunctional acrylamide monomer. An acrylate monomer having an acrylamide group is, for example, one or more selected from the group consisting of N,N-dimethylacrylamide shown in formula (7) below, N,N-diethylacrylamide shown in formula (8) below, acryloylmorpholine shown in formula (9) below, and N-(2-hydroxyethyl)acrylamide shown in formula (10) below, and preferably N,N-dimethylacrylamide shown in formula (7) below. Acrylate monomers shown in formulas (7) to (10) below can be obtained, for example, from KJ Chemicals Co., Ltd.

[0075] /

[0076] The content of acrylate monomers having acrylamide groups in the uncured resin composition is, for example, 50% by mass or less, preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. If the content of acrylate monomers having acrylamide groups in the uncured resin composition exceeds 50% by mass, the crosslinking density of the cured product (resin after curing) decreases, and the scratch resistance and abrasion resistance of the fine uneven structure 12 of the optical functional layer 11 decreases. For this reason, by keeping the content of acrylate monomers having acrylamide groups in the uncured resin composition at 50% by mass or less, the scratch resistance and abrasion resistance of the optical functional layer 11 can be improved.

[0077] Furthermore, the content of acrylate monomers having acrylamide groups in the uncured resin composition is, for example, greater than 0% by mass, preferably 5% by mass or more, and more preferably 10% by mass or more. The higher the content of acrylate monomers having acrylamide groups in the uncured resin composition, the greater the water absorption rate of the optical functional layer 11. Therefore, by increasing the content of acrylate monomers having acrylamide groups in the uncured resin composition above 0% by mass, the water absorption rate of the optical functional layer 11 can be increased.

[0078] [3.3. Polyfunctional Acrylate Monomers] Polyfunctional acrylate monomers are, for example, one or more selected from the group consisting of difunctional acrylate monomers, trifunctional acrylate monomers, tetrafunctional acrylate monomers, pentafunctional acrylate monomers, and hexafunctional acrylate monomers. The polyfunctional acrylate monomer is, for example, one or more selected from the group consisting of trimethylolpropane triacrylate shown in formula (11) below, pentaerythritol triacrylate shown in formula (12) below, pentaerythritol tetraacrylate shown in formula (13) below, dipentaerythritol hexaacrylate shown in formula (14) below, tricyclodecanedimethanol diacrylate shown in formula (15) below, and hexanediol diacrylate shown in formula (16) below. Preferably, it is one or more selected from the group consisting of pentaerythritol triacrylate shown in formula (12) below, pentaerythritol tetraacrylate shown in formula (13) below, and tricyclodecanedimethanol diacrylate shown in formula (15) below. The acrylate monomers shown in formulas (11) to (16) below can be obtained, for example, from Shin Nakamura Chemical Industry Co., Ltd.

[0079] /

[0080] Furthermore, the content of polyfunctional acrylate monomer in the uncured resin composition is, for example, 10% by mass or more, preferably 15% by mass or more, and more preferably 20% by mass or more. If the content of polyfunctional acrylate monomer in the uncured resin composition is less than 10% by mass, the indentation modulus of the optical functional layer 11 will decrease. Therefore, by having a content of polyfunctional acrylate monomer in the uncured resin composition of 10% by mass or more, the indentation modulus of the optical functional layer 11 can be improved.

[0081] Furthermore, the content of polyfunctional acrylate monomers in the uncured resin composition is, for example, 60% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. If the content of polyfunctional acrylate monomers in the uncured resin composition exceeds 60% by mass, the water absorption rate of the optical functional layer 11 will decrease. Therefore, by keeping the content of polyfunctional acrylate monomers in the uncured resin composition at 60% by mass or less, a decrease in the water absorption rate of the optical functional layer 11 can be prevented.

[0082] [3.4. Silicones having acrylic functional groups] Silicones having acrylic functional groups include, for example, one or both of the following: acrylic group-containing polyester-modified polydimethylsiloxane and acrylic group-containing polyether-modified polydimethylsiloxane.

[0083] Furthermore, the content of silicone having acrylic functional groups in the uncured resin composition is, for example, 0.1% by mass or more, preferably 1% by mass or more, and more preferably 3% by mass or more, when the total of acrylate monomers having one or both of ethylene oxide groups and acrylamide groups, and polyfunctional acrylate monomers is taken as 100% by mass. If the content of silicone having acrylic functional groups in the uncured resin composition is less than 0.1% by mass, the release properties of the optical functional layer 11 from the master disc in the transfer process will decrease. Therefore, by having a content of silicone having acrylic functional groups in the uncured resin composition of 0.1% by mass or more, the release properties of the optical functional layer 11 from the master disc in the transfer process can be improved. Also, if the content of silicone having acrylic functional groups in the uncured resin composition is less than 0.1% by mass, the silicone having acrylic functional groups will hardly segregate on the surface of the fine uneven structure 12 of the optical functional layer 11 in the transfer process. Therefore, by having a content of acrylic functional group-containing silicone of 0.1% by mass or more in the uncured resin composition, the acrylic functional group-containing silicone can be efficiently segregated onto the surface of the fine uneven structure 12 of the optical functional layer 11 during the transfer process. This makes it possible to improve the water contact angle of the surface of the fine uneven structure 12 of the optical functional layer 11.

[0084] Furthermore, the content of silicone having acrylic functional groups in the uncured resin composition is, for example, 10% by mass or less, preferably 7% by mass or less, and more preferably 5% by mass or less, when the total of acrylate monomers having one or both of ethylene oxide groups and acrylamide groups, and polyfunctional acrylate monomers is taken as 100% by mass. If the content of silicone having acrylic functional groups in the uncured resin composition exceeds 10% by mass, the water absorption rate of the optical functional layer 11 will decrease. Therefore, by keeping the content of silicone having acrylic functional groups in the uncured resin composition at 10% by mass or less, a decrease in the water absorption rate of the optical functional layer 11 can be prevented.

[0085] [3.5. Other Components] The uncured resin composition may further contain a photopolymerization initiator. The photopolymerization initiator is, for example, an α-hydroxyacetophenone-based photopolymerization initiator. As a photopolymerization initiator, for example, the product name "Omnirad 127" manufactured by IGM Resins B.V. can be used.

[0086] Furthermore, the uncured resin composition may contain other components (additives) to improve adhesion to the substrate 10, adjust the viscosity of the uncured resin composition, and so on. Examples of other components include antioxidants, phosphors, plasticizers, ultraviolet absorbers, defoamers, thixotropes, polymerization inhibitors, release agents, and metal oxide particles.

[0087] [4. Master Plate Configuration] Next, with reference to Figure 3, the master plate 100 used to form the fine uneven structure 12 of the anti-reflective film 1 according to this embodiment will be described. Figure 3 is a schematic perspective view showing the master plate 100 according to this embodiment.

[0088] The master disc 100 is a mold for transferring a fine uneven structure 120 onto the surface of a transfer material (for example, the anti-reflective film 1 according to this embodiment) by a roll-to-roll imprinting method. From the viewpoint of efficiently producing the transfer material, the master disc 100 is preferably a roll-shaped master disc having a cylindrical or columnar shape, but it may also be a flat master disc. If the master disc 100 is a roll-shaped master disc, the fine uneven structure 120 of the master disc 100 can be seamlessly transferred to the substrate of the transfer material by the roll-to-roll method. This makes it possible to manufacture transfer materials with the fine uneven structure 120 of the master disc 100 transferred onto them with high production efficiency.

[0089] As shown in Figure 3, the master disc 100 comprises a roll-shaped base material 110 and a fine uneven structure 120 formed on the outer surface of the base material 110.

[0090] The base material 110 is, for example, a roll-shaped member that serves as the base material for a roll master. The shape of the base material 110 may be a hollow cylindrical shape as shown in Figure 3, or it may be a solid cylindrical shape without any internal cavities. Furthermore, the material of the base material 110 is not particularly limited and may be quartz glass such as fused silica glass or synthetic silica glass (SiO ２ ), or metals such as stainless steel can be used. The size of the base material 110 is not particularly limited, but for example, the length of the base material 110 in the direction of the central axis 110a (hereinafter sometimes referred to as the axial direction) may be 100 mm or more, and the outer diameter of the base material 110 may be 50 mm or more and 300 mm or less. In addition, the radial thickness of the cylindrical base material 110 may be 2 mm or more and 50 mm or less.

[0091] The micro-textured structure 120 is a micro-textured pattern formed on the outer surface of the master disc 100. The micro-textured structure 120 comprises a plurality of fine recesses 122 arranged at a predetermined pitch, and a plurality of fine protrusions 123 provided between two adjacent recesses 122, 122. The micro-textured structure 120 of the master disc 100 has an inverted shape of the micro-textured structure of the transfer material (for example, the micro-textured structure 12 of the anti-reflective film 1). For example, the shape of the recesses 122 of the micro-textured structure 120 of the master disc 100 is an inverted shape of the protrusions 13 (see Figure 1) of the micro-textured structure 12 of the anti-reflective film 1. Similarly, the shape of the protrusions 123 of the micro-textured structure 120 of the master disc 100 is an inverted shape of the recesses 14 (see Figure 1) of the micro-textured structure 12 of the anti-reflective film 1. Furthermore, the pitch of the recesses 122 of the micro-uneven structure 120 of the master disc 100 (circumferential dot pitch) is the same as the pitch of the protrusions 13 of the micro-uneven structure 12 of the anti-reflective film 1.

[0092] Furthermore, in this embodiment, it is preferable that a release layer containing a fluoropolymer is formed on the surface of the fine uneven structure 120 of the master disc 100. For example, the release layer may be formed by applying a fluoropolymer coating agent to the surface of the fine uneven structure 120 of the master disc 100 and then subjecting it to a heat treatment. Examples of fluoropolymer coating agents that can be used include "Novec® 1720" manufactured by 3M Japan Ltd., "Optool DSX-F" manufactured by Daikin Industries, Ltd., "Fluorosurf® FG-5080" or "Fluorosurf® NL-1" manufactured by Fluorotechnology Ltd. The heat treatment is, for example, a process of heating at 100°C for 30 minutes.

[0093] By forming a release layer containing a fluoropolymer on the surface of the fine uneven structure 120 of the master disc 100, the surface energy of the fine uneven structure 120 of the master disc 100 can be lowered. This allows for suitable segregation of silicone having acrylic functional groups on the surface of the fine uneven structure 12 of the optical functional layer 11 during the transfer process.

[0094] A master disc 100 with such a configuration is provided in a roll-to-roll imprint transfer apparatus, for example, the transfer apparatus 300 shown in Figure 4. The master disc 100 can be used to manufacture a transfer product (for example, an anti-reflective film 1 according to this embodiment) on which the fine uneven structure 120 formed on the outer surface of the master disc 100 has been transferred. For example, the fine uneven structure 120 on the outer surface of the master disc 100 can be continuously transferred to the resin layer on the surface of the anti-reflective film 1, thereby forming the fine uneven structure 12 on the surface of the anti-reflective film 1 with high precision and efficiency.

[0095] [5. Method for Manufacturing Transfer Materials] Next, with reference to Figure 4, a method for efficiently manufacturing transfer materials such as the anti-reflective film 1 according to this embodiment using a transfer apparatus 300 equipped with a master disc 100 will be described. Figure 4 is a schematic diagram showing the configuration of a transfer apparatus 300 for manufacturing transfer materials using the master disc 100 according to this embodiment.

[0096] As shown in Figure 4, the transfer device 300 is a roll-to-roll type imprint transfer device. The transfer device 300 transfers the fine uneven structure 120 of the master disc 100 to the resin layer of the object to be transferred using a roll-to-roll method. This makes it possible to continuously produce transferred objects that have the fine uneven structure 120 formed on the outer surface of the master disc 100 transferred onto them.

[0097] As shown in Figure 4, the transfer apparatus 300 comprises a master disc 100, a substrate supply roll 301, a winding roll 302, guide rolls 303 and 304, a nip roll 305, a peeling roll 306, a coating device 307, and a light source 309.

[0098] The substrate supply roll 301 is, for example, a roll on which a film-like substrate 311 is wound. The winding roll 302 is a roll for winding the film-like substrate 331 which has a resin layer 312 onto which the fine uneven structure 120 has been transferred. The guide rolls 303 and 304 are rolls for transporting the film-like substrate 311 before and after the transfer. The nip roll 305 is a roll for pressing the film-like substrate 311 with the resin layer 312 laminated onto it against the master plate 100. The peeling roll 306 is a roll for peeling the film-like substrate 311, on which the fine uneven structure 120 has been transferred to the resin layer 312, from the master plate 100.

[0099] The film-like substrate 311 may be the same substrate as the substrate 10 of the anti-reflective film 1 according to this embodiment (see Figure 1), or it may be a different substrate from the substrate 10. In the latter case, the anti-reflective film 1 may be manufactured by attaching the substrate 311 having a resin layer 312 onto which the fine uneven structure 120 has been transferred using the transfer apparatus 300 of Figure 4 to the surface of the substrate 10 of the anti-reflective film 1 (see Figure 1). For example, in this embodiment, the anti-reflective film 1 having the fine uneven structure 12 is constructed by attaching the film-like substrate 311 having the resin layer 312 onto which the fine uneven structure 120 has been transferred (see Figure 4) to the surface of the substrate 10 of the anti-reflective film 1 (see Figure 1).

[0100] The coating apparatus 307 is equipped with coating means such as a coater and coats the uncured photocurable resin composition onto the film-like substrate 311 to form a resin layer 312. The coating apparatus 307 may be, for example, a gravure coater, a wire bar coater, or a die coater. The light source 309 is a light source that emits light of a wavelength capable of curing the photocurable resin composition, and may be, for example, an ultraviolet lamp.

[0101] The uncured photocurable resin composition is the uncured resin composition described above, which hardens when irradiated with light of a predetermined wavelength.

[0102] Next, a method for producing a transfer product using the above-described transfer apparatus 300 will be explained.

[0103] First, a film-like substrate 311 is continuously fed from the substrate supply roll 301 and conveyed by the guide roll 303. Next, a photocurable resin composition is applied to the surface of the fed substrate 311 by the coating device 307, and an uncured resin layer 312 is laminated on the surface of the substrate 311.

[0104] Furthermore, the uncured resin layer 312 laminated on the surface of the substrate 311 is pressed against the outer surface of the master disc 100 by the nip roll 305. As a result, the fine uneven structure 120 formed on the outer surface of the master disc 100 is transferred to the uncured resin layer 312 (transfer step). At this time, the release layer formed on the surface of the fine uneven structure 120 of the master disc 100 causes silicone having acrylic functional groups to segregate onto the surface of the resin layer 312. Subsequently, the resin layer 312 to which the fine uneven structure 120 has been transferred is irradiated with light from the light source 309, such as ultraviolet light (curing step). As a result, the uncured resin layer 312 hardens, and the shape of the uneven pattern transferred to the cured resin layer 312 is stabilized. In addition, silicone having acrylic functional groups is segregated onto the surface of the cured resin layer 312 (fine uneven structure 12 of the optical functional layer 11).

[0105] Next, the substrate 311 on which the hardened resin layer 312 is laminated is peeled off from the outer surface of the master disc 100 by the peeling roll 306. As a result, a micro-textured structure 12 having the inverse shape of the micro-textured structure 120 of the master disc 100 is formed on the resin layer 312. After that, the substrate 311 peeled off from the master disc 100 is conveyed via the guide roll 304 and wound onto the winding roll 302.

[0106] In this way, using a roll-to-roll transfer apparatus 300, a transfer product (for example, the anti-reflective film 1 according to this embodiment) on which the fine uneven structure 120 formed on the master disc 100 has been transferred can be continuously manufactured. This makes it possible to manufacture a large quantity of transfer products on which the fine uneven structure 120 has been transferred with high precision, efficiently and at low cost.

[0107] [6. Examples of Application of Anti-Reflective Film] Next, examples of application of the anti-reflective film 1 according to this embodiment will be described.

[0108] As described above, the anti-reflective film 1 has excellent anti-reflective and anti-fogging properties. For this reason, the anti-reflective film 1 can be suitably applied to medical eye shields, medical face shields, industrial safety glasses, corrective glasses, sunglasses, swimming goggles, full-face helmets, smartphone cameras, camera cover glass for security cameras, displays such as in-car displays, vehicle windshields (e.g., the front of in-car cameras), in-car head-up displays, dust covers, refrigerator glass doors, VR goggle displays, VR goggle optics, VR goggle covers, and the surface of solar cells.

[0109] [7. Summary] The anti-reflective film 1 according to this embodiment has been described above. According to this embodiment, an anti-reflective film 1 is provided which comprises an optical functional layer 11 made of resin, the optical functional layer 11 has a fine uneven structure 12 including protrusions 13 or recesses 14 arranged at a pitch of less than or equal to the wavelength of visible light, the indentation modulus of the optical functional layer 11 is 45 MPa or more, the water absorption rate of the optical functional layer 11 is 11% by mass or more, and the water contact angle of the surface of the optical functional layer 11 is 65° or more. As a result, the anti-reflective film 1 according to this embodiment can suppress deformation of the fine uneven structure 12 due to water absorption and achieve both anti-fogging and anti-reflective functions. Therefore, the anti-reflective film 1 according to this embodiment can have anti-reflective function, high transparency, and anti-fogging function.

[0110] Furthermore, in this embodiment, the resin forming the optical functional layer 11 may consist of a cured product of an uncured resin composition, and the uncured resin composition may contain silicone having acrylic functional groups. This allows the silicone having acrylic functional groups to be segregated on the surface of the fine uneven structure 12 of the optical functional layer 11 during the transfer process. As a result, the anti-reflective film 1 according to this embodiment can improve the water contact angle of the surface of the fine uneven structure 12 of the optical functional layer 11.

[0111] Furthermore, in this embodiment, the Martens hardness of the optical functional layer 11 is preferably 3 MPa or higher. This allows the anti-reflective film 1 according to this embodiment to further suppress deformation of the fine uneven structure 12 due to water absorption.

[0112] Furthermore, in this embodiment, the resin forming the optical functional layer 11 may consist of a cured product of an uncured resin composition, and the uncured resin composition may contain an acrylate monomer having one or both of ethylene oxide groups and acrylamide groups. This allows the anti-reflective film 1 according to this embodiment to further improve the water absorption rate of the optical functional layer 11. Therefore, the anti-reflective film 1 according to this embodiment can exhibit a high anti-fogging function.

[0113] Furthermore, in this embodiment, the number of repeating units of the ethylene oxide group in the acrylate monomer having the ethylene oxide group may be 4 or more and 20 or less. As a result, the anti-reflective film 1 according to this embodiment can achieve both a high water absorption rate and a high indentation modulus in the optical functional layer 11. Therefore, the anti-reflective film 1 according to this embodiment can exhibit high anti-fogging function and high anti-reflective function.

[0114] Furthermore, in this embodiment, the content of acrylate monomers having ethylene oxide groups in the uncured resin composition may be 90% by mass or less. This prevents the anti-reflective film 1 according to this embodiment from whitening of the optical functional layer 11 itself when it absorbs water. Therefore, it is possible to prevent a decrease in the transparency of the optical functional layer 11.

[0115] Furthermore, in this embodiment, the content of acrylate monomers having acrylamide groups in the uncured resin composition may be 50% by mass or less. This allows the anti-reflective film 1 according to this embodiment to improve the scratch resistance and abrasion resistance of the optical functional layer 11.

[0116] Furthermore, in this embodiment, the resin forming the optical functional layer 11 may consist of a cured product of an uncured resin composition, and the uncured resin composition may contain a polyfunctional acrylate monomer. This allows the anti-reflective film 1 according to this embodiment to further improve the indentation modulus of the optical functional layer 11. Therefore, the anti-reflective film 1 according to this embodiment can further suppress deformation of the fine uneven structure 12 due to water absorption.

[0117] Furthermore, in this embodiment, the content of polyfunctional acrylate monomer in the uncured resin composition may be 10% by mass or more. This allows the anti-reflective film 1 according to this embodiment to further improve the indentation modulus of the optical functional layer 11.

[0118] Furthermore, in this embodiment, a base material 10 may be provided, and the optical functional layer 11 may be provided on the base material 10. This improves the ease of handling of the anti-reflective film 1 according to this embodiment.

[0119] Furthermore, in this embodiment, the optical functional layer 11 may also have an anti-fogging function. As a result, the anti-reflective film 1 according to this embodiment can be suitably applied to medical eye shields, industrial safety glasses, camera cover glass, and the like.

[0120] Furthermore, according to this embodiment, an eye shield equipped with an anti-reflective film 1 is provided. This makes it possible to provide an eye shield that has both anti-reflective and anti-fog functions.

[0121] Next, an anti-reflective film according to an embodiment of the present invention will be described. It should be noted that the following embodiments are merely examples to demonstrate the effects and feasibility of the anti-reflective film according to the present invention, and the present invention is not limited to these embodiments.

[0122] Anti-reflective films 1 of Examples 1 to 3 and anti-reflective films of Comparative Examples 1 to 4 were prepared. The anti-reflective films 1 of Examples 1 to 3 and the anti-reflective films of Comparative Examples 1 to 2 differ in the number of times the master disc 100 was used, but the substrate 10, the composition of the uncured resin composition, the content of each composition in the uncured resin composition, the thickness of the optical functional layer 11, and the manufacturing method are the same. Comparative Examples 3 to 4 differ from Comparative Example 1 in the composition of the uncured resin composition and the content of each composition in the uncured resin composition, but the substrate 10, the thickness of the optical functional layer, the manufacturing method, and the number of times the master disc 100 was used are the same.

[0123] Polyethylene terephthalate (PET) was used as the base material 10 for the anti-reflective films 1 in Examples 1 to 3 and the anti-reflective films in Comparative Examples 1 to 4. The thickness of the base material 10 was 100 μm. The base material 10 used was product name "A4360" manufactured by Toyobo Co., Ltd.

[0124] Then, a resin layer was formed by applying the uncured resin composition to the substrate 10, and the fine uneven structure 120 of the flat master plate 100 was transferred to the resin layer. At the same time, ultraviolet light was irradiated from the substrate 10 side to cure the resin layer. In this process, a metal halide lamp was used for ultraviolet irradiation, and the integrated light intensity was 200 mJ / m ２ The following was done. The pitch of the fine uneven structure 120 of the master disc 100 was set to 200 nm, and the height of the protrusions 123 was set to 250 nm. The arrangement of the multiple protrusions 123 of the fine uneven structure 120 of the master disc 100 was set to a quasi-hexagonal lattice arrangement. In addition, a release layer containing a fluoropolymer was pre-formed on the surface of the fine uneven structure 120 of the master disc 100. The release layer was formed by applying "Novec® 1720", a product manufactured by 3M Japan Ltd., to the surface of the fine uneven structure 120 of the master disc 100. In other words, the fine uneven structure 120 was transferred to the resin layer using the master disc 100, which had a release layer formed on its surface.

[0125] After the fine uneven structure 120 was transferred and the hardened resin layer was released from the master disc 100, ultraviolet light was further irradiated from the side of the fine uneven structure 12 of the optical functional layer 11. At this time, a metal halide lamp was used for ultraviolet irradiation, and the integrated light intensity was 500 mJ / m ２ The thickness of the optical functional layer 11 was set to 10 μm. In this way, the anti-reflective films 1 of Examples 1 to 3 and the anti-reflective films of Comparative Examples 1 to 4 were prepared.

[0126] The compositions of the uncured resin compositions used to create the anti-reflective films 1 of Examples 1 to 3 and the anti-reflective films of Comparative Examples 1 to 4 will be described below.

[0127] Furthermore, as the acrylate monomer having an ethylene oxide group, the trimethylolpropane EO-modified triacrylate shown in formula (3) above was used. As the trimethylolpropane EO-modified triacrylate, the product name "NK Ester AT-20E" manufactured by Shin Nakamura Chemical Industry Co., Ltd. was used.

[0128] As the acrylate monomer having an acrylamide group, N,N-dimethylacrylamide represented by formula (7) above was used. As the N,N-dimethylacrylamide, the product name "DMAA" manufactured by KJ Chemicals Co., Ltd. was used.

[0129] As the polyfunctional acrylate monomer, we used tricyclodecanedimethanol diacrylate shown in formula (15) above, or pentaerythritol triacrylate shown in formula (12) above and pentaerythritol tetraacrylate shown in formula (13) above. For tricyclodecanedimethanol diacrylate, we used the product name "NK Ester A-DCP" manufactured by Shin Nakamura Chemical Industry Co., Ltd. For pentaerythritol triacrylate and pentaerythritol tetraacrylate, we used the product name "NK Ester A-TMM-3L" manufactured by Shin Nakamura Chemical Industry Co., Ltd.

[0130] As another monomer, 2-hydroxy-3-phenoxypropyl acrylate was used. The 2-hydroxy-3-phenoxypropyl acrylate used was "Arronix M5700," a product manufactured by Toagosei Co., Ltd.

[0131] As the silicone having acrylic functional groups, an acrylic group-containing polyester-modified polydimethylsiloxane was used. The acrylic group-containing polyester-modified polydimethylsiloxane used was "BYK-UV3570," a product manufactured by BYK Corporation.

[0132] As a photopolymerization initiator, we used "Omnirad 127," a product manufactured by IGM Resins B.V.

[0133] [Example 1] The uncured resin composition of Example 1 was prepared to contain trimethylolpropane EO-modified triacrylate, N,N-dimethylacrylamide, tricyclodecanedimethanol diacrylate, acrylic group-containing polyester-modified polydimethylsiloxane, and further to include 2-hydroxy-3-phenoxypropyl acrylate and a photopolymerization initiator.

[0134] The content of trimethylolpropane EO-modified triacrylate in the uncured resin composition was 56% by mass. The content of N,N-dimethylacrylamide in the uncured resin composition was 12% by mass. The content of tricyclodecanedimethanol diacrylate in the uncured resin composition was 10% by mass. The content of 2-hydroxy-3-phenoxypropyl acrylate in the uncured resin composition was 22% by mass. Furthermore, when the total of trimethylolpropane EO-modified triacrylate, N,N-dimethylacrylamide, tricyclodecanedimethanol diacrylate, and 2-hydroxy-3-phenoxypropyl acrylate is set to 100% by mass, the content of acrylic group-containing polyester-modified polydimethylsiloxane in the uncured resin composition was set to 1% by mass, and the content of the photopolymerization initiator in the uncured resin composition was set to 3% by mass.

[0135] In Example 1, a release layer was formed on the surface of the master disc 100, and then the optical functional layer 11 was created by performing the first transfer using the master disc 100 (first transfer).

[0136] [Example 2] The uncured resin composition of Example 2, and the content of each component in the uncured resin composition, are the same as in Example 1.

[0137] In Example 2, a release layer was formed on the surface of the master disc 100, and then the master disc 100 was used to perform a transfer for the 50th time (50th transfer), thereby creating the optical functional layer 11.

[0138] [Example 3] The uncured resin composition of Example 3, and the content of each component in the uncured resin composition, are the same as in Example 1.

[0139] In Example 3, a release layer was formed on the surface of the master disc 100, and then the master disc 100 was used to perform a transfer for the 100th time (100th transfer), thereby creating the optical functional layer 11.

[0140] [Comparative Example 1] The uncured resin composition of Comparative Example 1, and the content of each component in the uncured resin composition, are the same as in Example 1.

[0141] In Comparative Example 1, a release layer was formed on the surface of the master disc 100, and then the master disc 100 was used to perform a transfer for the 150th time (150th transfer), thereby creating the optical functional layer 11.

[0142] [Comparative Example 2] The uncured resin composition of Comparative Example 2, and the content of each component in the uncured resin composition, are the same as in Example 1.

[0143] In Comparative Example 2, a release layer was formed on the surface of the master disc 100, and then the master disc 100 was used to perform a transfer for the 200th time (200th transfer), thereby creating the optical functional layer 11.

[0144] [Comparative Example 3] The uncured resin composition of Comparative Example 3 was prepared to contain trimethylolpropane EO-modified triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and a photopolymerization initiator. Furthermore, the uncured resin composition of Comparative Example 3 did not contain acrylate monomers having acrylamide groups or silicones having acrylic functional groups.

[0145] The content of trimethylolpropane EO-modified triacrylate in the uncured resin composition was 90% by mass. The content of pentaerythritol triacrylate and pentaerythritol tetraacrylate in the uncured resin composition was 10% by mass. Furthermore, the content of the photopolymerization initiator in the uncured resin composition was 3% by mass, assuming that the total of trimethylolpropane EO-modified triacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate was 100% by mass.

[0146] In Comparative Example 3, a release layer was formed on the surface of the master disc 100, and then the optical functional layer 11 was created by performing the transfer for the first time using the master disc 100 (first transfer).

[0147] [Comparative Example 4] The uncured resin composition of Comparative Example 4 was prepared to contain trimethylolpropane EO-modified triacrylate, 2-hydroxy-3-phenoxypropyl acrylate, and a photopolymerization initiator. Furthermore, the uncured resin composition of Comparative Example 4 did not contain acrylate monomers having acrylamide groups, polyfunctional acrylate monomers, or silicones having acrylic functional groups.

[0148] The content of trimethylolpropane EO-modified triacrylate in the uncured resin composition was 60% by mass. The content of 2-hydroxy-3-phenoxypropyl acrylate in the uncured resin composition was 40% by mass. Furthermore, the content of the photopolymerization initiator in the uncured resin composition was 3% by mass, assuming that the total of trimethylolpropane EO-modified triacrylate and 2-hydroxy-3-phenoxypropyl acrylate was 100% by mass.

[0149] In Comparative Example 4, a release layer was formed on the surface of the master disc 100, and then the optical functional layer 11 was created by performing the transfer for the first time using the master disc 100 (first transfer).

[0150] [Water Contact Angle] Table 1 shows the water contact angle, anti-fogging performance evaluation results, and whitening evaluation results for anti-reflective film 1 of Examples 1 to 3. Table 2 shows the water contact angle, anti-fogging performance evaluation results, and whitening evaluation results for anti-reflective films of Comparative Examples 1 to 4. In Tables 1 and 2, "A" indicates no fogging or no water film formation, and "C" indicates fogging or the spread of a water film.

[0151]

[0152]

[0153] The water contact angles of the surface of the micro-textured structure 12 of the anti-reflective film 1 in Examples 1 to 3 and the surface of the micro-textured structure 12 of the anti-reflective film in Comparative Examples 1 to 4 were measured. The water contact angles were measured using a contact angle meter by the droplet method under the following conditions: Amount of water dropped: 1.0 μL Measurement temperature: 25°C Based on the measurements taken 10 seconds after dropping water onto the surface of the optical functional layer 11 of the anti-reflective film 1 in Examples 1 to 3 and the anti-reflective film in Comparative Examples 1 to 4, the water contact angles of the surface of the optical functional layer 11 were calculated using the θ / 2 method.

[0154] For the contact angle meter, we used the "Contact Angle Meter DMe-700" manufactured by Kyowa Interface Chemical Co., Ltd.

[0155] As shown in Table 1, the water contact angle of Example 1 was 128°. The water contact angle of Example 2 was 90°. The water contact angle of Example 2 was 68°. Also, as shown in Table 2, the water contact angle of Comparative Example 1 was 51°. The water contact angle of Comparative Example 2 was 44°. From these results, it was confirmed that the water contact angle of the surface of the optical functional layer 11 decreases as the number of transfer cycles increases. Furthermore, Comparative Examples 1 and 2 had a larger number of transfer cycles compared to Examples 1 to 3. For this reason, it is presumed that in Comparative Examples 1 and 2, fluorine was detached from the release layer formed on the surface of the fine uneven structure 120 of the master disc 100, increasing the surface energy of the release layer, and thus preventing the silicone having acrylic functional groups from segregating on the surface of the fine uneven structure 12 of the optical functional layer 11 during the transfer process.

[0156] Furthermore, as shown in Table 2, the water contact angle of Comparative Example 3 was 30°. The water contact angle of Comparative Example 4 was 35°. From these results, it was confirmed that when the uncured resin composition does not contain silicone having acrylic functional groups, the water contact angle of the surface of the optical functional layer 11 is low. It is presumed that when the uncured resin composition does not contain silicone having acrylic functional groups, the silicone having acrylic functional groups is not segregated on the surface of the fine uneven structure 12 of the optical functional layer 11 during the transfer process, resulting in a lower water contact angle of the surface of the fine uneven structure 12 of the optical functional layer 11.

[0157] [Anti-fogging performance evaluation] The anti-fogging performance of the anti-reflective films 1 of Examples 1 to 3 and the anti-reflective films of Comparative Examples 1 to 4 was evaluated. For the anti-fogging performance evaluation, the anti-reflective films 1 of Examples 1 to 3 and the anti-reflective films of Comparative Examples 1 to 4 were examined by blowing exhaled air onto them from a distance of 1 cm from the mouth and visually checking the surface condition.

[0158] As shown in Table 1, Example 1 received an evaluation of "A". Example 2 also received an evaluation of "A". Example 3 also received an evaluation of "A". Furthermore, as shown in Table 2, Comparative Example 1 also received an evaluation of "A". Comparative Example 2 also received an evaluation of "A".

[0159] As shown in Table 2, Comparative Example 3 received an evaluation of "A". Comparative Example 4 received an evaluation of "C". Comparative Example 4 had a lower water absorption rate compared to Example 1. Therefore, it is presumed that Comparative Example 4 had lower anti-fogging properties than Example 1.

[0160] [Whitening Evaluation] Whitening evaluation was performed on the anti-reflective films 1 of Examples 1 to 3 and the anti-reflective films of Comparative Examples 1 to 4. For the whitening evaluation, the surface condition was visually checked after the anti-fogging evaluation described above. In Tables 1 and 2, "A" indicates that no whitening occurred, i.e., that the film remained transparent, and "C" indicates that whitening occurred.

[0161] As shown in Table 1, all of Examples 1 to 3 received an evaluation of "A". On the other hand, as shown in Table 2, all of Comparative Examples 1 to 5 received an evaluation of "C". Comparative Examples 1 and 2 had more transfer cycles compared to Examples 1 to 3. Therefore, it is presumed that in Comparative Examples 1 and 2, fluorine was detached from the release layer formed on the surface of the fine uneven structure 120 of the master disc 100, increasing the surface energy of the release layer, and thus preventing the silicone having acrylic functional groups from segregating on the surface of the fine uneven structure 12 of the optical functional layer 11 during the transfer process.

[0162] Furthermore, unlike Example 1, Comparative Example 3 does not contain silicone having acrylic functional groups in the uncured resin composition. Therefore, unlike Example 1, it is presumed that in Comparative Example 3, the silicone having acrylic functional groups was not segregated on the surface of the fine uneven structure 12 of the optical functional layer 11 during the transfer process, resulting in extremely low whitening resistance.

[0163] Furthermore, Comparative Example 4 has a lower indentation modulus compared to Example 1. Therefore, it is presumed that Comparative Example 4, unlike Example 1, has extremely low whitening resistance.

[0164] [Indentation modulus]

[0165] Samples for Examples 1A to 3A and Comparative Examples 1A to 4A were prepared. The samples for Examples 1A to 3A and Comparative Examples 1A to 4A differed in the composition of the uncured resin composition and the content of each composition in the uncured resin composition, but the manufacturing method was the same.

[0166] A 100 μm spacer was inserted between two soda-lime glass plates, and the uncured resin composition was filled in. The resin composition was then cured by irradiation with ultraviolet light. A metal halide lamp was used for the ultraviolet irradiation, with an integrated light intensity of 2000 mJ / m². ２ This was done. In this way, samples for Examples 1A to 3A and Comparative Examples 1A to 4A were prepared.

[0167] The uncured resin composition of Example 1A was the same as that of Example 1. The uncured resin composition of Example 2A was the same as that of Example 2. The uncured resin composition of Example 3A was the same as that of Example 3. Furthermore, the uncured resin composition of Comparative Example 1A was the same as that of Comparative Example 1. The uncured resin composition of Comparative Example 2A was the same as that of Comparative Example 2. The uncured resin composition of Comparative Example 3A was the same as that of Comparative Example 3. The uncured resin composition of Comparative Example 4A was the same as that of Comparative Example 4.

[0168] Table 3 shows the indentation modulus and Martens hardness of the samples from Examples 1A to 3A. Table 4 shows the indentation modulus and Martens hardness of the samples from Comparative Examples 1A to 4A.

[0169]

[0170]

[0171] The indentation modulus of the anti-reflective film 1 of Examples 1A to 3A and the anti-reflective film of Comparative Examples 1A to 4A were calculated.

[0172] The indentation modulus was calculated using the Oliver & Pharr method based on the unloading curve obtained by pressing a Vickers indenter against the surface of a sample using an indentation tester, fitted within a range of 40% to 98% of the maximum load. The indentation modulus was also calculated based on the unloading curve obtained under the conditions of a load of 0.5 mN / 10 seconds, holding time of 10 seconds, and unloading of 0.5 mN / 10 seconds. Anton Paar's nanoindentation tester, product name "Hit 300," was used as the indentation tester.

[0173] As shown in Table 3, the indentation modulus of Example 1A was 45 MPa. The indentation modulus of Example 2A was 45 MPa. The indentation modulus of Example 3A was 45 MPa. Also, as shown in Table 4, the indentation modulus of Comparative Example 1A was 45 MPa. The indentation modulus of Comparative Example 2A was 45 MPa.

[0174] As shown in Table 4, the indentation modulus of Comparative Example 3A was 126 MPa. The indentation modulus of Comparative Example 4A was 37 MPa.

[0175] Comparative Example 4A does not contain polyfunctional acrylate monomers in its uncured resin composition compared to Example 1A. Therefore, it is presumed that the indentation modulus of Comparative Example 4A is lower than that of Example 1A.

[0176] [Martens Hardness] The Martens hardness of anti-reflective film 1 of Examples 1A to 3A and the anti-reflective films of Comparative Examples 1A to 4A were calculated.

[0177] The Martens hardness was calculated by dividing the test load applied when a Vickers indenter was pressed against the surface of the sample using an indentation tester by the surface area into which the Vickers indenter penetrated the sample. The Martens hardness was also calculated under the conditions of a load of 0.5 mN / 10 seconds, a holding time of 10 seconds, and an unloading time of 0.5 mN / 10 seconds. Anton Paar's nanoindentation tester, product name "Hit 300," was used as the indentation tester.

[0178] As shown in Table 3, the Martens hardness of Example 1A was 3 MPa. The Martens hardness of Example 2A was 3 MPa. The Martens hardness of Example 3A was 3 MPa. Also, as shown in Table 4, the Martens hardness of Comparative Example 1A was 3 MPa. The Martens hardness of Comparative Example 2A was 3 MPa.

[0179] As shown in Table 4, the Martens hardness of Comparative Example 3A was 9.5 MPa. The Martens hardness of Comparative Example 4A was 3 MPa.

[0180] [Water Absorption Rate] Samples were prepared for Examples 1B to 3B and Comparative Examples 1B to 4B. The samples for Examples 1B to 3B and Comparative Examples 1B to 4B differed in the composition of the uncured resin composition and the content of each component in the uncured resin composition, but the manufacturing method was the same.

[0181] A 500 μm spacer was inserted between the soda-lime glass and the silicone rubber, and the uncured resin composition was filled in. The resin composition was then cured by irradiation with ultraviolet light. A metal halide lamp was used for the ultraviolet irradiation, with an integrated light intensity of 2000 mJ / m². ２ Then, the cured material was cut into 50 mm x 70 mm sheets to create samples for Examples 1B to 3B and Comparative Examples 1B to 4B.

[0182] The uncured resin composition of Example 1B was the same as that of Example 1. The uncured resin composition of Example 2B was the same as that of Example 2. The uncured resin composition of Example 3B was the same as that of Example 3. Furthermore, the uncured resin composition of Comparative Example 1B was the same as that of Comparative Example 1. The uncured resin composition of Comparative Example 2B was the same as that of Comparative Example 2. The uncured resin composition of Comparative Example 3B was the same as that of Comparative Example 3. The uncured resin composition of Comparative Example 4B was the same as that of Comparative Example 4.

[0183] Table 5 shows the water absorption rates of the samples from Examples 1B to 3B and Comparative Examples 1B to 4B.

[0184]

[0185] The water absorption rates of the samples from Examples 1B to 3B and Comparative Examples 1B to 4B were calculated using the procedure shown in Figure 2 above.

[0186] As shown in Table 5, the water absorption rate of Example 1B was 19.4%. The water absorption rate of Example 2B was 19.4%. The water absorption rate of Example 3B was 19.4%. Also, as shown in Table 5, the water absorption rate of Comparative Example 1B was 19.4%. The water absorption rate of Comparative Example 2B was 19.4%.

[0187] As shown in Table 5, the water absorption rate of Comparative Example 3B was 23.7%. The water absorption rate of Comparative Example 4B was 10.5%. Comparative Example 3B has a higher content of acrylate monomers having ethylene oxide groups in the uncured resin composition compared to Example 1B. Therefore, it is presumed that the water absorption rate of Comparative Example 3B was higher than that of Example 1B.

[0188] Although preferred embodiments of the present invention have been described in detail above with reference to the attached drawings, the present invention is not limited to these examples. It is clear to any person with ordinary skill in the art to which the present invention belongs that various modifications or alterations can be conceived within the scope of the technical idea described in the claims, and these are also understood to fall within the technical scope of the present invention.

[0189] 1 Anti-reflective film 10 Substrate 100 Master disc 11 Optical functional layer 12 Micro-textured structure 13 Protrusions 14 Recesses

Claims

1. An anti-reflective film comprising an optical functional layer formed of resin, wherein the optical functional layer has a fine uneven structure including protrusions or recesses arranged at a pitch less than or equal to the wavelength of visible light, the indentation modulus of the optical functional layer is 45 MPa or more, the water absorption rate of the optical functional layer is 11% by mass or more, and the water contact angle of the surface of the optical functional layer is 65° or more.

2. The anti-reflective film according to claim 1, wherein the resin forming the optical functional layer is made from a cured product of an uncured resin composition, and the uncured resin composition contains silicone having acrylic functional groups.

3. The anti-reflective film according to claim 1 or 2, wherein the Martens hardness of the optical functional layer is 3 MPa or more.

4. The anti-reflective film according to claim 1 or 2, wherein the resin forming the optical functional layer is made from a cured product of an uncured resin composition, and the uncured resin composition comprises an acrylate monomer having one or both of an ethylene oxide group and an acrylamide group.

5. The anti-reflective film according to claim 4, wherein the repeating units of the ethylene oxide group in the acrylate monomer having the ethylene oxide group are 4 or more and 20 or less.

6. The anti-reflective film according to claim 4, wherein the content of the acrylate monomer having an ethylene oxide group in the uncured resin composition is 90% by mass or less.

7. The anti-reflective film according to claim 4, wherein the content of acrylate monomers having acrylamide groups in the uncured resin composition is 50% by mass or less.

8. The anti-reflective film according to claim 1 or 2, wherein the resin forming the optical functional layer is made from a cured product of an uncured resin composition, and the uncured resin composition comprises a polyfunctional acrylate monomer.

9. The anti-reflective film according to claim 8, wherein the content of polyfunctional acrylate monomer in the uncured resin composition is 10% by mass or more.

10. The anti-reflective film according to claim 1 or 2, further comprising a substrate, wherein the optical functional layer is provided on the substrate.

11. The anti-reflective film according to claim 1 or 2, wherein the optical functional layer has an anti-fogging function.

12. An eye shield comprising the anti-reflective film described in claim 1 or 2.

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