Photocurable acrylic resin for imprinting, and method for producing photocurable acrylic resin for imprinting

Abstract

This photocurable acrylic resin for imprinting comprises a photopolymerizable component, wherein the photopolymerizable component comprises a resin (A) and a resin (B), the resin (A) is a monofunctional acrylate monomer having a phenyl group and / or a benzyl group, the resin (B) is a difunctional compound, the content of the resin (A) is 20 mass% to 42 mass% with respect to the total amount of the photopolymerizable component, and the content of the resin (B) is 43 mass% to 66 mass% with respect to the total amount of the photopolymerizable component.

Description

Photocurable acrylic resin for imprinting, and method for manufacturing photocurable acrylic resin for imprinting

[0001] The present invention relates to a photocurable acrylic resin used in imprint molding, and a method for manufacturing a photocurable acrylic resin for imprinting. This application claims priority under Japanese Patent Application No. 2024-225958, filed on 23 December 2024, the contents of which are incorporated herein by reference.

[0002] As a technique for manufacturing resin optical components having a fine uneven structure, imprint molding onto an uncured resin layer composed of an uncured resin composition is widely used. In imprint molding, the fine uneven shape of a master plate is pressed onto an uncured resin layer formed on a substrate, the uncured resin layer is cured in that state, and the master plate is peeled off to form the fine uneven shape on the substrate.

[0003] In imprint molding, if the thickness of the uncured resin layer (layer thickness) when the master disc is pressed is uneven, the peeling force applied when peeling the master disc from the cured resin layer (hereinafter referred to as the "cured resin layer") will be uneven within the plane of the cured resin layer. This may cause a portion of the cured resin layer to peel off from the substrate. Furthermore, if the cured resin layer that has peeled off from the substrate remains on the master disc, the master disc cannot be reused. In addition, when peeling off the master disc, the fine irregularities transferred to the cured resin layer may be deformed, potentially reducing the optical properties caused by the fine irregularities.

[0004] Furthermore, in imprint molding, if the uncured resin composition does not conform well to the fine uneven surface when the master plate is pressed against it, there will be areas in the uncured resin layer where the fine uneven surface of the master plate is not transferred.

[0005] Therefore, techniques have been developed to lower the viscosity of the uncured resin composition in order to make the thickness of the uncured resin layer uniform when the master plate is pressed against it, and to improve the conformability of the uncured resin composition to fine uneven shapes (for example, Patent Documents 1 and 2).

[0006] Japanese Patent Publication No. 2018-125559, Japanese Patent No. 4824068

[0007] To lower the viscosity of the uncured resin composition, it is possible to increase the content of monofunctional monomers and low-viscosity difunctional monomers in the resin composition.

[0008] However, increasing the content of monofunctional monomers and low-viscosity difunctional monomers presents a problem: it reduces the heat resistance of the cured resin layer.

[0009] Therefore, the present invention has been made in view of these circumstances, and aims to provide a photocurable acrylic resin for imprinting that has a low viscosity in the uncured resin composition and excellent heat resistance in the cured resin composition, and a method for producing a photocurable acrylic resin for imprinting.

[0010] To solve the above problems, according to one aspect of the present invention, a photocurable acrylic resin for imprinting containing a photopolymerization component is provided, wherein the photopolymerization component comprises resin (A) and resin (B), wherein resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, and resin (B) is a bifunctional compound, the content of resin (A) to the total photopolymerization component is 20% by mass or more and 42% by mass or less, and the content of resin (B) to the total photopolymerization component is 43% by mass or more and 66% by mass or less.

[0011] The photopolymerization component may further contain a resin (C), wherein the resin (C) is an acrylate monomer having three or more functional groups, and the content of the resin (C) relative to the entire photopolymerization component may be 1% by mass or more and 30% by mass or less.

[0012] The resin (A) may be one or both of phenylethyl acrylate and benzyl acrylate.

[0013] The resin (B) may be one or more selected from the group consisting of (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate, (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid, and 1,6-hexanediol diacrylate.

[0014] The resin (B) may contain one of the following: 1,6-hexanediol diacrylate, (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate, and (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid.

[0015] The resin (C) may contain one or both of dipentaerythritol hexaacrylate and tris-(2-acryloxyethyl) isocyanurate.

[0016] The viscosity of the photocurable acrylic resin for imprinting at 25°C may be 90 mPa·s or less.

[0017] After holding the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the YI value of the cured product may be 3 or less.

[0018] At 30°C, the storage modulus of the cured product of the photocurable acrylic resin for imprinting is 2.0 × 10⁻⁶. ９ The pressure is Pa or higher, and the storage modulus of the cured product at 120°C is 1.3 × 10⁻⁶. ８ It may also be assumed to be Pa or greater.

[0019] The storage modulus of the cured product at 130°C is 1.4 × 10⁻⁶. ８ It may also be assumed to be Pa or greater.

[0020] After holding the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the average transmittance of the cured product to light in the wavelength range of 430 nm to 680 nm may be 91% or more, and the average transmittance of the cured product to light in the wavelength range of 430 nm to 510 nm may be 90% or more.

[0021] To solve the above problems, according to one aspect of the present invention, a method for producing a photocurable acrylic resin for imprinting, comprising a photopolymerization component and a photopolymerization initiator for polymerizing the photopolymerization component, wherein the photopolymerization component comprises resin (A) and resin (B), the resin (A) being a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, the resin (B) being a bifunctional compound, the content of resin (A) to the total photopolymerization component being 20% ​​by mass or more and 42% by mass or less, the content of resin (B) to the total photopolymerization component being 43% by mass or more and 66% by mass or less, and the method for producing a photocurable acrylic resin for imprinting comprising mixing resin (A) and resin (B), and mixing the photopolymerization initiator into the mixed resin of resin (A) and resin (B).

[0022] To solve the above problems, according to another aspect of the present invention, a method for producing a photocurable acrylic resin for imprinting containing a photopolymerization component, wherein the photopolymerization component comprises resin (A), resin (B), and resin (C), wherein resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, resin (B) is a bifunctional compound, resin (C) is an acrylate monomer having three or more functional groups, the content of resin (A) to the total photopolymerization component is 20% by mass or more and 42% by mass or less, the content of resin (B) to the total photopolymerization component is 43% by mass or more and 66% by mass or less, and the content of resin (C) to the total photopolymerization component is 1% by mass or more and 30% by mass or less, and a first mixed resin is produced by mixing resin (A) and resin (B), and a second mixed resin is produced by mixing resin (C) to the first mixed resin. A method for producing a photocurable acrylic resin for imprinting is provided, including the following.

[0023] According to the present invention, it is possible to provide a photocurable acrylic resin for imprinting that has a low viscosity in the uncured resin composition and excellent heat resistance in the cured resin composition.

[0024] Figure 1 is a schematic cross-sectional view showing a wire grid polarizing element according to an embodiment of the present invention. Figure 2 is a schematic plan view showing the wire grid polarizing element according to the same embodiment. Figure 3 is a process diagram showing a method for manufacturing the wire grid polarizing element according to the same embodiment.

[0025] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations will be omitted. For the sake of convenience of explanation, the states of the components disclosed in the following figures are sometimes schematically represented with a different scale and shape than the actual ones.

[0026] <1. Overview of Wire Grid Polarizing Element> First, an overview of the wire grid polarizing element 1 to which the imprintable photocurable acrylic resin according to the present invention is applied will be described with reference to Figures 1 and 2, etc. Figure 1 is a schematic cross-sectional view showing the wire grid polarizing element 1 according to this embodiment. Figure 2 is a schematic plan view showing the wire grid polarizing element 1 according to this embodiment.

[0027] The wire grid polarizing element 1 according to this embodiment is a reflective polarizing element and a wire grid type polarizing element. The wire grid polarizing element 1 may be, for example, a plate-shaped wire grid polarizing plate. The wire grid polarizing plate is a wire grid type polarizing plate having a plate shape. The wire grid polarizing plate may be, for example, a flat plate or a curved plate. In other words, the surface (the surface to which light is incident) of the wire grid polarizing element 1 may be a flat surface or a curved surface. Below, an example in which the wire grid polarizing element 1 according to this embodiment is a flat wire grid polarizing plate will be described, but the wire grid polarizing element of the present invention is not limited to such an example and can have any shape depending on its application and function.

[0028] The wire grid polarizing element of the present invention may be used, for example, as a polarizer that transmits only light vibrating in a specific direction, or as a polarizing beam splitter that separates incident light into a first polarization (S polarization) and a second polarization (P polarization). Below, an example in which the wire grid polarizing element 1 according to this embodiment is used as a polarizing beam splitter will be mainly described.

[0029] As shown in Figures 1 and 2, the wire grid polarizing element 1 (hereinafter sometimes abbreviated as "polarizing element 1") comprises a transparent substrate 10, a transparent grid structure 20, and an opaque functional film (for example, a reflective film 30).

[0030] In this specification, "transparent" means that the transmittance of light with a wavelength λ belonging to the usage band (e.g., the visible light band, the infrared light band, or the visible and infrared light bands) is high, for example, that the transmittance of such light is 70% or more. The wavelength band of visible light is, for example, 360 nm or more and 830 nm or less. The wavelength band of infrared light is larger than the wavelength band of visible light, for example, 830 nm or more. From the viewpoint of a suitable wavelength range of visible light projected as a display image, the wavelength λ of the usage band in the polarizing element 1 according to this embodiment is preferably, for example, 400 nm or more and 800 nm or less, and more preferably 420 nm or more and 680 nm or less. Since the polarizing element 1 according to this embodiment is formed of a material that is transparent to light in the usage band, it does not adversely affect the polarization characteristics or light transmittance of the polarizing element 1.

[0031] The substrate 10 is made of a transparent inorganic material such as glass. The substrate 10 is a flat plate-shaped substrate having a predetermined thickness TS.

[0032] The grid structure 20 is made of a transparent organic material, such as an organic resin material such as a cured product of a heat-resistant photocurable acrylic resin for imprinting. The grid structure 20 has an uneven structure to realize the polarization function of the polarizing element 1. Specifically, the grid structure 20 has a base portion 21 provided along the surface of the substrate 10 and a plurality of protruding portions 22 that project in a grid pattern from the base portion 21. The base portion 21 and the plurality of protruding portions 22 of the grid structure 20 are integrally formed using the same organic material.

[0033] The base portion 21 is a thin film having a predetermined thickness TB, and is laminated over the entire main surface (XY plane shown in Figures 1 and 2) of the substrate 10. Preferably, the thickness TB of the base portion 21 is substantially the same over the entire main surface of the substrate 10, but it does not have to be exactly the same thickness, and may vary to a certain extent with respect to a reference thickness of TB. For example, TB may vary by about ±3 μm with respect to a reference thickness of 6 μm. In this way, the thickness TB of the base portion 21 is determined while allowing for molding errors when forming the base portion 21 by imprinting or the like.

[0034] Multiple protrusions 22 are arranged on the base portion 21 at equal intervals in the X direction with a predetermined pitch P. The pitch P is the spacing between the multiple protrusions 22 arranged in the X direction of the polarizing element 1. The multiple protrusions 22 are arranged in a grid pattern, extending parallel to each other in the Y direction. A predetermined gap is formed between two adjacent protrusions 22 in the X direction. This gap serves as the entry path for incident light. Each protrusion 22 is a wall-shaped projection that extends elongated in a predetermined direction (the Y direction shown in Figures 1 and 2). The height (H) in the Z direction and the width (W) in the X direction of the multiple protrusions 22 are... Ｔ , W Ｂ These are substantially identical to each other. The longitudinal direction (Y direction) of the convex portion 22 is the direction of the reflection axis of the polarizing element 1, and the width direction (X direction) of the convex portion 22 is the direction of the transmission axis of the polarizing element 1.

[0035] The functional film is a film that imparts a predetermined function to the grid structure 20 of the polarizing element 1. The functional film is made of, for example, an opaque metallic material and is provided so as to cover a part of the raised ridge portion 22 of the grid structure 20. The functional film may be, for example, a reflective film 30 that has the function of reflecting incident light incident on the polarizing element 1, or an absorbing film (not shown) that has the function of absorbing the incident light, or a film with other functions. In this embodiment, an example in which the functional film is a reflective film 30 is described, but the functional film of the present invention is not limited to the example of a reflective film 30.

[0036] The reflective film 30 is a thin film made of a metallic material (such as a metal or metal oxide), for example, aluminum or silver. The reflective film 30 is formed to cover at least the top of the raised ridge portion 22. The reflective film 30 may also be composed of a metallic film that functions as a metal fine wire of the wire grid. The reflective film 30 has the function of reflecting incident light that enters the grid structure 20.

[0037] The protruding portions 22 of the grid structure 20 and the reflective film 30 constitute the grid of the wire grid polarizing element 1. The pitch P in the X direction of the multiple protruding portions 22 in the grid structure 20 (i.e., the grid arrangement pitch) is set to a pitch small compared to the wavelength λ of the incident light (e.g., visible light) (for example, less than half). As a result, the polarizing element 1 can reflect almost all of the light (S-polarized) with an electric field vector component vibrating in a direction parallel to the reflective film 30 (conductor wire) extending in the Y direction (reflection axis direction: Y direction), and transmit almost all of the light (P-polarized) with an electric field vector component vibrating in a direction perpendicular to the reflective film 30 (conductor wire) (transmission axis direction: X direction).

[0038] As described above, the wire grid polarizing element 1 according to this embodiment achieves polarization function by combining a grid structure 20 having a fine uneven structure and a functional film (e.g., a reflective film 30) selectively added to the raised ridges 22 of the grid structure 20. The substrate 10 of the wire grid polarizing element 1 is made of an inorganic material such as glass with excellent heat resistance, and the grid structure 20 is made of an organic resin material with heat resistance. Thus, the wire grid polarizing element 1 according to this embodiment is a hybrid polarizing element that combines organic and inorganic materials. Therefore, the thermal resistance R [m ２ • Because heat can be efficiently dissipated from the grid structure 20 with a small [K / W] to the substrate 10, it has excellent heat dissipation properties. Therefore, the hybrid wire grid polarizing element 1 according to this embodiment has superior heat resistance and heat dissipation compared to conventional film-type polarizing elements made only of organic materials (heat resistance: about 100°C), and has heat resistance in high-temperature environments up to about 200°C, for example. Thus, it can achieve excellent polarization characteristics while maintaining a good heat dissipation effect.

[0039] Furthermore, as described above, the grid structure 20, in which the base portion 21 and the raised ridge portion 22 are integrally formed, can be manufactured using printing technology such as nanoimprint, thus enabling the realization of a fine uneven structure with a simple manufacturing process. Therefore, the cost and effort required to manufacture the grid structure 20 can be reduced compared to manufacturing using photolithography or etching technology. Thus, the hybrid polarizing element 1 according to this embodiment has the advantage of significantly reducing manufacturing costs compared to conventional polarizing elements made only of inorganic materials, and thus enabling a lower unit price for the wire grid polarizing element 1.

[0040] As described above, the wire grid polarizing element 1 according to this embodiment has excellent heat resistance and heat dissipation, reduced manufacturing costs, and excellent transmittance and polarization separation characteristics for obliquely incident light at a wide range of large incident angles θ. Therefore, the wire grid polarizing element 1 according to this embodiment can be suitably applied as a variety of components in a variety of products. For example, the polarizing element 1 can be applied to polarizing beam splitters installed in smart displays. The polarizing element 1 can also be applied to polarizing elements that are protected from heat from sunlight, polarizing elements that are protected from heat from LED light sources, and polarizing reflective mirrors installed in head-up displays (HUDs). Furthermore, the polarizing element 1 can be applied to polarizing beam splitters installed in headlights such as adjustable beam distribution headlamps (ADBs). In addition, the polarizing element 1 can be applied to lens-integrated phase difference elements, lens-integrated polarizing elements, etc., installed in various devices for augmented reality (AR) or virtual reality (VR).

[0041] <2. Components of the Wire Grid Polarizing Element> Next, the components of the wire grid polarizing element 1 according to this embodiment will be described in detail with reference to Figures 1 and 2, etc.

[0042] <2.1. Substrate> As shown in Figure 1, the wire grid polarizing element 1 according to this embodiment includes a transparent substrate 10. The substrate 10 is made of an inorganic material that is transparent and has a certain degree of strength.

[0043] From the viewpoint of obtaining better heat dissipation and heat resistance, the material of the substrate 10 is preferably an inorganic material such as various types of glass, quartz, crystal, or sapphire, more preferably an inorganic material with a thermal conductivity of 1.0 W / m·K or higher, and even more preferably an inorganic material with a thermal conductivity of 8.0 W / m·K or higher.

[0044] Furthermore, the shape of the substrate 10 is not particularly limited and can be appropriately selected according to the performance required of the polarizing element 1. For example, it can be configured to be plate-shaped or curved. Also, from the viewpoint of not affecting the polarization characteristics of the polarizing element 1, the surface of the substrate 10 can be flat. Furthermore, the thickness TS of the substrate 10 is not particularly limited and can be in the range of, for example, 0.02 to 10.0 mm.

[0045] <2.2. Grid Structure> As shown in Figures 1 and 2, the polarizing element 1 according to this embodiment includes a grid structure 20 on a substrate 10, having the base portion 21 and a grid-like raised portion 22. The grid structure 20 can obtain desired polarization characteristics by providing a reflective film 30, which will be described later, on the raised portion 22.

[0046] When light is incident on the polarizing element 1 from the surface side where the grid structure 20 is formed, a portion of the incident light is reflected by the reflective film 30. Of the light incident on the reflective film 30, light with an electric field component in a direction perpendicular to the longitudinal direction of the convex portion 22 (i.e., the extension direction of the convex portion 22 = reflection axis direction: Y direction) (i.e., the width direction of the convex portion 22 = transmission axis direction: X direction) is transmitted through the polarizing element 1 with high transmittance. On the other hand, of the light incident on the reflective film 30, light with an electric field component in a direction parallel to the longitudinal direction of the convex portion 22 (i.e., the extension direction of the convex portion 22 = reflection axis direction: Y direction) is mostly reflected by the reflective film 30. Therefore, in this embodiment, by providing a grid structure 20 partially covered with the reflective film 30, single polarization can be produced. A similar polarization effect can also be obtained for light incident on the back side of the substrate 10.

[0047] As shown in Figure 1, the grid structure 20 has a base portion 21. The base portion 21 is a thin film provided along the surface of the substrate 10 and is a portion for supporting the raised ridges 22. When the uneven structure (raised ridges 22) of the grid structure 20 is formed by nanoimprinting or the like, the base portion 21 is inevitably formed. The base portion 21 and the raised ridges 22 are integrally formed from the same material. Furthermore, because the grid structure 20 has a base portion 21, the strength of the raised ridges 22 can be increased compared to when the raised ridges 22 are formed directly on the substrate 10. Therefore, the durability of the grid structure 20 can be increased. In addition, because the base portion 21 is in close contact with the substrate 10 over its entire surface, the peel resistance of the grid structure 20 can be increased.

[0048] The thickness TB of the base portion 21 is not particularly limited, but from the viewpoint of more reliably supporting the raised ridge portion 22 and facilitating imprint molding, it is preferably 1 nm or more, and more preferably 10 nm or more. Furthermore, from the viewpoint of ensuring good heat dissipation, the thickness TB of the base portion 21 is preferably 50 μm or less, and more preferably 30 μm or less.

[0049] Furthermore, according to the polarizing element 1 of this embodiment, since the base portion 21 and the plurality of protrusions 22 of the grid structure 20 are formed directly on the substrate 10, the thickness TB of the base portion 21 can be made thinner. Here, in order to improve the heat dissipation from the grid structure 20 to the substrate 10, it is preferable to reduce the temperature difference ΔT [°C] between the front and back surfaces of the base portion 21 by making the thickness TB of the base portion 21 thinner. The temperature difference ΔT is the temperature difference between the temperature T1 [°C] of the outermost surface of the base portion 21 (the base of the plurality of protrusions 22) and the temperature T2 [°C] of the base portion 21 at the interface between the base portion 21 and the substrate 10 (ΔT = T1 - T2).

[0050] Therefore, the thickness TB of the base portion 21 is preferably 0.15 mm or less. This allows heat from the grid structure 20 made of organic material to be quickly transferred to the substrate 10 made of inorganic material, and efficiently released from the substrate 10 to the outside of the polarizing element 1, thereby enabling heat dissipation and reducing the temperature difference ΔT to, for example, 32°C or less. Furthermore, the thickness TB of the base portion 21 is more preferably 0.09 mm or less, which allows the temperature difference ΔT to be, for example, 20°C or less. Furthermore, the thickness TB of the base portion 21 is more preferably 0.045 mm or less, which allows the temperature difference ΔT to be, for example, 10°C or less. Furthermore, the thickness TB of the base portion 21 is particularly preferably 0.02 mm or less, which allows the temperature difference ΔT to be, for example, 5°C or less. In this way, by reducing the thickness TB of the base portion 21, the heat dissipation from the grid structure 20 to the outside via the substrate 10 can be improved, thereby improving the heat dissipation and heat resistance of the polarizing element 1.

[0051] Furthermore, as shown in Figures 1 and 2, the grid structure 20 has a plurality of protruding ridges 22 that extend from the base portion 21. The protruding ridges 22 extend along the reflection axis direction (Y direction) of the polarizing element 1 according to this embodiment. A grid-like uneven structure is formed when the plurality of protruding ridges 22 are arranged at a predetermined pitch in the X direction and at predetermined intervals from one another.

[0052] Here, as shown in Figure 1, in the longitudinal section (XZ section) perpendicular to the reflection axis direction (Y direction) of the polarizing element 1, the pitch P of the convex portion 22 in the transmission axis direction (X direction) must be shorter than the wavelength of light in the usable band. The reason for this is to obtain the polarization effect described above. More specifically, the pitch P of the convex portion 22 is preferably 50 to 300 nm, more preferably 100 to 200 nm, and particularly preferably 100 to 150 nm, from the viewpoint of balancing ease of manufacturing of the convex portion 22 with polarization characteristics.

[0053] Furthermore, as shown in Figures 1 and 2, the width W of the bottom of the protruding portion 22 in the longitudinal section (XZ section) is also shown. ＢAlthough not particularly limited, from the viewpoint of achieving both ease of manufacturing and polarization characteristics, it is preferably about 10 to 150 nm, and more preferably about 10 to 100 nm. Further, the width W of the top of the convex strip portion 22 Ｔ Although not particularly limited, from the viewpoint of achieving both ease of manufacturing and polarization characteristics, it is preferably about 5 to 60 nm, and more preferably about 10 to 30 nm.

[0054] Incidentally, the width W of the bottom of the convex strip portion 22 Ｂ and the width W of the top Ｔ can be measured by observing with a scanning electron microscope or a transmission electron microscope. For example, a cross-section (XZ cross-section) orthogonal to the absorption axis direction or the reflection axis direction of the polarization element 1 is observed using a scanning electron microscope or a transmission electron microscope, and for any four convex strip portions 22, the width of the convex strip portion 22 at a height position 20% above the height H of the convex strip portion 22 from the bottom of the convex strip portion 22 is measured, and the arithmetic mean value thereof is defined as the width W of the bottom of the convex strip portion 22 Ｂ can be obtained. Further, for the above-mentioned arbitrary four convex strip portions 22, the width of the convex strip portion 22 at a height position 20% below the height H of the convex strip portion 22 from the tip 22a of the convex strip portion 22 is measured, and the arithmetic mean value thereof is defined as the width W of the top of the convex strip portion 22 Ｔ can be obtained.

[0055] Further, as shown in FIG. 1, the height H of the convex strip portion 22 in the longitudinal cross-section (XZ cross-section) is not particularly limited, but from the viewpoint of achieving both ease of manufacturing and polarization characteristics, it is preferably about 50 to 350 nm, and more preferably about 100 to 300 nm. Incidentally, the height H of the convex strip portion 22 can be measured by observing with a scanning electron microscope or a transmission electron microscope. For example, a cross-section orthogonal to the absorption axis direction or the reflection axis direction of the polarization element 1 is observed using a scanning electron microscope or a transmission electron microscope, and for the convex strip portion 22 at any four locations, the height of the convex strip portion 22 at the center position in the width direction of the convex strip portion 22 is measured, and the arithmetic mean value thereof can be defined as the height H of the convex strip portion 22.

[0056] The shape of the protruding portion 22 of the grid structure 20 is preferably tapered in order to obtain good polarization separation characteristics for obliquely incident light. Here, a tapered shape is a shape in which the width W (width in the X direction in the XZ cross section) of the protruding portion 22 gradually narrows as it moves away from the base portion 21, or in other words, a shape in which the width W of the protruding portion 22 gradually narrows as it moves from the bottom to the top of the protruding portion 22. Therefore, when the protruding portion 22 has a tapered shape, the width W of the top of the protruding portion 22 Ｔ The width W of the bottom of the protruding ridge 22 is Ｂ It becomes smaller (W Ｔ <W Ｂ ).

[0057] Furthermore, the method for forming the grid structure 20 can be a method for forming uneven surfaces such as imprinting. Among these, it is preferable to form the base portion 21 and the raised ridge portion 22 of the grid structure 20 by imprinting, from the viewpoint of being able to form an uneven pattern quickly and easily, and furthermore, to be able to reliably form the base portion 21.

[0058] When forming the base portion 21 and the raised portion 22 of the grid structure 20 by nanoimprint, for example, a photocurable acrylic resin for imprinting (grid structure material) for forming the grid structure 20 is applied to the substrate 10, and then a master plate with the uneven surface is pressed against the grid structure material. In this state, ultraviolet light or heat is applied to cure the grid structure material. This makes it possible to form a grid structure 20 having the base portion 21 and the raised portion 22. Details of the photocurable acrylic resin for imprinting will be described later.

[0059] <2.3. Reflective Film (Functional Film)> As shown in Figures 1 and 2, the polarizing element 1 according to this embodiment includes a reflective film 30 formed on the raised ridge portion 22 of the grid structure 20.

[0060] As shown in Figure 1, the reflective film 30 is formed to cover a portion of the tip 22a and side surface 22b of the protruding portion 22 of the grid structure 20. Furthermore, as shown in Figure 1, the reflective film 30 is formed to extend along the longitudinal direction (Y direction) of the protruding portion 22 of the grid structure 20. As a result, the reflective film 30 can reflect light that has an electric field component in a direction parallel to the longitudinal direction of the protruding portion 22 (reflection axis direction: Y direction) of the light incident on the polarizing element 1.

[0061] The material constituting the reflective film 30 is not particularly limited as long as it is a material that reflects light in the operating frequency band. Examples include individual metallic elements such as Al, Ag, Cu, Mo, Cr, Ti, Ni, W, Fe, Si, Ge, and Te, or metallic materials such as alloys containing one or more of these elements.

[0062] The reflective film 30 may be a single layer made of the above-mentioned metal, or a multilayer film made of multiple metal films. Furthermore, the reflective film 30 may include other layers, such as dielectric films, as needed, as long as it has a reflective function. The dielectric film is a thin film made of a dielectric material. The material of the dielectric film is SiO ２ Al ２ O ３ MgF ２ , TiO ２ Common materials such as those listed above can be used. Furthermore, the refractive index of the dielectric film is preferably greater than 1.0 and 2.5 or less. Note that the optical properties of the reflective film 30 are also affected by the surrounding refractive index; therefore, the polarization properties may be controlled by the material of the dielectric film.

[0063] <3. Method for Manufacturing a Polarizing Element> Next, the method for manufacturing the wire grid polarizing element 1 according to this embodiment will be described with reference to Figure 3. Figure 3 is a process diagram showing the method for manufacturing the wire grid polarizing element 1 according to this embodiment.

[0064] As described above, the polarizing element 1 according to this embodiment is a hybrid wire grid polarizing element 1 consisting of an inorganic material (substrate 10) and an organic material (grid structure 20). The manufacturing method of the hybrid wire grid polarizing element 1 will be described below.

[0065] As shown in Figure 3, the method for manufacturing the wire grid polarizing element 1 according to this embodiment includes a grid structure material formation step (S10), a nanoimprint step (S12), a grid structure formation step (S14), and a reflective film formation step (S16).

[0066] Grid structure material formation process (S10) First, in S10, a grid structure material 23 made of a transparent organic material (photocurable acrylic resin for imprinting) is laminated onto a substrate 10 made of a transparent inorganic material (for example, glass) by coating or the like. Any of the above-mentioned materials can be used as the inorganic material for the substrate 10. Furthermore, the film thickness of the grid structure material 23 can be appropriately adjusted according to the dimensions of the base portion 21 and the raised portion 22 of the grid structure 20 formed by nanoimprinting in S20.

[0067] Nanoimprint process (S12) and grid structure formation process (S14) Next, in S12, the grid structure material 23 is subjected to nanoimprinting, and in S14, the grid structure 20 is formed on the substrate 10. The grid structure 20 is a fine uneven structure in which a base portion 21 provided on the substrate 10 and a plurality of protruding ridges 22 protruding from the base portion 21 are integrally formed. The fine uneven structure is a structure having fine protrusions and recesses on the order of several nanometers to tens of nanometers.

[0068] In the nanoimprint process of S12, the fine uneven shape of the grid structure material 23 is transferred to the surface of the grid structure material 23 using a master plate 60 on which an inverted shape of the fine uneven shape of the grid structure 20 is formed (S12). As a result, an uneven pattern consisting of the base portion 21, the raised portion 22, and the recessed portion 24 is formed on the grid structure material 23. Furthermore, in the nanoimprint process, along with the transfer of the uneven pattern, the grid structure material 23 is cured by irradiating it with energy rays to form the grid structure 20 (S14). For example, if the grid structure material 23 is made of an ultraviolet-curable resin, the ultraviolet-curable resin on which the uneven pattern has been transferred may be cured by irradiating the grid structure material 23 with ultraviolet light using an ultraviolet irradiation device 66.

[0069] In steps S12 and S14 described above, the raised ridges 22 of the grid structure 20 are formed, having a tapered shape that narrows in width as it moves away from the base portion 21. The raised ridges 22 in the example of Figure 3 are trapezoidal (tapered), but they may be any other tapered shape.

[0070] Thus, in this embodiment, since the tapered ridge portion 22 is imprinted in the nanoimprint process S12, the master plate 60 can be easily peeled off from the grid structure material 23, resulting in excellent mold release properties. Furthermore, the ridge portion 22 of the grid structure 20 can be accurately molded into the desired shape without deformation.

[0071] Reflective film formation step (S16) Next, in S16, a reflective film 30 is formed using a metallic material such as Al or Ag to cover a part of the raised ridge portion 22 of the grid structure 20. The reflective film 30 is an example of a functional film that imparts a predetermined function to the polarizing element 1. The reflective film 30 is a thin metallic film (metal wire grid) for reflecting incident light that is incident on the grid structure 20 of the polarizing element 1.

[0072] In this reflective film forming step S16, the reflective film 30 is formed as follows: The reflective film 30 is formed so that it covers the tip 22a and the upper side of at least one side 22b of the protruding portion 22, but does not cover the lower sides of both side 22b of the protruding portion 22 or the base portion 21. Furthermore, the reflective film 30 is formed so that the surface of the reflective film 30 covering the protruding portion 22 is rounded and bulges in the width direction of the protruding portion 22. In addition, the maximum width W of the reflective film 30 covering the protruding portion 22 is also formed. ＭＡＸ (Maximum grid width W) ＭＡＸ ) However, the width W of the bottom of the aforementioned protruding section Ｂ (Grid bottom width W) Ｂ A reflective film 30 is formed so that the value is greater than or equal to the value shown.

[0073] For example, sputtering or vapor deposition can be used to form such a reflective film 30. The reflective film 30 is formed by sputtering or vapor deposition of a metal material alternately from an oblique direction onto the raised ridges 22 of the grid structure 20. This makes it possible to suitably form a reflective film 30 of a desired shape so as to roundly cover the tops of the raised ridges 22.

[0074] By forming the reflective film 30 in this manner, the convex portions 22 of the grid structure 20 and the reflective film 30 come to have the special tree shape described above. As a result, as mentioned above, even when light is incident on the polarizing element 1 at a relatively large and wide range of incident angles θ (for example, 30 to 60°) from an oblique direction, the transmission axis transmittance Tp of the P-polarized light contained in the obliquely incident light can be maintained at a high value, and the transmittance of P-polarized light (transmitted light) can be ensured. Therefore, since the value of Tp × Rs can be maintained at a high value (for example, 70% or more), the polarization separation characteristics of the polarizing element 1 for obliquely incident light can be improved.

[0075] The method for manufacturing the polarizing element 1 according to this embodiment has been described above. By following the above-described process, a polarizing element 1 with excellent polarization characteristics and heat dissipation can be manufactured without increasing the manufacturing cost or complexity of the polarizing element 1.

[0076] <4. Photocurable acrylic resin for imprinting> Next, the photocurable acrylic resin for imprinting according to this embodiment will be described. The photocurable acrylic resin for imprinting according to this embodiment contains a photopolymerization component.

[0077] <4.1. Composition of Photopolymerization Components> The composition of the photopolymerization components of the photocurable acrylic resin for imprinting according to this embodiment will be described below. The photopolymerization components according to this embodiment include at least resin (A) and resin (B). In addition, the photopolymerization components according to this embodiment may include resin (C) in addition to resin (A) and resin (B). Furthermore, the photopolymerization components according to this embodiment may consist only of resin (A) and resin (B), or only of resin (A), resin (B), and resin (C). Resins (A) to resin (C) will be described below.

[0078] Resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and / or a benzyl group. Resin (A) is, for example, one or both of phenylethyl acrylate and / or benzyl acrylate.

[0079] Resin (A) has a viscosity of, for example, 2.0 mPa·s or more and 10.0 mPa·s or less at 25°C. If resin (A) is phenylethyl acrylate, resin (A) has a viscosity of 9.0 mPa·s at 25°C. If resin (A) is benzyl acrylate, resin (A) has a viscosity of 2.2 mPa·s at 25°C. The viscosity is the viscosity of the liquid measured using a rotational viscometer and a vibration viscometer in accordance with JIS Z8803. The viscosity is measured using a cone plate with, for example, a Brookfield viscometer manufactured by Eiko Seiki Co., Ltd.

[0080] Resin (B) is a bifunctional compound. Resin (B) is, for example, a bifunctional acrylate monomer. Resin (B) is, for example, one or more selected from the group consisting of (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate, bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene, and 1,6-hexanediol diacrylate. It is preferable that Resin (B) contains 1,6-hexanediol diacrylate and one of (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate and bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene.

[0081] (Octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate is a bifunctional acrylate monomer represented by the following chemical formula (I). As (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate, for example, the product name "KAYARAD R-684" manufactured by Nippon Kayaku Co., Ltd. can be used. /

[0082] (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid is a bifunctional acrylate monomer represented by the following chemical formula (II). For example, the product name "KAYARAD R-604" manufactured by Nippon Kayaku Co., Ltd. can be used. /

[0083] 1,6-Hexanediol diacrylate is a bifunctional acrylate monomer represented by the following chemical formula (III). For example, 1,6-Hexanediol diacrylate can be used as the product name "A-HD-N" manufactured by Shin-Nakamura Chemical Industry Co., Ltd. CH ２ =CHCOO(CH ２ ) ６ OOCCH=CH ２ …(III)

[0084] Resin (B) has a viscosity of 5.0 mPa·s or more and 500 mPa·s or less at 25°C. If resin (B) is (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate, resin (B) has a viscosity of 100 mPa·s or more and 250 mPa·s or less at 25°C. If resin (B) is bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene, resin (B) has a viscosity of 200 mPa·s or more and 400 mPa·s or less at 25°C. If resin (B) is 1,6-hexanediol diacrylate, resin (B) has a viscosity of 6.5 mPa·s at 25°C.

[0085] Resin (C) is, for example, an acrylate monomer having three or more functional groups. Resin (C) includes, for example, one or both of dipentaerythritol hexaacrylate and tris-(2-acryloxyethyl) isocyanurate. For dipentaerythritol hexaacrylate, for example, product name "KAYARAD DPHA" manufactured by Nippon Kayaku Co., Ltd. can be used. For tris-(2-acryloxyethyl) isocyanurate, for example, product name "A-9300S" manufactured by Shin Nakamura Chemical Industry Co., Ltd. can be used.

[0086] Resin (C) has a viscosity of, for example, 1,000 mPa·s or more and 12,000 mPa·s or less at 25°C. If resin (C) is dipentaerythritol hexaacrylate, resin (C) has a viscosity of 5,000 mPa·s or more and 10,000 mPa·s or less at 25°C. If resin (C) is tris-(2-acryloxyethyl) isocyanurate, resin (C) has a viscosity of 1,000 mPa·s at 50°C.

[0087] <4.2. Content of each resin in the total photopolymerization component> Next, the content of each resin in the total photopolymerization component according to this embodiment will be described. In this embodiment, the content of resin (A) in the total photopolymerization component is 20% by mass or more, preferably 23% by mass or more. The content of resin (A) in the total photopolymerization component is 42% by mass or less, preferably 35% by mass or less, and more preferably 30% by mass or less. The content of resin (A) in the total photopolymerization component is 20% by mass or more and 42% by mass or less, preferably 20% by mass or more and 35% by mass or less, and more preferably 20% by mass or more and 30% by mass or less.

[0088] Furthermore, in this embodiment, the content of resin (B) relative to the total photopolymerization component is 43% by mass or more, preferably 45% by mass or more. The content of resin (B) relative to the total photopolymerization component is 66% by mass or less, preferably 60% by mass or less. The content of resin (B) relative to the total photopolymerization component is 43% by mass or more and 66% by mass or less, preferably 45% by mass or more and 66% by mass or less, and more preferably 45% by mass or more and 60% by mass or less.

[0089] Furthermore, in this embodiment, the content of resin (C) relative to the total photopolymerization component is, for example, 1% by mass or more, preferably 10% by mass or more, and more preferably 15% by mass or more. The content of resin (C) relative to the total photopolymerization component is, for example, 30% by mass or less, preferably 20% by mass or less. The content of resin (C) relative to the total photopolymerization component is, for example, 1% by mass or more and 30% by mass or less, preferably 10% by mass or more and 20% by mass or less.

[0090] Furthermore, in this embodiment, the total content of resin (A) and resin (B) relative to the total photopolymerization component is, for example, 70% by mass or more, preferably 80% by mass or more, and more preferably 85% by mass. The total content of resin (A) and resin (B) relative to the total photopolymerization component is, for example, 99% by mass or less, preferably 90% by mass or less. The total content of resin (A) and resin (B) relative to the total photopolymerization component is, for example, 70% by mass or more and 99% by mass or less, preferably 80% by mass or more and 90% by mass or less.

[0091] Furthermore, in this embodiment, the total content of resin (A) and resin (C) relative to the total photopolymerization component is, for example, 34% by mass or more, preferably 40% by mass or more. The total content of resin (A) and resin (C) relative to the total photopolymerization component is, for example, 57% by mass or less, preferably 54% by mass or less. The total content of resin (A) and resin (C) relative to the total photopolymerization component is, for example, 34% by mass or more and 57% by mass or less, preferably 40% by mass or more and 54% by mass or less.

[0092] Furthermore, in this embodiment, the total content of resin (B) and resin (C) relative to the total photopolymerization component is, for example, 58% by mass or more, preferably 67% by mass or more, and more preferably 70% by mass or more. The total content of resin (B) and resin (C) relative to the total photopolymerization component is, for example, 80% by mass or less, preferably 77% by mass or less. The total content of resin (B) and resin (C) relative to the total photopolymerization component is, for example, 58% by mass or more and 80% by mass or less, preferably 67% by mass or more and 77% by mass or less.

[0093] Furthermore, in this embodiment, the content of the resin having a viscosity of 20 mPa·s or less at 25°C relative to the total photopolymerization component is, for example, 43% by mass or more, preferably 46% by mass or more, and more preferably 50% by mass or more. The content of the resin having a viscosity of 20 mPa·s or less at 25°C relative to the total photopolymerization component is, for example, 84% by mass or less, preferably 66% by mass or less, and more preferably 60% by mass or less. The content of the resin having a viscosity of 20 mPa·s or less at 25°C relative to the total photopolymerization component is 43% by mass or more and 84% by mass or less, preferably 46% by mass or more and 66% by mass or less, and more preferably 50% by mass or more and 60% by mass or less.

[0094] <4.3. Photopolymerization Initiator> Next, the photopolymerization initiator according to this embodiment will be described. The photopolymerization initiator according to this embodiment is, for example, an acylphosphine oxide-based photopolymerization initiator or an alkylphenone-based photopolymerization initiator. As the photopolymerization initiator, for example, the product name "Irgacure 819" manufactured by IGM Resins B.V. can be used.

[0095] In photocurable acrylic resin for imprinting, when the total content of the photopolymerization components is 100% by mass, the content of the photopolymerization initiator is preferably 0.5% by mass or more, and more preferably 1% by mass or more. In photocurable acrylic resin for imprinting, when the total content of the photopolymerization components is 100% by mass, the content of the photopolymerization initiator is preferably 3% by mass or less. In photocurable acrylic resin for imprinting, when the total content of the photopolymerization components is 100% by mass, the content of the photopolymerization initiator is preferably 0.5% by mass or more and 3% by mass or less, and more preferably 1% by mass or more and 3% by mass or less.

[0096] <4.4. Viscosity of the photocurable acrylic resin for imprinting> Next, the viscosity of the photocurable acrylic resin for imprinting according to this embodiment will be described. Due to the relationship of the content ratios of resin (A), resin (B), and resin (C) shown in 4.2 above, the viscosity of the photocurable acrylic resin for imprinting at 25°C is, for example, 90 mPa·s or less, preferably 70 mPa·s or less, and more preferably 30 Pa·s or less. The viscosity of the photocurable acrylic resin for imprinting at 25°C is, for example, 10 mPa·s or more. The viscosity of the photocurable acrylic resin for imprinting at 25°C is, for example, 10 mPa·s or more and 90 mPa·s or less, preferably 10 mPa·s or more and 70 mPa·s or less, and more preferably 10 mPa·s or more and 30 Pa·s or less.

[0097] <4.5. YI Value of Cured Product of Photocurable Acrylic Resin for Imprinting> Next, the YI (Yellow Index) value of the cured product obtained by irradiating the photocurable acrylic resin for imprinting according to this embodiment with light (for example, ultraviolet light) will be described. The YI value is calculated based on JIS K 7373:2006 "Plastics - Determination of yellowness index and change of yellowness index". The YI value is calculated, for example, from the measurement results using the "UV-Vis-Near-Infrared Spectrophotometer V-770" manufactured by JASCO Corporation. Specifically, the UV-Vis-Near-Infrared Spectrophotometer V-770 uses a D65 light source and measures the transmittance of the cured product to light in the wavelength range of 380 nm to 800 nm at 0° incidence. Then, hue calculation is performed on the measurement results by software, and the X, Y, and Z values ​​of the XYZ color system are calculated. The YI value is calculated by substituting the calculated X, Y, and Z values ​​of the XYZ color system into the following formula (3) shown in JIS K 7373:2006: YI = 100 × (1.2985X - 1.1335Z) / Y …(3)

[0098] In the present embodiment, after holding the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the YI value of the cured product is preferably 0 or greater. After holding the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the YI value of the cured product may be 3.0 or less, preferably 2.5 or less, more preferably 2.0 or less, and even more preferably 1.4 or less. After holding the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the YI value of the cured product may be 0.0 or greater and 3.0 or less, preferably 0.0 or greater and 2.5 or less, more preferably 0.0 or greater and 2.0 or less, and even more preferably 0.0 or greater and 1.4 or less.

[0099] <4.6. Average Transmittance of Cured Photocurable Acrylic Resin for Imprinting> Next, the average transmittance to light of the cured photocurable acrylic resin for imprinting according to this embodiment will be described. The average transmittance is calculated by measuring the transmittance at 1 nm intervals in the wavelength range of 430 nm to 680 nm and taking a simple average of the 251 measurement data obtained. The transmittance is measured, for example, using a "UV-Vis-Near-Infrared Spectrophotometer V-770" manufactured by JASCO Corporation.

[0100] After holding the cured product of the photocurable acrylic resin for imprinting according to this embodiment at 150°C for 500 hours, the average transmittance of the cured product to light in the wavelength region of 430 nm to 680 nm may be 91% or more, preferably 91.5% or more, and more preferably 92% or more. After holding the cured product of the photocurable acrylic resin for imprinting according to this embodiment at 150°C for 500 hours, the average transmittance of the cured product to light in the wavelength region of 430 nm to 680 nm may be 93% or less. After holding the cured product of the photocurable acrylic resin for imprinting according to this embodiment at 150°C for 500 hours, the average transmittance of the cured product to light in the wavelength region of 430 nm to 680 nm may be 91% or more and 93% or less, preferably 91.5% or more and 93% or less, and more preferably 92% or more and 93% or less.

[0101] Furthermore, the difference in average transmittance of the cured product of the photocurable acrylic resin for imprinting according to this embodiment for light in the wavelength range of 430 nm to 680 nm before and after holding it at 150°C for 500 hours (|average transmittance before holding - average transmittance after holding|) may be -0.2% or more. The difference in average transmittance of the cured product of the photocurable acrylic resin for imprinting according to this embodiment for light in the wavelength range of 430 nm to 680 nm before and after holding it at 150°C for 500 hours (|average transmittance before holding - average transmittance after holding|) may be 0.6% or less, preferably 0.5% or less, and more preferably 0.2% or less. The difference in average transmittance of a cured photocurable acrylic resin for imprinting to light in the wavelength range of 430 nm to 680 nm before and after holding the cured product at 150°C for 500 hours (|average transmittance before holding - average transmittance after holding|) may be -0.2% or more and 0.6% or less, preferably -0.2% or more and 0.5% or less, and more preferably -0.2% or more and 0.2% or less.

[0102] After holding the cured product of the photocurable acrylic resin for imprinting according to this embodiment at 150°C for 500 hours, the average transmittance of the cured product to light in the wavelength range of 430 nm to 510 nm may be 90% or more, preferably 91% or more. After holding the cured product of the photocurable acrylic resin for imprinting according to this embodiment at 150°C for 500 hours, the average transmittance of the cured product to light in the wavelength range of 430 nm to 510 nm may be 92% or less. After holding the cured product of the photocurable acrylic resin for imprinting according to 150°C for 500 hours, the average transmittance of the cured product to light in the wavelength range of 430 nm to 510 nm may be 90% or more and 92% or less, preferably 91% or more and 92% or less.

[0103] Furthermore, the difference in average transmittance of the cured imprint photocurable acrylic resin to light in the wavelength range of 430 nm to 510 nm before and after holding the cured product at 150°C for 500 hours (|average transmittance before holding - average transmittance after holding|) may be 0.0% or more. The difference in average transmittance of the cured imprint photocurable acrylic resin to light in the wavelength range of 430 nm to 510 nm before and after holding the cured product at 150°C for 500 hours (|average transmittance before holding - average transmittance after holding|) may be 1.6% or less, preferably 1.1% or less, and more preferably 0.5% or less. The difference in average transmittance of a photocurable acrylic resin for imprinting to light in the wavelength range of 430 nm to 510 nm before and after holding the cured product at 150°C for 500 hours (|average transmittance before holding - average transmittance after holding|) may be 0.0% or more and 1.6% or less, preferably 0.0% or more and 1.1% or less, and more preferably 0.0% or more and 0.5% or less.

[0104] <4.7. Storage Modulus of Cured Photocurable Acrylic Resin for Imprinting> Next, we will explain the storage modulus of cured photocurable acrylic resin for imprinting. The storage modulus is the component of energy generated by external force and strain that is stored inside the object. In other words, the storage modulus indicates the hardness of the cured material. The larger the storage modulus, the harder the cured material. The storage modulus can be measured using, for example, a product named "DMA7100" manufactured by Hitachi High-Tech Corporation. For example, a sheet of cured material can be cut into 20 mm x 3 mm sections, and in tensile mode, the temperature can be increased at a constant frequency (1 Hz) and 5°C / min to measure the storage modulus at 25°C to 300°C.

[0105] At 30°C, the storage modulus of the cured product of the photocurable acrylic resin for imprinting according to this embodiment is 2.0 × 10⁻⁶. ９ It may be Pa or higher, preferably 2.5 × 10 ９ Pa or higher, more preferably 3.0 × 10 ９It is Pa or higher. The storage modulus of the cured product of the photocurable acrylic resin for imprinting at 30°C is 3.2 × 10⁻⁶. ９ It may be Pa or less. The storage modulus of the cured product of the photocurable acrylic resin for imprinting at 30°C is 2.0 × 10⁻⁶. ９ Pa or more, 3.2×10 ９ It may be less than or equal to Pa, preferably 2.5 × 10 ９ Pa or more, 3.2×10 ９ Pa or less, more preferably 3.0 × 10 ９ Pa or more, 3.2×10 ９ It is less than or equal to Pa.

[0106] At 110°C, the storage modulus of the cured product of the photocurable acrylic resin for imprinting according to this embodiment is 1.3 × 10⁻⁶. ８ It may be Pa or higher, preferably 1.5 × 10 ８ Pa or higher, more preferably 3.0 × 10 ８ Pa or higher, and more preferably 5.0 × 10 ８ It is Pa or higher. The storage modulus of the cured product of the photocurable acrylic resin for imprinting according to this embodiment at 110°C is 1.1 × 10⁻⁶. ９ It may be Pa or less. The storage modulus of the cured product of the photocurable acrylic resin for imprinting according to this embodiment at 110°C is 1.3 × 10⁻⁶ ８ Pa or more, 1.1×10 ９ It may be less than or equal to Pa, preferably 1.5 × 10 ８ Pa or more, 1.1×10 ９ Pa or less, more preferably 3.0 × 10 ８ Pa or more, 1.1×10 ９ Pa or less, and more preferably 5.0 × 10 ８ Pa or more, 1.1×10 ９ It is less than or equal to Pa.

[0107] At 120°C, the storage modulus of the cured product of the photocurable acrylic resin for imprinting according to this embodiment is 1.3 × 10⁻⁶. ８ It may be Pa or higher, preferably 3.0 × 10 ８Pa or higher, and more preferably 5.0 × 10 ８ It is Pa or higher. The storage modulus of the cured product of the photocurable acrylic resin for imprinting at 120°C is 9.1 × 10⁻⁶. ８ It may be Pa or less. The storage modulus of the cured product of the photocurable acrylic resin for imprinting at 120°C is 1.3 × 10⁻⁶. ８ Pa or more, 9.1×10 ８ It may be less than or equal to Pa, preferably 3.0 × 10 ８ Pa or more, 9.1×10 ８ Pa or less, and more preferably 5.0 × 10 ８ Pa or more, 9.1×10 ８ It is less than or equal to Pa.

[0108] At 130°C, the storage modulus of the cured product of the photocurable acrylic resin for imprinting according to this embodiment is 1.4 × 10⁻⁶. ８ It may be Pa or higher, preferably 2.0 × 10 ８ Pa or higher, and more preferably 7.0 × 10 ８ It is Pa or higher. The storage modulus of the cured product of the photocurable acrylic resin for imprinting at 130°C is 8.0 × 10⁻⁶. ８ It may be Pa or less. The storage modulus of the cured product of the photocurable acrylic resin for imprinting at 130°C is 1.4 × 10⁻⁶ ８ Pa or more, 8.0×10 ８ It may be less than or equal to Pa, preferably 2.0 × 10 ８ Pa or more, 8.0×10 ８ Pa or less, and more preferably 7.0 × 10 ８ Pa or more, 8.0×10 ８ It is less than or equal to Pa.

[0109] <4.8. Glass transition temperature Tg of cured photocurable acrylic resin for imprinting> Next, the glass transition temperature Tg of cured photocurable acrylic resin for imprinting will be explained. The glass transition temperature Tg can be measured using, for example, a product named "DMA7100" manufactured by Hitachi High-Tech Corporation. For example, a sheet of the cured material is cut to 20 mm in length and 3 mm in width, and the temperature is increased at a constant frequency (1 Hz) in tensile mode at 5°C / min, and the maximum value of the loss tangent tanδ is confirmed between 25°C and 300°C.

[0110] The glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting according to this embodiment may be 58°C or higher, preferably 80°C or higher, and more preferably 100°C or higher. The glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting may be 181°C or lower, preferably 110°C or lower. The glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting may be 58°C or higher and 110°C or lower, preferably 80°C or higher and 110°C or lower, and more preferably 100°C or higher and 110°C or lower.

[0111] <4.9. Method for Manufacturing Photocurable Acrylic Resin for Imprinting> Next, a method for manufacturing photocurable acrylic resin for imprinting according to this embodiment will be described.

[0112] In the method for producing the photocurable acrylic resin for imprinting according to this embodiment, it is preferable to mix multiple types of resins contained in the photopolymerization component, and then mix a powdered photopolymerization initiator into the mixed resin of the multiple types of resins. For example, if the photopolymerization component contains resin (A) and resin (B), the method for producing the photocurable acrylic resin for imprinting includes mixing resin (A) and resin (B), and mixing a photopolymerization initiator into the mixed resin of resin (A) and resin (B). Also, if the photopolymerization component contains resin (A), resin (B), and resin (C), the method for producing the photocurable acrylic resin for imprinting includes mixing resin (A), resin (B), and resin (C), and mixing a photopolymerization initiator into the mixed resin of resin (A), resin (B), and resin (C).

[0113] Furthermore, when the photopolymerization component contains multiple types of resins, the method for producing a photocurable acrylic resin for imprinting preferably involves mixing the resins in order from the resin with the lowest viscosity among the multiple types of resins contained in the photopolymerization component to produce a mixed resin. For example, when the photopolymerization component contains resin (A), resin (B), and resin (C), the method for producing a photocurable acrylic resin for imprinting includes producing a first mixed resin by mixing resin (A) and resin (B), and producing a second mixed resin by mixing resin (C) into the first mixed resin. It is also preferable to mix a photopolymerization initiator into the second mixed resin.

[0114] Furthermore, a suitable method for manufacturing photocurable acrylic resin for imprinting is to use, for example, a rotating / revolving mixer.

[0115] <4.10. Effects of the photocurable acrylic resin for imprinting> As described above, the photocurable acrylic resin for imprinting according to this embodiment is a photocurable acrylic resin for imprinting that contains a photopolymerization component, wherein the photopolymerization component comprises resin (A) and resin (B), where resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, and resin (B) is a bifunctional compound, the content of resin (A) relative to the total photopolymerization component is 20% by mass or more and 42% by mass or less, and the content of resin (B) relative to the total photopolymerization component is 43% by mass or more and 66% by mass or less.

[0116] As described above, the photocurable acrylic resin for imprinting according to this embodiment includes resin (A). Resin (A) has one or both of phenyl groups and benzyl groups. Therefore, resin (A) has low steric hindrance and high reactivity. Consequently, in the photocurable acrylic resin for imprinting according to this embodiment, even when the cured product of the photocurable acrylic resin for imprinting is heated, the decomposition of the cured product can be suppressed by the interaction of the aromatic rings at the ends. Therefore, the photocurable acrylic resin for imprinting according to this embodiment can improve the heat resistance of the cured product of the photocurable acrylic resin for imprinting.

[0117] Furthermore, resin (A) is a monofunctional acrylate monomer. Therefore, resin (A) can terminate the reaction at the polymer ends during the polymerization reaction (curing reaction) of the photocurable acrylic resin for imprinting. Consequently, it is possible to suppress degradation from the end groups of the cured product (polymer) of the photocurable acrylic resin for imprinting.

[0118] Furthermore, the photocurable acrylic resin for imprinting according to this embodiment includes resin (B). This allows the photocurable acrylic resin for imprinting according to this embodiment to improve the heat resistance of the cured product of the photocurable acrylic resin for imprinting.

[0119] Furthermore, as described above, in the photocurable acrylic resin for imprinting according to this embodiment, the content of resin (A) relative to the total photopolymerization components is 20% by mass or more and 42% by mass or less, and the content of resin (B) relative to the total photopolymerization components is 43% by mass or more and 66% by mass or less. As a result, the photocurable acrylic resin for imprinting according to this embodiment can achieve both low viscosity and improved heat resistance of the cured product.

[0120] Because the photocurable acrylic resin for imprinting according to this embodiment has low viscosity, in the nanoimprinting step S12 (Figure 3), the thickness of the photocurable acrylic resin layer when the master plate 60 is pressed against the photocurable acrylic resin for imprinting can be made uniform. This makes it possible to make the peeling force applied when peeling the master plate 60 from the cured photocurable acrylic resin layer uniform across the surface. Therefore, it is possible to avoid the situation in which the cured photocurable acrylic resin layer peels off from the substrate 10. As a result, the residue of the cured photocurable acrylic resin layer on the master plate 60 can be suppressed, and the master plate 60 can be reused repeatedly. Furthermore, because the peeling force can be made uniform across the surface, it is possible to avoid the deformation of the fine uneven shape transferred to the cured photocurable acrylic resin layer when peeling off the master plate 60. As a result, it is possible to suppress the deterioration of optical properties caused by the fine uneven shape of the cured photocurable acrylic resin. Therefore, as described above, when the grid structure 20 is manufactured using, for example, a cured product of a photocurable acrylic resin for imprinting, it is possible to suppress the decrease in the polarization properties of the grid structure 20.

[0121] Furthermore, because the photocurable acrylic resin for imprinting according to this embodiment has low viscosity, the ability of the photocurable acrylic resin to conform to the fine uneven shape of the master plate 60 when the master plate 60 is pressed against the photocurable acrylic resin for imprinting in the nanoimprinting step S12 can be improved. Therefore, in the nanoimprinting step S12, it becomes possible to evenly transfer the fine uneven shape of the master plate 60 to the layer of photocurable acrylic resin for imprinting.

[0122] Furthermore, because the photocurable acrylic resin for imprinting according to this embodiment has low viscosity, the incorporation of air bubbles into the photocurable acrylic resin for imprinting can be suppressed in the nanoimprinting process S12. This makes it possible to avoid situations in which a part of the fine uneven shape is interrupted by air bubbles in the cured product of the photocurable acrylic resin for imprinting. Therefore, as described above, for example, when a grid structure 20 is manufactured using the cured product of the photocurable acrylic resin for imprinting, the breakage of the convex portions 22 of the grid structure 20 can be suppressed.

[0123] The cured product of the photocurable acrylic resin for imprinting according to this embodiment has superior heat resistance. Therefore, when an optical material (for example, the grid structure 20 of the wire grid polarizing element 1) is manufactured using the cured product of the photocurable acrylic resin for imprinting, the deterioration of the optical properties of the optical material can be further suppressed even if the optical material is subjected to further heat treatment such as vapor deposition.

[0124] Furthermore, as described above, the photopolymerization component may further contain resin (C), where resin (C) is an acrylate monomer having three or more functional groups, and the content of resin (C) relative to the total photopolymerization component may be 1% by mass or more and 30% by mass or less.

[0125] As a result, the photocurable acrylic resin for imprinting according to this embodiment can increase the crosslinking density during curing, and can suppress the decrease in the storage modulus of the cured product of the photocurable acrylic resin for imprinting at high temperatures. Furthermore, as described above, in the photocurable acrylic resin for imprinting according to this embodiment, the content of resin (C) with respect to the total photopolymerization component is preferably 1% by mass or more and 30% by mass or less. As a result, the decrease in the storage modulus of the cured product of the photocurable acrylic resin for imprinting at high temperatures can be further suppressed.

[0126] Furthermore, as described above, resin (A) may be one or both of phenylethyl acrylate and benzyl acrylate.

[0127] As a result, the photocurable acrylic resin for imprinting according to this embodiment can have improved heat resistance of the cured product. In this case, resin (A) has a viscosity of 9.0 mPa·s or less at 25°C. Therefore, the viscosity of the photocurable acrylic resin for imprinting according to this embodiment can be further reduced.

[0128] Furthermore, as described above, resin (B) may be one or more selected from the group consisting of (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate, bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene, and 1,6-hexanediol diacrylate.

[0129] As a result, the photocurable acrylic resin for imprinting according to this embodiment can further improve the heat resistance of the cured product of the photocurable acrylic resin for imprinting.

[0130] Furthermore, as described above, resin (B) may also contain one of the following: 1,6-hexanediol diacrylate, (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate, and bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene.

[0131] This makes it possible to lower the viscosity of the photocurable acrylic resin for imprinting and to further improve its heat resistance.

[0132] Furthermore, as described above, resin (C) may contain one or both of dipentaerythritol hexaacrylate and tris-(2-acryloxyethyl) isocyanurate.

[0133] This further suppresses the decrease in the storage modulus of the cured product of the photocurable acrylic resin for imprinting at high temperatures.

[0134] Furthermore, as mentioned above, the viscosity of the photocurable acrylic resin for imprinting at 25°C may be 90 mPa·s or less.

[0135] As a result, in the nanoimprint process S12 described above, the thickness of the layer of photocurable acrylic resin for imprinting when the master plate 60 is pressed against the photocurable acrylic resin for imprinting can be made more uniform, the conformability of the photocurable acrylic resin for imprinting to the fine uneven shape of the master plate 60 can be further improved, and the incorporation of air bubbles into the photocurable acrylic resin for imprinting can be further suppressed.

[0136] Furthermore, as described above, in the photocurable acrylic resin for imprinting according to this embodiment, by setting the content of resin (A) to 20% by mass or more and 42% by mass or less, and the content of resin (B) to 43% by mass or more and 66% by mass or less, the viscosity of the photocurable acrylic resin for imprinting at 25°C can be set to 90 mPa·s or less.

[0137] For example, the cured product of the photocurable acrylic resin for imprinting according to this embodiment has excellent heat resistance, and after holding the cured product at 150°C for 500 hours, the YI value of the cured product is 3 or less. Therefore, by manufacturing an optical material with the cured product of the photocurable acrylic resin for imprinting, yellowing of the optical material can be suppressed and transparency can be maintained even when the optical material is subjected to further heat treatment such as vapor deposition.

[0138] Furthermore, as mentioned above, the storage modulus of the cured product of the photocurable acrylic resin for imprinting at 30°C is 2.0 × 10⁻⁶. ９ It may also be assumed to be Pa or greater.

[0139] This makes it possible to better avoid the deformation of the fine uneven shape transferred to the layer of hardened photocurable acrylic resin for imprinting when peeling off the master plate 60 in the nanoimprinting process S12 (Figure 3). Therefore, it is possible to further suppress the deterioration of optical properties caused by the fine uneven shape of the cured photocurable acrylic resin for imprinting. Accordingly, as described above, for example, when a grid structure 20 is manufactured using a cured photocurable acrylic resin for imprinting, it is possible to further suppress the deterioration of the polarization properties of the grid structure 20.

[0140] Furthermore, for example, the cured product of the photocurable acrylic resin for imprinting according to this embodiment has excellent heat resistance, and the storage modulus of the cured product at 120°C is 1.3 × 10⁻⁶. ８ The pressure may be Pa or higher. Therefore, by manufacturing an optical material from a cured product of imprint-compatible photocurable acrylic resin, deformation of the optical material can be further suppressed even when the optical material is subjected to further heat treatment such as vapor deposition. As a result, the deterioration of the optical properties of the optical material can be further suppressed.

[0141] Furthermore, for example, the cured product of the photocurable acrylic resin for imprinting according to this embodiment has superior heat resistance, and the storage modulus of the cured product at 130°C is 1.4 × 10⁻⁶. ８ The pressure may be Pa or higher. Therefore, by manufacturing an optical material from a cured product of an imprint-compatible photocurable acrylic resin, deformation of the optical material can be more effectively suppressed even when the optical material is subjected to further heat treatment such as vapor deposition. This makes it possible to more effectively suppress the deterioration of the optical properties of the optical material.

[0142] Furthermore, for example, the cured product of the photocurable acrylic resin for imprinting according to this embodiment has superior heat resistance. After holding the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the average transmittance of the cured product to light in the wavelength range of 430 nm to 680 nm is 91% or more. Therefore, by manufacturing an optical material using the cured product of the photocurable acrylic resin for imprinting, even if the optical material is subjected to further heat treatment such as vapor deposition, the average transmittance of the optical material to light in the above wavelength range can be maintained at a higher level.

[0143] Furthermore, for example, the cured product of the photocurable acrylic resin for imprinting according to this embodiment has superior heat resistance. After holding the cured product of the photocurable acrylic resin for imprinting at 120°C for 500 hours, the average transmittance of the cured product to light in the wavelength range of 430 nm to 510 nm is 90% or more. Therefore, by manufacturing an optical material using the cured product of the photocurable acrylic resin for imprinting, even if the optical material is subjected to further heat treatment such as vapor deposition, the average transmittance of the optical material to light in the above wavelength range can be maintained at a higher level.

[0144] Furthermore, as described above, when manufacturing the wire grid polarizing element 1, a reflective film 30 is deposited onto the grid structure 20. The grid structure 20 is heated during the deposition of this reflective film 30. Here, if the heat resistance of the grid structure 20 is low, the grid structure 20 deforms during the deposition of the reflective film 30, which leads to a problem of reduced polarization characteristics.

[0145] However, the cured product of the photocurable acrylic resin for imprinting according to this embodiment has superior heat resistance. Therefore, by manufacturing the grid structure 20 with the cured product of the photocurable acrylic resin for imprinting, yellowing and deformation of the grid structure 20 can be further suppressed even when the reflective film 30 is deposited, and the average transmittance of the grid structure 20 for light in the wavelength range of 430 nm to 680 nm and light in the wavelength range of 430 nm to 510 nm can be maintained at a higher level. As a result, the decrease in the polarization characteristics of the grid structure 20 can be suppressed even more effectively.

[0146] Furthermore, as described above, in the photocurable acrylic resin for imprinting according to this embodiment, the content of resin (C) relative to the total photopolymerization component is preferably 1% by mass or more and 30% by mass or less. This further improves the heat resistance of the photocurable acrylic resin for imprinting according to this embodiment. For example, the storage modulus of the cured product of the photocurable acrylic resin for imprinting at 120°C is 1.3 × 10⁻⁶. ８ The pressure can be set to Pa or higher, and the storage modulus of the cured product of the photocurable acrylic resin for imprinting at 130°C is 1.4 × 10⁻⁶. ８ It can be set to Pa or higher.

[0147] Furthermore, as described above, in the method for producing a photocurable acrylic resin for imprinting according to this embodiment, which includes a photopolymerization component and a photopolymerization initiator for polymerizing the photopolymerization component, the photopolymerization component comprises resin (A) and resin (B), wherein resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, and resin (B) is a bifunctional compound, the content of resin (A) to the total photopolymerization component is 20% by mass or more and 42% by mass or less, and the content of resin (B) to the total photopolymerization component is 43% by mass or more and 66% by mass or less, and the method includes mixing resin (A) and resin (B), and mixing a photopolymerization initiator into the mixed resin of resin (A) and resin (B).

[0148] This allows for a suitable mixing of the photopolymerization component and the photopolymerization initiator. Therefore, the photopolymerization component can be cured evenly (without unevenness). As a result, it becomes possible to achieve uniform heat resistance of the cured product of the photocurable acrylic resin for imprinting.

[0149] Furthermore, as described above, in the method for producing a photocurable acrylic resin for imprinting containing a photopolymerization component according to this embodiment, the photopolymerization component comprises resin (A), resin (B), and resin (C), wherein resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, resin (B) is a bifunctional compound, and resin (C) is an acrylate monomer having three or more functional groups, the content of resin (A) relative to the total photopolymerization component is 20% by mass or more and 42% by mass or less, the content of resin (B) relative to the total photopolymerization component is 43% by mass or more and 66% by mass or less, and the content of resin (C) relative to the total photopolymerization component is 1% by mass or more and 30% by mass or less, and the method comprises producing a first mixed resin by mixing resin (A) and resin (B), and producing a second mixed resin by mixing resin (C) with the first mixed resin.

[0150] This allows for a suitable mixing of resin (A), resin (B), and resin (C). Consequently, it becomes possible to achieve uniform viscosity in the photocurable acrylic resin for imprinting. Furthermore, it becomes possible to further improve the uniformity of heat resistance of the cured product of the photocurable acrylic resin for imprinting.

[0151] <4.11. Other Components> The photocurable acrylic resin for imprinting may contain other components (additives) to the extent that they do not impair the effects described in 4.10 above. Other components include, for example, antioxidants, phosphors, plasticizers, ultraviolet absorbers, defoamers, thixotropes, polymerization inhibitors, mold release agents, metal oxide particles, etc.

[0152] <4.12. Application Examples of Photocurable Acrylic Resin for Imprinting> As described above, the photocurable acrylic resin for imprinting has low viscosity and excellent heat resistance of the cured product. For this reason, the photocurable acrylic resin for imprinting can be applied to the grid structure 20 of the wire grid polarizing element 1, as described above. Furthermore, the photocurable acrylic resin for imprinting can also be applied to moth-eye structures and the like that have an anti-reflective function for visible light.

[0153] Next, embodiments of the present invention will be described. However, the embodiments described below are specific examples provided to illustrate the structure and effects of the photocurable acrylic resin for imprinting according to the present embodiment described above, and the present invention is not limited to the embodiments described below.

[0154] Examples 51-58 and Comparative Examples 51-57 were prepared as photocurable acrylic resins for imprinting.

[0155] The viscosity of the photocurable acrylic resins for imprinting according to Examples 51-58 and Comparative Examples 51-57 was measured. The viscosity was measured using a cone plate with a Brookfield viscometer manufactured by Eiko Seiki Co., Ltd.

[0156] The YI values ​​of the cured imprint photocurable acrylic resins according to Examples 51-58 and Comparative Examples 51-57 were measured after being held at 150°C for 500 hours (heat treatment). The YI values ​​were calculated based on measurement results using a UV-Vis-Near-Infrared Spectrophotometer V-770 manufactured by JASCO Corporation. The measurement conditions and calculation method for the YI values ​​were the same as in the embodiments described above.

[0157] For the cured products of the photocurable acrylic resins for imprinting according to Examples 51-58 and Comparative Examples 51-57, the average transmittance of the cured products to light in the wavelength range of 430 nm to 680 nm and the average transmittance of the cured products to light in the wavelength range of 430 nm to 510 nm was measured before heat treatment (holding at 150°C for 500 hours). Furthermore, after holding the cured products of the photocurable acrylic resins for imprinting according to Examples 51-58 and Comparative Examples 51-57 at 150°C for 500 hours, the average transmittance of the cured products to light in the wavelength range of 430 nm to 680 nm and the average transmittance of the cured products to light in the wavelength range of 430 nm to 510 nm was measured. The average transmittance was calculated by measuring the transmittance at 1 nm intervals in the wavelength range of 430 nm to 680 nm and simply averaging the obtained 251 measurement data. The average transmittance was measured using the "UV-Vis-Near-Infrared Spectrophotometer V-770" manufactured by JASCO Corporation.

[0158] The storage modulus at 30°C, 110°C, 120°C, and 130°C was measured for the cured products of the photocurable acrylic resin for imprinting according to Examples 51-58 and Comparative Examples 51-57. The storage modulus was measured using a Hitachi High-Technologies Corporation product called "DMA7100". Sheets of the cured photocurable acrylic resin for imprinting according to Examples 51-58 and Comparative Examples 51-57 were cut into 20 mm x 3 mm sections, and the temperature was increased at a constant frequency (1 Hz) in tensile mode at 5°C / min to measure the storage modulus from 25°C to 300°C.

[0159] The glass transition temperature Tg of the cured products of the photocurable acrylic resin for imprinting according to Examples 51-58 and Comparative Examples 51-57 was measured. The glass transition temperature Tg was measured using a Hitachi High-Technologies Corporation product called "DMA7100". Sheets of the cured photocurable acrylic resin for imprinting according to Examples 51-58 and Comparative Examples 51-57 were cut into 20 mm x 3 mm sections, and the temperature was increased at a constant frequency (1 Hz) in tensile mode at 5°C / min. The maximum value of the loss tangent tanδ was confirmed between 25°C and 300°C.

[0160] The composition and viscosity of the photocurable acrylic resins for imprinting in Examples 51 to 54 are shown in Table 1 below. The YI value, average transmittance, storage modulus, and glass transition temperature Tg of the cured products of the photocurable acrylic resins for imprinting in Examples 51 to 54 are shown in Table 2 below.

[0161] The composition and viscosity of the photocurable acrylic resins for imprinting in Examples 55 to 58 are shown in Table 3 below. The YI value, average transmittance, storage modulus, and glass transition temperature Tg of the cured products of the photocurable acrylic resins for imprinting in Examples 55 to 58 are shown in Table 4 below.

[0162] The composition and viscosity of the photocurable acrylic resins for imprinting in Comparative Examples 51 to 54 are shown in Table 5 below. The YI value, average transmittance, storage modulus, and glass transition temperature Tg of the cured products of the photocurable acrylic resins for imprinting in Comparative Examples 51 to 54 are shown in Table 6 below.

[0163] The composition and viscosity of the photocurable acrylic resins for imprinting in Comparative Examples 55 to 57 are shown in Table 7 below. The YI value, average transmittance, storage modulus, and glass transition temperature Tg of the cured products of the photocurable acrylic resins for imprinting in Comparative Examples 55 to 57 are shown in Table 8 below.

[0164] Note that the units of the content percentages in Tables 1, 3, 5, and 7 are in mass percent. Also, the viscosity in Tables 1, 3, 5, and 7 is the viscosity at 25°C [mPa·s].

[0165]

[0166]

[0167] [Example 51] As shown in Table 1, Example 51 contains only resin (A), resin (B), and resin (C) as photopolymerization components, and further contains a photopolymerization initiator. Phenyl ethyl acrylate (PEA) was used as resin (A). The phenyl ethyl acrylate used was "Viscote #192HP" manufactured by Osaka Organic Chemical Industry Co., Ltd. As resin (B), (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid and 1,6-hexanediol diacrylate were used. The (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid used was "KAYARAD R-604" manufactured by Nippon Kayaku Co., Ltd. The 1,6-hexanediol diacrylate used was "A-HD-N" manufactured by Shin Nakamura Chemical Industry Co., Ltd. Dipentaerythritol hexaacrylate (DPHA) was used as resin (C). The dipentaerythritol hexaacrylate used was the product name "KAYARAD DPHA" manufactured by Nippon Kayaku Co., Ltd. The photopolymerization initiator used was the product name "Irgacure 819" manufactured by IGM Resins B. V. In Example 51, the content of resin (A) in the total photopolymerization components was 33% by mass, the content of resin (B) was 66% by mass, and the content of resin (C) was 1% by mass. In Example 51, the ratio of 1,6-hexanediol diacrylate to bisacrylic acid (2,2-dimethylethylene) (5-ethyl-1,3-dioxan-2,5-diyl)methylene in resin (B) was 1:1. In Example 51, the content of the photopolymerization initiator was set to 0.5% by mass when the total content of the photopolymerization components was set to 100% by mass.

[0168] As shown in Table 1, the viscosity of the photocurable acrylic resin for imprinting in Example 51 was 12.32 mPa·s.

[0169] As shown in Table 2, the YI value of the cured product of the photocurable acrylic resin for imprinting in Example 51 after heat treatment was 1.1. From these results, it was confirmed that a low YI value can be maintained even when the cured product of Example 51 is subjected to heat treatment at 150°C.

[0170] As shown in Table 2, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 51 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 91.9%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.7%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 51 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 92.1%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 91.6%.

[0171] In the cured product of Example 51, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was -0.2%. In the cured product of Example 51, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +0.1%. From these results, it was confirmed that even when the cured product of Example 51 is subjected to heat treatment at 150°C, the average transmittance for light in the wavelength range of 430 nm to 680 nm and the average transmittance for light in the wavelength range of 430 nm to 510 nm hardly decreases.

[0172] As shown in Table 2, the storage modulus at 30°C of the cured photocurable acrylic resin for imprinting in Example 51 is 2.0 × 10⁻⁶. ９ The storage modulus at 110°C for the cured photocurable acrylic resin for imprinting in Example 51 was 1.3 × 10⁻⁶. ８ The pressure was Pa. The storage modulus at 120°C of the cured photocurable acrylic resin for imprinting in Example 51 was 1.3 × 10⁻⁶. ８ The storage modulus at 130°C for the cured photocurable acrylic resin for imprinting in Example 51 was 1.4 × 10⁻⁶. ８ The result was Pa. From the above results, the cured product of Example 51 was 2.0 × 10 before heat treatment. ９It was confirmed that it possessed a high storage modulus of Pa. Furthermore, it was confirmed that the decrease in storage modulus was suppressed even when the cured product of Example 51 was subjected to a heat treatment at 150°C.

[0173] As shown in Table 2, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 51 was 70.7°C. From these results, it was confirmed that, despite the glass transition temperature Tg being less than 110°C, the cured product of Example 51 was able to keep the YI value low after heat treatment at 150°C, maintain a high average transmittance after heat treatment at 150°C, and further suppress the decrease in storage modulus after heat treatment at 150°C.

[0174] [Example 52] As shown in Table 1, Example 52 differs from Example 51 only in the content of resins (A) to (C). In Example 52, the content of resin (A) in the total photopolymerization components was 30% by mass, the content of resin (B) was 60% by mass, and the content of resin (C) was 10% by mass. In Example 52 as well, the ratio of 1,6-hexanediol diacrylate to (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid in resin (B) was 1:1.

[0175] As shown in Table 1, the viscosity of the photocurable acrylic resin for imprinting in Example 52 was 20.54 mPa·s. Furthermore, the photocurable acrylic resin for imprinting in Example 52 had a higher resin (C) content compared to the photocurable acrylic resin for imprinting in Example 51. It is presumed that this resulted in a higher viscosity for the photocurable acrylic resin for imprinting in Example 52 than for the photocurable acrylic resin for imprinting in Example 51.

[0176] As shown in Table 2, the YI value of the cured product of the photocurable acrylic resin for imprinting in Example 52 after heat treatment was 1.6. From these results, it was confirmed that the cured product of Example 52 can maintain a low YI value even after heat treatment at 150°C. Furthermore, the photocurable acrylic resin for imprinting in Example 52 has a higher resin (C) content compared to the photocurable acrylic resin for imprinting in Example 51. It is presumed that this is why the YI value of the cured product of the photocurable acrylic resin for imprinting in Example 52 is higher than that of the cured product of the photocurable acrylic resin for imprinting in Example 51.

[0177] As shown in Table 2, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 52 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 91.9%, and the average transmittance of the cured product for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.8%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 52 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 91.8%, and the average transmittance of the cured product for light in the wavelength range of 430 nm to 510 nm after heat treatment was 91.0%.

[0178] In the cured product of Example 52, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was +0.1%. In the cured product of Example 52, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +0.8%. From these results, it was confirmed that even when the cured product of Example 52 is subjected to heat treatment at 150°C, the average transmittance for light in the wavelength range of 430 nm to 680 nm and the average transmittance for light in the wavelength range of 430 nm to 510 nm hardly decreases. Furthermore, the photocurable acrylic resin for imprinting in Example 52 has a higher resin (C) content compared to the photocurable acrylic resin for imprinting in Example 51. As a result, it is presumed that the difference ΔA in average transmittance for the cured photocurable acrylic resin for imprinting in Example 52 for light in the wavelength range of 430 nm to 510 nm was slightly larger than the difference ΔA in average transmittance for the cured photocurable acrylic resin for imprinting in Example 51.

[0179] As shown in Table 2, the storage modulus at 30°C of the cured photocurable acrylic resin for imprinting in Example 52 is 3.1 × 10⁻⁶. ９ The storage modulus at 110°C for the cured photocurable acrylic resin for imprinting in Example 52 was 5.1 × 10⁻⁶. ８ The pressure was Pa. The storage modulus at 120°C of the cured product of the photocurable acrylic resin for imprinting in Example 52 was 3.9 × 10⁻⁶. ８ The storage modulus at 130°C for the cured photocurable acrylic resin for imprinting in Example 52 was 3.3 × 10⁻⁶. ８ The result was Pa. From the above results, the cured product of Example 52 was 3.1 × 10 before heat treatment. ９It was confirmed that it has a high storage modulus of Pa. Furthermore, it was confirmed that the decrease in storage modulus was suppressed even when the cured product of Example 52 was subjected to a heat treatment at 150°C. In addition, the photocurable acrylic resin for imprinting in Example 52 has a higher resin (C) content compared to the photocurable acrylic resin for imprinting in Example 51. As a result, it is presumed that the storage modulus of the cured product of the photocurable acrylic resin for imprinting in Example 52 is greater than that of the cured product of the photocurable acrylic resin for imprinting in Example 51.

[0180] As shown in Table 2, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 52 was 103.1°C. From these results, it was confirmed that, despite the glass transition temperature Tg being less than 110°C, the cured product of Example 52 was able to keep the YI value low after heat treatment at 150°C, maintain a high average transmittance after heat treatment at 150°C, and further suppress the decrease in storage modulus after heat treatment at 150°C.

[0181] [Example 53] As shown in Table 1, Example 53 differs from Examples 51 and 52 only in the content of resins (A) to (C). In Example 53, the content of resin (A) in the total photopolymerization components was 23.3% by mass, the content of resin (B) was 46.7% by mass, and the content of resin (C) was 30% by mass. In Example 53 as well, the ratio of 1,6-hexanediol diacrylate to bisacrylic acid (2,2-dimethylethylene) (5-ethyl-1,3-dioxan-2,5-diyl)methylene in resin (B) was 1:1.

[0182] As shown in Table 1, the viscosity of the photocurable acrylic resin for imprinting in Example 53 was 68.12 mPa·s. Furthermore, the photocurable acrylic resin for imprinting in Example 53 had a higher resin (C) content compared to the photocurable acrylic resin for imprinting in Example 52. It is presumed that this resulted in a higher viscosity for the photocurable acrylic resin for imprinting in Example 53 than for the photocurable acrylic resin for imprinting in Example 52.

[0183] As shown in Table 2, the YI value of the cured product of the photocurable acrylic resin for imprinting in Example 53 after heat treatment was 2.3. From these results, it was confirmed that the cured product of Example 53 can maintain a low YI value even after heat treatment at 150°C. Furthermore, the photocurable acrylic resin for imprinting in Example 53 has a higher resin (C) content compared to the photocurable acrylic resin for imprinting in Example 52. It is presumed that this is why the YI value of the cured product of the photocurable acrylic resin for imprinting in Example 53 is higher than that of the cured product of the photocurable acrylic resin for imprinting in Example 52.

[0184] As shown in Table 2, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 53 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 92.0%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.8%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 53 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 91.8%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 90.7%.

[0185] In the cured product of Example 53, the difference ΔA (average transmittance before heat treatment - average transmittance after heat treatment) in the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less before and after heat treatment was +0.2%. In the cured product of Example 53, the difference ΔA in the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less before and after heat treatment was +1.1%. From the above results, it was confirmed that even when the cured product of Example 53 was subjected to a heat treatment at 150 °C, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less, and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less hardly decreased. Also, in the imprint photo-curable acrylic resin of Example 53, the content of resin (C) is higher compared to the imprint photo-curable acrylic resin of Example 52. Thus, it is presumed that the difference ΔA in the average transmittance of the cured product of the imprint photo-curable acrylic resin of Example 53 became larger than the difference ΔA in the average transmittance of the cured product of the imprint photo-curable acrylic resin of Example 52.

[0186] As shown in Table 2, the storage modulus at 30 °C of the cured product of the imprint photo-curable acrylic resin of Example 53 was 3.2×10 ９ Pa. The storage modulus at 110 °C of the cured product of the imprint photo-curable acrylic resin of Example 53 was 1.1×10 ９ Pa. The storage modulus at 120 °C of the cured product of the imprint photo-curable acrylic resin of Example 53 was 9.1×10 ８ Pa. The storage modulus at 130 °C of the cured product of the imprint photo-curable acrylic resin of Example 53 was 8.0×10 ８ Pa. From the above results, the cured product of Example 53 had a storage modulus of 3.2×10 ９It was confirmed that it has a high storage modulus of Pa. Furthermore, it was confirmed that the decrease in storage modulus was suppressed even when the cured product of Example 53 was subjected to a heat treatment at 150°C. In addition, the photocurable acrylic resin for imprinting in Example 53 has a higher resin (C) content compared to the photocurable acrylic resin for imprinting in Example 52. As a result, it is presumed that the storage modulus of the cured product of the photocurable acrylic resin for imprinting in Example 53 is greater than that of the cured product of the photocurable acrylic resin for imprinting in Example 52.

[0187] As shown in Table 2, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 53 was 103.8°C. From these results, it was confirmed that, despite the glass transition temperature Tg being less than 110°C, the cured product of Example 53 was able to keep the YI value low after heat treatment at 150°C, maintain a high average transmittance after heat treatment at 150°C, and further suppress the decrease in storage modulus after heat treatment at 150°C.

[0188] [Example 54] As shown in Table 1, Example 54 differs from Examples 51 to 53 only in the content of resins (A) to (C). In Example 54, the content of resin (A) in the total photopolymerization components was 42% by mass, the content of resin (B) was 43% by mass, and the content of resin (C) was 15% by mass. In addition, in Example 54, the content of 1,6-hexanediol diacrylate in resin (B) was 42% by mass, and the content of bisacrylic acid (2,2-dimethylethylene) (5-ethyl-1,3-dioxan-2,5-diyl)methylene was 1% by mass.

[0189] As shown in Table 1, the viscosity of the photocurable acrylic resin for imprinting in Example 54 was 13.45 mPa·s. Furthermore, the photocurable acrylic resin for imprinting in Example 54 had a higher content of 1,6-hexanediol diacrylate compared to Examples 52 and 53. This is presumed to be why the viscosity of the photocurable acrylic resin for imprinting in Example 54 was lower than that of the photocurable acrylic resins for imprinting in Examples 52 and 53.

[0190] As shown in Table 2, the YI value of the cured product of the photocurable acrylic resin for imprinting in Example 54 after heat treatment was 1.4. From these results, it was confirmed that the cured product of Example 54 can maintain a low YI value even after heat treatment at 150°C. Furthermore, the photocurable acrylic resin for imprinting in Example 54 has a higher content of 1,6-hexanediol diacrylate compared to Examples 52 and 53. It is presumed that this is why the YI value of the cured product of the photocurable acrylic resin for imprinting in Example 54 was lower than that of the cured products of the photocurable acrylic resins for imprinting in Examples 52 and 53.

[0191] As shown in Table 2, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 54 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 91.8%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.6%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 54 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 91.9%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 91.3%.

[0192] In the cured product of Example 54, the difference ΔA (average transmittance before heat treatment - average transmittance after heat treatment) in the average transmittance of light in the wavelength range of 430 nm or more and 680 nm or less before and after heat treatment was -0.1%. In the cured product of Example 54, the difference ΔA in the average transmittance of light in the wavelength range of 430 nm or more and 510 nm or less before and after heat treatment was +0.3%. From the above results, it was confirmed that even when the cured product of Example 54 was subjected to a heat treatment at 150°C, the average transmittance of light in the wavelength range of 430 nm or more and 680 nm or less, and the average transmittance of light in the wavelength range of 430 nm or more and 510 nm or less hardly decreased. Further, in the imprint photocurable acrylic resin of Example 54, the content of 1,6 - hexanediol diacrylate is higher compared to Examples 52 and 53. Thus, it is presumed that the difference ΔA in the average transmittance of the cured product of the imprint photocurable acrylic resin of Example 54 became smaller than the difference ΔA in the average transmittance of the cured products of the imprint photocurable acrylic resins of Examples 52 and 53.

[0193] As shown in Table 2, the storage elastic modulus at 30°C of the cured product of the imprint photocurable acrylic resin of Example 54 was 2.3×10 ９ Pa. The storage elastic modulus at 110°C of the cured product of the imprint photocurable acrylic resin of Example 54 was 1.9×10 ８ Pa. The storage elastic modulus at 120°C of the cured product of the imprint photocurable acrylic resin of Example 54 was 2.2×10 ８ Pa. The storage elastic modulus at 130°C of the cured product of the imprint photocurable acrylic resin of Example 54 was 2.3×10 ８ Pa. From the above results, the cured product of Example 54 had a storage elastic modulus of 2.3×10 ９It was confirmed that it possessed a high storage modulus of Pa. Furthermore, it was confirmed that the decrease in storage modulus was suppressed even when the cured product of Example 54 was subjected to a heat treatment at 150°C. In addition, the photocurable acrylic resin for imprinting in Example 54 had a higher resin (C) content compared to Example 51. As a result, it is presumed that the storage modulus of the cured product of the photocurable acrylic resin for imprinting in Example 54 was greater than that of the cured product of the photocurable acrylic resin for imprinting in Example 51.

[0194] As shown in Table 2, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 54 was 58.0°C. From these results, it was confirmed that, despite the glass transition temperature Tg being less than 110°C, the cured product of Example 54 was able to keep the YI value low after heat treatment at 150°C, maintain a high average transmittance after heat treatment at 150°C, and further suppress the decrease in storage modulus after heat treatment at 150°C. In addition, the photocurable acrylic resin for imprinting in Example 54 had a higher content of 1,6-hexanediol diacrylate compared to Examples 52 and 53. As a result, it is presumed that the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 54 was lower than that of the cured products of the photocurable acrylic resins for imprinting in Examples 52 and 53.

[0195]

[0196]

[0197] [Example 55] As shown in Table 3, Example 55 differs from Example 54 only in the content of 1,6-hexanediol diacrylate and (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid in resin (B). In Example 55, the content of 1,6-hexanediol diacrylate in resin (B) was 1% by mass, and the content of (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid was 42% by mass.

[0198] As shown in Table 3, the viscosity of the photocurable acrylic resin for imprinting in Example 55 was 85.01 mPa·s. Furthermore, the photocurable acrylic resin for imprinting in Example 55 had a lower content of 1,6-hexanediol diacrylate and a higher content of (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid compared to Example 54. It is presumed that this resulted in a higher viscosity for the photocurable acrylic resin for imprinting in Example 55 than for the photocurable acrylic resin for imprinting in Example 54.

[0199] As shown in Table 4, the YI value of the cured product of the photocurable acrylic resin for imprinting in Example 55 after heat treatment was 1.1. From these results, it was confirmed that a low YI value can be maintained even when the cured product of Example 55 is subjected to heat treatment at 150°C.

[0200] As shown in Table 4, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 55 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 91.9%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.7%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 55 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 92.0%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 91.5%.

[0201] In the cured product of Example 55, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was -0.2%. In the cured product of Example 55, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +0.1%. From these results, it was confirmed that even when the cured product of Example 55 is subjected to heat treatment at 150°C, the average transmittance for light in the wavelength range of 430 nm to 680 nm and the average transmittance for light in the wavelength range of 430 nm to 510 nm hardly decreases.

[0202] As shown in Table 4, the storage modulus at 30°C of the cured photocurable acrylic resin for imprinting in Example 55 is 2.6 × 10⁻⁶. ９ The pressure was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting in Example 55 at 110°C was 1.5 × 10⁻⁶. ８ The pressure was Pa. The storage modulus at 120°C of the cured photocurable acrylic resin for imprinting in Example 55 was 1.4 × 10⁻⁶. ８ The storage modulus at 130°C for the cured product of the photocurable acrylic resin for imprinting in Example 55 was 1.4 × 10⁻⁶. ８ The result was Pa. From the above results, the cured product of Example 55 was 2.6 × 10 before heat treatment. ９ It was confirmed that it possessed a high storage modulus of Pa. Furthermore, it was confirmed that the decrease in storage modulus was suppressed even when the cured product of Example 55 was subjected to a heat treatment at 150°C.

[0203] As shown in Table 4, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 55 was 70.1°C. From these results, it was confirmed that, despite the glass transition temperature Tg being less than 110°C, the cured product of Example 55 was able to keep the YI value low after heat treatment at 150°C, maintain a high average transmittance after heat treatment at 150°C, and further suppress the decrease in storage modulus after heat treatment at 150°C. In addition, the photocurable acrylic resin for imprinting in Example 55 had a higher content of (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid compared to Example 54. As a result, it is presumed that the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 55 was higher than that of the cured product of the photocurable acrylic resin for imprinting in Example 54.

[0204] [Example 56] As shown in Table 3, Example 56 contains only resin (A), resin (B), and resin (C) as photopolymerization components, and further contains a photopolymerization initiator. Phenyl ethyl acrylate (PEA) was used as resin (A). The phenyl ethyl acrylate used was "Viscoat #192HP" manufactured by Osaka Organic Chemical Industry Co., Ltd. As resin (B), (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate and 1,6-hexanediol diacrylate were used. The (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate used was "KAYARAD R-684" manufactured by Nippon Kayaku Co., Ltd. The 1,6-hexanediol diacrylate used was "A-HD-N" manufactured by Shin Nakamura Chemical Industry Co., Ltd. Dipentaerythritol hexaacrylate (DPHA) was used as resin (C). The dipentaerythritol hexaacrylate used was the product name "KAYARAD DPHA" manufactured by Nippon Kayaku Co., Ltd. The photopolymerization initiator used was the product name "Irgacure 819" manufactured by IGM Resins B. V. In Example 56, the content of resin (A) in the total photopolymerization components was set to 20% by mass, the content of resin (B) to 60% by mass, and the content of resin (C) to 20% by mass. In Example 56, the ratio of 1,6-hexanediol diacrylate to (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate in resin (B) was set to 1:1. In Example 56, the content of the photopolymerization initiator was set to 0.5% by mass when the total content of the photopolymerization components was set to 100% by mass.

[0205] As shown in Table 3, the viscosity of the photocurable acrylic resin for imprinting in Example 56 was 26.20 mPa·s.

[0206] As shown in Table 4, the YI value of the cured product of the photocurable acrylic resin for imprinting in Example 56 after heat treatment was 2.3. From these results, it was confirmed that a low YI value can be maintained even when the cured product of Example 56 is subjected to heat treatment at 150°C.

[0207] As shown in Table 4, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 56 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 91.7%, and the average transmittance of the cured product for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.5%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 56 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 91.1%, and the average transmittance of the cured product for light in the wavelength range of 430 nm to 510 nm after heat treatment was 90.0%.

[0208] In the cured product of Example 56, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was +0.6%. In the cured product of Example 56, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +1.5%. From these results, it was confirmed that even when the cured product of Example 56 is subjected to heat treatment at 150°C, the average transmittance for light in the wavelength range of 430 nm to 680 nm and the average transmittance for light in the wavelength range of 430 nm to 510 nm hardly decreases.

[0209] As shown in Table 4, the storage modulus at 30°C of the cured photocurable acrylic resin for imprinting in Example 56 is 3.0 × 10⁻⁶. ９ The pressure was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting in Example 56 at 110°C was 1.0 × 10⁻⁶. ９ The pressure was Pa. The storage modulus at 120°C of the cured product of the photocurable acrylic resin for imprinting in Example 56 was 8.6 × 10⁻⁶. ８ The storage modulus at 130°C for the cured photocurable acrylic resin for imprinting in Example 56 was 7.4 × 10⁻⁶. ８ The result was Pa. From the above results, the cured product of Example 56 was 3.0 × 10 before heat treatment. ９It was confirmed that it possessed a high storage modulus of Pa. Furthermore, it was confirmed that the decrease in storage modulus was suppressed even when the cured product of Example 56 was subjected to a heat treatment at 150°C.

[0210] As shown in Table 4, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 56 was 109.3°C. From these results, it was confirmed that, despite the glass transition temperature Tg being less than 110°C, the cured product of Example 56 was able to keep the YI value low after heat treatment at 150°C, maintain a high average transmittance after heat treatment at 150°C, and further suppress the decrease in storage modulus after heat treatment at 150°C.

[0211] [Example 57] As shown in Table 3, Example 57 differs from Example 52 only in the resin (C). In Example 57, tris-(2-acryloxyethyl) isocyanurate was used as the resin (C). The tris-(2-acryloxyethyl) isocyanurate used was product name "A-9300S" manufactured by Shin Nakamura Chemical Industry Co., Ltd.

[0212] As shown in Table 3, the viscosity of the photocurable acrylic resin for imprinting in Example 57 was 20.47 mPa·s. Since there was almost no difference in viscosity between Example 52 and Example 57, it was found that even if the resin (C) is a different substance, the photocurable acrylic resin for imprinting has a low viscosity.

[0213] As shown in Table 4, the YI value of the cured product of the photocurable acrylic resin for imprinting in Example 57 was 1.0. From these results, it was confirmed that the cured product of Example 57 could maintain a low YI value even after being subjected to a heat treatment at 150°C. Furthermore, since there was almost no difference in the YI values ​​of the cured products of Example 52 and Example 57, it was found that even if the resin (C) is a different substance, the cured product of the photocurable acrylic resin for imprinting can maintain a low YI value.

[0214] As shown in Table 4, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 57 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 91.9%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.7%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 57 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 91.8%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 91.4%. Since there is almost no difference in the average transmittance of the cured product of Example 52 and the cured product of Example 57, it was found that even if the resin (C) is a different substance, the cured product of the photocurable acrylic resin for imprinting can maintain a high average transmittance.

[0215] In the cured product of Example 57, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was +0.1%. In the cured product of Example 57, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +0.4%. From these results, it was confirmed that even when the cured product of Example 57 was subjected to heat treatment at 150°C, the average transmittance for light in the wavelength range of 430 nm to 680 nm and the average transmittance for light in the wavelength range of 430 nm to 510 nm hardly decreased. Furthermore, since there was almost no difference in the difference in average transmittance ΔA between the cured product of Example 52 and the cured product of Example 57, it was found that even if the resin (C) is a different material, the average transmittance of the cured product of the photocurable acrylic resin for imprinting hardly decreases even when subjected to heat treatment at 150°C.

[0216] As shown in Table 4, the storage modulus at 30°C of the cured photocurable acrylic resin for imprinting in Example 57 is 2.5 × 10⁻⁶. ９ The temperature was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting in Example 57 at 110°C was 1.8 × 10⁻⁶.８ The pressure was Pa. The storage modulus at 120°C of the cured product of the photocurable acrylic resin for imprinting in Example 57 was 1.5 × 10⁻⁶. ８ The pressure was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting in Example 57 at 130°C was 1.5 × 10⁻⁶. ８ The result was Pa. From the above results, the cured product of Example 57 was 2.5 × 10 before heat treatment. ９ It was confirmed that it possessed a high storage modulus of Pa. Furthermore, it was confirmed that the decrease in storage modulus was suppressed even when the cured product of Example 57 was subjected to a heat treatment at 150°C. In addition, since there was almost no difference in the storage modulus between the cured product of Example 52 and the cured product of Example 57, it was found that even if the resin (C) is a different substance, the cured product of the photocurable acrylic resin for imprinting has a high storage modulus.

[0217] As shown in Table 4, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 57 was 80.4°C. From these results, it was confirmed that, despite the glass transition temperature Tg being less than 110°C, the cured product of Example 57 was able to keep the YI value low after heat treatment at 150°C, maintain a high average transmittance after heat treatment at 150°C, and further suppress the decrease in storage modulus after heat treatment at 150°C.

[0218] [Example 58] As shown in Table 3, Example 58 differs from Example 52 only in the resin (A). In Example 58, benzyl acrylate was used as resin (A). The benzyl acrylate used was "Benzyl Acrylate V #160" manufactured by Osaka Organic Chemical Industry Co., Ltd.

[0219] As shown in Table 3, the viscosity of the photocurable acrylic resin for imprinting in Example 58 was 11.12 mPa·s. The viscosity of benzyl acrylate is lower than that of phenylethyl acrylate. Therefore, it is inferred that the viscosity of the photocurable acrylic resin for imprinting in Example 58 was lower than that of the photocurable acrylic resin for imprinting in Example 52.

[0220] As shown in Table 4, the YI value of the cured product of the photocurable acrylic resin for imprinting in Example 58 was 2.7. From these results, it was confirmed that the cured product of Example 58 could maintain a low YI value even after being subjected to a heat treatment at 150°C. Furthermore, since there was almost no difference in the YI values ​​of the cured products of Example 52 and Example 58, it was found that even if the resin (A) is a different substance, the cured product of the photocurable acrylic resin for imprinting can maintain a low YI value.

[0221] As shown in Table 4, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 58 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 91.9%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.7%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting in Example 58 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 91.4%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 90.2%. Since there is almost no difference in the average transmittance of the cured product of Example 52 and the cured product of Example 58, it was found that even if the resin (A) is a different substance, the cured product of the photocurable acrylic resin for imprinting can maintain a high average transmittance.

[0222] In the cured product of Example 58, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was +0.5%. In the cured product of Example 58, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +1.6%. From these results, it was confirmed that even when the cured product of Example 58 was subjected to heat treatment at 150°C, the average transmittance for light in the wavelength range of 430 nm to 680 nm and the average transmittance for light in the wavelength range of 430 nm to 510 nm hardly decreased. Furthermore, since there was almost no difference in the difference in average transmittance ΔA between the cured product of Example 52 and the cured product of Example 58, it was found that even if the resin (A) is a different material, the average transmittance of the cured product of the photocurable acrylic resin for imprinting hardly decreases even when heat treatment is applied.

[0223] As shown in Table 4, the storage modulus at 30°C of the cured photocurable acrylic resin for imprinting in Example 58 is 2.8 × 10⁻⁶. ９ The storage modulus at 110°C for the cured photocurable acrylic resin for imprinting in Example 58 was 3.7 × 10⁻⁶. ８ The pressure was Pa. The storage modulus at 120°C of the cured product of the photocurable acrylic resin for imprinting in Example 58 was 2.9 × 10⁻⁶. ８ The storage modulus at 130°C for the cured photocurable acrylic resin for imprinting in Example 58 was 2.5 × 10⁻⁶. ８ The result was Pa. From the above results, the cured product of Example 58 was 2.8 × 10 before heat treatment. ９ It was confirmed that it possessed a high storage modulus of Pa. Furthermore, it was confirmed that the decrease in storage modulus was suppressed even when the cured product of Example 58 was subjected to a heat treatment at 150°C. In addition, since there was almost no difference in the storage modulus between the cured product of Example 52 and the cured product of Example 58, it was found that even if the resin (A) is a different substance, the cured product of the photocurable acrylic resin for imprinting has a high storage modulus.

[0224] As shown in Table 4, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 58 was 98.2°C. From these results, it was confirmed that, despite the glass transition temperature Tg being less than 110°C, the cured product of Example 58 was able to keep the YI value low after heat treatment at 150°C, maintain a high average transmittance after heat treatment at 150°C, and further suppress the decrease in storage modulus after heat treatment at 150°C.

[0225] From the above results, it was confirmed that in Examples 51 to 58, the viscosity of the photocurable acrylic resin for imprinting at 25°C was 90 mPa·s or less. Furthermore, in Examples 51 to 58, it was confirmed that the YI value of the cured product of the photocurable acrylic resin for imprinting after being held at 150°C for 500 hours was 3.0 or less. In Examples 51 to 58, it was confirmed that the average transmittance of the cured product of the photocurable acrylic resin for imprinting after being held at 150°C for 500 hours for light in the wavelength range of 430 nm to 680 nm was 91% or more, and the average transmittance of the cured product for light in the wavelength range of 430 nm to 510 nm was 90% or more. Furthermore, in Examples 51 to 58, the storage modulus of the cured product of the photocurable acrylic resin for imprinting at 30°C was 2.0 × 10⁻⁶. ９ The pressure is Pa or higher, and the storage modulus of the cured product at 120°C is 1.3 × 10⁻⁶. ８ The pressure is Pa or higher, and the storage modulus of the cured product at 130°C is 1.4 × 10⁻⁶. ８ It was confirmed to be Pa or higher.

[0226]

[0227]

[0228] [Comparative Example 51] As shown in Table 5, Comparative Example 51 contains only resin (B) and resin (C) as photopolymerization components, and further contains a photopolymerization initiator. In other words, Comparative Example 51 does not contain resin (A). In Comparative Example 51, bisacrylic acid (2,2-dimethylethylene) (5-ethyl-1,3-dioxan-2,5-diyl)methylene and 1,6-hexanediol diacrylate were used as resin (B). Bisacrylic acid (2,2-dimethylethylene) (5-ethyl-1,3-dioxan-2,5-diyl)methylene was the product name "KAYARAD R-604" manufactured by Nippon Kayaku Co., Ltd. The 1,6-hexanediol diacrylate was the product name "A-HD-N" manufactured by Shin Nakamura Chemical Industry Co., Ltd. Dipentaerythritol hexaacrylate (DPHA) was used as resin (C). The dipentaerythritol hexaacrylate used was "KAYARAD DPHA," a product manufactured by Nippon Kayaku Co., Ltd. The photopolymerization initiator used was "Irgacure 819," a product manufactured by IGM Resins B. V. In Comparative Example 51, the content of resin (B) in the total photopolymerization component was 85.8% by mass, and the content of resin (C) was 14.2% by mass. In Comparative Example 51, the ratio of 1,6-hexanediol diacrylate to bisacrylic acid (2,2-dimethylethylene) (5-ethyl-1,3-dioxan-2,5-diyl)methylene in resin (B) was 1:1. Furthermore, in Comparative Example 51, the content of the photopolymerization initiator was 0.5% by mass when the total content of the photopolymerization component was 100% by mass.

[0229] As shown in Table 5, the viscosity of the photocurable acrylic resin for imprinting in Comparative Example 51 was 83.20 mPa·s.

[0230] As shown in Table 6, the YI value of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 51 after heat treatment was 3.6. From these results, it was confirmed that the YI value of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 51 was slightly higher after heat treatment at 150°C.

[0231] As shown in Table 6, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 51 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 92.2%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 92.1%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 51 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 91.7%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 89.9%. From these results, it was confirmed that the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 51 for light in the wavelength range of 430 nm to 510 nm after heat treatment at 150°C was low, at less than 90%.

[0232] In the cured product of Comparative Example 51, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was +0.5%. In the cured product of Comparative Example 51, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +2.2%. From these results, it was confirmed that the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm becomes large in the cured product of the photocurable acrylic resin for imprinting in Comparative Example 51 before and after heat treatment at 150°C.

[0233] As shown in Table 6, the storage modulus at 30°C of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 51 is 2.8 × 10⁻⁶. ９ The storage modulus at 110°C for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 51 was 1.3 × 10⁻⁶. ９ The storage modulus at 120°C for the cured photocurable acrylic resin for imprinting in Comparative Example 51 was 1.2 × 10⁻⁶. ９The storage modulus at 130°C for the cured photocurable acrylic resin for imprinting in Comparative Example 51 was 1.1 × 10⁻⁶. ９ It was Pa.

[0234] As shown in Table 6, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 51 was 107.9°C.

[0235] [Comparative Example 52] As shown in Table 5, Comparative Example 52 contains only resin (B), resin (C), and monofunctional acrylate monomer as photopolymerization components, and further contains a photopolymerization initiator. In other words, Comparative Example 52 does not contain resin (A). In Comparative Example 52, isobornyl acrylate was used as the monofunctional acrylate monomer. The isobornyl acrylate used was the product name "IBOA-B" manufactured by Daicel Ornex Co., Ltd. As resin (B), (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate and 1,6-hexanediol diacrylate were used. The (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate used was the product name "KAYARAD R-684" manufactured by Nippon Kayaku Co., Ltd. For 1,6-hexanediol diacrylate, the product name "A-HD-N" manufactured by Shin Nakamura Chemical Industry Co., Ltd. was used. For resin (C), dipentaerythritol hexaacrylate (DPHA) was used. For dipentaerythritol hexaacrylate, the product name "KAYARAD DPHA" manufactured by Nippon Kayaku Co., Ltd. was used. For the photopolymerization initiator, the product name "Irgacure 819" manufactured by IGM Resins B. V. was used. In Comparative Example 52, the content of monofunctional acrylate monomers in the total photopolymerization components was set to 30% by mass, the content of resin (B) was set to 60% by mass, and the content of resin (C) was set to 10% by mass. In Comparative Example 52, the ratio of 1,6-hexanediol diacrylate to (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate in resin (B) was set to 1:1. Also in Comparative Example 52, the content of the photopolymerization initiator was set to 0.5% by mass when the total content of the photopolymerization components was set to 100% by mass.

[0236] As shown in Table 5, the viscosity of the photocurable acrylic resin for imprinting in Comparative Example 52 was 19.00 mPa·s.

[0237] As shown in Table 6, the YI value of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 52 after heat treatment was 15.8. From these results, it was confirmed that the YI value of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 52 becomes high after heat treatment at 150°C.

[0238] As shown in Table 6, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 52 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 92.0%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.9%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 52 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 87.0%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 79.8%. From these results, it was confirmed that the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 52 decreased after heat treatment at 150°C.

[0239] In the cured product of Comparative Example 52, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was +5.0%. In the cured product of Comparative Example 52, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +12.0%. From these results, it was confirmed that the difference in average transmittance ΔA for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 52 becomes large before and after heat treatment at 150°C.

[0240] As shown in Table 6, the storage modulus at 30°C of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 52 is 2.0 × 10⁻⁶. ９The storage modulus at 110°C for the cured photocurable acrylic resin for imprinting in Comparative Example 52 was 9.4 × 10⁻⁶. ８ The pressure was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 52 at 120°C was 8.6 × 10⁻⁶. ８ The storage modulus at 130°C for the cured photocurable acrylic resin for imprinting in Comparative Example 52 was 7.8 × 10⁻⁶. ８ It was Pa.

[0241] As shown in Table 6, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 52 was 180.6°C.

[0242] [Comparative Example 53] As shown in Table 5, Comparative Example 53 differs from Comparative Example 52 only in the content of resin (B), resin (C), and monofunctional acrylate monomer. In Comparative Example 53, the content of resin (B) in the total photopolymerization components was 60% by mass, the content of resin (C) was 20% by mass, and the content of monofunctional acrylate monomer was 20% by mass. In addition, in Comparative Example 53, the content of 1,6-hexanediol diacrylate in resin (B) was 20% by mass, and the content of (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate was 40% by mass.

[0243] As shown in Table 5, the viscosity of the photocurable acrylic resin for imprinting in Comparative Example 53 was 25.28 mPa·s.

[0244] As shown in Table 6, the YI value of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 53 after heat treatment was 29.4. From these results, it was confirmed that the YI value of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 53 became significantly higher after heat treatment at 150°C.

[0245] As shown in Table 6, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 53 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 91.9%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.7%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 53 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 82.4%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 69.3%. From these results, it was confirmed that the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 53 becomes significantly lower after heat treatment at 150°C.

[0246] In the cured product of Comparative Example 53, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was +9.5%. In the cured product of Comparative Example 53, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +22.4%. From these results, it was confirmed that the difference in average transmittance ΔA for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 53 becomes significantly larger before and after heat treatment at 150°C.

[0247] As shown in Table 6, the storage modulus at 30°C of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 53 is 2.8 × 10⁻⁶. ９ The storage modulus at 110°C for the cured photocurable acrylic resin for imprinting in Comparative Example 53 was 1.2 × 10⁻⁶. ９ The storage modulus at 120°C for the cured photocurable acrylic resin for imprinting in Comparative Example 53 was 1.1 × 10⁻⁶. ９ The storage modulus at 130°C for the cured photocurable acrylic resin for imprinting in Comparative Example 53 was 9.6 × 10⁻⁶. ８ It was Pa.

[0248] As shown in Table 6, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 53 was 139.0°C.

[0249] [Comparative Example 54] As shown in Table 5, Comparative Example 54 contains only resin (B), resin (C), and monofunctional acrylate monomer as photopolymerization components, and further contains a photopolymerization initiator. In other words, Comparative Example 54 does not contain resin (A). In Comparative Example 54, isobornyl acrylate was used as the monofunctional acrylate monomer. The isobornyl acrylate used was the product name "IBOA-B" manufactured by Daicel Ornex Co., Ltd. As resin (B), (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid was used. The product name "KAYARAD R-604" manufactured by Nippon Kayaku Co., Ltd. was used. As resin (C), a polyfunctional polyester acrylate was used. The polyfunctional polyester acrylate used was "M-9050," manufactured by Toagosei Co., Ltd. The photopolymerization initiator used was "Irgacure 819," manufactured by IGM Resins B.V. In Comparative Example 54, the content of monofunctional acrylate monomers in the total photopolymerization component was 30% by mass, the content of resin (B) was 50% by mass, and the content of resin (C) was 20% by mass. Furthermore, in Comparative Example 54, the content of the photopolymerization initiator was 0.5% by mass when the total content of the photopolymerization component was 100% by mass.

[0250] As shown in Table 5, the viscosity of the photocurable acrylic resin for imprinting in Comparative Example 54 was 192.50 mPa·s.

[0251] As shown in Table 6, the YI value of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 54 after heat treatment was 45.1. From these results, it was confirmed that the YI value of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 54 becomes significantly higher after heat treatment at 150°C.

[0252] As shown in Table 6, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 54 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 92.1%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.8%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 54 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 77.2%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 57.4%. From these results, it was confirmed that the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 54 becomes significantly lower after heat treatment at 150°C.

[0253] In the cured product of Comparative Example 54, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was +14.9%. In the cured product of Comparative Example 54, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +34.4%. From these results, it was confirmed that the difference in average transmittance ΔA for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 54 becomes significantly larger before and after heat treatment at 150°C.

[0254] As shown in Table 6, the storage modulus at 30°C of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 54 is 2.1 × 10⁻⁶. ９ The storage modulus at 110°C for the cured photocurable acrylic resin for imprinting in Comparative Example 54 was 2.9 × 10⁻⁶. ７ The storage modulus at 120°C for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 54 was 3.0 × 10⁻⁶. ７ The storage modulus at 130°C for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 54 was 3.1 × 10⁻⁶. ７ It was Pa.

[0255] As shown in Table 6, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 54 was 169.6°C.

[0256]

[0257]

[0258] [Comparative Example 55] As shown in Table 7, Comparative Example 55 contains only resin (A) and resin (B) as photopolymerization components, and includes "Irgacure TPO" manufactured by IGM Resins B. V. as a photopolymerization initiator. In Comparative Example 55, benzyl acrylate was used as resin (A). The benzyl acrylate used was "Benzyl Acrylate V #160" manufactured by Osaka Organic Chemical Industry Co., Ltd. As resin (B), (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate was used. The (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate used was "KAYARAD R-684" manufactured by Nippon Kayaku Co., Ltd. In Comparative Example 55, the content of resin (A) in the total photopolymerization component was set to 75% by mass, and the content of resin (B) was set to 25% by mass. In addition, in Comparative Example 55, the content of the photopolymerization initiator was set to 3% by mass when the total content of the photopolymerization component was set to 100% by mass.

[0259] As shown in Table 7, the viscosity of the photocurable acrylic resin for imprinting in Comparative Example 55 was 4.20 mPa·s.

[0260] As shown in Table 8, the YI value of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 55 was 18.8. From these results, it was confirmed that in Comparative Example 55, the content of resin (A) exceeded 42% by mass, and the content of resin (B) was less than 43% by mass, which resulted in a high YI value after heat treatment at 150°C for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 55.

[0261] As shown in Table 8, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 55 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 91.4%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.2%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 55 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 85.5%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 75.1%. From these results, it was confirmed that because the content of resin (A) in Comparative Example 55 exceeds 42% by mass and the content of resin (B) is less than 43% by mass, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 55 after heat treatment at 150°C is significantly low.

[0262] In the cured product of Comparative Example 55, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was +5.9%. In the cured product of Comparative Example 55, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +16.1%. From these results, it was confirmed that in Comparative Example 55, the content of resin (A) exceeds 42% by mass, and the content of resin (B) is less than 43% by mass, so the difference in average transmittance ΔA before and after heat treatment of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 55 becomes significantly larger.

[0263] As shown in Table 8, the storage modulus at 30°C of the cured photocurable acrylic resin for imprinting in Comparative Example 55 is 7.3 × 10⁻⁶. ８ The storage modulus at 110°C for the cured photocurable acrylic resin for imprinting in Comparative Example 55 was 1.2 × 10⁻⁶. ７ The pressure was Pa. The storage modulus at 120°C of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 55 was 1.2 × 10⁻⁶. ７The storage modulus at 130°C for the cured photocurable acrylic resin for imprinting in Comparative Example 55 was 1.3 × 10⁻⁶. ７ The result was Pa. From these results, it was confirmed that in Comparative Example 55, the content of resin (A) exceeds 42% by mass, and the content of resin (B) is less than 43% by mass. Therefore, when heat treatment is applied to the cured product of the photocurable acrylic resin for imprinting in Comparative Example 55, the storage modulus decreases significantly.

[0264] As shown in Table 8, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 55 was 35.4°C. From these results, it was confirmed that the glass transition temperature Tg of the cured product of Comparative Example 55 was significantly low because the content of resin (A) exceeded 42% by mass and the content of resin (B) was less than 43% by mass.

[0265] [Comparative Example 56] As shown in Table 7, Comparative Example 56 differs from Comparative Example 55 only in the content of resin (A) and resin (B). In Comparative Example 56, the content of resin (A) in the total photopolymerization component was 60% by mass, and the content of resin (B) was 40% by mass.

[0266] As shown in Table 7, the viscosity of the photocurable acrylic resin for imprinting in Comparative Example 56 was 6.60 mPa·s.

[0267] As shown in Table 8, the YI value of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 56 was 18.4. From these results, it was confirmed that in Comparative Example 56, the content of resin (A) exceeded 42% by mass, and the content of resin (B) was less than 43% by mass, which resulted in a high YI value after heat treatment at 150°C for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 56.

[0268] As shown in Table 8, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 56 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 91.6%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.3%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 56 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 85.8%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 75.4%. From these results, it was confirmed that because the content of resin (A) in Comparative Example 56 exceeds 42% by mass and the content of resin (B) is less than 43% by mass, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 56 after heat treatment at 150°C is significantly low.

[0269] In the cured product of Comparative Example 56, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was +5.8%. In the cured product of Comparative Example 56, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +15.9%. From these results, it was confirmed that in Comparative Example 56, the content of resin (A) exceeds 42% by mass, and the content of resin (B) is less than 43% by mass, so the difference in average transmittance ΔA before and after heat treatment of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 56 becomes significantly large.

[0270] As shown in Table 8, the storage modulus at 30°C of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 56 is 2.1 × 10⁻⁶. ９ The storage modulus at 110°C for the cured photocurable acrylic resin for imprinting in Comparative Example 56 was 3.0 × 10⁻⁶. ７ The storage modulus at 120°C for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 56 was 3.1 × 10⁻⁶. ７The storage modulus at 130°C for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 56 was 3.2 × 10⁻⁶. ７ The result was Pa. From the above results, it was confirmed that in Comparative Example 56, the content of resin (A) exceeds 42% by mass, and the content of resin (B) is less than 43% by mass. Therefore, when heat treatment is applied to the cured product of the photocurable acrylic resin for imprinting in Comparative Example 56, the storage modulus decreases significantly.

[0271] As shown in Table 8, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 56 was 46.0°C. From these results, it was confirmed that the glass transition temperature Tg of the cured product of Comparative Example 56 is low because the content of resin (A) exceeds 42% by mass and the content of resin (B) is less than 43% by mass.

[0272] [Comparative Example 57] As shown in Table 7, Comparative Example 57 contains only a monofunctional monomer and resin (B) and resin (C) as photopolymerization components, and includes "IrgacureTPO" manufactured by IGM Resins B.V. as a photopolymerization initiator. In Comparative Example 57, N-vinyl-2-pyrrolidone was used as the monofunctional monomer. N-vinyl-2-pyrrolidone has a viscosity of 1.7 mPa·s at 25°C. In addition, 1,9-nonanediol diacrylate (NDDA) and silicone diacrylate were used as resin (B). In addition, trimethylolpropane triacrylate (TMPTA) was used as resin (C). In Comparative Example 57, the content of monofunctional monomer in the total photopolymerization components was 32% by mass, the content of resin (B) was 34% by mass, and the content of resin (C) was 32% by mass. Furthermore, in resin (B), the content of 1,9-nonanediol diacrylate was set to 33% by mass, and the content of silicone diacrylate was set to 1% by mass. In comparative example 57, the content of the photopolymerization initiator was set to 2% by mass when the total content of the photopolymerization components was set to 100% by mass.

[0273] As shown in Table 7, the viscosity of the photocurable acrylic resin for imprinting in Comparative Example 57 was 7.90 mPa·s.

[0274] As shown in Table 8, the YI value of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 57 was 56.7. From these results, it was confirmed that when the cured product of Comparative Example 57 was subjected to a heat treatment at 150°C, the YI value became significantly higher.

[0275] As shown in Table 8, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 57 for light in the wavelength range of 430 nm to 680 nm before heat treatment was 92.0%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm before heat treatment was 91.7%. Furthermore, the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 57 for light in the wavelength range of 430 nm to 680 nm after heat treatment was 73.0%, and the average transmittance for light in the wavelength range of 430 nm to 510 nm after heat treatment was 41.9%. From these results, it was confirmed that the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Comparative Example 57 becomes significantly lower after heat treatment at 150°C.

[0276] In the cured product of Comparative Example 57, the difference in average transmittance ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm to 680 nm before and after heat treatment was +19.0%. In the cured product of Comparative Example 57, the difference in average transmittance ΔA for light in the wavelength range of 430 nm to 510 nm before and after heat treatment was +49.8%. From these results, it was confirmed that the difference in average transmittance ΔA for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 57 becomes significantly larger before and after heat treatment at 150°C.

[0277] As shown in Table 8, the storage modulus at 30°C of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 57 is 2.4 × 10⁻⁶. ９ The storage modulus at 110°C for the cured photocurable acrylic resin for imprinting in Comparative Example 57 was 1.6 × 10⁻⁶. ９The storage modulus at 120°C for the cured product of the photocurable acrylic resin for imprinting in Comparative Example 57 was 1.5 × 10⁻⁶. ９ The storage modulus at 130°C for the cured photocurable acrylic resin for imprinting in Comparative Example 57 was 1.4 × 10⁻⁶. ９ It was Pa.

[0278] As shown in Table 8, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Comparative Example 57 was 180.1°C.

[0279] [Evaluation of Examples and Comparative Examples] Tables 9 and 10 below show the evaluation of heat resistance and viscosity for Examples 51-58 and Comparative Examples 51-57 in two stages. For the evaluation of heat resistance, the heat resistance was evaluated based on the optical properties after heat treatment and the shape after heat treatment. For the optical properties after heat treatment, if the YI value after heat treatment in which the cured product of the imprint-type photocurable acrylic resin was held at 150°C for 500 hours was 3 or less, the evaluation was "A", and if it was greater than 3, the evaluation was "B". For the shape after heat treatment, nanoimprint molding was performed on a substrate using a master plate and imprint-type photocurable acrylic resin to form a fine uneven structure on the substrate, and after heat treatment in which the cured product was held at 150°C for 500 hours, the cross-section of the cured product was observed with a transmission electron microscope (TEM). As a result, if there was no change in shape compared to before heat treatment, the evaluation was "A", and if there was a change in shape compared to before heat treatment, the evaluation was "B".

[0280] Viscosity was evaluated based on the conformability of the uncured photocurable acrylic resin for imprinting to the master disc and its appearance. For the conformability of the photocurable acrylic resin for imprinting to the master disc, a master disc with a known fine surface texture (cross-sectional structure) was prepared. Nanoimprint molding was performed on a substrate using the master disc and the photocurable acrylic resin for imprinting, and the fine surface texture on the substrate was observed cross-sectionally using a transmission electron microscope. As a result, if the fine surface texture formed on the substrate was similar to the fine surface texture of the master disc, the conformability was evaluated as high and rated as "A". If the fine surface texture on the substrate was clearly different from the fine surface texture of the master disc (for example, if the dimensions of the pattern of the fine surface texture on the substrate were extremely small compared to the fine surface texture of the master disc), the conformability was evaluated as poor and rated as "B". For appearance, nanoimprint molding was performed on a substrate using the master disc and the photocurable acrylic resin for imprinting, and the substrate with the formed fine surface texture was observed in a dark room using fluorescent light transmission and reflection. As a result, substrates that showed no distortion of the fine uneven structure pattern on the substrate, no peeling of the resin on the substrate, and were uniform throughout the substrate were given an evaluation of "A," while substrates that showed partial distortion of the fine uneven structure pattern, peeling of the resin on the substrate, or other inconsistencies throughout the substrate were given an evaluation of "B."

[0281]

[0282]

[0283] As shown in Table 9, the cured products of the photocurable acrylic resins for imprinting in Examples 51 to 58 received an evaluation of "A" for both their optical properties and shape after heat treatment. Furthermore, the photocurable acrylic resins for imprinting in Examples 51 to 58 also received an evaluation of "A" for their conformability to the master plate and their appearance. From these evaluations, it was confirmed that the photocurable acrylic resins for imprinting in Examples 51 to 58 possess both heat resistance and low viscosity.

[0284] On the other hand, as shown in Table 10, the cured products of the photocurable acrylic resins for imprinting in Comparative Examples 51 to 53 received a rating of "B" in terms of optical properties after heat treatment. From the above evaluation, it was confirmed that Comparative Examples 51 to 53, although having low viscosity, had poor heat resistance.

[0285] As shown in Table 10, the cured product of the photocurable acrylic resin for imprinting in Comparative Example 54 received a rating of "B" in terms of optical properties after heat treatment. Furthermore, the photocurable acrylic resin for imprinting in Comparative Example 54 also received a rating of "B" in terms of conformability to the master plate and appearance. From these evaluations, it was confirmed that Comparative Example 54 had low heat resistance and high viscosity.

[0286] As shown in Table 10, the cured products of the photocurable acrylic resins for imprinting in Comparative Examples 55 and 56 received a rating of "B" in terms of optical properties and shape after heat treatment. From the above evaluation, it was confirmed that Comparative Examples 55 and 56, although having low viscosity, had poor heat resistance.

[0287] As shown in Table 10, the cured product of the photocurable acrylic resin for imprinting in Comparative Example 57 received a rating of "B" in terms of optical properties after heat treatment. From the above evaluation, it was confirmed that Comparative Example 57, although having low viscosity, had poor heat resistance.

[0288] 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.

[0289] 1 Wire grid polarizing element 10 Substrate 20 Grid structure 21 Base portion 22 Protruding portion 22a Tip 22b Side 30 Reflective film

Claims

1. A photocurable acrylic resin for imprinting containing a photopolymerization component, wherein the photopolymerization component comprises resin (A) and resin (B), wherein resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, and resin (B) is a bifunctional compound, the content of resin (A) relative to the total photopolymerization component is 20% by mass or more and 42% by mass or less, and the content of resin (B) relative to the total photopolymerization component is 43% by mass or more and 66% by mass or less.

2. The photocurable acrylic resin for imprinting according to claim 1, wherein the photopolymerization component further comprises a resin (C), the resin (C) being an acrylate monomer having three or more functional groups, and the content of the resin (C) relative to the entire photopolymerization component being 1% by mass or more and 30% by mass or less.

3. The photocurable acrylic resin for imprinting according to claim 1 or 2, wherein the resin (A) is one or both of phenylethyl acrylate and benzyl acrylate.

4. The photocurable acrylic resin for imprinting according to claim 1 or 2, wherein the resin (B) is one or more selected from the group consisting of (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate, bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene, and 1,6-hexanediol diacrylate.

5. The photocurable acrylic resin for imprinting according to claim 4, wherein the resin (B) comprises one of 1,6-hexanediol diacrylate, (octahydro-4,7-methano-1H-indendiyl)bis(methylene) diacrylate, and (2,2-dimethylethylene)(5-ethyl-1,3-dioxan-2,5-diyl)methylene bisacrylic acid.

6. The photocurable acrylic resin for imprinting according to claim 2, wherein the resin (C) comprises one or both of dipentaerythritol hexaacrylate and tris-(2-acryloxyethyl) isocyanurate.

7. The photocurable acrylic resin for imprinting according to claim 1 or 2, wherein the viscosity of the photocurable acrylic resin for imprinting at 25°C is 90 mPa·s or less.

8. The photocurable acrylic resin for imprinting according to claim 1 or 2, wherein, after holding the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the YI value of the cured product is 3 or less.

9. At 30°C, the storage modulus of the cured product of the photocurable acrylic resin for imprinting is 2.0 × 10⁻⁶. ９ The pressure is Pa or higher, and the storage modulus of the cured product at 120°C is 1.3 × 10⁻⁶. ８ A photocurable acrylic resin for imprinting according to claim 1 or 2, wherein the pressure is Pa or higher.

10. The storage modulus of the cured product at 130°C is 1.4 × 10⁻⁶. ８ The photocurable acrylic resin for imprinting according to claim 9, wherein the pressure is Pa or higher.

11. The photocurable acrylic resin for imprinting according to claim 1 or 2, wherein, after holding the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the average transmittance of the cured product to light in the wavelength range of 430 nm to 680 nm is 91% or more, and the average transmittance of the cured product to light in the wavelength range of 430 nm to 510 nm is 90% or more.

12. A method for producing a photocurable acrylic resin for imprinting, comprising a photopolymerization component and a photopolymerization initiator for polymerizing the photopolymerization component, wherein the photopolymerization component comprises resin (A) and resin (B), wherein resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, resin (B) is a bifunctional compound, the content of resin (A) to the total photopolymerization component is 20% by mass or more and 42% by mass or less, the content of resin (B) to the total photopolymerization component is 43% by mass or more and 66% by mass or less, and the method for producing a photocurable acrylic resin for imprinting comprises mixing resin (A) and resin (B), and mixing the photopolymerization initiator into the mixed resin of resin (A) and resin (B).

13. A method for producing a photocurable acrylic resin for imprinting containing a photopolymerization component, wherein the photopolymerization component comprises resin (A), resin (B), and resin (C), wherein resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, resin (B) is a bifunctional compound, resin (C) is an acrylate monomer having three or more functional groups, the content of resin (A) to the total photopolymerization component is 20% by mass or more and 42% by mass or less, the content of resin (B) to the total photopolymerization component is 43% by mass or more and 66% by mass or less, and the content of resin (C) to the total photopolymerization component is 1% by mass or more and 30% by mass or less, and a first mixed resin is produced by mixing resin (A) and resin (B), and a second mixed resin is produced by mixing resin (C) to the first mixed resin. A method for producing photocurable acrylic resin for imprinting, including the following.

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