Surface protection plate, laminated member and image display device using same, and method for manufacturing surface protection plate

Abstract

The present invention provides a surface protection panel having a colored layer, said surface protection panel being capable of suppressing decrease in visibility if a functional member comprising a plastic film is bonded to the back surface of the surface protection panel, with an adhesive layer being interposed therebetween.　A surface protection panel which sequentially comprises, from the front surface side toward the back surface side, a functional layer A, a core layer that is mainly composed of a resin, and a functional layer B in this order, wherein the core layer comprises a colored layer in at least a part of the functional layer B-side surface.

Description

[Technical Field]

[0001] The present invention relates to a surface protection plate, a laminated member and an image display device using the same, and a method for manufacturing a surface protection plate. [Background technology]

[0002] 2. Description of the Related Art Image display devices such as liquid crystal display devices and organic EL display devices may have a bezel cover disposed around the periphery of the device surface for the purpose of concealing electrical circuits and the like inside the device.

[0003] However, image display devices with bezel covers on their surfaces have problems such as limitations on design and a loss of flatness of the display surface.In particular, many of the portable image display devices in recent years have built-in capacitance-type touch panels, and the presence of a bezel cover can catch fingers, reducing the operability of the touch panel.

[0004] For this reason, a method has been proposed in which decorative printing is applied to components that constitute an image display device (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-93977 A (Claim 8, Paragraphs 0038 and 0043) Summary of the Invention [Problem to be solved by the invention]

[0006] Patent document 1 describes an adhesive sheet with a decorative printing layer, in which one side of a base film is partially decoratively printed using gravure printing, screen printing, etc., and the side of the base film having the decorative printing layer is bonded to the adhesive side of a substrateless adhesive sheet.

[0007] The adhesive sheet with a decorative print layer of Patent Document 1 can provide hiding properties due to the decorative print layer, making it possible to omit a bezel cover. However, when a functional member including a plastic film is attached to the adhesive layer side of the adhesive sheet with a decorative print layer of Patent Document 1, there have been many cases where the visibility of the image display device has decreased.

[0008] The present invention has been made in consideration of the above-described circumstances, and aims to provide a surface protection plate having a colored layer that can suppress a decrease in visibility when a functional member including a plastic film is attached to the back surface of the surface protection plate via an adhesive layer. Another object of the present invention is to provide a method for easily manufacturing the surface protection plate. Another object of the present invention is to provide a laminated member that can suppress a decrease in visibility, and an image display device using the laminated member. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides the following [1] to

[15] . [1] A surface protection plate having, from the front side to the back side, a functional layer A, a core layer mainly composed of resin, and a functional layer B, in that order, and further having a colored layer on a portion of the surface of the core layer facing the functional layer B. [2] A surface protection plate described in [1], wherein the position of the surface of the colored layer on the functional layer B side and the position of the surface of the core layer on the functional layer B side in the area not having the colored layer are substantially identical in the thickness direction of the surface protection plate. [3] A surface protection plate according to [1] or [2], wherein the average inclination angle of the boundary between the area having the colored layer and the area not having the colored layer on the outermost surface on the back side of the surface protection plate is 0.10 degrees or less. [4] The surface protection plate according to any one of [1] to [3], wherein the area having the colored layer has a total light transmittance of 2% or less. [5] The surface protection plate according to any one of [1] to [4], wherein the area not having the colored layer has a total light transmittance of 50% or more. [6] The surface protection plate according to any one of [1] to [5], wherein the functional layer B has a layer different from the functional layer A. [7] The surface protection plate according to any one of [1] to [6], wherein the functional layer A includes a hard coat layer A, and the functional layer B includes a hard coat layer B. [8] The surface protection plate according to [7], wherein when the arithmetic mean roughness of the surface of the hard coat layer A is defined as Ra-A and the arithmetic mean roughness of the surface of the hard coat layer B is defined as Ra-B, the relationship Ra-A>Ra-B is satisfied. [9] A laminated member obtained by laminating a functional member having at least one plastic film on the back side of the surface protection plate according to any one of [1] to [8] via an adhesive layer.

[10] The laminated member according to [9], wherein there is no glass between the plastic film located closest to the surface protection plate of the functional member and the adhesive layer.

[11] The laminated member according to [9] or

[10] , wherein the functional member is a touch panel.

[12] An image display device comprising a laminated member according to any one of [9] to

[11] on a display element, the laminated member being arranged so that the surface of the laminated member on the functional member side faces the display element side.

[13] A method for producing a surface protection plate, comprising the following steps (1) and (2): (1) A process of placing a laminate A having a functional layer A on one side of a pair of injection molding molds, and placing a laminate B having a functional layer B and a colored layer on a portion of the functional layer B on the other side of the molds. (2) A step of clamping the mold, injecting an injection resin into the mold, and obtaining a laminate X in which the laminate A, a core layer containing the injected resin, and the laminate B are tightly adhered together.

[14] The method for producing a surface protection plate according to

[13] , wherein the laminate A is a transfer sheet A having a functional layer A on a release sheet, the laminate B is a transfer sheet B having a functional layer B on a release sheet and a colored layer on a part of the functional layer B, and the laminate X is a laminate obtained by closely adhering the surface of the transfer sheet A opposite to the release sheet, the core layer containing the injected resin, and the surface of the transfer sheet B opposite to the release sheet, and further comprising the following step (3): (3) A step of opening the mold and peeling off the release sheets of transfer sheet A and transfer sheet B from the laminate X.

[15] A method for producing a surface protection plate according to

[13] , wherein the laminate A is a laminate film A obtained by laminating a film layer A and a functional layer A, the laminate B is a transfer sheet B having a functional layer B on a release sheet and a colored layer on a portion of the functional layer B, and the laminate X is a laminate obtained by closely adhering the surface of the laminate film A opposite to the functional layer A, a core layer containing the injected resin, and the surface of the transfer sheet B opposite to the release sheet, and further comprising the following step (3): (3) A step of opening the mold and peeling off the release sheet of the transfer sheet B from the laminate X.

[0010] According to the surface protection plate of the present invention, it is possible to suppress a decrease in visibility when a functional member including a plastic film is attached to the back surface via an adhesive layer. Furthermore, the manufacturing method of the surface protection plate of the present invention can easily manufacture the surface protection plate. Furthermore, the laminated member of the present invention and the image display device using the same can suppress a decrease in visibility. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing one embodiment of a surface protection plate of the present invention. [Figure 2] FIG. 1 is a cross-sectional view showing an example of a conventional surface protection plate. [Figure 3] 1 is a cross-sectional view showing one embodiment of a laminated member of the present invention. [Figure 4]FIG. 1 is a cross-sectional view showing an example of a conventional laminated member. [Figure 5] 1 is a plan view showing an embodiment of a surface protection plate of the present invention. [Figure 6] 1 is a cross-sectional view showing one embodiment of a surface protection plate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] [Surface protection plate] The surface protection plate of the present invention has, from the front side to the back side, a functional layer A, a core layer mainly composed of resin, and a functional layer B, in that order, and further has a colored layer on a portion of the surface of the core layer facing the functional layer B.

[0013] FIG. 1 is a cross-sectional view showing one embodiment of a surface protection plate of the present invention. The surface protection plate (100) in Fig. 1 has, from the front side to the back side, a functional layer A (20A), a core layer (10) mainly composed of resin, and a functional layer B (20B) in this order. The surface protection plate (100) in Fig. 1 also has a colored layer (30) on a part of the surface of the core layer (10) facing the functional layer B (20B). Furthermore, the surface protection plate (100) of Figure 1 has substantially no slope at the boundary (BL) between the region (i) having the colored layer (30) and the region (ii) not having the colored layer (30) on the outermost surface on the back side of the surface protection plate. In this specification, the term "substantially not having a slope" is a concept that includes a flat surface.

[0014] FIG. 2 is a cross-sectional view showing an example of a conventional surface protection plate. The surface protection plate (100) of Figure 2 differs in configuration from the surface protection plate (100) of the present invention of Figure 1 in that, for example, the colored layer (30) is located on the side of functional layer B (20B) opposite the core layer (10), rather than between the core layer (10) and functional layer B (20B). Furthermore, the surface protection plate (100) in Figure 2 has a slope at the boundary (BL) between the area (i) having the colored layer (30) and the area (ii) not having the colored layer (30) on the outermost surface on the back side of the surface protection plate.

[0015] FIG. 6 is a cross-sectional view showing one embodiment of the surface protection plate of the present invention. The surface protection plate (100) of Figure 6 has, from the front side to the back side, a functional layer A (20A), a film layer A (24A), a core layer (10) mainly composed of resin, and a functional layer B (20B) in this order. The surface protection plate (100) of Figure 6 also has a colored layer (30) on a portion of the surface of the core layer (10) facing the functional layer B (20B). Although not shown, a primer layer may also be provided between the functional layer A (20A) and the film layer A (24A). Furthermore, the surface protection plate (100) of Figure 6 has substantially no slope at the boundary (BL) between the region (i) having the colored layer (30) and the region (ii) not having the colored layer (30) on the outermost surface on the back side of the surface protection plate. In this specification, the term "substantially not having a slope" is a concept that includes a flat surface.

[0016] The surface protection plate of the present invention has a colored layer on a portion of the surface of the core layer facing the functional layer B (in other words, has a colored layer between the core layer and the functional layer B), thereby preventing a gradient from occurring at the boundary between the area with the colored layer and the area without the colored layer on the outermost surface on the back side of the surface protection plate, and thus preventing a decrease in visibility when a functional component including a plastic film is attached to the back side of the surface protection plate via an adhesive layer. The reason why visibility decreases when there is a large gradient at the boundary between the area with the colored layer and the area without the colored layer is thought to be that the gradient is reflected in the plastic film (see Figure 4), causing the optical axis of the plastic film to change partially. Note that if the colored layer is located closer to the surface than the core layer, the above-mentioned problems do not occur, but the sense of depth is reduced, and the luxurious feel of the surface protection plate as a whole cannot be improved. On the other hand, when there is substantially no inclination at the boundary between the region having the colored layer and the region not having the colored layer, even if a functional member including a plastic film is attached to the back side of the surface protection plate, the change in the optical axis of the plastic film is suppressed, and it is thought that a decrease in visibility can be suppressed (see Figure 3). Furthermore, when there is substantially no inclination at the boundary between the region having the colored layer and the region not having the colored layer, it is also preferable in that it is easier to suppress the incorporation of air bubbles when a functional member including a plastic film is attached to the back side of the surface protection plate.

[0017] In one embodiment of the surface protection plate of the present invention, it is preferable that the position of the surface of the colored layer facing the functional layer B and the position of the surface of the core layer facing the functional layer B in the region without the colored layer are substantially the same in the thickness direction of the surface protection plate. By providing such a configuration, it is possible to substantially eliminate the gradient of the boundary between the region with the colored layer and the region without the colored layer on the outermost surface on the back side of the surface protection plate, and when a functional member including a plastic film is attached to the back side of the surface protection plate, it is possible to further suppress a decrease in visibility and suppress the inclusion of air bubbles.

[0018] Examples of means for making the position of the surface of the colored layer facing the functional layer B and the position of the surface of the core layer facing the functional layer B in the area not having the colored layer substantially the same in the thickness direction of the surface protection plate include injection molding such as in-mold molding, which will be described later. In injection molding such as in-mold molding, the transfer sheet including the colored layer and the functional layer B and the injected resin forming the core layer are tightly attached to each other under high pressure within the mold, making it easy to achieve the above configuration. Furthermore, in injection molding such as in-mold molding, the transfer sheet including the colored layer and the functional layer B is brought into close contact with the high-temperature injected resin that forms the core layer under high pressure, which causes a portion of the colored layer and a portion of the core layer to melt and become integrated at the interface between the colored layer and the core layer. In this way, the adhesion at the interface between the colored layer and the core layer is easily improved, and a stronger surface protection plate can be produced. Even when a transfer sheet including a colored layer and functional layer B is used, it is difficult to achieve the above configuration by methods other than injection molding such as in-mold molding. For example, in a method in which a transfer sheet including a colored layer and functional layer B is placed on a pre-formed core layer, a heated roll is pressed against the core layer to bring the core layer and the transfer sheet into close contact, and then the release sheet of the transfer sheet is peeled off, the colored layer hardly sinks into the core layer, making it difficult to achieve the above configuration.

[0019] In this specification, "the position of the surface of the colored layer facing the functional layer B and the position of the surface of the core layer facing the functional layer B in the region without the colored layer are substantially the same in the thickness direction of the surface protection plate" means that when a cross section of the surface protection plate cut vertically is imaged using an SEM or the like, the difference in height between the position of the surface of the colored layer facing the functional layer B and the position of the surface of the core layer facing the functional layer B in the region without the colored layer is 1.0 μm or less, preferably 0.5 μm or less, and more preferably 0.2 μm or less. If the surface protection plate has a curved shape, the above-mentioned difference in height is determined based on the curved surface.

[0020] In one embodiment of the surface protection plate of the present invention, the thickness ratio of the core layer to the colored layer in the thickness direction of the surface protection plate (core layer thickness / colored layer thickness) is preferably at least 100, more preferably at least 200, even more preferably at least 500, and particularly preferably at least 1000. When the thickness ratio is at least 100, the transfer sheet including the colored layer and functional layer B and the injected resin that forms the core layer are easily adhered to each other under high pressure during injection molding, which makes it easier to substantially eliminate the gradient of the boundary between the region having the colored layer and the region not having the colored layer on the outermost surface on the rear side of the surface protection plate. The upper limit of the thickness ratio is not particularly limited, but is usually preferably 20,000 or less, and more preferably 10,000 or less.

[0021] In one embodiment of the surface protection plate of the present invention, the average inclination angle of the boundary between the area having the colored layer and the area not having the colored layer on the outermost surface on the back side of the surface protection plate is preferably 0.10 degrees or less, more preferably 0.07 degrees or less, even more preferably 0.05 degrees or less, and even more preferably 0.03 degrees or less. By setting the average tilt angle to 0.10 degrees or less, it is possible to further prevent a decrease in visibility and prevent air bubbles from being mixed in when a functional component including a plastic film is attached to the back surface of the surface protection plate.

[0022] In this specification, the average tilt angle is calculated by the following (1) to (3). If the surface protection plate has a curved shape, the calculation of the average tilt angle in the following (1) to (3) is performed with a correction using a least-squares function. The average tilt angle can be measured, for example, with a white light interferometer-type surface profiler. (1) The surface shape of the back surface of the surface protection plate is measured. The surface shape measurement area is an area of at least 200 μm square, including at least the boundary between the area with the colored layer and the area without the colored layer. The surface shape measured here is the three-dimensional shape of an area of at least 200 μm square. (2) From the surface shape measured in (1) (the three-dimensional shape of an area of 200 μm square or more), 20 cross-sectional profiles with a width of 100 μm are obtained, centered on the boundary between the area with the colored layer and the area without the colored layer (BL in Figures 1 and 2). In Figures 1 and 2, the cross-sectional profile means a cross-sectional profile in the XZ direction. (3) The average inclination angle is calculated from each cross-sectional profile, and the average of the 18 average inclination angles obtained by discarding the maximum and minimum values is taken as the average inclination angle of the boundary of each surface protection plate.

[0023] In one embodiment of the surface protection plate of the present invention, the average difference (PV) between the maximum and minimum elevation values of the cross-sectional profile of the boundary between the area having the colored layer and the area not having the colored layer on the outermost surface on the back side of the surface protection plate is preferably 1.0 μm or less, more preferably 0.7 μm or less, even more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. By setting the average PV to 1.0 μm or less, it is possible to further prevent a decrease in visibility and prevent air bubbles from being mixed in when a functional component containing a plastic film is attached to the back surface of the surface protection plate.

[0024] The average PV can be calculated using substantially the same method as the average tilt angle. Specifically, the average PV can be calculated using the average tilt angle calculation methods (1) and (2) and the following (3'). Note that if the surface protection plate has a curved shape, correction using a least-squares function is performed. (3') From each cross-sectional profile, calculate the difference between the maximum and minimum elevation values (PV), and the average of the PVs at 18 locations, with the maximum and minimum values discarded, is used as the average PV at the boundary of each surface protection plate.

[0025] In one embodiment of the surface protection plate of the present invention, from the viewpoint of making it easier to impart hiding properties with the colored layer, the total light transmittance of the area having the colored layer is preferably 2% or less, more preferably 0.5% or less, even more preferably 0.04% or less, and even more preferably 0.0008% or less.

[0026] In one embodiment of the surface protection plate of the present invention, from the viewpoint of making the back surface of the surface protection plate easily visible, the total light transmittance of the area not having the colored layer is preferably 50% or more, more preferably 80% or more, and even more preferably 90% or more.

[0027] In this specification, the total light transmittance means the total light transmittance defined in JIS K7361-1:1997, and is the average value when measured at 20 locations.

[0028] In one embodiment of the surface protection plate of the present invention, when the pencil hardness on the front side (functional layer A side) is defined as PA and the pencil hardness on the back side (functional layer B side) is defined as PB, it is preferable that the relationship PA>PB is satisfied. By satisfying the relationship PA>PB, it is easier to improve the scratch resistance on the front side (functional layer A side), where scratch resistance is important, while it is easier to improve the adhesion between the layer adjacent to functional layer B on the back side (functional layer B side).

[0029] The pencil hardness of the front side (functional layer A side) is preferably H or higher, more preferably 2H or higher, and even more preferably 3H or higher. The pencil hardness of the back side (functional layer B side) is preferably 3B to 2H, and more preferably 2B to H. In this specification, the pencil hardness is based on the highest hardness that does not cause scratches when a pencil hardness test (4.9 N load) according to JIS K5600-5-4:1999 is carried out.

[0030] The reflectance of the front surface of the surface protection plate of the present invention is preferably lower than that of the rear surface. By making the reflectance of the front surface of the surface protection plate lower than that of the rear surface, reflection on the surface of the surface protection plate can be more easily suppressed. In this specification, reflectance refers to the luminous reflectance Y value. When measuring reflectance, a sample is prepared by attaching a black plate to the surface of the surface protection plate opposite to the surface to be measured via a transparent adhesive layer, and measurement is performed by irradiating light from the surface to be measured onto the sample at an incident angle of 5°. The light source used when measuring reflectance is preferably D65. The difference in refractive index between the transparent adhesive layer and a member (e.g., hard coat layer B) in contact with the sample's transparent adhesive layer is preferably within 0.15, more preferably within 0.10, and even more preferably within 0.05. The black plate preferably has a total light transmittance of 1% or less, more preferably 0%, according to JIS K7361-1:1997. The difference in refractive index between the resin constituting the black plate and the transparent adhesive layer is preferably within 0.15, more preferably within 0.10, and even more preferably within 0.05.

[0031] <Core layer> The core layer is mainly composed of a resin, which means that the resin accounts for 50% by mass or more of the total solid content constituting the core layer, preferably 70% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 99% by mass or more.

[0032] The resin for the core layer is preferably a thermoplastic resin from the viewpoint of ease of injection molding such as in-mold molding. By using a thermoplastic resin for the core layer, the resin for the core layer can be injected at high temperature and pressure during injection molding such as in-mold molding, which makes it easier to adhere the transfer sheet including the colored layer and functional layer B to the resin for the core layer, and also makes it easier for a part of the colored layer and a part of the core layer to melt and integrate at the interface between the colored layer and the core layer. In this way, the part of the colored layer and a part of the core layer can more easily integrate at the interface between the colored layer and the core layer, which makes it easier to improve adhesion at the interface between the colored layer and the core layer, and a stronger surface protection plate can be produced. Examples of thermoplastic resins include polystyrene resins, polyolefin resins, ABS resins, AS resins, AN resins, polyphenylene oxide resins, polycarbonate resins, polyacetal resins, acrylic resins, polyethylene terephthalate resins, polybutylene terephthalate resins, polysulfone resins, and polyphenylene sulfide resins, and mixtures thereof. Among these, polycarbonate resins and acrylic resins are preferred, and polycarbonate resins, which have excellent impact resistance, are more preferred.

[0033] The in-plane retardation of the core layer at a wavelength of 589 nm is preferably 300 nm or less, more preferably 200 nm or less. By setting the in-plane retardation within this range, it is possible to prevent rainbow-like irregularities from being visible when the screen of a liquid crystal display device or the like is observed through a surface protection plate and polarized sunglasses. The in-plane retardation (Re) is expressed by the following formula (1), where nx is the refractive index in the direction with the largest refractive index in the plane of the core layer (slow axis direction), ny is the refractive index in the direction perpendicular to the slow axis direction (fast axis direction), and d is the thickness of the core layer (nm). Re = (nx - ny) × d (1) The in-plane retardation can be measured, for example, by KOBRA-WR manufactured by Oji Scientific Instruments.

[0034] In order to set the in-plane retardation of the core layer within the above range, it is preferable to use a resin that is less likely to cause retardation or to prevent the resin molecules from being oriented in a specific direction in the core layer.When a polycarbonate-based resin is used as the resin for the core layer and the polycarbonate-based resin is injection-molded, it is preferable to prevent the flow of the molten polycarbonate-based resin in the mold from being biased in a specific direction.

[0035] The core layer may contain additives such as ultraviolet absorbers, light stabilizers, antioxidants, and flame retardants, as needed.

[0036] The thickness of the core layer is not particularly limited, but is usually 1 mm or more, and preferably 1 to 10 mm. In this specification, the thickness of each layer (core layer, colored layer, etc.) constituting the surface protection plate is calculated as the average value of 20 arbitrary points when observing a vertical cross section of the surface protection plate using an electron microscope or the like.

[0037] <Colored layer> The surface protection plate of the present invention has a colored layer on a part of the surface of the core layer on the side of functional layer B. As described above, by having a colored layer on the side of functional layer B of the core layer (in other words, on the back side of the core layer), a sense of luxury based on a sense of depth can be imparted.

[0038] The colored layer preferably contains a binder resin and a colorant. The binder resin of the colored layer is preferably a thermoplastic resin from the viewpoint of improving adhesion between the core layer and the functional layer B. Examples of the thermoplastic resin as the binder resin of the colored layer include the same thermoplastic resins as those exemplified as the thermoplastic resin of the core layer. The colorant for the colored layer may be a general-purpose pigment or dye, and from the viewpoint of improving hiding power, a pigment is preferred. The blending ratio of the binder resin and the colorant may be adjusted appropriately in consideration of the balance between the coating strength and hiding power of the colored layer.

[0039] The colored layer may have any pattern, including solid printing or any other pattern such as letters, numbers, circles, ellipses, squares, polygons, geometric patterns, wood grain, pebble, cloth grain, and sand grain. Alternatively, portions of the solid printing may be cut out to display any pattern, such as letters, numbers, circles, ellipses, squares, polygons, and geometric patterns. The colored layer may be patterned to cover all or part of the edge of the surface protection plate when viewed from above, and is preferably patterned to cover the entire edge. Figure 5 is a perspective plan view of a surface protection plate with a colored layer 30 formed on the entire edge. The width of the edge is not particularly limited, but is typically about 1 to 20 mm, preferably 2 to 10 mm. The color of the colored layer is arbitrary, but dark colors such as black and brown are preferred.

[0040] The area ratio of the colored layer to the total area of the surface protection plate is not particularly limited and may be adjusted appropriately depending on the purpose. In many cases, the area ratio is about 20 to 80%.

[0041] From the viewpoint of the balance between hiding power and thinning of the surface protection plate, the thickness (T1) of the colored layer is preferably 0.5 to 10 μm, more preferably 1 to 5 μm, and even more preferably 2 to 4 μm.

[0042] The average thickness (T1) of the entire colored layer and the average thickness (T2) of the region 100 μm from the edge of the colored layer preferably satisfy 0.85≦T2 / T1≦1.00, more preferably 0.90≦T2 / T1≦1.00, and even more preferably 0.95≦T2 / T1≦1.00. By setting T2 / T1 in the above range, the edge of the colored layer becomes sharp, and it is easy to improve the design. Note that when T2 / T1 is set in the above range, it is disadvantageous in terms of visibility when a functional member including a plastic film is attached to the back surface of the surface protection plate, but by adopting the configuration of the surface protection plate of the present invention, preferably the configuration of a preferred embodiment of the surface protection plate of the present invention, it is easy to suppress the decrease in visibility.

[0043] In order to set T2 / T1 within the above range, it is preferable to "transfer the colored layer to the core layer using a transfer sheet containing the colored layer" and "form the colored layer by melt-thermal transfer of a solid colored layer (e.g., an ink ribbon) when forming the colored layer on a part of functional layer B of the transfer sheet." Note that when the colored layer is formed by a coating method, the edges of the colored layer become gentle, making it difficult to set T2 / T1 within the above range.

[0044] <Functional layer> The surface protection plate of the present invention has a functional layer A on the surface side of the core layer and a functional layer B on the back side of the core layer. Each of the functional layer A and the functional layer B may have a single-layer structure or a multi-layer structure. In the following, unless otherwise specified, the term "functional layer" refers to both functional layer A and functional layer B.

[0045] The functional layer A and the functional layer B may have the same configuration or different configurations, but preferably have different configurations. That is, it is preferable that the functional layer B has different layers from the functional layer A. Examples of "different layers" include layers with different resin compositions, layers with different surface shapes, layers with different thicknesses, etc. To make the functional layer A and the functional layer B have different structures, injection molding such as double-sided simultaneous in-mold molding, which will be described later, is effective.

[0046] The functional layer A preferably has a hard coat layer A from the viewpoint of the scratch resistance of the surface. Similarly, from the viewpoint of scratch resistance on the back surface, it is preferable that the functional layer B has a hard coat layer B. Incidentally, by having the hard coat layer B, the functional layer B functions as a barrier layer, which is preferable in that it can suppress the diffusion of components generated from the core layer and / or adhesive layer (an adhesive layer used when bonding a functional member including a plastic film to the back surface of a surface protection plate). Incidentally, components generated from the core layer and adhesive layer include low molecular weight components contained in these layers and gases resulting from residual solvents.

[0047] When the arithmetic mean roughness of the surface of hard coat layer A is defined as Ra-A and the arithmetic mean roughness of the surface of hard coat layer B is defined as Ra-B, it is preferable that the relationship Ra-A>Ra-B is satisfied. By satisfying the relationship Ra-A>Ra-B, it is possible to easily impart antiglare properties with hard coat layer A, while also making it easier to prevent the unevenness of hard coat layer B from reducing the resolution of objects (items, images, etc.) observed through the surface protection plate. In this specification, Ra-A and Ra-B refer to the arithmetic mean roughness according to JIS B0601:1994 when the cutoff value λc is 0.8 mm. Furthermore, Ra-A and Ra-B refer to the average of the arithmetic mean roughnesses at 18 points obtained by rounding down the maximum and minimum values from 20 arbitrary measurement points. Note that Ra-B is measured in an area that does not have a colored layer when the surface protection plate is viewed in plan.

[0048] Ra-A is preferably 0.01 to 10 μm, more preferably 0.01 to 0.149 μm, and even more preferably 0.01 to 0.114 μm. Furthermore, Ra-B is preferably 0.1 μm or less, more preferably 0.03 μm or less, and even more preferably 0.01 μm or less.

[0049] When the average spacing between the irregularities on the surface of the hard coat layer A is defined as Sm-A, it is preferable that Ra-A and Sm-A satisfy the following formulae (A1) and (A2). Ra-A[μm]×Sm-A[μm]≦5.00 (A1) 0.050[μm]≦Ra-A (A2)

[0050] In this specification, Sm-A refers to the average spacing of irregularities according to JIS B0601:1994 when the cutoff value λc is set to 0.8 mm. Sm-A also refers to the average of the average spacing of irregularities at 18 locations obtained by discarding the maximum and minimum values from measurements taken at any 20 locations.

[0051] The surface irregularities of the hard coat layer A correspond to lenses for the pixels of a display element. As a result of extensive research, the inventors have found that a large arithmetic mean roughness Ra tends to increase the thickness of the irregularities (i.e., the lens thickness) and worsen glare (a phenomenon in which minute variations in brightness are visible in image light), and that a large average spacing Sm of the irregularities tends to increase the spacing between the irregularities (i.e., the lens diameter) and worsen glare. Further research by the inventors has found that, although adjusting Ra and Sm alone is not enough to improve glare, adjusting the product of Ra and Sm can improve glare when a surface protection plate is used on the front surface of a display element such as a liquid crystal display element.

[0052] A Ra-A×Sm-A ratio of 5.00 or less means that the thickness of the lens formed by the concave-convex surfaces is small and / or the diameter of the lens formed by the concave-convex surfaces is small. Therefore, by satisfying formula (A1), glare can be easily suppressed. Ra-A×Sm-A is preferably 4.80 or less, more preferably 4.30 or less, and even more preferably 4.00 or less. The lower limit of Ra-A×Sm-A is not particularly limited, but is preferably 2.00 or more, more preferably 2.50 or more, and even more preferably 3.00 or more. The unit of Ra-A×Sm-A is [μm 2 ].

[0053] When Ra-A is 0.050 μm or more and formula (A2) is satisfied, good antiglare properties can be achieved. If Ra-A is too large, the thickness of the lens formed by the unevenness increases, which tends to worsen glare and reduce image clarity. For this reason, Ra-A is preferably 0.060 to 0.300 μm, more preferably 0.070 to 0.200 μm, and even more preferably 0.080 to 0.130 μm.

[0054] As long as the above formula (A1) is satisfied, the range of Sm-A is not particularly limited, but is preferably 10 to 100 μm, more preferably 20 to 80 μm, and even more preferably 30 to 70 μm.

[0055] When the ten-point average roughness of the surface of the hard coat layer A is defined as Rz-A, it is preferable that Ra-A and Rz-A satisfy the following formula (A3). Rz-A / Ra-A≦15.0 (A3)

[0056] Rz-A / Ra-A can be said to be a parameter indicating the randomness of the surface shape of the hard coat layer A. When Rz-A / Ra-A is 15.0 or less and formula (A3) is satisfied, glare can be easily suppressed. Rz-A / Ra-A is preferably 14.0 or less, more preferably 13.0 or less, and even more preferably 12.0 or less. The lower limit of Rz-A / Ra-A is preferably 5.0 or more, more preferably 6.0 or more, and even more preferably 7.0 or more, from the viewpoint that a certain degree of randomness can be imparted to the surface shape of the hard coat layer A and defects in the hard coat layer A can be made less noticeable.

[0057] Rz-A is preferably 0.25 to 5.00 μm, more preferably 0.50 to 2.50 μm, and even more preferably 1.00 to 2.00 μm. By setting Rz-A to 0.25 μm or more, defects in the hard coat layer A can be made less noticeable, improving yield. Furthermore, by setting Rz-A to 5.00 μm or less, whitening and glare can be suppressed when the surface protection plate is used on the front surface of a display element such as a liquid crystal display element.

[0058] When the pencil hardness of the hard coat layer A is defined as Ha-A and the pencil hardness of the hard coat layer B is defined as Ha-B, it is preferable that the relationship Ha-A>Ha-B is satisfied. By satisfying the relationship Ha-A>Ha-B, the scratch resistance of the hard coat layer A on the front side, where scratch resistance is important, can be easily improved, while the adhesion of the hard coat layer B on the back side to the layer adjacent to the hard coat layer B can be easily improved.

[0059] The pencil hardness of the hard coat layer A is preferably H or higher, more preferably 2H or higher, and even more preferably 3H or higher. The pencil hardness of the hard coat layer B is preferably 3B to 2H, and more preferably 2B to H. In this specification, the pencil hardness is based on the highest hardness that does not cause scratches when a pencil hardness test (4.9 N load) according to JIS K5600-5-4:1999 is carried out.

[0060] The hard coat layer A is formed from an electron beam curable resin composition described later. On the other hand, the hard coat layer B is preferably formed from an ultraviolet curable resin composition, which will be described later. By forming the hard coat layer A from an electron beam curable resin composition, it is possible to improve the scratch resistance of the hard coat layer A, and it is also possible to easily add an ultraviolet absorber to the hard coat layer A, which makes it possible to improve the weather resistance of the surface protection plate. Furthermore, by forming the hard coat layer B from an ultraviolet-curable resin composition, it is possible to easily improve the adhesion between the hard coat layer B and the adjacent layer.

[0061] <<Example of layer structure of functional layer A>> Examples of the layer configuration of the functional layer A include the following A1 to A6. In the following A1 to A6, " / " indicates the layer interface, and the layer located on the left side indicates the layer located on the core layer side. (A1) Adhesive layer A / Hard coat layer A (A2) Adhesive layer A / Anchor layer A / Hard coat layer A (A3) Adhesive layer A / Hard coat layer A / Anti-reflection layer A (A4) Adhesive layer A / Anchor layer A / Hard coat layer A / Anti-reflection layer A (A5) Hard Coat Layer A (A6) Hard coat layer A / anti-reflection layer A

[0062] <<Example of layer structure of functional layer B>> Examples of the layer configuration of the functional layer B include the following B1 to B6. In the following B1 to B6, " / " indicates the layer interface, and the layer located on the left side indicates the layer located on the core layer side. (B1) Adhesive layer B / Hard coat layer B (B2) Adhesive layer B / Anchor layer B / Hard coat layer B (B3) Adhesive layer B / Hard coat layer B / Anti-reflection layer B (B4) Adhesive layer B / Anchor layer B / Hard coat layer B / Anti-reflection layer B (B5) Hard Coat Layer B (B6) Hard coat layer B / anti-reflection layer B

[0063] The hard coat layers A of A1, A2 and A5 are preferably hard coat layers having antiglare properties (hard coat layers having an arithmetic mean roughness Ra-A in the above range). The hard coat layers A of A3, A4 and A6 and the hard coat layers B of B1 to B6 are preferably hard coat layers having a relatively smooth surface (hard coat layers having an arithmetic mean roughness in the above Ra-B range).

[0064] -Adhesive layer- The surface of the functional layer A that comes into contact with the core layer may have an adhesive layer A to improve adhesion to the core layer. From the same viewpoint, the surface of the functional layer B that comes into contact with the core layer may have an adhesive layer B. Furthermore, the film layer described below may have an adhesive layer on the surface that comes into contact with the core layer in order to improve adhesion to the core layer. In the following description, unless otherwise specified, the term "adhesive layer" refers to both adhesive layer A and adhesive layer B.

[0065] The adhesive layer may be a pressure-sensitive adhesive layer (a so-called "sticky layer") or a heat-sensitive adhesive layer (a so-called "heat seal layer"). When in-mold molding, which will be described later, is performed, the adhesive layer is preferably a heat-sensitive adhesive layer.

[0066] The adhesive layer preferably uses a heat-sensitive or pressure-sensitive resin that is suitable for the material of the core layer. For example, when the material of the core layer is an acrylic resin, it is preferable to use an acrylic resin. When the material of the core layer is a polyphenylene oxide resin, a polycarbonate resin, or a styrene resin, it is preferable to use an acrylic resin, a polystyrene resin, a polyamide resin, or the like that has affinity with these resins. Furthermore, when the material of the core layer is a polypropylene resin, it is preferable to use a chlorinated polyolefin resin, a chlorinated ethylene-vinyl acetate copolymer resin, a cyclized rubber, or a coumarone-indene resin.

[0067] The thickness of the adhesive layer is preferably 0.1 to 50 μm, and more preferably 0.5 to 30 μm.

[0068] -Hard coat layer- The hard coat layer A and the hard coat layer B preferably contain a cured product of a curable resin composition such as a thermosetting resin composition or an ionizing radiation-curable resin composition, and more preferably contain a cured product of an ionizing radiation-curable resin composition from the viewpoint of improving scratch resistance. Representative examples of ionizing radiation-curable resin compositions include ultraviolet-curable resin compositions and electron beam-curable resin compositions. Electron beam-curable resin compositions have the advantages of not requiring an initiator and being easily cured instantly to form a dense, hard film. Hereinafter, unless otherwise specified, the term "hard coat layer" refers to both hard coat layer A and hard coat layer B.

[0069] The thermosetting resin composition is a composition that contains at least a thermosetting resin and is a resin composition that is cured by heating. Examples of thermosetting resins include acrylic resins, urethane resins, phenolic resins, urea melamine resins, epoxy resins, unsaturated polyester resins, silicone resins, etc. In the thermosetting resin composition, a curing agent is added to the curable resin as needed.

[0070] The ionizing radiation-curable resin composition is a composition containing a compound having an ionizing radiation-curable functional group (hereinafter also referred to as "ionizing radiation-curable compound"). Examples of the ionizing radiation-curable functional group include ethylenically unsaturated bond groups such as (meth)acryloyl groups, vinyl groups, and allyl groups, as well as epoxy groups and oxetanyl groups. As the ionizing radiation-curable compound, a compound having an ethylenically unsaturated bond group is preferred, and a compound having two or more ethylenically unsaturated bond groups is more preferred. Among these, a polyfunctional (meth)acrylate compound having two or more ethylenically unsaturated bond groups is even more preferred. As the polyfunctional (meth)acrylate compound, either a monomer or an oligomer can be used. Ionizing radiation refers to electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing or crosslinking molecules. Usually, ultraviolet (UV) rays or electron beams (EB) are used, but other types of radiation such as electromagnetic waves (X-rays and gamma rays), alpha rays, and charged particle beams (ion beams) can also be used. In this specification, (meth)acrylate means acrylate or methacrylate, (meth)acrylic acid means acrylic acid or methacrylic acid, and (meth)acryloyl group means acryloyl group or methacryloyl group.

[0071] Among the polyfunctional (meth)acrylate compounds, examples of bifunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, and 1,6-hexanediol diacrylate. Examples of trifunctional or higher (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and isocyanuric acid-modified tri(meth)acrylate. The (meth)acrylate monomer may have a part of its molecular skeleton modified, and those modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, etc. may also be used.

[0072] Furthermore, examples of the polyfunctional (meth)acrylate oligomer include acrylate polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate. Urethane (meth)acrylates can be obtained, for example, by reacting a polyhydric alcohol and an organic diisocyanate with a hydroxy (meth)acrylate. In addition, preferred epoxy (meth)acrylates are (meth)acrylates obtained by reacting a tri- or higher functional aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with (meth)acrylic acid; (meth)acrylates obtained by reacting a di- or higher functional aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with a polybasic acid and (meth)acrylic acid; and (meth)acrylates obtained by reacting a di- or higher functional aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with a phenol and (meth)acrylic acid. The above ionizing radiation curable compounds can be used alone or in combination of two or more.

[0073] When the ionizing radiation curable compound is an ultraviolet ray curable compound, the ionizing radiation curable composition preferably contains additives such as a photopolymerization initiator and a photopolymerization accelerator. The photopolymerization initiator may be one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzil dimethyl ketal, benzoyl benzoate, α-acyloxime ester, thioxanthones, and the like. The photopolymerization accelerator can reduce polymerization inhibition caused by air during curing and increase the curing rate, and examples thereof include one or more selected from p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, etc.

[0074] The thickness of the hard coat layer is preferably 0.1 to 100 μm, more preferably 0.5 to 20 μm, and even more preferably 1 to 10 μm. By setting the thickness of the hard coat layer within the above range, it is possible to improve scratch resistance and easily suppress the occurrence of cracks during molding.

[0075] -Anchor layer- The functional layer A may have an anchor layer A to improve heat resistance. From the same viewpoint, the functional layer B may have an anchor layer B. In the following description, unless otherwise specified, the term "anchor layer" refers to both anchor layer A and anchor layer B.

[0076] When in-mold molding, which will be described later, is used to form a functional layer on a core layer, the functional layer is exposed to high temperatures due to the injected resin that constitutes the core layer. For this reason, it is preferable that the functional layer has an anchor layer. The anchor coat layer is preferably located closer to the core layer. Note that, when the functional layer has the adhesive layer described above, it is preferable that the anchor layer be located on the side of the adhesive layer opposite the core layer, where it contacts the adhesive layer.

[0077] The anchor layer preferably contains a cured product of a curable resin composition. Examples of the curable resin composition include a thermosetting resin composition and an ionizing radiation curable resin composition. The embodiments of the thermosetting resin composition and ionizing radiation curable resin composition of the anchor layer are the same as those of the thermosetting resin composition and ionizing radiation curable resin composition of the hard coat layer. The thickness of the anchor layer is preferably 0.1 to 6 μm, and more preferably 0.5 to 5 μm.

[0078] -Anti-reflection layer- The functional layer A may have an antireflection layer A on the front side to suppress surface reflection, and the functional layer B may have an antireflection layer B on the back side to improve the light transmittance of the surface protection plate. Hereinafter, unless otherwise specified, the term "antireflection layer" refers to both antireflection layer A and antireflection layer B.

[0079] The antireflection layer may have, for example, a single-layer structure of a low refractive index layer or a two-layer structure of a high refractive index layer and a low refractive index layer. In the case of a two-layer structure of a high refractive index layer and a low refractive index layer, the high refractive index layer is disposed on the core layer side. The refractive index and thickness of the high refractive index layer and the low refractive index layer may be adjusted within a conventionally known range. Antireflection layers such as the high refractive index layer and the low refractive index layer can be roughly divided into those formed by a wet method and those formed by a dry method. When injection molding such as in-mold molding, which will be described later, is performed, the antireflection layer is preferably formed by a wet method from the viewpoint of preventing cracks during molding.

[0080] -Low refractive index layer- The refractive index of the low refractive index layer is preferably from 1.10 to 1.48, more preferably from 1.20 to 1.45, more preferably from 1.26 to 1.40, more preferably from 1.28 to 1.38, and still more preferably from 1.30 to 1.32.

[0081] The method for forming a low refractive index layer can be roughly divided into a wet method and a dry method. The wet method includes a method of forming a low refractive index layer by a sol-gel method using a metal alkoxide or the like, a method of forming a low refractive index layer by coating a resin having a low refractive index such as a fluororesin, and a method of forming a low refractive index layer by coating a coating liquid for forming a low refractive index layer in which low refractive index particles are contained in a resin composition. The dry method includes a method of selecting particles having a desired refractive index from the low refractive index particles described below and forming the layer by a physical vapor deposition method or a chemical vapor deposition method. The wet method is excellent in terms of production efficiency, and among the wet methods, it is preferable to form the layer using a coating liquid for forming a low refractive index layer in which low refractive index particles are contained in a binder resin composition.

[0082] The low refractive index particles can be any of particles made of inorganic compounds such as silica and magnesium fluoride, or particles made of organic compounds, but from the viewpoint of improving antireflection properties by lowering the refractive index, particles having a void structure are preferably used.Furthermore, from the viewpoint of improving the strength of the low refractive index layer, it is also preferable to use particles without voids (solid particles) in addition to particles having voids. Particles with a porous structure have minute voids inside, and because they are filled with a gas such as air with a refractive index of 1.0, they have a low refractive index. Examples of such void-containing particles include inorganic or organic porous particles and hollow particles, such as porous silica, hollow silica particles, or porous polymer particles and hollow polymer particles made from acrylic resins. Furthermore, inorganic compounds such as silica and magnesium fluoride are preferred as the material for particles without voids (solid particles). The average particle size of the primary particles of the low refractive index particles is preferably 50 to 100 nm, more preferably 60 to 80 nm, for particles having voids, and preferably 5 to 20 nm, more preferably 10 to 15 nm for particles without voids (solid particles).

[0083] The content of the low refractive index particles is preferably 50 to 400 parts by mass, more preferably 60 to 300 parts by mass, and more preferably 70 to 200 parts by mass for particles having voids, relative to 100 parts by mass of the binder component, and is preferably 70 to 250 parts by mass, more preferably 90 to 200 parts by mass, and more preferably 100 to 150 parts by mass for particles without voids (solid particles).

[0084] The binder resin composition is preferably a curable resin composition, which becomes a cured product in the antireflection layer and serves as a binder component. Examples of the curable resin composition include a heat-curable resin composition and an ionizing radiation-curable resin composition, and among these, an ionizing radiation-curable resin composition is preferred. The embodiments of the thermosetting resin composition and ionizing radiation curable resin composition of the binder resin composition of the low reflectivity layer are the same as those of the thermosetting resin composition and ionizing radiation curable resin composition of the hard coat layer.

[0085] -High refractive index layer- The antireflection layer may further include a high refractive index layer. By including a high refractive index layer in addition to a low refractive index layer, the wavelength range in which reflectance is low can be widened. The high refractive index layer is disposed closer to the core layer than the low refractive index layer.

[0086] The refractive index of the high refractive index layer is preferably from 1.53 to 1.85, more preferably from 1.54 to 1.80, more preferably from 1.55 to 1.75, and even more preferably from 1.56 to 1.70. The thickness of the high refractive index layer is preferably 200 nm or less, more preferably 50 to 180 nm, and even more preferably 70 to 150 nm.

[0087] The high refractive index layer can be formed from a coating liquid containing a binder resin composition and high refractive index particles. The binder resin composition can be, for example, the curable resin composition exemplified for the hard coat layer.

[0088] Examples of high refractive index particles include antimony pentoxide (1.79), zinc oxide (1.90), titanium oxide (2.3 to 2.7), cerium oxide (1.95), tin-doped indium oxide (1.95 to 2.00), antimony-doped tin oxide (1.75 to 1.85), yttrium oxide (1.87), and zirconium oxide (2.10). The average particle size of the primary particles of the high refractive index particles is preferably from 5 to 200 nm, more preferably from 5 to 100 nm, and even more preferably from 10 to 80 nm.

[0089] -Film layer- The surface protection plate of the present invention preferably has a film layer A between the core layer and the functional layer A. In addition, a film layer B may be present between the core layer and the functional layer B, but from the viewpoint of thinning, it is preferable not to have a film layer B between the core layer and the functional layer B. By having a film layer between the core layer and the functional layer (particularly by having film layer A between the core layer and functional layer A), it is possible to easily increase the pencil hardness of the surface of the surface protection plate, and to easily improve the scratch resistance of the surface protection plate.

[0090] Examples of the film layer include plastic films made of resins such as polyolefin resins such as polyethylene and polypropylene, vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer and ethylene-vinyl alcohol copolymer, polyester resins such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate, acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate, styrene resins such as polystyrene, and polyamide resins typified by nylon 6 or nylon 66. Among these plastic films, biaxially oriented polyester film is preferred from the viewpoints of heat resistance and dimensional stability, and acrylic film, polycarbonate film, or co-extruded product of acrylic and polycarbonate is preferred from the viewpoints of formability for insert molding etc. and weather resistance.

[0091] From the viewpoints of formability and handling, the thickness of the film layer is preferably 40 μm to 500 μm, more preferably 100 μm to 300 μm, and even more preferably 150 μm to 280 μm.

[0092] -Primer layer- The film layer A of the surface protection plate of the present invention preferably has a primer layer A on the surface of the film layer A that is in contact with the functional layer A. Furthermore, when the surface protection plate includes a film layer B, the film layer B preferably has a primer layer B on the surface of the film layer B that is in contact with the functional layer B. By providing a primer layer on the surface of the film layer that comes into contact with the functional layer, it is possible to more easily improve the adhesion between the film layer and the functional layer, and a stronger surface protection plate can be produced.

[0093] The primer layer preferably contains a thermoplastic resin or a cured product of a curable resin composition such as a thermosetting resin composition or an ionizing radiation curable resin composition. The thermoplastic resin for the primer layer may be the same as that exemplified as the thermoplastic resin for the core layer. The thermosetting resin composition and the ionizing radiation curable resin composition for the primer layer may be the same as those for the hard coat layer.

[0094] The thickness of the primer layer is preferably 0.1 to 10 μm, more preferably 0.2 to 5 μm, and even more preferably 0.3 to 3 μm.

[0095] [Method of manufacturing surface protection plate] The method for producing a surface protection plate of the present invention includes the following steps (1) and (2).

[0096] (1) A process of placing a laminate A having a functional layer A on one side of a pair of injection molding molds, and placing a laminate B having a functional layer B and a colored layer on a portion of the functional layer B on the other side of the molds. (2) A step of clamping the mold, injecting an injection resin into the mold, and obtaining a laminate X in which the laminate A, a core layer containing the injected resin, and the laminate B are tightly adhered together.

[0097] Examples of combinations of the laminate A and the laminate B disposed one above the other in step (1) include the following patterns (Z1) to (Z4). (Z1) Laminate A: Transfer sheet A having functional layer A on a release sheet, Laminate B: Transfer sheet B having functional layer B on a release sheet (Z2) Laminate A: Laminated film A in which film layer A and functional layer A are laminated, Laminate B: Transfer sheet B in which functional layer B is provided on a release sheet (Z3) Laminate A: Transfer sheet A having functional layer A on a release sheet, Laminate B: Laminated film B having film layer B and functional layer B laminated together (Z4) Laminate A: Laminated film A in which film layer A and functional layer A are laminated, Laminate B: Laminated film B in which film layer B and functional layer B are laminated

[0098] In step (1), when a transfer sheet is used for laminate A or laminate B, the transfer sheet is brought into contact with the mold so that the surface of the transfer sheet opposite the release sheet faces the gap (the side that comes into contact with the injected resin) formed by a pair of molds (male and female) that make up the injection molding mold.

[0099] Injection molding in which either laminate A or laminate B is a transfer sheet is known as "in-mold molding." Injection molding in which both laminate A and laminate B are transfer sheets is known as "double in-mold molding." Injection molding in which either Laminate A or Laminate B is a laminate film is known as "insert molding." Injection molding in which both Laminate A and Laminate B are laminate films is known as "double insert molding." Injection molding in which one of laminate A and laminate B is a transfer sheet and the other is a laminate film is so-called "double insert in-mold molding."

[0100] The transfer sheet A used in step (1) can be obtained by sequentially forming each layer constituting the functional layer A on a release sheet. The transfer sheet B used in step (1) can be obtained by sequentially forming each layer constituting the functional layer B on a release sheet, and then forming a colored layer on a part of the functional layer B. From the viewpoint of achieving sharp edges, the colored layer is preferably formed by melt-thermal transfer of a solid colored layer (e.g., an ink ribbon).

[0101] When the functional layer of the transfer sheet has a hard coat layer, the surface shape of the hard coat layer is similar to the inverse of the surface shape of the release sheet. That is, the surface shapes of the hard coat layer A and the hard coat layer B can be adjusted by the surface shape of the release sheet.

[0102] In addition, in step (1), when a laminate film is used for laminate A or B, the laminate film is abutted against the mold so that the side of the laminate film opposite the functional layer faces the void side (the side that comes into contact with the injected resin) formed by a pair of molds (male and female) that make up the molding mold.

[0103] The laminated film A used in step (1) can be obtained by sequentially forming each layer constituting the functional layer A on the film layer A. In addition, when a primer layer is provided between the film layer A and the functional layer A, the primer layer may be formed on the surface of the film layer A that comes into contact with the functional layer A before the functional layer A is formed on the film layer A.

[0104] When the functional layers of the laminate A and the laminate B have a hard coat layer, it is preferable that the hard coat layer is semi-cured at the stage of the transfer sheet, and that the hard coat layer is cured by irradiating it with ultraviolet light after molding the laminate X. By using such a method, it is possible to easily improve moldability.

[0105] The resin injected in step (2) is preferably a thermoplastic resin, such as a polystyrene resin, a polyolefin resin, an ABS resin (including heat-resistant ABS resin), an AS resin, an AN resin, a polyphenylene oxide resin, a polycarbonate resin, a polyacetal resin, an acrylic resin, a polyethylene terephthalate resin, a polybutylene terephthalate resin, a polysulfone resin, or a polyphenylene sulfide resin, or a mixture thereof.

[0106] In step (2), when injecting the resin into the injection mold, it is preferable to adjust the temperature, pressure, and speed of the injected resin to ensure good adhesion, taking into consideration the material of the layers that come into direct contact with the injected resin (the functional layer located on the core layer side, and the colored layer or film layer).

[0107] When the laminate A and the laminate B have a release sheet, the method for producing a surface protection plate of the present invention preferably further includes the following step (3). (3) A step of opening the mold and peeling off the release sheet of the transfer sheet from the laminate X. In step (3), in order to prevent foil tearing or transfer failure of the functional layer when peeling off the release sheet, it is preferable to select a combination of the material of the core layer and the material of the functional layer, or to adjust the thickness of the functional layer.

[0108] [Laminated member] The laminated member of the present invention is obtained by laminating a functional member having at least one plastic film on the back side of a surface protection plate via an adhesive layer.

[0109] The surface protection plate constituting the laminated member of the present invention has a suppressed gradient at the boundary between the region having a colored layer and the region not having a colored layer on the outermost surface on the back side. Therefore, the laminated member of the present invention, in which a functional member is attached to the back side of the surface protection plate, can make it difficult for the optical axis of the plastic film of the functional member to change, and can suppress a decrease in visibility.

[0110] <Adhesive layer> The adhesive layer can be formed from a general-purpose adhesive, but is preferably a so-called transparent optical adhesive (OCA). Acrylic resins are preferably used for the transparent optical adhesive layer in terms of optical properties, light resistance, weather resistance, heat resistance, and transparency. Examples of monomers constituting the acrylic resin include alkyl acrylate esters such as ethyl acrylate, butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, cyclohexyl acrylate, and benzyl acrylate, and alkyl methacrylate esters such as ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate. In addition to the above-mentioned monomers, vinyl group-containing compounds such as vinyl acetate, vinyl propionate, vinyl ether, styrene, acrylonitrile, and methacrylonitrile may also be used as copolymerization monomers for the monomers constituting the acrylic resin.

[0111] The thickness of the adhesive layer is preferably 0.1 to 50 μm, and more preferably 0.5 to 30 μm.

[0112] In one embodiment of the laminated member of the present invention, it is preferable that no glass is provided between the plastic film located closest to the surface protection plate side of the functional member and the adhesive layer. By having such a configuration of the laminated member, the effects of the present invention can be easily exhibited.

[0113] <Functional materials> The functional member having at least one plastic film may be a single layer of plastic film, or may be a functional member (for example, a touch panel) having a member other than a plastic film. Examples of touch panels including a plastic film include capacitive touch panels, resistive touch panels, optical touch panels, ultrasonic touch panels, and electromagnetic induction touch panels.

[0114] <<Plastic film>> Examples of plastic films included in the functional member include those formed from resins such as polyester, triacetyl cellulose (TAC), cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyethersulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polymethyl methacrylate, polycarbonate, polyurethane, and amorphous olefin (Cyclo-Olefin-Polymer: COP). Among these plastic films, stretched plastic films are prone to affecting visibility due to changes in the optical axis. Therefore, when the plastic film contains a stretched plastic film, the effects based on the configuration of the present invention are more pronounced, which is preferable. In particular, stretched polyester films (especially uniaxially stretched polyester films among stretched polyester films) have a high in-plane retardation value, and partial changes in the optical axis tend to change the in-plane retardation of the relevant part, so the effects based on the configuration of the present invention are more likely to be exerted.

[0115] The in-plane retardation of the plastic film at a wavelength of 589 nm is preferably 3000 nm to 30000 nm, more preferably 5000 nm to 20000 nm, and further preferably 7000 nm to 15000 nm. The in-plane retardation (Re) of a plastic film is expressed by the above formula (1), where nx is the refractive index in the direction with the highest refractive index in the plane of the plastic film (slow axis direction), ny is the refractive index in the direction perpendicular to the slow axis direction (fast axis direction), and d is the thickness of the plastic film (nm). The in-plane retardation can be measured, for example, by KOBRA-WR manufactured by Oji Scientific Instruments.

[0116] The thickness of the plastic film is preferably 5 to 200 μm, and more preferably 10 to 150 μm.

[0117] [Image display device] The image display device of the present invention comprises the above-described laminated member of the present invention on a display element, and is arranged so that the surface of the laminated member on the functional member side faces the display element side.

[0118] Examples of the display element include a liquid crystal display element, an EL display element, a plasma display element, and an electronic paper element. [Example]

[0119] EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the embodiments described in the Examples.

[0120] 1. Measurement and evaluation The surface protection plates obtained in the examples and comparative examples were subjected to the following measurements and evaluations. The results are shown in Table 1.

[0121] 1-1. Surface shape of the boundary area [Surface shape measurement and analysis] The surface shape of the boundary between the area with a colored layer and the area without a colored layer on the outermost surface on the back side of the surface protection plates of the Examples and Comparative Examples was measured using a white light interference microscope (New View 6300, Zygo) under the following conditions: Measurements were performed using the Microscope Application in MetroPro ver. 8.1.5, and analysis was performed using the Microscope Application and Advanced Texture Application in MetroPro ver. 8.1.5. <Measurement conditions> Objective lens: x50 Image Zoom:×1 [Measurement Controls] Acquisition Mode:Scan Camera Mode: 992 x 992 50Hz Subtract Sys Err:Off AGC:On Phase Res:High Connection Order:Location Discon Action:Filter Min Mod(%): 0.001 Min Area Size:7 Image Zoom:×1 Remove Fringes:On Number of Averages: 0 FDA Noise Threshold: 10 Scan Length: 15um bipolar Extended Scan Length: 1000 μm FDA Res:High Camera resolution (spacing per point): 0.22 μm Measurement area: 216μm x 216μm [Surface Map Controls] Removed: None sphere Radius:0nm Trim:0 Trim Mode: All Data Fill:On Data Fill Max:500 Filter:Off FilterType:Gauss Spline Filter Window Size: 3 Filter Trim: On Filter Low Wavelen: 1100μm High Wavelength Filter: 200 μm Filter Low Freq: 0.90909 1 / mm Filter High Freq: 5.00000 1 / mm

[0122] [Calculation of average tilt angle and PV] From the surface shapes measured and analyzed as described above, 20 cross-sectional profiles with a width of 100 μm were obtained, and the average of the average inclination angles of 18 locations, with the maximum and minimum values discarded, was used as the average inclination angle of the boundary of the surface protection plate of the Example and Comparative Example. In addition, using the same cross-sectional profile as the cross-sectional profile from which the average inclination angle was calculated, the difference between the maximum and minimum elevation values (PV) was calculated from each cross-sectional profile, and the average of the PVs of the 18 locations, with the maximum and minimum values discarded, was used as the average PV of the boundary of the surface protection plate of the Example and Comparative Example.

[0123] 1-2.Total light transmittance The total light transmittance of the area with a colored layer and the area without a colored layer of the surface protection plate was measured according to JIS K7361-1:1997. The light incident surface was the functional layer B side. The measurement device used was a haze meter (model number: HM-150, manufactured by Murakami Color Research Laboratory).

[0124] 1-3. Arithmetic mean roughness of hard coat layer A and hard coat layer B For the surface protection plates obtained in the examples and comparative examples, the arithmetic mean roughness (Ra-A) of hard coat layer A and the arithmetic mean roughness (Ra-B) of hard coat layer B were measured in accordance with JIS B0601:2001. The cutoff value (λc) was set to 0.8 mm. The surface roughness measuring instrument used was an "ET-4000L" manufactured by Kosaka Laboratory Co., Ltd. The stylus and measurement conditions were as follows:

[0125] [Surface roughness detection stylus] Kosaka Laboratory's product name: ET1480 (tip curvature radius: 0.5 μm, material: diamond) [Surface roughness measuring instrument measurement conditions] Reference length (cutoff value λc of roughness curve): 0.8 mm Evaluation length (reference length (cutoff value λc) x 5): 4.0 mm Stylus feed speed: 0.1mm / s Reserve length: (Cutoff value λc) x 1 Vertical magnification: 10,000x ·Horizontal magnification: 100x Filter characteristics: Gaussian Leveling: None λs filter: None Sampling mode: c=1500

[0126] 1-4.Pencil hardness The pencil hardness was measured by conditioning the surface protection board for 2 hours at a temperature of 25°C and a relative humidity of 60%, and then using a test pencil specified in JIS-S-6006, a pencil hardness test (4.9 N load) specified in JIS K5600-5-4 (1999) was performed on the front side (functional layer A side) and back side (functional layer B side) of the surface protection board, and the highest pencil hardness that did not cause scratches was evaluated.

[0127] 1-5.Evaluation [Visibility] The plastic film side of the laminated members obtained in the examples and comparative examples was placed on the surface of an image display device (Apple's iPad (registered trademark) Air, resolution: 264 ppi), and a white image was displayed. An image near the boundary between the area with the colored layer and the area without the colored layer was compared with an image at a location away from the boundary, and the average score of 20 subjects was calculated, with 1 point given for images in which the color was perceived to be different, 2 points for images that could not be determined, and 3 points for images in which the color was not perceived to be different. The average score of 20 subjects was calculated and ranked according to the following criteria. <Rank> A: Average score of 2.5 or above B: Average score is 1.5 or more but less than 2.5 C: Average score is less than 1.5

[0128] 2. Preparation of Coating Solution The following coating solutions were prepared. Note that "parts" and "%" are by weight. <Coating liquid 1 for hard coat layer> Urethane acrylate UV-curable resin composition 100 parts (Solid content 35% by mass, toluene / ethyl acetate mixed solvent) <Coating liquid for heat-sensitive adhesive layer 1> Vinyl chloride-vinyl acetate copolymer (product name "ST-P A Varnish", manufactured by DNP Fine Chemicals Co., Ltd., solid content 30%) 100 parts by weight Dilution solvent (methyl ethyl ketone, toluene) appropriate amount <Coating liquid 1 for low refractive index layer> Photopolymerization initiator 0.1 parts by mass (Manufactured by IGM Resins, product name "Omnirad 127") ·UV curable resin 1.1 parts by mass (Tri- to tetrafunctional alkoxylated pentaerythritol acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., product name "NK Ester ATM-4PL") Hollow silica 6.3 parts by weight (active ingredient: 1.3 parts by weight) (Average particle size 60nm) Solid silica 0.9 parts by weight (active ingredient: 0.3 parts by weight) (Average particle size 12nm) Fluorine-based antifouling agent 0.1 parts by weight (active ingredient: 0.005 parts by weight) (DIC, product name "Megafac F-568") ·Dilution solvent 91.5 parts by mass (9:1 mixed solvent of methyl isobutyl ketone and propylene glycol monomethyl ether acetate)

[0129] 3. Preparation of transfer sheet [Transfer sheet 1] A release sheet 1 was prepared, which was made by forming a releasable uneven layer on a polyethylene terephthalate film having a thickness of 50 μm. Next, the hard coat coating solution 1 was applied to the surface of the release sheet 1 having the uneven layer so that the thickness after drying would be 5 μm, dried, and irradiated with ultraviolet light (irradiation dose 50 mJ / cm ). 2 ) to form a hard coat layer A. Next, the coating liquid 1 for heat-sensitive adhesive layer was applied onto the hard coat layer A so that the thickness after drying would be 2 μm, and then dried to form a heat-sensitive adhesive layer A, and a transfer sheet 1 was obtained.

[0130] [Transfer sheet 2] A polyethylene terephthalate film having a thickness of 50 μm and having releasability (release sheet 2, the surface having releasability was substantially smooth) was prepared. Next, the hard coat coating solution 1 was applied to the releasable surface of the release sheet 2 so that the thickness after drying would be 5 μm, dried, and irradiated with ultraviolet light (irradiation dose 50 mJ / cm 2 ) to form a hard coat layer B. Next, the coating liquid 1 for heat-sensitive adhesive layer was applied onto the hard coat layer B so that the thickness after drying would be 2 μm, and then dried to form a heat-sensitive adhesive layer B. Next, a black ink ribbon (total thickness 3 μm) was melt-transferred onto a part of the adhesive layer B to form a colored layer, and a transfer sheet 2 was obtained.

[0131] [Transfer sheet 3] Transfer sheet 3 was obtained in the same manner as transfer sheet 2, except that no colored layer was formed on adhesive layer B.

[0132] 4. Preparation of Laminated Film [Laminated film 1] Hard coat layer A was formed by applying hard coat coating liquid 1 onto an acrylic film having a thickness of 250 μm so that the thickness after drying would be 4 μm, followed by drying and irradiating with ultraviolet light. Next, coating liquid 1 for the low refractive index layer was applied onto hard coat layer A so that the thickness after drying would be 100 nm, followed by drying and ultraviolet irradiation to form antireflection layer A, which was a single layer of low refractive index layer, thereby obtaining laminated film 1 having film layer A (polyethylene terephthalate film), hard coat layer A, and antireflection layer A (single layer of low refractive index layer) in this order. The refractive index of the low refractive index layer formed from Coating Solution 1 for low refractive index layer was 1.30.

[0133] 5. Preparation of surface protection plate and laminated member [Example 1] Transfer sheet 1 prepared in "3" above was placed on one side of a pair of upper and lower in-mold molding dies, and transfer sheet 2 prepared in "3" above was placed on the other side of the dies. Transfer sheets 1 and 2 were placed so that the surface opposite to the release sheet faced the inside of the dies (the side in contact with the injected resin). Next, the mold was clamped and an injection resin (polycarbonate resin) was injected into the mold, resulting in a laminate X in which the surface of transfer sheet 1 opposite the release sheet, a core layer (thickness 2.0 mm) containing the injection resin, and the surface of transfer sheet 2 opposite the release sheet were tightly adhered together. Next, after the mold was opened, the release sheets of transfer sheet 1 and transfer sheet 2 were peeled off from laminate X. Next, ultraviolet irradiation (irradiation dose 800 mJ / cm 2 ) to promote the curing of the hard coat layers A and B, thereby obtaining a surface protection plate of Example 1. The surface protection plate of Example 1 had, from the front side to the back side, hard coat layer A (a hard coat layer having an uneven surface), adhesive layer A, core layer, colored layer (Note: the colored layer was formed partially, not entirely), adhesive layer B, and hard coat layer B, in this order. In addition, in the surface protection plate of Example 1, the position of the surface of the colored layer facing the functional layer B (adhesive layer B) and the position of the surface of the core layer facing the functional layer B (adhesive layer B) in the area not having the colored layer were substantially identical in the thickness direction of the surface protection plate.

[0134] Next, a plastic film (a uniaxially oriented polyester film manufactured by Toyobo Co., Ltd., product name "Cosmoshine", in-plane phase difference (internal retardation): 8400 nm) was laminated on the back side (hard coat layer B side) of the surface protection plate of Example 1 via an optical adhesive layer (manufactured by Panac Corporation, product name "Panaclean PD-S1", thickness 50 μm) to obtain the laminated member of Example 1.

[0135] [Example 2] The laminate film 1 prepared in "4" above was placed on one side of a pair of upper and lower injection molds, and the transfer sheet 2 prepared in "3" above was placed on the other side of the molds. The laminate film 1 was placed so that the surface on the film layer side faced the inside of the mold (the side that comes into contact with the injected resin). The transfer sheet 2 was placed so that the surface opposite the release sheet faced the inside of the mold (the side that comes into contact with the injected resin). Next, the mold was clamped and injected resin (polycarbonate resin) was injected into the mold, resulting in a laminate X in which the surface of the film layer A side of the laminated film 1, a core layer (thickness 2.0 mm) containing the injected resin, and the surface of the transfer sheet 2 opposite the release sheet were adhered together. Next, after the mold was opened, the release sheet of the transfer sheet 2 was peeled off from the laminate X. Next, ultraviolet irradiation (irradiation dose 800 mJ / cm 2 ) to promote the curing of the hard coat layers A and B, thereby obtaining a surface protection plate of Example 2. The surface protection plate of Example 2 had, from the front surface side to the back surface side, an antireflection layer A, a hard coat layer A, a film layer A, a core layer, a colored layer (Note: the colored layer was formed partially, not entirely), an adhesive layer B, and a hard coat layer B, in this order. In addition, in the surface protection plate of Example 2, the position of the surface of the colored layer facing the functional layer B (adhesive layer B) and the position of the surface of the core layer facing the functional layer B (adhesive layer B) in the area not having the colored layer were substantially identical in the thickness direction of the surface protection plate.

[0136] Next, a plastic film (a uniaxially oriented polyester film manufactured by Toyobo Co., Ltd., product name "Cosmoshine", in-plane phase difference (internal retardation): 8400 nm) was laminated on the back side (hard coat layer B side) of the surface protection plate of Example 2 via an optical adhesive layer (manufactured by Panac Corporation, product name "Panaclean PD-S1", thickness 50 μm) to obtain the laminated member of Example 2.

[0137] [Reference example 1] The laminated film 1 prepared in "4" above was placed on one side of a pair of upper and lower injection molds. The laminated film 1 was placed so that the surface on the film layer side faced the inside of the mold (the side that contacts the injected resin). Next, the mold was clamped, and an injection resin (polycarbonate resin) was injected into the mold, thereby obtaining a laminate Y in which the plastic film side of the laminate film 1 was adhered to a core layer (thickness 2.0 mm) containing the injection resin. Next, the mold was opened and the laminate Y was collected. Next, the surface of the adhesive layer B of the transfer sheet 2 prepared in "3" above was laminated to the exposed surface of the core layer of the laminate Y, and then the release sheet of the transfer sheet 2 was peeled off. Next, ultraviolet irradiation (irradiation dose 800 mJ / cm 2 ) to promote the curing of the hard coat layers A and B, thereby obtaining a surface protection plate of Example 2. The surface protection plate of Example 2 had, from the front surface side to the back surface side, an antireflection layer A, a hard coat layer A, a film layer A, a core layer, a colored layer (Note: the colored layer was formed partially, not entirely), an adhesive layer B, and a hard coat layer B, in this order. In addition, since the surface protection plate of Reference Example 1 was formed by laminating functional layer B, the position of the surface of the colored layer facing the functional layer B and the position of the surface of the core layer facing the functional layer B in the area not having the colored layer were not substantially identical in the thickness direction of the surface protection plate, and there was a slope at the boundary between the area having the colored layer and the area not having the colored layer on the outermost surface on the back side of the surface protection plate.

[0138] Next, a plastic film (a uniaxially oriented polyester film manufactured by Toyobo Co., Ltd., product name "Cosmoshine", in-plane phase difference (internal retardation): 8400 nm) was laminated on the back side (hard coat layer B side) of the surface protection plate of Reference Example 1 via an optical adhesive layer (manufactured by Panac Corporation, product name "Panaclean PD-S1", thickness 50 μm) to obtain the laminated member of Reference Example 1.

[0139] [Comparative Example 1] The transfer sheet 1 prepared in "3" above was placed on one side of a pair of upper and lower in-mold molding dies, and the transfer sheet 3 prepared in "3" above was placed on the other side of the dies. Transfer sheets 1 and 3 were placed so that the surface opposite to the release sheet faced the inside of the dies (the side in contact with the injected resin). Next, the mold was clamped, and injected resin (polycarbonate resin) was injected into the mold, resulting in a laminate X in which the surface of transfer sheet 1 opposite the release sheet, a core layer (thickness 2.0 mm) containing the injected resin, and the surface of transfer sheet 3 opposite the release sheet were tightly adhered together. Next, after the mold was opened, the release sheets of transfer sheet 1 and transfer sheet 2 were peeled off from laminate X. Next, ultraviolet irradiation (irradiation dose 800 mJ / cm 2 ) to promote the curing of the hard coat layers A and B. Next, a 3 μm-thick black colored layer was formed by screen printing on part of the surface on the hard coat layer B side, thereby obtaining a surface protection plate of Comparative Example 1. The surface protection plate of Comparative Example 1 had, from the front side to the back side, hard coat layer A (a hard coat layer having an uneven surface), adhesive layer A, core layer, adhesive layer B, hard coat layer B, and colored layer (note: the colored layer was formed partially, not entirely).

[0140] Next, a plastic film (a uniaxially oriented polyester film manufactured by Toyobo Co., Ltd., product name "Cosmoshine", in-plane phase difference (internal retardation): 8400 nm) was laminated on the back side (hard coat layer B side) of the surface protection plate of Comparative Example 1 via an optical adhesive layer (manufactured by Panac Corporation, product name "Panaclean PD-S1", thickness 50 μm) to obtain the laminated member of Comparative Example 1.

[0141] [Table 1]

[0142] As is clear from Table 1, it can be confirmed that the surface protection plates of Examples 1 and 2 can suppress a decrease in visibility when a functional member including a plastic film is attached to the back surface via an adhesive layer. In addition, in Reference Example 1, since functional layer B was formed by lamination, there was a slope at the boundary between the area with the colored layer and the area without the colored layer on the outermost surface on the back side of the surface protection plate, resulting in inferior visibility compared to Examples 1 and 2. [Explanation of symbols]

[0143] 10: Core layer 20A: Functional layer A 20B: Functional layer B 21A: Heat seal layer A 21B: Heat seal layer B 22A: Hard coat layer A 22B: Hard coat layer B 23A: Anti-reflection layer A 24A: Film layer A 30: Colored layer 40: Adhesive layer 50: Plastic film 100: Surface protection plate 200: Laminated material

Claims

1. A surface protection plate having, from a front surface side to a rear surface side, a functional layer A, a core layer mainly composed of a polycarbonate resin, and a functional layer B in this order, and further having a colored layer on a part of a surface of the core layer on the functional layer B side, A surface protection plate in which the position of the surface of the colored layer on the functional layer B side and the position of the surface of the core layer on the functional layer B side in an area not having the colored layer are substantially identical in the thickness direction of the surface protection plate.

2. The surface protection plate according to claim 1 , wherein the average inclination angle of the boundary between the region having the colored layer and the region not having the colored layer on the outermost surface on the rear side of the surface protection plate is 0.10 degrees or less.

3. The surface protection plate according to claim 1 or 2, wherein the area having the colored layer has a total light transmittance of 2% or less.

4. 4. The surface protection plate according to claim 1, wherein the area not having the colored layer has a total light transmittance of 50% or more.

5. The surface protection plate according to any one of claims 1 to 4, wherein the functional layer B has a layer different from the functional layer A.

6. The surface protection plate according to any one of claims 1 to 5, wherein the functional layer A includes a hard coat layer A, and the functional layer B includes a hard coat layer B.

7. The surface protection plate according to claim 6, wherein when the arithmetic mean roughness of the surface of the hard coat layer A is defined as Ra-A and the arithmetic mean roughness of the surface of the hard coat layer B is defined as Ra-B, the relationship Ra-A>Ra-B is satisfied.

8. A laminated member comprising a functional member having at least one plastic film laminated on the back side of the surface protection plate according to any one of claims 1 to 7 via an adhesive layer.

9. The laminated member according to claim 8 , wherein no glass is provided between the adhesive layer and the plastic film located closest to the surface protection plate side of the functional member.

10. The laminated member according to claim 8 or 9, wherein the functional member is a touch panel.

11. An image display device comprising the laminated member according to any one of claims 8 to 10 on a display element, and arranged so that the surface of the laminated member on the functional member side faces the display element side.

12. A method for producing a surface protection plate, comprising the following steps (1) and (2): (1) A process of placing a laminate A having a functional layer A on one side of a pair of injection molding molds, and placing a laminate B having a functional layer B and a colored layer on a portion of the functional layer B on the other side of the molds. (2) A step of clamping the mold, injecting an injection resin into the mold, and obtaining a laminate X in which the laminate A, a core layer containing the injected resin, and the laminate B are tightly adhered together.

13. The laminate A is a transfer sheet A having a functional layer A on a release sheet, and the laminate B is a transfer sheet B having a functional layer B on a release sheet and a colored layer on a part of the functional layer B, the laminate X is a laminate in which a surface of the transfer sheet A opposite to the release sheet, a core layer containing the injected resin, and a surface of the transfer sheet B opposite to the release sheet are closely adhered to each other, The method for producing a surface protection plate according to claim 12, further comprising the following step (3): (3) A step of opening the mold and peeling off the release sheets of transfer sheet A and transfer sheet B from the laminate X.

14. The laminate A is a laminate film A obtained by laminating a film layer A and a functional layer A, and the laminate B is a transfer sheet B having a functional layer B on a release sheet and a colored layer on a part of the functional layer B, the laminate X is a laminate in which a surface of the laminate film A opposite to the functional layer A, a core layer containing the injected resin, and a surface of the transfer sheet B opposite to the release sheet are closely adhered to each other, The method for producing a surface protection plate according to claim 12, further comprising the following step (3): (3) A step of opening the mold and peeling the release sheet of the transfer sheet B from the laminate X.

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